JP2008019933A - Bearing device with sensor and bearing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive bearing device with sensors for measuring a load applied to a shaft and the rotating speed of the shaft at the same time. <P>SOLUTION: A bearing has rolling elements laid between an inner ring and an outer ring. One of the inner and outer rings is a rotating ring and the other is a stationary ring. The first sensor detects the revolving speed of the rolling elements or their cage and the second sensor detects the rotating speed of the rotating ring. The first and second sensors are arranged in a space between the rotating ring and the stationary ring. In accordance with a detection signal from the first sensor, a signal processing part calculates an axial load applied between the rotating ring and the stationary ring. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bearing with a sensor having a sensor for detecting an operating state of a rolling bearing device, a machine device, a spindle of a machine tool, and the like, and in particular, without providing a dedicated sensor for load detection, The present invention relates to a bearing device with a sensor and a bearing system capable of detecting a load.

  Conventionally, as a sensor-equipped bearing for detecting the rotational speed of a rotating member integrated with an inner ring or an outer ring, there is one disclosed in Patent Document 1, for example.

  FIG. 6 is a cross-sectional view in the axial direction (rotation axis XX direction of the bearing) showing the sensor-equipped bearing disclosed in Patent Document 1. The sensor-equipped bearing includes a stationary wheel 110, a rotating wheel 111, and a row of balls (plurality) 112 that are rotatably disposed between the stationary wheel 110 and the cage, and that are maintained at a fixed distance by a cage 131. , A measurement sensor 121 for rotational motion, and a phonic wheel (for example, a multipolar magnet) 120 fixed to the rotating wheel 111 by a holding member 122. The measurement sensor 121 is a sensor for measuring the mutual movement of the stationary wheel 110 and the rotating wheel 111, and is housed in the annular sensor carrier 123 and held by the holding device 124 (see Patent Document 1). .

As described above, the sensor-equipped bearing that measures the mutual movement of the two relatively rotating race rings is configured such that the detection sensor is attached to the outer ring that is a stationary ring via the holding member, and the detected member is attached to the inner ring that is the rotating ring. A multipolar magnet is provided. The detection sensor is generally housed in a sensor housing (annular sensor carrier 123 in the example of FIG. 6) and is held by a cover.
Japanese Patent Laid-Open No. 7-311212

  Incidentally, in the case of the conventional structure shown in FIG. 6, when an axial load (also referred to as a thrust load) applied in a direction parallel to the shaft is to be measured, it is necessary to provide a separate load sensor. Therefore, a new space for installing the load sensor is required. Moreover, since the load sensor is very expensive, the cost of the entire system is unavoidable. As described above, the conventional bearing requires a load sensor for measuring the axial load, and there is a problem that the installation space of the sensor device is increased and the cost is increased.

  The present invention has been made for the above-described circumstances, and an object of the present invention is to provide a sensor-equipped bearing that can be configured at low cost and can simultaneously measure the load applied to the shaft and the rotational speed of the shaft. To provide an apparatus.

  The present invention relates to a sensor-equipped bearing device and a bearing system capable of measuring an axial load, and the above object of the present invention is related to a sensor-equipped bearing device, one of which is a rotating wheel and the other is a stationary wheel. A sensor-equipped bearing device comprising a bearing portion having a rolling element interposed between the inner ring and the outer ring, and measuring the rotational speed of the detected object and simultaneously rotating the rotating wheel and the stationary ring. By providing a first sensor for detecting the revolution speed of the rolling element or its cage and a second sensor for detecting the rotational speed of the rotating wheel as sensors for measuring the axial load applied between them. Achieved.

  And a signal processing unit that calculates the axial load based on detection signals from the first and second sensors. The signal processing unit is based on detection signals from the first and second sensors. Calculating the axial load from the ratio between the revolution speed obtained and the rotational speed of the rotating wheel, and a sensor group in which two or more sensors including at least the first and second sensors are combined. The first and second sensors are one of two annular gaps formed between an inner peripheral surface of the outer ring, an outer peripheral surface of the inner ring, and upper and lower surfaces in the axial direction of the rolling element. The first and second sensors are formed between the inner peripheral surface of the outer ring, the outer peripheral surface of the inner ring, and the upper and lower surfaces in the axial direction of the rolling element. That of two annular voids Being disposed in the gap portion of the record, each of which is more effectively achieved by.

  Further, the first sensor detects any one of an encoder fixed to the cage, the cage formed by multipolar magnetization, and the rolling element made of a magnetic material for detecting the revolution speed. The second sensor is disposed in a notch portion formed at an end portion of the outer peripheral surface of the rotating wheel, and the detection part and the detected part of the second sensor are in the axial direction or It is more effectively achieved by being installed in the notch portion so as to face each other in the radial direction.

  Further, the bearing system is achieved by providing the sensor-equipped bearing device having the above-described configuration requirements in one of the two bearing portions that support the shaft of the rotating object. Alternatively, it is achieved by providing the sensor-equipped bearing device having the above-described constituent elements in both of the two bearing portions that support the shaft of the rotating object.

  According to the present invention, by measuring two rotational speeds (revolution speed and rotational speed), it is possible to analogize an axial load without using a load sensor. In addition, a sensor-equipped bearing device having a multi-sensing function capable of simultaneously measuring the axial load and the rotational speed or rotational speed of the shaft can be provided at a low cost. Furthermore, the axial load can be measured without providing a large installation space for the sensor outside the space between the rotating wheel and the stationary wheel.

(First embodiment)
FIG. 1 is a partial cross-sectional structure diagram showing a configuration example in a first embodiment of a sensor-equipped bearing device according to the present invention. The sensor-equipped bearing device of the present invention can be applied to various bearings such as bearings used in general vehicles such as railway vehicles, automobiles, and ships, and spindles of machine devices and machine tools. The case where it is applied will be described as an example. The configuration is the same even in cases other than vehicles.

  In FIG. 1, the bearing portion of the sensor-equipped bearing device includes an outer ring (stationary wheel) 11 fitted inside the vehicle body side housing, an inner ring 12 fitted around the axle and rotating together with the axle, an outer ring 11 and an inner ring 12. And a plurality of rolling elements (balls or rollers) 13 that are movably disposed between the inner ring raceway and the retainer 14 that holds each rolling body 13 between the inner ring raceway and the outer ring raceway. Yes.

  When the sensor-equipped bearing device is used, the cage 14 revolves around the inner ring 12 at the same speed as the revolution speed of each rolling element 13 revolving around the center of the shaft.

  The sensor-equipped bearing device according to the present invention includes, as sensors, a revolution speed detection sensor 21 (hereinafter referred to as a “revolution number detection sensor”) for detecting the revolution speed of the rolling element 13 or the cage 14, and a rotating wheel. (In this example, a rotation speed detection sensor 22 (hereinafter referred to as “rotation speed detection sensor”) for detecting the rotation speed of the inner ring 12, and the number of revolutions from the revolution speed detection sensor 21 as the shaft rotates. The detection signal and the rotation speed detection signal from the rotation speed detection sensor 22 are detected at the same time. When an axial load is applied between the inner ring 12 and the outer ring 11, the axial load can be measured based on the detection signal. It is said. That is, a pair of revolution speed detection sensor 21 and rotation speed detection sensor 22 functions as a sensor for measuring the rotational speed of the detected object and simultaneously measuring the axial load applied between the inner ring 12 and the outer ring 11. .

  The revolution number detection sensor 21 includes a detection element 21a as a detection unit that detects the revolution number of the rolling element 13 or the retainer 14, and an encoder 21b as a detected portion. In the present embodiment, the encoder 21b is fixed on the cage 14 side, and the revolution number of the rolling element 13 or the cage 14 (or both) is detected by the detection element 21a disposed opposite to the axial direction. It is configured.

  On the other hand, the rotation speed detection sensor 22 has a detection element 22a as a detection section that detects the rotation speed of the rotating wheel, and an encoder 22b as a detected section. The encoder 22b is fixed to the rotating wheel side. Specifically, the encoder 22b is fixed to a notch portion (the step portion 12a in FIG. 1) formed at the end of the outer peripheral surface of the inner ring 12 that is a rotating wheel, and faces the axial direction. The installed detection element 22a detects the rotational speed of the rotating wheel (in this example, the inner ring 12).

  In this example, magnetic detection sensors are used as the detection elements 21a and 22a of the detection sensors 21 and 22, and multipolar magnets are used as the encoders 21b and 22b. The magnetic sensitive sensors 21a and 22a and the multipolar magnets 21b and 22b are respectively placed in the space between the rotating wheel 12 and the stationary wheel 11 (in this example, the space between the bottom surface of the sensor housing and the rolling element). (Inside). The detection elements 21a and 22a are each mounted on an electronic circuit board 23 and configured to output signals to an external control system via a cable 24 drawn from the board 23.

  As shown in FIG. 1, the electronic circuit board 23 itself is fixed to the bottom surface portion of the annular sensor housing 25 so that the surface of the sensor mounting portion is exposed to the rolling element 13 side, and is further coupled to the sensor cover 26. Fixed. The sensor cover 26 is coupled and fixed to a stationary wheel (in this example, the outer ring 11). The electronic circuit board does not necessarily have to be exposed to the rolling element side of the surface of the sensor mounting part. When the sensor housing is molded, the electronic circuit board is integrally formed and molded into the sensor housing. You can choose.

  In the present embodiment, the arithmetic unit for calculating the axial load applied between the rotating wheel and the stationary wheel based on the detection signal from the revolution number detection sensor 21 is the signal processing unit of the detection sensors 21 and 22. It is mounted on the electronic circuit board 23. For example, the external control system generates the signal based on the signal indicating the axial load and the signal indicating the rotational speed of the detection target (the shaft, the rotation target connected to the shaft, or the like), or those signals. A signal indicating an abnormality diagnosis result of the bearing portion is transmitted. The axial load calculation process may be executed by an external control system, or may be executed by another arithmetic unit connected to the cable 24.

  Here, a method for calculating the axial load will be described.

  When an axial load is applied between the rotating wheel 12 and the stationary wheel 11, the contact angle of the rolling element 13 changes, and the revolution number of the rolling element 13 changes accordingly. Therefore, the speed ratio (= the revolution speed of the rolling element 13 / the rotation speed of the rotating wheel 12) can be obtained by measuring the revolution speed of the rolling element 13, and the axial load can be calculated from the change in the speed ratio. it can. Therefore, if information indicating the relationship between the speed ratio and the change in load is recorded in advance on a recording medium that can be read by an arithmetic unit that receives a signal, the axial load can be calculated based on the information.

In the present embodiment, the number of revolutions of the encoder 21b made of a multi-pole magnet integrated with the cage 14 is detected by a magnetic sensitive sensor 21 such as a Hall IC. However, the rolling element is made of a magnetic material. 13 may be configured to directly detect the revolution number of the rolling element 13. Moreover, although the number of revolutions and the number of rotations showed the detection system by a multipolar magnet and a magnetic sensitive sensor, if the number of revolutions and the number of rotations can be detected, a detection system will not ask | require. For example, any detection method may be used, such as using a mechanical encoder including a gear or the like instead of a magnetic encoder, or using an optical encoder. Furthermore, in this example, the revolution number and the rotation number detection method are the same, but different detection methods may be used. Further, the cage 14 itself may be made of magnetic plastic and may be magnetized with multiple poles.
(Modification of the first embodiment)
FIG. 2 is a partial cross-sectional structure diagram showing a modification of the first embodiment. The same components as those in the first embodiment shown in FIG.

The sensor-equipped bearing device shown in FIG. 1 illustrates the case where the rotational speed detection direction is the axial direction, but the sensor-equipped bearing device shown in FIG. 2 is an example where the rotational speed detection direction is the radial direction. It is. In this example, as shown in FIG. 2, the detection element 22a ′ of the rotation speed detection sensor 22 ′ and the encoder 22b ′ are opposed in the radial direction to measure the rotation speed of the rotating wheel. Comparing the configurations of FIG. 1 and FIG. 2, there is no difference in function as a sensor-equipped bearing device, and either of them may be applied in consideration of application characteristics and the like.
(Second Embodiment)
FIG. 3 is a partial cross-sectional structure diagram showing a configuration example in the second embodiment of the sensor-equipped bearing device according to the present invention. The same components as those in the first embodiment shown in FIG. The description is omitted.

  In the second embodiment, like the first embodiment, one end (specifically, between the inner peripheral surface of the outer ring 11, the outer peripheral surface of the inner ring 12, and the upper and lower surfaces of the rolling element 13 in the axial direction). In the case where it is difficult to fit both the rotation speed detection sensor 22 and the revolution speed detection sensor 21 in one of the two annular gap portions formed in the above, the detection element 22a "of the rotation speed detection sensor 22" Also, the encoder 22b ″ and the detection element 21a and encoder 21b of the revolution detection sensor 21 may be provided at both ends (upper and lower gaps in FIG. 3) as shown in FIG. Even if it is a simple structure, there is no trouble in the rotation speed detection and the load detection, and the function does not change as compared with the first embodiment.

  In this example, the rotational speed and revolution number are detected in the axial direction, but a combination detection method in which one of them is the radial direction and the other is the axial direction may be used.

Below, the example of the system to which the bearing apparatus with a sensor which concerns on this invention is applied is shown.
(First application example)
FIG. 4 is a schematic diagram showing a first example of a system in which the sensor-equipped bearing device shown in the first and second embodiments is applied to a speed reduction mechanism.

  In this example, the sensor-equipped bearing device 10 of the present invention is applied to one side of the rotating object 1 that supports the rotating shaft 2. The bearing system shown in FIG. 4 includes a driven pulley 3a attached to the end of the rotating shaft 2 of the rotating object 1 and a driving pulley 3b fixed to the rotating shaft of the motor 4 as a power source via a belt 3c. A speed reduction mechanism 3 that is connected is provided, and the rotating object 1 is rotationally driven around the rotation shaft 2 via the speed reduction mechanism 3.

  The sensor-equipped bearing device 10 can simultaneously measure the rotational speed of the rotary shaft 2 and the axial load applied to the rotary shaft 2.

  When an axial load is input from the rotating object 1, it can be measured regardless of the load in either the left or right direction. When two bearings are used as in this example, the sensor-equipped bearing device 10 is applied to the bearing on the left side (the rotating object 1 side) in FIG. 4, but depending on the characteristics of the application, It can also be applied to.

In this example, the axis is horizontal (for example, parallel to the ground), but the load can be measured even when the axis is vertical (for example, vertical to the ground).
(Second application example)
FIG. 5 shows an example of a system in which two sets of bearing devices with a sensor are combined in the first application example, and the same components are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 5, when two sets of bearing device 10 with a sensor are applied, a difference between both speed ratios (ratio between revolution speed and rotation speed) is obtained, and the calculated value of the axial load is corrected, The influence of preload etc. can be suppressed. That is, the axial load measurement accuracy can be further improved. Further, by obtaining the sum of the revolution speed ratios, it is possible to obtain an effect of further improving the measurement accuracy of the axial load. Further, the sensor-equipped bearing device 10 may be combined in the same direction as well as being combined so as to face each other as in the example of FIG. In this example, an axial load calculation process or the like is executed by an arithmetic unit connected to each cable 24 or an external control system.

  As described above, by using the sensor-equipped bearing device capable of measuring the load and the rotational speed, it is not necessary to separately prepare a rotation sensor and a load sensor, so that space can be improved. In addition, since the load sensor is expensive, the cost can be reduced by using the sensor-equipped bearing device of the present invention.

  In the above-described embodiment, the deep groove ball bearing is illustrated and described, but it can also be applied to a bearing such as an angular ball bearing. Further, it can be applied not only to a single row but also to a double row bearing. Moreover, although what combined the sensor for rotational speed detection and the sensor for revolution speed detection was described, according to the structure of the combination of two or more sensors including at least these sensors for speed detection, for example according to the characteristic of an application A configuration in which a temperature sensor, a vibration sensor, or the like is combined may be used. Moreover, although the case where the rotating wheel is an inner ring has been described as an example, the sensor-equipped bearing device of the present invention can be applied not only to the inner ring rotating bearing but also to the outer ring rotating bearing. Further, in the above-described embodiment, the case where the rotation speed detection sensor and the revolution speed detection sensor are used as the sensor for detecting the rotation speed and the revolution speed has been described as an example. Any sensor that can measure the rotational speed such as angle, speed, acceleration, etc., and any sensor is included in the present invention.

It is a partial cross section figure showing the example of composition in a 1st embodiment of the bearing device with a sensor concerning the present invention. It is a partial cross section figure showing the modification of a 1st embodiment. It is a partial cross section figure showing the example of composition in a 2nd embodiment of the bearing device with a sensor concerning the present invention. It is a schematic diagram which shows the 1st application example of the system which applied the bearing apparatus with a sensor which concerns on this invention to the deceleration mechanism. It is a schematic diagram which shows the 2nd application example of the system which applied the bearing apparatus with a sensor which concerns on this invention to the deceleration mechanism. It is an axial sectional view showing an example of a conventional bearing device with a sensor.

Explanation of symbols

1 Rotating object 2 Axis 3 Deceleration mechanism 4 Power source (motor)
10 Bearing device with sensor 11 Outer ring (stationary ring)
12 Inner ring (rotating wheel)
12a Step (notch)
13 Rolling body 14 Cage 21 Revolution speed detection sensor 21a Detection element 21b Encoder 22, 22 ', 22 "Revolution speed detection sensors 22a, 22a', 22a", Detection elements 22b, 22b ', 22b ", Encoder 23, 23a, 23b Electronic circuit board 24 Cable 25 Sensor housing 26 Sensor cover

Claims (11)

A bearing device with a sensor having an inner ring and an outer ring, one of which is a rotating wheel and the other is a stationary ring, and a bearing portion having a rolling element interposed therebetween, and measuring the rotational speed of the detected object At the same time, as a sensor for measuring an axial load applied between the rotating wheel and the stationary wheel, a first sensor for detecting the revolution speed of the rolling element or its cage, and the rotational speed of the rotating wheel A sensor-equipped bearing device comprising a second sensor for detection. The sensor-equipped bearing device according to claim 1, further comprising a signal processing unit that calculates the axial load based on detection signals from the first and second sensors. The signal processing unit calculates the axial load from a ratio between the revolution speed obtained based on detection signals from the first and second sensors and a rotation speed of the rotating wheel. 2. A sensor-equipped bearing device according to 2. The sensor-equipped bearing device according to any one of claims 1 to 3, further comprising a sensor group in which two or more sensors including at least the first and second sensors are combined. The first and second sensors are one of two annular gaps formed between an inner peripheral surface of the outer ring, an outer peripheral surface of the inner ring, and upper and lower surfaces in the axial direction of the rolling element. The sensor-equipped bearing device according to claim 1, wherein the sensor-equipped bearing device is disposed in a gap portion of the sensor. Each of the first and second sensors includes two annular gaps formed between an inner circumferential surface of the outer ring, an outer circumferential surface of the inner ring, and upper and lower surfaces in the axial direction of the rolling element. The sensor-equipped bearing device according to claim 1, wherein the sensor-equipped bearing device is disposed in a portion. In the first sensor, any of an encoder fixed to the cage, the cage formed by multipolar magnetization, and the rolling element made of a magnetic material is used as the detected portion for detecting the revolution speed. The sensor-equipped bearing device according to claim 1, wherein the bearing device is equipped with a sensor. The sensor-equipped bearing device according to any one of claims 1 to 7, wherein the second sensor is arranged in a notch portion formed at an outer peripheral surface end portion of the rotating wheel. The sensor-equipped bearing device according to claim 8, wherein the detection unit and the detection target portion of the second sensor are disposed in the cutout portion so as to face each other in the axial direction or the radial direction. A bearing system comprising the sensor-equipped bearing device according to any one of claims 1 to 9 on one of two bearing portions that support a shaft of a rotating object. A bearing system comprising the sensor-equipped bearing device according to any one of claims 1 to 9 in both of two bearing portions that support a shaft of a rotating object.

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