JPH05105051A - Modulator for antilock brake - Google Patents

Abstract

PURPOSE:To provide a modulator for an antilock brake with a reduction mechanism which is able to promote an improvement in a response at the time of changeover to an antilock control operation and the miniaturization of a driving source at the same time. CONSTITUTION:An antilock braking modulator has a reduction mechanism 44 which is provided with a small diametral drive gear 60 engaging with a driving shaft 22a of an electric motor 22, a large diametral driven gear 62 engaging with this driving gear 60, a gear holding member 66 holding this driven gear 62 on a body part 21 via ball bearings 64a, 64b, a plate spring 68 for making the driven gear 62 slidingly contact with the gear holding member 66, an eccentric pin 70 being installed eccentrically as far as the specified value to the rotational center of the gear holding member 66, a crank eccentric pin 41 being installed on an axis of an eccentric part 40a of a crank member 40 and a link member 72 connecting these eccentric pins 70, 41 rotatably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antilock brake modulator, and more specifically, to improve response at the time of switching to antilock control and to downsize an electric motor as a drive source. It relates to a modulator for an antilock brake having a possible deceleration structure.

[0002]

2. Description of the Related Art Some brake devices, which are means for stopping and decelerating a vehicle such as a motorcycle, have an antilock control mechanism.

For example, in a two-wheeled vehicle, a disc type brake device having an antilock control mechanism includes a master cylinder for converting a brake operation command generated by a driver's lever operation and a petal operation into hydraulic pressure, and a brake disk. By interposing in the brake operation command transmission path from the master cylinder to the caliper cylinder that a braking force is generated by being sandwiched by calipers based on the oil pressure, the anti-lock control operation is performed by adjusting the oil pressure. It is composed of a modulator and an executing modulator.

As shown in FIG. 5, a modulator 1 that substantially performs an antilock control operation by adjusting hydraulic pressure includes an input hydraulic chamber 2 that communicates with a master cylinder.
An output hydraulic chamber 4 that communicates with a caliper cylinder that brakes the wheels, a cut valve 6 that connects and disconnects the input hydraulic chamber 2 and the output hydraulic chamber 4, and an anti-lock provided on the output hydraulic chamber 4 side. An expander piston 8 is provided which closes the cut valve 6 during control operation and increases the volume of the output hydraulic chamber 4 to reduce the hydraulic pressure.

In the anti-lock control mechanism, an electric motor 10 is used as a drive source for opening and closing the cut valve 6 and operating the expander piston 8 for changing the volume of the output hydraulic chamber 4. When converting the driving force of the electric motor 10, the driving force is applied to the crank member 12 via a reduction mechanism including a drive gear 14 attached to the drive shaft 10 a of the electric motor 10 and a driven gear 9 attached to the crank member 12. Is transmitted to shift the eccentric portion 12a, which comes into contact with the surface portion 8a of the expander piston 8 via the bearing 11. As a result, the expander piston 8 is displaced, and the cut valve 6 is opened / closed and the volume of the output hydraulic chamber 4 is increased / decreased.

[0006]

In order to perform the displacement of the expander piston 8, the crank member 12 which is in contact with the surface portion 8a of the expander piston 8 via the eccentric portion 12a is rotated. It is necessary to generate torque as much as possible. In this case, in order to secure the torque required to rotate the crank member 12 and achieve the size reduction of the electric motor 10, the reduction ratio from the electric motor 10 to the crank member 12 is set to be sufficiently large. There is a need to.

On the other hand, in the above configuration, the driving force of the electric motor 10 is set to the maximum required torque. Therefore, when the electric motor 10 is downsized and the reduction gear ratio is set to a large value, the electric power of the driving source is set. The crank rotation speed (rotation angle) with respect to the motor rotation speed (rotation angle) of the motor 10 becomes small, and as a result, the motor rotation angle for obtaining the crank rotation angle required to close the cut valve 6 becomes smaller. As a result, the inconvenience that the response at the time of switching the antilock control operation is deteriorated is exposed.

Therefore, in order to overcome the above-mentioned inconvenience, the present invention provides an antilock brake modulator capable of simultaneously improving the response at the time of switching to the antilock control operation and downsizing the drive source. With the goal.

[0009]

In order to solve the above problems, the present invention provides an input hydraulic chamber communicating with a master cylinder, an output hydraulic chamber communicating with a wheel brake, the input hydraulic chamber and the output hydraulic chamber. And a cut valve for connecting and disconnecting the valve and the output hydraulic chamber side, the cut valve is opened by one end during normal braking, and the cut valve is closed by the one end during antilock braking operation. An expander piston that increases the volume of the output hydraulic chamber, a crank member that has an eccentric portion that contacts the other end of the expander piston, and the expander piston is displaced by rotating the crank member. A drive source, a first eccentric pin provided eccentric with respect to a rotation center on the drive source side by a predetermined distance, and a rotation center of the crank member. And having a connecting member for connecting a second eccentric pin which is provided with a predetermined distance eccentrically, and said second eccentric pin and the first eccentric pin against.

[0010]

In the modulator for an antilock brake according to the present invention, the driving force generated by the driving source is transmitted to the crank member via the first eccentric pin, the connecting member and the second eccentric pin, and the crank member is rotated. The expander piston is displaced by the movement. In this case, the reduction ratio of the driving force transmission mechanism changes according to the rotation angle. Therefore,
By adjusting the deviation amounts of the first and second eccentric pins, the reduction ratio for closing and opening the cut valve can be reduced, and the reduction ratio for increasing or decreasing the volume of the output hydraulic chamber can be set large. it can.

[0011]

The preferred embodiments of the modulator for an antilock brake according to the present invention will be described below in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 20 indicates a modulator according to the embodiment. The modulator 20 basically comprises a main body 21, an electric motor 22, and a potentiometer 24.

The main body portion 21 has an input hydraulic chamber 28 which communicates with a master cylinder (not shown) through an input port 26,
An output hydraulic chamber 32 that communicates with a wheel brake via an output port 30, a cut valve 34 that connects and disconnects the input hydraulic chamber 28 and the output hydraulic chamber 32, an opening and closing of the cut valve 34, and the output hydraulic chamber 32. Of the expander piston 36 whose upper surface portion 36a contacts the cut valve 34, the crank member 40 having an eccentric portion 40a which contacts the lower surface portion 36b of the expander piston 36, and a drive source. The electric motor 22 and the motor torque generated by the electric motor 22 are transferred to the crank member 4
And a deceleration mechanism 44 for transmitting to zero.

The cut valve 34 is provided in the input hydraulic chamber 28.
A valve seat 34a having a flange portion, which is arranged so as to surround the communication hole 46 which communicates the output hydraulic chamber 32 with the output hydraulic chamber 32, and is loosely fitted in the communication hole 46 so as to come into contact with the flange portion of the valve seat 34a. And a valve element 34b that shuts off the communication state. A spring member 50 supported by a guide rod 50a is contracted between the cut valve 34 and the wall surface of the input hydraulic chamber 28 facing the cut valve 34. Therefore, the valve body 3
4b is urged in the valve closing direction by the elastic force of the spring member 50, and the upper surface portion 36 of the expander piston 36 is constantly maintained.
It is in contact with a.

In the expander piston 36, the lower surface portion 36b located on the opposite side of the upper surface portion 36a is
It is in contact with the eccentric portion 40a of the crank member 40.

A backup spring 52 is in contact with the eccentric portion 40a of the crank member 40 on the opposite side of the expander piston 36 via a roller portion 40b. As a result, when the antilock brake system (ABS) is not in operation, the crank member 40 is always disposed at the top dead center due to the elastic force of the backup spring 52. Therefore, the valve body 34b of the cut valve 34 that is in contact with the crank member 40 and is biased in the valve closing direction by the elastic force of the spring member 50 is held in the valve open state.

A potentiometer 24 is mounted on the main body 21 with an electric motor 22 interposed therebetween. The input shaft 56 of the potentiometer 24 is connected to the end of the crank member 40 and rotates in the same phase. The modulator 20
Is controlled by a phase signal emitted from the potentiometer 24 and a state detection signal based on the wheel speed of the wheel.

Next, the speed reducing mechanism 44 for converting the motor torque generated by the electric motor 22 as a drive source into the torque required for the eccentric portion 40a to rotate and transmitting it to the crank member 40 will be described. ..

The reduction mechanism 44 has a small-diameter drive gear 60 that engages with the drive shaft 22a of the electric motor 22, and a large-diameter driven gear 62 that engages with the drive gear 60.
And a gear holding member 66 for holding the driven gear 62 on the main body 21 via ball bearings 64a and 64b.
A leaf spring member 68 for slidingly contacting the driven gear 62 with the gear holding member 66, and an eccentric pin 70 eccentric with respect to the rotation center axis of the gear holding member 66 by a predetermined amount.
A crank eccentric pin 41 provided on the axis of the eccentric portion 40a of the crank member 40, and these eccentric pins 70,
And a link member 72 that rotatably connects 41.

The antilock brake modulator 20 according to the present invention is basically constructed as described above. Next, the operation and effect of the modulator 20 will be described.

In the normal braking state, the crank member 4
The eccentric portion 40a of 0 is pushed up by the backup spring 52 and is held at the top dead center.

Therefore, the cut valve 34 which is interlocked with the crank member 40 through the expander piston 36 is
The flange portion of the valve seat 34a is disengaged against the elastic force of the spring member 50 and pushed up in the communication hole 46 to connect the input hydraulic chamber 28 and the output hydraulic chamber 32.

At this time, the hydraulic pressure generated by the driver's lever operation or pedal operation via the master cylinder is applied to the input port 26, the input hydraulic chamber 28, the communication hole 46, and the output hydraulic chamber 3
2, transmitted to the caliper cylinder through the brake transmission path formed of the output port 30 to perform normal brake braking.

In the modulator 20,
The hydraulic pressure acts to push down the expander piston 36, but since the expander piston 36 is held at the top dead center by the backup spring 52 via the crank member 40, the speed reducing mechanism 44 is attached to the crank member 40. In the drive unit 42a connected via the electric motor 2, a rotational torque due to the hydraulic pressure is not generated and an unnecessary load is applied to the electric motor 2.
It is never given to 2.

On the other hand, when the wheel speed sensor arranged on the wheel detects a sudden deceleration of the wheel, a detection signal is input to the electronic control unit, and the electronic control unit controls the drive shaft 22a of the electric motor 22. Driving is started.

The drive force of the drive shaft 22a is transmitted to the crank member 40 by the reduction mechanism 44, and the crank member 40 is rotated at a suitable speed. The crank member 4
When the eccentric portion 40a leaves the holding state at the top dead center with the rotation of 0, the hydraulic pressure acting to push down the expander piston 36 imparts a rotational torque to the drive shaft 22a of the electric motor 22. Therefore, the crank member 40
When the rotation of the expander piston 36 is started, the expander piston 36 is displaced by the hydraulic pressure in the contact direction with the crank member 40, and at the same time, the lower surface part 38b of the expander viston 36 is moved.
The eccentric portion 40a of the crank member 40, which abuts at, is displaced toward the bottom dead center.

As a result, the valve element 34b of the cut valve 34 that abuts the upper surface portion 36a of the expander piston 36.
Is closed by contacting the flange portion of the valve seat 34a by displacing in the communication hole 46 by the elastic force of the spring member 50, and disconnecting the communication state between the input hydraulic chamber 28 and the output hydraulic chamber 32. To do.

Further, with the displacement of the expander piston 36, the volume of the output hydraulic chamber 32 whose one wall surface is defined by the upper surface portion 36a increases. As a result, the hydraulic pressure of the brake oil interposed between the caliper cylinder and the caliper cylinder is reduced, and the braking force is reduced in the brake device controlled by the hydraulic pressure transmitted to the caliper cylinder.

As a result of the above, when the electronic control unit detects from the detection signal from the wheel speed sensor arranged on the wheel that the wheel has suddenly decelerated, the electronic control unit sends the electric motor 22 a signal. The current value is adjusted, driving of the drive shaft 42a is stopped or rotated in the opposite direction, and the brake fluid pressure is suitably controlled.

By repeating the rotation and stop of the electric motor 22 as described above, the hydraulic pressure of the brake oil is controlled and the antilock control is activated.

The potentiometer 24 detects the rotational position of the crank member 40, whereby the displacement amount of the expander piston 36, that is, the hydraulic pressure of the brake oil transmitted to the caliper cylinder is detected. Therefore, antilock control can be performed by detecting the displacement amount from the top dead center to the bottom dead center of the expander piston 36 and inputting it to the electronic control unit.

Here, in the speed reduction mechanism 44 of the present embodiment, the response is improved and the electric motor 22 is downsized by changing the speed reduction ratio. That is, as shown in FIGS. 1 to 3, the parameters are: e ₁ : the distance from the rotation center axis O ₁ of the gear holding member 66 to the rotation center axis P ₁ of the eccentric pin 70 e ₂ : the rotation center axis of the crank member 40 O ₂ to eccentric part 4
0a to the rotation center axis P ₂ θ ₁ : rotation angle of the gear holding member 66 θ ₂ : rotation angle of the eccentric portion 40a with respect to θ ₁ R: rotation center axis P ₁ of the eccentric pin 70 and the eccentric portion 40a Distance between the rotation center axis P ₂ and the rotation center axis P ₂ : The rotation center axis O ₁ of the gear holding member 66 is defined as a distance eccentric to the rotation center axis O ₂ of the crank member 40. The rotation angle β of the member 40 and the rotation angle α of the rotation body 58a
The relationship with is expressed by the following mathematical formula.

[0033]

[Equation 1]

However,

[0035]

[Equation 2]

It is

Further, each alpha ₀ the initial position of the crank member 40, if beta _0, the rotational angle theta ₁ of the crank member 40, the relationship between theta _2, given by the following equation.

[0038]

[Equation 3]

[0039] FIG. 4 is a graph showing an example of the rotation angle theta ₂ of the relationship between the eccentric portion 40a relative to the rotational angle theta ₁ of the gear holding member 66 derived from equation (3). In addition, when the crank member 40 is at the uppermost stage, θ ₁ = 0 deg (θ ₂ = 0d
Eg). The graph shows e ₁ : gear holding member 66
Of 6mm the distance to the rotational center P ₁ of the rotation center axis O ₁ of the eccentric pin 70, e _2: the distance from the rotation center axis O ₂ of the crank member 40 to the rotational center axis P ₂ of the eccentric portion 40a 5
mm, α ₀ : The initial position of the gear holding member 66 is 80 de
g, β ₀ : The initial position of the crank member 40 is 200 de
g, l: Calculated by setting the rotation center O ₁ of the gear holding member 66 to be the amount of deviation made with respect to the rotation center axis O ₂ of the crank member 40.

In the graph, the eccentric portion 40a of the crank member 40 starts to rotate on the basis of the straight line A having the inclination of 1, and the angle from the start of the cut valve 34 until θ ₂ reaches about 26 deg is increased. It is accelerated and θ ₂ is 60 deg.
From the above, it is easily understood that the vehicle is decelerated.

Therefore, the eccentric portion 40a of the crank member 40
The torque is set small and the reduction gear ratio is set small in the range from the start of rotation to the operation of the cut valve 34 where θ ₂ reaches about 26 deg. Therefore, the expander piston 36 is displaced at high speed. Therefore, the response at the time of switching the antilock control can be improved. When θ ₂ is 60 deg or more, the required torque increases, but the reduction ratio is set to a large value, so that the driving force of the electric motor 22 can be small.
Can be miniaturized.

In the deceleration mechanism 44, the rotation center axis of the drive shaft 22a of the electric motor 22 and the rotation center axis O of the rotation member 58 are not provided via the drive gear 60 as a means for transmitting the driving force of the electric motor 22. It is also possible to join directly so that the ₁ 's match.

[0043]

As described above, in the antilock brake modulator according to the present invention, the reduction ratio can be changed in accordance with the displacement of the crank position. That is, in the range in which the expander piston opens and closes the cut valve, the reduction ratio can be reduced to displace the expander piston at high speed, which can improve the control response. Further, with respect to the range in which the volume is increased or decreased by the expander piston, the reduction gear ratio can be increased, which allows the drive source to have a small torque.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a preferred embodiment of an antilock brake modulator according to the present invention.

FIG. 2 is a conceptual diagram showing a joined state of link members of the modulator for an antilock brake according to the present invention.

FIG. 3 is a conceptual diagram illustrating a reduction mechanism of an antilock brake modulator according to the present invention as a lever crank mechanism.

FIG. 4 is a graph showing a relationship between a rotation angle of an eccentric portion of a crank member and a rotation angle of a gear holding member in a preferred embodiment of the anti-lock brake modulator according to the present invention.

FIG. 5 is a vertical cross-sectional view of a conventional anti-lock brake modulator.

[Explanation of reference numerals] 20 ... Modulator 22 ... Electric motor 28 ... Input hydraulic chamber 32 ... Output hydraulic chamber 34 ... Cut valve 36 ... Expander piston 40 ... Crank member 40a ... Eccentric portion 41 ... Crank eccentric pin 44 ... Reduction mechanism 66 ... Gear holding member 70 ... Eccentric pin 72 ... Link member

Claims (1)

[Claims] 1. An input hydraulic chamber communicating with a master cylinder, an output hydraulic chamber communicating with a wheel brake, a cut valve connecting and disconnecting the input hydraulic chamber and the output hydraulic chamber, and an output hydraulic chamber arranged on the output hydraulic chamber side. An expander piston that is provided and that opens the cut valve by one end during normal braking and closes the cut valve by the one end during antilock braking operation and increases the volume of the output hydraulic chamber; A crank member having an eccentric portion that comes into contact with the other end of the expander piston, a drive source that displaces the expander piston by rotating the crank member, and a predetermined rotation center on the drive source side. A first eccentric pin eccentrically provided with a distance, and a second eccentric pin eccentrically provided with a predetermined distance with respect to a rotation center of the crank member. And a connecting member that connects the first eccentric pin and the second eccentric pin, and a modulator for an antilock brake, comprising: