JP4242311B2 - Hydraulic master cylinder for vehicles - Google Patents

Description

  The present invention relates to a hydraulic master cylinder for a vehicle in which brakes and clutches of automobiles, motorcycles and tricycles are operated with hydraulic pressure, and more specifically, between a primary piston and a secondary piston of a plunger type hydraulic master cylinder. The present invention relates to an assembly structure of a spring mechanism disposed in a defined first hydraulic chamber.

  Conventionally, a plunger type hydraulic master cylinder has a primary piston and a secondary piston inserted in a cylinder hole formed in a cylinder body, a concave portion on the bottom side of the cylinder hole of the primary piston, and a piston insertion side of the secondary piston. A spring mechanism mounting portion is provided, and a first hydraulic chamber is defined between the recess and the mounting portion, and a second hydraulic chamber is defined between the cylinder hole bottom side and the cylinder hole bottom portion of the secondary piston. A spring mechanism is provided in each of the first and second hydraulic pressure chambers to urge the primary piston and the secondary piston in the backward direction. The spring mechanism disposed in the first hydraulic chamber is inserted into the retainer and a substantially cylindrical retainer that contacts either the bottom surface of the recess or the mounting portion, and the head of the retainer is attached to the retainer. The base is constituted by a guide pin that is engaged with the bottom of the recess and the other of the attachment portion via an engagement plate, and a return spring that is contracted between the engagement plate and the retainer. Has been.

  Since such a spring mechanism is not connected to the primary piston or the secondary piston, it is difficult to assemble it to the primary piston or the secondary piston.

For this reason, an engagement groove is provided in the concave portion of the piston, and the piston and the spring mechanism are connected by expanding the outer peripheral portion of the return spring and engaging the engagement groove (for example, see Patent Document 1). ), One end of the return spring is engaged with the engagement plate, a plurality of protrusions are formed on the engagement plate, and the protrusions are press-fitted and fixed to the bottom of the recess, Have been proposed (for example, see Patent Document 2).
JP 10-44967 A JP 2002-104164 A

  However, in the thing of the above-mentioned patent document 1, it was difficult to engage the outer peripheral part which the diameter of the return spring expanded in the engagement groove, and the directionality of return spring assembly also occurred. In addition, the return spring having an enlarged outer peripheral portion is complicated in setting the spring force and is troublesome to manufacture. With the thing of patent document 2, when press-fitting the disk-shaped retainer which latched the end of the return spring in the bottom part of a recessed part, since comparatively strong force was required, workability | operativity was not good.

  Therefore, an object of the present invention is to provide a hydraulic master cylinder for a vehicle that can easily connect a piston and a spring mechanism and can easily perform the assembly work of the piston and the spring mechanism in a short time. Yes.

In order to achieve the above object, according to the present invention, in the first invention, a primary piston and a secondary piston are inserted into a cylinder hole formed in a cylinder body, a recess is formed on the cylinder hole bottom side of the primary piston, and the secondary piston is A mounting portion of a spring mechanism is provided on the piston insertion side of the piston, a first hydraulic chamber is provided between the concave portion and the mounting portion, and a second hydraulic chamber is provided between the cylinder hole bottom side and the cylinder hole bottom portion of the secondary piston. A hydraulic chamber is defined, and a spring mechanism is provided in each of the first and second hydraulic chambers to urge the primary piston and the secondary piston in the backward direction, and is arranged in the first hydraulic chamber. The spring mechanism provided is a substantially cylindrical retainer whose base end abuts on either the bottom surface of the recess or the mounting portion, and is inserted into the retainer, with the head in front. A guide pin that engages with the engagement plate provided on the bottom of the recess and the other of the attachment portion, and the base pin is contracted between the engagement plate and the retainer while being locked to the distal end portion of the retainer. In the vehicular hydraulic master cylinder constituted by a return spring, the retainer has a flange portion formed by folding back the base end portion in the outer peripheral side axial direction, and one of the bottom portion of the recess and the attachment portion Includes an engaging groove that engages the flange portion , the flange portion includes a contact portion that contacts the bottom portion of the engaging groove and a folded portion in the axial direction, and the diameter of the return spring is The return is engaged with the return spring and the engagement groove when the return spring has the same diameter from one end to the other end and is retracted between the engaging plate and the retainer. Predetermined between So as to have a gap, it is characterized in that it is set to a smaller diameter than the folded portion.

  In the second invention, the retainer includes a plurality of axial slits extending from the flange portion side.

  According to a third aspect of the present invention, the axial turn-up portion that forms the flange portion gradually increases in diameter toward the tip portion.

  In the first invention, the head portion of the guide pin is locked to the retainer, the base portion of the guide pin is locked to the engaging plate, and the return spring is contracted between the retainer and the engaging plate to provide the spring mechanism. By temporarily assembling and engaging the flange portion of the retainer with the engagement groove, the spring mechanism can be easily assembled to the piston. Further, since the return spring can use a spring having the same diameter from one end to the other end, the setting of the spring force is easy, and there is no directionality in assembly.

  In the second invention, since the flange portion is reduced in diameter by the slit, the flange portion can be easily engaged with the engagement groove with a small force. Moreover, the residual air inside the retainer can be satisfactorily discharged by the slit when the hydraulic fluid is filled.

  In 3rd invention, after engaging with the said engagement groove | channel, the said return piece of a flange part presses the outer peripheral side of an engagement groove | channel, and can attach a retainer to an engagement groove | channel reliably.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The hydraulic master cylinder 1 is formed with a bottomed cylinder hole 6 by attaching a lid member 5 composed of a sleeve 3 and a plug 4 to an opening on the bottom side of a cylinder body 2 having both ends opened. The primary piston 7 and the secondary piston 8 are inserted into the first. A first hydraulic pressure chamber 9 is defined between the primary piston 7 and the secondary piston 8, and a second hydraulic pressure chamber 10 is defined between the secondary piston 8 and the lid member 5, respectively. Are respectively provided with spring mechanisms 11 and 12 to urge the primary piston 7 and the secondary piston 8 in the backward direction.

  The cylinder body 2 is formed in a substantially cylindrical shape with both ends opened, and in order from the bottom side opening serving as the bottom of the cylinder hole, a large diameter female screw hole 2a into which the plug 4 is screwed, a sleeve insertion hole 2b into which the sleeve 3 is inserted, A piston insertion hole 2c for inserting the primary piston 7 and the secondary piston 8 and a small-diameter hole 2d for inserting the primary piston 7 are formed. The large-diameter female screw hole 2a includes a female screw on the inner side of the bottom side opening. Seal support members are mounted between the sleeve insertion hole 2b and the piston insertion hole 2c and on the piston insertion side of the piston insertion hole 2c. The first cup seal 13 and the second cup are attached to these seal support members, respectively. A seal 14 and a third cup seal 15 are respectively attached, and a fourth cup seal 16 is fitted on the inner peripheral surface of the tip small-diameter hole 2d. A piston guide 17 having a liquid passage communicating with the discharge port P1 of the cylinder body 2 is mounted on the inner peripheral surface of the piston insertion hole 2c.

  As described above, the lid member 5 includes the bottomed cylindrical sleeve 3 and the plug 4 that prevents the sleeve 3 from coming off. The sleeve 3 has an inner diameter that allows the secondary piston 8 to enter. The sleeve 3 is inserted into the cylinder body 2 through the seal rings 18 and 18 with the opening side facing the inside of the cylinder body 2. A piston guide 19 having a liquid passage is mounted. A small-diameter cylindrical spring guide 3a projects from the inner surface of the bottom wall of the sleeve 3 and a cylindrical convex portion 3b projects from the outer surface of the bottom wall toward the bottom side opening of the cylinder body 2. A liquid passage communicating with the discharge port P2 of the cylinder body 2 is formed on the peripheral wall. The plug 4 has a disk part 4a having a male screw on the outer periphery and a hexagonal convex part 4b protruding from the center of the outer surface of the disk part 4a. On the sleeve side surface of the disk part 4a, An accommodation recess 4c of the protrusion 3b formed in the sleeve 3 is formed. In the plug 4, a male screw is screwed into the large-diameter female screw hole 2 a of the cylinder body 2, and the disk portion 4 a is screwed inside the bottom side opening of the cylinder body 2. By this attachment, the convex portion 3b is accommodated in the accommodating concave portion 4c, the sleeve side end surface of the disc portion 4a and the bottom outer surface of the sleeve 3 come into contact with each other, and the sleeve 3 is prevented from coming off. Further, in the vicinity of the opening on the bottom side of the upper part of the cylinder body 2, a positioning pin 20 is mounted so as to protrude into the cylinder body 2, and the tip side is disposed on the outer surface side of the disk portion 4a. Thus, the cylinder hole 6 is formed in the cylinder body 2 by mounting the lid member 5 on the bottom side opening of the cylinder body 2.

  A primary piston 7 is disposed on the distal end side of the cylinder hole 6, and a secondary piston 8 is disposed on the bottom side. The primary piston 7 has a push rod receiving hole 7a on the tip side and a recess 7b on the bottom side of the cylinder hole. The closing member 21 attached to the piston insertion side opening of the cylinder body 2 and the third cup seal 15 and the fourth cup seal 16 is liquid-tightly accommodated in the cylinder hole 6. A plurality of through holes 7c are formed in the peripheral wall on the cylinder hole bottom side of the primary piston 7 having the recess 7b therein, and an engaging projection 7d is provided around the bottom of the recess 7b. The bottom of the mating protrusion 7d is the engaging groove 7e of the present invention. The secondary piston 8 has a concave portion 8a on the bottom side of the cylinder hole and a concave mounting portion 8b on the end surface on the primary piston side. The secondary piston 8 is liquid-tight in the cylinder hole 6 via the first cup seal 13 and the second cup seal 14. Is housed in. A plurality of through holes 8c are formed in the peripheral wall on the cylinder hole bottom side of the secondary piston 8 provided with a recess 8a, and a pin receiving recess 8d is formed in the center of the mounting portion 8b. The first hydraulic chamber 9 is between the recess 7 b of the primary piston 7 and the mounting portion 8 b of the secondary piston 8, and the second hydraulic chamber 10 is between the recess 8 a of the secondary piston 8 and the sleeve 3. Each is defined.

  The spring mechanism 11 disposed in the first hydraulic pressure chamber 9 is inserted into the retainer 22 whose base end is in contact with the bottom surface of the recess 7 b of the primary piston 7, and the head 23 a is inserted into the retainer 22. A guide pin 23 that engages with the engagement plate 24 that engages with the distal end portion and engages the base portion 23b with the attachment portion 8b, and a first return spring that is contracted between the engagement plate 24 and the retainer 22. 25. As shown in FIG. 2, the retainer 22 includes a truncated cone-shaped guide portion 22 a and a flange portion 22 b formed on the proximal end side of the guide portion 22 a, and the guide portion 22 a An insertion hole 22c for locking the large-diameter head portion 23a of the guide pin 23 and allowing the retainer 22 to move along the shaft portion of the guide pin 23 is formed. The holes 22d are formed at equal intervals in the circumferential direction. A slit 22e is formed in the axial direction from the end of the flange portion 22b to each liquid passage hole 22d. The flange portion 22b has a base end of the guide portion 22a folded back in a substantially L-shaped cross section in the outer peripheral side axial direction, and includes a contact portion 22f that contacts the bottom surface of the concave portion 7b and an axial turn-up portion 22g. 22g is formed so that a diameter may be gradually expanded toward a front-end | tip part. Further, the diameter of the first return spring 25 is smaller than the outer diameter of the folded portion 22g. The engaging plate 24 is formed in a cylindrical shape having a locking hole 24a for locking the base side of the guide pin 23 at the center.

The spring mechanism 11 locks the head 23 a of the guide pin 23 in the insertion hole 22 c of the retainer 22, and engages the base side of the guide pin 23 with the locking hole 24 a of the engagement plate 24. The first return spring 25 is contracted between the contact portion 22f and the bottom surface 24b of the engaging plate 24, and the spring mechanism 11 is temporarily assembled. In this temporary assembly state, between the end portion and the folded portion 22g of the first return spring 25, the diameter of the first return spring 25, by setting the diameter smaller than the inner diameter of the folded portions 22g, the inner diameter A gap C1 is set between The spring mechanism 11 temporarily assembled in this manner locks the engaging plate 24 to the mounting portion 8b, accommodates the base portion 23b of the guide pin 23 in the pin accommodating recess 8d, and the flange portion 22b of the retainer 22 to the recess 7b. When pushed into the bottom, the folded portion 22g passes over the engaging protrusion 7d while deforming to the inner peripheral side without contacting the first return spring 25 by the gap C1, and the first return spring 25 is engaged together with the flange portion 22b. Engage with the mating groove 7e. Thereby, the spring mechanism 11 is assembled | attached to the said recessed part 7b and the attaching part 8b.

  The spring mechanism 11 disposed in the second hydraulic pressure chamber 10 is composed only of the second return spring 26, and the second return spring 26 has a spring guide 3a having one end formed on the sleeve 3 and the other end aforesaid. It is brought into contact with the bottom surface of the recess 8a and is contracted between the sleeve 3 and the recess 8a.

  A pair of boss portions 2e and 2f are projected from the upper portion of the cylinder body 2, and a reservoir 27 is provided on the boss portions 2e and 2f via a grommet seal. The peripheral wall of the piston insertion side opening of the cylinder body 2 is provided with a liquid passage hole 2g communicating with the bottom wall of the boss portion 2e formed in the vicinity of the piston insertion side opening of the cylinder body 2, and the seal support Are provided with a communication hole communicating with the liquid passage hole 2g and the inside of the cylinder hole 6, and the first hydraulic pressure chamber 9 includes a through hole 7c formed in the primary piston 7, the communication hole and the liquid passage hole. It communicates with the reservoir 27 via 2g. Further, a liquid passage hole 2h communicating with the bottom wall of the boss portion 2f formed in the vicinity of the opening on the bottom side of the cylinder body 2 is formed in the peripheral wall of the opening on the bottom side of the cylinder body 2. A communication hole communicating with the liquid passage hole 2h and the inside of the cylinder hole 6 is formed, and the second hydraulic pressure chamber 10 includes a through hole 8c formed in the secondary piston 8, the communication hole and the liquid passage hole 2h. It communicates with the reservoir 27 via

  The reservoir 27 has a shape that protrudes to the bottom side of the cylinder body 2 because of its attachment to the vehicle body. The lower half body 27a and the upper half body 27b made of synthetic resin are heat-sealed, Is a storage chamber. Boss portions 27c and 27d are formed in the lower half body 27a, and the boss portions 27c and 27d are inserted into the boss portions 2e and 2f of the cylinder body 2 and mounted so as to project between the boss portions 2e and 2f. The cylinder body 2 and the interior of the reservoir 27 are communicated with each other by screwing a mounting piece 27e protruding between the piece 2i and the boss portions 27c and 27d. Further, a leg piece 27f extending to the vicinity of the head of the positioning pin 20 is provided at the bottom of the lower half 27a to prevent the positioning pin 20 from coming off. The upper half body 27b has a shape projecting to the bottom side of the cylinder body 2, and a hydraulic fluid inlet 27g is provided to be offset from the bottom side of the cylinder hole 6, and a reservoir cap is provided at the hydraulic fluid inlet 27g. 27h is installed.

  When the hydraulic master cylinder 1 formed as described above is not braked, the primary piston 7 and the secondary piston 8 are disposed at the positions shown in FIG. 3 by the resilient force of the return springs 25 and 26, The first hydraulic chamber 9 and the second hydraulic chamber 10 communicate with the reservoir 27, respectively. When the push rod pushes the primary piston 7 during operation, the primary piston 7 advances the cylinder hole 6 toward the bottom while compressing the first return spring 25 in the first hydraulic pressure chamber 9, and at the same time, the secondary piston 8 Starts to advance toward the bottom of the cylinder hole. When the through hole 8c of the secondary piston 8 is closed by the first cup seal 13, the communication between the second hydraulic pressure chamber 10 and the reservoir 27 is blocked, thereby generating a hydraulic pressure in the second hydraulic pressure chamber 10. . The pressurized hydraulic fluid passes through the fluid passage of the sleeve 3 and is supplied to one brake system via the discharge port P2 of the cylinder body 2.

  With this advance, when the set load of the second return spring 26 and the pressure of the second hydraulic pressure chamber 10 exceed the set load of the first return spring 25, the first hydraulic pressure chamber 9 is compressed and the first fluid is compressed. A hydraulic pressure is generated in the pressure chamber 9 and the pressurized hydraulic fluid passes through the fluid passage of the piston guide 17 and is supplied to the other brake system via the discharge port P1 of the cylinder body 2. When the braking is released, the primary piston 7 and the secondary piston 8 are returned to their initial positions by the return springs 25 and 26.

  The spring mechanism 11 disposed in the first hydraulic pressure chamber 9 of the present embodiment has the same diameter from one end to the other end of the first return spring 25, so there is no directivity when temporarily assembled. The spring force can be easily set. Further, after the guide pin 23, the retainer 22, the engaging plate 24, and the first return spring 25 are temporarily assembled as described above, the engaging plate 24 is locked to the mounting portion 8b, and the flange portion 22b of the retainer 22 is engaged. And the end portion of the first return spring 25 can be easily assembled to the primary piston 7 and the secondary piston 8 by engaging the engaging groove 7e. Further, by setting the diameter of the first return spring 25 to be smaller than the outer diameter of the folded portion 22g, a gap C1 is formed between the first return spring 25 and the folded portion 22g, and the flange portion 22b is engaged. When engaging with the mating groove 7e, the folded portion 22g is deformed to the inner peripheral side without contacting the first return spring 25 by the gap C1, and the flange 22 is formed by the plurality of slits 22e formed in the retainer 22. Since the diameter of the portion 22b is reduced, the flange portion 22b can be easily engaged with the engagement groove 7e with a small force. Further, the plurality of slits 22e and the liquid passage hole 22d allow the residual air inside the retainer 22 to be discharged well when the hydraulic fluid is filled. Further, since the folded portion 22g of the flange portion 22b is formed so as to gradually increase in diameter toward the tip portion, the folded piece 22g engaged with the engaging groove 7e is formed on the outer peripheral side of the engaging groove 7e. By being pressed, the retainer 22 can be securely attached to the engaging groove 7e.

  In the above-described embodiment, the flange portion of the retainer is brought into contact with the concave portion of the primary piston, and the base portion of the guide pin is engaged with the engagement plate provided in the attachment portion of the secondary piston. The flange portion of the retainer may be locked in an engagement groove formed in the mounting portion of the secondary piston, and the engaging plate that engages the base portion of the guide pin may be locked in the concave portion of the primary piston.

It is a principal part expanded sectional view of the hydraulic master cylinder which shows one example of this invention. It is a perspective view of a retainer. It is a partial cross section front view of a hydraulic master cylinder similarly.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fluid pressure master cylinder, 2 ... Cylinder main body, 2a ... Large diameter internal thread part, 2b ... Sleeve insertion hole, 2c ... Piston insertion hole, 2d ... Small diameter hole at the tip, 2e, 2f ... Boss part, 2g, 2h ... Liquid passage Hole, 3 ... Sleeve, 3a ... Spring guide, 3b ... Convex part, 4 ... Plug, 4a ... Disc part, 4b ... Hexagonal convex part, 4c ... Containing concave part, 5 ... Cover member, 6 ... Cylinder hole, 7 ... Primary Piston, 7a ... receiving hole, 7b ... concave portion, 7c ... through hole, 7d ... engaging projection, 7e ... engaging groove, 8 ... secondary piston, 8a ... concave portion, 8b ... mounting portion, 8c ... through hole, 8d ... Pin accommodating recess, 9 ... first hydraulic chamber, 10 ... second hydraulic chamber, 11, 12 ... spring mechanism, 13 ... first cup seal, 14 ... second cup seal, 15 ... third cup seal, 16 ... 4th cup seal, 17, 19 ... piston guide, 18 ... 20 ... positioning pin, 21 ... closing member, 22 ... retainer, 22a ... guide part, 22b ... flange part, 22c ... insertion hole, 22d ... liquid passage hole, 22e ... slit, 22f ... contact part, 22g ... folding 23, guide pin, 23a ... head, 23b ... base, 24 ... engagement plate, 24a ... locking hole, 24b ... bottom, 25 ... first return spring, 26 ... second return spring, 27 ... reservoir

Claims (3)

A primary piston and a secondary piston are inserted into a cylinder hole formed in the cylinder body, a concave portion is provided on the cylinder hole bottom side of the primary piston, and a spring mechanism mounting portion is provided on the piston insertion side of the secondary piston. A first hydraulic chamber is defined between the first piston chamber and the mounting portion, and a second hydraulic chamber is defined between the cylinder hole bottom side of the secondary piston and the cylinder hole bottom portion, and the first and second hydraulic chambers are defined. And a spring mechanism disposed in the first hydraulic pressure chamber, wherein the primary piston and the secondary piston are urged in the backward direction. A substantially cylindrical retainer whose base end abuts on one of the two sides, and is inserted into the retainer to lock the head to the front end of the retainer, while the base is In a hydraulic master cylinder for a vehicle, comprising a guide pin that is engaged with an engagement plate provided on the other side of the attachment portion and the attachment portion, and a return spring that is contracted between the engagement plate and the retainer. In the retainer, the base end portion is folded back in the axial direction on the outer peripheral side to form a flange portion, and an engagement groove for engaging the flange portion is formed on one of the bottom portion of the recess and the mounting portion. The flange portion includes an abutting portion that abuts on a bottom portion of the engaging groove and an axially folded portion, and the diameter of the return spring is the same from one end to the other end, and When the return spring is contracted between the engagement plate and the retainer, the predetermined portion is provided between the return spring and the folded portion engaged with the engagement groove. Smaller than the inner diameter of the folded part Vehicle hydraulic master cylinder, characterized in that it is set. The hydraulic master cylinder for a vehicle according to claim 1, wherein the retainer includes a plurality of axial slits extending from the flange portion side. 3. The hydraulic master cylinder for a vehicle according to claim 1, wherein the axial turn-up portion forming the flange portion gradually increases in diameter toward the tip portion. 4.

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