Rotational movement detection device

Abstract

A rotary motion detection device (10) which outputs a signal corresponding to a rotary motion of a rotary disk (12) coupled to a shaft (16), wherein a hub (14) is attached to the shaft (16), wherein the hub (14) is attached to a surface (24) of the turntable (12), and wherein one of the hub (14) and the shaft (16) is formed as a hole member (40) having a hole (42) formed therein, and the other is an inserted member (52) inserted into the hole (42), and wherein the hole element (40) has an inner circumference which is larger than an outer circumference of the inserted element (52), so that the shaft (16) is perpendicular to the turntable (12) without being limited by the hub (14), wherein the rotational movement detecting device (10) further comprises a positioning element (60) between a bottom surface (50) arranged at a bottom of the hole (42) and an end surface (56) of the inserted element (52) facing the bottom surface (50), and wherein the positioning element (60) bears against a first portion (62) of the bottom surface (50) and a second portion (64) of the end surface (56) and respective axis lines (A1, A3) of the turntable (12) and the shaft (16) coincide with one another.

Description

BACKGROUND OF THE INVENTIONField of the Invention:The present invention relates to a rotary motion detecting device configured to output a signal corresponding to a rotary motion of a rotary disk coupled to a shaft, such as a rotary encoder.Description of Related Art:International Publication No. WO 2010 / 119 513 A1 discloses a rotary motion detection device (a rotary encoder) that outputs a signal corresponding to a rotary motion of a rotary disk coupled to a shaft. In this rotation detection device, a hub is fixed to the rotary disk having slots, and the shaft, for example, an output shaft of a motor or a rotation shaft coupled to the output shaft, is fitted into the hub.JP 2018-91 739 A discloses a rotation detection device having a rotating disk fixed to a hub with a through hole by an adhesive. A shaft body is inserted in the through hole of the hub so as to protrude from both ends of the through hole.JP S61-236 924 A, DE 697 29 907 T2, DE 698 28 764 T2 and DE 10 2018 203 399 A1 disclose further relevant prior art.Brief Description of the InventionWhen the hub is fixed to the rotating disk with an adhesive, and when the thickness of the adhesive is nonuniform, the axis line of the rotating disk is inclined with respect to the axis line of the hub. The axis line of the rotary disk is then also inclined with respect to the axis line of the shaft. This causes the height of the outer periphery of the rotating disk to be uneven and then the surface of the rotating disk to wobble during rotation. Small-format rotary encoders are particularly susceptible to surface tumbling of the rotary disk. Surface tumbling has a disadvantageous effect on the accuracy of the rotary encoders.Accordingly, it is an object of the present invention to provide a rotation movement detecting device capable of preventing surface dewing.A first aspect of the present invention is directed to a rotation detection device according to claim 1, which outputs a signal corresponding to a rotation of a rotary disk coupled to a shaft, wherein a hub is fixed to the shaft, wherein the hub is fixed to a surface of the rotary disk, and wherein one of the hub and the shaft is a hole member including a hole formed therein, and the other is an inserted member inserted into the hole, and wherein the hole member has an inner circumference larger than an outer circumference of the inserted member so that the shaft is perpendicular to the rotary disk without being limited by the hub.A second aspect of the present invention is directed to a rotational movement detecting apparatus according to claim 2.Advantageous embodiments are contained in the dependent claims 3 to 7.According to the present invention, the shaft can be perpendicular to the rotary disk without being limited by the hub, and it is therefore possible to prevent surface wobbling of the rotary disk.The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which a preferred embodiment of the present invention is shown by way of illustration.Brief Description of the DrawingsFIG. 1 is a diagram illustrating the configuration of a rotation motion detecting apparatus according to a first embodiment, which does not show all features of the present invention; FIG. 2 is a diagram showing the configuration of a first non-inventive specific example of the first embodiment in a cross section parallel to the axis lines; FIG. 3 is a diagram showing another implementation of the first non-inventive specific example of the first embodiment in a cross section parallel to the axis lines; FIG. 4 is a diagram showing the configuration of a second non-inventive specific example of the first embodiment in a cross section orthogonal to the axis lines; FIG. 5 is a diagram showing the configuration of a third specific example of the first embodiment according to the present invention in a cross section parallel to the axis lines; FIG. 6 is a diagram showing the configuration of a fourth specific example of the first embodiment according to the present invention in a cross section parallel to the axis lines; FIG. 7 is a diagram showing the configuration of a fifth specific example of the first embodiment according to the present invention in a cross section parallel to the axis lines; FIG. 8 is a diagram showing the configuration of a sixth non-inventive specific example according to a second embodiment in a cross section parallel to the axis lines; FIG. 9 is a diagram showing the configuration of a seventh non-inventive specific example of the second embodiment in a cross section orthogonal to the axis lines; FIG. 10 is a diagram showing the configuration of an eighth specific example of the second embodiment according to the present invention in a cross section parallel to the axis lines; FIG. 11 is a diagram showing the configuration of a ninth specific example of the second embodiment according to the present invention in a cross section parallel to the axis lines; and FIG. 12 is a diagram showing the configuration of a tenth specific example of the second embodiment according to the present invention in a cross section parallel to the axis lines.DESCRIPTION OF THE PREFERRED EMBODIMENTSThe rotational motion detecting apparatus according to the present invention will now be described in detail below in connection with preferred embodiments with reference to the accompanying drawings.[1. First Embodiment][1.1. Rotation Motion Detecting Device 10]The basic structure of a rotation motion detecting device 10 will be described with reference to FIGS. 1 and 2. The rotation detection device 10 includes a rotating disk 12, a hub 14, a shaft 16, a light emitting element 18, and a light receiving element (an optical receiver) 20.The rotary disk 12 is made of glass, resin or metal. The rotary disk 12 is in the form of a circular plate and has a plurality of slits 22 arranged at equal intervals along its circumferential direction. Note that FIG. 1 shows only one slot 22. The hub 14 is made of resin or metal. The hub 14 has an opening of the hole 42 at one end in the direction of its axis line and has a bonding surface 28 at the other end in the direction of its axis line. The hole 42 may be provided with a bottom or pass from one end to the other end in the direction of the axis line of the hub 14. The composite surface 28 of the hub 14 is secured to a surface 24 of the rotating disk 12 with an adhesive 30. The shaft 16 is made of metal. One end of the shaft 16 is inserted into the hole 42 of the hub 14. The shaft 16 may be an object whose rotational motion is to be detected (e.g., an output shaft of a motor or the like), or a rotational shaft coupled to an object to be detected via a clutch or the like. The shaft 16 is perpendicular to the rotating disk 12, and the axis line A 1 of the rotating disk 12 and the axis line A 3 of the shaft 16 coincide with each other. The hub 14 and the shaft 16 are connected to each other by a fastener (see the following section [1.2]).The light emitting element 18 includes a light emitting device such as an LED, etc. The light receiving element 20 includes a light receiving device such as a photodiode, etc. The light emitting element 18 and the light receiving element 20 face each other with the rotating disk 12 interposed therebetween.In cases where the shaft 16 is an output shaft of a motor, etc., the components other than the shaft 16 constitute a hollow shaft type rotary encoder. In the other cases where the shaft 16 is connected to an output shaft of a motor, etc. via a clutch or the like, the rotation detection device 10 is a shaft-type rotary encoder.The operations of the rotation detecting device 10 will now be described. When the rotating shaft (shaft 16) of a motor or the like rotates, the rotating disk 12 rotates about the axis lines A 1, A 3. Then, the plurality of slits 22 sequentially pass between the light emitting element 18 and the light receiving element 20. Otherwise, the light emitted from the light emitting element 18 is interrupted by the rotating disk 12 when the light emitting element 18, the light receiving element 20, and a slit 22 are not aligned on a straight line. The light receiving element 20 outputs an ON signal when receiving light and outputs an OFF signal when not receiving light.[1.2. Structure for Fixing Hub 14 (Hole Member 40) and Shaft 16 (Inserted Member 52)]The structures for mounting the hub 14 and the shaft 16 will be explained by way of first to fifth specific examples shown in FIGS. 2 to 7. In the first to fifth specific examples, both the inner circumferential shape of the hole 42 of the hub 14 and the outer circumferential shape of the shaft 16 are substantially circular. An inner diameter R 2 of the hole 42 of the hub 14 is formed larger than an outer diameter R 1 of the shaft 16, so that the shaft 16 can be adjusted perpendicularly to the rotary disk 12 without being limited by the hub 14. Because the inner diameter R2 is greater than the outer diameter R1, the angle of the shaft 16 with respect to the rotary disk 12 can be adjusted before the shaft 16 inserted into the hole 42 is fixed to the hub 14.[1.2.1. First Specific Example]With reference to FIGS. 2 and 3, a first specific example will be described using a thermosetting resin 32 as the fastening member. Since the inner diameter R 2 of the hole 42 of the hub 14 is larger than the outer diameter R 1 of the shaft 16, a space is formed between an inner circumferential surface 44 of the hub 14 and an outer circumferential surface 54 of the shaft 16 when the shaft 16 is inserted into the hole 42. In the first specific example in which the shaft 16 is inserted into the hole 42 of the hub 14, the thermosetting resin 32, e.g., epoxy resin, etc., is injected into the space between the hub 14 and the shaft 16. The thermosetting resin 32 is injected into the inside of the hole 42 from a resin injection hole 48 passing through the hub 14 from an outer circumferential side to an inner circumferential side of the hub 14.The thermosetting resin 32 fixes the hub 14 and the shaft 16 to each other without the inner circumferential surface 44 of the hub 14 and the outer circumferential surface 54 of the shaft 16 being in contact along the depth direction of the hole 42. More specifically, the thermosetting resin 32 fixes the hub 14 and the shaft 16 to each other without the inner circumferential surface 44 of the hub 14 and the outer circumferential surface 54 of the shaft 16 being in contact. However, it should be noted that the thermosetting resin 32 may fix the hub 14 and the shaft 16 to each other, with the inner circumferential surface 44 of the hub 14 and the outer circumferential surface 54 of the shaft 16 in point contact with each other or in line contact with each other along the circumferential direction of the inner circumferential surface 44 of the hub 14.As shown in FIGS. 2 and 3, the shaft 16 is perpendicular to the rotary disk 12, and the rotary disk 12, the hub 14, and the shaft 16 are fixed to each other. In this state, the axis line A 1 of the rotating disk 12 and the axis line A 3 of the shaft 16 are located together. As shown in FIG. 2, when the thickness of the adhesive 30 is uniform, the axis line A 2 of the hub 14 coincides with the axis line A 1 of the rotary disk 12 and the axis line A 3 of the shaft 16. On the other hand, as shown in FIG. 3, when the thickness of the adhesive 30 is not uniform, the axis line A 2 of the hub 14 is inclined with respect to the axis line A 1 of the rotating disk 12 and the axis line A 3 of the shaft 16.When the inner circumferential surface 44 of the hub 14 and the outer circumferential surface 54 of the shaft 16 are in contact with each other along the depth direction of the hole 42, the axis line A 3 of the shaft 16 coincides with or is parallel to the axis line A 2 of the hub 14. If the thickness of the adhesive 30 is non-uniform and the axis line A 2 of the hub 14 is inclined with respect to the axis line A 1 of the rotating disk 12, then the axis line A 3 of the shaft 16 is also inclined with respect to the axis line A 1 of the rotating disk 12. In this case, when the shaft 16 rotates and while the rotary disk 12 rotates, the rotary disk 12 will greatly wobble. In contrast, in the case of the first specific example shown in FIGS. 2 and 3, the axis line A 1 of the rotating disk 12 and the axis line A 3 of the shaft 16 coincide with each other. This prevents the surface from wobbling as the shaft 16 rotates and as the rotary disk 12 rotates. The specific examples shown below also provide the same effect.[1.2.2. Second Specific Example]Referring to FIG. 4, a second specific example will be described using three or more screws 34 as the fastening member. The screws 34 may be pins. In this second specific example in which the shaft 16 is inserted into the hole 42 of the hub 14, the three screws 34 are pressed from three directions from the outer circumferential side to the inner circumferential side of the hub 14. The three screws 34 are disposed at the same height position. The distal ends of the individual screws 34 abut flat surfaces 58 formed on the outer circumferential surface 54 of the shaft 16. The shaft 16 is thus supported at three points. Note that it is not always necessary to form the flat surfaces 58 on the outer circumferential surface 54 of the shaft 16.As in the first specific example, the bolts 34 fasten the hub 14 and the shaft 16 to each other without the inner circumferential surface 44 of the hub 14 and the outer circumferential surface 54 of the shaft 16 being in contact along the depth direction of the hole 42. More specifically, the bolts 34 fasten the hub 14 and the shaft 16 to each other without the inner circumferential surface 44 of the hub 14 and the outer circumferential surface 54 of the shaft 16 being in contact with each other. However, it should be noted that the bolts 34 may fix the hub 14 and the shaft 16 to each other with the inner circumferential surface 44 of the hub 14 and the outer circumferential surface 54 of the shaft 16 in contact with each other at a point or along a line along the circumferential direction of the inner circumferential surface 44 of the hub 14.[1.2.3. Third Specific Example]Referring to FIG. 5, a third specific example will be described. The third specific example is a modification of the first specific example. The basic structure of the third specific example is the same as the structure of the first specific example. The differences between the third specific example and the first specific example will now be described. The rotation detection device 10 of the third specific example includes a spherical body 60 disposed between a bottom surface 50 disposed at the bottom of the hole 42 of the hub 14 and an end surface 56 of the inserted member 52 (the shaft 16) facing the bottom surface 50. The spherical body 60 is a positioning member.The bottom surface 50 of the hub 14 has a concavity formed in its center, the length of the concavity in the depth direction is shorter than the radius of the spherical body 60, and the diameter of its opening is shorter than the diameter of the spherical body 60. The first recess 62 has a circular shape or a spherical shape. Similarly, the end face 56 of the shaft has a 16 concavity formed at its center, the length of the concavity in the depth direction is shorter than the radius of the spherical body 60 and the diameter of its opening is shorter than the diameter of the spherical body 60. The second recess 64 has a circular shape or a spherical shape.When the hub 14 is fixed to the rotary disk 12, the first recess 62 is positioned on the axis line A 1 of the rotary disk 12. Before the shaft 16 is fixed to the hub 14, a part of the spherical body 60 is fitted into the first recess 62, and another part of the spherical body 60 is fitted into the second recess 64. When the spherical body 60 is fitted into the first recess 62 and the second recess 64, a space remains between the bottom surface 50 of the hub 14 and the end surface 56 of the shaft 16. In this state, the inclination angle of the shaft 16 with respect to the rotary disk 12 is adjusted appropriately to achieve centering of the axis line A 1 of the rotary disk 12 and the axis line A 3 of the shaft 16. In addition, the axis line A 1 of the rotating disk 12 and the axis line A 3 of the shaft 16 are set perpendicularly. Thereafter, the thermosetting resin 32 is filled between the shaft 16 and the hub 14, thereby fixing the shaft 16 and the hub 14 to each other.[1.2.4. Fourth Specific Example]Referring now to FIG. 6, a fourth specific example will be described. The fourth specific example is a modification of the first and third specific examples. In the third specific example described above, the first recess 62 was formed in the bottom surface 50 of the hub 14, and the spherical body 60 was fitted into the first recess 62. In contrast, in the fourth specific example, a bulge is formed in the center of the bottom surface 50 of the hub 14. This bulge is referred to as a protrusion 66. The height of the protrusion 66 is greater than the depth of the second recess 64 formed in the shaft 16. The second recess 64 in the fourth specific example is mortar-shaped. Fig. 6 shows the protrusion 66 and the second recess 64 as if they were spaced apart from each other, but they actually abut each other.As the protrusion 66 abuts the second recess 64, a space remains between the bottom surface 50 of the hub 14 and the end surface 56 of the shaft 16. In this state, the inclination angle of the shaft 16 relative to the rotary disk 12 is adjusted appropriately to achieve centering of the axis line A 1 of the rotary disk 12 and the axis line A 3 of the shaft 16. Further, the axis line A 1 of the rotating disk 12 and the axis line A 3 of the shaft 16 are set perpendicularly. Thereafter, the thermosetting resin 32 is filled between the shaft 16 and the hub 14, thereby fixing the shaft 16 and the hub 14 to each other.[1.2.5. Fifth Specific Example]Referring now to FIG. 7, a fifth specific example will be described. The fifth specific example is a modification of the first, third, and fourth specific examples. In the fourth specific example described above, the bulge (the protrusion 66) was formed in the center of the bottom surface 50 of the hub 14, and the concavity (the second recess 64) was formed in the center of the end surface 56 of the shaft 16. In contrast, as shown in this fifth specific example, a concavity (a first recess 62) may be formed in the center of the bottom surface 50 of the hub 14 and a bulge (a protrusion 66) may be formed in the center of the end surface 56 of the shaft 16. FIG. 7 shows the protrusion 66 and the first recess 62 as if they were spaced apart from each other, but the two actually abut each other.[1.2.6. Other Examples]The third to fifth specific examples correspond to modifications of the first specific example. However, the third to fifth specific examples may be applied to the second specific example in which the bolts 34 form the fastening member.[2. Second Embodiment]In the rotation detection device 10 of the first embodiment, the hub 14 is the hole member 40 and the shaft 16 is the inserted member 52. on the other hand, as shown in the rotation detection devices 10 shown in FIGS. 8 to 12, the shaft 16 may be the hole member 40 having the hole 42 and the hub 14 may be the inserted member 52 inserted into the hole 42.The first to fifth specific examples of the first embodiment can also be applied to a second embodiment. Figs. 8 to 12 show examples thereof. A sixth specific example shown in FIG. 8 corresponds to the first specific example of the first embodiment shown in FIG. 2. A seventh specific example shown in FIG. 9 corresponds to the second specific example of the first embodiment shown in FIG. 4. An eighth specific example shown in FIG. 10 corresponds to the third specific example of the first embodiment shown in FIG. 5. A ninth specific example shown in FIG. 11 corresponds to the fourth specific example of the first embodiment shown in FIG. 6. A tenth specific example shown in FIG. 12 corresponds to the fifth specific example of the first embodiment shown in FIG. 7.The sixth to tenth specific examples are the same as the first to fifth specific examples, respectively, except that the hole member 40 is the shaft 16 and the inserted member 52 is the hub 14. Accordingly, the components are denoted by the same reference numerals and will not be described again here.[3. Aspects Derivable from Embodiments]Aspects graspable from the above-described embodiments and modifications will be presented below.One aspect is directed to the rotational motion detection device 10 that outputs a signal corresponding to rotational motion of the rotary disk 12 coupled to the shaft 16, the hub 14 is fixed to the shaft 16, the hub 14 is fixed to a surface 24 of the rotary disk 12, and one of the hub 14 and the shaft 16 is a hole member 40 including a hole 42 formed therein and the other is an inserted member 52 inserted into the hole 42, and the hole member 40 has an inner circumference (inner diameter R 2) larger than an outer circumference (outer diameter R 1) of the inserted member 52 such that the shaft 16 is perpendicular to the rotary disk 12 without being limited by the hub 14.According to the above configuration, the inner circumference of the hole member 40, e.g., the inner diameter R 2 of the hub 14, is formed larger than the outer circumference of the inserted member 52, e.g., the outer diameter R 1 of the shaft 16. With this structure, even when the hub 14 is fixed at an angle to the rotary disk 12, the shaft 16 can be set perpendicular to the rotary disk 12 without being affected by the inclination of the hub 14. In this way, this configuration reduces surface wobbling of the rotary disk 12 because the shaft 16 is set perpendicular to the rotary disk 12 without being limited by the hub 14.According to the aspect, the rotation motion detection device 10 may further include a fixing member (the thermosetting resin 32, the screws 34) that fixes the hole member 40 and the inserted member 52 to each other without the inner circumferential surface 44 of the hole member 40 (e.g., the hub 14) and the outer circumferential surface 54 of the inserted member 52 (e.g., the shaft 16) being in contact with each other along a depth direction of the hole 42.According to this configuration, the inner circumferential surface 44 of the hole member 40 (e.g., the hub 14) and the outer circumferential surface 54 of the inserted member 52 (e.g., the shaft 16) do not contact each other along the depth direction of the hole 42, and therefore it is possible to independently adjust the inclination of the hub 14 and the inclination of the shaft 16 with respect to the rotary disk 12. With this structure, even when the hub 14 is fixed at an angle to the rotary disk 12, the shaft 16 can be adjusted perpendicularly to the rotary disk 12 without being affected by the inclination of the hub 14. This reduces the surface dewing of the rotary disk 12.In one aspect, the fastener (the thermosetting resin 32, the screws 34) can fasten the hole member 40 and the inserted member 52 to each other without the inner circumferential surface 44 of the hole member 40 (e.g., the hub) and the outer circumferential surface 54 of the inserted member 52 (e.g., the shaft 16) being in contact with each other.According to this configuration, the inner circumferential surface 44 of the hole member 40 (e.g., the hub 14) and the outer circumferential surface 54 of the inserted member 52 (e.g., the shaft 16) do not contact each other, and therefore it is possible to independently adjust the inclination of the hub 14 and the inclination of the shaft 16 with respect to the rotary disk 12. With this structure, even when the hub 14 is fixed at an angle to the rotary disk 12, the shaft 16 can be set perpendicular to the rotary disk 12 without being affected by the inclination of the hub 14. This reduces the surface dewing of that of the rotary disk 12.In one aspect, the fastener may be a thermosetting resin 32 filled in a space between the hole member 40 (e.g., the hub 14) and the inserted member 52 (e.g., the shaft 16).In one aspect, the fastener may include screws 34 or pins inserted from an outer circumferential side to an inner circumferential side of the hole member 40 (e.g., the hub 14) to abut the outer circumferential surface 54) of the flat surfaces 58) of the inserted member 52 (e.g., the shaft 16).In one aspect, the rotation detection device 10 may further include a positioning member (the spherical body 60) between the bottom surface 50 disposed at a bottom of the hole 42 and an end surface 56 of the inserted member 52 (e.g., the shaft 16) facing the bottom surface 50, wherein the positioning member (the spherical body 60) may abut a first portion (e.g., the first recess 62) of the bottom surface 50 and a second portion (e.g., the second recess 64) of the end surface 56, and the respective axis lines (the axis lines A 1, A 3) of the rotating disk 12 and the shaft 16 coincide with each other.In one aspect, the positioning member may be a spherical body 60, and a first recess 62 in which the spherical body 60 is fitted may be formed in the first portion of the bottom surface 50, and a second recess in which the spherical body is fitted may be formed in the second portion of the end surface 56.According to the above configuration, the hole member 40 (e.g., the hub 14) and the inserted member 52 (e.g., the shaft 16) are pivotable relative to each other. When the first recess 62 and the second recess 64 are positioned such that the spherical body 60 is positioned on the axis line A 1 of the rotating disk 12 and the axis line A 3 of the shaft 16, the shaft 16 can be pivoted on the spherical body 60 to achieve centering of the rotating disk 12 and the shaft 16.In one aspect, one of the bottom surface 50 disposed at a bottom of the hole 42 and the end surface 56 of the inserted member 52 (e.g., the shaft 16) facing the bottom surface 50 may have a recess (the first recess 62, the second recess 64), and another may have a protrusion 66, and the recess (the first recess 62, the second recess 64), and the protrusion 66 may abut each other, and respective axis lines (the axis lines A 1, A 3) of the rotating disk and the shaft may coincide with each other.According to the above configuration, the hole member 40 (e.g., the hub 14) and the inserted member 52 (e.g., the shaft 16) can swing with respect to each other. When the recess (the first recess 62, the second recess 64), and the protrusion 66 are positioned on the axis line A 1 of the rotating disk 12 and the axis line A 3 of the shaft 16, the shaft 16 may swing on the protrusion 66 to achieve centering of the rotating disk 12 and the shaft 16.

Claims

A rotation detection device (10) that outputs a signal corresponding to a rotation of a rotary disk (12) coupled to a shaft (16), wherein a hub (14) is fixed to the shaft (16), wherein the hub (14) is fixed to a surface (24) of the rotary disk (12), and wherein one of the hub (14) and the shaft (16) is formed as a hole member (40) having a hole (42) formed therein and the other is an inserted member (52) inserted into the hole (42), and wherein the hole member (40) has an inner circumference larger than an outer circumference of the inserted member (52) so that the shaft (16) is perpendicular to the rotary disk (12) without being limited by the hub (14), wherein the rotational motion detecting device (10) further comprises a positioning member (60) between a bottom surface (50) disposed at a bottom of the hole (42) and an end surface (56) of the inserted member (52) facing the bottom surface (50), and wherein the positioning member (60) abuts a first portion (62) of the bottom surface (50) and a second portion (64) of the end surface (56), and respective axis lines (A1, A3) of the rotating disk (12) and the shaft (16) coincide with each other.A rotation detection device (10) that outputs a signal corresponding to a rotation of a rotary disk (12) coupled to a shaft (16), wherein a hub (14) is fixed to the shaft (16), wherein the hub (14) is fixed to a surface (24) of the rotary disk (12), and wherein one of the hub (14) and the shaft (16) is formed as a hole member (40) having a hole (42) formed therein and the other is an inserted member (52) inserted into the hole (42), and wherein the hole member (40) has an inner circumference larger than an outer circumference of the inserted member (52) so that the shaft (16) is perpendicular to the rotary disk (12) without being limited by the hub (14), one of a bottom surface (50), which is disposed at a bottom of the hole (42) and an end surface (56) of the inserted member (52) facing the bottom surface (50) has a recess (62, 64) and another has a protrusion (66), and wherein the recess (62, 64) and the protrusion (66) abut each other, and respective axis lines (A1, A3) of the rotary disk (12) and the shaft (16) coincide with each other.The rotation detection device (10) according to claim 1 or 2, further comprising a fixing member (32, 34) that fixes the hole member (40) and the inserted member (52) to each other without an inner circumferential surface (44) of the hole member (40) and an outer circumferential surface (54) of the inserted member (52) being in contact with each other along a depth direction of the hole (42).The rotation detection device (10) according to claim 3, wherein the fixing member (32, 34) fixes the hole member (40) and the inserted member (52) to each other without the inner circumferential surface (44) of the hole member (40) and the outer circumferential surface (54) of the inserted member (52) being in contact with each other.The rotation detection device (10) according to claim 3 or 4, wherein the fixing member (32, 34) is a thermosetting resin filled in a space between the hole member (40) and the inserted member (52).The rotation detection device (10) according to claim 3 or 4, wherein the fixing member (32, 34) includes screws or pins inserted from an outer circumferential side to an inner circumferential side of the hole member (40) to abut on the outer circumferential surface (54) of the inserted member (52).The rotation detection device (10) according to claim 1, wherein the positioning member (60) is a spherical body, and a first recess in which the spherical body is fitted is formed in the first portion (62) of the bottom surface (50), and a second recess in which the spherical body is fitted is formed in the second portion (64) of the end surface (56).

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