JP2022160856A - reciprocating pump - Google Patents

Abstract

To provide a reciprocating pump that reduces flow velocity in a flow passage formed in a piston base.SOLUTION: A reciprocating pump comprises a plurality of pumps 30. The plurality of pumps 30 each include: a piston 33 including a piston base 34 connected to a connecting rod 31, and including a flow passage 34e for fluid extending along a reciprocating direction, and a piston rod 35 provided in the piston base 34, and protruding to the side opposite to the connecting rod 31 along the reciprocating direction from the piston base 34; and a guide hole 36 for guiding the piston base 34 along the reciprocating direction, and housing the fluid passed through the flow passage 34e. In at least a pair of pumps 30 out of the plurality of pumps 30, the guide hole 36 of one pump 30 and the guide hole 36 of the other pump 30 are made to communicate with each other by a communication passage 60.SELECTED DRAWING: Figure 2

Description

The present invention relates to reciprocating pumps.

Patent Literature 1 discloses a reciprocating pump. This reciprocating pump has a crankcase to which liquid is supplied, a crankshaft and a connecting rod housed in the crankcase, and a piston connected to the connecting rod. The piston includes a crosshead (piston base) and a plunger (piston rod) provided in the crosshead. The crosshead is formed with a flow path for circulating the liquid in the crankcase to the plunger side.

JP 2016-217149 A

In the reciprocating pump described in Patent Literature 1, liquid is supplied to the plunger side through a channel formed at the base of the piston. In this configuration, the flow rate of the liquid supplied to the plunger side depends on the size of the channel and the flow velocity of the liquid flowing through the channel. In this case, if the flow velocity is increased in order to increase the flow rate, for example, cavitation may occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a reciprocating pump capable of suppressing the flow velocity in a flow path formed at the base of a piston.

An example of a reciprocating pump includes a crankcase (10) provided with a fluid inlet (11), and a crankshaft ( 20) and a plurality of pumps (30) connected to the crankshaft (20), each of the plurality of pumps (30) comprising a connecting rod (31) connected to the crankshaft (20) and a crank A piston (33) that reciprocates with the rotation of the shaft (20), the piston base (34) including a fluid flow path (34e) that is connected to the connecting rod (31) and extends along the reciprocating direction; and a piston (33) including a piston rod (35) provided at the piston base (34) and projecting from the piston base (34) along the reciprocating direction to the opposite side of the connecting rod (31); A guide hole (36) that guides the piston base (34) along and accommodates the fluid that has passed through the flow path (34e), and a pump that communicates with the guide hole (36) and accommodates the piston rod (35) A pump chamber (37) including a discharge valve (55) for discharging fluid, and a pump chamber (37) provided in the piston rod (35) for discharging the fluid contained in the guide hole (36). ), and in at least one pair of pumps (30) among the plurality of pumps (30), the guide hole (36) of one pump (30) and the guide hole (36) of the other pump (30). ) are communicated with each other by a communication passage (60).

In the above reciprocating pump, the fluid in the crankcase (10) sucked from the inlet (11) is discharged from the discharge valve (55) by the reciprocating motion of the piston (33) accompanying the rotational motion of the crankshaft (20). Dispensed. That is, when the piston (33) moves from the top dead center to the bottom dead center, the fluid in the crankcase (10) flows through the flow path (34e) of the piston base (34) and the valve body (39) of the piston rod (35). ) into the pump chamber (37). When the piston (33) moves from the bottom dead center to the top dead center, the fluid in the pump chamber (37) is discharged from the discharge valve (55). The reciprocating pump described above has a communication passage (60) that communicates between the two guide holes (6). Therefore, when the piston (33) moves from the top dead center to the bottom dead center in the one guide hole (36), the fluid flows from the crankcase (10) to the one guide hole (36) through the flow path (34e). Along with the inflow, the fluid can also flow into one guide hole (36) from the other guide holes (36) via the communication path (60). Further, when the piston (33) moves from the bottom dead center to the top dead center, the fluid in the guide hole (36) returns to the crankcase (10) through the flow path (34e) and flows through the communication path (60). The fluid can flow out to another guide hole (36) through. Since the fluid in the guide hole (36) circulates through the flow path (34e) and the communication path (60) in this manner, the flow velocity in the flow path (34e) formed at the base of the piston (34) is suppressed. be.

An example of the communication passage (60) may be located closer to the piston rod (35) than the piston root (34) in the reciprocating direction when the piston (33) is at the top dead center (P1). . With this configuration, the inlet/outlet (60a) of the communication passage (60) formed in the guide hole (36) is not covered with the piston base (34), and the one guide hole (36) and the other guide hole (36) are not covered with the piston base (34). ) are always in communication with each other.

In one example, the plurality of pumps (30) is three or more pumps (30), and the guide holes (36) of each of the plurality of pumps (30) are aligned with all other guides of the plurality of pumps (30). Each of the holes (36) may be in communication with each other through a communication passage (60). In this configuration, one guide hole (36) communicates with at least two or more other guide holes (36) through the communication paths (60).

In one example, the plurality of pumps (30) are three pumps (30), and when viewed from the reciprocating direction, the shape connecting the centers of the guide holes (36) of the three pumps (30) may be triangular. In this configuration, the guide holes (36) of the three pumps (30) can be communicated with each other by providing the communicating paths (60) along the sides of the triangle, for example.

ADVANTAGE OF THE INVENTION According to this invention, the reciprocating pump which can suppress the flow velocity in the flow path formed in the base of a piston can be provided.

It is a figure which shows the external appearance of an example reciprocating pump. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1; FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2; FIG. 2 is a cross-sectional view taken along line IV-IV of FIG. 1; It is a schematic diagram for demonstrating the relationship between a communicating path and a top dead center.

An example of the present invention will be described below with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is a diagram showing the appearance of an example reciprocating pump. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 3 is a cross-sectional view of the reciprocating pump taken along line III-III of FIG. 2 and showing a plane orthogonal to FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 1, showing a cross-sectional view of the reciprocating pump showing a plane perpendicular to the piston axis. As shown, the reciprocating pump 1 includes a crankcase 10, a crankshaft 20, and a plurality of pumps 30.

The crankcase 10 is hollow. This hollow portion serves as a channel through which the liquid to be used flows, and contains the liquid. A side surface of the crankcase 10 is provided with a liquid inlet 11 . The crankcase 10 is formed with an opening 12 which is closed by a bolted lid 13 . The crankcase 10 is provided with a connecting member 15 for connecting with a drive source such as an electric motor. The connection member 15 includes a tubular body 17 that communicates with the inside of the crankcase 10 and a flange 18 that extends radially outward from the tubular body 17 . For example, the drive source may be supported by flange 18 .

The crankshaft 20 is arranged inside the crankcase 10 . The crankshaft 20 is rotatably supported by a pair of bearings 19a and 19b provided in the crankcase 10. As shown in FIG. The pair of bearings 19a and 19b are provided on a pair of walls 10a and 10b that constitute the crankcase 10 and face each other. One bearing 19b is arranged in parallel with a connecting member 15 connected to a drive source. The crankshaft 20 supported by the bearings 19a and 19b is rotatable by the power of the drive source.

A plurality of pumps 30 are connected to the crankshaft 20 . For example, the plurality of pumps 30 may be three or more pumps. In the illustrated example, the plurality of pumps 30 are three pumps having similar configurations. The pump 30 includes a connecting rod 31 , a piston 33 , a guide hole 36 , a pump chamber 37 and a valve body 39 .

The connecting rod 31 is connected to the crankshaft 20 . As shown in FIGS. 1 and 2, an example connecting rod 31 has a large-diameter portion 31a on the rear side (on the side of the crankshaft 20) rotatable on the crankpin of the crankshaft 20 via a cylindrical bearing 31b. Concatenated. The connecting rod 31 is provided with a small diameter portion 31c on the side opposite to the large diameter portion 31a. The small diameter portion 31 c has a cylindrical shape with an axis parallel to the crankshaft 20 . In the reciprocating pump 1 as an example, the respective connecting rods 31 are connected to the crankshaft 20 so that the operation timings of the three pumps 30 are shifted from each other (for example, the phases are shifted from each other by 120°).

An example piston 33 includes a piston base 34 and a piston rod 35 . The piston base 34 has a substantially cylindrical shape. A concave portion 34a is formed on the side of the connecting rod 31 in the reciprocating direction of the piston base 34. The concave portion 34a is concave on the side opposite to the connecting rod 31. A piston pin 34b extending in a direction orthogonal to the reciprocating direction is formed in the recess 34a. The piston pin 34b is rotatably connected to the small diameter portion 31c of the connecting rod 31 via a cylindrical bearing 34c. 34 d of through-holes which penetrate the piston base 34 along the reciprocating direction are formed in the bottom face of the recessed part 34a. As a result, a fluid flow path 34e extending in the reciprocating direction is formed inside the piston base 34 in the radial direction by the concave portion and the through hole.

The guide hole 36 can guide the piston base 34 along the reciprocating direction and accommodate the fluid that has passed through the flow path 34 e of the piston base 34 . In one example, the guide hole 36 is configured by a columnar space forming part of the hollow portion of the crankcase 10 . The axial direction of the cylindrical space coincides with the reciprocating direction of the piston 33 . A cylindrical guide member 36a is arranged on the inner peripheral surface of the columnar space. In addition, since the reciprocating pump 1 of one example is of a multi-connected type including three pumps 30, the hollow portion of the crankcase 10 consists of a space in which the crankshaft 20 is arranged and three circles connected to the space. and a columnar space (guide hole 36).

The piston rod 35 is provided at the piston base 34 and projects from the piston base 34 along the reciprocating direction to the side opposite to the connecting rod 31 . In one example, the diameter of piston rod 35 is smaller than the diameter of piston base 34 . Also, the central axis of the piston base 34 and the central axis of the piston rod 35 are aligned.

A valve body 39 is provided on the piston rod 35 . The valve body 39 circulates the fluid contained in the guide hole 36 to the pump chamber 37 . In the illustrated example, a valve body 39 is included in the water intake valve mechanism 40 provided on the piston rod 35 . An example of the water intake valve mechanism 40 includes a valve body 39, a valve seat (sleeve) 41 on which the valve body 39 is seated/released, a collar 43, a fastener (nut) 45, etc., which are cylindrically configured and compressed. It is fitted over the piston rod 35 together with the spring 46 .

The valve seat 41 has a cylindrical shape. The valve seat 41 is provided with a plurality of through holes 41a along the axial direction. The plurality of through holes 41a are spaced apart from each other along the circumferential direction. The through hole 41 a functions as a flow path for flowing the working fluid from inside the crankcase 10 to the pump chamber 37 . A collar 43 is arranged downstream of the valve seat 41 . A valve body 39 is fitted on the upstream end of the collar 43 .

A fastener 45 is arranged downstream of the collar 43 , and a compression spring 46 is arranged between the fastener 45 and the valve body 39 so as to surround the collar 43 . In the water intake valve mechanism 40, the valve element 39 is seated on the valve seat 41 by the action of the compression spring 46, thereby closing the through hole 41a and closing the water intake valve. Further, the pressure of the fluid flowing into the through hole 41a from the guide hole causes the valve element 39 to separate from the valve seat 41, thereby opening the through hole 41a and opening the water intake valve.

The pump chamber 37 is a space communicating with the guide hole 36 and can accommodate the piston rod 35 and the water intake valve mechanism 40 . An example of the pump chamber 37 is formed by the inner space of a cylindrical connection pipe 51 connected to the crankcase 10 . The central axis of the connecting pipe 51 and the central axis of the guide member 36a are aligned. That is, the piston rod 35 reciprocates in the pump chamber 37 along the axial direction.

Pump chamber 37 includes a discharge valve 55 for discharging fluid. In one example, a connection pipe 51 forming a pump chamber 37 is connected to a manifold 53 , and a discharge valve 55 is arranged at a connection portion between the pump chamber 37 and the manifold 53 . The discharge valve 55 opens and closes the flow path by pressurization/decompression of the pump chamber 37 by the pumping action of the water intake valve mechanism 40 , and discharges the pressurized working liquid in the pump chamber 37 to the outside of the pump chamber 37 when the discharge valve 55 is opened.

In the reciprocating pump 1 having the above configuration, the fluid sucked into the crankcase 10 through the inlet 11 is discharged from the discharge valve 55 by the reciprocating motion of the piston 33 accompanying the rotation of the crankshaft 20 . That is, when the piston 33 moves from the top dead center to the bottom dead center, the fluid in the crankcase 10 reaches the guide hole 36 through the flow path 34 e of the piston base 34 . The fluid that has reached the guide hole 36 flows into the pump chamber 37 through the water intake valve mechanism 40 of the piston rod 35 . The fluid in the pump chamber 37 is discharged from the discharge valve 55 when the piston 33 moves from the bottom dead center to the top dead center.

In such a reciprocating pump 1, the flow rate of the liquid supplied into the guide hole 36 can depend on the size of the channel 34e and the flow rate of the liquid flowing through the channel 34e. In this case, if the flow velocity is increased in order to increase the flow rate, cavitation may occur, for example. In order to increase the flow rate, for example, it is conceivable to increase the cross-sectional area of the flow path 34e.

Therefore, the reciprocating pump 1 of one example has a communication passage 60 as shown in FIG. The communication path 60 is a flow path that communicates the guide holes 36 of the plurality of pumps 30 with each other, and is formed in the crankcase 10 . The communication path 60 may be, for example, a linear flow path having a circular cross section. The guide hole 36 of each pump 30 communicates with the guide holes 36 of all the other pumps 30 through the communicating passages 60 . Since the reciprocating pump 1 of this example has three pumps 30 , the guide holes 36 of the three pumps 30 are connected to each other by three communication paths 60 . As shown in FIG. 4, when viewed in the reciprocating direction, the shape connecting the centers of the guide holes 36 of the three pumps 30 is triangular. The three communicating paths 60 are arranged along the sides of the triangle.

FIG. 5 is a schematic diagram for explaining the relationship between the communicating path and the top dead center. In FIG. 5, the guide hole 36, the communicating path 60 formed in the guide hole 36, and the reciprocating piston base 34 are schematically depicted. As shown in FIG. 5, in the reciprocating pump 1 of the example, when the piston base 34 is at the top dead center P1, the communication path 60 is closer to the piston rod 35 than the piston base 34 (bottom dead center) in the reciprocating direction. point side). That is, the inlet/outlet (opening) 60a of the communicating passage 60 is not completely covered with the piston base 34 when the piston 33 is at the top dead center P1, and at least a portion thereof is always exposed. In the illustrated positional relationship, when the piston 33 is at the top dead center P1, about half of the entrance/exit 60a of the communication passage 60 is exposed. The entrance/exit 60a of the communication passage 60 may be completely exposed when the piston 33 is at the top dead center P1.

According to such a reciprocating pump 1, when the piston 33 moves from the top dead center to the bottom dead center in the one guide hole 36, the fluid flows from the crankcase 10 into the one guide hole 36 through the flow path 34e. At the same time, fluid can also flow into one guide hole 36 from other guide holes 36 via the communication passage 60 . Further, when the piston 33 moves from the bottom dead center to the top dead center, the fluid in the guide hole 36 returns to the crankcase 10 via the flow path 34e and flows to the other guide hole 36 via the communication path 60. can flow out. As described above, the fluid in the guide hole 36 flows not only through the passage 34e but also through the communication passage 60, so that the flow velocity in the passage 34e formed in the piston base 34 is suppressed. Also, the flow rate can be increased without enlarging the piston 33 .

An example of the communication passage 60 is positioned closer to the piston rod 35 than the piston base 34 in the reciprocating direction when the piston 33 is at the top dead center. In this configuration, the entrance/exit 60a of the communication passage 60 formed in the guide hole 36 is not covered with the piston base 34, and the one guide hole 36 and the other guide hole 36 are always communicated. Therefore, when the piston 33 moves from the top dead center to the bottom dead center, the fluid is allowed to flow into the guide hole 36 via the communication passage 60 from the beginning of the operation. Further, when the piston 33 moves from the bottom dead center to the top dead center, fluid is allowed to flow out through the communication passage 60 until the end of the operation.

In one example, the plurality of pumps 30 is three or more pumps 30 , and the guide holes 36 of each of the plurality of pumps 30 communicate with each of all the other guide holes 36 of the plurality of pumps 30 via the communication passages 60 . are communicated. In this configuration, one guide hole 36 communicates with at least two or more other guide holes 36 through the communication paths 60, respectively.

In one example, the plurality of pumps 30 are three pumps 30, and when viewed from the reciprocating direction, the shape connecting the centers of the guide holes 36 of the three pumps 30 is triangular. . In this configuration, the guide holes 36 of the three pumps 30 can be communicated with each other by providing the communicating paths 60 along the sides of the triangle, for example. In this case, it is easy to make the lengths of the three communicating paths 60 the same.

Although exemplary embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. For example, although an example in which three pumps are connected to each other by the communication passage 60 has been shown, in at least one pair of pumps among the plurality of pumps, the guide hole of one pump and the guide hole of the other pump are connected. It is sufficient if they are communicated with each other by passages.

Further, although an example in which the guide holes 36 are connected to each other by the communicating path 60 having a circular cross section has been shown, the aspect of the communicating path 60 is not limited to this. The shape of the communication path 60 is not particularly limited as long as the guide holes 36 are communicated with each other. For example, when the shape connecting the centers of the guide holes of the three pumps is triangular, the guide holes may be communicated with each other by the planar communication space forming the triangular shape.

DESCRIPTION OF SYMBOLS 1... Reciprocating pump 10... Crankcase 20... Crankshaft 30... Pump 31... Connecting rod 33... Piston 34... Piston base 35... Piston rod 34e... Flow path 36... Guide hole 37... Pump chamber 39...Valve body 55...Discharge valve 60...Communication path.

Claims (4)

a crankcase (10) provided with a fluid inlet (11);
a crankshaft (20) arranged in the crankcase (10) and rotatably supported by the crankcase (10);
a plurality of pumps (30) connected to the crankshaft (20);
each of the plurality of pumps (30) comprising:
a connecting rod (31) connected to the crankshaft (20);
A piston (33) that reciprocates with the rotation of the crankshaft (20), the piston base including the fluid flow path (34e) that is connected to the connecting rod (31) and extends along the reciprocating direction. (34), and a piston rod (35) provided at the piston base (34) and protruding from the piston base (34) along the reciprocating direction in the direction opposite to the connecting rod (31). a piston (33);
a guide hole (36) that guides the piston base (34) along the reciprocating direction and accommodates the fluid that has passed through the flow path (34e);
a pump chamber (37) communicating with the guide hole (36) and accommodating the piston rod (35), the pump chamber (37) including a discharge valve (55) for discharging the fluid;
a valve body (39) provided in the piston rod (35) for circulating the fluid contained in the guide hole (36) to the pump chamber (37);
In at least one pair of pumps (30) among the plurality of pumps (30), the guide hole (36) of one pump (30) and the guide hole (36) of the other pump (30) are connected. reciprocating pumps which are in communication with each other by means of passages (60); The communication passage (60) is located closer to the piston rod (35) than the piston base (34) in the reciprocating direction when the piston (33) is at the top dead center (P1). 2. A reciprocating pump according to claim 1, wherein: the plurality of pumps (30) is three or more pumps (30);
The guide hole (36) of each of the plurality of pumps (30) communicates with each of the other guide holes (36) of the plurality of pumps (30) by the communication passage (60). 3. A reciprocating pump according to claim 1 or 2, wherein the plurality of pumps (30) is three pumps (30);
4. A reciprocating movement according to claim 3, wherein a shape connecting the centers of said guide holes (36) of said three pumps (30) is triangular when viewed from said reciprocating direction. pump.

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