JP2021016219A - Stepping motor - Google Patents

Abstract

To provide a stepping motor capable of suppressing the distortion of a rotary shaft between magnets even in the case where a permanent magnet of a rotor is constituted of a plurality of magnets.SOLUTION: In a stator part 3 of a stepping motor 1, each of a plurality of stators 30 which are disposed while being overlapped in a motor axis direction L includes an A-phase stator group 30A and a B-phase stator group 30B. Therefore, four or more stator groups are provided in the stator part 3. In a rotor 2, a permanent magnet 22 is constituted of a plurality of magnets 220 disposed in the motor axis direction L, and a connection part 25 connecting magnets 220 which are adjacent in the motor axis direction L, with each other is provided in the rotor 2. Therefore, a rotary shaft 21 is hard to bend. The connection part 25 is, for example, a spacer 26 which is adhered to the magnets 220. An outer diameter of the stator 30 is equal to or smaller than 6 mm, and an outer diameter of the rotary shaft 21 is equal to or smaller than 1 mm.SELECTED DRAWING: Figure 3

Description

The present invention relates to a stepping motor in which four or more sets of stators are arranged in the direction of the motor axis.

The stepping motor includes a rotor having a permanent magnet fixed to the outer peripheral surface of the rotating shaft, and a stator arranged so as to face the outer peripheral surface of the permanent magnet. On the other hand, as a structure capable of securing a large torque even when the diameter of the stepping motor is reduced, a structure in which a plurality of four or more stator sets are arranged in the motor axis direction has been proposed (see Patent Document 1). FIG. 1 of Patent Document 1 describes an embodiment in which a permanent magnet is composed of a plurality of magnets in a rotor, and FIG. 2 of Patent Document 1 describes an embodiment in which a permanent magnet is composed of one magnet in a rotor. Has been done.

Japanese Unexamined Patent Publication No. 2000-152593

When a plurality of four or more stator sets are arranged in the motor axial direction, the dimensions of the stator in the axial direction become long. Therefore, when the permanent magnet is composed of one magnet as shown in FIG. 2 of Patent Document 1, the permanent magnet becomes long and it is not easy to manufacture the permanent magnet. On the other hand, when the permanent magnet is composed of a plurality of magnets as shown in FIG. 1 of Patent Document 1, the magnets can be easily manufactured, but due to the magnetic force acting between the stator portion and the permanent magnets. There is a problem that the rotating shaft easily bends between magnets when the rotor rotates or when an impact load is applied.

In view of the above problems, an object of the present invention is to provide a stepping motor capable of suppressing bending of a rotating shaft between magnets even when the permanent magnet of the rotor is composed of a plurality of magnets. There is.

In order to solve the above problems, one aspect of the stepping motor according to the present invention is to have a rotor provided with a permanent magnet on the outer peripheral side of a rotating shaft extending in the motor axis direction and a rotor facing the permanent magnet radially outward. It has a cylindrical stator portion that is arranged, and in the stator portion, a stator set in which a first core, a coil bobbin around which a coil is wound, and a second core are stacked in the motor axis direction is formed in the motor axis direction. Four or more sets are arranged, and the permanent magnets are composed of a plurality of magnets arranged in the motor axis direction, and among the plurality of magnets, adjacent magnets in the motor axis direction are connected to the rotor. It is characterized in that a connecting portion is provided.

In the present invention, since four or more sets of stators are arranged in the direction of the motor axis, a large torque can be obtained even when the diameter of the motor is reduced, and the permanent magnet is in the direction of the motor axis. Since it is composed of a plurality of magnets arranged in, the magnets can be easily manufactured. Further, since the rotor is provided with a connecting portion for connecting magnets adjacent to each other in the direction of the motor axis, when the rotor is rotated by the magnetic force acting between the stator portion and the permanent magnet, or an impact load is applied. It is possible to prevent the rotation shaft from bending between the magnets when the magnets are applied.

In the present invention, the connecting portion may adopt a mode in which the connecting portion is a spacer adhered to the magnets between the magnets adjacent to each other in the motor axis direction among the plurality of magnets. According to this aspect, the magnets can be connected to each other via the spacer even when the distance between the magnets is wide.

In the present invention, the connecting portion can adopt an aspect in which the connecting portion is an adhesive layer that connects magnets adjacent to each other in the motor axis direction among the plurality of magnets. According to this aspect, the magnets can be connected to each other without using a spacer or the like.

Another aspect of the motor according to the present invention is a rotor having a permanent magnet on the outer peripheral side of a rotating shaft extending in the direction of the motor axis, and a tubular stator arranged so as to face the permanent magnet outward in the radial direction. In the stator portion, four or more sets of a first core, a coil bobbin around which a coil is wound, and a stator set in which a second core is overlapped in the motor axis direction are arranged in the motor axis direction. The permanent magnet is composed of a plurality of magnets arranged in the direction of the motor axis, and extends in the direction of the motor axis between the plurality of magnets adjacent to each other in the direction of the motor axis. It is characterized in that a tubular member is attached.

In the present invention, since four or more sets of stators are arranged in the direction of the motor axis, a large torque can be obtained even when the diameter of the motor is reduced, and the permanent magnet is in the direction of the motor axis. Since it is composed of a plurality of magnets arranged in, the magnets can be easily manufactured. Further, since a tubular member is mounted on the rotating shaft between magnets adjacent to each other in the direction of the motor axis, when the rotor rotates due to the magnetic force acting between the stator and the permanent magnet, or an impact load is applied. It is possible to prevent the rotation shaft from bending between the magnets when the force is applied.

Yet another aspect of the motor according to the present invention is a rotor having a permanent magnet on the outer peripheral side of a rotating shaft extending in the direction of the motor axis, and a tubular shape arranged so as to face the permanent magnet radially outward. It has a stator portion, and in the stator portion, four or more sets of a first core, a coil bobbin around which a coil is wound, and a stator set in which a second core is overlapped in the motor axis direction are arranged in the motor axis direction. The permanent magnet is composed of a plurality of magnets arranged in the direction of the motor axis, and the rotation axis is coated with a coating layer between the magnets adjacent to each other in the direction of the motor axis among the plurality of magnets. It is characterized by that.

In the present invention, since four or more sets of stators are arranged in the direction of the motor axis, a large torque can be obtained even when the diameter of the motor is reduced, and the permanent magnet is in the direction of the motor axis. Since it is composed of a plurality of magnets arranged in, the magnets can be easily manufactured. In addition, since the magnets of the rotating shaft are coated with a coating layer, the magnets and magnets are rotated when the rotor is rotated by the magnetic force acting between the stator and the permanent magnets, or when an impact load is applied. It is possible to prevent the rotating shaft from bending between and.

In the present invention, the stator portion adopts an embodiment in which, among the plurality of stator sets, a plurality of stators composed of two stator sets adjacent to each other in the motor axis direction are arranged in the motor axis direction. Can be done.

In the present invention, in the plurality of stator portions, one of the two stator sets is an A-phase stator set, and the other is a B-phase stator set.

In the present invention, in each of the plurality of stator sets, the first core includes a tubular case portion that bends at the outer peripheral edge of an annular plate portion that overlaps the coil bobbin to cover the coil from the radial outside. Aspects can be adopted.

In the present invention, an embodiment in which the outer diameter of the plurality of stators is 6 mm or less and the outer diameter of the rotating shaft is 1 mm or less can be adopted.

In the present invention, the stator portion can adopt an embodiment having four stator sets as the plurality of stator sets.

In the present invention, since four or more sets of stators are arranged in the direction of the motor axis, a large torque can be obtained even when the diameter of the motor is reduced, and the permanent magnet is in the direction of the motor axis. Since it is composed of a plurality of magnets arranged in, the magnets can be easily manufactured. Further, since a connecting portion for connecting the magnets, a tubular member mounted on the rotating shaft, and a coating layer coated on the rotating shaft are provided between adjacent magnets, the stator portion and the permanent magnet are provided. It is possible to prevent the rotation shaft from bending between the magnets when the rotor is rotated by the magnetic force acting between the magnets or when an impact load is applied.

The perspective view of the stepping motor which concerns on this invention. A perspective view of the stepping motor shown in FIG. 1 when viewed from another direction. FIG. 3 is a cross-sectional view of the stepping motor shown in FIG. An exploded perspective view when the rotor and the stator shown in FIG. 1 are separated. An exploded perspective view of the stator portion shown in FIG. Explanatory drawing of stepping motor which concerns on modification 1 of Embodiment 1 of this invention. Explanatory drawing of stepping motor which concerns on modification 2 of Embodiment 1 of this invention. The explanatory view of the stepping motor which concerns on Embodiment 2 of this invention. The explanatory view of the stepping motor which concerns on Embodiment 3 of this invention.

The stepping motor 1 to which the present invention is applied will be described below with reference to the drawings. In the following description, when the direction along the central axis (motor axis) of the rotating shaft 21 is "motor axis direction L", "one side of the motor axis direction L" rotates from the stator portion 3 in the motor axis direction L. The counter-output on the side where the shaft 21 protrudes (output side La), and the "other side in the motor axis direction L" is the side opposite to the side where the rotating shaft 21 protrudes from the stator portion 3 (output side La). The case of the side Lb will be mainly described. Further, in the following description, the radial direction and the circumferential direction about the central axis (motor axis) of the rotating shaft 21 are simply referred to as "diameter direction" and "circumferential direction".

(Overall configuration of stepping motor 1)
FIG. 1 is a perspective view of a stepping motor 1 according to the present invention. FIG. 2 is a perspective view of the stepping motor 1 shown in FIG. 1 when viewed from another direction. FIG. 3 is a cross-sectional view of the stepping motor 1 shown in FIG.

As shown in FIGS. 1, 2, and 3, the stepping motor 1 of this embodiment includes a rotor 2 having a cylindrical permanent magnet 22 on the outer peripheral side of a rotating shaft 21 extending in the motor axis direction L, and a permanent magnet 2. A tubular stator portion 3 is provided so as to face the magnet 22 on the outer side in the radial direction. The rotating shaft 21 is made of a metal material such as stainless steel, brass, or aluminum. The permanent magnet 22 is a bond magnet using rare earth magnetic powder, and N poles and S poles are alternately provided in the circumferential direction.

A first end plate 70 is fixed to the end of the output side La of the stator portion 3 by welding or the like, and the first end plate 70 holds a first bearing 75 that rotatably supports the rotating shaft 21. .. The first bearing 75 has a tubular portion 751 and a large diameter portion 752 whose diameter is expanded from the tubular portion 751 on the output side La, and the tubular portion 751 penetrates the through hole 71 of the first end plate 70. The large diameter portion 752 is in contact with the surface of the output side La of the first end plate 70. In this state, the first bearing 75 is fixed to the first end plate 70 by caulking or the like with respect to the end portion of the counter-output side Lb of the tubular portion 751. In this embodiment, a washer 90 is mounted on the rotating shaft 21 between the permanent magnet 22 and the first bearing 75. Therefore, even when the rotor 2 moves to the output side La, the first bearing 75 and the permanent magnet 22 do not come into contact with each other.

A second end plate 80 is fixed to the end of the counter-output side Lb of the stator portion 3, and a second bearing 85 that rotatably supports the rotating shaft 21 is held in the second end plate 80. The second bearing 85 has a tubular portion 851 and a large diameter portion 852 whose diameter is expanded on the output side La from the tubular portion 851, and the tubular portion 851 penetrates the through hole 81 of the second end plate 80. The large diameter portion 852 is in contact with the surface of the output side La of the second end plate 80. In this state, the second bearing 85 is fixed to the second end plate 80 by caulking or the like with respect to the end of the counter-output side Lb of the tubular portion 851. Here, the outer peripheral portion of the large-diameter portion 852 of the second bearing 85 abuts on the inside of the root portion of the B-phase pole tooth 612B, which will be described later, and the second bearing 85 is positioned in the radial direction. Therefore, the second bearing 85 is properly positioned in the radial direction with reference to the root portion of the B-phase pole tooth 612B. A recess is provided around the through hole 81 on the surface of the second end plate 80 on the anti-output side Lb, and the end of the anti-output side Lb of the tubular portion 851 projects from the second end plate 80 to the anti-output side Lb. You may adopt the aspect which suppresses this.

(Structure of stator portion 3)
FIG. 4 is an exploded perspective view when the rotor 2 and the stator 30 shown in FIG. 1 are separated. FIG. 5 is an exploded perspective view of the stator portion 3 shown in FIG. As will be described below with reference to FIGS. 1, 2, 3, and 4, etc., in the stator portion 3, the first core, the coil bobbin around which the coil is wound, and the second core are aligned in the motor axis direction. Four or more stacked stator sets are arranged in the motor axis direction, and the stator 30 is composed of two adjacent stator sets in the motor axis direction L among the plurality of stator sets. Therefore, in the stator portion 3, a plurality of stators 30 are arranged so as to overlap each other in the motor axis direction L. Therefore, even when the diameter of the stepping motor 1 is reduced, a large torque can be obtained.

In this embodiment, the stator portion 3 is reduced in diameter so that the outer diameter is 6 mm or less. Therefore, each of the plurality of stators 30 has an outer diameter of 6 mm or less. Therefore, in the rotor 2, the outer diameter of the rotating shaft 21 is 1 mm or less. The length of the stator portion 3 in the motor axis direction L has a dimension exceeding 10 mm.

In the present embodiment, the stator portion 3 has four stator sets as a plurality of stator sets. Therefore, the stator portion 3 has two stators 30 as a plurality of stators 30. Therefore, in the following description, of the two stators 30, the stator 30 on the counter-output side Lb in the motor axial direction L is set as the first stator 31, and overlaps the output side La in the motor axial direction L with respect to the first stator 31. The stator 30 is referred to as a second stator 32. In the stepping motor 1 of this embodiment, the plurality of stators 30 have the same configuration such as shape and size. Therefore, the first stator 31 and the second stator 32 have the same configuration. Therefore, when it is not necessary to distinguish between the first stator 31 and the second stator 32 when explaining the stator 30, the first stator 31 and the second stator 32 are simply described as the stator 30.

In the plurality of stators 30, one of the two stator sets is for the A phase and the other is for the B phase. More specifically, each of the plurality of stators 30 has an A-phase stator set 30A and a B-phase stator set 30B that overlaps the A-phase stator set 30A from the counter-output side Lb. In the part 3, the A-phase stator set 30A and the B-phase stator set 30B are alternately arranged. In each of the plurality of stators 30, the A-phase stator set 30A and the B-phase stator set 30B have the same basic structure, but the A-phase stator set 30A and the B-phase stator set 30B are motors. It is arranged in the opposite direction in the axial direction L.

More specifically, as shown in FIGS. 3, 4 and 5, the A-phase stator set 30A is formed into an A-phase coil bobbin 50A around which the A-phase coil 40A is wound and an A-phase coil bobbin 50A. It has a first core 61A for A phase that overlaps from the output side La, and a second core 62A for A phase that overlaps the coil bobbin 50A for A phase from the anti-output side Lb. The A-phase coil bobbin 50A has a cylindrical body portion 53A, a flange portion 51A whose diameter is expanded at the end of the output side La of the body portion 53A, and a flange whose diameter is expanded at the end of the counter-output side Lb of the body portion 53A. It has a portion 52A, and an A-phase coil 40A is wound around the body portion 53A between the flange portion 51A and the flange portion 52A.

In the present embodiment, the A-phase first core 61A includes an annular plate portion 611A (A-phase annular plate portion) that overlaps the flange portion 51A of the A-phase coil bobbin 50A, and a plurality of locations in the circumferential direction of the inner edge of the annular plate portion 611A. It has an A-phase pole tooth 612A bent from the outer edge to the anti-output side Lb, and an A-phase case portion 613A bent from the outer edge of the annular plate portion 611A to the anti-output side Lb. The A-phase second core 62A includes an annular plate portion 621A that overlaps the flange portion 52A of the A-phase coil bobbin 50A, and an A-phase polar tooth that is bent from a plurality of locations in the circumferential direction of the inner edge of the annular plate portion 621A to the output side La. It has 622A and is not provided with a case portion. When the first core 61A for A phase and the second core 62A for A phase configured in this way are superposed on the coil bobbin 50A for A phase, A of the first core 61A for A phase is formed along the inner peripheral surface of the body 53A. The phase A pole teeth 612A and the phase A phase pole teeth 622A of the A phase second core 62A are alternately arranged in the circumferential direction.

The B-phase stator set 30B includes a B-phase coil bobbin 50B in which a B-phase coil 40B is wound, a B-phase first core 61B that overlaps the B-phase coil bobbin 50B from the counter-output side Lb, and a B-phase coil bobbin. The 50B is provided with a B-phase second core 62B that overlaps the output side La. The B-phase coil bobbin 50B has a cylindrical body portion 53B, a flange portion 51B whose diameter is expanded at the end of the counter-output side Lb of the body portion 53B, and a flange whose diameter is expanded at the end of the output side La of the body portion 53B. It has a portion 52B, and a B-phase coil 40B is wound around the body portion 53B between the flange portion 51B and the flange portion 52B.

In the present embodiment, the B-phase first core 61B includes an annular plate portion 611B (B-phase annular plate portion) that overlaps the flange portion 51B of the B-phase coil bobbin 50B, and a plurality of locations in the circumferential direction of the inner edge of the annular plate portion 611B. It has a B-phase pole tooth 612B bent from the outer edge to the output side La, and a B-phase case portion 613B bent from the outer edge of the annular plate portion 611B to the output side La. The B-phase second core 62B has an annular plate portion 621B that overlaps the flange portion 52B of the B-phase coil bobbin 50B and a B-phase pole that is bent from a plurality of locations in the circumferential direction of the inner edge of the annular plate portion 621B to the opposite output side Lb. It has teeth 622B and is not provided with a case portion. When the B-phase first core 61B and the B-phase second core 62B configured in this way are superposed on the B-phase coil bobbin 50B, B of the B-phase first core 61B is placed along the inner peripheral surface of the body 53B. The phase pole teeth 612B and the phase B pole teeth 622B of the B phase second core 62B are alternately arranged in the circumferential direction.

In this embodiment, when the stepping motor 1 is assembled so that the A-phase stator set 30A and the B-phase stator set 30B overlap in the motor axis direction L, the A-phase opening 614A and the B-phase opening 614B, which will be described later, are used. Adjust the angular position around the motor axis with reference to. As a result, in each of the plurality of stators 30, the A-phase pole teeth 612A and 622A and the B-phase pole teeth 612B and 622B are displaced by an angle along a predetermined electric angle. Therefore, when driving the stepping motor 1, the A-phase coil 40A and the B-phase coil 40B are supplied with drive signals that are out of phase by an angle along a predetermined electric angle. Therefore, the accuracy of the stop position of the rotor 2 and the like can be improved.

Further, when assembling the stepping motor 1 so that the A-phase stator set 30A and the B-phase stator set 30B overlap in the motor axis direction L, the A-phase case portion 613A is the A-phase in each of the plurality of stators 30. The second core 62A for the B phase is covered on the radial outer side, and the B phase case portion 613B covers the second core 62B for the B phase on the radial outer side. As a result, the tip portion 615A of the A-phase case portion 613A on the A-phase second core 62A side and the tip portion 615B of the B-phase case portion 613B on the B-phase second core 62B side are in the motor axis direction L. Abut.

Further, when a plurality of stators 30 are overlapped in the motor axis direction L, the first core 61B for the B phase and the first core 61A for the A phase overlap at the boundary portion 35 of the stator 30. More specifically, when the first stator 31 and the second stator 32 are overlapped in the motor axis direction L, at the boundary between the first stator 31 and the second stator 32, the first stator 31 for A phase is used. The core 61A and the B-phase first core 61B of the second stator 32 overlap.

(Structure of terminals, etc.)
In each of the plurality of stators 30, an A-phase terminal block 55A is provided at the outer peripheral end of one of the two flange portions 51A and 52A of the A-phase coil bobbin 50A, and the B-phase coil bobbin 50B A B-phase terminal block 55B is provided at the outer peripheral end of one of the two flanges 51B and 52B. The A-phase terminal block 55A is formed so that a resin-made A-phase terminal pin 56A projects outward in the radial direction. When the coil wire is wound around the A-phase coil bobbin 50A to form the A-phase coil 40A, the terminal is configured by entwining the end of the coil wire with the A-phase terminal pin 56A and then soldering. To. Further, the B-phase terminal block 55B is formed so that the resin-made B-phase terminal pin 56B projects outward in the radial direction. When the coil wire is wound around the B-phase coil bobbin 50B to form the B-phase coil 40B, the terminal is configured by entwining the end of the coil wire with the B-phase terminal pin 56B and then soldering. To.

On the other hand, the A-phase case portion 613A is formed with an A-phase opening 614A extending from the tip portion 615A toward the output side La, and the B-phase case portion 613B is formed on the opposite output side from the tip portion 615B. A B-phase opening 614B is formed which extends toward Lb and forms an opening 614 connected to the A-phase opening 614A. Therefore, even when the diameter of the stepping motor 1 is reduced, the A-phase terminal block 55A and the B-phase terminal block 55B can be projected outward from the opening in the radial direction.

In the present embodiment, the A-phase opening 614A extends over the entire motor axis direction L of the A-phase case 613A, and the B-phase opening 614B extends in the motor axis direction L of the B-phase case 613B. It is widespread throughout. Therefore, as a result of the opening 614 extending over the entire motor axis direction L in each of the plurality of stators 30, when the plurality of stators 30 are stacked in the motor axis direction L, the opening 614 is the motor of the stator portion 3. It extends continuously over the entire axial direction L. Therefore, even when the diameter of the stepping motor 1 is reduced, the two A-phase terminal blocks 55A and the two B-phase terminal blocks 55B can be projected from the opening 614 outward in the radial direction with a margin. it can.

In this embodiment, the A-phase terminal block 55A is provided on the flange portion 52A of the anti-output side Lb of the A-phase coil bobbin 50A, and the B-phase terminal block 55B is the flange portion of the anti-output side Lb of the B-phase coil bobbin 50B. It is provided in 51B. Therefore, the A-phase terminal block 55A and the B-phase terminal block 55B are arranged at sufficient intervals in the motor axial direction L, respectively.

As shown in FIG. 5, the annular plate portion 621A of the second core 62A for the A phase is formed with a protruding portion 628A protruding outward in the radial direction, and the annular plate portion 621B of the second core 62B for the B phase is formed. A protruding portion 628B protruding outward in the radial direction is formed. On the other hand, as shown in FIG. 2, a notch 618A is formed in the tip portion 615A of the A-phase case portion 613A on the side opposite to the A-phase opening 614A, and the tip portion 615B of the B-phase case portion 613B is formed. Is formed with a notch 618B on the side opposite to the B-phase opening 614B. Therefore, the protruding portion 628A of the second core 62A for the A phase and the protruding portion 628B of the second core 62B for the B phase are in a state of being exposed from the notches 618A and 618B in a state of being overlapped in the motor axis direction L.

(Fixed structure at the boundary 35 of the stator 30)
In the stepping motor 1 of this embodiment, the first core 61A for the A phase of the first stator 31 and the first core 61B for the B phase of the second stator 32, which overlap at the boundary 35 of the plurality of stators 30, are fixed by welding. ing. In the present embodiment, the B-phase first core 61B and the A-phase first core 61A that overlap at the boundary portions 35 of the plurality of stators 30 are bent portions between the annular plate portion 611B and the B-phase case portion 613B. It is fixed by welding between the outer surface of the 616B and the outer surface of the bent portion 616A between the annular plate portion 611A and the A-phase case portion 613A. Therefore, the first welding mark 66 when the first core 61B for B phase and the first core 61A for A phase overlapping at the boundary portions 35 of the plurality of stators are fixed by welding is the outer surface of the bent portion 616B. And so as to straddle both the outer surfaces of the bend 616A.

Therefore, in the state of the A-phase first core 61A and the B-phase first core 61B before assembling the A-phase stator set 30A and the B-phase stator set 30B, the boundary portion 35 and the A-phase first core 61A In addition to being able to fix the B-phase first core 61B by welding, even after assembling the A-phase stator set 30A and the B-phase stator set 30B, the A-phase first core 61A and the B-phase first core 61A can be fixed. The core 61B can be fixed by welding at the boundary portion 35.

Here, in the step of manufacturing the first core 61A for A phase and the first core 61B for B phase, the magnetic plate divided into a predetermined shape is drawn by a mold or the like, and the A phase pole tooth 612A , A-phase case portion 613A, B-phase pole tooth 612B, and B-phase case portion 613B are processed so as to stand up from the annular plate portions 611A and 611B. As a result, both the radial outer surface of the bent portion 616A and the radial outer surface of the bent portion 616B become a convex curved surface that is convexly curved toward the radial outer side. Even in such a case, in the present embodiment, the laser beam is irradiated between the bent portion 616A and the bent portion 616B toward the portion where the first core 61B for the B phase and the first core 61A for the A phase are in contact with each other. The first core 61B for the B phase and the first core 61A for the A phase are fixed by laser welding. At that time, since laser welding is performed at a plurality of locations in the circumferential direction, the first welding marks 66 are present at a plurality of locations separated in the circumferential direction. Therefore, the work efficiency can be improved as compared with the case of welding all around.

As described above, in this embodiment, since welding is performed at the portion where the bent portions 616A and 616B formed of the convex curved surface are in contact with each other, when the A-phase case portion 613A is bent from the outer edge of the annular plate portion 611A, and the outer edge of the annular plate portion 611B. When bending the B-phase case portion 613B, it is not necessary to perform a special bending process or additional post-processing so that a convex curved surface is not generated.

Here, in the process of manufacturing the first core 61A for the A phase and the first core 61B for the B phase, the plate thickness of the A phase polar tooth 612A and the B phase polar tooth 612B is increased by utilizing a thinning step or the like. The thickness of the annular plate portions 611A and 611B may be thinner than the plate thickness of the A-phase case portion 613A and the B-phase case portion 613B, and the plate thickness of the A-phase polar tooth 612A and the B-phase polar tooth 612B may be thinner. preferable. In such a configuration, the difference between the plate thickness of the A-phase pole teeth 612A and the B-phase pole teeth 612B and the plate thickness of the annular plate portions 611A and 611B is larger than the wire diameter of the coil wire, and the A-phase case portions 613A and B If the difference between the plate thickness of the phase case portion 613B and the plate thickness of the A-phase pole teeth 612A and the B-phase pole teeth 612B is larger than the wire diameter of the coil wire, a large space for winding the coil wire should be secured. Can be done. Therefore, the number of times the coil wire is wound can be increased, so that the torque can be increased. For example, in this embodiment, the thickness of the annular plate portions 611A and 611B is 0.
It is 35 mm, the plate thickness of the A-phase pole tooth 612A and the B-phase pole tooth 612B is 0.23 mm, and the plate thickness of the A-phase case portion 613A and the B-phase case portion 613B is 0.20 mm. The wire diameter of the coil wire is 0.055 mm.

(Fixed structure in the stator 30, etc.)
In this embodiment, the first core 61A for the A phase and the first core 61B for the B phase are fixed to each of the plurality of stators 30. More specifically, in each of the plurality of stators 30, the first core 61A for the A phase and the first core 61B for the B phase are fixed by welding. In this embodiment, since the tip portion 615A of the A-phase case portion 613A and the tip portion 615B of the B-phase case portion 613B are in contact with each other in the motor axis direction L, the tip portion 615A of the A-phase case portion 613A and the tip portion 615A are in contact with each other. The tip portion 615B of the B-phase case portion 613B is fixed by laser welding. Therefore, in each of the plurality of stators 30, the second welding mark 67 when the first core 61A for the A phase and the first core 61B for the B phase are fixed by laser welding is the tip of the A phase case portion 613A. It exists so as to straddle the radial outer surface of the portion 615A and the radial outer surface of the tip portion 615B of the B-phase case portion 613B. Here, the second welding marks 67 are present at a plurality of locations separated in the circumferential direction. Therefore, the work efficiency can be improved as compared with the case of welding all around.

Further, in the present embodiment, the protruding portion 628A of the second core 62A for the A phase and the protruding portion 628B of the second core 62B for the B phase are overlapped in the motor axis direction L, and the case portions 613A and B for the A phase are overlapped. It is exposed from the notches 618A and 618B of the compatible case portion 613B. Therefore, the protruding portion 628A of the second core 62A for the A phase and the case portion 613A for the A phase can be fixed by laser welding, and the protruding portion 628B and the case portion 613B for the B phase of the second core 62B for the B phase can be fixed. Can be fixed by laser welding.

Regarding the protruding portion 628A of the second core 62A for the A phase and the protruding portion 628B of the second core 62B for the B phase, the second core for the A phase before assembling the stator set 30A for the A phase and the stator set 30B for the B phase. In addition to being able to be fixed by laser welding in the state of the core 62A and the second core 62B for the B phase, the protrusions 628A and 628B are laser welded even after the A-phase stator set 30A and the B-phase stator set 30B are assembled. Can be fixed by.

(Structure of rotor 2)
As shown in FIGS. 3 and 4, in the rotor 2, the permanent magnets 22 are arranged so as to face each of the plurality of stators 30 on the outer side in the radial direction. In the present embodiment, the permanent magnet 22 is composed of a plurality of magnets 220 fixed to the rotating shaft 21 so as to face each of the plurality of stators 30. More specifically, the permanent magnet 22 includes a first magnet 221 facing the first stator 31 and a second magnet 222 facing the second stator 32. Therefore, a magnet that is easier to manufacture and cheaper to manufacture can be used than when a magnet that extends long in the motor axis direction L is used.

In each of the plurality of magnets 220, recesses 226 and 227 are formed on the end face of the non-output side Lb and the end face of the output side La, and the recess 227 is an adhesive for fixing the magnet 220 and the rotating shaft 21. 29 is provided.

(Countermeasures against bending of the rotating shaft 21)
The rotor 2 is provided with a connecting portion 25 for connecting magnets 220 adjacent to each other in the motor axis direction L. In the present embodiment, the connecting portion 25 is a spacer 26 bonded to the end of the magnet 220 by an adhesive 291 between adjacent magnets 220 (first magnet 221 and second magnet 222) in the motor axis direction L. Here, the adhesive 291 may be of the same type as the adhesive 29 for fixing the magnet 220 and the rotating shaft 21, or may be of a different type.

In the present embodiment, the spacer 26 is a disk made of resin or metal, and a shaft hole 260 through which the rotating shaft 21 penetrates is formed. Here, the rotating shaft 21 may be in either a state of being fitted in the shaft hole 260 or a state of being inserted with a gap between the rotating shaft 21 and the shaft hole 260.

According to such a configuration, since the rotor 2 is provided with a connecting portion 25 for connecting the magnets 220 adjacent to each other in the motor axis direction L, the magnetism acting between the stator portion 3 and the permanent magnet 22 It is possible to prevent the rotating shaft 21 from bending between two adjacent magnets 220 when the rotor 2 is rotated by a force or when an impact load is applied. Further, since the connecting portion 25 is a spacer 26 bonded to each of the two magnets 220 by two adjacent magnets 220, the magnet 220 is interposed through the spacer 26 even when the distance between the two adjacent magnets 220 is wide. Can be connected to each other

[Modification 1 of Embodiment 1]
FIG. 6 is an explanatory diagram of the stepping motor 1 according to the first modification of the first embodiment of the present invention. The basic configurations of this example and the embodiments described later are the same as those of the first embodiment. Therefore, the common parts are designated by the same reference numerals and their description will be omitted. In the embodiment shown in FIG. 3, the connecting portion 25 for connecting the magnets 220 to each other is a disk-shaped spacer 26, but in the present embodiment, as shown in FIG. 6, the spacer 26 is formed in the recess 226 of the magnet 220. It has a protruding portion 261 that protrudes toward the magnet 220 and a protruding portion 262 that protrudes toward the inside of the recess 227 of the magnet 220. Therefore, the spacer 26 is also adhered to the magnet 220 by the adhesive 291 even inside the recesses 226 and 227 of the magnet 220. In such an embodiment, the area of the portion of the rotating shaft 21 that is not reinforced from the outside in the radial direction between the two adjacent magnets 220 can be narrowed. Therefore, it is possible to further suppress the rotation shaft 21 from bending between two adjacent magnets 220.

[Modification 2 of Embodiment 1]
FIG. 7 is an explanatory view of the stepping motor 1 according to the second modification of the first embodiment of the present invention. Also in this embodiment, as in the first embodiment, the rotor 2 is provided with a connecting portion 25 for connecting the magnets 220 adjacent to each other in the motor axis direction L. In the present embodiment, the connecting portion 25 is an adhesive layer 295 that adheres adjacent magnets 220 (first magnet 221 and second magnet 222) in the motor axis direction L. The adhesive layer 295 may be of the same type as the adhesive 29 for fixing the magnet 220 and the rotating shaft 21, or may be of a different type.

Even in such a configuration, as in the first embodiment, when the rotor 2 is rotated by the magnetic force acting between the stator portion 3 and the permanent magnet 22, or when an impact load is applied, the two magnets 220 adjacent to each other It is possible to prevent the rotating shaft 21 from bending between them. Further, since the connecting portion 25 is the adhesive layer 295, there is an advantage that it is not necessary to provide the spacer 26 unlike the first embodiment.

[Embodiment 2]
FIG. 8 is an explanatory diagram of the stepping motor 1 according to the second embodiment of the present invention. As shown in FIG. 8, in the present embodiment as well, the permanent magnet 22 of the rotor 2 is composed of a plurality of magnets 220 (first magnet 221 and second magnet 222) arranged in the motor axis direction L as in the first embodiment. .. In the present embodiment, the rotating shaft 21 is equipped with a tubular member 27 extending in the motor axis direction L between adjacent magnets 220 in the motor axis direction L. Therefore, the rotating shaft 21 is reinforced by a tubular member 27 between two adjacent magnets 220. The tubular member 27 may be made of either resin or metal. Further, the tubular member 27 may be attached to or not attached to the rotating shaft 21. In this embodiment, the rotating shaft 21 is press-fitted into the shaft hole 270 of the tubular member 27.

According to such a configuration, since the rotating shaft 21 is reinforced by the tubular member 27 between the two adjacent magnets 220, the rotating shaft 21 bends between the two adjacent magnets 220. It can be suppressed.

[Embodiment 3]
FIG. 9 is an explanatory diagram of the stepping motor 1 according to the third embodiment of the present invention. As shown in FIG. 9, in the present embodiment as well, the permanent magnet 22 of the rotor 2 is composed of a plurality of magnets 220 (first magnet 221 and second magnet 222) arranged in the motor axis direction L, as in the first embodiment. .. In the present embodiment, the rotating shaft 21 is covered with a coating layer 28 between the magnets 220 adjacent to each other in the motor axis direction L. The coating layer 28 is made of a hard resin material.

Therefore, the rotating shaft 21 is reinforced by a coating layer 28 between two adjacent magnets 220. Therefore, it is possible to prevent the rotating shaft 21 from bending between two adjacent magnets 220.

[Other embodiments]
In the above embodiment, in the plurality of stators 30, one of the two stator sets is for the A phase and the other is for the B phase, but a part of the plurality of stators 30 is for the A phase, and the other The present invention may be applied when a part is for B phase. Further, the present invention may be applied to a plurality of stators 30 when the two stator sets are in the same phase.

In the above embodiment, the stator portion 3 is provided with four sets of stator sets, but the present invention may be applied when five or more sets of stator sets are provided.

1 ... stepping motor, 2 ... rotor, 3 ... stator part, 30 ... stator, 21 ... rotating shaft, 22 ... permanent magnet, 25 ... connecting part, 26 ... spacer, 27 ... tubular member, 28 ... coating layer, 30A ... A-phase stator set, 30B ... B-phase stator set, 31 ... 1st stator, 32 ... 2nd stator, 35 ... boundary, 40A ... A-phase coil, 40B ... B-phase coil, 50A ... A-phase Coil bobbin, 50B ... B phase coil bobbin, 61A, 61B ... 1st core, 62A, 62B ... 2nd core, 220 ... magnet, 221 ... 1st magnet, 222 ... 2nd magnet, 291 ... Adhesive, 260, 270 ... Shaft hole, 261,262 ... Projection part, 295 ... Adhesive layer, 611A ... Circular plate part (A-phase annular plate part), 611B ... Circular plate part (B-phase annular plate part), 621A, 621B ... Circular plate Parts, 612A, 622A ... A-phase pole teeth, 612B, 622B ... B-phase pole teeth, 613A ... A-phase case, 613B ... B-phase case, L ... Motor axis direction, La ... Output side, Lb … Non-output side

Claims (10)

A rotor equipped with a permanent magnet on the outer peripheral side of the rotating shaft extending in the direction of the motor axis,
A tubular stator portion arranged so as to face the permanent magnet outward in the radial direction,
Have,
In the stator portion, four or more sets of a first core, a coil bobbin around which a coil is wound, and a stator set in which a second core is overlapped in the motor axis direction are arranged in the motor axis direction.
The permanent magnet is composed of a plurality of magnets arranged in the direction of the motor axis.
A stepping motor characterized in that the rotor is provided with a connecting portion for connecting magnets adjacent to each other in the motor axis direction among the plurality of magnets. In the motor according to claim 1,
A stepping motor, wherein the connecting portion is a spacer adhered to the magnets between magnets adjacent to each other in the motor axis direction among the plurality of magnets. In claim 1,
A stepping motor characterized in that the connecting portion is an adhesive layer that connects magnets adjacent to each other in the motor axis direction among the plurality of magnets. A rotor equipped with a permanent magnet on the outer peripheral side of the rotating shaft extending in the direction of the motor axis,
A tubular stator portion arranged so as to face the permanent magnet outward in the radial direction,
Have,
In the stator portion, four or more sets of a first core, a coil bobbin around which a coil is wound, and a stator set in which a second core is overlapped in the motor axis direction are arranged in the motor axis direction.
The permanent magnet is composed of a plurality of magnets arranged in the direction of the motor axis.
A stepping motor characterized in that a tubular member extending in the motor axis direction is mounted on the rotation shaft between magnets adjacent to each other in the motor axis direction among the plurality of magnets. A rotor equipped with a permanent magnet on the outer peripheral side of the rotating shaft extending in the direction of the motor axis,
A tubular stator portion arranged so as to face the permanent magnet outward in the radial direction,
Have,
In the stator portion, four or more sets of a first core, a coil bobbin around which a coil is wound, and a stator set in which a second core is overlapped in the motor axis direction are arranged in the motor axis direction.
The permanent magnet is composed of a plurality of magnets arranged in the direction of the motor axis.
The rotating shaft is a stepping motor characterized in that, among the plurality of magnets, between magnets adjacent to each other in the motor axis direction are coated with a coating layer. In the motor according to any one of claims 1 to 5,
The stepping motor is characterized in that, among the plurality of stator sets, a plurality of stators composed of two stator sets adjacent to each other in the motor axis direction are arranged in the stator portion in the motor axis direction. In the motor according to claim 6,
In the plurality of stator portions, a stepping motor characterized in that one of the two stator sets is an A-phase stator set and the other is a B-phase stator set. In the motor according to claim 6 or 7,
In each of the plurality of stator sets, the first core is characterized by having a tubular case portion that bends at the outer peripheral edge of an annular plate portion that overlaps the coil bobbin and covers the coil from the radial outside. Stepping motor to do. The stepping motor according to any one of claims 1 to 8.
The outer diameter of the plurality of stators is 6 mm or less,
A stepping motor characterized in that the outer diameter of the rotating shaft is 1 mm or less. The stepping motor according to any one of claims 1 to 9.
The stepping motor is characterized in that the stator portion has four stator sets as the plurality of stator sets.

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