Rotary connector

Abstract

The present invention provides a rotary connector capable of suppressing generation of abrasion powder.　A rotary connector 1 comprises: an annular conductive ring 30; a conductive shaft 20 inserted into the conductive ring 30 and disposed so as to be relatively rotatable with the conductive ring 30; and a current collector 4 disposed between the conductive ring 30 and the conductive shaft 20 in the radial direction. At least one of the conductive ring 30 and the conductive shaft 20 has a groove 28 formed at a position on an axial-direction end 4a of the current collector 4.

Description

rotary connector

[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.

[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.

[0005] JP 2013-218997 A (page 3, Figure 1)

[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.

[0009] In order to solve the above problems, the rotary connector of the present invention is 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 radially between the conductive ring and the conductive shaft, wherein a groove is formed in at least one of the conductive ring and the conductive shaft at the position of the axial end of the current collector. The groove reduces the frequency and force of partial contact of the axial end of the current collector with the conductive ring or the conductive shaft. This makes it possible to suppress the generation of wear powder. Additionally, the wear powder can be accumulated in the groove.

[0010] The grooves may be formed at both axial end positions of the current collector, thereby reducing the frequency of and force generated when both axial end positions of the current collector come into partial contact with the conductive ring or the conductive shaft.

[0011] The groove may be formed in the conductive shaft, which allows the groove to be formed easily.

[0012] The groove may be formed in the conductive ring, whereby the groove has a large volume and is therefore likely to accumulate wear particles.

[0013] A flange may be formed axially outward from the groove, whereby the flange formed axially outward from the groove can maintain the position of the current collector so that the axial end of the current collector is positioned in the groove.

[0014] The groove may extend in the circumferential direction, which more reliably reduces the frequency of partial contact of the axial end of the current collector with the conductive ring or the conductive shaft, and the force generated thereby.

[0015] FIG. 1 is a cross-sectional view showing a rotary connector in a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1. FIG. 3 is a diagram illustrating a main part of the rotary connector in the first embodiment. FIG. 4 is a diagram illustrating a main part of a conductive shaft in a second embodiment of the present invention. FIG. 5 is a diagram illustrating a main part of a rotary connector in a third embodiment of the present invention. FIG. 6 is a diagram illustrating a main part of a conductive shaft in a fourth embodiment of the present invention. FIG. 7 is a cross-sectional view showing a main part of a rotary connector in a fifth embodiment of the present invention. FIG. 8 is a cross-sectional view showing a rotary connector in a sixth embodiment of the present invention.

[0016] 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.

[0017] 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 of Figure 1.

[0018] The rotary connector 1 of this embodiment is placed vertically and is used, for example, at a rotating portion of a rotating mechanism. The rotary connector 1 passes electricity supplied from an external power source to a rotating shaft of the rotating mechanism.

[0019] 1 and 2, 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.

[0020] The rotating element 2 includes a conductive shaft 20 , a lower slinger 21 , an upper slinger 22 , a lower bearing 40 , and an upper bearing 41 .

[0021] 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.

[0022] 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.

[0023] The outer peripheral surface 23a 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 figure because it is thin and would make the drawing too complicated. The same applies to plating in the following description.

[0024] The lower small diameter body portion 24 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. The lower slinger 21 is fitted onto the lower small diameter body portion 24.

[0025] The lower slinger 21 is formed in an annular shape from a non-conductive material. The lower slinger 21 has a cylindrical rim portion 21a extending in the axial direction and a flange portion 21b that projects radially outward from the upper end of the rim portion 21a. A lower small-diameter body portion 24 of the lower slinger 21 is press-fitted and fixed to the rim portion 21a. The lower slinger 21 also abuts against the large-diameter body portion 23 in the axial direction.

[0026] The upper small diameter body portion 25 is cylindrical 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. The upper slinger 22 is fitted onto the upper small diameter body portion 25.

[0027] The upper slinger 22 is formed in an annular shape from a non-conductive material. The upper slinger 22 has a cylindrical inner rim portion 22a extending in the axial direction, a bottom portion 22b that projects radially outward from the lower end of the inner rim portion 22a, and an outer rim portion 22c that extends axially upward from the outer end of the bottom portion 22b. An upper small-diameter body portion 25 is press-fitted and fixed into the inner rim portion 22a of the upper slinger 22. The upper slinger 22 also abuts against the large-diameter body portion 23 in the axial direction.

[0028] The gap between the upper slinger 22 and the upper small diameter body portion 25 is sealed by an O-ring 26. The O-ring 26 is disposed in an annular groove that is recessed radially inward from the outer circumferential surface of the upper small diameter body portion 25 and is open toward the outer diameter side. Note that the annular groove in which the O-ring is disposed may be provided in the upper slinger 22.

[0029] 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.

[0030] The conductive ring 30 is cylindrical and made of 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 rotation spacers 5 are arranged.

[0031] The lower guide plate 31 is formed in a cylindrical shape and is disposed below the conductive ring 30 .

[0032] A lower recess 31 a and an upper recess 31 b are formed in the radial center of the lower guide plate 31. The lower recess 31 a and the upper recess 31 b are separated in the axial direction by an annular flange 31 c that protrudes inward.

[0033] 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 and toward the inner diameter side. The upper recess 31b is recessed axially downward from the upper end face of the lower guide plate 31 and is open axially upward and toward the inner diameter side. The flange 31c protrudes toward the inner diameter side from the upper end of the inner circumferential surface of the lower recess 31a.

[0034] A lower bearing 40 is inserted into the lower recess 31a. The lower bearing 40 abuts against the flange 31c in the axial direction.

[0035] 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.

[0036] 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 passes through a through-hole on the inside of the flange 31c from the upper recess 31b side and is fitted into the lower bearing 40.

[0037] The lower slinger 21, which is fixed to the lower small-diameter body portion 24, is disposed on the inner diameter side of the lower guide plate 31. The rim portion 21a of the lower slinger 21 passes through a through-hole on the inside of the flange 31c from the upper recess 31b side and abuts against the lower bearing 40. The flange portion 21b of the lower slinger 21 protrudes outward beyond the through-hole on the inside of the flange 31c, and a portion of it faces the flange 31c in the axial direction.

[0038] The lower slinger 21 rotates integrally with the conductive shaft 20 .

[0039] The lower end of the rotating spacer 5 is disposed in contact with the upper recess 31b on the outer diameter side of the flange portion 21b of the lower slinger 21, allowing the rotating spacer 5 to roll. The outer peripheral side surface of the upper recess 31b is disposed on the inner diameter side of the inner peripheral surface 30a of the conductive ring 30, allowing the rotating spacer 5 to roll without contacting the conductive ring 30.

[0040] 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 that passes through the center in the radial direction in the axial direction. The lower end of the through hole 32a forms a recess 32b that expands in diameter toward the outer diameter side.

[0041] An upper bearing 41 is inserted into the through hole 32a.

[0042] 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 an upper bearing 41 inserted into the through hole 32a from the recess 32b side.

[0043] Additionally, the upper slinger 22 fixed to the upper small-diameter body portion 25 is disposed within the through-hole 32a. The inner rim portion 22a of the upper slinger 22 abuts against the upper bearing 41 in the axial direction. In other words, the lower slinger 21 and the upper slinger 22 function as a spacer, maintaining the axial position of the conductive shaft 20.

[0044] The upper slinger 22 rotates integrally with the conductive shaft 20 .

[0045] 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 surface of the recess 32b has approximately the same diameter as the outer circumferential surface of the upper recess 31b of the lower guide plate 31, allowing the rotation spacer 5 to be guided in its rolling motion.

[0046] The housing 35 has a cross section in the shape of an upside-down U. The cover 36 is formed in the shape of a thin plate.

[0047] 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.

[0048] The roller current collector 4 is made of a highly conductive metal, such as copper or a copper alloy, and is formed into an elastically deformable cylindrical shape. The outer circumferential surface of the roller current collector 4 is plated with a highly conductive material, such as silver.

[0049] 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 compressed between the large diameter body portion 23 of the conductive shaft 20 and the conductive ring 30. This allows the roller current collector 4 to be maintained in contact with the conductive shaft 20 and the conductive ring 30.

[0050] 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. This keeps 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 stable. The lower slinger 21 and the upper slinger 22 also keep the roller current collector 4 in a dry state.

[0051] 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.

[0052] As shown in Fig. 2, the central axis A1 of the rotating spacer 5 is located radially outward of the central axis A2 of the roller current collector 4 and is disposed circumferentially between adjacent roller current collectors 4. Note that in Fig. 2, the lower slinger 21 is not shown in order to clearly show that the rotating spacer 5 is located within the upper recess 31b of the lower guide plate 31.

[0053] 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 arrow).

[0054] 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 around its axis, while revolving in the same direction as the revolution of the roller current collector 4 (see the bold arrow).

[0055] The roller current collectors 4 adjacent in the circumferential direction are prevented from contacting each other by the rotation spacers 5 disposed between them in the circumferential direction. In other words, the rotation spacers 5 maintain the circumferential distance between the adjacent roller current collectors 4.

[0056] The rotary connector 1 of this embodiment is designed to be less susceptible to the generation of wear particles, as will be explained in detail below.

[0057] 1 and 3, the large diameter body portion 23 of the conductive shaft 20 has, at its axial center, an outer peripheral surface 23a that extends linearly along the axis of the large diameter body portion 23. In other words, the cross-sectional area of ​​the axial center of the large diameter body portion 23 when broken in the radial direction is approximately constant throughout the axial direction.

[0058] The large-diameter body portion 23 has annular flanges 27 formed on both axial ends thereof, which extend radially outward beyond the outer circumferential surface 23 a. The large-diameter body portion 23 also has annular grooves 28 formed therein, which extend circumferentially toward the axial center beyond the flanges 27.

[0059] The upper flange 27 and the lower flange 27 are vertically symmetrical. The upper groove 28 and the lower groove 28 are also vertically symmetrical. In the following description, the upper flange 27 and the groove 28 will be illustrated with reference to Figure 3, and the description of the lower flange 27 and the groove 28 will be omitted or simplified.

[0060] 3, the groove 28 is a U-shaped groove that is recessed radially inward from the outer peripheral surface 23a of the large-diameter body portion 23 and opens radially outward. The groove 28 has an inner inclined surface 28a that is continuous with the axial upper end of the outer peripheral surface 23a of the large-diameter body portion 23, an outer inclined surface 28b that is continuous with the outer peripheral surface of the flange 27, and a curved surface 28c that is continuous with the inner inclined surface 28a and the outer inclined surface 28b.

[0061] The inner inclined surface 28a is inclined radially inward from the axial upper end of the outer circumferential surface 23a of the large diameter body portion 23 and extends axially upward.

[0062] The inner inclined surface 28a is inclined radially inward by approximately 30 degrees from the outer circumferential surface 23a. In other words, the angle formed by the solid portion between the outer circumferential surface 23a and the inner inclined surface 28a is approximately 150 degrees.

[0063] The outer inclined surface 28b is inclined radially inward from the axially lower end of the outer peripheral surface of the flange 27 and extends axially downward.

[0064] The outer inclined surface 28b is inclined radially inward by approximately 60 degrees from the outer peripheral surface of the flange 27. In other words, the angle formed by the solid portion between the outer peripheral surface and the outer inclined surface 28b is approximately 120 degrees.

[0065] The curved surface 28c is curved so as to protrude toward the inner diameter side.

[0066] The roller current collector 4 is disposed so that its axial end 4a radially overlaps with the groove 28. In other words, the groove 28 is disposed at the position of the axial end 4a of the roller current collector 4.

[0067] Even if the axis of the roller current collector 4 tilts with respect to the axis of the conductive shaft 20, the corners 4b on the outer circumferential side of the axial end portions 4a move into the spaces within the grooves 28. In other words, the corners 4b of the roller current collector 4 are unlikely to come into contact with the inner inclined surface 28a or the curved surface 28c. In other words, the roller current collector 4 is unlikely to come into uneven contact with the conductive shaft 20.

[0068] In addition, the angle between the outer peripheral surface 23 a and the inner inclined surface 28 a on the solid side is approximately 150 degrees, which makes it easier to reduce the force generated by contact between the roller current collector 4 and the corner 23 b of the large diameter body portion 23.

[0069] The inclination angle of the inner inclined surface 28a with respect to the outer peripheral surface 23a is preferably in the range of 1 degree to 45 degrees, and is particularly preferably 30 degrees as described above. This is from the viewpoint of preventing contact between the axial end edge of the roller current collector 4 and the inner inclined surface 28a, and from the viewpoint of reducing the force generated by contact between the roller current collector 4 and the large diameter trunk portion 23.

[0070] The corner 4b of the roller current collector 4 is movable within a range from a position above the corner 23b where the outer peripheral surface 23a of the large diameter body portion 23 intersects with the inner inclined surface 28a (see Figure 3) to abutting the outer inclined surface 28b.

[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 outer inclined surface 28b, the axial end 4a elastically deforms toward the outer diameter side and the axial center. The resulting elastic force moves the roller current collector 4 toward the axial center, maintaining the axial position of the roller current collector 4 so that the axial end 4a radially overlaps the groove 28.

[0072] From this viewpoint, the inclination angle of the outer inclined surface 28b relative to the outer peripheral surface of the flange 27 is preferably in the range of more than 0 degrees and less than 90 degrees, and more preferably in the range of approximately 30 degrees to 60 degrees.

[0073] As described above, in the rotary connector 1 of this embodiment, the axial end 4 a of the roller current collector 4 is less likely to come into partial contact with the conductive shaft 20, reducing the force generated by contact with the conductive shaft 20. This allows the rotary connector 1 to suppress the generation of wear powder.

[0074] The roller current collector 4 is in line contact with the conductive shaft 20. It is well known that in this line contact area, stress at both axial ends is higher than stress at the axial center. In the rotary connector 1 of this embodiment, stress generated at the corner 4b of the roller current collector 4 is reduced, making it difficult for edge load due to stress concentration to occur at the corner 4b.

[0075] The roller current collector 4 of this embodiment has a thickness of 1 mm or less, and the cross section of the thin plate portion at the corner 4b has a knife-edge shape. As described above, edge load is unlikely to occur at the corner 4b, so the generation of wear powder can be effectively suppressed. The thickness of the roller current collector may be changed as appropriate. Furthermore, the axial end edges of the roller current collector may be chamfered.

[0076] Furthermore, the axial end 4 a of the roller current collector 4 is arranged to overlap the groove 28 in the radial direction, which makes it difficult for wear powder to become caught between the roller current collector 4 and the conductive shaft 20. Furthermore, since wear powder is likely to be generated on the axial end 4 a side of the roller current collector 4, it is likely to accumulate in the groove 28.

[0077] The grooves 28 are formed on both axial ends, thereby reducing the frequency with which the axially upper end 4 a or the axially lower end 4 a of the roller current collector 4 comes into partial contact with the conductive shaft 20, and reducing the force generated when the axially upper end 4 a or the axially lower end 4 a comes into contact with the conductive shaft 20.

[0078] Furthermore, since the groove 28 is formed in the conductive shaft 20, it is easy to form.

[0079] Furthermore, since the groove 28 is continuous with the flange 27, wear powder generated when the roller current collector 4 comes into contact with the flange 27 can be quickly collected.

[0080] The groove 28 is annular and extends in the circumferential direction, which more reliably reduces the frequency of the axially upper end 4 a or the axially lower end 4 a of the roller current collector 4 coming into partial contact with the conductive shaft 20, and the force generated when the axially upper end 4 a or the axially lower end 4 a comes into contact with the conductive shaft 20.

[0081] Furthermore, in the rotary connector 1, the upper slinger 22 is disposed axially above the large-diameter body portion 23. This makes it difficult for generated wear powder to become caught in the upper bearing 41. In other words, the wear powder is trapped below the upper slinger 22, making it easier for the wear powder to accumulate in the upper or lower groove 28.

[0082] Furthermore, in the rotary connector 1, the lower slinger 21 is disposed axially below the large-diameter body portion 23. This makes it difficult for generated wear powder to become caught in the lower bearing 40. In other words, wear powder is trapped above the lower slinger 21, making it easier for the wear powder to accumulate in the upper or lower grooves 28.

[0083] Next, a rotary connector according to a second embodiment will be described with reference to Fig. 4. Note that the description of the same configuration as in the first embodiment will be omitted.

[0084] As shown in FIG. 4, the conductive shaft 120 of this embodiment has an axially upper groove 28 and an axially lower groove 128 formed in its large diameter body portion 123.

[0085] The lower groove 128 has a longer axial dimension, i.e., width, than the upper groove 28. In other words, the lower groove 128 has a larger volume than the upper groove 28.

[0086] With this configuration, the lower groove 128 can make it difficult for wear powder that has fallen due to gravity to become caught between the axial lower end of the roller current collector 4 and the large diameter body portion 123. In addition, the lower groove 128 makes it easy to collect wear powder that has fallen due to gravity.

[0087] Although the example shows a structure in which the lower groove has a longer axial dimension than the upper groove, this is not limited to this, and the lower groove may have a larger radial dimension, i.e., a deeper depth, than the upper groove, and may be changed as appropriate as long as its volume is larger than that of the upper groove.

[0088] Next, a rotary connector according to a third embodiment will be described with reference to Fig. 5. Note that the description of the same configuration as in the first embodiment will be omitted.

[0089] As shown in Fig. 5, the roller current collector 204 of this embodiment has an axial end 204c of its axial end portion 204a inclined outward in the axial direction. The axial end portion 204a is formed by pressing the axial end of the cylindrical roller current collector so that it is bent radially inward by approximately 60 degrees. The outer peripheral surface of the axial end 204c is an inclined surface 204d inclined radially inward. The inclination angle of this inclined surface 204d is approximately parallel to the inclination angle of the outer inclined surface 28b of the conductive shaft 20.

[0090] In addition, the corner 204b between the inclined surface 204d at the axial end 204c and the outer peripheral surface at the axial end 204a other than the axial end 204c is located at approximately the same axial position as the corner 4b of the roller current collector 4 in Example 1.

[0091] With this configuration, the inclined surface 204d of the axial end 204c is more likely to come into surface contact with the outer inclined surface 28b of the conductive shaft 20. This disperses the force generated when the inclined surface 204d of the axial end 204c comes into contact with the outer inclined surface 28b of the conductive shaft 20, making it less likely that wear powder will be generated.

[0092] The roller current collector 204 has an axial end 204c which increases its structural strength.

[0093] The inclination angle of the inclined surface of the roller current collector may be changed as appropriate.

[0094] Furthermore, the inclined surface of the roller current collector is not limited to a configuration in which it is bent by pressing, but may be a configuration in which the inclined surface is formed by cutting.

[0095] Next, a rotary connector according to a fourth embodiment will be described with reference to Fig. 6. Note that the description of the same configuration as in the first embodiment will be omitted.

[0096] 6, the conductive shaft 320 of this embodiment has an inner groove 329U in which a portion of the upper groove 328U is further recessed axially downward and radially inward. The upper groove 328U has an inner inclined surface 28a and an outer inclined surface 28b.

[0097] The conductive shaft 320 also has an inner groove 329D in which a portion of the lower groove 328D is further recessed axially downward and radially inward. The lower groove 328D has an inner inclined surface 28a and an outer inclined surface 28b.

[0098] With this configuration, wear powder that has entered the inner groove 329U or the inner groove 329D is less likely to scatter outward from the inner groove 329U or the inner groove 329D.

[0099] Next, a rotary connector according to a fifth embodiment will be described with reference to Fig. 7. Note that the description of the same configuration as in the first embodiment will be omitted.

[0100] 7, the rotating element 402 of this embodiment is formed by integrating the conductive shaft 420 and the upper slinger 422. With this configuration, the number of parts of the rotating element 402 can be reduced.

[0101] Next, a rotary connector according to a sixth embodiment will be described with reference to Fig. 8. Note that the description of the same configuration as in the first embodiment will be omitted.

[0102] 8, in the rotary connector 501 of this embodiment, a flange 527 and a groove 528 are provided on a conductive ring 530 (see the enlarged view in the balloon), while the conductive shaft 520 does not have the flange or groove as in the first embodiment.

[0103] The flange 527 protrudes radially inward from an inner peripheral surface 530a at the axial upper or lower end of the conductive ring 530. The groove 528 is recessed radially outward from the inner peripheral surface 530a of the conductive ring 530, closer to the axial center than the flange 527, and is open radially inward.

[0104] With this configuration, the volume of the groove 528 can be made larger than that of the groove 28 formed in the conductive shaft 20 of the first embodiment. This makes it easier for wear powder to accumulate.

[0105] Furthermore, since the conductive ring 530 is a part of the stationary element 503, wear particles are less likely to scatter outward from the groove 528.

[0106] The conductive ring 530 may be a part of the rotating element, and the conductive shaft 20 may be a part of the stationary element. With this configuration, the centrifugal effect makes it more difficult for wear particles to scatter outward from the groove 528.

[0107] 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.

[0108] For example, in the first to sixth embodiments, the rotary connector is vertically oriented, but the present invention is not limited to this, and the rotary connector may be horizontally oriented.

[0109] Furthermore, in the above-described Examples 1 to 6, 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.

[0110] In addition, in the first to sixth 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.

[0111] Furthermore, in Examples 1 to 5, grooves are provided only in the conductive shaft, and in Example 6, grooves are provided only in the conductive ring. However, this is not limited to this, and grooves may be provided in both the conductive shaft and the conductive ring.

[0112] Furthermore, in Examples 1 to 6, the grooves have been described as being annular and extending in the circumferential direction, but this is not limited to this, and they may be spiral and extend in the circumferential direction, or grooves that do not extend in the circumferential direction, or multiple grooves that do not extend in the circumferential direction may be formed in the circumferential direction, and may be modified as appropriate.

[0113] Furthermore, in Examples 1 to 6, one groove is formed at each of the upper and lower ends, but this is not limited to this. Only one groove may be formed at the upper or lower end in the axial direction, or three or more grooves may be formed in the axial direction, and the number and arrangement thereof may be changed as appropriate.

[0114] In addition, in the first to sixth embodiments, the flange has been described as having an outer inclined surface that defines a groove, but this is not limited thereto and the flange may simply have an end surface that extends in the radial direction. In other words, the shape of the flange may be changed as appropriate as long as it is capable of restricting the axial movement of the roller current collector.

[0115] In addition, in the first to sixth embodiments, the flange is described as being continuous with the groove, but this is not limiting, and the flange may be spaced apart from the groove in the axial direction, or the flange may be formed on a member other than the member on which the groove is formed, or other suitable modifications may be made. For example, the upper slinger or the lower slinger may also function as a flange that can restrict axial movement of the roller current collector.

[0116] REFERENCE SIGNS LIST 1 rotary connector 2 rotating element 3 stationary element 4 roller current collector 4a axial end 4b corner 5 rotating spacer 20 conductive shaft 23a outer circumferential surface 27 flange 28 groove 28a inner inclined surface 28b outer inclined surface 30 conductive ring 120 conductive shaft 128 groove 204 roller current collector 204a axial end 204d inclined surface 320 conductive shaft 328D, 328U groove 329D, 329U inner groove 402 rotating element 420 conductive shaft 422 upper slinger 501 rotary connector 503 stationary element 520 conductive shaft 527 flange 528 groove 530 conductive ring

Claims

1. A rotary connector comprising an annular conductive ring, a conductive shaft inserted into the conductive ring and arranged so as to be rotatable relative to the conductive ring, and a current collector arranged radially between the conductive ring and the conductive shaft, wherein at least one of the conductive ring and the conductive shaft has a groove formed at the axial end of the current collector.

2. A rotary connector according to claim 1, wherein said grooves are formed at both axial ends of said current collector.

3. A rotary connector according to claim 1, wherein said groove is formed in said conductive shaft.

4. A rotary connector according to claim 1, wherein said groove is formed in said conductive ring.

5. A rotary connector according to claim 1, wherein a flange is formed axially outward of said groove.

6. A rotary connector according to any one of claims 1 to 5, wherein said groove extends in the circumferential direction.

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