JP2021042803A - Power generation unit and bearing unit - Google Patents

Abstract

To provide a power generation unit on which a larger cover may be applied even in a case where there is a limit in a space where the cover is arranged.SOLUTION: A power generation unit is provided between a bearing and a large-diameter part of a rotational shaft. The rotational shaft is arranged on the inner peripheral side of a housing and rotatable around an axial core, in which the large-diameter part and a small-diameter part having a smaller outer diameter than that of the large-diameter part are arranged along an axial direction of the axial core. The bearing supports the small-diameter part. The power generation unit comprises a plate-shaped cover that is fixed to an outer ring included in the bearing, extends inward in a radial direction, and is provided with a component including a power generation coil. A radial inside end of the cover is located radially inside the outer peripheral surface of the large-diameter part.SELECTED DRAWING: Figure 6

Description

The present disclosure relates to a power generation unit and a bearing unit.

For example, in a bearing device that supports an axle of a vehicle, a spacer equipped with a sensor may be provided adjacent to the bearing device in order to detect whether or not an abnormality has occurred in the bearing device (for example, Patent Documents). 1). A power generation component that supplies electric power to the sensor is mounted on the spacer of Patent Document 1. As described above, some of the spacers are equipped with various parts such as sensors and power generation parts.

Japanese Unexamined Patent Publication No. 2003-307435

Of the parts mounted on the spacers, for example, focusing on the power generation parts, there are merits such as increasing the power generation capacity by increasing the number of power generation parts or increasing the number of power generation parts. It is preferable to increase the size and number of parts. However, if the space for arranging the spacers is limited, it may be difficult to increase the size of the spacers.

The present disclosure has been made in view of the above, and an object of the present disclosure is to provide a power generation unit and a bearing unit having a larger spacer even when the space for arranging the spacer is limited.

In order to achieve the above object, in the power generation unit of one aspect of the present disclosure, the large diameter portion and the small diameter portion whose outer diameter is smaller than the large diameter portion are arranged on the inner peripheral side of the housing in the axial direction of the axis. A power generation unit provided between a bearing that supports the small diameter portion of a rotary shaft that is located along the axis and can rotate about the axis, and the large diameter portion, and is provided on an outer ring included in the bearing. A plate-shaped cover that is fixed and extends inward in the radial direction and is provided with a component including a power generation coil is provided, and the radially inner end of the cover is located radially inward with respect to the outer peripheral surface of the large diameter portion.

As described above, since the radial inner end of the cover, which is a part of the spacer, is located radially inside the outer peripheral surface of the large-diameter portion, the radial length of the cover can be set larger. .. Therefore, since the size of the cover can be increased, it is possible to increase the number of parts such as the power generation coil mounted on the cover or to make the cover larger. In this way, even if the space for arranging the cover (seat) is limited, a larger cover (seat) can be provided.

A desirable embodiment of the power generation unit is a power generation unit further including a magnet that faces the power generation coil in the axial direction, and the bearing is formed on an outer ring fixed to the housing and a small diameter portion of the rotating shaft. It has an inner ring to be fixed and a rolling element provided between the outer ring and the inner ring, and the radial outer end of the magnet is radially outer than the radial outer end of the inner ring of the bearing. It is desirable that it is located and aligned axially with the radial outer end of the power generation coil. As a result, the length in the radial direction of the magnet can be set to be larger, so that the magnet can be made larger. Therefore, the power generation capacity generated by the power generation coil and the magnet can be further increased.

A desirable embodiment of the power generation unit is a power generation unit further including a retainer and a spacer for sandwiching the magnet, wherein the large diameter portion and the small diameter portion are located adjacent to each other in the axial direction, and the large diameter portion and the large diameter portion. A flat first wall extending in the radial direction is provided at a boundary portion with the small diameter portion, and a flat second wall extending in the radial direction is provided on the inner ring at a distance from the first wall in the axial direction. Is provided, and between the first wall and the second wall, a flat third wall extending in the radial direction and in contact with the first wall is located on the opposite side of the third wall in the axial direction. The retainer having a flat fourth wall extending in the radial direction, the flat plate-shaped spacer extending in the radial direction and in contact with the second wall, and the magnet sandwiched between the spacer and the fourth wall. And, it is desirable to be provided. Since the magnet rotates together with the rotating shaft and easily shakes in the axial direction during rotation, it is difficult to maintain the degree of orthogonality (orthogonality) with the axis. Therefore, by flattening the spacer and the fourth wall so as to extend in the radial direction, the accuracy of the degree of orthogonality (orthogonality) between the extending direction of the magnet and the axis is improved. As a result, when the magnet rotates, the degree of orthogonality between the power generation coil and the magnet is improved, so that the power generation capacity generated by the power generation coil and the magnet can be further increased.

As a desirable aspect of the power generation unit, it is desirable that the first wall and the radial inner end of the cover are arranged apart from each other in the axial direction. As a result, when the first wall of the rotating shaft rotates, there is an advantage that the first wall and the cover are less likely to come into contact with each other. The separation distance between the first wall and the inner end in the radial direction of the cover is preferably equal to or greater than the amount of axial displacement between the outer ring and the inner ring of the bearing when the rotating shaft rotates.

Further, in the bearing unit of one aspect of the present disclosure, the bearing unit is rotatable about the axis, and the large diameter portion and the small diameter portion having an outer diameter smaller than the large diameter portion are formed along the axial direction of the axial center. Provided between a rotating shaft located, an outer ring fixed to a housing located radially outside the rotating shaft, an inner ring fixed to the small diameter portion of the rotating shaft, and the outer ring and the inner ring. A bearing having a rolling element, and a plate-shaped cover fixed to the outer ring and extending inward in the radial direction and provided with parts are provided, and the radial inner end of the cover is the outer periphery of the large diameter portion. It is located radially inside the surface.

As described above, since the radial inner end of the cover is located radially inside the outer peripheral surface of the large-diameter portion, the radial length of the cover can be set larger. Therefore, it is possible to increase the number of parts such as the power generation coil mounted on the cover, or to make the parts larger. In this way, even if the space for arranging the cover (seat) is limited, a larger cover (seat) can be provided.

As a preferred embodiment of the bearing unit, the component includes a power generation coil, and a magnet extending in the radial direction and axially facing the power generation coil is provided on the side of the inner ring in the axial direction. The radial outer end of the bearing is located radially outer of the radial outer end of the inner ring of the bearing and is axially aligned with the radial outer end of the power generation coil. As a result, the length in the radial direction of the magnet can be set to be larger, so that the magnet can be made larger. Therefore, the power generation capacity generated by the power generation coil and the magnet can be further increased.

As a desirable embodiment of the bearing unit, the large-diameter portion and the small-diameter portion are located adjacent to each other in the axial direction, and a flat third portion extending in the radial direction is provided at the boundary between the large-diameter portion and the small-diameter portion. One wall is provided, and the inner ring is provided with a flat second wall located axially separated from the first wall and extending in the radial direction, and is provided between the first wall and the second wall. Retainer having a flat third wall extending in the radial direction and in contact with the first wall, and a flat fourth wall extending in the radial direction and located on the opposite side of the third wall in the axial direction. A flat plate-shaped spacer extending in the radial direction and contacting the second wall, and the magnet sandwiched between the spacer and the fourth wall are provided. Since the magnet rotates together with the rotating shaft and easily shakes in the axial direction during rotation, it is difficult to maintain the degree of orthogonality (orthogonality) with the axis. Therefore, by flattening the spacer and the fourth wall so as to extend in the radial direction, the accuracy of the degree of orthogonality (orthogonality) between the extending direction of the magnet and the axis is improved. As a result, when the magnet rotates, the degree of orthogonality between the power generation coil and the magnet is improved, so that the power generation capacity generated by the power generation coil and the magnet can be further increased.

As a preferred embodiment of the bearing unit, the first wall and the radial inner end of the cover are arranged apart in the axial direction. As a result, when the first wall of the rotating shaft rotates, there is an advantage that the first wall and the cover are less likely to come into contact with each other. The separation distance between the first wall and the inner end in the radial direction of the cover is preferably equal to or greater than the amount of axial displacement between the outer ring and the inner ring of the bearing when the rotating shaft rotates.

According to the present disclosure, since the radial inner end of the cover is located radially inside the outer peripheral surface of the large diameter portion, a larger cover can be provided even when the space for arranging the cover is limited. ..

FIG. 1 is a perspective view of the bearing with a sensor of the present embodiment. FIG. 2 is an exploded perspective view of the bearing with a sensor of the present embodiment. FIG. 3 is an exploded perspective view of the bearing with a sensor of the present embodiment. FIG. 4 is a plan view showing a configuration example of the cover and the coil substrate of the present embodiment. FIG. 5 is a cross-sectional view of a rotating shaft, a bearing with a sensor, and a housing. FIG. 6 is an enlarged cross-sectional view of a part of FIG. FIG. 7 is an enlarged cross-sectional view of a part of FIG. FIG. 8 is a cross-sectional view of the retainer, magnet and spacer.

An embodiment (embodiment) for carrying out the invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

FIG. 1 is a perspective view of the bearing with a sensor of the present embodiment. 2 and 3 are exploded perspective views of the bearing with a sensor of the present embodiment. FIG. 2 is a view of the bearing 100 with a sensor viewed from the cover 10 side, and FIG. 3 is a view of the bearing 100 with a sensor viewed from the bearing 120 side. As shown in FIGS. 1 to 3, the bearing 100 with a sensor includes a power generation unit 110 with a sensor (power generation unit) and a bearing 120. A power generation unit 110 with a sensor is attached to one side surface of the bearing 120. As shown in FIGS. 2 and 3, the power generation unit 110 with a sensor (power generation unit) includes a cover 10, a coil board 20 (power generation coil, parts), a magnet 31, a spacer 33, and a circuit board 40 (parts). A seal material 60 and a retainer 50 (see FIG. 5 and the like) described later are provided. The "parts" according to the present embodiment include at least a power generation coil such as a coil board 20 and an electronic component such as a circuit board 40. However, in the present invention, the "parts" are not limited to these power generation coils and electronic parts, and various electric parts, component parts, and the like are also included in the "parts".

The cover 10 has a ring-shaped top plate 12 and a tubular side plate 11 provided on the outer periphery of the top plate 12. The cover 10 is made of a magnetic material such as silicon steel plate, carbon steel (JIS standard SS400 or S45C), martensitic stainless steel (JIS standard SUS420) or ferritic stainless steel (JIS standard SUS430).

As shown in FIG. 3, the circuit board 40 (component) and the coil board 20 are attached to the back surface 12a of the top plate 12. Here, the back surface 12a is the second surface on the side facing the bearing 120. The surface 12d of the top plate 12 described later with reference to FIG. 5 and the like is the first surface. The circuit board 40 includes a power supply board 41 and a sensor board 42. For example, as shown in FIGS. 1 and 2, a bolt 19B made of a non-magnetic material such as brass is fastened to a female screw hole formed in the top plate 12, so that the power supply board 41 and the sensor board 42 are attached to the top plate 12. It is fixed. As shown in FIGS. 1 and 2, the bolt 19B has a length that does not protrude from the cover 10 when attached to the cover 10.

Further, the cover 10 is provided with a through hole. The through hole is sealed with a non-magnetic lid 17 made of a non-magnetic material such as resin. As will be described later, the antenna 47 (see FIG. 4) is mounted on the sensor substrate 42.

FIG. 4 is a plan view showing a configuration example of the cover and the coil substrate of the present embodiment. As shown in FIG. 4, a power supply board 41 and a sensor board 42 are attached to the back surface 12a of the top plate 12. The power supply board 41 and the sensor board 42 are located between the side plate 11 and the coil board 20 in a plan view. A power supply unit 43 is mounted on the power supply board 41. The power generation unit is composed of the coil substrate 20 and the magnet 31. The power supply unit 43 converts the single-phase AC power supplied from the power generation unit into a DC voltage and supplies it to the sensor board 42.

A sensor 44, a control unit 45 having a communication circuit, and an antenna 47 are mounted on the sensor board 42. The DC power from the power supply unit 43 is supplied to the sensor 44 and the control unit 45. The sensor 44, the control unit 45, and the antenna 47 may be composed of separate IC (Integrated Circuit) chips, or a part or all of them may be composed of one IC chip. Further, the sensor 44 includes, for example, an acceleration sensor 441, a temperature sensor 442, and an angle sensor 443.

As shown in FIG. 4, the coil substrate 20 has a flexible substrate 21, a coil pattern 23 provided on the flexible substrate 21, and a plurality of yokes 25 provided on the flexible substrate 21. The shape of the flexible substrate 21 in a plan view is a perfect circular ring centered on the axis Ax. The coil pattern 23 has a plurality of flat coils laminated in the thickness direction of the flexible substrate 21. The flat coil is a pattern of a conductor provided in a pattern on a predetermined surface of an insulator. In this embodiment, a conductor pattern is formed on a plurality of surfaces of the insulator. Not limited to this, the pattern of the conductor may be formed on one surface of the insulator.

As shown in FIG. 4, both ends of the coil pattern 23 are connected to the power supply board 41 via the lead wire 16. In this embodiment, the coil pattern 23 and the power supply board 41 may be connected to each other via an FPC (Flexible Printed Circuit) connector instead of the lead wire 16. Alternatively, the coil board 20 may be extended and directly connected to the power supply board 41. Since soldering is not required for the connection using the FPC connector, the productivity of the power generation unit 110 with a sensor can be further increased.

As shown in FIG. 4, the coil pattern 23 has a plurality of first conductive portions 231 and a plurality of second conductive portions 232. The first conductive portion 231 extends in the circumferential direction of a circle centered on the axial center Ax. The second conductive portion 232 extends in the radial direction of the circle centered on the axial center Ax. The first conductive portion 231 and the second conductive portion 232 are alternately connected in series.

The yoke 25 has a first yoke 25A located on one side of the first conductive portion 231 and a second yoke 25B located on the other side of the first conductive portion 231 in a plan view. For example, the first yoke 25A is located on the side farther from the axis Ax than the first conductive portion 231. The second yoke 25B is located closer to the axis Ax than the first conductive portion 231. However, the distance between the first yoke 25A and the axial center Ax and the distance between the second yoke 25B and the axial center Ax are the same length as each other.

For example, the coil pattern 23 is extended so that irregularities are alternately arranged along the circumferential direction of a circle centered on the axis Ax in a plan view. One yoke 25 is arranged in each of the concave and convex recesses 233.

In the present embodiment, the magnet 31 is an encoder magnet in which a magnetic track and a base material are integrated. For example, an encoder magnet is formed by forming a plastic magnet on one surface of a metal base material and alternately magnetizing north and south poles on the surface of the formed plastic magnet.

FIG. 5 is a cross-sectional view of a rotating shaft, a bearing with a sensor, and a housing. FIG. 6 is an enlarged cross-sectional view of a part of FIG. FIG. 7 is an enlarged cross-sectional view of a part of FIG. FIG. 8 is a cross-sectional view of the retainer, magnet and spacer.

The bearing unit 1 according to the present embodiment includes a rotary shaft 70 and a bearing 100 with a sensor (see FIGS. 1 to 3). The bearing 100 with a sensor includes a bearing 120 and a power generation unit 110 with a sensor. Further, the power generation unit 110 with a sensor (power generation unit) is provided between the bearing 120 and the large diameter portion 71. The bearing 120 supports the small diameter portion 72 of the rotating shaft 70.

The rotary shaft 70 can rotate about the axis Ax. The rotary shaft 70 has a large diameter portion 71 and a small diameter portion 72. The small diameter portion 72 has a smaller outer diameter than the large diameter portion 71. Therefore, the outer peripheral surface 72a of the small diameter portion 72 is located radially inside the outer peripheral surface 71a of the large diameter portion 71. A first wall 71b is provided at the boundary between the outer peripheral surface 71a of the large diameter portion 71 and the outer peripheral surface 72a of the small diameter portion 72. The first wall 71b connects the edge of the outer peripheral surface 71a of the large diameter portion 71 on the small diameter portion 72 side and the edge of the outer peripheral surface 72a of the small diameter portion 72 on the large diameter portion 71 side. The first wall 71b is a flat wall extending in the radial direction.

The housing 80 is arranged on the radial outer side of the rotary shaft 70 so as to be separated from the rotary shaft 70. The housing 80 has an inner peripheral surface 80a and a vertical wall surface 80b. The inner peripheral surface 80a extends in the circumferential direction about the axial center Ax. The vertical wall surface 80b extends in the radial direction. The housing 80 is a case (housing) provided in various equipment such as a machine tool.

The bearing 120 has an outer ring 122, an inner ring 121, and a rolling element 123.

The outer ring 122 has an outer peripheral surface 122a, an inner peripheral surface 122b, an outer wall 122c, and an inner side wall 122d. The outer peripheral surface 122a and the inner peripheral surface 122b extend in the circumferential direction about the axial center Ax. The outer side wall 122c and the inner side wall 122d are flat walls extending in the radial direction. A notch 122e is provided at a corner between the outer side wall 122c and the inner peripheral surface 122b. A notch 122f is provided at a corner between the inner side wall 122d and the inner peripheral surface 122b.

The inner ring 121 has an outer peripheral surface 121b (diameter outer end), an inner peripheral surface 121a, an outer wall 121c (second wall), and an inner side wall 121d. As shown in FIG. 7, the corner portion between the inner peripheral surface 121a and the outer wall 121c has the shape of a curved portion 121g curved in an arc shape. The outer peripheral surface 121b and the inner peripheral surface 121a extend in the circumferential direction about the axial center Ax. The outer side wall 121c (second wall) and the inner side wall 121d are flat walls extending in the radial direction. Notches 121e are provided at the corners of the outer side wall 121c and the outer peripheral surface 121b. Notches 121f are provided at the corners of the inner side wall 121d and the outer peripheral surface 121b. The rolling element 123 is provided between the outer ring 122 and the inner ring 121. Further, the outer peripheral end portion of the sealing material 60 is inserted into the notch portion 122e and fixed to the outer ring 122 via an adhesive. The outer peripheral end portion of the sealing material 61 is inserted into the notch portion 122f and fixed to the outer ring 122 via an adhesive.

As described above, the cover 10 has a top plate 12 and a side plate 11. A coil substrate 20 (power generation coil, component) and a circuit board 40 (component) are fixed to the back surface 12a of the top plate 12. Specifically, on the back surface 12a, the coil substrate 20 is located at the end on the inner side in the radial direction, and the circuit board 40 is located on the outer side in the radial direction from the coil substrate 20. Further, as shown in FIGS. 6 and 7, the radial inner end portion of the top plate 12 is a thick portion having a larger plate thickness than the radial outer portion. That is, the back surface 12a of the radial inner end portion protrudes toward the bearing 120 side (right side of FIGS. 6 and 7) with respect to the back surface 12a of the radial outer portion. The coil substrate 20 is fixed to the back surface 12a of the thick portion provided at the inner end in the radial direction. The coil substrate 20 is fixed via, for example, an adhesive. In the present invention, the inner end portion in the radial direction may be a thinner portion than the outer portion in the radial direction. That is, the back surface 12a of the radially inner end portion may be recessed on the opposite side (left side of FIGS. 6 and 7) of the bearing 120 from the back surface 12a of the radially outer portion to form a recess. In this case, the coil substrate 20 is positioned with respect to the top plate 12 by being fitted into the recess, and the back surface 12a of the top plate 12 and the front surface of the coil substrate 20 are substantially flush with each other. Further, as shown in FIGS. 6 and 7, the radial inner end 12b of the cover 10 is located radially inside the outer peripheral surface 71a of the large diameter portion 71. Specifically, the distance between the radial inner end 12b and the outer peripheral surface 71a along the radial direction is the first distance D1. The radial inner edge of the cover 10 at the radial inner end 10a is the radial inner end 12b. The surface 12d of the radial inner end 10a of the cover 10 and the first wall 71b are separated by a fourth distance D4 along the axial direction. The fourth distance D4 is a distance equal to or greater than the amount of axial displacement between the outer ring 122 and the inner ring 121 of the bearing 120 when the rotating shaft 70 rotates. The cover 10 is also referred to as an outer ring spacer.

The outer wall 121c (second wall) of the inner ring 121 is located at a distance from the first wall 71b in the axial direction of the axial center Ax. A retainer 50, a magnet 31, and a spacer 33 are provided between the outer side wall 121c (second wall) and the first wall 71b.

The retainer 50 has a third wall 54, a fourth wall 55, a notched bottom surface 56, a bottom wall 51, a first upper wall 52, and a second upper wall 53. A notch is formed by the fourth wall 55 and the notch bottom surface 56. The second upper wall 53 is located radially outside the first upper wall 52. The third wall 54 is a flat wall extending in the radial direction. The third wall 54 is in contact with the first wall 71b. The bottom wall 51 is in contact with the outer peripheral surface 72a of the small diameter portion 72. The fourth wall 55 is a flat wall extending in the radial direction. The fourth wall 55 is in contact with the thin portion 31b of the magnet 31. The retainer 50 is also referred to as an inner ring spacer.

The magnet 31 has a thin portion 31b on the inner side in the radial direction and a thick portion 31a on the outer side in the radial direction. The radial outer end 31c of the magnet 31 and the radial outer end 20a of the coil substrate 20 are substantially the same in radial position. In other words, the radial outer end 31c and the radial outer end 20a are located side by side in the axial direction. The radial inner end 31d of the magnet 31 is placed on the notched bottom surface 56. The radial outer end 31c of the magnet 31 is located radially outer by a second distance D2 from the outer peripheral surface 121b (diametric outer end) of the inner ring 121.

The spacer 33 has a flat plate shape having a constant axial thickness. The spacer 33 extends in the radial direction. The radial outer end 33a of the spacer 33 is located radially inside the notch 121e. The radial inner end 33b of the spacer 33 is in contact with the notched bottom surface 56. The spacer 33 is in contact with the outer wall 121c (second wall). A thin portion 31b of the magnet 31 is sandwiched between the spacer 33 and the fourth wall 55.

In this way, the retainer 50, the magnet 31, and the spacer 33 are axially sandwiched between the outer wall 121c (second wall) of the inner ring 121 of the bearing 120 and the first wall 71b of the large diameter portion 71 of the rotating shaft 70. Is fixed. The distance along the radial direction between the radial inner end 33b of the spacer 33 and the first upper wall 52 is the third distance D3. The inner side wall 121d of the inner ring 121 of the bearing 120 is fixed in the axial direction by a fixing means (not shown).

Further, as shown in FIG. 5, the side plate 11 of the cover 10 and the outer ring 122 are axially sandwiched between the vertical wall surface 80b of the housing 80 and the fixing member 81. The upper end portion 12c of the surface 12d of the top plate 12 is pressed in the axial direction by the fixing member 81. That is, the outer ring 122 is axially pressed by the vertical wall surface 80b, the fixing member 81, and the side plate 11, and is fixed to the housing 80. As a result, the rolling element 123 rolls, so that the outer ring 122 and the inner ring 121 rotate relatively.

In the present embodiment, since the outer ring 122 and the cover 10 are fixed to the housing 80, the outer ring 122 does not rotate, and the inner ring 121, the retainer 50, the magnet 31 and the spacer 33 rotate integrally with the rotating shaft 70. Further, since the coil substrate 20 and the magnet 31 are arranged so as to face each other in the axial direction, power generation is performed by the relative rotation of the coil substrate 20 and the magnet 31.

As described above, the bearing unit 1 according to the present embodiment includes a rotating shaft 70 having a large diameter portion 71 and a small diameter portion 72, a bearing 120 having an outer ring 122, an inner ring 121, and a rolling element 123, and an outer ring 122. A cover 10 fixed to the above is provided. The radial inner end 12b of the cover 10 is located radially inside the outer peripheral surface 71a of the large diameter portion 71. Further, the power generation unit 110 with a sensor (power generation unit) is provided between the bearing 120 and the large diameter portion 71. The bearing 120 supports the small diameter portion 72 of the rotating shaft 70.

As described above, since the radial inner end 12b of the cover 10 is located radially inside the outer peripheral surface 71a of the large diameter portion 71, the radial length of the cover 10 can be set larger. Therefore, since the size of the cover 10 can be increased, the number of parts mounted on the cover 10 can be increased. It is also possible to mount larger parts on the cover 10.

A magnet 31 is provided on the axial side of the inner ring 121, and the radial outer end 31c of the magnet 31 is located radially outer of the outer peripheral surface 121b (radial outer end) of the inner ring 121. As a result, the length of the magnet 31 in the radial direction can be set to be larger, so that the magnet 31 can be made larger. Therefore, the power generation capacity generated by the coil substrate 20 and the magnet 31 can be further increased.

The large-diameter portion 71 and the small-diameter portion 72 are located adjacent to each other in the axial direction, a first wall 71b is provided at the boundary between the large-diameter portion 71 and the small-diameter portion 72, and the inner ring 121 has an outer wall 121c. (Second wall) is provided. A retainer 50, a spacer 33, and a magnet 31 are provided between the first wall 71b and the outer wall 121c (second wall). Since the magnet 31 rotates together with the rotating shaft 70 and easily shakes in the axial direction during rotation, it is difficult to maintain the degree of orthogonality (orthogonality) with the axial center Ax. Therefore, by flattening the spacer 33 and the fourth wall 55 so as to extend in the radial direction, the accuracy of the degree of orthogonality (orthogonality) between the extending direction of the magnet 31 and the axial center Ax is improved. As a result, when the magnet 31 rotates, the degree of orthogonality between the coil substrate 20 and the magnet 31 is improved, so that the power generation capacity generated by the coil substrate 20 and the magnet 31 can be further increased.

The first wall 71b and the radial inner end portion 10a of the cover 10 are arranged apart from each other in the axial direction. As a result, when the rotating shaft 70 rotates, there is an advantage that the first wall 71b and the cover 10 are less likely to come into contact with each other. The separation distance between the first wall 71b and the radial inner end 10a of the cover 10 is preferably equal to or greater than the amount of axial displacement between the outer ring 122 and the inner ring 121 of the bearing 120 when the rotating shaft 70 rotates.

1 Bearing unit 10 Cover 10a Radial inner end 12b Radial inner end 20 Coil board (power generation coil, parts)
20a Radial outer end 31 Magnet 31c Radial outer end 33 Spacer 40 Circuit board (part)
50 Retainer 54 3rd wall 55 4th wall 70 Rotating shaft 71 Large diameter part 71a Outer peripheral surface 71b 1st wall 72 Small diameter part 72a Outer peripheral surface 80 Housing 110 Power generation unit with sensor (power generation unit)
120 Bearing 121 Inner ring 121b Outer peripheral surface (diameter outer end)
121c outer side wall (second wall)
122 Outer ring 123 Rolling element Ax Axle D1 1st distance D2 2nd distance D3 3rd distance D4 4th distance

Claims (8)

The rotary shaft which is arranged on the inner peripheral side of the housing and has a large diameter portion and a small diameter portion whose outer diameter is smaller than the large diameter portion is located along the axial direction of the axis and is rotatable about the axis. A power generation unit provided between a bearing that supports a small diameter portion and the large diameter portion.
It is provided with a plate-shaped cover that is fixed to the outer ring included in the bearing, extends inward in the radial direction, and is provided with a component including a power generation coil.
The radial inner end of the cover is located radially inside the outer peripheral surface of the large diameter portion.
Power generation unit. A power generation unit further provided with a magnet that faces the power generation coil in the axial direction.
The bearing has an outer ring fixed to the housing, an inner ring fixed to the small diameter portion of the rotating shaft, and a rolling element provided between the outer ring and the inner ring.
The radial outer end of the magnet is located radially outside the radial outer end of the inner ring of the bearing and is axially aligned with the radial outer end of the power generation coil.
The power generation unit according to claim 1. A power generation unit further including a retainer and a spacer that sandwich the magnet.
The large-diameter portion and the small-diameter portion are located adjacent to each other in the axial direction, and a flat first wall extending in the radial direction is provided at a boundary portion between the large-diameter portion and the small-diameter portion, and the inner ring is provided with a flat first wall extending in the radial direction. Is provided with a flat second wall located axially separated from the first wall and extending in the radial direction.
Between the first wall and the second wall
The retainer having a flat third wall extending in the radial direction and in contact with the first wall, and a flat fourth wall extending in the radial direction and located on the opposite side of the third wall in the axial direction.
The flat plate-shaped spacer extending in the radial direction and in contact with the second wall,
The magnet sandwiched between the spacer and the fourth wall is provided.
The power generation unit according to claim 2. The first wall and the radially inner end of the cover are arranged so as to be axially separated from each other.
The power generation unit according to claim 3. A rotating shaft that is rotatable about the axis and has a large diameter portion and a small diameter portion whose outer diameter is smaller than that of the large diameter portion is located along the axial direction of the axis.
It has an outer ring fixed to a housing located on the radial outer side of the rotating shaft, an inner ring fixed to the small diameter portion of the rotating shaft, and a rolling element provided between the outer ring and the inner ring. Bearings and
A plate-shaped cover that is fixed to the outer ring, extends inward in the radial direction, and is provided with parts.
With
The radial inner end of the cover is located radially inside the outer peripheral surface of the large diameter portion.
Bearing unit. The component includes a power generation coil
A magnet extending in the radial direction and facing the power generating coil in the axial direction is provided on the axial side of the inner ring, and the radial outer end of the magnet is from the radial outer end of the inner ring of the bearing. Is located on the outer side in the radial direction and is aligned axially with the outer end in the radial direction of the power generation coil.
The bearing unit according to claim 5. The large-diameter portion and the small-diameter portion are located adjacent to each other in the axial direction, and a flat first wall extending in the radial direction is provided at a boundary portion between the large-diameter portion and the small-diameter portion, and the inner ring is provided with a flat first wall extending in the radial direction. Is provided with a flat second wall located axially separated from the first wall and extending in the radial direction.
Between the first wall and the second wall
A retainer having a flat third wall extending in the radial direction and in contact with the first wall, and a flat fourth wall extending in the radial direction and located on the opposite side of the third wall in the axial direction.
A flat spacer extending in the radial direction and in contact with the second wall,
The magnet sandwiched between the spacer and the fourth wall is provided.
The bearing unit according to claim 6. The first wall and the radially inner end of the cover are arranged so as to be axially separated from each other.
The bearing unit according to claim 7.

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