JPH0687424A - Anti-lock braking device - Google Patents

Abstract

PURPOSE:To efficiently and stably operate an anti-lock braking device, by providing a control means, closing an electromagnetic cut valve when a wheel is locked based on the detection signals of the hydraulic sensor of a hydraulic circuit and a braking torque sensor; and an elastic member dislocating a brake caliper and a feed back piston according to braking torque. CONSTITUTION:A brake caliper 2 is connected to a master cylinder 5 via an electromagnetic cut valve 7 for opening and closing a hydraulic circuit 6. When the detection signal of a brake switch 20 is turned ON, or the detected value of a hydraulic sensor 9 exceeds a given value and that of a braking torque sensor 10 is less than the given value; the electromagnetic cut valve 7 is electrified by a control device 11, and the hydraulic oil between the master cylinder 5 and the brake caliper 2 is switched to a position (b), where the hydraulic oil is shut off by a check valve 49, preventing a locked condition. The free end of a platelike supporting spring 4 is dislocated in a vertical direction following the increase/decrease of braking torque. Consequently hydraulic pressure, controlled by a feed back piston 8, can be set to a proper value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antilock brake device for a motorcycle or the like which prevents the wheels from being locked during braking.

[0002]

2. Description of the Related Art If the rotation of wheels is locked during braking of a two-wheeled vehicle, the wheels will slip or skid on the road surface. Therefore, the braking torque is controlled so that the rotation of the wheels is not completely locked during braking operation. As a brake device equipped with an anti-lock mechanism
No. 5 publication is known.

[0003]

The above-described anti-lock brake device increases or decreases the braking hydraulic pressure by the position detecting rod that is displaced by receiving the reaction force of the braking torque and the pressure responsive member that responds to the braking hydraulic pressure, and responds to the road surface condition. This is for mechanically controlling the optimum braking torque, and a spring in which a plurality of disc springs and flat washers are superposed is used as a spring for supporting the braking torque.

When the support spring is displaced by a load, slip occurs at the contact portion between the disc spring and the flat washer, and the relationship between the load and the displacement applied to the disc spring draws a hysteresis loop as shown in FIG. For this reason, the hydraulic pressure of the brake controlled by the position detection rod may differ between the contracting side and the expanding side, which may reduce the performance and efficiency of the antilock function. Therefore, the present invention has been made focusing on the above problems,
An object is to provide an antilock brake device that operates efficiently and stably.

[0005]

SUMMARY OF THE INVENTION The present invention includes an electromagnetic cut valve for opening and closing a hydraulic circuit connecting a master cylinder and a brake caliper, and a feedback piston which also changes the volume of the hydraulic circuit according to the displacement of the brake caliper.
A hydraulic sensor for detecting the hydraulic pressure guided to the brake caliper, a braking torque sensor for detecting the braking torque applied by the brake caliper, and a control means for closing the electromagnetic cut valve when the wheels are locked based on these detection signals. The base end is fixed to the vehicle body side, and the elastic member supports the brake caliper and the feedback piston on the free end side so as to be displaceable according to the braking torque.

A displacement amount adjusting means for regulating the displacement amount of the elastic member is provided.

[0007]

Therefore, in an operating state where the wheels are likely to lock, the control means closes the electromagnetic cut valve, and the feedback piston expands the volume of the hydraulic circuit to the brake caliper due to the reduction of the braking torque and the elastic restoring force of the support spring. Temporarily reduce the hydraulic pressure introduced to avoid locking the wheels.

While fixing the base end of the elastic member to the vehicle body side,
Since the brake caliper and the feedback piston are supported on the free end side, the displacement due to the contraction and extension of the feedback piston and the displacement of the elastic member become equal, so that the hydraulic pressure can be accurately controlled.

Since the amount of displacement of the elastic member can be adjusted, the antilock effect can be exerted in a wide range.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the brake caliper 2 is displaceably fixed by a link 3 having one end connected to a free end of a support spring 4 fixed to the front fork 22 side, and the brake caliper 2 opens and closes a hydraulic circuit 6. It is connected to the master cylinder 5 via the electromagnetic cut valve 7. A cylinder body 26 for accommodating a feedback piston 8 that changes the volume of the hydraulic circuit 6 is attached to the free end of the link 3.

A hydraulic pressure sensor 9 for detecting the hydraulic pressure of the hydraulic circuit 6 in the control device 11, a braking torque sensor 10 for detecting the braking torque applied by the brake caliper 2 and a brake switch 20 for detecting the depression of the brake pedal 48. Detection signals are input, and the control device 11 determines the situation in which the wheels are likely to lock based on these detection signals and drives the electromagnetic cut valve 7 to close. The electromagnetic cut valve 7 has a position a for connecting the master cylinder 5 and the brake caliper 2 and a position b for disconnecting the master cylinder 5 and the brake caliper 2 via the check valve 49.

In FIG. 2, reference numeral 21 is an axle of a front wheel of a motorcycle, 22 is a front fork supporting the axle 21, and 23 is a front fork.
Is a brake disc that rotates integrally with a front wheel (not shown). The base end of the support spring 4 is fixed to the lower end of the front fork 22 with a bolt 41, and the base end of the link 3 is fastened with a bolt 42 to the free end of the support spring 4 protruding rearward of the vehicle body. The link 3 is coupled to the support spring 4 and is supported so as to be displaceable in the direction indicated by the arrow in the figure. The support spring 4 is formed of a plate-shaped elastic member and generates an elastic restoring force proportional to the displacement of the free end in the bending direction.

A brake caliper 2 for braking a brake disc 23 is fixed to the link 3 via a bolt 24, and a bracket 25 projecting rearward is formed in a cylindrical outer shape in the middle of the front fork 22. The formed cylinder body 26 is swingably connected via a pin 27. A rod 28 slidably projects from the lower end of the cylinder body 26, and its tip is swingably connected to the link 3 via a pin 29. The brake caliper 2 and the rod 28 are attached to the link 3 supported by the free end of the support spring 4 and supported so as to be displaceable in the direction along the circumference of the brake disc 23.

As shown in FIG. 3, the feedback piston 8 is caulked and fixed to the upper end of the rod 28, and the feedback piston 8 is slidably accommodated in a cylinder 31 formed in a cylinder body 26 via a piston ring 32. An oil chamber 33 defined between the two communicates with the hydraulic circuit 6 via a through hole 34. The cylinder body 26 is provided with an O-ring 35, an annular seal case 36, and a seal 37 slidingly contacting the rod 28, and the rod 28 projects from a rod guide 38 fastened below the cylinder body 26.

In FIG. 2, 43 is a pipe connecting the oil chamber 33 and the brake caliper 2, and 44 is an oil chamber 33.
And a pipe for connecting the electromagnetic cut valve 7 with the electromagnetic cut valve 7. Also, 4
Reference numeral 5 is a dust boot for preventing foreign matter from entering.

With the above construction, the operation will be described below.

During normal traveling, the electromagnetic cut valve 7 maintains the position a where the master cylinder 5 and the brake caliper 2 communicate with each other without being energized. When the brake pedal 48 is depressed in this state, the hydraulic pressure of the hydraulic oil supplied from the master cylinder 5 to the brake caliper 2 rises, and the brake disc 23 is braked with a braking torque proportional to the hydraulic pressure.

As a reaction of this braking force, a braking torque is generated between the wheel and the road surface, and this braking torque is transmitted to the rod 28 via the wheel, the brake caliper 2 and the link 3 to support the base end of the link 3. The feedback piston 8 is pushed into the cylinder body 26 while bending the free end of the supporting spring 4 upward in the figure. Then, the feedback piston 8 stops at a position where the elastic restoring force of the support spring 4 and the hydraulic pressure of the oil chamber 33 acting on the feedback piston 8 are balanced with respect to the braking torque. If the hydraulic pressure or the braking torque changes from this position, the feedback piston 8
Moves to another equilibrium point by further sliding in the cylinder body 26.

When the wheels are likely to lock during the braking, for example, when the detection signal of the brake switch 20 indicating that the brake pedal 48 is stepped on is ON, the detection value of the hydraulic pressure sensor 9 exceeds the predetermined value, and When the detected value of the braking torque sensor 10 is less than the predetermined value, the control device 11 determines that the wheels are in the locked state, and the electromagnetic cut valve 7
To the brake caliper 2 from the master cylinder 5
The hydraulic oil guided to (1) is switched to a position (b) where it is shut off via a check valve 49 to prevent the wheel from being locked.

That is, the electromagnetic cut valve 7 is closed while the hydraulic pressure introduced to the brake caliper 2 is kept high.
When the wheels are about to lock and the slip ratio between the wheels and the road surface increases, the braking torque decreases, the braking torque applied to the rod 28 also decreases, and the feedback piston 8 via the link 3 by the elastic restoring force of the support spring 4 and the hydraulic pressure. Is extended to enlarge the oil chamber 33, and the hydraulic pressure of the hydraulic circuit 6 guided to the brake caliper 2 is temporarily reduced to prevent the wheels from being completely locked.

On the other hand, the braking torque also decreases as the hydraulic pressure is reduced, and when the slip ratio between the wheels and the road surface decreases to a predetermined value, the wheels are accelerated and the braking torque increases again. The rod 28 is the cylinder body 26
The feedback piston 8 is pushed into the oil chamber 33.
Sliding in the direction to reduce the oil pressure. The feedback piston 8 repeatedly expands and contracts the oil chamber 33 to stop the vehicle while controlling so that the friction coefficient between the wheel and the road surface does not exceed the maximum slip ratio.

By the way, the free end of the support spring 4 is displaced in the vertical direction in FIG. 2 as the braking torque is increased or decreased,
Since the support spring 4 is displaced only in accordance with the applied load, the hysteresis as shown in FIG. 7 does not occur and the hydraulic pressure controlled by the feedback piston 8 can be set to an appropriate value, and the antilock It is possible to exert the function stably.

Further, since the feedback piston 8 is attached to the link 3 connected to the free end side of the support spring 4, it is not necessary to house the elastic member for urging the feedback piston 8 in the cylinder body 26, and the structure is simplified. Therefore, it is possible to reduce the weight. Furthermore, at the top dead center and the bottom dead center of the feedback piston 8,
Since it is possible to suppress excessive fluctuations of the support spring 4, it is not necessary to provide the support spring 4 with a member that restricts excessive displacement.

Next, FIG. 4 shows another embodiment of the first embodiment.
The support spring 4 in the above embodiment is formed by the support spring 40 extended to the rear of the vehicle body, and the brake caliper 2 and the feedback piston 8 are attached to the support spring 40 so that the link 3 is unnecessary. This is the same as the first embodiment.

In this case, the link 3 in the first embodiment is unnecessary, the number of components can be reduced, and cost reduction and weight reduction can be promoted.

FIG. 5 shows still another embodiment, in which the first
Front fork 22 to which the base end of the support spring 4 in the second embodiment or the support spring 40 in the second embodiment is attached
While a predetermined concave portion 22a is provided at the lower end of the adjusting spring 43, the adjusting screw 43 is passed through and screwed into a position corresponding to the concave portion 22a on the base end side of the support spring 4, and the tip end 43a of the adjusting screw 43
The gap .DELTA.L between the concave portion 22a and the concave portion 22a can be adjusted, and other configurations are the same as those in the first or second embodiment.

By changing the length of the tip 43a of the adjusting screw 43 protruding upward in the figure, the gap ΔL also changes, and as shown in FIG. 6, the spring characteristic of the support spring 4 or 40 is widely changed according to the gap ΔL. Therefore, one type of support spring 4 or 40 can be used for a plurality of vehicle types, and the manufacturing cost can be reduced. After adjusting the adjusting screw 43 to the desired clearance ΔL, the nut 44
The adjustment screw 43 to support the spring 4 or 40
Fixed to.

[0029]

As described above, according to the present invention, the brake caliper and the feedback piston are attached to the free end side of the elastic member to suppress the occurrence of hysteresis due to the elastic member slidingly contacting the surrounding members. The displacement associated with the contraction and extension of the piston and the displacement of the elastic member are equalized, whereby the hydraulic pressure can be accurately controlled, and the antilock function can be stably exhibited.

Further, since the elastic member is provided with the displacement amount adjusting means, it is possible to change the spring characteristic of the elastic member, and one kind of elastic member can be applied to a plurality of vehicle types, thereby reducing the manufacturing cost. It can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a side view of the front fork portion of the two-wheeled vehicle.

FIG. 3 is a cross-sectional view similarly including a hydraulic circuit.

FIG. 4 is a side view of a front fork portion of a two-wheeled vehicle showing another embodiment.

FIG. 5 is a side view of a front fork portion of a two-wheeled vehicle showing yet another embodiment.

FIG. 6 is a diagram showing the relationship between the displacement of the support spring and the load.

FIG. 7 is a diagram showing a relationship between a displacement of a support spring and a load showing a conventional example.

[Explanation of symbols]

 2 brake caliper 3 link 4 support spring 5 master cylinder 6 hydraulic circuit 7 electromagnetic cut valve 8 feedback piston 9 hydraulic sensor 10 braking torque sensor 11 controller 20 brake switch 22a recess 26 cylinder body 43 adjusting bolt

Claims (2)

[Claims] 1. An electromagnetic cut valve that opens and closes a hydraulic circuit connecting a master cylinder and a brake caliper, a feedback piston that also changes the volume of the hydraulic circuit according to the displacement of the brake caliper, and a hydraulic pressure that detects the hydraulic pressure introduced to the brake caliper. A sensor and a braking torque sensor for detecting a braking torque applied by the brake caliper,
Control means that closes the electromagnetic cut valve when the wheels are locked based on these detection signals and the base end is fixed to the vehicle body side, while the free end side can displace the brake caliper and feedback piston according to the braking torque. An antilock brake device, comprising: an elastic member that supports the antilock brake device. 2. The anti-lock brake device according to claim 1, further comprising a displacement amount adjusting unit that regulates a displacement amount of the elastic member.