JP4992691B2 - Rotation / linear motion combined motor position detector and rotational / linear motion combined motor - Google Patents

Description

The present invention relates to a position detection device for a combined rotation / linear motion motor that detects the position of an output shaft of the combined rotation / linear motion motor, and a combined rotation / linear motion motor.

2. Description of the Related Art Conventionally, a rotation / linear motion combined motor that detects the rotation and linear motion positions of an output shaft of a rotation / linear motion combined motor using separate position detection devices has been disclosed (for example, see Patent Document 1). .
FIG. 7 is a side sectional view showing a structure of a position detecting device for rotation of a conventional combined rotary / linear motion motor, and FIG. 8 is a side sectional view showing a structure of a position detecting device for linear motion.

First, the structure of the position detection device for rotation will be described.
In FIG. 7, 1 is a motor unit, and 21 is a position detection device for rotation.
In the motor unit 1, 16 is a rotary / linear motion bearing, and the output shaft 9 is supported so as to be movable in the rotational direction and the linear motion direction.

  In the position detection device 21 for rotation, 3 is a linear motion bearing and 4 is a rotation bearing. The linear motion bearing 3 has a ball spline bearing structure, the inner race side being fixed to the output shaft 9, and the outer race side being rotatably attached to and supported by the rotary bearing 4. Reference numeral 5 denotes a rotation signal generator fixed to the outer race side of the linear motion bearing 3, and the rotation signal generator 5 rotates in synchronization with the linear motion bearing 3 to generate a rotation signal of the output shaft 9. Reference numeral 6 denotes a rotation signal detector. The rotation signal detector 6 receives a signal from the rotation signal generator 5 at a fixed position and detects the rotation position of the output shaft 9.

Next, the structure of the position detecting device for linear motion will be described.
In FIG. 8, 22 is a position detector for linear motion.
In the position detector 22 for linear motion, 7 is a linear motion signal generator, which moves in synchronism with the linear motion bearing 3 only in the linear motion direction of the output shaft 9, thereby converting the linear motion signal of the output shaft 9. appear. The linear motion bearing 3 supports the lower end portion of the output shaft 9 of the motor via the rotary bearing 4. A linear motion signal detector 8 receives a signal from the linear motion signal generator 7 at a fixed position, and detects the linear motion position of the output shaft 9.

As described above, the conventional combined rotary / linear motor has detected the rotational position and the linear motion position of the output shaft using different devices.
JP 2000-14115 A

  However, the conventional rotary / linear motion type motor position detection device is provided with separate rotation and linear motion position detection devices, which are combined to form a problem that it is difficult to reduce the size. there were. The present invention has been made in view of such problems, and an object of the present invention is to realize a small-sized linear motion / composite motor position detection device.

In order to solve the above problems, the present invention is configured as follows.
That is, a position detection device for a combined rotary / linear motion motor according to an aspect of the present invention includes a motor unit having an output shaft that moves in the rotational direction and the linear motion direction, and the rotational position and linear motion position of the output shaft. In the position detection device of the rotary / linear motion combined motor configured with the position detection device to detect, the position detection device is disc-shaped and magnetized in one direction horizontally with respect to the disc-shaped plane, A plurality of position detecting magnets arranged at equal intervals with the plane perpendicular to the linear motion direction so that adjacent magnetization directions are reversed from each other are provided.
The position detection device for a combined rotary / linear motion motor according to the first aspect is characterized in that the position detection device is a first hole disposed with a gap with respect to a circumferential side surface of the position detection magnet. An element, a second hall element disposed at a position rotated by 90 degrees in the circumferential direction from the position of the first hall element, and the position detecting magnet in the linear motion direction from the position of the first hall element A third Hall element disposed at a position separated by a half pitch of the magnetic pole pitch of the first Hall element, and determining the rotational position from the output voltage of the first Hall element and the second Hall element, The linear motion position may be obtained from output voltages of one hall element and the third hall element .
Further, the position detection device of the combined rotary / direct motion type motor according to the above one aspect obtains the rotational position by calculating an arctangent of output voltages of the first hall element and the second hall element, and the linear motion The position may be obtained by calculating an arctangent of output voltages of the first Hall element and the third Hall element .
The position detection device for a combined rotary / linear motion motor according to the first aspect is characterized in that the position detection device is a first hole disposed with a gap with respect to a circumferential side surface of the position detection magnet. An element, a second hall element disposed at a position rotated by 90 degrees in the circumferential direction from the position of the first hall element, and the position detecting magnet in the linear motion direction from the position of the first hall element A third Hall element disposed at a position separated from the magnetic pole pitch by ½ pitch, and a ½ pitch of the magnetic pole pitch of the position detecting magnet in the linear motion direction from the position of the second Hall element. A fourth Hall element disposed at a separated position, the output voltage of the first Hall element and the second Hall element, or the output voltage of the third Hall element and the fourth Hall element To determine the rotational position from Wherein the one Hall element output voltage of the third Hall element, or may also be characterized by determining the linear motion position from the output voltage of the said and second Hall elements fourth hall elements.
In addition, the position detection device of the rotary / linear motion combined motor according to the one aspect described above is an arctangent calculation of output voltages of the first Hall element and the second Hall element, or the third Hall element and the Obtained by the arc tangent calculation of the output voltage of the fourth Hall element, the linear motion position arc tangent calculation of the output voltage of the first Hall element and the third Hall element, or the second Hall element and the The fourth Hall element may be obtained by calculating an arctangent of the output voltage of the fourth Hall element .
According to another aspect of the present invention, there is provided a combined rotary / direct acting motor, comprising the position detecting device for the combined rotary / direct acting motor according to the first aspect.

According to the position detection device for a combined rotary / linear motion motor according to one aspect of the present invention , the position detection device is magnetized in one direction in a horizontal direction with respect to a disk-shaped plane, and adjacent magnetizations. Since it has a plurality of position detection magnets arranged at equal intervals with the disk-shaped plane perpendicular to the linear motion direction so that the directions are reversed, both the rotational and linear motion position detection of the output shaft Thus, the position detection device can be reduced in size.

Further , according to the position detection device for the combined rotation / linear motion motor according to the above one aspect, if the position detection of both the rotation and the linear motion of the output shaft is performed only by the position detection magnet and the four Hall elements, The detection apparatus can be reduced in size, and the detection accuracy of an arbitrary rotational position / linear motion position can be improved.

In addition, according to the combined rotation / linear motion motor according to another aspect of the present invention, a combined rotation / linear motion motor including a small position detection device can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional side view of a combined rotary / linear motion motor showing a first embodiment of the present invention.
In FIG. 1, the combined rotary / linear motor includes a motor unit 1 and a position detection device 2. In the motor unit 1, the output shaft 9 is supported by the rotary / linear motion bearing 16 so that the output shaft 9 can move in the rotational direction and the linear motion direction. The position detection device 2 detects the absolute position of rotation and linear motion of the output shaft 9.

The position detection device 2 includes a plurality of position detection magnets and three Hall elements.
2 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 3 is a side cross-sectional view of the position detection device portion of FIG. FIG. 4 is a perspective view schematically showing the arrangement of position detection magnets and three Hall elements of the position detection apparatus in the present embodiment. However, the output shaft 9 is omitted.
In FIG. 2, reference numeral 10 denotes a position detecting magnet which has a disk shape and is magnetized in one direction in the horizontal direction with respect to the plane of the disk.
Further, in FIG. 3, the plurality of disk-shaped permanent magnets have their disk-shaped planes in the linear motion direction so that a magnetic pole pitch 19 equal to the interval between the permanent magnets adjacent to the linear motion direction is formed. The magnets were arranged so as to be perpendicular to each other at equal intervals, and further arranged so that the magnetization directions 15 were alternately reversed.

  2 and 3, 11 is a first Hall element, 12 is a second Hall element, and 13 is a third Hall element. The first hall element 11 is arranged with a gap with respect to the side surface in the circumferential direction of the position detection magnet 10, and the second hall is located at a position rotated by 90 degrees in the circumferential direction from the position of the first hall element 11. The element 12 is arranged, and the third hall element 13 is arranged at a position separated from the position of the first hall element 11 by a ½ pitch 20 of the magnetic pole pitch 19 of the position detecting magnet 10 in the linear motion direction.

Next, the principle of detecting the rotational position and linear motion position of the output shaft 9 will be described.
The first Hall element 11 fixed at a fixed position detects the magnetic field generated from the position detection magnet 10 as a component in a direction perpendicular to the sensitive surface of the Hall element. Here, when the linear movement position z of the output shaft 9 is fixed and the rotational position θ is changed, the magnitude of the magnetic field detected by the Hall element changes in a sine wave shape according to the magnitude of the rotational position θ, and at the same time, the Hall The output voltage V1 of the element is also a sine wave with respect to the rotational position θ. When the rotational position θ is fixed and the linear motion position z is changed, the output voltage V1 of the first Hall element 11 becomes a sine wave with respect to the linear motion position z.

Therefore, the output voltage V1 of the first Hall element 11 with respect to the rotational position θ and the linear movement position z of the output shaft 9 is as shown in the graph of FIG.
V1 = sin θ · sinz (1)
Here, the linear motion position z of the output shaft 9 is expressed by an electrical angle in which the magnetic pole pitch 19 of the position detection magnet 10 corresponds to an angle of 180 degrees, and the amplitude of the output voltage of the Hall element is 1 [V]. Was set.
FIG. 2 shows a case where 17 is the origin of the rotational position θ and the rotational position θ of the output shaft 9 with respect to the first Hall element 11 is 90 degrees. 3 shows a case where 18 is the origin of the linear motion position z and the linear motion position z of the output shaft 9 with respect to the first Hall element 11 is 90 degrees.

Next, the output voltage V2 of the second Hall element 12 and the output voltage V3 of the third Hall element 13 will be described.
In FIG. 1, when the output shaft 9 is viewed from above, the right rotation direction is the positive rotation direction, and the direction in which the output shaft 9 moves from the bottom to the top is the positive linear movement direction. The phase of the output voltage V2 is advanced by π / 2 from V1 at the rotational position θ, and the phase of the output voltage V3 of the third Hall element 13 is advanced by π / 2 from V1 at the linear movement position z. Therefore, V2 and V3 are represented by the following expressions (2) and (3), respectively.
V2 = sin (θ + π / 2) · sinz = cos θ · sinz (2)
V3 = sin θ · sin (z + π / 2) = sin θ · cosz (3)

Therefore, the rotational position θ of the output shaft 9 is determined by using the output voltages V1 and V2 of the first and second Hall elements,
θ = tan ⁻¹ (V1 / V2) [rad] (4)
Can be calculated with
The linear movement position z of the output shaft 9 uses the output voltages V1 and V3 of the first and third Hall elements,
z = tan ⁻¹ (V1 / V3) [rad] (5)
Can be calculated with

In the equation (5), the linear motion position z of the output shaft 9 is expressed by an electrical angle.
z ′ = z · L / π [m] (6)
Can be expressed as Here, L represents the magnetic pole pitch [m] of the position detection magnet.

  As described above, in the present invention, the position detecting device 10 and the three Hall elements can be used to detect the rotational position and the linear motion position of the output shaft 9 at the same time. Can be

FIG. 6 is a perspective view showing the arrangement of position detection magnets and Hall elements in a position detection apparatus for a combined rotary and linear motor, showing a second embodiment of the present invention.
In FIG. 6, reference numeral 14 denotes a fourth Hall element. The present embodiment is different from the first embodiment in that the fourth hole is located at a position separated from the position of the second Hall element 12 in the axial direction by a distance 20 that is 1/2 of the magnetic pole pitch 19 of the position detecting magnet 10. The element 14 is added.

By the same calculation as in the first embodiment, the output voltage V4 of the fourth Hall element 14 is expressed by the following equation (7).
V4 = sin (θ + π / 2) · sin (z + π / 2) = cos θ · cosz (7)
The output voltages V1 to V3 of the first to third Hall elements are respectively expressed by the formulas (1) to (3) described in the first embodiment.

  First, the principle of detecting the rotational position θ of the output shaft 9 will be described. When the position detecting magnet 10 rotates, the output voltage V1 of the first hall element 11 is compared with the output voltage V1 of the first hall element 11 by comparing the output voltage V1 of the first hall element 11 and the output voltage V3 of the third hall element 13. When the value is larger, the rotational position θ of the output shaft 9 is calculated using the output voltage V1 of the first Hall element 11 and the output voltage V2 of the second Hall element 12, and the output of the third Hall element 13 is calculated. When the voltage V3 is larger, the rotational position θ of the output shaft is calculated using the output voltage V3 of the third Hall element 13 and the output voltage V4 of the fourth Hall element 14.

That is, it calculates using the following (8) or (9) Formula.
θ = tan ⁻¹ (V1 / V2) (when V1> V3) (8)
θ = tan ⁻¹ (V3 / V4) (when V1 ≦ V3) (9)

Next, the principle of detecting the linear movement position z of the output shaft 9 will be described.
When the output shaft 9 is linearly moved, the output voltage V1 of the first Hall element 11 is compared with the output voltage V2 of the second Hall element 12, and the output voltage V1 of the first Hall element 11 is greater. When it is larger, the linear motion position z of the output shaft 9 is calculated using the output voltage V1 of the first Hall element 11 and the output voltage V3 of the third Hall element 13, and the output voltage of the second Hall element 12 is calculated. When V2 is larger, the linear motion position z of the position detecting magnet 10 is calculated using the output voltage V2 of the second Hall element 12 and the output voltage V4 of the fourth Hall element 14.

That is, it calculates using the following (10) or (11) Formula.
z = tan ⁻¹ (V1 / V3) (when V1> V2) (10)
z = tan ⁻¹ (V2 / V4) (when V1 ≦ V2) (11)

  By calculating the rotational position and the linear motion position of the output shaft 9 as described above, when the linear motion position z varies while the rotational position θ is 180 °, or when the linear motion position z is 180 °, When the rotational position θ fluctuates, the output signal of the first Hall element 11 is always 0 [V], and it can be avoided that position detection becomes difficult.

  In the present invention, the Hall element is used as the position detection element, but other magnetic detection elements such as a magnetoresistance effect element may be used.

Side sectional view of the combined rotary / linear motor of the first embodiment Sectional drawing along the AA line of FIG. 1 is a cross-sectional side view of the position detection device of FIG. The perspective view of the position detection magnet and Hall element in 1st Example Graph of output voltage waveform of first Hall element with respect to rotational position θ and linear motion position z The perspective view of the position detection magnet and Hall element in 2nd Example Side sectional view showing the structure of a position detection device for rotation of a conventional combined rotary / linear motor Side sectional view showing the structure of a position detecting device for linear motion of a conventional combined rotary / linear motion motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor part 2 Position detection apparatus 21 Position detection apparatus for rotation 22 Position detection apparatus for linear motion 3 Linear motion bearing 4 Rotation bearing 5 Rotation signal generation part 6 Rotation signal detector 7 Linear motion signal generation part 8 Linear motion signal detector DESCRIPTION OF SYMBOLS 9 Output shaft 10 Position detection magnet 11 1st hall element 12 2nd hall element 13 3rd hall element 14 4th hall element 15 Magnetization direction 16 Rotary / linear motion bearing 17 Position of (theta) = 0 18 z = 0 position 19 Magnetic pole pitch 20 1/2 of magnetic pole pitch

Claims (6)

A motor unit having an output shaft that moves in a rotational direction and a linear motion direction;
A position detection device for detecting a rotational position and a linear motion position of the output shaft ;
With
The position detecting device is a disc-like shape that is magnetized in one direction in the horizontal direction with respect to the disc-shaped plane, and is arranged at equal intervals with the plane perpendicular to the linear motion direction so that adjacent magnetization directions are reversed from each other. A position detection device for a combined rotary / linear motion motor having a plurality of position detection magnets. The position detection device includes:
A first Hall element disposed via a gap with respect to a circumferential side surface of the position detection magnet;
A second Hall element disposed at a position rotated by 90 degrees in the circumferential direction from the position of the first Hall element;
A third Hall element disposed at a position separated from the position of the first Hall element by a half pitch of the magnetic pole pitch of the position detecting magnet in the linear motion direction ;
With
From the output voltage of the first Hall element and the second hall element, it obtains the rotational position,
Wherein the output voltage of the first Hall element and the third Hall element, obtaining the linear motion position, claim 1 rotation-linear motion composite position detecting apparatus for a motor according. Wherein the rotational position determined by the arctangent calculation of the output voltage of the output voltage and the second Hall element of said first Hall element,
It said linear motion position, the first calculated by arctangent calculation of the output voltage and the output voltage of the third Hall element of the Hall element, according to claim 2 rotation and linear motion composite position detecting apparatus for a motor according. The position detection device includes:
A first Hall element disposed via a gap with respect to a circumferential side surface of the position detection magnet;
A second Hall element disposed at a position rotated by 90 degrees in the circumferential direction from the position of the first Hall element;
A third Hall element disposed at a position separated from the position of the first Hall element by a half pitch of the magnetic pole pitch of the position detecting magnet in the linear motion direction;
A fourth Hall element disposed at a position separated from the position of the second Hall element by a half pitch of the magnetic pole pitch of the position detecting magnet in the linear motion direction ;
With
From the output voltage of the first Hall element and the second Hall element, or the output voltage of the third Hall element and the fourth Hall element , to determine the rotational position,
From the said the first Hall element output voltage of the third Hall element or the output voltage of the second Hall element and the fourth Hall elements, obtaining the linear motion position, and rotation of Claim 1, wherein Position detection device for linear motion combined motor. Wherein the rotational position determined by the arctangent calculation of the first inverse tangent calculation of the Hall element and the output voltage of the second Hall element or the output voltage of the third Hall element and the fourth Hall elements,
The linear motion position determined by the arctangent calculation of the output voltage of said first inverse tangent calculation of the Hall element and the output voltage of the third Hall element or the second Hall element and the fourth Hall elements , claim 4 rotation and linear motion composite position detecting apparatus for a motor according. With a position detecting device of the rotation-linear composite motor according to any one of claims 1 to 4, the rotation-linear composite motor.

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