JPH0322056Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a brake fluid pressure control device equipped with a proportioning valve that reduces the brake fluid pressure from a master cylinder at a predetermined rate and supplies it to the wheel cylinder. More specifically, the present invention relates to a load-responsive braking hydraulic pressure control device that adjusts the activation start hydraulic pressure of the proportioning valve in accordance with changes in the load of a vehicle.

``Conventional technology'' Conventionally, the hydraulic pressure at which the proportioning valve starts operating is adjusted according to fluctuations in the vehicle's payload, so that a small braking force is obtained when the vehicle is empty and a large braking force is obtained when the vehicle is loaded. Load-responsive brake hydraulic control devices are known.

The conventional load-responsive brake fluid pressure control device includes a check valve that is installed in a passage that communicates the master cylinder and the wheel cylinder and allows the flow of brake fluid from the wheel cylinder to the master cylinder, and a housing that can be slid freely on the housing. and a plunger that is engaged with the check valve and is normally held in a non-operating position to open the check valve, so that the brake fluid pressure generated in the master cylinder is transferred from the check valve The check valve also acts on the plunger with a small pressure-receiving area on the upstream side, and acts on the plunger with a large pressure-receiving area on the downstream side of the check valve, reducing the braking fluid pressure according to the ratio of both pressure-receiving areas and supplying it to the wheel cylinder. a proportioning valve disposed between a vehicle body side member and a wheel side member of the vehicle, which applies an urging force to the plunger according to a change in a gap between the vehicle body side member and the wheel side member to adjust the proportioning. a link mechanism that adjusts the hydraulic pressure at which the proportioning valve starts operating;
A piston that displaces the plunger in the axial direction to adjust the urging force of the plunger by the link mechanism, and a vehicle height adjustment that selectively adjusts the height of the vehicle to a plurality of height positions by controlling fluid pressure. and a link mechanism that causes fluid pressure from the vehicle height adjustment device to act on the piston, and when the vehicle height is changed by varying the fluid pressure, the fluid pressure from the link mechanism changes as the vehicle height changes. It is known that the biasing force is compensated by the biasing force of the piston so that the biasing force acting on the plunger is maintained substantially constant before and after the vehicle height is changed by the vehicle height adjustment device. (Utility Model Application No. 59-39257).

According to the load-responsive braking hydraulic pressure control device having the above configuration, for example, when the height of the vehicle is increased by increasing the fluid pressure of the vehicle height adjustment device, the gap between the vehicle body side member and the wheel side member increases. The biasing force on the plunger from the link mechanism decreases, but at this time, fluid pressure from the vehicle height adjustment device is applied to the piston, causing the piston to bias the plunger by an amount corresponding to the decrease in the biasing force due to the link mechanism. Since the biasing force acting on the plunger is increased, the biasing force acting on the plunger is maintained substantially constant before and after the vehicle height is changed by the vehicle height adjusting device.

``Problem to be solved by the invention'' However, in conventional load-responsive braking hydraulic pressure control devices of this type, the piston was opposed to the plunger with a link mechanism in between, so the housing of the proportioning valve and the As a result, a link mechanism is interposed between the housing and the cylinder provided integrally with the housing, resulting in a complicated connection structure between the housing and the cylinder.

``Means for Solving the Problems'' In view of such circumstances, the present invention is based on the conventional load-responsive braking hydraulic pressure control device described above, in which the link mechanism and the piston are arranged on both sides of the plunger, and A positioning member is slidably fitted into the housing, and the check valve is movable in conjunction with the positioning member, and normally the plunger is brought into contact with the positioning member by a biasing force from the link mechanism. The piston is brought into contact with the piston and held in a non-operating position, and the piston is interlocked with the positioning member, so that when the fluid pressure increases, the positioning member is displaced toward the plunger to compensate for a decrease in the biasing force of the plunger due to the link mechanism. This is what I did.

"Function" According to the above configuration, for example, when the height of the vehicle is increased by increasing the fluid pressure of the vehicle height adjustment device,
The gap between the vehicle body side member and the wheel side member increases, and the biasing force of the plunger from the link mechanism decreases. On the other hand, the fluid pressure from the vehicle height adjustment device is applied to the piston, and the piston displaces the positioning member and the plunger in contact with it toward the link mechanism, so that the urging force of the plunger by the link mechanism is reduced. will be compensated.

Therefore, even if the gap between the vehicle body side member and the wheel side member changes, the biasing force acting on the plunger does not substantially change, so the biasing force acting on the plunger does not change when the vehicle height is changed by the vehicle height adjustment device. It becomes substantially constant between front and back.

Since the link mechanism and the piston are placed on both sides of the plunger, the link mechanism is not interposed between the proportioning valve housing and the cylinder integrally provided therein, as in the past. Therefore, the connection structure between the housing and the cylinder can be simplified.

"Example" The present invention will be explained below with reference to the illustrated example.
In FIG. 1, a housing 1 of the load-responsive braking hydraulic pressure control device is attached to a vehicle body side member (not shown). It communicates with a master cylinder (not shown).

The input port 3 communicates with an output port 5 formed on the left side of the center of the hole 2 via a proportioning valve 4 provided in the housing 1, and this output port 5 communicates with a rear wheel cylinder (not shown). ing. A front wheel cylinder (not shown) is communicated directly with the master cylinder without going through the proportioning valve 4.

A plunger 6 constituting a proportioning valve 4 is slidably fitted into the hole 2 formed in the housing 1, and the right side of the plunger 6 is kept liquid-tight by a sealing member 7. It is slidably penetrated into the plug 8 to be held, and its tip protrudes to the outside of the plug 8. In addition, the left end portion of the plunger 6 is as described in detail later.
It is held in that position by abutting against a tip-shaped positioning member 9 that is slidably fitted into the hole 2 and fixed at a predetermined position.

A large-diameter portion 6a is formed on the left side of the plunger 6, and the large-diameter portion 6a is slidably fitted into the hole 2, and a linear notch is provided on the outer circumferential surface of the large-diameter portion 6a. It is used as a fluid passage. Further, a valve body 10 having an L-shaped cross section is disposed on the right end surface of the positioning member 9, and the left end portion of the plunger 6 is passed through the shaft portion of the valve body 10, and the valve body 10 is positioned at the left side of the valve body 10. A valve seat portion 6b for seating is formed. The valve seat portion 6b and the valve body 10 constitute a check valve 11 that allows the braking fluid to flow from the wheel cylinder to the master cylinder. The plunger 6 is connected to the check valve 11.
It has a small pressure receiving area on the upstream side and a large pressure receiving area on the downstream side.

Further, when the valve seat portion 6b is in the non-operating position where its left end surface is in contact with the positioning member 9, it is separated from the valve body 10, and in this state, the large diameter portion A notch formed in the outer circumferential surface of 6a, a gap between the inner circumferential surface of the valve body 10 and the outer circumferential surface of the plunger 6, a gap between the valve body 10 and the valve seat part 6b, and a gap formed in the positioning member 9. Passage 1
The input port 3 and the output port 5 are communicated with each other via the port 2.

However, the housing 1 includes a link mechanism 15.
One end of a lever 16 constituting the lever 16 is swingably engaged, and a spring 19 is loaded between an adjustment bolt 17 screwed onto the lever 16 so that its position can be adjusted and a retainer 18 attached to the plunger 6. are doing. A spring 20 is attached to the other end of the lever 16.
One end of the spring 20 is connected to the other end of the spring 20, and the other end of the spring 20 is connected to one end of an L-shaped link 21 pivotally supported on the housing 1, and the other end of the L-shaped link 21 is connected to this and the wheel side member 22. It is connected to the wheel side member 22 via an adjustment rod 23 which is pivotally connected to the wheel side member 22.

Next, a cylinder 26 is integrally connected to the left side of the housing 1 in alignment with the axis of the hole 2, and a piston 27 is slidably fitted into the cylinder 26. A piston rod 28 provided at the right end of the piston 27 passes through a plug 29 and a sealing member 30 and is brought into contact with the positioning member 9.
1, it is held at the left sliding end position.

Fluid pressure from a vehicle height adjustment device 33 is constantly introduced into a pressure chamber 32 formed on the left side of the piston 27. This vehicle height adjustment device 33 selectively adjusts the height of the vehicle to a plurality of height positions by controlling fluid pressure.
3 is already known in the art, so a detailed explanation of its configuration will be omitted.

In the load-responsive braking hydraulic pressure control device having the above configuration, the vehicle height is set to “low” by the vehicle height adjustment device 33.
In this state, the fluid pressure introduced into the pressure chamber 32 from the vehicle height adjustment device 33 is small, so the piston 27 is biased by the spring 31 and located at the non-operating position shown on the left. . The plunger 6 is biased to the left by the biasing force from the spring 20, and is held at the non-operating position shown in the figure, where its left end abuts against the positioning member 9.

In this state, when brake fluid pressure is generated in the master cylinder (not shown), that brake fluid pressure is directly supplied to the front wheel cylinder (not shown), and at the same time is supplied to the input port 3 of the proportioning valve 4, and the input The brake fluid pressure supplied to port 3 is supplied to a rear wheel cylinder (not shown) via check valve 11 and output port 5.

When the brake fluid pressure increases, the check valve 11
Due to the difference in pressure receiving area between the front and rear plungers 6, a biasing force to the right is applied to the plunger 6.
When the biasing force becomes larger than the elastic force of the spring 20, the plunger 6 moves to the right, and the valve seat portion 6b provided thereon seats on the valve body 10, closing the fluid passage and supplying the fluid to the rear wheel cylinder. Stop the increase in brake fluid pressure.

After this, when the brake fluid pressure on the input port 3 side further increases, the plunger 6 moves to the left again to separate the valve seat portion 6b and the valve body 10. Accordingly, the plunger 6 moves forward and backward, and the brake fluid pressure to the rear wheel cylinders is increased at a lower rate of increase compared to the increase rate of the brake fluid pressure to the front wheel cylinders according to the ratio of the pressure receiving area before and after the check valve 11. raise.

In this state where the vehicle height is low, if the loading state changes, for example, if the vehicle changes from an empty state to a loaded state, the vehicle height will be lower accordingly, that is, the gap between the vehicle body side member and the wheel side member 22 will be reduced. becomes smaller. When the gap between the vehicle body side member and the wheel side member 22 becomes smaller, the L
Since the glyph link 21 is rotated clockwise in FIG. 1 and the spring 20 is stretched, the lever 16 is swung clockwise, and the plunger 6 is biased to the left via the adjustment bolt 17 more strongly than in the empty state. do.

As a result, the point at which the urging force due to the braking fluid pressure that urges the plunger 6 to the right becomes greater than the elastic force of the spring 20 is higher than when the vehicle is empty, and therefore the braking force supplied to the rear wheel cylinder is It is possible to increase the hydraulic pressure more than when the vehicle is empty and perform powerful braking.

Next, when the vehicle height is changed to "high" by the vehicle height adjustment device 33, the fluid pressure introduced into the pressure chamber 32 increases, so the piston 27 is moved by the spring 3.
1, the right step portion is displaced to the rightward end position where it abuts the plug 29. Then, the rod 28 of the piston 27 causes the positioning member 9, the plunger 6 and the valve body 10 that are in contact with the positioning member 9 to move to the right against the spring 20, thereby releasing the spring 20 applied to the plunger 6 relatively. Strengthens the repellency of.

However, when the vehicle height is changed to "high", the gap between the vehicle body side member and the wheel side member 22 increases, and the L-shaped link 21 is rotated counterclockwise in FIG. 1, causing the spring 20 to contract. Therefore, the biasing force applied from the spring 20 to the plunger 6 becomes smaller. In this embodiment, the amount of reinforcement of the biasing force of the plunger 6 due to the rightward movement of the piston 27, that is, the rightward movement amount S of the piston 27 and the plunger 6 is determined by the link mechanism when the vehicle height is changed to "high". The amount of reduction in the biasing force of the plunger 6 due to

Therefore, the biasing force acting on the plunger 6 can be maintained substantially constant before and after the vehicle height is changed by the vehicle height adjustment device 33.
Even if the vehicle height is changed by the vehicle height adjustment device 33, the link-type load-responsive braking hydraulic pressure control device is not adversely affected thereby.

Figure 2 shows another embodiment of the present invention.
This embodiment uses a proportioning valve 104 having a configuration different from that of the above embodiment. The proportioning valve 104 in this embodiment includes a plunger 106 that has a passage 135 that communicates between the input port 103 and the output port 105. A check valve 111 is provided.

The right end portions of the plunger 106 and the valve body 110 are brought into contact with a positioning member 109 so that the valve body 110 is normally separated from the valve seat 136, and the positioning member 109 is interlocked with the piston 127 for a predetermined distance S. This allows it to be displaced.

The rest of the configuration is the same as that in Figure 1, so the same parts as in Figure 1 are denoted by the same reference numerals.
00 is added, and it is clear that the same effect as the above-mentioned embodiment can be obtained in this embodiment as well.

``Effects of the invention'' As described above, according to the invention, even if the vehicle height is changed using the vehicle height adjustment device, accurate adjustments can be made in response to changes in the live load without any negative effects. In addition, since no link mechanism is interposed between the housing of the proportioning valve and the cylinder provided integrally therewith, the connection structure between the housing and the cylinder is simplified. This has the effect of being able to.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a sectional view showing another embodiment. 1,101...Housing, 6,106...Plunger, 4,104...Proportioning valve, 6b...Valve seat portion, 9,109...Positioning member, 11,111...Check valve, 15, 115...
...Link mechanism, 16,116...Lever, 20,
120... Spring, 21, 121... L-shaped link, 22, 122... Wheel side member, 27, 127
... Piston, 32,132 ... Pressure chamber, 33,
133...Vehicle height adjustment device, 136...Valve seat.

Claims (1)

[Scope of Claim for Utility Model Registration] A check valve that is provided in a passage communicating between the master cylinder and the wheel cylinder and allows the flow of brake fluid from the wheel cylinder to the master cylinder, and a check valve that is slidably fitted into the housing. and a plunger which is linked to the check valve and is normally held in a non-operating position to open the check valve. A small pressure-receiving area acts on the plunger, and a large pressure-receiving area downstream of the check valve acts on the plunger.
A proportioning valve is arranged between a vehicle body side member and a wheel side member of a vehicle, and is arranged between a vehicle body side member and a wheel side member, and a proportioning valve that reduces braking fluid pressure according to the ratio of both pressure receiving areas and supplies it to the wheel cylinder. A link mechanism that adjusts the hydraulic pressure at which the proportioning valve starts operating by applying a biasing force to the plunger according to the variation in the gap between the members; freely set up,
A piston that displaces the plunger in the axial direction to adjust the urging force of the plunger by the link mechanism, and a vehicle height adjustment that selectively adjusts the height of the vehicle to a plurality of height positions by controlling fluid pressure. and a link mechanism that causes fluid pressure from the vehicle height adjustment device to act on the piston, and when the vehicle height is changed by varying the fluid pressure, the fluid pressure from the link mechanism changes as the vehicle height changes. A load-responsive braking hydraulic pressure control device that compensates the biasing force by the displacement of the piston and maintains the biasing force acting on the plunger substantially constant before and after the vehicle height is changed by the vehicle height adjustment device. The link mechanism and the piston are arranged on both sides of the plunger, and a positioning member is slidably fitted into the housing, and the check valve is movable in conjunction with the positioning member. Usually, the plunger is brought into contact with the positioning member by the urging force from the link mechanism and held in the non-operating position, and the piston is interlocked with the positioning member so that the positioning member is activated when the fluid pressure increases. A load-responsive braking hydraulic pressure control device that compensates for a decrease in the biasing force of the plunger due to the link mechanism by displacing it toward the plunger.