JPS6015246A - Hydraulic controller of brake for vehicle - Google Patents

Abstract

PURPOSE:To prevent a locking phenomenon reliably, by a method wherein starting pressure for a pressure reducing action of a pressure reducing valve is controlled according to pressure of an air spring and when the air spring is out of order, the pressure of the air spring is enclosed, through the enclosed pressure of which the pressure reducing valve is controlled. CONSTITUTION:A balancing lever 18 is built between end parts of two valve levers 9a of each of pressure reducing valves 51, 52. A protrusion 19a of a piston 19 is abutted against the balancing lever 18 and a right end face of the piston is confronted with a pressure chamber 20. The pressure chamber 20 is connected with the air spring 22 through an enclosing valve mechanism 31. Starting pressure, therefore, for pressure reducing action of each of pressure reducing valves 51, 52 is controlled according to carrying capacity of a vehicle. When troubles occur on an air spring system 22, pressure to be decided by set load of a valve spring 38 of a second control valve 36, of the enclosing valve mechanism 31 is enclosed within the pressure chamber 20. Starting pressure, therefore, for pressure reducing action of each of the pressure reducing valves 51, 52 is controlled by the enclosed pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a brake hydraulic pressure control device in a vehicle, in particular, an oil passage connecting between an output port of a mask cylinder and a rear wheel brake, so that the output hydraulic pressure of the output port is proportional to the rear wheel brake. The present invention relates to a device that is equipped with a pressure reducing valve that can reduce and transmit a pressure, thereby preventing a rear wheel locking phenomenon caused by a reduction in rear wheel load associated with braking.

When braking a vehicle using this type of device, in order to make the braking approximate ideal braking, the pressure at which the pressure reducing valve starts its pressure reducing action must be changed according to the loaded weight of the vehicle. It is necessary to make the depressurization start pressure higher than that when the car is empty.

Conventionally, the pressure at which the pressure reducing valve starts reducing the pressure is determined by the set load of the spring, so the pressure is always constant and cannot be changed depending on the loaded weight.

In view of the above, the present invention utilizes an air spring used in a suspension system to change the pressure at which the pressure reducing valve starts reducing the pressure according to the loaded weight of the vehicle, and also allows the system to be used in the event of a failure in the air spring system. The object of the present invention is to provide a highly safe brake hydraulic control device that temporarily confines the pressure of the air spring to the pressure reducing valve side and determines the pressure at which the pressure reducing action of the pressure reducing valve starts. A pressure reducing valve is installed in the oil passage connecting the output boat and the rear wheel brake, and the pressure reducing valve can proportionally reduce the output hydraulic pressure of the output capo 1 and transmit it to the rear wheel brake. The air spring of the suspension system, which determines the starting pressure according to the loaded weight of the vehicle, is connected to the pressure reducing valve via a pressure path so that the pressure of the air spring urges the pressure reducing valve in the opening direction. Under normal conditions, the pressure is transmitted to the pressure reducing valve, but in the event of a failure of the air spring, a sealing valve mechanism is provided to temporarily confine the pressure to the pressure reducing valve so that the pressure at which the pressure reducing valve starts to work can be determined. It is installed in the pressure path.

Hereinafter, an embodiment in which the device of the present invention is configured in two systems will be described with reference to the drawings. In FIG. 1, AI is a known tandem type mask cylinder operated by a brake pedal 1, Br, and Br2 are on the left.

The right rear brake is shown. Reference numeral 2 denotes a valve face fixed to a proper position on the vehicle body (not shown), and an oil path . The first .
Second population 30, 32, oil route L, r, L 2 r
The first and second outlets 4. are connected to the left and right rear wheel brakes Br, , Br2, respectively, via 4. ．． 42 are open and control communication between the first port 31 and the first outlet 44 and the second port 32 and the second outlet 42, respectively. ．． 52 are provided in parallel within the valve copper 2. Left and right front wheel brakes Bf1. Bf2 is connected to oil passages L2, L, and oil passages L2f, L1f which are branched from the oil passages L2, L.

The first pressure reducing valve 51 includes an input hydraulic chamber 6 and an output hydraulic chamber 7 that communicate with the first population 31 and the first outlet 4I, respectively.
Consisting of an elastic valve seat 8 made of rubber or the like installed between the two hydraulic chambers 6 and 7, and a valve body 9 that cooperates with the valve seat 8 to communicate and cut off the two hydraulic chambers 6 and 7. be done. The valve body 9 is
A piston-shaped valve portion 9h that cooperates with the valve seat 8 and a guide shaft 9C that protrudes from its outer end surface are integrally formed at the tip of a valve rod 9a that passes through the valve hole of the valve seat 8 and the input hydraulic chamber 6. The base of the valve rod 9a is slidably supported by a bearing 10 forming the outer end wall of the input hydraulic chamber 6 via a seal member 11, and the valve portion 9h and the protruding shaft 9C are arranged in the output hydraulic chamber 7. Then, the protruding shaft 9c is loosely fitted into the small diameter hole 12 of the inner hydraulic chamber 7. A coil spring 13 that holds the valve seat 8 and the seal member 11 is compressed between the valve seat 8 and the seal member 11 .

The second pressure reducing valve 52 connects the output hydraulic chambers 6 and 7 to the second pressure reducing valve 52.
2. It has the same structure as the first pressure reducing valve 51 described above except that it communicates with the second outlet 4°, and parts corresponding to the first pressure reducing valve 51 are given the same reference numerals.

Further, the valve surface 2 includes first and second pressure reducing valves 5. .

A housing 14 is fixed with bolts 15, and includes a large-diameter lever accommodating portion 14a adjacent to the input hydraulic chambers 6, 52, and a small-diameter cylinder portion 14h communicating with the lever accommodating portion 14a. In the lever housing portion 144, a circular balance lever 18 is housed, which bridges between the ends of the valve rods 9α, 9α of the two pressure reducing valves 51, 5□0 that protrude into the lever housing portion 144. A piston 19 is slidably fitted within the cylinder portion 14h, and a pressure chamber 20 is defined between the outer end surface of the piston 19 and the inner wall surface of the cylinder portion 14h. The inner end surface of the piston 19 has a protrusion 19a having a hemispherical tip surface.
is provided protrudingly, and its tip face faces the hemispherical concave surface 1B+7 formed at the center of the balance lever 18.

In the pressure chamber 20, an air spring type vehicle height adjustment mechanism 21 of the suspension system includes an air compressor 24, a pressure accumulator tank 25 for storing compressed air, an air spring 22, and a compressed air from the pressure accumulator tank 25 to the air spring 22. It has a control valve 26 that can introduce air into the air chamber 23 and exhaust it therefrom, as well as a coil spring 27.

The coil spring 27 is designed to handle only the empty vehicle type, and the air spring 22 is responsible for the loaded type. That is, compressed air regulated by the control valve 26 according to the load weight is introduced into the air chamber 23 of the air spring 22, thereby keeping the vehicle height constant. If the air pressure is high and the loaded weight is light, the air pressure inside the air chamber 23 will be low.

The same air pressure as the air chamber 23 of the air spring 22, that is, the air pressure corresponding to the loaded weight, is introduced into the pressure chamber 20 of the cylinder part 11 except when the vehicle is empty, and this causes the piston 19 to move to the first position.
In the figure, it slides to the left, and the distal end surface of the protrusion 19a abuts the concave surface 18a of the balance lever 18, causing both the valve bodies 9, 9
Since the two valve bodies 9, 9 are slid in the same direction, the valve portions 9h of both the valve bodies 9, 9 are held at positions separated from the valve seat 8, respectively. 28 is an orifice formed in the outer end wall of the cylinder portion 14h;
When the air pressure on the air spring 22 side pulsates, this is attenuated to prevent sudden fluctuations in the air pressure within the pressure chamber 20 of the cylinder portion 14h.

Pneumatic path 16 between pressure chamber 20 and air chamber 23 of air spring 22
A sealing valve mechanism 31 is installed to temporarily seal air pressure within the pressure chamber 20 and prevent it from leaking into the air spring system 22 when the air spring system fails.

The valve copper 32 of the mechanism 31 has an inlet 33 on the air spring 22 side, an outlet 34 on the pressure chamber 20 side, and so on.

The first and second passages 350 and 352 are parallel to each other and communicate between the outlets 33 and 34. A one-way valve type control valve 36 that allows air pressure to be introduced only from the air spring 22 into the pressure chamber 20 is located in the first passage 35°. However, the second passage 352
A one-way valve type second control valve 36° that allows air pressure to be discharged only from the pressure chamber 20 to the air spring 22 is disposed at each of the two control valves. The first and second control valves 361-362 each include a valve body 37 made of steel balls, a valve spring 38, and a first and second control valve 361-362. Second passage 35
1.

9- There is.

The set load of the valve spring 38 of the first control valve 36 is such that when the air pressure in the air chamber 23 in the air spring 22 acts on the valve element 37, it immediately separates it from the valve seat 39, thereby separating the air chamber 23 and the pressure chamber 20. It is set low to allow communication.

The set load of the valve spring 38 of the second control valve 36□ is such that if the air pressure generated in the pressure chamber 20 acts on the valve body 37 at the start of the depressurization action when there is one occupant in the vehicle, it will be immediately released from the valve seat 39. the first control valve 36. valve spring 38
is set higher than .

In this way, the first. Second control valve 36. ．． If the air spring system is configured to open and close in opposite directions, the air pressure is temporarily contained within the pressure chamber 20 and both pressure reducing valves 5. ．． 5. The pressure at which the decompression action starts can be determined.

10- Next, the operation of this embodiment will be explained. While the vehicle is running, the brake pedal 1 is depressed to activate the mask cylinder AI,
If hydraulic pressure is output from the first and second output ports P1 and P2, the output hydraulic pressure of the first output port P1 will be output from the oil path L1.
, L, f to the right front wheel brake Bft, and the first reduction valve 5. The hydraulic pressure is transmitted from the human-powered oil well chamber 6 to the left rear wheel brake Br through the output hydraulic chamber 7 and the oil passage, which communicate with each other, to operate them. On the other hand, the output oil pressure of the second output port P2 is transmitted to the left front wheel brake Bf1 through oil passages L2 and L2f, and from the input oil pressure chamber 6 of the second pressure reducing valve 52 to the output oil pressure chamber 7 communicating therewith and through the oil passage L2r to the right side. The signals are transmitted to the rear wheel brakes Br2 to operate them.

Then, the first cylinder of mask cylinder A/. 2nd output capo-11
',, /), when the output oil pressure rises to the predetermined receipt '2,
1st. Second pressure reducing valve5. ．． 52 is the rear wheel brake Br,,B
This starts to control the hydraulic pressure of r2, and its operation will be explained in detail next.

First, due to the increase in the output oil pressure of the first output port P, the first
510 pressure reducing valves, output hydraulic chamber 6. When the hydraulic pressure reaches a predetermined value, the hydraulic pressure acting on the valve body 9 causes a pushing force in the right direction (corresponding to the cross-sectional area A of the base of the valve rod 9a multiplied by the hydraulic pressure in the output hydraulic chambers 6 and 7). ) overcomes the biasing force exerted on the valve body 9 of the pressure chamber 20 of the cylinder portion 14b, moves the valve body 9 to the right in the figure, and seats the valve portion 9h on the valve seat 8. Communication between chambers 6 and 7 is cut off. In this case, the pressure inside the pressure chamber 20 is increased by the rightward movement of the piston 19, but the increased pressure is released to the air spring 22 side by opening the second control valve 362, and then the first control valve 362 is opened. 361 opens, and the air pressures in the pressure chamber 20 and the air chamber 23 are balanced.

After that, if the output oil pressure of the first output port P1 further increases, the leftward pressing force of the valve body 9 due to the oil pressure of the input oil pressure chamber 6 (the difference between the cross-sectional area B of the valve part 9h and the cross-sectional area A) (approximately equivalent to the product of the oil pressure of the output oil pressure chamber 6) is the rightward pressing force of the valve body 9 due to the oil pressure of the output oil pressure chamber 7 (approximately equivalent to the product of the cross-sectional area B multiplied by the oil pressure of the output oil pressure chamber 7) do.

), the valve body 9 is pushed back to the left, the valve part 9h is separated from the valve seat 8, and the two hydraulic chambers 6 and 7 are communicated again, so the pressure in the output hydraulic chamber 7 is increased. The rightward pressing force of the valve body 9 due to the hydraulic pressure of the output hydraulic chamber 7 immediately increases, and the valve body 9 is moved to the right again to cut off the communication between the two hydraulic chambers 6 and 7, and from then on, the first output boat P, Similar operations are repeated as the output oil pressure increases, and as a result, the first output port P
1 output hydraulic pressure can be proportionally reduced and transmitted to the left rear wheel brake Br.

During this time, the piston 19 reciprocates left and right.

In this case, the pressure at which the pressure reducing valve 51 starts reducing the pressure is determined by the cross section 13-area A and the air pressure of the air spring 22, and the air pressure changes depending on the loaded weight of the vehicle, so it is possible to approximate the ideal braking. can. Further, the pressure reduction ratio is approximately determined by the ratio between the cross-sectional area (B-A) and the cross-sectional area A.

On the other hand, if the output oil pressure of the second output port P2 rises above a predetermined value, the second pressure reducing valve 52 operates in the same way as the first pressure reducing valve 51, and the output oil pressure is proportionally applied to the right rear wheel brake Br2. Reduce pressure and transmit.

By the way, both pressure reducing valves 5. ．． When 52 is activated, each valve body 9,9
Generally, there is a slight error in the operating timing and operating stroke, and depending on these errors, the balance lever 13 tilts around the protrusion 19a of the piston 19, and the pressure in the pressure chamber 20 of the cylinder portion 14b is distributed between the two valve bodies. 9,9, so that both pressure reducing valves 51.5□
The pressure at which the decompression action starts is surely balanced.

14- On the other hand, if a failure such as air leakage occurs in the 22 air spring systems, the first. Air pressure is temporarily confined in the pressure chamber 20 by the cooperation of the second control valves 361 and 362. −'
(When the oil pressure in the output oil pressure chamber 7 reaches a predetermined value during braking in steps 1 to 1, a pressing force acting on the valve bodies 9, 9 in the right direction in the figure is applied to the valve bodies 9, 9 of the pneumatic pressure contained in the pressure chamber 20. The valve bodies 9, 9 are moved to the right in the figure by overcoming the force of half of the biasing force exerted by the radiator, and each valve part 9h is seated on the valve seat 8, and as described above, the first. The output oil pressure of the second output port P, P2 is on the left.

The pressure can be proportionally reduced and transmitted to the right rear wheel brakes Br, Br2. In this case, the depressurization start pressure is determined by the set load of the valve spring 38 of the second control valve 362, so the pressure is low, but it is safe because the locking phenomenon of the rear wheels is reliably prevented.

FIG. 2 shows a modification of the sealing valve mechanism 31, in which the valve surface 40 of the mechanism 31 has an inlet 41 on the air spring 22 side whose center line coincides with the center line of the valve surface 40, and an inlet 41 on the air spring 22 side, and It has an outlet 42 on the side of the pressure chamber 20 whose center line is offset outward by a predetermined distance from the center line of the surface 40, and a valve chamber 43 that communicates between these outlets 41 and 42. The valve chamber 43 consists of a small diameter part 44 on the inlet 41 side and a large diameter part 45 on the outlet 42 side, and the large diameter part 45 has a slidable valve seat body 48 having a valve hole 46 in the center, A first spring 50° is housed to urge the valve seat body 48 toward the stepped portion 49 between the small diameter portions 45 and 44, and the small diameter portion 44 includes a valve body 51 made of a steel ball, and the valve body 51 made of a steel ball. A second spring 502 that urges the body 51 toward the valve seat body 48 is housed. A valve hole 46 is located in the center of the end wall with an outlet 42.
A pin-shaped protrusion 52 is provided which faces the valve body 51 at a predetermined distance.

The set load of the first spring 501 is such that when the air pressure in the air chamber 23 in the air spring 22 acts on the valve seat body 48 and the valve body 51, the valve seat body 48 and the valve body 51 immediately slide to the left in the figure, causing the valve body 51 to follow it. The valve hole 4 is abutted against the pin-shaped protrusion 52.
It is set low to open 6.

The set load of the second spring 502 is set so that if the air pressure generated in the pressure chamber 20 acts on the valve body 51 at the start of the depressurization operation when there is one occupant in the vehicle, the air pressure is immediately separated from the valve seat body 4B. 1 spring 501 is set higher than that of spring 501.

In the above configuration, if the air spring 22 is normal, its air pressure acts on the small diameter portion 44 of the valve chamber 43, slides the valve seat body 48 to the left in the figure, opens the valve hole 46, and causes the pressure chamber 20 to open.
Air pressure is introduced into the first . Second pressure reducing valve 5
The depressurization start pressure of 1.52 is determined according to the loaded weight of the vehicle.

On the other hand, if the air spring 22 system fails, the air pressure is temporarily confined in the pressure chamber 20 by the cooperation of the valve seat body 46, the valve body 51, and the second spring 502, and as a result, the first ．． Second pressure reducing valve5. ．． 52 can be determined.

Note that the air pressure of the air spring 22 may be converted into oil pressure, and the oil pressure may be introduced into the pressure chamber 20 via the sealing valve mechanism 31.

As described above, according to the present invention, the air spring of the suspension system is used to determine the pressure at which the pressure reducing valve starts reducing the pressure according to the loaded weight of the vehicle, thereby making it possible to approximate ideal braking. In addition, even if the air spring system fails, the sealing valve mechanism allows the residual pressure from the air spring to be used to determine the pressure at which the pressure reducing valve starts reducing the pressure, thereby reducing the hydraulic pressure to the rear wheel brakes. It is possible to reliably prevent the ring lock phenomenon and ensure safety.

18-

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a modification of the sealing valve mechanism. B r,, 13 r2-=Left, right rear wheel brake, L,
. 1.2 , L, f , L, r, L, , f , L2r-=
Oil passage, AI... mask cylinder, p,, p2... +, s second output port, 5, . 52...1st. 2nd pressure reducing valve, 16... pneumatic path as pressure path, 22... air spring, 31... sealing valve mechanism 19- 278-

Claims (1)

[Claims] A pressure reducing valve capable of proportionally reducing and transmitting the output hydraulic pressure of the output port to the rear wheel brake is interposed in the oil passage connecting between the output port of the mask cylinder and the rear wheel brake,
The air spring of the suspension device, which determines the pressure at which the pressure reducing valve starts reducing according to the loaded weight of the vehicle, is used to reduce the pressure via a pressure path so that the pressure of the air spring urges the pressure reducing valve in the opening direction. When the air spring is normal, the pressure is transmitted to the pressure reducing valve, but when the air spring is in failure, the pressure is transmitted to the pressure reducing valve side so that the starting pressure of the pressure reducing valve can be determined. A brake hydraulic control device for a vehicle comprising a sealing valve mechanism interposed in the pressure path to temporarily seal the pressure.