JPH0449839A - Dual-direction drive rotary actuator - Google Patents

Abstract

PURPOSE:To drive a rotating shaft bidirectionally by generating torque in different rotating directions to a movable iron core by generating a magnetic flux to a couple of gaps wherein the circumferencial surfaces of involute curves of movable iron core and stationary iron core are provided opposed with each other. CONSTITUTION:A rotor 3 is provided with a movable iron core 6 at the center of a rotating shaft 2, and the movable iron core 6 has a basic circle concentric with the rotating shaft 2 and is provided with a pair of involute end surfaces 7a, 7b in which the expanded diameter direction for the same basic circle is composed of the opposite involute curves. Moreover, the involute end surfaces 17, 17 of the stationary iron core 11 are symmetry with respect to the axial center of the rotating axis 2 with the relation of right and left mirror image of the involute line. A current is alternately applied to a pair of coils 14, 14 of the stationary iron core 11. Thereby, the rotor 3 is driven in the dual- direction. At the time of drive, a gap 18 changes in the equal direction for the entire part of the opposed surface without relation to a rotating angle of the rotor 3.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an electromagnetic rotary actuator in which rotational force is directly generated on the output shaft, and in particular, the gap surface on which the electromagnetic action acts is shaped like an involute curve. This invention relates to a bidirectional output rotary actuator formed by

[Prior Art] Regarding an electromagnetic rotary actuator in which the gap surface on which electromagnetic action acts is formed by an involute curve, the present applicant has proposed Japanese Patent Application No. 1-338650.
I have already applied.

FIG. 3 is a longitudinal sectional view showing an example of the rotary actuator.

The rotary actuator (01) has a fixed iron core (03) (
03), and a stator (05) consisting of a coil (04) also fixed to the center of the inner peripheral surface of the case (02);
A lid member (07) that closes both end surfaces of the case (02) (
The yoke shaft (09) is firmly fitted to the pivoted rotating shaft (06) by the bearings (08) (08) at the center of the yoke shaft (07), and the yoke shaft (09) The rotor (011) is formed by fitting and fixing movable iron cores (010) (010) to the rotor (011).

The case (02) also serves as a yoke member for magnetically coupling the fixed core (03) (03), and also serves as a yoke member for magnetically coupling the fixed core (03).
The cylindrical spacer (012) sandwiched between (03) also serves as a yoke member.

Case (02), spacer (012) and yoke shaft (0
9) is made of a ferromagnetic material such as soft iron.

The fixed core (03) and the movable core (010) are made by punching a ferromagnetic plate material such as a silicon steel plate into the shape shown in FIG.

In the state shown in Fig. 4, the fixed core (03) and the movable core (
010) Sky 1 between! There is no space in Jl (013), and the two are in close contact. The boundary surface on the fixed core (03) side at this time is the inner peripheral surface (03a), and the movable core (010)
The boundary surface on the side is defined as the outer circumferential surface (010a).

This boundary surface, that is, a void with a gap size of zero (0
13) is an involute curve consisting of a base circle (014) concentric with the axis (0) of the rotating shaft (06).

The inner circumferential surface (03a) of the fixed core (03) made of an involute curve is equal to the movable range of the movable core (010),
It is a squid or slightly larger.

The inner peripheral surface (03a) of the fixed core (03) and the movable core (03)
The surfaces facing the outer circumferential surface (010a) of 10) always face each other with involute curves that make the base circles (014) equal.

As a result, a gap (013) between the fixed core (03) and the fixed core (03) caused by the rotation of the movable core (010) is formed between the inner circumferential surface (03a) of the fixed core (03) and the movable core (OJO).
) The size (gap) of the void (013) is always uniform at any position where the outer circumferential surface (010a) of the spacer (010a) faces each other.

In other words, the inner peripheral surface (03a) of the fixed iron core (03),
When the surface facing the outer peripheral surface (010a) of the movable core (010) is formed by an involute curve, the movable core (010)
) Regardless of the rotation angle of the
Efficiently generate rotational torque.

[Problems to be Solved by the Invention] In the conventional rotary actuator described above, the direction in which the rotational force acts is constant, and a spring force is usually applied in the direction in which the gap between the electromagnets widens.

In addition, when driving force is required in both directions, a pair of rotary actuators of the same structure are used with the output rotation directions opposite to each other and the output shafts connected in series.

However, when a spring is used for return, an extra drive output is required for the return force of the spring, and in order to hold the position at the end of the suction position, the drive power must be sustained or a locking mechanism must be used. Is required.

If a pair are used in opposite directions, the axial dimension will be too large, making it difficult to downsize.

[Means for Solving the Problems] In the present invention, the above problems are solved as follows.

In a rotary actuator in which the gap between a fixed core and a movable core in an electromagnet is formed by an involute curve having a base circle concentric with the rotation axis of the movable core, the directions of diameter expansion with respect to the same base circle are opposite to each other. A movable iron core that has a pair of circumferential surfaces made of involute curves in the same direction, and an involute curve that faces the circumferential surfaces made of a pair of involute curves in the movable core, and the opposing ones have the same base circle and the same radial expansion direction. The end face consisting of 1
When one of the end faces of the involute curves of the movable core and the fixed core facing each other is in contact with each other,
The relative positions of the end faces of the movable core and the fixed core are determined so that there is a gap between the end faces of the other involute curve, and each of the movable core and the fixed core At least two coils are wound around a fixed iron core to generate magnetic flux in two air gaps where the circumferential surfaces of the involute curves face each other, and the magnetic flux generated by each coil is always kept constant. It is characterized by comprising an intermediate magnetic path forming yoke member that forms a magnetic path for connecting to the movable iron core with a resistor.

Moreover, the movable iron core is characterized in that it is a permanent magnet whose circumferential surfaces of a pair of involute curves serve as dual pairs of magnetic poles.

[Operation] Torques in different rotational directions are generated in one movable iron core to drive the rotating shaft in both directions.

If the movable iron core is made of a permanent magnet, the direction of rotation can be selected depending on the current direction of the excitation coil. Furthermore, at the stop position of the movable core, the free rotation of the movable core is locked by the magnetic force of the permanent magnet.

[Example Figures 1 and 2 show an example of the present invention.
This will be explained below based on the drawings.

The rotary actuator (1) has a rotating shaft (2
), a stator (4) provided around the axis so as to surround the rotor (3), and a case (5) that houses the rotor (3) and the stator (4). ing.

The rotor (3) has a movable iron core (6
), and the movable iron core (6) has a cross-sectional shape in the direction orthogonal to the axis, as shown in Fig. It is provided with a pair of involute end surfaces (7a) and (7b) each having a base circle (the path shown in the figure) and consisting of involute curves whose diameter expansion directions relative to the same base circle are opposite to each other.

Between the involute end surfaces (7a) and (7b), there is an arc surface (8) with a reduced diameter and an equal radius.
a) A stopper (9) is provided at the arc surface (8) between the small diameter stepped portion (10) (10) of (7b).

The stopper (9) comes into contact with the small-diameter stepped portion (10) to restrict the rotation range of the rotor (3).

The lower end of the stopper (9) is connected to the bottom surface (5a) of the case (5).
) is fixed.

As shown in Fig. 2, the stator (4) is constructed by fitting a coil (14) wound around a winding frame (13) into the central core leg (12) of an E-type fixed core (11). A pair of identical shapes are symmetrical (mirror image relationship) across the axis of rotation (2).
Assemble by butting the outer core legs (15) and (16) together.

The inner end of the central core leg (12) of the E-type fixed core (11) has an involute end surface (
7a) An involute end face (17) is formed having the same involute curve as (7b).

The fixed core (1) assembled as this stator (4)
The involute end faces (17) (17) of 1) have involute curves that are symmetrical in a mirror image relationship left and right about the axis of the rotating shaft (2), and the involute end faces (17) of the movable iron core (6) in the rotor (3) are symmetrical. It is aligned with the end faces (7a) and (7b).

The case (5) housing the stator (4) is made of a ferromagnetic material such as soft iron, and is made of a ferromagnetic material such as soft iron.
14) It can also be used as a yoke member to compensate for the lack of cross-sectional area in (15) or to form a magnetic path in place of the outer core legs (4) and (15).

Involute end face (7a) (7b) of rotor (3)
and the involute end face (17) (+7
) are opposed to the rotor (3) and stator (4).
An air gap (18) is formed between them in which electromagnetic action occurs.

The outer peripheral surface of the fixed core (11) in the stator (4) is
It is provided in close contact with the inner surface of the case (5), and this case (
The center of the bottom surface (5a) of the rotor (3) is located at the center of the bottom (5a) of the rotor (3).
2) Although it rotates, it is magnetically coupled to the lower surface of the enlarged diameter step portion (2a) provided below, with a small magnetic resistance.

The upper part of the enlarged diameter step part (2a) is magnetically coupled to the center of the lower surface of the movable iron core (6). As a result, the central part (6a) of the movable core (6) has a magnetic pole opposite to the involute end surface (17) of the fixed core (11), that is, the outer core legs (15) (16) of the E-type fixed core (11). , and magnetically coupled to the magnetically equivalent part.

In FIG. 2, the rotor (3) shown by the solid line has an air gap (1) between the involute end surface (17) of the left fixed core (11) and the involute end surface (7a) of the movable core (6).
8) is in close contact with zero. In this case, the involute end surface (7b) of the right side movable core (6) changes from the state in which it is in close contact with the involute end surface (17) of the fixed core (11). , the rotor (3) is rotated counterclockwise by an angle corresponding to the required output rotation angle to create a gap (18) of the required size between both involute end faces (7b) (17). .

The position of the rotor (3) shown by the solid line is the starting position when driving clockwise.

Further, the rotor (3) shown in phantom line is at the start position when driven counterclockwise.

To drive the rotor (3), current is passed through the coil (14) of the fixed iron core (11) on the side where the air gap (18) is open.

The rotor (3) is driven bidirectionally by passing current through the pair of coils (14) (14) alternately.

During this drive, the size of the gap (18) formed by an involute curve having the same base circle is the same over the entire opposing surface, regardless of the rotation angle of the rotor (3). Changes with distance. That is, even if the size of the gap (18) changes, the distance between the opposing surfaces of the involute end faces (7a) and (17) and (7b) and (17) that form the gap (18) changes in parallel. .

As a result, the magnetic flux distribution in the air gap (18) is averaged no matter what rotation angle the rotor (3) is at.

The rotary actuator (1) shown in FIGS. 1 and 2 above uses a permanent magnet as the movable core (6) of the rotor (3), so that bidirectional drive can be achieved in the same way as in the above embodiment, and another We can provide you with something that works and works.

Note that the structure is exactly the same as in FIGS. 1 and 2, so illustration is omitted.

The magnetization direction of the movable iron core (6) is such that the pair of involute end faces (7a) (7b) are aligned with S, which is the dual of the magnetic poles.
Make it a pole and a north pole.

When driving the rotor (3), each corresponding coil (1
4), select the excitation current direction of both coils (14) (
14), a current is applied at the same time.

As a result, the movable iron core (6) of the rotor (3) receives rotational force in the same direction from both involute end faces (7a) (7b), and the rotating shaft (2) generates a well-balanced moment.

Furthermore, when the rotor (3) is stopped at one of the stable positions, the poles of the permanent magnets in the movable core (6) with zero air gap (18) are magnetically attached to the fixed core (11). ,
Lock the free rotation of the rotor (3).

This locking effect is exerted when the rotor (3) stops rotating in both directions, and since the force for this locking effect is obtained from a permanent magnet, it is powerless and permanent.

[Effects of the Invention] Torques in different rotational directions are generated in one movable iron core to drive the rotating shaft in both directions.

The stator (4) has a coil (1
4), which have the same structure and are fitted, are used in symmetrical combination in a mirror image relationship, so the structure is simple and assembly is easy.

Rotor (3) and stator (4) forming a gap (1g)
By adopting an involute curve on each end face of the iron core, the air gap (1
8) Efficiently generate rotational torque by averaging the magnetic flux distribution on the surface.

If the movable core is made of a permanent magnet, the direction of rotation can be selected by the current direction of the excitation coil, so regardless of the direction of rotation,
A pair of coils can be used for excitation at the same time, increasing coil utilization efficiency.

Further, the movable iron core is prevented from freely rotating at both stable positions by the magnetic attraction force of the permanent magnet.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention. FIG. 1 is a central vertical sectional view of the rotary actuator of the present invention, FIG. 2 is a cross-sectional plan view taken along line U-U in FIG. 1, and FIG. FIG. 4 is a central longitudinal sectional view of a conventional rotary actuator by the present applicant. FIG. 4 is a plan view transverse to the rV-mV line in FIG. 3. (18) Gap (1) Rotary actuator (2) Rotating shaft (2a) Expanded diameter step (3) Rotor (4) Stator (5) Case
(6) Movable iron core (6a) central part (7a)
(7b) Involute end face (8) Arc face
(9) Stopper (10) Small diameter stepped portion (5
a) Bottom surface (11) E-type fixed core (12) Center core leg (13) Winding frame (14) Coil (
15) (16) Outer core leg (17) Involute end face Figure 1 Figure 3 Figure 4

Claims (2)

[Claims] (1) In a rotary actuator in which the gap between the fixed core and the movable core of the electromagnet is formed by an involute curve having a base circle concentric with the rotation axis of the movable core, the direction of diameter expansion with respect to the same base circle is , a movable core that has a pair of circumferential surfaces made of involute curves in opposite directions, and a movable core that faces a circumferential surface made of a pair of involute curves in the movable core. When a movable core and a fixed core have a pair of end faces consisting of involute curves, and one of the end faces of the involute curves of the facing movable core and the fixed core is in contact with each other, there is a gap between the facing portions of the end faces of the other involute curve. A fixed core in which the relative positions of the end faces of the movable core and the fixed core having involute curves are determined, and gaps in two locations where the circumferential surfaces of the involute curves of the movable core and the fixed core face each other. At least two coils are wound around a fixed core so as to generate magnetic flux, and a magnetic path is formed to connect the magnetic flux generated by each coil to the movable core at a constant magnetic resistance. A bidirectional drive rotary actuator comprising: an intermediate magnetic path forming yoke member. (2) The bidirectional drive rotary actuator according to claim (1), wherein the movable iron core is a permanent magnet whose circumferential surfaces of a pair of involute curves are dual pairs of magnetic poles.