JP2023041927A - Power transmission path switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a configuration which can switch a transmission path of power via an electric actuator.

SOLUTION: A power transmission path switching device 5 switches between a first mode and a second mode. In the first mode, a first friction engagement device 40 is connected by displacing a first driven cam 49 in a direction in which an axial interval with a drive cam 48 increases with rotation of the drive cam 48, and a second friction engagement device 41 is disconnected by displacing a second driven cam 50 in a direction in which the axial interval with the drive cam 48 decreases. In the second mode, the first friction is disconnected by displacing the first driven cam 49 in a direction in which the axial interval with the drive cam 48 decreases, and the second friction engagement device 41 is connected by displacing the second driven cam 50 in a direction in which the axial interval with the drive cam 48 increases.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a power transmission path switching device for switching a power transmission path between an input member and an output member, and a two-speed transmission including the power transmission path switching device.

In recent years, with the trend of reducing the consumption of fossil fuels, research into electric vehicles and hybrid vehicles has progressed and is being implemented in some areas. Electric motors, which are the power source of electric vehicles and hybrid vehicles, differ from internal combustion engines (engines) that work by directly burning fossil fuels. , the maximum torque is generated at start-up), it is not necessary to provide a transmission like a general automobile using an internal combustion engine as a drive source. However, even when an electric motor is used as a drive source, the acceleration performance and high-speed performance can be improved by providing a transmission. Specifically, by providing a transmission, the relationship between the running speed and acceleration of the vehicle is made smoother, closer to that of a vehicle equipped with a gasoline engine and a transmission provided in the power transmission system. can. This point will be described with reference to FIG.

For example, if a power transmission device with a large reduction ratio is placed between the output shaft of the electric motor and the input part of the differential gear connected to the drive wheels, the acceleration (G) and running speed (km/h) of the electric vehicle is as shown by the solid line a in FIG. That is, although the acceleration performance at low speed is excellent, high speed running becomes impossible. On the other hand, when a power transmission device with a small reduction ratio is arranged in the intermediate portion, the relationship becomes like the chain line b in FIG. In other words, high-speed running becomes possible, but the acceleration performance at low speeds is impaired. On the other hand, if a transmission is provided between the output shaft and the input portion, and the reduction ratio of this transmission is changed according to the vehicle speed, the portion of the solid line a to the left of the point P and the chain line It is possible to obtain a characteristic such that the portion on the right side of the point P in b is continuous. This characteristic is almost the same as that of a gasoline engine vehicle having a similar output, as indicated by the dashed line c in FIG. It can be seen that the same performance can be obtained.

Japanese Patent Application Laid-Open No. 5-116549 discloses that the torque of the output shaft of an electric motor is transmitted through a two-speed transmission that combines a pair of planetary gear mechanisms and a pair of brakes. and) a structure for an electric vehicle drive system that transmits to a differential gear is disclosed. In this electric vehicle driving device, the constituent elements of the pair of planetary gear mechanisms are switched between a rotatable state and a non-rotatable state based on switching the connection/disengagement state of the pair of brakes, whereby the electric motor The speed reduction ratio between the output shaft and the differential gear can be switched between two stages of high and low.

JP-A-5-116549

The device described in Japanese Patent Application Laid-Open No. 5-116549 includes friction engagement elements supported by components of a planetary gear mechanism and friction engagement elements supported by a housing by hydraulically operated servo pistons PL and PH. are pressed together to connect (engage) the brakes. However, in electric vehicles and hybrid vehicles, in order to reduce costs and improve power consumption performance by simplifying the system, it is possible to switch the reduction ratio of the two-speed transmission with an electric actuator and eliminate the need for a hydraulic system. desired.

SUMMARY OF THE INVENTION In view of the circumstances as described above, the present invention realizes a power transmission path switching device capable of switching a power transmission path by an electric actuator, and a structure of a two-speed transmission incorporating this power transmission path switching device. It is intended to

The power transmission path switching device of the present invention includes:
a drive cam supported rotatably and not displaceable in the axial direction; a cam device having a first driven cam and a second driven cam axially displaced out of phase;
a first frictional engagement device having at least one first friction plate and at least one first separate plate supported so as to be axially displaceable relative to each other;
a second frictional engagement device having at least one second friction plate and at least one second separate plate supported so as to be axially displaceable relative to each other;
Prepare.

In particular, in the power transmission path switching device of the present invention,
As the drive cam rotates,
The first frictional engagement is achieved by pressing the first friction plate and the first separate plate against each other based on displacing the first driven cam in a direction to widen the axial distance from the driving cam. When the device is connected and the second driven cam is displaced in the direction in which the axial distance from the driving cam is reduced, the force for pressing the second friction plate and the second separate plate against each other is reduced. a first mode in which release disconnects the second frictional engagement device;
By displacing the first driven cam in a direction in which the distance between the first driven cam and the drive cam in the axial direction is reduced, the force that presses the first friction plate and the first separate plate against each other is released, whereby the first (1) Disconnecting the frictional engagement device and displacing the second driven cam in a direction to widen the axial distance from the driving cam causes the second friction plate and the second separate plate to move toward each other. a second mode in which the second friction engagement device is connected by pressing together;
is switched.

The power transmission path switching device of the present invention includes:
The first driven cam is disposed between the first driven cam and the first frictional engagement device, and elastically biases the first driven cam and the first frictional engagement device away from each other. 1 elastic member;
A second driven cam is disposed between the second driven cam and the second frictional engagement device, and elastically biases the second driven cam and the second frictional engagement device away from each other. 2 elastic members;
can be further provided.

The power transmission path switching device of the first aspect of the present invention includes:
The drive cam has a first drive cam surface and a second drive cam surface formed by arranging concave portions and convex portions on the axial side surface with the same cycle and different phases in the circumferential direction, and
The first driven cam has a first driven cam surface on an axial side surface facing the first driving cam surface,
The second driven cam has a second driven cam surface on an axial side surface facing the second driving cam surface, and
The cam device includes a plurality of first rolling elements arranged between the first driving cam surface and the first driven cam surface, and the second driving cam surface and the second driven cam surface. It further comprises a plurality of second rolling elements arranged between.

The power transmission path switching device of the second aspect of the present invention includes:
The drive cam has at least one, preferably a plurality of engagement protrusions protruding in the radial direction,
The first driven cam is formed to extend in the circumferential direction and has at least one, preferably a plurality of, first driven cam grooves with which the engaging protrusions are engaged. 1 driven cam groove has at least a part thereof inclined with respect to the circumferential direction,
The second driven cam is formed to extend in the circumferential direction and has at least one, preferably a plurality of second driven cam grooves with which the engaging projections engage, The second driven cam groove has an opening shape symmetrical with the first driven cam with respect to the axial direction.

A plurality of each of the first friction plates and the first separate plates can be provided, and the first friction plates and the first separate plates can be alternately arranged. A plurality of each of the second friction plates and the second separate plates can be provided, and the second friction plates and the second separate plates can be alternately arranged.

The first friction engagement device may further include a first return spring that elastically biases the first friction plate and the first separate plate in a direction to separate them from each other. The second friction engagement device may further include a second return spring that elastically biases the second friction plate and the second separate plate in a direction to separate them from each other.

The two-speed transmission of the present invention is
an input member;
an output member arranged coaxially with the input member;
a planetary gear mechanism disposed between the input member and the output member with respect to the power transmission direction;
The planetary gear mechanism includes a sun gear, a ring gear arranged coaxially with the sun gear around the sun gear, a carrier arranged coaxially with the sun gear, the sun gear and the ring gear meshing with each other, and the carrier and a plurality of pinion gears supported so as to freely rotate around their own central axis,
A power transmission path switching device for switching a power transmission path between the input member and the output member is further provided.

In the two-speed transmission of the present invention, the power transmission path switching device is the power transmission path switching device of the present invention, and the power transmission path switching device further includes an electric actuator that rotationally drives the drive cam. .

The drive cam may have a wheel gear portion on its outer peripheral surface, and the electric actuator may include a worm that meshes with the wheel gear portion, and a speed change motor that rotationally drives the worm.

The two-speed transmission of the first aspect of the present invention comprises:
the input member is connected to the sun gear so as to rotate integrally with the sun gear;
the output member is connected to the carrier so as to rotate integrally therewith;
one of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the sun gear or the input member but not rotatable;
the other of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the carrier or the output member, but unrotatable;
one of the second friction plate and the second separate plate is supported so as to be axially displaceable relative to a portion, such as a housing, which does not rotate during use, but not to rotate, and ,
The other of the second friction plate and the second separate plate is supported so as to be axially displaceable relative to the ring gear and unrotatable.

The two-speed transmission of the second aspect of the present invention comprises:
the input member is connected to the sun gear so as to rotate integrally with the sun gear;
The ring gear is supported and fixed to a portion such as a housing that does not rotate during use,
one of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the sun gear or the input member but not rotatable;
the other of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the output member and unrotatable;
one of the second friction plate and the second separate plate is supported so as to be axially displaceable relative to the carrier and unrotatable;
And, the other of the second friction plate and the second separate plate is supported so as to be axially displaceable relative to the output member and unrotatable.

In the power transmission path switching device of the present invention, the connection/disengagement states of the first friction engagement device and the second friction engagement device are switched based on rotation of the drive cam, and the drive cam operates the electric motor and the like. It can be rotationally driven by an electric actuator included. In short, according to the power transmission path switching device of the present invention, the power transmission path can be switched by the electric actuator. Further, according to the two-speed transmission of the present invention having the power transmission path switching device of the present invention, the electric actuator can switch the speed reduction ratio between the input member and the output member in two stages of high and low.

FIG. 1 is a cross-sectional view showing a two-speed transmission of a first embodiment of the invention. FIG. 2 is a schematic diagram showing a two-speed transmission of the first example of the embodiment of the invention. FIG. 3A is a schematic diagram showing a power transmission path in high speed mode, and FIG. 3B is a schematic diagram showing a power transmission path in low speed mode. FIG. 4 is a cross-sectional view showing a power transmission path switching device taken out in the first embodiment of the present invention. FIG. 5 is an exploded perspective view showing the cam device and the electric actuator in the first embodiment of the present invention. FIG. 6 is a diagram for explaining the phase relationship in the circumferential direction between the first driving cam surface and the second driving cam surface. FIG. 7A is a cross-sectional view showing the first frictional engagement device, and FIG. 7B is a cross-sectional view showing the second frictional engagement device. FIG. 8 is a cross-sectional view showing a two-speed transmission of a second example of the embodiment of the invention. FIG. 9 is an exploded perspective view showing a cam device and an electric actuator in a second embodiment of the present invention. FIG. 10(A) is a diagram showing the state of engagement between the engagement protrusions and the first driven cam groove and the second driven cam groove in high speed mode, and FIG. 10(B) is a diagram in low speed mode. is a diagram showing the state of engagement between the engagement convex portion of No. 1 and the first driven cam groove and the second driven cam groove. FIG. 11 is a cross-sectional view showing a two-speed transmission according to a third embodiment of the invention. FIG. 12 is a schematic diagram showing a two-speed transmission according to a third embodiment of the invention. FIG. 13A is a schematic diagram showing a power transmission path in high speed mode, and FIG. 13B is a schematic diagram showing a power transmission path in low speed mode. FIG. 14 is a diagram for explaining the effect of incorporating a transmission into a drive device using an electric motor as a drive source.

[First example of embodiment]
1 to 7 show a first example of an embodiment of the invention. This example is an example in which the power transmission path switching device of the first aspect of the present invention is applied to the two-speed transmission of the first aspect of the present invention. The two-speed transmission 1 of this example is arranged, for example, between the output shaft of an electric motor, which is the power source of an electric vehicle or a hybrid vehicle, and a differential gear, and increases the torque of the output shaft of the electric motor. After (deceleration), or without increasing (deceleration), it is transmitted to the differential gear as it is. The two-speed transmission of this example includes an input member 2, an output member 3, a planetary gear mechanism 4, and a power transmission path switching device 5, and a reduction ratio between the input member 2 and the output member 3 can be switched between high and low levels.

The input member 2 is connected to a drive shaft (not shown) such as an output shaft of an electric motor, and receives torque (power). In this example, the input member 2 includes an input tubular portion 6 and an input flange portion bent radially outward from one axial end (right side in FIGS. 1 to 4) of the input tubular portion 6. 7. The drive shaft is, for example, fitted inside the inner peripheral surface of the input tubular portion 6 so as to transmit torque, or coupled to the input flange portion 7 by bolting or the like so as to be able to transmit torque.

The output member 3 is arranged coaxially with the input member 2, is connected to a driven shaft (not shown) such as a differential gear or a propeller shaft, and outputs torque to the driven shaft. In this example, the output member 3 includes an output tubular portion 9 having a female spline portion 8 on its inner peripheral surface, and an end portion on the other axial side (left side in FIGS. 1 to 4) of the output tubular portion 9. and an output flange portion 10 that is bent radially outward. The driven shaft is connected to the output member 3 so as to transmit torque by spline-engaging the male spline portion provided on the outer peripheral surface of the distal end portion with the female spline portion 8 of the output tubular portion 9 .

The planetary gear mechanism 4 is arranged between the input member 2 and the output member 3 with respect to the power transmission direction, and includes a sun gear 11 , a ring gear 12 , a carrier 13 and a plurality of pinion gears 14 .

The sun gear 11 is connected to the input member 2 so as to rotate together therewith. In this example, the sun gear 11 includes a small-diameter cylindrical portion 15 on one side in the axial direction, a large-diameter cylindrical portion 16 on the other side in the axial direction, and an end portion of the large-diameter cylindrical portion 16 on the other side in the axial direction that is bent radially outward. and a flange portion 17 . The sun gear 11 includes a sun-side male spline portion 18 on the outer peripheral surface of the large-diameter cylindrical portion 16 and a gear portion 19 that is a spur gear or a helical gear on the outer peripheral surface of the flange portion 17 . The sun gear 11 has a small-diameter cylindrical portion 15 externally fitted to the input cylindrical portion 6 of the input member 2 by a structure capable of transmitting torque, such as spline engagement.

The ring gear 12 is supported around the sun gear 11 coaxially with the sun gear 11 and rotatable relative to the sun gear 11 . In this example, the ring gear 12 includes a small-diameter cylindrical portion 20 on one side in the axial direction, a large-diameter cylindrical portion 21 on the other side in the axial direction, an end portion of the small-diameter cylindrical portion 20 on the other side in the axial direction, and the large-diameter cylindrical portion 21 . and a circular ring portion 22 that connects the end portion on one side in the axial direction of the . The ring gear 12 has a ring-side male spline portion 23 on the outer peripheral surface of the small-diameter cylindrical portion 20 and a gear portion 24 that is a spur gear or a helical gear on the inner peripheral surface of the large-diameter cylindrical portion 21 .

The carrier 13 is coaxially supported by the sun gear 11 and the ring gear 12 and connected to the output member 3 so as to rotate integrally with the output member 3 . In this example, the carrier 13 comprises a pair of rims 25a, 25b, each of which is annular and spaced apart in the axial direction, and one of the pair of rims 25a, 25b that is aligned with each other. A column portion 26 (see FIG. 11 to be described later) that spans between a plurality of locations in the circumferential direction, and the radial direction of one side surface of the rim portion 25a on one side in the axial direction of the pair of rim portions 25a and 25b. A cylindrical portion 27 protrudes from the intermediate portion toward one side in the axial direction over the entire circumference.

The carrier 13 is provided with circular holes 28a penetrating in the axial direction at a plurality of locations in the circumferential direction of a portion of the rim portion 25a on one side in the axial direction, which is located radially outside the tubular portion 27, and has a tubular shape. A carrier-side female spline portion 29 is provided on the inner peripheral surface of the portion 27 . Further, the carrier 13 axially penetrates a portion of the rim portion 25b on the other side in the axial direction of the pair of rim portions 25a and 25b that is aligned with the circular hole 28a of the rim portion 25a on the one side in the axial direction. It has a circular hole 28b for The carrier 13 rotates integrally with the output member 3 by connecting the rim portion 25b on the other side in the axial direction to the output flange portion 10 of the output member 3 by a structure capable of transmitting torque such as spline engagement. is configured to

Each pinion gear 14 meshes with the sun gear 11 and the ring gear 12, and is supported by the carrier 13 so as to be freely rotatable about its central axis. In this example, each of the pinion gears 14 has a cylindrical body portion 31 rotatably supported by a radial needle bearing 32 around a cylindrical support shaft 30 in an axially intermediate portion. The main body portion 31 has a gear portion 33 which is a spur gear or a helical gear and meshes with the gear portion 19 of the sun gear 11 and the gear portion 24 of the ring gear 12 on its outer peripheral surface. The support shaft 30 has both ends in the axial direction fitted and fixed to the circular holes 28 a and 28 b of the carrier 13 .

In this example, the other axial side surface of the spacer 35, whose displacement to one side in the axial direction is prevented by the retaining ring 34a engaged with the axially intermediate portion of the large-diameter cylindrical portion 16 of the sun gear 11, is abutted against one axial side surface of the radially inner portion of the rim portion 25a via a thrust bearing 36a. Further, a retaining ring 34b engaged with the end portion of the large-diameter cylindrical portion 21 of the ring gear 12 on the other axial side prevents displacement to the other axial side of the pressing plate 37, and the axial piece of the radially inner portion of the holding plate 37 The side surface abuts against the other axial side surface of the radially inner portion of the rim portion 25b (the output flange portion 10 of the output member 3) on the other axial side via the thrust bearing 36b. Accordingly, separation of the sun gear 11, the ring gear 12, the carrier 13, and the pinion gear 14 can be prevented when the planetary gear mechanism 4 is assembled. In short, the planetary gear mechanism 4 can be handled integrally as a subassembly.

The power transmission path switching device 5 switches the power transmission path between the input member 2 and the output member 3 . The power transmission path switching device 5 of this example includes a housing 38 that does not rotate during use, a cam device 39 , a first frictional engagement device 40 and a second frictional engagement device 41 .

The housing 38 connects the inner diameter side tubular portion 42, the outer diameter side tubular portion 43, one axial end portion of the inner diameter side tubular portion 42, and one axial end portion of the outer diameter side tubular portion 43. A ring-shaped side plate portion 44 is provided. The housing 38 includes a fixed-side male spline portion 45 on the outer peripheral surface of the inner diameter-side tubular portion 42 and a fixed-side female spline portion 46 on the inner peripheral surface of the outer diameter-side tubular portion 43 . In addition, the housing 38 further includes a through hole 47 that penetrates in the radial direction and extends in the circumferential direction on one axial side portion of the outer diameter side tubular portion 43 .

In this example, a radial needle bearing 78 is arranged between the inner peripheral surface of the inner cylindrical portion 42 of the housing 38 and the outer peripheral surface of the input cylindrical portion 6 of the input member 2, and the axial direction of the side plate portion 44 is arranged. By disposing a thrust needle bearing 79 between one side surface and the other axial side surface of the input flange portion 7 , the input member 2 is rotatably supported with respect to the housing 38 .

The cam device 39 includes a drive cam 48 that is rotatably supported so as not to be displaced in the axial direction, and a cam device 39 that is supported so as to be rotatable and axially displaced relative to the drive cam 48, and is rotatable with respect to the rotation of the drive cam 48. Along with this, it is provided with a first driven cam 49 and a second driven cam 50 that are axially displaced in phases different from each other. It should be noted that the displacement in the axial direction with mutually different phases means that the first driven cam 49 and the second driven cam 50 move in opposite directions in the axial direction as the drive cam 48 rotates, as will be described later. It means to displace (advance and retreat). That is, when the first driven cam 49 moves toward one side in the axial direction, the second driven cam 50 moves toward the other side in the axial direction. When moving toward the other side, the second driven cam 50 moves toward one side in the axial direction.

The drive cam 48 has a circular ring shape, and is mounted on the outer peripheral surface of one end in the axial direction of the inner diameter side cylindrical portion 42 of the housing 38 via an angular ball bearing 51 capable of supporting a radial load and a thrust load. It is rotatably supported and axially displaceable.

The driving cam 48 has a first driving cam surface 52 and a second driving cam, which are formed by arranging concave portions and convex portions on the other side surface in the axial direction with the same cycle and different phases (opposite phases) with respect to the circumferential direction. It has a face 53 . That is, the drive cam 48 has a first drive cam surface 52 on the radially inner portion of the other axial side surface, and a second drive cam surface 53 on the radially outer portion of the other axial side surface. In this example, each of the first driving cam surface 52 and the second driving cam surface 53 has the same number of concave portions and convex portions (three each in the illustrated example) alternately in the circumferential direction and The directional phases are shifted by half a period (60 degrees in the illustrated example) (in opposite phases). That is, as shown in FIG. 6, in the circumferential direction, the convex portion of the first drive cam surface 52 is in phase with the concave portion of the second drive cam surface 53 in phase. The concave portion of the driving cam surface 52 is in phase with the convex portion of the second driving cam surface 53 in phase. The first drive cam surface 52 has a flat surface portion 54a perpendicular to the central axis of the drive cam 48 on the tip end surface of the projection, and the second drive cam surface 53 has a flat surface portion 54a on the tip end surface of the projection. It has a flat surface portion 54b perpendicular to the central axis of the drive cam 48 . It should be noted that each of the first drive cam surface 52 and the second drive cam surface 53 is not limited to a shape symmetrical with respect to the circumferential direction as shown in FIG. 6, and various shapes can be adopted.

The drive cam 48 further has a wheel gear portion 55, which is a helical gear having a helical tooth trace, on the outer peripheral surface.

The drive cam 48 is rotationally driven by an electric actuator 56 . The electric actuator 56 includes a worm 57 and a speed change motor 58 . The worm 57 has a worm gear portion 59 that meshes with the portion of the wheel gear portion 55 of the drive cam 48 that is exposed from the through hole 47 of the housing 38 on the outer peripheral surface of the axially intermediate portion. The speed change motor 58 drives the worm 57 to rotate. That is, the drive cam 48 is rotationally driven by the transmission motor 58 via a worm speed reducer formed by meshing the wheel gear portion 55 and the worm gear portion 59 .

The first driven cam 49 is arranged to face the radially inner portion of the drive cam 48 in the axial direction. The first driven cam 49 has the same number of recesses and projections as the number of recesses and projections of the first drive cam surface 52 on one side surface of the drive cam 48 in the axial direction facing the first drive cam surface 52 (this is the same number). three in the example) have first driven cam surfaces 60 that alternate in the circumferential direction. However, the first driven cam surface 60 facing the first driving cam surface 52 can also be configured by a flat surface orthogonal to the central axis.

The first driven cam 49 has a first driven side female spline portion 61 on its inner peripheral surface, and the first driven side female spline portion 61 is connected to the fixed side male spline portion 45 of the housing 38 . Due to the spline engagement, it is supported with respect to the housing 38 so that it can only be displaced in the axial direction.

The second driven cam 50 is arranged axially facing the radially outer portion of the drive cam 48 . The second driven cam 50 has the same number of recesses and projections as the number of recesses and projections of the second drive cam surface 53 on one side surface of the drive cam 48 in the axial direction facing the second drive cam surface 53 (this is the same number). three in the example) have second driven cam surfaces 62 that alternate in the circumferential direction. However, the second driven cam surface 62 facing the second driving cam surface 53 can also be configured by a flat surface perpendicular to the central axis.

The second driven cam 50 has a second driven side male spline portion 63 on its outer peripheral surface, and the second driven side male spline portion 63 is splined to the fixed side female spline portion 46 of the housing 38 . By engaging them, they are supported so that they can only be displaced in the axial direction with respect to the housing 38 .

The cam device 39 of this example includes a plurality of first rolling elements 64 rotatably arranged between the first driving cam surface 52 and the first driven cam surface 60, and a second driving cam surface. Between 53 and the second driven cam surface 62, there are further provided a plurality of second rolling elements 65 that are rollably arranged. That is, in this example, as the driving cam 48 rotates, the first rolling element 64 rides on the bottom of the concave portion of the first driving cam surface 52 and the distance from the bottom of the concave portion of the first driven cam surface 60 increases. As the riding amount increases or decreases, the first driven cam 49 is displaced in the axial direction, and the amount of riding of the second rolling element 65 from the bottom of the concave portion of the second driving cam surface 53 and the second driven cam surface increase or decrease. The second driven cam 50 is displaced in the axial direction by increasing or decreasing the riding amount from the bottom of the recess 62 . Although balls are used as the first rolling elements 64 and the second rolling elements 65 in this example, rollers can also be used as the first rolling elements and the second rolling elements.

In this example, each of the first driving cam surface 52 and the second driving cam surface 53 of the driving cam 48 has the same number of concave portions and convex portions, alternately in the circumferential direction, and half in phase in the circumferential direction. They are arranged with a period shift (in opposite phase). Therefore, as the drive cam 48 rotates, the first driven cam 49 and the second driven cam 50 are displaced (advance and retreat) in opposite directions with respect to the axial direction. Specifically, when the first driven cam 49 moves toward one side in the axial direction, the second driven cam 50 moves toward the other side in the axial direction, whereas the first driven cam 49 moves toward the other side in the axial direction. moves toward the other side in the axial direction, the second driven cam 50 moves toward the one side in the axial direction.

The first friction engagement device 40 has a plurality of first friction plates 66 and first separate plates 67 . The first friction plates 66 and the first separate plates 67 each have a substantially ring shape and are alternately arranged in the axial direction. In this example, the first frictional engagement device 40 is disposed between the sun gear 11 and the carrier 13, and the sun gear 11 and the carrier 13, which are rotating bodies, rotate integrally and mutually. It functions as a clutch that switches between the state of relative rotation.

Each of the first friction plates 66 has a female spline portion on its inner peripheral surface, and the female spline portion is spline-engaged with the sun-side male spline portion 18 of the sun gear 11 so that the sun gear 11 is axially engaged with the sun gear 11 . It is supported to allow only directional displacement.

Each of the first separate plates 67 has a male spline portion on its outer peripheral surface, and the male spline portion is spline-engaged with the carrier-side female spline portion 29 of the carrier 13 , thereby axially moving the carrier 13 . Only the displacement of the support is possible.

Of the first separate plates 67 , the first separate plate 67 that exists on the other side in the axial direction is axially disengaged by a retaining ring 68 that is engaged with the end portion on the other side in the axial direction of the cylindrical portion 27 of the carrier 13 . Displacement to the other side is blocked.

Among the first separate plates 67, between the first separate plate 67 existing on one side in the axial direction and the first driven cam 49, in order from one side in the axial direction, a first elastic member 69 and a thrust rolling bearing are provided. 70 are sandwiched. The first elastic member 69 elastically urges the first friction engagement device 40 and the first driven cam 49 in directions away from each other in the axial direction. In addition, in this example, the first elastic member 69 is configured by a disc spring. However, the first elastic member 69 can also be configured by a torsion coil spring or the like.

The first friction engagement device 40 separates the first friction plate 66 and the first separate plate 67 from each other, and is elastic in the direction of releasing the force of pressing the first friction plate 66 and the first separate plate 67 against each other. A positively biasing first return spring 108 is further provided. In this example, as shown in FIG. 7A, the first return spring 108 is arranged between the first separate plate 67 located on one side in the axial direction and the first separate plate 67 located on the other side in the axial direction. It spans between them and elastically urges the first separate plate 67 on one side in the axial direction and the first separate plate 67 on the other side in the axial direction to move away from each other.

The second friction engagement device 41 has a plurality of second friction plates 72 and second separate plates 73 . The second friction plates 72 and the second separate plates 73 are each substantially annular and arranged alternately in the axial direction. In this example, the second friction engagement device 41 is arranged between the ring gear 12 and the housing 38 and functions as a brake that switches between a state in which the ring gear 12 is allowed to rotate and a state in which it is blocked.

Each of the second friction plates 72 has a female spline portion on its inner peripheral surface, and by spline-engaging the female spline portion with the ring-side male spline portion 23 of the ring gear 12 , the ring gear 12 is axially rotated. It is supported to allow only directional displacement.

Each of the second separate plates 73 has a male spline portion on its outer peripheral surface, and by spline-engaging the male spline portion with the fixed-side female spline portion 46 of the housing 38 , it is axially moved relative to the housing 38 . Only the displacement of the support is possible.

Of the second separate plates 73 , the second separate plate 73 that exists on the other side in the axial direction is secured by a snap ring 74 that is engaged with the end portion on the other side in the axial direction of the outer diameter side tubular portion 43 of the housing 38 . Displacement to the other side in the axial direction is prevented.

Among the second separate plates 73, between the second separate plate 73 that exists on one side in the axial direction and the second driven cam 50, a second elastic member 75 and a substantially L-shaped and a spacer 76 having a cross-sectional shape of . The second elastic member 75 elastically urges the second friction engagement device 41 and the second driven cam 50 in directions away from each other in the axial direction. In addition, in this example, the second elastic member 75 is configured by a disc spring. However, the second elastic member 75 can also be configured by a torsion coil spring or the like.

The second friction engagement device 41 separates the second friction plate 72 and the second separate plate 73 from each other, and releases the force of the second friction plate 72 and the second separate plate 73 pressing against each other. It further comprises a second return spring 109 that is elastically biased. In this example, as shown in FIG. 7(B), the second return spring 109 is arranged between the second separate plate 73 located on one side in the axial direction and the second separate plate 73 located on the other side in the axial direction. It spans between them and elastically urges the second separate plate 73 present on one side in the axial direction and the second separate plate 73 present on the othermost side in the axial direction in a direction away from each other.

The power transmission path switching device 5 rotationally drives the driving cam 48 by the electric actuator 56, and displaces the first driven cam 49 and the second driven cam 50 in the axial direction to achieve the first frictional engagement. The connection/disconnection state between the device 40 and the second friction engagement device 41 is switched. Specifically, the power transmission path switching device 5 of this example has a first mode in which the first frictional engagement device 40 is connected and the second frictional engagement device 41 is disconnected, and a first mode in which the first frictional engagement device 41 is disconnected. Switching to the second mode in which the device 40 is disconnected and the second friction engagement device 41 is connected. Each case will be described below.

<First mode>
In order to switch the power transmission path switching device 5 to the first mode, the drive cam 48 is rotationally driven by the electric actuator 56, and the first drive cam surface of the first rolling element 64 is moved as indicated by the two-dot chain line in FIG. By increasing the amount by which the first driven cam surface 60 rides over the bottom of the concave portion 52 and the amount by which the first driven cam surface 60 rides over the bottom portion of the concave portion, the first driven cam 49 is moved in the direction in which the axial distance from the driving cam 48 increases ( and the amount by which the second rolling element 65 rides over the bottom of the recess of the second driving cam surface 53 and the amount of running over the bottom of the recess of the second driven cam surface 62 is determined by By decreasing, the second driven cam 50 is displaced in a direction (one side in the axial direction) in which the axial distance from the drive cam 48 is reduced. In this example, when the power transmission path switching device 5 is switched to the first mode (switching to the first mode is completed), the first rolling element 64 moves toward the flat surface portion of the first drive cam surface 52. It runs on 54a.

When the first driven cam 49 is displaced toward one side in the axial direction, the first separate plate 67 located on the farthest one side in the axial direction moves toward the other side in the axial direction via the first elastic member 69 and the thrust rolling bearing 70 . pressed. Based on this, the first friction plate 66 and the first separate plate 67 are pressed against each other, thereby connecting the first friction engagement device 40 .

On the other hand, when the second driven cam 50 is displaced toward one side in the axial direction, the force with which the second friction plate 72 and the second separate plate 73 press each other is released. As a result, due to the action of the second return spring 109, the distance between the second separate plate 73 located on one side in the axial direction and the second separate plate 73 located on the other side in the axial direction widens, thereby increasing the second friction. The engagement device 41 is disconnected.

<Second mode>
In order to switch the power transmission path switching device 5 to the second mode, the drive cam 48 is rotationally driven by the electric actuator 56, and the first drive cam surface 52 of the first rolling element 64 is rotated as indicated by the dashed line in FIG. By reducing the amount by which the first driven cam surface 60 rides over the bottom of the recess and the amount by which the first driven cam surface 60 rides over the bottom of the recess, the first driven cam 49 is moved in the direction in which the axial distance from the drive cam 48 decreases (axis direction one side), and increase the amount of the second rolling element 65 riding over the bottom of the recess of the second drive cam surface 53 and the amount of riding over the bottom of the recess of the second driven cam surface 62. As a result, the second driven cam 50 is displaced in the direction in which the axial distance from the drive cam 48 increases (the other side in the axial direction). In this example, when the power transmission path switching device 5 is switched to the second mode (switching to the second mode is completed), the second rolling element 65 moves toward the flat surface portion of the second drive cam surface 53. It runs on 54b.

The first driven cam 49 is displaced toward one side in the axial direction, and the force of pressing the first friction plate 66 and the first separate plate 67 against each other is released. As a result, due to the action of the first return spring 108, the distance between the first separate plate 67 located on one side in the axial direction and the first separate plate 67 located on the other side in the axial direction widens, thereby increasing the first frictional force. The engagement device 40 is disconnected.

On the other hand, when the second driven cam 50 is displaced toward the other side in the axial direction, the second separate plate 73 located on the farthest one side in the axial direction moves toward the other side in the axial direction via the second elastic member 75 and the spacer 76 . is pressed down. Based on this, the second frictional engagement device 41 is connected by the second friction plate 72 and the second separate plate 73 pressing against each other.

By switching the operation mode of the power transmission path switching device 5, the two-speed transmission 1 of this example has a high speed mode in which the reduction ratio between the input member 2 and the output member 3 is small (the reduction ratio is 1). , and a low-speed mode having a larger reduction ratio than the high-speed mode. Each case will be described below.

<High speed mode>
In order to switch the two-speed transmission 1 to the high-speed mode, the power transmission path switching device 5 is connected to the first friction engagement device 40 based on the rotation of the drive cam 48 by the electric actuator 56, and Switch to the first mode in which the second friction engagement device 41 is disconnected. When the power transmission path switching device 5 is switched to the first mode, the sun gear 11 and the carrier 13 are rotated integrally based on the connection of the first frictional engagement device 40, and the first mode is switched. Rotation of the ring gear 12 with respect to the housing 38 is permitted based on the disengagement of the two friction engagement devices 41 . In such a high-speed mode, the sun gear 11, the ring gear 12, and the carrier 13 rotate in the same direction and at the same rotational speed, so that the entire planetary gear mechanism 4 rotates together, resulting in a so-called glued state. Therefore, the power of the input member 2 is transmitted to the output member 3 through the route shown in (A) below.
(A) Input member 2 → carrier 13 → output member 3
Thus, in the high speed mode, the power of the input member 2 is transmitted to the output member 3 without being decelerated. In other words, in high speed mode the reduction ratio between the input member 2 and the output member 3 is unity.

<Low speed mode>
In order to switch the two-speed transmission 1 to the low speed mode, the power transmission path switching device 5 is disconnected, the first frictional engagement device 40 is disconnected, and The mode is switched to the first mode in which the second friction engagement device 41 is connected. When the power transmission path switching device 5 is switched to the second mode, the sun gear 11 and the carrier 13 become rotatable relative to each other based on the disengagement of the first frictional engagement device 40, and the second frictional engagement is established. Rotation of the ring gear 12 with respect to the housing 38 is prevented by connecting the coupling device 41 . In such a low speed mode, the power of the input member 2 is transmitted to the output member 3 through the route shown in (B) below.
(B) Input member 2 → Sun gear 11 → Rotational motion of pinion gear 14 → Revolving motion of pinion gear 14 based on engagement with ring gear 12 → Carrier 13 → Output member 3
Thus, in the low speed mode, the power of the input member 2 is reduced by the planetary gear mechanism 4 and transmitted to the output member 3 . The reduction ratio between the input member 2 and the output member 3 in the low speed mode is the gear ratio between the ring gear 12 and the sun gear 11 (the number of teeth of the gear portion 24 of the ring gear 12/the number of teeth of the gear portion 19 of the sun gear 11). ).

As described above, in the two-speed transmission 1 of this example, the operation mode of the power transmission path switching device 5 is switched, that is, the connection/disengagement states of the first friction engagement device 40 and the second friction engagement device 41 are switched. As a result, the speed reduction ratio between the input member 2 and the output member 3 can be switched between high and low levels. Specifically, when the power input to the input member 2 is low speed and high torque, the two-speed transmission 1 is switched to the low speed mode, and when it is high speed and low torque, it is switched to the high speed mode. For this reason, the acceleration performance and high-speed performance when an electric vehicle or a hybrid vehicle is running using only an electric motor as a drive source are defined by the left side of the point P in the solid line a in FIG. The characteristic is such that the part on the right side of the point P is continuous, and can be made close to the gasoline engine vehicle indicated by the dashed line c in FIG. 14 .

In particular, in the power transmission path switching device 5 of this example, the first friction engagement device 40 and the first friction engagement device 40 and the The connection/disconnection state of the second friction engagement device 41 is switched. That is, the power transmission path switching device 5 of this example does not require a hydraulic system for controlling friction engagement devices such as clutches and brakes. Therefore, in an electric vehicle or a hybrid vehicle, the system can be simplified, the cost can be reduced, and the power consumption performance can be improved.

Further, when the drive cam 48 is rotationally driven to switch the mode between the low speed mode and the high speed mode, the first driven cam 49 and the second driven cam 50 are displaced (advance/retreat) in opposite directions with respect to the axial direction. )do. Therefore, at the time of mode switching, the larger the fastening force of one of the first frictional engagement device 40 and the second frictional engagement device 41, the smaller the fastening force of the other frictional engagement device. . Therefore, it is possible to suppress the shift shock due to the mode switching, thereby preventing the vehicle occupants from feeling uncomfortable.

In this example, the first elastic member 69 is arranged between the first separate plate 67 and the first driven cam 49, which are located on the farthest one side in the axial direction, and the second separate plate, which is located on the farthest one side in the axial direction. A second elastic member 75 is arranged between 73 and the second driven cam 50 . Therefore, the assembly error of the power transmission path switching device 5 and the deviation due to wear of the first friction plate 66, the first separate plate 67, the second friction plate 72 and the second separate plate 73 can be 2 can be absorbed by the elastic member 75 . Therefore, by controlling the force that presses the first driven cam 49 (the force that presses the first driven cam 49 against the first separate plate 67, which is located on one side in the axial direction, toward the other side in the axial direction), the 1. The fastening force of the friction engagement device 40 can be controlled, and the force pressing the second driven cam 50 (the axis of the second driven cam 50 with respect to the second separate plate 73 existing on one side in the axial direction) The fastening force of the second friction engagement device 41 can be controlled by controlling the pressing force to the other direction. As a result, in the high speed mode, a sufficient fastening force of the first frictional engagement device 40 can be secured, and in the low speed mode, a sufficient fastening force of the second frictional engagement device 41 can be secured. can be done.

In this example, when the power transmission path switching device 5 is switched to the first mode and the first frictional engagement device 40 is connected, the first rolling element 64 is positioned on the tip surface of the convex portion of the first drive cam surface 52. It rides on the provided flat surface portion 54a. On the other hand, when the power transmission path switching device 5 is switched to the second mode and the second frictional engagement device 41 is connected, the second rolling element 65 is provided on the tip surface of the convex portion of the second drive cam surface 53 . It rides on the flat surface portion 54b. Therefore, according to the power transmission path switching device 5 of the present embodiment, even if the power supply to the transmission motor 58 is stopped after the mode switching is completed, the connected state of the first frictional engagement device 40 or the second frictional engagement is maintained. The connected state of the device 41 can be maintained, and from this point of view as well, the power consumption performance can be improved.

Instead of or in addition to providing the flat surface portions 54a and 54b on the distal end surfaces of the convex portions of the first drive cam surface 52 and the second drive cam surface 53, the driving By providing a self-locking function to the worm reduction gear consisting of the wheel gear portion 55 of the cam 48 and the worm gear portion 59 of the worm 57, the connection of the first friction engagement device 40 can be maintained even after the power supply to the shift motor 58 is stopped. The state or the connected state of the second friction engagement device 41 may be maintained.

In the two-speed transmission 1 of this example, the planetary gear mechanism 4 is arranged around the output member 3 and the power transmission path switching device 5 is arranged around the input member 2. When implementing the two-speed transmission of the first aspect of the invention, not limited to this, various configurations can be employed. For example, the planetary gear mechanism can be arranged around the input member and the power transmission path switching device can be arranged around the output member. Alternatively, the planetary gear mechanism and/or the power transmission path switching device can be arranged without radially overlapping the input member or the output member. In any case, the shape of each part is appropriately changed according to each configuration.

In addition, the cam device 39 of the power transmission path switching device 5 of this example has the first rolling element 64 and the second rolling element 64 between the driving cam 48 and the first driven cam 49 and the second driven cam 50, respectively. A moving body 65 is sandwiched. However, when implementing the power transmission path switching device of the present invention, if the first driven cam and the second driven cam can be displaced in opposite directions with respect to the axial direction with the rotation of the drive cam, this is acceptable. Without limitation, various configurations can be adopted. For example, a first driving cam surface and a second driving cam surface provided on the driving cam, and a first driven cam surface provided on the first driven cam and a second driven cam surface provided on the second driven cam. The cam surface can also be brought into direct sliding contact.

[Second example of embodiment]
8 to 10B show a second example of the embodiment of the invention. This example is an example in which the power transmission path switching device of the second aspect of the invention is applied to the two-speed transmission of the first aspect of the invention. That is, in the two-speed transmission 1a of this example, the structure of the cam device 39a of the power transmission path switching device 5a is different from the structure of the cam device 39 of the first example of the embodiment.

The cam device 39a of this example has a driving cam 48a, a first driven cam 49a and a second driven cam 50a.

The drive cam 48a includes a plurality of (for example, three or four) engaging protrusions 80 protruding in the radial direction. In this example, the drive cam 48a includes an annular side plate portion 81, an inner diameter side cylindrical portion 82 bent from the radially inner end portion of the side plate portion 81 toward the other side in the axial direction, and the side plate portion 81. An outer diameter side cylindrical portion 83 protruding from the radially outer portion toward the other side in the axial direction over the entire circumference is provided. The drive cam 48a further includes circular holes 84 radially penetrating the outer diameter side cylindrical portion 83 at a plurality of locations in the circumferential direction of the outer diameter side cylindrical portion 83. Each of the circular holes 84 is provided with an engaging pin. 85 is press-fitted. In this example, the engaging convex portion 80 is configured by a portion of the engaging pin 85 that protrudes radially inward from the inner peripheral surface of the outer diameter side tubular portion 83 . Further, the drive cam 48a further has a wheel gear portion 55a, which is a helical gear having a helical tooth trace, on the outer peripheral surface of the side plate portion 81. As shown in FIG.

The drive cam 48a is mounted on the housing 38 by arranging the angular ball bearing 51 between the inner peripheral surface of the inner diameter side tubular portion 82 and the outer peripheral surface of the end portion of the inner diameter side tubular portion 42 of the housing 38 on one side in the axial direction. It is supported so as to be rotatable with respect to it and to be axially displaceable.

The first driven cam 49a is formed to extend in the circumferential direction and has a plurality of first driven cam grooves 86 with which the engaging projections 80 engage. In this example, the first driven cam 49a includes an annular side plate portion 87, an outer diameter side cylindrical portion 88 bent from the radially outer end portion of the side plate portion 87 toward one side in the axial direction, and the side plate portion 87. An inner diameter side tubular portion 89 protrudes from the radially intermediate portion of the portion 87 toward the other side in the axial direction over the entire circumference.

Each of the first driven cam grooves 86 is formed on the outer peripheral surface of the outer diameter side tubular portion 88 . The first driven cam groove 86 has a linear portion 90a arranged on one side in the circumferential direction (upper side in FIGS. 10A and 10B) and one side in the axial direction when viewed from the radially outer side, A linear portion 90b arranged on the other side in the direction (lower side in FIGS. 10A and 10B) and on the other side in the axial direction, an end portion of the linear portion 90a on the other side in the circumferential direction, and the linear portion 90b and an inclined portion 91 connecting to one end in the circumferential direction of 90b. That is, the inclined portion 91 is inclined in a direction from one side to the other side in the axial direction as it goes from one side to the other side in the circumferential direction when viewed from the radially outer side.

Each of the first driven cam grooves 86 opens only on the outer peripheral surface of the outer diameter side tubular portion 88 and does not open on the inner peripheral surface of the outer diameter side tubular portion 88 . That is, in this example, the first driven cam groove 86 is configured by a concave groove. However, the first driven cam groove 86 can also be formed so as to penetrate the outer diameter side cylinder portion 88 in the radial direction.

The first driven cam 49 a has a first driven side female spline portion 61 a on the inner peripheral surface of the side plate portion 87 , and the first driven side female spline portion 61 a is attached to the fixed side male spline portion of the housing 38 . By spline engagement with the spline portion 45, it is supported with respect to the housing 38 so as to be displaceable only in the axial direction.

The second driven cam 50a is formed to extend in the circumferential direction and has a plurality of second driven cam grooves 92 with which the engaging projections 80 engage. In this example, the second driven cam 50a includes a small-diameter tubular portion 93 on one axial side, a large-diameter tubular portion 94 on the other axial side, an end portion of the small-diameter tubular portion 93 on the other axial side, and a large-diameter tubular portion 94 on the other axial side. A circular ring portion 95 that connects one end portion of the diameter cylindrical portion 94 in the axial direction is provided.

Each of the second driven cam grooves 92 is formed in the small-diameter cylindrical portion 93 so as to penetrate the small-diameter cylindrical portion 93 in the radial direction. The second driven cam groove 92 has an opening shape symmetrical with the first driven cam groove 86 in the axial direction. That is, the second driven cam groove 92 has a linear portion 96a arranged on one side in the circumferential direction and on the other side in the axial direction, and a straight portion 96a arranged on the other side in the circumferential direction and on one side in the axial direction. and an inclined portion 97 connecting the other end of the linear portion 96a in the circumferential direction and the one end of the linear portion 96b in the circumferential direction. That is, the inclined portion 97 is inclined in a direction from the other side in the axial direction to the other side as it goes from one side in the circumferential direction to the other side when viewed from the outside in the radial direction.

The second driven cam 50a has a second driven side male spline portion 63a on the outer peripheral surface of one end of the large-diameter cylindrical portion 94 in the axial direction. The second driven cam 50a is supported with respect to the housing 38 so as to be displaceable only in the axial direction by spline-engaging the second driven side male spline portion 63a with the fixed side female spline portion 46 of the housing 38. ing.

In the cam device 39a of the present example, the intermediate portion of the engagement projection 80 of the drive cam 48a engages (passes through) the second driven cam groove 92 of the second driven cam 50a, and the engagement projection A tip portion (radially inner end portion) of 80 is engaged with a first driven cam groove 86 of the first driven cam 49a. Therefore, when the electric actuator 56 rotates the drive cam 48a and the engagement protrusion 80 moves in the circumferential direction, the engagement protrusion 80 moves along the first driven cam groove 86 and the second driven cam groove 86. The first driven cam 49 a and the second driven cam 50 a are axially displaced (advance and retreat) so as to move inside the cam groove 92 . Here, since the first driven cam groove 86 and the second driven cam groove 92 have opening shapes that are symmetrical with respect to the axial direction, the first driven cam groove 86 and the second driven cam groove 92 rotate as the driving cam 48a rotates. The driven cam 50a displaces (advances and retreats) in opposite directions with respect to the axial direction.

In the power transmission path switching device 5a of this example, as in the power transmission path switching device 5 of the first example of the embodiment, the drive cam 48a is rotationally driven by the electric actuator 56, and the first driven cam 49a and the second driven cam 49a are rotated. The connection/disengagement state of the first friction engagement device 40 and the second friction engagement device 41 is switched based on the axial displacement of the driven cam 50a. That is, the power transmission path switching device 5a has a first mode in which the first frictional engagement device 40 is connected and the second frictional engagement device 41 is disconnected, and a first mode in which the first frictional engagement device 40 is disconnected, Also, the second mode in which the second friction engagement device 41 is connected is switched.

<First Mode>
In order to switch the power transmission path switching device 5a to the first mode, the driving cam 48a is rotationally driven by the electric actuator 56 to displace (move) the engaging convex portion 80 to one side in the circumferential direction. moves in the direction in which the axial distance from the drive cam 48a widens (the other side in the axial direction), and the second driven cam 50a moves in the direction in which the axial distance from the drive cam 48a narrows (on the other side in the axial direction). ) move to one side in the axial direction. As a result, as shown in FIG. 10(A), the engaging convex portion 80 is located between the linear portion 90a arranged on one side in the axial direction of the first driven cam groove 86 and the second driven cam groove 92. Of these, it engages with the linear portion 96a arranged on the other side in the axial direction. In other words, when the engaging protrusion 80 is displaced to one side in the circumferential direction, the engagement between the engaging protrusion 80 and the first driven cam groove 86 causes the first driven cam 49a to move in the other axial direction. The first driven cam 49a moves (is guided) toward the side, and the first driven cam 49a moves toward one side in the axial direction ( guided).

When the first driven cam 49a is displaced toward the other side in the axial direction, the first friction plate 66 and the first separate plate 67 are pressed against each other, and the first friction engagement device 40 is connected. At the same time, when the second driven cam 50a is displaced toward one side in the axial direction, the force with which the second friction plate 72 and the second separate plate 73 press against each other is released, and the second friction engagement device 41 is disconnected. be done.

<Second mode>
In order to switch the power transmission path switching device 5a to the second mode, the driving cam 48a is rotationally driven by the electric actuator 56 to displace (move) the engaging convex portion 80 to the other side in the circumferential direction. 49a moves in a direction (on one side in the axial direction) in which the axial distance from the drive cam 48a decreases, and the second driven cam 50a moves in a direction (on one side in the axial direction) in which the distance from the drive cam 48a in the axial direction increases. ) move to one side in the axial direction. As a result, as shown in FIG. 10(B), the engaging convex portion 80 is aligned with the linear portion 90b arranged on the other side in the axial direction of the first driven cam groove 86 and the second driven cam groove 92. As shown in FIG. Among them, the linear portion 96b arranged on one side in the axial direction is engaged. In other words, when the engaging protrusion 80 is displaced to the other side in the circumferential direction, the engagement between the engaging protrusion 80 and the first driven cam groove 86 causes the first driven cam 49a to move axially. The second driven cam 50a moves (is guided) to one side, and the second driven cam 50a moves axially to the other side as the engagement protrusion 80 and the second driven cam groove 92 are engaged with each other. (guided).

When the first driven cam 49a is displaced toward one side in the axial direction, the force with which the first friction plate 66 and the first separate plate 67 press against each other is released, and the first friction engagement device 40 is disconnected. At the same time, when the second driven cam 50a is displaced toward the other side in the axial direction, the second friction plate 72 and the second separate plate 73 are pressed against each other, and the second friction engagement device 41 is connected.

The two-speed transmission 1a of this example switches between the high speed mode in which the reduction ratio between the input member 2 and the output member 3 is small (the reduction ratio is 1) by switching the operation mode of the power transmission path switching device 5a. , and a low-speed mode having a larger reduction ratio than the high-speed mode. Specifically, by switching the power transmission path switching device 5a to the first mode in which the first frictional engagement device 40 is connected and the second frictional engagement device 41 is disconnected, the two-speed transmission 1a can be switched to high speed mode. On the other hand, by switching the power transmission path switching device 5a to the second mode in which the first frictional engagement device 40 is disconnected and the second frictional engagement device 41 is connected, the two-speed transmission 1a You can switch to low speed mode.

In the power transmission path switching device 5a of the present example, the transmission motor 58 of the electric actuator 56 is energized and the drive cam 48a is rotated via the worm 57, so that the first frictional engagement device 40 and the second frictional engagement device 40 are rotated. Switches the connecting/disconnecting state of the friction engagement device 41 . Therefore, like the power transmission path switching device 5 of the first embodiment, the power transmission path switching device 5a of this example also requires a hydraulic system for controlling friction engagement devices such as clutches and brakes. do not have.

Further, in this example, when the power transmission path switching device 5a is switched to the first mode, the engaging convex portion 80 is the straight portion 90a of the first driven cam groove 86 and the straight portion 90a of the second driven cam groove 92. It engages with the straight portion 96a. On the other hand, when the power transmission path switching device 5a is switched to the second mode, the engaging convex portion 80 is aligned with the straight portion 90b of the first driven cam groove 86 and the straight portion 96b of the second driven cam groove 92. to engage. Therefore, according to the power transmission path switching device 5a of this example, similarly to the power transmission path switching device 5 of the first example of the embodiment, after the mode switching is completed, the energization of the transmission motor 58 is stopped. Also, the connected state of the first frictional engagement device 40 or the connected state of the second frictional engagement device 41 can be maintained.

In this example, the first driven cam groove 86 is composed of a pair of linear portions 90a and an inclined portion 91, and the second driven cam groove 92 is composed of a pair of linear portions 96b and an inclined portion. It consists of 97 However, when implementing the power transmission path switching device of the second aspect of the present invention, it is possible to displace the first driven cam and the second driven cam in opposite directions with respect to the axial direction as the drive cam rotates. If possible, any shape can be adopted for the first driven cam groove and the second driven cam groove. Other configurations and effects are the same as those of the first embodiment.

[Third example of embodiment]
11 to 13B show a third example of the embodiment of the invention. This example is an example in which the power transmission path switching device of the first aspect of the present invention is applied to the two-speed transmission of the second aspect of the present invention. The two-speed transmission 1b of this embodiment includes an input member 2, an output member 3a supported coaxially with and relatively rotatable with the input member 2, and a power transmission direction between the input member 2 and the output member 3a. and a power transmission path switching device 5b for switching the power transmission path between the input member 2 and the output member 3a.

The output member 3a includes an output tubular portion 9 having a female spline portion 8 on its inner peripheral surface, and an output flange portion 10a bent radially outward from one axial end of the output tubular portion 9. , an outer diameter side tubular portion 98 that is bent toward one side in the axial direction from the radially outer end portion of the output flange portion 10a, and the entire circumference from the intermediate portion in the radial direction of the output flange portion 10a toward one side in the axial direction. and a protruding inner diameter side tubular portion 99 . The output member 3 a has an output side first female spline portion 100 on the inner peripheral surface of the inner diameter side tubular portion 99 and an output side second female spline portion 101 on the inner peripheral surface of the outer diameter side tubular portion 98 . have Further, the output member 3a has through holes 102a and 102b axially penetrating through the output flange portion 10a at a plurality of circumferential locations on each of the radially inner portion and the radially outer portion of the output flange portion 10a.

The planetary gear mechanism 4a includes a sun gear 11a, a ring gear 12a, a carrier 13a, and a plurality of pinion gears 14.

The sun gear 11a is connected to the input member 2 so as to rotate together therewith. In this example, the sun gear 11a includes a tubular portion 103 and a flange portion 17a bent radially outward from one end portion of the tubular portion 103 in the axial direction. The sun gear 11a further includes a sun-side male spline portion 18a on the outer peripheral surface of the cylindrical portion 103, and further includes a gear portion 19 on the outer peripheral surface of the flange portion 17a. The cylindrical portion 103 of the sun gear 11a is externally fitted to the input cylindrical portion 6 of the input member 2 by a structure capable of transmitting torque, such as spline engagement.

The ring gear 12a is supported around the sun gear 11a coaxially with the sun gear 11a and rotatable relative to the sun gear 11a. In this example, the ring gear 12a includes a small-diameter tubular portion 20a, a large-diameter tubular portion 21a arranged coaxially with the small-diameter tubular portion 20a around the small-diameter tubular portion 20a, and a ring gear on one side of the small-diameter tubular portion 20a in the axial direction. A ring portion 22a is provided that connects an end portion and an end portion on one side in the axial direction of the large-diameter cylindrical portion 21a. The ring gear 12a further includes a gear portion 24 on the inner peripheral surface of the large-diameter cylindrical portion 21a.

In this example, the ring gear 12a is non-rotatably fitted in a portion that does not rotate during use, such as a housing (not shown). That is, the ring gear 12a does not rotate (rotation is blocked) even during use.

In this example, radial needle bearings 104 are arranged between the inner peripheral surface of the small-diameter tubular portion 20a and the outer peripheral surface of the input tubular portion 6 of the input member 2, and are arranged on both sides of the small-diameter tubular portion 20a in the axial direction. Thrust needle bearings 105a and 105b are arranged between the end face and the other axial side surface of the input flange portion 7 of the input member 2 and one axial side surface of the flange portion 17a of the sun gear 11a. Thus, the input member 2 is supported on the inner diameter side of the ring gear 12a so as to be freely rotatable with respect to the ring gear 12a.

The carrier 13a is coaxially and rotatably supported with the sun gear 11a and the ring gear 12a. In this example, the carrier 13a has a pair of rims 25c and 25d, each of which is annular and spaced apart in the axial direction, and one of the pair of rims 25c and 25d that is aligned with each other. A column portion 26 spanned between a plurality of locations in the circumferential direction, and a rim portion 25c on the other side in the axial direction of the pair of rim portions 25c and 25d. and a tubular portion 27a protruding toward the side over the entire circumference.

The carrier 13a is provided with circular holes 28c penetrating in the axial direction at a plurality of locations in the circumferential direction of a portion of the rim portion 25c on the other side in the axial direction, which is located radially outside the tubular portion 27a. A carrier-side male spline portion 71 is provided on the outer peripheral surface of the shaped portion 27a. Further, the carrier 13a axially penetrates a portion of the rim portion 25d on one side in the axial direction of the pair of rim portions 25c and 25d that is aligned with the circular hole 28c of the rim portion 25c on the other side in the axial direction. 28 d of circular holes are provided.

Each of the pinion gears 14 has its axially opposite ends of the support shaft 30 fitted and fixed in the circular holes 28c and 28d of the carrier 13a, respectively, and a body portion 31 rotatably supported by the support shaft 30. A gear portion 33 provided on the outer peripheral surface is meshed with the gear portion 19 of the sun gear 11a and the gear portion 24 of the ring gear 12a.

The power transmission path switching device 5b includes a housing 38a that does not rotate during use, a cam device 39b, a first frictional engagement device 40a, and a second frictional engagement device 41a.

The housing 38a includes an inner diameter side tubular portion 42a, an outer diameter side tubular portion 43a, an end portion on the other axial side of the inner diameter side tubular portion 42a, and an end portion on the other axial side of the outer diameter side tubular portion 43a. and a ring-shaped side plate portion 44a connecting the . The housing 38a includes a fixed male spline portion 45a on the outer peripheral surface of the inner diameter side tubular portion 42a, and a fixed female spline portion 46a on the inner peripheral surface of the outer diameter side tubular portion 43a. In addition, the housing 38a further includes a through hole 47a on the other side in the axial direction of the outer diameter side tubular portion 43a.

The cam device 39a has a drive cam 48b, a first driven cam 49b and a second driven cam 50b.

The drive cam 48b has a circular ring shape, and is mounted on the outer peripheral surface of the inner diameter side cylindrical portion 42a of the housing 38a on the other side in the axial direction via an angular ball bearing 51a capable of supporting a radial load and a thrust load. , are rotatably supported and axially displaceable. In addition, the drive cam 48a has a first drive cam surface 52a formed by alternately arranging concave portions and convex portions in the circumferential direction on the radially inner portion of one axial side surface. has a second drive cam surface 53a in which concave portions and convex portions are alternately arranged in the circumferential direction.

The drive cam 48a is rotationally driven by an electric actuator 56a. That is, a worm gear portion 59a of a worm 57a is meshed with a portion of the wheel gear portion 55a provided on the outer peripheral surface of the drive cam 48a that is exposed from the through hole 47a of the housing 38a. The worm 57a is connected to the output shaft of the speed change motor 58a.

The first driven cam 49a is arranged to face the radially inner portion of the driving cam 48a in the axial direction, and has a concave portion in the portion of the other axial side surface facing the first driving cam surface 52a. It has a first driven cam surface 60a in which convex portions are alternately arranged in the circumferential direction.

The first driven cam 49a has a first driven side female spline portion 61a on its inner peripheral surface, and the first driven side female spline portion 61a is connected to the fixed side male spline portion 45 of the housing 38a. The spline engagement allows only axial displacement with respect to the housing 38a.

The second driven cam 50a is arranged to face the radially outer portion of the driving cam 48a in the axial direction, and has a concave portion in a portion of the other axial side surface facing the second driving cam surface 53a. It has a second driven cam surface 62a in which convex portions are alternately arranged in the circumferential direction.

The second driven cam 50a has a second driven side male spline portion 63a on its outer peripheral surface, and the second driven side male spline portion 63a is splined to the fixed side female spline portion 46a of the housing 38a. By engaging them, they are supported so that they can only be displaced in the axial direction with respect to the housing 38a.

The cam device 39a includes a plurality of first rolling elements 64a that are rotatably arranged between the first driving cam surface 52a and the first driven cam surface 60a, and a plurality of rolling elements 64a that are arranged between the second driving cam surface 53a and the first driven cam surface 60a. It further includes a plurality of second rolling elements 65a that are rotatably arranged between the two driven cam surfaces 62a.

The first frictional engagement device 40a has a plurality of first friction plates 66a and first separate plates 67a each having a substantially circular ring shape and alternately arranged in the axial direction. In this example, the first frictional engagement device 40a is disposed between the output member 3a and the sun gear 11a, which are rotating bodies, respectively, and the output member 3a and the sun gear 11a rotate integrally. , and functions as a clutch that switches between the state of relative rotation with each other.

Each of the first friction plates 66a has a female spline portion on its inner peripheral surface, and the female spline portion is spline-engaged with the sun-side male spline portion 18a of the sun gear 11a, so that the sun gear 11a is axially engaged with the sun gear 11a. It is supported to allow only directional displacement.

Among the first friction plates 66a, between the first friction plate 66a, which exists on the other side in the axial direction, and the first driven cam 49a, a first elastic member 69a and a thrust member are provided in order from the other side in the axial direction. A rolling bearing 70a is arranged. In addition, in this example, the first elastic member 69a is configured by a disc spring. Thrust rolling bearing 70a includes a pair of bearing rings 106a, 106b. Of the pair of bearing rings 106a and 106b, the bearing ring 106a on one side in the axial direction has a pressing pin portion 107a projecting from one side surface in the axial direction toward the one side in the axial direction. is inserted through the through hole 102a of the output member 3a, and the tip portion is opposed to the other axial side surface of the first friction plate 66a, which is located on the farthest other axial side.

Each of the first separate plates 67a has a male spline portion on its outer peripheral surface, and by spline-engaging the male spline portion with the output-side first female spline portion 100 of the output member 3a, the output member 3a is supported to allow only axial displacement with respect to

Of the first separate plates 67a, the first separate plate 67a that exists on one side in the axial direction is axially displaced by a retaining ring 68a that is engaged with the end of the inner diameter side cylindrical portion 99 of the output member 3a on one side in the axial direction. Displacement to one side is blocked.

The second friction engagement device 41a has a plurality of second friction plates 72a and a plurality of second separate plates 73a, each of which is substantially circular and alternately arranged in the axial direction. In this example, the second frictional engagement device 41a is disposed between the output member 3a and the carrier 13a, which are rotating bodies, respectively, and the output member 3a and the carrier 13a rotate integrally. , and functions as a clutch that switches between the state of relative rotation with each other.

Each of the second friction plates 72a has a female spline portion on its inner peripheral surface, and by spline-engaging the female spline portion with the carrier-side male spline portion 71 of the carrier 13a, the carrier 13a is axially rotated. It is supported to allow only directional displacement.

Among the second friction plates 72a, between the second friction plate 72a, which is located on the other side in the axial direction, and the second driven cam 50a, a second elastic member 75a and a thrust member are provided in order from the other side in the axial direction. A rolling bearing 70b is arranged. In addition, in this example, the second elastic member 75a is configured by a disc spring. Thrust rolling bearing 70b includes a pair of bearing rings 106c, 106d. Of the pair of bearing rings 106c and 106d, the bearing ring 106c on one side in the axial direction has a pressing pin portion 107b projecting from one side surface in the axial direction toward the one side in the axial direction. is inserted through the through hole 102b of the output member 3a, and the tip portion is opposed to the other axial side surface of the second friction plate 72a, which is located on the farthest other axial side.

Each of the second separate plates 73a has a male spline portion on its outer peripheral surface, and by spline-engaging the male spline portion with the output-side second female spline portion 101 of the output member 3a, the output member 3a is supported to allow only axial displacement with respect to

Of the second separate plates 73a, the second separate plate 73a, which is located on the farthest one side in the axial direction, is axially secured by a retaining ring 74a locked to one axial end portion of the outer diameter side cylindrical portion 98 of the output member 3a. Displacement in one direction is blocked.

The power transmission path switching device 5b of this example rotates the drive cam 48b by the electric actuator 56a, and displaces the first driven cam 49b and the second driven cam 50b in the axial direction. A first mode in which the frictional engagement device 40a is connected and the second frictional engagement device 41a is disconnected, and a mode in which the first frictional engagement device 40a is disconnected and the second frictional engagement device 41a is connected. and the second mode.

<First Mode>
In order to switch the power transmission path switching device 5b to the first mode, the drive cam 48b is rotationally driven by the electric actuator 56a, and the first driven cam 49b is moved in the direction in which the axial distance from the drive cam 48b increases. (one side in the axial direction), and the second driven cam 50b is displaced in the direction (other side in the axial direction) in which the axial distance from the drive cam 48b is reduced.

When the first driven cam 49b is displaced toward one side in the axial direction, the pressing pin portion 107a presses the first friction plate 66a located on the farthest other side in the axial direction toward one side in the axial direction. Based on this, the first frictional engagement device 40a is connected by the first friction plate 66a and the first separate plate 67a pressing against each other.

When the second driven cam 50b is displaced toward the other side in the axial direction, the force of pressing the second friction plate 72a and the second separate plate 73a against each other is released. As a result, the distance between the second friction plate 72a located on the other side in the axial direction and the second separate plate 73a located on the one side in the axial direction widens, thereby disconnecting the second friction engagement device 41b.

<Second mode>
In order to switch the power transmission path switching device 5b to the second mode, the drive cam 48b is rotationally driven by the electric actuator 56a, and the first driven cam 49b is moved in the direction in which the axial distance from the drive cam 48b is reduced. (the other side in the axial direction), and the second driven cam 50b is displaced in the direction (one side in the axial direction) in which the axial distance from the drive cam 48b increases.

When the first driven cam 49b is displaced toward the other side in the axial direction, the force of pressing the first friction plate 66a and the first separate plate 67a against each other is released. As a result, the distance between the first friction plate 66a located on the other side in the axial direction and the first separate plate 67a located on the one side in the axial direction widens, thereby disconnecting the first friction engagement device 40a.

When the second driven cam 50 is displaced toward one side in the axial direction, the pressing pin portion 107b presses the second friction plate 72a located on the farthest other side in the axial direction toward one side in the axial direction. Based on this, the second friction engagement device 41a is connected by pressing the second friction plate 72a and the second separate plate 73a against each other.

The two-speed transmission 1b of this example switches between the high-speed mode in which the reduction ratio between the input member 2 and the output member 3a is small (the reduction ratio is 1) by switching the operation mode of the power transmission path switching device 5b. , and a low-speed mode having a larger reduction ratio than the high-speed mode.

Specifically, by switching the power transmission path switching device 5b to the first mode in which the first frictional engagement device 40a is connected and the second frictional engagement device 41a is disconnected, the two-speed transmission 1b can be switched to high speed mode. In this high-speed mode, the output member 3a and the sun gear 11a rotate integrally based on the connection of the first frictional engagement device 40a, and the second frictional engagement device 41a is disconnected. Based on this, the output member 3a and the carrier 13a are relatively rotatable. In such a high speed mode, the power of the input member 2 is transmitted to the output member 3a through the route shown in (C) below.
(C) Input member 2 → sun gear 11a → output member 3a
Thus, in the high speed mode, the power of the input member 2 is transmitted to the output member 3a without being decelerated.

On the other hand, by switching the power transmission path switching device 5b to the second mode in which the first frictional engagement device 40a is disconnected and the second frictional engagement device 41a is connected, the two-speed transmission 1a You can switch to low speed mode. In this low-speed mode, the output member 3a and the sun gear 11a become rotatable relative to each other and the second frictional engagement device 41a is connected based on the disconnection of the first frictional engagement device 40a. , the output member 3a and the carrier 13a rotate integrally. In such a low speed mode, the power of the input member 2 is transmitted to the output member 3a through the path shown in (D) below.
(D) Input member 2→sun gear 11a→rotational motion of pinion gear 14→revolutional motion of pinion gear 14 based on engagement with ring gear 12a→carrier 13a→output member 3a
Thus, in the low speed mode, the power of the input member 2 is reduced by the planetary gear mechanism 4a and transmitted to the output member 3a.

In the power transmission path switching device 5b of this example, the first frictional engagement device 40a and the second frictional engagement device 40a are driven by energizing the speed change motor 58a of the electric actuator 56a to rotate the drive cam 48a via the worm 57a. Switches the connecting/disconnecting state of the friction engagement device 41a. Therefore, like the power transmission path switching device 5 of the first embodiment, the power transmission path switching device 5b of this example also requires a hydraulic system for controlling friction engagement devices such as clutches and brakes. do not have.

In the two-speed transmission 1b of this example, the planetary gear mechanism 4a is arranged around the input member 2, and the power transmission path switching device 5b is arranged around the output member 3a. When implementing the two-speed transmission of the second aspect, various configurations can be adopted without being limited to this. For example, the planetary gear mechanism can be arranged around the output member and the power transmission path switching device can be arranged around the input member. In this case, the shape of each part is appropriately changed according to the configuration. Other configurations and effects are the same as those of the first embodiment.

The first to third examples of the embodiment described above can be combined as appropriate and carried out as long as there is no contradiction. Specifically, for example, the cam device 39b in the power transmission path switching device 5b of the third example of the embodiment can be replaced with the cam device 39a of the second example of the embodiment.

The two-speed transmission of the present invention can be used by being incorporated in the rotation transmission mechanism of various rotating mechanical devices, not limited to the electric drive system of electric vehicles and hybrid vehicles. Further, the power transmission path switching device of the present invention can be used by being incorporated in a rotation transmission mechanism of various rotating mechanical devices, not limited to a two-speed transmission.

1, 1a, 1b two-speed transmission 2 input member 3, 3a output member 4, 4a planetary gear mechanism 5, 5a, 5b power transmission path switching device 6 input tubular portion 7 input flange portion 8 female spline portion 9 output tubular portion Part 10, 10a Output flange portion 11, 11a Sun gear 12, 12a Ring gear 13, 13a Carrier 14 Pinion gear 15 Small diameter tubular portion 16 Large diameter tubular portion 17, 17a Flange portion 18, 18a Sun side male spline portion 19 Gear portion 20 Small diameter tubular portion 21 large-diameter cylindrical portion 22 circular ring portion 23 ring-side male spline portion 24 gear portion 25a, 25b, 25c, 25d rim portion 26 column portion 27 cylindrical portion 28a, 28b, 28c, 28d circular hole 29 carrier-side female spline portion 30 Support shaft 31 Body portion 32 Radial needle bearing 33 Gear portion 34a, 34b Retaining ring 35 Spacer 36a, 36b Thrust bearing 37 Pressing plate 38 Housing 39, 39a, 39b Cam device 40, 40a First friction engagement device 41, 41a Second Friction engagement device 42 Inner diameter cylinder 43 Outer cylinder 44 Side plate 45 Fixed male spline 46 Fixed female spline 47 Through hole 48, 48a, 48b Drive cam 49, 49a, 49b First driven cam 50, 50a, 50b second driven cam 51, 51a angular ball bearing 52, 52a first driving cam surface 53, 53a second driving cam surface 54a, 54b flat surface portion 55, 55a wheel gear portion 56, 56a electric actuator 57, 57a Worm 58, 58a Transmission motor 59 Worm gear portion 60, 60a First driven cam surface 61, 61a First driven side female spline portion 62, 62a Second driven cam surface 63, 63a Second driven side male spline Part 64, 64a First rolling element 65, 65a Second rolling element 66, 66a First friction plate 67, 67a First separate plate 68, 68a Retaining ring 69, 69a First elastic member 70, 70a Thrust rolling bearing 71 Carrier side Male spline portion 72, 72a Second friction plate 73, 73a Second separate plate 74, 74a Retaining ring 75, 75a Second elastic member 76 Spacer 78 Radial needle bearing 79 Thrust needle bearing 80 Engagement convex portion 81 Side plate portion 82 Inner diameter side cylinder portion 83 Outer diameter side cylinder portion 84 Circular hole 85 Engagement pin 86 First driven cam groove 87 Side plate portion 88 Outer diameter side cylinder portion 89 Inner diameter side cylinder portion 90a, 90b Straight portion 91 Inclined portion 92 Second driven cam groove 93 Small diameter cylindrical portion 94 Large diameter cylindrical portion 95 Circular ring portions 96a, 96b Straight portion 97 Inclined portion 98 Outer diameter side cylindrical portion 99 Inner diameter side cylindrical portion 100 Output side first female Spline portion 101 Output-side second female spline portions 102a, 102b Through hole 103 Cylindrical portion 104 Radial needle bearings 105a, 105b Thrust needle bearings 106a, 106b, 106c, 106d Bearing rings 107a, 107b Pressing pin portion 108 First return spring 109 Second return spring

The present invention relates to a power transmission path switching device for switching a power transmission path between an input member and an output member.

In recent years, with the trend of reducing the consumption of fossil fuels, research into electric vehicles and hybrid vehicles has progressed and is being implemented in some areas. Electric motors, which are the power source of electric vehicles and hybrid vehicles, differ from internal combustion engines (engines) that work by directly burning fossil fuels. , the maximum torque is generated at start-up), it is not necessary to provide a transmission like a general automobile using an internal combustion engine as a drive source. However, even when an electric motor is used as a drive source, the acceleration performance and high-speed performance can be improved by providing a transmission. Specifically, by providing a transmission, the relationship between the running speed and acceleration of the vehicle is made smoother, closer to that of a vehicle equipped with a gasoline engine and a transmission provided in the power transmission system. can. This point will be described with reference to FIG.

For example, if a power transmission device with a large reduction ratio is placed between the output shaft of the electric motor and the input part of the differential gear connected to the drive wheels, the acceleration (G) and running speed (km/h) of the electric vehicle is as shown by the solid line a in FIG. That is, although the acceleration performance at low speed is excellent, high speed running becomes impossible. On the other hand, when a power transmission device with a small reduction ratio is arranged in the intermediate portion, the relationship becomes like the chain line b in FIG. In other words, high-speed running becomes possible, but the acceleration performance at low speeds is impaired. On the other hand, if a transmission is provided between the output shaft and the input portion, and the reduction ratio of this transmission is changed according to the vehicle speed, the portion of the solid line a to the left of the point P and the chain line It is possible to obtain a characteristic such that the portion on the right side of the point P in b is continuous. This characteristic is almost the same as that of a gasoline engine vehicle having a similar output, as indicated by the dashed line c in FIG. It can be seen that the same performance can be obtained.

Japanese Patent Application Laid-Open No. 5-116549 discloses that the torque of the output shaft of an electric motor is transmitted through a two-speed transmission that combines a pair of planetary gear mechanisms and a pair of brakes. and) a structure for an electric vehicle drive system that transmits to a differential gear is disclosed. In this electric vehicle driving device, the constituent elements of the pair of planetary gear mechanisms are switched between a rotatable state and a non-rotatable state based on switching the connection/disengagement state of the pair of brakes, whereby the electric motor The speed reduction ratio between the output shaft and the differential gear can be switched between two stages of high and low.

JP-A-5-116549

The device described in Japanese Patent Application Laid-Open No. 5-116549 includes friction engagement elements supported by components of a planetary gear mechanism and friction engagement elements supported by a housing by hydraulically operated servo pistons PL and PH. are pressed together to connect (engage) the brakes. However, in electric vehicles and hybrid vehicles, in order to reduce costs and improve power consumption performance by simplifying the system, it is possible to switch the reduction ratio of the two-speed transmission with an electric actuator and eliminate the need for a hydraulic system. desired.

SUMMARY OF THE INVENTION It is an object of the present invention to realize a structure of a power transmission path switching device capable of switching a power transmission path by an electric actuator.

The power transmission path switching device of the present invention includes:
a drive cam supported rotatably and not displaceable in the axial direction; a cam device having a first driven cam and a second driven cam axially displaced out of phase;
a first frictional engagement device having at least one first friction plate and at least one first separate plate supported so as to be axially displaceable relative to each other;
a second frictional engagement device having at least one second friction plate and at least one second separate plate supported so as to be axially displaceable relative to each other;
Prepare.

In particular, in the power transmission path switching device of the present invention,
As the drive cam rotates,
The first frictional engagement is achieved by pressing the first friction plate and the first separate plate against each other based on displacing the first driven cam in a direction to widen the axial distance from the driving cam. When the device is connected and the second driven cam is displaced in the direction in which the axial distance from the driving cam is reduced, the force for pressing the second friction plate and the second separate plate against each other is reduced. a first mode in which release disconnects the second frictional engagement device;
By displacing the first driven cam in a direction in which the distance between the first driven cam and the drive cam in the axial direction is reduced, the force that presses the first friction plate and the first separate plate against each other is released, whereby the first (1) Disconnecting the frictional engagement device and displacing the second driven cam in a direction to widen the axial distance from the driving cam causes the second friction plate and the second separate plate to move toward each other. a second mode in which the second friction engagement device is connected by pressing together;
is switched.

The power transmission path switching device of the present invention includes:
The first driven cam is disposed between the first driven cam and the first frictional engagement device, and elastically biases the first driven cam and the first frictional engagement device away from each other. 1 elastic member;
A second driven cam is disposed between the second driven cam and the second frictional engagement device, and elastically biases the second driven cam and the second frictional engagement device away from each other. 2 elastic members;
can be further provided.

Further, the power transmission path switching device of the present invention is
The drive cam has a first drive cam surface and a second drive cam surface formed by arranging concave portions and convex portions on the axial side surface with the same cycle and different phases in the circumferential direction, and
The first driven cam has a first driven cam surface on an axial side surface facing the first driving cam surface,
The second driven cam has a second driven cam surface on an axial side surface facing the second driving cam surface, and
The cam device includes a plurality of first rolling elements arranged between the first driving cam surface and the first driven cam surface, and the second driving cam surface and the second driven cam surface. It further comprises a plurality of second rolling elements arranged between.
In particular, in the power transmission path switching device of the present invention, the first drive cam surface and the second drive cam surface are provided on the side surface of the drive cam on the same side in the axial direction.

Although it is outside the technical scope of the present invention,
The drive cam may have at least one, preferably a plurality of engagement projections protruding in the radial direction,
The first driven cam is formed to extend in the circumferential direction and has at least one, preferably a plurality of, first driven cam grooves with which the engaging protrusions are engaged. 1. The driven cam groove can have an inclined portion inclined with respect to the circumferential direction at least in part, and
The second driven cam is formed to extend in the circumferential direction and has at least one, preferably a plurality of second driven cam grooves with which the engaging projections engage, The second driven cam groove can have an opening shape symmetrical with the first driven cam with respect to the axial direction.

A plurality of each of the first friction plates and the first separate plates can be provided, and the first friction plates and the first separate plates can be alternately arranged. A plurality of each of the second friction plates and the second separate plates can be provided, and the second friction plates and the second separate plates can be alternately arranged.

The first friction engagement device may further include a first return spring that elastically biases the first friction plate and the first separate plate in a direction to separate them from each other. The second friction engagement device may further include a second return spring that elastically biases the second friction plate and the second separate plate in a direction to separate them from each other.

The two-speed transmission of another invention is
an input member;
an output member arranged coaxially with the input member;
a planetary gear mechanism disposed between the input member and the output member with respect to the power transmission direction;
The planetary gear mechanism includes a sun gear, a ring gear arranged coaxially with the sun gear around the sun gear, a carrier arranged coaxially with the sun gear, the sun gear and the ring gear meshing with each other, and the carrier and a plurality of pinion gears supported so as to freely rotate around their own central axis,
A power transmission path switching device for switching a power transmission path between the input member and the output member is further provided.

In a two-speed transmission of another invention , the power transmission path switching device is the power transmission path switching device of the present invention, and the power transmission path switching device further includes an electric actuator that rotationally drives the drive cam. .

The drive cam may have a wheel gear portion on its outer peripheral surface, and the electric actuator may include a worm that meshes with the wheel gear portion, and a speed change motor that rotationally drives the worm.

A two-speed transmission according to a first aspect of another invention comprises:
the input member is connected to the sun gear so as to rotate integrally with the sun gear;
the output member is connected to the carrier so as to rotate integrally therewith;
one of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the sun gear or the input member but not rotatable;
the other of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the carrier or the output member, but unrotatable;
one of the second friction plate and the second separate plate is supported so as to be axially displaceable relative to a portion, such as a housing, which does not rotate during use, but not to rotate, and ,
The other of the second friction plate and the second separate plate is supported so as to be axially displaceable relative to the ring gear and unrotatable.

A two-speed transmission according to a second aspect of another invention ,
the input member is connected to the sun gear so as to rotate integrally with the sun gear;
The ring gear is supported and fixed to a portion such as a housing that does not rotate during use,
one of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the sun gear or the input member but not rotatable;
the other of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the output member and unrotatable;
one of the second friction plate and the second separate plate is supported so as to be axially displaceable relative to the carrier and unrotatable;
And, the other of the second friction plate and the second separate plate is supported so as to be axially displaceable relative to the output member and unrotatable.

In the power transmission path switching device of the present invention, the connection/disengagement states of the first friction engagement device and the second friction engagement device are switched based on rotation of the drive cam, and the drive cam operates the electric motor and the like. It can be rotationally driven by an electric actuator included. In short, according to the power transmission path switching device of the present invention, the power transmission path can be switched by the electric actuator. Further, according to the two-speed transmission of another invention provided with the power transmission path switching device of the invention, the electric actuator can switch the speed reduction ratio between the input member and the output member in two stages of high and low.

FIG. 1 is a cross-sectional view showing a two-speed transmission of a first embodiment of the invention. FIG. 2 is a schematic diagram showing a two-speed transmission of the first example of the embodiment of the invention. FIG. 3A is a schematic diagram showing a power transmission path in high speed mode, and FIG. 3B is a schematic diagram showing a power transmission path in low speed mode. FIG. 4 is a cross-sectional view showing a power transmission path switching device taken out in the first embodiment of the present invention. FIG. 5 is an exploded perspective view showing the cam device and the electric actuator in the first embodiment of the present invention. FIG. 6 is a diagram for explaining the phase relationship in the circumferential direction between the first driving cam surface and the second driving cam surface. FIG. 7A is a cross-sectional view showing the first frictional engagement device, and FIG. 7B is a cross-sectional view showing the second frictional engagement device. FIG. 8 is a cross-sectional view showing a two-speed transmission of the first example of the reference example . FIG. 9 is a perspective view showing a second example of the first example of the reference example with the cam device and the electric actuator taken out and disassembled. FIG. 10(A) is a diagram showing the state of engagement between the engagement protrusions and the first driven cam groove and the second driven cam groove in high speed mode, and FIG. 10(B) is a diagram in low speed mode. is a diagram showing the state of engagement between the engagement convex portion of No. 1 and the first driven cam groove and the second driven cam groove. FIG. 11 is a cross-sectional view showing a two-speed transmission according to a second embodiment of the invention. FIG. 12 is a schematic diagram showing a two-speed transmission of a second example of the embodiment of the invention. FIG. 13A is a schematic diagram showing a power transmission path in high speed mode, and FIG. 13B is a schematic diagram showing a power transmission path in low speed mode. FIG. 14 is a diagram for explaining the effect of incorporating a transmission into a drive device using an electric motor as a drive source.

[First example of embodiment]
1 to 7 show a first example of an embodiment of the invention. This example is an example in which the power transmission path switching device of the present invention is applied to a two-speed transmission of the first aspect of another invention. The two-speed transmission 1 of this example is arranged, for example, between the output shaft of an electric motor, which is the power source of an electric vehicle or a hybrid vehicle, and a differential gear, and increases the torque of the output shaft of the electric motor. After (deceleration), or without increasing (deceleration), it is transmitted to the differential gear as it is. The two-speed transmission of this example includes an input member 2, an output member 3, a planetary gear mechanism 4, and a power transmission path switching device 5, and a reduction ratio between the input member 2 and the output member 3 can be switched between high and low levels.

The input member 2 is connected to a drive shaft (not shown) such as an output shaft of an electric motor, and receives torque (power). In this example, the input member 2 includes an input tubular portion 6 and an input flange portion bent radially outward from one axial end (right side in FIGS. 1 to 4) of the input tubular portion 6. 7. The drive shaft is, for example, fitted inside the inner peripheral surface of the input tubular portion 6 so as to transmit torque, or coupled to the input flange portion 7 by bolting or the like so as to be able to transmit torque.

The output member 3 is arranged coaxially with the input member 2, is connected to a driven shaft (not shown) such as a differential gear or a propeller shaft, and outputs torque to the driven shaft. In this example, the output member 3 includes an output tubular portion 9 having a female spline portion 8 on its inner peripheral surface, and an end portion on the other axial side (left side in FIGS. 1 to 4) of the output tubular portion 9. and an output flange portion 10 that is bent radially outward. The driven shaft is connected to the output member 3 so as to transmit torque by spline-engaging the male spline portion provided on the outer peripheral surface of the distal end portion with the female spline portion 8 of the output tubular portion 9 .

The planetary gear mechanism 4 is arranged between the input member 2 and the output member 3 with respect to the power transmission direction, and includes a sun gear 11 , a ring gear 12 , a carrier 13 and a plurality of pinion gears 14 .

The sun gear 11 is connected to the input member 2 so as to rotate together therewith. In this example, the sun gear 11 includes a small-diameter cylindrical portion 15 on one side in the axial direction, a large-diameter cylindrical portion 16 on the other side in the axial direction, and an end portion of the large-diameter cylindrical portion 16 on the other side in the axial direction that is bent radially outward. and a flange portion 17 . The sun gear 11 includes a sun-side male spline portion 18 on the outer peripheral surface of the large-diameter cylindrical portion 16 and a gear portion 19 that is a spur gear or a helical gear on the outer peripheral surface of the flange portion 17 . The sun gear 11 has a small-diameter cylindrical portion 15 externally fitted to the input cylindrical portion 6 of the input member 2 by a structure capable of transmitting torque, such as spline engagement.

The ring gear 12 is supported around the sun gear 11 coaxially with the sun gear 11 and rotatable relative to the sun gear 11 . In this example, the ring gear 12 includes a small-diameter cylindrical portion 20 on one side in the axial direction, a large-diameter cylindrical portion 21 on the other side in the axial direction, an end portion of the small-diameter cylindrical portion 20 on the other side in the axial direction, and the large-diameter cylindrical portion 21 . and a circular ring portion 22 that connects the end portion on one side in the axial direction of the . The ring gear 12 has a ring-side male spline portion 23 on the outer peripheral surface of the small-diameter cylindrical portion 20 and a gear portion 24 that is a spur gear or a helical gear on the inner peripheral surface of the large-diameter cylindrical portion 21 .

The carrier 13 is coaxially supported by the sun gear 11 and the ring gear 12 and connected to the output member 3 so as to rotate integrally with the output member 3 . In this example, the carrier 13 comprises a pair of rims 25a, 25b, each of which is annular and spaced apart in the axial direction, and one of the pair of rims 25a, 25b that is aligned with each other. A column portion 26 (see FIG. 11 to be described later) that spans between a plurality of locations in the circumferential direction, and the radial direction of one side surface of the rim portion 25a on one side in the axial direction of the pair of rim portions 25a and 25b. A cylindrical portion 27 protrudes from the intermediate portion toward one side in the axial direction over the entire circumference.

The carrier 13 is provided with circular holes 28a penetrating in the axial direction at a plurality of locations in the circumferential direction of a portion of the rim portion 25a on one side in the axial direction, which is located radially outside the tubular portion 27, and has a tubular shape. A carrier-side female spline portion 29 is provided on the inner peripheral surface of the portion 27 . Further, the carrier 13 axially penetrates a portion of the rim portion 25b on the other side in the axial direction of the pair of rim portions 25a and 25b that is aligned with the circular hole 28a of the rim portion 25a on the one side in the axial direction. It has a circular hole 28b for The carrier 13 rotates integrally with the output member 3 by connecting the rim portion 25b on the other side in the axial direction to the output flange portion 10 of the output member 3 by a structure capable of transmitting torque such as spline engagement. is configured to

Each pinion gear 14 meshes with the sun gear 11 and the ring gear 12, and is supported by the carrier 13 so as to be freely rotatable about its central axis. In this example, each of the pinion gears 14 has a cylindrical body portion 31 rotatably supported by a radial needle bearing 32 around a cylindrical support shaft 30 in an axially intermediate portion. The main body portion 31 has a gear portion 33 which is a spur gear or a helical gear and meshes with the gear portion 19 of the sun gear 11 and the gear portion 24 of the ring gear 12 on its outer peripheral surface. The support shaft 30 has both ends in the axial direction fitted and fixed to the circular holes 28 a and 28 b of the carrier 13 .

In this example, the other axial side surface of the spacer 35, whose displacement to one side in the axial direction is prevented by the retaining ring 34a engaged with the axially intermediate portion of the large-diameter cylindrical portion 16 of the sun gear 11, is abutted against one axial side surface of the radially inner portion of the rim portion 25a via a thrust bearing 36a. Further, a retaining ring 34b engaged with the end portion of the large-diameter cylindrical portion 21 of the ring gear 12 on the other axial side prevents displacement to the other axial side of the pressing plate 37, and the axial piece of the radially inner portion of the holding plate 37 The side surface abuts against the other axial side surface of the radially inner portion of the rim portion 25b (the output flange portion 10 of the output member 3) on the other axial side via the thrust bearing 36b. Accordingly, separation of the sun gear 11, the ring gear 12, the carrier 13, and the pinion gear 14 can be prevented when the planetary gear mechanism 4 is assembled. In short, the planetary gear mechanism 4 can be handled integrally as a subassembly.

The power transmission path switching device 5 switches the power transmission path between the input member 2 and the output member 3 . The power transmission path switching device 5 of this example includes a housing 38 that does not rotate during use, a cam device 39 , a first frictional engagement device 40 and a second frictional engagement device 41 .

The housing 38 connects the inner diameter side tubular portion 42, the outer diameter side tubular portion 43, one axial end portion of the inner diameter side tubular portion 42, and one axial end portion of the outer diameter side tubular portion 43. A ring-shaped side plate portion 44 is provided. The housing 38 includes a fixed-side male spline portion 45 on the outer peripheral surface of the inner diameter-side tubular portion 42 and a fixed-side female spline portion 46 on the inner peripheral surface of the outer diameter-side tubular portion 43 . In addition, the housing 38 further includes a through hole 47 that penetrates in the radial direction and extends in the circumferential direction on one axial side portion of the outer diameter side tubular portion 43 .

In this example, a radial needle bearing 78 is arranged between the inner peripheral surface of the inner cylindrical portion 42 of the housing 38 and the outer peripheral surface of the input cylindrical portion 6 of the input member 2, and the axial direction of the side plate portion 44 is arranged. By disposing a thrust needle bearing 79 between one side surface and the other axial side surface of the input flange portion 7 , the input member 2 is rotatably supported with respect to the housing 38 .

The cam device 39 includes a drive cam 48 that is rotatably supported so as not to be displaced in the axial direction, and a cam device 39 that is supported so as to be rotatable and axially displaced relative to the drive cam 48, and is rotatable with respect to the rotation of the drive cam 48. Along with this, it is provided with a first driven cam 49 and a second driven cam 50 that are axially displaced in phases different from each other. It should be noted that the displacement in the axial direction with mutually different phases means that the first driven cam 49 and the second driven cam 50 move in opposite directions in the axial direction as the drive cam 48 rotates, as will be described later. It means to displace (advance and retreat). That is, when the first driven cam 49 moves toward one side in the axial direction, the second driven cam 50 moves toward the other side in the axial direction. When moving toward the other side, the second driven cam 50 moves toward one side in the axial direction.

The drive cam 48 has a circular ring shape, and is mounted on the outer peripheral surface of one end in the axial direction of the inner diameter side cylindrical portion 42 of the housing 38 via an angular ball bearing 51 capable of supporting a radial load and a thrust load. It is rotatably supported and axially displaceable.

The driving cam 48 has a first driving cam surface 52 and a second driving cam, which are formed by arranging concave portions and convex portions on the other side surface in the axial direction with the same cycle and different phases (opposite phases) with respect to the circumferential direction. It has a face 53 . That is, the drive cam 48 has a first drive cam surface 52 on the radially inner portion of the other axial side surface, and a second drive cam surface 53 on the radially outer portion of the other axial side surface. In this example, each of the first driving cam surface 52 and the second driving cam surface 53 has the same number of concave portions and convex portions (three each in the illustrated example) alternately in the circumferential direction and The directional phases are shifted by half a period (60 degrees in the illustrated example) (in opposite phases). That is, as shown in FIG. 6, in the circumferential direction, the convex portion of the first drive cam surface 52 is in phase with the concave portion of the second drive cam surface 53 in phase. The concave portion of the driving cam surface 52 is in phase with the convex portion of the second driving cam surface 53 in phase. The first drive cam surface 52 has a flat surface portion 54a perpendicular to the central axis of the drive cam 48 on the tip end surface of the projection, and the second drive cam surface 53 has a flat surface portion 54a on the tip end surface of the projection. It has a flat surface portion 54b perpendicular to the central axis of the drive cam 48 . It should be noted that each of the first drive cam surface 52 and the second drive cam surface 53 is not limited to a shape symmetrical with respect to the circumferential direction as shown in FIG. 6, and various shapes can be adopted.

The drive cam 48 further has a wheel gear portion 55, which is a helical gear having a helical tooth trace, on the outer peripheral surface.

The drive cam 48 is rotationally driven by an electric actuator 56 . The electric actuator 56 includes a worm 57 and a speed change motor 58 . The worm 57 has a worm gear portion 59 that meshes with the portion of the wheel gear portion 55 of the drive cam 48 that is exposed from the through hole 47 of the housing 38 on the outer peripheral surface of the axially intermediate portion. The speed change motor 58 drives the worm 57 to rotate. That is, the drive cam 48 is rotationally driven by the transmission motor 58 via a worm speed reducer formed by meshing the wheel gear portion 55 and the worm gear portion 59 .

The first driven cam 49 is arranged to face the radially inner portion of the drive cam 48 in the axial direction. The first driven cam 49 has the same number of recesses and projections as the number of recesses and projections of the first drive cam surface 52 on one side surface of the drive cam 48 in the axial direction facing the first drive cam surface 52 (this is the same number). three in the example) have first driven cam surfaces 60 that alternate in the circumferential direction. However, the first driven cam surface 60 facing the first driving cam surface 52 can also be configured by a flat surface orthogonal to the central axis.

The first driven cam 49 has a first driven side female spline portion 61 on its inner peripheral surface, and the first driven side female spline portion 61 is connected to the fixed side male spline portion 45 of the housing 38 . Due to the spline engagement, it is supported with respect to the housing 38 so that it can only be displaced in the axial direction.

The second driven cam 50 is arranged axially facing the radially outer portion of the driving cam 48 . The second driven cam 50 has the same number of recesses and projections as the number of recesses and projections of the second drive cam surface 53 on one side surface of the drive cam 48 in the axial direction facing the second drive cam surface 53 (this is the same number). three in the example) have second driven cam surfaces 62 that alternate in the circumferential direction. However, the second driven cam surface 62 facing the second driving cam surface 53 can also be configured by a flat surface perpendicular to the central axis.

The second driven cam 50 has a second driven side male spline portion 63 on its outer peripheral surface, and the second driven side male spline portion 63 is splined to the fixed side female spline portion 46 of the housing 38 . By engaging them, they are supported so that they can only be displaced in the axial direction with respect to the housing 38 .

The cam device 39 of this example includes a plurality of first rolling elements 64 rotatably arranged between the first driving cam surface 52 and the first driven cam surface 60, and a second driving cam surface. Between 53 and the second driven cam surface 62, there are further provided a plurality of second rolling elements 65 that are rollably arranged. That is, in this example, as the driving cam 48 rotates, the first rolling element 64 rides on the bottom of the concave portion of the first driving cam surface 52 and the distance from the bottom of the concave portion of the first driven cam surface 60 increases. As the riding amount increases or decreases, the first driven cam 49 is displaced in the axial direction, and the amount of riding of the second rolling element 65 from the bottom of the concave portion of the second driving cam surface 53 and the second driven cam surface increase or decrease. The second driven cam 50 is displaced in the axial direction by increasing or decreasing the riding amount from the bottom of the recess 62 . Although balls are used as the first rolling elements 64 and the second rolling elements 65 in this example, rollers can also be used as the first rolling elements and the second rolling elements.

In this example, each of the first driving cam surface 52 and the second driving cam surface 53 of the driving cam 48 has the same number of concave portions and convex portions, alternately in the circumferential direction, and half in phase in the circumferential direction. They are arranged with a period shift (in opposite phase). Therefore, as the drive cam 48 rotates, the first driven cam 49 and the second driven cam 50 are displaced (advance and retreat) in opposite directions with respect to the axial direction. Specifically, when the first driven cam 49 moves toward one side in the axial direction, the second driven cam 50 moves toward the other side in the axial direction, whereas the first driven cam 49 moves toward the other side in the axial direction. moves toward the other side in the axial direction, the second driven cam 50 moves toward the one side in the axial direction.

The first friction engagement device 40 has a plurality of first friction plates 66 and first separate plates 67 . The first friction plates 66 and the first separate plates 67 each have a substantially ring shape and are alternately arranged in the axial direction. In this example, the first frictional engagement device 40 is disposed between the sun gear 11 and the carrier 13, and the sun gear 11 and the carrier 13, which are rotating bodies, rotate integrally and mutually. It functions as a clutch that switches between the state of relative rotation.

Each of the first friction plates 66 has a female spline portion on its inner peripheral surface, and the female spline portion is spline-engaged with the sun-side male spline portion 18 of the sun gear 11 so that the sun gear 11 is axially engaged with the sun gear 11 . It is supported to allow only directional displacement.

Each of the first separate plates 67 has a male spline portion on its outer peripheral surface, and the male spline portion is spline-engaged with the carrier-side female spline portion 29 of the carrier 13 , thereby axially moving the carrier 13 . Only the displacement of the support is possible.

Of the first separate plates 67 , the first separate plate 67 that exists on the other side in the axial direction is axially disengaged by a retaining ring 68 that is engaged with the end portion on the other side in the axial direction of the cylindrical portion 27 of the carrier 13 . Displacement to the other side is blocked.

Among the first separate plates 67, between the first separate plate 67 existing on one side in the axial direction and the first driven cam 49, in order from one side in the axial direction, a first elastic member 69 and a thrust rolling bearing are provided. 70 are sandwiched. The first elastic member 69 elastically urges the first friction engagement device 40 and the first driven cam 49 in directions away from each other in the axial direction. In addition, in this example, the first elastic member 69 is configured by a disc spring. However, the first elastic member 69 can also be configured by a torsion coil spring or the like.

The first friction engagement device 40 separates the first friction plate 66 and the first separate plate 67 from each other, and is elastic in the direction of releasing the force of pressing the first friction plate 66 and the first separate plate 67 against each other. A positively biasing first return spring 108 is further provided. In this example, as shown in FIG. 7A, the first return spring 108 is arranged between the first separate plate 67 located on one side in the axial direction and the first separate plate 67 located on the other side in the axial direction. It spans between them and elastically urges the first separate plate 67 on one side in the axial direction and the first separate plate 67 on the other side in the axial direction to move away from each other.

The second friction engagement device 41 has a plurality of second friction plates 72 and second separate plates 73 . The second friction plates 72 and the second separate plates 73 are each substantially annular and arranged alternately in the axial direction. In this example, the second friction engagement device 41 is arranged between the ring gear 12 and the housing 38 and functions as a brake that switches between a state in which the ring gear 12 is allowed to rotate and a state in which it is blocked.

Each of the second friction plates 72 has a female spline portion on its inner peripheral surface, and by spline-engaging the female spline portion with the ring-side male spline portion 23 of the ring gear 12 , the ring gear 12 is axially rotated. It is supported to allow only directional displacement.

Each of the second separate plates 73 has a male spline portion on its outer peripheral surface, and by spline-engaging the male spline portion with the fixed-side female spline portion 46 of the housing 38 , it is axially moved relative to the housing 38 . Only the displacement of the support is possible.

Of the second separate plates 73 , the second separate plate 73 that exists on the other side in the axial direction is secured by a snap ring 74 that is engaged with the end portion on the other side in the axial direction of the outer diameter side tubular portion 43 of the housing 38 . Displacement to the other side in the axial direction is prevented.

Among the second separate plates 73, between the second separate plate 73 that exists on one side in the axial direction and the second driven cam 50, a second elastic member 75 and a substantially L-shaped and a spacer 76 having a cross-sectional shape of . The second elastic member 75 elastically urges the second friction engagement device 41 and the second driven cam 50 in directions away from each other in the axial direction. In addition, in this example, the second elastic member 75 is configured by a disc spring. However, the second elastic member 75 can also be configured by a torsion coil spring or the like.

The second friction engagement device 41 separates the second friction plate 72 and the second separate plate 73 from each other, and releases the force of the second friction plate 72 and the second separate plate 73 pressing against each other. It further comprises a second return spring 109 that is elastically biased. In this example, as shown in FIG. 7(B), the second return spring 109 is arranged between the second separate plate 73 located on one side in the axial direction and the second separate plate 73 located on the other side in the axial direction. It spans between them and elastically urges the second separate plate 73 present on one side in the axial direction and the second separate plate 73 present on the othermost side in the axial direction in a direction away from each other.

The power transmission path switching device 5 rotationally drives the driving cam 48 by the electric actuator 56, and displaces the first driven cam 49 and the second driven cam 50 in the axial direction to achieve the first frictional engagement. The connection/disconnection state between the device 40 and the second friction engagement device 41 is switched. Specifically, the power transmission path switching device 5 of this example has a first mode in which the first frictional engagement device 40 is connected and the second frictional engagement device 41 is disconnected, and a first mode in which the first frictional engagement device 41 is disconnected. Switching to the second mode in which the device 40 is disconnected and the second friction engagement device 41 is connected. Each case will be described below.

<First mode>
In order to switch the power transmission path switching device 5 to the first mode, the drive cam 48 is rotationally driven by the electric actuator 56, and the first drive cam surface of the first rolling element 64 is moved as indicated by the two-dot chain line in FIG. By increasing the amount by which the first driven cam surface 60 rides over the bottom of the concave portion 52 and the amount by which the first driven cam surface 60 rides over the bottom portion of the concave portion, the first driven cam 49 is moved in the direction in which the axial distance from the driving cam 48 increases ( and the amount by which the second rolling element 65 rides over the bottom of the recess of the second driving cam surface 53 and the amount of running over the bottom of the recess of the second driven cam surface 62 is determined by By decreasing, the second driven cam 50 is displaced in a direction (one side in the axial direction) in which the axial distance from the drive cam 48 is reduced. In this example, when the power transmission path switching device 5 is switched to the first mode (switching to the first mode is completed), the first rolling element 64 moves toward the flat surface portion of the first drive cam surface 52. It runs on 54a.

When the first driven cam 49 is displaced toward one side in the axial direction, the first separate plate 67 located on the farthest one side in the axial direction moves toward the other side in the axial direction via the first elastic member 69 and the thrust rolling bearing 70 . pressed. Based on this, the first friction plate 66 and the first separate plate 67 are pressed against each other, thereby connecting the first friction engagement device 40 .

On the other hand, when the second driven cam 50 is displaced toward one side in the axial direction, the force with which the second friction plate 72 and the second separate plate 73 press each other is released. As a result, due to the action of the second return spring 109, the distance between the second separate plate 73 located on one side in the axial direction and the second separate plate 73 located on the other side in the axial direction widens, thereby increasing the second friction. The engagement device 41 is disconnected.

<Second mode>
In order to switch the power transmission path switching device 5 to the second mode, the drive cam 48 is rotationally driven by the electric actuator 56, and the first drive cam surface 52 of the first rolling element 64 is rotated as indicated by the dashed line in FIG. By reducing the amount by which the first driven cam surface 60 rides over the bottom of the recess and the amount by which the first driven cam surface 60 rides over the bottom of the recess, the first driven cam 49 is moved in the direction in which the axial distance from the drive cam 48 decreases (axis direction one side), and increase the amount of the second rolling element 65 riding over the bottom of the recess of the second drive cam surface 53 and the amount of riding over the bottom of the recess of the second driven cam surface 62. As a result, the second driven cam 50 is displaced in the direction in which the axial distance from the drive cam 48 increases (the other side in the axial direction). In this example, when the power transmission path switching device 5 is switched to the second mode (switching to the second mode is completed), the second rolling element 65 moves toward the flat surface portion of the second drive cam surface 53. It runs on 54b.

The first driven cam 49 is displaced toward one side in the axial direction, and the force of pressing the first friction plate 66 and the first separate plate 67 against each other is released. As a result, due to the action of the first return spring 108, the distance between the first separate plate 67 located on one side in the axial direction and the first separate plate 67 located on the other side in the axial direction widens, thereby increasing the first frictional force. The engagement device 40 is disconnected.

On the other hand, when the second driven cam 50 is displaced toward the other side in the axial direction, the second separate plate 73 located on the farthest one side in the axial direction moves toward the other side in the axial direction via the second elastic member 75 and the spacer 76 . is pressed down. Based on this, the second frictional engagement device 41 is connected by the second friction plate 72 and the second separate plate 73 pressing against each other.

By switching the operation mode of the power transmission path switching device 5, the two-speed transmission 1 of this example has a high speed mode in which the reduction ratio between the input member 2 and the output member 3 is small (the reduction ratio is 1). , and a low-speed mode having a larger reduction ratio than the high-speed mode. Each case will be described below.

<High speed mode>
In order to switch the two-speed transmission 1 to the high-speed mode, the power transmission path switching device 5 is connected to the first friction engagement device 40 based on the rotation of the drive cam 48 by the electric actuator 56, and Switch to the first mode in which the second friction engagement device 41 is disconnected. When the power transmission path switching device 5 is switched to the first mode, the sun gear 11 and the carrier 13 are rotated integrally based on the connection of the first frictional engagement device 40, and the first mode is switched. Rotation of the ring gear 12 with respect to the housing 38 is permitted based on the disengagement of the two friction engagement devices 41 . In such a high-speed mode, the sun gear 11, the ring gear 12, and the carrier 13 rotate in the same direction and at the same rotational speed, so that the entire planetary gear mechanism 4 rotates together, resulting in a so-called glued state. Therefore, the power of the input member 2 is transmitted to the output member 3 through the route shown in (A) below.
(A) Input member 2 → carrier 13 → output member 3
Thus, in the high speed mode, the power of the input member 2 is transmitted to the output member 3 without being decelerated. In other words, in high speed mode the reduction ratio between the input member 2 and the output member 3 is unity.

<Low speed mode>
In order to switch the two-speed transmission 1 to the low speed mode, the power transmission path switching device 5 is disconnected, the first frictional engagement device 40 is disconnected, and The mode is switched to the first mode in which the second friction engagement device 41 is connected. When the power transmission path switching device 5 is switched to the second mode, the sun gear 11 and the carrier 13 become rotatable relative to each other based on the disengagement of the first frictional engagement device 40, and the second frictional engagement is established. Rotation of the ring gear 12 with respect to the housing 38 is prevented by connecting the coupling device 41 . In such a low speed mode, the power of the input member 2 is transmitted to the output member 3 through the route shown in (B) below.
(B) Input member 2 → Sun gear 11 → Rotational motion of pinion gear 14 → Revolving motion of pinion gear 14 based on engagement with ring gear 12 → Carrier 13 → Output member 3
Thus, in the low speed mode, the power of the input member 2 is reduced by the planetary gear mechanism 4 and transmitted to the output member 3 . The reduction ratio between the input member 2 and the output member 3 in the low speed mode is the gear ratio between the ring gear 12 and the sun gear 11 (the number of teeth of the gear portion 24 of the ring gear 12/the number of teeth of the gear portion 19 of the sun gear 11). ).

As described above, in the two-speed transmission 1 of this example, the operation mode of the power transmission path switching device 5 is switched, that is, the connection/disengagement states of the first friction engagement device 40 and the second friction engagement device 41 are switched. As a result, the speed reduction ratio between the input member 2 and the output member 3 can be switched between high and low levels. Specifically, when the power input to the input member 2 is low speed and high torque, the two-speed transmission 1 is switched to the low speed mode, and when it is high speed and low torque, it is switched to the high speed mode. For this reason, the acceleration performance and high-speed performance when an electric vehicle or a hybrid vehicle is running using only an electric motor as a drive source are defined by the left side of the point P in the solid line a in FIG. The characteristic is such that the part on the right side of the point P is continuous, and can be made close to the gasoline engine vehicle indicated by the dashed line c in FIG. 14 .

In particular, in the power transmission path switching device 5 of this example, the first friction engagement device 40 and the first friction engagement device 40 and the The connection/disconnection state of the second friction engagement device 41 is switched. That is, the power transmission path switching device 5 of this example does not require a hydraulic system for controlling friction engagement devices such as clutches and brakes. Therefore, in an electric vehicle or a hybrid vehicle, the system can be simplified, the cost can be reduced, and the power consumption performance can be improved.

Further, when the drive cam 48 is rotationally driven to switch the mode between the low speed mode and the high speed mode, the first driven cam 49 and the second driven cam 50 are displaced (advance/retreat) in opposite directions with respect to the axial direction. )do. Therefore, at the time of mode switching, the larger the fastening force of one of the first frictional engagement device 40 and the second frictional engagement device 41, the smaller the fastening force of the other frictional engagement device. . Therefore, it is possible to suppress the shift shock due to the mode switching, thereby preventing the vehicle occupants from feeling uncomfortable.

In this example, the first elastic member 69 is arranged between the first separate plate 67 and the first driven cam 49, which are located on the farthest one side in the axial direction, and the second separate plate, which is located on the farthest one side in the axial direction. A second elastic member 75 is arranged between 73 and the second driven cam 50 . Therefore, the assembly error of the power transmission path switching device 5 and the deviation due to wear of the first friction plate 66, the first separate plate 67, the second friction plate 72 and the second separate plate 73 can be 2 can be absorbed by the elastic member 75 . Therefore, by controlling the force that presses the first driven cam 49 (the force that presses the first driven cam 49 against the first separate plate 67, which is located on one side in the axial direction, toward the other side in the axial direction), the 1. The fastening force of the friction engagement device 40 can be controlled, and the force pressing the second driven cam 50 (the axis of the second driven cam 50 with respect to the second separate plate 73 existing on one side in the axial direction) The fastening force of the second friction engagement device 41 can be controlled by controlling the pressing force to the other direction. As a result, in the high speed mode, a sufficient fastening force of the first frictional engagement device 40 can be secured, and in the low speed mode, a sufficient fastening force of the second frictional engagement device 41 can be secured. can be done.

In this example, when the power transmission path switching device 5 is switched to the first mode and the first frictional engagement device 40 is connected, the first rolling element 64 is positioned on the tip surface of the convex portion of the first drive cam surface 52. It rides on the provided flat surface portion 54a. On the other hand, when the power transmission path switching device 5 is switched to the second mode and the second frictional engagement device 41 is connected, the second rolling element 65 is provided on the tip surface of the convex portion of the second drive cam surface 53 . It rides on the flat surface portion 54b. Therefore, according to the power transmission path switching device 5 of the present embodiment, even if the power supply to the transmission motor 58 is stopped after the mode switching is completed, the connected state of the first frictional engagement device 40 or the second frictional engagement is maintained. The connected state of the device 41 can be maintained, and from this point of view as well, the power consumption performance can be improved.

Instead of or in addition to providing the flat surface portions 54a and 54b on the distal end surfaces of the convex portions of the first drive cam surface 52 and the second drive cam surface 53, the driving By providing a self-locking function to the worm reduction gear consisting of the wheel gear portion 55 of the cam 48 and the worm gear portion 59 of the worm 57, the connection of the first friction engagement device 40 can be maintained even after the power supply to the shift motor 58 is stopped. The state or the connected state of the second friction engagement device 41 may be maintained.

In the two-speed transmission 1 of this example, the planetary gear mechanism 4 is arranged around the output member 3 and the power transmission path switching device 5 is arranged around the input member 2. When implementing the two-speed transmission of the first aspect of the invention, not limited to this, various configurations can be employed. For example, the planetary gear mechanism can be arranged around the input member and the power transmission path switching device can be arranged around the output member. Alternatively, the planetary gear mechanism and/or the power transmission path switching device can be arranged without radially overlapping the input member or the output member. In any case, the shape of each part is appropriately changed according to each configuration.

In addition, the cam device 39 of the power transmission path switching device 5 of this example has the first rolling element 64 and the second rolling element 64 between the driving cam 48 and the first driven cam 49 and the second driven cam 50, respectively. A moving body 65 is sandwiched. However, when implementing the power transmission path switching device of the present invention, if the first driven cam and the second driven cam can be displaced in opposite directions with respect to the axial direction with the rotation of the drive cam, this is acceptable. Without limitation, various configurations can be employed. For example, a first driving cam surface and a second driving cam surface provided on the driving cam, and a first driven cam surface provided on the first driven cam and a second driven cam surface provided on the second driven cam. The cam surface can also be brought into direct sliding contact.

[ First example of reference example ]
8 to 10B show a first reference example of the present invention. This reference example is an example in which a power transmission path switching device of another invention, which is outside the technical scope of the present invention, is applied to a two-speed transmission of the first aspect of another invention. That is, in the two-speed transmission 1a of this reference example , the structure of the cam device 39a of the power transmission path switching device 5a is different from the structure of the cam device 39 of the first example of the embodiment.

The cam device 39a of this reference example has a drive cam 48a, a first driven cam 49a and a second driven cam 50a.

The drive cam 48a includes a plurality of (for example, three or four) engaging protrusions 80 protruding in the radial direction. In this reference example , the drive cam 48a includes an annular side plate portion 81, an inner diameter side cylindrical portion 82 bent from the radially inner end portion of the side plate portion 81 toward the other side in the axial direction, and the side plate portion 81. and an outer diameter side cylindrical portion 83 protruding from the radially outer portion of the radially outer portion toward the other side in the axial direction over the entire circumference. The drive cam 48a further includes circular holes 84 radially penetrating the outer diameter side cylindrical portion 83 at a plurality of locations in the circumferential direction of the outer diameter side cylindrical portion 83. Each of the circular holes 84 is provided with an engaging pin. 85 is press-fitted. In this reference example , the engagement convex portion 80 is formed by a portion of the engagement pin 85 that protrudes radially inward from the inner peripheral surface of the outer diameter side cylindrical portion 83 . Further, the drive cam 48a further has a wheel gear portion 55a, which is a helical gear having a helical tooth trace, on the outer peripheral surface of the side plate portion 81. As shown in FIG.

The drive cam 48a is mounted on the housing 38 by arranging the angular ball bearing 51 between the inner peripheral surface of the inner diameter side tubular portion 82 and the outer peripheral surface of the end portion of the inner diameter side tubular portion 42 of the housing 38 on one side in the axial direction. It is supported so as to be rotatable with respect to it and to be axially displaceable.

The first driven cam 49a is formed to extend in the circumferential direction and has a plurality of first driven cam grooves 86 with which the engaging projections 80 engage. In this reference example , the first driven cam 49a includes an annular side plate portion 87, an outer diameter side cylindrical portion 88 bent from the radially outer end portion of the side plate portion 87 toward one side in the axial direction, and An inner diameter side cylindrical portion 89 protrudes from the radially intermediate portion of the side plate portion 87 toward the other side in the axial direction over the entire circumference.

Each of the first driven cam grooves 86 is formed on the outer peripheral surface of the outer diameter side tubular portion 88 . The first driven cam groove 86 has a linear portion 90a arranged on one side in the circumferential direction (upper side in FIGS. 10A and 10B) and one side in the axial direction when viewed from the radially outer side, A linear portion 90b arranged on the other side in the direction (lower side in FIGS. 10A and 10B) and on the other side in the axial direction, an end portion of the linear portion 90a on the other side in the circumferential direction, and the linear portion 90b and an inclined portion 91 connecting to one end in the circumferential direction of 90b. That is, the inclined portion 91 is inclined in a direction from one side to the other side in the axial direction as it goes from one side to the other side in the circumferential direction when viewed from the radially outer side.

Each of the first driven cam grooves 86 opens only on the outer peripheral surface of the outer diameter side tubular portion 88 and does not open on the inner peripheral surface of the outer diameter side tubular portion 88 . That is, in this reference example , the first driven cam groove 86 is configured by a concave groove. However, the first driven cam groove 86 can also be formed so as to penetrate the outer diameter side cylinder portion 88 in the radial direction.

The first driven cam 49 a has a first driven side female spline portion 61 a on the inner peripheral surface of the side plate portion 87 , and the first driven side female spline portion 61 a is attached to the fixed side male spline portion of the housing 38 . By spline engagement with the spline portion 45, it is supported with respect to the housing 38 so as to be displaceable only in the axial direction.

The second driven cam 50a is formed to extend in the circumferential direction and has a plurality of second driven cam grooves 92 with which the engaging projections 80 engage. In this reference example , the second driven cam 50a includes a small-diameter cylindrical portion 93 on one side in the axial direction, a large-diameter cylindrical portion 94 on the other side in the axial direction, an end portion of the small-diameter cylindrical portion 93 on the other side in the axial direction, and a cylindrical portion 94 on the other side in the axial direction. A ring portion 95 that connects the end portion of the large-diameter cylindrical portion 94 on one side in the axial direction is provided.

Each of the second driven cam grooves 92 is formed in the small-diameter cylindrical portion 93 so as to penetrate the small-diameter cylindrical portion 93 in the radial direction. The second driven cam groove 92 has an opening shape symmetrical with the first driven cam groove 86 in the axial direction. That is, the second driven cam groove 92 has a linear portion 96a arranged on one side in the circumferential direction and on the other side in the axial direction, and a straight portion 96a arranged on the other side in the circumferential direction and on one side in the axial direction. and an inclined portion 97 connecting the other end of the linear portion 96a in the circumferential direction and the one end of the linear portion 96b in the circumferential direction. That is, the inclined portion 97 is inclined in a direction from the other side in the axial direction to the other side as it goes from one side in the circumferential direction to the other side when viewed from the outside in the radial direction.

The second driven cam 50a has a second driven side male spline portion 63a on the outer peripheral surface of one end of the large-diameter cylindrical portion 94 in the axial direction. The second driven cam 50a is supported with respect to the housing 38 so as to be displaceable only in the axial direction by spline-engaging the second driven side male spline portion 63a with the fixed side female spline portion 46 of the housing 38. ing.

In the cam device 39a of the present reference example , the intermediate portion of the engagement projection 80 of the drive cam 48a engages (passes through) the second driven cam groove 92 of the second driven cam 50a, and the engagement projection A tip portion (a radially inner end portion) of the portion 80 is engaged with a first driven cam groove 86 of the first driven cam 49a. Therefore, when the electric actuator 56 rotates the drive cam 48a and the engagement protrusion 80 moves in the circumferential direction, the engagement protrusion 80 moves along the first driven cam groove 86 and the second driven cam groove 86. The first driven cam 49 a and the second driven cam 50 a are axially displaced (advance and retreat) so as to move inside the cam groove 92 . Here, since the first driven cam groove 86 and the second driven cam groove 92 have opening shapes that are symmetrical with respect to the axial direction, the first driven cam groove 86 and the second driven cam groove 92 rotate as the driving cam 48a rotates. The driven cam 50a displaces (advances and retreats) in opposite directions with respect to the axial direction.

In the power transmission path switching device 5a of this reference example , as in the power transmission path switching device 5 of the first example of the embodiment, the driving cam 48a is rotationally driven by the electric actuator 56, and the first driven cam 49a and the first driven cam 49a are rotated. Based on axially displacing the second driven cam 50a, the connection/disengagement state of the first friction engagement device 40 and the second friction engagement device 41 is switched. That is, the power transmission path switching device 5a has a first mode in which the first frictional engagement device 40 is connected and the second frictional engagement device 41 is disconnected, and a first mode in which the first frictional engagement device 40 is disconnected, Also, the second mode in which the second friction engagement device 41 is connected is switched.

<First mode>
In order to switch the power transmission path switching device 5a to the first mode, the driving cam 48a is rotationally driven by the electric actuator 56 to displace (move) the engaging convex portion 80 to one side in the circumferential direction. moves in the direction in which the axial distance from the drive cam 48a widens (the other side in the axial direction), and the second driven cam 50a moves in the direction in which the axial distance from the drive cam 48a narrows (on the other side in the axial direction). ) move to one side in the axial direction. As a result, as shown in FIG. 10(A), the engaging convex portion 80 is located between the linear portion 90a arranged on one side in the axial direction of the first driven cam groove 86 and the second driven cam groove 92. Of these, it engages with the linear portion 96a arranged on the other side in the axial direction. In other words, when the engaging protrusion 80 is displaced to one side in the circumferential direction, the engagement between the engaging protrusion 80 and the first driven cam groove 86 causes the first driven cam 49a to move in the other axial direction. The first driven cam 49a moves (is guided) toward the side, and the first driven cam 49a moves toward one side in the axial direction ( guided).

When the first driven cam 49a is displaced toward the other side in the axial direction, the first friction plate 66 and the first separate plate 67 are pressed against each other, and the first friction engagement device 40 is connected. At the same time, when the second driven cam 50a is displaced toward one side in the axial direction, the force with which the second friction plate 72 and the second separate plate 73 press against each other is released, and the second friction engagement device 41 is disconnected. be done.

<Second mode>
In order to switch the power transmission path switching device 5a to the second mode, the driving cam 48a is rotationally driven by the electric actuator 56 to displace (move) the engaging convex portion 80 to the other side in the circumferential direction. 49a moves in a direction (on one side in the axial direction) in which the axial distance from the drive cam 48a decreases, and the second driven cam 50a moves in a direction (on one side in the axial direction) in which the distance from the drive cam 48a in the axial direction increases. ) move to one side in the axial direction. As a result, as shown in FIG. 10(B), the engaging convex portion 80 is aligned with the linear portion 90b arranged on the other side in the axial direction of the first driven cam groove 86 and the second driven cam groove 92. As shown in FIG. Among them, the linear portion 96b arranged on one side in the axial direction is engaged. In other words, when the engaging protrusion 80 is displaced to the other side in the circumferential direction, the engagement between the engaging protrusion 80 and the first driven cam groove 86 causes the first driven cam 49a to move axially. The second driven cam 50a moves (is guided) to one side, and the second driven cam 50a moves axially to the other side as the engagement protrusion 80 and the second driven cam groove 92 are engaged with each other. (guided).

When the first driven cam 49a is displaced toward one side in the axial direction, the force with which the first friction plate 66 and the first separate plate 67 press against each other is released, and the first friction engagement device 40 is disconnected. At the same time, when the second driven cam 50a is displaced toward the other side in the axial direction, the second friction plate 72 and the second separate plate 73 are pressed against each other, and the second friction engagement device 41 is connected.

The two-speed transmission 1a of this example switches between the high speed mode in which the reduction ratio between the input member 2 and the output member 3 is small (the reduction ratio is 1) by switching the operation mode of the power transmission path switching device 5a. , and a low-speed mode having a larger reduction ratio than the high-speed mode. Specifically, by switching the power transmission path switching device 5a to the first mode in which the first frictional engagement device 40 is connected and the second frictional engagement device 41 is disconnected, the two-speed transmission 1a can be switched to high speed mode. On the other hand, by switching the power transmission path switching device 5a to the second mode in which the first frictional engagement device 40 is disconnected and the second frictional engagement device 41 is connected, the two-speed transmission 1a You can switch to low speed mode.

In the power transmission path switching device 5a of the present reference example , the first frictional engagement device 40 and the second 2 Switch the connection/disconnection state of the frictional engagement device 41 . Therefore, like the power transmission path switching device 5 of the first embodiment, the power transmission path switching device 5a of this reference example also includes a hydraulic system for controlling frictional engagement devices such as clutches and brakes. unnecessary.

Further, in this reference example , when the power transmission path switching device 5a is switched to the first mode, the engaging convex portion 80 is formed by the linear portion 90a of the first driven cam groove 86 and the second driven cam groove 92. engages with the straight portion 96a of the On the other hand, when the power transmission path switching device 5a is switched to the second mode, the engaging convex portion 80 is aligned with the straight portion 90b of the first driven cam groove 86 and the straight portion 96b of the second driven cam groove 92. to engage. Therefore, according to the power transmission path switching device 5a of the present reference example , similarly to the power transmission path switching device 5 of the first example of the embodiment, after the mode switching is completed, the power supply to the speed change motor 58 is stopped. However, the connected state of the first frictional engagement device 40 or the connected state of the second frictional engagement device 41 can be maintained.

In this reference example , the first driven cam groove 86 is composed of a pair of linear portions 90a and an inclined portion 91, and the second driven cam groove 92 is composed of a pair of linear portions 96b and an inclined portion. 97. However, when implementing the power transmission path switching device of the second aspect of the present invention, it is possible to displace the first driven cam and the second driven cam in opposite directions with respect to the axial direction as the drive cam rotates. If possible, any shape can be adopted for the first driven cam groove and the second driven cam groove. Other configurations and effects are the same as those of the first embodiment.

[ Second example of embodiment]
11 to 13B show a second example of the embodiment of the invention. This example is an example in which the power transmission path switching device of the present invention is applied to a two-speed transmission of the second aspect of another invention. The two-speed transmission 1b of this embodiment includes an input member 2, an output member 3a supported coaxially with and relatively rotatable with the input member 2, and a power transmission direction between the input member 2 and the output member 3a. and a power transmission path switching device 5b for switching the power transmission path between the input member 2 and the output member 3a.

The output member 3a includes an output tubular portion 9 having a female spline portion 8 on its inner peripheral surface, and an output flange portion 10a bent radially outward from one axial end of the output tubular portion 9. , an outer diameter side tubular portion 98 that is bent toward one side in the axial direction from the radially outer end portion of the output flange portion 10a, and the entire circumference from the intermediate portion in the radial direction of the output flange portion 10a toward one side in the axial direction. and a protruding inner diameter side tubular portion 99 . The output member 3 a has an output side first female spline portion 100 on the inner peripheral surface of the inner diameter side tubular portion 99 and an output side second female spline portion 101 on the inner peripheral surface of the outer diameter side tubular portion 98 . have Further, the output member 3a has through holes 102a and 102b axially penetrating through the output flange portion 10a at a plurality of circumferential locations on each of the radially inner portion and the radially outer portion of the output flange portion 10a.

The planetary gear mechanism 4a includes a sun gear 11a, a ring gear 12a, a carrier 13a, and a plurality of pinion gears 14.

The sun gear 11a is connected to the input member 2 so as to rotate together therewith. In this example, the sun gear 11a includes a tubular portion 103 and a flange portion 17a bent radially outward from one end portion of the tubular portion 103 in the axial direction. The sun gear 11a further includes a sun-side male spline portion 18a on the outer peripheral surface of the cylindrical portion 103, and further includes a gear portion 19 on the outer peripheral surface of the flange portion 17a. The cylindrical portion 103 of the sun gear 11a is externally fitted to the input cylindrical portion 6 of the input member 2 by a structure capable of transmitting torque, such as spline engagement.

The ring gear 12a is supported around the sun gear 11a coaxially with the sun gear 11a and rotatable relative to the sun gear 11a. In this example, the ring gear 12a includes a small-diameter tubular portion 20a, a large-diameter tubular portion 21a arranged coaxially with the small-diameter tubular portion 20a around the small-diameter tubular portion 20a, and a ring gear on one side of the small-diameter tubular portion 20a in the axial direction. A ring portion 22a is provided that connects an end portion and an end portion on one side in the axial direction of the large-diameter cylindrical portion 21a. The ring gear 12a further includes a gear portion 24 on the inner peripheral surface of the large-diameter cylindrical portion 21a.

In this example, the ring gear 12a is non-rotatably fitted in a portion that does not rotate during use, such as a housing (not shown). That is, the ring gear 12a does not rotate (rotation is blocked) even during use.

In this example, radial needle bearings 104 are arranged between the inner peripheral surface of the small-diameter tubular portion 20a and the outer peripheral surface of the input tubular portion 6 of the input member 2, and are arranged on both sides of the small-diameter tubular portion 20a in the axial direction. Thrust needle bearings 105a and 105b are arranged between the end face and the other axial side surface of the input flange portion 7 of the input member 2 and one axial side surface of the flange portion 17a of the sun gear 11a. Thus, the input member 2 is supported on the inner diameter side of the ring gear 12a so as to be freely rotatable with respect to the ring gear 12a.

The carrier 13a is coaxially and rotatably supported with the sun gear 11a and the ring gear 12a. In this example, the carrier 13a has a pair of rims 25c and 25d, each of which is annular and spaced apart in the axial direction, and one of the pair of rims 25c and 25d that is aligned with each other. A column portion 26 spanned between a plurality of locations in the circumferential direction, and a rim portion 25c on the other side in the axial direction of the pair of rim portions 25c and 25d. and a tubular portion 27a protruding toward the side over the entire circumference.

The carrier 13a is provided with circular holes 28c penetrating in the axial direction at a plurality of locations in the circumferential direction of a portion of the rim portion 25c on the other side in the axial direction, which is located radially outside the tubular portion 27a. A carrier-side male spline portion 71 is provided on the outer peripheral surface of the shaped portion 27a. Further, the carrier 13a axially penetrates a portion of the rim portion 25d on one side in the axial direction of the pair of rim portions 25c and 25d that is aligned with the circular hole 28c of the rim portion 25c on the other side in the axial direction. 28 d of circular holes are provided.

Each of the pinion gears 14 has its axially opposite ends of the support shaft 30 fitted and fixed in the circular holes 28c and 28d of the carrier 13a, respectively, and a body portion 31 rotatably supported by the support shaft 30. A gear portion 33 provided on the outer peripheral surface is meshed with the gear portion 19 of the sun gear 11a and the gear portion 24 of the ring gear 12a.

The power transmission path switching device 5b includes a housing 38a that does not rotate during use, a cam device 39b, a first frictional engagement device 40a, and a second frictional engagement device 41a.

The housing 38a includes an inner diameter side tubular portion 42a, an outer diameter side tubular portion 43a, an end portion on the other axial side of the inner diameter side tubular portion 42a, and an end portion on the other axial side of the outer diameter side tubular portion 43a. and a ring-shaped side plate portion 44a connecting the . The housing 38a includes a fixed male spline portion 45a on the outer peripheral surface of the inner diameter side tubular portion 42a, and a fixed female spline portion 46a on the inner peripheral surface of the outer diameter side tubular portion 43a. In addition, the housing 38a further includes a through hole 47a on the other side in the axial direction of the outer diameter side tubular portion 43a.

The cam device 39a has a drive cam 48b, a first driven cam 49b and a second driven cam 50b.

The drive cam 48b has a circular ring shape, and is mounted on the outer peripheral surface of the inner diameter side cylindrical portion 42a of the housing 38a on the other side in the axial direction via an angular ball bearing 51a capable of supporting a radial load and a thrust load. , are rotatably supported and axially displaceable. In addition, the drive cam 48a has a first drive cam surface 52a formed by alternately arranging concave portions and convex portions in the circumferential direction on the radially inner portion of one axial side surface. has a second drive cam surface 53a in which concave portions and convex portions are alternately arranged in the circumferential direction.

The drive cam 48a is rotationally driven by an electric actuator 56a. That is, a worm gear portion 59a of a worm 57a is meshed with a portion of the wheel gear portion 55a provided on the outer peripheral surface of the drive cam 48a that is exposed from the through hole 47a of the housing 38a. The worm 57a is connected to the output shaft of the speed change motor 58a.

The first driven cam 49a is arranged to face the radially inner portion of the driving cam 48a in the axial direction, and has a concave portion in the portion of the other axial side surface facing the first driving cam surface 52a. It has a first driven cam surface 60a in which convex portions are alternately arranged in the circumferential direction.

The first driven cam 49a has a first driven side female spline portion 61a on its inner peripheral surface, and the first driven side female spline portion 61a is connected to the fixed side male spline portion 45 of the housing 38a. The spline engagement allows only axial displacement with respect to the housing 38a.

The second driven cam 50a is arranged to face the radially outer portion of the driving cam 48a in the axial direction, and has a concave portion in a portion of the other axial side surface facing the second driving cam surface 53a. It has a second driven cam surface 62a in which convex portions are alternately arranged in the circumferential direction.

The second driven cam 50a has a second driven side male spline portion 63a on its outer peripheral surface, and the second driven side male spline portion 63a is splined to the fixed side female spline portion 46a of the housing 38a. By engaging them, they are supported so that they can only be displaced in the axial direction with respect to the housing 38a.

The cam device 39a includes a plurality of first rolling elements 64a that are rotatably arranged between the first driving cam surface 52a and the first driven cam surface 60a, and a plurality of rolling elements 64a that are arranged between the second driving cam surface 53a and the first driven cam surface 60a. It further includes a plurality of second rolling elements 65a that are rotatably arranged between the two driven cam surfaces 62a.

The first frictional engagement device 40a has a plurality of first friction plates 66a and first separate plates 67a each having a substantially circular ring shape and alternately arranged in the axial direction. In this example, the first frictional engagement device 40a is disposed between the output member 3a and the sun gear 11a, which are rotating bodies, respectively, and the output member 3a and the sun gear 11a rotate integrally. , and functions as a clutch that switches between the state of relative rotation with each other.

Each of the first friction plates 66a has a female spline portion on its inner peripheral surface, and the female spline portion is spline-engaged with the sun-side male spline portion 18a of the sun gear 11a, so that the sun gear 11a is axially engaged with the sun gear 11a. It is supported to allow only directional displacement.

Among the first friction plates 66a, between the first friction plate 66a, which exists on the other side in the axial direction, and the first driven cam 49a, a first elastic member 69a and a thrust member are provided in order from the other side in the axial direction. A rolling bearing 70a is arranged. In addition, in this example, the first elastic member 69a is configured by a disc spring. Thrust rolling bearing 70a includes a pair of bearing rings 106a, 106b. Of the pair of bearing rings 106a and 106b, the bearing ring 106a on one side in the axial direction has a pressing pin portion 107a projecting from one side surface in the axial direction toward the one side in the axial direction. is inserted through the through hole 102a of the output member 3a, and the tip portion is opposed to the other axial side surface of the first friction plate 66a, which is located on the farthest other axial side.

Each of the first separate plates 67a has a male spline portion on its outer peripheral surface, and by spline-engaging the male spline portion with the output-side first female spline portion 100 of the output member 3a, the output member 3a is supported to allow only axial displacement with respect to

Of the first separate plates 67a, the first separate plate 67a that exists on one side in the axial direction is axially displaced by a retaining ring 68a that is engaged with the end of the inner diameter side cylindrical portion 99 of the output member 3a on one side in the axial direction. Displacement to one side is blocked.

The second friction engagement device 41a has a plurality of second friction plates 72a and a plurality of second separate plates 73a, each of which is substantially circular and alternately arranged in the axial direction. In this example, the second frictional engagement device 41a is disposed between the output member 3a and the carrier 13a, which are rotating bodies, respectively, and the output member 3a and the carrier 13a rotate integrally. , and functions as a clutch that switches between the state of relative rotation with each other.

Each of the second friction plates 72a has a female spline portion on its inner peripheral surface, and by spline-engaging the female spline portion with the carrier-side male spline portion 71 of the carrier 13a, the carrier 13a is axially rotated. It is supported to allow only directional displacement.

Among the second friction plates 72a, between the second friction plate 72a, which is located on the other side in the axial direction, and the second driven cam 50a, a second elastic member 75a and a thrust member are provided in order from the other side in the axial direction. A rolling bearing 70b is arranged. In addition, in this example, the second elastic member 75a is configured by a disc spring. Thrust rolling bearing 70b includes a pair of bearing rings 106c, 106d. Of the pair of bearing rings 106c and 106d, the bearing ring 106c on one side in the axial direction has a pressing pin portion 107b projecting from one side surface in the axial direction toward the one side in the axial direction. is inserted through the through hole 102b of the output member 3a, and the tip portion is opposed to the other axial side surface of the second friction plate 72a, which is located on the farthest other axial side.

Each of the second separate plates 73a has a male spline portion on its outer peripheral surface, and by spline-engaging the male spline portion with the output-side second female spline portion 101 of the output member 3a, the output member 3a is supported to allow only axial displacement with respect to

Of the second separate plates 73a, the second separate plate 73a, which is located on the farthest one side in the axial direction, is axially secured by a retaining ring 74a locked to one axial end portion of the outer diameter side cylindrical portion 98 of the output member 3a. Displacement in one direction is blocked.

The power transmission path switching device 5b of this example rotates the drive cam 48b by the electric actuator 56a, and displaces the first driven cam 49b and the second driven cam 50b in the axial direction. A first mode in which the frictional engagement device 40a is connected and the second frictional engagement device 41a is disconnected, and a mode in which the first frictional engagement device 40a is disconnected and the second frictional engagement device 41a is connected. and the second mode.

<First mode>
In order to switch the power transmission path switching device 5b to the first mode, the drive cam 48b is rotationally driven by the electric actuator 56a, and the first driven cam 49b is moved in the direction in which the axial distance from the drive cam 48b increases. (one side in the axial direction), and the second driven cam 50b is displaced in the direction (other side in the axial direction) in which the axial distance from the drive cam 48b is reduced.

When the first driven cam 49b is displaced toward one side in the axial direction, the pressing pin portion 107a presses the first friction plate 66a located on the farthest other side in the axial direction toward one side in the axial direction. Based on this, the first frictional engagement device 40a is connected by the first friction plate 66a and the first separate plate 67a pressing against each other.

When the second driven cam 50b is displaced toward the other side in the axial direction, the force of pressing the second friction plate 72a and the second separate plate 73a against each other is released. As a result, the distance between the second friction plate 72a located on the other side in the axial direction and the second separate plate 73a located on the one side in the axial direction widens, thereby disconnecting the second friction engagement device 41b.

<Second mode>
In order to switch the power transmission path switching device 5b to the second mode, the drive cam 48b is rotationally driven by the electric actuator 56a, and the first driven cam 49b is moved in the direction in which the axial distance from the drive cam 48b is reduced. (the other side in the axial direction), and the second driven cam 50b is displaced in the direction (one side in the axial direction) in which the axial distance from the drive cam 48b increases.

When the first driven cam 49b is displaced toward the other side in the axial direction, the force of pressing the first friction plate 66a and the first separate plate 67a against each other is released. As a result, the distance between the first friction plate 66a located on the other side in the axial direction and the first separate plate 67a located on the one side in the axial direction widens, thereby disconnecting the first friction engagement device 40a.

When the second driven cam 50 is displaced toward one side in the axial direction, the pressing pin portion 107b presses the second friction plate 72a located on the farthest other side in the axial direction toward one side in the axial direction. Based on this, the second friction engagement device 41a is connected by pressing the second friction plate 72a and the second separate plate 73a against each other.

The two-speed transmission 1b of this example switches between the high-speed mode in which the reduction ratio between the input member 2 and the output member 3a is small (the reduction ratio is 1) by switching the operation mode of the power transmission path switching device 5b. , and a low-speed mode having a larger reduction ratio than the high-speed mode.

Specifically, by switching the power transmission path switching device 5b to the first mode in which the first frictional engagement device 40a is connected and the second frictional engagement device 41a is disconnected, the two-speed transmission 1b can be switched to high speed mode. In this high-speed mode, the output member 3a and the sun gear 11a rotate integrally based on the connection of the first frictional engagement device 40a, and the second frictional engagement device 41a is disconnected. Based on this, the output member 3a and the carrier 13a are relatively rotatable. In such a high speed mode, the power of the input member 2 is transmitted to the output member 3a through the route shown in (C) below.
(C) Input member 2 → sun gear 11a → output member 3a
Thus, in the high speed mode, the power of the input member 2 is transmitted to the output member 3a without being decelerated.

On the other hand, by switching the power transmission path switching device 5b to the second mode in which the first frictional engagement device 40a is disconnected and the second frictional engagement device 41a is connected, the two-speed transmission 1a You can switch to low speed mode. In this low-speed mode, the output member 3a and the sun gear 11a become rotatable relative to each other and the second frictional engagement device 41a is connected based on the disconnection of the first frictional engagement device 40a. , the output member 3a and the carrier 13a rotate integrally. In such a low speed mode, the power of the input member 2 is transmitted to the output member 3a through the path shown in (D) below.
(D) Input member 2→sun gear 11a→rotational motion of pinion gear 14→revolutional motion of pinion gear 14 based on engagement with ring gear 12a→carrier 13a→output member 3a
Thus, in the low speed mode, the power of the input member 2 is reduced by the planetary gear mechanism 4a and transmitted to the output member 3a.

In the power transmission path switching device 5b of this example, the first frictional engagement device 40a and the second frictional engagement device 40a are driven by energizing the speed change motor 58a of the electric actuator 56a to rotate the drive cam 48a via the worm 57a. Switches the connecting/disconnecting state of the friction engagement device 41a. Therefore, like the power transmission path switching device 5 of the first embodiment, the power transmission path switching device 5b of this example also requires a hydraulic system for controlling friction engagement devices such as clutches and brakes. do not have.

In the two-speed transmission 1b of this example, the planetary gear mechanism 4a is arranged around the input member 2, and the power transmission path switching device 5b is arranged around the output member 3a. When implementing the two-speed transmission of the second aspect, various configurations can be adopted without being limited to this. For example, the planetary gear mechanism can be arranged around the output member and the power transmission path switching device can be arranged around the input member. In this case, the shape of each part is appropriately changed according to the configuration. Other configurations and effects are the same as those of the first embodiment.

The above-described first and second examples of the embodiment and the first example of the reference example can be appropriately combined and carried out as long as there is no contradiction. Specifically, for example, the cam device 39b in the power transmission path switching device 5b of the second example of the embodiment can be replaced with the cam device 39a of the first example of the reference example .

The two-speed transmission of another invention can be used by being incorporated in a rotation transmission mechanism of various rotating mechanical devices, not limited to the electric drive system of an electric vehicle or a hybrid vehicle. Further, the power transmission path switching device of the present invention can be used by being incorporated in a rotation transmission mechanism of various rotating mechanical devices, not limited to a two-speed transmission.

1, 1a, 1b two-speed transmission 2 input member 3, 3a output member 4, 4a planetary gear mechanism 5, 5a, 5b power transmission path switching device 6 input tubular portion 7 input flange portion 8 female spline portion 9 output tubular portion Part 10, 10a Output flange portion 11, 11a Sun gear 12, 12a Ring gear 13, 13a Carrier 14 Pinion gear 15 Small diameter tubular portion 16 Large diameter tubular portion 17, 17a Flange portion 18, 18a Sun side male spline portion 19 Gear portion 20 Small diameter tubular portion 21 large-diameter cylindrical portion 22 circular ring portion 23 ring-side male spline portion 24 gear portion 25a, 25b, 25c, 25d rim portion 26 column portion 27 cylindrical portion 28a, 28b, 28c, 28d circular hole 29 carrier-side female spline portion 30 Support shaft 31 Body portion 32 Radial needle bearing 33 Gear portion 34a, 34b Retaining ring 35 Spacer 36a, 36b Thrust bearing 37 Pressing plate 38 Housing 39, 39a, 39b Cam device 40, 40a First friction engagement device 41, 41a Second Friction engagement device 42 Inner diameter cylinder 43 Outer cylinder 44 Side plate 45 Fixed male spline 46 Fixed female spline 47 Through hole 48, 48a, 48b Drive cam 49, 49a, 49b First driven cam 50, 50a, 50b second driven cam 51, 51a angular ball bearing 52, 52a first driving cam surface 53, 53a second driving cam surface 54a, 54b flat surface portion 55, 55a wheel gear portion 56, 56a electric actuator 57, 57a Worm 58, 58a Transmission motor 59 Worm gear portion 60, 60a First driven cam surface 61, 61a First driven side female spline portion 62, 62a Second driven cam surface 63, 63a Second driven side male spline Part 64, 64a First rolling element 65, 65a Second rolling element 66, 66a First friction plate 67, 67a First separate plate 68, 68a Retaining ring 69, 69a First elastic member 70, 70a Thrust rolling bearing 71 Carrier side Male spline portion 72, 72a Second friction plate 73, 73a Second separate plate 74, 74a Retaining ring 75, 75a Second elastic member 76 Spacer 78 Radial needle bearing 79 Thrust needle bearing 80 Engagement convex portion 81 Side plate portion 82 Inner diameter side cylinder portion 83 Outer diameter side cylinder portion 84 Circular hole 85 Engagement pin 86 First driven cam groove 87 Side plate portion 88 Outer diameter side cylinder portion 89 Inner diameter side cylinder portion 90a, 90b Straight portion 91 Inclined portion 92 Second driven cam groove 93 Small diameter cylindrical portion 94 Large diameter cylindrical portion 95 Circular ring portions 96a, 96b Straight portion 97 Inclined portion 98 Outer diameter side cylindrical portion 99 Inner diameter side cylindrical portion 100 Output side first female Spline portion 101 Output-side second female spline portions 102a, 102b Through hole 103 Cylindrical portion 104 Radial needle bearings 105a, 105b Thrust needle bearings 106a, 106b, 106c, 106d Bearing rings 107a, 107b Pressing pin portion 108 First return spring 109 Second return spring

Claims (13)

A drive cam that is rotatably supported so as not to be displaceable in the axial direction, and a drive cam that is supported so as to be rotatable and axially displaceable relative to the drive cam, and is in phases different from each other as the drive cam rotates. a cam device having a first driven cam and a second driven cam that are axially displaceable;
a first frictional engagement device having at least one first friction plate and at least one first separate plate supported so as to be axially displaceable relative to each other;
a second frictional engagement device having at least one second friction plate and at least one second separate plate supported so as to be axially displaceable relative to each other;
with
As the drive cam rotates,
The first frictional engagement is achieved by pressing the first friction plate and the first separate plate against each other based on displacing the first driven cam in a direction to widen the axial distance from the driving cam. When the device is connected and the second driven cam is displaced in the direction in which the axial distance from the driving cam is reduced, the force for pressing the second friction plate and the second separate plate against each other is reduced. a first mode in which release disconnects the second frictional engagement device;
By displacing the first driven cam in a direction in which the distance between the first driven cam and the drive cam in the axial direction is reduced, the force that presses the first friction plate and the first separate plate against each other is released, whereby the first (1) Disconnecting the frictional engagement device and displacing the second driven cam in a direction to widen the axial distance from the driving cam causes the second friction plate and the second separate plate to move toward each other. a second mode in which the second friction engagement device is connected by pressing together;
switches to
The drive cam has at least one engaging projection projecting in the radial direction,
The first driven cam is formed to extend in a circumferential direction and has at least one first driven cam groove with which the engaging projection engages, the first driven cam groove has an inclined portion inclined with respect to the circumferential direction at least in part,
The second driven cam is formed to extend in the circumferential direction and has at least one second driven cam groove with which the engaging projection engages, the second driven cam groove is a power transmission path switching device having an opening shape axially symmetrical with the first driven cam; The first driven cam is disposed between the first driven cam and the first frictional engagement device, and elastically biases the first driven cam and the first frictional engagement device away from each other. 1 elastic member;
A second driven cam is disposed between the second driven cam and the second frictional engagement device, and elastically biases the second driven cam and the second frictional engagement device away from each other. 2 elastic members;
The power transmission path switching device of claim 1, further comprising: a plurality of each of the first friction plates and the first separate plates, the first friction plates and the first separate plates being alternately arranged;
3. The motive power according to claim 1, further comprising a plurality of said second friction plates and said second separate plates, wherein said second friction plates and said second separate plates are alternately arranged. Transfer path switching device. The first friction engagement device further includes a first return spring that elastically biases the first friction plate and the first separate plate in a direction to separate them from each other,
4. The second friction engagement device according to any one of claims 1 to 3, further comprising a second return spring that elastically biases the second friction plate and the second separate plate in a direction to separate them from each other. 10. A power transmission path switching device according to claim 1. an input member;
an output member arranged coaxially with the input member;
a planetary gear mechanism disposed between the input member and the output member with respect to the power transmission direction;
The planetary gear mechanism includes a sun gear, a ring gear arranged coaxially with the sun gear around the sun gear, a carrier arranged coaxially with the sun gear, the sun gear and the ring gear meshing with each other, and the carrier and a plurality of pinion gears supported so as to freely rotate around their own central axis,
further comprising a power transmission path switching device for switching a power transmission path between the input member and the output member;
The power transmission path switching device,
A drive cam that is rotatably supported so as not to be displaceable in the axial direction, and a drive cam that is supported so as to be rotatable and axially displaceable relative to the drive cam, and is in phases different from each other as the drive cam rotates. a cam device having a first driven cam and a second driven cam that are axially displaceable;
a first frictional engagement device having at least one first friction plate and at least one first separate plate supported so as to be axially displaceable relative to each other;
a second frictional engagement device having at least one second friction plate and at least one second separate plate supported so as to be axially displaceable relative to each other;
with
As the drive cam rotates,
The first frictional engagement is achieved by pressing the first friction plate and the first separate plate against each other based on displacing the first driven cam in a direction to widen the axial distance from the driving cam. When the device is connected and the second driven cam is displaced in the direction in which the axial distance from the driving cam is reduced, the force for pressing the second friction plate and the second separate plate against each other is reduced. a first mode in which release disconnects the second frictional engagement device;
By displacing the first driven cam in a direction in which the distance between the first driven cam and the drive cam in the axial direction is reduced, the force that presses the first friction plate and the first separate plate against each other is released, whereby the first (1) Disconnecting the frictional engagement device and displacing the second driven cam in a direction to widen the axial distance from the driving cam causes the second friction plate and the second separate plate to move toward each other. a second mode in which the second friction engagement device is connected by pressing together;
a power transmission path switching device, wherein the power transmission path switching device further includes an electric actuator that rotationally drives the drive cam. The drive cam has a wheel gear portion on its outer peripheral surface,
6. The two-speed transmission according to claim 5, wherein the electric actuator includes a worm that meshes with the wheel gear portion, and a transmission motor that rotationally drives the worm. the input member is connected to the sun gear so as to rotate integrally with the sun gear;
the output member is connected to the carrier so as to rotate integrally therewith;
one of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the sun gear or the input member but not rotatable;
the other of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the carrier or the output member, but unrotatable;
One of the second friction plate and the second separate plate is supported so as to be axially displaceable relative to a portion that does not rotate even when in use, but not to rotate, and
7. The apparatus according to claim 5, wherein the other of said second friction plate and said second separate plate is supported so as to be axially displaceable relative to said ring gear but not rotatable. 2 speed transmission. the input member is connected to the sun gear so as to rotate integrally with the sun gear;
The ring gear is supported and fixed to a portion that does not rotate during use,
one of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the sun gear or the input member but not rotatable;
the other of the first friction plate and the first separate plate is supported so as to be axially displaceable relative to the output member and unrotatable;
one of the second friction plate and the second separate plate is supported axially displaceable relative to the carrier but not rotatable; and
7. The apparatus according to claim 5, wherein the other of said second friction plate and said second separate plate is supported so as to be axially displaceable relative to said output member but not rotatable. 2-speed transmission. The first driven cam is disposed between the first driven cam and the first frictional engagement device, and elastically biases the first driven cam and the first frictional engagement device away from each other. 1 elastic member;
A second driven cam is disposed between the second driven cam and the second frictional engagement device, and elastically biases the second driven cam and the second frictional engagement device away from each other. 2 elastic members;
A two-speed transmission according to any one of claims 5 to 8, further comprising: The drive cam has a first drive cam surface and a second drive cam surface formed by arranging concave portions and convex portions on the axial side surface with the same cycle and different phases in the circumferential direction, and
The first driven cam has a first driven cam surface on an axial side surface facing the first driving cam surface,
The second driven cam has a second driven cam surface on an axial side surface facing the second driving cam surface, and
The cam device includes a plurality of first rolling elements arranged between the first driving cam surface and the first driven cam surface, and the second driving cam surface and the second driven cam surface. 10. The two-speed transmission according to any one of claims 5 to 9, further comprising a plurality of second rolling elements arranged between and. The drive cam has at least one engaging projection projecting in the radial direction,
The first driven cam is formed to extend in a circumferential direction and has at least one first driven cam groove with which the engaging projection engages, the first driven cam groove has an inclined portion inclined with respect to the circumferential direction at least in part,
The second driven cam is formed to extend in the circumferential direction and has at least one second driven cam groove with which the engaging projection engages, the second driven cam groove 10. The two-speed transmission according to any one of claims 5 to 9, wherein has an opening shape axially symmetrical with the first driven cam. a plurality of each of the first friction plates and the first separate plates, the first friction plates and the first separate plates being alternately arranged;
12. Any one of claims 5 to 11, wherein a plurality of said second friction plates and said second separate plates are provided, and said second friction plates and said second separate plates are arranged alternately with each other. A two-speed transmission according to any one of the preceding paragraphs. The first friction engagement device further includes a first return spring that elastically biases the first friction plate and the first separate plate in a direction to separate them from each other,
The second friction engagement device according to any one of claims 5 to 12, further comprising a second return spring that elastically biases the second friction plate and the second separate plate in a direction to separate them from each other. A two-speed transmission according to any one of the preceding paragraphs.

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