JP2008149743A - Vehicular hydraulic master cylinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plunger-type vehicular hydraulic master cylinder favorably usable for a vehicle with a vehicle behavior stabilization control system by enhancing replenishing performance of a hydraulic fluid and improving the durability of a cup seal with simple structure. <P>SOLUTION: A plunger 9 is provided with a large-diameter plunger section 9c slidingly contacting a cylinder hole 3 formed more closely to a cylinder hole opening side relative to the cup seal 11 in an non-operated state, a medium-diameter plunger section 9d with a diameter smaller than that of the large-diameter plunger section 9c, and at the same time, larger than the internal diameter of the cup seal 11, and a small-diameter plunger section 9e with a diameter smaller than the internal diameter of the cup seal 11 are formed consecutively. A communication port 9g is formed in the medium-diameter plunger section 9d. The cylinder hole 3 includes a small-diameter cylinder section 3f formed on the cylinder hole opening side in the fitting groove 3c of the cup seal 11, and a large-diameter cylinder section 3g formed at a position opposed to the large-diameter plunger section 9c in the non-operated state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hydraulic master cylinder for a vehicle in which a brake of an automobile, a motorcycle or a tricycle is operated with hydraulic pressure, and more specifically, is formed between a plunger of a plunger type hydraulic master cylinder and a cylinder hole. The present invention relates to a structure of a fluid passage and a communication port that communicates the fluid passage with a fluid pressure chamber.

In the plunger type hydraulic master cylinder, a liquid passage communicating with the hydraulic fluid passage formed in the cylinder body is formed between the plunger and the cylinder hole, and the plunger is in an inoperative state. A communication port for communicating the fluid passage with the fluid pressure chamber, and a bottomed groove extending toward the cylinder hole opening side of the communication port, so that a high fluid pressure is applied when the vehicle behavior stabilization control system is operated. There is one that prevents the communication port from being blocked by a deformed cup seal when supplied from the pressure circuit to the hydraulic pressure chamber (see, for example, Patent Document 1).
Also, a number of second communication ports having a smaller diameter than the communication port are formed on the cylinder hole opening side of the communication port of the plunger, and the communication port is formed by a cup seal that deforms when high hydraulic pressure flows into the hydraulic pressure chamber. There is one in which the fluid pressure chamber and the fluid passage are communicated with each other by the second communication port even if the fluid is blocked (see, for example, Patent Document 2).
JP 2006-168429 A Japanese translation of publication No. 2004-521005

  However, in the thing of the above-mentioned patent document 1, since the bottomed groove | channel had to be formed in the back of the communication port formed in the plunger, the effort of the plunger was taken. Further, when a high hydraulic pressure is supplied from the hydraulic circuit to the hydraulic chamber, the cup seal may be deformed to enter the bottomed groove and deteriorate.

  Moreover, in the thing of patent document 2, since many 2nd communication ports had to be formed by carrying out many small hole processing to a plunger, processing took time and the cost increased.

  Accordingly, the present invention provides a plunger type vehicle that has a simple structure, improves the replenishability of hydraulic fluid, improves the durability of the cup seal, and can be suitably used for a vehicle equipped with a vehicle behavior stabilization control system. An object of the present invention is to provide a hydraulic master cylinder.

  In order to achieve the above object, the present invention inserts a plunger in a slidable manner through a cup seal fitted in a bottomed cylinder hole formed in a cylinder body, and a hydraulic chamber is formed on the distal end side of the plunger. In the vehicular hydraulic master cylinder having a reservoir for supplying the hydraulic fluid to the hydraulic chamber, the plunger is in an inoperative state on the cylinder hole opening side than the cup seal in the cylinder hole. A large-diameter plunger portion that is in sliding contact with a medium-diameter plunger portion that is smaller in diameter than the large-diameter plunger portion on the cylinder hole bottom side of the large-diameter plunger portion and larger in diameter than the inner diameter of the cup seal A small diameter plunger portion smaller than the inner diameter of the cup seal is continuously formed at a position facing the cup seal on the cylinder hole bottom side of the diameter plunger portion, and the cylinder hole is A small-diameter cylinder portion on the cylinder hole opening side of the fitting groove for fitting the cup seal, and a large-diameter cylinder at a position facing the large-diameter plunger portion in an inoperative state on the cylinder hole opening side with respect to the small-diameter cylinder portion. Each of which is provided with a fluid passage hole communicating with the reservoir, and in a non-operating state, a gap between the large diameter plunger portion and the large diameter cylinder portion, and the medium diameter plunger portion, A fluid passage is formed by communication between the gap between the small diameter cylinder portion and the gap between the small diameter plunger portion and the cup seal, and the fluid pressure chamber communicates with the fluid passage hole through the fluid passage. The communication port is formed on the cylinder hole opening side of the plunger on the cylinder hole opening side, and the communication port is formed in the medium diameter plunger portion. The plunger moves forward to the bottom of the cylinder hole during operation of the tip of the large diameter plunger, and the inner peripheral side of the cup seal contacts the plunger to generate hydraulic pressure in the hydraulic chamber. Preferably, the cup seal is formed at a position that has passed through the small-diameter cylinder portion before the cup seal is deformed toward the small-diameter cylinder portion by the hydraulic pressure.

  The present invention is formed as described above, and has a simple structure, a liquid passage hole communicating with the reservoir, a gap between the large diameter plunger portion and the large diameter cylinder portion, and a medium diameter plunger portion when not in operation. Since the gap between the small diameter cylinder portion and the gap between the small diameter plunger portion and the cup seal communicate with each other to form a liquid passage, and the liquid passage communicates with the communication port, the hydraulic pressure from the reservoir The replenishment property of the hydraulic fluid to the chamber can be improved.

  Further, since the communication port is formed in the middle diameter plunger portion, the communication port and the cylinder hole do not come into sliding contact when the plunger slides in the cylinder hole, and there is no possibility of damaging the plunger or the cylinder hole.

  Furthermore, when the vehicle behavior stabilization control system is activated when not in operation and high hydraulic pressure is introduced from the hydraulic circuit into the hydraulic chamber, the high hydraulic pressure can be extracted to the reservoir through the communication port. The deformation of the cup seal can be suppressed as much as possible.

  In addition, when the plunger moves forward to the bottom of the cylinder hole during operation and a predetermined fluid pressure is generated in the fluid pressure chamber, the tip of the large diameter plunger portion is in a state of passing through the small diameter cylinder portion. Even if the cup seal is deformed by the hydraulic pressure generated in the chamber, the cup seal is not caught between the plunger and the cylinder hole, and the durability of the cup seal can be improved.

  Hereinafter, an embodiment in which the present invention is applied to a tandem hydraulic master cylinder will be described in detail with reference to the drawings. 1 is a cross-sectional front view of a hydraulic master cylinder, FIG. 2 is an enlarged cross-sectional view of a main part showing the hydraulic master cylinder from a non-operating state to an initial state of hydraulic pressure generation, and FIG. 3 is a cup seal that generates a predetermined hydraulic pressure. FIG. 4 is an enlarged cross-sectional view of the main part showing the hydraulic master cylinder immediately before the deformation of the hydraulic cylinder, and FIG. 4 is an enlarged cross-sectional view of the main part showing the hydraulic master cylinder in the hydraulic pressure generation state where the piston is further advanced than in the state of FIG. The pressure master cylinder 1 has a bottomed cylinder hole 3 formed in a cylinder body 2, and the cylinder body 2 includes a first output port 4 that opens on the bottom side of the cylinder hole 3, and a cylinder axially intermediate portion of the cylinder hole 3. A second output port 5 is formed in the opening.

  The cylinder body 2 has a pair of bosses 2a and 2b projecting from the upper part, and the bosses 2a and 2b have a first liquid passage hole 6a and a second liquid passage hole 6b communicating with the cylinder hole 3, respectively. Are connected to each other, and a reservoir 8 is attached to the boss portions 2a and 2b via grommet seals 7a and 7b.

  A first plunger 9 is slidably inserted into the cylinder hole 3 via cup seals 10 and 11, and a second plunger 12 is slidably inserted via the cup seals 13 and 14. The cup seals 10 and 11 are fitted into fitting grooves 3b and 3c formed on the cylinder hole bottom side and the cylinder hole opening side of the first liquid passage hole 6a of the cylinder hole 3, respectively. Are fitted in fitting grooves 3d and 3e formed on the cylinder hole bottom side and the cylinder hole opening side of the second liquid passage hole 6b of the cylinder hole 3.

  The plungers 9 and 12 are formed with first recesses 9a and 12a on the bottom side of the cylinder hole and second recesses 9b and 12b on the opening side of the cylinder hole, respectively. A push rod 15 is inserted into the second recess 9b of the first plunger 9, and is provided in the middle of the cylinder axial direction between the first recess 9a of the first plunger 9 and the second recess 12b of the second plunger 12. The first hydraulic pressure chamber 16 communicating with the first output port 4 and the first fluid passage hole 6a is located between the first recess 12a of the second plunger 12 and the bottom wall 3a of the cylinder hole. A second hydraulic pressure chamber 17 communicating with the second output port 5 provided on the side and the second fluid passage hole 6b is defined.

  When the first plunger 9 is in an inoperative state, the large-diameter plunger portion 9c that is in sliding contact with the cylinder hole 3 is located closer to the cylinder hole opening side than the cup seal 11 on the cylinder hole bottom portion side. On the bottom side, a medium-diameter plunger portion 9d having a diameter smaller than that of the large-diameter plunger portion 9c and larger than the inner diameter of the cup seal 11 is opposed to the cup seal 11 on the cylinder hole bottom side of the medium-diameter plunger portion 9d. A small-diameter plunger portion 9e having a smaller diameter than the inner diameter of the cup seal 11 is continuously formed at the position where the large-diameter plunger portion 9e has the same diameter as the large-diameter plunger portion 9c. A portion 9f is formed. Further, one or more small-diameter communication ports 9g penetrating the inside and outside of the intermediate diameter plunger portion 9d are formed in the intermediate diameter plunger portion 9d.

  The cylinder hole 3 is formed with a small-diameter cylinder part 3f on the cylinder hole opening side of the fitting groove 3c of the cup seal 11, and is located on the cylinder hole opening side with respect to the small-diameter cylinder part 3f. A large-diameter cylinder portion 3g communicating with the first liquid passage hole 6a is formed at the opposing position. A small-diameter portion 3h is formed on the bottom side of the fitting groove 3c so that the large-diameter portion 9f of the first plunger 9 is in sliding contact therewith, and a plurality of axial grooves 3i are formed in the small-diameter portion 3h. ing.

  In the non-operating state of the first plunger 9, the first liquid passage hole 6a, the gap between the large diameter plunger portion 9c and the large diameter cylinder portion 3g, the gap between the medium diameter plunger portion 9d and the small diameter cylinder portion 3f, A gap between the small-diameter plunger portion 9e and the inner periphery of the cup seal 11 and the axial groove 3i communicate with each other to form a first liquid passage 18 and to connect the first liquid passage 18 and the communication port 9g. Accordingly, the hydraulic fluid can flow between the reservoir 8 and the first hydraulic chamber 16.

  Further, the large-diameter plunger portion 9c has its tip portion positioned immediately before a predetermined hydraulic pressure is generated in the first hydraulic chamber 16 and the base portion 11a of the cup seal 11 starts to deform toward the small-diameter cylinder portion 3f. It is formed so as to pass through the small diameter cylinder portion 3f.

  Similarly to the first plunger 9, the second plunger 12 also has a large-diameter plunger portion 12c that is in sliding contact with the cylinder hole 3 on the cylinder hole opening side of the cup seal 14 in the non-operating state. Also, on the bottom side of the cylinder hole, the middle diameter plunger portion 12d having a smaller diameter than the large diameter plunger portion 12c and larger than the inner circumference of the cup seal 14 is cupped on the bottom side of the cylinder hole than the middle diameter plunger portion 12d. Small-diameter plunger portions 12e having a smaller diameter than the inner diameter of the cup seal 14 are continuously formed at positions facing the seal 14, and a large-diameter portion 12f is formed on the cylinder hole bottom side of the small-diameter plunger portion 12e. . Further, one or more small-diameter communication ports 12g penetrating the inside and outside of the intermediate diameter plunger portion 12d are formed in the intermediate diameter plunger portion 12d.

  Similarly, the cylinder hole 3 is also provided with a small-diameter cylinder portion 3j on the cylinder hole opening side of the fitting groove 3e of the cup seal 14, and the large-diameter plunger in the non-actuated state on the cylinder hole opening side with respect to the small-diameter cylinder portion 3j. A large-diameter cylinder portion 3k communicating with the second liquid passage hole 6b is formed at a position facing the portion 12c. A small diameter portion 3m is formed on the bottom side of the fitting groove 3e so that the large diameter portion 12f of the second plunger 12 is in sliding contact with the small diameter portion 3m, and a plurality of axial grooves 3n are formed on the small diameter portion 3m. ing.

  In the non-operating state of the second plunger 12, the second fluid passage hole 6b, the gap between the large diameter plunger portion 12c and the large diameter cylinder portion 3k, the gap between the medium diameter plunger portion 12d and the small diameter cylinder portion 3j, and the small diameter The gap between the plunger portion 12e and the inner periphery of the cup seal 14 and the axial groove 3n communicate with each other to form a second liquid passage 19, and through the liquid passage 19 and the communication port 12g, The working fluid can flow between the reservoir 8 and the second hydraulic pressure chamber 17.

  The large-diameter plunger portion 12c generates a predetermined hydraulic pressure in the second hydraulic pressure chamber 17 and immediately before the base portion 14a of the cup seal 14 starts to deform toward the small-diameter cylinder portion 3j, It is formed so as to pass through the small diameter cylinder portion 3j.

  The first hydraulic chamber 16 is inserted into the substantially cylindrical first retainer 20 and the first retainer 20, the head 21a is locked to the tip of the first retainer 20, and the base is first. A first spring mechanism 24 including a first guide pin 21 that is engaged with the engagement plate 22 and a first return spring 23 that urges the first plunger 9 toward the cylinder hole opening side is disposed. Similarly to the first spring mechanism 24 disposed in the first hydraulic chamber 16, the second hydraulic chamber 17 is inserted into the substantially cylindrical second retainer 25 and the second retainer 25. A second guide pin 26 that locks the head portion 26a to the distal end portion of the second retainer 25 and engages the base portion to the second engaging plate 27, and a second member that urges the second plunger 12 toward the cylinder hole opening side. A second spring mechanism 29 having a return spring 28 is disposed.

  When the hydraulic master cylinder 1 formed as described above is not in operation, the first plunger 9 and the second plunger 12 are shown in FIG. 1 by the resilient force of the first and second return springs 23 and 28. As described above, the working fluid can flow between the reservoir 8 and the first hydraulic pressure chamber 16 through the first fluid passage hole 6a through the first fluid passage 18 and the communication port 9g. In addition, the hydraulic fluid can flow between the reservoir 8 and the second hydraulic pressure chamber 17 through the second fluid passage hole 6b through the second fluid passage 19 and the communication port 12g, and operates with a simple structure. The replenishment property of a liquid can be improved.

  In operation, when the push rod 15 pushes the first plunger 9 toward the bottom of the cylinder hole, the first plunger 9 compresses the first return spring 23 in the first hydraulic pressure chamber 16 and moves the cylinder hole 3 toward the bottom. At the same time, the second plunger 12 starts to advance toward the bottom of the cylinder hole.

  On the first hydraulic pressure chamber 16 side shown in FIG. 2, the first plunger 9 advances from the non-actuated state indicated by the solid line, and as shown by the imaginary line in FIG. 2, the medium diameter plunger portion 9d and the small diameter plunger portion 9e are connected. When the connecting inclined portion 9h contacts the inner peripheral portion 11b of the cup seal 11 and the communication between the first fluid pressure chamber 16 and the first fluid passage 18 is interrupted, the fluid moves into the first fluid pressure chamber 16 as it advances further. Generate pressure. The pressurized hydraulic fluid is supplied to one brake system via the output port 4. At this time, since the communication port 9g is formed in the medium diameter plunger portion 9d, it does not slide in contact with the cylinder hole 3 during operation, and there is no possibility of damaging the plunger 9 or the cylinder hole 3.

  Furthermore, when the first plunger 9 is disposed at the non-operating position shown by the solid line in FIG. 2, the vehicle behavior stabilization control system is activated, and the high hydraulic pressure is connected to the output port 4 from the hydraulic circuit. Even when the cup seal 11 is deformed when being supplied to the hydraulic pressure chamber 16 and the gap between the small diameter plunger portion 9e and the inner peripheral portion 11b of the cup seal 11 is blocked, the communication port 9g is connected to the reservoir 8. Since the increase in fluid pressure generated by the vehicle behavior stabilization control system can be suppressed, deformation of the cup seal 11 can be suppressed as much as possible.

  When the hydraulic pressure in the hydraulic chamber 16 increases, the base portion 11a of the cup seal 11 starts to deform toward the small diameter cylinder portion 3f due to the increase in the hydraulic pressure. However, as shown in FIG. Immediately before starting to deform, the tip of the large diameter plunger portion 9c is in a position that has passed through the small diameter cylinder portion 3f, so that even if the base portion 11a of the cup seal 11 is deformed, the cylinder hole 3 and the plunger 9 The durability of the cup seal 11 can be improved without being caught in the gap. Further, when the first plunger 9 moves forward and the inner peripheral portion 11b of the cup seal 11 passes through the communication port 9g as shown in FIG. 4, the cup seal is not restricted by the increase in fluid pressure by the communication port 9g. Even if the base portion 11 a of the eleventh is further deformed, the base portion 11 a is not caught in the gap between the cylinder hole 3 and the plunger 9.

  Although detailed description is omitted, the second hydraulic pressure chamber 17 side also generates hydraulic pressure as the second plunger 12 advances in the same manner as the first hydraulic pressure chamber 16 side. Since the same structure is provided, the same effect can be obtained.

  In the above-described embodiment, the axial groove is formed in the small diameter portion of the cylinder hole where the large diameter portion on the plunger tip side is slidably contacted. However, the present invention is not limited to this, and the axial groove is provided on the plunger side. Further, if the distal end side of the plunger is made small in diameter, there is no need to provide an axial groove. Furthermore, as described above, the present invention is not limited to being applied to a tandem hydraulic master cylinder, but can also be applied to a single hydraulic master cylinder having one plunger.

It is a section front view of a hydraulic master cylinder showing an example of the present invention. It is a principal part expanded sectional view which similarly shows the hydraulic master cylinder from a non-operation state to a hydraulic pressure generation initial state. It is a principal part expanded sectional view which shows the hydraulic master cylinder just before generating a predetermined hydraulic pressure and deform | transforming a cup seal. FIG. 4 is an enlarged cross-sectional view of a main part showing a hydraulic master cylinder in a hydraulic pressure generation state in which a piston is further advanced from the state of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Hydraulic master cylinder, 2 ... Cylinder body, 3 ... Cylinder hole, 3a ... Bottom wall, 3b, 3c, 3d, 3e ... Insertion groove, 4, 5 ... Output port, 6a ... 1st fluid through-hole, 6b 2nd fluid passage hole, 7a, 7b ... Grommet seal, 8 ... Reservoir, 9 ... 1st plunger, 12 ... 2nd plunger, 9a, 12a ... 1st recessed part, 9b, 12b ... 2nd recessed part, 9c, 12c ... Large diameter plunger, 9d, 12d ... Medium diameter plunger, 9e, 12e ... Small diameter plunger, 9f, 12f ... Large diameter, 9g, 12g ... Communication port 10, 11, 13, 14 ... Cup seal, 11a ... Base part, 11b ... Inner peripheral part, 15 ... Push rod, 16 ... First hydraulic pressure chamber, 17 ... Second hydraulic pressure chamber, 18 ... First liquid passage, 19 ... Second liquid passage, 20 ... First retainer, 21 ... first guide pin, 21a ... head, 22 ... first Engaging plate, 23 ... first return spring, 24 ... first spring mechanism, 25 ... second retainer, 26 ... second guide pin, 26a ... head, 27 ... second engaging plate, 28 ... second return spring 29 ... second spring mechanism

Claims (3)

A plunger is slidably inserted through a cup seal fitted in a bottomed cylinder hole formed in the cylinder body, and a hydraulic chamber is defined at the distal end side of the plunger, and the hydraulic chamber is operated. In a hydraulic master cylinder for a vehicle including a reservoir for supplying liquid, the plunger has a large-diameter plunger portion that is in sliding contact with the cylinder hole on the cylinder hole opening side of the cup seal in an inoperative state. An intermediate-diameter plunger portion that is smaller in diameter than the large-diameter plunger portion and closer to the cylinder hole bottom side than the plunger portion, and larger in diameter than the inner diameter of the cup seal, and closer to the cylinder hole bottom side than the intermediate-diameter plunger portion. A small-diameter plunger portion having a smaller diameter than the inner diameter of the cup seal is continuously formed at a position facing the cup seal, and the cylinder hole is fitted to fit the cup seal. A small-diameter cylinder part is provided on the cylinder hole opening side, and a large-diameter cylinder part is provided on the cylinder hole opening side of the small-diameter cylinder part at a position facing the large-diameter plunger part in an inoperative state. Forming a fluid passage hole communicating with the reservoir, and in a non-operating state, a gap between the large diameter plunger portion and the large diameter cylinder portion, a gap between the medium diameter plunger portion and the small diameter cylinder portion, A gap between the small diameter plunger portion and the cup seal is communicated to form a fluid passage, and the fluid pressure chamber and the fluid passage hole are communicated through the fluid passage, so that the cylinder is more than the cup seal of the plunger. A vehicular hydraulic master cylinder, wherein a communication port for communicating the hydraulic chamber and the fluid passage is formed on a hole opening side. The hydraulic master cylinder for a vehicle according to claim 1, wherein the communication port is formed in the medium diameter plunger portion. During operation, the plunger moves forward to the bottom of the cylinder hole, and the inner peripheral side of the cup seal comes into contact with the plunger to generate hydraulic pressure in the hydraulic chamber. 3. The hydraulic master cylinder for a vehicle according to claim 1, wherein the cup seal is formed at a position passing through the small-diameter cylinder before the cup seal is deformed toward the small-diameter cylinder.

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