JPH10250559A - Brake control device - Google Patents

Abstract

(57) [Problem] To provide a brake control device capable of reducing the size of a proportional control valve by eliminating a lip seal or a seal member of the proportional control valve. SOLUTION: Between each outer peripheral surface of annular projections 46 and 47 of a break point control piston portion 44 of a valve body 41 and an inner peripheral surface of a hollow portion 39 of a housing 38, and an outer peripheral surface of a base 48 and a hole of a plug 43. 49 and the inner peripheral surface, respectively, minute gaps α and β
And a metal seal is formed by each of the minute gaps α and β. The valve portion 45 of the valve body 41
An annular projection 51 is formed on the housing 3.
An annular valve seat 52 is formed in the step portion 38a of FIG. The annular valve seat 52 forms a valve seal in cooperation with the annular projection 51 of the valve body 41. This valve seal is formed by a metal seal having a minute gap γ between the outer peripheral surface of the annular projection 51 and the inner peripheral surface of the annular valve seat 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control device for adjusting a brake fluid pressure using a proportional control valve.

[0002]

2. Description of the Related Art Conventionally, a brake hydraulic circuit provided with various devices such as a master cylinder, a solenoid valve, a wheel cylinder, a pump, a reservoir, etc., in order to transmit a driver's brake operation to wheels to perform suitable braking. Is used. Some of the brake hydraulic circuits have a proportional control valve arranged in a pipe on a wheel cylinder side of a rear wheel among pipes from a master cylinder to a wheel cylinder.

[0003] The proportional control valve reduces the brake fluid pressure applied to the rear wheels from the brake fluid pressure applied to the front wheels.
It is a so-called front wheel leading lock device. In other words, if the locking of the wheels occurs first from the rear wheel side, the vehicle behavior during braking becomes unstable, so to prevent this, the front wheels tend to lock before the rear wheels so that the rear wheels tend to lock. In order to lower the brake fluid pressure on the front wheel side from the brake fluid pressure on the front wheel side.

Further, recently, by devising a method of connecting the above-described proportional control valve in the brake hydraulic circuit and using the pump together with a pump, the braking force is increased by increasing the wheel cylinder pressure instead of decreasing the wheel cylinder pressure. Research on enhancing technology is being conducted.

[0005]

In recent years, downsizing of the apparatus has been desired from the viewpoint of resource saving and low energy consumption. However, in the above-described conventional proportional control valve, downsizing is structurally required. There are difficulties and further improvement is required.

As shown in FIG. 10, a conventional proportional control valve P1
Has a piston (valve element) P3 fitted in a cylinder P2 as a housing so as to be movable in the vertical direction in the figure. The lower edge P6 of the large diameter portion P5 of the valve element P3 is seated on an annular seal member (lip seal P7) by the balance between the hydraulic pressure applied to the valve element P3 and the urging force of the spring P4. To maintain the pressure difference between the master cylinder side and the wheel cylinder side. Further, the outer periphery of the small diameter portion P8 of the valve element P3 is sealed by a seal member P9 so as to maintain the hydraulic pressure.

However, the sealing member P9 is provided with a valve body P
In order to ensure oil-tightness of the outer periphery of the small-diameter portion P8 of No. 3, a predetermined interference or more is required, so that the sliding resistance is large,
This hindered smooth movement of the valve element P3. As a countermeasure, even when the interference of the seal member P9 is reduced, the seal member P9 has a certain sliding resistance, so that the sliding resistance hinders the smooth movement of the valve element P3, so-called breakage. The point (point at which the pressure amplification factor changes) becomes unclear, and the proportional control valve P1 may not operate correctly. That is, there has been a problem that the proportional control valve P1 cannot be downsized from these.

Further, in such a proportional control valve P1, the lip seal P7 and the seal member P9 may be eroded by high pressure and pressure difference, and their durability and contamination (the lip seal P7 and the seal member P9 may be eroded). The brake fluid is contaminated by abrasion powder of rubber or erosion debris due to wear or abrasion).

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a brake control device capable of reducing the size of the proportional control valve by eliminating the lip seal and the seal member of the proportional control valve. .

[0010]

According to the first aspect of the present invention, the first brake fluid pressure is generated by the brake fluid pressure generating means in accordance with the depression force when the occupant depresses the brake pedal.
The wheel braking force generating means generates a wheel braking force by receiving the first brake fluid pressure. The pressure increasing means applies a second brake fluid pressure higher than the first brake fluid pressure to the wheel braking force generating means, and holds a differential pressure between the two brake fluid pressures by a proportional control valve.

FIG. 1 shows the operation of the proportional control valve. The horizontal axis indicates the first brake fluid pressure (for example, master cylinder pressure; M / C pressure) of the first brake fluid pressure generating means.
When the second brake fluid pressure (for example, wheel cylinder pressure; W / C pressure) of the wheel braking force generating means is taken on the vertical axis,
The relationship between the M / C pressure and the W / C pressure is determined by a predetermined break point pressure (P
0). In other words, as shown by the solid line in FIG. 1, the M / C pressure is equal to the W / C pressure up to the break point pressure, but when the break point pressure is exceeded, the W / C pressure becomes larger at a predetermined ratio (ie, at a predetermined ratio) kM / C pressure = W / C pressure).

In particular, in the present invention, instead of the conventional structure of sealing with a lip seal, a hydraulic pressure receiving portion for forming a proportional pressure generated by an area difference perpendicular to the axial direction of the valve body is provided between the housing and the valve body. The proportional control valve can be reduced in size because it is constituted by the gap between them.

That is, conventionally, downsizing of the lip seal could not be performed due to instability of the break point caused by sliding resistance, and thus the proportional control valve could not be downsized. By adopting a unique configuration of the gap forming the hydraulic pressure receiving portion, the lip seal can be eliminated, so that the proportional control valve can be downsized.

According to the second aspect of the present invention, the air chamber of the proportional control valve communicates with the master reservoir, and the brake fluid is introduced into the air chamber. In other words, the valve element slides in the space completely filled with the brake fluid, so that the movement of the valve element is smaller than in the conventional case where air is introduced into the air chamber. Become smooth.

According to the third aspect of the present invention, the orifice for restricting the flow of the brake fluid is disposed in the pipeline between the air chamber into which the brake fluid is introduced and the master reservoir. Therefore, the flow of the brake fluid is rectified, and the movement of the valve body is further smoothed as compared with the case of the second aspect of the invention.

According to the fourth aspect of the present invention, the liquid pressure receiving portion is formed by a gap between the valve body-side protrusion protruding annularly around the valve body and the housing-side protrusion protruding annularly toward the hollow portion of the housing. Is configured. In other words, when the valve element moves, the gap between the valve element-side projection and the housing-side projection becomes very narrow, thereby creating a state substantially similar to that of sealing. , And the pressure difference between the brake fluid pressure on the wheel cylinder side (for example, increased by a pump).

According to the fifth aspect of the present invention, the valve body is a ball, and the gap between the ball and the housing in which the ball is housed constitutes the hydraulic pressure receiving portion. Thus, the movement of the ball and the very narrow gap between the ball and the housing creates a substantially seal-like condition, whereby, for example, the brake fluid pressure on the master syringe side (for example the pump Increased by
Holds the pressure difference from the brake fluid pressure on the wheel cylinder side.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a brake control device according to the present invention will be described below in detail with reference to the drawings by way of examples (embodiments). (Example 1) a) First, a schematic configuration of a brake control device of the present example will be described.
A description will be given based on FIG. The brake control device according to the present embodiment includes a brake booster and a pressure amplifying mechanism including a pump and a proportional control valve in order to perform brake assist. A description will be given using a brake control device as an example.

As shown in FIG. 2, the brake control device according to the present embodiment includes a vacuum booster 1 as a brake booster, and a brake pedal 2 is connected to the input side of the vacuum booster 1. A tandem type master cylinder 3 is connected to the output side. Further, the master cylinder 3 is connected to a master reservoir 4 and a hydraulic control circuit 6 composed of two hydraulic systems of first and second piping systems A and B of X piping (diagonal piping).

The vacuum booster 1 is provided with a negative pressure chamber (constant pressure chamber) 11 and a variable pressure chamber 12 partitioned by a diaphragm 7. This vacuum booster 1
The booster exerts a boosting action in response to the depression of the brake pedal 2. The negative pressure of the intake manifold (intake negative pressure) generated by an engine (not shown) is supplied to the constant pressure chamber 11.
At the same time, the atmospheric pressure is introduced into the transformation chamber 12, and the force applied to the piston (not shown) of the master cylinder 3 is increased by utilizing the pressure difference between the two chambers 11, 12.

In the hydraulic control circuit 6, the master cylinder 3 and the wheel cylinder 14 of a certain wheel 13 are communicated via the first piping system A. Here, the first piping system A will be described. The hydraulic control circuit for the second piping system B is not shown.

The first piping system A has a master cylinder 3
A proportional control valve 22 is disposed in a pipe 21 extending from the wheel cylinder 14 to the wheel cylinder 14, and a pump 24 is disposed in a pipe 23 provided in parallel with the proportional control valve 22. The proportional control valve 22 uses a conventional proportional control valve for reducing the brake oil pressure on the rear wheel side in reverse connection and uses a pump 24.
And a (reversely connected) proportional control valve 22 constitute a pressure amplifying mechanism. The reverse connection of the proportional control valve 22 means that the high pressure side (the second communication hole 27 side) of the proportional control valve 22 is the wheel cylinder 21 side, and the low pressure side (the first communication hole 26 side) is the master cylinder 3 side. The connection method.

The conduit 21 communicates with a first communication hole 26 of the proportional control valve 22, and the conduit 23 communicates with the second communication hole 26 of the proportional control valve 22.
It communicates with the communication hole 27. A pipe 28 branched from the pipe 21 communicates with a third communication hole 29 of the proportional control valve 22. The pipe 28 is an electromagnetic valve that controls opening and closing of the pipe 28. One control valve 31 is arranged.
The first control valve 31 shuts off the pipe line 28 when it is off,
When it is on, the pipe 28 is opened to supply the master cylinder pressure to the third communication hole 29 side.

Further, a second control valve 34, which is an electromagnetic valve for opening and closing the pipe 33, is disposed in a pipe 33 communicating from the master reservoir 4 to the fourth communication hole 32 of the proportional control valve 22. I have. The second control valve 34 opens the pipeline 33 to open the fourth communication hole to the atmospheric pressure when it is off, and shuts off the pipeline 33 when it is on. In addition, pipeline 3
A pipe 36 branched from 3 communicates with a fifth communication hole 37 (conventionally called an air chamber) of the proportional control valve 22.

The proportional control valve 22 has a housing 3
A stepped hollow portion 39 (having a larger diameter toward the lower side in FIG. 2)
In the hollow portion 39, there is provided a valve body 41 slidable in the vertical direction in FIG. 2 and a set spring 42 for urging the valve body 41 upward (in the direction of arrow C) in FIG. At the same time, the lower end of the set spring 42 is
It has a plug 43 fixed inside.

A valve portion 45 having a large diameter is provided substantially at the center of the valve body 41, and at the input end (upper part in FIG. 2),
As shown in the figure, the break point control piston 44 having a pressure receiving area S3 smaller than the pressure receiving area S1 on the input side of the valve body 41
It protrudes from 5. In addition, the break point control piston unit 4
A pair of annular projections 46 and 47 are formed on the outer periphery of the pair 4 so as to be spaced apart in the axial direction.

In the valve element 41, the break point control piston 44 is slidably disposed in a small diameter portion (upper part in FIG. 2) of the hollow part 39 of the housing 38, as shown in FIG. As shown in (b), a base 48 of the valve element 41 is slidably disposed in a hole 49 of the plug 43 closing the hollow portion 39. And the valve element 41 of the hole 49 of the plug 43
The lower part of the base 48 is an air chamber.

At this time, the outer peripheral surfaces of the annular projections 46 and 47 of the break point control piston 44 and the hollow portion 3 of the housing 38
9 is set to a minute gap α of 10 μm or less, and the outer peripheral surface of the base 48 and the hole 4 of the plug 43 are set.
A small gap β of 10 μm or less is also set between the inner gap 9 and the inner peripheral surface, and a metal seal is formed by each of the small gaps α and β. That is, the minute gaps α and β are in a state in which the brake oil is sealed by these metal seals.

Further, the valve portion 45 of the valve body 41
As shown in (c), an annular projection 51 having a pressure receiving area S1 is formed, and an annular valve seat 52 protruding toward the center of the shaft is formed on the step portion 38a of the housing 38. The annular valve seat 52 forms a valve seal in cooperation with the annular projection 51 of the valve body 41. The valve seal comprises an outer peripheral surface of an annular projection 51 and an annular valve seat 52.
Is formed by a metal seal having a minute gap γ of 10 μm or less between itself and the inner peripheral surface. That is, the minute gap γ seals the brake oil by the metal seal. The minute gaps α, β, γ are 10 μm
Although not limited to the following, it is desirable to set the thickness to 10 μm or less in order to reduce the influence of oil leakage from the metal seal and substantially operate the brake.

The cross-sectional area of the pair of annular projections 46 and 47 of the break point control piston 44 is both set to S3, and the cross-sectional area of the base 48, which is a portion not receiving pressure, is set to a value S2 larger than S3. Is set, and the annular projection 5
The cross-sectional area S1 of 1 is set to a value larger than the cross-sectional area S2 of the base, and thus has a relationship of S3 <S2 <S1.

Then, as shown in FIG.
In the non-operating state, the master cylinder 3 is connected to the wheel cylinder 14 via the conduit 21, the first communication hole 26, the gap between the valve portion 45 of the valve element 41 and the housing 38, and the second communication hole 27. Have been. The upper surface of the break point control piston portion 44 of the valve body 41 is connected to the master reservoir 4 through the fourth communication hole 32, the second control valve 34, and the pipe line 33, and is open to the atmospheric pressure. . Further, the hole 49 of the plug 43, which is an air chamber below the base 48 of the valve element 41, is provided with the orifice 53, the fifth communication hole 37, the pipe 36, and the pipe 33.
, Is similarly connected to the master reservoir 4 and is open to atmospheric pressure.

B) As shown in FIG. 4, the ECU 61 for controlling the above-mentioned brake control device is provided with a well-known CPU
1a, a ROM 61b, a RAM 61c, an input / output unit 61d, a bus line 61e, and the like. The ECU 61 includes a wheel speed sensor 62 disposed on each wheel to detect a wheel speed, a brake switch 63 for detecting depression of the brake pedal 2, and a constant pressure chamber (negative pressure chamber) 11 in the vacuum booster 1.
Constant pressure chamber pressure sensor 64 for detecting the pressure inside
Signals from a variable pressure chamber pressure sensor 66 for detecting internal pressure, an M / C pressure sensor 67 for detecting a master cylinder pressure, and a W / C pressure sensor 68 for detecting a wheel cylinder pressure are input.

From the ECU 61, a pressure-increasing control valve 71, a pressure-reducing control valve 72, a pump motor 73 for driving the pump 24, an electromagnetic valve, a first control valve 31, and a second
A control signal for driving a control actuator such as the control valve 34 is output. c) Next, the control processing of this embodiment will be described based on the flowchart of FIG.

Here, an example will be described in which even if the vacuum booster 1 is normal, pressure amplification by a pressure amplification mechanism is performed in order to further increase the braking force.
First, in step 100 in FIG. 5, it is determined whether or not the brake pedal 2 is depressed, based on whether or not the brake switch 63 is on. If the determination is affirmative, the process proceeds to step 110, while if the determination is negative, the same determination is repeated again.

In step 110, pressure amplification is performed by a pressure amplifying mechanism in order to increase the boosting action of the vacuum booster 1 and increase the wheel cylinder pressure. Specifically, when the master cylinder pressure is generated by depressing the brake pedal 2, the master cylinder pressure acts on the valve element 41,
When the urging force of the set spring 42 is overcome, the valve element 41
Moves downward, the annular projection 51 of the valve portion 45 and the housing 3
A valve seal is formed by the eight annular valve seats 52, and the communication between the master cylinder 3 and the wheel cylinder 14 is substantially cut off.

At this time, since the master cylinder pressure rises above a predetermined value, when the master cylinder pressure is detected, the pump motor 73 is energized and the pump 24 is driven. This allows
The brake oil on the master cylinder 3 side is the wheel cylinder 1
Since it is sent to the fourth side, the wheel cylinder pressure is increased, and this process is once ended.

The operation of the first control valve 31 and the second control valve will not be described in detail here. For example, when the vacuum booster 7 fails, the first control valve 31 is opened and the second control valve 31 is opened. By shutting off the control valve 34, the break point pressure is reduced and the pressure increase start timing is advanced, so that the function of the failed vacuum booster 7 can be supplemented.

D) Next, the operation of the valve body when the above-mentioned control is performed and the operation and effect thereof will be described with reference to FIGS. 1 and 6. As shown in FIG. 1, the break point pressure of the proportional control valve 22 is the value of P0 set by the urging force of the set spring 42. Therefore, when the vacuum booster 1 is normal, the master cylinder pressure (M / C pressure) and the wheel cylinder pressure (W / C pressure) as shown by the solid line in FIG.
And the relationship is set.

Then, as shown in FIG.
Is inactive (at rest), the valve element 41 moves upward in the figure by the urging force of the set spring 42, and the valve portion 44
Is stationary at a position where the upper end of the is in contact with the step 38a of the housing 38. Next, as shown in FIG. 6B, when the brake pedal 2 is depressed and the master cylinder pressure increases accordingly, the valve body 41 moves downward in the figure by the pressing force, and the annular projection is formed. 51 and the annular valve seat 52 come close to each other, so that a valve seat is formed.

When it is detected that the master cylinder pressure is close to the pressure at which the movement of the valve element 41 starts (ie, the break point pressure), the M / C pressure sensor 64 and the constant pressure chamber pressure sensor 64 , The operation of the pump motor 73, that is, the pump 24 is started.

As a result, as shown in FIG. 1, when the breaking point pressure is equal to or higher than P0, the degree of increase of the wheel cylinder pressure with respect to the master cylinder pressure becomes large, so that a large braking force is exerted even with a small pedaling force. It is possible to do. As shown in FIG. 6C, for example, the first control valve 31
Is opened, and the urging force for pressing the valve body 41 downward in the drawing increases, the valve body 41 moves below the position where the valve seal is made.

As described above, in the present embodiment, the valve seal is not performed by shutting off the flow path between the master cylinder 3 and the wheel cylinder 14 by using the conventional lip seal. An annular projection 51 is provided on the valve portion 44, and an annular valve seat 52 is provided on the step portion 38a of the housing 38, and a flow path is substantially formed by a gap γ formed between the annular projection 51 and the annular valve seat 52. Shut off and perform valve seal. Further, a metal seal is used to maintain oil tightness between the outer peripheral surface of the base portion 48 of the valve body 41 and the inner peripheral surface of the hole 49 of the plug 43.

Therefore, there is no problem when the seal member is used, that is, the problem that the breaking point pressure fluctuates due to the sliding resistance and the operation becomes unstable. In addition, there is no problem of durability and contamination of the seal that occurs when a lip seal or a seal member is used.

Therefore, in this embodiment, the entire proportional control valve 22 including the valve element and its surroundings can be reduced in size, which can contribute to resource saving and energy saving. In this embodiment, the conventional air chamber (open to the atmosphere) is abolished, the fifth communication hole 37 communicates with the master reservoir 4, and brake oil is introduced into the hole 49 of the plug 43. Therefore, there is an advantage that the movement of the valve body 41 becomes smooth.

Further, the hole 49 of the plug 43 and the fifth communication hole 3
6 is provided with an orifice 53 for narrowing the flow path of the brake oil, so that the movement of the valve body 41 becomes smoother. (Embodiment 2) Next, Embodiment 2 will be described, but the description of the same parts as in Embodiment 1 will be omitted or simplified.
In this embodiment, since only a part of the configuration in the first embodiment is changed, the same reference numerals are used in the drawings.

As shown in FIG. 7, in the brake control device according to the present embodiment, the base 48 of the valve element 41 of the proportional control valve 22 is slidably fitted in the hole 49 of the plug 43.
The lower side of the base 48 of the third hole 49 is a sealed air chamber 77.
It has become. That is, in the present embodiment, the conduit 36 from the master reservoir 4 to the air chamber 77 is not provided,
Therefore, no brake oil is introduced into the air chamber 77. Further, the orifice 53 is not provided.

As described above, in the present embodiment, the pipe 36 extending from the master reservoir 4 to the air chamber 77 can be omitted, and since there is no need to provide the orifice 53, the structure can be simplified and the proportional control valve 22 can be used. There is an advantage that the size can be further reduced. (Embodiment 3) Next, Embodiment 3 will be described, but the description of the same parts as in Embodiment 1 will be omitted or simplified.

A) As shown in FIG. 8, the brake control device of this embodiment includes a vacuum booster 81 as a brake booster, and a brake pedal 82 is connected to the input side of the vacuum booster 81. A tandem type master cylinder 83 is connected to the output side. The master cylinder 83 has a master reservoir 84,
A hydraulic control circuit 86 composed of two hydraulic systems of first and second piping systems A and B of the X piping is connected.

In the hydraulic control circuit 86, a master cylinder 83 and a wheel cylinder 94 of a certain wheel 93 are communicated via a first piping system A. Here, the first piping system A will be described. In the first piping system A,
A proportional control valve 102 is disposed in reverse contact with a pipe 101 extending from the master cylinder 83 to the wheel cylinder 94, and a pump 104 is disposed in a pipe 103 provided in parallel with the proportional control valve 102.

The conduit 101 communicates with a first communication hole 106 of the proportional control valve 102, and the conduit 103 communicates with the proportional control valve 1
02 communicates with the second communication hole 107. Further, the master reservoir 84 and the third communication hole 108 are communicated with each other by a pipe 109. In the proportional control valve 102, a sleeve 113 having a flow path from the first communication path 106 to the second communication path 107 is fixedly disposed in a hollow portion 112 of a housing 111 thereof.

A rod 114 slidable in the vertical direction in the figure, a ball 116 fixed to the upper end of the rod 114, and a support plate 117 for supporting the lower end of the rod 114 are arranged in the sleeve 113. 117 is urged upward by a set spring 118 in the figure. still,
The ball 116 is press-fitted and fixed to the rod 114, and the ball 116 and the rod 114 move integrally.

The communication hole 115 provided inside the sleeve 113 is set in accordance with the size of the ball 116. That is, as shown in FIG. 9, the inner diameter of the large-diameter portion 115a above the communication hole 115 is considerably larger than the outer diameter of the ball 116 (for example, a gap of 0.7 mm) so that a sufficient flow path for brake oil can be secured. Degree) is set. The inner diameter of the middle diameter portion 115b below the large diameter portion 115a is
The gap is set to be small (10 μm or less) so that a metal seal that substantially blocks the flow path is possible.
Further, a portion from the middle diameter portion 115b to the small diameter portion 115c is tapered, and is configured as a valve seat 115d on which the ball 116 sits.

In this embodiment, the metal seal is performed between the outer diameter of the ball 116 and the inner diameter of the middle diameter portion 115b. However, a gap is provided between the outer diameter of the ball 116 and the inner diameter of the middle diameter portion 115b (for example, The flow path in the sleeve 113 may be blocked by the ball 116 sitting on the valve seat 115d (the gap is about 0.2 mm).

Returning to FIG. 8, in the hole 121 in which the set spring 118 is disposed (corresponding to a conventional air chamber), brake oil is supplied from the master reservoir 84 through the pipe line 109 and the third communication hole 108. Introduced holes 121
The orifice 12 has a flow path between the
2 are provided.

The proportional control valve 102 has a bypass passage 123 extending from the first communication passage 106 to the second communication passage 107 so as to bypass the flow passage in the sleeve 113 in order to secure the flow rate of the brake oil. Is provided. The bypass passage 123 is provided with a valve mechanism including a ball 124 and a spring 125 so as to open the passage when a predetermined pressure is reached.

B) Next, the operation of this embodiment will be described with reference to FIG. First, when the brake pedal 82 is not depressed, as shown in FIG. 9A, the rod 114 and the ball 116 are moved upward in the figure by the urging force of the set spring 118. The flow path, that is, from the master cylinder 83 to the wheel cylinder 94
The channel leading to is open.

Next, when the brake pedal 82 is depressed,
Brake oil from master cylinder 83 is supplied to first communication passage 1
06, through the gap between the ball 116 and the large-diameter portion 115a of the communication hole 115, the communication hole 115, and the second communication passage 107, and supplied to the wheel cylinder 94. At this time, the ball 11
6, and the gap between the large-diameter portion 115a of the communication hole 115 is small,
When the flow of the brake oil is restricted, particularly in the case of sudden depression, the brake oil is supplied to the wheel cylinder 94 through a valve mechanism including a ball 124 and a spring 125 provided in the bypass passage 123, Secure brake oil flow.

The master cylinder pressure acts so that the rod 114 acts downward. When the acting force overcomes the urging force of the set spring 118, the rod 114 moves downward as shown in FIG. Then, the valve is sealed by the ball 116 and the middle diameter portion 115b, and the communication hole 115 in the sleeve 113 is shut off. When the master cylinder pressure reaches a predetermined pressure near the pressure at which the communication hole 115 is shut off, the pump 104 is driven, and the wheel cylinder pressure increases.

As a result, the ball 116 is urged upward in the figure, and the sum of the force for moving the ball 116 upward due to the wheel cylinder pressure and the urging force of the set spring 118 and the ball 116 downward due to the master cylinder pressure are applied. The force that tries to move is balanced and works to maintain the pressure difference between the master cylinder pressure and the wheel cylinder pressure.

As described above, the same operation and effect as in the first embodiment can be obtained by the structure of the sleeve 113 having the step in the internal communication hole 115 and the rod 114 and the ball 116 arranged in the communication hole 115. It is needless to say that the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the technical scope of the present invention.

(1) For example, in the first and second embodiments, the brake booster using the engine negative pressure and the atmospheric pressure has been described as an example.
For example, a hydraulic pressure booster, a compressed air pressure brake booster, or the like utilizing a hydraulic pressure or a compressed air pressure using a pressure source can be employed.

(2) The structure of the proportional control valve is not limited to the above-described embodiment, and various structures can be employed. (3) Further, front and rear pipes can be adopted instead of the X pipes.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a master cylinder pressure and a wheel cylinder pressure.

FIG. 2 is a schematic configuration diagram illustrating a brake control device according to the first embodiment.

FIG. 3 is an explanatory diagram showing an enlarged main part of the brake control device according to the first embodiment;

FIG. 4 is a block diagram illustrating an electrical configuration of the first embodiment.

FIG. 5 is a flowchart illustrating a control process according to the first embodiment.

FIG. 6 is an explanatory diagram showing the movement of the valve body according to the first embodiment.

FIG. 7 is a schematic configuration diagram illustrating a brake control device according to a second embodiment.

FIG. 8 is a schematic configuration diagram illustrating a brake control device according to a third embodiment.

FIG. 9 is an explanatory diagram illustrating an operation of the brake control device according to the third embodiment.

FIG. 10 is an explanatory diagram showing a conventional technique.

[Explanation of symbols]

 1, 81 vacuum booster 2, 82 brake pedal 3, 83 master cylinder 6, 86 hydraulic control circuit 11, constant pressure chamber (negative pressure chamber) 14, 94 wheel cylinder 24, 104 pump 22, 22, proportional Control valve 41 ... Valve 42,118 ... Set spring 26,106 ... First communication hole 27,107 ... Second communication hole 29,108 ... Third communication hole 32 ... Fourth communication hole 37 ... Fifth communication hole 77 ... Air chamber 116… Ball 114… Rod

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takahiro Goshima 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Co., Ltd. Inside the Matsuyama Factory of Equipment Co., Ltd. (72) Yoshio Tobizawa, Inventor 2--11-6, Shinmeicho, Higashimatsuyama City, Saitama Prefecture Inside of the Matsuyama Factory of Automotive Equipment Co., Ltd. No. 6 Inside the Matsuyama Plant of Automotive Equipment Co., Ltd.

Claims (5)

[Claims] 1. A brake fluid pressure generating means for generating a first brake fluid pressure in accordance with a depressing force of an occupant when depressing a brake pedal, and a wheel braking force in response to the first brake fluid pressure. Wheel braking force generating means, pressure increasing means for applying a second brake pressure higher than the first brake fluid pressure to the wheel braking force generating means to perform brake assist, and the pressure increasing means formed by the pressure increasing means A proportional control valve for maintaining a differential pressure between the first brake fluid pressure and the second brake fluid pressure, wherein the proportional control valve is fitted into a hollow portion in a housing of the proportional control valve. The housing is provided with a valve body that is inserted and movable in its own axial direction in the hollow portion, and a hydraulic pressure receiving portion for forming a proportional pressure generated by an area difference perpendicular to the axial direction of the valve body is provided in the housing. Between the valve body A brake control device, comprising: 2. The brake control device according to claim 1, wherein an air chamber of the proportional control valve communicates with a master reservoir, and brake fluid is introduced into the air chamber. 3. The orifice according to claim 1, wherein an orifice for restricting a flow of the brake fluid is disposed in a pipeline between the air chamber into which the brake fluid is introduced and a master reservoir. The brake control device according to the above. 4. The liquid pressure receiving portion is constituted by a gap between a valve body-side protrusion protruding annularly around the valve body and a housing-side protrusion protruding annularly toward the hollow portion of the housing. 4. The method according to claim 1, wherein:
The brake control device according to any one of the above. 5. The liquid pressure receiving portion according to claim 1, wherein the valve body is a ball, and a gap between the ball and the housing in which the ball is accommodated constitutes the hydraulic pressure receiving portion. The brake control device according to any one of claims 1 to 3.