JPH09226565A - Foot-stamping force measurement device for brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure accurate foot-stamping force over a long term. SOLUTION: A foot-stamping force measurement device 201 for measuring a foot-stamping force applied to a brake pedal 99 has the first sensor 202 for measuring the brake fluid pressure of a master cylinder 101, the second sensor 203 for measuring differential pressure between the constant pressure chamber 7 and the variable pressure chamber 8 of a brake booster 1, and a control device 204. This control device 204 finds the integrated value P1 (action force of brake fluid pressure applied to piston 104) of the brake fluid pressure from the measurement value of the first sensor 202 and the pressure receiving area of the piston 104. Also, the control device 204 finds the integrated value P2 (output of brake booster) of the differential pressure from the measurement value of the second sensor 203 and the pressure receiving area of a power piston 5. Furthermore, the output P2 and a resistance value F preliminarily stored in the control device 204 are subtracted from the action force P1, thereby providing foot-stamping force applied to the brake pedal 99.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device provided with a brake booster and a master cylinder, and more particularly to a pedal force measuring device for a brake device which can obtain the pedal force applied to a brake pedal. .

[0002]

2. Description of the Related Art A conventional brake system generally comprises a brake booster that boosts a pedaling force applied to a brake pedal, and a master cylinder that is operated by the brake booster to generate a brake fluid pressure. The master cylinder includes a piston that is provided in the cylinder so as to be movable back and forth and that generates the brake fluid pressure when the master cylinder moves forward. Further, the brake booster is provided with a valve body provided in the shell so as to be movable back and forth, an output shaft for advancing the piston of the master cylinder by advancing the valve body, and a constant pressure chamber provided in the shell for the valve body. A power piston that is partitioned into a variable pressure chamber and a valve mechanism that is housed in the valve body and that is operated by the brake pedal to generate a pressure difference between the constant pressure chamber and the variable pressure chamber are provided. By the way, in recent years, it has been attempted to assist the braking of the vehicle by using a control device such as a computer or to improve the operation feeling of the brake (Japanese Patent Laid-Open No. 5-162624). In such a case, in order to obtain the brake fluid pressure corresponding to the pedal effort applied to the brake pedal, a pedal effort measuring device for measuring the pedal effort applied to the brake pedal is required.

[0003]

However, conventionally, there is no suitable pedaling force measuring device. For example, a pedaling force can be attached to a brake pedal and the pedaling force can be measured from the strain of the strain gauge. And was inferior in durability. Therefore, in view of such circumstances, the present invention provides a pedaling force measuring device for a brake device, which is capable of more accurately measuring the pedaling force applied to a brake pedal and has excellent durability.

[0004]

That is, according to the present invention, in the above-mentioned conventional brake device, a first sensor for measuring the brake fluid pressure and a second sensor for measuring the differential pressure between the constant pressure chamber and the variable pressure chamber. In addition, a control device for inputting the measurement value of the first sensor and the measurement value of the second sensor to obtain the pedal effort applied to the brake pedal from the measurement values is provided. At this time, by the control device, from the integrated value P1 of the measured value measured by the first sensor and the pressure receiving area of the piston of the master cylinder, the integrated value of the measured value measured by the second sensor and the pressure receiving area of the power piston. P
By subtracting 2 and the predetermined resistance value F, the pedaling force applied to the brake pedal can be obtained.

[0005]

According to the above configuration, the control device is the first
The acting force P1 of the brake fluid pressure applied to the piston of the master cylinder can be obtained from the integrated value P1 of the measurement value measured by the sensor and the pressure receiving area of the piston of the master cylinder. Further, the output P2 of the brake booster can be obtained from the integrated value P2 of the measurement value measured by the second sensor and the pressure receiving area of the power piston. On the other hand, the total resistance value F such as the repulsive force of each return spring and the frictional resistance of each part that biases and holds the piston of the master cylinder and the power piston of the brake booster in the non-actuated position may be measured in advance. Therefore, the control device can obtain the pedaling force applied to the brake pedal by subtracting the output P2 and the resistance value F from the acting force P1.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. In FIG. 1, reference numeral 1 is a brake booster for boosting the pedal effort applied to a brake pedal 99, and 101 is a brake booster 1. It is a tandem master cylinder that converts the applied pedal force into brake fluid pressure and supplies it to the wheel cylinders. The brake booster 1 is a single type brake booster having a conventionally known structure, and a substantially cylindrical valve body 4 slides in a sealed container formed by a front shell 2 and a rear shell 3. A power piston 5 provided freely on the outer periphery of the valve body 4 and a diaphragm 6 attached to the rear side of the valve body 4 divides the sealed container into a constant pressure chamber 7 on the front side and a variable pressure chamber 8 on the rear side. There is. A valve mechanism 9 for switching a fluid circuit is accommodated in the valve body 4, and the valve mechanism 9 includes an annular first valve seat 10 formed on the inner peripheral side of the valve body 4,
An annular second valve seat 12 formed at the right end of a valve plunger 11 slidably fitted in the valve body 4, and a valve body seated on both valve seats 10 and 12 from the right side of the drawing by a spring 13. 14 and. And the first
The outer peripheral side of the valve seat 10 is communicated with the constant pressure chamber 7 through an axial constant pressure passage 15 formed in the valve body 4, and the constant pressure chamber 7 is provided with a negative pressure introducing pipe 16 provided in the front shell 2.
A negative pressure is constantly introduced into the constant pressure chamber 7 by communicating with an intake manifold of an engine (not shown) via the. An intermediate portion between the first valve seat 10 and the second valve seat 12 is communicated with the variable pressure chamber 8 through a variable pressure passage 17 formed in the valve body 4 in the radial direction, and further than the second valve seat 12. The inner peripheral side is communicated with the atmosphere via a pressure passage 18 formed in the valve body 4. The right end of the valve plunger 11 is pivotally connected to the tip end of the input shaft 20 which is interlocked with the brake pedal 99, so that when the brake pedal 99 is depressed from the inoperative state, the input shaft 20 is not moved. The valve mechanism 9 can be switch-controlled via the valve mechanism. A plate plunger 21 and a reaction disc 22 are sequentially arranged on the left side of the valve plunger 11, and the reaction disc 22 is provided in a recess formed in a base portion of an output shaft 23 slidably provided on the valve body 4. It is housed. The left end of the output shaft 23 is kept airtight via a seal member 24 and is projected to the outside to interlock with the piston 102 of the tandem master cylinder 101. A return spring 25 is mounted between the valve body 4 and the front shell 2 so that the valve body 4 can normally be held in the inoperative position shown. A spring 26 is also mounted between the valve body 4 and the input shaft 20 so that the input shaft 20 can be held in the inoperative position in the drawing.

Next, the tandem master cylinder 10 is used.
1 also has a conventionally known configuration, and a front shell 2
Two pistons 102, 104 are fitted in a cylinder 103 which is integrally connected to the shaft portion of the
05 and 106 hold both pistons 102 and 104 in the non-actuated position shown in the figure. The piston 102 on the rear side is interlocked with the output shaft 23 of the brake booster 1 as described above. In the cylinder 103, brake fluid pressure chambers 107 and 108 are formed on the left side of the pistons 102 and 104, respectively, and the brake fluid pressure chambers 107 and 108 are connected to the wheels (not shown) via pipes 109 and 109. It communicates with the cylinder. Further, reservoir passages 110 and 111 are connected to the brake fluid pressure chambers 107 and 108, respectively, and the brake fluid pressure chambers 107 and 108 of the reservoir passages 110 and 111 are communicated with each other.
Is opened when the pistons 102, 104 are in the non-actuated position, and the brake fluid pressure chamber 107,
It is adapted to communicate with each of 108. On the other hand, when the pistons 102, 104 are advanced from the non-actuated state, the openings of the reservoir passages 110, 111 to the brake fluid pressure chambers 107, 108 are formed in the pistons 1 respectively.
It is designed to be closed by 02, 104. The two reservoir passages 110 and 111 are combined into one reservoir passage 112 and communicate with a reservoir tank (not shown).

Further, the pedal effort measuring device 201 for measuring the pedal effort applied to the brake pedal 99 is provided with a first sensor 202 for measuring the brake fluid pressure in one pipe 109 of the tandem master cylinder 101, and the brake The booster 1 includes a second sensor 203 that measures the differential pressure between the constant pressure chamber 7 and the variable pressure chamber 8. The first
A normal oil pressure sensor can be used as the sensor 202.
As the second sensor 203, an atmospheric pressure sensor that measures the pressure of gas, that is, an atmospheric pressure sensor that measures the differential pressure between the pressure of the gas and the atmospheric pressure is used, and the pressure in the constant pressure chamber 7 is The pressure in the variable pressure chamber 8 may be applied to the other side. Since such hydraulic pressure sensor and atmospheric pressure sensor are already known in the related art, the description of their specific configurations will be omitted.
Then, the measurement value measured by the first sensor 202 and the measurement value measured by the second sensor 203 are
4 is input. This control device 204
The pressure-receiving area of the piston 104 on which the brake fluid pressure measured by the first sensor 202 acts is stored in advance, and the pressure-receiving area of the power piston 5 on which the differential pressure measured by the second sensor 203 acts. Is also remembered. Further, the repulsive force of the springs 105 and 106 for biasing and holding the pistons 102 and 104 of the tandem master cylinder 101 to the non-actuated position, the power piston 5 of the brake booster 1 and the input shaft 20 to the non-actuated position. The overall resistance value F acting in the direction opposite to the pedal force direction of the brake pedal 99, such as the repulsive force of the return spring 25 and the spring 26 that holds the urging force and the frictional resistance of each part, is measured in advance,
This resistance value F is also stored in the control device 204.

Therefore, when the brake pedal 99 is depressed and the brake booster 1 and the tandem master cylinder 101 are operated, the control unit 204 inputs each measured value from the first sensor 202 and the second sensor 203. First, the measured value of the first sensor 202 and the piston 104
The integrated value P1 is obtained from the pressure receiving area of the power sensor 5 and the integrated value P2 is obtained from the measured value of the second sensor 203 and the pressure receiving area of the power piston 5. Next, if the integrated value P2 (output of the brake booster 1) and the resistance value F are subtracted from the integrated value P1 (the acting force of the brake fluid pressure applied to the piston 104), the brake pedal 99 is obtained.
It is possible to obtain the pedaling force applied to. in this way,
Since the pedaling force applied to the brake pedal 99 is obtained based on the brake fluid pressure and the differential pressure between the constant pressure chamber and the variable pressure chamber, the pedaling force can be highly accurately compared with the case where a strain gauge is used. In addition, stable measurement can be performed over a long period of time.

In the above embodiment, the constant pressure chamber 7 and the variable pressure chamber 8 are controlled by the second sensor 203 provided outside the shells 2 and 3.
However, the second sensor may be provided in the power piston 5 or the valve body 4 and the signal line thereof may be drawn to the outside of the shells 2 and 3. The second sensor 203
Is composed of two atmospheric pressure sensors, one atmospheric pressure sensor measures the differential pressure between the atmospheric pressure and the pressure inside the constant pressure chamber 7, and the other atmospheric pressure sensor measures the differential pressure between the atmospheric pressure and the pressure inside the variable pressure chamber 8. Make sure to measure the pressure difference between the constant pressure chamber 7 and the variable pressure chamber 8
You may make it obtain the differential pressure with.

[0011]

As described above, according to the present invention, the pedaling force applied to the brake pedal can be accurately measured for a long period of time.

[Brief description of drawings]

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

[Explanation of symbols]

1 ... Brake booster 4 ... Valve body 5 ... Power piston 6 ... Diaphragm 7 ...
Constant pressure chamber 8 ... Transformer chamber 9 ... Valve mechanism 25
Return spring 26 Spring 99 Brake pedal 101 Tandem master cylinder 102, 104
... Piston 103 ... Cylinder 105, 106
... Spring 201 ... Treading force measuring device 202 ... First sensor 203 ... Second sensor 204 ... Control device

Claims (3)

[Claims] 1. A brake booster that boosts a pedaling force applied to a brake pedal, and a master cylinder that is actuated by the brake booster to generate a brake fluid pressure, wherein the master cylinder is an internal cylinder. And a piston for generating the brake fluid pressure when the brake cylinder is moved forward, and the brake booster includes a valve body provided in the shell so that the brake hydraulic pressure can move forward and backward, and the master cylinder can be moved forward by the valve body. Output shaft for advancing the piston, a power piston provided in the valve body for partitioning the shell into a constant pressure chamber and a variable pressure chamber, and a power piston housed in the valve body and operated by the brake pedal to operate the constant pressure. In a brake device provided with a valve mechanism that generates a pressure difference between the pressure chamber and the variable pressure chamber The first sensor for measuring the brake fluid pressure, the second sensor for measuring the differential pressure between the constant pressure chamber and the variable pressure chamber, and the measurement value of the first sensor and the measurement value of the second sensor are input. A pedaling force measuring device for a brake device, comprising: a control device for obtaining a pedaling force applied to a brake pedal from the measured values. 2. The control device, based on an integrated value P1 of the measured value measured by the first sensor and the pressure receiving area of the piston of the master cylinder, the measured value measured by the second sensor and the pressure receiving area of the power piston. The pedaling force measurement of the brake device according to claim 1, wherein the pedaling force applied to the brake pedal is obtained by subtracting an integrated value P2 of the above and a predetermined resistance value F. apparatus. 3. The second sensor is provided in the power piston or the valve body, and the pressure in the constant pressure chamber and the pressure in the variable pressure chamber act on the second sensor. Alternatively, the pedal effort measuring device for the brake device according to claim 2.