JPH0239415B2 - JIDONIRINSHANOSEIDOSOCHOMASUTASHIRINDA - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a master cylinder used in a braking device for a motorcycle that includes a manual first brake operating member and a foot-operated second brake operating member.

Conventional braking devices for general motorcycles have come to operate the front wheel brake, which applies braking force to the front wheel, and the rear wheel brake, which applies braking force to the rear wheel, separately by operating first and second brake operation members. However, it is preferable if both the front and rear wheel brakes can be actuated by a braking input from either the first or second braking operating member, since this simplifies the braking operation. In addition, in such a case, either the front or rear wheel brakes will be operated in such a way that when the braking input is excessive, the braking force on one wheel will be automatically relaxed and restored to prevent that wheel from locking up. On the other hand, it is desirable for the braking performance of a motorcycle to be able to freely adjust the braking force for the other wheel by adjusting the braking input.

Furthermore, when this type of master cylinder is configured in tandem by sliding the first and second braking pistons back and forth in the cylinder body, both pistons can be connected to a relief port that opens into the hydraulic chamber and a supply port that opens to the replenishment oil chamber. In order to position the pistons correctly, a stopper must be provided on the cylinder body to restrict the retraction limit of both pistons. In this case, for the second brake piston located at the rear, a stopper can be easily formed by fitting a stop ring to the rear end of the cylinder hole, but for the first brake piston located at the front, a stopper can be easily formed on the peripheral wall of the cylinder body. Since a screw hole is formed in the cylinder body and a stopper screw is screwed therein, the number of machining steps is large, and it is not preferable to form a screw hole in the cylinder body which requires oil tightness.

It is an object of the present invention to provide a master cylinder which can satisfy the above-mentioned requirements and eliminate the above-mentioned problems, and which is small in size and simple in structure. a first cylinder hole and a second cylinder hole;
The first and second brake pistons are slid back and forth in the cylinder hole to define a first brake hydraulic chamber between the partition wall and the first brake piston in which hydraulic pressure is generated by the advancement of the first brake piston, and the first and second brake pistons A second brake hydraulic chamber is defined between the two brake pistons in which hydraulic pressure is generated by the advancement of the second brake piston, and one of the first and second output ports provided in the first and second brake hydraulic chambers, respectively, is connected to the front wheel. a first pressure receiving part that communicates with the brake and the rear wheel brake with the other, and causes the second brake piston to advance the second brake piston in response to braking input from the manual first brake operation member; a second brake piston that advances the second brake piston in response to a brake input from the second brake operation member;
A control piston is slid into the second cylinder hole to form a control hydraulic chamber on the front side of the control piston to which control hydraulic pressure can be applied from a hydraulic source in a timely manner, and the brake piston is connected to the first brake piston. The first brake piston is connected via a piston rod that protrudes from the front surface and slides through the partition wall, and is provided with a stopper at the tip of the piston rod that comes into contact with the front surface of the partition wall and restricts the backward limit of the first brake piston. shall be.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In Figs. 1 and 2, a motorcycle has a brake lever 1, which is a first braking operation member, on a steering handle H, and a front part operated by the brake lever 1. A master cylinder Mf is provided, and a brake pedal 2, which is a second braking operation member, is provided at the bottom of the vehicle body F.
and can be actuated by braking input from either the brake pedal 2 or the brake lever 1.
The rear master cylinder Mr, which is the master cylinder of the present invention, is provided. The input from the brake lever 1 to the rear master cylinder Mr is given as the output hydraulic pressure of the front master cylinder Mf, and the input from the brake pedal 2 to the rear master cylinder Mr is mechanically transmitted. will be described later.

The rear master cylinder Mr is connected via an oil passage 4 to a pair of left and right hydraulic front wheel brakes Bf for braking the front wheels Wf, and is also connected to a single hydraulic rear wheel brake Bf for braking the rear wheels Wr. It is connected via an oil passage 5, and a known proportional pressure reducing valve V is interposed in the oil passage 5.

A horizontally opposed engine E is mounted on the vehicle body F at the front of the motorcycle and between the rear wheels Wf and Wr.
An anti-lock device that automatically reduces and recovers the braking force of only the front wheel brake Bf by controlling the operation of Mr.
Al is placed. A control signal to the anti-lock device Al is generated by a speed sensor S provided on the front wheel Wf, and is sent to the anti-lock device Al via a signal processing device C.

The configuration of each of the above parts will be further explained with reference to FIGS. 3 and 4.

The front master cylinder Mf is configured in a known single type. That is, one piston 8 operated by the brake lever 1 is slid into the cylinder hole 7 of the cylinder body 6, and the piston 8 is connected to the output port 10 of the hydraulic chamber 9 defined in the front part of the cylinder hole 7. Oil passage 11 connected to rear master cylinder Mr
is connected. Therefore, when the brake lever 1 is actuated to advance the piston 8, hydraulic pressure is generated in the hydraulic chamber 9, and the hydraulic pressure is output from the output port 10 and input to the rear master cylinder Mr.
The cylinder body 6 is integrally equipped with a reservoir 12 that can supply hydraulic oil to the hydraulic chamber 9.

The rear master cylinder Mr is constructed in a tandem type, particularly as shown in FIG. That is, the cylinder body 13 has a first cylinder hole 14 at the rear and a second cylinder hole at the front that are lined up coaxially with the fixed partition wall 16 in between.
A cylinder hole 39 is formed in the first cylinder hole 14, and the first and second brake pistons 15 ₁ ,
15 ₂ are slid together in front and back series (in the figure, vertically in series), and in the first cylinder hole 14, the first brake piston 15 1 and the fixed partition wall 16 have a first brake piston 15 ₁ and a fixed partition wall 16 between them.
A braking hydraulic chamber 17 ₁ is defined, and both pistons 15
₁ and 15 ₂ define a second brake hydraulic chamber 17 ₂ between them. The first braking hydraulic chamber 17 ₁ has a first output port 18 ₁ and the second braking hydraulic chamber 17 ₂ has a second output port 18 ₂ opening in the side wall.
An oil passage 4 connected to the front wheel brake Bf is connected to the first output port 18 ₁ , and an oil passage 5 connected to the rear wheel brake Br is connected to the second output port 18 ₂ .

The second brake piston 15 ₂ is connected to the first cylinder hole 1
Sleeve 1 fitted and fixed to the lower end opening of 4
The piston rod _152a is connected to the brake pedal ₂ via a push rod 20, and when the brake pedal 2 is depressed, the push rod is activated. 20, the second brake piston ₁₅₂ can be pushed forward (upward in the figure). 21 is a return spring for the brake pedal 2, and 22 is a stopper bolt for regulating the backward limit of the pedal 2, which is screwed onto a bracket 23 extending from the vehicle body F so that the backward limit of the pedal 2 can be adjusted. .

Further, in the first cylinder hole 14, the second brake piston ₁₅₂ and the sleeve 19 define a hydraulic chamber 24 between them, and an input port 25 opening on one side of the chamber 24 is connected to the front master cylinder. When the oil passage 11 connected to Mf is connected and hydraulic pressure is applied to the hydraulic chamber 24 from the input port 25, the second brake piston ₁₅₂ can also be pushed forward by the hydraulic pressure. Therefore, the hydraulic chamber 24
The rear surface of the second brake piston 15 ₂ facing the front side constitutes a first pressure receiving portion, and the piston rod 15 ₂ a constitutes a second pressure receiving portion.

The first and second brake hydraulic chambers 17 ₁ and 17 ₂ have a
and first and second return springs 26 ₁ and 26 ₂ that bias the second brake pistons 15 ₁ and 12 ₂ in the backward direction, that is, downward, respectively, are housed, and at this time, the set load of the second return spring 26 ₂ is the first return spring 2
6 It is set smaller than that of ₁ . In order to restrict the retraction limit of the first braking piston 15 ₁ , a circlip-shaped piston rod 15 ₁ a that protrudes from the front surface of the piston 15 ₁ and slidably passes through the partition wall 16 has a circlip shape that abuts the upper surface of the partition wall 16 . The stopper 27 is locked. Also, the second brake piston 15
In order to restrict the retraction limit of the sleeve ₁₉ , a circlip-shaped stopper 28 that comes into contact with the upper end surface of the sleeve 19 is used.
is locked to the piston rod _152a of the piston ₁₅₂ .

The second return spring 26 ₂ is the second brake piston 15 ₂
Fixed seat plate 30 fixed to the upper end of the board with bolts 29
and a movable seat plate 31 that can slide on the bolt 29 within a limited stroke range. When the brake pistons 15 ₁ , 15 ₂ are located at the backward limit, the first brake piston 15
substantially abuts the lower end of ₁ .

The first and second braking pistons 15 ₁ , 15 ₂ are provided with piston cups 32 ₁ , 32 ₂ on each front surface, and have a small diameter intermediate portion and have replenishment oil chambers 33 ₁ , 33 ₂ formed on their outer peripheries, respectively. , oil supply holes 34 ₁ , 34 ₂ are provided in each of the brake pistons 15 ₁ , 15 ₂ to communicate the oil chambers 33 ₁ , 33 ₂ to the backs of the piston cups 32 ₁ , 32 ₂ , respectively.

An oil passage 36 communicating with an oil passage 35 connected to the reservoir R is bored in the cylinder body 13 in parallel with the first and second cylinder holes 14 and 39, and both brake pistons 15 ₁ and 15 ₂ are connected to the stopper 27. , 28 and open into the first and second brake hydraulic chambers 17 ₁ , 17 _{2 ,} respectively, immediately before the piston cups 32 ₁ , 32 ₂ when the piston cups 32 ₁ , 32 ₂ are at the rearward limit; Supply ports 38 ₁ , 38 ₂ that are always open to the replenishment oil chambers 33 ₁ , 33 ₂ communicate with the oil passage 36 .

The second cylinder hole 39 is formed in the cylinder cap 13a constituting the front end of the cylinder body 13. A control piston 40 having a piston cup 41 on the front surface is slid into the cylinder hole 39, and the control piston 40 is slidably connected to the cylinder cap 13a. First brake piston 15 ₁
of the piston rod _151a . The control piston 40 divides the inside of the second cylinder hole 39 into a control oil pressure chamber 42 at the front and a replenishment oil chamber 43 at the rear, and a return spring 44 contracted in the control oil pressure chamber 42.
It is normally held at the retraction limit where it abuts against the partition wall 16. The replenishment oil chamber 43 is the replenishment oil chamber 33 ₁ , 33 ₂
Similarly, it communicates with the reservoir R via the oil passage 35,
An oil supply hole 45 is drilled in the control piston 40, which communicates the chamber 43 with the back side of the piston cup 41. In addition, 46 and 47 in FIG. 4 are air bleeders.

The anti-lock device Al includes a pair of normally-closed electromagnetic control valves 48 and 49 that control the operation of the control piston 40, a pressure accumulator Ac as a hydraulic pressure source that stores the working pressure of the control piston 40, and this pressure accumulator. It is equipped with a hydraulic pump P that supplies pressure oil to the container Ac. The hydraulic pump P is driven by the engine E. The normally closed control valve 48 connects the hydraulic pump P and accumulator Ac with the control hydraulic chamber 42, and the normally open control valve 49 connects the reservoir R and the control hydraulic chamber 42. The oil passages 51 are respectively interposed. In addition, 52, 53, 54 in FIG. 3 are oil filters provided before and after the control valves 48, 49,
55 is an oil filter provided immediately after the discharge port 56 in the hydraulic pump P, and 57 is the hydraulic pump P.
This is an oil passage that communicates the suction port 58 of the reservoir R with the reservoir R.

Next, the operation of this embodiment will be explained.

First, in FIGS. 3 and 4, if the front master cylinder Mf is actuated by the brake lever 1,
The hydraulic pressure generated in the hydraulic chamber 9 is inputted from the input port 25 to the hydraulic chamber 24 of the rear master cylinder Mr through the oil passage 11, and the second brake piston ₁₅₂ is pushed in the forward direction by the hydraulic pressure, and the reaction force is supported by the sleeve 19 and is not transmitted to the push rod 20.

Furthermore, when the brake pedal 2 is depressed, the pedal force is mechanically input to the second brake piston 15 ₂ via the push rod 20, thereby similarly pushing the second brake piston 15 ₂ in the forward direction.
Along with this, the hydraulic oil in the reservoir 12 of the front master cylinder Mf is simply sucked into the hydraulic chamber 24 whose volume increases through the hydraulic chamber 9 and the oil passage 11.
No reaction force acts on the brake lever 1.

Therefore, when the brake lever 1 and the brake pedal 2 are operated simultaneously, the sum of the pressing force due to the output hydraulic pressure of the front master cylinder Mf and the pressing force due to the push rod 20 is applied to the second brake piston ₁₅₂ as a braking input. become.

Then, when the second brake piston 15 ₂ receives the braking input as described above, the first and second brake pistons 15 ₁ , 15 ₂ are moved by the first and second return springs 26 ₁ ,
The piston cups 32 ₁ , 32 2 move forward while compressing the piston cups 32 ₁ , 32 ₂ into the relief ports 37 ₁ , 3 .
7 ₂ and then each brake piston 15 ₁ , 15 ₂
The first and second brake hydraulic chambers 17 ₁ ,
Hydraulic pressure is generated in the first brake hydraulic chamber ₁₇₂ , and the hydraulic pressure generated in the first brake hydraulic pressure chamber ₁₇₁ is transmitted from the first output port ₁₈₁ to the front wheel brake Bf via the oil passage 4 to operate it.
The hydraulic pressure generated in the second brake hydraulic pressure chamber ₁₇₂ is transmitted from the second output port ₁₈₂ through the oil passage 5 to the rear wheel brake Br.
Braking force is applied to the front and rear wheels Wf and Wr, respectively.

By the way, as mentioned above, the set load of the second return spring 26 ₂ is set smaller than that of the first return spring 26 ₁ , so when the second brake piston 15 ₂ initially moves, the first brake piston 15 ₁ does not move forward. First, the second return spring 26 ₂ is compressed, and hydraulic pressure is first generated in the second brake hydraulic chamber 17 ₂ . and,
After the oil pressure reaches a certain value _p1 , the first return spring 2
6 ₁ is compressed, the first brake piston 15 ₁ starts moving forward, and hydraulic pressure is generated in the first brake hydraulic chamber 17 ₁ .
Further, since a known proportional pressure reducing valve V is provided in the oil passage 5 between the output port 18 ₂ of the second brake hydraulic pressure chamber 17 ₂ and the rear wheel brake Br, the second output port 18
When the output oil pressure of _{No. 2} rises to a predetermined value _p2 or more, the output oil pressure is reduced at a fixed ratio by the action of the proportional pressure reducing valve V and transmitted to the rear wheel brake Br. On the other hand, since the oil passage 4 between the output port 18 ₁ of the first brake hydraulic pressure chamber 17 ₁ and the front wheel brake Bf is always in a conductive state, the output oil pressure of the first output port 18 ₁ is directly transmitted to the front wheel brake Bf. As a result, before,
The brake oil pressures of the rear wheel brakes Bf and Br increase along a brake oil pressure distribution line A shown in FIG. This characteristic approximates the ideal braking oil pressure distribution curve B of a motorcycle, and allows the operator to easily perform efficient braking.

During braking, as the first brake piston 15 ₁ moves forward, the control piston 40 is also moved forward via its piston rod 15 ₁ a, but normally the control hydraulic chamber 42 communicates with the reservoir R via a normally open control valve 49. Therefore, the hydraulic oil in the control hydraulic chamber 42 is discharged to the reservoir R side as the control piston 40 moves forward, and hardly acts as a resistance to the braking input.

If the front wheel Wf tries to lock up during braking, the signal processing device C shown in FIG. A valve closing signal is sent to the open type control valve 49, and a valve opening signal is sent to the normally closed type control valve 48.
When these control valves 48 and 49 operate according to the above-mentioned signals, the oil passage 51 is shut off and the oil passage 50 is made conductive, so that pressure oil is supplied from the pressure accumulator Ac to the oil passage 50.
The hydraulic pressure is supplied to the control hydraulic chamber 42 through the hydraulic pressure, and the hydraulic pressure causes the control piston 40 to move into the first braking piston 15 ₁
is slightly retreated against the braking input, thereby reducing the pressure inside the first braking hydraulic chamber ₁₇₁ . As a result, the braking force of the front wheel brake Bf is reduced, and the locking phenomenon of the front wheel Wf is avoided.

Then, the signal processing device C detects the situation, returns both control valves 48 and 49 to their normal positions, and depressurizes the control hydraulic chamber 42. As a result, the braking force of the front wheel brake Bf increases again, and by repeating the above operations at high speed, the front wheel Wf is efficiently braked without locking up.

The retreat of the first brake piston 15 ₁ due to the operation of the control piston 40 conversely brings about an increase in the pressure in the second brake hydraulic chamber 17 ₂ , but since this increase in pressure is instantaneous, the pressure in each part of the hydraulic system of the rear wheel brake Br is increased. It is absorbed by elastic deformation, and therefore does not impair the operating feel of the brake lever 1 and brake pedal 2.

In this way, even while the anti-lock device Al is controlling the braking force of the front wheel brake Bf, the braking force of the rear wheel brake Br can be freely adjusted by adjusting the braking input to the second brake piston ₁₅₂ . Can be done.

When the brake lever 1 and brake pedal 2 are released to release the brakes on the front wheel Wf and rear wheel Wr, the first and second brake pistons 15 ₁ are moved by the elastic forces of the first and second return springs 26 ₁ and 26 ₂ . , 15 ₂ retreat, and the first and second brake hydraulic chambers 17 ₁ , 1
When the pressure inside the piston cups 32 ₁ and 32 2 is reduced to below atmospheric pressure, the outer periphery of the piston cups 32 1 and 32 ₂ is compressed into each brake hydraulic chamber 17 due to the pressure difference between _the pressure inside the replenishment oil chambers 33 ₁ and 33 ₂ under atmospheric pressure.
_{1 ,} 17 ₂ to create a gap between the inner wall _of the first cylinder hole 14 and _the inner wall of the first cylinder hole _{14 .}
17 ₂ , and the surplus oil is returned to the oil passage 35 from each relief port 37 ₁ , 37 ₂ and, therefore, to the reservoir R. During this time, each replenishment oil room 33
Supply port 38 is connected to ₁ , 33 ₂ by oil passage 36.
It is refueled _{through 1,382 .}

On the other hand, even when the control piston 40 is retracted, oil is supplied from the replenishment oil chamber 43 to the control hydraulic chamber 42 through the oil supply hole 45 by the same action as described above. Therefore, in particular, by reciprocating the control piston 40, the control hydraulic chamber 42, the oil passage 51, the reservoir R,
Since oil circulation occurs in the path of the oil passage 35, the supply oil chamber 43, the oil supply hole 45, and the control hydraulic chamber 42, it is possible to prevent air bubbles from remaining in the control hydraulic circuit including the control hydraulic chamber 42.

As described above, according to the present invention, adjacent first and second cylinder holes are formed in a single cylinder body with a partition wall in between, and the first and second brake pistons are slidably engaged in the first cylinder hole. A first brake hydraulic chamber is defined between the partition wall and the first brake piston, and a first brake hydraulic pressure chamber is defined between the partition wall and the first brake piston.
and a second brake hydraulic chamber that generates hydraulic pressure by the advancement of the second brake piston between the second brake piston, and one of the first and second output ports provided in the first and second brake hydraulic chambers, respectively. a first pressure receiving part that communicates with the front wheel brake and the rear wheel brake with the second brake piston and receives a braking input from the manual first brake operation member to advance the second brake piston; a second pressure receiving part that advances the second brake piston in response to a braking input from the second dynamic brake operation member; Since the second brake piston can be actuated even with a brake input from , the rear wheel brakes can be operated together, making braking operations extremely easy.

Further, a control piston defining a control hydraulic chamber in the front part to which control hydraulic pressure can be applied from a hydraulic pressure source in a timely manner is slid into the second cylinder hole, and this control piston is connected to the first cylinder hole.
Since it is connected to the brake piston via a piston rod that protrudes from the front of the piston and slides through the partition wall, when the braking input is excessive, the brake hydraulic pressure in the first brake hydraulic chamber is reduced by applying control hydraulic pressure to the control hydraulic chamber. By reducing the pressure, the braking force of one wheel brake connected to the brake hydraulic chamber can be alleviated, and locking of one wheel can be prevented. At the same time, the hydraulic pressure of the second brake hydraulic chamber can be reduced by adjusting the braking input. ,
Therefore, the braking force of the other wheel brake can be freely adjusted, and therefore, braking can be easily and accurately performed according to road surface conditions and driving conditions.

Moreover, since the first and second braking hydraulic chambers and the control hydraulic chambers could be formed in series in a single cylinder body,
A tandem-type master cylinder with an anti-lock function that is small and simple in construction can be obtained, and it can be easily installed inside the narrow body of a motorcycle, greatly contributing to simplifying the structure of a braking device. Once removed, the three pistons, the first and second braking pistons and the control piston, and their attached parts can be inspected and repaired, resulting in good maintainability. Furthermore, since a stopper is provided at the tip of the piston rod to abut against the front surface of the partition wall and restrict the retraction limit of the first brake piston, the stopper structure of the first brake piston is simplified, and a screw hole is formed in the cylinder body. Since there is no need to do this, it is convenient for keeping the inside of the cylinder body oil-tight.

[Brief explanation of drawings]

The drawings show an embodiment of a braking device equipped with a master cylinder of the present invention. FIG. 1 is a transparent side view of a motorcycle equipped with the braking device, FIG. 2 is a plan view of the same, and FIG. The hydraulic circuit diagram of the device, Figure 4 is an enlarged vertical side view of the master cylinder, Figure 5 is the front,
In the brake hydraulic distribution ratio characteristic diagram of the rear wheel brake, line A
is the characteristic due to the braking device, and line B is the ideal characteristic. Ac……Pressure accumulator as a hydraulic power source, Bf, Br……
Front and rear brakes, Mf, Mr...Front and rear master cylinders as master cylinders, 1...Brake lever as first braking operation member, 2...Second
Brake pedal as a braking operation member, 13...
Cylinder body, 14, 39...first and second cylinder holes, _151,152 ...first and second braking pistons, _{151a ...} piston rod, 16...partition wall,
17 ₁ , 17 ₂ ...first and second brake hydraulic chambers, 18 ₁ ,
18 ₂ ...First and second output ports, 27...Stopper, 40...Control piston, 42...Control hydraulic chamber.

Claims (1)

[Claims] 1. First and second cylinder holes are formed adjacent to each other across a partition wall in the cylinder body, and first and second brake pistons are slid back and forth into the first cylinder hole, so that a space between the partition wall and the first brake piston is formed. a first brake hydraulic chamber that generates hydraulic pressure by the advancement of the first brake piston; and a second brake hydraulic chamber that generates hydraulic pressure by the advancement of the second brake piston between the first and second brake pistons. and defining first and second brake hydraulic pressure chambers provided in the first and second brake hydraulic chambers, respectively.
A front wheel brake is communicated with one of the output ports and a rear wheel brake is communicated with the other, and the second brake piston receives a brake input from a manual first brake operation member to advance the second brake piston. 1
A pressure receiving part and a second pressure receiving part which also receives a braking input from a foot-operated second brake operation member and advances the second brake piston are provided, and a control piston is slid into the second cylinder hole. A control hydraulic chamber is formed on the front side of the control piston to which control hydraulic pressure can be applied from a hydraulic source in a timely manner, and the control piston is connected to the first brake piston by a piston rod that protrudes from the front side of the control piston and slidably penetrates the partition wall. A master cylinder for a braking device of a motorcycle, the master cylinder being connected to the piston rod via a piston rod, and provided with a stopper at the tip of the piston rod that comes into contact with the front surface of the partition wall to restrict a source of retraction of the first braking piston.