JP3008066B2 - Continuously variable transmission - Google Patents

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 for use in, for example, a transmission system of various automotive accessories driven by an engine.

[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 generator for charging a battery, and a compressor for air conditioning. 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 kind of auxiliary equipment, there is a problem that a large power loss is caused during high-speed operation with a high engine rotation speed. When the specifications of the auxiliary equipment are determined to keep the level low, there is a problem that the capacity of each auxiliary equipment becomes insufficient during low-speed operation. Therefore, conventionally, a transmission has been interposed in the middle of the transmission system to each auxiliary device, and the transmission ratio of the transmission has been changed according to the level of the input rotation speed from the engine. When the input rotation speed is high, the signal is transmitted to the auxiliary machine after a predetermined deceleration, so that the above-described problem is solved.

As the transmission, a continuously variable transmission capable of continuously changing the speed is used in many cases. This is to prevent a sudden change in the engine load due to the above-described change in the gear ratio, and to prevent the running stability from deteriorating. The change of the gear ratio in the transmission is generally realized by a structure in which an input rotation speed from an engine is detected, and a shift actuator is operated based on the detection result.
However, in this case, the overall configuration of the transmission becomes complicated,
As a result, it is difficult to secure an installation space in the middle of the transmission system from the engine, and there is a risk of malfunction due to external noise.

That is, a desirable configuration of a transmission used in a transmission system of an auxiliary machine for an automobile is that a gear ratio can be changed in a stepless manner by simple mechanical means in accordance with the level of an input rotation speed. There is a continuously variable transmission which has made this possible, as disclosed in Japanese Patent Application Laid-Open Nos. 63-82876 and 61-228155.
Nos. 3 and 4, respectively.

The continuously variable transmission disclosed in Japanese Patent Application Laid-Open No. 63-82876 has been proposed as an example of application to a hydraulic pump for supplying hydraulic oil to a power steering device, and an input shaft from an engine is provided. And the output shaft to the hydraulic pump are connected via a variable pitch pulley that changes the gear ratio by changing the effective diameter, while a steel ball is arranged outside the conical half that constitutes the variable pitch pulley on the output shaft side. The steel ball moves radially outward by the action of centrifugal force accompanying the rotation of the output shaft, and presses the half inward, that is, in a direction to approach the other half. .

According to this configuration, the effective diameter of the variable pitch pulley on the output shaft side increases due to the approach of the halves in accordance with the movement of the steel ball, while the movement of the steel ball depends on the rotation speed of the output shaft. Since this occurs with an increase, the speed ratio from the input shaft to the output shaft is steplessly changed to the deceleration side with an increase in the rotation speed of the output shaft.

The continuously variable transmission disclosed in Japanese Patent Application Laid-Open No. 61-228155 basically includes an input disk on the input side from the engine and an output disk on the output side to the auxiliary machine. , While being brought into contact with a plurality of planetary cones in the circumferential direction interposed between them, these planetary cones are rolled together on respective conical generatrix parallel to the axis of the input disk and the output disk. A speed change ring is provided for contact with the planetary cone, and the speed change ratio during transmission from the input side to the output side can be continuously changed. A ring cone type continuously variable transmission, a centrifugal force drive gear pivotally supported on a predetermined circumference centered on the axis, and an annular cam member having an internal gear meshing with the outside thereof. And a roller key protruding from the transmission ring is rolled on the cam surface of the cam member. And it has a meta configuration.

In this configuration, when the centrifugal force driving gear rotates around the pivot shaft, the cam member meshing therewith rotates via the internal gear, the transmission ring is pressed via the roller key, and the shaft length is increased. The shift is performed by moving in the direction. The centrifugal force drive gear is provided with a weight portion eccentric from the pivot shaft at one location in the circumferential direction, and the weight portion is radially moved by centrifugal force acting according to rotation on the arrangement circumference. Rotate around the pivot axis to be outside. Therefore, the speed ratio from the input side to the output side is steplessly changed to the deceleration side with an increase in the rotation speed on the output side.

[0010]

The problem to be solved by the present invention is disclosed in 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 or decreased in accordance with 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 and the moving force of the steel ball is required. Is not enough. That is, JP-A-63-828
The continuously variable transmission disclosed in Japanese Patent Publication No. 76 has a problem that it is difficult to realize a shift operation and lacks practicality.

On the other hand, in the continuously variable transmission disclosed in Japanese Patent Application Laid-Open No. 61-228155, a large force is not required to move the speed change ring in the axial direction for speed change. The operation is performed without any trouble. However, precise parts that require high processing accuracy, such as a cam member having an internal gear and a centrifugal drive gear that meshes with the cam member, are required, and the processing and assembly of these parts require a large number of man-hours. There is.

In addition, the conventional continuously variable transmission configured as described above performs a shift in accordance with an increase or decrease in the output-side rotational speed. It is not possible to obtain a characteristic that is opposite to that on the side, that is, a characteristic that the output rotational speed decreases as the input rotational speed from the engine increases. In some cases.

For example, in a hydraulic pump for supplying hydraulic oil for a power steering device, a road surface reaction force acting on steering wheels is small during high-speed running, and almost no steering assist force is required. It is sufficient to supply a smaller amount of oil than at 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 an increase in the engine rotational speed on the input side, but only increases while decreasing the rate of increase. In other words, during high-speed operation, the hydraulic pump is driven at a high rotational speed to supply unnecessary hydraulic oil that is not used for assisting steering. It is known that the power consumption of a hydraulic pump is substantially proportional to the cube of the number of revolutions. Therefore, the power loss of the engine due to the generation of the useless hydraulic oil described above is large, and the driving performance and the fuel consumption of the automobile are deteriorated. Invite you.

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

The present invention has been made in view of the above circumstances, and it is possible to surely realize a stepless speed change in accordance with an increase or decrease in the input rotation speed with a simple configuration, 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 a mode can be appropriately set, and a characteristic in which an increase or decrease in an output rotational speed is opposite to an increase or decrease in an input rotational speed is obtained. Aim.

[0016]

A continuously variable transmission according to the present invention has an input disk and an output disk attached to ends of an input shaft and an output shaft which are coaxially supported and opposed to each other. While each outer periphery is rolled and contacted with a plurality of planetary cones in the circumferential direction interposed between them, the planetary cones are collectively formed on the respective cone generating lines parallel to the axis of the input shaft and the output shaft. A speed change ring is provided for rolling contact, and the position of the speed change ring in contact with each planet cone is changed by moving the speed change ring in the axial direction so that the speed ratio at the time of 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 due to the action of the centrifugal force accompanying the rotation of the input shaft, and the inclination angle in the cross section including the axis of the input shaft and the output shaft is changed in the radial direction. Facing the moving area of the pressing body. 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.

Further, the inclination angle of the cam surface is set to be smaller with respect to the axis 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 the moving area. Moves in the axial direction, and the speed is shifted to the reduction side. At this time, the speed ratio at the time of transmission from the input shaft to the output shaft changes according to the increase or decrease of the input-side rotational speed, and is determined irrespective of the output-side rotational speed. Further, the cam surface has a different inclination angle in a radial direction which is a 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. Changes depending on the change in the inclination angle of the cam surface, and the change in 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 a low speed rotation region 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 is performed on the outer diameter side, the amount of change in the speed ratio with respect to the movement of the pressing body is large, and the rotation speed of the output shaft is smaller than the input speed. While the rotation speed of the shaft is low, it is kept high, while the rotation speed of the input shaft is sharply reduced as the rotation speed is increased, so that the output rotation speed is increased or decreased in reverse to 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 longitudinal sectional view showing an application example of a continuously variable transmission according to the present invention to a hydraulic pump for supplying a working hydraulic pressure to a power steering device.

The illustrated hydraulic pump 1 has a short cylindrical rotor 10 for holding a plurality of vanes movably in a radial direction.
And a cam ring 11 having an uneven thickness annular shape. The cam ring 11 is housed inside a pump housing 14 together with a pressure plate 12 coaxially positioned on one side thereof, and an end plate 13 for closing the other side of the pump housing 14 and the pressure plate 12.
And fixed between them. Further, the rotor 10 is loosely fitted inside the cam ring 11 and the pressure plate 12
Through the shaft center of cam ring 11 and end plate
The front end of the transmission shaft 13 is fitted to the supported transmission shaft 2, and rotates coaxially inside the cam ring 11 in accordance with the rotation of the transmission shaft 2.

The above-described hydraulic pump 1 operates to generate hydraulic pressure in a plurality of pump chambers arranged in the circumferential direction between the outer periphery of the rotor 10 and the inner periphery of the cam ring 11. These pump chambers are provided with an end plate 13 and a pump housing
The pressure pipe 17 communicates with a discharge pipe (not shown) through a pressure chamber 17 formed on the rear side of the pressure plate 12.

The suction pipe 15 is connected to an oil tank (not shown) for storing the hydraulic oil of the power steering device. When the rotor 10 is rotated by the rotation of the transmission shaft 2, the suction pipe 15 is connected to each pump chamber outside the rotor 10. The hydraulic 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, rotate along with the rotor 10 while moving forward and backward in the radial direction following irregularities on the inner periphery, and rotate with each pump chamber. The hydraulic oil introduced into the pump is sealed between the adjacent vanes, rotated with the rotor 10 to increase the pressure, and supplied to the power steering device via the pressure chamber 17 and the discharge pipe.

The pump housing 14 includes an end plate 13
The coupling bracket 18 is provided with a cylindrical coupling bracket 18 protruding coaxially on the opposite side of the closing portion of the transmission housing 30 which is coaxially mounted on the end face of the coupling bracket 18 according to the present invention. The transmission 3 is configured.

The continuously variable transmission 3 includes an input disk 31 and an output disk.
The outer periphery of each of the planetary cones 32 is rolled in contact with the bottom surface of a plurality (only two are shown) of the planetary cones 33, 33,... An annular transmission ring 34 is rolled together on the conical generatrix of each of the planetary cones 33, 33,... Parallel to the axis of the input disk 31 and the output disk 32. This is a known ring-cone type continuously variable transmission configured to shift by changing the rolling contact position with the planetary cones 33, 33.

The input disk 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 protrudes out of the transmission housing 30 from the side opposite to the side where the input shaft 4 is assembled to the connection bracket 18, and has a V-pulley 5 fitted to this protruding end and a 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 through the V pulley 5.

The tip of the input shaft 4 is in contact with the tip of the transmission shaft 2 projecting into the transmission housing 30,
The output disk 32 is externally fitted to the distal end of the transmission shaft 2 via a needle roller bearing, and is rotatably supported coaxially. A thick disk-shaped pressing disk 35 is spline-coupled to the projecting portion of the transmission shaft 2.
Is the back side of the output disk 32, that is, the planetary cones 33, 33
… And the opposite side.

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 them. The output disk 32 and the pressing disk 35 are
A cam surface inclined in the circumferential direction is provided on a predetermined circumference of a surface facing each of them, and between these cam surfaces, cam balls 37, 37,.
Is interposed. The cam balls 37, 37 ... mesh with the respective cam surfaces when the output disk 32 and the pressing disk 35 are about to rotate relative to each other, so that the two are integrated and the output disk is
32 is pressed away from the pressing disk 35, that is, in a direction for enhancing the rolling contact with the planetary cones 33, 33,.

The planetary cones 33, 33,... Which are in rolling contact with the input disk 31 and the output disk 32 are held by a carrier 38 having a conical annular shape with their respective axes inclined to the same side.
The input disk 31 is located on the inner diameter side of the bottom of each of the planetary cones 33, 33 ...
The output disks 32 are also rolled on the outer edges of the bottom surface. That is, the transmission shaft 2 serving as an output shaft to the hydraulic pump 1
The transmission from the input shaft 4 to the transmission shaft 2 is performed via the planetary cones 33, 33,.

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

[0031]

(Equation 1)

The rolling contact position of the speed change ring 34 is
On the input shaft 4
And parallel to the axis of the transmission shaft 2. Therefore, the transmission ring
The change of the rolling contact position of 34 is performed while keeping the distance d from the axis of the input shaft 4 and the transmission shaft 2 constant, and only the distance c from the rotation center of the planetary 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 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 vertex of the planetary cone 33, the equation (1) is simplified as follows. N ₂ = − (ae / bf) × N ₁ (2)

This equation includes only a numerical value indicating a 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 it is on the vertex of the planetary cone 33, the input shaft 4
The transmission gear ratio at the time of transmission to the transmission becomes maximum. Incidentally, the N ₂ is 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 apparent from the above 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 drawing, the rolling contact position between the output disk 32 and the planetary cone 33 is set near the periphery of the side where the inclination of the planetary cone 33 is upward, and the input shaft 4 and the transmission shaft 2 Is substantially equal to the distance d from the axis 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 speed change ring 34 is located at the rolling contact position of the output disk 32, that is, near the periphery of the planetary cone 33.
When the rolling contact position is changed, c ≒ e, and the above (3)
The formula is approximately established, and a 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 planetary cone 33 and decreases as it separates. That is, the gear ratio (= N _{2) at the time} of transmission from the input shaft 4 to the transmission shaft ₂
/ N ₁ ) is the rightward shifting ring in FIGS. 1 and 2
It increases with the movement of 34 and decreases with the movement to the left, and further, on this decreasing side, stepless shifting is possible until the gear ratio becomes zero.

As shown in FIG. 1, the transmission ring 34 is provided with a rolling contact edge with the planetary cones 33, 33 inward in the middle of a cylindrical cam body 40 loosely fitted inside the transmission housing 30. They are integrally held in a projecting manner. A plurality of guide keys 41 are fixed on the inner peripheral surface of the transmission housing 30 facing the outer peripheral surface of the cam body 40 so as to be substantially equally arranged in the circumferential direction. Each of the guide keys 41, 41 ...
Are formed at the positions corresponding to the guide grooves 41, 42, respectively. The loose fit of the cam body 40 into the transmission housing 30 corresponds to the guide keys 41, 41,. It is made to engage with. That is, the cam body 40 and the speed change ring 34 are restricted from rotating by the transmission housing 30 and are guided by the guide keys 41, 41 and move only in the axial length direction within the formation range of the guide grooves 42, 42. Is possible.

One end surface of the cam body 40 is connected to the pump housing.
A plurality of coil springs 43, 43,... Are interposed between these opposing surfaces in the circumferential direction at equal intervals. These coil springs 43, 43 ...
40 is urged toward the input shaft 4 side (right side in the figure), and the other end of the guide grooves 42, 42,.
And acts to restrict the state of contact with the end.

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

On the other hand, the input shaft 4 is provided with a plurality of support rods 45, 45 projecting radially outward from a boss portion which is arranged on the input disk 31 and spline-connected, and radially outward.
Each of these support rods 45, 45 ... supports a pressing body 46, 46 ....

The pressing body 46 is a steel sphere having a predetermined weight. As shown in the figure, a fitting hole passing through the axis is fitted to each of the other supporting rods 45 via a needle roller bearing. The support rod 45 is rotatable around the axis without any resistance, and is supported so as to be movable in the radial direction. As described above, the support rods 45 are projected from the boss portion spline-coupled to the input shaft 4 and rotate with the rotation of the input shaft 4, so that the support rods 45 are supported by the support rods 45. The pressing body 46 moves radially outward by the action of centrifugal force according to the rotation of the input shaft 4.

As shown in the drawing, the tips of the support rods 45 face the cam surface 44 formed on the end face of the cam body 40, and the pressing bodies 46, 46 ... It moves along the other support rods 45, 45, and contacts the cam surface 44 from the inside in the middle of this movement path. Until this contact occurs, the cam body 40 is guided by the guide grooves 42, 42 formed on the outer periphery.
Are held in a state in which the end faces of the gears abut against the guide keys 41, 41, and the speed change ring 34 integrally held by the cam body 40, as shown in FIG. On the conical generating line, the rolling contact position closest to the apex is maintained, the gear ratio becomes maximum, and the hydraulic pump 1
It is driven by a speed near the speed N _1.

On the other hand, after the pressing members 46 contact the cam surface 44, a centrifugal force acting on the pressing members 46, 46 is applied to the cam surface 44 in a radially outward direction. The cam surface 44 is inclined with respect to the direction of action of the centrifugal force.
The axial component of the centrifugal force of the pressing body 46 acts, and by the action of this component, the cam body 40 moves in the axial direction against the urging force of the coil springs 43, 43. Coil spring 43, 43…
Stops at a position where the spring force of the motor is balanced. At this time,
While the pressing members 46, 46,... Rotate with the rotation of the input shaft 4, the cam surface 44 is in a non-rotating state due to the rotation restriction of the cam member 40, but as described above, the pressing members 46, 46,. 46 ... are supported by respective support shafts 45, 45 ... via needle roller bearings, and can rotate without resistance with 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 members 46, 46... Is caused by the action of the centrifugal force accompanying the rotation of the input shaft 4, and the cam member 40 and the transmission ring 34 integrated therewith are driven by the movement. Displaced in the longitudinal direction. This displacement occurs in a direction in which the rolling contact position of the transmission ring 34 is separated from the apex of each of the planetary cones 33, 33, that is, in a direction in which the transmission ratio at the time of transmission from the input shaft 4 to the transmission shaft 2 is reduced. Is the rotation speed N ₁ of the input shaft 4
Will increase with the decrease of the number, and will decrease with the increase.

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

The horizontal component F ₃ can be obtained by the following equation including the inclination angle θ of the cam surface 44 at the contact point with the pressing body 46 with respect to the horizontal direction (the axial length 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 equation (4), a constant centrifugal force F
The horizontal component force F ₃ under the action of (1) is maximum when the inclination angle θ is 45 °, is substantially constant while being within a predetermined range centered on this angle, and when the inclination angle θ is out of this range, the inclination is It decreases rapidly as the angle θ decreases (or increases). In the present invention, as described above, the inclination angle θ of the cam surface 44 with respect to the axis has a distribution such that the inclination angle θ continuously decreases from the inner diameter side to the outer diameter side. by sufficiently small, the change rate of the horizontal force F ₃ acting on the cam surface 44, the contact point of the pressing body 46 will sharply with the move to the outer diameter side of the cam surface 44.

The centrifugal force F is the number of revolutions 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
It increases rapidly as it moves to the outside diameter side of 44. Therefore, (4) horizontal force F ₃ which is determined by the formula can be suitably set over the entire range of movement of the pressing body 46 in accordance with the selection of the inclination angle θ of the cam surface 44.

On the other hand, the moving distance of the cam body 40 caused 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 on the outer diameter side since the cam surface 44 has the inclination angle θ as described above. It becomes big as it moves to. Resulting Thus, movement of the control ring 34 that is integrated cam body 40, and that this caused the pressing of the cam face 44 by the pressing member 46, while increasing the rate of change with an increase of the rotational speed N ₁ of the input shaft 4 .

By the above operation, the transmission from the input shaft 4 to the transmission shaft 2 is performed by pressing the pressing members 46, 46,.
There between until it abuts against the cam surface 44 begins to move, and the axial component force F ₃ is a coil spring acting on the abutment post cam surface 44
Between by more than 43, 43 ... spring force to keep the maximum speed ratio as described above, after this, it will be performed while reducing the transmission ratio with increasing input rotational speed N _1, further , the reduction rate during this period of the gear ratio increases with increase in the input rotational speed N _1.

Therefore, the rotation speed N _{2 of the} transmission shaft 2 as the output shaft is
In a region where the rotation speed N ₁ of the input shaft 4 is low, the rotation speed N ₁
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 characteristics are desirable characteristics in the hydraulic pump 1 for a power steering device as described above.

In the above embodiment, an example in which the power steering device is applied to the hydraulic pump 1 for supplying hydraulic oil has been described, but the scope of the present invention is not limited to this. In addition, the cam surface 44 shown in the present embodiment has a shape in which the inclination angle with respect to the axis is continuously reduced 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. Alternatively, 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 modes.

Further, in the above embodiment, the example of using the continuously variable transmission 3 as a speed reducer has been described. However, the continuously variable transmission 3 can also be used as a speed increasing device. It goes without saying that a similar effect can be obtained.

[0055]

As described above in detail, 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 accompanying the rotation on the input side is a ring cone type continuously variable transmission. The speed change is performed by converting the speed of the speed change ring into the movement in the axial direction of the speed change ring, so that the stepless speed change according to the increase or decrease of the input rotation speed can be reliably realized with a simple configuration. Since the cam surface for converting the movement into the movement of the speed change ring in the axial direction has a different inclination angle with respect to the axis at each radial position that is the moving direction of the pressing body, the input rotation speed is increased. A corresponding increase mode of 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 a low-speed rotation region where the input rotation speed is low, the change amount of the speed ratio with respect to the movement of the pressing body is small. On the other hand, in the high-speed rotation range, the change ratio of the gear ratio with respect to the movement of the pressing body becomes large, and an auxiliary device for an automobile driven by an engine such as a hydraulic pump for supplying hydraulic oil to a power steering device. Characteristics required in
That is, the present invention has excellent effects, such as easily obtaining a characteristic in which the increase and decrease in the output rotational speed is opposite to the increase and decrease in the input rotational speed.

[Brief description of the drawings]

FIG. 1 is a longitudinal 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 a working hydraulic pressure to a power steering device.

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 of the vicinity of a contact position between the pressing body and the 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 a relationship between an input rotation speed and an output rotation speed obtained by using the continuously variable transmission according to the present invention.

[Explanation of symbols]

 DESCRIPTION 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 disk 32 Output disk 33 Planet cone 34 Transmission ring 40 Cam body 43 Coil spring 44 Cam surface 45 Support rod 46 Pressing body

Continuation of the front page (56) References JP-A-4-125347 (JP, A) JP-A-4-60247 (JP, A) JP-A-2-248749 (JP, A) Japanese Utility Model Application No. Sho 61-77456 (JP) U.S. Pat. No. 5,484,346 (US, A) German Patent Invention 44,993 (DE, C2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 15/52 F02B 9/02 B62D 5/07

Claims (2)

(57) [Claims] An input disk and an output disk are respectively mounted on ends of an input shaft and an output shaft which are coaxially supported and opposed to each other, and a plurality of outer circumferences are provided in a circumferential direction interposed therebetween. A transmission ring which, while being in contact with the plurality of planetary cones, is brought into contact with the planetary cones collectively on respective conical generatrix parallel to the axis of the input shaft and the output shaft, in the axial direction of the transmission ring. In the continuously variable transmission that changes the rolling contact position with each planetary cone by moving to the input shaft and allows the gear ratio at the time of transmission from the input shaft to the output shaft to be changed steplessly, the rotation of the input shaft is The pressing body that moves in the radial direction due to 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 varied in the radial direction is the moving area of the pressing body. In response to the pressing of the cam surface by the pressing body. And a cam body for moving the speed change ring to the speed reduction 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 axis from the inner diameter side to the outer diameter side.