JP2021151002A - Direct drive motor - Google Patents

Abstract

To provide a direct drive motor which makes grease of a bearing less likely to be discharged to the outside without increasing the number of components.SOLUTION: A direct drive motor includes: a first housing; a bearing fitted on the first housing; an outer shaft fitted on the bearing; and an angle detector. The first housing has a first protruding part which contacts with an end surface of an inner ring. The output shaft has: a second protruding part which contacts with an end surface of an outer ring; and a large diameter cylinder part extending in an opposite direction of the outer ring. The first protruding part has a first attachment surface located at the opposite side of a first contact surface which contacts with the inner ring. The second protruding part has a second attachment surface which is located at the opposite side of a second contact surface which contacts with the outer ring and closer to the bearing than the first attachment surface. The angle detector has: a sensor substrate which is attached to the first attachment surface and covers the second attachment surface; and a rotating body which is attached to the second attachment surface and faces the sensor substrate. An outer edge of the sensor substrate is located close to an inner peripheral surface of the large diameter cylinder part.SELECTED DRAWING: Figure 2

Description

The present invention relates to a direct drive motor.

A direct drive motor is an electric motor that directly transmits the generated power to an object without going through a reduction mechanism. As shown in Patent Document 1 below, such a direct drive motor includes a housing, an output shaft rotatably supported by the housing, and an angle detection device. Then, the rotation angle of the output shaft is detected by the angle detection device, and the direction and position of the object are grasped.

By the way, a bearing is interposed between the housing and the output shaft, and the housing and the output shaft are not in contact with each other. That is, a gap extending parallel to the output shaft is provided between the output shaft and the housing. Then, the grease inside the bearing may leak to the outside of the direct drive motor through the gap between the output shaft and the housing. In the direct drive motor of Patent Document 1 below, protrusions are provided on a fixing member for fixing the bearing and a housing to cover the gap between the outer ring and the inner ring of the bearing. Therefore, it is difficult for grease to flow out into the gap between the output shaft and the housing.

Japanese Unexamined Patent Publication No. 2014-75879

According to the structure of Patent Document 1, when the grease exceeds the fixing member or the protrusion, the grease easily flows out to the outside of the direct drive motor. On the other hand, if a new seal for preventing leakage is provided, the number of parts will increase. In addition, it is necessary to secure a space for arranging the seal, and the direct drive motor becomes larger in the axial direction. Therefore, it is desired that the grease of the bearing is less likely to be discharged to the outside while utilizing the existing parts used in the direct drive motor.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a direct drive motor in which grease of a bearing is hard to be discharged to the outside without increasing the number of parts.

In order to achieve the above object, in the direct drive motor according to one aspect of the present disclosure, a housing having a first housing and a second housing surrounding the outer periphery of the first housing, and an inner ring are externally fitted to the first housing. A bearing, a tubular output shaft outerly fitted to the outer ring of the bearing, a rotor outerly fitted to the output shaft, a stator fitted internally to the second housing, and a rotation angle of the output shaft. It is provided with an angle detection device for detecting. The first housing has a first fitting surface on which the inner ring is externally fitted, and a first protruding portion that projects radially outward from the first fitting surface and abuts on the end surface of the inner ring. The output shaft has a second fitting surface into which the outer ring is internally fitted, a second protruding portion that projects radially inward from the second fitting surface and abuts on the end surface of the outer ring, and the inner diameter is the first. (2) It has a large-diameter tubular portion that is formed to have a diameter larger than the inner diameter of the protruding portion and extends in the direction opposite to the outer ring. The first protruding portion has a first contact surface that comes into contact with the inner ring and a first mounting surface that is located on the side opposite to the first contact surface. The second protruding portion is located on the side opposite to the second contact surface and the second contact surface that abuts on the outer ring, and is located closer to the bearing than the first mounting surface. Has a mounting surface. The angle detection device has a magnetic sensor, a ring-shaped sensor substrate that is mounted on the first mounting surface and covers the second mounting surface, and a permanent magnet, and is mounted on the second mounting surface. It has a ring-shaped rotating body facing the sensor substrate. The outer edge of the sensor substrate is close to the inner peripheral surface of the large-diameter tubular portion.

Bearing grease must pass through the gap between the first protrusion and the second protrusion, the gap between the rotating body and the sensor board, and the gap between the outer edge of the sensor board and the large-diameter cylinder, or a direct drive. It is not discharged to the outside of the motor. Here, the gap between the rotating body and the sensor substrate extends in the radial direction, and the path is longer than in the case where it extends in the axial direction. Further, the gap between the outer edge of the sensor substrate and the large-diameter cylinder portion is very small. Therefore, it is difficult for the grease to pass through the gap between the rotating body and the sensor substrate and the gap between the outer edge of the sensor substrate and the large-diameter cylinder portion. Therefore, the grease is less likely to be discharged to the outside of the direct drive motor than the conventional direct drive motor. Further, the above-mentioned path is made by the first housing, the output shaft, and the angle detection device, and does not utilize new parts. Therefore, the increase in the number of parts can be suppressed. In addition, it is possible to avoid increasing the size of the direct drive motor in the axial direction.

As one aspect of the direct drive motor, a ring-shaped first spacer interposed between the first mounting surface and the sensor substrate, and a ring-shaped first spacer interposed between the second mounting surface and the rotating body. It is preferable to include the second spacer of the above.

As one aspect of the direct drive motor, it is preferable that the rotating body has a cylindrical drawing portion that enters between the first protruding portion and the second protruding portion from the inner edge.

The gap between the first protruding portion and the second protruding portion is narrowed by the throttle portion, and it becomes difficult for the grease of the bearing to pass through. Therefore, the possibility that grease is discharged to the outside of the direct drive motor is further reduced.

As one aspect of the direct drive motor, the first housing includes a small-diameter tubular portion extending from the inner edge of the first protruding portion in a direction opposite to the bearing. It is preferable to provide a cover that is attached to the end surface of the small-diameter tubular portion, extends outward in the radial direction, and has an outer edge close to the inner peripheral surface of the large-diameter tubular portion.

Even after passing through the gap between the outer edge of the sensor board and the large-diameter cylinder portion, it is not discharged to the outside unless it passes through the gap between the cover and the large-diameter cylinder portion. Therefore, the possibility that grease is discharged to the outside of the direct drive motor is further reduced.

As one aspect of the direct drive motor, the first housing has an intake hole that is sucked by a suction device. It is preferable that an opening of the intake hole is provided on the outer peripheral surface of the first protruding portion, and the opening extends in the circumferential direction along the outer peripheral surface of the first protruding portion.

According to the above configuration, the grease flowing into the gap between the first protruding portion and the second protruding portion is sucked into the suction device through the intake hole. Therefore, the possibility that grease is discharged to the outside of the direct drive motor is further reduced.

According to the direct drive motor of the present invention, the number of parts does not increase. In addition, it is difficult for the grease of the bearing to be discharged to the outside.

FIG. 1 is a schematic cross-sectional view showing a main configuration of the direct drive motor of the first embodiment. FIG. 2 is an enlarged view of the vicinity of the first housing, the bearing device, the output shaft, and the angle detection device of FIG. FIG. 3 is an enlarged view of the vicinity of the first protrusion, the second protrusion, and the angle detection device of FIG. FIG. 4 is a schematic cross-sectional view showing a main configuration of the direct drive motor of the second embodiment. FIG. 5 is an enlarged view of the vicinity of the first protruding portion of FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments for carrying out the following inventions (hereinafter referred to as embodiments). In addition, the components in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, that is, those in a so-called equal range. Further, the components disclosed in the following embodiments can be appropriately combined.

(First Embodiment)
FIG. 1 is a cross-sectional view showing an outline of a direct drive motor according to the first embodiment. FIG. 2 is an enlarged view of the vicinity of the first housing, the bearing device, the output shaft, and the angle detection device of FIG. FIG. 3 is an enlarged view of the vicinity of the first protrusion, the second protrusion, and the angle detection device of FIG.

The direct drive motor 100 of the first embodiment is fixed to the base 101. Further, the direct drive motor 100 is equipped with a stage 102 on which a transported object is loaded. The direct drive motor 100 is an electric motor that rotates the stage 102 without going through a speed reducer and conveys the conveyed object.

The direct drive motor 100 includes a housing 1 installed on the base 101, a bearing device 20, an output shaft 30, a rotor 40, a stator 41, a cover 50, and an angle detection device 60. Hereinafter, the direction parallel to the axis X of the output shaft 30 is referred to as the axis X direction. Further, among the axis X directions, the direction in which the stage 102 is arranged as viewed from the direct drive motor 100 is referred to as the first direction X1, and the direction in which the platform 101 is arranged as viewed from the direct drive motor 100 is referred to as the second direction X2. ..

The housing 1 includes a first housing 2, a second housing 3 surrounding the outer periphery of the first housing 2, and a base portion 4 arranged between the first housing 2 and the second housing 3. The first housing 2 has a cylindrical shape centered on the axis X. As shown in FIG. 2, the first housing 2 includes an inner fitting portion 11 that is internally fitted into the bearing device 20, a first protruding portion 12 that is arranged in the first direction X1 from the inner fitting portion 11, and a first. It has a small-diameter tubular portion 13 arranged in the first direction X1 with respect to the protruding portion 12. The outer peripheral surface of the inner fitting portion 11 is a first fitting surface 11a into which the bearing device 20 is externally fitted. The outer diameter of the first protruding portion 12 is larger than the outer diameter of the inner fitting portion 11. Therefore, the first protruding portion 12 protrudes radially outward from the first fitting surface 11a of the inner fitting portion 11. The first protruding portion 12 has a first contact surface 12a that faces the second direction X2 and comes into contact with the inner ring 21a of the first bearing 21. The outer diameter of the small diameter tubular portion 13 is smaller than the outer diameter of the first protruding portion 12. Therefore, the outer peripheral surface of the small-diameter tubular portion 13 is recessed inward in the radial direction from the first protruding portion 12.

As shown in FIG. 1, the second housing 3 has a cylindrical shape and is arranged coaxially with the first housing 2. Between the first housing 2 and the second housing 3, there is an annular accommodation space S10 in which the rotor 40 and the stator 41 are accommodated. The base portion 4 has a ring shape and closes the second direction X2 of the accommodation space S10. The inner edge of the base portion 4 is tightened to a bolt B1 screwed into the first housing 2. The outer edge of the base portion 4 is tightened to a bolt B2 screwed into the second housing 3. As a result, the first housing 2, the second housing 3, and the base portion 4 are integrated. The first direction X1 of the accommodation space S10 is closed by the ring-shaped closing member 5. The closing member 5 is fastened to a bolt B3 at the end of the second housing 3 in the first direction X1. The second housing 3, the base portion 4, and the closing member 5 are provided with through holes 6 that continuously penetrate in a direction parallel to the axis X. A bolt B4 screwed into the base 101 is inserted into the through hole 6. Then, the housing 1 is tightened to the bolt B4 and fixed to the base 101.

The bearing device 20 is a two-row angular bearing, and includes a first bearing 21 and a second bearing 22 combined on the back surface. As shown in FIG. 2, the first bearing 21 includes an inner ring 21a, an outer ring 21b, and a ball 21c. The second bearing 22 includes an inner ring 22a, an outer ring 22b, and a ball 22c. Therefore, the first bearing 21 and the second bearing 22 do not have a seal for suppressing the leakage of grease. The inner rings 21a and 22a are fitted on the outer peripheral surface of the inner fitting portion 11. The inner rings 21a and 22a are sandwiched between the first protruding portion 12 and the base portion 4 of the first housing 2, and the preload by the fixed position preload is given by keeping the tightening amount by the bolt B1 constant. The first bearing 21 may be simply called a bearing. Further, although the bearing device 20 of the present disclosure is composed of two rows of bearings, it may be composed of a single row of bearings.

As shown in FIG. 1, the output shaft 30 is a cylindrical component. The output shaft 30 is arranged on the outer peripheral side of the first housing 2. As shown in FIG. 2, the output shaft 30 has an outer fitting portion 31 outerly fitted to the outer rings 21b and 22b, a second protruding portion 32 arranged in the first direction X1 of the outer fitting portion 31, and a second protrusion. A large-diameter tubular portion 33 arranged in the first direction X1 of the portion 32 is provided. The outer peripheral surface of the outer fitting portion 31 is a second fitting surface 31a into which the bearing device 20 is internally fitted. The inner diameter of the second protruding portion 32 is smaller than the inner diameter of the outer fitting portion 31. Therefore, the second protruding portion 32 protrudes radially inward from the second fitting surface 31a of the outer fitting portion 31. The second protruding portion 32 has a second contact surface 32a that faces the second direction X2 and comes into contact with the outer ring 21b of the first bearing 21. Further, a fixing member 7 is fixed to the end of the output shaft 30 in the second direction X2 by a bolt B6. The second contact surface 32a of the second protruding portion 32 and the fixing member 7 sandwich the outer rings 21b and 22b. Therefore, the output shaft 30 is fixed to the bearing device 20 so as not to move in the direction parallel to the shaft X.

The inner diameter of the large-diameter tubular portion 33 is formed to be larger than the inner diameter of the second protruding portion 32. The large-diameter tubular portion 33 extends from the outer edge of the second protruding portion 32 in the first direction X1. As shown in FIG. 1, a bolt B5 for tightening the stage 102 is screwed to the end of the large-diameter tubular portion 33 in the first direction X1. As a result, the output shaft 30 and the stage 102 rotate about the shaft X.

As shown in FIG. 1, the rotor 40 includes an annular core fitted in the output shaft 30 and a plurality of permanent magnets (not shown) embedded in the core and arranged at equal intervals in the circumferential direction. .. The stator 41 includes a plurality of cores 42 arranged at equal intervals in the circumferential direction along the inner peripheral surface of the second housing 3, and a coil 43 in which strands are multiplely wound around each core 42. .. Wiring (not shown) for supplying electric power is connected to the coil 43. Then, when electric power is supplied to the coil 43 and a rotating magnetic field is generated from the coil 43, the rotor 40 is driven and the stage 102 rotates about the rotation axis AX.

The cover 50 is a closing member that is attached to the first housing 2 and covers between the first housing 2 and the output shaft 30. The cover 50 is a ring-shaped component having a hole 51 in the center. As shown in FIG. 2, the inner edge of the cover 50 is tightened to a bolt and fixed to the end of the small-diameter tubular portion 13 of the first housing 2. The cover 50 extends radially outward from the small diameter tubular portion 13. The outer edge 52 of the cover 50 is close to the inner peripheral surface 33a of the large-diameter tubular portion 33.

As shown in FIG. 1, the angle detection device 60 includes a sensor substrate 61 attached to the first protrusion 12 of the first housing 2 and a rotating body 62 attached to the second protrusion 32 of the output shaft 30. .. The sensor board 61 includes a magnetic sensor 63, a ring-shaped first board 64 that supports the magnetic sensor 63, and a wiring 65 that connects to the magnetic sensor 63. The magnetic sensor 63 detects a change in magnetism and detects the rotation angle of the rotor 40 based on the change in magnetism. The magnetic sensor is, for example, a Hall element, a magnetoresistive element that functions as a so-called MR (Magnet Resistive) sensor, or a sensor that detects the displacement of a magnetostrictive line. The wiring 65 passes through the through hole 8 that continuously penetrates the first substrate 64, the first housing 2, and the base portion 4 and the hole portion 101a of the base 101, and extends in the second direction X2 from the base 101. ing.

The rotating body 62 includes a ring-shaped magnetic ring 66 and a second substrate 67 that supports the magnetic ring 66. The magnetic ring 66 is a magnetized body in which north poles and south poles are alternately magnetized in the circumferential direction. The magnetic ring 66 and the magnetic sensor 63 are arranged so as to face each other in the axis X direction. With such an arrangement, the magnetic sensor 63 detects the rotation angle of the magnetic ring 66, that is, the output shaft 30 (rotor 40) by counting the number of magnetic changes between the north and south poles of the magnetic ring 66. do. Therefore, the angle detection device 60 is an axial type magnetic sensor. Further, the first substrate 64 and the second substrate 67 are made of a non-magnetic material and are not affected by the rotating magnetic field generated from the stator 41.

Next, the details of the first housing 2, the output shaft 30, and the angle detection device 60 will be described. As shown in FIG. 3, the outer peripheral surface 12b of the first protruding portion 12 of the first housing 2 and the inner peripheral surface 32b of the second protruding portion 32 of the output shaft 30 face each other in the radial direction. A gap S1 extending in the axis X direction is provided between the first protruding portion 12 and the second protruding portion 32. The gap S1 is continuous with the gap S0 between the inner ring 21a and the outer ring 21b in the first bearing 21. Therefore, the grease inside the first bearing 21 may flow into the gap S1 through the gap S0.

The inner peripheral surface 32b of the second protruding portion 32 is located radially inside the inner peripheral surface of the outer ring 21b of the first bearing 21. In other words, the second protruding portion 32 covers a part of the gap S0 between the inner ring 21a and the outer ring 21b. Therefore, the grease of the first bearing 21 is unlikely to flow out toward the gap S1.

The first protruding portion 12 has a first mounting surface 12c facing the first direction X1. The second protrusion 32 has an annular second mounting surface 32c that faces the first direction X1. The first mounting surface 12c is located in the first direction X1 by the distance R1 with respect to the second mounting surface 32c.

The second substrate 67 is fixed to the second mounting surface 32c by bolts B7 (see FIG. 1). The inner edge of the second substrate 67 is located radially inside the second mounting surface 32c. The second substrate 67 has a throttle portion 68 extending from the inner edge in the second direction X2. The drawing portion 68 has a cylindrical shape and is in contact with the inner peripheral surface 32b of the second protruding portion 32. Therefore, the radial width of the gap S1 is narrowed by the throttle portion 68. Therefore, the grease that has entered the gap S1 passes through the throttle portion 68 and is less likely to flow out in the first direction X1. In the present invention, the throttle portion 68 is not limited to the one that abuts on the inner peripheral surface 32b of the second protruding portion 32.

A magnetic ring 66 is fixed to the surface of the second substrate 67 facing the first direction X1 with an adhesive. The magnetic ring 66 is arranged on the inner edge of the second substrate 67. The inner diameter of the magnetic ring 66 is smaller than the inner diameter of the second protrusion 32. Therefore, the inner edge of the magnetic ring 66 projects radially inward from the second protruding portion 32. The magnetic ring 66 is radially opposed to the outer peripheral surface 12b of the first protruding portion 12. The magnetic ring 66 and the outer peripheral surface 12b of the first protruding portion 12 are close to each other. Therefore, it is difficult for grease to pass between the magnetic ring 66 and the first protruding portion 12.

The first substrate 64 is fixed to the first mounting surface 12c by bolts B8 (see FIG. 1). The first substrate 64 extends radially outward from the first protruding portion 12. The first substrate 64 faces the second substrate 67 in the axis X direction. The magnetic sensor 63 is attached to the first substrate 64 so as to face the magnetic ring 66 in the axis X direction. From the above, an annular gap S2 extending in the radial direction is provided between the first substrate 64 and the second substrate.

Further, the step (distance R1) between the first mounting surface 12c and the second mounting surface 32c is designed so that the width of the gap S2 in the axis X direction becomes smaller. Therefore, the grease flowing out from the gap S1 to the gap S2 is difficult to move outward in the radial direction through the gap S2.

In the radial type magnetic sensor, the sensor substrate and the rotating body face each other in the radial direction. Therefore, the gap between the sensor substrate and the rotating body extends in the axis X direction. Then, the gap of the radial type magnetic sensor has the same length as the length in the axis X direction occupied by the radial type magnetic sensor. On the other hand, the length in the axis X direction occupied by the angle detection device 60 of the present embodiment is L1. The radial length L2 of the gap S2 is longer than the length L1. That is, according to the angle detection device 60 of the present embodiment, the path (gap S2) through which the grease flows out is longer than the length L1 in the axis X direction occupied by the angle detection device 60. Therefore, the gap S2 is longer than the case where it extends in the axial direction as in the case of the radial type magnetic sensor, and it is difficult for grease to pass through.

A gap S3 is provided between the outer edge 64a of the first substrate 64 and the inner peripheral surface 33a of the large-diameter tubular portion 33. The outer edge 64a of the first substrate 64 is close to the inner peripheral surface 33a of the large-diameter tubular portion 33. Therefore, the radial width of the gap S3 is very narrow, making it difficult for grease to pass through.

The outer edge 52 of the cover 50 is close to the inner peripheral surface 33a of the large-diameter tubular portion 33. A gap S4 (see FIG. 3) is provided between the outer edge 52 of the cover 50 and the inner peripheral surface 33a of the large-diameter tubular portion 33. The gap S4 has a narrow radial width. Therefore, the grease is unlikely to pass through the gap S4 and be discharged to the outside.

From the above, since the gaps S0 of the first bearing 21 and the gaps S1, S2, S3, and S4 communicating with the outside of the direct drive motor 100 form crank-shaped gap spaces, it is difficult for grease to pass through, and grease is difficult to pass through. Is hard to be discharged. Further, since the magnetic sensor 63 and the magnetic ring 66 have a labyrinth structure in close proximity to each other, it is difficult for grease to pass through and it is difficult for grease to be discharged.

As described above, the direct drive motor 100 of the first embodiment includes a housing 1 having a second housing 3 surrounding the outer periphery of the first housing 2 and the first housing 2, a bearing in which an inner ring 21a is externally fitted to the first housing 2. Detects the rotation angle of the tubular output shaft 30 outerly fitted to the outer ring 21b of the bearing, the rotor 40 outerly fitted to the output shaft 30, the stator 41 internally fitted to the second housing 3, and the output shaft 30. An angle detection device 60 for housing is provided. The first housing 2 has a first fitting surface 11a on which the inner ring 21a is fitted, and a first protruding portion 12 that protrudes radially outward from the first fitting surface 11a and abuts on the end surface of the inner ring 21a. Have. The output shaft 30 has a second fitting surface 31a into which the outer ring 21b is internally fitted, a second protruding portion 32 that projects radially inward from the second fitting surface 31a and abuts on the end surface of the outer ring, and an inner diameter of the second. 2 It has a large-diameter tubular portion 33 which is formed to have a diameter larger than the inner diameter of the protruding portion 32 and extends in the direction opposite to the outer ring 21b. The first protruding portion 12 has a first contact surface 12a that comes into contact with the inner ring 21a and a first mounting surface 12c that is located on the opposite side of the first contact surface 12a. The second protruding portion 32 is located on the side opposite to the second contact surface 32a that comes into contact with the outer ring 21b and the second contact surface 32a, and is located closer to the bearing than the first mounting surface 12c. It has a mounting surface 32c. The angle detection device 60 has a magnetic sensor 63, a ring-shaped sensor substrate 61 that is attached to the first attachment surface 12c and covers the second attachment surface 32c, and a permanent magnet, and is attached to the second attachment surface 32c. It has a ring-shaped rotating body 62 that faces the sensor substrate 61. The outer edge 64a of the sensor substrate 61 is close to the inner peripheral surface 33a of the large-diameter tubular portion 33.

The gap S2 between the sensor substrate 61 and the rotating body 62 extends in the radial direction and is longer than the case where it extends in the axis X direction. The gap S3 between the outer edge 64s of the sensor substrate 61 and the large diameter tubular portion 33 is small. Therefore, it is difficult for the grease to pass through the gaps S2 and S3, and it is difficult for the grease to flow out to the outside of the direct drive motor 100. Further, the gaps S2 and S3 are made by the first housing 2, the output shaft 30, and the angle detection device 60, and new parts are not used. Therefore, the increase in the number of parts can be suppressed. Further, it is possible to avoid increasing the size of the direct drive motor 100 in the axial direction.

The direct drive motor 100 of the first embodiment has a ring-shaped first spacer 71 interposed between the first attachment surface 12c and the sensor substrate 61, and a ring interposed between the second attachment surface 32c and the rotating body 62. A second spacer 72 in the shape of a shape is provided.

The rotating body 62 of the direct drive motor 100 of the first embodiment has a cylindrical throttle portion 68 that enters between the first protruding portion 12 and the second protruding portion 32 from the inner edge.

The width of the gap S1 between the first protruding portion 12 and the second protruding portion 32 in the radial direction is narrowed by the drawing portion 68, and it is difficult for grease to pass therethrough. Therefore, the possibility that grease is discharged to the outside of the direct drive motor 100 is further reduced.

The first housing 2 of the direct drive motor 100 of the first embodiment includes a small-diameter tubular portion 13 extending from the inner edge of the first protruding portion 12 in the direction opposite to the bearing. A cover 50 is provided which is attached to the end surface of the small-diameter tubular portion 13 and extends outward in the radial direction, and the outer edge 52 is close to the inner peripheral surface of the large-diameter tubular portion 33.

Even after passing through the gap S3 between the outer edge of the sensor substrate 61 and the large-diameter tubular portion 33, the sensor substrate 61 must pass through the gap S4 between the cover 50 and the large-diameter tubular portion 33 before being discharged to the outside. Therefore, the possibility that grease is discharged to the outside of the direct drive motor 100 is further reduced.

(Embodiment 2)
Next, the direct drive motor 100A according to the second embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic cross-sectional view showing a main configuration of the direct drive motor of the second embodiment. FIG. 5 is an enlarged view of the vicinity of the first protruding portion of FIG.

The direct drive motor 100A of the second embodiment is different from the direct drive motor 100 of the first embodiment in that the housing 1 is provided with the intake hole 80. Hereinafter, the differences will be focused on.

The intake hole 80 is a hole formed by continuously penetrating the first housing 2 and the base portion 4. The intake hole 80 has a first hole portion 81 extending in the axial X direction and a second hole portion 82 extending in the radial direction. The first hole portion 81 penetrates the first housing 2 and the base portion 4 in the axial direction. The first hole portion 81 is provided with a suction port 81a on the surface of the base portion 4 facing the second direction X2. A suction device 110 is connected to the suction port 81a.

As shown in FIG. 5, the second hole 82 is provided inside the first protrusion 12 of the first housing 2. An opening 83 of the second hole 82 is provided on the outer peripheral surface 12b of the first protrusion 12. Therefore, the opening 83 faces the inner peripheral surface 32b of the second protruding portion 32 and the throttle portion 68 in the radial direction, and is continuous with the gap S1. Further, the opening 83 extends in the circumferential direction along the outer peripheral surface 12b of the first protruding portion 12, and has an annular shape.

As described above, in the direct drive motor 100A of the second embodiment, the first housing 2 has an intake hole 80 that is sucked by the suction device 110. An opening 83 of the intake hole 80 is provided on the outer peripheral surface 12b of the first protruding portion 12. The opening 83 extends in the circumferential direction along the outer peripheral surface 12b of the first protruding portion 12.

According to the second embodiment, the intake hole 80 is depressurized by driving the suction device 110. Then, the grease flowing out into the gap S1 continuous with the opening 83 is sucked into the intake hole 80 and sucked into the suction device 110. Therefore, the possibility that grease is discharged to the outside of the direct drive motor 100 is further reduced.

100 Direct drive motor 1 Housing 2 1st housing 3 2nd housing 4 Base part 11 Inner fitting part 12 1st protruding part 12c 1st mounting surface 13 Small diameter cylinder part 20 Bearing device 21 1st bearing (bearing)
22 2nd bearing 21a, 22a Inner ring 21b, 22b Outer ring 30 Output shaft 31 Outer fitting part 32 2nd protruding part 32c 2nd mounting surface 33 Large diameter cylinder part 40 Rotor 41 stator 50 cover 60 Angle detection device 61 Sensor board 62 Rotating body 63 Magnetic sensor 64 1st board 66 Magnetic ring 67 2nd board 68 Aperture part 71 1st spacer 72 2nd spacer 80 Intake hole 81 1st hole 82 2nd hole 83 Opening S1, S2, S3, S4 Gap

Claims (5)

A housing having a first housing and a second housing surrounding the outer periphery of the first housing,
A bearing whose inner ring is externally fitted to the first housing,
A cylindrical output shaft fitted to the outer ring of the bearing and
The rotor fitted to the output shaft and
The stator fitted in the second housing and
An angle detection device that detects the rotation angle of the output shaft,
With
The first housing is
The first fitting surface on which the inner ring is externally fitted and
A first projecting portion that projects radially outward from the first fitting surface and abuts on the end surface of the inner ring,
Have,
The output shaft is
The second fitting surface into which the outer ring is internally fitted and
A second protruding portion that projects radially inward from the second fitting surface and abuts on the end surface of the outer ring,
A large-diameter tubular portion having an inner diameter larger than the inner diameter of the second protruding portion and extending in the direction opposite to the outer ring.
Have,
The first protrusion is
The first contact surface that comes into contact with the inner ring,
It has a first mounting surface located on the opposite side of the first contact surface.
The second protrusion is
A second contact surface that comes into contact with the outer ring,
It has a second mounting surface that is located on the opposite side of the second contact surface and is located closer to the bearing than the first mounting surface.
The angle detection device is
A ring-shaped sensor substrate having a magnetic sensor, which is attached to the first mounting surface and covers the second mounting surface,
A ring-shaped rotating body having a permanent magnet and attached to the second mounting surface and facing the sensor substrate.
Have,
A direct drive motor in which the outer edge of the sensor substrate is close to the inner peripheral surface of the large-diameter cylinder portion. A ring-shaped first spacer interposed between the first mounting surface and the sensor substrate,
A ring-shaped second spacer interposed between the second mounting surface and the rotating body,
The direct drive motor according to claim 1. The direct drive motor according to claim 1 or 2, wherein the rotating body has a cylindrical throttle portion that enters between the first protruding portion and the second protruding portion from the inner edge. The first housing includes a small-diameter tubular portion extending from the inner edge of the first protruding portion in a direction opposite to the bearing.
The direct drive according to any one of claims 1 to 3, further comprising a cover attached to the end surface of the small-diameter tubular portion, extending outward in the radial direction, and having an outer edge close to the inner peripheral surface of the large-diameter tubular portion. motor. The first housing has an intake hole that is sucked by a suction device.
An opening of the intake hole is provided on the outer peripheral surface of the first protrusion.
The direct drive motor according to any one of claims 1 to 4, wherein the opening extends in the circumferential direction along the outer peripheral surface of the first protruding portion.

Images