Flexible conductor element with length compensation section

Abstract

Flexible conductor element with several electrical conductors (12, 14, 16) arranged parallel to one another, and a plastic sheath (20), wherein the electrical conductors (12, 14, 16) are electrically insulated from each other and from the environment by the plastic sheath (20), such that the electrical conductors (12, 14, 16) and the plastic sheath (20) form a flat ribbon cable, wherein the electrical conductors (12, 14, 16) and the plastic sheath (20) have a common length compensation section (34) which has a sawtooth shape, wherein a plastic tube (36) which contracts radially under the influence of heat is provided, which radially surrounds the length compensation section (34), wherein the plastic tube (36) fixes the length compensation section (34) in the longitudinal direction in the contracted state, such that the plastic tube (36) shrinks from a predefined temperature,nestles against the length compensation section (34) and fixes the length of the length compensation section (34).

Description

[0001] The invention is based on a flexible conductor element with a plurality of electrical conductors arranged parallel to one another and a plastic sheath, wherein the electrical conductors are electrically insulated from one another and from the environment by the plastic sheath, wherein the electrical conductors and the plastic sheath have a common length compensation section.

[0002] Such flexible conductor elements, in which several electrical conductors are arranged parallel to one another within a plastic sheath, are well known and are used, for example, to connect sensors, actuators, control units, and other applications in a motor vehicle. When installing the flexible conductor elements, the conductor element is usually cut roughly to the required length in advance, or a flexible conductor element with a length that approximately corresponds to the required length is selected. The distance between two components to be connected by the flexible conductor element can vary due to tolerances; the flexible conductor element has a length compensation section to compensate for the tolerance-related deviation in the distance between the two components to be connected.A conductor element with a length compensation section is disclosed, for example, in DE 11 2010 005 431 T5 and WO 2013 / 180 836 A1. Furthermore, a conductor element with a heat-shrinkable tube is known from US 2012 / 0150 249 A1, from JP 2019-46 778 A, and from JP 2013-201 796 A, wherein JP 2013-201 796 A further discloses that two loops of the conductor element are arranged one above the other and are jointly surrounded by a heat-shrinkable tube. US 5 118 907 A discloses a cable with a heat-shrinkable tube, wherein two loops of the cable are arranged one above the other and are surrounded by a heat-shrinkable tube.

[0003] The problem with this type of tolerance-compensating conductor element is that when the conductor element is installed, the length compensation section causes the conductor element to elongate and sag. This sagging conductor element complicates the assembly of additional components because it sags into an unintended area. Furthermore, a sagging conductor element poses the risk of the conductor element becoming trapped between two components during assembly, resulting in damage. Furthermore, a sagging conductor element can rest on an adjacent component, in which case shrinkage stress on the conductor element could cause abrasion of the plastic sheath and / or breakage of the conductor element.

[0004] To prevent the flexible ladder element from sagging, the flexible ladder elements are secured, for example, with several cable clamps. However, this type of securing of the ladder element leads to increased effort during assembly, as the flexible ladder element must be manually secured by a worker at several difficult-to-access locations.

[0005] The object of the invention is therefore to provide a flexible conductor element which avoids the disadvantages listed above in a simple and cost-effective manner.

[0006] This object is achieved according to the invention by a flexible conductor element according to claim 1.

[0007] The electrical conductors and the plastic sheath form a ribbon cable. Such ribbon cables exhibit relatively high flexibility due to their relatively flat design, with the electrical conductors arranged side by side in a single plane.

[0008] By providing a plastic tube that contracts radially under the influence of heat and radially surrounds the length compensation section. When contracted, the plastic tube fixes the length compensation section longitudinally. This prevents the flexible conductor element from sagging in the assembled state in a simple and cost-effective manner. This reliably prevents damage to the flexible conductor element due to pinching between two components or damage to the plastic sheath due to abrasion caused by contact with an adjacent component. Furthermore, the assembly of other components adjacent to the flexible conductor element can be simplified.

[0009] The length compensation section has a sawtooth-shaped profile. This sawtooth profile creates a spring-like effect, whereby the sawtooth profile is pulled apart when the distance between the two components connected by the flexible conductor element increases. Likewise, the sawtooth profile is compressed longitudinally when the distance between the two components decreases. After the components are connected using the flexible conductor element, the plastic tube is heated, causing it to contract radially and conform to the sawtooth profile. This fixes the length compensation section longitudinally, particularly through positive and frictional engagement.

[0010] The plastic tubing is a so-called shrink tubing, which is usually made of a thermoplastic and contracts radially when exposed to heat, for example, from a hot air gun. The function of the shrink tubing is such that the extruded shrink tubing expands when warm and remains in this expanded state even after cooling. When the plastic tubing is reheated, the shrink tubing contracts back to its original shape. In other words, the shrink tubing "remembers" its original shape, acquired during the initial forming process in the extrusion process, and largely recovers, fitting tightly or tightly to the object being shrunk, depending on its surface shape.

[0011] By shrinking the plastic tubing onto the length compensation section, the length compensation section is fixed in the longitudinal direction of the flexible conductor element. The shrunken plastic tubing conforms to the shape of the length compensation section present at the time of shrinking, creating a positive and / or non-positive connection in the radial and longitudinal directions between the plastic tubing and the length-adjustable section.

[0012] The plastic hose is positioned on the length-adjustable section prior to the installation of the flexible conductor element and completely surrounds it radially. After the electrical connection of two components using the flexible conductor element, the conductor element is held in the desired position and the plastic hose is heated. At a predefined temperature, the plastic hose shrinks, conforms to the length-adjusting section, and fixes the length of the length-adjusting section.

[0013] Preferably, the plastic hose deforms irreversibly when contracted. This ensures reliable fixation of the flexible conductor element in its longitudinal direction.

[0014] In a preferred embodiment, the plastic hose is made of a thermoplastic, in particular polyolefin or polyvinyl chloride. This allows the plastic hose to be manufactured simply and cost-effectively, and the longitudinal fixation of the length-compensating section can be ensured by contracting the plastic hose.

[0015] The plastic hose preferably has a hot-melt adhesive on its inner circumferential surface. When the plastic hose is contracted, the hot-melt adhesive bonds to the length compensation section under heat, creating an additional adhesive bond between the plastic hose and the length compensation section, thereby improving the fixation of the length compensation section in its longitudinal direction.

[0016] Preferably, a fastening device made of a radially contracting plastic is provided, wherein a rigidly arranged fastening element engages in the fastening device and the plastic conforms to the fastening element due to the introduction of heat. The fastening device can, for example, be a pocket provided on the plastic tube, into which a fastening element with a mushroom shape engages, wherein the fastening element is, for example, fastened to a housing. As the plastic tube contracts, the pocket also contracts due to the introduction of heat, whereby the plastic material forming the pocket conforms to the mushroom-shaped fastening element. As a result, the flexible conductor element is fastened to a rigidly arranged component. Alternatively, the fastening device can also be provided on a second plastic tube.

[0017] The flexible conductor element according to the invention can prevent sagging of the flexible conductor element in the assembled state in a simple and cost-effective manner, whereby damage to the flexible conductor element can be reliably prevented and the assembly of other adjacent components can be simplified.

[0018] An embodiment of the invention is explained in more detail with reference to the drawings. The Fig. 1 shows schematically a flexible conductor element in a plan view, the Fig. 2a shows a first embodiment of the flexible conductor element from Fig. 1 in a longitudinal section, and the Fig. 2b a second embodiment of the flexible conductor element from Fig. 1 in a longitudinal section.

[0019] In the Fig. 1 shows a flexible conductor element 10, which is designed as a so-called multi-core ribbon cable. The flexible conductor element 10 has three electrical conductors 12, 14, 16, which are arranged parallel to one another and in a common plane. The flexible conductor element 10 also has a plastic sheath 20 in which the electrical conductors 12, 14, 16 are embedded. By embedding the electrical conductors 12, 14, 16 in the plastic sheath 20, the electrical conductors 12, 14, 16 are electrically insulated from one another and from the environment.

[0020] The flexibility of the conductor element 10 is achieved by, on the one hand, the electrical conductors 12, 14, 16 having a relatively small diameter and thus being able to be deformed with minimal force. On the other hand, the plastic sheath 20 has a relatively thin wall thickness.

[0021] At each of the two longitudinal ends of the flexible conductor element 10, a plug connector 22, 24 is provided, via which the flexible conductor element 10 can be connected to a component to be connected to one another and not shown in the figures.

[0022] During assembly of the components to be connected by means of the conductor element 10, the components shift due to tolerances, whereby the distance between the components changes. Such a tolerance-related shift of the components and thus an increase or reduction of the distance leads to the conductor element 10 being too long or too short. With an increased distance between the components and thus too short a conductor element 10, a coupling between the components would no longer be possible. With a reduced distance and thus too long a conductor element 10, the flexible conductor element 10 would possibly sag in an undesirable area. To prevent this problem, the flexible conductor element 10 has a length compensation section 30, 34. The length compensation section 30, 34 can have a Fig. 2a or one in the Fig. 2b shown configuration can be implemented.

[0023] In Fig. Figure 2a shows a first embodiment of a length compensation section 30, not according to the invention. The length compensation section 30 has a meandering shape, i.e., the length compensation section 30 has at least two mutually opposing 180° deflections. If the distance between the components is reduced or increased due to tolerances, both loops of the length compensation section 30 can lengthen or shorten, thereby shortening or lengthening the overall length of the conductor element 10.

[0024] In Fig. Figure 2b shows a second embodiment of a length compensation section 34. The length compensation section 34 has a sawtooth-like profile. If the distance between the components is reduced or increased due to tolerances, the teeth of the sawtooth-like length compensation section 34 can be pulled apart or pushed together, thereby shortening or lengthening the overall length of the conductor element 10.

[0025] A plastic tube 32, 36 is provided in the area of ​​the length compensation section 30, 34. The plastic tube 32, 36 is designed as a so-called shrink tube.

[0026] In the Fig. In the embodiment of the length compensation section 30 shown in Figure 2a with an S-shaped profile, the plastic hose 32 completely surrounds the length compensation section 30 radially and conforms to the outer contour of the length compensation section 30. In its original state, the plastic hose 32 has a cylindrical profile, whereby the loops of the length compensation section 30 arranged within the plastic hose 32 can move freely and can be changed in the longitudinal direction by pulling on one end of the conductor element. By heating the plastic hose 32, it contracts radially and conforms to the outer contour of the length compensation section 30.As a result, the length compensation section 30 is pressed together and the opposing regions of the S-shaped length compensation section 30 are pressed against one another, whereby such friction is created between these regions that the length compensation section 30 is fixed in the longitudinal direction.

[0027] In the Fig. In the configuration of the length compensation section 34 shown in Figure 2b, the plastic hose 36 has a cylindrical shape in its original state and, when heated, conforms to the sawtooth shape of the length compensation section 34. Due to the sawtooth shape of the length compensation section 34, the contracted plastic hose 36 fixes the length compensation section 34 in a form-fitting manner in the longitudinal direction.

[0028] Additionally, a pocket-shaped fastening device 40 is provided on the plastic tube 32, 36, which cooperates with a mushroom-shaped projection provided on a rigid component. By contracting the plastic tube 32, 36, the plastic tube 32, 36, i.e., the fastening device 40, conforms to the projection, thereby securing the conductor element 10 to the rigidly arranged component.

[0029] The flexible conductor element 10 according to the invention can be used to prevent sagging of the flexible conductor element 10 in the assembled state in a simple and cost-effective manner, while reliably preventing damage to the flexible conductor element 10 caused by pinching between two components or damage to the plastic sheath 20 caused by abrasion from contact with an adjacent component. Furthermore, the risk of the conductor element interfering with the assembly of another component is reduced.

Claims

[1] Flexible conductor element with a plurality of electrical conductors (12, 14, 16) arranged parallel to one another and with a plastic sheath (20), wherein the electrical conductors (12, 14, 16) are electrically insulated from one another and from the environment by the plastic sheath (20), such that the electrical conductors (12, 14, 16) and the plastic sheath (20) form a ribbon cable, wherein the electrical conductors (12, 14, 16) and the plastic sheath (20) have a common length compensation section (34) which has a sawtooth-shaped course, wherein a plastic tube (36) which contracts radially under the influence of heat is present and radially surrounds the length compensation section (34), wherein the plastic tube (36) in the contracted state fixes the length compensation section (34) in the longitudinal direction, such that the plastic tube (36) shrinks from a predefined temperature,nestles against the length compensation section (34) and fixes the length of the length compensation section (34)., [2] Flexible conductor element according to one of the preceding claims, characterized by that the plastic hose (36) is irreversibly deformed when contracted. [3] Flexible conductor element according to claim 1 or 2, characterized by that the plastic hose (36) is made of a thermoplastic material. [4] Flexible conductor element according to one of the preceding claims, characterized by that the plastic hose (36) has a hot melt adhesive on its inner peripheral surface. [5] Flexible conductor element according to one of the preceding claims, characterized bythat a fastening device (40) made of a radially contracting plastic is provided, wherein a rigidly arranged fastening element engages in the fastening device (40) and the plastic of the fastening device (40) nestles against the fastening element by means of heat input.

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