Gear cutting – milling – or planing – Milling – With means to control temperature or lubricate
Reexamination Certificate
2001-06-26
2003-07-29
Briggs, William (Department: 3722)
Gear cutting, milling, or planing
Milling
With means to control temperature or lubricate
C184S012000, C384S469000
Reexamination Certificate
active
06599066
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a rotating shaft apparatus for driving a spindle to which a tool or a workpiece is mounted or for driving feed screw shafts provided in X-, Y- and Z-orthogonal three axes, and a machine tool such as a milling machine, a machining center, a grinding machine, a lathe, an electric discharge machine. The invention relates to a novel technique which enhances the durability if the rotating shaft, such as a spindle or a feed shaft rotates at a high rotational speed.
BACKGROUND ART
In rotating shaft apparatuses having a spindle or feed shafts of a machine tool, bearings, for rotationally supporting the shaft, generate a heat due to the rotation of the rotating shaft. The heat is transmitted to the rotating shaft to increase the temperature of the rotating shaft, which results in a thermal deformation thereof. For example, a spindle apparatus which rotates at a high speed exhibits remarkably such a trend. Therefore, a liquid coolant for cooling the spindle and preventing the increase in the temperature thereof and a lubrication for the bearings for supporting the spindle are required to be effective and optimum. On the other hand, increase in feeding speed of the X-, Y- and Z-orthogonal three axes is also desired. Therefore, as in case of the spindle, a liquid coolant for cooling the feed shafts and preventing the increase in the temperature thereof and a lubrication for the bearings for supporting the feed shafts are required to be effective and optimum. In such a field of the art, there are the following prior art.
As a first prior art, Japanese Unexamined Patent Publication (Kokai) No. 63-62638 discloses lubricating apparatus for a machine tool having a vertical spindle. The apparatus executes a jet lubrication in which a lubricating oil in the form of a jet is directed to a rolling member provided between inner and outer races of a bearing for rotationally supporting a spindle through a lubricating oil supplying nozzle provided adjacent the bearing, the lubricating oil being supplied to the nozzle from a lubricating oil supplying apparatus provided outside of the spindle apparatus through a lubricating oil supplying conduit.
As a second prior art, Japanese Unexamined Patent Publication (Kokai) No. 61-16252 discloses a bearing lubricating apparatus. The apparatus executes an oil air lubrication in which a lubricating oil in the form of an aerosol is directed to a rolling member provided between inner and outer races of a bearing for rotationally supporting a spindle through a lubricating oil supplying pipe provided adjacent the bearing, the lubricating oil being supplied to the lubricating oil supplying pipe from a lubricating oil supplying apparatus provided outside of the spindle apparatus through a lubricating oil supplying conduit.
As a third prior art, Japanese Patent Publication No. 2541700 discloses a bearing lubricating apparatus. The apparatus executes an under-race lubrication in which a lubricating oil is directed, by centrifugal force due to the rotation of a spindle, to a rolling member provided between inner and outer races of a bearing through a passage provided in the inner race of the bearing, the lubricating oil being supplied to a lubricating oil supplying passage provided in the spindle along the axis thereof from a lubricating oil supplying apparatus provided outside of the spindle apparatus.
As a fourth prior art, Japanese Unexamined Patent Publication (Kokai) No. 4-57355 discloses a spindle apparatus. The apparatus executes another type under-race lubrication by a configuration different from the third prior art. The lubricating oil is directed, by centrifugal force due to the rotation of a spindle, to a rolling member provided between inner and outer races of a bearing through a passage provided in the inner race of the bearing, the lubricating oil being supplied to a lubricating oil supplying passage provided in a drawbar, inserted in the spindle for drawing a tool to the spindle, from a lubricating oil supplying apparatus provided outside of the spindle apparatus.
AS a fifth prior art, Japanese Unexamined Patent Publication (Kokai) No. 64-87130 discloses a spindle apparatus in which a liquid coolant flows through a spindle. The liquid coolant is supplied into a space, between a cavity formed in the spindle and a drawbar provided in the cavity, from a coolant source provided outside of the spindle apparatus to cool the spindle from its inside. The bearings for rotationally supporting is indirectly cooled by the liquid coolant.
As a sixth prior art, Japanese Publication No. 2677505 discloses a spindle apparatus. In this apparatus, a liquid lubricant is supplied into a space, between a cavity formed in the spindle and a drawbar provided in the cavity, or into a drawbar provided in the spindle for holding a tool to the spindle, from a lubricant source provided outside of the spindle apparatus to cool the spindle from its inside. Further, the lubricant is supplied, by the centrifugal force due to the rotation of the spindle, to the rolling members provided between inner and outer races of a bearing for rotationally supporting the spindle through a passage of the inner race to execute a under-race lubrication. The lubricant is further supplied to the housing to cool indirectly the outer race of the bearing and a built-in motor, thereafter the lubricant is recovered.
AS a seventh prior art, Japanese Unexamined Patent Publication (Kokai) No. 8-118199 discloses a feeding apparatus for a machine tool. In this apparatus, a liquid coolant is supplied into a cavity provided in a feed screw shaft from a coolant temperature adjusting apparatus provided outside of the feeding apparatus to cool the feed screw shaft from its inside. Further, the coolant is supplied, by centrifugal force generated by the rotation of the feed screw shaft, to the rolling members provided between inner and outer races of a bearing for rotationally supporting the feed screw shaft through a passage of the inner race to execute a under-race lubrication, thereafter the coolant is recovered.
In the jet lubrication of the first prior art, the liquid lubricant in the form of a jet is directed to the rolling member provided between the inner and outer races through a lubricant supplying nozzle. Therefore, special nozzle and liquid lubricant supply passage is required, which makes the configuration of the spindle apparatus complex. Further, since the liquid lubricant is supplied through a long lubricant supply passage, the liquid lubricant may be contaminated by a foreign particles, such as a dust so that the spindle is rapidly damaged by the foreign particles when the spindle rotates, in particular at a high rotational speed.
In the oil air lubrication of the second prior art, the liquid lubricant in the form of an aerosol is directed to the rolling member provided between the inner and outer races through the lubricating oil supplying nozzle. Therefore, as in the first prior art, special nozzle and liquid lubricant supply passage is required, which makes the configuration of the spindle apparatus complex. Further, since the liquid lubricant is supplied through a long lubricant supply passage, the liquid lubricant may be contaminated by a foreign particles, such as a dust so that the spindle is rapidly damaged by the foreign particles when the spindle rotates, in particular at a high rotational speed.
In the under-race lubrication of the third prior art, the liquid lubricant is supplied to the rolling member provided between the inner and outer races through the passage provided in the inner race by the centrifugal force due to the rotation of a spindle. According to the under-race lubricant, when the spindle rotates at a high rotational speed, for example above 20000 min
−1
, it is difficult to control the flow rate of the liquid lubricant supplied to the bearing by the effect of the centrifugal force due to the rotation of the spindle, and in some case, the increase in the amount of the lubricant supplied to the bearing results in the increase in
Inoue Shin'ichi
Koike Shinji
Briggs William
Makino Milling Machine Co., Ltd.
Paul & Paul
LandOfFree
Rotating shaft device and machine tool does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rotating shaft device and machine tool, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rotating shaft device and machine tool will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3058423