JPH0211469B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake hydraulic pressure control device, and more particularly to a brake hydraulic pressure control device that allows braking characteristics when the vehicle is empty to be different from braking characteristics when the vehicle is loaded.

This type of brake fluid pressure control device is normally biased in one direction by a spring and held in a non-operating position, and is activated when the brake fluid pressure exceeds a predetermined value to increase the brake fluid pressure on the input side. A known model is equipped with a proportion valve that increases the output brake fluid pressure at a low pressure increase rate compared to the vehicle pressure, and a deceleration sensing valve that senses the deceleration of the vehicle and opens and closes a passage depending on the magnitude of the deceleration. It is being In a brake fluid pressure control device having such a configuration, when a predetermined deceleration is obtained with a low brake fluid pressure, such as when the vehicle is empty, the deceleration detects the valve and closes the deceleration sensing valve to reduce the fluid pressure. On the other hand, when the specified deceleration cannot be obtained even when the brake fluid pressure is relatively high, such as when loading a vehicle, the deceleration sensing valve is kept open to obtain high fluid pressure. Utilizing the large and small hydraulic pressures obtained in this way, when the vehicle is empty, the length of the spring that biases the proportion valve is kept long and the proportion valve is operated with low brake fluid pressure, and when the vehicle is loaded, the spring that biases the proportion valve is activated. The set length of the brake is shortened so that the proportion valve operates with high brake fluid pressure, thereby providing braking characteristics suitable for both when the vehicle is empty and when the vehicle is loaded.

However, with the conventional brake fluid pressure control device that changes the timing of the proportion valve operation by changing the set length of the spring as described above, it is possible to adjust the proportion valve to suit when the vehicle is empty by simply changing the set length of the spring. There are certain restrictions on obtaining the application force of the proportion valve and the application force suitable for loading the vehicle, so the braking characteristics when the vehicle is empty and the braking characteristics when the vehicle is loaded must be set separately and freely. It was difficult.

In view of these points, the present invention provides the first and second
The above first and second The present invention provides a brake hydraulic pressure control device that allows the braking characteristics when the vehicle is empty and when the vehicle is loaded to be freely set by individually setting the biasing force of the springs.

The present invention will be described below with reference to the illustrated embodiments.
In FIG. 1, 1 is a proportion valve provided in the casing 2, 3 is a deceleration sensing valve provided in the casing 2, and the proportion valve 1 is configured so that liquid is supplied to the hole 4 of the casing 2 by a sealing member 5. Plunger 6 fitted tightly and slidably
It is equipped with The plunger 6 is urged leftward by a first spring 8 elastically mounted between the casing 2 and the right end surface of a large diameter portion 6a formed at its left end. At the left end of the plunger 6 is a rod 9.
is provided, and when the plunger 6 is biased leftward by the spring 8 and positioned in the non-operating position shown in FIG. and protrudes into the chamber 11. A valve body 12 pushed up by the rod 9 is housed in this chamber 11, and the valve body 12 is urged by a spring 13 so as to be seated on a valve seat 14 formed around the through hole 10. However, since the elastic force of the first spring 8 is set to be larger than that of the spring 13, the plunger 6 is held in the non-operating position shown in the figure under normal conditions, and the valve body 12 is
The valve seat 14 is held away from the valve seat 14 by the valve seat 14.

Reference numeral 15 denotes an input hole formed in the casing 2, which is connected to a master cylinder (not shown) and communicates with a chamber 16 in which the first spring 8 is housed. This chamber 16 communicates with the chamber 11 housing the valve body 12 through a passage 17 formed in the casing 2, and further through a chamber 18 formed around the through hole 10 and the stepped portion of the plunger 6 and rod 9. It communicates with the output hole 19. This output hole 19
is connected to a rear wheel cylinder (not shown).

The deceleration sensing valve 3 includes a chamber 20 and a ball-shaped valve body 21 rotatably housed within the chamber 20. It is usually located at the lower part of the vehicle body in the direction of inclination. The upper part of the chamber 20 in the direction of inclination that accommodates the valve body 21 communicates with the chamber 11 that accommodates the valve body 12 of the proportion valve 1 via the valve mechanism 22 and the passages 23 and 17. The lower part is connected to the plunger 6 via the valve seat 24 and the passage 25 on which the valve body 21 is seated due to its own weight.
It communicates with a chamber 26 formed at the distal end side of the tube.

As shown in an enlarged view in FIG. 2, the valve mechanism 22 includes a disk-shaped plate body 28 having a through hole 27 formed approximately in the central axis thereof, and a passageway surrounding the plate body 28. The above-mentioned through hole 27 is closed on the 23 side by its own elasticity.
The valve body 30 includes an elastic body 29 made of rubber or the like having a flexible portion 29a that closes the passage 23, and a spring 31 that biases the valve body 30 in one direction to normally close the passage 23. Therefore, this valve mechanism 22
is opened when the brake fluid pressure in the chamber 11 exceeds a predetermined value and introduces the brake fluid pressure into the chamber 20, and when the brake fluid pressure in the chamber 11 decreases thereafter, the brake fluid pressure in the chamber 20 is opened. The pressure fluid introduced into the through hole 2
7 and the flexible portion 29 curved by the pressure thereof.
It is discharged to the chamber 11 side through the gap between a and the plate 28. Note that a valve mechanism having the same function can be constructed by providing two parallel branch passages in the middle of the passage 23 and providing each branch passage with a check valve that allows flow in opposite directions. .
Further, in FIG. 2, 32 is a retainer that receives the spring 31, 33 is a hole drilled in the shaft of this retainer, 34 is a stop ring that supports the retainer, and in FIG. 1, 35 is an air vent valve. It is.

Furthermore, at the right end of the plunger 6,
A piston 36 whose left end face faces the chamber 26 is slidably fitted therein, and the right end portion of the plunger 6 is slidably fitted into the shaft portion of the piston 36. A plate 37 for closing the hole in the shaft of the piston is attached to the right end surface of the piston 36, and a second spring 39 is elastically loaded between the plate 37 and the retainer 38 attached to the casing 2. Usually, the plates 37 and 36 are
It is held in the illustrated inoperative position shown in the figure. When both the plate 37 and the plunger 6 are in the non-operating position shown in the figure, the gap between the plate 37 and the right end surface of the plunger 6 is very small, and the plunger 6 moves to the right and the valve body 12 touches the valve seat 14. Before seating, the right end surface of the plunger 6 abuts the plate 37.

In the above configuration, when the brake pedal (not shown) is depressed to generate brake fluid pressure in the master cylinder, the brake fluid pressure is transmitted from the input hole 15 to the chamber 16, the passage 17, the chamber 11, the through hole 10, and the chamber 1.
8 to the output hole 19, and further to the rear wheel cylinder. At the beginning of braking when the brake fluid pressure is low, the plunger 6 of the proportion valve 1 does not operate, and as shown by the straight line A in Fig. 3, the input brake fluid pressure P _IN to the rear wheel cylinder, that is, the straight line above the master cylinder. Brake fluid pressure that is substantially the same as the brake fluid pressure that is introduced into the front wheel cylinder connected to the front wheel is introduced.

When the vehicle is empty, the relatively low brake fluid pressure causes the deceleration of the vehicle to exceed a predetermined value, as shown at point a in FIG.
due to inertia, it rolls to the left in FIG. 1 and leaves the valve seat 24. When the brake fluid pressure increases in this state and reaches the fluid pressure shown at point b in FIG. 3, the pressure fluid pushes open the valve body 30 of the valve mechanism 22 and flows into the chamber 20 from the passages 17 and 23. , further flows into the chamber 26 through the gap between the valve body 21 and the valve seat 24 and the passage 25. Then, the pressure fluid flowing into the chamber 26 moves the piston 36 to the right against the elastic force of the second spring 39, and the plunger 6 normally closes the gap between the right end surface of the plunger 6 and the plate 37. It is expanded to such a size that the plunger 6 does not come into contact with it when activated.

Then, when the brake fluid pressure increases further and becomes the fluid pressure shown in FIG. 8, the plunger 6 is moved to the right, and the valve body 12 is seated on the valve seat 14. As a result, the increase in the brake fluid pressure introduced into the rear wheel cylinder through the through hole 10 is stopped.

After this, when the brake fluid pressure further increases, the rightward biasing force acting on the left end surface of the plunger 6 does not increase due to the seating of the valve body 12, but the plunger pressure due to the brake fluid pressure introduced into the chamber 16 does not increase. 6's attached power to the left will be increased, so
The plunger 6 moves to the left to displace the valve body 12 from the valve seat 14. When the valve body 12 is separated from the valve seat 14, the brake fluid pressure acting on the rear wheel cylinder, that is, the left end surface of the plunger 6 increases, and the plunger 6 is moved to the right and the valve body 12 is moved to the right.
2 is seated on the valve seat 14. In this way, the plunger 6 double-moves back and forth to the left and right as the brake fluid pressure increases, and changes the brake fluid pressure P _OUT introduced into the rear wheel cylinder according to the pressure receiving area difference from the brake fluid pressure P _IN on the input side. (line B in Figure 3).

In contrast to the above-mentioned braking characteristics when the vehicle is empty, when the vehicle is loaded, the deceleration of the vehicle is small even if the brake fluid pressure pushes open the valve body 30 of the valve mechanism 22 (point b in Fig. 3). However, the valve body 21 continues to be seated on the valve seat 24 due to its own weight. Then, in this state, the valve body 30 is pushed open, and the brake fluid pressure is applied to the chamber 2.
0, this pressure fluid presses and holds the valve body 21 against the valve seat 24 due to the pressure difference between the pressure in the chamber 20 and the pressure in the passage 25 and the chamber 26, so that the brake fluid pressure increases thereafter. Even if the deceleration of the vehicle exceeds a predetermined value, the valve body 21 will not separate from the valve seat 24. In this state, no brake fluid pressure is introduced into the above-mentioned chamber 26, so the piston 3
6 and plate 37 continue to be held in the inoperative position shown. Therefore, even if the brake fluid pressure rises to point c in FIG. 3 in this state and the plunger 6 moves to the right, the plunger 6 hits the plate 37 before the valve body 12 seats on the valve seat 14. Since the valve body 12 is prevented from moving to the right by contacting the valve body 12, the valve body 12 does not sit on the valve seat 14.

When the plunger 6 is in contact with the plate 37, the plunger 6 is in contact with the first spring 8.
In addition to the biasing force from the second spring 39, the proportion valve 1 will not operate until the brake fluid pressure reaches a pressure much higher than point c in Figure 3. (see point d and straight line C in Figure 3), or it cannot operate normally due to the elastic force of the second spring 39 (see straight line A' in Figure 3). Even in this case, braking characteristics suitable for loading the vehicle can be obtained.

FIG. 4 shows an embodiment using a hydraulic pressure sensing valve having another configuration. In this embodiment, the valve mechanism 22 is omitted, and instead, a piston 41 is inserted into a hole 40 communicating with the passage 25. A rod 42 is attached to the piston 41 to push up the valve body 21, and a spring 44 is loaded between the piston 41 and a plug 43 that closes the hole.
Normally, the valve body 21 is moved to the valve seat 24 by the rod 42.
This was to prevent the person from sitting on the seat. Note that the other configurations are the same as in FIG. 1.

In this embodiment, the brake fluid pressure is transferred to the chamber 20 and the passage 2 via the passage 23 as soon as this occurs.
5 and the aforementioned chamber 26, and the brake fluid pressure acts on the left end surfaces of the piston 41 and the piston 36 to try to move them rightward. Therefore, when the vehicle is empty, if the piston 41 moves to the right and a predetermined deceleration is obtained before the valve body 21 seats on the valve seat 24, the valve body 21 will be seated on the valve seat 24. Since the piston 41 has already rolled to the left due to inertia before it moves to the right, the valve body 21 will not be seated on the valve seat 24 even if the piston 41 then moves significantly to the right. It is possible to introduce brake fluid pressure sufficient to cause the vehicle to move to the right, and braking characteristics when the vehicle is empty can be obtained in the same manner as in the above embodiment.

On the other hand, when loading a vehicle, before the valve body 21 rolls to the left due to inertia, the piston 41 moves to the right due to brake fluid pressure, and the valve body 21 moves toward the valve seat 24.
Since the valve body 21 is pressed against the valve seat 24 due to the subsequent rise in brake fluid pressure, brake fluid pressure sufficient to move the piston 36 to the right cannot be introduced into the chamber 26. Again, the braking characteristics when the vehicle is loaded can be obtained in the same manner as in the above-described embodiment.

Next, FIG. 5 shows an embodiment in which the present invention is applied to a two-system brake hydraulic pressure control device. Fifth
The two proportion valves 1A and 1B shown in the drawing, arranged parallel to each other, have substantially the same construction as the proportion valve 1 shown in FIG. It uses a speed sensing valve. In this embodiment, the chamber 20 of the deceleration sensing valve 3A is used as the passage 17 that communicates between the chambers 16 and 11 in FIG. A passage 45 communicates between the chamber 20 and the chamber 11A through a passage 46. Therefore, the deceleration sensing valve 3A is one of the proportion valves 1.
It is connected to the A side through the passages 45 and 46, and is independent from the other proportion valve 1B. The input hole 15A on the proportion valve 1A side is connected to a first system of a tandem master cylinder (not shown), and the output hole 19A is connected to, for example, a right rear wheel cylinder. Input hole 1 on the other proportion valve 1B side
5B is connected to the second system of the tandem master cylinder, and the output hole 19B is connected to the left rear wheel cylinder. Note that the chambers 16B and 11B of this proportion valve 1B are communicated with each other by a passage 17B as in FIG.

Furthermore, in this embodiment, the right end of the piston 41A of the deceleration sensing valve 3A is made to protrude outward from the casing 2, and a plate-shaped equalizer 47 corresponding to the above-mentioned plate 37 is provided in a small diameter portion protruding from the right end.
is slidably fitted. This equalizer 47 and the cover 48 attached to the casing 2
A second spring 49 is resiliently mounted between the equalizer 47 and the piston 41A, and the resiliency of the spring 49 normally holds the equalizer 47 and the piston 41A in the non-operating position shown in FIG.

In this embodiment as well, the same effect as in the above-mentioned embodiment can be obtained. That is, when the vehicle is empty, the valve body 21 of the deceleration sensing valve 3A rolls to the left due to inertia before it is seated on the valve seat 24, so that the subsequent increased brake fluid pressure acts on the piston 41A. Therefore, before both proportion valves 1A and 1B operate, the piston 41A is moved to the right and the equalizer 47 is moved to the plunger 6A of both proportion valves 1A and 1B.
It can be located at a non-interfering position where it does not come into contact with 6B. Therefore, each plunger 6A,
Since only the biasing forces of the first springs 8A and 8B act on each of the springs 6B, braking characteristics when the vehicle is empty can be obtained in both systems.

On the other hand, when loading a vehicle, the valve body 21 does not roll to the left until the valve body 21 seats on the valve seat 24, so the brake fluid moves the piston 41A to the right when the valve body 21 seats. The increase in pressure is limited, and the equalizer 47 is connected to both plungers 6A and 6B.
It is held in an interference position where it can come into contact with. Therefore, as in the previous embodiment, the proportion valve 1
In order for A and 1B to function properly, they must obtain an acting force sufficient to overcome the combined force of the applied force by the first springs 8A and 8B and half of the applied force by the second spring 49, and as a result, , the braking characteristics when the vehicle is loaded can be obtained.

Next, a case will be described in which one system of the tandem master cylinder is damaged. For example, when the system on the proportion valve 1A side is damaged, the equalizer 47 continues to be held at the non-operating position shown in the figure, since the hydraulic pressure acting on the plunger 41A cannot be obtained. On the other hand, if the other system is damaged, braking fluid pressure will be introduced into the chamber 20, but if only one system is used, the valve body 21 will be in contact with the valve seat 24 even when the car is empty. Since the predetermined deceleration cannot be achieved before the vehicle is seated, the equalizer 47 continues to be held at the non-operating position shown in the figure, as in the case when the vehicle is loaded. In other words, even if either system is damaged, the equalizer 47
is located at a position that interferes with the plunger 6A or 6B. In this state, for example, if only the plunger 6A attempts to operate, it must resist the combined force of the biasing force of the first spring 8A and the total biasing force of the second spring in order for it to operate normally. , substantially proportion valve 1A
normal functioning is prevented. Therefore, brake fluid pressure that has not been reduced can be introduced into both the front wheel side and rear wheel side wheel cylinders of the normal system.

As described above, the present invention is normally biased in one direction by the first spring and held in the non-operating position, and is activated when the brake fluid pressure exceeds a predetermined value to respond to the input hydraulic pressure. a proportion valve that increases the output hydraulic pressure at a low rate of increase; a biasing force transmitting member that receives the biasing force of a second spring; and a biasing force transmitting member that can freely move forward and backward against the second spring. A valve mechanism is provided in a passage that introduces brake fluid pressure to the piston member attached to the piston member and the pressure receiving surface at the other end of the piston member, and controls the opening and closing of the passage depending on the loaded state of the vehicle, such that the passage is open when the vehicle is empty and closed when the vehicle is loaded. and when the urging force transmission member interferes with the proportion valve, the second
Since the biasing force of the second spring is applied, braking characteristics can be obtained when the vehicle is empty and when the vehicle is loaded depending on whether or not the second spring is biased. Since the biasing forces of the springs can be set freely, the braking characteristics can be set more freely when the vehicle is empty and when the vehicle is loaded than in the past.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, FIG. 2 is an enlarged view of the main part of FIG. 1, FIG. 3 is a characteristic curve diagram showing braking characteristics, and FIG. FIG. 5 is a longitudinal cross-sectional view of a main part showing an embodiment of the present invention, and FIG. 1, 1A, 1B: Proportion valve, 2:
Casing, 3, 3A: Deceleration sensing valve, 6, 6
A, 6B: plunger, 8, 8A, 8B: first spring, 12, 12A, 12B: valve body of proportion valve, 15, 15A, 15B: input port, 19, 19A, 19B: output port, 21:
Valve body, 36, 41A: Piston, 37: Plate, 39, 49: Second spring, 47: Equalizer.

Claims (1)

[Claims] 1. Normally, it is biased in one direction by a first spring and held in a non-operating position, and is activated when the brake fluid pressure exceeds a predetermined value to output an output relative to the input hydraulic pressure. a proportion valve that increases hydraulic pressure at a low rate of increase; a biasing force transmitting member that receives the biasing force of a second spring; a piston member provided at the other end of the piston member, and a valve mechanism provided in a passage for introducing brake fluid pressure into the pressure receiving surface of the other end of the piston member, and controlling the opening and closing of the passage to open when the vehicle is empty and close when the vehicle is loaded, depending on the loaded state of the vehicle. A braking hydraulic pressure control device, comprising: applying the biasing force of the second spring to the proportion valve when the biasing force transmitting member interferes with the proportion valve. 2. The brake hydraulic pressure control device according to claim 1, wherein a proportion valve is provided for each of the two systems, and the urging force transmission member can interfere with both proportion valves.