JP2012026829A - Rotation detection device and bearing with rotation detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly versatile rotation detection device which is not affected by any use environment or the like for increasing the resolution of a pulse signal by a simple structure and a bearing with the rotation detection device.SOLUTION: A rotation detection device 1 comprises a magnetic encoder 2 and a magnetic sensor 3 for detecting the magnetic field of the magnetic encoder 2. The magnetic sensor 3 has a magnetic sensor circuit including a plurality of linearly aligned magnetic sensor elements 3a, and having a function for generating a two-phase sine wave-shaped signal by an arithmetic operation from the output of each magnetic sensor element 3a, and for detecting the phase in one magnetic pole of the magnetic encoder 2. An alignment direction A2 of the magnetic poles of the magnetic encoder 2 and an alignment direction A1 of the plurality of magnetic sensor elements 3a configuring the magnetic sensor circuit are relatively obliquely arranged.

Description

  The present invention relates to a rotation detection device and a bearing with a rotation detection device used for rotation detection, rotation angle detection, and linear movement detection of various devices.

With respect to the technical field of bearing elements, techniques for obtaining interpolated pulse signals using magnetic sensors arranged in a line are disclosed (Patent Documents 1 and 2).
A so-called optical encoder is disclosed, and an encoder with an absolute angle detection function is described (Patent Document 3).

JP-T-2001-518608 Special Table 2002-541485 Japanese Patent No. 4269246

It is difficult to obtain a high-resolution rotation pulse in a magnetic encoder.
When realizing high resolution with the sensor configuration described in Patent Document 1, the magnetic encoder magnetic pole width (N pole width or N pole width) that can be handled by the arrangement of sensor elements arranged in a line, that is, the length of the line sensor. S pole width) is limited. For example, for a sensor element array of about 4 mm, the magnetic encoder cannot be detected with a magnetic pole width of 1 mm or less, and high resolution of the pulse signal is limited.

On the other hand, when the resolution is increased by increasing the multiplication factor of the sensor element, the arithmetic circuit inside the sensor element is complicated and easily affected by the SN ratio, resulting in an increase in cost.
In the case of light detection as described in Patent Document 3, it is easy to achieve high resolution, but usage is limited because it cannot be used in a dust / oil environment.

  An object of the present invention is to provide a highly versatile rotation detector and a bearing with a rotation detector that can increase the resolution of a pulse signal with a simple structure and are not affected by the use environment.

  The rotation detection device of the present invention is a rotation detection device including a magnetic encoder and a magnetic sensor for detecting a magnetic field of the magnetic encoder, and the magnetic sensor includes a plurality of magnetic sensor elements arranged in a straight line, A magnetic sensor circuit having a function of detecting a phase in one magnetic pole of the magnetic encoder, wherein an alignment direction of magnetic poles of the magnetic encoder and an alignment direction of a plurality of magnetic sensor elements constituting the magnetic sensor circuit are It is characterized by being arranged diagonally.

According to this configuration, the plurality of magnetic sensor elements are arranged on a straight line. A plurality of magnetic sensor elements arranged on this straight line are referred to as “line sensors” in this specification. Of the magnetic sensors, only the portions of a plurality of magnetic sensor elements are referred to as “line sensor portions”. For example, the magnetic sensor circuit generates a two-phase sinusoidal signal from the output of each magnetic sensor element, thereby reducing the influence of distortion and noise of the magnetic field pattern and detecting the phase of the magnetic encoder with higher accuracy. obtain.
However, when a magnetic sensor including the line sensor is used, it is necessary to match the length of the line sensor and the length of one magnetic pole pair of the magnetic encoder to some extent. If these relationships do not match, the signal accuracy deteriorates. On the other hand, due to the configuration of the magnetic sensor, the signal accuracy cannot be improved if the magnetic pole width of each magnetic encoder is too small.

Therefore, in the rotation detection device of the present invention, the line sensor portion is arranged by relatively arranging the arrangement direction of the magnetic poles of the magnetic encoder and the arrangement direction of the plurality of magnetic sensor elements constituting the magnetic sensor circuit. Is apparently provided with one magnetic pole pair of the magnetic encoder, and the magnetic pole width of each magnetic encoder magnetic encoder can be reduced to a desired value or less.
For example, the magnetic pole width is 0.5 mm and the arrangement direction of the plurality of magnetic sensor elements is arranged at 60 degrees with respect to the arrangement direction of the magnetic encoder magnetic poles. Then, the value obtained by multiplying the length of the line sensor by cos 60 and the length of one magnetic pole pair of the magnetic encoder can be made apparently the same, and the magnetic pole width can be set to a desired value, that is, 1 mm or less. Thereby, the resolution of the pulse signal can be increased as compared with the conventional one. In addition, by changing the inclination angle formed by the magnetic pole arrangement direction and the arrangement direction of the plurality of magnetic sensor elements in various ways, it is possible to obtain an optimal resolution combination for the length of the line sensor. Detection with a magnetic encoder having various resolutions is possible using the element. In addition, because it is a magnetic encoder, the usage environment is not limited as in the case of light detection, and the phase of the magnetic encoder can be detected with high accuracy even in usage environments such as dusty and oily environments. obtain.

  The magnetic sensor circuit may be configured to detect and output a sin and cos two-phase signal output from the outputs of the magnetic sensor elements and multiply the position inside the magnetic pole. In this case, it is possible to achieve high resolution, which is the number of pulses obtained by multiplying the multiplication rate by the number of magnetic pole pairs of the magnetic encoder. Further, the magnetic field distribution of the magnetic encoder can be detected finely as a sinusoidal signal based on an analog voltage, not as an on / off signal.

  The magnetic pole pitch of one magnetic pole pair along the rotation direction of the magnetic encoder may be less than or equal to one half of the length of the plurality of magnetic sensor elements arranged on the straight line. By arranging the magnetic encoder magnetic pole arrangement direction and the magnetic sensor element arrangement directions constituting the magnetic sensor circuit relatively obliquely, the magnetic pole width of each magnetic encoder magnetic pole is less than a desired value. Therefore, the magnetic pole pitch of one magnetic pole pair (the length of one magnetic pole pair) is not limited according to the length of the line sensor. In other words, the phase of the magnetic encoder can be detected with high accuracy without degrading the signal accuracy without matching the magnetic pole pitch of one magnetic pole pair to the length of the line sensor.

  The boundary line between the N pole and the S pole in each magnetic pole pair of the magnetic encoder may be arranged obliquely with respect to the moving direction of the magnetic encoder. In this case, the arrangement direction of the plurality of magnetic sensor elements can be arranged in a direction orthogonal to the moving direction of the magnetic encoder. Therefore, the positioning of the line sensor can be easily positioned with respect to the magnetic encoder.

By arranging the entire magnetic sensor circuit obliquely with respect to the moving direction of the magnetic encoder, the magnetic pole arrangement direction of the magnetic encoder and the arrangement direction of a plurality of magnetic sensor elements constituting the magnetic sensor circuit are relatively Alternatively, it may be arranged obliquely.
By arranging the magnetic pole arrangement direction of the magnetic encoder and the entire magnetic sensor circuit obliquely with respect to the movement direction of the magnetic encoder, the magnetic encoder arrangement direction and the plurality of magnetic sensor circuits constituting the magnetic sensor circuit are arranged. The arrangement direction of the magnetic sensor elements may be arranged relatively obliquely. In this case, the degree of freedom for obtaining a combination of resolutions optimal for the length of the line sensor is increased. In addition, the dimension of the line sensor in the direction orthogonal to the moving direction of the magnetic encoder can be suppressed.

The plurality of magnetic sensor elements and magnetic sensor circuits may be integrated on a semiconductor chip. In this case, the resolution can be adjusted freely by changing the mounting angle of the semiconductor chip with respect to the magnetic encoder magnetic pole arrangement direction, and the plurality of magnetic sensor elements and magnetic sensor circuits can be made compact and handled. It can be simplified.
The magnetic encoder may be a rubber magnet mixed with ferrite magnetic powder or rare earth magnet powder, or a plastic magnet. When ferrite magnetic powder is used, it is more advantageous in terms of cost than using rare earth magnet powder. When using rare earth magnet powder, the magnetic flux density is higher than when using ferrite magnetic powder, so that a wide air gap between the magnetic sensor and the magnetic encoder can be secured. The degree of freedom increases.

The magnetic encoder may be a sintered magnet in which magnetic poles are alternately formed in the circumferential direction on a sintered body obtained by sintering a mixed powder of magnetic powder and non-magnetic powder.
The magnetic encoder may be formed in a ring shape.

  The magnetic encoder is a linear magnetic encoder extending linearly, and a combination of the linear magnetic encoder and the magnetic sensor circuit generates a two-phase sinusoidal signal from the output of each magnetic sensor element constituting the magnetic sensor circuit. It is good also as what detects by the calculation and the position in a magnetic pole. When performing such a linear motion type position detection, it is particularly suitable for use in detecting minute displacements. In that case, in addition to any one of the above magnetic encoders, a magnetic encoder formed by superposing a plurality of thin rare earth magnets Therefore, space can be saved.

  In the bearing with a rotation detection device of the present invention, the rotation detection device in which the magnetic encoder is formed in a ring shape is mounted on the bearing. In this case, since the bearing with the rotation detecting device can be incorporated into the bearing using device, the number of steps for assembling the rotation detecting device into the bearing using device separately from the bearing can be reduced. In addition, it is possible to reduce the size of the entire bearing equipment.

  The rotation detection device of the present invention is a rotation detection device including a magnetic encoder and a magnetic sensor for detecting a magnetic field of the magnetic encoder, and the magnetic sensor includes a plurality of magnetic sensor elements arranged in a straight line, A magnetic sensor circuit having a function of detecting a phase in one magnetic pole of the magnetic encoder, wherein an alignment direction of magnetic poles of the magnetic encoder and an alignment direction of a plurality of magnetic sensor elements constituting the magnetic sensor circuit are Therefore, the resolution of the pulse signal can be increased with a simple structure, and a highly versatile rotation detector that is not affected by the use environment or the like can be obtained.

It is an expanded view of the principal part of the radial type rotation detection apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing of the rotation detection apparatus. It is explanatory drawing which shows the example which comprised the magnetic sensor of the rotation detection apparatus with the line sensor. It is a front view of the principal part of the axial type rotation detection apparatus which concerns on other embodiment of this invention. It is sectional drawing of the rotation detection apparatus. (A) is an expanded view of the principal part of the radial type rotation detection apparatus which concerns on other embodiment of this invention, (B) is a front view of the principal part of an axial type rotation detection apparatus. (A) is an expanded view of the principal part of the rotation detection apparatus which concerns on further another embodiment of this invention, (B) is a front view of the principal part of an axial type rotation detection apparatus. (A) is an expanded view of the principal part of the rotation detection apparatus which concerns on further another embodiment of this invention, (B) is a front view of the principal part of an axial type rotation detection apparatus. It is sectional drawing which shows one Embodiment of the bearing with a rotation detection apparatus which mounted this rotation detection apparatus in the bearing. (A) is sectional drawing of the axial type rotation detection apparatus of a prior art example, (B) is a front view of the principal part of the rotation detection apparatus. (A) is sectional drawing of the radial type rotation detection apparatus of a prior art example, (B) is an expanded view of the principal part of the rotation detection apparatus.

A first embodiment of the present invention will be described with reference to FIGS. The rotation detection device according to the embodiment of the present invention is applied to rotation detection and rotation angle detection of various devices. First, a radial type rotation detection device will be described.
As shown in FIG. 2, the rotation detection device 1 includes an annular magnetic encoder 2 and a magnetic sensor 3 that detects the magnetic field of the magnetic encoder 2. The magnetic encoder 2 has a cylindrical cored bar 4 and an annular magnetic encoder track 5. The core metal 4 includes a core metal body 4a having a magnetic encoder track 5 on the outer peripheral surface, and a fitting portion 4c connected via a step 4b radially inward from one axial edge of the core metal body 4a. It becomes. The inner peripheral surface of the fitting portion 4c is attached to the outer peripheral surface 6a of the attachment target 6 by press fitting or the like, and the axis of the magnetic encoder 2 is provided concentrically with the axis L1 of the attachment target 6.

  The magnetic encoder 2 is composed of a rubber magnet mixed with ferrite magnetic powder or rare earth magnet powder, or a plastic magnet. When ferrite magnetic powder is used, it is more advantageous in terms of cost than using rare earth magnet powder. When the rare earth magnet powder is used, the magnetic flux density is higher than when ferrite magnetic powder is used, so that a wide air gap Gp between the magnetic sensor 3 and the magnetic encoder 2 can be secured. The degree of freedom of the mounting method 3 is increased. The magnetic encoder 2 may be a sintered magnet in which magnetic poles are alternately formed in the circumferential direction on a sintered body obtained by sintering a mixed powder of magnetic powder and nonmagnetic powder.

The magnetic sensor 3 is provided on a fixed member or the like so as to face the magnetic encoder track 5 in the radial direction, that is, in the radial direction via the gap Gp.
As shown in a developed view in FIG. 1, the magnetic encoder track 5 is a ring-shaped magnetic member in which a plurality of magnetic pole pairs are magnetized at an equal pitch in the circumferential direction. One magnetic pole pair refers to one set of a magnetic pole S and a magnetic pole N. In the magnetic encoder 2 of the radial type, a magnetic pole pair is magnetized on the outer peripheral surface of a ring-shaped magnetic encoder track 5.

  As shown in FIG. 3B, the magnetic sensor 3 includes a plurality of magnetic sensor elements 3a arranged in a straight line, that is, a line sensor, and 2 shown in FIG. 3C from the output of each magnetic sensor element 3a. A magnetic sensor circuit 7 having a function of detecting a phase in one magnetic pole of the magnetic encoder 2 by generating a sinusoidal signal of a phase by calculation. The plurality of magnetic sensor elements 3a and the magnetic sensor circuit 7 are integrated on, for example, a semiconductor chip. The magnetic sensor circuit 7 includes adder circuits 8, 9, 10, 11 and an inverter 12, which will be described later. The arrangement direction A1 of the plurality of magnetic sensor elements 3a constituting the magnetic sensor circuit 7 is relatively obliquely arranged with respect to the arrangement direction A2 of the magnetic poles of the magnetic encoder 2.

In the example of FIG. 1, the arrangement direction A2 of the magnetic poles and the arrangement direction A1 of the plurality of magnetic sensor elements 3a are arranged to form an inclination angle of an angle α (in this example, α = 60 degrees). Thus, by arranging the line sensor obliquely with respect to the magnetic pole arrangement direction A2, one magnetic pole pair of the magnetic encoder 2 is apparently given to the line sensor portion indicated by hatching in FIG. The magnetic pole width δ of each magnetic pole can be set to a desired value or less (for example, 1 mm or less).
For example, the magnetic pole width δ is set to 0.5 mm, and the arrangement direction A1 of the plurality of magnetic sensor elements 3a is arranged at 60 degrees with respect to the arrangement direction A2 of the magnetic poles of the magnetic encoder 2. Then, the value obtained by multiplying the length La of the line sensor by cos 60 and the length Lb of one magnetic pole pair of the magnetic encoder 2 appear to be the same. As a result, the resolution of the pulse signal is as follows.

The number of magnetic pole pairs of the magnetic encoder 2 is obtained as 156 pole pairs from the outer diameter D (D = 50 mm) of the outer peripheral surface of the magnetic encoder track 5 and the magnetic pole width δ (δ = 0.5 mm). This 156 pole pair includes 156 N poles and 156 S poles.
Here, the magnetic pole width δ is obtained by dividing the value obtained by multiplying the outer diameter dimension D by the circumferential ratio π by the value obtained by multiplying the number of magnetic pole pairs by two. δ = D · π / (2 · number of magnetic pole pairs) = 50 · π / (2 · 156) = 0.503 mm
The multiplication factor of the magnetic sensor element 3a is set to 40 times. The multiplication factor of 40 means that a pulse signal of 40 times can be obtained for one magnetic encoder magnetic pole pair.
Then, the maximum resolution of 6240 pulses (AB phases) obtained by multiplying the number of magnetic pole pairs 156 by the multiplication factor 40 can be achieved. This 6240 pulse corresponds to a resolution of 0.058 degrees.

In the conventional example shown in FIGS. 10 and 11 as a comparative example, when the magnetic sensor element 3a having a multiplication factor of 40 is combined with the magnetic encoder track 5 having the outer diameter D (D = 50 mm),
The number of magnetic pole pairs of the magnetic encoder 2 is determined to be 78 pole pairs (N pole: 78 pieces, S pole: 78 pieces). Here, the magnetic pole width δ = 50 · π / (2.78) = 1.01 mm> 1 mm.
-Multiplication rate of magnetic sensor element 3a: 40 times In this case, in the conventional example, the maximum resolution of 3120 pulses (AB phases) obtained by multiplying the magnetic pole pair number 78 by the multiplication factor 40 can be achieved. This 3120 pulse corresponds to a resolution of 0.115 degrees.

  FIG. 3A shows a section of one magnetic pole pair in a magnetic encoder converted into a magnetic field strength and shown in a waveform diagram. In this case, the line sensor portion obtained by multiplying the length of the line sensor by cos α is the N pole in the phase interval of 0 ° to 180 ° and the phase interval of 180 ° to 360 ° in one magnetic pole pair in FIG. Are arranged in association with the S pole section. With such an arrangement, the signal S1 obtained by adding the detection signals of the line sensor corresponding to the phase interval of 0 ° to 90 ° by the adding circuit 8 and the detection signal of the line sensor corresponding to the phase interval of 90 ° to 180 °. Is added by the adder circuit 9 and is added by another adder circuit 10 to obtain a sin signal corresponding to the magnetic field signal as shown in FIG. The signal S1 and the signal S2 via the inverter 12 are added by another adding circuit 11 to obtain a cos signal corresponding to the magnetic field signal as shown in FIG. The position within the magnetic pole range is detected from the two-phase output signal thus obtained. The detection signal of the line sensor corresponding to the phase interval of 180 degrees to 360 degrees is also added by a similar adder circuit to obtain a sin signal and a cos signal. From these two-phase output signals, the position within the magnetic pole range is obtained. Is detected.

According to the rotation detection device 1 described above, the magnetic sensor circuit 7 generates a two-phase sinusoidal signal from the output of each magnetic sensor element 3a, so that the effects of distortion of the magnetic field pattern and noise are reduced and higher. The phase of the magnetic encoder 2 can be detected with accuracy.
In particular, in the rotation detection device 1, the magnetic sensor 2 has a magnetic encoder 2 in which the magnetic pole arrangement direction A2 and the magnetic sensor elements 3a are arranged in a relatively oblique direction, so that the line sensor portion has a magnetic encoder. Two magnetic pole pairs are apparently provided, and the magnetic pole width δ of each magnetic pole of the magnetic encoder 2 can be reduced to a desired value of 1 mm or less. Thereby, the resolution of the pulse signal can be increased as compared with the conventional one. In addition, since the inclination angle α formed by the magnetic pole arrangement direction A2 and the magnetic sensor element 3a arrangement direction A1 can be variously changed, an optimum combination of resolutions for the line sensor length La can be obtained. The magnetic encoder 2 having various resolutions can be detected using the same magnetic sensor element 3a. In addition, since it is a magnetic encoder, the usage environment is not limited as in the case of light detection, and the phase of the magnetic encoder 2 can be detected with high accuracy even in a usage environment such as dust and oil. Can do. In this way, the resolution of the pulse signal can be increased with a simple structure, and a highly versatile rotation detector 1 that is not affected by the use environment or the like can be obtained.

The magnetic sensor circuit 7 is configured to generate two-phase signal outputs of sin and cos from the output of each magnetic sensor element 3a by calculation and multiply and detect the position inside the magnetic pole. The resolution can be increased to the number of pulses multiplied by the number of magnetic pole pairs of the encoder 2. Further, the magnetic field distribution of the magnetic encoder 2 can be finely detected as a sinusoidal signal based on an analog voltage, not as an on / off signal.
Since the plurality of magnetic sensor elements 3a and the magnetic sensor circuit 7 are integrated on the semiconductor chip, the resolution can be freely set by changing the mounting angle of the semiconductor chip with respect to the magnetic pole arrangement direction A2 of the magnetic encoder 2. In addition, the plurality of magnetic sensor elements 3a and the magnetic sensor circuit 7 can be made compact and easy to handle.

Another embodiment of the present invention will be described. In the following description, the same reference numerals are given to the portions corresponding to the matters described in the preceding forms in each embodiment, and the overlapping description is omitted.
The rotation detection device shown in FIGS. 4 and 5 is an axial type rotation detection device 1A in place of the radial type rotation detection device described above. As shown in FIG. 5, an annular cored bar 4A of the rotation detecting device 1A is formed in an L-shaped cross section with a standing plate portion 4Aa and a cylindrical portion 4Ab, and a magnetic encoder track 5 is formed on the outer surface of the standing plate portion 4Aa. It is provided in an annular shape, and the inner peripheral surface of the cylindrical portion 4Ab is attached to the outer peripheral surface 6a of the attachment target 6 by press fitting or the like. The magnetic sensor 3 is provided on a fixed member or the like so as to face the magnetic encoder track 5 in the axial direction, that is, the axial direction via the gap Gp.

  As shown in FIG. 4, the magnetic encoder 2 is arranged so that the magnetic pole 2 alignment direction A2 and the magnetic sensor elements 3a alignment direction A1 form an inclination angle α (in this example, α = 60 degrees). Is done. Thus, also in the axial type rotation detection device 1A, the arrangement direction A2 of the magnetic poles of the magnetic encoder 2 and the arrangement direction A1 of the plurality of magnetic sensor elements 3a are relatively obliquely arranged, so that FIG. The length Lb of one magnetic pole pair of the magnetic encoder 2 is apparently given to the line sensor portion indicated by hatching, and the magnetic pole width δ of each magnetic pole of the magnetic encoder 2 can be reduced to a desired 1 mm or less. Thereby, the resolution of the pulse signal can be increased as compared with the conventional one. Further, since it is a magnetic encoder, the use environment is not limited as in the case of light detection, and the phase of the magnetic encoder 2 can be adjusted with high accuracy even in the use environment such as dust / oil environment. Can be detected. Thus, the resolution of the pulse signal can be increased with a simple structure, and a highly versatile rotation detector that is not affected by the use environment or the like can be obtained.

  As shown in FIG. 6A, in the radial type rotation detection device 1, the alignment direction A1 of the plurality of magnetic sensor elements 3a is the axial direction, and the boundary between the N pole and the S pole in each magnetic pole pair of the magnetic encoder 2 The line Lc may be disposed obliquely with respect to the moving direction A3 of the magnetic encoder 2. That is, the magnetic pattern of the magnetic encoder 2 is inclined and the line sensor portion indicated by hatching in FIG. 6A is arranged in a direction perpendicular to the moving direction A3 of the magnetic encoder 2. In this case, the positioning of the line sensor can be easily positioned with respect to the magnetic encoder 2. As shown in FIG. 6B, in the axial type rotation detection device 1A, the alignment direction of the plurality of magnetic sensor elements 3a is the radial direction, and the boundary line between the N pole and the S pole in each magnetic pole pair of the magnetic encoder 2 Lc may be disposed obliquely with respect to the moving direction A3 of the magnetic encoder 2. Also in this case, the positioning of the line sensor can be easily positioned with respect to the magnetic encoder 2.

  As shown in FIG. 7A, in the radial type rotation detection device 1, the magnetic pattern of the magnetic encoder 2 is inclined, and the arrangement direction A1 of the plurality of magnetic sensor elements 3a is inclined with respect to the arrangement direction A2 of the magnetic poles. Is arranged. That is, the arrangement direction A2 of the magnetic poles of the magnetic encoder 2 and the entire magnetic sensor circuit are arranged obliquely with respect to the moving direction of the magnetic encoder 2, respectively. In this case, the degree of freedom for obtaining a combination of resolutions optimal for the length La of the line sensor is higher than that of the rotation detection device of FIGS. Further, in the configuration of FIG. 6, the dimension of the line sensor in the direction orthogonal to the moving direction of the magnetic encoder 2 is increased, but according to the configuration of FIG. 7, the line sensor is orthogonal to the moving direction of the magnetic encoder 2. It becomes possible to suppress the dimension of the direction to do. As shown in FIG. 7B, in the axial type rotation detection device 1A, the magnetic pole 2 alignment direction A2 and the entire magnetic sensor circuit are arranged obliquely with respect to the moving direction of the magnetic encoder 2, respectively. You may do it.

  As shown in FIG. 8A, in the radial type rotation detecting device 1, only the line sensor portion indicated by hatching in the magnetic sensor 3 may be disposed obliquely with respect to the magnetic pole arrangement direction A2. In this case, the case 3 b that houses the line sensor portion of the magnetic sensor 3 is provided in a rectangular shape, and both side portions 3 ba and 3 ba of the case 3 b can be arranged in parallel to the moving direction of the magnetic encoder 2. Therefore, the magnetic sensor 3 can be easily arranged with respect to the magnetic encoder 2. As shown in FIG. 8B, in the axial type rotation detection device 1A, only the line sensor portion of the magnetic sensor 3 may be arranged obliquely with respect to the magnetic pole arrangement direction A2.

FIG. 9 is a cross-sectional view showing an embodiment of a bearing with a rotation detection device in which any one of the radial type rotation detection devices 1 is mounted on a bearing BR.
As shown in the figure, for example, a deep groove ball bearing is applied to the rolling bearing BR, and an inner ring 13, an outer ring 14, a plurality of rolling elements 15, and a cage (not shown) that holds the rolling elements 15. And a seal member 16. As the rolling bearing BR, various rolling bearings such as an angular ball bearing, a cylindrical roller bearing, a tapered roller bearing, and a self-aligning roller bearing can be applied. Further, in this example, the core metal 4 of the magnetic encoder 2 is press-fitted and fitted to the outer peripheral surface on the right side of FIG. 9 where the seal member 16 is not provided in the inner ring 13 that is the rotation side raceway ring. The inner peripheral surface 17a of the sensor core 17 for holding the magnetic sensor 3 is press-fitted and fitted to the right inner peripheral surface. A resin member 18 made of a non-magnetic material is provided inside the annular ring 17 of the sensor metal core, and the magnetic sensor 3 is embedded in the resin member 18.

  When the rotation detection device 1 including the magnetic encoder 2 and the magnetic sensor 3 is mounted on the bearing BR in this way, the bearing BR with the rotation detection device can be incorporated into the bearing use device. Therefore, the rotation detection device is used separately from the bearing. Can reduce the number of man-hours to assemble In addition, it is possible to reduce the size of the entire bearing equipment. It is also possible to mount one of the axial type rotation detection devices 1A on the bearing BR.

  A magnetic encoder may be configured by using a thin sintered magnet and alternately arranging in the circumferential direction so that the direction of the magnetic field generated in the exposed cross section is alternated. In this case, since a strong magnetic field is obtained, a magnetic encoder with a fine pitch can be formed with high accuracy.

  One of the magnetic encoders is a linear magnetic encoder extending linearly, and a combination of the linear magnetic encoder and the magnetic sensor circuit is used to output a two-phase sinusoidal signal from the output of each magnetic sensor element constituting the magnetic sensor circuit. May be generated by calculation to detect the position in the magnetic pole. When performing such a linear motion type position detection, it is particularly suitable for use in detecting minute displacements. In that case, in addition to any one of the above magnetic encoders, a magnetic encoder formed by superposing a plurality of thin rare earth magnets Therefore, space can be saved.

DESCRIPTION OF SYMBOLS 1,1A ... Rotation detection apparatus 2 ... Magnetic encoder 3 ... Magnetic sensor 3a ... Magnetic sensor element 7 ... Magnetic sensor circuit

Claims (12)

A rotation detection device comprising a magnetic encoder and a magnetic sensor for detecting a magnetic field of the magnetic encoder,
The magnetic sensor includes a plurality of magnetic sensor elements arranged in a straight line, and includes a magnetic sensor circuit having a function of detecting a phase within one magnetic pole of a magnetic encoder,
A rotation detection device, wherein the magnetic encoder magnetic pole arrangement direction and the magnetic sensor element arrangement direction constituting the magnetic sensor circuit are arranged relatively obliquely.   2. The rotation detection device according to claim 1, wherein the magnetic sensor circuit is configured to generate two-phase signal outputs of sin and cos from the outputs of the magnetic sensor elements by calculation and to multiply and detect the position inside the magnetic pole. .   3. The rotation detection device according to claim 1, wherein the magnetic pole pitch of one magnetic pole pair along the rotation direction of the magnetic encoder is equal to or less than half of the length of the plurality of magnetic sensor elements arranged on the straight line. .   4. The rotation detection device according to claim 1, wherein a boundary line between an N pole and an S pole in each magnetic pole pair of the magnetic encoder is arranged obliquely with respect to a moving direction of the magnetic encoder.   4. The magnetic sensor circuit according to claim 1, wherein the entire magnetic sensor circuit is arranged obliquely with respect to the moving direction of the magnetic encoder, whereby the magnetic pole arrangement direction of the magnetic encoder and the magnetic sensor circuit are A rotation detection device that arranges a plurality of magnetic sensor elements that are arranged relatively obliquely with respect to each other.   4. The magnetic encoder according to claim 1, wherein an arrangement direction of magnetic poles of the magnetic encoder and an entire magnetic sensor circuit are respectively arranged obliquely with respect to a moving direction of the magnetic encoder. Rotation detecting device in which the magnetic pole arrangement direction and the magnetic sensor element constituting the magnetic sensor circuit are arranged relatively obliquely.   7. The rotation detecting device according to claim 1, wherein the plurality of magnetic sensor elements and the magnetic sensor circuit are integrated on a semiconductor chip.   8. The rotation detecting device according to claim 1, wherein the magnetic encoder is formed of a rubber magnet or a plastic magnet mixed with ferrite magnetic powder or rare earth magnet powder.   9. The magnetic encoder according to claim 1, wherein the magnetic encoder forms magnetic poles alternately in a circumferential direction on a sintered body obtained by sintering a mixed powder of magnetic powder and nonmagnetic powder. Rotation detector that is a sintered magnet.   10. The rotation detection device according to claim 1, wherein the magnetic encoder is formed in a ring shape.   10. The magnetic sensor circuit according to claim 1, wherein the magnetic encoder is a linear magnetic encoder extending linearly, and the linear magnetic encoder and the magnetic sensor circuit are combined. A rotation detector that detects a position in a magnetic pole by generating a two-phase sinusoidal signal from the output of each magnetic sensor element by calculation.   A bearing with a rotation detection device, wherein the rotation detection device according to claim 10 is mounted on the bearing.

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