Encoder and motor provided with it

Abstract

Inhibiting damage of a rotating plate. An encoder (20) includes a support (11), a rotating plate (21) rotating around a rotating shaft, an optical module (22) opposing the rotating plate (21) and having at least one of a light source and a light receiving element, a substrate (23) on which the optical module (22) is mounted, and a frame (24) fixed to the support (11) and supporting the substrate (23). The support (11) has three or more recesses (11a) on a surface opposing the frame (24). The frame (24) has three or more protrusions (24a) entering the recesses (11a) of the support (11) through a gap. In a radial direction of the rotating plate (21), a difference between an inner dimension (D1) of the frame (24) and an outer dimension (D2) of the rotating plate (21) is larger than a difference between an inner dimension (D3) of the recess (11a) and an outer dimension (D4) of the protrusion (24a).

Description

Technical Field

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

[0002] Conventionally, encoders for detecting the rotational position of a motor shaft are known (e.g., Patent Document 1). The encoder disclosed in Patent Document 1 includes a rotating plate mounted on the shaft and provided with a given pattern, and a main body provided with a detector for detecting the given pattern. When viewed from the axial direction of the shaft, the main body is fixed to a given object in a fixed position arranged in a line-symmetrical manner with respect to an imaginary straight line connecting the detection unit and the center of the shaft.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-211347 Summary of the Invention

[0006] However, when fixing the main body to the object, fine adjustments to the fixing position of the main body are required to adjust the relative position of the detector with respect to the rotating plate. During such fine adjustments, there is a concern that the rotating plate may deform or be damaged due to contact between the main body and the rotating plate. Under these circumstances, one of the objectives of this disclosure is to suppress damage to the rotating plate.

[0007] The first aspect of this disclosure relates to an encoder. The encoder comprises: a bracket; a rotating plate that rotates about a rotation axis; an optical module opposite the rotating plate, including at least one of a light source and a light-receiving element, the light source irradiating the rotating plate, and the light-receiving element receiving light irradiated from the light source and reflected by the rotating plate or transmitted through the rotating plate; a substrate on which the optical module is mounted; and a frame fixed to the bracket and supporting the substrate. The bracket has three or more recesses on the surface opposite the frame, and the frame has three or more protrusions at positions corresponding to the three or more recesses, each with a gap extending into the recesses of the bracket. In the radial direction of the rotating plate, the difference between the internal dimension of the frame and the external dimension of the rotating plate is greater than the difference between the internal dimension of the recesses and the external dimension of the protrusions.

[0008] Another second aspect of this disclosure relates to a motor. This motor includes the aforementioned encoder, a shaft extending through the bracket, a rotor mounted on the shaft, a stator opposite the rotor, and a housing coupled to the bracket and accommodating the rotor and the stator. The rotating plate is mounted on the shaft and rotates together with the shaft.

[0009] This disclosure relates to a third aspect of an encoder. The encoder comprises: a rotating plate that rotates about a rotation axis; an optical module opposite the rotating plate, including at least one of a light source and a light-receiving element, the light source irradiating the rotating plate, and the light-receiving element receiving light irradiated from the light source and reflected by the rotating plate or transmitted through the rotating plate; a substrate on which the optical module is mounted; and a frame supporting the substrate. The substrate has a first mounting hole, a second mounting hole, and a third mounting hole through which screws are inserted, the screws fixing the substrate and the frame in a mutually positioned state. The frame 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 internal dimension of the frame and the external dimension of the rotating plate is greater than the difference between the internal dimensions of the first to third mounting holes and the external dimension of the screw's shaft portion, or the difference between the internal dimensions of the three through holes and the external dimension of the screw's shaft portion.

[0010] The fourth aspect of this disclosure relates to a motor. This motor includes a bracket, a shaft passing through the bracket, and an encoder from the aforementioned third aspect. The rotating plate is mounted on the shaft and rotates with it. The base plate, together with the frame, is fixed to the bracket by the screws.

[0011] According to this disclosure, damage to the rotating plate can be suppressed. Attached Figure Description

[0012] Figure 1 This is a schematic cross-sectional view of the encoder-equipped motor according to Embodiment 1.

[0013] Figure 2 This is a schematic diagram showing the substrate of the motor according to Embodiment 1 as viewed from the rotating plate.

[0014] Figure 3 This is a schematic diagram of the motor according to Embodiment 1, shown from the perspective of the housing frame.

[0015] Figure 4 This is a schematic diagram showing the substrate of the motor according to Embodiment 2 as viewed from the rotating plate.

[0016] 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.

[0017] Figure 6 This is a cross-sectional view schematically showing the arrangement of the optical module, substrate, and rotating plate of the motor according to Embodiment 1.

[0018] Figure 7This 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.

[0019] Figure 8 This is a schematic diagram showing the support of the motor according to Embodiment 1 as viewed from the substrate.

[0020] Figure 9 This diagram illustrates the arrangement of the inner peripheral surfaces of the support, the frame, and the outer peripheral surfaces of the boss when viewed from the substrate, with respect to the motor according to Embodiment 1.

[0021] Figure 10 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 implementations of the encoders and motors related to this disclosure. However, this disclosure is not limited to the examples described below. Specific values ​​and materials are sometimes illustrated in the following description, but other values ​​and materials may be applied as long as the effects of this disclosure are achieved.

[0023] (encoder)

[0024] An embodiment of the encoder disclosed herein (hereinafter also referred to as the first encoder) includes a bracket, a rotating plate, an optical module, a substrate, and a frame.

[0025] The bracket is a component used to mount the first encoder to the motor housing.

[0026] The rotating plate rotates around a rotating axis. The rotating plate can also be mounted on the motor shaft. The rotating plate can be mounted directly or indirectly relative to the shaft. In the latter case, for example, 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 number of rotations. Here, the rotational position of the shaft refers to its relative or absolute angular position, and the number of rotations refers to the number of times the shaft rotates.

[0027] 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 emitted from the light source and reflected by the rotating plate (reflected light), or light 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 positioned 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 positioned on one side of the rotating plate, and the other is positioned 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 number of revolutions of the shaft.

[0028] Optical modules are mounted on the substrate. Various electronic components can also be mounted on the substrate. The substrate can also be substantially circular. "Substantially circular" means, for example, a plate whose outer edge is more than 80% circular.

[0029] The frame houses the rotating plate and supports the substrate so that the optical module is positioned opposite the rotating plate. The frame and substrate can also be fixed together by a given fixing unit. The frame can also be substantially cylindrical. In other words, the frame can also 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.

[0030] Here, the support has three or more recesses on the surface opposite to the frame. These three or more recesses may also be recessed along the rotation axis of the rotating plate. The three or more recesses may also be arranged in a concentric circle. In the circumferential direction of the motor, the three or more recesses may be arranged at equal or unequal intervals. When viewed from the direction along the rotation axis of the rotating plate, the recesses may be, for example, circular, but are not limited to this.

[0031] The aforementioned frame has three or more protrusions at positions corresponding to the aforementioned three or more recesses, each interspersed with a gap and entering the recesses of the support. The number of protrusions may be the same as or less than the number of recesses. The three or more protrusions may also protrude in the direction along the rotation axis of the rotating plate. Each of the three or more protrusions is configured to enter a corresponding recess of the support. When viewed from the direction along the rotation axis of the rotating plate, the protrusions may be, for example, circular, but are not limited thereto.

[0032] Furthermore, 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 dimension (or inner diameter if the recess is circular) of the bracket and the outer dimension (or outer diameter if the protrusion is circular) of the frame (hereinafter also referred to as dimension difference B).

[0033] Here, during the assembly of the first encoder, etc., while fine-tuning the relative position of the optical module with respect to the rotating plate, the positions of the substrate and frame on which the optical module is mounted are also fine-tuned. During this fine-tuning, the protrusion of the frame enters the recess of the support, so that in the radial direction of the rotating plate, the frame (as well as the substrate and optical module) moves only within a range where the outer surface of the protrusion does not contact the inner surface of the recess. Furthermore, due to the aforementioned relationship between the size difference A and the size difference B (where size difference A is greater than size difference B), even if the frame moves to its maximum extent within this range, the inner surface of the frame does not contact the outer edge of the rotating plate. Therefore, during the assembly of the first encoder, etc., damage to the rotating plate due to contact with the frame can be suppressed.

[0034] The frame can also have three or more protrusions arranged in asymmetrical positions about the rotation axis of the rotating plate. According to this structure, the relative position between the frame and the support is determined in the circumferential direction of the rotating plate by the protrusions of the frame and the recesses of the support. This allows for the prevention of assembly errors in the first encoder. Furthermore, the three or more protrusions can also be arranged in rotationally symmetrical positions about the rotation axis of the rotating plate. For example, it is possible to arrange three protrusions at equal intervals (120° intervals) in the circumferential direction of the rotating plate.

[0035] Another embodiment of this disclosure relates to an encoder (hereinafter also referred to as a second encoder) comprising a rotating plate, an optical module, a substrate, and a frame. The structure of the rotating plate and the substrate of the second encoder may also be the same as those of the first encoder.

[0036] The substrate has a first mounting hole, a second mounting hole, and a third mounting hole for screws to be inserted. The screws secure the substrate and the frame in a mutually positioned state. The first to third mounting holes can also be configured in asymmetrical positions that rotate about the rotation axis of the rotating plate.

[0037] The frame has three through holes located at positions corresponding to the first to third mounting holes, each for the insertion of the aforementioned screws. When viewed along the rotation axis of the rotating plate, the centers of the three through holes may also overlap with the centers of the first to third mounting holes.

[0038] Furthermore, in the radial direction of the rotating plate, the difference between the internal dimension of the frame and the external dimension of the rotating plate (difference A) is greater than the difference between the internal dimensions of the first to third mounting holes and the external dimension of the screw shaft (hereinafter also referred to as difference C), or the difference between the internal dimensions of the three through holes and the external dimension of the screw shaft (hereinafter also referred to as difference D).

[0039] Here, during the assembly of the second encoder, etc., when making fine adjustments to the position of the optical module relative to the rotating plate, the positions of the substrate and frame on which the optical module is mounted are also finely adjusted. During this fine adjustment, the shaft of the screw is inserted into the corresponding mounting hole of the substrate and the corresponding through hole of the frame. Therefore, in the radial direction of the rotating plate, the substrate, frame (and optical module) can only move within a range where the shaft of the screw does not contact the inner edge of the mounting hole or the inner surface of the through hole. Furthermore, due to the aforementioned relationship between the size difference A and size difference C or size difference D (size difference A is greater than size difference C or size difference D), 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, during the assembly of the second encoder, etc., damage to the rotating plate due to contact with the frame can be suppressed.

[0040] (motor)

[0041] One embodiment of this disclosure relates to a motor (hereinafter also referred to as the first motor) comprising the first encoder, shaft, rotor, stator, and housing described above. The motor may be, for example, an internal rotor type three-phase synchronous motor, but is not limited thereto.

[0042] The shaft passes through the bracket of the first encoder. The rotating plate of the first encoder is mounted on the shaft and rotates together with the shaft.

[0043] The rotor is mounted on the shaft. The rotor may be constructed, for example, of laminated steel plates, but is not limited to this. The rotor may also have multiple permanent magnets. The rotor may also be, for example, a rotor with embedded magnets, but is not limited to this.

[0044] The stator is positioned opposite the rotor. The stator may also be positioned opposite the rotor through an air gap. The stator may be constructed, for example, of laminated steel plates, but is not limited to this. The stator may also have multiple teeth and coils wound around the teeth. The stator may also be, for example, a stator with concentrated winding, but is not limited to this.

[0045] The housing and support are combined to house the rotor and stator. The housing and support can be separate or integrally formed. The housing can also be made of non-magnetic material.

[0046] The support can also house the rotor and stator together with the housing.

[0047] Another embodiment of this disclosure relates to a motor (hereinafter also referred to as the second motor) comprising a bracket, a shaft, and the aforementioned second encoder. The motor may also be, for example, a three-phase synchronous motor with a built-in rotor, but is not limited thereto.

[0048] The bracket is the component for mounting the second encoder. The base plate of the second encoder is fixed to the bracket together with the frame by screws.

[0049] The shaft passes through the bracket. The rotating plate of the second encoder is mounted on the shaft and rotates together with the shaft.

[0050] As described above, according to this disclosure, damage to the rotating plate can be suppressed during encoder assembly, etc.

[0051] Hereinafter, an example of an encoder and motor according to the present disclosure will be specifically described with reference to the accompanying drawings. The aforementioned constituent elements can be applied to the constituent elements of the encoder and motor of the example described below. The constituent elements of the encoder and motor of the example described below can be modified based on the above description. Furthermore, the matters described below can also be applied to the above-described embodiments. In the constituent elements of the encoder and motor of the example described below, constituent elements that are not essential to the encoder and motor disclosed herein may be omitted. Additionally, the figures shown below are schematic and do not accurately reflect the actual shape, size, number, etc., of the components.

[0052] Implementation Method 1

[0053] Embodiment 1 of this disclosure will be described. The motor 10 in this embodiment is a three-phase synchronous motor with a built-in rotor, but it is not limited thereto.

[0054] 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. Additionally, in Figures 1-10 To clearly illustrate the configuration of each component, an orthogonal xyz coordinate system is indicated. This xyz orthogonal coordinate system designates the direction from the substrate 23 toward the shaft 12 as positive, and sets the z-axis parallel to the axis of the shaft 12. Furthermore, the surface parallel to the main surface of the substrate 23 is designated as the xy plane. Figure 2 The direction of the third mounting hole 23c of the substrate 23 toward the midpoint M is set as positive, and the x-axis is set parallel to the straight line passing through the midpoint M from the third mounting hole 23c. Furthermore, from... Figure 2 The direction from the first mounting hole 23a to the second mounting hole 23b on the substrate 23 shown is set as positive, and the y-axis is set parallel to the line connecting the first mounting hole 23a and the second mounting hole 23b. Furthermore, Figure 1 This is a cross-sectional view of motor 10 after being cut by a plane that passes through the axis of shaft 12 and is parallel to the xz plane.

[0055] The shaft 12 passes through the bracket 11 and is rotatably supported on the bracket 11 via the bearing 13. The rotating plate 21 of the encoder 20 (described later) is mounted on the shaft 12 and rotates together with the shaft 12.

[0056] The rotor 15 is mounted on the shaft 12. The rotor 15 rotates together with the shaft 12. The rotor 15 in this embodiment is a rotor with an embedded magnet, but it is not limited to this.

[0057] The stator 16 is positioned opposite the rotor 15 across an air gap. The stator 16 is disposed radially on the outside of the rotor 15 of the motor 10. The stator 16 in this embodiment is a stator with a concentrated winding method, but it is not limited to this.

[0058] The interior of the housing 17 is a hollow cylindrical component. The housing 17 is combined with the support 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 is made of a non-magnetic material (e.g., aluminum or aluminum alloy). In this embodiment, the housing 17 and the support 11 are separate from each other, but they can also be integrally formed.

[0059] 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 a permanent magnet and a power generation element. Figure 2 This is a schematic diagram of the substrate 23 in the motor 10 according to Embodiment 1, as viewed from the rotating plate 21. Figure 3 This is a schematic diagram showing the frame 24 of the motor 10 according to Embodiment 1, viewed from the housing 17. Figures 1-3 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, but in this case, the bracket 11 is also a component of the motor 10.

[0060] 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 is fixed to the inner surface of the through hole to support the shaft 12 so that it can rotate. The bracket 11 and the housing 17 together house the rotor 15 and the stator 16.

[0061] The rotating plate 21 is mounted to the shaft 12 of the motor 10 via a boss 25. The outer contour 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.

[0062] 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 1 as well as Figure 5As shown, the rotating plate 21 rotates together with the shaft 12 about the axis of rotation of the shaft 12. The rotating plate 21 has a given pattern 21p formed along its circumference. The given pattern is used to detect the rotational position and number of rotations of the shaft 12. The given pattern 21p is, for example, a structure in which reflective and non-reflective areas are arranged adjacent to each other in the circumferential direction. Alternatively, in the given pattern 21p, the reflective areas may also be formed by a pattern such as a barcode or QR code (registered trademark, hereinafter the same).

[0063] Figure 6 This is a cross-sectional view schematically showing the arrangement of the optical module 22, the substrate 23, and the rotating plate 21 of the motor 10 according to this embodiment. Figure 7 This is a top view showing the configuration of the light source 22s and the light-receiving element 22r of the optical module 22. (See attached image.) Figure 6 As shown, the optical module 22 includes a light source 22s (e.g., an LED (light-emitting diode)) that illuminates 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. From the direction along the rotation axis of the rotating plate 21 ( Figure 1 When observing in the vertical direction (hereinafter also referred to as the axial direction), the optical module 22 is as follows: Figure 7 The shape shown 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 that has been irradiated by the light source and reflected by the rotating plate 21. The light-receiving element 22r can also be configured to receive light that has been irradiated by the light source 22s and transmitted through the rotating plate 21. In the case where 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 number of revolutions of the shaft 12.

[0064] In addition, Figure 6 In the example shown, the optical module 22 has both a light source 22s and a light-receiving element 22r, but the optical module 22 can 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.

[0065] An optical module 22 is mounted on the substrate 23. In addition, various electronic components 27 are mounted on the substrate 23.

[0066] 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 essentially a circular plate, having a first mounting hole 23a, a second mounting hole 23b, and a third mounting hole 23c. In the first mounting hole 23a to the third mounting hole 23c, as in... Figure 1 As shown in the portion with the third mounting hole 23c, screws 14 (or bolts) for mounting the substrate 23 and frame 24 together to the bracket 11 are inserted. The screws 14 fix the substrate 23 and frame 24 in a mutually positioned state. That is, the relative positional relationship between the screws 14 and the bracket 11 is fixed. The first mounting holes 23a to the third mounting holes 23c are substantially circular and penetrate the substrate 23 in their thickness direction. "Substantially circular" means, for example, a shape in which more than 80% of the outer edge is composed of arcs.

[0067] When viewed axially, the optical module 22 is positioned to overlap with the midpoint M of the first line segment L1 connecting the center of the first mounting hole 23a and the center of 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, when viewed axially, 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. However, it is sufficient that the optical module 22 is configured such that at least a portion of it overlaps with the first line segment L1 when viewed axially. With such a configuration, tilting of the optical module 22 can be suppressed, and it can be held stably. 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.

[0068] 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 greater than the apex angle and the first line segment L1 as its base. Thus, the first mounting holes 23a to the third mounting holes 23c are positioned in a position that is asymmetrical about the rotation axis of the rotating plate 21.

[0069] Frame 24 is fixed to support 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 to frame 24 by a given fixing unit. Specifically, substrate 23 is fixed to frame 24 by screws 14.

[0070] Alternatively, when fixing the substrate 23 to the frame 24, the two can be fixed to each other, for example, by pressing the pins of the frame 24 into the pin holes formed in the substrate 23.

[0071] Figure 3 This is a schematic diagram of the motor 10 according to this embodiment, viewed from the housing 17 as a frame 24. Figure 8 This is a schematic diagram of the motor 10 according to this embodiment, viewed from the substrate 23 as the support 11. Figure 9 This diagram shows the arrangement of the bracket 11, the inner peripheral surface of the frame 24, and the outer peripheral surface of the boss 25, when viewed from the substrate 23 with respect to the motor 10 according to this embodiment. Furthermore, in Figure 9 In the diagram, dashed lines indicate the positions corresponding to the protrusion 24a of the frame 24 and the inner peripheral surface of the frame 24, while single-dotted lines indicate the positions corresponding to the outer peripheral surface of the boss 25.

[0072] like Figure 3 As shown, the frame 24 has three through holes 24b for the aforementioned screws 14 to be inserted. The three through holes 24b are positioned corresponding to the first mounting holes 23a to the third mounting holes 23c on the substrate 23, respectively. The internal dimension (inner diameter) D7 of each through hole 24b is shown in the figure. Figure 1 The internal dimensions (inner diameter) D6 of the first mounting holes 23a to the third mounting holes 23c on the substrate 23 (refer to) Figure 1 They are essentially equal, but can also be different. Each through hole 24b extends the frame 24 along its thickness direction ( Figure 1 The vertical direction (i.e., the z-axis direction) runs through the entire structure. The frame 24 and the base plate 23 are fixed to the bracket 11 by screws 14.

[0073] like Figure 8 As shown, the bracket 11 is on the surface opposite to the frame 24 ( Figure 1 The upper surface of the motor 10 has three recesses 11a. The three recesses 11a are recessed along the z-axis. The three recesses 11a are arranged at equal intervals (120° apart) in the circumferential direction of the motor 10. Each recess 11a is substantially circular. However, the shape of each recess 11a can also be any shape such as ellipse, rectangle, or polygon.

[0074] like Figure 3 as well as Figure 8 As shown, the frame 24 has three protrusions 24a at positions corresponding to the three recesses 11a, respectively, which enter the three recesses 11a of the support 11 through gaps (the radial gaps of the rotating plate 21). The three protrusions 24a protrude along the z-axis. The three protrusions 24a are arranged at equal intervals (120° apart) in the circumferential direction of the frame 24. Each protrusion 24a is substantially circular. However, the shape of each protrusion 24a can also be elliptical, rectangular, polygonal, or any other arbitrary shape.

[0075] like Figure 1 as well as Figure 9As shown, in the radial direction of the rotating plate 21 (e.g., in...) Figure 1 In the left-right direction (x-axis direction), hereinafter referred to as radial, the difference between the inner diameter (D1) of the frame 24 and the outer diameter (D2) of the rotating plate 21 (dimension difference A) is greater than the difference between the inner diameter (D3) of the recess 11a of the support 11 and the outer diameter (D4) of the protrusion 24a of the frame 24 (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 diameter D1 of the frame 24 is greater than the outer diameter D2 of the rotating plate 21 (D1 > D2), and the inner diameter D3 of the recess 11a is greater than the outer diameter D4 of the protrusion 24a (D3 > D4). Thus, in the radial direction, the protrusion 24a of the frame 24 and the inner circumferential surface of the frame 24 are always located further outward than the outer circumferential surface of the boss 25.

[0076] In addition, such as Figure 1 As shown, in the radial direction, the dimensional difference A is greater than the difference (dimensional difference C) between the inner dimension (inner diameter) D6 of the first mounting hole 23a of the substrate 23 and the outer dimension (outer diameter) 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 is greater than the outer dimension D5 of the shaft portion of the screw 14 (D6 > D5).

[0077] Furthermore, in the radial direction, the dimensional difference A is greater than the difference (dimensional difference D) between the internal dimension (inner diameter) D7 of the through hole 24b of the frame 24 and the external dimension D5 of the shaft portion of the screw 14. The dimensional difference D corresponds to the maximum 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 internal dimension D7 of the through hole 24b is greater than the external dimension D5 of the shaft portion of the screw 14 (D7 > D5).

[0078] By utilizing the aforementioned relationship between the size differences A and B to D, 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, fine-tuning is also performed on the positions of the substrate 23 and frame 24 on which the optical module 22 is mounted. During this fine-tuning, physical interference between components with relatively small size differences B to D (e.g., between the frame 24 with the protrusion 24a and the support 11 with the recess 11a) is limited, thereby restricting the radial movement range of the rotating plate 21 relative to the frame 24 and substrate 23. 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, the protrusion 24a of the frame 24 and the inner peripheral surface of the frame 24 are always positioned further outward than the outer peripheral surface of the boss 25. Therefore, during the assembly of the encoder 20, damage to the rotating plate 21 due to contact between the frame 24 and the boss 25 can be suppressed.

[0079] Regarding the location of the light source 22s and the light-receiving element 22r configured in the optical module 22, the following uses... Figure 7 Please provide an explanation. 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.

[0080] 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. Thus, when viewed from the axial direction, the optical module 22 is configured such that at least a portion overlaps with the first line segment L1, thereby suppressing tilting of the optical module 22 when it is screwed in, and thus stably holding it in place.

[0081] In addition, Figure 7 In this configuration, multiple light-receiving elements 22r are arranged such that their long sides are perpendicular to the first line segment L1, but this configuration is not limited to this. For example, the long sides of the multiple light-receiving elements 22r can also be arranged parallel to the first line segment. Furthermore, in... Figure 7 In the example, the optical module 22 has three light-receiving elements 22r, but 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 number of revolutions of the shaft 12 by illuminating the light from the light source 22s across multiple light-receiving elements 22r. 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 others have different shapes. Additionally, if only the light intensity of the light source 22s is obtained, the number of light-receiving elements 22r may be odd.

[0082] In addition, it can also be with Figure 7 Conversely, a light source 22s is arranged in the first region 22a, and multiple light-receiving elements 22r are arranged in the second region 22b. Alternatively, one of the light source 22s and multiple light-receiving elements 22r may be configured to overlap with the first line segment L1.

[0083] <Variation Example>

[0084] Figure 10 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 of the motor 10 according to this embodiment. In this modified example, the light-receiving element 22r is fixed to the optical module 22, and the light source 22s is fixed to the bracket 11. Light Lb emitted from the light source 22s is transmitted through a pattern 21p disposed 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 enabling the reading of the number of revolutions and rotation angle of the rotating plate 21. In this case, the given pattern 21p is, for example, a structure in which the transmissive and non-transmissive regions are arranged adjacently in the circumferential direction. Furthermore, the transmissive region is formed, for example, by a through-hole disposed on the rotating plate 21. Regarding the given pattern 21p, the transmissive region may also be formed by a pattern such as a barcode or QR code.

[0085] Alternatively, in the above-described modified example, instead of fixing the light-receiving element 22r to the optical module 22 and the light source 22s to the bracket 11, the light source 22s can be fixed to the optical module 22 and the light-receiving element 22r can be fixed to the bracket 11.

[0086] Implementation Method 2

[0087] Embodiment 2 of this disclosure will be described. In this embodiment, the arrangement of the optical module 22, etc., on the substrate 23 differs from that in Embodiment 1. Other structures are the same as in Embodiment 1. Hereinafter, the differences from Embodiment 1 will be mainly described.

[0088] 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, when viewed axially, the optical module 22 is disposed on the first line segment L1, at a position that does not overlap 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, when viewed axially, even if the optical module 22 is not disposed at a position overlapping with the midpoint M of the first line segment L1, and even if the center point of the optical module 22 is not located on the first line segment L1, the effects of this disclosure can still be achieved.

[0089] Furthermore, the first mounting holes 23a to the third mounting holes 23c are positioned rotationally symmetrical about the rotation axis of the rotating plate 21. More specifically, the first mounting holes 23a to the third mounting holes 23c are arranged in a concentric circle with the axis of the shaft 12 as the center, 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.

[0090] Industrial availability

[0091] This disclosure can be used in encoders and motors having the same.

[0092] Symbol Explanation

[0093] 10: Motor

[0094] 11: Bracket

[0095] 11a: concave part

[0096] 12: Shaft

[0097] 13: Bearings

[0098] 14: Screws

[0099] 15: Rotor

[0100] 16: Stator

[0101] 17: Shell

[0102] 20: Encoder

[0103] 21: Rotating plate

[0104] 22: Optical Module

[0105] 22a: Region 1

[0106] 22b: Region 2

[0107] 23: Substrate

[0108] 23a: First mounting hole

[0109] 23b: Second mounting hole

[0110] 23c: 3rd mounting hole

[0111] 24: Framework

[0112] 24a: convex part

[0113] 24b: Through hole

[0114] 25: Protrusion

[0115] 25a: Bolt hole

[0116] 26: Bolt

[0117] D1: Internal dimensions

[0118] D2: External Dimensions

[0119] D3: Internal Dimensions

[0120] D4: External Dimensions

[0121] D5: External Dimensions

[0122] D6: Internal Dimensions

[0123] D7: Internal Dimensions

[0124] L1: Line segment 1

[0125] L2: Segment 2

[0126] L3: Line segment 3

[0127] M: Midpoint.

Claims

1. An encoder, comprising: support; The rotating plate rotates around the rotating axis. An optical module, opposite to the rotating plate, includes a light source that illuminates the rotating plate and a light-receiving element that receives the light reflected by the rotating plate, or includes one of a light source that illuminates the rotating plate and a light-receiving element that receives the light transmitted through the rotating plate. A substrate, on which the optical module is configured; and The frame is fixed to the bracket and supports the substrate. The bracket has more than three recesses on the surface opposite to the frame. The frame has three or more protrusions at positions corresponding to the three or more recesses, each protruding through a gap and entering the recess of the support. In the radial direction of the rotating plate, the difference between the internal dimension of the frame and the external dimension of the rotating plate is greater than the difference between the internal dimension of the recess and the external dimension of the protrusion.

2. The encoder according to claim 1, wherein, Three or more of the protrusions are arranged in a position that is asymmetrical about the axis of rotation.

3. The encoder according to claim 1, wherein, The substrate has a first mounting hole, a second mounting hole, and a third mounting hole for screws to be inserted. The screws fix the substrate and the frame in a mutually positioned state. The frame has three through holes located at positions corresponding to the first to third mounting holes, respectively, for the screws to be inserted. In the radial direction of the rotating plate, the difference between the internal dimension of the frame and the external dimension of the rotating plate is greater than the difference between the internal dimensions of the first to third mounting holes and the external dimension of the screw shaft, or the difference between the internal dimensions of the three through holes and the external dimension of the screw shaft.

4. A motor, comprising: The encoder as described in claim 1 or 2; A shaft, penetrating the bracket; The rotor is mounted on the shaft. The stator is opposite the rotor; and The housing, combined with the bracket, accommodates the rotor and the stator. The rotating plate is mounted on the shaft and rotates together with the shaft.

5. The motor according to claim 4, wherein, The bracket, together with the housing, accommodates the rotor and the stator.

6. A motor, comprising: support; The shaft penetrating the bracket; and The encoder according to claim 3, The rotating plate is mounted on the shaft and rotates together with the shaft. The substrate and the frame are fixed to the bracket together by the screws.

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