JP3894464B2 - Actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an actuator configured to hold a rotor in a predetermined position when a coil of an electronic control throttle is not energized.
[0002]
[Prior art]
The electronically controlled throttle operates on the principle that the rotor is rotated in accordance with the depression amount of the accelerator pedal, and the rotation angle of the throttle valve integrated with the rotor is controlled. In this type of electronically controlled throttle, it is necessary to ensure a minimum throttle valve opening (securing the default position) even when the electromagnetic coil is deenergized due to a failure.
[0003]
In this case, as a method for controlling the rotor to a predetermined position, various methods have been proposed in recent years in which a mechanical spring is omitted using a reaction force generated by a magnetic spring when the coil is not energized.
[0004]
This type of system includes Japanese Patent Application No. 7-56686 (A) in which reaction force is obtained by a magnetic spring, and Japanese Patent Application No. 9-56 in which reaction force is obtained by a magnetic spring and an auxiliary mechanical spring is used only near the default opening position. No. 11857 (B), and Japanese Patent Application No. 10-107, which uses three magnetic poles to prevent saturation of the magnetic path, deforms the shape of the rotor to create a space, and provides a magnet only on a part of the rotor. No. 69410 (c) has already been proposed by the present applicant.
[0005]
The prior application indicated by (c) will be described with reference to FIG. FIG. 5 shows an actuator body 1 in which a rotor 2 rotates inside a main air gap 5 with a shaft center O (not shown) as a fulcrum. The rotor 2 has a first circumferential portion 6 having a _first radius l ₁ and a second circumferential portion 7 having a _second radius l _2, and a magnet is formed on the second circumferential portion. 3-1 and 3-2 are provided. The magnet 3-1 is magnetized in the N pole and the magnet 3-2 is magnetized in the S pole.
[0006]
The rotor 2 does not occupy the entire main air gap 5, but has a deviated shape, and the magnets 3-1 and 3-2 are provided on part of the periphery. . Therefore, the main air gap 5 has a space 4 in which no rotor exists.
[0007]
As can be seen from the above configuration, the magnet 3-1 faces the magnetic pole pieces 10 and 11, and the facing portion has an N pole, and the magnet 3-2 faces the magnetic pole pieces 10 and 12 and the facing portion has an S pole. . In short, the pole piece 10 faces the two magnets, the pole piece 11 faces the magnet 3-1, and the pole piece 12 faces the magnet 3-2.
[0008]
The pole piece and the magnet are usually opposed to each other with a mechanical gap of about 0.4 mm. A coil 9 (magnetomotive force source) is wound around the coupling magnetic paths 13 and 14 from the magnetic pole piece 10 to the magnetic pole pieces 11 and 12 via the bobbin 8. The magnetic pole pieces 11 and 12 are connected by a connecting magnetic path 15. Reference numerals 19 and 20 denote magnetic gaps for accumulating energy in this portion to obtain a reaction force similar to that of a spring.
[0009]
The operation principle will be described with reference to FIG. When the coil 9 is energized, a magnetic flux as indicated by a solid line arrow is generated, and the illustrated magnetic pole is generated on the magnetic pole piece side. That is, an S pole is generated in the pole piece 11, and an attractive force is generated with the N pole of the magnet 3-1. Further, S is generated in the magnetic pole piece 12, and a repulsive force is generated with the S pole of the magnet 3-2.
[0010]
On the other hand, the pole piece 10 generates an N pole, and generates a repulsive force with the magnet 3-1 and an attractive force with the magnet 3-2. As a whole of these, the rotor 2 is rotated in the direction of the arrow A shown in the figure. Here, when the energization direction is reversed, the polarity of the pole piece is reversed, and torque in the reverse direction is generated.
[0011]
[Problems to be solved by the invention]
According to the above-described prior art, the main air gap 5 has a circular shape, and the rotor inside thereof is also symmetric. Therefore, the space 4 is also symmetric, and the electromagnetic coil 9 is not excited (current value 0). It stops at the position shown in FIG.
[0012]
However, in the electronically controlled throttle, it is necessary to secure the throttle valve opening for limp home (securing the default position) even when the coil is turned off due to failure.
[0013]
This default opening needs to be set optimally. However, in the conventional examples (a) and (c), the accuracy of the default position may be insufficient, and it is difficult to set the default position. was there. Furthermore, in the conventional example (b), the structure is complicated and expensive.
[0014]
The present invention has been made to solve the above-described problems, and provides an actuator that not only has a default position that is stable and highly accurate, but also that the default position can be easily set, has a simple structure, and is low in cost. It is aimed.
[0015]
[Means for Solving the Problems]
In the actuator according to [Claim 1] of the present invention, a rotatable rotor and at least one magnetomotive force source are integrally incorporated through a magnetic path, and the rotor is magnetized in the opposite direction. The pole and the S pole are provided integrally or separately on the peripheral edge thereof, and three magnetic pole pieces are provided on the peripheral edge of the opening in which the rotor is arranged, and the two adjacent magnetic pole pieces are respectively connected by connecting passages. In the connected electromagnetic actuator, a convex portion is provided asymmetrically on the outer periphery of the opening, and two pole pieces provided on both ends of the operating range of the rotor are excited to the same polarity by the magnetomotive force source. And the lengths of the portions facing the rotor are different from each other.
[0016]
In the actuator according to [Claim 2] of the present invention, in [Claim 1], the setting of the default position is made variable by adjusting the width and length of the convex portion to the outside of the main air gap.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing an embodiment of an actuator according to the present invention. In FIG. 1, the same parts as those of FIG. In the present embodiment, the structural feature is that a part of the main air gap is greatly enlarged and the enlarged position is shifted, and the other structure is the same as that of FIG.
[0018]
Here, the main air gap 5 reaches the B position with a radius l ₄ clockwise from the A position as a reference, and further has a radius l ₅ from the B position to the A position, and has a relationship of l ₅ > l ₄ . That is, from the B position to the A position in the clockwise direction, it has the shape of an opening whose radius is increased by l ₅ −l ₄ = Δl (this is referred to as an outward convex portion, and the opening increased thereby. Part is called the expansion gap).
[0019]
Further, the rotor 2 reaches the B position with a radius l ₂ clockwise from the A position, and further decreases from the B position to the A position with a radius l ₁ and has a relationship of l ₂ > l ₁ (ie, This is referred to as an inward recess). Reference numeral 3-1 denotes a magnet magnetized to the N pole, and 3-2 denotes a magnet magnetized to the S pole, which are fixed to the peripheral surface of the rotor 2. Each radius in the figure has a relationship of l ₅ > l ₄ > l ₃ > l ₂ > l ₁ .
[0020]
In addition, the enlarged gap is not symmetrical, but is asymmetric (shift) with respect to a center line (not shown) passing through the point O. For example, as shown in FIG. It is configured. This means that the length of the portion facing the magnet 3-1 (N pole) is large on the pole piece 11 side, and the length of the portion facing the magnet 3-2 (S pole) is small on the pole piece 12 side. It means that.
[0021]
Reference numeral 9 denotes an electromagnetic coil as a magnetomotive force source, which is wound through a bobbin 8. 10, 11, and 12 are magnetic pole pieces, a part of the magnet 3-1 and a part of the magnet 3-2 are opposed to the magnetic pole piece 10, a part of the magnet 3-1 is opposed to the magnetic pole piece 11, A part of the magnet 3-2 is opposed to the pole piece 12. Reference numerals 13, 14, and 15 denote coupled magnetic paths.
[0022]
The operation will be described with reference to FIG. First, when the current of the electromagnetic coil 9 is 0 (when the coil is not energized) , the magnetic flux from the N pole of the magnet directly reaches the S pole in the magnetic pole piece 10, and the magnetic flux from the magnet N pole is connected in the magnetic pole piece 11. together leading to magnet S pole facing the pole piece 12 through the magnetic path 15, also the magnetic flux from the N pole of the pole piece 11 reaches the S pole of the pole piece 10 through the connecting magnetic path 13.
[0023]
In this state, since the main air gap interval is the smallest at l ₄ -l ₃ on both magnet sides, the rotor is stopped at the illustrated position. In this case, since the convex portion 16 to the outside of the main air gap and the concave portion 17 to the inside of the rotor 2 are aligned at the A position and the B position, the opening area 18 is the largest (as described above) A thing enlarged by the convex part which spreads outside is called an expansion gap.) As for the magnetic pole pieces, the two magnetic pole pieces 11 and 12 provided on both ends of the operating range of the rotor 2 have different lengths facing the rotor as described above. That is, the 11 side is long and the 12 side is short.
[0024]
When the coil 9 is energized, a magnetic flux as shown by a solid line arrow in FIG. 1C is generated, and the illustrated magnetic pole is generated on each magnetic pole piece side. That is, an S pole is generated in the pole piece 11, and an attractive force is generated with the N pole of the magnet 3-1. In addition, an S pole is generated in the pole piece 12, and a repulsive force is generated with the S pole of the magnet 3-2. Further, the N pole is generated in the magnetic pole piece 10, and the attractive force is generated with the S pole of the magnet 3-2. As a whole, the rotor 2 is rotated in the direction of the arrow A in the figure. Here, when the energization direction is reversed, the polarity of the pole piece is reversed, and torque in the reverse direction is generated.
[0025]
Next, let us consider a case where the current value becomes 0 due to a failure from the state in which a predetermined value of current flows through the electromagnetic coil 9. In this case, since the magnetomotive force source by the electromagnetic coil 9 has disappeared, only the magnetomotive force source of the magnet by the rotor 2 is obtained.
[0026]
Accordingly, the rotor 2 that is at a predetermined angle corresponding to the current value returns in the direction of the dotted arrow, but stops at this position when the end of the magnet 3-2 of the rotor coincides with the B position. The reason for this is that if the magnet 3-2 of the rotor 2 continues to rotate right beyond the B position as described above, the magnet 3-2 provided on the rotor and the convex portion to the outside of the main air gap This is because the width of the air gap between them increases, and the magnetic resistance (reluctance) increases.
[0027]
According to the present embodiment, the reluctance can be changed by adjusting the width of the convex part to the outside and the total length of the convex part, and the default position of the rotor can be determined with high accuracy.
[0028]
FIG. 2 is a block diagram showing another embodiment. In FIG. 2, the same functional parts as those in FIG. 2 is characterized in that magnetic gaps 19 and 20 are provided in the connecting passages 13 and 14, and the other features are the same as those in FIG.
[0029]
Next, the operation will be described. When a current flows through the electromagnetic coil 9, the magnetic energy generated by the magnetic flux from the electromagnetic coil is accumulated in the two magnetic gaps 19 and 20 and the enlarged gap 18. Therefore, when the current of the electromagnetic coil becomes 0, the magnetic spring works so as to minimize the stored magnetic energy and returns to the position shown in FIG. 2 and stops. The stop position is as described above.
[0030]
According to the present embodiment, when the electromagnetic coil is not energized, the rotor is returned to a predetermined position by the magnetic spring. At this time, the rotor stops before the enlarged gap position, so that the accuracy of the default position is improved. Further, since the magnet is provided on a part of the circumferential surface of the rotor, the amount of use is small and the cost is low.
[0031]
FIG. 3 is a block diagram showing still another embodiment. In FIG. 3, the same functional parts as those in FIG. The structural feature of FIG. 3 with respect to FIG. 1 is that a magnetic gap 21 is provided at the connecting portion between the pole piece 10 and the coupling magnetic paths 13 and 14. The reason why the magnetic gap is provided is that magnetic energy is accumulated in this portion in the same manner as described above, and the same effect as the spring is added. According to the present embodiment, the same effect as in FIG. 2 can be obtained.
[0032]
FIG. 4 is a block diagram showing still another embodiment. In FIG. 4, the same functional parts as those in FIG. The feature of the structure of FIG. 4 with respect to FIG. 2 is that the convex portion to the outside of the main air gap is made stepwise. According to the present embodiment, the default position of the rotor can be determined with high accuracy by adjusting the width and length of each step of the convex portion to the outside.
[0033]
【The invention's effect】
As described above, according to the present invention, the number of the magnetic pole pieces is three, the magnetic pole pieces are connected by the connecting passages, and the width and length of the convex portion to the outside of the main air gap are adjusted. In addition to being stable and highly accurate in the default position, it is possible to provide a low-cost actuator in which the default position can be easily set.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of an actuator according to the present invention.
FIG. 2 is a configuration diagram showing another embodiment.
FIG. 3 is a configuration diagram showing still another embodiment.
FIG. 4 is a configuration diagram showing still another embodiment.
FIG. 5 is a diagram illustrating a conventional technique.
FIG. 6 is a diagram for explaining the operation of the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Actuator main body 2 Rotor 3-1 and 3-2 Magnet 4 Space 5 Main air gap 6 1st circumference part 7 2nd circumference part 8 Bobbin 9 Electromagnetic coil 10-12 Magnetic pole pieces 13-15 Connection magnetic path 16 Convex part 17 Outside Concave part 18 Opening area 19-21 Magnetic gap

Claims (2)

A rotatable rotor and at least one magnetomotive force source are integrated with each other through a magnetic path, and the rotor has an N pole and an S pole magnetized in opposite directions as an integral or separate magnet. In the electromagnetic actuator in which three magnetic pole pieces are provided on the peripheral edge of the opening where the rotor is disposed and two adjacent magnetic pole pieces are connected to each other by a connecting passage. The two pole pieces provided on both ends of the operating range of the rotor are asymmetrically provided with convex portions outward , and the length of the portion facing the rotor is excited to the same pole by the magnetomotive force source. Actuators characterized by different from each other.   2. The actuator according to claim 1, wherein the setting of the default position is made variable by adjusting the width and length of the convex portion to the outside of the main air gap.

Images