JPH112162A - Distribution type fuel injection pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily demount a high-pressure pipe and a delivery valve by mounting the high-pressure pipe reaching the fuel injection valves, on a position separated from a plug, in a distribution type fuel injection pump where a gauge mounting part is installed on an upper edge in the sliding direction, of a plunger of the fuel injection pump, and closing the same by the screwing of the plug. SOLUTION: On the arrangement of a dial gauge G to be screwed on an upper face of a hydraulic head 1, three delivery valves 6 are projected on an position around a distribution shaft, and high-pressure pipes 26 are respectively connected with the delivery valves 6. A plug is mounted on a position bypassing the positions of the delivery valves 6 and the high-pressure pipes 26, and the dial gauge G is mounted after the plug, is demounted. By positioning the delivery valves 6, the high-pressure pipes 26 and the plug separately from each other, the mounting and demounting work can be improved when the dial gauge G and the plug are mounted and demounted. The dial gauge G comprises a sensor rod to be inserted into an inside of a plunger barrel, to use the same for the adjustment of the injection time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distribution type fuel injection pump for a diesel internal combustion engine, and more particularly to a configuration of a gauge mounting plug for adjusting an injection timing and a distribution shaft barrel which are mounted on a hydraulic head. .

[0002]

2. Description of the Related Art A technique related to a distribution type fuel injection pump has been conventionally known, for example, from Japanese Patent Application Laid-Open No. H8-100729.

[0003]

However, in the prior art, as shown in FIG. 9 and FIG.
The position of the plug P which is removed for screwing is close to the position of the delivery valve 6 for supplying high-pressure oil to each cylinder. For example, as shown in FIGS. , And it is difficult to replace the plug P with the dial gauge G.

Conventionally, a fuel passage T for supplying high-pressure oil from the upper part of the plunger 3 to the distribution shaft 5 through the inside of the plunger barrel 2 is formed as shown in FIGS. 9 and 12. is there. That is, in the case of the conventional configuration shown in FIG. 11, between the lower end surface of the plug P and the upper end of the plunger 3,
A space Q for storing high-pressure oil is formed, and a space for storing fuel unnecessarily is formed. As a result, there is a problem that the pump efficiency is reduced, and the injection pressure is reduced, thereby deteriorating the engine performance. When a projecting portion P1 having substantially the same shape is formed below the plug P as shown in FIG. 12, the fuel passage T is formed obliquely downward from a compression space formed at the top of the plunger barrel 2 and the plunger 3. Therefore, the drill processing becomes complicated and the cost increases. Also, since the load on the sealing surface is high, which deforms the plunger barrel 2 and causes seizure, there is a problem that the inner diameter of the barrel near the sealing surface needs to be stepped to secure a gap with the plunger 3. It was.

Further, in a structure in which the hydraulic head 1 and the pump drive housing 9 are vertically joined and the distribution shaft barrel 4 is fixed to the inside of the hydraulic head 1 by shrink fitting, the lower end of the distribution shaft barrel 4 is provided. The position of the lower end of the hydraulic head 1 was the same as that shown in FIG. Therefore, the oil-tight sealing surface between the distribution shaft barrel 4 and the distribution shaft 5 is not sufficient, and high-pressure oil leaks to the hydraulic head 1 side between the distribution shaft barrel 4 and the distribution shaft 5. There was.

According to the present invention, as described above, the distribution type fuel injection pump is improved in order to solve the above-mentioned three problems which have occurred in the conventional distribution type fuel injection pump.

[0007]

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described. The dispensing type fuel injection pump according to claim 1, wherein a portion for mounting a gauge for checking fuel injection timing is provided at an upper end in a sliding direction of the plunger, and the gauge mounting portion is usually screwed with a plug. In this configuration, the high-pressure pipe that passes through the distributor and reaches the fuel injection valve of each cylinder is disposed at a position separated from the plug.

According to a second aspect of the present invention, there is provided a distribution type fuel injection pump, wherein a part for mounting a gauge for checking fuel injection timing is provided at an upper end of a plunger in a sliding direction, and the gauge mounting part is usually provided with a plug. In the configuration in which the barrel is screwed and closed, a female screw hole for screwing the barrel into the plunger is provided, a projection is provided on the plunger side from the sealing surface of the female screw hole, and a fuel passage from the plunger to the distribution shaft is provided. It is transverse to the sliding direction of the plunger.

According to a third aspect of the present invention, in the structure in which the plunger barrel and the distribution shaft barrel are fixed to the hydraulic head by shrink fitting, the lower end surface of the distribution shaft barrel in which the distribution shaft is fitted is mounted on the hydraulic head and the pump drive. It projects from the joint surface with the housing toward the pump drive housing to form a sufficient sealing surface between the distribution shaft 5 and the distribution shaft barrel 4.

[0010]

Next, an embodiment of the present invention will be described. Embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a front sectional view of a two-shaft distribution type fuel injection pump, and FIG.
FIG. 3 is a side sectional view of the same, showing a structure provided with an electromagnetic solenoid 8 for driving a closing valve V1. FIG. 3 shows a state where a plug P of the hydraulic head 1 of the present invention is removed and a dial gauge G is mounted. FIG. 4 is a plan view of the same state as in FIG. 3, and FIG. 5 is a front sectional view of the state in which the distribution shaft barrel 4 and the distribution shaft 5 are projected from the hydraulic head 1 toward the pump drive housing 9.

FIG. 6 is a side sectional view of the distribution type fuel injection pump with the dial gauge G mounted thereon, FIG. 7 is an enlarged view of the dial gauge G, and FIG.
And FIG. 9 is a front sectional view showing the positions of the conventional delivery valve 6 and the plug P, and FIG. 10 is a front sectional view showing the positions of the conventional delivery valve 6 and the plug P. FIG. 11 is a plan view of a distribution type fuel injection pump, FIG. 11 is a sectional view showing a conventional structure of a plug P and a fuel passage T, and FIG. 12 is a sectional view showing a conventional structure of a plug P and a fuel passage T.

First, the schematic structure of a two-shaft distribution type fuel injection pump will be described with reference to FIGS. A cam shaft 10 connected to the output shaft of the diesel internal combustion engine is supported in the pump drive housing 9, and a cam 10a for driving the plunger and a gear 10b for driving the distribution shaft are formed on the cam shaft 10. A tappet mechanism 11 is in contact with the cam 10a, and a distribution shaft drive shaft 12 is in gear engagement with the gear 10b. As shown in FIG. 2, a fuel charge pump 13 driven by the camshaft 10 is attached to the front of the pump drive housing 9.
Introduce fuel from the fuel tank. 1 and 2, A is a fuel supply path, B is a fuel intake path, C is a fuel reservoir, D is a plunger chamber, E is a fuel pressure supply path, F is a fuel distribution path, K is a reverse suction path, and H Is a fuel discharge path, and V1 is a closing valve.

FIG. 1 shows a side view of the pump drive housing 9.
The governor housing 14 is connected to the camshaft 10 and the camshaft 10 which is rotatably supported in the pump drive housing 9 is inserted into the governor housing 14 to form a governor mechanism. The governor in this embodiment is a centrifugal mechanical governor, that is, a governor weight 15 is attached to the camshaft 10, and the governor weight 15 is adjusted according to the degree of opening of the governor weight 15 in proportion to the rotation speed of the camshaft 10. The governor rack 16 connected to the plunger 3 described later which fits inside the tappet mechanism 11
2 (shown in FIG. 2), the plunger 3 is rotated, and the amount of fuel pressure fed from the plunger 3 is adjusted. That is, the fuel injection amount is adjusted according to the engine speed.

The hydraulic head 1 is disposed on the pump drive housing 9.
The plunger barrel 2 and the distribution shaft barrel 4 are internally fitted so as to penetrate through the hydraulic head 1 and the hydraulic head 1. The plunger 3 is slidably and rotatably fitted inside the plunger barrel 2 to drive the pump. In the housing 9, the plunger 3 protrudes from the plunger barrel 2 and is fitted and connected to the tappet mechanism 11 so that the plunger 3 reciprocates by rotating the cam 10a. On the other hand, the distribution shaft 5 is rotatably fitted in the distribution shaft barrel 4, and the distribution shaft 5 is separated from the distribution shaft barrel 4 in the pump drive housing 9.
And is connected to the distribution shaft drive shaft 12. The hydraulic head 1 is further fitted with a delivery valve (discharge valve) 6 for a cylinder of a diesel internal combustion engine, each discharge port is protruded outside, and fuel is supplied to a fuel injection valve disposed in each cylinder. Discharge is supplied.

Further, as shown in FIG. 2, the electromagnetic solenoid 8 for controlling the on-off valve in the fuel supply path, which is the first feature of the fuel injection pump of the present invention, is fitted inside the hydraulic head 1 from the front side. I have. The hydraulic head 1 is provided with an oil passage and various valves, and the plunger barrel 2 is provided with ports 2a and 2b, for example, to form a control mechanism for fuel pressure feeding from the plunger 3 to the distribution shaft 5.

Next, referring to FIGS. 3 and 4, the arrangement of the dial gauge G screwed on the upper surface of the hydraulic head 1 will be described. In this embodiment, a case of a three-cylinder diesel engine is illustrated, and a position around the distribution shaft 5 is
Three delivery valves 6 protrude, and the high-pressure pipes 26 project from the delivery valve 6. The plug P is disposed at a position avoiding the positions of the delivery valve 6 and the high-pressure pipe 26. The plug P is removed and the dial gauge G is mounted.

As described above, the delivery valve 6 and the high-pressure pipe 2
6 and dial gauge G are separated,
When the dial gauge G and the plug P are attached and detached, the delivery valve 6 and the high-pressure pipe 26 are less hindered. The dial gauge G includes a sensor rod 24 fitted into the plunger barrel 2, a male screw body 25 screwed in place of the plug P, an instrument bracket 27 screwed on the male screw body 25, The instrument bracket 27 includes a push rod 23, a pressure oil outlet 29, and an instrument main body 30.

The dial gauge G is, as shown in FIG.
The plug P screwed to the hydraulic head 1 is removed, and the male screw 25 is screwed. Next, the configuration of the fuel passage T and the protrusion P2 of the plug P will be described with reference to FIG. Conventionally, it was configured as shown in FIG. 11 and FIG. That is, in the case of FIG. 11, a space Q is formed above the plunger 3 and the pump efficiency is reduced. Further, in the case of FIG. 12, the protruding portion P1 protrudes, but does not protrude into the hole of the plunger 3, but the fuel passage T is formed obliquely. In each case, a defect occurred.

In the case of the present invention, as shown in FIG. 8, a protruding portion P1 protrudes from the plug P, and a protruding portion P2 protrudes into a hole of the plunger 3, so that the fuel passage T is formed by the protruding portion P1.
It is bored in the horizontal direction from a slight space formed between the upper end of the plunger 3 and 2. Next, in FIG.
A configuration in which the distribution shaft barrel 4 protrudes by a distance t into a space formed in the pump drive housing 9 will be described. Conventionally, as shown in FIG. 9, both the distribution shaft barrel 4 and the distribution shaft 5 protrude only to the same position as the lower end surface of the hydraulic head 1. If the lengths of the distribution shaft barrel 4 and the distribution shaft 5 are short as in the related art, a surface for sufficiently sealing high-pressure oil could not be secured.

The present invention solves this problem by distributing the distribution shaft barrel 4 from the lower surface of the hydraulic head 1 further into the space of the pump drive housing 9 by a distance t, thereby distributing the distribution shaft barrel 4 to the distribution shaft barrel 4. A sufficient oil-tight space is formed between the shafts 5.

[0021]

According to the present invention having the above-described structure, the following effects can be obtained. A dispensing type fuel injection pump according to claim 1, wherein a portion for attaching a gauge for checking fuel injection timing is provided at an upper end in a sliding direction of the plunger, and the gauge attaching portion is usually screwed with a plug. Since the high-pressure pipes passing through the distributor and reaching the fuel injection valves of the respective cylinders are arranged at positions away from the plugs in the configuration for closing the valve, the high-pressure pipe 26 and the delivery valve 6 can be easily removed. . In addition, the high pressure pipe 26 and the delivery valve 6 do not hinder the attachment and detachment of the dial gauge G. Further, when the portion of the plug P is removed and the air in the distribution type fuel injection pump is removed from the portion, the operation is facilitated. In addition, the measurement accuracy for checking the fuel injection axis could be improved.

According to a second aspect of the present invention, in the distribution type fuel injection pump, a portion for mounting a gauge for checking fuel injection timing is provided at an upper end in a sliding direction of the plunger, and the gauge mounting portion is usually provided with a plug. In the configuration for screwing and closing, a female screw hole for screwing a barrel to the plunger is provided, a projection is provided on the plunger side from a sealing surface of the female screw hole, and a fuel passage from the plunger to the distribution shaft is provided. Is set to be transverse to the sliding direction of the plunger, so that the plunger 3
A wasteful space Q is not formed in a portion of the high-pressure oil pool above the oil pump, thereby improving the pump efficiency. In addition, the injection pressure of the distribution type fuel injection pump is increased to improve the injection characteristics. It is effective. In addition, seizure of the plunger 3 can be prevented.

According to a third aspect of the present invention, in the structure in which the plunger barrel and the distribution shaft barrel are fixed to the hydraulic head by shrink fitting, the lower end surface of the distribution shaft barrel into which the distribution shaft is fitted is driven by the pump of the hydraulic head. The sealing surface between the distribution shaft 5 and the distribution shaft barrel 4 is formed by projecting from the joint surface with the housing toward the pump drive housing and forming a sufficient sealing surface between the distribution shaft 5 and the distribution shaft barrel 4. , The leakage of the high-pressure fuel oil can be eliminated, and the dilution of the lubricating oil inside the distribution type fuel injection pump can be prevented.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a two-shaft distribution type fuel injection pump.

FIG. 2 is a side sectional view of the same, showing a structure provided with an electromagnetic solenoid 8 for driving a closing valve V1.

FIG. 3 is a front view of the hydraulic head 1 according to the present invention in a state where a plug P is removed and a dial gauge G is mounted.

4 is a plan view of the state shown in FIG. 3;

FIG. 5 is a front sectional view of a state in which the distribution shaft barrel 4 and the distribution shaft 5 are projected from the hydraulic head 1 in the direction of the pump drive housing 9.

FIG. 6 is a side sectional view showing a state in which a dial gauge G is mounted on the distribution type fuel injection pump.

FIG. 7 is an enlarged view of a dial gauge G.

FIG. 8 is a side cross-sectional view showing a state in which projecting portions P1 and P2 are formed from a plug P and project into a hole of the plunger barrel 2 in which the plunger 3 is fitted.

FIG. 9 is a front sectional view showing the positions of a conventional delivery valve 6 and a plug P.

FIG. 10 is a plan view of a conventional distribution type fuel injection pump.

FIG. 11 is a sectional view showing a conventional configuration of a plug P and a fuel passage T.

FIG. 12 is a sectional view showing a conventional configuration of a plug P and a fuel passage T.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic head 2 Plunger barrel 3 Plunger 4 Distribution shaft barrel 5 Distribution shaft 6 Delivery valve 8 Electromagnetic solenoid 9 Pump drive housing 10 Cam shaft

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Hattori 1-32 Chayacho, Kita-ku, Osaka-shi, Osaka Inside Yanmar Diesel Co., Ltd.

Claims (3)

[Claims] 1. A dispensing type fuel injection pump, wherein a part for attaching a fuel injection timing confirmation gauge is provided at an upper end in a sliding direction of a plunger, and the gauge attachment part is usually screwed with a plug. A dispensing-type fuel injection pump, wherein a high-pressure pipe that passes through a dispensing device and reaches a fuel injection valve of each cylinder is arranged at a position away from the plug in the closed configuration. 2. A distribution type fuel injection pump, wherein a portion for attaching a gauge for checking fuel injection timing is provided at an upper end in a sliding direction of a plunger, and the gauge attachment portion is usually screwed with a plug. In the closed configuration, a female screw hole for screwing a barrel into the plunger is provided, a projection is provided on the plunger side from a sealing surface of the female screw hole, and a fuel passage from the plunger to the distribution shaft is moved by sliding of the plunger. A distribution type fuel injection pump characterized in that it is oriented transversely to the direction. 3. In a structure in which a plunger barrel and a distribution shaft barrel are fixed to a hydraulic head by shrink fitting, a lower end surface of the distribution shaft barrel in which the distribution shaft is fitted is provided.
A distribution type fuel injection pump characterized in that a sufficient sealing surface is formed between the distribution shaft 5 and the distribution shaft barrel 4 by projecting from the joint surface between the hydraulic head and the pump drive housing toward the pump drive housing. .