JP2005146984A - Fuel injection pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a lubricating oil from mixing into a fuel oil along the sliding face of a plunger by discharging the lubricating oil having entered a tappet chamber to the outside of the tappet chamber. <P>SOLUTION: In the fuel injection pump 1, parts of a driving system in a cam chamber 13 are lubricated by the lubricating oil of an engine. In a pump housing 2, an interconnection path 20 is provided so as to allow the tappet chamber 15 to communicate with a gear case 9 provided between the engine and the fuel injection pump, and an interconnection path 12c is provided so as to allow an inside space 12b of a tappet 12 to communicate with the interconnection path 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel injection pump having a structure in which a plunger in a plunger barrel is moved up and down by a cam, and in particular, by discharging the lubricating oil that has entered the tappet chamber to the outside of the tappet chamber, the lubricating oil is supplied to the plunger. The present invention relates to a structure for preventing fuel oil from being mixed along a sliding surface.

2. Description of the Related Art Conventionally, a fuel injection pump having a configuration in which a cam shaft supported by a housing is driven by an engine, a plunger is moved up and down by a cam provided on the cam shaft, and fuel oil is compressed by the plunger is known. (For example, refer to Patent Document 1).
In this conventional configuration, lubricating oil is supplied into a cam chamber formed in the housing, and the drive system components such as the cam and gears are lubricated by the lubricating oil. The lubricating oil lubricates the engine and also functions as a lubricating oil in a gear case interposed between the engine and the fuel injection pump. Between the gear case and the cam chamber, The lubricating oil is circulated through the circulation path.

Further, the plunger is supported by a plunger barrel so as to be slidable up and down. When the lower portion of the plunger is pressed upward by the cam via the tappet, the plunger moves upward and is formed above the plunger. The fuel oil in the fuel pressure chamber is compressed.
Further, in the pump housing, a tappet chamber is constituted by a sliding hole formed in a cylindrical shape in the vertical direction, and the tappet is slidably disposed in the tappet chamber. In the space above the tappet, a plunger spring that biases the plunger downward, a control sleeve for controlling the injection amount by rotating the plunger, and the like are disposed.

JP 2003-254186 A

In the conventional configuration, lubricating oil may enter the tappet chamber, and there is a risk that this lubricating oil may enter the fuel chamber through the clearance of the sliding surface between the plunger and the plunger barrel. there were.
If lubricating oil is mixed in the fuel oil, an injection failure may occur in the fuel injection nozzle, or a failure may occur in the pumping stage to the injection nozzle, leading to deterioration in engine performance such as a reduction in output.
Therefore, in a fuel injection pump configured to lubricate the drive system components in the cam chamber with engine lubricating oil, it is necessary to prevent the lubricating oil from being mixed into the fuel oil.

On the other hand, as described above, the lubricating oil lubricates the engine, the gear case, and the fuel injection pump, and it is necessary to circulate the lubricating oil between them.
Conventionally, the lubricating oil is circulated through the circulation path between the cam chamber and the gear case, but the gap between the cam surface and the cam chamber is narrow, and the presence of the cam circulates the lubricating oil. There was a problem that was disturbed.

In view of the above problems, the present invention discharges the lubricating oil that has entered the tappet chamber to the outside of the tappet chamber, thereby preventing the lubricating oil from being mixed into the fuel oil along the sliding surface of the plunger. This is a proposal.
In addition, a technique for improving the circulation of lubricating oil between the cam chamber and the gear case is proposed.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, as described in claim 1, in the fuel injection pump configured to lubricate the drive system components in the cam chamber by the engine lubricating oil,
In the pump housing,
A first communication passage is provided for communicating the tappet chamber with a gear case interposed between the engine and the fuel injection pump.

Further, as described in claim 2, the tappet is
A second communication path that communicates the internal space of the tappet with the first communication path is provided.

Further, as described in claim 3, in the fuel injection pump configured to lubricate the drive system components in the cam chamber with engine lubricating oil,
In the pump housing,
A communication path that connects the tappet chamber and the cam chamber is provided.

According to a fourth aspect of the present invention, there is provided a fuel injection pump configured to lubricate a drive system component in a cam chamber with engine lubricating oil.
The pump housing is provided with a communication passage that communicates the space before and after the cam in the cam chamber at a position on the outer side in the radial direction of the cam.

  As effects of the present invention, the following effects can be obtained.

  That is, according to the first aspect of the present invention, the lubricating oil that has entered the tappet chamber can be discharged to the gear case, so that the lubricating oil does not accumulate in the tappet chamber, and the lubricating oil is retained between the plunger and the plunger barrel. It is possible to prevent the air from entering the fuel pressure chamber through the clearance of the sliding surface. Thus, the lubricating oil is not mixed into the fuel oil, and problems such as injection failure and output reduction can be prevented.

  Further, in the invention according to claim 2, the lubricating oil that has entered the tappet chamber can be discharged through the communication passage to the communication passage, and more reliably compared to a configuration that does not constitute the communication passage. The lubricating oil can be discharged out of the tappet chamber.

  According to the third aspect of the present invention, the lubricating oil that has entered the tappet chamber can be discharged to the cam chamber, so that the lubricating oil does not accumulate in the tappet chamber, and the lubricating oil is not collected between the plunger and the plunger barrel. It is possible to prevent the air from entering the fuel pressure chamber through the clearance of the sliding surface. Thus, the lubricating oil is not mixed into the fuel oil, and problems such as injection failure and output reduction can be prevented.

  In the invention according to claim 4, even when the gap between the cam surface of the cam and the cam chamber is narrow, the lubricating oil is smoothly circulated through the communication path. Can be made.

  For the purpose of preventing the lubricant from entering the fuel oil through the sliding surface of the plunger by discharging the lubricant that has entered the tappet chamber to the outside of the tappet chamber, the tappet chamber, the engine This is achieved by providing a communication path that communicates between a fuel case and a gear case interposed between the fuel injection pump and the fuel injection pump.

Next, embodiments of the present invention will be described with reference to the drawings.
1 is a side cross-sectional view showing an example of a fuel injection pump in the first and second embodiments, FIG. 2 is a plan sectional view of a pump housing taken along line AA in FIG. 1, and FIG. 3 is a first and second embodiment. FIG. 4 is a side sectional view showing an example of a fuel injection pump in the first and second embodiments, and FIG. 5 is a side sectional view showing a main part configuration in the third embodiment. FIG. 6 is a plan sectional view, and FIG. 7 is a view showing the arrangement of the communication passages of the fourth embodiment.
In the following description, the left side in FIG. 1 is the front side, and the right side is the rear side.

As shown in FIG. 1, the fuel injection pump 1 is configured by joining a pump housing 2 and a hydraulic head 3 vertically.
A governor device 4 is disposed on the front side of the pump housing 2.
A gear case 9 is disposed on the rear side of the pump housing 2.

Further, a plunger barrel 8 is inserted into the hydraulic head 3, and a plunger 7 is slidably mounted in the plunger barrel 8, and by rotation of a cam 6 formed on the pump cam shaft 5, The plunger 7 is configured to move up and down via the tappet roller 11 and the tappet 12.
The space above the plunger 7 serves as a fuel pressure chamber 19 so that the plunger 7 compresses fuel oil flowing from a fuel gallery (not shown).

The tappet 12 is provided above the cam 6 and slidably up and down in a slide hole 15a formed in the hydraulic head 3 in the vertical direction.
The cam 6 is disposed in a cam chamber 13 formed in the hydraulic head 3.
The pump camshaft 5 is fixedly provided with a camshaft flange 14 housed in the gear case 9 so that the driving force from the engine is transmitted through the camshaft flange 14.

As shown in FIG. 2, in the pump housing 2, circulation paths 16 and 16 are formed for communicating the internal spaces of the cam chamber 13 and the gear case 9.
Lubricating oil is circulated between the cam chamber 13 and the gear case 9 through the circulation paths 16 and 16, and in the cam chamber 13, the cam 6, the bevel gears 17a and 17b, the bearing 18 and the like (see FIG. 1). The drive train components are lubricated, and a gear train (not shown) is lubricated in the gear case.

Next, the structure regarding the principal part of this invention is demonstrated using FIG.
As shown in FIG. 3, in the pump housing 2, a sliding hole 15a is formed in the vertical direction above the cam 6 formed on the pump cam shaft 5, and the tappet chamber 15 is formed in the sliding hole 15a. It is composed. A tappet 12 is arranged in the tappet chamber 15 so as to be movable up and down.
A tappet roller 11 is rotatably supported by the tappet 12, and the tappet 12 moves up and down via the tappet roller 11 as the cam 6 rotates.
The tappet 12 is formed in a bowl shape whose upper side is opened by an annular wall portion 12a. The inside of the wall 12a is defined as an internal space 12b, and the lower end of the plunger 7 and the lower spring receiver 31 are inserted into the internal space 12b from above.
The upper portion of the lower spring receiver 31 is locked to the lower end portion of the plunger 7.
A ring 32 is interposed between the lower surface of the lower spring receiver 31 and the bottom of the internal space 12b.

An upper spring receiver 33 is fitted over the tappet 12 in the sliding hole 15a. The upper end of the upper spring receiver 33 is held down by the hydraulic head 3. The upper spring receiver 33 is formed in a cylindrical shape, and a control sleeve 41 is rotatably disposed inside the cylinder.
A plunger spring 34 is sandwiched between the upper spring receiver 33 and the lower spring receiver 31, and the lower spring receiver 31 is biased downward by the plunger spring 34, whereby the plunger 7 is It is biased downward.
Further, the upper spring receiver 33 is formed in a cylindrical shape whose lower part is opened by an annular wall 33a. And the upper part of the said plunger spring 34 is inserted in the internal space 33b formed of this wall part 33a.
Further, the sliding portion 15a and the internal space 2a of the pump housing 2 are divided by the wall portion 33a.

  With the above configuration, the tappet chamber 15 separated from the internal space 2 a of the pump housing 2 is formed by the internal space 12 b of the tappet 12 and the internal space 33 b of the upper spring receiver 33.

In the pump housing 2, a wall portion 2b on the gear case 9 side is formed with an upper and lower communication passage 20a and a left and right communication passage 20b. A series of communication passages 20 (first passages) are formed by these passages 20a and 20b. A communication path) is formed.
The vertical communication path 20a is formed in an oblique shape, and the upper side is opened to the sliding hole 15a, while the lower side is opened to the left and right communication path 20b. The left and right communication paths 20 b are closed at the front end and opened at the rear end in the gear case 9. Thus, the inside of the sliding hole 15a and the inside of the gear case 9 are communicated with each other via the communication path 20.
The tappet 12 moves up and down in the sliding hole 15a, and a gap 36 is formed between the wall portion 12a of the tappet 12 and the wall portion 33a of the upper spring receiver 33. The tappet chamber 15 communicates with the upper and lower communication passages 20a through the upper and lower sides.

  With the above configuration, the tappet chamber 15 and the gear case 9 are communicated with each other via the gap 36 and the communication path 20.

  As described above, in the pump housing 2 of the fuel injection pump 1, the tappet chamber 15 separated from the internal space 2a of the pump housing 2 is formed, and the pump housing 2 includes the tappet chamber 15, the engine, A first communication passage 20 is formed to communicate with the gear case 9 interposed between the fuel injection pump 1 and the lubricating oil that has entered the tappet chamber 15 from the tappet chamber 15. It can be discharged to the gear case 9.

  As described above, when the lubricating oil that has entered the tappet chamber 15 is discharged to the gear case 9, the lubricating oil does not accumulate in the tappet chamber 15, and the lubricating oil is retained between the plunger 7 and the plunger barrel 8. It is possible to prevent the air from entering the fuel pressure chamber through the clearance of the sliding surface. Thus, the lubricating oil is not mixed into the fuel oil, and problems such as injection failure and output reduction can be prevented.

As described above, in the tappet 12, since the internal space 12b (see FIG. 3) is formed by the annular wall portion 12a, there is a possibility that the lubricating oil may accumulate in the internal space 12b. This is because in the configuration of the first embodiment, only the lubricating oil overflowing from the wall portion 12a can be discharged.
Therefore, in the second embodiment, as shown in FIG. 3, in addition to the first embodiment, the tappet 12 is connected to the internal space 12 b of the tappet 12 and the first communication path 20. The communication path 12c is provided.

  The wall portion 12a is provided with an internal space 12b and a communication passage 12c communicating with the upper and lower communication passages 20a, and the internal space 12b and the upper and lower communication passages 20a communicate with each other through the communication passage 12c. As a result, the lubricating oil in the tappet chamber 15 can be discharged through the communication passage 12c to the communication passage 20 (upper and lower communication passages 20a), and more reliably compared to those not constituting the communication passage 12c. The lubricating oil can be discharged out of the tappet chamber 15.

  Further, the communication path 12c is arranged at a position where the lower part of the communication path 12c communicates with the lower part of the internal space 12b of the tappet 12. It can be discharged to the (upper and lower communication passages 20a) side. Thereby, it can prevent that lubricating oil accumulates in the internal space 12b.

In this embodiment, as shown in FIGS. 4 to 6, in a fuel injection pump 100 in which the drive system components in the cam chamber 13 are lubricated by engine lubricating oil, a tappet chamber 15 and a cam The communication path 120 for communicating with the chamber 13 is provided.
As shown in FIG. 5, in the pump housing 102, a sliding hole 15a is formed in the vertical direction above the cam 6 formed on the pump cam shaft 5, and the tappet 12 is formed in the sliding hole 15a. It is arranged so that it can move up and down.
A tappet roller 11 is rotatably supported by the tappet 12, and the tappet 12 moves up and down via the tappet roller 11 as the cam 6 rotates.
The tappet 12 is formed in a bowl shape whose upper side is opened by an annular wall portion 12a. The inside of the wall 12a is defined as an internal space 12b, and the lower end of the plunger 7 and the lower spring receiver 31 are inserted into the internal space 12b from above.
The upper portion of the lower spring receiver 31 is locked to the lower end portion of the plunger 7.
A ring 32 is interposed between the lower surface of the lower spring receiver 31 and the bottom of the internal space 12b.

An upper spring receiver 133 is fitted over the tappet 12 in the sliding hole 15a. The upper end of the upper spring receiver 133 is held down by the hydraulic head 3. The upper spring receiver 133 has a cylindrical shape, and a control sleeve 41 is rotatably disposed inside the cylinder.
A plunger spring 34 is sandwiched between the upper spring receiver 133 and the lower spring receiver 31, and the lower spring receiver 31 is biased downward by the plunger spring 34. It is biased downward.
Further, the upper spring receiver 133 is formed in a cylindrical shape whose lower part is opened by an annular wall part 133a. And the upper part of the said plunger spring 34 is inserted in the internal space 133b formed of this wall part 133a.
As described above, the tappet chamber 115 is formed by the internal space 12 b of the tappet 12 and the internal space 133 b of the upper spring receiver 133.
Further, a gap 136 is formed between the wall portion 133 a of the upper spring receiver 133 and the wall portion 12 a of the tappet 12, and the internal space 102 a of the pump housing 102 is communicated with the gap 136. The tappet chamber 115 is communicated with the tappet chamber 115.

As shown in FIGS. 4 and 5, in the pump housing 102, a communication groove 120 a is formed that extends obliquely forward from the upper opening of the sliding hole 15 a.
In the pump housing 102, a communication hole 120b is formed from the bottom surface of the communication groove 120a toward the cam chamber 13, and a series of communication paths 120 are formed by the communication groove 120a and the communication hole 120b. It has become.

  With the above configuration, the tappet chamber 115 and the cam chamber 13 communicate with each other via the gap 136 and the communication path 120.

  As described above, in the pump housing 102 of the fuel injection pump 100, the communication passage 120 for communicating the tappet chamber 15 and the cam chamber 13 is formed in the pump housing 102, whereby the tappet chamber is formed. Lubricating oil that has entered into 115 can be discharged from the tappet chamber 115 to the cam chamber 13.

  As described above, when the lubricating oil that has entered the tappet chamber 115 is discharged to the cam chamber 13, the lubricating oil does not accumulate in the tappet chamber 115, and the lubricating oil is retained between the plunger 7 and the plunger barrel 8. It is possible to prevent the air from entering the fuel pressure chamber through the clearance of the sliding surface. Thus, the lubricating oil is not mixed into the fuel oil, and problems such as injection failure and output reduction can be prevented.

  In this embodiment, as shown in FIGS. 2 and 7, in the fuel injection pump in which the drive system components in the cam chamber 13 are lubricated by the lubricating oil of the engine, the pump housing 2 has a cam 6 radially outside. The communication passages 50 and 50 for communicating the spaces 13a and 13b before and after the cam chamber 13 in the cam chamber 13 are provided at the positions.

As shown in FIGS. 2 and 7, in the pump housing 2, circulation passages 16 and 16 are formed to communicate the internal spaces of the cam chamber 13 and the gear case 9, thereby the cam chamber 13 and the gear. Lubricating oil is circulated between the cases 9.
Groove-shaped communication passages 50 and 50 are formed at positions on the outer side in the radial direction of the cam 6 so that the spaces 13a and 13b before and after the cam chamber 13 communicate with each other. Connected to form a continuous passage.
As shown in FIG. 2, the communication passages 50 and 50 are inclined so that the groove depth increases from the front space 13 a side of the cam chamber 13 toward the rear space 13 b.

With the above configuration, even when the gap between the cam surface of the cam 6 and the cam chamber 13 is narrow, the lubricating oil is smoothly circulated through the communication paths 50 and 50. be able to.
Further, the communication passages 50, 50 can be prevented from being excessively accumulated in the front space 13a by being inclined as described above.
In this embodiment, the groove-shaped communication passages 50 and 50 are used. However, any structure may be used as long as the spaces 13a and 13b before and after the cam chamber 13 communicate with each other. However, the specific configuration is not particularly limited.

  The present invention is applicable to a fuel injection pump configured to lubricate drive system components in a cam chamber with engine lubricating oil.

It is side surface sectional drawing which shows the example of the fuel-injection pump in Example 1 and Example 2. FIG. FIG. 2 is a plan sectional view of the pump housing taken along line AA in FIG. 1. It is side surface sectional drawing shown about the structure of the principal part of Example 1 and Example 2. FIG. It is side surface sectional drawing which shows the example of the fuel-injection pump in Example 1 and Example 2. FIG. FIG. 10 is a side cross-sectional view showing the configuration of the main part of Example 3. It is a plane sectional view similarly. It is a figure shown about arrangement | positioning of the communicating path of Example 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection pump 2 Pump housing 9 Gear case 12 Tappet 12b Internal space 12c Communication path 13 Cam chamber 15 Tappet chamber 20 Communication path

Claims (4)

In the fuel injection pump configured to lubricate the drive system components in the cam chamber with engine lubricating oil,
In the pump housing,
Provided a first communication path for communicating the tappet chamber and a gear case interposed between the engine and the fuel injection pump;
A fuel injection pump characterized by that. To the tappet,
A second communication path is provided for communicating the internal space of the tappet with the first communication path;
The fuel injection pump according to claim 1. In the fuel injection pump configured to lubricate the drive system components in the cam chamber with engine lubricating oil,
In the pump housing,
A communication path that connects the tappet chamber and the cam chamber is provided.
A fuel injection pump characterized by that. In the fuel injection pump configured to lubricate the drive system components in the cam chamber with engine lubricating oil,
The pump housing is provided with a communication path that communicates the space before and after the cam in the cam chamber at a position that is radially outward of the cam.
A fuel injection pump characterized by that.