JP2005323465A - Rotary connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary connector capable of reducing cost by shortening the required length of a flat cable sharply. <P>SOLUTION: A stator 1 having an outer tubular section 5a is coupled rotatably with a rotor 2 having an inner tubular section 7b, and a holder 4 is arranged rotatably in the annular space 9 defined between the outer tubular section 5a and the inner tubular section 7b. In such a rotary connector, a guide wall 4b having outer circumferential surface eccentric to the inner circumferential surface extending concentrically to the inner tubular section 7b is stood on the annular plate section 4a of the holder 4. An opening 15 for passing the inverted part 3a of the flat cable 3 is provided at the maximum diameter part of the guide wall 4b, a plurality of resilient tongues 16 extending inward of the annular space 9 are supported in cantilever at the outer tubular section 5a, and the flat cable 3 is urged toward the outer circumferential surface of the guide wall 4b by repellence of these resilient tongues 16. <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 band-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 other hand, the flat cable is drawn out from the inner cylinder portion and 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 tube portion or the inner tube portion. 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 reversal part.
Japanese Patent Laying-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 space that is rotatably connected to the stator and defines an annular space between the outer cylindrical portion. A rotor provided with a cylindrical part, and a flat cable which is housed in the annular space in a state where the winding direction is reversed in the middle, and both ends thereof are led out to the outside via the inner cylindrical part and the outer cylindrical part, An annular flat plate portion opposed to the bottom plate portion, and an inner peripheral surface extending concentrically with the inner cylinder portion on the annular flat plate portion. A guide wall having an outer peripheral surface that is eccentric with respect to the guide wall, an opening through which the reverse portion of the flat cable passes is provided in a maximum diameter portion of the guide wall, and an inner space of the annular space is formed in the outer cylinder portion. An elastic tongue piece extending in the direction was provided.

  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 cylindrical portion, the flat cable is first drawn out from the inner cylindrical portion. After being wound around the inner wall of the outer cylinder, the flat cable wound around the inner wall of the outer cylinder is wound around the outer peripheral surface of the guide wall provided on the holder by further rotating the rotor in the same direction. Turned to rewind. On the contrary, when the rotor is rotated in any other direction from the state where the flat cable has been rewound on the outer peripheral surface of the guide wall, the flat cable is first unwound from the guide wall and wound around the inner wall of the outer cylinder portion. After that, by further rotating the rotor in the same direction, the flat cable wound around the inner wall side of the outer cylinder part is wound around the outer wall of the inner cylinder part to be tightened. In other words, the flat cable is temporarily wound around the inner wall of the outer cylinder part in the middle from the tightened state to the rewinded state, but in the rewinded state, the flat cable is wound around the guide wall of the holder disposed in the annular space. Since the total length along the circumferential direction of the outer peripheral surface of this guide wall 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 must be greatly shortened. Can do. In addition, an elastic tongue piece extending inward of the annular space is provided in the outer cylinder portion, and the flat cable is urged toward the outer peripheral surface side of the guide wall by the elastic tongue piece. Even if the vibration in the direction acts, it is possible to suppress the generation of the sound with the backlash by suppressing the swing of the flat cable in the radial direction.

  In the above configuration, the number of the elastic tongue pieces is not particularly limited. However, when a plurality of elastic tongue pieces are arranged at substantially equal intervals along the circumferential direction of the outer cylinder portion, the flat cable is well balanced in the center direction of the annular space. It is preferable because it can be elastically biased.

  Further, in the above configuration, the elastic tongue piece is formed in a curved shape, and when one end portion of the elastic tongue piece is supported in a cantilever shape on the outer cylinder portion, the elastic tongue piece is easily incorporated into the outer cylinder portion. Is preferable.

  The rotary connector of the present invention defines an annular space between the inner cylindrical portion of the rotor and the outer cylindrical portion of the stator, and provides an annular flat plate portion on a holder that is rotatably disposed in the annular space. On this annular flat plate portion, a guide wall having an outer peripheral surface that is eccentric with respect to an inner peripheral surface that extends concentrically with the inner cylindrical portion is erected, and an opening through which the inverted portion of the flat cable passes through the maximum diameter portion of the guide wall Therefore, the flat cable is wound around the outer peripheral surface of the guide wall with a small diameter compared to the outer cylinder part of the stator, and the unwinding state is achieved, and the required length of the flat cable is greatly shortened accordingly. be able to. In addition, an elastic tongue piece extending inward of the annular space is provided on the outer cylinder portion, and the flat cable is urged toward the center of the annular space by the elastic tongue piece, so that the radial direction of the annular space from the outside Even if the vibration is applied to the cable, it is possible to suppress the rocking of the flat cable in the radial direction and reduce the generation of the sound with the backlash.

  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 explanatory view showing the positional relationship between the holder and the elastic tongue piece, and FIG. 5 is an operation explanatory view of the rotary connector.

  As shown in FIGS. 1 to 4, the rotary connector according to the present embodiment includes a stator 1, a rotor 2 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 the bottom plate portion 6a on the stator 1 side, and the top plate portion 7a and the 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 wall 4b and a support shaft 4c erected on the annular flat plate portion 4a, which 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 thereof. The center hole 4d is inserted in 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, hemispherical protrusions 4e are integrally formed at a plurality of locations on the lower surface of the annular flat plate part 4a, and the sliding resistance with the bottom plate part 6a is reduced by these protrusions 4e. On the other hand, the guide wall 4b is erected on the annular flat plate portion 4a so as to surround most of the center hole 4d, and its inner peripheral surface is substantially concentric with the center hole 4d, but the outer peripheral surface is the center hole 4d. It is greatly eccentric. A part of the guide wall 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 wall 4b facing the roller 14 (FIG. 5). Therefore, the distance from the rotation center of the rotor 2 to the outer peripheral surface of the guide wall 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. A concave cavity 4f is formed between the inner circumferential surface and the outer circumferential surface of the guide wall 4b, and the weight of the entire holder 4 is reduced by the cavity 4f.

  Three elastic tongues 16 formed of synthetic resin are supported in a cantilever shape on the outer cylindrical portion 5a of the stator 1 (case 5), and each elastic tongue 16 is inward of the annular space 9. It extends and elastically contacts the flat cable 3. As shown in FIG. 4, a support portion 16a having a hole is formed on one end side of these elastic tongue pieces 16, and the hole of the support portion 16a is press-fitted into a support column formed in the outer cylinder portion 5a. Each elastic tongue piece 16 is supported by the outer cylinder part 5a at equal intervals of about 120 degrees. These elastic tongue pieces 16 are curved with a curvature similar to that of the inner wall of the outer cylindrical portion 5a, and each elastic tongue piece 16 has a resilience in a direction in pressure contact with the outer peripheral surface of the guide wall 4b.

  Next, the operation of the thus-configured rotary connector will be described mainly with reference to FIG. In FIG. 5, the stator 1 and the rotor 2 including the outer cylinder portion 5a and the inner cylinder portion 7b are omitted, and the elastic tongue piece 16 is also omitted for the sake of simplifying the drawing.

  FIG. 5A shows a tightened state in which most of the flat cable 3 is wound around the outer wall of the inner cylindrical portion 7 b, and at this time, each of the elastic tongue pieces 16 not shown is the outer peripheral surface of the guide wall 4 b of the holder 4. Is in pressure contact. When the rotor 2 is rotated in the counterclockwise direction (arrow A direction) from such a tightened state, the reversing portion 3a of the flat cable 3 is moved in the counterclockwise direction by a smaller amount of rotation than the rotor 2, so that this reversing portion 3a. Following this, the roller 14 and the holder 4 also move in the counterclockwise direction, and as shown in FIG. 5 (b), the flat cable 3 approximately twice as much as these movement amounts is fed out from the inner cylinder portion 7b side. It is wound around the inner wall of the outer cylinder part 5a. When the rotor 2 is further rotated in the counterclockwise direction, as shown in FIG. 5C, the flat cable 3 is drawn out from the outer cylinder portion 5a side and wound around the outer peripheral surface of the guide wall 4b of the holder 4, and finally Thus, most of the flat cable 3 is in a rewound state wound around the outer peripheral surface of the guide wall 4b. Each elastic tongue piece 16 (not shown) is elastically deformed with the fixed end side as a fulcrum along with the radial displacement of the flat cable 3, and the flat cable 3 is in the middle of unwinding shown in FIG. At the same time, it is pressed against the inner wall of the outer cylinder portion 5a and is pressed against the outer peripheral surface of the flat cable 3 wound around the guide wall 4b in the unwinding state shown in FIG. Contrary to the above, when the rotor 2 is rotated in the clockwise direction (arrow B direction) from the unwinding state shown in FIG. 5C, the flat cable 3 is drawn out from the guide wall 4b side and the outer cylinder portion 5a. After being wound around the inner wall, the rotor 2 is further rotated in the clockwise direction, so that most of the flat cable 3 is wound around the outer wall of the inner cylindrical portion 7b as shown in FIG. 5 (a). Tightened state. Also in this case, each elastic tongue piece 16 (not shown) is elastically deformed with the fixed end side as a fulcrum in accordance with the displacement of the flat cable 3 in the radial direction.

  Thus, in the rotary connector according to the present embodiment, the flat cable 3 is in the middle of being in the tightened state shown in FIG. 5 (a) or in the unwinded state shown in FIG. 5 (c). As shown in FIG. 1, the flat cable 3 is once wound around the outer cylinder portion 5a located outside the holder 4, and the circumference of the outer peripheral surface of the guide wall 4b is larger than the circumference of the inner wall surface of the outer cylinder portion 5a. Since it is sufficiently short, the required length of the flat cable 3 can be greatly shortened. The outer cylindrical portion 5a of the stator 1 supports a plurality of elastic tongues 16 extending inward of the annular space 9, and the elastic force of these elastic tongues 16 allows the flat cable 3 to be connected to the outer peripheral surface of the guide wall 4b. As a result, the flat cable 3 in the middle of winding or unwinding is uncovered in the annular space 9 even if vibration in the radial direction of the annular space 9 acts on the rotary connector from the outside. It is possible to suppress the movement, and it is possible to reduce the generation of a sound with a roughness due to the swing of the flat cable 3. Moreover, since the three elastic tongue pieces 16 are arranged at equal intervals of about 120 degrees along the circumferential direction of the outer cylinder portion 5a, the flat cable 3 is elastically biased in a balanced manner toward the center of the annular space 9. Can do. Further, the elastic tongue piece 16 is curved to have a curvature approximating the inner wall of the outer cylindrical portion 5a, and a hole of the support portion 16a formed at one end of the elastic tongue piece 16 is press-fitted into a support column formed in the outer cylindrical portion 5a. Thereby, since the elastic tongue piece 16 is supported in a cantilever shape on the outer cylinder portion 5a, the elastic tongue piece 16 can be easily incorporated into the outer cylinder portion 5a.

Here, the shortening effect of the flat cable 3 described above will be described with reference to FIG. 6. FIG. 6 (a) shows a conventional rotary connector in which the flat cable is wound around the outer tube portion to be rewound. (B) is a rotary connector according to the present embodiment in which a flat cable is wound around a guide wall of a holder to be unwound, and in both of these rotary connectors, the inner diameter of the path of the flat cable (diameter dimension in a tightened state) ) Is r, the outer diameter of the path of the flat cable (the diameter dimension in the rewind 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 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. 6 (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 guide wall, 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. 6B 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 inner diameter of the outer cylinder part is 50 mm, the outer diameter of the inner cylinder part is 100 mm, the outer diameter of the guide wall 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 embodiment described above, the case where three elastic tongue pieces 16 are supported on the outer cylinder portion 5a has been described, but it goes without saying that the number of elastic tongue pieces 16 is not limited to this.

  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 perspective view of the holder with which this rotation connector is equipped. It is explanatory drawing which shows the positional relationship of this holder and an elastic tongue piece. 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 wall 4c Support shaft 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 16 Elastic tongue

Claims (3)

A stator having an outer cylindrical portion, a rotor rotatably connected to the stator, and provided with an inner cylindrical portion defining an annular space between the outer cylindrical portion, and a midway in the annular space A flat cable that is housed in a state in which the winding direction is reversed and whose both ends are led out through the inner cylinder part and the outer cylinder part, and a holder that is rotatably arranged in the annular space. ,
The holder is provided with an annular flat plate portion that opposes the bottom plate portion, and a guide wall having an outer peripheral surface that is eccentric with respect to an inner peripheral surface that extends concentrically with the inner tube portion on the annular flat plate portion, A rotation characterized in that an opening through which the inversion portion of the flat cable passes is provided in the maximum diameter portion of the guide wall, and an elastic tongue piece extending inward of the annular space is provided in the outer cylinder portion. connector.   The rotary connector according to claim 1, wherein a plurality of the elastic tongue pieces are provided at substantially equal intervals in the circumferential direction of the outer cylinder portion. 3. The rotary connector according to claim 1, wherein the elastic tongue piece is formed in a curved shape, and one end portion of the elastic tongue piece is supported in a cantilever shape on the outer cylinder portion.

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