JP2004360468A - Plunger pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plunger pump capable of increasing efficiencies of manufacturing operation and assembly operation and reducing costs by integrally forming a retainer with a seal member. <P>SOLUTION: This plunger pump comprises a pump casing 5 fixed into a pump hole 2 in a housing 1, plungers 6 slidably fitted into the pump casing, a pressure chamber 13 formed between the pump casing and the plungers and compressing a fluid flowing from an inflow passage 3 thereinto according to the slidable movement of the plungers, and a first check valve 16 allowing the fluid to flow into the pressure chamber side thereof. The first check valve comprises a ball valve element 17 opening and closing the opening end 12a of an axial hole 12 and a retainer 19 elastically holding the lower end part of a valve spring 18 energizing the ball valve element in the closing direction. A spring seat 21 at the upper end part of the retainer and a seal member 22 sealing the pressure chamber are formed integrally with each other with a synthetic resin material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plunger pump applied to, for example, an antilock brake device for controlling a vehicle brake fluid pressure.
[0002]
[Prior art]
As this type of conventional plunger pump, the one described in the following patent document applied to an antilock brake device is known.
[0003]
In brief, the plunger pump includes a cylindrical pump casing housed and fixed in a pump hole formed in a housing, a plurality of plungers slidably provided inside the pump casing, A pressure chamber formed between the pump casing and the plunger to compress the brake fluid supplied from the flow passage; a first check valve provided in the pressure chamber; and one end of the plunger. An annular seal member made of rubber, which is fitted to the small diameter portion and seals the pressure chamber while sliding on the inner peripheral surface of the pump casing.
[0004]
At the inner end of the pump casing, a plug body provided with a second check valve that communicates with the outflow passage is fixed in a liquid-tight manner, while the plunger moves inward in the inner axial direction. An axial hole constituting a part of the passage is formed facing the pressure chamber, and is urged in the eccentric rotor cam direction by a spring force of a highly rigid coil spring.
[0005]
The first check valve includes a ball valve body that opens and closes an open end facing the pressure chamber of the axial hole, a spring that biases the ball valve body in a closing direction, and a metal bowl that holds the spring. A retainer, and one end of the coil spring is elastically held by a flange portion at one end of the retainer.
[0006]
Then, when the eccentric rotor cam rotates with the rotation of the electric motor, each plunger whose tip abuts on the eccentric rotor cam slides forward and backward in the pump casing to perform a pumping operation, and the brake fluid flowing into the axial hole is discharged. The ball valve element of the first check valve is introduced into the pressure chamber while being pushed open against the spring force of the spring, and is fed to the outflow passage via the second check valve.
[0007]
[Patent Document 1] Japanese Patent Application Laid-Open No. 11-257245
[Problems to be solved by the invention]
However, in the conventional plunger pump, the retainer and the seal member of the first check valve are formed separately from different materials. For this reason, the number of parts is increased, leading to a reduction in manufacturing work efficiency and assembling work efficiency, as well as complicating parts management and increasing costs.
[0009]
The present invention has been devised in view of the above-mentioned conventional technical problems, and integrally forms a seal member and a retainer with the same synthetic resin material to improve the efficiency of a manufacturing operation and an assembling operation. It is intended to provide a plunger pump that can be envisaged.
[0010]
[Means for Solving the Problems]
In the invention according to the first aspect, the check valve that opens and closes the opening end of the inflow passage facing the pressure chamber and opens and closes the opening end only allows fluid to flow only into the pressure chamber. A valve body, and a retainer for holding a spring member for urging the valve body in a closing direction, wherein the retainer and a seal member for sealing the pressure chamber are integrally formed of a synthetic resin material. It is characterized by.
[0011]
According to the present invention, since the retainer and the seal member are integrated with the synthetic resin material, the number of parts can be reduced. As a result, the efficiency of the manufacturing operation and the efficiency of the assembling operation can be improved, and the parts management can be facilitated. Therefore, the cost can be reduced.
[0012]
Particularly, since the retainer and the seal member can be molded simultaneously and together by molding the synthetic resin material, the efficiency of the manufacturing operation is further improved.
[0013]
According to the invention described in claim 2, the retainer has a spring seat on an outer peripheral portion for elastically holding an end of a second spring member for urging the plunger in the advance direction. The seal member is formed integrally, and an annular seal lip is provided at an outer end of the seal member on the pressure chamber side.
[0014]
According to the present invention, a concave portion is formed on the inner peripheral side by the seal lip formed on the outer peripheral edge of the spring seat, that is, since the seal lip has an annularly protruding shape. This facilitates positioning of the second spring member during assembly.
[0015]
In addition, by making the end of the spring resiliently held in the recess, sliding contact between the end of the second spring member and the inner peripheral surface of the pump casing via the seal lip can be avoided. As a result, it is possible to prevent the inner peripheral surface of the pump casing from being worn and the sliding noise from being generated.
[0016]
Further, by forming the seal lip, it is possible to reduce the surface pressure of the entire outer peripheral surface of the seal member against the inner peripheral surface of the pump casing. As a result, the smooth sliding property of the plunger can always be ensured.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a plunger pump according to the present invention will be described in detail with reference to the drawings. In this embodiment, a plunger pump applied to an anti-lock brake device is shown, and FIG. 1 shows a part of the plunger pump in an enlarged manner.
[0018]
That is, in this plunger pump, a plurality of pump holes 2 are formed in a radial direction in a housing 1 made of an aluminum alloy provided with a brake fluid pressure control mechanism such as an electromagnetic valve. It is connected to each wheel cylinder via a reservoir tank (not shown) via the inflow passage 3, and is connected to a master cylinder via an outflow passage 4.
[0019]
The pump hole 2 is formed to have a step diameter, and has a small diameter portion 2a at one end, a middle diameter portion 2b having an inflow passage 3 opened, and a large diameter portion communicating with an outflow passage 4 at the other end. 2c, and a substantially bottomed cylindrical pump casing 5 is disposed in a part 2d of the middle diameter portion 2b, which protrudes inward, and a plunger 6 is slidable in the pump casing 5. The distal end 6a of the plunger 6 slides from the small-diameter portion 2a to the working chamber 1a in the housing 1 so as to be freely retractable. The plug 7 fixed to the end of the pump casing 4 is housed inside the large diameter portion 2c.
[0020]
In the pump casing 5, a filter member 8 for filtering the brake fluid supplied from the inflow passage 3 is press-fitted and fixed from above to an upper end portion 5a having a small diameter in the figure, and a center of a large-diameter bottom portion 5b on the lower end side. A passage hole 9 is formed in the through hole. The filter member 8 is formed in a substantially cylindrical shape, and a plurality of filtration meshes 8a are integrally provided at equal intervals in a circumferential direction.
[0021]
The plunger 6 is formed in a substantially columnar shape, and a distal end surface of the distal end portion 6a is brought into sliding contact with an outer peripheral surface of the eccentric rotor cam 10 rotated by an electric motor to apply a sliding force. A radial hole 11 communicating with the inflow passage 4 via the filter member 8 is formed in the inner radial direction of the portion 6a side in the radial direction, and one end is opened in the radial hole 11 in the internal axial direction, An axial hole 12 whose other end opening 12a faces a pressure chamber 13 described later is formed. Further, the rear end portion 6b of the plunger 6 is formed with a two-step small-diameter fitting portion 6c. The radial hole 11 and the axial hole 12 constitute a part of the inflow passage 3.
[0022]
A seal ring 14 made of rubber, for example, for sealing between the small-diameter hole 2a and the annular fitting groove formed on the outer periphery of the tip 6a of the plunger 6 is fitted. The seal ring 14 has a small-width projection 14a integrally formed at the center in the width direction of the outer peripheral surface and in sliding contact with the inner peripheral surface of the small-diameter portion 2a. To ensure good slidability.
[0023]
A pressure chamber 13 is formed inside the pump casing 5 between the lower end portion 6b of the plunger 6 and a second chamber for urging the plunger 6 in a direction in which the plunger 6 protrudes. And a first check valve 16 that opens and closes the other end opening 12a of the axial hole 12 is disposed.
[0024]
The first check valve 16 includes a ball valve body 17 that is detachably seated on a valve seat provided at the other end opening 12a of the axial hole 12, and a valve spring that is a spring member that urges the ball valve body 17 in a closing direction. And a retainer 19 for holding the valve spring 18.
[0025]
The retainer 19 is integrally formed of a synthetic resin material by an injection molding machine or the like, and as shown in FIGS. 2 to 5, a substantially bowl-shaped holding portion 20 for holding a lower end portion of the valve spring 18; It is mainly constituted by a substantially annular flange-shaped spring seat 21 provided integrally with the upper end edge of the portion 20 and elastically holding the upper end of the coil spring 15.
[0026]
As shown in FIG. 3 to FIG. 5, the holding portion 20 has four notches 20 a formed at 90-degree positions in the circumferential direction vertically long along the axial direction, and the notches 20 a define the inside of the pressure chamber 13. A protrusion that allows the brake fluid to freely move inside, restricts the maximum downward movement of the ball valve element 17 on the inner surface of the bottom wall 20b, and restricts the free radial movement of the lower end of the valve spring 18. 20c are formed.
[0027]
The spring seat 21 is formed in a relatively thick annular shape, and its outer peripheral portion is configured as a seal member 22. This outer peripheral surface 22 a is formed in a tapered shape expanding toward the holding portion 20. The entire part abuts against the inner peripheral surface 5c of the pump casing 5 to seal the inside of the pressure chamber 13. In the spring seat 21, a concave annular groove 24 for holding the upper end of the coil spring 15 in FIG. 1 is formed on the end face on the holding section 20 side, and the annular groove 24 is located. A seal lip 23 integral with the seal member 22 is formed on the outer peripheral portion.
[0028]
The seal lip 22 is formed in a substantially thin annular shape by an annular groove 24 and is capable of expanding and contracting. 5 is brought into pressure contact with the inner peripheral surface to exhibit sealing performance.
[0029]
As shown in FIG. 1, the plug 7 has a lower end portion which is formed by caulking the outer end of the large diameter portion 2c of the pump hole 2, that is, the hole edge 1a of the pump hole 2 of the housing 1. And a first check valve 26 for opening and closing a downstream opening end of the passage hole 9 communicating with the pressure chamber 13 is disposed in a valve groove 25 formed substantially at the center of the upper surface.
[0030]
The second check valve 26 is a ball valve body 27 which is seated on and off a valve seat formed at the edge of the passage hole 9 to open and close the passage hole 9, and biases the ball valve body 27 in the closing direction. The ball valve 27 opens the passage hole 9 against a spring force of the spring 28 by a predetermined pressure in the pressure chamber 13. The passage hole 9 communicates with the outflow passage 4 via a disc-shaped passage groove 29 formed on the upper surface of the plug 7.
[0031]
Therefore, according to this embodiment, the plunger 6 slides inside the pump casing 5 with the rotation of the eccentric rotor cam 10, so that a pumping action is performed, and the brake flowing into the inflow passage 3 from the wheel-cylinder side (reservoir tank). The liquid passes through the radial hole 11 and the axial hole 12 through the filter member 8 to open the lower end opening 12 a of the ball valve element 17 of the first check valve 16 against the spring force of the valve spring 18. As a result, the brake fluid is filled in the pressure chamber 13, and further, the ball valve body 27 of the second check valve 26 is pushed open from the pressure chamber 13, and is discharged from the passage groove 29 to the outflow passage 4, and the master valve is discharged. Reflux to the cylinder side. As a result, the brake fluid in the reservoir tank can be quickly returned to the master cylinder side by a normal pump action.
[0032]
Further, according to this embodiment, since the retainer 19 and the seal member 21 are integrated with a synthetic resin material, the number of parts can be reduced. As a result, the efficiency of the manufacturing operation and the efficiency of the assembling operation can be improved, and the parts management can be facilitated. Therefore, cost can be reduced.
[0033]
In particular, since the retainer 19 and the seal member 21 can be molded simultaneously and together by molding of a synthetic resin material, the production work efficiency is further improved.
[0034]
In addition, since a concave annular groove 24 is formed in the spring seat 21 and the end of the coil spring 15 is fitted and held therein, the positioning of the coil spring 15 at the time of assembly becomes easy, and the sealing is performed. By the lip 23, the sliding contact between the outer peripheral surface of the end of the coil spring 15 and the inner peripheral surface 5c of the pump casing 5 can be avoided. For this reason, it is possible to prevent wear of the inner peripheral surface 5c of the pump casing and generation of sliding contact noise.
[0035]
Further, since the outer peripheral surface 22a of the seal member 22 is formed in a tapered shape and the seal lip 23 is formed in the largest diameter portion, the seal lip 23 mainly contacts the inner peripheral surface 5c of the pump casing 5. For this reason, it is possible to reduce the surface pressure of the entire outer peripheral surface 22a of the seal member 22 against the inner peripheral surface 5c of the pump casing. As a result, the plunger 6 can always have smooth sliding properties.
[0036]
The present invention is not limited to the configuration of each of the above embodiments, but can be applied to devices and actuators other than the antilock brake device as an application target of the plunger pump.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a plunger pump according to the present invention.
FIG. 2 is a bottom view of the retainer provided in the embodiment.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
FIG. 4 is a sectional view taken along line BB of FIG. 2;
FIG. 5 is a plan view of the retainer.
[Explanation of symbols]
Reference Signs List 1 housing 2 pump hole 3 inflow passage 4 outflow passage 5 pump casing 6 plunger 11 radial hole 12 axial hole 13 pressure chamber 15 coil spring (second spring member)
16 first check valve 18 valve spring (spring member)
19 ... Retainer 21 ... Spring seat 22 ... Seal member 22a ... Outer peripheral surface 23 ... Seal lip 24 ... Ring groove

Claims (2)

A pump casing fixed in the pump hole of the housing;
A plunger slidably provided in the pump casing;
A pressure chamber formed between the pump casing and the plunger, in which the fluid flowing in from the inflow passage due to the sliding of the plunger is compressed;
A check valve that opens and closes an open end of the inflow passage facing the pressure chamber, and allows only fluid to flow into the pressure chamber.
A seal member is provided between the pump casing and the plunger to seal the pressure chamber,
The check valve has a valve body that opens and closes the open end, and a retainer that holds a spring member that urges the valve body in a closing direction. The retainer and the seal member are integrally formed of a synthetic resin material. A plunger pump characterized in that it is formed in a plunger. The retainer has a spring seat on an outer peripheral portion for resiliently holding an end of a second spring member for urging the plunger in the advance direction. The seal member is formed integrally with the spring seat, and the seal is formed. The plunger pump according to claim 1, wherein an annular seal lip is provided at an outer end of the member on the pressure chamber side.

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