JP2003002180A - Control device for gear-in parking brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a gear-in parking brake to be able to obtain sufficient braking power in a short period time after cutting of an engine. SOLUTION: The control device of a gear-in parking brake 70 to be combined with a power transmission device with a clutch mechanism which is automatically cut-off when the engine is stopped, is equipped with a hydraulic circuit 19 which supplies a pressure oil to control activation and non-activation of the gear-in parking brake. The gear-in parking brake 70 enters non-activation status by continuously being supplied with the pressure oil from a hydraulic power circuit 19 when the engine is driving, and enters activation status when the engine is stopped and oil pressure of the hydraulic power circuit 19 is declined. Furthermore, the hydraulic power circuit 19 is equipped with a hydraulic downturn facilitation means to lower the oil pressure in a short period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a gear-in parking brake, which is combined with a power transmission device having a clutch mechanism that is automatically disengaged when the engine is stopped. The present invention relates to a control device for a gear-in parking brake that shortens the time required to obtain a braking force.

[0002]

2. Description of the Related Art In a large vehicle such as a truck, a fluid coupling (fluid coupling) and a wet multi-plate clutch (friction type shift clutch) are used together as a power transmission device for transmitting engine power to a transmission side. What has been done is proposed.

In such a power transmission device, since the wet multi-plate clutch is automatically engaged and disengaged when the driver performs a gear shift operation, the driver can perform a gear shift operation without performing a clutch operation.

By the way, in a vehicle equipped with such a power transmission device, when the engine is stopped, the oil pump which supplies pressure oil to the wet multi-plate clutch and is in contact with it stops, so that the wet multi-plate clutch automatically operates. Be cut off. Therefore, in order to prevent problems due to freezing of the side brakes during cold weather, the vehicle is parked by stopping the engine without using the side brakes while keeping the gears of the transmission in any stage. I couldn't park.

That is, when the engine is stopped in the gear-in state, the wet multi-plate clutch is automatically disengaged, and the wet multi-plate clutch idles, resulting in a braking effect (braking force).
Can't get

Therefore, the present applicant has previously filed Japanese Patent Application No. 2001-2001.
In No. 121300, we proposed a gear-in parking brake. This brake is provided on the input shaft of the transmission, and when the engine is operating, pressure oil is constantly supplied from the oil pump to make it inactive, and when the engine is stopped, the oil pump stops and the hydraulic pressure in the hydraulic circuit drops. It is in an operating state.

[0007]

However, in this gear-in parking brake, braking force cannot be obtained unless the hydraulic pressure of the hydraulic circuit is sufficiently reduced, and the hydraulic pressure drop after the oil pump is stopped is due to the oil tank of the oil itself. There is a problem that it takes time to obtain sufficient braking force after the engine is stopped because it relies on the return (leak) to.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a gear-in parking brake control device capable of obtaining a sufficient braking force in a short time after the engine is stopped.

[0009]

In order to achieve the above object, the present invention provides a power transmission device provided with a clutch mechanism interposed between an engine and a transmission and automatically disengaged when the engine is stopped. A control device for a gear-in parking brake, which operates in combination with the engine when the engine is stopped in a gear-in state, the oil supplying pressure oil for controlling the operation / non-operation of the clutch mechanism and the gear-in parking brake. A hydraulic circuit including a pump is provided, and the gear-in parking brake is in a non-operating state because pressure oil is constantly supplied from the hydraulic circuit when the engine is operating. When the engine is stopped, the oil pump is stopped and the hydraulic circuit is stopped. When the oil pressure in the
The hydraulic circuit further comprises a hydraulic pressure reduction promoting means for reducing the hydraulic pressure in a short time after the engine is stopped.

According to this, the oil pressure in the hydraulic circuit is decreased by the oil pressure decrease promoting means in a short time after the engine is stopped. That is, a sufficient braking force can be obtained in a short time after the engine is stopped.

The clutch mechanism includes a fluid coupling connected to the output shaft of the engine, a lockup clutch for mechanically connecting and disconnecting the input and output sides of the fluid coupling, and the fluid coupling and the transmission. And a friction type speed change clutch provided to the lockup clutch or the friction type speed change clutch. It may consist of valve means for switching to a closed state for discharging to the tank side, and an electronic control unit for opening and closing the valve means for a predetermined time after stopping the engine in a gear-in state.

The valve means switches between an open state in which pressure oil is supplied to the friction type speed change clutch in accordance with the applied pilot oil pressure and a closed state in which pressure oil is discharged from the friction type speed change clutch. A switching valve, and a pilot solenoid valve that switches between an open state in which pilot hydraulic pressure is supplied to the clutch switching valve according to an applied electric signal and a closed state in which oil is discharged from the clutch switching valve,
The electronic control unit may open and close the pilot solenoid valve for a predetermined time after stopping the engine in a gear-in state.

The gear-in parking brake may be provided on the input shaft of the transmission.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

First, a schematic structure of a power transmission device in which a gear-in parking brake according to the present embodiment is combined will be described with reference to FIG.

As shown in the figure, a transmission T / M is connected to the engine E via a clutch mechanism 1. The clutch mechanism 1 comprises a fluid coupling (fluid coupling) 2 and a wet multi-plate clutch (friction type speed change clutch) 3.
The fluid coupling 2 is provided on the upstream side of the power transmission path from the engine E to the transmission T / M, and the wet multi-plate clutch 3 is provided in series on the downstream side thereof. The fluid coupling here is a broad concept including a torque converter, and the torque converter is actually used also in this embodiment.

The fluid coupling 2 includes a pump portion 4 that rotates integrally with a casing 18 connected to an output shaft (crankshaft) 1a of the engine E, and a pump portion 4 inside the casing 18 that faces the pump portion 4 and is connected to an input side of the clutch 3. Connected turbine part 5
And a stator portion 6 interposed between the turbine portion 5 and the pump portion 4. Also, in this fluid coupling 2,
A lock-up clutch 7 for mechanically disconnecting and connecting the pump unit 4 and the turbine unit 5 is provided, and the lock-up clutch 7 is operated by pressure oil from a hydraulic circuit 19.

The wet multi-plate clutch 3 has its input side connected to the turbine section 5 via the input shaft 3a, its output side connected to the input shaft 8 of the transmission T / M, and the fluid coupling 2 and the transmission T.
/ M, and is normally urged in the disconnecting direction by a spring (not shown), and is contacted by the pressure oil from the hydraulic circuit 19.

The transmission T / M has an input shaft 8, an output shaft 9 arranged coaxially with the input shaft 8, and an auxiliary shaft 10 arranged in parallel with these. An input main gear 11 is provided on the input shaft 8. The output shaft 9 includes a first speed main gear M1, a second speed main gear M2, a third speed main gear M3, a fourth speed main gear M4,
The reverse main gear MR and the reverse main gear MR are axially supported, respectively.
The main speed gear M6 is fixed. The auxiliary shaft 10 has an input auxiliary gear 12 meshing with the input main gear 11 and a first speed main gear M1.
First gear sub gear C1 meshing with second gear main gear M2, second gear sub gear C2 meshing with second gear main gear M2, third gear sub gear C3 meshing with third gear main gear M3, and fourth gear meshing with fourth gear main gear M4. Secondary gear C4
And a reverse auxiliary gear CR that meshes with the reverse main gear MR via an idle gear IR, and
A sixth speed sub gear C6 that meshes with the sixth speed main gear M6 is pivotally supported.

According to this transmission T / M, when the sleeve S / R1 spline-engaged with the hub H / R1 fixed to the output shaft 9 is spline-engaged with the dog DR of the reverse main gear MR, the output shaft 9 is moved. When the sleeve S / R1 is reversely rotated and the dog D1 of the first-speed main gear M1 is spline-engaged, the output shaft 9 is rotated at the first speed. When the sleeve S / 23 spline-engaged with the hub H / 23 fixed to the output shaft 9 is spline-engaged with the dog D2 of the second-speed main gear M2, the output shaft 9 rotates at the second speed, and the sleeve S When / 23 is spline-engaged with the dog D3 of the third-speed main gear M3, the output shaft 9 rotates at the third speed.

The hub H / 4 fixed to the output shaft 9
When the sleeve S / 45 meshed with 5 is spline meshed with the dog D4 of the 4th-speed main gear M4, the output shaft 9 rotates at the 4th speed, and the sleeve S / 45 is splined with the dog D5 of the input main gear 11. When meshed, the output shaft 9 rotates at a speed corresponding to 5th speed (direct connection). Then, the sleeve S6 spline-engaged with the hub H6 fixed to the counter shaft 10 is
When the dog D6 of the auxiliary speed gear C6 is spline-engaged, the output shaft 9 rotates at the sixth speed.

Each of the sleeves S is manually operated by the shift lever 21 in the operator's cab via a shift fork and a shift rod (not shown).

The shift lever 21 is provided with a knob switch 20. That is, in this embodiment, in order to detect the start timing of the shift operation by the driver or to determine the timing to start the disengagement of the clutch 3, in the shift lever 21 in the driver's cab, the shift knob is slightly shifted in the shift direction. A knob switch 20 is provided between the lever and the shift knob. When the shift knob is swung prior to the operation of the lever during a gear shift operation by the driver, the knob switch 20 is turned on, and the clutch disengagement is started with this signal.

The neutral and the gear stage due to the operation of the shift lever 21 are detected by the gear-in detecting means 21s, and the detected neutral and gear stage states are input to the electronic control unit 22.

The amount of depression of the accelerator pedal 23 is detected by the sensor 24, and the amount of depression is input to the electronic control unit 22. The amount of depression of the brake pedal 25 is detected by the sensor 26, and the amount of depression is input to the electronic control unit 22.

The input main gear 11 of the transmission T / M or the input sub-gear 12 meshing with the input main gear 11 has a transmission T / M.
An input shaft rotation sensor 27 for detecting the rotation speed of the M input shaft 8 is provided, and a turbine section rotation sensor 2 for detecting the rotation speed of the turbine section 5 is provided on the input side of the wet multi-plate clutch 3.
8, a casing 18 connected to the output shaft 1a of the engine E is provided with an engine rotation sensor 29 for detecting the rotation speed of the engine E, and an output shaft 9 of the transmission T / M.
Is provided with a vehicle speed sensor 74 for detecting the vehicle speed. The detection values of these sensors 27, 28, 29, 74 are input to the electronic control unit 22.

Next, details of the fluid coupling 2 and the lockup clutch 7 will be described with reference to FIG.

In the figure, a pump portion 4 is integrally provided in a casing 18 connected to an output shaft (crankshaft) 1a of the engine E. The pump portion 4 uses the bearing 29 to input the input shaft 3 of the wet multi-plate clutch (friction type speed change clutch) 3.
It is rotatably provided with respect to a. Also the casing 18
Inside, a turbine unit 5 is provided facing the pump unit 4 and connected to the input shaft 3 a of the clutch 3. In the figure, the stator portion 6 is omitted for convenience of explanation.

The turbine spring 5 includes a damper spring 3
The clutch disc 31 is connected via 0. The clutch disc 31 is provided on the outer periphery of the turbine hub 32 of the turbine unit 5 so as to face the casing 18 so as to be relatively rotatable and axially slidable, and the outer periphery of the clutch disc 31 facing the casing 18 side. A clutch facing 33 is attached to the part.

The clutch disc 31 forms an outer chamber 34 between the casing 18 and the clutch disc 31, and an inner chamber 35 between the turbine section 5 and the clutch disc 31.

An inner passage 36 is formed in the input shaft 3a,
An outer passage 37 is formed on the outer circumference of the input shaft 3a.

In the fluid coupling 2, when the lockup clutch 7 is disengaged, the electronic control unit 22 causes the pressure oil to flow from the inner passage 36 to the outer chamber 34 between the casing 18 and the clutch disc 31, and the outer chamber 34. As shown by the arrow 38 in the upper half of the figure, the turbine section 5 and the pump section 4 are
Which flows inside to transmit the rotation of the pump unit 4 to the turbine unit 5,
Some flow through the bearing 29 to the outer passage 37. Further, when the lockup clutch 7 is brought into contact, the flow of the pressure oil is switched in the opposite manner to the above. That is, the pressure oil passes from the outer passage 37 through the bearing 29 to the lower half in the figure by the arrow 39.
As shown by, it flows in the pump section 4 and the turbine section 5 and flows into the inner chamber 35. As a result, the clutch disc 31 is pressed toward the casing 18 by the pressure oil in the inner chamber 35, and the clutch facing 33 is moved to the casing 18 side.
And the rotation of the casing 18 is transmitted from the clutch disc 31 to the turbine unit 5 via the damper spring 30, and the pump unit 4 and the turbine unit 5 are integrally connected.

In the wet multi-plate clutch 3, a plurality of clutch plates 41 are alternately splined on the input side and the output side in a clutch casing 40 filled with oil, and the clutch plates 41 are connected to each other by a clutch piston. The clutch is engaged or disengaged by 42 to disconnect or connect the clutch. The clutch piston 42 is always biased to the disengaged side by the clutch spring 43, and the clutch 3 is brought into contact with the clutch piston 42 when a hydraulic pressure exceeding this is applied to the clutch piston 42.

FIG. 4 shows details of the hydraulic circuit 19 for controlling the operation / non-operation of the fluid coupling 2, the lockup clutch 7, and the wet multi-plate clutch 3.

As shown in the figure, the oil in the oil tank 45 is sucked and discharged by the hydraulic pump OP through the filter F, and its discharge pressure is adjusted by the relief valve 47, and then the oil is supplied to the pressure oil supply line 46. Pressure oil having a predetermined pressure is supplied.

The pressure oil supply line 46 is connected via a line 48 to a lockup five-way valve 49 for switching the pressure oil to the fluid coupling 2 to control the connection / disconnection of the lockup clutch 7. A pressure oil return line 50 for returning pressure oil to the oil tank 45 is connected to the lockup five-way valve 49, and a throttle valve 51, a cooler 52, and an opening / closing valve 53 are connected to the pressure oil return line 50. It

The on-off valve 53 is normally closed and the pressure oil supply line 4
6 is opened by the pressure oil from the pilot line 54 connected to 6.

The lockup five-way valve 49 is connected to the pilot line 55 of the pressure oil supply line 46 and is switched by a pilot control three-way solenoid valve 56 which is duty-controlled by the electronic control unit 22. Normally, the pilot control three-way solenoid valve 56 is OFF (as shown in the figure, oil is supplied from the lock-up five-way valve 49 to the oil tank 4).
5, the pressure oil from the line 48 flows from the line 57 to the outer chamber 34 through the inner passage 36 described in FIG. 2, and further to the turbine unit 5 and the pump unit 4. After that, the oil is returned from the outer passage 37 to the pressure oil return line 50 through the line 58 and the lock-up five-way valve 49. Therefore, the lockup clutch 7 is disengaged.

Three-way solenoid valve 56 for pilot control is ON
When the oil is supplied to the lock-up five-way valve 49 in the open state, the lock-up five-way valve 49 is switched by the pressure oil from the pilot line 55, and the pressure oil from the line 48 changes to the line 58. After flowing into the outer passage 37 and passing through the pump portion 4 and the turbine portion 5, it is enclosed in the inner chamber 35 and presses the clutch disc 31 against the casing 18. On the other hand, the oil in the outer chamber 34 is pushed out to the line 57, and the oil return line 6 is passed through the lock-up five-way valve 49.
It is returned from 0 to the oil tank 45. Therefore, the lockup clutch 7 is in contact.

The wet multi-plate clutch 3 is connected to the pressure oil supply line 46 through a line 68, and the line 6
8, a clutch switching three-way valve 61 is connected, the clutch switching three-way valve 61 is connected to a pilot line 62 of the pressure oil supply line 46, and the pilot control three-way solenoid valve 63 is duty-controlled by the electronic control unit 22.
You can switch with.

The pilot control three-way solenoid valve 63 is turned on.
(Oil from the clutch switching three-way valve 61 to the oil tank 45
The clutch switching three-way valve 61 is closed to discharge oil from the clutch 3 to the oil tank 45, and the clutch 3 is disengaged by the urging force of the spring 42.

The three-way solenoid valve 63 for pilot control is OFF
(When the oil is supplied from the pilot line 62 to the clutch switching three-way valve 61 as shown in the figure),
The clutch switching three-way valve 61 is opened to supply oil to the clutch 3, and the wet multi-plate clutch 3 is operated in the contact direction.

During operation of the engine E, the oil pump O is constantly operated.
Pressure oil is supplied to the pressure oil supply line 46 by P, and the pilot control three-way solenoid valve 56 and the pilot control three-way solenoid valve 6 are supplied by an electric signal from the electronic control unit 22.
The lock-up clutch 7 and the wet multi-plate clutch 3 are appropriately connected / disconnected and controlled by turning ON / OFF the switch 3.

When the engine E is stopped, the pilot control three-way solenoid valves 56 and 63 are turned off and the oil pump OP is stopped. Therefore, the lockup clutch 7 is disengaged. On the other hand, the clutch 3 is in an open state in which the clutch switching three-way valve 61 supplies pressure oil to the clutch 3, but since the oil pump OP is stopped, pressure oil is not supplied to the wet multi-plate clutch 3, resulting in Will be cut off. Thus, in this embodiment, when the engine E is stopped, the fluid coupling 2, the lockup clutch 7, and the wet multi-plate clutch 3 are all disengaged. However, the present invention can be applied to a vehicle in which only the wet multi-plate clutch 3 is disengaged or only the lockup clutch 7 and the fluid coupling 2 are disengaged when the engine E is stopped. That is, the "clutch mechanism that is automatically disengaged when the engine is stopped" described in claim 1 means all clutch mechanisms in which slip occurs between the engine E and the drive wheels when the engine E is stopped. is doing.

In this power transmission device, the power of the engine E is transmitted in the order of the fluid coupling 2, the wet multi-plate clutch 3, and the transmission T / M.

The control when the vehicle starts is as follows.

When the vehicle is in a gear-neutral state, the driver tries to start the vehicle and tries to operate the shift lever to the starting stage. Then, in the shift lever, the knob switch 20 is turned on by swinging the shift knob prior to the operation of the lever, and the clutch 3 is disengaged with this as a signal. When the shift lever is subsequently operated, the transmission T / M is geared to the start stage, and when this is detected by the gear-in detection means 21s, the clutch 3 is engaged. By this connection, the turbine portion 5 is stopped by the brake from the drive wheel side, so that the pump portion 4 slides with respect to the turbine portion 5 and a creep force is generated. Therefore, after that, when the brake pedal 25 is released or the accelerator pedal 23 is depressed, the vehicle starts moving. This point is the same as a normal AT car.

After the start, when the speed exceeds a predetermined speed, the lockup clutch 7 is brought into contact with the pump portion 4 and the turbine portion 5 of the fluid coupling 2 to rotate integrally.

Next, the operation during gear shifting while the vehicle is traveling will be described. It is assumed that the driver attempts to shift gears while operating the shift lever 21 while the vehicle is traveling at a predetermined gear. Then, prior to the operation of the lever, the shift knob swings, the knob switch 20 is turned on, and the clutch 3 is disengaged with this signal. Then, by continuously operating the shift lever 21, the transmission T / M is geared in to the next shift stage, and when this is detected by the gear-in detection means 21s, the clutch 3 is engaged. This completes a series of shift operations. Such clutch engagement / disengagement control is executed at each shift, and thus the driver can perform the shift operation without performing the clutch operation. During this shift, the lockup clutch 7 remains in the contact state, and the engine power is transmitted to the clutch 3 as it is.

As shown in FIGS. 1 and 2, the gear-in parking brake 70 combined with such a power transmission device has a brake drum 71 coaxially provided on the input shaft 8 of the transmission T / M. And a brake band 72 that is provided around the brake drum 71 so as to surround the brake drum 71, and a tightening mechanism 73 that reduces the diameter of the brake band 72 and tightens the brake drum 71.

The brake drum 71 is a cylindrical body which is integrally provided with the output side of the wet multi-plate clutch 3 spline-fitted to the input shaft 8 of the transmission T / M, and rotates integrally with the input shaft 8. It is like this.

The brake band 72 is made of a metal strip that is expandable and contractible. One end of the brake band 72 is provided with a bolt 75 on a mounting portion 74 provided on a partition wall 73 that separates the wet multi-plate clutch 3 from the transmission T / M. Are joined by. As shown in FIG. 2, the other end of the brake band 72 is located on the brake drum 71 in a free state, and an engaging projection 76 attached to the tip of the brake band 72 has a fastening mechanism described later. It is adapted to engage with the tip of the plunger 79 of 73.

The tightening mechanism 73 is a cylinder 77 attached to the clutch housing, a piston 78 slidably accommodated in the cylinder 77, and a piston 78 attached to the piston 78. It has a plunger 79 that engages with the engagement protrusion 76 of the band 72, and a coil spring 80 that biases the piston 78 and the plunger 79 toward the brake band 72 side in the cylinder 77. When the piston 78 moves toward the brake band 72, the plunger 79 projects in the tangential direction of the brake drum 71 and tightens the brake band 72 onto the brake drum 71, thereby restricting the rotation of the brake drum 71 and the input shaft 8 to apply a braking force. It is designed to give.

As shown in FIG. 4, the cylinder 77 of the tightening mechanism 73 has a line 8 connected to the pressure oil supply line 46.
1 is connected and pressure oil is constantly supplied into the cylinder 77 by the oil pump OP while the engine is operating, and the piston 78 is pushed back in the direction opposite to the brake band 72 facing the coil spring 80 by the pressure oil. . Therefore, the brake band 72 is the brake drum 71.
Since the clutch 3 is not tightened up and is in an inoperative state, power transmission from the clutch 3 to the transmission T / M is performed without loss.

On the other hand, when the engine is stopped from this state, the oil pump OP is stopped accordingly and the oil pressure in the pressure oil supply line 46 is lowered, so that the coil spring 8
The urging force of 0 causes the piston 78 to move to the brake band 72.
To the side, the brake band 72 moves to the brake drum 71.
It is tightened up and is in operation. Accordingly, the brake drum 71 and the transmission T that rotates integrally with the brake drum 71.
The rotation of the / M input shaft 8 is restricted. Therefore, the transmission T
If the engine is stopped while the / M gear is in any stage, rotation of the drive system on the downstream side of the clutch 3 is restricted even if the clutch 3 is disengaged, and gear-in parking is possible.

The relationship between the hydraulic pressure of the hydraulic circuit 19 and the stroke and braking force of the piston 78 will be described with reference to FIG.

In FIG. 5A, the vertical axis represents the piston stroke, and the brake band 72 increases toward the top.
Is approached (moved to the right side in FIG. 2). In FIG. 5B, the vertical axis represents the braking force that can be obtained.

As is clear from the figure, as the hydraulic pressure in the hydraulic circuit 19 decreases, the piston 78 moves toward the brake band 7
When it moves to the 2 side and reaches the hydraulic pressure p, it moves almost the entire stroke. However, at this time, the braking force is hardly obtained. When the hydraulic pressure further decreases, the force that opposes the coil spring 80 disappears, and the piston 78 and the plunger 79 sufficiently tighten the brake band 72 to obtain the braking force. Therefore,
In order to obtain sufficient braking force, the hydraulic pressure needs to drop to an extremely low level.

Therefore, the gist of the present invention is to provide a hydraulic pressure reduction promoting means in the hydraulic circuit 19 so that the hydraulic pressure is sufficiently reduced in a short time after the engine is stopped.

In this embodiment, the hydraulic pressure reduction promoting means is a valve means 101 composed of a clutch switching three-way valve 61 shown in FIG. 4 and a pilot control three-way solenoid valve 63 for switching the clutch switching three-way valve 61. And an electronic control unit 22 for opening and closing the pilot control three-way solenoid valve 63.

As described above, the pilot control three-way solenoid valve 63 is in the open state (OFF) for supplying the pilot switching hydraulic pressure to the clutch switching three-way valve 61, and when the clutch switching three-way valve 61 transfers oil to the oil tank 45 side. Closed state of discharging (O
N), and the electronic control unit 22
The duty is controlled by an electric signal given from the.

After the engine is stopped, an electronic signal is given from the electronic control unit 22 and the pilot control three-way solenoid valve 63 is duty-driven for a predetermined time to accelerate the reduction of the hydraulic pressure.

That is, when the pilot control three-way solenoid valve 63 is turned off (open state) after the engine is stopped, pressure oil is supplied from the pressure oil supply line 46 to the clutch switching three-way valve 61 through the line 62 (arrow). A). At this time, if the oil pressure in the pressure oil supply line 46 is not substantially reduced, the clutch switching three-way valve 61 is opened, and the pressure oil from the pressure oil supply line 46 passes through the line 68 and the wet multi-plate clutch 3 is opened. Flowing to the side.

Next, when the pilot control three-way solenoid valve 63 is turned on, the oil flowing through the clutch switching three-way valve 61 flows in the opposite direction and is discharged to the oil tank 45 (arrow B). Further, the clutch switching three-way valve 61 is closed, and the oil flowing in the wet multi-plate clutch 3 is discharged to the oil tank 45.

When the oil pressure in the pressure oil supply line 46 is lowered to some extent, the pilot control three-way solenoid valve 63 is turned off.
Even when F (open), the hydraulic pressure supplied to the clutch switching three-way valve 61 through the line 62 is low, and the clutch switching three-way valve 61 does not open. However, thereafter, the pilot control three-way solenoid valve 63 is turned on, so that the oil flowing through the clutch switching three-way valve 61 is discharged to the oil tank 45.

By repeating this at short intervals,
The oil in the pressure oil supply line 46 is successively introduced into the clutch switching three-way valve 61 and the wet multi-plate clutch 3 and discharged to the oil tank 45, so that the oil pressure in the hydraulic circuit 19 is significantly lowered in a short time. To do. Therefore, the braking force of the parking brake can be sufficiently obtained in a short time after the engine is stopped.

Next, a method of operating the hydraulic pressure reduction promoting means will be described with reference to FIG.
This will be described with reference to the flowchart shown in.

First, if the key is in the OFF state and the engine is stopped (START), it is determined in step 101 whether the gear of the transmission T / M is in any stage, that is, whether it is in the gear-in state. , Based on the input value from the gear-in detection means 21s. If not in the gear-in state, that is, in the neutral state, the process ends. This is because it is determined that the driver has no intention of performing gear-in parking.

If it is in the gear-in state, it is determined that the driver intends to park in the gear-in parking, and the step 10
At 2, the timer is set to 0. That is, this is to measure the time for which the pilot control three-way solenoid valve 63 is opened and closed.

When the timer setting is completed, the pilot control three-way solenoid valve 63 is set to 50 at step 103.
% Duty drive. That is, the ON / OFF operation of the pilot control three-way solenoid valve 63 is performed for the same period of time to intermittently discharge the hydraulic pressure of the pressure oil supply line 46 to the oil tank 45.

Next, at step 104, it is judged whether the elapsed time t after the timer setting is smaller than a preset tend (for example, 1 s). Elapsed time t
Is determined to be smaller than tend (t <tend), the process returns to step 103 and the pilot control three-way solenoid valve 63 is driven by 50% duty. That is, the opening / closing operation of the pilot control three-way solenoid valve 63 is performed when the elapsed time t is te
It is repeated until nd is reached.

In step 104, the elapsed time t is t
If it is determined that the value is equal to or more than end (t ≧ end), in step 105, the pilot control three-way solenoid valve 63 is driven by 0% duty, that is, turned off, and the process ends. At this time, the hydraulic pressure of the hydraulic circuit 19 is sufficiently reduced, and the gear-in parking brake 70 generates a large braking force.

As described above, according to this embodiment, the pilot control three-way solenoid valve 6 is operated for a predetermined time after the engine is stopped.
By opening and closing 3, the oil can be expelled to lower the hydraulic pressure in a short time, and the parking brake can obtain a sufficient braking force in a short time.

In the present embodiment, the valve means 101
Has been described as the pilot control three-way solenoid valve 63 and the clutch switching three-way valve 61, but the present invention is not limited in this respect, and the lockup five-way valve 49 and the pilot control three-way solenoid valve for switching it. The valve 56 may be used as a valve means to drive the pilot control three-way electromagnetic valve 56 for a predetermined period of time after the engine is stopped.
Also, a valve means for discharging oil may be separately provided.

Further, although the gear-in parking brake 70 is described as a drum type in the present embodiment, it is needless to say that it can be applied to other types of parking brakes such as a disc type.

[0076]

In summary, according to the present invention, an excellent effect that a sufficient braking force can be obtained in a short period of time after the engine is stopped is exhibited.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a power transmission device and a gear-in parking brake according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a gear-in parking brake according to an embodiment of the present invention.

FIG. 3 is a skeleton diagram showing a power transmission device according to an embodiment of the present invention.

FIG. 4 is a detailed view of a hydraulic circuit.

FIG. 5A is a diagram showing a relationship between a hydraulic pressure of a hydraulic circuit and a piston stroke. (B) is a figure which shows the relationship between the hydraulic pressure of a hydraulic circuit, and braking force.

FIG. 6 is a flowchart showing an operating method of the gear-in parking brake according to the embodiment of the present invention.

[Explanation of symbols]

1 Clutch mechanism 2 fluid coupling 3 Friction type shift clutch 7 Lockup clutch 19 Hydraulic circuit 22 Electronic control unit 49 Five-way valve for lock-up 61 Three-way valve for clutch switching 63 Oil pressure drop promoting means 70 Gear-in parking brake 71 brake drum 72 brake band 78 pistons 79 Plunger 80 coil spring

Continued front page    F-term (reference) 3D041 AA65 AB01 AC09 AC26 AC30                       AD02 AD10 AD22 AD23 AD31                       AD41 AD51 AE14 AE42                 3D046 AA05 BB02 EE00 GG06 HH02                       HH05 HH07 HH17 HH22 KK11                       LL23

Claims (4)

[Claims] 1. A power transmission device provided with a clutch mechanism that is interposed between an engine and a transmission and is automatically disengaged when the engine is stopped, and operates when the engine is stopped in a gear-in state. A control device for a gear-in parking brake, comprising a hydraulic circuit including an oil pump that supplies pressure oil to control the operation / non-operation of the clutch mechanism and the gear-in parking brake, wherein the gear-in parking brake is When the engine is in operation, pressure oil is constantly supplied from the hydraulic circuit to bring it into a non-operating state, and when the engine is stopped, the oil pump stops and the hydraulic pressure in the hydraulic circuit drops, so that the hydraulic circuit is activated. The circuit further includes a hydraulic pressure reduction promoting means for reducing the hydraulic pressure in a short time after the engine is stopped. Parking brake control device. 2. The clutch mechanism comprises a fluid coupling connected to an output shaft of an engine, a lock-up clutch for mechanically connecting and disconnecting an input / output side of the fluid coupling, and the fluid coupling and the transmission. A friction type speed change clutch provided, wherein the hydraulic pressure reduction promoting means is in an open state in which pressure oil is supplied to the lockup clutch or the friction type speed change clutch;
It consists of valve means for switching to a closed state where pressure oil is discharged to the oil tank side from the lockup clutch or the friction type shift clutch, and an electronic control unit for opening and closing the valve means for a predetermined time after stopping the engine in the gear-in state. The control device for the gear-in parking brake according to claim 1. 3. The clutch for switching the valve means between an open state in which pressure oil is supplied to the friction type speed change clutch and a closed state in which pressure oil is discharged from the friction type speed change clutch according to the applied pilot oil pressure. A switching valve, and a pilot solenoid valve that switches between an open state in which pilot hydraulic pressure is supplied to the clutch switching valve in response to an applied electric signal and a closed state in which oil is discharged from the clutch switching valve. The gear-in parking brake control device according to claim 2, wherein the electronic control unit opens and closes the pilot solenoid valve for a predetermined time after the engine is stopped in the gear-in state. 4. The control device for a gear-in parking brake according to claim 1, wherein the gear-in parking brake is provided on an input shaft of the transmission.