JP2574367Y2 - Linear actuator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention is used for a hydraulic or pneumatic direct acting valve (hydraulic pneumatic direct acting valve), etc., and controls the hydraulic / pneumatic direct acting valve at a high speed, a high response and a high performance. A linear actuator that can be used.

[0002]

2. Description of the Related Art Conventionally, a linear actuator has been used as an actuator for a hydraulic / pneumatic direct-acting valve. A center yoke is provided in a yoke so as to face the coil. A central magnetic pole is provided facing the inside of the yoke, and a mover interposed between the central magnetic poles and movable between the central yoke and the center yoke is provided.

[0003] Permanent magnets are respectively mounted on both sides of the movable element facing the center yoke, and an output shaft having one end penetrating through the center yoke and connected to a hydraulic / pneumatic direct-acting valve or the like is attached to the movable element. And controlling the current flowing through the coil to control the thrust to the hydraulic / pneumatic direct acting valve or the like.

[0004] Conventionally, the movable section of the linear actuator has a circular cross section including a permanent magnet, whereas the center yoke has a square cross section.

[0005]

However, since the shape of the mover and the shape of the center yoke are different, the thrust characteristic is such that the inclination of the thrust (referred to as detent force) when the exciting current is zero amperes with respect to the displacement. The system was large and unstable.

For this reason, when the positioning control is performed by the linear actuator, the oscillation and the positioning accuracy are reduced, so that there is a problem in that it is difficult to use.

[0007]

As described above, in order to solve the conventional problems, in the present invention, a pair of center yokes provided to face each other in a yoke, and wound around each center yoke. And a pair of central magnetic poles provided in the yoke so as to face each other and orthogonal to the center yoke, and provided between the pair of central magnetic poles and movable between the pair of center yokes. Armature, permanent magnets respectively provided on both sides of the mover facing the center yoke, and an output shaft connected to the mover and movably penetrating through the pair of center yokes,
A differential transformer that is provided outside the yoke and detects displacement of the output shaft, wherein the current flowing through the coil is feedback-controlled based on the displacement of the output shaft detected by the differential transformer. The cross-sectional shape of the center yoke and the cross-sectional shape of the mover are configured to be the same.

[0008]

With the above arrangement, when an electric current is applied to the coil, the output shaft is displaced by the attraction force and the repulsive force generated between the permanent magnet and the pair of center yokes. At this time, the displacement of the output shaft is detected by the differential transformer, and the current flowing through the coil is feedback-controlled based on the displacement of the output shaft.

Further, the detent force is reduced by forming the cross-sectional shape of the center yoke and the cross-sectional shape of the mover in the same shape.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 3 is a schematic structural view of a linear actuator according to the present invention, and FIG. 4 is an enlarged view of a portion B in FIG.
3 and 4, the linear actuator 1 includes:
It is mainly composed of a yoke 3 and a mover 5.

The yoke 3 is formed by laminating a large number of cores, and is provided with a center yoke 7
A, 7B, center electrodes 8A, 8B orthogonal to the center yokes 7A, 7B and opposed to each other, and coils 9A, 9B wound around the center yokes 7A, 7B, respectively.

The mover 5 is interposed between the center electrodes 8A and 8B and is provided so as to be displaceable between the center yokes 7A and 7B. The center yokes 7A and 7B are provided on both sides of the mover 5. Permanent magnets 11 fixed to each other
A and 11B, and an output shaft 13 movably penetrating through the center yokes 7A and 7B directly connected to the mover 5. One end of the output shaft 13 is connected to a spool of a hydraulic / pneumatic valve (not shown), and the other end is in a differential transformer 15 provided outside the yoke 3.

With such a configuration, the linear actuator 1 controls the current to the coils 9A and 9B, thereby controlling the thrust generating surfaces of the permanent magnets 11A and 11A.
It is possible to control a displacement x as a thrust F which is a suction force and a repulsive force generated between the center yoke 7B and the center yokes 7A and 7B.

At this time, it is assumed that the displacement x of the output shaft 13 is detected by the differential transformer 15 and fed back to the control device (not shown) of the hydraulic / pneumatic valve. The output shaft linear bearing 17 is provided in the yoke 3 to make the displacement of the output shaft 13 smooth.

FIG. 1 shows an embodiment of the present invention.
FIG. In the figure, the center yoke 7A,
7B is formed in a circular shape having the same cross section as the mover 5. By forming the center yokes 7A and 7B in this manner, as shown in FIG. 2, the inclination of the thrust (detent force) with respect to the displacement of the thrust (detent force) at zero exciting current is smaller than the thrust characteristic line b according to the prior art. This shows that the thrust characteristic line a according to the present invention decreases.

Therefore, when such a linear actuator 1 according to the present invention is applied to the hydraulic / pneumatic valve, a stable system having good oscillation and positioning accuracy is formed, and high speed, high speed
High response and high performance valve control is possible.

The present invention is not limited to the above embodiment, but can be used in other modes by making appropriate design changes.
And the shape of the permanent magnets 11A and 11B
The same effect can be achieved even if the squares have the same shape as A and 7B.

The configuration of the present invention is summarized as follows.

That is, a pair of center yokes 7A and 7B provided in the yoke 3 so as to face each other and the center yokes 7A and 7B
B and coils 9A and 9B respectively wound around the center yoke and center yokes 7A and 7B
A pair of central electrodes 8A and 8B orthogonal to the movable member 5; a movable element 5 provided between the pair of central electrodes 8A and 8B and displaceable between the pair of center yokes 7A and 7B; Permanent magnets 11A and 11B provided on both side surfaces facing the center yokes 7A and 7B, respectively;
A pair of center yokes 7A directly connected to the mover 5 and
An output shaft 13 movably penetrating through the inside of the yoke 3; and a center yoke 7A provided outside the yoke 3 to feedback control the current flowing through the coils 9A and 9B based on the displacement of the output shaft 13. , 7B and the mover 5 are formed in the same shape.

The operation of this embodiment is summarized as follows.

That is, by passing a current through the coils 9A and 9B, the permanent magnets 11A and 11B and the center yoke 7
The output shaft 13 is displaced by the thrust F, which is a suction force and a repulsion force generated between the output shaft 13 and A and 7B. At this time, the displacement x of the output shaft 13 is detected by the differential transformer 15,
The current flowing through the coils 9A and 9B is feedback-controlled based on the displacement of the output shaft.

Further, since the cross-sectional shapes of the center yokes 7A and 7B and the cross-sectional shape of the mover 5 are the same, the detent force is reduced.

As described above, according to the present invention,
Since the differential transformer 15 for detecting the displacement of the output shaft 13 is provided and the current flowing through the coils 9A and 9B is feedback-controlled based on the displacement of the output shaft 13 detected by the differential transformer 15, The positioning accuracy is improved.

Further, the cross-sectional shape of the center yokes 7A and 7B and the cross-sectional shape of the mover 5 are configured to be the same to reduce the detent force, so that the positioning accuracy of the output shaft 13 is further improved, and the output shaft is improved. 13 is high speed and high response.

[0026]

According to the first aspect of the present invention, there is provided a differential transformer for detecting a displacement of an output shaft,
Since the current flowing through the coil is feedback-controlled based on the displacement of the output shaft detected by the differential transformer, the positioning accuracy of the output shaft is improved.

Further, since the cross-sectional shape of the center yoke and the cross-sectional shape of the mover are configured to be the same and the detent force is reduced, the positioning accuracy of the output shaft is further improved, and
High-speed, high-response positioning of the output shaft.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line AA of FIG. 3, which is an embodiment of the present invention.

FIG. 2 is a thrust characteristic diagram of a linear actuator.

FIG. 3 is a schematic configuration diagram of a linear actuator in which the present invention is implemented. l

FIG. 4 is an enlarged view of a portion B in FIG. 3;

[Explanation of symbols]

 Reference Signs List 1 linear actuator 3 yoke 5 mover 7A, 7B center yoke 9A, 9B coil 11A, 11B permanent magnet 13 output shaft 15 differential transformer

────────────────────────────────────────────────── (5) References JP-A-49-68922 (JP, A) JP-A-49-4154 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16K 31/06 H02K 7/14

Claims (1)

(57) [Scope of request for utility model registration] 1. A pair of center yokes provided to face each other in a yoke, a coil wound around each center yoke, and a coil provided to face the yoke and orthogonal to the center yoke. A pair of central magnetic poles, a mover provided between the pair of central magnetic poles and displaceable between the pair of center yokes, and permanent magnets respectively provided on both side surfaces of the mover facing the center yoke. ,
An output shaft connected to the mover and movably penetrating through a pair of center yokes; and a differential transformer provided outside the yoke and detecting displacement of the output shaft. The current flowing through the coil is feedback-controlled based on the displacement of the output shaft, and the cross-sectional shape of the center yoke and the cross-sectional shape of the mover are configured to be the same. Linear actuator.