JP2007057236A - Bearing with multi-rotation absolute angle detecting function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing with a multi-rotation absolute angle detecting function for accurately performing multi-rotation absolute angle detection while avoiding the effect of an external magnetic field and the internal magnetic interference of respective rotation detection parts with each other, and realizing miniaturization. <P>SOLUTION: This bearing with a multi-rotation absolute angle detecting function is made by mounting bearing parts 21a and 21B with a multi-rotation absolute angle detecting mechanism 31 for detecting the number of rotations equal to or more than one rotation and an absolute angle of rotation. The detecting mechanism 31 comprises a one-rotation detecting part 18 for detecting the rotational angle of one rotation of relative rotation between the inner and outer rings of the bearing parts 21a and 21B, and a multi-rotation detecting part 3 for detecting the number of rotations equal to or more than one rotation of the relative rotation. The detecting mechanism 31 is provided with an external magnetic field shield material 11 for shielding itself from a magnetic field acting from the exterior. The shield material 11 is provided with a gap 11a between the detecting part 18 and the detecting part 3. The shield material 11 also serves as a stator housing of the detecting mechanism 31. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bearing with a multi-rotation absolute angle detection function that detects an absolute steering angle of a steering.

  As a mechanism for detecting the rotation angle as an absolute angle, a detected part whose magnetic characteristics are changed with one rotation as one cycle is attached to the rotating side race ring of the bearing, and the detected part is attached to the fixed side race ring of the bearing. There has been proposed an apparatus in which a magnetic sensor is mounted oppositely and an absolute rotation angle is detected without performing an initialization operation when power is turned on (Patent Document 1).

  In addition, as a mechanism for detecting the absolute angle of multiple rotations, a detected part whose magnetic characteristics have been changed with one rotation as one cycle is attached to the bearing cage, and the detected part is mounted on the fixed-side bearing ring of the bearing. A magnetic sensor is mounted oppositely, and the cage has been proposed to detect the rotation absolute angle of the rotation side raceway over multiple revolutions by utilizing the fact that the cage rotates at a lower speed than the rotation side raceway. (Patent Document 2).

As another multi-rotation absolute angle detection mechanism, it is configured to detect the multi-rotation absolute angle of the object directly connected to the input shaft of the planetary gear mechanism by detecting the rotation of the output shaft of the planetary gear mechanism with a sensor. This has also been proposed (Patent Document 3).
Japanese Patent Laid-Open No. 2004-4028 JP 2004-308724 A JP 2002-340545 A

However, with the configuration disclosed in Patent Document 1, only an absolute angle of one rotation can be detected.
In addition, in the configuration disclosed in Patent Document 2 in which the detected part is attached to the cage, the rolling element may slip during rotation or when rotation is stopped / started, so that it is difficult to accurately detect the absolute angle.
In the configuration starting from Patent Document 3 using a planetary gear mechanism, the number of gears increases, and how to support these gears (especially planetary gears) becomes an issue. Further, when trying to increase the reduction ratio, the radial space of the mechanism increases.

In order to solve such problems of the conventional example, a bearing with a multi-rotation absolute angle detection function configured as shown in FIGS. 7 and 8 has been proposed (Japanese Patent Application No. 2005-152378). In this bearing with a multi-rotation absolute angle detection function, a multi-rotation detection mechanism 41 and a single-rotation detection mechanism 48 are provided between a pair of left and right rolling bearings 61A and 61B. The one-rotation detection mechanism 48 includes a detected portion 58 including a magnetic encoder attached to the inner ring 62B, and a detection portion 59 that detects this.
The multi-rotation detection mechanism 41 includes a speed reduction mechanism 42 and a multi-rotation detector 43. Between both rolling bearings 61A and 61B, a stator housing 51 is provided across outer rings 63A and 63B that are fixed side races, and a rotor housing 50 is provided across inner rings 62A and 62B that are rotational side races. ing. The stator housing 51 is made of a nonmagnetic material, and a ferromagnetic external magnetic field shield material 57 is provided outside the stator housing 51.

  The speed reduction mechanism 42 is attached to the outer periphery of the rotor housing 50 and rotates together with the inner rings 62A and 62B. The internal toothed member 45 attached to the inner periphery of the stator housing 51, and the internal toothed member 45. The externally toothed member 46 is engaged with the externally toothed member 46 and the speed reducing member 47 is rotated and transmitted from the externally toothed member 46. The externally toothed member 46 meshes with the internally toothed member 45 and rotates at a reduction ratio 1 / L (an arbitrary value greater than or equal to 1) on the eccentric rotation center O ′, which is the rotation center of the eccentric ring 44. The speed reduction member 47 is rotatably provided on the outer periphery of the rotor housing 50, and decelerates and rotates at a speed reduction ratio of 1 / L on the rotation center O of the rotation side race rings 62A and 62B at a speed equal to the rotation of the externally toothed member 46. . The multi-rotation detector 43 is a rotation detector that outputs one sine wave or sawtooth wave per rotation, and includes a detected portion 54 such as a magnetic encoder provided in the speed reduction member 47, and a stator housing 51. And a detection unit 55 that is attached to the periphery and detects the detected unit 54.

  According to the above configuration, the internal mesh planetary gear mechanism including the eccentric ring 44, the internally toothed member 45, and the externally toothed member 46 and the constant speed internal gear mechanism including the externally toothed member 46 and the speed reducing member 47 are high. Since the reduction mechanism of the reduction ratio is configured, it can be configured as a compact shaft-through type, and a wide range of multi-rotation absolute angle detection can be performed. In addition, since the one-rotation detection mechanism 48 is also provided, a more advanced multi-rotation can be performed based on the rotation speed of the rotation-side race wheels 62A and 62B determined by the multi-rotation detection mechanism 41 and the output signal of the one-rotation detection mechanism 48. Absolute angle detection can be performed.

Further, the proposed example in the figure devise both the shield of the external magnetic field and the avoidance of interference between the internal magnets as follows. That is, when a stator housing is made of a ferromagnetic material for the external magnetic field shield, the detected portion 54 including the magnetic encoder of the internal multi-rotation detection mechanism 41 and the single-rotation detection mechanism 48, etc. for the stator housing, There is a problem that the magnetic interference between the 58s increases and the absolute position detection accuracy deteriorates. Therefore, in order to increase the distance between the external magnetic field shield 57 that is a ferromagnetic material and the detected portions 54 and 58 that are magnets, the stator housing 51 is made of a nonmagnetic material, and the external magnetic field shield material 57 that is a ferromagnetic material on the outside thereof. Is provided.
Thereby, it is avoided that the detection accuracy of the multi-rotation absolute angle detection mechanism is lowered by the external magnetic field. In addition, since the distance between each of the detected portions 54 and 58 and the external magnetic field shield material 57 is increased, the magnetic interference between the internal detected portions 54 and 58 caused by the external magnetic field shield material 57 can be reduced.
However, the reduction of the magnetic interference between the detected parts 54 and 58 inside due to the external magnetic field shielding material 57 is not sufficient. Further, the above configuration in which the external magnetic field shielding material 57 is provided outside the stator housing 51 has a problem that the outer diameter becomes large.

An object of the present invention is to provide a bearing with a multi-rotation absolute angle detection function capable of accurately performing multi-rotation absolute angle detection by reducing the influence of an external magnetic field and magnetic interference between internal rotation detection units. That is.
Another object of the present invention is to effectively provide an external magnetic field shielding material to reduce the size.

A bearing with a multi-rotation absolute angle detection function according to the present invention includes a bearing portion having an outer ring and an inner ring that are rotatable relative to each other via rolling elements, a one-rotation detection unit that detects a rotation angle of one rotation of the relative rotation, and A multi-rotation detection unit configured to detect a rotation number of one or more relative rotations and provided with a multi-rotation absolute angle detection mechanism that magnetically detects the rotation number of one rotation or more and the absolute angle of rotation. In the bearing with a rotation absolute angle detection function, the multi-rotation absolute angle detection mechanism is provided with an external magnetic field shield material for shielding a magnetic field acting from the outside, and the one-rotation detection unit and the multi-rotation detection unit are provided on the external magnetic field shield material. A gap is provided between the two.
According to this configuration, since the external magnetic field shielding material is provided, it is possible to prevent the detection accuracy of the multi-rotation absolute angle detection mechanism from being lowered by the external magnetic field. In addition, since the external magnetic field shield material has a gap between the single rotation detection unit and the multiple rotation detection unit, without increasing the magnetic interference between the internal rotation detection units by interposing the external magnetic field shield material, External magnetic field shielding can be performed. Thereby, highly accurate multi-turn absolute angle detection can be performed.

  The external magnetic field shielding material may be a stator housing of a multi-turn absolute angle detection mechanism. When the external magnetic field shielding material is a stator housing of a multi-rotation absolute angle detection mechanism, it is not necessary to provide an external magnetic field shielding material as a separate member from the stator housing. Can be reduced.

In the present invention, an internal magnetic field shielding material for preventing interference between the single rotation detection unit and the multiple rotation detection unit may be provided, and a nonmagnetic material may be provided between the external magnetic field shielding material and the internal magnetic field shielding material. .
When the internal magnetic field shielding material is provided, interference between the one-rotation detection unit and the multi-rotation detection unit can be prevented, so that more accurate multi-rotation absolute angle detection can be performed. In addition, by providing a non-magnetic material between the internal magnetic field shield material and the external magnetic field shield material, the flow of magnetic flux between the internal magnetic field shield material and the external magnetic field shield material can be interrupted, and the magnetic fields of both detection units can be blocked. Interference can be reduced.

Also, in the present invention, an internal magnetic field shielding material for preventing interference between the one-rotation detection unit and the multi-rotation detection unit is provided, and the internal magnetic field shielding materials are respectively connected to the one-rotation detection unit side and the multi-rotation detection unit side. It may be composed of a plurality of divided internal magnetic field shield materials divided so as to be positioned at each other, and a nonmagnetic material or a gap may be interposed between these divided internal magnetic field shield materials.
By dividing the internal magnetic field shielding material in this way and interposing a non-magnetic material or a gap between the two divided internal magnetic field shielding materials, each of which is a magnetic material, the flow of magnetic flux between the one-rotation detection unit and the multi-rotation detection unit is increased. The magnetic interference between the two detection units can be further reduced.

  In the present invention, the one-rotation detection unit and the multi-rotation detection unit are provided side by side in the axial direction of the bearing unit, and the one-rotation detection unit and the multi-rotation detection unit are respectively a detection target to be rotated and the detection target. A detecting portion for detecting the portion, and each detecting portion may be installed on a member fixed to the outer ring of the bearing portion. When the one-rotation detection unit and the multi-rotation detection unit are provided side by side in the axial direction of the bearing unit, the entire bearing with the multi-rotation absolute angle detection function can be made compact and simple. Further, as described above, it is possible to reduce the magnetic interference between the two rotation detection units by providing a gap in the external magnetic field shielding material with a simple configuration.

A bearing with a multi-rotation absolute angle detection function according to the present invention includes a bearing portion having an outer ring and an inner ring that are rotatable relative to each other via rolling elements, a one-rotation detection unit that detects a rotation angle of one rotation of the relative rotation, and A multi-rotation detection unit configured to detect a rotation number of one or more relative rotations and provided with a multi-rotation absolute angle detection mechanism that magnetically detects the rotation number of one rotation or more and the absolute angle of rotation. In the bearing with a rotation absolute angle detection function, the multi-rotation absolute angle detection mechanism is provided with an external magnetic field shield material for shielding a magnetic field acting from the outside, and the one-rotation detection unit and the multi-rotation detection unit are provided on the external magnetic field shield material. Therefore, the influence of the external magnetic field and the magnetic interference between the internal rotation detectors can be reduced, and high-precision multi-rotation absolute angle detection can be performed.
When the external magnetic field shielding material is a stator housing of a multi-turn absolute angle detection mechanism, it is not necessary to provide an external magnetic field shielding material as a separate member from the stator housing, and magnetic interference can be achieved by providing a gap as described above. Therefore, the entire outer diameter can be reduced while sufficiently preventing magnetic interference.

  A first embodiment of the present invention will be described with reference to FIGS. This bearing A with a multi-rotation absolute angle detection function is used, for example, as a steering angle sensor for steering. In this bearing A with a multi-rotation absolute angle detection function, a multi-rotation absolute angle detection mechanism comprising a multi-rotation detection mechanism 1 and a single rotation detection mechanism 8 is installed between two rolling bearing portions 21A and 21B arranged in the axial direction. It is a thing. Each rolling bearing portion 21A, 21B has inner rings 22A, 22B, outer rings 23A, 23B, and rolling elements 24. In this embodiment, the rotating bearing rings 21A and 21B of the rolling bearing portions 21A and 21B are inner rings 22A and 22B, the stationary bearing rings are outer rings 23A and 23B, and the rolling elements 24 are balls. It is press-fitted and fixed.

  The multi-rotation detection mechanism 1 includes a speed reduction mechanism 2 and a multi-rotation detection unit 3. The speed reduction mechanism 2 is a mechanism that converts the rotation of the rotation-side raceways 22A and 22B into a speed reduction rotation. The multi-rotation detection unit 3 is a mechanism that detects the deceleration rotation converted by the deceleration mechanism 2. The speed reduction mechanism 2 includes an eccentric ring 4 that is fixed to the inner rings 22A and 22B and rotates together with the inner rings 22A and 22B, an inner toothed member 5 that is mounted concentrically with the rotary shaft 30 on the outer rings 23A and 23B, and outer teeth. It consists of a member 6 and a deceleration member 7. The externally toothed member 6 is a member that rotates around the eccentric rotation center O ′ of the eccentric ring 4 by meshing with the internally toothed member 5. The speed reduction member 7 is a member that is rotatably provided around the rotation center O of the rotation shaft 30 on the inner ring 22A, 22B side, is rotated from the external toothed member 6, and rotates at a speed equal to that of the external toothed member 6. .

Between the inner rings 22A and 22B of the two rolling bearing portions 21A and 21B, the cylindrical rotor housing 10 is fixed by press-fitting between the inner peripheral portions of the opposing ends. The eccentric ring 4 is fixed at a position near the rolling bearing portion 21A on the outer periphery of the rotor housing 10 by press-fitting or bonding. In the eccentric ring 4, the outer peripheral surface is eccentric with respect to the inner peripheral surface fitted to the rotor housing 10, and the eccentric rotation center O ′ that is the center of the outer peripheral surface is offset with respect to the axial center O of the rotary shaft 30. Position. Thereby, when the eccentric ring 4 rotates with the rotating shaft 30, the outer peripheral surface performs eccentric rotation.
The externally toothed member 6 is formed of a spur gear having outward teeth and is rotatably provided on the outer periphery of the eccentric ring 4 so as to rotate about the eccentric rotation center O ′.

Between the outer rings 23A and 23B of the two rolling bearing portions 21A and 21B, an external magnetic field shield material 11 made of a ferromagnetic material is fixed by press-fitting between the outer peripheral portions of the opposing ends. A minute gap 11 a is provided in the magnetic shielding material 11 between the multi-rotation detection mechanism 1 and the single-rotation detection mechanism 8. The external magnetic field shielding material 11 is a member that shields the magnetic field that acts on the multi-rotation absolute angle detection mechanism 31 from the outside, and also serves as a stator housing that houses the multi-rotation absolute angle detection mechanism 31.
The inner toothed member 5 is fixed by press-fitting or bonding at a position facing the outer toothed member 6 on the inner periphery of the external magnetic field shield material 11. The internal toothed member 5 is composed of an internal gear having inward teeth. The external magnetic field shielding material 11 is fixed to the outer circumferences of the outer rings 23A and 23B, and the rotor housing 10 is fixed to the inner circumferences of the inner rings 22A and 22B by welding or bonding instead of press-fitting. good.

The outward teeth of the externally toothed member 6 mesh with the inwardly facing teeth of the internally toothed member 5, so that the externally toothed member 6 rotates around the eccentric rotation center O ′ along with the rotation of the internal rings 22A and 22B. The motor rotates at a reduced speed in a direction opposite to the rotation direction of 22A and 22B at a predetermined reduction ratio 1 / L (L: arbitrary value of 1 or more). The relationship between the internally toothed member 5 and the externally toothed member 6 in this case constitutes an intermeshing planetary gear mechanism that is generally well known. If the number of teeth of the externally toothed member 6 is Z1, and the number of teeth of the internally toothed member 5 is Z2, the reduction ratio is (Z2 -Z1) / Z1. Here, the externally toothed member 6 and the internally toothed member 5 having a small difference in the number of teeth are engaged and decelerated, but if the teeth are engaged, the toothed member 5 and the externally toothed member 6 The tooth shape may be anything.
On one side surface of the externally toothed member 6, a plurality of engagement pins 12 protruding in the axial direction are equally arranged with a predetermined interval in the circumferential direction.

  The speed reduction member 7 is an annular member that is rotatably fitted on the outer periphery of the rotor housing 10, and includes a cylindrical portion 7a that fits on the outer periphery of the rotor housing 10, and a flange portion that extends from one end of the cylindrical portion 7a to the outer diameter side. 7b. The speed reduction member 7 is disposed adjacent to the eccentric ring 4 so that the flange portion 7b faces the engaging pin 12 of the external toothed member 6 in the axial direction.

On the side surface of the speed reduction member 7 facing the externally toothed member 6 of the flange portion 7b, as shown in FIG. Open and equally distributed. The guide recess 13 is formed in a circular hole having a diameter sufficiently larger than the shaft diameter of the engagement pin 12 so that the displacement of the engagement pin 12 rotating around the eccentric rotation center O ′ is allowed in the guide recess 13. ing. In this way, the engagement pin 12 of the external toothed member 6 engages with the guide recess 13 of the speed reduction member 6, thereby decelerating around the axis O of the rotary shaft 30 at a speed equal to the rotation of the external toothed member 6. The member 7 rotates. In this case, the relationship between the externally toothed member 6 and the speed reduction member 7 constitutes a generally known constant speed internal gear mechanism.
In this mechanism, the engagement pin 12 may be provided in the speed reduction member 7 and the guide recess 13 may be provided in the externally toothed member 6.

  Since the externally toothed member 6 rotates at a reduced speed around the eccentric rotation center O ′, it is difficult to directly detect this rotational angle. However, the rotation of the externally toothed member 6 causes the rotational axis 30 to rotate about the axis O of the rotating shaft 30. Since it is transmitted to the speed reduction member 7 that rotates around, the speed reduction rotation of the externally toothed member 6 can be easily detected indirectly by detecting the rotation of the speed reduction member 7.

  The multi-rotation detection unit 3 includes a detected portion 14 provided on the outer periphery of the cylindrical portion 7 a of the speed reduction member 7, and an inner portion of the outer magnetic field shielding material 11 on the outer rings 23 </ b> A and 23 </ b> B so as to face the detected portion 14. It consists of the detection part 15 provided in the circumference. In the multi-rotation detection unit 3, the detection unit 15 outputs a single sine wave or sawtooth wave while the deceleration member 7 makes one rotation. The multi-rotation detection unit 3 is configured using, for example, a sensor housing in which a magnetic encoder is disposed as the detected portion 14 and a Hall IC is disposed as the detection portion 15 with a 90 ° phase difference. Alternatively, for example, a resolver rotor is used as the detected portion 14, and a resolver stator is used as the detecting portion 15. FIG. 1 shows an example in which the detected part 14 is a magnetic encoder and the detecting part 15 is a sensor housing in which Hall ICs are arranged with a 90 ° phase difference. In this case, the sensor housing may be integrally formed with a resin mold together with the Hall IC. The magnetic encoder serving as the detected portion 14 is composed of a permanent magnet.

  As shown in FIG. 4, the rotation of the speed reduction member 7 is brought into contact with the outer periphery of the flange portion 7 b of the speed reduction member 7 and the inner periphery of the external magnetic field shield material 11 facing the radial direction, thereby detecting the rotation of the speed reduction member 7. If the pair of engaging portions 16 and 17 that are limited within the range of one rotation capable of detecting the absolute angle 3 is provided, the rotation range can be limited.

  The one-rotation detection mechanism 8 detects one rotation of the rotating shaft 30 and includes a one-rotation detection unit 18, a rotor housing 10 that supports this, and an external magnetic field shield material 11. The one-rotation detection unit 18 includes a detection unit 19 provided on the outer periphery of the rotor housing 10 and a detection unit 20 provided on the inner periphery of the external magnetic field shield material 11 so as to face the detection unit 19. While the rotation shaft 30 makes one rotation, the detection unit 20 outputs n peaks (n = 1, 2, 3,...) (That is, n is a natural number) sine waves or sawtooth waves. The one-rotation detection unit 18 is configured using, for example, a sensor housing in which a magnetic encoder is used as the detection unit 19 and a Hall IC is arranged as a detection unit 20 with a 90 ° phase difference. Alternatively, for example, a resolver rotor is used as the detected portion 19 and a resolver stator is used as the detecting portion 20. FIG. 1 shows an example in which a magnetic encoder is used as the detected part 19 and a sensor housing in which Hall ICs are arranged with a 90 ° phase difference as the detecting part 20 is shown. The magnetic encoder serving as the detected portion 19 is composed of a magnet.

  Further, a spacer 25 is interposed between the outer ring 23A and the internally toothed member 5, and a spacer 26 is interposed between the internally toothed member 5 and the multi-rotation detecting portion detecting portion 15. Thereby, the axial positioning of the member 5 with an internal tooth and the detection part 15 for multiple rotation detection parts is achieved.

  Next, the operation of the multi-turn absolute angle detecting function bearing A having the above-described configuration will be described. When the rotating shaft 30 rotates, the externally toothed member 6 rotatably provided on the outer periphery of the eccentric ring 4 meshes with the internally toothed member 5, while the reduction ratio is 1 / L in the direction opposite to the rotating direction of the rotating shaft 30. Decelerate and rotate. The decelerated rotation is transmitted at a constant speed to a decelerating member 7 that is rotatably provided on the outer periphery of the rotor housing 10. The absolute angle within one rotation of the deceleration member 7 can be detected from the output waveform of the detection unit 15 of the multi-rotation detection unit 3. The rotation of the rotating shaft 30 is decelerated and rotated by the decelerating mechanism 2 at a reduction ratio of 1 / L and converted into the rotation of the reducing member 7, so that one rotation of the reducing member 7 corresponds to L rotation of the rotating shaft 30. Therefore, an absolute angle within L rotations of the rotary shaft 30 can be detected from the output waveform of the detection unit 15 of the multi-rotation detection unit 3.

  Thus, in this bearing A with a multi-rotation absolute angle detection function, the intermeshing planetary gear mechanism comprising the eccentric ring 4, the internally toothed member 5, and the externally toothed member 6, the externally toothed member 6 and the speed reducing member. Since the speed reduction mechanism 2 having a high speed reduction ratio is configured by the constant speed internal gear mechanism comprising 7, the multi-rotation absolute angle detection mechanism 31 can be configured in a compact shaft-through type, and a high speed reduction ratio can be obtained over a wide range. Multi-turn absolute angle detection is possible. In addition, the multi-rotation detection unit 3 can determine the number of rotations of the rotary shaft 30, and the one-rotation detection unit 18 can detect the absolute rotation angle of the rotary shaft 30 at 1 / n rotation intervals. Detection can be performed.

In this case, since the external magnetic field shielding material 11 is provided, it is avoided that the detection accuracy of the multi-rotation detection unit 3 and the single rotation detection unit 18 is reduced due to the external magnetic field.
The external magnetic field shield material 11 is made of a ferromagnetic material, and the external magnetic field shield material 11 is provided with a minute gap 11a between the multi-rotation detection unit 3 and the single-rotation detection unit 18, so that the multi-rotation absolute It is possible to prevent an increase in magnetic interference caused by the external magnetic field shield material 11 between the magnets serving as the detected portions 14 and 19 of the multi-rotation detection unit 3 and the one-rotation detection unit 18 constituting the angle detection mechanism. . This makes it possible to perform multi-turn absolute angle detection with higher accuracy.

  In this embodiment, since the external magnetic field shield material 11 also serves as the stator housing of the multi-turn absolute angle detection mechanism, it is not necessary to provide an external magnetic field shield material as a separate member from the stator housing, and the multi-turn absolute angle detection function The outer diameter of the bearing A is not increased.

  In this embodiment, the multi-rotation detector 3 and the single-rotation detector 18 are provided side by side in the axial direction of the bearing portions 21A and 21B, and the multi-rotation detector 3 and the single-rotation detector 18 are respectively rotated. The external magnetic field, which is a member having detection parts 14 and 19 and detection parts 15 and 20 for detecting the detected parts, and fixing the detection parts 15 and 20 to the outer rings 23A and 23B of the bearing parts 21A and 21B. Since the shield member 11 is installed, the entire bearing 31 with a multi-turn absolute angle detection function can be made into a compact and simple configuration with a small outer diameter. Further, as described above, it is possible to reduce the magnetic interference between the rotation detection units 3 and 18 by providing the gap 11a in the external magnetic field shielding material 11 with a simple configuration.

  FIG. 5 shows another embodiment of the present invention. This multi-rotation absolute angle detection function bearing B is provided with an internal magnetic field shielding material 27 made of a ferromagnetic material in order to prevent interference between the multi-rotation detection unit 3 and the single rotation detection unit 18 in the embodiment of FIG. A non-magnetic material 28 is provided between the internal magnetic field shielding material 27 and the external magnetic field shielding material 11. The internal magnetic field shielding material 27 is provided between the detection units 15 and 20 of the multi-rotation detection unit 3 and the single rotation detection unit 18 which are fixed side members, so that an inner diameter side portion of the internal magnetic field shielding material 27 is provided. It arrange | positions between the to-be-detected parts 14 and 19 of the multiple rotation detection part 3 which is a rotation side member, and the 1 rotation detection part 18. FIG. Other configurations are the same as those of the embodiment of FIG.

  In this embodiment, since the internal magnetic field shielding material 27 is provided between the multi-rotation detection unit 3 and the single-rotation detection unit 18, magnetic interference between the multi-rotation detection unit 3 and the single-rotation detection unit 18 can be further prevented. Therefore, it is possible to perform multi-turn absolute angle detection with higher accuracy. Furthermore, since the nonmagnetic material 28 is provided between the internal magnetic field shield material 27 and the external magnetic field shield material 11, the flow of magnetic flux between the internal magnetic field shield material 27 and the external magnetic field shield material 11 can be blocked, and only Magnetic interference between both the detection units 2 and 18 can be reduced.

FIG. 6 shows still another embodiment of the present invention. In the embodiment shown in FIG. 5, the multi-rotation absolute angle detection bearing C has a plurality of internal magnetic field shielding materials 27 divided so as to be positioned on the one-rotation detection unit 18 side and the multiple-rotation detection unit 3 side, respectively. The divided internal magnetic field shield materials 27A and 27B are divided, and a non-magnetic material 29 is pushed and interposed between the divided internal magnetic field shield materials 27A and 27B. Each divided internal magnetic field shielding material 27A, 27B is made of a magnetic material. Instead of interposing the non-magnetic material 29, an air gap may be interposed. Although the nonmagnetic material 28 between the internal magnetic field shield material 27 and the external magnetic field shield material 11 in the embodiment of FIG. 5 is omitted in this embodiment, each of the divided internal magnetic field shield materials 27A and 27B and the external magnetic field shield is provided. The nonmagnetic material 28 shown in FIG.
In this embodiment, the internal magnetic field shielding material 27 is divided, and the non-magnetic material 29 or the air gap is interposed between both divided internal magnetic field shielding materials 27A and 27B, which are magnetic materials. The flow of magnetic flux in the detection unit 3 is blocked, and the magnetic interference between the detection units 18 and 3 can be further reduced.

It is sectional drawing of the bearing with a multiple rotation absolute angle detection mechanism concerning 1st Embodiment of this invention. It is a side view of the bearing. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 1. It is a side view of the rotation range limitation mechanism in the bearing. It is sectional drawing of the bearing with a multiple rotation absolute angle detection mechanism concerning other embodiment of this invention. It is sectional drawing of the bearing with a multi-rotation absolute angle detection mechanism concerning further another embodiment of this invention. It is sectional drawing of a prior art example. It is the same side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Multi-rotation absolute angle detection mechanism 2 ... Deceleration mechanism 3 ... Multi-rotation detection part 8 ... 1-rotation detection mechanism 11 ... External magnetic field shielding material 11a ... Gap 14 ... Detected part 15 of a multi-rotation detection part ... Detection unit 18 ... 1 rotation detection unit 19 ... Detected unit 20 of 1 rotation detection unit ... Detection units 21A and 21B of 1 rotation detection unit ... Rolling bearings 22A and 22B ... Inner ring 23A and 23B ... Outer ring 24 ... Rolling element 27 ... Internal magnetic field shield material 27A, 27B ... split internal magnetic field shield material 28 ... nonmagnetic material 29 ... nonmagnetic material 31 ... multi-rotation absolute angle detection mechanism

Claims (5)

A bearing portion having an outer ring and an inner ring that are rotatable relative to each other via rolling elements, a one-rotation detecting unit that detects a rotation angle of one rotation of the relative rotation, and a rotation number of one or more rotations of the relative rotation are detected. In a bearing with a multi-rotation absolute angle detection function comprising a multi-rotation detection unit and comprising a multi-rotation absolute angle detection mechanism that magnetically detects the rotational speed of one rotation or more and the absolute angle of rotation,
An external magnetic field shielding material for shielding a magnetic field acting from the outside is provided in the multi-rotation absolute angle detection mechanism, and a gap is provided between the one-rotation detection unit and the multi-rotation detection unit in the external magnetic field shielding material. Bearing with multi-turn absolute angle detection function.   2. The bearing with a multi-rotation absolute angle detection function according to claim 1, wherein the external magnetic field shielding material is a stator housing of a multi-rotation absolute angle detection mechanism.   In Claim 1 or Claim 2, it has an internal magnetic field shielding material for preventing interference with a 1 rotation detection part and a multiple rotation detection part, and a nonmagnetic material is provided between an external magnetic field shielding material and an internal magnetic field shielding material. Provided bearing with multi-turn absolute angle detection function.   4. The method according to claim 1, further comprising an internal magnetic field shielding material for preventing interference between the one-rotation detection unit and the multi-rotation detection unit. Multi-rotation absolute angle detection function consisting of a plurality of divided internal magnetic field shield materials divided so as to be located on the side of the multi-rotation detector and the multi-rotation detection unit side, and a non-magnetic material or air gap interposed between these divided internal magnetic field shield materials bearing. In any one of Claims 1 thru / or 4, The 1 rotation detection part and the multiple rotation detection part are arranged along with the axial direction of the bearing part, The 1 rotation detection part and the multiple rotation detection part are A bearing with a multi-rotation absolute angle detection function that includes a detected part that rotates and a detecting part that detects the detected part, and each detecting part is installed on a member fixed to the outer ring of the bearing part.

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