JP2008286083A - Plunger pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plunger pump capable of miniaturizing in an axial direction, reducing the number of components, and improving assembly efficiency of the plunger. <P>SOLUTION: The plunger pump 1 is provided with a cylinder 1 formed in a pump body 3, and the plunger 30 slidably installed in the cylinder 11, defining a pump chamber 20 in the cylinder at one end thereof and butting on an eccentric cam 2 (drive means) at another end thereof, and sucks brake fluid into the pump chamber 20 by reciprocating motion of the plunger 30 in the cylinder 11. A seal groove 31 (circumferential groove) is formed on an outer circumference surface of the plunger 30, an annular seal member 32 is fitted in the seal groove 31, and the shape at one end side and the shape at another end side of a center position in an axial direction of the plunger are same. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plunger pump that discharges liquid by reciprocating a plunger in an axial direction.

2. Description of the Related Art Conventionally, a plunger pump that discharges liquid by reciprocating a plunger (also referred to as a piston) in an axial direction by an eccentric cam is known.
As shown in FIG. 4, the plunger pump 100 has a cylinder 111 formed in the pump body 3 and a slidably mounted in the cylinder 111, and one end of the plunger pump 100 has a pump chamber 120 in the cylinder 111. The other end includes a plunger 130 that is in contact with the cam surface 2a of the eccentric cam 2 (see, for example, Patent Document 1).
The cylinder 111 includes a chamber portion 113a and a sliding portion 113b of the mounting hole 3a formed in the pump body 3, and a bottomed cylindrical bottom member 112 fitted in the chamber portion 113a of the mounting hole 3a. The plunger 130 is configured to slide in the axial direction within a sliding portion 113b formed on the other end side of the chamber portion 113a.
In the plunger pump 100, when the plunger 130 moves to the eccentric cam 2 side, liquid is sucked into the pump chamber 120 from the suction port 114, and the plunger 130 moves to the pump chamber 120 side by being pushed by the eccentric cam 2. Sometimes, the liquid in the pump chamber 120 is discharged from a discharge port (not shown) through the discharge chamber 180.

  Further, in the above-described conventional plunger pump 100, one end of the plunger 130 protrudes into the pump chamber 120, and one end of the plunger 130 is between the outer peripheral surface of the plunger 130 and the inner peripheral surface of the sliding portion 113b. An annular sealing member 132 for sealing the liquid is tightly fitted.

Japanese Patent Laying-Open No. 2005-030365 (paragraph 0003, FIG. 4)

In the pump body 3 having the plunger pump 100 having the above-described structure, it is desired to reduce the size of the pump body 3 by reducing the plunger pump 100 in the axial direction (left-right direction in FIG. 4).
In the conventional plunger pump 100 described above, since the pump chamber 120 is enlarged in the axial direction so that the seal member 132 is accommodated in the pump chamber 120, the plunger pump 100 is enlarged in the axial direction.
The plunger pump 100 can be made smaller by shortening the sliding portion 113b in the axial direction corresponding to the length of the pump chamber 120 extending in the axial direction to accommodate the seal member 132. Since the sliding portion 113b supporting the plunger 130 is shortened, when the plunger 130 is reciprocated in the cylinder 111, the plunger 130 is liable to be shaken and becomes unstable.

  There is also a plunger pump in which the plunger is divided in the axial direction and the seal member is sandwiched between them, so that the seal member is disposed outside the pump chamber without shortening the sliding portion in the axial direction (patent) In this configuration, since the number of parts of the plunger pump increases, the assembly work of the plunger pump becomes complicated and the manufacturing cost of the plunger pump increases. .

  Therefore, the present invention provides a plunger pump that solves the above-described problems, can be reduced in the axial direction, can reduce the number of parts, and can further improve the assembly efficiency of the plunger. Is an issue.

  In order to solve the above-described problems, the present invention provides a cylinder formed in a pump body, a slidably mounted cylinder, one end defining a pump chamber in the cylinder, and the other end serving as a driving means. A plunger pump that abuts on the outer peripheral surface of the plunger, wherein the plunger reciprocates in the axial direction in the cylinder to discharge the liquid sucked into the pump chamber from the suction port through the discharge port. A circumferential groove is formed, and an annular seal member is fitted in the circumferential groove, and the shape of the plunger is the same on the one end side and the other end side with respect to the axial center position. .

In this configuration, since the seal member for sealing the space between the outer peripheral surface of the plunger and the inner peripheral surface of the cylinder is disposed outside the pump chamber, the pump chamber can be made smaller in the axial direction. The plunger pump can be made smaller in the axial direction.
Moreover, since it is not necessary to shorten the distance which a plunger and a cylinder slide, a plunger can be operated stably.
In addition, the seal member is configured to be fitted in the circumferential groove formed on the outer peripheral surface of the plunger, and since the number of parts of the plunger pump is small, the plunger pump can be easily assembled and the manufacturing cost of the plunger pump Can be cheaper.
Furthermore, since the shape of the plunger on the one end side and the shape on the other end side are the same with respect to the axial center position, and the direction of the axial direction is not set, when the plunger is assembled in the cylinder, Therefore, it is not necessary to pay attention to this, and the assembly efficiency of the plunger can be improved.

  In the above-described plunger pump, the circumferential groove can be configured to be formed at the center position in the axial direction of the plunger.

  In this configuration, since the shape of the plunger is simplified, the manufacturing cost of the plunger pump can be reduced.

According to the plunger pump of the present invention, since the seal member is disposed outside the pump chamber, the plunger pump can be reduced in the axial direction, and the pump body can be reduced in size.
Moreover, since it is not necessary to shorten the distance which a plunger and a cylinder slide, a plunger can be operated stably.
Moreover, since the number of parts of the plunger pump is reduced, the plunger pump can be easily assembled and the manufacturing cost of the plunger pump can be reduced.
Further, since the plunger is not set in the axial direction, it is not necessary to pay attention to the direction of the plunger when the plunger is assembled in the cylinder, and the efficiency of assembling the plunger can be improved.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In the present embodiment, a plunger pump used as a hydraulic pressure generator of a brake hydraulic pressure control device mounted on a vehicle such as an automobile will be described as an example.
In the following description, one end side corresponds to the left side in FIG. 1, and the other end side corresponds to the right side in FIG.

[Overall configuration of plunger pump]
As shown in FIG. 1, the plunger pump 1 has a cylinder 11 formed in the pump body 3 and is slidably mounted in the cylinder 11. One end defines a pump chamber 20 in the cylinder 11, and the like. The end is a plunger 30 that is in contact with the eccentric cam 2, a return spring 40 that presses the plunger 30 toward the eccentric cam 2, a suction valve 50 that allows only the brake fluid to flow into the pump chamber 20, and a pump. And a discharge valve 60 that allows only the brake fluid to flow out of the chamber 20.
The plunger pump 1 is configured to discharge the brake fluid sucked into the pump chamber 20 when the plunger 30 reciprocates in the cylinder 11 in the axial direction.

(Structure of pump body)
The pump body 3 is a metal block mounted on a vehicle. A plurality of oil passages (not shown) are formed in the pump body 3, and a mounting hole 3a having a circular cross section into which the plunger pump 1 is inserted is formed. Is provided.
The other end of the mounting hole 3 a communicates with a storage hole 3 b having a circular cross section that is recessed in the outer surface of the pump body 3. In the present embodiment, the attachment hole 3a extends in the left-right direction in FIG. 1, and the storage hole 3b extends in a direction perpendicular to the attachment hole 3a (perpendicular to the paper surface).
The attachment hole 3a communicates with a suction passage 3c serving as a flow passage for brake fluid supplied to the plunger pump 1 and a discharge passage 3d serving as a flow passage for brake fluid discharged from the plunger pump 1. The suction path 3c communicates with a substantially intermediate position in the axial direction of the mounting hole 3a, and the discharge path 3d communicates with the mounting hole 3a on one end side of the suction path 3c.

The suction path 3c is a flow path that connects the mounting hole 3a and the reservoir 3f, and brake fluid is supplied into the mounting hole 3a through the suction path 3c.
The reservoir 3f is a space formed in the pump body 3, and a piston 4 is slidably mounted therein. The piston 4 is urged toward the suction path 3c by a spring member 4a provided in the reservoir 3f.

A suction valve 50 that is a check valve that allows only the brake fluid to flow into the mounting hole 3a is provided in the suction passage 3c.
The suction valve 50 includes a cylindrical member 54 in which the suction hole 55 penetrates in the axial direction of the suction passage 3c, a suction valve body 51 that seals the opening of the suction hole 55 on the mounting hole 3a side, and the suction valve body. 51, a retainer 52 that is disposed at the end of the cylindrical member 54 on the pump chamber 20 side, and is housed in the retainer 52. The suction valve body 51 is placed on the opening side of the suction hole 55. And a spring member 53 to be pressed.

The cylindrical member 54 is a metal member through which the suction hole 55 penetrates along the central axis, and is fitted in the suction passage 3c. A valve seat 55a having a funnel-like diameter is formed on the opening edge of the suction hole 55 on the pump chamber 20 side.
The suction valve body 51 is a metal sphere, and seals the opening of the suction hole 55 by contacting the valve seat 55 a of the suction hole 55.
The retainer 52 is a metal cup-shaped lid, and is fitted on the end of the cylindrical member 54 on the mounting hole 3a side with the concave side facing the cylindrical member 54, whereby a suction valve body is provided. 51 is covered. In addition, a plurality of communication holes 52a are formed in the retainer 52, and the inside of the retainer 52 communicates with the inside of the suction passage 3c.
The spring member 53 is a coil spring disposed in a compressed state between the inner surface of the retainer 52 and the suction valve body 51.

  In the suction valve 50, when the value obtained by subtracting the brake fluid pressure on the mounting hole 3a side from the brake fluid pressure on the reservoir 3f side in the suction passage 3c is equal to or higher than the valve opening pressure (the urging force of the spring member 53). In addition, the suction valve body 51 is configured to be opened by being separated from the valve seat 55a against the urging force of the spring member 53.

(Configuration of eccentric cam)
An eccentric cam 2 that is a driving means of the plunger pump 1 is provided on a rotating shaft of an electric motor (not shown) attached to the pump body 3 and is housed in a housing hole 3 b formed in the pump body 3. Yes. The center position of the eccentric cam 2 is eccentric with respect to the axis center A of the rotating shaft, and the eccentric cam 2 is configured to rotate around the axis center A of the rotating shaft as the rotating shaft rotates. Yes.

(Cap configuration)
A bottomed cylindrical cap 70 is fitted into one end of the mounting hole 3a. The cap 70 is a metal member, and a hollow portion 71 formed inside is open on the other end side. The cavity 71 is a space that constitutes the discharge chamber 80.
A seal groove 72 is formed on the entire outer periphery of the cap 70. A resin seal member 73 is fitted in the seal groove 72, and the seal member 73 provides a liquid-tight seal between the outer peripheral surface of the cap 70 and the inner peripheral surface of the mounting hole 3a.
Further, on the inner peripheral surface of the mounting hole 3a, a retaining groove 3e is formed on the entire circumference in the vicinity of the opening on one end side. An outer peripheral side of a metal C-shaped clip 74 is fitted into the retaining groove 3e, and the outer peripheral edge of the cap 70 disposed on the other end side of the clip 74 in the mounting hole 3a is the clip 74. The cap 70 is locked in the mounting hole 3a by abutting on the inner peripheral side.

(Cylinder configuration)
The cylinder 11 is formed in the pump body 3, and a plunger 30 is slidably mounted therein. The cylinder 11 includes a chamber portion 13a and a sliding portion 13b of the mounting hole 3a, and a metal bottom member 12 fitted in the chamber portion 13a.

The bottom member 12 constitutes the bottom portion of the cylinder 11 and is a bottomed cylindrical member fitted inside the chamber portion 13a of the mounting hole 3a. The cavity 12a formed inside the bottom member 12 opens to the other end side.
Further, a discharge hole 12c having a circular cross section passes through the center position of the bottom 12b of the bottom member 12, and the diameter of the discharge hole 12c on one end side (discharge chamber 80 side) is increased in a funnel shape. The valve seat 12d is formed.

  In addition, the bottom member 12 and the cap 70 are spaced apart in the axial direction, and a gap between the bottom portion 12b of the bottom member 12 and the peripheral wall portion of the cap 70 is for discharging brake fluid from the plunger pump 1. A discharge port 15 is formed. The discharge port 15 communicates with the discharge path 3d of the pump body 3, and allows the brake fluid to be discharged from the discharge chamber 80 in the cap 70 to the discharge path 3d.

The chamber portion 13 a is formed at a substantially intermediate position in the axial direction in the mounting hole 3 a, and the internal space constitutes the pump chamber 20. A suction port 14 communicating with the suction passage 3c of the pump body 3 is formed in the chamber portion 13a, and the brake fluid can be supplied from the pump body 3 into the cylinder 11 (pump chamber 20).
The sliding portion 13b is formed in the attachment hole 3a on the other end side with respect to the chamber portion 13a. One end communicates with the chamber portion 13a and the other end communicates with the storage hole 3b. A plunger 30 is slidably attached to the sliding portion 13b.

(Composition of plunger)
The plunger 30 is a metal or resin rod-like member mounted in the sliding portion 13b of the cylinder 11, and one end protrudes into the chamber portion 13a and the other end protrudes into the storage hole 3b. The plunger 30 has a circular cross section, and is configured such that when the plunger 30 is reciprocated in the axial direction in the cylinder 11, the outer peripheral surface of the plunger 30 slides on the inner peripheral surface of the sliding portion 13b. Yes.

On the outer peripheral surface of the plunger 30, a seal groove 31 is formed on the entire circumference at the axial center position. A resin seal member 32 is fitted in the seal groove 31, and the seal member 32 provides a liquid-tight seal between the outer peripheral surface of the plunger 30 and the inner peripheral surface of the sliding portion 13 b.
The plunger 30 is obtained by cutting a rod-shaped member with a predetermined length, and forming a circumferential groove (seal groove 31) on the outer peripheral surface at the center position in the axial direction of the cut member. The shape on one end side and the shape on the other end side from the center position in the direction are the same. That is, the outer shape of the plunger 30 is symmetrical with respect to a virtual reference plane located at the center in the axial direction, with the axial direction being the normal direction.

One end of the plunger 30 projects into the chamber portion 13 a and defines a pump chamber 20 in the cylinder 11.
Further, one end of the plunger 30 is covered with a lid-like engagement member 33. A flange portion 33 a is formed on the entire periphery of the opening edge of the engagement member 33, and the flange portion 33 a protrudes from the entire periphery of the outer peripheral surface on one end side of the plunger 30.

  The other end surface of the plunger 30 protrudes from the sliding portion 13 b into the accommodation hole 3 b and is in contact with the cam surface 2 a of the eccentric cam 2. Since the eccentric cam 2 rotates eccentrically around the axis center A of a rotating shaft (not shown), when the rotating shaft is rotated, the plunger 30 is pushed by the eccentric cam 2 from the position of FIG. Will move in the axial direction.

(Return spring configuration)
The return spring 40 is a coil spring in which one end 41 is in contact with the bottom member 12 and the other end 42 is engaged with the outer peripheral surface of the plunger 30, and is disposed in the pump chamber 20 in a compressed state. Specifically, one end 41 of the return spring 40 contacts the inner surface of the bottom portion 12 b of the bottom member 12, and the other end 42 of the return spring 40 is a flange portion 33 a of the engagement member 33 attached to one end of the plunger 30. Abut.

  The return spring 40 presses the plunger 30 toward the eccentric cam 2, and after the plunger 30 moves to one end side by being pushed by the eccentric cam 2, the cam surface 2 a of the eccentric cam 2 is displaced in a direction away from the plunger 30. When done, the plunger 30 is moved to the eccentric cam 2 side. That is, the plunger 30 moves in the axial direction toward the eccentric cam 2 by the pressing force from the return spring 40. Thereby, the state where the other end surface of the plunger 30 is in contact with the cam surface 2a of the eccentric cam 2 is maintained.

(Composition of discharge valve)
The discharge valve 60 is a check valve that allows only brake fluid to flow into the discharge chamber 80, and is provided at the opening on the discharge chamber 80 side of the discharge hole 12 c formed in the bottom member 12.
The discharge valve 60 includes a discharge valve body 61 that seals the opening of the discharge hole 12c on the discharge chamber 80 side, a retainer 62 that is held by the bottom member 12 so as to cover the discharge valve body 61, and the retainer 62 And a spring member 63 that presses the discharge valve body 61 toward the opening of the discharge hole 12c.

The discharge valve body 61 is a metal sphere, and seals the opening of the discharge hole 12c by contacting the valve seat 12d of the discharge hole 12c.
The retainer 62 is a metal cup-shaped lid, and covers the discharge valve body 61 by being externally fitted to one end of the bottom member 12. In addition, a plurality of communication holes 62 a are formed in the retainer 62, and the retainer 62 and the discharge chamber 80 communicate with each other. Further, a holding portion 62 b that is recessed toward the inside of the retainer 62 is formed at the center position of the bottom portion of the retainer 62.
The spring member 63 is a coil spring disposed in a compressed state between the inner surface of the retainer 62 and the discharge valve body 61, and the holding portion 62 b of the retainer 62 is inserted into the center hole of the spring member 63. The spring member 63 is positioned in the retainer 62.

  In the discharge valve 60, when the value obtained by subtracting the brake fluid pressure in the discharge chamber 80 from the brake fluid pressure in the pump chamber 20 is equal to or higher than the valve opening pressure (the urging force of the spring member 63), the spring member The discharge valve body 61 is configured to open by separating from the valve seat 12d against the urging force of 63.

[Operation of plunger pump]
Operation | movement of the plunger pump 1 comprised as mentioned above is demonstrated.
In the state where the pump chamber 20 in the cylinder 11 of the plunger pump 1 and the discharge chamber 80 are filled with the brake fluid, the plunger 30 is pushed by the rotating eccentric cam 2 so that the plunger 30 is directed from the state of FIG. When the forward movement is performed in the axial direction, the volume of the pump chamber 20 decreases and the hydraulic pressure of the brake fluid in the pump chamber 20 increases.
As a result, the value obtained when the brake fluid pressure in the discharge chamber 80 is subtracted from the brake fluid pressure in the pump chamber 20 becomes equal to or higher than the valve opening pressure of the discharge valve 60, so that the discharge valve 60 opens and the pump chamber The brake fluid in 20 flows into the discharge chamber 80. Then, the brake fluid is discharged from the discharge chamber 80 through the discharge port 15 to the discharge passage 3d of the pump body 3.

Subsequently, after the plunger 30 moves to the one end side (top dead center) and the volume of the pump chamber 20 becomes minimum, the cam surface 2a of the rotating eccentric cam 2 is displaced in a direction away from the plunger 30. Become. At this time, the plunger 30 moves back in the axial direction toward the other end side by the pressing force from the return spring 40, and the volume of the pump chamber 20 increases.
As the volume of the pump chamber 20 increases, the inside of the pump chamber 20 is in a negative pressure state, and the suction valve 50 has a value obtained by subtracting the brake fluid pressure in the pump chamber 20 from the brake fluid pressure in the reservoir 3f. Since the pressure exceeds the valve opening pressure of the valve 50, the suction valve 50 opens, and the brake fluid in the suction passage 3c flows into the pump chamber 20 in the mounting hole 3a through the suction port 14.

Then, after the plunger 30 is moved back to the other end side (bottom dead center) and the volume of the pump chamber 20 is maximized, the plunger 30 is pushed by the cam surface 2a of the rotating eccentric cam 2 and travels again. As in the case of the forward operation described above, the brake fluid in the pump chamber 20 is pressurized by the plunger 30 and flows into the discharge chamber 80 and is discharged from the discharge port 15 to the discharge passage 3d.
As described above, the plunger pump 1 is configured such that the brake fluid sucked into the pump chamber 20 from the suction port 14 is discharged from the discharge port 15 when the plunger 30 reciprocates in the axial direction in the cylinder 11. .

[Effects of plunger pump]
In the plunger pump 1 of the present embodiment, a seal member 32 for liquid-tightly sealing between the outer peripheral surface of the plunger 30 and the inner peripheral surface of the cylinder 11 (sliding portion 13b) is disposed outside the pump chamber 20. Since the pump chamber 20 can be reduced in the axial direction, the plunger pump 1 can be reduced in the axial direction, and the pump body 3 can be reduced in size.
Further, since it is not necessary to shorten the sliding portion 13b on which the plunger 30 slides in the axial direction, the plunger 30 can be stably reciprocated in the cylinder 11.

  Further, since the seal member 32 is configured to be fitted into the seal groove 31 formed on the entire outer periphery of the plunger 30, the number of parts of the plunger pump 1 is reduced, and the plunger pump 1 can be easily assembled. In addition, the manufacturing cost of the plunger pump 1 can be reduced.

  Furthermore, since the shape of the plunger 30 on the one end side and the shape on the other end side are the same with respect to the axial center position, and the axial direction is not set, the plunger 30 is assembled in the cylinder 11. In addition, it is not necessary to pay attention to the direction of the plunger 30, and the assembly efficiency of the plunger 30 can be improved.

  Further, the seal groove 31 formed in the plunger 30 is formed at the center position in the axial direction of the plunger 30 and the shape of the plunger 30 is simplified, so that the manufacturing cost of the plunger pump 1 can be reduced.

[Other Embodiments]
The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the spirit of the present invention.

  For example, in the present embodiment, as shown in FIG. 1, the cap 70 that closes one end of the mounting hole 3 a and the bottom member 12 that forms the bottom of the cylinder 11 are configured as separate members. A pump housing 90 in which a cap 91 that closes one end of the mounting hole 3a and a bottom 92 that constitutes the bottom of the cylinder 11 are integrally formed can be used as in the plunger pump 1A shown.

  In the pump housing 90, a discharge chamber 80 is formed at a substantially intermediate position in the axial direction. Also, a plurality of discharge passages 93 penetrating from the discharge chamber 80 to the outer peripheral surface of the pump housing 90 are formed, and the opening on the outer peripheral surface side of each discharge passage 93 is a discharge port 15 communicating with the discharge passage 3d of the pump body 3. It has become.

In the pump housing 90, a hollow portion 92 a constituting the pump chamber 20 is formed in a bottom portion 92 formed on the other end side from the discharge chamber 80, and the hollow portion 92 a communicates with the discharge chamber 80. A through hole 94 is formed.
A cylindrical member 95 is fitted in the through hole 94, and a discharge hole 95a passes through the cylindrical member 95 along the central axis.

  In the plunger pump 1 </ b> A shown in FIG. 2, when the discharge valve 60 is assembled in the discharge chamber 80, first, the spring member 63 and the discharge valve body 61 are in a state in which the cylindrical member 95 is not fitted in the through hole 94. In the discharge chamber 80. Thereafter, the cylindrical member 95 is press-fitted into the through-hole 94 from the cavity 92 a side and the plunger 30 side of the through-hole 94 is caulked, whereby the spring member 63 is placed between the inner surface of the discharge chamber 80 and the discharge valve body 61. While being disposed in a compressed state, the discharge valve body 61 seals the opening of the discharge hole 95a.

  In the plunger pump 1A shown in FIG. 2, the cap 91 that closes one end of the mounting hole 3a and the bottom 92 that constitutes the bottom of the cylinder 11 are integrally formed, and it is not necessary to provide a retainer on the discharge valve 60. Therefore, the number of parts of the plunger pump 1A is reduced, the plunger pump 1A can be easily assembled, and the manufacturing cost of the plunger pump 1 can be reduced.

  Moreover, in the plunger pump 1 of this embodiment, as shown in FIG. 1, the seal groove 31 is formed at the center position in the axial direction of the plunger 30, but the plunger 30 is at one end side of the center position in the axial direction. The shape and the shape on the other end side need only be the same. For example, seal grooves may be provided at target positions on one end side and the other end side with respect to the axial center position of the plunger 30. In this configuration, since the sealing members are disposed twice, the liquid tightness between the outer peripheral surface of the plunger 30 and the inner peripheral surface of the sliding portion 13b can be enhanced.

  Moreover, in the plunger pump 1 of this embodiment, as shown in FIG. 1, the discharge valve 60 is arrange | positioned in the discharge chamber 80, but as shown in FIG.3 (b), one end surface of the bottom member 12 is shown. A recess 12e can be formed in the recess 12e, and the discharge valve 60A can be accommodated in the recess 12e.

The discharge valve body 61 of the discharge valve 60A is in contact with the valve seat 12d of the discharge hole 12c formed on the bottom surface of the recess 12e of the bottom member 12.
The retainer 64 of the discharge valve 60A is a circular lid disposed at the opening of the recess 12e, and the discharge valve body 61 in the recess 12e is covered by the retainer 64.
Further, an opening 64a is formed at the center position of the retainer 64, and the inside of the retainer 64 and the discharge chamber 80 are communicated with each other by the opening 64a.
Further, the retainer 64 is formed with tongue-shaped spring portions 64b and 64b protruding inward of the opening 64a (see FIG. 3A). The spring portion 64b is inclined toward the bottom side of the recess 12e as it goes toward the tip side. And the front-end | tip part of each spring part 64b and 64b is contact | abutting to the discharge valve body 61, and is pressing the discharge valve body 61 to the opening part side of the discharge hole 12c.

In the discharge valve 60A shown in FIG. 3B, it is not necessary to secure a space for accommodating the discharge valve 60A in the discharge chamber 80, the discharge chamber 80 can be made smaller in the axial direction, and the plunger pump can be moved in the axial direction. Therefore, the pump body can be reduced in size.
Further, since it is not necessary to dispose the spring member in the retainer 64, the number of parts of the plunger pump is reduced, the plunger pump can be easily assembled, and the manufacturing cost of the plunger pump can be reduced.

  In the discharge valve 60A shown in FIGS. 3 (a) and 3 (b), the discharge valve body 61 is pressed by the two tongue-shaped spring portions 64b and 64b, but FIGS. 3 (c) and 3 (d). As shown in the discharge valve 60B shown in FIG. 6, the integral tongue-shaped spring portion 64b may protrude inward of the opening 64a of the retainer 64. In this configuration, the retainer 62 has a simple configuration, and the retainer 62 can be processed. Since it becomes simple, the manufacturing cost of the discharge valve 60B can be reduced.

Further, as shown in FIGS. 3E and 3F, the discharge valve 60 </ b> C that restricts the movement of the discharge valve body 61 is set by narrowing the distance between the inner surface of the retainer 65 and the discharge valve body 61. It can also be used.
In the discharge valve 60C, when the brake fluid pressure in the pump chamber 20 is larger than the brake fluid pressure in the discharge chamber 80, the discharge valve body 61 is pushed up to the discharge chamber 80 side by the pressure from the pump chamber 20 side. To open the valve. When the brake fluid pressure in the discharge chamber 80 is larger than the brake fluid pressure in the pump chamber 20, the discharge valve body 61 discharges due to the pressure acting on the discharge valve body 61 from the discharge chamber 80 through the communication hole 65 a. The valve seat 12d is pressed against the valve seat 12d of the hole 12c to be in a closed state.
In this configuration, there is no need to house a spring member for pressing the discharge valve body 61 toward the opening of the discharge hole 12c in the retainer 65, or to form a spring portion on the retainer 65. While being able to assemble easily, the manufacturing cost of the discharge valve 60C can be reduced.

  Further, as another embodiment of the discharge valve 60 shown in FIG. 1, the discharge valves 60A, 60B, and 60C shown in FIGS. 3A to 3F have been described, but the configuration of the discharge valves 60A, 60B, and 60C is described. Can also be applied to the suction valve 50 shown in FIG.

  In the present embodiment, a plunger pump used as a hydraulic pressure generator of a brake hydraulic pressure control device mounted on a vehicle such as an automobile has been described as an example. However, the plunger pump of the present invention is limited to a vehicle brake system. However, it is applicable to various hydraulic paths.

It is side sectional drawing which showed the plunger pump of this embodiment. It is the sectional side view which showed the plunger pump of other embodiment. It is the figure which showed the discharge valve of other embodiment, (a) is the figure which looked at the discharge valve provided with the retainer in which the two spring parts were formed from the discharge chamber side, (b) is the sectional side view, (C) is the figure which looked at the discharge valve provided with the retainer in which the integral spring part was formed from the discharge chamber side, (d) is the sectional side view, (e) is the discharge valve of the structure which does not use a spring member. The figure seen from the discharge chamber side, (f) is the sectional side view. It is the sectional side view which showed the conventional plunger pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plunger pump 2 Eccentric cam 3 Pump body 3a Mounting hole 3b Storage hole 3c Suction path 3d Discharge path 3f Reservoir 11 Cylinder 12 Bottom member 12c Discharge hole 13a Chamber part 13b Sliding part 14 Suction port 15 Discharge port 20 Pump chamber 30 Plunger 31 Seal groove 32 Seal member 50 Suction valve 51 Suction valve body 52 Retainer 53 Spring member 60 Discharge valve 61 Discharge valve body 62 Retainer 63 Spring member 70 Cap 80 Discharge chamber

Claims (2)

A cylinder formed in the pump body;
A plunger slidably mounted in the cylinder, one end defining a pump chamber in the cylinder, and the other end contacting a drive means;
A plunger pump that discharges the liquid sucked into the pump chamber from the suction port through the discharge port by reciprocating the plunger in the axial direction in the cylinder,
A circumferential groove is formed on the outer peripheral surface of the plunger, and an annular seal member is fitted in the circumferential groove,
The plunger pump is characterized in that the shape on one end side and the shape on the other end side are the same as the axial center position.   The plunger pump according to claim 1, wherein the circumferential groove is formed at a center position in an axial direction of the plunger.

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