JP2007248106A - Rotation angle detector with rotational speed signal output and bearing with detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation angle detector with a rotational speed signal output for detecting a rotational speed besides a rotation angle without using any external circuit, and a bearing with a detector with this angle detector built therein. <P>SOLUTION: A magnet with a pair of magnetic poles formed therein is disposed on a shaft end of a rotary shaft relative to a fixed member. Magnetic sensors 5A to 5D each comprising a large scale integrated circuit are provided on the fixed member to axially confront the magnet. A rotation angle detector is formed by therefor providing an angle calculation means 7 detecting a rotation angle of the rotary shaft from outputs of the magnetic sensors 5A to 5D. Further, a rotational speed calculation means 8 is provided for calculating a rotational speed ω from a time change in the rotation angle θ detected by the calculation means 7, and a speed signal output means 11 is provided for outputting the signal of the rotational speed ω calculated by the calculation means 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to rotation angle detection in various devices, for example, rotation angle detection for rotation control of a small motor, rotation angle detection for office device position detection, detection of a robot joint angle, and the like. The present invention relates to a detection device and a bearing with a detection device incorporating the rotation angle detection device.

As a rotation angle detection device that can be incorporated into a small device and can detect a rotation angle with high accuracy, a device using a magnetic sensor array has been proposed (for example, Patent Document 1). As shown in FIG. 9, a magnetic sensor array 35 configured by arranging a large number of magnetic sensor elements (MAGFETs) is integrated in a sensor chip 39 together with a circuit 36 such as a signal amplification circuit, an AD conversion circuit, and a digital signal processing circuit. The sensor chip 39 is disposed so as to face the magnet 34 disposed on the rotation side member 31. In this case, the magnet 34 has circumferential anisotropy around the rotation center O, and on the sensor chip 39, the magnetic sensor array 35 is arranged along each side of the four sides of the virtual rectangle. .
In the rotation angle detection device 33 configured as described above, the output of the magnetic sensor array 35 on each side is read by a signal amplification circuit and an AD conversion circuit to detect the magnetic field distribution of the magnet 34, and the magnet 34 is based on the detection result. Is calculated by a digital signal processing circuit.
JP 2003-37133 A

  In the operation of the rotation angle detection device having the above configuration, a cycle of magnetic field measurement → angle calculation → angle output is repeated, and therefore angle data is output at a constant time interval corresponding to the cycle. Therefore, when the rotational speed of the rotating body is detected using this rotational angle detection device, it is necessary to calculate the amount of change in the output angle data per measurement time interval and convert it to the rotational speed. However, such processing requires a calculation circuit or a calculation by a microcomputer, and an external circuit has to be prepared.

  An object of the present invention is to provide a rotation angle detection device with a rotation speed signal output capable of detecting a rotation speed in addition to a rotation angle without using an external circuit, and a bearing with a detection device incorporating the rotation angle detection device. It is.

In the rotation angle detection device with a rotation speed signal output of the present invention, a magnet in which a pair of magnetic poles is formed is arranged at the end of the rotation axis of a rotating body that is rotatable with respect to a fixed member. In the rotation angle detection device provided with a magnetic sensor composed of a large-scale integrated circuit facing the fixed member and provided with an angle calculation means for detecting the rotation angle of the rotating body from the output of the magnetic sensor, the angle calculation means Rotational speed calculation means for calculating the rotational speed from the detected temporal change of the rotational angle, and speed signal output means for outputting a rotational speed signal calculated by the rotational speed calculation means are provided.
According to this configuration, the angle calculation means detects the rotation angle of the rotating body based on the output of the magnetic sensor, and the rotation speed calculation means calculates the rotation speed from the time change of the rotation angle detected by the angle calculation means. The rotation speed signal is output by the speed signal output means. For this reason, rotation speed information that could not be detected without using an external circuit such as a separately installed microcomputer or calculation processing circuit can be output together with the rotation angle information from one rotation angle detection device. And a highly convenient detection device.

  In the present invention, the magnetic sensor comprising the large-scale integrated circuit may be a magnetic sensor array. With a magnetic sensor array, small and accurate angle detection can be performed. Further, it may have a serial communication circuit serving as the speed signal output means.

  In the present invention, the speed signal output means may convert the speed, which is a calculation result by the rotational speed calculation means, so as to change within a set upper limit value and lower limit value range. In the case of this configuration, for example, conversion is possible in which the rotational speed 5000 rpm is made to correspond to a voltage of 5 V by setting an upper limit value, the stop state is made to correspond to a voltage of 0 V by setting the lower limit value, and the value therebetween is linearly corresponded. .

  In the present invention, the speed signal output means may be capable of switching the signal conversion method of the output rotational speed between linear conversion and logarithmic conversion by setting.

  In this invention, the speed signal output means may be capable of switching the form of the output rotational speed signal by setting. In the case of this configuration, a wide range can be supported according to the environment to be used and the connected equipment.

In the present invention, the speed signal output means may output at least two types of voltage output, current output, and PWM (pulse width modulation) output in the form of a rotational speed signal.
In the case of this configuration, for example, when voltage output is selected, a voltage corresponding to the rotation speed is output, so that it can be used similarly to a tachometer generator or the like. In addition, when there are many noise sources in the surrounding environment of the rotation angle detection device, when the current output is set, a current that changes according to the rotation speed is output, and the signal form is less susceptible to noise. The PMW output is a signal output whose output pulse width changes according to the rotation speed.

  In the present invention, there may be provided an external setting means for performing setting related to conversion or output of the speed signal output means from the outside by communication. Here, “external” is external to the speed signal output means. In the case of this configuration, since the setting relating to the conversion or output of the speed signal output means can be changed from the outside by communication, one rotation angle detection device can be adapted to various applications.

  In the present invention, setting content storage means for storing the content set by the external setting means in a nonvolatile memory is provided inside or outside the large-scale integrated circuit constituting the magnetic sensor, and the setting content storage means is turned on. Sometimes, the contents stored in the nonvolatile memory may be read and used as the setting contents of the rotation speed calculation means or the speed signal output means. In the case of this configuration, the contents set by the external setting means are stored in the nonvolatile memory of the setting contents storage means, so that each setting value once set is always used as the setting contents of the speed signal output means in that state. be able to.

The bearing with a detection device according to the present invention is obtained by incorporating the rotational angle detection device with a rotational speed signal output according to any one of the above configurations of the present invention into a bearing.
According to this configuration, it is possible to reduce the number of parts, the number of assembling steps, and the size of the bearing using device. In that case, since the rotation angle detection device can detect the rotation angle and the rotation speed, it can be used for a wide range of applications.

In the rotation angle detection device with a rotation speed signal output of the present invention, a magnet in which a pair of magnetic poles is formed is arranged at the end of the rotation axis of a rotating body that is rotatable with respect to a fixed member. In the rotation angle detection apparatus, wherein the fixed member is provided with the sensor composed of a large-scale integrated circuit, and angle calculation means for detecting the rotation angle of the rotating body from the output of the sensor is provided. A rotation speed calculation means for calculating the rotation angle from the time change of the detected rotation angle and a speed signal output means for outputting a signal of the rotation speed calculated by the rotation speed calculation means are provided, so that rotation can be performed without using an external circuit. Not only the angle but also the rotation speed can be detected.
Since the bearing with a detection device of the present invention incorporates the rotation angle detection device with a rotational speed signal output of the present invention into the bearing, the number of parts of the bearing-use equipment, the number of assembling steps can be reduced, and compactness can be achieved. Can be used.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of a bearing incorporating the rotational angle detection device with rotational speed signal output of this embodiment. This bearing 20 with a detecting device is a rolling bearing in which a rolling element 24 held by a cage 23 is interposed between rolling surfaces of an inner ring 21 and an outer ring 22. The rolling element 24 is formed of a ball, and the rolling bearing 20 is a single row deep groove ball bearing. A rotating shaft 10 that is a rotating body is fitted in the inner ring 21 in a press-fitted state, and the outer ring 22 is installed in a housing (not shown) of a bearing-using device.

The rotation angle detection device 1 with a rotational speed signal output incorporated in the rolling bearing 20 includes a magnet 2 disposed on the inner ring 21 side of the rolling bearing 20 and a rotation sensor 3 disposed on the outer ring 22 side. Specifically, the permanent magnet 2 having a pair of magnetic poles N and S is disposed at the end of the rotational axis of the rotary shaft 10 that rotates together with the inner ring 21, and the sensor mounting member 27 that is in a fixed relationship with the outer ring 22 is disposed on the sensor mounting member 27. A rotation sensor 3 is arranged.
As shown in FIG. 2, the magnet 2 has a direction in which the magnetism generated from the pair of magnetic poles N and S is around the axis O of the rolling bearing 20. The magnet 2 is fixed to the center of one end of the rotating shaft 10 so that the axis O of the rolling bearing 20 coincides with the center of the magnet 2. When the magnet 2 rotates integrally with the rotary shaft 10, the N magnetic pole and the S magnetic pole pivot around the bearing axis O.

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

  The rotation sensor 3 is an integrated circuit in which a plurality of magnetic sensor elements are integrated, and detects the rotation angle of the magnet 2 by detecting the direction or intensity distribution of the magnetic field applied to the semiconductor chip. A magnetic sensor array as shown in a plan view in FIG. 3 may be used, and a large-scale integrated circuit is integrated on one semiconductor chip 4. The large-scale integrated circuit includes a plurality of magnetic sensor elements 5a constituting the magnetic sensor 5, and an arithmetic circuit unit 6 that calculates and outputs a rotation angle and a rotation speed from the output of the magnetic sensor element 5a. On the semiconductor chip 4, the magnetic sensor elements 5 a are arranged along each side of the four sides on the virtual rectangle to form the four-side magnetic sensor arrays 5 </ b> A to 5 </ b> D. In this case, the center O ′ of the rectangle coincides with the axis O of the rolling bearing 20. In the four-side magnetic sensor arrays 5A to 5D, the sensor elements 5a are arranged in a line in the example shown in the figure, but the sensor elements 5a may be arranged in parallel in a plurality of lines. The arithmetic circuit unit 6 is arranged inside the rectangular arrangement of the magnetic sensor arrays 5A to 5D. The semiconductor chip 4 is fixed to the sensor mounting member 27 so that the element formation surface faces the magnet 2.

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

4 and 5 are explanatory diagrams of a rotation angle calculation process by the angle calculation means 7 (FIG. 7) in the arithmetic circuit unit 6. FIG. 5A to 5D show output waveform diagrams of the magnetic sensor arrays 5A to 5D when the rotary shaft 10 is rotating, and the horizontal axes thereof are magnetic sensor elements in the magnetic sensor arrays 5A to 5D. 5a, the vertical axis indicates the intensity of the detected magnetic field.
Now, assume that there are zero-cross positions at the positions X1 and X2 shown in FIG. 4 that are the boundaries between the N magnetic pole and the S magnetic pole of the detected magnetic field of the magnetic sensor arrays 5A to 5D. In this state, the outputs of the magnetic sensor arrays 5A to 5D have signal waveforms shown in FIGS. Therefore, the zero cross positions X1 and X2 can be calculated by linear approximation from the outputs of the magnetic sensor arrays 5A and 5C.
The angle calculation can be performed by the following equation (1).
θ = tan ⁻¹ (2 L / b) (1)
Here, θ is a value indicating the rotation angle θ of the magnet 2 as an absolute angle (absolute value). 2L is the length of one side of a quadrangle composed of the magnetic sensor arrays 5A to 5D arranged in a rectangle. b is the lateral length between the zero-cross positions X1 and X2.
When the zero-cross positions X1 and X2 are in the magnetic sensor arrays 5B and 5D, the rotation angle θ is calculated in the same manner as described above based on the zero-cross position data obtained from the outputs. The rotation angle θ calculated by the arithmetic circuit unit 6 is output by the output cable 29 or the serial communication circuit 12 (FIG. 7) described later.

  FIG. 6 is a timing chart illustrating a processing operation cycle in which the rotation sensor 3 detects and outputs the rotation angle θ. In the first half section Ta of the time T of one cycle, the magnetic sensor arrays 5A to 5D, which are the magnetic sensors of the rotation sensor 3, sample the magnetic field of the magnet 2 on the rotation side, and in the second section Tb of the one cycle, The angle calculation means 7 (FIG. 7) of the arithmetic circuit unit 6 calculates the rotation angle θ from the sampled value and outputs it. As described above, since the sampling of the magnetic field is repeatedly performed every time T, the rotation angle θ calculated from each sampling value is also output every time T.

  The rotation speed calculation means 8 (FIG. 7) in the arithmetic circuit section 6 obtains the amount of change from the data of the rotation angle θ output every time T as described above, so that the magnet 2, that is, the rotation shaft 10. Calculate the rotation speed.

FIG. 7 is a block diagram showing the circuit configuration of the rotation sensor 3. Magnetic data sampled by the magnetic sensor arrays 5 </ b> A to 5 </ b> D is amplified and AD converted and input to the arithmetic circuit unit 6. The angle calculation means 7 in the arithmetic circuit unit 6 calculates the rotation angle θ by performing the arithmetic processing shown in FIGS. 4 and 5 based on the sampling values by the magnetic sensor arrays 5A to 5D.
On the other hand, the rotation speed calculation means 8 in the arithmetic circuit unit 6 stores the data of the rotation angle θ output from the angle calculation means 7 every time T in the memory 9 and calculates the change in the data to calculate the rotation speed. Obtain ω and rotation direction. The calculation is performed as follows.
When the sampling rotation angle θ (n) is changed every time, the rotation speed ω can be obtained from the change angle between successive samplings as shown in the following equation (2).
ω = {θ (n + 1) −θ (n)} / T (2)
However, θ (n) and θ (n + 1) represent rotation angles obtained by the n-th and (n + 1) -th sampling.
When the rotation speed is low and the rotation angle θ (n) does not change in every sampling, the rotation speed ω is obtained from the angle change amount between several to several tens of samplings as shown in the following equation (3). be able to.
ω = {θ (n + m) −θ (n)} / mT (3)
However, (theta) (n + m) represents the rotation angle calculated | required by the (n + m) sampling.
The rotational speed ω data thus obtained is input to an output circuit 11 which is a speed signal output means, where it is converted into a rotational speed signal in a predetermined signal form and output to the outside. The setting of the output signal form is performed by storing the output signal form in the setting memory 13 as the setting content storage means via the serial communication circuit 12 from the external setting means 25 provided outside the rotation sensor 3. The setting memory 13 has a nonvolatile memory. Here, the serial communication circuit 12 is provided on the semiconductor chip 4 as a part of the arithmetic circuit unit 6 configured as a large-scale integrated circuit together with the magnetic sensor arrays 5A to 5D. 4 may be provided outside.

FIG. 8 is a block diagram showing details of the output circuit 11 in FIG. In the setting memory 13, via the serial communication circuit 12 from the external setting means 25 (FIG. 7), in addition to the output signal form, a speed upper limit set value 14A, a speed lower limit set value 14B, and a conversion (not shown) Setting values of the calculation method (designating logarithmic conversion or linear conversion) are stored, and these setting values are read out when the power is turned on. Depending on the speed upper limit set value 14A, the speed lower limit set value 14B, and the conversion calculation method, the output conversion circuit 15 of the output circuit 11 uses the rotation speed ω data provided from the rotation speed calculation means 8 (FIG. 7) as the rotation speed. Convert to signal. The output signal may be a digital signal or an analog signal. For example, the conversion is performed such that the rotation speed 5000 rpm corresponds to a voltage of 5V by the upper limit value setting 14A, the stop state corresponds to the voltage of 0V by the lower limit value setting 14B, and the value therebetween corresponds linearly.
The converted rotation speed signal selectively turns on the switches 19A to 19C in accordance with the output signal form set in the setting memory 13, and any one of the voltage output circuit 16, the current output circuit 17, and the PWM output circuit 18 is selected. By selecting, the output is switched to voltage output, current output, or PWM output and output to the outside. For example, when the voltage output is selected, a voltage corresponding to the rotation speed ω is output, so that it can be used in the same manner as a tachometer generator. In addition, when there are many noise sources in the surrounding environment of the rotation angle detection device 1, when the current output is set, a current that changes in accordance with the rotation speed ω is output, and the signal form is less susceptible to noise. The PMW output is a signal output whose output pulse width changes according to the rotational speed ω. In this case, since the setting memory 13 has a non-volatile memory, each setting value once set can always be used in that state.
In this embodiment, the rotational speed ω data is output to the outside through the serial communication circuit 12. Therefore, the serial communication circuit 12 and the output circuit 11 constitute speed signal output means for outputting a signal of the rotational speed ω to the outside.

As described above, the rotation angle detection device 1 with the rotation speed signal output includes the rotation speed calculation means 8 for calculating the rotation speed ω from the time change of the rotation angle θ detected by the angle calculation means 7. Since the speed signal output means 26 that outputs the signal of the calculated rotational speed ω of 8 is provided, information on the rotational speed ω that could not be detected without using a separately installed microcomputer or calculation processing circuit is conventionally provided. Since the rotation angle θ can be output from one rotation angle detection device 1 together with the rotation angle θ, a highly convenient detection device can be obtained.
In this embodiment, since the speed signal output means 11 can switch the form of the output rotational speed ω signal by setting, the rotational speed can be output in an output form corresponding to the environment to be used and the connected device. A signal can be taken out, and it can respond widely according to the application.
In addition, since the external setting means 25 that enables the setting related to the conversion or output of the speed signal output means 11 to be set from outside by communication is provided, the setting can be easily changed from the outside, and one rotation angle detecting device 1 can adapt to various applications.

  Moreover, according to the bearing 20 with a detection device in which the rotation angle detection device 1 with a rotation speed signal output is integrated, the number of parts and the number of assembling steps of the bearing using device can be reduced and the size can be reduced. In that case, since the rotation angle detection apparatus 1 can detect the rotation angle θ and the rotation speed ω, it can be used for a wide range of applications.

It is sectional drawing of the bearing with a detection apparatus incorporating the rotation angle detection apparatus with a rotational speed signal output which concerns on one Embodiment of this invention. It is an enlarged side view which shows the magnet fixing | fixed part in the same bearing. It is a top view of the semiconductor chip which constitutes an example of the rotation sensor in the bearing. It is explanatory drawing of the angle calculation process by the angle calculation means of the rotation sensor. It is a wave form diagram which shows the output of the magnetic sensor array in the rotation sensor. It is a timing chart which shows the cycle of the processing operation which the rotation sensor detects and outputs a rotation angle. It is a block diagram which shows the circuit structure of the rotation sensor. It is a block diagram which shows the detail of the output circuit in FIG. It is a perspective view of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotation angle detection apparatus 2 with a rotational speed signal output ... Magnet 5 ... Magnetic sensors 5A-5D ... Magnetic sensor array 7 ... Angle calculation means 8 ... Rotation speed calculation means 10 ... Rotating shaft (rotating body)
11 ... Speed signal output means 12 ... Serial communication circuit 13 ... Setting memory (setting content storage means)
20 ... Rolling bearing (bearing with detection device)
25 ... External setting means 27 ... Sensor mounting member (fixing member)

Claims (10)

A magnet having a pair of magnetic poles is disposed at the end of the rotational axis of a rotating body that is rotatable with respect to the fixed member, and a magnet composed of a large-scale integrated circuit is disposed on the fixed member so as to face the magnet in the axial direction. In the rotation angle detection device provided with the sensor and provided with the angle calculation means for detecting the rotation angle of the rotating body from the output of the magnetic sensor,
Rotational speed calculation means for calculating the rotational speed from the time change of the rotational angle detected by the angle calculation means, and speed signal output means for outputting a signal of the rotational speed calculated by the rotational speed calculation means are provided. A rotation angle detection device with a rotation speed signal output.   The rotation angle detection device with a rotation speed signal output according to claim 1, wherein the magnetic sensor comprising the large-scale integrated circuit is a magnetic sensor array.   3. The rotation angle detection device with a rotation speed signal output according to claim 1, further comprising a serial communication circuit serving as the speed signal output means.   4. The speed signal output means according to claim 1, wherein the speed signal output means converts the speed calculated by the rotational speed calculation means so as to change within a set upper limit value and lower limit value range. A rotation angle detection device with a rotation speed signal output.   5. The rotation angle detection device with a rotation speed signal output according to claim 4, wherein the speed signal output means is capable of switching a signal conversion method of a rotation speed to be output between linear conversion and logarithmic conversion by setting.   3. The rotation angle detection device with a rotation speed signal output according to claim 1, wherein the speed signal output means is capable of switching a form of a rotation speed signal to be output by setting.   3. The rotation angle with rotation speed signal output according to claim 1 or 2, wherein the speed signal output means outputs at least two types of voltage output, current output, and PWM output in the form of a rotation speed signal to be output. Detection device.   8. A rotation angle with a rotation speed signal output according to claim 5, 6 or 7, wherein an external setting means is provided for externally setting the conversion or output of the rotation speed calculation means or speed signal output means by communication. Detection device.   9. The setting content storage means for storing the content set by the external setting means in a nonvolatile memory is provided inside or outside a large-scale integrated circuit constituting the magnetic sensor, and the setting content storage means A rotation angle detection device with a rotation speed signal output that reads the stored contents of the non-volatile memory at the time of turning on and uses them as the setting contents of the rotation speed calculation means or the speed signal output means.   A bearing with a detection device, wherein the rotation angle detection device with a rotation speed signal output according to any one of claims 1 to 9 is incorporated in the bearing.

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