JPH0532615B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention provides a hydraulically operated transmission for a vehicle.
An accumulator is provided to prevent the hydraulic pressure of a hydraulic clutch and other hydraulic engagement elements that establish a predetermined drive train in a transmission from changing suddenly due to oil supply and drainage during gear shifting, that is, to provide a buffering effect against pressure changes. The present invention relates to a back pressure control device.

(Prior art) Conventionally, the hydraulic pressure input to the back pressure chamber of the accumulator is changed according to the throttle opening of the engine.
It is possible to reduce the shift shock by changing the hydraulic range in which the buffering effect of the accumulator can be obtained in response to the change in the actual engagement hydraulic pressure of the hydraulic engagement element based on the change in engine torque according to the throttle opening degree. It is being done.

As a back pressure control device for this purpose, the applicant of the present application previously disclosed in Japanese Patent Application No. 166309/1982 that the back pressure chamber of the accumulator is connected to a hydraulic power source via an oil path connected to the back pressure chamber, and that an electromagnetic type The atmosphere release valve is connected and the opening/closing of the air release valve is controlled via the control circuit using the signal from the opening detector that detects the throttle opening, and the air release valve is opened in the low throttle opening range. We proposed a valve that cuts off the input of hydraulic pressure from the hydraulic source to the back pressure chamber and reduces the back pressure of the accumulator.

(Problem to be Solved by the Invention) In the above-mentioned proposal, the control circuit is generally configured to control the opening and closing of the atmospheric release valve at all times according to the signal from the opening detector, so that the speed change is difficult. Even when the accumulator does not need to operate after completion, if the throttle opens at a low opening, the atmosphere release valve will open, causing an unnecessary leak of pressure oil from the hydraulic circuit. There is a problem that requires a larger source.

It is an object of the present invention to provide an improved device of the above proposal which solves these problems.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a control circuit for controlling the opening and closing of the atmosphere release valve so that the atmosphere release valve is controlled to open and close independently of the signal from the opening detector except during gear shifting. The valve was configured to hold the valve closed.

(Function) During gear shifting, the control circuit controls the opening and closing of the atmospheric release valve according to the signal from the opening detector, and the back pressure of the accumulator increases or decreases according to the throttle opening. Even if the opening becomes low, the atmosphere release valve will not open, and unnecessary leakage of pressure oil will not occur.

(Example) Embodiments of the present invention will be described based on the drawings.

Referring to FIG. 1, reference numeral 1 denotes a hydraulic clutch as a hydraulic engagement element, and the hydraulic clutch 1 is used in a hydraulically operated transmission constituting an auxiliary transmission connected to an engine via, for example, a fluid torque converter. Intervening in a predetermined drive train, a clutch oil passage 2 connected to the hydraulic clutch 1 is connected to an oil supply passage 5 connected to a hydraulic power source 3 via a regulator valve 4 via a shift valve 6. By switching, oil is supplied and drained from the hydraulic clutch 1 to establish and release the drive train, thereby changing gears between the drive train and other drive trains.

The shift valve 6 has a right oil supply position (the illustrated position) connecting the clutch oil passage 2 to the oil supply passage 5;
The clutch oil path 2 can be freely switched to the left oil drain position where it connects to the oil drain port 7, and the pilot oil path 8, which branches from the oil supply path 5 and connects to the oil chamber 6a at the left end of the valve 6, is provided with an electromagnetic air vent. When the valve 9 is connected and the release valve 9 is closed, the line pressure from the oil supply path 5 is input to the oil chamber 6a, and the valve 6 is switched to the oil supply position against the right end spring 6b. When the release valve 9 is opened, the input of line pressure to the oil chamber 6a is cut off, and the valve 6 is switched to the oil drain position by the spring 6b. An accumulator 10 is connected to the clutch oil passage 2 to buffer sudden changes in clutch pressure caused by oil supply and discharge to the hydraulic clutch 1, and a back pressure chamber 10b that applies back pressure to the piston 10a of the accumulator 10. is connected to the oil supply path 5 via an oil path 11, and an electromagnetic atmosphere release valve 12 is connected to the oil path 11.
When the release valve 12 is closed, the line pressure from the oil supply path 5 is input to the back pressure chamber 10b, and the back pressure of the accumulator 10 increases, creating a hydraulic region that provides a buffering effect against pressure changes. is modulated to the high pressure side, and when the release valve 12 is opened, the line pressure input to the back pressure chamber 10b is cut off, and the back pressure is reduced to a relatively small value due to only the spring 10c,
The hydraulic pressure region that produces the buffering effect is modulated to the low pressure side.

The opening and closing of the atmosphere release valve 12 and the atmosphere release valve 9 are controlled by a control circuit 13 comprising a microcomputer mounted on the vehicle.This will be explained with reference to FIG. Signals from a vehicle speed detector 14 and an opening detector 15 that detects the throttle opening of the engine are input to the control circuit 13, and the output from the control circuit 13 is sent to each open valve 9, via each amplifier 16, 17. 12 solenoid 9a, 1
The energization to 2a is controlled, and each of the open valves 9 and 12 is set to a normally closed type, for example, and each solenoid 9 is
The valve is opened by energizing a and 12a.

Here, the opening/closing control of the atmospheric release valve 9 by the control circuit 13 is performed in the same manner as in the case of a well-known electronically controlled automatic transmission.
determines the drive train to be established at the present time according to the signals from both detectors 14 and 15 based on the shift characteristics predetermined according to the vehicle speed and throttle opening, and issues an energization command to the solenoid 9a accordingly. It functions to output an energization stop command (hereinafter, these two commands are collectively referred to as a shift command).
Further, the control circuit 13 determines whether the throttle opening is greater than or equal to a predetermined value based on a signal from the opening detector 15, and outputs an energization command and an energization stop command to the solenoid 12a accordingly, and controls the atmosphere release valve. 12
In addition to functioning to open and close the open valve 12, in accordance with the characteristics of the present invention, when the gear is not changed, the energization stop command is continuously output regardless of the signal from the opening degree detector 15, and the open valve 12 is closed. Functions to hold the valve.

This will be explained in detail according to the flowchart shown in FIG. 3. First, in step _S1 , the control circuit 13 determines whether or not the hydraulic clutch 1 is supplied with oil or not, depending on whether or not the shift command has changed. When the shift command changes and oil is supplied and drained, that is, during gear shifting, it is determined in step _S2 whether the current throttle opening θ is greater than or equal to a predetermined value θ ₀ , and it is determined as ``YES''. If so, proceed to step S ₃ and output the energization stop command, close the atmospheric release valve 12 and increase the back pressure of the accumulator 10, and if the determination is "NO", proceed to step S ₄ and output the energization. Output the command and open the release valve 1
2 is opened to reduce the back pressure of the accumulator 10.

In the next step _S5 , select "YES" in step _S1 .
The measured time t from the time when it is determined is the predetermined time t ₀
It is determined whether or not the above period has elapsed, and when the determination is "NO", the process returns to step _S2 and the above-described determination processing operation is repeated. Here, the predetermined time t ₀ is set equal to the shift time from the start of oil supply/drainage to the hydraulic clutch 1 until the engagement and release of the clutch 1 is completed, and this is determined economically.

If it is determined to be ``YES'' in step _S5 , that is, when the gear shift is completed, t is reset to zero and _the program returns to step _S1 , where it continues until the next gear shift is performed. If the judgment is "NO", the process proceeds to step _S6 and outputs the energization stop command, and thereafter returns to step _S1 and proceeds to step _S6 , which is repeated until the atmosphere release valve 12 is closed regardless of the throttle opening The valve is kept closed.

Therefore, unnecessary leakage of pressure oil from the hydraulic circuit due to opening of the atmosphere release valve 2 during non-shifting does not occur.

Incidentally, in the above embodiment, the back pressure of the accumulator 10 during gear shifting is changed in two stages, high and low, with the predetermined opening degree θ ₀ of the throttle as a boundary, but as disclosed in the above-mentioned earlier application, the back pressure of the accumulator 10 is It is also possible to change the back pressure in multiple stages by configuring it to have multiple back pressure chambers and connecting an air release valve to the oil path leading to each back pressure chamber. Keep all atmospheric release valves closed.

Furthermore, the present invention is of course applicable to planetary gear type transmissions that use, for example, a hydraulic brake other than a hydraulic clutch as a hydraulic engagement element.

(Effects of the Invention) As described above, according to the present invention, the atmosphere release valve for controlling the back pressure of the accumulator does not open when the gear is not shifted and causes unnecessary leakage of pressure oil, and the hydraulic power source can be downsized. It has the effect of achieving

[Brief explanation of the drawing]

Figure 1 is a hydraulic circuit diagram of one example of the device of the present invention, Figure 2 is a hydraulic circuit diagram of an example of the device of the present invention;
The figure is a block circuit diagram of the control system of the atmosphere release valve,
The figure is a flowchart of the control circuit. 1... Hydraulic clutch (hydraulic engagement element), 3... Hydraulic source, 10... Accumulator, 10b... Back pressure chamber, 1
DESCRIPTION OF SYMBOLS 1... Oil path, 12... Atmospheric release valve, 13... Control circuit.

Claims (1)

[Scope of Claims] 1. An accumulator 10 is connected to an oil passage 2 connected to a hydraulic engagement element 1 for shifting provided in a transmission, and the hydraulic pressure input to a back pressure chamber 10b of the accumulator 10 is adjusted to the throttle opening of the engine. The back pressure control device is configured to change the back pressure according to the pressure in the back pressure chamber 10.
b is connected to the hydraulic pressure source 3 via an oil passage 11 connected to the back pressure chamber 10b, and an electromagnetic atmosphere release valve 12 is connected to the oil passage 11 connected to the back pressure chamber 10b. The opening/closing is controlled via the control circuit 13 by the signal from the opening detector 15 that detects the throttle opening, and when the control circuit 13 is not changing gears, the signal from the opening detector 15 is A back pressure control device for an accumulator in a hydraulically operated transmission for a vehicle, characterized in that the atmosphere release valve 12 is kept closed regardless of the condition.