Power cable for motor vehicles and a method for bending a power cable for motor vehicles

Abstract

A motor vehicle power cable comprising a flat conductor having an at least rectangular profile, wherein the flat conductor extends along a longitudinal axis, a vertical axis extending along a surface normal of a wide surface of the flat conductor, and a transverse axis extending along a surface normal of a narrow surface of the flat conductor and the flat conductor is bent about the vertical axis and having an inner bend radius and an outer bend radius, characterized in that the flat conductor has at least one forming about the longitudinal axis in the region of the inner bending radius at its inner side edge arranged at the inner bending radius.

Claims

1. Motor vehicle power cable comprising: a flat conductor having a primarily rectangular profile characterized by two wide surfaces opposite each other and two narrow surfaces opposite each other, wherein the flat conductor extends along a longitudinal axis, wherein a vertical axis extends along a surface normal of the wide surfaces of the flat conductor and a transverse axis extends along a surface normal of narrow surfaces of the flat conductor, and the flat conductor is bent about the vertical axis and has an inner bending radius and an outer bending radius, wherein in the region of the inner bending radius at its inner side edge arranged at the inner bending radius, the flat conductor has at least one formed section about the longitudinal axis.

2. Motor vehicle power cable according to claim 1, wherein the extent of the formed section decreases from the inner side edge towards an outer side edge arranged at the outer bending radius.

3. Motor vehicle power cable according to claim 1, wherein the formed section extends along an axis perpendicular to the inner side edge.

4. Motor vehicle power cable according to claim 1, wherein the formed section ends before the outer side edge.

5. Motor vehicle power cable according to claim 1, wherein the formed section is composed of at least two bends about the longitudinal axis which run in opposite directions to one another.

6. Motor vehicle power cable according to claim 1, wherein the formed section is composed of bends about the longitudinal axis which intermittently run in opposite directions to one another.

7. Motor vehicle power cable according to claim 1, wherein the formed section is undulating in a longitudinal section in the region of the inner side edge.

8. Motor vehicle power cable according to claim 1, wherein the flat conductor is metallic, the flat conductor is insulated with an insulating material, and the flat conductor is formed together with the insulating material.

9. Method of bending a motor vehicle power cable comprising: providing a flat conductor having a primarily rectangular profile characterized by two wide surfaces opposite each other and two narrow surfaces opposite each other, wherein the flat conductor extends along a longitudinal axis, wherein a vertical axis extends along a surface normal of the wide surfaces of the flat conductor, and a transverse axis extends along a surface normal of the narrow surfaces of the flat conductor, and the flat conductor is bent about the vertical axis so that the flat conductor has an inner bending radius and an outer bending radius, wherein the flat conductor is bent about the longitudinal axis in the region of the inner bending radius at its inner side edge arranged at the inner bending radius.

10. Method according to claim 9, wherein the flat conductor is first formed and then bent about the vertical axis.

11. Method according to claim 10, wherein the flat conductor is clamped with its opposite wide surfaces between two jaws of a bending tool, a gap between the jaws is reduced and the flat conductor is formed by the jaws, wherein the jaws have interlocking projections and recesses.

12. Method according to claim 10, wherein the flat conductor is formed at its inner side edge about the longitudinal axis and is not formed at its outer side edge along the longitudinal axis.

13. Method according to claim 9, wherein the flat conductor is simultaneously bent about the vertical axis and formed at its inner side edge about the longitudinal axis.

14. Device for bending a flat conductor comprising: two jaws opposing each other, wherein the jaws have tooth-shaped interlocking projections and recesses at their first opposite side edges, and the jaws are movable toward each other to form the flat conductor.

15. Device according to claim 14, wherein the jaws are smooth at their second opposing side edges.

Description

[0044] In the following, the subject matter is explained in more detail with reference to a drawing showing embodiments. In the drawing show:

[0045] FIG. 1a, b a motor vehicle power cable;

[0046] FIG. 2 a motor vehicle power cable bent about the vertical axis;

[0047] FIG. 3a, b forming at the inner side edge of the flat cable;

[0048] FIG. 4 a formed and bent flat cable;

[0049] FIG. 5 clamping jaws of a forming tool;

[0050] FIG. 6 clamping jaws of a forming tool;

[0051] FIG. 7 clamping jaws of a forming tool;

[0052] FIG. 8a-c forming and simultaneous bending by a forming tool;

[0053] FIG. 9a-c clamping jaws of a forming tool;

[0054] FIG. 10a-d forming and simultaneous bending by a forming tool;

[0055] FIG. 11a-c a flat cable during forming and bending according to FIGS. 8a-c and 10a-d, respectively.

[0056] FIG. 1a shows a motor vehicle power cable 2 with a rectangular profile. The motor vehicle power cable 2 is formed of a flat conductor 4 sheathed by an insulating material 6. The motor vehicle power lead 2 has two opposite wide sides 2a and two opposite narrow sides 2b. Further, the motor vehicle power cable 2 has at least one end face 2c. The motor vehicle power cable 2 has a vertical axis 2a′, which is a surface normal on the wide side 2a. The motor vehicle power cable 2 has a transverse axis 2b′, which is a surface normal on the narrow side 2b. Finally, the motor vehicle power cable 2 extends longitudinally along a longitudinal axis 2c′.

[0057] FIG. 1b shows a cross-section of the motor vehicle power cable 2 with the flat conductor 4 as the cable core and the insulation material 6. The perpendicular axes, vertical axis 2a′, transverse axis 2b′ and longitudinal axis 2c′ are also shown. The axes and planes apply equally to the flat conductor 4.

[0058] The motor vehicle power cable 2 (and thus also the flat conductor 4 together or without insulation material 6) is usually bent to fit an installation space in a motor vehicle. All embodiments apply to a motor vehicle power cable 2 or the flat conductor 4 alone.

[0059] Bends about the vertical axis 2a′ can be made, as shown in FIG. 2. The motor vehicle power cable 2 is bent about the vertical axis 2a′ with a bending radius 8 by a bending angle 10. Through this bending about the vertical axis 2a′, an inner bending radius 8a and an outer bending radius 8b are formed. In FIG. 2, it can be seen that the inner bending radius 8a is considerably smaller than the outer bending radius 8b.

[0060] An inner side edge 12a spans the inner bending radius 8a and an outer side edge 12b spans the outer bending radius 8b. Naturally, the length of the arc at the inner bending radius 8a is shorter than the length of the arc at the outer bending radius. However, this also means that the material of both the flat conductor 4 and the insulation 6 is compressed in the region of the inner bending radius 8a and stretched in the region of the outer bending radius 8b. The compression is particularly problematic, as it leads to material hardening and thus to low elasticity and, if applicable, is more sensitive to temperature fluctuations.

[0061] To account for the different length of the circular arcs, it is proposed to form the power cable 2 around the longitudinal axis 2c at the inner bending radius 8a in the area of the inner side edge 12a. The forming results in a forming of the inner side edge 12a in the direction of the vertical axis 2a′. A correspondingly formed inner side edge 12a is shown in FIG. 3a.

[0062] FIG. 3a shows a view of the narrow surface 2b. It can be seen that the course in the region of a forming 14 is wave-shaped, with the inner side edge 12a being formed in the direction of the vertical axis 2a′, with this forming taking place about the longitudinal axis 2c′. It can be seen that the forming 14 is composed of wave troughs 14a and wave crests 14b, which follow each other. In particular, the forming 14 has intermittent wave troughs 14a and wave crests 14b that are deflected antiparallel to each other, parallel to the vertical axis 2a′.

[0063] In FIG. 3b, a perspective view of the forming 14 is shown. It can be seen that starting from the inner side edge 12a towards the outer side edge 12b, the forming 14 becomes smaller. In particular, the outer side edge 12b is not formed. In particular, the forming 14 maximally extends to a center axis 2d on the wide surface 2a. Due to the undulating course, the length of the inner side edge 12a is greater than the length of the outer side edge 12b in a formed state. This serves to compensate for the different lengths of the inner side edge 12a and the outer side edge 12b in a bent state, as described in FIG. 2.

[0064] As a result of the forming 14, the inner side edge 12a is elongated, as shown in FIG. 4b, so that even when bent about the vertical axis 2a′, the compression in the region of the inner side edge 12a of the material of both the flat conductor 4 and the insulation material 6 is reduced.

[0065] The forming 14 can be introduced into the cable 2 by means of clamping jaws as shown in FIG. 5. In FIG. 5, two clamping jaws 20a, 20b are shown folded apart, with their surfaces joining each other shown. The first clamping jaw 20a may have a projection 22a′ in the region of a bend. This projection 22a′ can be seen in the sectional view shown on the right. Corresponding to this projection 22a′, the second clamping jaw 20b may have a recess 22b′. If the two surfaces 20a, 20b are moved towards each other and the cable 2 lies between them, the projection 22a′ presses the cable 2 in the direction of the vertical axis 2a′ and thus bends the latter about its longitudinal axis 2c′ and introduces the forming 14.

[0066] FIG. 6 shows two further clamping jaws 20a, 20b, wherein three projections 22a′, 22a″ are provided on the first clamping jaw 20a in the region of the inner side edge. The two projections 22a′ surround the projection 22a″. The projections 22a′ have a smaller extension both in the direction of the transverse axis 2b′ and in the direction of the vertical axis 2a′. Correspondingly, the second clamping jaw 20b has recesses 22b′, 22b″ that are complementary to the projections 22a′, 22a″.

[0067] FIG. 7 shows the projections 22a′, 22a″ and recesses 22b′, 22b″ in a side view. It can be seen that the projections 22a′, a″ are complementary to the recesses 22b′, b″. The clamping jaws 20a, 20b can be moved relative to each other in the direction 24 towards each other and clamp the cable 2. During this clamping, the forming 14 is introduced into the cable 2.

[0068] As shown in FIGS. 8a-c, it is also possible for the clamping jaw 20a to be moved in a rolling motion over the clamping jaw 20b and thus, while the forming 14 is being introduced, the power cable 2 is directly formed, as shown in FIG. 4.

[0069] In this process, the clamping jaw 20a is moved in the longitudinal direction of the cable 2 starting from a first projection 22a′, as shown in FIG. 8a, over a projection 22a″ to a projection 22a′, as shown in FIG. 8c, over the clamping jaw 20b, wherein a respective projection 22a′, 22a″ comes into engagement with a recess 22b′, 22b″.

[0070] This projection 22a′ can be seen in the sectional view shown on the right. Corresponding to this projection 22a′, the second clamping jaw 20b may have a recess 22b′. If the two surfaces 20a, 20b are moved towards each other and the cable 2 is located therebetween, the projection 22a′ presses the cable 2 in the direction of the vertical axis 2a′ and thus bends the latter about its longitudinal axis 2c′ and introduces the forming 14.

[0071] The forming 14 can be introduced into the cable 2 by means of clamping jaws as shown in FIG. 9a, b. In FIG. 9a, b, two clamping jaws 20a, 20b are shown folded apart, with the surfaces abutting each other in the assembled state. The first and second clamping jaws 20a, b may each have pins 26 in the region of a front edge which are angularly spaced from one another. The pins 26 are pivotally arranged at an axis 28 perpendicular to the drawing plane. The axis 28 lies in a plane parallel to the plane spanned by the longitudinal axis 2c′ and the transverse axis 2b′. Correspondingly mounted pins 26 can be arranged on the clamping jaw 20b in the spaces between the pins 26 of the clamping jaw 20a. A flat cable 2 can be clamped between the clamping jaws 20a, b and a counter bearing 30.

[0072] FIG. 9c shows a sectional view through the jaws 20a, 20b. As can be seen, a pin 26 is pivotally mounted about an axis 28. The pin 26 is pressed down by a drive 32a. The same applies to a pin 26 of the lower jaw 20b with a drive 32b. The drives 32a, b perform a pendulum motion so that the pins are pressed successively against the flat conductor 2 at angular intervals.

[0073] FIGS. 10a-d show the pins 26 in action. The clamping jaws 20a,b are placed onto each other. A groove 32 between the clamping jaws is formed to receive the flat cable 2. The flat cable 2 is inserted into the groove 32 with a narrow side edge 2b and is held in the groove 32 by the counter bearing 30. Then, the pins 26 are pressed onto the flat conductor 2 in the direction of movement 34. In the process, the pins 26 are moved successively one after the other, in an undulating motion toward the flat conductor 2, as can be seen in the sequence of FIGS. 10a-d. This sequence of movements of FIGS. 10a-d can be repeated several times in succession, so that the flat conductor 2 is formed.

[0074] The cable 2 in FIG. 11a corresponds to the cable 2 when it has been bent according to FIG. 8a. The cable 2 in FIG. 11b corresponds to the cable 2 when it has been bent according to FIG. 8b. The cable 2 in FIG. 11 corresponds to the cable 2 when it has been bent according to FIG. 8c. The cable 2 in FIG. 11c also corresponds to the cable 2 if it has been bent according to FIGS. 10a-d, in particular if the pins 26 have been pressed once or multiple times against the cable 2 oscillating manner.

[0075] The arrangement described makes it possible to bend a cable 2 without having to wrap it around a mandrel. The compression of the material of the insulation material 6 as well as of the flat conductor 4 is reduced in the area of the inner bending radius 8a by the extension of the inner side edge 12a.

LIST OF REFERENCE SIGNS

[0076] 2 motor vehicle power cable [0077] 2a wide surface [0078] 2b narrow surface [0079] 2a′ vertical axis [0080] 2b′ transverse axis [0081] 2c′ longitudinal axis [0082] 4 flat conductor [0083] 6 insulation material [0084] 8 bending radius [0085] 8a inner bending radius [0086] 8b outer bending radius [0087] 10 bending angle [0088] 12a inner side edge [0089] 12b outer side edge [0090] 14 forming [0091] 20a,b clamping jaw [0092] 22a′,a″ projection [0093] 22b′,b″ recess [0094] 24 direction of motion [0095] 26 pin [0096] 28 axis [0097] 32 groove [0098] 34 direction of motion