Metal V-belt

Details Metal V-belt Metal V-belt

1999-10-26

2002-01-01

Hannon, Thomas R. (Department: 3682)

Endless belt power transmission systems or components

Friction drive belt

Including plural interconnected members each having a drive...

C474S240000, C474S201000

Reexamination Certificate

active

06334830

ABSTRACT:

RELATED APPLICATIONS
The application claims the priority of Japanese Patent Application No.10-367661 filed on Dec. 24, 1998, which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention is related to a metal V-belt used as a power transmission means in a V-belt infinite variable-speed drive and in particular to a metal V-belt that comprises metal elements.
BACKGROUND OF THE INVENTION
This type of metal V-belt has been proposed many times from the past and as shown in
FIG. 8
is comprised by, for example, an endless belt shaped metal ring
14
and a plurality of metal element members
80
supported along the metal ring member. Further, this metal V-belt transmits power between a drive pulley
11
and a driven pulley
12
. Both of these pulleys
11
,
12
can variably control the V-channel width and by means of variably controlling the V-channel width of both pulleys, the wrapping radius of the metal V-belt on both pulleys can be changed and the change gear ratio between the drive axle and driven axle changed in infinite steps.
As shown in
FIG. 9
for example, the metal element members
80
are comprised by a neck portion
7
that joins the gap between a body portion
3
and a head portion
4
. Slot portions are formed on both sides of the neck portion
7
which accept the metal ring members
14
. A saddle surface
1
is formed on the upper portion of the body portion
3
making contact with the metal ring members
14
at the winding regions of the drive pulley and the driven pulley. A V-surface
2
is also formed on both sides of the body portion
3
making contact with the V-channel. In contrast, an ear portion
86
is drawn to the left and right on the left and right sides of the head portion
4
(upper portion of slot). This ear portion
86
prevents the metal element members from detaching from the metal ring member.
Further, an endless ring shaped metal V-belt is formed by means of accepting the metal ring members
14
in a slot formed by the saddle surface and the ear portion and, as shown in
FIG. 8
, joining the plurality of metal elements. When lining up the metal element members
80
at the approximate center of the head portion
4
as a plurality of a push type members, an approximate cylindrical shaped convex portion
5
and concave portion (not shown in figure) which are called couplings are formed on the front and rear surfaces of the belt in the travel direction in order to join and position the front and rear metal element members. Then, a composition is made in which the linear portion between the two pulleys is positioned continuously by means of joining the convex portion and concave portion of the front and rear surfaces of the metal element members to each other.
An slanted surface
20
(or recessed surface) is formed on the front surface of the metal element member at the pulley winding region such that is does not interfere with the body portion and a rocking edge
21
that is formed by this slanted surface and the front surface at the pulley winding region functions as a pitch circle pressing on the front and rear metal element members. Further, in the following description the metal element members will be referred to as members and the metal ring member as a ring.
In this type of metal V-belt the driving force transmits to the driven pulley
12
by means of the elements which are protruding from the drive pulley
11
outlet being positioned by joining the convex portion and concave portion of the front and rear elements which then functions as push type members. Therefore, a compressive force acts on each element at the arcing portion of the belt directed from the drive pulley to the driven pulley without any clearance occurring between the front and rear elements. In contrast, an expansive force is applied to the ring member at the arcing portion of the belt directed from the driven pulley to the drive pulley although no mutual tensile force occurs because each of the elements are gathered together in a plate shaped body. In addition, because almost all the clearance between every element is gathered at this portion, a fixed amount of clearance occurs between the elements at this return region.
Unevenness occurs in the gaps between each element close to the driven pulley outlet when this clearance is left as is without changes and as a result, the elements protruding from the driven pulley outlet enter the drive pulley inlet while there is still clearance. Consequently, a large amount of slippage occurs in the drive pulley from the difference in the speeds of the drive pulley inlet and outlet causing problems such as friction of the pulleys and elements and decreases in the power transmission efficiency.
Thereupon, this type of metal belt requires each element to be comprised to promote clearance closure movement. This clearance closure movement is a movement that functions to join the elements (protruding from the driven pulley) with the elements closest to the drive pulley just before the elements (protruding from the driven pulley) are inserted into the drive pulley in the early stage in the driven pulley outlet arcing region.
A method has been disclosed for this clearance reducing motion in, for example, Japanese Laid-open Patent Publication No.02-225840(A) in which the composition is such that the center of gravity of transverse elements (elements) are positioned at the outside in the radial direction close to the slanting region of the transverse elements or against the elements thereby maintaining the impact force when the transverse elements protrude from the driven pulley. As a result of this impact force, the transverse elements are mutually joined at the return portion without any play and then mutually fit into the drive pulley without any play.
Further, this type of metal V-belt is already being used for practical applications although in its present state there are requests for improvements in the power transmission efficiency and improvements in the durability. To respond to these types of improvements several methods have been disclosed in, for example, Japanese Utility Model Publication No.05-008359(B), Japanese Laid-Open Utility Model Publication No.62-037645(A) and Japanese Laid-open Patent Publication No.06-010993(A).
From among these applications the method disclosed in Japanese Utility Model Publication No.05-008359(B) is one wherein the elements separated from the pulley at the driven pulley outlet arcing portion pitch at the clearance region as described above and the lower portions of the ear portions of the elements (lower portion of
86
in
FIG. 9
) strike the outermost periphery (highest portion of
14
in
FIG. 9
) by point contact. In order to prevent this point striking action from occurring, the two contact surfaces between the element shoulder (saddle surface
1
in
FIG. 9
) and the ear of the element are formed in a concentric circular arc shape thereby bringing the ear portion and the ring into surface contact even when the elements pitch to improve the durability.
Moreover, a method which is known is disclosed in Japanese Laid-open Patent Publication No.06-010993(A) and has an objective of improving the power transmission efficiency. In this method a rotational moment acts on the elements due to a frictional force acting between the pulley and the elements and a frictional force acting between the elements and the rings at the winding portion of the pulleys. Because the center of the moment at this time is almost located in the slanting region at the center between the principal planes, the result of the moment is such that the elements slip between the pulleys leaning slightly rearward towards the travel direction of the belt. In order to prevent this slippage, there is a means that provides a shape in the direction of the plate thickness of a support surface such that the point where the force acts in the radial direction due to tension in the ring acts on the outside away from the center of the direction of the plate thickness of the support surface that makes contact with the ring

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