WO2018174039A1 - Linear actuator - Google Patents

Linear actuator Download PDF

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Publication number
WO2018174039A1
WO2018174039A1 PCT/JP2018/010929 JP2018010929W WO2018174039A1 WO 2018174039 A1 WO2018174039 A1 WO 2018174039A1 JP 2018010929 W JP2018010929 W JP 2018010929W WO 2018174039 A1 WO2018174039 A1 WO 2018174039A1
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WO
WIPO (PCT)
Prior art keywords
rotation
axial direction
output shaft
linear actuator
shaft
Prior art date
Application number
PCT/JP2018/010929
Other languages
French (fr)
Japanese (ja)
Inventor
稲垣　正明
Original Assignee
ミネベアミツミ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ミネベアミツミ株式会社 filed Critical ミネベアミツミ株式会社
Priority to DE112018001546.7T priority Critical patent/DE112018001546T5/en
Priority to CN201880018608.3A priority patent/CN110418910A/en
Priority to JP2019507679A priority patent/JP6768144B2/en
Publication of WO2018174039A1 publication Critical patent/WO2018174039A1/en

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/06—Means for converting reciprocating motion into rotary motion or vice versa
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
    • H02K1/278—Surface mounted magnets; Inset magnets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H2025/2031—Actuator casings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H2025/204—Axial sliding means, i.e. for rotary support and axial guiding of nut or screw shaft
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H2025/2062—Arrangements for driving the actuator
    • F16H2025/2075—Coaxial drive motors
    • F16H2025/2078—Coaxial drive motors the rotor being integrated with the nut or screw body
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
    • H02K5/173—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using bearings with rolling contact, e.g. ball bearings
    • H02K5/1732—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using bearings with rolling contact, e.g. ball bearings radially supporting the rotary shaft at both ends of the rotor

Definitions

  • the present invention relates to a linear actuator.
  • Patent Document 1 A linear actuator having a structure for converting the rotation of the rotor into a linear motion of the output shaft is known (for example, see Patent Document 1).
  • Patent Document 1 employs a structure in which a stop pin is attached to the output shaft and the stop pin slides in a groove on the housing side.
  • the output shaft cannot protrude any more because the stop pin contacts the inside of the flange portion of the housing. In this state, the stop pin makes line contact with the inner portion of the housing flange. For this reason, as the use is repeated, the stop pin bites into the inside of the flange, and deformation and wear of the inside of the flange occur. As a result, a shift occurs in the movable range of the output shaft, and the accuracy as a linear actuator decreases.
  • the present invention provides a linear actuator having a structure that converts the rotation of the rotor into a linear motion of the output shaft, and prevents the output shaft from rotating and is movable in the axial direction.
  • the purpose is to provide technology that can improve
  • the present invention is provided with a housing, a rotor held rotatably in the housing, an output shaft movable in an axial direction different from the rotation direction of the rotor as the rotor rotates, and the housing
  • a rotation-preventing member that is disposed in the axially extending space and has a first surface that intersects the axial direction, and is slidable in the axial direction inside the space;
  • a non-rotating member fixed to a shaft, and the housing is a linear actuator provided with a second surface that can contact the first surface of the non-rotating member.
  • the anti-rotation member has a cylindrical shape, and an outer peripheral surface of the cylindrical shape is slidable on an inner peripheral surface of the space, and the shape of the anti-rotation member viewed from the axial direction. Is a form having an asymmetric shape with respect to rotation other than 360 ° with the output shaft as the rotation center.
  • the outer peripheral surface of the rotation preventing member includes a first curved surface having a first curvature, a second curved surface having a second curvature, the first curved surface, and the second curved surface.
  • step difference is mentioned.
  • the anti-rotation member is made of resin
  • the output shaft is provided with a hole penetrating in a direction intersecting the axial direction, and the resin constituting the anti-rotation member is inside the hole.
  • the anti-rotation member is fixed to the output shaft in a state where the hole is filled, and there is a specific relationship between the direction of the hole and the asymmetric shape.
  • the rotor has a first screw structure
  • the output shaft has a second screw structure meshed with the first screw structure, the position of the detent member on the output shaft, and the first
  • the relationship between the screw structure of 1 and the tooth meshing position in the second screw structure is set to a specific relationship.
  • a linear actuator having a structure that converts rotation of a rotor into linear motion of an output shaft, it is possible to prevent rotation of the output shaft and increase the accuracy of movement of the output shaft in a structure that is movable in the axial direction.
  • FIG. 1 shows a linear actuator 100 according to an embodiment.
  • FIG. 2 shows an exploded perspective view of the linear actuator 100.
  • FIG. 3 shows a sectional view of the linear actuator 100 (a sectional view taken along the axis).
  • the linear actuator 100 is fixed to a stator yoke 115 having an end surface 115a in the axial direction, a bobbin 113 (see FIG. 4A) around which the coil 111 is wound, and an end surface 115a of the stator yoke 115.
  • the front plate 120 and the front housing 150 coupled to the front plate 120 are provided.
  • the bobbin 113 is provided with a boss portion 14 to be inserted into a hole 121 (see FIGS. 2 and 5A) provided in the front plate 120.
  • the front housing 150 is provided with a boss 152 (see FIGS.
  • the axial direction is the direction of the Z axis in the figure, and is defined as the extending direction of the shaft 140 described later.
  • the linear actuator 100 includes a stator structure 110, a front plate 120, a rotor 130, a shaft 140, a front housing 150, and a tip portion 142.
  • the stator structure 110 has a substantially cylindrical shape and a claw pole type stepping motor stator structure.
  • Stator structure 110 includes coils 111 and 112 (see FIG. 3), bobbins 113 and 114, stator yokes 115 and 117 made of a soft magnetic metal material such as an electromagnetic steel plate, and stator yokes 116 and 118, and an internal gap.
  • the resin 119 (see FIGS. 3 and 5A) is filled and integrated.
  • the stator yokes 115 and 117 constitute a pair and constitute a stator yoke of the first claw pole type motor
  • the stator yokes 116 and 118 constitute a pair and constitute a stator yoke of the second claw pole type motor.
  • the stator yokes 115 and 116 are called outer yokes
  • the stator yokes 117 and 118 are called inner yokes.
  • the coil 111 forms a field coil and is wound around a resin bobbin 113 (see FIG. 4A).
  • the bobbin 113 around which the coil 111 is wound is housed inside the stator structure 110 (stator yoke 115).
  • the bobbin 113 is manufactured by an injection molding method using a resin, and includes a cylindrical portion 11 (see FIG. 4A), and flange portions 12 and 13 extending radially outward from both ends of the cylindrical portion 11 in the axial direction. ing.
  • One flange portion 12 is provided with three boss portions 14 that are protruding portions protruding in the axial direction.
  • the boss portions 14 are provided at positions at equal angular intervals (every 120 °).
  • the boss portion 14 is formed as a part of the bobbin 113 simultaneously with the bobbin 113 by an injection molding method.
  • a hole 15 for fixing the terminal pin 125 is formed in the upper portion of the bobbin 113.
  • a lead wire drawn from the coil 111 is connected to a terminal pin 125 (see FIG. 3) fixed to the hole 15.
  • the stator yoke 115 has an outer cylindrical portion, an inner tooth portion, and a plate-shaped flat ring portion connecting the outer cylindrical portion and the inner tooth portion (the back surface of the flat ring portion is the end surface 115a of the stator yoke 115). .
  • a bobbin 113 around which a coil 111 is wound is accommodated between the outer cylindrical portion and the inner tooth portion.
  • the inner tooth portion of the stator yoke 115 has a plurality of first teeth 115b (see FIGS. 3 and 5A) extending in the axial direction (direction of the end housing 170).
  • the stator yoke 117 is a member paired with the stator yoke 115, and has a plate-shaped flat ring portion and a plurality of second teeth 117b extending in the axial direction from the inner edge of the flat plate ring portion (see FIG. 5A: FIG. 3). Is not visible).
  • the plurality of first teeth 115b and the plurality of second teeth 117b extend in directions opposite to each other and are in a positional relationship in which they are engaged with each other with a gap therebetween. . This is the same as in the case of a normal claw pole type motor.
  • a gap between the first teeth 115b and the second teeth 117b is filled with a resin 119 filled in the stator structure 110.
  • the bobbin 114 is also made of resin, and the coil 112 is wound around it.
  • the stator yokes 116 and 118 have a positional relationship structure in which a plurality of teeth are engaged with each other in a state of having gaps alternately.
  • a space between the teeth of the stator yoke 116 and the teeth of the stator yoke 118 is filled with a resin 119 filled in the stator structure 110.
  • the end face 115a of the stator yoke 115 is provided with three holes 115c (see FIG. 3) through which the boss part 14 of the bobbin 113 is inserted, and the boss part 14 is inserted into the three holes 115c.
  • the tip of the boss portion 14 inserted into the hole 115c protrudes from the hole 115c to the front housing 150 side.
  • FIGS. 5A and 5B show a state in which the front plate 120 is attached to the stator yoke 115 (stator structure 110).
  • the front plate 120 is made of metal and is fixed to the stator yoke 115 by welding.
  • the front plate 120 is provided with three holes 121 into which the three boss portions 14 protruding in the axial direction from the stator yoke 115 are fitted.
  • the front plate 120 is positioned with respect to the stator yoke 115 by fitting the three boss portions 14 into the three holes 121.
  • the front plate 120 is provided with three fixing arm portions 122 having openings 122a at the tips.
  • the fixing arm portion 122 is a member that couples the front plate 120 and the front housing 150, and functions as a support portion that supports the front housing 150 on the front plate 120. As shown in FIG. 1, the front plate 120 is coupled to the front housing 150 by deforming the fixing arm portion 122 and engaging the opening 122 a (see FIG. 2) with the protrusion 151 of the front housing 150.
  • FIG. 6A is a perspective view of the front housing 150
  • FIG. 6B is a front view thereof.
  • the front housing 150 is made of resin and is formed by an injection molding method.
  • the front housing 150 is provided with three boss portions 152 that are protruding portions protruding in the axial direction.
  • the boss portion 152 is manufactured by an injection molding method using a resin, and the boss portion 152 is simultaneously formed as a part of the front housing 150 at the time of manufacturing.
  • the boss portion 152 is inserted into the hole 123 provided in the front plate 120 and passes through the inside of the hole 123.
  • the bottom portion of the hole 123 exposes the axial end surface 115a of the stator yoke 115 (see FIG. 5A), and the tip of the boss 152 contacts the axial end surface 115a of the stator yoke 115.
  • the protruding length of the boss portion 14 provided on the bobbin 113 is set to a dimension such that the tip thereof does not contact the front housing 150.
  • the protruding length of the boss portion 14 from the end surface of the bobbin 113 is set to a dimension that does not protrude from the hole 121.
  • the rotor 130 is held inside the stator structure 110 in a rotatable state.
  • the rotor 130 includes an inner cylindrical member 131, a cylindrical rotor magnet 132 fixed to the outside of the inner cylindrical member 131, and a cylindrical female screw 133 having a female screw structure formed on the inner periphery fixed to the inner side of the inner cylindrical member 131. have.
  • the rotor magnet 132 is a permanent magnet that is alternately magnetized with NSNS... Along the circumferential direction.
  • the internal thread 133 meshes with an external thread structure 141 formed on the outer periphery of an elongated cylindrical shaft 140.
  • the inner cylindrical member 131 constituting the rotor 130 is held in a freely rotatable state by ball bearings 134 and 135. More specifically, the outer ring of the ball bearing 134 is fixed to an end housing 170 fixed to the stator yoke 116, and the inner ring of the ball bearing 134 is fixed to an inner cylindrical member 131 constituting the rotor 130 ( The outer ring of the ball bearing 134 is in contact with the end housing 170 but not the rotor 130). The outer ring of the ball bearing 135 is fixed to the front housing 150, and the inner ring of the ball bearing 135 is fixed to the inner cylindrical member 131 constituting the rotor 130 (the outer ring of the ball bearing 135 is in contact with the front housing 150. But not in contact with the rotor 130). That is, the rotor 130 is held in a freely rotatable state by the ball bearings 134 and 135 with respect to the end housing 170 and the front housing 150.
  • a distal end portion 142 is fixed to the distal end of the shaft 140 by a pin 144.
  • 7A and 7B show a shaft 140 serving as an output shaft.
  • a rotation preventing member 143 is fixed to the shaft 140.
  • the anti-rotation member 143 has a substantially cylindrical shape, and is made of resin and assembled to the shaft 140 by integral molding by injection molding.
  • the shaft 140 is provided with a hole 140a penetrating in a direction perpendicular to the axial direction, and the anti-rotation member 143 is formed so that the resin 143d constituting the anti-rotation member 143 enters the hole 140a.
  • the material which comprises the rotation prevention member 143 is not restricted to resin, For example, the sintered member mentioned later in FIG. 10 may be sufficient.
  • One end in the axial direction of the anti-rotation member 143 is a planar end surface 143b (first surface), and the other end is an end surface 143c.
  • the end faces 143b and 143c are planes perpendicular to the axial direction.
  • the end surface 143b contacts the contact surface 154a (second surface) of the inner flange portion 154, so that the shaft 140 does not protrude from the front housing 150 any more.
  • the contact surface 154a of the inner flange portion 154 facing the end surface 143b in the axial direction is also a plane perpendicular to the axial direction, and the contact between the end surface 143b and the contact surface 154a of the inner flange portion 154 is a surface contact.
  • FIG. 7B shows a cross-sectional shape perpendicular to the axial direction of the detent member 143 attached to the shaft 140.
  • FIG. 8 shows an example of the shape of the anti-rotation member 143 as viewed from the axial direction that is asymmetric with respect to rotation other than 360 ° with the shaft 140 as the rotation center.
  • the outer peripheral surface of the rotation preventing member 143 in this example includes an upper curved surface 161, a lower curved surface 162, and two side surfaces 163 and 164 that connect the upper curved surface 161 and the lower curved surface 162.
  • the upper curved surface 161 and the lower curved surface 162 are part of cylindrical curved surfaces having different curvatures, and the side surfaces 163 and 164 are flat surfaces.
  • the side surfaces 163 and 164 and the lower curved surface 162 are directly connected to each other through a step between the side surfaces 163 and 164 and the upper curved surface 161.
  • both the lower curved surface 162 and the upper curved surface 161 may be directly connected to the side surfaces 163 and 164, and the side surface 163 and the side surface 164 may not be parallel to each other.
  • the cross-sectional shape of the inner surface of the columnar space 153 described later may be a shape corresponding to the cross-sectional shape of the rotation preventing member 143.
  • the front housing 150 has a cylindrical portion 156 extending in the axial direction, and a columnar space 153 that is a columnar space in which the shaft 140 and the rotation preventing member 143 are accommodated is provided inside the cylindrical portion 156.
  • the cross section perpendicular to the axial direction is set to a shape corresponding to the cross sectional shape of the rotation preventing member 143.
  • FIG. 9 shows a cross-sectional shape of the columnar space 153 viewed from the axial direction. As shown in FIG.
  • the inner surface of the columnar space 153 viewed from the axial direction is composed of an upper curved surface 171, a lower curved surface 172, and two side surfaces 173 and 174 that are planes connecting the upper curved surface 171 and the lower curved surface 172. ing.
  • the upper curved surface 171 contacts the upper curved surface 161 of the rotation preventing member 143 in a slidable state, or the upper curved surface 171 and the upper curved surface 161 are separated from each other by a predetermined interval.
  • the lower curved surface 172 contacts the lower curved surface 162 of the rotation preventing member 143 in a slidable state, or the upper curved surface 172 and the upper curved surface 162 are separated by a predetermined distance.
  • the side surface 173 contacts the side surface 163 of the detent member 143 in a slidable state.
  • the side surface 174 contacts the side surface 164 of the detent member 143 in a slidable state. That is, the dimension of the rotation preventing member 143 and the dimension of the columnar space 153 are set so that the rotation preventing member 143 cannot rotate in the columnar space 153 and can move in the axial direction while sliding.
  • the contact state between the side surface 173 and the side surface 163 and the contact state between the side surface 174 and the side surface 164 include a first case where surface contact is made and a second case where contact is not made.
  • the first case the side surface 173 and the side surface 163 are in surface contact with each other and are in a slidable state.
  • the side surface 174 and the side surface 164 are in surface contact with each other and are in a slidable state. In this case, high dimensional accuracy is required.
  • a slight gap having a width of several ⁇ m to several tens of ⁇ m is provided between the side surface 173 and the side surface 163 and between the side surface 174 and the side surface 164, and the rotation preventing member is provided with respect to the columnar space 153.
  • a state in which 143 is movable is realized.
  • the outer peripheral surface of the rotation preventing member 143 to be rotated and the inner peripheral surface of the columnar space 153 are in contact with each other at the edge portion of the surface, and thus are basically in line contact.
  • the curvature of the upper curved surface 161 and the curvature of the lower curved surface 162 are set to different values.
  • the curvature of the upper curved surface 171 and the curvature of the lower curved surface 172 are also different.
  • the anti-rotation member 143 cannot be accommodated in the columnar space 153 unless the upper curved surfaces 161 and 171 face each other and the lower curved surfaces 162 and 172 face each other.
  • a cylindrical portion 156 that constitutes a part of the columnar space 153 extends from the front housing 150, and an inner flange portion 154 is formed at the tip of the cylindrical portion 156.
  • a hole is provided at the center of the inner flange portion 154, and a shaft 140 that is an output shaft protrudes outside from the hole.
  • One end side (left side in FIG. 3) of the columnar space 153 is defined by an inner flange portion 154, and the other end side (right side in FIG. 3) is defined by a bearing housing space 135a in which the ball bearing 135 is housed.
  • a groove 155 formed in the front housing 150 is formed in the bearing housing space 135a. The groove 155 is formed in the front housing 150 so that the end surface (the left side in FIG.
  • the operating range of the distal end portion 142 in the outer direction is determined by the rotation preventing member 143 coming into contact with the inner flange portion 154 of the columnar space 153, and the movable range in the inner direction (right direction in FIG. 3). Is determined by the front end portion 142 hitting the inner flange portion 154 of the columnar space 153.
  • the rotor 130 and the internal thread 133 are rotated together by the above driving force.
  • the shaft 140 cannot be rotated by the anti-rotation member 143 and is movable in the axial direction, the shaft 140 having the male screw structure 141 meshed with the female screw 133 is rotated by the rotation of the female screw 133. Advance and retreat in the direction.
  • the moving direction of the shaft 140 is determined by the rotating direction of the rotor 130. As the shaft 140 moves in the axial direction, the distal end portion 142 moves in the axial direction.
  • the linear actuator 100 is rotatably supported by the front housing 150, the front housing 150, the shaft-shaped rotor 130 having an internal thread 133 inside, and a shaft 140 provided on the outer periphery with an external thread structure meshed with the internal thread 133.
  • the front housing 150 is provided with a contact surface 154a that can contact the end surface 143b in the axial direction of the anti-rotation member 143 so that the shaft 140 protrudes. In the maximum state, the end face 143 in the axial direction of the anti-rotation member 143 There is in surface contact with the contact surface 154a of the front housing 150.
  • the anti-rotation member 143 has a cylindrical shape as a whole, and the cylindrical outer peripheral surface is slidable relative to the inner peripheral surface of the columnar space 153, and the anti-rotation member viewed from the axial direction.
  • the shape of 143 is symmetric with respect to 360 ° rotation about the shaft 140 as the rotation center, and is asymmetric with respect to rotation other than 360 °.
  • the outer peripheral surface of the anti-rotation member 143 includes an upper curved surface 161 having a first curvature, a lower curved surface 162 having a second curvature different from the upper curved surface 161, and an upper curved surface 161 and a lower curved surface 162.
  • the contact area is large, and thus the inner peripheral surface of the cylindrical portion 156 and the rotation preventing member 143 described above. One or both of them are less likely to wear.
  • the side surface 173 and the side surface 163 and the side surface 174 and the side surface 164 are basically in line contact. Compared with the contact by the point inside the housing by the stop pin, the contact area is large, and wear on one or both of the inner peripheral surface of the cylindrical portion 156 and the anti-rotation member 143 is suppressed.
  • the anti-rotation member 143 is made of resin, the shaft 140 is provided with a hole 140a penetrating in a direction perpendicular to the axis, and the resin constituting the anti-rotation member 143 is filled in the hole 140a, The anti-rotation member 143 is fixed to the shaft 140, and there is a specific relationship between the direction of the hole 140a and the asymmetric shape of the anti-rotation member 143.
  • the direction of the anti-rotation member 143 in the vertical (Y-axis) direction during insertion into the columnar space 153 is uniquely determined. That is, the anti-rotation member 143 cannot be inserted into the columnar space 153 by turning it upside down (rotating 180 degrees around the axis). That is, when the shaft 140 is inserted into the columnar space 153, there is no concern that the shaft 140 is inserted into the columnar space 153 in a direction different from a predetermined direction.
  • the detent member 143 can be turned upside down and inserted into the columnar space 153 while attached to the shaft 140, the male thread structure 141 is displaced by a half pitch of the thread. That is, depending on the assembly method, a setting error corresponding to the half pitch of the thread occurs. When precise control such as 0.1 mm unit is required, the above setting error cannot be ignored.
  • the direction in the vertical direction when inserted into the columnar space 153 is uniquely determined, the above-described problem of setting errors corresponding to the half thread pitch does not occur. Further, since the asymmetric shape is determined by the direction of the hole, the rotational position of the shaft is determined by the direction of the hole, and the occurrence of errors during assembly can be suppressed.
  • the rotational position around the axis of the shaft 140 to which the anti-rotation member 143 is attached is unambiguous. Therefore, in the state where the anti-rotation member 143 contacts the contact surface 154a of the front housing 150, the male screw structure 141 and the female screw The relationship between the tooth meshing position at 133 and the position of the anti-rotation member 143 in the axial direction can be determined precisely.
  • the anti-rotation member 143 is turned upside down, that is, rotated 180 °, it can be inserted into the columnar space 153, a setting error corresponding to a half pitch of the thread of the male screw structure 141 occurs in the above setting.
  • the positioning accuracy includes a difference corresponding to a half pitch of the thread of the male screw structure 141.
  • FIG. 10 shows an example of a structure in which a rotation preventing member 160 is fixed to the shaft 140 with a pin 161.
  • the outer shape of the anti-rotation member 160 is the same as that of the anti-rotation member 143.
  • the material constituting the rotation preventing member 160 is a sintered member.
  • Examples of asymmetric shapes with respect to rotations other than 360 ° with the shaft 140 as the rotation center include trapezoids, odd-numbered squares such as triangles, pentagons, and heptagons (excluding regular polygons). Even if the figure itself has rotational symmetry such as a circle, ellipse, regular polygon, etc., as long as the shaft 140 passes through a position deviated from the center, it is asymmetric with respect to rotations other than 360 °. It corresponds to a simple shape.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
  • Transmission Devices (AREA)

Abstract

In order to prevent the rotation of an output shaft and increase the precision with which the output shaft can move, this linear actuator (100), which has a structure for converting the rotation of a rotor to linear motion of an output shaft, is equipped with: a front housing (150); a tubular rotor (130) held thereon in a rotatable manner, and having on the inside an internal thread (133); a shaft (140) the outer circumference of which is provided with an external thread structure for meshing with the internal thread (133); and a rotation prevention member (143) that is housed in a columnar space (153) provided on the front housing (150) and extending in the axial direction, and that does not rotate with respect to the front housing (150), is able to slide in the axial direction inside the columnar space (153), and is secured to the shaft (140). A contact surface (154a) with which an axial end surface (143b) of the rotation prevention member (143) can make contact is provided in the front housing (150), and when the shaft (140) protrudes as far as possible the end surface (143b) makes surface contact with the contact surface (154a).

Description

リニアアクチュエータLinear actuator
　本発明は、リニアアクチュエータに関する。 The present invention relates to a linear actuator.
　ロータの回転を出力軸の直線運動に変換する構造のリニアアクチュエータが知られている（例えば、特許文献１参照）。上記のリニアアクチュエータでは、出力軸が軸方向に移動可能で、且つ、回転できない構造とする必要がある。この構造に関して、特許文献１では、出力軸にストップピンを装着し、ストップピンが筐体側の溝の中を摺動する構造が採用されている。 A linear actuator having a structure for converting the rotation of the rotor into a linear motion of the output shaft is known (for example, see Patent Document 1). In the above linear actuator, it is necessary to have a structure in which the output shaft can move in the axial direction and cannot rotate. With regard to this structure, Patent Document 1 employs a structure in which a stop pin is attached to the output shaft and the stop pin slides in a groove on the housing side.
特開２０１３－２４３６０号公報JP 2013-24360 A
　特許文献１に記載された技術では、ストップピンがハウジングのフランジ部分内側に接触することで、出力軸がそれ以上突出できなくなる。この状態において、ストップピンはハウジングのフランジ内側の部分に線接触する。このため、使用を重ねるに従いストップピンが上記のフランジ内側に食い込み、当該フランジ内側の部分の変形や摩耗が生じる。この結果、出力軸の可動範囲にずれが生じ、リニアアクチュエータとしての精度が低下する。 In the technology described in Patent Document 1, the output shaft cannot protrude any more because the stop pin contacts the inside of the flange portion of the housing. In this state, the stop pin makes line contact with the inner portion of the housing flange. For this reason, as the use is repeated, the stop pin bites into the inside of the flange, and deformation and wear of the inside of the flange occur. As a result, a shift occurs in the movable range of the output shaft, and the accuracy as a linear actuator decreases.
　上記問題を解決する方法として、金属製のワッシャをストップピンとフランジ内側の位置に配置する方法があるが、部品点数の増加、ワッシャとストップピンの接触に伴う異音の発生、緩和されるとはいえ上記の線接触に起因するワッシャの変形や摩耗の問題がある。 As a method of solving the above problem, there is a method of arranging a metal washer at a position inside the stop pin and the flange, but the increase in the number of parts, the generation of noise due to the contact between the washer and the stop pin, and the relief No, there is a problem of washer deformation and wear due to the above-mentioned line contact.
　また、別の問題として、ストッピンがハウジング内側の溝内を摺動する際に、棒状のストップピンが溝の内側に点接触し、このストップピンによって溝の内側が削られる問題がある。ストップピンが摺動する溝の内側が削られると、その削られた分、出力軸が回転できるクリアランスが生じる。このクリアランスは、モータの回転角が出力軸の進出長に正確に反映されない要因となり、リニアアクチュエータの精度が低下する。 As another problem, when the stop pin slides in the groove inside the housing, there is a problem that the rod-shaped stop pin makes point contact with the inside of the groove and the inside of the groove is scraped by the stop pin. When the inner side of the groove in which the stop pin slides is cut, a clearance that allows the output shaft to rotate is generated. This clearance becomes a factor in which the rotation angle of the motor is not accurately reflected in the advance length of the output shaft, and the accuracy of the linear actuator decreases.
　このような背景において、本発明は、ロータの回転を出力軸の直線運動に変換する構造のリニアアクチュエータにおいて、出力軸の回転を防止し、且つ、軸方向に可動させる構造における出力軸の可動精度を高くできる技術の提供を目的とする。 Against this background, the present invention provides a linear actuator having a structure that converts the rotation of the rotor into a linear motion of the output shaft, and prevents the output shaft from rotating and is movable in the axial direction. The purpose is to provide technology that can improve
　本発明は、ハウジングと、前記ハウジングに回転可能な状態で保持されたロータと、前記ロータの回転に伴って前記ロータの回転方向とは異なる軸方向に移動可能な出力軸と、前記ハウジングに設けられた前記軸方向に延在する空間に配置され、前記軸方向と交差する第１の面を有する回り止め部材であって、前記空間の内部を前記軸方向に摺動可能であり、前記出力軸に固定された前記回り止め部材とを備え、前記ハウジングには、前記回り止め部材の前記第１の面が接触可能な第２の面が設けられたリニアアクチュエータである。 The present invention is provided with a housing, a rotor held rotatably in the housing, an output shaft movable in an axial direction different from the rotation direction of the rotor as the rotor rotates, and the housing A rotation-preventing member that is disposed in the axially extending space and has a first surface that intersects the axial direction, and is slidable in the axial direction inside the space; A non-rotating member fixed to a shaft, and the housing is a linear actuator provided with a second surface that can contact the first surface of the non-rotating member.
　本発明において、前記回り止め部材は、筒形状を有し、前記筒形状の外周面が前記空間の内周面に摺動可能な状態とされ、前記軸方向から見た前記回り止め部材の形状は、前記出力軸を回転中心とした３６０°以外の回転に対して非対称な形状を有する形態が挙げられる。 In the present invention, the anti-rotation member has a cylindrical shape, and an outer peripheral surface of the cylindrical shape is slidable on an inner peripheral surface of the space, and the shape of the anti-rotation member viewed from the axial direction. Is a form having an asymmetric shape with respect to rotation other than 360 ° with the output shaft as the rotation center.
　本発明において、前記回り止め部材の外周面は、第１の曲率を有する第１の曲面と、第２の曲率を有する第２の曲面と、前記第１の曲面と前記第２の曲面とを直接、あるいは段差を介してつなぐ２つの平面とにより構成されている形態が挙げられる。 In the present invention, the outer peripheral surface of the rotation preventing member includes a first curved surface having a first curvature, a second curved surface having a second curvature, the first curved surface, and the second curved surface. The form comprised by two planes connected directly or through a level | step difference is mentioned.
　本発明において、前記回り止め部材は、樹脂により構成され、前記出力軸には、前記軸方向に交差する方向に貫通した孔が設けられ、前記回り止め部材を構成する前記樹脂が前記孔の内部に充填された状態で、前記回り止め部材が前記出力軸に固定され、前記孔の向きと前記非対称な形状とに特定の関係がある形態が挙げられる。 In the present invention, the anti-rotation member is made of resin, and the output shaft is provided with a hole penetrating in a direction intersecting the axial direction, and the resin constituting the anti-rotation member is inside the hole. In such a state, the anti-rotation member is fixed to the output shaft in a state where the hole is filled, and there is a specific relationship between the direction of the hole and the asymmetric shape.
　本発明において、前記ロータは第１のねじ構造を備え、前記出力軸は前記第１のねじ構造と噛み合った第２のねじ構造を備え、前記出力軸における前記回り止め部材の位置と、前記第１のねじ構造と前記第２のねじ構造における歯の噛合い位置との関係が特定の関係に設定されている形態が挙げられる In the present invention, the rotor has a first screw structure, the output shaft has a second screw structure meshed with the first screw structure, the position of the detent member on the output shaft, and the first There is a form in which the relationship between the screw structure of 1 and the tooth meshing position in the second screw structure is set to a specific relationship.
　本発明によれば、ロータの回転を出力軸の直線運動に変換する構造のリニアアクチュエータにおいて、出力軸の回転を防止し、且つ、軸方向に可動させる構造における出力軸の可動精度を高くできる技術が提供される。 According to the present invention, in a linear actuator having a structure that converts rotation of a rotor into linear motion of an output shaft, it is possible to prevent rotation of the output shaft and increase the accuracy of movement of the output shaft in a structure that is movable in the axial direction. Is provided.
実施形態のリニアアクチュエータの斜視図である。It is a perspective view of the linear actuator of an embodiment. 実施形態のリニアアクチュエータの分解斜視図である。It is a disassembled perspective view of the linear actuator of embodiment. 実施形態のリニアアクチュエータの断面図である。It is sectional drawing of the linear actuator of embodiment. 実施形態におけるボビンの斜視図である。It is a perspective view of the bobbin in an embodiment. 実施形態における他のボビンの斜視図である。It is a perspective view of the other bobbin in an embodiment. 実施形態におけるステータ構造体にフロントプレート装着した状態を示す斜視図である。It is a perspective view which shows the state which attached the front plate to the stator structure in embodiment. 実施形態におけるステータ構造体にフロントプレート装着した状態を示す正面図である。It is a front view which shows the state which attached the front plate to the stator structure in embodiment. 実施形態のフロントハウジングの斜視図である。It is a perspective view of the front housing of an embodiment. 実施形態のフロントハウジングの正面図である。It is a front view of the front housing of an embodiment. 回り止め部材を装着したシャフトの斜視図である。It is a perspective view of the shaft which equipped the rotation prevention member. 回り止め部材を装着したシャフトの側断面図である。It is a sectional side view of the shaft which equipped the rotation prevention member. 回り止め部材を固定したシャフトの断面図である。It is sectional drawing of the shaft which fixed the rotation prevention member. ハウジングを構成する内側柱状空間の拡大図である。It is an enlarged view of the inner side columnar space which comprises a housing. 回り止め部材を装着したシャフトの側断面図である。It is a sectional side view of the shaft which equipped the rotation prevention member.
（構成）
　図１には、実施形態のリニアアクチュエータ１００が示されている。図２には、リニアアクチュエータ１００の斜視分解図が示されている。図３には、リニアアクチュエータ１００の断面図（軸に沿って切断した断面の図）が示されている。 (Constitution)
FIG. 1 shows a linear actuator 100 according to an embodiment. FIG. 2 shows an exploded perspective view of the linear actuator 100. FIG. 3 shows a sectional view of the linear actuator 100 (a sectional view taken along the axis).
　リニアアクチュエータ１００は、軸方向に端面１１５ａを有するステータヨーク１１５と、ステータヨーク１１５の内側に配置され、コイル１１１が巻かれたボビン１１３（図４Ａ参照）と、ステータヨーク１１５の端面１１５ａに固定されたフロントプレート１２０と、フロントプレート１２０と結合したフロントハウジング１５０とを備え、ボビン１１３にはフロントプレート１２０に設けられた孔１２１（図２，図５Ａ参照）に挿入されるボス部１４が設けられ、フロントハウジング１５０にはフロントプレート１２０に設けられた孔１２３に挿入されるボス部１５２（図６Ａ及び図６Ｂ参照）が設けられ、ボス部１５２の先端がステータヨーク１１５の端面１１５ａに接触している構造を有する。なお、軸方向というのは、図のＺ軸の方向であり、後述するシャフト１４０の延在方向として定義される。 The linear actuator 100 is fixed to a stator yoke 115 having an end surface 115a in the axial direction, a bobbin 113 (see FIG. 4A) around which the coil 111 is wound, and an end surface 115a of the stator yoke 115. The front plate 120 and the front housing 150 coupled to the front plate 120 are provided. The bobbin 113 is provided with a boss portion 14 to be inserted into a hole 121 (see FIGS. 2 and 5A) provided in the front plate 120. The front housing 150 is provided with a boss 152 (see FIGS. 6A and 6B) to be inserted into the hole 123 provided in the front plate 120, and the tip of the boss 152 comes into contact with the end surface 115a of the stator yoke 115. Has a structure. The axial direction is the direction of the Z axis in the figure, and is defined as the extending direction of the shaft 140 described later.
　以下、リニアアクチュエータ１００について詳細に説明する。図２に示すように、リニアアクチュエータ１００は、ステータ構造体１１０、フロントプレート１２０、ロータ１３０、シャフト１４０、フロントハウジング１５０、先端部１４２を有している。 Hereinafter, the linear actuator 100 will be described in detail. As shown in FIG. 2, the linear actuator 100 includes a stator structure 110, a front plate 120, a rotor 130, a shaft 140, a front housing 150, and a tip portion 142.
　ステータ構造体１１０は、略円筒形状を有し、クローポール型のステッピングモータのステータ構造を有している。ステータ構造体１１０は、コイル１１１および１１２（図３参照）、ボビン１１３および１１４、電磁鋼板等の軟磁性金属材料で構成されたステータヨーク１１５，１１７およびステータヨーク１１６および１１８を備え、内部の隙間に樹脂１１９（図３，図５Ａ参照）が充填され一体化されている。ここで、ステータヨーク１１５と１１７が組となり第１のクローポール型モータのステータヨークを構成し、ステータヨーク１１６と１１８が組となり第２のクローポール型モータのステータヨークを構成する。一般にステータヨーク１１５と１１６が外ヨーク、ステータヨーク１１７と１１８が内ヨークと呼ばれる。 The stator structure 110 has a substantially cylindrical shape and a claw pole type stepping motor stator structure. Stator structure 110 includes coils 111 and 112 (see FIG. 3), bobbins 113 and 114, stator yokes 115 and 117 made of a soft magnetic metal material such as an electromagnetic steel plate, and stator yokes 116 and 118, and an internal gap. The resin 119 (see FIGS. 3 and 5A) is filled and integrated. Here, the stator yokes 115 and 117 constitute a pair and constitute a stator yoke of the first claw pole type motor, and the stator yokes 116 and 118 constitute a pair and constitute a stator yoke of the second claw pole type motor. Generally, the stator yokes 115 and 116 are called outer yokes, and the stator yokes 117 and 118 are called inner yokes.
　コイル１１１は、界磁コイルを構成し、樹脂製のボビン１１３（図４Ａ参照）に巻かれている。コイル１１１が巻かれたボビン１１３は、ステータ構造体１１０（ステータヨーク１１５）の内側に収納されている。ボビン１１３は、樹脂を用いた射出成法により製造されており、円筒部１１（図４Ａ参照）、円筒部１１の軸方向両端の縁から径外側方向に延在したフランジ部１２，１３を備えている。 The coil 111 forms a field coil and is wound around a resin bobbin 113 (see FIG. 4A). The bobbin 113 around which the coil 111 is wound is housed inside the stator structure 110 (stator yoke 115). The bobbin 113 is manufactured by an injection molding method using a resin, and includes a cylindrical portion 11 (see FIG. 4A), and flange portions 12 and 13 extending radially outward from both ends of the cylindrical portion 11 in the axial direction. ing.
　一方のフランジ部１２には、軸方向に突出する突状の部分である３つのボス部１４が設けられている。ボス部１４は、等角度間隔（１２０°毎）の位置に設けられている。ボス部１４は、射出成形法によりボビン１１３と同時にボビン１１３の一部として形成されている。ボビン１１３の上部には、端子ピン１２５（図３参照）を固定する穴１５が形成されている。穴１５に固定された端子ピン１２５（図３参照）にコイル１１１から引き出されたリード線が接続される。 One flange portion 12 is provided with three boss portions 14 that are protruding portions protruding in the axial direction. The boss portions 14 are provided at positions at equal angular intervals (every 120 °). The boss portion 14 is formed as a part of the bobbin 113 simultaneously with the bobbin 113 by an injection molding method. A hole 15 for fixing the terminal pin 125 (see FIG. 3) is formed in the upper portion of the bobbin 113. A lead wire drawn from the coil 111 is connected to a terminal pin 125 (see FIG. 3) fixed to the hole 15.
　ステータヨーク１１５は、外側円筒部、内側歯部、外側円筒部と内側歯部をつなぐ板状の平板リング部（この平板リング部の裏面がステータヨーク１１５の端面１１５ａである）を有している。上記外側円筒部と内側歯部の間にコイル１１１が巻かれたボビン１１３が収容されている。ステータヨーク１１５の内側歯部は、軸方向（エンドハウジング１７０の方向）に延在する複数の第１の歯１１５ｂ（図３，図５Ａ参照）を有している。 The stator yoke 115 has an outer cylindrical portion, an inner tooth portion, and a plate-shaped flat ring portion connecting the outer cylindrical portion and the inner tooth portion (the back surface of the flat ring portion is the end surface 115a of the stator yoke 115). . A bobbin 113 around which a coil 111 is wound is accommodated between the outer cylindrical portion and the inner tooth portion. The inner tooth portion of the stator yoke 115 has a plurality of first teeth 115b (see FIGS. 3 and 5A) extending in the axial direction (direction of the end housing 170).
　ステータヨーク１１７は、ステータヨーク１１５と組みとなる部材であり、板状の平板リング部、この平板リング部の内縁から軸方向に延在する複数の第２の歯１１７ｂ（図５Ａ参照：図３では見えていない）を備えている。図５Ａに示すように、複数の第１の歯１１５ｂと複数の第２の歯１１７ｂは、互いに逆方向に延在し、且つ、互い違いに隙間を有した状態で噛合う位置関係とされている。この点は、通常のクローポール型のモータの場合と同じである。第１の歯１１５ｂと第２の歯１１７ｂの隙間は、ステータ構造体１１０の内部に充填された樹脂１１９により埋められている。 The stator yoke 117 is a member paired with the stator yoke 115, and has a plate-shaped flat ring portion and a plurality of second teeth 117b extending in the axial direction from the inner edge of the flat plate ring portion (see FIG. 5A: FIG. 3). Is not visible). As shown in FIG. 5A, the plurality of first teeth 115b and the plurality of second teeth 117b extend in directions opposite to each other and are in a positional relationship in which they are engaged with each other with a gap therebetween. . This is the same as in the case of a normal claw pole type motor. A gap between the first teeth 115b and the second teeth 117b is filled with a resin 119 filled in the stator structure 110.
　ボビン１１４も樹脂製であり、コイル１１２が巻かれている。ステータヨーク１１６と１１８は、ステータヨーク１１５の側と同様に、内周側において、複数の歯が互い違いに隙間を有した状態で噛合う位置関係の構造を有している。ステータヨーク１１６の歯とステータヨーク１１８の歯の間は、ステータ構造体１１０の内部に充填された樹脂１１９により埋められている。 The bobbin 114 is also made of resin, and the coil 112 is wound around it. As with the stator yoke 115 side, the stator yokes 116 and 118 have a positional relationship structure in which a plurality of teeth are engaged with each other in a state of having gaps alternately. A space between the teeth of the stator yoke 116 and the teeth of the stator yoke 118 is filled with a resin 119 filled in the stator structure 110.
　ステータヨーク１１５の端面１１５ａには、ボビン１１３のボス部１４が挿入され貫通する３つの孔１１５ｃ（図３参照）が設けられ、この３つの孔１１５ｃにボス部１４が挿入されている。孔１１５ｃに挿入されたボス部１４の先端は、孔１１５ｃからフロントハウジング１５０の側に突出している。 The end face 115a of the stator yoke 115 is provided with three holes 115c (see FIG. 3) through which the boss part 14 of the bobbin 113 is inserted, and the boss part 14 is inserted into the three holes 115c. The tip of the boss portion 14 inserted into the hole 115c protrudes from the hole 115c to the front housing 150 side.
　図５Ａおよび図５Ｂには、ステータヨーク１１５（ステータ構造体１１０）にフロントプレート１２０を取りつけた状態が示されている。フロントプレート１２０は、金属製であり、ステータヨーク１１５に溶接により固定されている。 5A and 5B show a state in which the front plate 120 is attached to the stator yoke 115 (stator structure 110). The front plate 120 is made of metal and is fixed to the stator yoke 115 by welding.
　フロントプレート１２０は、ステータヨーク１１５から軸方向に突出した３つのボス部１４が嵌る３つの孔１２１が設けられている。３か所のボス部１４が３か所の孔１２１に嵌ることで、ステータヨーク１１５に対するフロントプレート１２０の位置決めが行われている。 The front plate 120 is provided with three holes 121 into which the three boss portions 14 protruding in the axial direction from the stator yoke 115 are fitted. The front plate 120 is positioned with respect to the stator yoke 115 by fitting the three boss portions 14 into the three holes 121.
　フロントプレート１２０は、先端に開口１２２ａのある固定用腕部１２２を３か所に備えている。固定用腕部１２２は、フロントプレート１２０とフロントハウジング１５０とを結合させる部材であり、フロントプレート１２０にフロントハウジング１５０を支持させる支持部として機能する。図１に示すように、固定用腕部１２２を変形させてフロントハウジング１５０の突起１５１に開口１２２ａ（図２参照）を係合させることで、フロントプレート１２０がフロントハウジング１５０に結合している。 The front plate 120 is provided with three fixing arm portions 122 having openings 122a at the tips. The fixing arm portion 122 is a member that couples the front plate 120 and the front housing 150, and functions as a support portion that supports the front housing 150 on the front plate 120. As shown in FIG. 1, the front plate 120 is coupled to the front housing 150 by deforming the fixing arm portion 122 and engaging the opening 122 a (see FIG. 2) with the protrusion 151 of the front housing 150.
　フロントハウジング１５０の斜視図を図６Ａに、正面図を図６Ｂにそれぞれ示す。フロントハウジング１５０は、樹脂製であり、射出成形法によって形成されている。フロントハウジング１５０には、軸方向に突出する突状の部分である３つのボス部１５２が設けられている。ボス部１５２は、樹脂を用いた射出成形法により製造されるが、この製造時にボス部１５２もフロントハウジング１５０の一部として同時に形成される。 FIG. 6A is a perspective view of the front housing 150, and FIG. 6B is a front view thereof. The front housing 150 is made of resin and is formed by an injection molding method. The front housing 150 is provided with three boss portions 152 that are protruding portions protruding in the axial direction. The boss portion 152 is manufactured by an injection molding method using a resin, and the boss portion 152 is simultaneously formed as a part of the front housing 150 at the time of manufacturing.
　ボス部１５２は、フロントプレート１２０に設けられた孔１２３に挿入され、孔１２３の内側を通過している。孔１２３の底の部分はステータヨーク１１５の軸方向の端面１１５ａが露呈しており（図５Ａ参照）、ボス部１５２の先端がステータヨーク１１５の軸方向の端面１１５ａに接触する。この構造により、フロントハウジング１５０とステータ構造体１１０との軸方向における相対位置関係が決められている。なお、ボビン１１３に設けられたボス部１４の突出長は、その先端がフロントハウジング１５０と接触しない寸法に設定されている。この例で、孔１２１から先端が突出しない寸法にボス部１４のボビン１１３端面からの突出長が設定されている。 The boss portion 152 is inserted into the hole 123 provided in the front plate 120 and passes through the inside of the hole 123. The bottom portion of the hole 123 exposes the axial end surface 115a of the stator yoke 115 (see FIG. 5A), and the tip of the boss 152 contacts the axial end surface 115a of the stator yoke 115. With this structure, the relative positional relationship in the axial direction between the front housing 150 and the stator structure 110 is determined. The protruding length of the boss portion 14 provided on the bobbin 113 is set to a dimension such that the tip thereof does not contact the front housing 150. In this example, the protruding length of the boss portion 14 from the end surface of the bobbin 113 is set to a dimension that does not protrude from the hole 121.
　図２および図３に示すように、ステータ構造体１１０の内側には、ロータ１３０が回転可能な状態で保持されている。ロータ１３０は、内側円筒部材１３１、内側円筒部材１３１の外側に固定された円筒形状のロータマグネット１３２、内側円筒部材１３１の内側に固定された内周に雌ねじ構造が形成された円筒形状の雌ねじ１３３を有している。ロータマグネット１３２は、周方向に沿って交互にＮＳＮＳ・・と着磁された永久磁石である。雌ねじ１３３は、細長い円柱形状のシャフト１４０の外周に形成された雄ねじ構造１４１に噛合っている。 2 and 3, the rotor 130 is held inside the stator structure 110 in a rotatable state. The rotor 130 includes an inner cylindrical member 131, a cylindrical rotor magnet 132 fixed to the outside of the inner cylindrical member 131, and a cylindrical female screw 133 having a female screw structure formed on the inner periphery fixed to the inner side of the inner cylindrical member 131. have. The rotor magnet 132 is a permanent magnet that is alternately magnetized with NSNS... Along the circumferential direction. The internal thread 133 meshes with an external thread structure 141 formed on the outer periphery of an elongated cylindrical shaft 140.
　ロータ１３０を構成する内側円筒部材１３１は、玉軸受１３４，１３５により回転自在な状態で保持されている。より詳細には、玉軸受１３４の外輪は、ステータヨーク１１６に固定されたエンドハウジング１７０に固定されており、玉軸受１３４の内輪は、ロータ１３０を構成する内側円筒部材１３１に固定されている（玉軸受１３４の外輪は、エンドハウジング１７０に接触しているが、ロータ１３０には接触していない）。玉軸受１３５の外輪は、フロントハウジング１５０に固定されており、玉軸受１３５の内輪は、ロータ１３０を構成する内側円筒部材１３１に固定されている（玉軸受１３５の外輪は、フロントハウジング１５０に接触しているが、ロータ１３０には接触していない）。すなわち、ロータ１３０は、エンドハウジング１７０とフロントハウジング１５０に対して玉軸受１３４，１３５により回転自在な状態で保持されている。 The inner cylindrical member 131 constituting the rotor 130 is held in a freely rotatable state by ball bearings 134 and 135. More specifically, the outer ring of the ball bearing 134 is fixed to an end housing 170 fixed to the stator yoke 116, and the inner ring of the ball bearing 134 is fixed to an inner cylindrical member 131 constituting the rotor 130 ( The outer ring of the ball bearing 134 is in contact with the end housing 170 but not the rotor 130). The outer ring of the ball bearing 135 is fixed to the front housing 150, and the inner ring of the ball bearing 135 is fixed to the inner cylindrical member 131 constituting the rotor 130 (the outer ring of the ball bearing 135 is in contact with the front housing 150. But not in contact with the rotor 130). That is, the rotor 130 is held in a freely rotatable state by the ball bearings 134 and 135 with respect to the end housing 170 and the front housing 150.
　シャフト１４０の先端には、先端部１４２がピン１４４によって固定されている。図７Ａ及び図７Ｂには、出力軸となるシャフト１４０が示されている。シャフト１４０には、回り止め部材１４３が固定されている。回り止め部材１４３は、略筒形状を有し、樹脂製で射出成形によりシャフト１４０に一体成型により組み付けられている。シャフト１４０には、軸方向に垂直な方向に貫通する孔１４０ａが設けられ、この孔１４０ａの中に回り止め部材１４３を構成する樹脂１４３ｄが入り込むように、回り止め部材１４３が形成されている。こうすることで、簡素な構造でありながら、シャフト１４０に回り止め部材１４３が強固に固定される。
　なお、回り止め部材１４３を構成する材料は樹脂に限られたものではなく、例えば、図１０において後述する焼結部材であっても構わない。 A distal end portion 142 is fixed to the distal end of the shaft 140 by a pin 144. 7A and 7B show a shaft 140 serving as an output shaft. A rotation preventing member 143 is fixed to the shaft 140. The anti-rotation member 143 has a substantially cylindrical shape, and is made of resin and assembled to the shaft 140 by integral molding by injection molding. The shaft 140 is provided with a hole 140a penetrating in a direction perpendicular to the axial direction, and the anti-rotation member 143 is formed so that the resin 143d constituting the anti-rotation member 143 enters the hole 140a. By doing so, the anti-rotation member 143 is firmly fixed to the shaft 140 with a simple structure.
In addition, the material which comprises the rotation prevention member 143 is not restricted to resin, For example, the sintered member mentioned later in FIG. 10 may be sufficient.
　回り止め部材１４３の軸方向における一方側の端部が面状の端面１４３ｂ（第１の面）とされており、他方側の端部が端面１４３ｃとされている。端面１４３ｂ、１４３ｃは、軸方向に垂直な平面である。この構造では、端面１４３ｂが内側フランジ部１５４の接触面１５４ａ（第２の面）に接触することで、シャフト１４０がそれ以上フロントハウジング１５０から突出しない状態となる。端面１４３ｂに軸方向で対向する内側フランジ部１５４の接触面１５４ａも軸方向に垂直な平面であり、上記の端面１４３ｂと内側フランジ部１５４の接触面１５４ａとの接触は面での接触となる。 One end in the axial direction of the anti-rotation member 143 is a planar end surface 143b (first surface), and the other end is an end surface 143c. The end faces 143b and 143c are planes perpendicular to the axial direction. In this structure, the end surface 143b contacts the contact surface 154a (second surface) of the inner flange portion 154, so that the shaft 140 does not protrude from the front housing 150 any more. The contact surface 154a of the inner flange portion 154 facing the end surface 143b in the axial direction is also a plane perpendicular to the axial direction, and the contact between the end surface 143b and the contact surface 154a of the inner flange portion 154 is a surface contact.
　図７Ｂには、シャフト１４０に取りつけられた状態の回り止め部材１４３の軸方向に垂直な断面の形状が示されている。図８には、軸方向から見た回り止め部材１４３の形状が、シャフト１４０を回転中心とした３６０°以外の回転に対して非対称な形状の一例が示されている。この例における回り止め部材１４３の外周面は、上側曲面１６１、下側曲面１６２、上側曲面１６１と下側曲面１６２をつなぐ２つの側面１６３，１６４により構成されている。上側曲面１６１と下側曲面１６２は、曲率が異なる円筒曲面の一部であり、側面１６３，１６４は平面である。 FIG. 7B shows a cross-sectional shape perpendicular to the axial direction of the detent member 143 attached to the shaft 140. FIG. 8 shows an example of the shape of the anti-rotation member 143 as viewed from the axial direction that is asymmetric with respect to rotation other than 360 ° with the shaft 140 as the rotation center. The outer peripheral surface of the rotation preventing member 143 in this example includes an upper curved surface 161, a lower curved surface 162, and two side surfaces 163 and 164 that connect the upper curved surface 161 and the lower curved surface 162. The upper curved surface 161 and the lower curved surface 162 are part of cylindrical curved surfaces having different curvatures, and the side surfaces 163 and 164 are flat surfaces.
　ここで、側面１６３，１６４と下側曲面１６２とは直接、側面１６３，１６４と上側曲面１６１とは段差を介して、それぞれつながっている。なお、下側曲面１６２及び上側曲面１６１の双方ともが側面１６３，１６４と直接つながって、側面１６３と側面１６４とが平行になっていなくても構わない。その場合には、後述する柱状空間１５３の内面の断面形状を、回り止め部材１４３の断面形状に対応した形状とすればよい。 Here, the side surfaces 163 and 164 and the lower curved surface 162 are directly connected to each other through a step between the side surfaces 163 and 164 and the upper curved surface 161. Note that both the lower curved surface 162 and the upper curved surface 161 may be directly connected to the side surfaces 163 and 164, and the side surface 163 and the side surface 164 may not be parallel to each other. In that case, the cross-sectional shape of the inner surface of the columnar space 153 described later may be a shape corresponding to the cross-sectional shape of the rotation preventing member 143.
　フロントハウジング１５０は、軸方向に延在する円筒部１５６を有し、円筒部１５６の内側には、シャフト１４０および回り止め部材１４３が収まる柱形状の空間である柱状空間１５３が設けられている。柱状空間１５３は、軸方向に垂直な断面が、回り止め部材１４３の断面形状に対応した形状に設定されている。図９には、軸方向から見た柱状空間１５３の断面の形状が示されている。図９に示すように、軸方向から見た柱状空間１５３の内面は、上側曲面１７１、下側曲面１７２、上側曲面１７１と下側曲面１７２をつなぐ平面である２つの側面１７３，１７４で構成されている。 The front housing 150 has a cylindrical portion 156 extending in the axial direction, and a columnar space 153 that is a columnar space in which the shaft 140 and the rotation preventing member 143 are accommodated is provided inside the cylindrical portion 156. In the columnar space 153, the cross section perpendicular to the axial direction is set to a shape corresponding to the cross sectional shape of the rotation preventing member 143. FIG. 9 shows a cross-sectional shape of the columnar space 153 viewed from the axial direction. As shown in FIG. 9, the inner surface of the columnar space 153 viewed from the axial direction is composed of an upper curved surface 171, a lower curved surface 172, and two side surfaces 173 and 174 that are planes connecting the upper curved surface 171 and the lower curved surface 172. ing.
　上側曲面１７１は、回り止め部材１４３の上側曲面１６１に摺動可能な状態で接触する、あるいは上側曲面１７１と上側曲面１６１とは、所定の間隔を隔てて離間している。下側曲面１７２は、回り止め部材１４３の下側曲面１６２に摺動可能な状態で接触する、あるいは上側曲面１７２と上側曲面１６２とは、所定の間隔を隔てて離間している。側面１７３は、回り止め部材１４３の側面１６３に摺動可能な状態で接触する。側面１７４は、回り止め部材１４３の側面１６４に摺動可能な状態で接触する。すなわち、回り止め部材１４３の寸法と柱状空間１５３の寸法は、回り止め部材１４３が柱状空間１５３内で回転できず、且つ、摺動しつつ軸方向に移動できる関係に設定されている。 The upper curved surface 171 contacts the upper curved surface 161 of the rotation preventing member 143 in a slidable state, or the upper curved surface 171 and the upper curved surface 161 are separated from each other by a predetermined interval. The lower curved surface 172 contacts the lower curved surface 162 of the rotation preventing member 143 in a slidable state, or the upper curved surface 172 and the upper curved surface 162 are separated by a predetermined distance. The side surface 173 contacts the side surface 163 of the detent member 143 in a slidable state. The side surface 174 contacts the side surface 164 of the detent member 143 in a slidable state. That is, the dimension of the rotation preventing member 143 and the dimension of the columnar space 153 are set so that the rotation preventing member 143 cannot rotate in the columnar space 153 and can move in the axial direction while sliding.
　側面１７３と側面１６３の接触および側面１７４と側面１６４の接触の状態には、面接触となる第１の場合とそうでない第２の場合とがある。第１の場合、側面１７３と側面１６３は面接触し、両者は相対的に摺動可能な状態にある。同様に、側面１７４と側面１６４は面接触し、両者は相対的に摺動可能な状態にある。この場合、高い寸法精度が要求される。 The contact state between the side surface 173 and the side surface 163 and the contact state between the side surface 174 and the side surface 164 include a first case where surface contact is made and a second case where contact is not made. In the first case, the side surface 173 and the side surface 163 are in surface contact with each other and are in a slidable state. Similarly, the side surface 174 and the side surface 164 are in surface contact with each other and are in a slidable state. In this case, high dimensional accuracy is required.
　第２の場合、側面１７３と側面１６３の間、および側面１７４と側面１６４の間には、数μｍ～数十μｍ幅程度の僅かな隙間が設けられ、柱状空間１５３に対して、回り止め部材１４３が移動可能な状態が実現される。この場合、回転しようとする回り止め部材１４３の外周面と柱状空間１５３の内周面とは、面の縁の部分での接触となるので、基本的に線接触となる。 In the second case, a slight gap having a width of several μm to several tens of μm is provided between the side surface 173 and the side surface 163 and between the side surface 174 and the side surface 164, and the rotation preventing member is provided with respect to the columnar space 153. A state in which 143 is movable is realized. In this case, the outer peripheral surface of the rotation preventing member 143 to be rotated and the inner peripheral surface of the columnar space 153 are in contact with each other at the edge portion of the surface, and thus are basically in line contact.
　上側曲面１６１の曲率と下側曲面１６２の曲率は異なる値に設定されている。これに対応して、上側曲面１７１の曲率と下側曲面１７２の曲率も異なる。この構造では、上側曲面１６１と１７１が対向し、下側曲面１６２と１７２が対向した状態でないと、回り止め部材１４３が柱状空間１５３内に収容できない。 The curvature of the upper curved surface 161 and the curvature of the lower curved surface 162 are set to different values. Correspondingly, the curvature of the upper curved surface 171 and the curvature of the lower curved surface 172 are also different. In this structure, the anti-rotation member 143 cannot be accommodated in the columnar space 153 unless the upper curved surfaces 161 and 171 face each other and the lower curved surfaces 162 and 172 face each other.
　フロントハウジング１５０からは、柱状空間１５３の一部を構成する円筒部１５６が延在しており、円筒部１５６の先端には内側フランジ部１５４が形成されている。内側フランジ部１５４の中心には孔が設けられ、この孔から出力軸であるシャフト１４０が外部に突出している。柱状空間１５３の一端側（図３の左側）は、内側フランジ部１５４で定義され、他端側（図３の右側）は、玉軸受１３５が収容される軸受収容空間１３５aで定義されている。軸受収容空間１３５aには、フロントハウジング１５０に形成された溝１５５が形成されている。この溝１５５は、玉軸受１３５の内輪の端面（図３の左側）が、フロントハウジング１５０に接触しないように、フロントハウジング１５０に形成されている。先端部１４２の外側方向（図３の左方向）への稼働範囲は、回り止め部材１４３が柱状空間１５３の内側フランジ部１５４に当たる事で決まり、内側方向（図３の右方向）への可動範囲は、先端部１４２が柱状空間１５３の内側フランジ部１５４に当たる事で決まる。 A cylindrical portion 156 that constitutes a part of the columnar space 153 extends from the front housing 150, and an inner flange portion 154 is formed at the tip of the cylindrical portion 156. A hole is provided at the center of the inner flange portion 154, and a shaft 140 that is an output shaft protrudes outside from the hole. One end side (left side in FIG. 3) of the columnar space 153 is defined by an inner flange portion 154, and the other end side (right side in FIG. 3) is defined by a bearing housing space 135a in which the ball bearing 135 is housed. A groove 155 formed in the front housing 150 is formed in the bearing housing space 135a. The groove 155 is formed in the front housing 150 so that the end surface (the left side in FIG. 3) of the inner ring of the ball bearing 135 does not contact the front housing 150. The operating range of the distal end portion 142 in the outer direction (left direction in FIG. 3) is determined by the rotation preventing member 143 coming into contact with the inner flange portion 154 of the columnar space 153, and the movable range in the inner direction (right direction in FIG. 3). Is determined by the front end portion 142 hitting the inner flange portion 154 of the columnar space 153.
（動作）
　コイル１１１と１１２に電流を流すと、ステータヨーク１１５とステータヨーク１１７の歯の間、すなわち図５Ａにおける複数の第１の歯１１５ｂと複数の第２の歯１１７ｂの間に周方向の成分を有する磁界が発生する。また、同様にステータヨーク１１６とステータヨーク１１８の歯の間に周方向の成分を有する磁界が発生する。そして上記の駆動電流の正負を特定のタイミングで切り替えると上記の磁界の向きが周期的に切り替わり、ロータマグネット１３２を回転させる駆動力が発生する。 (Operation)
When a current is passed through the coils 111 and 112, there is a circumferential component between the teeth of the stator yoke 115 and the stator yoke 117, that is, between the plurality of first teeth 115b and the plurality of second teeth 117b in FIG. 5A. Magnetic field is generated. Similarly, a magnetic field having a circumferential component is generated between the teeth of the stator yoke 116 and the stator yoke 118. When the polarity of the driving current is switched at a specific timing, the direction of the magnetic field is periodically switched, and a driving force for rotating the rotor magnet 132 is generated.
　上記の駆動力によりロータ１３０と雌ねじ１３３が一体となって回転する。ここで、シャフト１４０は回り止め部材１４３によって回転できず、他方で軸方向には移動可能であるので、雌ねじ１３３が回転することで、雌ねじ１３３と噛み合った雄ねじ構造１４１を有するシャフト１４０は、軸方向に進退する。シャフト１４０の移動方向は、ロータ１３０の回転方向によって決まる。シャフト１４０が軸方向に動くことで、先端部１４２が軸方向に動く。 The rotor 130 and the internal thread 133 are rotated together by the above driving force. Here, since the shaft 140 cannot be rotated by the anti-rotation member 143 and is movable in the axial direction, the shaft 140 having the male screw structure 141 meshed with the female screw 133 is rotated by the rotation of the female screw 133. Advance and retreat in the direction. The moving direction of the shaft 140 is determined by the rotating direction of the rotor 130. As the shaft 140 moves in the axial direction, the distal end portion 142 moves in the axial direction.
（特徴的な構造１）
　リニアアクチュエータ１００は、フロントハウジング１５０と、フロントハウジング１５０に回転可能な状態で保持され、内側に雌ねじ１３３を有した筒形状のロータ１３０と、雌ねじ１３３と噛み合った雄ねじ構造を外周に備えたシャフト１４０と、フロントハウジング１５０に設けられた軸方向に延在する柱状空間１５３に納められ、フロントハウジング１５０に対して回転できず、且つ、柱状空間１５３の内部を軸方向（Ｚ軸方向）に摺動可能であり、シャフト１４０に固定された回り止め部材１４３とを備え、フロントハウジング１５０には、回り止め部材１４３の軸方向における端面１４３ｂが接触可能な接触面１５４ａが設けられ、シャフト１４０の突出が最大となった状態で、回り止め部材１４３の軸方向における端面１４３ｂがフロントハウジング１５０の接触面１５４ａに面接触する。 (Characteristic structure 1)
The linear actuator 100 is rotatably supported by the front housing 150, the front housing 150, the shaft-shaped rotor 130 having an internal thread 133 inside, and a shaft 140 provided on the outer periphery with an external thread structure meshed with the internal thread 133. Are accommodated in a columnar space 153 provided in the front housing 150 and extending in the axial direction, cannot rotate with respect to the front housing 150, and slide in the columnar space 153 in the axial direction (Z-axis direction). The front housing 150 is provided with a contact surface 154a that can contact the end surface 143b in the axial direction of the anti-rotation member 143 so that the shaft 140 protrudes. In the maximum state, the end face 143 in the axial direction of the anti-rotation member 143 There is in surface contact with the contact surface 154a of the front housing 150.
　上記構造では、シャフト１４０が最大伸長時に回り止め部材１４３とフロントハウジング１５０の内側フランジ部１５４とが面接触するので、接触部分の摩耗や変形の発生が抑制される。なお、本実施形態の構造では、回り止め部材１４３と内側フランジ部１５４との間の耐久性を上げるためのワッシャは不要であるが、当該ワッシャの利用を排除するものではない。 In the above structure, since the rotation preventing member 143 and the inner flange portion 154 of the front housing 150 are in surface contact when the shaft 140 is extended to the maximum, wear and deformation of the contact portion are suppressed. In the structure of the present embodiment, a washer for increasing durability between the anti-rotation member 143 and the inner flange portion 154 is not necessary, but use of the washer is not excluded.
（特徴的な構造２）
　回り止め部材１４３は、全体として筒形状を有し、この筒形状の外周面が柱状空間１５３の内周面に対して相対的に摺動可能な状態とされ、軸方向から見た回り止め部材１４３の形状は、シャフト１４０を回転中心とした３６０°の回転に対して対称で、３６０°以外の回転に対して非対称な形状を有する。特に、前記回り止め部材１４３の外周面は、第１の曲率を有する上側曲面１６１と、上側曲面１６１と曲率が異なる第２の曲率を有する下側曲面１６２と、上側曲面１６１と下側曲面１６２とを直接乃至段差を介してつなぐ２つの平面１６３，１６４とにより構成されている。 (Characteristic structure 2)
The anti-rotation member 143 has a cylindrical shape as a whole, and the cylindrical outer peripheral surface is slidable relative to the inner peripheral surface of the columnar space 153, and the anti-rotation member viewed from the axial direction. The shape of 143 is symmetric with respect to 360 ° rotation about the shaft 140 as the rotation center, and is asymmetric with respect to rotation other than 360 °. In particular, the outer peripheral surface of the anti-rotation member 143 includes an upper curved surface 161 having a first curvature, a lower curved surface 162 having a second curvature different from the upper curved surface 161, and an upper curved surface 161 and a lower curved surface 162. Are formed by two planes 163 and 164 that directly connect each other through a step.
　上記の構造では、シャフト１４０の軸方向への進退時に回り止め部材１４３の外周面と、円筒部１５６の内周面（柱状空間１５３の内周面）とが接触し、この状態で回り止め部材１４３が円筒部１５６の内周面に対して摺動する。この際の接触は、面接触または線接触であり、当該摺動の際に、特定の部分に強い力が加わることがなく、円筒部１５６の内周面および回り止め部材１４３の一方または両方に摩耗が生じ難い。このため、円筒部１５６と回り止め部材１４３の間の摩耗に起因する隙間が生じ難い。この隙間が生じると、僅かであるが回り止め部材１４３の回転が許容され、リニアアクチュエータとしての精度が低下する。しかしながら、上記構成によれば、上記の隙間の発生が抑制されるので、精度の低下が抑えられる。 In the above structure, when the shaft 140 advances and retreats in the axial direction, the outer circumferential surface of the rotation preventing member 143 and the inner circumferential surface of the cylindrical portion 156 (inner circumferential surface of the columnar space 153) are in contact with each other. 143 slides with respect to the inner peripheral surface of the cylindrical portion 156. The contact at this time is a surface contact or a line contact, and a strong force is not applied to a specific portion during the sliding, and one or both of the inner peripheral surface of the cylindrical portion 156 and the rotation preventing member 143 are applied. Wear is difficult to occur. For this reason, the clearance gap resulting from abrasion between the cylindrical part 156 and the rotation prevention member 143 is hard to produce. When this gap occurs, the rotation preventing member 143 is allowed to rotate slightly, but the accuracy as a linear actuator is lowered. However, according to the above configuration, since the generation of the gap is suppressed, a decrease in accuracy can be suppressed.
　例えば、側面１７３と側面１６３の間、および側面１７４と側面１６４の間の状態が面接触または面接触とみなせる場合、接触面積が大きいので、上述した円筒部１５６の内周面および回り止め部材１４３の一方または両方に摩耗が生じ難い。 For example, when the state between the side surface 173 and the side surface 163 and between the side surface 174 and the side surface 164 can be regarded as surface contact or surface contact, the contact area is large, and thus the inner peripheral surface of the cylindrical portion 156 and the rotation preventing member 143 described above. One or both of them are less likely to wear.
　また、側面１７３と側面１６３の間、および側面１７４と側面１６４の間に隙間が設けられている場合、側面１７３と側面１６３および側面１７４と側面１６４とは基本的に線接触となるが、従来のストップピンによるハウジング内側への点による接触に比較すれば、接触面積は大きく、円筒部１５６の内周面および回り止め部材１４３の一方または両方における摩耗が抑えられる。 In addition, when a gap is provided between the side surface 173 and the side surface 163 and between the side surface 174 and the side surface 164, the side surface 173 and the side surface 163 and the side surface 174 and the side surface 164 are basically in line contact. Compared with the contact by the point inside the housing by the stop pin, the contact area is large, and wear on one or both of the inner peripheral surface of the cylindrical portion 156 and the anti-rotation member 143 is suppressed.
（特徴的な構造３）
　回り止め部材１４３は、樹脂により構成され、シャフト１４０には、軸に垂直な方向に貫通した孔１４０ａが設けられ、回り止め部材１４３を構成する樹脂が孔１４０ａの内部に充填された状態で、回り止め部材１４３がシャフト１４０に固定され、孔１４０ａの向きと回り止め部材１４３の非対称な形状とに特定の関係がある。 (Characteristic structure 3)
The anti-rotation member 143 is made of resin, the shaft 140 is provided with a hole 140a penetrating in a direction perpendicular to the axis, and the resin constituting the anti-rotation member 143 is filled in the hole 140a, The anti-rotation member 143 is fixed to the shaft 140, and there is a specific relationship between the direction of the hole 140a and the asymmetric shape of the anti-rotation member 143.
　軸方向から見た回り止め部材１４３の形状が上下非対称であるので、柱状空間１５３への挿入時における回り止め部材１４３の上下（Ｙ軸）方向の向きが一義的に決まる。つまり、回り止め部材１４３は、上下でひっくり返して（軸回りに１８０°回転させて）柱状空間１５３に挿入することはできない。すなわち、シャフト１４０を柱状空間１５３へ挿入する際に、予め決められた方向とは異なる方向にシャフト１４０が柱状空間１５３に挿入されてしまうという心配がない。 Since the shape of the anti-rotation member 143 as viewed from the axial direction is vertically asymmetric, the direction of the anti-rotation member 143 in the vertical (Y-axis) direction during insertion into the columnar space 153 is uniquely determined. That is, the anti-rotation member 143 cannot be inserted into the columnar space 153 by turning it upside down (rotating 180 degrees around the axis). That is, when the shaft 140 is inserted into the columnar space 153, there is no concern that the shaft 140 is inserted into the columnar space 153 in a direction different from a predetermined direction.
　仮に、シャフト１４０に取りつけた状態で回り止め部材１４３を上下でひっくり返して柱状空間１５３に挿入できる場合、雄ねじ構造１４１のねじ山半ピッチ分のずれが生じる。つまり、組み立て方によっては、ねじ山半ピッチ分の設定誤差が生じる。０．１ｍｍ単位といった精密な制御が要求される場合、上記の設定誤差が無視できない。図８の構造では、柱状空間１５３に挿入する際の上下の方向の向きが一義的に決まるので、上記のねじ山半ピッチ分の設定誤差が生じる問題が生じない。また、上記非対称な形状は、孔の向きで決まるので、孔の向きにより、このシャフトの回転位置が決まり、組み立て時の誤差の発生が抑えられる。 If the detent member 143 can be turned upside down and inserted into the columnar space 153 while attached to the shaft 140, the male thread structure 141 is displaced by a half pitch of the thread. That is, depending on the assembly method, a setting error corresponding to the half pitch of the thread occurs. When precise control such as 0.1 mm unit is required, the above setting error cannot be ignored. In the structure of FIG. 8, since the direction in the vertical direction when inserted into the columnar space 153 is uniquely determined, the above-described problem of setting errors corresponding to the half thread pitch does not occur. Further, since the asymmetric shape is determined by the direction of the hole, the rotational position of the shaft is determined by the direction of the hole, and the occurrence of errors during assembly can be suppressed.
（特徴的な構造４）
　回り止め部材１４３がフロントハウジング１５０（内側フランジ部１５４）の接触面１５４ａに接触した状態において、シャフト１４０における回り止め部材１４３の位置と、雄ねじ構造１４１と雌ねじ１３３における歯の噛合い位置との関係が特定の関係に設定されている。 (Characteristic structure 4)
The relationship between the position of the anti-rotation member 143 in the shaft 140 and the meshing position of the teeth in the male screw structure 141 and the internal screw 133 when the anti-rotation member 143 is in contact with the contact surface 154a of the front housing 150 (inner flange portion 154). Is set to a specific relationship.
　上述したように、回り止め部材１４３を取り付けたシャフト１４０の軸回りの回転位置が一義的であるので、回り止め部材１４３がフロントハウジング１５０の接触面１５４ａに接触した状態において、雄ねじ構造１４１と雌ねじ１３３における歯の噛合い位置と軸方向における回り止め部材１４３の位置の関係を精密に決めることができる。 As described above, the rotational position around the axis of the shaft 140 to which the anti-rotation member 143 is attached is unambiguous. Therefore, in the state where the anti-rotation member 143 contacts the contact surface 154a of the front housing 150, the male screw structure 141 and the female screw The relationship between the tooth meshing position at 133 and the position of the anti-rotation member 143 in the axial direction can be determined precisely.
　上記の優位性を具体的な例を挙げて説明する。本発明の基本構造を有するリニアアクチュエータの位置決め精度を追求した形態として、先端部１４２が特定の位置にある場合に、ステータヨークの歯（１１５ｂ、１１７ｂ）とロータマグネット１３２の磁極の位置を一致させた構造とする形態がある。この場合、各部の設計パラメータを調整し、組み上げた際に上記の条件が満たされるようにする。 The above advantages will be explained with specific examples. As a form pursuing the positioning accuracy of the linear actuator having the basic structure of the present invention, when the tip 142 is at a specific position, the teeth of the stator yoke (115b, 117b) and the magnetic pole position of the rotor magnet 132 are made to coincide. There are forms that have different structures. In this case, the design parameters of each part are adjusted so that the above conditions are satisfied when assembled.
　この際、回り止め部材１４３の上下をひっくり返しても、つまり１８０°回転させても柱状空間１５３に挿入できると、上記の設定に雄ネジ構造１４１のネジ山半ピッチ分の設定誤差が生じる。つまり、同じ製造条件であっても、位置決め精度に雄ネジ構造１４１のネジ山半ピッチ分の差があるものが含まれてしまう。 At this time, if the anti-rotation member 143 is turned upside down, that is, rotated 180 °, it can be inserted into the columnar space 153, a setting error corresponding to a half pitch of the thread of the male screw structure 141 occurs in the above setting. In other words, even under the same manufacturing conditions, the positioning accuracy includes a difference corresponding to a half pitch of the thread of the male screw structure 141.
　これに対して、本実施形態の回り止め部材１４３を取り付けたシャフト１４０の軸回りの回転位置が一義的である構造では、上記ネジ山半ピッチ分の差が生じず、高い位置決め精度を持った製品が製造できる。 On the other hand, in the structure in which the rotation position around the axis of the shaft 140 to which the anti-rotation member 143 of the present embodiment is attached is unambiguous, the difference corresponding to the half pitch of the thread does not occur, and high positioning accuracy is obtained. The product can be manufactured.
（その他）
　図１０には、シャフト１４０に回り止め部材１６０をピン１６１により固定した構造の例が示されている。ここで、回り止め部材１６０の外形形状は、回り止め部材１４３と同じである。回り止め部材１６０を構成する材料は、焼結部材である。 (Other)
FIG. 10 shows an example of a structure in which a rotation preventing member 160 is fixed to the shaft 140 with a pin 161. Here, the outer shape of the anti-rotation member 160 is the same as that of the anti-rotation member 143. The material constituting the rotation preventing member 160 is a sintered member.
　シャフト１４０を回転中心とした３６０°以外の回転に対して非対称な形状としては、台形や、三角形、五角形、七角形等の奇数角形（正多角形を除く）等が挙げられる。また、円、楕円、正多角形等のように図形自体が回転対称性を有していても、シャフト１４０が中心からずれた位置を貫通していれば、３６０°以外の回転に対して非対称な形状に相当する。 Examples of asymmetric shapes with respect to rotations other than 360 ° with the shaft 140 as the rotation center include trapezoids, odd-numbered squares such as triangles, pentagons, and heptagons (excluding regular polygons). Even if the figure itself has rotational symmetry such as a circle, ellipse, regular polygon, etc., as long as the shaft 140 passes through a position deviated from the center, it is asymmetric with respect to rotations other than 360 °. It corresponds to a simple shape.
　１１…円筒部、１２…フランジ部、１３…フランジ部、１４…ボス部、１５…穴、１００…リニアアクチュエータ、１１０…ステータ構造体、１１１…コイル、１１２…コイル、１１３…ボビン、１１４…ボビン、１１５…ステータヨーク、１１５ａ…端面、１１５ｂ…ステータヨーク１１５の歯、１１６…ステータヨーク、１１７…ステータヨーク、１１７ｂ…ステータヨーク１１７の歯、１１８…ステータヨーク、１１９…充填された樹脂、１２０…フロントプレート、１２１…孔、１２２…固定用腕部、１２３…孔、１２５…端子ピン、１３０…ロータ、１３１…内側円筒部材、１３２…ロータマグネット、１３３…雌ねじ、１３４…玉軸受、１３５…玉軸受、１３５a…軸受収容空間、１４０…シャフト、１４１…雄ねじ構造、１４２…先端部、１４３…回り止め部材、１４３ｂ…端面、１４４…ピン、１５０…フロントハウジング、１５１…突起、１５２…ボス部、１５３…柱状空間、１５４…内側ハウジング部、１５４ａ…接触面、１５５…溝、１５６…円筒部、１６１…上側曲面、１６２…下側曲面、１６３…側面、１６４…側面、１７１…上側曲面、１７２…下側曲面、１７３…側面、１７４…側面、１７０…エンドハウジング。 DESCRIPTION OF SYMBOLS 11 ... Cylindrical part, 12 ... Flange part, 13 ... Flange part, 14 ... Boss part, 15 ... Hole, 100 ... Linear actuator, 110 ... Stator structure, 111 ... Coil, 112 ... Coil, 113 ... Bobbin, 114 ... Bobbin 115 ... Stator yoke, 115a ... End face, 115b ... Stator yoke 115 teeth, 116 ... Stator yoke, 117 ... Stator yoke, 117b ... Stator yoke 117 teeth, 118 ... Stator yoke, 119 ... Filled resin, 120 ... Front plate, 121 ... hole, 122 ... fixing arm, 123 ... hole, 125 ... terminal pin, 130 ... rotor, 131 ... inner cylindrical member, 132 ... rotor magnet, 133 ... female screw, 134 ... ball bearing, 135 ... ball Bearing, 135a ... Bearing housing space, 140 ... Shaft, 141 ... Male thread structure, 14 2 ... tip part, 143 ... anti-rotation member, 143b ... end face, 144 ... pin, 150 ... front housing, 151 ... projection, 152 ... boss part, 153 ... columnar space, 154 ... inner housing part, 154a ... contact surface, 155 ... groove, 156 ... cylindrical part, 161 ... upper curved surface, 162 ... lower curved surface, 163 ... side surface, 164 ... side surface, 171 ... upper curved surface, 172 ... lower curved surface, 173 ... side surface, 174 ... side surface, 170 ... end housing .

Claims (5)

  1. 　ハウジングと、
    　前記ハウジングに回転可能な状態で保持されたロータと、
    　前記ロータの回転に伴って前記ロータの回転方向とは異なる軸方向に移動可能な出力軸と、
    　前記ハウジングに設けられた前記軸方向に延在する空間に配置され、前記軸方向と交差する第１の面を有する回り止め部材であって、前記空間の内部を前記軸方向に摺動可能であり、前記出力軸に固定された前記回り止め部材と
    　を備え、
    　前記ハウジングには、前記回り止め部材の前記第１の面が接触可能な第２の面が設けられたリニアアクチュエータ。     A housing;
    A rotor held rotatably in the housing;
    An output shaft movable in an axial direction different from the rotation direction of the rotor in accordance with the rotation of the rotor;
    A detent member disposed in a space provided in the housing and extending in the axial direction and having a first surface intersecting the axial direction, and is slidable in the axial direction inside the space. And the anti-rotation member fixed to the output shaft,
    The linear actuator, wherein the housing is provided with a second surface that can contact the first surface of the detent member.
  2. 　前記回り止め部材は、筒形状を有し、
    　前記筒形状の外周面が前記空間の内周面に摺動可能な状態とされ、
    　前記軸方向から見た前記回り止め部材の形状は、前記出力軸を回転中心とした３６０°以外の回転に対して非対称な形状を有する請求項１に記載のリニアアクチュエータ。     The detent member has a cylindrical shape,
    The cylindrical outer peripheral surface is slidable on the inner peripheral surface of the space,
    2. The linear actuator according to claim 1, wherein the shape of the anti-rotation member viewed from the axial direction is asymmetric with respect to rotation other than 360 ° with the output shaft as a rotation center.
  3. 　前記回り止め部材の外周面は、
    　第１の曲率を有する第１の曲面と、
    　第２の曲率を有する第２の曲面と、
    　前記第１の曲面と前記第２の曲面とを直接、あるいは段差を介してつなぐ２つの平面とにより構成されている請求項２に記載のリニアアクチュエータ。     The outer peripheral surface of the anti-rotation member is
    A first curved surface having a first curvature;
    A second curved surface having a second curvature;
    The linear actuator according to claim 2, wherein the linear actuator is configured by two planes that connect the first curved surface and the second curved surface directly or via a step.
  4. 　前記回り止め部材は、樹脂により構成され、
    　前記出力軸には、前記軸方向に交差する方向に貫通した孔が設けられ、
    　前記回り止め部材を構成する前記樹脂が前記孔の内部に充填された状態で、前記回り止め部材が前記出力軸に固定され、
    　前記孔の向きと前記非対称な形状とに特定の関係がある請求項２または３に記載のリニアアクチュエータ。     The anti-rotation member is made of resin,
    The output shaft is provided with a hole penetrating in a direction intersecting the axial direction,
    In the state where the resin constituting the anti-rotation member is filled in the hole, the anti-rotation member is fixed to the output shaft,
    The linear actuator according to claim 2 or 3, wherein there is a specific relationship between a direction of the hole and the asymmetric shape.
  5. 　前記ロータは第１のねじ構造を備え、
    　前記出力軸は前記第１のねじ構造と噛み合った第２のねじ構造を備え、
    　前記出力軸における前記回り止め部材の位置と、
    　前記第１のねじ構造と前記第２のねじ構造における歯の噛合い位置との関係が特定の関係に設定されている請求項１乃至４のいずれか一項に記載のリニアアクチュエータ。     The rotor comprises a first threaded structure;
    The output shaft includes a second screw structure engaged with the first screw structure;
    The position of the detent member on the output shaft;
    5. The linear actuator according to claim 1, wherein a relationship between tooth engagement positions of the first screw structure and the second screw structure is set to a specific relationship.
PCT/JP2018/010929 2017-03-21 2018-03-20 Linear actuator WO2018174039A1 (en)

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JP2002122203A (en) * 2000-10-17 2002-04-26 Minebea Co Ltd Linear actuator
US6603229B1 (en) * 2000-11-15 2003-08-05 Tri-Tech, Inc. Linear actuator with threaded captivation sleeve, captive lead screw, and spring pre-load adjustment
JP5263652B2 (en) * 2007-05-17 2013-08-14 日本精工株式会社 Actuator
JP5785016B2 (en) 2011-07-25 2015-09-24 ミネベア株式会社 Linear actuator
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JPH10322963A (en) * 1997-03-18 1998-12-04 Asmo Co Ltd Actuator
JPH11155275A (en) * 1997-11-25 1999-06-08 Asmo Co Ltd Steeping motor, optical axis adjustment device and transfer range setting method
US7408277B2 (en) * 2006-10-20 2008-08-05 Hsian-Yi Huang Step-by-step motor able to carry out up-and-down motion

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