Gear motor

Abstract

Provided is a gear motor capable of reducing the weight of a shaft. A gear motor includes a motor and a speed reducer, wherein the gear motor includes a shaft formed by integrating a rotor shaft that rotates by the driving of the motor and an input shaft of the speed reducer, and the shaft is formed by integrating a resin portion made of a resin material and a metal portion made of a metal material.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2021-035463, filed on March 5, 2021. The entire contents of that Japanese application are incorporated herein by reference. Technical Field

[0002] This invention relates to a gear motor. Background Technology

[0003] Patent document 1 discloses a gear motor that includes a motor and a reducer. The gear motor has a shaft body that is integrated with the rotor shaft, which rotates under the drive of the motor, and the input shaft of the reducer.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-97364

[0005] In the shaft of Patent Document 1, the input shaft and the rotor shaft are integrally formed from metal. The inventors of this application recognize that there is room for improvement in the technology disclosed in Patent Document 1 in terms of achieving a lightweight shaft. Summary of the Invention

[0006] One of the objectives of this invention is to provide a gear motor that can achieve a lightweight shaft.

[0007] The present invention provides a gear motor comprising a motor and a reducer. The gear motor comprises a shaft integrally formed by a rotor shaft that rotates under the drive of the motor and an input shaft of the reducer. The shaft is a structure integrally formed by a resin part made of a resin-based material and a metal part made of a metal-based material.

[0008] According to the present invention, the shaft can be made lighter. Attached Figure Description

[0009] Figure 1 This is a side sectional view of the gear motor according to the first embodiment.

[0010] Figure 2 This is a perspective view showing the shaft and its surrounding structure in the first embodiment.

[0011] Figure 3 This is a side sectional view showing the shaft and its surrounding structure in the first embodiment.

[0012] Figure 4 yes Figure 3 A sectional view cut along line AA.

[0013] Figure 5 From Figure 3 The diagram when observing the axis from direction B.

[0014] Figure 6This is a diagram illustrating the forming method of the shaft body according to the first embodiment.

[0015] In the diagram: 10-Gear motor, 16-Motor, 18-Rotor shaft, 20-Reducer, 22-Shaft body, 26-Detector, 28-Brake, 30, 32, 34-Bearings, 38-Rotor, 42-Input shaft, 78-Rolling element, 84-Detector mounting section, 86-Rotor mounting section, 88-Brake mounting section, 88a-Protrusion, 90, 92, 94-Bearing mounting section, 91-Rolling surface, 100-Shaft body, 102-Input shaft assembly, 104-Resin part, 106-Metal part, 110-Outer cylindrical part, 112-Inner cylindrical part, 114-Metal protrusion, 118-Resin recess. Detailed Implementation

[0016] The embodiments will now be described. Identical components are labeled with the same symbols, and repeated descriptions are omitted. In the accompanying drawings, components are appropriately enlarged or reduced for ease of explanation. The drawings are viewed with respect to the orientation of the symbols.

[0017] refer to Figure 1 A gear motor 10 connects the first object component 12 and the second object component 14. The gear motor 10 is capable of rotating the second object component 14 relative to the first object component 12. In this embodiment, the gear motor 10 is assembled into the joint of an industrial robot. In this embodiment, the first object component 12 and the second object component 14 are either a base component or an arm component of a multi-joint arm.

[0018] The gear motor 10 includes a motor 16, a rotor shaft 18 that rotates under the drive of the motor 16, a reducer 20 that reduces the rotation of the rotor shaft 18, and a shaft body 22 integrally formed by the rotor shaft 18 and the input shaft 42 of the reducer 20. Furthermore, the gear motor 10 also includes a reduction mechanism 44 housing the reducer 20 and a housing 24 housing the motor 16, a detector 26 for detecting the rotation of the shaft body 22, a brake 28 for braking the shaft body 22, and multiple bearings 30, 32, and 34 disposed on the outer periphery of the shaft body 22. The first component 12 is integrally connected to the housing 24 by screws or the like, and the second component 14 is integrally connected to the wheel frame 46 of the reducer 20 by screws or the like.

[0019] Hereinafter, the direction along the rotation center line CL of shaft 22 will be referred to as axial X, and the circumferential direction and radial direction of the circle centered on this rotation center line CL will be referred to as "circumferential" and "radial," respectively. Furthermore, the direction along axial X from the motor 16 towards the reducer 20 ( Figure 1 The left side is called the load side, and the side opposite to it on the axial X-axis ( Figure 1 The right side of the load is called the opposite side of the load.

[0020] The motor 16 includes a stator 36 fixed to a motor housing 60 of the housing 24 and a rotor 38 that rotates integrally with the rotor shaft 18. In this embodiment, the rotor 38 is a permanent magnet rotor. The rotor 38 includes a rotor core 40 composed of a laminate of multiple metal plates 40a (e.g., electromagnetic steel plates) and permanent magnets (not shown) disposed in slots within the rotor core 40. The rotor shaft 18 extends through the motor 16 along the axial direction X.

[0021] The speed reducer 20 includes an input shaft 42 for inputting the rotation of the rotor shaft 18 and a speed reduction mechanism 44 for reducing the rotation of the input shaft 42. In addition, the speed reducer 20 also includes a wheel frame 46 disposed axially on the load side relative to the speed reduction mechanism 44, a speed reducer housing 48 for housing the speed reduction mechanism 44, and an output component 50 for outputting the reduced rotation from the speed reduction mechanism 44.

[0022] The reduction mechanism 44 of this embodiment is a flexural meshing gear mechanism that causes the external gear 52 to flex and deform via the input shaft 42, thereby causing one of the external gear 52 and the internal gear 56 to rotate, and outputs the rotational component via the output member 50. The reduction mechanism 44 of this embodiment is a cylindrical flexural meshing gear mechanism that uses a first internal gear 54 whose relative rotation with respect to the reducer housing 48 is restricted, and a second internal gear 56 that can rotate relative to the reducer housing 48.

[0023] The input shaft 42 includes a gear drive section 58 that drives the gear (external gear 52) of the reduction mechanism 44 when the input shaft 42 rotates. The gear drive section 58 of the input shaft 42, which is used in a flexural meshing type gear mechanism, is elliptical in a section orthogonal to the axial direction X. The gear drive section 58 is positioned to overlap radially with the external gear 52 of the reduction mechanism 44, which is driven.

[0024] The reduction mechanism 44 includes an external gear 52 disposed on the outer periphery of the input shaft 42 and first and second internal gears 54 and 56 meshing with the external gear 52. The external gear 52 is rotatably supported on the input shaft 42 via a gear bearing 30 disposed between the gear drive unit 58 and the external gear 52. In this embodiment, the external gear 52 is flexible, and if the input shaft 42 rotates, its flexural deformation is an ellipse conforming to the shape of the gear drive unit 58.

[0025] The first internal gear 54 is disposed on the opposite side of the load. The second internal gear 56 is disposed on the load side. The first internal gear 54 has a different number of internal teeth than the external gear 52, and the second internal gear 56 has the same number of internal teeth as the external gear 52. In the reduction mechanism 44 of this embodiment, for each revolution of the input shaft 42, the external gear 52 and the second internal gear 56 rotate together at a speed corresponding to the difference in the number of teeth between the external gear 52 and the first internal gear 54.

[0026] The reducer housing 48 of this embodiment includes a first housing component 48A that also serves as the first internal gear 54 and a second housing component 48B disposed radially outward relative to the second internal gear 56. The first housing component 48A and the second housing component 48B are connected to each other as a single unit by screws or the like. A main bearing 59 is disposed between the reducer housing 48 and the second internal gear 56.

[0027] In this embodiment, the output component 50 is a wheel frame 46, which outputs the rotation from the reduction mechanism 44 to the second target component 14. Alternatively, the output component 50 may be a reduction gear housing 48.

[0028] The housing 24 includes the aforementioned reducer housing 48 that houses the reduction mechanism 44 and the motor housing 60 that houses the motor 16. The reducer housing 48 is connected to the motor housing 60 as a single unit by bolts or the like.

[0029] The detector 26 in this embodiment is a rotary encoder. The detector 26 includes a detected component 62 that can rotate integrally with the shaft 22 and a sensor 64 capable of detecting the detected component 62. The detected component 62 is a code disk, and the sensor 64 is, for example, an optical sensor or a magnetic sensor. The detector 26 detects the detected component 62 via the sensor 64, thereby detecting the rotation of the shaft 22. In this embodiment, the detected component 62 is disposed at the load-opposite end 22a of the shaft 22. The sensor 64 is disposed at a position opposite to the detected component 62 in the axial direction X. In this embodiment, the sensor 64 is mounted on a circuit board 66 for controlling the motor 16. The circuit board 66 is mounted to the motor housing 60 via a board bracket 68.

[0030] Brake 28 is disposed on the load side relative to motor 16. Brake 28 is disposed between motor 16 and reducer 20. Brake 28 includes brake rotor 70 mounted on shaft 22, brake mechanism 72 for braking brake rotor 70, and brake body 74 mounted on brake mechanism 72. Brake 28 in this embodiment is a disc brake. Brake mechanism 72 is, for example, a combination of coil and spring. Brake mechanism 72 is configured such that multiple friction members 76 clamp brake rotor 70, thereby using the friction of friction members 76 to brake brake rotor 70 and shaft 22.

[0031] The plurality of bearings 30, 32, and 34 includes a gear bearing 30 disposed between the gear (external gear 52) of the reduction mechanism 44 driven by the gear drive unit 58 of the shaft 22 and the shaft 22. Furthermore, the plurality of bearings 30, 32, and 34 also includes input bearings 32 and 34 spaced apart from the gear bearings 30 in the axial direction X. In this embodiment, the gear bearings 30 are individually provided corresponding to the plurality of internal gears 54 and 56, and are disposed inside the corresponding internal gears 54 and 56. The input bearings 32 and 34 in this embodiment include a first input bearing 32 disposed on the load-opposite side in the axial direction relative to the gear bearings 30, and a second input bearing 34 disposed on the load side in the axial direction relative to the gear bearings 30.

[0032] The gear bearing 30 in this embodiment is a so-called vibratory bearing. The gear bearing 30 is a rolling bearing such as a roller bearing. The gear bearing 30 includes multiple rolling elements 78 such as rollers and a cage 80 that holds the multiple rolling elements 78. The gear bearing 30 in this embodiment does not have a dedicated inner ring. Instead, the outer periphery of the shaft 22 (the gear bearing mounting portion 90 described later) functions as an inner ring. Similarly, the gear bearing 30 does not have a dedicated outer ring; the inner periphery of the external gear 52 functions as an outer ring. Alternatively, the gear bearing 30 may also have dedicated outer and inner rings.

[0033] The first input bearing 32 is disposed between the housing 24 and the shaft 22. The second input bearing 34 is disposed between the wheel frame 46 and the shaft 22. The first input bearing 32 and the second input bearing 34 are rolling bearings such as ball bearings.

[0034] refer to Figure 2 and Figure 3 .exist Figure 2 Rotor 38 is schematically shown in the diagram. Furthermore, in... Figure 2 For ease of explanation, the metal part 106 described later is marked with a dot pattern. The shaft 22 has a hollow portion 82 extending through the shaft 22 along the axial direction X. The shaft 22 has a detector mounting portion 84 for mounting the detected component 62, which is a component of the detector 26, and a rotor mounting portion 86 for mounting the rotor 38. In addition, the shaft 22 also has a brake mounting portion 88 for mounting the brake rotor 70, which is a component of the brake 28, and a plurality of bearing mounting portions 90, 92, and 94 for mounting the bearings 30, 32, and 34.

[0035] In this embodiment, the detector mounting section 84 is provided at the load-opposite end 22a of the shaft 22. The rotor mounting section 86 and the brake mounting section 88 are provided on the outer periphery of the portion of the shaft 22 that becomes the rotor shaft 18. The bearing mounting sections 90, 92, and 94 are provided on the outer periphery of the portion of the shaft 22 that becomes the input shaft 42.

[0036] The brake mounting section 88 includes a plurality of protrusions 88a spaced apart circumferentially. The plurality of protrusions 88a constitute an external spline. The brake rotor 70 includes an internal spline 70a disposed on the inner periphery of the brake rotor 70. The brake rotor 70 is fixed to the brake mounting section 88 in a manner that allows it to move axially (X) by engaging the internal spline 70a with the external spline formed by the plurality of protrusions 88a. The method of fixing the brake rotor 70 to the brake mounting section 88 is not particularly limited; for example, a press-fit engagement without a spline can also be used.

[0037] The bearing configuration units 90, 92, and 94 include a gear bearing configuration unit 90 corresponding to the gear bearing 30, a first input bearing configuration unit 92 corresponding to the first input bearing 32, and a second input bearing configuration unit 94 corresponding to the second input bearing 34. Bearings 30, 32, and 34 corresponding to the bearing configuration units 90, 92, and 94 are configured in the bearing configuration units 90, 92, and 94.

[0038] A gear bearing mounting section 90 is provided on the outer periphery of the gear drive section 58 of the shaft 22. In this embodiment, the gear bearing mounting section 90 has a rolling surface 91 for the rolling elements 78 of the gear bearing 30 to roll. Input bearing mounting sections 92 and 94 are provided at positions offset from the gear bearing 30 in the axial direction X. The inner ring of the first input bearing 32 is disposed in the first input bearing mounting section 92. The inner ring of the first input bearing 32 is fixed to the first input bearing mounting section 92 by a pressing fit or the like. The inner ring of the second input bearing 34 is disposed in the second input bearing mounting section 94. The inner ring of the second input bearing 34 is fixed to the second input bearing mounting section 94 by a pressing fit or the like.

[0039] Additionally, the shaft 22 also includes a groove-shaped retaining ring mounting portion 98 for mounting the retaining ring 96. The retaining ring 96 restricts the axial movement of the inner ring of the first input bearing 32. The retaining ring mounting portion 98 is mounted on the load side in the axial direction relative to the first input bearing mounting portion 92.

[0040] The shaft 22 includes a shaft body 100 extending from inside the motor 16 to inside the reducer 20, and an input shaft assembly 102 disposed on the outer periphery of the shaft body 100 within the reducer 20. The shaft body 100 is continuous from the load-opposite end 22a to the load-side end 22b of the shaft 22. A detector assembly 84, a rotor assembly 86, and a brake assembly 88 are provided on the shaft body 100. The input shaft assembly 102 constitutes the outer periphery of the input shaft 42. Multiple bearing assemblies 90, 92, and 94 are provided on the input shaft assembly 102.

[0041] The shaft 22 is an integral structure formed by a resin portion 104 made of a resin-based material and a metal portion 106 made of a metal-based material. The resin-based material referred to here means a material in which resin is the primary material. Examples of resins used here include general-purpose engineering plastics and special engineering plastics. When using general-purpose engineering plastics, examples include polyamide (e.g., PA46) and polyaldehyde resin. Resin-based materials also include composite materials where the resin is the primary material and other materials are combined. Examples of such composite materials include carbon fiber reinforced resin and glass fiber reinforced resin. The metal-based material referred to here means a material in which metal is the primary material. Examples of metals used here include cast iron, steel, and other ferrous materials, and aluminum alloys and other aluminum-based materials.

[0042] Generally, the density of resin is less than that of metal. Alternatively, the density of the resin-based material constituting the resin portion 104 [kg / m³] can be described as follows: 3 The density of metallic materials less than 106 that constitute the metallic part [kg / m³] 3 ].

[0043] Furthermore, metals generally have greater wear resistance than resins. In other words, the relative wear amount of the metal-based material constituting the metal part 106 is less than the relative wear amount of the resin-based material constituting the resin part 104. This relative wear amount can be obtained through a wear test in which another object component slides relative to the mentioned object part. This wear test measures the wear amount when the object component slides on the sliding surface of a sample cut from the mentioned object part. Relative wear amount [mm] 2 [ / kgf] can be the load [kgf] applied vertically to the sliding surface, the sliding distance [mm] when the object component slides under the condition of applying the load to the sliding surface, and the wear amount of the sample based on the sliding [mm]. 3 The relative wear of the metal part 106 and the relative wear of the resin part 104 are expressed as follows (1). The relative wear of the metal part 106 and the relative wear of the resin part 104 are obtained by conducting a wear test under the same sliding conditions. The "same sliding conditions" means that the surface roughness of the sliding surface of the sample or the object part is the same, the material of the object part is the same, and the lubrication conditions such as the presence or absence or composition of the lubricant are the same.

[0044] Relative wear amount = wear amount / (sliding distance × load)……(1)

[0045] The resin portion 104 is an injection-molded article that can be obtained by injection molding. More specifically, as described later, the resin portion 104 is part of an insert-molded article that can be obtained by insert molding the metal portion 106 as an insert. The metal portion 106 is a machined metal article that can be obtained by metal processing such as machining or casting.

[0046] The resin portion 104 constitutes the shaft body 100 of the shaft 22. Similarly, the resin portion 104 constitutes the detector mounting portion 84, the rotor mounting portion 86, and the brake mounting portion 88. The resin portion 104 constitutes all parts of the shaft 22 except for the metal portion 106.

[0047] The metal portion 106 constitutes the outer peripheral portion of the shaft 22 within the reducer 20. Alternatively, the metal portion 106 constitutes the input shaft component 102 of the shaft 22. The metal portion 106 at least constitutes the outer peripheral portion of the gear drive unit 58 (i.e., the gear bearing mounting portion 90). The rolling surface 91 of the gear bearing mounting portion 90 is formed by the metal portion 106. Furthermore, the metal portion 106 in this embodiment also constitutes a pair of input bearing mounting portions 92 and 94. The metal portion 106 constitutes the bearing mounting portions 90, 92, and 94 for mounting the bearings 30, 32, and 34 used in the reducer 20. The metal portion 106 constitutes the outer peripheral portion of the shaft 22 in the axial range from the first input bearing mounting portion 92 to the second input bearing mounting portion 94.

[0048] The metal part 106, rotor 38, and detector 26 are integrated into the resin part 104 by insert molding. Alternatively, the shaft 22 is a one-piece molded product in which the metal part 106, rotor 38, and component 108 are integrated into the resin part 104 as inserts.

[0049] When the rotor 38 and the resin portion 104 are integrally formed by insert molding, a portion of the resin portion 104 can be inserted into the minute gaps between the plurality of metal plates 40a. These gaps are formed between the plurality of metal plates 40a on the inner periphery of the rotor core 40. As a result, the bonding strength between the rotor core 40 and the resin portion 104 in the axial direction X can be improved.

[0050] refer to Figures 2-4 The metal part 106 has an outer cylindrical portion 110 that forms the outer periphery of the input shaft 42. The aforementioned bearing mounting portions 90, 92, and 94 are provided on the outer periphery of the outer cylindrical portion 110.

[0051] The resin portion 104 includes an inner cylindrical portion 112 disposed inside the outer cylindrical portion 110. The inner cylindrical portion 112 is cylindrical in shape. The outer cylindrical portion 110 and the inner cylindrical portion 112 constitute a single cylindrical portion with radial thickness in the shaft 22.

[0052] The outer cylindrical portion 110 has a metal protrusion 114, which is disposed on the inner circumferential portion of the outer cylindrical portion 110 and protrudes radially inward. In this embodiment, a plurality of metal protrusions 114 are provided at intervals along the circumferential direction. In this embodiment, the metal protrusion 114 is a protrusion extending along the axial direction X.

[0053] The inner cylindrical portion 112 has a resin recess 118 for inserting the metal protrusion 114. The resin recess 118 is concave in the shape of a groove extending radially inward from the outer periphery of the inner cylindrical portion 112. The resin recess 118 is individually provided corresponding to each metal protrusion 114, and a plurality of them are provided at intervals along the circumference. In this embodiment, the resin recess 118 is a groove extending axially, and the entire axial range of the protrusion (i.e., the metal protrusion 114) is inserted therein.

[0054] In this embodiment, the resin recess 118 forms a through hole that radially penetrates the inner cylindrical portion 112, and the metal protrusion 114 radially penetrates the resin recess 118. Thus, the inner peripheral portion of the metal protrusion 114 is exposed to the hollow portion 82 of the shaft body 22, forming the inner peripheral portion of the hollow portion 82. In this embodiment, the inner peripheral surface of the metal protrusion 114 and the inner peripheral surface of the inner cylindrical portion 112 are provided to be in the same plane. Thus, the metal protrusion 114 and the inner cylindrical portion 112 form a smooth and continuous inner peripheral surface of the hollow portion 82.

[0055] refer to Figure 5 In this embodiment, the resin portion 104 includes a displacement limiting portion 120, which contacts the constituent component 108 of the detector 26 to limit its displacement. In this embodiment, the displacement limiting portion 120 is a protrusion provided on the detector mounting portion 84. The displacement limiting portion 120 contacts the constituent component 108 in the circumferential direction, thereby limiting its circumferential displacement. Furthermore, the displacement limiting portion 120 can also contact the opposite side of the load in the axial direction of the constituent component 108 to limit its axial X-direction displacement.

[0056] refer to Figure 6 (a) An example of a method for insert forming of shaft 22 using forming apparatus 130 is described.

[0057] First, the molding apparatus 130 will be described. The molding apparatus 130 includes a plurality of molding dies 134A and 134B that form cavities 132 corresponding to the shape of the shaft 22. The plurality of molding dies 134A and 134B includes a first molding die 134A that molds the outer peripheral portion of the resin portion 104 and a second molding die 134B that can mold the inner peripheral portion of the resin portion 104. In addition, the number of molding dies 134A and 134B is not particularly limited, and there may be more than three.

[0058] Next, the insert molding method will be explained. First, as... Figure 6 As shown in (a), a cavity 132 for molding the shaft 22 is formed by closing multiple molding dies 134A and 134B. At this time, the metal part 106, which will be an insert, the rotor 38, and the constituent components 108 of the detector 26 are arranged in the molding dies 134A and 134B.

[0059] Next, as Figure 6 As shown in (b), molten resin 136 is poured into the cavity 132 and then cured. This results in a shaft 22 in which the resin portion 104 and the insert (metal portion 106, etc.) are integrally formed.

[0060] Next, as Figure 6 As shown in (c), multiple molding dies 134A and 134B are opened, and the shaft 22, which is the molded product, is demolded. At this time, for example, the first molding die 134A is moved toward the load side (upper side in the figure) in the direction Pa to open the die, and the shaft 22 is moved toward the direction Pa to demold from the second molding die 134B.

[0061] Next, the effects of the gear motor 10 will be explained.

[0062] In the shaft body 22, the resin portion 104 and the metal portion 106 are integrated. Therefore, compared to the case where the shaft body 22 is composed only of the metal portion 106, the shaft body 22 can be made lighter.

[0063] Generally, resin molding, such as injection molding, is advantageous in terms of manufacturing cost and time compared to metal processing such as machining. A portion of the shaft 22 is composed of a resin portion 104. Therefore, according to this embodiment, compared to the case where the shaft 22 is composed solely of a metal portion 106, a reduction in manufacturing cost and a reduction in manufacturing time can be achieved.

[0064] When machining metal using cutting machines such as lathes, the workpiece must be clamped in a chuck during cutting. This introduces process deviations, where the machining conditions change in each machining operation. These machining conditions include, for example, the workpiece dimensions or the clamping method (the clamping position relative to the workpiece). Due to these process deviations during metal machining, the dimensional accuracy of the finished product will deviate significantly.

[0065] In contrast, when the resin portion 104 is obtained by injection molding, the shape of the molding die is transferred to the resin portion 104. Therefore, as long as the dimensional accuracy of the molding die is ensured, the dimensional accuracy of the resin portion 104 will be the same as that of the molding die, and no process deviations as in metal processing will occur. Therefore, according to this embodiment, compared to the case where the shaft 22 is composed only of the metal portion 106, the dimensional accuracy of a portion of the shaft 22 (the resin portion 104) can be easily ensured.

[0066] When the reduction mechanism 44 is operating, a large load is applied to the outer periphery of the shaft 22 within the reducer 20. Specifically, bending force is input as a large load from the reduction mechanism 44 to the outer periphery of the shaft 22 (gear bearing configuration 90). Simultaneously, the reaction force of the bending force acts from the input bearings 32 and 34 onto the input bearing configurations 92 and 94 of the shaft 22. Thus, a large load is applied to the outer periphery of the shaft 22 within the reducer 20 (bearing configurations 90, 92, and 94), therefore requiring strength to withstand such a large load.

[0067] The metal part 106 is disposed on the outer periphery of the shaft body 100 within the reducer 20. Therefore, the metal part 106 can withstand the aforementioned large load. Thus, the durability of parts requiring strength can be ensured by the metal part 106, and the shaft 22 can be made lighter by the resin part 104.

[0068] In the shaft 22, the bearing configuration sections 90, 92, and 94, which bear heavy loads, are formed by metal parts 106. Therefore, the durability of parts requiring particular strength can be ensured by the metal parts 106, and the lightweight of the shaft 22 can be achieved by the resin parts 104.

[0069] The rolling surface 91 on which the rolling element 78 rolls is required to be wear-resistant. In the shaft 22, this wear-resistant part is constituted by a metal portion 106. Therefore, the wear resistance on the rolling surface 91 can be ensured by the metal portion 106, and the shaft 22 can be made lighter by the resin portion 104.

[0070] The resin portion 104 constitutes the detector mounting section 84, the rotor mounting section 86, and the brake mounting section 88. Compared to the portion that forms the input shaft 42 of the reducer 20, these portions are less susceptible to large loads. By using the resin portion 104 to constitute such a load-bearing part, a lightweight design can be reasonably achieved.

[0071] The resin portion 104 constitutes a brake mounting portion 88 having multiple protrusions 88a. Therefore, compared to forming the multiple protrusions 88a into a metal portion 106 by machining or the like, the processing cost can be reduced.

[0072] The outer cylindrical portion 110 of the metal portion 106 has a metal protrusion 114, and the inner cylindrical portion 112 of the resin portion 104 has a resin recess 118 for the metal protrusion 114 to be inserted. The metal protrusion 114 and the resin recess 118 increase the contact area between the metal portion 106 and the resin portion 104 in both the circumferential and axial directions. Furthermore, this improves the bonding strength between the metal portion 106 and the resin portion 104.

[0073] The component 108 comprising the metal part 106, rotor 38, and detector 26 is integrally formed with the resin part 104 via insert molding. Therefore, there is no need to perform assembly work between the component 108 and the resin part 104 to integrate the metal part 106, rotor 38, and detector 26. Furthermore, the effects of assembly deviations during assembly can be eliminated, easily ensuring the positional accuracy of the relative positions between the component 108 and the resin part 104.

[0074] When assembling the shaft 22 and the rotor 38, the inner circumference of the rotor 38 needs to be machined to ensure high dimensional accuracy in order to ensure the positional accuracy of the rotor 38. In contrast, if insert molding is used, no assembly is required, thus also having the advantage of not needing to perform machining to ensure the dimensional accuracy of the rotor 38.

[0075] Next, other variations of each constituent element will be explained.

[0076] The application of gear motor 10 is not particularly limited. For example, in addition to industrial robotic arms, gear motor 10 can also be used in automated guided vehicles (AGVs) and other automated transport vehicles.

[0077] The type of motor 16 is not particularly limited. For example, in addition to a permanent magnet motor using permanent magnets as in the embodiment, the motor 16 can also be an induction motor, a reluctance motor, etc. The rotor 38 can also be a squirrel-cage rotor, a wound rotor, etc. In any case, the rotor 38 can have a rotor core 40 composed of laminated bodies. Furthermore, the rotor core 40 can also be composed of metal bushings. In addition, the rotor 38 can also be a coreless rotor without a rotor core 40.

[0078] The specific example of the reduction mechanism 44 is not particularly limited. Besides a flexural gear mechanism, the reduction mechanism 44 can also use, for example, an eccentric oscillating gear mechanism, a planetary gear mechanism, an orthogonal axis gear mechanism, or a parallel axis gear mechanism. When a flexural gear mechanism is used, its specific example is not particularly limited. Besides a cylindrical shape, it can also be a cup shape or a top hat shape. When the reduction mechanism 44 uses an eccentric oscillating gear mechanism, the gear drive part 58 of the shaft 22 is composed of an eccentric part that is eccentric relative to the rotation center line.

[0079] The gear motor 10 may also be without the detector 26. The detector 26 is not limited to a rotary detector; for example, a pressure detector, a temperature detector, etc., may also be used. When a rotary detector is used for the detector 26, its specific example is not particularly limited, and a Hall IC, etc., may be used. The constituent components 108 of the detector 26 disposed on the detector mounting section 84 of the shaft 22 are also not particularly limited.

[0080] The geared motor 10 may also be without a brake 28. Specific examples of the brake 28 are not limited to disc brakes; for example, a drum brake may also be used. The placement of the brake 28 is not particularly limited. For example, the brake 28 may be placed on the opposite side of the load of the motor 16.

[0081] The above describes an example of the outer periphery of the shaft body 100, in which the resin portion 104 constitutes the shaft body 100 and the metal portion 106 is disposed within the reducer 20. Alternatively, the shaft body 100 may be configured such that the metal portion 106 constitutes the shaft body 100, and the resin portion 104 is disposed within the reducer 20. Furthermore, the rotor shaft 18 may be configured such that one of the resin portion 104 and the metal portion 106 constitutes the rotor shaft 18, and the other portion constitutes the input shaft 42. Regardless of the configuration, the shaft 22 can be a structure in which the resin portion 104 and the metal portion 106 are integrally formed; the specific positions of the portions 104 and 106 are not particularly limited.

[0082] The above describes all examples of the metal portion 106 constituting multiple bearing mounting portions 90, 92, and 94. However, the metal portion 106 may also constitute only one of them. Furthermore, the metal portion 106 may also be located in a location other than the bearing mounting portions 90, 92, and 94 on the outer periphery of the shaft body portion 100 within the reducer 20.

[0083] The gear bearing mounting section 90 may not form the rolling surface 91. For example, the gear bearing 30 may have a dedicated inner ring, which is mounted in the gear bearing mounting section 90. Furthermore, the input bearing mounting sections 92 and 94 may also form rolling surfaces for the rolling elements of the input bearings 32 and 34 to roll.

[0084] The above description illustrates an example where the detector mounting section 84, rotor mounting section 86, and brake mounting section 88 of the shaft 22 are constructed from resin portions 104. However, one or all of them may also be constructed from metal portions 106.

[0085] Alternatively, the outer cylindrical portion 110 may not have a metal protrusion 114, and the inner cylindrical portion 112 may not have a resin recess 118. The number of metal protrusions 114 and resin recesses 118 is not particularly limited. For example, there may be only one metal protrusion 114 and one resin recess 118.

[0086] The above description illustrates an example where the outer cylindrical portion 110 of the metal part 106 constitutes the outer peripheral portion of the input shaft 42, but its position on the shaft body 22 is not particularly limited. The outer cylindrical portion 110 may also constitute the outer peripheral portion of the rotor shaft 18, for example.

[0087] The resin recess 118 may also be formed as a bottomed hole that does not penetrate radially through the inner cylindrical portion 112. For example, the resin recess 118 may be formed by a bottomed hole having a bottom on the radially inner side.

[0088] The above describes an example of the metal part 106 being integrally formed with the resin part 104 via insert molding. The method by which the metal part 106 and the resin part 104 are integrally formed is not particularly limited. For example, the metal part 106 and the resin part 104 can also be integrally formed by fitting, bonding, snap-fit, etc. The rotor 38 is similarly integrated with the resin part 104. The constituent components 108 of the detector 26 are also similarly integrated with the resin part 104. Alternatively, a portion of the metal part 106, the rotor 38, and the constituent components 108 can be integrally formed with the resin part 104 via insert molding, and the remaining portions can be integrally formed with the resin part 104 by methods other than insert molding.

[0089] The above embodiments and variations are merely illustrative. These abstract technical concepts should not be interpreted as limiting the scope of the embodiments and variations. The embodiments and variations can undergo various design changes, such as alterations, additions, and deletions of constituent elements. In the above embodiments, the phrase "embodiment" is used to emphasize the aspects where such design changes are possible. However, design changes are also permitted even without this phrase. The shaded lines on the cross-sections in the accompanying drawings are not intended to limit the material of the objects marked with shaded lines.

Claims

1. A geared motor comprising a motor and a reducer, characterized in that, The gear motor has a shaft body that is integrally formed by a rotor shaft that rotates under the drive of the motor and the input shaft of the reducer. The shaft is a structure formed by integrating a resin part made of resin-based material and a metal part made of metal-based material. The resin portion constitutes the main shaft body from inside the motor to inside the reducer. The metal portion is disposed on the outer periphery of the shaft body portion within the reducer. The resin portion constitutes a rotor mounting section for mounting the rotor of the motor, and the rotor of the motor is mounted on the outer peripheral portion of the resin portion. The rotor is integrated with the resin portion through insert molding.

2. The gear motor according to claim 1, characterized in that, The metal portion constitutes a bearing mounting section for arranging the bearings used in the speed reducer.

3. The gear motor according to claim 2, characterized in that, The metal portion forms the rolling surface for the rolling elements of the bearing to roll.

4. The gear motor according to claim 2, characterized in that, The metal portion constitutes the bearing mounting portion for mounting the inner ring of the bearing.

5. The gear motor according to any one of claims 1 to 4, characterized in that, The resin portion constitutes a brake mounting section for mounting the brake.

6. The gear motor according to claim 5, characterized in that, The brake configuration section has a plurality of protrusions arranged at intervals along the circumference.

7. The gear motor according to any one of claims 1 to 4, characterized in that, The resin portion constitutes a detector mounting section, which is a component for mounting the detector. The constituent components are integrated with the resin portion through insert molding.

8. The gear motor according to claim 7, characterized in that, The metal portion has an outer cylindrical section. The resin portion includes an inner cylindrical portion disposed on the inner side of the outer cylindrical portion. The outer cylindrical portion has a metal protrusion that protrudes radially inward. The inner cylindrical portion has a resin recess for the metal protrusion to be inserted.

9. The gear motor according to any one of claims 1 to 4, characterized in that, The metal portion is integrated with the resin portion through insert molding.

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