JP2002267405A - Displacement meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable measurement even with a distance of around 10 mm away from a object to be measured by adjusting a bias magnetic field acting to a Hall element by an electromagnet even when a distance to a position of the object to be measured is changed. SOLUTION: The displacement meter 31, which measures a displacement quantity of the object to be measured of a ferromagnetic material, comprises the Hall elements 33, 34 placed with facing to the object to be measured and the electromagnet that can adjust strength of the magnetic field placed at a rear of these Hall elements 33, 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement meter for detecting the passage of a rolling element, which is a ferromagnetic material, and the amount of displacement of the ferromagnetic material.

[0002]

2. Description of the Related Art Conventionally, as a sensor (displacement meter) for detecting the passage of a rolling element, for example, those shown in FIGS. 1A and 1B are known. Here, FIG. 1A is an explanatory view of a rolling bearing provided with a sensor, and FIG. 1B is a detailed view of the sensor.

[0003] Reference numeral 1 in the figure denotes a cylindrical casing. Inside the casing 1, a rotating shaft 2 is arranged coaxially with the casing 1. A plurality of ferromagnetic steel balls (rolling elements) 6 surrounded by an outer ring 3, an inner ring 4, and a retainer 5 made of a non-magnetic material are provided between the casing 1 and the rotating shaft 2.
Is arranged. The casing 1 and the outer ring 3 are composed of lubricating rings 7a and 7b having a central opening, and a cylindrical pressing plate 8.
Supported by Here, the outer ring 3, the inner ring 4,
The cage 5 and the rolling elements 6 are collectively called rolling bearings.

The casing 1 and oil supply rings 7a, 7
b are provided with lubrication holes 9a and 9b, respectively.
a and 7b are provided with fueling nozzles 1 communicating with the fueling holes 9a and 9b.
0a and 10b are provided respectively. The oil supply hole 9a,
9b and oil supply nozzles 10a and 10b are for supplying oil, which is a lubricant, to the rolling elements 6. A spacer 11 and a tightening nut 12 are provided on the outer peripheral portion of the rotating shaft 2 on one side of the inner ring 4, and the inner ring 4 is engaged with the rotating shaft 2 by these. A cover 14 is disposed at one end of the rotating shaft 2 via an oil seal 13 so as to be located at an end of the holding plate 8.

[0005] A sensor (displacement gauge) 15 is disposed on one oil supply ring 7b corresponding to the rolling element 6.
This sensor 15 has a configuration shown in FIG. Reference numeral 16 in the figure denotes a sensor case, and an active first Hall element 17 is arranged inside the sensor case 16. Inside the sensor case 16, a second Hall element 18 on the dummy side is arranged to face the first Hall element 17. A magnet 20 is arranged between the first and second Hall elements 17 and 18 via insulators 19a and 19b made of a non-magnetic material. On the other end of the second Hall element 18, an insulator 19c made of a non-magnetic material is arranged. Lead wires 21 and 22 are connected to the first and second Hall elements 17 and 18, respectively. These lead wires 21 and 22 are
The resin is taken out through the inside of the resin filling 23. Note that reference numeral 24 in FIG. 1B indicates a mounting screw.

[0006] The rolling elements such as balls and rollers of a rolling bearing are usually housed in a cage. For this reason, as shown in FIG. 1 (A), the rolling element 6 has to be installed at a fixed distance from the sensor 12, specifically, about 2 mm to 10 mm.

However, in the conventional sensor, when an attempt is made to measure the displacement at a position distant from the sensor, the output voltage difference with respect to the distance is as shown in FIG.
When it exceeds 4 mm, it hardly occurs, and when it exceeds 10 mm, it is difficult to detect the rolling elements. Therefore, in order to detect the displacement of the rolling element at a distant distance, there is a disadvantage that the magnet must be replaced with a strong magnet and the sensor must be remodeled.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. Therefore, a Hall element disposed opposite to an object to be measured made of a ferromagnetic material, and a Hall element disposed on the back of the Hall element are provided. With the configuration including an electromagnet capable of adjusting the strength of the magnetic field, even if the distance to the position of the object to be measured fluctuates, the bias magnetic field acting on the Hall element is adjusted by the electromagnet, and is separated by about 10 mm. It is an object of the present invention to provide a displacement meter that can measure even at a distance.

[0009]

A displacement meter according to the present invention comprises:
In a displacement meter for measuring a displacement amount of an object to be measured made of a ferromagnetic material, a Hall element arranged opposite to the object to be measured and a strength of a magnetic field arranged on a back surface of the Hall element can be adjusted. And an electromagnet.

Further, the displacement meter according to the present invention is a displacement meter which is arranged on a rolling bearing having a rolling element inside a casing so as to face the rolling element and detects the passage of the rolling element. A recess is formed in the oiling ring near the rolling element, and the first active side
And a second Hall element on the dummy side disposed in the recess in opposition to the first Hall element, and an interposed insulator between the first and second Hall elements. An electromagnet capable of adjusting the strength of a magnetic field, and a lead wire connected to the first and second Hall elements are provided.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.
I do. In the present invention, the Hall element is shown in FIG.
When a constant current is applied to the element,
A feature that outputs a voltage corresponding to the magnitude of a vertically acting magnetic field
It has nature. In FIG. 2, T₁, T₃Are each input
Terminal₂, T ₄Indicates an output terminal. Also,
Even when a constant voltage is applied, the lower
It is known that the output voltage can be obtained.

In the case of the constant current method: Vh = Rh / d × Ic × B In the case of the constant voltage method: Vh = μh × W / L × Vin × B where Vh: Hall output voltage, Ic: control current, R
h: Hall coefficient, d: Thickness of Hall element, μh: Electron mobility of semiconductor, W: Width of sensitive part, L: Length of sensitive part. By applying a magnet to the back of the Hall element by applying this principle and moving the ferromagnetic material toward and away from the sensor, the strength of the magnetic field of the Hall element changes, and a voltage corresponding to the distance is obtained.

When the Hall element Ha is a circuit as shown in FIG. 3 and the Hall element Ha is arranged as shown in FIG. 4, for example, the relationship between the distance h at 26 ° C. and the output voltage is shown in FIGS. It is as shown. In addition, distance 1mm
The relationship between the ambient temperature and the output voltage is as shown in FIG. Thus, only one Hall element has a large drift amount with respect to temperature.

Therefore, for example, as shown in FIG.
Two Hall elements are arranged opposite to each other with a magnet interposed therebetween. One is an active Hall element Ha that senses the strength of the magnetic field in response to the distance from the ferromagnetic material, and the other is a magnet and a sensor case (ferromagnetic). The hall element Hd on the dummy side whose distance to the body does not change is combined. FIG. 6 shows this circuit diagram.

In the present invention, it is preferable that a magnet is provided at a position facing the Hall element with the object to be measured interposed therebetween. As a result of a test with a magnet provided, it was found that the output voltage difference with respect to distance did not decrease so much as compared with the case without the magnet as shown in FIG. Therefore, the perceived magnetic field of the Hall element becomes large, and it becomes possible to detect a rolling element at a position separated by about 10 mm. Further, even if an electromagnet capable of adjusting the strength of a magnetic field is used instead of the magnet, the same effect as that of the magnet can be obtained.

In the present invention, a ferromagnetic steel ball or a steel ball or a roller is used from a location about 10 mm away from the rolling element such as a steel ball or a roller, without applying a marker such as magnetization or a notch to the retainer. Since the passage of a rolling element such as a roller can be detected, it is possible to determine whether the motion of the rolling bearing is normal or abnormal.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 Referring to FIG. However, since the displacement meter according to the first embodiment is used in the state shown in FIG. 1A, the reference numerals used in FIG. 1A are used as they are. The sensor (displacement meter) 31 of FIG. 9 is used instead of the sensor of FIG.

In FIG. 7, reference numeral 32 denotes a sensor case. Inside the sensor case 32, a first Hall element 33 on the active side is arranged. Inside the sensor case 32, a second Hall element 34 on the dummy side is arranged to face the first Hall element 33. An iron core 36 is arranged between the first and second Hall elements 33 and 34 via insulators 35a and 35b made of a non-magnetic material. A coil 37 is wound around the iron core 36.
On the other end side of the second Hall element 34, an insulator 35c made of a non-magnetic material is arranged. Lead wires 38 and 39 are connected to the first and second Hall elements 33 and 34, respectively. These lead wires 38 and 39 pass through the inside of the cylindrical resin filling 40 and the columnar resin filling 41 and are taken out to the outside. The copper wires 42 and 43 from the coil 37 are also taken out through the resin fillers 40 and 41. Reference numeral 44 denotes a mounting screw.

As described above, the displacement meter 3 according to the first embodiment
Reference numeral 1 denotes a first Hall element 33 on the active side, a second Hall element 34 on the dummy side arranged opposite to the first Hall element 33, and the first and second Hall elements 3.
A core 36 disposed between insulators 3 and 34 via insulators 35a and 35b, a coil 37 wound around the core 36, and lead wires connected to the first and second Hall elements 33 and 34, respectively. 38, 39, and copper wires 42, 43 connected to the coil 37, and the like.

In such a displacement meter, the coil 37
When an alternating current is passed through the core, the iron core 36 becomes a magnet. In addition, when the current to the coil 37 is increased, the magnetic force of the iron core 36 is increased, and the perceived magnetic force of the first Hall element 33 is increased. Therefore, the presence or absence of a distant ferromagnetic substance can be detected. Therefore, even if the displacement meter 31 is separated from the rolling element 6 by about 10 mm, the passage of the rolling element 6 can be reliably detected, and the operating state of the rolling bearing can be grasped. Also, the displacement meter 31
Since the installation position and conditions of use are eased, it can be installed in various places.

Embodiment 2 Referring to FIG. 8 and FIG. Here, FIG. 8 is an explanatory view of a rolling bearing provided with the displacement meter according to the second embodiment, and FIG. 9 is an enlarged view of a main part of FIG. However, the same members as those in FIG. 1A will be described with the same reference numerals.

Reference numeral 1 in the drawing indicates a cylindrical casing. Inside the casing 1, a rotating shaft 2 is arranged coaxially with the casing 1. A plurality of steel balls (rolling elements) 6 made of a ferromagnetic material surrounded by an outer ring 3, an inner ring 4, and a retainer 5 made of a nonmagnetic material are provided between the casing 1 and the rotating shaft 2.
Is arranged. The casing 1 and the outer ring 3 are composed of lubricating rings 7a and 7b having a central opening, and a cylindrical pressing plate 8.
Supported by

The casing 1 and the oil supply rings 7a, 7
b are provided with lubrication holes 9a and 9b, respectively.
a and 7b are provided with fueling nozzles 1 communicating with the fueling holes 9a and 9b.
0a and 10b are provided respectively. The oil supply hole 9a,
9b and oil supply nozzles 10a and 10b are for supplying oil, which is a lubricant, to the rolling elements 6. A spacer 11 and a tightening nut 12 are provided on the outer peripheral portion of the rotating shaft 2 on one side of the inner ring 4, and the inner ring 4 is engaged with the rotating shaft 2 by these. A cover 14 is disposed at one end of the rotating shaft 2 via an oil seal 13 so as to be located at an end of the holding plate 8.

A recess 51 is provided inside one oil supply ring 7a at a position facing a magnet of a sensor described later.
A magnet 52 is fitted into the recess 51. A sensor (displacement gauge) 53 is disposed on the other oil supply ring 7b. This sensor 53 has the configuration shown in FIG. Reference numeral 16 in the figure is a sensor case,
The first side of the active side is located inside the sensor case 16.
Are arranged. Inside the sensor case 16, a second Hall element 18 on the dummy side is arranged to face the first Hall element 17. An insulator 19 is provided between the first and second Hall elements 17 and 18.
The magnet 54 is arranged via a and 19b. On the other end side of the second Hall element 18, an insulator 18c made of a non-magnetic material is arranged. Lead wires 21 and 22 are connected to the first and second Hall elements 17 and 18, respectively. These lead wires 21 and 22 are drawn out through the inside of the resin filling 23.

According to the second embodiment, the first Hall element 17 on the active side, the second Hall element 18 on the dummy side opposed to the first Hall element 17, and the first An insulator 19a is provided between the second Hall elements 17 and 18.
19b and the first and second magnets 54
Lead wires 2 connected to the Hall elements 16 and 17, respectively.
The displacement gauge 53 is constituted by 1, 2 and the like, and the magnet 52 is disposed on the oil supply ring 7a facing the magnet 54 of the displacement gauge 53.

As described above, in the second embodiment, since the magnet 52 is disposed on the oil supply ring 7a facing the magnet 54 of the displacement meter 53, the output voltage with respect to the distance can be understood from the test results shown in FIG. Since the difference does not decrease so much, the perceived magnetic field of the first Hall element 17 increases,
The rolling element 6 at a position separated by about mm can be detected. On the other hand, in the conventional sensor, when trying to measure the displacement of the rolling element at a distance, the output voltage difference with respect to the distance is small as shown by the solid line in FIG.
The detection of rolling elements at a position separated by about mm was the best.

In the second embodiment, the case in which the oil supply ring is provided with a magnet has been described. However, the present invention is not limited to this, and may be replaced with an electromagnet capable of adjusting the strength of the magnetic field.

In the first and second embodiments, the displacement meter for detecting the passage of a rolling element made of a ferromagnetic material has been described. However, the present invention is not limited to this, and the displacement meter for detecting the displacement amount of the ferromagnetic material is also applicable. It is equally applicable.

[0029]

As described above in detail, according to the present invention, the intensity of the magnetic field disposed on the back surface of the Hall element disposed opposite to the DUT made of ferromagnetic material is reduced. Adjustable bias magnetic field acting on the Hall element is adjusted by the electromagnet even if the distance to the position of the device to be measured is changed, or the magnet is arranged at the opposing position even if the distance to the position of the object to be measured is changed by using the configuration including the adjustable electromagnet. Accordingly, it is possible to provide a displacement meter which can measure even at a distance of about 10 mm and which can be installed in various places by relaxing the installation position and use conditions.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a rolling bearing incorporating a conventional Hall element.

FIG. 2 is an explanatory view showing the operation principle of a Hall element.

FIG. 3 is a schematic circuit diagram when one Hall element according to the present invention is used.

FIG. 4 is a schematic configuration diagram of the Hall element in FIG. 3;

FIG. 5 is a characteristic diagram showing a relationship between an ambient temperature and an output voltage when the Hall element of FIG. 4 is performed under a certain condition.

FIG. 6 is a circuit diagram when two Hall elements according to the present invention are used.

FIG. 7 is an explanatory diagram of a displacement meter according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram of a displacement meter according to a second embodiment of the present invention.

FIG. 9 is an enlarged view of a main part of FIG. 8;

FIG. 10 is a characteristic diagram showing a relationship between a distance and an output voltage when a conventional sensor is used.

FIG. 11 is a characteristic diagram showing a relationship between a distance measured by a sensor and an output voltage when another magnet is arranged at a position facing the magnet of the displacement meter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Casing, 2 ... Rotating shaft, 3 ... Outer ring, 4 ... Inner ring, 5 ... Cage, 6 ... Steel ball (rolling element), 7a, 7b ... Oiling ring, 8a, 8b ... Oiling hole, 9a, 9b ... Oiling Nozzle, 11 spacer, 12 tightening nut, 14 cover, 16, 32 sensor case, 17, 33 first Hall element (Ha), 18, 34 second Hall element (Hd), 19a , 19b, 19c, 35a, 35b, 35c ... insulator, 23, 41, 42 ... resin filling, 31, 53 ... sensor (displacement gauge), 36 ... iron core, 37 ... coil, 38, 39 ... lead wire, 42, 43: copper wire, 52, 54: magnet.

Claims (3)

[Claims] 1. A displacement meter for measuring a displacement amount of an object to be measured made of a ferromagnetic material, wherein a Hall element arranged to face the object to be measured and a strength of a magnetic field arranged on a back surface of the Hall element. A displacement meter comprising: an electromagnet whose height can be adjusted. 2. A rolling bearing having a rolling element inside a casing is disposed so as to face the rolling element,
A displacement meter that detects the passage of the rolling element, a concave portion is formed in an oil supply ring near the rolling element, and a first active-side Hall element disposed in the concave portion;
A second Hall element on the dummy side arranged in the recess in opposition to the first Hall element, and the strength of a magnetic field arranged between the first and second Hall elements via an insulator. The displacement meter according to claim 1, further comprising: an adjustable electromagnet; and a lead wire connected to the first and second Hall elements. 3. The displacement meter according to claim 1, wherein a magnet or an electromagnet is provided at a position facing the Hall element with the object to be measured interposed therebetween.