JPH05126250A - Electromagnetic control device of servo unit for transmission - Google Patents

Abstract

PURPOSE:To obtain a control device simple in its structure while actuating a fail-safe when a solenoid is in improper action. CONSTITUTION:Oil of fixed pressure is supplied to a rod side cylinder chamber 52 from an oil path 102, and oil of governing its pressure by the first/second solenoid valves 151, 152, duty ratio-controlled to open/close, is supplied to a head side cylinder chamber 53 through oil paths 103, 104. When both the solenoid valves 151, 152 are turned off (open) together, a low pressure of oil is generated in the head side cylinder chamber 53 by action of two orifices 61, 62. Consequently, by a difference between pressing force of acting on a piston 54a by the low pressure of oil and pressing force of acting on the piston by a predetermined pressure of oil in the rod side cylinder chamber 52, the piston is slowly moved to any one of the stroke ends. By movement to this stroke end, speed change ratio is changed low so as to change a clutch placed in a fully released condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic control device for controlling a hydraulic servo unit used for performing gear ratio control, clutch operation control and the like in a continuously variable transmission by using a solenoid valve.

[0002]

2. Description of the Related Art Conventionally, various continuously variable transmissions have been proposed for vehicles, etc., which are capable of continuously changing and outputting input rotation. For example, Japanese Unexamined Patent Publication No. 59-95722 discloses a vehicular use of a continuously variable transmission having a closed circuit composed of a constant discharge type hydraulic pump and a variable displacement hydraulic motor. In such a continuously variable transmission, the clutch control at the time of starting and stopping and the control of the gear ratio during traveling are often controlled by a servo unit based on the throttle opening degree, the vehicle speed, and the like. The clutch control is performed not only in the continuously variable transmission but also in the case of a gear type multi-speed transmission, and the clutch control may be performed by a servo unit.

As a method of controlling such a servo unit, hydraulic pressure is supplied to and discharged from the left and right cylinder chambers of the servo unit by using a solenoid valve, and the operation control of the servo unit is performed by an electric signal to the solenoid valve. I often do it. However, when a solenoid valve is used, there is a problem that if the solenoid valve malfunctions, the servo unit cannot be controlled. For this reason, conventionally, when the solenoid valve is malfunctioning, the servo unit is slowly moved to either one, thereby slowly moving the clutch to the OFF (release) or ON (engagement) side, for example. Various structures have been considered in which a so-called fail-safe is activated by changing the gear ratio to LOW or TOP.

For example, Japanese Patent Publication No. 60-249761 discloses that hydraulic pressure is supplied to and discharged from the left and right cylinder chambers of a servo cylinder for controlling the gear ratio of a continuously variable transmission through a four-way valve. It is disclosed that the operation of the four-way valve is controlled by using a solenoid valve. In this device, if the solenoid valve malfunctions due to a malfunction, etc., change the position of the four-way valve to a position to stop shifting, or to a position to supply / discharge hydraulic pressure via an orifice. The ratio is slowly moved until it becomes maximum (LOW) or minimum (TOP).

[0005]

However, if the gear shifting is stopped when a malfunction of the solenoid valve or the like occurs, if the malfunction occurs when the gear ratio is on the TOP side, the TOP side is affected. The gear ratio is maintained as it is. Therefore, even if the vehicle equipped with the continuously variable transmission is stopped thereafter for inspection or the like and the vehicle is restarted, the gear ratio is still held on the TOP side, and therefore the vehicle cannot be started. There is a problem.

In such a case, the vehicle is often stopped and inspected, and then the vehicle is often moved to a repair shop for repair or the like. There is a problem that it is inconvenient because it cannot be moved by itself. A similar problem also occurs when the gear ratio is changed to the maximum (TOP) side when the operation is defective. Further, the use of the 4-way valve has a problem that the control mechanism is complicated and tends to increase in size.

The same problem occurs when the clutch engagement control of the transmission is performed by the servo unit. In the case of the clutch engagement control servo unit, if the solenoid valve that controls the operation of the servo unit malfunctions and the servo unit is stopped and held as it is, the clutch will turn on (engage) and turn off. (release)
Alternatively, the clutch is held in either of the half-clutched states, which is unstable.

For this reason, it is usually constructed so that it is slowly changed to ON or OFF when the operation is defective, but when it is kept in the ON state,
When the engine is running, the driving force is always transmitted to the wheels, and there is a problem that the vehicle cannot be stopped unless the engine is stopped. further,
Once the engine is stopped, it cannot be restarted with the clutch on. Further, there is a problem that even if an attempt is made to pull the vehicle, the resistance is large and it is difficult to pull the vehicle in the clutch-on state.

In view of such a problem, the present invention provides a control device having a simple structure, in which a fail-safe function is activated when the solenoid malfunctions and the control target by the servo unit can be changed to a safe side. With the goal.

[0010]

As means for achieving the above object, in the electromagnetic control device for a servo unit according to the present invention, hydraulic oil of a predetermined hydraulic pressure is supplied to the rod side cylinder chamber constituting the servo unit. A first hydraulic pressure supply passage is connected to the head side cylinder chamber, and a second hydraulic pressure supply passage connected to the first hydraulic pressure supply passage is connected to the head side cylinder chamber through a first solenoid valve whose duty ratio is controlled to open and close. The chamber is also connected to a drain circuit via a second solenoid valve whose duty ratio is controlled to open and close.

Further, a first orifice having a predetermined flow passage area is provided in the second hydraulic pressure supply passage, and a flow passage area smaller than the predetermined flow passage area is provided in the flow passage from the second solenoid valve to the drain circuit. Is provided with a second orifice. Therefore, the first and second solenoid valves are both turned off due to malfunction or the like, and the first and second solenoid valves are turned off.
When the hydraulic pressure supply passage is opened, a pressure lower than the predetermined hydraulic pressure is generated in the head side cylinder chamber due to the action of the orifices having different areas as described above. as a result,
The piston slowly moves to either one of the stroke ends due to the difference between the pressing force acting on the piston by the low pressure hydraulic pressure and the pressing force acting on the piston by the predetermined hydraulic pressure in the rod side cylinder chamber.

The servo unit is used for gear shift control of a continuously variable transmission or clutch control of a transmission. When used for gear shift control of a continuously variable transmission, a piston is connected to a gear shift control mechanism, and the gear ratio is shifted from LOW to TOP by movement of the piston. When the piston is turned off and the piston is moved to the stroke end, the gear ratio is slowly changed to LOW. Further, when this is used for clutch control, the piston is connected to the clutch actuating mechanism, and the movement of the piston controls the engagement capacity of the clutch so as to continuously change from the full engagement state to the full release state. However, when both solenoid valves are turned off and the piston is moved to the stroke end as described above, the clutch slowly changes to the fully released state.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a hydraulic circuit of a continuously variable transmission including a servo unit controlled by an electromagnetic control device according to the present invention. In FIGS. 1 and 2, the oil passages 101 and 120 are connected to each other, and the links 39 and 88 are connected to each other. Together, these drawings show the entire hydraulic circuit.

The continuously variable transmission T has a constant displacement hydraulic pump P driven by an engine E through an input shaft 1 and a variable displacement hydraulic motor M having an output shaft 2 for driving wheels W.
And have. The hydraulic pump P and the hydraulic motor M include a first oil passage La that connects the discharge port of the pump P and the suction port of the motor M to the suction port of the pump P and the motor M.
The second oil passage Lb and the second oil passage Lb that communicate the discharge port of the above are connected to form a hydraulic closed circuit.

The discharge port of the charge pump 10 driven by the engine E is connected to a closed circuit via a charge oil passage Lh having a check valve 11 and a third oil passage Lc having a pair of check valves 3 and 3. ing. Therefore, the hydraulic oil pumped up from the oil tank 15 by the charge pump 10 and regulated by the charge pressure relief valve 12 acts on the low pressure side of the two oil passages La and Lb by the action of the check valves 3 and 3. Is supplied to the oil passage.

Further, the fourth oil passage Ld having the shuttle valve 4 having the high pressure and low pressure relief valves 6 and 7 and connected to the fifth and sixth oil passages Le and Lf connected to the oil sump 15 is the closed circuit. It is connected to the. This shuttle valve 4 is a 2-port 3-position switching valve,
And the second oil passages La and Lb are actuated according to the hydraulic pressure difference, and the high-pressure side oil passage of the first and second oil passages La and Lb is changed to the fifth oil passage.
The oil passage Le is communicated with, and the low pressure side oil passage is communicated with the sixth oil passage Lf. As a result, the relief hydraulic pressure of the high pressure side oil passage is regulated by the high pressure relief valve 6, and the relief hydraulic pressure of the low pressure side oil passage is regulated by the low pressure relief valve 7.

Between the first and second oil passages La and Lb, there is provided a seventh oil passage Lg which short-circuits both oil passages. The seventh oil passage Lg controls the opening of this oil passage. A clutch valve 5 composed of a variable throttle valve is provided. The clutch valve 5 is operated by a clutch servo unit 80 connected via a link 88. Therefore, by operating the clutch servo unit 80 to control the throttle amount of the clutch valve 5, it is possible to perform clutch control for controlling the transmission of the driving force from the hydraulic pump P to the hydraulic motor M.

An actuator that controls the displacement of the hydraulic motor M to control the gear ratio of the continuously variable transmission T is
The first and second shifting servo units 30 and 50 are connected by a link mechanism 45. The hydraulic motor M is a swash plate axial piston motor, and its capacity is controlled by controlling the swash plate angle by the shifting servo units 30 and 50.

The operation of the shifting servo units 30, 50 and the clutch servo unit 80 is performed by the controller 10
It is controlled by each pair of solenoid valves 151, 152 and 155, 156 whose duty ratio is controlled independently by a signal from 0. This controller 1
00 is the vehicle speed V, the engine speed Ne, the throttle opening θth, the swash plate inclination angle θtr of the hydraulic motor M, the accelerator pedal opening θacc operated by the driver, the atmospheric pressure Pat,
Signals indicating the oil temperature To, the water temperature Tw, and the clutch opening degree θcl are input, and control signals are output to the solenoid valves so that desired travel can be obtained based on these signals.

Below, each of the servo units 30 and 5 will be described.
The structure of 0.80 and its operation will be described in detail. First, the shifting servo unit 30 shown in FIGS. 3 and 4,
50 will be described. The link arms 47a in both figures are integrally connected, and the two figures are combined to show the shifting servo units 30 and 50.

The first servo unit 30 includes a high voltage line 1
20 are connected. The high pressure line 120 is connected to the fifth oil passage L from the closed circuit of the continuously variable transmission T via the shuttle valve 4.
The high-pressure hydraulic oil that is connected to e and is guided to the fifth oil passage Le is introduced into the first servo unit 30 via the high-pressure line 120, and the first servo unit 30 uses the hydraulic pressure of this high-pressure hydraulic oil. The swash plate angle of the hydraulic motor M is controlled. First
The speed changing servo unit 30 is connected to the second speed changing servo unit 50 via a connection link mechanism 45.

The first shifting servo unit 30 has a housing 31 having a connection port 31a to which the high voltage line 120 is connected, and a piston member 32 which is slidably inserted in the housing 31 in the left and right directions in the drawing. This piston member 3
2 has a spool member 34 concentric therewith and slidably fitted to the left and right. The piston member 32 includes a piston portion 32a formed at the right end and a piston portion 32a.
A cylindrical rod portion 3 which is concentric with and extends leftward from this
2b and. The piston portion 32a is fitted into a cylinder hole 31c formed in the housing 31, and the inside of the cylinder hole 31c is divided into two to divide the left and right cylinder chambers 35 and 36 into one.
Is formed. The rod portion 32b has a cylinder hole 31.
It is fitted into a rod hole 31d which is smaller in diameter than c and is concentric with it. The right cylinder chamber 35 is closed by the plug member 33a and the cover 33b, and the spool member 34 is disposed so as to penetrate therethrough.

The high pressure line 120 connected to the connection port 31a via the oil passage 31b is connected to the left cylinder chamber 35 formed by being partitioned by the piston portion 32a, and the piston member 32 is connected to the left cylinder chamber 35. The hydraulic pressure from the high-pressure line 120 introduced into the cylinder receives a pushing force to the right in the figure. A land portion 34a is formed at a tip end portion of the spool member 34 so as to be closely fitted to the spool hole 32d, and a diagonal portion 2a is formed on the right side of the land portion 34a.
The surface is scraped off over a predetermined axial dimension to form a recess 34b. A retaining ring 37 is fitted to the right side of the recess 34b and comes into contact with a retaining ring 38 fitted to the inner peripheral surface of the piston member 32 to prevent the retaining member 37 from coming off.

The piston member 32 includes a spool member 34.
According to the rightward movement of the right cylinder chamber 35 to the spool hole 3
The discharge passage 32e that can be opened to an oil sump (not shown) via 2d and the right cylinder chamber 35 through the recess 34b according to the leftward movement of the spool member 34.
A communication path 32c that can communicate with 6 is provided.

From this state, when the spool member 34 is moved to the right, the land portion 34a closes the communication path 32c and opens the discharge path 32e. Therefore, the pressure oil from the high-pressure line 120 flowing in via the oil passage 31b acts only on the left cylinder chamber 35, and moves the piston member 32 rightward so as to follow the spool member 34. Next, when the spool member 34 is moved to the left, the concave portion 34b causes the communication passage 32c to communicate with the right cylinder chamber 36, contrary to the above, and the land portion 3
4a closes the discharge path 32e. Therefore, the high-pressure oil acts on both the left and right cylinder chambers 35, 36,
Due to the difference in the pressure receiving area, the piston member 32 is moved leftward so as to follow the spool member 34.

When the spool member 32 is stopped halfway, the piston member 32 is brought into a hydraulic floating state due to the pressure balance between the left and right cylinder chambers 35 and 36, and stops at that position. In this way, the spool member 3
By moving 4 to the left and right, the piston member 32 can be moved following the spool member 34 using the hydraulic pressure of the high-pressure hydraulic oil from the high-pressure line 120.
As a result, the swash plate Mt of the hydraulic motor M connected to the piston member 32 via the link 39 can be rotated about its rotation axis Ms and its capacity can be variably controlled.

The spool member 34 is connected to the second shifting servo unit 50 via a link mechanism 45. The link mechanism 45 includes a first link member 47 having two substantially orthogonal arms 47a and 47b rotatable about a shaft 47c, and an arm 47 of the first link member 47.
The second link member 48 is pin-coupled to the tip of b. The upper end of the arm 47a is pin-connected to the right end of the spool member 34 of the first shifting servo unit 30, and the lower end of the second link member 48 is the second end.
It is pin-connected to the spool member 54 of the speed changing servo unit 50. Therefore, the second shifting servo unit 5
When the spool member 54 of 0 moves up and down, the spool member 34 of the first shifting servo unit 30 moves left and right.

The second shifting servo unit 50 has a port 51a to which the two hydraulic lines 102 and 104 are connected,
Housing 51 having 51b and this housing 51
A spool member 54 is slidably inserted in the upper and lower parts in the drawing.
Consists of. The spool member 54 has a piston portion 54a.
And a tip portion 54b that extends concentrically below the piston portion 54a, and a rod portion 54c that extends concentrically with the piston portion 54a above the piston portion 54a. Piston part 54a
Is a rod-side cylinder chamber that is fitted and inserted into a cylinder hole 51c formed by extending vertically in the housing 51, and that is located above the piston portion 54a and through which the rod portion 54c penetrates inside the cylinder chamber surrounded by the cover 55. 52 and a head-side cylinder chamber 53 located below the piston portion 54a. The tip portion 54b is fitted and inserted into an insertion hole 51d that is concentric with the cylinder hole 51c and extends downward.

A recess 54e having a tapered surface is formed in the tip 54b, and the spool 58a of the top position determination switch 58 projects into the recess 54e. The spool 58a is pushed up along the hydraulic motor M
It is possible to detect whether or not the gear ratio of 1 has been minimized.

The rod-side and head-side cylinder chambers 5 formed by being divided into two by the piston portion 54a.
2 and 53 are hydraulic lines 102 and 1 respectively
04 communicates with each other through the ports 51a and 51b. Therefore, the magnitude of the pressing force on the piston portion 54a, which is determined by the hydraulic pressure of the hydraulic oil supplied via the hydraulic lines 102 and 104 and the pressure receiving area where the piston portion 54a receives the hydraulic pressure in both cylinder chambers 52 and 53, is determined. Accordingly, the spool member 54 is moved up and down. The vertical movement of the spool member 54 is transmitted to the spool member 34 of the first speed changing servo unit 30 via the link mechanism 45 to move the spool member 34 left and right.

That is, the movement of the spool member 34 of the first shifting servo unit 30 is controlled by controlling the hydraulic pressure supplied through the hydraulic lines 102 and 104,
As a result, the piston member 32 is moved to control the swash plate angle of the hydraulic motor M to control the displacement of the motor M to control the gear ratio. Specifically, the second
By moving the spool member 54 of the speed changing servo unit 50 upward, the piston member 32 of the first speed changing servo unit 30 is moved to the right to reduce the swash plate angle and reduce the capacity of the hydraulic motor M to change the gear ratio. Can be made smaller.

From the port 51a to the rod side cylinder chamber 52
The hydraulic pressure of the hydraulic line 102 connected to the inside is the hydraulic oil in which the discharge oil of the charge pump 10 is regulated by the charge pressure relief valve 12 and introduced through the hydraulic lines 101 and 102. On the other hand, the hydraulic pressure of the hydraulic line 104 connected from the port 51b to the head side cylinder chamber 53 is the hydraulic pressure of the hydraulic line 103 having the first orifice 61 branched from the hydraulic line 102, which is first duty controlled
And the hydraulic pressure obtained by controlling the second solenoid valves 151 and 152.

The first solenoid valve 151 is connected to the hydraulic line 103 to the hydraulic line 10 having the first orifice 61.
The opening / closing control of the flow rate of the hydraulic oil to the No. 4 according to the duty ratio. The second solenoid valve 152 is the hydraulic line 104.
Is provided between the hydraulic line 105 that branches from the hydraulic line 105 and the hydraulic line 106 that communicates with the drain side through the second orifice 62, and the hydraulic oil flows from the hydraulic line 104 to the drain side according to a predetermined duty ratio. It is something to make. Therefore, the hydraulic lines 101, 102 correspond to the first hydraulic pressure supply passage described in the claims, and the hydraulic lines 103, 1
Reference numeral 04 corresponds to the second hydraulic pressure supply passage. Therefore, the charge pressure (constant pressure) regulated by the charge pressure relief valve 12 acts on the rod side cylinder chamber 52 via the hydraulic line 102. On the other hand, from the hydraulic line 104, the operation of the two solenoid valves 151, 152 causes
A pressure lower than the charge pressure is supplied to the head side cylinder chamber 53.

Since the pressure receiving area of the rod side cylinder chamber 52 is smaller than the pressure receiving area of the head side cylinder chamber 53, the force applied to the spool member 54 by the hydraulic pressure in both cylinder chambers 52, 53 is the rod side cylinder chamber. The oil pressure in the head-side cylinder chamber 53 is balanced with the oil pressure Pu in 52 when the oil pressure in the head-side cylinder chamber 53 is a predetermined value P _L (Pu> P _L ).
Therefore, the first and second solenoid valves 151, 1
By 52, by controlling the hydraulic pressure supplied from the hydraulic line 104 to the head-side cylinder chamber 53 so as to be larger than the predetermined value P _L, the spool member 54 is moved upward to reduce the swash plate angle of the hydraulic motor M It is possible to reduce the gear ratio. If the hydraulic pressure supplied to the head side cylinder chamber 53 is controlled to be lower than P _L , the spool member 54 can be moved downward to increase the swash plate angle of the hydraulic motor M and increase the gear ratio. ..

The solenoid valves 151 and 152 are driven and controlled by a signal from the controller 100. As can be seen from this, the controller 1
The two solenoid valves 151,
Only by controlling the operation of 152, the operation of the first and second speed changing servo units 30 and 50 is controlled, and the capacity of the hydraulic motor M and the speed ratio are controlled.

The above first and second solenoid valves 15
When the first and second orifices 61 and 62 arranged in the oil passage whose duty ratio is controlled by 1, 152 are both turned off due to malfunction of both solenoid valves 151 and 152 (both solenoid valves). 151,
This is for the purpose of fail-safe action in the case where both are in the open state. Therefore, the first
The flow passage area A1 of the orifice 61 is equal to the second orifice 62.
Is set larger than the flow passage area A2 (A1> A2), and its size is set as follows.

First, both solenoid valves 151 and 152
When both of them are turned off due to malfunctions due to a failure, poor energization, etc., the hydraulic oil in the hydraulic line 103 flows to the hydraulic line 104 via the first orifice 61, and the hydraulic oil in the hydraulic line 104 further. Flows from the hydraulic line 106 to the drain circuit (oil sump 15) via the second orifice 62. Here, since A1> A2, the hydraulic pressure Pa in the hydraulic line 104 is equal to the hydraulic line 10
The hydraulic pressure is lower than the hydraulic pressure Pu in 3, 102. Moreover,
The magnitude of this hydraulic pressure Pa can be arbitrarily set by the ratio of the flow passage areas A1 and A2 of both orifices 61 and 62. For example, when the ratio (A1 / A2) is increased, the hydraulic pressure Pa of the hydraulic line 104 approaches the hydraulic pressure Pu of the hydraulic line 102, and when the ratio (A1 / A2) is decreased, the hydraulic pressure Pa of the hydraulic line 104 approaches zero. It is much lower than the hydraulic pressure Pu of the line 102.

In this example, by adjusting the above ratio, both sources
Both the Renoid valves 151 and 152 are turned off
At times, the hydraulic pressure Pa of the hydraulic line 104 is the above-mentioned predetermined value.
Value P _LIt is set to have a slightly lower hydraulic pressure.
Both solenoid valves 151, 152 are OFF
If the rod of the second shifting servo unit 50
The hydraulic pressure Pu acts on the side cylinder chamber 52, and
This hydraulic pressure Pa acts on the da chamber 53. For this reason,
The hydraulic pressure received by the cooling member 54 is the rod-side cylinder chamber 5
The force acting from 2 becomes larger and the spool member 54
Is lowered and the gear ratio is increased (that is, LOW side
To shift).

However, the hydraulic pressure P in the rod side cylinder chamber 52
Since a is only slightly lower than the predetermined value P _{L, the} force that pushes down the spool member 54 is small, so that the spool member 54 is slowly moved downward, and the gear ratio is slowly shifted to the LOW side. With this configuration, for example, when both solenoid valves 151 and 152 are turned off due to a failure or the like during traveling, the gear ratio is slowly changed to LO.
The gear is shifted to the W side, and a fail-safe action is obtained. Further, when the solenoid valves 151 and 152 are malfunctioning by shifting to the LOW side,
Although the gear ratio remains LOW, the vehicle can be driven, and the vehicle can be driven by itself at the repair shop.

Next, the clutch servo unit 80 for controlling the operation of the clutch valve 5 will be described with reference to FIG. The unit 80 includes a cylinder member 81, a piston member 82 slidably inserted in the cylinder member 81 to the left and right in the drawing, and a cover member 85 attached to cover a cylinder chamber in which the piston member 82 is inserted. And a spring 87 for urging the piston member 82 to the left in the figure.
The piston 82a of the piston member 82 divides the cylinder chamber into two parts to form a head side cylinder chamber 83 having piston head surfaces facing each other and a rod side cylinder chamber 84 through which the rod 82b penetrates. Hydraulic lines 112, 110 via 86a, 86b
Are connected.

The charge pump 1 is connected to the hydraulic line 110.
The hydraulic oil in which the discharged oil of 0 is regulated by the charge pressure relief valve 12 is introduced through the hydraulic line 101. The oil pressure of the oil pressure line 104 is obtained by controlling the oil pressure of the oil pressure line 111 having the first orifice 65 branched from the oil pressure line 101 by the first and second solenoid valves 155 and 156 whose duty ratio is controlled. The first solenoid valve 156 controls the opening / closing of the flow rate of the hydraulic oil from the hydraulic line 111 having the first orifice 65 to the hydraulic line 112 according to the duty ratio. The second solenoid valve 155 is disposed between the hydraulic line 113 that branches from the hydraulic line 112 and the hydraulic line 114 that communicates with the drain side through the second orifice 66, and the drain line is drained from the hydraulic line 113 according to a predetermined duty ratio. Control the outflow of hydraulic oil to the side. This clutch servo unit 80
In the above, the hydraulic lines 101, 110 correspond to the first hydraulic pressure supply passage described in the claims, and the hydraulic line 11
1, 112 correspond to the second hydraulic pressure supply passage.

Therefore, the charge pressure relief valve 12 is installed in the rod side cylinder chamber 52 via the hydraulic line 110.
The charge pressure regulated by is applied by the two solenoid valves 15 from the hydraulic line 112.
By the operation of 5, 156, a pressure lower than the charging pressure is supplied to the head side cylinder chamber 83. Here, since the pressure receiving area of the rod side cylinder chamber 84 is smaller than the pressure receiving area of the head side cylinder chamber 83, the force applied to the piston member 82 by the hydraulic pressure in both the cylinder chambers 83 and 84 is the spring 87.
Even if the urging force of the head side cylinder chamber 83 is taken into consideration,
Is balanced at a predetermined value Ps (P1> Ps) lower than this.

For this reason, the hydraulic pressure P2 supplied from the hydraulic line 112 to the head side cylinder chamber 83 by the first and second solenoid valves 155 and 156 is set to the above predetermined value P.
If it is controlled to be larger than s, the piston member 82
Can be moved to the right, and the piston member 82 can be moved to the left by controlling the hydraulic pressure P2 supplied to the head side cylinder chamber 83 to be smaller than Ps. The movement of the piston member 82 in the left-right direction is performed by the link mechanism 88.
Is transmitted to the clutch valve 5 via.

The clutch valve 5 comprises a fixed member 5a having a first valve hole 5b and a rotary member 5c having a second valve hole 5d rotatably arranged in the fixed member 5a. The arm 5e connected to the piston member 82 is connected to the link mechanism 88.
The rotating member 5c is rotated with the movement of. Rotating member 5
When c is rotated, the first and second valve holes 5b, 5d
The communication opening of changes from fully open to fully closed. As shown in the figure, with the piston member 82 moved to the maximum left,
The communication opening of the clutch valve 5 is fully opened.
As the piston member 82 is moved to the right, the communication opening gradually changes until it is fully closed.

Here, the first valve hole 5b is used for the continuously variable transmission T.
Since the second valve hole 5d communicates with the first oil passage La and the second oil passage Lb forming the closed circuit of the above, the communication opening degree of the first and second valve holes 5b, 5d is changed. By doing so, it is possible to change the opening degree of the seventh oil passage Lg, which is a short-circuit passage of the first and second oil passages La and Lb, and thereby clutch control is performed. That is, clutch control is performed by controlling the duty ratio of the first and second solenoid valves 155 and 156 based on the signal from the controller 100.

The first and second orifices 65, 66 arranged in the hydraulic lines 111, 114 are also the orifices 61, 6 in the speed changing servo units 30, 50.
Similar to the case of 2, both solenoid valves 155, 156
It is for fail-safe in case of malfunction of. Therefore, the flow passage area A3 of the first orifice 65 is
Is larger than the flow passage area A4 of the second orifice 66, and the ratio (A3 / A4) of both areas is set to a desired value.

In this example, both solenoid valves 15
The area ratio (A1 / A2) is set such that the hydraulic pressure P2 of the hydraulic line 112 is slightly lower than the predetermined value Ps when both 5 and 156 are turned off.
Therefore, when the solenoid valves 155 and 156 are turned off due to a failure or the like, the piston member 82 of the clutch servo unit 80 is slowly moved to the left. As a result, the solenoid valves 155, 156 for controlling the clutch servo unit 80 are turned off due to malfunction during traveling.
When it becomes FF, the clutch valve 5 is gradually opened.

In this way, when the solenoid valve is not operating properly, the clutch valve 5 is opened and the clutch is closed.
Since it is FF, the vehicle can be stopped by stepping on the brake, and the fail-safe function can be secured. Since the clutch is still in the OFF state even after this, the vehicle cannot be self-propelled, but it can be easily towed. In such a case, the vehicle can be towed to a repair shop.

[0049]

As described above, according to the present invention,
The flow passage area of the first orifice provided in the second hydraulic pressure supply passage and the flow passage area of the second orifice provided in the flow passage from the second solenoid valve to the drain circuit have a predetermined relationship. When both the first and second solenoid valves are turned off due to a malfunction or the like and the first and second hydraulic pressure supply paths are opened, a low pressure hydraulic pressure is generated in the head side cylinder chamber by the action of both orifices. , The piston is slowly moved to one of the stroke ends by the difference between the pressing force acting on the piston by this low hydraulic pressure and the pressing force acting on the piston by the predetermined hydraulic pressure in the rod side cylinder chamber. .. Therefore, in the servo unit of the present invention, the fail safe can be activated with a relatively simple structure.

This servo unit is used for the shift control of the continuously variable transmission or the clutch control of the transmission. When used for gear shift control of a continuously variable transmission, the piston of the servo unit is connected to the gear shift control mechanism, and the gear ratio is shifted from LOW to TOP by movement of the piston. In this case, when both solenoid valves are off and the piston is moved to the stroke end as described above, the gear ratio is slowly changed to LOW. With this configuration, for example, when both solenoid valves are turned off due to a failure or the like during traveling, the gear ratio is slowly shifted to the LOW side, and fail-safe can be activated. Further, by shifting to the LOW side, it is possible to drive the vehicle even though the gear ratio remains LOW, and when malfunction of the solenoid valve occurs, the vehicle can be driven by itself at the repair shop. Become.

On the other hand, when the servo unit of the present invention is used for clutch control, the piston is connected to the clutch actuating mechanism and the engagement capacity of the clutch is continuously changed by the movement of the piston to the full engagement state and the colorful release state. To be controlled. In this case, when both solenoid valves are turned off and the piston is moved to the stroke end as described above, the clutch slowly changes to the fully released state. With this configuration, when the solenoid valve is not operating properly, the clutch valve 5 is opened and the clutch is turned off. Therefore, it is sufficient to step the brake to stop the vehicle, and the fail-safe function can be secured. The clutch will be off after this
Since the vehicle is in the state, the vehicle cannot be self-propelled, but it is easy to tow the vehicle. In such a case, the vehicle can be towed to the repair shop.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a continuously variable transmission including a control device according to the present invention.

FIG. 2 is a hydraulic circuit diagram of a continuously variable transmission including a control device according to the present invention.

FIG. 3 is a cross-sectional view of a first shift servo unit.

FIG. 4 is a cross-sectional view of a second shift servo unit.

FIG. 5 is a sectional view of a clutch servo unit.

[Explanation of symbols]

 4 Shuttle valve 5 Clutch valve 30, 50 Shift servo unit 61, 62, 65, 66 Orifice 80 Clutch servo unit 100 Controller 151, 152, 155, 156 ... Solenoid valve E Engine T Continuously variable transmission

Claims (2)

[Claims] 1. An electromagnetic control device of a shift servo unit for performing this gear ratio control in a continuously variable transmission capable of continuously changing the gear ratio from LOW to TOP, wherein the servo unit is a cylinder. A piston that is slidably fitted into a cylinder chamber formed in the cylinder, the cylinder chamber being defined by the piston.
It is divided into a rod-side cylinder chamber through which the piston rod passes, and a head-side cylinder chamber that has a piston head surface facing and has a larger piston pressure receiving area than the rod-side cylinder chamber. A first hydraulic pressure supply passage to which hydraulic oil is supplied is connected, and a second hydraulic pressure supply passage connected to the first hydraulic pressure supply passage is connected to the head side cylinder chamber via a first solenoid valve whose duty ratio is opened and closed. And the head side cylinder chamber is also connected to a drain circuit via a second solenoid valve whose duty ratio is controlled to be opened and closed, and a first orifice having a predetermined flow passage area is provided in the second hydraulic pressure supply passage. A second orifice having a flow passage area smaller than the predetermined flow passage area is arranged in the flow passage from the second solenoid valve to the drain circuit. When both the first and second solenoid valves are turned off and the first and second hydraulic pressure supply passages are opened, the pressing force acting on the piston by the hydraulic pressure generated in the head side cylinder chamber. And the pressing force acting on the piston by the predetermined hydraulic pressure in the rod side cylinder chamber causes the piston to slowly move to one of the stroke ends, and this movement causes the shift control unit to control the shift. An electromagnetic control device for a transmission servo unit, characterized in that the ratio is slowly changed to LOW. 2. A transmission having a clutch whose engagement capacity can be continuously controlled from a full engagement state to a full disengagement state, and an electromagnetic force of a clutch servo unit for controlling the engagement capacity of the clutch. In the control device, the servo unit includes a cylinder and a piston slidably fitted in a cylinder chamber formed in the cylinder, and the cylinder chamber is formed by the piston.
It is divided into a rod-side cylinder chamber through which the piston rod passes, and a head-side cylinder chamber that has a piston head surface facing and has a larger piston pressure receiving area than the rod-side cylinder chamber. A first hydraulic pressure supply passage to which hydraulic oil is supplied is connected, and a second hydraulic pressure supply passage connected to the first hydraulic pressure supply passage is connected to the head side cylinder chamber via a first solenoid valve whose duty ratio is opened and closed. And the head side cylinder chamber is also connected to a drain circuit via a second solenoid valve whose duty ratio is controlled to be opened and closed, and a first orifice having a predetermined flow passage area is provided in the second hydraulic pressure supply passage. A second orifice having a flow passage area smaller than the predetermined flow passage area is arranged in the flow passage from the second solenoid valve to the drain circuit. When both the first and second solenoid valves are turned off and the first and second hydraulic pressure supply passages are opened, the pressing force acting on the piston by the hydraulic pressure generated in the head side cylinder chamber. And the pressing force acting on the piston by the predetermined hydraulic pressure in the rod-side cylinder chamber causes the piston to slowly move to one of the stroke ends, and the clutch controlled by the clutch servo unit by this movement. The electromagnetic control device for a transmission servo unit, wherein the engagement capacity of the transmission slowly changes to a fully released state.