WO2019239488A1

WO2019239488A1 - Encoder and servomotor

Info

Publication number: WO2019239488A1
Application number: PCT/JP2018/022433
Authority: WO
Inventors: 雅史大熊; 大輔金森; 政範二村; 佐土根　俊和; 琢也野口
Original assignee: 三菱電機株式会社
Priority date: 2018-06-12
Filing date: 2018-06-12
Publication date: 2019-12-19
Also published as: JP6494896B1; TWI701424B; JPWO2019239488A1; TW202001193A; CN112262296A

Abstract

This encoder comprises a substrate-fixing part (3) and protrusions (3c) extending in the axial direction from an edge (31) of the substrate-fixing part (3). The encoder comprises: a substrate (1) that has recesses (1d) which are depressed in from the substrate periphery (1c) toward the inner side in the radial direction of the substrate-fixing part (3) and into which the protrusions (3c) fit; and an adhesive (11) that is provided in the gaps formed between the protrusions (3c) and the recesses (1d). The wall surface (10) constituting each recess (1d) is characterized by comprising: a first positioning surface (1d1) that determines the circumferential-direction position of the substrate (1) by abutting either a first end surface (3c1) of the protrusion (3c) in the circumferential direction of the substrate-fixing part (3) or a second end surface (3c2) on the opposite side from the first end surface (3c1); and a second positioning surface (1d2) that determines the radial-direction position of the substrate (1) by abutting the inner surface (3c3) of the protrusion (3c) in the radial direction.

Description

Encoder and servo motor

The present invention relates to an encoder and a servo motor that detect the rotational position of a rotor.

Patent Document 1 discloses a technique for fixing an encoder board to a housing using an adhesive. In the encoder substrate disclosed in Patent Document 1, a plurality of through holes for filling the adhesive are arranged in an annular shape apart from each other, and a position corresponding to these through holes is provided in a housing in which the encoder substrate is installed. A plurality of holes are formed. In addition, a plurality of positioning protrusions are arranged apart from each other in the housing in order to align a substrate provided in the housing. In the encoder configured as described above, when the encoder board is installed in the housing such that the through hole and the hole communicate with each other in the axial direction, the encoder board is held by a plurality of positioning protrusions. And after an encoder board | substrate is installed in a housing, an encoder board | substrate is fixed to a housing by filling an adhesive agent with a through-hole and a hole.

JP 2008-309675 A

However, in the encoder disclosed in Patent Document 1, it is necessary to provide a plurality of holes in the housing for adhesion of the encoder substrate to the housing, and further, in order to compensate for the lost substrate surface by providing the through-holes. It is necessary to enlarge the substrate. Therefore, there is a limit to reducing the diameter of the housing and the substrate in order to reduce the size of the encoder, and there has been a problem that the encoder cannot be further reduced in size.

The present invention has been made in view of the above, and an object of the present invention is to obtain an encoder that can be miniaturized even when a substrate in a positioned state is fixed to a housing.

In order to solve the above-described problems and achieve the object, the encoder of the present invention is provided at a corner portion formed by a cylindrical substrate fixing portion, an axial end portion of the substrate fixing portion, and an outer peripheral portion of the substrate fixing portion. And a protrusion extending in the axial direction from the corner. The encoder has a substrate surface that is in contact with the end portion, and a substrate that is formed on the outer periphery of the substrate that surrounds the substrate surface, and that has a recess that is recessed from the outer periphery of the substrate toward the inside of the substrate fixing portion in the radial direction. And a fixing member provided in a gap formed between the protrusion and the depression. The wall surface forming the recess is in contact with either the first end surface of the protrusion in the circumferential direction of the substrate fixing portion or the second end surface opposite to the first end surface, and determines the position in the circumferential direction of the substrate. It comprises a positioning surface and a second positioning surface that determines the radial position of the substrate in contact with the inner surface of the projection in the radial direction.

The encoder according to the present invention is advantageous in that it can be miniaturized even when the substrate in a positioned state is fixed to the housing.

The perspective view of the encoder which concerns on Embodiment 1 of this invention Enlarged view of the recess and protrusion shown in FIG. The figure which shows the board | substrate provided in the encoder which concerns on the 1st modification of Embodiment 1. FIG. IV-IV arrow sectional view shown in FIG. The figure which shows the board | substrate provided in the encoder which concerns on the 2nd modification of Embodiment 1. FIG. The figure which shows the protrusion provided in the encoder which concerns on the 3rd modification of Embodiment 1. FIG. The figure which shows the protrusion provided in the encoder which concerns on the 4th modification of Embodiment 1. FIG. The figure which shows the modification of the fitting structure of the board | substrate and three protrusions which are shown in FIG. The figure which shows the modification of the protrusion shown in FIG. External view of servo motor according to Embodiment 2

Hereinafter, an encoder and a servo motor according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a perspective view of an encoder according to Embodiment 1 of the present invention. FIG. 2 is an enlarged view of the recess and protrusion shown in FIG. The encoder 100 according to the first embodiment includes a substrate 1 having a first substrate surface 1a and a second substrate surface 1b opposite to the first substrate surface 1a, and an electronic component 2 provided on the second substrate surface 1b. And a cylindrical substrate fixing portion 3 having an end portion 3a with which the first substrate surface 1a is in contact, and the substrate 1 being fixed to the end portion 3a. The encoder 100 also includes a bottomed cylindrical cover 5 having a bottom portion 5 a facing the electronic component 2 and a cylindrical portion 5 b that is rotatably fitted to the outer peripheral portion 3 b of the board fixing portion 3.

The first substrate surface 1 a is an end surface of the substrate 1 facing the substrate fixing portion 3. The second substrate surface 1 b is an end surface of the substrate 1 that faces the bottom 5 a of the cover 5. The cover 5 is a component for suppressing a decrease in insulation performance due to intrusion of dust, metal pieces, and the like into the encoder 100.

The axial direction in which the central axis AX that passes through the radial center of the substrate fixing portion 3 extends is equal to the direction indicated by reference numeral D1 in FIG. The circumferential direction of the board | substrate fixing | fixed part 3 is equal to the direction shown by the code | symbol D2 in FIG. The radial direction of the substrate fixing portion 3 is indicated by a symbol D3 in FIG.

The electronic component 2 may be, for example, a component that forms a signal generation circuit that generates a signal indicating the rotational position of the rotor, a signal output circuit that outputs the signal to an encoder lead wire (not shown), or the like. It may be a component constituting a power supply circuit that supplies power supplied from a provided servo amplifier to a position detection unit or the like. The electronic component 2 is, for example, an IC (Integrated Circuit), a resistor, a coil, or a capacitor. There may be one electronic component 2 or a plurality of electronic components 2. In FIG. 1 and FIG. 2, the electronic component 2 is simulated by a cylindrical structure in order to simplify the description.

The substrate fixing part 3 is detachably fixed to the bracket 8 using screws 7. The bracket 8 is a member that closes an axial end of a motor case (not shown). The substrate fixing portion 3 is manufactured separately from the bracket 8 using an insulating material and then attached to the bracket 8, but may be manufactured integrally with the bracket 8 using an insulating material. Examples of the insulating material include polybutylene terephthalate, polyphenylene sulfide, and a liquid crystal polymer. By manufacturing the substrate fixing part 3 by die casting using an insulating resin, the substrate fixing part 3 having a complicated shape can be manufactured at low cost.

Three protrusions 3 c are formed on the substrate fixing part 3. The protrusion 3 c is a protruding member that is provided at a corner portion 31 formed by the axial end portion 3 a of the substrate fixing portion 3 and the outer peripheral portion 3 b of the substrate fixing portion 3 and extends from the corner portion 31 in the axial direction. The end 3 a of the substrate fixing part 3 is an end opposite to the bracket 8 side of the substrate fixing part 3. The three protrusions 3c are arranged away from each other in the circumferential direction. The protrusion 3 c is fitted into a recess 1 d formed on the substrate 1. The recess 1d is formed in the substrate outer peripheral portion 1c surrounding the first substrate surface 1a and the second substrate surface 1b. The recess 1d is a recess that is recessed from the substrate outer peripheral portion 1c toward the radially inner side. Each of the plurality of depressions 1d is provided corresponding to each of the plurality of protrusions 3c. In FIG. 1, three depressions 1 d are provided in the substrate 1. In the case where there are three protrusions 3c, for example, the substrate 1 is stably fixed as compared with the case where there are two protrusions 3c, and therefore the width in the circumferential direction of the protrusions 3c can be shortened. Since the width of the recess 1d in the circumferential direction can be shortened by the reduction in the width of the protrusion 3c, the component mounting area of the substrate 1 can be increased.

2 shows a recess 1d and a protrusion 3c viewed from the axial direction in which the central axis AX extends. 2 shows a protrusion 3c as viewed from the substrate outer peripheral portion 1c side of the substrate 1. The wall surface 10 that forms the depression 1d includes a first positioning surface 1d1 and a second positioning surface 1d2.

The first positioning surface 1d1 is a positioning surface that determines the circumferential position of the substrate 1 by contacting the first end surface 3c1 of the protrusion 3c in the circumferential direction. When the first end surface 3c1 of the protrusion 3c is in contact with the first positioning surface 1d1, the movement of the substrate 1 in the circumferential direction is suppressed. In FIG. 2, the first end surface 3c1 of the protrusion 3c is in contact with the first positioning surface 1d1 of the recess 1d. However, the first end surface 3c1 and the second end surface 3c2 of the protrusion 3c are formed on the wall surface 10 forming the recess 1d. If either one is in contact, the movement of the substrate 1 in the circumferential direction can be suppressed. Therefore, the second end surface 3c2 of the protrusion 3c may be in contact with the end surface on the opposite side to the first positioning surface 1d1 in the circumferential direction of the wall surface 10 forming the recess 1d. The second end surface 3c2 is an end surface opposite to the first end surface 3c1 of the protrusion 3c.

The second positioning surface 1d2 is a positioning surface that determines the radial position of the substrate 1 by contacting the inner surface 3c3 of the projection 3c in the radial direction. When the inner surface 3c3 of the protrusion 3c is in contact with the second positioning surface 1d2, the movement of the substrate 1 in the radial direction is suppressed.

The adhesive 11 as a fixing member is provided in the gap a between the surface 10A facing the second end surface 3c2 of the projection 3c and the second end surface 3c2 of the projection 3c in the wall surface 10 forming the depression 1d. The gap a is a space formed between the wall surface 10 forming the depression 1d and the second end surface 3c2 of the protrusion 3c in order to provide the adhesive 11. By providing the adhesive 11 in the gap a, the substrate 1 is connected to the second end surface 3c2 of the protrusion 3c via the adhesive 11. Therefore, the substrate 1 in a positioned state is fixed to the substrate fixing unit 3.

In addition, according to the encoder 100 according to the first embodiment, the gap 11 for providing the adhesive 11 is formed in the fitting portion where the protrusion 3c and the substrate 1 are fitted, so the adhesive 11 is filled. Therefore, it is not necessary to provide a plurality of through holes for the substrate 1. Further, it is not necessary to provide a plurality of holes for filling the substrate fixing portion 3 with the adhesive 11. Therefore, compared with the case where a plurality of through holes are formed in the substrate 1, the component mounting area of the substrate 1 can be increased and the mounting area of the pattern wiring on the substrate 1 can be increased. In addition, since it is not necessary to provide a plurality of holes for filling the adhesive 11 in the substrate fixing portion 3, the diameter of the substrate fixing portion 3 can be reduced, and the entire encoder 100 can be reduced in size.

Note that by using a low-viscosity adhesive 11, it is possible to prevent the adhesive 11 from dripping onto the electronic component 2 of the substrate 1 when the adhesive 11 is filled. Moreover, in order to suppress dripping of the adhesive 11 to the electronic component 2, a UV (UltraViolet) curable adhesive may be used. The UV curable adhesive is an adhesive formed of a resin that is cured by ultraviolet irradiation.

The protrusion 3c may be configured such that the height H in the axial direction is equal to the thickness T in the axial direction of the substrate 1, or the height H in the axial direction is greater than the thickness T in the axial direction of the substrate 1. May be configured to be higher. The height H in the axial direction of the protrusion 3c is equal to the axial width from the end 3a of the substrate fixing portion 3 to the tip 3c4 of the protrusion 3c. The thickness T in the axial direction of the substrate 1 is equal to the axial width from the first substrate surface 1 a to the second substrate surface 1 b of the substrate 1. When the height H in the axial direction of the protrusion 3c is configured to be higher than the thickness T in the axial direction of the substrate 1, as shown in FIG. 2, the second end surface 3c2 of the protrusion 3c is included in the second end surface 3c2. It is desirable to apply the adhesive 11 also to the portion protruding from the second substrate surface 1b. By applying the adhesive 11 in this way, the area where the adhesive 11 is applied to the protrusion 3c is larger than when the height H in the axial direction of the protrusion 3c is equal to the thickness T in the axial direction of the substrate 1. To increase. Accordingly, the substrate 1 can be more firmly fixed to the substrate fixing portion 3.

Alternatively, an adhesive 11 may be provided between the end 3 a of the substrate fixing unit 3 and the substrate 1. By providing the adhesive 11 between the end portion 3 a of the substrate fixing portion 3 and the substrate 1, the substrate is compared with the case where the adhesive 11 is not provided between the end portion 3 a of the substrate fixing portion 3 and the substrate 1. The substrate 1 can be more firmly fixed to the fixing portion 3.

In the encoder 100 according to the first embodiment, three fitting structures between the protrusion 3c and the recess 1d of the substrate 1 shown in FIG. 2 are used, but the configuration example of the encoder 100 is not limited to this. For example, of the three fitting structures, the two fitting structures are connected in such a manner that the first end surface 3c1 of the projection 3c is in contact with one end in the circumferential direction of the recess 1d, and the second end surface 3c2 of the projection 3c You may replace with the fitting structure which touches an end. When configured in this manner, the component mounting area of the board 1 is increased and the mounting area of the pattern wiring on the board 1 is increased as compared with the case where three fitting structures shown in FIG. 2 are used. Can do.

FIG. 3 is a diagram showing a substrate provided in the encoder according to the first modification of the first embodiment. 4 is a cross-sectional view taken along arrow IV-IV shown in FIG. The substrate 1A shown in FIGS. 3 and 4 is provided with a recess 1dA instead of the recess 1d. The depression 1dA has a shape in which the width in the circumferential direction of the wall surface 10 forming the depression 1dA is gradually reduced toward the inner side in the radial direction. The first end surface 3c1 of the protrusion 3c is in contact with the first positioning surface 1d1 of the recess 1dA. A part of the inner surface 3c3 of the protrusion 3c is in contact with the second positioning surface 1d2 of the recess 1dA.

The adhesive 11 is provided in the gap a1 between the surface 10A and the second end surface 3c2, and further provided in the gap a2 between the surface 10B and the non-contact surface 3c3A. The surface 10A is a surface facing the second end surface 3c2 of the protrusion 3c in the wall surface 10 forming the depression 1dA. The non-contact surface 3c3A is a surface that is not in contact with the second positioning surface 1d2 of the recess 1dA in the inner surface 3c3 of the protrusion 3c. The surface 10B is a surface facing the non-contact surface 3c3A among the wall surfaces 10 forming the depression 1dA.

By using the substrate 1A shown in FIGS. 3 and 4, the area of the wall surface 10 forming the recess 1dA is larger than the area of the wall surface 10 forming the recess 1d shown in FIG. The coating area increases, and the adhesive 11 becomes difficult to peel off from the substrate 1A. In addition, since the adhesive 11 is in contact with a part of the inner side surface 3c3 of the protrusion 3c, the adhesive 11 is hardly peeled off from the protrusion 3c. Therefore, the substrate 1A can be more firmly fixed to the substrate fixing portion 3.

FIG. 5 is a diagram showing a substrate provided in the encoder according to the second modification of the first embodiment. A recess 1 dB is formed in the substrate 1 </ b> B shown in FIG. 5. The recess 1 dB has a shape in which the width in the circumferential direction of the wall surface 10 that forms the recess 1 dB becomes gradually smaller toward the inside in the radial direction. A recess 40 is formed in the recess 1 dB at the center in the circumferential direction of the second positioning surface 1 d 2. The recess 40 is a recess that is recessed inward in the radial direction. The first end surface 3c1 of the protrusion 3c is in contact with the first positioning surface 1d1 of the recess 1dB. A part of the inner surface 3c3 of the protrusion 3c is in contact with the second positioning surface 1d2 of the recess 1dB. The second end surface 3c2 of the protrusion 3c is in contact with the third positioning surface 1d3. The 3rd positioning surface 1d3 is a surface on the opposite side to the 1st positioning surface 1d1 in the circumferential direction among the wall surfaces 10 which form the hollow 1dB. The adhesive 11 is provided in a gap a between the wall surface 40A that forms the recess 40 and the inner side surface 3c3.

When the substrate 1B shown in FIG. 5 is used, the third positioning surface 1d3 of the recess 1dB is in contact with the second end surface 3c2 of the protrusion 3c. Therefore, when the substrate 1B is attached to the substrate fixing portion 3, the timepiece of the substrate 1B The filling operation into the recess 40 can be performed in a state in which the movement in the rotation direction and the counterclockwise direction is suppressed. Therefore, the adhesive 11 can be filled without worrying about the positional displacement of the substrate 1B in the circumferential direction, and the assembly work time of the encoder 100 can be shortened.

FIG. 6 is a diagram showing protrusions provided on the encoder according to the third modification of the first embodiment. In the protrusion 3cA shown in FIG. 6, a recess 50 is formed at the center in the circumferential direction of the inner surface 3c3 of the protrusion 3cA. The recess 50 is a recess that is recessed outward in the radial direction. The first end surface 3c1 is in contact with the first positioning surface 1d1. The inner side surface 3c3 of the protrusion 3cA is in contact with the second positioning surface 1d2. The second end surface 3c2 of the protrusion 3cA is in contact with the third positioning surface 1d3 of the recess 1d. The adhesive 11 is provided in the gap a between the wall surface 50A that forms the recess 50 and the second positioning surface 1d2.

By using the projection 3cA shown in FIG. 6, the third positioning surface 1d3 of the recess 1d is in contact with the second end surface 3c2 of the projection 3cA. Therefore, when the substrate 1 is attached to the substrate fixing portion 3, The filling operation into the recess 50 can be performed in a state in which the movement in the rotation direction and the counterclockwise direction is suppressed. Therefore, the adhesive 11 can be filled without worrying about the displacement of the substrate 1 in the circumferential direction, and the assembly work time of the encoder 100 can be shortened.

FIG. 7 is a diagram showing protrusions provided on the encoder according to the fourth modification of the first embodiment. The protrusion 3cB shown in FIG. 7 has a shape in which the width in the circumferential direction becomes gradually narrower toward the inside in the radial direction. The first end surface 3c1 of the protrusion 3cB is in contact with the first positioning surface 1d1 of the recess 1d. A part of the inner side surface 3c3 of the protrusion 3cB is in contact with the second positioning surface 1d2 of the recess 1d.

The adhesive 11 is provided in the gap a1 between the surface 10A and the second end surface 3c2, and further provided in the gap a2 between the surface 10B and the non-contact surface 3c3A. The surface 10A is a surface that faces the second end surface 3c2 of the protrusion 3cB in the wall surface 10 that forms the recess 1d. The non-contact surface 3c3A is a surface that is not in contact with the second positioning surface 1d2 of the recess 1d in the inner surface 3c3 of the protrusion 3cB. The surface 10B is a surface facing the non-contact surface 3c3A among the wall surfaces 10 forming the depression 1d.

By using the protrusion 3cB shown in FIG. 7, the contact area of the adhesive 11 to the protrusion 3cB is larger than the contact area of the adhesive 11 to the protrusion 3c shown in FIG. It becomes difficult to peel from. Therefore, the substrate 1 can be more firmly fixed to the substrate fixing portion 3.

FIG. 8 is a view showing a modification of the fitting structure of the substrate and three protrusions shown in FIG. In the encoder 100 shown in FIG. 8, the first end face 3c1 of the first protrusion 3c-1 among the three protrusions is the first end 1d-1 corresponding to the first protrusion 3c-1 among the three recesses. It contacts the first positioning surface 1d1. In the encoder 100 shown in FIG. 8, the second end surface 3c2 of the second protrusion 3c-2 among the three protrusions is a second recess 1d-2 corresponding to the second protrusion 3c-2 among the three recesses. In contact with the third positioning surface 1d3. Further, in the encoder 100 shown in FIG. 8, the adhesive 11 is provided at a position facing each of the first end surface 3c1 and the second end surface 3c2 of the third protrusion 3c-3 among the three protrusions.

According to the encoder 100 shown in FIG. 8, the adhesive 11 is in a state where the first protrusion 3c-1 and the second protrusion 3c-2 suppress the movement of the substrate 1 in the clockwise direction and the counterclockwise direction. Can be filled. Therefore, the adhesive 11 can be filled without worrying about the displacement of the substrate 1 in the circumferential direction, and the assembly work time of the encoder 100 can be shortened.

FIG. 9 is a view showing a modification of the protrusion shown in FIG. In the protrusion 300 shown in FIG. 9, an inclined surface 70 is formed at the tip in the axial direction. The inclined surface 70 has a function of guiding the substrate outer peripheral portion 1 c of the substrate 1 toward the radial center of the substrate fixing portion 3. By providing the inclined surface 70, when the substrate 1 is inserted into the space surrounded by the three protrusions 3c, the substrate 1 is not easily caught on the tip of the protrusion 3c, and the assembly work of the encoder 100 is facilitated.

Embodiment 2. FIG.
FIG. 10 is an external view of a servo motor according to the second embodiment. A servo motor 200 shown in FIG. 10 is a motor used in a machine tool such as a machining center, an NC lathe, a laser machine, an electric discharge machine, or the like. Servo motor 200 includes motor 150 and encoder 100 according to the first embodiment. The motor 150 includes a case 301, a bracket 8 provided at an end of the case 301, a rotor (not shown) provided in the case 301, and a shaft 302 provided in the rotor. In the servo motor 200, since the encoder 100 of the first embodiment is used, the diameters of the substrate fixing portion 3 and the substrate 1 are reduced, and the diameter of the cover 5 is accordingly reduced, so that the servo motor 200 as a whole can be further reduced in size. Can be achieved.

In the present embodiment, the adhesive 11 is used as a fixing member for the protrusion 3 c to the substrate 1. However, the fixing member is limited to the adhesive 11 as long as it is a member that can fix the protrusion 3 c to the substrate 1. For example, it may be a solder whose viscosity changes greatly by heat, or may be an elastic body such as a spring or rubber whose shape changes when an external force is applied.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1, 1A, 1B substrate, 1a first substrate surface, 1b second substrate surface, 1c substrate outer peripheral portion, 1d, 1dA, 1dB depression, 1d1, first positioning surface, 1d2, second positioning surface, 1d3, third positioning surface, 2 Electronic component, 3 substrate fixing part, 3a end part, 3b outer peripheral part, 3c, 3cA, 3cB, 300 protrusion, 3c-1 first protrusion, 3c-2 second protrusion, 3c-3 third protrusion, 3c1 first end face 3c2, second end surface, 3c3 inner surface, 3c3A non-contact surface, 3c4 tip, 5 cover, 5a bottom, 5b cylinder, 7 screws, 8 bracket, 10, 40A, 50A wall, 10A surface, 11 adhesive, 31 Corner, 40, 50 recess, 70 inclined surface, 100 encoder, 150, 200 servo motor, 301 case, 302 shaft, a a1, a2 gap.

Claims

A cylindrical substrate fixing part;
A protrusion extending in the axial direction from the corner, provided at a corner formed by an end of the substrate fixing portion in the axial direction and an outer peripheral portion of the substrate fixing portion;
A substrate having a substrate surface in contact with the end portion and a recess formed in an outer peripheral portion of the substrate surrounding the substrate surface and recessed from the outer periphery of the substrate toward the inner side in the radial direction of the substrate fixing portion. When,
A fixing member provided in a gap formed between the protrusion and the depression;
With
The wall surface forming the depression is
First positioning for determining the circumferential position of the substrate in contact with either the first end surface of the projection in the circumferential direction of the substrate fixing portion or the second end surface opposite to the first end surface Surface,
A second positioning surface that is in contact with the inner surface of the protrusion in the radial direction and determines the radial position of the substrate;
An encoder comprising:
The first end surface is in contact with the first positioning surface;
The encoder according to claim 1, wherein the gap is formed between the second end surface and a surface facing the second end surface among the wall surfaces forming the depression.
The depression is a shape in which the width in the circumferential direction of the wall surface forming the depression is gradually reduced toward the inside in the radial direction,
The gap is
Formed between the second end surface and a surface facing the second end surface among the wall surfaces forming the depression,
The non-contact surface that is not in contact with the second positioning surface among the inner side surfaces and a surface that faces the non-contact surface among the wall surfaces that form the depressions. Encoder described in.
The second positioning surface is formed with a recess that is recessed toward the inside in the radial direction,
The second end surface is in contact with a third positioning surface provided on a side opposite to the first positioning surface in the circumferential direction among the wall surfaces forming the depression,
The encoder according to claim 1, wherein the gap is formed between a wall surface that forms the recess and the inner surface.
The inner surface is formed with a recess that is recessed toward the outside in the radial direction,
The second end surface is in contact with a third positioning surface provided on a side opposite to the first positioning surface in the circumferential direction among the wall surfaces forming the depression,
The encoder according to claim 1, wherein the gap is formed between a wall surface that forms the recess and the second positioning surface.
The protrusion has a shape in which the width in the circumferential direction becomes gradually narrower toward the inside in the radial direction,
The gap is
Formed between the second end surface and a surface facing the second end surface among the wall surfaces forming the depression,
The non-contact surface that is not in contact with the second positioning surface among the inner side surfaces and a surface that faces the non-contact surface among the wall surfaces that form the depressions. Encoder described in.
The substrate fixing portion is provided with three protrusions,
The three protrusions are arranged away from each other in the circumferential direction,
The substrate is provided with three recesses corresponding to the three protrusions,
The encoder according to any one of claims 1 to 6, wherein the three recesses are arranged apart from each other in the circumferential direction.
The first end surface of the first protrusion among the three protrusions is
Of the three depressions, the first positioning surface of the first depression corresponding to the first protrusion is in contact with the first depression,
Of the three protrusions, the second end face of the second protrusion is
The encoder according to claim 7, wherein the third positioning surface provided on the opposite side to the first positioning surface of the second recess corresponding to the second protrusion among the three recesses is in contact with the third positioning surface.
9. The inclined surface for guiding the outer peripheral portion of the substrate toward the radial center of the substrate fixing portion is formed at the tip end portion of the projection in the axial direction. The encoder according to one item.
A servomotor comprising the encoder according to any one of claims 1 to 9 and a motor.