Bearings – Rotary bearing – Antifriction bearing
Patent
1988-06-06
1989-07-04
Werner, David
Bearings
Rotary bearing
Antifriction bearing
384474, 310 90, F16C 314, H02K 5173
Patent
active
048446254
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a structure of a journal bearing for a motor, particularly to a structure of a journal bearing by which a channel for supplying an oil-air mix lubrication medium and a drain channel can be easily arranged within a motor operating at high revolutionary speeds.
BACKGROUND ART
Recently, the spindle of a machine tool must be able to rotate at a very high speed, and thus conventionally, a motor for rotating at a medium speed is used and an increased revolutionary speed is obtained by using a transmission mechanism and thus the spindle is driven at a high revolutionary speed.
Nevertheless, problems arise such as a time lag in the revolution of the spindle when the revolution speed of the spindle is changed, and so on, whereby the finishing accuracy of a workpiece is reduced. Therefore, a spindle motor directly connected to the spindle of a machine tool is required, and thus a journal structure capable of enduring a high revolutionary speed becomes necessary. A journal bearing under a conventional grease lubrication becomes overheated at a high revolutionary speed such as represented by the value Dmn, which is obtained by multiplying an average diameter of an inner diameter and an outer diameter of the journal bearing by the rotational speed, and is substantially equal to or more than one million (for example, where the average diameter is 50 mm and the rotational speed is twenty thousand r.p.m.), and normal driving cannot be maintained. Therefore, an oil-air mix lubrication which supplies air containing an oil mist is needed.
Although the oil-air mix lubrication is needed for a normal driving of a motor at high revolutionary speeds, as described hereinafter, it is difficult to provide a channel for supplying an oil-air mix and a drain channel for a complex oil-air mix lubrication in a conventional journal bearing structure mounted in a onepiece type motor housing.
DISCLOSURE OF THE INVENTION
Accordingly, an object of the present invention is to provide a journal bearing structure for a motor operating at a high revolutionary speed, wherein a channel for supplying an oil-air mix and a drain channel are easily arranged, thus solving the above problems.
In view of the foregoing object, the present invention provides a journal bearing structure for a motor operating at a high revolutionary speed, characterized in that each inner portion of a front housing and a rear housing of a motor is constructed in such a way that it can be separated from the remaining outer portion and can be assembled. A channel for supplying an oil-air mix and a drain channel are provided on each inner portion of the front housing and the rear housing. A journal bearing is mounted in each central side of the inner portion of the front housing and the inner portion of the rear housing. Each inner portion in which the journal bearing is mounted is inserted and set onto an output shaft of the motor, to thus act as a journal bearing structure using an oil-air mix in which the output shaft rotates and to serve as portions of the front housing and the rear housing, respectively. According to the above mentioned journal bearing structure, the housing portions for sustaining the front and rear journal bearings of the motor can be separated from the remaining housing portion of the motor and be machined, and therefore, a complex channel for supplying an oil-air mix, and a drain channel, which are needed for the journal bearing of the motor operating at a high revolutionary speed, can be easily provided.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal sectional view of a motor operating at a high revolutionary speed and having the journal bearing structure according to the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described in more detail hereinafter according to the embodiment shown in the attached drawing. An output shaft 14 having a rotor 12 fixed thereto is supported rotatively at the front and rear portions thereof by a front jo
REFERENCES:
patent: 2242268 (1941-05-01), Ray
patent: 2770506 (1956-11-01), Derner
patent: 2986433 (1961-05-01), Herrmann
patent: 3612631 (1971-10-01), O'Connor
patent: 3940191 (1976-02-01), Tomioka et al.
Katsuzawa Yukio
Masuya Michi
Eghtessad John M.
Fanuc Ltd.
Werner David
LandOfFree
Structure of journal bearing for motor operating at high revolut does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Structure of journal bearing for motor operating at high revolut, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Structure of journal bearing for motor operating at high revolut will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-849387