JPH0512183B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a slope start assisting device for a vehicle to facilitate slope start, and particularly to control of release timing of retained hydraulic pressure during slope start.

(Prior Art) As a conventional slope start assist device, for example, one described in Japanese Utility Model Application Publication No. 75162/1983 is known.

This conventional device includes an accelerator switch that detects an accelerator operation for starting the vehicle, a vehicle tilt sensor that detects the tilt of the vehicle in the direction of travel, and an engine rotation speed detection sensor. On a substantially flat road, the brake lock is released when the accelerator is operated, and when the vehicle lean angle is greater than a predetermined value, release of the brake lock is delayed until the engine speed reaches a predetermined value.

(Problems to be Solved by the Invention) However, in such conventional devices, the release timing is controlled by the engine speed, so when the clutch is in the released state or in the initial state of engagement, In some cases, the engine speed increases due to engine revving, etc., and the retained fluid pressure is released, making it impossible to obtain sufficient starting torque and causing the vehicle to move backwards, or when the clutch is not fully engaged. In this case, there is a problem in that when the engine reaches a predetermined rotational speed at which the retained hydraulic pressure is released, the starting torque becomes too high, resulting in a sudden start.

Furthermore, when the clutch wears out, the clutch engagement position changes, so there is a problem in that the release timing must be adjusted in accordance with the change in the engagement position.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and in order to achieve this purpose, the present invention employs the following solving means. did.

The solution of the present invention will be explained with reference to the conceptual diagram of the claim shown in FIG. Brake pedal 1 is provided when stopping on a slope.
When a signal indicating a predetermined starting state is inputted from the hydraulic pressure holding valve 5, which holds the brake fluid pressure even when the driver is released, and releases the brake fluid pressure when starting on a slope, and the input sensor 6, the valve actuator 7
and a release timing control means 8 for outputting a release signal c for releasing the retained hydraulic pressure. A first switch 601 and a second switch 602, both of which output an OFF signal when the friction member 901 and the vehicle body side member 902 are neutral, are provided on the vehicle body side member 902 facing the vehicle body side member 902, and the release timing control means 8 is applied to the wheel. From ON indicating that the friction member 901 is moving from one position of the vehicle body side member 902 to the neutral position due to the driving torque.
When the signal changes to OFF, the first switch 601 and the second
The means is configured to output a release signal n when input from any of the switches 602.

(Function) Therefore, in the slope start assisting device of the present invention, as described above, when the driving torque applied to the wheels at the time of slope start is balanced with the torque obtained by adding the braking torque and the load torque due to the slope road surface, the friction member The friction member is moved from one position to the neutral position by either the first switch or the second switch provided on the vehicle body side member of the brake device, taking advantage of the fact that the friction member moves as the driving torque increases. show
By using a means to release the hydraulic pressure retention by outputting a release signal when a signal change from ON to OFF is input, the retention hydraulic pressure is released when the drive torque required for starting is reached, and when starting It is possible to ensure a smooth start on a slope without the need for the vehicle to back up or start suddenly.

Moreover, as a switch, the friction member of the brake device is placed on both sides of the friction member and the vehicle body side member opposite in the direction of rotation, when the friction member and the vehicle body side member are neutral.
Since the first and second switches are provided to output an OFF signal, the ON signal can be output from the ON signal regardless of whether you are starting from the front on an uphill or downhill slope, or when starting from the rear on an uphill or downhill slope. The brake fluid pressure can be released at the optimal timing through simple control that simply monitors one switch signal that changes to the OFF signal.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.
In describing this embodiment, an example will be taken of a slope start assist device used in a vehicle such as a passenger car.

First, the configuration of the first embodiment will be explained.

As shown in FIG. 2, the hill start assist device A of the first embodiment includes a brake pedal 10, a booster 1
1. Tandem master cylinder 12, primary side brake hydraulic piping system 13, secondary side brake hydraulic piping system 14, front wheel cylinder 1
5, 16, rear wheel cylinders 17, 18, a hydraulic pressure holding valve 19, an input sensor 20, and a control unit 21. Each configuration will be described in detail below.

A brake pedal 10 is connected to a valve operating rod of a booster 11.

The booster 11 is a booster that increases the brake pedal force applied to the brake pedal 10 by using engine negative pressure, etc. The brake pedal force increased by the booster 11 is applied to the primary piston of the tandem master cylinder 12 and applied to a secondary piston (not shown).

The tandem master cylinder 12 converts the brake pedal force from the booster 11 into brake fluid pressure, and the tandem master cylinder 12 is formed with two independent fluid pressure generating chambers corresponding to a primary piston and a secondary piston. ing.

The primary brake hydraulic piping system 13 is a piping system that supplies brake hydraulic pressure from the primary hydraulic port 22 of the tandem master cylinder 12 to the front wheel cylinders 15 and 16.

The secondary brake hydraulic piping system 14 is a piping system that supplies the brake hydraulic pressure from the secondary hydraulic port 23 of the tandem master cylinder 12 to the rear wheel cylinders 17 and 18. A hydraulic pressure holding valve 19 is provided.

In addition, the secondary side brake hydraulic piping system 14 is as follows:
It is composed of a master cylinder side brake pipe 141 and a wheel cylinder side brake pipe 142.

The front wheel cylinders 15, 16 and the rear wheel cylinders 17, 18 operate a brake device such as a drum brake or a disc brake.The rear wheel cylinders 17, 18 operate a disc brake 40, which will be described later, and the braking force is It is proportional to the magnitude of brake fluid pressure.

The hydraulic pressure holding valve 19 is provided in the middle of the secondary brake hydraulic piping system 22, and maintains the current brake hydraulic pressure even when you take your foot off the brake pedal 10 when stopping on a slope, and maintains the brake hydraulic pressure when starting on a slope. This is a valve that releases the holding, and as shown in Fig. 3, the valve body 24 and the input port 2
5, an output port 26, a plunger chamber 27, a ball chamber 28, a ball valve 29, a valve seat 30, a plunger 31, a plunger spring 32, and a solenoid (valve actuator) 33.

The hydraulic pressure holding valve 19 is constituted by a ball valve 29 and a valve seat 30, and in the valve open state where the ball valve 29 is prevented from seating on the valve seat 30 by the biasing force of the plunger spring 32. , master cylinder hydraulic pressure Pm is,
Input port 25 → plunger chamber 27 → ball chamber 2
8 -> output port 26 and is supplied directly to the rear wheel cylinders 17 and 18.

Note that when the control unit 21 outputs the energization signal i to the solenoid 33, the plunger 31 moves downward in the drawing against the plunger spring 32, and the ball valve 29 moves toward the valve seat 30.
The master cylinder hydraulic pressure Pm when the valve is closed is maintained in the wheel cylinder side brake pipe 142 and the rear wheel cylinders 17 and 18.

The input sensor 20 is provided to obtain input signals for hydraulic pressure holding timing control for holding brake hydraulic pressure and release timing control for releasing brake hydraulic pressure holding.
Vehicle speed sensor 201, clutch sensor 202, shift position sensor 203, parking brake switch 204, first switch 205, second switch 2
It is equipped with 06.

The vehicle speed sensor 201 is a sensor that detects vehicle speed and outputs a vehicle speed signal v.

The clutch sensor 202 is a sensor that detects whether the clutch is in a fastened state or a released state and outputs a clutch signal k.

The shift position sensor 203 is a sensor that detects the shift position of the transmission and outputs a shift position signal p.

The parking brake switch 204 is a switch that detects whether the parking brake is activated or not and outputs a parking brake signal b.

First switch 205 and second switch 206
is the torque member 401 (corresponding to the vehicle body side member) of the disc brake 40 (corresponding to the brake device)
and outer pad 402 or inner pad 4
03 (corresponding to the friction member), and at an opposing position in the disc rotor rotation direction D (torque member 4
01 side), and both switches 2
05, 206, as shown in FIG. 5, the disc rotor 3 on the wheel 34 side is
The outer pad 402 and inner pad 403 that are in pressure contact with the torque member 40 on the vehicle body side
The switch is connected/disconnected by moving from the neutral position with respect to 1, and when both pads 402, 403 are moved, ON signal 01 or 02 is output from one of the switches 205, 206 on the moving side, and , when neutral, both switches 205,2
ON signals 01 and 02 are not outputted from any of 06.

Incidentally, the disc brake 40 of the embodiment is a single cylinder. 1 piston. It is a floating caliper type and has a torque member 40 as shown in Figure 4.
1. Outer pad 402, inner pad 40
3. Padded spring 404, outer shim 40
5. Inner shim 406, piston cover shim 4
07, lock pin 408, guide pin 409, lock pin boot 410, guide pin boot 41
1. Cylinder body 412, air bleeder 41
3, a piston seal 414, a piston 415, a dust cover 416, and a retainer ring 417.

The control unit 21 outputs an energization signal i to the solenoid 33 when a signal indicating a predetermined slope stop state is input from the input sensor 20, and a signal indicating a predetermined start state is input from the input sensor 20. When the third
As shown in the figure, an A-D conversion circuit 211, a RAM
(Random.Access.Memory) 212, ROM
An on-vehicle microcomputer is used, which includes a read-only memory (read-only memory) 213, a CPU (central processing unit) 214, a clock circuit 215, and a control signal generation circuit 216.

The A-D conversion circuit 211 converts the analog input signal from the input sensor 20 into the CPU 214.
This is a circuit that converts signals into digital signals that can be processed using .

The RAM 212 is a memory that can be written to and read from, and is used to temporarily write input signals until the CPU 214 has time to process the calculations, or to temporarily write necessary information during the calculation process.

ROM213 is a read-only memory.
Information necessary for arithmetic processing by the CPU 214 is stored in advance.

The CPU 214 is called a central processing unit, and reads information from the RAM 212 and ROM 213 as necessary, processes the information according to a predetermined arithmetic processing procedure, and outputs the result signal to the control signal generation circuit 216. This is a circuit that does this.

The clock circuit 215 is a circuit that sets the calculation processing time of the CPU 214.

The control signal generation circuit 216 is a circuit that outputs an energization signal i and a energization release signal n as control signals based on a result signal from the CPU 214.

Next, the operation of the first embodiment will be explained.

(a) Hydraulic pressure holding timing control Hydraulic pressure holding timing control of the brake hydraulic pressure in the control unit 21 is performed according to the flow of control operations as shown in the flowchart of FIG.

In step 100, the vehicle speed signal v from the vehicle speed sensor 201, the clutch signal k from the clutch sensor 202, the shift position signal p from the shift position sensor 203, and the parking brake switch 204 are
Parking brake signal b from .

In step 101, it is determined whether the vehicle speed signal v read in step 100 is a signal indicating that the vehicle speed is zero, and the vehicle speed is determined to be zero (stopped state).
If it is determined that the vehicle speed is not zero (running state), proceed to the next step 102.
Return to 100.

In step 102, it is determined whether the clutch signal k read in step 100 is a signal indicating a clutch release or a signal indicating a clutch engagement.If it is determined that the clutch is in an open state, the process proceeds to the next step 103, in which the clutch is closed. If it is determined that the system is in the fastened state, the process returns to step 100.

In step 103, based on the shift position signal p read in step 100, it is determined whether the shift position is a signal indicating the 1st gear position or reverse position, or a signal indicating another shift position, and whether the shift position is the 1st gear position or the reverse position is determined. If it is determined that this is the case, the process proceeds to the next step 103, and if it is determined that it is any other forward position, the process returns to step 100.

In step 104, it is determined whether the parking brake is activated or not, based on the parking brake signal b read in step 100. If the signal indicates that the parking brake is not activated, the process advances to the next step 104. , when the signal indicates operation, the process returns to step 100.

In step 105, the condition that the vehicle is stopped on a slope and the brake fluid pressure must be maintained is set in the step 105.
It is determined that the condition is satisfied after 101, 102, 103, and 104, and an energization signal i is output from the control unit 21 to the solenoid 33 of the hydraulic pressure holding valve 19.

Due to this flow of operation, when the energization signal i is output to the solenoid, the plunger 31 of the hydraulic pressure holding valve 19 is forcibly moved downward in the drawing by electromagnetic force against the plunger spring 32. At the same time, the ball valve 29 is seated on the valve seat 30, so that the master cylinder hydraulic pressure Pm from the tandem master cylinder 12 is reduced when the ball valve 29 is seated.
is maintained, and even after the brake pedal 10 is released, the hydraulic pressure is maintained.

Note that the energization signal i to the solenoid 33 remains output unless a predetermined release condition is satisfied in the release timing control described below.

In addition, when trying to increase the retained fluid pressure, by depressing the brake pedal 10 again and sending the master cylinder hydraulic pressure Pm higher than the retained fluid pressure, the ball valve 29 is temporarily separated from the valve seat 30 and the retained fluid is increased. pressure can be increased.

(b) Release Timing Control The release timing control for releasing the brake fluid pressure held by the control unit 21 is carried out according to the flow of control operations as shown in the flowchart of FIG.

In step 106, the ON signal 01 or 0 from the first switch 205 or the second switch 206 is
2 is loaded.

In step 107, it is determined whether the ON signal 01 or 02 read in step 106 has changed to an OFF signal, and as long as there is no change to OFF and one ON signal is output, the step continues.
Steps 106 and 107 are repeated, and when the signal changes to OFF, the process advances to the next step 108.

In step 108, the control unit 21
The deenergization signal n is output from the solenoid 33 of the hydraulic pressure holding valve 19. Due to this flow of operation, the solenoid 33
When the energization release signal n is output to
It is pulled away from 0, the retained hydraulic pressure is released to the tandem master cylinder 12 side, and the hydraulic pressure maintained state is released.

As described above, in the first embodiment, as shown in FIG. 5, the driving torque T ₀ applied to the wheels 34 when starting on a slope is the sum of the braking torque T ₁ and the backward torque T ₂ due to the slope road surface R. When balanced, the outer pad 402 (inner pad 4
03) starts moving in the driving torque T ₀ direction with the disc rotor 35, and the torque member 401
The first switch 205 and the second switch 20 provided in
When a signal indicating that the outer pad 402 (inner pad 403) is in the neutral position is input from 6 (ON signal → OFF signal), the hydraulic pressure retention is released, so the release timing becomes the engine torque required for starting. When the vehicle is started, it is possible to start smoothly on a slope without causing the vehicle to back up due to insufficient torque or to start suddenly due to excessive torque.

Furthermore, in the disc brake 40 portion of the wheel 34, the driving torque T ₀ , braking torque T ₁ and reverse torque T ₂ are detected and the release timing is controlled, which affects the starting torque when starting on a slope. The release timing can be set in accordance with all of the factors that give rise to the problem, such as the slope angle, road surface friction coefficient, and vehicle weight.

In other words, in controlling the release timing of hydraulic pressure maintenance, a driving torque sensor, a braking torque sensor, and sensors that detect various road surface conditions and vehicle conditions are used.
The disc brake 4 has the same function of controlling release timing using complex control conditions.
The first switch 205 and the second switch 2 provided at
06, and the configuration of sensors and controls can be extremely simplified.

Furthermore, in the first embodiment, an ON signal is input from either the first switch or the second switch when driving uphill or downhill, and the hydraulic pressure is maintained and released even when reversing. By that,
It can also handle starting in reverse from a downhill slope.

Next, a second embodiment shown in FIG. 8 will be described.

This embodiment is an example in which hydraulic pressure holding valves 19' corresponding to two systems of brake hydraulic piping are used.

The hydraulic pressure holding valve 19' of the second embodiment includes a valve body 50, a first hydraulic pressure input port 51, a first input chamber 52, a first piston 53, a piston spring 54, a first valve 55, and a first valve spring 5.
6, first valve seat 57, first valve chamber 58,
First hydraulic pressure output port 59, stepped piston 60, piston spring 61, second hydraulic pressure input port 6
2, a second piston 63, a second valve 64, a second valve spring 65, a second valve seat 66, a second valve chamber 67, a second hydraulic output port 68, and a solenoid 69.

Note that the first hydraulic pressure input port 51 is pipe-connected to a primary side hydraulic pressure port of a tandem master cylinder (not shown), and the second hydraulic pressure input port 62 is pipe-connected to a secondary side hydraulic pressure port. .

Further, the first hydraulic pressure output port 59 is pipe-connected to the left front wheel cylinder and the right rear wheel cylinder, and the second hydraulic pressure output port 6
A pipe 8 is connected to the front wheel cylinder on the right wheel side and the rear wheel cylinder on the left wheel side, forming a so-called x pipe.

Note that a relief valve is formed by the first piston 53 and the piston spring 54, and the operation of the hydraulic pressure holding valve 19' other than that which specifies the maximum pressure of the holding liquid pressure is performed by the two valves in the first embodiment. As in the example, open and close the valve.

Furthermore, since the input sensor 20 and control unit 21 have the same configuration as the first embodiment,
A description of the control operation will be omitted.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, in the embodiment, the first switch and the second switch are provided on the torque member side of the disc brake, but both switches may be provided on the back metal part of the brake pad.

Further, each of the above embodiments shows an example in which a switch is applied to a disc brake, but the present invention is not limited to this. For example, in the case of a drum brake device, the rotational direction position of the brake shoe This can be easily applied if a switch is provided to detect this.

(Effects of the Invention) As explained above, in the hill start assisting device of the present invention, the friction member moves from one position of the vehicle body side member to the neutral position due to the driving torque applied to the wheels when starting on the slope. When a signal change from ON to OFF indicating that the switch is on, is input from either the first switch or the second switch, the hydraulic pressure retention is released by outputting the release signal. In the case of starting, also
In the case of starting backwards, both uphill and downhill,
By simply monitoring one switch signal that changes from an ON signal to an OFF signal, it is possible to release the brake fluid pressure at an optimal timing.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of claims showing the slope start assist device of the present invention, Fig. 2 is an overall view showing the slope start assist device of the first embodiment of the present invention, and Fig. 3 shows the main parts of the device of the first embodiment. 4 is a perspective view showing the disc brake of the device of the first embodiment, and FIG. 5 is an explanatory view of the operation of the device of the first embodiment showing the state of stopping on a slope.
FIG. 6 is a flowchart showing the flow of hydraulic pressure holding timing control in the control unit of the first embodiment, and FIG. 7 shows the flow of release timing control in the control unit of the first embodiment. The flowchart shown in FIG. 8 is a diagram showing the hydraulic pressure holding valve of the second embodiment device. 1... Brake pedal, 2... Master cylinder, 3
...Wheel cylinder, 4...Brake hydraulic piping system,
5...Liquid pressure holding valve, 6...Input sensor, 601...
Switch, 602... Switch, 7... Valve actuator, 8... Release timing control means, 9... Brake device, 901... Friction member, 902... Vehicle body side member, n... Release signal.

Claims (1)

[Scope of Claims] 1. The system is installed in the middle of a brake fluid pressure piping system that supplies fluid pressure from the master cylinder to the wheel cylinders in accordance with the pressing force on the brake pedal, and when stopped on a slope, the brake fluid pressure is maintained even if the brake pedal is released. A hydraulic pressure holding valve that holds the brake fluid pressure and releases it when starting on a slope, and a release signal that causes the valve actuator to release the held hydraulic pressure when a signal indicating a predetermined starting condition is input from the input sensor. and a release timing control means for outputting a signal, wherein the input sensor is connected to a vehicle body side member facing both sides of the friction member of the brake device in the rotational direction when the friction member and the vehicle body side member are neutral. sometimes both
A first switch and a second switch are provided that output an OFF signal, and the release timing control means is set to an ON state indicating that the friction member is moving from one position of the vehicle body side member to a neutral position due to the driving torque applied to the wheel.
1. A slope start assisting device, characterized in that the device outputs a release signal when a signal change from to OFF is input from either the first switch or the second switch.