CA2083580A1

CA2083580A1 - Shrinkable automotive clamp and protective coating

Info

Publication number: CA2083580A1
Application number: CA002083580A
Authority: CA
Inventors: Changize Sadr
Original assignee: Salflex Polymers Ltd
Current assignee: Salflex Polymers Ltd
Priority date: 1992-11-20
Filing date: 1992-11-23
Publication date: 1994-05-24

Abstract

ABSTRACT OF THE DISCLOSURE
A clamp attaches a blow-molded drive axle seal to an automobile drive axle. The seal has a generally tubular lip that can be inserted over the drive axle. The clamp comprises a band of heat-shrinkable polymer material adapted to surround the circumference of the lip and to clamp the lip to the first member upon heating the band.
A groove around the circumference of the drive axle receives a pressure sensitive adhesive to bond the lip of the drive axle seal to the drive axle in a fluid sealing manner when the lip is clamped to the first member. The clamp may be made integral with the lip of the drive axle seal by making the drive axle seal from said polymer material, with the body of the seal made non heat-shrinkable, and the lip made heat-shrinkable by suitable treatment, e.g. gamma radiation. The heat-shrinkable polymer material is also adapted to completely surround the drive axle seal and to mechanically interlock with the seal upon heating the material. Since the material is capable of withstanding impacts by extraneous matter, it provides a protective coating for the seal. The polymer material and the seal may be formed and interlocked simultaneously in a blow molding process.

Description

BP File No. 6052-0~

2~83~80 , Title: S~INRABL~ AUTOMOTIVE CT.AMP AND PROTECTIVE COATING

FIELD OF THE INV~NTION
This invention relates to automoti~e applications of shrink-wrap polymers. In one preferred embodiment the invention relates to a clamp made of a shrink-wrap polymer for attaching two automotive parts together in a fluid-tight manner. In another embodiment the invention relates to coatings made of a shrink-wrap polymer for protecting automotive parts.

10 BACKGROUND OF 1~ INVENTION :
Front wheel drive automobiles have drive axles ~ connected to the transmission by constant velocity ~oints. ;~
¦ ("CVJ"). The CVJs are highly vulnerable to dirt and water and are therefore protected by bellows type drive axle covers or seals. Each drive axle seal is usually attached to a drive axle by metal screw-type clamps normally referred to as "hose clamps~.
Typically a lip of the drive axle seal is fitted over the drive axle; the hose clamp is placed over the lip, and the clamp is tightened to exert a radially inwardly directed force on the lip, thus clamping the lip to the drive axle.
To achieve the required clamping force to engage the seal with the axle 60 that it will not leak, and to prevent the seal from slipping on the axle, special "heavy-duty" hose clamps are used. Such clamps must provide a sealing force of about 140 Newton-meters (Nm).
These clamps are heavy and costly and it is awkward, cumbersome, and time consuming to insert them on the lip of the seal.
In other automotive applications, e.g. in rack and pinion steering mechanisms, cover type seals are also used, but the clamping forces can be lower since thç
~ bending forces involved are smaller. However even here, .,1 2~83~8~

the expense of providing and installing clamps is substantial.
Automobiles also deteriorate over time as a result of road conditions, driving habits, improper and untimely maintenance, and the like. Automotive member6 or parts must be replaced on a regular basis due to ~normal wear and tear", and some parts are replaced much sooner than anticipated due to premature deterioration or breaXage. Repairing or replacing parts is often costly and time consuming, and so it is desirable to extend the life of automotive parts. One way of achieving this object is to provide an effective barrier between an automotive part and that which causes it to deteriorate.
Plastic automotive covers are frequently used because they provide a flexible cover for moving automotive parts. One such plastic cover, mentioned earlier, is the seal which covers a CVJ and houses a lubricant for the CVJ (sometimes termed a "CVJ boot~
The CVJ boot also protects the CVJ from elevated temperatures from external heat sources, including heat from the automobile's brakes and the road surface. This external heat is usually greater than the heat generated from the drive axle and CVJ within the CVJ boot.
Unfortunately, CVJ boots deteriorate rather quickly because they are exposed to particularly harsh conditions.
At high speeds, the CVJ boot is subject to impacts by extraneous matter ranging in size from sand particles to laxge stones. If the CVJ boot is cracked, then water and salt may enter the boot and the lubricant within may escape, resulting in damage to the CVJ.
It is therefore an object of the invention in one aspect to provide a clamp to fluidly seal a drive axle seal with an axlet which clamp weighs less and is less expensive than the prior art "heavy-duty" hose clamps. In 135 another aspect it is an object of the invention to Idispense, in some applications, with the need for separate mechanical clamps.
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It is a further object of the present invention in another aspect to provide a protective coating for automotive parts such as CVJ boots, rack and pinion steering covers, and the like.
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SUMMARY OF THE INVENTION
) In one aspect, the invention provides a method of clamping an automotive seal to an automotive shaft, -~
comprising: providing a said seal with a lip shaped to fit snugly over said shaft, inserting said lip over said shaft, inserting a band of heat-shrinkable polymer material over said lip, and heating said band for a time sufficient to clamp said lip to said shaft.
~iIn a second aspect, the invention provides a :
method of clamping an automotive seal to an automotive lS shaft, comprising: providing said seal with a lip shaped to fit snugly over said shaft, said seal being of heat~
shrinkable material, inserting said lip over said shaft, ~iand heating said lip for a time sufficient to clamp said ~
lip to said shaft. ; ~;
20In a third aspect, the invention provides in combination, an automotive shaft, a seal having an annular lip extending over and snugly engaging said shaft, and a band of heat-shrinkable polymer material encircling said lip, said band being heat-shrunk to clamp said lip to said shaft.
¦ In a fourth aspect the invention provides in combination, an automotive shaft, a seal having a body and an integral annular lip extending from said body and fitted snugly over said shaft, said seal being of heat-shrinkable material, said lip being heat-shrunk over said shaft and clamping said seal to said shaft.
In a fifth aspect the invention provides a method of protecting an automotive member from damage caused by heat or extraneous matter comprising:
35(1) providing an automotive member;
(2) surrounding the automotive member with a . .

- 20~3 ~8~

layex of heat-shrinkable polymer material having a minimum thickness of 0.1 mm, and being capable of withstanding impacts by the extraneous matter; and . 5 (3) heating the polymer material for a time and at an elevated temperature sufficient to shrink said layer to interlock the polymer material with the automotive member.
In a sixth aspect the invention provides a coating for protecting an automobile member from damage caused by heat or extraneous matter, the coating comprising a layer of heat-shrinkable polymer material having a minimum thickness of 0.1 mm, and being capable of withstanding impacts by the extraneous matter, said polymer material being adapted to surround the automobile member and to interlock therewith upon heating the polymer material.

DES(:RIPTION QF 1~ DRAWINGS
Preferred embodiments of the present invention are described below with reference to the accompanying drawings in which~
Figure l is a perspective view of a drive axle, a drive axle seal and a shrinkable automotive clamp according to a first embodiment of the present invention;
Figure lA is an enlarged cross sectional view of the encircled area of Figure l;
Figure 2 is a side view of two automotive members and a shrinkable automotive clamp.according to a second embodiment of the present invention;
Figures 3a and 3b are perspective views of shrinkable automotive clamps according to a third embodiment of the invention;
Figure 4 i8 a cross sectional view through the drive axle seal of Figure 1 and a coating for protecting 2~33~8~ ~
_ 5 _ the drive axle seal according to another embodiment of the present invention in an unshrunk configuration;
Figure 5 is a cross sectional view of the invention shown in Figure 4 after shrinking the coating;
and Figure 6 is a sectional view of a mold showing a blow molding process to produce a coated automotive ~-mfember according to the present invention.
~ , DESCRIPTIQN OF PRE:FERRE:D EMBODIME:N~S
10Reference is first made to Figures 1 and lA
which show an automobile drive axle 2 connected to a drive axle seal 4. The drive axle 2 is of conventional form, having a cylindrical center shaft 6, a first end 8 which connects, for e.g., to an automobile transmission, and an enlarged or cup-shaped second end 10. The second end lO
has a flat end face 12 and a generally cylindrical outer surface 14. A groove 16 encircles the outer surface 14.
The drive axle seal 4 has the form of a tapered bellows, having corrugations 20 and terminating at its enlarged end in a cylindrical lip 22. Lip 22 is dimensioned to fit snugly over the outer surface 14 at end 10 of the drive axle.
The seal 4 terminates at its smaller end in another cylindrical lip 24 adapted to be placed over another drive axle section (not shown).
As is well known, the seal 4 is formed (normally by a blow molding process) from a plastic material able to withstand flexing, impacts from stones and the like, and relatively high temperatures produced during operation of the automobile.
In the past, lip 22 of seal 4 was clamped over outer surface 14 by a very strong hose clamp, as previously mentioned. Because of the stresses i~volved, high clamping forces, typically 140 Nm, have been required for such clamps.
According to the invention, the seal 4 is held ~, ....
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2083~8~ ~ :

in place by a combination of means. Firstly, pressure or heat sensitive adhesive 26 is provided, in a quantity sufficient to fill the groove 16 and to flow onto the i outer surface 14 to form a T-shape in cross section.
Adhesive 26 bonds the lip 22 of seal 4 to the outer surface 14 in a sealing manner. Suitable adhesives for $ example are provided by Raychem or Shaw Industries under the trade mark "RAYCHEM".
In addition to the adhesive 26, a heat shrinkable clamp 30 is provided. Camp 30 is a continuous circular band of heat-shrinkable plastic, such as polyester plastic or other suitable material adapted to shrink when heat is applied thereto, and to retain the shrunken state when the heat is removed. Preferably the material used for clamp 30 can shrink up to 40% from its original expanded size when heated. In thè embodiment shown in Fiq. 1, the width of clamp 30 is less than that of lip 22, so that the entire clamp 30 overlies lip 22 and does not extend beyond the free edge 32 of the lip 22.
In use, after the adhesive 26 is placed in the groove 16 of the drive axle 2, the lip 22 of the drive axle seal 4 is inserted over both the outer surface 14 and the adhesive 26 as shown in Figs. 1 and lA. Next, the clamp 30 is placed over lip 22 (although this may also be effected before the lip 22 is inserted onto the drive axle 2). The clamp 30 is then heated to contract it around the lip 22. The pressure of the clamp 30 on the lip 22 clamps the drive axle seal 4 to the drive axle in a sealing manner. The pressure also causes the adhesive 26 to bond the interior surface of the lip 22 to the outer surface 14 of the drive axle. 2.
Typically the level of heat applied to provide the required shrinkage is in the range 70 to 150C and for enough time to allow the thermo-plastic to shrink, typically for between 2 and 5 seconds. The temperature and time of heat application depends on several factors, including the type of plastic used and the thickn~ss of ,.

_ 7 - 2~83`~Q : ~

the clamp 30. It will be appreciated that gamma radiation could be applied to produce the required high heat for shrinkage It is also understood that the applied heat should be k~pt below the melting point of the plastic.
A typical material for the clamp 30 may be the polyester material commonly sold by DuPont under its trade mark "Hytrel".
Another type of material for clamp 30 is a line of heat shrinkable tubing sold by Raychem under the trade mark "Thermofit~. The Thermofit tubing is manufactured by first subjecting the tubing material to high-energy radiation to crosslink its molecules. Next, the tubing is heated and pressure is applied to stretch the tubing from its original form into an expanded form. The tubing is then cooled to adopt this expanded form. When the expanded form of Thermofit tubing is subsequently heated to an elevated temperature, the tubing shrinks, or "recovers"l back to or near its original shape (if unrestrained). Upon reheating of the ~'recovered" tubing, the tubing will not change shape (unless mechanical force is used).
Good results have been achieved using a version of Thermofit tubing sold under the trade mark "CRM". Upon heating the expanded form of the CRM tubing at about a temperature of 135C, its diameter shrinks or recovers up to 50% of the expanded diameter. Recovered CRM tubing can operate in temperatures ranging from -55C to +135C, and up to a temperature of +300C for short periods of time.
In some applications, particularly for seals used for automotive constant velocity joint drive axle applications, the lateral forces imposed on the clamp are 80 high (typically up to 140 Nm) that the clamp 30 and adhesive 26 will not themselves be sufficient. In that case, a metal hose clamp may be used. However since the heat-shrinkable clamp 30 will typically supply up to between 60 and 70 Nm of clamping force, the remaining 70 Nm clamping force needed can be supplied by small and , ;,. -:: ., -8 20~8~ ::

inexpensive hose clamps, typically costing far less than those which would otherwise be needed.
For applications where there is less bending force, e.g. seals used for rack and pinion steering in automobiles, additional metal clamps are not normally needed; the heat-shrinkable clamp 30 will in many cases be sufficient. In fact, in some cases it may be possible to omit the adhesive 26 since the clamping force of the clamp 30 alone may be sufficient to provide the required seal.
Reference is next made to Fig. 2, in which primed reference numerals indicate parts corresponding to those of Fig. 1. In Fig. 2 the drive axle 2' is not enlarged, and the clamp 30' is shown as being sufficiently wide to extend beyond the periphery of lip 22l and over the circumferential outer surface 14~ of the drive axle 2', as indicated at 32. This arrangement provides additional clamping of the seal 4' to the drive axle 2' and also helps to prevent dirt and other materials from entering under the edge 34 of the lip 22~.
Figs. 3A and 3B show a third embodiment of the invention. Double primed reference numerals in Figs. 3A
and 3B indicate parts corresponding to those of Figs. 1 and 2.
Fig. 3A shows a drive axle 2" similar to that of 1 25 Fig. 2, with a telescopic joint (not shown) covered by the ¦ seal 4~. The seal 4" is elongated, having a cylindrical central section 40 and two bellows sections 42, 44 one at each end. Each bellows section 42, 44 has at its free end a lip 22" which seals to the drive axle 2 1 30 In the Fig. 3A embodiment, the entire seal 4" is ¦ formed of heat-shrinkable plastic, such as the CRM tubing described above. The seal 4" is provided in an expanded ~ form prior to heating the lips 22~.
¦ In use, after the seal 4" is installed on the 3 35 drive axle 2", the lips 22" are heated to shrink them onto the drive axle. The heating is preferably localized to the area of lips 22", to avoid affecting (ie. shrinking) :: .

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the remainder of the seal 4l~. Suitable apparatus for providing a localized band of heat (or gamma radiation, as mentioned earlier) iB provided for example by Raychem.
Shrinkage of the rest of the seal 4ll should also be avoided during the operating life of ~he automobile.
Hence, the temperatures to which the seal 4~ will be exposed during the automobile's life should be below the shrinking temperature of the seal's material. For example, the CRM tubing discussed above will be suitable for seals sub~ected to automobile operating temperatures below 135C. If an operating temperature of 135C is reached, or surpassed, then overall shrinkage of the tube 4" will take place. Therefore, for extremely hot climates, a seal material with a higher shrinkage temperature may be desirable. An alternative would be to ~; provide an oversize seal and to shrink the entire seal simultaneously with the lips.
~ The clamping force provided by heat-shrinkable ¦ lips 22 can, as mentioned, be substantial (60 to 70 Nm) 20 and may in some cases be sufficient without using additional clamps. However if additional clamps are needed, they can be of much lighter and less costly construction than was previously required.
In the Fig. 3A embodiment, adhesive as shown in 25 Figs. 1 and 2 may also be used if desired.
Fig. 3B shows two seals 4a", 4b" used with a rack and pinion steering mechanism 50 having steering shafts 2a", 2b". Each seal 4a", 4b" has a pair of end lips 22a", 24a", 22b", 24b" and is formed of heat-30 shrinkable material as described in connection with Fig.
3A. The lips 22a", 22b" are subjected to heat to shrink them onto the rack and pinion steering mechanism 50 and onto shafts 2a", 2b", to provide appropriate seals. Since ~; the bending forces exerted on the seals 4a", 4b" will be 35 very low, additional metal clamps will not normally be required in the Fig. 3B arrangement.
;~ The seals 4, 4~, 4l~, and 4a~, 4b~ will normally Z ,.
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2Q83~0 - ~-be blow-molded in conventional fashion prior to being made heat-shrinkable as discussed earlier.
Referring now to Figs. 4 and 5, another embodiment of the present invention is illustrated.
Reference numerals having a prefix ~ are generally used to identify like elements from previously described embodiments. Fig. 4 shows a drive axle seal 104 of a like configuration to seal 4 and having corrugations 120, and lips 122, 124.
A generally tubular layer 130 is provided around the seal 104 as shown in Figure 4. The layer 130 is formed of a heat-shrinkable polymer material which can be similar or identical to that used for clamp 30 to retain a shrunken form when heat is removed as shown in Figure 5.
Preferably~ the polymer material of layer 130 is also soft and very flexible (such as a low modulus polyester) since it must flex during use. Regarding the seal 104, it may be formed of a plastic as described above for Figure 1 or of a rubber modified polypropylene, such as ~PO ~thermo-plastic olefin).
The overall shape of the layer 130 in itsexpanded form approximates that of the seal 104. The layer 130 should be adapted to fit over and surround the seal 104. In the embodiment shown in Figure 4, the circumference of the layer 130 in its expanded form is slightly larger than that of the seal 104. The layer 130 covers the length of the seal 104 between the lips 122, 124 as shown. It will be appreciated that the length of the layer 130 may be slightly more than the length of the seal 104 to ensure that the lips of the seal 104 are completely covered after the layer 130 is shrunk. Any excess shrunk material 130 protruding beyond the ends of the seal 104 may be removed if necessary. Alternately, if desired, the layer 130 may be shorter than the seal 104 to leave the lips 122, 124 exposed for mounting clamps 30 thereon to clamp the seal 104 to drive axles as presented earlier.

11 20~3.38~) Preferably the circumference of the layer 130 ~, adjacent the lip 124 is smaller than that adjacent the lip 122 (as shown in Figure 4) to reduce the amount of ?, material 130 which is used and to produce a better fit '~ 5 after the layer 130 is shrunk tas shown in Figure 5). If 1 too much material 130 is provided, then the shrunken ~ material 130 may not conform to the desired shape and an j excessive number of air pockets or the like will occur between the layer 130 and seal 104, especially at the ~ 10 narrower lip 124.
i, In use, the layer 130 is placed over the seal 104 to surround the seal 104 as required, and the layer 130 is heated (as discussed previously) to shrink the layer 130 around the seal 104 as shown in Figure 5.
Preferably, the layer 130 engages every part of the outer surface of the seal 104 and conforms completely to the corrugations 120. Some air might be trapped between the shrunken layer 130 and the seal 104, but this should be minimized or eliminated for optimum performance of the layer 130.
There is no need for an adhesive between the layer 130 and the seal 104 to prevent the layer 130 from slipping off since a mechanical interlock is achieved due to the irregular circumference of the seal 104.
Furthermore, the clamping force exerted by the shrunken layer 130 on the seal 104 also frictionally engages or interlocks the layer to the seal. It is understood that the clamping force should not be so great so as to deform or greatly distort the seal or automotive member being coated. Although the layer 130 may be used and retained on an automotive member with a constant circumference and smooth outer surface due to such frictional engagement (or by adding an adhesive to said outer surface), it is preferable to achieve a mechanical interlock to minimize or eliminate the chances of the layer dislodging and slipping off the member. Hence, the present invention is best suited for, but is not limited to, use with 208~8n automotive members having irregular circumferences (for example, a CVJ boot).
The layer 130 can take the form of a flexible plastic mesh rather than a continuous tube. The mesh should be used in combination with an automotive part which experiences relatively little flex to avoid separation of the mesh from the part. A suitable part would be a rack and pinion steering boot as shown in Fig.
3, for instance. The mesh could be applied to the boot to give it additional structural reinforcement, or dimensional stability, and to delay or prevent collapse of the boot should it crack or begin to disintegrate.
Since the seal 104 is normally blow-molded as mentioned earlier, a blow-molding process for coating an automotive member with a mesh or layer 130 is briefly described with reference to Figures 6(a) and (b). Figure 6(a) shows an open blow mold, generally indicated by the reference numeral 200, of usual construction having a left portion 203 and a right portion 205 with left and right inside surfaces 207, 209, respectively. The inside surfaces 207, 209 provide the external shape of the automotive member to be produced, such as the seal 104.
The inside surfaces 207, 209 are first lined with the mesh or layer 130 either loosely (as shown ad~acent the right inside surface 209), or the layer can be held in place by suitable means. For example, suction may be applied through passages 211 to have the layer 130 roughly conform to the shape of the automotive member.
After a parison 213 of thermoplastic polymer material is introduced into the mold 200, the mold is closed to pinch the parison 213 as shown in Figure 6(b~. The parison 213 is then blown to expand the thermoplastic material toward the inside surfaces 207, 209 to form the automotive member. The expanding parison 213 engages the layer 130 and causes the layer 130 to mechanically interlock with the automotive member being formed and conform to the ~ ' - 13 - 20~ 80 shape of the member (similar to that shown in Fi~ure 5 for the seal 104 and layer 130).
If desired, the mesh or layer 130 can then be heated to its shrinking temperature to further tighten the mechanical interlock between the seal 104 and mesh 130.
If the parison 213 is hot enough, then the mesh will already have shrunk during the molding process, and no further heat shrinking of the mesh is required. An advantage of molding the mesh and seal together is the resultant space saving to ship or store the coated automotive members.
While an important application of the invention ;~
is in automotive applications, it will be realized ~hat the invention may also be used in other applications where ~-clamped seals or protective coatings are needed.
The above description is intended in an illustrative rather than a restrictive sense and variations to the specific configuration and materials described may be apparent to skilled persons in adapting 120 the present invention to specific applications. Such variations are intended to form part of the present invention insofar as they are within the spirit and scope ~ ~;
of the claims below. -~
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Claims

1. A method of clamping an automotive seal to an automotive shaft, comprising: providing said seal with a lip shaped to fit snugly over said shaft, inserting said lip over said shaft, inserting a band of heat-shrinkable polymer material over said lip, and heating said band for a time sufficient to clamp said lip to said shaft.

2. A method of clamping an automotive seal to an automotive shaft, comprising: providing said seal with a lip shaped to fit snugly over said shaft, said seal being of heat-shrinkable material, inserting said lip over said shaft, and heating said lip for a time sufficient to clamp said lip to said shaft.

3. The method according to claim 1 or 2 and including the step of inserting an adhesive between said lip and said shaft.

4. The method according to claim 1 wherein said band extends beyond said lip and over said shaft, and including the step of shrinking said band over said shaft as well as over said lip.

5. The method according to claim 1 or 2 wherein said shaft is an automotive drive axle.

6. The method according to claim 1 or 2 wherein said shaft is part of an automotive rack and pinion steering mechanism.

7. In combination, an automotive shaft, a seal having an annular lip extending over and snugly engaging said shaft, and a band of heat-shrinkable polymer material encircling said lip, said band being heat-shrunk to clamp said lip to said shaft.

8. In combination, an automotive shaft, a seal having an annular lip extending over and snugly engaging said shaft, said seal being of heat-shrinkable material, said lip being heat-shrunk over said shaft and clamping said seal to said shaft.

9. The combination according to claim 7 or 8 and including an adhesive between said lip and said shaft.

10. The combination according to claim 7 or 8 and including a groove in said shaft beneath said lip, and an adhesive in said groove between said lip and said shaft.

11. The combination according to claim 7 wherein said band extends beyond said lip and over said shaft, said band being heat-shrunk and thereby clamped onto both said shaft and said lip.

12. The combination according to claim 7 or 8 wherein said shaft is an automotive drive axle.

13. The combination according to claim 7 or 8 wherein said shaft is part of an automotive rack and pinion steering mechanism.

14. The combination according to claim 7 or 8 wherein said seal is of a bellows configuration and is blow-molded.

15. A method of clamping a seal to a seal receiving member, comprising: providing said seal with a lip shaped to fit snugly over said member, said seal being of heat-shrinkable material, inserting said lip over said member, and heating said lip for a time sufficient to clamp said lip to said member.

16. In combination, a seal, and a seal receiving member, said seal having an annular lip extending from said body and fitted snugly over said member, said seal being of heat-shrinkable material, said lip being heat-shrunk over said member and clamping said seal to said member.

17. A method of protecting an automotive member from damage caused by extraneous matter comprising:

(1) providing an automotive member;
(2) surrounding the automotive member with a layer of heat-shrinkable polymer material having a minimum thickness of 0.1 mm and being capable of withstanding impacts by the extraneous matter; and (3) heating the polymer material for a time and at an elevated temperature sufficient to shrink seal layer to interlock the polymer material with the automotive member.

18. The method of claim 17 wherein said automotive member has an irregular circumference and said layer mechanically interlocks with the automotive member upon said layer being heated.

19. The method of claim 18 wherein said layer is in the form of a mesh.

20. The method of claim 18 wherein said layer of polymer material is capable of withstanding a temperature of up to 140°C after interlocking.

21. The method of claim 17 or 18 wherein said layer, upon being heated to said elevated temperature, adopts a generally similar profile to that of the automotive member.

22. The method of claim 21 wherein said automotive member has a rippled profile.

23. The method of claim 22 wherein said automotive member is selected from the group comprising a constant velocity joint cover and a rack and pinion steering cover.

24. A coating for protecting an automotive member from damage caused by extraneous matter, the coating comprising a layer of heat-shrinkable polymer material having a minimum thickness of 0.1 mm and being capable of withstanding impacts by the extraneous matter, said polymer material being adapted to surround the automotive member and to interlock therewith upon heating the polymer material.

25. The coating of claim 24 wherein said automotive member has an irregular circumference and said layer mechanically interlocks with said automotive member upon said layer being heated.

26. The coating of claim 25 wherein said layer is in the form of a mesh.

27. The coating of claim 26 wherein said layer of polymer material is capable of withstanding a temperature of up to 140°C after interlocking.

28. The coating of claim 26 wherein said layer, upon being heated, adopts a generally similar profile to that of the automotive member.

29. The coating of claim 28 wherein said automotive member has a rippled profile.

30. The coating of claim 29 wherein the automotive member is selected from the group comprising a constant velocity joint cover and a rack and pinion steering cover.

31. A process for coating an automotive member to protect said member from damage caused by extraneous matter comprising:
(1) positioning at least one layer of heat shrinkable polymer material on the inside surface of a mold, said inside surface having the shape of said automotive member;
(2) introducing a parison of thermoplastic polymer material into the mold, inside said layer of polymer material;
(3) blowing said parison to expand the same towards said inside surface and concurrently therewith causing said parison to engage said layer to mechanically interlock said layer with said parison;
(4) opening the mold and discharging the automotive member.

32. The process of claim 31 wherein, after discharging the member, said layer is heated for a time at an elevated temperature sufficient to shrink said layer to enhance said interlock.

33. The process of claim 31 wherein the temperature of the parison in the mold is sufficient to shrink said layer to enhance said interlock.