JPH11271093A - Magnetic encoder device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic encoder in which a void between an element for electromagnetic conversion and an object to be detected can be easily managed, use can be varied, and manufacture can be attained at low coats even in the case of a small amount of production. SOLUTION: A electromagnetic converting part 1 having a magnetic drum 10a in which the polarity of magnetic poles are alternately changing along a circumferential direction to which multiple polarization is operated, and face mounting type holes IC4 for detecting the magnetic field of the magnetic drum 10a in which at least two or more face mounting type holes IC4 are positioned at an FPC 2 is curved surface-set while a void between the magnetic drum 10a and the face mounting type holes IC4 is maintained to be constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a magnetic encoder device capable of detecting a rotation angle, a position, a speed, and the like used in a mechatronics device, an automobile, and the like.

[0002]

2. Description of the Related Art In recent years, with the increasing performance of various industrial equipment,
There is an increasing demand for highly accurate and highly reliable encoders.
Among them, magnetic encoder devices are widely used under severe conditions of use environment where dust, oil and the like are scattered.

[0003] In a magnetic encoder device, there is a magnetic encoder device for a small motor in which a magnetoresistive element is deposited on an FPC (flexible printed circuit board) and the curved surface is arranged in accordance with the curvature of a magnetic drum as a detection object. . That is,
This is a means for keeping a constant gap between each of the magnetoresistive elements and the magnetic drum when a plurality of magnetoresistive elements are to be arranged, and is proposed in Japanese Patent Application Laid-Open No. 9-159485.

[0004]

By the way, the encoder device using the magnetoresistive element has a narrow operating point and a very small gap between the magnetic drum and the object to be detected because the magnetic field saturation characteristic of the magnetoresistive element is small. Must be kept small and constant. For this reason, applications are limited to small motors and the like with high rotation accuracy.

[0005] Further, since it is necessary to form a pattern on the FPC in a form including the magnetoresistive element, the cost increases in small-scale production.

In view of the above, the present invention facilitates the management of the gap between the element for magnetoelectric conversion and the object to be detected, is versatile, and can be manufactured at low cost even in small-scale production. It is an object to provide a magnetic encoder.

[0007] Other objects and novel features of the present invention will be clarified in embodiments described later.

[0008]

In order to achieve the above-mentioned object, the present invention provides a magnetic drum which is multipolar magnetized and whose polarity of a magnetic pole alternates along a circumferential direction. A magnetic encoder device having a magneto-electric conversion element for detecting a magnetic field of a drum, wherein at least two or more surface-mounted Hall ICs or Hall elements as the magneto-electric conversion element are FP.
The magnetoelectric conversion section positioned and fixed at C is arranged on a curved surface while keeping a constant gap between the magnetic drum and the surface-mounted Hall IC or Hall element.

Further, the surface mounting type hole I of the FPC
The surface opposite to the surface on which C or the Hall element is arranged may be installed facing the magnetic drum.

[0010] The magnetic drum may be composed of a composite magnet, or the composite magnet may be integrated with a cylindrical part.

The arrangement interval of the surface-mounted Hall ICs or Hall elements is represented by the following condition: P _IC = 2 mP _MAG ± (P _MAG / n) where P _{IC is} the arrangement interval of the surface-mounted Hall ICs (or Hall elements). m: an integer of 1 or more P _MAG : magnetization width per pole of the magnetic drum n: number of surface-mounted Hall ICs (or Hall elements) should be satisfied.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a magnetic encoder device according to an embodiment of the present invention.

A first embodiment of the magnetic encoder device according to the present invention will be described with reference to FIGS. FIG. 1 shows an overall configuration of a magnetic encoder device, and FIG. 2 shows a magnetoelectric conversion unit (FPC unit) of the magnetic encoder device. In these figures, the magnetoelectric conversion unit 1 is one in which a surface-mounted Hall IC (or Hall element) 4 is mounted on a flexible FPC (flexible printed circuit board) 2 on which a circuit pattern 3 is formed. Here, as shown in FIG. 2, the circuit pattern 3 is a conductor pattern for positioning and fixing five surface-mounted Hall ICs 4 at regular intervals, and each surface-mounted Hall IC 4 is provided on one side of the circuit pattern 3. The circuit pattern 3 is fixed by soldering at regular intervals, and the other side of the circuit pattern 3 is drawn out to the external connection edge 2a of the FPC 2.

In the overall configuration of FIG. 1, reference numeral 10a denotes a magnetic drum which has been subjected to multipolar magnetization, and has a configuration in which the polarity of the magnetic poles on the outer peripheral surface alternates along the circumferential direction. The magnetic drum 10a is composed entirely of, for example, a composite magnet (plastic magnet, rubber magnet) having N and S poles formed with the same magnetization width on the outer circumference, which is a circumferential surface, or N.S. , And S-poles are integrated with a composite magnet (plastic magnet, rubber magnet) having the same magnetization width. In particular, if the rubber magnet is wound around the outer periphery of the cylindrical part, the magnetic drum 10a can be manufactured at low cost and without variation in magnetization. Reference numeral 11a denotes an annular housing made of a nonmagnetic material, which surrounds the outer periphery of the magnetic drum 10a and
The magnetoelectric conversion unit 1 having an inner peripheral surface (circumferential surface) concentric with the rotation center of a and having a surface-mounted Hall IC 4 mounted on the FPC 2 as shown in FIG. Have been. Each surface-mounted Hall IC 4 for detecting a magnetic field in opposition to the magnetic poles on the outer periphery of the magnetic drum 10a is disposed on a curved surface with a certain gap from the magnetic drum 10a, and the element mounting surface of the FPC 2 faces the magnetic drum 10a. ing.

FIG. 3 shows an example of an output signal of the magnetic encoder device according to the present embodiment, which is mounted on the surface of the magnetic drum 10a such that the magnetized width P _MAG per pole corresponds to an array interval obtained by equally dividing into five. The mold Hall IC 4 is arranged. If the magnetization width P _MAG of the magnetic drum 10a is sufficiently larger than the surface mounting type Hall IC 4, the surface mounting type Hall IC 4 may be directly arranged at a position where the magnetization width P _MAG is divided into five equal parts. Since the magnetized width is smaller than that of the surface-mounted Hall IC 4, the arrangement is defined by the following equation (1).

P _IC = 2 m P _MAG ± (P _MAG / n) (1) where P _{IC is} an arrangement interval of surface-mounted Hall ICs (or Hall elements) m: an integer of 1 or more P _MAG : one of magnetic drums Magnetization width per pole n: Number of surface-mounted Hall ICs (or Hall elements)

As a result, the rotation of the magnetic drum 10a with respect to the annular housing 11a can be detected with an accuracy of 1 / n of the magnetization width P _MAG .
The third Hall IC 4 is the output signal a of FIG. 3, the second Hall IC 4 is the output signal b, the third Hall IC 4 is the output signal c, the fourth Hall IC 4 is the output signal d, and the fifth Hall IC 4 is the output signal. e can be output.

According to the first embodiment, the following effects can be obtained.

(1) A surface-mounted Hall IC (or Hall element) 4, a flexible FPC 2 for positioning and wiring a plurality of Hall ICs, and a multipolar magnetized rubber as a detection object A non-magnetic housing 1 having a magnetic drum 10a such as a magnet and a circumferential surface concentric with the rotation center of the magnetic drum 10a
1a, using a surface-mounted Hall IC (or Hall element) having a wide operating point as a magnetoelectric conversion element and a magnetic drum magnetized at a relatively large pitch, a large gap between them can be obtained, The influence on the run-out of the drum can be reduced, and the gap can be easily managed. As a result,
Applications can be expanded.

(2) According to a desired resolution, a plurality of surface-mounted Hall ICs (or Hall elements) 4 are arranged on the FPC 2 with their phases shifted, and are fixed along a surface having the same curvature as the magnetic drum 10a. By doing, each surface mounting type Hall IC
The air gap between the magnetic drum (or the Hall element) and the magnetic drum is kept constant, and a stable multi-phase signal is obtained. In addition, when the surface-mounted Hall IC (or Hall element) 4 is soldered to the FPC 2, an appropriate jig is used, so that the arrangement interval can be kept constant.

(3) Since the surface-mounted Hall IC (or Hall element) 4 and the FPC 2 are composed of separate components, the surface-mounted Hall IC (or Hall element) can be shared with other products. Since the wiring pattern is also simplified, the magnetoelectric conversion unit 1 can be manufactured at low cost even if it is manufactured in small quantities.

FIG. 4 shows a magnetic encoder device according to a second embodiment of the present invention. In this figure, reference numeral 10b denotes a magnetic drum subjected to multipolar magnetization, which has a configuration in which the polarity of the magnetic pole on the inner peripheral surface alternates along the circumferential direction. The magnetic drum 10b has a composite magnet (plastic magnet,
It is composed entirely of a rubber magnet) or integrated with a composite magnet (plastic magnet, rubber magnet) in which the N and S poles are formed with the same magnetization width on the inner periphery of the cylindrical part.
In particular, if a rubber magnet is attached to the inner periphery of the cylindrical component, the magnetic drum 10b can be configured at low cost and without variation in magnetization. Reference numeral 11b denotes a non-magnetic annular housing, which is disposed inside the inner periphery of the magnetic drum 10b and has an outer peripheral surface concentric with the rotation center of the magnetic drum 10b.
Surface mount type Hall IC (or Hall element) 4 as FP
The magnetoelectric converter 1 mounted on C2 is fixed upside down. That is, each of the surface-mounted Hall ICs 4 is arranged on a curved surface while keeping a constant gap in the magnetic drum 10b.
Is opposite to the magnetic drum 10b.

The structure according to the second embodiment is easy to adopt a dustproof and waterproof structure. Other functions and effects are the same as those of the first embodiment. Further, the relationship between the magnetization width per pole on the magnetic drum 10b side and the arrangement interval of the surface-mounted Hall ICs (or Hall elements) may satisfy the above-described formula (1).

FIG. 5 is a third embodiment of the present invention showing a case where the magnetic encoder device shown in the second embodiment is applied to an electric assist bicycle. In this figure,
Reference numeral 20 denotes a body frame of the battery-assisted bicycle, a support pipe 21 rotatably supporting the crankshaft 30, a seat post 22 rising upward from the support pipe 21, and a pair of right and left rear forks extending rearward from the support pipe 21. 23L, 23R and the like. A saddle is mounted on the upper end of the seat post 22, and the rear forks 23L, 23
A rear wheel, which is a drive wheel, is journalled between the rear ends of R.

The left and right ends of the crankshaft 30 penetrating the support pipe 21 have crank pedals 31L, 3L.
1R are fixedly connected to each other to receive rotation input from a pedal. A rotating disk 40 is attached to the crankshaft 30 and the crank pedal 31R via a one-way clutch 32. That is, the inner ring 33 of the one-way clutch 32 is provided on the outer peripheral side of the crankshaft 30 and is fixed to the crank pedal 31R, and the rotating disk 40 is fixed to the clutch outer ring 34. The one-way clutch 32 transmits the rotational torque of the crankshaft 30 in the forward rotation direction to the rotary disk 40, but does not transmit the reverse direction rotational torque to the rotary disk 40.

A sprocket 50 (which transmits driving force to driving wheels via a chain) is rotatably provided around the crankshaft 30 concentrically with the rotating disk 40, and is provided via a coil spring 42. Thus, the rotational torque of the rotating disk 40 is transmitted. That is, the rotating disk 40 is sandwiched between the sprocket 50 and the holding plate 51 by the caulking pin 52, and the pin 52 penetrates the elongated hole 41 of the rotating disk 40, so that the sprocket 50 Can be displaced in the rotation direction within a predetermined rotation angle range. Therefore, the forward rotation of the crankshaft 30 is transmitted to the sprocket 50 via the one-way clutch 32, the rotating disk 40, and the coil spring 42, and the coil spring 42 extends in proportion to the transmission torque. The displacement in the rotation direction of 50 is proportional to the transmission torque.

In order to detect the transmission torque, two magnetic encoders described in the second embodiment are used for detecting the rotation of the rotating disk 40 and the rotation of the sprocket 50 in total. That is, the magnetoelectric conversion unit 1-1 of the first and second magnetic encoders 60-1 and 60-2.
1, 1-2 are fixedly arranged on the outer peripheral surface of a mounting member 61 fixed to the vehicle body frame side, and a first magnetic encoder 60-1 is provided.
The magnetic drum 10b-1 facing the magnetoelectric conversion unit 1-1 is fixed to the inner peripheral side of the first annular member 71 fixed to the rotating disk 40. Therefore, the first magnetic encoder 60-1
Performs rotation detection of the rotating disk 40. Similarly, the magnetic drum 10b-2 facing the magnetoelectric conversion part 1-2 of the second magnetic encoder 60-2 is fixed to the inner peripheral side of the second annular member 72 fixed to the sprocket 50. The second magnetic encoder 60-2 detects the rotation of the sprocket 50.

In this case, the output signals of the magnetoelectric conversion units 1-1 and 1-2 of the first and second magnetic encoders 60-1 and 60-2 are compared with each other, so that the rotation disc 40 and the sprocket 50 are compared. Transmission torque, in other words, each crank pedal 3
The weight applied to 1R and 31L can be detected.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims. There will be.

[0030]

As described above, according to the magnetic encoder device of the present invention, the magneto-electric conversion unit is formed by combining the surface-mounted Hall IC (or Hall element) and the FPC, so that a curved surface can be formed. Placement and wiring can be performed accurately and easily. As a result, a large gap is formed between the magnetic drum and the object to be detected, the influence of vibration and the like can be reduced, and the use can be expanded.

Further, since the wiring pattern of the FPC is simple, it is possible to provide an inexpensive magnetic encoder even with a small amount.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing a first embodiment of a magnetic encoder device according to the present invention.

FIG. 2 is a front view showing a magnetoelectric conversion unit used in the first embodiment.

FIG. 3 is a diagram illustrating each surface-mounted hole I according to the first embodiment.
FIG. 4 is a waveform diagram illustrating an example of an output signal of C (or a Hall element).

FIG. 4 is a plan sectional view showing a second embodiment of the magnetic encoder device of the present invention.

FIG. 5 is a third embodiment of the present invention, wherein the second
It is a sectional side view showing the case where the magnetic encoder device shown in an embodiment is applied to an electric assist bicycle.

[Explanation of symbols]

 1, 1-1, 1-2 Magnetoelectric conversion unit 2 FPC (flexible printed circuit board) 3 Circuit pattern 4 Surface mounting type Hall IC (or Hall element) 10a, 10b, 10b-1, 10b-2 Magnetic drum 11a, 11b Housing Reference Signs List 20 body frame 30 crankshaft 40 rotating disk 42 coil spring 50 sprocket 60-1, 60-2 magnetic encoder

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuo Miura 2-1-1, Minamiaoyama, Minato-ku, Tokyo Inside Honda R & D Co., Ltd.

Claims (4)

[Claims] 1. A magnetic encoder device comprising: a magnetic drum that is multipolar magnetized and whose polarity of a magnetic pole alternates along a circumferential direction; and a magnetoelectric conversion element that detects a magnetic field of the magnetic drum. The magnetic drum and the surface-mounted Hall IC, wherein at least two or more surface-mounted Hall ICs as magneto-electric conversion elements or a magneto-electric conversion part in which Hall elements are positioned and fixed to an FPC are fixed.
Alternatively, a magnetic encoder device characterized in that a curved surface is provided while keeping a constant gap with a Hall element. 2. The magnetic encoder device according to claim 1, wherein a surface of the FPC opposite to a surface on which the surface-mounted Hall effect IC or the Hall element is arranged faces toward the magnetic drum. 3. The magnetic encoder device according to claim 1, wherein the magnetic drum is composed of a composite magnet, or the composite magnet is integrated with a cylindrical part. 4. An arrangement interval of the surface-mounted Hall IC or Hall element is as follows: P _IC = 2 mP _MAG ± (P _MAG / n) where P _{IC is a} surface-mounted Hall IC (or Hall element). The arrangement interval m: an integer of 1 or more P _MAG : magnetization width per pole of the magnetic drum n: the number of arranged surface-mounted Hall ICs (or Hall elements). Magnetic encoder device.