JPH0640932Y2 - Unit type fuel injection pump device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a unit fuel injection pump device for delivering fuel to a combustion chamber of a compression ignition engine.

[Prior Art] A conventional apparatus will be described with reference to FIGS. As shown in FIG. 4, in the conventional unit type fuel injection pump device, a large number of parts constituting the pump device and the injector device are stacked and housed by a single elongated sleeve type nut 17.

The injection pump device portion is composed of a pump cylinder 1 for measuring the amount of fuel and increasing the pressure, a plunger 2 that reciprocates in the cylinder, a tappet 47 and a tappet spring 46 that drive the plunger, and the like.

The injector body portion includes a nozzle tip 4 for injecting fuel, a needle spring 8 for pressing a needle valve 6 of the nozzle tip against a valve seat of the nozzle tip, and a shim for adjusting a valve opening pressure of the needle valve 6. It comprises a needle spring 8 and a spring case 10 having a vertical hole 9 for accommodating a spring spacer and the like.

These components have a large number of step holes 11, 12, 13, 14, 15,
By the sleeve nut 17 forming the shoulder 16 in the holes 14 and 15, the shoulder is closely seated with the flange of the nozzle tip 4,
The components are stacked and housed inside a sleeve-type nut 17, and also have a large hole 18 and a small hole 19, and a shoulder 21 of a housing 21 forming a shoulder 20 is seated in close contact with the pump cylinder 1. , The housing 21 is engaged with the upper end screw 22 of the sleeve-type nut 17 and is tightened to hermetically hold the components. The pump cylinder 1 has a small hole 23 communicating with the inner pump chamber 24, and the pump cylinder 1 and the housing
An annular fuel pool 25 is formed by 21 and the sleeve type nut 17, and an O-ring 26 is provided between the housing 21 and the sleeve type nut 17 in order to keep the fuel pool oiltight. The fuel leaking from the nozzle tip 4 is the vertical hole 9 in the spring case.
Bleed off from the passage 27 communicating with the fuel pool 25.

[Problems to be solved by the device]

However, the conventional unit type fuel injection pump device has the following problems.

(1) A large number of components such as the nozzle tip 4, the spring case 10, the fuel pump cylinder 1 are stacked and tightened between a single sleeve type nut 17 and the housing 21. In order to maintain the hydraulic pressure at the high pressure sealed end faces of the joints of many of these components, a high degree of processing precision is required, and if this is not satisfied, leakage will occur in the high pressure fuel flow.

(2) Normally, only the nozzle tip 4 needs to be replaced or cleaned, because only the nozzle tip 4 is directly exposed to the severe environment in the engine combustion chamber (not shown). In the conventional unit type fuel injection device, it is necessary to disassemble the entire injection pump device for repair and regeneration.

(3) It is necessary to adjust the injection timing and the nozzle tip valve opening pressure after assembling this injection device, but it is necessary to incorporate dedicated jigs into each of them, and then disassemble and reassemble after adjustment. is there.

(4) To adjust the injection timing, as shown in FIG. 5, remove the sleeve-type nut 17 from the unit type fuel injection pump device and take out the fuel injection device component including the nozzle tip 4, the spring case 10 and the like. Jig instead of parts
50 is hermetically held by the shoulder 38 of the stepped hole by the sleeve type nut 17, and the plunger 2 is pushed down by the tappet 47,
From 53, the injection timing is known from the presence or absence of fuel discharge from the pump chamber 24.

The adjustment of the valve opening pressure of the needle valve 6 of the nozzle tip 4 is carried out by engaging the fuel injection device components in the sleeve type nut 17 with the screw 22 of the jig 52 and hermetically holding them as shown in FIG. Externally pressurized fuel is injected from the fuel inlet hole 55 of the jig 52 and adjusted.

In either case, disassembly of the fuel injector component and the fuel pressurizer component is required.

The object of the present invention is to solve the problems of the conventional device, and the pump assembly and the injection device body are independently sealed and held by a holding body, which facilitates manufacture and facilitates services such as adjustment and assembly. A unit fuel injection device is provided.

[Means for Solving the Problems]

The unit type fuel injection pump device of the present invention comprises a pump assembly in which an assembly of a pump cylinder and a plunger, a tappet, a tappet spring and the like are detachably assembled to a pump housing through a first sleeve type nut; a nozzle tip; An injection device body in which a needle spring or the like is detachably assembled to a spring case through a second sleeve type nut, and the pump assembly and the injection device body are connected through screws at respective ends. The feature is that they are assembled in a detachable manner.

[Action]

By providing two joints for separately and hermetically tightening the internal components, the unitary fuel injection pump device can be more easily assembled and repaired and can be tightened within the pump assembly and the injector body. In addition, there are advantages that the number of internal components is reduced, the high pressure fluid of the injection pump device is prevented from leaking, and the two large assembly parts are divided, which facilitates the manufacturing and adjusting service.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is an overall configuration diagram of the present invention, FIG. 2 is an explanatory diagram of the same injection timing adjustment example, and FIG. 3 is an explanatory diagram of the same valve opening pressure adjustment example.

The unit type fuel injection pump device of the present invention is divided into two parts, a pump assembly 3 and an injector device 48. The upper part of the unit type fuel injection device is composed of an assembly of the pump cylinder 1 and the plunger 2, a tappet 47, a tappet spring 46, a rack & pinion for measuring the injection amount, a housing 21, etc., which are exactly the same as the conventional example The pump assembly 3 has a housing 21 clamped to the cylinder head by clamps and bolts, as is well known in the art.
However, unlike the conventional one, the lower part of the injection device is composed of a second sleeve type nut 28 and the like which detachably holds components such as the nozzle tip 4, the needle valve spring 8 and the like via the spring case 34, It is possible to remove only the injector device 48 or the nozzle tip 4 from the pump assembly 3 or assemble them without the need to disassemble the first sleeve type nut 33.

The pump assembly 3 is composed of a pump cylinder 1, a plunger 2, a plunger driving device, a fuel metering device, etc., and has a large number of step holes 11, 29, 30, 31 and a shoulder 32 is formed by the step holes 30, 31. 1 of the housing 21 which is seated hermetically on the pump cylinder 1 at the shoulder portion by the sleeve type nut 33, accommodates the components in the sleeve type nut, and has shoulders 20 having large and small holes 18 and 19. The shoulder seats sealingly on the pump cylinder 1, the screw 22 of the first sleeve-type nut 33 engages the housing 21 and is tightened to hermetically retain the components. The pump cylinder 1 has a small hole 23 communicating with the inner pump chamber 24.
21 and the first sleeve type nut 33 form a fuel pool 25, and an O-ring 26 is provided between the housing 21 and the first sleeve type nut 33 in order to keep the fuel pool oiltight.

The injection device body 48 includes a nozzle tip 4, a needle valve 6, a spacer 5, a shim 7 for adjusting the nozzle opening pressure of the nozzle tip, and a needle valve spring 8.
With the second sleeve type nut 28 having the small holes 35, 36, 37 and the shoulder 38 formed by the holes 36, 37, the flange portion of the nozzle tip 4 is seated in the shoulder portion, and the component parts are Spring case
It is held at 34 and constitutes the injection device body 48. The screw 49 of the spring case 34 engages and tightens the first sleeve type nut 33 with the injection device body 48 to hermetically hold the components. Fuel leaking from the nozzle tip 4 is bleed off from the spring case vertical hole 9 through a hole 40 communicating with the fuel reservoir 25.

Next, the operation of the above embodiment will be described.

In order to adjust the injection timing first, the plunger 2 is pushed down by the tappet 47 in the state shown in FIG.
The injection timing is determined by whether fuel is discharged from 24. Even when the second sleeve type nut 28 is removed and the nozzle tip 4 is removed, the injection timing can be similarly determined.

FIG. 3 shows a method for adjusting the valve opening pressure of the needle valve 6 according to the present invention. Remove the fuel injector 48 and attach the jig 51.
Adjust by injecting external pressurized fuel from 54.

In either case, the work can be performed while keeping the housing 21 sealed, without changing the positions and the positions of the housing 21 and the pump cylinder 1.

[Effect of device]

According to the present invention, the pump assembly and the injection device body are hermetically held by independent holding bodies, and the components can be attached and detached without disturbing the other assembly. The service of adjusting the valve pressure and disassembling / assembling is easy, and since there are few parts that are stacked and clamped by one holding body, there is little risk of high-pressure fuel leakage.

[Brief description of drawings]

1 to 3 relate to the present invention, FIG. 1 is an overall configuration diagram, FIG. 2 is an explanatory diagram of the same injection timing adjustment example, FIG. 3 is an explanatory diagram of the same valve opening pressure adjustment example, and FIG. FIG. 6 is a conventional example, FIG. 4 is the correspondence diagram of FIG. 1, FIG. 5 is the correspondence diagram of FIG. 2, and FIG.
FIG. 1 ... Pump cylinder, 2 ... Plunger, 3 ... Pump assembly, 4 ... Nozzle tip, 8 ... Needle valve spring, 21 ... Housing, 28 ... Second sleeve type nut, 33 ... First Sleeve nut, 39 ... screw, 46
...... Tappet spring, 48 ...... Injection device body, 49 ...... Screw.

Claims (1)

[Scope of utility model registration request] 1. A pump assembly in which an assembly of a pump cylinder and a plunger, a tappet, a tappet spring and the like are detachably assembled to a pump housing via a first sleeve type nut; and a nozzle tip, a needle spring and the like are second. An injector assembly detachably assembled to the spring case via a sleeve-type nut; the pump assembly and the injector assembly are integrally detachably assembled via screws at respective ends. A unit type fuel injection pump device characterized by the above.