Sliding key and continuously variable transmission

Details Sliding key and continuously variable transmission Sliding key and continuously variable transmission

2000-06-05

2001-11-20

Estremsky, Sherry (Department: 3681)

Endless belt power transmission systems or components

Pulley with belt-receiving groove formed by drive faces on...

By manual actuator for one or both confronting members

C029S892000, C474S035000

Reexamination Certificate

active

06319162

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a sliding key that consists of a composite molded product made of a metal-molded part and a resinous part and can be suitably used in a severe environmental condition of a high temperature and no lubrication and a continuously variable transmission using the sliding key.
BACKGROUND ART
As a construction of a continuously variable transmission using a sliding key, the pulley construction is known in which a stationary key rotating with a rotary shaft and a movable pulley having a sliding cylinder are engaged each other through the sliding key (Japanese Patent Application Laid-Open No. 8-219258).
With reference to
FIGS. 4 and 5
, the conventional pulley construction of the continuously variable transmission is described below.
FIG. 4
is a half-sectional view showing the pulley construction in the axial direction of the rotary shaft.
FIG. 5
is a perspective view showing a main portion of the rotary shaft.
A rotary shaft
4
that is driven by an engine not shown is supported on a body
6
of the continuously variable transmission by bearings
5
a
,
5
b
. A stationary pulley
7
is formed integrally with the rotary shaft
4
such that the stationary pulley
7
projects outward from the rotary shaft
4
. Grooves
4
b
are formed concavely into the periphery of a stepped portion
4
a
formed on the periphery of the rotary shaft
4
such that the grooves
4
b
are long in the longitudinal direction of the stepped portion
4
a
and spaced at regular intervals in the circumferential direction thereof. A sliding key
1
is fitted into the groove
4
b
and engages a movable pulley
8
having a slidable cylindrical portion
8
a
, such that the movable pulley
8
operates in contact with the stationary pulley
7
or separably therefrom. The sliding key
1
that is fitted into the groove
4
b
is required mainly to have a rotation-stopping function or a power-transmitting function. The sliding key
1
is also required as an additional function to have a reciprocating function in the axial direction of the rotary shaft
4
. Referring to
FIG. 4
, reference numeral
9
denotes a V-belt spanned between the stationary pulley
7
and the movable pulley
8
.
The sliding key
1
is hitherto formed of metal or a material having a low friction coefficient. As the material having a low friction coefficient, a mixture of polyimide resin, polytetrafluoroethylene resin, and graphite or a mixture of polyetherether ketone resin, carbon fiber, and polytetrafluoroethylene resin is used.
However, in the case where the groove into which the sliding key is fitted is made of metal, sliding contact occurs between the metal of the sliding key and that of the groove. Thus, when the sliding key is used in an environment of a high temperature and a high load, the friction resistance of the sliding key becomes large owing to friction-caused seizing of the metals or corrosion. As a result, the sliding key malfunctions or fails. Using a ball spline construction instead of metal leads to a complicated construction and a high cost.
A conventional sliding key made of a resinous material having a low friction coefficient melts, deforms or has a high friction resistance, when it is used in an environment of a high temperature and a high load. Consequently, it is destroyed in a short period of time.
The present invention has been made to overcome the problem. Thus, it is an object of the present invention to provide a sliding key that does not malfunction or fail when it is used in an environment of a high temperature and a high load and also provide a continuously variable transmission using the sliding key.
DISCLOSURE OF THE INVENTION
The sliding key of the present invention that engages a sliding cylinder with sliding in an axial direction and follows a rotation of a rotary shaft comprises a composite molded product made of a metal-molded part and a resinous part.
The resinous part forming an integral molded product consists of an injection-moldable resinous composition.
The continuously variable transmission of the present invention includes a stationary pulley rotating with a rotary shaft having a plurality of grooves formed on a peripheral surface thereof at appropriate intervals in a circumferential direction thereof and having a sliding key fitted into each of the grooves; and a movable pulley having a sliding cylinder having a plurality of grooves each of which has a width to receive the sliding key and extends axially on an inner peripheral surface thereof such that the grooves are located at appropriate intervals in correspondence to the grooves formed on the peripheral surface of the rotary shaft. The sliding key is the sliding key of the present invention.
The sliding key of the present invention is a composite integral molded product of the metal-molded part and the resinous part. Thus, when the sliding key is used in an environment of a high temperature and a high load, it does not malfunction or fail. Further, because the resinous part is made of the injection-moldable resinous composition, it is easy to form the sliding key having a complicated configuration or construction. Therefore, the sliding key of the present invention is smaller, lighter, and lower in cost than a ball spline conventionally used.
Because the continuously variable transmission of the present invention uses the sliding key, it is allowed to have a simple construction and a smooth operational performance in an unlubricated atmosphere.


REFERENCES:
patent: 4075902 (1978-02-01), Charchian et al.
Patent Abstract of Japan, 08219258, Aug. 27, 1996.
Patent Abstract of Japan, 1-169650, U1, Nov. 30, 1989.
Patent Abstract of Japan, 10026198, Jan. 27, 1998.

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