JPS6015499B2 - Vehicle brake hydraulic control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a two-system brake hydraulic control system for a vehicle, particularly a four-wheeled vehicle, in particular a system for controlling first and second output boats of a master cylinder and left and right rear wheel brakes. First and second pressure reducing valves capable of proportionally reducing and transmitting the output hydraulic pressure of the first and second output boats to the left and right rear wheel brakes, respectively, are installed in each independent oil passage connecting between them. The present invention relates to a device that prevents a rear wheel locking phenomenon caused by a reduction in rear wheel load due to braking.

In this type of device, the applicant bridges a balance lever between two parallel valve bodies of the first and second pressure reducing valves, and inserts the balance lever into the lever housing that accommodates the balance lever. A spring is provided between the balance lever and the bar housing to cause braking when both the oil passages are normal. It is proposed to provide a clearance that allows the balance lever to move at times, and at the same time suppresses the movement of the balance lever to a certain angle during braking when either of the oil passages fails. are doing.

In this device, during braking when both hydraulic circuits are normal, even if there is an error in the actuation timing and actuation stroke of the valve bodies of both pressure reducing valves, the spring will not spring due to the movement of the balance lever. The force is distributed evenly to both valve bodies, so the pressure at which the pressure reduction action starts for both pressure reducing valves can always be balanced, and even with the left and right rear wheel brakes, which have different oil pressure systems, the braking forces are balanced with each other and the vehicle is maintained. The braking position of the pressure reducing valve in the normal system can be stabilized, and when braking when one hydraulic circuit breaks down, the balance lever increases the scale angle and locks directly to the lever housing, so that the pressure reducing valve in the normal system is It is possible to immediately stop the pressure reduction function and increase the braking force of the rear wheel brake in the normal system to the maximum extent, and it is possible to prevent excessive or insufficient braking force due to the above-mentioned failure. The present invention further improves the above-mentioned device, and when the balance lever rotates greatly due to a failure in one hydraulic circuit, the corner of the balance lever immediately bites into the inner surface of the lever housing, and the balance lever's coin holder is fixed. It is an object of the present invention to provide a highly durable device which is reliable in its action, has a balance lever and a lever housing that can be used as is without having to be replaced even after a faulty circuit is repaired, and has excellent vibration resistance. purpose.

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
First, in FIG. 1, M denotes a known tandem master cylinder, Bna, Bna2, which is operated by a brake pedal 1.
Br, , Br2 indicate left and right front wheel brakes, and Br2 indicate left and right rear wheel brakes, respectively.

In addition, 2 is a valve box (not shown) that is fixed to a proper place on the vehicle body.
On the outside thereof, there is a first inlet 3 connected to the first output boat P of the master cylinder M via an oil passage L, and an oil passage L.
The first and second outlets 4, 42 are connected to the left front brake Bna and the right rear brake Br2 through the oil passages L and r, respectively, and the master cylinder M is connected to the master cylinder M through the oil passage. Second inlet 3 connected to second output boat P2
2 and third and fourth outlets 43 and 44, which are connected to the right front wheel brake Bna 2 and the left rear wheel brake Br, respectively, via an oil passage Lf and an oil abbreviation -r,
First and second pressure reducing valves 5, 52 are installed in the valve box 2 to control the flow between the first inlet 3 and the second outlet 42, and the flow between the second inlet 32 and the fourth outlet 44, respectively. are installed in parallel. The first pressure reducing valve 5 has an input hydraulic chamber 6 and an output hydraulic chamber 7 communicating with the first inlet 3 and the second outlet 42, respectively, and an elastic material such as rubber installed between the two hydraulic chambers 6 and 7. A valve seat 8, a valve body 9 that cooperates with the valve seat 8 to allow communication and isolation between the two hydraulic chambers 6 and 7, and a valve seat provided striped between the valve seat 8 and the valve body 9. 8 and a coil spring 10 holding the coil spring 8.

The valve body 9 has a piston-shaped valve portion 9 that cooperates with the valve seat 8 at the tip of a valve village 9a that encloses the valve hole of the valve seat 8 and the input hydraulic pressure chamber 6.
a and an inner protruding shaft 9c protruding from its outer end surface. The square shaft 9b and the protruding shaft 9c are arranged in the output hydraulic chamber 7, and the protruding string 9c is supported in a support cylinder 16 disposed in the output hydraulic chamber 7. This spinal column 16 prevents the valve body 9 from becoming troublesome and limits its opening limit. Second
The pressure reducing valve 52 connects the input and output hydraulic chambers 6, 7 to the second inlet 32,
It has the same structure as the first pressure reducing valve 5 described above, except that it is fitted to the fourth outlet 44, respectively, and parts corresponding to the first pressure reducing valve 5 are given the same reference numerals.

The first and third brakes connected to the front wheel brakes B〆, , B〆2
The outlets 4, 43 are respectively connected to the first and second pressure reducing valves 5, .
It communicates directly with the input hydraulic chambers 6, 6 of 52.

Further, a cylindrical lever housing 12 adjacent to the input hydraulic chambers 6, 6 of the first and second pressure reducing valves 5, 52 is fixed to the valve case 2 by bolts 21.
, there is a cylindrical cup-shaped balance lever 13 that extends between the ends of the two valve bodies 9a, 9a of both pressure reducing valves 5, 52 that enter there, and that Bento pestle 9a
, 9a are housed therein.

Due to the elastic force of this spring 15, each valve portion 9b of both valve bodies 9, 9
are normally held at positions separated from the valve seat 8. The balance lever 13 has a shallow cup shape so as to accommodate the fulcrum member 14, and a spherical recess 13d is formed at the center of the inner bottom surface.

On the other hand, the fulcrum member 14 similarly has a shallow cup shape so as to be able to receive the operating end of the spring 15, and a spherical protrusion 14a protruding from the center of its outer bottom surface engages with the spherical recess 13a. Therefore, the support point n of the fulcrum member 14 against the balance lever 13, that is, the pressing point of the spring 15 against the balance lever 13 is between the contact points 1 and m between the balance lever 13 and the two valve punches ga and 9a. It is placed at the midpoint of the straight line x connecting.

As a result, the distances from the fulcrum n to the respective balance points 1 and m are kept equal regardless of the mirror movement of the balance lever 13, so that the rock force of the spring 15 is transferred to both valve bodies 9 and 9 through the balance lever 13. 9
can be made to act equally. A play space S is provided between the opposing peripheral surfaces of the cylindrical cup-shaped balance lever 13 and the cylindrical lever housing 12 to allow the balance lever 13 to move within a specified angular range. The width of the outer circumferential surface is set to be one height shorter than the outer diameter (preferably at least 1'a) so that it is locked to the lever housing 12 as soon as the lever reaches its working limit. .

In addition, the balance lever 13 has an annular elastic member 20 such as a highly flexible ring in an annular groove 19 on its outer periphery, and this elastic member 20 lightly contacts the inner peripheral surface of the lever housing 12 to maintain balance. The lever 13 is supported in a floating manner so as to allow its movement.

Further, a sufficient clearance S2 is provided between the opposing surfaces of the balance lever 13 and the fulcrum member 14 to allow the balance lever 13 to pivot.

In the above-described foundation, the hardness of at least the corner portion of the balance lever 13 facing the inner surface of the lever housing 12 and the valve body support portion adjacent to the corner portion and in contact with both the valve bodies 9, 9 is the same as that of the bar housing 12. The hardness is higher than the inner surface,
The present invention is characterized by this point and the point that the balance lever 13 is supported in a floating manner by the elastic member 20 as described above.

Specifically, in the example shown in FIG. 1, the lever housing 12 is made of an AI alloy, while a hard member 13a made of cast iron or other iron-based material is wrapped around the outer periphery of the N-alloy balance lever 13 and is press-fitted. The above-mentioned difference in hardness is obtained by fixing the hardness. Next, to explain the operation of this embodiment, when the brake pedal 1 is depressed while the vehicle is running and the master cylinder M is activated,
If hydraulic pressure is output from the first and second output boats P, , P2), the output hydraulic pressure of the first output boat P, is output from the oil path L,
, the input hydraulic chamber 6 of the first pressure reducing valve 5 and the oil passage L, to the left front wheel brake Bna, and from the hydraulic chamber 6 to the right rear wheel via the corresponding output hydraulic chamber 7 and oil passage Lr. The signals are transmitted to the brakes Br2 to operate them.

On the other hand, the output oil pressure of the second output boat P2 is sent to the right front wheel brake Bna 2 through the oil path L, the input oil pressure chamber 6 of the second pressure reducing valve 52, and the oil path 2, and is also selected from the above-mentioned oil pressure chamber 6. Left rear wheel brake B via output hydraulic chamber 7 and oil passage Lr
r, respectively to activate them. When the output oil pressures of the first and second output boats P, P2 of the master cylinder M rise above a predetermined value, the first and second pressure reducing valves 5
, , 52 begin to control the hydraulic pressure of the rear wheel brakes Br, , Br2, respectively, and their functions will be explained in detail next.

First, due to the increase in the output oil pressure of the first output boat P, the first
When the pressure reducing valve 5 enters and the hydraulic pressure in the output hydraulic chambers 6 and 7 reaches a predetermined value, the hydraulic pressure acting on the valve body 9 causes a rightward pressing force (input to the base section mirror A of the valve punch ga, and the output hydraulic pressure This corresponds to the product of the oil pressure in chambers 6 and 7.

) overcomes the eccentric force of the spring 15 on the valve body 9 (one-half force of the set load of the spring 15) and moves the valve body 9 to the right in the figure, causing the valve portion 3b to move toward the valve seat 8. The output hydraulic chambers 6 and 7 are shut off. After that, if the output oil pressure of the first output boat P further increases, the leftward pressing force of the valve body 9 due to the oil pressure of the input oil pressure chamber 6 (cross-sectional area B of the valve part 9b
and the section mirror A multiplied by the oil pressure in the input oil pressure chamber 6. ) overcomes the rightward pressing force of the valve body 9 due to the hydraulic pressure of the output hydraulic chamber 7 (approximately equivalent to the cross-sectional area B multiplied by the hydraulic pressure of the output hydraulic chamber 7), and pushes the valve body 9 to the left. , the valve part 9b is separated from the valve seat 8, and the pressure between the two hydraulic chambers 6 and 7 is increased again, so that the output hydraulic pressure chamber 7 is increased in pressure. The rightward pushing force increases immediately, and the valve body 9 is shifted to the right again to cut off the communication between the two hydraulic chambers 6 and 7. Thereafter, as the output hydraulic pressure of the first output boat P increases, the same operation occurs. are repeated, and as a result, the output hydraulic pressure of the first output boat P can be proportionally reduced and transmitted to the right rear wheel brake B2.In this case, the pressure at which the pressure reducing valve 5 starts to reduce the pressure is Section book A
It is determined by the biasing force of the spring 15 applied to the valve body 9, and its pressure reduction ratio is approximately determined by the ratio of the cross-sectional area (B-A) to the cross-sectional mirror A.

On the other hand, if the output oil pressure of the second output boat P2 rises above a predetermined value, the second pressure reducing valve 52 operates in the same way as the first pressure reducing valve 5, and the output oil pressure is proportional to the left rear wheel brake Br. The pressure is reduced and transmitted. By the way, both pressure reducing valves 5, 52
During operation, there is generally a slight error in the operating timing and operating stroke of each valve body 9, and depending on these errors, the balance lever 13 is controlled within the range of the play force S, and even during the subsequent shift. As mentioned above, since the distances from the fulcrum n to the contact points 1 and m are kept equal, the balance lever 13 can always equally distribute the elastic force of the spring 15 to both the valve bodies 9, 9. As a result, the pressure reduction start pressures of both pressure reducing valves 5, 52 are reliably balanced.

There is no failure in all hydraulic circuits, and all brakes are closed.
,B〆2 and Br, ,B2 are operating normally, but now suppose an oil leakage failure occurs only in the oil line of the first generation power port P, Assuming that the brake B-na and right rear wheel brake B-na 2 become inoperable,
During braking, the first pressure reducing valve 5 becomes inoperable, while the second pressure reducing valve 52 can operate, so as mentioned above, the valve body 9 of the second pressure reducing valve 52 is activated as the master cylinder M operates.
A rightward pressing force due to hydraulic pressure acts on the balance lever 13, which causes the balance lever 13 to move significantly as shown in FIG.
Both diagonal corners of the lever 13, which tend to rise, come into pressure contact with the inner surface of the lever housing 12.

Then, since the corner portion of the balance lever 13 is made harder than the inner surface of the lever housing 12 as described above,
Both corners are well-bitten into the inner surface of the lever housing 12, and the balance lever 13 is reliably locked to the housing 12. Therefore, the valve body 9 of the second pressure reducing valve 52 is immediately prevented from petrifying, and the input and output hydraulic chambers 6 and 7 are maintained in a fully balanced state. That is, since the second pressure reducing valve 52 stops its pressure reducing function, the left rear wheel brake Br directly receives the output oil pressure from the second output boat P2 and exerts its maximum braking force. Since the width of the outer circumferential surface of the balance lever 13 is set to be significantly shorter than the outer diameter, when the balance lever 13 is tilted and its corner comes into contact with the inner surface of the lever housing 12, it immediately A twisting phenomenon occurs and the balance lever 13 is securely stopped.

As described above, according to the present invention, a cylindrical cup-shaped balance lever is bridged between two parallel valve bodies of both pressure reducing valves, and the balance lever is placed in a cylindrical lever housing that accommodates the balance lever. A spring is installed to determine the pressure at which the pressure reduction action of both the pressure reducing valves starts by springing the valve bodies in all directions through the spring, and a spring is provided between the opposing circumferential surfaces of the balance lever and the bar housing. When braking when the oil passage is normal, the balance lever is allowed to move backward, and when braking when either side adjacent to the oil has failed, the mirror movement of the balance lever is suppressed to a certain angle. The balance lever is configured such that the width of the outer circumferential surface thereof is significantly shorter than the outer diameter so that the balance lever is immediately fixed to the lever housing when the balance lever is moved at the certain angle. Therefore, during braking when both hydraulic circuits are normal, even if there is an error in the operating timing and operating stroke of the square bodies of both pressure reducing valves, the elastic force of the spring is balanced by the movement of the balance lever. It is distributed evenly to the valve body, so the pressure at which the pressure reduction action starts for both pressure reducing valves can always be balanced, and even with the left and right rear wheel brakes, which have different hydraulic systems, the braking force is balanced with each other and the braking posture of the vehicle is adjusted. It can be stabilized.

In addition, when braking is performed when one of the oil passages is out of order, the balance lever is immediately attached to the lever housing by simply moving the above-mentioned certain angle, and therefore, the balance lever cannot be moved to the lever until the locking state is achieved. Compared to a structure that requires sliding a predetermined amount against the housing, the effect of stopping the pressure reducing function of the pressure reducing valve in a normal system can be obtained quickly.
The braking force of the rear wheel brake can be increased to the maximum level from the initial level of braking, and it is possible to prevent excessive or insufficient braking force due to the above-mentioned failure. Furthermore, the balance lever is shaped like a cylindrical cup,
In addition, since the lever housings are each formed into a cylindrical shape, the balance lever can be made thin and lightweight while achieving a certain level of strength.Moreover, the balance lever can be rotated around its central axis. However, there is no change in the proper bridging state for both valve bodies, so there is no need to prevent the balance lever from rotating, and it is sufficient to simply accommodate the balance lever and spring in the lever housing, making assembly extremely simple and easy.

In particular, at least a corner portion of the balance lever that faces the inner circumferential surface of the lever housing, and a valve body support portion adjacent to the corner portion that is connected to both the valve bodies, are provided with a larger area than the lever housing. Since a hard material with high hardness is embedded, the above-mentioned corner part of the balance lever will hardly wear out even if it bites into the inner surface of the lever housing. Therefore, the balance lever and lever housing can be used without any trouble even after repairing a faulty circuit. In other words, there is no change in the balance lever's bending even in the event of a failure. In addition, the above-mentioned valve body abutment part of the balance lever hardly wears due to friction with the valve body, and the relative positional relationship between the balance lever and the valve body does not change, so the operating characteristics of both pressure reducing valves can be maintained for a long time. It can be stabilized over a period of time. Since the corner portion of the balance lever and the rear portion of the valve body can be reinforced by a common hard member, the structure is simple and can contribute to cost reduction. Furthermore, since an elastic member is inserted into the gap between the facing peripheral surfaces of the lever housing and the balance lever to support the balance lever in a floating manner, even when the vibration of the vehicle occurs, the balance lever vibrates and the hard reinforced portion of the lever This not only prevents the lever from hitting the inner wall of the lever housing, thereby preventing the occurrence of knocking noise, but also prevents damage to the inner wall of the lever housing from causing a change in the balance lever's performance. control characteristics can be maintained.

[Brief explanation of the drawing]

The drawings show an embodiment of the device of the present invention, and FIG. 1 is a vertical sectional plan view, and FIGS. 2 and 3 are views of the roller and m-
FIG. 4, which is a cross-sectional view taken along the m-line, is a diagram showing the operation of essential parts during braking in the case of a failure in one of the hydraulic systems. Br,... Left rear wheel brake, Br2... Right rear wheel brake, L,, L, L, r, L2r... Oil path, M... Master cylinder, P,... ...First output boat, P2...Second output boat, S. ...play space, 5
......First pressure reducing valve, 52......Second pressure reducing valve, 9
... Valve body, 12 ... Lever housing, 13 ... Balance lever, 15 ... Spring, 2
0...Elastic member. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1 The first and second output ports of the master cylinder and the left
A first oil passage capable of proportionally reducing and transmitting the output hydraulic pressure of the first and second output ports to the left and right rear wheel brakes, respectively, to each independent oil passage connecting the right rear wheel brake. In the one in which the first and second pressure reducing valves are respectively interposed,
A cylindrical cup-shaped balance lever is bridged between two parallel valve bodies of both pressure reducing valves, and both valve bodies are opened via the balance lever in a cylindrical lever housing that accommodates this balance lever. A spring that springs in the direction to determine the pressure at which the pressure reduction action of both the pressure reducing valves starts is compressed, and the spring is compressed between the opposing peripheral surfaces of the balance lever and the lever housing, and is provided between the opposing circumferential surfaces of the balance lever and the lever housing to prevent the pressure in the balance during braking when both the oil passages are normal. A clearance is provided to allow the lever to tilt and to suppress the tilting of the balance lever to a certain angle during braking in the event of a failure in either of the oil passages, and an elastic member is provided in the clearance. The balance lever is supported in a floating manner by being inserted, and the balance lever is
embedding a hard member that is harder than the lever housing at least in a corner portion facing the inner circumferential surface of the lever housing, and in a valve body contacting portion adjacent to the corner portion and in contact with both the valve bodies; Furthermore, the balance lever is configured such that the width of the outer circumferential surface of the balance lever is set to be significantly shorter than the outer diameter so that the balance lever is immediately locked to the lever housing when the balance lever is tilted at the predetermined angle.