JPS6350434Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that automatically adjusts fuel injection timing according to the rotational speed of an engine.

Generally, in a diesel engine or the like, the fuel injection timing is controlled to be advanced as the rotational speed is increased so that fuel injection is always performed at the highest pressure point.

A typical example of this type of fuel injection timing adjustment device (referred to as an automatic timer) is one in which the rotation of a drive flange connected to the engine is transmitted to a pair of timing weights, and these timing weights are displaced in the radial direction by centrifugal force. Then, this displacement is transmitted to the driven flange of the timing hub via the large eccentric cam and the small eccentric cam, and the timing hub is angularly displaced relative to the driving flange, thereby driving the fuel injection pump. It is known that the fuel injection timing is relatively advanced by rotating the shaft at an advanced angle.

By the way, conventionally, in the case of a timing weight that uses a timing weight that is displaced based on centrifugal force, its radial movement is guided by a thrust receiver such as a plate, and its return operation is performed by the urging force of a spring. It's getting old. However, in the case where the displacement of the timing weight is guided by a thrust receiver, the lubricating oil tends to be insufficient on the sliding surface between the timing weight and the thrust receiver, and a large amount of sliding occurs due to the displacement of the timing weight. You will encounter resistance. Therefore, the target timer characteristic A (N _p −θ characteristic, N _p is the pump rotation speed,
(θ is the advance angle), the characteristic actually becomes as shown in pattern B, and hysteresis occurs in the timer characteristic. Due to the kneading, a slight deviation occurs in the fuel injection timing, which is not desirable from the viewpoint of improving engine output and taking measures against exhaust emissions.

In addition, if there is a lack of lubricating oil not only on the sliding surface between the timing weight and the thrust receiver, but also on the sliding surface of the eccentric cam, etc., which is tightly fitted, seizure may occur on this sliding surface. It was easy to use and had problems from the viewpoint of durability.

The present invention was developed based on these circumstances, and its purpose is to efficiently supply lubricating oil to the sliding surfaces of each part, reduce hysteresis in timer characteristics, and improve durability. An object of the present invention is to provide a fuel injection timing adjustment device for an internal combustion engine that can achieve the following objectives.

In other words, the present invention forms a cylinder chamber into which lubricating oil is guided in the timing weight, connects this cylinder chamber and the sliding surface of the timing weight via a lubricating oil passage, and connects the timing weight to the cylinder chamber. It is characterized by being provided with a piston that slides as the weight expands and compresses lubricating oil in the cylinder chamber.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

In the figure, 1 is a gear that is meshed and driven by a crankshaft of an engine (not shown), and this gear 1 has a housing 2 integrally. A drive flange 4 is connected to the gear 1 via bolts 3...
The housing 2 and drive flange 4 rotate integrally.

The drive flange 4 is provided concentrically around the outer periphery of the timing hub 5, and is relatively rotatably supported by a stepped portion 7 of a driven flange 6 formed on the timing hub 5. The timing hub 5 is connected to a drive shaft 8 of a fuel injection pump (not shown) through a nut 9, and the drive shaft 8 rotates together with the timing hub 5.

Circular holes 10a and 10b are formed in the drive flange 4 at positions facing each other in the radial direction,
A large eccentric cam 11 is provided in these circular holes 10a and 10b.
a and 11b are rotatably fitted. Large eccentric cams 11a and 11b have circular holes 112a and 12b formed at eccentric positions, respectively, and disk-shaped small eccentric cams 13a and 13b are rotatably fitted into these circular holes 12a and 12b, respectively. ing. These small eccentric cams 13a, 13b are provided with second eccentric pins 14a, 14b protruding from eccentric positions, respectively.
4b is press-fitted into the driven flange 6. Further, first eccentric pins 15a, 15b are protruded from the large eccentric cams 11a, 11b at eccentric positions, respectively, and these first eccentric pins 15a, 15b are press-fitted into timing weights 16a, 16b.

The timing weights 16a and 15b surround the timing hub 5 and are divided in the radial direction, and are operated to expand each other based on centrifugal force. Support rods 17, 17 are loosely inserted between the timing weights 16a, 16b and located at both ends, respectively. Therefore, the timing weights 16a, 16b are guided by these support rods 17, 17 so that they can move in the radial direction. Spring receivers 19 are attached to both ends of the support rod 17 via retaining rings 18, and the spring receivers 19 and timing weights 16a, 16
A spring 20 is bridged between the Therefore, the springs 20... always press the pair of timing weights 16a, 16b in the direction of approaching each other, and these timing weights 16a, 16b resist the biasing force of the springs 20... when centrifugal force occurs. and expand. In addition,
Spring receivers 21, 21 which also serve as spacers are slidably inserted into the timing weights 16a, 16b, and by selecting the gap l between these spring receivers 21, 21 and the timing weights 16a, 16b, the spring 20 It is now possible to change the set load of...

Such timing weights 16a, 16b
are housed in the housing 2, and cylinder chambers 30, 30 (only one is shown) are formed in the timing weights 16a, 16b. One end of this cylinder chamber 30 opens to the outer peripheral surface between the support rods 17, 17, and the cylinder axis thereof is set in the radial direction. The other end side of the cylinder chamber 30 has an oil passage 31 extending in the direction.
are being communicated. This oil passage 31 includes, for example, a sliding surface between the timing weight 16b and the drive flange 4, and a sliding surface between the large eccentric cam 11b and the driven flange 6.
It is connected to the sliding surface etc. between the Note that the drive flange 4 also serves as one thrust receiver of the timing weight 16b. Further, another oil passage 32 extending in an oblique direction is communicated with the other end side of the cylinder chamber 30.
2 is connected to the sliding surface between the timing weight 16b and its thrust receiving plate 28. Note that 27 is a snap spring for fixing the plate 28. Furthermore, in the case of this embodiment, the oil passage 32 has a branch oil passage 33 in the middle thereof.
One end thereof is communicated with the other end thereof, and the other end thereof is communicated with a lubricating oil reservoir chamber 34 formed in the gap between the timing hub 5 and the timing weights 16a and 16b. That is, the cylinder chamber 30 and the oil passages 31, 32 are always filled with lubricating oil introduced from the lubricating oil reservoir chamber 34 through the branch oil passage 33. In addition, in FIG. 2, the small hole 5a
indicates an oil passage hole with a diameter of approximately 1 mm, and the lubricating oil is passed through the small hole 5.
The oil passes through a and is filled into the oil storage chamber 34.

A piston 35 is provided in the cylinder chamber 30.
is slidably inserted. This piston 35
extends to protrude from the cylinder chamber 30, and its protruding end 25 is in contact with the inner surface of the housing 2.

In addition, in the case of this embodiment, the piston 35
Springs 23 and 24 are bridged between the protruding end 25 of the timing weight 16b and the timing weight 16b.
22 is a spring receiving recess formed on the outer peripheral surface of the timing weight 16b.

It goes without saying that the cylinder chamber 30 on the side of the timing weight 16a has a similar configuration.

The operation of the embodiment with such a configuration will be explained.

The rotation of the engine is transmitted through gear 1 to housing 2.
and drive flange 4, large eccentric cam 1
1a, 11b, small eccentric cams 13a, 13b, and second eccentric pins 14a, 14b, the driven flange 6 is rotated. For this reason, the timing hub 5
The drive shaft 8 of the fuel injection pump is rotated through.

On the other hand, the rotation of the large eccentric cams 11a, 11b around the axes rotates the timing weights 16a, 16b via the first eccentric pins 15a, 15b. When the rotational speed of the drive flange 4 side is increased, the rotational speed of the timing weights 16a and 16b is also increased, so that the timing weight 16
The centrifugal force of a and 15b increases. Therefore, the timing weights 16a and 16b are connected to the springs 20 and 2.
Support rods 17 and 1 resist the biasing forces of 3 and 24.
7 and the thrust receiving plate 28, and are displaced in the direction of mutual expansion.

Displacement of the timing weights 16a, 16b in the outer diameter direction displaces the first eccentric pins 15a, 15b in the direction of arrow X in FIG. 3, and thus rotates the large eccentric cams 11a, 11b in the direction of arrow Y. . The rotation of the large eccentric cams 11a and 11b is caused by the rotation of the small eccentric cam 1.
3a and 13b are rotated in the direction of arrow Z with a phase difference, the rotation amount corresponding to this phase difference is the second
is transmitted to the driven flange 6 via the eccentric pins 14a and 14b. In other words, the driven flange 6 is advanced with a predetermined phase difference due to the displacement based on the centrifugal force generated in the timing weights 16a and 16b. 4, and the amount of advance θ is a value that corresponds to the rotational speed of the engine.

Note that when the rotational speed of the engine decreases, the centrifugal force decreases, so the timing weights 16a,
16b are pushed by the biasing forces of springs 20, 23, and 24, so that they are returned to the direction in which they approach each other, so that the advance angle returns to its original state.

In the above embodiment, when the timing weights 16a and 16b are expanded and displaced, the piston 35 having a diameter of about 4 to 5 mm in the cylinder chamber 30 is moved relative to the cylinder chamber 30 in the direction of compressing the lubricating oil. This allows the lubricating oil to be forcibly supplied to the sliding surfaces of each part through the cylinder chamber 30 and each oil passage 31, 32. Therefore, from this, timing weight 1
In the timing weights 6a and 16b, lubricating oil can be efficiently guided to the sliding surfaces between these and the drive flange 4 and the thrust receiving plate 28, and good sliding of the timing weights 16a and 16b can be ensured. . Therefore, it is possible to eliminate hysteresis in the timer characteristics and make the actual characteristics accurately follow the pattern of target A shown in Figure 1, which is effective in improving engine output and implementing exhaust gas countermeasures. It becomes something like that.

Also, from the cylinder chamber 30, a large eccentric cam 11b
Lubricating oil can be forcibly supplied to sliding surfaces such as the above through the oil passage 31, thereby reliably preventing seizure of each sliding surface and improving its durability. I can do it.

Furthermore, in the above embodiment, the timing weight 1
Since springs 23 and 24 are provided between 6a and 16b and the housing 2, the timer characteristics can be changed freely. In other words, the above spring 2
3 and 24 for low speed range, and support rod 17
By setting the spring 20 attached to the spring 20 for use in a high speed range, the timer characteristics can be selectively changed to a pattern such as C or D in FIG. 1, which is suitable for improving engine output and taking measures against exhaust gas.

Incidentally, the present invention can also be constructed as in another embodiment shown in FIG. That is, in this case, the driving flange 4 is connected to the engine side via the pawl 4a of the Oldham coupling ring, and the driven flange 6 is connected to the large eccentric cam 1.
1a and a small eccentric cam 13a are attached. Note that 51 and 52 indicate thrust receiving plates. A slide cylinder 56 is attached to the inner peripheral surface of the housing 2, and the piston 3
The protruding end 25 of 5 is adapted to come into sliding contact with this slide cylinder 56.

Even with this configuration, not only can the same operation as in the embodiments shown in FIGS. 2 and 3 be achieved, but also the frictional resistance between the piston 35 and the housing 2 can be reduced, so that the timer characteristics can be improved. This has the effect of further preventing hysteresis.

Furthermore, in the other embodiment shown in FIG. 6, the balls 60 are held in a holder 61, and a sliding cylinder 62 is rotatably fitted to the inner peripheral surface of the holder 61. The piston 35 is attached to the inner peripheral surface of the housing 2.
is brought into contact with the sliding cylinder 62, and this also reduces the frictional resistance between the piston 35 and the housing 2.

As detailed above, in the present invention, a cylinder chamber is formed within the timing weight, and a piston is provided in this cylinder chamber to push out the lubricating oil inside by the expansion displacement of the timing weight. Lubricating oil can be forcibly supplied to the sliding surface of the timing weight. Therefore, the sliding of the timing weight is ensured well, and the hysteresis of the timer characteristics can be reduced, which is excellent in terms of improving engine output and taking measures against exhaust gas. Moreover, the effects are great, such as being able to reliably prevent seizure and the like on each sliding surface and improve its durability.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing timer characteristics, Figs. 2 and 3 show an embodiment of the present invention, Fig. 2 is a sectional view taken along the line - in Fig. 3, and Fig. 3 is a partially sectional view. The side view shown in FIG. 4, and FIG. 5 are sectional views showing other embodiments. 2...Housing, 4...Drive flange, 5...
...Timing hub, 6...Driver flange, 11
a, 11b...large eccentric cam, 13a, 13b...
Small eccentric cam, 14a, 14b...second eccentric pin, 15a, 15...b first eccentric pin, 16
a, 16b...Timing weight, 17...Support rod, 20, 23, 24, 55...Other springs, 28, 51...Thrust receiving plate,
30... Cylinder chamber, 31, 32... Oil passage, 3
3... Branch oil path, 35... Piston.

Claims (1)

[Claim for Utility Model Registration] The rotation of the drive flange driven by the engine is transmitted to a pair of timing weights, and these timing weights are subjected to centrifugal force by a support rod against the force of a spring attached to the support rod. As a result, the timing weights are guided to expand in the radial direction, and the expansion displacement of these timing weights is transmitted to the large eccentric cam via the first eccentric pin. The movement of the small eccentric cam is transmitted to the timing hub connected to the drive shaft of the fuel injection pump through a second eccentric pin, thereby causing a relative angular displacement between the drive flange and the timing hub. In the fuel injection timing adjustment device, a cylinder chamber into which lubricating oil is guided is formed in the timing weight, and the cylinder chamber and the sliding surface of the timing weight are connected via a lubricating oil passage, and the cylinder chamber is connected to the sliding surface of the timing weight. A fuel injection timing adjustment device for an internal combustion engine, characterized in that a piston is provided in a chamber to press lubricating oil in a cylinder chamber by being slid by the expansion displacement of a timing weight.