Actuator

Abstract

Provided is a technique for ascertaining the lubrication state of a contact unit in an actuator provided with a motor and a speed reducer. An actuator (10) provided with a motor and a speed reducer, the actuator (10) being provided with: a contact unit (60A) comprising a plurality of contact members and in which adjacent contact members come into contact with each other in accordance with relative movement during operation of the actuator; a plurality of energizing members (66A, 66B) that are provided separately from the contact unit (60A) and that cause a current to flow through an energizing path that is configured from the plurality of actuator-constituting members via contact points between the plurality of contact members; and a measurement unit (62) that measures the lubrication state between the plurality of contact members in the contact unit (60A) by causing a current to flow through the conduction path.

Description

actuator

[0001] This application claims priority based on Japanese Patent Application No. 2024-192442, filed on October 31, 2024. The entire contents of that Japanese application are incorporated herein by reference. Technical Field

[0002] This disclosure relates to an actuator. Background Technology

[0003] Patent document 1 discloses an actuator comprising a motor and a reducer. This actuator typically includes a contact unit consisting of multiple contact components such as bearings and gear sets. Within this contact unit, adjacent contact components can contact each other as they move relative to each other during actuator operation.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2022-142033

[0005] The lubrication condition between the contact components of the actuator's contact unit during operation affects various factors such as the actuator's lifespan, thus requiring precise control over this lubrication condition. However, for actuators incorporating both a motor and a reducer, no technology has yet been proposed that can meet this requirement. Summary of the Invention

[0006] Therefore, one of the objectives of this disclosure is to provide a technique for monitoring the lubrication status of contact units in an actuator that includes a motor and a speed reducer.

[0007] The actuator disclosed herein is an actuator having a motor and a reducer, comprising: a contact unit consisting of a plurality of contact members, wherein adjacent contact members contact each other as they move relative to each other during operation of the actuator; a plurality of energizing members disposed separately from the contact unit and used to allow current to flow through an energizing path, the energizing path being formed by a plurality of actuator constituent components via contact portions between the plurality of contact members; and a measuring unit for measuring the lubrication state between the plurality of contact members in the contact unit by allowing current to flow through the energizing path.

[0008] Invention Effects

[0009] According to this disclosure, in an actuator equipped with a motor and a reducer, the lubrication status of the contact unit can be monitored. Attached Figure Description

[0010] Figure 1 is a side sectional view of the actuator according to an embodiment.

[0011] Figure 2 is a magnified view of a portion of Figure 1.

[0012] Figure 3 is a block diagram illustrating a portion of the functionality of the actuator in the embodiment.

[0013] In the diagram: 10-actuator, 14-motor, 16-reducer, 26-stator, 28-rotor, 52-rotating body, 56A, 56B-relative rotating bodies, 60A~60F-contact unit, 60H-measurement object unit, 62-measuring section, 64-power path, 66A-first power-on component, 66B-second power-on component, 76-life prediction section. Detailed Implementation

[0014] The following describes embodiments of the actuator used to implement this disclosure. Identical or equivalent elements are labeled with the same reference numerals, and repeated descriptions are omitted. In the figures, for ease of explanation, constituent elements are appropriately omitted, enlarged, or reduced. The figures should be viewed according to the direction of the symbols. In this specification, the expressions "first," "second," etc., "nth" (where n is a natural number) are used only as a formal way of distinguishing multiple elements and have no other substantial meaning. For example, the order of the elements labeled "nth" is not limited. Furthermore, the elements labeled "nth" may exist independently without being sequential. For example, this means that even if the "first" element does not exist, the "second" element may still exist.

[0015] Referring to Figure 1, the actuator 10 is capable of driving a driven device (not shown) by outputting rotation. The driven device is configured as at least one of the following: (1) industrial machinery such as machine tools and construction machinery, (2) robots such as industrial robots and service robots, (3) handling equipment such as conveyors, and (4) various machines such as vehicles. The actuator 10 is an integrated actuator that integrates the motor housing 24 and the reducer housing 34 described later.

[0016] The actuator 10 includes: a motor 14 having a motor body 12; and a reducer 16 for reducing the rotation output from the motor body 12. Furthermore, as an optional configuration, the actuator 10 also includes: a load-opposite housing 18 disposed on the load-opposite side of the motor housing 24 of the motor 14; and a circuit board 20 fixed to the load-opposite housing 18. Hereinafter, the direction along the rotation center line L22 of the motor shaft 22 of the motor 14 will be simply referred to as the axial direction, and the radial direction and circumferential direction of the circle centered on the rotation center line L22 will be simply referred to as the radial and circumferential directions. Furthermore, the side axially from the motor 14 toward the reducer 16 (left side of the paper in FIG1) will be called the load side, and the side axially opposite to it (right side of the paper in FIG1) will be called the load-opposite side.

[0017] In addition to the motor body 12, the motor 14 also includes a motor shaft 22 that rotates from the motor body 12 and a motor housing 24 that houses the motor body 12. The motor body 12 includes a stator 26 and a rotor 28. The stator 26 is disposed within the inner periphery of the motor housing 24 and is fixed to the motor housing 24 by means of interference fit, bonding, or other methods. The type of stator 26 is not particularly limited; for example, it can be a permanent magnet stator, a wound stator, or a coreless stator. The rotor 28 is configured to rotate integrally with the motor shaft 22, for example, by means of interference fit, bonding, or other methods. The type of rotor 28 is not particularly limited; for example, it can be a permanent magnet rotor, a cage rotor, a wound rotor, or a coreless rotor. The motor housing 24 houses the motor body 12 and the motor shaft 22, among other things.

[0018] The speed reducer 16 includes: an input shaft 30 for inputting rotational energy output from the motor body 12; a speed reduction mechanism 32 for reducing the rotational speed of the input shaft 30; a speed reducer housing 34 for housing at least a portion of the speed reduction mechanism 32; and a load-side cover 36 disposed on the load side of the speed reduction mechanism 32. In this embodiment, the speed reduction mechanism 32 is a gear mechanism having an external gear 38 and internal gears 40A and 40B meshing with each other. The speed reducer 16 in this embodiment is a cylindrical flexure meshing speed reducer. The speed reduction mechanism 32 in this speed reducer causes the external gear 38 to flex and deform via a vibrating element 44 provided on the input shaft 30, thereby causing one of the external gear 38 and internal gears 40A and 40B (in this case, the external gear 38) to rotate, and its rotational component can be output via an output member 42. Since the operating principle of this speed reducer is well known, its description is omitted here. In the cylindrical form, the reduction mechanism 32 has a first internal gear 40A disposed on the opposite side of the load and a second internal gear 40B disposed on the load side as internal gears 40A and 40B. The output component 42 takes out the rotation reduced by the reduction mechanism 32 and outputs it to the outside. In this embodiment, the output component 42 is constituted by the load-side cover 36. Alternatively, instead of the load-side cover 36, the output component 42 may also be constituted by the reducer housing 34.

[0019] In this embodiment, the input shaft 30 is configured to rotate integrally with the motor shaft 22. The input shaft 30 in this embodiment includes a vibrating element 44 that causes the external gear 38 to flex. The cross-sectional shape of the outer periphery of the vibrating element 44, orthogonal to the axial direction, is elliptical. Here, "elliptical" is not limited to a strictly geometrically elliptical shape, but also includes approximately elliptical shapes.

[0020] In this embodiment, the external gear 38 is a flexible cylindrical component that flexes and deforms as the vibrator 44 rotates. The internal gears 40A and 40B in this embodiment are cylindrical components with sufficient rigidity to prevent flexing and deformation as the vibrator 44 rotates. The first internal gear 40A meshes with the external teeth of the load-opposite portion of the external gear 38, and the second internal gear 40B meshes with the external teeth of the load-side portion of the external gear 38. The first internal gear 40A has a different number of teeth than the external gear 38 (e.g., 102), and the second internal gear 40B has the same number of teeth as the external gear 38.

[0021] The reducer housing 34 is disposed on the load side of the motor housing 24. Besides housing at least a portion of the reduction mechanism 32 (here, the external gear 38), the reducer housing 34 also houses the input shaft 30, the load-side cover 36, etc. In this embodiment, the reducer housing 34 is composed of multiple reducer housing components connected by bolts or the like. In this embodiment, the reducer housing 34 also serves as the first internal gear 40A. In this embodiment, a main bearing 46 is disposed between the reducer housing 34 and the second internal gear 40B, and an oil seal 48 made of an electrically insulating material such as resin is also disposed there. The load-side cover 36 is connected to the second internal gear 40B by bolts or the like.

[0022] A vibrating body bearing 50 is disposed between the vibrating body 44 and the external gear 38 to support the external gear 38 for free rotation. In this embodiment, two vibrating body bearings 50 arranged axially are disposed between the vibrating body 44 and the external gear 38. The vibrating body bearing 50 of this embodiment includes: a plurality of rolling elements 50a; an outer ring 50b and an inner ring 50c, in which the rolling elements 50a roll; and a cage 50d for holding the plurality of rolling elements 50a. The rolling elements 50a of this embodiment are shown as rollers, but there is no limitation on the specific examples, and various rolling elements such as balls can be used. The outer ring 50b of the vibrating body bearing 50 of this embodiment also serves as the inner circumference of the external gear 38, but a dedicated outer ring 50b may also be provided. The inner ring 50c of the vibrating body bearing 50 of this embodiment also serves as the outer circumference of the vibrating body 44, but a dedicated inner ring 50c may also be provided.

[0023] The load-opposite housing 18 of this embodiment includes: an annular first load-opposite housing component 18a, which is fixed to the load-opposite end of the motor housing 24 by a threaded structure or the like; and a second load-opposite housing component 18b, disposed on the load-opposite side of the first load-opposite housing component 18a. The second load-opposite housing component 18b is connected to the first load-opposite housing component 18a by bolts or the like. The circuit board 20 is disposed inside the second load-opposite housing component 18b and is fixed to the second load-opposite housing component 18b by threads or the like.

[0024] The actuator 10 includes a rotating body 52 that rotates via a stator 26 and a rotor 28. In this embodiment, the rotating body 52 is composed of a motor shaft 22 and an input shaft 30.

[0025] The actuator 10 includes a first rotation sensor 54A for detecting information related to the rotation of the rotating body 52. ​​In this embodiment, the first rotation sensor 54A is configured as a rotary encoder, but it can also be configured as a resolver or the like. Here, "information related to rotation" refers to speed, phase, torque, etc. The first rotation sensor 54A includes: a detection unit 54a, configured to rotate integrally with the rotating body 52; and a detection unit 54b, opposite to the detection unit 54a and mounted on the circuit board 20. The detection unit 54a is configured, for example, using a scale such as an optical scale or a magnetic scale. The detection unit 54b is configured, for example, using an optical sensor or a magnetic sensor. The detection unit 54b can detect information related to the rotation of the rotating body 52 by detecting changes in predetermined physical quantities (light intensity, magnetic field, etc.) generated as the detection unit 54a rotates.

[0026] Refer to Figure 2. In this figure, for ease of explanation, cross-sectional lines are omitted except for electrically insulating components. The actuator 10 described above includes relative rotating bodies 56A and 56B that rotate relative to the rotating body 52. ​​The relative rotating bodies 56A and 56B include: a first relative rotating body 56A, which includes a motor housing 24; and a second relative rotating body 56B, which includes a load-side cover 36 of the reducer 16.

[0027] The first relative rotating body 56A in this embodiment is composed of a motor housing 24, a reducer housing 34, a load-opposite side housing 18, a circuit board 20, etc. The second relative rotating body 56B in this embodiment is composed of a load-side cover 36, a second internal gear 40B, etc. In this embodiment, the rotating body 52 functions as a high-speed rotating body that rotates at a relatively high speed. Furthermore, in this embodiment, the relative rotating body including the output component 42 in the first relative rotating body 56A and the second relative rotating body 56B (here, the second relative rotating body 56B) functions as a low-speed rotating body that rotates at a relatively low speed.

[0028] The actuator 10 described above includes: a first rotating body bearing 58A, disposed between a first opposing rotating body 56A and a rotating body 52; and a second rotating body bearing 58B, disposed between a second opposing rotating body 56B and a rotating body 52. ​​Each rotating body bearing 58A and 58B supports the rotating body 52. ​​In this embodiment, the first rotating body bearing 58A is disposed between the motor housing 24, which is part of the first opposing rotating body 56A, and the rotating body 52, and the second rotating body bearing 58B is disposed between the load-side cover 36, which is part of the second opposing rotating body 56B, and the rotating body 52.

[0029] The actuator 10 includes contact units 60A to 60F, which are composed of a plurality of contact members. In contact units 60A to 60F, adjacent contact members come into contact with each other as they move relative to each other during operation of the actuator 10. This means that during operation of the actuator 10, adjacent contact members make at least one of sliding contact and rolling contact with each other.

[0030] The contact units 60A to 60F in this embodiment include: contact units 60A to 60D, which are composed of bearings; and contact units 60E and 60F, which are composed of gear sets. In this embodiment, the contact units composed of bearings include: a first contact unit 60A, which is composed of a vibrating body bearing 50; a second contact unit 60B, which is composed of a first rotating body bearing 58A; a third contact unit 60C, which is composed of a second rotating body bearing 58B; and a fourth contact unit 60D, which is composed of a main bearing 46. In this embodiment, the contact units 60E and 60F composed of gear sets include a fifth contact unit 60E composed of an external gear 38 and a first internal gear 40A, and a sixth contact unit 60F composed of an external gear 38 and a second internal gear 40B.

[0031] Contact units 60A to 60D, which are composed of bearings, include rolling elements, an outer ring, and an inner ring, serving as multiple contact components. In this configuration, adjacent outer rings and rolling elements contact each other as they move relative to each other, and adjacent rolling elements and inner rings also contact each other as they move relative to each other. Thus, the combination of the outer ring and rolling elements and the combination of the rolling elements and inner rings primarily involve rolling contact.

[0032] Contact units 60E and 60F, composed of gear sets, include external gears 38 and internal gears 40A and 40B, serving as multiple contact components. Adjacent external gears 38 and internal gears 40A and 40B come into contact as they move relative to each other. The external gears 38 and internal gears 40A and 40B then contact in a contact pattern corresponding to the type of reducer 16. As in this embodiment, when a flexural reducer is used as the reducer 16, the external gears 38 and internal gears 40A and 40B primarily engage in sliding contact.

[0033] The actuator 10 is provided with a receiving space 61 for accommodating lubricant used to lubricate these contact units 60A to 60F. The lubricant is such as grease or lubricating oil. The lubricant lubricates the contact points between the multiple contact components of the contact units 60A to 60F. The receiving space 61 can be sealed by a sealing component such as an oil seal 48.

[0034] The actuator 10 of this embodiment is characterized by having a measuring unit 62 for measuring the lubrication state of at least a portion of the contact units 60A to 60F. The measuring unit 62 of this embodiment measures the lubrication state of the first contact unit 60A. Before describing this detailed structure, the underlying concept will first be explained.

[0035] In contact unit 60A, the contact portion between adjacent contact components is called the contact area. Depending on the lubrication state of contact unit 60A, the contact area of ​​contact unit 60A may contain portions where the contact components are in direct contact with each other and portions where the contact components are in contact with each other via a lubricant. The lubrication state of contact unit 60A can be divided into three states: boundary lubrication, where the contact components are in direct contact throughout the entire contact area; hydrodynamic lubrication, where the contact components are in contact with each other via a lubricant film throughout the entire contact area; and mixed lubrication, which is an intermediate state between boundary lubrication and hydrodynamic lubrication. In mixed lubrication, the contact area contains portions where the contact components are in direct contact with each other and portions where the contact components are in contact with each other via a lubricant. Regarding the lubrication state, when the relative speed of adjacent contact components is slow, it is called boundary lubrication; as the relative speed increases, it successively changes to mixed lubrication and hydrodynamic lubrication.

[0036] In the contact area of ​​contact unit 60A, the portions of the contact components that contact each other via lubricant function like capacitors, while the portions of the contact components that directly contact each other function like resistors. Here, the lubricant film thickness and the metal contact ratio α are known parameters representing the lubrication state of contact unit 60A. The oil film thickness refers to the thickness of the lubricant between adjacent contact components. The metal contact ratio α is the ratio of the area of ​​the directly contacting portions of the contact components to the total contact area between the contact components. In this case, in the portions of the contact components that contact each other via lubricant, similar to the distance between the electrodes of a capacitor, the electrical characteristics of contact unit 60A change depending on the thickness of the lubricant film present therebetween. Furthermore, as the metal contact ratio α decreases, the proportion of portions that act like capacitors increases, and correspondingly, the electrical characteristics in the contact area of ​​contact unit 60A change. That is, the electrical characteristics in the contact area of ​​contact unit 60A change depending on the lubrication state of contact unit 60A (e.g., oil film thickness, metal contact ratio α). This means that the lubrication status of the contact unit 60A can be measured by flowing current through the energized path 64 via the contact area of ​​the contact unit 60A and measuring its response.

[0037] For example, if the oil film thickness in the contact area of ​​contact unit 60A increases, the electrostatic capacitance of contact unit 60A decreases accordingly, and the impedance of the current-carrying path 64 through contact unit 60A tends to increase. Therefore, by applying an AC voltage to the current-carrying path 64 through the contact area of ​​contact unit 60A to allow AC current to flow, and by measuring the magnitude Z of the complex impedance of the current-carrying path 64, the oil film thickness of contact unit 60A can be measured. Furthermore, when AC current flows through the current-carrying path 64 through the contact area of ​​contact unit 60A, since contact unit 60A acts as a capacitor, a phase shift occurs between the voltage and current values ​​of the AC current. As the metal contact ratio α of contact unit 60A decreases, and the proportion of the portion in its contact area that acts as a capacitor increases, the magnitude of this phase shift tends to increase. Therefore, when AC current flows through the current-carrying path 64 through the contact area of ​​contact unit 60A, the metal contact ratio α of contact unit 60A can be measured by measuring the phase difference of the complex impedance of the current-carrying path 64. The measuring unit 62 of the actuator 10 measures the lubrication state of the contact unit 60A based on this concept. Its detailed structure will be further explained below.

[0038] The actuator 10 is provided with an energizing path 64 composed of multiple actuator components. In FIG2, for ease of explanation, a portion of the energizing path 64 is marked with a single-dot dashed line. The actuator components refer to the components that constitute the actuator 10. Among the multiple actuator components constituting the energizing path 64, at least a first contact unit 60A (vibrator bearing 50) that is the object of measurement of the measuring unit 62 is included. In addition, the multiple actuator components in this embodiment also include an external gear 38, internal gears 40A and 40B, a rotating body 52, a first relative rotating body 56A (reducer housing 34, motor housing 24), a second relative rotating body 56B (second internal gear 40B), a main bearing 46, etc. The multiple actuator components constituting the energizing path 64 are made of a conductive material. This conductive material is, for example, a metallic material such as an iron-based material or an aluminum-based material, but is not limited to these; it may also be a conductive resin-based material.

[0039] The energizing path 64 is a path through which current can flow between a first terminal 64a, defined by the first energizing member 66A (described later), and a second terminal 64b, defined by the second energizing member 66B. The first terminal 64a is the location where the first energizing member 66A inputs or outputs current, and the second terminal 64b is the location where the second energizing member 66B inputs or outputs current. In this embodiment, the first terminal 64a is provided on the rotating body 52, and the second terminal 64b is provided on the first relative rotating body 56A.

[0040] The energizing path 64 is configured to pass through contact portions between multiple contact members of the contact unit 60A, which is the object of measurement. In this embodiment, the contact unit 60A, which is the object of measurement, is a bearing, and the energizing path 64 is configured, for example, to pass through contact portions between the rolling element 50a and the outer ring 50b, and contact portions between the rolling element 50a and the inner ring 50c. The energizing path 64 in this embodiment includes: an intermediate path portion 64c, which passes through the contact unit 60A, which is the object of measurement; a first end-side path portion 64d, which is located on the first end 64a side of the intermediate path portion 64c and connected to the first end 64a; and a second end-side path portion 64e, which is located on the second end 64b side of the intermediate path portion 64c and connected to the second end 64b. In this embodiment, the intermediate path portion 64c is provided separately for each of the two contact units 60A, and the separate intermediate path portions 64c are connected in parallel between the first end-side path portion 64d and the second end-side path portion 64e. The first end-side path portion 64d of this embodiment is connected to the rotating body 52. ​​The second end-side path portion 64e of this embodiment is connected to the motor housing 24, the reducer housing 34, the first internal gear 40A, the second internal gear 40B, and the external gear 38.

[0041] The actuator 10 includes a plurality of energizing components 66A and 66B for allowing current to flow through the energizing path 64. The plurality of energizing components 66A and 66B are disposed separately from the contact unit 60A. The plurality of energizing components 66A and 66B include a first energizing component 66A and a second energizing component 66B. The first energizing component 66A is used to input current to or output current from the rotating body 52 where the first end 64a of the energizing path 64 is located. The second energizing component 66B is used to input current to or output current from the first relative rotating body 56A where the second end 64b of the energizing path 64 is located. In this embodiment, the first energizing component 66A serves as a current input component for inputting current into the energizing path 64, and the second energizing component 66B serves as a current output component for outputting current from the energizing path 64. Alternatively, the first energized component 66A can be used as a current output component, and the second energized component 66B can be used as a current input component. The first energized component 66A and the second energized component 66B are electrically connected to the measuring unit 62 via wiring components (not shown), connectors, or the like. In this embodiment, the measuring unit 62 is mounted on the circuit board 20, but for ease of explanation, the figure shows the measuring unit 62 located separately from the circuit board 20. Alternatively, the measuring unit 62 can also be provided separately from the circuit board 20.

[0042] In this embodiment, the first energizing component 66A is composed of a brush that slides on the rotating body 52. ​​When it serves as a current input component, the first energizing component 66A can be composed of a coil that induces current in the rotating body 52. ​​The same applies when the second energizing component 66B serves as a current input component. In this embodiment, the first energizing component 66A is disposed on the load-opposite side of the stator 26 of the motor 14. The first energizing component 66A is disposed at a position that overlaps axially with the internal space of the motor housing 24. The first energizing component 66A can be directly or via other components fixed to the load-opposite side housing 18. Alternatively, both the first energizing component 66A and the detection portion 54b of the first rotation sensor 54A are supported on the load-opposite side housing 18.

[0043] The second energizing component 66B in this embodiment is composed of an electrode fixed to the first relative rotating body 56A. The second energizing component 66B in this embodiment is fixed to the outer periphery of the motor housing 24 constituting the first relative rotating body 56A. Alternatively, the second energizing component 66B may be fixed to the housing 18 on the opposite side of the load, the motor housing 24, etc. In this embodiment, the second energizing component 66B6 is disposed on the opposite side of the stator 2 of the motor 14. Alternatively, the second energizing component 66B can be disposed on the portion opposite to the load of the first relative rotating body 56A.

[0044] Furthermore, the rotational speed of the rotating body 52 (high-speed rotating body) located at the front end of the reduction mechanism 32 of the reducer 16 is generally much faster than the rotational speed of the contact units 60E and 60F (gear sets) or the first and second relative rotating bodies 56A and 56B constituting the reduction mechanism 32. Therefore, in the contact units 60A to 60C arranged between the rotating body 52 and other components, the relative speed of adjacent contact components becomes very fast. As a result, the lubrication state of the contact units 60A to 60C is generally a mixed lubrication state or a fluid lubrication state, and the oil film thickness and metal-to-metal contact ratio α change over time. In contrast, the relative speed of adjacent contact components in the contact unit 60D (main bearing) arranged between the first and second relative rotating bodies 56A and 56B, or in the contact units 60E and 60F (gear sets) constituting the reduction mechanism 32, is generally very slow compared to the contact units 60A to 60C. Therefore, the lubrication state of these contact units 60D to 60F is usually almost unchanged over time under boundary lubrication conditions where the oil film thickness is zero.

[0045] In this embodiment, the change in the lubrication state of contact unit 60A among the plurality of contact units 60A, 60D to 60F is measured using the current flowing through the energizing path 64 (described later) via the plurality of contact units 60A, 60D to 60F. At this time, the influence of contact units 60D to 60F, whose lubrication state hardly changes, on the current flowing through the energizing path 64 becomes very small compared to the influence of contact units 60A, whose lubrication state changes. Therefore, the influence of contact units 60D to 60F, whose lubrication state does not change, can be ignored. In other words, the measuring unit 62 of this embodiment only measures the lubrication state of contact units 60A, 60D to 60F located on the energizing path 64, which are arranged between the rotating body 52, which functions as a high-speed rotating body, and other components. The contact unit 60A that will be measured by this measuring unit 62 is called the measurement target unit 60H. In this embodiment, the measurement target unit 60H is the first contact unit 60A (vibrator bearing 50). Thus, the measurement unit 60H in this embodiment constitutes part of the reducer 16. The measurement unit 60H in this embodiment is disposed on the load side of the stator 26. In addition, the measurement unit 62 can also compensate for the fluctuations in the current flowing through the energized path 64 caused by the contact units 60D to 60F, whose lubrication state hardly changes, through calibration.

[0046] Refer to Figure 3. Each functional module consists of a combination of hardware and software, or either hardware or software alone. These functional modules can be implemented in various ways through their collaboration. Each functional module can be implemented using common or different hardware or software.

[0047] In addition to the first rotation sensor 54A described above, the actuator 10 also includes a second rotation sensor 54B for detecting information related to the rotation of the output component 42, and a control device 70 for controlling the actuator 10. The second rotation sensor 54B is composed of a rotary encoder, a rotary transformer, etc.

[0048] In addition to the measuring unit 62 described above, the control device 70 also includes a motor control unit 72, a storage unit 74, and a lifespan prediction unit 76 (described later). The hardware of the control device 70 utilizes, for example, a processor, ROM (Read Only Memory), or RAM (Random Access Memory). The hardware of the control device 70 may be comprised of, for example, a processing chip mounted on the circuit board 20. The software of the control device 70 utilizes, for example, an operating system, applications, or other programs. The storage unit 74 stores data used in the processing performed by the control device 70.

[0049] The motor control unit 72 controls the operation of the motor 14. For example, the motor control unit 72 controls the motor 14 so that the speed or torque-related detection values ​​detected by the rotation sensors 54A and 54B are close to the command values ​​sent from an external control device. The control content of the motor control unit 72 is just one example and is not limited thereto.

[0050] The measuring unit 62 measures the lubrication state (hereinafter, simply referred to as the lubrication state of the contact unit) between multiple contact components of the contact unit 60A by allowing current to flow through the aforementioned energized path 64 via the contact unit 60A. To achieve this, the measuring unit 62 only needs to measure at least one parameter representing the lubrication state of the contact unit 60A. This parameter may be, for example, the oil film thickness of the lubricant, the metal-to-metal contact ratio α, etc. The measuring unit 62 of this embodiment will be described as an example of a method for measuring the lubrication state of the contact unit 60A using the impedance method. As described above, the method involves simultaneously measuring the oil film thickness and the metal-to-metal contact ratio α by allowing alternating current to flow through the energized path 64 and measuring the magnitude Z (in Ω) and phase difference θ (in rad) of the complex impedance of the energized path. The measuring unit 62 may be configured using, for example, an LCR meter or similar instrument capable of measuring these parameters.

[0051] When measuring the lubrication state of contact unit 60A, a predetermined relationship (hereinafter also referred to as the measurement value-lubrication state relationship) between the measured value related to the current flowing through the energized path 64 and the lubrication state of contact unit 60A is stored in storage unit 74. In this embodiment, the measured value related to the current is the magnitude Z of the complex impedance and the phase difference θ described above. These relationships are stored in the form of formulas described later in this embodiment, but are not limited to this; they may also be stored in the form of data tables or the like. The measuring unit 62 calculates parameters representing the lubrication state of contact unit 60A (here, oil film thickness and metal contact ratio α) based on the measured value related to the current flowing through the energized path 64 using the relationship stored in storage unit 74, thereby measuring the lubrication state.

[0052] Next, an example of a relational expression representing the relationship between the measured value and the lubrication state will be explained. This relational expression can be any of the known expressions. Regarding this relational expression, in the case of measuring the lubrication state of the contact unit 60A composed of bearings using the impedance method, it can be determined, for example, by the various expressions (1) to (6) explained below.

[0053] [Formula 1]

[0054]

[0055] [Equation 2]

[0056]

[0057] [Formula 3]

[0058]

[0059] [Formula 4]

[0060]

[0061] [Formula 5]

[0062]

[0063] [Formula 6]

[0064] W(z′)·exp(W(z′))=z′…(6)

[0065] The meanings of the various markings in equation (1) are as follows. l (unit is dimensionless) represents the number of contact areas for each rolling element. In this embodiment, the rolling element 50a forms contact areas with both the outer ring 50b and the inner ring 50c, therefore l is 2. R 10 (Unit: Ω) represents the resistance of the contact area when it is in an oil-free state (when the metal contact ratio α is 1). k (unit: dimensionless) represents the number of contact units 60A (bearings) connected in parallel in the energizing path 64 that are the objects of measurement. In this embodiment, the number of contact units 60A that are the objects of measurement is two, so k is 2. n (unit: dimensionless) represents the number of rolling elements 50a used in the bearing.

[0066] The meanings of the various symbols in equation (2) are as follows. h1 (in meters) is the oil film thickness in the contact area of ​​contact unit 60A, and is one of the parameters to be measured in this embodiment. δ (in meters) can be represented by equation (3). ψ (dimensionless) can be represented by equation (4). r h (Unit: m) refers to r, which will be discussed later. x and r y The average value of ζ (in Ω) can be expressed by equation (5). W is a Lambert function and is defined by equation (6). z' in equation (6) is an arbitrary complex number.

[0067] The meanings of various markings in equation (3) are as follows: a (in meters) represents the average major axis of the contact ellipse of each contact area (the contact area between rolling element 50a and outer ring 50b, and the contact area between rolling element 50a and inner ring 50c) of contact unit 60A when they approximate a contact ellipse. b (in meters) represents the average minor axis of the contact ellipse of each contact area of ​​contact unit 60A when they approximate a contact ellipse. r x (Unit: m) represents the average of the equivalent radius of curvature between rolling element 50a and outer ring 50b and between rolling element 50a and inner ring 50c in the rolling direction of rolling element 50a. y (Unit: m) represents the average of the equivalent radius of curvature between rolling element 50a and outer ring 50b, and between rolling element 50a and inner ring 50c, in a direction perpendicular to the rolling direction of rolling element 50a. b (in meters) is the radius of the rolling element 50a. These are known values, determined based on the geometric conditions such as the shape and position of the rolling element 50a, outer ring 50b, and inner ring 50c of the contact unit 60A. ε (in F / m) is the dielectric constant of the lubricant. ω (in rad / s) is the frequency of the AC voltage applied to the energized path 64, and is determined as a set value (known value).

[0068] When using equations (1) to (6), l and R can be... 10 ,k,n,a,b,r x r y r h r b ε and ω are stored in the storage unit 74 as predetermined known values ​​and used. In other words, the relationship between the measured value related to the current flowing through the energized path 64 and the lubrication state of the contact unit 60A is determined by the geometric conditions of the contact unit 60A, the characteristic value of the lubricant (dielectric constant), and the set value (ω) related to the current flowing through the energized path 64. As the measured value related to the current flowing through the energized path 64, the magnitude of the complex impedance Z and the phase difference θ of the energized path 64 are used. Using these, the oil film thickness h1 and the metal contact ratio α are calculated according to equations (1) to (6), and the calculated values ​​are used as the measurement results. The oil film thickness h1 and the metal contact ratio α calculated here are the average values ​​of the oil film thickness and the metal contact ratio α in all contact areas of the first contact unit 60A (vibrator bearing 50). In the case where there are multiple contact units 60A connected in parallel in the energized path 64 that are the objects of measurement, it is the average value related to multiple contact units 60A.

[0069] The effects of the actuator 10 described above will be explained. The actuator 10 includes a measuring unit 62, which measures the lubrication state of the contact unit 60A by allowing current to flow through the energized path. Therefore, the lubrication state of the contact unit 60A can be determined using the measurement results of the measuring unit 62.

[0070] The oil film thickness, which indicates the lubrication state of contact unit 60A, sometimes depends on the torque acting on contact unit 60A. Therefore, the torque can also be measured using the oil film thickness measurement.

[0071] The first energizing component 66A is disposed on the load-opposite side of the stator 26 of the motor 14. It is easier to secure space around the rotating body 52 on the load-opposite side of the stator 26 than on the load side of the stator 26. By disposing the first energizing component 66A at such a location, the actuator 10 can be mounted without significantly altering its existing design.

[0072] The contact unit 60A, which is the object of measurement, is disposed on the load side of the stator 26. At this time, if the first energizing member 66A is to be disposed around the contact unit 60A, which is the object of measurement, and around the rotating body 52, space is difficult to secure at that location, thus requiring a significant change to the existing actuator 10 design. In this respect, according to this embodiment, as described above, the first energizing member 66A is disposed on the opposite side of the load side of the stator 26, where space is easily secured. Therefore, even when the contact unit 60A, which is the object of measurement, is disposed on the load side of the stator 26, the first energizing member 66A can be installed in the actuator 10 without significantly changing the existing actuator 10 design.

[0073] The second energizing component 66B is disposed on the load-opposite side of the stator 26 of the motor 14. The space around the first relative rotating body 56A is more easily secured on the load-opposite side of the stator 26 than on the load side of the stator 26. By disposing the second energizing component 66B at such a location, the actuator 10 can be mounted without significantly altering its existing design.

[0074] The contact unit 60A, which is the object of measurement, is part of the reducer 16. Therefore, the lubrication status of the contact unit 60A, which is part of the reducer 16, can be determined using the measurement results of the measuring unit 62.

[0075] Other features of the actuator 10 will be described. Refer to FIG2. Hereinafter, the contact unit 60A, which will be the object of measurement in the lubricated state, will be referred to as the object of measurement 60H. A parallel path 80 is provided in the actuator 10, which is connected in parallel with the object of measurement 60H in the energized path 64, assuming that it is conductive. The parallel path 80 is composed of at least one actuator component and is connected in parallel with the object of measurement 60A and 60B between the first end-side path portion 64d and the second end-side path portion 64e. Here, "assuming that it is conductive" means assuming that all actuator components located on the parallel path 80 are conductive. In this embodiment, the parallel path 80 is provided separately for the second contact unit 60B (first rotating body bearing 58A) and the third contact unit 60C (second rotating body bearing 58B), and is provided via contact portions between multiple contact components of the corresponding contact units 60C and 60D.

[0076] Multiple contact units 60A to 60F include a non-measuring object unit 60I disposed on such a parallel path 80. The non-measuring object unit 60I is not a measuring object of the lubrication state of the measuring unit 62. In this embodiment, the non-measuring object unit 60I is respectively composed of a second contact unit 60B and a third contact unit 60C.

[0077] The actuator 10 includes an insulating material 82 that prevents current from flowing through the parallel paths 80 on the energized path 64. The insulating material 82 is individually provided for each parallel path 80. Therefore, when current flows through the energized path 64 through the measurement target unit 60H, the insulating material 82 prevents the current from passing through the non-measurement target unit 60I. Thus, when measuring the lubrication state of the measurement target unit 60H by measuring the response of the current through the measurement target unit 60H, erroneous measurements due to current passing through the non-measurement target unit 60I can be prevented.

[0078] In this embodiment, the insulating material 82 is composed of at least a portion of the non-measuring object unit 60I. Specifically, the outer rings of the first rotating body bearing 58A and the second rotating body bearing 58B constituting the non-measuring object unit 60I in this embodiment are composed of electrically insulating materials such as ceramics or resins. A portion of this electrically insulating material constitutes the insulating material 82. While an example of electrically insulating outer rings has been described here, at least one or all of the rolling elements, outer rings, and inner rings may also be composed of insulating materials. In other words, a portion or all of the non-measuring object unit 60I constitutes the insulating material 82. Therefore, compared to separating the insulating material 82 from the non-measuring object unit 60I, the structure can be simplified.

[0079] Furthermore, when the bearing, such as the vibrator bearing 50, is the measurement object unit 60H, in order to measure the lubrication state at the contact points between the outer ring 50b and the rolling element 50a, and between the rolling element 50a and the inner ring 50c, a current path 64 needs to be provided that simultaneously passes through these two contact points. Therefore, it is necessary to prevent the current from flowing to other parts via the rolling element 50a and the cage 50d instead of passing through these two contact points. To achieve this, in this embodiment, the cage 50d of the vibrator bearing 50 is made of a material with electrical insulation properties.

[0080] Referring to Figure 3, the lubrication condition of the contact unit 60A affects the lifespan of the actuator 10. In particular, the lubrication condition of the oscillating bearing 50 used in the flexural gear reducer has a very significant impact on the lifespan of the actuator 10. This is because the oscillating bearing 50 is subjected to a large load, and the lubrication condition is under harsh conditions due to the high-speed rotation of the rotating body 52. ​​The same applies to the eccentric bearing used in the eccentric oscillating gear reducer. This eccentric bearing is positioned between the eccentric portion of the crankshaft and the oscillating gear that oscillates through the eccentric portion. Hereinafter, an example of a method for predicting the lifespan of the actuator 10 using measured values ​​of parameters related to the lubrication condition of the contact unit 60A, which consists of such an oscillating bearing 50, will be described.

[0081] The life prediction unit 76 predicts the life of the actuator 10 based on the lubrication state of the contact unit 60A (in this embodiment, the vibrating bearing 50) measured by the measuring unit 62. When predicting the life of the actuator 10, a predetermined relationship (hereinafter also referred to as the lubrication state-life relationship) between the lubrication state of the contact unit 60A and the life of the actuator 10 is stored in the storage unit 74. These relationships are stored in the form of formulas in this embodiment, but are not limited to this; they may also be stored in the form of data tables, etc. The life prediction unit 76 calculates the life of the actuator 10 based on the measured values ​​of parameters representing the lubrication state of the contact unit 60A using the relationships stored in the storage unit 74, and predicts the life of the actuator 10.

[0082] The frequency at which the lifespan prediction unit 76 predicts the lifespan of the actuator 10 is not particularly limited. For example, the lifespan prediction unit 76 can predict the lifespan of the actuator 10 once, triggered by a command sent from an external control device. Furthermore, the lifespan prediction unit 76 can predict the lifespan of the actuator 10 at predetermined time intervals. Therefore, even if the lifespan is affected by annual changes in the operation of the actuator 10, the latest lifespan of the actuator 10 can be predicted taking this effect into account. Moreover, the lifespan prediction unit 76 can predict the lifespan of the actuator 10 sequentially during its operation and monitor the sequentially obtained prediction values ​​during the operation of the actuator 10. Furthermore, the lifespan prediction unit 76 can calculate the remaining time from the current moment until the end of the lifespan based on the predicted lifespan of the actuator 10, and display this remaining time on a display device such as a monitor (not shown).

[0083] Next, an example of a relational expression representing the lubrication state-life relationship will be explained. This relational expression can be obtained using various expressions, including those that are already known. This relational expression is determined, for example, by the various equations (7) to (12) explained below.

[0084] [Formula 7]

[0085]

[0086] [Formula 8]

[0087]

[0088] [Formula 9]

[0089]

[0090] [Formula 10]

[0091]

[0092] [Equation 11]

[0093] κ(t)≈Λ 1.3 …(11)

[0094] [Equation 12]

[0095]

[0096] The meanings of the various symbols in equation (7) are as follows. L 10 (in time) represents the basic rated lifespan of actuator 10. L1 (in time) is the rated lifespan predetermined according to the type of actuator 10, for example, 7,000, 10,000, etc. T OE (Unit: N·m) represents the rated torque (N·m) output from the output component 42 of the actuator 10. rated (Unit: rpm) represents the rated speed output from the output component 42 of actuator 10, i.e., the rated speed. Rated torque T OE Rated speed n rated All are predetermined based on the type of actuator 10.

[0097] n EI (Unit: rpm) represents the time-averaged rotational speed of the motor shaft 22 of the actuator 10 during operation in a specific operating mode, i.e., the average input speed. This operating mode is, for example, an operating mode specified by an external control device. The motor control unit 72 controls the motor 14, causing the actuator to operate in a cyclical manner that repeats this operating mode. Thus, the average input speed n... EI Determined based on the operating mode used for actuator 10.

[0098] T in equation (7) E (Unit: N·m) represents the torque exerted on the output component 42 by the actuator 10 under a specific operating mode, i.e., the equivalent torque. This equivalent torque T is known. E For example, it can be obtained according to equation (8).

[0099] The meanings of the various symbols in equation (8) are as follows. T(t) and n(t) are the torque and speed of the output component 42 at any time t, respectively. ISO (t) represents the lifetime correction factor at any time t. The lifetime correction factor a ISO This is a coefficient used to reflect the influence of various factors on the basic rated life. These various factors include: the contamination coefficient e, which reflects the influence of lubricant contamination. c(Unitless) The fatigue limit load C is the load acting on the vibrating bearing 50 when the maximum load contact portion is applied to the track surface of the vibrating bearing 50. u (Unit: N), and the viscosity ratio κ(t) of the lubricant at any time t. Life correction factor a ISO ISO 281:2007, JIS B1518, and other standards also stipulate that it can be expressed as a function of various elements, such as equation (9). Pollution coefficient e c Fatigue limit load C u It can be calculated based on the contents recorded in ISO 281, JIS B1518, etc., and is predetermined. In equation (9), P is the dynamic equivalent load (in N) of the vibrating bearing 50. It is known that using the above-mentioned T(t) and T... OE This is expressed by equation (10). C in equation (10) r The dynamic radial rated load (in N) of the vibrating body bearing 50 can be determined in advance.

[0100] The viscosity ratio κ(t) of the lubricant, as described in ISO 281:2007, JIS B1518, etc., can be estimated, for example, using the oil film parameter Λ (unitless) by equation (11). The known oil film parameter Λ can be obtained, for example, by equation (12). In equation (12), h0 is the oil film thickness of the lubricant at any time t (in μm), and R1 and R2 are the surface roughness of the contacting parts (in μm). For example, when determining the oil film parameter Λ of the vibrating bearing 50, the measured values ​​of the surface roughness of the rolling element 50a and the outer ring 50b are used as known values, or the measured values ​​of the surface roughness of the rolling element 50a and the inner ring 50c are used as known values.

[0101] When using equations (7) to (12) above, the torque T(t) and rotational speed n(t) at any time t in equation (8), etc., are obtained by using the torque and rotational speed detected successively by the output component 42 by the rotation sensor 54B. The viscosity ratio κ(t) of the lubricant in equation (9) is obtained by using the measured value of the oil film thickness of the contact unit 60A measured by the measuring unit 62 at any time t. Other values ​​are obtained by using known values ​​pre-stored in the storage unit 74. The basic rated life L is calculated by using these equations. 10 The lifespan of actuator 10, which reflects the oil film thickness of contact unit 60A, is estimated.

[0102] As described above, the actuator 10 includes a life prediction unit 76, which predicts the life of the actuator 10 based on the measured lubrication state of the contact unit 60A. Therefore, the life of the actuator 10 can be predicted considering the lubrication state of the contact unit 60A. By predicting the life of the actuator 10 in this way, the timing of maintenance, replacement, etc., of the actuator 10 can be determined. This facilitates predictive maintenance of the actuator 10 and helps minimize the downtime of the actuator 10.

[0103] If we focus on n in equation (7) EI Therefore, it can be said that the lubrication state-life relationship stored in the storage unit 74 is determined at least by the operating mode of the actuator 10. It can also be said that the life prediction unit 76 predicts the life of the actuator 10 based on the lubrication state-life relationship determined by such an operating mode. Therefore, it is possible to predict the life of the actuator 10 under a specific operating mode while taking into account the lubrication state of the contact unit 60A.

[0104] Next, variations of the above-mentioned constituent elements will be explained.

[0105] The specific locations of the multiple energized components 66A and 66B are not particularly limited, as long as they form an energizing path 64 via the contact unit that is the object of measurement. For example, the first energized component 66A can be disposed on the load side of the stator 26 or at a position that overlaps with the stator 26 radially. For example, the second energized component 66B can be disposed on the load side of the stator 26 or at a position that overlaps with the stator 26 radially.

[0106] The specific example of the contact unit (measurement object unit 60H) that becomes the measurement object of the measuring unit 62 is not limited to the vibrating bearing 50, and can be various contact units used for the actuator 10. The measurement object unit 60H can be, for example, a gear set. Thus, when the measurement object unit 60H is set as a gear set, the specific example of the reducer 16 is not particularly limited. The reducer 16 can be, for example, an eccentric oscillating reducer (including center crank type, distribution type), a flexural meshing reducer (including cylindrical type, top hat type, cup type), a simple planetary reducer, an orthogonal shaft reducer, a parallel shaft reducer, etc., in addition to eccentric oscillating reducers (including center crank type, distribution type), and flexural meshing reducers (including cylindrical type, top hat type, cup type). Furthermore, the reduction mechanism of the reducer 16 is not limited to a gear mechanism, and can also be a friction transmission mechanism, etc. In this case, the measurement object unit 60H can be a friction transmission group composed of multiple friction transmission components (contact components), which transmit power through friction transmission. Furthermore, the measurement object unit 60H can also be an eccentric bearing of an eccentric oscillating reducer. The eccentric bearing mentioned here refers, for example, to the bearing described in Japanese Patent Application Publication No. 2022-79015. In this case, as described above, it has the same advantage as when the vibrator bearing 50 is set as the measurement target unit 60H, in that it is possible to grasp the lubrication state of the eccentric bearing, which has a significant impact on the lifespan of the actuator 10. The measurement target unit 60H can be arranged on the opposite side of the load on the stator 26.

[0107] When various contact units are used as measurement objects, the positions of multiple energized components 66A and 66B can be changed according to the position of the contact unit being measured, so as to form an energizing path 64 via the contact unit being measured. In this embodiment, an example in which other contact units also exist on the energizing path 64 via the contact unit being measured is described. Otherwise, there may be no other contact units on the energizing path 64 via the contact unit being measured. Furthermore, multiple measurement object units 60H connected in series may exist on the energizing path 64. The measurement object unit 60H may not be part of the reducer 16. For example, the measurement object unit 60H may be part of the motor 14.

[0108] The above describes an example of measuring the lubrication state of a contact unit by using the resistance method, where alternating current flows through the energized path 64 of the contact unit. The method for measuring the lubrication state of the contact unit by the measuring unit 62 is not particularly limited. For example, the resistance method or the capacitance method can be used. In the case of the resistance method, a weak direct current flows through the energized path by applying a direct current voltage to the measuring unit 62, and the resistance value of the contact unit is measured based on this direct current, thereby allowing the oil film thickness to be measured based on the resistance value. In the case of the capacitance method, an alternating current flows through the energized path by applying an alternating current voltage to the measuring unit 62, and the capacitance is measured based on this alternating current, thereby allowing the oil film thickness to be measured based on the measured value of the capacitance. Thus, when measuring the lubrication state of the contact unit by the measuring unit 62, the current flowing through the energized path 64 of the contact unit can be either alternating current or direct current.

[0109] In this embodiment, the measurement-lubrication state relationship is explained when the contact unit is a bearing. Similarly, when the contact unit is a gear set or other type of contact unit, the measurement-lubrication state relationship corresponding to that contact unit can be predetermined. This relationship, like the aforementioned formula, can be determined by at least one of the following: the geometric relationship of the contact unit, the characteristic value of the lubricant, or a set value related to the current flowing through the energized path. When determining this relationship, those skilled in the art can determine an appropriate measurement-lubrication state relationship corresponding to that contact unit through experiments, analysis, etc.

[0110] The actuator 10 may not include the insulating material 82. The insulating material 82 may not be constituted by the non-measuring object unit 60I, but may be provided separately from the non-measuring object unit 60I. For example, the insulating material 82 may constitute at least a part of the actuator component on the parallel path 80 described above. In this case, the insulating material may constitute a part of the actuator component in which the non-measuring object unit 60I is disposed.

[0111] The lubrication condition used by the life prediction unit 76 to predict the life of the actuator 10 is not limited to the lubrication condition of the vibrating body bearing 50. This lubrication condition can be the lubrication condition of the eccentric bearing mentioned above, or it can be the lubrication condition of other contact units.

[0112] Specific examples of parameters representing the lubrication state of the contact unit used for actuator 10 life prediction are not limited to oil film thickness. For example, the phase angle θ of the impedance described above can be used as this parameter. There is a correlation between this phase angle θ and the viscosity ratio κ(t) in equation (9). For example, when the lubrication state becomes fluid lubrication state, the phase angle α reaches its maximum value. Furthermore, as the lubrication state deteriorates from the lubrication state to the mixed lubrication state and the boundary lubrication state, the phase angle θ approaches zero from its maximum value. Regarding the viscosity ratio κ(t), it is also greater than 1 when the lubrication state becomes fluid lubrication state, and decreases to less than 1 as the lubrication state deteriorates. That is, when the phase angle α reaches its maximum value, the viscosity ratio κ(t) is greater than 1, and as the phase angle α approaches zero from its maximum value, the viscosity ratio κ(t) decreases. Using this, the relationship between the phase angle θ and the viscosity ratio κ(t) is pre-stored in the storage unit 74 in the form of a relational formula, etc., and the viscosity ratio κ(t) is calculated based on this relationship and the measured value of the phase angle θ, and this calculated value is used in equation (9).

[0113] The components described in the above embodiments are examples. These abstracted technical concepts should not be interpreted solely within the scope of this specification. The components described in the embodiments can be modified, added to, or deleted in various design changes. For components that can undergo such design changes, the terms "this embodiment" or "implementation" are used to emphasize this. However, this does not mean that design changes are not permitted for components not described in this way. Any combination of the above components is also valid. For example, any description of other embodiments can be combined with an embodiment, or any description of other embodiments can be combined with a variant. The structures and values ​​mentioned in the embodiments and variants naturally include cases where manufacturing errors are considered to be the same. In this specification, a component consisting of one part can also consist of multiple parts. Similarly, a component consisting of multiple parts can also consist of one part.

Claims

1. An actuator comprising a motor and a reducer, the actuator comprising: a contact unit consisting of a plurality of contact members, wherein adjacent contact members contact each other as they move relative to each other during operation of the actuator; a plurality of energizing members disposed separately from the contact unit for allowing current to flow through an energizing path passing through contact portions between the plurality of contact members and comprising a plurality of actuator constituent components; and a measuring unit for measuring the lubrication state between the plurality of contact members in the contact unit by allowing current to flow through the energizing path.

2. The actuator according to claim 1, wherein, The motor has a rotating body that rotates via the stator and rotor. The plurality of energizing components include a first energizing component for inputting current to the rotating body or outputting current from the rotating body. The first energizing component is disposed on the opposite side of the load of the stator.

3. The actuator according to claim 2, wherein, The contact unit, which is the object of measurement of the measuring unit, is disposed on the load side of the stator.

4. The actuator according to claim 3, wherein, The device includes a relative rotating body that rotates relative to the rotating body, and the plurality of energized components include a second energized component for inputting the current to the relative rotating body or outputting the current from the relative rotating body.

5. The actuator according to claim 4, wherein, The second energized component is positioned on the opposite side of the load of the stator.

6. The actuator according to claim 1, wherein, The contact unit includes: a measurement object unit disposed on the energized path and serving as the measurement object of the measuring unit; and a non-measurement object unit disposed on a parallel path connected in parallel with the measurement object unit on the energized path, assuming that the actuator components are conductive, wherein the actuator has an insulating material that prevents current from flowing through the parallel path on the energized path.

7. The actuator according to claim 6, wherein, The insulating material is composed of at least a portion of the non-measuring object unit.

8. The actuator according to claim 1, wherein, The contact unit that is the object of measurement of the measuring unit is a gear set or a bearing.

9. The actuator according to claim 1, wherein, The contact unit, which is the object of measurement of the measuring unit, constitutes part of the speed reducer.

10. The actuator according to claim 1, wherein, The actuator is equipped with a life prediction unit that predicts the life of the actuator based on the lubrication state measured by the measurement unit.

Images