JPH0437268Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The invention is a plunger-type oil pump that supplies oil to an engine that drives an industrial machine such as a chainsaw, and whose discharge amount is manually adjusted. The number of parts that make up the rotation axis to be adjusted is small,
The present invention also relates to a device in which the rotating shaft can be assembled to a pump housing using a snap action.

[Prior Art] FIG. 5 shows the configuration of a variable discharge amount pump disclosed in Japanese Patent Publication No. 46-24090. In the figure, a worm gear 2 is formed on the plunger 1 and meshes with a driving worm 3, so that the rotation of the driving worm 3 causes the plunger 1 to move into the cylinder 4.
Although not shown in the figure, the oil inlet and outlet openings on the inner surface of the cylinder 4 are opened and closed, and at the same time, the lead cam 5 formed on the end face of the plunger 1 and the guide Due to the contact with the pin portion 6, it reciprocates and performs a pumping action. On the other hand, a protrusion 7 is formed at the end of the plunger 1, and when it comes into contact with a cam part 8 formed integrally with the guide pin part 6, the reciprocating length of the plunger 1 is limited. By operating a rotating shaft 9 consisting of a rotating shaft 6 and a cam portion 8 with a rotating lever 10, the discharge amount can be adjusted. In the oil pump configured as described above, the rotary shaft 9 or the rotary lever 10 is generally biased in a direction to reduce the discharge amount, and the discharge amount is adjusted in conjunction with the throttle valve lever of the carburetor.

FIG. 6 shows a conventional configuration of an oil pump in which the discharge amount is manually adjusted by the oil pump alone without interlocking with engine operation. Code 1 in the diagram
9 to 9 indicate the same parts as in Figure 5,
11 is a spring that biases the rotating shaft 9 in the axial direction;
12 is a pin that receives the force of the spring 11.
A driver groove 13 is provided on the end surface of the rotation shaft 9,
The discharge amount is adjusted by rotating the rotating shaft 9 with a driver. The pin 12 is pressed against the surface of the casing 14 by the force of the spring 11, and due to the friction between the pin 12 and the surface of the casing 14, the rotating shaft 9 is rotated by engine vibration. This will be prevented.

[Problems with the Prior Art] The plunger type oil pump shown in FIG. 6, which manually adjusts the amount of oil discharged, requires a spring 11, a clip 15 for receiving the spring 11, and a pin 12 in addition to the rotating shaft 9. The number of parts is large, which not only increases the number of assembly steps, but also increases the length of the rotation shaft 9 protruding from both sides of the housing 14, which is inconvenient in terms of outfitting.

[Means for Solving the Problems] The use of the spring 11 and pin 12 for axial positioning of the rotating shaft 9 and for preventing rotation of the rotating shaft 9 is discontinued. Therefore, (1) The rotation shaft 9 is made of synthetic resin.

(2) The diameter of both ends of the rotating shaft 9 that protrude beyond the shaft hole of the housing 14 that forms the bearing of the rotating shaft 9 is made larger than the diameter of the shaft hole, thereby positioning the rotating shaft 9 in the axial direction.

(3) A slotted groove passing through the center of the rotating shaft 9 from one end surface toward the center of the rotating shaft 9 is provided so that the diameter can be elastically reduced when inserted into the shaft hole.

(4) A sliding groove is provided eccentrically from the other end surface toward the center of the rotating shaft 9, a thin walled portion including a small circular arc is formed, and a protrusion is provided on the arc-shaped surface of the outer periphery of the thin walled portion,
The protrusion is elastically engaged with a groove formed in the housing opposite to the protrusion to prevent rotation.

[Structure of the invention] A plunger is disposed in a cylinder in which an oil inlet and an oil outlet open on the inner circumferential surface, and which opens and closes the inlet and outlet through rotational motion and performs a pumping action by reciprocating. A lead cam is formed on the peripheral edge of the end face of the plunger, and a protrusion is formed at the center; a guide pin portion that comes into contact with the lead cam and provides reciprocating motion to the plunger in conjunction with the rotational movement of the plunger; and the protrusion. A rotating shaft integrally formed with a cam portion that contacts the cylinder and limits the length of the reciprocating motion is disposed perpendicularly to the cylinder and penetrates the pump housing, and the rotation of the rotating shaft In the plunger type oil pump with a variable discharge amount, which can adjust the discharge amount of oil, the rotating shaft is made of a flexible synthetic resin material, and the rotating shaft is adjacent to the guide pin portion and the cam portion, respectively. A shaft neck that can freely rotate inside the shaft hole of the housing is formed,
A large diameter portion having a diameter larger than the diameter of the shaft neck is formed adjacent to the outer end side of each of the shaft necks, and engages with the outer end surface of the shaft hole to adjust the axial position of the rotation shaft. determine,
A slotted groove passing through the center from the end face of one of the large diameter parts toward the center of the rotation shaft is provided to enable the large diameter part to be inserted into the shaft hole, and A driver groove for rotating the rotating shaft with a driver is formed on the end face of the large diameter portion, and a slotted groove extending from the end face toward the center of the rotating shaft is eccentrically provided in the large diameter portion. A thin wall portion including a small arc is formed, a projection is provided on an arcuate surface of the outer periphery of the thin wall portion, and the projection is elastically engaged with one of the plurality of engagement grooves formed in the housing in opposition to the projection. The rotating shaft can be fixed at a desired angular position by engaging with the rotating shaft.

[Example] Fig. 1 is a longitudinal sectional view of a plunger type oil pump according to the present invention which manually adjusts the discharge amount, in which reference numeral 1 is a plunger, 2 is a worm gear, and 3 is a plunger type oil pump.
4 is a driving worm, 4 is a cylinder, 5 is a lead cam, 6 is a guide pin part that comes into contact with the lead cam, 7 is a projection, 8 is a cam part that comes into contact with the projection, and 9 is a combination of the guide pin part 6 and the cam part 8. The rotating shaft 9 is integrally formed, as in the case of FIGS. 5 and 6, but in the configuration of the present invention, the rotating shaft 9 is made of a synthetic resin material such as nylon, Diuracon, or PBT. The thinner parts are made of a material that provides flexibility. Reinforcements can also be mixed and molded to increase strength. 16 and 17 are shaft neck portions of the rotation shaft 9, which are integrally formed adjacent to the guide pin portion 6 and the cam portion 8, respectively, and are supported by shaft holes 18 and 19 opening in the housing 14. Ru. In the embodiment shown in FIG. 1, the shaft neck portion 16 is formed to have the same diameter as the guide pin portion 6. Reference numerals 20 and 21 are large diameter portions that are formed outside the shaft holes 18 and 19 adjacent to the shaft neck portions 16 and 17, respectively, and have a larger diameter than the shaft holes 18 and 19, respectively. By pinching the outer end surfaces of and 19, the rotation shaft 9 is positioned in the axial direction. Since one of the large diameter portions 21 is provided with a slot 22 passing through the center from the outer end surface toward the center of the rotation shaft 9, the large diameter portion 21
1 is inserted into the shaft hole 19, the diameter can be elastically reduced. The slot grooves 22 may be formed radially from the center toward the outer circumference, or may be formed along one diameter. Further, the large diameter portion 21 can be easily inserted into the shaft hole 19 by tapering the diameter toward the outer end in a conical shape. In addition to a driver groove 13 for rotating the rotation shaft 9 with a driver, the other large diameter portion 20 has a large sliding groove 23 extending from the end surface toward the center of the rotation shaft 9. A thin wall portion 24 is provided eccentrically with respect to the diameter portion 20 and includes a small circular arc, and a projection 25 is provided on the arcuate surface of the outer periphery of the thin wall portion 24. A plurality of engagement grooves 26 that engage with the protrusions 25 are provided, and the rotation shaft 9 is rotated to a position where the protrusion 25 engages with any of the engagement grooves 26 to adjust the amount of oil discharged. If adjusted, the protrusion 25 and the engagement groove 26 act as a rotation stopper, and it is possible to prevent the discharge amount from changing due to vibrations of the engine. In FIG. 1, 27 is a suction port, 28 is a discharge port, 29 is a seal, and 30 is a spring that biases the plunger 1 in the axial direction. FIG. 2 is a view taken in the direction of the arrows in FIG. 1, and the reference numerals in the figure indicate the same parts as in FIG.

FIGS. 3 and 4 are cross-sectional views taken in the direction of the - arrow in FIG. 1, and show that the discharge amount can be adjusted by rotating the rotation shaft 9. FIGS. That is, in FIG. 3, the distance between the protrusion 7 and the cam portion 8 is indicated by d, which is smaller than the height l of the lead cam 5 (FIG. 1), so only the discharge amount corresponding to the reciprocating length d can be obtained. However, as the rotation shaft 9 rotates, the distance between the protrusion 7 and the cam portion 8 becomes D as shown in FIG.
When the height of the plunger 1 is equal to or greater than l, the plunger 1 has a full stroke (reciprocating length)
The maximum discharge amount can be obtained.

[Operations and Effects] The plunger type oil pump of the present invention that manually adjusts the discharge amount has a rotating shaft 9 that adjusts the discharge amount.
Since it has the above-mentioned configuration, (1) Only one part is required.

(2) Low cost because it is molded from synthetic resin.

(3) By pushing the large diameter portion 21 of the rotating shaft 9 that adjusts the discharge amount into the shaft hole 19 from the shaft hole 18 side, it can be attached to the housing 14 with a snap action, reducing assembly man-hours. Reduced.

(4) To adjust the discharge amount, when the rotation shaft is rotated by a driver, the thin wall portion 2 having the protrusion 25
4 elastically retreats, disengages from the engagement groove 26, and elastically engages with another engagement groove 26, and furthermore, the protrusion 25 and the engagement groove 26 rotate reliably against engine vibrations. Has a stopping effect.

There is an advantage.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of a plunger type oil pump according to the present invention that manually adjusts the discharge amount, Fig. 2 is a view taken in the direction of the arrow in Fig. 1, and Figs. 3 and 4 are - from Fig. 1. Cross-sectional view, Figure 5 is from the Special Publication Publication Showa 46-24090.
FIG. 6 is a longitudinal sectional view showing the conventional structure of a plunger type oil pump whose discharge amount is manually adjusted. Explanation of symbols, 1... Plunger, 2... Worm gear, 3... Driving worm, 4... Cylinder, 5... Lead cam, 6... Guide pin section,
7...Protrusion, 8...Cam part, 9...Rotation shaft, 10
... Rotating lever, 11 ... Spring, 12 ...
Pin, 13...driver groove, 14...casing, 15
...Clip, 16,17...Axial neck, 18,1
9...Shaft hole, 20, 21...Large diameter part, 22, 23
... Sliding groove, 24 ... Thin wall part, 25 ... Protrusion, 2
6... Engagement groove, 27... Suction port, 28... Discharge port, 29... Seal, 30... Spring.

Claims (1)

[Scope of utility model registration request] A plunger 1 is disposed in a cylinder 4 in which an oil inlet 27 and an oil outlet 28 are open on the inner circumferential surface, and which opens and closes the inlet 27 and outlet 28 by rotational movement and performs a pumping action by reciprocating. A lead cam 5 is formed on the periphery of the end face of the plunger 1, and a protrusion 7 is formed on the center thereof; the lead cam 5 is brought into contact with the plunger 1 to give reciprocating motion to the plunger 1 in conjunction with the rotational movement of the plunger 1. A rotation shaft 9 formed integrally with a guide pin portion 6 and a cam portion 8 that abuts the projection 7 and limits the length of the reciprocating movement is perpendicular to the cylinder 4 and penetrates the pump housing 14. In a plunger type oil pump with a variable discharge amount, the discharge amount of oil can be adjusted by rotating the rotation shaft 9.
The rotation shaft 9 is made of a flexible synthetic resin material,
Shaft necks 16 and 17 that are rotatable in shaft holes 18 and 19 of the housing 14 are formed adjacent to the guide pin part 6 and the cam part 8, respectively. , 17 are formed adjacent to the outer end sides of the shaft necks 16, 17. Large diameter portions 20, 21 having a larger diameter than the diameters of the shaft necks 16, 17 are formed to engage with the outer end surfaces of the shaft holes 18, 19 to facilitate the rotation. The axial position of the shaft 9 is determined, and the large diameter portion 2
a sliding groove 22 passing through the center from the end face of one of the large diameter portions 21 to the center of the rotation shaft 9;
is provided to enable insertion of the large diameter portion 21 into the shaft hole 19, and a driver groove 1 is provided on the end surface of the other large diameter portion 20 for rotating the rotation shaft 9 with a driver.
3, and a sliding groove 23 extending from the end face toward the center of the rotation shaft 9 is eccentrically provided in the large diameter portion 20 to form a thin portion 24 including a small arc, and the outer periphery of the thin portion 24 is A protrusion 25 is provided on the arcuate surface of the pivot shaft 9, and the protrusion 25 elastically engages with one of the plurality of engagement grooves 26 formed in the housing 14 opposite to the protrusion 25. A plunger-type oil pump whose discharge volume can be manually adjusted and fixed at a desired angular position.