JPH0810021B2 - Continuously variable transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a drive shaft pulley provided on a drive shaft and a driven shaft pulley provided on a driven shaft around which an endless belt is wound, and The present invention relates to a continuously variable transmission of a type in which a groove width of each pulley is changed to change a gear ratio by applying a pressure fluid to a movable pulley.

(Background of the Technology) In the continuously variable transmission described above, a drive shaft pulley and a driven shaft pulley are provided between the drive shaft and the driven shaft so that a speed ratio corresponding to an operating state of a drive source such as an internal combustion engine can be obtained. The groove width of is controlled by the pressure fluid (pressure oil) supplied from the pressure supply source (hydraulic pump). In this case, the side pressure that does not impair the power transmission efficiency even when shifting is performed at the same time as setting the groove width. Must be attached to a movable pulley.

(Problems with the prior art) Therefore, in the related art, the required side pressure is applied to the movable pulley of the driven shaft pulley, and the movable pulley of the drive shaft pulley has a constant differential pressure higher than the side pressure of the movable pulley of the driven shaft pulley during shifting. A method of controlling the pressure fluid so as to give a large or small lateral pressure with a certain amount (for example, refer to JP-A-52-98861)
Or a constant high pressure fluid and a low pressure fluid corresponding to the gear ratio etc. are set, and either the movable pulley of the drive shaft pulley or the movable pulley of the driven shaft pulley is set by the low pressure fluid. Is controlled so that the high pressure fluid flows through the movable pulley that is the pushing side of the endless belt and the low pressure fluid flows through the movable pulley that is the return side (US Pat. No. 3600961). Etc.)
Has been adopted. FIG. 6 shows the lateral pressure characteristic of the front method, and FIG. 7 shows the lateral pressure characteristic of the rear method.

However, in both of the above two types, as shown in the side pressure characteristic diagram, a side pressure higher than the required side pressure is constantly applied to one movable pulley, resulting in a large pressure loss and poor power transmission efficiency. At the same time, it is necessary to drive the hydraulic pump at a high rotation speed by using the power of the internal combustion engine, which causes a large load on the internal combustion engine and a large power loss.

Further, in the former method, since the drive shaft pulley side and the driven shaft pulley side are controlled by the same hydraulic pressure, a piston area difference corresponding to the shift load is required, and one movable pulley becomes large, and the latter method is used. However, there is a problem in that a high pressure pump is required because a high pressure fluid is used.

(Object of the Invention) The present invention has been made by paying attention to such conventional problems, and aims to reduce pressure loss, improve power transmission efficiency, and reduce power loss, and at the same time, to move the movable pulleys of both pulleys. It is an object of the present invention to provide a continuously variable transmission that can reliably change the pressure of the pressure fluid supplied to the vehicle by the pressure fluid that changes according to the gear ratio.

(Structure of the Invention) In order to achieve the above object, according to the present invention, an endless belt is wound around a drive shaft pulley provided on a drive shaft and a driven shaft pulley provided on a driven shaft. In a continuously variable transmission that is configured to change the groove width of each pulley to change the gear ratio by applying pressure fluid to the movable pulley of the pulley, the pressure supply source and the pressure fluid from this pressure supply source are used. Depending on the operating state, a low-high pressure setting unit that converts high pressure fluid and low pressure fluid respectively.
A switching valve mechanism that switches the high-pressure pressure fluid to one of the movable pulleys and supplies the high-pressure pressure fluid to the other of the movable pulleys, and a gear shift interlocking portion that generates the pressure fluid according to a gear ratio are provided. The pressure fluid generated in the speed change interlocking portion acts on the low and high pressure setting portion so that the respective pressures of the high and low pressure fluids are changed according to the pressure fluid.

(Embodiment) Each embodiment of the present invention will be specifically described below with reference to FIGS. 1 and 2. 1 shows the structure of an automatic continuously variable transmission for a vehicle to which the continuously variable transmission according to the first embodiment of the present invention is applied, and FIG. 2 shows the structure of a hydraulic control mechanism. .

In the drawing, 1 is a casing, 2 is a drive shaft, 3 is a driven shaft, 4 is a drive shaft mounted on the drive shaft 2, and a hydraulic starting clutch for transmitting the rotational power of an output shaft 6 of an internal combustion engine 5 to the drive shaft 2. , 7 is a drive shaft pulley also installed on the drive shaft 2, 8 is a driven shaft pulley installed on the driven shaft 3, and 9 is a drive shaft pulley.
Is an endless belt (steel belt) wound around the drive shaft pulley 7 and the driven shaft pulley 8 to transmit the rotational power of the drive shaft 2 to the driven shaft 3.

The starting clutch 4 includes an input side rotary body 10 that interlocks with the output shaft 6 and an output side rotary body 11 that interlocks with the drive shaft 2.
A clutch damper mechanism 12 attached to the input side rotating body 10, a pressure regulating valve control mechanism (centrifugal governor mechanism) 13 also attached to the input side rotating body 10, and an output side rotating body 11. Clutch cylinder 14, a clutch outer 15 which is also mounted on the output side rotating body 11, and a clutch piston 16 which is fitted in the clutch cylinder 14.
And a friction plate 17 mounted inside the clutch outer 15.
And is constituted by. The input side rotating body 10 is rotatably supported on the drive shaft 2 by a bearing 18, and
The outer gear 10a is meshed with the gear 6a on the output shaft 6 side. Further, the output side rotating body 11 is fitted to the drive shaft 2.

The starting clutch 4 is actuated by the pressure fluid flowing through the pressure fluid passage 19 provided in the shaft center of the drive shaft 2, and the rotation speed of the output shaft 6 becomes equal to or higher than a predetermined set value. Then, the input side rotating body 10 becomes the output side rotating body 11
To the drive shaft 2 by rotating the output shaft 6 rotationally.
It is designed to be transmitted to.

The drive shaft pulley 7 includes an on-disk fixed pulley 20 integrally formed on the outer periphery of the drive shaft 2 on the side of the starting clutch 4.
A plurality of balls that are slidable along the axial direction of the outer periphery of the drive shaft 2 so as to face the fixed pulley 20 and cannot rotate.
A movable pulley 22 supported via 21. The movable pulley 22 has a disk-shaped pulley body 22b integrally formed on the outer periphery of one end of a cylindrical boss portion 22a, and protrudes in the opposite direction to the fixed pulley 20 along the axial direction on the outer peripheral surface of the body 22b. The cylindrical peripheral wall 22c is integrally projected, and the cylindrical peripheral wall 2
A drum shape is formed by fitting an annular closing plate 22d on the inner peripheral surface of the projecting end side of 2c.

A fixed piston member 23 is fitted in the movable pulley 22. The fixed piston member 23 is formed by integrally projecting an annular flange 23b in the radial direction on the outer circumference of the other end of a cylindrical body 23a having a fitting hole at the center of one end face wall and having the other end face open. The fixed piston member 23 has a fitting hole at the center of one end wall thereof fitted in the outer peripheral surface of the drive shaft 2 so as not to be rotatable and axially movable, and the inner peripheral surface of the cylindrical body 23a is The outer peripheral surface of the flange 23b is loosely fitted to the outer peripheral surface of the boss portion 22a of the movable pulley 22, and the outer peripheral surface of the flange 23b is a cylindrical peripheral wall 2
It is fitted to the inner peripheral surface of 2c in a liquid-tight and slidable manner.

A first pressure chamber 24 is formed between the pulley body 22b of the movable pulley 2 and the flange 23b of the fixed piston member 23, and the closing plate 22d of the movable pulley 22 and the flange 23b of the fixed piston member 23 are formed. A second pressure chamber 25 is formed between them. The first and second pressure chambers 24 and 25 are formed in the pressure fluid communication passage 26 formed along the inside of the shaft center of the drive shaft 2 and the peripheral wall of the drive shaft 2 along the radial direction. It is connected to a pump 28, which will be described later, via a port 27 that is open. The flange 23b is formed with an orifice 29 that communicates the first pressure chamber 24 and the second pressure chamber 25, and the pressure fluid in the first pressure chamber 24 passes through the orifice 29. It flows into the second pressure chamber 25.

Such a drive shaft pulley 7 has the maximum groove width when in the state shown in the figure, and when the pressure fluid flows into the first pressure chamber 24 from the port 27, the movable pulley 22 moves to the fixed pulley 20 side. To reduce the groove width.

The driven shaft pulley 8 is fixed to a fixed pulley 30 integrally formed on the outer periphery of the driven shaft 3, and is slidable and rotatable on the outer periphery of the driven shaft 3 so as to face the fixed pulley 30 along the axial direction. It is composed of a movable pulley 32 which is unavoidably supported by a plurality of balls 31.

In the movable pulley 32, a disk-shaped pulley main body 32b is integrally projectingly provided on the outer circumference of one end side of a cylindrical boss portion 32a, and the main body 32b is axially provided at a substantially intermediate portion in a radial direction on a surface opposite to the fixed pulley 30 side. A cylindrical peripheral wall 32c is integrally provided along the inner peripheral surface of the cylindrical peripheral wall 32c, and an annular closing plate 32d is fitted to the inner peripheral surface of the cylindrical peripheral wall 32c on the protruding end side to form a drum shape. The cylindrical peripheral wall 32c
The inner diameter of is substantially the same as the inner diameter of the cylindrical peripheral wall 22c of the movable pulley 22 of the drive shaft pulley 7.

A fixed piston member 33 is fitted in the movable pulley 32. The fixed piston member 33 has a cylindrical body 33a having a fitting hole at the center of the wall on one end surface and an opening on the other end surface, and an annular flange 33b integrally provided on the outer circumference of the other end in the radial direction. The fixed piston member 33 has a fitting hole at the center of one end surface thereof fitted in the outer peripheral surface of the driven shaft 3 so as not to be rotatable and axially movable, and the inner peripheral surface of the cylindrical body 33a being The outer peripheral surface of the flange 33b is loosely fitted to the outer peripheral surface of the boss portion 32a of the movable pulley 32, and the outer peripheral surface of the flange 33b is a cylindrical peripheral wall 3
Liquid-tightly and slidably fitted to the inner surface of 2c.

A coil-shaped spring 34 is interposed between the opposing surfaces of the pulley body 32b of the movable pulley 32 and the flange 33b of the fixed piston member 33. The spring 34 causes the movable pulley 32 to move toward the fixed pulley 30 (with a groove width of The smaller side). The spring 34 is for applying an appropriate tension to the endless belt 9 when the internal combustion engine 5 is stopped and for setting the movable pulley 32 to the low speed side which is the initial position.

A first pressure chamber 35 is provided between the opposing surfaces of the pulley body 32b of the movable pulley 32 and the flange 33b of the fixed piston member 33, and the closing plate 32d of the movable pulley 32 and the flange of the fixed piston member 33. A second pressure chamber 36 is formed between the surfaces facing 33b. A flange 33b of the fixed piston member 33 is provided between the first and second pressure chambers 35 and 36.
Are communicated with each other via an orifice 37 formed along the axial direction.

The first pressure chamber 35 is provided with a pressure fluid passage 38 provided along the inside of the shaft center of the driven shaft 3 and a port 28 formed in the peripheral wall of the driven shaft 3 in a radial direction through a pump 28, which will be described later. Connected with.

In the vicinity of the inner end of the fixed pulley 30 of the driven shaft 3, a through hole 40 is formed in the circumferential wall along the radial direction so that the inside and the outside of the pressure fluid passage 38 can communicate with each other. The through hole 40 is opened and closed by a boss portion 32a of the movable pulley 32 as the movable pulley 32 slides on the driven shaft 3. When opened, the pressure fluid flowing through the pressure fluid communication path 41 is led out of the driven shaft 3 from the through hole 40 and the belt 9
Refuel.

When the driven shaft pulley 8 is in the state shown in the drawing, the groove width is minimum, and the pressure fluid is introduced into the first pressure chamber 35 to the maximum. Then, when the pressure fluid in the first pressure chamber 35 is discharged from the port 39, the side opposite to the fixed pulley 30 (the side where the groove width increases) can be moved against the spring 34.

The pressure fluid sent from the pump 28 is supplied to the pressure fluid passage 19 via the port 42.
26 through the port 43, into the pressure fluid passage 38 through the port 44, and into the pressure fluid passage 41 through the port 45.

In the vehicle automatic continuously variable transmission configured as described above, the rotational power of the drive shaft 2 is transmitted to the driven shaft 3 via the drive shaft pulley 7, the endless belt 9 and the driven shaft pulley 8. Then, by changing the groove widths of the drive shaft pulley 7 and the driven shaft pulley 8 by moving the movable pulleys 22 and 32 by the pressure fluid, the speed ratio can be changed steplessly.

Next, the hydraulic control mechanism 46 for controlling the groove width of the drive shaft pulley 7 and the driven shaft pulley 8 of such an automatic continuously variable transmission will be described.

The hydraulic control mechanism 46 is provided in a pressure fluid flow path system connecting the pump 28, which is a pressure supply source, and the ports 43 and 44. The hydraulic control mechanism 46 includes a low / high pressure setting unit 47 for setting the pressure fluid sent from the pump 28 to a high pressure and a low pressure with a constant differential pressure, and one of the movable pulleys 22 and 32 depending on the operating state. A switching valve mechanism 49 for supplying high-pressure pressure fluid from the low-high pressure setting section 47 to the other by switching the low-pressure pressure fluid from the low-high pressure setting section 47, and a gear change interlocking for generating pressure fluid according to the gear ratio. The pressure fluid generated in the speed change interlocking portion 48 acts on the low and high pressure setting portion 47, and the respective pressures of the high and low pressure fluids are changed according to the pressure fluid. There is. In the first embodiment, there is a constant differential pressure between the high pressure and low pressure fluids, but this differential pressure does not have to be constant.

The low / high pressure setting section 47 temporarily stores the pressure fluid sent from the pump 28 through the port 50, and the cylinder 51 which is fitted into the cylinder 51 and resists the differential pressure adjusting spring 52 by the pressure of the pressure fluid. It is configured by a differential pressure adjusting piston 53 that slides in a sliding manner. The differential pressure adjusting piston 53 has a cylindrical shape with one end closed, and is arranged in a substantially central portion of the cylinder 51 so that chambers 54 and 55 are formed on both sides of the cylinder 51. There is. Such differential pressure adjustment piston 53
When the pressure of the pressure fluid flowing into the chamber 54 via the port 50 reaches the pressure (P _A ) set by the differential pressure adjusting spring 52, the chamber is pressed against the chamber 55 and slides to open the port 56. To do. When the port 56 is opened, a part of the pressure fluid in the chamber 54 flows into the chamber 55 through the port 56, the chamber 57 and the port 58. Therefore, the pressure difference between the pressure fluid flowing into the chamber 55 and the pressure fluid inside the chamber 54 is P _A
Becomes In the illustrated case, the differential pressure adjusting piston 53 is in a differential pressure non-setting state in which the differential pressure adjusting spring 52 is not compressed, and at this time, the differential pressure adjusting piston 53 fully closes the port 56. Further, the differential pressure adjusting piston 53 is slidable in a stroke of fully opening the port 56 from the differential pressure non-setting state.

The shift interlocking unit 48 is a cylinder of the low / high pressure setting unit 47.
A sleeve that is slidably inserted into the outer peripheral surface of 51 in the axial direction.
59 and a lever for fitting the sleeve 59 into the groove 22e formed on the outer peripheral surface of the movable pulley 22 so as to interlock with the movement of the movable pulley 22, and to connect the sleeve 59 and the movable pulley 22.
And a ratio interlocking member 61 having 60, and is inserted into the sleeve 59 and pressed by the pressure of the low-pressure fluid in the chamber 55, and axially moves in the sleeve 59 against the adjusting springs 62 and 63. It is constituted by a sliding adjustment piston 64. When the pressure of the pressure fluid in the chamber 55 reaches the pressure (P _B ) set by the adjusting springs 62 and 63, the adjusting piston 64 is pushed toward the opposite chamber 55 side and slides, and is provided on the peripheral wall of the sleeve 59. Open port 65. When the port 65 is opened, a part of the pressure fluid in the chamber 55 is recovered in the oil tank 68 of the internal combustion engine through the port 65, the chamber 66 and the pressure fluid return path 67. In this case, since the sleeve 59 having the port 65 is interlocked with the displacement of the movable pulley 22, the opening amount of the port 65 changes according to the gear ratio. Therefore, the respective pressures of the high-pressure fluid and the low-pressure fluid change according to the gear ratio as shown in FIG.

The switching valve mechanism 49 is a chamber of the low / high pressure setting unit 47.
The pressure fluid flowing through the high pressure passage 70 through the rear port 69 once accommodated in 54 and the low pressure fluid flowing through the low pressure passage 71 through the rear chamber 57 having the differential pressure set are selectively supplied to the port 43. Ratio change spool valve (four-way valve) 72 to supply
And the ratio switching spool valve 72 connected to one side of the ratio switching spool valve 72 according to the throttle opening of the internal combustion engine 5.
An operating mechanism 73 for operating the 72 and an operating mechanism 74 connected to the other side of the ratio switching spool valve 72 for operating the ratio switching spool valve 72 according to the rotation speed of the internal combustion engine 5.

The high-pressure flow passage 70 is connected to one introduction port 75 of the ratio switching spool valve 72, the low-pressure flow passage 71 is connected to the other introduction port 76, and the port 43 is connected to one discharge port 77. Is connected to a supply path 78, and the other outlet port 79 is connected to a supply path 80 connected to the port 44.

The operating mechanism 73 includes a servo piston 82 slidably mounted in a cylinder 81, and a coil-shaped control spring provided between the servo piston 82 and the ratio switching spool valve 72.
83, 84, a rod 85 for operating the servo piston 82, and a rod 85 rotatably connected to the outer end of the rod 85, and the movement of the rod 85 is linked to the opening of a throttle valve (not shown) of the internal combustion engine 5. It is composed of an interlocking lever 86 for transmitting and a member 87 for supplying a pressure fluid into the cylinder 81.

The rod 85 is slidably inserted into holes 88 and 89 formed through the servo piston 82 and the member 87. The snap rings 90 and 91 attached to the front and rear ends of the servo piston 82 regulate the movement of the servo piston 82 with respect to the rod 85.

A chamber 92 is formed in the center of the hole 89 of the member 87, and the branch passage 93 of the high-pressure flow passage 70 is connected to the chamber 92 so that a high-pressure fluid is constantly supplied.

A flow path 94 through which the pressure fluid in the chamber 92 flows is formed in the axial center of the rod 85. The flow path 94 communicates with the chamber 92 through a port 95 provided at one end, and a ball 96 that closes is provided at the other end. Further, a port 98 connected to the port 97 provided on the servo piston 82 is provided on the way, and the pressure fluid flowing through the flow path 94 flows into the cylinder 85 when the ports 97 and 98 are connected, and the pressure When the pressure reaches the pressure set by the control springs 83, 84, the servo piston 82 is pressed against the opposite member 87 side against the control springs 83, 84. Therefore, in this case, an operating force in the direction of arrow (a) acts on the ratio switching spool valve 72.

In the case shown in the figure, the position of the rod 85 is such that the throttle valve is in the idle opening state, and at this time, the port 98 of the flow path 94 is not connected to the port 97 of the servo piston 82, and thus the servo piston 82 Does not move in the cylinder 85. From this state, the opening degree of the throttle valve becomes large, which causes the interlocking lever 86 to rotate in the direction of arrow (c) about the shaft 99, the rod 85 moves in the direction of arrow (a), and the snap ring 91 servos. When contacting the end face of the piston 82, the port 98 connects with the port 97. In this case, the servo piston 82 is pressed toward the opposite member 87 side by the pressure fluid as described above. Stopper 100 provided on the rod 85
The opening of the throttle valve becomes maximum when the rod 85 moves to a position slightly forward of the end surface of the member 87 that contacts the end surface of the member 87.

A decompression type centrifugal governor is used for the operation mechanism 74. The centrifugal governor uses the ratio switching spool valve 72.
The structure is controlled by the high pressure fluid discharged from the orifice 101.

That is, the centrifugal governor includes a governor shaft 104 rotatably installed in the casing via bearings 102 and 103.
A gear 105 integrally formed with the governor shaft 104, and a governor house 106 integrally formed in a direction orthogonal to the governor shaft 104.
And a cylinder 1 provided on one side in the governor house 106
It is composed of a governor weight 108 slidably fitted in 07 and a piston 110 slidably fitted in a cylinder 109 provided at the other end of the governor house 106.

The gear 105 meshes with a gear 111 installed on the drive shaft 2, so that the governor shaft 104 is interlocked with the output shaft 6 of the internal combustion engine 5.

The governor weight 108 is fitted to the end portion of the rod 112 of the piston 110, and interlocks with the piston 110. The governor weight 108 is located outside the cylinder 107 by the interposition of a coiled spring 113. The snap ring 114 prevents the rod 112 from coming off, and the snap ring 115 prevents the cylinder 107 from coming off. Therefore, the governor weight
108 is the action of spring 113 and snap ring 115 as shown.
Is in a position to abut. At this time, the piston 110 is located in the center of the cylinder 109, and the port is located above the cylinder 109.
The pressure fluid flows in through the fluid conduit 116 and the fluid conduit 117. At the axial center of the piston 110, a flow path 118 for the pressure fluid is opened at the end.
Is formed, the port 119 is
Closed when located in the middle of 9.

The port 116 is connected to the cylinder 121 of the ratio switching spool valve 72 via the supply passage 20. Therefore,
High-pressure pressure fluid in the ratio switching spool valve 72 is supplied from the orifice 101 to the centrifugal governor via the supply passage 120 and the port 116.

In such a centrifugal governor, when the governor shaft 104 rotates in conjunction with the rotation of the output shaft 6 of the internal combustion engine 5, a load Fig corresponding to the rotational state is generated by the governor weight 108 and the like. When the pressure of the high pressure fluid flowing into the upper part and acting on the piston 110 becomes the total load of the load Fig and the set load Fisp of the spring 113, the piston 1
10 is pushed and slides on the cylinder 109. As the piston 110 moves, the port 119 moves to the cylinder 10
In cooperation with 9, the pressure fluid in the cylinder 109 is discharged into the casing 1 via the flow path 118. Therefore, the piston 110
When the port 119 and the cylinder 109 are not in communication with each other, the high pressure fluid supplied to the centrifugal governor acts so as to press the ratio switching spool valve 72 in the arrow (b) direction, and the port 119 causes the cylinder 109 to move. When communicating with, the pressing force on the ratio switching spool valve 72 is weakened according to the opening state.

The switching operation of the ratio switching spool valve 72 is performed by the operation mechanism 7 described above.
The ratio change spool valve 72 is pressed in the direction of the arrow (a) by the operating force of the operating mechanism 73 that interlocks with the valve opening of the throttle valve. Operating mechanism 74 that works with rotation of shaft 6
On the contrary, the ratio change spool valve 72 is pressed in the arrow (B) direction by the operating force of. Therefore, the position where the operating force of the operating mechanisms 73 and 74 is balanced is the switching position, and
Supply paths 78 and 80 connecting the 70 and the low-pressure flow path 71 are set. When the operating force of the operating mechanism 73 overcomes the operating force of the operating mechanism 74, the high-pressure flow passage 70 causes the movable pulley 32 of the driven shaft pulley 8 to move.
Is connected to a supply passage 80 for supplying a pressure fluid to the drive shaft 22, while the low pressure passage 71 is connected to a supply passage 78 for supplying a pressure fluid to the movable pulley 22 of the drive shaft pulley 7. As a result, the driven shaft pulley 8
The groove width of the drive shaft pulley 7 is reduced, and the groove width of the drive shaft pulley 7 is expanded (state shown in the drawing). In addition, the operating force of the operating mechanism 74 is
When overcoming the operating force of 73, the high pressure passage 70 is connected to the supply passage 78 that supplies pressure fluid to the movable pulley 22 of the drive shaft pulley 7, while the low pressure passage 71 is connected to the movable pulley 32 of the driven shaft pulley 8.
Is connected to a supply passage 80 for supplying a pressure fluid to. As a result, the groove width of the drive shaft pulley 7 is reduced, and the driven shaft pulley 8
The groove width of is widened.

The ratio switching spool valve 72 is located at the center of the stroke in the illustrated case. At this position, as shown in FIG.
The high-pressure flow path 70 is connected to 8 and 80 while overlapping. That is, high-pressure pressure fluid is supplied to each of the movable pulley 22 of the drive shaft pulley 7 and the movable pulley 32 of the driven shaft pulley 8.

An orifice 122 is provided in the low-pressure flow passage 71, a branch passage 124 that branches from the flow passage 123 connecting the pump 28 and the port 50 is connected to the port 42 via a regulator valve (not shown), and connects the oil tank 68 and the chamber 66. A branch path 125 branching from the connecting return path 67 is connected. In the figure, 126 is a filter.

In the case of the example, the ratio switching spool valve 72 is an operating mechanism 73 that interlocks with the valve opening of the throttle valve of the internal combustion engine 5, and an operating mechanism (hydraulic centrifugal governor) 74 that interlocks with the rotation of the output shaft 6.
Control springs 83 and 84 of the operating mechanism 73
It is possible to freely change the switching point by changing the set loads of both the spring 113 of the operating mechanism 74.

In the first embodiment having the above configuration, when the spool valve 72 is displaced in the direction of arrow (a) in FIG.
The high pressure fluid from the movable pulley 32 of the driven shaft pulley 8
In addition to being supplied to the movable pulley 22 of the drive shaft pulley 7, the low-pressure pressure fluid from the low-high pressure setting section 47 is supplied to the movable pulley 22 of the drive shaft pulley 7. On the other hand, when the spool valve 72 is displaced in the (b) direction in FIG. 2, the high pressure fluid is moved to the movable pulley of the drive shaft pulley 7.
The low pressure fluid is supplied to the movable pulley 32 of the driven shaft pulley 8 as well as being supplied to the driven pulley 22.

As described above, the high pressure fluid is selectively supplied to one of the movable pulleys 22 and 32, and the low pressure fluid is selectively supplied to the other of the movable pulleys 22, 32, so that the gear ratio changes steplessly.

As shown in FIG. 4, the high-pressure fluid and the low-pressure fluid change in accordance with the gear ratio, that is, the pressure decreases as the gear ratio decreases, so that the pressure loss is reduced and the power transmission efficiency is reduced. As a result, the load of the pump 28 on the internal combustion engine is reduced and the power loss is reduced.

Further, according to the first embodiment described above, the hydraulic control mechanism 46
Is provided with a gear shift interlocking portion 48 that generates pressure fluid according to the gear ratio, and the pressure fluid generated in the gear shift interlocking portion 48 acts on the low and high pressure setting portion 47 to change the high pressure and the low pressure according to the pressure fluid. Since each pressure of the pressure fluid is configured to change, the movable pulleys of the both pulleys 7 and 8 from the low and high pressure setting unit 47.
The pressure of the high and low pressure fluid supplied to 22, 32,
It is possible to surely change the pressure fluid generated in the gear shift interlocking portion 48 and changing according to the gear ratio without providing a special pressure adjusting mechanism.

In addition, the control springs 83 and 84 of the operating mechanism 73 are
Since it is operated by 2, the operation load is light and the degree of freedom of the operation method is increased.

Further, since the centrifugal governor constituting the operation mechanism 74 adopts a method of controlling by the high pressure fluid discharged from the orifice 101 of the ratio switching spare valve 72, the structure is simpler and simpler than the known hydraulic centrifugal governor. Small and lightweight.

Further, an orifice is provided in the low pressure passage 71 connecting the chamber 57 of the low / high pressure setting unit 47 and the introduction port 76 of the ratio switching spool valve 72.
Since 122 is provided, the amount of the pressure fluid returned from the supply passages 78 and 80 on the side where the pressure is changed from the high pressure to the low pressure by the ratio switching spool valve 72 to the low / high pressure setting unit 47 is narrowed during the upshift and the downshift. The ratio conversion speed can be effectively controlled. Such an orifice is generally designed to be provided in both the high-pressure flow path 70 and the low-pressure flow path 71, but since the amount of the pressure fluid flowing through the high-pressure flow path 70 is also reduced, the belt tension is lowered. There is a risk. However, even when the orifice 122 is provided in the low-pressure flow passage 71 as illustrated, the pressure fluid returning from the drive shaft pulley 7 is also driven by the driven shaft pulley 8.
Since the pressure fluid returning from the high pressure passage 70 also passes through the orifice 122, the high pressure flow passage 70 can be used during both upshifting and downshifting.
The ratio conversion speed can be controlled in the same manner as in the case where orifices are provided in the low-pressure channel 71 and the low-pressure channel 71, respectively.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the first embodiment, when the sleeve 59 slides,
Since the pressure of the pressure fluid and the reaction force of the adjusting springs 62 and 63 do not directly act on the sleeve 59, but only the sliding resistance of the seal material 127 acts, the operating load is small and the lever 59
The friction between the engaging portion of the movable pulley 22 and the movable pulley 22 is small, and the braking force does not act on the movable pulley 22.
When the spring force of is increased, the operating load increases, and
There arises inconveniences such as wear of the engaging portion and application of braking force.

By the way, in the case of the speed change interlocking portion 48 in the first embodiment, the adjusting springs arranged on the outer circumference and the inner circumference of the adjusting piston 64.
Two of 62 and 63 are used to set the pressure of the pressure fluid in the chamber 55. According to this configuration, when the sleeve 59 is in the sliding state, that is, the adjusting piston 64.
There is no problem when the pressure of the pressure fluid is acting on, but when the pressure of the pressure fluid is not acting on the adjusting piston 64, a flange 128 provided on the outer circumference of the adjusting piston 64 for mounting the adjusting spring 62, The restoring force of the adjusting springs 62 and 63 makes pressure contact with the end surface 129 of the sleeve 59. Therefore, in such a case, the sleeve 59 receives the reaction force of the adjusting springs 62 and 63, and the braking force may act on the movable pulley 22. Further, in order to secure a sufficient amount of pressure fluid, the diameter of the adjusting piston 64 may be increased, but in this case, the reaction force received by the adjusting springs 62, 63 becomes large, and the set hydraulic pressure is limited. The inconvenience occurs. However, these problems can be solved by the structure of the second embodiment of the present invention shown in FIG. That is, a piston rod 131 forming a pressure fluid passage 130 penetrating in the axial direction of the adjusting piston 64 'is attached to the axial center of the adjusting piston 64', and the piston portion 132 of the piston rod 131 is attached to the cylinder 133.
A part of the pressure fluid in the chamber 55 'is introduced into the cylinder 133 through the pressure fluid passage 130. In this structure, the pressure of the pressure fluid flowing into the cylinder 133 acts on the piston portion 132, so that it is replaced by the adjusting spring 62, and thus the adjusting spring 63 'arranged on the inner circumference of the adjusting piston 64'. It is sufficient that the reaction force of the adjusting spring 63 ′ acts on the sleeve 59 ′ even when the pressure of the pressure fluid does not act on the adjusting piston 64 ′ because there is no protruding portion on the outer circumference of the adjusting piston 64 ′. There is no. Therefore, there is an advantage that the operation load of the sleeve 59 ′ is small, the engagement portion between the lever 60 and the movable pulley 22 is less worn, and the movable pulley 22 is not subjected to a braking force.

Further, by providing the cylinder 133 which communicates with the chamber 55 ′ through the pressure fluid passage 130, it is possible to secure a sufficient amount of the pressure fluid in the chamber 55 ′ without increasing the diameter of the adjusting piston 64 ′. it can.

(Effect of the Invention) As described in detail above, in the continuously variable transmission according to the present invention, the endless belt is provided on the drive shaft pulley provided on the drive shaft and the driven shaft pulley provided on the driven shaft. In a continuously variable transmission which is wound around and configured to change the gear ratio by changing the groove width of each pulley by applying a pressure fluid to the movable pulley of each pulley, a pressure supply source and this pressure A low-high pressure setting unit for converting the pressure fluid from the supply source into a high-pressure pressure fluid and a low-pressure pressure fluid, respectively,
A switching valve mechanism that supplies the high pressure fluid to one of the movable pulleys and the low pressure fluid to the other in accordance with the operating state, and a gear shift interlocking mechanism that generates the pressure fluid according to the gear ratio. And a pressure fluid generated in the speed change interlocking portion acts on the low and high pressure setting portion so that each pressure of the high pressure and low pressure fluids changes according to the pressure fluid. , The high-pressure pressure according to the gear ratio is supplied to one of the two movable pulleys, and the low-pressure fluid is supplied to the other by switching the low-pressure fluid so that the gear ratio changes steplessly, reducing pressure loss and transmitting power. In addition, the load of the pressure supply source on the internal combustion engine is reduced, power loss is reduced, a high-pressure pump is not required as a pressure supply source, and one of the movable pulleys does not become large. Further, a gear shift interlocking portion for generating a pressure fluid according to the gear ratio is provided, and the pressure fluid generated in the gear shift interlocking portion acts on the low / high pressure setting portion to produce the high pressure and low pressure pressure fluids according to the pressure fluid. The pressure of the high-pressure and low-pressure fluid supplied from the low-high pressure setting section to the movable pulleys of both pulleys is
It is possible to surely change the pressure fluid that is generated in the gear shift interlocking portion and that changes according to the gear ratio without providing a special pressure adjusting mechanism.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of an automatic continuously variable transmission for a vehicle to which a continuously variable transmission according to a first embodiment of the present invention is applied,
2 is a sectional view showing a hydraulic control mechanism of the transmission shown in FIG. 1, FIG. 3 is a sectional view showing a hydraulic control mechanism of a continuously variable transmission according to a second embodiment of the present invention, and FIG. Is a diagram showing the relationship between the high pressure fluid and the low pressure fluid obtained in the first embodiment, and FIG. 5 is the low pressure fluid of the high pressure fluid switched by the ratio switching spool valve of the hydraulic control mechanism shown in FIG. 6 and 7 are diagrams showing the relationship of the pressure fluid in FIG.
Each of the figures is a lateral pressure characteristic diagram of a conventional continuously variable transmission. 2 ... drive shaft, 3 ... driven shaft, 5 ... internal combustion engine, 7 ...
Drive shaft pulley, 8 ... driven shaft pulley, 9 ... endless belt, 22 ... movable pulley, 28 ... pump (pressure fluid supply source), 32 ... movable pulley, 46 ... control device, 47 ... low High-voltage setting part, 48 ... Gear change interlocking part, 49 ... Switching valve mechanism, 59, 5
9 '... sleeve, 62, 63, 63' ... adjusting spring, 64, 64 '...
… Adjusting piston, 65… Port, 70… High-pressure passage, 71…
… Low pressure flow path.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-52-98861 (JP, A) JP-A-56-134658 (JP, A) JP-B-58-29424 (JP, B2)

Claims (1)

[Claims] 1. An endless belt is wound around a drive shaft pulley provided on a drive shaft and a driven shaft pulley provided on a driven shaft, and a pressure fluid is applied to a movable pulley of each pulley. In a continuously variable transmission that is configured to change the gear ratio by changing the groove width of each pulley, a pressure supply source and pressure fluid from this pressure supply source are converted into a high pressure fluid and a low pressure fluid. A low / high pressure setting unit for converting each, a switching valve mechanism for switching and supplying the high pressure pressure fluid to one of the movable pulleys and the other low pressure pressure fluid to the other according to an operating state, and a gear ratio. A pressure interlocking portion that generates a pressure fluid according to the pressure fluid, and the pressure fluid generated in the gearshift interlocking portion acts on the low-high pressure setting portion to change the pressures of the high-pressure and low-pressure pressure fluids according to the pressure fluid. To change Continuously variable transmission, characterized in that it is.