JPS6216861B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electric vehicle control device that uses both an electric brake and a fluid brake, and detects whether the sum of both brake forces has reached a commanded brake force,
The present invention relates to a brake monitoring device that sends a signal to a monitoring circuit.

First, a conventional brake monitoring device for electric vehicles of this type will be explained with reference to FIG.

Operate brake controller 1 to connect three command lines
When a brake command is given to SB ₁ , SB ₂ , and SB ₃ , the solenoid valves 3 , 4 , and 5 of the brake control device 2 are deenergized in various combinations according to the command, and a variable load is supplied from the air reservoir (not shown) to the conduit 6 . The compressed air supplied to each electromagnetic valve 3, 4, 5 via the valve 7 and the pipe line 8 is sent from these electromagnetic valves 3, 4, 5 to each membrane of the duplex relay valve 12 through the pipe lines 9, 10, 11. Board chamber 12a ₁ , 12a ₂ ,
Sent to 12a ₃ . And this multiple relay valve 12
The compressed air whose pressure is controlled according to the command braking force is sent as a first fluid pressure to the chamber 14a1 of the auxiliary relay valve 14 via the pipe line ₁₃ , and is converted into an electric-hydraulic pressure conversion valve to be described later. The piston 16 is raised and lowered in accordance with the differential pressure between the _second fluid pressure sent from the output port 17 to the second fluid pressure, and the output pressure is sent to the brake cylinder (not shown) from the output port 17 to create a fluid brake (not shown). ).

Further, a part of the output pressure from the output port 17 is transferred to the membrane plate chamber 19a ₁ of the output switch 19 via the conduit 18.
transmitted to.

On the other hand, the electric-fluid pressure conversion valve 15 is an electromagnetic valve that converts the magnitude of current from a torque detector 20 connected to an electric brake device (not shown) into the magnitude of fluid pressure. It has a coil 20A, a membrane plate 15b, and a piston 21 connected to the iron core of the electromagnetic coil 20A.
The compressed air pressure supplied through the auxiliary relay valve 14 is converted into air pressure corresponding to the electric braking force, and the converted air pressure is sent to the membrane plate chamber 14a ₂ of the auxiliary relay valve 14 as a second fluid via the pipe line 23. A portion of the fluid pressure corresponding to this electric braking force is transmitted to the membrane plate chamber 19a ₂ of the pressure switch 19 via the conduit 23. Therefore, air equivalent to the electric brake is introduced into the lower membrane plate chamber 19a ₂ of the pressure switch 19, and the membrane plate 19b ₂
In addition, the fluid pressure of the brake cylinder is introduced into the upper membrane plate chamber 19a ₁ to push up the membrane plate 19b ₁ . As a result, the two fluid pressures are summed and cause the piston rod 24 to rise against the spring 25, closing the switch contact 27 of the monitor 26 when the total pressure reaches the value set by the spring 25. In this way, the pressure switch 19 detects whether the sum of the fluid pressure of the electric brake and the fluid pressure of the fluid brake satisfies a set value (spring force) or more. A signal was sent to the monitor 26 by turning it on or off.

According to such conventional monitoring devices, electrical,
It only detects whether the sum of both hydraulic brake forces is above a certain value, and has the disadvantage that it cannot determine whether or not the brake force corresponding to the brake command corresponding to the notch, which takes into account the variable load, is being generated. It was hot.

The present invention eliminates the drawbacks of the conventional devices described above and provides a brake monitoring device for electric vehicles that can reliably detect whether the sum of both electrical and hydraulic braking forces has reached the commanded braking force. The pressure switch has a membrane plate chamber into which the output pressure from the auxiliary relay valve and the second fluid pressure from the electric-hydraulic pressure conversion valve are introduced, and a membrane plate chamber facing the membrane plate chamber. A membrane plate chamber into which a first fluid pressure controlled to a pressure corresponding to the commanded braking force is introduced from the arranged dual relay valve, and a switch connected to the movable part of the membrane plate forming these membrane plate chambers and at the connecting end. A piston rod having a contact point is provided.

The present invention will be explained below with reference to an embodiment shown in FIG. Note that the same components as those of the conventional device described above are denoted by the same reference numerals in the drawings, and the explanation thereof will be omitted. The present invention provides a membrane plate 19 that contributes to the lifting and lowering of the piston rod 24 in addition to the conventional pressure switch 19.
b ₃ and a membrane plate chamber 19a ₃ are added, and a part of the output fluid pressure of the dual relay valve 12 is transferred to the membrane plate chamber 19a ₃ through the pipe line 13.
It is designed to be guided through a conduit 28 branched from.

According to this configuration, the piston rod 24 of the pressure switch 19 receives the fluid pressure P ₁ inside the brake cylinder and the fluid pressure P corresponding to the electric brake force converted into fluid pressure by the electric-fluid pressure conversion valve 15. ₂ , the sum of the output fluid pressure P ₀ of the duplex relay valve 12, which is the brake command pressure obtained by adding the variable load to the notch command, and the force F _S of the spring 24 acts differentially. That is, if the force acting upward on the piston rod 24 is assumed to be positive, the force P acting on the piston rod is P=P ₁ +P ₂ −(P ₀ ×α+F _S ). Here, α=area of membrane plate (19b ₃ )/area of membrane plate (19b ₁ ).

Therefore, by appropriately setting α and the spring force F _S , the switch contact 27 can cause the sum of the fluid pressure of the electric brake and the fluid pressure of the fluid brake to exceed the fluid pressure of the command brake. It constantly detects whether it is satisfied and sends a signal to the monitor 26.

As described above, according to the present invention, the dual type is operated by compressed air supplied via a solenoid valve and sends out compressed air controlled to a pressure corresponding to a commanded braking force as the first fluid pressure. a relay valve, an electric-fluid pressure conversion valve that converts the electric brake force into a corresponding fluid pressure and sends it out as a second fluid pressure, and subtracts the second fluid pressure from the first fluid pressure. an auxiliary relay valve that supplies the fluid pressure as an output pressure to the fluid brake;
a pressure switch for detecting whether the total pressure of the output pressure and the second fluid pressure is greater than or equal to the first fluid pressure; and a membrane plate chamber which is arranged opposite to the membrane plate chamber and into which the first fluid pressure is introduced, and a piston rod which is connected to the movable part of the membrane plate forming these membrane plate chambers and has a switch contact at the connecting end. With this structure, it is possible to accurately monitor the braking force of an electric vehicle using both electric and fluid, which has the effect of significantly improving reliability and safety.

[Brief explanation of the drawing]

FIG. 1 is a fluid circuit diagram showing a conventional brake monitoring device for electric vehicles, and FIG. 2 is a fluid circuit diagram showing an embodiment of the brake monitoring device for electric vehicles according to the present invention. 1: Brake device, 2: Brake control device,
3, 4, 5: Solenoid valve, 7: Adjustable load valve, 12: Dual relay valve, 14: Auxiliary relay valve, 15: Electrical-fluid pressure conversion valve, 19: Pressure switch, 19a ₁ , 19a ₂ ,
19a ₃ : Membrane plate chamber, 19b ₁ , 19b ₂ , 19b ₃ : Membrane plate, 20 : Torque detector, 24 : Piston rod, 2
6: Monitor, 27: Switch contact. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A dual relay valve that is operated by compressed air supplied via a solenoid valve and sends compressed air controlled to a pressure corresponding to the commanded brake force as the first fluid pressure, and an electric brake force that corresponds to this. an electric-fluid pressure conversion valve that converts the fluid pressure into fluid pressure and sends it out as a second fluid pressure; and an auxiliary device that supplies fluid pressure obtained by subtracting the second fluid pressure from the first fluid pressure to the fluid brake as an output pressure. a relay valve; and a pressure switch that detects whether the total pressure of the output pressure and the second fluid pressure is greater than or equal to the first fluid pressure, and the pressure switch is configured to control the output pressure and the second fluid pressure. A membrane plate chamber into which the second fluid pressure is introduced, a membrane plate chamber arranged opposite to this membrane plate chamber and into which the first fluid pressure is introduced, and a membrane plate chamber connected to and connected to the movable part of the membrane plate forming these membrane plate chambers. 1. A brake monitoring device for an electric vehicle, comprising: a piston rod having a switch contact at an end thereof.