The influence of technological factors upon the accuracy and quality of the cold plastic deformation revolution surfaces.
Carausu, Constantin ; Pruteanu, Octavian ; Sarbu, Ionel 等
1. INTRODUCTION
The cold-working of the ball-bearing races'bed bearers,
especially cyclical with balls and cyclical with cylindrical rollers, is
actually an innovation for the bearing industry in Romania.
Experimental research has showed the way in which working
parameters of special technological equipments have an influence upon
the roughness and ovality, i.e. upon the quality parameters of surfaces
processed by means of cold plastic deformation (Wagoner & Chenot,
2001), (Lupescu et all, 2004).
2. EXPERIMENTAL CONDITIONS
2.1 Material and half-finished
We have used for the experiment the steel 100Cr6, specially
designed for ball-bearing races, which has a good cold-workability and
hot-workability, as well as cutting workability. The blank was a
ball-bearing race, which was hot-formed and processed by turning, boring
and facing, until the dimensions of the blank corresponded to those
established in the technical documentation of SC Rulmenti SA Barlad.
2.2 Working Equipment
For the cold-working of the outer races' bed bearers of the
bearing 6207 we have used the Japanese equipment CRF-120 OR which allows
the variation of the deformation force, P, of the deformation feed, A,
and of the tool's rotation speed, V.
The working diagram is shown in fig. 1.
[FIGURE 1 OMITTED]
2.3 Instrumentation
The roughness of surfaces was measured with the device
Taylor-Hobson, and the shape deviations with the device Perthometer
Marsurf CD 120.
3. EXPERIMENTAL RESULTS
3.1 The Influence of the deformation force, P
Table 1 shows the results of out tests. Each value represents the
average of five measurements (Pruteanu et all, 2006).
We infer from the table that the prameters' minimal values
have been obtained for the deformation force P= 6.5 Mpa. Fig. 2 shows
the graphical representation of the variation of the bed
bearers'roughness and ovality varying with the deformation force
(Pruteanu et all, 2007).
3.2 The influence of the deformation feed, A
Table 2 shows the results of our tests. The parameter values
represent the average of five measurements.
[FIGURE 2 OMITTED]
We infer from the table that the minimal value for the shape
deviation are obtained for A= 34 mm/min, while the minimal roughness
will be obtained at an feed of 30 mm/min. Due to the fact that the
roughness difference compared to that calculated for A= 34 mm/min is
only of 0.01 um, we have chosen this value for the deformation feed.
Fig. 3 shows the graphical representation of the variation of the
bed bearers'roughness and ovality varying with the deformation
feed.
We infer from the table that the minimal values for shape
deviations will be obtained for the speed V= 95 rpm, while the minimal
roughness of 0.41 um will be obtained for V= 80 rpm.
Due to the fact that the difference compared to that for V= 95 rpm
is of only 0.03um and that the value 0.44 um is bellow the value
stipulated in the technical documentation for a normal functioning of
bearings, we have recommended for processing the value V= 95 rpm.
Fig. 4 shows the graphical representation of the bed bearers'
roughness and ovality, varying with the tool's speed of rotation.
3.3 The influence of the tool's rotation speed, V Table 3
shows the results of our tests. The parameters values represent the
average of five measurements.
[FIGURE 3 OMITTED]
[FIGURE 4 OMITTED]
4. CONCLUSION
From the parameters' variation range on the testing machine,
we have determined the values for which we can obtain the best technical
conditions for the ball-bearing races'bed bearers:
* The deformation force value P= 6,5 MPa ensures for all parameter
values- roughness and ovality--the best values;
* The deformation feed value A= 34 mm/min ensures minimal values
for shape deviation--ovality--as well as values acceptable within the
framework of technical conditions imposed for the normal functioning of
bearings to ensure the roughness of the bed bearers.
* The tool's rotation speed value V = 95 rpm ensures minimal
values for the shape deviation and acceptable values for the bed
bearers' roughness.
We will extend ours research to other bearings. Likewise, we will
analyze the influence of the work parameters upon the circularity.
5. REFERENCES
Lupescu, O., Carausu, C., Lupescu Ov. (2004). Structural
modification of the OLl 37 steel to superficial plastic distorsion
processing at cold through rolling, Bul. Inst. Pol. Iasi, Tomul L (LIV),
Fasc V a, 213-216.
Pruteanu ,O.V., Carausu, C. Paraschiv, Dr., Sarbu, I., (2006). The
influence of the working parameters on the parameters of the superficial
layer when procesing the steels through grinding in the rolling's
technology. [TEXT NOT REPRODUCIBLE IN ASCII] Minsk, Belarus, may,
186-197.
Pruteanu, O.V., Paraschiv, Dr., Pricope, C., Bunea, C.M., Sarbu,
I., Carausu, C. (2007). Considerations Regarding the 100Cr6
Material's Conduct through the cold Rolling of the Bearing Rings,
International Journal for Manufacturing Science & Technology, U.S.
Library of Congress, vol. 9, no.1, p.51-57, ISSN 1524-1548.
Pruteanu, O.V., Paraschiv, Dr., Carausu, C., Sarbu, I., Bunea, M.,
Bardac, D. (2007). Processing through plastic deformation of the bearing
rings. MicroCAD 2007, International Scientific Conference, Miskolc,
143-148.
Wagoner, R.H., Chenot, J.L. (2001). Metal forming analysis.
Cambridge University Press. New York.
Table 1. The Influence of the deformation
force, PA = 34 mm/ min, S = 95 rot/ min
P Ra Ovality
[MPa] [[mu]m] [mm]
5.5 0.39 0.30
6.0 0.44 0.27
6.5 0.41 0.15
7.0 0.43 0.22
Table 2. The influence of the deformation
feed P = 6.5 Mpa, S = 95 rpm
A [R.sub.a] Ovality
[mm/min] [[mu]m] [mm]
27.5 0.46 0.27
30 0.41 0.20
32 0.45 0.24
34 0.42 0.18
Table 3. The influence of the tool's rotation
speed P = 6,5 Mpa, A = 34 mm/ min
V Ra Ovality
[rpm] [[mu]m] [mm]
80 0,41 0,27
85 0,44 0,25
90 0,42 0,24
95 0,44 0,18