JPH0346232Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to plunger pumps, and in particular to a plunger pump in which the control pin has a simple structure to reduce costs, and the stroke of the plunger can be easily adjusted. Regarding pumps.

[Description of Prior Art] A plunger pump is a device that rotates and slides a plunger to open and close an inlet/outlet of the pump to suck in and discharge fluid. To rotate this plunger,
A worm gear is attached to the outer periphery of the plunger, and a worm connected to the crankshaft is engaged with the worm gear.

Further, in order to make the plunger slide, one tip of the plunger is provided with an annular end cam having unevenness in the axial direction, a biasing means is provided for pressing the plunger toward the end cam, and the end cam is held in the main body. The plunger is always brought into contact with a control pin, and as the plunger rotates, the plunger slides according to the shape of the end cam (Japanese Patent Publication No. 53-25124 and Utility Model Publication No. 55-24374).

To change the flow rate of this type of pump,
Conventionally, this has been done by adjusting the sliding stroke of the plunger. That is, a protrusion is provided at the center of the annular end cam, and cam surfaces are formed on the outer peripheral surface of the tip of the control pin that contacts the protrusion with different radii from the rotation center axis. With this configuration, the end cam is brought into contact with the control pin near the maximum protrusion of the end cam, but when the contact point moves to the minimum protrusion of the end cam, the protrusion is brought into contact with the control pin. Make contact with the cam surface at the tip, but do not allow the end cam to contact the control pin. As a result, by rotating the control pin so as to change the radius of the cam surface that contacts the projection, the stroke of the plunger can be changed and the flow rate can be adjusted.

[Problems to be solved by the invention] Conventionally, in order to change the stroke of the plunger, cam surfaces with different radii have been formed on the outer peripheral surface of the tip of the control pin. However, manufacturing this cam surface was expensive. Furthermore, if the rotation angle of the control pin is not adjusted accurately, the stroke of the plunger will change and the desired flow rate cannot be obtained, so it is necessary to accurately adjust the rotation angle of the control pin.

[Purpose of the invention] The present invention was made in view of the above points, and its purpose is to provide a plunger pump whose control pin can be manufactured at a lower cost and whose stroke can be changed easily and accurately. It is something.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a worm that rotates with the rotation of the engine crankshaft, a bore, and an inlet and an outlet that communicate with the bore. a plunger that is rotatably and slidably mounted in a bore of the body and has a pump chamber therein that can communicate with the suction port and the discharge port, and a plunger that is connected to the worm provided on the outer periphery of the plunger. an annular end cam provided at the end of the plunger and having unevenness in the sliding direction; a protrusion provided at the annular center of the end cam; In the plunger pump, the plunger pump has a biasing means for biasing, and a control pin that contacts the end cam and the protrusion and is attached to the body, and the control pin is rotatably and slidably attached to the body, and the control pin is rotatably and slidably attached to the body. The diameter of the portion that contacts the protrusion is configured to change with displacement in the longitudinal direction, and a plurality of stepped surfaces having different heights are formed around the control pin insertion position on the side facing the end face cam of the body. death,
The control pin is provided with a penetrating pin that is hooked to the step surface thereof, and is provided with biasing means for constantly bringing the penetrating pin into contact with the step surface.

[Operation] The direction of the sliding axis near the tip of the control pin is tapered. Penetration pins fixed to the control pins are hooked to a plurality of steps of the body at different heights depending on the flow rate. As a result, the position of the control pin protruding in the axial direction of the plunger is different, and the position of the tip end taper of the control pin that contacts the protrusion of the plunger is different. Since the tapered end portions of the control pins have different radii from the shaft center, the stroke of the plunger can be changed.

[Example] Next, the present invention will be explained based on 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 cylindrical shape with a bore 12 inside.
One end is closed in a fluid-tight manner by a plug 14. A sub-plunger 16 is fixed to the bore 12 side of the plug 14. In body 10,
A suction passage 18 and a discharge passage 20 communicating with the inside of the bore 12
A suction pipe 22 and a discharge pipe 24 are integrally formed.

The plunger 26 has one end rotatably and slidably mounted in the bore 12 of the body 10,
The other end is a free end protruding from the body 10. A hole 28 is formed at the end of the plunger 26 on the insertion side into the body 10, and extends along the rotation center axis thereof. The sub-plunger 16 is inserted into the hole 28. Further, a passage 30 is provided at a position that can communicate with the suction passage 18 and the discharge passage 20 from the outer periphery of the plunger 26 toward the axial center.
A pump chamber 32 is formed at a position where the passage 30 and the hole 28 intersect. A clip 34 is fixed to the base of the plug 14,
A spring 36 is provided between the clip 34 and the end surface of the plunger 26 on the plug 14 side, and the spring 36 urges the plunger 26 to always protrude toward the free end.

An annular worm gear 38 is fixed to the outer periphery of the free end of the plunger 26. This worm gear 38 is engaged with a worm 42 that is directly connected to a crankshaft 40 (broken line) of the engine. An annular end cam 44 having projections and depressions in the axial direction is formed on the end surface of the worm gear 38 . A protrusion 46 is integrally formed with the plunger 26 at the annular center position of the end cam 44 so as to protrude outward from the lowest position of the end cam 44.

A thick plate 48 extending to the tip of the worm gear 38 is integrally formed on the body 10 at the free end side of the plunger 26. A hole 50 is formed in this plate 48, and a control pin 52 is slidably and rotatably inserted into this hole 50. Worm gear 3 of the plate 48
On the 8 side surface, a plurality of stepped surfaces 5 having different heights are formed around the hole 50 of the control pin 52.
4, 56, 58, etc. are formed. The control pin 52 is tapered near the tip 60, with the tip having a small diameter and increasing in diameter as it progresses in the sliding direction. The protrusion 46 is set to contact the tip 60 of the control pin 52, and the annular end cam 44 is set to contact a portion of the control pin 52 having the same large diameter other than the tip 60.

A penetrating pin 62 is fixed in the longitudinal direction of the control pin 52 in a direction perpendicular to its axis, and the penetrating pin 62 is located on the stepped surface side of the plate 48 . A clip 64 is fixed to the root side of the control pin 52, that is, to the side opposite to the stepped surface of the plate 48. A spring 66 is provided between the clip 64 and the plate 48, and the spring 66 control pin 5
2 is biased in a direction to move toward its base. Therefore, the penetrating pin 62 is brought into contact with one of the plurality of step surfaces of the plate 48.

Here, when the heights of the plates 48 are shown in FIG. 3 in the order of a to b to c to d in FIG. This becomes the section 58.

Next, adjustment of the stroke of the plunger 26 will be explained. First, this control pin 52
When moving the through pin 62 from the first step surface to the next step surface, the control pin 52 is moved by the spring 66.
Push the penetrating pin 62 toward the tip side against the force to remove contact with the first stepped surface of the penetrating pin 62. Thereafter, the control pin 52 is rotated to align the through pin 62 with the next step surface. In this way, by changing the position of the through pin 62 from one step surface to the other step surface,
The control pin 52 can be slid in a direction perpendicular to the sliding direction of the plunger 26. As a result, the stroke of the plunger 26 can be changed by changing the contact position of the taper of the tip 60 of the control pin 52 with the protrusion 46.

Note that the number of stepped surfaces is not limited as long as it is plural. It is also possible to use the spring 66 as a compression/torsion spring to urge the through pin 62 toward a higher step position, thereby preventing the through pin 62 from moving to a lower step surface.

[Effects of the invention] As described above, according to the plunger pump according to the invention, a plurality of stepped surfaces of different heights are provided around the control pin holding position of the body, and a plurality of step surfaces attached to the control pin are provided around the control pin holding position of the body. The penetrating pin is brought into contact with the step surface by a biasing means, so that the sliding protrusion position of the control pin can be changed. As a result, the stroke of the plunger can be adjusted using a simple structure in which the tip of the control pin is simply tapered in the sliding direction. Therefore, there is no need to form a cam surface on the outer periphery of the tip of the control pin as in the conventional case, and manufacturing costs can be reduced.

In addition, the stroke can be adjusted by simply placing a through pin on a predetermined step surface, making the operation easy and allowing accurate stroke setting.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing one embodiment of the plunger pump according to the present invention, Fig. 2 is a plan view of the plate of the body shown in Fig. 1 in the direction of arrow A, and Fig. 3 is a cross-sectional view showing the points a to d in Fig. 2. It is a graph showing the height of a plate. 10...Body, 12...Bore, 18...Suction passage, 20...Discharge passage, 26...Plunger, 32...Pump chamber, 36...Spring, 38...
Worm gear, 40...Crankshaft, 42...Worm, 44...End cam, 46...Protrusion, 52
... Control pin, 54, 56, 58 ... Stepped surface, 60 ... Tip, 62 ... Penetration pin, 66
...Spring.

Claims (1)

[Scope of utility model registration request] A worm that rotates as the engine crankshaft rotates, a body that has a bore, an inlet port and a discharge port that communicate with the bore, and a body that is rotatably and slidably mounted inside the bore of the body. A plunger having a pump chamber that can communicate with the suction port and the discharge port, an engaging means provided on the outer periphery of the plunger to engage with the worm, and an engaging means provided at the end of the plunger and having unevenness in the sliding direction. an annular end cam, a protrusion provided at the annular center of the end cam, biasing means for biasing the plunger toward the end cam, and a control attached to the body in contact with the end cam and the protrusion. In the plunger pump having a pin, the control pin is rotatably and slidably attached to the body, and a portion of the control pin that contacts the protrusion is configured to have a diameter that changes with displacement in the longitudinal direction, A plurality of step surfaces with different heights are formed around the control pin insertion position on the side facing the end face cam of the body, and a through pin that is hooked to the step surface is provided on the control pin. A plunger pump characterized by being equipped with a biasing means for constantly contacting a step surface.