WO2021241403A1

WO2021241403A1 - Reciprocating piston pump

Info

Publication number: WO2021241403A1
Application number: PCT/JP2021/019214
Authority: WO
Inventors: 寿朗中西
Original assignee: 株式会社丸山製作所
Priority date: 2020-05-27
Filing date: 2021-05-20
Publication date: 2021-12-02
Also published as: JP2021188537A; JP7469955B2; TW202212701A

Abstract

This reciprocating piston pump comprises: a piston rod, the rear end side of which in the axial line direction is coupled to a drive unit, and which reciprocates inside a cylinder; piston packing which has a water absorption valve seat fitted on and fixed to the piston rod and having a through-hole communicating with the front and rear in the axial line direction, and packing formed from an elastic body, held on the outer peripheral side of the water absorption valve seat, and makes sliding contact with the inner peripheral surface of the cylinder; a water absorption valve which is cylindrical and externally inserted to the piston rod so as to be movable in the axial line direction, which is positioned on the front side of the water absorption valve seat in the axial direction, and which opens/closes the through-hole by being unseated from or seated on the water absorption valve seat; and a pressing member which presses the water absorption valve such that the water absorption valve is seated on the water absorption valve seat.

Description

Reciprocating piston pump

This disclosure relates to a reciprocating piston pump.

Patent Document 1 discloses a reciprocating piston pump in which a piston reciprocates in a cylinder. This reciprocating piston pump has a crank shaft pivotally supported by a crankcase and a piston rod connected to the crank shaft. A cylindrical piston packing (piston) that reciprocates in the cylinder is connected to the tip of the piston rod. On the outer peripheral side of the piston packing, a packing that is in sliding contact with the cylinder is provided in an annular shape.

In the piston packing, a plurality of through holes penetrating in the front-rear direction in the axial direction are bored along the circumferential direction on the inner peripheral side of the packing. A water absorption valve seat is formed at the end facing the front side in the axial direction. At the tip of the piston rod, a cylindrical water absorption valve (valve body) is arranged so as to be movable in the axial direction on the front side in the axial direction from the piston packing. Further, at the tip of the piston rod, a cylindrical stopper is fixed on the front side in the axial direction from the water absorption valve. A spring is arranged between the stopper and the water absorption valve to press the water absorption valve so that it sits on the water absorption valve seat.

During the water absorption process of the reciprocating piston pump, the piston rod moves backward in the axial direction, the water absorption valve separates from the water absorption valve seat against the pressing force of the spring, and the liquid used from the water absorption port passes through. It flows forward from the piston packing in the axial direction through the hole and the gap between the water absorption valve and the water absorption valve seat.

When switching to the discharge process, the piston rod moves forward in the axial direction, and the water absorption valve sits on the water absorption valve seat and closes the through hole. Then, the liquid used in front of the piston packing in the axial direction is pressurized, and the discharge valve arranged in front of the stopper in the axial direction is opened. The working liquid is discharged to the outside from the discharge port via the discharge valve.

Jitsukaisho 61-181881

In the above-mentioned reciprocating piston pump, it is desired that when the water absorption valve leaves the water absorption valve seat during the water absorption process, the flow of the working liquid from the through hole of the water absorption valve seat is smooth and efficient. There is. Further, it is required to alleviate the impact when the water absorption valve sits on the water absorption valve seat during the discharge process. In addition, when the water absorption valve is seated on the water absorption valve seat during the discharge process, the water film is cut by the contact between the flat surfaces, so that a vacuum phenomenon occurs between the water absorption valve and the water absorption valve seat and the sticking phenomenon occurs. This occurs, and when the water absorption valve leaves the water absorption valve seat during the water absorption process, pulsation occurs and noise increases.

According to the present disclosure, when the water absorption valve is released from the seat, the flow of the working liquid from the through hole of the water absorption valve seat can be smoothly and efficiently flowed, and the impact when the water absorption valve is seated can be alleviated. It is an object of the present invention to provide a reciprocating piston pump capable of preventing the occurrence of pulsation when the water absorption valve leaves the seat and reducing noise.

In the reciprocating piston pump according to the present disclosure, the rear end side in the axial direction is connected to the drive unit (9), and the piston rod (7) reciprocates in the cylinder (3) and the piston rod (7) having a cylindrical shape. A water-absorbing valve seat (22b) that is fitted and fixed to the outside and has a plurality of through holes (27) that communicate with each other in the front-rear direction in the axial direction, and is held in an annular shape on the outer peripheral side of the water-absorbing valve seat (22b) to form a cylinder (cylinder). 3) A piston packing (22) provided with a packing (22a) made of an elastic body that is in sliding contact with the inner peripheral surface, and a cylindrical piston rod (7) that is externally movable along the axial direction. A water absorption valve (21) that is located on the front side of the water absorption valve seat (22b) in the axial direction and opens and closes a plurality of through holes (27) by leaving or sitting on the water absorption valve seat (22b). Each of the plurality of through holes (27) of the water absorption valve seat (22b) is provided with a pressing member (23) for pressing the water absorption valve (21) so that the valve (21) is seated on the water absorption valve seat (22b). Is spaced at equal intervals along the circumferential direction, and a recessed groove (28) recessed rearward in the axial direction is provided in a plurality of through holes (27) on the front surface of the water absorption valve seat (22b) in the axial direction. ) Are provided in an annular shape so as to connect them.

According to such a reciprocating piston pump (100), in the water absorption valve seat (22b), a plurality of holes (27) are provided so as to be spaced apart at equal intervals along the circumferential direction and communicate with each other in the axial direction. Further, a concave groove (28) connecting the front ends of the plurality of through holes (27) in the axial direction in an annular shape is provided on the front surface in the axial direction. Therefore, when the water absorption valve (21) is separated from the water absorption valve seat (22b), the liquid used from the plurality of through holes (27) of the water absorption valve seat (22b) goes around the through holes (27). The concave groove (28) connected in the direction once gathers in a ring shape and hits the water absorption valve (21), and the water absorption valve (21) can be disengaged with a uniform force, so that the flow of the liquid used is smooth. The liquid used is efficiently flowed. Further, since the water absorption valve (21) can be separated from the seat with a uniform force in this way, the water absorption valve (21) is prevented from tilting. Further, since the liquid used stays in the recessed groove (28) connecting the front end of the through hole (27) of the water absorption valve seat (22b) in the circumferential direction, the water absorption valve (21) becomes the water absorption valve seat (22b). The impact when sitting is mitigated. Further, the concave groove (28) provided on the front surface of the water absorption valve seat (22b) in the axial direction prevents the water absorption valve (21) from cutting the water film when seated on the water absorption valve seat (22b). The vacuum phenomenon between the water absorption valve (21) and the water absorption valve seat (22b) is alleviated and the sticking phenomenon is suppressed. As a result, when the water absorption valve (21) is separated from the water absorption valve seat (22b), the generation of pulsation is prevented and the noise is reduced.

The through hole (27) in the example may be an elongated hole forming an arc shape in the axial direction.

As described above, according to the present disclosure, when the water absorption valve is released from the seat, the flow of the working liquid from the through hole of the water absorption valve seat can be smoothly and efficiently flowed, and the water absorption valve can be prevented from tilting. It is possible to provide a reciprocating piston pump capable of alleviating the impact when the water absorption valve is seated, preventing the occurrence of pulsation when the water absorption valve is released from the seat, and reducing noise.

It is a vertical sectional view which shows an example reciprocating piston pump. It is a vertical sectional view which shows the piston packing in FIG. It is a front view of the piston packing in FIG. 1. It is operation | movement explanatory drawing of the main part at the time of a water absorption process of an example reciprocating piston pump. It is operation | movement explanatory drawing of the main part at the time of a discharge process of an example reciprocating piston pump.

Hereinafter, an example of the reciprocating piston pump according to the present disclosure will be described with reference to the attached drawings.

The reciprocating piston pump of the exemplary embodiment is used for equipment such as a power atomizer and the like. As the liquid used for the reciprocating piston pump, various liquids are used depending on the application.

As shown in FIG. 1, the reciprocating piston pump 100 is roughly provided with a crankcase 1, a water absorption side manifold 2, a cylinder pipe (cylinder) 3, and a discharge side manifold 4 connected in this order from the right side to the left side in the drawing. ing. Inside the crank case 1, the crank shaft 5 pivotally supported by the crank case 1, the connecting rod 6 rotatably connected to the crank shaft 5, and the rear end portion of the piston rod 7 rotatably connected to the connecting rod 6 are connected. Piston pins 8 and the like are arranged. The crank shaft 5, the connecting rod 6, the piston pin 8, and the like constitute a drive unit 9 for reciprocating the piston rod 7. The piston rod 7 is reciprocally arranged inside the crankcase 1 to the cylinder pipe 3.

1 and 5 show a state in which the piston rod 7 is located at the top dead center in the discharge process in which the piston rod 7 moves forward in the axial direction due to the rotation of the crank shaft 5. FIG. 4 shows a state in which the piston rod 7 is located at the bottom dead center in the water absorption process in which the piston rod 7 moves rearward in the axial direction.

The crankcase 1 is filled with lubricating oil. An oil seal 10 that is in sliding contact with the piston rod 7 is arranged at a position in the crankcase 1 through which the piston rod 7 passes. The oil seal 10 prevents the lubricating oil in the crankcase 1 from leaking to the water absorption side manifold 2. A seal packing 11 that is in sliding contact with the piston rod 7 is disposed in the water absorption side manifold 2. The seal packing 11 prevents the liquid used on the water absorption side manifold 2 side from leaking to the oil seal 10 side. The water absorption side manifold 2 is provided with a water absorption port 15 for sucking the working liquid into the inside.

A discharge valve 17 is provided at the tip of the discharge side manifold 4 in front of the cylinder pipe 3. The discharge valve 17 opens and closes the flow path, and when opened, the liquid used is discharged to the discharge port 16. The discharge side manifold 4 is provided with a pressure regulating valve 18 for adjusting the pressure of the liquid to be discharged. Further, the discharge side manifold 4 is provided with an air chamber 19 for buffering the pulsation of the discharged liquid to be used.

Further, a water absorption valve mechanism 20 is provided in the cylinder pipe 3. The water absorption valve mechanism 20 reciprocates in the axial direction together with the piston rod 7. The water absorption valve mechanism 20 is opened so that the liquid used is absorbed from the water absorption port 15 toward the discharge valve 17 during the water absorption process in which the piston rod 7 moves rearward in the axial direction. The water absorption valve mechanism 20 is closed so as to pressurize the liquid used on the discharge valve 17 side during the discharge process in which the piston rod 7 moves forward in the axial direction.

As shown in FIGS. 4 and 5, the water absorption valve mechanism 20 mainly includes a water absorption valve 21, a piston packing 22, and a spring 23. The piston packing 22 includes a packing 22a and a water absorption valve seat 22b that are in sliding contact with the inner peripheral surface of the cylinder pipe 3. The spring 23 as a pressing member presses the water absorption valve 21 so as to be seated on the water absorption valve seat 22b. The water absorption valve mechanism 20 further includes a collar 24, a washer 25, and a hexagon nut 26.

The water absorption valve 21 is a disk having a through hole for passing the collar 24 in the center. The water absorption valve 21 is arranged on the front side in the axial direction from the piston packing 22. The collar 24 is a cylinder having a through hole in the center for passing the piston rod 7. The outer peripheral surface of the rear end portion of the collar 24 in the axial direction is reduced in diameter. The water absorption valve 21 is extrapolated to the reduced diameter portion 29. The water absorption valve 21 is movable along the axial direction in the reduced diameter portion 29.

As shown in FIG. 2, the water absorption valve seat 22b constituting the piston packing 22 has a substantially cylindrical shape, and has a through hole in the center for passing the piston rod 7. The water absorption valve 21 is detached or seated on the water absorption valve seat 22b. That is, the water absorption valve 21 can move between a state of being seated and a state of being seated with respect to the water absorption valve seat 22b. The water absorption valve seat 22b is arranged on the rear side of the water absorption valve 21 and the collar 24 in the axial direction (see FIGS. 4 and 5). As shown in FIGS. 2 and 3, the water absorption valve seat 22b has a plurality of through holes 27 that communicate with each other in the front-back direction in the axial direction. That is, the plurality of through holes 27 penetrate the water absorption valve seat 22b along the axial direction of the water absorption valve seat 22b. Each of the plurality of through holes 27 is arranged at equal intervals along the circumferential direction. An example through hole 27 is an elongated hole forming an arc shape with the axis as the center when viewed from the axial direction. In the illustrated example, four through holes 27 are shown. An annular recessed groove 28, which is recessed rearward in the axial direction, is provided on the front surface of the water absorption valve seat 22b in the axial direction. An axial front end of the through hole 27 is arranged on the bottom surface (right side of FIG. 2) of the recessed groove 28. That is, the recessed groove 28 connects the front ends in the axial direction of the plurality of through holes 27 arranged along the circumferential direction.

The packing 22a constituting the piston packing 22 is formed in an annular shape from an elastic body such as rubber. The packing 22a is pushed into an annular groove provided on the outer periphery of the water absorption valve seat 22b to be accommodated and held.

Then, as shown in FIGS. 4 and 5, from the tip end side of the piston rod 7, the piston packing 22, the collar 24 having the water absorption valve 21 extrapolated to the reduced diameter portion 29, and the washer 25 are fitted in this order. A spring 23 is interposed between the water absorption valve 21 and the washer 25. A hexagon nut 26 is fastened to the male screw 30 formed at the tip of the piston rod 7 by screwing. The rear end surface of the water absorption valve seat 22b of the piston packing 22 in the axial direction is abutted against the expanded step portion 31 of the piston rod 7. The piston packing 22, the collar 24, and the washer 25 are sandwiched (fixed) between the stepped portion 31 and the hexagon nut 26.

During the discharge process shown in FIGS. 1 and 5, the water absorption valve 21 is pressed by a spring 23 interposed between the water absorption valve 21 and the washer 25. As a result, the water absorption valve 21 is seated on the water absorption valve seat 22b. In this state, the through hole 27 and the recessed groove 28 are closed.

When the crank shaft 5 is rotationally driven, the piston rod 7 reciprocates in the cylinder pipe 3. The piston rod 7 repeats a water absorption step of moving from top dead center to bottom dead center (see FIG. 4) and a discharge step of moving from bottom dead center to top dead center (see FIG. 5).

Here, when the discharge process is switched to the water absorption process, the piston rod 7 moves backward in the axial direction. As shown in FIG. 4, the water absorption valve 21 separates from the water absorption valve seat 22b against the pressing force of the spring 23. In this state, a gap is formed between the water absorption valve 21 and the water absorption valve seat 22b (the water absorption valve 21 of the water absorption valve mechanism 20 is opened), and the through hole 27 is opened. In the state where the through hole 27 is open, the liquid used from the water suction port 15 passes through the through hole 27 and the recessed groove 28 and is absorbed forward in the axial direction of the piston packing 22 as shown by the flow of the arrow. NS.

As described above, when the water absorption valve 21 is separated from the water absorption valve seat 22b, the liquid used that comes out from the plurality of through holes 27 of the water absorption valve seat 22b is a concave groove that connects the through holes 27 in the circumferential direction. It is once gathered in a ring shape by 28 and hits the water absorption valve 21. Therefore, the water absorption valve 21 can be separated from the seat with a uniform force, the flow of the working liquid can be smoothed, and the working liquid can be efficiently flowed (the water absorption efficiency can be improved). Further, since the water absorption valve 21 can be separated from the seat with a uniform force in this way, it is possible to prevent the water absorption valve 21 from tilting.

Further, since the through hole 27 is a long hole having an arc shape in the axial direction, the above-mentioned action / effect can be further enhanced as compared with the circular hole.

On the other hand, when the water absorption process shifts to the discharge process, the piston rod 7 moves forward in the axial direction. In this state, as shown in FIG. 5, the water absorption valve 21 is seated on the water absorption valve seat 22b by the pressing force of the spring 23. That is, the water absorption valve 21 closes the through hole 27 and the recessed groove 28 (the water absorption valve 21 of the water absorption valve mechanism 20 is closed), and the through hole 27 is closed.

When the water absorption valve 21 is seated on the water absorption valve seat 22b, the liquid used stays in the recessed groove 28 connecting the front end of the through hole 27 of the water absorption valve seat 22b in the circumferential direction, so that the liquid used acts as a cushion and is seated. The impact of can be mitigated.

Further, the recessed groove 28 provided on the front surface of the water absorption valve seat 22b prevents the water absorption valve 21 from cutting the water film when seated on the water absorption valve seat 22b. That is, surface contact is reduced. Therefore, the vacuum phenomenon between the water absorption valve 21 and the water absorption valve seat 22b is alleviated. That is, the phenomenon of sticking of the water absorption valve 21 to the water absorption valve seat 22b is suppressed.

Further, in synchronization with the movement of the piston rod 7 forward in the axial direction, the packing 22a moves forward while sliding in contact with the inner peripheral surface of the cylinder pipe 3. As a result, the water pressure increases, and the water absorption valve 21 is pressed against the water absorption valve seat 22b with a stronger pressing force. By improving the sealing property, the flow of the working liquid is surely blocked.

When the piston packing 22 moves forward in the axial direction, the liquid used in front of the piston packing 22 opens the discharge valve 17 and is discharged to the outside from the discharge port 16 as shown by the flow of the arrow.

After that, the discharge process is switched to the water absorption process, and the piston rod 7 moves backward in the axial direction. As shown in FIG. 4, the water absorption valve 21 is separated from the water absorption valve seat 22b. As described above, the sticking phenomenon of the water absorption valve 21 to the water absorption valve seat 22b is suppressed by the recessed groove 28. Therefore, it is possible to prevent the occurrence of pulsation when the water absorption valve 21 leaves the water absorption valve seat 22b, and it is possible to reduce noise.

In one example, since the liquid used flows in one direction, the water absorption efficiency is high and the energy saving of the reciprocating piston pump itself can be achieved. Further, since the flow of the working liquid can be brought close to a straight line, the flow of the working liquid becomes smooth and the water absorption efficiency can be further improved.

Since the piston packing 22 moves in synchronization with the movement of the piston rod 7, pulsation can be prevented and stable pump performance can be exhibited.

The structure is such that the water absorption valve 21 is opened and closed by the movable water absorption valve 21 leaving or sitting on the fixed water absorption valve seat 22b, and the weight of the water absorption valve 21 is smaller than that of the water absorption valve seat 22b. The impact force when opening and closing the valve 21 can be reduced, and noise can be reduced. Further, by forming the water absorption valve 21 from the resin, a large low noise effect can be obtained.

Since the water absorption valve 21 is forcibly opened and closed according to the movement of the piston rod 7, it can be opened and closed reliably with little loss.

Further, unlike the forced valve type piston pump described in Japanese Patent Application Laid-Open No. 2014-224469, the water absorption valve does not have a configuration in which the water absorption valve comes into contact with the stopper and the water absorption valve seat, respectively, when the water absorption valve is opened and closed. Since the number of contacts is once when the water absorption valve seat 22b is seated, noise reduction can be achieved.

As described above, the present disclosure is not limited to the above embodiment. For example, the packing 22a may be other than rubber as long as it is an elastic body.

Further, although the water absorption valve 21 is pressed by the spring 23 to be seated on the water absorption valve seat 22b, the water absorption valve 21 may be pressed by a pressing member other than the spring 23.

Further, in the above embodiment, an example in which the reciprocating piston pump 100 is applied to a power sprayer is described, but for fine mist cooling and mist where cavitation generation due to fresh water and noise due to striking noise are worrisome. The same can be applied to other reciprocating piston pumps such as reciprocating piston pumps.

3 ... Cylinder pipe (cylinder), 7 ... Piston rod, 21 ... Water absorption valve, 22 ... Piston packing, 22a ... Packing, 22b ... Water absorption valve seat, 23 ... Spring (pressing member), 27 ... Through hole, 28 ... Concave Groove, 100 ... Reciprocating piston pump.

Claims

The piston rod (7), whose rear end side in the axial direction is connected to the drive unit (9) and reciprocates in the cylinder (3),
A water absorption valve seat (22b) having a cylindrical shape, fitted to the piston rod (7), and fixed, and having a plurality of through holes (27) communicating in the front-rear direction in the axial direction, and the water absorption valve seat ( A piston packing (22) provided with a packing (22a) made of an elastic body held in an annular shape on the outer peripheral side of the cylinder (3) and slidably in contact with the inner peripheral surface of the cylinder (3).
It forms a cylinder and is extrapolated to the piston rod (7) so as to be movable along the axial direction, and is located on the front side of the water absorption valve seat (22b) in the axial direction to the water absorption valve seat (22b). On the other hand, a water absorption valve (21) that opens and closes the plurality of through holes (27) by leaving or sitting on the water absorption valve (21).
A reciprocating piston pump including a pressing member (23) that presses the water absorption valve (21) so that the water absorption valve (21) sits on the water absorption valve seat (22b).
Each of the plurality of through holes (27) of the water absorption valve seat (22b) is spaced apart at equal intervals along the circumferential direction.
On the front surface of the water absorption valve seat (22b) in the axial direction, a concave groove (28) recessed rearward in the axial direction is provided in an annular shape so as to connect the plurality of through holes (27). Reciprocating piston pump.
The reciprocating piston pump according to claim 1, wherein the plurality of through holes (27) are elongated holes forming an arc shape when viewed from the axial direction.