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

Abstract

A linear actuator may include a fixed body having a coil wound around in a ring-shaped manner and a movable body. The movable body may include a first movable body side yoke which is disposed on the inner side of the coil and a pair of magnets which is laminated on both sides in an axial direction of the first movable body side yoke such that the same polarities of the magnets face the first movable body side yoke. The movable body may be driven in the axial direction. The linear actuator may be applied to a valve device and a pump device.

1 . A linear actuator comprising:
 a fixed body which includes a coil that is wound around in a ring-shaped manner; and   a movable body comprising:
 a first movable body side yoke which is disposed on an inner side or an outer side of the coil such that a peripheral face of the first movable body side yoke faces a peripheral face of the coil; and 
 a pair of magnets which is laminated on both sides in an axial direction of the first movable body side yoke such that the same polarities of the magnets face the first movable body side yoke; 
   wherein the movable body is driven in the axial direction by energization to the coil.   
     
     
         2 . The linear actuator according to  claim 1 , wherein the fixed body is disposed in the inner side of the coil, and an outer peripheral face of the first movable body side yoke and an inner peripheral face of the coil are facing each other. 
     
     
         3 . The linear actuator according to  claim 2 , wherein
 the fixed body includes a fixed body side yoke, one tip end part and another tip end part of the fixed body side yoke, which are extended from an outer peripheral side of the coil to an inner peripheral side of the coil through both sides in the axial direction of the coil, being disposed in a clearance between an outer peripheral face of the first movable body side yoke and an inner peripheral face of the coil,   the tip end parts of the fixed body side yoke face each other in the axial direction through a slit, and   a gap space is formed between the fixed body side yoke and the movable body.   
     
     
         4 . The linear actuator according to  claim 3 , wherein the fixed body side yoke is provided with a coil wire lead-out part for drawing out a terminal of a coil wire of the coil. 
     
     
         5 . The linear actuator according to  claim 3 , wherein the tip end part of the fixed side yoke is formed such that a width of the slit on the movable body side is substantially the same or narrower than a width of the slit on the coil side. 
     
     
         6 . The linear actuator according to  claim 3 , further comprising a spacer made of non-magnetic material which is disposed between the tip end parts of the fixed side yoke to connect the tip end parts of the fixed side yoke to each other. 
     
     
         7 . The linear actuator according to  claim 3 , wherein the outer peripheral face of the first movable body side yoke is protruded on an outer side from outer peripheral faces of a pair of the magnets. 
     
     
         8 . The linear actuator according to  claim 3 , further comprising a second movable body side yoke which is laminated on each of a pair of the magnets on an opposite side to the first movable body side yoke. 
     
     
         9 . The linear actuator according to  claim 8 , wherein an outer peripheral face of the second movable body side yoke is protruded on an outer side from an outer peripheral face of a pair of the magnets. 
     
     
         10 . The linear actuator according to  claim 1 , further comprising:
 a support shaft which is provided in the movable body and extended at least in one direction in the axial direction; and   a bearing member which is held in an opening part which opens in the axial direction in the fixed body for supporting the support shaft in a movable manner in the axial direction.   
     
     
         11 . The linear actuator according to  claim 1 , further comprising:
 a support shaft which is provided in the movable body and extended at least in one direction in the axial direction; and   a non-through hole or a through hole which is formed in at least the first movable body side yoke and the magnet into which the support shaft is inserted.   
     
     
         12 . The linear actuator according to  claim 1 , further comprising an urging member for urging the movable body at least in one axial direction. 
     
     
         13 . A valve device comprising the linear actuator as recited in  claim 1 , wherein a flow passage is opened and closed or a cross sectional area of the flow passage is increased and decreased by an operation in the axial direction of the movable body to control flow of fluid. 
     
     
         14 . The valve device according to  claim 13 , further comprising a valve element which is connected to the movable body for opening and closing the flow passage or increasing and decreasing the cross sectional area of the flow passage to control flow of fluid. 
     
     
         15 . The valve device according to  claim 14 , wherein the valve element is disposed on both sides in the axial direction of the movable body. 
     
     
         16 - 28 . (canceled)