WO2023223656A1

WO2023223656A1 - Actuator

Info

Publication number: WO2023223656A1
Application number: PCT/JP2023/010834
Authority: WO
Inventors: セバスチャンマーカート
Original assignee: 住友重機械工業株式会社
Priority date: 2022-05-18
Filing date: 2023-03-20
Publication date: 2023-11-23
Also published as: JP2023170203A

Abstract

An actuator provided with a rotating shaft 12 and a motor 14 for rotating the rotating shaft 12, wherein the motor 14 is provided with a rotor 62 disposed on the rotating shaft 12 and a first air passage 100 which is provided between the rotating shaft 12 and the rotor 62 and which causes a load-side space 90 on a load side and a counter-load-side space 92 on a counter load side with respect to the rotor 62 to communicate to and from each other and, as the rotating shaft 12 rotates, the air can be guided from the load-side space 90 to the counter-load-side space 92 through the first air passage 100.

Description

actuator

The present disclosure relates to an actuator.

Patent Document 1 discloses an actuator that includes a rotating shaft and a motor that rotates the rotating shaft.

JP2021-097430A

If the temperature of the internal parts of the motor (rotor, etc.) becomes excessively high, it will have a negative effect on the output of the actuator, so it is necessary to take measures to cool them. The inventor of the present application has discovered a new idea for cooling the internal parts of a motor.

One of the objectives of the present disclosure is to provide a technology that can cool internal parts of a motor.

An actuator of the present disclosure includes a rotating shaft and a motor that rotates the rotating shaft, and the motor includes a rotor disposed on the rotating shaft and a rotor provided between the rotating shaft and the rotor. a first air passage that communicates a load side space on the load side with respect to the rotor and an anti-load side space on the anti-load side with respect to the rotor, the first air passage Air can be guided from the load side space to the counter load side space through the first air passage.

According to the present disclosure, it becomes possible to cool the internal parts of the motor.

FIG. 3 is a side sectional view of the actuator of the first embodiment. FIG. 2 is an enlarged view of FIG. 1; FIG. 3 is a perspective view of the rotating shaft of the first embodiment. 2 is a sectional view taken along line AA in FIG. 1. FIG. FIG. 3 is an explanatory diagram of the operation of the actuator of the first embodiment. (A) is a diagram showing the results of fluid analysis, and (B) is another diagram showing the results of fluid analysis. FIG. 7 is an explanatory diagram of the operation of the actuator of the second embodiment. FIG. 5 is a cross-sectional view of the actuator of the third embodiment viewed from the same viewpoint as FIG. 4; It is a side sectional view showing a part of actuator of a 4th embodiment. It is a perspective view showing a fan of a 4th embodiment.

Embodiments will be described below. Identical components are given the same reference numerals and redundant explanations will be omitted. In each drawing, constituent elements are omitted, enlarged, or reduced as appropriate for convenience of explanation. The drawings should be viewed according to the direction of the symbols. Unless otherwise specified, "communication" as used herein includes not only the case where two parties directly satisfy the mentioned conditions, but also the case where the two parties satisfy the mentioned condition indirectly through another element.

(First Embodiment) Refer to FIG. 1. The actuator 10 includes a rotating shaft 12, a motor 14 that rotates the rotating shaft 12, a reducer 16 connected to the load side of the motor 14, and a load-side cover 18 that covers the reducer 16 from the load side. Hereinafter, the direction along the rotation center line C12 of the rotating shaft 12 will be referred to as the axial direction . Furthermore, in this specification, the load side refers to one side in the axial direction X (the left side in FIG. 1), and the anti-load side refers to the other side in the axial direction X (the right side in FIG. 1).

The actuator 10 is supported by a support member 20 located outside the actuator 10, and drives a driven member 22 located outside the actuator 10. A specific example of the driven member 22 is not particularly limited. The driven member 22 is, for example, a part of a driven machine such as a conveyor, a wheel, a machine tool, or a robot (industrial robot, service robot, etc.). The support member 20 of this embodiment is fixed to the reducer housing 28 of the reducer 16, and the driven member 22 is fixed to the load side cover 18. In addition to this, the support member 20 may be fixed to the load-side cover 18 and the driven member 22 may be fixed to the reducer housing 28.

The speed reducer 16 includes an input shaft 24 which also serves as the rotating shaft 12, a speed reducer mechanism 26 to which input rotation is transmitted from the input shaft 24, and a speed reducer housing 28 that houses the speed reducer mechanism 26.

The speed reduction mechanism 26 of this embodiment is a flexural mesh gear mechanism that includes an external gear 30 and

internal gears

32A and 32B that mesh with each other, one of which is a flexural gear (here, the external gear 30). When the input rotation is transmitted from the input shaft 24, the deceleration mechanism 26 flexibly deforms the flexural gear so as to change the meshing position with other gears in the rotational direction of the input shaft 24. The deceleration mechanism 26 rotates the external gear 30 and one of the

internal gears

32A and 32B (in this case, the external gear 30) by the flexural deformation of the flexural gear, and uses the rotational component as an output rotation to drive the driven member 22. Output to. The speed reduction mechanism 26 of this embodiment is a cylindrical flexible gear having a first internal gear 32A disposed on the anti-load side and a second internal gear 32B disposed on the load side as

internal gears

32A and 32B. It is a meshing gear mechanism. Since the principle of operation of this type of speed reduction mechanism 26 is well known, the explanation thereof will be omitted here. An example will be described in which the speed reduction mechanism 26 of this embodiment outputs output rotation to the driven member 22 via the load side cover 18. In addition to this, the output rotation may be output to the driven member 22 via the reducer housing 28 instead of the load side cover 18. A gear bearing 36 that rotatably supports the external gear 30 is arranged between the input shaft 24 and the external gear 30.

The reducer housing 28 of this embodiment includes a plurality of

housing members

28a and 28b that are integrated with each other. The plurality of

housing members

28a, 28b include a first housing member 28a that also serves as the first internal gear 32A, and a second housing member 28b that is disposed radially outward with respect to the second internal gear 32B. The reducer housing 28 is connected to the motor housing 66 of the motor 14 by bolts or the like. A main bearing 38 is arranged between the reducer housing 28 and the second internal gear 32B.

The load-side cover 18 covers the speed reduction mechanism 26 and the input shaft 24, which also serves as the rotating shaft 12, from the load side as part of the speed reducer 16. The load-side cover 18 functions as a synchronizing member that can synchronize with the rotation component of the external gear 30. The load side cover 18 has a cylindrical shape as a whole. The load-side cover 18 is overlapped with the first protrusion 32Ba that protrudes from the second internal gear 32B toward the load side, and is fixed to the second internal gear 32B using bolts (not shown) or the like. The load-side cover 18 includes a second protrusion 18a that protrudes toward the opposite load side and engages with the first protrusion 32Ba of the second internal gear 32B through a spigot. A load-side bearing 40 that rotatably supports a rotating shaft is arranged on the second protrusion 18a of the load-side cover 18.

The actuator 10 includes a pipe member 42 disposed within a hollow portion 12a (described later) of the rotating shaft 12. The pipe member 42 passes through the hollow portion 12a of the rotating shaft 12 in the axial direction X. The load side portion of the pipe member 42 is fixed to the load side cover 18 and is provided so as to be rotatable integrally with the load side cover 18. The load side portion of the pipe member 42 of this embodiment is fixed to the load side cover 18 by tightly fitting into the through hole 18b formed in the load side cover 18. This fixing mode is not particularly limited, and bolts or the like may be used. The anti-load side portion of the pipe member 42 is rotatably supported by the rotating shaft 12 via an internal bearing 44 disposed between the pipe member 42 and the rotating shaft 12.

The actuator 10 includes a first rotation detector 46A that detects the rotation of the rotating shaft 12 and a second rotation detector 46B that detects the rotation of the pipe member 42. The first rotation detector 46A includes a first detected part 46Aa that is provided to be rotatable integrally with the rotating shaft 12, and a first detection part 46Ab that faces the first detected part 46Aa. The second rotation detector 46B includes a second detected part 46Ba that is provided to be rotatable integrally with the pipe member 42, and a second detection part 46Bb that faces the second detected part 46Ba. The detected parts 46Aa and 46Ba are, for example, scales such as optical scales and magnetic scales. The detection units 46Ab and 46Bb are, for example, sensors such as optical sensors and magnetic sensors. The detection units 46Ab and 46Bb can detect the rotation of the rotating body (rotation shaft 12, pipe member 42) by detecting changes in predetermined physical quantities (light amount, magnetic field, etc.) accompanying the rotation of the detected units 46Aa and 46Ba. be. The first detection section 46Ab and the second detection section 46Bb are mounted on a common sensor board 48. Sensor board 48 is attached to a mount 50 that is secured to motor housing 66. A driver board 52 equipped with a driver IC (not shown) used to control the motor 14 is attached to the mount 50 .

Please refer to FIGS. 2 and 3. In the rotating shaft 12 of this embodiment, a rotor shaft 60 on which a rotor 62 of a motor 14 is arranged and an input shaft 24 of a reducer 16 to which rotation of the rotor shaft 60 is input are integrated. In the rotating shaft 12 of this embodiment, the rotor shaft 60 and the input shaft 24 are made of the same member. In addition to this, the rotor shaft 60 and the input shaft 24 of the rotating shaft 12 may be constructed from different members.

The rotating shaft 12 includes a hollow portion 12a that penetrates the rotating shaft 12 in the axial direction A flange portion 12d provided at the opposite end of the load side. The rotor arrangement portion 12b is provided on the outer circumference of the rotating shaft 12. The rotor 62 is fixed to the rotor placement portion 12b using an adhesive or the like. The rotor facing portion 12c is arranged on the opposite load side with respect to the rotor 62. The rotor facing portion 12c is a stepped portion having an outer diameter larger than that of the rotor placement portion 12b toward the opposite load side. The flange portion 12d has a larger outer diameter than the rotor placement portion 12b and the rotor facing portion 12c. The rotor facing portion 12c is in contact with the rotor 62 from the anti-load side, and restricts the axial movement of the rotor 62 toward the anti-load side. The rotor facing portion 12c of this embodiment includes a protrusion 12e that protrudes toward the load side, and the protrusion 12e is in contact with the rotor 62.

The motor 14 includes a rotor 62 disposed on the rotating shaft 12, a stator 64 that cooperates with the rotor 62 to generate a rotating magnetic field that rotates the rotating shaft 12, and a motor housing 66 that houses the rotor 62, stator 64, etc. , is provided.

The rotor 62 has a cylindrical shape as a whole. The rotor 62 is, for example, a permanent magnet rotor including a rotor core 68 and a magnet (not shown) incorporated in the rotor core 68. The type of rotor 62 is not particularly limited, and may be a squirrel cage rotor, a wire-wound rotor, a coreless rotor, or the like. Furthermore, the rotor 62 may include a metal bush instead of the rotor core 68.

The stator 64 includes, for example, a stator core 70 and a coil (not shown) built into the stator core 70. The stator 64 is a slotted stator in which a slot (not shown) is formed in the stator core 70. The coil is wound around the teeth of stator core 70 so as to pass through the slot of stator core 70. Here, illustration of the slots of the stator core 70 is omitted, and the outline of the entire stator 64 is schematically shown. The type of stator 64 is not particularly limited, and may be a coreless stator in addition to a cored stator as in this embodiment. Further, the type of stator 64 may be a slotless stator or the like in addition to the slotted stator as in this embodiment. An annular gap 72 is provided between the stator 64 and the rotor 62.

The motor housing 66 includes a stator placement portion 66a in which the stator 64 is placed, an inner flange portion 66b provided on the load side of the stator placement portion 66a, and an anti-load side opening portion 66c that opens toward the anti-load side. . The stator 64 is fixed to the stator placement portion 66a using an interference fit (shrink fit), an adhesive, or the like. The inner flange portion 66b protrudes radially inward at the inner peripheral portion of the motor housing 66. An anti-load side bearing 74 that rotatably supports the rotary shaft 12 is arranged on the inner circumference of the inner flange portion 66b.

A hollow space 76 is provided within the hollow portion 12a of the rotating shaft 12. The hollow space 76 extends not only into the hollow portion 12a but also into the space between the rotating shaft 12 and the load-side cover 18. The load-side cover 18 separates a load-side external space 78 and a hollow space 76 on the load side of the actuator 10 in the axial direction X. The hollow space 76 of this embodiment is constituted by a radially outer space 80 provided between the hollow portion 12a of the rotating shaft 12 and the pipe member 42. The radially outer space 80 is separated from the counter-load-side external space 82 on the counter-load side of the actuator 10 by an internal seal member 84 disposed between the rotating shaft 12 and the pipe member 42 . The radially outer space 80 (hollow space 76) does not directly communicate with the anti-load side external space 82. The internal seal member 84 of this embodiment is incorporated into the internal bearing 44. In addition, the internal seal member 84 may be provided separately from the internal bearing 44.

A radially inner space 86 is provided inside the pipe member 42. The radial inner space 86 penetrates the inside of the pipe member 42 in the axial direction X, and communicates with the load side outer space 78 and the counter-load side outer space 82 .

The motor 14 includes a motor interior space 88 that accommodates the stator 64 and rotor 62. The motor internal space 88 includes a load side space 90 provided on the load side with respect to the rotor 62 and an anti-load side space 92 provided on the counter load side with respect to the rotor 62.

The load side space 90 is provided between the motor housing 66 and the rotating shaft 12. The load side space 90 is provided between the inner flange portion 66b of the motor housing 66 and the rotor 62 and stator 64.

The counter-load side space 92 is provided between the motor housing 66 and the rotating shaft 12. The counter-load side space 92 of this embodiment is provided at a position overlapping the stator 64 in the axial direction X on the counter-load side with respect to the stator 64. The counter-load side space 92 communicates with an external space through a discharge portion 112 (described later) of the actuator 10.

The speed reducer 16 includes a speed reducer internal space 96 sealed by a plurality of seal members 94A to 94C. A lubricant (not shown) used to lubricate the speed reduction mechanism 26 is sealed in the speed reducer internal space 96 . The seal members 94A to 94C of this embodiment include a first seal member 94A that separates the motor internal space 88 and the reducer internal space 96, a second seal member 94B that separates the reducer internal space 96 and the hollow space 76, and a reducer It includes a third seal member 94C that separates the internal space 96 and the load side external space 78. The reducer internal space 96 does not directly communicate with the motor internal space 88 and the hollow space 76, respectively. The first seal member 94A of this embodiment is incorporated into the anti-load side bearing 74, and the second seal member 94B is incorporated into the load side bearing 40. In addition, the first seal member 94A and the second seal member 94B may be provided separately from the

bearings

40, 74 as oil seals or the like.

Refer to Figures 2 to 4. The motor 14 includes a first air passage 100 provided between the rotating shaft 12 and the rotor 62. The first air passage 100 communicates the load side space 90 and the anti-load side space 92. The first air passage 100 is provided to guide air from the load side space 90 to the anti-load side space 92, as will be described later. The first air passage 100 of this embodiment directly communicates with the counter-load side space 92. In addition to this, the first air passage 100 may communicate with the counter-load side space 92 through another space (for example, the gap 72). The first air passage 100 includes an axial passage part 100a that extends in the axial direction, and a radial passage part 100b that is provided on the anti-load side space 92 side of the axial passage part 100a and extends in the radial direction. The axial passage portion 100a is open toward the load side, and the radial passage portion 100b is open toward the outside in the radial direction. A plurality of first air passages 100 are provided at intervals in the circumferential direction.

At least one of the rotating shaft 12 and the rotor 62 includes a first passage forming portion 102 that forms a first air passage 100 inside. The first passage forming part 102 of this embodiment is a groove, and is provided in the rotating shaft 12. Specifically, the first passage forming portion 102 is provided in the rotor placement portion 12b and the rotor facing portion 12c of the rotating shaft 12. The first passage forming part 102 forms an axial passage part 100a in the rotor arrangement part 12b, and a radial passage part 100b in the rotor facing part 12c. This means that the rotor 62 does not have the first passage forming portion 102 (groove) formed therein.

A second air passage 104 is provided between the inner circumference of the motor housing 66 and the outer circumference of the stator 64. The second air passage 104 communicates the load side space 90 and the anti-load side space 92 and extends in the axial direction X. The second air passage 104 is provided to circulate air between the load side space 90 and the anti-load side space 92. A plurality of second air passages 104 are provided at intervals in the circumferential direction. At least one of the motor housing 66 and the stator 64 includes a second passage forming portion 106 that forms a second air passage 104 inside. The second passage forming portion 106 of this embodiment is a groove portion, and is provided in the inner peripheral portion of the motor housing 66. The second passage forming portion 106 of the motor housing 66 extends further toward the load side than the load side end of the stator 64 and extends toward the opposite load side from the opposite end of the stator 64 .

The rotating shaft 12 includes a first air supply hole 108 that communicates the load-side space 90 within the motor 14 with the hollow portion 12a of the rotating shaft 12. The first air supply hole 108 is provided to supply air from the external space to the load side space 90 through the hollow space 76 within the rotating shaft 12 when guiding air through the first air passage 100 . The first air supply hole 108 penetrates the rotating shaft 12 in the radial direction. A plurality of first air supply holes 108 are provided at intervals in the circumferential direction of the rotating shaft 12. The first air supply hole 108 is provided individually corresponding to each of the plurality of first air passages 100. The first air supply hole 108 is provided on an axial extension of the first air passage 100 in the vicinity of the first air passage 100 corresponding to the first air supply hole 108 when viewed from the outside in the radial direction.

The load-side cover 18 includes a second air supply hole 110 that communicates the hollow space 76 (radially outer space 80) in the rotating shaft 12 with the load-side external space 78. The second air supply hole 110 is provided to supply air from the load-side external space 78 to the hollow space 76 within the rotating shaft 12 when air is guided through the first air passage 100 . The second air supply hole 110 penetrates the load side cover 18. A plurality of second air supply holes 110 are provided at intervals in the circumferential direction of the rotating shaft 12. The hollow space 76 does not communicate directly with the load-side external space 78, but communicates through the second air supply hole 110.

The actuator 10 includes a discharge section 112 provided on the opposite load side of the rotor 62. The discharge part 112 is used to discharge the air guided into the anti-load side space 92 by the first air passage 100 to the external space. The discharge portion 112 of this embodiment is constituted by the anti-load side opening 66c of the motor housing 66. In this case, the discharge section 112 discharges the air guided into the counter-load side space 92 to the counter-load side external space 82 .

The operation of the above actuator 10 will be explained. See FIG. 5. In this figure, the direction of air flow is indicated by an arrow. When the rotating shaft 12 rotates, centrifugal force acts on the air within the radial passage portion 100b of the first air passage 100. Due to this centrifugal force, the air in the radial passage portion 100b of the first air passage 100 is pushed outward in the radial direction and is supplied to the counter-load side space 92. Accordingly, the inside of the radial passage portion 100b of the first air passage 100 becomes negative pressure, and air is sucked into the first air passage 100 from the load side space 90. As a result, the first air passage 100 can guide air from the load side space 90 to the anti-load side space 92 through the first air passage 100 as the rotating shaft 12 rotates. The first air passage 100 can guide air in this way regardless of the rotational direction of the rotating shaft 12.

When air is sucked into the first air passage 100 from the load side space 90, the load side space 90 becomes a negative pressure, and air from the external space is supplied to the load side space 90 via the inside of the actuator 10. In this embodiment, air is supplied to the load side space 90 via the load side external space 78 → second air supply hole 110 → hollow space 76 (radially outer space 80) → first air supply hole 108 in this order. The air supplied to the counter-load side space 92 is discharged to the external space (here, the counter-load-side external space 82) through the discharge section 112. As a result, air flows in the order of external space (here, load-side external space 78) → load-side space 90 → first air passage 100 → counter-load-side space 92 → external space (here, counter-load-side external space 82). It is possible to generate forced convection.

In the process of generating such forced convection, the number and size of the plurality of first air supply holes 108 are adjusted so that a sufficient amount of air can be supplied to the load side space 90 inside the motor 14 through the first air supply holes 108. It is preferable that . In other words, the number and size of the first air supply holes 108 are preferably set so that when the rotating shaft 12 rotates, the load side space 90 has a predetermined allowable negative pressure or more. In addition, the number and size of the plurality of second air supply holes 110 are adjusted so that a sufficient amount of air can be supplied to the hollow space 76 in the rotating shaft 12 through the second air supply holes 110 in the process of generating forced convection. It is preferable that this is set. In other words, the number and size of the second air supply holes 110 are preferably set so that when the rotating shaft 12 rotates, the hollow space 76 has a predetermined allowable negative pressure or more. Thereby, it is possible to prevent a reduction in transmission efficiency due to excessively negative pressure in the load-side space 90 in the motor 14 and the hollow space 76 in the rotating shaft 12. Note that the number of first air supply holes 108 and second air supply holes 110 is not particularly limited, and may be one.

The effects of the above actuator 10 will be explained.

The first air passage 100 is capable of guiding air from the load side space 90 to the anti-load side space 92 through the first air passage 100 as the rotating shaft 12 rotates. Thereby, forced convection can be generated in which air flows in the order of load side space 90 → first air passage 100 → anti-load side space 92. Thereby, the internal parts of the motor 14 can be cooled by dissipating the heat of the internal parts of the motor 14 (such as the rotor 62) to the forced convection air. In particular, the rotor 62 can be effectively cooled by directly dissipating the heat of the rotor 62, which is a heat source, to the air flowing through the first air passage 100.

In this embodiment, forced convection is generated to discharge air taken in from the external space outside the actuator 10 into the external space. Therefore, the heat of the motor 14 can be released to the cold air taken in from the outside space, and the internal parts of the motor 14 can be effectively cooled.

Furthermore, since the internal parts of the motor 14 can be cooled, the frequency of derating control that suppresses the motor supply current when the temperature exceeds an allowable temperature can be reduced, and the actuator 10 can continuously output large torque. Further, since the internal parts of the motor 14 can be cooled, the output (rotational speed) of the motor 14 can be increased by increasing the motor supply current while suppressing the temperature rise of the internal parts of the motor 14. Accordingly, by increasing the reduction ratio of the reducer 16, it becomes possible to output even larger torque from the actuator 10 while maintaining the rotational speed of the output rotation of the actuator 10. Further, when cooling the motor 14, a dedicated power source, a coolant circulation circuit, a fan, and other dedicated components for cooling can be eliminated, and an increase in the size of the actuator 10 can be avoided.

The rotating shaft 12 includes a first passage forming portion 102 that forms a first air passage 100 inside. Therefore, when providing the first air passage 100, it is not necessary to form the first passage forming part 102 in the rotor 62.

The actuator 10 includes a discharge section 112 that discharges the air guided into the counter-load side space 92 by the first air passage 100 to the external space. Therefore, the air heated by cooling the internal parts of the motor 14 can be released from the anti-load side space 92 to the outside space, and new air can be easily introduced into the load side space 90.

The rotating shaft 12 includes a first air supply hole 108 that communicates the load-side space 90 within the motor 14 with the hollow portion 12a of the rotating shaft 12. Therefore, when the rotating shaft 12 rotates, air can be supplied to the load side space 90 through the hollow portion 12a of the rotating shaft 12.

The load-side cover 18 includes a second air supply hole 110 that communicates the hollow space 76 in the hollow portion 12a of the rotating shaft 12 with the load-side external space 78. Normally, the load-side external space 78 is in a high-temperature environment because it is located near heat sources such as the motor 14 and the driver board 52. On the other hand, the counter-load-side external space 82 is usually in a lower temperature environment than the load-side external space 78 because there is often no heat source nearby like the load-side external space 78 . The air in the load-side external space 78, which is colder than the counter-load-side external space 82, can be supplied to the load-side space 90 inside the motor 14 through the second air supply hole 110 and the first air supply hole 108. As a result, the internal parts of the motor 14 can be effectively cooled using cold air.

A second air passage 104 is provided between the motor housing 66 and the stator 64, which communicates the load side space 90 and the counter-load side space 92. Therefore, when air is guided from the load side space 90 to the anti-load side space 92 by the first air passage 100, the air can be circulated through the second air passage 104. Furthermore, the stator 64 can be effectively cooled by directly dissipating the heat of the stator 64, which is a heat source, to the air flowing through the second air passage 104.

Next, other features of the first air passage 100 will be explained. See FIG. 2. The first air passage 100 includes a slope 120 whose outer diameter gradually increases toward the anti-load side. The slope 120 constitutes the bottom of the first passage forming portion 102 of the first air passage 100. By providing the slope 120 in the first air passage 100, the air in the first air passage 100 can be greatly accelerated when the air is guided through the first air passage 100. Further, by providing the slope 120 in the first air passage 100, air can be circulated along the slope 120 while maintaining a high air flow velocity. As will be described later, this is new knowledge obtained as a result of fluid analysis performed by the inventor of the present application. Thereby, it becomes possible to supply air at a high flow rate to the counter-load side space 92, and the amount of air released from the counter-load side space 92 to the external space can be increased. Accordingly, the supply amount of air taken into the actuator 10 from the external space can be increased, and the internal parts of the motor 14 can be effectively cooled.

The slope 120 includes a first region 120a provided on the radially inner side of the rotor 62. By providing such a first region 120a on the slope 120, the cross-sectional area of the first air passage 100 (axial passage portion 100a) can be gradually reduced toward the anti-load side. Therefore, the air can be gradually accelerated in the process of flowing through the axial passage portion 100a of the first air passage 100. Further, in this case, air can be rectified during the process of flowing through the axial passage portion 100a of the first air passage 100, and air at a high flow rate can be stably supplied to the counter-load side space 92. As will be described later, this is new knowledge obtained as a result of fluid analysis performed by the inventor of the present application.

The slope 120 includes a second region 120b provided on the opposite load side from the rotor 62. The rate of change in the outer diameter of the second region 120b is greater than the rate of change in the outer diameter of the first region 120a. The rate of change here refers to the amount of change (%) in the outer diameter per unit axial dimension, that is, the slope. The slope 120 of this embodiment includes, from the load side toward the anti-load side, a first constant slope portion 120c, a slope changing portion 120d, and a second constant slope portion 120e. The slopes of the first constant slope portion 120c and the second constant slope portion 120e are constant, and the slope of the slope changing portion 120d gradually increases toward the anti-load side. A boundary 120f between the first region 120a and the second region 120b is provided at the gradient changing portion 120d.

When the second region 120b of the slope 120 is provided in this way, even if the axial cross-sectional area increases immediately after passing through the axial passage portion 100a of the first air passage 100, the air passes through the axial passage portion 100a. The air can now be accelerated more than immediately before (region R2 in FIG. 6(B)). In particular, when the rate of change in the outer diameter of the second region 120b is made larger than the rate of change in the outer diameter of the first region 120a, there is a tendency that the air can be greatly accelerated immediately after passing through the axial passage portion 100a. As will be described later, this is also new knowledge obtained as a result of fluid analysis conducted by the inventor of the present application.

The second region 120b of the slope 120 continues beyond the opposite end 100c of the first air passage 100 to the outer circumference of the flange 12d of the rotating shaft 12. The outer diameter R120 of the anti-load side end 120g of the second region 120b of the slope 120 is larger than the outer diameter R62 of the rotor 62. This outer diameter R120 is larger than the inner diameter R64-1 of the stator 64 and smaller than the outer diameter R64-2 of the stator 64. This outer diameter R120 has a size that matches the outer diameter R12 (maximum outer diameter of the rotating shaft 12) of the flange portion 12d of the rotating shaft 12. In this way, by making the outer diameter R120 of the slope 120 larger than the outer diameter R62 of the rotor 62, it becomes easier to circulate the air close to the external space in the anti-load side space 92 while maintaining a high air flow velocity. Furthermore, by increasing the amount of air released into the external space, it becomes easier to increase the amount of air taken in from the external space, and the internal parts of the motor 14 can be cooled more effectively. Note that the outer diameter R120 of the slope 120 may be greater than or equal to the outer diameter R64-2 of the stator 64.

As described above, the presence of the slope 120 in the first air passage 100 makes it possible to supply air with high flow velocity and momentum to the anti-load side space 92 and then release it from the release part 112. At this time, by designing the first air passage 100 so that the minimum cross-sectional area is small, the amount of air from the first air passage 100 to the counter-load side space 92 is reduced relative to the amount of air released from the counter-load side space 92. The amount of supply can be reduced. Accordingly, the air pressure in the anti-load side space 92 can be lowered with respect to the load side space 90 while increasing the pressure difference, and air can be supplied from the load side space 90 to the anti-load side space 92 through locations other than the first air passage 100. It will be possible to distribute it. This effect can be obtained more effectively as the number of first air passages 100 increases. The minimum cross-sectional area of the first air passage 100 here refers to the cross-sectional area at a point where the cross-sectional area orthogonal to the air flow direction within the first air passage 100 is minimum, and here, the axial passage section Refers to the cross-sectional area of the opposite end of 100a.

In this embodiment, "a location other than the first air passage 100" herein refers to the second air passage 104 located between the motor housing 66 and the stator 64. The structure (number, minimum cross-sectional area, etc.) of the first air passage 100 is designed (configured) so that when the rotating shaft 12 rotates, air flows through the second air passage 104 from the load side to the anti-load side. It can be said that Thereby, the stator 64 can be effectively cooled by directly dissipating the heat of the stator 64 to the air flowing through the second air passage 104. The structure (number, minimum cross-sectional area, etc.) of the first air passage 100 suitable for satisfying such conditions may be determined by experiment, analysis, or the like.

Furthermore, the "location other than the first air passage 100" here refers to the gap 72 between the rotor 62 and the stator 64. The structure (number, minimum cross-sectional area, etc.) of the first air passage 100 is designed (configured) so that when the rotating shaft 12 rotates, air flows through the gap 72 from the load side to the anti-load side. I can say that. Thereby, the heat of the stator 64 and rotor 62 can be directly released to the air flowing through the gap 72, thereby making it possible to effectively cool them. The structure (number, minimum cross-sectional area, etc.) of the first air passage 100 suitable for satisfying such conditions may be determined by experiment, analysis, or the like.

Next, an example of the results of fluid analysis performed to confirm the flow of air when the slope 120 is provided will be described. FIGS. 6A and 6B show the results of a fluid analysis performed on a model having a shape similar to that of the actuator 10 described in the first embodiment. This fluid analysis was performed under the condition that the rotating shaft 12 was rotated. In FIG. 6(A), the direction of air flow is indicated by an arrow. Further, in FIG. 6(A), hatched areas are shown where air flows at a high flow rate. The hatched locations are locations where the flow velocity is several times (for example, 3 or 4 times) higher than the non-hatched locations with arrows. Moreover, FIG. 6(B) schematically shows the flow direction of air within the first air passage 100.

In this way, when the slope 120 is provided in the first air passage 100, the air within the first air passage 100 can be greatly accelerated. At this time, although turbulence occurred in the air in the region R1 immediately after the air entered the first air passage 100, the turbulence in the air stopped as it moved toward the opposite load side. Further, in the axial passage portion 100a of the first air passage 100, the slope 120 has the first region 120a, so that the air flow rate is gradually accelerated to become higher. Furthermore, in the region R2 of the radial passage portion 100b immediately after passing through the axial passage portion 100a of the first air passage 100, even if the axial cross-sectional area is expanded due to the second region 120b in the slope 120. , air was flowing at a maximum flow velocity that was faster than that immediately before. Further, after passing through the region R2 of the radial passage portion 100b of the first air passage 100, the air was flowing along the slope 120 while maintaining a relatively high flow velocity, although the flow velocity was gradually lowered. . In addition to this, air was flowing through the gap 72 and the second air passage 104 from the load side to the anti-load side.

(Second Embodiment) Refer to FIG. 7. In this figure as well, the direction of air flow is indicated by an arrow. The actuator 10 of this embodiment is different from the actuator 10 of the first embodiment in the pipe member 42. The pipe member 42 of this embodiment includes a third air supply hole 130 that communicates between a radially outer space 80 on the outside and a radially inner space 86 on the inside. The third air supply hole 130 penetrates the pipe member 42 in the radial direction. A plurality of third air supply holes 130 are provided at intervals in the circumferential direction of the rotating shaft 12.

When guiding air through the first air passage 100, the third air supply hole 130 directs air from the load-side external space 78 and the counter-load-side external space 82 to the radially outer space 80 within the hollow portion 12a of the rotating shaft 12. used to supply In this embodiment, when guiding air through the first air passage 100, the load-side external space 78 and the counter-load-side external space 82 → the radially inner space 86 → the third air supply hole 130 → the radially outer space 80 → the third Air that has passed through the air supply holes 108 in order is supplied to the load side space 90 within the motor 14. Note that the load side cover 18 of this embodiment does not include the second air supply hole 110.

According to this embodiment, air in the counter-load side external space 82 and the load side space 90 can be supplied to the load side space 90 inside the motor 14 through the third air supply hole 130 and the first air supply hole 108. The actuator 10 of this embodiment can obtain the same effects as the first embodiment in other respects.

(Third Embodiment) Refer to FIG. 8. The actuator 10 of this embodiment differs from the first embodiment in the second air passage 104. Specifically, the second passage forming portion 106 that forms the second air passage 104 of this embodiment is provided on the outer periphery of the stator 64 (the outer periphery of the stator core 70) instead of the motor housing 66. In addition to this, the second passage forming portion 106 may be provided in both the motor housing 66 and the stator 64. The actuator 10 of this embodiment can also provide the same effects as the first embodiment.

(Fourth Embodiment) Refer to FIGS. 9 and 10. The actuator 10 of this embodiment is different from the first embodiment in that it includes a plurality of blades 140 arranged in the load side space 90. The plurality of blades 140 protrude radially outward from the outer peripheral portion of the rotating shaft 12 and are integrated with the rotating shaft 12 . The plurality of blades 140 of this embodiment are fixed to a hub 142 fixed to the outer circumference of the rotating shaft 12 by interference fit or the like. The actuator 10 can also be said to include a fan 144 having blades 140 and a hub 142. The hub 142 includes a through hole 142a that penetrates in the radial direction at a position overlapping with the first air supply hole 108. The through hole 142a communicates the load side space 90 and the hollow space 76 through the first air supply hole 108. In addition to this, the plurality of blades 140 may be integrally formed as part of the rotating shaft 12.

By rotating together with the rotating shaft 12, the plurality of blades 140 can guide air in the hollow space 76 within the rotating shaft 12 to the load-side space 90 through the first air supply hole 108. Thereby, the amount of air supplied from the external space through the hollow space 76 of the rotary shaft 12 into the load side space 90 can be increased. As a result, the internal parts of the motor 14 can be cooled more effectively. The actuator 10 of this embodiment can obtain the same effects as the first embodiment in other respects.

Next, modifications of each component explained so far will be explained.

The reducer 16 is not essential in the actuator 10, and it is sufficient if the actuator 10 is provided with the motor 14. A specific example of the speed reduction mechanism 26 of the speed reducer 16 is not particularly limited. The speed reduction mechanism 26 may be, for example, a simple planetary gear mechanism, an eccentric oscillating gear mechanism, an orthogonal axis gear mechanism, a parallel axis gear mechanism, or the like. When the speed reduction mechanism 26 is an eccentric rocking type gear mechanism, the specific example of the type thereof is not particularly limited. This type may include a center crank type in which the crankshaft is arranged on the axis of the internal gear, or a distributed type in which a plurality of crankshafts are arranged at positions offset from the axis of the internal gear. When the speed reduction mechanism 26 is a flexible mesh gear mechanism, the specific example of the type thereof is not particularly limited. This type may be a cylindrical type having two

internal gears

32A, 32B as in this embodiment, or a cup type or top hat type having one internal gear, for example.

The first air passage 100 only needs to be able to guide air from the load side space 90 to the anti-load side space 92 through the first air passage 100 along with the rotating shaft 12, and its specific shape is not particularly limited. For example, the first air passage 100 may include only an axial passage portion 100a extending spirally. In this case, air can be guided from the load side space 90 to the anti-load side space 92 by rotating it toward the anti-load side in a direction opposite to the spiral winding direction formed by the first air passage 100.

The motor internal space 88 does not need to communicate with the external space. In this case, when air is guided through the first air passage 100, the air may be circulated in the order of the load side space 90→first air passage 100→counter-load side space 92→load side space 90. Even in this case, the effect of cooling the internal parts of the motor 14 can be expected due to forced air convection and heat conduction. Heat conduction here refers to heat conduction between the motor interior space 88 and the exterior space through the motor housing 66.

The first passage forming portion 102 may be provided on the rotor 62 instead of the rotating shaft 12. In addition to this, the first passage forming portion 102 may be provided on both the rotating shaft 12 and the rotor 62.

The slope 120 is not essential in the first air passage 100. The slope 120 may include at least one of a second region 120b and a first region 120a. The rate of change in the outer diameters of the second region 120b and the first region 120a is not particularly limited. The rate of change in both regions may be the same, or the rate of change in the second region 120b may be smaller than the rate of change in the first region 120a.

The specific example of the discharge section 112 is not particularly limited. This may be, for example, in addition to the anti-load side opening 66c of the motor housing 66, a through hole formed in the motor housing 66, an exhaust pipe attached to the motor housing 66, or the like.

The specific route for supplying air to the load-side space 90 in the motor 14 through the first air supply hole 108 is not particularly limited. As this route, the following (1) was explained in the first embodiment, and the following (2) was explained in the second embodiment. In addition to this, this route may be realized by, for example, the following (3) and (4). Furthermore, two or more of (1) to (3) may be combined.
(1) Load side external space 78 → second air supply hole 110 → hollow space 76 (radially outer space 80) → first air supply hole 108
(2) At least one of the load side external space 78 and the counter-load side external space 82 → radially inner space 86 → third air supply hole 130 → hollow space 76 (radially outer space 80) → first air supply hole 108
(3) (When the third seal member 94C is not arranged between the rotating shaft 12 and the pipe member 42) Anti-load side external space 82 → hollow space 76 (radially outer space 80) → first air supply hole 108
(4) (When the pipe member 42 is not arranged in the hollow part 12a of the rotating shaft 12) At least one of the load side external space 78 and the counter-load side external space 82 → hollow space 76 → first air supply hole 108

The second air passage 104 is not essential in the actuator 10. In order to circulate the air through the second air passage 104, when the air is guided through the first air passage 100, the air may circulate from the counter-load side space 92 to the load side space 90. It is not essential that the first air passage 100 be designed so that air flows through the second air passage 104 and the gap 72.

The above embodiments and modifications are merely examples. These abstracted technical ideas should not be interpreted as being limited to the contents of the embodiments and modified forms. The contents of the embodiments and modified forms may be subject to many design changes such as changes, additions, and deletions of constituent elements. In the embodiments described above, the content that allows such design changes is emphasized by adding the notation "embodiment". However, design changes are allowed even if there is no such notation. The hatching added to the cross section of the drawing does not limit the material of the hatched object. The structures referred to in the embodiments and modified embodiments naturally include structures that can be considered to be the same considering dimensional errors, assembly errors, and the like.

Any combination of the above components is also effective. For example, an embodiment may be combined with any description of another embodiment, or a modified form may be combined with any description of the embodiment and other modified forms. Further, in the embodiment, a component made up of a single member may be made up of a plurality of members. Similarly, a component configured with multiple members in an embodiment may be configured with a single member.

The present disclosure relates to an actuator.

DESCRIPTION OF SYMBOLS 10...Actuator, 12...Rotating shaft, 12a...Hollow part, 14...Motor, 16...Reducer, 18...Load side cover, 42...Pipe member, 62...Rotor, 64...Stator, 66...Motor housing, 72...Gap , 76...Hollow space, 78...Load side external space, 80...Radially outer space, 86...Radially inner space, 90...Load side space, 92...Counter load side space, 100...First air passage, 104...Nth 2 air passage, 108...first air supply hole, 110...second air supply hole, 112...discharge part, 120...slope, 120a...first region, 120b...second region, 130...third air supply hole.

Claims

An actuator comprising a rotating shaft and a motor that rotates the rotating shaft,
The motor includes a rotor disposed on the rotating shaft, a load-side space provided between the rotating shaft and the rotor, and a load-side space located on a load side with respect to the rotor, and an anti-load-side space located on a counter-load side with respect to the rotor. A first air passage communicating with each other,
The first air passage is an actuator capable of guiding air from the load side space to the counter-load side space through the first air passage as the rotating shaft rotates.
The actuator according to claim 1, wherein the rotating shaft includes a passage forming part that forms the first air passage inside.
The actuator according to claim 1 or 2, wherein the first air passage includes a slope whose outer diameter gradually increases toward the anti-load side.
The actuator according to claim 3, wherein the slope includes a first region provided radially inside the rotor.
The actuator according to claim 3 or 4, wherein the slope includes a second region provided on a side opposite to the load from the rotor.
The actuator according to claim 5, wherein the outer diameter of the opposite end of the second region is larger than the outer diameter of the rotor.
The slope includes a second region provided on the opposite load side of the rotor,
The actuator according to claim 4, wherein a rate of change in the outer diameter of the second region is greater than a rate of change in the outer diameter of the first region.
The actuator according to any one of claims 1 to 7, further comprising a discharge section that is provided on a side opposite to the load side of the rotor and discharges the air guided into the space on the opposite load side by the first air passage to an external space.
The actuator according to any one of claims 1 to 8, wherein the rotating shaft includes a hollow portion and a first air supply hole that communicates the load-side space with the hollow portion.
a reducer connected to the load side of the motor;
a load side cover that covers the reduction gear from the load side,
The actuator according to claim 9, wherein the load-side cover includes a second air supply hole that communicates a hollow space in the hollow portion with a load-side external space.
comprising a pipe member disposed within the hollow part,
The actuator according to claim 9, wherein the pipe member includes a third air supply hole that communicates a radially outer space between the hollow portion and the pipe member and a radially inner space inside the pipe member. .
The motor includes a motor housing and a stator fixed to an inner peripheral portion of the motor housing,
The actuator according to any one of claims 1 to 11, wherein a second air passage is provided between the motor housing and the stator to communicate the load side space and the counter-load side space.
The actuator according to claim 12, wherein the first air passage is designed so that when the rotating shaft rotates, air flows through the second air passage from the load side toward the anti-load side.
Claim 12 or 13, wherein the first air passage is designed such that when the rotating shaft rotates, air flows through the gap between the rotor and the stator from the load side to the opposite load side. Actuator as described.