JP7381964B2 - actuator - Google Patents

Description

The present invention relates to an actuator, and particularly to an actuator that can actively move a shaft in both directions.

In a typical actuator that uses a coil and a movable core, the movable core must be at a distance that can be attracted by the coil, so it is difficult to achieve a large stroke of the shaft.

In contrast, a so-called step feed configuration has been proposed, in which the shaft is advanced little by little to obtain a large moving distance by repeating engagement and disengagement with the shaft in accordance with the movement of the movable iron core. Patent Document 1 describes a first locking mechanism that locks when the shaft is sent by the movable core, a second locking mechanism that locks the shaft so that it does not return when the movable core returns, and the first and second locking mechanisms. An actuator is described that includes a release mechanism for releasing the lock.

Patent Document 2 discloses a reciprocating drive source that reciprocates first and second engaging members (members having a forward inclined surface and a reverse inclined surface) in directions in which they approach and separate from each other; A configuration is disclosed that includes first and second wedge engagement mechanisms that are incorporated between a mating member and a shaft and control engagement or release of a wedge member (roller). A magnetostrictive element and a coil are used to move the engaging members toward and away from each other. The wedge engagement mechanism includes coil assemblies placed at both ends of the actuator to control engagement and release by causing the roller to hit or avoid hitting the inclined surface.

Patent No. 6610843 Patent No. 4294701

However, in the configuration of Patent Document 1, when the shaft is sent, the shaft is fed gradually, but when the shaft is returned, the first and second locking mechanisms are released at once. Although this configuration is excellent in that the shaft can be instantly returned to its initial position, it is likely to generate impact noise. If a shock absorbing material, a damper mechanism, etc. are provided, there is a problem that the actuator will become larger and the cost will increase. Furthermore, if the stroke of the shaft is increased by using a coil spring to return the shaft, there is a problem in that the device becomes larger.

Although the configuration of Patent Document 2 is said to have a smaller inertial resistance than a motor drive such as a worm gear, there is a problem that the movement speed of the actuator is slow because the amount of distortion of the magnetostrictive element is extremely small. Further, since coil assembly is required at both ends of the actuator as the first and second wedge engagement mechanisms, there is a problem that the device tends to be larger and the cost increases.

An object of the present invention is to provide an actuator that can actively move a shaft in both directions without increasing the size of the device or increasing cost.

In order to solve the above problems, a typical configuration of an actuator according to the present invention includes two electromagnetic parts arranged to face each other with respect to a shaft, and each electromagnetic part includes a coil, a movable core, A locking mechanism is provided between the movable core and the shaft, and the locking mechanism engages the shaft when the coil is energized and the movable core moves, and when the coil is de-energized and the movable core is moved. It is characterized in that it does not engage with the shaft in the return direction, but when the coil is de-energized and the movable core is in the initial position, the movable core of the other electromagnetic section engages with the shaft in the return direction.

According to the above configuration, if one of the two electromagnetic parts arranged oppositely is driven so as to be energized and the other not to be energized, the energized one will send out the shaft, and the non-excited one will cause the shaft to return. to regulate. Therefore, it is possible to actively move the shaft in both directions.

The locking mechanism includes a rolling element that rolls on a shaft to form a wedge, and an engagement member that is fixed to a movable core and has two inwardly inclined surfaces with which the rolling elements abut. When the movable iron core's initial position side is referred to as the original inclined surface, and the side on which the movable iron core is excited and moves is referred to as the forward inclined surface, the actuator is further arranged within the movable iron core and the rolling element is placed on the original side. It has an internal elastic body that biases the inclined surface, and an external elastic body that is placed outside the movable core and biases the rolling element toward the tip inclined surface when the coil is de-energized. It is preferable that the urging force of the external elastic body is larger.

According to the above configuration, when the movable core is in the initial position when not energized, the rolling element is urged toward the forward inclined surface, so that the shaft engages in the direction in which it moves toward the other electromagnetic part. It functions reliably as a one-way clutch. Then, when the coil is excited and the movable core moves slightly, and the biasing force of the external elastic body weakens, the movable core and the shaft can be engaged and the shaft can be sent out. That is, it becomes possible to switch the engagement direction of the lock mechanism depending on the position of the movable iron core.

It includes a fixed core placed between the coil and the movable core, a stopper that the movable core comes into contact with when the coil is de-energized, and a permanent magnet placed on the opposite side of the stopper to the movable core. There is a magnetic gap between the magnet and a member other than the movable core, and when the coil is not energized and the movable core and the stopper are in close contact, a first magnetic path is formed from the permanent magnet to the movable core; When the coil is excited and a second magnetic path is formed from the coil to the movable core, the first magnetic path is switched from the permanent magnet to a third magnetic path that passes through the magnetic gap and does not pass through the movable core. is preferred.

According to the above configuration, the movable iron core at the initial position is attracted by the permanent magnet. Therefore, when an external force is applied to the shaft, the attraction force of the permanent magnet is obtained in addition to the biasing force of the return spring, so that movement of the movable core due to the external force can be suppressed.

According to the present invention, it is possible to provide an actuator that can actively move a shaft in both directions without increasing the size of the device or increasing cost.

FIG. 1 is an overall configuration diagram of an actuator according to the present embodiment. It is a figure explaining a lock mechanism. It is a figure explaining operation of a lock mechanism. It is a figure explaining operation of a lock mechanism. FIG. 6 is a diagram illustrating a case where a large external force is applied to the shaft. It is a figure explaining operation of magnetic path switching. It is a figure explaining other embodiments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely illustrative to facilitate understanding of the invention, and do not limit the invention unless otherwise specified. In this specification and the drawings, elements with substantially the same functions and configurations are given the same reference numerals to omit redundant explanation, and elements not directly related to the present invention are omitted from illustration. do.

FIG. 1 is an overall configuration diagram of an actuator according to this embodiment, and shows a state in which two electromagnetic parts are both de-energized. There is no distinction between left and right in the actuator 100 according to this embodiment, and when the words "left and right" are used in the following description, they simply mean left and right in the drawings.

In the actuator 100, a yoke 104 is arranged at the center of a housing 102, and two electromagnetic parts (a first electromagnetic part 106a and a second electromagnetic part 106b) are arranged on the left and right sides of the yoke 104. The central yoke 104 is shared by the electromagnetic parts 106a and 106b. The electromagnetic parts 106a and 106b are arranged to face each other, and the arrangement and operating directions of a movable core 210 and locking mechanisms 300a and 300b, which will be described later, are also reversed.

Since the electromagnetic parts 106a and 106b have the same structure, the structure of the first electromagnetic part 106a will be explained as a representative. If it is necessary to call the left and right parts separately, a branch number a is added to the reference numeral for the members of the first electromagnetic section 106a, and a branch number b is added to the reference numeral for the members of the second electromagnetic section 106b.

The first electromagnetic section 106a includes a coil 200 arranged to wind around the shaft 10, a movable core 210, and a fixed core 204 disposed between the coil 200 and the movable core 210. The fixed iron core 204 and the movable iron core 210 are both cylindrical magnetic bodies, and are arranged inside the coil 200 in the radial direction.

A return spring 212 is arranged inside the central yoke 104 to urge the movable core 210 to the initial position. When the coil 200 is excited, magnetic flux passes through the movable core 210, so the movable core 210 moves against the biasing force of the return spring 212. When the coil 200 is de-energized, the movable core 210 is pushed by the return spring 212 and returns to the initial position, and comes into contact with the stopper 214.

FIG. 2 is a diagram illustrating the lock mechanism 300a. A lock mechanism 300a is provided between the movable core 210 and the shaft 10. The locking mechanism 300a includes two or more rolling elements 302 (rollers) that roll on the shaft 10 to form a wedge, a retainer 304 that maintains the posture of the rolling elements 302, and an engagement member fixed to the movable iron core 210. and a member 310.

The engagement member 310 is a ring-shaped member fitted inside the movable core 210, and has a recess formed on the inner surface to accommodate the rolling element 302. The recess has two inwardly sloping surfaces. Of the two inwardly facing inclined surfaces, the initial position side (movement source side) of the movable core 210 is referred to as a source side inclined surface 314, and the side where the movable iron core 210 is excited and moves (movement destination side) is referred to as a forward side inclined surface 312. to be called. When the rolling element 302 comes into contact with the forward inclined surface 312 or the original inclined surface 314 and is sandwiched between it and the shaft 10, it functions as a wedge and engages them.

The movable iron core 210 is provided with an internal elastic body 216 that urges the rolling elements 302 toward the original inclined surface 314 via the retainer 304. The internal elastic body 216 can be composed of, for example, a coil spring. Also, provided outside the movable iron core 210 is an external elastic body 218 that urges the rolling element 302 toward the front inclined surface 312 when the coil 200 is not energized and is in the initial position. Since the external elastic body 218 requires a short stroke, it can be constructed of a disc spring, for example. The biasing force of the external elastic body 218 is set larger than the biasing force of the internal elastic body 216.

With the above configuration, when the coil 200 is de-energized (when the movable core 210 is in contact with the stopper 214), the shaft 10 is engaged (restricted) in the direction of movement toward the second electromagnetic section 106b. Functions as a one-way clutch. That is, the lock mechanisms 300a and 300b engage with the shaft 10 in the direction in which the movable core 210 of the other electromagnetic section returns. In particular, since the external elastic body 218 urges the rolling element 302 toward the forward inclined surface 312, the engagement can function reliably. The white arrow in the figure indicates that the shaft 10 is movable relative to the locking mechanism 300a, and the direction in which the white arrow is crossed indicates that it is not movable relative to the lock mechanism 300a. .

Then, as shown in FIG. 1, since the first electromagnetic part 106a and the second electromagnetic part 106b are arranged facing each other, the locking mechanisms 300a and 300b both move inward (toward the other electromagnetic part) when they are not energized. The movement of the shaft 10 in the direction toward which the shaft is directed is restricted. Therefore, movement of the shaft 10 is locked when no action is being taken, without the need for power or control.

3 and 4 are diagrams for explaining the operation of the locking mechanism. In FIG. 3A, the movable core 210 is at the initial position, and the locking mechanism 300a is engaged in the direction in which the shaft 10 moves, as described above. Conversely, it does not engage in the direction in which the shaft 10 moves from the second electromagnetic section 106b toward the first electromagnetic section 106a. That is, the shaft 10 cannot be moved in the feeding direction (rightward in the figure).

However, as shown in FIG. 3(b), when the coil 200 is excited and the movable core 210 moves slightly, the stroke of the external elastic body 218 is no longer reachable, so its biasing force weakens, and the biasing force of the internal elastic body 216 becomes smaller. becomes larger. Then, the internal elastic body 216 urges the rolling element 302 toward the original inclined surface 314 via the retainer 304. Therefore, the locking mechanism 300a engages with the shaft 10 in the direction in which the movable core 210 moves.

That is, as shown in FIG. 3(c), the direction of engagement of the locking mechanism 300a can be switched depending on the position of the movable core 210. The switching position is a position where the biasing forces of the internal elastic body 216 and the external elastic body 218 are balanced. As a result, a simple structure can be achieved without using a coil part assembly for controlling engagement and release as in Patent Document 2 (prior art), and the actuator can be made smaller and less expensive. can.

As shown in FIG. 4(a), when the coil 200 is excited and the movable core 210 is moved, the locking mechanism 300a of the first electromagnetic section 106a is engaged, and the locking mechanism 300b of the second electromagnetic section 106b is engaged. It doesn't match. Thereby, the shaft 10 can be sent as the movable core 210 moves toward the second electromagnetic section 106b.

When the coil 200 is de-energized as shown in FIG. 4(b), the locking mechanism 300a does not engage in the return direction of the movable core 210 of the first electromagnetic section 106a. The locking mechanism 300b of the second electromagnetic section 106b engages with the shaft 10 in the direction in which the movable core 210 of the first electromagnetic section 106a returns because the coil 200 is de-energized and the movable core 210 is at the initial position. This allows the shaft 10 to remain in the position it was sent to. Therefore, by repeating energization and de-excitation of the coil 200 of the first electromagnetic section 106a, it is possible to gradually feed the shaft 10 in the right direction in the figure, in a stepwise manner.

What is important about the present invention is that among the two electromagnetic parts 106a and 106b arranged opposite to each other, the one that repeats energization/de-energization sends out the shaft, and the one that maintains de-excitation restricts the return of the shaft. It is. This makes it possible to actively move the shaft 10 in both directions. Therefore, unlike Patent Document 1 (prior art), the shaft 10 does not return to the initial position all at once, so there is no need for a structure for shock mitigation, and there is no need to increase the size according to the stroke of the shaft, resulting in a smaller actuator. This makes it possible to reduce the cost.

FIG. 5 is a diagram illustrating a case where a large external force F acts on the shaft 10. As described above, both lock mechanisms 300a and 300b restrict movement of the shaft 10 inward when not energized. Therefore, movement of the shaft 10 is locked, but when a strong external force F acts on the shaft 10, the movable core 210 may move.

For example, when an external force F is applied from the left side of the shaft 10 as shown in FIG. 5, the locking mechanism 300a of the first electromagnetic section 106a is engaged, but the locking mechanism 300b of the second electromagnetic section 106b is not engaged. . At this time, the urging force of the return spring 212 resists the external force F, but since the return spring 212 cannot be made stronger than the attraction force of the coil 200, it is difficult to increase the holding force (fixing force) of the shaft 10 with the return spring 212 alone. is difficult.

Therefore, in this embodiment, a permanent magnet and a magnetic path switching structure are used to suppress the movement of the movable core 210 and increase the holding force of the shaft 10.

As shown in FIG. 5, the actuator 100 further includes a permanent magnet 220 disposed on the opposite side of the stopper 214 from the movable core 210, and a cover 230 that contacts the fixed core 204 and covers the outside of the permanent magnet 220. A narrow magnetic gap G is formed between the stopper 214 and the cover 230. That is, the stopper 214 has a magnetic gap G between the permanent magnet 220 and members other than the movable iron core 210.

FIG. 6 is a diagram illustrating the operation of magnetic path switching. As shown in FIG. 6A, when the coil 200 is de-energized and the movable core 210 and the stopper 214 are in close contact, the first A magnetic path R1 is formed.

On the other hand, as shown in FIG. 6(b), when the coil 200 is excited and a second magnetic path R2 passing from the coil 200 through the yoke 104, the movable core 210, and the fixed core 204 is formed, the second magnetic path R2 is formed. The path of magnetic path R2 is magnetically saturated. In particular, when the common path of the first magnetic path R1 and the second magnetic path R2 (the position surrounded by the broken line ellipse) becomes saturated, it becomes difficult for the magnetic flux emitted from the permanent magnet 220 to pass through this path. Therefore, the path of the magnetic flux emitted from the permanent magnet 220 is switched to the third magnetic path R3 passing from the permanent magnet 220 to the stopper 214, the magnetic gap G, and the cover 230. Since the third magnetic path R3 does not pass through the movable core 210, it does not affect the attraction force of the movable core 210 by the coil 200.

According to the above configuration, since the first magnetic path R1 passes through the movable core 210, the permanent magnet 220 attracts the movable core 210 at the initial position. Therefore, when an external force F is applied to the shaft 10 when the coil 200 is de-energized, the attraction force of the permanent magnet 220 is obtained in addition to the urging force of the return spring 212, so that the movement of the movable core 210 due to the external force F is prevented. This can increase the holding force of the shaft 10 when the shaft 10 is stopped.

FIG. 7 is a diagram illustrating another embodiment, and is an overall configuration diagram and a partially enlarged diagram. In the actuator 100A shown in FIG. 7, compared to the actuator 100 shown in FIG. 1, the operating direction of the movable core 210 is reversed.

In the actuator 100A shown in FIG. 7, two electromagnetic parts (a first electromagnetic part 108a and a second electromagnetic part 108b) are arranged on the left and right sides. The electromagnetic parts 108a and 108b are arranged to face each other, and the arrangement and operating directions of the movable core 210 and the lock mechanisms 300a and 300b are also reversed.

A recess 12 is formed in the middle of the shaft 10 and is partially tapered. On the other hand, the yoke 332 attached to the center of the housing 330 has a narrow width corresponding to the recess 12. Thereby, the stroke of the shaft 10 can be regulated (the range of movement can be regulated), and the shaft 10 can be prevented from falling off. Further, by sufficiently moving the shaft 10 to either the left or right side, the position can be initialized by control.

Furthermore, in the configuration of FIG. 1, the fixed core 204 is separate from the housing 102 from the viewpoint of assembly. However, by adopting a structure in which the electromagnetic portion is reversed as in the configuration shown in FIG. 7, the fixed core 320 and the housing 330 can be integrated, and the number of parts can be reduced.

Since the electromagnetic parts 108a and 108b have the same structure, the first electromagnetic part 108a is partially enlarged as a representative.

Referring to the partially enlarged view, when coil 200 is excited, movable iron core 210 is attracted and moves toward the left side (outside the device) in the figure. Then, in the locking mechanism 300a, the rolling elements 302 come into contact with the base inclined surface 314 and are sandwiched between them and the shaft 10, thereby functioning as a wedge and engaging them. The shaft 10 is then sent to the left in the figure. At this time, in the second electromagnetic section 108b, since the retainer 304 of the rolling element 302 is urged by the external elastic body 218, the rolling element 302 is urged against the front side inclined surface 312, so that the shaft 10 This does not prevent it from being sent to the left in the figure.

When the coil 200 is de-energized, the movable core 210 is returned to its initial position by the return spring 212. At this time, the internal elastic body 216 urges the retainer in the right direction in the figure, so the locking mechanism 300a does not function, and the shaft 10 and the movable core 210 can move relative to each other. On the other hand, in the second electromagnetic portion 108b, the rolling elements 302 are urged against the forward inclined surface 312, so the locking mechanism 300b functions to prevent the shaft 10 from returning to the right in the figure. Therefore, by repeating energization and de-energization of the coil 200 of the first electromagnetic section 108a, it is possible to gradually feed the shaft 10 in the left direction in the figure, in a stepwise manner. Similarly, the second electromagnetic section 108b can step-feed the shaft 10 in the right direction in the figure.

That is, whether the two electromagnetic parts are arranged facing inward as shown in FIG. 1 or facing outward as shown in FIG. It is possible to move the

The configuration shown in FIG. 7 also has a magnetic path switching function. When the coil 200 is de-energized and the movable core 210 and stopper 214 are in close contact, a first magnetic path R1 is formed from the permanent magnet 220 through the stopper 214, the movable core 210, the fixed core 320, and the yoke 332.

On the other hand, when the coil 200 is excited and a second magnetic path R2 is formed from the coil 200 through the cover 230, the movable iron core 210, and the fixed iron core 320, the path of the second magnetic path R2 becomes magnetically saturated. Therefore, the path of the magnetic flux emitted from the permanent magnet 220 is switched to the third magnetic path R3 passing from the permanent magnet 220 to the stopper 214, the magnetic gap G, and the fixed iron core 320. Since the third magnetic path R3 does not pass through the movable core 210, it does not affect the attraction force of the movable core 210 by the coil 200.

Since the first magnetic path R1 passes through the movable core 210, the permanent magnet 220 attracts the movable core 210 at the initial position. Therefore, when an external force F is applied to the shaft 10 when the coil 200 is de-energized, the attraction force of the permanent magnet 220 is obtained in addition to the urging force of the return spring 212, so that the movement of the movable core 210 due to the external force F is prevented. This can increase the holding force of the shaft 10 when the shaft 10 is stopped.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is clear that those skilled in the art can come up with various changes and modifications within the scope of the claims, and these naturally fall within the technical scope of the present invention. Understood.

INDUSTRIAL APPLICABILITY The present invention can be used as an actuator that can actively move a shaft in both directions.

R1...first magnetic path, R2...second magnetic path, R3...third magnetic path, 10...shaft, 12...recess, 100...actuator, 102...housing, 104...yoke, 106a...first electromagnetic section , 106b...Second electromagnetic part, 200...Coil, 204...Fixed core, 210...Movable core, 212...Return spring, 214...Stopper, 216...Internal elastic body, 218...External elastic body, 220...Permanent magnet, 230... Cover, 300a, 300b...lock mechanism, 302...rolling element, 304...retainer, 310...engaging member, 312...tip side inclined surface, 314...base side inclined surface, 320...fixed core, 332...yoke, F... External force, G...magnetic gap

Claims (2)

Equipped with two electromagnetic parts arranged opposite to the shaft,
Each electromagnetic part includes a coil, a movable core, and a locking mechanism incorporated between the movable core and the shaft,
The locking mechanism is
a rolling element that rolls on the shaft to form a wedge;
an engaging member that is fixed to the movable core and includes two inwardly inclined surfaces that the rolling element abuts;
Of the two inwardly facing inclined surfaces, when the side on the initial position side of the movable iron core is called the original side inclined surface, and the side on which the movable iron core is excited and moves is called the forward side inclined surface,
The actuator further includes:
an internal elastic body disposed within the movable core and urging the rolling element toward the original inclined surface;
an external elastic body that is disposed outside the movable core and urges the rolling element toward the front inclined surface when the coil is de-energized;
The biasing force of the external elastic body is set to be larger than the biasing force of the internal elastic body,
engaging with the shaft in a direction in which the movable iron core moves when the coil is excited;
the coil is de-energized and does not engage the shaft in the direction in which the movable iron core returns;
An actuator characterized in that when the coil is de-energized and the movable core is at an initial position, the movable core of the other electromagnetic section engages with the shaft in a returning direction. a fixed core disposed between the coil and the movable core;
a stopper that the movable iron core abuts when the coil is de-energized;
a permanent magnet disposed on the opposite side of the stopper from the movable iron core,
The stopper has a magnetic gap between the permanent magnet and a member other than the movable iron core,
When the coil is de-energized and the movable core and the stopper are in close contact, a first magnetic path is formed from the permanent magnet to the movable core;
When the coil is excited and a second magnetic path is formed from the coil to the movable core, the first magnetic path passes from the permanent magnet to a third magnetic path that does not pass through the magnetic gap and does not pass through the movable core. The actuator according to claim 1, wherein the actuator switches to a magnetic path of.

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