JP6377581B2 - Hydraulic circuit - Google Patents

Description

  The present invention relates to a hydraulic circuit for a continuously variable transmission.

  A CVT (Continuously Variable Transmission) is widely known as a transmission mounted on a vehicle.

  The CVT has a configuration in which an endless belt is wound around an input-side primary pulley and an output-side secondary pulley. When torque from a drive source such as an engine is input to the primary pulley, the torque is transmitted from the primary pulley to the belt due to the frictional force between the primary pulley and the belt, and due to the frictional force between the secondary pulley and the belt. Torque is transmitted from the belt to the secondary pulley.

  The primary pulley and the secondary pulley are both arranged so as to face the fixed sheave, with the belt sandwiched between the fixed sheave and the movable sheave movably provided in the facing direction. And a piston that forms a piston chamber (oil chamber) with the movable sheave.

  In CVT, the interval between the fixed sheave and the movable sheave of the primary pulley is changed by taking in and out the oil supplied to the piston chamber of the primary pulley. Accordingly, the belt winding diameter with respect to the primary pulley changes, the interval between the fixed sheave and the movable sheave of the secondary pulley changes, and the belt winding diameter with respect to the secondary pulley changes. As a result, the gear ratio (pulley ratio) changes continuously in a stepless manner. Further, the belt is clamped between the fixed sheave and the movable sheave of each pulley with a thrust according to the hydraulic pressure (hydraulic pressure acting on the movable sheave) supplied to the piston chamber of each pulley. The thrust of each pulley needs to be large enough to prevent slippage between each pulley and the belt, and the hydraulic pressure acting on the movable sheave of each pulley is adjusted so that the necessary thrust is obtained.

JP 2004-176890 A

  FIG. 5 is a circuit diagram showing a configuration of a hydraulic circuit 203 for supplying oil to the primary pulley 201 and the secondary pulley 202.

  The hydraulic circuit 203 includes a primary solenoid valve 204 and a primary pressure regulating valve 205 for controlling the hydraulic pressure (primary sheave pressure) acting on the movable sheave of the primary pulley 201, and the hydraulic pressure (secondary pressure) acting on the movable sheave of the secondary pulley 202. A secondary solenoid valve 206 and a secondary pressure regulating valve 207 for controlling the sheave pressure) are included.

  The primary solenoid valve 204 is a valve that can control the output hydraulic pressure by an electrical signal. A predetermined clutch modulator pressure Pc is input to the primary solenoid valve 204, and a hydraulic pressure corresponding to an electrical signal is output from the primary solenoid valve 204.

  A constant line pressure is input to the input port 211 of the primary pressure regulating valve 205, and the output hydraulic pressure of the primary solenoid valve 204 is input to the signal port 212. In the primary pressure regulating valve 205, the line pressure inputted to the input port 211 is regulated according to the hydraulic pressure inputted to the signal port 212, and the primary sheave pressure Pin generated by the pressure regulation is outputted from the output port 213. The The output port 213 of the primary pressure regulating valve 205 communicates with the piston chamber of the primary pulley 201, and the primary sheave pressure Pin output from the output port 213 is supplied to the piston chamber, and the primary sheave pressure Pin is supplied to the primary pulley 201. Acts on the movable sheave.

  The secondary solenoid valve 206 is a valve that can control the output hydraulic pressure by an electrical signal. A predetermined clutch modulator pressure Pc is input to the secondary solenoid valve 206, and a hydraulic pressure corresponding to the electrical signal is output from the secondary solenoid valve 206.

  A constant line pressure is input to the input port 221 of the secondary pressure regulating valve 207, and the output hydraulic pressure of the secondary solenoid valve 206 is input to the signal port 222. In the secondary pressure regulating valve 207, the line pressure inputted to the input port 221 is regulated according to the hydraulic pressure inputted to the signal port 222, and the secondary sheave pressure Pd generated by the pressure regulation is outputted from the output port 223. The The output port 223 of the secondary pressure regulating valve 207 communicates with the piston chamber of the secondary pulley 202, the secondary sheave pressure Pd output from the output port 223 is supplied to the piston chamber, and the secondary sheave pressure Pd is the secondary pulley 202. Acts on the movable sheave.

  Each of the primary solenoid valve 204 and the secondary solenoid valve 206 is a normally open type (normally open type) linear solenoid valve that is fully opened when power is not supplied. Therefore, when the primary solenoid valve 204 and the secondary solenoid valve 206 are not energized due to harness disconnection or the like, the primary sheave pressure Pin and the secondary sheave pressure Pd become the maximum oil pressure, that is, the output oil pressure equal to the line pressure. Generally, the pressure receiving area of the movable sheave of the primary pulley 201 (area receiving the primary sheave pressure Pin) is larger than the pressure receiving area of the movable sheave of the secondary pulley 202 (area receiving the secondary sheave pressure Pd). The thrust of the pulley 201 becomes larger than the thrust of the secondary pulley 202, and the CVT constitutes a high ratio in which the gear ratio is smaller than 1.

  As a result, if a failure occurs when the belt winding diameter of the primary pulley 201 is small, thrust due to the maximum hydraulic pressure is applied from the primary pulley 201 to the belt, so that the tensile stress acting on the belt becomes excessive and the life of the belt is reduced. To do. Further, when the vehicle stops in a fail state, the CVT has a high ratio, so that it is difficult to restart the vehicle.

  As a countermeasure, it is conceivable to reduce the primary sheave pressure Pin and the secondary sheave pressure Pd by reducing the line pressure so that the gear ratio of CVT becomes about 1 at the time of failure.

  However, if both the primary sheave pressure Pin and the secondary sheave pressure Pd are reduced, the belt may slip due to insufficient thrust when the output torque of the engine is high. By limiting the engine output torque at the time of failure, slipping of the belt can be suppressed. However, if the engine output torque is limited, the vehicle running conditions are restricted, such as being unable to climb up, and fail safe. Guarantee of driving becomes difficult.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic circuit for a continuously variable transmission that can suppress the occurrence of belt slippage due to insufficient thrust without limiting the torque input to the primary pulley while being able to configure a gear ratio of about 1 at the time of failure. Is to provide.

  In order to achieve the above object, a hydraulic circuit according to the present invention is used in a continuously variable transmission having a configuration in which an endless belt is wound around a primary pulley and a secondary pulley. A hydraulic circuit for supplying a sheave pressure and a secondary sheave pressure, having a first input port, a solenoid signal port, a fail signal port, and a first output port. The solenoid signal port and the fail signal port The hydraulic pressure input to the first input port is adjusted to the primary sheave pressure by the input signal pressure, and the primary sheave pressure is output from the first output port and input to the solenoid signal port. Normally open type primary solenoid valve that outputs signal pressure A second input port, a signal port, and a second output port, and by adjusting the hydraulic pressure input to the second input port to the secondary sheave pressure by the signal pressure input to the signal port, the secondary sheave pressure is A secondary pressure regulating valve that outputs from the second output port; a normally open type secondary solenoid valve that outputs the signal pressure input to the signal port; a third input port and a third output port; a primary solenoid valve; A fail-safe valve that outputs the hydraulic pressure output from the second output port to the third input port and outputs the signal pressure input to the fail signal port from the third output port when the secondary solenoid valve cannot be energized. Including.

  According to this configuration, at the normal time (normal time) when the primary solenoid valve and the secondary solenoid valve can be energized, the signal pressure output from the primary solenoid valve is input to the solenoid signal port of the primary pressure regulating valve. Further, the signal pressure output from the secondary solenoid valve is input to the signal port of the secondary pressure regulating valve. In the secondary pressure regulating valve, the hydraulic pressure input to the second input port is regulated to the secondary sheave pressure by the signal pressure, and the secondary sheave pressure is output from the second output port. Normally, the secondary sheave pressure output from the second output port is not input to the third input port of the fail-safe valve. Therefore, no signal pressure is output from the third output port of the fail-safe valve, and no signal pressure is input to the fail signal port of the primary pressure regulating valve. Therefore, in the primary pressure regulating valve, the hydraulic pressure input to the first input port is regulated to the primary sheave pressure by the signal pressure input to the solenoid signal port, and the primary sheave pressure is output from the first output port. The

  On the other hand, both the primary solenoid valve and the secondary solenoid valve are fully opened when the primary solenoid valve and the secondary solenoid valve fail during energization. When the secondary solenoid valve is fully opened, the signal pressure input from the secondary solenoid valve to the signal port of the secondary pressure regulating valve is maximized, and the secondary sheave pressure output from the second output port of the secondary pressure regulating valve is the maximum hydraulic pressure. Become. The secondary sheave pressure output from the second output port of the secondary pressure regulating valve is input to the third input port of the fail safe valve, and the signal pressure is output from the third output port of the fail safe valve. This signal pressure is input to the fail signal port of the primary pressure regulating valve. On the other hand, since the primary solenoid valve is fully opened, the signal pressure is also input from the primary solenoid valve to the solenoid signal port of the primary pressure regulating valve. Therefore, in the primary pressure regulating valve, the hydraulic pressure input to the first input port is regulated to the primary sheave pressure by the signal pressure input to the fail signal port and the solenoid signal port, respectively, and the primary sheave pressure is Output from one output port.

  Therefore, between the minimum value and the maximum value of the hydraulic pressure input to the third input port of the fail-safe valve, that is, the secondary sheave pressure output from the second output port of the secondary pressure regulating valve, By designing each part so that the gear ratio obtained by the primary sheave pressure and the secondary sheave pressure respectively supplied is about 1, without suppressing the hydraulic pressure input to the second input port of the secondary pressure regulating valve. A gear ratio of about 1 can be configured at the time of failure.

  As a result, it is possible to suppress an excessive tensile stress from acting on the belt when a failure occurs, and to extend the life of the belt. Even if a vehicle equipped with a continuously variable transmission stops in a fail state, the speed ratio is about 1, so that the vehicle can be restarted. Furthermore, sufficient hydraulic pressure can be supplied to the primary pulley and the secondary pulley, and the thrust of the primary pulley and the secondary pulley can be maintained in the same way as normal, so that the torque input to the primary pulley, for example, the engine output torque is limited. Even if it is not provided, the occurrence of belt slip due to insufficient thrust can be suppressed.

  Line pressure corresponding to the oil pressure generated by the oil pump may be input to the first input port of the primary pressure regulating valve and the second input port of the secondary pressure regulating valve.

  In this case, a vehicle on which the continuously variable transmission is mounted may be an engine as a power source, and the oil pump may be a mechanical oil pump that is driven by the power of the engine.

  As a result, the hydraulic pressure generated by the oil pump becomes a hydraulic pressure corresponding to the engine output torque, and the line pressure input to the first input port of the primary pressure regulating valve and the second input port of the secondary pressure regulating valve becomes the engine output torque. Since the hydraulic pressure corresponds, thrust according to the output torque of the engine can be applied to the belt from the primary pulley and the secondary pulley. Therefore, the occurrence of belt slip due to insufficient thrust can be suppressed regardless of the magnitude of the engine output torque.

  According to the present invention, while it is possible to configure a gear ratio of about 1 at the time of a failure, it is possible to suppress the occurrence of belt slip due to insufficient thrust without limiting the torque input to the primary pulley.

It is a skeleton figure which shows the structure of the drive system of the vehicle carrying a continuously variable transmission. It is a circuit diagram showing the composition of the hydraulic circuit concerning one embodiment of the present invention. It is a figure which shows the characteristic of the line pressure in normal time, a clutch modulator pressure, a primary sheave pressure, and a secondary sheave pressure. It is a figure which shows the characteristic of the primary sheave pressure at the time of fail safe. It is a circuit diagram which shows the conventional structure of the hydraulic circuit of a continuously variable transmission.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Configuration of drive system>

  FIG. 1 is a skeleton diagram showing a configuration of a drive system of a vehicle 1 on which a continuously variable transmission 4 is mounted.

  The vehicle 1 is an automobile that uses an engine (E / G) 2 as a power source. The output of the engine 2 is transmitted to drive wheels (for example, left and right front wheels) of the vehicle 1 via a torque converter 3 and a continuously variable transmission (CVT) 4.

  The engine 2 includes an E / G output shaft 21. The E / G output shaft 21 is rotated by the power generated by the engine 2.

  The torque converter 3 includes a pump impeller 31, a turbine runner 32, and a lockup clutch 33. An E / G output shaft 21 is connected to the pump impeller 31, and the pump impeller 31 is provided so as to be integrally rotatable about the same rotation axis as the E / G output shaft 21. The turbine runner 32 is provided to be rotatable about the same rotation axis as the pump impeller 31. The lockup clutch 33 is provided to directly connect / separate the pump impeller 31 and the turbine runner 32. When the lockup clutch 33 is engaged, the pump impeller 31 and the turbine runner 32 are directly connected, and when the lockup clutch 33 is released, the pump impeller 31 and the turbine runner 32 are separated.

  When the E / G output shaft 21 is rotated in a state where the lockup clutch 33 is released, the pump impeller 31 rotates. When the pump impeller 31 rotates, an oil flow from the pump impeller 31 toward the turbine runner 32 is generated. This oil flow is received by the turbine runner 32 and the turbine runner 32 rotates. At this time, the amplifying action of the torque converter 3 occurs, and the turbine runner 32 generates a power larger than the power (torque) of the E / G output shaft 21.

  In a state where the lockup clutch 33 is engaged, when the E / G output shaft 21 is rotated, the E / G output shaft 21, the pump impeller 31, and the turbine runner 32 are rotated together.

  An oil pump 5 is provided between the torque converter 3 and the continuously variable transmission 4. The oil pump 5 is a mechanical oil pump, and the pump shaft is disposed so that the rotational axis of the pump impeller 31 coincides with the pump impeller 31 and is coupled to the pump impeller 31 so as not to be relatively rotatable. Thereby, when the pump impeller 31 is rotated by the power of the engine 2, the pump shaft of the oil pump 5 is rotated and oil is discharged from the oil pump 5.

  The continuously variable transmission 4 transmits the power input from the torque converter 3 to the differential gear 6. The continuously variable transmission 4 includes an input shaft 41, an output shaft 42, a belt transmission mechanism 43, and a forward / reverse switching mechanism 44.

  The input shaft 41 is connected to the turbine runner 32 of the torque converter 3 and is provided so as to be integrally rotatable about the same rotation axis as the turbine runner 32.

  The output shaft 42 is arranged in parallel with the input shaft 41. An output gear 45 is supported on the output shaft 42 so as not to be relatively rotatable.

  The belt transmission mechanism 43 includes a primary shaft 51 and a secondary shaft 52. The primary shaft 51 and the secondary shaft 52 are on the same axis as the input shaft 41 and the output shaft 42, respectively, and are disposed so as to at least partially overlap in a direction perpendicular to the axial direction.

  The belt transmission mechanism 43 has a configuration in which an endless belt 55 is wound around a primary pulley 53 supported by a primary shaft 51 and a secondary pulley 54 supported by a secondary shaft 52.

  The primary pulley 53 is disposed so as to face the fixed sheave 61 fixed to the primary shaft 51 with the belt 55 sandwiched between the fixed sheave 61 and is supported by the primary shaft 51 so as to be movable in the axial direction but not to be relatively rotatable. 62. A piston 63 fixed to the primary shaft 51 is provided on the opposite side of the movable sheave 62 from the fixed sheave 61, and a piston chamber (oil chamber) 64 is formed between the movable sheave 62 and the piston 63. Yes.

  The secondary pulley 54 is disposed to face the fixed sheave 65 fixed to the secondary shaft 52 with the belt 55 sandwiched between the fixed sheave 65 and is supported by the secondary shaft 52 so as to be movable in the axial direction but not to be relatively rotatable. A movable sheave 66 is provided. A piston 67 fixed to the secondary shaft 52 is provided on the opposite side of the movable sheave 66 from the fixed sheave 65, and a piston chamber (oil chamber) 68 is formed between the movable sheave 66 and the piston 67. Yes.

  In the continuously variable transmission 4, the hydraulic pressure supplied to the piston chamber 64 of the primary pulley 53 and the piston chamber 68 of the secondary pulley 54 is controlled, and the groove widths of the primary pulley 53 and the secondary pulley 54 are changed. The gear ratio is continuously changed steplessly.

  Specifically, when the gear ratio is lowered, the hydraulic pressure (primary sheave pressure Pin) supplied to the piston chamber 64 of the primary pulley 53 is increased. As a result, the movable sheave 62 of the primary pulley 53 moves to the fixed sheave 61 side, and the interval (groove width) between the fixed sheave 61 and the movable sheave 62 is reduced. Accordingly, the winding diameter of the belt 55 around the primary pulley 53 is increased, and the interval (groove width) between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 is increased. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 is reduced, and the gear ratio is reduced.

  When the gear ratio is increased, the primary sheave pressure Pin supplied to the piston chamber 64 of the primary pulley 53 is decreased. Thereby, the thrust of the secondary pulley 54 with respect to the belt 55 becomes larger than the thrust of the primary pulley 53 with respect to the belt 55, the interval between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 is reduced, and the fixed sheave 61 and the movable sheave The distance from 62 increases. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 is increased, and the gear ratio is increased.

  On the other hand, the thrust of the primary pulley 53 and the secondary pulley 54 needs to be large enough to prevent slippage between the primary pulley 53 and the secondary pulley 54 and the belt 55. Therefore, the primary sheave pressure Pin supplied to the piston chamber 64 of the primary pulley 53 and the hydraulic pressure supplied to the piston chamber 68 of the secondary pulley 54 so that a thrust according to the magnitude of the torque input to the input shaft 41 can be obtained. (Secondary sheave pressure Pd) is controlled.

  The forward / reverse switching mechanism 44 is interposed between the input shaft 41 and the primary shaft 51 of the belt transmission mechanism 43. The forward / reverse switching mechanism 44 includes a planetary gear mechanism 71, a reverse clutch C1, and a forward brake B1.

  The planetary gear mechanism 71 includes a carrier 72, a sun gear 73, and a ring gear 74.

  The carrier 72 is fitted on the input shaft 41 so as to be relatively rotatable. The carrier 72 rotatably supports a plurality of pinion gears 75. The plurality of pinion gears 75 are arranged on the circumference.

  The sun gear 73 is supported by the input shaft 41 so as not to be relatively rotatable, and is disposed in a space surrounded by the plurality of pinion gears 75. The gear teeth of the sun gear 73 mesh with the gear teeth of each pinion gear 75.

  The ring gear 74 is provided such that its rotational axis coincides with the axis of the primary shaft 51. A primary shaft 51 of the belt transmission mechanism 43 is connected to the ring gear 74. The gear teeth of the ring gear 74 are formed so as to collectively surround the plurality of pinion gears 75 and mesh with the gear teeth of each pinion gear 75.

  The reverse clutch C1 is switched between an engaged state (on) in which the carrier 72 and the sun gear 73 are directly coupled (coupled so as to be integrally rotatable) and a released state (off) in which the direct coupling is released.

  The forward brake B <b> 1 is provided between the carrier 72 and a transmission case that houses the torque converter 3 and the continuously variable transmission 4. The forward brake B <b> 1 is engaged (on) for braking the carrier 72 and released to allow the carrier 72 to rotate. Switch to state (off).

  When the vehicle 1 moves forward, the reverse clutch C1 is released and the forward brake B1 is engaged. When the power of the engine 2 is input to the input shaft 41, the sun gear 73 rotates integrally with the input shaft 41 while the carrier 72 is stationary. Therefore, the rotation of the sun gear 73 is transmitted to the ring gear 74 while being reversed and decelerated. As a result, the ring gear 74 rotates, and the primary shaft 51 and the primary pulley 53 of the belt transmission mechanism 43 rotate together with the ring gear 74. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate the secondary pulley 54 and the secondary shaft 52. Then, the output shaft 42 and the output gear 45 rotate integrally with the secondary shaft 52. The output gear 45 meshes with the differential gear 6 (the input gear of the differential gear 6). When the output gear 45 rotates, the drive shafts 7 and 8 extending left and right from the differential gear 6 rotate and drive wheels (not shown) rotate, so that the vehicle 1 moves forward.

  On the other hand, when the vehicle 1 moves backward, the reverse clutch C1 is engaged and the forward brake B1 is released. When the power of the engine 2 is input to the input shaft 41, the carrier 72 and the sun gear 73 rotate integrally with the input shaft 41. Therefore, the rotation of the sun gear 73 is transmitted to the ring gear 74 without reversing the rotation direction. As a result, the ring gear 74 rotates in the direction opposite to that when the vehicle 1 moves forward, and the primary shaft 51 and the primary pulley 53 of the belt transmission mechanism 43 rotate together with the ring gear 74. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate the secondary pulley 54 and the secondary shaft 52. Then, the output shaft 42 and the output gear 45 rotate integrally with the secondary shaft 52. When the output gear 45 rotates, the drive shafts 7 and 8 extending from the differential gear 6 to the left and right rotate in the opposite direction to the forward movement, and the drive wheels (not shown) rotate, whereby the vehicle 1 moves backward.

<Hydraulic circuit>

  FIG. 2 is a circuit diagram showing a main part of the hydraulic circuit 101 of the continuously variable transmission 4.

  The hydraulic circuit 101 of the continuously variable transmission 4 includes various valves for supplying the primary sheave pressure Pin and the secondary sheave pressure Pd to the primary pulley 53 and the secondary pulley 54, respectively. That is, the hydraulic circuit 101 includes a primary solenoid valve 102 (SLP), a primary pressure regulating valve 103, a secondary solenoid valve 104 (SLS), a secondary pressure regulating valve 105, and a fail safe valve 106.

  The primary solenoid valve 102 is a normally open type (normally open type) linear solenoid valve that is fully opened when power is not supplied. Clutch modulator pressure Pc is input to primary solenoid valve 102. By controlling energization to the primary solenoid valve 102, the primary solenoid valve 102 regulates the clutch modulator pressure Pc to the solenoid pressure Pslp and outputs it.

  The clutch modulator pressure Pc is a constant hydraulic pressure regulated by a clutch modulator valve (not shown), and is used as a source pressure of supply pressure to the reverse clutch C1 and the forward brake B1 (see FIG. 1).

  The primary pressure regulating valve 103 is a pressure control valve for controlling the primary sheave pressure Pin. The primary pressure regulating valve 103 includes a sleeve 111 having a substantially cylindrical peripheral wall. In the sleeve 111, a first spool 112 and a second spool 113 are arranged in the center line direction so as to be movable in the center line direction. Land portions 114, 115, 116, and 117 are formed on the first spool 112 at intervals in the center line direction. Land portions 118 and 119 are formed in the second spool 113 at intervals in the center line direction. The land portions 116 and 117 of the first spool 112 and the land portion 118 of the second spool 113 have the same diameter. The diameter of the land portion 114 of the first spool 112 is smaller than the diameter of the land portion 115, and the diameter of the land portion 115 is smaller than the diameter of the land portion 116. The diameter of the land portion 119 of the second spool 113 is smaller than the diameter of the land portions 116 to 118. In the sleeve 111, a spring 120 for biasing the second spool 113 toward the first spool 112 (upper side) is provided at an end portion on the second spool 113 side (lower side).

  An input port 121, signal ports 122, 123, 124, 125, an output port 126, and drain ports 127, 128, 129 are formed on the peripheral wall of the sleeve 111.

  The input port 121 communicates with the land portions 116 and 117 in a state where the first spool 112 is positioned at the top, and is closed by the land portion 116 in a state where the first spool 112 is positioned at the bottom. A line pressure PL is input to the input port 121.

  The signal port 122 communicates between the land portion 119 and the lower end of the sleeve 111 regardless of the position of the second spool 113. A solenoid pressure Pslp that is an output hydraulic pressure of the primary solenoid valve 102 is input to the signal port 122.

  The signal port 123 communicates with the land portions 115 and 116 regardless of the position of the first spool 112. The primary sheave pressure Pin output from the output port 126 is fed back to the signal port 123.

  The signal port 124 communicates with the land portions 118 and 119 regardless of the position of the second spool 113.

  The signal port 125 communicates between the land portion 114 and the upper end of the sleeve 111 regardless of the position of the first spool 112.

  The output port 126 communicates with the land portions 116 and 117 regardless of the position of the first spool 112. Further, the output port 126 communicates with the piston chamber 64 (see FIG. 1) of the primary pulley 53.

  The drain port 127 is closed by the land portion 117 with the first spool 112 positioned at the uppermost position, and communicates between the land portions 116 and 117 with the first spool 112 positioned at the lowermost position.

  The drain port 128 communicates with the land portions 114 and 115 regardless of the position of the first spool 112.

  The drain port 129 communicates with the land portions 117 and 118 regardless of the positions of the first spool 112 and the second spool 113.

  The secondary solenoid valve 104 is a normally open type (normally open type) linear solenoid valve that is fully opened when power is not supplied. Clutch modulator pressure Pc is input to secondary solenoid valve 104. By controlling the energization of the secondary solenoid valve 104, the secondary solenoid valve 104 adjusts the clutch modulator pressure Pc to the solenoid pressure Psls and outputs it.

  The line pressure PL is a hydraulic pressure generated by regulating the hydraulic pressure generated by the oil pump 5 (see FIG. 1) by a regulator valve (not shown). Specifically, the solenoid pressure Psls output from the secondary solenoid valve 104 is input to the signal port of the regulator valve. The regulator valve regulates the line pressure PL to a hydraulic pressure proportional to the solenoid pressure Psls (see FIG. 3).

  The secondary pressure regulating valve 105 is a pressure control valve for controlling the secondary sheave pressure Pd. The secondary pressure regulating valve 105 includes a sleeve 131 having a substantially cylindrical peripheral wall. A spool 132 is provided in the sleeve 131 so as to be movable in the center line direction. Land portions 133, 134, and 135 are formed in the spool 132 at intervals in the center line direction. The land portions 134 and 135 have the same diameter, and the land portion 133 has a smaller diameter than the land portions 134 and 135. In the sleeve 131, a spring 136 for biasing the spool 132 toward the other end (upper side) is provided at one end (lower side) in the center line direction.

  An input port 141, signal ports 142 and 143, an output port 144, and drain ports 145 and 146 are formed on the peripheral wall of the sleeve 131.

  The input port 141 communicates with the land portions 134 and 135 when the spool 132 is positioned at the uppermost position, and is closed by the land portion 135 when the spool 132 is positioned at the lowest position. The line pressure PL is input to the input port 141.

  The signal port 142 communicates between the land portion 135 and the lower end of the sleeve 131 regardless of the position of the spool 132. A solenoid pressure Psls that is an output hydraulic pressure of the secondary solenoid valve 104 is input to the signal port 142.

  The signal port 143 communicates with the land portions 133 and 134 regardless of the position of the spool 132. The signal port 143 is fed back with the secondary sheave pressure Pd output from the output port 144.

  The output port 144 communicates with the land portions 134 and 135 regardless of the position of the spool 132. The output port 144 communicates with the piston chamber 68 (see FIG. 1) of the secondary pulley 54.

  The drain port 145 is closed by the land portion 135 with the spool 132 positioned at the uppermost position, and communicates between the land portions 134 and 135 with the spool 132 positioned at the lowermost position.

  The drain port 146 communicates between the land portion 133 and the upper end of the sleeve 131 regardless of the position of the spool 132.

  The fail safe valve 106 is a valve for inputting the secondary sheave pressure Pd as a signal pressure to the signal port 124 of the primary pressure regulating valve 103 when the primary solenoid valve 102 and the secondary solenoid valve 104 cannot be energized. The failsafe valve 106 includes a sleeve 151 having a substantially cylindrical peripheral wall. A spool 152 is provided in the sleeve 151 so as to be movable in the center line direction. In the spool 152, land portions 153, 154, 155, and 156 are formed at intervals in the center line direction. The land portions 154, 155, and 156 have the same diameter, and the land portion 153 has a smaller diameter than the land portions 154, 155, and 156. In the sleeve 151, a spring 157 for biasing the spool 152 toward the other end (upper side) is provided at the end on one end side (lower side) in the center line direction.

  Input ports 161 and 162, signal ports 163, output ports 164 and 165, and drain ports 166, 167, and 168 are formed on the peripheral wall of the sleeve 151.

  The input port 161 is closed by the land portion 156 with the spool 152 positioned at the uppermost position, and communicates with the land portions 155 and 156 with the spool 152 positioned at the lowermost position. Further, the input port 161 communicates with the output port 144 of the secondary pressure regulating valve 105.

  The input port 162 is closed by the land portion 155 in a state where the spool 152 is positioned at the uppermost position, and communicates between the land portions 154 and 155 in a state where the spool 152 is positioned at the lowermost position. The clutch modulator pressure Pc is input to the input port 162.

  The signal port 163 communicates between the land portion 153 and the upper end of the sleeve 151 regardless of the position of the spool 152. A solenoid pressure Pslp that is an output hydraulic pressure of the primary solenoid valve 102 is input to the signal port 163.

  The output port 164 communicates with the land portions 155 and 156 regardless of the position of the spool 152. The output port 164 communicates with the signal port 124 of the primary pressure regulating valve 103.

  The output port 165 communicates with the land portions 154 and 155 regardless of the position of the spool 152. The output port 165 communicates with the signal port 125 of the primary pressure regulating valve 103.

  The drain port 166 communicates with the land portions 154 and 155 with the spool 152 positioned at the uppermost position, and communicates with the land portions 153 and 154 with the spool 152 positioned at the lowermost position.

  The drain port 167 communicates with the land portions 153 and 154 regardless of the position of the spool 152.

  The drain port 168 communicates with the land portions 155 and 156 in a state where the spool 152 is positioned at the uppermost position, and is closed by the land portion 155 in a state where the spool 152 is positioned at the lowermost position.

<Normal (normal)>

  FIG. 3 is a diagram illustrating characteristics of the line pressure PL, the clutch modulator pressure Pc, the primary sheave pressure Pin, and the secondary sheave pressure Pd in a normal state.

  At normal times, energization to the primary solenoid valve 102 and the secondary solenoid valve 104 is controlled based on the target values of the primary sheave pressure Pin and the secondary sheave pressure Pd. As a result, the solenoid pressure Pslp corresponding to the target value of the primary sheave pressure Pin is output from the primary solenoid valve 102, and the solenoid pressure Psls corresponding to the target value of the secondary sheave pressure Pd is output from the secondary solenoid valve 104.

  The solenoid pressure Pslp output from the primary solenoid valve 102 at normal time is equal to or lower than a predetermined normal maximum pressure, and the primary solenoid valve 102 has a surplus area where the solenoid pressure Pslp exceeding the normal maximum pressure can be output. The solenoid pressure Pslp is input to the signal port 122 of the primary pressure regulating valve 103. As the solenoid pressure Pslp input to the signal port 122 increases, the opening area of the input port 121 increases and the primary sheave pressure Pin output from the output port 126 of the primary pressure regulating valve 103 increases. For example, as shown in FIG. 3, the primary sheave pressure Pin increases substantially in proportion to the solenoid pressure Pslp input to the signal port 122.

  The solenoid pressure Psls output from the secondary solenoid valve 104 is input to the signal port 142 of the secondary pressure regulating valve 105. As the solenoid pressure Psls input to the signal port 142 increases, the opening area of the input port 141 increases, and the secondary sheave pressure Pd output from the output port 144 of the secondary pressure regulating valve 105 increases. For example, as shown in FIG. 3, the secondary sheave pressure Pd increases substantially in proportion to the magnitude of the solenoid pressure Psls input to the signal port 142.

<When fail safe>

  FIG. 4 is a diagram showing characteristics of the primary sheave pressure Pin at the time of fail safe.

  When the primary solenoid valve 102 and the secondary solenoid valve 104 fail to be energized, the primary solenoid valve 102 and the secondary solenoid valve 104 are normally open type (normally open) linear solenoid valves. Solenoid pressures Pslp and Psls of maximum pressure are output from the solenoid valve 104, respectively.

  When the maximum solenoid pressure Psls is input to the signal port 142 of the secondary pressure regulating valve 105, the secondary sheave corresponding to the line pressure PL input to the input port 141 is output from the output port 144 of the secondary pressure regulating valve 105. The pressure Pd is output.

  Further, the solenoid pressure Pslp output from the primary solenoid valve 102 exceeds the normal maximum pressure. When the solenoid pressure Pslp in the surplus region exceeding the normal maximum pressure is input to the signal port 163 of the failsafe valve 106, the spool 152 of the failsafe valve 106 moves to the lowest position (failure position). Thereby, fail safe is started. When the spool 152 moves to the lowest position, the input port 161 communicates with the land portions 155 and 156, the secondary sheave pressure Pd is input to the input port 162, and the hydraulic pressure corresponding to the secondary sheave pressure Pd is output from the output port 164. Is output. Further, the input port 162 communicates with the land portions 154 and 155, the clutch modulator pressure Pc is input to the input port 162, and the hydraulic pressure corresponding to the clutch modulator pressure Pc is output from the output port 165.

  The hydraulic pressure (signal pressure) output from the output ports 164 and 165 of the fail safe valve 106 is input to the signal ports 124 and 125 of the primary pressure regulating valve 103, respectively. On the other hand, the solenoid pressure Pslp output from the primary solenoid valve 102 is input to the signal port 122 of the primary pressure regulating valve 103. As a result, the first spool 112 and the second spool 113 of the primary pressure regulating valve 103 move to positions corresponding to the hydraulic pressures input to the signal ports 122, 124 and 125, respectively, and the output port 126 of the primary pressure regulating valve 103. From, the primary sheave pressure Pin corresponding to the position of the first spool 112 is output.

  In the hydraulic circuit 101, for example, the hydraulic pressure input to the signal port 125 of the primary pressure regulating valve 103 substantially matches the solenoid pressure Pslp input to the signal port 122, and the solenoid pressure Pslp input to the signal port 122 is the second pressure. Each part is designed so that the axial load applied to the spool 113 and the axial load applied to the first spool 112 by the hydraulic pressure input to the signal port 125 are offset. Therefore, the first spool 112 and the second spool 113 of the primary pressure regulating valve 103 are moved by the hydraulic pressure input from the output port 164 of the fail safe valve 106 to the signal port 124, that is, the hydraulic pressure corresponding to the secondary sheave pressure Pd. As a result, the primary sheave pressure Pin output from the output port 126 of the primary pressure regulating valve 103 is regulated by the hydraulic pressure corresponding to the secondary sheave pressure Pd, and changes approximately in proportion to the secondary sheave pressure Pd.

<Effect>

  As described above, at the time of fail safe, the secondary sheave pressure Pd corresponding to the line pressure PL input to the input port 141 is output from the output port 144 of the secondary pressure regulating valve 105. In addition, a hydraulic pressure corresponding to the secondary sheave pressure Pd is input to the signal port 124 of the primary pressure regulating valve 103. In the primary pressure regulating valve 103, the input port is determined by the hydraulic pressure (signal pressure) input to the signal port 124. The hydraulic pressure input to 121 is adjusted to the primary sheave pressure Pin, and the primary sheave pressure Pin is output from the output port 126.

  Therefore, the primary sheave pressure Pin and the secondary sheave supplied to the primary pulley 53 and the secondary pulley 54 between the minimum value of the secondary sheave pressure Pd (secondary sheave pressure Pd that can be generated during idling rotation of the engine 2) and the maximum value, respectively. By designing each part so that the gear ratio obtained by the sheave pressure Pd is about 1, the line pressure PL inputted to the input port 141 of the secondary pressure regulating valve 105 is not suppressed, and about 1 at the time of fail-safe. Can be configured.

  As a result, it is possible to prevent an excessive tensile stress from acting on the belt 55 when a failure occurs, and to extend the life of the belt 55. Even if the vehicle 1 on which the continuously variable transmission 4 is mounted stops in a failed state, the vehicle 1 can be restarted because the gear ratio is about 1. Furthermore, since sufficient hydraulic pressure can be supplied to the primary pulley 53 and the secondary pulley 54, and the thrust of the primary pulley 53 and the secondary pulley 54 can be maintained in the same manner as normal time, torque input to the primary pulley 53, for example, the engine 2 Even if there is no restriction on the output torque, the occurrence of slippage of the belt 55 due to insufficient thrust can be suppressed.

  The oil pump 5 provided in the continuously variable transmission 4 is a mechanical oil pump that is driven by the power of the engine 2. The hydraulic pressure generated by the oil pump 5 becomes a hydraulic pressure corresponding to the output torque of the engine 2, and in the hydraulic circuit 101, the line pressure PL input to the input port 121 of the primary pressure regulating valve 103 and the input port 141 of the secondary pressure regulating valve 105 is Since the hydraulic pressure corresponds to the output torque of the engine 2, a thrust corresponding to the output torque of the engine 2 can be applied to the belt 55 from the primary pulley 53 and the secondary pulley 54. Therefore, regardless of the magnitude of the output torque of the engine 2, the occurrence of slipping of the belt 55 due to insufficient thrust can be suppressed.

<Modification>

  As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form.

  For example, in the hydraulic circuit 101, in order to cancel or reduce the axial load applied to the second spool 113 by the solenoid pressure Pslp input to the signal port 122 of the primary pressure regulating valve 103, the signal port 125 of the primary pressure regulating valve 103. The hydraulic pressure corresponding to the clutch modulator pressure Pc is input to However, the present invention is not limited to this configuration, and a hydraulic pressure unrelated to the clutch modulator pressure Pc may be input to the signal port 125 of the primary pressure regulating valve 103.

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

4 continuously variable transmission 53 primary pulley 54 secondary pulley 101 hydraulic circuit 102 primary solenoid valve 103 primary pressure regulating valve 104 secondary solenoid valve 105 secondary pressure regulating valve 106 fail safe valve 121 input port (first input port)
122 Signal port (Signal port for solenoid)
124 Signal port (Fail signal port)
126 output port (first output port)
141 Input port (second input port)
142 signal port 144 output port (second output port)
161 Input port (third input port)
164 Output port (third output port)

Claims (1)

A hydraulic circuit for supplying a primary sheave pressure and a secondary sheave pressure to the primary pulley and the secondary pulley, respectively, for use in a continuously variable transmission having an endless belt wound around a primary pulley and a secondary pulley. There,
The first input port, the signal port solenoid has a first signal port for fail, a second signal port and the first output port for fail, the signal pressure input to the signal port for the solenoid, the first input A primary pressure regulating valve that regulates the hydraulic pressure input to the port to a primary sheave pressure and outputs the primary sheave pressure from the first output port;
A normally open type primary solenoid valve that outputs a signal pressure input to the solenoid signal port;
A second input port, a signal port, and a second output port, the hydraulic pressure input to the second input port is adjusted to a secondary sheave pressure by the signal pressure input to the signal port, and the secondary sheave pressure is A secondary pressure regulating valve that outputs from the second output port;
A normally open type secondary solenoid valve that outputs a signal pressure input to the signal port;
The third input port has a third input port , a third output port, and a fourth output port , and the hydraulic pressure output from the second output port when the primary solenoid valve and the secondary solenoid valve cannot be energized fails. The signal pressure input to the first signal port for fail is output from the third output port, and the signal pressure input to the second signal port for fail is output from the fourth output port . only contains a fail-safe valve,
At the time of the failure, in the primary pressure regulating valve, an axial load applied to the spool of the primary pressure regulating valve by a signal pressure input to the solenoid signal port, and a signal pressure input to the second signal port for failure. A hydraulic circuit in which an axial load applied to the spool is canceled and a hydraulic pressure corresponding to a signal pressure input to the first signal port for fail is output from the first output port .

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