Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
2001-12-28
2003-07-22
Hannon, Thomas R. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
Reexamination Certificate
active
06595692
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rotation sensor-equipped bearing and particularly it relates to an outer ring rotation stop construction.
2. Brief Description of the Prior Art
Detection of rotational speed (rpm) of a bearing has heretofore been made by installing a rotation sensor in close vicinity to the bearing. Recently, however, for the sake of facilitation of installation and effective use of space, rotation sensor-equipped bearings with a rotation sensor fixed to the bearing have been proposed.
A conventional example of such rotation sensor-equipped bearing will be described with reference to the drawings. FIG.
2
(A) is a front view of the rotation sensor section, which is the principal portion of a rotation sensor-equipped bearing, and FIG.
2
(B) is a sectional view thereof.
In
FIG. 2
, the numeral
21
denotes a bearing comprising an inner ring
22
, an outer ring
23
, a plurality of rolling elements
24
rollably disposed between the inner and outer rings
22
and
23
, and a cage
25
for rollably receiving said rolling elements
24
at a predetermined pitch. The outer diameter portion of said outer ring
23
is mounted to the inner diameter portion of a bearing housing
26
. The numeral
27
denotes rotation sensor comprising an encoder
28
, such as a magnetic encoder, fixed to said inner ring
22
, a core metal
29
mounted to said outer ring
23
, a sensor housing
30
fixed to said core metal
29
, a sensor
31
fixed within the sensor housing
30
, a circuit board
32
having a circuit incorporated therein for processing electric signals obtained by the sensor
31
, an electric wire
33
for taking the detected rotational speed (rpm) from the circuit board
32
, wherein the sensor
31
, circuit board
32
, the connected end of electric wire
33
, etc., within said sensor housing
30
are molded with resin. Further, a hold-down lid
34
is attached to a bearing housing
26
by fixing members
35
such as machine screws at a plurality of circumferential places. The electric wire
33
is taken out to the outside through a notch groove
34
a
formed in the hold-down lid
34
.
And, when the inner ring
22
rotates, the encoder
28
mounted to this inner ring
22
rotates with the inner ring
22
and concomitantly therewith its position relative to the sensor
31
periodically changes, whereby the sensor
31
detects the rotational speed (rpm) of the inner ring
22
, the detected rotational speed (rpm) being taken out as an electric signal to the outside by the electric wire
33
.
However, in the conventional rotation sensor-equipped bearing described above, since the outer ring
23
is mounted by fitting in the bearing housing
26
, the difference in thermal expansion between the outer ring
23
and the bearing housing
26
, and other factors cause the clearance between the outer diameter of the outer ring
23
and the inner diameter of the bearing housing
26
to exceed the allowable limit, so that with the rotation of the inner ring
22
, the outer ring
23
sometimes rotates along the direction of rotation of the inner ring
22
. If the outer ring
23
should rotate, the sensor housing
30
mounted to the outer ring
23
will simultaneously rotate, resulting in a shearing force being applied to the electric wire
33
taken out of the sensor housing
30
since the latter is taken out to the outside through the notch groove
34
a
formed in the hold-down lid
34
fixed to the bearing housing
26
. Therefore, in extreme cases, the electric wire
33
sometimes breaks.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a rotation sensor-equipped bearing, such as the one described above, having a rotation stop construction for the outer ring capable of preventing the rotation of the outer ring and the breakage of the electric wire when the outer ring tends to rotate.
A rotation sensor-equipped bearing described in claim 1, for solving said problem, comprises an inner ring, an outer ring, a plurality of rolling elements received between said inner and outer rings, said inner ring constituting a rotatable raceway ring, an encoder mounted to one end of said rotatable raceway ring, said outer ring being mounted to the bearing housing to constitute a fixed raceway ring, a sensor mounted to said fixed raceway ring in a position opposed to said encoder through a core metal, and a hold-down lid fixed to said bearing housing, said rotation sensor-equipped bearing being characterized in that the outer diameter surface of a sensor housing receiving said sensor is provided with a rotation stop member radially projecting through said core metal, said rotation stop member being disposed in a notch groove in said hold-down lid.
Thus, providing the outer diameter surface of the sensor housing receiving the sensor with the rotation stop member radially projecting through said core metal and disposing the rotation stop member in the notch groove in said hold-down lid ensures that even if a turning force is produced in the bearing outer ring, the disposition of the rotation stop member in the notch groove in the hold-down lid results in the rotation stop member abutting against the inner wall surface of the notch groove in the hold-down lid, thereby reliably preventing the rotation of the bearing outer ring. Simultaneously, since the rotation stop member serves as a fixing member for the electric wire, the pull-out strength of the electric wire is improved, thus preventing the breakage of the electric wire.
A rotation sensor-equipped bearing of the invention is characterized in that the rotation stop member is integral with the sensor housing.
Thus, this construction in which the rotation stop member is integral with the sensor housing eliminates the possibility of the rotation stop member rotating relative to the sensor housing and makes it possible to omit the operation of attaching the rotation stop member to the sensor housing.
A rotation sensor-equipped bearing of the invention is characterized in that the rotation stop member is separate from the sensor housing member and is attached to said sensor housing member.
Thus, this construction in which the rotation stop member is separate from the sensor housing member and is attached to said sensor housing member allows separate fabrication of the rotation stop member and sensor housing, so that as compared with the case of constructing the rotation stop member to be integral with the sensor housing member, fabrication molds are simplified and so is the production, and moreover, even if the rotation stop member or the sensor housing member should be partly damaged and discarded, discarding the whole of the rotation stop member and sensor housing member is saved.
REFERENCES:
patent: 4946295 (1990-08-01), Hajzler
patent: 5143458 (1992-09-01), Alff et al.
patent: 5594334 (1997-01-01), Sonnerat et al.
patent: 6043643 (2000-03-01), Message et al.
patent: 6094046 (2000-07-01), Message et al.
patent: 6338576 (2002-01-01), Girardin et al.
Arent Fox Kintner Plotkin & Kahn
Hannon Thomas R.
NTN Corporation
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