JPH0577712A - Liquid pressure assistor of brake for vehicle - Google Patents

Abstract

PURPOSE:To shorten an overall length, increase output accuracy, and make an input stroke smaller than an output stroke, in the case of a liquid pressure assistor of brake for vehicle for assisting stepping power on a brake pedal by liquid pressure piston drive and transmitting the stepping power to a master cylinder. CONSTITUTION:A device is provided between a master cylinder and a brake pedal, and by which a stepping power on the pedal is assisted and transmitted to the master cylinder. An output lever 2 connected to an output member 3 and an input lever 4 connected to an input member 5 are provided in the device. The input lever 4 is rockably supported on a case 1, and the output lever 2 and the input lever 3 are rockably connected to each other, and also the output lever 2 and an assist piston 6 are connected to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic brake booster for a vehicle brake, which boosts the pedal effort of a brake pedal by hydraulically driving a piston to transmit the boosted force to a master cylinder.

[0002]

2. Description of the Related Art Conventionally, as a hydraulic booster for a vehicle brake, for example, those disclosed in JP-A-60-52015 or JP-A-62-244750 are known. That is, in the conventional hydraulic booster, a booster piston mechanism integrally provided with a control valve is coaxially arranged between the master cylinder and the brake pedal, and the booster piston is operated by pushing the brake pedal to operate the control valve. It is hydraulically driven to boost the pedal effort and transmit it to the master cylinder.

[0003]

However, such a conventional hydraulic booster has the following problems. First, the distance between the mounting surface of the hydraulic booster on the vehicle body and the mounting surface of the master cylinder is long, and the total length including the master cylinder is long.

Secondly, in the boost control, the frictional resistance of the hydraulic seals has a great influence, the output hysteresis is large, and it is difficult to accurately control the boost of the output with respect to the input.
Third, it is difficult to make the input stroke smaller than the output stroke. The present invention has been made in view of such conventional problems, and provides a hydraulic booster for a vehicle brake, which can shorten the overall length, has high output accuracy, and can have an input stroke smaller than that of the output stalk. The purpose is to do.

[0005]

To achieve this object, the present invention is constructed as follows. The reference numerals in the drawings of the embodiments are also shown. First, the present invention is directed to a vehicle brake hydraulic booster that is provided between a master cylinder and a brake pedal and boosts a pedaling force to transmit the boosted pedaling force to the master cylinder.

In the present invention as such a hydraulic booster for a vehicle brake, the output lever 2 connected to the output member 3 and the input lever 4 connected to the input member 5 are provided, and the input lever 4 is provided. Is swingably supported on the case 1, and the output lever 2 and the input lever 3 are swingably connected,
Further, the output lever 2 and the boosting piston 6 are connected to each other.

Here, the output member 2 is guided by the guide groove 13 provided in the case 1. Also, the amount of deviation in the swing direction between the input lever 4 and the output lever 2 is detected,
This shift amount is transmitted from the input lever 4 and the output lever 2 near the support portion of the case 1 to the control valve 7 of the booster piston 6. The hydraulic booster of the present invention is disclosed in Japanese Patent Application Nos. 3-98512 and 3-9851 already proposed by the present inventors.
The booster piston 6 of No. 3 and 3-98514 is connected to the input lever 4, whereas the booster piston 6 is connected to the output lever 2.

[0008]

The hydraulic brake booster for a vehicle according to the present invention having the above-described structure provides the following actions. First, according to the present invention, the boosting piston 6 is arranged at a position away from the center line of the master cylinder, and both are arranged in two levers 2, 4
Connect with.

That is, the case 1 of the hydraulic booster is provided with the input lever 4 supporting the fulcrum point A, and the point B at one end of the input lever 4 can be connected to the brake pedal via the input member 5. , The output lever 2 is swingably connected at an intermediate point C. The output lever 2 is connected to the output member 3 at a point C on the master cylinder side, and is connected to the boosting piston 6 at a point E outside the point C.

Further, the output lever 2 has a hydraulic pressure control valve 7 at a point F near a point A which is a case supporting point of the input lever 4.
Connect with. That is, when the hydraulic control valve 7 is in the neutral state when the input lever 4 and the output lever 2 overlap (the point F and the point A overlap), and the point F of the output lever 2 goes to the left of the point A. The boosting hydraulic pressure is increased, and when the pressure is increased to the right, the pressure is reduced.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing an embodiment of the present invention. In FIG. 1, reference numeral 1 is a case of a hydraulic booster, which has a mounting surface 8 to the vehicle body on the right side and a mounting surface 11 to a master cylinder 10 via a mounting plate 9 on the left side.

An output lever 2 and an input lever 4 are provided in the case 1. The output lever 2 has an output member 3 connected to an intermediate portion by a shaft 12, and a tip of the output member 3 presses a piston built in the master cylinder 10. Further, the output lever 2 has guide grooves 13 formed on the inner surface of the case 1 on both sides of the shaft 12 connecting the output member 3 to the output lever 2 as is apparent from FIG. 2 showing the XX cross section of FIG. The rollers 14 mounted on both ends of the shaft 12 rotate in the guide groove 13 to restrict the movement of the output member 3 accompanying the swing of the output lever 2. That is, the guide groove 13 is formed parallel to the piston axis of the master cylinder 10,
By swinging the output lever 2, the output member 3 is moved to the master cylinder 10
It is designed to move parallel to the piston center line.

Referring again to FIG. 1, one end of the input lever 4 is swingably supported by the shaft 15 with respect to the case 1. A receiving portion 16 is formed at an end portion of the shaft 15 of the input lever 4 opposite to the supporting portion, and the input member 5 is in contact with the receiving portion 16. The input member 5 advances in the axial direction in response to the depression of the brake pedal 17, and presses the receiving portion 16 of the input lever 4 toward the master cylinder 10 side.

The output lever 2 and the input lever 4 are swingably connected at a lower end portion of the output lever 2 and an intermediate portion of the input lever 4. That is, the roller 19 is attached to the lower end of the output lever 2 by the shaft 18, and the roller 19 is brought into contact with the connection guide portion 20 formed in the intermediate portion of the input lever 4 so that the input lever 4 is connected.
On the other hand, the output lever 2 side is swingably connected in a relatively movable state.

Further, a return spring 21 is attached to the connecting portion between the output lever 2 and the input lever 4.
The return spring 21 is a winding spring, which is attached to the shaft 15 and has one end abutting on the case 1 side and the other end abutting the output lever 2 so that the roller 19 of the output lever 2 is always connected to the input lever 4. It is urged so as to abut the portion 20.

A boosting piston 6 is connected to the upper end of the output lever 2. That is, the boosting piston 6 is slidably incorporated in the boosting cylinder 22 formed in the case 1, and the hydraulic chamber 24 partitioned by the cup seal 23 is formed on the right side of the boosting piston 6. The shaft 2 is attached to the upper end of the output lever 2.
The piston rod 26 is connected by 5, and the tip of the piston rod 26 abuts the boosting piston 6 so that the output lever 2 can be pressed to the master cylinder 10 side via the piston rod 26. The booster piston 6 is subjected to hydraulic pressure control by the control valve 7 shown in FIG.

FIG. 2 shows a cross section taken along the line XX of FIG. In FIG. 2, the input lever 4 is swingably supported by the shaft 15 on the lower side of the case 1, and the tip end of the input member 5 is in contact with the receiving portion 16 above the input lever 4. The output lever 2 is formed of a pair of members provided so as to sandwich the input lever 4. The lower end of the output lever 2 has a shaft 1
A roller 19 is connected by 8. Further, the output member 3 is connected to the intermediate portion of the output lever 2 by the shaft 12 as described above, and the roller 1 mounted on both ends of the shaft 12
4 is fitted in the guide groove 13 on the case 1 side. Further, a piston rod 26 is connected to the upper end of the output lever 2 by a shaft 25. Roller 19 to input lever 4
The return spring 21 that presses the input lever 4 is wound around a shaft 15 that supports the input lever 4 on the case 1.

A control valve 7 is incorporated in the center of the right side of the case 1. The control valve 7 has a structure shown in FIG. In addition to the control valve 7, FIG. 3 also shows the hydraulic circuit for the control valve 7 and the booster piston 6 side that serves as a control load. In FIG. 2, the movement of the output lever 2 is transmitted to the control valve 7. That is, the lower end portion of the right side member of the output lever 2 has the arm portion 27.
Is extended to the portion of the shaft 15 that supports the input lever 4 on the case 1, and the knob 28 is attached to the tip of the arm portion 27.
And a lower end of a valve lever 30 provided swingably on the case 1 is connected by a shaft 29. That is, the guide groove 31 is formed at the lower end of the valve lever 30, and the knob 28 provided at the tip of the arm portion 27 is inserted in the guide groove 31.

As shown in FIG. 3, the upper end of the valve lever 30 is fitted into a connecting groove formed on the outside of the spool 32 of the control valve 7 so that the output lever moves to the spool 32 via the valve lever 30. It is transmitted. The control valve 7 has a valve sleeve 34 incorporated in the case 1, and a spool 32 slidably incorporated in a shaft hole of the valve sleeve 34. A pump port P, a tank port T, and a control port C are formed on the valve sleeve 32. The spool 32 has lands 35 and 36 at two locations, and the land 35 serves to provide the pump port P at the neutral position in the drawing.
The control port C is closed, and the control port C is opened to the tank port T. The land 36 partitions the tank port T and the pump port P. When the spool 32 moves to the right, the land 35 communicates the pump port P with the control port C and supplies the control hydraulic pressure to the hydraulic pressure chamber 24 of the booster piston 6. The spool 32 is pressed by a return spring 37 provided on the right side so as to return to the neutral position shown in the figure.

A hydraulic pump 39 driven by a motor 38, an accumulator 40, and a reservoir tank 41 are provided as a hydraulic circuit for the control valve 7. FIG. 4 is an explanatory view showing an embodiment of the booster hydraulic apparatus of the present invention shown in FIGS. 1, 2 and 3 by a link mechanism. In FIG.
The output lever 2 and the input lever 4 are swingably connected at a point C. The intermediate portion of the output lever 2 is connected to the output member 3 at point D.

The input lever 4 is swingably supported by the case 1 at the lower point A, and is connected to the input member 5 at the upper point B. A boosting piston 6 provided in a boosting cylinder 22 is connected to a point E at the upper end of the output lever 2. The control valve 7 of the booster piston 6 is connected to the output lever 2 at a point F near the point A that supports the input lever 4 on the case 1.

Next, the operation of the embodiment shown in FIGS. 1 to 4 will be described. When the input member 5 is pressed to the left by depressing the brake pedal 17 from the initial state shown in the figure, the input lever 4 moves to the A position.
It swings and rotates around the point, and point C moves to the left. This movement of the point C causes the output lever 2 to swing and rotate around the point E, and the output member 3 (point D) slightly moves to the left. Therefore, the point F at the lower end of the output lever 2 also moves to the left. The movement of the output lever F point is transmitted to the spool 32 of the control valve 7 shown in FIG. 3, moves the spool 32 to the right, and moves the pump port P.
Is supplied to the hydraulic chamber 24 of the boosting cylinder 22 via the control port C. Therefore, the boosting piston 6 pushes the E point of the output lever 2 to the left side, and the output lever 2 swings and rotates around the C point to move the D point further to the left side to boost the output member 3. The piston 6 presses the master cylinder 10 side.

When the output lever 2 is moved by the boosting piston 6, the movement amount (oscillation angle) of the input lever 4 and the movement amount (oscillation angle) of the output lever 2 become substantially equal to each other.
The control valve 7 returns to the neutral state by overlapping the point and the point F, and the supply of hydraulic pressure to the boosting piston 6 is stopped, so that the movement of the boosting piston 6 also stops. Explaining the power relationship here,
The booster hydraulic pressure acting on the booster piston 6 acts on the E point of the output lever 2, and the force acting on the E point acts on the D point, that is, the output member 3 and the C point, that is, the input lever 4. The force applied to the point C is transmitted to the input member 5 as a reaction force via the input lever 4, and the equilibrium point is obtained when the reaction force to the input member 5 and the input by depressing the brake pedal coincide. The control valve 7 becomes neutral.

Here, assuming that the boost ratio = (output) / (input) is N, N = (b.d) / (a.c) where a: distance between A and C b: between A and B Distance c: Distance between D and E d: Distance between C and E

What is important here is that the relationship between input and output is determined by the forces acting on the input lever 4 and the output lever 2 described above, so in the hydraulic booster of the present invention, the input lever is used. Although there is an influence of the mechanical friction of the connecting point of the output lever 2 and the output lever 2 and the frictional resistance of the control valve 7, it is not related to the value of the frictional resistance of the hydraulic seal member (cup seal 23) of the booster piston 6.

As a result, in the conventional general hydraulic booster, the frictional resistance due to the high hydraulic pressure acting on the seal provided on the input member and the booster piston has a great influence, and the friction against the input is increased. Although there is a problem that the output control accuracy (accuracy of proportional relationship) is poor, in the present invention, the cup seal 23 as the hydraulic seal provided on the booster piston 6 is used.
Since the frictional resistance of is not a factor that determines the output value,
It is possible to control the proportional relationship between the input and output with high accuracy. Further, as shown in FIG. 4, the swing radius determined by the AD of the output lever 2 is greater than the swing radius determined by the distance between the AB of the input lever 4. By setting it longer, the input stroke can be shorter than the output stroke.

If the input stroke can be made shorter than the output stroke in this way, even if the hydraulic pressure on the booster piston 6 is lost and the boosting action is lost, the movement of the input lever 4 is mechanically changed to the output lever. 2, and the stroke of the input member 5 and the output member 3 is approximately 1: 1.
Therefore, the output value becomes substantially the same as the input value, and it is possible to avoid the output from decreasing when it fails.

Further, the distance L from the mounting surface 8 of the hydraulic booster to the vehicle body to the mounting surface 11 to the master cylinder 10 is much shorter than that of the conventional hydraulic booster, and the size of the vehicle is small. Can greatly contribute to the realization. FIG. 5 is a block diagram of an embodiment showing another embodiment of the present invention by a link mechanism.
In the embodiment shown in FIG. 5, the intermediate point A of the input lever 4 is pivotally supported by the case 1 as a support point, and further the lower end C point of the input lever 4 is pivotally connected to the output lever 2. It is characterized by having done.

The boosting piston 6 is connected to a point E, which is before the point D to which the output member 3 of the output lever 2 is connected. Furthermore, the control valve 7 supports the input lever 4 on the case 1
It is connected to the point F on the output lever 2, which is near the point. Also in the embodiment of FIG. 5, if the distances a to d between the points are determined as shown in the figure, the same boosting ratio as that of the embodiment shown in FIG. 4 is obtained.

[0030]

As described above, according to the present invention, the distance between the vehicle body mounting surface and the master cylinder mounting surface of the hydraulic booster is shortened so that the entire length of the entire apparatus including the master cylinder is increased. Can be shortened. Also, since the input is transmitted to the control valve by the link mechanism to control the booster hydraulic pressure and the force of the booster piston is transmitted to the master cylinder side via the link mechanism, the friction resistance of the hydraulic seals does not matter. , The proportional accuracy between the input and output is high, and a good accuracy feeling can be obtained.

Further, since the input stroke can be made smaller than the output stroke, it is possible to prevent a drastic output decrease when the output member is directly pressed by the input member when the hydraulic pressure is lost, thereby ensuring high safety.

[Brief description of drawings]

FIG. 1 is an explanatory sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a sectional view of an embodiment of a control valve for controlling boosting hydraulic pressure according to the present invention.

FIG. 4 is an explanatory diagram showing the link configuration of FIG.

FIG. 5 is an explanatory diagram showing another embodiment of the present invention in a link configuration.

[Explanation of symbols]

 1: Case 2: Output lever 3: Output member 4: Input lever 5: Input member 6: Boosting piston 7: Control valve 8: Mounting surface on vehicle body 9: Mounting plate 10: Master cylinder 11: Mounting on master cylinder Surface 12, 15, 18, 25, 29: Shaft 13: Guide groove 14, 19: Roller 16: Receiving part 17: Brake pedal 20: Connection guide part 21, 37: Return spring 22: Boost cylinder 23: Cup seal 24 : Hydraulic chamber 26: Piston rod 27: Arm 28: Knob 30: Valve lever 32: Spool 33: Connection groove 34: Valve sleeve 35, 36: Land 38: Motor 39: Hydraulic pump 40: Accumulator 41: Leather tank

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[Procedure amendment]

[Submission date] July 30, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

That is, the case 1 of the hydraulic booster is provided with the input lever 4 supporting the fulcrum point A, and the point B at one end of the input lever 4 can be connected to the brake pedal via the input member 5. , The output lever 2 is swingably connected at an intermediate point C. The output lever 2 is connected to the output member 3 at a point D on the master cylinder side, and is connected to the boosting piston 6 at a point E outside the point D.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

As shown in FIG. 3, the upper end of the valve lever 30 is fitted into a connecting groove formed in the take-out portion of the spool 32 of the control valve 7 so that the output lever moves to the spool 32 via the valve lever 30. It is transmitted. The control valve 7 has a valve sleeve 34 incorporated in the case 1, and a spool 32 slidably incorporated in a shaft hole of the valve sleeve 34. A pump port P, a tank port T, and a control port C are formed on the valve sleeve 34 . The spool 32 has lands 35 and 36 at two locations, and the land 35 serves to provide the pump port P at the neutral position in the drawing.
The control port C is closed, and the control port C is opened to the tank port T. The land 36 partitions the tank port T and the pump port P. When the spool 32 moves to the right, the land 35 communicates the pump port P with the control port C and supplies the control hydraulic pressure to the hydraulic pressure chamber 24 of the booster piston 6. The spool 32 is pressed by a return spring 37 provided on the right side so as to return to the pressure reducing position .

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

[0027] Runimokakawarazu be shorter than the output stroke input stroke in this way, any chance, even when the boosting action by the liquid pressure is failure for booster piston 6 is lost, the movement of the input lever 4 Since it can be mechanically directly transmitted to the output lever 2 and the strokes of the input member 5 and the output member 3 are approximately one-to-one, the output value is also approximately the same as the input value, and the output is output when a failure occurs due to the shortened stroke. It is possible to avoid the decrease of the value.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction content]

Furthermore, it is possible to less than the output stroke input stroke can be guaranteed high to prevent extreme output reduction safety by pressing directly output member by the input member when Recessed liquid圧失.

[Procedure Amendment 5]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 6]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (3)

[Claims] 1. A hydraulic booster for a vehicle brake, which is provided between a master cylinder and a brake pedal and boosts a pedaling force to transmit to the master cylinder, an output lever 2 connected to an output member 3. And an input lever 4 connected to the input member 5, and the input lever 4 is attached to the case 1
Hydraulically boosting a vehicle brake characterized in that the output lever 2 and the input lever 3 are swingably connected to each other, and the output lever 2 and the boosting piston 6 are further connected to each other. apparatus. 2. The vehicle hydraulic booster according to claim 1, wherein the output member 2 is guided by a guide groove 13 provided in the case 1. Pressure booster. 3. A hydraulic booster for a vehicle according to claim 1, wherein a shift amount between the input lever 4 and the output lever 2 in a swinging direction is detected, and the shift amount is detected between the input lever 4 and the case 1. A hydraulic booster for a vehicle brake, characterized in that power is transmitted from an output lever 2 near a supporting portion to a control valve 7 of a boosting piston 6.