DE10054714A1 - Sealing cable into/onto cable leadthrough channel involves spraying an especially elastomeric sealing element, applying mold, injecting hollow volume with harder plastic material - Google Patents

Abstract

The method involves sealing a cable (2) or cable set passed through a channel(s) (3) to output from the leadthrough element (1) by spraying an especially elastomeric sealing element (7) on the cable outlet opening and cable in a first spraying process, applying an external mold, injecting the resulting hollow volume with a harder plastic material thereby compressed to form a sealing element, forming out the casing element (12) after setting. Independent claims are also included for the following: a cable leadthrough element and uses of the element as a plug gripper, a piezoactuator foot and an ignition plug.

Description

The invention relates to a method for sealing a cable or Cable set on / in a cable entry element with the others Features of the preamble of claim 1 and a Cable entry element with the further features of the preamble of Claim 14.

A cable or a cable set penetrates in a cable entry element (consisting of several cables) at least one cable duct and is in it recorded. The cable enters in the area of at least one cable outlet opening or the cable set out of the cable entry element and leads from there z. B. to a power source. The cable entry element can in particular with the area opposite the cable outlet opening and the wire or cable ends lying there z. B. connected to a plug become.

In the field of diesel injection technology in motor vehicles, it is also known control the valves by means of piezo elements. The piezo elements, also called So-called piezo actuators are held in an actuator base. The Actuator foot consists essentially of a metal part and an overmolded part. The cables for the piezo element run through the metal part. It is tightness of the cables or wires in the actuator base of a few bar is required. Around to achieve this tightness, it is known that in the region of the ends of the Cable ducts rubber parts are used, which are injection molded with polyamide become. The polyamide presses these conical rubber parts into the conical Bore so that a certain tightness is established. Such a thing  The process is time-consuming and cumbersome since it can only be carried out manually. In addition, the required tightness is not achieved in the long term.

The invention has for its object a method with the features of To develop the preamble of claim 1 such that with an automated Process high tightness of the cable entry elements in a relative wide temperature range can be achieved. The invention is also the Task based on a cable entry element with the features of The preamble of claim 14 form such that the Cable bushing element the cables or cable set guided therein safely seals outside.

This object is achieved through the entire teaching of claims 1 and 14 solved. Advantageous further developments of the method result from the Subclaims 2-13. Advantageous variants of the Cable entry elements are taught in claims 15-24. Appropriate uses of the cable entry element result from the claims 25-27.

The inventive method is characterized in that in a first Injection molding a sealing element made in particular of permanently elastic plastic, in particular an elastomer, on the area of the cable outlet opening is sprayed on, a section emerging from the cable duct Cable or cable set is encapsulated. The next step is on the area of the cable outlet opening placed on an outer shape such that between the inner wall of the outer shape and the surface of the sealing element a cavity is formed. This is done in a second spraying process Cavity with a harder compared to the material of the sealing element Plastic material is sprayed out in such a way that the one during the spraying process Inner molding forming sealing element is compressed sustainably. After  Solidification of the jacket element formed by the harder plastic this finally shaped. Using this method, a seal can be made the cable or the cable set in the cable entry element of approx. 30 bar can be achieved. The procedure is automatic by means of a suitable one Injection molding machines can be carried out quickly and reproducibly. The harder Plastic material that forms the casing element can be, for example Trade polyamide, which at pressures between 400 and 800 bar on the Sealing element is sprayed on, so that the elastomer already during the spraying process is put under extreme pressure and the elements to be sealed with the required pressure can be applied or sealed. In which Permanently elastic plastic can be, for example, polybutyl acrylate (PBA) or butatiene styrene rubber (PBS). The plastics are suitable due to their elastic properties, in a wide Temperature range to ensure high tightness.

To create a durable connection between the sealing element and the The cable outlet opening can be made in the area of the cable outlet opening at least one undercut may be arranged during the first injection process is injected with the permanently elastic plastic material. Instead of one An undercut can also be an internal thread or the like with the permanently elastic plastic can be injected. By the subsequent Translating the jacket element is by the compression of the Elastomeric material also in the undercut or the internal thread or the like achieved a high seal. The cable entry element can especially in the area of cable ducts made of metal, in particular steel consist. To increase the connection between the metal Cable outlet opening and the elastomer can also be an adhesive be applied.  

In order to further increase the tightness in the area of the cables, at least a recess extending into the cable grommet z. B. in Area of the cable channels can be provided, which with the permanently elastic plastic material is also ejected.

In order to also seal the cables in the cable ducts and fix them in place, the respective cable duct at least during the first spraying process be injected in sections with the permanently elastic plastic material. The cable ducts can expediently be of stepped or partially conical design be, so that the permanently elastic plastic is safe even in the channels extends into, fills and seals. The sealing of the wires or their insulation in the channels means that they no longer vibrate can, so that no damage to the cable even when vibrations occur are brought about, which may lead to a short circuit could. In addition, vibrations could fatigue the wire material as a result of the wire breaking. Through permanent fixation of the wire this can be prevented by the sealing material. Advantageously, the Cable duct with the sealing material up to the area of the plug contact be sprayed out, so that the sealing and fixing of the cables over their entire length to the free ends of the wires (in the area of the Connector contact) is guaranteed.

A collar-like can be attached to the sealing element in the area of the cable exit point Injection molded element that can serve as cable protection or kink protection. In particular, the collar-like element is part of the sealing element and will also produced during the first spraying process. This is particularly beneficial collar-like element in a recess of the outer shape (for the second Spraying process). In the second spraying process, this becomes collar-like Element compressed from the outside under radially inward pressure, see above that also in the area of the collar-like element an excellent seal  comes about. Another advantage is that the cable insulation in the second spraying process not with the mostly high-melting one Plastic material of the jacket element (e.g. polyamide) come into contact and this could possibly melt. When finished Cable entry element is the collar-like element of the Sheath element only on its circumference, but not on the end, so that the kink protection is also retained thanks to an elastic hold. The collar-like element therefore fulfills several advantageous functions both the production as well as in the finished cable entry element.

The cable insulation of the cable or of the cable set can advantageously be provided the spraying of the sealing element in an inner region of the sealing element to be stripped. This is advantageous because between the wire and the Cable insulation can be leaks. It could e.g. B. Hydrocarbons have diffused, which lead to leaks can. The stripped cable is in the finished part Sealing element embedded and in this way reliable, permanent and absolute tightly insulated.

To also ensure a secure connection between the jacket element and the To produce cable entry element can be at least one hook-like Element and / or at least one undercut on the Cable entry element can be provided, which in the second spraying process be encapsulated. The hook-like element and the undercut can for example over the entire circumference of the cable entry element run and thus on all sides for a secure reception of the jacket element contribute.  

To further increase the tightness, it can be provided that the harder plastic jacket element formed during the curing process further compression of the sealing element expands.

To prevent the sealing element from melting too much during the second spraying process and thereby prevent a change in the elastic properties the sealing element is subjected to a cooling process before the second injection process become. Advantageously, the cooling process in the Sealing element introduced cooling energy should be such that the temperature in the interior of the sealing element during the second spraying process far below the melting temperature of the permanently elastic plastic. The surface of the elastomer core, the subsequent temperature increase to approx. Endure 300 ° C during the second spraying process. It can then become instant Mergers only come in the surface area of the two plastics, which is also desirable in terms of an intimate connection of the two plastics is.

Before the second spraying process, the sealing element can also be used emerging wire sections or cable sections a cooling process be subjected. This prevents the by the to the Cable sections created outer shape derived in the second spraying process Amount of heat would melt the cable insulation. Besides, will thereby transferring the heat over the wire sections in the Prevents interior of the sealing material, which may result in a Melting would result in the core of the sealing element.

The cable entry element according to the invention has at least one Cable channel on, at least one cable or cable set the at least one Cable duct passes through and in the area of at least one cable outlet opening the cable entry element emerges. In the field of  Cable outlet opening is in particular form-fitting with the material of the Cable entry element connected to a sealing element arranged that made of permanently elastic plastic and that by a sprayed Sheath element kept permanently under radially inward pressure becomes. The cable bushing element according to the invention is characterized by very much high tightness in the area of the cable outlet openings, which also Temperature fluctuations as well as vibrations occurring for the whole The duration of use is retained. The special embodiments of the invention will refer to the description above for the sealing process of the Cable entry element referenced.

The cable entry element according to the invention can be versatile for different areas of application can be used. The Cable entry element can e.g. B. can be used as a plug handle. in the In the field of automotive valve technology, the cable entry element can be used as Piezo actuator base can be used, with high tightness of approx. 30 bar required and in the manner described above by means of the sealing element and of the jacket element arranged above can be realized. It is also possible, that the cable entry element is used as a spark plug connector. In addition, there are of course other ways of using the Cable entry element conceivable.

The invention is based on an advantageous embodiment in the Drawing figure explained in more detail. This shows a schematic Process sequence of the method for sealing a cable set on / in a Grommet.

Reference number 1 designates the cable entry element in its entirety. The cable bushing element 1 is not shown completely, in particular the area of the plug contact 21 is not shown. In the cable entry element 1 there is a cable set consisting of two cables 2 , each of which penetrates a cable duct 3 . As shown in step I, the cables 2 emerge from the cable lead-through element 1 in the region of the cable outlet opening 4 . In process step II, the cables 2 are stripped in the later inner region of the sealing element, so that the free wires 5 are directly surrounded by the sealing element which is later injected.

Then, in step III, an outer shape 6 for the first spraying process is placed on the cable entry element 1 . In step IV, a sealing element 7 made of, in particular, permanently elastic plastic, in particular an elastomer, is sprayed onto the outer mold 6 and onto the area of the cable outlet opening 4 , the sections of the cable 2 emerging from the cable ducts 3 and the wires 5 being extrusion-coated. After a short cooling phase and the shaping from the outer mold 6 , in step IV an outer mold 8 is placed on the area of the cable outlet opening 4 such that a cavity 11 is formed between the inner wall 9 of the outer mold 8 and the surface 10 of the sealing element 7 . In the subsequent second injection process, the cavity 11 is injected with a relatively harder material for the sealing element 7 of plastic material such that the inner shape of the body forming the sealing member 7 is permanently compressed during the injection process. Finally, the jacket element 12 formed by the harder plastic is formed from the outer shape 8 after it has solidified. The molded and sealed cable entry element 1 is shown in step VI.

In order to permanently connect the sealing element 7 to the cable lead-through element 1 , an undercut 13 is arranged in the region of the cable outlet opening, which is sprayed out with the permanently elastic plastic material during the first injection process. The undercut is formed as a circumferential groove in the cable lead-through element 1 , which is usually made of metal (e.g. steel), which ensures secure fastening of the sealing element 7 over the entire circumference. Alternatively or additionally, an adhesion promoter can be applied between the cable outlet opening 4 and the outer shape 6 .

In addition, recesses 14 extending into the cable bushing element are arranged in the region of the cable channels 3 and are sprayed out with the permanently elastic plastic material during the first spraying process. This embodiment variant increases the tightness at the interface between the cable outlet opening 4 and the metal part of the cable bushing element 1 .

As can also be seen from the drawing figures, the cable channels 3 are sprayed out in the first spraying process into the area of the plug contact 18 , so that the cables 2 and the wires 5 are also securely sealed in the cable channels 3 and therefore no longer vibrate due to mechanical influences can. Vibration could result in cable stripping or wire break. For spraying out the cable ducts 3 , they are advantageously of stepped or partially conical design, so that the elastomer melt can spread better.

A collar-like element 15 is molded onto the sealing element 7 in the region of the cable exit points. In the flowchart shown, the collar-like element 15 is part of the sealing element 7 and is simultaneously formed by a correspondingly shaped outer shape 6 during the production of the sealing element 7 .

According to step V, the collar-like element 15 engages in a recess 19 in the outer shape 8 . The jacket element 12 sprayed thereon thus surrounds the collar-like element 15 on the edge side, but not on the end side. On the one hand, this means that the high tightness is achieved in the area of the cable exit points as in the area of the cable exit openings 4 . On the other hand, the second spraying process prevents the insulation of the cables 2 from being damaged or even melted due to excessive heat from the higher melting plastic of the jacket element 12 . In addition, the collar-like element 15 serves as kink protection for the protruding cables 2 .

In the second injection process (cf. step V), the harder plastic encapsulates a hook-like element 16 and an undercut 17 , which are arranged on the cable entry element 1 . As a result, the jacket element 12 is also securely connected to the cable bushing element 1 , both the hook-like element 16 and the undercut 17 being expediently provided around the entire circumference of the cable bushing element 1 .

The plastic of the casing element 12 is designed such that the casing element 12 expands during the curing process with further compression of the sealing element 7 and thus an even higher tightness can be achieved.

Before the second spraying process (before step V), the sealing element 7 can also be subjected to a cooling process, so that excessive melting or damage to the mostly low-melting elastic plastic material is prevented by the hot plastic material of the jacket element 12 sprayed thereon. The cooling energy introduced into the sealing element 7 by the cooling process is dimensioned such that the temperature in the interior of the sealing element 7 during the second spraying process is far below the melting temperature of the permanently elastic plastic. In order to also prevent melting inside the sealing element 7 by the wires 5 possibly heated by the spraying process, the cable sections emerging from the sealing element 7 can also be subjected to a cooling process before the second spraying process. The cooling process of the cable sections also prevents damage to the insulation of the cable sections, which is also made of plastic, due to excessive heat input.

The fully formed, sealed cable lead-through element 1 (see step VI) has cable channels 3 , each of which is penetrated by a cable 2 . In the area of the cable outlet opening 4 , the cables 2 emerge from the cable entry element 1 . In the area of the cable outlet opening 4 , a sealing element 7 , which consists of permanently elastic plastic and is held in a lasting manner under radially inward pressure by a sprayed-on jacket element 12, is arranged in a form-fitting manner and connected to the material of the cable entry element 1 . This creates a high level of tightness in the area of the cable outlet opening 4 , which reliably protects the cables 2 or wires 5 guided therein from external influences (e.g. mechanical, thermal or chemical influencing factors).

The cable entry element 1 can, for. B. can be used as a conventional plug handle. A particularly advantageous use of the cable lead-through element 1 is a piezo actuator foot, which is used to control the injection valves, particularly in diesel injection technology. The control lines for the piezo element run through the piezo actuator foot. A prerequisite for correct control of the piezo elements is a high degree of tightness of the control lines in the piezo actuator foot, which is produced by the method according to the invention.

In the field of automotive technology, it is also possible that Cable entry element according to the invention as a spark plug connector train.  

LIST OF REFERENCE NUMBERS

1

Grommet

2

electric wire

3

Cabel Canal

4

Cable outlet opening

5

wire

6

external form

7

sealing element

8th

external form

9

Inner wall (the outer shape)

10

Surface (of the sealing element)

11

cavity

12

jacket element

13

undercut

14

recess

15

collar-like element

16

hook-like element

17

undercut

18

Area of the plug contact

19

recess

Claims (27)

1. A method for sealing a cable or cable set on / in a cable entry element, wherein the cable or cable set passes through at least one cable duct and exits the cable entry element in the area of at least one cable outlet opening, characterized by the following method steps:

• a) spraying a sealing element in a first spraying process, in particular of permanently elastic plastic, in particular an elastomer, onto the area of the cable outlet opening, a section of the cable or cable set emerging from the cable duct being overmolded;
• b) placing an outer shape on the area of the cable outlet opening such that a cavity is formed between the inner wall of the outer shape and the surface of the sealing element;
• c) injection molding of the cavity in a second injection process with a plastic material that is harder than the material of the sealing element in such a way that the sealing element forming an inner molded body is sustainably compressed during the injection process;
• d) shaping the jacket element formed by the harder plastic after it has solidified.

2. The method according to claim 1, characterized in that at least one undercut in the area of the cable outlet opening is arranged, the permanently elastic with the first spraying process Plastic material is injected. 3. The method according to any one of claims 1 or 2, characterized in that at least one reaching into the cable entry element Recess in the first spraying process with the permanently elastic Plastic material is injected. 4. The method according to any one of the preceding claims, characterized in that the at least one cable duct at least during the first spraying process sprayed in sections with the permanently elastic plastic material becomes.   5. The method according to claim 4, characterized in that the cable duct in the area of the first spraying process Connector contact is sprayed out. 6. The method according to any one of the preceding claims, characterized in that to the sealing element in the area of the cable exit points a collar-like Element is injected. 7. The method according to any one of the preceding claims, characterized in that the collar-like element engages in a recess in the outer shape   8. The method according to any one of the preceding claims, characterized in that the cable or the cable set in an inner region of the sealing element is stripped. 9. The method according to any one of the preceding claims, characterized in that in the second injection process due to the harder plastic at least one hook-like element and / or at least one undercut on the Cable entry element are encapsulated. 10. Use of a metallic cable entry element, characterized in that the jacket element formed by the harder plastic Hardening process with further compression of the sealing element expands.   11. The method according to any one of the preceding claims, characterized in that before the second spraying process, the sealing element undergoes a cooling process is subjected. 12. The method according to any one of the preceding claims, characterized in that the cooling energy introduced into the sealing element by the cooling process is dimensioned such that the temperature in the interior of the Sealing element in the second spraying process far below the Melting temperature of the permanently elastic plastic is. 13. The method according to any one of the preceding claims, characterized in that before the second spraying process, also those from the sealing element emerging wire sections or cable sections a cooling process be subjected.   14. Cable entry element ( 1 ) with at least one cable duct ( 3 ), at least one cable ( 2 ) or cable set passing through the at least one cable duct ( 3 ) and emerging from the cable duct element ( 1 ) in the region of at least one cable outlet opening ( 4 ), characterized in that That in the area of the cable outlet opening ( 4 ), in particular in a form-fitting manner with the material of the cable entry element ( 1 ), a sealing element ( 7 ) is arranged, which consists of permanently elastic plastic and which is sustainably held by a sprayed-on jacket element ( 12 ) under radially inward pressure becomes. 15. Cable entry element according to claim 14, characterized in that the sprayed-on jacket element ( 12 ) consists of a comparatively harder plastic material than the material of the sealing element ( 7 ). 16. Cable entry element according to one of claims 14 or 15, characterized in that in the region of the cable outlet opening ( 4 ) at least one undercut ( 13 ) is arranged, which is filled with the permanently elastic plastic. 17. Cable bushing element according to one of claims 14-16, characterized in that at least one in the cable bushing element ( 1 ) extending recess ( 14 ) is provided, which is filled with the permanently elastic plastic. 18. Cable entry element according to one of claims 14-17, characterized in that the cable duct ( 3 ) is at least partially filled with the permanently elastic plastic material. 19. Cable entry element according to claim 18, characterized in that the cable duct ( 3 ) is filled up in the region of the plug contact ( 18 ) with the permanently elastic plastic material around the cable ( 2 ) or around the cable set. 20. Cable entry element according to one of claims 14-19, characterized in that a collar-like element ( 15 ) is provided on the sealing element ( 7 ) in the region of the cable exit point. 21. Cable entry element according to claim 20, characterized in that the collar-like element ( 15 ) is part of the sealing element ( 7 ). 22. Cable bushing element according to one of claims 14-21, characterized in that the cable ( 2 ) or the cable set is stripped in an inner region of the sealing element ( 7 ). 23. Cable entry element according to one of claims 14-22, characterized in that at least one hook-like element ( 16 ) and / or at least one undercut ( 17 ) is provided, which is encapsulated by the harder plastic material. 24. Cable entry element according to one of claims 14-23, characterized in that the sealing element ( 7 ) and the sprayed-on jacket element ( 12 ) are welded on their surface areas. 25. Use of the cable entry element according to one of the Claims 14-24 as a plug handle. 26. Use of the cable entry element according to one of the Claims 14-24 as a piezo actuator foot. 27. Use of the cable entry element according to one of the Claims 14-24 as a spark plug connector.