JP5755890B2 - Linear motor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a linear motor in which a magnet shaft inserted in a coil array moves linearly relative to a coil, and a method for manufacturing the linear motor.

  As this type of linear motor, a cylindrical linear motor is known in which a plurality of coils are laminated in the axial direction and a rod is inserted into the laminated coil array. N poles and S poles are alternately formed on the rod in the axial direction. The coil array is formed by laminating a plurality of three coil units in the axial direction. When a three-phase alternating current having a phase difference of 120 degrees of U phase, V phase, and W phase is passed through the three coils of the coil unit, a moving magnetic field is generated in the coil array. The rod obtains thrust by the moving magnetic field of the coil array, and linearly moves in the axial direction (see Patent Document 1).

  The coil array is generally housed in a cylindrical housing. In stacking the coil rows, a shaft is passed through the inner circumference side of the coil rows. After the coil row that has passed through the shaft is accommodated in the housing, the housing is filled with a fluid adhesive. The coil array is fixed to the housing by an adhesive. After fixing the coil array to the housing, the shaft on the inner peripheral side of the coil array is extracted from the coil array.

  As another method of housing the coil array in the housing, after holding the coil array with the coil holder, the coil array is inserted into the mold together with the coil holder, and the housing is filled by filling the mold with fluid resin. A manufacturing technique has also been proposed (see Patent Document 2). The coil array is integrated with the housing at the same time that the housing is injection molded.

US Patent Application Publication No. 2004/0075518 JP 2009-247068 (see paragraphs 0027-0029)

  However, the linear motor described in Patent Document 1 has a problem that the outer diameter of the housing is larger than the outer diameter of the coil array because the coil array is surrounded by the cylindrical housing. For example, when a plurality of linear motors are arranged with the axis of the magnet shaft in parallel, it is required to suppress the width dimension of the linear motor as much as possible.

  In the linear motor described in Patent Document 2, since the housing is formed by injection molding, there is an advantage that the width dimension of the linear motor can be suppressed. However, it requires a mold for injection molding. There are cases where it is difficult to manufacture a mold from the viewpoint of cost, such as when manufacturing a small amount of other types of linear motors.

  Then, an object of this invention is to provide the assembly-type linear motor which can suppress the width dimension of a linear motor, and its manufacturing method.

In order to solve the above problems, according to one aspect of the present invention, a magnet shaft in which N poles and S poles are alternately formed in the axial direction, and an axial direction of the magnet shaft are arranged so as to surround the magnet shaft A coil array including a plurality of coils, and a housing in which the coil array is accommodated, and a magnet shaft is relatively axially relative to the housing and the coil array by passing a current through the coil array. In the linear motor that moves linearly, the housing extends in the axial direction of the coil row and is sandwiched between the first member and the second member, and the axial ends of the first member and the second member. and a pair of end members that the magnet shaft penetrates while being coupled, the first member is formed in a U-shaped section, and a bottom wall, or the bottom wall A pair of side wall portions projecting toward the second member and facing each other, and the second member is formed in a U-shaped cross section, and has a bottom wall portion and a first wall portion extending from the bottom wall portion. A linear motor that protrudes toward one member and has a pair of side wall portions facing each other, and at least a part of the periphery of the coil array is not surrounded by the first member and the second member.

Another aspect of the present invention is a coil array including a magnet shaft in which N poles and S poles are alternately formed in the axial direction, and a plurality of coils arranged in the axial direction of the magnet shaft so as to surround the magnet shaft. And a housing in which the coil array is housed, and a magnet shaft moves linearly relative to the housing and the coil array in a linear direction relative to the housing and the coil array by passing a current through the coil array. In the method, the step of sandwiching the coil array so as not to surround at least a part of the periphery of the coil array by the first member and the second member extending in the axial direction of the coil array; and the first member and the second member comprising the step of the magnet shaft at both ends in the axial direction of the member couples the pair of end members which penetrate, the said first member is formed in a U-shaped section, the bottom And a pair of side wall portions projecting from the bottom wall portion toward the second member and facing each other, and the second member is formed in a U-shaped cross section, and the bottom wall portion protrudes toward from the bottom wall portion to the first member, a manufacturing method of a linear motor that having a, a pair of side wall portions facing each other.

  According to the present invention, since the width dimension of the first member and the second member of the housing can be suppressed to a dimension close to the outer diameter of the coil, the width dimension of the linear motor can be suppressed.

A perspective view of a linear motor in one embodiment of the present invention (a figure (a) shows a state where a magnet axis was pulled in, and a figure (b) shows a state where a magnet axis was pulled out) Exploded perspective view of housing Sectional view along the axis of the magnet shaft of the linear motor Perspective view of coil array and wiring board Detailed view of housing (FIG. (A) shows a plan view, FIG. (B) shows a side view, and FIG. (C) shows a sectional view) Fig. 5 Detailed view of VI section Sectional drawing which shows the state which pinched | interposed the coil row | line | column with the 1st member and 2nd member of a housing Comparison diagram of width dimension of conventional linear motor and linear motor of this embodiment (FIG. (A) shows a conventional linear motor and FIG. (B) shows a linear motor of this embodiment)

  Hereinafter, a linear motor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a linear motor. FIG. 1A shows a state in which the magnet shaft 1 is pulled into the housing 2, and FIG. 1B shows a state in which the magnet shaft 1 is pulled out from the housing 2.

  For example, this linear motor is incorporated in a mounter that places electronic components attracted by the tip of the magnet shaft 1 on a printed circuit board. The linear motor may be used alone, or may be used as a unit arranged in the width direction. When used as a unit, a plurality of linear motors are arranged so that the axis of the magnet shaft 1 is parallel. In order to make the width dimension of the unit as small as possible, the width dimension of each linear motor is minimized. If a plurality of linear motors can be incorporated into the mounter as a unit, the processing speed can be improved in proportion to the number of magnet shafts 1.

  As shown in FIG. 1, the linear motor is equipped with a rotation preventing mechanism for the magnet shaft 1. Although the linear motor can also be constituted by the housing 2 and the magnet shaft 1, an anti-rotation mechanism is additionally provided. The anti-rotation mechanism linearly moves together with the magnet shaft 1, the guide shaft 6 parallel to the magnet shaft 1, the connecting shaft 7 attached to the guide shaft 6 and the tip of the magnet shaft 1, and the connecting member 7 moves linearly. A bush (the bush is accommodated in the bush accommodating portion 8). A bracket 9 is attached to one end of the housing 2, and a bush housing 8 is attached to the bracket 9. A bush for guiding the guide shaft 6 is stored in the bush storage portion 8. The tip of the guide shaft 6 and the tip of the magnet shaft 1 are connected by a connecting member 7. The magnet shaft 1 is non-rotatably coupled to the connecting member 7. A linear encoder 11 for detecting the position of the magnet shaft 1 is attached to the other end of the guide shaft 6. A read head (not shown) that cooperates with the linear encoder 11 is attached to the housing 2.

  FIG. 2 shows an exploded perspective view of the housing 2 of the linear motor. An elongated rectangular parallelepiped housing 2 accommodates a coil array 3 surrounding the magnet shaft 1. Three coil arrays 3 are a set of coil units 3a to 3c stacked in the axial direction. The coil units 3a to 3c include a U-phase coil 3a, a V-phase coil 3b, and a W-phase coil 3c. The coil array 3 is formed by laminating a number of coils 3a to 3c and spacers 12 alternately in the axial direction. Adjustment spacers 13 for adjusting the axial length of the coil array 3 are provided at both ends of the coil array 3 in the axial direction. The thickness of the adjustment spacer 13 at the end of the coil array 3 in the axial direction is thicker than the thickness of the spacer 12 between the coils. The adjustment spacer 13 adjusts the length of the coil array 3 so that the length of the coil array 3 in the axial direction is equal to the distance between the pair of end members 23 and 24.

  A three-phase alternating current having a phase difference of 120 degrees flows through the U-phase coil 3a, the V-phase coil 3b, and the W-phase coil 3c. The magnet shaft 1 obtains a thrust by a moving magnetic field generated in the coil array 3 and performs a linear motion relative to the coil array 3 in the axial direction.

  The coil array 3 is surrounded by the housing 2. The housing 2 is elongated in the axial direction of the coil array 3 and is coupled to the first member 21 and the second member 22 sandwiching the coil array 3 in the vertical direction, and a pair coupled in the axial direction of the first member 21 and the second member 22. End members 23, 24 and a pair of plate members 26, 27 that connect both side surfaces of the pair of upper and lower first members 21 and second member 22. The first member 21, the second member 22, the pair of end members 23 and 24, and the pair of plate members 26 and 27 form an outer shape of the linear motor.

  The first member 21 is formed in a U-shaped cross section, and protrudes from the bottom wall portion 21a (upper side in FIG. 2) and the bottom wall portion 21a toward the second member 22 (downward) and is opposed to each other. A side wall 21b is provided. The second member 22 is also formed in a U-shaped cross section, and includes a bottom wall portion 22a and a pair of side wall portions 22b that protrude (upward) from the bottom wall portion 22a toward the first member 21 and face each other. When the coil row 3 is sandwiched between the first member 21 and the second member 22, the side wall portion 21b of the first member 21 and the side wall portion 22b of the second member 22 abut against the coil row 3 (see FIG. 7). The cross sections at the tips of the side wall portion 21 b of the first member 21 and the side wall portion 22 b of the second member 22 are formed in an arc shape that matches the outer diameter of the coil array 3. When the coil group 3 is sandwiched between the first member 21 and the second member 22, the axial direction of the coil group 3 is between the coil group 3 and the first member 21 and between the coil group 3 and the second member 22. Clearances g1 and g2 (see FIG. 7) extending to A substrate 29 (see FIG. 4) that is electrically connected to the coil array 3 is inserted into the gaps g1 and g2.

  As shown in FIG. 2, flanges 21 c for connecting the end members 23 and 24 to the first member 21 are formed at both ends in the length direction of the first member 21. One flange 21 c is formed with a notch 30 for drawing out the lead wire of the substrate 29 to the outside of the housing 2. Flange 22c for connecting end members 23 and 24 is also formed at both ends in the length direction of second member 22.

  The flanges 21c and 22c are formed with screw holes 31 for attaching end members. The flanges 21 c and 22 c are formed with positioning holes 32 for positioning the end members 23 and 24 with respect to the first member 21 and the second member 22. Screw holes 33 for attaching the plate members 26 and 27 are formed on the side surfaces of the side wall portions 21 b and 22 b of the first member 21 and the second member 22. Further, the first member 21 is formed with a positioning pin insertion hole 36 as an attachment portion for attaching the linear motor to a counterpart part such as a mounter. The first member 21 may be formed with a screw hole, a mounting hole or the like in addition to the positioning pin insertion hole 36 as a mounting portion. The second member 22 is formed with a screw hole 39 (see FIG. 5) for attaching the read head.

  End members 23 and 24 are coupled to the longitudinal ends of the first member 21 and the second member 22 via fastening members such as screws 43. The end members 23 and 24 are formed in a rectangular parallelepiped shape elongated in the vertical direction. The end members 23 and 24 are formed with holes 41 through which the magnet shaft 1 passes. A bush (not shown) for guiding the magnet shaft 1 is inserted into the hole 41. The bush is pressed into the end members 23 and 24 by a bracket 9 (see FIG. 1) attached to the end members 23 and 24. As shown in FIG. 2, the end members 23 and 24 are formed with through holes 44 through which screws 43 as fastening members are passed. The end members 23 and 24 are formed with positioning holes 45 corresponding to the positioning holes 32 provided in the first member 21 and the second member 22. The end members 23 and 24 are positioned on the first member 21 and the second member 22 through pins through the positioning hole 32 and the positioning hole 45, and then the screw 43 is screwed into the first member 21 and the second member 22. 23 and 24 are coupled to the first member 21 and the second member 22. The end members 23 and 24 are formed with screw holes 47 for mounting the bracket 9 (see FIG. 1).

  Since the coil array 3 is sandwiched between the first member 21 and the second member 22 in the vertical direction, the coil array 3 is positioned in the radial direction. Further, since the coil array 3 is sandwiched between the pair of end members 23 and 24 in the axial direction, the coil array 3 is positioned in the axial direction.

  By positioning the end members 23 and 24 with respect to the first member 21 and the second member 22, the end members 23 and 24 are supported with respect to the coil array 3 sandwiched between the first member 21 and the second member 22. The magnet shaft 1 can be positioned so that these center lines coincide.

  The plate members 26 and 27 are formed in an elongated plate shape in the axial direction of the coil array 3. The plate members 26 and 27 are made of a magnetic material such as iron that is magnetized when placed in a magnetic field. The plate members 26 and 27 are formed with through holes 52 through which screws 51 as fastening members pass. The plate members 26 and 27 are attached to the first member 21 and the second member 22 by screws. The plate members 26 and 27 are parallel to each other.

  FIG. 3 shows a cross-sectional view along the axial direction of the magnet shaft 1. The magnet shaft 1 includes a hollow pipe 61, a number of magnets 62 inserted into the pipe 61, and a plurality of magnetic pole blocks 63 interposed between the magnets 62. The plurality of magnets 62 are magnetized in the axial direction, and an N pole and an S pole are formed at the ends in the axial direction. The plurality of magnets 62 are arranged so that the N poles and the S poles face each other. The magnetic pole block 63 is made of a magnetic material such as iron. The magnetic pole block 63 brings the magnetic field generated in the magnet shaft 1 closer to a sine wave.

  The structure of the magnet shaft 1 is not limited to that described above as long as the N pole and the S pole are alternately formed in the axial direction. For example, a magnet magnetized in the radial direction may be used, the magnetic pole block 63 may not be provided between the magnets 62, or a ring-shaped magnet may be disposed outside the pipe 61. Good.

  The method for assembling the linear motor housing 2 is as follows. As shown in FIG. 4, the coil array 3 is configured by alternately stacking coils 3 a, spacers 12, coils 3 b, spacers 12... In the axial direction. While the coils 3a to 3c and the spacer 12 are laminated, they are passed through the shaft 66 (see FIG. 5). The inner diameter of the coil array 3 is equal to the outer diameter of this shaft. After passing the coil array 3 through the shaft, the lead wires 64 of the coils 3 a to 3 c are passed through the through holes 29 a of the substrate 29. Electrode patterns are formed on the substrate 29 so as to connect the U-phase coils 3a, the V-phase coils 3b, and the W-phase coils 3c.

  FIG. 7 shows a state in which the coil array 3 passed through the shaft 66 is surrounded by the housing 2. The coil array 3 is sandwiched between the first member 21 and the second member 22 in the vertical direction (radial direction of the coil array 3). By connecting the end members 23 and 24 to the end portions of the first member 21 and the second member 22 in the axial direction, the state in which the first member 21 and the second member 22 sandwich the coil array 3 in the vertical direction can be maintained. It becomes like this. Since the shaft 66 is passed through the end members 23 and 24, the coaxiality of the coil array 3 and the magnet shaft 1 is ensured. As shown in FIG. 6, when the end members 23 and 24 are coupled to the first member 21 and the second member 22, the end members 23 and 24 come into contact with the adjustment spacer 13 provided at the end of the coil array 3 in the axial direction. The coil array 3 is sandwiched between the pair of end members 23 and 24 in the axial direction.

  As shown in FIG. 7, the width dimension W1 of the first member 21 and the second member 22 is equal to each other, and these width dimensions W1 are substantially equal to the diameter φD of the coil array 3 or less than φD. In order to insulate the coils 3a to 3c, the periphery of the coil array 3 is wound with an insulating tape or covered with an adhesive or resin film (an example of covering the coil array 3 with an adhesive or resin film will be described later) To do). The width dimension W1 of the first member 21 and the second member 22 and the diameter φD of the coil array 3 are substantially equal. The width dimension W1 is equal to the outer diameter of the coil array 3 and the thickness of the insulating tape, adhesive, or resin. It means equal to the dimension plus the thickness of the film.

  An example in which an adhesive or a resin as a filler is filled in the housing 2 will be described with reference to FIG. When the end members 23, 24 are coupled to the first member 21 and the second member 22, the coil row 3 is surrounded by the frame-shaped housing 2 as viewed from the side of the coil row 3 as shown in FIG. First, a portion of the coil array 3 exposed from the housing 2 is covered with a plate-like cover member (not shown). The cover member is coupled to the side surfaces of the pair of upper and lower first members 21 and second member 22. Next, the housing 2 is filled with a fluid adhesive or resin (thermosetting resin). The adhesive or resin is filled into the housing 2 through the filling hole 68 of the first member 21.

  As shown in FIG. 5B, at the lower end portion of the side wall portion 21 b of the first member 21, protruding portions 71 and non-projecting portions 72 having different vertical heights are alternately formed in the axial direction. Also at the upper end portion of the side wall portion 22b of the second member 22, protruding portions 73 and non-projecting portions 74 having different vertical heights are alternately formed in the axial direction. The pitch P1 of the protrusion 71 of the first member 21 is different from the pitch of the protrusion 73 of the second member 22 in the axial direction. It is easy to flow into.

  The adhesive or resin filled in the housing 2 fills the gap between the coil row 3 and the first member 21 and the gap between the coil row 3 and the second member 22. Then, the exposed portions P1 and P2 (see FIG. 7) of the coil array 3 are covered. As a result, the coil array 3 is firmly bonded to the housing 2, and the exposed portions P1 and P2 of the coil array 3 are covered with an adhesive or resin film that is an insulating material. After filling the housing 2 with adhesive or resin, the cover member is removed from the housing 2. Thereafter, the shaft 66 is removed from the coil array 3.

  As shown in FIG. 7, when the coil group 3 is sandwiched between the first member 21 and the second member 22, at least part of the periphery of the coil group 3, in this embodiment, two left and right locations P <b> 1 of the coil group 3. P <b> 2 is not surrounded by the first member 21 and the second member 22. Even when covered with an adhesive or resin film, the coil array is not surrounded by the first member 21 and the second member 22. That is, the left and right two places P 1 and P 2 of the coil array 3 are exposed from the first member 21 and the second member 22. The exposed portion of the coil array 3 is covered with a magnetic plate member 26 (see FIG. 2). The plate member 26 shields the magnetic field of the magnet shaft 1 and links the magnetic field of the magnet shaft 1 to the coils 3a to 3c to improve thrust (that is, as a back yoke constituting a magnetic circuit of the linear motor). It is provided in order to demonstrate the function.

  FIG. 8 is a diagram comparing width dimensions of a conventional linear motor in which the coil array 3 is insert-molded and the assembly type linear motor of the present embodiment. In the figure, (a) shows a conventional linear motor, and (b) in the figure shows the linear motor of this embodiment. In the conventional linear motor, the width W2 in the left-right direction of the housing 2 is reduced by insert molding the coil array 3. However, since the left and right sides in the width direction of the coil array 3 are also covered with the resin of the housing 2, the width dimension W <b> 2 is obtained by adding the resin thickness to the outer diameter of the coil array 3.

  On the other hand, in this embodiment, the coil row 3 is sandwiched in the vertical direction by the first member 21 and the second member 22 that are divided vertically, and the left and right sides of the coil row 3 are the first member 21 and the second member. 22 is exposed. For this reason, even if the plate member 26 is attached to the housing 2, the width dimension in the left-right direction is W3 smaller than the width dimension W2 of the conventional linear motor, and the width dimension W3 in the left-right direction of the linear motor is It can be suppressed to near the outer diameter. Moreover, since it is an assembly-type linear motor that does not use a mold for insert molding, it is suitable for manufacturing a wide variety of small-sized linear motors having various lengths.

  In addition, this invention is not limited to the said embodiment, In the range which does not change the summary of this invention, it can change variously. For example, the housing may be constituted by a first member, a second member, and a pair of end members, and the specific shape thereof can be variously changed.

  The end member only needs to have a hole through which the magnet shaft passes, and the end member may not be provided with a bush for guiding the magnet shaft.

  The first member, the second member, and the end member may be coupled by other coupling means such as adhesion and welding in addition to screw coupling.

  If the magnetic field generated in the magnet shaft does not affect the surroundings, the plate member can be eliminated. When the plate member is attached to the housing, the housing need not be filled with an adhesive or resin.

  The linear motion of the magnet shaft relative to the coil row is relative, and the coil row may move linearly relative to the magnet shaft.

  There may be no clearance between the first part and the coil array and / or the clearance between the second member and the coil array. Since the substrate does not enter, there may be no gap between the second member and the coil array. If this clearance is eliminated, the dimension of the linear motor in the vertical direction (vertical direction) can be reduced.

  The total number of coils may be three. In the case of a two-phase motor, two may be used. In the case of a two-phase motor, a linear motor may be used as a vibration actuator.

DESCRIPTION OF SYMBOLS 1 ... Magnet shaft, 2 ... Housing, 3 ... Coil row | line | column, 3a-3c ... Coil, 21 ... 1st member, 22 ... 2nd member, 23, 24 ... End member, 26, 27 ... Plate member

Claims (7)

A magnet shaft in which N poles and S poles are alternately formed in the axial direction, a coil array including a plurality of coils arranged in the axial direction of the magnet shaft so as to surround the magnet shaft, and the coil array are accommodated A linear motor in which a magnet shaft linearly moves in an axial direction relative to the housing and the coil array by passing an electric current through the coil array.
The housing is
A first member and a second member extending in the axial direction of the coil row and sandwiching the coil row;
A pair of end members coupled to both axial ends of the first member and the second member and through which the magnet shaft passes,
The first member is formed in a U-shaped cross section, and has a bottom wall portion and a pair of side wall portions that protrude from the bottom wall portion toward the second member and face each other.
The second member is formed in a U-shaped cross section, and has a bottom wall portion and a pair of side wall portions that protrude from the bottom wall portion toward the first member and face each other.
A linear motor in which at least a part of the periphery of the coil array is not surrounded by the first member and the second member.   The linear motor according to claim 1, wherein the pair of end members sandwich the coil array in the axial direction. The first member and the second member are connected by a magnetic plate member,
The linear motor according to claim 1, wherein the plate member covers at least a part of the periphery of the coil array that is not surrounded by the first member and the second member. Filled with a filler for fixing the coil array in the housing,
The linear motor according to claim 1, wherein the filler covers at least a part of the periphery of the coil that is not surrounded by the first member and the second member.   When the first member and the second member are arranged so as to sandwich the coil row in the vertical direction when viewed from the axial direction, the width dimension in the left-right direction of the first member and the second member is the coil row. 5. The linear motor according to claim 1, wherein the linear motor is substantially equal to or less than an outer diameter of the coil array. A magnet shaft in which N poles and S poles are alternately formed in the axial direction, a coil array including a plurality of coils arranged in the axial direction of the magnet shaft so as to surround the magnet shaft, and the coil array are accommodated A linear motor that moves linearly relative to the housing and the coil array by causing a current to flow through the coil array.
Sandwiching the coil array so as not to surround at least a part of the periphery of the coil array by a first member and a second member extending in the axial direction of the coil array;
Coupling a pair of end members through which the magnet shaft passes to both ends in the axial direction of the first member and the second member , and
The first member is formed in a U-shaped cross section, and has a bottom wall portion and a pair of side wall portions that protrude from the bottom wall portion toward the second member and face each other.
Said second member is a linear motor that Yusuke is formed in a U-shaped section, and a bottom wall portion protrudes toward from the bottom wall portion to the first member, a pair of side wall portions facing each other, the Manufacturing method. Covering at least a part of the periphery of the coil array not surrounded by the first member and the second member with a cover member;
Filling a fluid filler in a space surrounded by the first member, the second member, the pair of end members and the cover member;
The method for manufacturing a linear motor according to claim 6, further comprising: removing the cover member from the first member, the second member, and the pair of end members.

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