Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
2001-07-31
2003-07-01
Lavinder, Jack (Department: 3683)
Bearings
Rotary bearing
Antifriction bearing
C073S514390, C303S168000
Reexamination Certificate
active
06585420
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wheel support bearing assembly for use in an automotive vehicle or the like and including an electric generator that serves as a means for detecting the number of revolution for an anti-skid braking mechanism, and an anti-skid brake device using such wheel support bearing assembly.
2. Description of the Prior Art
An anti-skid brake device (ABS) is known as used for detecting the incipiency of a tire lock occurring on a low frictional road surface or at the time of a panic stricken braking so that braking can be relieved to secure a tire grip to thereby stabilize the steerability. A sensor for detecting the number of revolutions of wheel for detecting the incipiency of the tire being locked is provided in a wheel support bearing assembly. Generally a pulsar ring is provided at an end portion or the like of raceways in a bearing outside and a sensor portion is provided in face-to-face relation with the pulsar ring.
Also, as a wheel support bearing assembly having the sensor built therein, such a bearing assembly as shown in
FIG. 49
has hitherto been suggested, which includes a sensor portion
57
incorporated in a bearing outer race
51
which serves as a stationary member. See, for example, the Japanese Laid-open Utility Model Publication No. 1-156464. This prior art bearing assembly includes an outer race
51
for securement to a vehicle body structure, an inner race
52
mounted on a shaft portion of a hub wheel
54
, a plurality of rolling elements
53
interposed between the inner race
51
and the outer race
52
, and a sealing member
60
. The rotation sensor
55
is of a structure wherein the sensor portion
57
is inserted into a hole
58
defined in the outer race
51
so as to confront and align with the pulsar ring
56
provided in an outer peripheral surface of the inner race
52
. The use of the sensor built in the bearing assembly is effective to reduce the size of the wheel support bearing assembly as compared with the arrangement in which the pulsar ring and the sensor portion are disposed at the end of the bearing outside.
The prior art wheel support bearing assembly having built therein the sensor for detecting the number of revolutions of the wheel is such that detection signals generated by the sensor and supply of an electric power to the sensor are interfaced with the vehicle body structure by means of a wiring. In the prior art shown in
FIG. 49
, signal interfacing and supply of the electric power are carried out by means of an electric line
59
. As such, the prior art wheel support bearing assembly makes use of the electric wire for drawing a sensor output or the like, and this electric wire is exposed to the outside of the vehicle body structure at a location between the wheel support bearing assembly and the vehicle body structure. Because of this, the electric line is susceptible to breakage or the like by the effect of stones hitting and/or frozen snow within a tire housing. Also, in the case of a steering wheel, it is necessary for the electric wire to be twisted beforehand and often times a relatively large number of processing steps is required. The electric wire referred to above also requires sheathing thereof and, therefore, reduction in weight of an automotive vehicle tends to be hampered and, in view of the large number of steps of fixing the electric wire, a high cost tends to be incurred.
Also, although the conventional wheel support bearing assembly of the type in which the sensor is built therein as shown in
FIG. 49
can be assembled relatively compact, servicing of the rotation sensor
55
requires dismantling of the outer and inner races
51
and
52
of the wheel support bearing assembly, resulting in a problem that the servicing cannot be performed efficiently. For this reason, once the rotation sensor
55
fails to operate, the wheel support bearing assembly as a whole would be required to replace with a new one. In addition, although the conventional wheel support bearing assembly shown in
FIG. 49
is of the type wherein the rotation sensor is built therein, since a portion of the sensor portion
57
is exposed outside the bearing assembly, no sufficient reduction in size thereof is still achieved. Yet, the conventional wheel support bearing assembly shown in
FIG. 49
has a problem in that sealing of a hole
58
defined in the outer race
51
for receiving the sensor portion
57
is difficult to achieve, making it difficult to prevent any ingress of foreign matter.
In order to alleviate the foregoing problems, it may be contemplated to install the electric generator, which generates an electric power by relative rotation of the inner and outer races, within an annular space delimited between the inner and outer races, in combination with a wireless transmitting means for transmitting wireless a signal outputted from the electric generator and indicative of the number of revolutions of the wheel.
However, cable connection between the stator coil of the built-in electric generator and the wireless transmitting means positioned outside the bearing assembly requires a complicated and time-consuming wiring job, posing a problem associated with increase of the number of assembling steps. Also, a complicated and time-consuming procedure would also be required to seal a hole for passage of the cable.
Also, in an anti-skid brake device, the use of a magnetic coupling may be contemplated for the wireless transmission discussed hereinabove. In other words, magnetic communication may be used with no field emissive antenna. Where a feeble radio wave is used, it may be contemplated to amplitude modulate a carrier wave of a low frequency of about 2 MHz with a signal generated from the sensor.
However, in the case where the carrier wave is amplitude modulated with the feeble radio wave, external electromagnetic disturbances may often enter a receiver as an amplitude signal.
Where the wireless transmitting and receiving means is operable relying on the magnetic coupling, there is a problem that it tends to be adversely affected by up and down bumping of the wheel although there is little influence brought about by peripheral equipments.
Also, it may be contemplated to form the rotation sensor with the electric generator and also to use it as an electric power source for the wireless transmitting means. In such case, however, the electric power generated by the electric generator tends to decrease when the number of revolutions of the wheel decrease as a result of a braking force applied to the wheel, failing to sufficiently drive a transmitting circuit of the wireless transmitting means.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an improved wheel support bearing assembly having a capability of detecting the number of revolutions of a wheel, substantially free from wire breakage occurring outside a vehicle body, and capable of contributing to reduction in weight and cost of the automotive vehicle.
Another object of the present invention is to provide an improved anti-skid brake device wherein a detection signal indicative of the number of revolutions of the wheel can be transmitted and received wireless, and the possibility of wire breakage taking place outside the vehicle body is eliminated, and which is less sensitive to an influence brought about by noises and substantially free from an erroneous operation while allowing the automotive vehicle to be manufactured lightweight at a reduced cost.
A further object of the present invention is to provide an improved anti-skid brake device which is less sensitive to an influence brought about by peripheral equipments during wireless transmission and reception, and also to an influence which would be brought about by up and down bumping of the wheel.
According to one aspect of the present invention, there is provided a wheel support bearing assembly for rotatably supporting a wheel relative to an automotive body structure. This wheel support bearing assembly includes an outer mem
Hozumi Kazuhiko
Norimatsu Takayuki
Ohba Hiroaki
Ohtsuki Hisashi
Okada Koichi
Lavinder Jack
NTN Corporation
Pezzlo Benjamin
Sughrue & Mion, PLLC
LandOfFree
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