JPS6034774Y2 - Fuel injection pump metering device - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a small and compact sleeve metering type fuel injection pump.

[Conventional technology and its problems]

Conventionally, sleeve metering type fuel injection pumps equipped with an annular valve (sleeve) that is slidably inserted into the lower body of the plunger have been disclosed in Japanese Utility Model Publication No. 53-7201 and Japanese Utility Model Publication No. 55-243.
This method is known from Japanese Utility Model Publication No. 71 and Japanese Utility Model Application Publication No. 55-139262.

Such conventional sleeve metering type fuel injection pumps all have inclined lead parts for control on the upper and lower end surfaces of the annular valve or on the intermediate body, so the outer peripheral gear that rotates the annular valve has If rigidity cannot be obtained, and an attempt is made to provide rigidity, the length of the annular valve itself in the axial direction becomes too large, and its weight also increases, making it unsuitable for a small and compact fuel injection pump.

[Means for solving problems]

Therefore, the present invention was devised to eliminate such conventional problems, and the configuration of the present invention will be explained in detail based on the embodiments shown in the accompanying drawings.

First, the outline of this embodiment is shown in FIG. 1, which shows a four-cylinder fuel injection pump 1, which is driven by {circle around (2)} camshafts 2. In FIG.

A governor housing 4 is attached to one side of the pump body 3, forming an integral pump housing as a whole.

The main parts will be explained separately below.

Regarding the fuel injection pump 1 alone, 5 is a plunger, which has an oil hole 6 in its center that communicates with the lower body from the discharge hole in the head, and an annular valve 7 is slid in the lower body of the plunger 5. The annular valve 7 is movably inserted into the annular valve 7 and is provided with a control port 8 bored in the radial direction.

Further, the annular valve 7 is configured with a gear 9 carved on its outer periphery and a fitting groove 10 provided on the lower side, with which the control rack meshes, and rotation by the gear 9 and fitting groove 10 are configured. The controller is moved up and down by an eccentric pin (not shown) engaged with the controller 10.

Therefore, the communication time or timing between the oil hole 6 and the control port 8 and the size of the communicating portion are controlled, and the fuel injection rate and injection time are controlled.

11 is a tappet, and a roller 12 is held by the tappet 11.

13 is a bowl-shaped spring holder that receives a plunger spring that presses the plunger 5 in the camshaft direction; 14 is a barrel; 15 is a valve holder for a delivery valve; and 16 is a high-pressure pipe installation leading to a fuel injection valve (not shown). 17 is a barrel holder, 18 is a delivery valve, 19 is a valve seat, 20 is a wall extending from the pump body 3 and partitioning between the column fuel injection pumps 1, and 21 is a communication hole in the wall 20. shows.

The roller 12 is held by the tappet 11,
The axial direction of the roller 12 is controlled by a roller guide pin 23 rotatably inserted into the outer peripheral end of the bearing metal 22 of the camshaft 2 or the lower end of the wall portion 20.

Regarding the cam bearing 2, it is placed horizontally on the pump body 3 on the lower side of the row-type fuel injection pump 1, and the large-diameter bearing portions 25, 26 on both sides are connected via the bearing metals 22, 24. supported.

A gear (not shown) is provided at one outer end and is driven by a crankshaft (not shown).

The size of these bearing portions 25 and 26 is such that the roller 12 prevents the roller 12 from being removed from the cam 2 in the axial direction.
7, it is formed to the size of the vertical movement stroke.

On the other outer end of the camshaft 2, further outside the spline 29 for the vane pump 28 and the weight support 38, a fitting part 32 for a governor spindle 31, which opens and closes the governor weight 30 and slides therewith, is provided protrudingly. are doing.

Regarding the vane pump 28' (this is a rotary pump composed of an eccentric piston and a partition plate), the vane pump 28' is mounted on the outside of the bearing part 26 of the camshaft 2.
Eight side casings 33 degrees, a central casing 34, and other side casings (which serve as a plate for the thrust axis of the governor weight force 30) are arranged side by side on the camshaft 2 in a skewered manner.

These members 33 , 34 are fixed to the pump body 3 by a plurality of through bolts 37 .

The eccentric rotor 35, which is concentric with the central casing 34, is provided with a spline that engages with the spline 29, and is connected to the camshaft 2.
The rotation of the partition plate (vane) causes the partition plate (vane) to protrude due to centrifugal force.

The vane pump 28 pumps a fuel tank (not shown).
Since more fuel is pressurized into the pump body 3 and the governor housing (up to approximately 10 to 9/art), the inside of the pump housing is filled with fuel.

Regarding the governor device, the weight support 38 is a donut-shaped disk, and the camshaft 2 is mounted in the center of the weight support 38.
A spline that engages with the spline 29 is carved, and a disc-shaped projection (not shown) is provided on the projection, and four governor weights 30 are provided on the projection so that they can be opened and closed with weight pins 39. .

The governor weight 30 has a pawl 40, and the pawl 4
0 is in contact with a flange 41 of a governor spindle 31 fitted to the tip of the camshaft 2.

If the engine speed, that is, the rotation speed of the camshaft 2 increases,
The governor weight 30 is opened by centrifugal force, and the pawl 40 advances the governor spindle 31.
1, a rack (
(not shown).

That is, the annular valve 7 is controlled by the rack.

Here, when the governor weight 30 opens, its thrust is received by the side casing 36 of the vane pump 28 via the weight support 38, so in particular, the camshaft 2 itself is not provided with a thrust bearing.

Note that 43 is an injection amount limiting device that adjusts the governor link 42 from the outside, 44 is an overflow valve for fuel in the pump housing, and 47' is a snap ring.

In particular, the present invention is constructed as follows.

That is, in the fuel injection pump equipped with the annular valve 7,
The plunger 5 has a vertical oil hole 6 in its center that communicates with the discharge hole in the head, and the oil hole 6 is connected to a suction hole 45 in the lower body of the plunger 5 in the radial direction. It is opened by a hole 46.

In order to open and close these suction holes 45 and oil leak holes 46, the annular valve 7 is fitted into the plunger 5.

The annular valve 7 is formed to have a constant wall thickness in the axial direction so as not to impair the rigidity of the gear on its outer periphery.

On the other hand, an inclined lead groove 47 is formed on the outer circumferential surface of the plunger 5 near where the oil leak hole 46 is opened, and a control port is formed in the annular valve 7 in the radial direction. 8 and communicate with each other.

Therefore, by rotating the gear 9, its communication position is controlled and the amount of fuel discharged is adjusted.

Further, by vertical movement of the eccentric pin engaged with the fitting groove 10, the lower end face of the annular valve 7 controls the closing timing of the suction hole 45 and adjusts the start of fuel discharge.

Furthermore, the plunger 5 is pushed up by the rotation of the camshaft 2, and the suction hole 45 and oil leak hole 46 are opened and closed by the annular valve 7, thereby controlling the amount and discharge timing of the fuel.

In summary, since the present invention adopts the structure described in the claims for utility model registration, it has the following effects.

[Effect of idea]

■ According to the present invention, the annular valve to which the controller (rack or eccentric pin) for controlling the amount and timing of fuel injection is engaged has a length in the axial direction, that is, a wall thickness. Since the thickness is constant, the rigidity of the gear carved on the outer periphery of the annular valve can be particularly increased, and the wall thickness of the annular valve can be reduced, reducing the weight of the annular valve and reducing the sliding of the plunger. Minimizing the moving parts improves the responsiveness of fuel injection pump control.

■ The present invention forms a lead groove for control on the outer circumferential surface of the plunger, but this formation is different from the conventional production technology of drilling the outer circumferential surface of the plunger in conventional Bosch fuel injection pumps. Since it can be used for other purposes, its processing is easier than forming a lead surface on an annular valve, and production costs can be reduced.

■ The suction hole is drilled on the opposite side of the oil leak hole, so
No side pressure is generated on the plunger, allowing smooth sliding between the annular valve and the plunger.

(2) Rotation of the annular valve changes the direction of oil leakage ejected from the control port drilled there, and cavitation erosion that occurs in other pump members due to the oil leakage can be avoided.

[Brief explanation of the drawing]

Figure 1 is an overall front view, Figure 2 is a diagram of the main parts of the plunger,
FIG. 3 shows a cross-sectional view of the plunger and the annular valve. 5...Plunger, 6...Oil hole, 7.
...Annular valve, 8...Control port, 9...
... Gear, 45 ... Suction hole, 46 ...
...Oil leak hole, 47...Lead groove.

Claims (2)

[Scope of utility model registration request] (1) In a small sleeve metering type fuel injection pump equipped with an annular valve that is slidably inserted into the lower body of the plunger and has a gear carved on at least the outer periphery, the head part is placed in the center of the plunger. drilling an oil hole that communicates the discharge port with a radial suction hole and an oil leak hole drilled in the lower body,
An inclined lead groove is bored in the outer peripheral surface of the plunger near the opening of the oil leak hole, and the annular valve has a constant wall thickness in the axial direction, and a control port is bored in the radial direction. A metering device for a fuel injection pump, characterized in that communication between the lead groove and the control port is controlled by rotation of a gear of the annular valve. (2) The metering device for a fuel injection pump according to claim (1), wherein the suction hole, which is opened and closed by the end face of the annular valve, is formed on the opposite side of the oil leakage hole.