JP2545632B2 - Reciprocating pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a reciprocating pump, and more particularly to a reciprocating pump that can be used without a check valve.

(Prior Art) Conventionally, as the reciprocating pump of this type, there is, for example, the invention described in Japanese Patent Laid-Open No. 64-41679 by the present applicant.

That is, as shown in FIG. 4, this conventional one has a piston 8 fitted in a cylinder 1 having a suction port 2 and a discharge port 3 on its peripheral wall so that the piston 8 can reciprocate while rotating. The outer peripheral surface of 8 is provided with a suction hole 24 and a discharge hole 25 which communicate with the pump chamber 16 in the cylinder 1 through a conduction hole 23 formed in the tip surface of the piston 8.
The suction hole 24 is arranged so as to be in face-to-face communication with the suction port 2 of the cylinder 1 when the piston 8 is retracted, and the discharge hole 25 is so as to be face-connected to the discharge port 3 of the cylinder 1 when moved forward.

By reciprocating the piston 8 while rotating it, the fluid in the pump chamber 16 is sucked and discharged. According to this, a separate check valve is not required.
There is an advantage that the structure of the pump itself can be simplified.

(Problems to be Solved by the Invention) In this type of pump, it is necessary to provide a seal to prevent fluid leakage between the cylinder 1 and the piston 8, but the piston 8 is not limited to reciprocating motion. Since the O-ring cannot rotate and slide, the fluid cannot be prevented from leaking. Therefore, conventionally, the seal has been achieved by minimizing the clearance between them.

Thus, in order to reduce the clearance in this way, it is sufficient to improve the processing accuracy, but this also has a certain limit, and there is a great problem that the processing cost and the like increase significantly. It was.

Further, when the sliding surface of each member is damaged during use, it is extremely difficult to maintain a sufficient sealing effect even if the sliding surface is repaired again.

Therefore, the present invention has been made in order to solve the above-mentioned conventional problems, and while maintaining the advantages of the prior art, a sealing property capable of satisfactorily preventing fluid leakage from the pump chamber by an extremely simple means. It is an object to provide an excellent reciprocating pump.

(Means for Solving the Problem) That is, the means adopted by the present invention for solving the above problem is that the tip end is eccentric from the axial center in the cylinder 1 having the suction port 2 and the discharge port 3. A cylindrical body 4 having a through hole 5 bored in its surface is fitted therein, and a piston 8 is inserted in the cylindrical body 4.
Is provided so as to reciprocate while rotating, and moreover, the conducting hole 5 of the cylindrical body 4 is brought into conduction with the suction port 2 of the cylinder 1 when the piston 8 moves backward, and the discharge of the cylinder 1 occurs when the piston 8 moves forward. The cylinder 4 is configured to rotate together with the piston 8 so as to be electrically connected to the outlet 3, and the fluid discharged from the discharge port 3 so as to bring the tip end surface of the cylinder 4 into contact with the cylinder 1. It is a point that a pipe capable of branching and supplying a part is provided at the discharge port 3 so that the cylindrical body 4 is pressed against the cylinder 1 side by the fluid.

(Operation) Therefore, in the reciprocating pump having the above-mentioned configuration, when the piston 8 is retracted with rotation, the piston 8
Since the conduction hole 5 of the cylindrical body 4 rotating together with the suction port 2 of the cylinder 1 is brought into face-to-face conduction, fluid is sucked from the suction port 2 through the conduction hole 5 into the cylinder 4, and the piston 8
At the time of forward movement accompanied by rotation, the cylindrical body 4 rotates and the conduction hole 5 thereof is brought into face-to-face conduction with the discharge port 3 of the cylinder 1.
The fluid sucked into the cylindrical body 4 is discharged from the discharge port 3,
Appropriate pump operation can be performed.

In this case, between the cylinder 1 and the piston 8,
Since the tubular body 4 that rotates together with the piston 8 is interposed, the piston 8 that reciprocates while rotating is the tubular body 4
It only reciprocates in relation to the piston 8
As for the seal between the cylinder body 4 and the cylinder 4, it is sufficient to consider only such reciprocal sliding, and the seal between the cylinders 1 only needs to consider the rotation and sliding of the cylinder 4 and to seal between them. is there.

Further, the cylinder 4 is pressed toward the cylinder 1 by a part of the fluid discharged from the discharge port 3 through the pipe, and the tip end surface of the cylinder 4 comes into contact with the cylinder 1. Fluid leakage can be effectively prevented.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a cylinder composed of a cylindrical cylinder body 1a and a bushing 19 connected to one end of the cylinder body. The cylinder 1a communicates with a suction port 2 provided at a tip end surface of the bushing 19 and has a suction hole. 18 is formed so as to penetrate therethrough in the axial direction, and a discharge hole 17 is formed in a bent shape so as to communicate with the discharge port 3 provided on the peripheral wall.

Reference numeral 4 denotes a cylindrical body having a substantially frustoconical tip portion, and an elongated hole-like communication hole 5 communicating with the pump chamber 16 is formed in the inclined surface in the circumferential direction as shown in FIG. It is rotatably and slidably fitted in the cylinder 1 so that the conduction hole 5 communicates with the discharge hole 17 or the suction hole 18 of the cylindrical body 4. Reference numerals 6 and 6 denote long grooves formed on the inner peripheral surface of the one end side of the cylindrical body 4 so as to face each other with a desired length in the axial direction.

Reference numeral 8 denotes a piston fitted in the cylindrical body 4 so as to be reciprocally slidably and rotationally slidable, and a pin 9 projecting from the circumferential surface of the piston rod 22 is fitted in the long grooves 6, 6 of the cylindrical body 4. Then, when the piston 8 is rotationally driven, the cylindrical body 4 is rotated together. That is, the cylindrical body 4 can rotate only, and the piston 8 can rotate and reciprocate. Reference numeral 21 denotes an O-ring fitted in a groove provided on one end side of the piston 8.

In addition, a part of the fluid discharged from the discharge port 3 is branched and supplied, and the discharge pressure of the fluid causes the 1b of the collar portion of the cylinder body 1a to be supplied.
The cylinder body 1a and the discharge port 3 are connected by a pipe so that the upper surface of the cylinder can be pressed downward.

FIG. 3 shows an example of a pump drive mechanism.
Indicates a gear-shaped cam follower fixed to one end of the piston 8. Reference numeral 11 denotes a cylindrical cam rotatable by an electric motor 12, and a cam groove formed on a tooth 14 meshed with a tooth 13 formed on the outer circumferential surface of the cam follower 10 on the outer circumferential surface thereof so as to reciprocate while rotating the cam follower 10. 15 are formed.

The shape of the cam groove 15 of the cylindrical cam 11 is set so that the cam follower 10 and the piston 8 make one rotation while performing one reciprocating motion, and the cylinder 4 rotates and the piston 8 rotates. While moving forward, a discharge stroke in which the piston 8 reaches bottom dead center and continues to rotate only together with the cylinder 4, a suction stroke in which the cylinder 4 rotates and the piston 8 moves backward while rotating, and a piston 8 is formed so as to reach the top dead center and to carry out a switching process in which only the rotation operation is continued together with the cylindrical body 4.

Further, the conduction hole 5 formed in the cylindrical body 4 is arranged so as to be in face-to-face conduction with the suction port 2 on the cylinder 1 side when the piston 8 retracts, and the discharge port on the cylinder 1 side when the piston 6 retracts. 3 are arranged so as to be face-to-face with 3 and communicate with the pump chambers 16 in the cylindrical body 4, respectively.

Since the reciprocating pump P according to the present invention is configured as described above, when the piston 8 first rotates and retracts in the direction of the arrow A, the cylindrical body 4 also rotates while the cylindrical body 4 rotates in the same manner.
The conducting hole 5 is electrically connected to the suction port 2 on the cylinder 1 side, and the other discharge port 3 is closed by the tip surface of the cylindrical body 4. Therefore, from the suction port 2 through the conduction hole 5 to the pump chamber
Fluid can be sucked into 16. At this time, since the conduction hole 5 is formed in the shape of a long hole in the circumferential direction, the conduction state between the conduction hole 5 and the suction port 2 is maintained over substantially the entire suction stroke of the piston 8. Become.

Then, after the piston 8 reaches the top dead center, the piston 8 does not immediately move forward and continues to rotate only together with the cylindrical body 4, so that the suction port 2 is moved to the outer peripheral surface of the cylindrical body 4. A state is prepared in which the conduction hole 5 is electrically connected to the discharge port 3 while being closed. That is, due to the presence of this switching process, it is possible to avoid the piston 8 from immediately starting to move forward while the conduction state between the conduction hole 5 and the suction port 2 is not released, and the fluid in the pump chamber 16 is discharged. It does not cause inconvenience such as backflow to the 3 side.

After that, when the piston 8 advances in the B direction, the conduction hole 5 of the rotating cylinder body 4 conducts face-to-face with the discharge port 3 of the cylinder 1, while the suction port 2 is at the tip surface of the cylinder body 4. The cylinder 1 is closed and allows the fluid in the pump chamber 16 to pass through the through hole 5.
It is possible to discharge from the discharge port 3. The pump operation is performed by repeating the suction stroke, the switching stroke, and the discharge stroke.

In this case, between the cylinder 1 and the piston 8,
Since the cylindrical body 4 that rotates together with the piston 8 is interposed, the piston 8 that reciprocates while rotating only reciprocates in relation to the cylindrical body 4. Therefore, the seal between the piston 8 and the cylindrical body 4 is generated. It suffices to consider only such reciprocal sliding, and the sealing between the cylinders 1 may be performed by considering only the rotational sliding of the cylindrical body 4 and providing sealing means between them. Therefore, for example, an O-ring may be inserted in the seal between the cylinder 4 and the cylinder 1.
Therefore, strict machining accuracy is not required to secure the clearance between the piston 8 and the piston 8, and it is not necessary to separately perform finish machining.

Further, when the conduction hole 5 is provided at the tip end portion of the tubular body 4 as in the embodiment, the tubular body 4 abuts and rotates on the upper surface of the bushing 19 while being pressed in the discharge process. That is, since the conduction hole 5 of the cylindrical body 4 and the discharge hole 17 of the bushing 19 are brought into face-to-face conduction with each other under a constant pressing force, the leakage of the fluid between the two is well prevented and the fluid is prevented. Can be discharged. In particular, there is an advantage that so-called bypass backflow that occurs between the suction port 2 and the discharge port 3 can be prevented when the discharge pressure becomes high.

Further, since a part of the fluid discharged from the discharge port 3 is branched and supplied so as to axially press the upper surface of the collar portion 1b of the cylinder body 1a, the fluid is discharged through the collar portion 4a of the cylinder body 4 through the collar portion 4a. The cylindrical body 4 comes into contact with the bushing 19 in a pressed state,
Therefore, there is an advantage that the leakage of the fluid between the both can be prevented better. Since this pressing force fluctuates according to the level of the discharge pressure of the fluid, an appropriate pressing force can be obtained according to the discharge state of the fluid, and the sliding surfaces of the cylinder body 1a and the cylinder body 4 are worn. Therefore, there is no inconvenience that the pressing force is lowered due to the above.

The circumferential dimension of the through hole 5 formed in the cylindrical body 4 is
While considering the reciprocating speed of the piston 8 and the rotating speeds of the piston 8 and the cylinder 4, it is possible to make arbitrary design changes according to the purpose of use of the pump. A through hole 5 is formed so as to be in face-to-face communication with the intake port 2 on the cylinder 1 side and also face-to-face with the discharge port 3 on the cylinder 1 side when the piston 6 moves forward so as to communicate with the pump chamber 16. Good.

Further, in the above embodiment, the cylindrical body 4 and the piston 8 are
Since a combination of a cylindrical cam mechanism and a gear mechanism is used as the driving means, there is an advantage that the structure is extremely simple, but the specific structure of the driving means is not limited.

Further, in the embodiment, the tip end portion of the cylindrical body 4 is formed in a substantially truncated cone shape, but it may be formed in a simple cylindrical shape, and its specific shape is not critical.

Further, in the above-described embodiment, the tip end surface of the cylinder body 4 is attached to the cylinder 1
A portion of the fluid discharged from the discharge port 3 was diverged and supplied via a pipe so as to press the upper surface of the collar portion 1b of the cylinder body 1a so as to come into contact with, but the present invention is by no means limited to this. In short, the pipe may be provided so that the front end surface of the cylindrical body 4 is pressed toward the cylinder 1 side by the fluid from the discharge port 3.

(Effects of the Invention) As described above, according to the present invention, the cylinder that rotates with the piston is interposed between the cylinder and the piston. Therefore, the piston that reciprocates while rotating has a relationship with the cylinder. Since it only reciprocates, therefore, the seal between the piston and the cylinder need only consider such reciprocal sliding, and the seal between the cylinders only needs to consider the rotary sliding of the cylinder. The seal can be easily applied.

Therefore, unlike the conventional one that uses a small clearance between the cylinder and the piston as the sealing means, strict machining accuracy is not required, and the manufacturing cost can be significantly reduced. In addition, a particularly remarkable effect that a good sealing state can be maintained was obtained.

Further, since a conduction hole is provided at an eccentric position on the tip end surface of the cylindrical body, the conduction hole should be face-to-face conductive with the discharge port of the cylinder while being pressed against the cylindrical body by the forward movement of the piston during discharge. Therefore, the pressing force can prevent the fluid from leaking, and the fluid can be satisfactorily discharged from the discharge port.

This makes it possible to prevent so-called bypass backflow that occurs between the suction port and the discharge port of the cylinder when the discharge pressure becomes high.

Further, a part of the fluid discharged from the discharge port is branched and supplied, and the discharge pressure of the fluid maintains the contact state between the tip end surface of the cylinder and the cylinder. The effect that leakage can be prevented more effectively is exhibited. Since this pressing force fluctuates according to the level of the discharge pressure of the fluid, an appropriate pressing force can be obtained according to the discharge state of the fluid, and due to wear of the sliding surface of the cylinder and the cylinder, etc. There is no such inconvenience that the pressing force decreases.

[Brief description of drawings]

 FIG. 1 is a partial sectional front view showing an embodiment of the present invention. FIG. 2 is a perspective view of a main part of the cylindrical body. FIG. 3 is an explanatory view showing an example of a driving means. FIG. 4 is a sectional view of an essential part showing a conventional example. 1 ... Cylinder, 2 ... Suction port, 3 ... Discharge port, 4 ... Cylindrical body, 5 ... Conductive hole, 8 ... Piston

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasuo Nakai 2-4-8 Minamisenba, Chuo-ku, Osaka-shi, Osaka Japan Feeder Industry Co., Ltd. (56) References Public Sho 62-26623 (JP, Y2)

Claims (1)

(57) [Claims] 1. A cylinder 1 having a suction port 2 and a discharge port 3, and a cylinder 4 having a through hole 5 eccentrically from the shaft center and bored in a tip end surface thereof is fitted into the cylinder 1. 4, a piston 8 is provided so as to reciprocate while rotating, and moreover, the conduction hole 5 of the cylindrical body 4 is electrically connected to the suction port 2 of the cylinder 1 when the piston 8 retracts, and Of the cylinder 1 so as to be electrically connected to the discharge port 3 of the cylinder 1 during forward movement of the cylinder 1, and the discharge port of the cylinder 4 is brought into contact with the cylinder 1 so that the tip end surface of the cylinder 4 contacts the cylinder 1. A reciprocating pump characterized in that a pipe capable of branching and supplying a part of the fluid discharged from No. 3 is provided at the discharge port 3 to press the cylinder 4 toward the cylinder 1 by the fluid.