JPS584225B2 - How to make a difference in your life - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic control device for an automatic transmission for a vehicle, and more specifically to a hydraulic control device for a hydraulic control device provided in the hydraulic control device to alleviate shift shock during gear shifting. This relates to a hydraulic pressure supply structure for back pressure to an accumulator.

Automatic transmissions for vehicles combine a hydraulic torque converter with a gear transmission mechanism as an auxiliary transmission, and the required gear shift engagement of the gear transmission mechanism is achieved by a coupling device such as a clutch or brake operated by a hydraulic control device. Many structures have been adopted.

In such automatic transmissions for vehicles, in order to reduce the shock when the clutch or brake is engaged when shifting to each range, so-called shift shock,
A buffer accumulator is installed in the oil supply path to the clutch or brake, thereby alleviating the sudden rise in the oil pressure supplied to the clutch or brake during gear shifting, and allowing the oil pressure to rise gradually. The clutch and brake are not activated suddenly.

It is preferable that the buffering properties of the accumulator's action or the hardness of its action to soften such shift shock be adjusted in accordance with the engine torque so that the hardness increases as the engine torque increases.

For this reason, conventionally, throttle oil pressure, line oil pressure, and various other regulated oil pressures are applied as back pressure to the accumulator, thereby controlling the hardness of the buffering action of the accumulator.

The back pressure characteristics of the accumulator controlled in this manner generally increase monotonically in accordance with the engine torque, or maintain a constant pressure above a certain throttle opening, or slightly change the pressure increase gradient.

Some diesel engines and some gasoline engines exhibit a bending characteristic in which the engine torque decreases above a certain throttle opening depending on the shift point and engine characteristics.

In an engine exhibiting such characteristics, if the back pressure control to the shift shock buffer accumulator in the hydraulic control device of the automatic transmission is performed in the conventional manner described above, the throttle opening at which the engine torque begins to decrease will be reduced. In the above case, the degree of hardness of the buffering action of the accumulator does not match the engine torque characteristics, and it is not possible to appropriately alleviate the shift shock over the entire operating range of the engine.

The present invention has been made in view of the above-mentioned problems in the conventional control of back pressure to the shift shock buffer accumulator. By gradually decreasing the oil pressure as the engine torque decreases,
It is an object of the present invention to provide a hydraulic control device for a hydraulic transmission of an automatic transmission that can appropriately adjust shift shock mitigation over the entire operating range of an engine.

According to the present invention, this object is achieved by: a throttle oil pressure control valve that generates a throttle oil pressure according to a throttle opening degree;
an accumulator that is provided in an oil passage that supplies hydraulic pressure to a coupling device that achieves gear shift meshing of the transmission and provides a buffering effect to the coupling device; and an accumulator that regulates the throttle hydraulic pressure to a predetermined characteristic and uses the regulated hydraulic pressure. a back pressure control valve that supplies back pressure to the accumulator, and the back pressure control valve is biased in the valve opening direction by a spring and is driven by a combined force of the throttle oil pressure and the output oil pressure from the back pressure control valve. It includes a valve body that is biased in the valve closing direction, and outputs a hydraulic pressure equal to the throttle hydraulic pressure up to a predetermined throttle opening, and gradually decreases as the throttle opening increases beyond the predetermined throttle opening. This is achieved by a hydraulic control device of an automatic transmission, such as one configured to output hydraulic pressure such as that shown in FIG.

The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

The attached FIG. 1 is a hydraulic control circuit diagram in which the accumulator back pressure control mechanism of the present invention is incorporated into a general hydraulic control system for an automatic transmission.

In the figure, 1 is an oil pump, and the hydraulic pressure generated by the pump is supplied to a line hydraulic pressure control valve 3 via an oil path 2.

Although the detailed valve structure is omitted in the figure, the line oil pressure control valve 3 is constituted by a well-known oil pressure control valve element commonly used in the past, and regulates the maximum oil pressure generated by the oil pump 1. The system automatically adjusts the hydraulic pressure sent to each part to match the vehicle speed and engine torque at that time.

This adjusted oil pressure, ie, line oil pressure, is supplied to the oil pressure intake port 6 of the throttle oil pressure control valve 5 via an oil line 4.

The throttle oil pressure control valve 5 includes a first valve body 9 held in equilibrium between two upper and lower compression coil springs 7 and 8, and a second valve body abutting the upper end of the upper compression coil spring 7. 10, and a pressing force is applied to the upper end of the second valve body 10 downward in the figure in accordance with the opening degree of the throttle valve of the carburetor or the degree of depression of the accelerator pedal.

In such a throttle oil pressure control valve 5, the second valve body 10 is pushed downward as the throttle valve opens,
By increasing the spring force of the compression coil springs 7 and 8 according to the throttle opening, this spring force and the first valve body 9
Due to the force balance relationship with the return hydraulic pressure from the throttle hydraulic control valve introduced between lands 9a and 9b, a linear hydraulic pressure proportional to the throttle opening is applied to the hydraulic pressure take-out port 11 of the control valve 5, that is, the throttle It's getting hydraulic pressure.

The throttle oil pressure from the oil pressure take-out port 11 is sent via an oil passage 12 to various parts (not shown) of the hydraulic control device in a predetermined manner.

Reference numeral 13 denotes a shift shock buffering accumulator rake provided in an oil supply passage 15 to an engagement device 14 such as a clutch for achieving gear change engagement of a transmission (not shown), and the accumulator 13 has one end connected to the oil supply passage 15. A cylinder chamber 17 in which a communicating port 16 is opened, and the cylinder chamber 17
A piston 19 is slidably fitted inside and is always urged toward the port 16 by a compression coil spring 18, and a piston 19 opens at the other end of the cylinder chamber and acts as back pressure for the accumulator in the cylinder chamber. and a back pressure intake port 20 for supplying hydraulic pressure.

In this accumulator 13, the piston 19 receives the line oil pressure of the oil supply passage 15 from the port 16, and as a result, the piston 19 is connected to the compression coil spring 18 and the cylinder chamber 1.
By overcoming the back pressure supplied in the oil supply line 7 and rising, it absorbs the shocking rise of the line oil pressure in the oil supply passage 15 and alleviates the shift shock when the coupling device 14 is engaged. It looks like this.

The back pressure intake port 20 of the accumulator 13 is supplied with hydraulic pressure regulated to have a predetermined characteristic that follows the engine torque by a back pressure control valve 21.

The back pressure control valve 21 is connected to an oil intake port 22 to which the throttle oil pressure from the throttle oil pressure control valve 5 is supplied via an oil passage 12', and to the back pressure intake port 20 of the accumulator 13 via an oil passage 23. The valve body 25 is arranged in such a manner that the opening degree of the port 24 is increased or decreased by a compression coil spring 26. The valve is biased in the direction in which the valve opens, that is, in the direction in which the valve opens.

A part of the throttle hydraulic pressure supplied to the hydraulic pressure intake port 22 is introduced between the lands 25a and 25b having different pressure receiving areas through the pilot oil passage 27, and is introduced into the lands 25a and 25b having different pressure receiving areas.
The valve body 25 acts to urge the valve body 25 in the valve closing direction against the pressure.

Also, a return oil passage 28 is provided on the lower surface of the lower end land 25c of the valve body 25.
Output hydraulic pressure is introduced from the hydraulic pressure take-out port 24 through the hydraulic pressure output port 24, and the combined force of this hydraulic pressure and the throttle hydraulic pressure from the pilot oil passage 27 biases the valve body 25 in the valve closing direction.

Therefore, when the throttle oil pressure from the throttle oil pressure control valve 5 is low and the combined force of this oil pressure and the output oil pressure introduced into the return oil path 28 is lower than the spring force of the compression coil spring 26, the valve body 25 Hydraulic outlet port 2 as shown
4 is in the most open state, and therefore a hydraulic pressure equal to the throttle hydraulic pressure taken into the back pressure control valve 21 is extracted from the hydraulic pressure extraction port 24, and this is supplied to the accumulator 18 as back pressure.

When the throttle oil pressure increases and the above-mentioned resultant force overcomes the spring load of the compression coil spring 26, the valve body 25
is moved upward in the figure in order to reduce the opening degree of the oil pressure take-out port 24, and in this state, the oil pressure taken out to the oil pressure take-out port 24 becomes the oil pressure determined by the following equation.

PBP=(F0-ΔS・PTh)/(S1)(1)PB
P: Output oil pressure (back pressure applied to the accumulator), P
Th: Throttle oil pressure, S1: Lower end land 25c of valve body
pressure receiving area, ΔS: difference area between the lands 25a and 25b of the valve body, F0: spring load of the spring 26, that is, the throttle oil pressure increases, and after the resultant force overcomes the spring load, the throttle oil pressure becomes higher. Accordingly, the output oil pressure from the back pressure control valve 21 gradually decreases.

Figure 2 shows the characteristics of the back pressure control valve depending on the throttle opening, where the solid line is the output oil pressure of the back pressure control valve, the broken line is the virtual extension of the oil pressure determined by the above formula (1), and the dashed line is the It shows a virtual extension of the throttle oil pressure. For example, if the turning point is designed at 50% throttle opening, the output oil pressure of the back pressure control valve is equal to the throttle oil pressure below that point, and is 50%.
% or more, the characteristics become equal to the oil pressure determined by the above formula (1).

Note that the switching point between the throttle oil pressure and the oil pressure determined by the above formula, that is, the bending point and the oil pressure gradient, can be arbitrarily changed by appropriately changing the spring force of the compression coil spring, the difference in area of the land portion of the valve body, etc. Needless to say, it can be determined and obtained.

Figure 3 shows the engine torque and the operating range of the accumulator (torque capacity change in the coupling device) corresponding to the throttle opening, and the output oil pressure with the required characteristics can be obtained by using the back pressure control valve as described above. Thus, it will be understood that the accumulator operates properly within the torque range in which it is supposed to absorb impact torque, and ensures shock mitigation during gear changes over the entire operating range of the engine.

Although the present invention has been described above in detail with reference to specific embodiments, it is understood that the present invention is not limited to such embodiments and that various modifications can be made within the scope of the present invention. This will be obvious to businesses.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic control circuit diagram in which the present invention is incorporated into a hydraulic control system for an automatic transmission having a general structure, and Fig. 2 shows the back pressure to the accumulator achieved in the hydraulic control system shown in Fig. 1. FIG. 3 is a graph showing oil pressure versus throttle opening, and FIG. 3 is a graph showing engine torque corresponding to throttle opening and the operating range of the accumulator achieved in the hydraulic control system shown in FIG. 1...Oil pump, 2...Oil path, 3
... Line oil pressure control valve, 4 ... Oil path,
5... Throttle hydraulic control valve, 6...
Hydraulic intake port, 7, 8... Compression coil spring, 9... First valve body, 10... Second valve body, 12... Oil passage, 13... Accumulator for chute shock buffer, 14... Coupling device, 15... Oil supply path, 16... Port, 17... ...Cylinder chamber, 18...
Compression coil spring, 19...Piston, 20...
...Back pressure intake port, 21...Back pressure control valve, 22...Hydraulic pressure intake port, 23...
...Oil passage, 24...Hydraulic pressure outlet port, 25.
... Valve body, 26 ... Compression coil spring, 2
7...Pilot oil path, 28...Return oil path.

Claims (1)

[Claims] 1. A throttle hydraulic pressure control valve that generates throttle hydraulic pressure according to the throttle opening degree, and an accumulator that is provided in an oil passage that supplies hydraulic pressure to a coupling device that achieves gear shift meshing of the transmission and that provides a buffering effect to the coupling device. and a back pressure control valve that regulates the throttle oil pressure to a predetermined characteristic and supplies the regulated oil pressure to the accumulator as back pressure, the back pressure control valve being biased in the valve opening direction by a spring, and It includes a valve body that is biased in the valve closing direction by the combined force of the throttle oil pressure and the output oil pressure from the back pressure control valve, and outputs oil pressure equal to the throttle oil pressure until a predetermined throttle opening, and 1. A hydraulic control device for an automatic transmission, characterized in that the hydraulic pressure control device for an automatic transmission is configured to output a hydraulic pressure that gradually decreases as the throttle opening increases when the throttle opening is exceeded.