Linear actuator, and pump device and compressor device using the same

Abstract

A linear actuator includes a driving part provided with an inner yoke and an outer yoke, a magnet disposed between the inner yoke and the outer yoke, and a movable body which is to be driven to reciprocate in the axial direction. The driving part includes a coil for generating an alternating magnetic field in a first gap space and a second gap space which are formed between the inner yoke and the outer yoke. The movable body is interlocked and driven with the alternating magnetic field. The driving part further includes a coupling means disposed along the axial direction in a gap space which is formed by the outer yokes adjacent to each other in a circumferential direction or by the inner yokes adjacent to each other in the circumferential direction. The coupling means connects the driving part to a main body part side which is provided with a moved body that is driven by the movable body.

1 . A linear actuator comprising: 
 a driving part including: 
 a plurality of inner yokes which are disposed in a circumferential direction and, each of which has a planar opposing face;  
 a plurality of outer yokes which are disposed in a circumferential direction around the inner yokes such that a first gap space and a second gap space separated from each other in an axial direction are formed between an outer peripheral face of the inner yoke and the outer yoke, and each of the plurality of outer yokes has a planar opposing face to the inner yoke;  
 a coil for generating an alternating magnetic field in the first gap space and the second gap space, whose magnetic path is formed by the outer yoke, the first gap space, the inner yoke, the second gap space and the outer yoke; and  
 a coupling means which is disposed along the axial direction in a gap space which is formed by the outer yokes adjacent to each other in a circumferential direction or by the inner yokes adjacent to each other in the circumferential direction;  
   a magnet which is disposed between the inner yoke and the outer yoke; and    a movable body which is interlocked with the alternating magnetic field to be driven to reciprocate in the axial direction;    wherein the coupling means connects the driving part to a main body part side which is provided with a moved body that is driven by the movable body.    
   
   
       2 . The linear actuator according to  claim 1 , further comprising a drop-out preventing part which is provided in the driving part for being capable of abutting with the coupling means to prevent the coupling means from dropping out in a direction which is opposite to a direction that the driving part is coupled to the main body part by the coupling means.  
   
   
       3 . The linear actuator according to  claim 2 , wherein the coupling means is disposed along the axial direction in the gap space which is formed by the outer yokes adjacent to each other in the circumferential direction, and the drop-out preventing part is constructed by being integrally molded to an electrically insulative coil bobbin on which the coil is wound around and by which isolation from the outer yoke is ensured.  
   
   
       4 . The linear actuator according to  claim 3 , wherein the outer yoke is formed to extend from a portion located on an outer circumferential side of the coil to an inner circumferential side over end faces of the coil in the axial direction to form a first facing portion for constructing the first gap space and a second facing portion for constructing the second gap space such that the respective first facing portion and the second facing portion are opposed to the inner yoke, and the drop-out preventing part is formed to protrude to a position which is nearer on the main body part side than the outer yoke.  
   
   
       5 . The linear actuator according to  claim 2 , wherein the coupling means is disposed along the axial direction in the gap space which is formed by the outer yokes adjacent to each other in the circumferential direction and is disposed at a position which is nearer on the main body part side than the outer yoke, and a part of the coupling means overlaps with the outer yoke in the axial direction.  
   
   
       6 . The linear actuator according to  claim 2 , wherein the coupling means includes a male screw, which is capable of retreating within the driving part to a position where the male screw abuts with the drop-out preventing part.  
   
   
       7 . The linear actuator according to  claim 2 , wherein the coupling means includes a male screw which is disposed along the axial direction in the gap space that is formed by the outer yokes adjacent to each other in the circumferential direction, the male screw is formed with an engaging recessed part with which the male screw is rotated, and the male screw and the drop-out preventing part disposed in the gap space between the outer yokes, which are adjacent to each other in the circumferential direction, overlap with each other in the axial direction excluding the engaging recessed part of the male screw.  
   
   
       8 . A pump device comprising: 
 a linear actuator recited in one of claims  1  through  7 .    
   
   
       9 . A compressor device comprising: 
 a linear actuator recited in one of claims  1  through  7 .    
   
   
       10 . A linear actuator comprising: 
 a driving part including: 
 a plurality of inner yokes which are disposed in a circumferential direction and, each of the plurality of inner yokes has a planar opposing face to a corresponding outer yoke;  
 the plurality of outer yokes which are disposed in a circumferential direction around the inner yokes and each of the plurality of outer yokes has a planar opposing face to the corresponding inner yoke, wherein the plurality of outer yokes are disposed such that a first gap space and a second gap space separated from each other in an axial direction are formed between the planar opposing face of the inner yoke and the planar opposing face of the outer yoke;  
 a coil for generating an alternating magnetic field in the first gap space and the second gap space, whose magnetic path is formed by the outer yoke, the first gap space, the inner yoke, the second gap space and the outer yoke; and  
 a coupling means which is disposed along the axial direction in a gap space;  
   a magnet that is disposed between the inner yoke and the outer yoke; and    a movable body that is driven by the driving part so as to reciprocate in the axial direction;    wherein the coupling means connects the driving part to a main body part side which is provided with a moved body that is driven by the movable body.    
   
   
       11 . The linear actuator according to  claim 10 , wherein the coupling means is formed by the outer yokes adjacent to each other in a circumferential direction.  
   
   
       12 . The linear actuator according to  claim 10 , wherein the coupling means is formed by the inner yokes adjacent to each other in the circumferential direction;  
   
   
       13 . The linear actuator according to  claim 10 , further comprising a drop-out preventing part which is provided in the driving part for being capable of abutting with the coupling means to prevent the coupling means from dropping out in a direction which is opposite to a direction that the driving part is coupled to the main body part by the coupling means.  
   
   
       14 . The linear actuator according to  claim 13 , wherein the coupling means is disposed along the axial direction in the gap space which is formed by the outer yokes adjacent to each other in the circumferential direction, and the drop-out preventing part is constructed by being integrally molded to an electrically insulative coil bobbin on which the coil is wound around and by which isolation from the outer yoke is ensured.  
   
   
       15 . The linear actuator according to  claim 14 , wherein the outer yoke is formed to extend from a portion located on an outer circumferential side of the coil to an inner circumferential side over end faces of the coil in the axial direction to form a first facing portion for constructing the first gap space and a second facing portion for constructing the second gap space such that the respective first facing portion and the second facing portion are opposed to the inner yoke, and the drop-out preventing part is formed to protrude to a position which is nearer on the main body part side than the outer yoke.  
   
   
       16 . The linear actuator according to  claim 11 , wherein the coupling means is disposed at a position which is nearer on the main body part side than the outer yoke, and a part of the coupling means overlaps with the outer yoke in the axial direction.  
   
   
       17 . The linear actuator according to  claim 13 , wherein the coupling means includes a male screw, which is capable of retreating within the driving part to a position where the male screw abuts with the drop-out preventing part.  
   
   
       18 . The linear actuator according to  claim 13 , wherein the coupling means includes a male screw which is disposed along the axial direction in the gap space that is formed by the outer yokes adjacent to each other in the circumferential direction, the male screw is formed with an engaging recessed part with which the male screw is rotated, and the male screw and the drop-out preventing part disposed in the gap space between the outer yokes, which are adjacent to each other in the circumferential direction, overlap with each other in the axial direction excluding the engaging recessed part of the male screw.  
   
   
       19 . A pump device comprising: 
 a linear actuator, the linear actuator comprising: 
 a driving part including: 
 a plurality of inner yokes which are disposed in a circumferential direction and, each of the plurality of inner yokes has a planar opposing face to a corresponding outer yoke;  
 the plurality of outer yokes which are disposed in a circumferential direction around the inner yokes and each of the plurality of outer yokes has a planar opposing face to the corresponding inner yoke, wherein the plurality of outer yokes are disposed such that a first gap space and a second gap space separated from each other in an axial direction are formed between the planar opposing face of the inner yoke and the planar opposing face of the outer yoke;  
 a coil for generating an alternating magnetic field in the first gap space and the second gap space, whose magnetic path is formed by the outer yoke, the first gap space, the inner yoke, the second gap space and the outer yoke; and  
 a coupling means which is disposed along the axial direction in a gap space;  
 
 a magnet that is disposed between the inner yoke and the outer yoke; and  
 a movable body that is driven by the driving part so as to reciprocate in the axial direction;  
 wherein the coupling means connects the driving part to a main body part side which is provided with a moved body that is driven by the movable body.  
   
   
   
       20 . The pump device of  claim 19 , wherein the coupling means of the linear actuator is formed by the outer yokes adjacent to each other in a circumferential direction.  
   
   
       21 . The pump device of  claim 19 , wherein the coupling means of the linear actuator is formed by the inner yokes adjacent to each other in the circumferential direction.  
   
   
       22 . The pump device of  claim 19 , wherein the linear actuator further comprises a drop-out preventing part which is provided in the driving part for being capable of abutting with the coupling means to prevent the coupling means from dropping out in a direction which is opposite to a direction that the driving part is coupled to the main body part by the coupling means.  
   
   
       23 . A compressor device comprising: 
 a linear actuator, the linear actuator comprising: 
 a driving part including: 
 a plurality of inner yokes which are disposed in a circumferential direction and, each of the plurality of inner yokes has a planar opposing face to a corresponding outer yoke;  
 the plurality of outer yokes which are disposed in a circumferential direction around the inner yokes and each of the plurality of outer yokes has a planar opposing face to the corresponding inner yoke, wherein the plurality of outer yokes are disposed such that a first gap space and a second gap space separated from each other in an axial direction are formed between the planar opposing face of the inner yoke and the planar opposing face of the outer yoke;  
 a coil for generating an alternating magnetic field in the first gap space and the second gap space, whose magnetic path is formed by the outer yoke, the first gap space, the inner yoke, the second gap space and the outer yoke; and  
 a coupling means which is disposed along the axial direction in a gap space;  
 
 a magnet that is disposed between the inner yoke and the outer yoke; and  
 a movable body that is driven by the driving part so as to reciprocate in the axial direction;  
 wherein the coupling means connects the driving part to a main body part side which is provided with a moved body that is driven by the movable body.  
   
   
   
       24 . The compressor device of  claim 23 , wherein the coupling means of the linear actuator is formed by the outer yokes adjacent to each other in a circumferential direction.  
   
   
       25 . The compressor device of  claim 23 , wherein the coupling means of the linear actuator is formed by the inner yokes adjacent to each other in the circumferential direction.  
   
   
       26 . The compressor device of  claim 23 , wherein the linear actuator further comprises a drop-out preventing part which is provided in the driving part for being capable of abutting with the coupling means to prevent the coupling means from dropping out in a direction which is opposite to a direction that the driving part is coupled to the main body part by the coupling means.