JP2682673B2 - Anti-lock brake - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an anti-lock brake that prevents a tire from becoming locked due to braking in a motorcycle or the like.

(Prior Art) As an anti-lock brake for motorcycles, etc., a fifth passage is provided in the brake oil supply passage from the master cylinder to the brake caliper.
The one in which an anti-lock valve as shown in the figure is interposed is proposed by the present applicant as Japanese Patent Application No. 62-251128.

This anti-lock valve has a pressure regulator valve 51, which serves as a regulator valve for controlling the brake oil pressure, and a pressure cut valve 19 housed in an integrated valve housing 10. The valve housing 10 has an inflow that communicates with a master cylinder. A port 14 and an outflow port 15 communicating with the brake caliper are formed, and inside the valve housing 10, a passage 16 constantly communicating with the inflow port 14 and a passage 17 always communicating with the outflow port 15 are formed.

The pressure cut valve 19 is provided between the inflow port 14 and the passage 17, and the spring 24 accommodated inside the bellows 50 provided opposite to the pressure cut valve 19 connects the pressure cut valve 19 to the return spring 21.
By pressing against, the valve is held in the valve open position when not braking. When the braking oil pressure in the inflow port 14 rises due to the braking operation, the bellows 50 contracts against the spring 24 due to this pressure, and the pressure cut valve
19 is biased by the return spring 21 to close the valve. The inside of the bellows 50 is open to the atmosphere.

On the other hand, the pressure regulator valve 51 includes the passage 16 and the outflow port 15
The return spring 30 holds the valve-closed position during non-braking. Further, the position detection rod 11 for controlling the opening / closing of the pressure regulator valve 51 is slidably inserted into the valve housing 10 from the outer side in opposition to the pressure regulator valve 51. The position detection rod 11 is configured to be displaced in the axial direction in conjunction with the displacement of the brake caliper that is displaceably supported according to the braking torque, and enters the valve housing 10 as the braking torque increases. A plate-shaped sliding portion 54 is slidably housed inside the tip of the position detection rod 11, and a spring housed inside the bellows 52.
36 is elastically supported by the pressure regulator valve 51. The inside of the bellows 52 is exposed to the atmosphere like the bellows 50.

When the brake operation is performed, the brake fluid sent from the master cylinder to the inflow port 14 is released by the pressure cut valve 19
Is supplied from the outflow port 15 to the brake caliper via the passage 17 and generates a braking torque. Then, the position detection rod 11 enters the valve housing 10 in conjunction with the displacement of the brake caliper corresponding to the braking torque, and the plate-shaped sliding member 54 pushes the pressure regulator valve 51 open via the rod 33. On the other hand, the bellows 50 contracts due to the increase in the brake oil pressure in the inflow port 14, and the pressure cut valve 19 closes. The spring load of the spring 36 is preset so that the opening of the pressure regulator valve 51 and the closing of the pressure cut valve 19 occur at the same time. Further, the braking oil pressure at this time is set to a low pressure that does not lock the tire even on a low μ road with a large slip ratio, and after the braking oil pressure exceeds this set pressure, the braking oil in the inflow port 14 flows through the passage 16. Outflow port through
Supplied to 15.

By the way, as the braking torque increases, the position detection rod
11 enters the inside of the valve housing 10, but at the same time, the plate-like sliding member 54 moves from the pressure regulator valve 51 to the outflow port 15
Due to the increase in the pressure of the braking fluid flowing to the position, the position detection rod 11 is retracted from the tip end against the spring 36.

In this case, the braking torque of the brake caliper does not rise to a certain extent due to tire slip even if the braking oil pressure is increased, and therefore the position detection rod 11 does not penetrate into the valve housing 10 more than a certain amount. However, on the other hand, the plate-like sliding member 54 retracts as long as the braking fluid pressure increases. Therefore, the position detection rod should be closed so that the pressure regulator valve 51 closes when the braking torque reaches the maximum value.
The positional relationship of 11 with respect to the pressure regulator valve 51 is set. That is, when the master cylinder is pressurized beyond the maximum torque, the pressure regulator valve 51 is closed and the supply of the brake fluid to the brake caliper is cut off, so that the tire is not locked.

Since the slip ratio of the tire is high on a wet road surface or a gravel road, the displacement of the brake caliper is small for the same braking oil pressure, and the position detection rod 11 does not easily enter the valve housing 10. Therefore, the pressure regulator valve
The 51 closes at a lower pressure, so the anti-lock feature still works when the track conditions change.

(Problem of the invention) In this anti-lock brake, for example, when the brake is used to prevent the two-wheeled vehicle stopped in the middle of the uphill from moving backward, the braking torque acts in the direction opposite to the normal braking, Detection rod 11 is valve housing 10
It is displaced in the direction to exit from. Therefore, the pressure cut valve
Even when 19 is closed, the pressure regulator valve 51 does not open, and the braking fluid pressure transmitted to the brake caliper does not rise any further, so there is a problem that the braking torque tends to become insufficient.

SUMMARY OF THE INVENTION In order to solve the above problems, it is an object of the present invention to provide an antilock brake having a structure that does not limit the brake fluid pressure for braking against reverse.

(Means for Achieving the Problem) The present invention provides a brake caliper that is displaceably mounted according to a control torque, and a position detection rod that responds to the displacement of the brake caliper, and a brake caliper that responds to the displacement of the position detection rod. In an anti-lock brake equipped with a regulator valve that controls the supplied brake fluid pressure, a bypass passage that bypasses the regulator valve is provided, and this bypass passage is closed by another valve and linked with the displacement of the position detection rod. And means for opening the additional valve only when the vehicle is being braked for backward movement.

(Operation) In braking when the vehicle moves backward, the position detecting rod is displaced in the opposite direction as the brake caliper generates a braking torque in the opposite direction to the braking when moving forward. In conjunction with this displacement, the opening means opens the valve of the bypass passage, so that the braking oil is directly supplied to the brake caliper without passing through the regulator valve. For this reason, the pressure of the brake fluid is not limited in the braking for the backward movement of the vehicle, and sufficient braking torque can be obtained.

(Embodiment) FIGS. 1 to 4 show an embodiment of the present invention. The same components as those in the conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the antilock valve shown in FIG. 1, the pressure cut valve 19 provided between the inflow port 14 and the passage 17 is configured as a plate valve in which a rod 25 is fixedly mounted at the center, and a spring 24 housed in a bellows 50. By urging the rod 25 in the valve opening direction, the rod 25 is held in the valve opening position during non-braking. The passage 17 communicates with the outflow port 15 shown in FIG.

Between the passage 16 communicating with the inflow port 14 and the outflow port 15, a pressure regulator valve 51 similar to the conventional example is provided. A hollow spool 13 is screwed onto the tip of a position detection rod 11 inserted into the valve housing 10 opposite to the pressure regulator valve 51, and a plate-like sliding member 54, a bellows 52 and a spring 36 form the spool. It is housed in the hollow portion 32 of 13. The position detection rod 11 slidably penetrates the inside of a holder 22 that is screwed into the valve housing 10,
The braking torque support springs 12 and springs 20 disposed on both sides of the spring 22 are held in a balanced position.

The base end of the position detection rod 11 is an axle 1 as shown in FIG.
It is connected to the end of a link 5 which is rotatably supported by the. On the other hand, the end of the valve housing 10 located on the opposite side of the position detection rod 11 is connected to a bracket 9 provided in the middle of the front fork 2 supporting the axle 1. A brake caliper 4 that brakes the brake disc 3 is attached to a link 5, and a pipe 6 that supplies braking oil to the brake caliper 4 is connected to an outflow port 15 of a valve housing 10. The inflow port 14 of the valve housing 10 is connected to the master cylinder 7 via the pipe 8.

The valve housing 10 has these inlets and inlet ports
A bypass port 18 is formed in addition to 14 and 15. The bypass port 18 communicates with the inflow port 14 via the bypass passage 26, and opens on the downstream side of the pressure regulator valve 51 inside the valve housing 10 (in communication with the outflow port 15).

A check valve 23 is provided in the bypass port 18 as a means for closing the bypass passage 26. further. An annular groove 13A is formed on the outer circumference of the spool 13 as a means for opening the check valve 23 according to the displacement of the position detection rod 11. As shown in FIG. 2, the check valve 23 is biased by the return spring 27 toward the outer circumference of the spool 13 and is closed with its tip protruding into the annular groove 13A. Further, the check valve 23 is opened by moving the tip of the spool 13 from the annular groove 13A to the outer peripheral portion of the spool 13 by axial displacement of the spool 13, and the bypass passage 26 communicates with the outflow port 15. In addition, spool 13
As long as is displaced from the neutral position in the direction of the pressure regulator valve 51, the tip of the check valve 23 remains in the annular groove 13A, and the spool 13 is displaced in the opposite direction from the neutral position so as to jump out of the annular groove 13A. The width and position of the annular groove 13A are determined.

 Next, the operation will be described.

During non-braking, the pressure regulator valve 51 is held in the closed position by the return spring 30, and the pressure cut valve 19 is held in the open position by the spring 24, as shown in FIG. Further, as the tip of the check valve 23 projects inside the annular groove 13A as shown in FIG.
3 are also closed.

If the braking operation is performed while traveling forward in this state, the pressure cutoff valve 19 is closed due to the increase of the braking oil pressure to the set value, and at the same time, the pressure regulator valve 51 is opened, and the master cylinder 7
The braking oil guided from the inflow port 14 through the passage 16 and the pressure regulator valve 51 is supplied from the outflow port 15 to the brake caliper 4 through the pipe 6. With the generation of the braking torque, the brake caliper 4 is rotationally displaced together with the link 5 in the direction of the arrow in FIG. 3, and the position detection rod 11 connected to the end of the link 5 enters the valve housing 10.
Along with this, the annular groove 13A of the spool 13 is displaced toward the pressure regulator valve 51 side, but the tip of the check valve 23 remains inside the annular groove 13A, and the check valve 23 remains closed. Therefore, during the braking during forward movement, the brake oil is not supplied through the bypass passage 26, and the pressure regulator valve 51 and the position detection rod 11 perform the same antilock control of the brake oil pressure as in the conventional example.

On the other hand, when braking is applied to prevent backward movement on an uphill or to brake the reverse, the braking oil sent from the master cylinder 7 to the inflow port 14 first passes through the pressure cut valve 19 and the passage 17 and then to the outflow port 15. Is supplied to the brake caliper 4 to generate a braking torque.

Due to the reaction force of the braking torque, the brake caliper 4 is rotationally displaced together with the link 5 in the direction opposite to the arrow in FIG. 3, and the position detection rod 11 and the spool 13 are resisted against the spring 20 in the retreating direction from the valve housing 10. Displace. As a result, the moving annular groove 13A is disengaged from the tip of the check valve 23, and the tip of the check valve 23 is located outside the annular groove 13A.
By riding on the outer peripheral portion of 3, the check valve 23 retracts and opens. This allows inflow port 14 and outflow port
15 communicates with each other via the bypass passage 26, and the brake oil from the master cylinder 7 is directly supplied to the outflow port 15 without passing through the closed pressure regulator valve 51.

When the brake fluid pressure in the inflow port 14 rises to the set pressure, the pressure cut valve 19 closes, but if the spring characteristic of the spring 20 is set so that the check valve 23 is already open at this stage, the brake The supply of the braking oil to the caliper 4 is not interrupted, and a sufficient braking pressure according to the braking operation is supplied.

FIG. 4 shows another embodiment in which the bypass passage 26 is connected to the bypass port 18 and the upstream side of the pressure regulator valve 51. Since the upstream side of the pressure regulator valve 51 is always in communication with the inflow port 14 via the passage 16, the bypass passage 26 can be arranged in this way. In this case,
Since the bypass passage 26 is formed inside the valve housing 10, external piping can be reduced, the external shape of the device can be made compact, and the layout can be facilitated.

(Effects of the Invention) As described above, in the present invention, in the anti-lock brake including the regulator valve that controls the pressure of the brake fluid supplied to the brake caliper in conjunction with the position detection rod, the bypass passage bypassing the regulator valve is provided. Since the bypass passage is closed by another valve and the means for opening the other valve only when braking the vehicle in reverse is interlocked with the position detection rod, the anti-regulator valve anti By the lock function, proper pressure is supplied to the brake caliper so as not to lock the tire, while sufficient braking pressure is supplied to the brake caliper through the bypass passage without restriction when the vehicle is braked in reverse. For this reason, when the brake is used for the purpose of preventing backward movement after stopping the vehicle on an uphill or when the brake is applied to the backward movement, the fear of insufficient braking force which is often caused by the antilock brake is eliminated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an antilock valve showing an embodiment of the present invention, FIG. 2 is a view taken along the line AA in FIG. 1, and FIG. 3 is a motorcycle showing the arrangement of the antilock valve and a position detection rod. FIG. 4 is a side view of the main part of the front wheel, and FIG. 4 is a sectional view of an antilock valve showing another embodiment. FIG. 5 is a sectional view of an antilock valve showing a conventional example. 4 ... Brake caliper, 5 ... Link, 7 ... Master cylinder, 10 ... Valve housing, 11 ... Position detection rod, 13 ... Spool, 13A ... Annular groove, 14 ... Inflow port, 15 ... Outflow port, 16, 17 ... Passage, 18 ... Bypass port, 19 ... Pressure cut valve, 23 ... Check valve,
26 …… Bypass passage, 51 …… Pressure regulator valve.

Claims (1)

(57) [Claims] 1. A brake caliper is mounted so as to be displaceable in accordance with a control torque, and a position detection rod which responds to the displacement of the brake caliper and a braking oil pressure supplied to the brake caliper are controlled in accordance with the displacement of the position caliper. In an anti-lock brake equipped with a regulator valve, a bypass passage that bypasses the regulator valve is provided, and this bypass passage is closed by another valve. An anti-lock brake characterized in that it is provided with a means for opening the other valve only.