GB2201473A

GB2201473A - Seals

Info

Publication number: GB2201473A
Application number: GB08801124A
Authority: GB
Inventors: Juichi Tanaka; Hideki Agari; Hidehiko Murata; Shinkichi Yamashita
Original assignee: Nihon Radiator Co Ltd; Nitto Electric Industrial Co Ltd
Current assignee: Nitto Denko Corp; Marelli Corp
Priority date: 1987-01-19
Filing date: 1988-01-19
Publication date: 1988-09-01
Anticipated expiration: 2008-01-19
Also published as: DE3801330A1; JPS63180771A; GB2201473B; GB8801124D0

Description

1 9 t SEALS 1 - 5.

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(""-' 0 14 7 -3 A Z- The present invention relates to a seal suitable, for example, for joints between units in an air conditioning apparatus for an automobile.

- A typical air conditioning apparatus for an automobile comprises,, as shown in Figure 6, an intake unit 101 for receiving air, inside and outside compartments into which the air is to be blown, a cooler unit 102 housing therein an evaporator (not shown) for cooling air passing therethrough, and a heater unit 103 for adjusting the temperature of-air cooled by the cooler unit 102 to distribute air into the compartments. Such units 101, 102 and 103 as described above are separately formed. These units 101,, 102 and 103 are connected,-when they are mounted in a vehicle body, to form an air passage therein._ Accordinglyr seal packings 104 are interposed between flanges Fo which form joints to prevent an air leakage. The seal packing 104 is peripherally annually attached to a mating-surface of the respective abutting flange portions Fo-(in Figure 6, , on the side of the cooler unit 102). When the units are connected, the flange portions Fo, Fo are pressed together to press the seal packing-104, thus maintaining the air tightness of the air passage, The conventional seal packing 104 has a square in section, as shown in Figure 4. This seal packing is -formed by cutting foamed urethane or the like into square-sectioned lengths, the bottom surface thereof then having-one surface of a double- sided adhesive tape 105 attached thereto. The other surface of the double- 2 10.

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sided adhesive tape 105 is stuck to the mating surface of the flange portion Fo shown in Figure 6. (Refer to Japanese Unexamined Utility Model Publication No. 46,,413/1985).

However, the aforesaid seal packing made of opencell foamed urethane has a cut surface 107 formed by the cutting operation which has pores resulting from the foam-forming. When water is absorbed into the pores, micro-organisms may multiply therein so producing odour.

The cooling unit 102 on which the seal packing 104 is mounted is disposed below an instrument panel 106 of the vehicle body as shown in Figure 6. This mounting often has to be affixed to the body only after the intake unit 101 and the heater unit 103 have been so mounted. This involves a number of inconveniences; for example, air conditioning apparatus for an automobile initially not provided with a cooler unit 102 will sometimes have the unit installed later. In such a case, the intake unit 101 and the heater unit 103, which have been already mounted on the vehicle body, are moved away from each other, and the cooler unit 102 is then inserted between them below the instrument panel 106. At that time, the seal packings 104 attached to the flange portions Fo of the units tend to peel away to create a clearance in the joint between the units, as a consequence of which the air-tightness of the air passage-fails to be maintained.

In order to overcome the inconveniences noted above, a known seal packing104a having a cross section as shown in Figure 5 (A) has been developed (Refer to Japanese Unexamined Patent Publication No. 137,672/1985 and Japanese Unexamined Patent Publication No. - 2- h 1 3 t 1 1 T 236,729/1985).- To produce a sealing material in the form of the sealpacking 104a, a-strip or length of foamed urethane material or the like having a rectangular section is formed into a sheet on a backing paper, the backing paper is peeled off, and 5.

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longitudinally-extending yarn 108 is mounted to a central portion of one surface of the strip which is then bent as shown in Figure 5(B). The bent surface is bonded by double-sided adhesive tape 109, thereby maintaining a semi-circular section as shown in Figure 10. 5 (A); subsequently, a separate double-sided adhesive tape 105 is stuck to the bottom thereof. In this finished seal packing 104a, the cut surface 107 (which -has pores formed during the foam-forming) is concealed by the tape 105, and only the relatively smooth skin layer-119 is exposed to the outside; thust water resistanceis enhanced. Moreover, the seal packing 104a has a semi-circular sectional shape without being angled, and therefore even when the cooler unit 102 is inserted between the intake unit 101 and the heater 20. unit 103 as previously mentioned, the cooler unit 102 can be smoothly inserted. As a result, the seal packing 104a tends not to peel off,, and the position of the packing is less likely to move as the unit is inserted.

- However, where the seal packing 104a is formed of an open-cell foamed material such as the aforementioned foamed urethane, even if the skin layer 110 is relatively smooth, it still has fine pores therein through which water or the like-may entert possibly resulting in water leakage or odour. Furthermore, even where-the packing is formed of a foam rubber material, the manufacture of the packing 104a requires the steps 30.

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of peeling off a backing paper after a skin layer has been formed on the body and bending it so that a section thereof is formed into a semicylindrical shape. This is a cumbersome operation which increases the cost of manufacture.

It is a primary object of the present invention to provide a seal packing having excellent air tightness and water resistance while at least alleviating the disadvantages noted above with respect to the prior art.

It is a second object of the'present invention to provide a seal packing which has high resiliency and restoration from deformation, and which is unlikely to be peeled off during handling.

It is a third object of the present invention to provide a seal packing which is low in manufacturing cost.

In order to achieve these objects, the present invention provides a seal packing for an automobile air conditioner characterised in that a tubular body is formed by subjecting a foam rubber material to extrusion moulding, the foam rubber material is vulcanised during the extrusion moulding and thereby smooth skin layers are moulded,, integral with the foam rubber material, on both inner and outer peripheral surfaces of the tubular body.

According to the present inventiont there is provided a tubular.seal of a foam material, the inner and outer peripheral surfaces thereof comprising respective integral smooth skin layers.

The expresi,,ion "tubular" in the specification and claims does not imply that the cross-section is necessarily circular.

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Such a seal according to the present invention may be configured in a way that a tubular body is formed by subjecting a foam rubber material to extrusion - moulding,, the foam rubber material is vulcanised during the extrusion moulding and thereby smooth skin layers are moulded, integral with the foam rubber material, on both inner and outer peripheral surfaces of the tubular body. Therefore, the seal packing has smooth surface with fine holes which have little or no influence on the sealability of the seal packing, and which thus enhance the air tightness and water resistance of the packing itself.

Further, since this seal packing may be formed of a foam rubber material having in its centre a longitudinally-extending hollow portion, the seal packing has higher resiliency as compared with a conventional seal packing and provides quicker restoration from deformation. Even when a unit provided with this- seal packing is inserted between _units (or in other narrow spaces), the seal packing is not readily peeled off. so enhancing handling workability.

Moreover. in the manufacture of this seal packing. it can be moulded without requiring the aforementioned steps of peeling off a backing paper after the skin layer has beep formed.on the body. Therefore, the manufacturing^steps may be simplified so reducing the the manufacturing cost.

The invention may be carried into practice in -various ways on one specific embodiment will now be described,,-by way of example, with refexence to the accompanying drawings, in which:

Figures 1 (a), (B) and (C) are perspective views 6 of a seal packing according to an embodiment of the present invention; Figure 2 is a schematic view showing the manufacturing steps for a seal packing according to the same embodiment; Figure 3 is a front view showing a mounting step for a cooler unit on which the seal packing of Figure 1 is mounted; Figures 4 and 5 are section views of a known seal packing; and Figure 6 is a front view showing a mounting step for a cooler unit on which a conventional seal packing is mounted.

As shown in Figure l(C), a seal packing 10 according to the present embodiment has a tubular body 12 having a longitudinally-extending circular-section hollow portion 11 in the centre thereof. A flat portion 16 is formed in part of another peripheral surface 15 of the body 12. This flat portion 16 serves as a portion to which one surface of a doublesided adhesive tape 13 is struck. The other surface of the tape 13 is stuck to a mating surface of a flange portion F formed on a cooler unit 2 shown in Figure 3. for example.

The tubular body 12 is formed from foamed rubber materiall which is interiorly formed with cells such as fine holes caused by foaming. However# the inner peripheral surface-14 and outer peripheral surface 15 of the body 12 are covered by a smooth skin layer 17 with fine holes which have no influence on the sealability of the seal packing. Typical materials used in the present embodiment include ethylenepropylene diene methylene rubber (EPDM)r Styrene rubber 10.

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17 P I t I 7 (SBR), butadienerubber (BR), nitrile rubber (NBR) and the like.

This seal packing 10 is produced using the following procedure.

The first step of the manufacturing method comprises introducing the raw material of rubber along with a foaming agent, a vulcanising agent and other additives into an extrusion moulding apparatus 20 as shown in. Figure 2.

The second step comprises suitably mixing these materials within the extrusion moulding apparatus 20 to extrude the mixture from a mould 22 by means of a screw 21.

The third step comprises moulding the material W extruded from the mould 22 into a tubular configuration using the mould 22 and transferring it into a heating -furnace 24 by means of a conveyer 23. At that time,,the surfaces of the material in contact with the su rface of the mould 22. (that is,' the inner peripheral surface 14 and the outer peripheral surface 15) are forme with skin layers 17 integral with the hollow tubular body W. Figure l(A) shows the material W before its transfer to the heating furnace-24.

The fourth step comprises heating the material within-the heating furnace 2.4. The temperatures and other conditions within the furnace need to be adjusted to their required values according to the properties of the product to be obtained. since the heating conditions will influence the increase in produce size on foaming, along with other properties such as resilience.

For example, in case of the present embodiment, the conditions are: temperature - 1500C. vapour 5.

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pressure - about 5 kg/cm2j and heating time - about 5 minutes.

in the furnacer the foaming agent, is cracked to produce fine cells in the material. This state is shown in Figure 1 (B). During the foaming reaction only the foaming agent is independently reacted not the rubber materialg and therefore, the cells are individually scattered leaving spacings in the material. This is a totally different foaming mechanism from the case of the aforementioned open-cell foam urethane material. More specifically,, in the case of the present embodiment, when the foaming agent is reacted to expand, the rubber material around the foaming agent is ' pressed whereby the whole material W expands, giving no influence on the skin layer 17 formed at the time of extrusion moulding.

In the fifth step,-the material W foamed within the heating furnace 24 is transported by the conveyor 23 and a lubricant such as silicone is coated by an applicator 25 on the outer peripheral surface 15 of the material W.

In the sixth step, a double-sided adhesive tape 13 is stuck by a tape applicator 26 onto the flat portion 16 of the material W.

Finally, the material W is cut by a cutter 27 into the required lengths and is stored as a seal packing 10 in a storage case 28.

The moulded seal packing 10 is stuck to A flange portion-F of a cooler unit 2 moulted below an instrument panel 6 of a vehicle body, as shown in Figure 3. In this casej, the seal packing 10 is hardly peeled off or moved from its position when the cooler unit 2 is inserted between the intake unit 1 and the k 7 9 1 ill 10.

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heater unit 3. This is because the resiliency of the seal packing 10 is high and restoration from deformation is quickly achieved so that the contact surface between the packing 10 and flange portion F is not subjected to a large shearing force. - Thishigh resiliency of the seal packing 10 results from the fact that.the material of the packing 'is a foam rubber which has the hollow portion 11 in the longitudinal direction thereof. Further. the rapid restoration from deformation results from the fact that the hollow portion 11 is formed in the longitudi nal direction of the seal packing 10 and the skin layer 17 is formed on the inner peripheral surface 14 thereof.

-In a solid_foam rubber material not formed with the hollow portion 11, deformation such as a collapse tends to be absorbed by deformation of the fine holes within the foam rubber. Thusi restoration of the original shape takes some time. On the other hand, in the seal packing 10 of the present embodiment, deformation such as a collapse is mainly absorbed by deformation of the circular-section hollow portion 11. Thust the original shape is restored considerably more quickly than is the case with the prior art.

In additiony in this seal packing 10i when the foaming agent is mixed into the rubber material and the foaming agent is cracked to foam and mould the rubber material. the interior thereof is foamed after-the surface has been vulcanised. Therefore. the skin layer 17 has a smooth surface with fine holes which have practically no influence on sealability of the seal packing. Accordingly. the overall seal packing 10 has good air tightness and water resistance.

Moreover, when the seal packing is produced as described there is no need for the step of peeling off a backing paper after the skin layer has been formed on the body. neither is there a need for the bending of the body as is required in the prior art. Therefore. the manufacturing process can be simplified and the manufacturing cost can be reduced.

It is to be noted that the present invention is not limited to the aforementioned embodiment but various modifications can be made. For examplei the sectional shape of the hollow portion formed in the longitudinal direction of the seal packing is not limited to a circular shape and could be a triangle or other polygon.

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Claims

CLAIMS,

1. A tubular seal of a foam material, the inner and outer peripheral surfaces thereof comprising respective integral smooth skin layers.

2. A seal as claimed in Claim 1 in which the material-is foam rubberj, andthe skin layers comprise vulcanised rubber.

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3. A seal as claimed in Claim 1 or Claim 2 in which the inner peripheral surface is generally cylindrical.

1 4. A seal as claimed in any one of the preceding Claims in which the outer peripheral surface is 15. generally part-cylindrical.

-5. A seal as claimed in any one of the preceding claims in which the outer peripheral surface includes a longitudin ally-extending flat portion for attachment to 20. a support.

6. -A seal as claimed in Claim 5 in which the flat portion carries doublesided adhesive tape.

7. A seal as claimed in any one of the preceding claims which is extrusion moulded.

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- 8. A seal substantially as specifically described,, with reference to Figure l(C).

9. A method of manufacturing a tubular seal 12 comprising forming inner and outer peripheral smooth skin layers on a tubular blanky and foaming the. material of the blank intermediate the skin layers.

10. A method as claimed in Claim 9 in which the foaming takes place subsequent to the formation of the skin layers.

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11. A method as claimed in Claim 9 or 10 in which the material is substantially rubber. and the skin layers are formed by vulcanisation.

12. A method as claimed in any one of Claims 9 to 11 in which the blank is produced by extrusion moulding.

13. A method as claimed in any one of Claims 9 to 12 in which the material is foamed by being heated.

14. A method as claimed in Claim 11 in which the 20. blank is produced by continuous extrusion moulding, and is passed into a heater, thereby foaming the rubber.

15. A method of manufacturing a tubular seal substantially as specifically described with reference to Figure 2.

Published 1988 at The Patent Offtce, State House, 66171 High Holborn, London WUR 4TP. Further copies may be obtained from The Patent OffLee, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1/87.

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