JPS60132064A - Fuel injection pump - Google Patents

Abstract

PURPOSE:To certainly control the fuel injection amount for a long period by reducing the clearance between a plunger and a sleeve at the position opposed to the force transmitted from a control means side. CONSTITUTION:A control sleeve 20 has a projection part 40 which projects inwardly towards a large-diameter part 3b which crosses at right angles to the flat-surface part 32 of a plunger 3, at the position crossing at right angles to the fitting part 20b at the lower edge. Therefore, a clearance delta for permitting the reciprocating movement of the plunger 3 is provided between the projection part 40 and the large-diameter part 3b. Therefore, even if a ball 22 is provided with the force in the radial direction B by the control operation for the fuel injection amount, the large tilt of the sleeve 20 is prevented, since the clearance delta is small, and the biting-in of the upper edge part of the sleeve 20 into a cylinder 2 is suppressed. Therefore, the fuel injection amount can be certainly controlled for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fuel injection pump also known as a Bosch type, and particularly to a fuel injection amount control structure thereof.

[Technical background of the invention]

Conventionally, a fuel injection pump that supplies fuel to a diesel engine has a structure shown in FIGS. 1 to 3. That is, in the figure, 1 is a pump housing, and a cylinder 2 is provided inside the pump housing 1.
A plunger 3 is slidably inserted into the cylinder 2. The lower end of the granger 3 is in contact with a tappet assembly 5 via a snoring seat 4. The tappet assembly 5 has a cylindrical tappet with a roller pin 7 attached inside a di 6, and a cam roller 8 rotatably fitted into the roller pin 7. The cam roller 8 is in rolling contact with a camshaft 9 that rotates in synchronization with the engine, and the tappet assembly 5 is reciprocated by the rotation of the camshaft 90, so that the plunger 3 is reciprocated in the axial direction of the cylinder 2. It will be done. The return movement of the Hikoo plunger 3 is performed by a spring 10.

11 is a fuel intake hole opened in the side wall of the cylinder 2;
This fuel intake hole 11 is communicated with a fuel supply port 13 through a fuel reservoir 12. The syringer 3 has a spiral or other inclined lead 14 formed at its upper end, and when the lead 14 opens the fuel suction hole 11 when the plunger 3 moves downward, fuel is transferred from the fuel reservoir 12 to the pressure-feeding chamber 15. Introduce.

When the reed 14 closes the fuel intake hole 11 when the plunger 3 moves upward, the fuel in the pressure feeding chamber 15 is pressurized, and this fuel pushes open the discharge valve 16 and is forced to be fed from the fuel discharge port 17 to the engine side. .

Note that by operating the nut 18 and adjusting the set load of the spring 190, the opening pressure of the discharge valve 16 is varied and the fuel discharge pressure is adjusted.

Reference numeral 20 denotes a control sleeve, and its upper end portion 20a is fitted to the cylinder 2 so as to be rotatable.

Further, the lower end portion of this sleeve 20 is engaged with the plunger 3 so as to rotate integrally therewith. This engagement structure is shown in FIG. That is, a large diameter portion is formed in the middle of the sylanger 3, and planar portions 9a, 9a, which are cut to face each other, are formed in this large diameter portion. Opposed to this, the lower part of the sleeve 2O has a flat part 3a.
, 3h are formed. These flat parts 3h, 31L and fitting parts 20b, 20
By engagement with b, the sleeve 20 and the plunger 3 can rotate together around the axis. Note that during reciprocating movement of the syringer 3, only the plunger 3 moves in the axial direction.

A flange 21 is formed at the upper end of the sleeve 2O, and a nail 22 is brazed or welded to this flange 21. And pump housing 1 has rack 2
3 is attached, and the pole 22 is slidably held between arm portions 24 and 24 shown in FIG. 3 formed on this rack 23. Although not shown, the rack 23 responds to the operation of an accelerator operator and is moved in the direction of arrow A in FIG. 3 by means of a pannier.

Therefore, when the rack 23 is moved in the direction of arrow A, ?
- The control sleeve 2O is rotated because the control sleeve 22 is pushed in the circumferential direction of the sleeve.
The syringe 3 is also rotated by the same amount as the sleeve 20 because the rotation is transmitted to the planter 3 through the engagement of the sleeves 9a, 9a.

The rotation of the plunger 3 is caused by the inclined lead 14 and the fuel suction hole 11.
In order to change the relative position of the plunger 3,
The opening timing of the fuel suction hole 1 during the process is changed. Based on this, the fuel injection amount is controlled.

By the way, conventionally, a gap t is secured between the sleeve 20 and the large diameter portion 3b of the syringe 3 shown in FIG. The gap is set to 0.3 to 0.3 to reduce the frictional resistance with the sleeve 2O when the sylanger 3 reciprocates.
It had a clearance of about 0.5 mm.

[Problems with background technology]

However, when the sleeve 20 is rotated through the lever 22 by operating the rack 23 in the direction of arrow A, the lever 22 and the arm portion 24.24 are displaced relative to each other in the radial direction. If the contact resistance is large, pole 22
A force is generated that moves the radially. In such a case,
Since the sleeve 2O is fitted into the cylinder 2 only at its upper part, and in addition, a large gap t is ensured with respect to the syringe 3, the axis of the sleeve 2O is tilted. Due to this inclination, the upper end 20q of the sleeve 2O is
It often happens that the sleeve 20 is bitten into the cylinder 21 and the movement of the sleeve 2O is obstructed, making it impossible to control the fuel injection amount with high accuracy.

[Purpose of the invention]

The present invention was made based on the above circumstances, and its purpose is to prevent the sleeve from tilting, eliminate the occurrence of biting between the sleeve and the cylinder, and to control the fuel injection amount over a long period of time. The purpose is to provide a fuel injection pump that can be used reliably.

[Summary of the invention]

That is, in the present invention, since the inclination of the sleeve is caused by the fact that the direction of the force transmitted from the control means side, which is composed of a rack and a sol, coincides with the direction of the clearance t, A feature is that the gap between the silancia and the sleeve at a position opposite to the direction of the force transmitted from the silansha is a minute clearance. - [Embodiment of the Invention] An embodiment of the present invention will be described below based on FIGS. 4 and 5.

It should be noted that FIG. 4 shows an improved structure shown in the section ``■'' in FIG. 1, and since the other structures may be the same as those in FIGS. 1 and 3, their explanation will be omitted.

The control sleeve 20 of this embodiment has fitting parts 20b and 2 at the lower end.
At a position orthogonal to 0b, a flat part 3h of the shiransha 3,
A protrusion 40°4O is formed to face the large diameter portion 3b perpendicular to 3* and protrude inward. Therefore, the protrusion 4
0.40 and above! A clearance δ sufficient to allow reciprocating movement of the plunger 3 is provided between the large diameter portions 3b and 3b of the plunger 30, and δ is set to 0.1- or less.

According to such a configuration, even if a force is applied to the sleeve 22 in the radial direction (indicated by the direction of arrow B in FIG. It does not tilt, so the upper end of the sleeve 20 does not bite into the cylinder 2.

6 and 7 respectively show other embodiments of the present invention, in which the diameter of the peripheral wall 60.60 is reduced by drawing or other means instead of the protrusion 40.40. The clearance δ between the reduced diameter portion 60, 60 and the large diameter portions 3b, 3b is made very small (0°1 m or less).

Moreover, FIG. 7 shows the flat part 3m of the Granger 3.

This is an example in which the positions of 3a and large diameter portions sb' and sb are changed by 90 degrees compared to the conventional example shown in FIG.

Even if you do it this way? - Radial direction to rule 22 (direction of arrow B)
Even if the force is transmitted, the sleeve 20 will not be tilted because the clearance δ is small.

As can be seen from the drawings of FIGS. 5 to 7, the present invention
The clearance δ with respect to the direction of the force transmitted through the coil 22 is made minute, and as explained with reference to FIG. This will prevent the sleeve 2O from tilting.

In addition, in the present invention, the arm 9-24.24 is formed on the sleeve 20 side, and the goal 2 is formed on the rack) 3 side.
2 may be attached to control the rotation of the sleeve 2O.

〔Effect of the invention〕

As described above, according to the present invention, the clearance between the sleeve and the silansha at the position opposite to the force transmitted from the control means side is reduced, so the sleeve is prevented from tilting, and therefore the sleeve does not dig into the cylinder. . Therefore, the sleeve can be controlled reliably over a long period of time.
Control of fuel injection amount is maintained with high precision.

[Brief explanation of the drawing]

Figures 1 to 3 show a conventional fuel injection pump, with Figure 1 being an overall sectional view, and Figures 2 and 3 being cross sections taken along lines ■-■ and ■-■ in Figure 1, respectively. It is a diagram. 4 and 5 show an embodiment of the present invention, FIG. 4 is a cross-sectional view showing the improved structure of the section ``■'' in FIG. 1, and FIG. The cross-sectional views, FIGS. 6 and 7, are cross-sectional views showing other embodiments of the present invention. 1...Ponno housing, 2...Cylinder, 3...
・Plunger, 9...Camshaft, 11...Fuel suction hole, 14...Slanted lead, 16...Discharge valve, 20...
- Control sleeve, 22... Sol (control means), 23
...Rack (control means), 3m, 3h...Plane part,
3b, 3b...Large diameter part, 40.40...Protrusion, 6
O160...Reduced diameter part, δ...Minor clearance. Applicant's agent Patent attorney Takehiko Suzue 11-

Claims (2)

[Claims] (1) A plunger is slidably provided in the cylinder, and the plunger is reciprocated by a camshaft to inject fuel, and a control sleeve fitted to the cylinder so as to be rotatable in the circumferential direction is externally controlled. The sleeve is rotated through a mechanism, and the rotation of the sleeve is transmitted to the sylanger by the engagement of the sleeve with the flat part formed on the plunger, and as the plunger rotates, the inclined lead formed on the plunger and In a fuel injection pump that controls the fuel injection amount by adjusting the relative position with a fuel suction hole formed in the cylinder, the flat part of the syringer and the retaining part of the control sleeve are transmitted to the sleeve from the control means side. A fuel injection pump characterized by having a minute clearance between the plunger and the sleeve at positions facing each other in the direction of the force. (2) The fuel injection pump according to claim (1), wherein the minute clearance is formed by deforming the side wall of the sleeve toward the syringe.