JP2017227187A - Plunger pump and method of manufacturing plunger pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plunger pump and a method of manufacturing a plunger pump, which can accurately align the central axis of a plunger and the central axis of a seal member.SOLUTION: A plunger pump 101 comprises a pump head 11 with a pump chamber 11a, a plunger 17 with a tip portion 17a reciprocating in the pump chamber 11a, a hold member 14 radially holding the plunger 17 while permitting movement in the axial direction, a seal member 12 having a through hole 12a through which the tip portion 17a is inserted and sealing the pump chamber 11a, a press member 15 pressing the hold member 14 toward the pump head 11 to keep a state in which the central axis of the through hole 12a of the seal member 12 is aligned with the central axis of the plunger 17, and a case 16 accommodating the hold member 14 with a radial play and pressing the press member 15.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a plunger pump and a method for manufacturing the plunger pump, and more particularly to a plunger pump using a member for sealing a pump chamber and a method for manufacturing the plunger pump.

  Conventionally, a plunger pump used for a high performance liquid chromatography apparatus has been developed. As an example of the technology relating to such a plunger pump, for example, Patent Literature 1 (Patent No. 4025646) discloses the following technology. That is, the high-pressure low-capacity pump has a piston and a piston holder, and the piston holder has a first end and a second end disposed on the opposite side of the first end, and The piston is attached to the first end of the piston holder, the ball is arranged at the second end of the piston holder, and further includes a socket provided at one end of the piston drive device, the socket being a base wall A side wall that extends axially from the base wall and surrounds at least a portion of the ball, and a magnet that is held in the base wall and holds the ball in the socket using magnetic force, A spacer is further disposed between the ball and the magnet.

Japanese Patent No. 4025646

  The plunger pump is manufactured by assembling a plurality of components such as a plunger that reciprocates the pump chamber, a motor that reciprocates the plunger, and a seal member that passes the plunger through the pump chamber and seals the pump chamber. For this reason, when the dimensional accuracy of each component varies, or when the assembling accuracy varies between components, the central axes of the components may be displaced from each other.

  For example, when the plunger pump is used in a state where the central axis of the plunger and the central axis of the seal member are shifted from each other, there may be a problem that a part of the seal member is scraped off.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a plunger pump and a method of manufacturing the plunger pump that can accurately match the central axis of the plunger with the central axis of the seal member. It is to be.

  (1) In order to solve the above-described problem, a plunger pump according to an aspect of the present invention includes a pump head including a pump chamber, a plunger whose tip moves back and forth in the pump chamber, and holds the plunger in the radial direction. A holding member that allows axial movement while having a through-hole through which the distal end is inserted, and a seal member that seals the pump chamber, and pressing the holding member toward the pump head The pressing member that maintains the state where the central axis of the through hole of the seal member and the central axis of the plunger coincide with each other, and the case that accommodates the holding member with play in the radial direction and presses the pressing member With.

  With such a configuration, the plunger can be prevented from being eccentric with respect to the seal member, and the central axis of the plunger and the central axis of the seal member can be made to coincide with each other with high accuracy. Thereby, durability of a sealing member can be improved and the discharge accuracy of a plunger pump can be improved.

  When the plunger pump is used in a high performance liquid chromatography apparatus, the plunger performs continuous operation while maintaining a high pressure. In the plunger pump configured as described above, the central axis of the plunger and the central axis of the seal member can be accurately matched, and the central axis of the plunger and the central axis of the seal member are accurately matched. Therefore, it is particularly useful as a plunger pump of a high performance liquid chromatography apparatus.

  Moreover, even if the holding member is in a state of being accommodated in the case, the movement in the radial direction within a certain range is not limited by the case. For this reason, since the freedom degree of the fixing position with respect to the pump head of the holding member by a press member can be raised, the center axis | shaft of the plunger currently hold | maintained at the holding member and the center axis | shaft of a sealing member are matched with higher precision. It is possible to maintain a consistent state with high accuracy.

  (2) More preferably, the pressing member includes an elastic body that presses the holding member toward the pump head from the opposite side of the pump head.

  Thus, by using an elastic body as the pressing member, the holding member can be fixed to the pump head with a simple configuration. Moreover, the operation | work for fixing a holding member with respect to a pump head can be simplified.

  (3) More preferably, the plunger pump further includes an intermediate member with which the pump head is fitted and the holding member abuts on a surface opposite to the pump head.

  Thus, by providing the intermediate member between the pump head and the holding member, the seal member can be replaced by removing the pump head from the intermediate member. That is, since the seal member can be replaced while the holding member is pressed against the intermediate member, it is necessary to align the plunger central axis with the central axis of the seal member after replacement of the seal member. Therefore, the seal member can be easily replaced.

  (4) In order to solve the above problems, a method for manufacturing a plunger pump according to an aspect of the present invention includes a step of allowing movement in an axial direction while holding a plunger in a radial direction using a holding member, Pressing the holding member toward a pump head including a pump chamber, inserting the plunger through a seal member that seals the pump chamber, and inserting the pump head into the pump chamber; Fixing to the accommodated case.

  Thereby, the plunger can be prevented from being eccentric with respect to the seal member, and the central axis of the plunger and the central axis of the seal member can be made to coincide with each other with high accuracy. Thereby, durability of a sealing member can be improved and the discharge accuracy of a plunger pump can be improved.

  When the plunger pump is used in a high performance liquid chromatography apparatus, the plunger performs continuous operation while maintaining a high pressure. The plunger pump configured as described above is particularly useful as a plunger pump of a high-performance liquid chromatography apparatus because the central axis of the plunger and the central axis of the seal member coincide with each other with high accuracy.

  According to the present invention, the central axis of the plunger and the central axis of the seal member can be matched with high accuracy.

FIG. 1 is a perspective view showing the configuration of the plunger pump according to the first embodiment of the present invention. FIG. 2 is an exploded perspective view showing the configuration of the plunger pump according to the first embodiment of the present invention. FIG. 3 is an exploded sectional view showing the configuration of the plunger pump according to the first embodiment of the present invention. FIG. 4 is a perspective view showing the configuration of the ball bush of the plunger pump according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view showing a state in which each of the A member and the B member of the plunger pump according to the first embodiment of the present invention is assembled. FIG. 6 is a cross-sectional view showing a state in which the A member and the B member of the plunger pump according to the first embodiment of the present invention are assembled. FIG. 7 is a perspective view showing the configuration of the plunger pump according to the second embodiment of the present invention. FIG. 8 is an exploded perspective view showing the configuration of the plunger pump according to the second embodiment of the present invention. FIG. 9 is an exploded cross-sectional view showing the configuration of the plunger pump according to the second embodiment of the present invention. FIG. 10 is a cross-sectional view showing a state in which the A member and the B member of the plunger pump according to the second embodiment of the present invention are assembled.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated. Moreover, you may combine arbitrarily at least one part of embodiment described below.

<First Embodiment>
[Constitution]
FIG. 1 is a perspective view showing the configuration of the plunger pump according to the first embodiment of the present invention. FIG. 2 is an exploded perspective view showing the configuration of the plunger pump according to the first embodiment of the present invention.

  1 and 2, the plunger pump 101 includes a pump head 11, a seal member 12, a seal holder 13, a ball bush (holding member) 14, a wave washer (pressing member) 15, and a case 16. A plunger 17, a joint 18, a pole screw 19, and a motor 20.

  Hereinafter, the pump head 11, the seal member 12, and the seal holder 13 are also collectively referred to as “A member”. Further, the ball bush 14, the wave washer 15, the case 16, the plunger 17, the joint 18, the pole screw 19, and the motor 20 are collectively referred to as “B member”.

(Configuration of member A)
FIG. 3 is an exploded sectional view showing the configuration of the plunger pump according to the first embodiment of the present invention.

  Referring to FIG. 3, the pump head 11 has a pump chamber 11a inside. When the inside of the pump chamber 11a is depressurized, the liquid flows into the pump chamber 11a. Further, when the inside of the pump chamber 11a is pressurized, the liquid in the pump chamber 11a flows out of the pump chamber 11a. Further, the pump head 11 is formed so as to be able to fit into the case 16.

  The seal member 12 has, for example, a disk shape having a circular surface 12b, and seals the pump chamber 11a to prevent liquid leakage from the pump chamber 11a. Further, a hole (hereinafter referred to as “through hole 12 a”) having the same size as the outer diameter of the plunger 17 is formed at the center of the seal member 12.

  The seal holder 13 fixes the seal member 12 to the pump head 11 inside the pump head 11. In addition, a hole (hereinafter referred to as “through hole 13 a”) having the same size as the outer diameter of the plunger 17 is formed at the center of the seal holder 13.

(Configuration of B member)
The joint 18 has a cylindrical shape, for example, and a plunger 17 and a pole screw 19 are inserted therein.

  The plunger 17 has, for example, a cylindrical shape, and is fixed to the joint 18 so that its own central axis coincides with the central axis of the joint 18. Further, the tip 17a of the plunger 17 is inserted into the pump chamber 11a of the pump head 11 in a state where the A member and the B member are assembled, and reciprocates in the pump chamber a.

  The pole screw 19 is connected to the motor 20 and converts the rotational motion of the motor 20 into linear motion.

  The wave washer 15 is an annular elastic body, and its own expansion and contraction direction is along the axial direction of the plunger pump 101, that is, the Z-axis direction shown in FIG. 3 (hereinafter simply referred to as “Z-axis direction”). Housed in the case 16.

  The case 16 accommodates the ball bush 14, the wave washer 15, the joint 18, and the pole screw 19 therein. Further, the case 16 is formed so as to be fitted to the motor 20. The case 16 is fitted with the pump head 11 to fix the pump head 11.

  Further, the case 16 is formed so that the inner diameter of the portion that accommodates the ball bush 14 is larger than the outer diameter of the ball bush 14. More specifically, a difference is set between the inner diameter of the case 16 and the outer diameter of the ball bush 14 so that a gap is formed between the inner wall of the case 16 and the outer wall of the ball bush 14. Thereby, the ball bush 14 is accommodated with play in the radial direction with respect to the case 16.

  In addition, a contact surface 16 a with which the wave washer 15 is contacted in a state where the wave washer 15 is accommodated therein is formed inside the case 16.

  The ball bush 14 has a cylindrical shape, and a plunger 17 and a joint 18 are inserted therein. The ball bushing 14 has a plurality of guide portions 14a provided at different positions.

  FIG. 4 is a perspective view showing the configuration of the ball bush of the plunger pump according to the first embodiment of the present invention.

  Referring to FIG. 4, the ball bush 14 has, for example, four guide portions 14a. Each guide portion 14a has a plurality of spheres 30 arranged in an elliptical shape.

  Among the plurality of spheres 30, the plurality of spheres 30 along the elliptical long axis direction are arranged along the Z-axis direction. That is, two rows arranged along the Z-axis direction are connected to form an elliptical guide portion 14a.

  Of the two rows forming the guide portion 14 a, at least a part of each sphere 30 in one row on the central axis side of the ball bush 14 protrudes from the inner wall of the ball bush 14 toward the central axis of the ball bush 14. . Each sphere 30 is rotatable.

  Therefore, in a state where the plunger 17 and the joint 18 are inserted into the ball bush 14, the plurality of spheres 30 come into contact with the joint 18 and hold the plunger 17 and the joint 18 in the radial direction. When the plunger 17 and the joint 18 move in the Z-axis direction, the plurality of spheres 30 circulate while contacting the joint 18 to allow the plunger 17 to move in the axial direction, that is, the Z-axis direction.

  In this manner, the plurality of spheres 30 of the guide portion 14a circulate while contacting the joint 18, whereby the sliding resistance of the plunger 17 and the joint 18 can be reduced, and the plunger 17 and the joint 18 in the Z-axis direction can be reduced. The reciprocating motion can be smoothed.

  Although FIG. 4 shows the ball bush 14 having four guide portions 14a, it is possible to reduce the sliding resistance of the plunger 17 and the joint 18 while holding the plunger 17 and the joint 18 in the radial direction. If so, the ball bushing 14 is not limited to the above configuration. For example, the ball bush 14 may further include a large number or a small number of guide portions 14a.

[Manufacture of plunger pump]
(Assembly of part A)
FIG. 5 is a cross-sectional view showing a state in which each of the A member and the B member of the plunger pump according to the first embodiment of the present invention is assembled.

  With reference to FIG. 5, first, the seal member 12 is accommodated inside the pump head 11 so as to seal the pump chamber 11 a inside the pump head 11. At this time, the surface 12b of the seal member 12 is perpendicular to the Z axis.

  Then, the seal holder 13 is accommodated inside the pump head 11 so that the seal holder 13 covers the seal member 12.

(Assembly of B member)
Next, the pole screw 19 connected to the motor 20 is inserted into the joint 18. Then, the case 16 and the motor 20 are fitted. Thereby, the pole screw 19 and the joint 18 are accommodated inside the case 16.

  Next, the wave washer 15 is accommodated in the case 16 in a direction opposite to the direction in which the motor 20 is fitted. That is, the wave washer 15 is moved along the Z axis while the plunger 17 and the joint 18 are inserted through the hole of the wave washer 15, and the wave washer 15 is brought into contact with the contact surface 16 a of the case 16.

  Next, the ball bush 14 is accommodated in the case 16 in the same direction as the direction in which the wave washer 15 is accommodated. That is, the ball bush 14 is moved along the Z axis while the plunger 17 and the joint 18 are inserted into the hole of the ball bush 14, and the ball bush 14 is brought into contact with the wave washer 15.

  Thereby, for example, the four guide portions 14 a of the ball bush 14 contact the joint 18 in different directions, and hold the plunger 17 and the joint 18 in the radial direction of the plunger 17. At this time, the ball bush 14 is accommodated with play in the radial direction with respect to the case 16. The play between the outer diameter of the ball bush 14 and the inner diameter of the case 16 is 0.1 mm or more, preferably 0.3 mm or more.

(Assembly of A member and B member)
FIG. 6 is a cross-sectional view showing a state in which the A member and the B member of the plunger pump according to the first embodiment of the present invention are assembled.

  Next, referring to FIG. 6, the distal end portion 17 a of the plunger 17 is inserted through the through hole 13 a of the seal holder 13 and the through hole 12 a of the seal member 12. Thereby, the seal holder 13 and the seal member 12 hold | maintain the outer peripheral surface of the front-end | tip part 17a of the plunger 17 so that sliding is possible. Further, the central axis of the through hole 12 a of the seal member 12 and the central axis of the plunger 17 coincide with each other.

  Then, the distal end portion 17 a of the plunger 17 is inserted into the pump chamber 11 a of the pump head 11, and the pump head 11 is fitted into the case 16.

  As described above, when the pump head 11 is fitted into the case 16, the pump head 11 presses the ball bush 14 and the wave washer 15 in the Z-axis direction. Further, the wave washer 15 is bent by the pressure from the pump head 11 and the pressure from the contact surface 16 a of the case 16, and the ball bush 14 is directed toward the pump head 11 from the opposite side of the pump head 11 by its own restoring force. Press.

  Here, since the ball bush 14 is accommodated with play with respect to the case 16, the ball bush 14, the plunger 17, and the joint 18 are not restricted by the case 16 for a certain range of radial movement.

  For this reason, since the freedom degree of the fixing position with respect to the pump head 11 of the ball bush 14 by the wave washer 15 can be raised, the center axis | shaft of the plunger 17 and the center axis | shaft of the sealing member 12 can be matched with higher precision. .

  Further, the ball bushing 14 is accommodated with a play in the radial direction with respect to the case 16, so that, for example, even when there is a variation in dimensional accuracy between the pump head 11 and the case 16, such a variation is caused in the radial direction. Therefore, the central axis of the plunger 17 and the central axis of the seal member 12 can be matched without being affected by the variation.

  That is, the ball bush 14 is pressed from both the pump head 11 and the wave washer 15 while the center axis of the seal member 12 and the center axis of the plunger 17 are kept in agreement with each other. The joint 18 is fixed to the pump head 11.

  In the plunger pump 101 assembled in this manner, when the motor 20 is driven, the plunger 17 and the joint 18 are moved in the Z-axis direction while being held in the radial direction of the plunger 17 by the guide portion 14 a of the ball bush 14. Guided.

  That is, the plunger 17 reciprocates along the Z-axis direction while maintaining a state in which the central axis of the plunger 17 and the central axis of the seal member 12 coincide with each other.

  And if the front-end | tip part 17a of the plunger 17 moves in the direction away from the pump chamber 11a, the inside of the pump chamber 11a will be pressure-reduced and a liquid will flow in into the pump chamber 11a. Further, when the plunger 17 moves in the direction approaching the pump chamber 11a, the inside of the pump chamber 11a is pressurized and the liquid is pushed out from the pump chamber 11a.

  In the plunger pump 101 according to the first embodiment of the present invention, the wave washer 15 presses the ball bush 14 toward the pump head 11 to fix the ball bush 14 to the pump head 11. Explained.

  However, the configuration is not necessarily limited to such a configuration. For example, a screw is used instead of the wave washer 15 as long as the ball bush 14 is pressed against the pump head 11 and fixed to the pump head 11. The ball bush 14 and the pump head 11 may be fixed by using as a pressing member.

  By the way, the plunger pump is manufactured by assembling a plurality of components such as a plunger that reciprocates the pump chamber, a motor that reciprocates the plunger, and a seal member that passes the plunger through the pump chamber and seals the pump chamber. . For this reason, when the dimensional accuracy of each component varies, or when the assembling accuracy varies between components, the central axes of the components may be displaced from each other.

  For example, when the plunger pump is used in a state where the central axis of the plunger and the central axis of the seal member are shifted from each other, there may be a problem that a part of the seal member is scraped off. In particular, when a plunger pump is used in a high-performance liquid chromatography apparatus, the plunger performs continuous operation while maintaining a high pressure, so that a problem such as a part of the seal member peeling off appears prominently. Leakage or lack of liquid discharge may occur and affect measurement accuracy.

  In contrast, in the plunger pump 101 according to the embodiment of the present invention, the ball bush 14 allows movement in the Z-axis direction while holding the plunger 17 in the radial direction. Further, the wave washer 15 presses the ball bush 14 toward the pump head 11 to maintain a state where the central axis of the through-hole 12a of the seal member 12 and the central axis of the plunger 17 coincide.

  With such a configuration, the plunger 17 can be prevented from being eccentric with respect to the seal member 12, and the center axis of the plunger 17 and the center axis of the seal member 12 can be made to coincide with each other with high accuracy. Thereby, the durability of the seal member 12 can be improved, and the discharge accuracy of the plunger pump 101 can be improved.

  When the plunger pump is used in a high performance liquid chromatography apparatus, the plunger performs continuous operation while maintaining a high pressure. In the plunger pump 101 configured as described above, the central axis of the plunger 17 and the central axis of the seal member 12 can be accurately matched, and the central axis of the plunger 17 and the central axis of the seal member 12 are aligned. Since it can maintain a consistent state with high accuracy, it is particularly useful as a plunger pump of a high performance liquid chromatography apparatus.

  Further, in the plunger pump 101 according to the embodiment of the present invention, the case 16 accommodates the ball bush 14 with play in the radial direction and presses the wave washer 15.

  With such a configuration, even when the ball bush 14 is housed in the case 16, the movement of the ball bush 14 in a certain range is not restricted by the case 16. For this reason, since the freedom degree of the fixing position with respect to the pump head 11 of the ball bush 14 by the wave washer 15 can be raised, the center axis | shaft of the plunger 17 currently hold | maintained at the ball bush 14 and the center axis | shaft of the sealing member 12 are made more. Can be matched with high accuracy.

  In the plunger pump 101 according to the embodiment of the present invention, the wave washer 15 that is an elastic body that presses the ball bush 14 toward the pump head 11 from the opposite side of the pump head 11 is used as the pressing member.

  With such a configuration, the ball bush 14 can be fixed to the pump head 11 with a simple configuration. Moreover, the operation | work for fixing the ball bush 14 with respect to the pump head 11 can be simplified.

  In the method for manufacturing the plunger pump according to the embodiment of the present invention, first, the plunger 17 is allowed to move in the axial direction while holding the plunger 17 in the radial direction using the ball bush 14. Then, the ball bush 14 is pressed toward the pump head 11, and the plunger 17 is inserted into the pump chamber 11 a through the seal member 12. Then, the pump head 11 is fixed to the case 16 in which the ball bush 14 is accommodated.

  Thereby, the plunger 17 can be prevented from being eccentric with respect to the seal member 12, and the central axis of the plunger 17 and the central axis of the seal member 12 can be matched with high accuracy. Thereby, the durability of the seal member 12 can be improved, and the discharge accuracy of the plunger pump 101 can be improved.

  When the plunger pump is used in a high performance liquid chromatography apparatus, the plunger performs continuous operation while maintaining a high pressure. The plunger pump 101 configured as described above is particularly useful as a plunger pump of a high-performance liquid chromatography apparatus because the central axis of the plunger 17 and the central axis of the seal member 12 coincide with each other with high accuracy.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Second Embodiment>
In the first embodiment described above, the plunger pump in which the pump head is directly fitted to the case has been described. On the other hand, 2nd Embodiment demonstrates the plunger pump provided with an intermediate member between a pump head and a case. The contents other than those described below are the same as those of the plunger pump according to the first embodiment.

[Constitution]
FIG. 7 is a perspective view showing the configuration of the plunger pump according to the second embodiment of the present invention. FIG. 8 is an exploded perspective view showing the configuration of the plunger pump according to the second embodiment of the present invention.

  7 and 8, the plunger pump 102 according to the second embodiment of the present invention has a pump head 11 and a seal holder as compared with the plunger pump 101 according to the first embodiment of the present invention. Instead of 13, a pump head 51 and a holder (intermediate member) 52 are provided.

  The holder 52 is provided between the pump head 51 and the case 16. The holder 52 is fitted with the pump head 51, and further abuts against the ball bush 14 on the surface opposite to the pump head 51. Thereby, the seal member 12 can be easily replaced by removing the pump head 51 from the holder 52. This will be described in more detail below.

  FIG. 9 is an exploded cross-sectional view showing the configuration of the plunger pump according to the second embodiment of the present invention.

  Referring to FIG. 9, the pump head 51 has a pump chamber 51a inside. When the inside of the pump chamber 51a is depressurized, the liquid flows into the pump chamber 51a. Further, when the inside of the pump chamber 51a is pressurized, the liquid in the pump chamber 51a flows out of the pump chamber 51a. Further, the pump chamber 51a is sealed by the seal member 12.

  The holder 52 is formed to be able to fit with the pump head 51. In addition, a hole (hereinafter referred to as “through hole 52 a”) having the same size as the outer diameter of the plunger 17 is formed inside the holder 52.

  Further, in the holder 52, the plunger 17 and the joint 18 are inserted in a direction opposite to the direction in which the pump head 51 is fitted, and the distal end portion 17a of the plunger 17 is inserted through the through hole 52a.

  Furthermore, the holder 52 is formed so as to be able to fit into the case 16 that accommodates the plunger 17 and the joint 18 in a state where the plunger 17 and the joint 18 are inserted.

[Manufacture of plunger pump]
FIG. 10 is a cross-sectional view showing a state in which the A member and the B member of the plunger pump according to the second embodiment of the present invention are assembled.

  9 and 10, first, the seal member 12 is mounted on the pump head 51 so that the pump chamber 51a inside the pump head 51 is sealed. Then, the pump head 51 in a state where the pump chamber 51 a is sealed is fitted into the holder 52. Thereby, A member is assembled | attached.

  Since the assembly of the B member is the same as the assembly of the B member of the plunger pump 101 according to the first embodiment of the present invention, detailed description thereof will not be repeated here.

  Next, the plunger 17 and the joint 18 are inserted into the holder 52, and the distal end portion 17 a of the plunger 17 is inserted through the through hole 52 a of the holder 52 and the through hole 12 a of the seal member 12. Thereby, the holder 52 and the sealing member 12 hold | maintain the outer peripheral surface of the front-end | tip part 17a of the plunger 17 so that sliding is possible. Further, the central axis of the through hole 12 a of the seal member 12 and the central axis of the plunger 17 coincide with each other.

  Then, the distal end portion 17 a of the plunger 17 is inserted into the pump chamber 51 a of the pump head 51, and the holder 52 is fitted into the case 16.

  Thus, when the holder 52 is fitted to the case 16, the holder 52 comes into contact with the ball bush 14 on the surface opposite to the pump head 51 and presses the ball bush 14 and the wave washer 15 in the Z-axis direction.

  Further, the wave washer 15 is pressed and bent by the holder 52 and presses the ball bush 14 toward the holder 52 from the opposite side of the holder 52 by its own restoring force.

  Here, also in the plunger pump 102 according to the second embodiment of the present invention, the ball bush 14 is accommodated in the case 16 with play, as in the plunger pump 101 according to the first embodiment described above. For this reason, each of the ball bush 14, the plunger 17 and the joint 18 is not restricted by the case 16 for a certain range of radial movement.

  For this reason, since the freedom degree of the fixing position with respect to the pump head 11 of the ball bush 14 by the wave washer 15 can be raised, the center axis | shaft of the plunger 17 and the center axis | shaft of the sealing member 12 can be matched with higher precision. .

  Further, since the ball bush 14 is accommodated in the radial direction with respect to the case 16, for example, even when there is a variation in dimensional accuracy between components, the variation can be absorbed by the radial play. The central axis of the plunger 17 and the central axis of the seal member 12 can be matched without being affected by such variations.

  That is, the ball bush 14 is pressed from both the holder 52 and the wave washer 15 while maintaining the state where the center axis of the seal member 12 and the center axis of the plunger 17 coincide with each other. The joint 18 is fixed to the holder 52.

  In the plunger pump 102 assembled in this way, when the seal member 12 is replaced, for example, the pump head 51 is removed from the holder 52 and the seal member 12 is peeled off from the pump head 51. Then, the pump head 51 equipped with the new seal member 12 is fitted into the holder 52.

  That is, the seal member 12 can be replaced while the ball bush 14 is fixed to the holder 52.

  As described above, in the plunger pump 102 according to the second embodiment of the present invention, the holder 52 is fitted with the pump head 51, and the ball bush 14 abuts on the surface opposite to the pump head 51.

  Thus, by providing the holder 52 between the pump head 51 and the ball bush 14, the seal member 12 can be replaced by removing the pump head 51 from the holder 52. That is, since the seal member 12 can be replaced while keeping the ball bush 14 pressed against the holder 52, the central axis of the plunger 17 and the central axis of the seal member 12 are again aligned after the seal member 12 is replaced. Thus, the seal member 12 can be easily replaced.

  Since other configurations and manufacturing methods are the same as those of the plunger pump 101 according to the first embodiment, detailed description will not be repeated here.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 11,51 Pump head 11a, 51a Pump chamber 12 Seal member 12a Through hole 13 Seal holder 13a Through hole 14 Ball bushing 14a Guide part 15 Wave washer (pressing member)
16 Case 16a Contact surface 17 Plunger 17a Tip 18 Joint 19 Pole screw 20 Motor 30 Sphere 52 Holder (intermediate member)
52a Through hole 101, 102 Plunger pump

Claims (4)

A pump head comprising a pump chamber;
A plunger whose tip reciprocates in the pump chamber;
A holding member that allows movement in the axial direction while holding the plunger in the radial direction;
A seal member having a through-hole through which the tip portion is inserted, and sealing the pump chamber;
A pressing member that maintains a state in which the central axis of the through hole of the seal member and the central axis of the plunger are aligned by pressing the holding member toward the pump head;
A plunger pump comprising: a case for accommodating the holding member in the radial direction with play and pressing the pressing member.   The plunger pump according to claim 1, wherein the pressing member includes an elastic body that presses the holding member toward the pump head from the opposite side of the pump head. The plunger pump further comprises:
The plunger pump according to claim 1 or 2, further comprising an intermediate member with which the pump head is fitted and the holding member abuts on a surface opposite to the pump head. Allowing the movement in the axial direction while holding the plunger in the radial direction using the holding member;
Pressing the holding member toward a pump head including a pump chamber, and inserting the plunger into the pump chamber through a seal member that seals the pump chamber;
And a step of fixing the pump head to a case containing the holding member.

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