JPH0639101Y2 - Plunger pump - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a plunger pump, and more particularly to a plunger pump that is lightweight and compact and is capable of adjusting a small discharge amount.

[Description of the Related Art] A plunger pump is configured to rotate and slide a plunger to open and close an inlet of the pump to suck and discharge a fluid. In order to rotate the plunger, a worm wheel or a worm gear is provided on the outer periphery of the plunger, and the worm wheel or the worm gear is engaged with the worm that rotates in conjunction with the crankshaft.

Also, in order to slide the plunger, an end face cam with unevenness in the axial direction is formed at the tip of the plunger, the plunger is pressed toward the end face cam side by a spring, and the end face cam is held on the main body by a control pin. To make the plunger slide along the end cam when the plunger rotates (Japanese Patent Publication No. 53-25124).
No. or Jitsuko Sho 55-24374).

[Problems to be Solved by the Invention] Conventionally, the rotation from the crankshaft to the worm has been transmitted through a speed reducer. This is because if the rotation of the crankshaft is directly transmitted to the plunger, the discharge capacity becomes large and the minute flow rate cannot be adjusted. In such a speed reducer, the worm is conventionally supported by the body. As a result, the body has a tubular part that holds the plunger rotatably and slidably, and a hump-shaped part that holds the worm at right angles to the central axis of the tubular part and that has a worm holding axis that does not intersect. It has been made into a shape. In the body having such a shape, there is a problem that it is difficult to cast, the machining of the bore and the worm holding portion is troublesome, and the cost becomes high.

[Purpose of the Invention] The present invention has been made in view of the above points. The body is simplified by not supporting the worm on the body, the mounting space is made small, and a minute flow rate can be discharged. It is intended to provide a lightweight and inexpensive plunger pump.

[Means for Solving the Problems] In order to achieve the above object, the present invention forms a worm that rotates with the rotation of an engine crankshaft, a bore, and a suction port and a discharge port that communicate with the bore. A body, a plunger which is rotatably and slidably mounted in a bore of the body and has a pump chamber therein which can communicate with the suction port and the discharge port, and an axial end portion of the plunger. An end cam having an uneven surface in the axial direction, a worm gear that is provided on the outer periphery of the plunger and engages with the worm, a biasing means that biases the plunger toward the end surface, and the plunger. In a plunger pump having a control pin that comes into contact with the end face cam, the worm is directly connected to the crankshaft, and the worm is not held by the body. Then, the plunger is cantilevered on the body so that the end face cam side is the free end, the worm gear is attached to the outer periphery of the plunger near the free end, and the body is located at the rotation center axis position of the plunger. A hole is formed from the end face on the support side to the pump chamber, a sub-plunger attached to the body is inserted into the hole, and the plunger is rotated about the sub-plunger.

[Operation] The worm is directly connected to the crankshaft and should not be held by the body. On the other hand, the plunger should be cantilevered on the body. This allows the body to have a simple shape that allows resin molding to hold only one end of the plunger.

Further, the rotation speed of the plunger increases because the worm is directly connected to the crankshaft, but the discharge flow rate is adjusted by the diameter of the sub-plunger protruding into the pump chamber. Since it is possible to exchange the sub-plunger with a smaller diameter, it is possible to discharge a minute flow rate.

[Embodiment] Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a plunger pump according to the present invention. The body 10 has a tubular shape with both ends open and has a bore 12 inside, and one end of the bore 12 is liquid-tightly closed by a plug 14. A sub-plunger 16 is fixed to the bore 12 side of the plug 14. Body 10
A suction pipe 22 and a discharge pipe 24 having a suction passage 18 and a discharge passage 20 communicating with the inside of the bore 12 are integrally formed therewith. A branch passage 26 branches off from the middle of the suction passage 18.
This branch passage 26 introduces fluid into the bore 12 between the plug 14-side end surface of the plunger, which will be described later, and the plug 14. By filling this area with the fluid, the plunger is stably slid. I am trying to move.

One end of the plunger 28 is rotatably and slidably mounted in the bore 12 of the body 10, and the other end is a free end protruding from the body 10. The tip of the plunger 28 on the insertion side into the body 10 has a hole along the center axis of rotation.
30 is formed, and the sub-plunger 16 is inserted into the hole 30. Further, a fuel passage 32 is formed from the outer circumference of the plunger 28 toward the axial center at a position where it can communicate with the suction passage 18 and the discharge passage 20, and the fuel passage 32 and the hole
32 communicates with the pump chamber 34. The sub-plunger 16 can be projected into the pump chamber 34. An annular dent portion 36 is formed on the outer circumference of the plunger 28 at a position where it is inserted into the body 10, and a leak preventing V ring 38 is mounted in the dent portion 36.

An annular worm gear 40 around the free end of the plunger 28.
Is fixed. On the end surface of the worm gear 40, there is formed an end surface cam 42 which is uneven in the axial direction.

The worm 46 engaging with the worm gear 40 is directly connected to the crankshaft 44 (broken line) of the engine. The worm 46 is independent of the body 10, that is, the body 10
It is in a state where it is not held by.

A clip 48 is fixed to the base of the plug 14, and a spring 50 is provided between the clip 48 and the end surface of the plunger 28 on the plug 14 side. It is always biased to project.

An arm 52 extending to the tip of the worm gear 40 is integrally formed on the body 10 on the free end side of the plunger 28, and a cylindrical control pin 56 having a cam 54 formed at the tip is screwed into the arm 48. There is. The plunger
The end face cam 42 at the tip of 28 is always in contact with the side face of the cylindrical control pin 56 by the spring 50. Further, a protrusion 58 capable of contacting the cam 54 of the control pin 56 is formed at the center of the free end surface of the plunger 28. The cam 54 of the control pin 56 is shaped so that the distance between the cam 54 and the protrusion 58 of the cam 54 changes when the control pin 56 is rotated. If the position of the cam 54 is changed so that the distance between the cam 54 and the protrusion 58 is changed, the contact point is changed from the control pin 56 and the end face cam 42 to the protrusion during the rotation of the plunger 28. By moving to 58 and the cam 54, the stroke of the plunger 28 can be changed.

In the plunger pump configured as described above, the plunger 28 is rotated by the rotation of the worm 46, and the plunger 28 is slid by the action of the end surface cam 42 at that time. By the rotation and sliding of the plunger 28, the fluid from the suction passage 18 is introduced into the pump chamber 34 of the plunger 28, and then the fluid of the pump chamber 34 is discharged.
Is discharged more.

In this plunger pump, since the worm 46 is directly connected to the crank shaft 44, the rotation speed of the plunger 28 increases. Since the flow rate of the pump is determined by the shaft diameter × stroke, the flow rate can be adjusted by changing the length and diameter of the sub-plunger 16 which is inserted into the plunger 28 and reaches the pump chamber 34.

Therefore, even when it is desired to set the flow rate to a very small amount, it can be adapted by appropriately selecting the length and the diameter of the sub-plunger 16.

[Advantages of the Invention] As described above, according to the plunger pump of the present invention, the worm is directly connected to the crankshaft, and the worm is not held by the body. The worm is engaged with and the plunger is rotated around the sub-plunger.

As a result, both the worm directly connected to the crankshaft and the worm gear attached to the free end side of the plunger can be located outside the body, so the body should have a simple and compact shape that can only be used to cantilever the plunger. You can As a result, the body can be made of resin, the body can be easily cast and the bore can be processed, and the manufacturing cost can be significantly reduced.

In addition, the flow rate can be finely adjusted by changing the diameter of the sub-plunger that communicates with the pump chamber, effectively connecting the worm to the crankshaft.

Furthermore, by locating the sub-plunger on the rotation center axis of the plunger, the diameter of the plunger can be reduced, and the plunger pump can be further downsized. In this way, by making the body a simple and small shape, the mounting space for the body is small, and the extra space can be used.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a plunger pump according to the present invention. 10 …… Body, 12 …… Bore, 14 …… Sub-plunger, 18 …… Suction passage, 20 …… Discharge passage, 28 …… Plunger, 30 …… Hole, 34 …… Pump chamber, 40 …… Worm gear , 42 …… end cam, 44 …… crankshaft, 46 …… worm, 50 …… spring, 56 …… control pin.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A worm that rotates with rotation of a crankshaft of an engine; A plunger having a pump chamber inside which is mounted and is capable of communicating with the suction port and the discharge port, an end face cam provided at an end portion of the plunger in the axial direction and having irregularities in the axial direction, and a plunger of the plunger. A worm gear that is provided on the outer periphery and engages with the worm,
Urging means for urging the plunger toward the end face side,
A plunger pump having a control pin that comes into contact with an end face cam of the plunger, wherein the worm is directly connected to a crankshaft, and the worm is not held by a body, and the end face cam side is a free end. The jar is held by a cantilever on the body, the worm gear is attached to the outer periphery of the plunger near the free end, and a hole is formed from the end surface on the body supporting side to the pump chamber at the rotation center axis position of the plunger, A plunger pump characterized in that the sub-plunger attached to the body is inserted into the hole and the plunger is rotated around the sub-plunger.