Encoder, motor with encoder, and method for manufacturing motor with encoder

Abstract

This encoder (20) according to an embodiment 1 comprises: a boss (21); a rotary plate (22); an optical module (23); a substrate (24); and a frame (30) provided between the substrate (24) and a bracket (12) of a motor (10). The bracket (12) has a main surface (13) facing the frame (30). The frame (30) has a frame body (31) extending along the main surface (13). The frame (30) also has: a first end portion (32) that is provided on one end side of the frame body (31) and has a first alignment hole (32a) formed therein; and a second end portion (33) that is provided on the other end side of the frame body (31) and has a second alignment hole (33a) formed therein.

Description

Encoder, motor with encoder, and method for manufacturing motor with encoder

[0001] The present disclosure relates to an encoder, a motor with an encoder, and a method for manufacturing a motor with an encoder.

[0002] Conventionally, an encoder that detects the rotational position of a shaft included in a motor is known (for example, see Patent Document 1). The encoder in Patent Document 1 includes a hollow shaft coupled to the motor shaft, a rotating disk attached to the hollow shaft, and an encoder housing connected to the hollow shaft via a bearing.

[0003] Japanese Patent Application Laid-Open No. 2004-104889

[0004] Encoders are classified into optical and magnetic types. Optical encoders generally include an optical module that irradiates a rotating disk with light and receives the reflected or transmitted light. When attaching such an encoder to a motor, the optical module must be positioned with high precision relative to the rotating disk. However, positioning such an optical module reduces productivity, especially when it is performed on large motors. In light of this situation, the present disclosure provides an encoder, a motor with an encoder, and a method for manufacturing a motor with an encoder that allows for easy positioning of the optical module.

[0005] One aspect of the present disclosure relates to an encoder. The encoder includes a boss that rotates around a rotation axis of a shaft of a motor that includes a bracket and a shaft, and a rotating plate that is fixed to the boss and rotates around the rotation axis. The encoder also includes an optical module that has a light source that irradiates light onto the rotating plate and a light-receiving element that receives light reflected from or transmitted through the rotating plate, a substrate to which the optical module is fixed, and a frame that is provided between the substrate and the bracket. The bracket has a main surface that faces the frame. The frame has a frame main body that extends along the main surface, a first end portion that is provided on one end of the frame main body and has a first alignment hole formed therein, and a second end portion that is provided on the other end of the frame main body and has a second alignment hole formed therein.

[0006] Another aspect of the present disclosure relates to a motor with an encoder, which includes the above-mentioned encoder, a motor body having a bracket to which a frame is attached, a shaft attached to a boss, and two bearings that rotatably support the shaft.

[0007] Another aspect of the present disclosure relates to a method for manufacturing a motor with an encoder. The method includes a first preparation step of preparing a frame having a frame main body, a first end portion on one end of the frame main body and having a first alignment hole formed therein, and a second end portion on the other end of the frame main body and having a second alignment hole formed therein. The method also includes a second preparation step of preparing a master fixture including a master main body on which the frame main body can be mounted, a master shaft rotatable relative to the master main body, and a master rotary plate rotatable together with the master shaft. The method also includes a third preparation step of preparing a jig including first and second alignment pins corresponding to the first and second alignment holes, respectively, and a cylindrical portion having a shaft hole through which the master shaft can be inserted. The method also includes a fourth preparation step of preparing a substrate on which an optical module having a light source and a light receiving element is fixed. The manufacturing method also includes a fifth preparation step of preparing a motor assembly including a bracket having a main surface on which a frame main body can be mounted, a shaft, and a rotating plate, wherein the positional relationship between the shaft and the rotating plate is the same as the positional relationship between the master shaft and the master rotating plate.The manufacturing method also includes a first placement step of placing the frame in a predetermined positional relationship with the master facility by inserting the master shaft of the master facility into the shaft hole of the jig and inserting the first alignment pin and the second alignment pin of the jig into the first alignment hole and the second alignment hole of the frame.The manufacturing method also includes a fixing step of adjusting the position of the substrate to the frame placed on the master facility and fixing it. The manufacturing method also includes a second positioning step in which the frame to which the substrate is fixed is positioned relative to the motor assembly using a jig, in which the shaft of the motor assembly is inserted into the shaft hole of the jig and the first alignment pin and second alignment pin of the jig are inserted into the first alignment hole and second alignment hole of the frame, thereby positioning the frame to which the substrate is fixed in a predetermined positional relationship relative to the motor assembly.

[0008] According to the present disclosure, it is possible to provide an encoder that allows easy positioning of an optical module, a motor with an encoder, and a method for manufacturing a motor with an encoder.

[0009] FIG. 1 is a cross-sectional view schematically showing a motor with an encoder according to a first embodiment. FIG. 2A is a perspective view schematically showing a frame of the encoder according to the first embodiment. FIG. 2B is a plan view schematically showing the frame of the encoder according to the first embodiment. FIG. 3 is a perspective view schematically showing a master facility according to the first embodiment. FIG. 4 is a perspective view showing a state in which a frame is arranged relative to the master facility using a jig. FIG. 5 is a perspective view showing a state in which a substrate is fixed to the frame arranged relative to the master facility. FIG. 6 is a perspective view schematically showing a motor assembly according to the first embodiment. FIG. 7 is a perspective view showing a state in which a frame to which a substrate is fixed is attached relative to the motor assembly using a jig. FIG. 8A is a perspective view schematically showing a frame according to a second embodiment, with images of each alignment pin added. FIG. 8B is a side cross-sectional view schematically showing a state in which the frame is biased. FIG. 9 is a plan view schematically showing a frame and a substrate according to the second embodiment. FIG. 10 is a perspective view schematically showing a frame according to a third embodiment.

[0010] The following describes examples of embodiments of an encoder, a motor with an encoder, and a method for manufacturing a motor with an encoder according to the present disclosure. However, the present disclosure is not limited to the examples described below. While the following description may use specific numerical values ​​and materials, other numerical values ​​and materials may be used as long as the effects of the present disclosure are obtained.

[0011] (Encoder) The encoder according to the present disclosure is attached to a motor including a bracket and a shaft, and is configured to detect at least the rotational position of the shaft. The encoder according to the present disclosure includes a boss, a rotating plate, an optical module, a substrate, and a frame.

[0012] The boss rotates around the rotation axis of the motor shaft. The boss may be fixed to the shaft by a bolt. The boss may be made of a metal material such as stainless steel.

[0013] The rotating plate is fixed to the boss and rotates around the rotation axis of the shaft. The rotating plate may rotate around the rotation axis integrally with the boss. The rotating plate may have a predetermined pattern formed along its circumferential direction. The predetermined pattern may be a pattern used to detect the rotation position of the shaft, or a pattern used to detect the rotation position and rotation number of the shaft. The rotation position of the shaft refers to the relative angular position or absolute angular position of the shaft. The rotation number of the shaft refers to the number of times the shaft has rotated.

[0014] The rotating plate may be opaque or transparent. Opaque means, for example, blocking 90% or more of ultraviolet light or visible light. Transparent means, for example, transmitting 90% or more of ultraviolet light or visible light. The rotating plate may be made of a metal material such as stainless steel. The rotating plate may be formed in a circular (or disk-like) shape. A circular shape refers to a shape in which 80% or more of the outer shape is formed by an arc.

[0015] The optical module includes a light source that irradiates the rotating plate with light and a light-receiving element that receives light reflected or transmitted from the rotating plate. The light source and the light-receiving element may both be located on one side of the rotating plate, in which case the light-receiving element receives light emitted from the light source and reflected by the rotating plate. Alternatively, one of the light source and the light-receiving element may be located on one side of the rotating plate and the other on the other side of the rotating plate, in which case the light-receiving element receives light emitted from the light source and transmitted through the rotating plate. The light-receiving element may convert the received light into an electrical signal. This electrical signal may be used to determine at least one of the rotational position and the rotation speed of the shaft.

[0016] The optical module is fixed to the substrate. Various electronic components other than the optical module may be mounted on the substrate. The shape of the substrate is not particularly limited, and may be, for example, substantially arch-shaped. The substrate may be fixed to a bracket of the motor together with the frame.

[0017] The frame is provided between the substrate and the bracket. The shape of the frame is not particularly limited, and may be, for example, substantially arch-shaped.

[0018] The bracket has a main surface facing the frame.

[0019] The frame has a frame main body portion, a first end portion, and a second end portion. The frame main body portion extends along a main surface of the bracket. The frame main body portion may be formed, for example, in an arch shape. The first end portion is provided on one end side of the frame main body portion. A first alignment hole is formed in the first end portion. The second end portion is provided on the other end side of the frame main body portion. A second alignment hole is formed in the second end portion. Each of the first alignment hole and the second alignment hole may be a through hole that passes through the frame in the thickness direction, or may be a blind hole that does not pass through the frame in the thickness direction.

[0020] When attaching an encoder having the above configuration to a motor, the optical module can be easily positioned using the first and second alignment holes. Specifically, the frame is placed on a master fixture simulating the motor's bracket and shaft and the encoder's rotating plate using a jig that can determine the positional relationship between the master fixture's shaft and the frame's first and second alignment holes. With the frame placed on the master fixture, i.e., with the positional relationship between the master fixture's rotating plate and the frame defined, the substrate with the optical module attached is positioned and fixed to the frame. At this stage, an assembly (hereinafter also referred to as a substrate assembly) is formed in which the frame and substrate are combined. Next, the substrate assembly is removed from the master fixture and attached to the motor to which the encoder will actually be attached. During this attachment, the same jig used to form the substrate assembly is used to determine the positional relationship between the motor's shaft with the rotating plate attached and the frame's first and second alignment holes in the same manner as described above. In this manner, the substrate assembly can be attached to the motor with the optical module positioned relative to the rotating plate. In this way, by utilizing the first alignment hole and the second alignment hole, the positioning state of the optical module achieved in the master equipment can be reproduced in the motor to which the encoder is attached, thereby making it easy to position the optical module.

[0021] A plurality of recesses may be formed in the main surface of the bracket, and at least a portion of the first end may be accommodated in one of the recesses, and at least a portion of the second end may be accommodated in another recess different from the one in which the first end is accommodated.

[0022] In this way, the first and second alignment holes are formed in the first and second ends of the frame, and at least a portion of the first and second ends is received in a recess formed in the motor bracket. This prevents a situation in which the positioning state determined in the master equipment cannot be reproduced in the actual motor due to at least one of misalignment of the bearing that rotatably supports the motor shaft and unintended tilt of the main surface of the bracket.

[0023] The number of recesses is not particularly limited and may be one or two or more, for example, 2. When the number of recesses is one, for example, at least a part of the first end or at least a part of the second end is accommodated in the one recess.

[0024] The inner surface of the first alignment hole and the inner surface of the second alignment hole may each be a smooth surface. However, at least one of the inner surfaces of the first alignment hole and the second alignment hole may be a non-smooth surface, for example, a threaded surface. A smooth surface refers to a surface with a surface roughness Rz of 25 μm or less.

[0025] At least a portion of the inner surface of the first alignment hole may have a tapered surface that narrows toward the bracket. In this configuration, when the jig has an alignment pin that corresponds to the first alignment hole, the tapered surface of the first alignment hole can be used to easily insert the alignment pin into the first alignment hole.

[0026] The diameter of the first alignment hole may be smaller than the diameter of the second alignment hole. In this case, the first alignment hole may be engaged with an alignment pin of the jig with substantially no gap, while the second alignment hole may be engaged with another alignment pin of the jig with a gap, so that the former can be used as a reference for positioning the frame relative to the master fixture or bracket. Note that the diameter of each alignment hole may be the smallest diameter of each alignment hole.

[0027] When viewed from the direction in which the rotation axis extends, the distance between the first alignment hole and the optical module may be smaller than the distance between the second alignment hole and the optical module. In this case, by disposing the optical module relatively close to the first alignment hole, which serves as a reference for frame positioning, it is possible to minimize errors that may occur in the positioning of the frame and, ultimately, the positioning of the optical module due to dimensional errors of various components.

[0028] The first alignment hole may be formed in a circular shape. The second alignment hole may be formed in an oval shape. In this case, when the alignment pin of the jig has a circular cross section, the first alignment hole is used as a positioning reference, and dimensional errors of various components can be absorbed by the oval second alignment hole.

[0029] The first alignment hole and the second alignment hole may be arranged symmetrically with respect to the rotation axis when viewed from the direction in which the rotation axis extends. In this case, by ensuring a maximum distance between the first alignment hole and the second alignment hole in the frame, the accuracy of positioning using the jig can be improved.

[0030] (Motor with Encoder) A motor with an encoder according to the present disclosure includes the above-described encoder, a motor body, a shaft, and two bearings. The motor may be, for example, an inner rotor type three-phase synchronous motor, but is not limited to this.

[0031] The motor body has a bracket to which the encoder frame is attached. The motor body may further have a case to which the bracket is fixed, and a rotor and a stator housed in the case. The rotor may be attached to the shaft. The rotor may have a rotor core made of a magnetic material and a plurality of permanent magnets fixed to the rotor core. The stator may be provided facing the rotor. The stator may have a stator core made of a magnetic material and a plurality of coils wound around the stator core.

[0032] The shaft is attached to the boss of the encoder. The shaft may be attached to the boss by a bolt. The shaft may be made of a magnetic material or a non-magnetic material.

[0033] The two bearings rotatably support the shaft. The two bearings may be arranged on either side of the rotor of the motor body. Each bearing may be, for example, a radial ball bearing, but is not limited to this.

[0034] When viewed from a direction perpendicular to the rotation axis, the surfaces of the first end and the second end facing away from the bracket may overlap with the main surface of the bracket, which can prevent loss of positioning accuracy of the frame due to unintended tilt of the main surface of the bracket when attaching the board assembly to the bracket.

[0035] When viewed from a direction perpendicular to the rotation axis, the surfaces of the first end and the second end facing away from the bracket may be located between the two bearings. In this case, when the board assembly is attached to the bracket, it is possible to prevent loss of positional accuracy of the frame due to misalignment of the two bearings.

[0036] (Method for Manufacturing a Motor with Encoder) The method for manufacturing a motor with encoder according to the present disclosure can be used to manufacture, for example, the motor with encoder described above, but is not limited to this. The method for manufacturing a motor with encoder according to the present disclosure includes a first preparation step, a second preparation step, a third preparation step, a fourth preparation step, a fifth preparation step, a first arrangement step, a fixing step, and a second arrangement step.

[0037] The first preparation step is a step of preparing a frame having a frame main body, a first end, and a second end. The frame main body may be formed, for example, in an arch shape. The first end is provided on one end of the frame main body and has a first alignment hole formed therein. The second end is provided on the other end of the frame main body and has a second alignment hole formed therein. The shape of each alignment hole is not particularly limited and may be, for example, circular, elliptical, or oblong. Each alignment hole may be a through hole or a blind hole.

[0038] The second preparation step is a step of preparing a master facility having a master body, a master shaft, and a master rotating plate. The master body is capable of mounting a frame body portion. The master body may have a master main surface on which the frame body portion can be mounted. The master shaft is rotatable relative to the master body. The diameter of the master shaft may be equal to the diameter of the shaft of the motor with encoder. The master rotating plate is rotatable together with the master shaft. The master shaft and the master rotating plate may have a configuration similar to that of the shaft and rotating plate of the motor with encoder.

[0039] The third preparation step is a step of preparing a jig having first and second alignment pins and a cylindrical portion in which a shaft hole is formed. The first and second alignment pins correspond to the first and second alignment holes, respectively. The cross-sectional shape of each alignment pin is not particularly limited and may be, for example, circular, elliptical, or polygonal. The shaft hole is capable of receiving the master shaft. The inner diameter of the shaft hole may be substantially the same as the outer diameter of the master shaft. Here, "the inner diameter of the shaft hole and the outer diameter of the master shaft being substantially the same" means that, where the former is D1 and the latter is D2, 1≦D1 / D2≦1.05 holds.

[0040] The fourth preparation step is a step of preparing a substrate to which an optical module having a light source and a light receiving element is fixed. The light source may irradiate light onto the rotating plate of the encoder in the completed motor with encoder. The light receiving element may receive light reflected from or transmitted through the rotating plate in the completed motor with encoder. The shape of the substrate is not particularly limited and may be, for example, arch-shaped.

[0041] The fifth preparation step is a step of preparing a motor assembly including a bracket, a shaft, and a rotating plate. The bracket has a main surface on which the frame main body can be mounted. The diameter of the shaft may be equal to the diameter of the master shaft. The rotating plate may have the same configuration as the master rotating plate. The positional relationship between the shaft and the rotating plate in the motor assembly is the same as the positional relationship between the master shaft and the master rotating plate in the master facility. These positional relationships may be positional relationships when viewed from the axial direction of the shaft or the master shaft.

[0042] The first positioning step is a step of positioning the frame in a predetermined positional relationship with respect to the master equipment. Specifically, the first positioning step is a step of inserting the master shaft of the master equipment into the shaft hole of the jig, and inserting the first alignment pin and the second alignment pin of the jig into the first alignment hole and the second alignment hole of the frame. In this way, in the first positioning step, the frame is fixed in a predetermined positional relationship with respect to the master equipment.

[0043] The fixing step is a step of adjusting and fixing the substrate to a frame arranged in the master facility. At this time, the optical module fixed to the substrate may be adjusted in position relative to the master rotating plate of the master facility. The position adjustment of the optical module may be performed by adjusting the position of the substrate to which it is fixed along the main surface of the frame. Furthermore, the position adjustment of the optical module may be performed while checking an electrical signal output from a light receiving element of the optical module when the master shaft and the master rotating plate are rotated.

[0044] The second placement process is a process of placing the frame to which the substrate is fixed relative to the motor assembly using a jig. Specifically, the second placement process is a process of inserting the shaft of the motor assembly through the shaft hole of the jig and inserting the first alignment pin and the second alignment pin of the jig into the first alignment hole and the second alignment hole of the frame. In this way, in the second placement process, the frame to which the substrate is fixed is placed in the above-mentioned predetermined positional relationship with the motor assembly. In other words, in the second placement process, the positional relationship between the frame and the master equipment realized in the first placement process (or the positional relationship between the substrate and the master equipment realized in the fixing process) is reproduced between the frame to which the substrate is fixed and the motor assembly. In this way, in the second placement process, it is possible to position the optical module fixed to the substrate.

[0045] A surface of the master body on which the frame main body can be placed may have a plurality of master recesses formed thereon. A main surface of the bracket may have a plurality of recesses formed thereon. The first positioning step may be performed with at least a portion of each of the first end and the second end of the frame housed in a different one of the plurality of master recesses. The second positioning step may be performed with at least a portion of each of the first end and the second end of the frame housed in a different one of the plurality of recesses. In this case, it is possible to prevent the positioning accuracy of the optical module from being impaired due to, for example, an unintended tilt of the main surface of the bracket.

[0046] The number of master recesses is not particularly limited and may be one or two or more, for example, two. When the number of master recesses is one, for example, at least a portion of the first end or at least a portion of the second end is accommodated in the single master recess. Similarly, the number of recesses is not particularly limited and may be one or two or more, for example, two. When the number of recesses is one, for example, at least a portion of the first end or at least a portion of the second end is accommodated in the single recess.

[0047] As described above, according to the present disclosure, by providing the frame with the first alignment hole and the second alignment hole, the optical module can be easily positioned.

[0048] An example of an encoder, a motor with an encoder, and a method for manufacturing a motor with an encoder according to the present disclosure will be described in detail below with reference to the drawings. The above-described components and processes can be applied to the components and processes of the example encoder, motor with an encoder, and method for manufacturing a motor with an encoder described below. The components and processes of the example encoder, motor with an encoder, and method for manufacturing a motor with an encoder described below can be modified based on the above description. Furthermore, the matters described below may be applied to the above-described embodiment. Among the components and processes of the example encoder, motor with an encoder, and method for manufacturing a motor with an encoder described below, components and processes that are not essential to the encoder, motor with an encoder, and method for manufacturing a motor with an encoder according to the present disclosure may be omitted. Note that the diagrams shown below are schematic and do not accurately reflect the shapes or number of actual components. Furthermore, although terms indicating specific directions, such as "up" and "down," may be used in the following description, these are for convenience of explanation and do not limit the present disclosure.

[0049] 1 to 7, a first embodiment of the present disclosure will be described. First, the configuration of a motor with an encoder 10 (hereinafter also simply referred to as the motor 10) of this embodiment will be described, followed by a description of a method for manufacturing the motor with encoder 10.

[0050] (Motor with Encoder) Fig. 1 is a cross-sectional view that schematically shows a motor with encoder 10 of embodiment 1. Figs. 2A and 2B are a perspective view and a plan view that schematically show a frame 30 of an encoder 20 of embodiment 1. The motor 10 of this embodiment is an inner rotor type three-phase synchronous motor, but is not limited to this. As shown in Fig. 1, the motor 10 includes a motor body 11, a shaft 18, two bearings 19, and an encoder 20.

[0051] The motor main body 11 includes a bracket 12, a case 15, a rotor 16, and a stator 17. A frame 30 (described below) of the encoder 20 is attached to the bracket 12. The bracket 12 faces the frame 30 and has a main surface 13 on which a plurality of (two in this example) recesses 14 are formed. The bracket 12 is fixed to the case 15. The case 15 is a hollow cylindrical member that houses the rotor 16 and the stator 17. The stator 17 is fixed to the inner surface of the case 15. In this embodiment, the case 15 and the bracket 12 are separate bodies, but they may also be integrally formed. The rotor 16 is attached to a shaft 18 and rotates together with the shaft 18 around a rotation axis O. In this embodiment, the rotor 16 is an embedded magnet rotor, but is not limited to this. The stator 17 faces the rotor 16 via an air gap. The stator 17 is provided outside the rotor 16 in the radial direction of the motor 10. The stator 17 in this embodiment is a concentrated winding stator, but is not limited to this.

[0052] The shaft 18 passes through the bracket 12 and the case 15. The shaft 18 is rotatably supported by the bracket 12 via one bearing 19 (the upper bearing 19 in FIG. 1 ), and is rotatably supported by the case 15 via the other bearing 19. The shaft 18 is attached to a boss 21 (described later) of the encoder 20, and rotates together with the boss 21 around its own rotation axis O.

[0053] The two bearings 19 are arranged to sandwich the rotor 16 in the direction in which the rotation axis O extends (the vertical direction in FIG. 1 , hereinafter also referred to as the rotation axis direction). In other words, in the rotation axis direction, one bearing 19 is arranged on one side of the rotor 16, and the other bearing 19 is arranged on the other side of the rotor 16. Each of the two bearings 19 rotatably supports the shaft 18.

[0054] The encoder 20 of this embodiment is a multi-rotation absolute encoder, but is not limited to this. The encoder 20 of this embodiment is a battery-powered encoder, but may also be a battery-less encoder equipped with a permanent magnet and a power generating element. As shown in Figures 1, 2A, and 2B, the encoder 20 includes a boss 21, a rotating plate 22, an optical module 23, a substrate 24, and a frame 30.

[0055] The boss 21 is fixed to the shaft 18 and rotates together with the shaft 18 around the rotation axis O. The boss 21 is made of stainless steel, but is not limited to this.

[0056] The rotating plate 22 is formed in a circular (or annular) shape. The rotating plate 22 is fixed to the boss 21 and rotates together with the boss 21 around the rotation axis O. The rotating plate 22 has a predetermined pattern (not shown) formed along its circumferential direction. The predetermined pattern is used to detect the rotational position and rotation speed of the shaft 18. The rotating plate 22 is made of stainless steel, but is not limited to this. The rotating plate 22 is opaque, but may have a certain degree of translucency. The rotating plate 22 reflects light irradiated from the optical module 23.

[0057] The optical module 23 has a light source (e.g., an LED) that irradiates the rotating plate 22 with light, and a light-receiving element (e.g., a photodiode) (both not shown). The optical module 23 has a substantially rectangular shape when viewed in the direction of the rotation axis, but the shape is not particularly limited. The substantially rectangular shape includes not only a rectangular shape but also a rectangular shape with rounded corners. The light-receiving element receives light that is irradiated from the light source and reflected by the rotating plate 22. The light-receiving element converts the received light into an electrical signal. This electrical signal is used to determine the rotational position and rotation speed of the shaft 18.

[0058] The optical module 23 is fixed to the substrate 24. Although not shown, various electronic components are also mounted on the substrate 24. The substrate 24 has an arch shape overall, and is attached to the bracket 12 via the frame 30 with a plurality of screws 41 (see FIG. 7).

[0059] The frame 30 is provided between the substrate 24 and the bracket 12 and is fixed to the bracket 12. The frame 30 has an arch shape overall. The frame 30 supports the substrate 24 so that the optical module 23 faces the rotating plate 22 (more specifically, the area of ​​the rotating plate 22 on which a predetermined pattern is formed). The substrate 24 is fixed to the frame 30 by a predetermined fixing means. In this embodiment, the substrate 24 is fixed to the frame 30 by screws 42 (see FIG. 7 ) and an adhesive (not shown), but this is not limiting.

[0060] As shown in FIGS. 2A and 2B , the frame 30 has a frame main body 31 extending along the main surface 13 of the bracket 12, a first end 32 provided at one end thereof, and a second end 33 provided at the other end thereof. The first end 32 and the second end 33 are each received in a plurality of recesses 14 formed in the main surface 13 of the bracket 12. That is, in this embodiment, the first end 32 is received in one of the two recesses 14, and the second end 33 is received in the other of the two recesses 14. That is, the first end 32 is received in one of the plurality of recesses 14, and the second end 33 is received in the other of the plurality of recesses 14, different from the one recess 14 in which the first end 32 is received. A first alignment hole 32 a is formed in the first end 32. A second alignment hole 33 a is formed in the second end 33.

[0061] In this embodiment, the first alignment hole 32a and the second alignment hole 33a are each a circular through-hole that penetrates the first end 32 and the second end 33 in the thickness direction (the up-down direction in FIG. 1 ), but this is not limited thereto. The diameters of the first alignment hole 32a and the second alignment hole 33a are equal to each other, but this is not limited thereto. The inner surfaces of the first alignment hole 32a and the second alignment hole 33a are smooth, but this is not limited thereto. As shown in FIG. 2B , the first alignment hole 32a and the second alignment hole 33a are arranged symmetrically with respect to the rotation axis O when viewed from the rotation axis direction, but this is not limited thereto.

[0062] 1, when viewed from a direction perpendicular to the rotation axis O, the surfaces of the first end 32 and the second end 33 facing away from the bracket 12 (top surfaces in FIG. 1) overlap the main surface 13 of the bracket 12. However, when viewed from a direction perpendicular to the rotation axis O, the top surfaces may be offset from the main surface 13 of the bracket 12. Furthermore, although not shown, the top surfaces may be located between the two bearings 19 when viewed from a direction perpendicular to the rotation axis O.

[0063] The first end 32 and the second end 33 are located closer to the motor body 11 in the rotational axis direction (lower in FIG. 1 ) than the frame main body 31. The first end 32 is connected to the frame main body 31 via a first bridge portion 34 that extends in the rotational axis direction. The second end 33 is connected to the frame main body 31 via a second bridge portion 35 that also extends in the rotational axis direction. The frame main body 31, the first end 32, the second end 33, and the first bridge portion 34 and the second bridge portion 35 are integrally formed with one another.

[0064] The frame main body 31 is formed with at least one through hole 31a (three in this example) through which a screw 41 is inserted for fixing the substrate 24 and the frame 30 to the bracket 12. The frame main body 31 also is formed with at least one screw hole 31b (one in this example) into which a screw 42 is threadedly engaged for fixing the substrate 24 to the frame 30, and with an adhesive pin 31c used to bond the substrate 24 and the frame 30 together.

[0065] (Method of Manufacturing Motor with Encoder) Next, a method of manufacturing the motor with encoder 10 of this embodiment (hereinafter also simply referred to as the manufacturing method) will be described with reference to FIGS. 3 to 7. FIG. 3 is a perspective view that schematically shows the master equipment 50 of the first embodiment. FIG. 4 is a perspective view that shows the frame 30 placed on the master equipment 50 using a jig 60. FIG. 5 is a perspective view that shows the board 24 fixed to the frame 30 placed on the master equipment 50. FIG. 6 is a perspective view that schematically shows the motor assembly A of the first embodiment. FIG. 7 is a perspective view that shows the frame 30 to which the board 24 is fixed attached to the motor assembly A using the jig 60.

[0066] The manufacturing method includes a first preparation step, a second preparation step, a third preparation step, a fourth preparation step, a fifth preparation step, a first placement step, a fixing step, and a second placement step. The order of execution of the steps is not limited by the names or the order of description, and can be set arbitrarily as long as the motor 10 can be manufactured.

[0067] The first preparation step is a step of preparing the above-described frame 30. Note that instead of the frame 30, a frame having a first end portion in which a first alignment hole is formed and a second end portion in which a second alignment hole is formed (for example, a frame in which only alignment holes 32 a, 33 a are formed at both ends of a frame main body portion 31 extending along the main surface 13 of the bracket 12) may be prepared.

[0068] The second preparation step is a step of preparing a master facility 50 having a master body 51, a master shaft 54, and a master rotating plate 55, as shown in FIG. 3 . The master body 51 has a master main surface 52 on which the frame body portion 31 can be mounted. A plurality of (two in this example) master recesses 53 are formed in the master main surface 52. The master shaft 54 ​​is rotatable relative to the master body 51. The diameter of the master shaft 54 ​​is equal to the diameter of the shaft 18 of the motor 10. The master rotating plate 55 is rotatable together with the master shaft 54. The master shaft 54 ​​and the master rotating plate 55 have the same configuration as the shaft 18 and rotating plate 22 of the motor 10. For example, the master rotating plate 55 has a predetermined pattern formed thereon that is the same as that of the rotating plate 22 of the motor 10.

[0069] The third preparation step is a step of preparing a jig 60 (see FIG. 4 ) having a first alignment pin 61, a second alignment pin 62, and a cylindrical portion 63 formed with a shaft hole 64 through which the master shaft 54 ​​can be inserted. The first alignment pin 61 and the second alignment pin 62 correspond to the first alignment hole 32 a and the second alignment hole 33 a, respectively, of the frame 30. The first alignment pin 61 and the second alignment pin 62 are each connected to the cylindrical portion 63 via an arm plate 65.

[0070] The fourth preparation step is a step of preparing the above-described substrate 24. Note that instead of the substrate 24, a different type of substrate applicable to the encoder 20 (for example, a substrate having a shape different from that of the above-described substrate 24) may be prepared.

[0071] The fifth preparation step is to prepare a motor assembly A including a bracket 12, a shaft 18, and a rotating plate 22 (see FIG. 6). These components of the motor assembly A are the same as the components of the motor 10 described above. The positional relationship between the shaft 18 and the rotating plate 22 is the same as the positional relationship between the master shaft 54 ​​and the master rotating plate 55 in the master equipment 50. This positional relationship is when viewed from the direction of the rotation axis.

[0072] As shown in FIG. 4 , the first placement process is a process of placing the frame 30 in a predetermined positional relationship with respect to the master equipment 50. Specifically, the first placement process is a process of inserting the master shaft 54 ​​of the master equipment 50 into the shaft hole 64 of the jig 60, and inserting the first alignment pin 61 and the second alignment pin 62 of the jig 60 into the first alignment hole 32 a and the second alignment hole 33 a of the frame 30. In this manner, in the first placement process, the frame 30 is fixed in a predetermined positional relationship with respect to the master equipment 50. The first placement process is performed with at least a portion of each of the first end 32 and the second end 33 of the frame 30 housed in a different one of the multiple master recesses 53. That is, in this embodiment, the first placement process is performed with the first end 32 housed in one of the two master recesses 53 and the second end 33 housed in the other of the two master recesses 53. In other words, the first placement process is performed with the first end 32 accommodated in one of the multiple master recesses 53, and the second end 33 accommodated in another of the multiple master recesses 53 that is different from the one master recess 53 in which the first end 32 is accommodated.

[0073] 5, the fixing step is a step of adjusting and fixing the position of the substrate 24 to the frame 30 fixed to the master facility 50. At this time, the position of the optical module 23 fixed to the substrate 24 may be adjusted with respect to the master rotating plate 55 of the master facility 50. The position adjustment of the optical module 23 is performed by adjusting the position of the substrate 24 to which it is fixed along the main surface 13 of the frame 30. The position adjustment of the optical module 23 is also performed while checking the electrical signal output by the light receiving element of the optical module 23 when the master shaft 54 ​​and the master rotating plate 55 are rotated.

[0074] As shown in FIG. 7 , the second placement process is a process of placing the frame 30, to which the substrate 24 is fixed, relative to the motor assembly A using a jig 60. Specifically, the second placement process is a process of inserting the shaft 18 of the motor assembly A into the shaft hole 64 of the jig 60, and inserting the first alignment pin 61 and the second alignment pin 62 of the jig 60 into the first alignment hole 32 a and the second alignment hole 33 a of the frame 30. By doing so, in the second placement process, the frame 30 to which the substrate 24 is fixed is placed in the above-mentioned predetermined positional relationship with respect to the motor assembly A. In other words, in the second placement process, the positional relationship between the frame 30 and the master facility 50 achieved in the first placement process (or the positional relationship between the substrate 24 and the master facility 50 achieved in the fixing process) is reproduced between the frame 30 to which the substrate 24 is fixed and the motor assembly A. By doing so, in the second placement process, the optical module 23 fixed to the substrate 24 can be positioned. The second positioning step is performed with at least a portion of each of the first end 32 and the second end 33 of the frame 30 housed in a different recess 14 among the plurality of recesses 14. That is, in the present embodiment, the second positioning step is performed with the first end 32 housed in one of the two recesses 14 and the second end 33 housed in the other of the two recesses 14. That is, the second positioning step is performed with the first end 32 housed in one recess 14 among the plurality of recesses 14 and the second end 33 housed in another recess 14 among the plurality of recesses 14 that is different from the one recess 14 in which the first end 32 is housed.

[0075] Second Embodiment A second embodiment of the present disclosure will be described with reference to FIGS. 8A, 8B, and 9. FIG. 8A is a schematic perspective view of a frame 301 of the second embodiment, illustrating an image of a first alignment pin 611 and a second alignment pin 621. FIG. 8B is a schematic side cross-sectional view of the frame 301 of the second embodiment, illustrating how the frame 301 is biased. FIG. 9 is a schematic plan view of the frame 301 and the substrate 24 of the second embodiment. The motor of this embodiment differs from the frame 30 of the first embodiment in the configuration of the frame 301 and the like. The following mainly describes the differences from the first embodiment.

[0076] As shown in FIG. 8A , the frame 301 has a frame main body 31, a first end 321 provided on one end side of the frame main body 31, and a second end 331 provided on the other end side. A first alignment hole 321a is formed in the first end 321. A second alignment hole 331a is formed in the second end 331. The diameter of the first alignment hole 321a is smaller than the diameter of the second alignment hole 331a. Furthermore, at least a portion (in this example, the entirety) of the inner surface of the first alignment hole 321a is tapered toward the bracket 12. Furthermore, the surface of the frame 301 of this embodiment facing the bracket 12 (the lower surface in FIG. 8A ) is entirely flush.

[0077] In this embodiment, the first alignment pin 611 of the jig 601 has a tapered portion 61a at its tip. The taper angle of the tapered portion 61a may be the same as the taper angle of the tapered surface of the first alignment hole 321a. The tapered portion 61a is configured to fit into the first alignment hole 321a with virtually no gap. Furthermore, the diameter of the second alignment pin 621 of the jig 601 is smaller than the inner diameter of the second alignment hole 331a. Therefore, when the second alignment pin 621 enters the second alignment hole 331a, a certain amount of gap is formed between them.

[0078] 8B , the first positioning step, the fixing step, and the second positioning step are performed in a state in which a biasing means (not shown) is used to bias the second end 331 corresponding to the second alignment hole 331a of the frame 301 in a predetermined direction (leftward in the figure). This allows each of these steps to be performed in a state in which a predetermined portion of the inner surface of the second alignment hole 331a is in contact with the second alignment pin 621, thereby improving the positioning accuracy of the optical module 23.

[0079] 9 , when viewed from the rotation axis direction, the first distance D1 between the first alignment hole 321a and the optical module 23 is smaller than the second distance D2 between the second alignment hole 331a and the optical module 23 (D1<D2). As a result, even if a positioning error occurs on the side of the second alignment hole 331a, which has a relatively large diameter, in the first placement step, the fixing step, and the second placement step, it is possible to suppress a decrease in the positioning accuracy of the optical module 23 due to the error.

[0080] Third Embodiment A third embodiment of the present disclosure will be described with reference to Fig. 10. Fig. 10 is a perspective view schematically showing a frame 302 of the third embodiment. In the motor of this embodiment, the configuration of the frame 302 differs from the configuration of the frame 30 of the first embodiment. The following mainly describes the differences from the first embodiment.

[0081] As shown in FIG. 10 , the frame 302 includes a frame main body 31, a first end 322 at one end thereof, and a second end 332 at the other end thereof. A first alignment hole 32a is formed in the first end 322. A second alignment hole 332a is formed in the second end 332. In this embodiment, the first alignment hole 32a is circular, while the second alignment hole 332a is oval. More specifically, the second alignment hole 332a is oval and extends in the radial direction. Although not shown, the first and second alignment pins of the jig each have a circular cross-sectional shape. This allows the first placement process, the fixing process, and the second placement process to be performed while allowing for radial manufacturing errors of the jig and the frame 302 itself. The second alignment hole 332a may also be oval and extend in a direction other than the radial direction.

[0082] <<Supplementary Note>> The above description of the embodiment discloses the following techniques.

[0083] (Technology 1) An encoder of Technology 1 includes a boss that rotates around the rotation axis of a shaft of a motor that includes a bracket and a shaft, and a rotating plate fixed to the boss and rotating around the rotation axis. The encoder of Technology 1 also includes an optical module having a light source that irradiates light onto the rotating plate and a light-receiving element that receives light reflected from or transmitted through the rotating plate, a substrate to which the optical module is fixed, and a frame provided between the substrate and the bracket. The bracket has a main surface facing the frame. The frame has a frame main body extending along the main surface, a first end portion provided on one end of the frame main body and having a first alignment hole formed therein, and a second end portion provided on the other end of the frame main body and having a second alignment hole formed therein.

[0084] (Technology 2) In an encoder of Technology 2, in the encoder described in Technology 1, a plurality of recesses are formed in the main surface of the bracket. At least a portion of the first end is accommodated in one of the plurality of recesses, and at least a portion of the second end is accommodated in another of the plurality of recesses that is different from the one recess in which the first end is accommodated. The inner surfaces of the first alignment hole and the second alignment hole are each smooth.

[0085] (Technology 3) In the encoder of Technology 3, in the encoder according to Technology 1 or 2, at least a part of the inner surface of the first alignment hole is a tapered surface that becomes thinner as it approaches the bracket.

[0086] (Technology 4) In the encoder of Technology 4, in the encoder according to any one of Technologies 1 to 3, the diameter of the first alignment hole is smaller than the diameter of the second alignment hole.

[0087] (Technology 5) In the encoder of Technology 5, in the encoder described in Technology 4, the distance between the first alignment hole and the optical module is smaller than the distance between the second alignment hole and the optical module when viewed from the direction in which the rotation axis extends.

[0088] (Technology 6) In the encoder of Technology 6, in the encoder described in any one of Technologies 1 to 5, the first alignment hole is formed in a circular shape, and the second alignment hole is formed in an oval shape.

[0089] (Technology 7) In the encoder of Technology 7, in the encoder described in any one of Technologies 1 to 6, the first alignment hole and the second alignment hole are arranged symmetrically with respect to the rotation axis when viewed from the direction in which the rotation axis extends.

[0090] (Technology 8) A motor with an encoder of Technology 8 includes the encoder according to any one of Technologies 1 to 7, a motor body having a bracket to which a frame is attached, a shaft attached to a boss, and two bearings that rotatably support the shaft.

[0091] (Technology 9) In a motor with an encoder of Technology 9, in the motor with an encoder described in Technology 8, when viewed from a direction perpendicular to the rotation axis, the surfaces of the first end and second end facing away from the bracket overlap with the main surface of the bracket.

[0092] (Technology 10) In a motor with an encoder according to Technology 10, in the motor with an encoder described in Technology 8, when viewed from a direction perpendicular to the rotation axis, the surfaces of the first end and the second end facing away from the brackets are located between the two bearings.

[0093] (Technology 11) A method for manufacturing a motor with an encoder of Technology 11 includes a first preparation step of preparing a frame having a frame main body, a first end portion on one end of the frame main body and having a first alignment hole formed therein, and a second end portion on the other end of the frame main body and having a second alignment hole formed therein. The method for manufacturing a motor with an encoder of Technology 11 also includes a second preparation step of preparing a master facility having a master main body on which the frame main body can be mounted, a master shaft rotatable relative to the master main body, and a master rotating plate rotatable together with the master shaft. The method for manufacturing a motor with an encoder of Technology 11 also includes a third preparation step of preparing a jig having first and second alignment pins corresponding to the first and second alignment holes, respectively, and a cylindrical portion having a shaft hole through which the master shaft can be inserted. The method for manufacturing a motor with an encoder of Technology 11 also includes a fourth preparation step of preparing a substrate on which an optical module having a light source and a light receiving element is fixed. Furthermore, a manufacturing method for a motor with an encoder of Technology 11 includes a fifth preparation step of preparing a motor assembly including a bracket having a main surface on which a frame main body can be mounted, a shaft, and a rotating plate, wherein the positional relationship between the shaft and the rotating plate is the same as the positional relationship between the master shaft and the master rotating plate. The manufacturing method for a motor with an encoder of Technology 11 also includes a first placement step of inserting a master shaft of a master facility into a shaft hole of a jig and inserting first and second alignment pins of the jig into first and second alignment holes of the frame, thereby placing the frame in a predetermined positional relationship with the master facility. The manufacturing method for a motor with an encoder of Technology 11 also includes a fixing step of adjusting the position of a substrate with respect to the frame placed on the master facility and fixing it.Furthermore, the manufacturing method of a motor with an encoder of Technology 11 includes a second positioning step, which is a step of positioning the frame to which the substrate is fixed relative to the motor assembly using a jig, in which the shaft of the motor assembly is inserted into the shaft hole of the jig and the first alignment pin and second alignment pin of the jig are inserted into the first alignment hole and second alignment hole of the frame, thereby positioning the frame to which the substrate is fixed in a predetermined positional relationship relative to the motor assembly.

[0094] (Technical Field 12) In a method for manufacturing a motor with an encoder according to Technical Field 12, in the method for manufacturing a motor with an encoder according to Technical Field 11, a plurality of master recesses are formed on a surface of the master body on which the frame main body portion can be placed, and a plurality of recesses are formed on a main surface of the bracket. Furthermore, the first arranging step is performed with at least a portion of each of the first end and second end of the frame housed in a different one of the plurality of master recesses. The second arranging step is performed with at least a portion of each of the first end and second end of the frame housed in a different one of the plurality of recesses.

[0095] The present disclosure can be used for an encoder, a motor with an encoder, and a method for manufacturing a motor with an encoder.

[0096] REFERENCE SIGNS LIST 10 Motor (motor with encoder) 11 Motor body 12 Bracket 13 Main surface 14 Recess 15 Case 16 Rotor 17 Stator 18 Shaft 19 Bearing 20 Encoder 21 Boss 22 Rotating plate 23 Optical module 24 Substrate 30 Frame 31 Frame body portion 31a Through hole 31b Screw hole 31c Adhesive pin 32 First end 32a First alignment hole 33 Second end 33a Second alignment hole 34 First bridge portion 35 Second bridge portion 41 Screw 42 Screw 50 Master fixture 51 Master body 52 Master main surface 53 Master recess 54 Master shaft 55 Master rotating plate 60 Jig 61 First alignment pin 61a Tapered portion 62 Second alignment pin 63 Cylindrical portion 64 Shaft hole 65 Arm plate 301 Frame 302 Frame 321 First end 321a First alignment hole 322 First end 331 Second end 331a Second alignment hole 332 Second end 332a Second alignment hole 601 Jig 611 First alignment pin 621 Second alignment pin A Motor assembly D1 First distance D2 Second distance O Rotation axis

Claims

1. An encoder comprising: a boss that rotates around the rotation axis of a shaft of a motor having a bracket and a shaft; a rotating plate fixed to the boss and rotating around the rotation axis; an optical module having a light source that irradiates light onto the rotating plate and a light receiving element that receives light reflected from or transmitted through the rotating plate; a substrate to which the optical module is fixed; and a frame provided between the substrate and the bracket, wherein the bracket has a main surface facing the frame, and the frame has: a frame main body portion extending along the main surface; a first end portion provided on one end of the frame main body portion and having a first alignment hole formed therein; and a second end portion provided on the other end of the frame main body portion and having a second alignment hole formed therein.

2. An encoder as described in claim 1, wherein a plurality of recesses are formed in the main surface of the bracket, at least a portion of the first end is accommodated in one of the plurality of recesses, and at least a portion of the second end is accommodated in another of the plurality of recesses that is different from the one recess in which the first end is accommodated, and the inner surfaces of the first alignment hole and the second alignment hole are each smooth.

3. The encoder according to claim 1 or 2, wherein at least a portion of the inner surface of the first alignment hole is a tapered surface that becomes narrower as it approaches the bracket.

4. An encoder according to claim 1 or 2, wherein the diameter of the first alignment hole is smaller than the diameter of the second alignment hole.

5. The encoder according to claim 4, wherein the distance between the first alignment hole and the optical module is smaller than the distance between the second alignment hole and the optical module when viewed in the direction in which the rotation axis extends.

6. The encoder according to claim 1 or 2, wherein the first alignment hole is formed in a circular shape, and the second alignment hole is formed in an oval shape.

7. The encoder according to claim 1 or 2, wherein the first alignment hole and the second alignment hole are arranged symmetrically with respect to the rotation axis when viewed from the direction in which the rotation axis extends.

8. A motor with an encoder, comprising: the encoder according to claim 1 or 2; a motor body having the bracket to which the frame is attached; the shaft attached to the boss; and two bearings that rotatably support the shaft.

9. A motor with an encoder as described in claim 8, wherein, when viewed from a direction perpendicular to the rotation axis, the surfaces of the first end and the second end facing away from the bracket overlap with the main surface of the bracket.

10. A motor with an encoder as described in claim 8, wherein the surfaces of the first end and the second end facing away from the bracket when viewed from a direction perpendicular to the rotation axis are located between the two bearings.

11. A first preparation step of preparing a frame having a frame main body, a first end provided on one end side of the frame main body and having a first alignment hole formed therein, and a second end provided on the other end side of the frame main body and having a second alignment hole formed therein; a second preparation step of preparing a master facility having a master main body on which the frame main body can be placed, a master shaft rotatable relative to the master main body, and a master rotating plate rotatable together with the master shaft; a third preparation step of preparing a jig having first and second alignment pins corresponding to the first and second alignment holes, respectively, and a cylindrical portion having a shaft hole through which the master shaft can be inserted; a fourth preparation step of preparing a substrate to which an optical module having a light source and a light receiving element is fixed; and a fifth preparation step of preparing a motor assembly comprising: a bracket having a main surface on which the frame main body can be placed, a shaft, and a rotating plate, wherein the positional relationship between the shaft and the rotating plate is the same as the positional relationship between the master shaft and the master rotating plate. a first positioning step of inserting the master shaft of the master equipment into the shaft hole of the jig and inserting the first alignment pin and the second alignment pin of the jig into the first alignment hole and the second alignment hole of the frame, thereby positioning the frame in a predetermined positional relationship with respect to the master equipment; a fixing step of adjusting the position of the substrate with respect to the frame placed on the master equipment and fixing it; and a second positioning step of using the jig to position the frame with the substrate fixed to the motor assembly, wherein the frame with the substrate fixed is positioned in the predetermined positional relationship with respect to the motor assembly by inserting the shaft of the motor assembly into the shaft hole of the jig and inserting the first alignment pin and the second alignment pin of the jig into the first alignment hole and the second alignment hole of the frame.

12. A method for manufacturing a motor with an encoder as described in claim 11, wherein a plurality of master recesses are formed on a surface of the master body on which the frame main body portion can be placed, a plurality of recesses are formed on the main surface of the bracket, the first placement step is performed with at least a portion of each of the first end and second end of the frame housed in a different one of the plurality of master recesses, and the second placement step is performed with at least a portion of each of the first end and second end of the frame housed in a different one of the plurality of recesses.

Images