JP2901388B2 - Modulator for anti-lock brake - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modulator for controlling a brake hydraulic pressure transmitted from a mass cylinder to a wheel brake in an antilock brake device for a vehicle.

[0002]

2. Description of the Related Art For example, a conventional modulator for an antilock brake will be briefly described with reference to FIG. The modulator 2 has an input hydraulic chamber 4 communicating with the master cylinder.
An output hydraulic chamber 6 that communicates with the wheel brakes, and a cut valve 8 that communicates and shuts off the two hydraulic chambers 4, 6.
An expander piston 10 is provided below the cut valve 8 to open and close the cut valve 8 and to change the volume on the output hydraulic pressure side. The expander piston 10 is configured such that a ring body 14 provided on a crank pin 12 as an eccentric member abuts on a lower portion thereof. The crank pin 12 is
One end is connected to a drive shaft 18 of the DC electric motor 16 by a crank 20.
And the other end is connected to a return spring 22 composed of a spiral spring. As shown in FIG. 6, the crank 20 is connected to a pinion 18a formed on the drive shaft 18 via an internal gear 20a.
A stopper 20b is provided on the outer periphery thereof.
When b contacts the modulator body 2a, the rotation angle of the crank pin 12 is restricted to a range of 180 ° between the top dead center and the bottom dead center (see FIG. 6). In addition, crankpin 12
Is always directed to the top dead center by the elastic force of the return spring 22 composed of a spiral spring, that is,
The expander piston 10 is urged by the ring body 14 in a direction to open the cut valve 8.

[0003] The modulator 2 configured as described above includes:
It works as follows. That is, during normal braking, the crank 20 is held at the top dead center by the return spring 22 and the modulator body 2a, and the ring body 14 of the crank pin 12 pushes up the expander piston 10. Therefore, the cut valve 8 is opened, and the brake hydraulic pressure is transmitted from the master cylinder to the caliper cylinder via the hydraulic pressure chambers 4 and 6. In this case, since the ring body 14 of the crank pin 12 is restrained at the top dead center (a position parallel to the displacement direction of the expander piston 10), even if the expander piston 10 is pressed by the brake oil pressure, the ring body No moment acts on 14 and the crankpin 12 does not rotate. On the other hand, when performing the antilock brake control, the drive shaft 18 of the DC electric motor 16 is rotated, and the crankpin 12 is rotated from the top dead center to the bottom dead center via the crank 20. As a result, the ring body 14 also rotates, and the expander piston 10 immediately descends following the ring body 14 by the brake oil pressure, and closes the cut valve 8. Thereafter, the volume of the output hydraulic chamber 6 is increased to reduce the brake hydraulic pressure transmitted to the caliper cylinder. When canceling the antilock brake control, the power supply to the DC electric motor 16 is stopped or the power is supplied in the reverse rotation direction, and the crank pin 12 is returned to the original position by the elastic force of the return spring 22 and the reverse rotation force of the DC electric motor 16. That is, it is returned to the top dead center, and the brake hydraulic pressure increases.

[0004]

In the modulator 2 for an anti-lock brake configured as described above,
There is a demand for smaller and lighter parts and improved performance.

In order to reduce the size and weight of the modulator 2, it is first conceivable to reduce the size of the DC electric motor 16. The DC electric motor 16 is required to reduce the required motor torque, that is, to reduce the maximum torque required when rotating the crankpin 12. In this case, the force acting on the crankpin 12 by the elastic force of the return spring 22 may be reduced. However, the return spring 22 of the modulator 2
Is of a spiral type, and since the elastic force increases in proportion to the rotation angle, it is difficult to reduce the maximum elastic force.

Further, in the modulator 2, it is desired to further improve the response. The responsiveness refers to the change speed of the brake oil pressure when switching from the normal braking state to the antilock brake control. That is, when switching to the antilock brake control, the rotation of the ring body 14 by the crank pin 12 causes the expansion piston 1 to rotate.
0 is displaced, the cut valve 8 closes, and the brake hydraulic pressure changes. At this time, since the ring body 14 is a rotational movement that starts to move from the top dead center, the displacement amount of the expander piston 10 abutting on the ring body 14 with respect to the rotation of the ring body 14 at a fixed angle is the top dead center. Smaller nearer. Accordingly, the displacement (opening → closing) of the cut valve 8 at the initial stage of switching is small, and the change of the brake oil pressure is also small.

SUMMARY OF THE INVENTION The present invention has been made to solve this kind of problem, and can reduce the size of a modulator for an anti-lock brake. It is an object of the present invention to provide a modulator for an anti-lock brake having a good response to an initial change of the brake.

[0008]

To achieve the above object SUMMARY OF THE INVENTION The present invention includes an input hydraulic pressure chamber communicating with the master cylinder, an output hydraulic chamber which communicates with the wheel brake, the input oil
Provided in a communication passage communicating the pressure chamber and the output hydraulic chamber .
The communication passage is opened by moving to the input hydraulic chamber side.
While moving to the output hydraulic chamber side,
A cut valve that blocks the passage, proceed to the output hydraulic pressure chamber side
Mounted for withdrawal constitutes the output hydraulic pressure chamber, while operating the valve opening of the cut valve by the one end to move to the input hydraulic pressure chamber side during normal braking, during anti-lock braking
The one end moves in a direction away from the input hydraulic chamber side.
Rutotomoni the cut valve is operated closed valve by part,
An expander piston for changing the volume of the output hydraulic chamber, and a biased piston connected to the other end of the expander piston.
A core member for moving the expander piston forward and backward.
Rotating crank and the expander piston
The eccentric member to move the
And a coil spring that presses and biases the expander piston.
90 ° <θs <with respect to the moving direction to the input hydraulic chamber side
The angle θs is set to 180 ° .

Further, communicating invention, which communicates with the input hydraulic pressure chamber, an output hydraulic chamber which communicates with the wheel brake, the input hydraulic chamber and the output hydraulic chamber which communicates with the master cylinder
It is provided in the passage and moves to the input hydraulic chamber side to
Open the communication passage and move to the output hydraulic chamber side
A cut valve for blocking the communication passage by the output
The output hydraulic chamber is configured to be able to move forward and backward on the hydraulic chamber side.
During normal braking, it moves to the input hydraulic chamber side and
Moving more the cut valve while operating the valve opening, in a direction away from the anti-lock brake at the input hydraulic chamber side
To the said cut valve by the one end portion is operated closed valve <br/> Rutotomoni, the expander piston to vary the volume of the output hydraulic pressure chamber, the other end of the expander piston
An eccentric member connected to the expander piston;
A crank which rotates so as to advance and retreat, the extract
In order to move the panda piston to the input hydraulic chamber side,
A coil spring for pressing biasing said eccentric member, the
Anti-lock from normal braking by expander piston
Rotation start angle of the eccentric member at the time of switching to braking
And a regulating member for regulating the said regulating member, wherein d
In the direction in which the Kispanda piston moves toward the input hydraulic chamber,
A line from the rotation axis of the crank to the eccentric member
The minute rotation start angle theta] p, wherein that you regulations 0 ° <θp ≦ 90 °.

[0010]

Since the coil spring is disposed at a predetermined angle with respect to the displacement direction of the expander piston, the elastic torque of the coil spring from top dead center to bottom dead center does not increase monotonously. When the direction of displacement of the eccentric member is substantially parallel to the direction of displacement of the coil spring, it becomes maximum and then decreases. Accordingly, the maximum elastic torque of the coil spring is reduced, and the size of the motor can be reduced, that is, the modulator for the antilock brake can be reduced in size.

Further, since the regulating means for regulating the upper limit position of the eccentric member to a position deviated by a predetermined amount from the top dead center toward the bottom dead center is provided, at the initial stage of switching from the normal braking state to the antilock brake control, The initial displacement of the expander piston due to the rotation of the eccentric member at a constant angle increases. Therefore, the change of the brake oil pressure at the initial stage of the switching, that is, the responsiveness is improved.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a modulator for an anti-lock brake according to the present invention. The same reference numerals are given to the same components as those in the conventional example, and the detailed description thereof will be omitted.

A ring body 1 as an eccentric member abutting on the expander piston 10 of the modulator 30 shown in FIG.
Reference numeral 4 is connected to a drive shaft that is rotated by a motor (not shown), and rotates around a rotation center 32. In this embodiment, stoppers 34 and 36 are provided so as to regulate the rotation angle of the ring body 14. Stoppers 34, 36
Accordingly, the upper limit position and the lower limit position of the rotational movement of the ring body 14 are regulated. Here, the upper limit position of the ring body 14 is set at an angle θp (0 ° <θp ≦ 90 °) from the displacement direction of the expander piston 10 which is a virtual top dead center.

The return spring 38 is composed of a coil spring and has a rotation angle θs (90) in the counterclockwise direction of rotation with respect to the direction of displacement of the expander piston 10.
° <θs <180 °). The return spring 38 has a sufficient elastic torque that does not cause the ring body 14 to rotate even when the expander piston 10 is given a downward pressing force by the brake oil pressure during normal braking.

The modulator 30 configured as described above
Works as follows.

At the time of normal braking of the modulator 30, the ring body 14 is at the upper limit position, the cut valve 8 is opened, and the brake hydraulic pressure is supplied from the master cylinder to the two hydraulic chambers 4,6.
Is transmitted to the caliper cylinder via Further, at the time of the anti-lock brake control operation, the ring body 14 is rotated by a motor (not shown), whereby the expander piston 10 moves down to close the cut valve 8 and increase the volume of the output hydraulic chamber 6. Brake oil pressure drops.

When the ring member 14 is rotated from the upper limit position to the lower limit position in the modulator 30 operating as described above, the torque generated in the motor is the displacement of the return spring 38 accompanying the rotation of the ring member 14, that is, the elastic force. The rotation center 32 of the ring body 14 and the return spring 3
This is a value obtained by multiplying the vertical distance to the load operating point 40 of No. 8.
In this embodiment, since the return spring 38 is disposed at an angle θs with respect to the displacement direction of the expander piston 10, the torque by the return spring 38 becomes maximum when the ring body 14 rotates to approximately the angle θs−90 °. If it rotates further, the value obtained by multiplying the elastic force of the spring by the vertical distance from the rotation center 32 to the load operating point 40 decreases, and conversely the torque value decreases. Therefore, as shown in FIG. 2, the torque does not monotonously increase with the increase in the rotation angle of the ring body 14 (see a 1 in FIG. 2), as in the return spring 22 composed of a conventional spiral spring. When the rotation angle is approximately the angle θs−90 °, the maximum torque value is shown, and thereafter the torque decreases (see b1 in FIG. 2). Therefore, as is apparent from FIG. 2, the required maximum torque value applied to the motor is also reduced, and the motor can be reduced in size and weight, that is, the modulator 30 can be reduced in size and weight. In the conventional example and the present embodiment,
When the required motor torque is the same, the torque Ts of the ring body 14 at the upper limit position, that is, the elastic force of the return spring 38 can be set strong as shown in FIG. Therefore, the displacement of the expander piston 10 due to the brake oil pressure during the normal braking of the modulator 2 can be more reliably prevented.

Further, in this embodiment, the stopper 3
4 to restrict the ring body 14 to the angle θp with respect to the displacement direction of the expander piston 10 at the upper limit position of the expander piston 10 (see FIG. 1), as shown in FIG. Angle parallel to the displacement direction of the expander piston 10 (θ = 0 °,
Ring body 14 at the upper limit position
The displacement amount S2 of the expander piston 10 with respect to the same angle θ at the start of the rotation is increased with respect to the conventional displacement amount S1. Therefore, when switching from the normal braking of the modulator 2 to the antilock brake control, the responsiveness of the expander piston 10 at the initial stage of the switching is further improved.

[0019]

According to the modulator for an anti-lock brake according to the present invention, the following effects can be obtained.

That is, in the modulator, since the coil spring is disposed at a predetermined angle with respect to the displacement direction of the expander piston, the coil spring is compressed by the rotation of the eccentric member for displacing the expander piston. The torque of the motor reaches its maximum value when the rotation angle of the eccentric member coincides with the predetermined angle of the coil spring arrangement, and decreases when it is rotated further. Therefore, the required maximum torque of the motor can be reduced, so that the motor, that is, the modulator can be downsized.

In addition, since there is provided a regulating means for displacing the upper limit position of the eccentric member from the top dead center toward the bottom dead center by a predetermined amount in the rotation direction, the displacement amount of the expander piston with respect to the angle change at the start of the rotation of the eccentric member is provided. Is big. Therefore, when switching from the normal braking of the modulator to the antilock brake control, the amount of change in the brake oil pressure at the initial stage of switching is increased, and the responsiveness is further improved.

[Brief description of the drawings]

FIG. 1 is an explanatory longitudinal sectional view of a modulator for an antilock brake according to the present invention.

FIG. 2 is a relationship diagram showing a change amount of a motor torque with respect to a rotation angle of an eccentric member in an antilock brake modulator according to the present invention and a conventional example.

FIG. 3 is a relation diagram showing a change amount of a motor torque showing the same maximum torque value with respect to a rotation angle of an eccentric member in the modulator for an antilock brake according to the present invention and a conventional example.

FIG. 4 is a relationship diagram showing a displacement amount of an expander piston with respect to a rotation angle of an eccentric member in an antilock brake modulator according to the present invention and a conventional example.

FIG. 5 is an explanatory longitudinal sectional view of an antilock brake modulator according to a conventional example.

FIG. 6 is a sectional view taken along line VI-VI in FIG. 5;

[Explanation of symbols]

 2, 30 modulator 8 cut valve 10 expander piston 14 ring body 22, 38 return spring 34, 36 stopper

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hidehiko Takase 1-4-1 Chuo, Wako-shi, Saitama Inside of Honda R & D Co., Ltd. (56) References JP-A-5-4567 (JP, A) JP-A Heisei 5-4568 (JP, A) JP-A-3-109154 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60T 8/32-8/86

Claims (2)

(57) [Claims] 1. A input hydraulic pressure chamber communicating with the master cylinder, an output hydraulic chamber which communicates with the wheel brake, the communication passage which communicates the input hydraulic chamber and the output hydraulic chamber
And moving to the input hydraulic chamber side to
Opening the passage and moving to the output hydraulic chamber side
A cut valve for shutting off the communication passage, and an output hydraulic pressure
Constitutes a chamber, and normally moves to the input hydraulic chamber side during braking.
While operating the valve opening of the cut valve by the one end,
Those who are separated from the input hydraulic chamber side during antilock braking
Go to direction closing valve the cut valve by the one end
Operation is allowed Rutotomoni, the expander piston to vary the volume of the output hydraulic pressure chamber, an eccentric member which connects the other end of the expander piston
Which should move the expander piston forward and backward.
Rotating the expander piston to the input hydraulic chamber side.
A coil spring that presses and biases the eccentric member , wherein the coil spring has a retracting direction of the expander.
90 with respect to the direction of movement of the piston toward the input hydraulic chamber.
A modulator for an anti-lock brake, characterized in that the angle is set to satisfy θ <θs <180 ° . Wherein an input pressure chamber communicating with the master cylinder, an output hydraulic chamber which communicates with the wheel brake, the communication passage which communicates the input hydraulic chamber and the output hydraulic chamber
And moving to the input hydraulic chamber side to
Opening the passage and moving to the output hydraulic chamber side
A cut valve for shutting off the communication passage, and an output hydraulic pressure
Constitutes a chamber, and normally moves to the input hydraulic chamber side during braking.
While operating the valve opening of the cut valve by the one end,
Those who are separated from the input hydraulic chamber side during antilock braking
Go to direction closing valve the cut valve by the one end
Operation is allowed Rutotomoni, the expander piston to vary the volume of the output hydraulic pressure chamber, an eccentric member which connects the other end of the expander piston
Which should move the expander piston forward and backward.
Rotating the expander piston to the input hydraulic chamber side.
A coil spring that presses and biases the eccentric member ;
Start of rotation of the eccentric member at the time of switching to back braking
And a regulating member for regulating the angle, the regulating member, the input of the expander piston
The rotation axis of the crank with respect to the moving direction to the hydraulic chamber side
The rotation start angle θp of the line from the eccentric member to the eccentric member is 0 ° <
Modulators antilock brakes, characterized that you regulations θp ≦ 90 °.