JP6008806B2 - Magnetic switch device and elevator car position detection apparatus using the same - Google Patents

Description

  The present invention relates to a magnetic switch device that detects the approach and / or passage of a detection object made of a magnetic material in a non-contact manner and an elevator car position detection apparatus using the magnetic switch device.

  For example, Patent Document 1 discloses a magnetic type having a permanent magnet disposed at one end of a U-shaped or C-shaped magnetic frame and a magnetic sensor disposed at the other end of the magnetic frame opposite to the permanent magnet. A position detecting device for detecting whether or not metal plates arranged at a plurality of positions corresponding to stoppage positions at which elevator cars can be stopped are positioned between both ends of a magnetic frame. A type position detector is disclosed.

  Patent Document 2 discloses a magnetic shield made of a highly permeable material such as permalloy (Fe—Ni alloy) and having an opening surface facing an object to be inspected, and a magnetic shield disposed therein. A magnetic substance detection apparatus that includes a sensor and detects magnetic foreign matter mixed in an object to be inspected is disclosed.

WO2008 / 044303 pamphlet (paragraphs [0008] to [0021], FIG. 3) JP 2009-092507 A (paragraphs [0025] to [0039], FIG. 1)

  As described above, the magnetic switch device generally detects a change in magnetic field intensity from a magnetic source such as a permanent magnet or a magnetic foreign object with a magnetic sensor, and changes the magnetic field strength such as a metal plate or a magnetic foreign object. The presence / absence of the magnetic substance to be detected is detected. However, conventional magnetic switch devices change the magnetic field strength (magnetic field distribution) to be detected due to environmental magnetic noise or disturbance magnetic fields other than the magnetic members or magnetic sources existing in the vicinity of the magnetic switch device, so that the magnetic substance to be detected is accurate. Sometimes it was not detected well.

  More specifically, the magnetic position detection device described in Patent Document 1 detects a change in the strength of a magnetic field from a permanent magnet when a metal plate approaches and passes between U-shaped magnetic frames. However, when there is a large magnetic material or environmental magnetic noise (disturbance magnetic field) around the magnetic switch device, the magnetic field intensity detected by the magnetic switch device changes. As a result, there is a problem that it becomes difficult to detect the presence or absence of the metal plate by the magnetic position detection device, and the accuracy of detecting the approach and passage of the elevator car may be reduced.

  In addition, the magnetic substance detection device described in Patent Document 2 is configured to detect a change in the strength of the magnetic field from the magnetic foreign object when the magnetic foreign object mixed in the object to be inspected is at a position facing the opening surface of the magnetic shield. However, when there is an environmental magnetic noise that is not shielded by the magnetic shield, the magnetic field intensity detected by the magnetic substance detection device similarly changes. As a result, in order to suppress environmental magnetic noise as much as possible, it was necessary to employ a magnetic shield having a high cost and a large size.

  Therefore, in Patent Document 1, a U-shaped magnetic frame is configured to surround a permanent magnet and a magnetic sensor, and the size thereof is increased. In Patent Document 2, the magnetic sensor is arranged with respect to the opening surface of the magnetic shield. Measures have been taken to avoid the influence of environmental magnetic noise as much as possible by arranging it at a predetermined angle.

  However, in order to suppress the influence of environmental magnetic noise as much as possible as described above, the size of the U-shaped magnetic frame is increased (Patent Document 1), and the size of the magnetic shield is increased (Patent Document 2). However, there is a problem that the overall size of the magnetic position detection device including the magnetic sensor and the magnetic substance detection device is increased, the installation place thereof is restricted, and the production cost is increased.

  The present invention has been made to solve the above problems, and there has been environmental magnetic noise around the magnetic sensor without adding an expensive magnetic shielding member while maintaining a small size. However, an object of the present invention is to provide a magnetic switch device having high detection accuracy.

A magnetic switch device according to the present invention comprises a magnetic main body portion made of a magnetic material and forming an opening, a permanent magnet disposed at a first end portion of the magnetic main body portion, and a first end portion of the magnetic main body portion. And a magnetic sensor disposed at a second end facing the first. A magnetic circuit passing through the magnetic main body, the magnetic sensor, and the opening is formed by the magnetomotive force F of the permanent magnet, and the magnetic flux density B penetrating the magnetic main body is determined by the magnetic resistance R of the magnetic circuit and the magnetomotive force F of the permanent magnet. and using the cross-sectional area S perpendicular to the magnetic circuit of the magnetic body portion represented by the formula {B = F / (RS) }, wherein the magnetic flux density B is the saturation magnetic flux density B _S or more magnetic body portion It is what.

  According to the present invention, it is possible to avoid an increase in the size of the magnetic switch device, stabilize the magnetic flux density at the position of the magnetic sensor even if there is environmental magnetic noise around the magnetic sensor without incurring the cost of additional members. Therefore, it is possible to provide a magnetic switch device that can detect a detection target with high accuracy.

1 is a perspective view showing a magnetic switch device according to a first embodiment of the present invention. It is a front view which shows the elevator car containing the position detection apparatus using the magnetic switch device which concerns on this invention, and an elevator hoistway. (A) And (b) is the side view which looked at the 1st and 2nd arm part of the magnetic switch device shown in FIG. 1 from the X direction, (c) is a rear view of the base part of a magnetic switch device. is there. (A) And (b) is the top view which looked at the magnetic switch device shown in FIG. 1 from upper direction, Comprising: The change of the magnetic circuit (magnetic flux density B) before and behind arrange | positioning a to-be-detected body in an opening part is shown. Is. (A) And (b) is the side view which looked at the 1st and 2nd arm part from the X direction. It is a perspective view which shows the magnetic switch device which concerns on Embodiment 2 of this invention. (A) And (b) is the side view which looked at the 1st and 2nd arm part shown in FIG. 6 from the X direction, (c) is a rear view of the base part shown in FIG. FIG. 10 is a perspective view showing a magnetic switch device according to Modification 1 of Embodiment 2. It is a rear view of the base part shown in FIG. It is a perspective view which shows the magnetic switch device which concerns on Embodiment 3 of this invention. It is a perspective view which shows the magnetic switch device which concerns on Embodiment 3 of this invention. (A) And (b) is a rear view of the base part which concerns on Embodiment 3. FIG. It is the partial cross section front view which looked at the base part of the magnetic switch device which concerns on the modification 2 of Embodiment 3 from the Y direction. (A)-(c) is a partial cross section front view which shows the other various modifications of the modification 2. FIG. It is the top view which looked at the magnetic switch device concerning Embodiment 4 of this invention from upper direction. It is the top view which looked at the magnetic switch device concerning Embodiment 5 of this invention from upper direction.

  An embodiment of a magnetic switch device according to the present invention and an elevator car position detection apparatus using the same will be described with reference to the accompanying drawings. In the description of each embodiment, terms (for example, “X direction”, “Y direction”, “Z direction”, “vertical direction”, “horizontal direction”, etc.) representing directions are used for easy understanding. Although used where appropriate, this is for illustration purposes only and these terms do not limit the invention.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing a magnetic switch device 1 according to Embodiment 1 of the present invention. FIG. 2 is a front view showing an elevator car 7 including a position detection device 6 using the magnetic switch device 1 and an elevator hoistway 8.

  As shown in FIG. 1, a magnetic switch device 1 according to the present invention is made of a magnetic material, and has a magnetic main body 20 having an opening 10, and a permanent magnet 22 disposed at one end of the magnetic main body 20. And a magnetic sensor 24 disposed at the other end opposite to the one end. Further, although not shown in FIG. 1, the magnetic switch device 1 is an electric circuit board 26 (on which a control circuit for processing the signal from the magnetic sensor 24 to detect the presence or absence of the detected object 50 made of a magnetic material) is mounted. In particular, see FIG. 4A and FIG.

  The magnetic body 20 is not limited to this, but may have a U-shape including the bent portions 28a and 28b, or other shapes (not shown, but not including a bent portion C). Or a V-shape having a single bent portion 28 or the like.

  More specifically, the magnetic main body portion 20 shown in FIG. 1 has first and second arm portions 32 and 34 and a base portion 30 for magnetically coupling them. In the magnetic switch device 1 shown in FIG. 1, the permanent magnet 22 is disposed on the first arm portion 32 so that the north pole faces the first arm portion 32, and the magnetic sensor 24 is disposed on the south pole of the permanent magnet 22. It arrange | positions at the 2nd arm part 34 so that it may oppose. The directions of the N pole and S pole of the permanent magnet 22 may be reversed. The permanent magnet 22 in FIG. 1 forms a magnetic circuit 40 (magnetic flux density B indicated by a thick broken line in FIG. 1) that passes through the magnetic main body 20 and the magnetic sensor 24 by the magnetomotive force F.

  As shown in FIG. 2, the elevator car 7 is generally connected to one end of a plurality of main ropes (main cables) wound around a drive sheave (not shown) provided on the upper part of the elevator hoistway 8. Although not shown, a counterweight is connected to the other end, and the hoisting machine is configured to move up and down by driving the drive sheave.

  The position detection device 6 of the elevator car 7 includes a magnetic switch device 1 according to the present invention, and a detected object (for example, a metal plate) 50 made of a magnetic material installed so as to be able to pass through and stop in the opening 10. Have The elevator car 7 shown in FIG. 2 has the magnetic switch device 1 according to the present invention fixed to its side wall, and a plurality of detected bodies 50 are fixed to positions corresponding to the floors of the side wall of the elevator hoistway 8. Alternatively, the plurality of magnetic switch devices 1 may be fixed at positions corresponding to the floors of the side walls of the elevator hoistway 8 and the detected object 50 may be fixed to the side walls of the elevator car 7.

  The magnetic switch device 1 according to the present invention is shown in FIG. 1 such that the detected object 50 is raised relative to the magnetic switch device 1, and the detected object 50 is indicated by a thin broken line. The magnetic circuit 40 is interrupted when positioned within one opening 10 and the magnetic sensor 24 detects a substantial decrease in the magnetic flux density B, thereby detecting the presence or absence of the detected object 50. That is, the position detection device 6 of the elevator car 7 using the magnetic switch device 1 according to the present invention has the presence or absence (approach or passage) of the detected object 50 fixed at a position corresponding to each floor of the side wall of the elevator hoistway 8. The position of the elevator car 7 is detected.

  Next, a more specific configuration and characteristics of the magnetic switch device 1 according to the first embodiment will be described below. 3 (a) and 3 (b) are side views of the first and second arm portions 32 and 34 of the magnetic switch device 1 of FIG. 1 viewed from the X direction, and FIG. It is the rear view which looked at the base part 30 of the magnetic switch device 1 of FIG. 1 from the reverse direction (-Y direction) with respect to the Y direction. 4A and 4B are plan views of the magnetic switch device 1 of FIG. 1 as viewed from above (−Z direction), before and after the detected object 50 is disposed in the opening 10. The change of the magnetic circuit 40 (magnetic flux density B) is shown.

  In the magnetic switch device 1 according to the present invention, as described above, when the detected object 50 is not disposed in the opening 10 (FIG. 4A), the magnetic circuit 40 (magnetic flux density B) is the magnetic main body 20. And when the detected object 50 is in the opening 10 through the magnetic sensor 24 (FIG. 4B), the magnetic circuit 40 (magnetic flux density B) is a part of the first arm portion 32, the base portion 30, Since the magnetic flux density B detected by the magnetic sensor 24 is extremely small because it passes through the detected object 50, the presence of the detected object 50 can be detected. Note that the electric circuit board 26 is fixed to the second arm portion 34 by using a support member 27, and FIGS. 4A and 4B show the permanent magnet 22 and the electric circuit board for the sake of clarity. 26 is exaggerated and enlarged.

3 and 4, the first and second arm portions 32 and 34 according to the first embodiment have a length l in the Y direction of about 40 mm to about 100 mm, and a height h in the Z direction. It may be about 3 mm to about 10 mm (FIGS. 3A and 3B), and the thickness d in the Y direction may be about 1 mm to about 2 mm (FIG. 4A). Base unit 30 according to the first embodiment, similarly, the length _{l 0} of the X-direction is about 40 to about 100 mm, the height _{h 0} of about 3 to about 10mm in the Z direction (FIG. 3 (c )), The thickness d in the Y direction may be about 1 mm to about 2 mm as in the first and second arm portions 32 and 34. Further, the dimension in the Z direction of the permanent magnet 22 indicated by a broken line in FIG. 3A may not exceed the height h of the first arm portion 32.

  However, the permanent magnet 22 preferably has a higher surface area parallel to the YZ plane to form a higher magnetic flux density B, as will be described in detail later. 5 (a) and 5 (b) are side views of the first and second arm portions 32 and 34 as seen from the X direction, and are the same as FIGS. 3 (a) and 3 (b). Is. The first arm portion 32 in FIG. 5A has a magnet support portion 33 made of a magnetic material at the tip portion. The first arm portion 32 and the magnet support portion 33 may be formed individually and then joined, but are preferably integrally formed. The length l ′ in the Y direction and the height h ′ in the Z direction of the magnet support 33 shown in FIG. 5A and the permanent magnet 22 fixed to the magnet support 33 are approximately the same in the range of about 10 mm to about 30 mm. It may be present (FIG. 5 (a)). Similarly, the length in the Y direction and the height in the Z direction of the electric circuit board 26 facing the permanent magnet 22 are approximately the same as the length l ′ in the Y direction and the height h ′ in the Z direction of the permanent magnet 22. It may be present (FIG. 5B).

That is, in the first embodiment, the base portion 30 and the first and second arm portions 32 and 34 of the magnetic main body portion 20 are dimensioned in the X direction, the Y direction, and the Z direction (especially on a plane orthogonal to the magnetic circuit 40). Parallel sectional areas S ₀ , S ₁ , S ₂ ) are configured to be substantially the same.

The cross-sectional area S ₀ parallel to the YZ plane orthogonal to the magnetic circuit 40 of the base portion 30 and the cross-sectional area S ₁ parallel to the XZ plane orthogonal to the magnetic circuit 40 of the first and second arm portions 32 and 34 are also shown. , _{S 2} is (Fig. 1), may be designed to be smaller than the cross-sectional area _{S 3} parallel to the YZ plane perpendicular to the magnetic circuit 40 of the magnet support portion 33 (Figure 5 (a)). In addition, the dimension of each direction of the permanent magnet 22, the U-shaped magnetic main body 20, the electric circuit board 26, and the magnetic sensor 24 is not limited to the above specific example, and further, if necessary, the base portion The length (l ₀ , l), the height (h ₀ , h), and the thickness (d) in the Y direction between the 30 and the first and second arm portions 32 and 34 may be designed to be different. .

  In the first embodiment, the permanent magnet 22 is a ferrite magnet, and the U-shaped magnetic main body portion 20 is made of a soft magnetic material such as iron or an iron-based alloy (for example, a cold-rolled steel plate). The magnetic sensor 24 may be a Hall element.

  The permanent magnet 22 may be an arbitrary magnet having a higher magnetomotive force F such as a neodymium magnet, a samarium cobalt magnet, and a plastic magnet including these materials, in addition to a ferrite magnet.

  The magnetic body 20 (the base 30 and the first and second arms 32 and 34) and the magnet support 33 are made of magnetism such as iron, nickel, permalloy (Fe—Ni alloy), or silicon steel plate (silicon steel). You may produce using a material. Similarly, the object to be detected 50 may be made of a magnetic material such as nickel, permalloy (Fe—Ni alloy), or silicon steel plate (silicon steel) in addition to iron or an iron-based alloy.

  In addition to the Hall element, the magnetic sensor 24 includes an AMR sensor (anisotropic magnetoresistive sensor), a GMR sensor (giant magnetoresistive sensor, TMR sensor (tunnel magnetoresistive sensor), FG sensor (fluxgate sensor), and MI sensor (magnetic). Any magnetic sensor capable of detecting a change in the magnetic flux density B such as an impedance sensor can be used.

  As described above, most of the lines of magnetic force generated by the magnetomotive force F of the permanent magnet 22 pass through the permanent magnet 22, the U-shaped magnetic main body 20, and the magnetic sensor 24 as shown by the thick broken line in FIG. A magnetic circuit 40 is formed. In the magnetic switch device 1 configured as described above, when the detected object 50 passes through the opening 10 of the magnetic main body 20, that is, between the permanent magnet 22 and the magnetic sensor 24, the magnetic circuit 40 is cut off, and the magnetic flux The change of the density B can be detected by the magnetic sensor 24, and the approach or passage of the detection target 50 can be detected.

  By the way, in the general magnetic switch device 1, since the magnetic sensor 24 detects the change in the intensity of the surrounding magnetic field and detects the approach or passage of the detected object 50, a large magnetic body is formed around the magnetic switch device 1. If there is a disturbance magnetic field, the surrounding magnetic field is disturbed, and the magnetic flux density B passing through the magnetic sensor 24 changes, which may adversely affect the detection accuracy of the approaching and passing of the detected object 50.

  Therefore, the conventional magnetic switch device increases the size of the U-shaped magnetic main body 20 (particularly, the size of the second arm 34 in the Y direction and Z direction) to substantially cover the magnetic sensor 24, The disturbance magnetic field caused by other than the magnetomotive force F of the permanent magnet 22 is configured to be cut off or effectively reduced.

  However, although depending on the distance between the magnetic sensor 24 and the magnetic main body portion 20 (second arm portion 34), the dimension of the U-shaped magnetic main body portion 20 (particularly the height dimension in the Z direction) is large. Although the shielding effect of the disturbance magnetic field with respect to the magnetic sensor 24 is improved, in order to sufficiently shield the disturbance magnetic field, the dimensions of the magnetic main body 20 (second arm portion 34) in the Y direction and the Z direction are at least about. It was necessary to design to 40 mm or more.

  In the conventional magnetic switch device 1, a disturbance magnetic field shielding member (not shown) separate from the magnetic main body 20 is additionally arranged around the magnetic main body 20 including the magnetic sensor 24. Measures have been taken to shield or reduce the disturbing magnetic field around the magnetic sensor 24.

  However, when the size of the magnetic main body 20 is increased or a disturbance magnetic field shielding member separate from the magnetic main body 20 is provided, the overall size of the magnetic switch device 1 is increased. For example, the fixed position on the side wall of the elevator car 7 There is a problem that the manufacturing cost of the magnetic switch device 1 is increased.

Therefore, the magnetic switch device 1 according to the present invention will be described in detail below. The magnetomotive force F of the permanent magnet 22, the cross-sectional area S orthogonal to the magnetic circuit 40 of the magnetic body 20, and the magnetic resistance R of the magnetic circuit 40 are parameters. As described above, the magnetic flux density B on the magnetic circuit 40 is calculated (estimated), and the calculated magnetic flux density B is configured to be _{equal to} or higher than the saturation magnetic flux density BS of the magnetic main body 20 itself. By magnetic saturation, the influence of the disturbance magnetic field on the magnetic flux density B on the magnetic circuit 40 is avoided or suppressed to a minimum, and the detected object 50 is detected with high accuracy by the magnetic sensor 24.

  As shown in FIG. 1, the magnetic circuit 40 (magnetic flux density B) is generally circulated through the permanent magnet 22, the magnetic body 20, the magnetic sensor 24, and the opening 10 by the magnetomotive force F of the permanent magnet 22. Formed and having a magnetoresistance R.

The magnetic switch device 1 shown in FIG. 1 and FIGS. 3A to 3C has a cross-sectional area S of the magnetic body portion 20, that is, a cross-sectional area S _{0 of the} base portion 30 and the first and second arm portions 32 and 34. , S ₁ , S ₂ are reduced to increase the magnetic flux density B on the magnetic circuit 40 and magnetically saturate the magnetic body 20.

  Further, the magnetic flux density B on the magnetic circuit 40 may be increased by using the permanent magnet 22 having a large magnetomotive force F. Instead of the ferrite magnet used as the permanent magnet 22, a magnetic flux density B on the magnetic circuit 40 may be increased by using a neodymium magnet or a samarium cobalt magnet having a larger magnetomotive force F.

Further, as shown in FIG. 5 (a), the permanent magnet 22, by replacing the larger dimension (cross-sectional area S ₃ or X direction thickness) Gayori perpendicular to the magnetic circuit 40, the magnetic circuit 40 on The magnetic flux density B may be increased. Since the magnetomotive force F of the permanent magnet 22 is increased substantially in proportion to the X dimension of the permanent magnet 22, rather than increasing the cross-sectional area S ₃ of the permanent magnet 22, the X dimension of the permanent magnet 22 Increasing the thickness can increase the magnetic flux density B on the magnetic circuit 40 more efficiently.

  Further, the magnetic switch device 1 according to the first embodiment increases the magnetic flux density B on the magnetic circuit 40 by decreasing the magnetic resistance R of the magnetic circuit 40, thereby magnetically saturating the magnetic main body 20 and magnetically You may comprise so that the influence by the disturbance magnetic field with respect to the magnetic flux density B on the circuit 40 may be avoided or suppressed to the minimum.

For example by minimizing the distance of the opening 10 between the base portion 30 in the X direction length l ₀ and the permanent magnet 22 and the electric circuit board 26, by increasing the magnetic flux density B of the magnetic circuit 40, magnetic The main body 20 may be magnetically saturated. However, when the magnetic switch device 1 is used as a position detecting device for an elevator car, the detected object 50 contacts the permanent magnet 22 or the electric circuit board 26 in consideration of the thickness of the detected object 50 and the swing of the main rope 9. It is necessary to design the opening 10 so that it does not occur.

  Moreover, you may comprise so that the magnetic resistance R of the magnetic circuit 40 may be made small by immersing the magnetic switch device 1 in a magnetic fluid, and filling the opening part 10 with a magnetic fluid. As described above, by reducing the distance of the opening 10 between the permanent magnet 22 and the electric circuit board 26 as much as possible, or by filling the opening 10 with magnetic fluid, the magnetic resistance R of the magnetic circuit 40 is reduced, The magnetic main body 20 can be magnetically saturated so that the influence of the disturbance magnetic field on the magnetic flux density B on the magnetic circuit 40 can be avoided or minimized. As a result, the magnetic switch device 1 according to the present invention can detect the detection target 50 with high accuracy.

In summary, according to the present invention, the means using the permanent magnet 22 having a large magnetomotive force F, the means for reducing the cross-sectional area S orthogonal to the magnetic circuit 40 of the magnetic body 20, and the magnetic resistance R of the magnetic circuit 40 are reduced. By adopting at least one of the means for performing magnetic saturation, the magnetic main body 20 is magnetically saturated and calculated from the magnetomotive force F of the permanent magnet 22, the cross-sectional area S of the magnetic main body 20, and the magnetic resistance R of the magnetic circuit 40. increasing the magnetic flux density B of the magnetic circuit 40 that is to saturation magnetic flux density B ₀ of the magnetic body portion 20, due to the disturbance magnetic field, it is the magnetic flux density B is substantially eliminated to increase more.

That is, when the magnetic main body 20 is in a magnetic saturation state, the magnetic flux density B of the magnetic circuit 40 that passes through the permanent magnet 22, the U-shaped magnetic main body 20, the magnetic sensor 24, and the opening is hardly affected by the disturbance magnetic field. stabilizes at a substantially constant saturation magnetic flux density B _0.

Therefore, according to the first embodiment of the present invention, even if a disturbance magnetic field is generated around the magnetic main body 20, a stable magnetic flux density B (in the magnetic sensor 24 is used without using a separate disturbance magnetic field shielding member. Since the saturation magnetic flux density B ₀ ) can be supplied, the small magnetic switch device 1 that can detect the detection target 50 with high reliability can be provided.

  The generation source of the disturbance magnetic field includes, for example, a magnet or a magnetic material, a coil through which a large current flows, power supply wiring, and the like. The magnetic field strength of the disturbance magnetic field also varies depending on the magnetomotive force F of the permanent magnet 22 and the size of the magnetic main body 20, the amount of current flowing through the coil or the power supply wiring, and also varies greatly depending on the distance from the source of the disturbance magnetic field.

  Next, as described above, the magnetic flux density B on the magnetic circuit 40 is set by using the magnetomotive force F of the permanent magnet 22, the cross-sectional area S orthogonal to the magnetic circuit 40 of the magnetic main body 20, and the magnetic resistance R of the magnetic circuit 40 as parameters. A calculation formula for calculating (estimating) will be described below.

In the magnetic switch device 1 according to the first embodiment, the amount of change in the magnetic flux density detected by the magnetic sensor 24 depending on the presence or absence of the detection target 50 is several millimeters to several tens of millimeters (on the order of 10 ⁻³ T to 10 ⁻² T). If the U-shaped magnetic main body 20 is omitted, it can be affected by a disturbance magnetic field of several millitesla (on the order of 10 ⁻³ T).

In general, the total magnetic flux φ of the magnetic circuit 40 is expressed by the following equation using the magnetic resistance R of the magnetic circuit 40 and the magnetomotive force F of the permanent magnet 22.
[Equation 1]
φ = F / R (1)

Assuming that most of the magnetic flux φ of the magnetic circuit 40 passes through the magnetic main body 20, the magnetic flux φ is expressed by the following equation using the cross-sectional area S of the magnetic main body 20 and the magnetic flux density B penetrating the magnetic main body 20. Is done.
[Equation 2]
φ = BS (2)

From the above equations (1) and (2), the following equation is derived.
[Equation 3]
B = F / (RS) (3)

On the other hand, when the magnetic body portion 20 is magnetically saturated, the magnetic flux density B is a saturated magnetic flux density B _S above, the following equation holds.
[Equation 4]
B = F / (RS) ≧ Bs (4)

Therefore, according to the present invention, the magnetic flux density B on the magnetic circuit 40 is increased with the magnetomotive force F of the permanent magnet 22, the cross-sectional area S orthogonal to the magnetic circuit 40 of the magnetic body 20, and the magnetic resistance R of the magnetic circuit 40 as parameters. formula calculated by (4), (causing the magnetic body portion 20 is magnetically saturated) was calculated magnetic flux density B is configured such that the saturation magnetic flux density B _S or more magnetic body portion 20. As a result, the present invention can avoid or minimize the influence of the disturbance magnetic field on the magnetic flux density B on the magnetic circuit 40 and can detect the detected object 50 with high accuracy by the magnetic sensor 24.

The magnetomotive force F of the permanent magnet 22 can be simply calculated by the following equation using the coercive force Hc of the permanent magnet 22 and the magnet length lm (FIG. 4A).
[Equation 5]
F = Hc · lm (5)

In addition, since it is difficult to directly obtain the magnetic resistance R, in general, the permeance coefficient P, which is the reciprocal thereof, is orthogonal to the magnetic permeability μ of the magnetic circuit 40, the length L of the magnetic circuit 40, and the magnetic circuit 40. Using the cross-sectional area S of the magnetic body 20, the following equation is used.
[Equation 6]
R ⁻¹ = P = (μS) / L (6)

Therefore, the magnetic flux density B on the magnetic circuit 40 can be expressed by the following equation using the above equation (5) and the above equation (6).
[Equation 7]
B = F / (RS)
= (FP) / S = μ · Hc · lm / L (7)

The smaller the cross-sectional area S perpendicular to the magnetic circuit 40 of the magnetic body 20 is, the easier it is to satisfy the above equation (4). However, as shown in FIG. 3A, the cross-sectional area S ₃ of the permanent magnet 22 is not necessarily smaller. do not have to. Further, as shown in FIG. 5 (a), the sectional area S of the magnetic body portion 20 in both the Y and Z directions may be larger than the cross-sectional area S ₃ of the permanent magnet 22. In either case of FIG. 3 (a) and FIG. 5 (a), the cross-sectional area S (S ₀ , S ₁ , S ₂ ) of the magnetic main body 20 and the permanent magnet as long as the above formula (4) is satisfied. It may be arbitrarily selected as the cross-sectional area S ₃ of 22.

  Further, in order to satisfy the above formula (4), as described above, the permanent magnet 22 having a large magnetomotive force F may be adopted, or the magnetic switch device 1 is arranged so as to reduce the magnetic resistance R of the magnetic circuit 40. It may be configured.

An exemplary embodiment that satisfies the above equation (4) will now be described. For example, the coercive force Hc of 250 [kA / m] and the magnetomotive force F of a ferrite magnet having a magnet length lm of 1 centimeter can be calculated using the above equation (5).
[Equation 8]
Hc = 250 [kA / m] = 2.5 × 10 ⁵ [A / m]
lm = 1 [cm] = 0.01 [m]
∴F = 2.5 × 10 ³ [A] (8)

Further, the relative permeability μ (= μ / μ ₀ ) of the entire magnetic circuit 40 is set to 100, the cross-sectional area S of the magnetic main body 20 is set to 3 [mm] × 3 [mm], and the length L of the magnetic circuit 40 is set to Assuming 10 [cm], the permeance coefficient P can be calculated using the above equation (5).
[Equation 9]
μ = 100 × 4π × 10 ⁻⁷ [H / m]
S = 3 × 3 [mm ² ] = 9 × 10 ⁻⁶ [m ² ]
L = 10 [cm] = 0.1 [m]
∴P = 1.1 × 10 ⁻⁸ [H] (9)

Therefore, the magnetic flux density B on the magnetic circuit 40 can be estimated as follows using the above equation (7).
[Equation 10]
B = F / (RS) = (FP) / S
= 2.5 × 10 ⁵ × 1.1 × 10 ⁻⁸ / 9 × 10 ⁻⁶
≒ 3 [T]

  Since the saturation magnetic flux density Bs of iron generally used as the magnetic main body 20 is about 1.5 to 2 [T], the coercive force Hc and the magnet length lm of the permanent magnet 22 and the relative permeability μ of the magnetic circuit 40. When the above condition is satisfied for the cross-sectional area S of the magnetic main body 20 and the length L of the magnetic circuit 40, the above equation [4] is satisfied and the magnetic main body 20 can be magnetically saturated. Therefore, the magnetic switch device 1 according to the present invention can detect the detection target 50 with high reliability while being small in size.

  In the above specific example, it is assumed that most of the magnetic flux φ of the magnetic circuit 40 passes through the magnetic main body 20, and then the magnetic flux density B on the magnetic circuit 40 is calculated by a simple calculation method. It was determined whether 20 could be magnetically saturated. However, actually, the magnetomotive force F of the permanent magnet 22 also depends on the shape and form thereof, and the relative permeability μ of the magnetic circuit 40 and the cross-sectional area S of the magnetic main body 20 are not necessarily constant along the magnetic circuit 40. Therefore, an error may be included in the magnetic flux density B calculated using the above-described simple calculation method. Therefore, it is preferable to calculate the magnetic flux density B more precisely by using a magnetic field analysis technique such as a finite element method.

As described above, according to the present invention, the magnetic flux density B is calculated using the magnetomotive force F of the permanent magnet 22, the cross-sectional area S of the magnetic body 20, and the magnetic resistance R of the magnetic circuit 40 as parameters, and the calculated magnetic flux density. by B is configured such that the magnetic body portion 20 itself saturation magnetic flux density B _S above, to suppress avoid or minimize the effect of a disturbance magnetic field for the magnetic flux density B, to detect accurately the detected body 50 Thus, a small and inexpensive magnetic switch device 1 can be provided.

  The magnetic switch device 1 according to the present invention has been described above as being adopted as the position detecting device 6 of the elevator car 7. However, the present invention is not limited to this. For example, a workpiece in a factory automation device (FA device) It can be applied to any position detection device 6 that detects the presence or absence of the detected object 50, such as a workpiece position detection device that monitors and detects the position of the detected object.

  When the magnetic switch device 1 according to the present invention is used as the position detecting device 6 of the elevator car 7, the cross-sectional area S of the magnetic main body 20 is sufficiently durable to resist vibrations caused by the swing of the main rope 9 and wind pressure. Must be determined to have strength. In this case, similarly, when the detected object 50 moves relative to the magnetic switch device 1, the size of the opening 10 is set so as not to collide with the permanent magnet 22 and the electric circuit board 26 (including the magnetic sensor 24). It is necessary to decide. For example, in the magnetic switch device 1 according to the first embodiment, the dimension between the permanent magnet 22 and the electric circuit board 26 may be set to about 20 mm to about 24 mm.

Embodiment 2. FIG.
A second embodiment of the magnetic switch device according to the present invention will be described in detail below with reference to FIGS. The magnetic switch device 2 according to the second embodiment is a magnetic switch according to the first embodiment, except that a part of the magnetic main body 20 (base portion 30) is configured to have a small height in the Z direction. Since the configuration is the same as that of the device 1, the description of the overlapping contents is omitted.

  FIG. 6 is a perspective view similar to FIG. 1 showing a magnetic switch device 2 according to Embodiment 2 of the present invention. 7 (a) and 7 (b) are side views similar to FIGS. 3 (a) and 3 (b) in which the first and second arm portions 32 and 34 shown in FIG. 6 are viewed from the X direction. FIG. 7C is a rear view similar to FIG. 3C in which the base portion 30 shown in FIG. 6 is viewed from the direction opposite to the Y direction (−Y direction). The first and second arm portions 32 and 34 according to the second embodiment have a larger surface area parallel to the YZ plane than that of the first embodiment, and are larger than the surface areas parallel to the YZ plane of the permanent magnet 22 and the magnetic sensor 24. It is configured to be sufficiently large.

On the other hand, the base portion 30 according to the second embodiment has a narrowed portion 36 that is narrower than the first and second arm portions 32 and 34 (that is, the cross-sectional area perpendicular to the magnetic circuit 40 is smaller). The narrowed portion 36 extends over part or the whole of the base portion 30 and is configured so that the cross-sectional area S of the narrowed portion 36 of the magnetic main body portion 20 becomes smaller. Therefore, the magnetic flux calculated by the above equation [4] It becomes easy to control the density B to be _{equal to} or higher than the saturation magnetic flux density BS. That is, according to the invention according to the second embodiment, the magnetic main body portion 20 is configured so that the constriction portion 36 of the base portion 30 is likely to be magnetically saturated, thereby suppressing the influence by the disturbance magnetic field and the magnetic flux of the magnetic circuit 40. The magnetic switch device 2 which can stabilize the density B and can detect the detection target 50 with high accuracy can be provided.

In the above description, the narrower narrow portion 36 (having a smaller cross-sectional area) has been described as being provided in the base portion 30, but may be provided in the first or second arm portions 32, 34. Preferably, by providing the narrowed portion 36 in the second arm portion 34 where the magnetic sensor 24 is disposed, the second arm portion 34 is magnetically saturated so that the influence of the disturbance magnetic field received by the magnetic sensor 24 is reduced. can do. That is, in the magnetic switch device 2 according to the second embodiment, the narrowed portion 36 is provided in a part or the whole of the base portion 30 and the first and second arm portions 32 and 34, and penetrates the narrowed portion 36. The magnetic flux density B is expressed by the following equation using its cross-sectional area (S ₀ , S ₁ , or S ₂ ), magnetomotive force F, and magnetic resistance R, and at least one of these is the total magnetic body 20 are those configured such that the saturation magnetic flux density B _S above.
[Formula 4 ']
B = F / (RS ₀ ) ≧ Bs
B = F / (RS ₁ ) ≧ Bs
B = F / (RS ₂ ) ≧ Bs (4 ′)

  Therefore, according to the invention according to the second embodiment, as in the first embodiment, the influence of the disturbance magnetic field on the magnetic flux density B can be avoided or suppressed to a minimum, and the small object capable of detecting the detected object 50 with high accuracy. And an inexpensive magnetic switch device 2 can be provided.

  In addition, the magnetic switch device 2 shown in FIGS. 7A and 7B has a surface area parallel to the YZ plane of the first and second arm portions 32, 34, a permanent magnet 22 and a magnetic sensor 24. The magnetic body portion 20 is configured to be sufficiently larger than the surface area parallel to the YZ plane of the magnetic body portion 20 by suppressing the magnetic flux generated by the magnetomotive force F of the permanent magnet 22 from passing through a space other than the magnetic body portion 20. The magnetic flux passing through can be increased. That is, the magnetic flux density B penetrating through the constricted portion 36 can be increased, and the constricted portion 36 of the magnetic main body 20 is likely to be magnetically saturated. Therefore, the influence of the disturbance magnetic field on the magnetic flux density B can be further suppressed, and the detected object 50 can be detected with higher accuracy.

  In the above description, the cross-sectional shape of the narrowed portion 36 has a rectangular shape, but is not limited to this, and may have an arbitrary shape such as a circle, an ellipse, or a polygon. .

(Modification 1)
Although the magnetic switch device 2 shown in FIG. 6 has been described as having a single constriction 36, it may have a plurality of constrictions 36. FIG. 8 is a perspective view similar to FIG. 6 showing the magnetic switch device 2 according to the first modification. FIG. 9 is a rear view similar to FIG. 7C, in which the base portion 30 shown in FIG. 8 is viewed from the direction opposite to the Y direction (−Y direction). That is, the base portion 30 according to the first modification has two narrowed portions 36a and 36b extending in the X direction and spaced apart from each other, and a through window 38 is provided therebetween.

In this case two constrictions 36a, when the sum S ₀ of 36b sectional area that satisfies the above equation (4 '), it is possible to achieve the same effect as the invention according to the second embodiment. Furthermore, according to the first modification, since the first and second arm portions 32 and 34 are connected by the two narrowed portions 36a and 36b, a robust and durable magnetic switch device 2 can be provided.

Embodiment 3 FIG.
A third embodiment of the magnetic switch device according to the present invention will be described in detail below with reference to FIGS. The magnetic switch device 3 according to the third embodiment is implemented except that a through hole 44 or a protrusion 45 through which a fixing means 42 such as a screw for attaching the magnetic main body 20 to the support structure 52 is provided is provided. Since the configuration is the same as that of the magnetic switch device 2 according to the second embodiment, the description of the overlapping contents is omitted.

  10 and 11 are perspective views similar to FIGS. 6 and 8 showing the magnetic switch device 3 according to the third embodiment. 12 (a) and 12 (b) are rear views similar to FIG. 7 (c) when the base portion 30 shown in FIGS. 7 (c) and 9 is viewed from the direction opposite to the Y direction (−Y direction). FIG. As shown in FIGS. 10 to 12, the base portion 30 according to the third embodiment is penetrated through a fixing means 42 such as a fixing screw for attaching the magnetic main body portion 20 to the support structure 52 as described above. A hole 44 is provided. Here, the support structure 52 may be a side wall of the elevator car 7 or the elevator hoistway 8 or a housing (not shown) of the magnetic switch device 3.

  In the through hole 44 according to the third embodiment, as shown in the drawing, the through hole 44 is a region away from a region through which most of the magnetic flux passes so as not to hinder the flow of the magnetic flux on the magnetic circuit 40, that is, It is preferably formed in a region away from the extended region of the narrowed portion 36 extending in the X direction.

  The shape of the through hole 44 shown in FIGS. 12 (a) and 12 (b) is illustrated as having a semicircular shape at both ends and a linear oval shape between the two, but it is oval or rectangular. You may have other arbitrary shapes, such as a shape. However, in order to easily adjust the mounting position of the magnetic switch device 3 with respect to the support structure 52, it is preferable that the shape of the through hole 44 is not a circular shape but an elliptical shape as illustrated.

(Modification 2)
Although the magnetic switch device 3 according to the third embodiment has been described as having the through hole 44, the magnetic main body 20 is attached to the support structure 52 by using a fixing means 42 such as a screw without being limited thereto. May have an arbitrary structure. FIG. 13 is a partial cross-sectional front view of the base portion 30 of the magnetic switch device 3 shown in FIG. 6 as viewed from the Y direction. The narrowed portion 36 of the base portion 30 shown in FIG. 13 has a pair of protruding portions 45 that protrude in parallel with each other in the Z direction and the opposite direction (−Z direction). The pair of projecting portions 45 are preferably formed integrally with the narrowed portion 36 of the base portion 30 in order to manufacture at a low cost. A pair of (two) fixing screws 42 having a screw diameter smaller than the distance between the pair of projecting portions 45 and having a screw head larger than the distance between the pair of projecting portions 45 are inserted between the pair of projecting portions 45 and screwed. The magnetic main body 20 including the portion 30 can be fixed to a support structure 52 such as a housing.

  In order to fix the magnetic main body portion 20 to the support structure 52, the protruding portion 45 through which the fixing screw 42 is inserted is not limited to the above configuration, and FIGS. 14 (a) to 14 (c) It is a partial cross section front view similar to FIG. 13 which shows various modifications. The pair of protrusions 45 shown in FIG. 14A are configured to extend longer in the Z direction and the −Z direction than those shown in FIG. 13, and two pairs (four) of fixing screws 42 are connected to the pair of protrusion screws 45. The magnetic main body 20 including the base portion 30 is more securely fixed to the support structure 52 such as a housing by being inserted between the protruding portions 45 and screwed.

  The narrowed portion 36 of the base portion 30 shown in FIG. 14B has three projecting portions 45 extending in parallel with each other in the Z direction and the −Z direction, and four pairs (eight) of fixing screws 42 are adjacent to each other. The magnetic main body portion 20 including the base portion 30 is more securely fixed to the support structure 52 such as a housing by being inserted between the portions 45 and screwed.

  Alternatively, the base portion 30 shown in FIG. 14C has four pairs of projecting portions 45 extending in parallel with each other in the X direction and the −X direction from portions other than the constricted portion 36, and four fixed portions. The magnetic main body 20 including the base portion 30 is fixed to a support structure 52 such as a housing in a wider area by inserting the screws 42 between the adjacent projecting portions 45 and screwing them. Note that the configuration and form of the protrusion 45 and the fixing screw 42 for fixing the magnetic main body 20 to the support structure 52 are not limited to those described above, and any configuration conceived by those skilled in the art. And forms can be adopted. For example, the through-hole 44 or the protruding portion 45 is provided not in the base portion 30 but in any one of the first and second arm portions 32 and 34, and the −X direction (see FIG. You may attach to support structure 52, such as a housing | casing extended to 2).

  Since the through hole 44 and the protrusion 45 described in the third embodiment are located away from the magnetic circuit 40 and do not hinder or disturb the flow of the magnetic flux density B, the detection accuracy of the magnetic switch device 3 is adversely affected. It does not affect. Further, by providing the through hole 44 or the protrusion 45, the magnetic switch device 3 can be easily attached to the support structure 52 such as a housing.

  Furthermore, according to the invention according to the third embodiment, as in the first and second embodiments described above, the dimensions remain small and are not affected by the disturbance magnetic field, and are stably detected with high reliability. The magnetic switch device 3 that can detect the body 50 can be realized.

Embodiment 4 FIG.
With reference to FIG. 15, Embodiment 4 of the magnetic switch device according to the present invention will be described in detail below. The magnetic switch device 4 according to the fourth embodiment has the magnetic switch device 1 according to the first to third embodiments except that the second arm portion 34 has an arm protrusion 46 at a position facing the magnetic sensor 24. Since it has the same configuration as that of ˜3, the description of the overlapping contents is omitted.

  FIG. 15 is a plan view similar to FIG. 4A in which the magnetic switch device 4 according to Embodiment 4 is viewed from above (−Z direction). As described above, the magnetic switch device 4 has the arm protrusion 46 that faces the magnetic sensor 24 at the tip of the second arm 34. As a result, the magnetic flux directed toward the permanent magnet 22 from the second arm portion 34 of the magnetic main body portion 20 tends to be gradually dispersed in the direction other than the −Y direction in the opening portion 10, so that the magnetic sensor 24 receives the magnetic flux. The magnetic flux density may be smaller than the magnetic flux density B passing through the magnetic main body 20.

  Therefore, in the magnetic switch device 4 according to the fourth embodiment, an arm protrusion 46 facing the magnetic sensor 24 is provided on the second arm 34. At this time, most of the magnetic flux density B passing through the magnetic body 20 is detected by the magnetic sensor 24, and the detection accuracy of the magnetic switch device 4 is improved by increasing the amount of change in the magnetic flux density due to the presence or absence of the detected object 50. In addition, the influence on the disturbance magnetic field can be further reduced, and the detection stability of the detection target 50 can be further improved.

Embodiment 5. FIG.
A magnetic switch device according to a fifth embodiment of the present invention will be described in detail below with reference to FIG. In the magnetic switch device 5 according to the fifth embodiment, the base 30 has a base protrusion 48 extending toward the opening 10, and the detection target 50 disposed in the opening 10 faces the base protrusion 48. Since it has the same configuration as the magnetic switch devices 1 to 4 according to Embodiments 1 to 4 except for the points configured as described above, the description of the overlapping contents is omitted.

  FIG. 16 is a plan view similar to FIG. 4A in which the magnetic switch device 5 according to the fifth embodiment is viewed from above (−Z direction). As described above, in the magnetic switch device 5, the base portion 30 has the base protrusion 48 extending toward the opening 10 (−Y direction), and the detection target 50 arranged in the opening 10 is the base protrusion. 48 so as to face 48. In general, when the detected object 50 is positioned in the opening 10, the magnetic flux generated by the magnetomotive force F of the permanent magnet 22 passes through the first arm part 32, a part of the base part 30, and the detected object 50. According to the fifth embodiment, by providing the base protrusion 48, the magnetic flux flowing from the base 30 to the detected object 50 is increased, and conversely, the magnetic flux reaching the magnetic sensor 24 is decreased, The amount of change in magnetic flux density due to the presence or absence of the detector 50 can be increased. Thus, the magnetic switch device 5 can improve the detection accuracy of the magnetic switch device 5, reduce the influence on the disturbance magnetic field, and further improve the detection stability of the detection target 50.

DESCRIPTION OF SYMBOLS 1-5 ... Magnetic switch device, 6 ... Position detection apparatus, 7 ... Elevator car, 8 ... Elevator hoistway, 9 ... Main rope (main cable), 10 ... Opening part, 20 ... Magnetic main-body part, 22 ... Permanent magnet, 24 ... Magnetic sensor, 26 ... Electric circuit board, 27 ... Strut member, 28 ... Bent part, 30 ... Base part, 32 ... First arm part, 33 ... Magnet support part, 34 ... Second arm part, 36 ... Narrowed portion, 38 ... penetrating window, 40 ... magnetic circuit (magnetic flux density B), 42 ... fixing means (fixing screw), 44 ... through hole, 45 ... projecting portion, 46 ... arm projecting portion, 48 ... base projecting portion, 50 ... detected object, 52 ... support structure, R ... magnetic resistance of magnetic circuit, S ... cross-sectional area of magnetic main body, B _S ... saturation magnetic flux density of magnetic main body.

Claims (8)

A magnetic body made of a magnetic material and forming an opening;
A permanent magnet disposed at a first end of the magnetic body;
A magnetic sensor disposed at a second end facing the first end of the magnetic body,
A magnetic circuit passing through the magnetic main body, the magnetic sensor, and the opening is formed by the magnetomotive force F of the permanent magnet.
The magnetic flux density B penetrating the magnetic main body is expressed by the following equation using a magnetic resistance R of the magnetic circuit, a magnetomotive force F of the permanent magnet, and a cross-sectional area S orthogonal to the magnetic circuit of the magnetic main body. The magnetic switch device is characterized in that the magnetic flux density B is _{equal to} or higher than the saturation magnetic flux density BS of the magnetic main body.
[Equation 1]
B = F / (RS) ≧ Bs The magnetic main body has first and second arm portions and a base portion for magnetically coupling them, and forms the opening between the first and second arm portions,
The magnetic flux density B penetrating the base portion and the first and second arm portions is the cross-sectional areas S ₀ , S ₁ , S _{2 in} the direction perpendicular to the magnetic circuit, the magnetomotive force F, and the magnetic force 2. The magnetic switch device according to claim 1, wherein the magnetic switch device is calculated by the following equation using a resistance R, and at least one of the magnetic flux densities B is equal to or higher than a saturation magnetic flux density B _S.
[Equation 2]
B = F / (RS ₀ ) ≧ Bs
B = F / (RS ₁ ) ≧ Bs
B = F / (RS ₂ ) ≧ Bs 3. The magnetic switch according to claim 2, wherein a cross-sectional area S ₀ of the base portion is smaller than cross-sectional areas S ₁ and S _{2 of} the first and second arm portions in a direction perpendicular to the magnetic circuit. device. Made of magnetic material, the permanent magnet is fixed, and has a magnet support portion disposed on the first arm portion,
According to claim 2 or 3, characterized in that the vertical direction of the cross-sectional area S ₃ greater than the cross-sectional area S _1, S ₂ of the first and second arm portions to the magnetic circuit of the magnet support portion Magnetic switch device.   At least one of the base part and the first and second arm parts is provided with a through hole or a protrusion through which a fixing means for attaching the magnetic main body part to the support structure is inserted. The magnetic switch device as described in any one of Claims 2-4.   The magnetic switch device according to claim 1, wherein the second end of the magnetic main body has a protrusion that extends toward the magnetic sensor.   The said base part has an extension part extended toward the said to-be-detected body, when the to-be-detected body which consists of magnetic materials is arrange | positioned in the said opening part, The Claim 1 characterized by the above-mentioned. Magnetic switch device. A magnetic switch device according to any one of claims 1 to 7 arranged in one of an elevator hoistway or an elevator car;
An elevator car position detecting device, comprising: a detected body made of a magnetic material that is disposed on the other side of the elevator hoistway or the elevator car and moves in the opening in the vertical direction.

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