JPH03109154A - Modulator for antilock brake - Google Patents

Abstract

PURPOSE:To reduce the dimension of the device and reduce the necessary number of parts by revolving a driving shaft by a motor and shifting an expander piston by shifting an eccentric part towards a bottom dead center and closing a cut valve. CONSTITUTION:A modulator M which is interposed midway in a brake pipe which connects the master cylinder of a motorcycle and a wheel brake is equipped with an input hydraulic chamber 16 which communicates to a master cylinder, output hydraulic chamber 21 which communicates to a wheel brake, and a cut valve 17 which communicates to and cuts off the part between the both hydraulic chambers 16 and 21. Further, an expander piston 20 which opens the but valve 17 in the ordinary brake application and closes the valve in the antilock control operation is provided. In this case, a driving shaft 25 which has an eccentric part 28 contacting the back surface of the piston 20 and is driven by a motor 12 is provided. In the ordinary brake application, the piston 20 is restrained by positioning the eccentric part 28 at a top dead center, and the cut valve 17 is kept in opened state.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (1) Industrial Field of Application The present invention relates to a modulator for controlling brake hydraulic pressure transmitted from a master cylinder to wheel brakes in an anti-lock brake system for a vehicle.

(2) Prior Art Usually, a modulator for an anti-lock brake system for a vehicle includes a cut valve that controls communication/cutoff between an input hydraulic chamber communicating with a master cylinder and an output hydraulic chamber communicating with wheel brakes, and The expander piston is disposed in the hydraulic chamber and closes the cut pulp when the anti-lock brake control system is activated, and also increases the volume of the output hydraulic chamber to reduce the brake hydraulic pressure.

Conventionally, in such an anti-lock brake device, control oil pressure generated by a hydraulic pump is supplied to a modulator via a solenoid valve, and the expander piston is actuated by the oil pressure.

(3) Problems to be Solved by the Invention However, in the above-mentioned conventional anti-lock brake device, the control hydraulic pressure supplied to the modulator is controlled by a solenoid valve to operate the expander piston, so a hydraulic circuit for this purpose is required. As a result, the number of parts increased, and special techniques and man-hours were required not only for productivity but also for maintenance and inspection.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a modulator for anti-lock brakes that does not require a control hydraulic circuit with a large number of parts and has excellent inspection and maintenance performance and responsiveness. .

B1 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides an input hydraulic chamber communicating with the master cylinder, an output hydraulic chamber communicating with the wheel brakes, and a hydraulic pressure chamber in both sleeves. A cut pulp that connects and blocks communication between the chambers, and a cut pulp that is arranged to face the output hydraulic pressure chamber, opens the cut pulp during normal braking, closes the cut pulp when anti-lock control is activated, and changes the output hydraulic pressure. An anti-lock brake modulator including an expander piston that increases the volume of a chamber, including a drive shaft having an eccentric portion that comes into contact with the back surface of the expander piston, and a drive shaft that rotates to move the expander piston. An electric motor is provided, and the expander piston is restrained by positioning the eccentric portion at the top dead center during normal braking.

(2) Function According to the feature of the present invention described above, during normal braking, the eccentric portion provided on the drive shaft is located at the top dead center and restrains the expander piston, so that the cut pulp is forced to open. The master cylinder and wheel brake communicate with each other. At this time, the brake hydraulic pressure generated in the master cylinder is transmitted to the eccentric part via the expander piston, but since this eccentric part is located at the top dead center, no load is applied to the electric motor. .

When the anti-lock control is activated, the electric motor rotates the drive shaft, and its eccentric portion moves toward the bottom dead center. As a result, the expander piston moves and the cut pulp valve closes, and at the same time, the volume of the output hydraulic pressure chamber increases, the brake hydraulic pressure decreases, and the wheels are prevented from entering a locked state.

(3) Examples Hereinafter, the present invention will be explained in detail based on the drawings.

Figures 1 to 7 show a first embodiment of the present invention. Figure 2 is an overall side view of a motorcycle equipped with the modulator, Figure 2 is an enlarged view of the 3 is a sectional view taken along the line ■-■ in FIG. 2, FIG. 4 is a sectional view taken along the TV-TV line in FIG.
A line sectional view, Figure 6 is a line sectional view taken along the line Vl-Vl in Figure 4, and Figure 7
The figure is a sectional view taken along the line ■--■ in FIG. 4.

As shown in Figure 1, the front wheel brake of motorcycle V is
The vehicle is equipped with a master cylinder Cm driven by a brake lever 2 provided on a handle 1 and a caliper cylinder Cc for braking the front wheel Wf, and the master cylinder Cm and caliper cylinder Cc are attached to the front part of a front fork 3. They are interconnected via a modulator M. On the other hand, the rear wheel brake is operated by a master cylinder Cm driven by a brake pedal 4 provided at the rear lower part of the vehicle body and a rear wheel Wr.
The motor is equipped with a caliper cylinder Cc for braking, and a modulator M disposed between the master cylinder Cm and the caliper cylinder Cc. The modulators M for the rear wheel Wr and the front wheel Wf have the same structure, and the modulator M for the front wheel Wf will be described below.

As shown in FIGS. 2 and 3, a top bridge 6 and a bottom bridge 7 that support left and right front forks 3 are pivotally supported on the head pipe 5 of the motorcycle (2).

In the upper front space of the bottom bridge 7, there is a roughly cylindrical modulator M whose both ends are connected to the left and right front forks 3.
A mounting plate 8 is disposed in a horizontal position so as not to protrude outward from the bottom bridge 7 and has an elastic material wrapped around its outer circumference to prevent the transmission of operating noise and vibrations to the handle l, and is fastened to the bottom bridge 7 with bolts 9. It is installed by By attaching the modulator M as described above, the modulator M is protected by being surrounded by the left and right front forks 3 and the bottom bridge 7, and is also prevented from interfering with tires or fenders during steering. In addition, by locating the modulator M near the head pipe 5, which is the center of rotation, not only can the twisting of the piping during steering be minimized, but also the modulator M is located close to the head pipe 5, which is the center of rotation.
By locating it approximately midway between the caliper cylinder Cc and the caliper cylinder Cc, the length of the piping can be shortened.

As shown in FIGS. 4 and 5, the modulator M consists of a main body storage part 10 and a driving DC motor 12 connected to one end of the main body storage part 10 with a bolt 11.
An input hydraulic chamber 16 connected to the master cylinder Cm via a manual boat 15 is formed in the valve housing section 14 connected to the side surface of the cylinder O through ports 1-13, and a cut valve 17 is housed inside the valve housing section 14. ing. The cut valve 17 is composed of a shaft portion 17a that fits loosely into a communication hole 14a formed in the end wall of the valve storage portion 14, and a valve body 17b that can come into contact with a valve seat 14b formed in the end wall. Valve body 17
b is biased in the valve closing direction by a spring 19 compressed between the spring seat 18; and a cylindrical output hydraulic chamber 21 into which the expander piston 20 is slidably fitted; is formed, and this output hydraulic chamber 2
1 communicates with the caliper cylinder Cc via the output port 22, and communicates with the input hydraulic chamber 16 via the communication hole 14a.

A drive shaft 25 is rotatably supported in a space formed inside the main body housing part 10 via a pair of ball bearings 23 and 24. The drive shaft 25 is composed of two members: a first drive shaft 26 having an internal gear 26a and an eccentric hole 26b, and a second drive shaft 27 having an eccentric pin 27a that fits into the eccentric hole 26b. A cam bearing 28 as an eccentric part that comes into contact with the back of the expander piston 20 is mounted on the bin 27a. When the cam bearing 28 attached to the drive shaft 25 is at the top dead center, the top surface of the expander piston 20 is at the cut valve 1.
The cut pulp 17 is opened by pushing up the shaft portion 17a of the cylinder 7, and the master cylinder Cm and the caliper cylinder Cc are brought into communication with each other.

As is clear from FIG. 6, a pinion 29a is formed at the tip of the output shaft 29 of the DC motor 12.
meshes with an internal gear 26a formed on the first drive shaft 26 to rotationally drive the drive shaft 25.

By using the internal gear 26a in this manner, the drive shaft 25 and the DC motor 12 are disposed substantially coaxially, making it possible to minimize the outer diameter of the modulator M. A stopper piece 26c is protruded from the outside of the internal gear 26a, and by bringing this stopper piece 26a into contact with the regulating surfaces 10a and 10b formed on the inner surface of the main body storage portion 10,
The rotation angle of the drive shaft 25 is restricted to a range of about 180°.

As is clear from FIG. 7, a return spring 30 is installed between the end of the second drive shaft 27 and the main housing 10, and its elastic force causes the drive shaft to
5 is biased by the cam bearing 28 in the direction toward the top dead center, that is, in the direction in which the cut pulp 17 opens.

A potentiometer 31 is attached to the opposite end of the DC motor 12 of the main body housing 10, and its input shaft 31
a is connected to the end of the second drive shaft 27 by a pin 32 and rotates in the same phase. The signal from the wheel speed sensor 34 and the feedback signal from the potentiometer 31 are inputted to an electronic control unit 33 made up of a microcomputer and are subjected to arithmetic processing, and the drive of the DC motor 12 is controlled based on the results.

Next, the operation of the embodiment of the present invention having the above-described configuration will be explained.

During normal braking, the stopper piece 26c of the drive shaft 25 comes into contact with the regulating surface 10a formed on the inner surface of the main body housing part 10 due to the elastic force of the return spring 30, and the cam bearing supported on the eccentric pin 27a of the drive shaft 25 28 is held at the top dead center and pushes up the expander piston 20. This causes the cut valve 17 to
The brake hydraulic pressure generated in the master cylinder Cm is forcibly opened against the pressure 9, and the brake hydraulic pressure generated in the master cylinder Cm is transferred to the caliper cylinder via the input cylinder 15, the input hydraulic pressure chamber 16, the communication hole 14a, the output hydraulic chamber 21, and the output boat 22. Conveyed to CC. At this time, the brake hydraulic pressure in the output hydraulic chamber 21 acts to push down the expander piston 20, but since the cam bearing 28 that contacts the back surface of the expander piston 20 is located at the top dead center, the drive shaft 25 Rotational torque is not generated by the brake oil pressure, and as a result, unnecessary load is prevented from being applied to the DC motor 12 connected to the drive shaft 25.

When the wheel speed sensor 34 detects that the front wheel Wf is about to enter the locked state, the electronic control device 33
The DC motor 12 is driven, and its rotation is transmitted to the drive shaft 25 via the pinion 29a and the internal gear 26a. The drive shaft 25 starts rotating and the cam bearing 2
8 moves from top dead center, the expander piston 20
Since the brake oil pressure acting on the cam is added to the torque of the DC motor 12, the expander piston 20 presses the cam bearing 28 and quickly descends. As a result, the cut valve 17 separated from the expander piston 20 closes due to the elastic force of the spring 19, and the volume of the output hydraulic chamber 21 increases, causing the caliper cylinder C to close.
The brake hydraulic pressure transmitted to c decreases.

When the front wheel Wr is prevented from entering the locked state, the power supply to the DC motor 12 is stopped, the drive shaft 25 returns to its original position by the elastic force of the return spring 30, and the brake oil pressure increases again. In this way, the DC motor 12
By repeatedly starting and stopping the brake, the brake oil pressure is controlled and the front wheel Wf is prevented from entering a locked state. At this time, the rotational position of the drive shaft 25 detected by the potentiometer 31 corresponds to the amount of movement of the expander piston 20, that is, the magnitude of the brake oil pressure transmitted to the caliper cylinder Cc, and this signal is transmitted to the electronic control device 34. For example, the DC motor 12 is driven in a direction that supports the elastic force of the return spring 30, or a direction in which the force is reduced. It is also possible to make the most of the advantages of a closed loop configuration by applying the brakes to the

8 and 9 show a second embodiment of the present invention, in which FIG. 8 is a circuit diagram of an anti-lock brake device using the modulator, and FIG. 9 is a longitudinal sectional view of the modulator.

As shown in FIG. 8, in this embodiment, the rear wheel Wr is equipped with one caliper cylinder Cc, the front wheel Wf is equipped with two caliper cylinders Cc, and the modulator M on the rear wheel Wr side
is the same as that of the previous embodiment, but the modulator M' on the front wheel Wf side is of a tandem type. A master cylinder Cm operated by the brake pedal 4 is connected to the modulator M on the rear wheel Wr side via a pressure control valve 35, and a master cylinder Cm operated by the brake pedal 4 is connected to the modulator M' on the front wheel Wf side. is connected via the pressure control valve 35 and the brake lever 2
A master cylinder Cm operated by the cylinder is connected to the cylinder.

As shown in FIG. 9, the tandem type modulator M' is provided with a pair of input ports 15 and an output port 22 to correspond to a pair of caliper cylinders Cc mounted on the front wheels Wr. Respective input ports 15 and output ports 22
There are also a pair of cut valves 17 and expander pistons 20 interposed between them to control the brake oil pressure, and a pair of cam bearings 28 that come into contact with each expander piston 20 are also extended from the drive shaft 25. It is also provided on the eccentric pin 27a.

According to the modulator M' of this embodiment, it is possible to obtain the same effects as the modulator M of the previous embodiment, and furthermore, the master cylinder Cm operated by the brake lever 2 and the master cylinder Cm operated by the brake pedal 4 are Even if either one of the cylinders Cm fails, the braking force for the front wheels Wf is ensured.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and may be modified without departing from the scope of the invention described in the claims. It is possible to do this.

For example, it is possible to use other electric motors such as an AC motor or a step motor in place of the DC motor. Moreover, it is possible to replace the potentiometer 31 with another suitable encoder.

C0 Effects of the Invention As described above, according to the present invention, since the modulator is driven by an electric motor, the control hydraulic system including the hydraulic pump and solenoid valve required by the conventional hydraulically driven modulator can be omitted. As a result, it becomes possible to downsize the device and reduce the number of parts. Further, since the eccentric portion provided on the drive shaft restrains the expander piston at the top dead center during normal braking, unnecessary load is prevented from being applied to the electric motor by the brake hydraulic pressure. Furthermore, when the drive shaft begins to rotate during anti-lock control operation, the brake oil pressure acts in a direction that assists the rotation of the drive shaft, so when the brake oil pressure is large, it is possible to obtain rapid pressure reduction response characteristics. Become.

[Brief explanation of drawings]

1 to 7 show a first embodiment of the present invention. FIG. 1 is an overall side view of a motorcycle equipped with the modulator, FIG. 2 is an enlarged view of the 3 is a sectional view taken along the line ■-■ in FIG. 2, FIG. 4 is a sectional view taken along the IV-IV line in FIG. 3 showing the longitudinal section of the modulator, and FIG.
A line sectional view, Figure 6 is a line sectional view taken along the line Vl-Vl in Figure 4, and Figure 7
The figure is a sectional view taken along the line ■-■ in FIG. 4, FIGS. 8 and 9 show a second embodiment of the present invention, and FIG. 8 is a circuit diagram of an anti-lock brake device using the modulator. 9th
The figure is a longitudinal sectional view of the modulator. 12... DC motor (electric motor), 16... Human hydraulic pressure chamber, 17... Cut pulp, 20... Expander piston, 21... Output hydraulic chamber, 25... Drive shaft, 28 ...Cam bearing (eccentric part), Cm...
master cylinder

Claims (1)

[Claims] Input hydraulic chamber (16) communicating with master cylinder (Cm)
, an output hydraulic chamber (21) that communicates with the wheel brakes, a cut valve (17) that communicates/cuts off communication between the two hydraulic chambers (16, 21), and an output hydraulic chamber (21) arranged to face the output hydraulic chamber (21). The cut valve (17) is provided during normal braking.
An anti-lock brake modulator comprising an expander piston (20) that opens the cut valve (17) and increases the volume of the output hydraulic chamber when the anti-lock control is activated. A drive shaft (25) having an eccentric portion (28) that comes into contact with the back surface of the (20), and an electric motor (12) that rotates the drive shaft (25) to move the expander piston (20), During normal braking, the eccentric portion (28
) at top dead center, and then remove the expander piston (20).
A modulator for anti-lock brakes that is characterized by restraining.