JPS6229641Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adjustment device that advances or retards the timing of fuel injection from a fuel injection pump depending on the operating conditions of an internal combustion engine.

In general, in fuel-injected internal combustion engines, it is necessary to adjust the fuel injection timing based on changes in engine speed, load, cooling water temperature, intake pressure, etc. In this case, the fuel injection timing is advanced.

A fuel injection pump is used for fuel injection, and normally this type of fuel injection pump uses a camshaft linked to a crankshaft to reciprocate a plunger via a tapepet, and this plunger injects fuel. It is designed to be discharged. A fuel injection timing adjustment device is interposed between the crankshaft and the fuel injection pump, and the adjustment device advances and retards the rotation of the crankshaft and transmits the rotation to the camshaft. It is known that

An example of a conventional fuel injection timing adjustment device is shown in FIG. That is, reference numeral 1 indicates a rotational drive member connected to a crankshaft or the like, and integrally includes a flange portion 2 and a sleeve portion 3. Reference numeral 4 denotes a driven shaft constituting a camshaft of a fuel pump (not shown), and a hub 5 is integrally connected to the driven shaft 4 by a key 6 and a round nut 7. A cap 8 is liquid-tightly screwed onto the end surface of the hub 5, and a pressure chamber 9 is formed inside the hub 5. A driven flange 10 is integrally formed on the hub 5, and this driven flange 10 faces the inner surface of the flange portion 2 of the rotational drive member 1, and the inner peripheral surface of the concave receiving hole 11 formed in the flange portion 2. It is rotatably fitted to the This driven flange 1
0, an eccentric pin 13 of a small eccentric body 12 as disclosed in FIG. 3, which is shown as an embodiment of the present invention, is rotatably supported. Small eccentric body 12
is a fitting hole 15 eccentrically formed in the large eccentric body 14.
The large eccentric body 14 is rotatably inserted into the large eccentric body 14.
is rotatably housed in a holding hole 17 formed eccentrically in the adjustment plate 16. Adjustment plate 16 is hub 5
A storage step 18 formed on the sleeve portion 3 of the rotational drive member 1 is rotatably attached to
The rotary drive member 1 is inserted into the rotary drive member 1 and rotated integrally with the rotary drive member 1.

Cylinders 20 are arranged on the outer periphery of the hub 5 and extend in the radial direction, and these cylinders 20...
are rotated integrally via the adjusting plate 16 and pins 28, 23. Each cylinder 20... has a piston 2
1... are fitted to be slidable in the radial direction. The inside of the cylinder 20 is communicated with a pressure chamber 9 within the hub 5 through a through hole 22 formed in the hub 5. Connecting pins 23 are protruded from the pistons 21, and the connecting pins 23 protrude toward the adjustment plate 16 through guide grooves 24 formed in the cylinders 20. 24... can be moved in the radial direction. Arms 25 are connected to the connecting pin 23. As shown in FIG. 3, support rods 26 are passed through between the arms 25, and return springs 27 are held at both ends of the support rods 26, respectively. These springs 2
7... always urges the arm 25... in the direction of approaching, so the piston 21... is connected to the connecting pin 2
It is urged toward the hub 5 side, in other words, toward the center line side, by the arms 25 connected via the arms 25. An eccentric pin 28, which is eccentrically protruded from the large eccentric body 14 described above, is rotatably connected to the arm 25.

A cover 30 is provided on the sleeve portion 3 of the rotational drive member 1.
is attached via bolts 31, and this cover 30 is fitted to a fixed flange 33 via an oil seal 32. The fixed flange 33 is fixed by bolts 34 to a fixed member 35 such as the casing of the fuel injection pump described above. 3
Reference numerals 6 and 37 indicate other oil seals, and 38 indicates an oil passage for hydraulic oil. This oil passage 38 is communicated with a hydraulic oil reservoir 41 via a pressure control valve 39 and a hydraulic pump 40 shown in FIG. The pressure control valve 39 is operated under command by a computer 42, which detects operating conditions such as the rotation speed, load, cooling water temperature, or negative pressure of the internal combustion engine, and based on this detection, the pressure control valve 39 is operated by a computer 42. Pressure control valve 3
9, and the pressure control valve 39 controls the pressure of the hydraulic fluid pumped from the hydraulic pump 40 based on this instruction. Note that 43 is a return passage, and 44 is a relief oil passage.

In the conventional adjustment device of FIG. 1 constructed as described above, the rotary drive member 1 is rotated based on the operation of the internal combustion engine. The rotation of the rotary drive member 1 causes the adjustment plate 16 to rotate together. When the adjustment plate 16 is rotated, the large eccentric body 14 accommodated in the holding hole 17 of this adjustment plate 16 revolves together with the adjustment plate 16, so that the fitting hole 15 of this large eccentric body 14 is rotated.
A small eccentric body 12 fitted therein is also revolved together, and the driven flange 10 is rotated via an eccentric pin 13 protruding from this small eccentric body 12. This driven flange 10 rotates the hub 5, so the hub 5
The driven shaft 4, which is integrally connected to the driven shaft 4, is rotated.

Therefore, when the pressure of the hydraulic oil discharged from the hydraulic pump 40 is adjusted by the pressure control valve 39 and, for example, the pressure is increased and the pressure is pumped to the oil passage 38, the oil pressure in the pressure chamber 9 becomes high. This oil pressure is through hole 2
2... increases the oil pressure in the cylinder 20....
For this reason, the pistons 21... are displaced outward. The displacement of the pistons 21 causes the arms 25 to move in the outer radial direction via the connecting pins 23. Since the eccentric pin 28 of the large eccentric body 14 is connected to the arm 25..., the arm 25...
Due to the outward displacement of the large eccentric body 14, the large eccentric body 14 is rotated in the holding hole 17 in the clockwise direction shown in FIG. 3, that is, in the direction of arrow A. Arrow A of large eccentric body 14
The rotation in the direction tends to rotate the small eccentric body 12 in the same direction. The small eccentric body 12 is housed in a fitting hole 15 formed at an eccentric position of the large eccentric body 14, and is connected to the driven flange 1 through an eccentric pin 13.
0, this small eccentric body 12 is rotated in the direction of arrow B within the fitting hole 15. As a result, the driven flange 10 is forced to rotate so as to be advanced relative to the adjustment plate 16, and the driven shaft 4 is moved relative to the rotary drive member 1 via the hub 5. is advanced. From this, the fuel injection timing is advanced in the fuel injection pump.

In addition, in order to delay the fuel injection timing, if the pressure of the hydraulic oil discharged from the pressure control valve 39 is lowered,
Since the pistons 21... are returned by the springs 27..., the large eccentric body 14 and the small eccentric body 1
2, the rotation of the driven shaft 4 is retarded relative to the rotary drive member 1.

By the way, in the conventional fuel injection timing adjustment device as described above, the rotation of the rotary drive member 1 is once transmitted to the adjustment plate 16, and the rotation of this adjustment plate 16 is transmitted via the small eccentric body 12 and the large eccentric body 14. Since the power is transmitted to the driven flange 10, the flange portion 2 of the rotary drive member 1, the driven flange 10, and the adjustment plate 16 are arranged in series along the axial direction, and therefore the axial dimension of the entire device is reduced. There was a problem that caused the problem to become large. In other words, this type of fuel injection timing adjustment device is installed between the crankshaft of the internal combustion engine and the fuel injection pump, as described above, and it is necessary to ensure a large space between the crankshaft and the pump. The situation is difficult. Therefore, it is strongly desired that the axial dimension of the device be made as small as possible.

In addition, if there is non-parallelism or axial displacement between the rotational drive member 1 and the driven shaft 4, or if there are dimensional variations in the flange portion 2, driven flange 10, adjustment plate 16, etc. due to machining, etc. The gap Δl generated between the adjustment plate 16 and the driven flange 10 varies from product to product, and the timer characteristics (rotation speed -
There is a problem that the hysteresis of the advance angle characteristics changes, resulting in the disadvantage that the characteristics are not stable. It is difficult to adjust such variations in the gap Δl in the above configuration in which the adjustment plate 16 is connected to the rotary drive member 1 so as to be rotated integrally, and even if it is possible to adjust it, it is very time consuming. There was a troublesome problem.

The present invention was developed in view of the above-mentioned circumstances, and its purpose is to reduce the axial dimension of the entire device by eliminating the use of adjustment plates, and to achieve non-parallel alignment between the axes. The purpose of this invention is to provide a fuel injection timing adjustment device for an internal combustion engine that employs a structure that allows for easy adjustments to be made for axial displacement, processing variations, etc., and that can easily eliminate variations in characteristics from product to product. .

An embodiment of the present invention will be described below with reference to FIGS. 2 to 4. Components in this embodiment that are the same in terms of structure or function as the conventional example shown in FIG.

The sleeve portion 3 of the rotary drive member 1 is formed with a housing step portion 18 into which a driven flange 10 formed integrally with the hub 5 is rotatably fitted. A holding hole 17 is formed at an eccentric position in the driven flange 10, and a large eccentric body 14 is rotatably accommodated in this holding hole 17. In other words, the large eccentric body 14 is the driven flange 10
is attached to. A small eccentric body 12 is rotatably accommodated in a fitting hole 15 eccentrically opened in the large eccentric body 14. The eccentric pin 13 of the small eccentric body 12 is directly connected to the flange portion 2 of the rotational drive member 1. Note that the eccentric pin 28 of the large eccentric body 14 is connected to the arm 2.
5 is the same as in the conventional case.

On the other hand, a cover 30 is fitted onto the inner peripheral surface of the sleeve portion 3 of the rotational drive member 1. The cover 30
has a bushing portion 5 facing the end face of the driven flange 10.
0 is integrally extended, and a minute gap Δl is formed between the tip edge of this bushing portion 50 and the driven flange 10. The cover 30 is fixed to the sleeve portion 3 via a circlip 51. And this circlip 51 and cover 30
A shim 52 of an appropriate thickness is interposed between the two. Note that an O-ring 53 is interposed between the cover 30 and the sleeve portion 3 to maintain liquid tightness.

The above configuration is the difference in this embodiment from the conventional example shown in FIG. 1, and the other configurations are the same as those shown in FIG. 1 as described above, so their explanation will be omitted.

In this embodiment, the rotation of the rotary drive member 1 is directly transmitted to the eccentric pin 13 of the small eccentric body 12, and the small eccentric body 12 and the large eccentric body 14
In order to revolve the driven flange 10, the driven flange 10 is rotated. Therefore, the driven shaft 4 is rotated via the hub 5.

Then, the computer 4
When a command signal is given from 2, the pressure control valve 39 controls the pressure of the hydraulic oil sent from the pump 40 to change the oil pressure in the pressure chamber 9. When the oil pressure in the pressure chamber 9 increases, the pistons 21 are moved radially outward, and the arms 25 are displaced via the connecting pins 23. The movement of the arms 25 causes the large eccentric body 14 to rotate in the direction of arrow A in FIG. 3 via the eccentric pin 28 of the large eccentric body 14, thereby causing the small eccentric body 12 to rotate planetarily in the direction of arrow B. As a result, the driven flange 10 is rotated. This rotation of the driven flange 10 is transmitted to the driven shaft 4 through the hub 5. That is, the driven shaft 4
is advanced relative to the rotational drive member 1.

Further, when the hydraulic pressure in the pressure chamber 9 is released, the driven shaft 4 is retarded relative to the rotary drive member 1 due to an action opposite to the above action.

In the structure of this embodiment, the large eccentric body 14 is directly housed in the driven flange 10, and the eccentric pin 13 of the small eccentric body 12 is directly connected to the flange portion 2 of the rotational drive member 1, so that the structure shown in FIG. A baffle plate 16 as shown in the prior art is not required. Therefore, the axial dimension corresponding to the plate thickness of the adjusting plate 16 can be reduced, so that the overall axial dimension can be reduced. Therefore, even if the gap between the crankshaft of the internal combustion engine and the fuel injection pump is small, the fuel injection timing adjustment device of this embodiment can be easily installed.

Furthermore, since the adjustment plate 16 is not used, the number of parts is reduced.

Furthermore, since the cover 30 is fixed to the sleeve portion 3 of the rotary drive member 1 by the circlip 51, the operability of attaching and detaching the cover 30 is improved, and internal parts can be inspected, repaired, and replaced easily. Moreover, a bushing portion 50 is integrally extended to the cover 30, and the front end surface of the bushing portion 50 and the driven flange 1
The configuration is such that a gap Δl is created between the two. This gap Δl can be adjusted by a shim 52 provided between the circlip 51 and the cover 30. The gap Δl must be adjusted when the rotary drive member 1 and the driven shaft 4 are non-parallel or axially displaced, or when there are variations in the machining of each part. The thickness can be easily adjusted by selecting the thickness. Therefore, variations in characteristics such as timer characteristics can be adjusted very easily for each product, making it possible to provide a fuel injection timing adjustment device with stable quality.

As detailed above, in the present invention, the large eccentric body is directly connected to the driven flange, and the eccentric pin of the small eccentric body is directly connected to the flange portion of the rotational drive member, so the conventional adjustment plate is not required. Therefore, the axial dimension of the entire device can be reduced, and it can be installed even in a place with a small installation space. Moreover, in the present invention, the cover is fixed to the sleeve portion of the rotary drive member via a circlip, and the driven flange is held between the cover and the drive member, so that the ease of attaching and detaching the cover is improved. Internal parts can be inspected and repaired easily. In addition, the gap between the driven flange and the driven flange, which is rotated relative to the cover, can be adjusted very easily by interposing a shim between the cover and the circlip as necessary. This has the advantage that it is possible to easily adjust the uniformity of characteristics for each product by correcting variations in timer characteristics.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional example, Figs. 2 to 4 show an embodiment of the present invention, and Fig. 2 is a sectional view;
3 is a cross-sectional view taken along the line - in FIG. 2, and FIG. 4 is a cross-sectional view taken along the line - in FIG. 3. DESCRIPTION OF SYMBOLS 1...Rotation drive member, 2...Flange part, 3...
... Sleeve part, 4 ... Driven shaft, 5 ... Hub, 1
0... Driven flange, 12... Small eccentric body, 14...
... Large eccentric body, 16 ... Adjustment plate, 20 ... Cylinder, 21 ... Piston, 25 ... Arm, 30 ...
...Cover, 50...Button section, 51...Circlip, 52...Shim.

Claims (1)

[Scope of utility model registration request] A flange portion and a sleeve portion are formed on a member to be rotationally driven, and an eccentric pin of a small eccentric body is connected to the drive flange portion, and the small eccentric body is eccentrically connected to a large eccentric body, and the large eccentric body is connected to a hub. The hub is connected to the driven shaft in a rotatable and eccentric manner to the driven flange formed in the hub, and a hydraulic piston that is slid in the radial direction based on hydraulic pressure is integrated with the hub on the outer periphery of the hub. The hydraulic piston is connected to the large eccentric body so as to transmit the sliding motion of the hydraulic piston to the large eccentric body via an eccentric pin, and a cover is fitted onto the inner circumferential surface of the sleeve portion of the rotary drive member. The cover is fixed to the sleeve portion by a circlip, and the driven flange of the hub is held between the cover and the flange portion of the driving member, and the position of the cover is adjusted by shims as necessary. 1. A fuel injection timing adjustment device for an internal combustion engine, characterized in that: