JPH0544634A - Driving device for fuel feed pump of engine - Google Patents

Abstract

PURPOSE:To maintain the engine start performance high and shorten the air vent time for a fuel feed pump by permitting a pump driving cam to be slidingly selected between a locker arm interlocking state and a locker arm release state. CONSTITUTION:A pump driving cam 3 is slidingly selected between a locker arm movement state where the input edge part 9 of a locker arm 4 is attached onto a cam surface 8 and a locker arm release state where an input edge part 9 is separated from the cam surface 8. Accordingly, during the engine start, if the cam 3 is selected to the locker arm release state, the input edge part 9 of the locker arm 4 can be demounted from the cam stop position 12 of the cam 3, and the swing range of the locker arm 4 can be maintained always in a high pump efficiency range when a fuel feed pump 5 is operated by a manual operating lever 7. Accordingly, the engine start performance can be maintain always high, and the air vent operation for the fuel feed pump 5 can be carried out in a short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for an engine fuel supply pump.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional technique of a drive device for a fuel supply pump of an engine. This is because the pump drive cam 10 is connected to the cam shaft 101 that is linked to the crank shaft.
3, the fuel supply pump 105 is interlockingly connected to the pump drive cam 103 via the rocker arm 104,
The rocker arm 104 is interlockingly connected to the manual operation lever 107.

According to this structure, at the time of engine starting, the fuel supply pump 105 is manually interlocked with the manual operation lever 107 through the rocker arm 104 to sufficiently inject fuel into the intake path, thereby improving startability. Can be increased. Further, it is possible to release air from the fuel supply pump 105. By the way, in this prior art, there is no means for removing the input end 109 of the rocker arm 104 from the cam surface 108 of the pump drive cam 103.

[0004]

SUMMARY OF THE INVENTION Pump driving cam 103
The rocking range of the rocker arm 104 is usually set to the range having the highest pump efficiency. However, in the above-described conventional technique, there is no means for removing the input end 109 of the rocker arm 104 from the cam surface 108 of the pump drive cam 103. So
The input end 109 of the rocker arm 104 while the engine is stopped
Is stopped at the cam top position 110 of the pump drive cam 103, the rocking range of the rocker arm 104 is out of the range of high pump efficiency when the fuel supply pump 105 is operated by the manual operation lever 107. Therefore, in this case, the startability of the engine is lowered, and it takes time to bleed the fuel supply pump 105.

An object of the present invention is to allow the input end of the rocker arm to be removed from the cam top position of the pump drive cam while the engine is stopped.

[0006]

According to the present invention, as illustrated in FIG. 1A, a pump drive cam 3 is attached to a cam shaft 1 which is interlocked with a crank shaft, and a rocker arm 4 is attached to the pump drive cam 3. A fuel supply pump drive device for an engine, which is configured by interlockingly connecting a fuel supply pump 5 and interlockingly connecting the rocker arm 4 to a manual operation lever 7, is characterized by the following.

That is, as illustrated in FIG. 1 (B),
A rocker arm interlocking posture 10 in which the pump drive cam 3 is slidably fitted to the cam shaft 1 and the input end 9 of the rocker arm 4 is brought into contact with the cam surface 8 of the pump drive cam 3, As illustrated in (C), it is characterized in that the slide can be switched to the rocker arm releasing posture 11 for separating the input end 9 of the rocker arm 4 from the cam surface 8.

[0008]

The operation and effect of the present invention: The pump drive cam 3 is slidably fitted to the cam shaft 1, and the pump drive cam 3 is brought into contact with the input end 9 of the rocker arm 4 on the cam surface 8 thereof. 10 and the rocker arm releasing posture 11 for disengaging the input end 9 of the rocker arm 4 from the cam surface 8 of the rocker arm 4 are possible to slide. Therefore, when the pump drive cam 3 is switched to the rocker arm releasing posture 11 while the engine is stopped, The input end portion 9 of the rocker arm 4 can be removed from the cam top position 12 of the pump drive cam 3, and when the fuel supply pump 5 is operated by the manual operation lever 7, the rocking range of the rocker arm 4 is always kept at the pump efficiency. It can be maintained in a high range. For this reason, the engine startability can always be kept high, and the fuel supply pump 5 can be deaerated in a short time.

[0009]

Embodiments of the present invention will be described with reference to the drawings.
1A and 1B are views for explaining a drive device of a fuel supply pump for an engine according to an embodiment of the present invention. FIG. 1A is a vertical cross-sectional view of the drive device, and FIG. 1B is B of FIG. 1A. -Explanatory view of the rocker arm interlocking posture of the pump drive cam in the B line cross section, FIG.
(C) is an explanatory view of a rocker arm releasing posture of the pump drive cam.

In FIG. 1, reference numeral 1 indicates a cam shaft, which is interlockingly connected to a crank shaft (not shown). As shown in FIG. 1A, the cam shaft 1 is projected into the cam chamber 2 of the engine, and the pump drive cam 3 is attached to the cam shaft 1. A fuel supply pump 5 is provided outside the cam chamber 2.
Is attached.

The fuel supply pump 5 is as follows. A diaphragm 14 is provided below the pump chamber 13,
A pump input shaft 15 is vertically installed from the diaphragm 14,
A disc-shaped pump input unit 6 is attached to the lower end of the pump input shaft 15. The diaphragm 14 is biased upward by the diaphragm spring 17. Fuel is sucked into the pump chamber 13 by the lowering of the diaphragm 14, and
Fuel is discharged from the pump chamber 13 as the diaphragm 14 rises.

A rocker arm 4 is erected from inside the pump case 18 to inside the cam chamber 2, and the rocker arm 4 is swingably supported by a pivot shaft 19 provided inside the pump case 18. The input end 9 of the rocker arm 4 is brought into contact with the cam surface 8 of the pump drive cam 3 from above, and the output end 20 of the rocker arm 4 is brought into contact with the pump input portion 6 from above. This rocker arm 4
Is urged by the rocker arm spring 21, and the input end 9
Is pressed against the cam surface 8. When the input end 9 of the rocker arm 4 is pushed up by the cam surface 8 of the pump drive cam 3, the rocker arm 4 swings to move the diaphragm 14 through the pump input shaft 15 and the diaphragm spring 17.
Will fall against the urging force of.

A rotary shaft is passed through the lateral wall of the pump case 18, and a manual operation lever 7 is attached to the outer end of the rotary shaft. A semi-circular cam 23 is provided at the inner end of the rotary shaft, and a lower corner portion 24 of the semi-circular cam 23 faces a pressure receiving portion 25 that is vertically provided from the rocker arm 4. When the manual operation lever 7 is pushed down, the pressure receiving portion 25 is pushed by the lower corner portion 24 of the semicircular cam 23, and the rocker arm 4 swings to move the diaphragm 14 through the pump input shaft 15 and the diaphragm spring 17.
Will fall against the urging force of.

In this fuel supply pump drive device, the following measures are taken so that the input end 9 of the rocker arm 4 can be removed from the cam top position 12 of the pump drive cam 3 while the engine is stopped. As shown in FIG. 1 (B), the pump drive cam 3 is configured by extending a small diameter portion 27 having the same diameter as the basic circle of the cam surface 8 on the side of the cam body 26 having the cam surface 8. The cam surface 8 of the cam body 26 and the peripheral surface 28 of the small diameter portion 27 are connected by an inclined guide surface 29. The pump drive cam 3 is spline-fitted to the cam shaft 1 so that it can be slid along the axial direction of the cam shaft 1. The cam body 26 of the pump drive cam 3 is the cam shaft 1
The small diameter portion 27 is located on the side closer to the base end of the cam shaft 1 and on the side closer to the tip of the cam shaft 1.

Further, as shown in FIG. 1B, the cam shaft 1
Is provided with a slide switching device 30 for the pump drive cam 3, which is as follows. A spring receiver 31 is provided near the base end of the camshaft 1, and a cam spring 32 held by the spring receiver 31 biases the pump drive cam 3 toward the tip end of the camshaft 1. A flyweight 33 is swingably provided on the cam shaft 1 near the tip thereof. A collar 34 adjacent to the pump drive cam 3 is slidably fitted to the cam shaft 1 on the side near the tip thereof, and a lever arm 35 of a fly weight 33 is brought into contact with an end surface of the collar 34 to fly the cam shaft 1 during rotation. The pump drive cam 3 is pushed out to the base end side of the cam shaft 1 by the lever action of the weight 33 due to the centrifugal force.

As shown in FIG. 1 (B), while the cam shaft 1 is rotating, the pushing force of the fly weight 33 and the urging force of the cam spring 32 balance each other so that the pump drive cam 3 moves in the rocker arm interlocking posture 10. Can be maintained at. In the rocker arm interlocking posture 10, the input surface 9 of the rocker arm 4 contacts the cam surface 8 of the cam body 26. In addition, as shown in FIG.
While the rotation is stopped, the pump drive cam 3 is maintained in the rocker arm releasing posture 11 by the urging force of the cam spring 32. In this rocker arm release posture 11,
The input end portion 9 of the rocker arm 4 contacts the peripheral surface 28 of the small diameter portion 27, and is separated from the cam surface 8 of the cam body 26. When switching between the rocker arm interlocking attitude 10 and the rocker arm releasing attitude 11, the input end 9 of the rocker arm 4 is guided by the guide surface 29.

2A and 2B are explanatory views of a modification of the slide switching device. FIG. 2A is an explanatory view of a rocker arm interlocking posture of the pump drive cam, and FIG. 2B is an explanatory view of a rocker arm releasing posture of the pump drive cam. Is. In this modification, an electromagnet 36 is used instead of the flyweight 33, and a generator (not shown) linked to the crankshaft is connected to the electromagnet 36. As shown in FIG. 2 (A), while the engine is operating, electricity is supplied to the electromagnet 36 from the generator, and the repulsive force of the electromagnet 36 and the urging force of the cam spring 32 are balanced, whereby the pump drive cam 3
2 has a rocker arm interlocking posture 10, and as shown in FIG. 2 (B), the electromagnet 3 is stopped when the generator stops generating power while the engine is stopped.
The repulsive force from 6 is eliminated, and the pump drive cam 3 takes the rocker arm releasing posture 11 by the urging force of the cam spring 32.

The contents of the embodiment of the present invention are as described above, but the present invention is not limited to the above embodiment. For example, the sliding of the pump drive cam 3 is not limited to the case of being automatically performed by the slide switching device 30, but may be performed by a manual operation.

[Brief description of drawings]

1A and 1B are views for explaining a drive device of a fuel supply pump for an engine according to an embodiment of the present invention, FIG. 1A is a longitudinal sectional view of the drive device, and FIG. FIG. 1A is an explanatory diagram of a rocker arm interlocking posture of the pump drive cam in a cross section taken along the line BB of FIG. 1A, and FIG. 1C is an explanatory diagram of a rocker arm releasing posture of the pump drive cam.

2A and 2B are explanatory views of a modification example of a slide switching device, FIG. 2A is an explanatory view of a rocker arm interlocking posture of a pump drive cam, and FIG. 2B is a description of a rocker arm release posture of a pump drive cam. It is a figure.

FIG. 3 is a vertical cross-sectional view of a drive device for a fuel supply pump of an engine according to a conventional technique.

[Explanation of symbols]

1 ... Cam shaft, 3 ... Pump drive cam, 4 ... Rocker arm,
5 ... Fuel supply pump, 7 ... Manual operation lever, 8 ... Cam surface, 9 ... 4 input end, 10 ... Rocker arm interlocking posture,
11 ... Rocker arm release posture.

Claims (1)

[Claims] 1. A pump drive cam (3) is attached to a cam shaft (1) which is interlocked with a crank shaft, and the pump drive cam (3) is provided.
The fuel supply pump (5) is interlockingly connected to (3) through the rocker arm (4), and the rocker arm (7) is connected to the manual operation lever (7).
In a drive device for an engine fuel supply pump configured by interlocking (4), the pump drive cam (3) is slidably fitted to the cam shaft (1), and the pump drive cam (3) The cam surface
The rocker arm interlocking posture (10) in which the input end portion (9) of the rocker arm (4) is brought into contact with (8), and the input end portion (9) of the rocker arm (4) is detached from the cam surface (8) thereof. A drive device for a fuel supply pump of an engine, wherein a slide switch is possible in a rocker arm release posture (11).