JPH0611266Y2 - Load-sensing brake fluid pressure controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to a brake fluid pressure control device, and in particular, the fluid pressure supplied from a fluid pressure source to a wheel cylinder is reduced according to the magnitude of the load on a wheel. The present invention relates to a load-sensing brake hydraulic pressure control device.

2. Description of the Related Art Brake fluid pressure control devices of this type are already known. The device described in Japanese Patent Publication No. 58-53620 is an example. In this device, as shown in FIG. 3, a coil-shaped spring 100 is used as a suspension spring, and a cup-shaped member 104 attached to a sprung member 102 is arranged between the unsprung member and the cup-shaped member 104. The upper end of the suspension spring 100 is supported and the load of the suspension spring 100 is received. The load received by the cup-shaped member 104 is transmitted to the elastic body 110 via the ball 106 and the plate member 108, and further, from the elastic body 110, the sprung member 1 is transmitted.
02 is transmitted to a housing 112 supported by 02 and a bottomed cylindrical member 114 fitted in the housing 112 so as to be vertically slidable. The tubular member 114 is a valve piston 118 of the pressure reducing valve 116 fixed to the sprung member 102.
And the elastic body 110 is engaged with the housing 1.
12 and the tubular member 114, a load proportional to the contact area between them is applied, and the load transmitted to the tubular member 114 is further controlled by the control spring 120 provided concentrically with the pressure reducing valve 116 in the housing 112. It will be reduced and will act in the direction of pushing the valve piston 118 into the valve body 122. This load is set so that the pressure reducing valve reduces the pressure when the hydraulic pressure of the master cylinder, which is the hydraulic pressure source, reaches a predetermined magnitude corresponding to the wheel load. The hydraulic pressure supplied to the wheel cylinder of the wheel corresponding to 100 will be controlled to a magnitude corresponding to the wheel load.

According to this device, since the urging force is applied to the valve piston 118 with the load of the suspension spring 100 being reduced at a constant rate, the valve piston 11
The diameter of the pressure reducing valve 116 can be reduced, and the pressure reducing valve 116 can be reduced in weight and size, and the brake fluid consumption in the pressure reducing valve can be reduced.

However, in this device, since the control spring 120 is provided concentrically with the pressure reducing valve 116 in the housing 112, its arrangement is not easy, and the control spring 120 and peripheral members are not provided. There was a problem that the degree of freedom in design was small.

Means for Solving the Problems In order to solve the above problems, the present invention provides a load-sensing brake fluid pressure control device, comprising: (a) a valve piston protruding from a valve body to the outside, and a vehicle suspension. A pressure reducing valve that is attached to one of an unsprung member and an unsprung member that are connected to each other by a spring, and that reduces the brake fluid pressure supplied from the fluid pressure source to the wheel cylinder of the wheel corresponding to the suspension spring, (b ) An input member that is provided between the pressure reducing valve and the suspension spring and receives a load of the suspension spring, and (c) is attached to a member of the sprung member and the unsprung member on the side where the pressure reducing valve is provided. , Part of the load received by the input member is transferred to that member, and the rest is transferred to the valve piston in the direction in which the pressure reduction start hydraulic pressure of the pressure reducing valve rises. (E) a lever that is rotatably supported around a single axis by a member on the side where the pressure reducing valve is attached, and that transmits force between the force divider and the valve piston. )
The lever includes an elastic member that applies a force in a direction in which the force acting from the lever to the valve piston is reduced on a line of action different from the line of action of the force from the lever to the valve piston.

In the load-sensing brake hydraulic pressure control device configured as described above, the lever transmits the force between the elastic member, the valve piston of the pressure reducing valve, and the force divider, and the force of the elastic member is transmitted. Acts on the lever in a direction in which the force acting on the valve piston from the lever decreases on a line of action different from the line of action of the force from the lever to the valve piston, which causes the elastic member to move away from the pressure reducing valve. It is provided in the position. Therefore, according to the present invention, as compared with the case where the elastic member is provided concentrically with the pressure reducing valve, that is, when both are arranged so that the lines of action of force coincide with each other as in the conventional case, the elastic member and the peripheral member are arranged. The effect of increasing the degree of freedom of design is obtained.

Further, for example, as will be described in detail in the embodiments, when the present invention is carried out in a mode that positively utilizes the boosting action of the lever, the elastic member is designed so that the force applied to the lever is small. As a result, the effect that the elastic member can be made small is obtained, and if the elastic member is implemented in a manner in which its elastic force (load) can be adjusted, the adjustment can be performed. It is possible to obtain the effect that it can be easily performed without being hindered by the pressure reducing valve.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a view showing a main part of a load sensing type brake hydraulic pressure control device according to an embodiment of the present invention, in which 10 is a frame which is a sprung member. On the lower surface of the frame 10, a large-diameter piston 12 having a bottomed cylindrical shape is provided as a rubber damper 1.
It is attached through 4. A flange portion 16 extending outward in the radial direction is provided on the peripheral edge portion of the opening of the large-diameter piston 12.
Is formed, and is attached to the frame 10 via the damper 14 at the flange portion 16.

A proportioning valve (hereinafter abbreviated as P valve) 20 is fixedly housed in the large-diameter piston 12. The valve body 22 of the P valve 20 is provided with a port 24 (not shown) connected to a brake master cylinder, which is a hydraulic pressure source (not shown), and a port (not shown) connected to a wheel cylinder, and also has a bottomed step opening downward. A through hole 26 is formed. The opening of the stepped hole 26 is
The plug 28 is closed by fitting in a liquid-tight manner so that it cannot be pulled out, and a fluid pressure chamber 30 is formed in the valve body 22, and the port 24 is connected to the fluid pressure chamber 30 by a fluid passage 32. Although not shown in the figure, the port connected to the wheel cylinder is also connected to the hydraulic chamber 30 by a liquid passage.

A valve piston 36 is fitted in the hydraulic chamber 30 so as to be slidable in the axial direction. The lower end portion of the valve piston 36 is sealed by the cup seal 38 and protrudes to the outside of the valve body 22 to be exposed to the outside air, but the upper end portion is located in the hydraulic chamber 30, and the valve element 40 is provided at the front end portion thereof. Are integrally formed. The valve piston 36 is always kept at a position separated from the rubber valve seat member 44 held by the valve body 22 by the compression coil spring 42, and the hydraulic pressure supplied from the brake master cylinder is directly supplied to the wheel cylinder. It is supposed to be done.
A ball 46 is rotatably held at the lower end of the valve piston 36.

A through hole 50 is provided in the valve body 22 in parallel with the valve piston 36, and a compression coil spring 52 as an elastic member is accommodated therein. A nut 54 is screwed into the upper end opening of the through hole 50, an adjusting bolt 56 is screwed into the nut 54, and is fixed by a lock nut 58. The lower end of the bolt 56 has a through hole 5
0, and the upper end of the spring 52 is received by a bolt 56 via a spring receiver 60. The lower end of the spring 52 projects from the through hole 50,
It is engaged with a lever 62 arranged in the large-diameter piston 12 via a spring receiver 64.

The lever 62 has a longitudinal shape and is arranged so as to face the P-valve 20 and the spring 50, respectively, and to extend in a direction substantially perpendicular to the respective center lines thereof.
It is rotatably supported around the horizontal axis by the peripheral wall of the large-diameter piston 12 at the end close to the portion facing 0. The lever 62 faces the valve piston 36 at its intermediate portion and is engaged with the lower end portion of the spring 52 at its free end portion.
Is urged in a direction away from the valve piston 36, and the distance between the lever 62 and the valve piston 36 is changed by adjusting the bolt 56. The valve body 22 is urged upward by the spring 52, and the C-shaped retaining ring 65
This prevents the large-diameter piston 12 from coming out, and the position is fixed.

A cylindrical member 66 having a bottom is slidably fitted to the large-diameter piston 12. A flange portion 68 extending outward in the radial direction is provided at the peripheral edge portion of the opening of the cylindrical member 66, and a coil-like suspension vertically arranged on the lower surface of the flange portion 68 via an insulator 70. The upper end of the spring 72 is seated. The lower end of the suspension spring 72 is seated on an unsprung member (not shown), and the load of the suspension spring 72 is applied to the cylindrical member 66 so that the bottom wall of the suspension member 72 contacts the bottom wall of the large-diameter piston 12. Being energized. The cylindrical member 66 functions as an input member. A peripheral portion of the damper 14 is engaged with the flange portion 68 to prevent intrusion of mud, water, etc. between the large-diameter piston 12 and the cylindrical member 66. . A rubber damper 74 is fixed to the lower surface of the cylindrical member 66 so as to prevent the suspension spring 72 from being damaged due to excessive compression by abutting against a stopper fixed to the axle housing.

A through hole 76 is formed in the bottom wall of the large-diameter piston 12 concentrically with the valve piston 36.
A small-diameter piston 78 is fitted in 6 so as to be slidable in the axial direction. The small-diameter piston 78 has a stepped shape, and its large-diameter portion 8
When 0 contacts the stopper 82 extended inward from the upper opening of the through hole 76, the movement in the direction toward the valve piston 36 is restricted. In addition, the small diameter portion 84 projects into the large diameter piston 12,
A ball 86 is held at its tip, and the lever 6 urged by the spring 52 is held by the ball 86.
2 makes contact with each other and urges the small-diameter piston 78 in a direction away from the stopper 82.

A rubber elastic body 90 is arranged between the bottom wall of the large-diameter piston 12 and the bottom wall of the cylindrical member 66. The cylindrical member 66 moves in the axial direction and applies the load received from the suspension spring 72 to the elastic body 90,
Contacts the lower surfaces of the large-diameter piston 12 and the small-diameter piston 78, and applies the force applied by the cylindrical member 66 to both pistons 12, 78 by dividing the force by the contact area ratio.
The force applied to the large diameter piston 12 is received by the frame 10, while the force applied to the small diameter piston 80 is transmitted to the lever 62. The large-diameter piston 12, the small-diameter piston 78, the elastic body 90, etc. constitute a force dividing device.

The set load of the spring 52 is set when the vehicle is lightly loaded (when two passengers are seated in the front seat and no luggage is loaded. At this time, the load applied by the suspension spring 72 to the cylindrical member 66 is set as the first set load. .) Between the valve piston 36 and the lever 62.
A gap β ₁ slightly larger than the stroke α (0.8 mm in the present embodiment) of the valve piston 36 required for seating on the vehicle is formed, and the large diameter portion 80 of the small diameter piston 78 is formed.
It is set so that a minute gap β ₂ (0.1 mm in this embodiment) is formed between the stopper 82 and the stopper 82. The spring constant of the spring 52 is equal to that of the suspension spring 72.
Is increased to a second set load that is slightly larger than the first set load, the large diameter portion 80 is allowed to contact the stopper 82. When contacted, the gap between the lever 62 and the valve piston 36 is provided at a position smaller than the stroke α of the valve piston 36.

In the hydraulic pressure control device configured as described above, when the load of the suspension spring 72 is smaller than the first set load, the gap between the valve piston 36 and the lever 62 is larger than β ₁ , and the master cylinder hydraulic pressure is Rise,
Even if the valve piston 36 moves until the valve element 40 is seated on the valve seat member 44, the valve piston 36 does not contact the lever 62 and the P valve 20
Reduces the hydraulic pressure supplied from the master cylinder at a constant ratio and supplies the hydraulic pressure to the wheel cylinders regardless of the vehicle load. Further, the small diameter piston 78 is separated from the stopper 82 by a distance larger than β ₂ .

When the load of the suspension spring 72 is the first set load, the gap between the lever 62 and the valve piston 36 becomes β ₁ , and the gap between the large diameter portion 80 of the small diameter piston 78 and the stopper 82 becomes β ₂ . Then, when the load of the suspension spring 72 is larger than the first set load and smaller than the second set load, the size of the gap between the small diameter piston 78 and the stopper 82 becomes smaller than β ₂ , and as the small diameter piston 78 moves. Lever 62 is spring 5
By being rotated against the biasing force of 2, the distance between the valve piston 36 and the lever 62 becomes smaller than β ₁ . When the load of the suspension spring 72 is greater than or equal to the second set load, the large diameter portion 80 of the small diameter piston 78 is
Comes into contact with the stopper 82, and further movement is blocked. In this state, the size of the gap between the lever 62 and the valve piston 36 is (β ₁ −β ₂ ), and the P valve 2
In order for 0 to perform the depressurizing action, the valve piston 36 moves the small diameter piston 80 to the elastic body 9 by an amount slightly smaller than β _2.
It is necessary to push it into 0.

Even if the small-diameter piston 78 comes into contact with the stopper 82 and is prevented from moving, the suspension spring 72 remains in the elastic body 90.
Is applied, the large-diameter piston 12 and the small-diameter piston 7
Loads are transmitted to 8 and 8, respectively. Therefore, even if the amount of pushing of the small diameter piston 78 by the valve piston 36 is constant, the pushing force overcomes the force (input load) applied from the elastic body 90 to the small diameter piston 78 in response to the load of the suspension spring 72. A force is required, and the P valve 20 will perform a pressure reducing action corresponding to the loaded load.

However, since the pushing amount of the small-diameter piston 78 when the depressurizing action is performed is small, even if the hardness of the elastic body 90 changes due to temperature change or the like, the P valve 20 changes as described below. Less affected,
It is possible to obtain stable control characteristics. When the valve piston 36 is always in contact with the lever 62 without providing the stopper 82, the input load f acting in the direction of pushing the valve piston 36 into the valve body 22 is expressed by the following equation (1).

However, F: load of suspension spring 72 F _s : set load of spring 52 S ₁ : cross-sectional area of large-diameter piston 12 S ₂ : cross-sectional area of small-diameter piston 78 ₁ : spring from support portion of large-diameter piston 12 of lever 62 the distance to the engagement portion of the 52 _2: distance Δf from the support portion by the large-diameter piston 12 of the lever 62 to the contact portion between the valve piston 36, when the valve piston 36 pushes the small diameter piston 78 in the elastic member 90 The stroke of the valve piston 36 until the valve element 40 is seated on the valve seat member 44 when the valve piston 36 does not have the stopper 82 and the valve piston 36 is always in contact with the lever 62. Since the small-diameter piston 78 must be pushed into the elastic body 90 by an amount equal to α, Δf is expressed by the following equation (2).

Δf = k · α (2) However, k: spring constant of the elastic body 90 On the other hand, in the device of this embodiment, the pushing amount is almost β ₂ , and Δf is expressed by the following equation (3). It

Δf = k · β ₂ (3) β ₂ is smaller than α, and Δf, and thus the input load f represented by the above formula (1), is less affected by the hardness change of the elastic body 90. The P valve 20 has the elastic body 9
Even if the hardness of 0 changes, the depressurizing action can be started at a value close to the preset hydraulic pressure corresponding to the wheel load, and stable control characteristics can be obtained.

The change in the hardness of the elastic body 90 does not affect the transmission of the load from the suspension spring 72 to the cylindrical member 66 and the transmission of the load from the cylindrical member 66 to the small diameter piston 78. Since the elastic body 90 is arranged between the bottom wall of the large-diameter piston 12 and the bottom wall of the cylindrical member 66 without a gap,
The change in hardness does not affect the pressure transmission.

Further, the stopper 82 for restricting the movement of the small diameter piston 78
However, when the load of the suspension spring 72 is the first set load between the valve piston 36 and the lever 62, if the gap of β ₁ is generated, the load of the suspension spring 72 becomes the first load. When the load is larger than the one set load, the valve piston 36 comes into contact with the small diameter piston 78 and pushes the small piston 78 into the elastic body 90. Therefore, the pushing amount can be smaller than when the gap is not provided, but the load of the suspension spring 72 is small. Is larger, the pushing amount is larger, and compared to the present embodiment, the hardness change of the elastic body 90 is greatly affected.

Further, in this embodiment, since the spring 52 is provided in parallel with the P valve 20, it is easy to dispose the spring 52, and the effect of improving the degree of freedom in designing the spring 52 and peripheral members is obtained. Moreover, the set load of the spring 52 can be reduced. This is apparent by comparing the case where the spring 52 is provided concentrically with the P valve 20 as in the conventional case and the case where the spring 52 is provided in parallel as in the present embodiment. In each case, the set loads F _s1 and F _s2 of the spring 52 are calculated by the following equation (4),
It is represented by (5).

However, Fp: load transmitted to the lever 62 by the small diameter piston 78 (load transmitted to the valve piston 36 when the spring 52 is concentric with the P valve 20) f: input load to the valve piston 36 ₂ < _{1 Therefore} , F _s2 <F _s1 and P valve 2
It is understood that the set load of the spring 52 can be reduced if 0 and the spring 52 are provided in parallel as in this embodiment.

Since the set load of the spring 52 can be reduced in this way, the spring 52 can be downsized,
As a result, it becomes easier to assemble and the weight is reduced.

Further, since the set load of the spring 52 can be adjusted by adjusting the bolt 56, the set load of the spring 52 is accurately set so that a minute gap β ₂ is generated between the small diameter piston 80 and the stopper 82. can do. It is not easy to provide the spring 52 with the gap β ₂ without adjustment, and the desired set load can be obtained by adjusting the bolt 56.

Further, the spring 52 is provided in parallel with the P valve 20, and the bolt 56 for adjusting the set load of the spring 52 is projected into the space opening above the large-diameter piston 12, so the spring is a P valve. Provided inside,
The adjusting operation can be easily performed as compared with the case where the set load is adjusted by adjusting the adjusting nut or the like.

Further, by adjusting the set load of the spring 52, there is an advantage that the hydraulic pressure control device can be commonly used for vehicles having different weights. If the vehicle weight is different, the depressurization start hydraulic pressure of the P valve 20 also changes. However, the set load of the spring 52 may be adjusted so that the depressurization start hydraulic pressure corresponding to the wheel load is obtained.

Another embodiment of the present invention is shown in FIG. In this embodiment, a spring 94 that applies a load to the lever 62 in a direction opposite to the load applied by the small diameter piston 78 is provided concentrically with the small diameter piston 78, and a P valve 96 is provided in parallel with the spring 94. The other structure is the same as that of the above-mentioned embodiment, the corresponding parts are designated by the same reference numerals, and detailed description thereof will be omitted.

By doing so, the amount of pushing of the small-diameter piston 78 by the valve piston 36 can be reduced compared to the case where the P-valve is provided concentrically with the small-diameter piston. When installing the P valve concentrically with the small diameter piston,
The pushing amount of the small diameter piston is approximately β ₂ . On the other hand, in this embodiment, the valve stroke of the valve piston 36 is α, and the contact portion of the lever 62 with the valve piston 36 is moved by β ₂ when the pressure is reduced. the amount is β ₂ · ₂ /
₁ and ₂ < ₁ , so that it is smaller than β _{2 and} the influence of the hardness change of the elastic body 90 can be further reduced.

Further, also in this embodiment, the set load can be reduced as compared with the case where the spring is provided concentrically with the P valve. In the case of concentricity, the spring set load F _s1 is
It is expressed by equation (4). On the other hand, in this embodiment, the set load F _s2 ′ of the spring 92 is expressed by the following equation (6).

And _{2 <1} a _{f <f · 1/2,} F s2 '<F
It turns out that it is _s1 .

Although the P-valves 20, 96 and the springs 52, 94 are provided in parallel in each of the above-described embodiments, the P-valves 20, 96 and the springs 52, 94 are not limited to being provided in parallel and may be provided at other positions than the concentric position. For example, Japanese Patent Application No. Sho 61-1963
As described in the specification of No. 13, the P-valve is arranged in the horizontal direction so that the load can be applied to the valve piston from the small diameter piston via the L-shaped bell crank lever. In this case, a spring may be engaged with the arm portion on the side where the load is transmitted from the small diameter piston of the lever to apply the load.

Further, when the springs 52 and 94 are provided in parallel, it is desirable that the set loads of the springs 52 and 94 are smaller than those provided concentrically, but this is not essential.

Further, in each of the above-described embodiments, the stopper 82 is provided to restrict the movement of the small diameter piston 78, but the stopper 82 may be omitted.

Further, in each of the above-described embodiments, a gap is provided between the small diameter piston 78 and the valve piston 36, and when the load of the suspension spring 72 is equal to or less than the first set load, the P valves 20, 94 influence the load. The present invention can be applied to a brake fluid pressure control device in which fluid pressure control corresponding to the load is performed from the beginning without providing a gap. In this case, the spring 52 serves to reduce the load transmitted from the small diameter piston 78 to the valve piston 36.

In addition, the same effect can be obtained when a limit valve is used as the pressure reducing valve, and the load sensing type brake hydraulic pressure control device in which the pressure reducing valve is attached to the unsprung member and the suspension spring are leaf springs. The present invention can be applied to a device including

In addition, although not exemplified, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an essential part of a load sensing type brake hydraulic pressure control device according to an embodiment of the present invention. FIG. 2 is a front sectional view showing a main part of a hydraulic control device according to another embodiment of the present invention. FIG. 3 is a front sectional view showing a main part of a conventional load sensing type brake hydraulic pressure control device. 10: Frame, 12: Large-diameter piston 20: Proportioning valve 22: Valve body, 36: Valve piston 52: Compression coil spring 56: Adjust bolt, 62: Lever 66: Cylindrical member 72: Suspension spring 78: Small-diameter piston, 90: Elastic body 94: Compression coil spring 96: Proportioning valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Fujii 1 Toyota-cho, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Tadashi Chiba 1-cho, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. ( 72) Inventor Atsushi Komatsu 1st Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (56) References JP-A-52-22674 (JP, A) JP-A-61-115760 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A valve piston, which projects from a valve body to the outside, is attached to either one of an unsprung member and an unsprung member connected to each other by a suspension spring of a vehicle. A pressure reducing valve for reducing the brake fluid pressure supplied to the wheel cylinder of the corresponding wheel, an input member provided between the pressure reducing valve and the suspension spring, and receiving a load of the suspension spring, and the sprung member. The unsprung member is attached to the member on the side where the pressure reducing valve is provided, transmits a part of the load received by the input member to the member, and transfers the rest to the valve piston to start the pressure reducing liquid of the pressure reducing valve. A uniaxial force divider that transmits pressure in the direction of increasing pressure and a member on the side where the pressure reducing valve is attached. A lever that is rotatably supported around and that transmits force between the force dividing device and the valve piston, and a line of action on the lever that is different from the line of action of force from the lever to the valve piston. A load-sensing brake fluid pressure control device comprising: an elastic member that exerts a force in a direction in which a force acting on the valve piston from the lever decreases.