JPH0637234Y2 - Lock-up control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a lockup control device for a continuously variable transmission.

(B) Conventional Technology As a conventional lockup control device for a continuously variable transmission, there is, for example, one disclosed in Japanese Patent Application Laid-Open No. 57-161360.
This lockup control device has a lockup valve that can be switched by using the hydraulic pressure in the drive pulley cylinder chamber as a pilot pressure, and the lockup clutch is activated when the hydraulic pressure in the drive pulley cylinder chamber is low (when the reduction ratio is large). When the hydraulic pressure in the drive pulley cylinder chamber is high (when the reduction ratio is small), the lockup clutch is engaged so that the lockup clutch is engaged.

(C) Problems to be solved by the invention However, such a conventional lock-up control device for a continuously variable transmission is designed so that the operating state of the lock-up clutch is switched only by the hydraulic pressure in the drive pulley cylinder chamber. Therefore, if the reduction ratio becomes small at low vehicle speed, the lock-up clutch may be engaged, and the torque fluctuation of the engine is mechanically input to the continuously variable transmission, causing vibration and worsening drivability. There is a problem.

For the case of a stepped automatic transmission, refer to US Pat.
No. 52352 shows a phase valve that supplies the governor pressure to the lockup switching valve when the third speed is reached.
That is, this phase valve controls the output of the governor pressure by switching depending on the balance between the second speed pressure and the third speed pressure, thereby switching the operation of the lockup switching valve and switching the lockup clutch at the third speed. Make it possible to conclude. However, such a phase valve cannot be applied to a continuously variable transmission in which the third speed pressure or the like does not exist, and if a valve that is switched by a hydraulic pressure that does not uniquely correspond to the reduction ratio is used, it will lock as desired. It is not possible to control the engagement of the up clutch.

The present invention aims to solve such problems.

(D) Means for solving the problem The present invention is to control the output of the governor pressure by the governor pressure cut valve that operates accurately corresponding to the reduction ratio.
The above problems are solved. That is, the lockup control device for a continuously variable transmission according to the present invention includes a governor valve (122) that generates a governor pressure corresponding to a vehicle speed, a throttle valve (110) that generates a throttle pressure corresponding to an engine load,
Outputs from the governor pressure cut valve (109) and the governor pressure cut valve (109) that outputs the governor pressure when the reduction ratio is smaller than the specified value and stops the output of the governor pressure when the reduction ratio is larger than the specified value. And a lockup switching valve (120) for switching and controlling the operation of the lockup clutch based on the hydraulic pressure and the throttle pressure, and the spool (141) of the governor pressure cutoff valve (109) is It is connected to the movable cone member (22) of the drive pulley or driven pulley that moves in the axial direction according to the reduction ratio of the continuously variable transmission so as to move integrally in the axial direction, and by the movement of this spool (141). The governor pressure output and stop are controlled as described above,
When the reduction ratio is small and the governor pressure is smaller than the throttle pressure, the lockup clutch is released. The reference numerals in the above parentheses indicate the corresponding members of the embodiments described later.

(E) Action Due to the action of the governor pressure cut valve, the governor pressure is not supplied to the lockup switching valve when the reduction ratio is large. Therefore, the lockup switching valve is always positioned on the lockup release side due to the action of the throttle pressure and the spring. Therefore, when the reduction gear ratio is larger than the predetermined value, the lockup clutch is always released. The lockup switching valve is controlled by the governor pressure and the throttle pressure, and the lockup clutch is released when the vehicle speed is low and the throttle opening is large (when the governor pressure is smaller than the throttle pressure). This makes it possible to prevent vibration. Since the spool of the governor pressure cut valve is configured to move integrally with the movable conical member of the drive pulley or the driven pulley in the axial direction, it can be reliably operated at a predetermined reduction ratio without being affected by fluctuations in hydraulic pressure. Switch. Therefore, the engagement / disengagement of the lockup clutch can be accurately controlled.

(F) Embodiment FIG. 2 shows an electric power transmission mechanism of a continuously variable transmission. This continuously variable transmission includes a fluid coupling 12, a forward / reverse switching mechanism 15,
It has a V-belt type continuously variable transmission mechanism 29, a differential device 56, and the like, and can transmit the rotation of the output shaft 10a of the engine 10 to the output shafts 66 and 68 at a predetermined reduction ratio and rotation direction. This continuously variable transmission includes a fluid coupling 12 (having a release pressure chamber 12a, an apply pressure chamber 12b, a pump impeller 12c, a turbine runner 12d, etc.), a rotary shaft 13, and a drive shaft 1.
4, forward / reverse switching mechanism 15, drive pulley 16 (fixed cone plate 1
8, drive pulley cylinder chamber 20 (chamber 20a, chamber 20b), movable cone plate 22, groove 22a, etc.), planetary gear mechanism 17 (sun gear 19, pinion gear 21, pinion gear 23, pinion carrier 25, internal gear 27) Etc.), V-belt 24, driven pulley 26 (consisting of fixed conical plate 30, driven pulley cylinder chamber 32, movable conical plate 34, etc.), driven shaft 28, forward clutch 40, drive gear 46, idler gear 48, reverse drive. The brake 50, idler shaft 52, pinion gear 54, final gear 44, pinion gear 58, pinion gear 60, side gear 62, side gear 64, output shaft 66, output shaft 68, etc. The description is omitted. Regarding the structure of the part of which description is omitted, Japanese Patent Application No. 59-226706 (Japanese Patent Application Laid-Open No. 61-105351) filed by the applicant of the present invention
No.).

FIG. 1 shows a hydraulic control device including a lockup pressure control device for a continuously variable transmission according to the present invention. In the present invention, the governor pressure cut valve 109, the lock-up switching valve 120, and the like are the main constituent elements. First, all the valves and the like that make up the hydraulic control device will be briefly described.

This hydraulic control device includes a line pressure regulating valve 102, a shift control valve 1
04, shift command valve 106, reduction ratio detection valve 108, governor pressure cut valve 109, throttle valve 110, manual valve 112, ND select valve 114, NR select valve 116, coupling pressure regulating valve 118,
Lockup switching valve 120, governor valve 122, pilot valve 12
4, solenoid 126 and the like.

The line pressure regulating valve 102 is a valve that regulates the hydraulic pressure (line pressure) of the oil passage 202 to which the oil discharged from the oil pump 128 is supplied. The line pressure is adjusted according to the throttle pressure supplied from the oil passage 204 and the pressure corresponding to the reduction ratio supplied from the oil passage 226, and in the lockup state, the supply of the hydraulic pressure from the oil passage 224 is stopped and the line The pressure drops.

The shift control valve 104 is a valve that realizes a desired reduction ratio by controlling the hydraulic pressure supplied to the drive pulley cylinder chamber 20 and the driven pulley cylinder chamber 32 via oil passages 260 and 262, respectively. The spool 132 of the shift control valve 104 is connected to the spool 136 of the deceleration command valve 106 and the reduction ratio detection member 14 by a link 134.
It is connected to 0, and its position is controlled by both of them.

The shift command valve 106 is a valve that controls the shift control valve 104 via the link 134. The spool 136 of this shift command valve 106
Is controlled in accordance with the governor pressure acting from the oil passage 234 and the throttle pressure acting from the oil passage 204. The hydraulic pressure is supplied from the oil passage 210 when the manual valve 112 is in the L range, and is controlled so that the reduction ratio is larger than that in the D range.

The reduction gear ratio detection valve 108 is a valve that regulates the hydraulic pressure according to the axial position of the reduction gear ratio detection member 140 using a constant pressure of the oil passage 230 as a hydraulic pressure source and outputs the oil pressure to the oil passage 226. Since the reduction ratio detection member 140 meshes with the groove 22a of the movable conical plate 22 of the drive pulley 16 and moves in the axial direction following this, the reduction ratio detection valve 140
The hydraulic pressure adjusted by 108 becomes the hydraulic pressure corresponding to the reduction ratio (pressure corresponding to the reduction ratio).

In the governor pressure cut valve 109, the spool 141 is formed integrally with the reduction ratio detection member 140, and the spool 141 is a land 141a.
It has a land 141b and a land 141b, by which the connection state of the oil passage 502 and the oil passage 234 can be switched, so that, as will be described later, the lockup is always released when the reduction ratio is large. Be seen.

The throttle valve 110 regulates the throttle pressure according to the throttle opening by using the line pressure of the oil passage 202 as a hydraulic pressure source and adjusts the oil passage 204.
It is a valve that outputs to. Throttle displacement is spool 161
Is transmitted to the spool 165 via the spring 163.
Is input to adjust the hydraulic pressure (throttle pressure) corresponding to the force of the spring 163.

The manual valve 112 changes the throttle pressure supplied from the oil passage 204 to the oil passages 206, 20 according to the selected position of the spool 150.
It is a valve that distributes to 8 and 210. As a result, the operation of the forward clutch 40 and the reverse brake 50 can be controlled to switch between forward and reverse.

For the ND select valve 114, the manual valve 112 is from the N range to D
Forward clutch that is engaged when the range is switched
It is a valve that eases the engagement of 40 and reduces select shock. That is, when the throttle pressure of the oil passage 204 is lower than a predetermined value, the lower half state in the figure is applied to supply the hydraulic pressure to the forward clutch 40 through the orifice 212, and when the throttle pressure is higher than the predetermined value. In the upper half of the figure, the hydraulic pressure is supplied without being affected by the orifice 212 at the initial stage, and when the hydraulic pressure rises to some extent, the lower half of the figure is reached and the hydraulic pressure is increased through the orifice 212. As a result, the forward clutch 40 is engaged while the flow rate is controlled before the engine torque increases.

The NR select valve 116 is for reducing the select shock when the shift operation mechanism 112 is operated from the N range to the R range, and is structurally similar to the ND select valve 114. As a result, the hydraulic pressure supplied to the reverse brake 50 is controlled.

Coupling pressure regulator valve 118 is a fluid coupling 12
It is a valve that regulates the hydraulic pressure supplied to. That is, the coupling pressure regulating valve 118 regulates a constant hydraulic pressure using the hydraulic pressure of the oil passage 222 as a hydraulic pressure source, and supplies this to the oil passage 273.

The lockup switching valve 120 is a valve that controls the lockup operation of the fluid coupling 12. That is, the oil passage
The lockup switching valve 120 switches between the upper half position and the lower half position in accordance with the hydraulic pressure (governor pressure) supplied from 502 and the throttle pressure supplied from the oil passage 204, and the oil passage is provided in the lower half position. Hydraulic coupling of 273 through oil passage 275 and fluid coupling
It is supplied to the 12 release pressure chambers 12a to be in a fluid coupling state, and in the upper half position, the oil pressure of the oil passage 273 is changed to the oil passage 277.
Is supplied to the apply pressure chamber 12b of the fluid coupling 12 through the lockup mechanism.

The governor valve 122 is a valve that uses the throttle pressure in the oil passage 204 as a hydraulic pressure source to generate a governor pressure corresponding to the vehicle speed. That is, the entire governor valve 122 rotates together with the driven pulley 26, regulates the hydraulic pressure corresponding to the centrifugal force acting on the spool, and outputs this to the oil passage 234.

The pilot valve 124 is a valve that regulates a constant hydraulic pressure by using the line pressure of the oil passage 202 as a hydraulic pressure source and supplies it to the reduction ratio detection valve 108 and the solenoid 126 via the oil passage 230.

The solenoid 126 can switch the opening / closing of the opening 181 of the oil passage 281 branched from the oil passage 230 via the orifice 283,
A valve that closes the opening 181 when it is on and opens the opening 181 when it is off, and is normally on only when the oil temperature detected by the oil temperature switch 185 is lower than a predetermined value. When the solenoid 126 is turned off, the opening 181 is opened and the oil pressure in the oil passage 281 is discharged, so that the lockup switching valve 120 is located on the lockup release side. That is, the solenoid 126 is for releasing the lockup when the temperature is low.

In addition to the above, this hydraulic control device has a cooler 952,
It has a line pressure check valve 954, a fluid coupling check valve 956, a cooler check valve 958, and the like.

Next, the lockup switching valve 120 and the governor pressure cut valve 109 directly related to the present invention will be described in more detail.

The lockup switching valve 120 presses the valve hole 402 having nine ports 402a to 402i, the spool 404 having seven lands corresponding to the valve hole 402, and the spool 404 leftward in FIG. Consisting of a spring 406. The ports 402a and 402c are connected to the throttle valve 110 via the oil passage 204. The port 402b communicates with the oil passage 281.
The port 402d is connected to the oil passage 224. The port 402e is a drain port. The port 402f is connected to the release pressure chamber 12a of the fluid coupling 12 via the oil passage 275. The port 402g is connected to the coupling pressure regulating valve 118 via the oil passage 273. The port 402h is connected to the apply pressure chamber 12b of the fluid coupling 12 via the oil passage 227. The port 402i is connected to the port 412b of the governor pressure cut valve 109 via the oil passage 502.

The governor pressure cut valve 109 includes a valve hole 412 having three ports 412a to 412c (which is concentric with the valve hole of the throttle valve 108) and a spool 14 having lands 141a and 141b.
1 (This is configured integrally with the reduction ratio detection member 140)
And consists of. The port 412a is connected to the governor pressure oil passage 234. The port 412b is connected to the port 402i of the lockup switching valve 120 via the oil passage 502. Port 4
12c is a drain port. The reduction ratio detecting member 140 is coupled to the movable conical plate 22 of the drive pulley 16 so as to be movable only in the axial direction together as described above.

Next, the operation of this embodiment will be described. Shift command valve 10
The position of the spool 136 of 6 is determined according to the balance between the governor pressure from the oil passage 234 and the throttle pressure from the oil passage 204. The movement of the spool 136 is transmitted to the spool 132 of the shift control valve 104 via the link 134, whereby the hydraulic pressure supplied to the drive pulley cylinder chamber 20 and the driven pulley cylinder chamber 32 is controlled, and the reduction gear ratio becomes a predetermined state. Is set. As a result, the movable cone plate 22 of the drive pulley 16 moves to a predetermined position. The movement of the movable cone plate 22 depends on the reduction ratio detecting member 140.
Is converted to the axial movement of. That is, as the reduction gear ratio becomes larger, the reduction gear ratio detection member 140 moves to the right in FIG.

When the reduction gear ratio is larger than a predetermined value, the reduction gear ratio detection member 14
The port 012 and the spool 141 integrated therewith are in the state of the lower half in the figure, and the communication between the port 412a and the port 412b is blocked, and the port 412b communicates with the drain port 412c. For this reason
The hydraulic pressure of 502 is discharged, and the port of lockup switching valve 120
No hydraulic pressure acts on the 402i. Therefore, the spool 404 of the lockup switching valve 120 is brought into the lower half state in the figure by the throttle pressure acting on the port 402a and the force of the spring 406, the port 402g and the port 402f communicate with each other, and the fluid passage 275 connects with the fluid cup. Hydraulic pressure is supplied to the release pressure chamber 12a of the ring 12. As a result, the lockup is released.
That is, when the reduction gear ratio is larger than the predetermined value, the lockup is released. Since the predetermined value of the reduction ratio is detected by the reduction ratio detecting member 140, the lockup clutch release can be easily performed by changing the mounting position of the connecting portion of the drive pulley 16 with the movable conical plate 22. The characteristics of can be changed.

When the reduction gear ratio is smaller than a predetermined value, the reduction gear ratio detection member 14
0 and the spool 141 integrated therewith are in a state like the upper half in the figure, the port 412a and the port 412b communicate with each other, and the oil passage 50
Governor pressure is supplied to 2. This governor pressure acts on the port 402i of the lockup switching valve 120, so that the spool 404
Is switched by the balance between the force of the governor pressure of the port 402i, the force of the throttle pressure of the port 402a, and the force of the spring 404. That is, when the governor pressure is relatively lower than the throttle pressure, the lock is released in the lower half of the figure, and conversely, when the governor pressure is relatively higher than the throttle pressure, In the half state, the hydraulic pressure acts on the apply pressure chamber 12b of the fluid coupling 12 and the lockup state occurs. As a result, the lockup state is set in a range in which vibration does not occur depending on the engine load and the vehicle speed, and the lockup is released in the region where the reduction ratio is large as described above.

(G) Effect of the Invention As described above, according to the present invention, the governor pressure cut valve cuts off the supply of the governor pressure when the reduction ratio is large. The lockup clutch is released to prevent vibration. In addition, the governor pressure was smaller than the throttle pressure even when the reduction ratio was small (the reduction ratio was small at low vehicle speeds).
Occasionally, the lockup clutch is released to prevent vibration. Since the spool of the governor pressure cut valve is designed to move integrally with the movable conical member of the drive pulley or the driven pulley in the axial direction, the lockup clutch can always be engaged and released accurately without being affected by fluctuations in hydraulic pressure. Can be controlled.

[Brief description of drawings]

FIG. 1 is a diagram showing a hydraulic control device having a lockup control device for a continuously variable transmission according to the present invention, and FIG. 2 is a diagram showing a power transmission mechanism of the continuously variable transmission. 12 ... Fluid coupling (fluid transmission device), 22 ... Movable cone member, 109 ... Governor pressure cut valve, 110 ... Throttle valve, 120 ... Lockup switching valve, 122 ... Governor valve, 141 ...
spool.

Claims (1)

[Scope of utility model registration request] 1. A lockup control device for a continuously variable transmission equipped with a hydraulic power transmission device having a lockup clutch, and a governor valve for generating a governor pressure corresponding to a vehicle speed and a throttle for generating a throttle pressure corresponding to an engine load. Output from the valve, the governor pressure cut valve that outputs the governor pressure when the reduction ratio is smaller than the specified value, and stops the output of the governor pressure when the reduction ratio is greater than the specified value, and the governor pressure cut valve. A lockup switching valve for switching and controlling the operation of the lockup clutch on the basis of the hydraulic pressure and the throttle pressure, and the spool of the governor pressure cut valve has a spool according to the reduction ratio of the continuously variable transmission. It is connected to the movable conical member of the driving pulley or the driven pulley that moves in the axial direction by the axial movement of the spool. It is characterized in that the lockup clutch is disengaged when the output and stop of the internal pressure are controlled as described above, and when the reduction ratio is small and the governor pressure is smaller than the throttle pressure. Lock-up control device for continuously variable transmission.