JP2006014511A - Rotary connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary connector in which the cost can be reduced by significantly shortening the required length of a flat cable. <P>SOLUTION: In the rotary connector where a rotor 2 having an inner tubular section 7b is coupled rotatably for a stator 1 having an outer tubular section 5a, a flat cable 3 is contained, while being turned over in an annular space 9 defined by the outer tubular section 5a and the inner tubular section 7b; and a holder 4 made of synthetic resin is arranged rotatably in the annular space 9; an inner wall portion 4f extending in the circumferential direction to surround the great portion of the inner tubular section 7b; a coupling wall 4g extending outward from the inner wall portion 4f along an opening 15; and an outer wall portion 4i, extending from the outside end of the coupling wall 4g toward the inner wall portion 4f, are provided on the annular plate portion 4a of the holder 4 so that the flat cable 3, fed out from the inner tubular section 7b through the opening 15 to the outer tubular section 5a side, is wound noncircularly around the outer wall surface of the inner wall portion 4f and the outer wall portion 4i. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotary connector incorporated in a steering device of an automobile and used as an electrical connection means for an air bag system or the like, and in particular, a flat cable has an inversion portion in an annular space defined between a rotor and a stator. It is related with the rotation connector wound by reverse direction via.

  A rotary connector uses one of a pair of rotatably connected housings as a rotor and the other as a stator, and a flat cable is housed and wound between the rotor and the stator. It is used as an electrical connection means for an airbag system or the like attached to a handle having a limited number of rotations. The flat cable is a belt-shaped body carrying a plurality of conductors, and a spiral type in which the flat cable is wound in a spiral shape and a reverse type in which the flat cable is reversed in the middle and wound in the opposite direction are known. The length of the flat cable required for the inversion type can be shortened.

Conventionally, in such a reversing type rotary connector, a flat cable is housed in an annular space defined between a rotor and a stator in a state where the winding direction is reversed halfway, and a plurality of rollers are placed in the annular space. A holder in which a pivotally supported holder is rotatably arranged and a reversing portion of a flat cable is looped around one roller is known (for example, see Patent Document 1). In the rotary connector configured as described above, when the rotor rotates in either the forward or reverse direction with respect to the stator, the flat cable is drawn out from the outer cylindrical portion of the stator and wound around the inner cylindrical portion of the rotor. On the contrary, the flat cable is drawn out from the inner cylinder portion and is rewound onto the outer cylinder portion. At that time, the reversing part of the flat cable moves in the same direction by a smaller amount of rotation than the rotor, and the holder also moves in the same direction following this reversing part. The flat is about twice as long as the amount of movement. The cable is fed out from the outer cylinder part or the inner cylinder part. Further, since the movement of the flat cable in the radial direction is restricted by the plurality of rollers pivotally supported by the holder, the flat cable can be smoothly fed out in the direction of the reversing portion.
Japanese Patent Laid-Open No. 2001-126836 (page 2-3, FIG. 4)

  In this type of rotary connector, the ratio of the flat cable in the total cost is very high, and the cost can be reduced as the length of the flat cable required becomes shorter. In the reversing type rotary connector, the length of the flat cable can be shortened to about half at most as compared with the spiral type, and this is a major factor that hinders further cost reduction.

  The present invention has been made in view of the actual situation of the prior art, and an object of the present invention is to provide a rotary connector capable of reducing the cost by significantly reducing the length of a required flat cable. It is in.

  In order to achieve the above object, a rotary connector according to the present invention includes a stator having an outer cylinder portion, and an inner cylinder portion that is rotatably connected to the stator and defines an annular space between the outer cylinder portion. And a flat cable in which both ends thereof are led out to the outside through the inner cylinder part and the outer cylinder part, and the annular ring. A holder that is rotatably arranged in the space and has an opening through which the inversion portion of the flat cable passes, and an inner wall portion that extends in the circumferential direction so as to surround most of the inner cylinder portion. A connecting wall extending outwardly from the inner wall portion along the opening, and an outer wall portion extending from an outer end portion of the connecting wall toward the inner wall portion, wherein the flat cable extends from the inner tube portion to the opening. Through the holder And configured to be wound in a non-circular shape and said inner wall portion and the outer wall.

  In the rotary connector configured as described above, for example, when the rotor is rotated in one of the forward and reverse directions when the flat cable is wound around the outer wall of the inner cylinder part, the flat cable first drawn out from the inner cylinder part Is wound around the inner wall of the outer cylinder part through the opening of the holder, and then the rotor is further rotated in the same direction, whereby the inner wall provided with the flat cable wound on the inner wall side of the outer cylinder part The part and the outer wall surface of the outer wall part are wound in a non-circular shape to be in a rewound state. On the contrary, when the rotor is rotated in either direction from the state where the flat cable is rewound onto the inner wall portion and the outer wall portion of the holder, the flat cable is first drawn out from the inner wall portion and the outer wall portion of the holder, and then the outer cylinder. The flat cable wound around the inner wall of the outer tube is wound around the outer wall of the inner tube and is in a tightened state by further rotating the rotor in the same direction after being wound around the inner wall of the tube . In other words, the flat cable is once wound around the inner wall of the outer tube part in the middle from the tightened state to the unwinded state, but in the unwound state, the flat cable is the inner wall part and the outer wall part of the holder disposed in the annular space. Since the total length along the circumferential direction of the inner wall portion and the outer wall portion is sufficiently shorter than the total length along the circumferential direction of the inner wall surface of the outer cylinder portion, the required length of the flat cable is The length can be greatly shortened. In addition, since the flat cable is guided by the inner wall portion, the connecting wall, and the outer wall portion provided in the holder, the holder can be reduced in weight and cost, and the rotor can be smoothly rotated.

  In the above configuration, when the holder has an annular flat plate portion having an outer diameter substantially the same as the inner diameter of the outer cylinder portion, and the inner wall portion, the connecting wall, and the outer wall portion are erected on the annular flat plate portion, the holder Can be smoothly rotated in the annular space.

  In the above configuration, it is preferable that a roller is rotatably supported on the holder and the roller is opposed to the connecting wall through the opening, so that the reversal portion of the flat cable can smoothly pass through the opening. In this case, the holder is provided with an opposing wall that opposes the connecting wall through the opening and the roller, and the inner end of the opposing wall is continued to the inner wall, and the outer end of the opposing wall extends toward the inner wall. Providing the outer wall portion is preferable because the flat cable can be wound around the inner wall portion and the pair of outer wall portions in a non-circular shape.

  The rotary connector according to the present invention is provided in a circumferential direction so as to surround most of the inner cylinder portion in a holder rotatably disposed in an annular space between the inner cylinder portion of the rotor and the outer cylinder portion of the stator. An extending inner wall portion, a connecting wall extending outwardly from the inner wall portion along an opening through which the inversion portion of the flat cable passes, and an outer wall portion extending from the outer end portion of the connecting wall toward the inner wall portion are provided. Since the cable is wound around the inner wall part and the outer wall part of the holder through the opening from the inner cylinder part in a non-circular shape, the inner wall part having a short total length along the circumferential direction compared to the outer cylinder part of the stator, The flat cable is wound around the outer wall portion to be in a rewound state, and the required length of the flat cable can be greatly shortened accordingly. Further, since the flat cable is guided by the inner wall portion, the connecting wall, and the outer wall portion provided in the holder, the holder can be reduced in weight and cost, and the rotor can be smoothly rotated.

  An embodiment of the invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of a rotary connector according to an embodiment of the present invention, FIG. 2 is a sectional view of the rotary connector, and FIG. FIG. 4 is an operation explanatory view of the rotary connector.

  As shown in FIGS. 1 to 3, the rotary connector according to this embodiment includes a stator 1, a rotor 2 that is rotatably connected to the stator 1, and an electrical connection between the stator 1 and the rotor 2. A flat cable 3 to be connected and a holder 4 that is rotatably disposed between the stator 1 and the rotor 2 are schematically configured.

  The stator 1 is a fixing member fixed to the steering column, and the stator 1 includes a synthetic resin case 5 and a cover 6. The case 5 has an outer cylinder part 5a and a lid part 5b protruding from its outer wall, and the cover 6 has a bottom plate part 6a and a lower storage part 6b protruding from its outer edge. A center hole 6c is formed at the center of the bottom plate portion 6a. By integrating the lower end of the case 5 and the outer edge portion of the cover 6 by snap coupling, the lower opening end of the outer cylinder portion 5a is formed by the bottom plate portion 6a. While being closed, the upper opening end of the lower storage portion 6b is closed by the lid portion 5b.

  The rotor 2 is a movable member connected to the handle side. The rotor 2 includes an upper rotor 7 and a lower rotor 8 made of synthetic resin. The upper rotor 7 has an annular top plate portion 7a and an inner cylinder portion 7b hanging from the center thereof, and an upper storage portion 7c is erected on the top surface of the top plate portion 7a. The inner cylinder portion 7b has an inner diameter that can be inserted into the steering shaft, and the lower rotor 8 is integrated with the inner peripheral surface of the inner cylinder portion 7b. The lower rotor 8 is a cylindrical body having a flange portion 8a. The lower rotor 8 is inserted into the center hole 6c of the cover 6 and snap-coupled to the inner cylinder portion 7b, whereby the rotor 2 rotates with respect to the stator 1. It is designed to be freely connected. In this connected state, an annular space 9 having a ring shape in plan view is defined by the outer cylindrical portion 5a and bottom plate portion 6a on the stator 1 side, and the top plate portion 7a and inner cylindrical portion 7b on the rotor 2 side. .

  The flat cable 3 is formed of a strip-like body in which a plurality of conductors parallel to each other are laminated with a pair of insulating films. The flat cable 3 is accommodated in the annular space 9 in the reverse direction via a U-shaped inversion portion 3a. . Lead blocks 10 and 11 are connected to both ends of the flat cable 3, respectively. One lead block 10 is fixed in the lower housing portion 6b of the cover 6, and a lead wire 12 having an external connector 12a at the tip is connected to the lead block 10. The other lead block 11 is fixed in the upper storage portion 7c of the upper rotor 7, and a lead wire 13 having an external connector 13a at the tip is connected to the lead block 11.

  The holder 4 has an annular flat plate portion 4a placed on the bottom plate portion 6a of the cover 6, and a guide portion 4b and a support shaft 4c erected on the annular flat plate portion 4a. These are made of synthetic resin. It is integrally molded. The annular flat plate portion 4a has substantially the same outer diameter as the inner diameter of the outer cylinder portion 5a, and a circular center hole 4d is formed at the center of the annular flat plate portion 4a. This center hole 4d is inserted in the lower outer peripheral surface of the inner cylinder part 7b, and the holder 4 can rotate in the annular space 9 while slidingly contacting the inner cylinder part 7b. Further, a protrusion 4e is formed on the lower surface of the annular flat plate portion 4a, and the sliding resistance between the annular flat plate portion 4a and the bottom plate portion 6a is reduced by the protrusion 4e.

  As shown in FIG. 3, the guide portion 4b includes an inner wall portion 4f extending in an annular shape so as to surround most of the center hole 4d, and a connection extending from both ends of the inner wall portion 4f toward the outer edge portion of the annular flat plate portion 4a. The wall 4g and the opposing wall 4h, and the first and second outer wall parts 4i and 4j extending from the outer ends of the connecting wall 4g and the opposing wall 4h toward the inner wall part 4f, respectively, are substantially the same. It is continuously formed with the same wall thickness. The connecting wall 4g and the opposing wall 4h face each other via a support shaft 4c, and a roller 14 is rotatably supported on the support shaft 4c. The aforementioned reversing portion 3a of the flat cable 3 is positioned in the opening 15 secured between the roller 14 and the connecting wall 4g facing the roller 14, and the outer cylinder passes through the opening 15 from the inner cylinder portion 7b. The flat cable 3 toward the portion 5a is wound non-circularly around the inner wall portion 4f and the outer wall surfaces of the first and second outer wall portions 4i and 4j. If this winding portion is a non-circular winding surface P, the distance from the center O of the center hole 4d (that is, the rotation center of the rotor 2) to the non-circular winding surface P is the vicinity of the opening 15 where the roller 14 is supported. Is the largest, gradually decreases along the extending direction of the first and second outer wall portions 4i, 4j, and the half portion of the inner wall portion 4f facing the roller 14 180 degrees is the smallest.

  Next, the operation of the rotary connector configured as described above will be described mainly with reference to FIG. In FIG. 4, the stator 1 and the rotor 2 including the outer cylinder portion 5a and the inner cylinder portion 7b are omitted.

  FIG. 4 (a) shows a tightening state in which most of the flat cable 3 is wound around the outer wall of the inner cylindrical portion 7b. When the rotor 2 is rotated counterclockwise (arrow A direction) from this tightening state, Since the reversing portion 3a of the flat cable 3 moves counterclockwise by a rotation amount smaller than that of the rotor 2, the roller 14 and the holder 4 also move counterclockwise following this reversing portion 3a. As shown in b), the flat cable 3 which is about twice as much as the amount of movement is drawn out from the inner cylinder part 7b side and wound around the inner wall of the outer cylinder part 5a. In this case, since the inner wall portion 4f is annularly extended so as to surround most of the center hole 4d, the flat cable 3 fed out from the inner cylindrical portion 7b side bulges outward and buckles and deforms. Instead, the flat cable 3 passes through the opening 15 and is reliably fed out to the outer tube portion 5a side. When the rotor 2 is further rotated in the counterclockwise direction, as shown in FIG. 4C, the flat cable 3 is drawn out from the outer cylindrical portion 5a side, and the inner wall portion 4f of the holder 4 and the first and second A rewound state in which the outer wall portions 4i and 4j are wound around the outer wall surface (that is, the non-circular winding surface P), and finally the flat cable 3 is wound around the guide portion 4b of the holder 4 in a non-circular shape. Become.

  Contrary to the above, when the rotor 2 is rotated in the clockwise direction (arrow B direction) from the unwinding state shown in FIG. 4C, the flat cable 3 is drawn out from the guide portion 4b side of the holder 4 and the outer cylinder portion. After being wound around the inner wall of 5a, the rotor 2 was further rotated in the clockwise direction, so that most of the flat cable 3 was wound around the outer wall of the inner cylindrical portion 7b as shown in FIG. It will be in a tightened state.

  As described above, in the rotary connector according to this embodiment, the flat cable 3 is in the middle of being in the tightened state shown in FIG. 4 (a) or in the unwinded state shown in FIG. 4 (c). As shown in FIG. 2, the flat cable 3 is once wound around the outer cylinder part 5a located outside the holder 4, and is wound around the guide part 4b of the holder 4 as compared with the circumferential length of the inner wall surface of the outer cylinder part 5a. Since the circumferential length of the non-circular winding surface P is sufficiently short, the required length of the flat cable 3 can be greatly shortened.

The shortening effect of the flat cable 3 will be described with reference to FIG. 5. FIG. 5 (a) shows a conventional rotary connector in which the flat cable is wound around the outer cylinder portion to be rewound, and FIG. The rotary connector according to the present embodiment in which the flat cable is wound around the guide portion of the holder to be in the unwinding state. In these rotary connectors, the inner diameter (diameter dimension of the tightened state) of the path of the flat cable is r, If the outer diameter of the path of the flat cable (the diameter dimension in the rewind state) is R, and the finite number of rotations of the rotor is N, the required length L of the flat cable 3 is (L / rπ) + (L / From Rπ) = N,
L = rR × Nπ / (r + R) (1)
As given. Here, the inner diameter r corresponds to the outer diameter of the inner cylinder portion of the rotor. Due to the structure in which the inner cylinder portion is inserted into the steering shaft, the inner diameter r is the same as that of the rotary connector shown in FIG. The rotary connector shown in FIG. As for the outer diameter R, in the case of the rotary connector shown in FIG. 5 (a), the outer diameter R corresponds to the inner diameter of the outer cylinder portion, but in the case of the rotary connector shown in FIG. The diameter R corresponds to the outer diameter of the non-circular winding surface P and is smaller than the inner diameter of the outer cylinder portion. In FIG. 5B, the outer diameter R is attached to a virtual circle indicated by a one-dot chain line, because the non-circular winding surface P is not circular, and the non-circular inscribed in this virtual circle. The substantial outer diameter of the winding surface P is further smaller than the outer diameter R of the virtual circle. Therefore, as apparent from the above equation (1), the outer diameter R of the present embodiment shown in FIG. 5B is much smaller than that of the conventional example shown in FIG. The length L of the flat cable 3 can be shortened while ensuring the finite rotation speed N constant. For example, when the outer diameter of the inner cylinder part is 50 mm, the inner diameter of the outer cylinder part is 100 mm, the substantial outer diameter is 70 mm when the noncircular winding surface P is a virtual circle, and the finite number of rotations of the rotor is six. In the case of a conventional rotary connector, if r = 50 mm, R = 100 mm, and N = 6 are substituted into the above equation (1), L = 628 mm. On the other hand, in the case of the rotary connector according to this embodiment, when r = 50 mm, R = 70 mm, and N = 6 are substituted into the above equation (1), L = 549.5 mm is obtained, and the required length of the flat cable 3 The length L can be shortened by 78.5 mm.

  In the above-described embodiment, the case where the first and second outer wall portions 4i and 4j are connected to the connecting wall 4g of the guide portion 4b and the outer end portion of the opposing wall 4h has been described. Since the flat cable 3 is looped around the roller 14 and wound around the outer peripheral surface of the inner wall portion 4f, the non-circular winding surface P is formed only by the first outer wall portion 4i extending from the outer end portion of the connecting wall 4g. The second outer wall portion 4j extending from the outer end portion of the opposing wall 4h can be omitted.

  In the above embodiment, the rotary connector using one flat cable has been described, but it goes without saying that the present invention can be applied to a double-winding type rotary connector using two flat cables stacked together. Absent.

It is a disassembled perspective view of the rotation connector which concerns on the example of embodiment of this invention. It is sectional drawing of this rotation connector. It is a top view of the holder with which this rotation connector is equipped. It is operation | movement explanatory drawing of this rotation connector. It is explanatory drawing which shows the comparative example of the shortening effect of a flat cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator 2 Rotor 3 Flat cable 3a Inversion part 4 Holder 4a Annular flat plate part 4b Guide part 4c Support shaft 4d Center hole 4f Inner wall part 4g Connection wall 4h Opposing wall 4i First outer wall part 4j Second outer wall part 5 Case 5a Outside Tube portion 6 Cover 6a Bottom plate portion 7 Upper rotor 7a Top plate portion 7b Inner tube portion 8 Lower rotor 9 Annular space 14 Roller 15 Opening P Non-circular winding surface

Claims (4)

A stator having an outer cylindrical portion, a rotor rotatably connected to the stator and provided with an inner cylindrical portion that defines an annular space between the outer cylindrical portion, and a winding direction in the middle of the annular space And a flat cable in which both ends thereof are led out to the outside via the inner cylinder part and the outer cylinder part, and a reversing part of the flat cable, which is rotatably arranged in the annular space. A holder having an opening through which
The holder includes an inner wall portion extending in the circumferential direction so as to surround most of the inner cylinder portion, a connecting wall extending outward from the inner wall portion along the opening, and an outer end portion of the connecting wall from the outer end portion. An outer wall portion extending toward the inner wall portion is provided, and the flat cable is wound around the inner wall portion and the outer wall portion of the holder in a non-circular shape from the inner tube portion through the opening. A rotary connector characterized by that.   The holder according to claim 1, wherein the holder has an annular flat plate portion having an outer diameter that is substantially the same as the inner diameter of the outer cylinder portion, and the inner wall portion, the connecting wall, and the outer wall portion stand on the annular flat plate portion. A rotary connector characterized by being provided.   The rotary connector according to claim 1 or 2, wherein a roller is rotatably supported on the holder, and the roller is opposed to the connecting wall through the opening. The counter wall according to claim 3, wherein the holder is provided with a facing wall facing the connecting wall through the opening and the roller, and an inner end portion of the facing wall is continued to the inner wall portion, and an outer side of the facing wall is provided. A rotary connector characterized in that another outer wall portion extending toward the inner wall portion is provided at an end portion.

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