JPS6226938B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a master cylinder for two-wheeled vehicles.

Generally, the braking system of a two-wheeled vehicle is separated into a front wheel system and a rear wheel system, and the two are used selectively depending on speed and road surface conditions. For this reason, those with excellent driving skills can make full use of their driving techniques by skillfully using both, but those with poor driving skills, such as beginners, use the rear brakes exclusively to avoid falling due to the front wheels locking. Braking efficiency tends to be used frequently, and braking efficiency cannot be fully demonstrated.

Therefore, in order to increase braking efficiency, there is a system in which a braking mechanism is constructed using a tandem master cylinder for two-system control of the front and rear wheels, so that the rear wheel brake and the front wheel brake are interlocked. (For example, Utility Model Publication No. 49-42383).

However, as shown in the above publication,
If the front and rear wheel hydraulic pressures are linked and controlled at the same time using force input from one location, the effectiveness of the front and rear brakes will always be the same, and both brakes will be used separately. This makes it impossible to maneuver using technique, and the function of the braking system is reduced by half. Further, in sudden braking, etc., one braking input is used for two systems, which may lead to insufficient braking force.

The purpose of this invention is to eliminate the above problems,
To provide a master cylinder which can not only interlock front and rear wheel brakes but also actuate only one brake or change the braking force.

Hereinafter, the configuration of the present invention will be explained based on the accompanying drawings.

The master cylinder of this invention is constructed by combining two master cylinders. As shown in FIG. 1, one of the master cylinders A has a first piston 2 inserted into the closed end of the cylinder 1, and a second piston 3 inserted into the open end. A first pressure chamber 4 is formed between the first piston 2 and the closed end, and a second pressure chamber 5 is formed between both pistons 2 and 3.

An annular groove 6 is provided on the outer periphery of the first piston 2, and this annular groove 6 communicates with a brake oil tank 8 through a small hole 7 provided in the cylinder 1. Second
The pressure chamber 5 communicates with the annular groove 6 through a communication passage 9 provided in the first piston 2 .

A proximity valve 10 for opening and closing the communication passage 9 is provided within the second pressure chamber 5. In the illustrated case, the proximity valve 10 has the following structure.

That is, the cups 11, 11' are provided on the opposing surfaces of the first piston 2 and the second piston 3, respectively, and the coil springs 12 are compressed and fitted between them, thereby fixing the cups 11, 11'. The coil spring 12 is connected to both pistons 2 and 3.
It also has the effect of receding. Each cup 11,
A valve rod 13 freely passes through 11', and a valve 14 is provided at the end of the valve rod 13 on the first piston 2 side, and a stopper 15 is provided at the other end. Further, a packing 15' is attached around the valve 14.

The valve 14 is constantly pushed in the direction of the first piston 2 by a conical coil spring 16 compressed and fitted between the valve 14 and the inner surface of the cup 11.
Since the pressing force of this spring 16 is considerably smaller than the pressing force of the coil spring 12 described above, in a steady state, the stopper 15 of the valve rod 13
is engaged with the cup 11', and the valve 14 is connected to the communication passage 9.
It is stationary near the open end of the.

The above-mentioned proximity valve 10 has a second pressure chamber 5 when the first piston 2 and the second piston 3 approach each other.
The communication passage 9 is closed so that the oil inside does not flow back into the tank 8.

On the other hand, in the annular groove 6 of the first piston 2,
A stopper 17 protruding from the inner wall of the cylinder 1 is fitted. This stopper 17 is connected to the first piston 2
When the first piston 2 is in a steady state, the first piston 2 is unable to move back any further because it is engaged with the peripheral wall of the annular groove 6 near the second pressure chamber 5.

In FIG. 1, the aforementioned first pressure chamber 4 is provided with an inlet 19 for brake oil, and the second pressure chamber 5 is provided with an outlet 20. Others, 21 in the figure
indicates a cup seal, and 22 indicates a stop ring of the second piston 3. Further, on the outer surface of the second piston 3, there is a hole 23 for inserting a bushing rod, etc.
is provided.

In the master cylinder having the above configuration, when the second piston 3 is stationary, the inlet 19
When hydraulic pressure is received from the first piston 2, the first piston 2 operates and sends out pressure oil from the outlet 20.

When the second piston 3 is pressed by a push rod or the like, the first piston 2, which is blocked by the fixed stopper 7, does not operate, and only the second piston 2 compresses the coil spring 12 and moves forward. , the communication passage 9 is closed by the valve 14, and pressure oil is sent to the outlet 20.

Next, an explanation will be given of the operation when hydraulic pressure is applied to the inlet 19, thereby pressing the first piston 2, and at the same time, the second piston 3 is also pressed by a push rod or the like.

When the pressure in the second pressure chamber 5 is higher than the pressure in the first pressure chamber 4, the high pressure in the second pressure chamber 5 is sent out from the outlet 20; When the pressure is higher than the pressure in the chamber 5, the first piston 2 moves toward the second pressure chamber, and pressure oil is sent out from the outlet 20 with the pressures in both pressure chambers equalized.

FIG. 2 and FIG. 3 both show that the above-mentioned master cylinder A is combined with a second master cylinder B,
The master cylinder of the present invention is constructed and shown assembled to a two-wheeled vehicle. The second master cylinder B has a single piston 60 and a brake oil outlet 6
This is a conventionally known master cylinder having 1.

In the case of FIG. 2, the brake lever 50 and the second piston 3 of the master cylinder A are mechanically connected by the aforementioned push rod or the like, and the outlet 20
is connected to the front wheel brake 51. The inlet 19 is connected to the outlet 61 of the second master cylinder B by an oil passage 52, and a pedal 53 is mechanically connected to the inlet of the second master cylinder A. The middle of the oil passage 52 is divided and connected to a rear wheel brake 55 via a pressure reducing valve 54. However, the pressure reducing valve 54 may be omitted in some cases.

The brake operation when the master cylinders A and B are arranged and connected as shown in FIG. 2 will be explained. First, when only the pedal 53 is depressed, the hydraulic pressure generated in the second master cylinder B operates the rear wheel brake 55 via the pressure reducing valve 54. At the same time, the first piston 2 operates, pressure oil is also sent out from the outlet 20, and the front wheel brake 51 also operates.

On the other hand, when only the handle lever 50 is squeezed, only the second piston 3 of the master cylinder A operates.
Only the front wheel brake 51 is operated.

Further, when both the pedal 53 and the handle lever 50 are operated simultaneously, the second master cylinder B operates the rear wheel brake 55. Also, at this time, if the pressure in the second pressure chamber 5 is higher than the pressure in the first pressure chamber 4 in the first master cylinder A, only the second piston 3 operates on the first master cylinder side, and high-pressure oil pressure is applied to the front wheels. Since the front wheel brake 51 is sent to the front wheel, the force of the front wheel brake 51 increases. Further, if the pressure in the first pressure chamber 4 is large, the first piston 2 and the second piston 3 operate together, and the same pressure as that in the master cylinder B is sent to the front wheel brake 51.

FIG. 3 shows a case where the second master cylinder B is connected to the handle lever 50 side, the pedal 53 is connected to the second piston 3 of the first master cylinder A, and the outlet 20 is connected to the rear wheel brake 55 side. . The operation in this case is almost the same as in the case of FIG. 2, so the explanation thereof will be omitted.

As described above, according to the present invention, when a braking input is applied to the second piston 3 of the master cylinder A, only one of the front and rear brakes is activated, and the piston 60 of the master cylinder B is applied with a braking input. When an input is applied, both the front and rear brakes are operated in conjunction with each other, and when a braking input is applied to both the second piston 3 and the piston 60, the first brake is activated depending on the magnitude of the input. 1 On the master cylinder A side, either only the second piston 3 or both the second piston 3 and the first piston 2 operate, so that the brake pressure of the front and rear wheels can change or become the same pressure. , fine-grained braking that uses the brake handle and brake pedal differently, sudden braking that rapidly increases the hydraulic pressure of the front and rear brakes, and braking that stabilizes the distribution of brake force between the front and rear wheels even if the steering technique is insufficient. This has the effect of making things possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one of the two master cylinders constituting the master cylinder of the present invention, and FIGS. 2 and 3 show the master cylinder of the present invention assembled into a two-wheeled vehicle. FIG. 1... Cylinder, 2... First piston, 3...
Second piston, 4... First pressure chamber, 5... Second pressure chamber, 6... Annular groove, 8... Tank, 9... Communication passage, 10... Proximity valve, 17... Fixed stopper, 18 ...Movable stopper, 19...Entrance, 20
...Outlet, 52...Oil passage, A...Master cylinder, B...Second master cylinder, 60...Piston, 61...Outlet.

Claims (1)

[Claims] 1. A first piston 2 is inserted into the closed end of the cylinder 1 to form a first pressure chamber 4 between the closed end and the first piston 2, and a second piston 3 is inserted into the open end of the cylinder 1 to form a first pressure chamber 4 between the closed end and the first piston 2. A second pressure chamber 5 is formed between the pistons 2 and 3, and a proximity valve 10 is provided in the second pressure chamber 5 to open and close a communication passage 9 between the chamber and the brake oil tank 8. A stopper 17 for preventing the cylinder 1 from retracting from the state
A first master cylinder A has a structure in which a braking oil inlet 19 is provided in the first pressure chamber 4 and an outlet 20 is provided in the second pressure chamber 5, and a single piston 6.
0 and a second master cylinder B having a brake oil outlet 61;
A master cylinder for a two-wheeled vehicle, characterized in that the inlet 19 of the second master cylinder B and the outlet 61 of the second master cylinder B are connected through an oil passage 52.