JP2019064464A - Hydraulic device - Google Patents

Abstract

To abolish a separate separator which has been provided in a reserve tank.SOLUTION: A master cylinder 28 and a reserve tank 38 are separately provided, an inner cylinder boss 86, which is formed on a bottom of the reserve tank 38, is fitted to an outer cylinder boss 84 which is formed on an upper part of a cylinder body 70 of the master cylinder 28, and the master cylinder 28 and the reserve tank 38 are communicated with each other by a communication passage 80. The communication passage 80 comprises: a lower communication port 82 which is so formed as to penetrate the outer cylinder boss 84 and has a small opening area; an enlarged part 88 which is provided on the inner cylinder boss 86 and has a large opening area; and an upper communication port 56 which has a small opening area. The enlarged part 88 comprises a tapered hole 90 of which a diameter is expanded toward an underside of the inner cylinder boss 86, and a straight hole 92 which extends to the upper communication port 56 from above the tapered hole. The upper communication port 56 opens directly to a bottom 54 of the reserve tank 38.SELECTED DRAWING: Figure 5

Description

The present invention relates to a hydraulic device including a reserve tank and a master cylinder, which is used for a hydraulic brake or the like.

Some straddle-type vehicles such as motorcycles have a hydraulic front brake. The hydraulic structure of the front brake described in Patent Document 1 as an example includes a reserve tank and a master cylinder that are integrally formed. In addition, a communication passage is provided between the reserve tank and the master cylinder, and a separate body is provided on the upper part of the master cylinder around the communication passage so as to cover the master cylinder side communication port of the communication passage (reserve tank side opening of the communication passage). A structure is disclosed in which the separator of (1) is fitted and fixed.

Unexamined-Japanese-Patent No. 2010-221735

The above-mentioned separator is a separate body from the reserve tank, has a substantially hemispherical shape, and is provided with a reserve tank side communicating port which is a plurality of small holes, and the reserve tank side communicating port communicates the inside and the outside of the separator . However, since this separator is a separate body, it may rotate with respect to the fitting fixing portion. In addition, a separator retaining structure was required.

In order to solve the above problems, in the hydraulic device according to the present invention, a reserve cylinder (38) is connected via a master cylinder (28) and a connection portion (84, 86) above the master cylinder (28).
A communication passage (80) communicating the master cylinder and the reserve tank is formed in the connection portion,
The communication passage (80) includes a lower communication port (82) formed on the master cylinder side and an upper communication port (56) formed on the reserve tank side.
The opening area of the upper communication port (56) and the lower communication port (82) is the opening area of the intermediate portion (88) between the upper communication port (56) and the lower communication port (82) of the communication passage (80). It is characterized by being smaller than.

In this way, by integrally forming the upper communication port (56) in the reserve tank (38), air is mixed into the master cylinder (28) from the reserve tank side opening of the upper communication port (56). Upper and lower communication openings between the lower communication opening (82) and the upper communication opening (56) formed on the master cylinder side while preventing air biting more reliably and eliminating the separate separator conventionally provided Since the positional relationship of (1) can be fixed, the optimal arrangement for preventing splashing of the hydraulic fluid in the master cylinder (28) and air biting during maintenance such as hydraulic fluid replacement is maintained.
Furthermore, the opening area of the upper communication port (56) and the lower communication port (82) is smaller than the opening area of the middle portion (88). As a result, while squeezing the working fluid at the upper communication port (56) and the lower communication port (82), the pressure is relieved at the intermediate portion (88) having a large opening area. Therefore, the communication passage (80) is used for pressure relief, and the entire communication passage (80) becomes a pressure relief space.

In addition, the connecting portion is structured such that an outer cylinder boss (84) formed in the master cylinder (28) or the reserve tank (38) and an inner cylinder boss (86) formed in the other are fitted. None,
At the fitting portion between the outer cylinder boss (84) and the inner cylinder boss (86), and between the upper communication port (56) and the lower communication port (82), the outer cylinder boss (84) and the above A seal member (96) for fluidly connecting the inner cylinder boss (86) is disposed.
Even if a liquid-tight seal having a thickness in the longitudinal direction (vertical direction) of the communication passage (80) is provided on the outer periphery of the communication passage (80), a space for providing the seal member (96) can be secured. It can be done.

The master cylinder (28) is made of metal,
The reserve tank (38) is made of resin,
The outer cylinder boss (84) and the inner cylinder boss (86) are characterized in that one is made of metal and the other is made of resin.
In this case, the upper communication port (56) can be simultaneously provided at the time of molding of the resin reserve tank (38), and the resin boss can be protected by the metal boss while the moldability is improved. .

Further, portions (88, 56) of the communication passage (80) provided on the inner cylinder boss (86) of the resin reserve tank (38) are taken from the upper communication port (56) to the lower surface of the inner cylinder boss (86). The diameter is expanded toward 86a).
Thus, when the resin reserve tank (38) is formed, the portions (88, 56) of the communication passage (80) are inclined downward of the enlarged diameter portion and the lower portion of the inner cylinder boss (86) is tapered. As it can be removed, the mold can be simplified. Further, since the diameter is expanded in a tapered shape, a larger capacity of the communication passage can be secured.

Further, the seal member (96) is disposed at the upper part of the communication passage (80) that is biased toward the upper communication port (56) side. In this way, the seal member (96) can be held by the thick portion of the inner cylinder boss (86), and the sealing performance can be maintained well.

The upper communication port (56) and the lower communication port (82) are offset in the axial direction of the master cylinder (28).
In this way, the flow path of the hydraulic fluid is bent. For this reason, at the time of maintenance, the hydraulic fluid pressurized does not flow straight from the lower communication port (82) to the upper communication port (56) but is bent and flows to weaken the momentum, so that the droplets of the hydraulic fluid are hardly scattered. Become.

Further, the communication passage (80) is characterized in that the direction (that is, the vertical direction) along the opening direction is larger than the direction orthogonal to the opening direction (the vertical direction in FIG. 7) of the lower communication port (82). .
Thus, when the fluid pressure is applied to the communication passage (80) at the time of maintenance, the fluid pressure is applied in the longitudinal direction of the communication passage (80), that is, upward. For this reason, the communication passage (80), which is large in the vertical direction, can satisfactorily relieve the fluid pressure in the entire passage which is long in the pressure direction of the fluid pressure.

According to the present invention, by forming the upper communication port (56) integrally with the reserve tank (38), the surface tension of the hydraulic fluid at the reserve tank side opening of the upper communication port (56) prevents air biting. Fixing the positional relationship of the upper and lower communication ports between the lower communication port (82) and the upper communication port (56) formed on the master cylinder side while eliminating the separate separator that was conventionally provided, and preventing air bite Maintain optimal placement for
Further, while the opening area of the upper communication port (56) and the lower communication port (82) is made smaller than the opening area of the middle portion (88), pressure can be relieved in the middle portion (88) having a large opening area. Therefore, the communication passage (80) can be used for pressure relief, and the entire communication passage (80) can be a pressure relief space.

Right side view of a two-wheeled vehicle to which the present invention is applied Top view of the front of the vehicle Front view of the front brake portion Top view near the reserve tank part with the cap removed Sectional view along line 5-5 in FIG. 4 Sectional view along line 6-6 in FIG. 4 The figure which expanded the vicinity part of the communicating path in FIG. 5

FIG. 1 shows the right side of a motorcycle to which the present invention is applied. FIG. 2 is a plan view of the front portion of the vehicle, and FIG. 3 is a front view of a front brake portion. In the present application, the left, right, front, back, upper and lower directions are based on the direction of the vehicle. Further, in FIGS. 1 to 3, the upper side is Up, the lower side is Dwn, the front side is Fw, the rear side is Rr, the left side is Lh, and the right side is Rh.

As shown in FIG. 1, in this two-wheeled motor vehicle, an engine 14 is disposed between a front wheel 10 and a rear wheel 12, a fuel tank 16 is disposed above the engine 14, and a seat 18 is disposed behind the fuel tank.
The front wheels 10 are supported by the lower ends of the left and right front forks 20. An upper portion of the front fork 20 is supported by a top bridge 22 and a bottom bridge 24 which are rotatably supported at the front end of a vehicle body frame 15 supporting the engine 14.

A cylindrical bar handle 26 is attached to the top bridge 22 so that the front wheel 10 can be steered by the bar handle 26.
As also shown in FIGS. 2 and 3, the bar handle 26 extends to the left and right of the vehicle body, the master cylinder 28 is attached to the bar handle 26 on the right side, and hydraulic pressure is generated by gripping the brake lever 30. As shown in FIG. 1, it is transmitted to the brake caliper 34 through the brake hose 32. The brake caliper 34 is in sliding contact with a brake disc 36 provided on the side surface of the front wheel 10 for braking.

As shown in FIG. 5 which will be described in detail later, the master cylinder 28 has a handle mounting portion 29 integrated. A separate reserve tank 38 is coupled to the upper side of the master cylinder 28 by fitting. The interior of the master cylinder 28 and the reserve tank 38 are communicated with each other through a communication passage 80 described later, so that the hydraulic fluid (brake fluid) can flow in and out.

The handle mounting portion 29 is provided with a groove having a semicircular cross section for receiving the front portion of the bar handle 26. A handle holder 40 similarly provided with a groove having a semicircular cross section is covered from behind with respect to a handle attachment portion 29 in which the bar handle 26 is accommodated in a groove having a semicircular cross section, and by clamping the bar handle 26 while clamping. The master cylinder 28 is non-rotatably attached to the bar handle 26.
The cylinder hole 72 of the master cylinder 28 is disposed substantially in the front-rear direction in front of the bar handle 26. Further, at the front of the master cylinder 28, one end of the brake lever 30 is rotatably supported by a pivot 42.

The handle holder 40 is provided with a boss 41, and the lower end portion of the support post of the rearview mirror 44 is supported by screws or the like. Reference numeral 46 is a meter, 48 is a headlight, and 49 is a front blinker.
The master cylinder 28, the brake lever 30, the brake hose 32, the brake caliper 34, the brake disc 36, and the reserve tank 38 constitute a hydraulic front brake.

Next, configurations of the master cylinder 28 and the reserve tank 38 will be described.
FIG. 4 is a plan view showing the reserve tank 38 from above with the cap 50 (see FIG. 3) of the reserve tank 38 removed. FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4, and a direction X parallel to the line 5-5 is referred to as an axial direction of the master cylinder 28.
FIG. 6 is a cross section taken along line 6-6 in FIG. 4, and a direction Y parallel to the line 6-6 is referred to as an axis orthogonal direction of the master cylinder 28. FIG. 7 is an enlarged view of the vicinity of the communication passage in FIG.

In FIG. 4, the reserve tank 38 includes a cap 50 and a tank body 52. The cap 50 and the tank body 52 are made of resin. The tank main body 52 is opened upward, and the opening edge thereof has a polygonal shape whose shape in plan view is long in the direction perpendicular to the cylinder axis (Y direction). The side wall 52a on one side in the length direction is shorter than the side wall 52b on the other side, and the capacitance near the side wall 52a is smaller than the side wall 52b.
The bottom portion 54 is formed with a substantially heart-shaped recess 55 at a position biased toward the side wall 52a.

At the center of the bottom portion 54, an upper communication port 56 which is a part of a communication passage with the master cylinder 28 is opened. The upper communication port 56 opens in the recess 55 of the bottom 54 at a biased position near the side wall 52 a. This opening position corresponds to the vicinity of one corner in the lengthwise direction in the bottom 54 (see FIG. 5).
Further, the vicinity of the two protrusions 55 a opened in a substantially V shape of the recess 55 is fastened to the upper surface of the master cylinder 28 by a screw 58.

The opening edge of the tank main body 52 forms a joint surface 52e with the cap 50, and the cap 50 stacked there is a virtual with respect to a boss 52f formed at a connection portion between the side wall 52a and the long side wall 52d. It is fastened by a bolt 60 shown by a line.
The bolt 60 is also fastened to the boss 52g formed in the middle portion of the side wall 52b. That is, the cap 50 is fastened to the tank body 52 by bolts 60 at two places in the length direction.

The master cylinder 28 is provided with a knocker 79 (FIG. 5) provided on a base portion 30a that is in the vicinity of the pivot shaft 42 of the brake lever 30 when the brake lever 30 is gripped and pivoted in the arrow a direction about the pivot shaft 42. The push rod 78 (the same) is pushed to generate hydraulic pressure in the master cylinder 28.

In FIG. 5, the master cylinder 28 is made of metal formed by casting or the like, and has a cylinder body 70 elongated in the cylinder axial direction. The cylinder body 70 is formed with a long bottomed cylinder hole 72 extending in the axial direction of the cylinder, in which a piston 74 is accommodated so as to be movable back and forth in the axial direction of the cylinder.
The movement of the piston 74 toward the bottom 73 of the cylinder hole 72 is referred to as forward movement, and the movement in the opposite direction is referred to as backward movement.
The piston 74 is urged in the backward direction by a return spring 76 provided on the bottom 73.

The cylinder hole 72 has an opening 70 a opened in the cylinder axial direction on the opposite side of the bottom 73, and one end of the push rod 78 accommodated inside is in contact with one end of the piston 74. The other end of the push rod 78 is in contact with a knocker 79 provided on the base 30 a of the brake lever 30. Therefore, when the brake lever 30 is gripped and turned in the direction of arrow a in FIG. 4, the knocker 79 pushes one end of the piston 74 and advances it against the return spring 76. A space between the bottom 73 and the piston valve 75 in the cylinder hole 72 is a pressure chamber 72 a.

The piston 74 is provided with a piston valve 75 in sliding contact with the inner wall of the cylinder hole 72. When advancing with the piston 74, the hydraulic fluid is generated by pressing the hydraulic fluid in the pressure chamber 72a between the piston valve 75 and the bottom 73 Then, the pressurized hydraulic fluid is sent out to the brake hose 32 from a discharge port (not shown).

In the neutral state of piston 74 (the state in which brake lever 30 is opened), piston valve 75 is displaced to the backward side from lower communication port 82 of communication passage 80, and pressure chamber 72a via communication passage 80. The reservoir tank 38 communicates with the inside of the reservoir tank 38 so as to absorb the change in hydraulic fluid temperature and the change in hydraulic pressure caused by the vibration of the brake lever 30.
When the piston valve 75 advances to the bottom 73 side beyond the lower communication port 82, pressurization of the hydraulic fluid in the pressurization chamber 72a is started.

Further, in a state where the piston valve 75 opens the lower communication port 82, the hydraulic fluid in the reserve tank 38 can come in and out of the pressurizing chamber 72a through the communicating passage 80, and excess liquid in the pressurizing chamber 72a is reserved. Returning to the tank 38, conversely, the shortage of the hydraulic fluid can be supplied to the pressurizing chamber 72a. The communication passage 80 has an upper communication port 56 and a lower communication port 82 at the top and bottom, and is a passage that communicates the pressure chamber 72a of the master cylinder 28 with the reserve tank 38, which will be described in detail later.

As shown in FIGS. 5 and 6, a diaphragm 98 made of a bellows-like rubber member is liquid-tightly fitted to the reserve tank 38 so as to cover the opening edge of the tank body 52.
An air chamber 99 opened to the atmosphere is provided between the diaphragm 98 and the cap 50.

When the thick part formed around the diaphragm 98 is overlapped with the joint surface 52e (FIG. 4) which is the opening edge of the tank main body 52, the cap 50 is further overlapped with it and the bolt 60 is tightened. The thick-walled portion is in intimate contact with the bonding surface 52e and sealed in a liquid tight manner. When the bolt 60 is loosened, the air in the reserve tank 38 can be discharged to the outside from between the thick portion of the diaphragm 98 and the joint surface 52e.

Next, the communication passage 80 will be described in detail with reference to FIG. 7 together with FIGS. 5 and 6.
The lower communication port 82 is formed vertically through the bottom 85 a of a circular recess 85 formed inside the outer cylinder boss 84 formed on the upper surface of the cylinder body 70. The lower communication port 82 is a straight through hole, and its hole diameter is D1.
At the bottom portion 54 of the tank main body 52, an inner cylinder boss 86 fitted in the circular recess 85 is integrally formed by projecting downward.

An enlarged portion 88 is provided on the inner cylinder boss 86 from the lower surface 86 a toward the upper communication port 56 in the upper direction. The enlarged portion 88 is a passage enlarged portion formed between the upper communication port 56 and the lower communication port 82 for relieving the pressure in the communication path, and includes a lower tapered hole 90 and an upper straight hole 92. The straight hole 92 is continuous with the upper communication port 56.

The tapered hole portion 90 has no tapered hole expanding downward, and the lower end is the largest diameter portion of the hole diameter, and is open to the lower surface 86 a of the inner cylinder boss 86. Assuming that the opening diameter (inner diameter) of the lower end is D2, D2 is as large as slightly smaller than the outer diameter of the lower surface 86a of the inner cylinder boss 86. Further, assuming that the inner diameter at the upper end of the tapered hole 90 is D3, the relationship of D2> D3 is satisfied.

The straight hole 92 is a straight hole (inner diameter is D3) extending upward from the upper end of the tapered hole 90, and communicates with the upper communication port 56 at the bottom 54.
The upper communication port 56 is a through hole smaller than the straight hole 92, and communicates the straight hole 92 with the inside of the tank body 52, and the inner diameter thereof is D4. D4 is slightly larger than D1 of the lower communication port 82.
The inner diameter of the lower communication port 82 is the smallest, and there is a relationship of D2>D3>D4> D1. However, the inner diameter D4 of the upper communication port 56 may be equal to or smaller than the inner diameter D1 of the lower communication port 82.

The opening area of the upper communication port 56 is the area of a circle whose diameter is the inner diameter D4, and the opening area of the lower communication port 82 is the area of the circle whose diameter is the inner diameter D1. The opening area of the portion between the communication port 56 and the lower communication port 82, that is, the enlarged portion 88) is the area of the circle with the inside diameter D2 as the diameter and the area of the circle with the inside diameter D3 as the minimum. The opening area of each of the upper communication port 56 and the lower communication port 82 is smaller than the opening area of the middle portion.

The lower communication port 82, the enlarged portion 88 including the tapered hole portion 90 and the straight hole portion 92, and the upper communication port 56 communicate with each other to form a communication path 80 for communicating the pressurizing chamber 72a with the interior of the reserve tank 38.
The positions of the upper communication port 56 and the lower communication port 82 are offset in the cylinder axial direction so as not to overlap in the vertical direction. This positional relationship is always maintained constant because the upper communication port 56 is integrally formed with the reserve tank 38 and the lower communication port 82 is integrally formed with the master cylinder 28.

In the cylinder axis orthogonal direction shown in FIG. 6, the positions of the upper communication port 56 and the lower communication port 82 can be offset so as not to overlap even in the circumferential direction of the cylinder hole 72.
Thus, when the positions of the upper communication port 56 and the lower communication port 82 are offset, the flow of the hydraulic fluid from the pressure chamber 72a to the reserve tank 38 during the maintenance is bent as shown by arrow b in FIG. As a result, the discharge pressure into the reserve tank 38 is relieved.

Thereby, in a state where the cap 50 is removed at the time of maintenance, it is possible to prevent the scattering of the hydraulic fluid discharged to the reserve tank 38.

Further, the communication passage 80 is larger in the direction (that is, the vertical direction) along the opening direction than in the direction (the horizontal direction in FIG. 6) orthogonal to the opening direction (the vertical direction in FIG. 7) of the lower communication port 82.
As a result, when the fluid pressure is applied to the communication passage 80 at the time of maintenance, the fluid pressure can be favorably alleviated in the entire passage which is long in the fluid pressure pressurizing direction.
Furthermore, the hydraulic pressure can be alleviated also in the enlarged portion 88 in the middle portion of the communication passage 80.

The reserve tank 38 and the master cylinder 28 are connected by fitting the inner cylinder boss 86 to the outer cylinder boss 84 as shown in the state where the reserve tank 38 and the master cylinder 28 are separated in the circled portion in FIG. 7. . Therefore, the inner cylinder boss 86 and the outer cylinder boss 84 constitute the connecting portion of the present invention. A communication passage 80 having an upper communication port 56 and a lower communication port 82 is formed in the connecting portion. Thus, when the connecting portion is constituted by the metal outer cylinder boss 84 and the resin inner cylinder boss 86 fitted inside thereof, the resin inner cylinder boss 86 is protected by the metal outer cylinder boss 84 be able to.

An annular groove 94 opened inward and upward is formed in the upper part of the inner circumferential surface surrounding the circular recess 85 of the outer cylinder boss 84, and the seal member 96 is accommodated in the inside. The seal member 96 is formed to have a thickness in the vertical direction, that is, in a direction in which the fluid pressure is applied during maintenance, and seals the fitting portion between the inner cylinder boss 86 and the outer cylinder boss 84 in a fluid-tight manner.

The tank body 52 is made of resin and is molded by a mold. At this time, the inner cylinder boss 86 is integrally formed, and the enlarged portion 88 and the upper communication port 56 are simultaneously formed. Moreover, the enlarged portion 88 and the upper communication port 56 are directed upward with the smaller upper communication port 56 (inner diameter D4) and the smaller straight hole 92 (inner diameter D3) smaller than the tapered hole 90 (maximum inner diameter D2) of the largest diameter. Since the holes change so that the inner diameter gradually decreases, by inserting the core having these hole shapes from below, it can be formed simultaneously with the formation of the tank body 52, and the enlarged portion 88 and the upper communication port 56 can be easily made It can be formed into

In addition, since the lowermost tapered hole portion 90 has a tapered shape in which the diameter is expanded downward, the die cutting is smoothened by this portion. However, these holes may be formed by machining from the lower surface 86 a side of the inner cylinder boss 86. Also in this case, the inner diameter of the back portion to be processed is gradually reduced, so that machining is easy.
In addition, by using a tapered hole, the capacity of the communication passage 80 (the enlarged portion 88) can be maximized.

Further, since the master cylinder 28 and the reserve tank 38 are separately provided, and the inner cylinder boss 86 of the reserve tank 38 is fitted to the outer cylinder boss 84 of the master cylinder 28, the circular shape of the outer cylinder boss 84 of the master cylinder 28 When a relatively small lower communication port 82 (inside diameter D1) is provided at the bottom of the recess 85, a series including a pressure relief space having upper and lower small communication ports 56 and 82 and an intermediate portion as an enlarged portion 88. The passage 80 can be easily formed.

Next, the operation of the present embodiment will be described. First, air biting prevention will be described. As shown in FIG. 7 and the like, the upper communication port 56 opened into the reserve tank 38 is narrowed because the inner diameter is reduced to D4, so that the air in the reserve tank 38 does not easily enter the upper communication port 56, and the air Biting is prevented.

More specifically, the surface tension of the internal working fluid 100 is large at the upper end portion 102 of the upper communication port 56 having a small inner diameter, as shown in the vicinity of the upper end portion of the upper communication port 56 in the circle of FIG. It becomes difficult for air 104 in the hydraulic fluid in reserve tank 38 to overcome this surface tension and enter into upper communication port 56. As a result, air is prevented from entering the communication passage 80 into the pressurizing chamber 72a of the master cylinder.

Further, as shown in FIG. 6, for example, even if the vehicle is inclined and the line L becomes parallel to the horizontal line, the upper communication port 56 is positioned above the lower communication port 82. For this reason, even when the vehicle is inclined, air in the working fluid in the reserve tank 38 does not easily enter into the upper communication port 56, so that it is difficult to cause air biting.
Even if the upper communication port 56 is directly opened as described above, air biting can be prevented.

Next, maintenance will be described.
For example, at the time of maintenance for replacing the hydraulic fluid, new hydraulic fluid to be supplied to the reserve tank 38 is sent to the brake hose 32 by repeatedly holding and releasing the brake lever 30. At this time, although sudden pressurization is avoided by operating the brake lever 30 slowly, in the configuration of the present application, it is possible to prevent splashing of the hydraulic fluid even if sudden pressurization occurs.

During this maintenance, when the pressurized hydraulic fluid flows from the master cylinder 28 toward the reserve tank 38, the hydraulic fluid is squeezed by the small lower communication port 82 and then enters the enlarged portion 88 and spreads. As a result, the pressure is lowered and the pressure is discharged again into the reserve tank 38 while being throttled again by the upper communication port 56. Therefore, the pressure of the hydraulic fluid discharged into the reserve tank 38 can be reduced by the communication passage 80, and the discharge pressure can be reduced.
In particular, the pressure relief in the enlarged portion 88 has a remarkable effect on the pressure drop of the hydraulic fluid.

Further, as shown in FIG. 7, since the positions of the upper communication port 56 and the lower communication port 82 are offset, the flow of the hydraulic fluid from the pressurizing chamber 72a to the reserve tank 38 during maintenance is as shown by arrow b. It becomes a bent flow and relieves the discharge pressure into the reserve tank 38. Therefore, this also makes it difficult for the hydraulic fluid to scatter during maintenance. The offset structure of the upper communication port 56 and the lower communication port 82 also has the master cylinder 28 and the reserve tank 38 separately, and the outer cylinder boss 84 of the master cylinder 28 is fitted with the inner cylinder boss 86 of the reserve tank 38. It became easy by having a compatible structure.

Moreover, the communication passage 80 is integrally formed with the master cylinder 28 and the reserve tank 38, and a separate separator as in the prior art can be eliminated. Therefore, it is possible to eliminate the need for the retaining structure while suppressing the increase in the number of parts. Moreover, the positional relationship between the upper communication port 56 and the lower communication port 82 can be kept constant.

Further, when the fluid pressure is applied to the communication passage 80 at the time of maintenance, the fluid pressure is applied to the longitudinal direction of the communication passage 80, that is, the upper side of FIG. Moreover, the communication passage 80 is larger in the direction along the opening direction than in the direction orthogonal to the opening direction (the vertical direction in FIG. 7) of the lower communication port 82.
Therefore, the communication passage 80, which is large in the vertical direction, can satisfactorily relieve the fluid pressure over the entire passage which is long in the direction of pressure application.

The present invention is not limited to the above embodiment, and various modifications and applications are possible within the principle of the invention. For example, the outer cylinder boss 84 may be provided on the reserve tank 38 side, and the inner cylinder boss 86 may be provided on the master cylinder 28 side. In this case, the outer cylinder boss 84 is made of resin, the upper communication hole 56 and the enlarged portion 88 are provided here, the inner cylinder boss 86 is made of metal, and the lower communication hole 82 is provided here. Further, the outer cylinder boss 84 made of resin is protected by the inner cylinder boss 84 made of metal fitted inside.

26: bar handle, 28: master cylinder, 38: reserve tank, 50: cap, 52 tank body, 56: upper communication port, 70: cylinder body, 72: cylinder hole, 72a: pressure chamber, 74: piston, 82 : Lower communication port, 86: Inner cylinder boss, 88: Enlarged part, 90: Tapered hole, 92: Straight hole

Claims (7)

A reserve tank (38) is connected via a master cylinder (28) and above the connection part (84, 86),
A communication passage (80) communicating the master cylinder and the reserve tank is formed in the connection portion,
The communication passage (80) includes a lower communication port (82) formed on the master cylinder side and an upper communication port (56) formed on the reserve tank side.
The opening area of the upper communication port (56) and the lower communication port (82) is the opening area of the intermediate portion (88) between the upper communication port (56) and the lower communication port (82) of the communication passage (80). A hydraulic system characterized in that it is smaller. The connecting portion has a structure in which an outer cylinder boss (84) formed in the master cylinder (28) or the reserve tank (38) and an inner cylinder boss (86) formed in the other are fitted.
At the fitting portion between the outer cylinder boss (84) and the inner cylinder boss (86), and between the upper communication port (56) and the lower communication port (82), the outer cylinder boss (84) and the above A hydraulic device according to claim 1, characterized in that a sealing member (96) is provided which fluidly connects the inner cylinder boss (86). The master cylinder (28) is made of metal,
The reserve tank (38) is made of resin,
The hydraulic apparatus according to claim 2, wherein one of the outer cylinder boss (84) and the inner cylinder boss (86) is made of metal and the other is made of resin. Portions (88, 56) of the communication passage (80) provided in the resin reserve tank (38) are directed from the upper communication port (56) to the lower surface (86a) of the inner cylinder boss (86). The hydraulic system according to claim 3, characterized in that the diameter is expanded. The hydraulic device according to claim 4, wherein the seal member (96) is disposed to be biased toward the upper communication port (56) of the communication passage (80). The upper communication port (56) and the lower communication port (82) are offset in the axial direction and the radial direction of the master cylinder (28) according to any one of claims 1 to 5, Hydraulic system. The hydraulic device according to claim 1, wherein the communication passage (80) is larger in a direction along the opening direction than in a direction orthogonal to the opening direction of the lower communication port (82).

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