JP7399558B2 - hydraulic circuit - Google Patents

Description

The present invention relates to a hydraulic circuit.

A belt-type continuously variable transmission (CVT) is known as a transmission installed in vehicles such as automobiles.

A belt-type continuously variable transmission has a configuration in which an endless belt is wound around a primary pulley and a secondary pulley. The primary pulley and the secondary pulley each have a fixed sheave that is fixedly supported on the rotating shaft, and a fixed sheave that is movable in the axial direction of the rotating shaft and non-rotatably supported, and faces the fixed sheave with a belt interposed therebetween. It is equipped with a movable sheave. When power from the engine is input to the rotating shaft of the primary pulley, the power is transmitted from the primary pulley to the belt, and from the belt to the secondary pulley. Further, as each movable sheave of the primary pulley and the secondary pulley moves, the winding diameter of the belt around the primary pulley and the secondary pulley changes, and the gear ratio (pulley ratio) changes continuously and steplessly.

For vehicles equipped with a belt-type continuously variable transmission, for example, when the vehicle passes over a protrusion such as a speed breaker (speed bump), or when the drive wheels regain grip from a state where they have slipped on the road surface. Furthermore, belt slippage may occur between the pulley and the belt. In other words, when the vehicle's drive wheels lift off the road surface when going over a protrusion, or the drive wheels slip on the road surface, the rotation speed of the output shaft increases, and then the drive wheels grip the road surface. Sometimes, the rotational speed of the output shaft suddenly decreases due to the torque input from the road surface to the drive wheels, and the belt may slip against the pulley due to the inertia torque caused by this sudden decrease.

In order to prevent belt slippage, a clutch is installed on the power transmission path between the secondary pulley and the drive wheel, and the transmission torque capacity of the clutch (clutch torque capacity) is made smaller than the transmission torque capacity of the belt (belt torque capacity). A technique has been proposed to set the value smaller. If the clutch torque capacity is smaller than the belt torque capacity, the clutch will slip before the belt when excessive torque is input from the road surface to the drive wheels, thereby preventing belt slippage.

Japanese Patent Application Publication No. 4-231765 Japanese Patent Application Publication No. 2000-193081

However, depending on the hydraulic circuit that supplies hydraulic pressure to the clutch, a configuration is adopted in which a constant pressure is supplied to the engaged clutch to maintain the engaged state. In a hydraulic circuit employing this configuration, the hydraulic pressure supplied to the engaged clutch cannot be increased or decreased, and the clutch torque capacity cannot be increased or decreased. Therefore, the hydraulic circuit cannot be used in a continuously variable transmission that employs control (clutch fuse control) that prevents belt slippage by making the clutch torque capacity smaller than the belt torque capacity.

An object of the present invention is to provide a hydraulic circuit that can be suitably used in a belt-type continuously variable transmission that employs clutch fuse control.

In order to achieve the above object, the hydraulic circuit according to the present invention is a hydraulic circuit for a transmission equipped with an engagement element, which receives a source pressure and regulates the input source pressure to a predetermined modulator pressure. a solenoid valve that receives the modulator pressure output from the modulator valve, regulates the input modulator pressure to an engagement pressure that engages the engagement element, and outputs it; and an output from the modulator valve. A modulator pressure input port into which the modulator pressure to be applied is input, an engagement pressure input port into which the engagement pressure output from the solenoid valve is input, and a spool movable between a control position and a fail position. When the spool is in the control position, the engagement pressure input to the engagement pressure input port is output as hydraulic pressure supplied to the engagement element, and when the spool is in the fail position, it is input to the modulator pressure input port. The shift valve outputs the modulator pressure to be supplied as hydraulic pressure to the engagement element, and the modulator pressure output from the modulator valve is input, outputs the input modulator pressure in the on state, and outputs the modulator pressure in the off state. and an on/off valve that stops the output of the engagement element and is turned on for the engagement transient and engagement hold of the engagement element, and the shift valve includes an on/off valve that is inputted with the modulator pressure output from the on/off valve. The spool is located at the control position when the modulator pressure is input, and the spool is located at the fail position when the modulator pressure is not input.

According to this configuration, the source pressure is input to the modulator valve, and the modulator valve regulates the source pressure to the modulator pressure and outputs the modulator pressure. The modulator pressure output from the modulator valve is input to the solenoid valve, and the solenoid valve regulates the modulator pressure to an engagement pressure and outputs it. The modulator pressure output from the modulator valve is input to the on/off valve.

When the on/off valve is in the on state, modulator pressure is output from the on/off valve, the modulator pressure is input to the shift valve, and the spool of the shift valve is located in the control position. In this state, the engagement pressure output from the solenoid valve is input to the engagement pressure input port of the shift valve, and the engagement pressure is output from the shift valve and supplied to the engagement element.

The engagement pressure can be increased or decreased by controlling the energization of the solenoid valve. The transmission torque capacity of the engagement element can be increased or decreased by increasing or decreasing the engagement pressure. Therefore, this hydraulic circuit is suitable for a continuously variable transmission that employs clutch fuse control that prevents belt slippage by making the transmission torque capacity of the engagement element smaller than the transmission torque capacity of the belt of the continuously variable transmission mechanism. It can be used for.

On the other hand, when the on/off valve is in the off state, output of the modulator pressure from the on/off valve is stopped, so no modulator pressure is input from the on/off valve to the shift valve. Therefore, the spool is located at the fail position. In this state, the modulator pressure output from the modulator valve is input to the modulator pressure input port, and the modulator pressure is supplied to the engagement element.

If a power loss failure occurs, the on/off valve is turned off, so modulator pressure is supplied from the shift valve to the engagement element. This causes the engagement elements to engage. Therefore, even if the engagement element is a clutch that transmits/cuts off the power for driving the vehicle, when a failure due to power loss occurs, the clutch becomes engaged, so there is no power from the transmission for driving the vehicle. of power can be output, and the running of the vehicle can be ensured.

It is preferable that the modulator valve has a feedback port into which the engagement pressure supplied to the engagement element is input, and has a configuration in which the modulator pressure is reduced in accordance with the engagement pressure input to the feedback port. .

As a result, the modulator pressure input to the solenoid valve is reduced, so the differential pressure between the modulator pressure and the engagement pressure output from the solenoid valve can be reduced, and the override characteristics of the solenoid valve can be improved.

According to the present invention, it can be suitably used in a belt-type continuously variable transmission that employs clutch fuse control.

FIG. 2 is a skeleton diagram showing the configuration of a drive system of a vehicle. FIG. 2 is a circuit diagram showing the configuration of a hydraulic circuit according to an embodiment of the present invention, and also shows the flow of hydraulic pressure when the input torque is in a high torque state and the shift range is in the R range. FIG. 3 is a circuit diagram showing the configuration of a hydraulic circuit, and also shows the flow of hydraulic pressure when the input torque is in a high torque state and the shift range is in the D range. It is a circuit diagram showing a configuration of a hydraulic circuit, and also shows the flow of oil pressure when the input torque is in a low torque state and the shift range is in the R range. FIG. 2 is a circuit diagram showing the configuration of a hydraulic circuit, and also shows the flow of hydraulic pressure when the input torque is in a low torque state and the shift range is in the D range. It is a figure showing the relationship between line pressure (PL pressure) and clutch modulator pressure. FIG. 3 is a diagram showing a list of gear change ranges, driving conditions, linear solenoid valve conditions, on/off valve conditions, and output pressure conditions of an engagement clutch and a shift valve. It is a circuit diagram showing the composition of the hydraulic circuit concerning a modification.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

<Vehicle drive system>
FIG. 1 is a skeleton diagram showing the configuration of a drive system of a vehicle 1. As shown in FIG.

The vehicle 1 is equipped with an engine 2 as a drive source, and employs, for example, an FR (Front-engine Rear-wheel-drive) layout. The engine 2 is, for example, a 3-cylinder, 4-stroke engine, and is mounted vertically at the front of the vehicle 1 with the crankshaft 3 oriented vertically with respect to the longitudinal direction of the vehicle 1 (hereinafter simply referred to as the "longitudinal direction"). It will be installed. The power of the engine 2 is input to the transmission unit 4. The power output from the transmission unit 4 is transmitted to the differential gear 6 via the propeller shaft 5, and from the differential gear 6 to the left and right drive wheels (rear wheels) 7L, 7R.

Note that the engine 2 is not limited to a three-cylinder four-stroke engine. The number of cylinders in the engine 2 is not limited to three, but may be four or more, or two or less. Further, the number of strokes of the engine 2 is not limited to four strokes, but may be two strokes.

The transmission unit 4 includes a torque converter 8 and a CVT 9 inside a unit case that forms an outer shell.

The torque converter 8 is a torque converter with a lockup mechanism, and includes a front cover 11, a pump impeller 12, a turbine runner 13, and a lockup clutch (lockup piston) 14.

The front cover 11 extends in a substantially disk shape around a rotational axis extending in the front-rear direction, and has an outer peripheral end bent toward the rear side, which is the side opposite to the engine 2 side. The crankshaft 3 of the engine 2 is coupled to the center of the front cover 11 so as to be relatively non-rotatable.

The pump impeller 12 is arranged on the rear side of the front cover 11. An outer peripheral end of the pump impeller 12 is connected to an outer peripheral end of the front cover 11, and the pump impeller 12 is provided to be rotatable integrally with the front cover 11.

Turbine runner 13 is arranged between front cover 11 and pump impeller 12.

Lockup clutch 14 is located between front cover 11 and turbine runner 13. When the oil pressure in the engagement side oil chamber 15 on the turbine runner 13 side with respect to the lockup clutch 14 is higher than the oil pressure in the release side oil chamber 16 on the front cover 11 side, the lockup clutch 14 moves to the front cover due to the differential pressure. 11 side, the lock-up clutch 14 is pressed against the front cover 11, and the pump impeller 12 and the turbine runner 13 are directly connected (lock-up on).

Conversely, if the oil pressure in the release side oil chamber 16 is higher than the oil pressure in the engagement side oil chamber 15, the differential pressure causes the lockup clutch 14 to move toward the turbine runner 13. When the lock-up clutch 14 is separated from the front cover 11, the direct connection between the pump impeller 12 and the turbine runner 13 is released (lock-up off). When the pump impeller 12 rotates due to engine torque in the lock-up off state, oil flows from the pump impeller 12 toward the turbine runner 13. This oil flow is received by the turbine runner 13, and the turbine runner 13 rotates. At this time, the amplification effect of the torque converter 8 occurs, and a torque larger than the engine torque is generated in the turbine runner 13.

The CVT 9 includes an input shaft 21, a continuously variable transmission mechanism 22, a reverse transmission mechanism 23, and an output shaft 24. The CVT 9 is provided so that the input shaft 21 is oriented vertically and extends in the front-rear direction.

Input shaft 21 extends on the rotational axis of torque converter 8 and is provided to be rotatable integrally with turbine runner 13 of torque converter 8 . An input shaft gear 25 is integrally formed with the input shaft 21 or is supported so as to be non-rotatable.

The continuously variable transmission mechanism 22 includes a primary shaft 31, a secondary shaft 32, a primary pulley 33, a secondary pulley 34, and a belt 35.

The primary shaft 31 extends parallel to the input shaft 21 with its axial center spaced apart to the lower right when viewed from the rear side with respect to the axial center of the input shaft 21 . The secondary shaft 32 extends parallel to the input shaft 21 with its axial center spaced apart to the upper left when viewed from the rear side with respect to the axial center of the input shaft 21 . In this way, the primary shaft 31 and the secondary shaft 32 are arranged on the left and right sides of the input shaft 21. Thereby, the distance between the primary shaft 31 and the secondary shaft 32 in the vertical direction can be shortened, and the size of the CVT 9 in the vertical direction can be reduced. Therefore, even if the vehicle 1 is a vehicle with a low-floor cabin such as a commercial vehicle, the transmission unit 4 can be mounted on the vehicle 1 while ensuring the minimum ground clearance of the vehicle 1. .

The primary pulley 33 is arranged to face a primary fixed sheave 41 fixed to the primary shaft 31 with a belt 35 interposed between the primary fixed sheave 41 and is supported by the primary shaft 31 so as to be movable in its axial direction but not relatively rotatable. A primary movable sheave 42 is provided. The primary movable sheave 42 is arranged on the front side with respect to the primary fixed sheave 41.

A cylinder 43 is provided on the side opposite to the primary fixed sheave 41 side with respect to the primary movable sheave 42, that is, on the front side. The cylinder 43 has an inner peripheral end fixed to the primary shaft 31, extends from the primary shaft 31 in the shaft radial direction, and an outer peripheral end bent rearward. The outer peripheral end of the primary movable sheave 42 is in liquid-tight contact with the outer peripheral end of the cylinder 43 from inside in the rotational radial direction. A hydraulic chamber (piston chamber) 44 is formed between the primary movable sheave 42 and the cylinder 43.

The secondary pulley 34 is arranged to face a secondary fixed sheave 45 fixed to the secondary shaft 32 with the belt 35 interposed between the secondary fixed sheave 45 and is supported by the secondary shaft 32 so as to be movable in its axial direction but not relatively rotatable. A secondary movable sheave 46 is provided. The secondary movable sheave 46 is disposed on the rear side with respect to the secondary fixed sheave 45, and the positional relationship between the secondary fixed sheave 45 and the secondary movable sheave 46 in the front-rear direction is such that the primary fixed sheave 41 of the primary pulley 33 and the primary The positional relationship with the movable sheave 42 is reversed.

A piston 47 is provided on the side opposite to the secondary fixed sheave 45 with respect to the secondary movable sheave 46, that is, on the rear side. The piston 47 has an inner peripheral end fixed to the secondary shaft 32 and extends from the secondary shaft 32 in the shaft radial direction. The outer circumferential end of the secondary movable sheave 46 extends rearward, and the outer circumferential end of the piston 47 fluid-tightly contacts the outer circumferential end of the secondary movable sheave 46 from inside in the rotational radial direction. A hydraulic chamber 48 is formed between the secondary movable sheave 46 and the piston 47.

In the continuously variable transmission mechanism 22, the hydraulic pressure supplied to the hydraulic chambers 44, 48 of the primary pulley 33 and the secondary pulley 34 is controlled, and the groove widths of the primary pulley 33 and the secondary pulley 34 are changed. The gear ratio (the pulley ratio between the primary pulley 33 and the secondary pulley 34) is continuously and steplessly changed within a fixed gear ratio range.

Specifically, when the belt transmission ratio is decreased, the hydraulic pressure supplied to the hydraulic chamber 44 of the primary pulley 33 is increased. As a result, the primary movable sheave 42 of the primary pulley 33 moves toward the primary fixed sheave 41, and the interval (groove width) between the primary fixed sheave 41 and the primary movable sheave 42 becomes smaller. Accordingly, the winding diameter of the belt 35 around the primary pulley 33 increases, and the interval (groove width) between the secondary fixed sheave 45 and the secondary movable sheave 46 of the secondary pulley 34 increases. As a result, the belt transmission ratio becomes smaller.

When the belt speed ratio is increased, the hydraulic pressure supplied to the hydraulic chamber 44 of the primary pulley 33 is lowered. As a result, the thrust force of the secondary pulley 34 with respect to the belt 35 becomes larger than the thrust force of the primary pulley 33 with respect to the belt 35, the distance between the secondary fixed sheave 45 and the secondary movable sheave 46 of the secondary pulley 34 becomes smaller, and the primary fixed sheave 41 and the primary movable sheave 42 becomes larger. As a result, the belt transmission ratio increases.

Although not shown, a bias spring is provided in the hydraulic chamber 48 of the secondary pulley 34. The bias spring has one end in elastic contact with the secondary movable sheave 46 and the other end in elastic contact with the piston 47. The elastic force of the bias spring biases the secondary movable sheave 46 and the piston 47 in a direction away from each other. A biasing force is applied to the secondary movable sheave 46 by the hydraulic pressure in the hydraulic chamber 48 and a bias spring, and a corresponding pinching pressure is applied to the belt 35.

A primary input gear 51 is supported at the front end of the primary shaft 31 so as to be relatively rotatable.

A forward clutch 52 is provided between the primary input gear 51 and the primary pulley 33 disposed on the rear side. The forward clutch 52 is a hydraulic friction clutch that is engaged by hydraulic pressure and prohibits rotation of the primary input gear 51 with respect to the primary shaft 31. Therefore, when the forward clutch 52 is engaged, when the primary input gear 51 rotates, the primary shaft 31 rotates together with the primary input gear 51. When the hydraulic pressure is released from the engaged forward clutch 52, the forward clutch 52 is released. By releasing the forward clutch 52, rotation of the primary input gear 51 with respect to the primary shaft 31 is allowed, and even if the primary input gear 51 rotates, the rotation is not transmitted to the primary shaft 31.

A secondary input gear 53 is supported at the front end of the secondary shaft 32 so as to be relatively rotatable.

A reverse clutch 54 is provided between the secondary input gear 53 and the secondary pulley 34 disposed on the rear side. The reverse clutch 54 is a hydraulic friction clutch that is engaged by hydraulic pressure and prohibits rotation of the secondary input gear 53 with respect to the secondary shaft 32. Therefore, when the secondary input gear 53 rotates, the secondary shaft 32 rotates together with the secondary input gear 53. When the hydraulic pressure is released from the engaged reverse clutch 54, the reverse clutch 54 is released. By releasing the reverse clutch 54, rotation of the secondary input gear 53 with respect to the secondary shaft 32 is allowed, and even if the secondary input gear 53 rotates, the rotation is not transmitted to the secondary shaft 32.

The reverse transmission mechanism 23 is a mechanism that transmits the power (rotation) of the input shaft 21 to the secondary shaft 32 without passing through the continuously variable transmission mechanism 22. Reverse transmission mechanism 23 includes a reverse idler shaft 55, a first reverse gear 56, and a second reverse gear 57.

The reverse idler shaft 55 extends in the front-rear direction parallel to the input shaft 21.

The first reverse gear 56 is formed integrally with the reverse idler shaft 55, or is formed separately from the reverse idler shaft 55, and is supported by the reverse idler shaft 55 so as not to be relatively rotatable.

The output shaft 24 is disposed on the same axis as the input shaft 21 with a space behind the input shaft 21 . An output shaft gear 58 is formed integrally with the output shaft 24 or is formed separately from the output shaft 24 and is supported so as to be relatively non-rotatable. Correspondingly, a secondary output gear 59 is supported by spline fitting on the secondary shaft 32 adjacent to the rear side of the piston 47 of the secondary pulley 34 so as to be relatively non-rotatable. The output shaft gear 58 and the secondary output gear 59 are in mesh with each other.

When the vehicle 1 is traveling forward, the forward clutch 52 is engaged and the reverse clutch 54 is released. Power input from the engine 2 to the input shaft 21 via the torque converter 8 is transmitted from the input shaft gear 25 to the primary shaft 31 via the primary input gear 51 by engagement of the forward clutch 52 . On the other hand, even if the power input to the input shaft 21 is transmitted from the input shaft gear 25 to the secondary input gear 53 and the secondary input gear 53 rotates, the release of the reverse clutch 54 causes the secondary input gear 53 to rotate to the secondary shaft 32. The secondary shaft 32 rotates idly, and no power is transmitted to the secondary shaft 32.

The power transmitted to the primary shaft 31 is transmitted to the secondary shaft 32 after being changed in speed at a belt speed ratio according to the pulley ratio between the primary pulley 33 and the secondary pulley 34 . The power transmitted to the secondary shaft 32 is transmitted from the secondary output gear 59 to the output shaft 24 via the output shaft gear 58, and from the output shaft 24 to the propeller shaft 5.

When the vehicle 1 is traveling backwards, the forward clutch 52 is released and the reverse clutch 54 is engaged. Power input from the engine 2 to the input shaft 21 via the torque converter 8 is transmitted from the input shaft gear 25 to the secondary shaft 32 via the reverse transmission mechanism 23 and the secondary input gear 53 by engagement of the reverse clutch 54. Ru. At this time, the secondary shaft 32 rotates in the opposite direction to when the vehicle 1 moves forward. On the other hand, even if the power input to the input shaft 21 is transmitted from the input shaft gear 25 to the primary input gear 51 and the primary input gear 51 rotates, the release of the forward clutch 52 causes the primary input gear 51 to move toward the primary shaft 31. The primary shaft 31 idles and no power is transmitted to the primary shaft 31.

The power transmitted to the secondary shaft 32 is transmitted from the secondary output gear 59 to the output shaft 24 via the output shaft gear 58, and from the output shaft 24 to the propeller shaft 5.

<Hydraulic circuit>
2A, 2B, 2C, and 2D are circuit diagrams showing the configuration of a hydraulic circuit 101 according to an embodiment of the present invention.

The hydraulic circuit 101 is a circuit for supplying hydraulic pressure to the forward clutch 52 and the reverse clutch 54, and is incorporated into the hydraulic circuit of the transmission unit 4 as a part thereof.

Hydraulic circuit 101 includes a clutch modulator valve 102, a linear solenoid valve 103, a shift valve 104, an on/off valve 105, and a manual valve 106.

The clutch modulator valve 102 is a valve that regulates line pressure (PL pressure), which is a source pressure obtained by regulating the hydraulic pressure generated by an oil pump (not shown), to a predetermined clutch modulator pressure (Pc pressure) and outputs the pressure. be. Clutch modulator valve 102 includes a substantially cylindrical sleeve 111. A spool 112 and a spring 113 are provided within the sleeve 111.

The sleeve 111 has a first inner diameter section 114, a second inner diameter section 115, and a third inner diameter section 116 that have different inner diameters. The first inner diameter portion 114, the second inner diameter portion 115, and the third inner diameter portion 116 are formed in this order from one side of the sleeve 111 in the centerline direction. The inner diameter of the first inner diameter section 114 is smaller than the inner diameter of the second inner diameter section 115 and the inner diameter of the third inner diameter section 116, and the inner diameter of the second inner diameter section 115 is smaller than the inner diameter of the third inner diameter section 116.

The spool 112 is provided so as to be movable in the direction of the centerline of the sleeve 111, and is elastically pressed toward one side in the direction of the centerline by a spring 113.

On the spool 112, a first land portion 117, a second land portion 118, and a third land portion 119 are provided in this order from one side in the centerline direction at intervals from each other. The first land portion 117 is formed into a substantially cylindrical shape having an outer diameter corresponding to the inner diameter of the first inner diameter portion 114 of the sleeve 111 . The second land portion 118 is formed into a substantially cylindrical shape having an outer diameter corresponding to the inner diameter of the second inner diameter portion 115 of the sleeve 111 . The third land portion 119 is formed into a substantially cylindrical shape having an outer diameter corresponding to the inner diameter of the third inner diameter portion 116 of the sleeve 111 . In the movable range of the spool 112, regardless of the position of the spool 112, the first land portion 117, the second land portion 118, and the third land portion 119 are at least partially connected to the first inner diameter portion 114 of the sleeve 111, respectively. It faces the second inner diameter part 115 and the third inner diameter part 116 with almost no gap.

An input port 121, an output port 122, a first feedback port 123, a second feedback port 124, and a third feedback port 125 are formed in the sleeve 111.

Due to the design of each part of the clutch modulator valve 102, the input port 121 is provided in the third inner diameter portion 116, and the area closed by the third land portion 119 of the spool 112 changes as the spool 112 moves. Further, the output port 122 is provided in the third inner diameter portion 116 and is not closed by the third land portion 119 regardless of the position of the spool 112 (so that the opening area does not change). The first feedback port 123 is provided in the first inner diameter portion 114 and communicates between the first land portion 117 and one end surface of the sleeve 111 in the centerline direction, regardless of the position of the spool 112. The second feedback port 124 is provided at a position spanning the first inner diameter part 114 and the second inner diameter part 115, and is located between the first land part 117 and the second land part 118 regardless of the position of the spool 112. communicate with. The third feedback port 125 is provided at a position spanning the second inner diameter part 115 and the third inner diameter part 116, and is located between the second land part 18 and the third land part 119 regardless of the position of the spool 112. communicate with.

The linear solenoid valve 103 is a normally closed type linear solenoid valve that is fully closed when not energized. The clutch modulator pressure output from the clutch modulator valve 102 is input to the input port 131 of the linear solenoid valve 103 . By controlling the energization of the linear solenoid valve 103 (electromagnetic coil), the clutch modulator pressure input to the input port 131 is regulated to a linear solenoid pressure, and the linear solenoid pressure is output from the output port 132. .

The shift valve 104 is a valve that selectively outputs the clutch modulator pressure output from the clutch modulator valve 102 and the linear solenoid pressure output from the linear solenoid valve 103. The shift valve 104 includes a substantially cylindrical sleeve 141. A spool 142 and a spring 143 are provided within the sleeve 141.

The spool 142 is provided so as to be movable between a control position and a fail position in the direction of the centerline of the sleeve 141, and is elastically pressed by a spring 143 toward one side in the direction of the centerline, that is, toward the control position. On the spool 142, a first land portion 144, a second land portion 145, and a third land portion 146 are provided in this order from one side in the centerline direction at intervals from each other. The first land portion 144 , the second land portion 145 , and the third land portion 146 are formed into a substantially cylindrical shape having the same outer diameter according to the inner diameter of the sleeve 141 .

A first input port 151, a second input port 152, a third input port 153, a fourth input port 154, a first output port 155, and a second output port 156 are formed in the sleeve 141.

Due to the design of each part of the shift valve 104, the first input port 151 communicates between one end surface of the sleeve 141 in the centerline direction and the first land portion 144, regardless of the position of the spool 142. The second input port 152 communicates with the first land portion 144 and the second land portion 145 when the spool 142 is located at the control position, and communicates with the first land portion 145 when the spool 142 is located at the fail position. It is closed by section 144. The third input port 153 communicates with the second land portion 145 and the third land portion 146 when the spool 142 is located in the control position, and communicates with the first land portion 146 when the spool 142 is located in the fail position. The portion 144 communicates with the second land portion 145. The fourth input port 154 communicates between the third land portion 146 and the other end surface of the sleeve 141 in the centerline direction, regardless of the position of the spool 142. The first output port 155 communicates between the first land portion 144 and the second land portion 145 regardless of the position of the spool 142. The second output port 156 communicates between the second land portion 145 and the third land portion 146 regardless of the position of the spool 142.

The on/off valve 105 is a normally closed type on/off solenoid valve, and is turned on (output state) when energized, and turned off (output stopped state) when not energized. The clutch modulator pressure output from the clutch modulator valve 102 is input to the input port 161 of the on/off valve 105 . When the on/off valve 105 is in the on state, clutch modulator pressure is output from the output port 162, and the clutch modulator pressure is input to the fourth input port 154 of the shift valve 104.

The manual valve 106 includes a spool 171 that is displaced in response to manual operation of a shift lever disposed in the vehicle interior, and converts hydraulic pressure input into an input port 172 into a forward output port 173 or a backward force corresponding to the position of the shift lever. This is a valve that outputs from port 174.

Specifically, the CVT 9 has a shift range including, for example, a P (parking) range, an R (reverse) range, an N (neutral) range, and a D (drive) range. A shift lever (select lever) is provided in the cabin of the vehicle 1 in order to instruct switching of the transmission range. The movable range of the shift lever includes a P position, an R position, an N position, and a D position, corresponding to the shift range.

The hydraulic pressure (clutch modulator pressure or linear solenoid pressure) output from the first output port 155 of the shift valve 104 is input to the input port 172 of the manual valve 106 . When the shift lever is in the D position, the hydraulic pressure input to the input port 172 is output from the forward output port 173. Furthermore, when the shift lever is in the R position, the hydraulic pressure input to the input port 172 is output from the rearward output port 174.

One end of a forward clutch oil passage 175 is connected to the forward output port 173. The other end of the forward clutch oil passage 175 is connected to the forward clutch 52. Thereby, the hydraulic pressure output from the forward output port 173 is supplied to the forward clutch 52 through the forward clutch oil passage 175. Further, one end of a branch oil passage 176 is branched and connected to the middle of the forward clutch oil passage 175. The other end of the branch oil passage 176 is connected to the second feedback port 124 of the clutch modulator valve 102. Therefore, the hydraulic pressure output from the forward output port 173 is also input to the second feedback port 124 of the clutch modulator valve 102 from the forward clutch oil passage 175 through the branch oil passage 176.

One end of a reverse clutch oil passage 177 is connected to the reverse output port 174 . The other end of the reverse clutch oil passage 177 is connected to the reverse clutch 54. As a result, the hydraulic pressure output from the reverse output port 174 is supplied to the reverse clutch 54 through the reverse clutch oil passage 177.

<Circuit operation>
FIG. 3 is a diagram showing the relationship between line pressure (PL pressure) and clutch modulator pressures P1, P2, P3, and P4. FIG. 4 is a diagram showing a list of gear ranges, driving conditions, states of the linear solenoid valve 103, states of the on/off valve 105, and states of the output pressures of the engagement clutch and the shift valve 104.

In each of FIGS. 2A to 2D and FIG. 4, the forward clutch 52 is labeled "C1" and the reverse clutch 54 is labeled "C2."

The vehicle 1 is equipped with a plurality of ECUs including a microcomputer to control each part. The plurality of ECUs are connected to enable bidirectional communication using a CAN (Controller Area Network) communication protocol. One of the plurality of ECUs controls the operation of the hydraulic circuit 101 according to the shift range and the driving state.

In the vehicle 1, when the input torque input to the input shaft 21 of the CVT 9 is in a low torque state below a predetermined value, clutch fuse control is executed by the ECU. If the input torque is in a high torque state equal to or higher than a predetermined value, clutch fuse control is not executed. Clutch fuse control is a control that causes the forward clutch 52 or reverse clutch 54 to slip before the belt 35 of the continuously variable transmission mechanism 22 when excessive torque is input from the road surface to the drive wheels 7L, 7R. . Specifically, in clutch fuse control, the hydraulic pressure (engagement pressure), that is, the linear solenoid pressure output by the linear solenoid valve 103 is regulated.

When the input torque is in a high torque state, the power supply to the linear solenoid valve 103 and the on/off valve 105 is cut off, and the output of the linear solenoid pressure from the linear solenoid valve 103 and the clutch modulator pressure from the on/off valve 105 is stopped. be done.

At this time, as shown by the thick gray line in FIGS. 2A and 2B, the clutch modulator pressure output from the output port 122 of the clutch modulator valve 102 is input to the first input port 151 and the third input port 153 of the shift valve 104. be done. The clutch modulator pressure input to the first input port 151 causes the spool 142 of the shift valve 104 to resist the elastic force of the spring 143 and to be in the fail position (high torque, fail). In this state, the third input port 153 communicates with the first output port 155 via the first land portion 144 and the second land portion 145 of the spool 142. Therefore, the clutch modulator pressure input to the first input port 151 is output from the first output port 155 and input to the input port 172 of the manual valve 106 .

When the shift range is in the R range, the shift lever is in the R position, so the clutch modulator pressure input to the input port 172 of the manual valve 106 is applied to the rearward output port 174 to shift the reverse gear as shown in FIG. 2A. It is output to clutch oil path 177. As a result, the clutch modulator pressure is supplied to the reverse clutch 54 through the reverse clutch oil passage 177, and the reverse clutch 54 is engaged with the clutch modulator pressure.

Furthermore, the clutch modulator pressure output from the output port 122 of the clutch modulator valve 102 is input to the first feedback port 123 of the clutch modulator valve 102. Therefore, the first land portion 117 of the spool 112 of the clutch modulator valve 102 receives pressure due to the product of the clutch modulator pressure and the pressure receiving area that receives this clutch modulator pressure, and the spool 117 is positioned at a position where the pressure balances the elastic force of the spring 113. moves. As a result, the area closed by the third land portion 119 at the input port 121 of the clutch modulator valve 102 increases, the line pressure is reduced to a constant clutch modulator pressure P1, and the clutch modulator pressure P1 is output from the output port 122. Ru.

When the shift range is the D range, the shift lever is in the D position, so the clutch modulator pressure input to the input port 172 of the manual valve 106 is transferred to the forward output port 173 from the forward output port 173, as shown in FIG. 2B. It is output to clutch oil path 175. As a result, the clutch modulator pressure is supplied to the forward clutch 52 through the forward clutch oil passage 175, and the forward clutch 52 is engaged with the clutch modulator pressure.

Furthermore, the clutch modulator pressure output from the output port 122 of the clutch modulator valve 102 is input to the first feedback port 123 of the clutch modulator valve 102. Therefore, the first land portion 117 of the spool 112 of the clutch modulator valve 102 receives pressure based on the product of the clutch modulator pressure and the pressure receiving area that receives this clutch modulator pressure. Further, the clutch modulator pressure output to the forward clutch oil passage 175 is input to the third feedback port 125 of the clutch modulator valve 102 through the branch oil passage 176. Therefore, in the clutch modulator valve 102, the second land portion 118 and the third land portion 119 of the spool 112 newly receive the clutch modulator pressure input to the third feedback port 125, and the spool 112 has the second land portion 118 and the third land portion 119 A pressure equal to the difference in pressure receiving area between the third land portion 119 and the third land portion 119 multiplied by the clutch modulator pressure acts. As a result, the area closed by the third land portion 119 at the input port 121 of the clutch modulator valve 102 increases, the line pressure is reduced to a constant clutch modulator pressure P2 lower than the clutch modulator pressure P1, and the line pressure is reduced to a constant clutch modulator pressure P2 that is lower than the clutch modulator pressure P1. is output from the output port 122.

Note that if a power loss failure occurs in the hydraulic circuit 101, the power to the linear solenoid valve 103 and the on/off valve 105 is cut off, so the operation of the hydraulic circuit 101 is similar to that when the input torque is in a high torque state. The operation will be similar.

When the input torque is in a low torque state, energization of the linear solenoid valve 103 is controlled. By controlling this energization, a variably regulated linear solenoid pressure is output from the output port 132 of the linear solenoid valve 103. The linear solenoid pressure output from the output port 132 is input to the second input port 152 of the shift valve 104. Further, the on/off valve 105 is energized and turned on. As a result, the clutch modulator pressure is output from the output port 162 of the on/off valve 105, and the output clutch modulator pressure is input to the fourth input port 154 of the shift valve 104.

At this time, as shown by thick gray lines in FIGS. 2C and 2D, the clutch modulator pressure output from the output port 122 of the clutch modulator valve 102 is input to the first input port 151 and the third input port 153 of the shift valve 104. be done. As a result, the clutch modulator pressure input to the first input port 151 and the clutch modulator pressure input to the fourth input port 154 cancel each other out, and the spool 142 of the shift valve 104 is controlled by the elastic force of the spring 143. position (low torque, engagement transient).

Further, the second input port 152 communicates with the first output port 155 via the first land portion 144 and the second land portion 145 of the spool 142 . Therefore, the linear solenoid pressure input to the second input port 152 is output from the first output port 155 and input to the input port 172 of the manual valve 106, as shown by the gray center line in FIGS. 2C and 2D. be done.

When the shift range is the R range, the clutch modulator pressure input to the input port 172 of the manual valve 106 is output from the reverse output port 174 to the reverse clutch oil passage 177, as shown in FIG. 2C. As a result, linear solenoid pressure is supplied to the reverse clutch 54 through the reverse clutch oil passage 177. By controlling the energization to the linear solenoid valve 103 and increasing or decreasing the linear solenoid pressure, it is possible to switch between engagement and disengagement of the reverse clutch 54, and also to maintain the reverse clutch 54 in the engaged state. can.

Furthermore, the clutch modulator pressure output from the output port 122 of the clutch modulator valve 102 is input to the first feedback port 123 of the clutch modulator valve 102. Therefore, the first land portion 117 of the spool 112 of the clutch modulator valve 102 receives pressure based on the product of the clutch modulator pressure and the pressure receiving area that receives this clutch modulator pressure. Further, in the shift valve 104, the third input port 153 and the second output port 156 communicate with each other via the second land portion 145 and the third land portion 146 of the spool 142. Therefore, the clutch modulator pressure input to the third input port 153 is output from the second output port 156. Clutch modulator pressure output from second output port 156 is input to second feedback port 124 of clutch modulator valve 102 . Therefore, in the clutch modulator valve 102, the first land portion 117 and the second land portion 118 of the spool 112 receive the clutch modulator pressure input to the second feedback port 124, and the spool 112 has the first land portion 117 and the second land portion 118. A pressure equal to the difference in pressure receiving area with the second land portion 118 multiplied by the clutch modulator pressure is further applied. As a result, the line pressure is reduced to a constant clutch modulator pressure P3 that is lower than the clutch modulator pressure P1, and the clutch modulator pressure P3 is output from the output port 122.

When the shift range is the D range, the clutch modulator pressure input to the input port 172 of the manual valve 106 is output from the forward output port 173 to the forward clutch oil passage 175, as shown in FIG. 2D. As a result, clutch modulator pressure is supplied to the forward clutch 52 through the forward clutch oil passage 175. By controlling the energization of the linear solenoid valve 103 to increase or decrease the linear solenoid pressure, the forward clutch 52 can be switched between engagement and disengagement, and the forward clutch 52 can be maintained in the engaged state. can.

Further, similarly to when the shift range is the R range, the first land portion 117 of the spool 112 of the clutch modulator valve 102 receives pressure from the clutch modulator pressure input to the first feedback port 123, and the first land portion 117 and second land portion 118 receives clutch modulator pressure input to second feedback port 124. Furthermore, the linear solenoid pressure output to the forward clutch oil passage 175 is input to the third feedback port 125 of the clutch modulator valve 102 through the branch oil passage 176. Therefore, in the clutch modulator valve 102, the second land portion 118 and the third land portion 119 of the spool 112 receive the linear solenoid pressure input to the third feedback port 125. A pressure equal to the difference in pressure receiving area with the third land portion 119 multiplied by the linear solenoid pressure acts. As a result, the line pressure is reduced to a constant clutch modulator pressure P4 that is lower than the clutch modulator pressure P3, and the clutch modulator pressure P4 is output from the output port 122.

<Effect>
As described above, the line pressure is input to the clutch modulator valve 102, and the clutch modulator valve 102 regulates the line pressure to the clutch modulator pressure and outputs it. The clutch modulator pressure output from the clutch modulator valve 102 is input to the linear solenoid valve 103, and the linear solenoid valve 103 regulates the clutch modulator pressure to a linear solenoid pressure and outputs it. The clutch modulator pressure output from the clutch modulator valve 102 is input to the on/off valve 105 .

When the on/off valve 105 is in the on state, clutch modulator pressure is output from the on/off valve 105, the clutch modulator pressure is input to the shift valve 104, and the spool 142 of the shift valve 104 is located at the control position. In this state, the linear solenoid pressure output from the linear solenoid valve 103 is input to the second input port 152 of the shift valve 104, and the linear solenoid pressure is output from the shift valve 104 to the forward clutch 52 or reverse clutch 54. supplied to

The linear solenoid pressure can be increased or decreased by controlling the energization of the linear solenoid valve 103. The transmission torque capacity of the forward clutch 52 or the reverse clutch 54 can be increased or decreased by increasing or decreasing the linear solenoid pressure. Therefore, the hydraulic circuit 101 can be suitably used in the transmission unit 4 mounted on the vehicle 1 that employs clutch fuse control.

On the other hand, when the on/off valve 105 is in the off state, the output of the clutch modulator pressure from the on/off valve 105 is stopped, so no clutch modulator pressure is input from the on/off valve 105 to the shift valve 104. Therefore, the spool 142 is located at the fail position. In this state, the clutch modulator pressure output from the clutch modulator valve 102 is input to the clutch modulator pressure input port, and the clutch modulator pressure is supplied to the forward clutch 52 or the reverse clutch 54.

When a power loss failure occurs, the on/off valve 105 is turned off, so clutch modulator pressure is supplied from the shift valve 104 to the forward clutch 52 or the reverse clutch 54. As a result, the forward clutch 52 or the reverse clutch 54 is engaged. Therefore, when a power loss failure occurs, the forward clutch 52 or the reverse clutch 54 is engaged, so that the transmission unit 4 can output power for driving the vehicle 1, and the driving of the vehicle 1 is ensured. can do.

The clutch modulator valve 102 has a second feedback port 124 into which the linear solenoid pressure supplied to the forward clutch 52 or the reverse clutch 54 is input. Clutch modulator pressure decreases in response to linear solenoid pressure.

As a result, the clutch modulator pressure input to the linear solenoid valve 103 is reduced, so the differential pressure between the clutch modulator pressure and the linear solenoid pressure output from the linear solenoid valve 103 can be reduced, and the override characteristic of the linear solenoid valve 103 is reduced. can be improved.

<Modified example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

For example, in the hydraulic circuit 101 according to the embodiment described above, the normally closed type on/off valve 105 is used, and when the on/off valve 105 is in the on state, the clutch modulator pressure is output from the output port 162 of the on/off valve 105. It is assumed that the clutch modulator pressure is input to the fourth input port 154 of the shift valve 104. The configuration of the hydraulic circuit 101 is not limited to this, and the configuration of the hydraulic circuit 201 shown in FIG. 5 may be adopted.

In the hydraulic circuit 101, a normally closed type on/off valve 105 is used, whereas in the hydraulic circuit 101, a normally open type on/off valve 202 is used in place of the normally closed type on/off valve 105. It is being The normally open type on/off valve 202 is turned off (output stopped state) when energized, and turned on (output state) when not energized. The clutch modulator pressure output from the clutch modulator valve 102 is input to the input port 203 of the on/off valve 202 . When the on/off valve 202 is in the on state, clutch modulator pressure is output from the output port 204, and the clutch modulator pressure is input to the first input port 151 of the shift valve 104.

When the input torque is in a high torque state or in a fail state, power to the on/off valve 105 is cut off. At this time, the clutch modulator pressure is output from the output port 204 of the on/off valve 105, and the clutch modulator pressure is input to the first input port 151 of the shift valve 104. The clutch modulator pressure input to the first input port 151 causes the spool 142 of the shift valve 104 to resist the elastic force of the spring 143 and to be in the fail position (high torque, fail).

When the input torque is in a low torque state, the on/off valve 105 is energized and turned on. As a result, the output of clutch modulator pressure from the output port 162 of the on/off valve 105 is stopped, so the spool 142 of the shift valve 104 is placed in the control position (low torque, engagement transient) by the elastic force of the spring 143. do.

Therefore, the configuration of the hydraulic circuit 201 can also provide the same effects as the configuration of the hydraulic circuit 101. Moreover, in the configuration of the hydraulic circuit 201, the fourth input port 154 of the shift valve 104 is used as a drain port, and there is no need to input hydraulic pressure, so the configuration is simpler than that of the hydraulic circuit 101.

Further, in the above-described embodiment, the CVT 9 is placed vertically, but the hydraulic circuit 101 may also be applied to a transmission unit including a transmission placed horizontally so that the input shaft extends in the left-right direction of the vehicle 1. can.

In addition, various design changes can be made to the above-described configuration within the scope of the claims.

4: Transmission unit (transmission)
9: CVT (transmission)
52: Forward clutch (engaging element)
54: Reverse clutch (engaging element)
101: Hydraulic circuit 102: Clutch modulator valve (modulator valve)
103: Linear solenoid valve (solenoid valve)
104: Shift valve 105: On/off valve 124: Second feedback port (feedback port)
142: Spool 151: First input port (modulator pressure input port)
152: Second input port (engagement pressure input port)
153: Third input port (modulator pressure input port)

Claims (1)

A hydraulic circuit for a transmission comprising an engagement element,
a modulator valve to which a source pressure is input, and which adjusts the input source pressure to a predetermined modulator pressure and outputs it;
a linear solenoid valve that receives the modulator pressure from the modulator valve, regulates the input modulator pressure to a linear solenoid pressure, and outputs the modulator pressure;
The modulator pressure is input from the modulator valve, the input modulator pressure is output in the on state, and the output of the modulator pressure is stopped in the off state, and the engagement transient and engagement retention of the engagement element are controlled. an on/off valve that is turned on for the purpose of
A first input port and a third input port to which the modulator pressure is input from the modulator valve, a second input port to which the linear solenoid pressure is input from the linear solenoid valve, and a second input port to which the modulator pressure is input from the on/off valve. The linear solenoid pressure is input to the second input port, and the linear solenoid pressure is input to the second input port. The modulator pressure input to the third input port is outputted as the hydraulic pressure supplied to the engagement element, and the modulator pressure input to the third input port is outputted as the hydraulic pressure supplied to the engagement element when the spool is located at the fail position. including a shift valve;
The shift valve is configured to transfer the modulator pressure input to the fourth input port and the modulator pressure from the modulator valve to the first input port when the modulator pressure is input from the on/off valve to the fourth input port. When the input modulator pressures cancel each other out, the spool is in the control position, and there is no input of the modulator pressure from the on/off valve to the fourth input port, the spool is in the fail position. Located in
The modulator valve includes a first feedback port into which the modulator pressure outputted by the modulator valve is input, and a second feedback port into which the hydraulic pressure supplied to the engagement element is input, and the modulator valve By inputting the modulator pressure to be outputted to the first feedback port, the source pressure is reduced to the first modulator pressure, and the modulator pressure outputted by the modulator valve is inputted to the first feedback port. and has a configuration in which the source pressure is reduced to a second modulator pressure lower than the first modulator pressure by inputting the hydraulic pressure supplied to the engagement element to the second feedback port. The hydraulic circuit.

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