Abrading – Machine – Combined
Reexamination Certificate
1999-10-19
2001-11-13
Banks, Derris H. (Department: 3723)
Abrading
Machine
Combined
C451S066000, C451S073000, C451S057000, C451S058000, C451S037000, C072S053000, C029S090700
Reexamination Certificate
active
06315646
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a processing system for increasing the quality of a gear, which can efficiently and economically produce a gear of high quality by sequentially subjecting a gear to shot peening and barreling after tooth-forming by hobbing, shaving or rolling and surface hardening such as heat treatment, carburizing or nitriding, or gear surface grinding, so as to enhance dedendum bending fatigue strength, surface durability and abrasion resistance, thereby increasing load capacity.
The present invention can be applicable to any of various gears fabricated in the conventional processes (for example, a spur gear, a helical gear, a double helical gear, a crossed helical gear, a worm gear and the like), and further, is applicable not only to a normal involute form, but also arbitrary tooth forms (for example, a cycloidal curve, a trochoidal curve, a circular arc and the like).
2. Description of the Related Art
A conventional basic series of processes of fabricating a steel gear, which has been subjected to surface hardening such as carburization hardening, includes three kinds of typical processes described below. Here, there will be omitted shot blasting for the purpose of scaling or deburring after the surface hardening or center hole grinding for the purpose of fixing the gear to a shaft.
(1) Hobbing→surface hardening
(2) Hobbing→shaving or rolling→surface hardening
(3) Hobbing→surface hardening→tooth surface grinding
The series (1) of processes, in which a tooth surface is finished only by hobbing, is used in fabricating a relatively large gear for, e.g., a water gate. The series (2) of processes is used in fabricating a small- or middle-sized gear, which is usually used in a transmission for an automobile. The series (3) of processes is used in fabricating a gear for use in a transmission for a prestige car or a speed changer for general industrial machinery.
Nowadays, after the series (2) or (3) of processes, shot peening may be additionally performed for the purpose of enhancement of dedendum bending fatigue strength of the gear. However, if a dedendum is subjected to shot peening, a tooth surface for power transmission becomes rough, thereby arising a problem from the viewpoint of surface durability.
The inventor of the present invention has found that barreling after shot peening can remarkably improve surface durability. In view of this finding, the inventor has devised a basic series of processes as follows:
(4) Hobbing→shaving or rolling→surface hardening→shot peening→barreling
(5) Hobbing→surface hardening→tooth surface grinding→shot→peening→barreling
However, in the series (4) of processes, the shot peening and the barreling are generally performed independently of each other, thereby arising a problem that efficient production cannot be achieved. Moreover, also in the series (5) of processes, the tooth surface grinding, the shot peening and the barreling are generally performed independently of each other, thereby arising the problem that efficient production cannot be achieved. Furthermore, both a shot peening apparatus and a barreling apparatus are relatively liable to induce environmental pollution, thus arising a problem of an increase in cost of cleaning of working environment by means of a dust collecting apparatus or the like.
SUMMARY OF THE INVENTION
The present invention has been accomplished in an attempt to solve the above problems observed in the related art. An object of the present invention is to take the processes of shot peening and barreling into one and the same system so as to perform the processes in sequence, thus achieving efficient production. Furthermore, it is another object of the present invention to take tooth surface grinding into one and the same system so as to achieve more efficient production. Additionally, it is a further object of the present invention to reduced the cost of cleaning the working environment. Furthermore, it is still further object of the present invention to provide a barreling apparatus which can be used in the system.
According to the present invention, there is provided a processing system for increasing the quality of a gear in which the above-described problems can be advantageously solved. A processing system for increasing the quality of a gear, after tooth forming and surface hardening, comprises: a shot peening apparatus for subjecting, to shot peening, a gear after tooth forming and surface hardening; a barreling apparatus positioned adjacently to the shot peening apparatus, for subjecting, to barreling, the gear which has been subjected to the shot peening by the shot peening apparatus; and a gear feeding apparatus positioned adjacently to the shot peening apparatus and the barreling apparatus for feeding, to the barreling apparatus, the gear which has been subjected to the shot peening by the shot peening apparatus.
In this system, when a workpiece comprising a jig detachably supporting one or a plurality of gears is, after tooth-forming and surface hardening, fed to the shot peening apparatus, the jig rotates the gear while it is shot peened so as to improve the dedendum bending fatigue strength of the gear. Subsequently, the gear feeding apparatus positioned adjacent both shot peening apparatus and the barreling apparatus feeds the jig and detachably supported gear, which gear has been subjected to shot peening by the shot peening apparatus, to the barreling apparatus, which then subjects the fed gear to barreling by rotating the jig and supported gear inside a revolving barrel tank.
Consequently, according to the system, the shot peening and barreling processes take place in one and the same system, the gear feeding apparatus moving the jig and gear from the shot peening apparatus to the barreling apparatus so that a gear of high quality can be efficiently produced. Furthermore, since both the shot peening apparatus and the barreling apparatus, both of which are relatively liable to induce environmental pollution, are integrated with each other, the number of cleaning facilities such as dust collecting apparatus can be reduced, thus achieving inexpensive cleaning of the working environment.
In a processing system for increasing the quality of a gear according to the present invention, the gear feeding apparatus may feed the jig supporting detachably the gear to the shot peening apparatus and may take the jig supporting detachably the gear out of the barreling apparatus. According to the system, the gear can be automatically fed to or taken out of the system, thus efficiently producing a gear of high quality.
Furthermore, in a processing system for increasing the quality of a gear according to the present invention, the shot peening apparatus and the barreling apparatus may be positioned laterally with respect to each other. According to the system, the feeding distance of the gear can be reduced, thus simplifying the configuration of the gear feeding apparatus.
Meanwhile, in a processing system for increasing the quality of a gear according to the present invention, the shot peening apparatus and the barreling apparatus may be positioned vertically with respect to each other. According to the system, the floor area occupied by the system can thereby be reduced, thus enhancing the space efficiency of the gear production site.
Moreover, a processing system for increasing the quality of a gear according to the present invention may further comprise: a grinding apparatus positioned adjacently to the shot peening apparatus, for grinding the tooth surface of the gear; and a second gear feeding apparatus positioned adjacently to the grinding apparatus and the shot peering apparatus, for feeding, to the shot peening apparatus, the gear whose tooth surface has been ground by the grinding apparatus. According to the system, the gear surface grinding before the shot peening can be taken into one and the same system so as to be performed in sequence, thus more efficiently
Banks Derris H.
Frank Robert J.
Nguyen G.
Saga University
Venable
LandOfFree
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