JP2811750B2 - Rotary drive motor seal structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention effectively prevents grease from leaking from bearings during rotation of a rotary drive motor, and thus reduces performance due to grease contamination of a rotating member such as an optical component. The present invention relates to an improvement in a seal structure of a rotary drive motor that avoids the above problem.

[Prior art] Generally, an optical scanning unit (hereinafter referred to as ROS [Raster Output Scaner]) used in a laser printer or the like.
As shown in FIG. 10, for example, a light source (not shown) provided in the unit case 1 and a beam from the light source
The polygon mirror 2 deflects the beam Bm over a predetermined scanning range by reflecting Bm on the reflecting surface 2a during the rotation operation, a polygon motor 3 for rotating the polygon mirror 2, and a polygon mirror 2. Is corrected so that the beam Bm is guided to a photoconductor (not shown) at an even pixel interval.
Lens 4. An opening 5 is formed in the unit case 1 corresponding to the optical path, and a seal glass 6 is attached to the opening 5.

A conventional polygon motor used in such ROS is disclosed in Japanese Utility Model Laid-Open No. 59-123824.

For example, as shown in FIG. 11, a cylindrical outer housing 201 fixed to the unit case 1 and a polygon mirror 2 rotatably fitted into the outer housing 201 via a pair of upper and lower bearings 202 are provided. The vehicle includes an inner rotor 203 for support, and a rotational force generating means 206 for applying a rotational force to the inner rotor 203.

And in this prior example, the inner rotor 203 is
A rotary plate 205 for mounting the polygon mirror 2 is mounted on the upper part of the rotary shaft 204. Also,
The rotating force generating means 206 mounts an appropriate number of magnets 208 on a flange 207 bent downward at the periphery of the rotating plate 205, and arranges a stator 209 on a peripheral wall of the outer housing 201 facing the magnet 208. By being wound around the stator 209 and energizing the coil 210,
The rotational force generated by the interaction between the stator 209 and the magnet 208 is applied to the inner rotor 203.

According to this type, even if the grease G injected into the bearing 202 tends to scatter as indicated by an arrow with the rotation of the inner rotor 203, the rotation plate 205
Block the upper region of the bearing 202 support,
The rotating plate 205 functions as a seal member for preventing the grease G from scattering. The grease G does not go directly to the polygon mirror 2, and the reflection surface 2 a of the polygon mirror 2 is hardly stained by the grease G. ing.

[Problems to be Solved by the Invention] In such a conventional polygon motor seal structure, the situation in which the grease G from the bearing 202 goes directly to the polygon mirror 2 is effectively prevented by the rotating plate 205. However, it was not possible to positively prevent the grease G wrapping around the rotary plate 205 from the bearing 202 and scattered to the outside, and was insufficient as a means for preventing the grease G from leaking from the bearing 202. .

As means for solving such a problem, the inner rotor 203 or the rotating plate 205 and the outer housing
Although it is necessary to positively seal the gap between the polygon motor 201 and the unit case 1, considering the stability of the rotation operation of the polygon motor 3, low cost, and handling,
As the seal structure, the gap cannot be directly closed by a seal member, and a non-contact type seal structure must be employed.

Under such conditions, as the non-contact type seal structure, a labyrinth seal is applied to the gap portion,
It is conceivable to attenuate the airflow from the bearing 202 to the outside.

However, even if such a labyrinth seal is adopted, the labyrinth seal itself cannot completely prevent the air flow from leaking from the gap, and therefore, in the case of an inner rotor type motor, it is desirable to further improve the sealing performance. A technical problem arises.

Further, in recent years, from the viewpoint of improving the rotation stability and assemblability of the rotor, in addition to the inner rotor type motor, an outer rotor type motor that is rotatably supported on an inner fixed shaft via a bearing has been provided. .

In this outer rotor type motor, seals must be applied to the upper and lower portions of the bearing support portion due to the specificity of the configuration, but a labyrinth seal is applied to the upper and lower portions similarly to the inner rotor type motor. In this case, the airflow going down the bearing support should be attenuated to some extent by a labyrinth seal,
The grease scattered by the damped airflow adheres to the bottom wall of the unit case, so the grease scatter is not a problem.However, the inner space between the bearing support and the polygon mirror fixed to the outer rotor is low. Since a rotating plate such as that used in a rotor type motor cannot be arranged, even if airflow heading upstream of the bearing support is attenuated to some extent by the labyrinth seal, airflow from this labyrinth seal can be reduced. The grease discharged along with this is likely to adhere to the polygon mirror, and there arises a technical problem that it is desired to further improve the sealing performance of the outer rotor type motor.

SUMMARY OF THE INVENTION The present invention has been made to solve the above technical problem, and is intended to improve the sealing performance of grease leakage from bearings of inner rotor type and outer rotor type motors, and to improve the sealing performance of a rotary drive motor. Provides structure.

[Means for Solving the Problems] That is, a first aspect of the present invention is a cylindrical outer housing fixedly provided on a mounting base, and a rotatable body rotatably inserted into the outer housing via a bearing. Assuming a rotary drive motor including a supporting inner rotor and a rotational force generating means for applying a rotational force to the inner rotor, at least a part of a portion located outside a bearing support of the inner rotor and an outer housing or A minute gap is formed between the mounting base and the mounting base, and an airflow generating section for generating a forced airflow toward the bearing support portion with the rotation of the inner rotor is formed on a wall defining the minute gap. It is a seal structure of a rotary drive motor.

According to a second aspect of the present invention, an inner fixed shaft fixedly provided on a mounting base, and a tubular shape formed to be loosely fitted to the inner fixed shaft, and rotatable around the inner fixed shaft via a bearing. Assuming a rotary drive motor including an outer rotor for supporting a rotating body to be mounted and a rotational force generating means for applying a rotational force to the outer rotor, a release portion of the outer rotor is provided outside the bearing support portion of the outer rotor. A minute gap is formed between at least a part of the portion located on the opposite side and the inner fixing shaft or the mounting base, and a wall defining the minute gap is formed on the outer side of the bearing support portion with the rotation of the outer rotor. While forming an air seal portion for preventing airflow toward the outer rotor, the release portion of the outer rotor is closed with a cover that is not in contact with the bearing. A seal structure of a rotary drive motor, characterized in that the.

In such technical means, the scope of the present invention covers both the inner rotor type and the outer rotor type motors. In particular, optical components such as polygon mirrors and hologram disks are used as rotating objects. It is effective when you do.

Further, as the outer housing or the inner fixing shaft, a separate member may be attached to the attachment base, or may be formed integrally with the attachment base. Further, the configuration, the number of used bearings, and the support structure of the bearing can be appropriately selected as long as the bearing can rotate and support the rotor. Furthermore, in the present invention, it is assumed that the inner rotor or the outer rotor includes a member that rotates integrally with the rotating shaft. The design of the torque generating means can be changed as appropriate as long as the torque is applied to the rotor.

Further, the minute gap formed between the inner rotor or the outer rotor and the fixing member may be appropriately set within a range in which the function of the airflow generation unit or the air seal unit can be sufficiently exhibited in consideration of manufacturing errors and mounting errors of parts. The dimensional relationship is selected.

In addition, as for the location where the airflow generating section and the air seal section are formed, it is possible to select either the rotor side, the fixed member side, or both as long as the respective functions can be exhibited. The air seal portion only needs to block airflow from the bearing support portion side when the rotor rotates, and includes a seal configuration for suppressing airflow release such as a labyrinth seal for attenuating the airflow, and includes a bearing support portion. It also includes an airflow generation unit that sends a forced airflow to the side. In this case, as long as the airflow generating portion can generate an airflow toward the bearing support portion with the rotation of the rotor, a continuous or discontinuous groove extending in the spiral direction can be formed, or the airflow generating portion can be formed. The design can be changed as appropriate, such as by forming a fin portion for use, but a continuous or discontinuous groove configuration extending in the spiral direction is preferable from the viewpoint of airflow generation efficiency and cost.

[Operation] According to the first invention described above, in the inner rotor type rotary drive motor, a minute gap is formed between a part of the inner rotor located on the outer side of the bearing support and a fixing member such as the outer housing. An airflow generation unit is formed on the wall defining the minute gap, and the forced airflow generated from the airflow generation unit when the inner rotor rotates is directed toward the bearing support.

Further, according to the second invention, in the outer rotor-type rotary drive motor, a minute gap is formed between a part of the outer rotor located on the outer side of the bearing support and opposite to the release section and a fixed member such as an inner shaft. A gap is formed, and an air seal portion is formed in a wall portion defining the minute gap, so that the air flow heading outward from the bearing support portion during rotation of the outer rotor is effectively blocked by the air seal portion. on the other hand,
Since the release portion of the outer rotor is closed by a cover that is not in contact with the bearing, the grease discharged from the bearing is blocked by the cover without impairing the stability of the rotational operation of the outer rotor.

Hereinafter, the present invention will be described in detail based on an embodiment shown in the accompanying drawings.

Embodiment 1 FIG. 1 shows an inner rotor type motor 3 for driving a ROS polygon mirror 2, and its basic configuration is a cylindrical outer housing 10 fixed to a motor mounting hole of a unit case 1, An inner rotor 3 rotatably inserted into the outer housing 10 via a pair of bearings 21 and 22.
0, and a rotational force generating means 40 for applying a rotational force to the inner rotor 30.

In this embodiment, the outer housing 10 includes a cylindrical portion 11 and a flange-like mounting base 12 extending in a horizontal direction around substantially the center of the cylindrical portion 11, and an inner peripheral wall of the cylindrical portion 11. Housing steps 13, 14 for housing the bearings 21, 22 are integrally formed in the upper and lower parts.

The inner rotor 30 includes a rotating shaft 31 and a polygon mirror 2 press-fitted on the upper portion of the rotating shaft 31.
And a donut-shaped rotor yoke 33 press-fitted into the lower portion of the rotary shaft 31. And the rotating shaft
Vertical positioning projections 34 of the rotor hub 32 and the upper bearing 21 are formed at the upper part of the upper part 31, and vertical positioning projections 35 of the lower bearing 22 are formed at the center of the rotor yoke 33. I have. and again,
A weight mounting groove 36 is recessed around the bottom surfaces of the rotor hub 32 and the rotor yoke 33.
A balance weight 37 is attached at an appropriate position of the rotor hub 32 to stabilize the rotation operation of the rotor hub 32 and the rotor yoke 33.

Further, the bearings 21 and 22 are provided with bushes 2 on the outside thereof.
The rotating shaft 31 and the accommodation step 13,1 of the cylindrical section 11 via 3,24
It is fitted in the gap with 4. At this time, the upper end of the upper bearing 21 is brought into contact with the positioning projection 34,
The lower end portion is positioned in the up-down direction by abutting the bottom surface of the upper housing step portion 13. On the other hand, the upper end of the lower bearing 22 is urged by a coil spring 25, and the lower end thereof is brought into contact with the positioning projection 35 to be positioned vertically. Reference numeral 26 denotes a side pressure spring for preventing the bearing 22 from creeping and preventing the rotating shaft 31 from falling down.

Further, the rotational force generating means 40 is provided with the rotor yoke 33
A rising flange 41 is formed on the peripheral edge of the outer housing 10, and a magnet 42 is fixed to the rising flange 41, and a stator 43 on which a coil 44 is wound is disposed on the cylindrical portion 11 of the outer housing 10 facing the magnet 42. When the coil 44 is energized, a rotating force is generated between the stator 43 and the magnet 42, and the entire inner rotor 30 is rotated through the rotor yoke 33.

Reference numeral 51 denotes a motor control printed circuit board that is screwed to the mounting base 12 of the outer housing 10, and 53 denotes a rubber cushion 54 on the mounting base 12 of the outer housing 10.
A rotor cover 56 is fixed by screws 55 to cover the inner rotor 30 from outside, and 56 is a holder for the polygon mirror 2 which is screwed to the top of the rotating shaft 31 by screws 57.

In this embodiment, the bottom surface of the rotor hub 32 located above the upper bearing 21 and the top surface of the cylindrical portion 11 and the bush 13 of the outer housing 10, as shown in FIGS. A labyrinth seal 71 is formed in the minute gap 70 between them. In this embodiment, the labyrinth seal 71 has a ring-shaped recess 72 formed on the outer housing 10 side and a ring-shaped projection 73 loosely fitted in the recess 72 on the rotor hub 32 side. Narrow gaps 74, wide gaps 75, and narrow gaps 76 are alternately formed.

Further, a projection which is a defining wall portion of the minute gap 76
A helical groove 60 is formed on the outer peripheral surface of 73 so as to extend in a direction (lower side in the figure) leading to the upper bearing 21 with respect to a reverse rotation direction of the inner rotor 30 (m is a rotation direction of the inner rotor 30 in FIG. 2). Have been.

Therefore, according to this embodiment, when the inner rotor 30 rotates in a predetermined direction, the grease G
Attempts to scatter with the airflow A going outward in the radial direction.

At this time, since the labyrinth seal 71 is formed in the gap portion 70, even if the airflow A is discharged to the labyrinth seal 71 side, the airflow A remains in the labyrinth seal 71.
It gradually decreases at 71.

On the other hand, as the rotor hub 32 rotates, a forced airflow S is generated from the spiral groove 60 toward the lower side, and the damped airflow A
Grease G, which has been moving on board, is contained. For this reason, the grease G never goes to the outside from the gap 70 between the outer housing 10 and the rotor hub 32, and the grease G from the upper bearing 21 scatters outside and adheres to the polygon mirror 2 completely. To be avoided.

The grease G also scatters from the lower bearing 22, but the scattered grease G is confined in a closed space between the rotor cover 53 and the outer housing 10, and is not discharged to the outside.

In evaluating the sealing performance in this example, the polygon mirror 2 was rotated at 12000 rpm while the labyrinth seal 71 and the spiral groove 60 were not used as a comparative example, and the motor was surrounded by a transparent film sheet. In the comparative example, the grease was scattered after about one hour. However, in the example, the grease was not scattered even after about one week.

In this embodiment, a seal configuration using the spiral groove 60 in addition to the labyrinth seal 71 is employed. However, a seal configuration using only the spiral groove 60 without using the labyrinth seal 71 may be used.

Second Embodiment FIG. 4 shows an embodiment in which the present invention is applied to an inner rotor type motor different from the first embodiment.

The basic configuration of the motor 3 according to this embodiment is substantially the same as that of the first embodiment. However, unlike the first embodiment, the outer housing 10 shares the ROS unit case 1 itself. Is a rotating shaft 31,
Rotor yoke attached to the upper part of this rotating shaft 31
The rotor yoke 38 functions as a mount for the polygon mirror 2 and has a rotational force generating means 40.
Function as a mounting member for the magnet 42 of FIG. Further, a stator 43 on which a coil 44 is wound is provided in the outer housing 10 facing the magnet 42, and the top flange 31 a of the rotating shaft 31 serves as a holder for the polygon mirror 2.

In this embodiment, a ring-shaped protrusion 77 having an inverted trapezoidal cross section is formed on the bottom surface of the rotor yoke 38, and a minute gap is formed between the inner peripheral surface of the protrusion 77 and the outer housing 10.
In addition to the space 78, a spiral groove 60 is formed on the inner peripheral surface of the projection 77 in a direction leading to the upper bearing 21 with respect to the reverse rotation direction of the inner rotor 30.

In FIG. 4, reference numerals 27 and 28 denote upper and lower bearings 2.
Reference numerals 1 and 22 denote retaining members. Reference numeral 29 denotes a holding spring that urges the upper and lower bearings 21 and 22 in a direction away from each other. Components similar to those of the first embodiment are denoted by the same reference numerals as those of the first embodiment. Here, the detailed description is omitted.

Therefore, according to this embodiment, when the inner rotor 30 rotates, the grease that the forced airflow S generated by the spiral groove 60 tends to scatter from the upper bearing 21 is securely contained as in the first embodiment.

Embodiment 3 FIG. 5 shows an embodiment in which the present invention is applied to a ROS outer rotor type motor. The basic structure of the motor 3 is an inner fixed shaft 80 which is fixedly provided to the ROS unit case 1. An outer rotor 100 rotatably supported on the inner fixed shaft 80 via a pair of upper and lower bearings 91 and 92, and a rotational force generating means 110 for applying a rotational force to the outer rotor 100.

In this embodiment, the inner fixing shaft 80 is fixed to the mounting portion 1a of the unit case 1 with a screw 81.

Further, the outer rotor 100 has a cylindrical portion 1 in which a protruding flange portion 102 protruding outwardly is formed integrally with a top peripheral edge.
01 and a retaining ring 1
And a donut-shaped rotor yoke 103 positioned at 04. On the inner peripheral wall of the cylindrical portion 101, housing steps 105 and 106 for housing the bearings 91 and 92 are formed. On the other hand, a weight mounting groove 107 is formed around the upper surface of the rotor yoke 103.
A balance weight 108 is attached to an appropriate position of the rotor yoke to stabilize the rotation operation of the rotor yoke 103.

Further, the upper bearing 91 has a lower surface portion abutting against a bottom portion of the upper accommodation step portion 105, and the inner fixed shaft 8
Positioning is performed by urging the upper surface with a preload spring 94 locked to a stop ring 93 at zero. On the other hand, a positioning projection 95 of the lower bearing 92 is formed on the mounting portion 1a. The lower bearing 92 has its lower surface abutting on the positioning projection 95, and its upper surface is accommodated by the accommodation step 106.
And is positioned in contact with the top of the.

Further, the rotating force generating means 110 fixes the magnet 111 around the lower surface of the rotor yoke 103, and arranges a stator 112 around which a coil 113 is wound in the unit case 1 facing the magnet 111. Yoke 114 made of iron, ferrous metal or ferrite
Is provided, and the coil 113 is energized to generate a rotating action force between the stator 112 and the magnet 111, thereby rotating the entire outer rotor 100 through the rotor yoke 103.

The polygon mirror 2 has its upper surface in contact with the protruding flange portion 102 and pushes the lower surface thereof up with a spring 120.
And is held by the outer rotor 100.

Further, in this embodiment, as shown in FIGS. 5 and 6, a labyrinth seal 131 is provided in a gap 130 between the bottom of the cylindrical portion 101 of the outer rotor 100 and the unit case 1.
Are formed. The labyrinth seal 131 forms a ring-shaped recess 132 on the unit case 1 side, and also forms a ring-shaped protrusion 133 on the cylindrical portion 101 side for loose fitting in the recess 132, and a narrow gap 134, Wide gap 135, narrow gap 13
6 are arranged alternately.

The release portion of the cylindrical portion 101 of the outer rotor 100 is closed by a cover 140 that is not in contact with the upper bearing 91.

Therefore, according to the seal structure of the rotary drive motor according to this embodiment, when the outer rotor 100 rotates, the grease G tends to scatter from the bearings 91 and 92, but the grease G scattered from the upper bearing 91 is not The grease G from the upper bearing 91 is not blocked by the cover 140 and scattered outside, so that the polygon mirror 2 is not stained.

On the other hand, in the gap portion communicating with the lower bearing 91, an airflow directed outward is formed with the rotation of the outer rotor 100, and the grease G from the lower bearing 92 tends to be discharged to the outside by riding this airflow. Since the airflow gradually attenuates in the labyrinth seal 131, the grease G that has moved along with the airflow hardly passes through the labyrinth seal 131 and adheres to the wall surface. Although a very small portion of the grease G may pass through the labyrinth seal 131, the airflow passing through the labyrinth seal 131 is extremely weak, so the grease G that has passed with the airflow
There is almost no risk that the grease G will go around in the direction of the polygon mirror 2, and the grease G from the lower bearing 92 will be completely prevented from adhering to the polygon mirror 2.

In evaluating the sealing performance according to this embodiment, the polygon mirror 2 was rotated at 12000 rpm with the labyrinth seal 71 and the one without the spiral groove 60 as a comparative example, with the periphery of the motor surrounded by a transparent film sheet. However, in the comparative example, grease was scattered about 1 hour later, but in the example, the grease was dispersed about 10 hours later.
Slight grease scattering of about 1/10 was observed.

Embodiment 4 The basic structure of a motor 3 according to FIGS. 7 and 8 is substantially the same as that of Embodiment 3, but is different from Embodiment 3 in that a labyrinth seal formed in a gap portion communicating with the lower bearing 92 is provided. A spiral groove 150 for generating a forced airflow directed inward is formed in the minute gap 136 of 131. In this embodiment, the spiral groove 150 is formed in the cylindrical portion 10 of the outer rotor 100.
1 is formed on the lower peripheral edge, and the spiral direction thereof is set to be lower than the reverse rotation direction of the outer rotor 100. In FIG. 7, m indicates the rotation direction of the outer rotor 100.

Therefore, according to this embodiment, when the outer rotor 100 rotates, the same operation and effect as those of the third embodiment are obtained, but the forced airflow S accompanying the rotation of the spiral groove 150 is formed in the gap 130 communicating with the lower bearing 92. Is generated in the direction of the arrow, so that the grease G from the lower bearing 92 is securely sealed in the gap, and the sealing performance is further improved as compared with the third embodiment.

In evaluating the sealing performance according to this embodiment, the polygon mirror 2 was rotated at 12000 rpm with the labyrinth seal 71 and the one without the spiral groove 60 as a comparative example, with the periphery of the motor surrounded by a transparent film sheet. However, in the comparative example, grease was scattered about 1 hour later, but in the example, even after about one week,
No grease was scattered.

In this embodiment, the seal configuration using the spiral groove 150 in addition to the labyrinth seal 131 is adopted. However, a seal configuration using only the spiral groove 150 without using the labyrinth seal 131 may be used.

In the above embodiment, the outer rotor 100
A spiral groove 150 is formed on the lower peripheral edge of the cylindrical portion 101 of
However, the present invention is not limited to this. For example, as shown in FIG. 9, a spiral groove 160 having a reverse screw relationship with the spiral groove 150 is formed in a wall portion of the labyrinth seal 131 facing the cylindrical portion 101 in the gap portion 136. The same operation and effect as those of the embodiment can be obtained even if the above is formed.

[Effects of the Invention] As described above, according to the seal structure of the rotary drive motor according to the first aspect, in the inner rotor type motor, the bearing is formed when the inner rotor is rotated in the gap portion outward from the bearing support portion. Since the forced airflow directed to the support portion side is generated, even if grease tries to scatter from the bearing, the grease can be reliably contained by the forced airflow, and accordingly, the contamination of the rotating body due to the grease scattered. Can be more reliably prevented.

According to the seal structure of the rotary drive motor according to the second aspect, in the outer rotor type motor, the outer gap portion of the bearing support portion located on the opposite side to the release portion of the outer rotor is closed by the air seal, The release part of the outer rotor is closed by a cover that is not in contact with the bearing, so grease that scatters from the bearing is relatively hard to reach the rotating body, specifically grease that scatters toward the mounting base. Can be effectively prevented by an air seal, while grease that is relatively easy to reach the rotating body, specifically, grease that scatters toward the space can be reliably prevented by the cover. Dirt on the rotating body due to the scattering of water can be reliably prevented.

Further, according to the seal structure of the rotary drive motor according to the third aspect, in the outer rotor type motor, a forced airflow toward the bearing support portion side is generated in the gap portion on the mounting base side. Thus, it is possible to reliably prevent the airflow from leaking out, and accordingly, it is possible to further improve the sealing performance against the grease leakage.

Furthermore, according to the seal structure of the rotary drive motor according to the fourth aspect, it is possible to efficiently generate the forced airflow toward the bearing support portion in the gap to be sealed with a very simple configuration.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing a first embodiment in which the present invention is applied to an inner rotor type motor, FIG. 2 is an explanatory view showing a configuration of a rotor hub of an inner rotor used in the first embodiment, and FIG. FIG. 4 is an enlarged view of a part III in FIG. 4, FIG. 4 is a sectional explanatory view showing a second embodiment in which the present invention is applied to an inner rotor type motor, and FIG. 5 is a third embodiment in which the present invention is applied to an outer rotor type motor. FIG. 6 is an enlarged view of a portion VI in FIG. 4, FIG. 7 is a schematic diagram showing a fourth embodiment in which the present invention is applied to an outer rotor type motor, and FIG. 8 is a fifth embodiment of the fourth embodiment. 9 is an explanatory view corresponding to FIG. 7, FIG. 9 is an explanatory view corresponding to FIG. 7, showing a modification of the fourth embodiment, FIG. 10 is an explanatory view showing a schematic configuration of the ROS, and FIG. FIG. 3 is an explanatory sectional view showing an example of a rotary drive motor. [Description of Signs] 1 Unit case (mounting base) 2 Polygon mirror (rotated body) 3 Polygon motor (rotary drive motor) 10 Outer housing 21, 22 Bearing 30 Inner rotor 40 Rotating force generating means 60 Spiral groove (air flow generating part) 80 Inner fixed shaft 91, 92 Bearing 100 Outer rotor 131 Labyrinth seal (air seal part) 140 Cover 150 Spiral groove (Air seal part, air flow generation part) 160 ... spiral groove (air seal part, air flow generation part)

Claims (4)

(57) [Claims] A cylindrical outer housing fixed to a mounting base; an inner rotor rotatably fitted into the outer housing via a bearing via a bearing; and a rotational force applied to the inner rotor. A rotation gap between the outer housing or the mounting base and at least a part of a portion of the inner rotor located on the outer side of the bearing support portion. A seal structure for a rotary drive motor, wherein an airflow generation unit for generating a forced airflow directed toward a bearing support unit with the rotation of an inner rotor is formed in a wall defining a gap. 2. An inner fixed shaft fixedly provided on a mounting base, and a cylindrical shape for loosely fitting to the inner fixed shaft, which is rotatably mounted around the inner fixed shaft via a bearing. In a rotary drive motor comprising: an outer rotor for supporting a rotating body; and a rotational force generating means for applying a rotational force to the outer rotor, the rotary drive motor is located outside a bearing support portion of the outer rotor and opposite to a release portion of the outer rotor. A minute gap is formed between at least a part of the portion and the inner fixed shaft or the mounting base, and a wall for defining the minute gap is provided for preventing an air flow toward the outer side of the bearing support portion with the rotation of the outer rotor. While the air seal portion is formed, the release portion of the outer rotor is closed by a cover that is not in contact with the bearing. Seal structure of a rotary drive motor, wherein. 3. The seal structure of a rotary drive motor according to claim 2, wherein the air seal portion is an airflow generation portion for generating a forced airflow toward the bearing support portion as the outer rotor rotates. . 4. The rotation according to claim 1, wherein the airflow generating section is a continuous or discontinuous groove extending along a predetermined spiral direction with respect to the rotation direction of the inner rotor or the outer rotor. Drive motor seal structure.