JP2652375B2 - Piston pump suction valve mechanism - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suction valve mechanism of a piston pump, and more particularly, to a suction valve member fixed to a distal end portion of a piston body and a cylindrical member adapted to reciprocate the piston body. The present invention relates to a suction valve mechanism that moves relative to a piston body between a suction valve member and a stop member.

[Conventional technology]

In a forced valve type piston pump, a suction valve member, a collar member, and a stop member are fitted to a distal end portion of a piston body in order from a base end portion, and a cylindrical member is disposed outside the collar member. The cylindrical member has a through hole for liquid passage in the axial direction, and is relatively movable with respect to the piston body in a range between the suction valve member and the stop member in the axial direction. The pump chamber defines the suction valve member side, and the cylindrical member slides on the inner periphery of the seal member. In the stroke in which the piston body moves toward the distal end, the cylindrical member contacts the suction valve member, the communication between the pump chamber and the suction port is cut off, the discharge valve means opens, and the liquid in the pump chamber is opened. During the stroke in which the piston is moved toward the base end by the discharge valve means, and the cylindrical member contacts the stop member and separates from the suction valve member, the discharge valve means closes, and the liquid at the suction port is closed. Is introduced into the pump chamber through a gap between the end surface of the cylindrical member and the suction valve member and a through hole in the cylindrical member.

In the conventional suction valve mechanism of such a piston pump,
The cylindrical member is loosely fitted on the outer side of the collar member, and only slides on the outer peripheral edge of the seal member on the outer periphery.
A member for supporting and guiding the cylindrical member with respect to the axial movement has not been particularly provided.

[Problems to be solved by the invention]

Therefore, the movement of the cylindrical member in the axial direction becomes unstable, and the seal member wears unevenly, thereby reducing the durability of the seal member.

An object of the present invention is to provide a suction valve mechanism of a piston pump that can improve the durability of a seal member that maintains the liquid tightness of a pump chamber against sliding of a cylindrical member.

[Means for solving the problem]

ADVANTAGE OF THE INVENTION According to the suction valve mechanism of the piston pump of this invention, the cylindrical member which reciprocates via a collar member at the outer periphery of the small diameter part of the reciprocating piston body connected with the drive part, and the suction valve which contacts this cylindrical member In a piston pump fitted with a member, a cylinder that fixes and holds a valve seat member of the discharge valve means is sandwiched between a cylinder base that covers the piston body and a cylinder tip that houses the discharge valve means, A seal member that defines and defines a side edge of the pump chamber is sandwiched and held at opposite ends of the cylinder base and the cylinder, and a collar member that is fixed by contacting a stop member that is fitted to the piston body, A sliding surface having a non-circular cross section in the axial direction is formed between the facing edge of the cylindrical member fitted to the outer edge of the collar member, and the cylindrical member is slidably supported by the inner edge of the seal member and the outer edge of the collar member.

[Action]

With the reciprocation of the piston body, the cylindrical member moves relative to the piston body between the suction valve member and the stop member in the axial direction of the piston body. In the relative movement of the cylindrical member, since the inner periphery of the cylindrical member slides on the outer periphery of the collar member, the cylindrical member moves relative to the piston body while being guided by the collar member. The sliding position in the radial direction between the outer periphery of the cylindrical member and the inner periphery of the seal member is fixed.

〔Example〕

 Hereinafter, the present invention will be described with reference to embodiments of the drawings.

FIG. 1 is an overall structural view of a piston pump having a suction valve mechanism according to the present invention. The piston pump 10 shown in FIG. 1 is used, for example, for pumping agricultural chemicals to a predetermined nozzle or the like. In this piston pump 10, a crankshaft 12 is disposed in a crankcase 14, and crankcases are provided at both ends. The connecting rod 16 is rotatably supported on the crankshaft 12 at one end thereof. Cylinder source 18, cylinder 20, and cylinder destination 22
The crankcase 14 is arranged in that order, and is fastened to the crankcase 14 by predetermined fastening means.

The piston body 24 has a large diameter portion 26 on the proximal end side and a small diameter portion on the distal end side.
28, extends horizontally in the crankcase 14, the cylinder base 18, and the cylinder 20, and is rotatably coupled to the other end of the connecting rod 16 at the base end of the large diameter portion 26. The crankshaft 12 serves as a drive unit for the piston body 24. The oil seal 30 is a piston body in the crankcase 14.
The piston 24 is disposed at a penetrating portion and prevents oil in the crankcase 14 from leaking out of the crankcase 14 due to sliding of the piston body 24. The seal packing 32 is disposed on the inner periphery of the end of the cylinder base 18 on the side of the crankcase 14, and the inner peripheral edge is brought into sliding contact with the peripheral surface of the large diameter portion 26 of the piston body 24.

A suction valve member 34, a collar member 36, and a stop member 38 are fitted and disposed on the small-diameter portion 28 in order from the base end side, and a nut 40 is screwed to a distal end portion of the small-diameter portion 28 to be engaged with these suction valve members. 34, the collar member 36 and the stop member 38 are tightened and fixed to the large diameter portion 26.
The stop member 38 is provided with a plurality of through holes 42 penetrating both sides thereof. The cylindrical member 44 is a collar member on the inner circumference.
A plurality of through holes 46 are fitted at equal angular intervals so as to slide on the outer periphery of the collar member 36 and to penetrate in the axial direction. Seal packing 48 as seal member
Is fitted in an annular groove formed between the cylinder base 18 and the cylinder 20, and the outer periphery of the cylindrical member 44 is slid on the inner peripheral edge.

The discharge valve 50 includes a valve seat member 52 and a sack 54 whose peripheral edges are sandwiched between the end surface of the cylinder 20 and the step of the cylinder tip 22. The valve body 56 is disposed in the sack 54 so as to be able to be seated on the valve seat member 52, and is compressed by a compression coil spring 58.
Pressed to. The through hole 60 is formed in the side wall of the sack 54 and communicates the inside and the outside of the sack 54. The O-rings 62 and 64 are fitted into annular grooves at both ends of the cylinder 20 to maintain the liquid-tightness of the joint between the cylinder 20 and the cylinder base 18 and the cylinder tip 22, and the O-ring 66 is a valve seat member. 52 is fitted into an annular groove on the outer peripheral portion, and maintains liquid tightness at that location.

The suction port 68 is defined in the cylinder base 18, the pump chamber 70 is defined between the seal packing 48 and the valve seat member 52, and the discharge port 72 is defined in the cylinder tip 22.

In the stroke in which the piston body 24 moves toward the discharge valve 50, the end face of the cylindrical member 44 abuts on the suction valve member 34, and the pump chamber 70
The communication between the pump chamber 70 and the suction port 68 is cut off, and the liquid in the pump chamber 70 is pumped toward the discharge valve 50. In the discharge valve 50, the valve body 56 is separated from the valve seat member 52 against the compression coil spring 58 by the liquid pressure-fed from the pump chamber 70. As a result, the liquid in the pump chamber 70 is discharged to the discharge port 72 through the valve seat member 52 and the through hole 60, and is pumped from the discharge port 72 to a nozzle or the like.

In the stroke in which the piston body 24 moves toward the base end, the discharge valve 50 is closed due to a decrease in the pressure in the pump chamber 70, and the cylindrical member 44 contacts the stop member 38 so that the suction valve member 34
From the end surface of the cylindrical member 44 and a suction valve member 34. The liquid in the suction port 68 further flows through the gap between the end face of the cylindrical member 44 and the suction valve member 34 to form a through hole 46 in the cylindrical member 44.
And enters the pump chamber 70 through the through hole 42 of the stop member 38.

As the piston body 24 reciprocates, the cylindrical member 44 moves relative to the piston body 24 between the suction valve member 34 and the stop member 38 in the axial direction of the piston body 24. In the relative movement of the cylindrical member 44, the inner periphery of the cylindrical member 44 is
The cylindrical member 44 is stably moved relative to the piston body 24 without being displaced in the radial direction of the piston body 24 because the cylindrical member 44 is slid relatively to the piston body 24 while being supported by the outer periphery of the piston body 24.

2 (a) to 2 (e) show various examples of the through hole 74 of the cylindrical member 44. FIG. The circumferential contour of the cross section of the collar member 36 fitted to the small diameter portion 28 of the piston body 24 matches the circumferential contour of the through hole 74 in FIGS. 2 (a) to 2 (e). Second
The peripheral contour of the through hole 74 in FIGS. 7A to 7E is non-circular, that is, since the sliding surface between the collar member 36 and the cylindrical member 44 is non-circular, the cylindrical member 44 and the collar Relative rotation with the member 36 is prevented. As a result, even if the cylindrical member 44 is disassembled from the piston body 24 for inspection or the like, the cylindrical member 44 can be assembled to the piston body 24 via the collar member 36 at the same relative rotational position as before disassembly, and the suction valve Element
The contact surface between the cylindrical member 44 and the cylindrical member 44 can be made the same as before the disassembly after the assembling, so that the liquid tightness after the assembling can be improved. In FIG. 2 (a), the peripheral surface of the through hole 74a is composed of a plurality of triangular grooves continuous in the circumferential direction. Second
In FIG. 8B, the peripheral surface of the through hole 74b is substantially circular as a whole, but a pair of grooves is formed at a position 180 ° apart in the circumferential direction. In FIG. 2C, the through hole 74c is formed in a square cross section. In FIG. 2 (d), the peripheral surface of the through hole 74d is substantially circular as a whole, but grooves are formed at 90 ° intervals in the circumferential direction. In FIG. 2 (e), the through hole 74e
Is composed of a circular arc and a straight line, and the assembling position is limited to one location, so that the assembling position is surely the same as before disassembly.

3 (a) to 3 (d) show various fixing modes of the seal packing 48. FIG. The seal packing 48 is mounted in an annular groove formed at a joint between the cylinder base 18 and the cylinder 20 when the cylinder base 18 and the cylinder 20 are assembled.
The necessity of preparing a special additional member for fixing the seal packing 48 can be omitted. In cylinder 20a, end 78
a and 80a are both reduced in outside diameter,
The seal packing 48 is fitted in the annular groove between the end of the end 80a and the step of the cylinder base 18. In the cylinder 20b, the ends 78b and 80b are formed so that the outer circumference is straight or stepped, and the cylinder ends are respectively.
22 and the inner circumference of the cylinder base 18
Is fitted to the inner peripheral step of the end portion 80b, and as a result,
When the cylinder 20b is pulled out, the tightening of the seal packing 48 is loosened, and replacement of the seal packing 48 becomes easy. In the cylinder 20c, the end portion 78c has a reduced outer diameter, the end portion 80c has a step formed on the inner periphery thereof, and is fitted to the inner periphery of the cylinder tip 22 and the inner periphery of the cylinder base 18, respectively. The seal packing 48 is fitted between the inner peripheral step portion and the end face of the cylinder base 18 and the washer 81 is inserted into the cylinder tip 18 side of the seal packing 48 while the seal packing 48 is fitted to the cylinder 20c. Can adjust the interference. Cylinder 20
In (d), the end portion 78d is reduced in outer diameter, the end portion 80d is set to have the same inner and outer diameters as the middle portion of the cylinder 20d, and the end surface is applied to the end surface of the cylinder base 18, and the seal packing 48 is attached to the end portion 80d. It is fitted in an annular groove between the end face and the step on the inner periphery of the cylinder base 18.

4 (a) to 4 (d) show various stop members 38. FIG. The stop member 38 in FIG. 1 has substantially the same outer diameter as the outer diameter of the cylindrical member 44, and a through hole 42 is formed in the stop member 38. On the other hand, FIGS. d) Stop member 38a-3
8d, the outer peripheral edges of the stop members 38a to 38d have the through holes 46 of the cylindrical member 44 when assembled to the small diameter portion 28 of the piston body 24.
The outer diameter is defined so as to fit inside the semi-outer diameter direction from a. Therefore, the formation of the through hole 42 in the stop members 38a to 38d can be omitted, and the flow of the liquid from the through hole 46 of the cylindrical member 44 to the pump chamber 70 can be made smooth. Stop members 38a to 38d are small diameter portions of piston body 24 at the center.
It has a through hole 82 that penetrates through. The outer peripheral contour of the stop member 38a is circular, the outer peripheral contour of the stop member 38b is square, the outer peripheral contour of the stop member 38c is substantially triangular, and the outer peripheral contour of the stop member 38d is substantially cross-shaped.

FIGS. 5 (a) to 5 (c) show the cylindrical member 44 as a suction valve member.
Various examples of the piston pump 10 provided with a compression coil spring 88 biasing toward 34 are shown. The compression coil spring 88 ensures that the cylindrical member 44 closely adheres to the suction valve member 34 during the discharge stroke, and that the cylindrical member 44 quickly adheres to the suction valve member 34 when switching from the suction stroke to the discharge stroke.
The efficiency of the pump can be improved. In FIG. 5 (a), the spring support 90 has a small diameter portion on the side of the compression coil spring 88 of the cylindrical member 44.
The compression coil spring 88 is fitted between the stop member 38 and the spring receiver 90 so as to be fitted in the suction valve member 34 and the collar member 36. In FIG. 5B, the stop member 38a is a compression coil spring 8
The compression coil spring 88 is also provided between the stop member 38a and the inside of the end surface of the cylindrical member 44, and also serves as a spring receiver of 8, thereby reducing the number of components. In FIG. 5C, the compression coil spring 88 is contracted between the stop member 38a and the spring receiver 90 (the same part as the stop member 38a), and the stop member and the spring receiver can be covered by the same part.

〔The invention's effect〕

Thus, according to the present invention, the cylindrical member slides along the non-circular sliding surface between the cylindrical member and the outer peripheral surface of the collar member. The movement is stable without being deviated in the radial direction, whereby the sliding portion between the outer peripheral surface of the cylindrical member and the seal member is constant, and the force acting on the seal member is constant, so that the durability is improved. Further, since the contact surface between the cylindrical member and the suction valve member is constant, high watertightness is maintained.

[Brief description of the drawings]

The drawings relate to an embodiment of the present invention. FIG. 1 is an overall structural view of a piston pump having a suction valve mechanism according to the present invention, and FIGS. 2 (a) to 2 (e) show various types of through holes in a cylindrical member. FIGS. 3 (a) to 3 (d) show various fixing modes of the seal packing, FIGS. 3 (a) to 4 (d) show various stopper members, and FIGS. (A) thru | or (c) are figures which show the various examples of the piston pump provided with the compression coil spring which urges a cylindrical member toward a suction valve member. 10 ... Piston pump, 12 ... Crank shaft (drive part), 18 ... Cylinder base, 20 ... Cylinder, 22 ... Cylinder tip, 24,24a, 24b ... Piston body, 28 ... Small diameter part, 34
…… Suction valve member, 36 …… Collar member, 38, 38a …… Stop member, 44 …… Cylinder member, 48 …… Seal packing (seal member), 50 …… Discharge valve, 52 …… Valve seat member, 70 ……pump room.

Claims (3)

(57) [Claims] 1. A piston fitted with a cylindrical member reciprocating via a collar member at the outer edge of a small diameter portion of a reciprocating piston body connected to a driving portion, and a suction valve member abutting on the cylindrical member. In the pump, a cylinder that fixes and holds a valve seat member of the discharge valve means is interposed between a cylinder base that covers the piston body and a cylinder tip that houses the discharge valve means. A seal member that defines a side edge of the pump chamber is sandwiched and held at opposing ends of the collar member, and a collar member that is fixed in contact with a stop member that is fitted to the piston body; A sliding surface having a non-circular cross section in the axial direction is formed between opposed edges of a cylindrical member fitted to the piston member, and the cylindrical member is slidably supported by an inner edge of the seal member and an outer edge of the collar member. Suction Mechanism. 2. A suction valve mechanism for a piston pump according to claim 1, wherein one or more of said seal members are provided. 3. The suction valve mechanism for a piston pump according to claim 1, wherein an inner diameter of said seal member is formed within an axial diameter of said cylindrical member.