WO2024042727A1

WO2024042727A1 - Actuator

Info

Publication number: WO2024042727A1
Application number: PCT/JP2022/032280
Authority: WO
Inventors: 秀俊植松
Original assignee: ファナック株式会社
Priority date: 2022-08-26
Filing date: 2022-08-26
Publication date: 2024-02-29

Abstract

An actuator (1) comprises a motor (5) and an encoder unit (40). A hollow shaft (23) of the motor (5) includes, between a rotating disk (41) of the encoder unit (40) and the motor (5), an enlarged portion (23A, 23B) for enlarging the thickness thereof. The inner diameter of the hollow shaft (23) is larger than the inner diameter of the enlarged portion (23A, 23B). The rotating disk (41) is fixed to the enlarged portion by a rotating disk fixing portion (35).

Description

actuator

The present disclosure relates to an actuator.

In an actuator including a servo motor, various filaments, such as cables for supplying power, signals, or materials, pass inside the hollow shaft of the rotor of the servo motor and are gripped at both ends of the actuator. Similarly, in an actuator in which a reducer and a servo motor are connected, the low-speed pipe extending from the output shaft of the reducer may pass inside the hollow shaft of the servo motor's rotor (for example, Japanese Patent Laid-Open No. 2017-203645 reference). In such cases, the various filaments pass inside the slow tube and are gripped at both ends of the actuator. In order to reduce the risk of the striatum breaking due to twisting, the striatum is gripped with slack.

Japanese Patent Application Publication No. 2017-203645

In order to allow a large number of filament bodies to pass inside the actuator, it is preferable that the hollow shaft and/or the low-speed tube have a large inner diameter. However, since the thickness of the hollow shaft is reduced, it becomes difficult to screw the rotary disk of the encoder into the thickness of the hollow shaft.

Therefore, an actuator that can easily connect the rotary disk of the encoder to the end face of the hollow shaft is desired.

According to a first aspect of the present disclosure, the motor includes a rotor with a hollow shaft, and an encoder unit with a rotating disk, and between the rotating disk and the motor, the hollow shaft is , the hollow shaft includes an expanded portion whose thickness expands, the inner diameter of the hollow shaft is larger than the inner diameter of the expanded portion, and the rotating disk is fixed to the expanded portion of the hollow shaft by a plurality of screws. An actuator is provided.

Objects, features, and advantages of the present disclosure will become more apparent from the following description of embodiments in conjunction with the accompanying drawings.

FIG. 3 is an axial cross-sectional view of the actuator according to the first embodiment. FIG. 3 is a front view of the encoder fixing section. FIG. 2 is another axial cross-sectional view of the actuator shown in FIG. 1; FIG. 3 is an axial cross-sectional view of an actuator according to a second embodiment. FIG. 7 is an axial cross-sectional view of an actuator according to a third embodiment. FIG. 7 is an axial cross-sectional view of an actuator according to a fourth embodiment. FIG. 7 is an axial cross-sectional view of an actuator according to an additional embodiment.

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. Corresponding components are given common reference numerals throughout the drawings.
FIG. 1 is an axial cross-sectional view of an actuator according to the first embodiment. The actuator 1 shown in FIG. 1 mainly includes a motor 5, such as a servo motor, consisting of a stator 10 and a rotor 20, and an encoder 40 connected to the motor 5. The encoder 40 including the rotating disk 41 is, for example, an incremental encoder, and outputs A-phase, B-phase, and Z-phase signals. Encoder 40 may be an optical encoder or a magnetic encoder.

The stator 10 includes a stator core 11 fixed within a housing 12 by a key 15. Stator core 11 includes a plurality of coils 13 arranged around the central axis of motor 5 .

The rotor 20 is rotatably arranged inside the stator core 11. The rotor 20 includes a rotor core 21 in which a plurality of magnets 22, for example, permanent magnets, are arranged on the outer peripheral surface, and a hollow shaft 23 that rotates integrally with the rotor core 21 on the central axis of the motor 5. The hollow shaft 23 is rotatably arranged in the housing 12 via

bearings

51 and 52.

FIG. 2 is a front view of the encoder fixing part. As can be seen from FIGS. 1 and 2, the encoder fixing portion 43 of the encoder 40 is fixed to the housing 12 through the elongated hole 46 with a plurality of second screws 45. The detection unit 42 provided on the substrate 49 of the encoder 40 detects the absolute position PA1 within one rotation of the hollow shaft 23 and the total number of rotations PB1 using a known method. The detected information is stored in memory (not shown), for example volatile memory.

As shown in FIG. 1, the hollow shaft 23 includes an expanded portion 23A whose thickness expands toward the inside in the radial direction of the hollow shaft 23 between the rotating disk 41 and the motor 5. The expanded portion 23A is formed at one end of the hollow shaft 23 on the encoder 40 side. Due to the presence of such an expanded portion 23A, the inner diameter D1 of the hollow shaft 23 is larger than the inner diameter D2 of the expanded portion 23A. In one embodiment, (D1-D2)/D1 is preferably between 0.1 and 0.2. The length and thickness of the expanded portion 23A in the axial direction of the hollow shaft 23 are large enough to receive a rotating disk fixing portion 35, which will be described later.

In FIG. 1, the rotating disk 41 of the encoder 40 is fixed to the end surface of the extended portion 23A by the rotating disk fixing part 35. Typically, the rotating disk fixing portion 35 is formed on the end surface of the expanded portion 23A to correspond to a plurality of first screws 35 extending parallel to the axial direction of the hollow shaft 23 and the plurality of first screws 35. This is a combination of multiple holes. However, other forms of the rotating disk fixing part 35 that can fix the rotating disk 41 to the extended portion 23A may be used.

Therefore, in the first embodiment, the rotating disk 41 of the encoder 40 can be easily connected to the end surface of the hollow shaft 23. Note that the number of the plurality of first screws 35 and the number of the plurality of holes may be different, and the plurality of first screws 35 may not be arranged at equal intervals in the circumferential direction of the hollow shaft 23.

FIG. 3 is another axial cross-sectional view of the actuator shown in FIG. 1. In FIG. 3, at least one filament C, for example a cable supplying power, signals or materials, passes through the actuator 1 through the interior space of the hollow shaft 23. In FIG. At least one filament C is fixed near both ends of the actuator 1 by fixing parts (not shown in FIGS. 1 and 3).

As can be seen from FIGS. 1 and 3, the thickness of the expanded portion 23A is sufficiently smaller than the inner diameter of the hollow shaft 23, so even if the expanded portion 23A is formed, there is no need to reduce the number of striatal bodies C. The slack of the striatum C may be maintained.

Strictly speaking, in FIGS. 1 and 3, the rotary disk 41 is fixed to the end surface of the extended portion 23A via the boss 25 by a plurality of first screws 35. Preferably, the boss 25 is attached to the rotating disk 41 by adhesive or the like. Note that the rotating disk 41 may be directly fixed to the end surface of the extended portion 23A. In this case, the rotary disk 41 of the encoder can be connected to the hollow shaft 23 more easily.

By the way, FIG. 4 is an axial cross-sectional view of an actuator based on another embodiment. The actuator 1a in another embodiment has an expanded portion 23B whose thickness expands toward the outside in the radial direction of the hollow shaft 23 between the rotating disk 41 and the motor 5 instead of the expanded portion 23A. As shown in FIG. 4, the inner diameter D1 of the hollow shaft 23 is equal to the inner diameter D2' of the expanded portion 23B. In other words, even if the expanded portion 23B is formed, the inner diameter of the hollow shaft 23 does not change throughout the hollow shaft 23. The rotating disk 41 of the encoder 40 is fixed to the end surface of the expanded portion 23B by a plurality of first screws 35 extending parallel to the axial direction of the hollow shaft 23.

In this case, since the inner diameter of the expanded portion 23B is equal to the inner diameter of the other portions of the hollow shaft 23, one or more filaments C can be inserted into the hollow shaft with more margin than in the embodiment shown in FIG. 23 will be passed through. Further, as described above, a case where the rotary disk 41 is directly fixed to the end surface of the extended portion 23B without using the boss 25 is also included in the scope of the present disclosure. Furthermore, a case where both the expanded portion 23A and the expanded portion 23B are formed at one end of the hollow shaft 23 is also included in the scope of the present disclosure.

FIG. 5 is an axial cross-sectional view of the actuator according to the third embodiment. The actuator 1b shown in FIG. 5 mainly includes a motor 5, such as a servo motor, including a stator 10 and a rotor 20, an encoder 40 connected to the motor 5, and a speed reducer 30 connected to the motor 5. Note that another encoder (not shown) may be connected to the reducer 30. The motor 5 and encoder 40 are generally the same as those described above, so a repeated explanation will be omitted.

A low-speed pipe 31 connected to the output shaft 32 of the reducer 30 extends toward the motor 5 through the internal space of the hollow shaft 23. The hollow shaft 23 and the low speed tube 31 of the reducer 30 are arranged coaxially with each other. As mentioned above, the hollow shaft 23 of the rotor 20 is provided with an enlarged portion 23A. The low-speed pipe 31 of the speed reducer 30 is provided with a stepped portion 33 immediately before the expanded portion 23A.

A portion of the low-speed tube 31 located closer to the encoder 40 than the stepped portion 33 is bent to correspond to the expanded portion 23A. That is, the inner diameter D3' of the portion of the low-speed tube 31 is smaller than the inner diameter D3 of the low-speed tube 31. As can be seen from FIG. 5, the low-speed tube 31 extends beyond the expanded portion 23A of the hollow shaft 23 and passes through the encoder 40.

At least one filament C is fixed near both ends of the actuator 1 by fixing

parts

61 and 62. In FIG. 5, one fixed part 61 is arranged inside the rotary disk 41 on the encoder 40 side, specifically in the internal space of the low-speed tube 31, and the other fixed part 62 is arranged in a hollow space on the reducer 30 side. It is arranged in the internal space of the shaft 23.

These fixing

parts

61 and 62 correct the center position of at least one filament body C within the hollow shaft 23 and/or the low-speed tube 31, and prevent the bundle of filament bodies C from expanding excessively due to slack. play a role in prevention. Furthermore, the fixing

parts

61, 62 serve to avoid contact between the inner wall of the hollow shaft 23 and/or the low-speed tube 31 and the at least one filament body C.

As can be seen from FIG. 5, the length of the stepped portion 33 in the radial direction of the hollow shaft 23 is sufficiently smaller than the outer diameter of the hollow shaft 23, so even if the expanded portion 23A and the stepped portion 33 are formed, the filament There is no need to reduce the number of bodies C, and the sagging of these striatal bodies C may be maintained. Therefore, it will be understood that even if the actuator 1b is equipped with the reducer 30, substantially the same effects as described above can be obtained.

FIG. 6 is an axial cross-sectional view of the actuator according to the fourth embodiment. Similarly, the actuator 1c shown in FIG. Included in

In the fourth embodiment, the low-speed tube 31 does not include the stepped portion 33, and the low-speed tube 31 terminates before the expanded portion 23A of the hollow shaft 23. With such a configuration, in the fourth embodiment, there is no need to prepare the low-speed tube 31 having the stepped portion 33, and it is also possible to further increase the thickness of the expanded portion 23A. Therefore, it can be seen that the rotary disk 41 can be easily fixed to the expanded portion 23A of the hollow shaft 23 by the plurality of first screws 35.

Further, in the fourth embodiment, a tube member 50 is provided that extends at least partially toward the rotating disk 41 from a position corresponding to the expanded portion 23A. Tubing 50 extends at least partially through encoder 40 . Preferably, the tube 50 does not move relative to the fixed part 61. Therefore, the tube 50 serves to prevent at least one filament C from contacting the inner wall of the encoder 40 and the expanded portion 23A of the hollow shaft 23. This makes it possible to protect the encoder 40 and the like.

As shown in FIG. 6, the tube 50 may be attached to the encoder 40 via a flange 51 provided at one end of the tube 50. Alternatively, the outer peripheral surface of the tube 50 may be attached to the encoder 40. Therefore, it becomes easy to attach the tube material 50 to the encoder 40. It will be understood that in the fourth embodiment, even if the actuator 1c is equipped with the reducer 30, substantially the same effects as those described above can be obtained.

FIG. 7 is an axial cross-sectional view of an actuator according to an additional embodiment, and is generally similar to FIG. 1. In the embodiment described above, the plurality of first screws 35 are arranged parallel to the axial direction of the hollow shaft 23. In contrast, in FIG. 7, a plurality of first screws 35 are arranged in the radial direction of the hollow shaft 23. A plurality of holes extending in the radial direction of the hollow shaft 23 and corresponding to the first screws 35 are formed on the outer peripheral surface of the expanded portion 23A.

In other words, the rotating disk fixing part 35 in the additional embodiment includes a plurality of first screws 35 extending in a radial direction with respect to the axial direction of the hollow shaft 23, and an expanded portion 23A that corresponds to the plurality of first screws 35. This is a combination of multiple holes formed on the outer circumferential surface.

When fixing the rotary disk 41 to the hollow shaft 23 via the boss 25 using such a first screw 35, the first screw 35 can be approached to the boss 25 from the outside in the radial direction of the hollow shaft 23. It will be seen that the work of fixing the rotating disk 41 becomes easier.

The cross section of the boss 25 shown in FIG. 7 is approximately L-shaped, and the boss 25 includes an abutting portion that abuts the outer peripheral surface of the expanded portion 23A. The plurality of first screws 35 are engaged with the expanded portion 23A via the abutting portions of the bosses 25 mentioned above. Note that the boss 25 and the rotating disk 41 are fixed to each other with, for example, adhesive.

Therefore, in additional embodiments in which a plurality of first screws 35 are arranged in the radial direction of the hollow shaft 23, the boss 25 needs to include an abutment portion. In other words, in embodiments other than the additional embodiment shown in FIG. 7, it is also possible to eliminate the boss 25 and connect the rotating disk 41 and the extension portion 23A directly.

Note that in an additional embodiment, the boss 25 may include an abutting portion that abuts the inner circumferential surface of the expanded portion 23A. That is, the contact portion of the boss 25 may be arranged inside the expanded portion 23A. Furthermore, some of the plurality of first screws 35 are arranged parallel to the axial direction of the hollow shaft 23, and the remaining first screws 35 are arranged radially with respect to the hollow shaft 23. Good too. Even such cases are included within the scope of the present disclosure.

In either embodiment, the rotary disk 41 of the encoder 40 is easily connected to the end face of the hollow shaft 23 without the need to reduce the number of striae C and while maintaining the slack of the striae C. be able to.

Aspects of the Present Disclosure According to a first aspect, the rotor includes a motor including a rotor with a hollow shaft, and an encoder unit with a rotating disk, and the hollow shaft is connected between the rotating disk and the motor. includes an expanded portion whose thickness expands, the inner diameter of the hollow shaft is larger than the inner diameter of the expanded portion, and the rotating disk is attached to the expanded portion of the hollow shaft by a rotating disk fixing part. An actuator is provided, which is fixed.
According to a second aspect, the first aspect further includes a speed reducer coupled to the other end of the hollow shaft, and a low speed pipe connected to the output shaft of the speed reducer, and the low speed pipe extends inside the hollow shaft toward the encoder unit and terminates before the expanded portion.
According to a third aspect, the apparatus according to the first or second aspect further includes a tube member extending at least partially toward the rotating disk from a position corresponding to the expanded portion.
According to a fourth aspect, the first aspect further includes a reducer coupled to the other end of the hollow shaft, and a low speed pipe coupled to the output shaft of the reducer, and the low speed pipe extends at least partially inside the hollow shaft towards the encoder unit, and the low speed tube has a step corresponding to the enlarged portion of the hollow shaft.
According to a fifth aspect, in any one of the first to fourth aspects, the rotating disk fixing part extends in parallel to the axial direction of the hollow shaft or extends in the radial direction of the hollow shaft. Multiple screws.

Effects of Aspects In the first aspect, the rotary disk of the encoder can be easily connected to the end face of the hollow shaft without the need to reduce the number of striatal bodies and while maintaining the slack of the striatal bodies. can.
In the second embodiment, it is not necessary to provide a low-speed tube with a stepped portion, and it is also possible to further increase the thickness of the expanded portion.
In a third embodiment, it serves to prevent the at least one filament from contacting the inner wall of the encoder and the enlarged portion of the hollow shaft.
In the fourth aspect, even if the actuator is equipped with a speed reducer, the rotary disk of the encoder can be easily connected to the end surface of the hollow shaft.
In a fifth aspect, when the first screw extends in the radial direction of the hollow shaft, the work of fixing the rotating disk is facilitated. When the first screw extends parallel to the axial direction of the hollow shaft, the size of the expanded portion can be minimized, and the strength of fixing the rotating disk can be increased.

Although the embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the individual embodiments described above. These embodiments are subject to various additions, substitutions, and changes without departing from the gist of the invention or the spirit and spirit of the present invention derived from the contents described in the claims and equivalents thereof. , partial deletion, etc. are possible. For example, in the embodiments described above, the order of each operation and the order of each process are shown as examples, and are not limited to these. Further, the same applies when numerical values or formulas are used in the description of the embodiments described above. Furthermore, it is within the scope of the present disclosure to appropriately combine some of the embodiments described above.

1, 1a to 1c Actuator 5 Motor 10 Stator 11 Stator core 12 Housing 13 Coil 20 Rotor 21 Rotor core 22 Magnet 23

Hollow shaft

23A, 23B Expanded portion 25 Boss 30 Reducer 31 Low speed tube 32 Output shaft 35 First screw (rotating disk fixing part )
40 Encoder 41 Rotating disk 42 Detection section 43 Encoder fixing section 46 Long hole 49

Substrate

51, 52

Bearing

61, 62 Fixing section C Wiring body

Claims

a motor including a rotor with a hollow shaft;
an encoder unit with a rotating disk;
Between the rotating disk and the motor, the hollow shaft includes an expanded portion whose thickness expands;
The inner diameter of the hollow shaft is larger than the inner diameter of the expanded portion,
The actuator, wherein the rotating disk is fixed to the expanded portion of the hollow shaft by a rotating disk fixing part.
a speed reducer coupled to the other end of the hollow shaft;
further comprising a low speed pipe connected to the output shaft of the reducer,
2. The actuator of claim 1, wherein the low speed tube extends inside the hollow shaft towards the encoder unit and terminates before the expansion.
The actuator according to claim 1 or 2, further comprising a tube extending at least partially toward the rotating disk from a position corresponding to the expanded portion.
a speed reducer coupled to the other end of the hollow shaft;
further comprising a low speed pipe connected to the output shaft of the reducer,
the low speed tube extends at least partially inside the hollow shaft towards the encoder unit;
The actuator according to claim 1, wherein the low speed tube has a step corresponding to the expanded portion of the hollow shaft.
The actuator according to any one of claims 1 to 4, wherein the rotating disk fixing part is a plurality of screws extending parallel to an axial direction of the hollow shaft or extending in a radial direction of the hollow shaft. .