JPH0861454A - Continuously variable transmission - Google Patents

Abstract

PURPOSE: To achieve continuously variable gear changes, using a simple structure, to match increase or decrease in the input number of revolution by achieving gear changes through the movement of the gear changing ring of a ring-cone type continuously variable transmission along its major axis, which is caused by the radial movement of a presser resulting from the action of a centrifugal force due to the rotation of the input side. CONSTITUTION: An input shaft 4 and a transmission shaft 2 leading to a hydraulic pump 1 are supported on the same axis, and an input disc 31 and an output disc 32 are mounted on the butt ends of the respective shafts 4, 2, and a plurality of circumferentially arranged planetary cones 33 are brought into rolling contact with the outer peripheries of the discs. A gear changing ring 34 which rolls into contact with the cone generator of the planetary cones 33 is integrally held against a cam 40. A cam face 44 is pressed by a centrifugal force working on a presser 46 located on support rods 45... projected radially outward from one side of the input disc 31, and thereby the cam 40 and the gear changing ring 34 are moved against a spring 43 so that, when power is transferred from the input shaft 4 to the transmission shaft 2, the transmission gear ratio is varied by changes in the positions where the cam 40 and the gear changing ring 34 roll into contact with the planetary cones 33....

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission used in a transmission system of various automobile auxiliaries driven by an engine, for example.

[0002]

2. Description of the Related Art Recent automobiles are equipped with various auxiliary equipment such as a hydraulic pump for supplying hydraulic oil to a power steering device or an automatic transmission, a battery charging generator, an air conditioning compressor and the like. Most of these are driven by an engine as a drive source, for example, by belt transmission via a crank pulley provided at an end of a crankshaft.

However, when the rotation of the engine is directly transmitted to this type of auxiliary machine, there is a problem that a large power loss is caused at the time of high-speed operation with a high engine speed, and such a power loss is caused. When the specifications of the auxiliary machines are determined to be kept low, there is a problem that the capacity of each auxiliary machine is insufficient during low speed operation. Therefore, conventionally, a transmission is provided in the middle of the transmission system to each accessory, and the transmission ratio of this transmission is changed according to the level of the input rotation speed from the engine. When it is low, it is transmitted to the auxiliary machine as it is, and when the input speed is high, it is transmitted to the auxiliary machine after a predetermined deceleration, so that the above-mentioned problem is solved.

As the transmission, a continuously variable transmission capable of continuously changing gears is often used. This is to prevent a sudden change in the engine load due to the change in the above-mentioned gear ratio and prevent the deterioration of the running stability. Further, the change of the gear ratio in the transmission is generally realized by a configuration in which the input rotation speed from the engine is detected and the gear change actuator is operated based on the detection result.
However, in this case, the entire structure of the transmission becomes complicated,
In addition to the increase in size, it is difficult to secure the installation space in the middle of the transmission system from the engine, and there is a risk of malfunction due to the influence of external noise.

That is, a desirable structure of the transmission used in the transmission system of the automobile accessory is that the change of the gear ratio according to the level of the input rotation speed can be realized steplessly by a simple mechanical means. There is a continuously variable transmission capable of doing this, as disclosed in JP-A-63-82876 and JP-A-61-228155.
Japanese Patent Publication Nos.

The continuously variable transmission disclosed in Japanese Patent Laid-Open No. 63-82876 has been proposed as an example of application to a hydraulic pump that supplies hydraulic oil to a power steering device. The output shaft to the hydraulic pump is connected via a variable pitch pulley that changes the gear ratio by changing the effective diameter, while a steel ball is placed outside the conical half that constitutes the variable pitch pulley on the output shaft side. The steel ball is moved radially outward by the action of centrifugal force due to the rotation of the output shaft, and presses the half body inward, that is, in the direction of approaching the other half body. .

According to this structure, the effective diameter of the variable pitch pulley on the output shaft side increases as the halves come closer to each other according to the movement of the steel balls, while the movement of the steel balls depends on the rotational speed of the output shaft. Since it occurs with the increase, the gear ratio from the input shaft to the output shaft is continuously changed to the deceleration side as the rotation speed of the output shaft increases.

Further, the continuously variable transmission disclosed in Japanese Patent Laid-Open No. 61-228155 basically has an input disk on the input side from the engine and an output disk on the output side to the auxiliary machine. , While rolling on multiple planet cones in the circumferential direction interposed between them, the planet cones roll together on their respective cone generatrix parallel to the axes of the input and output discs. A gearshift ring in contact with the planetary cone is changed by moving the gearshift ring in the axial direction so that the gear ratio during transmission from the input side to the output side can be changed steplessly. A ring cone type continuously variable transmission, a centrifugal force drive gear pivotally supported on a predetermined circumference centered on an axis, and an annular cam member provided with an internal gear that meshes with the outside thereof. The roller key protruding from the speed change ring on the cam surface of this cam member. And it has a meta configuration.

In this structure, when the centrifugal drive gear rotates about the pivot shaft, the cam member meshing with the centrifugal drive gear rotates via the internal gear, the transmission ring is pressed via the roller key, and the shaft length increases. The gear shifts in the direction. The centrifugal force drive gear is provided with a weight portion that is eccentric from the pivot shaft at one location in the circumferential direction, and the weight portion is moved in the radial direction by the centrifugal force that acts according to the rotation on the circumference of the arrangement. Rotate around the pivot so that it is on the outside. Therefore, the gear ratio from the input side to the output side is continuously changed to the deceleration side as the rotation speed on the output side increases.

[0010]

[Problems to be Solved by the Invention] By the way, JP-A-63-82876
In the continuously variable transmission disclosed in the publication, the effective diameter of the variable pitch pulley on the output shaft side is increased / decreased according to the movement of the steel ball due to the action of the centrifugal force, so that gear shifting is performed. However, in order to increase the effective diameter of the variable pitch pulley on the output shaft side, a force that resists the tension of the transmission belt wound between the variable pitch pulley on the input shaft side is required. Is not enough. That is, JP-A-63-828
The continuously variable transmission disclosed in Japanese Unexamined Patent Publication No. 76 has a problem in that it is difficult to realize a gear shifting operation and lacks practicality.

On the other hand, in the continuously variable transmission disclosed in Japanese Unexamined Patent Publication No. 61-228155, a large force is not required to move the speed change ring in the axial direction of the speed change gear. The operation is performed smoothly. However, a precision component that requires high machining accuracy, such as a cam member having an internal gear and a centrifugal force drive gear that meshes with this cam member, is required, and it is difficult to process and assemble these components. There is.

Further, in any of the conventional continuously variable transmissions configured as described above, gear shifting is performed in accordance with an increase / decrease in the number of revolutions on the output side, and an increase / decrease in the number of revolutions on the output side is input. It is not possible to obtain the characteristic opposite to that of the side, that is, the characteristic that the output rotation speed decreases in accordance with the increase of the input rotation speed from the engine, but such a characteristic cannot be obtained. May be required in.

For example, in a hydraulic pump for supplying hydraulic oil for a power steering device, a road surface reaction force acting on a steering wheel is small during high speed traveling and a steering assist force is hardly required. It is sufficient to supply a smaller amount of oil than the time. However, when the conventional continuously variable transmission is used, the rotational speed of the hydraulic pump on the output side does not decrease with the increase of the engine rotational speed on the input side, but only increases while decreasing the rate of increase. First, during high speed operation, the hydraulic pump is driven at a high rotational speed to supply unnecessary hydraulic oil that is not used for steering assistance. It is known that the power consumption of the hydraulic pump is approximately proportional to the cube of the number of revolutions, and the power loss of the engine due to the generation of the unnecessary hydraulic oil described above is large, and the driving performance and fuel consumption of the vehicle are deteriorated. Invite.

That is, in the hydraulic pump for the power steering apparatus, this rotation is transmitted without deceleration in the region where the input rotation speed from the engine is low, and this rotation is sufficiently reduced in the region where the input rotation speed is high. However, such a shift cannot be realized by the conventional continuously variable transmission having the above-mentioned configuration.

The present invention has been made in view of the above circumstances, and it is possible to reliably realize stepless speed change according to an increase or decrease in the input rotation speed with a simple structure, and to change the output rotation speed. It is possible to provide a continuously variable transmission suitable for use in a transmission system of an auxiliary machine for an automobile, in which the aspect can be set appropriately, and the characteristic that the increase and decrease of the output rotation speed is opposite to the increase and decrease of the input rotation speed is obtained. To aim.

[0016]

In a continuously variable transmission according to the present invention, an input disc and an output disc are respectively attached to end portions of the input shaft and the output shaft, which are coaxially supported, opposite to each other. The outer circumference of each of them is rotatably contacted with a plurality of planetary cones in the circumferential direction interposed therebetween, and the planetary cones are collectively attached to the planetary cones on the respective cone generatrix parallel to the axes of the input shaft and the output shaft. Equipped with a speed change ring for rolling contact, so that the position of rolling contact with each planet cone can be changed by moving the speed change ring in the axial direction so that the speed ratio during transmission from the input shaft to the output shaft can be changed steplessly. In the continuously variable transmission, the pressing body that moves in the radial direction by the action of the centrifugal force that accompanies the rotation of the input shaft and the inclination angle in the cross section including the axial center of the input shaft and the output shaft in the radial direction. The cam surface, which is different from the A Te, characterized by comprising a cam member for moving the control ring in response to the pressing of the cam surface by pressing pressure body on the deceleration side.

In addition, the inclination angle of the cam surface is set so as to become smaller with respect to the axial center from the inner diameter side to the outer diameter side.

[0018]

In the present invention, the pressing body moves in the radial direction by the action of the centrifugal force corresponding to the rotation of the input shaft, and presses the cam surface of the cam body facing this moving range, and by this pressing, the transmission ring. Shifts in the axial direction and shifts to the deceleration side. At this time, the gear ratio at the time of transmission from the input shaft to the output shaft changes in accordance with the increase / decrease in the rotation speed on the input side, and is determined regardless of the rotation speed on the output side. Further, the cam surface has different inclination angles in the radial direction which is the moving direction of the pressing body, and the pressing of the cam surface by the pressing body is performed according to the inclination angle at each moving position. The change mode depends on the change mode of the inclination angle of the cam surface, and the change mode of the output rotation speed can be set appropriately.

Further, when the inclination angle of the cam surface with respect to the axis is set to be smaller from the inner diameter side to the outer diameter side, in the low speed rotation range where the pressing of the cam surface by the pressing body is performed on the inner diameter side. In the high-speed rotation range in which the pressing ratio is small with respect to the movement of the pressing body and the pressing is performed on the outer diameter side, the changing ratio of the transmission ratio with respect to the movement of the pressing body is large, and the rotation speed of the output shaft is While the shaft rotation speed is kept high while the rotation speed of the input shaft is low, it rapidly decreases as the rotation speed of the input shaft increases, and the increase and decrease of the output rotation speed is opposite to the increase and decrease of the input rotation speed.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a vertical cross-sectional view showing an application example of the continuously variable transmission according to the present invention to a hydraulic pump for supplying an operating hydraulic pressure to a power steering apparatus.

The illustrated hydraulic pump 1 has a short cylindrical rotor 10 for holding a plurality of vanes so as to be capable of advancing and retracting in the radial direction.
And a cam ring 11 having an uneven thickness annular shape. The cam ring 11 is housed inside the pump housing 14 together with the pressure plate 12 coaxially positioned on one side thereof, and the end plate 13 and the pressure plate 12 for closing the other side of the pump housing 14.
It is pinched between and. Further, the rotor 10 is loosely fitted inside the cam ring 11, and the pressure plate 12
End plate through the axial center of the cam ring 11
A transmission shaft 2 having its tip end supported by 13 is fitted so as to rotate coaxially inside the cam ring 11 in accordance with the rotation of the transmission shaft 2.

The hydraulic pump 1 as described above operates so as to generate hydraulic pressure in a plurality of pump chambers which are arranged in the circumferential direction between the outer circumference of the rotor 10 and the inner circumference of the cam ring 11. These pump chambers are attached to the suction pipe 15 attached to the upper outside of the pump housing 14, the end plate 13 and the pump housing.
It communicates with a suction oil passage 16 formed in the peripheral wall of 14, and also communicates with a discharge pipe (not shown) through a pressure chamber 17 formed on the back side of the pressure plate 12.

The suction pipe 15 is connected to an oil tank (not shown) that stores the hydraulic oil of the power steering device. When the rotor 10 rotates due to the rotation of the transmission shaft 2, the suction pipe 15 is provided in each pump chamber outside the rotor 10. The working oil is introduced through the suction pipe 15 and the suction oil passage 16. The plurality of vanes held by the rotor 10 press their respective tips against the inner peripheral surface of the cam ring 11, follow the irregularities of the inner circumference, and move forward and backward in the radial direction while rotating with the rotor 10, and each pump chamber The hydraulic oil introduced into the engine is sealed between the adjacent vanes, is rotated together with the rotor 10 to increase the pressure, and is supplied to the power steering device via the pressure chamber 17 and the discharge pipe.

The pump housing 14 includes an end plate 13
Is provided with a cylindrical connecting bracket 18 that is coaxially projected on the opposite side of the closed portion, and the stepless according to the present invention is provided inside the transmission housing 30 that is coaxially assembled to the end surface of the connecting bracket 18. The transmission 3 is configured.

The continuously variable transmission 3 has an input disc 31 and an output disc.
The outer circumference of 32 and the outer circumference of the planetary cones 33, 33 ... are rotatably contacted with the bottom surfaces of a plurality of planetary cones 33, 33 ... The ring-shaped speed-change ring 34 is collectively rolled on the conical generatrix of the planet cones 33, 33 ... Which are parallel to the axes of the input disk 31 and the output disk 32, and the speed-change ring 34 has an axial length. This is a known ring-cone type continuously variable transmission configured to move in the direction and change the rolling contact position with the planet cones 33, 33 ...

The input disc 31 is spline-coupled to the input shaft 4 coaxially supported inside the transmission housing 30 so as to rotate integrally with the input shaft 4. The other end of the input shaft 4 is made to project to the outside of the transmission housing 30 by an appropriate length from the side opposite to the side where it is assembled to the connecting bracket 18, and the V pulley 5 fitted to this projecting end and this V pulley 5 It is connected to an output end of an engine (not shown) via a wound V belt. That is, the input shaft 4 and the input disk 31 attached thereto rotate with the rotation of the engine transmitted via the V pulley 5.

The tip of the input shaft 4 is butted against the tip of the transmission shaft 2 projecting into the transmission housing 30.
The output disc 32 is fitted onto the tip of the transmission shaft 2 via a needle roller bearing, and is rotatably supported coaxially. Further, a thick disk-shaped pressing disk 35 is spline-coupled to the protruding portion of the transmission shaft 2, and the pressing disk 35 is formed.
Is the rear side of the output disc 32, that is, the planet cones 33, 33.
It is made to face on the opposite side to the rolling contact side with.

The distance between the output disk 32 and the pressing disk 35 is
It is kept constant by the spring force of the coil spring 36 interposed between the two. The output disc 32 and the pressing disc 35 are
A cam surface inclined in the circumferential direction is provided on a predetermined circumference of a surface facing each other, and cam balls 37, 37, ... Between these cam surfaces.
Is installed. The cam balls 37, 37 ... mesh with the respective cam surfaces when the output disc 32 and the pressing disc 35 try to rotate relative to each other, and both are integrated, and at the same time, the output disc
It acts to push 32 in a direction away from the pressing disk 35, that is, in a direction to strengthen rolling contact with the planet cones 33, 33 ...

The planet cones 33, 33 ... that are in rolling contact with the input disc 31 and the output disc 32 are held by a carrier 38 having a conical annular shape with their respective axes centered on the same side.
The input disc 31 is on the inner diameter side of the bottom surface of each planet cone 33, 33 ...
The output discs 32 are also brought into rolling contact with the outer edge portions of the bottom face, respectively. That is, the transmission shaft 2 serving as an output shaft to the hydraulic pump 1.
, And the transmission from the input shaft 4 to the transmission shaft 2 is performed via the planet cones 33, 33 ...

FIG. 2 shows a ring-cone type continuously variable transmission 3
3 is an explanatory diagram of a shift principle in FIG. As shown in the drawing, the rolling contact position between the input disk 31 and the planetary cone 33 is at a distance a from the axis of the input shaft 4 and the transmission shaft 2 and b from the center of rotation of the planetary cone 33, and the transmission ring 34 and The rolling contact position with the planet cone 33 is at a distance of c from the center of rotation of the planet cone 33 and d from the axes of the input shaft 4 and the transmission shaft 2, and the output disc 32
When the rolling contact position between and the planet cone 33 is at a distance e from the center of rotation of the planet cone 33 and f from the axis of the input shaft 4 and the transmission shaft 2, the rotation speed N ₂ of the transmission shaft 2 as the output shaft is , Is represented by the following equation including the rotation speed N ₁ of the input shaft 4 under the condition that the rotation of the transmission ring 34 is restricted.

[0031]

[Equation 1]

The rolling contact position of the speed change ring 34 is the planetary cone 33.
Modified on the conical bus of the
And parallel to the axis of the transmission shaft 2. Therefore, the shift ring
The rolling contact position of 34 is changed by keeping the distance d from the axes of the input shaft 4 and the transmission shaft 2 constant, and only the distance c from the center of rotation of the planet cone 33 increases or decreases. (1) As is apparent in the expression of the time the transmission of the rotational speed N ₂ of the transmission shaft 2 under conditions of rotational speed N ₁ of the input shaft 4 is constant, i.e., the input shaft 4 to the transmission shaft 2 The gear ratio increases as the distance c decreases, and conversely decreases as the distance c increases.

For example, when c = 0, that is, when the rolling contact position of the transmission ring 34 is on the apex of the planet cone 33, the equation (1) is simplified as the following equation. N ₂ =-(ae / bf) × N ₁ (2)

This equation is an equation including only the numerical values showing the rolling contact relationship between the input disk 31 and the output disk 32 and the planetary cone 33. At this time, that is, the rolling contact position of the transmission ring 34 is When on the apex of the planet cone 33, the input shaft 4 to the transmission shaft 2
The maximum gear ratio is achieved during transmission to. N ₂ has a negative value because the rotation direction of the transmission shaft 2 is opposite to that of the input shaft 4.

On the other hand, as is clear from the equation (1),
Rotational speed N ₂ of the transmission shaft 2, the distance c is minimum (= 0) when the following expression is satisfied. c = ed / f (3)

As is apparent from the figure, the rolling contact position between the output disc 32 and the planet cone 33 is set near the periphery of the side where the inclination of the planet cone 33 is upward, and the input shaft 4 and the transmission shaft 2 are arranged. The distance f from the axis of the transmission shaft 34 is substantially equal to the distance d from the axes of the input shaft 4 and the transmission shaft 2 at the rolling contact position of the transmission ring 34.
Therefore, as shown by the broken line in FIG. 2, the gear ring 34 is provided at the rolling contact position of the output disc 32, that is, near the periphery of the planet cone 33.
When the rolling contact position of is changed, c≈e and the above (3)
The equation is approximately satisfied, and the state in which the rotation of the transmission shaft 2 is stopped can be obtained.

As described above, the rotation speed N ₂ of the transmission shaft 2 increases as the rolling contact position of the transmission ring 34 approaches the apex of the planet cone 33, and decreases as it separates. That is, the gear ratio (= N ₂ when transmitting from the input shaft 4 to the transmission shaft ₂₎
/ N ₁ ) is the rightward shift ring in FIGS. 1 and 2.
It increases in accordance with the movement of 34 and decreases in accordance with the movement to the left. Further, on this decreasing side, stepless speed change until the speed change ratio becomes zero is possible.

As shown in FIG. 1, the speed change ring 34 has a rolling contact edge with the planetary cones 33, 33, and the like facing inward at a midway portion of a cylindrical cam body 40 loosely fitted inside the transmission housing 30. It is integrally held in a projecting manner. On the inner peripheral surface of the transmission housing 30 facing the outer peripheral surface of the cam body 40, a plurality of guide keys 41, 41 ... Are fixedly arranged in the circumferential direction in a substantially equal arrangement. Has each guide key 41, 41…
Are formed at positions corresponding to the respective guide grooves 42, 42 ... And the cam body 40 is loosely fitted into the transmission housing 30 by the guide keys 41, 41. It is made to engage with. That is, the rotation of the cam body 40 and the speed change ring 34 is restricted by the transmission housing 30, and the cam body 40 and the speed change ring 34 are guided by the guide keys 41, 41 ... Only move in the axial direction within the formation range of the guide grooves 42, 42. Is possible.

One end surface of the cam body 40 is a pump housing.
.. are opposed to the outer wall surface of 14, and a plurality of coil springs 43, 43 .. These coil springs 43, 43 ...
40 is urged toward the input shaft 4 side (right side in the figure), and the other end portions of the guide grooves 42, 42 ...
It has the effect of restraining it in the state of abutting against the end of.

On the other hand, a cam surface 44 is formed on the end surface on the other side of the cam body 40 (on the input shaft 4 side). The illustrated cam surface 44 is
In the cross section including the shaft center of the input shaft 4 (and the transmission shaft 2), the inclination angle with respect to the shaft center is configured as a surface that continuously decreases toward the outer side in the radial direction. Such a cam surface 44 can be configured as, for example, a group of one circular arc or another circular arc centered on the axial center or a part of a parabola having an apex on the axial center in the cross section.

On the other hand, the input shaft 4 is provided with a plurality of support rods 45, 45, which are radially and outwardly projected from the boss portion spline-joined side by side with the input disc 31,
Pressing members 46, 46 ... Are supported on the supporting rods 45, 45.

The pressing body 46 is a spherical body made of steel having a predetermined weight, and as shown in the drawing, a fitting hole passing through the shaft center is fitted onto each of the supporting rods 45 via needle roller bearings, The support rod 45 can rotate without resistance around the axis and is supported so as to be movable in the radial direction. As described above, the support rods 45, 45 are provided on the boss portion spline-coupled to the input shaft 4 and rotate with the rotation of the input shaft 4. Therefore, the support rods 45 are supported by the support rods 45. The pressing body 46 moves outward in the radial direction by the action of the centrifugal force according to the rotation of the input shaft 4.

As shown in the drawing, the tips of the support rods 45, 45 face the cam surface 44 formed on the end surface of the cam body 40, and the pressing bodies 46, 46 ... It moves along the other support rods 45, 45, and comes into contact with the cam surface 44 from the inside in the middle of this movement path. Until this contact occurs, the cam body 40 has the guide grooves 42, 42 formed on the outer periphery.
The transmission ring 34, which is constrained in such a manner that its end surface is abutted against the guide keys 41, 41, and is integrally held by the cam body 40, of the planetary cones 33, 33, ... The rolling contact position closest to the apex is maintained on the conical generatrix, the gear ratio is maximized, and the hydraulic pump 1 is
Is driven at a speed close to the rotation speed N ₁ .

On the other hand, after the pressing bodies 46, 46 ... Abut on the cam surface 44, a centrifugal force acting on the pressing bodies 46, 46. The cam surface 44 is inclined with respect to the acting direction of the centrifugal force, and the cam surface 44 is
An axial component force of the centrifugal force of the pressing body 46 acts, and by the action of this component force, the cam body 40 moves in the axial length direction against the biasing force of the coil springs 43, 43. Coil spring 43, 43 ...
It stops at the position where the spring force of is balanced. At this time,
While the pressing bodies 46, 46 ... Rotate with the rotation of the input shaft 4, the cam surface 44 is in the non-rotation state due to the rotation restraint of the cam body 40. 46 ... are supported by respective support shafts 45, 45 ... via needle roller bearings, and can rotate without resistance accompanying rolling contact with the cam surface 44, and are pressed by the action of centrifugal force. The movement of the bodies 46, 46 ... Is performed smoothly.

As described above, the movement of the pressing bodies 46, 46 ... Is caused by the action of the centrifugal force associated with the rotation of the input shaft 4, and the cam body 40 and the speed change ring 34 integrated with the shaft are caused by the movement. Displaces in the long direction. This displacement occurs in the direction in which the rolling contact position of the speed change ring 34 is separated from the apex of each planet cone 33, 33, that is, in the direction in which the speed change ratio during transmission from the input shaft 4 to the transmission shaft 2 is reduced. Is the rotation speed N ₁ of the input shaft 4.
It will increase with decreasing, and conversely will decrease with increasing.

FIG. 3 is an enlarged view in the vicinity of the contact position between the pressing body 46 and the cam surface 44. The mechanism of generating the axial component force on the cam surface 44 will be described with reference to this drawing. The centrifugal force F acting on the pressing body 46 is decomposed into a component force F ₁ along the cam surface 44 and a component force F ₂ orthogonal to each other at the contact point with the cam surface 44, the latter being the latter. It is pressed in the axial direction by the horizontal component force F ₃ .

This horizontal component force F ₃ can be obtained by the following equation including the inclination angle θ of the cam surface 44 at the point of contact with the pressing body 46 with respect to the horizontal direction (the axial direction of the input shaft 4 and the transmission shaft 2). it can. F ₃ = F · sin θ · cos θ (4)

As is apparent from the equation (4), a constant centrifugal force F
The horizontal component force F ₃ under the action of becomes maximum when the tilt angle θ is 45 °, is substantially constant while it is within a predetermined range centered on this angle, and when it is out of this range, the tilt It sharply decreases as the angle θ decreases (or increases). In the present invention, the inclination angle θ of the cam surface 44 with respect to the axis has a distribution that becomes smaller continuously from the inner diameter side to the outer diameter side as described above. By making it sufficiently small, the rate of change of the horizontal component force F ₃ acting on the cam surface 44 sharply decreases as the contact point of the pressing body 46 moves to the outer diameter side of the cam surface 44.

The centrifugal force F is the rotational speed N of the input shaft 4.
It increases or decreases in proportion to the square of _{1 and} the contact point of the pressing body 46 is the cam surface.
It increases sharply as it moves to the outer diameter side of 44. Therefore, the horizontal component force F ₃ determined by the equation (4) can be appropriately set over the entire movement range of the pressing body 46 according to the selection of the inclination angle θ of the cam surface 44.

On the other hand, the moving distance of the cam body 40 generated by the action of the horizontal component force F ₃ as described above is such that the moving position of the pressing body 46 is the outer diameter side because the cam surface 44 has the inclination angle θ as described above. It becomes larger as you move to. Therefore, the movement of the cam body 40 and the speed change ring 34 integrated with the cam body 44 due to the pressing of the cam surface 44 by the pressing body 46 occurs while increasing the rate of change as the rotation speed N ₁ of the input shaft 4 increases. .

With the above operation, the transmission from the input shaft 4 to the transmission shaft 2 is first performed by the rotation of the input shaft 4 and pressing members 46, 46 ...
Between the start of the movement and the contact with the cam surface 44, and the axial component force F ₃ acting on the cam surface 44 after this contact is the coil spring.
Until the spring force of 43, 43 ... is exceeded, the maximum gear ratio is maintained as described above, and thereafter, the gear ratio is reduced as the input rotational speed N ₁ is increased. The reduction ratio of the gear ratio during this period increases as the input speed N ₁ increases.

Therefore, the rotation speed N _{2 of the} transmission shaft 2 which is the output shaft
Is the rotational speed N ₁ in the region where the rotational speed N ₁ of the input shaft 4 is low.
Increase with increasing ₁ but continuously reduce the increase rate at block the rotational speed N ₁ of the input shaft 4 reaches a predetermined value, a high rotational speed N ₁ of the input shaft 4 region, the rotary shows a characteristic decrease in the reverse with the increase in the number N _1, the discharge oil amount of the hydraulic pump 1 driven by the rotation of the transmission shaft 2, as shown in FIG. 4, the rotational speed N ₁ of the input shaft 4 at low area increased with the increase of the rotational speed N _1, it will exhibit characteristics that conversely decreased with the increase of the rotational speed N ₁ at high rotational speed N ₁ of the input shaft 4 region. Such a characteristic is a desirable characteristic in the hydraulic pump 1 for a power steering apparatus, as described above.

In the above embodiments, the application example of the power steering apparatus to the hydraulic pump 1 for supplying hydraulic oil has been described, but the scope of application of the present invention is not limited to this. Further, the cam surface 44 shown in this embodiment has a shape in which the inclination angle with respect to the shaft center continuously decreases from the inner diameter side to the outer diameter side, but has a shape that increases from the inner diameter side to the outer diameter side. Also, the shape may be such that these angle changes occur discontinuously, and the range of application can be expanded by adopting various different angle change forms.

Further, in the above embodiments, the use example of the continuously variable transmission 3 as the speed reducer has been described, but the continuously variable transmission 3 can also be used as the speed increasing device, and in this case as well. It goes without saying that the same effect can be obtained.

[0055]

As described in detail above, in the continuously variable transmission according to the present invention, the radial movement of the pressing body caused by the action of the centrifugal force caused by the rotation of the input side is a ring cone type continuously variable transmission. Since the shift is performed by converting the shift ring into the movement in the axial direction, the stepless shift corresponding to the increase or decrease in the input rotation speed can be reliably realized with a simple configuration, and the pressing body The cam surface for converting the movement into the movement in the axial direction of the speed change ring has different inclination angles with respect to the axial center at each position in the radial direction that is the moving direction of the pressing body. The mode of increasing the output rotation speed can be appropriately set.

Further, when the inclination angle is set to be smaller from the inner diameter side to the outer diameter side of the cam surface, in the low speed rotation range where the input rotation speed is low, the amount of change in the gear ratio with respect to the movement of the pressing body is small. Is small, and conversely, in the high-speed rotation range, the amount of change in the gear ratio with respect to the movement of the pressing body becomes large, and an auxiliary machine for an automobile that uses an engine as a drive source, such as a hydraulic pump for supplying hydraulic oil to the power steering device. Characteristics required in
That is, the present invention has an excellent effect such that the characteristic that the increase / decrease in the output rotation speed is opposite to the increase / decrease in the input rotation speed can be easily obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an application example of a continuously variable transmission according to the present invention in a transmission system of a hydraulic pump for supplying an operating hydraulic pressure to a power steering apparatus.

FIG. 2 is an explanatory diagram of a shift principle of the continuously variable transmission according to the present invention.

FIG. 3 is an enlarged view in the vicinity of a contact position between a pressing body and a cam surface for explaining a mechanism of generating an axial component force on the cam surface.

FIG. 4 is a graph showing an example of the relationship between the input rotation speed and the output rotation speed obtained by using the continuously variable transmission according to the present invention.

[Explanation of symbols]

 1 hydraulic pump 2 transmission shaft 3 continuously variable transmission 4 input shaft 10 rotor 11 cam ring 30 transmission housing 31 input disc 32 output disc 33 planetary cone 34 transmission ring 40 cam body 43 coil spring 44 cam surface 45 support rod 46 pressing body

Claims (2)

[Claims] 1. An input disc and an output disc are respectively attached to end portions of the input shaft and the output shaft, which are coaxially supported, opposite to each other, and plural outer peripheries are interposed in the circumferential direction so as to be interposed therebetween. A plurality of planetary cones are rollingly contacted with each other, and at the same time, a transmission ring is provided that is in rolling contact with the planetary cones on the respective cone generating lines parallel to the axis of the input shaft and the output shaft. In the continuously variable transmission that changes the rolling contact position with each planet cone by moving to, and can continuously change the gear ratio when transmitting from the input shaft to the output shaft, The pressing body that moves in the radial direction by the action of the accompanying centrifugal force and the cam surface in which the inclination angle in the cross section including the axis of the input shaft and the output shaft is different in the radial direction, the moving range of the pressing body. Of the cam surface by the pressing body. And a cam body for moving the speed change ring toward the deceleration side. 2. The continuously variable transmission according to claim 1, wherein the inclination angle of the cam surface is set to be smaller with respect to the shaft center from the inner diameter side to the outer diameter side.