JPS599964Y2 - Braking hydraulic pressure control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a brake fluid pressure control device that can approximate the braking force distribution between the front and rear wheels to an ideal braking force distribution curve. This allows braking fluid pressure from the master cylinder to be directly introduced into the rear wheel cylinder without reducing the pressure.

As a conventional braking device, one side of the tandem master cylinder is connected directly to the front wheel cylinder, and the other side of the tandem master cylinder is connected to the rear wheel cylinder via a brake fluid pressure control device, so that the braking force of the front and rear wheels is controlled to a predetermined value. In the following cases, the brake fluid pressure is directly introduced into the front and rear wheel cylinders, and when the braking force exceeds a predetermined value, the brake fluid pressure control device is activated to reduce the brake fluid pressure into the rear wheel cylinders. It is known that the front and rear wheels are always locked at the same time.

Conventional brake fluid pressure control devices usually include a valve body that opens and closes a flow path that communicates one of the tandem master cylinders with the rear wheel cylinder, and a valve body that is energized in one direction to remove the valve body from the valve seat. Normally, one of the master cylinders communicates with the rear wheel cylinder, and when brake fluid pressure is supplied from the master cylinder, the brake fluid pressure is reduced at a predetermined rate and sent to the rear wheel cylinder. It is equipped with a proportion valve for supply.

However, such conventional brake fluid pressure control devices,
When the brake fluid pressure supplied from the master cylinder exceeds the set value, even if the front wheel brake system is damaged, the brake fluid pressure is always reduced at a predetermined rate and the rear wheel cylinder is Therefore, if the front wheel brake system were to be damaged, the braking force would drop significantly, potentially creating a dangerous situation.

For this reason, in recent years, brake fluid pressure control devices have been proposed that can supply higher brake fluid pressure than normal to the rear wheel cylinders when the front wheel brake system is damaged. Even in such a brake fluid pressure control device, there is a drawback that the brake fluid pressure supplied to the rear wheel cylinder cannot be made equal to the brake fluid pressure generated in the master cylinder, or the brake fluid pressure supplied to the rear wheel cylinder is not equal to the brake fluid pressure generated in the master cylinder. Even if it is possible to supply the same brake fluid pressure as the above brake fluid pressure, the mechanism for this purpose is complicated or difficult to process, resulting in a significant increase in manufacturing costs.

Therefore, the present invention provides a brake fluid pressure control device equipped with the proportion valve, in which a second valve body is slidably fitted into the control device main body facing the proportion valve, and a second valve body is slidably fitted into the control device main body, and The proportion valve is constructed by storing the first valve body and its valve seat, and the abutting portion between the moving second valve body and the bottom surface of the main body fitting hole into which it is fitted allows the proportion valve to be configured. A communication path is formed to connect and disconnect the flow path on the upstream side of the first valve body and the flow path on the downstream side, and on the back side of the second valve body, there is a supply line for the front system side of the tandem master cylinder. By introducing hydraulic pressure so that the communication passage is actually held at the cutoff position, when both brake systems are normal, the proportion valve supplies braking hydraulic pressure to the rear wheel cylinders at a predetermined rate. On the other hand, if the front brake system is damaged and only the rear brake fluid pressure acts on the second valve body, the second
This is a simple structure in which the valve body is opened to communicate the communication passage, thereby allowing the braking fluid pressure generated in the master cylinder to be directly supplied to the wheel cylinder regardless of the operation of the proportion valve. A brake hydraulic pressure control device is provided.

The present invention will be explained below based on the illustrated embodiment. In the figure, 1 is the main body of the brake fluid pressure control device, 2 and 3 are the manpower hole and the output hole respectively formed in this main body, and the input hole 2 is the conduit 4. The output hole 3 is connected to one system of the master cylinder 5 through a conduit 6, and the output hole 3 is connected to the rear wheel cylinder 7 through a conduit 6, and as will be described in detail later, the manual hole 2 and the output hole 3 are connected to each other. The brake fluid pressure generated in the master cylinder 5 can be supplied to the rear wheel cylinder 7 through communication.

Further, the other system of the master cylinder 5 includes a conduit 8, an input port 9 formed in the main body 1, a pair of output ports 10 which are continuously connected to the input port, and a conduit 11 connected to each output port. It communicates directly with the front wheel cylinder 12 via.

A plunger 15 provided with a sealing member 14 is slidably fitted into a hole 13 bored in the main body 1, and the end portion of a small diameter portion 15a formed in the plunger 15 is provided in the main body 1. The plunger 15 is fitted into a hole 19 of a plug 18 provided coaxially with the hole 13 through a seal member 16 and a support member 17, and a rod 1 is fitted at the tip of the plunger 15.
5 b has a prominent shape.

The hole 19 communicates with the atmosphere through a through hole 20 formed in the plug 18.

21 is a spring that urges the plunger 15 to the left in the figure, and 22 is housed in a second valve body 24 that is slidably fitted into a hole 23 coaxially connected to the hole 13. A ball-shaped valve body 25 is a spring that urges the valve body 22 to the right, and the plunger 15 is loosely fitted through through holes 26 and 27 formed in the main body 1 and the second valve body 24. The rod 15b and the valve body 22 are in contact with each other due to the elastic forces of the springs 21 and 25 in opposite directions.

At this time, since the elastic force of the spring 21 is set to be larger than the elastic force of the spring 25, the plunger 15 is normally held at the non-operating position shown in the figure, and the valve body 22 is held at the rod 1.
A valve seat 28 formed around the through hole 27 by 5b
It is held in a completely separated position.

The plunger 15, spring 21, etc. constitute a proportion valve that reduces the braking fluid pressure from the master cylinder 5 at a predetermined rate and supplies it to the rear wheel cylinder 7.

In this state, the input hole 2 and the output hole 3 are connected to a chamber 29 housing a spring 21 that biases the plunger 15 in one direction, a passage 30, and a radial direction formed in the second valve body 24. Passage 31. They communicate with each other through the chamber 32, the gap between the valve body 22 and the valve seat 28, and the through holes 27 and 26, so that the braking hydraulic pressure of the master cylinder 5 can be supplied to the rear wheel cylinder 7.

Further, the second valve body 24 includes a cylindrical main body slidably fitted into the hole 23, a retainer 33 fitted into the left end of the main body, and a shaft of the main body. The valve body 22, the spring 25, and the valve seat 28 are housed in the chamber 32.

The through hole 26 is provided on the right end surface of the second valve body 24.
, 27 is provided, and the second valve element 24 is biased to the right by a header 35 to close the seal member 3.
4 is brought into pressure contact with the right end wall surface of the hole 23.

At this time, the magnitude of the elastic force of the spring 35 is set to such a level that even if the valve body 22 is pushed up against the elastic force of the spring 25, it will not be affected by it.

Therefore, in the illustrated non-operating position of the second valve body 24, there is a gap between the right end wall surface of the hole 23 and the right end surface of the second valve body 24, that is, the gap between the upstream passage 30 and the downstream side of the proportion valve. A communication path 36 that communicates with the through hole 26 is closed by a sealing member 34 .

A hole 2 into which the second valve body 24 is slidably fitted is provided.
3, the above-mentioned front brake side manual power port 9 and output port 10
The second valve body 24 faces the flow path communicating with the second valve body 24, so that the braking fluid pressure on the Freon I/brake side can be applied to the left end surface of the second valve body 24.

On the other hand, as is clear from the above explanation, the brake fluid pressure from the rear brake side acts on the right end surface side of the second valve body 24. In order to cancel out the acting force on the second valve body 24 due to both brake fluid pressures, that is, when both systems are normal, the pressure-receiving area of both end faces of the valve body 24 is reduced. They are set the same.

With the above structure, the brake fluid pressure generated in the master cylinder 5 is directly introduced into the front wheel cylinder 12 via the conduit 8, the input port 9, the output port 10, and the conduit 11, and at the same time , the input tube 2, the chamber 29, the passages 30, 31, the chamber 32, the gap between the valve body 22 and the valve seat 28, the through holes 27, 26, the output port 3, and the conduit 6 into the rear wheel cylinder 7. .

At this time, front-side and rear-side braking fluid pressures act on both end surfaces of the second valve body 24, but these brake fluid pressures are substantially the same pressure, and the second valve body 24 Since both end faces have the same pressure-receiving area, the forces of both braking fluid pressures acting on the valve body 24 cancel each other out, and therefore the valve body 24 is urged to the right by the elastic force of the spring 35. The connection path 36 is closed.

On the other hand, on the plunger 15, the facial control liquid pressure flowing through the chamber 29 acts on the step between the container body of the plunger 15 and the small diameter portion 15a, and the same pressure flowing through the through holes 27 and 26 acts on the plunger 15. Since the brake fluid pressure acts on the left end of the plunger 15, the plunger 15 tends to be moved to the right due to the difference in the pressure receiving area of the brake fluid pressure, but when the brake fluid pressure is still low in the early stage of braking, b21 The repulsive force is greater, and the plunger 15 is held in the non-operating position shown.

Therefore, the same braking fluid pressure as that of the front wheel cylinder and the front wheel cylinder is introduced to the rear wheel cylinder.

When the brake fluid pressure further increases and exceeds the set value, the plunger 15 moves to the right against the elastic force of the flap 21 due to the difference in pressure receiving area, and the spring The valve body 22, which is biased to the right by the valve 25, is the valve seat 2.
8, and stops the increase in brake fluid pressure supplied to the rear brake cylinder 7.

If the brake fluid pressure further increases, the valve body 2
2 is seated, so the force acting on the left end face of the plunger 15 to move it to the right does not increase, whereas the force acting on the stepped portion of the plunger 15 to move it to the left does not increase. Since the force increases with increasing brake fluid pressure,
The plunger 15 moves to the left again to displace the valve body 22 and increase the braking fluid pressure in the rear wheel cylinder 7.

As a result, when the brake fluid pressure acting on the rear wheel cylinder 7, that is, the left end of the plunger 15 increases, the plunger 15 moves to the right again to seat the valve body 22, thereby setting the brake fluid pressure. After the brake fluid pressure increases, the plunger 15 moves left and right to lower the brake fluid pressure in the rear wheel cylinder 7 to a level lower than that of the master cylinder 5 side, that is, the front wheel cylinder 12 side. It will be increased at an increasing rate.

However, in the unlikely event that the front brake fluid pressure cannot be obtained due to damage to the front brake system, only the rear brake fluid pressure will act on the second valve body 24. , the second valve body 24 is generally moved to the left against the elastic force of the spring 35 by a brake fluid pressure lower than the brake fluid pressure required to move the plunger 15 to the right, and communicates with the communication passage 36. .

Then, the master cylinder 5 and the rear wheel cylinder 7 are communicated directly through the communication passage 36 without communicating through the gap between the valve body 22 and the valve seat 28. Regardless of the operation, the same brake fluid pressure as the brake fluid pressure generated in the master cylinder 5 is supplied to the rear wheel cylinder 7 to perform a strong braking action.

If a conventionally known vehicle weight detection mechanism is linked to the plunger 15, a good braking force distribution curve between the front and rear wheels can always be obtained regardless of the loading state.

As described above, the present invention includes a control device body provided with an inlet hole connected to the rear system side of the tandem master cylinder and an outlet hole connected to the rear wheel cylinder, and a control device body provided with an inlet hole connected to the rear system side of the tandem master cylinder and an outlet hole connected to the rear wheel cylinder, and a A flow path, and a first valve body provided in this flow path is normally biased in one direction to separate it from its valve seat, thereby communicating the flow path while preventing the flow of air from the tandem master cylinder. A braking hydraulic pressure control device comprising a proportion valve that opens and closes the first valve body when the supply fluid pressure increases to reduce the supply fluid pressure at a predetermined rate and guide it to the outlet hole, wherein the proportion valve is arranged in the main body. A second valve body is slidably fitted to face the valve, and the first valve body and its valve seat are housed in the second valve body, thereby arranging the proportion valve. A communication passage that connects and disconnects the flow path upstream and downstream of the first valve body by a contact portion between the second valve body that moves forward and backward and the bottom surface of the main body insertion hole into which it is fitted. , and the supply hydraulic pressure from the front system side of the tandem master cylinder is introduced into the rear side of the second valve body so that the communication passage is normally maintained at the cutoff position. If the system side is damaged, the same braking fluid pressure as the braking fluid pressure generated in the master cylinder can be supplied to the lifter wheel cylinder, thereby significantly increasing safety in the event of damage to the front system.

Moreover, in the present invention, as described above, the second valve body is incorporated as a part of the proportion valve, and the contact portion between the second valve body and the bottom surface of the insertion hole is used as a bypass passage. Because of this structure, the overall length of the device assembled as a single structure can be significantly reduced, and there is an effect of excellent operability without requiring extra piping.

[Brief explanation of drawings]

The figure is a piping diagram showing a cross section of the main part of an embodiment of the present invention. 5...Tandem master cylinder, 7...
... Rear wheel cylinder, 15 ... Plunger, 22 ... Valve body, 24 ... Second valve body, 28 ... Valve seat, 36 ... ...Communication path.

Claims (1)

[Scope of utility model registration request] A control device body having an inlet hole connected to the rear system side of the tandem master cylinder and an outlet hole connected to the rear wheel cylinder, a flow path in the main body that communicates the inlet hole and the outlet hole, and a flow path provided in the flow path. Normally, the first valve body is biased in one direction and removed from its valve seat, thereby communicating the flow path. On the other hand, when the supply fluid pressure from the tandem master cylinder increases, the first valve body In the braking hydraulic pressure control device, the braking hydraulic pressure control device includes a proportioning valve that opens and closes a valve body to reduce the supplied hydraulic pressure at a predetermined rate and guide it to the outlet hole, wherein a second valve is disposed in the main body and faces the proportioning valve. The body is slidably inserted into the body, and the first valve body and its valve seat are housed in the second valve body to constitute the proportion valve, and the second valve body that moves back and forth and the second valve body move back and forth. The contact portion with the bottom surface of the main body insertion hole into which the valve body is inserted forms a communication path that connects and disconnects the flow path on the upstream side of the first valve body and the flow path on the downstream side. A brake hydraulic pressure control device characterized in that the supply hydraulic pressure from the front system side of the tandem master cylinder is introduced to the back side of the valve body so that the communication passage is normally maintained at a closed position.