Gear cutting – milling – or planing – Milling – Process
Patent
1995-09-19
1998-03-10
Howell, Daniel W.
Gear cutting, milling, or planing
Milling
Process
82106, 409199, B23C 306
Patent
active
057253390
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a method of machining a crankshaft which is utilized for an engine or the like.
In the prior art, outer peripheral surfaces of a pin, a journal, and a side surface of a counter weight of a crankshaft of the above kind are worked by means of a crankshaft mill. However, both end portions of the pin and the journal are worked by means of another machine because these end portions are formed with R grooves which are subjected to undercut working.
The use of another machine for forming the R-grooves involves increased equipment costs and includes additional steps for changing a setup at a time of attaching and detaching the work. The prior art arrangement is therefore inconvenient and results in reduced productivity.
In order to overcome the defects associated with the prior art, a machining method has been proposed which is capable of simultaneously working the outer peripheral surfaces and the R grooves of the pin and the journal. The method includes mounting, to the same cutter, a tip for working the outer peripheral surfaces and a tip for working the R grooves. The above arrangement is based on an assumption that the side surface of the counter weight is not worked or shaped such as in a case where high-speed revolution of the crankshaft is not required.
However, in a case involving high-speed revolution of the crankshaft and thus requiring working of the side surface of the counterweight, the side surface of the counter weight will be worked by the same tip as that utilized for the working of the R groove. As a result, the tip for forming the R groove is subject to greater wear, resulting in degradation of the working performance of the crankshaft.
SUMMARY OF THE INVENTION
An object of the present invention is to avoid the inconveniences described above, and to provide a method of machining a crankshaft capable of effectively working both the outer peripheral surfaces and the R grooves of a pin and a journal by using a single working machine.
In order to achieve the above object, according to the present invention, there is provided a method of machining or working a crankshaft which includes a first cutter for simultaneously working an outer peripheral surface of a pin or journal of the crankshaft and a side surface of a counter weight disposed adjacent to the outer peripheral surface of the pin or journal. The cutter is mounted to one of two cutter heads of a crankshaft mill. A second cutter is provided for forming an R groove on the pin or the journal. The second cutter is mounted to another one of the cutter heads. The outer peripheral surface of the pin or the journal and the side surface of the counter weight adjacent to the outer peripheral surface are simultaneously worked by the first cutter, and thereafter, the R groove is formed on the pin or the journal by the second cutter.
According to the working method, the outer peripheral surfaces of the pin and journal of the crankshaft, the side surface of the counter weight, and the R grooves of the pin and the journal can be worked by a single working machine, so that changes of the machine setup are not required, thus improving the productivity of the process of machining the crankshaft. In addition, the outer peripheral surface of the pin or the journal is worked by a cutter which is different from the cutter for working the R groove, so that the wear of the cutter for the R groove working is reduced, thus improving the R groove working precision.
Preferably, in a case where the crankshaft is provided with a plurality of pins and journals, the outer peripheral surfaces of the plurality of pins or journals and the side surfaces of the counter weights disposed adjacent to the outer peripheral surfaces can be worked respectively simultaneously and then successively, and the R groove working is performed on the pins and journals, of which the outer peripheral surfaces have been worked, successively.
Furthermore, preferably, the outer peripheral surface of one of the pin and the journal and
REFERENCES:
patent: 4269551 (1981-05-01), Kialowetz
patent: 4309134 (1982-01-01), Schmid
patent: 4790698 (1988-12-01), Heffron
Howell Daniel W.
Kabushiki Kaisha Komatsu Seisakusho
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