JP3048119B2 - Nipple mounting structure of master cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for attaching a nipple for connecting a chamber inside a master cylinder body used for a hydraulic brake system of a vehicle or the like to the outside. In particular, the present invention relates to a technique for attaching a nipple for connecting a hose connecting the master cylinder and the hydraulic fluid reservoir when the hydraulic fluid reservoir is installed separately from the master cylinder main body.

[0002]

BACKGROUND OF THE INVENTION A hydraulic pressure source for a hydraulic brake system such as a vehicle includes a master cylinder and a hydraulic fluid reservoir for supplying hydraulic fluid to the master cylinder. When communication is made between the master cylinder and the hydraulic fluid reservoir, usually, a boss portion communicating with the cylinder bore is provided in the master cylinder body, and a nipple is connected to the boss portion. Generally, this nipple is integrated with the bottom of the hydraulic fluid reservoir and is directly connected above the master cylinder. However, depending on the shape of the vehicle or the like, there may be a case where it is necessary to separate the hydraulic fluid reservoir and the master cylinder from each other and place them at different locations due to space limitations.

In such a communication path between the master cylinder and the hydraulic fluid reservoir, it is necessary to securely attach the nipple itself to the boss in order to prevent the fluid from leaking. In particular, when the master cylinder and the hydraulic fluid reservoir are arranged apart from each other, the nipple becomes a separate member from the hydraulic fluid reservoir, and the nipple is likely to come off or shift due to an unexpected external force.

As a technique for preventing the nipple from coming off,
For example, as disclosed in Japanese Utility Model Publication No. 1-40779, there is known a method in which a flat plate-shaped stopper is applied to an outward flange on the nipple side by a mounting screw (bolt member). According to this method, it is possible to prevent the nipple from coming off by the stopper, but it has been found that there is a difficulty in obtaining a stable pressing force or in terms of the number of parts. It is considered that the main cause of these difficulties lies in the configuration in which the flat plate-shaped stopper is directly pressed by the screw coupling force. Specifically, since the traveling direction of the screw matches the direction of the pressing force, there is a possibility that the pressing force fluctuates due to variations in the screw connection, and that it is not always possible to obtain a sufficient pressing force. there will be. Furthermore, since the fixing screw for fixing the stopper is used, the number of parts is increased.

Therefore, according to the present invention, the nipple can be more firmly attached to the boss of the master cylinder,
An object of the present invention is to provide a technique capable of more reliably preventing a nipple from coming off. Another object of the present invention is to provide a technique advantageous in reducing the number of parts.

[0006]

According to the present invention, a pressing force for pressing a flange portion of a nipple from above is generated by utilizing a leverage action. In order to obtain an effective lever action, the traveling direction of the mounting bolt member and the direction of the pressing force are set so as to intersect, preferably substantially orthogonal. Further, it is more preferable that an elastic force is generated in the stopper, and therefore, it is optimal that the stopper itself is made of a metal plate material that is elastically deformed. This is because, when the stopper is fixed by tightening the bolt member, the moving force of the bolt member is enlarged in accordance with the leverage ratio, and the stopper is firmly pressed. Because it will be.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment, as described above, a stopper has a function of elastically deforming. Since the stopper has a role of pressing the flange portion of the nipple, a metal material is generally selected. By making it a plate-like member, a bending force, that is, an elastic force can be given to itself, and processing can be easily performed. In addition,
An elastic member such as rubber may be interposed at a screw connection portion of the bolt member to assist the elastic force generated by the stopper due to the deformation.

In addition, in order to obtain an effective leverage action, the screw connection direction is such that the screw is not loosened when an external force is applied in the nipple pull-out direction, that is, the nipple flange direction. The direction is set so as to intersect with the direction in which the holding force for holding the portion is generated.

The basis for obtaining the leverage action is a structure in which one end of the stopper is brought into contact with the master cylinder with a rotation fulcrum, and a screw connection portion of the bolt member is used as a support point (force point).
The other end of the stop is free to gain more leverage. Then, in response to the movement, the stopper hits the flange portion of the nipple, and generates a pressing force while being elastically deformed. In order to obtain this pressing force sufficiently, it is desirable to provide a support point at a position closer to the rotation fulcrum than the free end. As a specific example of this structure, for example, a stopper having a substantially L-shaped cross section, which has a bent portion on one side of a member for holding the flange portion of the nipple, can be given. In this example,
The leading end of the bent portion is bent to make contact with the master cylinder body. In a state where no excessive force is applied to the stopper, the remaining portion of the bent portion is separated from the master cylinder main body by an amount corresponding to the bending at the tip of the bent portion. Here, the stopper is elastically deformed so as to fill the gap by the moving force accompanying the screw tightening of the bolt member. Then, the bent end of the bent portion becomes a rotation fulcrum, and a pressing force is generated on a member for pressing the flange portion.

[0010] More preferably, the shape of the stopper is also bent in the same direction as the above-mentioned bent portion (hereinafter, referred to as a "first bent portion") on the other side of the member for pressing the flange portion of the nipple. Make it approximately U-shaped. A bent portion opposite to the first bent portion (hereinafter referred to as a “second bent portion”) includes:
A hole is provided through which the tip of a bolt member for screw-connecting the first bent portion and the master cylinder body can pass. By doing so, the rod-shaped bolt member is inserted between the first bent portion and the second bent portion of the stopper. Therefore, when an external force is applied in the direction in which the nipple comes off, the bolt member serves as a shield to prevent the stopper from moving. In this case, the size of the bolt through-hole is determined so that the second bent portion has a degree of freedom such that the second bent portion can be elastically deformed by receiving a pressing force by screw tightening.

The present invention can be applied not only to a single type master cylinder but also to a tandem type. The effect is particularly great if applied to a tandem type. In the tandem type, there are two nipples corresponding to two bosses, and these two nipples can be held down by a common stopper and bolt member. Therefore, the number of parts can be effectively reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS This embodiment is an example of application to a tandem type brake master cylinder, and FIG.
FIG. 2 is a top view, and FIG. 3 is a sectional view taken along line 3-3 in FIG. With reference to these drawings, first, the internal structure of the master cylinder will be clarified, and then the nipple mounting portion of the present invention will be described.

The master cylinder 10 of the tandem type has a cylinder body 12, in which a cylinder hole 14 having the same axis as the cylinder body 12 is provided. Cylinder hole 14
Is closed on the left side of the cylinder bottom 12b and open on the right side of the cylinder head 12h. The cylinder hole 14 has a large-diameter portion 14b at the opening, and the remaining portion 14a at the back has a uniform diameter.
smaller than b.

A secondary piston 22 is located in the cylinder hole 14 on the left side near the cylinder bottom 12b, and a cup-shaped member 23 and a bolt 2 are located on the right side thereof.
There is a primary piston 21 between them. The primary piston 21 and the secondary piston 22 have cup seals 25a and 25
b; 26a and 26b. As a result, the second hydraulic chamber 32 is located at the innermost part of the cylinder
A first hydraulic chamber 31 is defined between 1 and 22. The second hydraulic chamber 32 communicates with a front wheel brake device through an outlet (not shown), and the first hydraulic chamber 31 communicates with a rear wheel brake device through another outlet (not shown). ing.

The first and second hydraulic chambers 31,
32 are boss portions 71, 7 through relief ports 41 and 42, respectively, in a normal state without brake operation.
2 inside. In such a state, the return springs 51 and 52 for urging the respective pistons 21 and 22 toward the cylinder head 12h are provided. But,
When the brake is actuated, each piston 21, 22 overcomes the force of each return spring 51, 52 and moves toward the cylinder bottom 12b, the cup seal 25a closes the relief port 41, and the cup seal 26a closes the relief port 42. And the first and second hydraulic chambers 31, 3
2 generates hydraulic pressure.

In the cylinder body 12 of the master cylinder 10, bosses 71 communicating with the liquid supply chamber 33 around the outer periphery of the piston 21 through passages 43 and pistons 22 through passages 44 are provided at positions separated from each other in the axial direction. There is a boss portion 72 communicating with the liquid supply chamber 34 on the outer periphery of the boss portion 72. The nipples 81 and 82 are fitted to the boss portions 71 and 72 with grommet seals 91 and 92 as sealing members therebetween.

Here, the pressing force for pressing the outward flange portions 81f, 82f of the nipples 81, 82 from above is applied to the stopper 100 made of a metal plate and the stopper 100.
Is obtained by the bolt member 200 that supports. Stopper 10
No. 0 is made of spring steel and elastically deforms itself. The stopper 100 is a plate having a size that can be inserted between the two bosses 71 and 72, and has its own mounting portion 102s at the center.
Center portion 102 including the boss portions 7 at the left and right end portions thereof.
1 and 72 are provided, respectively. Each holding part 110, 1 from the center part 102 to the end part
The fold lines 103 and 104 are visible on the way to 20, and the fold lines are for absorbing the difference in height between the two bosses 71 and 72. Holes 112, 122 each having a shape suitable for the outer shape of the nipples 81, 82 are formed in each of the holding portions 110, 120.
Is open. The holes 112 and 122 have a regular polygonal shape (usually a pentagonal or hexagonal shape), and one side is open.
Needless to say, such non-circular holes serve to prevent the nipples 81 and 82 from rotating. Stopper 1
The outer portion of 00 has a bent flange for reinforcement.

The central portion 102 of the stopper 100 has a U-shaped cross section, and has a flat plate portion 102p continuous with the pressing portions 110 and 120, and its own mounting portion 102s described above, that is, 90 to 90 from the flat plate portion 102p. ° The bent first bent portion and the second bent portion 10 parallel to the first bent portion 102s
2q. First and second bent portions 102s, 10s
2q, as best shown in FIG.
There is a hole through which 0 passes.

On the other hand, the master cylinder body 12 has a mounting portion 12s protruding in the outer diameter direction of the cylinder hole 14 at an intermediate portion between the two boss portions 71 and 72. This mounting part 12
In s, a hole provided with a female screw matching the male screw of the bolt member 200 is opened. Therefore, the fastener 100 can be attached and fixed to the master cylinder main body 12 by screwing the first bent portion 102s of the fastener 100 and the mounting portion 12s of the master cylinder 12 with the bolt member 200. .

Referring again to FIG. 3, first bent portion 10
The tip 102r of the 2s protrudes toward the second bent portion 102q and contacts the master cylinder body 12. Now, in the state shown in FIG.
The first bent portion 102 corresponds to the bending amount of 2r.
s and the master cylinder body 12
A gap 106 is created. Here, the bolt member 200 is further screwed in a direction to eliminate the gap 106, that is, toward the mounting portion 12s of the master cylinder. Then, receiving the moving force of the bolt member 200, the stopper 100 is elastically deformed with the tip 102 r of the first bent portion 102 s abutting on the master cylinder body 12 as a fulcrum, so that a leverage action is generated. Therefore, the force by the lever action is also exerted on the pressing portions 110 and 120 that are continuous with the flat plate portion 102 p of the central portion 102 of the stopper 100, and the flange portions 81 of the nipples 81 and 82.
f, 82f. Therefore, nipple 8
1, 82 are firmly and stably attached to the master cylinder 10 by the stopper 100. In addition, since a pressing force is generated in the pressing portions 110 and 120 by the lever action, the pressing portions 11 and 120 are moved from the central flat plate portion 102p.
Nipple 81, 8 even if the span up to 0, 120 is long
2 can withstand the external force in the pull-out direction. Therefore, two nipples 8 can be formed by one stopper 100.
Since 1, 82 can be attached, the number of parts can be reduced.

In the embodiment shown in the drawings, an example is shown in which the hydraulic fluid reservoir is provided separately from the master cylinder.
The present invention can also be applied to a hydraulic fluid reservoir integrated with a master cylinder.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an example of a master cylinder to which the present invention is applied.

2 is a top view of the master cylinder of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Tandem type master cylinder 12 Master cylinder main body 71, 72 Boss 81, 82 Nipple 91, 92 Sealing member (grommet seal) 100 Stopper 102s First bent portion 102q Second bent portion 102r Tip (end) 200 Bolt member

Claims (5)

(57) [Claims] 1. A nipple connected to a boss portion of a master cylinder body via a sealing member to communicate a chamber inside the cylinder body to the outside, the nipple having an outward flange portion, A fixing structure for preventing the nipple from coming off from the boss portion by contacting a stopper on the portion, wherein the stopper is supported by a screw connection by a bolt member to the master cylinder body side. In a mounting structure in which a pressing force for pressing the flange portion is generated on the stopper by utilizing a moving force accompanying the screw connection of the bolt member, the stopper is screwed to the master cylinder body. The direction is a direction intersecting with the direction of the holding force for holding the flange portion by the stopper, and the moving force accompanying the screw connection is leveraged. The pressing force is converted to the pressing force by the action , and one end of the stopper is master-shouldered.
Contact with the main body of the cylinder to make a rotation fulcrum.
And the supporting point (point of force) by the bolt member is
A nipple mounting structure for a master cylinder , which is provided at a position closer to a rotation fulcrum . 2. The mounting structure according to claim 1 , wherein said stopper is made of an elastically deformable metal plate. 3. The stopper has a substantially U-shaped cross section having a first bent portion and a second bent portion on both sides of a plate-shaped member for holding a flange portion of the nipple. parts supports the head of the bolt member, the second curved portion has holes leading end of the bolt member to penetrate, Oh claim 1
Or the mounting structure according to 2 . Wherein said first bent portion protrudes its tip portion toward the second curved portion, the end portion which is the protruding is hitting the master cylinder body, serial to claim 3 <br/> Mounting structure. 5. The master cylinder is of a tandem type, has two bosses at positions spaced apart from each other in the axial direction of the cylinder body, and one stop is disposed between the bosses. The mounting structure according to any one of claims 1 to 4 , wherein the screw is screw-connected to the master cylinder body by a bolt member at an intermediate position between both bosses.