Relay apparatus for relative rotating members

Abstract: A relay apparatus for relative rotating members includes a first rotating member (rotating member) 11 having an internal cylindrical portion 11a, a second rotating member (fixed member) 12 having an external cylindrical portion 12a which surrounds the internal cylindrical portion 11a with a predetermined gap and is relatively rotated with respect to the internal cylindrical portion 11a, a flexible flat cable 13 which is stored along an annular space K between the internal cylindrical portion 11a and the external cylindrical portion 12a to be spirally wound and which has an inner peripheral portion 13a held by the internal cylindrical portion 11a and an outer peripheral portion 13b held by the external cylindrical portion 12a, and a C-shaped moving member 21, movably arranged along the space K, for inverting the flexible flat cable 13 in an opening portion 211c. One rotating member of the first rotating member 11 and the second rotating member 12, which is rotatably driven, has a flange 11b formed on the cylindrical portion, and the moving member 21 is arranged on the flange 11b.

Description: Field of the Invention The present invention relates a relay apparatus for relative rotating members in which electrical connection between relatively rotating members is performed through a cable. Description of the Related Art A conventional relay apparatus for relative rotating members comprises, e.g., a first rotating member having an internal cylindrical portion, a second rotating member having an external cylindrical portion surrounding the internal cylindrical portion with a predetermined gap, a flexible flat cable (to be referred to as a cable hereinafter) which is spirally wound to be stored in an annular space K between the internal cylindrical portion and the external cylindrical portion, and a C-shaped moving member, movably arranged along the space K, for inverting the cable in an opening portion of the C-shaped moving member. The cable has an inner peripheral portion held by the internal cylindrical portion, and has an outer peripheral portion held by the external cylindrical portion. The C-shaped moving member is slidably arranged on a lower cover covering the lower end face of the space K. The second rotating member is integrated with the external cylindrical portion and the lower cover to rotatably support the first rotating member. In the relay apparatus for relative rotating members arranged described above, when the internal cylindrical portion is rotated clockwise with respect to the external cylindrical portion, the cable moves to be wound on the internal cylindrical portion. For this reason, the cable outside the moving member is brought into contact with the outer peripheral surface of the moving member, and is inverted while being in contact with one opening end to be inserted in the moving member. The cable is wound on the internal cylindrical portion. In this case, one opening end of the moving member is pressed by the cable to be rotated clockwise. More specifically, the moving member is slid on the lower cover. When the internal cylindrical portion is rotated counterclockwise with respect to the external cylindrical portion, the cable wound on the internal cylindrical portion is rewound to be moved therearound. For this reason, the cable wound on the internal cylindrical portion is brought into contact with the inner peripheral surface of the moving member, and is inverted while being in contact with another opening end to move outside the moving member. The cable is brought into contact with the inner surface of the external cylindrical portion. In this case, the other opening end of the moving member is pressed by the cable to be rotated counterclockwise. More specifically, the moving member is slid on the lower cover. In the relay apparatus for relative rotating members described above, since the moving member is slid on the lower cover with rotation of the internal cylindrical portion, sliding noise is disadvantageously generated. When the cable is rewound with rotation of the internal cylindrical portion, the cable is brought into contact with the other opening end of the moving member, thereby rotating the moving member. However, since sliding resistance is generated in the moving member, compression stress is generated in the cable as reaction of the sliding resistance. For this reason, the cable is easily buckled. US-A- 5 224 871 discloses a relay apparatus for relative rotating members comprising a first rotatable member having an internal cylindrical portion, a second fixed member having an external cylindrical portion which surrounds the internal cylindrical portion with a predetermined gap wherein the rotatable member is relatively rotatable with respect to the external cylindrical portion, a flexible flat cable which is stored along an annular space between the internal cylindrical portion and the external cylindrical portion and which has an inner peripheral portion held by the internal cylindrical portion and an outer peripheral portion held by the external cylindrical portion, and an elastic member disposed in the annular space and biasing the flexible cable in the radially-inward direction. The elastic member may be composed of a leaf spring formed in a C-shape and is arranged on a flange formed an the external cylindrical portion. SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and has as its objects to provide a relay apparatus for relative rotating members in which sliding noise of a moving member can be reduced, and a flexible flat cable can be prevented from being buckled. In order to achieve the above object, the invention provides a relay apparatus according to claim 1. A preferred embodiment of the invention according to claim 2 is characterized in that the moving member is integrally formed and consists of a resin material, and a dimension in a radial direction of the moving member can be elastically changed by changing a gap between one opening end (211a) and the other opening end (211b) in the opening portion (211c) of the moving member (21). A preferred embodiment of the invention according to claim 3 is characterized in that a bridge portion (213) for connecting the one opening end (211a) and the other opening end (211b) in the opening portion (211c) of the moving member (21) is arranged, and the bridge portion (213) can be flexibly bent by changing the gap between one opening end (211a) and the other opening end (211b). A preferred embodiment of the invention according to claim 4 is characterized in that the moving member (21) has an inner diameter set to be a diameter such that the flexible flat cable (13) wound on the internal cylindrical portion (11a) and externally extended by elastic force is in contact with the moving member (21). A preferred embodiment of the invention according to claim 5 is characterized in that the moving member (21) has an inner diameter set to be slightly larger than the outer diameter of the flexible flat cable (13) wound on the internal cylindrical portion (11a) the maximum number of turns at a high density. A preferred embodiment of the invention according to claim 6 is characterized in that the moving member (21) has an inner diameter set to be a diameter obtained by adding a value six times the thickness of the flexible flat cable (13) to the outer diameter of the internal cylindrical portion (11a). A preferred embodiment of the invention according to claim 7 is characterized in that the moving member (21) has an inner diameter which decreases with time, the lower limit of the inner diameter is set by stopper means (214) arranged in the opening portion (211c), and the minimum inner diameter of the moving member (21) is set to be a diameter obtained by adding the thickness of one flexible flat cable (13) to the outer diameter of the internal cylindrical portion (11a). A preferred embodiment of the invention according to claim 8 is characterized in that the moving member (21) consists of a gliding material In the invention according to claim 1 arranged described above, the first rotatable member is rotatably driven, a flange is formed on the internal cylindrical portion, and the moving member is mounted on the flange. Thus, when the flexible flat cable is rewound from the internal cylindrical portion with rotation of the internal cylindrical portion, the flexible flat cable moves to be extended therearound, and is brought into contact with the inner surface of the moving member. The flexible flat cable is inverted in the opening portion to move outside the moving member. At this time, since the flexible flat cable has an inner peripheral portion held by the internal cylindrical portion, the flexible flat cable rotatably moves by an amount equal to an amount of movement of the internal cylindrical portion. In addition, since the moving member is mounted on the flange, the moving member is to be moved in the same direction as that of the internal cylindrical portion by an amount equal to an amount of movement of the internal cylindrical portion. Therefore, the internal cylindrical portion, the flexible flat cable inside the moving member, and the moving member move in the same direction and by equal amounts. However, since the amount of movement of the inverted portion of the flexible flat cable is smaller than the amount of movement of the moving member or the like, the amount of movement of the moving member is made smaller than the amount of movement of the internal cylindrical portion by the inverted portion of the flexible flat cable. For this reason, the moving member is slid on the flange. An amount of sliding of the moving member is advantageously smaller than that obtained when the moving member is mounted on, e.g., the lower cover of the second fixed member which is not rotatably driven. Therefore, the sliding noise of the moving member can be reduced. When the flexible flat cable is rewound, the flexible flat cable is extended outside to be slid on the inner surface of the moving member. For this reason, compression stress is generated in the flexible flat cable and the flexible flat cable is easily buckled. However, according to claim 2, since the moving member is arranged such that the moving member can be elastically deformed in the radial direction, the externally extending force of the flexible flat cable can be absorbed. Therefore, compression stress generated in the flexible flat cable can be reduced, and the flexible flat cable can be prevented from being buckled. Similarly, the flexible flat cable (13) can be prevented from being buckled. According to claim 3, since the bridge portion (213) is freely bent by a change in gap between one opening end (211a) and the other opening end (211b), the elastic deformation of the moving member (21) in the radial direction is not prevented by the bridge portion (213). Therefore, due to the elastic deformation of the moving member (21) in the radial direction, the flexible flat cable (13) can be prevented from buckled. In addition, when the bridge portion (213) is not arranged, due to contraction of the molded resin material, the gap between one opening end (211a) and the other opening end (211b) may decrease, or one opening end (211a) and the opening end (211b) may be offset from each other in an axial direction. However, since a resin material can be filled in a cavity with good balance by arranging the bridge portion (213), a decrease in the gap between one opening end (211a) and the other opening end (211b) caused by contraction after molding can be prevented. In addition, the offset between one opening end (211a) and the other opening end (211b) in the axial direction can be prevented by the bridge portion (213). More specifically, when the bridge portion (213) is arranged, the molding accuracy of the moving member (21) can be improved. Therefore, the flexible flat cable (13) can be stably guided by the moving member (21). According to claim 4, the flexible flat cable (13) is extended outside the internal cylindrical portion (11a) by elastically extending force of the flexible flat cable (13). Since the inner surface of the moving member (21) is brought into contact with the flexible flat cable (13) which is elastically extended, movement of the moving member (21) in the radial and axial directions can be limited by the flexible flat cable (13). For this reason, the following noise can be prevented. That is, noise is generated when the moving member (21) is brought into contact with, e.g., the external cylindrical portion (12a), or noise is generated when the moving member (21) is brought into contact with the upper and lower covers of the moving member (21). According to claim 5, since the inner diameter of the moving member (21) is set to be slightly larger than the outer diameter of the flexible flat cable (13) wound on the internal cylindrical portion (11a) the maximum number of turns at a high density, the flexible flat cable (13) can be sufficiently wound in the moving member (21) with rotation of the first rotating member (11). The thickness of the flexible flat cable (13) is set to be very small, and an amount of elastic extension of the flexible flat cable (13) from the internal cylindrical portion (11a) is considerably larger than the thickness of the flexible flat cable (13). For this reason, even if one flexible flat cable (13) is wound on the internal cylindrical portion 11a, the flexible flat cable (13) is in elastic contact with the inner surface of the moving member (21). Therefore, as in the invention according to claim 5, noise generated by moving the moving member (21) can be prevented. According to claim 6, since the inner diameter of the moving member (21) is set to be a diameter obtained by adding a dimension six times the thickness of the flexible flat cable (13) to the outer diameter of the internal cylindrical portion (11a), the flexible flat cable (13) having a three-layered thickness can be wound in the moving member (21). In addition, as according to claim 4, noise generated by moving the moving member (21) can be prevented. According to claim 7, the moving member (21) having a dimension which can be elastically changed in the radial direction, and the inner diameter of the moving member (21) is decreased with time. For this reason, the diameter of the moving member (21) does not increase with time. In the future, a state in which the flexible flat cable (13) wound on the internal cylindrical portion (11a) is in contact with the moving member (21) can be kept. Therefore, as in the invention according to claim 5, noise generated by moving the moving member (21) can be prevented, a noise-proof effect can be held in the future. In addition, since the lower limit of the inner diameter is set by the stopper means (214) arranged in the opening portion (211c), the inner diameter of the moving member (21) can be prevented from being excessively small, and an increase in resistance of winding and rewinding the flexible flat cable (13) in the moving member (21) can be prevented. Since the minimum inner diameter of the moving member (21) is set to be a diameter obtained by adding the thickness of one flexible flat cable (13) to the outer diameter of the internal cylindrical portion (11a), at least the first flexible flat cable (13) can be smoothly wound in the moving member (21). When the first flexible flat cable (13) is wound in the moving member (21), other portions of the flexible flat cable (13) can be continuously and smoothly wound in the moving member (21). More specifically, when the second or more flexible flat cables (13) are wound in the moving member (21), the moving member (21) gradually increases in diameter. However, since the flexible flat cable (13) is continuously formed to have a large length, resistance generated by an increase in diameter of the moving member (21) rarely increases. According to claim 9, since the moving member consists of a gliding material, a sliding resistance of the flexible flat cable against the moving member can be reduced. Therefore, compression stress generated in the flexible flat cable can be further reduced, and the flexible flat cable can be prevented from being buckled. In the invention according to claim 1, it is assumed that the internal cylindrical portion (11a) is rotated in a direction in which the flexible flat cable (13) is rewound. In this manner, the flexible flat cable is inserted from the outside of the moving member (21) into the opening portion (211c) and inverted in the opening portion (211c) to be wound on the internal cylindrical portion (11a). In this case, since the moving member (21) is mounted on the flange (11b), the internal cylindrical portion, the flexible flat cable in the moving member, and the moving member move in the same direction by equal amounts. However, since the amount of movement of the inverted portion of the flexible flat cable is smaller than the amount of movement of the moving member or the like, the amount of movement of the moving member is made smaller than the amount of movement of the internal cylindrical portion by the inverted portion of the flexible flat cable. For this reason, the moving member is slid on the flange. An amount of sliding of the moving member is advantageously smaller than that obtained when the moving member is mounted on, e.g., the lower cover of the second rotating member which is not rotatably driven. Therefore, the sliding noise of the moving member can be reduced. In this case, since the flexible flat cable (13) is drawn by the internal cylindrical portion (11a), there is nothing to be afraid of buckling the flexible flat cable. In the invention according to claims 2, 3, 4, 5, 6, 7, or 8, when the internal cylindrical portion (11a) is rotated to rewind the flexible flat cable (13), the flexible flat cable (13) is drawn by the internal cylindrical portion (11a). For this reason, there is nothing to be afraid of buckling the flexible flat cable (13). BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a main part of a relay apparatus for relative rotating members according to the first embodiment of the present invention; FIG. 2 is an exploded perspective view showing a main part of the relay apparatus for relative rotating members in FIG. 1; FIG. 3 is a plan view showing a main part of the relay apparatus for relative rotating members in FIG. 1; FIG. 4 is an exploded perspective view showing the relay apparatus for relative rotating members in FIG. 1; FIG. 5 is a plan view showing the first example of the moving member in the relay apparatus for relative rotating members in FIG. 1; FIG. 6 is a plan view showing the second example of the moving member in the relay apparatus for relative rotating members in FIG. 1; FIG. 7 is a plan view showing the third example of the moving member in the relay apparatus for relative rotating members in FIG. 1; FIG. 8 is a sectional view showing a main part of a relay apparatus for relative rotating members according to the second embodiment of the present invention; FIG. 9 is a plan view showing a main part of a bridge portion of a moving member in the relay apparatus for relative rotating members in FIG. 8; FIG. 10 is a sectional view showing the bridge portion of the moving member in the relay apparatus for relative rotating members and is a view from X in FIG. 9; FIG. 11 is a view showing the first example of the bridge portion of the moving member in the relay apparatus for relative rotating members in FIG. 8, and is a view corresponding to the view from X in FIG. 9; FIG. 12 is a view showing the second example of the bridge portion of the moving member in the relay apparatus for relative rotating members in FIG. 8, and is a view corresponding to the view from X in FIG. 9; FIG. 13 is a view showing the third example of the bridge portion of the moving member in the relay apparatus for relative rotating members in FIG. 8, and is a view corresponding to the view from X in FIG. 9; FIG. 14 is a view showing the fourth example of the bridge portion of the moving member in the relay apparatus for relative rotating members in FIG. 8, and is a view corresponding to the view from X in FIG. 9; FIG. 15 is a view showing the fifth example of the bridge portion of the moving member in the relay apparatus for relative rotating members in FIG. 8, and is a view corresponding to the view from X in FIG. 9; FIG. 16 is a sectional view showing a main part of a relay apparatus for relative rotating members according to the third embodiment of the present invention; FIG. 17 is a sectional view showing a main part of a relay apparatus for relative rotating members according to the fourth embodiment of the present invention; FIG. 18 is a view showing a stopper means of a moving member in the relay apparatus for relative rotating members in FIG. 17; FIG. 19 is a view showing the first example of the stopper means of the moving member in the relay apparatus for relative rotating members in FIG. 17, and is a view corresponding to the view from Y in FIG. 17; FIG. 20 is a view showing the second example of the stopper means of the moving member in the relay apparatus for relative rotating members in FIG. 17, and is a view corresponding to the view from Y in FIG. 17; FIG. 21 is a view showing the third example of the stopper means of the moving member in the relay apparatus for relative rotating members in FIG. 17, and is a view corresponding to the view from Y in FIG. 17; and FIG. 22 is a view showing the fourth example of the stopper means of the moving member in the relay apparatus for relative rotating members in FIG. 17, and is a view corresponding to the view from Y in FIG. 17. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGs. 1 to 22. FIGs. 1 to 4 show the first embodiment, FIG. 5 shows the first example of a moving member in the first embodiment, FIG. 6 shows the second example of the moving member, FIG. 7 shows the third example of the moving member, FIGs. 8 to 10 show the second embodiment, FIG. 11 shows the first example of a bridge portion in the second embodiment, FIG. 12 shows the second example of the bridge portion, FIG. 13 shows the third example of the bridge portion, FIG. 14 shows the fourth example of the bridge portion, FIG. 15 shows the fifth example of the bridge portion, FIG. 16 shows the third embodiment, FIGs. 17 to 18 show the fourth embodiment, FIG. 19 shows the first example of a stopper means in the fourth embodiment, FIG. 20 shows the second example of the stopper means, FIG. 21 shows the third example of the stopper means, and FIG. 22 shows the fourth example of the stopper means. The first embodiment will be described below with reference to FIGs. 1 to 4. A relay apparatus 10 for relative rotating members according to this embodiment comprises, as shown in FIG. 4, a rotatable member (first rotatable member) 11 having an internal cylindrical portion 11a and a flange 11b annularly extending from the internal cylindrical portion 11a, a fixed member 12 having a external cylindrical portion 12a which surrounds the internal cylindrical portion 11a with a predetermined gap, a flexible flat cable 13 which is stored along an annular space K between the internal cylindrical portion 11a and the external cylindrical portion 12a and which has an inner peripheral portion 13a held by the internal cylindrical portion 11a and an outer peripheral portion 13b held by the external cylindrical portion 12a, and a C-shaped moving member 21, movably arranged along the space K, for inverting the flexible flat cable 13 in an opening portion 211a. An annular upper cover 14 for covering the opening portion above the space K is arranged above the internal cylindrical portion 11a. As shown in FIGs. 1 to 3, a lower cover 12b for covering the opening portion under the space K is integrated with the external cylindrical portion 12a. A through hole 12c which rotatably holds the lower portion of the internal cylindrical portion 11a is formed in the lower cover 12b, and an annular recessed portion 12d for rotatably holding the flange 11b is formed in the lower cover 12b. As shown in FIG. 3, the moving member 21 is constituted by a thin C-shaped cylindrical portion 211, and the cable 13 is inverted through one opening end 211a or the other opening end 211b in an opening portion 211c of the cylindrical portion 211. The opening end 211a is constituted by a plate radially extending along the cable 13 inverted in a U-shaped form. The other opening end 211b is constituted by a plate which is radially recessed to be matched with the shape of the top portion of the cable 13 inverted in a U-shaped form. Curved guide plates 212 which have almost the same shapes as those of the opening ends 211a and 211b are arranged on the outer peripheral portion of the cylindrical portion 211 at predetermined intervals. The moving member 21 is integrally formed and consists of a gliding material consisting of a resin material such as teflon or fluorine polymer. The diameter of the moving member 21 in the radial direction can be elastically changed by changing the gap between one opening end 211a and the other opening end 211b in the opening portion 211c. The moving member 21 is designed such that only leg portions 211d formed on the cylindrical portion 211 are brought into contact with the flange 11b. More specifically, the rectangular leg portions 211d which are in slidable contact with the flange 11b are formed on the cylindrical portion 211 at predetermined intervals. The rotating member 11 is connected to, e.g., a steering wheel side of the steering wheel portion of an automobile, and the fixed member 12 is fixed to the steering column side. In the relay apparatus 10 for relative rotating members arranged as described above, referring to FIG. 3, when the internal cylindrical portion 11a rotates clockwise, the cable 13 is rewound from the internal cylindrical portion 11a and moves to be extended therearound while being in contact with the inner surface of the moving member 21. The cable 13 moves outside the moving member 21 while passing through the opening portion 211c of the moving member 21 to be inverted in a U-shaped form, and is brought into contact with the inner surface of the external cylindrical portion 12a. In this case, since the cable 13 is held by the internal cylindrical portion 11a, the cable 13 moves clockwise by an amount equal to an amount of movement of the internal cylindrical portion 11a. Since the moving member 21 is mounted on the flange 11b, the moving member 21 is to be moved clockwise together with the internal cylindrical portion 11a by equal amounts. Therefore, the internal cylindrical portion 11a, the cable 13 in the moving member 21, and the moving member 21 move in the same direction by almost equal amounts. Since an amount of movement of the inverted portion of the cable 13 is smaller than an amount of movement of the moving member 21 or the like, the inverted portion of the cable 13 is brought into contact with one opening end 211a, and the amount of movement of the moving member 21 is made smaller than the amount of movement of the internal cylindrical portion 11a. For this reason, the moving member 21 is slid on the flange 11b. An amount of sliding of the moving member 21 is advantageously smaller than that obtained when the moving member 21 is mounted on the lower cover 12b of the fixed member 12 which is not rotatably driven. Therefore, the sliding noise of the moving member 21 can be reduced. When the cable 13 is rewound, the cable 13 is extended outside to be moved while being in contact with the inner surface of the moving member 21. For this reason, compression stress is generated in the cable 13, and the cable 13 is easily buckled. However, since the moving member 21 is designed such that the moving member 21 can be elastically deformed in the radial direction, the externally extending force of the cable 13 can be absorbed by the moving member 21. Therefore, compression stress generated in the cable 13 can be reduced, and the cable 13 can be prevented from being buckled. In addition, since the moving member 21 consists of a gliding material, the sliding resistance of the cable 13 against the moving member 21 can be reduced. Therefore, compression stress generated in the cable 13 can be further reduced, and the cable 13 can be prevented from being buckled When the internal cylindrical portion 11a is rotated counterclockwise with respect to the external cylindrical portion 12a, the cable 13 moves to be wound on the internal cylindrical portion 11a. For this reason, the cable 13 outside the moving member 21 passes through the opening portion 211c of the moving member 21 while being in contact with the curved guide plates 212 to be inverted in a U-shaped form, and is inserted into the moving member 21 to be wound on the internal cylindrical portion 11a. In this case, the internal cylindrical portion 11a, the cable 13 in the moving member 21, and the moving member 21 move in the same direction by almost equal amounts. However, since the amount of movement of the inverted portion of the cable 13 is smaller than the amount of movement of the moving member 21 or the like, the inverted portion of the cable 13 is brought into contact with the other opening end 211b, the amount of movement of the moving member 21 is made smaller than the amount of movement of the internal cylindrical portion 11a. For this reason, the moving member 21 is slid on the flange 11b. An amount of sliding of the moving member 21 is advantageously smaller than that obtained when the moving member 21 is mounted on the lower cover 12b of the fixed member 12 which is not rotatably driven. Therefore, the sliding noise of the moving member 21 can be reduced. In this case, since the cable 13 is drawn by the internal cylindrical portion 11a, there is nothing to be afraid of buckling the cable 13. As the moving member 21, moving members arranged as shown in FIGs. 5 to 7 may be used. More specifically, in the moving member 21 shown in FIG. 5, no curved guide plates 212 are arranged, a reinforcing rib 211e is arranged for the cylindrical portion 211 and the opening ends 211a and 211b. In the moving member 21 shown in FIG. 6, a plurality of curved guide plates 212 are arranged, and a rib 211e for reinforcing the curved guide plates 212, the cylindrical portion 211, and the opening ends 211a and 211b is arranged. In the moving member 21 shown in FIG. 7, a plurality of gliding portions 211f radially extending are arranged on the inner surface of the cylindrical portion 211. In this moving member 21, the cable 13 is brought into contact with the top portions of the gliding portions 211f. For this reason, the contact area between the cable 13 and the moving member 21 can be decreased. Therefore, since a sliding resistance of the cable 13 with respect to the moving member 21 can be reduced, the above arrangement is effective to reduce sliding noise and to prevent the cable 13 from being buckled. In addition, the gliding portions 211f is also effective to reinforce the cylindrical portion 211. The second embodiment of the present invention will be described below with reference to FIGs. 8 to 10. The same reference numerals as in the first embodiment shown in FIGs. 1 to 4 denote the same parts in the second embodiment, and a description thereof will be omitted. It is a different point between the second embodiment and the first embodiment that a bridge portion 213 is arranged in the opening portion 211c of a moving member 21. More specifically, in the moving member 21, as shown in FIGs. 8 to 10, the bridge portion 213 for connecting one opening end 211a and the other opening end 211b of the moving member 21 is arranged. The bridge portion 213 is designed to be freely bent by changing a gap between one opening end 211a and the other opening end 211b. The bridge portion 213 consists of a resin material such as teflon or fluorine polymer, and is integrated with the moving member 21. The bridge portion 213 is designed such that the bridge portion 213 is bent by rooted hinges 213a and 213b and a central hinge 213c. The rooted hinges 213a and 213b and the central hinge 213c are formed to have small thicknesses such that the bridge portion 213 is bent only when one opening end 211a and the opening end 211b are moved to be separated from each other or close to each other. For this reason, when the opening end 211a and the other opening end 211b are offset from each other in the axial direction, the offset in the axial direction is prevented by the bridge portion 213. In addition, the bridge portion 213, as shown in Fig. 9, is arranged such that the central hinge 213c is inserted into the moving member 21. The bridge portion 213, as shown in FIG. 10, is arranged on one opening end 211a and the other opening end 211b not to prevent movement of the cable 13. In the relay apparatus 10 for relative rotating members arranged as described above, since the bridge portion 213 is freely bent by a change in gap between one opening end 211a and the opening end 211b, elastic deformation of the moving member 21 in the radial direction is not prevented by the bridge portion 213. Therefore, the elastic deformation of the moving member 21 in the radial direction prevents the cable 13 from being buckled. In addition, when no bridge portion 213 is arranged, the gap between one opening end 211a and the other opening end 211b may decrease by contraction of the resin material after molding, or the opening end 211a and the other opening end 211b may be offset from each other in the axial direction. However, since a resin material can be filled in a cavity with good balance by arranging the bridge portion 213, a decrease in the gap between one opening end 211a and the other opening end 211b caused by contraction after molding can be prevented. In addition, the offset between one opening end 211a and the other opening end 211b in the axial direction can be prevented by the bridge portion 213. More specifically, when the bridge portion 213 is arranged, the molding accuracy of the moving member 21 can be improved. Therefore, the cable 13 can be stably guided by the moving member 21. In the second embodiment, the bridge portion 213 is arranged on one opening end 211a and the other opening end 211b. However, as shown in FIG. 11, the bridge portion 213 is arranged such that the upper portions of the opposing portions of one opening end 211a and the other opening end 211b are connected to each other. In addition, the bridge portion 213, as shown in FIG. 12, may extend downward from the flange 11b to prevent the cable 13 from being moved. Furthermore, the bridge portion 213 extending downward, as shown in FIG. 13, may be arranged together with the bridge portion 213 shown in FIG. 10, or, as shown in FIG. 14, may be arranged together with the bridge portion 213 shown in FIG. 11. The bridge portion 213, as shown in FIG. 15, may be arranged such that the central hinge 213c is bent to extend outside the moving member 21. In addition, the bridge portions 213 shown in FIGs. 9 to 15 may be arranged in the moving members 21 shown in FIGs. 5 to 7, respectively. The third embodiment of the present invention will be described below with reference to FIG. 16. The same reference numerals as in the first embodiment shown in FIGs. 1 to 4 denote the same parts in the third embodiment, and a description thereof will be omitted. It is a different point between the third embodiment and the first embodiment that the inner surface of a moving member 21 is in contact with a cable 13. More specifically, as shown in FIG. 16, an inner diameter A of the moving member 21 is set to be a diameter such that the cable 13 wound on the internal cylindrical portion 11a and externally extending by elastic force is brought into contact with the inner surface of the moving member 21. Since FIG. 16 shows a state wherein the cable 13 is wound on the internal cylindrical portion 11a at a high density, the cable 13 is not in contact with the inner surface of the moving member 21. However, the cable 13 extends outside by elastically extending force to be brought into contact with the inner surface of the moving member 21. The inner diameter A of the moving member 21 is set to be a diameter slightly larger than the outer diameter of the cable 13 wound on the outer periphery the maximum number of turns at a high density. More specifically, when the outer diameter of the internal cylindrical portion 11a is represented by B; the thickness of the cable 13, C; and the number of the cables 13 which overlap at a high density in the circumferential direction, X, the inner diameter A is preferably set to satisfy the following conditions: A > (B + C×X) and A ≒ (B + C×X). In the relay apparatus 10 for relative rotating members arranged as described above, since the inner surface of the moving member 21 is brought into contact with the cable 13 elastically extending, movement of the moving member 21 in the radial and axial directions is limited by the cable 13. For this reason, noise generated by bringing the moving member 21 into contact with an external cylindrical portion 12a or noise generated by bringing the moving member 21 into contact with an upper cover 14 (see FIG. 4) or a lower cover 12b (see FIG. 4) can be prevented. When the inner diameter A of the moving member 21 is set to be slightly larger than the outer diameter of the flexible flat cable 13 wound on the outer periphery of the internal cylindrical portion 11a the maximum number of turns at a high density, the cable 13 can be wound in the moving member 21 with a sufficient margin inside the moving member 21 by rotation of the rotating member 11. Since the thickness C of the cable 13 is set to be very small, and an amount of elastic extension of the cable 13 from the internal cylindrical portion 11a is considerably larger than the thickness C. For this reason, even if one cable 13 is wound on the internal cylindrical portion 11a, the cable 13 elastically extends to be brought into contact with the inner surface of the moving member 21. Therefore, noise generated by moving the moving member 21 can be prevented. In the third embodiment, as the moving member 21, the moving member 21 having a diameter which can be elastically changed is used. However, if a moving member 21 having a diameter which cannot be elastically changed is used, movement of the cable 13 into/from the moving member 21 is not prevented. The number X of cables 13 described above is preferably set to be 6. More specifically, the cable 13 is preferably wound on the internal cylindrical portion 11a three times for the following reason. That is, if the cable 13 is wound on the internal cylindrical portion 11a four or more times, the length of the cable 13 is excessively large, and movement of the cable 13 becomes unstable. The fourth embodiment of the present invention will be described below with reference to FIGs. 17 and 18. The same reference numerals as in the third embodiment shown in FIG. 16 denote the same parts in the fourth embodiment, and a description thereof will be omitted. It is a different point between the fourth embodiment and the third embodiment that the diameter of a moving member 21 decreases with time and the a stopper means 214 is arranged in an opening portion 211c. More specifically, the moving member 21, as shown in FIGs. 17 to 18, has an inner diameter A which decreases with time, and the lower limit of the inner diameter A is set by the stopper means 214 arranged in the opening portion 211c. The minimum inner diameter of the moving member 21 is set to be a diameter obtained by adding a thickness C of one cable 13 to an outer diameter B of an internal cylindrical portion 11a. The moving member 21 has the inner diameter A which decreases with time by increasing the thickness of the inner peripheral portion. The stopper means 214 is integrally formed on the moving member 21, and has a stopper rod 214a arranged at one opening end 211a and a stopper projection 214b arranged at the other opening end 211b. When the stopper rod 214a is brought into contact with the stopper projection 214b, a decrease in diameter of the moving member 21 can be stopped. In a relay apparatus 10 for relative rotating members arranged as described above, the moving member 21 having a dimension which can be elastically changed in the radial direction, and the inner diameter A of the moving member 21 decreases with time. For this reason, the inner diameter A of the moving member 21 does not increase with time. In the future, a state in which the cable 13 wound on the internal cylindrical portion 11a is in contact with the moving member 21 can be kept. Therefore, noise generated by moving the moving member 21 can be prevented, a noise-proof effect can be held in the future. In addition, since the lower limit of the inner diameter A is set by the stopper means 214 arranged in the opening portion 211c, the inner diameter A of the moving member 21 can be prevented from being excessively small, and an increase in resistance of winding and rewinding the cable 13 in the moving member 21 can be prevented. Since the minimum inner diameter of the moving member 21 is set to be a diameter obtained by adding the thickness of one cable 13 to the outer diameter of the internal cylindrical portion 11a, at least the first cable 13 can be smoothly wound in the moving member 21. When the first cable 13 is wound in the moving member 21, other portions of the cable 13 can be continuously and smoothly wound in the moving member 21. More specifically, when the second or more flexible flat cables 13 are wound in the moving member 21, the moving member 21, the moving member 21 gradually increases in diameter. However, since the cable 13 is continuously formed to have a large length, resistance generated by an increase in diameter of the moving member 21 rarely increases. The stopper means 214, as shown in FIG. 19, extends from one opening end 21a to the other opening end 21b to be brought into contact with the other opening end 21b, so that the stopper means 214 may be constituted by only the stopper rod 214a for stopping a decrease in the moving member 21. In addition, the stopper means 214, as shown in FIG. 20, may be arranged to project downward from the flange 11b not to prevent movement of the cable 13. However, the stopper means 214 must be constituted by the stopper rod 214a and the stopper projection 214b because the stopper means 214 projects downward. The stopper means 214 extending downward, as shown in FIG. 21, may be arranged together with the stopper means 214 shown in FIG. 18, or, as shown in FIG. 22, may be arranged together with the stopper means 214 shown in FIG. 19. The stopper means 214 may be arranged on the moving member 21, the bridge portion 213 may be arranged under the moving member 21, and the stopper means 214 and the bridge portion 213 may be upside-down. The stopper means shown in FIGs. 17 to 22 may be arranged in the moving members 21 shown in FIGs. 5 to 7, respectively. In each of the first, second, third, and fourth embodiments, the first rotatable member is rotatably driven as the first rotating member 11, and the second member is fixed as the fixed member 12. However, the first rotatable member according to there embodiments may without deviation from the definition of a relay apparatus according to claim 1 be fixed, and the second fixed member may be rotatably driven. In this case, the moving member 21 is inevitably mounted on the flange (lower cover 12b) formed on the second fixed member. In each of the first, second, third, and fourth embodiments, even if no flange 11b on which the moving member 21 is mounted is arranged, buckling of the cable 13 can be prevented by elastic deformation of the moving member 21 in the radial direction.

Claims: A relay apparatus for relative rotating members comprising: a first rotatable member (11) having an internal cylindrical portion (11a); a second fixed member (12) having an external cylindrical portion (12a) which surrounds the internal cylindrical portion (11a) with a predetermined gap and is relatively rotatable with respect to the external wherein the first rotatable member (11) cylindrical portion (12a) ; a flexible flat cable (13) which is stored along an annular space (K) between the internal cylindrical portion (11a) and the external cylindrical portion (12a), and which has an inner peripheral portion (13a) held by the internal cylindrical portion (11a) and an outer peripheral portion (13b) held by the external cylindrical portion (12a); and a C-shaped moving member (21), movably arranged along the space (K), said flexible flat cable (13) being inverted in an opening portion (211a) of said moving member (21) ; wherein the rotatable member (11), which is rotatably driven, has a flange (11b) formed on the cylindrical portion (11a), and said moving member (21) is arranged on the flange (11b). A relay apparatus for relative rotating members according to claim 1, wherein said moving member (21) is integrally formed and consists of a resin material, and a dimension in a radial direction of said moving member (21) can be elastically changed by changing a gap between one opening end (211a) and the other opening end (211b) in the opening portion (211c). A relay apparatus for relative rotating members according to claim 2, wherein a bridge portion (213) for connecting the one opening end (211a) and the other opening end (211b) in the opening portion (211c) of said moving member (21) is arranged, and said bridge portion (213) can be flexibly bent by changing the gap between one opening end (211a) and the other opening end (211b). A relay apparatus for relative rotating members according to claim 1, wherein said moving member (21) has an inner diameter (A) set to be a diameter such that said flexible flat cable (13) wound on the internal cylindrical portion (11a) and externally extended by elastic force is in contact with said moving member (21). A relay apparatus for relative rotating members according to claim 1, wherein said moving member (21) has an inner diameter set to be slightly larger than the outer diameter of said flexible flat cable (13) wound on the internal cylindrical portion (11a) the maximum number of turns at a high density. A relay apparatus for relative rotating members according to claim 1, wherein said moving member (21) has an inner diameter set to be a diameter obtained by adding a value six times the thickness (C) of the flexible flat cable (13) to the outer diameter (B) of the internal cylindrical portion (11a). A relay apparatus for relative rotating members according to claim 2, wherein said moving member (21) has an inner diameter which decreases with time, the lower limit of the inner diameter is set by stopper means (214) arranged in the opening portion (211c), and the minimum inner diameter of said moving member (21) is set to be a diameter obtained by adding the thickness of one flexible flat cable (13) to the outer diameter of the internal cylindrical portion (11a). A relay apparatus for relative rotating members according to claim 1, wherein said moving member (21) consists of a gliding material.

Inventors: ARAI KAZUYA, ISHIKAWA SATOSHI, OKAMOTO HIROYUKI, SAKAI KAZUHITO, SAKAKIBARA TAKESHI, TANAKA HIRAKU, UMEMURA MASAKAZU, ARAI, KAZUYA, ISHIKAWA, SATOSHI, OKAMOTO, HIROYUKI, SAKAI, KAZUHITO, SAKAKIBARA, TAKESHI, TANAKA, HIRAKU, UMEMURA, MASAKAZU, ARAI, KAZUYA, C/O YAZAKI PARTS CO., LTD., ISHIKAWA, SATOSHI, C/O YAZAKI PARTS CO., LTD., OKAMOTO, HIROYUKI, C/O YAZAKI PARTS CO., LTD., SAKAI, KAZUHITO, C/O YAZAKI PARTS CO., LTD., SAKAKIBARA, TAKESHI, C/O YAZAKI PARTS CO., LTD., TANAKA, HIRAKU, C/O YAZAKI PARTS CO., LTD., UMEMURA, MASAKAZU, C/O YAZAKI PARTS CO., LTD.
Applicants: YAZAKI CORP, YAZAKI CORPORATION
Application year: 1996
Main classification: H01R35
IPC codes: B60R16, H01R35