JPS62265522A - Rotation detecting device - Google Patents

Abstract

PURPOSE:To obtain an extremely small-sized, high-resolution rotation detecting device by providing a magnetic sensor opposite a magnetic recording part which is subjected to multipole magnetization at the periphery of a rotating shaft provided rotatably by bearings. CONSTITUTION:The magnetic recording part 6 which is subjected to multipole magnetization so that their polarities are alternately inverted in the rotating direction of the rotating shaft 1 provided rotatably to a holder 2 by the bearings 3 and 4 and fixed to a fixed shaft 5 is arranged on the peripheral surface of the rotating shaft 1 between the bearings 3 and 4. On the other hand a magnetic sensor 7 is fixed to a magnetic sensor fitting part 8 opposite the magnetic recording part 6 and this sensor 7 is used to transduce the periodic variation of a magnetic field produced by the rotation of the rotating shaft 1 into an electric signal. With this assembly, vibrations of the magnetic recording part 6 to the magnetic sensor 7 due to the rotation of the rotating shaft 1 are extremely small, so the gap length between the magnetic sensor 7 and magnetic recording part 6 and the recording wavelength of the recording part 6 are reducible, so that high resolution is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a rotation detection system that can detect rotation angles and rotation speeds by converting periodic changes in the magnetic field generated by rotation into electrical signals. Regarding equipment.

[Prior art]

Conventionally, as this type of rotation detection device, the
No. 988 etc. are known. As shown in FIG. 4, a rotating shaft 104 is installed in a cage 10 in a rotational manner by a pair of bearings 102 and 103, and a holding cylinder 105 is connected to this rotating shaft 104 so that the rotating direction can be adjusted as shown in FIG. A rotating disk having a magnetic recording n106 in which the S-N poles are magnetized head-to-head at the recording wavelength λ]O is fixed, and the above magnetic recording section]06
[iB air sensor 108 is disposed at a position opposite to].

When the rotating shaft 104 rotates, this rotation detecting device detects the magnetic recording part 106 of the rotating disk 107 facing the magnetic sensor]08.
Since the strength of the magnetic field leaking from the rotary shaft 104 changes periodically, the magnetic sensor 108 generates an electrical output according to the change in the magnetic field strength, and the rotation angle and rotation speed of the rotating shaft 104 can be determined.

In such a conventional magnetic rotation detection device, in order to obtain a thick output from the magnetic sensor 08, the gap length between the magnetic recording section 06 of the rotating disk 107 and the magnetic sensor 108 is set so that they do not touch each other. It is required that the rotating disk 107 be placed close to each other within the range.
It is necessary to increase the number of magnetized poles per rotation by shortening the recording wavelength λ of It became necessary to make it even smaller.

In order to obtain a sufficient output from the general VC'tIi air sensor [08], it is thought that the cap length with the magnetic sensor [08] needs to be approximately equal to or less than the recording wavelength λ of the rotating disk 107. There is. Incidentally, the recording wavelength λ of currently commercially available magnetic rotation detection lengths is about 50 μm or more.

However, according to such a device (according to which the recording wavelength is further shortened in order to increase the detection resolution), the magnetic recording section 10
Although it is necessary to reduce the gap length between the magnetic sensor 6 and the magnetic sensor 108, it is difficult to reduce the gap length due to the large vibration of the rotating disk [07] in the direction of the rotation axis for the following reasons. .

1. Rotating disc] 07 itself has a large diameter compared to its thickness,
In addition, warping occurs due to processing distortion caused by press punching.

2. The rotating disc]07 is fixed to the rotating shaft 104 via the holding cylinder]05, but the installation of the holding cylinder]050 rotating disc may be due to misalignment of the perpendicularity between the surface and the axis of the inner diameter, or the holding cylinder]05. Axis of rotation】
Due to the insertion play with 04, the rotating disk 07 swings in the direction of the rotation axis.

3. When attaching the rotary disk 107 to the holding cylinder 305, the rotary disk 07 is deformed due to screw tightening. 3 So,
Rotating disk】07 To reduce the runout, rotating disk】07
It is possible to remove it by etching, finish it by lapping, improve the accuracy of holding cylinder machining, and tighten the screws with a torque of 9.
I: It is necessary to manage the product, but this will make the product price high (
turn into.

On the other hand, if you only want to increase the resolution, you can increase the outer diameter of the rotating disk (and increase the number of magnetizing poles), but this will increase the external size of the device and increase the moment of inertia. There are disadvantages such as higher

Incidentally, in recent years, there has been a demand for a rotation detecting device that is ultra-compact, high resolution, low moment of inertia, and low cost, and can be used in drive devices for compact disks and 70-P disks.

[Problem that the invention seeks to solve]

In the conventional technology, a rotating disk]07Km air recording section 106? :
The rotating shaft 101 (rotating disk because it is fixed) is attached to the magnetic sensor via the holding cylinder 05 (the rotating disc is fixed) 07 is greatly photographed.
It was not possible to set the gap length between the rotary disc 107 and the magnetic recording section 106 of the rotary disk 107 to be small, and it was not possible to simultaneously make the device smaller, have higher resolution, lower the moment of inertia, and lower the cost. .

This invention was made in view of such problems, and it is necessary to install the magnetic recording section and the magnetic, air, and air cells.
It is an object of the present invention to provide a rotation detection device that can increase the gap length and reduce the gap length.

[Means and effects for solving the problem] The present invention solves the above problem by providing a magnetic sensor on the circumferential surface of a rotary shaft rotatably provided in a bearing, facing a multi-pole M-magnetized magnetic recording section. The rotation angle and rotation speed can be detected by converting periodic changes in the magnetic field generated as the rotation shaft rotates into electrical signals.

[Prices J] An embodiment of the present invention will be described below in accordance with the drawings. @1
In the figure, reference numeral 1 denotes a rotating shaft rotatably provided in a retainer 2 by a pair of bearings, for example bearings 3.4, and fixed by a fixed ring 5.The WR surface rc of this rotating shaft has its polarity reversed in the direction of rotation. A multi-pole magnetized magnetic recording g6 is placed between the bearings 3 and 4. A magnetic sensor 7 is provided opposite to this magnetic Ie recording section for converting periodic changes in the magnetic field generated with the rotation of the rotation axis into 11L air fJ@. At once, the sensor 7 connects the magnetic recording part 6 to the part 8 before or after the magnetic recording part 6 is fitted into the pair of bearings 3 and 4 (the magnetic sensor installed in the retainer 2 is installed in the part 8). Fixed.

Here, the rotation axis] is, for example, Subinotal transformation type FeC
It is made of a single material such as an rC□-based magnet, and is finished with a magnetic 72 mm on the outer diameter corresponding to the diameter of the bearing 3 or 40 circular ring to be inserted, for example, using a centerless polishing machine. - Processed.

The rotary shaft prepared in this way is inserted into a ring-shaped magnet from the outside so that the direction of the magnetic field inside the rotary shaft is almost the same as the direction of rotation as shown in Figure 2. The rotary shaft 10 is magnetized by sequentially reversing the polarity in the rotational direction, thereby forming an N-magnetized rotary shaft.

Next, other embodiments of the invention will be described.

In this embodiment, the rotating shaft is made of a non-61I material such as non-magnetic stainless steel or non-magnetic ceramics.

A groove part 9 as shown in FIG.
As a layer, a hard magnetic material such as the aforementioned FeCrCo magnet or a plastic magnet containing 7-elite magnetic powder is deposited by plating or vapor deposition. Thereafter, centerless polishing and annealing were performed in the same manner as in the previous embodiment, so that the rotating shaft and the attached magnetic recording portion 60 were made the same surface, and as shown in FIG. A rotating shaft 1 made of a magnetic material is formed.

In this way, by forming the rotating shaft with a non-magnetic material and layering a hard magnetic material as a magnetic recording part on the rotating shaft made of the non-magnetic material by plating or vapor deposition, it is possible to ℃There is no leakage of the magnetic field to the outside, and the remaining magnetic field that moves in the magnetic center becomes stronger (so magnetic detection becomes more reliable and the degree of rotation detection improves.Also, the hard magnetic material as the magnetic recording part Plating or vapor deposition, etc. (formed in a thinner film form, making it easier to magnetize.

The magnetic rotation detection device with the configuration shown above does not require the rotating disk required in the prior art, and also requires a holding cylinder for attaching the rotating disk to the rotating shaft! Because there is no rotation, as a natural result, the rotation of the rotation axis is
The deflection in the direction of the magnetic sensor 7 is extremely small, and the deflection is determined by the deflection of the inner ring of the bearing 3.4 and the roundness of the rotation axis. [rotational axis to be detected]] The gap length with the upper magnetic recording section 6 can be made extremely small. Normal bearings 3.4 The runout of the inner ring is less than 5 μm for small diameter bearings.Since it is easy to reduce the roundness of the shaft to less than 1 μm, it is possible to reduce the gap length to less than 0 μm. . Therefore, the recording wavelength of the magnetic recording section 6 of [rotating shaft] is also 10μ.
m or less, and high resolution can be achieved.

Further, according to the VC of the present invention, there is no need for a rotating disk or a holding cylinder, which required highly accurate machining compared to the conventional technology, and there is no need for assembling these or the number of man-hours required for Ig assembly.

Furthermore, according to the present invention, the moment of inertia can be reduced because a rotating disk and a holding cylinder are not required.

Furthermore, when the rotating shaft moves in the axial direction due to external stress, the gap length changes in the conventional technology, causing the magnetic sensor and the rotating disk to come into contact or become too far apart to be detected. If so, the gap length is stable because it does not change structurally.

Note that this invention is not limited to the above embodiments (
, various modifications can be made without changing the gist.

In the Kaminori Ori example, in order to reduce the deflection of the magnetic recording section in the direction of the magnetic sensor, the connection between the pair of bearings (the magnetic recording section
ll, but if runout is not a problem, only one bearing may be used. In addition, for the bearing of the rotating shaft,
Instead of bearings, metal shafts such as oil-less metal may be used.

In addition, in the embodiment, a rotating shaft magnetized with 7W magnets and magnetized in various degrees Celsius is inserted into the bearing, but this does not apply even if the rotating shaft is inserted into the bearing M or ffa. Compared to conventional technology, the wavelength of the magnetic recording section that must be detected by the magnetic sensor can be made extremely small, so it has the characteristics of being compact, high resolution, low moment of inertia, and low cost, all of which can simultaneously satisfy VC. have

[Brief explanation of drawings]

Figure 1 is part of this invention! A schematic configuration diagram showing Example A, FIG. 2 is 51! FIG. 3 is an explanatory diagram for explaining another practical example of the rotating shaft of the present invention, and FIG. 4 is a schematic diagram showing a conventional oral history detection device.
The configuration diagram '@5 is an explanatory diagram showing the magnetic recording section of the apparatus. 1... Rotating shaft 2... Cage 3.4... Bearing 5... Fixed ring 6... Speed recorder 7
...Magnetic sensor 8...Magnetic sensor is installed in the

Claims (1)

[Claims] (1) A rotary shaft rotatably provided in a bearing, a magnetic recording section magnetized with multipoles on the circumferential surface of the rotary shaft, and a magnetic recording section disposed opposite to the magnetic recording section to prevent rotation of the rotary shaft. A rotation detection device comprising: a magnetic sensor that detects a rotation angle and rotation speed by converting a periodic change in a magnetic field generated accordingly into an electric signal.