JPH0517429B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a line pressure control device that generates line pressure for shift control of an automatic transmission from pump discharge pressure, and in particular, a line pressure control device that generates line pressure for shift control of an automatic transmission from pump discharge pressure. The present invention relates to a line pressure control device that includes a solenoid valve and a modifier valve that variably control pressure.

Conventional technology In general, line pressure control devices for automatic transmissions use a regulator valve to regulate the working fluid pressure discharged from an engine-driven hydraulic pump, thereby creating line pressure according to vehicle operating conditions. It's starting to become easier. The biasing force of a spring is generally used as the control element of the regulator valve, but a modifier valve is also provided to modify the line pressure according to the operating condition, and the signal pressure generated by the modifier valve is By introducing this into the regulator valve, more precise line pressure control is now possible. For example, such a line pressure control device has already been filed as Japanese Patent Application No. 59-251168 proposed by the applicant of the present application. That is, as shown in FIG. 2, this line pressure control device 1 is provided with a spring 2b at the lower end of the regulator valve 2 that presses the spool 2a upward, and at the lower end of the spool 2a. A signal pressure from the modifier valve 3 is applied to the vehicle, and by controlling this signal pressure according to the vehicle driving condition,
The regulator valve 2 regulates the discharge pressure from the pump 4 so as to balance it with the biasing force of the spring 2b and the signal pressure, thereby creating line pressure in the circuit 5. Further, the signal pressure from the modifier valve 3 is generated using the line pressure introduced via the circuit 5 as the source pressure.

A control pressure whose duty is controlled by a solenoid valve 6 acts on the modifier valve 3 via a circuit 7, and the signal pressure is controlled by a spool that moves in response to this control pressure. This allows the line pressure to be controlled more precisely. In addition, the solenoid valve 6
is provided to regulate the working oil pressure of friction elements such as clutches and band brakes, and the solenoid valve 6 is used to control the duty of the pilot pressure after the line pressure is reduced to a constant pressure by the pressure reducing valve 8. This duty-controlled control pressure is also used for the modifier valve 3.

Problems to be Solved by the Invention In the conventional line pressure control device 1, the line pressure from the circuit 5 is directly used as the source pressure of the signal pressure produced by the modifier valve 3, as described above. ing. However, this line pressure is the regulated discharge pressure from the pump 4,
Since there is large pulsation in this pump discharge pressure, the pulsation element inevitably remains in the line pressure. Therefore, even though the pilot pressure whose pulsation has been removed by the pressure reducing valve 8 is used as the source pressure of the control pressure, by directly using the line pressure as the source pressure of the signal pressure, the signal pressure is always A pulsating component appears.

Since the regulator valve is operated with the signal pressure in which this pulsation component exists, there is a problem in that the pulsation in the line pressure is further amplified.

Therefore, the present invention provides the source pressure for the signal pressure of the modifier valve and the source pressure for the control pressure of the solenoid valve.
It is an object of the present invention to provide a line pressure control device for an automatic transmission that suppresses the pulsation amplification effect and enables more precise line pressure control by using pilot pressure from which pulsations are removed by a pressure reducing valve.

Means for Solving the Problems In order to achieve the above object, the line pressure control device of the present invention operates by a control signal output from a controller and uses an electromagnetic system that generates a control pressure according to the operating state from the source pressure. a modifier valve having a spool operated by the control pressure and generating a signal pressure for line pressure control from the source pressure according to the spool position; and the signal pressure acting on the spool. and a regulator valve which has a spring that biases the spool and that adjusts the pump discharge force to balance the spring force and the signal pressure to generate line pressure. In a line pressure control device for an automatic transmission, a pressure reducing valve is provided to reduce the line pressure, and a pilot pressure output from the pressure reducing valve is used as the source pressure of the solenoid valve and the source pressure of the modifier valve. It is characterized by being guided by each.

Operation With the above-described configuration, the line pressure control device of the present invention reduces the line pressure using the pressure reducing valve to eliminate pulsating components as the source pressure of the signal pressure output from the modifier valve to the regulator valve. The removed pilot pressure is used. Since the pilot pressure from the pressure reducing valve is also used as the source pressure for the control pressure acting on the modifier valve, pulsation is eliminated. Therefore, the signal pressure generated by the modifier valve is free of pulsating components. Therefore, the pulsation does not affect the hydraulic pressure control of the regulator valve based on the signal pressure, and amplification of the pulsation component of the line pressure itself is prevented.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

That is, FIG. 1 shows a main part of a line pressure control device 10 for an automatic transmission showing one embodiment of the present invention, and 11
1 is a regulator valve, 12 is a modifier valve, and 13 is a solenoid valve. The regulator valve 11 has a spool 11b that is urged to the left half position in the figure by a spring 11a, and the discharge pressure from the hydraulic pump 14 is introduced into the port 11c via the circuit 15. It is also introduced into the port 11d via an orifice-equipped circuit 15a branched from the circuit 15, and acts as a load that presses the spool 11b downward. In the figure, 11e and 11f are drain ports, 11g is an atmosphere opening port, and 11h is a port for supplying hydraulic fluid to a torque converter (not shown) through a circuit 16. And, at the lower end of the regulator valve 11,
The signal pressure from the modifier valve 12 acts through the signal pressure supply circuit 17, and the upward pushing force of the signal pressure of the spring 11a acts as follows.
The spool 11b moves to a position that balances the downward pressing force due to the hydraulic pressure applied to the port 11d, and as the spool 11b moves downward from the right half position in the figure, the port 11c communicates with the drain port 11e and opens inside the port 11c. The hydraulic pressure is regulated and supplied to the circuit 15 as line pressure.

On the other hand, the modifier valve 12 has a spool 12b that is biased toward the right half position in the figure by a spring 12a, and the upper end of the spool 12b is connected to the electromagnetic valve 13 via a control pressure supply circuit 18.
At the same time, a signal pressure is applied to the lower end of the spool 12b via an orifice-equipped circuit 17a branching from the signal pressure supply circuit 17. And the spring 12
The spool 12b moves to a position where the downward pressing force caused by the cooperation of the control pressure and the control pressure and the upward pushing force caused by the signal pressure are balanced, and the port 12c communicating with the source pressure circuit 19 and the signal Pressure supply circuit 1
The signal pressure is controlled by changing the amount of restriction between the port 12d and the port 7 communicated with the port 12d. Reference numeral 12e denotes a drain port, which is configured to cut off the source pressure circuit 19 and remove residual signal pressure in the signal pressure supply circuit 17 from the drain port 12e when the spool 12b moves further upward from the left half position in the figure. It's summery.

The solenoid valve 13 is provided in a drain circuit 18a branching from the control pressure supply circuit 18,
A plunger 13a that opens and closes the circuit 18a is urged in the valve opening direction by a spring 13b.
When the solenoid 13c is energized, the solenoid valve 13 is opened to drain the hydraulic pressure in the circuit 18, and when the solenoid 13c is deenergized, it is opened to close the drain circuit 18a. It's summery. The duty ratio of the drive pulse signal outputted from a microcomputer (not shown) is variably controlled based on the vehicle operating condition, so that the control pressure is adjusted to the control pressure supply circuit 18 according to the vehicle operating condition.
It is now generated internally. The control pressure supply circuit 18 is connected to the source pressure circuit 19 via an orifice 20, and hydraulic pressure is supplied from the source pressure circuit 19 to the control pressure supply circuit 18.

Here, in this embodiment, the source pressure circuit 19
A pressure reducing valve 30 is provided between the line pressure circuit 15 and the line pressure circuit 15 to reduce the line pressure to a constant pressure. That is, the pressure reducing valve 30 has a spool 30b that is urged to the upper half position in the figure by a spring 30a, and the port 3
The line pressure circuit 15 is connected to the port 0c, and the source pressure circuit 19 is connected to the port 30d. Furthermore, a pilot pressure circuit 31 with an orifice branched from the source pressure circuit 19 connects to the pressure reducing valve 3.
0 communicates with the rightmost chamber 30e. Therefore, the spool 30b is moved to a position where the rightward pushing force by the spring 30a and the leftward pushing force by the pilot pressure acting on the chamber 30e are balanced, and the line pressure in the port and 30c is throttled by the spool 30b. After the pressure is reduced to a constant pressure, the port 30
d to the source pressure circuit 19 and the pilot pressure circuit 31
It is becoming increasingly supplied to Here, the pulsation of the line pressure is caused by the pilot pressure generated in the port 30d being led to the chamber 30e and moving the spool 30b, which acts to cancel pressure fluctuations.
Does not affect pilot pressure. In other words, pressure reducing valve 3
Along with the pressure reduction effect of 0, the pulsating component of the line pressure is reliably removed.

The operation of the line pressure control device 10 of this embodiment with the above configuration will be described below.

The line pressure supplied to the pressure reducing valve 30 via the line pressure circuit 15 has its pulsations removed by the pressure reducing valve 30 and is output to the source pressure circuit 19 as a constant pressure pilot. The pilot pressure introduced into the control pressure supply circuit 18 side becomes the source pressure of the solenoid valve 13,
Duty control of the electromagnetic valve 13 generates a control pressure depending on the vehicle operating state. As a result, a control pressure without pulsation is output to the modifier valve 12. Then, the modifier valve 1
2, the spool 12b operates according to the control pressure, and generates a signal pressure using the pilot pressure from the source pressure circuit 19 as the source pressure. Since this signal pressure is based on the pilot pressure from which pulsation has been removed as described above, the signal pressure is a hydraulic pressure from which pulsation has been removed. The signal pressure output from the modifier valve 12 in this way is supplied to the regulator valve 11 via the signal pressure supply circuit 17, and the spool 1 of the regulator valve 11 is
1b. At this time, since there is no pulsation component in the signal pressure, the control of the regulator valve 11 is not affected by the pulsation. Therefore, the line pressure discharged from the port 11c is not affected by the pulsation from the regulator valve 11. In other words, the pulsation of the line pressure itself causes the solenoid valve 1
3. It is not further amplified by the system consisting of the modifier valve 12 and the regulator valve 11.

In this embodiment, the modifier valve 12 and the solenoid valve 13 have a common source pressure circuit 19 that supplies source pressure, and a single pressure reducing valve 30 supplies a common source pressure circuit 19 to the modifier valve 12 and the solenoid valve 13. Although the example shown above is designed to supply pilot pressure, the present invention is not limited to this, and it is possible to provide separate source pressure circuits for the modifier valve 12 and the solenoid valve 13, and to provide dedicated pressure reducing circuits for each of these source pressure circuits. A valve may be provided to supply different pilot pressures to the modifier valve 12 and the solenoid valve 13.

In addition, although the solenoid valve 13 is shown as being duty-controlled to create the control pressure, it is also possible to create the control pressure by controlling the excitation force of the solenoid in an analog manner and adjusting the amount of restriction by the plunger. It is also possible to use

Effects of the Invention As explained above, in the line pressure control device for an automatic transmission of the present invention, pulsation is suppressed by the pressure reducing valve as the source pressure of the signal pressure of the modifier valve and the source pressure of the control pressure of the solenoid valve. Since the removed pilot pressure is used, there is no pulsation component in both the control pressure that controls the modifier valve and the source pressure introduced into the modifier valve. Therefore, no pulsating component occurs in the signal pressure output from the modifier valve. Therefore, the hydraulic pressure control of the regulator valve by this signal pressure is not affected by pulsation, and the pulsation of the line pressure itself is further suppressed by the system consisting of the solenoid valve, modifier valve, and regulator valve. This can prevent the phenomenon that occurs when it is amplified. Therefore, more stable line pressure can be supplied.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts showing an embodiment of the line pressure control device of the present invention, and FIG. 2 is a block diagram of main parts showing a conventional line pressure control device. 10...Line pressure control device, 11...Regulator valve, 12...Modifier valve,
13... Solenoid valve, 14... Hydraulic pump, 17...
Signal pressure supply circuit, 18... Control pressure supply circuit, 30
……Pressure reducing valve.

Claims (1)

[Scope of Claims] 1. A solenoid valve that is activated by a control signal output from a controller and generates a control pressure according to the operating state from the source pressure, and a spool that is activated by the control pressure,
It has a modifier valve that generates a signal pressure for line pressure control from the source pressure according to the spool position, and a spring that introduces the signal pressure so as to act on the spool and biases the spool. , a regulator valve that adjusts pump discharge pressure to balance with the spring force and the signal pressure to generate line pressure; and a line pressure control device for an automatic transmission, which reduces the line pressure. A line pressure control device for an automatic transmission, characterized in that a pressure reducing valve is provided, and the pilot pressure output from the pressure reducing valve is guided as the source pressure of the solenoid valve and the source pressure of the modifier valve, respectively. .