JPH0217176Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a unit injector injection pump.

[Conventional technology and its problems]

As is well known, in the case of a normal injection device for a diesel engine, an injection pump and an injection nozzle are connected by an injection pipe with a length of several hundred mm. Due to this length and associated volume, it is not possible to inject from the injection nozzle exactly as delivered from the injection nozzle's plunger. For example, even if the cam angle during the period of delivery from the plunger is the same, the injection timing becomes longer with the rotation speed, the injection delay angle becomes larger, the injection amount cannot be controlled as desired in the small injection amount region, and other problems. It is the cause of Therefore, if the injection pump and the injection nozzle are integrated, this problem should be solved, and the unit injector has realized this problem.

However, even with such a unit injector, it is not possible to completely adjust it in a bench test, and maintenance adjustment is easier with a normal fuel injection system.For example, with a unit injector, the injection pump and injection nozzle are Therefore, when attempting to mass-produce this, the timing at which the plunger of the injection pump starts pumping fuel toward the nozzle side tends to vary due to assembly errors in the axial direction. Therefore, in the past, in order to make the plunger's fuel injection start timing constant, there was a provision for making the length of the connection between the tappet and the rocker arm relatively variable (for example,
This purpose is achieved by selecting the metal balls (see illustrations in Japanese Patent No. 57-92804 and Japanese Utility Model Application No. 57-49564) from among a large number of different thicknesses.

However, if this selection work is performed as part of a series of engine manufacturing processes, the dowels will not fall off after they are assembled, but in the case of manufacturing a unit injector alone, such dowels will not fall off. Once the money is dropped, there is a risk that it may be mixed up with other winnings or that other winnings may be mistakenly included.

[Means for solving problems]

Therefore, the present invention solves this problem with a simple device, which makes maintenance and adjustment easy.
The purpose is to provide a unit injector that facilitates the attachment and detachment of the snap spring used, and its gist is to provide a unit injector that is slidably inserted into a barrel 10 and is pressed by a rocker arm 3; , a stiff return spring 18 provided on the outer periphery of the barrel 10 and returning the plunger 8, a tappet 21 integrally formed with the upper spring receiver 20 for receiving the return spring 18, and the plunger. Provided at the upper end of 8,
The opening 3 of the tapepet 21 is centered on its axis.
a driving lever 23 that rotates the plunger 8 in an opening range of 1; The axial adjustment device for the unit injector is provided with a dowel 25 which is detachably fixed to the inner periphery of the tappet 21 by a dowel snap ring 26.

〔Example〕

Hereinafter, the configuration of the present invention will be described in detail based on embodiments shown in the accompanying drawings. FIG. 1 is a longitudinal sectional view of this embodiment, and FIG. 2 is a plan view of FIG. 1.

In these diagrams, 1 is the cylinder head, 2 is the combustion chamber, and 3 is the cylinder head.
is the Rocker arm, 4 is the unit injector,
Reference numeral 5 indicates a mounting arm, and 6 indicates a mounting bolt of the mounting arm 5. Therefore, the unit injector 4 is fixed to the cylinder head 1 by the mounting arm 5, and is driven by the rocker arm 3.
The structure is such that fuel is injected into the combustion chamber 2.

This unit injector 4 is provided with a plunger 8 above and an injection nozzle 9 connected above and below on the axis of the case body 7. The plunger 8 is slidably inserted into the barrel 10, and the needle valve 11 is slidably built into the injection nozzle 9. A cap 12 is screwed onto the lower part of the case body 7, and the cap 12 holds the injection nozzle 9.

A feed hole 13 is provided in the barrel 10, and the feed hole 13 communicates with an oil reservoir chamber 14. The oil reservoir chamber 14 communicates with a supply passage 15 from a feed pump (not shown) and a discharge passage 16, and a throttle passage 17 is interposed between the oil reservoir chamber 14 and the discharge passage 16. A lower spring receiver 19 that receives the return spring 18 is slidably fitted on the outer periphery of the barrel 10 , and the lower spring receiver 19 is screwed onto the case body 7 .

An upper spring receiver 20 for receiving the return spring 18 is provided above the return spring 18, and a tappet 21 having the upper spring receiver 20 as a stepped portion is provided. The tappet 21 is slidably fitted into the case body 7. A flange 22 of the plunger 8 is placed above the upper spring receiver 20, and a driving lever 23 is fixed to the top of the flange 22. The driving lever 23 is rotated by the swinging of a governor lever (not shown). A stopper 25 having a flange 24 is placed on the upper end surface of the plunger 8, and the stopper 25 is removably fixed to the inner circumference of the tappet 21 by a snap ring 26 embedded in a ring groove 36 of the tappet 21.

Reference numeral 27 denotes a maximum injection amount adjusting projection, and the projection 27 is eccentrically provided to protrude from a rotating shaft 28, and the rotating shaft 28 is also rotated by an adjusting bolt 29. The protrusion 27
is inserted into a long hole 30 formed in the axial direction of the tappet 21, and allows the tappet 21 to rotate about its axis. Therefore, Tappet 2
By changing the opening direction of the fan-shaped opening 31 opened on one side of the fuel injection valve 1, the contact position of the driving lever 23 for the maximum injection amount can be changed.

Reference numeral 32 is a non-return valve in the form of a star-shaped plate valve, which is constructed in two stages and corresponds to a normal delivery valve.

Since this embodiment has the above configuration, the fuel introduced from the oil reservoir chamber 14 through the feed hole 13 becomes high pressure as the plunger 8 presses down, and is introduced into the needle valve 11 from the supply path 33. The needle valve 11 opens against the elasticity of the pressure spring 34, and the fuel is transferred to the combustion chamber 2.
gushes out. A notch 35 is formed on the outer periphery of the plunger 8.
, the effective compression stroke of the plunger 8 is adjusted by rotating the driving lever 23. Then, the pressure drop of the plunger 8 is
This is done by pressing the rocker arm 3 together with the tappet 21 via the stopper 25 against the elastic force of the return spring 18 by swinging the rocker arm 3.

Note that although the non-return valve 32 is configured as a star-shaped plate valve, it goes without saying that it may also be a ball valve.

[Effect of idea]

According to this invention, since the axial adjustment of the plunger of the unit injector, that is, the adjustment of the fuel injection timing, is performed using the money, it is possible to mass produce the unit injector alone, and it can also be applied to multi-cylinder engines. Even if the unit injector is operated, the adjustment is easy and the reliability of the unit injector is improved.Moreover, since the charge is fixed inside the tappet which is essential for the unit injector, there is no fear of loss of the charge. In turn, this has the great benefit of improving the productivity of the unit injector and making it easier to adjust the engine performance.

In addition, the opening of the tappet for the driving lever was used to insert an expandable snap spring for fixing the stopper, making it possible to secure the optimum stopper without the need for a special structure. However, in addition to receiving the above-mentioned great benefits, the snap spring can be replaced very easily.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a plan view of FIG. 1. 3...Rotzker arm, 4...Unit injector, 8...Plunger, 18...Return spring, 21...Tappet, 25...Block, 26...
Snut spring.

Claims (1)

[Claims for Utility Model Registration] A plunger 8 that is slidably inserted into the barrel 10 and is pressed by the rocker arm 3.
a return spring 18 provided on the outer periphery of the barrel 10 for returning the plunger 8; and an upper spring receiver 20 for receiving the return spring 18.
a driving lever 23 that is provided at the upper end of the plunger 8 and rotates the plunger 8 within the opening range of the opening 31 of the tappet 21 around its axis; In the unit injector, the inner periphery of the tappet 21 is provided between the upper end surface of the plunger 8 and the rocker arm 3 and expandable at the opening 31 of the tappet 21. An axial adjustment device for a unit injector, comprising a dowel 25 which is detachably fixed to the unit injector.