Field of Invention
The present invention relates to a device for measuring axial play for bearings,
specifically a device is used to measure axial play of Bali bearings installed in various
aggregates of airframe and control systems of an aircraft in assembled as well as in
. - Ag
loose condition.
Background of the invention
During overhauling of the aggregates of airframe components, control systems
elements, it is observed that there was large consumption of the bearings in last 05 year
and this result in shortage of availability of new bearings from the supplier.
After analyzing the data, the main causes of bearing rejection are (i) Functional failure,
(ii) Material defects, (iii) Improper mounting of bearings and (iv) Bearing life & health.
First three causes along with the sub-cau:.,=_es may be ruled out as the aggregates along
with the bearings have been under full functioning before they comes for overhaul and
came for overhaul after the completion of stipulated period of operation. Thes“?Ze facts
eliminate the possibilities of the problem due to such reasons. The remaining cause i.e.
bearinghealth may be the root cause as bearings are being life items in nature.
Concentrating on the bearing health as bearings are having the life and being the
life items, bearings should be monitored for the good health with the proper tests. The
causes, which affect the bearing, were analyzed and the same are (a) Jammed
movement, (b) Wear and tear, (c) Axial play and (d) Corrosion.
After detailed study, it was observed that maximum bearings got rejected due to
_ non—confirmation of axial play or axial play in doubt. The total of 83% rejection was due
to this reason. Being the vital cause, all the efforts were focused to confirmation of axial
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play.
While discussing about the axial play of bearings, to find out hidden causes for
non-confirmationof axial play of bearings in assembled units, many thoughts came
forward that leads toward the problem concern.
While moving towards the root cause of difficulty in quantifying the axial play, the
three basic causes along with sub causes are identified i.e. Man, Machine and Method.
Analyzing the possibility of man leading towards the problem it was revealed that as
Summary of the invention
there is lack of proper tool andmethod of quantifying the play the easiest method and
safe method is to replace the bearing to avoid the risk and as the play is judged by
manual method always subjective decisions were taken. Looking towards the cause due
to machine it was noticed that non availability of proper tools and device for checking,
wrong ‘method of load application improper way of holding the aggregates are leading
towards the replacement of bearing without proper quantification of play of bearing.
While attending the causes due to methods, the inadequate information and shop floor
methods and shortcuts are the major concern. All these causes pointing towa’.’ds the
non-' availability of suitable facilities to check and quantify the axial play of bearings in
assembled statejof units. Once the precise quantifying of axial play gets possible, it
becomes easy to segregate the acceptable units as per the stipulated standards. The
nucleus cause of the problem is‘ Non-availability of suitable device to check and
quantify the axial play of bearings that are assembled in aggregates.’ After fixing
the nucleus cause of the problem and being enlightened with the thinking of quantifying
the axial play, it is decided to go for design a device that serves for determining the axial
play.
The device should fulfill the following requirement —
— Should be able to accommodate any size & shape.
— Simple to operate.
— Should havehigh mobility'& Minimum accessories.
— Fool proof method & Acceptable to all.
— Should be able to satisfy all technological & design aspects.
— It should also be useful to check individual bearings prior to their use.
— It should not increase additional finance.
An object of the present invention is to provide a device for measuring axial play
for Ball bearing to check and measure axial play and based on checking further use of
Bali bearing for reliable operation of airframe aggregates and control systems
aggregates of an aircraft.
-1.
Object of the invention
a. Main object of the present invention is to design a device for measuring the axial
play for Ball bearings in assembled as well as in loose condition.
b. Check and ensure the axial play in the Ball bearing is within the acceptable limit
for further usage to ensure the reliable functioning of the systems.
Brief description of drawings (Refer Appendix-1) 4”
In the accompanying drawings:
FIG. 1 is an elevation view of the device;
A FIG. 2 is a details of basic structure the device illustrated in FIG. 1
FIG. 3 is a details in assembly;
Detailed description of the invention
The following discussion describes the clear understanding and embodiment of
A the invention. Detailed description of-the if-vention as follows-
Figure 1, 2 & 3 shows, an embodiment of the invention. The device comprises gyframe
pillar assembly 12, a bracketory assembly 2, weight assembly 15'; cam assembly 18
and cam handle 21 Frame 12 comprises a base plate 11 supported by base plates. On
base plate 11 bracketory assembly 2 is installed with the help of lug and dowel pin. At
both the edges pulley 3 is installed with the help of dowel pin. Paddle type weight
assembly rope 4 is passed through the groves of pulley 3.
To hold the aircraft control system component for which bearing axial play to be
checked is hold on the top plate 11 additional bracktrory arrangement comprising of
stopper 5 bolt nut 7 supporting bracket 8 and pivot assembly 9 and 10 for support to
the bracket8.
A
I
To apply alternate load on either side. by paddle type mechanism, cam assembly
17 is provided. Cam assembly comprises cam 18, cam housing 17, handle ‘rod 20",
I
handle 21, cam housing base 19. Cam handle 21 is an extension to handle rod 20. Cam
handle 21 is used to rotate cam 18 which are located in the cam housing 17. Two cams
4
18 are installed on cam handle 20 perpendicular to each other. ‘Pins 16 are installed on
the cam housing 17 to lift the weight by moving upwards due to movement ofeam -16
Load is applied through weight assembly 15 using cam handle 21. Due to load, inner
race of bearing gets pushes through rod inserted with wire 4 travels the available
clearance. This clearance is measured with the help of dial test indicator which is placed
on the plate.11.
Similarly load is applied on the other side and measure the travel of inner race
through rod using dial test indicator.
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The total travel measured is the axial play of the bearing.
We Claim:
1. A device for measuring the axial play for Ball bearings for airframe and
control system aggregates of an aircraft comprising top plate, frame,
bush sets, weight sets, load mechanism and DTI assembly,
2. A top plate supports the different shapes of aggregates,
3. Frame supports the top plate as claimed in the claim 2,
4. Bush sets of different diameters for holding outer and inner races of
bearings of different diameters,
5. Weight set to_ apply load on bearings for checking axial play with variable
loads,
6. DTI assembly for measuring the axial play which is result of application
of load and displacement of inner race with respect to outer race.