JPS6316805Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a lubricating oil pump for a two-stroke engine.

In a so-called separate oil supply system in which fuel and lubricating oil are separately supplied in a two-cycle engine, a lubricating oil pump is required to supply the amount of oil in accordance with the engine speed and output. When the engine is in a low speed range such as when the engine is idling, the amount of oil supplied to the engine can be as small as 1 c.c. per hour. Exhaust gas contains a large amount of white smoke, causing a white smoke problem. Furthermore, if a smaller amount of oil is supplied than the specified amount, the lubricity of the engine will deteriorate, causing so-called engine friction, which will lead to engine damage.

For these reasons, the lubricating oil pump for a two-stroke engine is required to accurately control the discharge amount, and conventionally, a lubricating oil pump as shown in FIG. 1 has been used.

A feature of this lubricating oil pump is that the passage of the suction passage to the distributor is switched by a disc valve, and according to this, a hole is bored on the outer peripheral side of the distributor. This has the advantage of improving machining accuracy and reducing the difficulty of machining because the number of facilities is reduced.

Hereinafter, a specific example of a conventional lubricating oil pump will be explained with reference to FIG.

1 is a pump body having a shaft hole 1A bored in its lower part and a cylinder hole 1B in its upper part; 2 is a cam body rotated by a worm gear 3 which rotates synchronously with the rotation of the engine; . A cam surface 2A is formed on the lower end surface of the cam body 2, and a flat surface 2B is formed on the upper end surface.
A shaft 4 is drilled from the center onto the flat surface 2B.

Reference numeral 5 designates a cylindrical distributor rotatably disposed in the cylinder hole 2A of the pump body 1, the center of which is supported by the shaft 4, and the lower end surface 5A of the distributor 5 is a cam. It is placed on the flat surface 2B of the body 2 with a gap S therebetween.
(The formation of the gap S will be described later.) Further, a cylinder hole 5A having a small diameter is bored upward from the lower end surface 5B of the distributor 5, and the end thereof is inserted into the cylinder hole 5A. A plunger 7 engaged with the flat surface 2B of the body 2 is slidably disposed, and a pump chamber 8 is formed by the cylinder hole 5A and the plunger 7. Further, a discharge hole 8A opens from the pump chamber 8 toward the outer side of the distributor 5, and a suction hole 8B opens toward the upper end flat portion 5C.

A discharge valve seat 10 connected to the discharge passage 9 is provided in the pump body 1 at a position corresponding to the discharge hole 8A.
On the other hand, a suction valve seat 1 corresponding to the suction hole 8B is provided on the upper end flat portion 5C of the distributor 5.
A flat disk valve 12 having a hole 1 is disposed therein. The center of this disc valve 12 is guided by the shaft 4 and is connected to the protrusion 1A of the pump body 1.
Rotation is prevented by. Therefore, the lower surface of the disc valve 12 is on the upper end flat portion 5C of the distributor 5, and the upper surface of the disc valve 12 is opposed to the upper surface 1C of the cylinder hole 1B of the pump body 1.

The disc valve 12 and the suction valve seat 11 are connected to a suction passage 13 provided in the upper part of the pump body 1. Reference numeral 14 designates a plunger spring that is contracted in the pump chamber 8 and constantly presses the plunger 7 against the flat surface 2B of the cam body 2. A gap is formed between the lower end surface 5B of the motor 5 and the flat surface 2B of the cam body 2.

In addition, 6 is a connecting shaft fitted into the cam body 2 and the distributor 5 in order to rotate the cam body 2 and the distributor 5 integrally, and 15 is the shaft hole 1.
The cam surface 2 of the cam body 2 is rotatably supported in A.
This is the discharge amount control shaft that is locked to A. In such a lubricating oil pump, when the engine rotates and the worm gear 3 rotates, the cam body 2 rotates due to this rotational force, and the cam surface 2A rotates on the discharge amount control shaft 15, so that the cam body 2 The cam surface 2A performs vertical reciprocating motion and rotation according to the cam stroke. According to the rotation of the cam body 2, the distributor 5 also rotates synchronously by the connecting shaft 6, and the discharge hole 8A and the suction hole 8B are connected to the suction valve seat 11 and the discharge valve seat 10.
This is to switch between the two.

On the other hand, according to the vertical reciprocating motion of the cam body 2, the plunger 7 is constantly pressed against the flat surface 2B of the cam body 2 by the plunger spring 8, so the plunger 7 reciprocates vertically within the cylinder hole 5A. .

Then, during the downward stroke of the plunger 7, the suction hole 8B and the suction valve seat 11 are opened, and the discharge hole 8B is opened.
By closing A and the discharge valve seat 10, oil is sucked into the pump chamber 8 from the suction passage 13, and then, during the upward stroke of the plunger 7, the discharge hole 8A and the discharge valve seat 10 are opened and the oil is sucked. By closing the hole 8B and the suction valve seat 11, the oil in the pump chamber 8 is discharged to the discharge passage 9.

A lubricating oil pump that performs such an action has the disadvantage that the discharge amount cannot be accurately controlled. This is due to variations in the suction amount during the suction process of the pump chamber 8 into the cylinder hole 5A through the suction passage 13, suction valve seat 11, and suction hole 8B. This is because the upper end flat portion 5C may not be in complete contact with the lower surface of the disc valve 12.

That is, the upper surface of the disc valve 12 is the pump body 1.
This occurs especially when the upper surface 1C of the cylinder hole 1B is not flat in the direction perpendicular to the cylinder hole 5A because the cylinder hole 1B is pressed by the upper surface 1C.

In order to accurately maintain the flatness of the upper surface 1C of the cylinder hole 1B in the direction perpendicular to the cylinder hole 5A, a highly accurate machine, expensive cutting tools, and long machining time are required, which significantly increases the product cost. It is something.

The purpose of the lubricating oil pump of the present invention is to provide a lubricating oil pump using such a conventional disc valve that can accurately maintain the discharge amount and is inexpensive. do.

It should be noted that components having the same functions as those of the prior art will be designated by the same reference numerals and descriptions will be omitted.

Disc valve 12 and disc distributor 5
In order to ensure a good and reliable connection with the cylinder hole 1B, a sufficient gap H is provided so that the upper surface 1C of the cylinder hole 1B does not touch the upper surface of the disc valve 12, and a spring is provided between the upper surface of the disc valve 12 and the pump body 1. 16 is compressed, and the lower surface of the disc valve 12 is forcibly pressed against the upper surface of the distributor 5 by the spring force of the spring 16. In this way, the disc valve 12
The plunger 7 can be reliably connected to the distributor 5 by the spring 16.
Leakage from the joint surface during the discharge stroke is eliminated, and the disc valve 12 is no longer lifted from the upper surface of the distributor 5 due to rising pressure during the discharge stroke, allowing accurate control of the amount of discharged oil. be.

In addition, wear due to friction during use is only at the contact surface between the disc valve and the disc distributor, and even if that contact surface wears out, the spring 16
Since the contact surface is constantly pressed, there is no possibility of leakage from the contact surface.

As described above, according to the lubricating oil pump of the present invention, the disk valve is pressed against the upper end surface of the disk distributor using an elastic member such as a spring, so that the connection between the disk valve and the disk distributor is good. Furthermore, since the disc valve does not float up, the amount of discharged oil can be accurately controlled, making it effective as a lubricating oil pump for two-stroke engines.

In addition, the manufacturing process requires only flat processing of one side surface to the joint surface of the disc valve and the upper end surface of the disk distributor, and the processing can be carried out extremely easily by surface polishing, rapping, etc.

[Brief explanation of drawings]

Figure 1 is a vertical sectional view showing a conventional lubricating oil pump.
FIG. 2 is a longitudinal sectional view showing an embodiment of a lubricating oil pump for a two-stroke engine according to the present invention. 5...distributor, 11...intake valve seat, 12...disk valve, 16...spring.

Claims (1)

[Claims for Utility Model Registration] A cam body 2 that is driven by the rotation of an engine and has a cam surface 2A at its end; a cylinder 5A, and a plunger 7 that reciprocates by the cam body 2. A pump rotating in synchronization with the cam body 2 includes a pump chamber 8 formed therein, a suction hole 8B that opens from the pump chamber toward its upper end, and a discharge hole 8A that opens toward its outer side. A discharge valve seat 10 corresponding to the discharge hole 8A and connected to the discharge passage 9, and a suction passage B corresponding to the suction hole 8B.
A lubricating oil pump has a suction valve seat 11 connected to A lubricating oil pump for a two-stroke engine, which is made up of an elastic member that presses against the upper end surface of the distributor 5.