JP2002266969A - Troidal type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a structure capable of restraining fluctuation of a gear ratio caused by fluctuation of inputted torque and imparting little uncomfortable feeling to a driver. SOLUTION: A truncated conic precession cam 60 is eccentrically fixed on an end part of a rod 22 of which base end part is fixed on a trunnion 7. An end part of a spool 21a of a control valve 18 is elastically allowed to abut on an outer peripheral surface of the precession cam 60. A tilting angle of a bus of the outer peripheral surface is smaller than 45 degrees, and a gain is smaller than 1. Thus, displacement of the spool 21a along the axial direction is restrained in spite of displacement of the trunnion 7 along the axial direction. By this construction, the influence of the displacement of the trunnion 7 along the axial direction to the fluctuation of the gear ratio is restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A toroidal-type continuously variable transmission according to the present invention is used as a transmission unit constituting an automatic transmission for an automobile. In particular, an object of the present invention is to reduce a sense of discomfort given to a driver by suppressing variation (fluctuation) of a gear ratio caused by elastic deformation of a trunnion even under a situation where transmitted torque fluctuates rapidly. is there.

[0002]

2. Description of the Related Art As an automatic transmission for an automobile, FIGS.
A toroidal type continuously variable transmission as schematically shown in FIG. This toroidal-type continuously variable transmission supports an input disk 2 concentrically with an input shaft 1 and is disposed concentrically with the input shaft 1 as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 62-71465. An output disk 4 is fixed to an end of the output shaft 3. Inside the casing 5 (see FIGS. 7 and 8 described later) containing the toroidal-type continuously variable transmission, it swings around the pivots 6, 6 which are twisted with respect to the input shaft 1 and the output shaft 3. Trunnions 7 and 7 are provided.

Each of the trunnions 7, 7 is provided with the above-mentioned pivots 6, 6 on the outer surfaces of both ends, one pair for each of the trunnions 7, 7 and concentric with each other. The central axis of each of the pivots 6, 6 does not intersect with the central axis of each of the discs 2, 4, but in a direction perpendicular or nearly perpendicular to the direction of the central axis of each of the discs 2, 4. It exists at a certain twist position. The trunnions 7, 7 support the base half of the displacement shafts 8, 8 at the center thereof, and swing the trunnions 7, 7 about the pivots 6, 6 to thereby allow the displacement shafts 8, 7 to swing. The inclination angles of 8, 8 can be freely adjusted. Power rollers 9, 9 are rotatably supported around the first half of the displacement shafts 8, 8 supported by the trunnions 7, 7, respectively. Then, these power rollers 9, 9 are attached to the inner surfaces 2a, 4a of the input side and output side disks 2, 4, respectively.
Sandwiched between each other.

The inner surfaces 2a and 4a of the input and output disks 2 and 4 facing each other are obtained by rotating a circular arc centered on the pivot 6 or a curve close to such circular arc. It has an arc-shaped concave surface. Then, the peripheral surfaces 9a, 9a of the power rollers 9, 9 formed on the spherical convex surfaces are brought into contact with the inner side surfaces 2a, 4a. Further, a pressing device 10 such as a loading cam device is provided between the input shaft 1 and the input side disk 2, and the input side disk 2 is
, While being elastically pressed toward the output-side disk 4, can be rotationally driven.

When the toroidal type continuously variable transmission configured as described above is used, the pressing device 1 is driven by the rotation of the input shaft 1.
0 rotates the input side disk 2 while pressing the input side disk 2 against the plurality of power rollers 9, 9. Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 via the plurality of power rollers 9, 9, and the output shaft 3 fixed to the output side disk 4 rotates.

When the rotational speed between the input shaft 1 and the output shaft 3 is changed, and when deceleration is first performed between the input shaft 1 and the output shaft 3, each of the trunnions 7, 7 to oscillate, and the peripheral surface 9a of each power roller 9, 9;
9a is the inner surface 2a of the input side disk 2 as shown in FIG.
Are displaced in such a manner that the respective displacement shafts 8 and 8 are in contact with the portion near the center and the portion near the outer periphery of the inner surface 4a of the output side disk 4, respectively.

On the other hand, when increasing the speed, the trunnions 7, 7 are swung so that the peripheral surfaces 9a, 9a of the power rollers 9, 9, as shown in FIG. A portion of the inner surface 2a near the outer periphery and the inner surface 4 of the output disk 4
Each of the displacement shafts 8 is inclined so as to abut on the portion near the center of a. If the inclination angle of each of the displacement shafts 8, 8 is set between those in FIGS. 4 and 5, an intermediate speed ratio can be obtained between the input shaft 1 and the output shaft 3.

FIGS. 6 and 7 show Japanese Utility Model Application No. 63-6929.
3 shows a more specific toroidal-type continuously variable transmission described in Microfilm No. 3 (Japanese Utility Model Laid-Open No. 1-173552). Input disk 2 and output disk 4
Are rotatably supported around the input shaft 11 having a tubular shape. A pressing device 10 is provided between the end of the input shaft 11 and the input disk 2. On the other hand, an output gear 12 is connected to the output side disk 4 so that the output side disk 4 and the output gear 12 rotate synchronously.

Axles 6, 6 provided concentrically at both ends of a pair of trunnions 7, 7 are a pair of support plates (yoke) 1
In FIGS. 3 and 13, swinging and axial directions (front and back directions in FIG. 6, FIG.
(Up and down direction). A base half of the displacement shafts 8, 8 is supported at an intermediate portion between the trunnions 7, 7. Each of these displacement shafts 8 and 8 makes the base half and the first half eccentric to each other. The base half of the trunnions 7 is rotatably supported in the middle of the trunnions 7, and the power rollers 9 are rotatably supported in the first half thereof. A synchronization cable 27 is crossed between the ends of the trunnions 7, 7 so that the inclination angles of the trunnions 7, 7 are mechanically synchronized with each other.

The pair of displacement shafts 8, 8 are provided at positions opposite to the input shaft 11 by 180 degrees. or,
The direction in which the base half and the front half of each of the displacement shafts 8, 8 are eccentric is the same direction (vertical direction in FIG. 7) with respect to the rotation direction of the input side and output side disks 2, 4. .
Further, the eccentric direction is a direction substantially orthogonal to the direction in which the input shaft 11 is provided. Accordingly, the power rollers 9 are supported so as to be slightly displaceable in the direction in which the input shaft 11 is disposed.

A thrust ball bearing is provided between the outer surface of each of the power rollers 9 and 9 and the inner surface of the intermediate portion of each of the trunnions 7 and 7 in order from the outer surface of each of the power rollers 9 and 9. 14, 14 and thrust needle bearings 15, 1
5 are provided. Of these, thrust ball bearings 14, 1
4 allows the rotation of the power rollers 9 while supporting the load in the thrust direction applied to the power rollers 9. Further, each of the thrust needle bearings 15,
Reference numeral 15 denotes the first half of each of the displacement shafts 8 and 8 and the outer ring 16 while supporting the thrust load applied from the respective power rollers 9 and 9 to the outer rings 16 and 16 constituting the respective thrust ball bearings 14 and 14. , 16 are allowed to swing about the base half of each of the displacement shafts 8, 8. Further, the trunnions 7, 7 can be displaced in the axial direction of the pivots 6, 6 by hydraulic actuators (hydraulic cylinders) 17, 17.

In the case of the toroidal type continuously variable transmission configured as described above, the rotation of the input shaft 11 is transmitted to the input side disk 2 via the pressing device 10. The rotation of the input disk 2 is transmitted to the output disk 4 via the pair of power rollers 9, and the rotation of the output disk 4 is extracted from the output gear 12.

When changing the rotational speed ratio between the input shaft 11 and the output gear 12, the above-mentioned actuators 17, 1
7, the pair of trunnions 7, 7 are respectively arranged in the opposite directions, for example, the power roller 9 on the right side of FIG. 7 is on the lower side of the figure, the power roller 9 on the left side of FIG. Displace each. As a result, the direction of the tangential force acting on the contact portions between the peripheral surfaces 9a, 9a of the power rollers 9, 9 and the inner surfaces 2a, 4a of the input disk 2 and the output disk 4 changes. (Side slip occurs at the contact portion). Then, with the change in the direction of the force, the trunnions 7, 7 swing in opposite directions about the pivots 6, 6 pivotally supported by the support plates 13, 13, respectively. As a result, as shown in FIGS. 4 and 5 described above, the peripheral surfaces 9a and 9a of the power rollers 9 and the inner surfaces 2 and
a, 4a, and the rotation speed ratio between the input shaft 11 and the output gear 12 changes.

The supply / discharge state of the pressure oil to / from each of the actuators 17, 17 is controlled by one control valve regardless of the number of the actuators 17, 17, and the movement of any one of the trunnions 7 is controlled by this control valve. Feedback is provided to the valve. The structure of this part is described in, for example, JP-A-6-257661, and is conventionally known. However, a second example of the conventional concrete structure, which will be described later, is shown in FIG. explain. The control valve 18 is moved in the axial direction (the left-right direction in FIG. 10) by a stepping motor 19.
And a spool 21 which is a movable member for switching a flow path according to claim 1, which is fitted on the inner diameter side of the sleeve 20 so as to be freely displaceable in the axial direction. The rod 22 attached to any one of the trunnions 7
A precess cam 23 is fixed to the end of the rod 2 through the precess cam 23 and the link arm 24.
2 constitutes a feedback mechanism for transmitting the movement of the spool 2 to the spool 21. It should be noted that the spool 21 may be driven by the stepping motor 19 to displace the sleeve 20 in the axial direction by the movement of the rod 22, contrary to the case shown in the figure. In this case, the sleeve 20
Becomes the movable member for switching the flow path.

When the gearshift state is switched, the sleeve 20 is displaced by a predetermined amount by the stepping motor 19 to open the flow path of the control valve 18. As a result, pressure oil is sent to the actuators 17 and 17 in a predetermined direction, and the actuators 17 and 17 are pressed.
Displaces the trunnions 7, 7 in a predetermined direction. That is, the trunnions 7, 7 swing about the respective pivots 6, 6 while being displaced in the axial direction of the respective pivots 6, 6 with the feeding of the pressure oil. Then, the movement (axial direction and swing displacement) of any one of the trunnions 7 described above.
Is a precess cam 23 fixed to the end of the rod 22
And the link arm 24 to the spool 21 to displace the spool 21 in the axial direction. As a result, with the trunnion 7 displaced by a predetermined amount, the flow path of the control valve 18 is closed, and the actuator 1
The supply and discharge of the pressure oil to and from the pumps 7 and 17 are stopped. Therefore, the amount of displacement of each of the trunnions 7, 7 in the axial direction and the swinging direction only depends on the amount of displacement of the sleeve 20 by the stepping motor 19.

In the conventional case, the length of a pair of arms forming the link arm 24 is made equal to each other, and the displacement amount X of the spool 21 in the axial direction (the left-right direction in FIG. 10) is calculated. The gain of the feedback mechanism, which is represented by the ratio X / Y to the movement amount Y of the precess cam 23 in the axial direction of the pivot 6 (the vertical direction in FIG. 10), is approximately 1 (X
/ Y ≒ 1). Then, the precess cam 23
Even if the inclination angle of the cam surface is not particularly increased, the axial movement amount of the spool 21 can be sufficiently secured when the trunnion 7 is inclined.

When power is transmitted by the toroidal-type continuously variable transmission, the power rollers 9 are displaced in the axial direction of the input shaft 11 (FIGS. 6 and 7) based on the elastic deformation of each component. Then, the respective displacement shafts 8 supporting the respective power rollers 9 slightly rotate about the respective base halves. As a result of this rotation, the outer surfaces of the outer rings 16, 16 of the thrust ball bearings 14, 14 and the inner surfaces of the trunnions 7, 7 are relatively displaced. Since the thrust needle bearings 15, 15 exist between the outer surface and the inner surface, the force required for the relative displacement is small.

Further, in order to increase the torque that can be transmitted, as shown in FIGS. 8 and 9, two input disks 2A and 2B and two output disks 4 and 4 are provided around the input shaft 11a. A so-called double-cavity structure in which two input disks 2A and 2B and two output disks 4 and 4 are arranged in parallel with respect to the power transmission direction is also conventionally known. The structure shown in FIGS. 8 and 9 supports an output gear 12a around an intermediate portion of the input shaft 11a so as to freely rotate with respect to the input shaft 11a, and a cylindrical portion provided at the center of the output gear 12a. The output disks 4 are spline-engaged at both ends.
Each of the input side disks 2A and 2B is connected to the input shaft 1
The input shaft 11a is rotatably supported at both ends of the shaft 1a. The input shaft 11a is driven by the drive shaft 25
It is rotationally driven via a loading cam type pressing device 10.

In the case of the toroidal type continuously variable transmission of the double cavity type as described above, the transmission of power from the input shaft 11a to the output gear 12a is performed between one input side disk 2A and the output side disk 4. And the other input side disk 2B
And the output side disk 4 is divided into two systems, so that large power can be transmitted. In the case of such a double-cavity toroidal-type continuously variable transmission, the trunnions 7, 7 are displaced in the axial direction of the pivots 6, 6 by the hydraulic actuators 17, 17 during gear shifting. As described above, only one control valve 18 is provided in the entire toroidal-type continuously variable transmission for controlling the supply and discharge of the pressure oil to and from the actuators 17 for shifting. And
This one control valve 18 allows a plurality of actuators 1
The supply and discharge of pressure oil to and from 7, 17 are controlled.

In the case where the toroidal type continuously variable transmission configured and operated as described above is incorporated in an actual continuously variable transmission for an automobile, it is known to construct a continuously variable transmission in combination with a planetary gear mechanism. -169169, 1-312
266, 10-196759, 11-
As described in JP 63146 Gazette and the like, it has been conventionally proposed. That is, the torque applied to the toroidal-type continuously variable transmission during high-speed traveling is transmitted by transmitting the driving force of the engine only at the time of low-speed traveling by the toroidal-type continuously variable transmission, and transmitting the driving force by the planetary gear mechanism at high-speed traveling. Is to be reduced. By configuring in this way,
The durability of each component of the toroidal-type continuously variable transmission can be improved.

FIG. 11 is a diagram showing the structure of Japanese Unexamined Patent Publication No.
1 shows a continuously variable transmission described in JP-A-196759. The continuously variable transmission includes an engine 2 as a drive source.
A start clutch 30 is provided between the output side end (the right end in FIG. 11) of the crankshaft 28 and the input side end (the left end in FIG. 11) of the input shaft 29. Also, the input shaft 2
An output shaft 31 for taking out power based on the rotation of No. 9 is arranged in parallel with the input shaft 29. A toroidal type continuously variable transmission 32 is provided around the input shaft 29, and a planetary gear mechanism 33 is provided around the output shaft 31.

A cam plate 34 which constitutes the pressing device 10 of the toroidal type continuously variable transmission 32 is fixed to an intermediate portion of the input shaft 29 near an output end (rightward in FIG. 11). Also, the input side disk 2 and the output side disk 4
The input shaft 29 is rotatably supported independently of the input shaft 29 by a bearing (not shown) such as a needle bearing around the input shaft 29. The cam plate 34 and the input-side disk 2 constitute the pressing device 10. Therefore, the input side disk 2 is connected to the input shaft 29.
With the rotation of, the disk rotates while being pressed toward the output side disk 4. Further, a plurality of power rollers 9, 9 are sandwiched between the inner surface 2a of the input disk 2 and the inner surface 4a of the output disk 4, and the toroidal type as shown in FIGS. The continuously variable transmission 32 is configured. still,
The toroidal type continuously variable transmission 32 is similar to that shown in FIGS.
In addition to the single cavity type shown in FIG. 7, a double cavity type as shown in FIGS. A continuously variable transmission incorporating a toroidal type continuously variable transmission of a double cavity type is disclosed in Japanese Patent Application Laid-Open No. H11-6314.
No. 6 and the like.

The sun gear 35 constituting the planetary gear mechanism 33 is fixed to the input end of the output shaft 31 (the right end in FIG. 11). Therefore, the output shaft 31 rotates with the rotation of the sun gear 35. This sun gear 3
5, a ring gear 36 is supported concentrically with the sun gear 35 and rotatably. And, between the inner peripheral surface of the ring gear 36 and the outer peripheral surface of the sun gear 35, a plurality (usually 3 to 4) of planetary gear sets 37, 37
Is provided.

In the illustrated example, each of these planetary gear sets 37, 3
7 comprises a pair of planetary gears 38a, 38b. These planetary gears 38a, 3
8b meshes with each other, meshes the planetary gear 38a arranged on the outer diameter side with the ring gear 36, and meshes the planetary gear 38b arranged on the inner diameter side with the sun gear 35. Thus, each planetary gear set 37, 37
The pair of planetary gears 38a and 38b
This is to make the rotation directions of the ring gear 36 and the sun gear 35 coincide. Therefore, if there is no need to make the rotation directions of the ring gear 36 and the sun gear 35 coincide with each other in relation to other components, a single planetary gear meshes with both the ring gear 36 and the sun gear 35. You may let it.
The above-mentioned planetary gear sets 37, 37 are rotatably supported on one side surface (the right side surface in FIG. 11) of the carrier 39.
The carrier 39 is provided at an intermediate portion of the output shaft 31.
It is rotatably supported.

Further, the carrier 39 and the output side disk 4 are connected by a first power transmission mechanism 40 so as to be capable of transmitting a rotational force. The first power transmission mechanism 40 includes first and second gears 41 and 42 meshed with each other.
It consists of. Accordingly, the carrier 39 rotates in a direction opposite to the output side disk 4 at a speed corresponding to the number of teeth of the first and second gears 41 and 42 with the rotation of the output side disk 4.

On the other hand, the input shaft 29 and the ring gear 3
Reference numeral 6 indicates that the second power transmission mechanism 43 can be freely connected to a state in which torque can be transmitted. The second power transmission mechanism 43 includes first and second sprockets 44, 45
And a chain 46 bridged between the two sprockets 44, 45. That is, the first sprocket 44 is connected to the output end of the input shaft 29 (FIG. 11).
The right end of the transmission shaft 47 is fixed to the portion protruding from the cam plate 34, and the second sprocket 45 is fixed to the input end of the transmission shaft 47 (the right end in FIG. 11). Therefore, with the rotation of the input shaft 29, the transmission shaft 47 moves in the same direction as the input shaft 29 in the first and second sprockets 4.
It rotates at a speed corresponding to the number of teeth 4 and 45.

Further, the continuously variable transmission includes a clutch mechanism constituting a mode switching means according to a third aspect of the present invention. This clutch mechanism connects only one of the carrier 39 and the transmission shaft 47 that is a component of the second power transmission mechanism 43 to the ring gear 36. In the case of the structure shown in FIG. 11, this clutch mechanism includes a low-speed clutch 48 and a high-speed clutch 49. The low speed clutch 48 is provided between the outer peripheral edge of the carrier 39 and one axial end of the ring gear 36 (the left end in FIG. 11). At the time of connection, such a low speed clutch 48 is connected to the sun gear 35 constituting the planetary gear mechanism 33.
, And the sun gear 35 and the ring gear 36 are integrally connected. The high-speed clutch 49 is provided between the transmission shaft 47 and a center shaft 51 fixed to the ring gear 36 via a support plate 50. When one of the low-speed clutch 48 and the high-speed clutch 49 is connected, the connection of the other clutch is disconnected.

In the example shown in FIG.
And a fixed clutch such as a housing (not shown) of the continuously variable transmission. The reverse clutch 52 is provided to rotate the output shaft 31 in the reverse direction so as to reverse the vehicle. The reverse clutch 52 is in a state in which one of the low speed clutch 48 and the high speed clutch 49 is connected.
Connection is lost. When the reverse clutch 52 is connected, the low-speed clutch 48 and the high-speed clutch 49 are both disconnected.

In the illustrated example, the output shaft 31 and the differential gear 53 are connected to the third to fifth gears 54 to 54.
The third power transmission mechanism 57 is connected by a third power transmission mechanism 57. Therefore, when the output shaft 31 rotates, the pair of left and right drive shafts 58, 58 rotates via the third power transmission mechanism 57 and the differential gear 53, thereby rotating the drive wheels of the automobile.

In the continuously variable transmission constructed as described above, first, at the time of low-speed running, the low-speed clutch 48 is connected, and the high-speed clutch 49 and the reverse clutch 52 are disconnected. When the starting clutch 30 is connected and the input shaft 29 is rotated in this state, only the toroidal type continuously variable transmission 32 transmits power from the input shaft 29 to the output shaft 31. The operation of changing the speed ratio between the input and output disks 2 and 4 during such low-speed running is the same as that of the toroidal type continuously variable transmission shown in FIGS. It is. Of course, in this state,
The gear ratio between the input shaft 29 and the output shaft 31, that is, the gear ratio of the continuously variable transmission as a whole is proportional to the gear ratio of the toroidal-type continuously variable transmission 32. In this state, the torque input to the toroidal continuously variable transmission 32 is equal to the torque applied to the input shaft 29.

On the other hand, during high-speed running, the high-speed clutch 49 is connected and the low-speed clutch 48 and the reverse clutch 52 are disconnected. In this state, when the starting clutch 30 is connected and the input shaft 29 is rotated, the first and second sprockets constituting the second power transmission mechanism 43 are connected from the input shaft 29 to the output shaft 31. The power is transmitted by the gears 44, 45 and the chain 46 and the planetary gear mechanism 33.

That is, when the input shaft 29 rotates during the high-speed running, the rotation is transmitted to the center shaft 51 via the second power transmission mechanism 43 and the high-speed clutch 49,
The ring gear 36 to which the central shaft 51 is fixed is rotated. The rotation of the ring gear 36 is transmitted to the sun gear 35 via the plurality of planetary gear sets 37, 37, and rotates the output shaft 31 to which the sun gear 35 is fixed. When the ring gear 36 is on the input side, the planetary gear mechanism 33 assumes that each of the planetary gear sets 37, 37 is stopped (does not revolve around the sun gear 35).
The speed is increased at a speed ratio according to the ratio of the number of teeth between the ring gear 36 and the sun gear 35. However, each of the above planetary gear sets 3
The gears 7 and 37 revolve around the sun gear 35, and the gear ratio of the continuously variable transmission as a whole is determined by each of these planetary gear sets 37 and 37.
It changes according to the revolution speed of 37. Therefore, by changing the speed ratio of the toroidal type continuously variable transmission 32 and changing the revolution speed of the planetary gear sets 37, 37, the speed ratio of the entire continuously variable transmission can be adjusted.

That is, the planetary gear sets 37 revolve in the same direction as the ring gear 36 during the high-speed running. The lower the revolution speed of each of the planetary gear sets 37, 37, the higher the rotation speed of the output shaft 31 to which the sun gear 35 is fixed. For example, if the revolution speed becomes equal to the rotation speed of the ring gear 36 (both angular speeds), the rotation speed of the ring gear 36 becomes equal to the rotation speed of the output shaft 31.
On the other hand, if the revolution speed is lower than the rotation speed of the ring gear 36, the rotation speed of the output shaft 31 is higher than the rotation speed of the ring gear 36. On the contrary, if the revolution speed is higher than the rotation speed of the ring gear 36, the rotation speed of the output shaft 31 is lower than the rotation speed of the ring gear 36.

Therefore, during the high-speed running, as the speed ratio of the toroidal type continuously variable transmission 32 is changed to the speed reduction side, the speed ratio of the entire continuously variable transmission changes to the speed increasing side. In such a state at the time of high-speed running, torque is applied to the toroidal type continuously variable transmission 32 from the output side disk 4 instead of from the input side disk 2 (when the torque applied at low speed is plus torque, minus torque is applied). Torque is applied). That is, when the high-speed clutch 49 is connected, the torque transmitted from the engine 26 to the input shaft 29 is applied to the second power transmission mechanism before the pressing device 10 presses the input side disk 2. The power is transmitted to the ring gear 36 of the planetary gear mechanism 33 via 43. Therefore, almost no torque is transmitted from the input shaft 29 to the input disk 2 via the pressing device 10.

On the other hand, a part of the torque transmitted to the ring gear 36 of the planetary gear mechanism 33 via the second power transmission mechanism 43 is transmitted from the respective planetary gear sets 37, 37 to the carrier 39 and the first Through the power transmission mechanism 40 to the output side disk 4. As described above, the torque applied from the output side disk 4 to the toroidal type continuously variable transmission 32 changes the speed ratio of the toroidal type continuously variable transmission 32 to the speed reduction side in order to change the speed ratio of the entire continuously variable transmission to the speed increasing side. The smaller the value, the smaller it becomes. As a result, the torque input to the toroidal type continuously variable transmission 32 during high-speed traveling can be reduced, and the durability of the components of the toroidal type continuously variable transmission 32 can be improved.

Further, when the output shaft 31 is reversely rotated to reverse the vehicle, the low speed and high speed clutches 48 and 49 are disconnected and the reverse clutch 52 is connected. As a result, the ring gear 36 is fixed, and the respective planetary gear sets 37, 37 mesh with the ring gear 36 and the sun gear 35, and revolve around the sun gear 35. And this sun gear 3
5 and the output shaft 31 to which the sun gear 35 is fixed rotate in the opposite direction to the above-described low-speed running and the above-described high-speed running.

FIG. 12 shows the speed ratio (icvt) of the toroidal type continuously variable transmission 32 when the speed ratio (itotal) of the continuously variable transmission as shown in FIG. 11 is continuously changed. , The input torque (T _in ) input to the toroidal type continuously variable transmission 32 and the output shaft 31 of the continuously variable transmission.
The figure shows an example of a state in which the output torque (T _s ) taken out of the power supply changes. Each of these gear ratios (itotal) (icv
t) and the relationship between the torques (T _in ) and (T _s ) include the shift width of the toroidal type continuously variable transmission 32, the structure and the gear ratio of the planetary gear mechanism 33, the reduction ratio of the second power transmission mechanism 43, and the like. It changes according to. As a condition for obtaining each line shown in FIG. 12, the speed change width of the toroidal type continuously variable transmission 32 is quadrupled (0.5 to 2.0), and the planetary gear mechanism 33 is a pair of planetary gears. And a second power transmission mechanism 4
The reduction ratio of 3 was set to 2. The switching between the low speed clutch 48 and the high speed clutch 49 is performed when the speed ratio (itotal) of the continuously variable transmission is 1 as a whole.

FIG. 1 shows the result of a trial calculation under the above conditions.
2, the vertical axis represents the gear ratio of the toroidal continuously variable transmission 32.
(Icvt) and the input torque of the toroidal type continuously variable transmission 32.
Luc (T_in) Or the output torque of the continuously variable transmission (T_s )When
From the engine 26 to the input shaft 29 (FIG. 11)
Torque (T_e ) And the ratio (T_in/ T_e ) (T_s / T
_e ), And the horizontal axis represents the gear ratio (it
otal) respectively. In addition, toroidal type stepless
The value indicating the transmission ratio (icvt) of the transmission 32 is negative.
Is the output incorporated in the toroidal type continuously variable transmission 32.
The rotation direction of the side disk 4 (FIG. 11) is the rotation of the input shaft 29.
This is because it is opposite to the direction. The solid line a represents the toroider.
The dashed line b indicates the transmission ratio (icvt) of the
The output torque (T_s ) And the input from the engine 26
Torque transmitted to the shaft 29 (T_e ) And the ratio (T_s / T
_e ), And the dashed line c indicates the input torque (T_in) And the en
Gin 26 to the input shaft 29 (T
_e ) And the ratio (T_in/ T_e ) Respectively. This
As is clear from the description of FIG. 12 as in FIG.
According to the continuously variable transmission as shown in
The torque applied to the dull-type continuously variable transmission 32 can be reduced.
Under the conditions obtained in FIG. 12, the input torque (T_in),
At most, the information transmitted from the engine 26 to the input shaft 29
Torque (T_e ) Can be reduced to about 14%.

[0039]

The toroidal type continuously variable transmission as described above, which is used in a state where it is incorporated in the above-described continuously variable transmission or the like, includes a control valve 18 (FIG. 10) provided by a precess cam 23. Regardless of the opening / closing control, the gear ratio unnecessarily fluctuates with the fluctuation of the input torque due to the influence of the assembling gap of the components of the toroidal type continuously variable transmission 32 or the elastic deformation, and the engine speed rapidly increases. The experiment by the inventors of the present invention has revealed that there is a possibility that the driver may feel uncomfortable. In particular, it has been found that when the direction of the torque sent through the toroidal-type continuously variable transmission changes, the unnecessary change in the speed ratio becomes significant.

That is, according to the experiment performed by the present inventors,
When the torque sent through the toroidal type continuously variable transmission fluctuates, the speed ratio of the toroidal type continuously variable transmission becomes
It turned out that it changed even though there was no command for shifting. FIG. 13 shows the results of such an experiment.
In the experiment, the gear ratio of the toroidal type continuously variable transmission was set to 1 (constant speed).
The rotational speed of the input shaft was set to 2000 min ^-1 and the temperature of the traction oil was raised in the same manner as when the vehicle was actually running. Under such conditions, the torque applied to the input shaft was changed between -250 Nm and +350 Nm. The torque was changed gradually to minimize the effect of inertia. The state where the torque applied to the input shaft is negative is a state where torque is transmitted from the output side disk to the input side disk. As is evident from the results of experiments conducted under such conditions, the gear ratio of the toroidal-type continuously variable transmission fluctuates with a change in the torque transmitted by the toroidal-type continuously variable transmission. The cause of the fluctuation is considered as follows.

As shown in FIG. 10 described above, the precess cam 23 is attached to one of the trunnions 7 at the base end thereof (FIG. 10).
10 (see FIG. 10).
At the lower end of the frame). On the other hand, during operation of the toroidal-type continuously variable transmission, the trunnion 7 receives a large force from the power roller 9 supported on the inner side. This force is mainly of the following two types. A force applied with power transmission from a contact portion (traction portion) between the peripheral surface 9a of the power roller 9 and the inner surfaces 2a of the input disks 2, 2A, 2B and the inner surface 4a of the output disk 4. The power roller 9 is moved to the trunnion 7 based on a pressing force by a pressing device 10 (for example, see FIGS. 8 to 9).
Thrust load that presses against the inside surface of All of these forces cause the position of the precess cam 23 to shift from the normal position.

First, the reason why the position of the precess cam 23 shifts from the normal position due to the above-mentioned force will be described with reference to FIG.
4 will be described. FIG. 14 shows a pair of trunnions 7, 7 disposed between a pair of input side disks and an output side disk, and displacement shafts 8, 8 respectively attached to these trunnions 7, 7, and power. Rollers 9, 9, rods 22, 22, hydraulic actuators 17, 17
(See, for example, FIG. 10)
And the precess cam 23 are schematically shown. This FIG.
Therefore, the input side disk not described in FIG.
It rotates clockwise as indicated by arrow α. Therefore, the output side disk, also not shown in FIG. 14, rotates counterclockwise.

FIG. 14A shows a case where power is not transmitted between the input disk 2 and the output disk 4 (for example, see FIG. 6). In this case, the load applied to each of the power rollers 9, 9 from the inner side surfaces 2a, 4a (for example, see FIG. 6) of the input side disk 2 and the output side disk 4 is zero. Accordingly, the load applied to the displacement shafts 8 and 8 supporting the power rollers 9 and 9 and the trunnions 7 and 7 is also zero, and the displacement shafts 8 and 8 are inclined or the trunnions 7 and 7 are inclined.
7 does not deform elastically. For this reason, the precess cam 23 fixed to the end of the rod 22 attached to one of the trunnions 7 (the right side in FIG. 14) exists at the regular position indicated by the chain line A in FIG.

Next, FIG. 14B shows a case where relatively light power is transmitted between the input side disk 2 and the output side disk 4. In this case, the trunnions 7, 7 are provided at both ends of the trunnions 7, 7 based on the loads applied to the power rollers 9, 9 from the inner side surfaces 2a, 4a of the input disk 2 and the output disk 4. A load is applied in the axial direction (vertical direction in FIG. 14) of the pivots 6, 6 (for example, see FIG. 10). The actuator 1 incorporating the pistons 59, 59 to support this load.
The hydraulic pressure is raised at 7 and 17. At the same time, based on the load applied to the power rollers 9 from the disks 2 and 4, the displacement shafts 8 supporting the power rollers 9 are exaggerated in FIG. 14B. As shown
It inclines forward in the direction in which the load applied to the power rollers 9 from the input side disk 2 acts. Such an inclination is caused by the existence of an internal clearance of a radial needle bearing provided between both ends of each of the displacement shafts 8, 8 and the power rollers 9, 9 and the trunnions 7, 7, and the displacement shafts. 8, 8 based on its own elastic deformation. Although such inclination is slight, the internal clearance of the thrust ball bearing 14 and the thrust needle bearing 15 (for example, see FIG. 10) provided between the power rollers 9 and 9 and the trunnions 7 and 7, respectively. Performed with relatively light force, based on being.

When the displacement shafts 8 and 8 are tilted in this manner, the power rollers 9 and 9 supported by the displacement shafts 8 and 8 are driven by the input and output disks 2 and 4 respectively.
And the peripheral surface 9 of each of these power rollers 9
a, 9a and the inner surfaces 2a, 4a of these discs 2, 4
The position of the contact portion (traction portion) is shifted from the center position of the two disks 2 and 4. When the traction portion deviates from the center position of the two disks 2 and 4 in this way, the traction portion between the peripheral surfaces 9a and 9a of the power rollers 9 and the inner side surfaces 2a and 4a of the two disks 2 and 4 is increased. Side slip occurs. Then, based on such a side slip, a known feedback mechanism operates to return the traction portion to the center position between the disks 2 and 4. That is, based on the side slip, the respective trunnions 7, 7 together with the respective power rollers 9, 9 are oscillated about the pivots 6, 6, and the precess cam 23 is connected to the control valve 18 via the link arm 24. The spool 21 (see FIG. 10) is displaced. Then, pressure oil is supplied to and discharged from the actuators 17, 17 to displace the trunnions 7, 7 in the axial direction of the pivots 6, 6, and return the traction portion to the central position of the disks 2, 4. . At this time, since no command signal for shifting has been issued, the sleeve 20 (see FIG. 10) of the control valve 18 remains at the same position (does not displace in the axial direction). As a result, each of the power rollers 9 performs a shift operation even though a command signal for shifting is not output. Then, the precess cam 23, the offset from the normal position shown by a chain line b in the axial direction by [delta] _1, will be present in a chain line B position.

FIG. 14C shows a case where a large power is transmitted between the input side disk 2 and the output side disk 4. In this case, not only the above-mentioned force but also the above-mentioned force acts in a direction to shift the position of the precess cam 23 from the normal position. That is, in the state shown in FIG. 14C, the inclination of each of the displacement shafts 8 becomes larger than in the case of FIG. 14B, and at the same time, the elastic deformation of each of the trunnions 7, 7 cannot be ignored. become.
In this case, the middle part of each of these trunnions 7, 7
Based on the thrust load applied from each of the power rollers 9, as shown in an exaggerated manner in FIG. 14C, the inner surface side on which these power rollers 9, 9 are installed is elastically deformed in a direction in which it becomes concave. . Then, based on this elastic deformation, the total length of the trunnions 7, 7 in the axial direction of the pivots 6, 6 is reduced. More specifically, the longitudinal end faces of the trunnions 7, 7 are displaced in a direction approaching the longitudinal central portions of the trunnions 7, 7.

As a result of this displacement, the precess cam 23 is further deviated from the position shown by the chain line B by δ ₂ more than in the case of FIG. That is, in this state, the deviation of the precess cam 23 from the normal position indicated by the chain line A is (δ ₁ + δ ₂ ). And
The contact portion (traction portion) between the peripheral surfaces 9a, 9a of the power rollers 9, 9 and the inner surfaces 2a, 4a of the input and output disks 2, 4 is equal to the (δ ₁ + δ ₂ ). However, the discs 2 and 4 deviate from the center position. As a result, each of the power rollers 9, 9 performs the shift operation by the amount of (δ ₁ + δ ₂ ), even though no command signal for shifting is output. Note that the new displacement δ
₂ is the sum of the amount based on the elastic deformation of the trunnion 7 and the amount based on the inclination angle of the displacement shaft 8 being further increased.

As described above, in the cases shown in FIGS. 14B and 14C, the shift operation is performed even though the command signal for the shift is not output. Is proportional to the axial deviation {δ ₁ or (δ ₁ + δ ₂ )} and the cam lead of each of the precess cams 23. For example, if the cam lead is 20 mm / 360 degrees, and if the deviation is 0.3 mm, each of the power rollers 9, 9 is set to 5.0.
4 degrees (oscillating displacement about the pivots 6 and 6). Therefore, to suppress the displacement of the precess cam 23 to be small,
This is important from the viewpoint of suppressing unintended shift operations based on the above-described causes.

An unintended shift operation also occurs due to the deflection of the rod 22 due to the elastic deformation of the trunnion 7 on which the precess cam 23 is installed. In this regard,
This will be briefly described with reference to FIG. At the time of power transmission, the trunnion 7 is exaggerated at its center by a thick chain line in FIG. 15 in a direction in which the inner surface becomes concave, based on a thrust load received from the power roller 9 supported on the inner surface. Elastically deformed. Then, based on this elastic deformation, the rod 22 having its base end (upper end in FIG. 15) connected and fixed to the end of the trunnion 7 is displaced. And
The distal end (the lower end in FIG. 15) of the rod 22 to which the precess cam 23 is mounted has a larger displacement in the radial direction as the thrust load increases. Such a displacement also causes the unintended shifting operation to be performed.

As is clear from the above description, the magnitude of the deviation of the precess cam 23 from the normal position, which causes an unintended shifting operation, changes according to the magnitude of the force applied to the power roller 9. Also, the magnitude of this force is
It changes almost in proportion to the magnitude of the torque transmitted by the toroidal type continuously variable transmission. For this reason, the speed ratio of the toroidal-type continuously variable transmission changes in accordance with the change in the torque even when no signal for changing the speed ratio is output. In any case, if an unintended shift operation is performed, the engine speed changes suddenly at that moment, giving the driver a sense of discomfort. Although it is difficult to completely eliminate such unintended gear shifting operation, it is important to keep it as small as possible from the viewpoint that stable driving is performed and the driver does not feel uncomfortable.

In particular, in the case of a continuously variable transmission in which the toroidal type continuously variable transmission 32 and the planetary gear mechanism 33 are combined as shown in FIG. 11 described above, it is clear from the chain line c in FIG. As described above, at the moment when the low speed clutch 48 and the high speed clutch 49 are switched, the torque transmission direction is reversed. In the case of such a structure, an unnecessary change in the speed ratio caused by a change in the torque passing through the toroidal-type continuously variable transmission 32 becomes large, and the discomfort given to the driver tends to be remarkable. This point will be described with reference to FIG.

As shown in FIG. 16 (A), the torque passing through the toroidal type continuously variable transmission is continuously varied from a positive value to a negative value. As shown, a command signal for shifting is not issued (the sleeve 20 of the control valve 18 shown in FIG. 10 is not displaced). In this case, the gear ratio of the toroidal type continuously variable transmission is as shown in FIG.
As shown in (C) of FIG. 6, in response to the fluctuation of the torque,
It fluctuates due to the force as described above. However, even if the fluctuation of the torque is linear, the fluctuation of the gear ratio is non-linear.

In order to suppress the fluctuation of the gear ratio as shown in FIG. 16C, which occurs in this manner, as shown in FIG.
It is conceivable to issue a command signal for shifting (displace the sleeve 20 of the control valve 18 shown in FIG. 10) in response to a change in torque passing through the toroidal-type continuously variable transmission.
That is, a command signal for shifting is issued as shown in FIG. 17B in response to a torque change as shown in FIG.
As a result, fluctuations in the speed ratio of the toroidal-type continuously variable transmission can be suppressed to a small level as shown in FIG.

However, as is clear from the comparison between FIGS. 16A and 16C, the direction in which the torque fluctuates and the direction in which the speed ratio fluctuates coincide over the entire range of the fluctuation. Therefore, even if a command signal for shifting is simply issued in response to a change in torque, it may be difficult to sufficiently eliminate unnecessary shifting. That is, even when the control as shown in FIGS. 17A and 17B is performed, based on the difference between the direction in which the torque fluctuates and the direction in which the gear ratio fluctuates, as shown in FIG. However, unnecessary speed ratio fluctuations still occur.

In any case, FIG. 16C and FIG.
(C), in the case of the continuously variable transmission in which the toroidal type continuously variable transmission and the planetary gear mechanism are combined, the gear ratio becomes large before and after the torque direction (±) is reversed at the time of mode switching. fluctuate. The change in the direction of the torque also occurs due to the conversion between the acceleration state and the operation state of the engine brake, and also in this case, the change in the gear ratio occurs. However, in this case, since the driver operates the accelerator pedal greatly, even if the change in the gear ratio is large, the driver does not feel a sense of discomfort. On the other hand, since the change in the direction of the torque in the continuously variable transmission is performed irrespective of the driver's intention, the driver has a great sense of discomfort.

For this reason, in a toroidal type continuously variable transmission incorporated in the above-described continuously variable transmission, it is important to suppress a change in a speed ratio caused by a torque change. Needless to say, even in the case of a structure that is not combined with a planetary gear mechanism and is used alone with a toroidal-type continuously variable transmission, it is still preferable to realize a structure that can suppress a change in the speed ratio due to a torque change. In view of such circumstances, the present invention has been made to reduce the degree of unintended shift operation.

[0057]

The toroidal-type continuously variable transmission according to the present invention comprises an input side disk and an output side disk, and a plurality of trunnions, similarly to the above-described conventionally known toroidal type continuously variable transmission. , A displacement shaft, a power roller, a hydraulic actuator, and a control valve. The input-side disk and the output-side disk are rotatably supported concentrically with their inner surfaces, each having an arc-shaped concave surface, facing each other. Each of the trunnions swings about a pivot axis which is twisted with respect to the central axis of the input side disk and the output side disk. The displacement shaft is supported at an intermediate portion of each of the trunnions in a state of protruding from the inner surface of each of the trunnions. The power roller is disposed on the inner surface side of each of the trunnions, and is rotatably supported around each of the displacement shafts while being sandwiched between the input side disk and the output side disk. The peripheral surface is a spherical convex surface. The hydraulic power roller is provided for each trunnion, and by displacing each of the trunnions in the axial direction of each of the pivots, each of the trunnions is rocked and displaced about each of the pivots. Thus, the speed ratio between the input side disk and the output side disk is changed. Further, the control valve is for switching the supply / discharge state of the pressure oil to / from each of the actuators. Then, a precess cam is fixed to a member that is displaced together with any of the trunnions, a feedback mechanism for transmitting the displacement of the precess cam to the control valve is provided, and the movement of the trunnion is transmitted to the flow path switching movable member of the control valve, and the By displacing the flow switching member in the axial direction, the supply / discharge state of the control valve can be switched.

In particular, in the toroidal type continuously variable transmission according to the present invention, the ratio of the displacement X of the flow path switching movable member in the axial direction to the displacement Y of the precess cam in the axial direction of the pivot shaft. The gain of the feedback mechanism represented by X / Y is set to less than 1. In this case, the gain is preferably set to 0.3 to 0.8, more preferably 0.3 to 0.6.

Further, in order to obtain such a gain, there is provided a second embodiment.
As described above, a precess cam having a truncated cone shape is used. Then, such a truncated cone-shaped precess cam is fixed to an end of one of the trunnions in a state where the center axis of the precess cam and the center axis of the pivot axis are eccentric. In this case, in order to make the gain less than 1, the inclination angle θ of the generatrix of the outer peripheral surface of the precess cam, which is a conical convex surface, to the center axis of the precess cam is made less than 45 degrees. Then, the end of the portion that moves in the axial direction together with the flow path switching movable member is elastically abutted against the outer peripheral surface of the precess cam. The gain is set to a preferable value of 0.3 to 0.
In order to set to 8, the inclination angle θ is set to tan ⁻¹ 0.3 ≦ θ
≦ tan ⁻¹ 0.8, and similarly, in order to obtain a more preferable value of 0.3 to 0.6, tan ⁻¹ 0.3 ≦ θ ≦ tan
^-1 0.5.

[0060]

According to the toroidal type continuously variable transmission of the present invention configured as described above, it is possible to suppress a change in the gear ratio caused by a sudden change in the torque, and reduce a sense of discomfort given to the driver. That is, since the gain of the feedback mechanism is set to less than 1, even when the precess cam is displaced based on elastic deformation of the trunnion or the like due to torque fluctuation, the displacement amount of the flow path switching movable member accompanying this displacement is suppressed to a small value. Can be Then, the change in the gear ratio, which is proportional to the axial displacement amount of the flow path switching movable member, can be suppressed to reduce the sense of discomfort given to the driver.

[0061]

1 and 2 show an embodiment of the present invention. The toroidal-type continuously variable transmission according to the present invention is characterized in that, in order to suppress a change in the transmission ratio when the transmitted torque fluctuates, the deformation amount or the deformation direction of each component based on the fluctuation of the torque is controlled. However, there is a point that it does not lead to switching of the control valve as it is. The structure of the other parts, and the operation of transmitting power between the input unit and the output unit or changing the speed ratio between the input unit and the output unit, are conventionally known. It is the same as a toroidal type continuously variable transmission. Therefore, the illustration and description of the overlapping portions are omitted or simplified, and the feedback for transmitting the movement of any trunnion 7, which is a characteristic portion of the present invention, to the spool 21 a of the control valve 18 will be described below. The structure and operation of the mechanism will be described.

In the case of this example, any one of the trunnions 7 (left side in FIG. 1) is used to constitute the above-mentioned feedback mechanism.
Rod 2 having its base end (upper end in FIG. 1) connected and fixed to
The precess cam 60 is fixed to the front end portion (the lower end portion in FIG. 1) of the second cam 2. The precess cam 60 has a rotationally symmetrical truncated cone shape, and has a central axis O ₂₂ and the trunnion 7.
The trunnions 7 are fixed to the ends of the trunnions 7 via the rods 22 in a state where the center axes O ₆ (FIG. 2) of the pivots _{6 and 6} are eccentric. The amount of eccentricity δ between the two central axes O ₂₂ and O ₆ is determined by design considerations in order to make the relationship between the inclination angle of the trunnion 7 and the amount of axial displacement of the spool 21a described below appropriate. I do.

The end of the spool 21 a constituting the control valve 18, which is a movable member for switching the flow path, is elastically abutted against the outer peripheral surface of the precess cam 60. That is,
The output shaft 61 of the stepping motor 19 for projecting the spool 21 a toward the precess cam 60 from the sleeve 20 and displacing the sleeve 20.
10 (see FIG. 10), the distal end surface of the spool 21a is elastically pressed toward the outer peripheral surface of the precess cam 60. In addition, this spool 2
The distal end surface of 1a is a spherical convex surface so that the distal end surface and the outer peripheral surface of the precess cam 60 are smoothly in sliding contact with each other.

[0064] Further, the generatrix of the outer peripheral surface of said precess cam 60, the inclination angle theta with respect to the center axis O ₂₂ of the precess cam 60 is less than 45 degrees (theta <45 °). Accordingly, the displacement amount X of the spool 21a in the axial direction is expressed by:
The precess cam 60 in the axial direction of the pivots 6, 6
The gain of the feedback mechanism, represented by the ratio X / Y to the movement amount Y, is less than 1 (X / Y <1). Preferably, the gain is set to 0.3 to 0.8. For this purpose, the inclination angle θ is set to tan ⁻¹ 0.3 (about 16 degrees 4
0 min) ≦ θ ≦ tan ⁻¹ 0.8 (approximately 38 degrees 40 minutes). Similarly, in order to obtain a more preferable value of 0.3 to 0.5, tan ⁻¹ 0.3 ≦ θ ≦ tan ^-1 0.5 (approximately 26 degrees 35
Minutes).

According to the toroidal type continuously variable transmission of the present invention configured as described above, a change in the speed ratio caused by a sudden change in the torque can be suppressed, and the uncomfortable feeling given to the driver can be reduced.
That is, as is apparent from the above description of FIG. 14, the precess cam 60 is displaced to some extent in the axial direction of the pivots 6 with the fluctuation of the torque input to the toroidal type continuously variable transmission. Inevitable. In the case of the conventional structure shown in FIG. 10 described above, the axial displacement of the precess cam 23 due to the torque fluctuation is directly applied to the spool 21 of the control valve 18.
Therefore, the amount of switching of the control valve 18 becomes large, and the degree of shifting unintended by the driver tends to be remarkable. On the other hand, according to the structure of the present example, only a part of the axial displacement of the precess cam 60 due to the torque fluctuation is transmitted to the spool 21a of the control valve 18, so that
The switching amount of the control valve 18 is suppressed to a small amount, and the degree of unintended shifting by the driver can be suppressed to a low level.

FIG. 3 shows an analysis performed by the present inventor on the effect of the gain (X / Y) between the precess cams 23 and 60 and the spools 21 and 21a on the change in the speed ratio due to the torque change. Shows the results. FIG. 3 is an analysis based on an experiment conducted on the influence of torque fluctuation on the speed ratio, incorporating a factor of the speed ratio fluctuation as described above, and confirming the consistency with the experimental result in advance. is there. 3A shows the case where the gain is 1 as in the conventional structure, FIG. 3B shows the case where the gain is set to 0.5 according to the present invention, and FIG. And (D) shows the results when the same was set to 0.1. FIG. 3 (A) ~
As is clear from the comparison of (D), by keeping the gain low, fluctuations in the speed ratio due to torque fluctuations can be reduced even with respect to the width W between the maximum value and the minimum value of the speed ratio. The width w between the values can also be kept low. Then, it is possible to reduce a sense of discomfort given to the driver.

As is clear from the above description, as in the present invention, the precess cams 23, 60 and the spools 21, 21 are provided.
a, the fluctuation of the gear ratio due to the torque fluctuation can be suppressed. However, if this gain is too small, the axial displacement of the trunnion 7 is
As shown in FIG. 3 (D),
Shift control becomes unstable. Therefore, in consideration of ensuring the stability of the shift control, it is preferable to secure the gain at least 0.3 or more.

As is apparent from the above description, according to the present invention, as shown in FIG. 14, the precess cams 23, 60 are displaced in the axial direction of the pivots 6, 6 according to the torque fluctuation. The fluctuation of the speed ratio based on the rod 22 swaying in the radial direction as shown in FIG. 15 cannot be prevented. However, the change in the gear ratio caused by the cause as shown in FIG. 15 can be achieved by installing the spool 21a of the control valve 18 at a position that is hardly affected by the swing of the rod 22 (the front-back direction position in FIG. 15).
Can be kept low.

Further, according to the present invention, by combining the toroidal type continuously variable transmission 32 and the planetary gear mechanism 33, power is transmitted only by the toroidal type continuously variable transmission 32 during low speed traveling, and the planetary gear mechanism during high speed traveling. The present invention is not limited to a structure incorporated in a so-called power split type continuously variable transmission, in which main power is transmitted by 33 and a gear ratio is adjusted by a toroidal type continuously variable transmission 32. For example, the present invention can also be applied to an automatic transmission constituted by a toroidal-type continuously variable transmission alone. Furthermore, by combining a toroidal type continuously variable transmission with a planetary gear mechanism, the clutch can be switched from retreating to stopping and even to the forward state without any switching, and is incorporated into a continuously variable transmission called geared neutral. Also applicable to continuously variable transmissions. Even in the case of a toroidal type continuously variable transmission incorporated in such a continuously variable transmission called geared neutral, it is effective from the viewpoint of suppressing fluctuations in the gear ratio when switching between high speed and low speed modes and when operating the engine brake. In addition to the above, it is effective to apply the present invention also from the viewpoint of preventing fluctuation of the gear ratio when the forward / backward movement is switched after the stop state.

However, according to the present invention, the center of swing of each power roller is more than the line connecting the contact points (traction points) between the peripheral surface of each power roller and the input side and output side disks. This is useful when applied to a so-called half toroidal type continuously variable transmission that exists radially outward. On the other hand, as described in, for example, JP-A-62-63263, the center of swing of each power roller exists on a straight line connecting a pair of traction points.
In the case of a so-called full toroidal type continuously variable transmission, the necessity of applying the present invention is low. That is, in the case of a full toroidal type continuously variable transmission, the force applied to each of the power rollers from the traction points that are present at two points for each of the power rollers except for the force corresponding to the traction force, Offset internally. Therefore, elastic deformation or the like of each part is unlikely to lead to fluctuation of the gear ratio. In addition, in the case of a full toroidal type continuously variable transmission, the speed change method itself is different from that of a half toroidal type continuously variable transmission. Is scarce.

[0071]

Since the present invention is constructed and operates as described above, it is possible to realize a toroidal-type continuously variable transmission which does not require any troublesome control and which can reduce a sense of discomfort given to the driver.

[Brief description of the drawings]

FIG. 1 is a sectional view similar to FIG. 10, showing an example of an embodiment of the present invention;

FIG. 2 is a view of the precess cam as viewed from below in FIG. 1;

FIG. 3 is a diagram illustrating an influence of a difference in gain on a relationship between a change in input torque and a change in gear ratio.

FIG. 4 is a schematic side view showing a basic structure of the toroidal-type continuously variable transmission in a state of maximum deceleration.

FIG. 5 is a schematic side view similarly showing a state at the time of maximum speed increase.

FIG. 6 is an essential part cross-sectional view showing a first example of a specific structure of the toroidal type continuously variable transmission.

FIG. 7 is a sectional view taken along line xx of FIG. 6;

FIG. 8 is an essential part cross-sectional view showing a second example of the specific structure of the toroidal-type continuously variable transmission.

FIG. 9 is a sectional view taken along line yy of FIG. 8;

FIG. 10 is a cross-sectional view of the same zz.

FIG. 11 is a schematic sectional view showing an example of a continuously variable transmission incorporating a toroidal-type continuously variable transmission.

FIG. 12 is a diagram showing a relationship between a speed ratio of the entire continuously variable transmission, a speed ratio of only the toroidal type continuously variable transmission, and a torque ratio of each part.

FIG. 13 is a diagram showing a state in which a gear ratio changes in response to a change in input torque in a conventional structure.

FIG. 14 is a schematic diagram for explaining the reason why the gear ratio greatly fluctuates in the conventional structure.

FIG. 15 is a cross-sectional view of the trunnion and the rod, for explaining the reason why the elastic deformation of the trunnion leads to a shift (fluctuation) in the gear ratio.

FIG. 16 is a diagram showing a state in which a change in torque input to the toroidal-type continuously variable transmission is linked to a change in speed ratio.

FIG. 17 is a diagram showing a case where a command signal for shifting is issued in response to a change in torque in order to suppress a change in speed ratio.

[Explanation of symbols]

 Reference Signs List 1 input shaft 2, 2A, 2B input disk 2a inner surface 3 output shaft 4 output disk 4a inner surface 5 casing 6 pivot 7 trunnion 8 displacement shaft 9 power roller 9a peripheral surface 10 pressing device 11, 11a input shaft 12, 12a Output gear 13 Support plate 14 Thrust ball bearing 15 Thrust needle bearing 16 Outer ring 17 Actuator 18 Control valve 19 Stepping motor 20 Sleeve 21, 21a Spool 22 Rod 23 Precess cam 24 Link arm 25 Drive shaft 26 Engine 27 Synchronous cable 28 Crank shaft 29 Input shaft Reference Signs List 30 starting clutch 31 output shaft 32 toroidal-type continuously variable transmission 33 planetary gear mechanism 34 cam plate 35 sun gear 36 ring gear 37 planetary gear set 38a, 38b planetary gear 39 carrier 40 first power transmission device Structure 41 First gear 42 Second gear 43 Second power transmission mechanism 44 First sprocket 45 Second sprocket 46 Chain 47 Transmission shaft 48 Low speed clutch 49 High speed clutch 50 Support plate 51 Center shaft 52 For retreat Clutch 53 Differential gear 54 Third gear 55 Fourth gear 56 Fifth gear 57 Third power transmission mechanism 58 Drive shaft 59 Piston 60 Precess cam 61 Output shaft 62 Compression spring

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J051 AA03 BA03 BB01 BD01 BE09 CA05 CB04 DA02 DA05 FA02 3J062 AA02 AB35 AC03 BA40 CG02 CG13 CG32 CG38 CG52 CG82

Claims (3)

[Claims] An input disk and an output disk which are concentrically and rotatably supported in a state where their inner surfaces which are concave surfaces having an arc-shaped cross section are opposed to each other; A plurality of trunnions that swing about a pivot axis that is twisted with respect to the center axis of the disk and the output side disk, and a displacement supported at a middle portion of each of the trunnions in a state of protruding from the inner surface of each of the trunnions. A shaft, which is disposed on the inner surface side of each of the trunnions and is rotatably supported around each of the displacement shafts while being sandwiched between the input side disk and the output side disk. A power roller having a convex surface is provided for each of the trunnions. By displacing each of the trunnions in the axial direction of each of the pivots, each of the trunnions is displaced from each of the trunnions. A hydraulic actuator that changes the gear ratio between the input-side disk and the output-side disk by oscillating displacement about a shaft, and a control valve for switching between supply and discharge states of pressure oil to each of the actuators A precess cam is fixed to a member that is displaced together with any of the trunnions, and a feedback mechanism for transmitting the displacement of the precess cam to the control valve is provided, and the movement of the trunnion is transmitted to the flow path switching movable member of the control valve. In the toroidal-type continuously variable transmission in which the supply / discharge state of the control valve can be freely switched by displacing the lever for switching the passage in the axial direction, the movable member for switching the passage in the axial direction is controlled. The gain of the feedback mechanism, which is represented by the ratio X / Y of the displacement amount X and the movement amount Y of the precess cam in the axial direction of the pivot, is less than 1. Toroidal type continuously variable transmission according to claim. 2. A precess cam having a truncated cone shape, wherein the precess cam is fixed to an end of a trunnion with its center axis and a center axis of a pivot being eccentric, and an outer peripheral surface of the precess cam having a conical convex surface. The inclination angle of the generatrix with respect to the center axis of this precess cam is less than 45 degrees,
The toroidal-type continuously variable transmission according to claim 1, wherein an end of a portion that moves in the axial direction together with the flow path switching movable member is elastically abutted against an outer peripheral surface of the precess cam. 3. A toroidal-type continuously variable transmission is incorporated in a continuously variable transmission. The continuously variable transmission includes an input shaft connected to a drive source and rotationally driven by the drive source. An output shaft for extracting power based on the rotation of the input shaft, the toroidal-type continuously variable transmission, a planetary gear mechanism, and transmitting the power input to the input shaft via the toroidal-type continuously variable transmission. A first power transmission mechanism, and a second power transmission mechanism that transmits power input to the input shaft without passing through the toroidal-type continuously variable transmission,
The planetary gear mechanism is provided between a sun gear and a ring gear disposed around the sun gear, and includes a planetary gear rotatably supported by a carrier that is rotatably supported concentrically with the sun gear. The sun gear and the ring gear are meshed with each other, and the power transmitted through the first power transmission mechanism and the power transmitted through the second power transmission mechanism are the sun gear and the ring gear. The output shaft is coupled to the remaining one of the sun gear, the ring gear, and the carrier, and the output shaft is connected to two members of the carrier. And a mode switching means for switching a state in which the power input to the planetary gear mechanism is transmitted through the first power transmission mechanism and the second power transmission mechanism. A first mode in which power is transmitted only by at least the first power transmission mechanism, and a second mode in which power is transmitted by both the first power transmission mechanism and the second power transmission mechanism. 3. The toroidal-type continuously variable transmission according to claim 1, wherein the toroidal type continuously variable transmission switches between modes.