JP2012007706A - Rolling bearing with sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing with a sensor capable of eliminating the effect of an external magnetic field resulting from external noise.SOLUTION: The rolling bearing with a sensor includes a rotating-side ring 2, a fixed-side ring 3, rolling elements 4 interposed between the rotating-side ring 2 and the fixed-side ring 3, a ring magnet 11 held on a magnet holder 12 fixed to the rotating-side ring, and a magnetic induction sensor 15 which is held by a sensor housing 16 fixed to the fixed-side ring and arranged opposite to the ring magnet 11 at a predetermined gap. The magnet holder 12 and the sensor housing 16 are formed of a magnetic substance. The magnet holder 12 and the sensor housing 16 are disposed so as to magnetically shield the gap between the ring magnet 11 and the magnetic induction sensor 15 from the outside.

Description

  The present invention relates to a rolling bearing with a sensor provided with a ring magnet and a magnetic sensor.

  As a rolling bearing with a sensor of this type, for example, as shown in FIG. 6, a sensor carrier 123 in which a sensor 121 is embedded is encircled in a concave groove 116b provided on an inner diameter surface of an outer ring 110 via a sensor holding device 125. With the sensor having a configuration in which the member 120 to be detected is arranged on the radial plane portion of the L-shaped member 122 press-fitted into the outer diameter surface of the inner ring 111 so as to face the sensor 121. A rolling bearing has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 3352791

Incidentally, in many cases, the sensor-equipped rolling bearing is generally disposed in the vicinity of a member that generates electric noise such as an electric motor. Therefore, depending on the mounting position, the external magnetic field caused by external noise may disturb the magnetic field formed by the member to be detected. In the conventional example described in Patent Document 1 described above, since the back surface of the sensor 121 is exposed to the outside from the sensor carrier 123, the external magnetic field caused by external noise is generated by the detected member 120. Therefore, there is an unsolved problem that the sensor 121 cannot accurately detect the magnetic field formed by the member 120 to be detected.
Therefore, the present invention has been made paying attention to the above-described unsolved problems of the conventional example, and provides a rolling bearing with a sensor capable of removing the influence of an external magnetic field caused by external noise. It is the purpose.

  In order to solve the above problems, a rolling bearing with a sensor according to an embodiment of the present invention includes a rotating side wheel, a fixed side wheel, a rolling element interposed between the rotating side wheel and the fixed wheel, and the rotating side. A ring magnet held by a magnet holder fixed to a ring; and a magnetic sensitive sensor held by a sensor housing fixed to the fixed side wheel and opposed to the ring magnet with a predetermined gap. The sensor housing is made of a magnetic material, and the magnet holder and the sensor housing are arranged so as to magnetically shield between the ring magnet and the magnetic sensitive sensor.

In a rolling bearing with a sensor according to another aspect of the present invention, the magnet holder is disposed so as to cover a bearing space between the rotating side wheel and the fixed side wheel, and the sensor housing covers the magnet holder. Thus, it is formed in a U-shaped cross section.
In the rolling bearing with a sensor according to another aspect of the present invention, the magnet holder includes at least an annular plate portion that covers the bearing space and a flange portion that contacts an outer diameter side of the ring magnet. It is said.

Moreover, the rolling bearing with a sensor which concerns on the other form of this invention is characterized by the said sensor housing fixing the said magnetic sensitive sensor by the mold part.
Further, in the rolling bearing with sensor according to another aspect of the present invention, the mold part has an annular projecting part extending in the vicinity of the opposite side across the flange part and the ring magnet, and the constant gap of the ring magnet is provided. It is characterized by a labyrinth formed around it.

  According to the rolling bearing with a sensor of the present invention, the magnet holder that holds the ring magnet and the sensor housing that holds the magnetic sensitive sensor are each made of a magnetic material, and the magnet holder and the sensor housing are between the ring magnet and the magnetic sensitive sensor. Since the magnetic field is shielded against the magnetic field from the outside, the external magnetic field caused by the external noise from the noise generation source such as the electric motor affects the predetermined gap between the ring magnet and the magnetic sensor. Can be reliably prevented and accurate rotation detection can be performed.

It is sectional drawing which shows 1st Embodiment of the rolling bearing with a sensor which concerns on this invention. It is a top view which shows the polar structure of a ring magnet. It is sectional drawing which shows a magnetic sensitive sensor and a board | substrate. It is sectional drawing which shows 2nd Embodiment of the rolling bearing with a sensor which concerns on this invention. It is sectional drawing which shows 3rd Embodiment of the rolling bearing with a sensor which concerns on this invention. It is sectional drawing which shows a prior art example.

Hereinafter, embodiments of a rolling bearing with a sensor according to the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention. In the figure, reference numeral 1 denotes a rolling bearing with a sensor that is applied to a rotating shaft of an automobile, a railway vehicle, an iron making facility, a machine tool, etc., and detects the rotational speed. The rolling bearing with sensor 1 is a rotating side wheel facing each other. The bearing inner ring 2 and the bearing outer ring 3 as a stationary side ring, and a large number of rolling elements 4 interposed between the bearing inner ring 2 and the bearing outer ring 3 constitute a rolling bearing 5. Here, each of the bearing inner ring 2 and the bearing outer ring 3 is formed with step portions 6 and 7 on the rolling element 4 side at a predetermined distance from both ends in the axial direction of the opposing surfaces.

A magnet holder 12 made of a magnetic material that holds the ring magnet 11 is fitted and held in the bearing inner ring 2. In addition, a sensor housing 16 made of a magnetic material that holds a magnetic sensitive sensor 15 such as a Hall element is fitted and held in the bearing outer ring 3 so as to cover the magnet holder 12.
The magnet holder 12 is press-fitted and fixed to the step portion 6 of the bearing inner ring 2 and slightly protrudes outward from the axial end portion of the bearing inner ring 2, and a radius from the axial protruding end portion of the cylindrical portion 12a. An annular plate portion 12b extending so as to cover a bearing space between the bearing inner ring 2 and the bearing outer ring 3 of the rolling bearing 5 in a direction, and a cylindrical shape protruding outward in the axial direction from the outer peripheral edge of the annular plate portion 12b. The flange portion 12c.

  The ring magnet 11 is fixed and held with, for example, an adhesive so as to come into contact with the annular plate portion 12b and the flange portion 12c and to be in a substantially central position in the radial direction of the bearing space. As shown in FIG. 2, the ring magnet 11 includes eight arc-shaped magnet pieces 11 a magnetized in the circumferential direction in the circumferential direction as viewed from above so that the adjacent magnetic poles have different polarities. They are connected to form a magnetized pattern in which N and S poles are alternately arranged in the circumferential direction.

  The sensor housing 16 includes an outer cylindrical portion 16a that is press-fitted and fixed to the step portion 7 of the bearing outer ring 3, and an annular plate portion 16b that extends radially inward from the outer end of the outer cylindrical portion 16a to the bearing inner ring 2. And the ring magnet 11 with the inner cylinder portion 16c extending from the inner end of the annular plate portion 16b toward the axial end portion of the bearing inner ring 2 and facing the bearing inner ring 2 with a slight gap therebetween. It is formed in a U-shaped cross section covering from the side.

  An annular substrate 17 on which the magnetic sensitive sensor 15 shown in FIG. 3 is mounted is attached to the sensor housing 16 so that the magnetic sensitive sensor 15 and the ring magnet 11 face the annular plate portion 16b at a predetermined interval. It is installed. Here, the magnetic sensitive sensor 15 is configured to detect the phase angle of each phase of the three-phase electric motor, and at least 1 to detect the rotational speed of the rotating shaft inserted into the bearing inner ring 2. Two magnetic sensitive sensors 15 may be arranged, and in order to detect the rotational speed and the rotational direction, the magnetic sensitive sensor 15 has a phase difference of 90 degrees with respect to the magnetization pattern of the ring magnet 11. What is necessary is just to arrange | position another magnetic sensitive sensor 15 '. The magnetic sensitive sensor 15 (or 15 and 15 ′) is covered with a synthetic resin mold 18, and a sensor gap 19 having a predetermined gap is formed between the opposed surfaces of the mold 18 and the ring magnet 11.

Therefore, the sensor gap 19 is surrounded from all sides by the magnet holder 12 and the sensor housing 16 made of a magnetic material.
In addition, the substrate 17 is provided with a signal processing circuit 20 for processing, for example, a sinusoidal electrical detection signal corresponding to the magnetic field intensity output from the magnetic sensor 15 in FIG. The signal-processed detection signal is output to an external rotational speed measuring device via the signal line 21.

Next, the operation of the above embodiment will be described.
Now, the bearing outer ring 3 of the rolling bearing 5 is fixed to a fixed part such as a housing, and a rotating shaft connected to a three-phase electric motor (not shown) such as a brushless motor is inserted into the bearing inner ring 2. State. When the three-phase electric motor is driven to rotate in this state, the bearing inner ring 2 is rotated in response to the rotation, and the ring magnet 11 is rotated, so that the magnetic sensitive sensor disposed to face the ring magnet 11. 15 detects a magnetic field corresponding to the magnetization pattern of the ring magnet 11 and outputs a detection signal, for example, a sine wave having a frequency corresponding to the rotational speed of the bearing inner ring 2.
This detection signal is signal-processed by a signal processing circuit 20 mounted on the substrate 17 to be converted into a pulse signal, and this pulse signal is output to an external rotational speed measuring device via a signal line 21. In this rotational speed measuring device, the rotational speed can be obtained by counting the number of pulse signals per unit time or measuring the pulse interval of the pulse signals.

In addition, when two magnetic sensitive sensors 15 are arranged, a sine wave signal having a phase difference of 90 degrees is output from the two sensitive sensors 15, so that the rotation direction is detected based on the phase difference between the two sensors 15. can do.
Thus, the rotational speed or the rotational speed and the rotational direction can be detected by detecting the magnetic field generated in the ring magnet 11 by the magnetic sensor 15, but as described above, the brushless motor or the like. When these three-phase electric motors are arranged close to each other, an external magnetic field caused by electrical noise generated by the three-phase electric motor may disturb the magnetic field formed by the ring magnet 11.

However, in the first embodiment, the magnet holder 12 and the sensor housing 16 are made of a magnetic material, and the magnet holder 12 and the sensor housing 16 define the ring magnet 11, the magnetic sensor 15 and the sensor gap 19 between them in all directions. To cover from.
Therefore, the ring magnet 11, the magnetic sensor 15 and the sensor gap 19 can be prevented from being exposed to the outside, and the magnet holder 12 and the sensor housing 16 can exhibit a function as a magnetic shield. With this magnetic shield function, changes in the external magnetic field caused by electrical noise generated by a three-phase electric motor or the like arranged in close proximity can be shielded, and the magnetic field generated by the ring magnet 11 is prevented from being disturbed by the external magnetic field. Thus, the magnetic sensor 15 can accurately detect the magnetic field generated in the ring magnet 11 and output an accurate detection signal.

Further, since the magnetic sensitive sensor 15 is mounted on the annular substrate 17, when a plurality of magnetic sensitive sensors 15 are arranged, they can be accurately arranged on the substrate 17 with a predetermined phase difference.
Furthermore, since the magnetic sensitive sensor 15 is covered with the mold 18, the IC part constituting the magnetic sensitive sensor 15 can be protected from the outside, and the dust resistance and waterproofness of the sensor IC part can be improved.

Next, a second embodiment of the present invention will be described with reference to FIG.
In the second embodiment, the path including the sensor gap 19 is made a labyrinth.
That is, in the second embodiment, as shown in FIG. 4, in the configuration of FIG. 1 in the first embodiment described above, the inner diameter of the mold 18 opposite to the flange portion 12 c of the magnet holder 12 of the ring magnet 11. 1 has the same configuration as that of FIG. 1 except that the cylindrical portion 18a is formed by projecting so as to face and face the annular plate portion 12b of the magnet holder 12 and the same parts as those in FIG. Reference numerals are assigned and detailed description thereof is omitted.

  According to the second embodiment, the mold 18 is formed with the cylindrical portion 18 a that protrudes so as to face and face the inner surface of the ring magnet 11 and the annular plate portion 12 b of the magnet holder 12. For this reason, in addition to being able to protect the IC part constituting the magnetic sensor 15 by the mold 18 as in the first embodiment described above, the axial direction of the inner cylinder part 16c of the sensor housing 16 and the bearing inner ring 2 A gap portion 31a between the end surface, a gap portion 31b between the cylindrical portion 18a of the mold 18 and the annular plate portion 12b of the magnet holder 12, an outer diameter surface of the cylindrical portion 18a, and an inner diameter surface of the ring magnet 11 The labyrinth 31 is formed by the gap 31c between the two, the sensor gap 19, and the gap 31d between the flange 12c of the magnet holder 12 and the outer cylinder 16a of the sensor housing 16.

  Since the gaps 31a to 31d can be set to several mm or less, it is possible to prevent intrusion of foreign matters. Further, when a magnetic foreign substance from the outside enters the labyrinth, it is attracted by the inner peripheral surface of the ring magnet 11, so that it is possible to reliably prevent the sensor gap 19 from entering the rotation position detection surface. Intrusion into the inside of the rolling bearing 5 can be reliably prevented.

Next, a third embodiment of the present invention will be described with reference to FIG.
In the third embodiment, the attachment of the magnet holder 12 to the bearing inner ring 2 and the attachment of the sensor housing 16 to the bearing outer ring 3 are more reliably performed.
That is, in the third embodiment, as shown in FIG. 5, the step portions 6 and 7 of the bearing inner ring 2 and the bearing outer ring 3 are omitted in the configuration of FIG. In addition, a locking groove 41 is formed in the circumferential direction on the rolling element 4 side by a predetermined distance from the axial end surface of the outer diameter surface of the bearing inner ring 2, and a predetermined distance from the axial end surface of the inner diameter surface of the bearing outer ring 3. Only on the rolling element 4 side, a locking groove 42 is formed in the circumferential direction. Here, as the locking groove 41 and the locking groove 42, a seal groove of the rolling bearing 5 can be used. By using this seal groove, the groove is formed without any special processing. be able to.

The tip of the cylindrical portion 12a of the magnet holder 12 is fixed by being crimped to the locking groove 41 at a predetermined interval in the circumferential direction. Similarly, the tip of the outer cylindrical portion 16a of the sensor housing 16 is predetermined in the circumferential direction. It is fastened and fixed to the locking concave groove 42 at intervals.
Here, as described in Japanese Patent No. 4269642, the number of caulking locations of the cylindrical portion 12a and the outer cylindrical portion 16a is n as a positive integer, Z as the number of rolling elements 4, and an integer equal to or greater than 2. X
(Number of caulking points) = nZ ± X (1)
It is preferable to calculate based on By calculating the number of caulking points in this way, it is possible to reduce noise, vibration, etc. that may occur in the rolling bearing 5.

  According to the third embodiment, the cylindrical portion 12a of the magnet holder 12 and the outer cylindrical portion 16a of the sensor housing 16 are circumferentially inserted into the locking groove 41 of the bearing inner ring 2 and the locking groove 42 of the bearing outer ring 3. Since it is fixed by caulking at equal intervals, the accuracy of mounting the magnet holder 12 and the sensor housing 16 can be improved. Further, by calculating the number of crimped portions of the cylindrical portion 12a and the outer cylindrical portion 16a by the above equation (1), it is possible to reduce noise, vibration, and the like that may occur in the rolling bearing 5.

  In the first to third embodiments, the case where the bearing inner ring 2 is a rotating side wheel and the bearing outer ring 3 is a fixed side ring has been described. However, the present invention is not limited to this. The present invention can also be applied to the case where the bearing outer ring 3 is fitted into the rotating shaft while the shaft is fixed to the housing or the like. In this case, the magnet holder 12 holding the ring magnet 11 may be fixed to the bearing outer ring 3 side, and the sensor housing 16 holding the magnetic sensor 15 may be fixed to the bearing inner ring 2 side.

Moreover, in the said 1st-3rd embodiment, although the case where the ring magnet 11 was comprised by connecting the eight magnet pieces 11a was demonstrated, it is not limited to this, The ring magnet 11 The number of magnetic poles can be set to an arbitrary number according to the usage state of the sensor-equipped rolling bearing 1.
Moreover, in the said 1st-3rd embodiment, although the case where this invention was applied to the radial rolling bearing was demonstrated, it is not limited to this, It can apply this invention also to a thrust rolling bearing. it can.

  In the first and second embodiments, the case where the magnetic sensor 15 is an analog type such as a Hall element has been described. However, the present invention is not limited to this, and the magnetic field of the ring magnet 11 is detected. Thus, a digital type magnetic sensor that directly outputs a pulse detection signal can be applied, and in this case, the signal processing circuit 20 can be omitted. Further, the magnetic sensitive sensor 15 is not limited to a Hall element, and other magnetic sensitive sensors can be applied. For example, when a giant magnetoresistive effect element (GMR element) is applied, the sensitivity of magnetic detection is increased, so that it is possible to detect more accurately even in the axial direction where the clearance inside the bearing is relatively large.

  DESCRIPTION OF SYMBOLS 1 ... Rolling bearing with a sensor, 2 ... Bearing inner ring, 3 ... Bearing outer ring, 4 ... Rolling body, 5 ... Rolling bearing, 11 ... Ring magnet, 12 ... Magnet holder, 12a ... Cylindrical part, 12b ... Circular plate part, 12c ... Flange part, 15 ... magnetic sensitive sensor, 16 ... sensor housing, 16a ... outer cylinder part, 16b ... annular plate part, 16c ... inner cylinder part, 17 ... substrate, 18 ... mold, 18a ... cylindrical part, 19 ... sensor Gap, 20 ... signal processing circuit, 21 ... signal line, 31 ... labyrinth, 31a to 31d ... gap, 41, 42 ... locking recess

Claims (5)

A rotating side wheel,
A fixed side wheel,
A rolling element interposed between the rotating side wheel and the fixed side;
A ring magnet held by a magnet holder fixed to the rotating side wheel;
A magnetic sensitive sensor held in a sensor housing fixed to the fixed side wheel and facing the ring magnet with a predetermined gap;
The magnet holder and the sensor housing are made of a magnetic material, and the magnet holder and the sensor housing are arranged so as to magnetically shield between the ring magnet and the magnetic sensitive sensor. bearing.   The magnet holder is disposed so as to cover a bearing space between the rotating side wheel and the fixed side wheel, and the sensor housing is formed in a U-shaped cross section so as to cover the magnet holder. A rolling bearing with a sensor according to claim 1.   3. The sensor-equipped rolling bearing according to claim 2, wherein the magnet holder includes at least an annular plate portion that covers the bearing space and a flange portion that contacts an outer diameter side of the ring magnet.   The rolling bearing with a sensor according to claim 1, wherein the magnetic sensor is fixed to the sensor housing by a mold part.   The said mold part has the cyclic | annular protrusion part extended in the other side vicinity on both sides of the said flange part and a ring magnet, The labyrinth was formed in the circumference | surroundings including the said predetermined space | gap of the said ring magnet. Rolling bearing with sensor as described.

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