JP2900187B2 - Motorcycle braking system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Objects of the Invention (1) Field of the Invention The present invention relates to a braking device for a motorcycle, and in particular, a pressure control valve interposed in an oil passage connected to a brake cylinder of a rear wheel. Accordingly, the present invention relates to a motorcycle braking device in which the distribution ratio of the braking force between the front wheels and the rear wheels is close to the ideal distribution characteristics.

(2) Conventional technology A conventional interlocking brake system for a motorcycle generally includes a brake cylinder that brakes a front wheel and a brake cylinder that brakes a rear wheel, and a brake hydraulic pressure generated by a master cylinder connected to a brake lever generates a brake of the front wheel. In addition to operating the brake cylinder, the brake cylinder of the front wheel and the brake cylinder of the rear wheel are operated by the brake oil pressure generated by the master cylinder connected to the brake pedal (for example, see Japanese Patent Application Laid-Open No. 55-14 / 55).
No. 0637).

(3) Problems to be Solved by the Invention By the way, the above-described conventional motorcycle braking device is a master cylinder that is operated by a brake pedal so that a distribution ratio between a front wheel braking force and a rear wheel braking force approaches an ideal distribution characteristic. A proportional valve is interposed between the brake cylinder of the rear wheel and the rear wheel, and as shown in FIG. 9A, after the braking force of the front wheel and the rear wheel reaches the point A, it is transmitted to the brake shilling of the rear wheel. It is configured such that the rate of increase in brake oil pressure decreases.

Further, the motorcycle braking device proposed in Japanese Patent Application No. 2-182926 by the present applicant uses a pressure control valve interposed in an oil passage connected to a brake cylinder of a rear wheel to form a ninth brake.
As shown in the figure, the brake hydraulic pressure transmitted to the rear wheel brake cylinder at point A is cut, and the brake hydraulic pressure transmitted to the rear wheel brake cylinder at point B is further reduced. Thereby, the distribution ratio of the braking force between the front wheels and the rear wheels can be made close to the ideal distribution characteristics.

However, even in the braking device according to the present applicant, a region slightly deviating from the ideal distribution characteristic still exists near the point A (see a hatched region in FIG. 9B).

SUMMARY OF THE INVENTION It is an object of the present invention to further improve the motorcycle braking device disclosed in Japanese Patent Application No. 2-182926, and to make the distribution ratio of the braking force between the front wheels and the rear wheels closer to the ideal distribution characteristics.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a brake cylinder for braking a front wheel, a brake cylinder for braking a rear wheel, and a brake cylinder for the brake cylinder. In a motorcycle braking device including a master cylinder that supplies a brake oil pressure so as to interlock with a brake cylinder, a pressure control valve is interposed in an oil passage connecting the master cylinder and a brake cylinder of a rear wheel, and the pressure control thereof is performed. The valve is provided with a proportional valve that reduces a rate of increase in brake hydraulic pressure transmitted to the brake cylinder, a cut valve that keeps the brake hydraulic pressure constant, and a pressure reducing valve that reduces the brake hydraulic pressure. Is slidably disposed in a valve chamber connected to an input port of the pressure control valve and is formed in a cylindrical shape. A cut valve is housed in the proportional valve so that the cut valve also functions as the valve body of the proportional valve, and an auxiliary valve body connected to the cut valve is slidably inserted coaxially through the proportional valve. A first valve spring that determines an operation start pressure of the proportional valve, and a second valve spring that determines an operation start pressure of the cut valve is connected to the auxiliary valve body, The pressure reducing valve is configured to increase a volume of an oil passage on an output port side of the pressure control valve when the pressure reducing valve is operated, and is connected to a third valve spring that determines an operation start pressure of the pressure reducing valve. When the brake oil pressure acting on the input port exceeds a first limit point, the proportional valve resists the set load of the first valve spring. When the brake valve starts to operate and its brake oil pressure exceeds a second limit point higher than the first limit point, the cut valve moves to the second limit point.
Starts operating against the set load of the valve spring, and further, when the brake oil pressure exceeds a third limit point higher than the second limit point, the pressure reducing valve responds to the set load of the third valve spring. The valves are sequentially operated in such a manner as to start operating in opposition to each other, and the pressure control valve is increased in the set load of each of the valve springs in accordance with the increase in the load on the rear cushion, whereby the sequential operation is performed. Before the determination based on the above, a correction mechanism for correcting the distribution characteristic of the rear wheel braking force is connected.

(2) Operation According to the above feature, the brake oil pressure generated by the master cylinder is directly transmitted to the front wheel brake cylinder, and is transmitted to the rear wheel brake cylinder via the pressure control valve. At this time, when the brake oil pressure generated by the master cylinder increases, the pressure control valve operates to control the brake oil pressure transmitted to the rear wheel brake cylinder. That is, with an increase in the input brake hydraulic pressure transmitted to the pressure control valve, first, the proportional valve operates to decrease the increasing rate of the output brake hydraulic pressure transmitted to the rear wheel brake cylinder, and the input brake hydraulic pressure further increases. When it increases, the cut valve operates and the output brake oil pressure becomes constant. And when the input brake oil pressure further increases,
Finally, the pressure reducing valve is operated to reduce the output brake oil pressure, and as a result, the distribution ratio between the braking force of the front wheels and the braking force of the rear wheels approaches the ideal distribution characteristic.

Before the correction mechanism is determined based on the sequential operation of the proportional valve, the cut valve, and the pressure reducing valve, the distribution characteristic of the rear wheel braking force is increased, and the distribution ratio of the rear wheel braking force is increased according to the increase in the load on the rear cushion. Even if there is a large increase in the load of the rear cushion due to two-passenger riding, etc., before and after adjusting to the increased load (that is, the distribution ratio of the rear wheel braking force is increased). The distribution characteristic of the wheel braking force can be automatically set. As a result, an optimal brake characteristic (that is, close to the ideal distribution characteristic) is always obtained in accordance with an increase in the load on the rear cushion due to two-seater riding or the like.

Furthermore, since the valve body of the proportional valve can be also used as a cut valve, the valve structure can be simplified and downsized accordingly. In addition, the operating characteristics of the proportional valve, the cut valve, and the pressure reducing valve can be freely set by appropriately selecting the valve springs separately and independently connected to the respective valves, so that the degree of design freedom is increased accordingly. In addition, since the degree of freedom in selecting each valve increases, for example, if a proportional valve is used for a four-wheeled vehicle, cost reduction can be achieved by mass production effect.

(3) Example Hereinafter, an example of the present invention will be described with reference to the drawings.

1 to 6 show a first embodiment of the present invention.
1 is an overall plan view of a motorcycle provided with the braking device, FIG. 2 is an enlarged sectional view of a main part of the braking device, FIG. 3 is a detailed view of a mechanical servo mechanism, and FIG. 4 is a rear fork of the motorcycle. FIG. 5 is a view in the direction of arrow V in FIG. 4, and FIG. 6 is a graph showing the braking characteristics thereof.

As shown in FIGS. 1 and 2, the motorcycle V includes a brake lever L provided on a steering wheel and a brake pedal P provided on a vehicle body frame. Left and right brake cylinders Bc _f1, Bc _fr is provided on the front wheels Wf, each of the brake cylinders Bc _fr, Bc _fl comprises two pot front pot P ₁ and the rear pot P _2. The first master cylinder Mc ₁ operated by the brake lever L is directly connected to the rear pot P ₂ of the left and right brake cylinders Bc _fl and Bc _fr , and the second master cylinder Mc ₂ operated by the brake pedal P is the two brake cylinders Bc _fl, is connected directly to the front pots P ₁ of Bc _fr.

A mechanical servo mechanism Ms connected to the second master cylinder Mc ₂ is mounted on the brake cylinder Bc _fr on the right side of the front wheel Wf, and the brake hydraulic pressure generated by the mechanical servo mechanism Ms is supplied to the rear wheel Wr via the pressure control valve Cv. It is transmitted to the pot P ₀ of the brake cylinder Bc _r. Further, the pressure control valve Cv includes:
A preload adjuster Pa provided on the rear cushion C is connected to change the braking characteristics according to the number of occupants.

As shown in FIG. 3, the mechanical servo mechanism Ms
It is integrally provided at the outer end of a right brake cylinder Bc _fr pivotally supported by a pin 3 on a bracket 2 fixed to a front fork 1 of Wf. A piston 7 provided with a primary cup seal 6 having a lip on its outer periphery slides on a cylinder portion 5 formed on a casing 4 of the mechanical servo mechanism Ms.
Is connected to the bracket 9 fixedly mounted. Oil chamber 11 housing the spring 10 return between the piston 7 and the cylinder unit 5 is formed, the brake cylinder Bc _r of the rear wheels Wr output port 12 formed in the oil chamber 11 through the pressure control valve Cv Connected to. Wherein the casing 4 is formed an input port 13 connected to the second master cylinder Mc _2, the input port 13 communicates with the front pot P ₁ of the brake cylinder Bc _fr via the oil passage 14. An auxiliary oil chamber 17 communicating with the oil chamber 11 via a supply port 15 and a relief port 16 is formed in the casing 4. The auxiliary oil chamber 17 and the front pot P ₁ are connected to an oil passage 18.
Communicate through. The first master cylinder Mc ₁ is connected to the rear pot P ₂ through the input port 19 and the oil passage 20 formed in the casing 4. Reference numerals 21 to 23 denote air release plugs for discharging air when the brake oil is filled.

Next, the structure of the pressure control valve Cv will be described in detail with reference to FIG. The pressure control valve Cv is the output port 12 of the mechanical servo mechanism Ms.
Input port 31 connected to the brake cylinder Bc of the rear wheel Wr
and an output port 32 connected to the pot P ₀ of _r. A valve chamber 33 communicating with the input port 31 and an oil chamber 34 communicating with the output port 32 communicate with each other via an oil passage 35, and a cylindrical proportional valve 36 is disposed inside the valve chamber 33 so as to be vertically movable. Have been. The inner chamber 36 ₂ of the proportional valve 36 which communicates with the input port 31 via the oil hole 36 _1, the valve spring 3
A cut valve 38 urged in the valve closing direction at 7 is provided. When the cut valve 38 is in the illustrated open position, the input port 31 communicates with the output port 32 via the oil hole 36 ₁ , the inner chamber 36 ₂ , the outer periphery of the cut valve 38, the oil passage 35, and the oil chamber 34. I do. A pressure control valve Cv is further pressure reducing valve 39, with its leading end portion of the pressure reducing valve 39 faces the oil chamber 34, the stepped portion 39 ₁ is the valve chamber 3 via the oil passage 40 formed in an intermediate portion
It is arranged in a valve chamber 41 communicating with 3.

A spring seat 44 urged downward by a return spring 43 is provided inside a spring chamber 42 connected to a lower portion of the valve chamber 33, and a valve spring is provided between the spring seat 44 and the proportional valve 36. 45 will be reduced. Inner chamber of proportional valve 36
An auxiliary valve element 46 is slidably fitted to the element 36 ₂ , and the lower end of the auxiliary valve element 46 is
And an upper end thereof supports a valve spring 37 for urging the cut valve 38. A load sensing valve 47 is supported at a lower part of the spring chamber 42 so as to be vertically movable, an upper end thereof abuts on a lower surface of the spring seat 44, and a lower end thereof communicates with a preload adjuster Pa described later via an input port 48. It projects into the oil chamber 49. On the other hand, a spring chamber 50 is formed at a lower portion of the pressure reducing valve 39, and a spring seat 52 urged downward by a return spring 51 is provided therein, and supports the lower end of the spring seat 52 and the pressure reducing valve 39. Between the spring seat 53, a valve spring 54 is contracted. The upper end of the load sensing valve 55 supported vertically below the spring chamber 50 is in contact with the lower surface of the spring seat 52, and the lower end protrudes into the oil chamber 49. The cut valve 38 is provided above the valve chamber 33.
An auxiliary valve body 56 which is in contact with the upper end of the valve and forcibly opens the cut valve 38 is disposed to be vertically movable. The upper end of the auxiliary valve body 56 contacts a spring seat 58 disposed inside the spring chamber 57,
The spring seat 60 urged upward by the spring seat 58 and the return spring 59
Between them, a valve spring 61 is contracted. A load sensing valve 62 is supported on the upper part of the spring chamber 57 so as to be movable up and down, a lower end thereof abuts on an upper surface of the spring seat 60, and an upper end thereof projects into an input port 63 communicating with a preload adjuster Pa.

Preload adjuster provided on rear cushion C
Pa is provided with an annular piston 74 slidably movable up and down in an annular space formed by a cylindrical body 72 fixed to an upper outer periphery of an oil damper 71 and a cylinder member 73 having an open lower surface. An upper end of a buffer spring 76 of a rear cushion C is supported by a retainer 75 mounted below the annular piston 74, and a boot 77 made of an elastic material is provided between the retainer 75 and the cylinder member 73.
Is attached. An oil chamber 78 defined by the cylinder 72, the cylinder member 73, and the annular piston 74 is connected to input ports 48, 63 of the pressure control valve Cv via an output port 79.

As shown in FIGS. 4 and 5, a front end of a rear fork 83 is pivotally supported at the rear of a body frame 81 of the motorcycle V via a pivot 82 so as to be vertically swingable. An upper end and a lower end of the rear cushion C are provided between a bracket 84 provided on the upper surface of the body frame 81 and an L-shaped first link 86 pivotally supported at one end to the bracket 85 provided on the lower surface of the rear fork 83. The first link 86 is connected to a bracket 87 provided on the lower surface of the vehicle body frame 81 and a second link
Connected at 88. Therefore, when the rear fork 83 swings up and down around the pivot 82, the load is buffered by the expansion and contraction of the rear cushion C.

Axle 89 is positioned adjustably fixed front and rear elongated hole 83 ₃ formed at the rear end of the bifurcated rear fork 83, a sprocket 91 fixed to the left side surface of the hub 90 of the rear wheel Wr which is supported by the axles 89 Is driven by a driving chain 92. The hub
The right side of the 90 fixed brake disc 93, the brake disc 93 is braked is pinched by the brake cylinder Bc _r mounted on top of the brake cylinder support member 94 provided at the rear end of the rear fork 83 . The lower end of the brake cylinder support member 94 while being pivoted to the axle 89, projections 94 ₁ provided at its front end engages the elongated hole 83 ₂ of the bracket 83 ₁ projecting from the upper surface of the rear fork 83, after Wheel Wr
By adjusting the longitudinal position of the brake cylinder Bc _r be the rear wheels Wr
It is configured to move in the front-back direction integrally with the camera.

The pressure control valve Cv is mounted on the upper surface of a support plate 95 that connects the front left and right of the rear fork 83. The pressure control valve Cv is disposed between the rear cushion C and the rear wheel Wr in a side view, and is further disposed so as to be located within the width of the rear fork 83 in a plan view. Pressure control valve Cv and the brake cylinder Bc _r are connected by flare pipe 97 made of metal is fixed by the supporting member 96 along the upper surface of the rear fork 83. Also, the pressure control valve Cv
The mechanical servo mechanism Ms is connected to the upper surface of the rear fork 83 by a flare pipe 99 fixed by a support member 98. Further, the preload adjuster Pa and the pressure control valve Cv provided at the upper end of the rear cushion C are connected to two rubber pipes 100 and 10.
Connected by one. Thus, when the rear fork 83 swings, the relative movement between the preload adjuster Pa and the pressure control valve Cv is absorbed by the deformation of the rubber pipes 100 and 101.

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

When the brake lever L is operated, the first master cylinder
Brake cylinder Bc _fl of the left and right brake hydraulic pressure of the front wheel Wf of Mc ₁ occurs, is transmitted to the rear pot P ₂ of Bc _fr front wheel Wf
Brake. At this time, as apparent from FIG. 3, the brake cylinder Bc _fr swings around the pin 3 in the direction of the arrow a, so that the casing 4 of the mechanical servo mechanism Ms integrally provided above the brake cylinder Bc _fr. Move in the same direction, and as a result, the piston 7 supported on the front fork 1 via the rod 8 advances inside the cylinder portion 5 against the return spring 10. When the primary cup seal 6 attached to the piston 7 passes through the relief port 16,
Oil chamber 11 secondary hydraulic braking pressure is generated in, the brake hydraulic pressure is transmitted to the brake cylinder Bc _r of the rear wheel Wr through the pressure control valve Cv from the output port 12.

Also, when operating the brake pedal P, the brake hydraulic pressure second master cylinder Mc ₂ is generated, the left and right brake cylinders Bc _fl of the front wheels Wf, to brake the front wheel Wf is transmitted to the front pot P ₁ of Bc _fr. At this time, as in the case where the brake lever L is operated, the mechanical servo mechanism Ms operates and the rear wheel Wr
Secondary hydraulic braking pressure is transmitted to the brake cylinder Bc _r. However, the secondary brake oil pressure is generated as described above because the oil pressure inside the oil chamber 11 of the mechanical servo mechanism Ms is
Only if greater than the hydraulic pressure transmitted from the second master cylinder Mc ₂ to the auxiliary oil chamber 17 of the mechanical servo mechanism Ms. That is, only when the oil pressure transmitted to the auxiliary oil chamber 17 increases beyond the oil pressure inside the oil chamber 11, the lip of the primary cup seal 6 attached to the piston 7 is compressed and the oil pressure in the auxiliary oil chamber 17 is reduced. Is transmitted directly to the oil chamber 11. Therefore, secondary hydraulic braking pressure mechanical servo mechanism Ms is generated, is greater than the hydraulic braking pressure second master cylinder Mc ₂ occurs, the brake hydraulic pressure of the mechanical servo mechanism Ms is transmitted to the pressure control valve Cv, conversely 2nd master cylinder Mc
If towards the brake _hydraulic pressure ₂ occurs is large, the brake hydraulic pressure to which the second master cylinder Mc ₂ are generated is transmitted to the pressure control valve Cv.

Now, as described above, the input port 31 of the pressure control valve Cv
During Added braking oil pressure is low, the oil hole 36 ₁ and the inner chamber 36 ₂ of the brake hydraulic pressure proportional valve 36,
The outer periphery of the cut valve 38, the oil passage 35, is transmitted to the brake cylinder Bc _r of the rear wheels Wr via the oil chamber 34 and the output port 32,. At this time, since the braking force of the front wheel Wf and the braking force of the rear wheel Wr both increase in accordance with the operation amount of the brake lever L or the brake pedal P, their distribution characteristics are O in FIG.
It is a straight line connecting point A and point A.

When the brake oil pressure transmitted to the input port 31 of the pressure control valve Cv further increases and the braking force of the rear wheel Wr reaches the point A in FIG. 6, the proportional hydraulic valve is actuated by the brake oil pressure acting on the upper surface of the proportional valve 36. 36 is a valve spring 45
Descends against the set load. As a result, the proportional valve 36 comes into close contact with the cut valve 38 and the input port
Although the communication between 31 and output port 32 is temporarily interrupted, if the brake hydraulic pressure transmitted to input port 31 further increases,
Proportional valve 36 is pushed up by increasing the pressure in the inner chamber 36 ₂ of the proportional valve 36, an input port 31
And the output port 32 communicate again. In this way, by proportional valve 36 with an increase of the brake hydraulic pressure is vibrated up and down, because the gap between the proportional valve 36 and the cut valve 38 is intermittently opened and closed, it is transmitted to the brake cylinder Bc _r The rate of increase in brake oil pressure decreases. As a result, the rate of increase in the braking force of the rear wheel Wr decreases at the point A in FIG.

When the brake oil pressure transmitted to the input port 31 of the pressure control valve Cv further increases and the braking force of the rear wheel Wr reaches the point B in FIG. 6, the auxiliary valve body 56 resists the set load of the valve spring 61. As a result, the cut valve 38 urged by the valve spring 37 rises and comes into close contact with the proportional valve 36. As a result, the communication between the input port 31 and the output port 32 is completely cut off.
Hydraulic braking pressure transmitted to bc _r is kept constant.

When the brake oil pressure transmitted to the input port 31 of the pressure control valve Cv further increases and the braking force of the rear wheel Wr reaches the point C in FIG. 6, the brake oil pressure is transferred to the oil chamber 41 via the oil passage 40. The transmitted pressure lowers the pressure reducing valve 39 against the set load of the valve spring 54. As a result, since the volume of the oil chamber 34 tip is lowered the pressure reducing valve 39 is increased, the hydraulic braking pressure transmitted to the brake cylinder Bc _r decreases.

And Thus, hydraulic braking pressure transmitted to the brake cylinder Bc _r of the rear wheel Wr by the action of the pressure control valve Cv, i.e. the rear wheel W
The braking force of r changes in four stages, the braking force of the front wheel Wf and the rear wheel Wr
The distribution ratio of the braking force changes like OABCD in FIG. 6, and a characteristic very close to the ideal distribution characteristic can be obtained.

Now, when the load applied to the rear cushion C increases due to two persons riding the motorcycle V, the annular piston 74 supporting the upper end of the buffer spring 76 via the retainer 75 receives an upward load, and The generated oil pressure increases.
The hydraulic pressure generated by the preload adjuster Pa is transmitted to the oil chamber 49 of the pressure control valve Cv through an output port 79 and an input port 48, and is transmitted to two load sensing valves 47 and 55.
Push up. As a result, the set load of the valve spring 45 for urging the proportional valve 36 and the valve spring 54 for urging the pressure reducing valve 39 increases. Similarly, preload adjuster
The hydraulic pressure at which Pa is generated is transmitted to the input port 63 to push down the load sensing valve 62 and increase the set load of the valve spring 61 for urging the auxiliary valve body 56.

As described above, when the set load of the valve springs 42, 53, 61 for urging the proportional valve 36, the cut valve 38, and the pressure reducing valve 39 during the two-passenger riding increases, the three valves 36, 38, 39 Operates, that is, the positions of points A to C in FIG. 6 move rightward. Thereby, the distribution characteristic of the braking force between the front wheel Wf and the rear wheel Wr is changed from the point A 'to the point D'.
The characteristic changes like a dashed line passing through the points, and the ratio of the braking force of the rear wheel Wr is increased so as to conform to the ideal distribution characteristic when two passengers are riding, whereby optimum characteristics can be obtained.

Thus, the preload adjuster Pa, the load sensing valves 47, 55, and 62 and the oil passage therebetween form a correction mechanism M of the present invention in cooperation with each other.

FIG. 7 shows a second embodiment of the present invention, in which a mechanical servo mechanism Ms is not used in the braking device of this embodiment. That is, the left and right brake cylinders of the first master cylinder Mc ₁ is a front wheel Wf operated by the brake lever L Bc
_fl , Bc _fr The second master cylinder Mc ₂ directly connected to the front pot P _{1 of fr} and operated by the brake pedal P
There the two brake cylinders Bc _fl, is connected directly to the rear pot P ₂ of Bc _fr. Then, the second master cylinder Mc ₂
Brake cylinder Bc _r of the rear wheel Wr through the pressure control valve Cv is
Connected to.

FIG. 8 shows a third embodiment of the present invention which does not use the mechanical servo mechanism Ms. In this embodiment, the first master cylinder Mc ₁ is connected directly to the front and rear pots P _1, P ₂ of the right brake cylinder Bc _fr of the front wheels Wf operated by the brake lever L. The front and rear pots P _1, P of the second master cylinder Mc ₂ are front wheels Wf left brake cylinder Bc _fl actuated by the brake pedal P
While being directly connected to the _2, it is connected to the brake cylinder Bc _r of the rear wheel Wr through the pressure control valve Cv.

And Thus, the in the second and third embodiments, when at the same time braking the front wheels Wf and rear wheels Wr by operating the brake pedal P, the brake cylinder Bc _r of the rear wheel Wr by the pressure control valve Cv
By controlling the brake hydraulic pressure transmitted to the front wheels
The distribution ratio of the braking force between Wf and the rear wheel Wr can be made closer to the ideal distribution characteristic.

As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to the above embodiments, and various small design changes can be made without departing from the present invention described in the claims. Is possible.

C. Effects of the Invention As described above, according to the present invention, a pressure control valve having a proportional valve, a cut valve, and a pressure reducing valve is interposed between a master cylinder and a rear wheel brake cylinder, and transmitted to the pressure control valve. As the proportional valve, the cut valve and the pressure reducing valve are sequentially operated with the increase in the brake oil pressure, the brake oil pressure transmitted to the brake cylinder increases, gradually increases,
The distribution ratio between the braking force of the front wheels and the braking force of the rear wheels can be made closer to the ideal distribution characteristic by being controlled in four stages of holding and decreasing.

In addition, the pressure control valve has a distribution characteristic of the rear wheel braking force, which is determined based on the sequential operation of the proportional valve, the cut valve, and the pressure reducing valve, according to an increase in the load on the rear cushion. A correction mechanism is connected to increase the distribution ratio of the rear cushion, so that even if there is a significant increase in the load of the rear cushion due to two-seater riding or the like, the rear cushion is adapted to the increase in the load (that is, the rear wheel braking force). Before the distribution ratio is corrected to the increasing side, the distribution characteristic of the rear wheel braking force can be automatically set. Therefore, it is always optimal (that is, in accordance with the increase in the load on the rear cushion due to the two-passenger riding). Brake characteristics (close to ideal distribution characteristics) can be obtained.

Further, since the cut valve can be used also as the valve body of the proportional valve, the valve structure can be simplified and downsized accordingly. In addition, since the operating characteristics of the proportional valve, the cut valve, and the pressure reducing valve can be freely set by appropriately selecting a valve spring separately and independently connected to each of the valves,
As a result, the degree of freedom in design increases, and the degree of freedom in selecting each valve also increases.

[Brief description of the drawings]

1 to 6 show a first embodiment of the present invention. FIG. 1 is an overall plan view of a motorcycle provided with the braking device.
FIG. 2 is an enlarged sectional view of a main part of the braking device, FIG. 3 is a detailed view of a mechanical servo mechanism, FIG. 4 is an enlarged side view of a rear fork portion of a motorcycle, and FIG. FIG. 6 is a graph showing the braking characteristics thereof, FIG. 7 is an enlarged sectional view of a main part of the braking device according to the second embodiment of the present invention, and FIG. 8 is a diagram of the braking device according to the third embodiment of the present invention. Main section enlarged sectional view, No.
9A and 9B are graphs showing the braking characteristics of the conventional braking device. Bc _fl , Bc _fr ; Bc _r …… Brake cylinder, C …… Rear cushion, Cv …… Pressure control valve, M …… Correction mechanism, Mc ₁ , Mc ₂
…… Master cylinder, Wf …… Front wheel, Wr …… Rear wheel, 31 ……
Input port, 32 Output port, 33 Valve chamber, 36 Proportional valve, 38 Cut valve, 39 Pressure reducing valve, 45 First valve spring, 54 Third valve spring ,
56 ... Auxiliary valve element, 61 ... Second valve spring,

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yukimasa Nishimoto 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Technical Research Institute Co., Ltd. (56) References JP-A-54-8344 (JP, A) JP-A Sho 55-164549 (JP, A) JP-A-57-30650 (JP, A) JP-A-58-22747 (JP, A) JP-A-61-285165 (JP, A) U) (58) Fields investigated (Int.Cl. ⁶ , DB name) B60T 8/26 B62L 3/00-3/08

Claims (1)

(57) [Claims] A brake cylinder (Bc _fl , Bc _fr ) for braking a front wheel (Wf), a brake cylinder (Bc _r ) for braking a rear wheel (Wr), and the brake cylinder (Bc _fl , Bc _fr ; B)
The braking device for a motorcycle that includes a master cylinder (Mc _1, Mc ₂₎ for supplying a brake hydraulic pressure so as to interlock it, etc. c _r), said master cylinder (Mc _1, Mc ₂₎ and rear wheels ( Wr) to the oil passage connecting the brake cylinder (Bc _R ) to the pressure control valve (C
v) is interposed, on its pressure control valve (Cv), and proportional valve (36) to reduce the rate of increase in hydraulic braking pressure transmitted to the brake cylinder (Bc _R), keeping the brake hydraulic pressure constant A cut valve (38) and a pressure reducing valve (39) for reducing the brake oil pressure are provided, and the proportional valve (36) is connected to a valve chamber (33) connected to an input port (31) of the pressure control valve (Cv). ) Is formed so as to be slidable and formed in a cylindrical shape, and a cut valve (38) is provided in the proportional valve (36) so that the cut valve (38) also serves as a valve element of the proportional valve (36). ) Is contained,
An auxiliary valve body (56) connected to the cut valve (38) is coaxially and slidably inserted through the proportional valve (36). The first proportional valve (36) determines the operation start pressure of the proportional valve (36). A second valve spring (61) for determining an operation start pressure of the cut valve (38) is connected to the valve spring (45) and the auxiliary valve body (56), respectively. ) Is configured to increase the volume of the oil passage on the output port (32) side of the pressure control valve (Cv) at the time of its operation, and to determine the operation start pressure of the pressure reducing valve (39). When the brake oil pressure acting on the input port (31) exceeds a first limit point, the proportional valve (36) is connected to the set load of the first valve spring (45). Starts to work, and then the brake oil pressure When a second limit point higher than the first limit point is exceeded, the cut valve (38) starts operating against the set load of the second valve spring (61), and further, the brake oil pressure is reduced to the second limit value. When a third limit point, which is higher than the third limit point, is exceeded, the pressure reducing valve (39) starts operating against the set load of the third valve spring (54). , 39) are sequentially performed. The pressure control valve (Cv) increases the set load of each of the valve springs (45, 61, 54) in accordance with the increase in the load of the rear cushion (C), A braking device for a motorcycle, wherein a correction mechanism (M) for correcting a distribution characteristic of a rear wheel braking force is connected before being determined based on the sequential operation.