JP2006233985A - Bearing with rotation detection unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing with a rotation detection unit capable of miniaturizing in size and shortening an axial length. <P>SOLUTION: The bearing with a rotation detection unit has a magnetism generating means 2 for having directivity around a rotation center O at an inner ring 21 side of the bearing 20. A rotary sensor 3 which outputs rotation or angle information by sensing the magnetism of the magnetism generating means 2 is mounted at an outer ring 22 side while it is positioned on an axis of the bearing. The magnetism generating means 2 is fixed on a fixing member, for example, a rotary shaft 10 fixed on a bore side of an inner ring 21 of the bearing 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bearing with a rotation detection device used for rotation detection in various devices, for example, rotation detection for rotation control of a small motor, rotation detection for position detection of office equipment, detection of a joint angle of a robot, etc. About.

  In order to detect the rotation or angle of a robot joint or the like, a bearing with a rotation detector integrated with a bearing for supporting the shaft of the joint is installed. Such a bearing with a rotation detection device is desired to be small, and in particular when mounted on a joint such as a finger of a robot, it is desired to be smaller. In order to respond to such a request, the present applicant has previously proposed a bearing with a rotation detection device as shown in FIG. 22 (for example, Patent Document 1).

In the bearing with a rotation detection device of the figure, a magnetic generating means 32 having a direction around the center of rotation is arranged on the inner ring 51 side which is a rotating ring, and the magnetic generating means 32 is arranged on the outer ring 52 side which is a fixed ring. A magnetic line sensor 33 for detecting magnetism is arranged opposite to the magnetism generating means 32. The magnetism generating means 32 comprises a permanent magnet 32A and a magnetic yoke 32B, and is attached to the inner ring 51 via a magnetizing means attaching member 45 that is press-fitted to the outer diameter surface of the inner ring 51. Since the rotating shaft 40 and the inner ring 51 rotate integrally, the magnetism generating means 32 also rotates together with the rotating shaft 40 together with the magnetism generating means mounting member 45. The magnetic line sensor 33 is attached to the outer ring 52 via a sensor attachment member 57 that is press-fitted to the inner diameter surface of the outer ring 52.
JP 2004-37133 A

  However, in the bearing with the rotation detection device having the above configuration, the assembly structure to the bearing is not optimized, and the axial dimension is long. That is, since the magnetism generating means 32 is attached to the inner ring 51 by interposing the magnetism generating means mounting member 45 that is press-fitted into the outer diameter surface of the inner ring 51, the overall axial dimension is lengthened and the size is reduced. Was not enough.

  An object of the present invention is to provide a bearing with a rotation detecting device that can be miniaturized and that can shorten the axial dimension.

The bearing with a rotation detection device of the present invention has a magnetism generating means having directionality around the center of rotation on the inner ring side of the bearing, and outputs rotation or angle information by sensing magnetism of the magnetism generating means on the outer ring side. The rotation sensor is a bearing equipped with a rotation detecting device mounted on the bearing shaft, wherein the magnetism generating means is fixed to a fixing member fixed to the inner diameter side of the inner ring of the bearing.
According to this configuration, since the magnetism generating means is fixed to the fixing member fixed to the inner diameter side of the inner ring of the bearing, unlike the case where the fixing member fixed to the outer diameter side is used, the fixing member is more than the end surface of the inner ring. Therefore, it is not necessary to make the protrusions protrude greatly, and the axial length can be shortened.

  The fixing member may be a shaft. In this configuration, since the fixing member for fixing the magnetism generating means is also used as the shaft, there is no need to provide a fixing member that was conventionally required separately, the number of parts can be reduced, and the axial length reduction effect Can be further increased.

  The fixing member may be a member different from the shaft, and may be fixed to the inner ring inner surface by press-fitting or bonding. Since the magnetism generating means is fixed to a fixing member separate from the shaft, the length in the axial direction can be shortened compared to the conventional example while having the feature of the conventional example that the shaft can be separated from the bearing with the rotation detecting device. .

In this invention, the fixing member may be positioned by contacting the end surface of the inner ring or a stepped surface facing the axial direction processed into the inner ring. When it is assumed that it contacts the end surface of the inner ring, the fixing member may have a flange on the outer periphery of the inner ring fitting portion, and may contact the end surface of the inner ring with the flange.
In the case of this configuration, the fixing member can be easily positioned on the inner diameter side of the inner ring using the end face of the inner ring or the stepped surface as a reference plane. As a result, the fixing member can be attached to the inner ring so that the fixing surface of the magnetism generating means in the fixing member is perpendicular to the axis of the bearing, that is, the magnetism generating means is parallel to the rotation sensor. Therefore, the parallelism and clearance between the magnetism generating means and the rotation sensor can be maintained at a predetermined accuracy. As a result, it is possible to suppress the intensity of the magnetic field pattern on the surface of the rotation sensor from fluctuating due to rotation of the magnetism generating means. Further, since the clearance can be made smaller than in the conventional case, the magnetic field sensed by the rotation sensor is increased, and the S / N ratio is improved accordingly. With these two effects, the rotation detection accuracy of the rotation detection device can be improved.

In this invention, the magnetism generating means may be composed of two permanent magnets magnetized in the axial direction.
In this configuration, if the fixing member is made of a magnetic material, the fixing member becomes a magnetic path of the magnetism generating means. Therefore, the magnetic flux generated from the magnetism generating means and passing through the surface of the opposing rotation sensor is increased, thereby detecting the rotation. Sensitivity can be improved. In addition, the magnetism generating means is not composed of the combination of the permanent magnet and the magnetic yoke as in the conventional example, but the magnetism generating means is composed of only the permanent magnet, so that it is thinner than the conventional example. From this point, the axial length can be shortened.

  In the present invention, the magnetism generating means may be composed of one permanent magnet having both N pole and S pole on one side. In the case of this configuration, the magnetism generating means can be easily configured with only one permanent magnet. Further, since the magnetic flux of the permanent magnet does not pass to the fixed member side, the magnetic characteristics of the fixed member hardly affect the magnetic flux passing through the rotation sensor. Therefore, any fixing member of a magnetic body and a non-magnetic body can be used without affecting the rotation detection accuracy.

  In this invention, you may provide a recessed part in the said fixing member, and may fix a permanent magnet in this recessed part. Since the permanent magnet has an attractive force or a repulsive force between another permanent magnet or a magnetic body, when the fixing member is made of a magnetic body, it is not easy to assemble the permanent magnet to the fixing member. However, by inserting the permanent magnet into the recess formed in the fixing member, the permanent magnet can be fixed to the fixing member easily with high accuracy with less axial deviation.

  In this invention, you may surround the said permanent magnet with flexible materials, such as resin softer than the said magnetism generation means and the said fixing member, and may fix the said flexible material in the said recessed part with the said permanent magnet. When the permanent magnet is made of, for example, sintered material, the mechanical strength is fragile and is not suitable for press-fitting. However, by using the above assembly structure, the permanent magnet can be press-fitted into the recess.

  In the present invention, the fixing member may be a nonmagnetic material, and a magnetic yoke may be sandwiched between the magnetism generating means and the fixing member. When the magnetism generating means is a permanent magnet magnetized in the axial direction, when the fixing member is made of a non-magnetic material, the magnetic efficiency of the magnetism generating means is deteriorated if the permanent magnet is directly fixed to the fixing member. However, by adopting the above assembly structure in which the magnetic yoke is interposed, the magnetic flux passing through the surface of the rotation sensor can be increased by several percent compared to the case without the magnetic yoke. As a result, the S / N ratio of the magnetic signal sensed by the rotation sensor is improved, and the rotation detection accuracy can be further improved.

  In the present invention, the rotation sensor is formed by integrating a plurality of magnetic sensor elements and means for converting the output of the magnetic sensor elements into a rotation signal or an angle signal, for example, integrated on a semiconductor chip. There may be. As described above, if the magnetic sensor element and the angle signal conversion means are integrated and integrated on the semiconductor chip, wiring between the magnetic sensor element and the angle signal conversion means becomes unnecessary, the rotation sensor can be made compact, and the wire breakage, etc. As a result, the rotation detecting device can be easily assembled.

In the present invention, the rotation sensor includes a four-side magnetic line sensor in which magnetic sensor elements are arranged along four sides of a virtual rectangle, and the magnetic line sensor is provided inside the rectangular arrangement of the magnetic line sensor. You may arrange | position the calculation means which converts the sensor output of a sensor into rotation information or angle information.
In the case of this configuration, the chip size of the semiconductor chip constituting the rotation sensor can be further reduced.

  In this configuration, the plurality of magnetic sensors inside the rotation sensor detect a sine signal and a cosine signal of a magnetic field that rotates as the magnetism generating means rotates, and the conversion circuit detects the magnetic sensor. It may have a calculation means for converting the processed signal into a rotation signal or an angle signal.

  The bearing with a rotation detection device of the present invention has a magnetism generating means having directionality around the center of rotation on the inner ring side of the bearing, and outputs rotation or angle information by sensing magnetism of the magnetism generating means on the outer ring side. The rotation sensor is a bearing with a rotation detection device mounted on the bearing shaft center, and the magnetism generating means is fixed to a fixing member fixed to the inner diameter side of the inner ring of the bearing, so that the size can be reduced. In particular, the axial length can be shortened.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of a bearing with a rotation detection device of this embodiment. This bearing with a rotation detection device is one in which the rotation detection device 1 is incorporated in a rolling bearing 20. The rolling bearing 20 includes a rolling element 24 held by a cage 23 between rolling surfaces of an inner ring 21 and an outer ring 22. The rolling element 24 is formed of a ball, and the rolling bearing 20 is a single row deep groove ball bearing. The rotary shaft 10 is fitted in the inner ring 21 in a press-fit state, and the outer ring 22 is installed in a housing (not shown) of a bearing-using device.

The rotation detection device 1 includes magnetism generating means 2 arranged on the inner ring 21 side of the rolling bearing 20 and a rotation sensor 3 arranged on the outer ring 22 side. Here, the inner ring 21 side is an inner ring 21 or a member that rotates together with the inner ring 21, and the outer ring 22 side is an outer ring 22 or a member fixed to the outer ring 22.
The magnetism generating means 2 is made of a permanent magnet, and as shown in FIG. 2, the generated magnetism has directionality around the rotation center O of the rolling bearing 20. The magnetism generating means 2 made of a permanent magnet is fixed to the center of one end surface of the rotary shaft 10 as a fixed member so that the rotation center O of the rolling bearing 20 coincides with the center of the permanent magnet 2. In the magnetism generating means 2, the N magnetic pole and the S magnetic pole rotate around the rotation center O by the rotation of the rotating shaft 10.

  The rotation sensor 3 is a sensor that senses the magnetism of the magnetism generating means 2 and outputs rotation or angle information. The rotation sensor 3 is attached to the outer ring 22 side via a sensor attachment member 27 so as to face the magnetism generating means 2 in the axial direction of the rotation center O of the rolling bearing 20. Specifically, the sensor attachment member 27 is attached to the outer ring 22, and the rotation sensor 3 is fixed to the sensor attachment member 27. The sensor mounting member 27 has an outer peripheral tip cylindrical portion 27a fitted to the inner diameter surface of the outer ring 22, and a flange portion 27b formed in the vicinity of the distal cylindrical portion 27a is engaged with the width surface of the outer ring 22 in the axial direction. Positioning has been made. An output cable 29 for taking out the output of the rotation sensor 3 is also attached to the sensor attachment member 27.

As shown in a plan view in FIG. 3, the rotation sensor 3 includes a plurality of magnetic sensor elements 5a and a conversion circuit 6 that is a calculation means for converting the output of the magnetic sensor element 5a into a rotation signal or an angle signal. It is integrated on the semiconductor chip 4. On the semiconductor chip 4, the magnetic sensor element 5 a is arranged along each side of the four sides on the virtual rectangle to form the four-side magnetic line sensors 5 </ b> A to 5 </ b> D. In this case, the rectangular center O ′ coincides with the rotational center O of the rolling bearing 20. The four side magnetic line sensors 5A to 5D are configured such that the sensor elements 5a are arranged in a line in the example of the figure, but the sensor elements 5a may be arranged in parallel in a plurality of lines.
The conversion circuit 6 is arranged inside the rectangular arrangement of the magnetic line sensors 5A to 5D. The semiconductor chip 4 is fixed to the sensor mounting member 27 so that its element forming surface faces the magnetism generating means (permanent magnet) 2.

  As described above, when the magnetic sensor element 5a and the conversion circuit 6 are integrated and integrated on the semiconductor chip 4, wiring between the magnetic sensor element 5a and the conversion circuit 6 becomes unnecessary, and the rotation sensor 3 can be made compact. In addition, reliability against disconnection and the like is improved, and the assembly operation of the rotation detection device 1 is facilitated. In particular, if the conversion circuit 6 is arranged inside the magnetic line sensors 5A to 5D arranged in a rectangular shape as described above, the chip size can be further reduced.

4 and 5 are explanatory diagrams of angle calculation processing by the conversion circuit 6. 5A to 5D show output waveform diagrams of the magnetic line sensors 5A to 5D when the rotary shaft 10 is rotating, and the horizontal axes thereof are magnetic sensor elements in the magnetic line sensors 5A to 5D. 5a, the vertical axis indicates the intensity of the detected magnetic field.
Now, assume that there are zero-cross positions at the positions X1 and X2 shown in FIG. 4 that are boundaries between the N magnetic pole and the S magnetic pole of the magnetic field detected by the magnetic line sensors 5A to 5D. In this state, the outputs of the magnetic line sensors 5A to 5D have signal waveforms shown in FIGS. Therefore, the zero cross positions X1 and X2 can be calculated by linear approximation from the outputs of the magnetic line sensors 5A and 5C.
The angle calculation can be performed by the following equation (1).
θ = tan ⁻¹ (2 L / b) (1)
Here, θ is a value indicating the rotation angle θ of the magnet 2 as an absolute angle (absolute value). 2L is the length of one side of a quadrangle composed of the magnetic line sensors 5A to 5D arranged in a rectangle. b is the lateral length between the zero-cross positions X1 and X2.
When the zero-cross positions X1 and X2 are in the magnetic line sensors 5B and 5D, the rotation angle θ is calculated in the same manner as described above based on the zero-cross position data obtained from the outputs. The rotation angle θ calculated by the conversion circuit 6 is output from the output cable 29.

  According to the bearing with the rotation detection device having the above-described configuration, the magnetism generating means (permanent magnet) 2 of the rotation detection device 1 is fixed to a fixing member (here, the rotation shaft 10) fixed to the inner diameter side of the inner ring 21 of the rolling bearing 20. Therefore, unlike the conventional example of FIG. 22, a fixing member protruding in the axial direction from the inner ring end face is unnecessary, and the axial length can be shortened. Further, since the magnetism generating means is not composed of a combination of a permanent magnet and a magnetic yoke as in the conventional example, but the magnetism generating means 2 is composed of only the permanent magnet, it is thinner than in the case of the conventional example. From this point, the axial length can be shortened. In particular, in this embodiment, the fixing member for fixing the magnetism generating means 2 is also used by the rotary shaft 10, so that there is no need to provide a separate fixing member, the number of parts can be reduced, and the axial length shortening effect can be reduced. Can be further increased.

In the above embodiment, the rotation sensor 3 is configured such that the magnetism of the magnetism generating means 2 is sensed by the magnetic line sensors 5A to 5D in which a plurality of magnetic sensor elements 5a are arranged in a rectangle on the semiconductor chip 4. 6, at least two magnetic sensor elements 5 a and 5 b are arranged around a center O ′ on the semiconductor chip 4 (corresponding to the rotation center O of the rolling bearing 20) with a 90 ° rotation angle. The rotation sensor 3A may be configured.
In the example shown in the figure, the conversion circuit 6, which is a calculation means for converting the outputs of the magnetic sensor elements 5a and 5b into rotation signals or angle signals, is integrated on the semiconductor chip 4 together with the magnetic sensor elements 5a and 5b. This is the same as in FIG.

  When the rotation sensor 3A is configured as in the example of FIG. 6, the outputs of the two magnetic sensor elements 5a and 5b change in accordance with the rotation angle θ (FIG. 6) of the magnetism generating means 2, as shown in FIG. The output a of one magnetic sensor element 5a is a sine signal, and the output b of the other magnetic sensor element 5b is a cosine signal. Thus, the rotation angle θ can be calculated by an arctangent function (arc tangent) of a / b and the sign of a and b. This calculation is performed by the conversion circuit 6. When the output waveform of FIG. 7 is distorted with respect to ideal sine waves and cosine waves, a correction table is provided in the conversion circuit 6 to correct the distortion and prevent deterioration in accuracy of the detected rotation angle θ. You may do it.

In the above embodiment, the configuration of the magnetism generating means 2 has not been described in detail. As a specific configuration thereof, as shown in a side view and a front view in FIGS. The magnetized two quadrangular permanent magnets 2A and 2B may be arranged side by side in the radial direction with the axis O of the rotating shaft 10 as the center. The shapes of the permanent magnets 2A and 2B may be other shapes such as a semicircle.
In the case of this configuration, if the rotating shaft 10 is a magnetic body, a part of the rotating shaft 10 becomes a magnetic path of the magnetism generating means 2, so that the semiconductor chip 4 generated by the magnetism generating means 2 and facing (rotation sensor 3). The magnetic flux passing through the surface of the surface increases, and the rotation detection sensitivity can be improved.

As another specific configuration of the magnetism generating means 2, as shown in a side view and a front view in FIGS. 9A and 9B, there is one circular permanent magnet 2C having an N magnetic pole on one side and A magnet with an S magnetic pole may be arranged on the end surface of the rotating shaft 10 so that the center thereof coincides with the axis O of the rotating shaft 10. The shape of the permanent magnet 2C may be another shape such as a quadrangle.
In the case of this configuration, the magnetism generating means 2 can be easily configured with only one permanent magnet 2C. Further, since the magnetic flux of the permanent magnet 2C does not pass to the rotating shaft 10, the magnetic characteristics of the rotating shaft 10 hardly affect the magnetic flux passing through the semiconductor chip 4 (rotation sensor 3). Therefore, any rotating shaft 10 of a magnetic material and a non-magnetic material can be used without affecting the rotation detection accuracy.

  Moreover, although the case where the permanent magnet 2 which is a magnetic generation means is fixed to the end surface of the rotating shaft 10 as it is is shown in the said embodiment, not only this but as shown in FIG. A recess 10a may be formed on the end surface, and the permanent magnet 2 may be inserted into the recess 10a and fixed as shown in FIG. Since the permanent magnet 2 has an attractive force and a repulsive force between other permanent magnets and a magnetic body, when the rotating shaft 10 is made of a magnetic material, the assembly of the permanent magnet 2 to the rotating shaft 10 is not easy. However, by inserting the permanent magnet 2 into the recessed portion 10a formed on the rotating shaft 10 as described above, the permanent magnet 2 can be fixed to the rotating shaft 10 easily with high accuracy with less axial deviation. . Further, when the magnetism generating means 2 is constituted by two permanent magnets 2A and 2B as shown in FIG. 8, by adopting the assembly structure described above, the permanent magnets 2A and 2B can be connected to each other, and the rotation shaft of these and the magnetic body. Even if an attractive force or a repulsive force is applied to the rotating shaft 10, the permanent magnets 2A and 2B can be fixed to the rotating shaft 10 easily and accurately with less axial displacement.

FIG. 11 shows another example of a configuration in which the permanent magnets 2A and 2B, which are magnetism generating means, are inserted and assembled into the recess 10a formed on the end surface of the rotating shaft 10. In this case, as shown in FIG. 11B, the permanent magnets 2A and 2B are surrounded by the permanent magnets 2A and 2B, which are relatively flexible than the permanent magnets 2A and 2B and the rotating shaft 10, for example, by the resin member 11. The resin member 11 is integrated. By assembling the integrated component 12 into a recess 10 a formed on the end surface of the rotating shaft 10, the permanent magnets 2 </ b> A and 2 </ b> B are assembled to the rotating shaft 10.
When the permanent magnets 2A and 2B are made of, for example, sintered, the mechanical strength is fragile and is not suitable for press-fitting. However, by adopting the above assembly structure, the permanent magnets 2A and 2B can be press-fitted into the recess 10a. . This assembly structure may be employed for the assembly of a single permanent magnet 2C as shown in FIG. 9, and in this case, the permanent magnet 2C can be easily press-fitted into the recess 10a.

FIG. 12 shows a configuration example in which the magnetism generating means 2 composed of the two permanent magnets 2A and 2B shown in FIG. 8 is assembled to the end face of the rotating shaft 10 made of a non-magnetic material. In this assembly example, the permanent magnets 2 </ b> A and 2 </ b> B are assembled to the end surface of the rotating shaft 10 via the magnetic yoke 13. Specifically, a concave portion 13a is formed on one surface of the magnetic yoke 13, the permanent magnets 2A and 2B are inserted and fixed in the concave portion 13a, and the magnetic body is formed in the concave portion 10a formed on the end surface of the rotary shaft 10. The yoke 13 is inserted and fixed. As an assembling order, the permanent magnets 2A and 2B may be inserted and fixed in the recess 13a of the magnetic yoke 13 after the magnetic yoke 13 is inserted and fixed in the recess 10a of the rotary shaft 10 first. .
Since the two permanent magnets 2A and 2B constituting the magnetism generating means 2 are magnetized in the axial direction, when the rotary shaft 10 is made of a nonmagnetic material, the permanent magnets 2A and 2B are magnetically fixed to the rotary shaft 10 directly. The magnetic efficiency of the generating means 2 is deteriorated. However, by adopting the above assembly structure in which the magnetic yoke 13 is interposed, the magnetic flux passing through the surface of the semiconductor chip 4 (rotation sensor 3) can be increased by several percent compared to the case without the magnetic yoke. . As a result, the S / N ratio of the magnetic signal sensed by the rotation sensor 3 is improved, and the rotation detection accuracy can be further improved.

  FIG. 13 shows another configuration example in which the magnetism generating means 2 including the two permanent magnets 2A and 2B shown in FIG. 8 is assembled to the end face of the nonmagnetic rotating shaft 10. In this assembly example, two permanent magnets 2A and 2B are overlapped and fixed on one surface of the magnetic yoke 13, and the periphery thereof is surrounded by the resin member 11 to form an integrated component 14, which is formed on the end surface of the rotary shaft 10. The integrated part 14 is inserted and fixed in the recess 10a. Also in this case, the magnetic yoke 13 is sandwiched between the nonmagnetic rotating shaft 10 and the permanent magnets 2A and 2B, so that the magnetic efficiency of the magnetism generating means 2 is improved.

  FIG. 14 shows another embodiment of the present invention. The bearing with a rotation detection device of this embodiment is the same as the embodiment of FIG. 1 except that the insertion length of the rotary shaft 10 with the magnetism generating means 2 fixed to one end face thereof into the bearing inner ring 21 is shortened. The axial position of the inner surface of the inner ring 21 on the arrangement side of the rotation detecting device 1 is retreated to the inner side, and the axial position of the width surface portion 27c serving as the sensor mounting position of the sensor mounting member 27 is aligned with the flange portion 27b. Further, the output cable 29 drawn out from the sensor mounting member 27 is flat such as a flat cable. Other configurations are the same as those in FIG.

  In the case of this embodiment, the axial position of the rotation detection device 1 is closer to the rolling bearing 20 than in the embodiment of FIG. 1, and the amount of the output cable 29 that projects in the axial direction from the sensor mounting member 27 is also the same. As a result, the overall axial dimension of the bearing with the rotation detection device can be further shortened.

  FIG. 15 shows still another embodiment of the present invention. In the bearing with the rotation detection device of this embodiment, in the embodiment of FIG. 1, the insertion length to the bearing inner ring 21 of the rotating shaft 10 to which the magnetic generating means 23 is fixed to one end face is shortened as in the case of FIG. is doing. In addition, the axial position of the width surface portion 27c, which is the sensor mounting position of the sensor mounting member 27, is aligned with the flange portion 27b, and a magnetic force is applied to the inner diameter side of the bearing inner ring 21 via a separate fixing member 15 that is not shared by the rotary shaft 10. The generating means 2 is attached. The fixing member 15 is a disc-shaped member having a cylindrical portion 15 a at the periphery, and is fixed to the inner diameter side of the inner ring 21 by press-fitting or bonding the cylindrical portion 15 a to the inner diameter surface of the inner ring 21. The magnetism generating means 2 is fixed at the center position on one side of the fixing member 15 facing the rotation sensor 3 (corresponding to the rotation center O of the rolling bearing 20).

  Also in this embodiment, since the axial position of the rotation detection device 1 is closer to the rolling bearing 20 than in the embodiment of FIG. 1, the overall axial dimension of the bearing with the rotation detection device is further shortened. it can. In particular, in this embodiment, the magnetism generating means 2 is fixed to the fixing member 15 that is separate from the rotating shaft 10, so that the rotating shaft 10 can be separated from the bearing with the rotation detection device, The axial length can be shortened compared to the conventional example.

  FIG. 16 shows still another embodiment of the present invention. In the bearing with the rotation detection device of this embodiment as well, in the embodiment of FIG. 1, the insertion length of the rotating shaft 10 to which the magnetism generating means 2 is fixed to one end face into the bearing inner ring 21 is shortened as in the case of FIG. In addition, the magnetism generating means 2 is attached to the inner diameter side of the bearing inner ring 21 via a separate fixing member 15 that is not shared by the rotary shaft 10. The fixing member 15 has a disk shape, and has a flange portion 15b on the periphery of one surface opposite to the one surface facing the rotating shaft 10. By press-fitting a small diameter portion, which is a non-flange portion of the fixing member 15, into the inner diameter surface of the inner ring 21 so that the flange portion 15 b comes into contact with the width surface of the bearing inner ring 21 on the rotation detection device arrangement side. Fixed to.

  In the case of this embodiment, the fixing member 15 can be easily positioned on the inner diameter side of the inner ring 21 using the width surface of the inner ring 21 as a reference plane. As a result, the fixing member 15 is arranged such that the fixing surface of the magnetic generating means 2 in the fixing member 15 is perpendicular to the axis O of the rolling bearing 20, that is, the magnetic generating means 2 is parallel to the rotation sensor 3. Can be press-fitted into the inner ring 21. Therefore, the parallelism and clearance between the magnetism generating means 2 and the rotation sensor 3 can be maintained at a predetermined accuracy. As a result, it is possible to suppress fluctuation of the strength of the magnetic field pattern on the surface of the semiconductor chip 4 constituting the rotation sensor 3 due to the rotation of the magnetism generating means 2. Further, since the clearance can be made smaller than in the conventional case, the magnetic field sensed by the rotation sensor 3 is increased, and the S / N ratio is improved accordingly. With these two effects, the rotation detection accuracy of the rotation detection device 1 can be improved.

  FIG. 17 shows still another embodiment of the present invention. In the embodiment shown in FIG. 1, the bearing with a rotation detection device according to this embodiment is configured such that the rolling bearing 20 is a double row angular ball bearing, and one row of rolling elements 24 is between the rolling surfaces of the inner ring 21 and the outer ring 22. The other one row of rolling elements 24 is interposed between the rolling surfaces of the rotating shaft 10 and the outer ring 22. Other configurations are the same as those in the embodiment of FIG.

  FIG. 18 shows still another embodiment of the present invention. The bearing with a rotation detector of this embodiment uses a two-stage rotating shaft 10A instead of the single rotating shaft 10 in the embodiment of FIG. That is, the rotation shaft 10A in this case is composed of the rotation shaft main body 16 and the rotation shaft end body 17, and one end of the rotation shaft main body 16 is fitted into the cylindrical portion 17a of one end of the rotation shaft end body 17. The rotation shaft main body 16 and the rotation shaft end body 17 are connected by being stopped by the stopper 18. The rotating shaft end body 17 is fitted to the inner ring 21 of the rolling bearing 20, and the magnetism generating means 2 is fixed to the end surface of the rotating shaft end body 17. Other configurations are the same as those in the embodiment of FIG.

  In the case of this embodiment, since the rotating shaft main body 16 and the rotating shaft end body 17 are separable, the bearing with a rotation detector can be separated from the rotating shaft main body 16.

  FIG. 19 shows still another embodiment of the present invention. The bearing with a rotation detection device of this embodiment also uses a two-stage rotating shaft 10A in place of the single rotating shaft 10 in the embodiment of FIG. That is, the rotating shaft 10A in this case is also composed of the rotating shaft main body 16 and the rotating shaft end body 17, and one end of the rotating shaft end body 17 is fitted into the cylindrical portion 16a at one end of the rotating shaft main body 16. The rotation shaft main body 16 and the rotation shaft end body 17 are connected to each other by stopping the rotation with the stopper 19. Other configurations are the same as those in FIG.

  FIG. 20 shows still another embodiment of the present invention. In the embodiment shown in FIG. 16, the bearing with the rotation detection device of this embodiment is arranged on the inner diameter side of the rotation detection device installation side in the inner ring 21 of the rolling bearing 20 instead of forming the flange portion 15 b on the fixing member 15. The fixing member 15 is fixed to the inner ring 21 by forming the step portion 21a and press-fitting or bonding the fixing member 15 to the step portion 21a. In this case, the fixing member 15 is positioned in the axial direction with the step surface 21aa facing the axial direction of the step portion 21a of the inner ring 21 as a reference surface.

  In the case of this embodiment, the fixing member 15 is fixed to the inner ring 21 by being press-fitted or bonded to the stepped portion 21a of the inner ring 21, so that it corresponds to the approximate thickness of the fixing member 15 as compared with the case of the embodiment of FIG. Accordingly, the axial position of the fixing member 15 can be brought closer to the rotating shaft 10 side, and the overall axial length of the bearing with the rotation detecting device can be shortened.

  FIG. 21 shows still another embodiment of the present invention. The bearing with a rotation detection device of this embodiment employs the assembly structure of FIG. 10 for fixing the magnetic generating means 2 to the fixing member 15 in the embodiment of FIG. That is, a recess 15c is formed on one surface of the fixing member 15 facing the rotation sensor 3, and the magnetism generating means (permanent magnet) 2 is inserted and fixed in the recess 15c.

It is sectional drawing of the bearing with a rotation detection apparatus concerning one Embodiment of this invention. It is an enlarged side view which shows the fixing | fixed part of the magnetic generation means in the bearing. It is a top view of the semiconductor chip which constitutes an example of the rotation sensor in the bearing. It is explanatory drawing of the angle calculation process by the conversion circuit of the rotation sensor. It is a wave form diagram which shows the output of the magnetic sensor array in the rotation sensor. It is a top view of a semiconductor chip which constitutes another example of a rotation sensor in a bearing with a rotation detector. It is an output waveform diagram of the magnetic sensor element in the same rotation sensor. (A) is an enlarged view which shows an example of the fixing | fixed part of the magnetic generation means in a bearing with a rotation detection apparatus, (B) is a front view of the magnetic generation means. (A) is an enlarged side view showing another example of the fixing portion of the magnetic generation means in the bearing, and (B) is a front view of the magnetic generation means. (A) is an exploded side view of still another example of the fixing portion of the magnetic generation means in the bearing, and (B) is a side view of the fixed state of the magnetic generation means. (A) is an expanded side view which shows another example of the fixing | fixed part of the magnetic generation means in the bearing, (B) is a front view of the magnetic generation means. It is an expanded side view which shows another example of the fixing | fixed part of the magnetic generation means in the same bearing. It is an enlarged side view which shows another example of the fixing | fixed part of the magnetic generation means in the bearing. It is sectional drawing of the bearing with a rotation detection apparatus concerning other embodiment of this invention. It is sectional drawing of the bearing with a rotation detection apparatus concerning further another embodiment of this invention. It is sectional drawing of the bearing with a rotation detection apparatus concerning further another embodiment of this invention. It is sectional drawing of the bearing with a rotation detection apparatus concerning further another embodiment of this invention. It is sectional drawing of the bearing with a rotation detection apparatus concerning further another embodiment of this invention. It is sectional drawing of the bearing with a rotation detection apparatus concerning further another embodiment of this invention. It is sectional drawing of the bearing with a rotation detection apparatus concerning further another embodiment of this invention. It is sectional drawing of the bearing with a rotation detection apparatus concerning further another embodiment of this invention. It is sectional drawing of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotation detection apparatus 2 ... Magnetic generation means 2A, 2B, 2C ... Permanent magnet 3, 3A ... Rotation sensor 4 ... Semiconductor chip 5a, 5b ... Magnetic sensor element 5A-5D ... Magnetic line sensor 6 ... Conversion circuit (calculation means)
DESCRIPTION OF SYMBOLS 10, 10A ... Rotary shaft 10a ... Recessed part 11 ... Resin member 13 ... Magnetic material yoke 13a ... Recessed part 15 ... Fixed member 20 ... Rolling bearing 21 ... Inner ring 22 ... Outer ring

Claims (13)

A rotation sensor that has magnetism generating means having directionality around the center of rotation on the inner ring side of the bearing and outputs rotation or angle information by detecting the magnetism of the magnetism generating means on the outer ring side is located at the bearing axis. Mounted with a rotation detection device,
A bearing with a rotation detecting device, wherein the magnetism generating means is fixed to a fixing member fixed to the inner diameter side of the inner ring of the bearing.   The bearing with a rotation detection device according to claim 1, wherein the fixing member is a shaft.   2. The bearing with a rotation detection device according to claim 1, wherein the fixing member is a member different from the shaft and is fixed to the inner ring inner diameter surface by press-fitting or bonding.   The bearing with a rotation detecting device according to claim 3, wherein the fixing member is positioned by contacting the end surface of the inner ring or a stepped surface facing the axial direction processed into the inner ring.   The bearing with a rotation detector according to any one of claims 1 to 4, wherein the magnetism generating means is composed of two permanent magnets magnetized in the axial direction.   5. A bearing with a rotation detection device according to claim 1, wherein the magnetism generating means is a single permanent magnet having both N and S poles on one side.   The bearing with a rotation detecting device according to claim 5 or 6, wherein a recess is provided in the fixing member, and a permanent magnet is fixed in the recess.   The bearing with a rotation detecting device according to claim 7, wherein the permanent magnet is surrounded by a flexible material such as a resin that is more flexible than the magnetism generating means and the fixing member, and the flexible material is fixed together with the permanent magnet in the recess. .   9. The bearing with a rotation detection device according to claim 1, wherein the fixing member is a non-magnetic member, and a magnetic yoke is sandwiched between the magnetism generating means and the fixing member.   10. The rotation sensor according to claim 1, wherein the rotation sensor is a combination of a plurality of magnetic sensor elements and means for converting the output of the magnetic sensor elements into a rotation signal or an angle signal. Bearing with rotation detector.   The bearing with a rotation detection device according to claim 10, wherein the rotation sensor is integrated on a semiconductor chip.   12. The rotation sensor according to claim 11, wherein the rotation sensor includes a four-side magnetic line sensor in which magnetic sensor elements are arranged along four sides of a virtual rectangle, and a magnetic line sensor is provided inside the rectangular arrangement of the magnetic line sensor. A bearing with a rotation detection device in which calculation means for converting the sensor output of the line sensor into rotation information or angle information is arranged. 12. The magnetic sensor according to claim 11, wherein the plurality of magnetic sensors inside the rotation sensor detect a sine signal and a cosine signal of a magnetic field that is rotated by rotation of the magnetism generating means, and the conversion circuit detects the magnetic sensor. A bearing with a rotation detection device having a calculation means for converting the converted signal into a rotation signal or an angle signal.

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