JPS6233152Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a hydraulic control system for an automatic transmission for an automobile, which can prevent various problems while the automobile is stopped in a driving range. Conventional automatic transmissions for automobiles generally have different driving ranges (ranges in which power can be transmitted from the input section of the automatic transmission to the output section or vice versa, such as drive range, second range, low range, and reverse range). ), hydraulic pressure is supplied via a manual valve to a hydraulic servo of a clutch that controls the connection between the output shaft of the hydraulic torque converter and the input shaft of the gear device, so that the clutch is in an engaged state. The problems with such automatic transmissions are listed below. (1) Even if the car stops, if the brake pedal is not kept pressed, the car will start moving. (2) In order to keep the car stopped, the driver must keep pressing the brake pedal or change the brake pedal to N (neutral) range. (3) Even when the vehicle is stopped, the resistance of the hydraulic torque converter acts as an engine load, so the idle speed must be set high, resulting in poor fuel efficiency. (4) After the hand brake is applied, when the brake pedal is released, the rear of the car bounces (rear dive), causing an unpleasant shock. The purpose of this invention is to solve the above-mentioned problems, improve fuel efficiency by eliminating the transmission of driving force when stopping artificially by stepping on the brake pedal, and eliminate the need to operate the shift lever for stopping. To this end, the present invention includes a frictional engagement device that transmits driving force, a control valve that supplies and discharges line hydraulic pressure to and from the frictional engagement device, and
A first sensor outputs a signal when the accelerator pedal is released, a second sensor outputs a signal when the vehicle speed is less than a predetermined vehicle speed, and a second sensor outputs a signal when the brake pedal is depressed. Third
The control valve operating means is configured to include a sensor and a control valve operating means that operates the control valve in response to signals output from each of these sensors to reduce the oil pressure to such an extent that engagement of the frictional engagement device becomes impossible. It is. Embodiments of the present invention will be described with reference to the drawings. In FIG. 1, a hydraulic torque converter 1 has a pump impeller 2, a stator 4 fixed to a stationary part via a one-way clutch 3, and a turbine runner 5, the pump impeller 2 being coupled to a crankshaft 6 of an engine. are doing. The direct coupling clutch 7 is provided in parallel to the hydraulic torque converter 1,
Controls the connection between the crankshaft 6 and the turbine runner 5. The turbine shaft 8 is connected to the turbine runner 5 and is connected via a front clutch 9 of a gearing 15 to a central shaft 10 and via a rear clutch 11 to an intermediate shaft 12 . The intermediate shaft 12 can be fixed to the housing 14 via a first brake 13 and a one-way clutch 17
and the second brake 18 as well as the housing 1
It can be fixed at 4. two planetary gears 19,
20 are sun gears 21, 22, pinions 23, 24, ring gears 25, 26, and carrier 2, respectively.
7, 28, and the sun gears 21, 22 are connected to the intermediate shaft 1.
2, the carrier 27 can be fixed to the housing 14 via a one-way clutch 33 and also via a third brake 34, and the ring gear 25 is coupled to the carrier 28. The ring gear 26 is coupled to the central shaft 10, and the output shaft 35 is coupled to the ring gear 25. The following table is an operation table for implementing each gear stage, where the numbers correspond to each engagement device, ◯ indicates the engaged state, and △ indicates that it operates only during engine braking.

[Table] Figure 2 shows a part of the hydraulic control circuit and the electronic control section. The oil guided through the strainer 40 is pressurized by an oil pump 41. The discharge side of the oil pump 41 is connected to a line pressure oil passage 47, and a well-known relief valve 42 and a primary regulating valve 43 are connected to the line pressure oil passage 47 to adjust the discharge pressure of the oil pump 41, that is, the line pressure Pl. Control. The well-known primary regulating valve 43 is an oil chamber 4 that is supplied with a throttle pressure Pth related to the intake system throttle valve opening.
4. Oil chamber 48 connected to line pressure oil passage 47 via orifice 46, and oil chambers 44, 48
and the spring force of the spring 49 to control the connection between the line pressure oil passage 47 and the port 50. As the throttle pressure Pth increases, the connection time between the line pressure oil passage 47 and the port 50 becomes shorter, and the line pressure Pl increases. Line pressure oil passage 47 is connected to input port 54 of manual valve 53. The manual valve 53 has a spool 55 that moves in the axial direction in conjunction with a shift lever in the driver's cab, and in the D (drive) range, which is an example of a driving range, the spool 55 connects the input port 54 to the output port 56. are doing. The output port 56 is connected to a hydraulic servo 57 of the clutch 9. The solenoid valve 60 is connected to the line pressure oil passage 47
A port 61, a drain 62, a solenoid 63, and a valve body 64 whose position is controlled by the solenoid 63 to open and close the port 61 are provided.
When the solenoid 63 is energized, the valve body 6
4 is away from the port 61, and the oil passage 47 is separated from the port 61.
The line pressure Pl of the line pressure oil passage 47 is discharged and the hydraulic servo 5
7 is not supplied with line pressure Pl, and the clutch 9 is in a released state. That is, the connection between the input section and the output section of the automatic transmission is disconnected. Furthermore, when the solenoid 63 is deenergized, the port 61 is closed by the valve body 64, so that the line pressure Pl is supplied to the hydraulic servo 57 via the line pressure oil passage 47 and the manual valve 53, and the clutch 9 is activated. The input section and the output section of the automatic transmission are in a connected state. The accelerator throttle sensor 68 detects depression of an accelerator pedal (not shown), and becomes conductive (ON) when the accelerator pedal is depressed, and becomes non-conductive (OFF) when the accelerator pedal is released. . The brake oil pressure sensor 69 detects whether the brake oil pressure is above a predetermined value,
Turns ON when the brake oil pressure is above a predetermined value, that is, when the brake pedal is depressed, and turns OFF when the brake oil pressure is less than the predetermined value, that is, when the brake pedal is released.
becomes. The vehicle speed sensor 70 detects the vehicle speed, and turns ON when the vehicle speed is greater than a predetermined value, and turns OFF when the vehicle speed is approximately zero, that is, below the predetermined value. The control unit 73 consisting of an electronic circuit includes a sensor 68,
In response to signals 69 and 70, the current to the solenoid 63 of the electromagnetic valve 60 is controlled. Accelerator throttle sensor 68 is OFF, brake oil pressure sensor 69 is ON, and vehicle speed sensor 70
The solenoid 63 of the electromagnetic valve 60 is deenergized except when is OFF, the line pressure oil passage 47 is not connected to the drain 62, and in the case of the D range,
Line pressure Pl is input port 54 of manual valve 53
and is sent to the hydraulic servo 57 through the output port 56 to maintain the clutch 9 in the engaged state. Accelerator throttle sensor 68 is OFF, brake oil pressure sensor 60 is ON, and vehicle speed sensor 70
is OFF, that is, when the accelerator pedal is released, the brake pedal is depressed, and the vehicle speed is approximately zero, in other words, when the vehicle is stopped or just before stopping, the solenoid 63 of the solenoid valve 60 is turned off. The line pressure of the line pressure oil passage 47 is
Pl is discharged through port 61 and drain 62, clutch 9 is disengaged, and the connection between the input and output parts of the automatic transmission is severed. The solenoid 63 is then activated by the accelerator throttle sensor 68.
ON, until the brake oil pressure sensor 69 is OFF and the vehicle speed sensor is OFF, that is, until the condition that the accelerator pedal is depressed and the brake pedal is released and the vehicle speed is approximately zero is met, in other words, the vehicle starts driving. When this condition is met, it is deenergized again and the line hydraulic pressure Pl is applied to the hydraulic servo 5 via the manual valve 53.
7, and the clutch 9 is brought into engagement. The following table shows the relationship between the states of the manual valve 53, accelerator throttle sensor 68, brake oil pressure sensor 69, and vehicle speed sensor 70 and the state of the clutch 9. Regarding the manual valve 53, when the manual valve 53 is in the traveling range position, it is indicated as ON, and when it is in the N range position, it is indicated as OFF. Regarding the clutch 9, when the clutch 9 is in the engaged state, it is indicated as ON, and when it is in the disengaged state, it is indicated as ON. OFF when in
It is expressed as Also, ↑ indicates the same state as the upper row, and * indicates an arbitrary state.

[Table] When the A1 depresses the brake pedal while driving,
A2 when driving normally, A3 when driving while depressing the brake pedal, A4 when driving,
When A5 depresses the brake pedal while driving, A6
indicates when the engine is braking, A7 indicates when the vehicle is stopped or is about to stop, A8 indicates when the vehicle is stopped or traveling at an extremely low speed, and A9 indicates when the manual valve 53 is not in the travel range position. For clutches other than A7, the clutch 9 is maintained in the engaged state, and for A7, the clutch 9 is maintained in the released state, and once A7 is reached and the clutch 9 is in the released state, the clutch 9 is kept in the released state until the next time A4 is reached. maintained,
At A4, the clutch 9 becomes engaged again. As described above, according to the present invention, when the brake pedal is depressed and the acceleration pedal is simultaneously released and the vehicle speed falls below a predetermined vehicle speed, the hydraulic pressure for the friction engagement device is reduced by the control valve, and as a result, , the frictional engagement device is released and the connection between the engine and the drive wheels is disconnected. Therefore, even if the driver releases the brake pedal while the shift lever is maintained in a predetermined driving range position, the vehicle is prevented from moving away, and the driver continues to press the brake pedal to keep the vehicle stopped. There is no need to change to N range, and the load on the engine is suppressed, improving fuel efficiency without the need to set the idling speed to a high level.Furthermore, the rear dive when releasing the brake pedal after applying the hand brake is also improved. It can be prevented. In addition, with this invention, the friction engagement device is not released when the brake pedal is stopped other than when the brake pedal is artificially stopped, so there is no disconnection between the engine and the drive wheels. As a result, the engine and drive wheels remain connected even when the engine stops, so the engine's driving force can maintain the stopped state.
This prevents inconveniences such as the vehicle inadvertently backing up. In addition, in this invention, the output of a signal refers to any situation other than when the sensor changes from an OFF state to an ON state.
It also means a change in electrical state due to a change from an ON state to an OFF state, and is not limited to the example described in the above embodiment.

[Brief explanation of the drawing]

Figure 1 is a skeleton diagram of an embodiment of the present invention, Figure 2 is a skeleton diagram of an embodiment of the present invention.
The figure is a diagram showing a hydraulic circuit and its control section according to an embodiment of the present invention. 9...Clutch (frictional engagement device), 47...Line pressure oil path, 60...Solenoid valve (control valve), 68...
... accelerator throttle sensor, 69 ... brake oil pressure sensor, 70 ... vehicle speed sensor, 73 ... control section (control valve operating means).

Claims (1)

[Scope of utility model registration request] A friction engagement device that transmits driving force, a control valve that supplies and discharges line hydraulic pressure to and from the friction engagement device, a first sensor that outputs a signal when the accelerator pedal is released, and a first sensor that outputs a signal when the accelerator pedal is released. a second sensor that outputs a signal when the vehicle speed is below a predetermined speed, a third sensor that outputs a signal when the brake pedal is depressed, and a signal output from each of these sensors to control the control valve. 1. A hydraulic control device for an automatic transmission, comprising: a control valve operating means for lowering hydraulic pressure to such an extent that engagement of a frictional engagement device becomes impossible.