Bearings – Rotary bearing – Antifriction bearing
Patent
1997-06-06
1998-09-01
Hannon, Thomas R.
Bearings
Rotary bearing
Antifriction bearing
F16C 2700
Patent
active
058000704
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention concerns a damping device for a rotatable shaft, which supports a centrifugal rotor and is journalled in a bearing in a frame in such a way that an oscillating movement of the shaft relative to the frame is admitted during the rotation of the centrifugal rotor, the damping device comprising at least a first friction member, which is connected to said bearing in such a way that the shaft is rotatable relative to the friction member, and a number of second friction members, which are supported by the frame and are distributed around the shaft, each one of the second friction members being arranged to be so kept pressed by a spring force towards the first friction member in a predetermined direction that upon oscillating movement of the shaft perpendicular to this predetermined direction a damping friction arises when the first friction member together with the shaft is moving relative to the second friction member referred to.
BACKGROUND OF THE INVENTION
Damping devices of this kind are common in vertical centrifugal separators, in which the centrifugal rotor is supported on one end of the shaft, especially if the centrifugal rotor rotates at a number of revolutions exceeding the first critical number of revolutions.
In such a damping device each one of the said second friction members is very carefully controlled in their movements in the said predetermined direction. Thus, the friction members referred to, which normally are designed as cylindrical pistons, are placed axially movable in cylindrical drilled holes and have a very accurate sliding fit in these holes. In a normal sliding fit between such pistons and the drilled holes the diameter of the holes is 0.01-0.1 mm larger than the outer diameter of the pistons. The part of the piston, the second friction member, which is pressed against the first friction member, and the part thereof, which is controlled by the drilled hole, are mostly designed in one piece but can also as shown in DE 132549 be designed as two separate parts fixedly joint together by means of a screw joint.
Instead of arranging the first friction member, as in these damping devices, in such a way that it is connected to the bearing and arranging the second friction members in a way such that they are supported by the frame one can also, as shown in the British patent publication 9002/1913, arrange the friction members inversely i.e. arrange the first friction member in a way such that it is supported by the frame and arrange the second friction members in a way such that they are connected to the bearing instead.
It has for long been a known problem in association with damping devices of the kind described above that they cause a great heat generation. This means that the bearing, which is connected to a friction member of the kind described above, has to be operating at a rather high temperature, which shortens the life of the bearing.
SUMMARY OF THE INVENTION
The object of the present invention is to reduce the heat generation caused by a damping device of the kind now in question.
This object can thanks to the invention surprisingly be accomplished in quite an easy manner, namely, by having each one of the second friction members movable relative to the element, which it is supported by or connected to, i. e. the frame or the bearing, perpendicular to the shaft and perpendicular to said predetermined direction in a limited distance, which at least is 0.2 mm.
The result of this movability of each one of the second friction members is that the damping device does not start to function as a damping device until the shaft performs oscillating movements in the area of the damping device exceeding 0.2 mm. Upon smaller oscillating movements it is true that the said second friction members will abut the first friction member, but they will only be entrained in this oscillating movement perpendicular to the shaft within the range of said distance without resulting in a relative movement between the same and the first friction member.
When
REFERENCES:
patent: 2487343 (1949-11-01), Kopf
patent: 2556317 (1951-06-01), Cook
patent: 3052166 (1962-09-01), Thrun
patent: 5088480 (1992-02-01), Radtke
Nilsson Sven-.ANG.ke
Sandblom Robert
Alfa Laval AB
Hannon Thomas R.
LandOfFree
Damping device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Damping device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Damping device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-262201