JP2014236531A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor capable of suppressing an excessive load applied from radial bearings, without using a coupling, even if a rotation shaft formed with a spiral groove for a ball screw is supported by the two radial bearings.SOLUTION: A motor 1 has a fixed body 2 including a rotor 40 equipped with a rotation shaft 41, and a stator 30. The fixed body 2 holds an outside radial bearing 15 held at an output side end portion of the fixed body 2, and an opposite output side radial bearing 14. At a part on an output side L1 of the rotation shaft 41, a spiral groove 43 for a ball screw is formed. In the fixed body 2, a bearing holder 50 for holding the output side radial bearing 15 has a bearing holding portion 51, a flange portion 52, and a coupling portion 53 for coupling the flange portion 52 and the bearing holding portion 51. The coupling portion 53 is equipped with an elastically deforming portion 54 capable of elastically deforming by following the inclination of the rotation shaft 41.

Description

  The present invention relates to a motor in which a spiral groove for a ball screw is formed on a rotating shaft.

  The motor includes a rotor having a rotating shaft and a permanent magnet fixed to the outer peripheral surface of the rotating shaft, a fixed body including a stator disposed on the radially outer side of the permanent magnet, and two rotors that rotatably support the rotating shaft. And a radial bearing. Further, in a motor of a type in which a spiral groove for a ball screw is formed in a portion of the rotating shaft that protrudes from the fixed body to the output side, a rotary encoder is provided at the end on the opposite side of the rotating shaft. The angle position of the rotating shaft is monitored (Patent Document 1).

  In the motor described in Patent Document 1, as two radial bearings, a first bearing held by a fixed body and a second bearing that supports the tip of the rotating shaft are used. In addition, as in the motor described in Patent Document 1, when a motor having a ball screw spiral groove formed on the rotation shaft is mounted on a motor device, the rotation shaft is inserted through a nut that engages with the spiral groove. Therefore, the rotary shaft is positioned on the motor device at a total of three locations by the nut and the two bearings. At that time, if the positional accuracy in the direction orthogonal to the three motor axes is low, a load is applied from the bearing to the rotating shaft. Therefore, as described in Patent Document 1, the first shaft in which the spiral groove is formed, the second shaft to which the permanent magnet is fixed, the first shaft and the second shaft are coupled by coupling. Often constitutes a rotating shaft.

Japanese Patent Laid-Open No. 2003-120779

  However, if the rotating shaft is configured by connecting two shafts (first shaft and second shaft) by coupling as in the motor described in Patent Document 1, the rotating shaft becomes longer correspondingly. Moreover, like the motor of patent document 1, when only one radial bearing hold | maintained at the fixed body is used, a rotating shaft tends to incline with respect to a fixed body. For this reason, there is a problem that the friction load of the nut of the ball screw increases.

  In view of the above problems, an object of the present invention is that an extra load is applied from the radial bearing to the rotating shaft even when the rotating shaft on which the spiral groove for the ball screw is formed is supported by two radial bearings. It is in providing the motor which can suppress this without using a coupling.

  In order to solve the above-described problems, a motor according to the present invention includes a rotor including a rotating shaft and a permanent magnet fixed to the rotating shaft, and a fixed body including a stator disposed on the radially outer side of the permanent magnet. An output-side radial bearing held at the output-side end of the fixed body and rotatably supporting the rotary shaft, and held on the fixed body on the opposite side of the output-side radial bearing to the fixed body, and rotates the rotary shaft A non-output-side radial bearing that supports the output shaft, and a spiral groove for a ball screw is formed in a portion of the rotating shaft that protrudes from the fixed body to the output side, and the fixed body includes the output-side radial bearing. And a bearing holder that holds one of the counter-output-side radial bearings, the bearing holder having a bearing holding portion that holds the one radial bearing inside, and a diameter that is larger than that of the bearing holding portion. A flange portion serving as a mounting portion to the motor device on the outer side, and a connecting portion that connects the flange portion and the bearing holding portion, and the connecting portion is elastically deformed following the inclination of the rotating shaft. It has a possible elastic deformation part.

  When the motor according to the present invention is mounted on a motor device, the rotation shaft is positioned on the motor device via a nut that engages with the spiral groove, and the fixed body is attached to the motor device via a flange portion of the bearing holder. Positioned. Accordingly, the rotary shaft is positioned relative to the motor device at a total of three locations by the positioning portion to the motor device via the nut and the two radial bearings (output-side radial bearing and counter-output-side radial bearing). become. At that time, if the positional accuracy in the direction perpendicular to the motor axis at the three locations is low and the concentricity between the rotating shaft and the output side radial bearing or the concentricity between the rotating shaft and the non-output side radial bearing is low Although an extra load is applied to the rotating shaft, the elastic deformation portion provided in the bearing holder that holds one of the output-side radial bearing and the counter-output-side radial bearing has the above concentricity. It deforms so as to absorb the decrease of. Therefore, the concentricity between the rotating shaft and the output-side radial bearing and the concentricity between the rotating shaft and the non-output-side radial bearing are high. Therefore, even if the two shafts are not coupled by coupling to form a rotating shaft, an extra load is not easily applied to the rotating shaft.

  In the present invention, the elastically deformable portion may employ a configuration that is thinner than the flange portion. According to such a configuration, it is easy to provide the elastically deforming portion at the connecting portion.

  In the present invention, the elastic deformation portion may employ a configuration in which a plurality of openings are formed in the circumferential direction. According to such a configuration, it is easy to provide the elastically deforming portion at the connecting portion.

  In the present invention, the bearing holder includes a first plate in which the bearing holding portion is formed, a second plate in which the flange portion is formed and connected to the first plate at a portion overlapping the first plate, The second plate may be configured to include the elastic deformation portion on a radially outer side than a portion connected to the first plate.

  In the present invention, it is preferable that the one radial bearing is the output-side radial bearing, and a rotary encoder that detects the rotation of the rotary shaft is provided on the counter-output side of the counter-output-side radial bearing. . According to such a configuration, since the concentricity between the non-output-side radial bearing and the rotary encoder is high, the detection accuracy of the rotary encoder is high.

  According to the present invention, the rotary encoder is a magnetic rotary encoder, and the magnetic rotary encoder is provided on an encoder magnet fixed to an end portion of the rotating shaft, and is provided on the fixed body side. The encoder magnet is effective when applied in the case where a pair of N and S poles are formed on the surface facing the magnetosensitive element. . In such a configuration, when the positional accuracy between the encoder magnet provided on the rotating shaft side and the magnetic sensing element on the fixed body side is low, the detection accuracy is greatly reduced, so the effect of applying the present invention is great. is there.

  When the motor according to the present invention is mounted on a motor device, the rotation shaft is positioned on the motor device via a nut that engages with the spiral groove, and the fixed body is attached to the motor device via a flange portion of the bearing holder. Positioned. Therefore, the rotating shaft is positioned with respect to the motor device at a total of three positions by the positioning portion to the motor device through the nut and the two radial bearings (the output side radial bearing and the non-output side radial bearing). become. At that time, if the positional accuracy in the direction perpendicular to the motor axis at the three locations is low and the concentricity between the rotating shaft and the output side radial bearing or the concentricity between the rotating shaft and the non-output side radial bearing is low Although an extra load is applied to the rotating shaft, the elastic deformation portion provided in the bearing holder that holds one of the output-side radial bearing and the counter-output-side radial bearing has the above concentricity. It is deformed so as to absorb the lowering, and the concentricity between the rotating shaft and the output-side radial bearing and the concentricity between the rotating shaft and the non-output-side radial bearing become high. Therefore, even if the two shafts are not coupled by coupling to form a rotating shaft, an extra load is not easily applied to the rotating shaft.

It is explanatory drawing which shows the external appearance etc. of the motor to which this invention is applied. It is sectional drawing which shows a mode that the motor to which this invention was applied was cut | disconnected in the position which passes along a motor axis line. It is explanatory drawing which shows the principle in the rotary encoder provided in the motor to which this invention is applied. It is a perspective view of a bearing holder or the like of a motor to which the present invention is applied. It is a disassembled perspective view of the bearing holder etc. of the motor to which this invention is applied. It is explanatory drawing of the 2nd plate used for the bearing holder of the motor to which this invention is applied.

  Hereinafter, a motor according to an embodiment of the present invention will be described with reference to the drawings.

(overall structure)
FIG. 1 is an explanatory view showing the appearance and the like of a motor to which the present invention is applied. FIGS. 1A and 1B are a perspective view of the motor viewed from the output side, and the motor cut at a position passing through the motor axis. FIG. FIG. 2 is a cross-sectional view showing a state where a motor to which the present invention is applied is cut at a position passing through the motor axis.

  The motor 1 shown in FIGS. 1 and 2 is a permanent magnet type synchronous motor having a relatively large output torque. The motor 1 includes a motor housing 10, a cylindrical stator 30 configured inside the motor housing 10, a rotor 40 disposed inside the stator 30, and the like, and is fixed by the motor housing 10 and the stator 30. 2 is configured. The fixed body 2 has a bearing holder 50 and the like which will be described later.

  In the fixed body 2, the motor housing 10 has a cylindrical first case 11 and a rectangular tube shape that is adjacent to the first case 11 on the output side L1 from the counter-output side L2 in the motor axis L direction toward the output side L1. The second case 12 and the third case 13 having a rectangular tube shape adjacent to the second case 12 on the output side L1. In connecting the first case 11 and the second case 12, the end of the second case 12 on the opposite side L2 is fitted inside the end of the first case 11 on the output side L1, and welding or the like is performed in this state. Is done. Further, when connecting the second case 12 and the third case 13, the end of the output side L1 of the second case 12 is fitted inside the end of the opposite side L2 of the third case 13, and in this state Welding or the like is performed.

  Further, the motor 1 has a rotary encoder 60 for detecting the rotational speed and angular position of the rotor 40 at the end of the counter-output side L2, and the fixed body 2 is connected to the counter-output side L2 of the motor housing 10. An attached encoder cover 70 is provided.

(Configuration of rotor 40)
The rotor 40 is connected to the rotary shaft 41 via the rotary shaft 41 extending in the motor axis L direction, the cylindrical yoke 46 fixed to the intermediate position of the rotary shaft 41 in the motor axis L direction, and the yoke 46. And a cylindrical permanent magnet 47. In this embodiment, the yoke 46 has a large diameter portion 461 at a position from the output side L1 in the motor axis L direction, and the permanent magnet 47 has a large diameter portion at the end of the output side L1 in the motor axis L direction. It is fixed to the yoke 46 in contact with the 461.

  In the rotary shaft 41, a spiral groove 43 for a feed screw with which the nut 3 engages is formed on the outer peripheral surface of a portion 42 protruding from the end portion (bearing holder 50) of the output side L1 of the fixed body 2 to the output side L1. Is formed.

(Configuration of radial bearing and second case 12)
The motor 1 has a counter-output-side radial bearing 14 held inside the second case 12 and an output-side radial bearing 15 provided at the end of the output side L1 of the third case 13. In the present embodiment, the second case 12 includes a rectangular tube part 121 that constitutes a part of the housing 10, a bottom plate part 122 that is bent radially inward from the opposite end L2 of the rectangular tube part 121, and a bottom plate part A cylindrical portion 123 bent from the radially inner end of 122 to the output side L1, and an annular portion 124 bent radially inward from the output side L1 of the cylindrical portion 123. An opening 145 through which the rotation shaft 41 passes is formed in 124.

  A non-output side radial bearing 14 is disposed between the cylindrical portion 123 and the rotating shaft 41. In this embodiment, the non-output side radial bearing 14 is disposed between the inner ring 141 fixed to the rotating shaft 41, the outer ring 142 held by the cylindrical portion 123 of the second case 12, and the inner ring 141 and the outer ring 142. Bearing ball 143. Accordingly, the second case 12 functions as a bearing holder that holds the counter-output-side radial bearing 14. The inner ring 141 is restricted from moving to the output side L1 by the step portion 419 formed on the rotating shaft 41, and the nut 149 fixed to the thread groove 418 of the rotating shaft 41, and between the nut 149 and the inner ring 141, The movement to the non-output side L2 is restricted by a cylindrical spacer 148 sandwiched between the two.

  The output side radial bearing 15 is held by a bearing holder 50 located at the end of the output side L1 of the fixed body 2, and the detailed configuration of the bearing holder 50 will be described later.

(Configuration of stator 30)
The stator 30 includes an annular stator core 32 having a plurality of salient poles 31 projecting radially inwardly at equal angular intervals, and a drive coil 33 wound around each salient pole 31 via an insulating member 37. It is held on the inner peripheral surface of the third case 13. In addition, the outer peripheral surface of the salient pole 31 is in a state where a slight gap is left in the outer peripheral surface of the permanent magnet 47. The stator core 32 is fixed to the inside of the third case 13 by a method such as shrink fitting, and the third case 13 functions as a yoke.

(Configuration of brake device 70)
The inside of the first case 11 is a brake chamber 110, and an electromagnetic brake unit 80 is disposed in the brake chamber 110.

(Schematic configuration of the rotary encoder 60)
FIG. 3 is an explanatory diagram showing the principle of the rotary encoder 60 provided in the motor 1 to which the present invention is applied. FIGS. 3 (a), 3 (b) and 3 (c) show the signal processing system for the magnetosensitive element 64 and the like. It is explanatory drawing, explanatory drawing of the signal output from the magnetic sensing element 64, and explanatory drawing which shows the relationship between this signal and the angular position (electrical angle) of the rotating shaft 41.

  As shown in FIG. 1B and FIG. 2, a magnetic rotary encoder 60 that monitors the rotation speed and rotation angle of the rotor 40 is configured at the end of the rotation shaft 41 on the opposite output side L2. The rotary encoder 60 includes an encoder magnet 61 fixed to the rotary shaft 41 via a bush 49 and a magnetic sensor unit 65 including a magnetosensitive element 64 (see FIG. 3 and the like) such as a magnetoresistive element. The encoder magnet 61 rotates integrally with the rotating shaft 41. In this embodiment, a shield member 68 is fixed to the first case 11, and the shield member 68 covers a portion where the encoder magnet 61 and the magnetosensitive element 64 are disposed. The magnetic sensor unit 65 is held by a shield member 68.

  As shown in FIG. 3A, a pair of N pole and S pole is formed in the circumferential direction on the surface of the encoder magnet 61 facing the magnetic sensor unit 65. The magnetic sensor unit 65 includes a magnetosensitive element 64 that faces the magnetized surface of the encoder magnet 61 on one side in the motor axis L direction, a control unit 690 that performs processing to be described later, and the like. Further, the rotary encoder 60 has a first hall element 661 and a second hall element located at a position shifted by 90 ° in the circumferential direction with respect to the first hall element 661 at a position facing the magnet 61 for the encoder. 662.

  The magnetic sensing element 64 includes a two-phase magnetic sensitive film (A phase (SIN) magnetic sensitive film and a B phase (COS) having a phase difference of 90 ° with respect to the phase of the sensor substrate 640 and the encoder magnet 61. Magnetoresistive film). In the magnetosensitive element 64, the A phase magnetosensitive film includes a + A phase (SIN +) magnetosensitive film 643 that detects movement of the rotating shaft 41 with a phase difference of 180 °, and a −A phase (SIN−) sensitivity. The B-phase magnetosensitive film includes a + B-phase (COS +) magnetosensitive film 644 that detects the movement of the rotating shaft 41 with a phase difference of 180 °, and a −B-phase (COS−) magnetic film 641. A magnetosensitive film 642 is provided.

  The + A phase magnetosensitive film 643 and the −A phase magnetosensitive film 641 constitute a bridge circuit, and the midpoint position of the + A phase magnetosensitive film 643 and the midpoint position of the −A phase magnetosensitive film 641. Are provided with output terminals. Similarly to the + A-phase sensitive film 644 and the -A-phase sensitive film 641, the + B-phase sensitive film 644 and the -B-phase sensitive film 642 also constitute a bridge circuit. Output terminals are provided at the midpoint position of the magnetosensitive film 644 and at the midpoint position of the -B phase magnetosensitive film 642.

  In the rotary encoder 60 of this embodiment, the magnetosensitive element 64, the first Hall element 661, and the second Hall element 662 include amplifier circuits 691, 692, 695, and 696, and amplifier circuits 691, 692, 695, and 696. A control unit 690 including a CPU (arithmetic circuit) that performs interpolation processing and various arithmetic processing on the sine wave signals sin and cos output from the magnetic sensor 64, the first hall element 661, and the first hall element 661 is configured. Based on the output from the two-hole element 662, the rotation angle position of the rotation shaft 41 with respect to the fixed body is obtained.

More specifically, in the rotary encoder 60, when the rotating shaft 41 makes one rotation, the sine wave signals sin and cos shown in FIG. 3B are output from the magnetosensitive element 64 (magnetoresistance element) for two cycles. Is done. Therefore, after the sine wave signals sin and cos are amplified by the amplifier circuits 691 and 692, the control unit 690 obtains a Lissajous diagram shown in FIG. 3C, and θ = tan ⁻¹ (sin from the sine wave signals sin and cos. / Cos), the angular position θ of the rotating shaft 41 can be obtained. In this embodiment, the first Hall element 661 and the second Hall element 662 are arranged at a position shifted by 90 ° from the center of the encoder magnet 61. For this reason, the combination of the outputs of the first Hall element 661 and the second Hall element 662 indicates which section of the sine wave signal sin or cos the current position is located. Accordingly, the rotary encoder 60 generates absolute angular position information of the rotating body 2 based on the detection result of the magnetic sensitive element 64, the detection result of the first Hall element 661, and the detection result of the second Hall element 662. The absolute operation can be performed.

(Configuration of output-side radial bearing 15 and bearing holder 50)
FIG. 4 is a perspective view of a bearing holder of a motor to which the present invention is applied. FIGS. 4A and 4B are a perspective view of the bearing holder and the like viewed from the output side, and a reverse output of the bearing holder and the like. It is the perspective view seen from the side. FIG. 5 is an exploded perspective view of a bearing holder of a motor to which the present invention is applied. FIGS. 5A and 5B are an exploded perspective view of the bearing holder and the like as viewed from the output side, and a bearing holder and the like. It is the disassembled perspective view seen from the non-output side. FIG. 6 is an explanatory view of the second plate used in the bearing holder of the motor to which the present invention is applied, and FIGS. 6 (a), (b), (c), and (d) are plan views of the second plate. FIG. 4 is a bottom view, a side view, and a cross-sectional view.

  1 and 2 again, the output-side radial bearing 15 is composed of two ball bearings 156, 157 arranged in the direction of the motor axis L, and each of the ball bearings 156, 157 is fixed to the rotating shaft 41. It has an inner ring 151, an outer ring 152 held by the bearing holder 50, and a bearing ball 153 disposed between the inner ring 151 and the outer ring 152.

  In holding the output-side radial bearing 15, the fixed body 2 has a bearing holder 50. The bearing holder 50 includes a bearing holding portion 51 in which the output-side radial bearing 15 is held inside, a flange portion 52 that serves as an attachment portion to a motor device on a radially outer side from the bearing holding portion 51, and the flange portion 52 and the bearing holding. And a through hole 520 through which a bolt passes when the motor 1 is mounted on a motor device. In this embodiment, the bearing holding portion 51 is a through-hole penetrating in the motor axis L direction, and the output holding radial bearing 15 is included in the bearing holding portion 51 in a state where the output holding radial bearing 15 is accommodated in the bearing holding portion 51. A ring 92 is fitted on the output side L1.

  As shown in FIGS. 4, 5, and 6, in this embodiment, the bearing holder 50 uses a first plate 56 in which a bearing holding portion 51 is formed and a second plate 57 in which a flange portion 52 is formed. The first plate 56 is disposed so as to overlap the opposite output side L <b> 2 of the second plate 57. Here, the first plate 56 and the second plate 57 are connected by a bolt 91 at a portion where the first plate 56 and the second plate 57 overlap in the motor axis L direction. Therefore, in the bearing holder 50, the connecting portion 53 is configured by a portion other than the bearing holding portion 51 of the first plate 56 and a portion other than the flange portion 52 of the second plate 57.

  The first plate 56 includes a substantially rectangular plate-like portion 561 and a cylindrical portion 565 that protrudes from the output-side L1 surface of the plate-like portion 561 to the output side L1, and the plate-like portion 561 has a cylindrical portion 565. An annular thick portion 562 is formed around. In addition, arc-shaped notches 563 are formed at four corners of the plate-like portion 561. A through hole 567 is formed inside the cylindrical portion 565, and the bearing holding portion 51 is constituted by a portion of the through hole 567 located on the counter-output side L2. Further, on the surface of the output side L1 of the plate-like portion 561, the thick portion 562 is formed with a screw hole 564 around which the bolt 91 is fixed around the cylindrical portion 565.

  An annular thick portion 568 is formed around the through hole 567 on the surface of the plate-like portion 561 on the counter-output side L2, and the inner edge of the counter-output side L2 of the thick portion 562 is the through-hole 567. A receiving portion 569 that protrudes more radially inward and receives the output-side radial bearing 15 on the non-output side L2 is formed.

  The second plate 57 has a substantially rectangular plate shape, and four corners are flange portions 52 that protrude radially outward from the notches 563 of the first plate 56. A through hole 520 is formed in the flange portion 52. A through hole 570 into which the cylindrical portion 565 of the first plate 56 is fitted when the first plate 56 and the second plate 57 are overlapped is formed at the center of the second plate 57, and the cylindrical portion 565 is the through hole 570. The end portion of the cylindrical portion 565 on the output side L1 is slightly protruded from the second plate 57 to the output side L1.

  An annular groove 576 is formed around the through hole 570 on the output side L1 surface of the second plate 57, and an annular shape is formed on the surface opposite to the output side L2 of the second plate 57 at a position overlapping the groove 576. Groove 577 is formed. For this reason, the bottom portion of the groove 576 (the bottom portion of the groove 577) is a thin plate portion 578 whose dimension (thickness) in the motor axis L direction is thinner than the flange portion 52. In addition, circular openings 579 that penetrate the thin plate portion 578 are formed in the thin plate portion 578 at equiangular intervals at a plurality of locations in the circumferential direction. The radially inner sides of the grooves 576 and 577 are annular thick portions 571, and the radially outer sides of the grooves 576 and 577 are frame-like thick portions 572.

  The thick portion 571 on the radially inner side and the thick portion 572 on the radially outer side have the same thickness, but the thick portion 571 is located on the output side L1 from the thick portion 572. In the thick portion 571, stepped through holes 573 through which the bolts 91 are passed are formed at a plurality of positions in the circumferential direction at positions overlapping the screw holes 564 of the first plate 56.

  As described above, in the bearing holder 50 of this embodiment, the thin plate portion 578 is formed in the second plate 57, and the opening portions 579 are formed in the thin plate portion 578 at equal angular intervals. For this reason, the bearing holder 50 is elastic to follow the inclination of the rotating shaft by the thin plate portion 578 in which the opening portion 579 is formed in the connecting portion 53 that connects the bearing holding portion 51 and the flange portion 52. A deformable elastic deformation portion 54 is formed.

  Here, the thick part 572 of the second plate 57 is fixed to the motor device as the flange part 52 at the corner, while the thick part 568 of the first plate 56 is the end part of the output side L1 of the third case. Welding or the like is performed in a state of being fitted inside. Therefore, the position of the bearing holding portion 51 relative to the fixed body 2 such as the housing 10 is fixed, but the position of the flange portion 52 relative to the fixed body 2 such as the housing 10 can be shifted by the elastic deformation portion 54.

(Main effects of this form)
As described above, in the motor 1 of the present embodiment, the spiral shaft 43 for the ball screw is formed on the rotating shaft 41, and the output side radial bearing 15 and the non-output side radial bearing 14 are held on the fixed body 2. Yes. Therefore, when the motor 1 is mounted on the motor device, the rotating shaft 41 is positioned on the motor device via the nut 3 that engages with the spiral groove 43, and the fixed body 2 holds the output-side radial bearing 15. The motor device is positioned through the flange portion 52 of the bearing holder 50 to be operated. Therefore, the rotating shaft 41 is located at three locations in total with respect to the motor device by the positioning portion to the motor device via the nut 3 and the two radial bearings (the output side radial bearing 15 and the counter output side radial bearing 14). Will be positioned. At that time, the positional accuracy in the direction perpendicular to the motor axis L at the three locations is low, and the concentricity of the rotating shaft 41 and the output side radial bearing 15 or the same between the rotating shaft 41 and the non-output side radial bearing 14. If the core is low, an extra load is applied to the rotating shaft 41. However, the elastic deformation portion 54 provided in the bearing holder 50 is deformed to absorb the decrease in the concentricity, and the rotating shaft The concentricity between the output shaft 41 and the output-side radial bearing 15 and the concentricity between the rotary shaft 41 and the non-output-side radial bearing 14 become high.

  For example, if the position of the bearing holder 50 in the fixed body 2 is deviated, the position of the output side radial bearing 15 is deviated. In such a case, the elastic deformation portion 54 provided in the bearing holder 50 is changed. The bearing holding portion 51 is deformed so as to have an appropriate posture with respect to the rotating shaft 41, and the positional deviation of the output-side radial bearing 15 is absorbed. As a result, the concentricity between the rotating shaft 41 and the output side radial bearing 15 is high.

  Therefore, an extra load is not easily applied to the rotating shaft 41 even if the rotating shaft 41 is not configured by connecting the two shafts by coupling. Therefore, the cost of the motor 1 can be reduced as much as the coupling is not used, and the rotating shaft 41 can be shortened.

  The elastic deformation portion 54 is configured by a thin plate portion 578 having a thickness smaller than that of the flange portion 52, and a plurality of openings 579 are formed in the elastic deformation portion 54 (thin plate portion 578) in the circumferential direction. Has been. For this reason, it is easy to provide the elastic deformation part 54 in the connection part 53 of the bearing holder 50.

  Further, a rotary encoder 60 that detects the rotation of the rotary shaft 41 is provided on the counter-output side L2 from the counter-output side radial bearing 14, but the fixed body 2 includes two radial bearings (the output-side bearing 15 and the counter-axis side bearing 15). Since the output side radial bearing 14) is held, the rotating shaft 41 is not easily tilted. Further, since the counter-output side radial bearing 14 and the rotary encoder 60 are positioned with reference to the fixed body 2, the concentricity between the counter-output side radial bearing 14 and the rotary encoder 60 is high. Therefore, the detection accuracy of the rotary encoder 60 is high. In particular, in this embodiment, the rotary encoder 60 is a magnetic rotary encoder, and the encoder magnet 61 has a configuration in which a pair of N pole and S pole is formed on the surface facing the magnetosensitive element 64. Therefore, when the positional accuracy between the encoder magnet 61 provided on the rotating shaft 41 side and the magnetosensitive element 64 on the fixed body 2 side is low, the origin of the Lissajous diagram shown in FIG. However, according to this embodiment, the concentricity between the non-output-side radial bearing 14 and the rotary encoder 60 is high. Therefore, even when the magnetic rotary encoder is used, the detection accuracy of the rotary encoder 60 is high.

(Other embodiments)
In the above embodiment, the elastic deformation portion 54 is provided in the bearing holder 50 that holds the output-side radial bearing 15, but the elastic deformation portion and the second case 12 (bearing holder) that holds the counter-output-side radial bearing 14 are provided. A flange portion may be provided.

  The number, size, and shape of the openings 579 (holes) formed to constitute the elastic deformation portion 54 are of a property that is optimally set according to the amount of deformation required for the elastic deformation portion 54, The configuration is not limited to that shown in FIG.

  In the above embodiment, an example in which the present invention is applied to a permanent magnet type synchronous motor has been described. However, for example, the present invention is applied to other synchronous motors such as a stepping motor and an electromagnetic synchronous motor, induction motors, commutator motors, and other motors. The present invention may be applied.

DESCRIPTION OF SYMBOLS 1 ... Motor 2 ... Fixed body 10 ... Housing 14 ... Anti-output side radial bearing 15 ... Output side radial bearing 30 ... Stator 40 ... Rotor 41 ... Rotating shaft 50 ... Bearing holder 51 ·· Bearing holding portion 52 · · Flange portion 53 · · Connection portion 54 · · Elastic deformation portion · · · First plate 57 · · Second plate 60 · · Rotary encoder 61 · · Encoder magnet 64 · · Magnetosensitive Element 578 .. Thin plate portion 579 .. Opening

Claims (6)

A rotor including a rotating shaft and a permanent magnet fixed to the rotating shaft;
A stationary body including a stator disposed on the radially outer side of the permanent magnet;
An output-side radial bearing held at the output-side end of the fixed body and rotatably supporting the rotating shaft;
A non-output-side radial bearing that is held on the fixed body on the counter-output side from the output-side radial bearing, and rotatably supports the rotating shaft;
Have
A spiral groove for a ball screw is formed in a portion of the rotating shaft that protrudes from the fixed body to the output side,
The fixed body includes a bearing holder that holds one of the output-side radial bearing and the counter-output-side radial bearing.
The bearing holder includes a bearing holding portion in which the one radial bearing is held inside, a flange portion serving as a mounting portion to a motor device at a radially outer side from the bearing holding portion, the flange portion, and the bearing holding portion. And a connecting part for connecting
The motor is characterized in that the connecting portion includes an elastically deformable portion that can be elastically deformed following the inclination of the rotation shaft.   The motor according to claim 1, wherein the elastically deforming portion is thinner than the flange portion.   The motor according to claim 1, wherein a plurality of openings are formed in the elastic deformation portion in a circumferential direction. The bearing holder includes a first plate in which the bearing holding portion is formed, and a second plate in which the flange portion is formed and connected to the first plate at a portion overlapping the first plate,
4. The motor according to claim 1, wherein the second plate includes the elastically deforming portion on a radially outer side than a portion connected to the first plate. 5. The one radial bearing is the output-side radial bearing,
5. The motor according to claim 1, wherein a rotary encoder that detects rotation of the rotary shaft is provided on a side opposite to the output side from the counter output side radial bearing. 6. The rotary encoder is a magnetic rotary encoder,
The magnetic rotary encoder includes an encoder magnet fixed to an end of the rotating shaft, and a magnetosensitive element that is provided on the fixed body side and faces the encoder magnet in the motor axial direction.
The motor according to claim 5, wherein the encoder magnet has a pair of N and S poles formed on a surface facing the magnetosensitive element.

Images