JPH052860B2 - - 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 particularly to a back pressure control device for an accumulator incorporated in the hydraulic control device to reduce shift shock.

A vehicle automatic transmission used in a vehicle such as an automobile has a gear transmission mechanism constituted by a planetary gear mechanism or the like, and a plurality of friction engagement devices such as a clutch and a brake. The automatic transmission is configured such that one of a plurality of gears is achieved by selectively switching the engagement, and this automatic transmission is conventionally known in various configurations. Hydraulic control devices with various configurations are known as devices for operating machines.

The hydraulic control device for automatic transmissions for vehicles consists of a line hydraulic control valve that generates line hydraulic pressure that increases in proportion to the throttle opening of the throttle valve installed in the intake system of the internal combustion engine, and a line hydraulic pressure that increases in proportion to the throttle opening of the throttle valve installed in the intake system of the internal combustion engine. at least one switching valve for switching the supply of hydraulic pressure to the plurality of frictional engagement devices, and in response to switching of the switching valve, newly applying hydraulic pressure to at least one of the plurality of frictional engagement devices. The hydraulic pressure previously supplied to the frictional engagement device is now discharged.

In the automatic transmission for a vehicle as described above, when the frictional engagement device is suddenly engaged, a shock generally referred to as a shift shock occurs due to the engagement of the frictional engagement device. For this reason, a cylinder-piston type accumulator is connected in the middle of the oil path that supplies hydraulic pressure from the switching valve to the frictional engagement device, and the accumulator action of the accumulator causes the friction engagement device to be engaged. It has been conventional practice to reduce the rate of increase in hydraulic pressure to avoid sudden engagement, and to reduce the shift shock associated with engagement of the frictional engagement device.

The hydraulic pressure at which the frictional engagement device in a vehicle automatic transmission completes engagement varies depending on the transmission torque of the frictional engagement device, and therefore this hydraulic pressure is required when the internal combustion engine is operated at low load and low rotation speed. It is low when the transmission torque of the frictional engagement device is small, such as when the transmission torque of the frictional engagement device is small, and becomes high when the transmission torque of the frictional engagement device is large, such as when the internal combustion engine is operated at a high load and high rotation speed. Therefore, under all operating conditions,
In order to obtain the shift shock reducing effect of the accumulator, the accumulator must be configured to exert an accumulator action from a relatively small hydraulic pressure to a relatively large hydraulic pressure to control the rising speed of the hydraulic pressure. In contrast, conventionally, line hydraulic pressure or hydraulic pressure derived from the line hydraulic pressure is introduced into the back pressure chamber of the accumulator, and the operating hydraulic pressure range of the accumulator is changed mainly depending on the load of the internal combustion engine.

However, during idling operation, the change in engine speed due to changes in throttle opening is larger than during load operation, so the accumulator performs a preferable accumulator action when the engine is idling at the normal idling speed. With this configuration, when the idle speed is higher than the normal idle speed, that is, during idle up operation, the shift range of the automatic transmission is changed from the N range to the driving range such as the D range or the R range. If the gear is switched to , the engagement of the frictional engagement device (clutch) will not be completed in the accumulator action area, resulting in a large shift shock.

The present invention appropriately controls the hydraulic pressure supplied to the back pressure chamber of the accumulator so as to reduce the shift shock caused by the engagement of the frictional engagement device not only during idle operation at a normal idle speed but also during idle operation. An object of the present invention is to provide a hydraulic control device for an automatic transmission for a vehicle, which is equipped with back pressure control means.

According to the present invention, the present invention has a gear transmission mechanism and a plurality of frictional engagement devices, and the engagement of the frictional engagement devices is selectively switched to change one of the plurality of gears. A hydraulic control device for an automatic transmission for a vehicle configured to achieve any of the following: an accumulator having a back pressure chamber connected in the middle of an oil path for supplying hydraulic pressure to at least one of the plurality of frictional engagement devices; an accumulator control valve that regulates the hydraulic pressure applied to the back pressure chamber;
A hydraulic control device for an automatic transmission for a vehicle, comprising a control means that controls the pressure regulation value of the accumulator control valve according to engine speed and vehicle speed, and increases the pressure regulation value during idle up compared to normal idle operation. achieved by.

According to the above-described configuration, the back pressure of the accumulator is increased when the idle is up compared to during normal idling, so that the shift shock is not affected when starting from the normal idling state or when starting from the idle up state. Shifting is performed with a small number of changes.

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

The attached figure is a schematic configuration diagram showing one embodiment of a hydraulic control device for a vehicle automatic transmission according to the present invention. In this figure, only the main parts of the present invention are specifically shown, and other parts that are already configured in a well-known manner are omitted by blocks. ing. In this figure, 1 indicates an internal combustion engine, and 2 indicates a vehicle automatic transmission connected to the internal combustion engine 1. The automatic transmission for a vehicle includes a hydraulic torque converter 3 and a gear transmission mechanism 4 configured with a planetary gear mechanism. The gear transmission mechanism 4 can change its transmission mechanism in several ways by means of a plurality of well-known frictional engagement devices such as clutches and brakes.
Accordingly, one of the plurality of gears is selectively achieved. A clutch, which is one of the plurality of frictional engagement devices, is designated by the reference numeral 5. The clutch 5 is supplied with hydraulic pressure and engaged to transmit torque when the shift range of the automatic transmission 2 is changed from the N range to a driving range such as the D range or the R range.

Reference numeral 10 indicates a hydraulic control device that operates the automatic transmission 1 and controls its operation. The hydraulic control device 10 includes an oil pump 11, a manual range switching valve 12 for switching shift ranges, a line hydraulic control valve 13, a throttle hydraulic control valve 14, two shift switching valves 15 and 16, and the like.

The line oil pressure control valve 13 is supplied with oil pressure from the oil pump 11 and generates line oil pressure that increases in proportion to the throttle opening of a throttle valve (not shown) provided in the intake system of the internal combustion engine 1. ing.

The throttle oil pressure control valve 13 is designed to generate a throttle oil pressure that increases in proportion to the throttle opening at a value lower than the line oil pressure.

The hydraulic control device 10 transmits the line hydraulic pressure generated by the line hydraulic pressure control valve 13 through an oil passage 17, a throttle valve 18, and an oil passage 19 when the shift range is changed from the N range to a driving range such as the D range or the R range. It is adapted to be supplied to clutch 5. The throttle valve 18 has a parallel combination structure of a check throttle orifice in which a check ball 18c is combined with a throttle orifice 18a and a throttle orifice 18b in order to individually adjust the speed of supplying and discharging hydraulic pressure to the clutch 5. are doing.

Further, an accumulator 21 is connected to the middle of the oil passage 19 by an oil passage 20. The accumulator 21 has a large-diameter cylinder chamber 22 and a small-diameter cylinder chamber 23 formed in a valve body 24 in series, and receives a piston 25 in these cylinder chambers so as to be movable in the vertical direction as shown in the figure. piston 2
5 is a flange portion 2 that fits into the large diameter cylinder chamber 22;
6 and a cylindrical portion 27 that fits into the small diameter cylinder chamber 23, and the flange portion 26 defines an accumulator chamber 28 on one side and a back pressure chamber 29 on the other side. There is. Accumulator room 28
is connected to the oil passage 20 through a port 31 of a plate 30 provided at its end, and is supplied with the same hydraulic pressure as that supplied to the clutch 5. The piston 25 is flexibly supported by the compression coil spring 32 and the hydraulic pressure supplied to the back pressure chamber 29 against the hydraulic pressure acting on the accumulator chamber 28 . The back pressure chamber 29 is supplied with hydraulic pressure controlled by a throttle modulator valve 33, an accumulator control valve 34, and an on-off valve 35, which will be described below.

The throttle modulator valve 33 has a spool 36 within a bore formed in the valve body 24;
The land portion 37 controls the degree of communication between the inlet port 38 and the outlet 39. Throttle oil pressure is supplied to the inlet port 38 from the throttle control valve 14 via an oil path 40, and the oil pressure appearing at the inlet port 38 is introduced into the chamber 43 via an oil path 41 and a port 42, and the oil pressure appearing at the outlet port 43 is The oil is introduced into the chamber 45 through an oil hole 44 formed in the spool 36. The spool 36 is driven by the balance between the pressing force of the hydraulic pressure introduced into the chamber 45, the pressing force of the hydraulic pressure introduced into the chamber 43 acting in opposition to this, and the spring force of the compression coil spring 46. It's summery.

As a result, the throttle modulator valve 33 supplies to its outlet port 39 an oil pressure having the same pressure as the throttle oil pressure until the throttle oil pressure reaches a predetermined value, and when the throttle oil pressure exceeds the predetermined value, the pressure equal to the predetermined value is applied. Generates hydraulic pressure with . This oil pressure is now referred to as throttle modulate oil pressure.

The accumulator control valve 34 is connected to the valve body 24
It has a spool 47 in a bore formed in the hole, and its land portion 48 connects an inlet port 49 and an outlet port 5.
The degree of communication with 0 is controlled.
Line hydraulic pressure is supplied to the inlet port 49 from the line hydraulic pressure control valve 12 via an oil passage 51, and the oil pressure appearing at the inlet port 49 is introduced into the chamber 54 from a port 53 via an oil passage 52 having a throttle 73 in the middle. The oil pressure appearing at the outlet port 50 passes through an oil passage 55 having a throttle 74 in the middle, and then enters the chamber 5 from the port 56.
7 will be introduced. Also, the accumulator control valve 34
It has another chamber 58 in which the outlet port 3 of the throttle modulator valve 33 is connected.
The hydraulic pressure appearing at 9 is introduced from port 60 via conduit 59. The spool 47 is driven by the balance between the pressing force due to the hydraulic pressure introduced into the chamber 57, the pressing force due to the hydraulic pressure introduced into the chambers 54 and 58 acting in opposition to this, and the spring force of the compression coil spring 61. It's becoming like that. The port 50 is connected to the back pressure chamber 29 by an oil passage 67.

The oil passage 52 is connected to the on-off valve 35 in the middle thereof, and selectively connected to the drain port 62 by the on-off valve 35. Open/close valve 3
5 is configured as a solenoid valve and includes a valve element 65 driven by a solenoid 63 and a spring 64. When the solenoid 63 is not energized, the valve element 65 is pushed down by the spring force of the spring 64 to close the port 66. As a result, the oil passage 52 is separated from the drain port 62, and the solenoid 6
When the valve element 3 is energized, the valve element 65 is pulled up against the force of the spring 64 to connect the oil passage 52 to the drain port 62.

When the on-off valve 35 is closed, the line hydraulic pressure is introduced into the chamber 54, so that the spool 47 of the accumulator control valve 34 is brought to the maximum open position as shown in the figure. Oil pressure appears at outlet port 50 at the same pressure as the introduced line oil pressure. On the other hand, when the on-off valve 35 is open, no line oil pressure is introduced into the chamber 54, so that the line oil pressure supplied to the inlet port 49 is converted into the throttle modulate oil pressure introduced into the chamber 58 from the port 60. A proportionally modified hydraulic pressure is thus generated at the outlet port 50. If necessary regarding the characteristics of this hydraulic pressure, please refer to Japanese Patent Application No. 55-39536 filed by the same applicant as the present applicant.
Please refer to the issue.

Current is selectively supplied to the solenoid 63 of the on-off valve 35 from a battery power source 68 via a switch 69. The switch 69 is opened and closed by an electric control device 70. The control device 70 receives an engine speed signal generated by an engine speed sensor 71 attached to the internal combustion engine 1 and an automatic transmission 2.
The switch 69 is opened only when the vehicle speed is zero and the engine speed is above a predetermined value.

Therefore, when the vehicle speed is zero, that is, during idling, when the engine speed is below a predetermined value, the switch 69 is closed and the solenoid 63 is energized, so that the on-off valve 35 is opened. Therefore, line hydraulic pressure is not supplied to the chamber 54, and the outlet port 50 of the accumulator control valve 34 is connected to the inlet port 49.
The line hydraulic pressure supplied to the port 60 is proportionally corrected by the throttle modulate hydraulic pressure supplied to the port 60 to generate a hydraulic pressure lower than the line hydraulic pressure, and this hydraulic pressure passes through the oil passage 67 to the back pressure chamber of the accumulator 21. Introduced on 29th.

On the other hand, during idling operation, when the engine speed is above a predetermined value, the switch 69 is open and the energization to the solenoid 63 is stopped, which closes the on-off valve 35 and supplies line oil pressure to the chamber 54. As a result, the same oil pressure as the line oil pressure introduced into the inlet port 49 is generated at the outlet port 50 of the accumulator control valve 34, and this oil pressure is passed through the oil path 67 to the back pressure chamber 2 of the accumulator 21.
introduced in 9.

As mentioned above, during idle operation, when the engine speed is higher than a predetermined value, that is, during idle up operation, the oil pressure introduced into the back pressure chamber 29 is higher than during normal idle operation, so that the accumulator 21 is activated. The hydraulic range in which the accumulator operates increases, and as a result, during idle-up operation, the shift range of the automatic transmission 2 is switched from the N range to a driving range such as the D range or R range, and hydraulic pressure is supplied to the clutch 5. When engaged, the accumulator 21 performs an effective accumulator action, reducing the shift shock at this time.

Also, during normal idle operation, the hydraulic pressure introduced into the back pressure chamber 29 of the accumulator 21 is lower than during idle up operation.
During this idle operation, the accumulator 21
The operating range of the automatic transmission 2 does not become excessive, and the shift range of the automatic transmission 2 during normal idling is N.
Even when the range is changed to a driving range such as D range or R range, the accumulator 21 exhibits an effective accumulator action without degrading the responsiveness of the change and reduces the shift shock at this time.

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

[Brief explanation of drawings]

The attached figure is a schematic configuration diagram showing one embodiment of a hydraulic control device according to the present invention. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 2... Automatic transmission, 3... Fluid torque converter, 4... Gear transmission mechanism, 5... Clutch, 10... Hydraulic control device, 11... Oil pump,
12...Manual shift switching valve, 13...Line oil pressure control valve, 14...Throttle oil pressure control valve, 15,
16... Shift switching valve, 18... Throttle valve, 21... Accumulator, 25... Piston, 28... Accumulator chamber, 29... Back pressure chamber, 32... Compression coil spring,
33...Throttle modulator valve, 34...Accumulator control valve, 35...Opening/closing valve, 69...Switch, 70...Electric control device, 71...Engine speed sensor, 72...Vehicle speed sensor.

Claims (1)

[Claims] 1 comprising a gear transmission mechanism and a plurality of frictional engagement devices, and configured such that one of the plurality of gears is achieved by selectively switching the engagement of the frictional engagement devices. A hydraulic control device for an automatic transmission for a vehicle, comprising: at least one switching valve that switches the supply of hydraulic pressure to the plurality of frictional engagement devices according to the driving state of the vehicle; and the plurality of frictional engagement devices. an accumulator having a back pressure chamber connected in the middle of an oil path that supplies hydraulic pressure to at least one of the above, an accumulator control valve that regulates the hydraulic pressure applied to the back pressure chamber, and an accumulator control valve that controls the accumulator according to the engine speed and vehicle speed. A hydraulic control device for an automatic transmission for a vehicle, comprising a control means for controlling a pressure regulation value of a valve and increasing the pressure regulation value during idle up compared to normal idling operation.