JP2006024462A - Rotating connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotating connector capable of achieving reduction in cost by greatly shortening the necessary length of a flat cable. <P>SOLUTION: A rotor 2 provided with an interior cylinder 7b is connected to be freely rotated to a stator 1 provided with an exterior cylinder 5a. The flat cable 3 is stored in a reversed state in an annular space 9 formed between the exterior cylinder 5a and the interior cylinder 7b, and a holder 4 is disposed rotatably in the annular space 9 in the rotating connector. A guide body 4b is installed with an exterior wall made eccentric against an interior wall concentrically extended with the interior cylinder 7b on an annular flat plate 4a of the holder 4, and an opening 15 is provided through which the reversed part 3a of the flat cable 3 is passed in the maximum diameter of the guide body 4b. Further, recess and projection part 4g is formed as effectively reducing area of contact with the flat cable 3 on the exterior wall of the guide body 4b. <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 cylindrical portion, and an inner cylindrical portion that is rotatably connected to the stator and defines an annular space between the stator and the outer cylindrical 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 disposed in the space and has an opening through which the inversion portion of the flat cable passes, and the holder is provided with a guide body that extends so as to surround the inner cylinder portion with the opening as a base end In addition, the distance from the rotation center of the rotor to the outer wall surface of the guide body is set to be maximum in the vicinity of the opening compared to other portions, and the flat cable is connected to the outer wall surface of the guide body. of And forming an uneven portion for reducing the touching area.

  In the rotary connector configured in this way, for example, when the rotor is rotated in either the forward or reverse direction when the flat cable is wound around the outer peripheral surface of the inner cylinder portion, the flat cable is first drawn out from the inner cylinder portion. After the coil is wound around the inner peripheral surface of the outer cylinder portion, the guide body in which the flat cable wound around the inner peripheral surface side of the outer cylinder portion is provided on the holder by further rotating the rotor in the same direction. It is wound around the outer wall surface and is in a rewound state. On the other hand, when the rotor is rotated in any direction from the state where the flat cable is rewound onto the outer wall surface of the guide body, the flat cable is first drawn out from the outer wall surface of the guide body and then the inner circumference of the outer cylinder portion. After the wire is wound on the surface, the rotor is further rotated in the same direction, so that the flat cable wound on the inner peripheral surface side of the outer tube portion is wound on the outer peripheral surface of the inner tube portion and Become. That is, the flat cable is once wound around the inner peripheral surface of the outer cylinder part in the middle from the tightening state to the rewinding state, but in the rewinding state, the flat cable is a guide body of the holder disposed in the annular space. The entire length of the guide body that is wound around the outer wall surface along the circumferential direction of the guide body is sufficiently shorter than the entire length of the inner circumferential surface of the outer cylinder, so the required flat cable length is significantly reduced. can do. Moreover, since the concave and convex portions that reduce the contact area with the flat cable are formed on the outer wall surface of the guide body of the holder, the flat cable is smoothly fed out without being in close contact with the outer wall surface of the guide body during the tightening operation. Smooth rotation of the holder can be realized.

  In the above configuration, the specific shape of the concavo-convex portion is not particularly limited, for example, by interspersing a large number of hemispherical convex portions on the outer wall surface of the guide body or by forming the outer wall surface of the guide body in a wavy shape Although it is realizable, it is preferable to form a recessed part and a convex part alternately along the circumferential direction of the outer wall surface of a guide body especially. In addition, the guide body of the holder may extend so as to surround the inner cylinder portion with the opening through which the inversion portion of the flat cable passes as a base end. However, the guide body extends to the inner wall surface extending concentrically with the inner cylinder portion. It is preferable that the holder has a decentered outer wall surface and that a concave cavity is formed between the inner wall surface and the outer wall surface of the guide body, so that the holder can be reduced in weight and cost. Further, if 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 guide body is erected on the annular flat plate portion, the holder is smoothly rotated in the annular space. This is preferable.

  The rotary connector according to the present invention has an opening through which a reversing portion of a flat cable passes in a holder rotatably disposed in an annular space between an inner cylinder portion of a rotor and an outer cylinder portion of a stator. Since the guide body extending so as to surround the cylinder portion is provided, and the distance from the rotation center of the rotor to the outer wall surface of the guide body is set to be the maximum near the opening compared to other portions, The flat cable is wound around the outer wall surface of the small-diameter guide body as compared with the cylindrical portion to be in a rewind state, and the required length of the flat cable can be significantly shortened accordingly. In addition, since the concave and convex portions that reduce the contact area with the flat cable are formed on the outer wall surface of the guide body, the flat cable is smoothly fed out without being in close contact with the outer wall surface of the guide body during the tightening operation. Smooth rotation can be realized.

  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 circular guide hole 6c is formed at the center of the bottom plate portion 6a, and the lower end of the case 5 and the outer edge portion of the cover 6 are integrated by snap coupling so that the lower opening end of the outer cylinder portion 5a is the bottom plate portion. 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 8a. The lower rotor 8 is inserted into the guide hole 6c of the cover 6 and snap-coupled to the inner cylinder 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 body 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 cylindrical portion 5a, and a circular through hole 4d is formed at the center of the annular flat plate portion 4a. The through hole 4d is inserted into the lower outer peripheral surface of the inner cylinder portion 7b, and the holder 4 can rotate in the annular space 9 while slidingly contacting the inner cylinder portion 7b. Further, a protrusion 4e is formed on the lower surface of the annular flat plate portion 4a to reduce sliding resistance with the bottom plate portion 6a.

  The guide body 4b is erected on the annular flat plate portion 4a so as to surround most of the through hole 4d, and its inner wall is a circumferential surface substantially concentric with the through hole 4d, but the outer wall is a through hole. The circumferential surface is greatly decentered with respect to 4d. A concave cavity 4f is formed between the inner wall and the outer wall of the guide body 4b, and the weight of the entire holder 4 is reduced by the cavity 4f. Furthermore, a concavo-convex portion 4g is formed on most of the outer wall surface of the guide body 4b, and the concavo-convex portion 4g is formed by alternately continuing the concave portion and the convex portion along the circumferential direction. A part of the guide body 4b is cut out on the annular flat plate portion 4a, and a cylindrical support shaft 4c is erected in the cutout portion. A roller 14 is rotatably supported on the support shaft 4c, and the reversing portion 3a of the flat cable 3 described above is located in an opening 15 between the roller 14 and the side surface of the guide body 4b facing the roller 14 (FIG. 4). Therefore, the distance from the rotation center of the rotor 2 to the outer wall surface of the guide body 4b is the largest in the vicinity of the opening 15 where the roller 14 is supported, and the portion 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. 4A shows a tightened state in which most of the flat cable 3 is wound around the outer peripheral surface of the inner cylindrical portion 7b, and when the rotor 2 is rotated counterclockwise (arrow A direction) from this tightened state. Since the reversing portion 3a of the flat cable 3 moves counterclockwise by a smaller rotation amount than 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 that is about twice as much as these movement amounts is drawn out from the inner cylinder part 7b through the opening 15 to the outer cylinder part 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 cylinder portion 5a and wound around the outer wall surface of the guide body 4b of the holder 4, and finally In addition, most of the flat cable 3 is in a rewound state wound around the outer wall surface of the guide body 4b. 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 moved from the guide body 4b side to the inner peripheral surface side of the cylindrical portion 5a. After being unwound, the rotor 2 is further rotated in the clockwise direction, and as shown in FIG. 4A, the flat cable 3 is wound around the outer peripheral surface of the inner cylinder portion 7b. Become.

  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. 1, the flat cable 3 is once wound around the outer cylinder part 5a located outside the guide body 4b of the holder 4, and the guide body is compared with the circumferential length of the inner peripheral surface of the outer cylinder part 5a. Since the circumferential length of the outer wall surface of 4b is sufficiently short, the required length of the flat cable 3 can be significantly shortened. Moreover, since the uneven part 4g which reduces a contact area with the flat cable 3 was formed in the outer wall surface of the guide body 4b of the holder 4, at the time of the winding tightening operation | movement which the flat cable 3 is drawn | fed out from the outer wall surface of the guide body 4b, 3 is smoothly drawn out without being in close contact with the outer wall surface of the guide body 4b, so that the rotor 2 and the holder 4 can be smoothly rotated. In particular, even when a sliding portion between the stator 1 and the movable member such as the rotor 2 or the holder 4 is filled with a lubricant such as grease and the lubricant oozes to the outer wall surface of the guide body 4b, The flat cable 3 can be smoothly fed out from the outer wall surface of the guide body 4b. In the case of the present embodiment example, the uneven portion 4g is formed excluding a part of the outer wall surface (minimum diameter portion) of the guide body 4b. However, the uneven portion 4g is formed on the entire circumference of the outer wall surface of the guide body 4b. The same uneven part 4g may be formed also on the inner wall surface of the guide body 4b.

Here, the shortening effect of the above-described flat cable 3 will be described with reference to FIG. 5. FIG. 5 (a) shows a conventional type rotary connector in which the flat cable is wound around the outer cylinder portion to be rewound. (B) is a rotary connector according to the present embodiment in which a flat cable is wound around a guide body of a holder to be in a rewind state. In these rotary connectors, the inner diameter of the path of the flat cable (the diameter dimension in the tightened state) ) Is r, the outer diameter of the flat cable path (the diameter dimension in the unwinding state) is R, and the finite rotation speed of the rotor is N, the required length L of the flat cable 3 is (L / rπ) From + (L / 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. In the case of the rotary connector shown in FIG. The diameter R corresponds to the outer diameter of the guide body 4b, which is smaller than the inner diameter of the outer cylinder portion. 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 portion is 50 mm, the inner diameter of the outer cylinder portion is 100 mm, the outer diameter of the guide body is 70 mm, and the finite number of rotations of the rotor is six, Substituting r = 50 mm, R = 100 mm, and N = 6 into the equation results in 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 embodiment, the case where the flat cable 3 is wound around the outer wall surface of the guide body 4b having the outer wall surface eccentric with respect to the cylindrical inner wall surface has been described. In short, the point is that the distance from the rotation center of the rotor 2 to the outer wall surface of the guide body 4b may be set to be maximum in the vicinity of the opening 15 as compared with other portions. For example, as shown in FIGS. 6 and 7, a non-circular guide body 4b composed of an annular portion 4b-1 and a restricting portion 4b-2 is formed, and the flat cable 3 is connected to such a guide body 4b and the roller 14 in an oval shape. If it winds around, the holder 4 can be further reduced in weight. In this case, the annular portion 4b-1 extends in the circumferential direction so as to surround most of the through hole 4d, and the restricting portion 4b-2 extends radially outward from one end of the annular portion 4b-1. Faces the regulating portion 4b-2 through the opening 15.

  Further, the shape and the formation position of the uneven portion 4g formed on the guide body 4b are not limited to the above embodiment example. For example, as shown in FIG. 6, the annular portion 4b-1 is formed in a wave shape to form the uneven portion 4g. As shown in FIG. 7, a large number of cylindrical convex portions are formed on the annular portion 4 b-1 at predetermined intervals to form a concave and convex portion 4 g, or not shown, but on the outer wall surface of the guide body 4 b A large number of hemispherical protrusions can be interspersed to form the uneven part 4g. In short, the uneven part 4g for reducing the contact area with the flat cable 3 is formed on at least the outer wall surface of the guide body 4b. Just do it.

  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. It is a top view which shows the modification of a holder. It is a top view which shows the modification of a holder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator 2 Rotor 3 Flat cable 4 Holder 4a Annular flat plate part 4b Guide body 4b-1 Annular part 4b-2 Restriction part 4c Axle 4d Through hole 4f Cavity part 4g Concavity and convexity part 5 Case 5a Outer cylinder part 6 Cover 6a Bottom plate part 7 Upper rotor 7a Top plate part 7b Inner cylinder part 8 Lower rotor 9 Annular space 14 Roller 15 Opening

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 is provided with a guide body extending so as to surround the inner cylinder portion with the opening as a base end, and the distance from the rotation center of the rotor to the outer wall surface of the guide body is smaller than that of the other portion. A rotary connector that is set to be maximized in the vicinity, and has an uneven portion that reduces a contact area with the flat cable on an outer wall surface of the guide body.   2. The rotary connector according to claim 1, wherein the concavo-convex portion includes concave portions and convex portions that are alternately formed along a circumferential direction of the outer wall surface of the guide body.   3. The guide body according to claim 1, wherein the guide body has an outer wall surface that is eccentric with respect to an inner wall surface that extends concentrically with the inner cylinder portion, and a concave shape between the inner wall surface and the outer wall surface of the guide body. A rotary connector having a cavity formed therein. The holder according to any one of claims 1 to 3, wherein the holder has an annular flat plate portion having an outer diameter substantially the same as an inner diameter of the outer cylinder portion, and the guide body is erected on the annular flat plate portion. Rotating connector characterized by

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