JPS648177B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection timing adjustment device for an internal combustion engine using a hydraulic actuator.

[Prior Art] A rotating body connected to an engine and a rotating body connected to a fuel injection pump are connected by an eccentric cam mechanism having advance angle characteristics or retard single advance angle characteristics, and the eccentric cam mechanism is operated by centrifugal force. In the known fuel injection timing adjustment device, the injection timing is uniquely determined by the relationship between the engine rotation speed and the weight lift based on centrifugal force, and it is not possible to obtain an arbitrary injection timing at an arbitrary engine rotation speed.

As disclosed in Japanese Unexamined Patent Publication No. 55-5493, the hydraulic pressure of a hydraulic actuator that drives an eccentric cam mechanism is controlled by the output of an electronic control device that receives engine speed, engine load, etc. as input. In a hydraulic fuel injection timing adjustment device that obtains a predetermined injection timing at an engine rotational speed of , centrifugal force acts on the piston of the hydraulic actuator as the engine rotates, which has an adverse effect on the hydraulic control characteristics.

A prototype with a spring that counteracts the centrifugal force of the piston has been produced, but this means that if sufficient output hydraulic pressure is not obtained in the low speed range of the engine, the spring force will act as resistance and the eccentric cam mechanism will not operate. be.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the purpose of the present invention is to eliminate the influence of centrifugal force acting on the piston of a hydraulic actuator, and to use only the hydraulic pressure of the hydraulic actuator, which is sufficient even in a low speed range. An object of the present invention is to obtain a fuel injection timing adjustment device capable of controlling injection timing.

[Means for Solving the Problems] In order to achieve the above object, the present invention has a configuration in which a cup-shaped rotating body coupled to one of the engine and the fuel injection pump has a disc-shaped rotary body coupled to the other. The first rotary body is arranged concentrically and is controlled by a hydraulic actuator housed inside the disc-shaped rotary body.
A cup-shaped rotating body is connected to a disk-shaped rotating body using an eccentric cam mechanism, in which a balance weight is slidably supported on a shaft orthogonal to the hydraulic actuator, and a balance weight is slidably supported inside the disk-shaped rotating body. The cup-shaped rotating body is connected to the balance weight by the second eccentric cam mechanism accommodated in the hydraulic actuator, and the first and second eccentric cam mechanisms are configured symmetrically with respect to a diametrical line inclined at 45 degrees with respect to the central axis of the hydraulic actuator. It is something.

[Function] As the engine speed increases, the centrifugal force acting on the piston 7 increases, but this centrifugal force is offset by the second eccentric cam mechanism 45. In other words, the balance weight 31 having substantially the same mass as the piston 7 moves radially outward against the force of the return spring 33 due to centrifugal force.

The pin 46 of the second eccentric cam mechanism 45 is pushed radially outward by the counterweight 31, and the pin 46
Move around 3 in the direction of arrow Z.

Arm dc and arm cb rotate together around center c,
The eccentric cam 44 approaches the axis O side, the pin 48 is pushed to the left by the arm cb, and the central angle β between the eccentric cam 43 and the pin 48 with respect to the axis O becomes smaller.
retard.

The centrifugal force of the piston 7 causes the first eccentric cam mechanism 15
The force that tries to decrease the central angle α of the equilibrium weight 3
As a result, the first eccentric cam mechanism 15 is canceled by the centrifugal force of the hydraulic actuator 20 .
controlled solely by the hydraulic pressure supplied to the

[Embodiments of the Invention] As shown in FIGS. 1 and 2, the fuel injection timing adjustment device includes a cup-shaped rotating body 5, a disc-shaped rotating body 2 housed inside the rotating body 5, and a A pair of first eccentric cam mechanisms 15 and a pair of hydraulic actuators 2
0, a balance weight 31, and a pair of second eccentric cam mechanisms 45.

A hollow main shaft 10 integral with the rotating body 2 is connected to a shaft 32 of a fuel injection pump. The rotating body 5 is the main shaft 1
0, and is connected to an engine (not shown).

The first eccentric cam mechanism 15, which is symmetrical with respect to the main shaft 10 (axis O), is configured as follows. As shown in FIG. 1, a pair of holes 3a are provided in the rotating body 2 symmetrically with respect to the main shaft 10 (axis center O), and each hole 3a
Eccentric cam 3 is rotatably fitted to. On the other hand, the eccentric cam 4 is rotatably fitted into the eccentric hole 4a formed in the eccentric cam 3. The eccentric cam 3 is connected at an eccentric position to a piston 7 of a hydraulic actuator 20 by an eccentric pin 6, and the eccentric cam 4 is connected at an eccentric position to a rotating body 5 by an eccentric pin 8. Therefore, the driving force of the rotating body 5 is generated by the pin 8, the eccentric cam 4,
3 and is transmitted to the rotating body 2.

As shown in FIGS. 1 and 2, a pair of hydraulic actuators 20 symmetrical with respect to the main shaft 10 are rotatably supported by the main shaft 10. The piston 7 fitted into each cylinder 9 defines chambers 35 and 36, and the spring 12 is accommodated in the chamber 36. The chamber 35 is connected to the inner space of the main shaft 10 through a passage 52, and is further connected to the liquid tank 4 through a passage 53 (FIG. 2) and a solenoid valve 38.
0 and is also connected to a hydraulic pump 37 via a throttle 39.

The solenoid valve 38 is intermittently driven by an electronic control device (not shown). The position of the piston 7 of the hydraulic actuator 20 is controlled by adjusting the ratio of time during which the chamber 35 is alternately connected to the hydraulic pump 37 and the liquid tank 40 (duty ratio).

The configuration of the present invention is such that a rotating body 2 is provided with a pair of second eccentric cam mechanisms 4 that are symmetrical with respect to a main shaft 10 (axis center O).
5, and each second eccentric cam mechanism is balanced by a weight 31
It is operated by centrifugal force. Specifically, in the state shown in FIG. 1 in which the piston 7 of the hydraulic actuator 20 approaches the main shaft 10, a radial line connecting the pins 6 of the pair of first eccentric cam mechanisms 15, The pins 46 of the pair of second eccentric cam mechanisms 45 and the radial line connecting the pins 46 are perpendicular to each other.

A pair of holes 43a are provided in the rotating body 2 symmetrically with respect to the main shaft 10 (axis O), and an eccentric cam 43 is rotatably fitted into each hole 43a. On the other hand, the eccentric cam 44 is rotatably fitted into an eccentric hole 44a formed in the eccentric cam 43. The eccentric cam 43 is connected at its eccentric position to the balance weight 31 by a pin 46, and the eccentric cam 44 is connected at its eccentric position to the rotating body 5 by a pin 48.

The counterweight 31 is slidably supported on a shaft 34 extending radially outward from the cylinder 9 of the hydraulic actuator 20 at right angles. A return spring 33 is interposed between the balance weight 31 and the tip of the shaft 34.

Next, the operation of the device of the present invention will be explained. The solenoid valve 38 controls the hydraulic actuator 20 by adjusting the opening/closing time ratio (duty ratio) in relation to the engine speed, engine load, etc. hydraulic pump 3
When pressure fluid is supplied from 7 to the chamber 35 of the hydraulic actuator 20, the piston 7 widens the distance between the pair of pins 6. In FIG. 3, when the center D of the pin 6 moves in the direction of the arrow y around the center C of the eccentric cam 3 in response to the rotation of the rotating body 5 in the direction of the arrow x, the arms DC and CB are integrally centered. C, the center B of the eccentric cam 4 approaches the axis O side, and the pin 8 is pushed to the right by the arm CB, and the center C of the eccentric cam 3 and the center of the pin 8 with respect to the axis O A
The central angle α formed by the engine 1 gradually becomes smaller, and the injection timing of the engine advances as shown by the line 42 in FIG.

As the engine speed increases, the centrifugal force acting on the piston 7 increases, but this centrifugal force is offset by the second eccentric cam mechanism 45. That is, when the engine speed increases, centrifugal force acts on the balance weight 31, which has almost the same mass as the piston 7, and the balance weight 3
1 moves radially outward against the force of the return spring 33. When the pin 46 of the second eccentric cam mechanism 45 is pushed radially outward by the counterweight 31, the pin 46 moves around the center c of the eccentric cam 43 in the direction of the arrow z in FIG.
The arm dc and the arm db rotate together around the center c, the center b of the eccentric cam 44 approaches the axis O side, and the pin 48 is pushed to the left by the arm cb.
Center c of eccentric cam 43 with respect to axis O and pin 48
The central angle β between the center a and the center a becomes smaller (retarded).

The centrifugal force of the balance weight 31 causes the second eccentric cam mechanism 45
The centrifugal force of the piston 7 is the force that tries to reduce (retard) the center angle β of the first eccentric cam mechanism 15.
balances the force that attempts to decrease (advance) the central angle α.

In this way, the centrifugal force of the piston 7 is canceled by the centrifugal force of the balance weight 31, so that the first eccentric cam mechanism 15 is controlled only by the hydraulic pressure supplied to the chamber 35 of the hydraulic actuator 20, and the second eccentric cam mechanism 15 is controlled only by the hydraulic pressure supplied to the chamber 35 of the hydraulic actuator 20. Mechanism 45 follows first eccentric cam mechanism 15 .

In addition, in the above embodiment, even if the disc-shaped rotating body 2 is connected to the engine and the cup-shaped rotating body 5 is connected to the fuel injection pump, the same effect can be obtained by reversing the rotation direction. .

[Effects of the Invention] As described above, the present invention concentrically arranges a cup-shaped rotating body connected to one of the engine and the fuel injection pump, and a disk-shaped rotating body connected to the other. A cup-shaped rotating body is connected to a disc-shaped rotating body by a first eccentric cam mechanism controlled by a hydraulic actuator housed inside the disc-shaped rotating body, and an axis perpendicular to the hydraulic actuator. A counterbalanced weight is slidably supported by the counterweight, and a cup-shaped rotating body is connected to the counterbalanced weight by a second eccentric cam mechanism housed inside a disk-shaped rotating body, and the first and second eccentric cam mechanisms are connected to each other. is the center axis of the hydraulic actuator and 45
Since the configuration is symmetrical with respect to the diametrical line inclined at an angle of 100 degrees, the centrifugal force generated in the piston of the hydraulic actuator exerts a force to advance the first eccentric cam mechanism in the high-speed range of the engine, whereas the balance weight The centrifugal force generated in the second eccentric cam mechanism exerts a force to retard the second eccentric cam mechanism. As a result, the centrifugal force of the piston of the hydraulic actuator is canceled out, and the fuel injection timing is controlled only by the hydraulic pressure applied to the hydraulic actuator, greatly improving the control characteristics of the electronic control device.

According to the present invention, with the above-described configuration, the spring load that pushes back the piston can be reduced, so the drag force is small, and the hydraulic actuator operates even in the low speed range of the engine where the hydraulic pressure of the hydraulic pump is not high enough, and the injection The timing is normally controlled.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a fuel injection timing adjustment device according to the present invention, FIG. 2 is a front sectional view of the same device, FIGS. 3 and 4 are front views explaining the operation of the device, and FIG.
The figure is a diagram illustrating the operating characteristics of the device. 2: Disc-shaped rotating body, 5: Cup-shaped rotating body,
3, 4: eccentric cam, 6, 8: pin, 7: piston, 9: cylinder, 10: main shaft, 15, 45: first and second eccentric cam mechanisms, 20: hydraulic actuator, 31: balance weight, 34: shaft, 43, 44: eccentric cam, 46, 48: pin.

Claims (1)

[Claims] 1. A disk-shaped rotating body connected to one of the engine and the fuel injection pump is concentrically arranged inside a cup-shaped rotating body connected to the other, and the liquid contained inside the disk-shaped rotating body is arranged concentrically. In a device in which a cup-shaped rotating body is connected to a disc-shaped rotating body by a first eccentric cam mechanism controlled by a hydraulic actuator, a balance weight is slidably supported on an axis orthogonal to the hydraulic actuator, and a circular The cup-shaped rotating body is connected to the balance weight by a second eccentric cam mechanism housed inside the plate-shaped rotating body, and the first and second eccentric cam mechanisms are inclined at 45 degrees with respect to the central axis of the hydraulic actuator. A fuel injection timing adjustment device characterized by being configured symmetrically with respect to a diametrical line.