DESCRIPTION
Title of the Invention: Rolling bearing apparatus
Technical Field
f0001| The present invention relates to a rolling bearing apparatus, and more
particularly, to a rolling bearing apparatus for use at a roll neck of a rolling mill.
Background Art
[0002] Conventionally, bearing apparatuses arc used for fkc purpose of supporting a roil
neck part, which is a shaft portion of a mill roll. In such bearing apparatuses, the mill
roll is gradually worn while steel sheets are rolled, and therefore, it is necessary to
frequently replace (he mill roil. Aecordingly, the bearing and (he roll neek pari are
attached to each other with a predetermined filling clearance between them, in a so-called
loose nt manner. Thus, there has been a problem that a slippage occurs between an
inner ring of the bearing and (he roll neck part during operation of the mill roll, resulting
in wear of the roll neck part having a lower hardness. In order- fo prevent tliis slippage,
as shown in Jig. 5, a first key groove 62 is formed on one end face of an inner ring 61,
and a second key groove 64 is formed on an outer peripheral face of a roll neck part 63,
One end of a fii"st key 65 is inserted into and kicked to the first key groove 62, and an
L-shaped other end of the first key 65 is inserted into and engaged with the second key
gioove 64. As a result, a relative slippage (called as "a creep'') between the inner ring
61 and the roll neck parJ 63 is prevented at one side of (he inner ring 61, and wear of the
roll neck part 63 having a lower hardness as compared with the inner ring 61 can be
prevented {see, e.g.. Patent Document 1).
[0003] In a conventional creep preventing rolling bearing apparatus 71, as shown in lHig.
6, by providing a cutout groove in a part of an inner ring 72 in an axial direction of a
rolling hearing 76, (here is formed a key groove 73 opened at an inner peripheral lace 72i
and at an outer peripheral face 72o of the inner ring 72. A second key groove 73r is
formed on an outer peripheral face 77o of a rotation shaft 77 along an axial direction f.
Hy aligning the first key groove 73 and the second key groove 731 and inserting a key 78,
a creep between the inner ring 72 and the relation slvaft 77 is prevented (hereinafter,
referred to as "an open type rolling bearing").
£0004] In another conventional creep preventing rolling bearing apparatus 81, as shown
in Fig. 7, Intrusion of foreign matters irom the exterior is prevented by providing a seal
89 for tight sealing on an outer side of a rolling bearing 86. To seal an internal space
between an outer ring 85 and an inner ring 82 from outside the bearing, an outer
peripheral face 89o of the seal 89 is fitted and fixed to an axial end portion of an inner
peripheral face 85i oT [he outer ring 85, and a lip 89i oT the seal 89 is arranged to be in
sliding contact with an outer peripheral face 82o of the inner ring 82. To prevent the lip
89i ofthe seal 89 from contacting a Til's! key groove 83 of Ihe inner ring 82, the firs! key
gntove 83 is located axially inward of the inner ring 82 with respect to the seal 89,
(hereinafter rcicrrcd to as "a seated rolling bearing").
Prior Ait Document
Patent Document
[0005J Patent Document 1;JP02-148704 U
Summary of the Invention
Problems that the Invention is lo Solve
[flflfttil Tn the conventional sealed lolling bearing as described above, the seal 89 is
provided in the axial end portion of the rolling bearing S6. Accordingly, the axial length
Ls of a rolling element 84 of the sealed roiling bearing needs to be made shorter as
compared with the axial length Ixs of a rolling element 74 of the open type rolling bearing
not provided with a seal. Therefore, there is a problem that a basic dynamic load rating
is remarkably lowered.
10007| Here, the "basic dynamic load raiing" means a load not varying in direction and
amount and which makes the rated fatigue life one million rotations, with a condition that
the inner ring 72, 82 is nikiled and the outer ring 75, 85 is fixed.
|LHJOS] According lo Patent Document 1, to increase a contact area of the first key 65,
the inner ring 61 is extended so thai an end face ofthc inner ring 61 protrudes in the axial
direction than a seal unit 68, and the first key groove 62 is formed by cutting a portion of
the one end face ofthc inner ring 6 i . Accordingly, stress concentration may occur at an
edge part of the first key groove that is cut out. Moreover', for the purpose of ensuring
the basic dynamic load rating, a portion for providing tlie first key groove 62 had to be
provided in the inner ring 61, which hinders downsizing of the entire bearing,
|0009] The present invention has been made in view of the problems above described,
and it is an object ihercoT to provide a creep preventing rolling liearing apparatus in
which stress concentration at a key groove can be relieved while ensuring the basic
dynamic load rating.
Means for Solving the Problems
fOOIO]
The invention is directed to a rolling bearing apparatus comprising:
a rolling bearing comprising an outer ring, an inner ring having a first key
groove fonned along an axial direction on an inner peripheral face of an axial end portion
oT Ihc inner ring, and a plurality of roiling elements held between the inner ring and the
outer ring in a tollable manner;
a rotation shall liaving a second key groove on an oulcr peripheral face thereof*
on which the rolling bearing is incorporated; and
a key inserted into tlie first key groove and the second key groove,
characterized in that the first key groove is opened at the inner peripheral face of
the inner ring in the axiaf end portion of the inner ring, and
the first key groove is formed so as Lo have :i predeteiTnined length in the axial
direction from the axia! end portion of tfie inner ring at a position having a certain depth
from an outer peripheral face of the inner ling in a ladial direction.
Advantage of the Invenlion
10011] According lo Ihe present invention, il is possible to provide a creep preventing
lolling bearing apparalus in which stress concentration at the key groove can be relieved
while ensuring lite basic dynamic load rating.
Brief Description of the Drawings
[0012] FJg. 1(a) is a vertical sectional view illustrating a main portion of a scaled tolling
bearing apparatus according to a first embodiment of the present invention, and Fig. 1(b)
is a cross sectional view illustrating a key structure of the sealed rolling bearing apparatus
of 1% 1(a);
Fig 2 is a pei speed ve view ofa rotation shad shown in Figs. 1(a) and 1(b);
Fig. 3(a) is a verliea! sectional view illustrating a main portion oTa sealed rolling
hearing apparatus according to a second embodiment of the present invenlion, and Fig.
3(b) is a cross sectional view illustrating a key structure of the sealed rolling bearing
apparatus of Fig, 3{a);
I'ig, -1(a) is a vertical sectional view illustrating a main portion of a sealed roiling
bearing apparatus accoi'ding to a thud embodiment of the present invention, *>"d l'igr 4(b)
is a cross sectional view illustrating a key structure of the sealed rolling hearing apparatus
of Pig. 4(a);
Fig. 5 is a vcrlieal sectional view illustrating a main portion or a conventional
bearing apparalus ibr a rolling mill;
Fig. 6 is a vertical sectional view illustrating a main portion of a conventional
rolling beating apparatus; and
I'ig, 7 is a vertical sectional view illustrating a main portion of another
conventional rolling bearing apparalus.
Embodiments of the Invention
[0013] HcreinaAer, with reference to the drawings, respective embodiments of the
present invention will be described. A first embodiment is an example in which a key
and a key groove have a wedge shape, a second embodiment is an example in which a
key and a key groove have a prism shape, and a thin! embodiment is an example in which
a key has a cylindrical shape and a key groove has a shape of a semicircular groove,
[0014] (hirst Embodiment)
Fig. 1(a) is a vertical sectional view illustrating a main portion ora scaled rolling
bearing apparatus 11 according to (he first embodiment of (he present invention, and Fig.
1(b) is a cross sectional view illustrating a key structure of the scaled rolling bearing
apparatus 11 ofFig. 1(a).
[0015] As shown in Fig. 1(a), the scaled rolling bearing apparatus 11 includes a rolling
bearing 16 having an inner ring 12 provided with a first key groove 13 in its axial end
portion 12t, a plurality of rolling elements 14 held on an outer peripheral face 12o of the
inner ring 12 in a roIIable manner, and an outer ring 15 provided with a raceway face for
the mlling elements 14 on its inner peripheral face 15i. The sealed rolling hearing
apparatus 11 further includes a rotation shall 17, and a key 18. The rotation shah 17 on
which the rolling bearing 16 is incorporated is provided with a second key groove 13' on
its outer peripheral face 17o. The key IS is inserted in a state in winch the first key
groove 13 and the second key groove 13h are aligned.
[0016] The first key groove 13 is provided in the axial end portion 12tof the inner ring
12 and is opened at an inner peripheral face 12i, The fiist key groove 13 is formed so as
to have a predoleiinined length L in (he axial direction from the axial end portion 12t of
the inner ring 12 at a position having a certain depth D from the outer peripheral fate 12o
in a radial direction. The lirst key groove 13 has a substantially quadrangular cross
section. The end of the first key groove 13 is obliquely cut. A seal 19 for tight scaling
js provided on an outer side oT the rolling bearing 16 for (he purpose of preventing
intrusion of foreign matters.
|(lftl71 Fig. 2 is a perspective view of the rotation shall shown in Figs. 1(a) and 1(b).
As shown in Fig. 2, the second groove 13f in a shape of an angular groove is provided on
the outer peripheral face 17o of the rotation shaft 17 along the axial direction. As
shown in Figs. 1(a) and 1(b), by aligning the first key gioove 13 provided in the inner
ring 12 and the second key groove 13' provided in the rotation shaft 17, a continuous key
groove having a wedge shape is formed. By inserting the key 18 having a wedge shape
into this key groove, the first key groove 13 and the seeond key groove 13r are fixed at
the same time.
[00 IS] According to the scaled rolling bearing apparatus II of (he first embodiment, Ihc
first key groove 13 opened at The inner peripheral face 12i is provided in the axial end
portion 121 of the inner ring 12 of the roiling bearing 16, and the second key groove 13'
contiguous with the first key groove 13 is provided on the outer peripheral face 17o of the
rotation shaft 17 along the axial direction, 'Jlie key 18 having the shape of a wedge is
insetted into and engaged with the key groove formed by aligning the |iositions of the
fiist key gioove 13 and the second key groove 13r. As a result, the first key groove 13
formed hi the inner ring 12 and the second key groove 13' formed in (he rotation shall 17
are fixed at the same time, and thus, a creep between the inner ring 12 and the rotation
shafl 17 can be prevented.
[0019] Moreover, according to the sealed rolling bearing apparatus 11 of the first
embodiment the first key groove 13 having a shape of a substantially angular groove is
formed so as to have the pitdeleiinined length L in the axial direction from the axial end
portion I2t of the inner ring 12 at the position having the certain depth D from the outer
peripheral face 12o of (he inner ring 12 in (he radial direction. As a result, a force
exerted on an edge part of flic first key groove 13 is dispersed, and therefore, it is possible
lo relieve stress at the key groove as com[>ared with the conventional creep preventing
roiling bearing apparatus 71,
[0020] (Second embodiment)
Fig. 3(a) is a vertical sectional view illustrating a main portion of a scaled rolling
bearing apparatus 21 according to the second embodiment of the present invention, and
Fig. 3(b) is a cross sectional view illustrating a key structure of the sealed rolling bearing
apparatus 21 of Fig. 3(a). Those parts corresponding to the preceding drawings ate
denoted with the same reference numerals, and descriptions thereof will be omitted,
[0021] As shown in Figs, 3(a) and 3(b), a first key groove 23 is provided in an axial end
portion 22t of an inner ring 22 and is opened at an inner peripheral face 22i. The first
key gi'oove 23 is fonned so as to have a predetermined length L in (he ax.ial direction
from tlie axial end portion 22t of the inner ring 22 at a position having a certain depth D
from an outer peripheral face 22ti in a radial direction. The lirsl key groove 23 has a
substantially quadrangular cross section. A seal 19 for tight scaling is provided on an
outer side of a rolling bearing 26 for the purpose of preventing intrusion of foreign
matters.
[0022] Like in the first embodiment, as shown in Fig. 2, the second groove (3' in a
shape of an angular groove is provided on the outer peripheral face l7o of the rotation
shaft 17 along tlie axial direction. As shown in Figs. 3(a) and 3(b), a continuous key
groove in a shape of an angular groove is hintied, by aligning (he first key groove 23
provided in the inner ring 22 and (he second key groove 13' provided hi the rotation shaft
17. By inserting a key 18 having a quadrangular prism shape into this key groove, the
first key groove 23 and the second key groove 13' are fixed at the same time,
Jfl023[ According to (he scaled rolling bearing apparatus 21 of the second embodiment,
the first key groove 23 opened at the inner peripheral face 22i is provided in the axial end
portion 22t of the inner ring 22 of the Killing bearing 26, and the second key groove 13'
contiguous wilh the fiisl key groove 13 is provided on (he outer peiiphcral face 17o ofthe
rotation shall 37 along the axial direction. The key 28 having the quadrangular prism
shape is inserted into and engaged with the key groove formed by aligning positions of
the first key groove 23 and the second key groove 13'- As a result, the first key groove
23 formed in the inner ring 22 and the second key groove 13* formed in the rotation shaft
17 are fixed at the same time, and thus, a creep between the inner ring 22 and the rotation
shaft 17 can be prevented,
[(I024J Moreover, according to the sealed rolling hearing apparatus 21 of the second
embodiment, ihe first key groove 23 having a shape of a substantially angular groove is
fanned so as to have the predetermined length L in the axial direction from the axial end
portion 221 of (lie inner ring 22 at the position having the certain depth D from the outer
peripheral face 22o of the inner ring 22 in the radial direction. As a result, a force
exerted on an edge part of the first key groove 23 is dispersed, and therefore, it is possible
to enhance the basic dynamic load rating, as compared with the conventional creep
preventing rolling bearing apparatus in which the key groove is formed by culling a part
of an end portion of Ihe inner ring extended in an axial direction oT Ihe bearing.
[01)25] (third embodiment)
Fig. 4(a) is a vertical sectional view illustrating a main portion of a sealed rolling
bearing apparatus 31 according to a third embodiment of the present invention, and Fig.
4(b) is a cross sectional view illustrating a key structure of the sealed rolling bearing
apparatus of Fig. 3(a), Those pails corresponding to the preceding drawings are denoted
with the same reference numerals and descriptions thereof will he omitted,
lflf}2(ij As shown in Fig. 4, a first key groove 33 is provided in an axial end portion 32t
of an inner ring 32 and is opened at an inner peripheral face 32i. The firsl key groove
33 is formed so as to have a predetermined length L in the axial direction from the axial
end portion 32t of the inner ring 32 at a position having a certain depth D from an outer
peripheral face 32o hi a radial direction. The first key groove 33 has a substantially
semiciicular cross section. A seal 19 Tor tight sealing is provided on an outer side ofa
rolling bearing 36 for the purpose of prevent tag intrusion of foreign matters.
[G027] AssSwyttfl inVigs, 4(a) and 4(b), a EGte^von stvdft 7 k provided with a sccos*d key
groove 33' on its outer peripheral face 37o along an axial direction (hereof, The second
key groove 33' has a substantially semicircular shape in section. A continuous key
groove having a circular section is foimed, by aligning (he first key groove 33 provided
in the inner ring 32 and the second key groove 33f provided in (he rotation shaft 37. Hy
inserting a key 3S having a cylindrical shape into this key groove, the first key groove 33
and the second key groove 33' arc fixed al (he same time,
ffl028l According to the scaled rolling bearing apparatus 31 of the third embodiment,
the Iirst key groove 33 opened at the inner peripheral face 32i is provided in the axial end
portion 32l of the inner ring 32 of the rolling bearing 3<*, and the second key groove 33r
contiguous with (ho first key groove 33 is provided on the outer peripheral face 37o of the
rotation shaft 37 along the axial direction, Ifte key 38 having (he cylindrical shape is
inserted into and engaged with the key groove formed by aligning positions of the first
key groove 33 and the second key groove 33'. As a result, the iirst key groove 33
foiyned in the inner ring 32 and the second key groove 33' formed in the rotation shaft 37
are fixed at the same time, and thus, a creep between the inner ring 32 and the rotation
shaft 37 can be prevented,
[0029] Moreover, accoitfing to the scaled rolling bearing apparatus 31 of the third
embodiment, the Iirst key groove 33 is formed so as to liave the predetermined length L
in the axial direction from (he axial end portion 32t of the inner ring 32 at the position
having the certain depth D from the outer peripheral face 32o of the inner ring 22 in the
radial direction* As a result, a force exerted on an edge part of the first key groove 33 is
dispersed to the cylindrical surface, and therefbi'e, ie is possible to relieve stress at (he
first key groove 33.
[0030} While embodiments and examples of the present invention have been described
above, the present invention is not limited to the embodiments described above, and can
be implemented with various modifications within a scope defined by Ihe claims. The
present application is based on Japanese Patent Application No. 2G12-78686 filed on
March 3, 2012, (ho content of which is incorporated herein by reference.
Description of Ihc Reference Signs
J0031J 11, 21, 31 Creep preventing rolling bearing apparatus
16, 26, 36 Rolling bearing
12,22,32,72,82 Inner ring
13,23, 33 1'irstkey groove
13', 33' Second key groove
11, 74,84 Rolling element
15, 85 Outer ring
17,37 Rotation shall
IS, 28, 38, 78 Key

CLAIMS
1. A rolling heaving apparatus comprising:
a rolling hearing comprising an miter ring, an inner ring having a first key
groove formed along m\ axial direction on an innerperipheral faeeol'an axial end portion
of the inner ring: and a plurality of rolling dements held between (he inner ring and the
outer ring in a reliable manner;
y rotation shaft having a second key gmove on an outer peripheral face (hereof
on which the rolling hearing is incorporated- and
a key inserted into the Just key groove and (he second key groove,
characterized in that the first key groove is opened at the inner peripheral faee of
the inner ring in (he axial end pottion oflhe inner ring, and
the firsl key groove is formed so as to have a predetermined length in the axial
direction from (he axial end portion of the inner ring at a position having a certain depth
from an outer peripheral face of the inneiL ring in a radial direction.