JPH07113409B2 - Lockup clutch hydraulic controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement for eliminating fluctuations in a lockup initial hydraulic pressure of a lockup clutch configured so that an internal pressure of a torque converter acts on a piston back pressure portion. .

[Prior Art] FIG. 4 shows a conventional lockup clutch control system. In this control system, a lockup clutch 1, a torque converter 2 (hereinafter abbreviated as torque converter), a transmission tank 3, a strainer 4, a hydraulic pump 5, a main relief valve 6, a torque converter relief valve 7, a rear brake cooling 8, an oil cooler 9 are provided. , Oil filter 10, cooling relief valve 11, lubrication relief valve 12, transmission lubrication section 13, lockup modulation valve 14 and solenoid valve
15 and the like, the lockup modulation valve 14 is operated via the solenoid valve 15 to perform engagement and disengagement of the lockup clutch 1 and gradually increase hydraulic pressure.

FIG. 5 shows a time-dependent characteristic of the lock-up clutch hydraulic pressure during shifting in the conventional system.

That is, in this system, the solenoid of the solenoid valve 15 is first locked up “OFF” when shifting.
, The solenoid valve 15 is opened as shown in FIG. 4, the pilot hydraulic pressure passing through the valve 15 causes the spool of the modulation valve 14 to move to the right, and the valve 14 is closed as shown in FIG. Then, the oil in the lockup clutch 1 is drained (time t ₁ ).

Then, after a predetermined lockup delay time td at which the lockup is kept off, the solenoid valve 15
A lock-up “ON” signal is sent to the solenoid of (time t ₂ ). As a result, the solenoid valve 15 is switched to the closed state, and the hydraulic oil pushing the spool of the modulation valve 14 is drained through the solenoid valve 15. Therefore, the hydraulic pressure that pushes the spool of the valve 14 to the right becomes zero, the spool is pushed to the left by the spring 17, and the valve 14 is opened. As a result, the oil from the pump 5 passes through the valve 14 and the lockup clutch 1
And the clutch 1 is filled with oil after the filling time tf has elapsed. At this time, the valve outlet pressure is piloted on the left pressure receiving surface of the valve 14, and the spring 17 is provided on the right side of the valve 14, so the valve outlet pressure is the left pressure receiving area A of the spool and the pressing force of the spring 17. (Kx, K: spring constant x: initial displacement) is balanced by the initial pressure P ₀ (＝ Kx /
A) is set (time t ₂ ). After this, the spring 17 is gradually displaced from the initial displacement state by the hydraulic pressure via the orifice 18, and the valve outlet hydraulic pressure rises with this displacement (dotted line in FIG. 5). On the other hand, the hydraulic pressure in the lockup clutch 1 is almost zero during the filling period tf, and rises to the initial hydraulic pressure Pa at the same time as the filling is completed, and then gradually increases (time t ₃ ).

The above is the operation of the modulation valve 14 at the time of shifting. The initial hydraulic pressure Pa obtained by the modulation valve 14 and its gradually increasing characteristic are fixedly set by the mounting load Kx of the spring 17, the pressure receiving area A of the spool, and the like.

By the way, in this control system, the lock-up clutch 1 has a structure in which the torque converter 2 is oil-immersed, and the piston back pressure portion of the lock-up clutch 1 is connected to the torque converter 2 as shown by the oil passage 16. The internal pressure Pt acts. Therefore, in this system, for example, at the time when the clutch hydraulic pressure P reaches the initial hydraulic pressure Pa, the lockup clutch 1 is actually a differential pressure obtained by subtracting the torque converter internal pressure Pt from the initial clutch pressure Pa as shown in FIG.
The lockup clutch 1 operates with Ps (= Pa−Pt). Therefore, when the lockup clutch 1 is engaged, a hydraulic pressure higher than the torque converter internal pressure Pt must be applied.
Does not fill or engage. The differential pressure Ps when the clutch hydraulic pressure P reaches the initial hydraulic pressure Pa is hereinafter referred to as lockup initial hydraulic pressure.

For this reason, in this conventional device, an initial pressure Pa that is somewhat higher than the torque converter internal pressure Pt is set, and the clutch pressure is gradually increased from this initial pressure Pa.

[Problems to be Solved by the Invention] By the way, the internal pressure Pt of the torque converter fluctuates due to changes in the engine rotation. Therefore, in this conventional system, the lock-up initial hydraulic pressure Ps changes with the fluctuation of the torque converter internal pressure Pt. That is, in this system, since the clutch initial pressure Pa is fixed, for example, the torque converter internal pressure is
If Pt increases, the lockup initial hydraulic pressure Ps decreases.

As described above, in this conventional device, the lock-up initial hydraulic pressure Ps fluctuates according to the fluctuation of the internal pressure of the torque converter, so that the clutch engagement timing (filling time) varies, the shift shock is large, and the filling shock occurs in an extreme case. There was an inconvenience such as not doing.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a lock-up clutch hydraulic control device that prevents fluctuations in the lock-up initial hydraulic pressure corresponding to fluctuations in the internal pressure of the torque converter and reduces shift shock. is there.

[Means for Solving the Problems] In the present invention, the piston back pressure portion is provided with a lock-up clutch in which the internal pressure of the torque converter is actuated to perform engagement drive in accordance with the supplied hydraulic pressure. A lockup clutch hydraulic control device for controlling hydraulic pressure supplied to a clutch, wherein a first input port communicating with a hydraulic pump, an output port communicating with the lockup clutch, and a first input port and the output port are formed. And a second input port located in front of this orifice. When a differential pressure is not generated across the orifice, the spool is closed by the force of a spring provided at one end of the spool. As a result, the second input port communicates with the output port via the orifice, and the differential pressure is generated. Preparative a flow control valve for communicating said first and second input ports to the output port through the orifice in the open, and the valve inlet communicating with the hydraulic pump,
The flow control valve includes a spool having a valve outlet communicating with a second input port of the flow control valve, and a hydraulic pressure before the orifice of the flow control valve is applied to one pressure receiving surface of the spool and the other pressure receiving side of the spool is received. A pressure control valve that presses a surface with an actuator that generates a thrust corresponding to an electric command, and a filling control that detects that the spool of the flow control valve is changed from open to closed and outputs a filling end signal when the closed state is detected. When engaging the end detection means and the lockup clutch, an electric command corresponding to a predetermined lockup clutch initial hydraulic pressure is given to the actuator of the pressure control valve to communicate the valve inlet of the pressure control valve with the valve outlet. At the same time, when a filling end detection signal is output from the filling end detection means thereafter, the actuator of the actuator is pushed. With a control means for supplying to the actuator an electric command sequentially increasing, so that the action of the internal pressure of the torque converter to the actuator side pressure receiving surface of the spool of the pressure control valve.

[Operation] Since the internal pressure Pt of the torque converter is fed back to the pressure control valve, the lockup clutch hydraulic pressure is always biased by the internal pressure of the torque converter. Therefore, the torque converter internal pressure acting on the piston back pressure portion of the lockup clutch and the torque converter internal pressure included in the hydraulic pressure acting on the lockup clutch are canceled out, and the fluctuation of the torque converter internal pressure is locked up. It has no effect on the hydraulic pressure actually involved in the engagement of the clutch. Therefore, even if the torque converter internal pressure fluctuates due to a change in engine rotation, the lockup initial hydraulic pressure at the time when the filling is completed is always constant. Further, according to the present invention, since a large flow rate of oil can be supplied to the lockup clutch during the filling period by the flow rate control valve, the filling period can be greatly shortened. Further, the filling detection means can accurately grasp the end time of the filling, and can accurately recognize the start time point of the gradually increasing hydraulic pressure.

[Embodiment] FIG. 1 shows an embodiment of the present invention.

In the system of this embodiment, instead of the lockup modulation valve 14 and the solenoid valve 15 of the system shown in FIG. 4, an electronic pressure control valve 20 and a flow rate detection valve 30 are used.
The flow rate detection valve 30 is provided with a filling detection sensor 40. Note that other components are denoted by the same reference numerals as those in FIG. 4, and redundant description will be omitted.

This electronic pressure control valve 20 is a proportional control valve that operates according to an electric command output from the controller 50, and in order to prevent fluctuations in the lockup initial hydraulic pressure Ps due to fluctuations in the internal pressure of the torque converter 2, a torque converter 29 is used to prevent fluctuations. The internal pressure is fed back to the proportional solenoid 22 side of the pressure control valve 20.

The flow rate detection valve 30 is provided in order to flow a large flow rate of oil to the lockup clutch 1 at the time of filling to shorten the filling time. The flow rate detection valve 30 is filled based on the movement of the spool of the valve. A filling detection sensor 40 for detecting the end is provided.

FIG. 2 shows an example of the internal configuration of the pressure control valve 20, the flow rate detection valve 30, and the filling detection sensor 40 according to the present invention.

In the configuration shown in FIG. 2, the oil from the pump 5 flows in via the input port 60, and the oil is supplied to the lockup clutch 1 via the output port 61. Port 62 is blocked.

The electronic pressure control valve 20 has a spool 21, and this spool
The right end of 21 is in contact with the plunger 23 of the proportional solenoid 22, and the left end is supported by a spring 24. The oil pressure in the oil passage 27 is piloted in the oil chamber 26 defined by the spool 21 and the piston 25. Further, the internal pressure of the torque converter is introduced into an oil chamber 28 on the proportional solenoid 22 side of the pressure control valve 20 via an oil passage 29.

The flow rate detection valve 30 has a spool 31, and an orifice 32 is formed on the output port 61 side of the spool 31. The left end surface of the spool 31 is supported by the spring 33, and the oil chamber 34
The oil pressure in front of the orifice 32 acts on the oil via the oil passage 35.

Further, an electromagnetic pickup 40 as a filling detection sensor is arranged on the right side of the flow rate detection valve 30 via a main body cover 63, and the movement of the spool 31 of the flow rate detection valve 30 is detected by this pickup 40 to determine the end of filling. To do. That is, since the induced voltage generated in the electromagnetic pickup 30 changes as the spool 21 approaches and separates, the movement of the spool 21 is detected by detecting this change.

In the structure shown in FIGS. 1 and 2, when the lockup clutch 1 is to be engaged, the controller
50 turns on solenoid 22 of electronic pressure control valve 20.
As a result, the spool 21 of the pressure control valve 20 moves to the left, and the oil from the pump 5 flows into the pressure control valve 20 via the input port 60 and the oil passage 64. The oil flowing into the pressure control valve 20 flows into the flow rate detection valve 30 via the oil passage 27 and the port 36,
It flows into the lockup clutch 1 via the orifice 32 formed in the spool 31 and the output port 61. Further, the oil that has entered the port 36 is guided to the oil chamber 34 through the oil passage 35 provided in the spool 31.

Then, a pressure difference (PA-PB) is generated before and after the orifice 32 by the orifice 32, and due to this pressure difference, the spool 31 moves to the left and the flow rate detection valve 30 is opened. As a result, input port 60
The pressure oil flowing into the lockup clutch 1 directly enters the port 36 and flows into the lockup clutch 1 via the orifice 32.
The inflow of oil into the clutch 1 through the flow rate detection valve 30 continues until the clutch pack is filled with oil.

As shown in FIG. 3, the clutch hydraulic pressure is almost zero during the filling period until the clutch pack is filled with oil, and rises to the initial pressure Pc when the filling is completed.

When the clutch pack is filled with oil, the filling ends and the oil no longer flows.
The differential pressure before and after is eliminated, and as a result, the spool 31 of the flow rate detection valve 30 moves to the right due to the restoring force of the spring 33, and the flow rate detection valve 30 is returned to the closed state.

That is, the spool 31 of the flow rate detection valve 30 returns to the position shown in FIG. 2 by the restoring force of the spring 33 when the clutch pack is filled with oil. This is an electromagnetic pickup 40
By detecting with, it is possible to accurately detect the end of the Philip.

The detection signal of the electromagnetic pickup 40 is input to the controller 50, and when the controller 50 detects the end of filling by this input signal, the current applied to the solenoid 22 is gradually increased thereafter to gradually increase the clutch hydraulic pressure. . In this gradual increase, by appropriately changing the gradual increase pattern of the drive current supplied from the controller 50, the clutch hydraulic pressure can be gradually increased with an arbitrary inclination.

Here, the pressure receiving area at both ends of the spool 21 of the pressure control valve 20 is A (the same area), the initial clutch pressure is Pc, and the torque converter internal pressure is P.
Let t be the thrust of proportional solenoid 22 and solenoid 2
Since the torque converter internal pressure Pt is introduced to the oil chamber 28 on the second side,
The equilibrium relationship shown in the following formula is established.

F + A · Pt = A · Pc (1) Although the spring 24 acts to urge the spool 21 to the left, a spring having a small spring constant is used. Ignores the effect of.

By transforming equation (1) The lockup initial hydraulic pressure Ps obtained by subtracting the torque converter internal pressure Pt acting on the piston back pressure portion of the lockup clutch 1 from the clutch initial pressure Pc is Then, the torque converter internal pressure Pt is offset.

Now, the engine speed changes and the torque converter internal pressure changes from Pt to P
Suppose it has changed to t ′. The initial clutch pressure at this time is P
c ′, if the lockup initial hydraulic pressure is Ps ′, then the following equation holds, Ps ′ = Pc′−Pt ′ (5) From the above equations (4) and (5) Becomes Here, F = kI (k; proportional constant I; solenoid drive current), and if the proportional solenoid drive current I at the end of filling is always constant, F = constant,
Therefore, Ps = Ps '(7) is established from the equations (3) and (6), and the lockup initial hydraulic pressure Ps is always unchanged even if the internal pressure of the torque converter changes from Pt to Pt'.

In the above description, only the initial hydraulic pressure Ps at the time when the filling is completed is described, but the relational expression similar to the above is also established for the lockup hydraulic pressure Pr (FIG. 3) at the time of gradually increasing the hydraulic pressure thereafter, and this lockup The hydraulic pressure Pr is also not affected by the fluctuation of the torque converter internal pressure Pt.

That is, in this embodiment, by feeding back the torque converter internal pressure Pt to the oil chamber 28 on the solenoid side of the electronic pressure control valve 20, the torque converter internal pressure acting on the piston back pressure portion of the lockup clutch is offset, and the torque converter internal pressure is reduced. The fluctuation of the lockup initial hydraulic pressure Ps due to the fluctuation of is suppressed. Further, since the solenoid drive current I is set to be constant at the time of completion of filling, the lockup initial hydraulic pressure Ps can always take a constant value. Further, in this embodiment, during the filling period, the flow control valve 30
As a result, a large amount of oil can be supplied to the lockup clutch, so that the filling period tf can be greatly shortened. Further, since the electromagnetic pickup 40 detects that the spool 31 of the flow control valve 30 is changed from the open state to the closed state and outputs the filling end signal when the closed state is detected, it is possible to accurately grasp the end time of the filling. Therefore, it is possible to accurately recognize the start point of the hydraulic pressure increase. Further, in this embodiment, the internal pressure of the torque converter is canceled by the feedback control of the internal pressure of the torque converter, and a large amount of oil is supplied by the flow control valve during the filling period to shorten the filling period. The clutch pressure at 1, that is, the clutch initial pressure may be reduced to a value close to the internal pressure of the torque converter, whereby the shock at the time of clutch engagement due to the initial pressure can be reduced.

By the way, in the above-mentioned embodiment, the electromagnetic pickup 40 detects the movement of the spool of the flow rate detection valve 30 to determine the end of filling, but the filling detection means is the end of filling based on the movement of the spool of the flow rate detection valve 30. Any other configuration may be adopted as long as it can detect. For example, a piston is provided on the left side of the spool 31, the piston is supported by a spring 33, and the main body cover of the piston is accompanied by the movement of the spool 31.
The end of filling may be detected by electrically detecting the contact and separation with respect to 65.

[Advantages of the Invention] As described above, according to the present invention: 1) Since the internal pressure of the torque converter is fed back to the pressure control valve, the initial lock-up pressure changes even if the internal pressure of the torque converter changes due to changes in the engine speed. Without it, it can solve the problem that the clutch does not fill or the engagement point shifts. 2) Since the electronic pressure control valve is used, the lockup hydraulic pressure after completion of filling can be gradually increased 3) Flow rate Since a large amount of oil can be supplied to the lockup clutch by the detection valve, the filling time can be shortened. 4) The filling detection sensor detects that the spool of the flow control valve has changed from open to closed, and when the closed state is detected, filling is performed. Since the end signal is output,
It is possible to accurately grasp the end time of filling, and to accurately recognize the start time point of the gradually increasing hydraulic pressure.

5) The internal torque of the torque converter is canceled by the feedback control of the internal pressure of the torque converter, and a large amount of oil is supplied by the flow control valve during the filling period to shorten the filling period, so the initial clutch pressure is close to the internal pressure of the torque converter. It is also possible to lower the pressure, so that the shock at the time of clutch engagement due to the initial pressure can be reduced.

And so on.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention, FIG. 2 is a sectional view showing an internal configuration example of an electronic pressure control valve in this embodiment, and FIG. 3 is a clutch hydraulic pressure characteristic in the apparatus of the same embodiment. FIG. 4 is a hydraulic circuit diagram illustrating a conventional device, and FIG. 5 is a time chart showing clutch hydraulic pressure characteristics of the conventional device. 1 ... Lockup clutch, 2 ... Torque converter, 3 ... Transmission tank, 4 ... Strainer, 5 ... Hydraulic pump, 6,7,11,12 ... Relief valve, 8 ... Rear brake cooling, 9 ...... Oil cooler, 10 ...... Oil filter, 14 ...... Lockup modulation valve, 15 ...... Solenoid valve, 20 ...... Electronic pressure control valve, 22 ...... Proportional solenoid, 30 ...... Flow rate detection valve, 32 ...... Orifice , 40 …… Filling detection sensor,
50 …… Controller.

Claims (1)

[Claims] Claims: 1. A lockup clutch, in which an internal pressure of a torque converter is applied to a piston back pressure portion and engagement drive is performed in accordance with the supplied hydraulic pressure, and a lock for controlling the hydraulic pressure supplied to the lockup clutch. In an up-clutch hydraulic control device, a first input port leading to a hydraulic pump, an output port leading to the lock-up clutch, an orifice formed between the first input port and the output port, and an orifice in front of this orifice. A spool having a second input port located therein, and when a differential pressure is not generated across the orifice, the spool is closed by the force of a spring provided at one end of the spool to close the second input port. It communicates with the output port via the orifice, and opens when the differential pressure is generated to open the first and second inlets. A spool having a flow control valve that communicates a force port with the output port through the orifice, a valve inlet that communicates with a hydraulic pump, and a valve outlet that communicates with a second input port of the flow control valve. A pressure control valve that applies a hydraulic pressure in front of the orifice of the flow control valve to one pressure receiving surface of the spool and presses the other pressure receiving surface of the spool by an actuator that generates thrust corresponding to an electric command; A filling end detection means for detecting that the spool of the valve is changed from the open state to the closed state and outputting a filling end signal when detecting the closed state, and a predetermined actuator for the pressure control valve when the lockup clutch is engaged. Lockup clutch of the pressure control valve is communicated with the valve outlet by giving an electric command corresponding to the initial hydraulic pressure And a control means for giving an electric command to the actuator to sequentially increase the thrust of the actuator when a filling end signal is output from the filling end detection means, and an actuator side of the spool of the pressure control valve. A lockup clutch hydraulic control device characterized in that an internal pressure of the torque converter is applied to a pressure receiving surface.