JPH0429852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention enables the timing set on the engine side and the pump side to be easily set with appropriate precision when attaching the cover of the timer (fuel injection timing adjustment device) connected to the fuel injection pump to the engine block. This article relates to a device that enables this.

In a fuel injection type engine, the injection timing of fuel supplied from a fuel injection pump is adjusted by a timer according to the operating condition of the engine, and for this reason, the fuel injection pump, timer, and engine are connected in this order. When such a connection is made, the injection pump and tires are assembled in advance, and then the timer is connected to the engine. In this case, the pump body, timer cover, and cylinder block will be connected, but in this case, the crank angle position on the engine side and the fuel injection timing on the pump side must be connected in a predetermined correspondence relationship. It won't happen. For example, when a particular cylinder in an engine is at a timing determined by output, fuel efficiency, exhaust gas, etc.
The pump that injects fuel into the cylinder must also be set at the same time as the fuel injection timing.

Conventionally, when connecting a timer cover to an engine block, the drive gear on the engine side is set at a predetermined angular position so that the above-mentioned specific cylinder has a predetermined timing. Turn the driven gear by hand so that the mark and the alignment mark formed on the driven gear on the timer side match, and fix the cover to the engine block so that both gears mesh at the position where the alignment marks match. Ta. If the alignment mark of the driven gear coincides with the alignment mark of the driving gear, the pump that supplies fuel to the specific cylinder is set to be in the fuel injection timing position.

However, if a specific pump is adjusted to the injection timing position by manually turning the driven gear,
The camshaft connected to the driven gear is pushing up the tappet with its cam surface, and the returning force of the spring for returning the tappet is also acting. Therefore, when turning the driven gear by hand, it is necessary to turn the driven gear against the frictional resistance of the tapepet and the return force of the spring, making the manual turning operation difficult. In addition, the state in which the cam surface is pushing up the tappet is an extremely unstable position, and if you remove your hand, the camshaft, or in other words, the driven gear, will immediately rotate, causing problems such as making it difficult to align the alignment marks. Ta.

Even if the position of the driven gear is adjusted so that it faces the driving gear when the injection pump and timer are assembled, vibrations may occur due to the unstable posture while transporting the pump and timer assembly. etc., the driven gear will be rotationally displaced. Therefore, when assembling the timer cover to the engine block, it is not easy to set the driven gear and the driving gear so that they are in a position at a predetermined timing.

The present invention has been developed based on the above circumstances, and its purpose is to enable the engine side and pump side to be set at a predetermined timing when assembling the timer cover to the engine block. It is an object of the present invention to provide a timing setting device for a fuel injection pump that facilitates installation work and allows highly accurate timing setting.

That is, in the present invention, the timer cover and the rotating member inside the cover are fixed with a fixing member in an attitude in which the camshaft is at a predetermined timing position, and when the cover is assembled to the engine block, the driving gear, the driven gear, etc. The power transmission system of the engine side and the pump side are automatically matched according to predetermined timing postures, making assembly easier, and the adjustment mechanism adjusts for dimensional variations during staking and assembly. It is characterized by being able to perform highly accurate timing set.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

In the figure, 1 is an engine block, and a cover 3 of a timer 2 is fixed to the engine block 1 in a predetermined position by bolts 4 .
A main body 6 of a fuel injection pump 5 is fixed to a cover 3 of the timer 2 at a predetermined position with bolts 7 .

A drive gear 8 that rotates in synchronization with a crankshaft (not shown) is provided within the engine block 1, and a driven gear 9 on the timer 2 side meshes with this drive gear 8. Rotation of the drive gear 8 is transmitted to the drive flange 10 by a driven gear 9. The drive flange 10 revolves small eccentric cams 12, 12 constituting a double eccentric cam mechanism via pins 11, 11, which are also shown in FIG. ,13
revolve.

The large eccentric cams 13, 13 are attached to a driven flange 15 formed integrally with the driven hub 14, so that the revolution of the large eccentric cams 13, 13 causes the driven flange 15 and the driven hub 14 to rotate. The driven hub 14 is integrally connected to a camshaft 16 by a round nut 17, and rotation of the driven hub 14 drives the camshaft 16.

A camshaft 16 extends into the pump body 6 and operates a tappet (not shown) to drive the pump plunger. This pump plunger therefore supplies fuel under pressure.

When hydraulic oil is introduced from a port 20 attached to the cover 3 depending on the operating condition of the engine, this hydraulic oil pushes the piston 22 in the pressure chamber 21 to the right in FIG. 1. The piston 22 moves on the inclined surface 22a,
The slider 23 is moved in the outer radial direction via 23a. As shown in FIG. 2, the slider 23 is
A pair of sliders 23 and 23 are arranged on the outer periphery of the driven hub 14, and these sliders 23 and 23 are arranged on the outer periphery of the driven hub 14, respectively.
4 and 24 to the large eccentric cams 13 and 13. Therefore, when the sliders 23, 23 are moved in the outer radial direction by the action of the piston 22, the large eccentric cam 1 is moved through the pins 24, 24.
3 and 13 are rotated in the direction of arrow A in FIG. 2, and at this time, the small eccentric cams 12 and 12 are rotated in the direction of arrow B, thereby moving the pins 11 and 11 in the direction of arrow C. As a result, the drive flange 10 and the driven flange 15 are angularly displaced relative to each other in the circumferential direction, thereby adjusting the advance or retard angle. As a result, the injection timing of the fuel supplied from the pump 5 is adjusted according to the operating conditions of the engine.

Note that 25 is a guide rod that guides the sliders 23, 23, and 26... is a spring that returns the sliders 2, 23 toward the center.

In this embodiment, the plate 30 is attached to the timer cover 3 with bolts 31, 31. In this case, the plate 30 has long holes 3
2 and 32, and this plate 30 forms the cover 3.
The position can be adjusted in the circumferential direction relative to the A screw hole 33 is formed in this plate 30, and a bolt 34 is detachably attached to the screw hole 33. The tip of the bolt 34 enters a locking hole 35 formed in the driven flange 15 as a rotating member, so that the bolt 35 can fix the driven flange 15 non-rotatably. Note that the driven flange 15
The position where is fixed by the bolt 35 is a state in which the camshaft 16 places a predetermined pump in the injection timing position.

According to such a configuration, with the pump 5 and the timer 2 connected by the bolts 7..., the driven gear 9 is turned by hand, and the locking hole 3 of the driven flange 15 is turned.
5 to face the screw hole 33 of the plate 30. Then, a bolt 34 is screwed into the screw hole 33, and the driven flange 15 is fixed with this bolt 34. In this state, the posture of the driven gear 9 is such that the camshaft 16 maintains the specific pump in the posture of the injection timing, and even if the driven gear 9 is not held down by hand, the bolt 34 is driven by the driven gear 9. Since the flange 15 is fixed, the driven gear 9 will not rotate. In other words, the driven gear 9 is supported with respect to the cover 3 in a predetermined timing posture.

The position of the drive gear 8 on the engine block 1 side is set so that a predetermined cylinder has a predetermined timing, and the cover 3 is attached to the bolt 4...
When attached to the engine block 1, the driven gear 9 is engaged with the drive gear 8 at a predetermined timing. Thereafter, the bolt 34 is removed, and a blind plug (not shown) is screwed into the screw hole 33 to prevent oil leakage, and the assembly is completed.

Note that the fact that the plate 30 is movable in the circumferential direction through the long holes 32, 32 is due to the fact that the driven flange 1
5 is fixed in place with the bolt 34, the camshaft 16 may not maintain the proper injection timing posture for a particular pump due to machining errors in the pump 5 or timer 2. This is absorbed by adjusting the position of the plate 30, that is, by relative displacement of the cover 3 in the circumferential direction. Because of this, the engine side and the pump side are connected with high precision at a predetermined timing.

5 to 7 show another embodiment of the present invention, in which the plate 30 described above is not used and the bolt 34 is screwed directly into the cover 3. Then, at the position of the bolt 7 for attaching the cover 3 to the pump body 6,
As shown in FIG. 7, the insertion holes 51 are elongated holes. Therefore, the position of the cover 3 can be adjusted in the circumferential direction relative to the pump body 6, and therefore it absorbs variations in processing and assembly of the pump 5 and the timer 2, and the bolts 34 are used to attach the driven flange. When the camshaft 15 is fixed, the camshaft 16 can be maintained at a predetermined timing posture.

In the above embodiments, a case has been described in which hydraulic control is performed using hydraulic oil to adjust the injection timing, but the present invention is not limited to this, and as is already known, a timer operated by centrifugal force can be used. It is also possible to carry out the method using weights.

Further, when power is transmitted from the engine side to the timer side, the power transmission means is not limited to the meshing of the driving gear 8 and the driven gear 9, but may be a connecting structure such as a flange or a coupling.

As detailed above, according to the present invention, before connecting the timer cover to the engine block,
Since the rotating members inside the cover are fixed with bolts at predetermined timing positions, the posture of the camshaft is maintained in the predetermined position when connecting the cover, and the power transmission system such as the driven gear can be held down by hand when connecting the cover. Since there is no need to keep the parts in place, the connection work is facilitated, and the engine side and pump side can be set at a predetermined timing. Moreover, since the timer cover can be moved relatively in the circumferential direction using an adjustment means, it is possible to absorb processing and assembly errors in the pump and timer and fix the camshaft in a highly accurate timing position relative to the cover. Highly accurate timing set is possible.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a cross-sectional view taken along the line in FIG. 2, FIG. 2 is a cross-sectional view taken along the line in FIG. 1, and FIG. is a cross-sectional view taken along the line in FIG. 1, and FIG. 4 is a sectional view taken along the line in FIG. 3. 5 to 7 show other embodiments of the present invention, FIG. 5 is a cross-sectional view, and FIGS. 6 and 7 are respectively shown in FIG.
FIG. 1...Engine block, 2...Timer, 3
... Cover, 5 ... Fuel injection pump, 6 ... Pump body, 8 ... Drive gear, 9 ... Driven gear, 16
...Camshaft, 30...Plate, 31...
Bolt, 32... Long hole, 33... Screw hole, 34...
...Bolt, 35...Lock hole.

Claims (1)

[Claims] 1. In a device in which the main body of the fuel injection pump is attached to the engine block via a timer cover, and the timing of fuel injection from the injection pump is adjusted by the timer according to the rotational speed of the engine, the timer cover and the An adjustment mechanism that fixes the rotating member of the timer by a removable connecting member, and adjusts the relative movement of the cover in the circumferential direction at the connecting portion between these covers and the rotating member, or at the connecting portion between the cover and the pump body. A timing set device for a fuel injection pump, characterized in that it is provided with a timing set device.