JP2015103772A - Non-contact rotation transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact rotation transmission device which transmits both power and a signal in a non-contact manner while ensuring reliability of transmission between signal coils and excellently reduces its weight.SOLUTION: A first member 21 on which a shaft 23 projecting from the center of a main body 22 is provided rotates, around a rotation axis 31, relatively with respect to a second member 25. The shaft 23 is configured by a cylindrical electromagnetic shield 15 whose both ends are open. A pair of power coils 11 are disposed so as to be opposite to each other through a gap Gp and are disposed outside the shaft 23. A pair of signal coils 13 having a gap Gs include a signal coil 13 of the first member 21 which is disposed inside the cylinder of the electromagnetic shield 15 so that the signal coil 13 is separated to the second member 25 side from the same surface as the opposing surface 11B of the power coil 11 of the second member 25. The electromagnetic shield 15 is provided so as to cross the gap Gp between the power coils 11.

Description

  The present invention relates to a contactless rotation transmission device that transmits power and signals in a contactless manner.

  2. Description of the Related Art A flat cable wound in a spiral shape is known as a connector for electrically connecting a rotation-side steering wheel and a vehicle-fixed bracket to which a steering column is attached in a vehicle.

  However, when a flat cable is used, since there is a limitation on rotation, a non-contact rotation transmission device that is electrically connected to each other in a non-contact manner has been studied.

  In such a conventional non-contact rotation transmission device, as shown in FIG. 5, a secondary side core 64 and a primary side core 63 are fixed to a steering wheel 61 and a bracket 62, respectively. The primary side core 63 and the secondary side core 64 are each formed with two annular grooves, and a power coil 65 and a signal coil 66 are embedded in the grooves. A gap G is maintained between the primary side core 63 and the secondary side core 64, and the primary side coil and the secondary side coil of the power coil 65 and the signal coil 66 are opposed to each other. Then, both the power and the signal can be transmitted in a non-contact manner by electromagnetic induction between the primary side coil and the secondary side coil while the steering wheel 61 is rotatable with respect to the bracket 62.

  In addition, as prior art document information relevant to the invention of this application, for example, what is shown in Patent Document 1 is known.

JP 2000-269057 A

  Such a conventional non-contact rotary transmission device has a problem that a transmission error occurs in the signal coil 66 due to the magnetic flux of the power coil 65 and the transmission reliability deteriorates.

  The present invention provides a non-contact rotary transmission device that ensures the reliability of transmission between signal coils and transmits both power and signals in a non-contact manner and is excellent in weight reduction.

  In order to achieve the above object, the present invention provides a pair of power coils and a pair of signals provided on a first member and a second member, which are relatively rotated, and arranged to face each other with a gap. A coil and a cylindrical electromagnetic shield having a shaft protruding from the center of the main body of the first member and open at both ends, wherein the electromagnetic shield is a pair of the electromagnetic shields disposed outside the shaft. The signal coil of the first member is provided so as to cross the gap between the power coils, and is the same as the opposite surface of the power coil of the second member on the opposite side to the side on which the power coil faces. It is a non-contact rotation transmission device disposed in the cylinder of the electromagnetic shield away from the surface toward the second member.

  As described above, according to the present invention, the electromagnetic shield is provided so as to cross the gap between the pair of power coils, and the signal coil of the first member is the same as the opposite surface of the power coil of the second member. By being disposed away from the surface toward the second member, the magnetic flux leaking from the gap between the power coils can be blocked by the electromagnetic shield, and the influence on the signal coil can be reduced. Furthermore, since the shielding effect can be enhanced without providing an electromagnetic shield around the entire power coil, the weight of the member can be reduced.

Front sectional view of the non-contact rotation transmission apparatus in the first embodiment Front sectional view of a non-contact rotary transmission device provided with an opposing electromagnetic shield in the second embodiment Front sectional view of a non-contact rotary transmission device in which the end side in Embodiment 3 is provided wide Front sectional view of a non-contact rotation transmission device provided with a magnetic body in the fourth embodiment Front sectional view of a conventional non-contact rotary transmission device

(Embodiment 1)
The non-contact rotation transmission apparatus of Embodiment 1 will be described.

  FIG. 1 is a front cross-sectional view of the non-contact rotary transmission device according to the first embodiment. As shown in FIG. 1, the contactless rotation transmission apparatus of the first embodiment has a first member 21 and a second member 25 that rotate relatively around a rotation shaft 31 and a gap Gp that faces each other. A pair of power coils 11 provided, and a pair of signal coils 13 arranged to face each other with a gap Gs are provided.

  Although the 1st member 21 is a rotation side and the 2nd member 25 is a fixed side, it is not limited to this, The 1st member 21 and the 2nd member 25 should just be able to rotate relatively.

  The pair of power coils 11 are planar coils, and transmit power in a non-contact manner by electromagnetic induction between the coils.

  The pair of signal coils 13 is a planar coil concentrically provided with the pair of power coils 11 and is used as an antenna that transmits signals in a non-contact manner by electromagnetic coupling between the coils, and performs high-speed data transmission. It can be carried out. The pair of signal coils 13 may transmit signals by electromagnetic induction.

  The first member 21 includes a main body 22 having a substantially circular outer periphery, and a shaft 23 that protrudes perpendicularly from the center of the main body 22 toward the second member 25 side. The electromagnetic shield 15 has a cylindrical shape with both ends opened, and constitutes at least a part of the shaft 23.

  An annular groove 45 in which the power coil 11 of the first member 21 is accommodated is formed in the main body 22 of the first member 21.

  The second member 25 is disposed to face the first member 21, the central portion 26 corresponding to the shaft 23 of the first member 21 is provided in a concave shape, and the circumferential surface along the rotation shaft 31 of the central portion 26 is A shaft 23 and a gap are provided along the body. By providing a ball bearing 33 in the gap, the first member 21 can freely rotate with respect to the second member 25 about the shaft 23.

  The power coil 11 of the second member 25 is housed in an annular groove 46 formed in the flat portion 27 on the outer peripheral side of the second member 25. The signal coil 13 of the second member 25 is disposed on the bottom surface of the concave central portion 26.

  The pair of power coils 11 is disposed outside the shaft 23, and the electromagnetic shield 15 is provided so as to cross the gap Gp between the power coils 11. That is, one end 41 on the upper end side of the electromagnetic shield 15 is disposed at least on the same plane as the power coil 11 of the first member 21. This plane is perpendicular to the rotation axis 31. Further, the upper end portion 41 of the electromagnetic shield 15 may be arranged to extend upward from the power coil 11 of the first member 21. Thereby, the magnetic flux leaking from the gap Gs between the power coils 11 can be shielded, the influence of the magnetic flux of the power coil 11 on the signal coil 13 can be reduced, and deterioration of transmission can be suppressed.

  The upper end portion 41 of the electromagnetic shield 15 is preferably disposed on the same surface as the opposing surface 11A of the power coil 11 of the first member 21 where the pair of power coils 11 face each other. The weight can be reduced while obtaining the shielding effect of the shield 15.

  The pair of signal coils 13 is disposed away from the same surface as the opposite surface 11B of the power coil 11 of the second member 25 toward the second member 25 side. Here, the opposite surface 11B of the power coil 11 is a surface that is perpendicular to the rotating shaft 31 and is opposite to the facing surface 11A where the pair of power coils 11 face each other.

  Further, among the pair of signal coils 13, at least the signal coil 13 of the first member 21 is disposed inside the cylinder of the electromagnetic shield 15. With this configuration, the influence of the magnetic flux of the power coil 11 on the signal coil 13 can be significantly reduced. At this time, the signal coil 13 of the second member 25 is provided outward from the other end 42 on the lower end side of the electromagnetic shield 15.

  The electromagnetic shield 15 is preferably made of a highly conductive metal, and can enhance the effect of reducing the influence of the magnetic flux of the power coil 11 on the signal coil 13. Furthermore, since the metal electromagnetic shield 15 has high mechanical strength, it can be used for the base material of the shaft 23 as a main material for maintaining high rigidity, and the number of parts can be reduced and the size can be reduced.

  As the metal of the electromagnetic shield 15, a nonmagnetic metal such as aluminum, SUS304 stainless steel, copper, brass or the like can be used. The electromagnetic shield 15 may be made of a conductive material such as a conductive resin. Further, the electromagnetic shield 15 may be formed with a coating film on the surface with a resin or the like for improving corrosion resistance, fixing the ball bearing 33, or the like. The shaft 23 may be configured by embedding the electromagnetic shield 15 in the resin molded body.

  Further, a rotation axis between the opposite surface of the first member 21 opposite to the signal coil 13 and the opposite surface 11B of the power coil 11 of the second member 25 on the side opposite to the side facing the signal coil 13. The distance H in the 31 direction is preferably 1/3 or more of the diameter of the outermost periphery of the power coil 11, more preferably about half or more of the diameter of the outermost periphery of the power coil 11, depending on the magnetic flux of the power coil 11. The influence on the signal coil 13 can be significantly reduced. Moreover, the distance H can be made smaller than the diameter of the outermost periphery of the power coil 11, and the shaft 23 can be reduced in size.

  As shown in FIG. 1, the shaft 23 is provided with a space between one end 41 of the electromagnetic shield 15 and the signal coil 13 of the first member 21. Thereby, the transmission loss of the signal coil 13 can be suppressed, and the shaft 23 can be reduced in weight.

  Further, the power coil 11 is preferably provided so as to be separated from the electromagnetic shield, and is provided so that the entire periphery of the power coil 11 except the facing surface 11A of the power coil 11 is not covered with the electromagnetic shield. The transmission loss between 11 can be reduced. Moreover, since the outer peripheral side of the rotating surface of the 1st member 21 can be reduced in weight, it is excellent in rotation ease and can save labor.

  A magnetic core may be provided around the power coil 11 in a ring shape along the power coil 11. Further, in order to improve the strength of the shaft 23, a nonmagnetic and insulating reinforcing portion may be provided inside the cylinder of the shaft 23 above the signal coil 13 of the first member 21.

  As described above, the contactless rotation transmission apparatus of the first embodiment can reduce the influence of the power coil on the signal coil, can coexist power transmission and signal transmission, and can be reduced in weight.

(Example)
Next, an embodiment will be described using the non-contact rotation transmission device shown in FIG. In FIG. 1, a shaft 23 is an electromagnetic shield 15 made of aluminum. The electromagnetic shield 15 is a cylinder having a length of 70 mm, an outer diameter of 60 mm, and an inner diameter of 40 mm, and is fixed to the main body 22 of the first member 21 made of nonmagnetic and insulating resin by screwing. Further, the gap Gp and the gap Gs are provided at 5 mm, and the power coil 11 is wound around a conductive wire with an outermost diameter of the coil being 150 mm and is fixed in the grooves 45 and 46 with an adhesive. The signal coil 13 is a planar coil formed on the surface of the circuit boards 47 and 48 or embedded in the circuit boards 47 and 48 and having a diameter of the outermost periphery of the coil of 20 mm. The circuit board 47 of the signal coil 13 of the first member 21 is made of a disk-shaped resin, and is fixed to the cylindrical inner surface of the shaft 23 where the distance H from the power coil 11 of the second member 25 is 55 mm. . The lead wire 49 of the coaxial cable connected to the signal coil 13 of the first member 21 is drawn out to the main body 22 side of the first member 21 through the inside of the cylinder of the shaft 23. Compared with the case where the electromagnetic shield 15 is not provided, the influence of the magnetic flux of the power coil 11 on the signal coil 13 can be reduced by about 30 dB. In the meantime, high-speed data transmission with a communication data rate of 3 Gbps can be performed.

(Embodiment 2)
Next, the non-contact rotation transmission apparatus according to the second embodiment will be described.

  FIG. 2 is a front cross-sectional view of a non-contact rotary transmission device provided with a counter electromagnetic shield in the second embodiment. The same parts as those shown in FIG. 1 are denoted by the same reference numerals, and a part thereof is simplified and drawn with a two-dot chain line, and detailed description thereof is omitted. The same applies to the same parts of FIG. 3 and FIG.

  As shown in FIG. 2, the opposing electromagnetic shield 16 may be provided on the second member 25 on the outer periphery of the signal coil 13 of the second member 25. The opposing electromagnetic shield 16 is provided in a cylindrical shape so as to face the other end 42 of the electromagnetic shield 15 with a gap Gm.

  Thus, by arranging the signal coil 13 of the second member 25 inside the cylinder of the opposed electromagnetic shield 16, the influence of the magnetic flux of the power coil 11 on the signal coil 13 can be further reduced.

  The axial length of the opposing electromagnetic shield 16 is about the same as the height of the signal coil 13 of the second member 25 and is shorter than the length of the electromagnetic shield 15. The gap Gm between the electromagnetic shield 15 and the opposed electromagnetic shield is equal to or smaller than the gap Gs between the signal coils 13 and communicates with the rotating shaft 31 in the vertical direction.

  The opposing electromagnetic shield 16 is preferably made of a highly conductive metal like the electromagnetic shield 15.

(Embodiment 3)
Next, the non-contact rotation transmission apparatus of Embodiment 3 will be described.

  FIG. 3 is a cross-sectional view of a non-contact rotary transmission device in which the end side of Embodiment 3 is provided wide. As shown in FIG. 3, the end 43 side of the electromagnetic shield 17 away from the power coil 11 of the second member 25 is provided wide, an enlarged hollow space 50 is formed on the end 43 side, and the electromagnetic shield 17 has a cross-section. It is provided in steps. A pair of signal coils 13 is disposed in the hollow cylinder of the enlarged hollow space 50.

  A base projecting toward the enlarged hollow space 50 is provided on the bottom surface of the central portion of the second member 28, and the signal coil 13 of the second member 28 is disposed in the enlarged hollow space 50 by this base.

  By arranging the pair of signal coils 13 in the enlarged hollow space 50 in this manner, the distance between the electromagnetic shield 17 and the signal coil 13 is provided so as to be separated. Characteristic deterioration can be reduced. In addition, the diameter of the upper end side of the shaft 23 can be reduced in accordance with the electromagnetic shield 17, and the weight can be reduced.

(Embodiment 4)
A non-contact rotation transmission apparatus according to the fourth embodiment will be described.

  FIG. 4 is a front cross-sectional view of a non-contact rotation transmission device provided with a magnetic body in the fourth embodiment. As shown in FIG. 4, it is preferable to further arrange a magnetic body 55 that covers the inside of the cylinder of the electromagnetic shield 15. By this magnetic body 55, the magnetic flux of the signal coil 13 can be converged, and the characteristic deterioration of the signal coil 13 due to the electromagnetic shield 15 can be reduced.

  As the magnetic body 55, Ni—Zn ferrite or Mn—Zn ferrite of soft magnetic ferrite can be used. The magnetic body 55 can be a ferrite resin core formed by mixing soft magnetic ferrite powder and a resin such as nylon or PSS, or a ferrite sintered core obtained by mixing soft magnetic ferrite powder and a binder and sintering. .

  The electromagnetic shield 15 and the ferrite resin core may be integrally formed by injection molding, and the magnetic body 55 may be covered on the inner side of the cylinder, or the sintered ferrite core may be inserted on the inner side of the cylinder.

  Further, the magnetic body 55 may be arranged in a disc shape so as to cover the opening of one end 44 of the electromagnetic shield 15.

DESCRIPTION OF SYMBOLS 11 Power coil 11A Opposite surface 11B Opposite surface 13 Signal coil 15, 17 Electromagnetic shield 16 Opposed electromagnetic shield 21 1st member 22 Main body 23 Shaft 25 2nd member 26 Central part 27 Flat part 28 2nd member 31 Rotating shaft 41, 42, 43, 44 End 50 Expanded hollow space 55 Magnetic body

Claims (7)

A pair of power coils and a pair of signal coils provided on the first member and the second member, respectively, which are relatively rotated, and are disposed facing each other with a gap;
A shaft projecting from the center of the main body of the first member, and a cylindrical electromagnetic shield having both ends opened; and
The electromagnetic shield is provided so as to cross a gap between a pair of the power coils disposed outside the shaft,
The signal coil of the first member is separated from the same surface as the opposite surface of the power coil of the second member on the side opposite to the side facing the power coil to the second member side, and the electromagnetic shield Non-contact rotation transmission device arranged inside the cylinder. The non-contact rotation transmission device according to claim 1, wherein one end of the electromagnetic shield is disposed on the same plane as the power coil of the first member. The non-contact rotary transmission device according to claim 1, wherein the shaft is provided between the one end of the electromagnetic shield and the signal coil of the first member so as to be hollow. A cylindrical opposed electromagnetic shield is provided on the second member so as to be opposed to the electromagnetic shield with a gap, and the signal coil of the second member is disposed inside the cylinder of the opposed electromagnetic shield. The non-contact rotation transmission apparatus according to 1. The non-contact rotary transmission device according to claim 1, wherein the electromagnetic shield is provided with a wide width at the other end side away from the power coil of the second member. The non-contact rotary transmission device according to claim 1, wherein the electromagnetic shield is a non-magnetic metal. The non-contact rotation transmission apparatus according to claim 1, wherein a magnetic body that covers a cylindrical inner surface side of the electromagnetic shield is provided.

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