JP2706688B2 - Reciprocating motion switching device for pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a reciprocating switching device used for a reciprocating pump. (Prior Art) Conventionally, as shown in Japanese Utility Model Publication No. 49-40805, a piston is slidably fitted inside a cylinder body,
The piston is movably provided with two types of valves for controlling a working fluid pressure applied to one side of the piston and a working fluid pressure applied to the other side, and a central portion of the piston is associated with reciprocation of the piston. There is a reciprocating switching device for a pump provided with a valve operating body that operates two types of valves by a snap action by a spring. In this conventional device, a compression coil spring is used as the spring, so a spring mounting shaft for fitting the spring, a structure in which the shaft is rotatably mounted on a valve operating body in a central portion, A spring receiving member or the like that is slidably fitted to the spring mounting shaft and rotatably fitted to a member integral with the piston is required. For this reason, assembling these parts is not easy, it is troublesome, and the number of parts is large, so there is a limit to cost reduction. On the other hand, Japanese Patent Application Laid-Open No. Sho 60-256571 discloses a reciprocation switching device in which a pair of spool valve springs is provided for a spool valve body for switching reciprocation of a piston. This spool valve spring is a meandering wire spring (FIG. 6), and the outer end of the meandering spring is fixed to the inside of the pump housing by a screw (page 7, upper right column on page 7). Lines 8 to 11),
The loops inside the meandering spring are engaged in the grooves of the spool valve body (page 7, upper right column, lines 13 to 16). (Problems to be Solved by the Invention) The meandering spring described in the above-mentioned Japanese Patent Application Laid-Open No. Sho 60-256571 has its ends fixed by screws and free rotation of the ends is restricted. Since the spring wire is twisted and twisting does not provide a sufficient reversing stroke, it must be formed in a meandering shape to secure a sufficient distance between the ends and the loop for the reversing operation. A sufficient spring mounting space is required, and metal fatigue of the spring wire due to torsion cannot be ignored. In addition, the meandering spring acts on the loop during compression because the inner loop is engaged with the groove of the spool valve body and the tip of the loop is open so that it can move freely in the axial direction. Forces may escape in the axial direction. Further, the end of the meandering spring needs to be fixed to the pump housing with a screw. Even after fixing, the loosening of the screw may cause the meandering spring to fall off and impair its function. Care must be taken when attaching. The present invention has been made in view of such a point,
A spring shape that can reduce the number of parts, assemble easily, and reduce costs, achieve a large reversing stroke even with a small size, has excellent durability with little metal fatigue of wires, and can effectively accumulate compressive force. It is another object of the present invention to provide a reciprocating switching device for a pump having the mounting structure. (Means for Solving the Problems) According to the present invention, a cylinder head is provided at one end of a cylinder body, and a single rod-shaped piston is slidably fitted inside the cylinder body. A valve seat mounting portion is integrally provided at the end on the side of the cylinder, and supplies one working air chamber located on the rod side of the piston in the cylinder body and an air chamber located on the cylinder head side of the valve seat mounting portion. Communication with the mood,
One of the valve seats is provided on a surface of the valve seat mounting portion facing the piston, and one of the valve seats is communicated with the outside. The other valve seat is communicated with the other working air chamber formed between the valve seat mounting portion and the piston, and one valve is provided on one valve seat so as to be able to freely contact and separate. The other of the valves is provided integrally with the other valve seat that is freely movable toward and away from the other valve seat by a shaft portion that penetrates the valve seat mounting portion, and one of the valves is axially movable to the central portion of the valve seat mounting portion. The valve actuating body arranged at the position is movably fitted within a certain range in the axial direction, and both ends of the valve actuating body are engaged. A spring is provided to move the piston to the one side and the other side in the axial direction by a snap action, and a switching rod that slides the movement of the terminal end of the movement of the piston toward the rod side to the valve operating body slides inside the valve operating body. A reciprocating switching device for a pump, which is freely fitted and provided with an engagement portion that transmits a movement of a movement end portion in movement of the piston toward the cylinder head to a valve operating body at a central portion of the piston, As the spring, a substantially C-shaped wire spring is formed by bending both ends in directions opposite to each other with respect to a rear portion located at the center of the wire, and the rear portion of the wire spring is connected to the valve seat mounting portion. The wire spring is rotatably fitted to a spring fitting portion provided integrally with the valve spring. The set has been transverse bore a reciprocating switching device for rotatably fitted to a pump. (Operation) In the present invention, the valve operating body is relatively moved in relation to the movement of the piston, and after the valve operating body starts moving, the neutral point at which the wire spring is perpendicular to the piston axial direction. Until then, the C-shaped wire spring bends due to the compressive force in the direction of pressing the notch of the spring to the opposite side, and after the neutral point, the restoring force of the wire spring causes the valve operating body to The operation is instantaneously switched to the opposite stable state, and the state is maintained.
At the time of this switching operation, the C-shaped wire spring freely rotates about its back and both ends as a rotation center axis, and the C-shaped wire spring smoothly reverses and is located between the back and both ends. Only bending acts on the curved portion, and twisting does not act. Further, since the C-shaped wire spring has an endless spring formed by fitting opposite ends of the C-shaped wire spring into a lateral hole of the valve operating body, the C-shaped wire spring is fitted to the valve operating body with a spring. There is no escape for the compression force when compressed between the parts and the compression force is effectively stored in the C-shaped wire spring. Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. As shown in FIG. 1, a cylinder head 12 is screwed to the outside at the upper end of the cylinder body 11, and O
A ring 13 is fitted, and a valve seat mounting part 14 is
Are screwed together, and an O-ring 15 is fitted between them. A piston 21 is slidably fitted to the inside of the cylinder body 11 via an O-ring 22, and an engaging portion 23 is screwed to a central portion of the piston 21. A pair of valve seats 25 formed of rubber or the like are fitted on the upper surface of the valve seat mounting portion 14, and a shaft portion 28 of a valve 27 is inserted into an air supply hole 26 provided in the valve seat 25 and the valve seat mounting portion 14. Is loosely fitted. A disc-shaped valve 31 is arranged below the valve seat mounting portion 14, and the valve 31 is attached to the valve 27.
The screw portion 32 provided on the shaft portion 28 is screwed. A pair of valve seats 34 fitted to the lower surface of the valve seat mounting portion 14 face the disk-shaped valve 31. The valve seat 34 is formed of a rubber material in the same manner as the valve seat 25.
And the exhaust hole 35 provided in the valve seat mounting portion 14,
An exhaust passage 38 formed between the outer cylindrical portion 36 and the inner cylindrical portion 37 communicates with an exhaust port 39 to the outside atmosphere formed at the upper end of the cylinder head 12. 40 is two O-rings fitted concentrically. As shown in FIGS. 1 and 2, a spring fitting portion 41 is integrally formed below the valve seat mounting portion 14, and concave grooves 42 are formed on opposite side surfaces of the spring fitting portion 41. Is provided. A wire spring formed into a substantially C-shape with a wire having a round cross section is formed in the concave grooves 42 on both sides.
A back surface portion 44 located at the center of 43 is rotatably fitted. Both ends 45 facing each other via the notch in the wire spring 43 are slightly opened between the both ends 45, and are formed on both side surfaces of the engagement projection 47 at the lower end of the valve operating body 46. It is rotatably fitted in the horizontal hole by its own restoring force. The valve operating body 46 is a disc-shaped valve.
It is slidably fitted to the center of 31 and the upper end also has an engaging projection
48 are provided. A plunger 52 is screwed and integrated with the rod portion 51 of the piston 21, and the inner space 53 of the plunger 52 is slidable with the engaging portions 23 and the central holes 54 and 55 of the valve operating body 46. The switching rod 56 fitted to is inserted. At the upper end of the switching rod 56, an engaging portion 57 that moves up and down inside the inner cylindrical portion 37 and engages with the engaging convex portion 48 when descending is provided integrally, and the lower end is provided with the engaging portion 23. Nuts to engage 60
Is screwed. Inside the cylinder body 11, a working air chamber 58 located above the piston 21 and a working air chamber 59 located below the piston 21 are defined by the piston 21. A pump body 61 is screwed into a lower portion of the cylinder body 11, and an air supply passage 62 is formed in the pump body 61 so as to communicate with the working air chamber 59. 63 is screwed, and the air supply port 64 of this fitting 63 is
The cylinder head 12 communicates with the air supply passage 62 through an air supply hole 65, communicates with an air supply pipe 67 through an air supply hole 66 formed in the side surface, and further passes through the curved pipe 68 from the air supply pipe 67. The air chamber 69 is communicated with the inside. O-rings 71 and 72 are fitted on the inner peripheral surface of the pump body 61, and the pressure of the working air chamber 59 is maintained by the O-rings 71 and 72. As shown in FIG. 2, straight portions 82 at both ends of a stopper 81 formed in a semicircular shape are inserted from the inside into the screw portion 32 of the valve 27, and the screw portion 32 of the valve 27 rotates. Has been prevented. When the stopper 81 is removed at the time of disassembly, the straight portions 82 at both ends are moved to the center and removed from the screw portion 32 against the shape retaining characteristics. The plunger 52 functions as a plunger pump together with a non-illustrated check valve and the like. However, since the pump portion is a normal one, it is not particularly illustrated. Next, the operation of this embodiment will be described with reference to FIG. First, the pair of wire springs 43 is inverted upward,
The valve operating body 46 is pushed upward by the urging force, and the disc-shaped valve 31 is engaged by the engaging projection 47 of the valve operating body 46.
Will be described from the state where it is also pushed upward. The air as the working fluid pressurized and supplied from the air supply port 64 to the air chamber 69 via the air supply pipe 67 and the like is supplied to the open valve seat 25.
Then, the air enters the air chamber 58 on the upper side of the piston through the air supply hole 26.
At this time, the valve seat 34 on the exhaust side is
Is closed by Since air is also supplied under pressure from the air supply port 64 to the air chamber 59 below the piston via the passage 62, the air pressure acting on both side surfaces of the piston 21 is substantially equal, but the pressure receiving area above and below the piston is Depending on the presence or absence of the rod portion 51, the piston pressure receiving area facing the air chamber 58 is larger than the piston pressure receiving area facing the air chamber 59, so that the air pressure of the air chamber 58 The piston 21 moves downward in FIG. In this process, the plunger 52 performs a discharging operation. When approaching the limit of the discharge stroke, the engagement portion of the piston 21
23 contacts the nut 60 of the switching rod 56, the switching rod 56 is moved downward, and the locking portion 57 at the upper end thereof also moves the valve operating body 46 downward. At this time, wire spring
As for 43, both ends 45 are moved downward about the back 44.
At this stage, the rear part 44 and both ends 45 of the wire spring 43
When a compressive force acts between the two and the both ends 45 move slightly downward beyond the position shown in FIG. 1, the restoring force of the wire spring 43 causes the valve operating body 46 to move.
It is greatly moved downward instantaneously. As a result, the engaging projection 48 strongly hits the disc-shaped valve 31, and this valve 31 opens the exhaust valve seat 34 and the valve 27 closes the air supply valve seat 25. Therefore, the supply of air from the air chamber 69 to the air chamber 58 on the upper side of the piston is cut off, and the piston 21 moves upward by receiving the air pressure of only the lower air chamber 59. At this time, the air in the air chamber 58 on the upper side of the piston is
The air is discharged to the outside through the exhaust hole 35, the exhaust passage 38, and the exhaust port 39 sequentially. In the upward piston movement stroke, the plunger 52 performs a suction action. When the upward stroke of the piston 21 approaches the limit, the engaging portion 23 comes into contact with the valve operating body 46, and moves the operating body 46 upward. At this time, wire spring
Both ends 45 of 43 are also moved upward centering on the back 44. At this stage, when a compressive force acts between the back 44 and both ends 45 of the wire spring 43 and the ends 45 move slightly upward beyond the position shown in FIG. Due to the restoring force of 43, the valve operating body 46 is instantaneously largely moved upward. As a result, the lower engaging projection 47 of the valve operating body 46 strongly hits the disk-shaped valve 31, and the valve 31 closes the exhaust valve seat 34 and the air supply valve seat 25. It is opened and returns to the state where the explanation started. In the above embodiment, a pair of wire springs 43 is used, but the wire spring may be provided on only one side. (Effects of the Invention) According to the present invention, a substantially C-shaped wire spring is formed by bending both ends in directions opposite to each other with respect to a rear portion located at the center of the wire, and the rear portion of the wire spring is formed. Is rotatably fitted to the spring fitting portion of the valve seat mounting portion, and furthermore, both ends of the wire spring are rotatably fitted to the lateral holes of the valve operating body. Of the C-shaped wire spring is slightly opened, and is fitted to the lateral hole by its own restoring force. It has an advantage that it can be easily mounted and does not come off after being mounted, and the number of components is small, so that a significant cost reduction can be achieved as compared with the conventional product. Further, according to the present invention, the rear portion and both ends of the C-shaped wire spring are freely rotated as the rotation center axis, and the wire spring smoothly reverses, and the gap between the rear portion and both ends. Since only the bending acts on the curved portion in the above, no torsion acts, a large reversing stroke can be obtained even with a small wire spring that does not require much mounting space, and the wire has little metal fatigue and has excellent durability There is also an effect. In addition, according to the present invention, the C-shaped wire spring has an endless spring formed by fitting opposite ends of the C-shaped wire spring into a lateral hole of the valve operating body. When compressed between the valve operating body and the spring fitting portion, there is no escape of the compression force, and the compression force is effectively accumulated in the C-shaped wire spring. Further, according to the present invention, since one and the other valve seats and the one and the other valves are provided at the end of the cylinder body on the cylinder head side via the valve seat mounting portion, the piston diameter and the cylinder diameter can be reduced. it can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of a reciprocating switching device for a pump according to the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG. 11 ... Cylinder body, 12 ... Cylinder head, 14 ...
Valve seat mounting part, 21 ... piston, 23 ... engagement part,
25,34… Valve seat, 27,31… Valve, 28… Shaft, 41… Spring fitting part, 43… Wire spring, 44… Back part, 45… Ends, 46… Valve operating body, 56 ... Switching rod, 58, 59 ... Working air chamber, 64 ...
Air supply port, 69 ... air chamber.

Claims (1)

(57) [Claims] A cylinder head is provided at one end of the cylinder body, a single rod type piston is slidably fitted inside the cylinder body, and a valve seat mounting part is integrally provided at the cylinder head side end of the cylinder body. An air supply port is communicated with one of the working air chambers located on the rod side of the piston in the cylinder body and an air chamber located on the cylinder head side of the valve seat mounting portion. One valve seat is provided on a surface facing the other, the one valve seat is communicated to the outside, and the other valve seat is provided on a cylinder head side surface at a valve seat mounting portion, and the other valve seat is provided. The seat is communicated with the other working air chamber formed between the valve seat mounting portion and the piston, and one valve seat is in contact with one valve seat. The one valve is provided with one valve, and the other valve, which is freely contactable and detachable from the other valve seat, is integrally provided by a shaft portion penetrating the valve seat mounting portion. One valve has a valve seat mounting portion. A valve operating body, which is axially movable in the center, is movably fitted within a certain range in the axial direction, and both ends of the valve operating body are engaged. A spring is provided for moving the body to one side and the other side in the axial direction by a snap action, and a switching rod for transmitting the movement of the terminal end of the movement of the piston to the rod side to the valve operating body is provided inside the valve operating body. For a pump, which is movably fitted and provided with an engaging portion at the center of the piston for transmitting the movement of the end of movement of the piston toward the cylinder head to the bubble operating body. A backward switching device, wherein a substantially C-shaped wire spring is formed as the spring by bending both ends in directions opposite to each other with respect to a rear portion located at the center of the wire. The wire spring is rotatably fitted to a spring fitting portion provided integrally with the valve seat mounting portion, and both ends of the wire spring are formed in a lateral hole formed in the valve operating body in the central portion. A reciprocating motion switching device for a pump, which is rotatably fitted to the device.