JPS5842588Y2 - How do you get started? - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an injection timing adjustment device for a fuel injection pump in which the injection timing can be changed by moving the support position of the tappet and changing the relative position with respect to the cam.

A conventional fuel injection pump is constructed by fitting a tappet interposed between a cam and a plunger into a pump body so as to be slidable in the same axial direction as the plunger.

In this case, in order to change the injection timing, a notch is provided at the top of the plunger, or an auto-timer is provided that can change the relative angle of the plunger with respect to the cam.

Therefore, in the former case, the plunger must be provided with a notch that is difficult to machine, and precision is required.

Moreover, the latter has the disadvantage that the structure of the auto-timer is complicated and the cost is extremely high.

Furthermore, there are devices known in Utility Model Publication No. 13608/1980, Utility Model Application Publication No. 6304 of 1942, and Japanese Patent No. 42888 as a speed governor that changes the relative position between the tappet and the cam. All of these types use the eccentric rotation of an eccentric shaft installed on a shaft located on the side of the cam to change the relative position between the tappet and the cam, so the radius from the center of rotation of the eccentric shaft is The distance from the axis of the tappet coupling pin eccentrically arranged in the direction is smaller than the distance from the axis to the rotation axis of the tappet roller.

Therefore, in order to move the tappet of these known devices forward and backward relative to the cam, it is necessary to increase the eccentricity of the tappet coupling pin attached to the eccentric shaft. The size cannot be made sufficiently large because it would become too large.

In addition, in such known devices, the rotational force transmission mechanism from the governor to perform eccentric rotation of the eccentric shaft requires an excessively large member in the direction of the camshaft, or requires complicated components such as gears. Since many structural members are required and there are many locations where mechanical loss occurs, if a speed governor is used, a large one is required and there is a problem in that good advance characteristics of the internal combustion engine cannot be obtained.

The present invention aims to improve the above-mentioned conventional drawbacks, and to explain the drawings showing an embodiment, a roller 4 is provided between a plunger 2 fitted in a pump body 1 and a cam 3. A tappet 5 is provided.

This tappet 5 has a pin 9 on the other end side of a speed governor lever 8 whose one end side is rotatably supported by a support pin 7 through a connecting rod 6.
10 and perpendicular to the cam shaft center (horizontal direction of the arrow)
It is freely movable, and can freely swing up and down using the pin 9 as a fulcrum.

The governor lever 6 has a governor spring 11 made of bamboo, and a protrusion 8' formed on the side of the support pin 7 engages with the governor shaft 12.

13 is an adjustment rod fixed to the plunger 2, and 14 is a plunger spring.

In addition, a governor hose is placed at an appropriate position on the governor lever 8 so as to move the tappet 5 to the lateral (G) side in the rotational plane of the cam 3 in response to an increase in the rotational speed of the engine. The axial force generated at the speed governor lever 8 is applied to the speed governor lever 8.

When the rotational speed of the engine increases with the above configuration, the governor shaft 12 moves to the outside in the axial direction due to the operation of the governor,
Furthermore, the end portion of the speed governor shaft 12 rotates the speed governor lever 8 around the center of the support pin 7 and, via the connecting rod 6,
The tappet 5 is moved in the (G) direction, and at the same time the regulating spring is expanded.

As a result, the roller 4 moves away from the axis of the plunger 2 toward the lateral (G) side in the rotational plane of the cam 3, and the cam 3 pushes up the plunger 2 via the tappet 5. The time to start is earlier.

Also, when the engine speed decreases, the opposite effect to the above occurs,
That is, the governor shaft 12 moves inward in the axial direction, and in order to follow this, the governor lever 8 is rotated around the center of the support pin 7 by the compression force of the governor spring 11, and the connecting rod 6 is rotated.
Move the tappet 5 in the direction of (→).

As a result, the roller 4 moves toward the lateral direction ←10 in the rotational plane of the cam 3 relative to the axes of the plunger and plunger 2, and the cam 3 pushes up the plunger 2 via the tappet 5. It's too late to start.

In summary, the present invention includes a tappet 5 between the fuel cam 3 and the plunger 2, which is provided with a roller 4 that rolls on the fuel cam 3 and whose upper surface is slidably in contact with the lower end side of the plunger 2. The tappet 5 and the speed governor lever 8 rotatably supported on the pin 7 are interlocked and connected via the pin 10, and at this time, the axial distance between the pin 10 and the support pin 7 is set to the pin 10. is larger than the distance between the axes of the roller 4, and the governor hose is placed in the appropriate position of the governor lever 8 so as to move the tappet 5 to (-[!l) in response to an increase in the engine rotational speed. Since this is an injection timing adjustment device for a fuel injection pump characterized in that it is configured to act on the lever 8, it has the following effects.

■ By moving the tappet away from the plunger axis in the lateral direction within the rotational plane of the cam, it is possible to change the timing at which the cam starts pushing up the plunger via the tappet, making it difficult to machine the plunger. There is no need to provide a notch for starting the plunger pressure application process, and the precision machining inside the pump is reduced, resulting in a simple and inexpensive pump device.

■ Since the amount of lateral movement of the tappet can be increased appropriately according to the size of the cam, the range of injection timing adjustment is wider than that using conventional plunger notches, and injection timing adjustment is made that much more efficient. It can be performed easily and accurately.

■ The governor hose that acts on the tappet has no mechanical loss caused by gears or many bearings, compared to the conventional slanted type, so the transmission is more efficient, which improves the advance characteristics of the internal combustion engine. In addition, the entire device can be made compact.

■ Pin σ that interlocks and connects the governor lever and tappet)
Since the vertical movement accompanying the arc rotation around the support pin is small, the tilting range of the tappet is also reduced, and many practical effects such as the ability to simplify the shape of the tappet can be obtained.

[Brief explanation of drawings]

The drawing is a longitudinal sectional side view of the device of the present invention. 2...Plunger, 3...Cam, 4...Roller 5...Tappet, 8...Governor lever, 9...
Pin 12... Governor axis, 15... Adjustment axis, 16...
··pin.

Claims (1)

[Scope of utility model registration request] A tappet 5 is interposed between the fuel cam 3 and the plunger 2, and the tappet 5 includes a roller 4 that rolls on the fuel cam 3 and whose upper surface is in slidable contact with the lower end of the plunger 2. A speed governor lever 8 rotatably supported on a support pin 7 is interlocked and connected via a pin 10.
0 and the distance between the axes of the support pin 7 and the pin 10 and the roller 4.
The cabana hose is configured to act on the governor lever 8 so as to move the tappet 5 toward the (field side) in response to an increase in the rotational speed of the engine. An injection timing adjustment device for a fuel injection pump, characterized in that: