JP4569363B2 - Rolling bearing device with sensor - Google Patents

Description

  The present invention relates to a rolling bearing device with a sensor in which a rolling bearing and a sensor device for detecting various information thereof are integrated.

In automobiles, various information is necessary to perform the control. Therefore, a fixed-side track member fixed to the vehicle body side, a rotation-side track member to which wheels are attached, and two members disposed between the two members. It has been proposed to provide a sensor device in a hub unit (rolling bearing) having rows of rolling elements. For example, Patent Document 1 discloses that the rotational speed is obtained by providing a magnetic impedance sensor on the fixed-side track member and providing an annular pulsar ring facing the sensor on the rotation-side track member. The pulsar ring is made by kneading about 80-98% by weight of ferrite into rubber and magnetizing the north and south poles alternately.
JP 2004-294145 A

  According to the rolling bearing device with a sensor of the above-mentioned Patent Document 1, there is a problem that the rubber kneading equipment is easily painful because a process of magnetization is necessary when manufacturing the pulsar ring and a large amount of ferrite needs to be kneaded into the rubber. In addition, there is a problem that the accumulated error of the pitch between the magnetized S pole and N pole is large.

  An object of the present invention is to provide a sensor-equipped rolling bearing device capable of obtaining rotation information without providing a pulsar ring on a rotation side raceway member.

A rolling bearing device with a sensor according to the present invention is a rolling bearing device with a sensor provided with a rolling bearing having a stationary race member, a rotating race member and a rolling element, and a sensor device. The sensor device is a stationary race member. An ultrasonic sensor that detects a rolling element load as an echo ratio, and a processing unit that obtains a rotational speed from the output of the ultrasonic sensor. The ultrasonic sensor includes a plurality of ultrasonic sensors arranged at a predetermined pitch. The plurality of vibrators are arranged at an equal pitch, and the pitch of the vibrator × the number of vibrators = one pitch of the rolling element is characterized.

  The ultrasonic sensor obtains the reflected echo of the ultrasonic wave by receiving the reflected wave of the ultrasonic wave output from the vibrator, and when the load acting on the rolling element is large, the contact area becomes large, The reflected wave becomes smaller.

  It is preferable that the transducers of the ultrasonic sensor have an equal pitch along the circumferential direction of a circle concentric with the rolling bearing. Further, instead of the equal pitch, the interval between adjacent vibrators may be shifted by a fixed increment.

  According to a plurality of vibrators arranged at equal pitches, when one rolling element passes through the ultrasonic sensor, a signal (pulse number signal) equal to the number of vibrators is output, thereby improving the decomposition performance. To do.

  A rolling element load is calculated | required from the echo ratio obtained by the following formula | equation, for example.

Echo ratio = 100 × (H0−H1) / H0
H0: Echo intensity when the rolling element is separated from the ultrasonic sensor by a half pitch H1: Echo intensity when the rolling element is located immediately below the ultrasonic sensor The ultrasonic sensor is, for example, a cylinder in which a screw part is formed on the outer periphery. A case-like case and a plurality of vibrators arranged in the case, and the screw portion of the case is screwed into the bottomed female screw portion provided in the stationary race member, A predetermined preload is set at the tip of the case. When the fixed-side track member is supported by a housing or the like, the ultrasonic sensor may be held by the housing or the like so that the contact surface between the fixed-side track member and the housing or the like may be faced.

  When the rotating side raceway member rotates and the rolling element revolves along with this, the output of the ultrasonic sensor increases each time the rolling element passes. Therefore, the processing means can determine the revolution speed of the rolling element, that is, the rotational speed of the rotating side raceway member by counting the number of output increases / decreases (number of pulses) and performing an appropriate calculation.

  Between the ball revolution speed Nc of the ball bearing and the rotation speed of the race (inner ring rotation speed: Ni, outer ring rotation speed: Ne), the ball diameter is d and the ball set pitch diameter (PC .D.) Is D and contact angle is β, and there is a relationship of Nc = {(Ne + Ni) + (Ne−Ni) dcosβ / D} / 2. It can be easily converted into the rotation speed of the member (wheel).

  Further, when the load acting on the rolling bearing changes, the magnitude of the echo ratio changes due to this load change. Since the relationship between the echo ratio and the load acting on the bearing can be obtained in advance, the load acting on the rolling bearing can be obtained from the echo ratio by previously obtaining this relationship experimentally. Therefore, the processing means is further provided with a load calculation unit for obtaining a load acting on the rolling bearing from the output of each ultrasonic sensor, so that not only the rotation speed but also the rolling speed can be obtained by one type of sensor (ultrasonic sensor). The load acting on the bearing can also be obtained.

  The number of ultrasonic sensors is not limited to one, and two or more ultrasonic sensors may be provided at a predetermined interval.

  When a plurality of vibrators are arranged at an equal pitch, it is preferable that the pitch of the vibrators × the number of vibrators = one pitch of the rolling elements. One pitch of the rolling elements may be based on an angle (1 pitch of the rolling elements = 360 ° / number of rolling elements), or may be based on a circumferential length (1 pitch of the rolling elements = P. CD / number of rolling elements).

  In this way, the decomposition performance can be optimized.

  According to the sensor rolling bearing device of the present invention, the rotational speed of the rotation-side raceway member can be obtained by performing a suitable calculation by counting the number of pulses accompanying the revolution of the rolling element by a plurality of vibrators arranged at a predetermined pitch. Therefore, rotation information can be obtained without providing a pulsar ring on the rotation side raceway member.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 show an embodiment of a rolling bearing device with a sensor according to the present invention. In the following description, the left and right refer to the left and right in FIG. Note that the left is inside the vehicle and the right is outside the vehicle.

  This sensor-equipped rolling bearing device is used as a sensor-equipped hub unit, and includes a hub unit (1) and a sensor device (2).

  The hub unit (1) is arranged in two rows between the fixed side track member (3) fixed to the vehicle body side, the rotary side track member (4) to which the wheel is attached, and both members (3) and (4). A ball (5), which is a plurality of rolling elements, and a cage (6) for holding each row of balls (5) are provided.

  The fixed side raceway member (3) has an outer ring (fixed ring) function of the bearing, and includes a cylindrical part (12) in which two rows of outer ring raceways are formed on the inner peripheral surface, ) And a flange portion (13) attached to the suspension device (vehicle body side portion) with a bolt.

  The rotation side raceway member (4) has a large diameter portion (15) having a first raceway groove (15a) and a small diameter portion (16) having an outer diameter smaller than the diameter of the first raceway groove (15a). The inner ring (14), and the inner ring (14), the inner ring (14), which has a small diameter part (16) and is fitted to the outer diameter, and the right side is in close contact with the left side of the large diameter part (15) of the inner axis (14) (17) Near the right end of the inner shaft (14), a flange portion (18) to which a plurality of bolts (19) for attaching a wheel is fixed is provided. A raceway groove (17a) is formed in the right part of the inner ring (17) so as to be parallel to the raceway groove (15a) of the inner shaft (14), and a shoulder part (17b ) Is formed. A sealing device (20) is provided between the right end portion of the fixed-side track member (3) and the inner shaft (14). A male screw is provided at the left end of the small diameter portion (16) of the inner shaft (14), and the inner ring (17) is connected to the inner shaft (14) by a nut (21) screwed to the male screw. It is fixed to. A cover (22) is covered with the left end portion of the fixed race member (3).

  The sensor device (2) is a multi-vibrator ultrasonic sensor (10) that detects a force (hereinafter referred to as a “rolling element load”) acting between the fixed-side track member (3) and the inner row of balls (5). And processing means (not shown) for processing the output of the multi-vibrator ultrasonic sensor (10).

  In this embodiment, only one multi-vibrator ultrasonic sensor (10) is provided on the top of the hub unit (1).

  In FIG. 2, the multi-vibrator ultrasonic sensor (10) has a total of 10 transducers (10b) with P.D. C. D. Are provided in the case (10b) so as to be arranged at an equal pitch in the circumferential direction of a concentric circle, and each of the vibrators (10b) from 1 to 10 outputs an ultrasonic wave and its reflected wave Can be received by the receiver, and the reflected echo can be obtained. The vibrators (10b) 1 to 10 are arranged at intervals of p / 10, where the pitch of the balls (5) is p.

 Outputs from the transducers (10b) 1 to 10 are obtained as echo ratios shown below.

Echo ratio = 100 × (H0−H1) / H0
H0: Echo intensity when the rolling element is separated from the ultrasonic sensor by a half pitch H1: Echo intensity when the rolling element is located directly below the ultrasonic sensor This echo ratio has the relationship shown in FIG. By using this, the rolling element load can be obtained from the echo ratio. If the load acting on the ball (5) is large, the contact area becomes large and the reflected wave becomes small. Therefore, when the rolling element load is large, a large echo ratio is output.

  The echo ratio has the relationship shown in FIG. 4 with the rotational speed, and the rotational speed can be obtained by measuring the number of pulses of the echo ratio within a certain time. Since the ultrasonic sensor (10) has a plurality of vibrators (10b), as shown in FIG. 5, each time the ball (5) revolves 1/10 (= p / 10) of one pitch. In the ultrasonic sensor (10), each of the transducers (10b) 1 to 10 sequentially detects one pulse at a time, and as a whole, the transducer is 10 times as large as a single ultrasonic sensor. The number of pulses (composite pulse signal) is obtained. Even if the rotational speed changes, the absolute value of the echo ratio is not affected by this.

  The processing means of the sensor device (2) includes a pulse number counting unit that counts the number of pulses of each vibrator (10b) from 1 to 10, a revolution speed calculation unit, and a rotation speed conversion unit. And a rotation speed calculation unit that obtains the rotation speed using the number of pulses obtained.

  The echo ratio output from each transducer (10b) 1 to 10 changes with time as the rotational speed of the wheel changes with time. Therefore, each time the echo ratio exceeds a predetermined threshold in the pulse number counting unit, the number of times (number of pulses) is counted, and then the rotation speed calculation unit can use this pulse number to obtain the rotation speed. .

  The rolling element revolution speed required to obtain the rotational speed is the circumferential length of the rolling element pitch or P.I. C. D. It is a function of the number of pulses and time. Since the arrangement of the vibrator (10b) is shifted by p / 10 corresponding to the pitch p of the balls (5) as described above, the revolution speed calculation unit has each of 1 to 10 arranged in the circumferential direction. All the pulse numbers from the oscillator (10b) are used to determine the revolution speed of the ball (5). In the rotation speed conversion unit, the revolution speed is converted into the rotation speed based on a well-known expression. In this way, the number of pulses obtained from all the vibrators (10b) from 1 to 10 is used to obtain a rotational speed that changes with time.

  The number of ultrasonic sensors (10) is not limited to one, and the number of transducers (10b) is not limited to ten. For example, multi-vibrator ultrasonic sensors (10) having six vibrators may be provided at two places in the circumferential direction. When two or more ultrasonic sensors (10) are arranged, when there are two ultrasonic sensors (10), the interval between the ultrasonic sensors (10) is 180 ° ± p / 2, and the ultrasonic sensors (10) In the case of four, the ultrasonic sensors (10) are connected to each other such that the reference position + 90 ° + p / 4, the reference position + 180 ° + 2p / 4, and the reference position + 270 ° + 3p / 4 with respect to the position of the first sensor. It is preferable to shift the interval. Moreover, in the above, although the hub unit with a sensor was demonstrated, the said sensor apparatus can be integrated and used for various rolling bearings other than a hub unit. Since the rolling element load has a correlation with the load acting on the rolling bearing, not only the rotation speed but also the load acting on the rolling bearing may be obtained.

FIG. 1 is a longitudinal sectional view showing a first embodiment of a rolling bearing device with a sensor according to the present invention. FIG. 2 is a cross-sectional view of a rolling bearing device with a sensor according to the present invention schematically drawn. FIG. 3 is a graph showing the relationship between the echo ratio obtained by the ultrasonic sensor and the rolling element load. FIG. 4 is a graph showing the relationship between the rotation speed and the echo ratio. FIG. 5 is a diagram showing the relationship between pulses obtained from each ultrasonic sensor and pulses obtained from all ultrasonic sensors.

Explanation of symbols

(1) Rolling bearing
(2) Sensor device
(3) Fixed side raceway member
(4) Rotating track member
(5) Ball (rolling element)
(11) Processing means
(10) Ultrasonic sensor
(10b) Vibrator

Claims (1)

In a rolling bearing device with a sensor provided with a rolling bearing having a stationary race member, a rotating race member and rolling elements, and a sensor device,
The sensor device includes an ultrasonic sensor that is provided in at least one location of the fixed-side track member and detects the rolling element load as an echo ratio, and a processing unit that obtains the rotational speed from the output of the ultrasonic sensor. The sensor has a plurality of vibrators arranged at a predetermined pitch inside, the plurality of vibrators are arranged at an equal pitch, and the pitch of the vibrator × the number of vibrators = one pitch of the rolling element A rolling bearing device with a sensor characterized by

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