JPH0523341U - Flexible electric circuit body - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a flexible electric circuit body capable of improving bending durability without increasing electric resistance. [Structure] A rotating body 20 (rotor) that reciprocally rotates within a limited rotation range, and a fixed body 3 that houses this rotating body 20.
A flexible electric circuit body 10 for transmitting and receiving an electric signal to and from 0 (housing), which is composed of a flat conductor 11 and an insulating coating layer 12 that insulates and fixes these flat conductors 11 at a neutral position of the rotating body 20. The thickness t ′ of the bent portion 11a of the flat conductor 11 is formed thinner than the thickness t of other portions.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of a flexible electric circuit body used in a brushless electric signal transmission device, and more particularly to a flexible electric circuit body capable of improving bending durability without increasing electric resistance.

[0002]

[Prior Art]

 For example, in an automobile steering device, etc., a rotating body (rotor) that reciprocally rotates within a limited rotation range, a fixed body (housing) that houses this rotating body, and one end thereof is connected to the outer circumference of the rotor, A brushless electric signal transmission device having a flexible electric circuit body for transmitting and receiving electric signals is used, the other end of which is connected to the inner circumference of the housing.

In the brushless electric signal transmission device, for example, when the rotor rotates in one direction in synchronization with the steering of the automobile, the flexible electric circuit body is sent from the inner chamber to the outer chamber in the housing, and the rotor is rotated. Is rotated in the opposite direction to the above, the flexible circuit body is configured to be pulled back from the outer chamber to the inner chamber.

As shown in FIG. 4, the flexible electric circuit body used in the brushless electric signal transmission device has parallel flat conductors 2 having a uniform wall thickness t, and these flat conductors 2 are insulated and fixed. The flexible electric circuit body 1 is usually a ribbon-shaped flat cable, and includes a plurality of flat conductors 2, and various electric conductors are provided according to the conductive pattern of the flexible electric circuit body 1. It is connected to the device.

However, in the conventional brushless electric signal transmission device, since the flexible electric circuit body 1 is bent in a U shape at the take-out portion from the inner chamber to the outer chamber of the housing, the stress related to this bending portion is different. It becomes higher than the part. Not only that, when the steering is in the neutral position, that is, when the steering wheel is in the straight-ahead position where the steering wheel has the largest operating range, the bent portion of the flexible electric circuit body 1 is always located at the outlet from the inner chamber to the outer chamber. As a result, the number of bendings of this bent portion becomes the largest as compared to other portions, so that the bending durability of the bent portion is reduced, and the flexible electric circuit body 1 is easily broken at this bent portion. I was afraid.

The stress σ applied to the bent portion of the flexible electric circuit body is σ = E · t / 2R (where E is the Young's modulus of the flat conductor, t is the thickness of the flat conductor, and R is the radius of curvature). ), It is conceivable to reduce the wall thickness of the flat conductor 2 in order to reduce the stress σ in the bent portion where the bending repetition is concentrated. If the wall thickness is reduced over its entire length, the electrical resistance of the circuit increases, and the transmission accuracy deteriorates.

[0007]

[Problems to be solved by the device]

 The present invention has been achieved as a result of investigations for solving the problems of the above-described conventional flexible electric circuit body.

Therefore, an object of the present invention is to provide a flexible electric circuit body capable of significantly improving bending durability without increasing electric resistance.

[0009]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the flexible electric circuit body of the present invention transmits and receives an electric signal between a rotating body that reciprocates within a limited rotation range and a fixed body that houses the rotating body. A flexible electric circuit body, which comprises a flat conductor and an insulating coating layer that insulates and fixes these flat conductors, and the thickness of the bent portion of the flat conductor at the neutral position of the rotor is It is characterized in that it is formed thinner than the part.

[0010]

[Action]

 In the flexible electric circuit body of the present invention, the bending portion of the flat conductor at the neutral position of the rotating body, that is, the flat conductor has the largest number of times of repeated bending, and the thickness of only the portion where repeated bending is concentrated is different from that of other portions. Since it is made thinner than the wall thickness, the electric resistance of the circuit does not increase, and the stress in the bending part where repeated bending is concentrated can be reduced, and the bending durability can be dramatically improved, and this part will not break. It is possible to eliminate the possibility that

[0011]

【Example】

 Hereinafter, embodiments of the flexible electric circuit body of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective explanatory view of a flexible electric circuit body of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is a cross section of a brushless electric signal transmission device to which the flexible electric circuit body of the present invention is applied. FIG.

In the embodiment shown in FIGS. 1 and 2, a flexible electric circuit body 10 of the present invention comprises a plurality of (three in the drawing) flat conductors 11 and an insulating coating layer 12 for insulating and fixing these flat conductors 11. It consists of

Further, the wall thickness t ′ of the flat conductor 11 ′ located in the portion (hereinafter, simply referred to as “bending portion”) 13 in which the number of repeated bending is most located in the substantially central portion of the flexible electric circuit body 10 is the other The flat conductor 11 is formed thinner than the wall thickness t of the flat conductor 11 so that t> t ′.

Here, for example, the conventional product A having a uniform thickness with the wall thickness t of the flat conductor 11 being = 0.15 mm, the wall thickness t ′ of the flat conductor 11 ′ located at the bent portion 13 is 0.06 mm, In the product B of the present invention in which the thickness t of the flat conductor 11 in the other part is 0.15 mm, comparing the stresses σ applied to the respective bent portions 13, σA = E × 0.15 / 2R in the conventional product A, In the product B of the present invention, σB = E × 0.06 / 2R, so σB = 0.06 / 0.15 · σA = 0.4σA, and the stress applied to the bending portion 13 of the product B of the present invention is 60. %, It is possible to dramatically improve the bending durability of the flat conductor 11 at the bending concentrated portion.

Further, in the flexible electric circuit body of the present invention, the electric resistance of the circuit is not increased by partially reducing the thickness of the flat conductor 11 ′ located at the bent portion 13, so that it is equivalent to the conventional one. It is possible to secure the transmission accuracy of.

The total length of the flexible electric circuit body 10 of the present invention is usually in the range of 600 to 800 mm, and the bent portion 13 of the flexible electric circuit body 10 of the present invention connects the flexible electric circuit body 10 to the brushless electric signal transmission device. When it is applied to the flexible electric circuit body 10, the thinned flat conductor 11 ′ is located at the position corresponding to the extraction part from the inner chamber to the outer chamber where the number of repeated bendings of the flexible circuit body 10 is most concentrated. The length of the bent portion 13 is longer than the length corresponding to 1/2 of the circumference of the roller located at the take-out portion, and is usually set to 90 to 110 mm.

As a means for partially thinning the flat conductor 11 in the bent portion 13, a method of further partially pressing the corresponding portion of the flat conductor 11 pressed to a uniform thickness in a post process. Alternatively, there is a method of cutting the corresponding portion of the flat conductor 11 pressed to a uniform thickness from both sides or one side in a subsequent process, and insulating the both sides of the flat conductor 11 partially thinned in this way. By uniformly coating the coating layer 12, the flexible electric circuit body 10 of the present invention can be obtained.

Next, an embodiment of a brushless electric signal transmission device to which the flexible electric circuit body 10 of the present invention is applied will be described with reference to FIG.

In FIG. 3, 20 is a rotor as a rotating body that rotates in synchronization with a handle shaft (not shown), and 30 is a fixed body that concentrically accommodates a predetermined space between the rotor 20 and the rotor 20. One end of the flexible electric circuit body 10 is connected to the outer periphery of the rotor 20, and the other end of the flexible electric circuit body 10 is connected to the inner peripheral wall of the housing 30.

Further, an intermediate plate 40 is arranged in the housing 30, and the intermediate plate 40 divides the space into an inner chamber 40a and an outer chamber 40b by an outer peripheral wall thereof.

Then, the intermediate plate 40 rotates in the same direction as the rotation direction of the rotor 20 at a reduction ratio according to the gear ratio.

Further, a plurality of guide rollers 41 are provided in the intermediate plate 40, and a take-out portion 42 from the inner chamber 40a to the outer chamber 40b is opened in a part of the outer peripheral wall of the intermediate plate 40. The body 10 is led out to the outer chamber 40b of the intermediate plate 40 in a state of being reversed from the wound state through the outer periphery of any one guide roller 41a in the vicinity of the take-out portion 42.

When the brushless electric signal transmission device having the above-mentioned structure operates, first, the flexible electric circuit body 10 wound around the rotor 20 is loosened by the rotation of the rotor 20 in the unwinding direction, and the guide roller 41a rotates 180 °. The direction is changed to move from the inner chamber 40a to the outer chamber 40b side through the take-out portion 42.

On the contrary, the flexible electric path body 10 moves from the outer chamber 40b to the inner chamber 40a side by the rotation of the rotor 20 in the rewinding direction.

However, when the steering wheel is in the neutral position, that is, when the steering wheel is in the straight-ahead position where the operating range is the largest, the same part of the flexible electric circuit body 10 is always located in the extraction part 42, and the flexible part located in this part. The electric circuit body 10 has a U-shape along the circumference of the guide roller 41a, and becomes the bending portion 13 with the largest number of repeated bendings.

Therefore, in the present invention, as described above, the flat conductor 11 ′ located in the bent portion 13 is formed to be thinner than the other portions, so that stress is reduced and bending durability is improved. It improves the sex.

[0028]

[Effect of the device]

 As described above, according to the flexible electric circuit body of the present invention, the thickness of the bent portion of the flat conductor at the neutral position of the rotating body, that is, the thickness of the flat conductor where the repeated bending is concentrated most and the repeated bending is concentrated is reduced. Since it is made thinner than the wall thickness of other parts, the electric resistance of the circuit is not increased, and the stress in the bending part where bending is concentrated can be reduced, and the bending durability can be dramatically improved. It is possible to eliminate the risk of breakage at this portion.

Therefore, the brushless electric signal transmission device to which the flexible electric circuit body of the present invention is applied can be expected to have excellent transmission accuracy and durability reliability.

[Brief description of drawings]

FIG. 1 is a perspective explanatory view of a flexible electric circuit body of the present invention.

FIG. 2 is a cross-sectional explanatory view taken along the line AA of FIG.

FIG. 3 is a cross-sectional explanatory view of a brushless electric signal transmission device to which the flexible electric circuit body of the present invention is applied.

FIG. 4 is a cross-sectional explanatory view of a conventional flexible electric circuit body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Flexible electric circuit body 11 Flat conductor 12 Insulation coating layer 13 Bending part 20 Rotor (rotating body) 30 Housing (fixed body) 40 Intermediate plate 40a Inner chamber 40b Outer chamber 41 Guide roller 42 Extraction part

Claims (1)

[Scope of utility model registration request] 1. A flexible electric circuit body that transmits and receives an electric signal between a rotating body that reciprocates within a limited rotation range and a fixed body that houses the rotating body, the flexible electric circuit body being flat. A flexible structure comprising a conductor and an insulating coating layer for insulatingly fixing these flat conductors, wherein the thickness of the bent portion of the flat conductor at the neutral position of the rotating body is made thinner than other portions. Circuit body.