JP2012197050A - Hydraulic master cylinder for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic master cylinder for vehicle that can excellently operate a return spring and a plunger, while a turn spring can be excellently assembled without increasing the number of parts.SOLUTION: The bottomed cylindrical plunger 7 having a recessed part 7a where the bottom side of a cylinder hole 2a is opened is interpolated to a bottomed cylinder hole 2a formed in a cylinder body 2. The inner circumferential surface of the plunger 7 forms the recessed bottom face side of the plunger 7 smaller than the recessed part opening side in terms of a diameter, and forms a large diameter inner circumference part 7c in the recessed part opening side of the plunger, and small diameter inner circumference part 7d in the recessed part bottom face side of the plunger, respectively. A return spring 15 is formed in cylindrical shape of the diameter smaller than the small diameter inner circumference part 7d, and at the same time forms a fixing part 15a by forming one turn of the outermost end part of the one end part to the diameter smaller than the inner diameter of a large diameter inner circumference part 7c and larger than the inner diameter of small diameter inner circumference part 7d and the fixing part 15a is seated to a bottom face 7b of the recessed part 7a in a condition of being in press contact with the small diameter inner circumference part 7d.

Description

  The present invention relates to a vehicular hydraulic master cylinder that hydraulically activates a brake or clutch of an automobile or a motorcycle or a three-wheeled vehicle, and more specifically, a plunger having a recess opened on the bottom side of a cylinder hole is connected to the inner periphery of the cylinder hole. The present invention relates to a plunger-type hydraulic master cylinder for a vehicle that is slidably inserted into a cylinder hole via a cup seal provided on the cylinder.

  Conventionally, as a plunger type hydraulic master cylinder for a vehicle, a plunger having a recess opened on the bottom side of the cylinder hole is slidably inserted into the cylinder hole via a cup seal provided on the inner periphery of the cylinder hole, and the return One end of the spring is seated on the bottom surface of the concave portion of the plunger, and the other end is seated on the bottom surface of the cylinder hole, and the return spring returns the plunger to a preset initial position, that is, a non-actuated position. There was something like that.

  As the return spring, there is one which is formed in a conical shape having a gradually decreasing diameter from the other end portion toward the one end portion, a cylindrical retainer disposed on the bottom side of the cylinder hole, and a base portion which is inserted into the retainer. Is disposed between the bottom surface of the concave portion of the plunger and the bottom surface of the cylinder hole via a guide pin that is mounted on the bottom surface of the concave portion of the plunger (see, for example, Patent Document 1). In addition, the return spring is formed in a cylindrical shape, and the outer diameter of the return spring is the same as the inner diameter of the plunger, or the outer diameter of the return spring is slightly larger than the inner diameter of the plunger. There was one which was made to fix (for example, refer to patent documents 2).

JP 2001-180471 A Japanese Utility Model Publication No. 2-96257

  In the thing of the above-mentioned patent document 1, although a return spring can be arrange | positioned in the stable state and the assembly | attachment property is good, since a return spring is fixed using a retainer and a guide pin, the number of parts has increased. Moreover, in the thing of patent document 2, when seating the end part of a return spring on the recessed part bottom face of a plunger, since the return spring had to be inserted in the plunger in the press-fit state, the assemblability was not good.

  Further, in each of the above-mentioned patent documents, since the outer periphery of the return spring and the inner wall of the plunger are close to each other, the plungers come into contact with each other when they make a stroke, thereby supporting the operation of the return spring and the plunger. There is a risk of noise or noise.

  Accordingly, an object of the present invention is to provide a hydraulic master cylinder for a vehicle that can satisfactorily assemble a turn spring without increasing the number of parts and can operate a return spring and a plunger satisfactorily. .

  In order to achieve the above object, a hydraulic master cylinder for a vehicle according to the present invention includes a bottomed cylinder-shaped plunger having a bottomed cylinder hole formed in a cylinder body and having a recess opened on the bottom side of the cylinder hole. A slidably inserted through a cup seal provided on the inner periphery of the hole, a replenishing chamber for supplying hydraulic fluid into the cylinder hole is formed in the cylinder body, and the space between the plunger and the bottom of the cylinder hole is formed. And a hydraulic pressure chamber, and one end of a return spring for returning the plunger to a non-operating position is seated on the bottom surface of the concave portion of the plunger, and the other end is seated on the bottom surface of the cylinder hole. In the hydraulic master cylinder, the inner peripheral surface of the plunger is formed such that the concave bottom surface side of the plunger is smaller in diameter than the concave opening side, and the large diameter inner peripheral portion is formed on the concave opening side of the plunger. A small-diameter inner peripheral portion is formed on the bottom surface of the concave portion of the ranger, and the return spring is formed to have a smaller diameter than the small-diameter inner peripheral portion, and the outermost end portion of the one end portion is defined as the large-diameter inner peripheral portion. The inner diameter is smaller than the inner diameter of the inner diameter and the inner diameter of the inner diameter of the smaller diameter is larger than the inner diameter of the inner diameter of the small diameter to form a fixing portion. It is characterized by letting.

  The return spring may be formed in a cylindrical shape from the other end portion toward one end side, or may be formed in a conical shape having a gradually increasing diameter from the other end portion toward the one end portion. good. Further, the hydraulic chamber, the replenishing chamber, and the peripheral wall on the concave opening side of the plunger having the large-diameter inner peripheral portion penetrating through the inner and outer sides of the peripheral wall at an initial position of the non-actuated plunger. It is preferable to form a communication port that communicates with each other. Further, the inner peripheral surface of the opening end of the plunger may be chamfered.

  According to the vehicle hydraulic master cylinder of the present invention, the return spring is formed to have a smaller diameter than the small-diameter inner peripheral portion of the plunger, and only the outermost end portion at one end on the bottom surface side of the concave portion has a large-diameter inner peripheral portion. Since the inner diameter is smaller than the inner diameter of the portion and larger than the inner diameter of the inner peripheral portion of the small diameter, the return spring can be inserted into the plunger satisfactorily, and the one end is connected to the inner diameter portion of the small diameter inner portion. It can be seated on the bottom surface of the recess while being pressed against the bottom surface of the recess, and the assembly of the return spring can be improved. Furthermore, since the return spring can be satisfactorily seated on the bottom surface of the concave portion of the plunger without using components such as a retainer and a guide pin, the number of components does not increase. Further, the plunger opening side is thinner than the bottom side, so that the weight of the plunger can be reduced. Furthermore, since the outer periphery of the return spring is unlikely to come into contact with the inner peripheral wall of the piston, it is possible to ensure good operation of the return spring and the plunger, and to suppress problems such as the generation of abnormal noise due to contact.

  Further, by forming the return spring in a cylindrical shape from the other end portion toward the one end side, the return spring can be easily formed and can be satisfactorily inserted into the plunger. Furthermore, the return spring is formed in a conical shape having a gradually increasing diameter from the other end toward the one end, and the outermost end of the one end is formed to have a larger diameter than the inner diameter of the small inner peripheral portion. The return spring can be satisfactorily inserted into the plunger. Further, the communication port can be easily processed by providing the communication port on the peripheral wall on the concave opening side of the plunger that is thin. Furthermore, by chamfering the inner peripheral surface of the opening end of the plunger, the return spring can be easily inserted into the plunger even when the outermost end is a return spring having a large diameter.

It is sectional drawing of the hydraulic master cylinder for vehicles which shows the 1st form example of this invention. It is sectional drawing of the hydraulic master cylinder for vehicles which shows the 2nd form example of this invention.

  FIG. 1 is a diagram showing an embodiment of a hydraulic master cylinder for a vehicle according to the present invention. The hydraulic master cylinder for a vehicle 1 has a cylinder body 2 having a bottomed cylinder hole 2a and a bottom portion of the cylinder hole 2a. On the side, a union boss 2b protrudes, and a union hole 3 is formed in the union boss 2b. A boss portion 2d having a liquid passage hole 2c communicating with the cylinder hole 2a protrudes from the upper portion of the cylinder body 2, and is connected to a reservoir (not shown) via a seal member 4 at the boss portion 2d. A connector 5 is attached. Further, mounting brackets 2e, 2e for mounting the vehicle body project from the lower portion of the cylinder body 2, and a large-diameter hole 2f into which the tip side of the push rod 6 is inserted is provided on the cylinder hole opening side. A diameter cylinder portion 2g is provided continuously.

  A plunger 7 is slidably inserted into the cylinder hole 2a via a first cup seal 8 and a second cup seal 9, and the first cup seal 8 is located on the cylinder hole bottom side with respect to the liquid passage hole 2c. In the first seal groove 2h formed on the inner peripheral surface of the cylinder hole 2a, the second cup seal 9 is formed on the inner peripheral surface of the cylinder hole 2a closer to the cylinder hole opening than the liquid passage hole 2c. A hydraulic chamber 2j is defined between the bottom of the cylinder hole 2a and the second cup seal 9 and is fitted into the seal groove 2i. A replenishing chamber 2k that is continuous with the liquid passage hole 2c is formed on the inner peripheral surface of the cylinder hole 2a between the first seal groove 2h and the second seal groove 2i.

  The union boss portion 2b is formed with the union hole 3 that opens to the bottom of the cylinder hole, and the union hole 3 is formed with a female screw portion 3a into which the banjo bolt 10 is screwed. The banjo bolt 10 for fixing the banjo 12 fixed to the tip of the hydraulic pipe 11 is screwed. The banjo 12 is composed of a fixed tube 12a that is caulked and fixed to the end of the hydraulic pipe 11, a ring body 12b that is fixed to the union boss portion 2b by a banjo bolt 10, and a small-diameter neck tube 12c that connects them. A through hole 12d communicating with the hydraulic pipe 11 is formed across the neck tube 12c and the ring body 12b. The banjo bolt 10 is provided with a male screw 10b on the outer periphery on the tip side of the shaft portion protruding from the hexagonal head portion 10a, and communicates with the hydraulic chamber 2j and the through hole 12d of the ring body 12b inside the shaft portion. A fluid passage hole 10 c is formed, and the fluid pressure chamber 2 j communicates with the fluid pressure pipe 11 through the union hole 3, the fluid passage hole 10 c of the banjo bolt 10, and the passage hole 12 d of the banjo 12.

  The plunger 7 is formed in a bottomed cylindrical shape having a recess 7a that opens to the bottom side of the cylinder hole, and the inner peripheral surface of the plunger 7 is formed such that the bottom surface 7b side of the recess 7a is smaller in diameter than the recess opening side, A large-diameter inner peripheral portion 7c is formed on the concave opening side of the plunger, and a small-diameter inner peripheral portion 7d is formed on the concave bottom surface side of the plunger. Further, the peripheral wall on the concave opening side of the plunger 7 provided with the large-diameter inner peripheral portion 7c passes through the inner and outer sides of the peripheral wall, and the hydraulic chamber 2j and the replenishing chamber 2k are formed at an initial position in a non-operating state. A plurality of small-diameter communication ports 7e that communicate with each other are formed in the circumferential direction, and a chamfered portion 7f that is chamfered is provided on the inner peripheral wall of the open end of the large-diameter inner peripheral portion 7c. A spherical recess 7g is formed on the outer surface of the plunger 7 on the cylinder hole opening side so that the push rod 6 that pushes the plunger 7 contacts. In the push rod 6, a hemispherical large-diameter head 6a that abuts the spherical recess 7g is inserted into the cylinder hole 2a from the large-diameter hole 2f, and the engaging groove 2n formed on the inner periphery of the large-diameter hole 2f. The retaining ring 13 and the retainer 14 that are engaged with each other are prevented from coming off.

  Between the bottom surface 7b of the concave portion 7a of the plunger 7 and the bottom surface of the cylinder hole 2a, a return spring 15 for returning the non-operated plunger 7 to a predetermined initial position set in advance is disposed. One end is seated on the bottom surface 7b of the plunger 7 and the other end is seated on the bottom surface 2m of the cylinder hole 2a.

  The return spring 15 is a cylindrical coil spring having a smaller diameter than the small-diameter inner peripheral portion 7d of the plunger 7, and the outermost end of one end is smaller in diameter than the inner diameter of the large-diameter inner peripheral portion 7c. In addition, the fixed portion 15a is formed to have a diameter larger than the inner diameter of the small-diameter inner peripheral portion 7d, and the fixed portion 15a is seated on the bottom surface 7d in a state of being pressed against the small-diameter inner peripheral portion 7d continuous to the bottom surface 7d. Let

  As shown in FIG. 1, the hydraulic master cylinder 1 formed in this way is configured so that the communication port 7 e of the plunger 7 has a cylinder hole more than the first cup seal 8 due to the elastic force of the return spring 15 when not operating. The fluid pressure chamber 2j and the replenishing chamber 2k communicate with each other through the communication port 7e, and the fluid communication hole 2c, the replenishing chamber 2k, and the fluid communication hole 2k are connected between the reservoir and the fluid pressure chamber 2j. The hydraulic fluid can be circulated through the plurality of communication ports 7e.

  When braking, when the push rod 6 pushes the plunger 7 toward the bottom of the cylinder hole, the plunger 7 advances in the cylinder hole 2a toward the bottom of the cylinder hole while compressing the return spring 15, and the communication port 7e is the first cup seal. 8, fluid pressure starts to be generated in the fluid pressure chamber 2j from the time when the communication state between the fluid pressure chamber 2j and the replenishment chamber 2k is cut off, and the pressurized hydraulic fluid flows into the union hole 3 and the banjo bolt 10 The liquid is supplied to the hydraulic pipe 11 through the liquid passage hole 10 c and the passage hole 12 d of the banjo 12.

  When the braking is released, the plunger 7 returns to the initial position by the elastic force of the return spring 15. When the plunger 7 moves (retreats) toward the cylinder hole opening, the hydraulic fluid flows into the hydraulic chamber 2j through the first seal groove 2h while bending the first cup seal 8 from the reservoir, and the plunger 7 Retreat well.

  In the hydraulic master cylinder 1 described above, the return spring 15 is simply and reliably seated on the bottom surface 7d in a state where the fixed portion 15a of the return spring 15 is in pressure contact with the small-diameter inner peripheral portion 7d continuous with the bottom surface 7d. Can be assembled to the plunger 7. Further, when the plunger 7 and the return spring 15 are assembled to the cylinder hole 2a, the return spring 15 together with the plunger 7 is placed in the cylinder hole 2a in a state where the fixing portion 15a of the return spring 15 is fixed to the bottom surface 7d of the plunger 7. Since it is inserted and assembled, the plunger 7 and the return spring 15 can be assembled in the cylinder hole 2a satisfactorily. In addition, since components such as a retainer and a guide pin are not used for assembling the return spring 15 as in the prior art, there is no possibility that the number of components will increase. Further, the concave portion opening side of the plunger 7 is thinner than the bottom portion side, so that the weight can be reduced, and the communication port 7e is provided on the peripheral wall on the concave portion opening side of the thin plunger 7, thereby providing a communication port. 7e can be processed easily. Further, by providing the chamfered portion 7f on the inner peripheral surface of the open end of the large-diameter inner peripheral portion 7c, the plunger of the return spring 15 can be used even if the outermost winding is a large-diameter return spring. The insertion into the inside can be facilitated. Furthermore, since the outer periphery of the return spring 15 is unlikely to come into contact with the inner peripheral wall of the plunger 7, it is possible to ensure good operation of the return spring 15 and the plunger 7, and it is possible to suppress problems such as the generation of abnormal noise due to contact.

  FIG. 2 shows a second embodiment of the present invention. Components that are the same as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The return spring 16 used in the vehicle hydraulic master cylinder 1 of this embodiment is formed by a conical coil spring having a gradually increasing diameter from the bottom of the cylinder hole toward the bottom of the plunger. The fixed portion 16a is formed by forming one turn as the outer end portion with a diameter smaller than the inner diameter of the large-diameter inner peripheral portion 7c of the plunger 7 and larger than the inner diameter of the small-diameter inner peripheral portion 7d. . Since the return spring 16 of this embodiment is formed in a conical shape, it can be inserted well into the plunger.

  Note that the present invention is not limited to the case where the banjo bolt is screwed into the union hole as in the above-described embodiment, and the union bolt may be screwed. Further, the return spring of the present invention can be applied to a tandem hydraulic master cylinder having two plungers.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle hydraulic master cylinder, 2 ... Cylinder main body, 2a ... Cylinder hole, 2b ... Union boss | hub part, 2c ... Liquid through-hole, 2d ... Boss part, 2e ... Bracket, 2f ... Large diameter hole, 2g ... Large diameter Tube portion, 2h ... first cup seal groove, 2i ... second cup seal groove, 2j ... hydraulic pressure chamber, 2k ... replenishment chamber, 2m ... bottom surface, 3 ... union hole, 3a ... internal thread portion, 4 ... sealing material, 5 ... Connector, 6 ... Push rod, 7 ... Plunger, 7a ... Recess, 7b ... Bottom, 7c ... Large diameter inner periphery, 7d ... Small diameter inner periphery, 7e ... Communication port, 7f ... Chamfered portion, 7g ... Spherical recess 8 ... 1st cup seal, 9 ... 2nd cup seal, 10 ... Banjo bolt, 10a ... Hex head, 10b ... Male screw part, 10c ... Fluid passage, 11 ... Hydraulic piping, 12 ... Banjo, 12a ... Fixed Tube, 12b ... Ring body, 12c ... Neck , 12d ... through hole, 13 ... retaining ring, 14 ... retainer, 15, 16 ... the return spring, 15a, 16a ... fixing portion

Claims (5)

A bottomed cylindrical plunger having a recess that is open on the bottom side of the cylinder hole is slidably inserted into a bottomed cylinder hole formed in the cylinder body via a cup seal provided on the inner periphery of the cylinder hole. A replenishing chamber for supplying hydraulic fluid into the cylinder hole is formed in the cylinder body, a hydraulic chamber is defined between the plunger and the bottom of the cylinder hole, and the plunger is returned to the non-operating position. In the vehicle hydraulic master cylinder in which one end portion of the return spring is seated on the bottom surface of the concave portion of the plunger and the other end portion is seated on the bottom surface of the cylinder hole, the inner peripheral surface of the plunger is the concave portion of the plunger. The bottom surface side is formed to have a smaller diameter than the concave opening side, the large diameter inner peripheral portion is formed on the concave opening side of the plunger, and the small inner diameter portion is formed on the concave bottom surface side of the plunger. The inner spring is formed to have a smaller diameter than the small-diameter inner peripheral portion, and the outermost end portion of the one end portion is smaller in diameter than the inner diameter of the large-diameter inner peripheral portion and the inner diameter of the small-diameter inner peripheral portion. The vehicular hydraulic master cylinder is characterized in that a fixed portion is formed with a larger diameter than the inner diameter, and the fixed portion is seated on the bottom surface of the recess in a state where the fixed portion is pressed against the inner peripheral portion of the small diameter. The hydraulic master cylinder for a vehicle according to claim 1, wherein the return spring is formed in a cylindrical shape from the other end portion toward the one end side. The hydraulic master cylinder for a vehicle according to claim 1, wherein the return spring is formed in a conical shape having a gradually increasing diameter from the other end portion toward the one end portion. The hydraulic pressure chamber and the replenishing chamber communicate with each other at the initial position of the non-actuated plunger through the inside and outside of the peripheral wall through the peripheral wall on the concave opening side of the plunger having the large-diameter inner peripheral portion. The vehicle hydraulic master cylinder according to any one of claims 1 to 3, wherein a communication port is formed. The vehicular hydraulic master cylinder according to any one of claims 1 to 4, wherein an inner peripheral surface of an opening end of the plunger is chamfered.

Images