JPH0136681Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a brake control device for an unmanned vehicle that runs using a motor as a drive source while detecting a magnetic field generated from a guide track laid on a running road surface.

Generally, in the case of an unmanned vehicle, a motor is used as a traveling drive source, and an electromagnetic brake that controls the drive shaft of the motor is used as a brake device. However, when using electromagnetic brakes,
Since it is installed at the rear end of the motor, the size of the motor becomes large, resulting in a space disadvantage.Moreover, the braking torque rises rapidly, which can impact the gears of the reducer, propeller shaft, etc., and shorten their lifespan. It can also cause oxidation. Further, there are other problems such as destabilization of the stopping position due to backlash of gears in the power transmission path from the motor to the wheels, and furthermore, it is difficult to change the braking force.

In view of the above-mentioned conventional problems, the purpose of this invention is to improve the pressure discharged from the hydraulic pump for power steering in an unmanned vehicle equipped with power steering and foot-type hydraulic brakes in order to enable passenger operation. To provide a brake control device for an unmanned vehicle that can operate a hydraulic brake using a part of oil without adversely affecting the performance of the power steering, and can obtain stable braking force. be.

Embodiments of the present invention will be specifically described below with reference to the drawings. Figure 1 shows an unmanned vehicle that runs using a motor as a drive source. In this figure, 1 is a guide track line laid on the road surface to guide the unmanned vehicle, 2 is the vehicle body (loading platform), and 3 is a passenger seat. A steering wheel for driving, 4 is a bumper attached to the front end of the vehicle body via a spring or the like (in a forward-reverse type, it is also attached to the rear end of the vehicle body), and 5 is a bumper that is used when the bumper 4 collides with an obstacle. This is a limit switch that detects this and issues a stop command to the vehicle. In addition to the emergency stop command from the limit switch 5, the vehicle is given a steady stop command at a pre-specified position on the transport line.

FIG. 2 shows an embodiment of a brake control device for an unmanned vehicle. As shown in the figure, power steering (hereinafter sometimes abbreviated as PS) includes a hydraulic pump 7 driven by a motor 6 for the PS, and a flow path for pressure oil sent from the hydraulic pump 7 to a handlebar 3. Control valve 8 that switches in response to the operation of
and a power cylinder 9 that uses the hydraulic pressure generated in the control valve 8 to apply power in the steering direction of the handle 3. On the other hand, foot-type hydraulic brakes use brake pedal 1.
0, lever 1 is activated by this brake pedal 10.
a master cylinder 12 actuated via 1;
A braking unit 1 including a wheel cylinder and the like for applying braking force to a braking wheel on an axle shaft using hydraulic pressure generated by a master cylinder 12.
It consists of 3.

Therefore, the present brake control device is as described above.
This is implemented in an unmanned vehicle that is equipped with a PS and hydraulic brakes and can switch to passenger driving as needed, and the details will be explained below. As shown in the figure, a flow divider valve 15 is provided in the discharge line 14 of the PS hydraulic pump 7, and the flow divider valve 15 supplies hydraulic pressure to the PS system line 16 and the hydraulic brake. The water is then diverted to a conduit 17 for a brake cylinder 18 for use during unmanned operation. The brake system conduit 17 is provided with a directional control solenoid valve 19 that is switched to the oil supply position when the solenoid is not energized and to the oil drain position when it is energized, and the switching is based on a stop command from the limit switch 5 or the like mentioned above. It will be done. It is preferable that the electromagnetic valve 19 be of a type that allows its switching operation to be performed relatively slowly in order to prevent sudden braking. In addition, a relief valve 20 is provided in the brake system line 17 between the diversion valve 15 and the solenoid valve 19, and a return line 21 for the relief valve 20 carries the return oil from the brake cylinder 18 and the diversion valve 15. Return pipe 2 for returning the pressure oil sent from the
Connected to 2. Note that 23 is a check valve that prevents pressure oil from erroneously flowing toward the brake cylinder 18 at the oil drain position of the solenoid valve 19.

The brake cylinder 18 is assembled into the actuation system of the master cylinder 12 via a lever 24 whose piston rod 18a is rotated integrally with the lever 11 for the master cylinder 12, and is connected to the brake system pipe described above. Master cylinder 1 when acted upon by pressure oil through passage 17.
Activate 2. Although the return of the brake cylinder 18 is performed by the return spring 10a for the brake pedal 10, a dedicated spring may be provided.

This embodiment is configured as described above,
During normal driving as an unmanned vehicle, the solenoid of the solenoid valve 19 is energized and switched to the oil drain position, so that the pressure oil is diverted from the PS hydraulic pump 7 to the brake system pipe 17 via the diverter valve 15. is returned to the tank from the solenoid valve 19 through the return line, and therefore the hydraulic brake is held in the released state. In such a state, when a stop command is given to the vehicle, the solenoid of the solenoid valve 19 is de-energized and switched to the refueling position based on the command.
The pressure oil in the brake system pipe 17 is transferred to the brake cylinder 1.
8, and the master cylinder 12 is actuated via the brake cylinder 18 and levers 24, 11. As a result, the brake part 13 is affected by the brake oil discharged from the master cylinder 12.
is activated and the axle shaft is braked.
Therefore, the flow dividing valve 15 is to ensure a constant flow rate in the regulated flow circuit, and in this embodiment, as is clear from the illustration, the PS side is the regulated flow circuit.
There is surplus flow on the brake system pipe line 17 side, but generally
Since the PS motor 6 is driven at a constant rotation, the amount of discharge from the hydraulic pump 7 is constant, and therefore the amount of excess oil sent to the brake system pipe 7 side via the diversion valve 15 is also always constant. Retained. In other words, the amount of oil supplied to the brake cylinder 18 is kept constant for each braking regardless of whether the PS is used or not, resulting in stable braking with no variation in braking distance.

As detailed above, the present invention enables an unmanned vehicle equipped with power steering and foot-type hydraulic brakes that can be switched to passenger operation to operate the hydraulic brakes using the hydraulic pressure of the power steering. Therefore, since the braking force is added to the axle shaft, which is the final position of the travel drive system, the initial shock of braking is smaller and the final Specifically, a strong braking force can be obtained, there is no adverse effect on the gears of the reducer, the propeller shaft, etc., and the stopping position of the vehicle can be stabilized.

In addition, the device of the present invention is configured by a combination of hydraulic piping and valves, etc., so it can be easily applied to existing vehicles, and the oil discharged from the hydraulic pump can be used for power steering and brakes using a diversion valve. By dividing the flow into two parts, it does not adversely affect the performance of the power steering, and the amount of oil supplied to the brake cylinder side can be kept constant, regardless of whether the power steering is used or not. It is possible to maintain a stable braking distance without variation each time the brake is activated. In addition, the present invention uses a brake cylinder to operate the operating member of the foot-type hydraulic brake, and the brake oil and brake control oil are not shared, so the brake oil is used as the brake oil. Plant-based oils suitable for maintaining performance can be used, while mineral-based oils can be used for power steering. Furthermore, since the device of the present invention performs the braking operation when the electromagnetic valve is not energized, the vehicle will stop even in the event of a failure of the electric circuit, and the vehicle will be prevented from running out of control, which is an advantage that cannot be overlooked.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic plan view of an unmanned vehicle, and FIG. 2 is an explanatory diagram showing a brake control device. 1... Guidance track line, 2... Vehicle body, 5... Limit switch, 7... Hydraulic pump, 12... Master cylinder, 15... Diversion valve, 16... Power steering system pipe, 17... Brake system pipe Road, 1
8... Brake cylinder, 19... Solenoid valve.

Claims (1)

[Scope of utility model registration request] In an unmanned vehicle equipped with hydraulic power steering and a hydraulic brake for braking a brake wheel on an axle shaft, the brake pedal is mechanically coupled via a lever to a brake pedal that operates a master cylinder of the hydraulic brake. A brake cylinder, a diversion valve that divides oil discharged from the hydraulic pump into a power steering system conduit and a brake system conduit, and a brake system conduit that connects this diversion valve and the brake cylinder. A brake control device for an unmanned vehicle, comprising a solenoid valve that is held in a position that blocks a system pipe and is switched to a position that communicates a brake system pipe when a stop signal is given.