US2014144558A1PendingUtilityA1
Bearing component and method for surface hardening
Est. expiryJul 2, 2030(~3.9 yrs left)· nominal 20-yr term from priority
Inventors:Marco Burtchen
C21D 1/10C21D 1/42Y02P10/25C21D 9/40C21D 9/36C21D 2221/10
30
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Claims
Abstract
Bearing component having a surface at least one part of which has been surface hardened by induction heating. A cross section of the bearing component through said surface exhibits a hardness H surface at said surface, and remains substantially equal through a first region, a hardness H core at the non-hardened core of the bearing component and remains substantially equal through a third region and a transition, second region spanning between the first and third regions. The average hardness in the first region of the harness profile is Y 1 and the average hardness in the third region of the harness profile is Y 3 and the hardness profile in the second region has a section defined as a line between the points where 0<k<2, on the hardness profile. The hardness of said section of said second region decreases on average by less than 50 HCR per mm.
Claims
exact text as granted — not AI-modified1 . A bearing component having a surface, wherein at least one part of said surface has been surface hardened by induction heating,
whereby a cross section of the bearing component through said surface exhibits a hardness H surface at said surface and a hardness H core at the non-hardened core of the bearing component, wherein the hardness profile of said cross section exhibits: a first region whose hardness is substantially equal to the hardness H surface at said surface, a third region whose hardness is substantially equal to the hardness H core at the non-hardened core of the bearing component and a second region between said first and third regions, wherein the hardness profile in the first region has an average hardness and the hardness profile in the third region has an average hardness Y 3 , and whereby if a line is drawn on the hardness profile in said second region between the points
Y
1
+
Y
3
2
+
(
Y
1
-
Y
3
4
)
*
k
and
Y
1
+
Y
3
2
-
(
Y
1
-
Y
3
4
)
*
k
,
where 0<k<2, the hardness of said bearing component in said second region determined along said line decreases by less than 50 HRC per mm.
2 . The bearing component according to claim 1 , characterized in that the hardness of said bearing component in said second region determined along said line decreases by one of:
less than 30 HRC per mm, less than 25 HRC per mm, less than 20 HRC per mm, and less than 15 HRC per mm.
3 . The bearing component according to claim 1 , wherein said hardness H surface at said surface is between 55-75 HRC.
4 . The bearing component according to claim 1 , wherein the hardness H core at the non-hardened core of the bearing component is between 15-30 HRC.
5 . The bearing component according to claim 1 , wherein said first region extends from the surface to a depth of up to 6 mm below said surface.
6 . The bearing component according to claim 1 , wherein said bearing component is formed into one of an inner ring, an outer ring and a rolling element.
7 . The bearing component according to claim 1 , wherein said bearing component is integrated into at least part of a rolling element bearing, a roller bearing, a plain bearing, a bushing, a journal bearing, and a sleeve bearing.
8 . A method for surface hardening at least part of the surface of a bearing component, the method comprising steps of:
heating said at least one part of the surface with an electromagnetic induction coil to at least a ferrite/austenite transformation temperature by induction heating, maintaining said at least one part of said surface at said at least a ferrite/austenite transformation temperature in order to allow for sufficient heat transport below the surface resulting in a sufficient austenitization of the at least one part, and immediately quenching said at least one part of the surface in order to obtain a cross section of the bearing component through said surface which exhibits a hardness H surface at said surface and a hardness H core at the non-hardened core of the bearing component, wherein the hardness profile of said cross section exhibits: a first region whose hardness is substantially equal to the hardness H surface at said surface, a third region whose hardness is substantially equal to the hardness H core at the non-hardened core of the bearing component and a second region between said first and third regions, wherein the hardness profile in the first region has an average hardness Y 1 , and the hardness profile in the third region has an average hardness Y 3 , and whereby if a line is drawn on the hardness profile in said second region between the points
Y
1
+
Y
3
2
+
(
Y
1
-
Y
3
4
)
*
k
and
Y
1
+
Y
3
2
-
(
Y
1
-
Y
3
4
)
*
k
,
where 0<k<2, the hardness of said bearing component in said second region determined along said line decreases by less than 50 HRC per mm.
9 . The method according to claim 8 , wherein said hardness of said bearing component in said second region determined along said line decreases by at least one of:
less than 30 HRC per mm, less than 25 HRC per mm, less than 20 HRC per mm, and less than 15 HRC per mm.
10 . The method according to claim 8 , further comprising a step of maintaining said at least one part of the interior surface at said temperature for one of:
at least 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, 60 seconds, 70 seconds, and greater than 70 seconds.
11 . The method according to claim 8 , further comprising a step of generating said hardness profile of said cross section that exhibits:
a first region whose hardness is substantially equal to the hardness H surface at said surface, a third region whose hardness is substantially equal to the hardness H core at the non-hardened core of the bearing component and a second region between said first and third regions in which the hardness profile exhibits a smooth transition between the hardness of said first and third regions.
12 . The method according to claim 11 , wherein said first region extends from the surface to a depth of up to 6 mm below said surface.
13 . The method according to claim 8 , further comprising a step of forming said bearing component into any one of: an inner ring, an outer ring and a rolling element.
14 . The method according to claim 8 , further comprising a step of integrating said bearing component into one of a rolling element bearing, a roller bearing, a plain bearing, a bushing, a journal bearing and a sleeve bearing.
15 . The bearing component according to claim 1 , wherein the hardness H surface at said surface is between 58-63 HRC.
16 . The method according to claim 11 , wherein said first region extends from the surface to a depth of 1-4 mm below said surface.Join the waitlist — get patent alerts
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