JPS6335887Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pedal operation mechanism for a new brake oil exchange device used when extracting obsolete brake oil from the hydraulic brake circuit of automobiles, railway vehicles, etc. and replacing it with new brake oil. It is something.

The brake oil is replaced by draining the old brake oil from the discharge valve of the hydraulic brake circuit and then supplying new brake oil from the master cylinder section. However, since air bubbles are generated when new brake oil flows into the emptied hydraulic brake circuit, the first portion of the new brake oil containing air bubbles must be drained out of the hydraulic brake circuit. For this reason, in the past, the hydraulic brake circuit was designed so that the worker who repeatedly pressed the brake pedal would notify the worker visually checking the state of the brake oil when the brake pedal was pressed, and the discharge valve of the brake cylinder would open only when the brake pedal was pressed. It was necessary to prevent the discharged brake oil from flowing back into the system, which required manpower and effort, resulting in low work efficiency.

The present invention was completed with the aim of solving the above-mentioned drawbacks and providing a pedal operation mechanism for a brake oil exchange device that can efficiently exchange brake oil. Explain in detail.

As is well known, in a vehicle A, such as an automobile, in which oil is to be changed, a piston 2 of a master cylinder 1 is moved forward and backward by depressing a brake pedal 3, and pressure oil is sent to a brake cylinder 4 from an oil supply cup 18. . An oil discharge pipe 6 is connected to each brake cylinder 4 at one end so that it can be easily attached and detached, and an oil discharge pipe 6 is connected to the valve chamber 12 in the middle of the oil discharge pipe 6 from the brake cylinder 4 side. A control valve 5 is provided in which a spherical movable valve 13 that slides in accordance with the flow resistance of the oil being sent is urged by a spring 14. A main flow path 6a and a bypass flow path 6b are formed at the front end of this oil discharge pipe 6, and the main flow path 6a includes a pump 8 driven by a motor 7, a pressure switch 10, and a needle valve 9. A check valve 11 is provided in the bypass flow path 6b.
is provided. Further, in the control valve 5, the movable valve 13 is normally pressed against the seat portion 15 on the inlet side by the elasticity of the spring 14, thereby blocking communication between the brake cylinder 4 and the discharge end 16 of the oil discharge pipe 6. 22 is a brake pedal pressing piston 27 that presses the brake pedal 3 intermittently.
A pressurized fluid source is switchably connected to the supply/discharge port of the cylinder 22 via the cylinder switching valve 23, and the cylinder switching valve 23
Cylinder back pressure detection valves 24 and 25 connected to a pressurized fluid source are connected to each switching control section. The switching control parts of the cylinder back pressure detection valves 24 and 25 are connected to the supply and exhaust pipes of the cylinder 22, and when the back pressure of the cylinder 22 becomes close to atmospheric pressure, the switching control parts of the cylinder back pressure detection valves 24 and 25 are connected to the supply and discharge pipes of the cylinder 22. For this purpose, one switching control section of the cylinder switching valve 23 is depressurized, and the other switching control section, which is pressurized, switches the cylinder switching valve 23 to close communication with the pressurized fluid source. 23 is a switching valve, 26 is a switching valve that switches the pressurized fluid source to open and close;
0 is the stroke detector of the piston 27, 31,3
2 is a needle valve.

In a vehicle constructed in this way, when replacing the brake oil, it is first necessary to remove the old brake oil. For this purpose, the pump 8 is operated to suck the brake oil in the hydraulic brake circuit through the brake cylinder 4 and the oil discharge line 6 with the control valve 5, and discharge it through the discharge end 16 thereof. At this time, the pressure inside the valve chamber 12 of the control valve 5 is lower than that of the inlet hole connected to the hydraulic brake circuit, so this differential pressure causes the movable valve 13 to slide to the right and separate from the seat portion 15. , the oil discharge pipe 6 and the hydraulic brake circuit are communicated with each other. If the brake oil should flow backward during this suction operation, the movable valve 13 will come into contact with the seat on the inlet side and close the conduit. During the suction operation, this control valve 5 also functions as a fixed orifice circuit to maintain the suction pressure at a constant value. This function as a fixed orifice circuit is particularly effective when there are multiple brake cylinders 4 and brake oil is sucked from these brake cylinders 4 at the same time.
Even after the hydraulic brake cylinder 4 is emptied, suction from the other brake cylinder 4 continues, and the brake oil in the entire hydraulic brake circuit is completely drained. When the discharge of the old brake oil is completed in this way, the pressure in the main flow path 6a, which is the piping on the discharge side of the pump 8, which had been showing a high pressure due to the action of the needle valve 9, drops rapidly. This pressure change is detected by the pressure switch 10 and the pump 8
At the same time as stopping the extraction, a message indicating completion of extraction is displayed.
At the same time, a signal is issued instructing the start of filling new brake oil. Filling with new brake oil
Oil supply passage 19 to oil supply cup 18 of master cylinder 1
It is started by supplying new brake oil from. A switching valve 20 is provided in the oil supply path 19, and a liquid level gauge 2 attached to the oil supply cup 18 is provided.
1 to maintain a constant level of the liquid level in the refueling cup 18. After filling the oil supply cup 18 with a predetermined amount of new brake oil and switching the switching valve 26 to connect the pipe line with the pressurized fluid source, the cylinder 2
The cylinder switching valve 23 which connects the supply/discharge port 2 to the pressurized fluid source supplies pressurized fluid to the right side of the cylinder 22 where the pressing part of the piston 27 faces the brake pedal 3. Move to the left and press the brake pedal 3. When the brake pedal 3 is pressed to the limit, the piston 27 stops, but due to the piston stopping, the cylinder 22
Since the back pressure of the cylinder 22 decreases to near atmospheric pressure, the cylinder back pressure detection valve 2 connected to the supply/discharge pipe of the cylinder 22
The switching control section 4 is depressurized and switches the cylinder back pressure detection valve 24, and as a result of this switching, the cylinder back pressure detection valve 24, which is connected to the pressurized fluid source and connected to the switching control section of the cylinder switching valve 23, is pressurized. Since the communication with the pressure fluid source is closed and the pressurization of one switching control part of the cylinder switching valve 23 is released, the cylinder switching valve 23 is switched by the other switching control part in the pressurized state. As a result of this switching, the cylinder back pressure detection valve 24 is immediately switched to its original position and communicated with the pressurized fluid source, and one switching control section of the cylinder switching valve 23 is pressurized again, but the other switching control section is pressurized again. The cylinder switching valve 23 maintains the switching state because the pressure is balanced with the switching control section that has been switched. As a result, pressurized fluid is supplied to the left side of the cylinder 22 and the piston 2
7 returns to the right, but stops at the stroke end, so the back pressure drop due to this is reduced by reducing the pressure in the switching control section of the cylinder back pressure detection valve 25 connected to the supply/discharge pipe of the cylinder 22. In order to switch the cylinder switching valve 23, the cylinder back pressure detection valve 25, which is connected to the pressurized fluid source and to the switching control section of the cylinder switching valve 23, closes communication with the pressurized fluid source and switches the other cylinder switching valve 23. Since the pressure in the control section is released, the cylinder switching valve 23 is switched by the switching control section in the pressurized state. As a result of this switching, the cylinder back pressure detection valve 25 is immediately switched to the old position and communicated with the pressurized fluid source, and the other switching control section of the cylinder switching valve 23 is pressurized again, but one pressurized The cylinder switching valve 23 maintains the switching state because the pressure is balanced with the pressure in the switching control section. As a result, pressurized fluid is supplied to the right side of the cylinder 22, and the piston 27 returns to the left. In this way, the brake pedal 3 is automatically and repeatedly pressed. By repeatedly pressing the brake pedal 3 in this way, the piston 2 of the master cylinder 1 sequentially supplies new brake oil in the oil supply cup 18 into the hydraulic brake circuit, and the new brake oil is supplied in accordance with the amount of supply. Brake oil is in oil supply path 19
will be automatically replenished from In this way, the hydraulic brake circuit is filled with new brake oil, and as mentioned at the beginning, the brake oil containing air bubbles passes through the control valve 5 and the bypass flow path 6b to the oil discharge pipe 6.
to overflow. The action of the control valve 5 in this case is that the valve chamber 12 is located inside the cylindrical valve chamber 12.
A spherical movable valve 13 having a diameter smaller than the inner diameter of the valve is supported by a spring 14.
It is pushed to 5. However, when new brake oil fills the hydraulic brake circuit and the pressure applied by the piston 2 of the master cylinder 1 is transmitted to the brake oil in the inlet hole of the control valve 5, the pressure of the brake oil resists the force of the spring 14 and the movable valve 13 is moved to the right from the seat portion 15, and new brake oil containing air bubbles flows into the oil discharge pipe 6 through the control valve 5. At this time pump 8
Since the brake oil has stopped, the brake oil passes through the check valve 11 of the bypass passage 6b and is discharged to the discharge end 16.
It will flow to While the brake oil containing bubbles is flowing in this manner, the movable valve 13 is maintained at a position slightly apart from the seat portion 15 due to the flow resistance of the brake oil. Note that when the piston 2 of the master cylinder 1 returns, the pressure inside the hydraulic brake circuit is reduced, so the movable valve 13 returns to its old position by the force of the spring 14, preventing backflow and creating a negative pressure inside the hydraulic brake circuit. By keeping the brake fluid at a constant temperature, it helps reduce the formation of air bubbles and facilitates the filling of new brake fluid. When the brake oil containing air bubbles is discharged from the oil discharge pipe 6 in this manner, the hydraulic brake circuit is filled with brake oil that does not contain air bubbles, and the brake oil overflows through the control valve 5. . However, brake oil that does not contain air bubbles has a higher apparent density than brake oil that contains air bubbles, and the movable valve 13 receives a large flow resistance and is pressed against the seat portion 28 on the outlet side against the force of the spring 14. cut off the flow. Therefore, the control valve 5 has the function of allowing brake oil containing air bubbles to pass through, but automatically blocking brake oil that does not contain air bubbles, thereby preventing unnecessary outflow. As the air bubbles in the hydraulic brake circuit decrease, the stroke of the piston 2 of the master cylinder 1 gradually becomes smaller, and when the hydraulic brake circuit reaches a state filled with bubble-free brake oil, the stroke of the piston 2 decreases. is a constant stroke determined by the position of the communication hole 29 with the oil supply cup 18. The stroke of the piston 2 is detected by a stroke detector 30, and when the stroke reaches a constant value, the filling process with new brake oil is considered complete and the operation of the entire device is stopped. As mentioned above, when the piston 27 of the cylinder 22 stops, the change in back pressure is detected and the cylinder switching valve 23 is switched, so the stroke of the piston 2 gradually decreases, and as a result, the stroke of the brake pedal 3 gradually decreases. It is possible to repeat the reciprocating motion while following the change in the stroke of the brake pedal 3 even when the brake pedal 3 is moved. In the manner described above, the removal of old brake oil and the filling of new brake oil are performed fully automatically. In addition, although the above explanation describes how the brake oil is drained and filled in a fully automatic manner, it is not necessarily necessary to do so automatically, and the stroke detector 30 is used to detect the piston without using the oil discharge pipe 6. In addition, a buzzer, lamp, etc. are activated only when the brake pedal 27 is moving forward, and a vinyl hose is connected to the discharge valve of the brake cylinder 4 so that the worker can use the buzzer or lamp to confirm when the brake pedal 3 is pressed while braking. Of course, this may be done by opening the discharge valve of the cylinder 4 to prevent the discharged brake oil from flowing back into the hydraulic brake circuit, while visually checking for the presence of air bubbles in the brake oil.

As is clear from the above description, the present invention uses a cylinder back pressure detection valve that is switched when the cylinder back pressure approaches atmospheric pressure, and a cylinder switching valve that is switched by the cylinder back pressure detection valve to cause the piston of the cylinder to reciprocate. In addition, a stroke detector detects the stroke of the piston to determine whether brake oil has been filled, so that workers who repeatedly press the brake pedal are not required to press the brake pedal repeatedly. It also eliminates the need for workers to check the brake oil filling, significantly increasing work efficiency.
This pedal operating mechanism for a brake oil exchange device eliminates the inconveniences associated with conventional brake oil exchange, and is of great practical value.

[Brief explanation of drawings]

The drawing is a circuit diagram showing an embodiment of the present invention. 22...Cylinder, 23...Cylinder switching valve,
24... Cylinder back pressure detection valve, 25... Cylinder back pressure detection valve, 27... Piston, 30... Stroke detector.

Claims (1)

[Scope of utility model registration request] A supply/discharge port of a cylinder 22 provided with a piston 27 for pressing the brake pedal is connected to a pressurized fluid source via a cylinder switching valve 23 so as to be freely switchable, and a switching control section of the cylinder switching valve 23 is connected to the pressurized fluid source. The connected cylinder back pressure detection valves 24 and 25 are connected, and the switching control parts of the cylinder back pressure detection valves 24 and 25 are connected to the supply and discharge pipe of the cylinder 22, and
A pedal operation mechanism for a brake oil exchange device, characterized in that a stroke detector 30 for detecting the stroke of the piston 27 is provided.