JPH0417818Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention has a plunger fitted into a pump cylinder with oil suction and oil discharge ports open.
By rotating around the center line of the plunger, the suction and discharge ports are opened and closed, and at the same time a reciprocating motion is performed, and the volume of the pumping chamber is changed to perform a pumping action, and the stroke length of the reciprocating motion is In an oil pump that changes the discharge amount of oil by limiting the stroke length of the reciprocating motion, the operation of moving the plunger in the direction of the center line in order to reduce the stroke length of the reciprocating motion is the period during which the suction and discharge ports are closed. This relates to an oil pump that operates with limited force even if it is inside.

Prior Art FIG. 3 is a sectional view of a conventional oil pump in which the pump action is performed by the rotational reciprocating motion of a plunger, and the discharge amount is varied by limiting the stroke length of the reciprocating motion. 1 is a pump housing, 2 is a driving worm, 3 is a plunger, 4 is a worm gear provided on the plunger 3 and meshes with the driving worm 2, and 5 is a worm gear formed around the end of the plunger, and 2 on the entire circumference. A lead cam consisting of two ridges, 6 a protrusion formed at the center of the end of the plunger 3, and 7 a cam shaft for controlling the discharge amount, which abuts against the lead cam 5 and rotates as the plunger 3 rotates. plunger 3
A guide pin portion 7- with a circular cross section that provides reciprocating motion to the
1, and a cam portion 7-2 that contacts the protrusion 6 to limit the stroke length of the reciprocating motion of the plunger 3 to control the discharge amount, and is controlled by a lever 7-3 fixed at one end. Rotated. Said plunger 3
A sub-plunger cylinder 8 is bored at the end opposite to the side where the lead cam 5 is formed, a sub-plunger 9 is disposed therein, and a pump action chamber 10 is formed. 11 is a disc 9- that engages the sub-plunger 9 with the sub-plunger 9;
1, the plunger 3 is pressed against the inner surface of the lid 1-1 disposed at the open end of the housing 1 on the other end side, and the lead cam 5 of the plunger 3 is pressed against the guide pin portion 7 of the cam shaft 7. -1 is a first spring that presses the other end side end surface of the plunger 3 in a direction to bring it into contact with the plunger 3. 12 is the plunger 3
is fitted into the pump cylinder, discharge ports 13 and 14 are open, and a through hole 15 is bored between the pump action chamber 10 and the outer peripheral surface of the plunger 3. FIG. 4 is a cross-sectional view taken in the direction of the - arrow in FIG.
As described above, 4 is a discharge port, 15 is a through hole connecting the pump action chamber 10 and the outer peripheral surface of the plunger 3, and 16 and 17 are suction ports opening into the pump cylinder 12. Although an actual oil pump has one suction port, two suction ports are provided in FIG. 4 to facilitate understanding of the pump action. When the driving worm 2 rotates, the plunger 3 is rotated within the cylinder 12 by the worm gear 4 that meshes with the driving worm 2, and the lead cam 5 is brought into contact with the guide pin portion 7-1 of the camshaft 7 by the action of the spring 9. Because of this, the plunger 3 reciprocates as it rotates. Therefore, when the through hole 15 and the suction port 16 or 17 overlap and the plunger 3 moves to the left in FIG. When the plunger 3 overlaps the discharge port 13 or 14 and the plunger 3 moves to the right in FIG. 3, the pump action chamber 10 contracts and oil is discharged. 5 and 6 are cross-sectional views taken in the direction of the - arrow in FIG. In the direction corresponding to the maximum discharge amount and minimum discharge amount, respectively,
This shows a state in which the top surface of the lead cam 5 is in contact with the guide pin portion 7-1 of the cam shaft 7, and the plunger 3 is at the right end of the reciprocating stroke in the figure. Then the fifth
In the case of the maximum discharge amount shown in the figure, since the distance d between the cam surface of the cam portion 7-2 and the protrusion 6 is greater than the height h of the peak of the lead cam 5, the reciprocating stroke of the plunger 3 is 2, it becomes equal to the height h of the ridge of the lead cam 5, and the discharge amount of the oil pump becomes maximum. In the case of the minimum discharge amount shown in FIG. 6, the distance d between the cam surface of the cam portion 7-2 and the end surface of the projection 6 is smaller than the height h of the lead cam 5, and the reciprocating stroke of the plunger 3 is d. Thus, by rotating the camshaft 7 using the lever 7-3, the discharge amount of the oil pump can be controlled as desired. In FIG. 7, 18 is a carburetor, 19 is an oil pump, and the throttle valve lever 18-1 of the carburetor 18 and the oil pump 1
If the lever 7-3 of 9 is connected with the cable 20, the discharge amount of the oil pump can be controlled in conjunction with the throttle valve lever 18-1. Note that the throttle valve lever 18-1 and the lever 7-3 of the oil pump 19 each independently move the spring 2 in the direction of the arrow 21.
2 and 23.

Problems with the Prior Art When the camshaft 7 is rotated to the maximum discharge amount position and the plunger 3 has finished its suction action, the camshaft 7 and the plunger 3 are in the relationship shown in FIG. 15 and intake ports 16, 17,
The relationship between the discharge ports 13 and 14 is as shown in FIG. 9, and the pump action chamber 10 is completely closed. In this state, when trying to move the camshaft 7 to a position where the discharge amount decreases, for example, to the minimum discharge amount position, that is, to the position where the camshaft 7 and the plunger 3 are in the relationship shown in FIG. 8 and 1, regardless of the rotational movement of the plunger 3.
In Figure 0, it must move in the right direction, that is, in the direction of reducing the volume of the pump action chamber 10, but as mentioned above, incompressible oil is confined within the pump action chamber 10. The plunger 3 cannot be moved, or if it is forced to move, an unreasonable force will be applied. The conventional method of operating the lever 7-3 of the oil pump was to link the lever 7-3 with a cable 20 as shown in FIG. 7, so the above-mentioned situation was dealt with by instantaneously loosening the cable 20. However, controlling the oil pump discharge amount in conjunction with the opening of the throttle valve of the carburetor is not sufficient; it is dependent on various engine operating conditions, such as engine temperature, rotational speed, acceleration, and intake air flow rate. It has become necessary to control the rotation of the camshaft using a control motor, such as a stepping motor, which is operated by an output signal from a control circuit that inputs and calculates lubricating oil temperature, etc. However, if the stepping motor and the camshaft 7 are directly connected, as described above, when the camshaft is rotated in a direction that reduces the discharge amount, an abnormally high torque is applied to the stepping motor, causing the stepping motor to step out of step. There is a problem.

means to solve problems The above problem is solved by the following configuration.

Structure of the invention: A pump cylinder that is bored in a pump housing and has an oil inlet and an oil outlet; a lead cam that fits into the pump cylinder and has a lead cam on the outer periphery of one end surface;
A projection is formed in the center, a sub-plunger cylinder is drilled concentrically from the end face on the other end side, and the inner end of the sub-plunger cylinder is connected to the suction and discharge ports opening to the pump cylinder. A through hole is opened in the radial direction and a worm gear is formed on the outer peripheral surface between the one end surface and the through hole opening, and the worm gear is reciprocated at the same time as the rotational movement within the pump cylinder. Plunger; rotatably disposed in the pump housing with its center line perpendicular to the center line of the pump cylinder, contacts the lead cam of the plunger, and gives reciprocating motion to the plunger as the plunger rotates; A guide pin portion having a circular cross section and a cam surface are formed which prevent the reciprocating motion by coming into contact with the protrusion of the plunger and change the stroke of the reciprocating motion by rotation to change the discharge amount of the oil pump. a cam shaft comprising a cam portion; a sub-plunger that fits into the sub-plunger cylinder of the plunger to form a pump action chamber; a cam shaft disposed at the open end of the pump housing on the other end side of the plunger; a first spring that presses the sub-plunger against the inner surface of the lid and also presses the other end side of the plunger in a direction that brings the lead cam of the plunger into contact with the guide pin portion of the camshaft; the pump housing; a driving worm disposed in the body and meshing with the worm gear of the plunger; rotation of the driving worm causes the plunger to rotate around the center line of the plunger, and the pump action chamber is connected to the suction port and the plunger; The pumping chamber is alternately electrically connected to the discharge port through the through hole, and the pumping action is performed by expanding and contracting the pumping chamber by reciprocating movement in the direction of the center line. In an oil pump in which the amount of oil discharged is adjusted by changing the reciprocating stroke of the plunger, instead of drilling the sub-plunger cylinder in the plunger, a hole with a diameter larger than the diameter of the sub-plunger is provided in the plunger. a cylindrical member that is concentrically bored in the hole and has an outer circumferential surface having the same diameter as the hole and an inner circumferential surface having the same diameter as the inner diameter of the sub-plunger cylinder; A sleeve having a flange that abuts the end face and limits the depth of insertion into the large diameter hole to a depth that does not close the through hole is slidably fitted, and the sub-plunger is fitted into the sleeve. the sub-plunger is slidably fitted into the sleeve, and the sub-plunger is disposed at the open end of the front housing concentrically with the first spring and inside the first spring; A second spring is disposed to press the inner surface of the lid body and bias the outer end surface of the sleeve in a direction to push the sleeve into the large diameter hole.

Embodiment FIG. 1 is a longitudinal sectional view showing an embodiment of the oil pump of the present invention, and the reference numerals shown in the figure are number 3.
In addition to indicating the same parts as the symbols shown in the figure,
1-1 is a lid disposed at the open end of the housing on the other end side of the plunger 3, and 8a is a cover body disposed at the open end of the housing on the other end side of the plunger 3; A large-diameter hole 24 is drilled to a diameter larger than that of the large-diameter hole 8a.
The sub-plunger cylinder 8 has an outer peripheral surface of the same diameter and an inner diameter of the sub-plunger cylinder 8.
A cylindrical member having an inner circumferential surface forming a cylindrical member, which is a cylindrical member having an inner circumferential surface that forms a cylindrical member, and is fitted into the large diameter hole to a depth that does not close the through hole 15 when it comes into contact with the end surface on the other end side of the plunger 3. This is a sleeve with a flange that is limited to . A second spring 25 is disposed between the sub-plunger 9 and the disc 9-1 that engages at the outer end of the sub-plunger 9, and the end surface of the sleeve 24, and is configured to rotate the disc 9-1. Through this, one end of the sub-plunger 9 is pressed against the lid 1-1, and as a reaction, the sleeve 24 is urged in the direction of being pushed into the large-diameter hole 8a.

Effect When the camshaft 7 is rotated from the angular position shown in FIG. 8 to the angular position shown in FIG. 10 with the pump action chamber 10 closed as shown in FIG. 9, the pump action chamber 10 is closed as described above. The oil trapped inside is compressed and the pressure increases, and the sleeve 24 is pushed to the right against the bias of the second spring 25, as shown in FIG. The plunger 3 can be moved from the position shown in Fig. 8 to the position shown in Fig. 10 without difficulty while maintaining the volume at the end, and the camshaft 7 can be moved to the 10th position within the step-out torque of the stepping motor. It can be rotated to the angular position shown in the figure. Thereafter, when the plunger 3 rotates and the through hole 15 overlaps the discharge port 13, the sleeve is pushed into the sub-plunger cylinder by the force of the spring 25 and returns to its normal position.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of an embodiment of the oil pump of the present invention, Fig. 2 is an explanatory view of the operation, Fig. 3 is a longitudinal cross-sectional view of a conventional oil pump, and Fig. 4 is a - of Fig. 3.
The sectional view, arrow direction view, Figures 5 and 6 are - of Figure 3.
This corresponds to a cross-sectional arrow view and is a diagram explaining discharge amount control by rotation of the camshaft. Figure 7 is a diagram showing an example of conventional use of an oil pump. Figures 8 and 10 are diagrams showing rotation of the camshaft. FIG. 9 is a diagram showing the state of the pump action chamber immediately after the plunger finishes its suction action. Explanation of symbols, 1...Pump housing, 2...Driving worm, 3...Plunger, 4...Worm gear, 5...Lead cam, 6...Protrusion, 7...
...Camshaft, 7-1...Guide pin section, 7-2...
Cam part, 7-3... Lever, 8... Sub-plunger cylinder, 9... Sub-plunger, 10...
Pump action chamber, 11... Spring, 12... Pump cylinder, 13, 14... Discharge port, 15...
Through hole, 16, 17... Suction port, 18... Vaporizer,
19... Oil pump, 20... Interlocking cable, 22, 23... Spring, 24... Sleeve, 25... Spring.

Claims (1)

[Scope of claim for utility model registration] An oil inlet 16 bored in the pump housing 1,
17 and discharge ports 13 and 14 are open; the pump cylinder 12 is fitted into the pump cylinder 12, and has a lead cam 5 formed on the outer periphery of one end surface and a protrusion 6 formed in the center, concentrically extending from the other end surface. A sub-plunger cylinder 8 is drilled at the inner end of the sub-plunger cylinder 8, and conduction is interrupted between this part and the suction ports 16, 17 and the discharge ports 13, 14 that open to the pump cylinder 12 as the sub-plunger cylinder 8 rotates. Through hole 1
5 opens in the radial direction, and the one end surface and the through hole 15
A plunger 3 having a worm gear 4 formed on its outer circumferential surface between the opening and the plunger 3, which rotates and reciprocates within the pump cylinder 12 at the same time; a guide pin portion 7-1 rotatably disposed on the body 1, abutting against the lead cam 5 of the plunger 3, and having a circular cross section to provide reciprocating motion to the plunger 3 as the plunger 3 rotates; A cam portion 7 is formed with a cam surface that comes into contact with the protrusion 6 of the plunger 3 to prevent the reciprocating movement of the plunger 3, and changes the reciprocating stroke by rotation to change the amount of oil discharged from the oil pump. −
2; a sub-plunger 9 that fits into the sub-plunger cylinder 8 of the plunger 3 to form a pump action chamber 10; a cam shaft 7 of the pump housing 1 on the other end side of the plunger 3; The sub-plunger 9 is pressed against the inner surface of the lid 1-1 disposed at the open end, and the lead cam 5 of the plunger 3 is pressed against the guide pin portion 7- of the camshaft 7.
a first spring 11 that presses the other end side end surface of the plunger 3 in a direction to bring it into contact with the plunger 1; a driving worm 2 that is disposed in the pump housing 1 and meshes with the worm gear 4 of the plunger 3; In addition, the driving worm 2
Due to the rotation of the plunger 3, the plunger 3 rotates around the center line of the plunger 3, and the pump action chamber 1 is rotated.
0 is alternately connected to the suction ports 16, 17 and the discharge ports 13, 14 through the through hole 15, and the pump action chamber 1 is reciprocated in the direction of the center line.
In an oil pump in which a pump action is performed by expanding or contracting 0, and the reciprocating stroke of the plunger 3 is changed by rotation of the camshaft 7 to adjust the amount of oil discharged, the plunger 3 Instead of drilling the sub-plunger cylinder 8, the sub-plunger 9
A hole 8a having a diameter larger than that of the sub-plunger cylinder 8 is concentrically bored in the plunger 3, and the hole has an outer peripheral surface having the same diameter as the hole and an inner peripheral surface having the same diameter as the inner diameter of the sub-plunger cylinder 8. A cylindrical member, the plunger 3
A sleeve 24 is slidably fitted into the sleeve 24, which has a flange that abuts against the end surface of the other end and limits the depth of insertion into the large diameter hole 8a to a depth that does not close the through hole 15. , the sub-plunger 9 is slidably fitted into the sleeve 24, and the first spring 1
1, the sub-plunger 9 is pressed inside the first spring 11 against the inner surface of the lid 1-1 disposed at the open end of the housing 1, and the sleeve 24 is inserted into the large diameter hole. A second spring 25 is arranged to bias the outer end surface of the sleeve 24 in the pushing direction, and the through hole 15 is not electrically connected to either the suction ports 16, 17 or the discharge ports 13, 14. Under the cam part 7-
When the camshaft 7 rotates in a direction in which the cam surface of the second spring contracts the pump action chamber 10, the sleeve 24 resists the bias of the second spring 25 due to the increase in oil pressure within the pump action chamber 10. large diameter hole 8a
An oil pump characterized in that it can move in a direction to escape from the pump chamber 10 to prevent an abnormal pressure rise in the pump action chamber 10.