Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
2002-10-18
2004-12-14
Footland, Lenard A. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
Reexamination Certificate
active
06830379
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a rotation-speed sensor device and more particularly to a rotation-speed sensor device used for detecting the rpm of the wheels of an automobile.
The present invention relates to a double row rolling bearing with a sensor unit for rotatively supporting a wheel of a rolling stock or an automobile or a rotation shaft of a mill for metal working to a housing or a suspension system which does not rotate even at the time of use, and detecting a state of the double row rolling bearing portion. The double row rolling bearing with a sensor unit is effective for detecting a rotating speed of a wheel, a rotating shaft or the like, and a state of the double row rolling bearing (temperature, oscillation or the like) so as to judge existence/inexistence of error or abnormality of the double row rolling bearing portion.
2. Description of the Related Art
In order to control an anti-lock brake system (ABS) or traction control system (TCS) in order to maintain the stability and steadiness of an automobile when braking or accelerating, it is necessary to detect the rpm of the wheels. Recently, a rotation-speed sensor device is built into a rolling-bearing unit for supporting the wheels to rotate freely with respect to the suspension, and such a rolling bearing unit with rotation-speed sensor device is widely used for supporting the wheels such that they rotate freely with respect to the suspension and for detecting the rpm of the wheels.
A rolling-bearing unit with rotation-speed sensor device that is used for this purpose and having a structure as shown in FIG.
18
and
FIG. 19
is disclosed in Japanese Patent Publication No. Tokukai Hei 11-23596.
The first example of prior construction of a rolling bearing unit
1
with rotation-speed sensor device shown in
FIG. 18
comprises a rotation-speed sensor device
3
built into the rolling-bearing unit
2
. In the rolling-bearing unit
2
, a hub
5
and inner race
6
, which form a rotating race, are supported such that they rotate freely on the inner-diameter side of an outer race
4
, which is the stationary race. A first flange
7
for attaching to the wheel is formed around the outer peripheral surface on the outside end of this hub
5
(which is the end on the outside in the width direction when installed in the vehicle, and is the left end in all of the drawings of the rolling-bearing unit. This is the same throughout the explanation of this invention), and a first inner-ring raceway
8
is formed around the outer peripheral surface in the middle of the hub
5
.
Moreover, the inner race
6
has a second inner-ring raceway
9
formed around its outer peripheral surface and located at a portion closer to the inside end of the hub
5
(which is the end on the inside in the width direction when installed in the vehicle, and is the right end in all of the drawings of the rolling-bearing unit. This is the same throughout the explanation of this invention) and it fits around a stepped section
10
that has a diameter a little less than that of the section where the first inner-ring raceway
8
is formed. Also, a first outer-ring raceway
11
that faces the first inner-ring raceway
8
, and a second outer-ring raceway
12
that faces the second inner-ring raceway
9
are formed around the inner peripheral surface of the outer race
4
, and a second flange
13
for supporting the outer race
4
on the suspension is formed around the outer peripheral surface of the outer race
4
.
Moreover, a plurality of rolling elements
14
are located between the first and second inner-ring raceways
8
,
9
and the first and second outer-ring raceways
11
,
12
, and they support the hub
5
and inner race
6
such that they rotate freely on the inner-diameter side of the outer race
4
. With the inner race
6
fitted around the stepped section
10
, a nut
15
screws onto a male screw section that is formed on the inside end of the hub
5
and retains the inner race
6
in order to prevent the inner race
6
and hub
5
from coming apart.
Furthermore, a cover
16
covers the opening on the inside end (right end in
FIG. 18
) of the outer race
4
. This cover
16
comprises a main piece
17
that is cylindrical shaped with a bottom and that is formed by injection molding of synthetic resin or plastic, and a metal cylindrical fitting section
18
that is connected to the opening section of the main piece
17
. This cylindrical fitting section
18
is connected to the opening section of the main piece
17
by molding its base end at the time when the main piece
17
is being formed by injection molding. This cover
16
, formed in this way, covers the opening on the inside end of the outer race
4
by securely interference-fitting the tip end half (left half in
FIG. 18
) of the cylindrical fitting section
18
around the inside end of the outer race
4
.
On the other hand, the encoder
19
of the rotation-speed sensor device fits around the outer peripheral surface of the inside end of the inner race
6
, which fits around the inside end of the hub
5
, in the section that is separated from the second inner-ring raceway
9
. This encoder
19
comprises a support ring
20
and permanent magnet
21
. Of these, the support ring
20
is formed into a circular ring shape having an L-shaped cross section by bending a magnetic metal sheet such as SPCC, and it interference-fits tightly around the inside end of the inner race
6
.
Also, the permanent magnet
21
is made by attaching rubber, which has been mixed with ferrite powder or the like, to the inside surface of the circular ring portion of the support ring
20
by burn-in etc. This permanent magnet
21
is magnetically oriented in the axial direction (left and right in FIG.
18
), and the direction of magnetic poles alternates at equal intervals around in the circumferential direction. Therefore, the S pole and N pole are arranged such that they alternate at equal intervals around the circumference of the inside surface of the encoder
19
, which is the detected section.
Moreover, an insertion hole
22
is formed in the main piece
17
of the cover
16
in the part that faces the inside surface of the permanent magnet
21
of the encoder
19
such that it penetrates the main piece
17
in the axial direction of the cover
16
. A sensor
23
is inserted inside this insertion hole
22
. This sensor
23
comprises: an IC, having a magnet-detection element such as a hall element or magnetic-resistance element (MR element), whose characteristics change according to the direction of flow of magnetic flux, and a wave-shaping circuit for adjusting the waveform output from this magnet detection element; and a pole-piece made of magnetic material for guiding the magnetic flux output from the permanent magnet
21
(or flowing to the permanent magnet
21
) to the magnet detection element, which are embedded in synthetic resin or plastic.
This kind of sensor
23
is formed at a portion closer to the tip end (left end in FIG.
18
), and it comprises: a column-shaped insert section
24
that can be snugly inserted inside the insertion hole
22
, and an outward facing flange-shaped edge section
25
that is formed around the base end (right end in
FIG. 18
) of the insert section
24
. There is a fitting groove formed around the outer peripheral surface in the middle of the insert section
24
and an O-ring
26
fits in this fitting groove.
On the other hand, a fitting cylinder
28
is formed through part of the outside surface of the cover
16
(the surface that is on opposite side from the space
27
where the rolling elements
14
are located, or the right side surface in
FIG. 18
) in the section around the opening of the insertion hole
22
. When the insert section
24
is inserted inside the fitting cylinder
28
and the flange-shaped edge section
25
comes in contact with the tip end surface of the fitting cylinder
28
, the sensor
23
is connected to and supported by this fitting cylinder
28
by a fitting spring
29
. A connection and support
Endo Shigeru
Miyazaki Hiroya
Morita Kouichi
Nakamura Yuji
Sakamoto Junshi
Footland Lenard A.
Katten Muchin Zavis & Rosenman
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