JP2003344101A - Rotating condition detector and rotator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotating condition detector having a simple structure capable of detecting the rotation speed, the rotating direction, and the absolute angle of a rotary member at the same time using a single sensor, and to provide a rotator having this rotation detector. <P>SOLUTION: The rotating condition detector has an encoder 10 composed of a single array of a plurality of magnetizing regions 12, 13 mounted on a rotary member 2 rotating, relative to a stationary member 1; and a sensor 20 facing the encoder 10 and mounted on the stationary member 1 for detecting the magnetic forces of the plurality of magnetizing regions 12, 13 of the encoder 10. The plurality of magnetizing regions 12, 13 have mutually different flux densities. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotational state detecting device for simultaneously detecting the rotational speed, the rotational direction and the rotational angle of a rolling device such as a bearing, and a bearing and a linear drive device equipped with this rotational state detecting device. Related to the rolling device.

[0002]

2. Description of the Related Art Generally, a rotation state detecting device is used to detect a rotation speed, a rotation direction, or a rotation angle of a rotating body such as a bearing. The rotation state detecting device includes a rotation sensor provided outside the rotating body and an object to be detected which is periodically arranged on the surface of the rotating body. The rotation sensor calculates the rotation speed, the rotation direction, or the rotation angle of the rotating body based on the detection cycle of the detected object and the known arrangement cycle of the detected object.

Japanese Patent Laid-Open No. 9-42994 discloses a slewing bearing having a slewing angle detector. This turning angle detector is composed of a scale and a sensor attached to each of an inner ring and an outer ring, which are race rings. The scale has north and south poles arranged alternately along the circumferential direction of the axis.
The sensor detects the magnetic force of the N pole and the S pole to detect a pulse signal, and counts the number of pulse signals. The signal conversion means converts the pulse signal into angle data according to the number of pulse signals and displays the angle data.

Japanese Patent Laid-Open No. 7-218239 discloses a grid pattern provided on a rotating ring of a bearing, a plurality of LEDs provided so as to face the grid pattern, and light emitted from a light source and changed by the pattern. Multiple PDs
And a bearing with a rotation angle detector. Light emitted from the plurality of LEDs forms light spots on the grid pattern, respectively. In the light spot, the intensity of reflected light periodically changes due to the dark portion and the light portion of the lattice pattern. Multiple PDs observe the changes in these reflected light intensities,
Calculate the rotation angle of the shaft according to the observation result.

Japanese Patent Laid-Open No. 7-218248 discloses a contact type rotation angle detecting device. This rotation angle detecting device includes an insulator layer provided on the end surface of the outer ring, a conductor pattern provided on the insulator layer, and a contactor provided on the inner ring and facing the conductor pattern. The contactor alternately contacts the conductor pattern and the insulator as the rotor rotates. The conductor pattern is short-circuited and becomes conductive due to contact with the contact. The rotation angle detection device detects the absolute angle of the rotating body by using the presence or absence of conduction between the conductor pattern and the contact.

However, the slewing bearing with a slewing angle detector disclosed in Japanese Unexamined Patent Publication No. 9-42994 can detect a rotation speed and a rotation angle when a single sensor is used, but simultaneously detects a rotation direction. Is impossible. Therefore, in order to detect the rotation speed, the rotation angle, and the rotation direction at the same time, a separate sensor must be provided. The additional sensor requires a mounting space for the sensor in the bearing, which makes it difficult to make the bearing compact. Further, since the two sensors are provided, the assembling property of the bearing is deteriorated and the cost is increased.

The bearing disclosed in JP-A-7-218239 is premised on the use of a plurality of sensors. Therefore, it is necessary to provide a mounting space for a plurality of sensors in the bearing, which makes it difficult to make the bearing compact. Further, the installation of a plurality of sensors deteriorates the assembling property of the bearing, which leads to an increase in manufacturing cost. Further, since the rotating body disclosed in JP-A-7-218248 must be formed on a special conductive pattern insulating layer,
Manufacturing costs are expected to increase.

On the other hand, Japanese Patent Laid-Open No. 2000-346673 discloses a rotation detecting device which overcomes the above problems. The present rotation detection device includes a magnet arranged on the circumference of the rotating body, and a single magnetic sensor arranged near the rotating body to detect a magnetic flux formed by the magnet. A plurality of pairs of N-pole, S-pole and no pole are sequentially provided on the rotating body, and the magnetic sensor has N-pole,
The rotation speed of the rotating body is detected by detecting the magnetic force without the S pole and without the pole. In addition, the magnetic sensor uses the magnetic pole detection order ("N pole-S pole-no pole" or "No pole-S pole-N".
The direction of rotation of the rotating body is measured based on the “pole”. Since this rotation speed detecting device can simultaneously measure the rotation speed and the rotation direction of the rotating body by using a single magnetic sensor, it is not necessary to provide another sensor, which is advantageous for downsizing the bearing.

The information on the rotation angle obtained from the pulse by the conventional rotation state detecting device is the relative rotation angle based on the angle before the start of rotation. Therefore, the absolute angle is calculated from the obtained relative rotation angle in consideration of the reference angle.

[0010]

However, it is conceivable that the angle information at the start of rotation may be lost due to a failure or replacement of the memory storing the angle before the start of rotation. In this case, there is a problem that the above-described device cannot calculate the absolute angle unless the reference angle is reset.

The present invention has been made in view of the above problems, and has a simple structure capable of simultaneously detecting the rotation speed, the rotation direction, and the absolute angle of a rotating body using a single sensor. An object of the present invention is to provide a device and a rolling device equipped with this rotation state detecting device.

[0012]

According to a first aspect of the present invention, there is provided a rotation state detecting device which comprises a plurality of magnetized regions which are attached to a rotating member which rotates with respect to a stationary member and which are arranged in a line. An encoder and a sensor that is attached to the stationary member, faces the encoder, and detects magnetic forces of the plurality of magnetized regions of the encoder,
The plurality of magnetized regions have different magnetic flux densities from each other.

According to the rotation state detecting device of the first aspect, the plurality of magnetized regions forming the encoder have different magnetic flux densities. Therefore, the rotational speed of the rotating member can be detected by detecting the peak using a single sensor. Further, by grasping the arrangement pattern of the magnetized regions having different magnetic flux densities in advance, it becomes possible to simultaneously detect the rotation direction and the absolute angle of the rotating member using a single sensor. This makes it possible to save space on the stationary member by using a simpler structure than the conventional one. Furthermore, since it is not necessary to provide an extra sensor, it is possible to detect the rotating member at low cost.

According to a second aspect of the present invention, the rotational state detecting device is characterized in that a plurality of magnetized regions of the encoder are constituted by a plurality of N poles and S poles arranged alternately.

According to the rotation state detecting device of the second aspect, since a plurality of N poles and S poles having different magnetic flux densities are alternately arranged, it is possible to emphasize the difference between peaks, which is high. It becomes possible to detect the absolute angle with the angular resolution.

According to a third aspect of the present invention, the rotational state detecting device is characterized in that the plurality of magnetized regions of the encoder are composed of N poles or S poles.

According to the rotation state detecting device of the third aspect, since the sensor facing surface of the encoder is composed of only the N pole or the S pole, the change in the detected value becomes a stepwise increase and the error is small. It becomes possible to perform the measurement.

According to the rotation state detecting device of the fourth and fifth aspects, the encoder faces the sensor in the axial direction or the radial direction of the rotating member. Therefore, a flexible design is possible according to the positional relationship between the rotating member and the stationary member, the shape, etc., and the versatility is high.

According to a sixth aspect of the present invention, the plurality of magnetized regions are arranged such that the magnetic flux density is gradually increased or gradually decreased. Since the detected value changes regularly as the magnetic flux density gradually increases or decreases,
The detection data can be easily processed.

According to the seventh aspect of the present invention, there is further provided a temperature measuring section for measuring the temperature of the sensor or encoder or the peripheral members thereof. Therefore, the detected value can be corrected according to the change in the magnetic flux density in the magnetized region due to the change in temperature. Therefore, it is possible to perform a more accurate measurement.

According to the rotation state detecting device of the eighth aspect, a seal member for sealing the encoder and the sensor is further provided. Therefore, it is possible to cut off the encoder and the sensor from the outside world to minimize the influence of disturbance. Therefore, the measurement accuracy is improved.

According to a ninth aspect of the present invention, there is provided a rolling device including a stationary member, a rotating member which rotates with respect to the stationary member, and a plurality of magnetizing members which are attached to the rotating member and arranged in a line. An encoder configured of a region, and a sensor that is attached to the stationary member, faces the encoder, and detects the magnetic forces of the plurality of magnetized regions of the encoder, and the plurality of magnetized regions, The magnetic flux density is different from each other.

The rolling device according to claims 9 to 16 of the present invention is one in which the rotation state detecting device according to claims 1 to 8 is incorporated into a general rolling device. In the rolling device incorporating the rotation state detecting device according to any one of claims 1 to 8, the plurality of magnetized regions forming the encoder have different magnetic flux densities from each other. Therefore, the rotational speed of the rotating member can be detected by detecting the peak using a single sensor. Further, by grasping the arrangement pattern of the magnetized regions having different magnetic flux densities in advance, it becomes possible to simultaneously detect the rotation direction and the absolute angle of the rotating member using a single sensor. This makes it possible to save space on the stationary member by using a simpler structure than the conventional one. Furthermore, since it is not necessary to provide an extra sensor, it is possible to detect the rotating member at low cost.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, first to fifth embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. Figure 1
FIG. 3 shows a deep groove ball bearing as a rolling device in which the rotation detecting device according to the first embodiment of the present invention is incorporated. The deep groove ball bearing has an outer ring 3, an inner ring 4, a plurality of balls 7 as rolling elements, a seal ring 8 and a cage 9.

The outer ring 3 is fixed to the inner peripheral surface 1a of the housing 1 which is a stationary member. The outer ring 3 is manufactured by forging a metal material such as carbon steel. The outer ring 3 has an outer ring raceway 5 for guiding the balls 7 on its inner peripheral surface.

Like the outer ring 3, the inner ring 4 is manufactured by forging a metal material such as carbon steel. The inner ring 4 is fitted onto the outer peripheral surface 2a of the shaft 2, which is a rotating member. Inner ring 4
Corresponds to the outer ring raceway 5 of the outer ring 3 and has an outer ring raceway 6 for guiding the balls 7 on the outer peripheral surface. The inner ring 4 rotates integrally with the shaft 2 as the shaft 2 rotates.

The ball 7 is composed of the outer ring raceway 5 of the outer ring 3 and the inner ring 4.
Are arranged in a line between the inner ring track 6 and the inner ring track 6. Ball 7
Follows the rotation of the inner ring 4 accompanying the rotation of the shaft 2 and the outer ring raceway 5
And rolling along the inner ring track 6.

The seal ring 8 closes and seals the openings at both ends of the space for accommodating the balls 7 between the outer ring 3 and the inner ring 4. The seal ring 8 prevents dust, moisture, foreign matter, and the like from entering the ball storage space from the outside, and prevents the lubricant from flowing out from the ball storage space. The seal rings 8 are fixed by fixing portions 3b formed on the inner peripheral surface of the outer ring 3, respectively.

The cage 9 rotatably holds the ball 7 between the outer ring raceway 5 and the inner ring raceway 6. As the cage 9, a punched cage of steel plate, a machined cage or the like can be used.

An annular encoder holding member 11 is provided upright on the outer peripheral surface 2a of the shaft 2. The encoder holding member 11 extends from the outer peripheral surface 2a of the shaft 2 in the direction of the housing 1, that is, in the outer diameter direction of the shaft 2. The encoder 10 is arranged on the axial side surface of the encoder holding member 11 in the axial direction.

On the other hand, on the inner peripheral surface 1a of the housing 1,
The sensor holding member 21 is provided upright. The sensor holding member 21 extends from the inner peripheral surface 1 a of the housing 1 in the direction of the shaft 2, that is, in the inner diameter direction of the housing 1. A single sensor 20 is arranged on the axial side surface of the sensor holding member 21. The sensor 20 faces the encoder 10 in the axial direction.

FIG. 2 is a perspective view showing the encoder 10, and FIG. 3 is a partially enlarged view thereof. Encoder 10
Has an annular shape whose radial width is larger than its axial width. The encoder 10 includes a plurality of north poles 12 and south poles 1.
It is formed by alternately arranging 3 in a circular shape at equal intervals. The plurality of N poles 12 and S poles 13 are magnetized regions having different magnetic flux densities.

The magnetized area forming the encoder 10 has a reference magnetized area having a certain minimum magnetic flux density. Then, each magnetized region is provided with the sensor 2 with the reference magnetized region as a reference.
The magnetic flux density is given so that the magnetic flux density becomes larger from the adjacent magnetized region in the clockwise direction when viewed from 0. In detail,
In this embodiment, the magnetic flux density of each magnetized region is given as follows.

[0035]

[Formula 1] A (k) = k · Aref A (k): Magnetic flux density of k adjacent magnetized regions clockwise from the reference magnetized region Aref: Magnetic flux density of the reference magnetized region, that is, reference magnetized region The magnetic flux density of the magnetized regions that are k adjacent to the magnetic region is k times the magnetic flux density of the reference magnetized region.
Next to the magnetized area having the maximum magnetic flux density, the reference magnetized area having the minimum magnetic flux density is arranged.

The encoder material is, for example, an alnico magnet, a ferrite magnet, a samarium / cobalt magnet, a neodymium / iron / boron magnet, or a bond magnet formed by mixing and molding plastics using various magnet powders. Can be used. Since the magnetic flux density of each magnetized region needs to be different, it is preferable to use a bond magnet whose magnetic flux density can be easily changed. Here, a bond magnet made of plastic containing ferrite powder is used. The magnetic force of the magnet changes depending on the temperature. Therefore, it is necessary to determine the magnetization intensity so that a certain magnetization region does not become the same as the peaks of other magnetization regions within the operating temperature condition.

The N poles 12 and S arranged in this way
The pole 13 forms a magnetic field having an intensity around the pole 13 according to the polarity and magnetic flux density of each. Therefore, a magnetic field corresponding to the intensity of the magnetic flux density of the N pole 12 and the S pole 13 is formed around the encoder 10. The position (arrangement angle) of the reference magnetized area of the encoder 10 is stored in a control circuit (not shown) as a reference of the absolute angle of the axis.

The sensor 20 is a magnetic sensor for detecting the magnetic field formed by the encoder 10. The sensor 20
It is arranged close to the surface of the encoder 10 and can sense the magnetic field formed by each magnetized region. As the sensor 20, a sensor that can detect a magnetic field, such as a Hall element or a coil, can be used. Here, a case where a Hall element is used will be described as an example. The Hall element is an element that generates a current according to the intensity and direction of the magnetic flux that crosses the Hall element.

The encoder 10 rotates as the shaft 2 rotates. The sensor 20 supplies a current value corresponding to the strength and direction of the magnetic flux formed by the N pole 12 or the S pole 13 located at a position facing the sensor 20 to a control circuit (not shown) through the cable 22.
Output via.

FIG. 4 is a graph showing the output signal detected by the sensor 20. In FIG. 4, the vertical axis represents the intensity of the output signal and the horizontal axis represents time. The magnitude of the output signal is
Proportional to the strength of the magnetic flux, the sign of the output signal is determined by the direction of the magnetic flux. Here, the pulse at the leftmost end in FIG. 4 is a pulse due to the magnetic flux formed by the reference magnetized region.
It can be seen from FIG. 4 that the absolute value of the intensity of the pulse peak increases with the passage of time. Therefore, in the case of FIG. 4, the control circuit determines that the shaft 2 is rotating in the direction in which the strength of the north pole 12 or the south pole 13 is increasing, that is, counterclockwise as viewed from the sensor 20. Then, the control circuit counts the number of peaks detected per unit time, and calculates the rotation speed based on the count number and the arrangement interval of the magnetized regions.

Further, the control circuit determines the absolute angle of the axis based on the intensity of the peak. When the output of the sensor detects a peak (point A or C in FIG. 4), the control circuit
It is determined that the magnetized area corresponding to the detected output faces the sensor 20. Then, the control circuit determines that there is an axis at the absolute angle corresponding to the detected magnetized area.
If the sensor output has a value at point B between the peaks, the absolute angle at point B is calculated from the ratio of the intensity at point A, which is the immediately preceding peak, and the difference in intensity between points A and B. To calculate. Specifically, the angle at point B is calculated by the following formula.

[0042]

[Formula 2] θ (B) = θ (A) + 180b / a · n θ (A): Absolute angle at point A θ (B): Absolute angle at point B a: Output intensity at point A b: Difference between output intensity at point A and output intensity at point B n: total number of magnetized areas arranged in the encoder

As described above, according to this embodiment, the encoder 10 and the sensor 20 are arranged so as to face each other in the axial direction. The encoder 10 includes a plurality of N poles 12 and S poles 1 arranged so that the magnetic flux density gradually increases.
It consists of 3. Therefore, it is possible to simultaneously detect the rotation speed, the rotation direction, and the rotation angle of the shaft 2 using the single sensor 20.

Therefore, since it is possible to detect the rotation speed, the rotation direction, and the rotation angle of the shaft with a simple structure, the number of parts can be reduced and the cost of parts can be reduced. . Furthermore, since the reduction in the number of parts improves the assembling property, the assembling cost can also be reduced.

Further, since the number of sensors is only one, the space of the bearing portion can be saved, and the overall design can be made more compact. Further, the reduction in the number of sensors also leads to a reduction in the weight of the bearing, and when used in an automobile or the like, it also contributes to an improvement in fuel consumption.

In this embodiment, the magnetic flux density in the magnetized region is gradually increased. However, a plurality of magnetized region groups whose magnetic flux density is gradually increased are prepared,
These may be arranged in a line. in this case,
The absolute angle of the magnetic flux can be uniquely obtained by counting the number of times the sensor has detected the magnetic flux in the reference magnetized region included in each magnetized region group. Further, in the plurality of magnetized area groups, only the strength of the reference magnetized area may be different from each other. In this case, the absolute angle can be detected by using the intensity of the reference magnetized region detected immediately before as a reference. The same effect can be obtained even if the magnetic flux density in the magnetized region is arranged so as to gradually decrease.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIGS. Here, the same members as those described in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 5 is a partially enlarged view of the encoder 15 used in the rotation detecting device according to the second embodiment of the present invention. In the present embodiment, the encoder 15 is arranged so as to face the sensor 20, like the encoder 10.

The encoder 15 has an annular shape having a predetermined axial width. The sensor facing surface of the encoder 15 is formed by arranging a plurality of N poles 16 in an annular shape at equal intervals. The plurality of N poles 16 are magnetized regions having different magnetic flux densities. An S pole is magnetized on the back side of the sensor facing surface.

The magnetized area forming the encoder 15 has a reference magnetized area having a certain minimum magnetic flux density. Then, each magnetized region is provided with the sensor 2 with the reference magnetized region as a reference.
The magnetic flux density is given so that the magnetic flux density becomes larger from the adjacent magnetized region in the clockwise direction when viewed from 0. In detail,
In this embodiment, as in the first embodiment, the magnetic flux density is given to each magnetized region in accordance with the equation 1.

As described above, the arranged N poles 16 form a magnetic field having a strength according to the polarity and the magnetic flux density of each, around the N poles 16. Therefore, a magnetic field corresponding to the intensity of the magnetic flux density of the N pole is formed around the encoder 15. The position (arrangement angle) of the reference magnetized area of the encoder 15 is stored in a control circuit (not shown) as a reference of the absolute angle of the axis.

The encoder 15 rotates as the shaft 2 rotates. The sensor 20 outputs a current value corresponding to the intensity and direction of the magnetic flux formed by the N pole 16 located at a position facing the sensor 20 to a control circuit (not shown) via the cable 22.

FIG. 6 is a graph showing the output signal detected by the sensor 20. In FIG. 6, the vertical axis represents the intensity of the output signal and the horizontal axis represents time. The magnitude of the output signal is
Proportional to the strength of the magnetic flux, the sign of the output signal is determined by the direction of the magnetic flux. Here, the pulse at the leftmost end in FIG. 6 is a pulse due to the magnetic flux formed by the reference magnetized region.
According to FIG. 6, it can be seen that the intensity of the pulse peak increases stepwise with the passage of time. Therefore, in the case of FIG. 6, the control circuit determines that the shaft 2 is rotating in the direction in which the strength of the N pole 16 is increasing, that is, counterclockwise as viewed from the sensor 20. Then, the control circuit counts the peak number of pulses detected per unit time, and calculates the rotation speed based on the count number and the arrangement interval of the magnetized regions.

Further, the control circuit determines the absolute angle of the axis based on the intensity of the peak of the pulse. In the case of this embodiment, the pulse output from the sensor 20 has a smooth peak on the plane. Therefore, the angular resolution is lower than that of the first embodiment. The control circuit has a threshold value corresponding to the arrangement angle of each magnetized region. Then, when the control circuit detects that the detected value exceeds the threshold value, the control circuit determines that the encoder has passed the corresponding angle.

As described above, according to this embodiment, the encoder 15 and the sensor 20 are arranged so as to face each other in the axial direction. The sensor-facing surface of the encoder 15 has a plurality of Ns arranged so that the magnetic flux density gradually increases.
It is composed of poles 16. Therefore, it is possible to simultaneously detect the rotation speed, the rotation direction, and the rotation angle of the shaft 2 using the single sensor 20.

Therefore, since it is possible to detect the rotation speed, the rotation direction, and the rotation angle of the shaft with a simple structure, it is possible to reduce the number of parts, which leads to a reduction in the parts cost. Further, since the reduction in the number of parts improves the assembling property, the assembling cost can also be reduced.

Furthermore, since the number of sensors is only one, the space of the bearing portion can be saved, and a more compact design can be realized. Further, the reduction in the number of sensors also leads to a reduction in the weight of the bearing, and when used in an automobile or the like, it also contributes to an improvement in fuel consumption.

In this embodiment, the sensor-facing surface of the encoder is composed of only the N poles whose magnetic flux densities successively increase, so the detected peak value is flat.
Therefore, as compared with the case where there is only one peak value, the peak detection error occurrence rate becomes smaller, and it becomes possible to perform detection with higher reliability.

In the present embodiment, the magnetic flux density in the magnetized region is gradually increased. However, a plurality of magnetized region groups whose magnetic flux density is gradually increased are arranged in a plurality of one-to-one rows. You may do it. In this case, the absolute angle of the magnetic flux can be uniquely obtained by counting the number of times the sensor has detected the magnetic flux in the reference magnetized region included in each magnetized region group. Further, in a plurality of magnetized area groups, only the strength of the reference magnetized area may be different. In this case, the absolute angle can be detected by using the intensity of the reference magnetized region detected immediately before as a reference. The same effect can be obtained even if the magnetic flux density in the magnetized region is arranged so as to gradually decrease.

In this embodiment, the sensor facing surface of the encoder is composed of the N pole, but the sensor facing surface of the encoder may be composed of the S pole. In this case, the method of detecting the rotation speed, the rotation direction, and the absolute angle is the same as that of the present embodiment, except that the positive and negative signs of the output signal are reversed.

(Third Embodiment) Hereinafter, a third embodiment of the present invention will be described in detail with reference to FIGS. Here, the same members as those described in the first and second embodiments are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 7 shows a deep groove ball bearing as a rolling device incorporating the rotation detecting device according to the third embodiment of the present invention. The deep groove ball bearing has an outer ring 3, an inner ring 4, a plurality of balls 7 as rolling elements, a seal ring 8 and a cage 9.

In this embodiment, the seal ring 8 is
The space between the outer ring 3 and the inner ring 4 for accommodating the balls 7 is closed by closing one of the openings at both ends. The other end of the opening at both ends of the space for housing the ball 7 is closed and sealed by the encoder holding member 31 and the sensor holding member 41.

The sensor holding member 41 is an annular member having a C-shaped cross section, which has two parallel end portions. The sensor holding member 41 is fixed to the axial end 3c of the outer ring 3,
It projects from the outer ring 3 in the axial direction. Sensor holding member 41
On the inner surface of the upper part in the radial direction of the sensor 40,
Are arranged.

The encoder holding member 31 is an annular member having an L shape in cross section. The encoder holding member 31 is
It is fixed to the axial end 4b of the inner ring 4 and projects from the inner ring 2 in the axial direction. The tip of the sensor holding member 41 is arranged between both ends of the sensor holding member 41. The encoder holding member 31 and the sensor holding member 41 cooperate with each other and play the same role as the seal ring 8. The encoder 30 is arranged on the radial side surface of the encoder holding member 31. The encoder 30 faces the sensor 40 in the radial direction.

FIG. 8 is a perspective view showing the encoder 30, and FIG. 9 is a partially enlarged view thereof. Encoder 30
Has an annular shape whose axial width is larger than its radial width. The encoder 30 includes a plurality of north poles 32 and south poles 3
It is formed by alternately arranging 3 in a circular shape at equal intervals. The plurality of N poles 32 and S poles 33 are magnetized regions having different magnetic flux densities.

The magnetized area forming the encoder 30 has a reference magnetized area having a certain minimum magnetic flux density. Then, each magnetized area is defined by the balls 7 with reference to the reference magnetized area.
The magnetic flux density is given clockwise so that the magnetic flux density is larger than that of the adjacent magnetized region. The magnetic flux density of each magnetized region in the present embodiment is as shown in the above-mentioned formula 1.

The material of the encoder is, for example, an alnico magnet, a ferrite magnet, a samarium / cobalt magnet, a neodymium / iron / boron magnet, or a bond magnet obtained by mixing and molding plastics using various magnet powders. Can be used. Since the magnetic flux density of each magnetized region needs to be different, it is preferable to use a bond magnet whose magnetic flux density can be easily changed. Here, a bond magnet made of plastic containing ferrite powder is used. The magnetic force of the magnet changes depending on the temperature. Therefore, it is necessary to determine the magnetization intensity so that a certain magnetization region does not become the same as the peaks of other magnetization regions within the operating temperature condition.

The N poles 32 and S thus arranged are
The pole 33 forms a magnetic field having an intensity around the pole 33 according to the polarity and magnetic flux density of each pole. Therefore, a magnetic field corresponding to the intensity of the magnetic flux density of the N pole 32 and the S pole 33 is formed around the encoder 30. The position (arrangement angle) of the reference magnetized area of the encoder 30 is stored in a control circuit (not shown) as a reference of the absolute angle of the axis.

The sensor 40 is a magnetic sensor for detecting the magnetic field formed by the encoder 30. The sensor 40 is
It is arranged close to the surface of the encoder 30 and can detect the magnetic field formed by each magnetized region. As the sensor 40, the same sensor as the sensor 20 of the first embodiment can be used.

The encoder 30 rotates as the shaft 2 rotates. The sensor 40 supplies a current value corresponding to the strength and direction of the magnetic flux formed by the N pole 32 or the S pole 33 located at a position facing the sensor 40 to a control circuit (not shown) in the cable 22.
Output via.

The output signal detected by the sensor 20 is equivalent to that shown in FIG. Similar to the first embodiment, the magnitude of the output signal is proportional to the strength of the magnetic flux, and the sign of the output signal is determined by the direction of the magnetic flux. In this case, the control circuit determines that the shaft 2 is rotating in the direction in which the strength of the N pole 32 or the S pole 33 is increasing, that is, counterclockwise as viewed from the ball 7. Then, the control circuit counts the number of peaks detected per unit time, and calculates the rotation speed based on the count number and the arrangement interval of the magnetized regions.

Further, the control circuit determines the absolute angle of the axis based on the intensity of the peak. When the output of the sensor detects a peak (point A or C in FIG. 4), the control circuit
It is determined that the magnetized area corresponding to the detected output faces the sensor 40. Then, the control circuit determines that there is an axis at the absolute angle corresponding to the detected magnetized area.
If the sensor output has a value at point B between the peaks, the absolute angle at point B is calculated from the ratio of the intensity at point A, which is the immediately preceding peak, and the difference in intensity between points A and B. To calculate. Specifically, the angle of the point B is calculated by Equation 2.

As described above, according to this embodiment, the encoder 30 and the sensor 40 are arranged to face each other in the radial direction. The encoder 30 has a plurality of N poles 32 and S poles 3 arranged so that the magnetic flux density gradually increases.
It consists of 3. Therefore, it is possible to simultaneously detect the rotation speed, the rotation direction, and the rotation angle of the shaft 2 using the single sensor 40.

Therefore, since it is possible to detect the rotation speed, the rotation direction, and the rotation angle of the shaft with a simple structure, the number of parts can be reduced and the cost of parts can be reduced. Further, since the reduction in the number of parts improves the assembling property, the assembling cost can also be reduced.

Further, since the number of sensors is only one, the space of the bearing portion can be saved, and the overall design can be made more compact. Further, the reduction in the number of sensors also leads to a reduction in the weight of the bearing, and when used in an automobile or the like, it also contributes to an improvement in fuel consumption.

In the present embodiment, the magnetic flux density in the magnetized region is gradually increased. However, a plurality of magnetized region groups whose magnetic flux density is gradually increased are prepared,
They may be arranged in a line. in this case,
The absolute angle of the magnetic flux can be uniquely obtained by counting the number of times the sensor has detected the magnetic flux in the reference magnetized region included in each magnetized region group. Further, in the plurality of magnetized area groups, only the strength of the reference magnetized area may be different from each other. In this case, the absolute angle can be detected by using the intensity of the reference magnetized region detected immediately before as a reference. The same effect can be obtained even if the magnetic flux density in the magnetized region is arranged so as to gradually decrease.

Further, in this embodiment, the outer ring 3 and the inner ring 4, the encoder 30, and the sensor 40 are integrally formed as a bearing. Therefore, if the encoder and the sensor are assembled to the bearing in advance, the shaft and the housing Assembly is completed simply by placing them in between. Therefore, the assembling efficiency is improved and the assembling cost is reduced.

(Fourth Embodiment) The second embodiment of the present invention will be described below with reference to FIG. Here, the first
~ For the same members as those described in the third embodiment,
The same reference numerals are given and the description thereof is omitted.

FIG. 10 is a partially enlarged view of the encoder 35 used in the rotation detecting device according to the fourth embodiment of the present invention. In the present embodiment, the encoder 35 is arranged to face the sensor 40, like the encoder 30.

The encoder 35 has an annular shape having a predetermined axial width. The sensor facing surface of the encoder 35 is formed by arranging a plurality of N poles 36 in an annular shape at equal intervals. The plurality of N poles 36 are magnetized regions having different magnetic flux densities. The back side of the sensor facing surface is magnetized to the S pole.

The magnetized area forming the encoder 35 has a reference magnetized area having a certain minimum magnetic flux density. Then, each magnetized area is defined by the balls 7 with reference to the reference magnetized area.
The magnetic flux density is given clockwise so that the magnetic flux density is larger than that of the adjacent magnetized region. Specifically, in the present embodiment, the magnetic flux density is given to each magnetized region according to the equation 1 as in the first to third embodiments.

As described above, the arranged N pole 36 forms a magnetic field around the N pole 36 having an intensity corresponding to the polarity and magnetic flux density of each. Therefore, a magnetic field corresponding to the intensity of the magnetic flux density of the N pole is formed around the encoder 35. The position (arrangement angle) of the reference magnetized area of the encoder 35 is stored in a control circuit (not shown) as a reference of the absolute angle of the axis.

The encoder 35 rotates as the shaft 2 rotates. The sensor 40 outputs a current value corresponding to the intensity and direction of the magnetic flux formed by the N pole 36 located at a position facing the sensor 40 to a control circuit (not shown) via the cable 22.

The output signal detected by the sensor 40 is equivalent to that shown in FIG. In FIG. 6, the vertical axis represents the intensity of the output signal and the horizontal axis represents time. The magnitude of the output signal is proportional to the strength of the magnetic flux, and the sign of the output signal is determined by the direction of the magnetic flux. Here, the pulse at the leftmost end in FIG. 6 is a pulse due to the magnetic flux formed by the reference magnetized region. According to FIG. 6, it can be seen that the intensity of the pulse peak increases stepwise with the passage of time. Therefore, in the case of FIG. 6, the control circuit determines that the shaft 2 is rotating in the direction in which the strength of the N pole 36 is increasing, that is, counterclockwise as viewed from the sensor 40. Then, the control circuit counts the peak number of pulses detected per unit time, and calculates the rotation speed based on the count number and the arrangement interval of the magnetized regions.

Further, the control circuit determines the absolute angle of the axis based on the intensity of the peak of the pulse. In the case of this embodiment, the pulse output from the sensor 40 has a smooth peak on the plane. Therefore, the angular resolution is lower than that of the first embodiment, as in the second embodiment. The control circuit has a threshold value corresponding to the arrangement angle of each magnetized region. Then, when the control circuit detects that the detection value exceeds the threshold value, the control circuit determines that the angle corresponding to the encoder has been passed.

As described above, according to this embodiment, the encoder 35 and the sensor 40 are arranged so as to face each other in the axial direction. The sensor-opposing surface of the encoder 35 has a plurality of Ns arranged so that the magnetic flux density gradually increases.
It is composed of the pole 36. Therefore, it is possible to simultaneously detect the rotation speed, the rotation direction, and the rotation angle of the shaft 2 using the single sensor 40.

Therefore, since it is possible to detect the rotation speed, the rotation direction, and the rotation angle of the shaft with a simple structure, it is possible to reduce the number of parts, which leads to a reduction in the parts cost. Further, since the reduction in the number of parts improves the assembling property, the assembling cost can also be reduced.

Furthermore, since the number of sensors is only one, the space of the bearing portion can be saved, and a more compact design can be realized. Further, the reduction in the number of sensors also leads to a reduction in the weight of the bearing, and when used in an automobile or the like, it also contributes to an improvement in fuel consumption.

In the present embodiment, the sensor facing surface of the encoder is composed of only N poles of which the magnetic flux density increases successively, so the detected peak value is flat. Therefore, as compared with the case where there is only one peak value, the peak detection error occurrence rate becomes smaller, and it becomes possible to perform detection with higher reliability.

In the present embodiment, the magnetic flux density in the magnetized area is gradually increased, but a plurality of magnetized area groups whose magnetic flux density is gradually increased are arranged in a plurality of one-to-one rows. You may do it. In this case, the absolute angle of the magnetic flux can be uniquely obtained by counting the number of times the sensor has detected the magnetic flux in the reference magnetized region included in each magnetized region group. Further, in a plurality of magnetized area groups, only the strength of the reference magnetized area may be different. In this case, the absolute angle can be detected by using the intensity of the reference magnetized region detected immediately before as a reference. Further, even if the magnetic flux density in the magnetized region is arranged so as to be gradually reduced, the same effect can be obtained.

Further, in the present embodiment, the sensor facing surface of the encoder is composed of the N pole, but the sensor facing surface of the encoder may be composed of the S pole. In this case, the method of detecting the rotation speed, the rotation direction, and the absolute angle is the same as that of the present embodiment, except that the positive and negative signs of the output signal are reversed.

Further, in the present embodiment, the outer ring 3 and the inner ring 4, the encoder 35, and the sensor 40, which are bearings, are integrally formed. Therefore, if the encoder and the sensor are assembled to the bearing in advance, the shaft and the housing Assembly is completed simply by placing them in between. Therefore, the assembling efficiency is improved and the assembling cost is reduced.

(Fifth Embodiment) The fifth embodiment of the present invention will be described below with reference to FIG. Here, the first
About the same members as the members described in the fourth embodiment,
The same reference numerals are given and the description thereof is omitted.

FIG. 11 shows a deep groove ball bearing as a rolling device incorporating the rotation detecting device according to the fifth embodiment of the present invention. In the present embodiment, the outer ring 3 and the inner ring 4 of the deep groove ball bearing have sensor mounting portions 3 extending in the axial direction, respectively.
d and an encoder mounting portion 4c.

Axial outer surface 4d of the encoder mounting portion 4c
An encoder 50 is arranged above. The encoder 50 can use the encoder 30 or 35 described in the third embodiment or the fourth embodiment. The axial side surface of the encoder 50 faces the sensor mounting portion 3d.

On the other hand, the axial inner surface 3 of the sensor mounting portion 3d
An annular steel plate 85 is erected at the end e. And
An annular seal 80 is supported by the steel plate 85 and seals between the sensor mounting portion 3d and the encoder mounting portion 4c.

Further, a sensor mounting member 75 is arranged on the axially inner side surface 3e of the sensor mounting portion 3d. The sensor mounting member 75 is positioned between the seal ring 8 and the seal 80.

On the sensor mounting member 75, the temperature measuring device 7
0 and a sensor 60 formed of a Hall element or the like is arranged. The sensor 60 faces the encoder 50,
The magnetic flux formed by the encoder 50 is detected. Sensor 60
Detects the magnetic flux and detects the rotation speed, rotation direction, and absolute angle of the rotating body, as in the third and fourth embodiments.

The temperature measuring device 70 measures the temperature of the sensor and the encoder or the peripheral members, and outputs the measured temperature data to a control circuit (not shown). In the magnetized area forming the encoder 50, the magnetic flux density changes due to the temperature change. The control circuit has a table for correcting the change in magnetic flux density due to the change in temperature. Then, the control circuit corrects the output value detected using this table and then detects the rotation speed, rotation direction, and absolute angle of the shaft.
When a contact thermometer such as a thermocouple is used, the temperature of a non-rotating member such as a sensor is detected, but when a non-contact thermometer such as an infrared radiation thermometer is used, the temperature of a rotating member such as an encoder is detected. Is possible.

As described above, according to this embodiment, it is possible to detect the rotation speed, rotation direction, and absolute angle of the shaft by using the output value corrected in consideration of the temperature change. Therefore, the encoder 50 can be used without being aware of the operating temperature condition of the encoder 50, and the present rotation state detecting device can be widely applied to the bearing and the rolling device. The core gap between the encoder and the sensor changes due to expansion or contraction due to heat. The change in the core gap may be corrected based on the signal from the temperature measuring device.

Further, in this embodiment, the encoder 50
The sensor 60 is sealed by the seal ring 8 and the seal 80. Therefore, the influence from the outside world can be minimized, and more accurate measurement can be performed.

Further, the encoder 50 and the sensor 20 are arranged so as to face each other in the axial direction. And encoder 1
Zero is composed of a plurality of N poles 12 and S poles 13 arranged so that the magnetic flux density gradually increases. Therefore, it is possible to simultaneously detect the rotation speed, the rotation direction, and the rotation angle of the shaft 2 using the single sensor 20.

Therefore, since it is possible to detect the rotation speed, the rotation direction, and the rotation angle of the shaft with a simple structure, the number of parts can be reduced and the cost of parts can be reduced. Further, since the reduction in the number of parts improves the assembling property, the assembling cost can also be reduced.

Furthermore, since the number of sensors is only one, the space of the bearing portion can be saved, and the overall design can be made more compact. Further, the reduction in the number of sensors also leads to a reduction in the weight of the bearing, and when used in an automobile or the like, it also contributes to an improvement in fuel consumption.

In the present embodiment, the magnetic flux density in the magnetized region is gradually increased, but a plurality of magnetized region groups whose magnetic flux density is gradually increased are prepared.
These may be arranged in a line. in this case,
The absolute angle of the magnetic flux can be uniquely obtained by counting the number of times the sensor has detected the magnetic flux in the reference magnetized region included in each magnetized region group. Further, in the plurality of magnetized area groups, only the strength of the reference magnetized area may be different from each other. In this case, the absolute angle can be detected by using the intensity of the reference magnetized region detected immediately before as a reference.

[0107]

According to the rotation state detecting device of the first aspect, the plurality of magnetized regions forming the encoder have different magnetic flux densities. Therefore, the rotational speed of the rotating member can be detected by detecting the peak using a single sensor. Further, by grasping the arrangement pattern of the magnetized regions having different magnetic flux densities in advance, it becomes possible to simultaneously detect the rotation direction and the absolute angle of the rotating member using a single sensor. This makes it possible to save space on the stationary member by using a simpler structure than the conventional one. Furthermore, since it is not necessary to provide an extra sensor, it is possible to detect the rotating member at low cost.

According to the rotation state detecting device of the second aspect, since the plurality of N poles and S poles having different magnetic flux densities are alternately arranged, it is possible to emphasize the difference between peaks, which is high. It becomes possible to detect the absolute angle with the angular resolution.

According to the rotation state detecting device of the third aspect, since the sensor facing surface of the encoder is composed only of the N pole or the S pole, the change of the detected value becomes a stepwise increase and the error is small. It becomes possible to perform the measurement.

According to the rotation state detecting device of the fourth and fifth aspects, the encoder faces the sensor in the axial direction or the radial direction of the rotating member. Therefore, a flexible design is possible according to the positional relationship between the rotating member and the stationary member, the shape, etc., and the versatility is high.

According to a sixth aspect of the present invention, the plurality of magnetized regions are arranged so that the magnetic flux density gradually increases or decreases gradually. Since the detected value changes regularly as the magnetic flux density gradually increases, the processing of the detected data becomes easy.

According to the rotation state detecting device of the seventh aspect, a temperature measuring section for measuring the temperature of the sensor or the encoder or their peripheral members is further provided. Therefore, the detected value can be corrected according to the change in the magnetic flux density in the magnetized region due to the change in ambient temperature. Therefore, it is possible to perform a more accurate measurement.

According to the rotating state detecting device of the eighth aspect, a seal member for sealing the encoder and the sensor is further provided. Therefore, it is possible to cut off the encoder and the sensor from the outside world to minimize the influence of disturbance. Therefore, the measurement accuracy is improved.

According to the rolling device according to claims 9 to 16 of the present invention, the rotation state detecting device according to claims 1 to 8 is incorporated. In the rolling device incorporating the rotation state detecting device according to any one of claims 1 to 8, the plurality of magnetized regions forming the encoder have different magnetic flux densities from each other. Therefore, the rotational speed of the rotating member can be detected by detecting the peak using a single sensor. further,
By grasping the arrangement pattern of the magnetized regions having different magnetic flux densities in advance, it becomes possible to detect the rotation direction and the absolute angle of the rotating member at the same time using a single sensor. This makes it possible to save space on the stationary member by using a simpler structure than the conventional one.
Furthermore, since it is not necessary to provide an extra sensor, it is possible to detect the rotating member at low cost.

[Brief description of drawings]

FIG. 1 shows a deep groove ball bearing as a rolling device incorporating a rotation detection device according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an encoder 10.

FIG. 3 is a partially enlarged view of the encoder 10.

FIG. 4 is a graph showing an output signal detected by the sensor 20.

FIG. 5 is a partially enlarged view of an encoder 15 used in the rotation detection device according to the second embodiment of the present invention.

FIG. 6 is a graph showing an output signal detected by the sensor 20.

FIG. 7 shows a deep groove ball bearing as a rolling device incorporating a rotation detecting device according to a third embodiment of the present invention.

FIG. 8 is a perspective view showing an encoder 30.

9 is a partially enlarged view of the encoder 30. FIG.

FIG. 10 is a partially enlarged view of an encoder 35 used in the rotation detection device according to the fourth embodiment of the present invention.

FIG. 11 shows a deep groove ball bearing as a rolling device incorporating a rotation detecting device according to a fifth embodiment of the present invention.

[Explanation of symbols]

1 housing 2 axes 3 outer ring 4 inner ring 5 Outer ring track 6 Inner ring track 7 balls 8 seal ring 9 cage 10, 15, 30, 35, 50 encoder 20, 25, 40, 45, 60 sensor

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F034 AA09 EA01 EA04 EA05 EA14                       EA21                 2F077 AA27 AA37 CC02 NN04 NN24                       PP06 PP12 VV33

Claims (16)

[Claims] 1. An encoder that is attached to a rotating member that rotates with respect to a stationary member, and that is composed of a plurality of magnetized regions that are arranged in a row; and an encoder that is attached to the stationary member and that faces the encoder, A rotation state detecting device having a sensor for detecting magnetic forces of the plurality of magnetized regions of the encoder, wherein the plurality of magnetized regions have different magnetic flux densities from each other. 2. The rotation state detecting device according to claim 1, wherein the plurality of magnetized regions of the encoder are constituted by a plurality of N poles and S poles which are alternately arranged. 3. The rotation state detecting device according to claim 1, wherein the plurality of magnetized regions of the encoder are composed of N poles or S poles. 4. The encoder is opposed to the sensor in an axial direction of a rotating member.
3. The rotation state detection device described in 3. 5. The encoder is opposed to the sensor in a radial direction of a rotary member.
3. The rotation state detection device described in 3. 6. The rotation state detecting device according to claim 1, wherein the plurality of magnetized regions are arranged such that the magnetic flux density gradually increases or gradually decreases. 7. The rotation state detecting device according to claim 1, further comprising a temperature measuring unit that measures the temperature of the sensor, the encoder, or the peripheral member. 8. The rotation state detecting device according to claim 1, further comprising a seal member that seals the encoder and the sensor. 9. A stationary member, a rotating member that rotates with respect to the stationary member, an encoder that is attached to the rotating member and is composed of a plurality of magnetized regions arranged in a row, and attached to the stationary member. And a sensor that faces the encoder and that detects the magnetic forces of the plurality of magnetized regions of the encoder, wherein the plurality of magnetized regions have different magnetic flux densities from each other. Rolling device. 10. The plurality of magnetized regions of the encoder are
The rolling device according to claim 9, comprising a plurality of N poles and S poles arranged alternately. 11. The rolling device according to claim 9, wherein the plurality of magnetized regions of the encoder are constituted by N poles or S poles. 12. The encoder is opposed to the sensor in an axial direction of a rotary member.
~ 11 rolling device. 13. The encoder is opposed to the sensor in a radial direction of a rotating member.
~ 11 rolling device. 14. The rolling device according to claim 9, wherein the plurality of magnetized regions are arranged such that the magnetic flux density is gradually increased or gradually decreased. 15. The rolling device according to claim 9, further comprising a temperature measuring unit for measuring the temperature of the sensor, the encoder or their peripheral members. 16. A seal member for sealing the encoder and the sensor is further provided.
The rolling device according to any one of items 1 to 15.