JP2002147211A - Electromagnet actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnet actuator decreasing magnetic resistance even in the position far from an electromagnet and holding an armature at low holding current in seating of the armature. SOLUTION: This actuator has the armature connected to the valve and supported in the neutral position in a non-operating state; and first and second electromagnets facing each other through the armature, and driving the armature between the closing position and the opening position of the valve. The outer circumferential parts of yokes of the first and second electromagnets are connected with extended yoke parts, the end of the armature is faced to the end surface of the yoke in a state that the armature is seated on the first or second electromagnet, and a gap is present between the side edge part of the armature and the extended yoke. Even when the armature is in the position far from each electromagnet by the extended yoke part in the outer circumferential part, magnetic resistance is low, and since the end of the armature is faced to the end surface of the yoke in seating of the armature, the armature is held at low holding current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator mechanism for an electromagnetic valve, and more particularly, to an electromagnetic actuator for driving various valves in an engine mounted on an automobile, a ship or the like.

[0002]

2. Description of the Related Art An actuator that drives an intake / exhaust valve in an engine of an automobile or the like electromagnetically instead of a conventional mechanical drive is generally called an electromagnet type actuator. Such an electromagnet type actuator can precisely control the driving timing and driving force by controlling an electric signal, and is highly needed in a field where precise timing control and variable control are desired.

[0003] An armature (ar) sandwiched between a pair of opposing springs is provided between one end and the other end by alternately supplying power to an electromagnet to one of such electromagnet type actuators.
mature). The valve is connected to the armature by a valve shaft, and opens and closes in response to movement of the armature.

An electromagnet type actuator is a so-called EI.
It has a yoke, an armature, and a coil called a mold. The coil and the yoke constitute an electromagnet, and generate a magnetic flux according to the magnitude of the current flowing through the coil. The armature is attracted to the electromagnet according to the magnitude of the magnetic flux along the driving direction, and performs a desired driving operation. Typically,
The direction and magnitude of the magnetic flux linking the armature depends on the configuration and shape of the yoke, the armature, and the coil. Further, at the time of driving the armature, the distance between the armature and the yoke in the driving direction changes, so that the direction and the magnitude of the magnetic flux linking the armature also change complicatedly according to the distance.

Therefore, in order to drive the armature efficiently, the configuration and shape of the yoke, the armature, and the coil must be such that the magnitude of the magnetic flux linking the armature becomes as large as possible at any armature position. It is desirable to take.

FIG. 1 is a sectional view of a conventional electromagnet type actuator. The electromagnet type actuator 11 includes a valve 13, a valve shaft 15, an armature 17, an open spring 19, a closed spring 21, a closed yoke 23, and an open yoke 2.
5, a closed coil 27 and an open coil 29. The valve 13 is connected to the armature 17 by a valve shaft 15 and can open and close according to the movement of the armature 17. The open-side coil 29 surrounded by the open-side yoke 25 and the closed-side coil 27 surrounded by the closed-side yoke 23 can be supplied with current by any electric control means to generate magnetic flux. When current does not flow through both coils (that is, when no magnetic flux is generated), the armature 17 is given an offset load by a pair of springs including an open-side spring 19 and a closed-side spring 21, and the closed yoke 23 And the open side yoke 25 is held at a neutral position.

When a current is applied to one coil to generate a magnetic flux that overcomes the repulsive force of a pair of springs, the armature 1
7 is seated on the yoke by its magnetic attraction. For a suitable period of time, a constant current is supplied to the coil and the armature 17
Is released from the seated state when the current supply is stopped. When released from the seated state, the armature 17 starts moving toward the other yoke due to the potential energy of the spring. At this time, an appropriate current is supplied to the other coil in accordance with the displacement of the armature 17, and a magnetic attraction force that attracts the armature 17 to the other yoke is generated.

FIG. 2 is a schematic diagram showing the state of magnetic flux depending on the position of the armature 17 in the conventional electromagnet type actuator 11. In this figure, for convenience, a spring,
The valve and the valve shaft are not shown. Here, the magnetic flux is indicated by 31, and the direction of the attraction force when the armature is seated is indicated by 33. In this figure, a current is passed through a lower coil to generate a magnetic flux 31 for seating the armature 17 on a lower electromagnet. FIG. 2A shows a case where the armature 17 is separated from the seating yoke (the lower yoke in the figure), and FIG. 2B shows a case where the armature 17 is seated on the seating yoke. Indicates when

In the case of FIG. 2A, that is, the armature 1
When the armature 7 is apart from the seating side yoke, the air gap between the armature 17 and the seating side yoke is large, and the magnetic resistance passing through the armature 17 and the seating side yoke has a large magnetic resistance. And a large amount of magnetic flux 31 leaks into the space. Therefore, the magnetic attraction for attracting the armature 17 to the yoke is small. On the other hand, FIG.
In other words, when the armature 17 is seated on the yoke, the air gap becomes sufficiently small and the magnetic resistance rapidly decreases, so that the magnetic flux 31 rapidly increases. Thereby, the magnetic attraction force is also increased as compared with the case where the armature 17 is separated.

With respect to the increase in the magnetic resistance when the distance between the armature 17 and the yoke is large as described above,
A structure has been proposed in which the magnetic resistance is made smaller than before by changing the shape of the yoke. FIG. 3 shows a simple sectional view of an electromagnet type actuator 35 using such a structure. This figure also shows a state in which a current is passed through a lower coil to generate a magnetic flux 31. (A) of FIG.
FIG. 3B shows a case where the armature 17 is separated from the seating-side yoke (the lower yoke in the drawing), and FIG. 3B shows a case where the armature 17 is seated on the seating-side yoke.

As compared with the yoke of the actuator 11 shown in FIG. 2, the yoke on the closed side and the yoke on the open side of the actuator 35 shown in FIG. By adopting such a structure, a magnetic circuit is formed by a small gap between the continuous yoke 37 and the side edge portion 39 of the armature, and the magnetic resistance is reduced even when the armature 17 is separated from the seating side yoke. can do.

In the case of FIG. 3A, that is, the armature 1
When the armature 7 is away from the seating yoke, the magnetic circuit is formed by a small gap between the yoke 37 and the side edge 39 of the armature, so that the magnetic resistance is reduced and more lines of magnetic force link the armature 17. Intersect. Therefore, the magnetic resistance when the armature 17 is separated from the seat side yoke decreases,
The magnitude of the magnetic flux 31 linking the armature 17 increases.

[0013]

However, in such a prior art structure, the ratio of the vertical component of the magnetic attractive force is reduced, so that the attractive force for attracting the armature 17 does not increase. Further, the armature 17 has a yoke 37
In the seated state, the center of the armature 17 is completely seated on the seating surface 41 of the inner yoke, but since there is a gap between the continuous yoke 37 and the side edge 39 of the armature, the magnetic resistance is reduced. It cannot be made small enough.
Also, between the continuous yoke 37 and the side edge 39 of the armature, the magnetic attraction acts in the horizontal direction, and
It does not act as a suction force to draw the downward. Therefore, in order to generate a sufficient holding force downward, a relatively large current must be passed.

Accordingly, the present invention provides an electromagnet type actuator which can reduce the magnetic resistance when driving the electromagnet and can hold the armature with a small holding current when seated even when the armature is at a position away from the yoke. The purpose is to:

[0015]

In order to solve the above problems, an electromagnet type actuator according to the present invention faces an armature connected to a valve and supported at a neutral position in a non-operating state, with the armature interposed therebetween. First and second driving the armature between a closed position and an open position of the valve.
An electromagnet-type actuator comprising: an electromagnet; and a yoke of the first and second electromagnets has an outer peripheral portion connected by an extension yoke portion, and the armature is seated on the first or second electromagnet. In this state, the end of the armature faces the end surface of the yoke, and a gap exists between the side edge of the armature and the extension yoke.

According to the present invention, since the first and second yokes are connected by the extension yoke portion at the outer peripheral portion, the electromagnet drive can be performed even when the armature is at a position away from the first or second electromagnet. When the armature is seated, the armature faces the end face of the yoke, so that a vertical attractive force can be efficiently generated, and the armature can be held with a small holding current. it can.

[0017]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 4 is a sectional view schematically showing an electromagnet type actuator 43 according to the present invention. In this figure, a spring, a valve, and a valve shaft are not shown for convenience, but are the same as those shown in FIG. 1 except for the structure of the yoke 45.

Electromagnet type actuator 4 according to the present invention
The yoke 45 has an outer peripheral wall and an inner peripheral wall surrounding the coil at upper and lower sides, and the upper and lower outer peripheral parts are at the extension yoke part 4.
7 is connected. The coils are arranged above and below the yoke 45 between the inner peripheral portion and the outer peripheral portion, respectively.
And the second electromagnet 51. These electromagnets can be supplied with current by, for example, any electric control means as shown in FIG. 5 to generate a magnetic flux for driving the armature 17. If no current is flowing through both coils (ie, no magnetic flux is generated),
The armature 17 is given an offset load by a pair of springs, and is held at a predetermined neutral position.

The armature 17 includes a first electromagnet 49 and a second electromagnet 49.
Between the side edge 39 of the armature and the extension yoke 47 at any armature position. In this embodiment, the size of the gap is about 0.1 mm. Further, the armature 17 is the first or second electromagnet 4
9 and 51, the end 54 of the armature faces the yoke end face 52 of the outer periphery, and the gap between the end 54 of the armature and the end face 52 of the yoke is the side edge 39 of the armature.
And the extension yoke portion 47 is made smaller than the gap. In this embodiment, the size of the gap is about 0.02.
mm.

FIG. 4 shows the state of magnetic flux in the operation of the electromagnet type actuator 43 according to the present invention. Also in this figure, as in the case of FIGS. 2 and 3, a current is passed through the lower coil to generate a magnetic flux 31 for seating the armature on the lower yoke. FIG. 4A shows a case where the armature 17 is separated from a seat-side yoke (the lower yoke in the figure), and FIG. 4B shows a case where the armature 17 is seated on the seat-side yoke. Is shown.

When the armature 17 is sufficiently separated from the seat-side yoke as shown in FIG. 4A, the gap between the extension yoke portion 47 and the side edge portion 39 of the armature is formed with the end surface 52 of the yoke. It is small compared to the air gap between the end 54 of the armature. Therefore, a relatively large magnetic flux flows through the gap between the extension yoke portion 47 and the side edge portion 39 of the armature. This is the electromagnet type actuator 35 shown in FIG.
And the effect of lowering the magnetic resistance of the armature 17 at a position distant from the seat-side yoke.

When the armature 17 is seated on the yoke as shown in FIG. 4B, the gap between the yoke end face 52 and the armature end 54 becomes extremely small due to the downward movement of the armature 17. However, the distraction yoke 4
Since the size of the gap between the armature 7 and the armature side edge 39 does not change, this gap is relatively large as compared with the gap between the yoke end face 52 and the armature end 54. As a result, the flow of the magnetic flux does not pass through the gap between the extension yoke portion 47 and the armature side edge portion 39, but passes between the yoke end surface 52 and the armature end portion 54 having a smaller magnetic resistance.
At this time, the magnetic attraction force acting on the armature 17 is greater than that of the electromagnet type actuator 35 shown in FIG. 3 because the force acting on the yoke end face 52 acts as a vertical force. Therefore, the electromagnet type actuator 43 according to the present invention includes the armature end portion 54 and the yoke end surface 52.
When the distance is large, the magnetic resistance can be reduced, and at the same time, the electromagnetic energy required to generate a holding force at the time of sitting can be reduced, so that the current flowing through the coil can be reduced.

FIG. 5 shows an overall configuration example of a control device 53 used in the electromagnet type actuator 43 according to the present invention. The control unit 53 includes an arithmetic unit (CPU) 55, a read-only memory (ROM) 57 for storing control programs and data, and a random access memory (RAM) for temporarily storing data and providing an arithmetic work area for the CPU.
59 and an input / output interface 61.

The electromagnet 71 indicates the first electromagnet 49 or the second electromagnet 51 formed by each coil of the electromagnet type actuator. PWM (pulse width modulation)
The driver 65 performs pulse width modulation on the voltage supplied from the constant voltage power supply 63 according to a control signal from the control device 53 and supplies the voltage to the electromagnet 71. The voltage supplied to the electromagnet 71 is detected by the voltage detector 67, and the current is supplied to the current detector 6
9 is detected. The constant voltage power supply 63 boosts a voltage, such as 12 V, provided from a vehicle-mounted battery to, for example, 30 V
This is a power supply that supplies a constant voltage of 100 V to 100 V.

The input / output interface 6 of the control device 53
1, a voltage detection signal from the voltage detector 67, a current detection signal from the current detector 69, and any other signals are input. From these inputs, ROM5
In accordance with the control program stored in 7, the control device 53 determines parameters such as the timing of power supply, the magnitude of the supplied voltage, and the time of supplying the voltage. A control signal corresponding to the determined parameter is sent to the PWM driver 65 via the input / output interface 61 of the control device 53 to control the electromagnet type actuator.

The controller 53 controls the electromagnet 71 at a predetermined constant voltage until the armature is seated at the other end.
When power is supplied to the armature and the armature is held at the other end,
The PWM driver 65 is controlled so as to supply electric power to the electromagnet 71 with a constant current. Such a control method enables a driving operation for stably seating the armature.

FIGS. 6 to 8 show the transition of each parameter in the driving operation of the conventional electromagnet type actuators 11 and 35 and the electromagnetism type actuator 43 according to the present invention. With reference to these figures, advantages of the actuator according to the present invention will be described.

FIG. 6 shows the transition of each parameter in the driving operation of the conventional electromagnet type actuator 11 shown in FIG. 2, and FIG. 7 shows the transition of each parameter in the prior art actuator 35 having a continuous yoke shown in FIG. 8 shows the transition of each parameter of the driving operation of the actuator 43 according to the embodiment of the present invention shown in FIG. The driving operation of each actuator is controlled so that about 3.5 ms after the armature 17 is released from one seating surface, the armature 17 is seated on the other seating surface, and the armature 17 is held on the other seating surface until 5 ms.

In each of these figures, an actuator having a laminated E-type yoke made of a silicon steel plate and a single-plate armature was used. The x-axis indicates time in units of ms, and the state where the armature is completely seated on one seating surface is defined as 0 ms. The y-axis is illustrated corresponding to each of the curves (ae).

In each of the figures, the curve a shows the displacement of the armature from one seating surface. The amount of movement that the armature can move between the opposing electromagnet is about 7
mm. Curve b shows the electric energy input to the electromagnet. This energy indicates the transition of the electric energy supplied to the coil, and is related to the amount of power consumed when the actuator is driven. A curve c indicates the magnitude of the vertical attractive force generated by the electromagnet. Here, the force required to hold the armature is about 300N. In each actuator, a corresponding current must be supplied to the coil to hold the armature. In this embodiment, the holding current is, for example, PWM.
A constant current is supplied using the driver 65. Curve d
Indicates a current flowing through the coil. Curve e shows the voltage supplied between the terminals of the coil constituting the electromagnet.

The gap between the yoke and the armature side edge 39 in the actuator 35 having the continuous yoke shown in FIG. 7 and the actuator 43 of the present invention shown in FIG. 8 is 0.1 mm. Further, the gap between the end surface of the yoke and the end of the armature when the armature 17 is seated is all 0.02 mm.

Referring to FIG. 6, the details of the driving operation of the actuator 11 having the divided yokes will be described.

1) The initial state of the armature at 0 ms is a state where the armature is seated on one yoke. The current holding the armature is supplied to one coil, and the armature is completely stationary at one yoke. At this time, no current flows through the other coil, and therefore, there is no attractive force for attracting the armature to the other yoke.

2) Simultaneously with stopping the current holding the armature in one yoke, the armature is released from the seated state,
The time in the figure begins to elapse. The armature loses the holding force on one yoke and starts moving toward the other yoke by the potential energy of the pair of opposing springs. Immediately after the armature is released, until the armature position passes the neutral position, no current is still supplied to the other coil, and the armature moves only by the driving force due to the potential energy of the spring.

3) At a certain point in time when the position of the armature has passed the neutral position, ie, in the case of FIG. 6, about 2.5 ms has elapsed, a current flows due to the supply of a constant voltage to the other coil and a magnetic flux. Is generated, and an attractive force for attracting the armature to the other coil is generated. At this time, since the distance between the end of the armature and the end surface of the yoke is large, the magnetic flux flowing through the armature is small, and the attraction force is also small. After about 3 ms, the current supplied to the coil reaches a peak, but the magnetic attraction continues to increase.

4) After about 3.5 ms, the armature sits on the other yoke. At this point, the control of the electromagnet is switched from the constant voltage drive to the constant current drive, the holding current flowing through the coil holds the armature in the yoke, and the magnetic attraction force becomes approximately 3
It is kept constant at 00N.

An armature driving operation step similar to that shown in FIG. 6 was performed for each actuator in FIGS. 7 and 8, and the current and electric energy required for the operation were compared for each actuator. According to FIGS. 6, 7, and 8, the total amount of energy input to the electromagnet by 5 ms is 0.29 J, 0.42 J, and 0.24 J, respectively. It shows the lowest power consumption. The reason why the actuator 35 having the continuous yoke (FIG. 4) requires a large amount of energy as compared with the others is that the energy (current) required for holding the armature at the time of sitting is large as compared with the others. As described above, the force acting between the continuous yoke and the armature side edge 39 is a force acting in the horizontal direction. This force does not act as a suction force for pulling the armature down when the armature is to be held on the seating surface, but is merely a loss. Therefore, when trying to generate an attractive force that holds the armature with an electromagnet,
Requires more current than others, resulting in higher input energy.

The reason why the actuator 11 having the divided yokes shown in FIG. 6 requires a larger input energy than the actuator 43 of the present invention becomes clear from the difference in the current peak value around about 3 ms. The current peak of the actuator 11 having a divided yoke is about 9 A, whereas the actuator 43 having an end face at the extension yoke portion is provided.
Is about 7 A, and the current required to hold the armature is approximately the same, so that the input energy of the actuator 43 of the present invention is relatively small.

Such an actuator 4 according to the present invention
The small input energy at 3 makes it possible to reduce the power consumption compared to the actuators 11, 35 in the prior art. In particular, when the engine speed is low, the power consumption characteristic when the armature is held has a great effect. Therefore, the low power consumption when the armature is held in the actuator according to the present invention is very useful. Further, the reduction in the current peak characteristic can reduce the requirements for components such as switching elements used in the drive circuit, and can realize cost reduction.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to such embodiments.

[0041]

According to the electromagnet type actuator of the present invention, even when the armature is located at a position distant from the first or second electromagnet, the magnetic resistance when driving the electromagnet is relatively small, and when the armature is seated, Can be efficiently generated, and the armature can be held with a small holding current.

[Brief description of the drawings]

FIG. 1 shows a sectional view of a prior art yoke-separated electromagnetic actuator.

FIG. 2 is a diagram showing a change in magnetic flux according to an armature position in the actuator of FIG. 1;

FIG. 3 is a diagram showing a change in magnetic flux depending on an armature position in a conventional electromagnetic actuator having a continuous yoke.

FIG. 4 shows a sectional view of an electromagnetic actuator according to the invention.

FIG. 5 shows an overall block diagram of an actuator control device according to an embodiment of the present invention.

FIG. 6 shows parameters in a driving operation of a conventional electromagnetic actuator having a divided yoke.

FIG. 7 shows parameters in a driving operation of an electromagnetic actuator having a continuous yoke according to the related art.

FIG. 8 shows parameters in a driving operation of the electromagnetic actuator according to the present invention.

[Description of Reference Numerals] 17 armature 43 electromagnet type actuator 45 yoke 47 extension yoke part 49 first electromagnet 51 second electromagnet 52 end face of yoke

Continued on front page F term (reference) 3G018 AB09 CA12 DA39 DA41 DA83 FA01 FA06 FA07 GA14 GA18 GA37 3H106 DA07 DA25 DB02 DB12 DB26 DB32 DC02 EE16 GA13 KK17 5E048 AB01 AD02 5H633 BB07 BB10 GG02 GG04 GG09 GG13 HH05 JA05 JA02

Claims (1)

[Claims] An armature connected to a valve and supported at a neutral position in a non-operating state, a first armature facing the armature across the armature, and driving the armature between a closed position and an open position of the valve; And a second electromagnet, wherein a yoke of the first and second electromagnets has an outer peripheral portion connected by an extension yoke portion, and the armature is connected to the first electromagnet.
Alternatively, in a state where the armature is seated on the second electromagnet, the end of the armature faces the end surface of the yoke, and a gap exists between a side edge of the armature and the extension yoke.
Electromagnet type actuator.