Seals for vehicles

Details Seals for vehicles Seals for vehicles

2000-01-28

2002-12-03

Thomas, Alexander S. (Department: 1772)

Movable or removable closures

Closure seal; e.g., striker gasket or weatherstrip

U-shaped member or portion mounts seal

C049S475100, C049S498100, C428S122000, C428S099000, C428S492000

Reexamination Certificate

active

06487820

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to seals used in vehicles, such as weather strips, and, more particularly, to procedures and facilities for manufacturing these seals.
2. Description of Related Art
Weather strips are used for sealing automobile passenger compartments to prevent rain, washing water, mud, noise and the like from entering the passenger compartment. Opening trim (OT) weather strips (hereafter referred to as “OT weather strips”) and door weather strips seal a space defined between the doors and the body panels located adjacent to the doors. Door glass run channels seal a space between the door frames and the door glasses moving along the door frames.
A typical OT weather strip includes a U-shaped trim and a tubular seal formed integrally with the trim. The trim is secured to a peripheral flange of a door opening of a body panel. Since the trim is required to have a predetermined degree of strength, the trim is formed by embedding a metal core with ethylene-propylene-diene copolymer (EPDM), solid rubber. The outer side of the trim is covered by a decorating layer formed of, for example, thermoplastic elastomer (TPE). It is also required that the seal has an elastic property at the low-temperature. The sealing is thus formed of EPDM sponge rubber.
FIG. 11
shows a conventional-type procedure for manufacturing the OT weather strip. Specifically, a supplier
106
supplies a plate-like metal core to an EPDM solid rubber extruder
101
. The metal core is then embedded by unvulcanized solid rubber and supplied to a first die
102
. Meanwhile, an EPDM sponge rubber extruder
100
supplies unvulcanized EPDM sponge rubber to the first die
102
. The sponge rubber, together with the solid rubber embedding the metal core, is extruded through the first die
102
and formed as one body, or a workpiece having a predetermined shape. The workpiece including unvulcanized rubber is sent to a microwave heating vulcanizing device (UHF device)
103
in which the workpiece is pre-heated. While the workpiece is passing through the UHF device
103
, a foaming agent contained in the EPDM sponge rubber activates and starts foaming the rubber. The workpiece is then sent to an air heating vulcanizing furnace
104
. By passing the workpiece through the air heating vulcanizing furnace
104
, the EPDM rubber is completely vulcanized. The workpiece including the vulcanized rubber is then cooled in the air.
Meanwhile, olefine type thermoplastic elastomer (TPO) used for forming the decorating layer of the trim is molten in a TPO extruder
105
. The molten TPO is shaped like a sheet by second die
107
through extrusion molding. Then, the sheet-like TPO is press-fit on the workpiece by a roller. In this manner, the outer side of the trim is covered by a TPO decorating layer. Subsequently, the workpiece is again cooled in the air and bent such that the trim has a U-shaped cross section. The bent workpiece is then cut in a plurality of pieces by a cutter
108
. The cut pieces are arranged in a cavity defined in a metal mold such that the pieces are separate from one another while inclined relative to one another by predetermined angles. EPDM sponge rubber is then injected in the cavity and connects the cut pieces with one another. A complete OT weather strip is thus obtained.
In the above conventional-type procedure, the rubber material and TPO may be shaped as one body through co-extrusion molding, instead of shaping TPO separately. In this case, the second die
107
is unnecessary. However, since the vulcanizing temperature of the rubber is normally 180° C. to 220° C. TPO is re-molten in a vulcanizing device in which the rubber is vulcanized. The re-molten TPO affects the appearance of the weather strip. Accordingly, as described above, TPO and the rubber must be treated separately before the shaped TPO is press-fit on the vulcanized rubber material.
Furthermore, in the above procedure, the trim formed of vulcanized rubber may be placed in the second die
107
. The molten TPO is then arranged on the trim in the second die
107
such that the trim is covered by the decorating layer. However, in this case, it is very difficult to supply the trim to the second die
107
at a predetermined position. As a result, the obtained TPO decorating layer does not have a uniform thickness. In addition, if the molten TPO needs to be provided only to a certain portion of the trim, the structure of the second die
107
becomes extremely complicated. The manufacturing costs of the OT weather strip is thus increased. Therefore, in order to reduce the manufacture costs, a second die
107
with a simple structure is used in the conventional-type procedure. However, if TPO is shaped like a sheet by the second die
107
, the sheet-like TPO must be independently press-fit on the workpiece after the rubber vulcanization is completed. This press-fitting step complicates the procedure for manufacturing the OT weather strip. Accordingly, it is necessary to provide a procedure for manufacturing a weather strip capable of reducing costs and of simple performance.
A typical door glass run channel has a bottom wall, a pair of side walls, a pair of support lips, and a pair of lip seals. The support lips and the lip seals extend from the distal ends of the associated side walls. The support lips clamp an edge of a door frame that defines an opening in the door frame for receiving a door glass. Each lip seal comes in contact with an inner side of the door glass facing the passenger compartment or an outer side of the door glass facing the exterior of the vehicle. The lip seals are opposed to each other such that the lip seals guide the door glass to move smoothly along the door frame. When a door glass is closed, the lip seals come in contact with the inner and outer sides of the door glass for sealing the passenger compartment, or preventing rain, washing water, mud, noise and the like from entering the passenger compartment. Most of the door glass run channel is formed of a single type of material, such as EPDM solid rubber and TPO. A polyurethane layer is applied on the surfaces of the lip seals and other portions of the door glass run channel coming in contact with the door glass. The polyurethane resin layer allows the door glass to slide smoothly along the door glass run channel.
FIG. 12
shows a conventional-type procedure for manufacturing the door glass run channel. An EPDM extruder
101
supplies unvulcanized EPDM solid rubber to a die
110
. The EPDM solid rubber is then shaped in a predetermined shape by the die
110
through extrusion molding. The shaped rubber is sent to a UHF vulcanizing device
103
and then to an air heating vulcanizing furnace
104
in which the rubber is vulcanized. The rubber is then cooled in the air such that a workpiece of the door glass run channel is obtained.
Next, the workpiece is sent to a polyurethane coating booth
111
in which a solution of polyurethane is applied and coated on the workpiece. The workpiece is then passed through a drying furnace
112
in which solvent contained in the solution is evaporated. Subsequently, the workpiece is sent to a solidifying furnace
113
and solidified in the furnace
113
. The workpiece is then cooled and cut in a plurality of pieces by a cutter
108
. The cut pieces are arranged in cavity defined in a metal mold such that the pieces are separate from one another and inclined relative to one another by predetermined angles. The pieces are then connected with one another by EPDM solid rubber or TPO injected in the cavity. A complete door glass run channel is thus obtained.
The above procedure includes an independent step of applying a polyurethane coating on the lip seals and another independent step of solidifying the polyurethane. These steps prolong the time required for performing the procedure for manufacturing the door glass run channel. Furthermore, the steps for forming the polyurethane layer complicate the procedure and thus increase the cost for manufacturing the door glass run channel.
Fu

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