JPS5930212Y2 - Fuel pump drive mechanism - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a drive mechanism for a membrane fuel pump.

The drive mechanism of conventional membrane fuel pumps has a
There are some as shown in Fig. 2 and Fig. 2.

The mechanism shown in Fig. 1 is of a type in which a fuel pump (hereinafter referred to as pump) A is arranged in the lateral direction of camshaft 1, and one end side of pump lever (hereinafter referred to as lever) 3 is connected to cam 2 of camshaft 1. By making the bong 7W5 swing freely around the fulcrum 4 in abutting relation and by connecting the other end to the membrane rod 6 of the pump membrane 5, the bong 7W5 can be swung in the vertical direction in the figure in relation to the rotation of the cam 20. When the pump membrane 5 is pushed down to the lower position, fuel is sucked into the pump chamber 9 through the inflow lower and the suction valve 8, and the pump membrane 5 is pushed up by the biasing force of the membrane spring 10 and lever spring 11. At this time, the fuel in the pump chamber 9 is compressed and sent from the delivery valve 12 through the supply hole 13 to the float chamber (not shown) of the carburetor.

However, with modern engines equipped with many exhaust gas countermeasure devices and parts, the above configuration in which the pump A is placed laterally of the camshaft 1 may also require the placement of exhaust gas control components that become hot near the pump. However, it requires a lot of installation space, and its arrangement and arrangement are complicated, making it unsuitable for small cars where space in the engine room is restricted, and is also an obstacle to downsizing.

On the other hand, the mechanism shown in Figure 2 compensates for the above drawbacks.
This is a type in which the pump A is placed on an extension of the camshaft 1.

This type has camshaft 1 at the end of camshaft 1.
A gear (distributor drive gear) 15 having a tapered cam surface 14 that intersects with the outer casing 1 is attached.
A bushing rod 17 parallel to the camshaft 1 is fitted into the bushing rod 6 so as to be slidable in the axial direction, one end of the bushing rod 17 is brought into contact with the cam surface 14, and the other end is brought into contact with the lever 3 of the pump A. .

Therefore, the bushing rod 17 is always pressed toward the cam surface 14 by the lever 11 via the lever 3.

When the camshaft 1 rotates, the cam surface 14 of the gear 15 is displaced in the axial direction with respect to the bushing rod 17, and the bushing rod 17 moves in the axial direction following the cam surface 14, causing the lever 3 to swing.

The operation of the pump A by the lever 3 is the same as in the case of FIG. 1 above.

However, in the case of this type, the relatively long bushing rod 17 and the pump A are arranged in the axial direction of the camshaft 1, so the overall axial length becomes long, which also makes installation difficult. These restrictions are an obstacle to compactness.

Therefore, in view of the above-mentioned shortcomings of the conventional fuel pump drive mechanism, this invention has been developed to improve the drive mechanism, improve mountability on small vehicles by shortening the dimensions, prevent omission of bushing rod assembly, and improve reliability. We will try to provide you with what you deserve.

The configuration of the present invention will be explained below according to embodiments shown in the drawings.

It should be noted that the same reference numerals as in the prior art represent the same members.

As shown in FIG. 3, the drive mechanism of the present invention belongs to a type in which the fuel pump A is arranged on an extension line of the camshaft 1, and a ball 18 is fitted as a spherical contact body into the tip of the fuel pump prepper 3. The ball 18 is brought into contact with the end cam surface of the camshaft 1, in this embodiment, the stem-shaped cam surface 14 of the gear 15.

In this case, the driving force of the pump A is such that the cam surface 14 is displaced in the axial direction with respect to the ball 18 due to the rotation of the camshaft 1,
Following this, the ball 18 moves in the axial direction and the lever 3
It is obtained by shaking the .

Therefore, according to the present invention, the axial dimension can be significantly shortened compared to the case where the bush rod 17 is used.
Easy to install on small vehicles.

Further, the assembly can be done by fitting the ball 18 into the lever 3 in advance, and there is no need to assemble the push rod 1 and 0 in a separate process as in the conventional case.

Furthermore, since the lever 3 and the ball 18 are integrally constructed, and the ball 18 directly contacts the cam surface 14 to transmit driving force, the operation of the pump A is reliable and reliability is improved.

It is better to fit the spherical contact body into the lever in a rotatable state, and other shapes are shown in Fig. 4a.

This is shown in b.

[Brief explanation of drawings]

FIGS. 1 and 2 are longitudinal sectional views showing a conventional fuel pump drive mechanism, FIG. 3 is a longitudinal sectional view of the same mechanism according to the present invention, and FIGS. 4 a and 4 b are views of other spherical contact bodies. It is an example figure. 1...Camshaft, 3...Pump lever 5...Pump membrane, 14...Taber-shaped cam surface, 15... Gear, 1B...
...Ball, A...Fuel pump.

Claims (1)

[Scope of utility model registration request] In this type of fuel pump, the pump lever swings in contact with the cam of the camshaft, activating the pump membrane to suck in and send out fuel.The fuel pump is placed in a position where the camshaft is extended, and A drive mechanism for a fuel pump, characterized in that a tapered cam surface is formed on the pump lever, a spherical contact body is fitted into the tip of the pump lever, and the ball is brought into contact with the cam surface.