JP4167145B2 - Hydraulic master cylinder for vehicles - Google Patents

Description

  The present invention relates to a hydraulic master cylinder for a vehicle, and more particularly, to a structure of a hydraulic master cylinder in which one end opening portion of a cylinder body opened at both ends is closed with a lid member to form a cylinder hole.

  2. Description of the Related Art Conventionally, there is a vehicle hydraulic master cylinder in which a cylinder member is formed by attaching a lid member to one end opening of a cylinder body that is open at both ends. For example, in a plunger-type hydraulic master cylinder, a lid member is attached to one end opening of the cylinder body, a piston guide is mounted inside the cylinder body, and a cylinder hole is formed inside these. A primary piston and a secondary piston are inserted into the cylinder hole, a first hydraulic chamber is defined between the two pistons, and a second hydraulic chamber is defined between the secondary piston and the lid member. Yes.

The lid member is formed by integrally forming a cylindrical portion inserted into the cylinder body and a flange portion covering one end portion of the cylinder body, and a screw portion is provided on each of the inner periphery of the cylindrical portion and the cylinder body. ing. A tool insertion hole is formed on the outer surface of the lid member, and the lid member is inserted by inserting the cylindrical portion into the cylinder body, inserting the tool into the tool insertion hole, rotating it, and screwing the cylindrical portion into the cylinder body. The cylinder body is mounted (see, for example, Patent Document 1).
JP-A-8-113136

  However, since the above-described lid member is attached to the cylinder body by screwing the threaded portion formed in the cylindrical portion into the threaded portion formed on the inner periphery of the cylinder body, the lid member is inadvertent after installation. There was a risk of turning and loosening.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle hydraulic master cylinder that has a simple structure and prevents a cover member that is screwed into a cylinder body from rotating unintentionally.

In order to achieve the above object, the present invention provides a sleeve having a peripheral wall and a bottom wall and formed into a bottomed cylindrical shape and fitted with O-rings on the opening side and the bottom wall side of the peripheral wall, respectively. A bottomed cylinder is inserted through one end opening of a cylinder hole at both ends formed in the cylinder body , and the cylinder hole and the peripheral wall are liquid-tightly sealed, and a lid member is screwed to the one end opening. hole is formed, in the vehicle hydraulic master cylinder define a fluid pressure chamber between the bottom wall of the interpolated piston and the sleeve in the sleeve, the inner peripheral side of the one end opening of the cylinder body At least one concave portion is formed, and a thin portion is formed on the lid member, and the thin portion is bitten into the concave portion by caulking while the lid member is in contact with the bottom wall of the sleeve. It is characterized by.

  In the present invention, at least one recess is formed on either the inner peripheral side of the one end opening of the cylinder body or the outer peripheral side of the lid member, and on the other side, a thin portion that can be deformed so as to bite into the recess by caulking Therefore, the lid member screwed into the one end opening of the cylinder body can be prevented from rotating with a simple structure, and the lid member can be securely attached to the cylinder body.

  Hereinafter, an embodiment in which the present invention is applied to a plunger type hydraulic master cylinder will be described in detail with reference to the drawings. The cylinder body 2 of the master cylinder 1 of the present embodiment is formed in a cylindrical shape with both ends open, and has a piston insertion port 2a, a small diameter hole 2b slightly larger in diameter than the piston insertion port 2a, and the other end of the cylinder body. A medium-diameter hole 2c to be formed and a large-diameter hole 2d having a female screw are provided, and recesses 2e and 2e are formed facing the rear end side inner periphery of the large-diameter hole 2d. A first cup seal 3 is fitted in the engagement groove in the piston insertion port 2a, and a second cup seal 5 supported by the seal support 4 and a first piston guide 6 are fitted in the small diameter hole 2b. The A seal support member 7 is mounted between the small diameter hole 2b and the medium diameter hole 2c, and the third cup seal 8 and the fourth cup seal 9 are supported on both sides of the seal support member 7, and the medium diameter hole 2c. A sleeve 10 and a lid member 11 are attached to the large-diameter hole 2d.

  A second piston guide 12 is mounted inside the sleeve 10, and includes the piston insertion port 2 a, the seal support 4, the first piston guide 6, the seal support member 7, the second piston guide 12, and the bottom wall 10 a of the sleeve 10. Thus, the bottomed cylinder hole 13 is formed. A primary piston 14 and a secondary piston 15 are inserted into the bottomed cylinder hole 13, a first hydraulic pressure chamber 16 is interposed between the pistons 14, 15, and a space between the secondary piston 15 and the sleeve 10. Second hydraulic chambers 17 are respectively defined.

  The sleeve 10 is formed in a bottomed cylindrical shape having a peripheral wall and a bottom wall 10a, and O-rings 18 and 18 are fitted on the opening side and the bottom wall side of the peripheral wall. Further, an output port 10b communicating with the discharge port P formed in the medium diameter hole 2c of the cylinder body 2 is formed at an intermediate position of the peripheral wall, and is not shown through the output port 10b and from the discharge port P. Hydraulic fluid is supplied to the wheel brake device.

  The second piston guide 12 inserted into the sleeve 10 is formed in a cylindrical shape, and has a cup passage projecting into the lip of the fourth cup seal 9 and a fluid passage connecting the second fluid pressure chamber 17 and the output port 10b. I have. The sleeve 10 is inserted from the large diameter hole 2d of the cylinder body 2 toward the medium diameter hole 2c with the opening side facing the inside of the cylinder body 2, and the medium diameter hole 2c and the sleeve 10 are liquid-tight by the O-rings 18 and 18. Sealed.

  The lid member 11 is a cylindrical body having a male screw 11a on the outer periphery, and a hexagonal hole 11b for inserting a tool is formed at the center of the outer surface, and an annular recess 11c is formed on the outer peripheral side of the hexagonal hole 11b. A thin portion 11d is formed between the recess 11c and the male screw 11a. After inserting the sleeve 10 into the cylinder body 2, the male screw 11 a of the lid member 11 is screwed into the female screw of the large-diameter hole 2 d, and the end surface of the lid member 11 is brought into contact with the bottom wall 10 a of the sleeve 10. 11 prevents it from coming off.

  After the lid member 11 is screwed into the large-diameter hole 2d, the lid member 11 is prevented from rotating by deforming the thin portion 11d using a jig T as shown in FIG. The jig T is formed in a disk shape having substantially the same diameter as the lid member 11, and a protrusion for deforming the thin portion 11d is provided at a position corresponding to the recesses 2e, 2e on the outer peripheral side. The tip is formed in a taper shape with the tip side being thin. Further, the inner peripheral side of the protrusion is provided so as to be inserted into the annular recess 11 c of the lid member 11. After the lid member 11 is screwed into the large-diameter hole 2d, the thin portion 11d of the lid member 11 is pressed outward by inserting the protrusion of the jig T into the back of the annular recess 11c. As a result, the thin-walled portion 11d bites into the recesses 2e, 2e formed in the cylinder body 2, and the lid member 11 is prevented from rotating.

  The primary piston 14 is disposed on the opening side of the bottomed cylinder hole 13, and the secondary piston 15 is disposed on the bottom side. The primary piston 14 has a push rod receiving hole 14 a at the cylinder hole opening end and a large-diameter bottomed recess 14 b at the cylinder hole bottom end, and is attached to the tip of the cylinder body 2. The first cup seal 3 and the second cup seal 5 are liquid-tightly accommodated in the bottomed cylinder hole 13. In addition, a plurality of through holes are formed in the peripheral wall of the primary piston 14 provided with a bottomed recess 14b, and a guide pin 19 that connects the primary piston 14 and the secondary piston 15 is provided in the bottomed recess 14b. The retainer 20 is accommodated. The retainer 20 is formed in a cup shape having a length that can accommodate the guide pin 19, and a plurality of through holes are formed in the peripheral wall for communicating the inside and outside of the retainer.

  The secondary piston 15 is formed with a first bottomed recess 15a at the cylinder hole opening side end and a second bottomed recess 15b at the cylinder hole bottom side end, respectively, via the third cup seal 8 and the fourth cup seal 9. The retainer 21 is attached to the bottomed cylinder hole 13 in a liquid-tight manner, and the first bottomed recess 15a is fixed to the distal end portion of the guide pin 19. The first hydraulic chamber 16 is defined between the bottomed recess 14 b of the primary piston 14 and the first bottomed recess 15 a of the secondary piston 15. A coiled first return spring 22 is contracted between the retainers 20 and 21, and the primary piston 14 is always urged toward the cylinder hole opening side by the first return spring 22.

  The second hydraulic chamber 17 is defined between the second bottomed recess 15b and the bottom wall 10a of the sleeve 10 which is the bottom of the bottomed cylinder hole 13, and the second bottomed recess 15b and the sleeve 10 A coil-like second return spring 23 is contracted between the bottom wall 10 a and the secondary piston 15 is always urged toward the cylinder hole opening side by the second return spring 23. Further, a plurality of through holes are formed in the peripheral wall of the secondary piston 15 provided with the second bottomed recessed portion 15b on the bottom side of the cylinder hole.

  A pair of bosses project from the upper portion of the cylinder body 2, and a reservoir 24 is provided on the bosses via a grommet seal. A liquid passage hole 2f communicating with the bottom wall of the boss formed on the front side of the cylinder body is formed in the front side peripheral wall of the cylinder body 2, and the liquid support hole 2f is formed in the seal support 4. A communication hole 4a communicating with the inside of the bottomed cylinder hole 13 is formed, and the first hydraulic pressure chamber 16 is formed through a communication hole formed in the primary piston 14, the communication hole 4a, and the liquid communication hole 2f. , Communicated with the reservoir 24. Further, a liquid passage hole 2g communicating with a bottom wall of a boss portion formed on the rear side of the cylinder body is formed in the rear side peripheral wall of the cylinder body 2, and the liquid support hole 2g is formed in the seal support member 7. A communication hole 7a communicating with the inside of the bottomed cylinder hole 13 is formed, and the second hydraulic pressure chamber 17 is formed through a communication hole formed in the secondary piston 15, the communication hole 7a, and the liquid communication hole 2g. It communicates with the reservoir 24.

  In the master cylinder 1 formed as described above, the primary piston 14 and the secondary piston 15 are disposed at the positions shown in FIG. 4 by the resilient force of the return springs 22 and 23 when not in operation. The hydraulic chamber 16 and the second hydraulic chamber 17 communicate with the reservoir 24, respectively. When the push rod pushes the primary piston 14 during operation, the primary piston 14 advances the bottomed cylinder hole 13 toward the bottom while compressing the first return spring 22 in the first hydraulic pressure chamber 16, and at the same time, the secondary piston 14 The piston 15 starts to advance toward the bottom of the cylinder hole while compressing the second return spring 23. When the through hole of the secondary piston 15 is blocked by the fourth cup seal 9, the communication between the second hydraulic pressure chamber 17 and the reservoir 24 is blocked, thereby generating a hydraulic pressure in the second hydraulic pressure chamber 17. The pressurized hydraulic fluid is supplied from the bottom wall 10a side of the sleeve 10 to one brake system via the output port 10b of the sleeve 10 and the discharge port P of the cylinder body 2.

  With this advance, when the set load of the second return spring 23 and the pressure of the second hydraulic pressure chamber 17 sway the set load of the first return spring 22, the first hydraulic pressure chamber 16 is compressed and the first hydraulic pressure chamber 16 is compressed. A hydraulic pressure is generated in the hydraulic chamber 16, and this generated hydraulic pressure is supplied to the other brake system. When braking is released, the primary piston 14 and the secondary piston 15 are returned to their initial positions by the return springs 22 and 23.

  The lid member 11 screwed to the cylinder body 2 is prevented from rotating unintentionally because the thin portion 11d is crimped and bites into the recesses 2e and 2e of the cylinder body 2 as described above, and there is no risk of unintentional loosening. The sleeve 10 can be reliably prevented from coming off.

The present invention is not limited to the one applied to the plunger-type master cylinder as in the above-described embodiment, and the bottomed cylinder hole is formed by closing one end opening of the cylinder body opened at both ends with a lid member. It can be applied to any type of master cylinder. Also, before Symbol recess may be one, or may be provided two or more.

The principal part expanded sectional view of the master cylinder which shows one example of this invention Explanatory drawing when attaching the lid member to the cylinder body Side view of a master cylinder showing an embodiment of the present invention Sectional drawing of the master cylinder which shows one example of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Master cylinder, 2 ... Cylinder main body, 2e ... Recessed part, 11 ... Cover member, 11a ... Male screw, 11b ... Hexagonal hole, 11c ... Annular recessed part, 11d ... Thin-walled part, 13 ... Bottomed cylinder hole, 14 ... Primary piston, 15 ... secondary piston, 16 ... first hydraulic chamber, 17 ... second hydraulic chamber, 24 ... reservoir, T ... jig

Claims (1)

A sleeve having a peripheral wall and a bottom wall and formed into a bottomed cylindrical shape and fitted with O-rings on the opening side and the bottom wall side of the peripheral wall is formed on the cylinder body with both end openings. is inserted from the one end opening, sealed liquid-tightly with the with the cylinder bore wall, and said by screwing the lid member to the opening at one end to form a bottomed cylinder bore, were interpolated to the sleeve In the vehicle hydraulic master cylinder in which a hydraulic chamber is defined between the piston and the bottom wall of the sleeve , at least one recess is formed on the inner peripheral side of the one end opening of the cylinder body, and the lid A vehicular hydraulic master cylinder in which a thin portion is formed in a member and the thin portion is bitten into the concave portion by caulking in a state where the lid member is in contact with a bottom wall of the sleeve .

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