JP2023100023A - Rotation device - Google Patents

Abstract

To suitably use a dry type brake with a simple configuration.SOLUTION: A rotation device 1 includes: a rotation shaft 21; a lubricant-filled space S1 which stores at least a part of the rotation shaft 21 and in which lubricant is filled; a brake 40 which is a dry type brake for braking or holding rotation of the rotation shaft 21; and a brake storage space S2 which stores the brake 40. Lubricant is communicated between the lubricant-filled space S1 and the brake storage space S2 so that lubricant can be circulated.SELECTED DRAWING: Figure 1

Description

The present invention relates to rotating devices.

2. Description of the Related Art Conventionally, there is known a rotary device including a speed reducer or the like using a lubricant and a dry brake (see, for example, Patent Document 1). In this type of rotating device, in general, contact seals such as seal bearings and oil seals, or labyrinth seals are installed between the reduction gear and the dry brake for the purpose of preventing lubricant from leaking from the reduction gear to the dry brake. A contactless seal is provided.

Japanese Patent Application Laid-Open No. 2021-97430

However, when a contact seal is provided, power loss increases, and when a non-contact seal is provided, the structure becomes complicated.
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to suitably use a dry brake with a simple structure.

The present invention includes a rotating shaft, a lubricant enclosing space that accommodates at least a portion of the rotating shaft and encloses a lubricant, a dry brake that brakes or holds the rotation of the rotating shaft, and the dry brake. A rotating device having a brake storage space,
Lubricant is communicated between the lubricant enclosing space and the brake housing space.

According to the present invention, a dry brake can be suitably used with a simple configuration.

It is a sectional view showing a rotating device concerning an embodiment. (a) It is an enlarged view of the periphery of a brake in FIG. 1, (b) It is the figure which looked at the principal part of the brake from the axial direction. (a) It is a figure which shows the apparatus image of a torque measurement test, (b) It is a figure which shows the example of a torque waveform at the time of a measurement. It is a figure which shows the result of a torque measurement test.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Overall Configuration of Rotating Device]
FIG. 1 is a cross-sectional view showing a rotating device 1 according to this embodiment.
As shown in this figure, the rotating device 1 according to the present embodiment is an actuator that outputs rotational power, and includes an output shaft 11, a motor 20, a reduction gear 30, a brake 40, a rotation detection section 50, and a circuit section 60. .
Among them, the output shaft 11 is rotatably supported around the central axis Ax and penetrates through the center of the rotary device 1 over substantially the entire length thereof. On the other hand, the speed reducer 30 , the brake 40 , the motor 20 , the rotation detector 50 and the circuit section 60 are arranged in this order along the central axis Ax of the output shaft 11 .
In the following description, the direction along the central axis Ax is called the "axial direction", the direction perpendicular to the central axis Ax is called the "radial direction", and the direction of rotation about the central axis Ax is called the "circumferential direction". In the axial direction, the side connected to the driven member (not shown) (left side in the figure) is called the "output side", and the side opposite to the output side (right side in the figure) is called the "counter-output side". ”.

[Motor configuration]
The motor 20 includes a rotating shaft 21 , a motor rotor 22 , a motor stator 23 and a motor casing 24 .
The rotary shaft 21 has a hollow structure, is arranged concentrically on the outer peripheral side of the output shaft 11, and is rotatably supported.
The motor rotor 22 is fixed to the outer peripheral surface of the rotating shaft 21 and rotates integrally with the rotating shaft 21 . The motor rotor 22 is, for example, a permanent magnet such as a neodymium magnet, and a plurality of magnets corresponding to a predetermined number of poles are arranged in the circumferential direction.
The motor stator 23 is configured by winding a coil around a stator core made of, for example, laminated steel plates. The motor stator 23 is concentrically arranged on the outer peripheral side of the motor rotor 22 .

The motor casing 24 covers the outer peripheral side of the motor rotor 22 and the motor stator 23, and the motor stator 23 is fitted in the inner peripheral surface. A heat radiating fin 24 a is erected on the outer peripheral surface of the motor casing 24 . The motor casing 24 is made of aluminum, although not particularly limited, solely for the purpose of reducing weight and improving cooling performance.
The type of the motor 20 is not particularly limited, and may be, for example, an induction motor instead of a permanent magnet type.

[Structure of reducer]
The speed reducer 30 is a cylindrical flexural mesh speed reducer in this embodiment, and is arranged on the output side of the motor 20 and the brake 40 . Specifically, the speed reducer 30 includes a vibration generator shaft 31, an external gear 32, a first internal gear 33G and a second internal gear 34G, a speed reducer casing 33, an internal gear member 34, a first cover 35 and A second cover 36 is provided.
The vibration generator shaft 31 has a hollow structure, is concentrically arranged on the outer peripheral side of the output shaft 11, and is rotatably supported by a first bearing 37a and a second bearing 37b (for example, both are ball bearings). there is The vibration generator shaft 31 is connected (for example, spline-connected) to the rotating shaft 21 and rotates together with the rotating shaft 21 . The vibrating body shaft 31 has a vibrating body 31a having a non-circular (for example, elliptical) outer shape in a cross section perpendicular to the central axis Ax.
The external gear 32 is a flexible cylindrical member centered on the central axis Ax, and has teeth on its outer periphery. The external gear 32 is rotatable relative to the vibrating body 31a by means of a vibrating body bearing 31B arranged between the external gear 32 and the vibrating body 31a.

The first internal gear 33G and the second internal gear 34G rotate around the central axis Ax around the vibrating body 31a. The first internal gear 33G and the second internal gear 34G are arranged side by side in the axial direction and mesh with the external gear 32 . The first internal gear 33</b>G and the second internal gear 34</b>G are configured by providing internal teeth at corresponding portions of the inner peripheral portions of the speed reducer casing 33 and the internal gear member 34 .
The speed reducer casing 33 covers the outer diameter side of the external gear 32 .
The internal gear member 34 is connected with a first output member 38a arranged on its output side. The first output member 38a rotatably supports the vibration generator shaft 31 via the second bearing 37b. The first output member 38a is connected to a second output member 38b arranged on its output side. The second output member 38b is connected together with the output shaft 11 to a driven member (not shown).

The first cover 35 is arranged on the counter-output side of the speed reducer casing 33 and is connected to the speed reducer casing 33 and the brake casing 48 . The first cover 35 rotatably supports the vibration generator shaft 31 via a first bearing 37a.
The second cover 36 is arranged and connected to the output side of the speed reducer casing 33 . The second cover 36 covers the outer peripheral side of the second output member 38b, and rotatably supports the second output member 38b via a main bearing 36B (for example, a cross roller bearing).

Also, in the speed reducer 30, grease (lubricant) is enclosed in an internal space (hereinafter referred to as a "lubricant enclosed space") S1 closed by an O-ring or an oil seal. Specifically, the lubricant enclosure space S1 includes O-rings 39a and 39b arranged between the speed reducer casing 33, the first cover 35 and the second cover 36, the second cover 36 and the second output member 38b. It is an internal space of the speed reducer 30 (storage space of the speed reducer mechanism) sealed by an oil seal 39c arranged therebetween and the first bearing 37a and the second bearing 37b.
However, although the first bearing 37a is not particularly limited, it is not a sealed type but an open type ball bearing, and allows the lubricant to flow through the first bearing 37a. Note that the first bearing 37a is not limited to an open bearing, and may be a roller bearing, for example. Also, the first bearing 37 a may not be arranged on the first cover 35 , and may be arranged at another position, for example, on the anti-load side of the motor 20 .

[Brake configuration]
The brake 40 is a contact (friction) dry brake that does not actively supply lubricant. Here, a dry brake is a type of brake in which lubricating oil is not enclosed in the housing space of each component of the brake mechanism, and a wet brake of the type in which lubricating oil is sealed in the housing space of each component of the brake mechanism. distinguished. In other words, in the dry brake, in a steady state (normal state) in which the lubricant leaked from the speed reducer 30 is not infiltrated, lubricating oil does not enter the housing space of each component of the brake mechanism. It can be said that it is a type of brake that is not enclosed. This brake 40 is arranged between the motor 20 and the reduction gear 30 . Also, the brake 40 of the present embodiment is, although not particularly limited, a holding brake that holds the rotating shaft 21 in a stopped state. That is, in the actuator of this embodiment, as will be described later, the rotation shaft 21 is stopped by the control of the motor 20, and the stopped state is maintained by the brake 40 after the rotation of the rotation shaft 21 has completely or substantially stopped. .

Specifically, the brake 40 includes a hub member 41 , a rotor 42 , an armature 43 , an electromagnetic coil 44 , a plate 46 , a frame 47 and a brake casing 48 .
The hub member 41 is fixed (for example, connected by a key) to the rotary shaft 21 extending from the motor 20 to the inside of the brake 40, and the rotor 42 is formed in a disc shape and spline-connected to the hub member 41 (see FIG. 2(b)). Therefore, the rotor 42 rotates integrally with the hub member 41 and the rotating shaft 21 .

The armature 43 is arranged on the output side of the rotor 42 and supported so as to be axially displaceable so as to contact and separate from the rotor 42 . On the other hand, a plate 46 is arranged on the counter-output side of the rotor 42 and supported by a frame 47 . Two friction materials (linings) 43a and 46a are fixed to the surfaces of the armature 43 and the plate 46 that face the rotor 42 in the axial direction. Of these, the one provided on the armature 43 is a movable friction material (first friction material) 43a, and the one provided on the plate 46 is a fixed friction material (second friction material) 46a. The friction members 43 a and 46 a may be provided on both axial side surfaces of the rotor 42 .

The electromagnetic coil 44 is an example of a brake coil member according to the present invention, and is arranged on the output side of the armature 43, that is, closer to the lubricant filling space S1 than the two friction members 43a and 46a. The electromagnetic coil 44 attracts the armature 43 by magnetic force generated by energization and moves it in the axial direction, thereby bringing the movable friction member 43 a into contact with and separating from the rotor 42 .
The frame 47 is supported by the brake casing 48 and holds the electromagnetic coil 44, the plate 46, and the like.

The brake casing 48 is fixed to the motor casing 24 and the first cover 35 of the speed reducer 30 . A heat radiating fin 48 a is erected on the outer peripheral surface of the brake casing 48 .
The interior of the brake casing 48 forms a brake housing space S2 for housing each component of the brake 40 . Specifically, the brake housing space S2 is a space inside the brake casing 48, and refers to a space extending to the motor 20 on the non-output side and to the first cover 35 and the first bearing 37a of the speed reducer 30 on the output side. However, as described above, since the first bearing 37a is not a sealed bearing, the lubricant is communicated between the lubricant enclosing space S1 in the speed reducer 30 and the brake storage space S2 in the brake 40 so that the lubricant can flow. there is Here, "the lubricant is in fluid communication" means that there is no structure having a sealing function between the lubricant enclosing space S1 and the brake housing space S2, i.e., the contact type seal member itself. Needless to say, there is no non-contact type seal such as a labyrinth seal.

In the brake 40, as shown in FIG. 2A, the first radial gap G1 between the rotor 42 and the rotating shaft 21 (including the hub member 41 that rotates integrally with the rotating shaft 21) is filled with lubricant. It is smaller than the smallest second radial gap G2 in the route from the enclosed space S1 to the movable friction member 43a on the lubricant enclosed space S1 side of the two friction members.
More specifically, since the rotor 42 and the hub member 41 that rotates integrally with the rotating shaft 21 are spline-connected as described above, the first radial gap G1 is formed by the meshing of the splines, as shown in FIG. 2(b). It is a gap. On the other hand, the second radial gap G2 is a gap between the armature 43 and the rotating shaft 21 in this embodiment. Therefore, the first radial clearance G1, which is the meshing clearance of the splines, is smaller than the second radial clearance G2, which is the normal clearance between parts.
Therefore, when the lubricant enters the brake housing space S2 from the lubricant enclosing space S1 through the first bearing 37a, the lubricant relatively easily reaches the movable friction member 43a on the output side, and the fixed friction on the anti-output side. It is relatively difficult for the lubricant to reach the material 46a. Therefore, even if lubricant enters (adheres to) one friction material 43a, it is possible to suppress the lubricant from entering the other friction material 46a. force) can be suppressed.

In the brake 40 having the above configuration, the rotor 42 is sandwiched between the armature 43 and the plate 46 via the respective friction materials 43a and 46a by the action of the electromagnetic coil 44, so that the braking force ( retention force) is applied. Conversely, the action of the electromagnetic coil 44 releases the force with which the rotor 42 is sandwiched between the armature 43 and the plate 46, so that the braking force (holding force) on the rotating shaft 21 is released.
The brake 40 of this embodiment is a non-excitation type brake, and when the electromagnetic coil 44 is not energized, it is actuated by the biasing force of a spring (not shown), and the rotor 42 is pressed by the armature 43 to stop the rotating shaft 21. hold in state.

[Configuration of Rotation Detection Unit and Circuit Unit]
As shown in FIG. 1 , the rotation detector 50 is arranged on the counter-output side of the motor 20 . The rotation detector 50 has an input-side rotation detector 51 that detects rotation of the rotary shaft 21 and an output-side rotation detector 52 that detects rotation of the output shaft 11 . These are housed in a detector casing 53 fixed to the brake casing 48 .
The input-side rotation detector 51 has a rotating portion 51a that rotates integrally with the rotating shaft 21, and a sensor 51b that is arranged near the rotating portion 51a and detects the amount of rotation. The output-side rotation detector 52 has a rotating portion 52a that rotates integrally with the output shaft 11, and a sensor 52b that is arranged near the rotating portion 52a and detects the amount of rotation. The input-side rotation detector 51 and the output-side rotation detector 52 are, for example, rotary encoders that output the rotational displacement of the rotating portion as digital signals, but may be resolvers that output as analog signals, or other types of encoders. It may be a rotation detector. The rotary encoder may be configured to have an optical detection section, or may be configured to have a magnetic detection section. The input-side rotation detector 51 and the output-side rotation detector 52 may be different types of detectors.

In the input side rotation detector 51 and the output side rotation detector 52, the two sensors 51b and 52b are mounted on the encoder board of the circuit section 60, and the two rotating sections 51a and 52a are mounted on the output side of the circuit section 60. are placed facing each other. More specifically, the installation position of the rotating part 52a on the output shaft 11 and the installation position of the rotating part 51a on the rotating shaft 21 are substantially the same in the axial direction. 52b are arranged at substantially the same position in the axial direction.

The circuit section 60 is arranged on the counter-output side of the rotation detection section 50 . A motor driver board on which a drive circuit for the motor 20 is mounted, an encoder board on which a detection circuit of the rotation detection section 50 is mounted, and the like are arranged in the circuit section 60 . These are housed in the circuit section casing 61 . The circuit unit casing 61 rotatably supports the output shaft 11 via a bearing 62 .

[Operation of rotating machine]
In the rotating device 1 of the present embodiment, first, at the start of operation, the electromagnetic coil 44 of the brake 40 is energized, and the holding force of the armature 43 on the rotating shaft 21 (rotor 42) is released. In this state, when the motor 20 is driven by the circuit unit 60 and the rotating shaft 21 rotates, the vibrating body shaft 31 of the speed reducer 30 integrally formed with the rotating shaft 21 also rotates, and the motion of the shaft 31 changes to the external gear 32. transmitted to At this time, the external gear 32 is regulated in a shape along the outer peripheral surface of the vibrating body 31a, and bends in an elliptical shape when viewed from the axial direction. Furthermore, since the external gear 32 meshes with the fixed first internal gear 33G at its longitudinal portion, it does not rotate at the same rotational speed as the vibrating body 31a. The vibration generator 31a rotates relatively. Along with this relative rotation, the external gear 32 is flexurally deformed so that the major axis position and the minor axis position move in the circumferential direction. The period of this deformation is proportional to the rotation period of the vibrating body 31a.
When the external gear 32 is flexurally deformed, the position of the long axis moves, and thus the meshing position between the external gear 32 (eg, 100 teeth) and the first internal gear 33G (eg, 102 teeth). changes in the direction of rotation, and the external gear 32 rotates according to the difference in the number of teeth between the external gear 32 and the first internal gear 33G. On the other hand, since the external gear 32 also meshes with the second internal gear 34G, the rotation of the vibrating body 31a also changes the meshing position between the external gear 32 and the second internal gear 34G in the rotational direction. Here, if the number of teeth of the second internal gear 34G and the number of teeth of the external gear 32 are the same, the external gear 32 and the second internal gear 34G do not rotate relatively, Rotational motion of gear 32 is transmitted to second internal gear 34G at a reduction ratio of 1:1. With these, the rotational motion of the vibrating body 31a is reduced at a reduction ratio corresponding to the number of teeth of the external gear 32 and the first internal gear 33G, and the internal gear member 34, the output members 38a and 38b, and the output shaft 11 and this rotational motion is output to the driven member.
During transmission of this rotary motion, the rotation of the rotary shaft 21 is detected by the input side rotation detector 51 and the rotation of the output shaft 11 is detected by the output side rotation detector 52 .

When stopping the rotating device 1 , the rotation of the rotating shaft 21 is stopped by controlling the motor 20 . After the rotation of the rotating shaft 21 stops, the electromagnetic coil 44 of the brake 40 is switched from the energized state to the non-energized state. By this switching, instead of the magnetic force of the electromagnetic coil 44, the biasing force of the spring (not shown) operates the armature 43, and the rotor 42 is sandwiched to hold the rotating shaft 21 in a stopped state.

[Dry brake torque measurement test]
In dry brakes such as the brake 40 of the present embodiment, it is common general knowledge for those skilled in the art not to allow lubricant to enter the friction surfaces (contact surfaces) in order to prevent a decrease in holding (braking) torque.
In this regard, the present inventors overturned the above common technical knowledge and found that a desired holding torque can be obtained even when a lubricant penetrates into the friction surface of a dry brake. Specifically, a test was conducted to measure the change in holding torque with and without lubricant on the friction surface, and the torque performance was verified in the presence of lubricant.

Explain the outline of the test.
As shown in FIG. 3( a ), a testing device was used in which a torque meter and a handle were coaxially connected to the rotating shaft 21 of the brake 40 . The output side (electromagnetic coil 44 side) of the brake 40 was fixed to the flange.
In the test, torque was manually applied to the rotating shaft 21 via the handle, and the peak torque immediately before the rotating shaft 21 started to slide was measured as the holding torque. FIG. 3(b) shows an example of the torque waveform during measurement. Torque measurement was performed when no lubricant (grease) was applied to any of the friction materials 43a and 46a (no lubricant), and when it was applied only to the movable friction material 43a on the electromagnetic coil 44 side (lubricant applied - applied to one side). ), and the case where both friction materials 43a and 46a were coated (with lubricant-both sides coated). Assuming a situation in which the lubricant leaked from the speed reducer 30, approximately half of the specified amount of lubricant to be enclosed in the speed reducer 30 was applied to the surface of the friction material.

The test results are shown in FIG. The results show the following.
・When lubricant is applied to only one friction material (with lubricant - applied on one side), holding torque (brake holding torque) is higher than when lubricant is not applied to any friction material (no lubricant). drops to about 68%.
・When lubricant is applied to both friction materials (with lubricant - double-sided application), the holding torque is reduced to about 64% compared to when lubricant is not applied to either friction material (no lubricant). .
・When lubricant is applied to both friction materials (with lubricant - double-sided application), holding torque decreases by 10 compared to when lubricant is applied to only one friction material (with lubricant - single-sided application). %.
・Both of the two patterns in which lubricant is applied to the friction material provide a holding torque equal to or higher than the design allowable lower limit torque.

Thus, even when the lubricant enters the brake 40 from the lubricant-filled space S1 (reduction gear 30) and adheres to the friction surface of the brake 40, the desired holding torque can be obtained. I understand.
The desired holding torque is preferably 50% or more, more preferably 60% or more, of the holding torque when no lubricant is applied to any friction material (no lubricant). This is because dry brake design (design as common general knowledge before the filing of the application) is usually designed to have a holding torque that is about twice the allowable lower limit torque. Further, the degree of decrease in holding torque when lubricant adheres can be adjusted by appropriately setting the material, surface roughness, size (contact area), etc. of the rotor and friction material.

[Technical effect of the present embodiment]
As described above, according to the rotating device 1 of the present embodiment, the lubricant can be circulated between the lubricant enclosure space S1 in which the lubricant is enclosed and the brake accommodation space S2 in which the dry brake is accommodated. communicates with
Conventionally, a contact or non-contact seal is provided between the lubricant enclosure space S1 to prevent the lubricant from entering the dry brake, but the desired torque performance can be achieved without providing such a seal. is obtained. In other words, desired torque performance can be obtained without incurring power loss due to contact seals and structural complication due to non-contact seals. In other words, the present inventors have found that even if a lubricant penetrates into a dry brake, the holding torque does not decrease to the degree that was thought to be common knowledge in the prior art, and the holding torque can be maintained at or above the allowable lower limit torque.
Therefore, a dry brake can be preferably used with a simple configuration. As a result, it is possible to reduce the size, weight, and cost of the device.

Further, according to the rotating device 1 of the present embodiment, the first radial gap G1 between the rotor 42 and the rotating shaft 21 extends from the lubricant-filled space S1 to the lubricant-filled space S1 side of the two friction materials. is smaller than the minimum second radial gap G2 up to the movable friction member 43a.
Therefore, even if the lubricant enters the brake storage space S2 from the lubricant enclosing space S1, the lubricant relatively easily reaches the movable friction member 43a on the output side, and the fixed friction member on the counter-output side. It is relatively difficult for lubricant to reach 46a. Therefore, even if lubricant enters (adheres to) one friction material 43a, it is possible to suppress the lubricant from entering the other friction material 46a. force) can be suppressed.

Further, according to the rotating device 1 of the present embodiment, the electromagnetic coil 44 is arranged closer to the lubricant enclosed space S1 (output side) than the two friction members 43a and 46a.
As a result, the distance from the lubricant-filled space S1 side to the friction material is increased by the electromagnetic coil 44 and its peripheral members, and the risk of the lubricant entering (attaching to) the friction material can be reduced.

[others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.
For example, in the above embodiment, the space inside the speed reducer was described as an example of the lubricant-filled space S1. However, the lubricant enclosing space according to the present invention may be any space that accommodates at least a portion of the rotating shaft and encloses the lubricant, and is not limited to the space within the speed reducer. broadly includes Also, for example, it can be applied to a storage space for a traction mechanism or an internal space for an oil bath motor.
In addition, the lubricant enclosing space and the brake housing space need only be communicated without a seal so that the lubricant can flow therethrough, and there are no particular restrictions on the specific configuration such as the parts arranged there and the distance therebetween.

Further, in the above embodiment, the brake 40 (dry brake) is a holding brake. However, the dry brake according to the present invention is not limited to a holding brake, and may be a braking brake (including emergency braking such as motor failure).
Further, the connection mode between the rotor 42 and the rotating shaft 21 in the brake 40 is not limited to the spline connection, and the first radial gap G1 therebetween is the movable friction material on the side of the lubricant-sealed space S1 from the lubricant-sealed space S1. It may be smaller than the minimum second radial gap G2 up to 43a.

In addition, the details shown in the above embodiment, such as the presence or absence of components other than the lubricant-filled space S1 and the brake 40 in the rotating device 1, the type of the speed reducer 30, etc., can be changed as appropriate without departing from the gist of the invention. .

1 rotating device 11 output shaft 20 motor 21 rotating shaft 30 speed reducer 31 vibrating body shaft 35 first cover 37a first bearing 40 brake (dry brake)
41 hub member 42 rotor 43 armature 43a movable friction material (first friction material)
44 electromagnetic coil (brake coil member)
46 plate 46a fixed friction material (second friction material)
47 Frame 48 Brake casing 50 Rotation detector 60 Circuit part Ax Central axis G1 First radial gap G2 Second radial gap S1 Lubricant enclosing space S2 Brake housing space

Claims (9)

a rotating shaft, a lubricant enclosing space accommodating at least a portion of the rotating shaft and enclosing a lubricant, a dry brake for braking or holding the rotation of the rotating shaft, and a brake accommodating space for accommodating the dry brake , wherein
Lubricant is communicated between the lubricant enclosing space and the brake housing space,
rotating device. the dry brake is a holding brake;
A rotating device according to claim 1 . the lubricant enclosing space and the brake housing space are axially adjacent to each other,
The rotating device according to claim 1 or 2. further comprising a motor;
The brake housing space is arranged between the motor and the lubricant enclosing space,
A rotating device according to claim 3 . The dry brake has a rotor that rotates integrally with the rotating shaft, and two friction materials that are arranged on both sides in the axial direction of the rotor.
The rotation device according to any one of claims 1 to 4. The radial clearance between the rotor and the rotating shaft is the minimum radial clearance in a route from the lubricant-sealed space to the first friction material of the two friction materials, which is located on the lubricant-sealed space side. smaller than the gap
A rotating device according to claim 5 . The dry brake has an armature that sandwiches and presses one of the two friction materials with the rotor, and a brake coil member that attracts the armature,
The brake coil member is arranged closer to the lubricant enclosing space than the two friction materials are.
The rotating device according to claim 5 or 6. In the dry brake, when the lubricant adheres to only one of the two friction materials, the brake torque is increased by 50 compared to the case where neither of the two friction materials adheres to the lubricant. is greater than or equal to
The rotation device according to any one of claims 5 to 7. In the dry brake, when the lubricant adheres to both of the two friction materials, compared to the case where only one of the two friction materials adheres to the lubricant, the brake torque decreases by 10%. is within
The rotating device according to any one of claims 5 to 8.

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