JPH0254258B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a brake device for a vehicle, and is particularly suitable for a vehicle having an electric brake such as an air brake or a regenerative brake, and which performs automatic driving. This relates to a brake device.

[Background of the invention]

A conventional brake device for a vehicle will be explained with reference to FIG. FIG. 1 is a circuit diagram showing a control system of a conventional brake device. In the figure, when operating the brake, first the brake command device 7
from the brake command device 7 to the chopper control device 2 which operates the plurality of brake electromagnetic valves 1a for air brake control constituting the relay valve 1 and operates the regenerative brake which is an electric brake. Output a control signal to operate. The brake commands from the brake command device 7 are in stages, and the brake solenoid valves 1a are configured to control the combined braking force according to the output stages of the brake commands. There is. Further, the plurality of brake electromagnetic valves 1 are given an output from a load adjustment device 5 that detects the occupancy rate of the vehicle and outputs a signal corresponding to the occupancy rate of the vehicle, and a control signal from the brake command device 7 and a corresponding signal are given to the brake solenoid valves 1. Adjustable load device 5
The amount of compressed air supplied from the air reservoir 6 to the air brake cylinder 8 is controlled by a control signal from the air reservoir 6. On the other hand, the control signal (stepwise control output) from the brake command device 7 is converted by a converter 2d,
The output is input to the chopper control circuit 2b via the variable load actuator 2c that reflects the occupancy rate. The chopper control circuit 2b outputs an output corresponding to the control input to the main motor 3.
Braking is performed by the regenerative action of The main circuit current corresponding to the braking force during the braking operation of the main motor 3 is detected by the brake torque detector 2a, converted into air pressure by the electropneumatic control device 4, and output. By the way, in the relay valve 1, the output (+) from the brake solenoid valve 1a and the output (-) output from the brake torque detector 2a via the electro-pneumatic control device 4 are sent to the respective membrane chambers 1b. and add the respective outputs,
When the regenerative braking force from the main electric motor 3 is large, the amount of compressed air supplied from the air reservoir 6 to the air brake cylinder 8 is controlled by the valve mechanism, and when the regenerative braking force is small, the air brake cylinder 8 The structure is designed to increase the amount of compressed air supplied to the The brake solenoid valve 1a' has the same construction as the brake solenoid valve 1a, but is operated in the event of an emergency stop and operates the air brake regardless of regenerative braking force.
The calculation in the relay valve 1 is expressed by the following equation.

(Brake command value) - (Regenerative braking force) = (Supplementary braking force) The supplementary braking force is the braking force obtained by the air brake cylinder 8. This supplementary braking force compensates for the lack of braking force of the regenerative braking by the main electric motor 3, and cooperative control of the air brake and regenerative braking is performed.

In such a configuration, as mentioned above, the load adjustment device 5 adjusts the occupancy rate to obtain a constant deceleration. It cannot compensate for changes in frictional characteristics and decreases in the efficiency of the air-oil converter at low speeds, and has drawbacks such as lowering the accuracy of fixed-point stopping during automatic operation and causing a predetermined stopping range.

[Purpose of the invention]

An object of the present invention is to provide a brake device for a vehicle that can accurately stop at a fixed point during automatic driving.

[Summary of the invention]

In order to improve fixed-point stopping accuracy and passenger comfort during automatic vehicle operation,
The problem is how to reduce variations in deceleration when the vehicle is running. The main reason for the variation in deceleration is largely due to the variation in the friction coefficient of the brake lining, and the factors for variation in this friction coefficient include speed and load conditions. Variations in the load conditions can be adjusted by a variable load device, which has been conventionally done. Therefore, the present invention is characterized in that speed conditions, which are another variable factor, are reflected in brake control to prevent variations in deceleration.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. In the figure, the same reference numerals as in the conventional example refer to the same members. 10 is a brake initial speed detector that detects the initial speed when the brake is applied, and 11 is an amplifier that amplifies the signal current of the detection result that is the output of the brake initial speed detector 10. Reference numeral 12 denotes a speed control valve that pushes down a valve body with an electromagnetic force proportional to the output signal current from the brake initial speed detector 10, adjusts the internal pressure of the air spring 9 that supports the vehicle body, and transmits it to the variable load device 5. Reference numeral 13 denotes an auxiliary command device that operates only when braking is commanded in a low speed range, and 14 opens and closes a valve according to a command from the auxiliary command device 13 to control the air pressure transmitted from the air spring 9 to the variable load device 5. This is an auxiliary control valve that increases pressure. Note that 15 is a check valve provided at a position where the air pressure from the auxiliary control valve 14 is applied to the piping of the air spring 9.

In such a configuration, when a brake command is now output from the brake command device 7, the vehicle speed at this point is detected by the brake initial speed detector 10, and the speed control valve 12 is detected via the amplifier 11.
is output to. With this input, the speed control valve 1
2 suppresses the internal pressure of the air spring 9 as the input speed becomes low, and transmits it to the variable load device 5 without suppressing it when the input speed is high. Further, in the low speed range, the auxiliary command device 13 operates, and the auxiliary control valve 14 increases the internal pressure of the air spring 9 and transmits it to the variable load device 5.

In this way, according to this configuration, it is possible to apply a braking force according to the initial brake speed by following the change in the friction coefficient of the brake lining, and it is possible to improve fixed-point stopping accuracy during automatic driving and improve safety. It can also be improved. Moreover, it can be made to work effectively even when efficiency decreases in a low speed range.

〔Effect of the invention〕

As explained above, according to the present invention, the braking force can be adjusted according to the speed of the vehicle to keep the deceleration constant in response to changes in brake friction characteristics.
Fixed point stopping performance can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a control system of a conventional brake device, and FIG. 2 is a circuit diagram showing a control system of an embodiment of a brake device according to the present invention. 1...Relay valve, 2...Chipper control device, 3...
...Electric motor, 4...Electro-pneumatic control device, 5...Load adjustment device, 6...Air reservoir, 7...Brake command device, 8
...Air brake cylinder, 9...Air spring,
10...Brake initial speed detector, 11...Amplifier, 12...Speed control valve, 13...Auxiliary command device, 14...Auxiliary control valve.

Claims (1)

[Claims] 1. Regenerative braking means, a relay valve that controls air braking force by subtracting the braking force by the regenerative braking means, air braking means controlled by the relay valve, and brakes of the regenerative braking means and the air braking means. In a vehicle brake system comprising a variable load device that controls force according to the occupancy rate, a brake initial speed detector is provided to detect the initial speed when the brake is applied, and the variable load device is provided with a brake initial speed detector. 1. A vehicle brake device comprising a speed control valve that suppresses pressure applied from an air spring as a detected value becomes lower.