JPH07128566A - Moving quantity detector - Google Patents

Abstract

PURPOSE:To provide the moving quantity detector which permits easy working, magnetizing and assembling of a magnetic member disposed on a moving body and is small in size and low in the cost. CONSTITUTION:The moving quantity detector for detecting the moving quantity of a turning barrel 2 disposed freely movably relative to a stationary barrel 1 includes the planar magnetic member 6 which is elastically deformed and fixed to the turning cylinder 2 after magnetization with predetermined magnetic patterns and is formed to have a flexible surface and to plane and a magneto- resistance element 9 which is held by having a predetermined spacing so as to face the magnetic patterns of the magnetic member 6 and detects the movement of the magnetic member 6 according to the movement of the turning barrel 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving amount detecting device, and more particularly to a moving amount detecting device for detecting the moving amount of a moving member provided so as to be movable relative to a fixed member.

[0002]

2. Description of the Related Art Conventionally, various technical means for accurately and stably detecting the position or speed of a moving body have been proposed. For example, a displacement of an optical pattern with a fine pitch provided on the moving body has a light emitting element. There is known an optical detection means for detecting the position or speed of the moving body by detecting with a photodetector.

Further, in Japanese Patent Laid-Open No. 1-148078, a rigid magnetic member magnetized with a predetermined pattern according to the shape of the moving body is fixed to the moving body, and the displacement of the magnetic pattern is fixed. There is disclosed a magnetic detection mechanism for detecting with an MR element provided in. In addition to the above, as the magnetic detection mechanism, various technical means for detecting a magnetic pattern by a magnetic sensing element utilizing a magnetic induction effect, a Hall effect, etc. have been proposed.

On the other hand, the following technical means are known as a method for manufacturing a magnetic member having the above magnetic pattern.

The first means is to directly coat the surface of the moving body with a magnetic material in which a ferromagnetic powder such as iron, cobalt, nickel or the like is dispersed in a binder, and use a magnetizing device to form a predetermined magnetic pattern. It is magnetized.

As a second means, a predetermined magnetic pattern is attached by a magnetizing device to a metal magnet material or a plastic magnet material which is molded or machined according to the shape of the minute magnetic pattern installation portion in the moving body. It was magnetized to fix the magnetic pattern to the minute magnetic pattern installation portion of the moving body.

[0007]

However, in the above technical means, when a magnetic pattern having a fine pitch of several μm to several 100 μm is formed, it is very troublesome to manufacture a magnetic detection mechanism having the pattern. Will be things. That is, when the moving body is directly coated with a magnetic material, the coating surface of the moving body has a surface accuracy equivalent to the fine pitch of the magnetic pattern (roundness, concentricity, surface roughness, etc. in the case of a cylindrical surface). I need. Further, when the moving body is attached to the jig for performing the above-mentioned coating, the same accuracy is required for the attachment reference plane.

Further, on the above-mentioned coating surface, it is necessary to stack several films each having a film thickness of several μm, which complicates the apparatus. Further, the coating surface has to be formed as a projecting surface on the surface of the moving body, which limits the flexibility of the shape and size of the moving body.

Further, even after the magnetic material is coated, when the magnetized surface is polished by several μm to magnetize the minute magnetic pattern, it is necessary to control the space between the magnetized head and the magnetized surface with high precision. There is.

Further, as described above, also when the metal magnet material and the plastic magnet material are used as the magnetic member, the magnetized surface of the magnetic member and the surface to be attached to the moving body depend on the magnetized pitch as in the case of coating. It requires high processing accuracy. Furthermore, for example, in the case of molding, it is necessary to manufacture the mold with high precision,
It takes a lot of time to manufacture the mold, and in some cases, the mold cannot be manufactured. Further, it is difficult to make these magnetic members thin (very difficult when the thickness is 1 mm or less) because of the necessity of maintaining the processing accuracy, and as a result, they have become large as a position detecting mechanism.

In addition to these, both of the above two methods require a highly accurate processing jig and a magnetizing jig depending on the shape of the moving body, which causes an increase in cost.

The present invention has been made in view of the above problems, and provides a small-sized and low-cost movement amount detecting device in which the magnetic member provided on the moving body can be easily processed, magnetized, and assembled. The purpose is to do.

[0013]

In order to achieve the above object, a movement amount detecting device according to the present invention detects a movement amount of a moving member provided so as to be movable relative to a fixed member. In the quantity detecting device, a plate-shaped magnetic member having a smooth surface and being elastically deformed and fixed to the moving member after being magnetized with a predetermined magnetic pattern, A magnetic detection element that is held on the fixed member with a predetermined gap facing the magnetic pattern of the magnetic member and that detects the movement of the magnetic member that accompanies the movement of the moving member. To do.

[0014]

In the movement amount detecting apparatus according to the present invention, the magnetic member is magnetized with a predetermined magnetic pattern and then elastically deformed and fixed to the moving member. Further, the magnetic detection element is held on the fixed member with a predetermined gap so as to face the magnetic pattern of the magnetic member, and detects the movement of the magnetic member that accompanies the movement of the moving member. .

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an external perspective view of a movement amount detecting device showing a first embodiment of the present invention. Further, FIG. 2 is a sectional view showing in detail a main part of the movement amount detecting device.

As shown in the figure, this movement amount detecting device is
On the outer periphery of the fixed barrel 1 having the optical axis 0 as the center, a rotary barrel 2 is fitted so as to be rotatable about the optical axis 0. The rotary cylinder 2 is held immovably in the optical axis 0 direction by the pusher 3.

A partial gear 2a is circumferentially arranged on the outer peripheral portion of the rotary cylinder 2, and the partial gear 2a is connected to a motor 5 via a reduction gear train 4 provided on a fixed portion (not shown). Is connected to the pinion gear 5a fixed to the output shaft of the. As a result, the rotation cylinder 2 is rotated by the rotation of the motor 5.

A circumferential groove 2b is formed in the outer circumference of the rotary cylinder 2 in the circumferential direction, and a projection 2c is provided at a predetermined position of the circumferential groove 2b.

On the other hand, a plate-shaped magnetic member 6 made of a magnetic material having elasticity, in which the S pole portions and the N pole portions are alternately magnetized in the longitudinal direction, is fixed along the circumferential groove 2b. There is. A hole 6a corresponding to the protrusion 2c is formed at one end of the magnetic member 6, and the magnetic member 6 is fitted into the protrusion 2c to determine the circumferential position. Further, an adhesive 7 is applied to the back surface of the magnetized surface of the magnetic member 6 and is adhered along the circumferential groove 2b. The magnetic member 6
Is slightly narrower than the circumferential groove 2b. As a result, the position of the magnetic member 6 in the optical axis direction is precisely determined.

A magnetoresistive element 9 held by a holder 8 is arranged at a position facing the magnetized surface of the magnetic member 6. The distance between the magnetoresistive element 9 and the magnetic member 6 is determined by a spacer 10 fixed to the magnetoresistive element 9. Further, by fixing the holder 8 to the outer frame 12 integrated with the fixed frame 1 with the screw 11, the pressing force acts between the magnetic resistance element 9 and the magnetic member 6 by the spring portion 8a, and the gap is It is always kept constant.

Between the magnetoresistive element 9 and the holder 8, one end of a flexible printed circuit board 13 is sandwiched, and an electric terminal 13a provided on the end of the flexible printed circuit board 13 (see FIG. 4). (See) and the electric terminal of the magnetoresistive element 9 are joined. The other end of the flexible printed board 13 is connected to an external predetermined circuit, and the magnetoresistive element 9 is supplied with a power supply voltage from a power source (not shown) through the flexible printed board 13 and outputs its output signal. It is adapted to be transmitted to the predetermined circuit.

A power source (not shown) is connected to the magnetoresistive element 9 via the flexible printed circuit board 13 as described above, and generates an electric signal corresponding to the magnetic pattern of the magnetic member 6 as well as externally. An electric signal is output to a predetermined circuit of the above.

FIG. 3 is a cross-sectional view of an essential part showing a bonded state of the magnetic member 6 and the rotary cylinder 2.

As shown in FIG. 3A, the magnetizing pitch P of the magnetic member 6 is usually set to about 40 μm to 200 μm. On the other hand, the element surface of the magnetoresistive element 9 and the magnetic member 6
The magnetized surface of No. 2 is the interval x (Fig. 2) of about 50% of the magnetized pitch.
If you keep the value), you will have the highest sensitivity. Further, it is required that the variation of the above-mentioned interval is kept within about ± 20% of the optimum interval (the interval when the sensitivity is highest).
This is because when the distance fluctuates beyond the fluctuation range described above, the resistance value of the magnetoresistive element 9 changes due to the change in the direction of the magnetic force lines 6b, so that an accurate electric signal corresponding to the magnetic pattern can be output. Because it may disappear.

Here, considering the case where the magnetizing pitch is 200 μm, the variation of the interval is ± due to the reason described above.
About 20 μm is required. In order to maintain this accuracy, it is needless to say that the dimensional accuracy and surface accuracy of the spacer 10 are maintained, but the surface accuracy of the magnetic member 6 must also be maintained high.

However, as shown in FIG. 3 (b), assuming that the processing accuracy of the mounting portion of the magnetic member 6 in the rotary cylinder 2 is not very high and the rigidity of the magnetic member 6 itself is low, the magnetic member 6 is not processed. 6 bends, and the interval x changes. As a result, the magnetic force lines 6b are disturbed, and as described above, the magnetoresistive element 9 cannot output a correct output corresponding to the magnetic pattern.

In view of this situation, it is desirable to suppress the surface roughness of the magnetic member 6 to several μm or less and the change in the thickness direction to several tens of μm or less. In this embodiment, a magnetic material is used for the plastic-based film. A coated material is used. The shape of the magnetic member 6 is preferably a shape having a base thickness that is at least twice the surface roughness of the rotary cylinder 2 in consideration of its rigidity (see FIGS. 3A and 3B).

More specifically, in the present embodiment, the magnetic member 6 has a base material made of vinyl chloride, PET (polyethylene terephthalate) resin or the like having a thickness of 0.1 to 0.2 mm, and a barium ferrite magnetic material. It is configured by coating. As a result, the magnetic member 6 is excellent in rigidity and holding power.

In order to increase the magnetizing strength, a thin plate of a metal magnet material, such as S, is used instead of the above material.
Fe-Cr- such as PINEX (trademark of Yamaha Corporation)
You may use Co type alloy. Even when a magnetic member having such rigidity is fixed to the rotary cylinder 2 with a double-sided adhesive tape,
The magnetized surface of the magnetic member does not undulate, and a reliable magnetic pattern signal output can be obtained.

Since the magnetic member has a smooth surface and is flexible, a highly accurate magnetic pattern can be easily magnetized in advance by using a magnetic tape magnetizing device or a magnetic card magnetizing device. It is possible. A highly accurate magnetic member can be efficiently manufactured by cutting into a predetermined shape by a pressing device after magnetized. Further, if the positioning hole of the magnetic member is also formed by the pressing device, high accuracy can be maintained. Furthermore, if an adhesive is applied in advance to the sticking surface of the magnetic member and a backing paper is stuck, the sticking work to the moving member becomes extremely easy.

In this embodiment, the spacer 10 is made of a resin sheet having low friction and abrasion resistance. Since the resin sheet is non-magnetic, it does not disturb the magnetic output of the magnetic pattern, and since it is an insulator, there is no risk of short-circuiting the wire connection portion of the magnetoresistive element. Specific materials include polyimide,
Tapes such as polyester and vinyl chloride are used.

Further, as the spacer 10, a phosphor bronze plate, an aluminum plate or the like, which is a non-magnetic metal material, may be coated with an insulating coating. Also,
The contact surface with the magnetic member may be coated with a dry lubricant such as fluororesin, Teflon (registered trademark of DuPont), molybdenum disulfide, or grease or oil to reduce the frictional force.

FIG. 4 is a detailed perspective view of the magnetoresistive element 9 in the first embodiment.

In the present embodiment, the magnetoresistive element 9 is formed on the ceramic substrate 9d on the side where the spacer 10 is attached.
Two magnetic resistors 9a are formed. Predetermined connection lines 9b are connected to the magnetic resistors 9a, and element terminals are drawn out through the through holes 9c to the connection surface side of the ceramic substrate 9d with the flexible printed board 13. Further, the element terminal is connected to the terminal 13a of the flexible printed board 13. In addition,
In this embodiment, ceramic is used as the material of the substrate of the magnetoresistive element 9, but the material is not limited to this, and a glass substrate may be used. Further, the connection with the flexible printed board 13 may be made on the surface on which the magnetoresistive element 9 is formed.

FIG. 5 is a cross-sectional view of essential parts showing a movement amount detecting device of a second embodiment of the present invention.

The second embodiment is an embodiment in which the spacer 10 which determines the distance between the element surface of the magnetoresistive element 9 and the magnetized surface of the magnetic member 6 in the first embodiment is omitted.

As shown in the figure, in this embodiment, the magnetic member 6 is made slightly thicker than the depth of the circumferential groove 2b of the rotary cylinder 2 as compared with the first embodiment. Further, the rotating cylinder 2
The low-friction tape 15 coated with the adhesive 16 is adhered across the outer peripheral surface of the magnetic member 6 and the magnetized surface of the magnetic member 6 that slightly protrudes from the outer peripheral surface. 6 is fixed to the rotary cylinder 2.

The element surface of the magnetoresistive element 9 is in direct contact with the surface of the low friction tape 15. That is, in this embodiment, the element surface of the magnetoresistive element 9 and the magnetic member 6 are arranged.
Only the low-friction tape 15 is present between the magnetized surface and the spacer 10, and the spacer 10 in the first embodiment is omitted.

The thickness of the low friction tape 15 is set so that the distance between the element surface of the magnetoresistive element 9 and the magnetized surface of the magnetic member 6 is optimum. As a result, the low-friction tape 15 protects and fixes the magnetic member 6 and also plays the same role as the spacer 10 in the first embodiment. In this embodiment, as the low friction tape 15, a polyimide tape excellent in strength, abrasion resistance and low friction is used.

The other structure is the same as that of the first embodiment, and the description thereof is omitted here.

As described above, in the second embodiment, the first
In addition to the need for the spacer 10 in the embodiment, the magnetic member 6 need not be adhered to the rotating cylinder 2 either, resulting in a simpler configuration.

FIG. 6 is a front view of essential parts showing a movement amount detecting device according to a third embodiment of the present invention.

In the third embodiment, the magnetic member 6 is formed on a plastic base 16b and a magnetic layer 16a made of a magnetic material.
It is an example which was configured by coating.

The magnetic member 6 has a rotating cylinder 2 on the side of the magnetic layer 16a.
It is fixed to the side with an adhesive or the like. Further, the magnetoresistive element 9 is in contact with the surface of the plastic base 16b, and the spacer 10 is omitted as in the second embodiment.

The thickness of the plastic base 16b is set so that the element surface of the magnetoresistive element 9 and the magnetic layer 16a have an appropriate distance.

According to the third embodiment having such a structure, the structure can be simpler than that of the second embodiment.

FIG. 7 is an external perspective view showing a movement amount detecting device of a fourth embodiment of the present invention, and FIG. 8 is an enlarged sectional view of an essential part showing an essential part of the fourth embodiment. .

The fourth embodiment is an embodiment in which the present invention is applied to position detection of a lens barrel driven by a linear cam.

As shown in the figure, the lens barrel of the present embodiment is provided with a known fixed frame 21 and a movable frame 22 movably installed inside the fixed frame 21. A cam groove 21a is formed on the outer peripheral surface of the. The cam groove 21a has a roller screw 24 on the outer peripheral surface of the moving frame.
The roller 23 fixed by means of is engaged with the cam groove 21.
It is designed to move along a. Accordingly, when the movable frame 22 is rotated in a predetermined direction with respect to the fixed frame 21, the movable frame 22 is moved in the optical axis direction while rotating in the same direction. In addition,
The lens 20 is fixed to the moving frame 22, and the lens 20 moves back and forth in the optical axis direction.

A groove (not shown) is provided on the outer peripheral surface of the moving frame 22 in a direction along the cam groove 21a of the fixed frame 21a, and stripes are arranged in the groove in the optical axis direction. A strip-shaped magnetic member 26 having a magnetic pattern is adhesively fixed.

On the other hand, a window portion 21b is formed in the fixed frame 21 at a position facing the magnetized surface of the magnetic member 26. Further, in the window portion 21b, the magnetoresistive element 9 held by the holder 8 similar to that of the first embodiment is held by being pressed against the magnetized surface of the magnetic member 26 via the spacer 10.

The fourth embodiment thus constructed detects the position of the moving frame 22 which is moved forward and backward relative to the fixed frame 21 in the same manner as the first embodiment.

Although it has been extremely difficult for the conventional technical means to perform such a position detecting mechanism for the moving frame which moves forward and backward, it can be easily realized according to the fourth embodiment.

In each of the above-mentioned embodiments, the magnetic detecting element is used as the movement detecting element of the magnetic member, but a normal magnetic head or hall element due to other electromagnetic effect may be used. Further, it goes without saying that the present invention is not applied only to the position detection of the rotary moving body, but is also effective for the straight moving body.

As described above, according to each of the above-mentioned embodiments, the magnetic pattern can be precisely magnetized in advance on the flat plate-shaped magnetic member, and high accuracy can be obtained without using a special magnetizing jig. You can magnetize with certainty. Further, since the magnetic member has flexibility, it can be easily attached even if the moving body has a curved shape, and it does not take up space because it can be configured with a thin plate.

Further, even if the magnetic member is damaged, it is extremely easy to convert the magnetic member, magnetizing and assembly are extremely easy to manufacture, and the cost is low, the space is small, and the position can be detected with high accuracy. .

[0058]

As described above, according to the present invention, it is possible to provide a small-sized and low-cost movement amount detecting device in which the magnetic member provided on the moving body can be easily processed, magnetized and assembled.

[Brief description of drawings]

FIG. 1 is an external perspective view of a movement amount detection device showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing in detail a main part of the movement amount detection device of the first embodiment.

FIG. 3 is a cross-sectional view of essential parts showing a bonded state of a magnetic member and a rotary cylinder in the movement amount detecting device of the first embodiment.

FIG. 4 is a detailed perspective view of a magnetoresistive element in the movement amount detecting device of the first embodiment.

FIG. 5 is a cross-sectional view of essential parts showing a movement amount detection device according to a second embodiment of the present invention.

FIG. 6 is a front view of essential parts showing a movement amount detecting device according to a third embodiment of the present invention.

FIG. 7 is an external perspective view showing a movement amount detection device according to a fourth embodiment of the present invention.

FIG. 8 is an enlarged sectional view of an essential part showing an essential part of the movement amount detecting device of the fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fixed cylinder 2 ... Rotation cylinder 5 ... Motor 6 ... Magnetic member 7 ... Adhesive 8 ... Holder 9 ... Magnetoresistive element 10 ... Spacer 12 ... Fixed part 13 ... Flexible printed circuit board

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[Procedure amendment]

[Submission date] January 25, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

As shown in the figure, this movement amount detecting device is
On the outer periphery of the fixed barrel 1 having the optical axis 0 as the center, a rotary barrel 2 is fitted so as to be rotatable about the optical axis 0. The rotating barrel 2 is held immovably in the optical axis 0 direction by a presser 3.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

The electric element of the magnetoresistive element 9 is a flexible element.
Electric terminal 1 provided at the end of the printed circuit board 13
3a (see Fig. 4) and solder or conductive adhesive
It is joined. On the other hand, the flexible printed circuit board 13
Is installed at a predetermined position of the holder 8 and is fixed by adhesion.
The magnetic resistance element 9 is fixed at a predetermined position of the holder 8.
Has been. The other end of the flexible printed board 13 is connected to an external predetermined circuit, and the magnetoresistive element 9 is connected.
Is supplied with a power source voltage from a power source (not shown) via the flexible printed circuit board 13 and transmits its output signal to the predetermined circuit.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

More specifically, in the present embodiment, the magnetic member 6 has a base material made of vinyl chloride, PET (polyethylene terephthalate) resin or the like having a thickness of 0.1 to 0.2 mm, and a barium ferrite magnetic material. It is configured by coating. Accordingly, the magnetic member 6, the rigidity and the coercive magnetic force is superior in high points.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction content]

A groove (not shown) is provided on the outer peripheral surface of the moving frame 22 in the direction along the cam groove 21a of the fixed frame 21a, and the groove has a striped shape along the optical axis direction.
A strip-shaped magnetic member 26 having a magnetic pattern in which magnetic pressure is aligned
Are glued and fixed.

[Procedure Amendment 5]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure correction 6]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

[Procedure Amendment 7]

[Document name to be corrected] Drawing

[Correction target item name] Figure 8

[Correction method] Change

[Correction content]

[Figure 8]

Claims (1)

[Claims] 1. A moving amount detecting device for detecting a moving amount of a moving member provided so as to be relatively movable with respect to a fixed member, wherein the moving member is magnetized with a predetermined magnetic pattern. A plate-shaped magnetic member that is elastically deformed and fixed and has a smooth surface, and a predetermined gap on the fixed member that faces the magnetic pattern of the magnetic member. And a magnetic detection element that is held and held, and that detects the movement of the magnetic member that accompanies the movement of the moving member.