Machine element or mechanism – Control lever and linkage systems – Multiple controlling elements for single controlled element
Reexamination Certificate
2001-07-10
2004-05-04
Fenstermacher, David (Department: 3682)
Machine element or mechanism
Control lever and linkage systems
Multiple controlling elements for single controlled element
C074S490070
Reexamination Certificate
active
06729201
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a traction drive speed reducer including a circumscribed axis, a plurality of intermediate axes arranged contacting around the outer periphery of the circumscribed axis, and an inscribed cylinder inscribing the outer periphery of the intermediate axis.
The present invention also relates to a conveyance apparatus using, as a drive apparatus, a traction drive speed reducer including a circumscribed axis, a plurality of intermediate axes arranged contacting around the outer periphery of the circumscribed axis, and an inscribed cylinder inscribing the outer periphery of the intermediate axes.
The present invention also relates to an arrangement of the 2-axis output encoder in an conveyance apparatus.
2. Related Art
(1) In a traction drive speed reducer including a circumscribed axis, a plurality of intermediate axes arranged contacting around the outer periphery of the circumscribed axis, and an inscribed cylinder inscribing the outer periphery of the intermediate axes, the traction drive speed reducer in which the rotation of the drive motor is inputted into the circumscribed axis, and the intermediate axes is rotatably supported by the supporting member, and the output is taken from the supporting member, is well known (for example, JP-A-58-119746).
However, in the conventionally well known traction drive speed reducer, when there is a dispersion in the diameter of a plurality of intermediate axes, the rotation center of the supporting member from which the output is taken out can not corresponds with the center of the circumscribed axis. Therefore, the nonuniformity of the rotation occurs in the output taken from the supporting member, which is disadvantageous.
That is, in the conventional traction drive speed reducer, the rotation force from the drive motor is inputted into the circumscribed axis, in contrast to that, the output is taken from the supporting member supporting the intermediate axes. In this case, when the center of the inscribed cylinder is dislocated due to the dispersion of the diameter of a plurality of intermediate axes, the rotation center of the output is rotated around the original rotation center with the radius corresponding to the dislocated amount, therefore, the rotation of the output side causes the variation due to the dislocation of the rotation center.
Accordingly, an object of the present invention is to provide a traction drive speed reducer free from the afore-mentioned problem.
(2) In a field in which a fine processing inhibiting a particle, such as in a semiconductor wafer, or LCD (liquid crystal display) glass base, is necessary, the conveyed material can not be conveyed (can not hold) by chucking (grasp the conveyed material). Therefore, as the handling method in such the conveyance field, it is the present condition that the conveyance is conducted by a conveyance apparatus of a system in which the conveyed material is only put (only supported) on the hand (end effector) section.
However, in such the conveyance apparatus, in the support, there are an organic (such as the rubber, or the like) support, and an inorganic (ceramic, or the like) support, and there is a problem that, although the organic support has the comparatively large frictional force, it can not be used in the high temperature portion. Further, there is a vacuum absorption system, however, although it can be used in the air, it can not be used in the vacuum which is desirably used at the time of processing of the semiconductor wafer, or the LCD (liquid crystal display) glass base. Further, in the vacuum absorption method, the structure is complicated and the cost is high.
Accordingly, in many cases, the conveyed material (wafer, or the like) is held only by the frictional force with the hand support section. However, when such the conveyed material is suddenly moved, or moved while being vibrated, the conveyed material is slid and dislocation is caused, and the disadvantages such as the generation of the particle positioning failure, and the damage of the conveyed material, occur. Therefore, for the conveyance apparatus used in such the accurate conveyance field, the conveyance apparatus by which the conveyance with the extremely small vibration (acceleration) can be conducted (smooth conveyance), is required.
In such the conveyance apparatus in which the particle is inhibited and the fine processing is necessary, such as the semiconductor wafer or LCD (liquid crystal display) glass base, conventionally the direct drive (DD) system drive apparatus is used (JP-A-3-281183). However, in the DD system drive apparatus, because the output density (torque/volume, torque/motor capacity) is small, there is a problem that the drive apparatus is large, and the power source capacity becomes also large.
On the one hand, in order to aim at the compactification of the drive apparatus, there is also a conveyance apparatus using a speed reducer having a gear mechanism. By using the speed reducer having the gear mechanism, the compactification of the drive apparatus can be possible. However, because the gear is provided, there is a problem that the backlash exists, or vibration or noise is generated. Further, in order to reduce the vibration or noise, in the conveyance apparatus using the speed reducer having the gear mechanism, the control becomes complicated, and the cost is high.
Accordingly, another object of the present invention is to provide a conveyance apparatus by which the problems accompanied to the above conventional technology can be solved, and by which the traction drive speed reducer is used for the drive apparatus, and a compact and low vibration•low noise conveyance apparatus by which the semiconductor wafer or LCD (liquid crystal display) glass base is processed.
(3) In the conveyance apparatus used in a field which inhibits a particle and requires an accurate processing, such as a semiconductor wafer or LCD (liquid crystal display) glass base, it is well-known that an optical encoder is arranged in the vacuum (for example, JP-W-8-506771 (U.S. Pat. No. 5,720,590)).
In the conveyance apparatus disclosed in this JP-W-8-506771, because an encoder or bearing is provided in the vacuum atmosphere, the use of the high cost encoder or bearing for the vacuum atmosphere specification is necessary. Further, because the bearing is used in the vacuum atmosphere, when the load capacity is desired to be increased, it is a cause of the particle generation, therefore, there is a problem that the load capacity can not be increased.
Accordingly, yet another object of the present invention is to provide an arrangement of a 2-axis output encoder in a simply structured conveyance apparatus.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, the problems accompanied to the conventional art is solved by a traction drive speed reducer which comprises a circumscribed axis, a plurality of intermediate axes arranged contacting around the outer periphery of the circumscribed axis, and an inscribed cylinder inscribing the outer periphery of the intermediate axes, wherein a supporting member to rotatably support the intermediate axes is fixed, a drive motor is connected to at least one of the plurality of intermediate axes, and an output is taken from the circumscribed axis having the larger diameter than the outer diameter of the intermediate axis.
In the present invention, the rotation is inputted into the intermediate axis, and the output is taken from the circumscribed axis located at the center. That is, the output axis which is the circumscribed axis, is set at the rotation center of the reference output, and the supporting member is fixed. According to this structure, even when there is the dispersion of the diameter in a plurality of intermediate axes, because the inscribed cylinder which is a free condition, allows the deformation due to the dispersion of the diameter of the intermediate axes, its rotation center is simultaneously dislocated. As the result, the variation of the rot
Maekawa Takahiro
Mori Hiroki
Okuno Chohei
Watanabe Tetsuya
Akin Gump Strauss Hauer & Feld L.L.P.
Fenstermacher David
Teijin Seiki Co. Ltd.
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