JPH0194056A - Antilock brake - Google Patents

Abstract

PURPOSE:To perform braking operation with the optimum braking conformed to road conditions by installing a pressure responding member which is supported elastically on a position detecting rod and simultaneously opens or closes a check valve operating in response to pressure in a pressure chamber. CONSTITUTION:A piston 34 is pushed back against a spring 36 by an increase in brake pressure, a rod 33 is separated from a puppet 24, and opening of a pressure regulator valve 11 comes to zero. When this pressure regulator 11 is closed, a brake pressure value is specified by means of raising a spring constant of a cushion and so on. With this constitution, at a low mu road or the like, an increment of brake pressure grows according to pressurization of a master cylinder, but displacement of a position detecting rod 11B will not become larger as much as a high mu road because a slip factor is large. Consequently, since the pressure regulator valve 11 is closed to earlier, an antilock function is sufficiently maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in an anti-lock brake for a two-wheeled vehicle, which has a function of preventing tires from becoming locked during braking.

(Prior art) If the rotation of the wheel is locked by the brake when braking a two-wheeled vehicle, the tire is likely to slip or skid on the road. Brakes equipped with an anti-lock mechanism that controls braking torque are known (for example, Japanese Patent Laid-Open No. 60-25835 and Japanese Patent Laid-Open No. 61-110658).

(Problem to be solved by the invention) All of these anti-lock PIigs control the hydraulic pressure supplied for braking, but many devices such as pumps, accumulators, and solenoid valves are inserted in the hydraulic pressure supply path. In addition, it is necessary to separately provide a slip detection mechanism, which results in a complicated and expensive device and requires a large amount of space for installation.

SUMMARY OF THE INVENTION An object of the present invention is to provide an anti-lock brake for two-wheeled vehicles that has a simple structure and operates efficiently in order to solve the above-mentioned problems of conventional brakes equipped with an anti-lock mechanism.

(Means for solving problem α) The present invention provides a brake caliper that is displaceably mounted in accordance with braking torque, and a pressure chamber equipped with a check valve provided in the middle of a passage that supplies brake oil to the brake caliper. a position detection rod that expands and contracts the pressure chamber in conjunction with the displacement of the brake caliper; a pressure responsive member that is elastically supported by the position inspection rod and opens and closes the check valve in response to the pressure in the pressure chamber; An orifice is provided between the pressure responsive member and the pressure chamber to hydraulically regulate the displacement speed of the pressure responsive member.

(Function) During braking, the position detection rod is displaced in accordance with the displacement of the brake caliper, and the check valve is closed via the pressure-responsive member, thereby preventing an increase in braking torque just before the tire becomes locked.

Further, when the road surface friction coefficient changes during braking, the braking torque changes accordingly, and therefore the position detection rod also moves to try to adjust the braking pressure in the pressure chamber. At this time,
Due to the pressure change in the pressure chamber, the pressure responsive member tries to make a relative displacement in the direction to compensate for this, but the orifice interposed between it and the pressure chamber causes a delay in this relative displacement, and as a result, the pressure chamber volume changes in response to the road surface change. increase responsiveness.

(Example) 1 to 3 show PISi embodiments of the present invention.

In Figure 1, 1 is the axle of the front wheel of a two-wheeled vehicle, and 2 is the axle 1
The front 7 supports the front wheels, and 3 is a brake disc for braking that rotates together with the front wheels. A bracket 7 is provided rearwardly protruding from the lower end of the front 7 orifice 2, and the base end of the link 5 is rotatably attached to this bracket 7 via a pin 8. Brake disc 3 is attached to link 5
A brake caliper 4 for braking is fixed via bolts 6, and a bush 5 9 made of rubber or the like that comes into contact with the upper end of the brake caliper 4 is provided on the front fork 1 to protrude rearward. Furthermore, a valve block IIA with a sill-shaped outer shape is attached to another bracket 10 that protrudes backward above the cushion 9 of the front 7-hole 1.
are hinged. A position detection rod 11B protrudes freely from the valve block IIA, and its tip is hinged to the tip of the link 5.

Position detection rod IIB is located inside valve block IIA.
A pressure regulator valve 11 that opens and closes according to axial displacement is housed therein. Brake caliper 4 is brake sill 4
It operates by receiving braking oil pressure from a mask shilling (not shown in figure A), and a piping 12 which is a passage for braking oil for this purpose is disposed through this pressure regulator valve 11. Note that 13 is a pressure cut valve attached to the pressure regulator valve 11.

The internal structures of the pressure regulator valve 11 and the pressure cut valve 13 are shown in FIG. The pressure cut valve 13 located on the upstream side bypasses the pressure regulator valve 11 and the passage 16 communicating with the upstream side of the pressure regulator valve 11 according to the pressure of the brake oil supplied from Musk Schilling to the inlet boat 14. A poppet 19 that slides in a direction perpendicular to the inlet boat 14 is provided in a valve chamber 18 formed facing the inlet port 14 and selectively supplies the passage 17 leading to the downstream outlet boat 15. A seat 20 with a circular opening in the valve chamber 18 facing the poppet 19 is formed. A passage 16 opens in the valve chamber 18 facing the side surface of the poppet 19, and is always in communication with the inlet boat 14. There is a poppet 19 between the poppet 19 and the rear plug 40.
Pressure from the inlet port 14 is guided through a port 19A formed in the poppet 19A, and a spring 21 is interposed to bias the poppet 19 toward the seat 20.

The repulsive force of the spring 21 is so weak that the poppet 19 functions as a check valve for the passage 17.

In addition, a sliding hole 2 is provided on the opposite side across the valve chamber 18 and the valve chamber 20.
2 is formed, and a spool 23 is housed inside the spool 23 so as to be freely slidable. The spool 23 is urged toward the poppet 19 by a spring 24 interposed between the spool 23 and the plug 41 at the rear, and a mouth 7 door 25 is fixed to the tip of the spool 23. The back side of the spool 23 is open to the atmosphere, and the spool 23 and the sliding hole 2
A seal 26 is interposed between the two. Also, spool 2
A passage 17 opens in the sliding hole 22 at the front of 3.

On the other hand, the pressure regulator valve 11 includes a poppet 28 and a seat 29 in a valve chamber 27 similar to the pressure cut valve 13, and a passage 16 opens in the valve chamber 27. The poppet 28 is biased toward the seat 29 by a low-pressure spring 30 interposed between the poppet 28 and the plug 42 behind it, and functions as a check valve that shuts off the passage 16 from the upstream side. The inside and outside of the poppet 28 communicate with each other via a boat 28A.

Further, the position detection port-rad 11B is inserted into a seal 3 in a sliding hole 31 formed on the opposite side of the valve chamber 27 by sandwiching the seat 29.
It is inserted and held in a freely slidable manner via 8. The passage 17 and the outlet boat 15 connected to the brake cylinder 4A open in the pressure chamber 31A provided in the sliding hole 31 in front of the insertion of the position detection rod 11B.

A sliding hole 32 is formed inside the insertion end of the position detection rod IIB, and a piston 34 as a pressure responsive member is housed inside the sliding hole 32 via a seal 35 so as to be freely slidable in the axial direction. A rod 33 is provided on the piston 34 to protrude toward the poppet 28, a sliding hole 32 at the back of the piston 34 is open to the atmosphere, and a spring 36 is housed inside the rod 33 for biasing the piston 34 toward the poppet 28. be done. A ring 37 is caulked and fixed to the tip of the sliding hole 32. this ring 3
7 acts as a retainer for the piston 34 (and the gap between it and the a-rad 33 passing through the center functions as an orifice 37A that communicates the inside of L32 with the pressure chamber 31A).

Next, the effect will be explained.

Pressure regulator valve 1 during normal running without braking action
1 and the pressure cut valve 13 are in the state shown in FIG. That is, since no brake pressure is applied to the inlet boat 14, the pressure cut valve 13 maintains the poppet 19 via the rod 25 in the balanced position of the springs 21 and 24, and the inlet boat 14 communicates with both passages 16 and 17. There is. Further, the weight of the brake caliper 4 and the link 5 is applied to the position detection port γ door 11B connected to the tip of the link 5, so that the position detection port γ door 11B is in the state of being most protruded from the valve block IIA.

Therefore, the loft 33 is separated from the poppet 28, and the poppet 28 is urged by the spring 30 and seats on the seat 29, closing the passage 16, leaving only the passage 17 at the entrance boat 1.
4 and the exit boat 15 are communicated with each other.

When the brakes are applied from this state, the pressure in the valve chamber 18 and sliding hole 22 of the pressure cut valve 13 rises due to the braking oil sent from the mask cylinder to the inlet boat 14, and the spool 23 with its back surface open to the atmosphere increases. It resists the spring 241 and retreats together with the rod 25. Since the inside and outside of the poppet 19 communicate through the bow 19A, the pressure is equal, so when the rod 25 retreats, the poppet 19 is urged by the spring 21 and seats on the seat 20, and the passage 17 cut off.

On the other hand, the brake oil sent into the passage 17 before this shutoff is supplied to the brake caliper 4 through the outlet boat 15 and the piping 12, and exerts a braking torque on the brake disc 3, and the brake caliper 4 receives this reaction force. While elastically deforming the cushion 9, it is rotationally displaced in the counterclockwise direction in FIG. 1 about the pin 8 as a fulcrum, thereby compressing the position detection rod IIB.

As a result, the position sensing rod IIB retracts the poppet 28 from the seat 29 via the rod 33 and communicates the passageway 16 with the exit boat 15.

In addition, with respect to the brake pressure Pc at the time when the pressure cut valve 13 retreats the spool 23 and seats the poppet 19 on the seat 20, in the pressure regulator valve 11, the spring 36 is Fr=PcXA (A: pressure receiving area of the piston 34 )'s spring load is initially set. Furthermore, the sliding distance of the position detection rod IIB from the no-load state to the pressure Pc is the same as that between the rod 33 and the poppet 2 in the no-load state.
The elasticity of the cushion 9 is set to be equal to the separation distance from the cushion 9.

Under the above settings, the brake pressure after braking starts is Pc
The brake oil in the mask cylinder is supplied to the brake caliper 4 through the passage 17 until the pressure reaches Pc, and when the pressure reaches Pc, the pressure regulator valve 11 opens at the same time as the pressure cut valve 13 closes, and the brake pressure that increases thereafter is It is transmitted to the brake caliper 4 mostly through the passage 16. Furthermore, due to the rising brake pressure, the piston 34 begins to move back together with the rod 33 against the spring 36.

By the way, the opening degree δ of the pressure regulator valve 11 in this state is brake pressure P=Pc+ΔP, position detection rod II
If the displacement of B is Δχ and the spring constant of the spring 36 is Ks, then δ=Δχ−(A/Ks)·ΔP (1).

Here, as the brake pressure increment ΔP increases, the braking torque increases, and as a result, Δχ also increases.

On the other hand, the relationship between braking torque T and tire slip rate S is shown in the graph of FIG. μ indicates the coefficient of friction between the road surface and the tires. When the braking torque T is increased on a normal road surface, the tires lock after a certain value and the slip rate rapidly increases, and thereafter the braking torque T shows a slight decrease. Therefore,
If the opening degree of the pressure regulator valve 11 is set to δ = 0 near the maximum torque on the high μ road in the graph, the transmission of pressure to the brake caliper 4 will be cut off even if the mask shilling is pressurized from now on, and the tire pressure will be reduced. It doesn't reach lock. Specifically, the piston 34 is pushed back against the spring 36 due to the increase in brake pressure, and the rod 33 is separated from the poppet 28 by being displaced in the opposite direction to the compressive displacement of the position detection rod IIB, and the poppet 28 is moved away from the poppet 28. After sitting on the seat 29, the opening degree of the pressure regulator valve 11 becomes zero. The brake pressure value at which the pressure regulator valve 11 closes is set by increasing the spring constant of the cushion 9 or by providing a stopper that restricts the rotational displacement of the link 5 to suppress an increase in the first term Δχ in equation (1). This is achieved by increasing the fiS2 term faster than the PIS1 term.

Note that when the characteristics of the pressure regulator valve 11 are set in this way, the brake pressure increment ΔP increases in accordance with the mask shilling pressurization on a low μ road or a wet road. The displacement Δχ of the position detection rod IIB that is displaced together with the caliper 4 is the slip rate S
Since is large, the high μ road does not become large. Therefore, the second term of equation (1) becomes equal to the first term at an early stage, and the opening degree of the pressure regulator valve 11 becomes δ=0. In other words, low μ
On roads or wet roads, the pressure regulator valve 11 closes with low brake pressure, so the anti-lock function is sufficiently maintained even under such conditions where the tires tend to lock.

Next, when the braking torque suddenly changes during braking, such as when entering from a high μ road to a low μ road, the reaction force of the braking torque suddenly decreases, and the brake caliper 4 is pushed back to the cushion 9 and moved into position. The displacement Δχ of the detection rod IIB suddenly decreases. Following this, the piston 34 retreats, and the poppet 2
8 sits on the seat 29 and cuts off the supply of brake pressure, and at the same time functions as a pressure reducing actuator that expands the volume of the pressure chamber 31A and reduces the pressure acting on the brake sill 4A.

Note that due to this decrease in brake pressure, the piston 34 is biased by the spring 36 and tries to slide forward in the sliding hole 32, but at this time, the open orifice 37A between the ring 37 and the rod 33 slides. In order to resist the outflow of the brake oil in the movement hole 32, a time delay occurs in the displacement of the piston 34. This time delay, combined with the high responsiveness of the position detection rod IIB, which is directly driven by the reaction force of the braking torque, allows the brake pressure to respond well to sudden changes in the friction coefficient μ. In addition, in this case, the cross-sectional area of the position detection rod IIB is set in advance so that the expansion of the volume of the pressure chamber 31A as the position detection rod IIB retreats brings about a sufficient brake pressure drop to maintain rotation of the tire. Ru.

On the other hand, when the anti-lock is activated, the low μ
When entering a high μ road from a road, the reaction force against the braking torque increases rapidly due to a decrease in the slip ratio, and the position detection rod I
IB is largely displaced toward the compression side. As a result, the volume reduction of the pressure chamber 3.1A functions as a pressure booster pump to immediately increase the brake pressure, and the rod 33 pushes the poppet 28 up from the seat 29, causing high pressure braking oil to flow from the mask cylinder to the brake caliper 4. further increasing brake pressure by enabling supply. In this case too,
In response to increasing brake pressure, the piston 34 moves into the sliding hole 3.
However, since the orifice 37A resists the flow of brake oil into the sliding hole 32, there is a time delay in the displacement of the piston 34, so the brake pressure increases instantaneously. Therefore, there is no fear that the braking torque will be insufficient even when entering from a low μ road to a high μ road, and the braking operation can be performed efficiently over a short distance.

Note that when the brake lever is released in the anti-lock activated state with both the pressure regulator valve 11 and the pressure cut valve 13 closed, the pressure in the mask cylinder decreases, and the relatively high pressure oil in the brake caliper 4 flows into the poppet 28. and 1
9 is pushed open with almost no resistance, and the flow returns to the mask cylinder, returning to the state before braking.

tIS4 shows the pressure regulator valve 1 using bellows 50 and 52 instead of the spool 23 and piston 34.
1 and pressure cut valve 13, the rod 25 is fixed to the poppet 19, and a check valve 51 to which the rod 33 is fixed is used in place of the poppet 28. Further, the orifice 37A is formed to pass through a plate-shaped sliding member 54 that defines the pressure chamber 31A and the outside of the bellows 52 housed inside the sliding hole 32. In this case as well, the operating principle is the same as in the first embodiment, but the bellows 52
and 54, there is no risk of brake oil leaking from the sliding holes 22 and 31, and since the seals 26 and 38 are not required, the sliding 7 riction can be expected to further improve responsiveness. .

Further, the present invention can also be applied to a brake for the rear wheel of a two-wheeled vehicle, as shown in FIG. Here, the brake caliper 4 is rotatably supported at its lower end by the axle 44 of the rear wheel,
The upper end is hingedly connected to the tip of a position detection rod IIB that freely slides and protrudes from the valve block 11A. A base end of the valve block 11A is hinged to an intermediate portion of a swing arm 43 that supports an axle 44. Furthermore, instead of Kutsushiran 9, a valve block 11A and a position detection rod 1 are added.
A spring 45 is interposed between iB and iB.

The structure of the pressure regulator valve 11 and the pressure cut valve 13 may be any of the above two embodiments. As described above, when the present invention is applied to the brakes for the rear wheels, a highly responsive anti-lock function can be obtained in exactly the same way as for the front wheels.

(Effects of the Invention) As described above, the antilock brake of the present invention opens and closes the check valve in the brake oil passage using the position detection rod that is displaced in response to the reaction force of the braking torque and the pressure responsive member that responds to the brake pressure. At the same time, since the volume within the pressure chamber is changed to increase or decrease the braking oil pressure, braking is performed with the optimum braking torque depending on the road surface condition. In addition, because it is equipped with an orifice that hydraulically regulates the displacement of the pressure-responsive member, sudden changes in braking torque can be instantaneously responded to by opening and closing the pulp and changing the volume of the pressure chamber in direct response to the displacement of the position detection rod. change the braking torque. Therefore, responsiveness to changes in road surface conditions is high and braking operations can be performed extremely efficiently.

In addition, there is no need to separately install a mechanism to detect the locked state of the tires, and braking torque can be controlled according to the braking situation with a simple configuration, resulting in lower installation costs than conventional anti-lock brakes. It can save a lot of space.

[Brief explanation of the drawing]

FIG. 1 is a side view of a main part of a front wheel of a two-wheeled vehicle showing the @1 embodiment of the present invention, FIG. 2 is a sectional view of the same valve block, and FIG. 3 is a graph showing the relationship between braking torque and slip ratio. Further, FIG. 4 is a sectional view of a valve block showing a second embodiment of the present invention, and FIG. 5 is a side view of essential parts showing application of the present invention to a rear wheel of a two-wheeled vehicle. 4... Brake caliper, IIB... Position detection rod, 12... Piping, 28... Poppet, 31A...
・Pressure chamber, 34...piston, 37A...orifice. Patent applicant Kayabae Gyo Co., Ltd. Figure 2 428-・Bobe Nodo Jl・-raitJ! J4--Goston J7A--Illifiss Figure 3 Procedure with mouth correct place (1 January 20, 1986

Claims (1)

[Claims] A position where the brake caliper is mounted so that it can be displaced according to the braking torque, a pressure chamber equipped with a check valve is provided in the middle of the path that supplies brake oil to the brake caliper, and this pressure chamber expands and contracts in conjunction with the displacement of the brake caliper. a detection rod, a pressure responsive member that is elastically supported by the position detection rod and opens and closes the check valve in response to the pressure in the pressure chamber, and a pressure responsive member that is interposed between the pressure responsive member and the pressure chamber to An anti-lock brake characterized by comprising an orifice that hydraulically regulates the displacement speed of a member.