Rotary encoder

Abstract

[Problem] To provide a rotary encoder with which it is possible to reduce manufacturing costs.　[Solution] A rotary encoder 10 comprises a magnetic detection element 2 and a magnetic field generation part 3. The magnetic field generation part 3 is provided with a yoke 4. Because the magnetic field generating part 3 is provided with the yoke 4, it is possible to increase magnetic flux density. A permanent magnet may be used as the magnetic field generating part 3. Moreover, a magnetic plate-like body may be used as the yoke 4 which is provided at an end section of the magnetic field generation part 3, the end section being on a side further away from a magnetic power generation element.

Description

rotary encoder

[0001] The present invention relates to a rotary encoder, and more particularly to a rotary encoder that can be manufactured at reduced cost.

[0002] Conventional rotary encoders equipped with magnetic generating elements having the large Barkhausen effect use a magnetic field generating unit such as a magnet. Patent applications have been filed for rotary encoders equipped with magnetic generating elements having the large Barkhausen effect.

[0003] For example, Patent Document 1 listed below discloses a power generating element, an encoder, and a manufacturing method for a magnetic member that can increase power generation, which includes a power generating element consisting of a magnetic member that generates a large Barkhausen effect, a coil wound around the magnetic member, and a ferrite member provided at an end of the magnetic member, and a ferrite member consisting of a main body located inside a columnar space and a protrusion located outside. It also describes that the columnar space is surrounded by an imaginary plane that is formed when the outer edge of the coil is assumed to extend on both sides in the winding axis direction, and is formed so as to be sandwiched between two imaginary planes that contact both ends of the magnetic member and are perpendicular to the winding axis direction.

[0004] WO2022 / 230651 "Method for manufacturing a power generating element, an encoder, and a magnetic member"

[0005] A magnetic generator with the large Barkhausen effect cannot generate electricity unless there is a certain level of magnetic flux density. Therefore, depending on the product structure and the environment in which the product is used, a magnet that can generate a high magnetic flux density may be required, which ultimately leads to a rise in product costs.

[0006] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotary encoder that can reduce manufacturing costs in consideration of the problems of the prior art.

[0007] As a result of studying the above-mentioned problems, the inventors of the present application found that the problem can be solved by bringing a plate-shaped structure made of a magnetic material such as iron into contact with the side of a magnetic field generating section such as a magnet, away from the magnetic generating element, in a rotary encoder equipped with a magnetic generating element having a large Barkhausen effect, and having the plate-shaped structure act as a yoke. Further studies based on this finding led to the completion of the present invention. That is, the invention claimed in this application, or at least the invention disclosed therein, as a means for solving the above-mentioned problems is as follows:

[0008] [1] A rotary encoder including a magnetic detection element and a magnetic field generating unit, characterized in that a yoke is provided on the magnetic field generating unit. [2] A rotary encoder including a magnetic generating element having a large Barkhausen effect, a magnetic detecting element having a Hall effect or a magnetoresistance effect, and a magnetic field generating unit, characterized in that a yoke is provided on the magnetic field generating unit. [3] The rotary encoder according to either [1] or [2], characterized in that the magnetic field generating unit is configured by joining two or more magnetic field generating unit units magnetized in the axial direction in a radial direction, and adjacent magnetic field generating unit units are arranged so that their magnetic poles are opposite. [4] The rotary encoder according to either [1] or [2], characterized in that the yoke is a magnetic plate-like body. [5] The rotary encoder according to either [1] or [2], characterized in that the yoke is provided on an end of the magnetic field generating unit farther from the magnetic generating element.

[0009] Since the rotary encoder of the present invention is configured as described above, it is possible to increase the magnetic flux density compared to the conventional configuration without a yoke, and therefore it is possible to use a relatively inexpensive magnet with a low magnetic flux density, thereby reducing costs. Note that the technology disclosed in Document 1 relates to an encoder structure using a Wiegand wire sensor and is unrelated to the present invention.

[0010] Fig. 1 is a cross-sectional explanatory diagram conceptually showing the basic configuration of a rotary encoder of the present invention; Fig. 2 is a cross-sectional explanatory diagram conceptually showing the operation of the rotary encoder of the present invention; Fig. 3 is a cross-sectional explanatory diagram conceptually showing the basic configuration of a rotary encoder of the present invention equipped with a magnetic power generation element; Fig. 4 is a perspective explanatory diagram showing the basic configuration of a magnetic field generating unit of a rotary encoder of the present invention; Fig. 5 is a cross-sectional explanatory diagram of a main part showing an embodiment of a rotary encoder of the present invention;

[0011] The present invention will be described in detail below with reference to the drawings. Figure 1 is a cross-sectional explanatory diagram conceptually showing the basic configuration of a rotary encoder of the present invention. As shown in the figure, this rotary encoder 10 is a rotary encoder including a magnetic detection element 2 and a magnetic field generating unit 3, and its main configuration is that the magnetic field generating unit 3 is provided with a yoke 4. In this rotary encoder 10 with such a configuration, the magnetic flux density can be increased by providing the magnetic field generating unit 3 with a yoke 4. Further explanation will be made using another drawing.

[0012] 2 is a cross-sectional explanatory diagram conceptually illustrating the operation of the rotary encoder of the present invention. In the diagram, (a) shows the essential parts of the present invention, and (b) shows the essential parts of the prior art. In the prior art, magnetic field generating unit 93 generates magnetic fluxes F91 and F92 of equal magnitude and magnetic flux density ((b) in the diagram). On the other hand, in the present invention, where the magnetic flux density is increased by yoke 24, the magnetic flux generated by magnetic field generating unit 23 is magnetic flux F1 on the side opposite to the side where yoke 24 is provided, which is greater than magnetic flux F2 on the yoke 24 side. In this way, the present invention achieves the effect of increasing magnetic flux density by yoke 24.

[0013] 3 is a cross-sectional explanatory diagram conceptually showing the basic configuration of a rotary encoder of the present invention equipped with a magnetic power generating element. As shown in the figure, this rotary encoder 310 has the configuration described in FIG. 1, i.e., a magnetic detection element 32, a magnetic field generating unit 33, and a yoke 34 provided on the magnetic field generating unit 33, as well as a magnetic power generating element 35 having a large Barkhausen effect. In other words, a rotary encoder with such a configuration is also within the scope of the present invention.

[0014] In the rotary encoder 310 having such a configuration, the magnetic flux density can be increased by providing the yoke 34 in the magnetic field generating unit 33. This effect is as explained above with reference to Figure 2. The magnetic detection element 32 can have a structure that exhibits the Hall effect or magnetoresistance effect.

[0015] 3, the yoke 34 of the rotary encoder 310 of the present invention can be configured to be provided at the end of the magnetic field generating unit 33 that is farther away from the magnetic generating element 35. Note that a magnet or the like is used for the magnetic field generating unit 33, but a plate-like structure made of a magnetic material such as iron can be suitably used as the yoke 34. This is brought into contact with the side of the magnetic field generating unit 33 that is farther away from the magnetic generating element 35, and functions as the yoke 34.

[0016] For example, a plate-like structure such as a washer can be used as the yoke 34. The magnetic flux density can be designed to a desired or appropriate level by adjusting the thickness of the plate-like structure such as a washer, the number of plates to be stacked, and the like.

[0017] 4 is a perspective view illustrating the basic configuration of the magnetic field generating unit of the rotary encoder of the present invention. As shown in the figure, the magnetic field generating unit 43 is composed of two or more axially magnetized magnetic field generating unit units 49 joined together radially, with adjacent magnetic field generating unit units 49, 49 arranged so that their magnetic poles are different. That is, the magnetic field generating unit 49 located at the front of the figure has an N pole 46 at its top, while the adjacent magnetic field generating unit 49 located at the rear of the figure has an S pole 47 at its top. On the other hand, the magnetic poles are arranged in the opposite direction at the bottom of each magnetic field generating unit 49, 49. The figure also shows magnetic fluxes F1d, F1x, F2d, and F2x generated in the axial direction by the magnetic field generating unit 43.

[0018] 5 is an explanatory cross-sectional view of a main portion of an embodiment of a rotary encoder according to the present invention. As shown in the figure, the rotary encoder 510 of this embodiment includes a magnetic generating element 55 having the large Barkhausen effect, a magnetic detecting element 52 having the Hall effect or magnetoresistance effect, and a magnetic field generating unit 53, and is configured such that a yoke 54 is attached to a magnetic plate-like body at the end of the magnetic field generating unit 53 farther from the magnetic generating element 55. This allows for a higher magnetic flux density than in conventional configurations.

[0019] The rotary encoder of the present invention has a higher magnetic flux density than the conventional yoke-less configuration, which allows the use of relatively inexpensive magnets with low magnetic flux density, contributing to cost reduction. Therefore, this invention has high industrial applicability in encoder manufacturing, fields of use, and all related fields.

[0020] 1, 31, 51...Disk 2, 32, 52...Magnetic detection element 3, 23, 33, 43, 53...Magnetic field generation unit 4, 24, 34, 54...Yoke 8, 28, 38, 58...Shaft 10, 310, 510...Rotary encoder 35, 55...Magnetic power generation element 46...North pole 47...South pole 49...Magnetic field generation unit 50...Substrate F1, F1d, F1x, F2, F2d, F2x...Magnetic flux 93...Magnetic field generation unit 98...Shaft F91, F92...Magnetic flux

Claims

1. A rotary encoder comprising a magnetic detection element and a magnetic field generating unit, characterized in that the magnetic field generating unit is provided with a yoke.

2. A rotary encoder comprising a magnetic generating element having the large Barkhausen effect, a magnetic detecting element having the Hall effect or magnetoresistance effect, and a magnetic field generating unit, characterized in that the magnetic field generating unit is provided with a yoke.

3. A rotary encoder as described in either claim 1 or 2, characterized in that the magnetic field generating unit is constructed by joining two or more magnetic field generating unit units magnetized in the axial direction together in the radial direction, and adjacent magnetic field generating unit units are arranged so that their magnetic poles are different.

4. A rotary encoder according to claim 1 or 2, wherein the yoke is a plate-shaped body made of a magnetic material.

5. The rotary encoder according to claim 1 or 2, wherein the yoke is provided at an end of the magnetic field generating unit farther from the magnetic generating element.

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