JPH0441231Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to an electronic speed governor, and more specifically, to an electronic speed governor installed in a fuel injection pump of an internal combustion engine such as a diesel engine. It is something.

(Prior Art) As a conventional device of this type, a voice coil type motor consisting of a compression coil spring interposed between a covered cylindrical moving coil body and a pole magnet is used as a control rack for a fuel injection pump. By connecting and applying an electric signal related to the engine speed to the moving coil body, the control rack is positioned by balancing the elastic force of the coil spring and the electromagnetic driving force acting on the moving coil body, thereby adjusting the engine. Electronic speed governors are well known (Jikkosho).
55-31217).

In this conventional device, the movable coil body is urged upward by a compression coil spring, and the movable coil body is pulled downward against the force of the coil spring by applying current, thereby increasing the fuel consumption of the control rack. It is configured to move in the direction.

(Problem to be Solved by the Invention) According to this conventional device, the position of the fuel adjustment member is determined by the balance between the spring force and the electromagnetic force according to the supplied current. The response speed of the control when moving the fuel adjustment member in the fuel reduction direction is different from the response speed of the control when moving the fuel adjustment member in the direction of fuel reduction, and it is extremely difficult to improve the controllability of the positioning control of the fuel adjustment member. It has the problem that.

Additionally, if the coil spring breaks, the moving coil body will move downward under its own weight, increasing the amount of fuel injected and potentially causing the internal combustion engine to speed up abnormally, resulting in a lack of safety. It also has some problems.

It is therefore an object of the present invention to provide an improved electronic speed governor capable of solving the above-mentioned problems of the prior art.

(Means for Solving the Problems) A feature of the present invention for solving the above problems is that a pulse current whose direction changes between positive and negative is supplied to a voice coil type motor including a moving coil body, and the pulse current is In an electronic speed governor that applies a driving force according to an amount of current according to a duty ratio to a fuel adjustment member of a fuel injection pump, thereby moving the fuel adjustment member and adjusting the fuel injection amount, the movable A link means is provided for connecting the movable coil body and the fuel adjustment member so as to move the fuel adjustment member in the fuel decreasing direction when the coil body moves in the direction of gravity, and the link means connects the movable coil body and the fuel adjustment member so that the force due to the own weight of the movable coil body and the above The movable coil body is moved in a desired direction according to a combined force with an electromagnetic driving force according to the amount of current supplied to the movable coil body.

(Function) By adjusting the amount of current applied to the moving coil body in the positive or negative direction, taking into account the force due to the weight of the moving coil body, the moving coil body is moved in the desired direction, and the fuel adjustment member is adjusted as desired. It can be moved towards the position of When power to the movable coil body is cut off for some reason, the movable coil body moves in the direction of gravity due to its own weight, and the fuel adjustment member enters the minimum fuel injection state.

(Example) Hereinafter, the present invention will be explained in detail with reference to the illustrated example.

FIG. 1 shows a cross-sectional view of an embodiment of the present invention. In this electronic governor, a camshaft 2 of the fuel injection pump protrudes into a governor case 1 connected to a fuel injection pump (not shown), and approaches a gear-shaped magnetic body 3 pivotally attached to the camshaft 2. The rotation detection sensor 4 is fixed inside the case 1.

In addition, the fuel injection pump control rack 5
protrudes into the case 1, and a pin 6a implanted in a link 6 having an intermediate fulcrum in the case 1 is inserted into a groove 5a formed at its end and engaged. The pin 6b provided at the end of the link 6 is connected to the groove 7a of the locking member 7 fixed to the upper end of the covered cylindrical moving coil body 9 of the voice coil type electromagnetic mechanism 8.
is engaged in.

This link 6 is constructed so that when the movable coil body 9 moves in the direction of gravity, it moves the control rack 5 in the direction of decreasing fuel.

The electromagnetic mechanism 8 has a bottomed cylindrical magnetic body (yoke magnet) 10, and one magnetic pole N of a cylindrical permanent magnet 12 is abutted and fixed to the circumference of the magnetic body 10. A cylindrical magnetic body (pole magnet) 13 is brought into contact with the inner bottom of the magnetic body 10 and fixed with a bolt 14 .

An annular space 11 is provided between the permanent magnet 12 and the magnetic body 13, and depending on the amount of drive current supplied to the coil 9a of the movable coil body 9,
The magnitude of the electromagnetic driving force acting on the moving coil body 9 is adjusted.

As shown in Figure 2, this drive current is a pulse current whose conduction direction changes in both positive and negative directions around the zero level, and during one cycle there are two periods in which it flows in the positive direction and a period in which it flows in the negative direction. In other words, the duty ratio is controlled. The amount of positive and negative current applied to the coil 9a is determined by this ratio.

A spring receiver 17 is fixed to the rack 5.
A resilient coil spring 15 is interposed between the spring receiver 17 and the inner wall of the case 1. The coil spring 15
has a function of absorbing rattling in the engagement portion of the link 6 and the movable coil body 9. Therefore, this coil spring 15 has a small spring force,
The structure is such that the movable coil body 9 is not moved by this spring force.

A force due to its own weight is constantly applied to the movable coil body 9 in the direction of gravity. Therefore, when a drive current of the form shown in FIG. 2 flows through the coil 9a, the amount of current is substantially The resulting combined force of the electromagnetic driving force of the movable coil body 9 and its gravity is output as the driving force of the electromagnetic mechanism 8, and the rack 5 can be moved in either direction.

Here, the amount of current applied to the coil 9a is adjusted according to the ratio of the period in which the current flows in the positive direction and the period in which the current flows in the negative direction in one cycle of the drive current, so as to move the rack 5 to the desired position. and after moving it to the desired position,
By setting the amount of current to such a value that the rack 5 remains stationary at that position, the rack 5 can be positioned at a desired position.

In this way, the coil 9a is energized in both directions, and the movable coil body 9 is moved by the combined force of the own weight of the movable coil body 9 and the electromagnetic force acting on the movable coil body 9.
If the movable coil body 9 is moved upward or downward, the same responsiveness can be obtained regardless of whether the movable coil body 9 is moved upward or downward.

The locking member 7 is provided with a rod 19 for position detection, and a displacement detection coil 18 of the control rack 5 is attached to the outside of the case on the extension of the rod 19, and the rod 19 is installed inside the coil 18.
The end portion 19a of the control rack 5 is inserted so as to be movable forward and backward, so that the position of the control rack 5 can be detected.

According to such a configuration, the gear-shaped magnetic body 3 that is pivotally attached to the camshaft 2 generates an alternating current voltage at the rotation detection sensor 4 by rotating, and the generated alternating current voltage is a voltage at a level proportional to the engine speed. and the level is compared with a voltage representing the desired target speed. Based on this comparison result, the ratio of the period in which the drive current flows in the positive direction and the period in which it flows in the negative direction shown in FIG. 2 is controlled, and as a result, the movable coil body 9 of the electromagnetic mechanism 8 is brought to the desired position. controlled like this. The above-mentioned displacement of the movable coil body 9 allows the control rack 5 to be moved to a desired position via the link 6, so that the fuel injection amount can be obtained in accordance with the load.

Further, the displacement of the control rack 5 is detected as a change in the inductance of the coil 18 due to the movement of the rod 19 within the displacement detection coil 18, and a position detection signal corresponding to the change in the inductance of the coil 18 is a feedback signal. It is supplied to the control system as This feedback signal makes it possible to limit the so-called overspeeding of the control system, thereby preventing engine speed hunting and compensating for the speed fluctuation rate.

As mentioned above, when the movable coil body 9 moves in the direction of gravity, the fuel injection amount is reduced, so if the excitation current supplied to the movable coil body 9 becomes zero due to a failure in the control circuit, etc., the movable coil Since the movable coil body 9 moves in the direction of gravity due to the weight of the body 9, the amount of fuel injection becomes the minimum, and a sudden increase in engine speed is not caused.

Furthermore, even if the spring 15 were to break, the movable coil body 9 would be displaced downward due to its own weight, causing the control rack 5 to be displaced in the direction of decreasing fuel, causing a sudden increase in engine speed due to a device failure. without causing any unforeseen circumstances,
It is extremely safe.

(Effects of the invention) According to the invention, as described above, the movable coil body and the fuel adjustment member are connected by the link means so that the fuel adjustment member is moved in the fuel decreasing direction when the movable coil body moves in the direction of gravity. For the purpose of positioning the fuel adjustment member, the movable coil body is moved by applying a composite force of the force due to the weight of the movable coil body and the driving force according to the amount of current supplied to the movable coil body to the movable coil body. Therefore, when adjusting the energization amount and moving the fuel adjustment member in the fuel increasing direction or in the opposite direction, in the fuel decreasing direction, positioning control can be performed with the same response characteristics. The controllability can be improved.

Furthermore, the moving coil body and the fuel adjustment member are connected by a link means so that when the moving coil body moves in the direction of gravity, the fuel adjustment member moves in the direction of decreasing fuel. If the motor is stopped, the fuel adjustment member will always move in the direction of decreasing fuel due to the weight of the moving coil, and in the event of a failure in the motor drive system, it will operate to reduce the engine speed, causing the engine speed to suddenly increase. It is possible to prevent dangers such as accidents and ensure safety.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a waveform diagram of the driving current. 5...Control rack, 6...Link, 8
... Electromagnetic mechanism, 9 ... Moving coil body, 13 ... Pole magnet, 15 ... Resilient coil spring.

Claims (1)

[Scope of utility model registration request] Supplying a pulse current whose direction changes between positive and negative to a voice coil type motor including a moving coil body,
An electronic speed governor that applies a driving force according to an energization amount according to a duty ratio of the pulse current to a fuel adjustment member of a fuel injection pump, thereby moving the fuel adjustment member to adjust the fuel injection amount. , further comprising a link means for connecting the movable coil body and the fuel adjustment member so as to move the fuel adjustment member in a fuel decreasing direction when the movable coil body moves in the direction of gravity, and the self-weight of the movable coil body and an electromagnetic driving force according to the amount of current supplied to the moving coil body to move the moving coil body in a desired direction.