Rotary connector

Abstract

To provide a rotary connector which can generate abrasion powder.SOLUTION: A rotary connector 1 includes: an annular conductive ring 30; a conductive shaft 20 inserted through the conductive ring 30 and arranged to be relatively rotatable with respect to the conductive ring 30; and a current collector 4 disposed in contact between the conductive ring 30 and the conductive shaft 20 in a radial direction. The current collector 4 is pressed against a bulging portion 28 that protrudes in the radial direction and is provided on at least one of the conductive ring 30 and the conductive shaft 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rotary connector, for example, a rotary connector for electrically connecting a rotating element and a stationary element in a rotating mechanism. [Background technology]

[0002] Rotary connectors are known in various industrial fields for electrically connecting a rotating element and a stationary element in a rotating mechanism, and are capable of electrically connecting the conductive ring and the conductive shaft through a current collecting element disposed between the conductive ring and the conductive shaft.

[0003] Known types of rotary connectors include those filled with liquid metal such as mercury or a gallium alloy as the current collecting element, and those with multiple conductive roller current collectors. In recent years, rotary connectors using roller current collectors have been attracting attention due to the environmental impact caused by liquid leakage and the risk of electric leakage.

[0004] For example, the rotary connector disclosed in Patent Document 1 includes an annular outer peripheral member, a shaft, and a roller current collector. The shaft has a narrowed portion formed thereon. The roller current collector is disposed in the narrowed portion. The roller current collector is disposed radially between the outer peripheral member and the shaft, and is in contact with both. The roller current collector performs so-called planetary motion, revolving while rotating on its own axis, in response to the rotation of the shaft relative to the outer peripheral member. This allows the shaft and the outer peripheral member to be electrically connected even when the shaft rotates relative to the outer peripheral member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-218997 A (page 3, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0006] In the rotary connector of Patent Document 1, the axial position of the roller current collector arranged in the small diameter portion of the shaft is maintained by the large diameter portion that is axially outward of the small diameter portion.

[0007] However, when the roller current collector tilts relative to the axis of the shaft, its axial end portion comes into contact with the shaft or the outer peripheral member, which can cause stress concentration at the axial end portion, known as edge load.When edge load occurs, there is a risk that part of the shaft or the outer peripheral member will be scraped off, generating wear powder.

[0008] The present invention has been made in light of these problems, and has an object to provide a rotary connector that can suppress the generation of wear powder. [Means for solving the problem]

[0009] In order to solve the above problems, the rotary connector of the present invention comprises: A rotary connector comprising: an annular conductive ring; a conductive shaft inserted into the conductive ring and arranged rotatable relative to the conductive ring; and a current collector arranged in contact with the conductive ring and the conductive shaft in a radial direction, The current collector is pressed against a bulging portion that bulges out in the radial direction and is provided on at least one of the conductive ring and the conductive shaft. This creates a so-called centering effect during rotation, which acts on the current collector to move it in the bulging direction, positioning the current collector and preventing it from moving wildly. This makes it less likely for the current collector to come into uneven contact with the conductive ring or conductive shaft during rotation, thereby suppressing the generation of wear powder.

[0010] The bulge may be provided on the conductive shaft. This reduces the force with which the bulging portion presses the current collector due to the centrifugal force acting on the current collector, thereby suppressing the generation of wear powder. Also, the bulging shape can be easily formed.

[0011] The current collector may be more elastically deformable than the conductive shaft. This allows the current collector to be positioned with a simple configuration and made less likely to move wildly.

[0012] The bulging portion may bulge at the center of a contact portion with the current collector. This allows the current collector to be held at the center of the contact portion in the bulging portion.

[0013] The bulging portion may be formed by a curved surface. This prevents plastic deformation of the current collector, making it possible to stably hold the current collector. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view showing a rotary connector according to a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. 1. [Figure 3] 2A and 2B are diagrams for explaining the main parts of the rotary connector in the first embodiment. [Figure 4] 10A and 10B are diagrams illustrating a main part of a rotary connector according to a second embodiment of the present invention. [Figure 5] 10A and 10B are diagrams illustrating a main part of a rotary connector according to a third embodiment of the present invention. [Figure 6] 10A and 10B are diagrams illustrating the main parts of a rotary connector according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary connector according to an embodiment of the present invention will be described below with reference to the accompanying drawings. [Example]

[0016] A rotary connector according to a first embodiment will be described with reference to Figures 1 to 3. In the following description, the top and bottom of the rotary connector are defined as the top and bottom when viewed from the front in Figure 1.

[0017] The rotary connector 1 of this embodiment is placed vertically and is used, for example, at a rotating point in a rotating mechanism. The rotary connector 1 passes electricity supplied from an external power source to a rotating shaft in the rotating mechanism.

[0018] 1, the rotary connector 1 is mainly composed of a rotating element 2, a stationary element 3, seven roller current collectors 4, and seven rotary spacers 5. In this embodiment, the roller current collectors 4 and rotary spacers 5 are evenly spaced in the circumferential direction, but the number and arrangement of these may be changed as appropriate.

[0019] The rotating element 2 includes a conductive shaft 20 , a lower bearing 40 , and an upper bearing 41 .

[0020] The conductive shaft 20 is connected to a rotation shaft (not shown) of the rotation mechanism. The conductive shaft 20 is provided so as to be rotatable relative to the stationary element 3 by being rotated by the rotation shaft.

[0021] The conductive shaft 20 is made of a highly conductive material and has a stepped cylindrical shape. The conductive shaft 20 has a large diameter body portion 23, a lower small diameter body portion 24, and an upper small diameter body portion 25. The conductive shaft 20 may be hollow.

[0022] The outer peripheral surface 28a of the large-diameter body portion 23 is plated with a highly conductive material such as silver. Note that the plating is not shown in the drawings because it is thin and would make the drawing too complicated. The same applies to plating in the following description.

[0023] The lower small diameter body portion 24 has a stepped cylindrical shape and extends axially downward from the center of the lower end face of the large diameter body portion 23. The lower small diameter body portion 24 has a smaller diameter than the large diameter body portion 23.

[0024] The upper small diameter body portion 25 has a stepped cylindrical shape on the outer diameter side, and extends axially upward from the center of the upper end face of the large diameter body portion 23. The upper small diameter body portion 25 has a smaller diameter than the large diameter body portion 23.

[0025] The stationary element 3 can be connected to an external power source (not shown) and is mainly composed of a conductive ring 30, a lower guide plate 31, an upper guide plate 32, a housing 35, and a cover 36.

[0026] The conductive ring 30 is cylindrically formed from a highly conductive material. The inner peripheral surface 30a of the conductive ring 30 is plated with a highly conductive material such as silver. Inside the conductive ring 30, the large-diameter body portion 23 of the conductive shaft 20 of the rotating element 2, the roller current collectors 4, and the rotary spacers 5 are arranged.

[0027] The lower guide plate 31 is formed in a cylindrical shape and is disposed below the conductive ring 30 .

[0028] A lower recess 31a and an upper recess 31b are formed in the radial center of the lower guide plate 31. The lower recess 31a and the upper recess 31b are separated in the axial direction by an annular flange 31c that protrudes inward.

[0029] Specifically, the lower recess 31a is recessed axially upward from the lower end face of the lower guide plate 31 and is open axially downward. The upper recess 31b is recessed axially downward from the upper end face of the lower guide plate 31 and is open axially upward. The flange 31c protrudes radially inward from the upper end of the inner circumferential surface of the lower recess 31a.

[0030] A lower bearing 40 is inserted into the lower recess 31a. The lower bearing 40 abuts against the flange 31c in the axial direction.

[0031] The lower bearing 40 is made of a porous resin material and is formed in an annular shape. The lower bearing 40 is impregnated with oil as a lubricant. The same is true for the upper bearing 41.

[0032] The lower small diameter body portion 24 of the conductive shaft 20 of the rotating element 2 is inserted into the lower guide plate 31. The lower small diameter body portion 24 penetrates the flange 31c from the upper recess 31b side and is fitted into the lower bearing 40.

[0033] Furthermore, the step portion of the lower small diameter body portion 24 abuts against the lower bearing 40 in the axial direction.

[0034] The lower end of the rotating spacer 5 is placed in contact with the upper recess 31b on the outer diameter side of a flange portion 27 of the large diameter body portion 23, which will be described later, and is able to roll on the rotating spacer 5. The outer peripheral side surface of the upper recess 31b is placed on the inner diameter side of the inner peripheral surface 30a of the conductive ring 30, and the rotating spacer 5 can guide the rolling of the conductive ring 30 without contacting the conductive ring 30.

[0035] The upper guide plate 32 is formed in a cylindrical shape and is disposed above the conductive ring 30. The upper guide plate 32 has a through hole 32a formed in the radial center thereof, which passes through in the axial direction. The lower end of the through hole 32a forms a recess 32b whose diameter is expanded toward the outer diameter side.

[0036] An upper bearing 41 is inserted into the through hole 32a.

[0037] The upper small diameter body portion 25 of the conductive shaft 20 of the rotating element 2 is inserted into the upper guide plate 32. The upper small diameter body portion 25 is fitted into the upper bearing 41 through the through hole 32a from the recess 32b side.

[0038] Additionally, the step in the upper small diameter body portion 25 abuts against the upper bearing 41 in the axial direction. In other words, the step in the lower small diameter body portion 24 and the step in the upper small diameter body portion 25 function as a spacer, maintaining the axial position of the conductive shaft 20.

[0039] The upper end of the rotation spacer 5 is placed in contact with the recess 32b, allowing the rotation spacer 5 to roll. The outer circumferential side surface of the recess 32b has approximately the same diameter as the outer circumferential side surface of the upper recess 31b in the lower guide plate 31, allowing the rotation spacer 5 to be guided in its rolling motion.

[0040] The housing 35 is formed in a cross section in an upside-down U-shape, and the cover 36 is formed in a thin plate shape.

[0041] The conductive ring 30, the lower guide plate 31, and the upper guide plate 32 are fitted inside the housing 35. A cover 36 is fixed to the lower end of the cylindrical portion of the housing 35 by bolts.

[0042] The roller current collector 4 is made of a highly conductive metal, such as copper or a copper alloy, and is formed into a cylindrical shape (see FIGS. 2 and 3) that extends linearly in the axial direction. Its outer circumferential surface is plated with a highly conductive material, such as silver. After assembly, the roller current collector 4 is elastically deformed at the point where it abuts against the central portion 28c of the conductive shaft 20, as shown by the solid line in FIG. 3. For reference, the shape of the elastically deformed point before assembly is also shown by the two-dot chain line in FIG. 3.

[0043] The roller current collector 4 is formed to be elastically deformable. More specifically, the roller current collector 4 is more elastically deformable than the conductive shaft 20 and the conductive ring 30.

[0044] The roller current collector 4 is disposed axially between the lower guide plate 31 and the upper guide plate 32. The roller current collector 4 is disposed radially between the large diameter body portion 23 of the conductive shaft 20 and the conductive ring 30 in a state of being compressed in the radial direction. This allows the roller current collector 4 to be maintained in contact with the conductive shaft 20 and the conductive ring 30.

[0045] The roller current collector 4 is in contact with the large diameter body 23 and the conductive ring 30 in a dry state, i.e., without any lubricant present, thereby keeping stable the electrical resistance between the conductive shaft 20 and the roller current collector 4 and the electrical resistance between the roller current collector 4 and the conductive ring 30.

[0046] The rotating spacer 5 is made of an insulating resin material and has a cylindrical shape. The rotating spacer 5 is longer in the axial direction than the roller current collector 4, and has a smaller diameter than the roller current collector 4.

[0047] As shown in FIG. 2, the rotation spacer 5 is disposed such that its central axis A1 is radially outer than the central axis A2 of the roller current collector 4 and between adjacent roller current collectors 4 in the circumferential direction.

[0048] When the rotation shaft of the rotation mechanism rotates, the conductive shaft 20 also rotates accordingly. In response to the rotation of the conductive shaft 20, each roller current collector 4 rotates in the opposite direction to the rotation direction of the conductive shaft 20 while revolving in the rotation direction of the conductive shaft 20 (see the thick black arrows).

[0049] Each rotation spacer 5 rotates in the opposite direction to the rotation of the roller current collector 4 as the roller current collector 4 rotates, while revolving in the same direction as the revolution of the roller current collector 4 (see the bold arrow).

[0050] Circumferentially adjacent roller current collectors 4 are prevented from contacting each other by the rotation spacers 5 arranged between them in the circumferential direction. In other words, the rotation spacers 5 maintain the circumferential distance between the adjacent roller current collectors 4.

[0051] The rotational spacer may be arranged so that its central axis is radially inward relative to the central axis of the roller current collector, or may be arranged radially inward and radially outward relative to the central axis of the roller current collector. Furthermore, multiple rotational spacers may be arranged circumferentially between adjacent roller current collectors. Furthermore, the rotational spacer may be rotatably supported by an annular member that is inserted around the conductive shaft and rotatable around the conductive shaft. In other words, the number, arrangement, and configuration of the rotational spacers may be changed as appropriate, as long as the circumferential spacing between adjacent roller current collectors can be maintained.

[0052] In other words, the rotary connector 1 of this embodiment can omit the core material that pivotally supports each roller current collector 4. This makes it easier to elastically deform the roller current collector 4. The roller current collector 4 may also be pivotally supported by a core material.

[0053] The rotary connector 1 of this embodiment is less likely to generate wear particles, which will be explained in detail below.

[0054] As shown in FIGS. 1 and 3, the large diameter body portion 23 of the conductive shaft 20 has flange portions 27 provided at both axial ends and a bulge portion 28 formed in the axial center.

[0055] The flange portion 27 is in the shape of a disk that projects radially outward from the upper end or the lower end of the bulging portion 28. The flange portion 27 has a larger diameter than the bulging portion 28.

[0056] The bulging portion 28 has a barrel shape in which the diameter decreases from the axial center 28b, which is the outermost portion of the outer peripheral surface 28a, toward the upper or lower axial end. That is, the outer peripheral surface 28a of the bulging portion 28 has its axial center 28b as its apex, and curves inward toward both axial ends. In other words, the bulging portion 28 is defined and configured by the curved outer peripheral surface 28a. The outer peripheral surface 28a is smoothly continuous without bending in the axial and circumferential directions. In this embodiment, this curved surface has a shape with one curvature, but it may have two or more curvatures.

[0057] In the following description, the axial center 28b of the outer peripheral surface 28a of the bulging portion 28 will be simply referred to as the "axial center 28b of the bulging portion 28." The same applies to the central portion 28c of the outer peripheral surface 28a of the bulging portion 28, which will be described later, and will be simply referred to as the "central portion 28c of the bulging portion 28."

[0058] As shown in FIG. 3, the roller current collector 4 is disposed so that its axial center and the axial center 28b of the bulging portion 28 substantially coincide with each other in the radial direction.

[0059] The axial center portion of the roller current collector 4 is pressed toward the outer diameter side, i.e., toward the conductive ring 30, by the center portion 28c of the bulging portion 28. As a result, the roller current collector 4 is pressed against the inner circumferential surface 30a of the conductive ring 30, which extends linearly in the axial direction. Note that the center portion 28c is the portion that mainly comes into contact with the roller current collector 4 in this embodiment.

[0060] Furthermore, the roller current collector 4 is elastically deformed at the contact portion with the central portion 28c of the bulging portion 28 so as to conform to the shape of the central portion 28c. The roller current collector 4 is also elastically deformed in the axial direction outside the contact portion with the central portion 28c. In other words, in the cross section of the roller current collector 4 taken in the diameter direction as shown in Figure 3, the shape of the inner diameter side and the shape of the outer diameter side with respect to its own axis are asymmetric. Note that for convenience of explanation, the elastic deformation of the roller current collector 4 is exaggerated in Figure 3.

[0061] Specifically, the roller current collector 4 is most elastically deformed at the contact point with the axial center 28b of the bulging portion 28, and the elastic deformation decreases toward the axially outer side from this point.

[0062] In other words, the elastic force generated by the roller current collector 4 is greatest at the point where it contacts the axial center 28b, and the elastic force decreases toward the axial side from this point. Note that the part of the roller current collector 4 that has elastically deformed due to contact with the bulge 28 elastically returns to a straight shape when it is sufficiently separated from the bulge 28 in the circumferential direction.

[0063] When the conductive shaft 20 rotates, if the roller current collector 4 moves axially upward relative to the bulge portion 28, the elastic force generated axially below the axial center 28b becomes greater than the elastic force generated axially above the axial center 28b.

[0064] The elastic force generated axially below the axial center 28b is the resultant force of a radially inward force in the conductive shaft 20 and a downward axial force. This elastic force causes the roller current collector 4 to move axially downward. In other words, the rotary connector 1 achieves a so-called centering effect, in which the axial position of the roller current collector 4 is adjusted. This is because, even when the roller current collector 4 tries to move axially downward relative to the bulge 28, an upward axial force is also applied to the roller current collector 4.

[0065] Furthermore, when the conductive shaft 20 rotates, if the upper side of the axis of the roller current collector 4 tilts relative to the axis of the bulge 28 so as to approach the bulge 28, the elastic force generated axially above the axial center 28b becomes greater than the elastic force generated axially below the axial center 28b.

[0066] The elastic force generated axially above the axial center 28b is the resultant force of the radially inward force and the axially upward force in the conductive shaft 20. This elastic force returns the tilt of the axis of the roller current collector 4 to be parallel with the axis of the bulge 28. This also applies when the roller current collector 4 is tilted with respect to the axis of the bulge 28 so that the lower side of the axis of the roller current collector 4 approaches the bulge 28.

[0067] The roller current collector 4 has its axial center in contact with the central portion 28c of the bulging portion 28, and the portion axially outward from this contacting portion is spaced apart toward the outer diameter without contacting the outer peripheral surface 28a of the bulging portion 28. As described above, since the outer peripheral surface 28a is a curved surface, the distance between the roller current collector 4 and the outer peripheral surface 28a increases as it moves axially outward.

[0068] This makes it difficult for the edge of the roller current collector 4 to come into contact with the outer circumferential surface 28a even if the axis of the roller current collector 4 tilts with respect to the axis of the conductive shaft 20. In other words, the roller current collector 4 is unlikely to come into uneven contact with the conductive shaft 20.

[0069] Furthermore, even if the axis of the roller current collector 4 tilts relative to the axis of the conductive shaft 20 and the part that was previously in a non-contact state comes into contact with the outer peripheral surface 28a, the force generated at the time of contact is easily reduced because the outer peripheral surface 28a is a curved surface.

[0070] The flange portion 27 has an inclined surface 27a that slopes from the lower end of its outer circumferential surface toward the inner diameter side and extends axially downward. The inclined surface 27a is inclined toward the inner diameter side at approximately 60 degrees from the outer circumferential surface of the flange portion 27.

[0071] Even if the roller current collector 4 moves in the axial direction relative to the conductive shaft 20 and comes into contact with the inclined surface 27a, the axial end portion elastically deforms toward the outer diameter side and the axial center side, and the resulting elastic force moves the roller current collector 4 toward the axial center side.

[0072] From this viewpoint, the inclination angle of inclined surface 27a relative to the outer peripheral surface of flange portion 27 is preferably in the range of more than 0 degrees and less than 90 degrees, and more preferably in the range of about 10 degrees to 60 degrees.

[0073] As described above, in the rotary connector 1 of this embodiment, due to the centering effect that occurs when rotating, a force acts to move the axial upper and other sides of the roller current collector 4 toward the axial center 28b of the bulge portion 28.

[0074] This centering effect positions the roller current collector 4, more specifically, prevents it from moving axially or tilting, making it less likely to move around. This makes it less likely for the roller current collector 4 to come into uneven contact with the conductive ring 30 or the conductive shaft 20 during rotation. This makes it possible to suppress the generation of wear powder.

[0075] Furthermore, centrifugal force acts on the roller current collector 4 due to the planetary motion. Since the bulge 28 is formed on the conductive shaft 20 arranged on the inner diameter side, the force with which the bulge 28 presses the roller current collector 4 due to the centrifugal force acting on the roller current collector 4 can be reduced. This makes it possible to suppress the generation of wear powder.

[0076] Furthermore, compared to the case where the conductive ring 330 is provided with the bulging portion 328 as in the fourth embodiment described later, the force with which the roller current collector 4, to which centrifugal force acts, is pressed by the conductive ring 30 can be reduced.

[0077] Furthermore, since the bulge 28 is formed on the conductive shaft 20, it can be easily formed.

[0078] Furthermore, the roller current collector 4 is formed to be more easily elastically deformable than the conductive shaft 20. This allows a centering effect to be generated with a simple configuration, and the roller current collector 4 can be positioned to prevent it from moving wildly.

[0079] Furthermore, the roller current collector 4 is hollow, and the conductive shaft 20 is solid. These features allow the roller current collector 4 to be more easily elastically deformable than the conductive shaft 20 with a simple configuration.

[0080] Furthermore, the bulging portion 28 has a bulging central portion 28c which is a contact portion with the roller current collector 4, and therefore the roller current collector 4 can be held at the central portion 28c.

[0081] Furthermore, since the bulging portion 28 is configured with the outer peripheral surface 28a that is a curved surface, plastic deformation of the roller current collector 4 can be prevented, and the roller current collector 4 can be stably held. [Example]

[0082] Next, a rotary connector according to a second embodiment will be described with reference to Fig. 4. Note that a description of the same configuration as in the first embodiment will be omitted.

[0083] 4, the large-diameter body portion 123 of the conductive shaft 120 of this embodiment has a cylindrical step portion 127 that extends axially outward from the upper end or the lower end of the bulging portion 28. Even with this configuration, the roller current collector 4 is positioned by the centering effect.

[0084] That is, the conductive shaft 220 of this embodiment can omit the flange portion 27 of the first embodiment. This reduces the undulations in the conductive shaft 220, making it possible to prevent dispersion of high-frequency current. That is, the conductive shaft 220 can have better electrical conductivity. Furthermore, the manufacturing cost of the conductive shaft 220 can be reduced.

[0085] Furthermore, by omitting the flange portion 27 in the first embodiment, the roller current collector 4 is prevented from coming into contact with the flange portion 27 even when it moves in the axial direction, and therefore the generation of wear powder can be suppressed. [Example]

[0086] Next, a rotary connector according to a third embodiment will be described with reference to Fig. 5. Note that a description of the same configuration as in the first embodiment will be omitted.

[0087] 5, the large diameter body portion 223 of the conductive shaft 220 of this embodiment has only a bulging portion 228. Even with this configuration, the roller current collector 4 is positioned by the centering effect.

[0088] That is, the conductive shaft 220 of this embodiment does not have the flange portion 27 in the first embodiment or the step portion 127 in the second embodiment, thereby improving electrical conductivity and reducing manufacturing costs.

[0089] Furthermore, by omitting the flange portion 27 in the first embodiment and the step portion 127 in the second embodiment, the conductive shaft 220 in this embodiment is prevented from contacting the outer peripheral surfaces of the flange portion 27 and the step portion 127 even when the roller current collector 4 moves in the axial direction, thereby suppressing the generation of wear powder.

[0090] Furthermore, the conductive shaft 220 of this embodiment can be made shorter in axial dimension by omitting the flange portion 27 in the first embodiment and the step portion 127 in the second embodiment. [Example]

[0091] Next, a rotary connector according to a fourth embodiment will be described with reference to Fig. 6. Note that a description of the same configuration as in the first embodiment will be omitted.

[0092] As shown in Figure 6, the rotary connector 301 of this embodiment has a flange portion 327 and a bulge portion 328 provided on a conductive ring 330. The flange portion 327 protrudes toward the inner diameter side. The bulge portion 328 has a curved inner circumferential surface 328a with an apex protruding toward the inner diameter side. On the other hand, the conductive shaft 320 does not have the flange portion or bulge portion as in the first embodiment. Even with this configuration, the roller current collector 4 is positioned by the centering effect.

[0093] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0094] For example, in the first to fourth embodiments, the rotary connector is vertically oriented, but the present invention is not limited to this, and the rotary connector may be horizontally oriented.

[0095] Furthermore, in the above-described Examples 1 to 4, a configuration was described in which the conductive shaft is the rotating element and the conductive ring is the stationary element, but this is not limited to this, and the conductive shaft may be the stationary element and the conductive ring may be the rotating element.

[0096] Furthermore, in the first to fourth embodiments, the current collector is a roller current collector, but the present invention is not limited to this and may be an annular current collector or may be modified as appropriate.

[0097] Furthermore, in the first to fourth embodiments, the current collector is described as being cylindrical, but the present invention is not limited to this and may be solid as long as it is elastically deformable.

[0098] Furthermore, in the first to fourth embodiments, the current collector was elastically deformable along the axial direction, but this is not limiting, and only the portion in contact with the bulging portion may be elastically deformable.

[0099] In addition, in Examples 1 to 4, the current collector is described as having a cylindrical shape extending linearly in the axial direction, but this is not limited thereto, and the side surface of the current collector may be a curved surface that curves toward the outer diameter side or the inner diameter side. In such a configuration, it is preferable that the curvature of the side surface of the current collector is smaller than the curvature of the bulging portion.

[0100] Furthermore, in Examples 1 to 4, the bulging portion was described as being formed by a curved surface, but this is not limited to this and may be formed by a polygonal surface, at least a portion of the bulging portion may be linear, and the shape may be changed as appropriate as long as it bulges toward the current collector side. [Explanation of symbols]

[0101] 1 rotary connector 2 Rotating element 3 Stationary element 4 Roller collector 5 Rotation spacer 20 Conductive shaft 28 Bulge 28b central part 30 Conductive ring 120 Conductive shaft 220 Conductive shaft 301 rotary connector 320 Conductive Shaft 328 Bulge 330 Conductive Ring

Claims

1. A rotary connector comprising: an annular conductive ring; a conductive shaft inserted into the conductive ring and arranged rotatable relative to the conductive ring; and a current collector arranged in contact with the conductive ring and the conductive shaft in a radial direction, The current collector is pressed against a radially expanding portion provided on at least one of the conductive ring and the conductive shaft.

2. 2. The rotary connector according to claim 1, wherein the bulge is provided on the conductive shaft.

3. 2. The rotary connector according to claim 1, wherein the current collector is more elastically deformable than the conductive shaft.

4. 2. The rotary connector according to claim 1, wherein the bulging portion bulges out at the center of a contact portion with the current collector.

5. 5. The rotary connector according to claim 1, wherein the bulging portion is formed by a curved surface.

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