JPS6316872Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an oil pump used in engines and the like to supply oil for control and lubrication.

In conventional plunger-type oil pumps, oil is supplied by the reciprocating motion of a plunger driven via a push rod by a cam rotated by power from an engine, etc. In a conventional plunger-type oil pump, the plunger is moved by the lift of the cam. When pushed back by the return spring, the push rod and plunger are separated and then come into contact with each other again, causing a problem in which noise is generated.

In order to solve this problem, the present applicant proposed in Utility Model Application No. 56-166,524 (Japanese Utility Model Publication No. 58-72469) that the plunger 6 and the substantially cylindrical An oil pump has been proposed in which a coil spring 12' is provided between the plunger 6 and the push rod 11' to prevent the plunger 6 and the push rod 11' from coming into contact with each other. In FIG. 2, 3 is an inlet passage, 4 is an outlet passage, 5 is a housing, 9 is a return spring, and 13 is a shaft that is rotated by power from an engine or the like and forms a cam 14.

In such an oil pump, the discharge amount of oil supplied by one reciprocating movement of the plunger 6 is the same as that of the plunger 6 when there is no lift.
From the volume of the pump chamber surrounded by the bottom wall of the plunger, the bottom wall of the plunger at maximum lift, and the inner surface of the housing 5,
The volume is calculated by subtracting the volume of the portion of the push rod 11' that protrudes into the pump chamber during lift. In other words, the combined volume of the cylindrical portion of the push rod 11' projecting into the pump chamber and the oil filled inside thereof constitutes the dead space of the pump chamber.

By the way, in the conventional oil pump described above, one end of the coil spring 12' is disposed inside the cylindrical push rod 11'.
The outer diameter of the push rod was larger than the outer diameter of the coil spring, and there was a limit to how small the push rod's outer diameter could be made. For this reason, the dead space cannot be made small, and it is necessary to increase the volume of the pump chamber in order to obtain the desired oil discharge amount, resulting in a problem that the pump becomes larger.

The present invention has been proposed in view of the above, and is an oil pump that supplies oil through reciprocating motion of a plunger driven by a cam via a push rod, in which a recess is provided in the bottom wall of the plunger. The oil pump is characterized in that one end of a coil spring is disposed in the recessed portion, and a spring guide portion inserted into the inside of the other end of the coil spring is provided at the tip of the push rod. .

According to the above configuration, the coil spring acts as a buffer material to prevent the plunger and the push rod from colliding with each other, thereby preventing the generation of noise, and the diameter of the push rod can be reduced, so the oil pump can be made more compact. It is.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIG.

In FIG. 1, the oil pump includes a housing 5 having a coaxial large-diameter hole 1 and a small-diameter hole 2, an inlet passage 3 communicating with both holes, and an outlet passage 4 communicating with both holes.
The plunger 6 is slidably fitted into the large diameter hole 1, and the retainer 7 is interposed between the bottom wall of the plunger and the retainer 7 to press the plunger downward in FIG. A return spring 9 held against a snap spring 8 fixed to the housing 5, and a guide member 1 fitted into the small diameter hole 2.
The push rod 1 consists of a push rod 11 that slides inside the plunger 6, and a coil spring 12 interposed between the push rod and the plunger 6.
1 is pressed downward in FIG. 1 by the interaction between the return spring 9 and the coil spring 12, and comes into contact with a cam 14 formed on a shaft 13 that is rotationally driven by, for example, power from an engine.

The coil spring 12 has a spring constant greater than that of the return spring 9, and its spring constant and free length are set so that the plunger 6 and push rod 11 do not collide under any operating conditions.

A coil spring 1 is attached to the bottom wall of the plunger 6.
A recess 15 is provided which is slightly larger than the outer diameter of 2 and receives one end of the recess. Further, a spring guide portion 16 is provided at the tip of the push rod 11. The spring guide portion 16 has a diameter slightly smaller than the inner diameter of the coil spring 12, is inserted into the spring, and has its other end mounted thereon.

In the oil pump according to the present invention having the above-described structure, the coil spring 12 is provided between the plunger 6 and the push rod 11 to act as a buffer material, so that the cam 14 is not lifted when the cam 14 is lifted. It is possible to prevent the plunger 6 and the push rod 11 from colliding with each other in both the state where the lift of the cam 14 is maximum and the state where no lift occurs from the maximum lift state as shown in FIG. This can prevent the generation of noise.

Furthermore, a recess 15 is provided in the bottom wall of the plunger 6, and a spring guide part 16 is provided at the tip of the push rod 11, and the coil spring 12 is supported between the recess and the spring guide part. Compared to the case where one end of the coil spring is placed, the push rod 11
Therefore, the dead space of the pump chamber is reduced, the volume of the pump chamber necessary to obtain a desired oil discharge amount can be reduced, and the oil pump can be made more compact. In particular, the oil pump is equipped with a cylinder deactivation system that uses a valve stop device operated by hydraulic pressure from the oil pump to stop operation of the intake and exhaust valves of some cylinders and deactivate the cylinders depending on the operating state. When used in a cylinder engine and when the cam for driving the oil pump is installed at the rear end of the engine's camshaft, an oil pump with one end of the coil spring placed inside the push rod has a limited space at the rear end of the cylinder head. Although it is difficult to install it within a certain space, and there are also problems with the workability and durability of the push rod, the use of the compact oil pump of the present invention is extremely beneficial as it can solve these problems. .

[Brief explanation of the drawing]

Figure 1 is a sectional view of the oil pump according to the present invention.
FIG. 2 is a sectional view of a conventional oil pump. 5...Housing, 6...Plunger, 9...
Return spring, 11... Push rod, 12
... Coil spring, 13 ... Shaft, 14 ... Cam, 15 ... Recess, 16 ... Spring guide part.

Claims (1)

[Scope of utility model registration request] In an oil pump that supplies oil by the reciprocating motion of a plunger driven by a cam via a push rod, a recess is provided in the bottom wall of the plunger, one end of a coil spring is disposed in the recess, and the coil An oil pump characterized in that a spring guide portion inserted inside the other end of the spring is provided at the tip of the push rod.