JPH10147224A - Brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake with braking liquid pressure applied from an outside liquid pressure source to a wheel cylinder in accordance with the stepped condition of a brake pedal so that a braking feeling similar to a mechanically braking feeling is given to a driver during braking operation without an unfamiliar feeling. SOLUTION: A stepping force sensor 54 is provided to detect stepping force on a brake pedal 1. A damping member 53 is provided between the stepping force sensor 54 and the brake pedal 1 to damp stepping force on the brake pedal 1. A stroke sensor 52 is provided to detect the displacement amount of the brake pedal 1. When the displacement amount of the brake pedal 1, when stepped, does not exceed a preset value, braking liquid pressure is applied from an outside liquid pressure source to a wheel cylinder in accordance with a detection signal from the stroke sensor 52. When the displacement amount of the brake pedal 1 exceeds a preset value, the braking liquid pressure is applied from the outside liquid pressure source to the wheel cylinder in accordance with the detection signal from the stepping force sensor 54.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake provided on a vehicle such as an automobile.

[0002]

2. Description of the Related Art In recent years, as a brake fluid pressure control device for controlling a fluid pressure of a brake for a vehicle such as an automobile, a device provided with an external fluid pressure supply source is known. Specifically, the spool of the hydraulic control valve provided between the external hydraulic pressure supply source and the wheel cylinder is displaced toward the pressure increasing side by the solenoid according to the master cylinder pressure generated based on the operation amount of the brake pedal. Thus, the brake hydraulic pressure from the external hydraulic pressure supply source acts on the wheel cylinder. By the way, this type of brake is provided with a stroke simulator consisting of an accumulator for releasing the master cylinder pressure in order to give the brake depression feeling when the brake pedal is depressed.

[0003]

However, in the above-mentioned device, there is a slight discrepancy in the depressing comfort of the brake pedal as compared with a general mechanical brake in which the hydraulic pressure of the master cylinder is directly applied to the wheel cylinder. As a result, there is a problem that the driver feels strange. In other words, in the case of a general mechanical brake,
As shown in FIG. 4, when the brake pedal is depressed,
After the play of the pedal and the invalid input of the master cylinder are exceeded, the rate of increase of the pedal effort gradually increases as the pedal stroke increases in the weak brake range,
When the braking force exceeds the weak braking range, the pedaling force tends to greatly increase with respect to the pedal stroke. On the other hand, in the case of the above device, as shown in FIG. After the input is exceeded, the stroke simulator operates and the pedal stroke and the pedal effort are consistently proportional.As described above, when the brake is applied, the driver feels uncomfortable. There was a fear that it would.

[0004] The present invention has been made in view of the above circumstances, and has as its object to provide a brake that does not make a driver feel uncomfortable when the brake is operated.

[0005]

In order to achieve the above object, a brake according to the present invention has a brake pedal having an input shaft for supplying a braking force to a wheel cylinder, and a brake pedal provided on the input shaft. A cushioning member for buffering the pedaling force applied to the brake pedal, a stroke sensor provided between the buffering member and the brake pedal for detecting a displacement of the brake pedal, and detecting a pedaling force when the brake pedal is depressed. A treading force sensor, an external hydraulic pressure source for supplying braking hydraulic pressure to the wheel cylinder, and a wheel provided from the external hydraulic pressure source provided in a pipe between the external hydraulic pressure source and the wheel cylinder. A hydraulic pressure control valve for increasing or decreasing the brake hydraulic pressure to the cylinder, and a displacement amount detected by the stroke sensor and a pedaling force detected by the pedaling force sensor. And Zui is characterized by comprising a control unit for controlling the pressure control valve.

According to a second aspect of the present invention, in the brake according to the first aspect, when the amount of displacement of the brake pedal is less than a predetermined value, the control unit reduces the amount of displacement detected by the stroke sensor. The brake hydraulic pressure is supplied from the corresponding external hydraulic pressure supply source to the wheel cylinder, and after the brake hydraulic pressure becomes equal to or more than the predetermined value, the wheel is supplied from the external hydraulic pressure supply source according to the pedaling force detected by the pedaling force sensor. The hydraulic pressure control valve is controlled so as to supply the brake hydraulic pressure to the cylinder.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a brake according to an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a brake pedal. The master cylinder 2 is provided on the brake pedal 1 via a rod 50 provided with a buffer device 51 described later. Note that reference numeral 40
Is a reservoir provided in the master cylinder 2.
Reference numeral 3 denotes a wheel cylinder that generates a braking force by hydraulic pressure, reference numeral 4 denotes an external hydraulic pressure source, and reference numeral 5 denotes an external hydraulic pressure source 4 based on the output of the master cylinder 2.
A hydraulic pressure control valve 30 for adjusting the pressure acting on the wheel cylinder 3 from the wheel cylinder 3 by controlling the driving of the hydraulic pressure control valve 5 to control the hydraulic pressure from the external hydraulic pressure supply source 4 It is a controller ECU (control unit) for supplying to the ECU.

The internal structure of the external hydraulic pressure supply 4 will be described. Reference numeral 4a denotes a hydraulic pump.
a is driven by a motor 4c to generate a hydraulic pressure. An accumulator 4b is connected to the output side of the hydraulic pump 4a so as to store the generated high hydraulic pressure. The hydraulic pump 4a is provided with a reservoir 4
The liquid sucked from d is pressurized and supplied to the liquid pressure control valve 5. Reference numeral 4E denotes a pressure sensor for detecting the pressure in the accumulator 4b, and a controller E based on the detection result from the pressure sensor 4E.
When the pressure of the accumulator 4b becomes equal to or lower than a predetermined value, the CU 30 drives the motor 4c to
Pressurization is performed by a. Also,
Reference numeral 4F indicates that when a hydraulic passage opening / closing valve 29 described later is opened,
It is a relief valve for releasing the hydraulic pressure from the accumulator 4b or the hydraulic pump 4a to the reservoir 4d.

Next, the structure of the hydraulic control valve 5 will be described. Reference numeral 11 denotes a body, and a valve hole 12 is provided inside the body 11, and a hydraulic pressure supply port 13, a drain port 14, and an output port 15 communicating with the valve hole 12 are provided. It is open in the valve hole 12. That is, the hydraulic pressure supply port 1
3 is connected to an external hydraulic pressure supply source 4, the drain port 14 communicates both ends of the valve hole 12 with each other, is connected to a reservoir 4d and is opened to the atmosphere, and the output port 15 is connected to a hydraulic amplification device 31 to be described later. And a fail-safe valve 8 connected to the wheel cylinder 3.

A spool 16 is slidably housed in the valve hole 12. The center of the spool 16 is reduced in diameter, and forms an annular communication groove 16a for communicating the hydraulic pressure supply port 13 with the output port 15. By providing the annular communication groove 16a, a variable throttle s is formed between the hydraulic pressure supply port 13 and the spool 16, and a variable throttle t is defined between the drain port 14 and the spool 16. Is formed. Therefore, when the spool 16 moves to the left in the figure, the variable throttle s opens and the variable throttle t closes, and the pressure at the output port 15 increases. When the spool 16 moves to the right in the figure, the pressure increases. Decrease.

The output of the output port 15 is connected to a reaction chamber 18 at one end of the hydraulic pressure control valve 5 through a pipe 17 branched from a pipe 32 toward the wheel cylinder 3. A reaction force generating means 19 is provided in the force chamber 18. The reaction force generating means 19 is fitted into the end of the valve hole 12, and a through hole provided in the center has
A pin 20 protruding from the center of the end of the spool 16 is slidably inserted. Further, a compression spring 21 is provided between the reaction force generating means 19 and the spool 16 as means for applying an elastic force to the spool 16 rightward in the drawing.

At the other end of the pressure control valve 5, a solenoid 22 is provided. This solenoid 22
A mover 23 provided coaxially with the valve hole 12 and movably in the axial direction, and a coil 24 and a yoke 2 provided to apply a thrust to the mover 23 in the axial direction.
5 and a compression spring 26 interposed between the mover 23 and the yoke 25 to apply an elastic force to the left in the figure.

In addition, a line between the accumulator 4b of the external hydraulic pressure supply source 4 and the hydraulic pressure supply port 13 of the hydraulic pressure control valve 5 having the above-described structure is provided with a fluid that is opened and closed by a signal from the controller ECU 30. A pressure passage opening / closing valve 29 is provided. That is, by the hydraulic pressure passage opening / closing valve 29,
A hydraulic pressure supply path from the external hydraulic pressure supply source 4 to the hydraulic pressure control valve 5 is opened and closed.

The hydraulic pressure amplifying device 31 includes a cylinder body 41 having two cylinder portions 41a and 41b having different diameters, a large-diameter plunger portion 34a and a small-diameter plunger portion 3.
4b, the large-diameter plunger portion 34
a is a large-diameter cylinder portion 41a, and a small-diameter plunger portion 34b
The plunger body 34 is slidably disposed on the small-diameter cylinder portion 41b. The large-diameter cylinder portion 41a and the large-diameter plunger portion 34
a is defined as the input-side hydraulic chamber 33, the small-diameter cylinder portion 41b and the small-diameter plunger portion 34b.
The space defined by the above is an output side hydraulic chamber 35. The output port 15 of the hydraulic pressure control valve 5 is connected to the input-side hydraulic chamber 33 via a flow path 32, and the output-side hydraulic chamber 35 is connected to a fail-safe valve 8 are connected.

A compression spring is provided in the output side hydraulic chamber 35, and the plunger body 34 is urged toward the large-diameter cylinder portion 41a by the compression spring.

An external hydraulic pressure source 4 is connected to the input hydraulic chamber 33 of the hydraulic amplifying device 31 through a hydraulic control valve 5.
, The pressurized brake fluid is supplied, and the hydraulic pressure causes the plunger body 34 to be pressed and slid in the direction of arrow A in the figure against the urging force of the compression spring. As a result, the output-side hydraulic chamber 35 is compressed by the small-diameter plunger portion 34b, and the internal brake fluid is pressurized and sent to the fail-safe valve 8 via the flow passage 36.

Here, the hydraulic pressure of the brake fluid sent out from the output side hydraulic chamber 35 through the flow path 36 is increased by the ratio of the areas of the respective plunger portions 34a and 34b. That is, the relationship between the hydraulic pressure Pin in the input-side hydraulic chamber 33 and the hydraulic pressure Pout in the output-side hydraulic chamber 35 depends on the input-side hydraulic chamber 3.
3, the pressure receiving area of the large diameter plunger portion 34a is Ain, and the pressure receiving area of the small diameter plunger 34b of the output side hydraulic chamber 35 is A.
If it is out, it can be expressed by the following equation.

Pout = Ain / Aout · Pin

That is, the brake fluid is pressurized by the ratio of the respective pressure receiving areas of the large diameter plunger 34a and the small diameter plunger 34b.

A line 43 from the master cylinder 2 is connected to the fail-safe valve 8 together with the line 36. This fail-safe valve 8 has a pipe 3
6 is connected, and is driven by the application of hydraulic pressure from this line 27 to cut off communication between the line 43 from the master cylinder 2 and the wheel cylinder 3 and Road 36 to wheel cylinder 3
And the hydraulic pressure from the conduit 36 acts on the wheel cylinder 3. Further, if the hydraulic pressure from the pipe 36 decreases for some reason during the operation of the brake, the hydraulic pressure is not applied to the fail-safe valve 8 from the pipe 27, so that the fail-safe valve 8 is provided with a spring or the like. And the communication between the pipe 36 and the wheel cylinder 3 is cut off.
3 to the wheel cylinder 3 and the master cylinder 2
Is applied directly to the wheel cylinder 3 to generate a braking force. In the drawing, reference numeral 10 denotes a pressure sensor for detecting wheel cylinder pressure, and reference numeral 44 denotes a wheel speed sensor for detecting wheel speed. Detection signals from the pressure sensor 10 and the wheel speed sensor 44 correspond to stroke sensors described later. 52, transmitted to the controller ECU 30 together with the detection signal of the pedaling force sensor 54, and based on the detection signals of these sensors, the controller ECU 30 controls the driving of the hydraulic pressure control device 5 to perform anti-skid control;
Various controls such as traction control are performed.

Next, a description will be given of the shock absorber 51 provided between the brake pedal 1 and the master cylinder 2 of the brake fluid pressure control device having the above configuration. As shown in FIG. 2, the shock absorber 51 includes a stroke sensor 52, a shock absorbing member 53, and a treading force sensor 54.
The brake pedal 1 is provided in order from the side. The stroke sensor 52 detects a stroke amount of the brake pedal 1 when the brake pedal 1 is depressed, and a detection signal from the stroke sensor 52 is transmitted to the controller ECU 30. The cushioning member 53 is made of an elastic material such as a compression spring, and is compressed and elastically deformed when the brake pedal 1 is depressed. When the brake pedal 1 is depressed, the depression force sensor 54 detects the depression force, and transmits a detection signal to the controller ECU 30.

According to the brake fluid pressure control device provided with the shock absorbing device 51, when the driver depresses the brake pedal 1 to operate the brake, the shock absorbing member 53 constituting the shock absorbing device 51 is operated by the depressing force. Is elastically deformed, the brake pedal 1 moves,
The stroke is detected by the stroke sensor 52, and a detection signal is transmitted to the controller ECU 30. At this time, the pedaling force sensor 54 detects the pedaling force of the brake pedal 1 and outputs a detection signal to the controller ECU 30.

When the controller ECU 30 detects that the brake pedal 1 is depressed based on a detection signal from the stroke sensor 52, it supplies a control current to the hydraulic passage opening / closing valve 29 as described above, The pressure passage opening / closing valve 29 is opened to connect the flow path between the external hydraulic pressure supply source 4 and the hydraulic pressure control valve 5 and to control the exciting current of the coil 24 of the solenoid 22 in accordance with the stroke of the brake pedal 1 to be movable. By moving the child 23, the spool 16 is moved in the same direction. As a result, the variable throttle s of the hydraulic pressure control valve 5 is opened, and the annular communication groove 16a and the hydraulic pressure supply port 13 are opened.
The brake fluid pressure from the output port 15 is further pressurized by the fluid pressure amplifying device 31 and supplied to the wheel cylinder 3 to brake the wheels.

Further, the brake pedal 1 is depressed,
When the cushioning member 53 is completely compressed, the brake pedal 1
After that, the controller ECU 30 controls the hydraulic pressure control valve 5 based on the detection signal from the pedaling force sensor 54, and the wheels are braked according to the pedaling force of the brake pedal 1. That is, according to the brake fluid pressure control device of the present embodiment, as shown by the solid line in FIG.
As a result, the pedaling force is absorbed, and the pedaling force gradually increases with respect to the pedal stroke. After that, when the cushioning member 53 is completely compressed and the brake pedal 1 is no longer displaced,
Only the pedal force increases.

That is, when the driver depresses the brake pedal, the pedaling force is absorbed to generate a predetermined stroke, and the brake feeling of a mechanical brake that directly applies hydraulic pressure from the master cylinder 2 to the wheel cylinder 3 (see FIG. 4), which makes it possible to minimize the driver's discomfort when the brakes are applied. Further, since the master cylinder 2 is not driven, there is no invalid input of the master cylinder 2 and detection from a lower depression state can be performed, thereby improving the responsiveness of the hydraulic control. . In the weak braking range, the hydraulic pressure is controlled based on the stroke detection signal from the stroke sensor 52, and thereafter, the hydraulic pressure is controlled based on the pedaling force detection signal from the pedaling force sensor 54. Since it is performed in a system, the reliability of detection of depression can be greatly improved.

The cushioning member 53 may be made of a non-linear material such as rubber or a multi-stage spring, that is, an elastic material that requires a progressively larger compressive force as it is compressed. As shown by the chain line of 3,
The relationship between the pedal stroke and the pedaling force can be made closer to that of the mechanical brake (see FIG. 4), so that a better brake feeling can be obtained. In the present embodiment, the pedaling force sensor 54 is provided on the rod 50 between the cushioning member 53 and the master cylinder 2. However, the present invention is not limited to this, and if the pedaling force on the brake pedal 1 can be detected, the brake is applied. It may be provided at any position between the pedal 1 and the master cylinder 2.

[0027]

As described above, according to the brake of the present invention, the following effects can be obtained. In the weak braking range exceeding the play of the brake pedal, the pedaling force is absorbed by the cushioning member and the pedaling force increases gently with respect to the pedal stroke.After that, the cushioning member is completely compressed and the brake pedal is no longer displaced. Means that only the treading force increases. In other words, when the driver depresses the brake pedal, the pedal absorbs the depressing force to generate a predetermined stroke, which can approximate the braking feeling of a mechanical brake that directly applies hydraulic pressure from the master cylinder to the wheel cylinder. As a result, it is possible to minimize the driver's discomfort during the operation of the brakes, and furthermore, since the master cylinder is not driven, there is no invalid input of the master cylinder, and detection from a lower depression state is possible. Accordingly, the responsiveness of the hydraulic control can be improved. Further, when the depression amount of the brake pedal is equal to or less than a predetermined value, the hydraulic pressure is controlled based on the stroke detection signal from the stroke sensor, and thereafter, the hydraulic pressure is controlled based on the pedaling force detection signal from the pedaling force sensor. Since the detection of depression is performed by two systems, the reliability of detection of depression can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a hydraulic diagram of a brake illustrating an overall configuration of a brake according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram around a brake pedal and a master cylinder illustrating the configuration and structure of a shock absorber provided in the brake according to the embodiment of the present invention.

FIG. 3 is a graph showing a relationship between a pedal stroke and a pedaling force in the brake according to the embodiment of the present invention.

FIG. 4 is a graph showing a relationship between a pedal stroke and a pedaling force in a mechanical brake that directly applies a hydraulic pressure of a master cylinder to a wheel cylinder.

FIG. 5 is a graph showing a relationship between a pedal stroke and a pedaling force in a brake provided with an accumulator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake pedal 3 Wheel cylinder 4 External hydraulic pressure supply source 30 Controller ECU (control part) 52 Stroke sensor 53 Buffer member 54 Depressing force sensor

Claims (2)

[Claims] 1. A brake pedal having an input shaft for supplying a braking force to a wheel cylinder, a buffer member provided on the input shaft for buffering a pedaling force on the brake pedal, the buffer member and the brake A stroke sensor provided between the brake pedal and the brake pedal to detect a displacement amount of the brake pedal; a tread force sensor for detecting a tread force when the brake pedal is depressed; and an external hydraulic pressure supply source for supplying a brake hydraulic pressure to the wheel cylinder. A hydraulic pressure control valve provided in a conduit between the external hydraulic pressure supply source and the wheel cylinder to increase or decrease a braking hydraulic pressure from the external hydraulic pressure supply source to the wheel cylinder; A control unit for controlling the hydraulic pressure control valve based on the amount of displacement to be applied and the treading force detected by the treading force sensor. Brake. 2. The control unit, when the displacement amount of the brake pedal is less than a predetermined value, braking from the external hydraulic pressure supply source to the wheel cylinder according to the displacement amount detected by the stroke sensor. After the hydraulic pressure is supplied and becomes equal to or greater than the predetermined value, the hydraulic pressure control is performed so as to supply the brake hydraulic pressure from the external hydraulic pressure supply source to the wheel cylinder according to the pedaling force detected by the pedaling force sensor. The brake according to claim 1, wherein the valve is controlled.