Machine element or mechanism – Mechanical movements – Rotary to intermittent unidirectional motion
Reexamination Certificate
1999-10-21
2001-04-24
Fenstermacher, David (Department: 3682)
Machine element or mechanism
Mechanical movements
Rotary to intermittent unidirectional motion
C074S116000
Reexamination Certificate
active
06220107
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an eccentric orbiting type speed changing device for performing deceleration or acceleration by eccentrically rotating pinions or transmission disks.
As a conventional eccentric orbiting type planetary reduction gear device, for example, known is such a device comprising a casing having an internal gear at an inside periphery, two sheets of pinions held in the casing separately in an axial direction and defined on an outside periphery with external gears to be in mesh with the internal gear, a carrier having a pillar-like portion passing through the pinions in the axial direction, and an eccentric crank shaft causing these two sheets of pinions to eccentrically rotate under a condition of deviating phases thereof by 180 degree.
However, the conventional eccentric orbiting type planetary reduction gear device has a big problem generating large vibrations and noises.
An inventor of this patent application made earnest studies on mechanisms generating vibrations and noises in the eccentric orbiting type planetary reduction gear device, and came to the following findings. Namely, when the eccentric orbiting type planetary reduction gear device
11
reduces the speed as shown in
FIGS. 7
,
8
and
9
, the gearing engagement in an X direction (tangential direction) as well as the gearing engagement in a Y direction (radius direction) act on respectively from the external gears of the pinions to the internal gear of the casing
12
by the rotation of the pinions
13
,
14
. Further, the pinions
13
,
14
are respectively acted by the centrifugal force in the Y direction by the revolution thereof. At this time, the engaging forces Fx and Fy in the X and Y directions in the pinion
13
as well as the engaging forces −Fx and −Fy in the X and Y directions in the pinion
14
are equal in values, but the working directions are reverse, and the centrifugal forces P and-P in theY direction in the pinions
13
,
14
are equal values but the working directions are reverse. Consequently, the resultant force of the engaging forces in the X and Y directions and the resultant forth of the centrifugal force are made zero and balanced with respect to the force. Herein, it is presumed that the engaging force is a single force acting on center flat faces a, b in the gear width of the pinions
13
,
14
in a maximum engaging parts of the pinions
13
,
14
and the casing
12
, and on the other hand it is presumed that the centrifugal force is a single force acting on the center of gravity of the pinions
13
,
14
. However, when observing the engaging forces Fy and −Fy in the Y axial direction and the centrifugal forces P and −P in the pinions
13
,
14
on the flat faces including Y and Z axes together as shown in
FIG. 10
, both engaging forces Fy, −Fy and the centrifugal forces P, −P are separatedby a distance L, and consequently couple of forces of Mf=Fy×L (moment of rotation) and couple of forces of Mp=P×L (moment of rotation) are created by both engaging forces Fy, −Fy and the centrifugal forces P, −P,, and accordingly the resultant force of the engaging force and the resultant forth of the centrifugal force are imbalanced with respect to the moment of rotation in the prior art. Since such moment of rotations (couple of forces) are imparted to a crank pin
15
and are gradually deviated toward a circumferential direction following eccentric rotations of the pinions
13
,
14
, the eccentric orbiting type planetary reduction gear device
11
is periodically vibrated to cause large vibrations and noises.
SUMMARY OF THE INVENTION
The invention has been realized based on such findings, and is to provide an eccentric orbiting type speed changing device capable of effectively suppressing vibrations and noises at deceleration and acceleration.
Such an object can be accomplished by
firstly, the eccentric orbiting type speed changing gear device, comprising a casing having an internal gear at an inside periphery, three sheets of pinions held in the casing separately in an axial direction and defined on an outside periphery with external gears to be in mesh with the internal gear, a carrier having a pillar-like portion passing through the pinions in the axial direction, and an eccentric rotating means which causes one sheet of center pinion and two sheets of pinions positioned at both sides of said center pinion to perform eccentric rotations under a condition of deviating phases of said center pinion and both side pinions by 180 degree, and in which distances between a center line in the gear width of the center pinion and both center lines in the gear width of two sheets of both side pinions are substantially equal;
secondly, the eccentric orbiting type speed changing gear device, comprising a casing having an internal gear at an inside periphery, four sheets of pinions held in the casing and defined on an outside periphery with external gears to be in mesh with the internal gear, a carrier having a pillar-like portion passing through the pinions in the axial direction, and an eccentric rotating means which causes two sheets of center pinions of the same phases and two sheets of pinions of the same phases positioned at both sides of said center pinions to perform eccentric rotations under a condition of deviating phases of said center pinions and both side pinions by 180 degree, and in which distances between both center lines in the gear width of two sheets of center pinions and both center lines in the gear width of two sheets of both side pinions are substantially equal;
thirdly, the eccentric orbiting type speed changing device, comprising a cylindrical casing, three sheets of transmission disks held in the casing separately in an axial direction and outside peripheries thereof rolling-contacting an inside periphery of the casing and diameters thereof being smaller than an inner diameter of the casing, a carrier having a pillar-like portion passing through the transmission disks in the axial direction, and an eccentric rotating means which causes one sheet of center transmission disk and two sheets of transmission disks positioned at both sides of said center transmission disk and to perform eccentric rotations under a condition of deviating phases of said center transmission disk and both side transmission disks by 180 degree, and in which distances between a center line in the axial direction of the outside periphery of the center transmission disk and both center lines in the axial direction of the outside peripheries of two sheets of both side transmission disks are substantially equal; and
fourthly, the eccentric orbiting type speed changing device, comprising a cylindrical casing, four sheets of transmission disks held in the casing separately in an axial direction and outside peripheries thereof rolling-contacting an inside periphery of the casing, and diameters thereof being smaller than an inner diameter of the casing, a carrier having a pillar-like portion passing through the transmission disks in the axial direction, and an eccentric rotating means which causes two sheets of center transmission disks of the same phases and two sheets of transmission disks of the same phases positioned at both sides of said center transmission disks to perform eccentric rotations under a condition of deviating phases of said center transmission disks and both side transmission disks by 180 degree, and in which distances between center lines in the axial direction of the outside peripheries of two sheets of center transmission disks and both center lines in the axial direction of the outside peripheries of two sheets of both side transmission disks are substantially equal.
When the speed reduction is carried out by the eccentric orbiting type speed changing gear device according to the first aspect of the invention, the pinions in mesh with the casing perform the eccentric rotation by an eccentric rotating means, and at this time, the gearing engagement in the Y axial direction (
Akin Gump Strauss Hauer & Feld L.L.P.
Fenstermacher David
Teijin Seiki Company Limited
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