Winding – tensioning – or guiding – Reeling device – Multiple windings
Reexamination Certificate
1998-08-19
2001-03-06
Walsh, Donald P. (Department: 3653)
Winding, tensioning, or guiding
Reeling device
Multiple windings
C439S015000, C439S164000, C181S286000, C181S290000, C181S294000
Reexamination Certificate
active
06196488
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a sound-absorbing material and a cable reel including the same, and more particularly to a sound-absorbing material preferably adapted to be used in a cable reel which is mounted on a steering device for an automotive vehicle and electrically interconnects a stationary member assembly and a movable member assembly through a flat cable.
In an automotive vehicle equipped with an air bag, a cable reel is provided in a steering wheel in order to supply electrical power to an air bag system. For convenience of explanation, such a cable reel will be described below by referring to the drawings.
FIGS. 5A
to
5
C show an example of a conventional cable reel.
FIG. 5A
is a schematic longitudinal sectional view of a conventional cable reel.
FIG. 5B
is a perspective view of a conventional sound-absorbing material.
FIG. 5C
is a fragmentary cross sectional view of the sound-absorbing material shown in FIG.
5
B.
As shown in
FIG. 5A
, the conventional cable reel includes a movable member assembly
10
which rotates together with a steering wheel, and a stationary member assembly
11
which is secured to a stationary shaft on a body frame. The movable and stationary member assemblies
10
and
11
define an annular cable containing chamber
12
which accommodates a flat cable
15
in a coiled state. Opposite ends of the flat cable
15
in the coiled state are connected to lead wires which are led out from the movable and stationary member assemblies
10
and
11
, respectively, to be connected to an external connector or electrical wires. In such a cable reel, the flat cable
15
is wound in the cable containing chamber
12
when the steering wheel is turned in either a clockwise or counter clockwise direction while the flat cable
15
is unwound in the chamber
12
when the steering wheel is turned in the other direction, so that a device (air bag) on the steering wheel is electrically connected to a power source on the body frame.
The cable reel involves a problem in that an unpleasant sliding noise is generated when the lateral opposite edges of the flat cable
15
slide on upper and lower bearing surfaces of the cable containing chamber
12
upon winding and unwinding of the flat cable
15
in the chamber
12
. The flat cable
15
vibrates in an axial direction (from an upper to lower direction or from a lower to upper direction) of the steering wheel during idling or driving of the automotive vehicle, thereby giving rise to an unpleasant vibration noise due to collision between the bearing surfaces of the chamber
12
and the lateral opposite edges of the flat cable
15
.
Japanese Utility Model Publication No. HEI 6-36040 (1994) discloses a cable reel in which a highly lubricative sheet such as a polytetrafluoroethylene (PTFE) resin or the like is stuck on at least one of bearing surfaces of a cable containing chamber in order to attenuate sliding noise. Also, Japanese Patent Public Disclosure No. HEI 8-104471 (1996) discloses a cable reel in which a sound-absorbing material made of a resilient material such as a rubber or the like or a sound-absorbing material with the polytetrafluoroethylene (PTFE) resin is attached to bearing surfaces of stationary and movable member assemblies by means of clamps provided on the surfaces.
A polytetrafluoroethylene resin sheet is stuck by way of PET (polyethylene telephthalate) on a surface of a rubber sheet since the former lacks adhesion to the latter.
Although the polytetrafluoroethylene resin sheet disclosed in Japanese Utility Model Publication No. HEI 6-36040 (1994) can attenuate the sliding noise on account of its high lubrication, it cannot reduce noise which is caused by collision of the flat cable with the bearing surfaces of the cable reel due to axial vibrations of the cable in a coiled state. In particular, such collision noise is likely to be accentuated when an engine is idling. On the other hand, the resilient sheet disclosed in Japanese Patent Public Disclosure No. HEI 8-104471 (1996) hardly attenuate sliding noise, since the lubrication between the flat cable and the resilient sheet is poor, although the sheet can reduce the collision or vibration noise.
In a sound-absorbing material
50
shown in
FIG. 5C
, a rubber sheet
50
a
having a polytetrafluoroethylene (PTFE) resin sheet
50
c
provided thereon can attenuate and absorb sliding noise and vibration noise by means of a highly lubricative resin and rubber sheet.
As shown in
FIG. 5C
, however, the rubber sheet
50
a
cannot absorb vibration noise effectively, since the rubber sheet
50
a
is a flat single layer, and therefore the sound-absorbing material cannot obtain an effective sound-absorbing function.
Also, as shown in
FIGS. 5A and 5B
, a rubber sheet
50
a
, a polyethylene telephthalate (PET) film
50
b
and a polytetrafluoroethylene (PTFE) resin sheet
50
c
must be punched out into an annular shape adapted to be used, since the bearing surfaces of the cable containing chamber
12
is in an annular form. Consequently, this involves much loss of material. In particular, a total cost of the cable reel becomes high since the PTFE resin sheet is expensive.
In addition, the above sound-absorbing material involves high costs due to an increase in working steps, since the PET film
50
b
is stuck to the rubber sheet
50
a
using an adhesive and then the PTFE resin sheet
50
c
is attached to the PET film
50
b
using an adhesive.
Moreover, the above sound-absorbing material gives rise to a problem in that it reduces a sound-absorbing effect since the hard PET film
50
b
is interposed between the rubber sheet
50
a
having a sound-absorbing function and the PTFE resin sheet
50
c
having a lubricative function. It is difficult to produce the PTFE resin sheet
50
c
having a low thickness since it is produced by means of skiving. Consequently, the sheet
50
c
on the market is usually more than 20 &mgr;m. Such a thick PTFE resin sheet
50
c
in addition to the hard PET film
50
b
will lower the sound-absorbing function.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a sound-absorbing material and a cable reel including the same which can effectively attenuate both sliding noise and vibration noise and can be produced inexpensively.
In order to achieve the above object, a sound-absorbing material in accordance with the present invention is characterized in that: the sound-absorbing material is made of a resin film; the resin film is formed into a thin waved sheet having continuous wave crests and troughs by bending the resin film at a fine pitch; and a distance between a top of each wave crest and a bottom of each wave trough is set to be small so as to make a virtual thickness of the sheet thin.
In the above sound-absorbing material, an air layer is defined in a space surrounded by the wave crests and the wave troughs. Sliding noise and vibration noise can be efficiently attenuated when the sound waves generated by the noise collide with crests or troughs in the said material.
The resin film may be a polyethylene film or a polytetrafluoroethylene resin film. The film has a lubricative surface. As a high lubricative function can be obtained by the polytetrafluoroethylene resin film, the sliding noise can be more effectively attenuated.
A thin synthetic paper having a lubricative surface may be attached on the wave crests to be set as a bearing side.
The synthetic paper is produced from a main material made of a synthetic resin (e.g., a main material of a polyethylene resin and a mixture of an inorganic filling material and a little additive) while forming a number of microvoids (fine cavities) and laminating a smooth surface layer on a formed base layer by means of the biaxial extension film forming method (Tradename: YUPO).
The synthetic paper has the same superior lubricity as a conventional polytetrafluoroethylene resin sheet and is cheaper than the polytetrafluoroethylene resin sheet. This results in cost-down.
In the prior art, in order to make a surface of the rubber material lubrica
Iizuka Tetsuya
Maegawa Akihito
Sakata Tomoyuki
Bierman, Muserlian and Lucas
Rivera William A.
Sumitomo Wiring Systems Ltd.
Walsh Donald P.
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