JP2006208285A - Bearing with rotary sensor, and bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing with a rotary sensor having high precision easy to attach by facilitating manufacture, and to provide a bearing device. <P>SOLUTION: The bearing with the rotary sensor comprises an inner ring 10a and an outer ring 10b in which any one composes a rotary side race and the other composes a fixed side race, a plurality of rolling bodies 10c arranged between the rotary side race and the fixed side race, a sensor housing 1 attached to the fixed side race including a sensor element 3, and an encoder 5 having another integrated matter of the rotary side race and for a magnetic signal sensed with the sensor element. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bearing with a rotation sensor and a bearing device used in office equipment such as a copying machine and a printer.

  In a bearing with a rotation sensor, a magnetic or optical encoder is provided on a rotating raceway that rotates together with a rotation shaft of an applied apparatus, and a magnetic signal or an optical signal is detected on a non-rotating (fixed) raceway. The element is attached. In the optical encoder, a portion where light is reflected toward the sensor element and a portion where light is not reflected toward the sensor element are alternately arranged. In the case of a magnetic encoder, an N-pole and an S-pole arranged alternately in an annular shape are fitted into a cylindrical cored bar. A magnetic encoder including a mandrel causes a magnetic sensor element disposed on a fixed-side raceway ring to sense a periodic magnetic signal by rotation around a central axis.

In the case of a magnetic encoder, if there is a repetition of high and low temperatures in a large range from below freezing point to high temperature in the change in ambient temperature, the accuracy of the shape of the annular encoder is deteriorated and the magnetic accuracy of the magnetic field generator is caused by it. May deteriorate. In a magnetic encoder, a permanent magnet obtained by sintering a magnetic powder is usually used. In such a case, if the above temperature change continues for a long time, a crack is generated in the magnetic field generating part in which the particles are baked and hardened. Sometimes. For this reason, it has been proposed to use a heat-resistant rubber as a binder for the particulate permanent magnet (see Patent Document 1).
JP 2002-349556 A

  In the above magnetic encoder, it is necessary to vulcanize and bond an annular part containing a heat-resistant rubber binder to the core metal. For this reason, heat-resistant rubber and a core metal are required, and the number of manufacturing steps is increased to increase the manufacturing cost.

  An object of the present invention is to provide a highly accurate bearing and bearing device with a rotation sensor that is easy to manufacture.

  The bearing with a rotation sensor according to the present invention is arranged between an inner ring and an outer ring, one of which constitutes a rotation-side raceway and the other constitutes a fixed-side raceway, and between the rotation-side raceway and the fixed-side raceway. A plurality of rolling elements, a sensor housing including a sensor element and attached to a fixed-side raceway, and an encoder for a magnetic signal sensed by the sensor element, which is separate from the rotary-side raceway It is characterized by providing.

  According to said structure, since an encoder is an integral thing, manufacture is easy. Further, since it is configured as an integral object, the interval between adjacent magnetic poles is unlikely to change, and errors in sensing of the sensor element are unlikely to occur. Furthermore, the attachment to the rotating shaft can be simplified, and the error factors including the fluctuation of the magnetic pole interval due to a larger number of attachment steps can be reduced. The encoder can be easily attached to the rotating shaft by using a binding force, for example, if an integral encoder is formed of an elastic body. The encoder may be manufactured by, for example, arranging a powder sintered magnet in an elastic body and integrally forming the whole, and may be formed in an annular shape so that the rotating shaft is tightened from the outer periphery. A rubber magnet may be used. As long as the encoder is integrated and has elasticity, it is not necessary to include a member that can be specified as an elastic mounting member. Moreover, you may include the part which can be specified as an elastic attachment part. The elastic body corresponds to an elastic resin, rubber or the like.

  The encoder described above can be an integral rubber encoder. By using rubber, an encoder rich in elasticity unique to rubber can be configured, and can be easily attached to the rotating shaft by the binding force of the rubber.

  Further, the outer ring constitutes a fixed-side track ring, and the sensor housing can be attached with an annular metal body interposed in the outer ring. With this configuration, it is not necessary to make the finishing accuracy of the sensor housing particularly high, and it is not necessary to make a special shape that is not easy for die cutting or the like in manufacturing, for example, injection molding.

  Further, the outer ring constitutes a fixed-side track ring, a resin sensor housing is attached to the outer ring, and a locking mechanism that locks the outer ring and the sensor housing to each other is further provided. it can. With the above configuration, since a normal sealed bearing can be used for the bearing, the manufacture of the bearing device is further facilitated. In addition, the above-described locking mechanism can prevent axial displacement between the outer ring and the sensor housing. In addition, if the locking mechanism includes a locking groove along the axial direction, it is possible to prevent rotation along the circumferential direction.

  The bearing device of the present invention has a structure in which a rotating shaft made of steel is provided, and the encoder in any one of the bearings with the rotation sensor is mounted on the rotating shaft made of steel. According to this configuration, the magnetic flux generated between the adjacent S and N poles of the magnetic encoder passes through a path having a small magnetic resistance, and more magnetic flux can be generated using the same permanent magnet. it can. For this reason, a strong magnetic signal can be sent to the sensor element.

  Since the bearing with a rotation sensor and the bearing device of the present invention use an integral encoder, the bearing with the rotation sensor itself can be easily manufactured, and can be easily and accurately mounted on the rotating shaft. Furthermore, by mounting the encoder on a steel rotating shaft, the magnetic resistance between the magnetic poles of the encoder can be reduced to increase the magnetic signal of the encoder, and the encoder can be miniaturized. Further, in the case of a structure in which a resin sensor housing is attached to the outer ring, since a bearing with a seal can be used, the production of the bearing device is simplified.

  Next, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram showing a bearing with a rotation sensor according to Embodiment 1 of the present invention. FIG. 2 is a view showing a state in which the rotation sensor-equipped bearing of FIG. 1 is mounted on a rotation shaft. 3 is a cross-sectional view taken along line III-III in FIG.

  1 to 3, the bearing 10 includes an inner ring 10 a, an outer ring 10 b, and rolling elements (steel balls) 10 c. A sheet metal (steel plate) 18 is press-fitted and attached to the inner diameter of the outer ring 10b constituting the stationary side race ring by the elastic force of the steel plate. A sensor housing 1 in which the sensor element 3 is housed is attached and fixed to the sheet metal 18. The sensor housing 1 formed of resin or the like is separated from the rotating shaft 25 in FIG.

  As shown in FIG. 3, the rubber magnetic encoder 5 is configured such that N poles and S poles are alternately and periodically formed in an annular shape. And it attaches so that the rotating shaft 25 may be clamp | tightened from outer periphery with the binding force of rubber | gum, and it rotates with the rotating shaft 25. FIG. The magnet shown in FIG. 3 may be a rubber magnet, or the powder-sintered permanent magnet may be integrally formed with rubber.

  As shown in FIG. 3, when the N pole at one end of the permanent magnet is arranged on the outer peripheral side of the encoder 5, the S pole at the other end is arranged on the inner peripheral side. Therefore, when N poles and S poles are alternately arranged on the outer peripheral side, the S poles and N poles are alternately arranged so as to be in contact with the surface of the rotating shaft 25 on the inner peripheral side. The rotating shaft 25 is usually formed of steel that is a ferromagnetic material having a high relative magnetic permeability. For this reason, a magnetic path with a small magnetic resistance is formed between the adjacent S pole and N pole. The magnetic resistance is inversely proportional to the (ratio) permeability. Between the S pole and N pole adjacent to each other in the surface layer portion of the rotating shaft 25, the magnetic flux F does not spread in a space having a large magnetic resistance, but flows through a short path in the rotating shaft 25 that is a ferromagnetic material. . As a result, a larger amount of magnetic flux can be generated than in the case of mounting on the rotating shaft of the non-magnetic material, and the magnetic flux can be concentrated and directed to the sensor element 3.

  The sensor element 3 is disposed on the opposite side of the rotary shaft 25 with the magnetic encoder 5 interposed therebetween, but the magnetic flux on the sensor element 3 side has a small relative permeability (unit length) between the encoder 5 and the sensor element 3. It is necessary to pass through a gap (which has a large magnetic resistance per contact). However, it is preferable to shorten the gap length as much as possible to reduce the magnetic resistance in order to concentrate the sensor element 3 and send a magnetic signal. Further, it is preferable to place a ferromagnetic plate or the like on the back surface (the surface opposite to the magnetic encoder) of the sensor element 3 in order to attract the magnetic flux to the sensor element 3.

  The above-mentioned bearing with a rotation sensor is generally described as follows. In other words, one of the rotation-side race rings and the other of the fixed-side race rings constitute the inner ring 10a and the outer ring 10b, and a plurality of rolling rings arranged between the rotation-side raceway and the fixed-side raceway. The moving body 10c, the sensor housing 1 including the sensor element 3 and attached to the fixed-side raceway, and the encoder 5 for a magnetic signal sensed by the sensor element, which are separate from the rotation-side raceway, It is characterized by providing.

  According to said structure, since the encoder 5 is an integral thing, manufacture is easy. Further, it is possible to easily attach to the rotating shaft, and it is possible to reduce error factors including fluctuations in magnetic pole spacing caused by a larger number of mounting steps. As the encoder 5, for example, a rubber magnet or a sintered magnet disposed in an elastic body and integrally molded may be used. The encoder 5 is assumed to be annular so as to tighten the rotary shaft 25 from the outer periphery. The encoder 5 need only be an integral member and may have elasticity, and may not particularly include a member that can be specified as an attachment member to the rotating shaft 25. Alternatively, if it is an integral part, it may include a portion that is recognized as an attachment member to the rotating shaft 25. The magnetic encoder 5 can be attached to the rotary shaft 25 by press-fitting the magnetic encoder 5 into the rotary shaft 25. The elastic body corresponds to an elastic resin, rubber or the like.

  Further, the outer ring 10b may constitute a stationary side race ring, and the sensor housing 1 may be attached to the outer ring with a sheet metal 18 that is an annular metal body interposed therebetween. With this configuration, it is not necessary to make the finishing accuracy particularly high in the production of the sensor housing, and it is not necessary to make a special shape in production, for example, in injection molding.

(Embodiment 2)
FIG. 4 is a diagram showing a bearing with a rotation sensor according to Embodiment 2 of the present invention. In FIG. 4, the resin sensor housing 1 is attached so that the outer peripheral surface thereof is fitted into the outer ring 10 b constituting the fixed-side raceway ring. A locking groove 9 is provided on the outer peripheral surface of the outer ring, and the convex portion 19 of the sensor housing 1 is fitted and locked in the locking groove 9. For this reason, the bearing 10 and the sensor housing 1 are prevented from being separated from each other. The locking groove 9 is desirably provided intermittently, not continuously over the entire circumference of the outer ring 10b. By providing the groove 9 intermittently along the outer periphery of the outer ring 10b and providing the convex portion 19 so as to fit it, not only the relative displacement in the axial direction but also the relative rotation in the circumferential direction, that is, the rotational displacement is prevented. can do. A cable 21 for inputting a sensed signal to a processing circuit or the like is drawn out from the sensor element 3 through the sensor housing 1.

  A substrate 2 is fixed to the sensor housing 1, and a sensor element 3 is fixed on the substrate. The encoder 5 has a configuration in which a cylindrical portion 5a attached to the outer periphery of the rotary shaft 25 with a binding force and a disc portion 5b are integrally molded. The N pole and the S pole may be circumferentially arranged along the cylindrical portion 5a, or may be circumferentially arranged along the disc portion 5b. In FIG. 4, it arrange | positions to the cylindrical part 5b.

  In general, the relationship between the engaging groove 9 of the bearing outer ring 10b and the convex portion 19 of the sensor housing is that the outer ring 10b constitutes a stationary race ring, and the resin sensor housing 1 is attached to the outer ring 10b. In other words, it can be said that the holding mechanism 9 or 19 is further provided between the outer peripheral surface of the outer ring and the sensor housing. The locking mechanism may be configured to prevent not only relative displacement in the axial direction but also rotational displacement in the circumferential direction.

  In the case of a structure in which the sensor housing is made of resin and the resin sensor housing is molded on the outer ring of the bearing, a normal sealed bearing can be used for the bearing, which makes it easier to manufacture the bearing device.

  In addition, the bearing device of the present invention can have a configuration in which the rotating shaft 25 made of steel is provided, and the encoder 5 in any one of the above bearings with a rotation sensor is mounted on the rotating shaft 25 made of steel. . According to this configuration, the magnetic flux F generated between the adjacent S pole and N pole of the magnetic encoder passes through a path with a small magnetic resistance, and generates more magnetic flux using the same permanent magnet. Can do. For this reason, a strong magnetic signal can be sent to the sensor element 3.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  Since the bearing with a rotation sensor and the bearing device of the present invention use an integral encoder, the manufacture of the bearing with a rotation sensor is facilitated, and the mounting to the rotating shaft can be performed easily and accurately. It is expected that the application will be expanded. Further, by attaching the magnetic encoder to the steel rotating shaft, the magnetic resistance between the magnetic poles of the encoder can be reduced to increase the magnetic signal of the encoder, and the encoder can be miniaturized. Further, in the case of a structure in which a resin sensor housing is attached to the outer ring, since a bearing with a seal can be used, the production of the bearing device is simplified.

It is a figure which shows the bearing with a rotation sensor in Embodiment 1 of this invention. It is a figure which shows the state which mounted | wore the rotating shaft with the bearing with a rotation sensor of FIG. It is sectional drawing which follows the III-III line in FIG. It is a figure which shows the bearing with a rotation sensor in Embodiment 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Sensor housing, 2 Substrate, 3 Sensor element, 5 Encoder, 5a Encoder cylindrical part, 5b Encoder disc part, 9 Outer ring locking groove, 10 Bearing, 10a Inner ring, 10b Outer ring, 10c Rolling element (steel ball) , 18 Sheet metal, 19 Sensor housing convex part, 21 Cable, 25 Rotating shaft, F Magnetic flux.

Claims (5)

Any one of them constitutes a rotating side raceway, and the other constitutes a fixed side raceway, and an inner ring and an outer ring,
A plurality of rolling elements arranged between the rotating side raceway and the fixed side raceway;
A sensor housing including a sensor element and attached to the fixed-side raceway;
A bearing with a rotation sensor, which is an integral part separate from the rotation-side raceway and includes an encoder for a magnetic signal sensed by the sensor element.   The bearing with a rotation sensor according to claim 1, wherein the encoder is an integral rubber encoder.   The bearing with a rotation sensor according to claim 1 or 2, wherein the outer ring constitutes the fixed-side raceway ring, and the sensor housing is attached to the outer ring with an annular metal body interposed therebetween.   The outer ring constitutes the fixed-side raceway, the sensor housing made of resin is attached to the outer ring, and further provided with a locking mechanism that locks the outer ring and the sensor housing with each other. The bearing with a rotation sensor according to claim 1 or 2.   A bearing device having a steel rotating shaft, wherein the encoder in the bearing with a rotation sensor according to claim 1 is mounted on the steel rotating shaft.

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