JPS6037611Y2 - row type fuel injection pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small and compact size fuel injection pump, particularly to a sleeve metering type fuel injection pump.

Regarding the conventional fuel injection pump, as shown in Japanese Utility Model Publication No. 55-24371 devised by one of the inventors of the present invention, an annular valve fitted into the lower body of the plunger rotates and moves up and down. There are sleeve metering type fuel injection pumps that meter the amount of fuel.

Therefore, the present invention was devised to develop a size-type fuel injection pump in which multiple fuel injection pumps are arranged side by side. While avoiding the tendency for bulkiness due to the large number of overlapping parts, such as fitting and inserting a control sleeve that meshes with a control rack, we also want to eliminate the difficulty of increasing the pressure of a distribution type fuel injection pump that has a sleeve metering mechanism. It was devised during the development of a large-sized fuel injection pump.

This will be explained based on the embodiment shown in the drawings. In general, as shown in FIG. 1, four four-cylinder fuel injection pumps 1 are arranged in parallel and are driven by {circle around (2)} camshafts 2.

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

Each major part 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 from the head to the lower body, and an annular valve 7 is fitted into the lower body of the plunger 5.
The annular valve 7 is provided with a control port 8, and the annular valve 7 is rotated by a gear 9 carved on its outer periphery and by an eccentric pin (not shown) engaged with a fitting groove 10 provided on the lower side. It moves up and down, controls the communication time or timing between the oil hole 6 and the control port 8, and the size of the communicating portion, and limits the fuel injection rate and injection timing.

A tappet 11 holds a roller 12.

13 is a bowl-shaped spring holder equipped with 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 attachment leading to a fuel injection valve (not shown). 17 is a barrel retainer, 18 is a delivery valve, and 19 is a valve seat.

Reference numeral 20 denotes a wall section extending from the pump body 3 and partitioning between the fuel injection pumps 1 arranged in parallel, and a communication hole 21 is provided in the middle thereof.

Further, the roller 12 is connected to the tappet 11 as described above.
The axial direction of the roller 12 is adjusted by a roller guide pin 23 rotatably inserted into the outer peripheral end of the bearing metal 22 for the camshaft 2 or the lower end of the wall 20. It is being said.

Next, talking about the camshaft 2, it is mounted horizontally on the pump body 3 on the lower side of the square-shaped fuel injection pump 1, and the bearing metals 22, 2
4.

One outer end thereof is provided with a gear (not shown) and is driven by a crankshaft (not shown).

These bearing portions 25 and 26 are sized to include the range of stroke in which the roller 12 is moved up and down by the cam 27 in order to prevent the roller 12 from being pulled out in the axial direction.

A spline 29 for the vane pump 28 and a weight support 38 is carved on the other outer end of the camshaft 2, and a governor that slides as the governor weight 30 opens and closes further outside the carved spline 29. A fitting portion 32 of the spindle 31 is provided in a protruding manner.

Next, regarding the vane pump 28 (this is a rotary pump composed of an eccentric piston and a partition plate), the side casing 33, the central casing 34 and Other side casing (this is governor weight 30
(which serves as a thrust bearing plate) are skewered and arranged side by side on the camshaft 2.

These members are fixed to the pump body 3 with 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 vane causes the partition plate (vane) to protrude due to centrifugal force.

This vane pump 28 pumps fuel from a fuel tank (not shown) into the pump housing formed by the pump main body 3 and the governor housing 4.
C1ft), the inside of this pump housing is filled with fuel.

Next, talking about the governor device, the weight support 38 is a donut-shaped disc, and a spline that engages with the spline 29 of the camshaft 2 is carved in the center of the weight support 38, and a protrusion is provided on the disc surface. Four governor weights 30 are provided on the protrusion with weight pins 39 so as to be openable and closable.

The governor weight 30 has a pawl 40, which abuts against a flange 41 of a governor spindle 31 fitted to the tip of the camshaft 2.

When the engine rotation speed, that is, the rotation speed of the camshaft 2 increases, the governor weight 30 opens due to centrifugal force, and its pawl 40 advances the governor spindle 31.
With the head of 1, a governor link 42 (only a part of which is shown) is interlocked to horizontally move a rack that meshes with gear 9 of annular valve 7.

The annular valve 7 is controlled by the rack.

Here, when the governor weight 30 opens, its thrust is supported by the side casing 36 of the vane pump 28 from the weight support 38, so especially the camshaft 2
It does not have a thrust bearing, simplifying its structure.

Note that 43 is an injection amount control 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 the illustrated size-type fuel injection pump having such a configuration,
A camshaft 2 driven by a crankshaft (not shown) rotates a cam 27, a vane pump 28, a governor weight 30, etc., and depending on the vane pump, fuel from a fuel tank (not shown) is forced into the pump housing. and fill it up.

Further, the cam 27 is caused to reciprocate with the plunger 5 of each fuel injection pump 1, and intermittently pumps the fuel filled around the tappet 11 to a fuel injection valve (not shown).

Further, depending on the governor weight 30, it opens and closes depending on the magnitude of the engine speed, interlocks the governor link 42, and controls the amount of each fuel injection pump 1.

Here, the present invention, as shown in FIGS. 2 and 3,
A groove 46 deeper than the bottom groove of the spline 29 is provided in the circumferential direction at the fitting portion of the weight support 38 in the spline 29 provided on the camshaft 2, and a C-shaped snap ring 47 is installed in the groove 46 in the radial direction. The fitting part of the weight support 38 is provided with an inner circumferential groove 48 in which the weight support 38 can be slightly slid by the thrust of the governor weight 30.

The depth of this inner circumferential groove 48 is made slightly smaller than the outer diameter of the snap ring 47, and
8 are coupled to each other by the radial tension of a snap ring 47.

Then, when the fuel pump 1 is disassembled, when the weight support 38 is pulled out from the camshaft 2, the snap ring 47 is compressed and can be easily disassembled.

In the rectangular fuel injection pump of the present invention having such a configuration, fuel is pressurized into the pump body 1 from the fuel tank by the vane pump 28, and this fuel, which is filled around the tappet 11, is delivered to the oil in the plunger 5 through the control port 8. The fuel is introduced into the hole 6 and is pumped to a fuel injection valve (not shown) by vertical movement by the cam 27 of the camshaft 2 rotated by the plunger 5.

By the way, in a conventional size pump in which Bosch type fuel injection pumps are arranged in parallel, a weight support 38 is inserted into the end of the camshaft and secured with a key, and a cap nut or ordinary nut is screwed onto the camshaft from the tip of the weight support 38 to secure the weight. Since the support is fixed, space is wasted, and special tools are required to attach and remove the nut due to the narrow space, making assembly and disassembly difficult.However, in the present invention, the weight support 38 is The process has become easier by simply inserting and pulling out.

In summary, the present invention connects a weight support 38 provided with a governor weight 30 to one end of a single camshaft 2 provided on the lower side of the size-type fuel injection pump 1 by a spline 29,
A radially expandable snap ring 47 is buried in the axial middle of the spline 29, and the weight support 38 and the camshaft 2 are connected to each other so as to be disassembled and reassembled, and the thrust movement of the weight support 38 is slightly allowed. Since it is a large size fuel injection pump, it has the following effects.

(2) Since the snap ring for the weight support 38 is provided at the spline joint, the length of the camshaft 2 in the axial direction is shortened, and the entire size-shaped fuel injection pump can be made compact.

■ Since the radially expandable snap ring 47 is buried in the middle of the spline 29, the weight support 3
To increase the durability of the snap ring 47, since the governor weight 30 can be easily attached and removed without using any tools by simply inserting and pulling out the snap ring 8, and is not subjected to any thrust by the governor weight 30. Can be done.

(2) Since the distance between the governor weight 30 and the rack can be shortened, the opening/closing movement of the governor weight 30 can be transmitted to the rack with good responsiveness.

[Brief explanation of drawings]

Figure 1 is an overall front view, Figure 2 is a view of the main parts of the camshaft, and Figure 3 is a front view of the entire body.
The figure shows a cross-sectional view of the weight support. 1... Fuel injection pump, 2... Camshaft, 29... Spline, 30... Governor weight, 38... Weight support, 47
...Snap ring.

Claims (1)

[Scope of utility model registration request] A weight support that supports the governor weight is spline-coupled to one end of a single camshaft provided on the lower side of the size fuel injection pump, and a radially expandable snap ring is embedded in the axial center of the spline. . A size-shaped fuel injection pump in which the weight support and the camshaft are connected to each other so that they can be disassembled and assembled, and the thrust of the weight support is allowed to move slightly.