Encoder and motor equipped with it

Abstract

The optical module is stably held in place. The disclosed encoder comprises: a rotating plate that rotates about a rotation axis; an optical module (22) comprising at least one of 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 (23) on which the optical module (22) is disposed; and a frame that supports the substrate. The substrate (23) has a first mounting hole (23a) and a second mounting hole (23b) and is screwed to the frame by a first screw inserted into the first mounting hole (23a) and a second screw inserted into the second mounting hole (23b). Viewed from the direction along the rotation axis, the optical module (22) is disposed on a first line segment (L1) connecting the center of the first mounting hole (23a) and the center of the second mounting hole (23b).

Description

Technical Field

[0001] This disclosure relates to encoders and motors having the same. Background Technology

[0002] Previously, encoders for detecting the rotational position of a motor shaft were known (e.g., Patent Document 1). The encoder disclosed in Patent Document 1 includes: a rotating plate mounted on the shaft and having a given pattern; and a main body having a detector for detecting the given pattern. This main body is fixed to a given object in a fixed position that is linearly symmetrical about a virtual straight line connecting the center of the detector and the center of the shaft when viewed from the axial direction of the shaft.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: JP 2014-211347 Summary of the Invention

[0006] However, in the encoder of Patent Document 1, the stress caused by fixing acts unevenly on the detector, which may cause the detector to remain in an unstable state (e.g., a tilted state). If the detector (or optical module) is held in such an unstable state, the detection accuracy of the encoder will decrease. Under such circumstances, one of the objectives of this disclosure is to stably hold the optical module.

[0007] This disclosure relates to an encoder. The encoder comprises: a rotating plate that rotates about a rotation axis; an optical module including at least one of a light source for irradiating the rotating plate and a light-receiving element for receiving light reflected from or transmitted through the rotating plate; a substrate on which the optical module is disposed; and a frame supporting the substrate. The substrate has a first mounting hole and a second mounting hole, and is screwed to the frame by a first screw inserted into the first hole and a second screw inserted into the second hole. Viewed along the rotation axis, the optical module is disposed on a first line segment connecting the center of the first mounting hole and the center of the second mounting hole.

[0008] Another situation covered in this disclosure relates to an electric motor. The motor has a bracket, a shaft passing through the bracket, and the aforementioned encoder. The shaft is mounted to the rotating plate and rotates together with the rotating plate. The base plate and the frame are fixed to the bracket together by the screws.

[0009] According to this disclosure, the optical module can be stably maintained. Attached Figure Description

[0010] Figure 1This is a simplified cross-sectional view of the motor involved in Embodiment 1.

[0011] Figure 2 This is a schematic diagram of the substrate of the motor according to Embodiment 1 as viewed from the rotating plate.

[0012] Figure 3 This is a schematic diagram of the motor according to Embodiment 1, viewed from the housing frame.

[0013] Figure 4 This is a schematic diagram of the substrate of the motor according to Embodiment 2 as viewed from the rotating plate.

[0014] Figure 5 This is a diagram showing the upper surface of the rotating plate of the motor according to Embodiment 1 as viewed from the substrate.

[0015] Figure 6 This is a cross-sectional view schematically showing the arrangement of the optical module, substrate, and rotating plate in the motor according to Embodiment 1.

[0016] Figure 7 This is a top view showing the configuration of the light source and light-receiving element of the optical module of the motor according to Embodiment 1.

[0017] Figure 8 This is a top view showing the configuration of the light source and light-receiving element in Example 1 of another configuration of the optical module of the motor according to Embodiment 1.

[0018] Figure 9 This is a top view showing the configuration of the light source and light-receiving element in Example 2, which illustrates another configuration of the optical module of the motor according to Embodiment 1.

[0019] Figure 10 This is a top view showing the configuration of the light source and light-receiving element in Example 3, which illustrates another configuration of the optical module of the motor according to Embodiment 1.

[0020] Figure 11 This is a cross-sectional view schematically illustrating the arrangement of the optical module, substrate, and rotating plate in a modified example 1 of the motor according to Embodiment 1.

[0021] Figure 12 This is a cross-sectional view schematically illustrating the arrangement of the optical module, substrate, and rotating plate in a modified example 2 of the motor according to embodiment 1. Detailed Implementation

[0022] The following examples illustrate the implementation of the encoder and motor involved in this disclosure. However, this disclosure is not limited to the examples described below. In the following description, specific values ​​and materials are sometimes illustrated, but other values ​​and materials may be used as long as the effects of this disclosure can be achieved.

[0023] (encoder)

[0024] The encoder disclosed herein includes a rotary plate, an optical module, a base plate, and a frame.

[0025] The rotating plate rotates around a rotating axis. The rotating plate can be mounted on the shaft of the motor. The rotating plate can be directly mounted to the shaft or indirectly mounted. In the latter case, the rotating plate is fixed to a boss attached to the shaft. The rotating plate rotates together with the shaft around its axis of rotation. The rotating plate has a given pattern formed along its circumference. The given pattern can be used to detect the rotational position of the shaft, or it can be used to detect both the rotational position and the rotational speed of the shaft. Here, the rotational position of the shaft refers to its relative angular position or absolute angular position, and the rotational speed of the shaft refers to the number of rotations of the shaft.

[0026] The optical module includes at least one of a light source that illuminates a rotating plate and a light-receiving element. The light-receiving element receives light that is irradiated by the light source and reflected by the rotating plate (reflected light) or light that is transmitted through the rotating plate (transmitted light). When the light-receiving element receives reflected light, both the light source and the light-receiving element are disposed on one side of the rotating plate. Conversely, when the light-receiving element receives transmitted light, one of the light source and the light-receiving element is disposed on one side of the rotating plate, and the other is disposed on the other side. The light-receiving element can convert the received light into an electrical signal. This electrical signal can be used to determine the rotational position and speed of the shaft.

[0027] Optical modules are mounted on the substrate. Various electronic components can be mounted on the substrate. The substrate can be substantially circular. "Substantially circular" means, for example, a plate whose outer edge is more than 80% circular.

[0028] The frame houses the rotating plate and supports the substrate, such that the optical module is positioned opposite the rotating plate. The frame and substrate can be fixed to each other by a given fixing unit. The frame can be substantially cylindrical. In other words, the frame can have an internal cylindrical space with a diameter larger than that of the rotating plate. The axis of rotation of the rotating plate is coaxial with the cylindrical space. The outer diameter of the frame can be equal to or different from the outer diameter of the substrate.

[0029] Here, the aforementioned substrate has a first mounting hole and a second mounting hole through which screws are inserted to fix the substrate and the frame in a mutually positioned state. Furthermore, viewed from the direction of rotation along the axis of rotation of the rotating plate, the aforementioned optical module is positioned on a first line segment connecting the center of the first mounting hole and the center of the second mounting hole. The term "optical module positioned on the first line segment" means that, viewed from the direction of rotation along the axis of rotation of the rotating plate, at least a portion of the optical module overlaps with the first line segment. With this configuration, stress is applied substantially uniformly to the optical module by inserting screws through the first and second mounting holes. Therefore, tilting of the optical module can be prevented, thereby holding it stably.

[0030] Viewed along the rotation axis of the rotating plate, the optical module can be approximately rectangular and divided into a first region and a second region by a first line segment. The ratio of the area of ​​the first region to the area of ​​the second region can be 1:1 to 1:2. Furthermore, the ratio of the area of ​​the first region to the area of ​​the second region can also be 1:1. By setting the ratio of the area of ​​the first region to the area of ​​the second region in this way, the tilting of the optical module can be further suppressed. In addition, the term "approximately rectangular" includes not only a rectangular shape but also shapes with rounded corners, etc.

[0031] Viewed from the direction of rotation along the axis of rotation of the rotating plate, the optical module can be positioned to overlap with the midpoint of the first line segment. Here, "positioned to overlap with the midpoint of the first line segment" means that, viewed from the direction of rotation along the axis of rotation of the rotating plate, at least a portion of the optical module overlaps with that midpoint. This configuration further suppresses tilting of the optical module.

[0032] The substrate may also have a third mounting hole. The first, second, and third mounting holes can be configured in a rotationally asymmetrical position about the rotation axis of the rotating plate. According to this structure, the relative positions of the substrate, frame, and mounting object are determined in the circumferential direction of the rotating plate by the corresponding screw holes of the first to third mounting holes and the mounting object (e.g., bracket) of the substrate. Therefore, omissions in encoder assembly can be prevented. Alternatively, the first to third mounting holes can also be configured in a rotationally symmetrical position about the rotation axis of the rotating plate.

[0033] When observing the substrate along the rotation axis of the rotating plate, the first line segment, the second line segment connecting the center of the first mounting hole and the center of the third mounting hole, and the third line segment connecting the center of the second mounting hole and the center of the third mounting hole can be configured as an isosceles triangle with a base angle larger than the apex angle and the first line segment as the base. According to this structure, the stress acting on the optical module is further homogenized, and the tilting of the optical module can be further suppressed. Furthermore, the optical module can be positioned far from the rotation axis of the rotating plate, and a given pattern opposite to the optical module can be formed near the outer edge of the rotating plate. Since the given pattern is easily formed near the outer edge of the rotating plate, the encoder can be easily manufactured.

[0034] The frame can have three through holes, each located at a position corresponding to the first to third mounting holes, through which screws are inserted. In the radial direction of the rotating plate, the difference between the inner dimension of the frame and the outer dimension of the rotating plate (difference A) can be greater than the difference between the inner dimensions (or inner diameter if each through hole is circular) of the three through holes and the outer dimension of the screw shaft (hereinafter also referred to as difference D). Here, during encoder assembly, when fine-tuning the relative position of the optical module with respect to the rotating plate, the positions of the substrate and frame for mounting the optical module are fine-tuned. During this fine-tuning, since the screw shaft is inserted through the through holes of the frame, in the radial direction of the rotating plate, the frame (as well as the substrate and optical module) can only move within a range that prevents the screw shaft from contacting the inner surface of the through holes. Furthermore, due to the aforementioned relationship between difference A and difference D, even if the frame moves to its maximum extent within this range, the inner surface of the frame will not contact the outer edge of the rotating plate. Therefore, during encoder assembly, damage to the rotating plate due to contact with the frame can be suppressed.

[0035] In the radial direction of the rotating plate, the difference between the inner dimension (or inner diameter) of the frame and the outer dimension (or outer diameter) of the rotating plate (hereinafter also referred to as dimension difference A) is greater than the difference between the inner dimensions (or inner diameter if each mounting hole is circular) of the first and second mounting holes and the outer dimension (or outer diameter) of the screw shaft (hereinafter also referred to as dimension difference C). Here, when fine-tuning the relative position of the optical module with respect to the rotating plate during encoder assembly, the position of the substrate and frame on which the optical module is mounted is fine-tuned. During this fine-tuning, since the screw shaft is inserted into the mounting hole of the substrate, the substrate (as well as the frame and optical module) can only move within a range in the radial direction of the rotating plate where the screw shaft does not contact the inner edge of the mounting hole. Furthermore, due to the relationship between the magnitudes of dimension difference A and dimension difference C, even if the substrate is moved to its maximum extent within this range, the inner surface of the frame does not contact the outer edge of the rotating plate. Therefore, damage to the rotating plate due to contact with the frame can be suppressed during encoder assembly, etc.

[0036] (Electric motor)

[0037] The motor disclosed herein includes a bracket, a shaft, and the aforementioned encoder. The motor may include: a rotor mounted on the shaft; and a stator opposed to the rotor with a gap. The motor may be, for example, an internal rotor type three-phase synchronous motor, but is not limited thereto.

[0038] The bracket is the component for mounting the encoder. The encoder base plate and frame are secured to the bracket together with screws.

[0039] The shaft passes through the bracket. The shaft is mounted to the encoder's rotating plate and rotates together with the rotating plate.

[0040] As described above, according to this disclosure, the optical module can be stably maintained, and the reduction in the detection accuracy of the encoder can be avoided.

[0041] Hereinafter, an example of the encoder and motor involved in this disclosure will be specifically described with reference to the accompanying drawings. The components of the encoder and motor described below can utilize the components described above. The components of the encoder and motor described below can be modified based on the above description. Furthermore, the matters described below can also be applied to the above-described embodiments. Non-essential components of the encoder and motor involved in this disclosure may be omitted from the components of the encoder and motor described below. Additionally, the figures shown below are schematic and do not accurately reflect the actual shape, size, number, etc., of the components.

[0042] Implementation Method 1

[0043] Embodiment 1 of this disclosure is described. The motor 10 in this embodiment is an internal rotor type three-phase synchronous motor, but it is not limited thereto.

[0044] Figure 1 This is a schematic cross-sectional view of the motor 10 according to this embodiment. Figure 1 As shown, the motor 10 includes a shaft 12, a rotor 15, a stator 16, a housing 17, and an encoder 20 with a bracket 11.

[0045] The shaft 12 passes through the bracket 11 and is rotatably supported in the bracket 11 via the bearing 13. A rotating plate 21 (described later) with an encoder 20 is mounted on the shaft 12, and the rotating plate 21 rotates together with the shaft 12.

[0046] The rotor 15 is mounted on the shaft 12. The rotor 15 and the shaft 12 rotate together. The rotor 15 in this embodiment is a rotor with embedded magnets, but it is not limited to this.

[0047] The stator 16 and rotor 15 are positioned opposite each other with an air gap between them. The stator 16 is located radially outside the rotor 15 of the motor 10. The stator 16 in this embodiment is a stator with concentrated windings, but it is not limited to this.

[0048] The housing 17 is a hollow cylindrical component. The housing 17 is combined with the bracket 11 to house the rotor 15 and the stator 16. The stator 16 is fixed to the inner surface of the housing 17. The housing 17 contains a non-magnetic material (e.g., aluminum or an aluminum alloy). In this embodiment, the housing 17 and the bracket 11 are separate components, but they can also be integrally formed.

[0049] The encoder 20 in this embodiment is a multi-rotation absolute encoder, but it is not limited to this. The encoder 20 in this embodiment is a battery-powered encoder, but it can also be a battery-free encoder with permanent magnets and a power generation element. Figure 1 As shown, the encoder 20 includes a bracket 11, a rotating plate 21, an optical module 22, a base plate 23, and a frame 24. Alternatively, the encoder 20 may not include the bracket 11, in which case the bracket 11 is also a component of the motor 10.

[0050] The bracket 11 is a component for mounting the encoder 20 to the housing 17. A through hole is formed in the center of the bracket 11, through which the shaft 12 passes. In addition, a bearing 13 that rotatably supports the shaft 12 is fixed to the inner surface of the through hole. The bracket 11 houses the rotor 15, the stator 16, and the housing 17 together.

[0051] The rotating plate 21 is mounted to the shaft 12 of the motor 10 via a boss 25. The outer shape of the rotating plate 21 is substantially circular. The boss 25 is fixed to the shaft 12 by bolts 26 inserted through its bolt holes 25a. The rotating plate 21 rotates together with the shaft 12, using the shaft 12's axis of rotation as its axis of rotation.

[0052] Figure 5 This is a diagram showing the upper surface of the rotating plate 21 of the motor 10 according to this embodiment, as viewed from the substrate 23. (See diagram below.) Figure 5 As shown, the rotating plate 21 has a given pattern 21p formed along its circumference. The given pattern 21p is used to detect the rotational position and rotational speed of the shaft 12. The given pattern 21p can be, for example, a barcode or a QR code (registered trademark).

[0053] Figure 6 This is a cross-sectional view schematically showing the arrangement relationship of the optical module 22, the substrate 23, and the rotating plate 21 of the motor 10 involved in this embodiment. Figure 7 This is a top view showing the configuration of the light source 22s and the light-receiving element 22r in the optical module 22. (See attached image.) Figure 6As shown, the optical module 22 includes: a light source 22s (e.g., an LED (light-emitting diode)) for irradiating light onto the rotating plate 21; and light-receiving elements 22r (e.g., photodiodes). Furthermore, there are multiple light-receiving elements 22r, each having a rectangular shape and arranged parallel to the long side of the rectangle. The optical module 22 extends from the direction along the rotation axis of the rotating plate 21 (… Figure 1 When observing in the vertical direction (hereinafter referred to as the axial direction), as explained below... Figure 7 As shown, it is roughly rectangular, but the shape is not particularly limited. "Roughly rectangular" includes not only a rectangular shape but also shapes with rounded corners. In this embodiment, the light-receiving element 22r receives light Lb irradiated from the light source 22s and reflected by the rotating plate 21. The light-receiving element 22r can also be configured to receive light irradiated from the light source 22s and transmitted through the rotating plate 21. When the light-receiving element 22r is configured to receive light transmitted through the rotating plate 21, in... Figure 1 In this configuration, the light source can be positioned below the rotating plate 21. The light-receiving element converts the received light into an electrical signal. This electrical signal is used to determine the rotational position and speed of the shaft 12. Furthermore, in... Figure 6 In the example shown, the optical module 22 has a structure with both a light source 22s and a light-receiving element 22r, but the optical module 22 may have either a light source 22s or a light-receiving element 22r. For example, the optical module 22 may have a light-receiving element 22r, and the light source 22s may be directly disposed on the substrate 23.

[0054] An optical module 22 is mounted on the substrate 23. In addition, various electronic components 27 are mounted on the substrate 23.

[0055] Figure 2 This is a schematic diagram of the base plate 23 in the motor 10 according to this embodiment, as viewed from the rotating plate 21. Figure 2 As shown, the substrate 23 is substantially circular and has a first mounting hole 23a, a second mounting hole 23b, and a third mounting hole 23c. The first mounting hole 23a to the third mounting hole 23c are, as shown... Figure 1 As shown in the portion with the third mounting hole 23c, a screw 14 (or bolt) for mounting the substrate 23 and the frame 24 together to the bracket 11 is inserted. The screw 14 fixes the substrate 23 and the frame 24 in a mutually positioned state. That is, the relative positional relationship between the screw 14 and the bracket 11 is fixed. The first mounting holes 23a to the third mounting holes 23c are substantially circular and pass through the substrate 23 in its thickness direction. The term "substantially circular" means, for example, a shape in which more than 80% of the outer edge is composed of arcs.

[0056] The optical module 22, viewed from the axial direction, is positioned at a location overlapping the midpoint M of the first line segment L1 connecting the centers of the first mounting hole 23a and the second mounting hole 23b. The optical module 22 is divided into a first region 22a and a second region 22b by the first line segment L1. The ratio of the area of ​​the first region 22a to the area of ​​the second region 22b is 1:1. In this embodiment, viewed from the axial direction, the center point (intersection of the two diagonals) of the rectangular optical module 22 coincides with the midpoint M of the first line segment L1. The optical module 22 is configured such that at least a portion of it overlaps with the first line segment L1 when viewed from the axial direction. This configuration suppresses tilting of the optical module 22, thereby maintaining its stability. The distance between the center point of the optical module 22 and the midpoint M of the first line segment L1 can, for example, be 5 mm or less.

[0057] The first line segment L1, the second line segment L2 connecting the center of the first mounting hole 23a and the center of the third mounting hole 23c, and the third line segment L3 connecting the center of the second mounting hole 23b and the center of the third mounting hole 23c form an isosceles triangle with a base angle larger than the vertex angle and the first line segment L1 as the base. Thus, the first mounting holes 23a to the third mounting holes 23c are positioned in a rotationally asymmetrical manner about the rotation axis of the rotating plate 21.

[0058] Frame 24 is fixed to bracket 11. Frame 24 is substantially cylindrical. Frame 24 houses rotating plate 21 and supports substrate 23 such that optical module 22 is opposed to rotating plate 21 (more specifically, the area of ​​rotating plate 21 with a given pattern). Substrate 23 is fixed in frame 24 by a given fixing unit. Specifically, substrate 23 is fixed in frame 24 by screws 14.

[0059] In addition, whenever the substrate 23 is fixed in the frame 24, for example, the two can be fixed to each other by pressing the pins of the frame 24 into the pin holes formed in the substrate 23.

[0060] Figure 3 This is a schematic diagram showing the motor 10 according to this embodiment, viewed from the housing 17 through the frame 24. Figure 3 As shown, the frame 24 has three through holes 24b for inserting the aforementioned screws 14. The three through holes 24b are located at positions corresponding to the first mounting holes 23a to the third mounting holes 23c of the substrate 23. The inner dimension D7 of each through hole 24b is substantially equal to, but may differ from, the inner dimension D6 of the first mounting holes 23a to the third mounting holes 23c of the substrate 23. Each through hole 24b extends the frame 24 in its thickness direction (… Figure 1 It runs through the vertical direction. The frame 24 and the base plate 23 are fixed to the bracket 11 by screws 14.

[0061] Here, bracket 11 is on the surface opposite to frame 24 ( Figure 1 The upper surface of the motor 10 has three recesses 11a. The three recesses 11a are recessed in the axial direction. The three recesses 11a are equally spaced (at 120° intervals) in the circumferential direction of the motor 10. Each recess 11a is substantially circular. The shape of each recess 11a can be any shape, such as ellipse, rectangle, or polygon.

[0062] The frame 24 has three protrusions 24a at positions corresponding to the three recesses 11a, which enter the recesses 11a of the bracket 11 through a gap (the radial gap of the rotating plate 21). The three protrusions 24a protrude in the axial direction. The three protrusions 24a are equally spaced (at 120° intervals) around the circumference of the frame 24. Each protrusion 24a is substantially circular. However, the shape of each protrusion 24a can be any shape, such as ellipse, rectangle, or polygon.

[0063] like Figure 1 As shown, in the radial direction of the rotating plate 21 ( Figure 1 In the left-right direction (hereinafter referred to as radial), the difference between the inner dimension D1 of the frame 24 and the outer dimension D2 of the rotating plate 21 (dimension difference A) is greater than the difference between the inner dimension D3 of the recess 11a of the bracket 11 and the outer dimension D4 of the protrusion 24a of the frame 24 (hereinafter referred to as dimension difference B). Dimension difference B is equivalent to the maximum movable distance of the protrusion 24a relative to the recess 11a. As an example, dimension difference A can be 2 mm or more and 3 mm or less, and dimension difference B can be 0.5 mm or more and 1.5 mm or less. In addition, the inner dimension D1 of the frame 24 is larger than the outer dimension D2 of the rotating plate 21 (D1 > D2), and the inner dimension D3 of the recess 11a is larger than the outer dimension D4 of the protrusion 24a (D3 > D4).

[0064] Furthermore, in the radial direction, the dimensional difference A is greater than the difference (dimensional difference C) between the inner dimension D6 of the first mounting hole 23a of the substrate 23 and the outer dimension D5 of the shaft portion of the screw 14. The dimensional difference C corresponds to the maximum value of the movable distance of the substrate 23 relative to the screw 14. As an example, the dimensional difference C can be greater than 0.5 mm and less than 1.5 m. In addition, the inner dimension D6 of the first mounting hole 23a can be larger than the outer dimension D5 of the shaft portion of the screw 14 (D6>D5).

[0065] Furthermore, in the radial direction, the dimensional difference A is greater than the difference (dimensional difference D) between the inner dimension D7 of the through hole 24b of the frame 24 and the outer dimension D5 of the shaft portion of the screw 14. The dimensional difference D corresponds to the larger value of the movable distance of the frame 24 relative to the screw 14. As an example, the dimensional difference D can be greater than 0.5 mm and less than 1.5 mm. In addition, the inner dimension D7 of the through hole 24b is larger than the outer dimension D5 of the shaft portion of the screw 14 (D7 > D5).

[0066] By understanding the relationship between the size difference A and the size differences B to D described above, the following advantages can be obtained. Specifically, during the assembly of the encoder 20, when fine-tuning the relative position of the optical module 22 with respect to the rotating plate 21, the positions of the substrate 23 and frame 24 on which the optical module 22 is mounted can be fine-tuned. During this fine-tuning, the radial movement range of the frame 24 and substrate 23 relative to the rotating plate 21 is limited by physical interference between components with relatively small size differences B to D (e.g., between the frame 24 with the protrusion 24a and the bracket 11 with the recess 11a). Within this limited movement range, no physical interference occurs between the frame 24 and the rotating plate 21, where a relatively large size difference A exists. Therefore, damage to the rotating plate 21 due to contact with the frame 24 during the assembly of the encoder 20 can be suppressed.

[0067] The following uses Figure 7 This indicates the location of the light source 22s and the light-receiving element 22r configured in the optical module 22. Figure 7 This is a top view of the optical module 22 as viewed from the rotating plate 21 in the motor 10 according to this embodiment.

[0068] The optical module 22 is divided into a first region 22a and a second region 22b by a first line segment L1. A plurality of light-receiving elements 22r are arranged in the first region 22a, and a light source 22s is arranged in the second region 22b. Each of the multiple light-receiving elements 22r has a rectangular shape and is arranged parallel to the long side of the rectangle. As a result, since the optical module 22 is configured such that at least a portion of it overlaps with the first line segment L1 when viewed from the axial direction, tilting of the optical module 22 can be suppressed, thereby maintaining it stably.

[0069] In addition, Figure 7 In this configuration, multiple light-receiving elements 22r are arranged such that their long sides are parallel to the first line segment L1, but this configuration is not limited to that; for example, the long sides of the multiple light-receiving elements 22r can also be arranged perpendicular to the first line segment. Furthermore, in... Figure 7 In the example, the optical module 22 has three light-receiving elements 22r, but it is not limited to three; it may also have two or four or more light-receiving elements. The optical module 22 has multiple light-receiving elements 22r to accurately determine the rotational position and speed of the shaft 12 by illuminating multiple light-receiving elements 22r with light from the light source 22s. Furthermore, the multiple light-receiving elements 22r may have the same shape, but they may also have different shapes, or two may have the same shape while the remaining ones have other shapes. Additionally, if only the light intensity of the light source 22s is obtained, the light-receiving element 22r may also be a single element.

[0070] <Example 1 of other optical module configurations>

[0071] exist Figure 8Another configuration example 1 of the optical module 22 is shown. Figure 8 This is a top view showing the configuration of the light source 22s and light-receiving elements 22r in another configuration example 1 of the optical module 22 of the motor 10 according to this embodiment. The optical module 22 is an example in which the light source 22s is configured in a first region 22a and multiple light-receiving elements 22r are configured in a second region 22b. As a result, since the optical module 22 is configured such that at least a portion of it overlaps with the first line segment L1 when viewed from the axial direction, tilting of the optical module 22 can be suppressed, thereby maintaining it stably.

[0072] <Example 2 of other optical module configurations>

[0073] exist Figure 9 Another configuration example 2 of the optical module 22 is shown. Figure 9 This is a top view illustrating the configuration of the light source 22s and light-receiving elements 22r in another configuration example 2 of the optical module 22 of the motor 10 according to this embodiment. Another configuration example 2 of the optical module 22 is an example in which the light source 22s and a plurality of light-receiving elements 22r are arranged on the first line segment L1. As a result, since the optical module 22 is configured such that at least a portion of it overlaps with the first line segment L1 when viewed from the axial direction, tilting of the optical module 22 can be suppressed, thereby maintaining it stably.

[0074] <Example 3 of other optical module configurations>

[0075] exist Figure 10 Another configuration example 3 of the optical module 22 is shown. Figure 10 This is a top view illustrating the configuration of the light source 22s and multiple light-receiving elements 22r in another configuration example 3 of the optical module 22 of the motor 10 according to this embodiment. Another configuration example 3 of the optical module 22 is an example of arranging the light source 22s and the light-receiving elements 22r on the first line segment L1. As a result, since the optical module 22 is configured such that at least a portion of it overlaps with the first line segment L1 when viewed from the axial direction, tilting of the optical module 22 can be suppressed, thereby maintaining it stably.

[0076] <Variation Example 1>

[0077] The following describes a variation of the configuration of the optical module 22 and its surrounding components in this embodiment. More specifically, an example is described where the light-receiving element 22r receives light Lb emitted from the light source 22s and transmitted through the rotating plate 21.

[0078] Figure 11This is a cross-sectional view schematically illustrating the arrangement of the optical module 22, substrate 23, and rotating plate 21 in a modified example 1 of the motor 10 according to this embodiment. In the modified example 1, the light source 22s is fixed to the optical module 22, and the light-receiving element 22r is fixed to the bracket 11. Light Lb emitted from the light source 22s is transmitted through a pattern 21p provided on the rotating plate 21 and incident on the light-receiving element 22r. The light-receiving element 22r reads the pattern obtained by the light Lb passing through the pattern 21p, thereby reading the rotational speed and rotation angle of the rotating plate 21.

[0079] <Variation Example 2>

[0080] Figure 12 This is a cross-sectional view schematically illustrating the arrangement of the optical module 22, substrate 23, and rotating plate 21 in a modified example 2 of the motor 10 according to this embodiment. In modified example 2, a light-receiving element 22r is fixed to the optical module 22, and a light source 22s is fixed to the bracket 11. Light Lb emitted from the light source 22s is transmitted through a pattern 21p provided on the rotating plate 21 and incident on the light-receiving element 22r. The light-receiving element 22r reads the pattern obtained by the light Lb passing through the pattern 21p, thereby reading the rotational speed and rotation angle of the rotating plate 21.

[0081] Implementation Method 2

[0082] This invention describes Embodiment 2. The arrangement of the optical module 22, etc., on the substrate 23 in this embodiment differs from that in Embodiment 1 described above. Other structural aspects are the same as in Embodiment 1. Hereinafter, the differences from Embodiment 1 will be primarily described.

[0083] Figure 4 This is a schematic diagram of the base plate 23 in the motor 10 according to this embodiment, as viewed from the rotating plate 21. Figure 4 As shown, viewed from the axial direction, the optical module 22 is positioned on the first line segment L1, but not at a position overlapping with the midpoint M of the first line segment L1. Furthermore, in the optical module 22, the ratio of the area of ​​the first region 22a to the area of ​​the second region 22b is 1:2. Thus, even though the optical module 22 is not positioned overlapping with the midpoint M of the first line segment L1 when viewed from the axial direction, and even though the center point of the optical module 22 is not located on the first line segment L1, the effects of this disclosure are still achieved.

[0084] Furthermore, the first mounting holes 23a to the third mounting holes 23c are positioned in a rotationally symmetrical manner about the rotation axis of the rotating plate 21. More specifically, the first mounting holes 23a to the third mounting holes 23c are arranged concentrically around the axis of the shaft 12 and are equally spaced (at 120° intervals) around the circumference of the substrate 23. Therefore, in this embodiment, the first line segment L1, the second line segment L2, and the third line segment L3 form an equilateral triangle.

[0085] Industrial availability

[0086] This disclosure can be used in encoders and motors incorporating them.

[0087] Explanation of reference numerals in the attached figures

[0088] 10: Electric motor

[0089] 11: Bracket

[0090] 11a: concave part

[0091] 12: Shaft

[0092] 13: Bearings

[0093] 14: Screws

[0094] 15: Rotor

[0095] 16: Stator

[0096] 17: Shell

[0097] 20: Encoder

[0098] 21: Rotating plate

[0099] 22: Optical Module

[0100] 22a: Region 1

[0101] 22b: Region 2

[0102] 22r: Light receiving element

[0103] 22s: Light source

[0104] 23: Substrate

[0105] 23a: First mounting hole

[0106] 23b: Second mounting hole

[0107] 23c: 3rd mounting hole

[0108] 24: Framework

[0109] 24a: convex part

[0110] 24b: Through hole

[0111] 25: Protrusion

[0112] 25a: Bolt hole

[0113] 26: Bolt

[0114] D1: Inner Dimensions

[0115] D2: External dimensions

[0116] D3: Inner Dimensions

[0117] D4: External Dimensions

[0118] D5: External dimensions

[0119] D6: Inner Dimensions

[0120] D7: Inner Dimensions

[0121] L1: Line segment 1

[0122] L2: Segment 2

[0123] L3: Line segment 3

[0124] M: Midpoint.

Claims

1. An encoder, comprising: A rotating plate is mounted on a shaft and rotates around the rotating shaft. Bracket, supporting the shaft; An optical module includes at least one of a light source for irradiating light onto the rotating plate and a light-receiving element for receiving light reflected from or transmitted through the rotating plate. A substrate, on which the optical module is configured; and The frame supports the substrate. The substrate has a first mounting hole and a second mounting hole, and is screwed to the frame by a first screw inserted in the first mounting hole and a second screw inserted in the second mounting hole. Viewed along the axis of rotation, the optical module is positioned on a first line segment connecting the center of the first mounting hole and the center of the second mounting hole. The bracket has a plurality of recesses in the axial direction on the surface opposite to the frame. The frame has a plurality of protrusions that protrude in the axial direction at positions corresponding to the recesses of the bracket, which are spaced apart and enter the recesses.

2. The encoder according to claim 1, wherein, Viewed along the axis of rotation, the optical module is generally rectangular and is divided into a first region and a second region by the first line segment. The ratio of the area of ​​the first region to the area of ​​the second region is 1:1 to 1:

2.

3. The encoder according to claim 2, wherein, The ratio of the area of ​​the first region to the area of ​​the second region is 1:

1.

4. The encoder according to any one of claims 1 to 3, wherein, Viewed from the direction along the rotation axis, the optical module is positioned at a point overlapping the midpoint of the first line segment.

5. The encoder according to any one of claims 1 to 3, wherein, The substrate also has a third mounting hole. The first mounting hole, the second mounting hole, and the third mounting hole are configured in a position that is asymmetrical about the rotation axis.

6. The encoder according to claim 5, wherein, When the substrate is viewed along the axis of rotation, the first line segment, the second line segment connecting the center of the first mounting hole and the center of the third mounting hole, and the third line segment connecting the center of the second mounting hole and the center of the third mounting hole form an isosceles triangle with a base angle larger than the apex angle and the first line segment as the base.

7. The encoder according to claim 5, wherein, The frame also has three through holes located at positions corresponding to the first to third mounting holes and through which the screws are inserted. In the radial direction of the rotating plate, the difference between the inner dimension of the frame and the outer dimension of the rotating plate is greater than the difference between the inner dimension of the three through holes and the outer dimension of the screw shaft.

8. The encoder according to any one of claims 1 to 3, wherein, In the radial direction of the rotating plate, the difference between the inner dimension of the frame and the outer dimension of the rotating plate is greater than the difference between the inner dimensions of the first mounting hole and the second mounting hole and the outer dimension of the shaft portion of the screw.

9. The encoder according to claim 1, wherein, The plurality of recesses are arranged at equal intervals in the circumferential direction of the motor.

10. An electric motor, comprising: The encoder according to any one of claims 1 to 9; The bracket; and The shaft passes through the bracket. The shaft is mounted to the rotating plate and rotates together with the rotating plate. The substrate and the frame are together secured to the bracket using the screws.

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