JPS60260747A - Hydraulic control device of automatic speed change gear for car - Google Patents

Abstract

PURPOSE:To lessen a speed change shock by independently setting a value of oil pressure supplied to a back pressure chamber of a hydraulic accumulator and motion area for controlling oil pressure in a low load operation area separately from the other operation areas. CONSTITUTION:In a hydraulic control device of a geared speed change mechanism 1 where a speed change step is switched by the engagement and disengagement of a hydraulic frictional engagement device 2 such as a clutch, a brake or the like, pressure governed line oil pressure PL is selectively supplied to the frictional engagement device 2 from an oil path 5 through a line oil pressure control valve 3 and a speed change valve 4. A hydraulic accumulator 6 is connected to the oil path 5, and a back pressure chamber 16 is connected to an outlet port 22 of an accumulator control valve 20 by an oil path 18. The control valve 20 is controlled by a line oil pressure PL supplied to a control port 24 through a choke valve 30 when the line oil pressure PL does not amount to a designated value to supply fixed oil pressure to the back pressure chamber 16.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hydraulic control device for a transmission used in a vehicle such as an automobile, and in particular to a hydraulic accumulator incorporated in the hydraulic control device to reduce shift shock. Related to back pressure control device.

BACKGROUND OF THE INVENTION Automatic wheel transmissions used in vehicles such as automobiles include a gear transmission mechanism configured by a gear mechanism such as a planetary gear mechanism, and a hydraulically operated friction engagement device such as a clutch or brake. The automatic transmission is configured to switch the gear position of the gear change AM mechanism upon engagement and release of the frictional engagement device, and this automatic transmission is conventionally known in various configurations.
Further, hydraulic control devices having various configurations are known as control devices for automatic transmissions.

As one of the hydraulic control devices for the automatic transmission for vehicles as described above, a hydraulic pressure supply 11 is provided to the frictional engagement device in order to reduce shift shock caused by sudden engagement of the frictional engagement device. It is connected in the middle of the oil path to increase the hydraulic pressure of the frictional engagement device 3! A device having a hydraulic accumulator for controlling the pressure is already known, and this hydraulic control device is known, for example, in Japanese Patent Publication No. 56-2227, Japanese Patent Publication No. 5'l-3
No. 2253 and Japanese Patent Publication No. 57-32254.

The hydraulic comb mulator incorporated into the hydraulic control I device is
In general, a back pressure chamber is provided in order to change the hydraulic range in which the accumulator operates according to the output torque of the internal combustion engine that acts on the frictional engagement device in order to reduce shift shock, and the accelerator pedal is placed in the back pressure chamber. The hydraulic pressure range in which the accumulator operates is changed in response to changes in the line hydraulic pressure by being supplied with a hydraulic pressure called line hydraulic pressure that increases as the amount of depression increases.

If the line oil pressure, which is determined according to the amount of depression of the accelerator pedal, is the oil pressure that changes in accordance with the output torque of the internal combustion engine, which changes depending on the amount of depression of the accelerator pedal, the hydraulic accumulator will store the line oil pressure in its back pressure chamber. J: No matter how much the rear accelerator pedal is pressed,
a! The hydraulic pressure range in which the accumulator operates is appropriately changed according to the internal combustion engine's output torque that acts on the friction engagement device, effectively reducing shift shock at any time. As already mentioned in No. 55-39536, it is not compatible with the entire range of the amount of depression of the accelerator pedal, and for this reason, conventionally, hydraulic pressure: L-
The muleta works effectively to reduce shift shock only in a specific engine load range.

In view of the above-mentioned problems, an accumulator control valve is included, and the line hydraulic pressure is regulated to a hydraulic pressure that changes approximating the output torque characteristic with respect to the accelerator pedal depression amount of the internal combustion engine, and this hydraulic pressure is adjusted to the back of the hydraulic accumulator. A hydraulic control device configured to supply pressure to a pressure chamber has already been proposed in the above-mentioned Japanese Patent Application No. 55-39536.

In the previously proposed hydraulic control device as described above, the hydraulic accumulator control valve has a relationship that is substantially inversely proportional to the amount of accelerator pedal depression in a region where the amount of depression of the accelerator pedal is small, that is, in a low load driving range. Although this achieves the intended purpose, there is little freedom in changing the change characteristics of the oil pressure supplied to the back pressure chamber of the hydraulic accumulator, that is, the back pressure characteristics. Therefore, in this hydraulic control device, it is difficult to easily obtain the back pressure characteristics suitable for various internal combustion engines having different output torque characteristics, and there is a lack of flexibility in adapting the back pressure characteristics. That is, unless the land diameter of the valve element of the accumulator control valve is changed, it is not possible to change the rate of increase in the regulating oil pressure with respect to the increase in the amount of accelerator pedal depression. Even if the ratio of the output torque to the full-load output torque during low-load operation differs greatly between a carburetor type internal combustion engine and a fuel injection type internal combustion engine, back pressure characteristics suitable for both can be obtained. You can't do something like that easily.

Furthermore, the operating pressure of a hydraulic accumulator is increased as the exhaust capacity of the internal combustion engine increases, but the output torque of the internal combustion engine during idling does not change much depending on the exhaust capacity. The operating pressure during operation cannot be changed independently from that in other operating ranges, and for this reason, conventionally, when the operating pressure of the hydraulic accumulator is increased in accordance with the increase in the exhaust capacity of the internal combustion engine, Shift shock becomes worse when changing range from N range to R range or when power is turned off.

Purpose of the Invention In view of the above-mentioned problems in the conventional hydraulic control device, the present invention aims to improve the value of the hydraulic pressure supplied to the back pressure chamber of the hydraulic accumulator in the low load operating range and the operating range in which it is controlled. It is possible to set the tA4J independently for each other operating range, allowing a high degree of freedom in changing the back pressure characteristics of the hydraulic accumulator, and the back pressure characteristics are suitable for various internal combustion engines with different output torque characteristics. easily 1q
The purpose is to provide a hydraulic control device that can perform

According to the present invention, the above-mentioned object is to provide a gear transmission mechanism and a hydraulically operated friction engagement device, and to change the gear position of the gear transmission mechanism by engaging and disengaging the friction engagement device. In a hydraulic control device for a vehicle automatic transmission configured to perform switching between a switching valve that switches between supplying and discharging hydraulic pressure to the frictional engagement device according to the operating state; a hydraulic accumulator that is connected in the middle of an oil path that supplies and discharges hydraulic pressure to the frictional engagement device and has a back pressure chamber; It has a control boat and a spring, and the pressure regulation value is changed by the force of the hydraulic pressure supplied to the control boat and the spring force of the spring, and when the control boat is given line hydraulic pressure, it changes according to the line hydraulic pressure. an accumulator control valve that supplies hydraulic pressure to the back lT':v and supplies a constant hydraulic pressure determined by the spring force of the spring to the back pressure chamber when the control boat is connected to a drain boat, and a spring. In response to the balanced relationship between the spring force of the spring and the line oil pressure, when the line oil pressure is below a predetermined value, the control boat is connected to the drain boat, and when the line oil pressure is not below the predetermined value, the line oil pressure is connected to the control boat. This is achieved by a hydraulic control device of an automatic transmission for a vehicle, such as one having a choke valve for supplying the same.

Effects of the Invention According to the above-described configuration, the spring force of the spring incorporated in the accumulator control valve reduces the hydraulic pressure supplied to the back pressure chamber of the hydraulic accumulator during low-load operation when the line hydraulic pressure is below a predetermined value. This oil pressure can be independently set independently by the mounting load of the spring of the accumulator control valve or by changing the spring, regardless of the oil pressure supplied to the back pressure chamber of the hydraulic accumulator in other operating ranges, and The oil pressure supplied to the back pressure chamber of the hydraulic accumulator is controlled to a constant oil pressure as described above.tll-! The operating range is determined by the spring force built into the choke valve spring, and the operating range can be freely changed without being constrained by other control conditions by changing the mounting load of the choke valve spring or by changing the spring. Set.

DESCRIPTION OF EMBODIMENTS The present invention will now be described in detail with reference to embodiments with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the main parts of an embodiment of a hydraulic control device for a vehicle automatic transmission according to the present invention.

In FIG. 1, reference numeral 1 indicates a gear transmission 114M, which is constituted by a gear mechanism such as a planetary gear mechanism, and is engaged by a hydraulically operated friction engagement device 2 such as a clutch or brake. The gears are changed by releasing the button.

9- The friction engagement device 2 is selectively supplied with line oil pressure PL regulated by a line oil pressure control valve 3 from a speed change valve 4 via an oil path 5. The line hydraulic control valve 3 is itself a well-known hydraulic control valve, and when the accelerator pedal is depressed
In other words, a line oil pressure PL is generated that increases as the throttle opening increases.

The oil passage 5 is an oil passage for supplying and discharging hydraulic pressure to and from the frictional engagement device 2, and a hydraulic pressure combulator 6 is connected in the middle of the oil passage. The hydraulic accumulator 6 has one piston 9 that is movable in the axial direction of a large-diameter cylinder bore 7 and a small-diameter cylinder bore 8 that are arranged in series on the same axis. , each has a large-diameter flange portion 11 that fits into the large-diameter cylinder bore 7 via an O-ring 10 at one end, and a small-diameter flange portion 13 that fits into the small-diameter cylinder bore 8 via an O-ring 12 at the other end. The boat 14 is placed on the side of the large diameter flange portion 11.
Accumulator chamber 15 into which the hydraulic pressure of oil passage 5 is introduced
A back pressure chamber 16 is defined between the large diameter flange portion 11 and the small diameter flange portion 13. A compression coil spring 17 is installed between the piston 9 and the end wall of the small diameter cylinder bore 8 with a predetermined preload applied thereto.
Move the piston 9 downward in the figure, that is, toward the accumulator chamber 1.
5 is biased in the direction of decreasing the volume.

The piston 9 of the hydraulic accumulator 6 is actuated by an upward force in the figure due to the hydraulic pressure supplied to the hydraulic accumulator chamber 15 and a spring force of the compression coil spring 17, and a downward force in the figure due to the hydraulic pressure supplied to the back pressure chamber 16. As shown in the figure, the force due to the hydraulic pressure in the accumulator chamber 15 is greater than the total force due to the spring force of the compression coil spring 17 and the hydraulic pressure supplied to the back pressure chamber 16. When the size increases, the compression coil spring 17 is compressed and the oil is moved upward as shown in the figure to receive oil into the accumulator chamber 15 while increasing its volume to perform an accumulator action.

The back pressure chamber 16 is connected to the outlet boat 22 of the accumulator control valve 20 by an oil line 18 .

The hydraulic accumulator control valve 20 is configured as a spool valve and includes a valve element 21 that is movable in the vertical direction in the figure;
the hydraulic outlet port 22, a hydraulic inlet boat 23, a control boat 24, a feedback control boat 25 connected to the hydraulic outlet port 22 by a throttle passage 29, a drain boat 26, and a compression coil spring 27. There is. The accumulator control valve 20 is connected to the hydraulic inlet boat 2
3 is supplied with line hydraulic pressure PL from the line hydraulic control valve 3, and when the control boat 24 is connected to the drain, the line hydraulic pressure PL supplied to the hydraulic inlet port 23 is compressed]
P to a predetermined constant oil pressure determined by the spring force of the oil spring 27.
! The pressure is reduced, and the hydraulic pressure is supplied from the hydraulic outlet boat 22 through the oil line 18 to the back pressure chamber 16 of the hydraulic accumulator 6. On the other hand, when hydraulic pressure is being supplied to the IQ control boat 27I, it is supplied to the hydraulic inlet port 23. Line oil pressure PL
The hydraulic pressure is adjusted to a hydraulic pressure determined by the total force of the hydraulic pressure supplied to the control boat 24 and the spring force of the compression coil spring 27, and the hydraulic pressure is passed from the hydraulic outlet boat 22 through the oil path 18 to the back pressure of the hydraulic accumulator 6. It is designed to be supplied to the chamber 16.

Control boat 24 is connected to port 32 of choke valve 30 by oil line 28 . The choke valve 30 is configured as a spool valve and includes a valve element 31 that is movable in the vertical direction in the figure, the boat 32, and a hydraulic inlet boat 33.
It includes a drain boat 34, a port 36, and a compression coil spring 35, and the line hydraulic pressure PL is supplied to the hydraulic inlet port 33 from the line hydraulic control valve 3.
When the force due to the spring force of the helical compression spring 35 is smaller than the force due to the spring force of the helical compression spring 35, the valve element 31 is in the raised position as shown in the left half of the figure, connecting the boat 32 to the drain boat 34, whereas the line hydraulic pressure When the force due to PL is greater than the force due to the spring force on the compression coil spring 35, the valve element 3
1 is located in a lowered position as shown in the right half of the figure, and the boat 32 is separated from the drain boat 34 and connected to the hydraulic inlet boat 33.

13- Next, with reference to the graph shown in FIG. 2, the operation of the hydraulic control device constructed as described above will be explained in detail.

When the depression of the accelerator pedal, in other words, the throttle opening is below the predetermined value AC, the line oil pressure PL generated by the line oil pressure control valve 3 is below the predetermined value P2, so the valve element 31 of the choke valve 30 is activated by the compression coil. It is in the raised position due to the spring force of the spring 35, and at this time the port 3
2 is connected to the drain boat 34, and the control boat 24 of the accumulator control valve 20 is connected to the drain accordingly. Therefore, at this time, the accumulator control valve 2
0 generates at its hydraulic output port 22 a predetermined constant hydraulic pressure PI lower than the line hydraulic pressure PL determined by the spring force of the compression coil spring 27, and this hydraulic pressure is applied to the hydraulic accumulator 6.
is supplied to the back pressure chamber 16 of. Therefore, the oil pressure Pb supplied to the back pressure chamber 16 of the hydraulic accumulator 6 is the line oil pressure P
The compression coil spring 2714 of the accumulator control valve 20 until L reaches the switching setting oil pressure P2 of the choke valve 30.
- Line oil pressure PLJ determined by the spring force of: is maintained at a lower predetermined two constant oil pressure P1.

The line oil pressure PL generated by the line oil pressure control valve 3 increases in accordance with the increase in the amount of depression of the accelerator pedal, and when this reaches the switching setting pressure 12 of the choke valve 30 or more, the line oil pressure PL supplied to the oil pressure inlet boat 33 The valve element 31 of the choke valve 30 is placed in the lowered position against the spring force of the compression coil spring 35, and the boat 32 is disconnected from the drain boat 34 and connected to the hydraulic inlet port 33. At this time, the line oil pressure PL is supplied to the control boat 24 of the hydraulic accumulator 20, and the pressure regulation value of the A4-neumulator control valve 20 increases in accordance with the line oil pressure. In the illustrated embodiment, control boat 24
When the line hydraulic pressure PL is supplied to the control port 24, the land diameter of the valve element 21 on which the hydraulic pressure supplied to the feedback control boat 25 acts is larger than the land diameter of the valve element 21 on which the hydraulic pressure supplied to the feedback control boat 25 acts. The line hydraulic pressure PL supplied to the hydraulic inlet boat 23 is directly applied to the hydraulic output boat 22 of the accumulator control valve 20 without being reduced in pressure, and this line hydraulic pressure PL is supplied to the back pressure chamber 16 of the hydraulic accumulator 6. Become so. Therefore, when the line oil pressure PL reaches the switching setting pressure 12 of the choke valve 30 or more, in other words, when the amount of depression of the accelerator pedal is more than the predetermined value AC, the line oil pressure PL is supplied to the back pressure chamber 16 of the hydraulic accumulator 6. It becomes like this.

Note that the boat 36 of the choke valve 30 is equipped with a manual shift 1.
~Line oil pressure P only when the range is in reverse range
L is supplied, and as a result, in the reverse range, the valve element of the choke valve 30 is always held at the raised position regardless of the increase in the line oil pressure PL, and the back pressure chamber 16 of the hydraulic accumulator 6 has a predetermined amount of depression of the accelerator pedal. Even if the pressure exceeds the value AC, the 2-constant oil pressure P1 is supplied.

According to a configuration such as a double series, when the amount of depression of the accelerator pedal is less than a predetermined value, the back pressure chamber 16 of the hydraulic accumulator 6 is
The hydraulic pressure supplied to the back pressure chamber 16 has a large degree of freedom due to the spring force of the compression coil spring 27 of the hydraulic accumulator control valve 20, and is not restricted by other control requirements. The operating range for maintaining a predetermined constant pressure PI lower than the line oil pressure PL is set with a large degree of freedom by the spring force of the compression coil spring 35 of the choke valve 30 without being restricted by other control requirements.

In the embodiment described above, when the line oil pressure PL is equal to or higher than the switching setting pressure 12 of the choke valve 30, the line oil pressure PL is supplied to the back pressure chamber 16 of the hydraulic accumulator 6. If the land diameter of the valve element 21 on which the hydraulic pressure supplied to the control boat 24 acts is set smaller than the land diameter of the valve element 21 on which the hydraulic pressure supplied to the feedback control boat 25 acts, the line hydraulic pressure PL is equal to or higher than the switching set pressure 12 of the choke valve 30, the hydraulic pressure reduced according to the line hydraulic pressure is transferred to the back pressure chamber 1.
In the hydraulic control device according to the present invention, the diameter of each land of the valve element 21 of the accumulator control valve 217-0 may be set as described above.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto.
It will be apparent to those skilled in the art that various embodiments are possible within the scope of the invention.

[Brief explanation of drawings]

FIG. 1 shows hydraulic control iI of an automatic transmission for a vehicle according to the present invention.
FIG. 2 is a schematic diagram showing the essential parts of one embodiment of the device, and FIG. 2 is a graph showing the hydraulic characteristics of the automatic transmission hydraulic control device for IT vehicle delivery according to the present invention. 1... Gear transmission mechanism, 2... Friction engagement device, 3...
・Line hydraulic control valve, 4...speed change valve, 5...oil line,
6... Hydraulic accumulator, 7... Large diameter cylinder bore, 8... Small diameter cylinder bore, 9... Piston,
10...0 ring, 11...large diameter flange part, 12
...O-ring. 13...Small diameter flange part, 1/l...Boat, 15
...accumulator chamber, 16...back pressure chamber, 17.
. . . Compression coil spring, 18 . . Oil passage, 20 . 23...Hydraulic inlet boat, 24...Control port, 2
5...Feedback control port, 26...Dray
port, 27... compression coil spring, 28... oil passage, 29... throttle passage, 30... choke valve, 31...
...Valve element. 32...Port, 33...Hydraulic inlet boat, 34...
...Drain port, 35...Compression coil spring, 36
...Port patent applicant Toyota Motor Corporation representative Patent attorney Masaki Akashi

Claims (1)

[Claims] An automatic transmission for a vehicle, comprising a gear transmission mechanism and a hydraulically operated IfX friction engagement device, and configured to switch gears of the gear transmission mechanism by engaging and disengaging the JIIi friction engagement device. In the hydraulic control device, there is a line hydraulic pressure control valve that generates line hydraulic pressure that increases in response to an increase in the amount of depression of the accelerator pedal, and a hydraulic pressure supply to the friction engagement device described in #J according to the driving state of the vehicle. and a hydraulic accumulator having a back pressure chamber and connected in the middle of an oil path for supplying hydraulic pressure to the frictional engagement device.
It has a control boat and a spring, and the pressure regulation value is changed by the force of the hydraulic pressure supplied to the control boat and the spring force of the spring, and when the control boat is given line hydraulic pressure, it changes according to the line hydraulic pressure. an accumulator control valve that supplies hydraulic pressure to the back pressure chamber and supplies a constant hydraulic pressure determined by the spring force of the spring to the back pressure chamber when the control boat is connected to a drain boat; When the line oil pressure is below a predetermined value, the control boat is connected to the drain boat, and when the line oil pressure is not below the predetermined value, the line oil pressure is connected to the control boat. A hydraulic control device for an automatic transmission for a vehicle, having a choke valve for supplying power to the vehicle.