JP7158863B2 - Magnetic sensor device and position detection device - Google Patents

Description

The present invention relates to a magnetic sensor device including a magnetic sensor element and a case, and a position detection device that relatively moves the magnetic sensor device along the surface of a magnetic scale.

A magnetic linear encoder (position detection device) relatively moves a magnetic sensor device along a magnetic scale on which tracks in which N poles and S poles are alternately arranged linearly are formed. Patent Document 1 discloses this type of magnetic linear encoder. A magnetic linear encoder disclosed in Patent Document 1 includes a magnetic sensor device in which a magnetic sensor is mounted in a rectangular parallelepiped case (holder) made of a non-magnetic material. The holder has an opposing surface facing the magnetic scale, and the magnetic sensor is arranged in an opening formed in the opposing surface. A magnetic sensor includes a sensor substrate and a magnetoresistive element (magnetic sensor element) formed on the surface of the sensor substrate.

Patent Document 2 discloses a magnetic sensor device used in a magnetic linear encoder. In the magnetic sensor device of Patent Document 2, a magnetic sensor is arranged at the bottom of a rectangular parallelepiped case (housing), and a board on which a connector for connecting a cable, an LED, and the like are mounted is arranged inside the case. be.

JP 2017-102089 A JP 2014-102163 A

In the magnetic linear encoder of Patent Document 1, a magnetic scale is provided with a plurality of tracks, and in the magnetic sensor device, a magnetoresistive element is provided on a substrate so as to face each track, and a detection signal corresponding to each track is generated. Output. A detection signal from the magnetoresistive element is input to a signal processing circuit mounted on the circuit board. The signal processing circuit includes an analog circuit for amplifying the detection signal of the magnetoresistive element, an A/D converter, and a microprocessor such as an MPU.

In the magnetic sensor device, when a circuit board on which a signal processing circuit is mounted is placed inside a case that holds the magnetic sensor, the magnetic sensor may be affected by magnetization of electronic components on the circuit board. In Patent Document 2, the sensor surface is covered with a metallic shield member in order to reduce the influence of external electrical noise on the magnetoresistive element. However, no shield is provided to reduce the magnetic influence from the circuit board housed inside the magnetic sensor device.

SUMMARY OF THE INVENTION In view of the foregoing, an object of the present invention is to reduce the magnetic influence of the circuit board on the magnetic sensor element in a magnetic sensor device having a circuit board on which electronic components are mounted.

In order to solve the above problems, the present invention provides a magnetic sensor device that moves relative to a magnetic scale, comprising a magnetic sensor element, a circuit board on which electronic components are mounted, the magnetic sensor element and the circuit. a case for holding a substrate; and a shield member arranged between the magnetic sensor element and the circuit board. At least one side of an outer peripheral edge of the shield member is bent toward the magnetic sensor element , the magnetic sensor element is provided on a sensor substrate, and the shield member is attached to the sensor substrate. The case includes a through portion through which a wiring member to be connected passes through, the case includes a bottom plate portion forming a facing surface facing the magnetic scale, the bottom plate portion includes an opening, and the magnetic scale on the outer peripheral side of the opening. The sensor substrate is fixed to the bottom plate portion from the facing surface side, and the shield member is configured to be separated from the sensor substrate with respect to the bottom plate portion. It is arranged on the opposite side, and is positioned at a position where the opening and the through portion overlap by inserting the positioning convex portion into the through portion .

According to the present invention, the shield member is arranged between the magnetic sensor element and the substrate when the same case holds the magnetic sensor element and the circuit board on which the electronic components are mounted. By doing so, the shield member can reduce the magnetic influence from the electronic components mounted on the circuit board. Therefore, it is possible to suppress the deterioration of the accuracy of position detection by the magnetic sensor element.

Also, according to the present invention, the magnetic sensor element is positioned inside the outline of the shield member when viewed from the circuit board side . Therefore , the magnetic influence from the side on which the circuit board is arranged can be reduced.

Furthermore, according to the present invention, at least one side of the outer peripheral edge of the shield member is bent toward the magnetic sensor element . Therefore , the magnetic influence from the outer peripheral side of the magnetic sensor element can be reduced.

According to the present invention, the magnetic sensor element is provided on a sensor substrate, and the shield member has a through portion through which a wiring member connected to the sensor substrate is passed . Therefore , the wiring member can be easily routed, and the wiring space can be reduced. For example, when the wiring member is a flexible printed circuit board, it is preferable to form a linearly extending slit as the through portion. By doing so, the flexible printed circuit board can be easily routed to the side of the magnetic sensor element. Furthermore, by forming the through portion instead of the notch, it is possible to reduce the magnetic influence from the side on which the circuit board is arranged.

According to the present invention, the case includes a bottom plate portion forming a facing surface facing the magnetic scale, and the bottom plate portion includes an opening and a side opposite to the magnetic scale on the outer peripheral side of the opening. The sensor substrate is fixed to the bottom plate portion from the facing surface side, and the shield member is disposed on the opposite side of the bottom plate portion from the sensor substrate, By inserting the positioning convex portion into the through portion, the opening portion and the through portion are positioned to overlap each other . Therefore , the wiring member can be passed through the portion where the through portion and the opening overlap. Moreover, since the positioning of the shield member can be easily performed, the mounting work of the shield member can be easily performed.

In the present invention, the case includes an opening and two sensor support portions protruding inward of the opening from two opposing locations on the edge of the opening, and the sensor substrate includes the sensor support portions at the two locations. It is preferably fixed to the support. By doing so, it is possible to suppress stress from being applied to the sensor substrate via the case. Therefore, it is possible to suppress deterioration in accuracy of position detection by the magnetic sensor element due to stress applied to the sensor substrate.

In the present invention, the shield member is preferably fixed to the case with an adhesive. By doing so, it is possible to reduce the number of parts since there is no need to use fixing members such as screws. Moreover, since it is not necessary to provide a fixing structure such as a fixing hole in the shield member and the case, the shapes of the shield member and the case can be simplified.

In the present invention, it is preferable to provide a conductive member having one end electrically connected to the shield member and the other end electrically connected to the case. With this configuration, the shield member can be reliably connected to the ground potential through the case, so that the shield member is less susceptible to external electrical noise.

In the present invention, the electronic component constitutes a signal processing circuit to which the detection signal of the magnetic sensor element is input. By doing so, it is possible to construct a magnetic sensor device in which the magnetic sensor section and the signal processing section are integrated.

Next, in the position detecting device of the present invention, there is provided the magnetic scale having a track in which N poles and S poles are alternately arranged in a straight line, and the magnetic scale provided so as to be relatively movable in the extending direction of the track with respect to the magnetic scale. and the above magnetic sensor device.

According to the present invention, the shield member is arranged between the magnetic sensor element and the substrate when the same case holds the magnetic sensor element and the circuit board on which the electronic components are mounted. By doing so, the shield member can reduce the magnetic influence from the electronic components mounted on the circuit board. Therefore, it is possible to suppress the deterioration of the accuracy of position detection by the magnetic sensor element. In addition, when viewed from the circuit board side, the magnetic sensor element is positioned inside the outline of the shield member, so that the magnetic influence from the side on which the circuit board is arranged can be reduced. Furthermore, since at least one side of the outer peripheral edge of the shield member is bent toward the magnetic sensor element, magnetic influence from the outer peripheral side of the magnetic sensor element can be reduced. In addition, the wiring member can be easily routed, the wiring space can be reduced, and the magnetic influence from the side on which the circuit board is arranged can be reduced. Furthermore, since the shield member can be easily positioned, the shield member can be easily attached.

1 is a perspective view of a position detection device to which the present invention is applied; FIG. FIG. 3 is an exploded perspective view of the magnetic sensor device viewed from the side of the facing surface facing the magnetic scale; FIG. 2 is a cross-sectional view of the magnetic sensor device (a cross-sectional view taken along line AA in FIG. 1); 2 is a cross-sectional view of the magnetic sensor device (a cross-sectional view taken along line BB in FIG. 1); FIG. 1 is an exploded perspective view of a magnetic sensor device; FIG. 1 is an exploded perspective view of a magnetic sensor device; FIG. It is explanatory drawing which shows the assembly method of a magnetic sensor apparatus.

Embodiments of a magnetic sensor device and a position detection device to which the present invention is applied will be described below with reference to the drawings.

(Position detector)
FIG. 1 is a perspective view of a magnetic encoder device 1 as an embodiment of a position detection device to which the present invention is applied. A magnetic encoder device (position detection device) 1 includes a magnetic scale 2 and a magnetic sensor device 3 that reads the magnetic scale 2 . The magnetic scale 2 has a magnetic track 4 extending in a first direction X, which is the direction of relative movement between the magnetic scale 2 and the magnetic sensor device 3 . On the magnetic track 4, N poles and S poles are alternately arranged linearly at a predetermined pitch. In the magnetic encoder device 1, one of the magnetic scale 2 and the magnetic sensor device 3 is arranged on the fixed body side, and the other is arranged on the moving body side.

The magnetic sensor device 3 detects changes in the magnetic field formed on the surface of the magnetic scale 2 when moving relative to the magnetic scale 2 and outputs the absolute position of the magnetic scale 2 or the magnetic sensor device 3 . In the following description, a direction orthogonal to the first direction X is defined as a second direction Y, and a direction orthogonal to the first direction X and the second direction Y is defined as a third direction Z. Further, one side and the other side of the first direction X are defined as the X1 direction and the X2 direction, respectively, one side and the other side of the second direction Y are defined as the Y1 direction and the Y2 direction, respectively, and one side and the other side of the third direction Z are defined. are the Z1 direction and the Z2 direction, respectively. A third direction Z is a direction in which the magnetic scale 2 and the magnetic sensor device 3 face each other. The Z1 direction is the side on which the magnetic sensor device 3 is arranged, and the Z2 direction is the side on which the magnetic scale 2 is arranged.

(Magnetic sensor device)
The magnetic sensor device 3 includes a first case 6 and a second case 7 made of non-magnetic material, and a cable 8 extending from the first case 6 . The first case 6 and the second case 7 constitute the case of the magnetic sensor device 3 . In this embodiment, the first case 6 has a substantially rectangular parallelepiped shape with the first direction X as its longitudinal direction, and the second case 7 has a plate shape. The second case 7 is attached so as to close the concave space formed inside the first case 6 from the Z1 direction. As shown in FIG. 1, the cable 8 is held by a cable holding member 80 attached to the side surface of the first case 6 in the X1 direction and pulled out from the first case 6 in the X1 direction.

FIG. 2 is an exploded perspective view of the magnetic sensor device 3 as seen from the side of the facing surface 9 facing the magnetic scale 2 (Z2 direction), showing a state in which the magnetic sensor 10 and the aluminum sheet 13 are separated from the first case 6. . The first case 6 has a facing surface 9 that faces the magnetic scale 2 in the third direction Z. As shown in FIG. A magnetic sensor 10 is attached to the facing surface 9 and covered with an aluminum sheet 13 as a shield member. The magnetic sensor 10 includes a sensor substrate 11 such as a silicon substrate or a ceramic gray substrate, and a magnetoresistive element 12 formed on the surface of the sensor substrate 11 in the Z1 direction.

As shown in FIG. 2 , an opening 90 is formed in the facing surface 9 of the first case 6 . The opening 90 includes edge portions 90X1 and 90X2 that are opening edges facing each other in the first direction X, and edge portions 90Y1 and 90Y2 that are opening edges facing each other in the second direction Y. Sensor support portions 91 and 92 projecting toward the inside of the opening 90 are formed on the edge portions 90X1 and 90X2. A rectangular frame-shaped protruding portion 93 that is one size larger than the opening 90 is formed on the facing surface 9 of the first case 6 on the outer peripheral side of the opening 90 . A region between the projecting portion 93 and the opening 90 on the facing surface 9 is a stepped surface 94 that is recessed one step in the Z1 direction from the upper end surface (tip surface) of the projecting portion 93 . The Z2-direction surfaces of the sensor support portions 91 and 92 projecting inwardly of the opening 90 are provided at positions recessed further in the Z1 direction than the step surface 94 on the outer peripheral side of the opening 90 .

The magnetic sensor 10 is arranged inside the opening 90 with the surface on which the magnetoresistive element 12 is formed directed in the Z1 direction, and is fixed to the sensor support portions 91 and 92 from the Z2 direction. The magnetic sensor 10 is fixed to the sensor supports 91 and 92 with an adhesive. Further, the sensor substrate 11 is positioned and fixed in the second direction Y by abutting the tip surface of the positioning portion 95 projecting in the Y1 direction from the Y2-direction edge portion 90Y2 of the opening 90 . The aluminum sheet 13 is arranged on the inner peripheral side of the projecting portion 93 and attached so as to cover the magnetic sensor 10 and the step surface 94 . On the facing surface 9 of the first case 6 , the portion that protrudes most in the Z2 direction is the tip surface of the projecting portion 93 . When the magnetic sensor device 3 is assembled to the magnetic scale 2, the magnetoresistive element 12 and the magnetic scale 2 face each other with a predetermined gap therebetween.

3 and 4 are sectional views of the magnetic sensor device 3. FIG. 3 is a sectional view taken along line AA in FIG. 1, and FIG. 4 is a sectional view taken along line BB in FIG. 5 and 6 are exploded perspective views of the magnetic sensor device 3. FIG. 5 is an exploded perspective view seen from the Z1 direction, and FIG. 6 is an exploded perspective view seen from the Z2 direction. The first case 6 includes a rectangular bottom plate portion 61 having a facing surface 9 facing the Z2 direction, and a wall portion 62 rising from the outer peripheral edge of the bottom plate portion 61 in the Z1 direction. is formed in A notch is formed in the wall portion 62 in the X1 direction, and a cable holding member 80 is attached thereto. The second case 7 is fixed to the end of the wall portion 62 in the Z2 direction. As shown in FIG. 1, the second case 7 has two diagonal positions, one at the corner between the X1 direction and the Y1 direction of the wall portion 62 and the other at the corner between the X2 direction and the Y2 direction. It is screwed into a provided fixing hole 621 (see FIG. 5).

In the magnetic sensor device 3, the shield member 20, the first circuit board 31, and the second circuit board 32 are accommodated in this order between the first case 6 and the second case 7 while overlapping each other in the third direction Z. . The shield member 20 is fixed to the bottom plate portion 61 of the first case 6 from the Z1 direction. As shown in FIGS. 3 and 4, the first circuit board 31 is arranged to overlap the shield member 20 from the Z1 direction, and the second circuit board 32 is arranged to overlap the first circuit board 31 from the Z1 direction. placed in A first flexible printed board 40 is arranged between the first circuit board 31 and the shield member 20 , and a second flexible printed board 50 is arranged between the first circuit board 31 and the second circuit board 32 .

As shown in FIGS. 4 and 5, the first case 6 has a first stepped portion 63 formed inside the side surface in the X1 direction, and a first stepped portion 64 formed inside the side surface in the X2 direction. . The first step portions 63 and 64 are one step higher than the bottom plate portion 61 in the Z1 direction. Second step portions 65 and 66 are formed in the first case 6 on the Y1 direction side of the first step portions 63 and 64 (see FIGS. 5 and 7). The second stepped portions 65 and 66 are one step higher than the first stepped portions 63 and 64 in the Z1 direction. As shown in FIGS. 5 and 6, the first circuit board 31 has a fixed portion 311 projecting in the X1 direction from approximately the center of the edge in the X1 direction, and a fixed portion 311 extending in the X2 direction from approximately the center of the edge in the X2 direction. A projecting fixed portion 312 is formed. The second circuit board 32 is formed with a fixing portion 321 protruding from the edge in the X1 direction and a fixing portion 322 protruding from the edge in the X2 direction. The first circuit board 31 is fixed to the first case 6 by bringing the fixing portions 311 and 312 into contact with the first step portions 63 and 64 from the Z1 direction and screwing them. The second circuit board 32 is fixed to the first case 6 by bringing the fixing portions 321 and 322 into contact with the second step portions 65 and 66 from the Z1 direction and screwing them. The first circuit board 31 and the second circuit board 32 are positioned in the third direction Z by the first stepped portions 63 , 64 and the second stepped portions 65 , 66 .

The first flexible printed board 40 is a wiring member that connects the first circuit board 31 and the magnetic sensor 10 . As shown in FIG. 3, the first flexible printed board 40 includes a first portion 41 extending in the second direction Y between the first circuit board 31 and the shield member 20, and an end of the first portion 41 in the Y1 direction. The second portion 42 is folded back in the Y2 direction from the first portion 41 and overlaps the Z2 direction side of the first portion 41 , and the second portion 42 is folded in the Z2 direction side and passed through the through portion 21 formed in the shield member 20 to pass through the second portion 42 . A third portion 43 is provided that is pulled out to an opening 90 formed in the bottom plate portion 61 of the case 6 . As shown in FIGS. 5 and 6 , the first portion 41 is formed with a wide terminal portion 44 connected to the first circuit board 31 . The end of the third portion 43 in the Z2 direction is a terminal portion fixed to the sensor substrate 11 of the magnetic sensor 10 through the gap between the edge portion 90Y1 in the Y1 direction of the opening 90 and the sensor support portions 91 and 92. 45 are formed.

The second flexible printed board 50 is a wiring member that connects the first circuit board 31 and the second circuit board 32 . As shown in FIG. 3 , the second flexible printed circuit board 50 includes a first portion 51 extending in the second direction Y and a first portion 51 that is folded back in the Y1 direction from the end of the first portion 51 in the Y2 direction. A second portion 52 is provided that overlaps the Z1 direction side of the . The Y1-direction end of the first portion 51 is connected to the first circuit board 31 , and the Y1-direction end of the second portion 52 is connected to the second circuit board 32 .

The first circuit board 31 is provided with a signal processing circuit to which an analog signal output from the magnetoresistive element 12 of the magnetic sensor 10 is input, and a circuit such as an operational amplifier and a resistor that constitutes a circuit for amplifying the analog signal. device is installed. The second circuit board 32 includes a signal processing circuit for processing signals output from the first circuit board 31, a communication circuit for communicating with a host device, a power supply circuit, and the like. In this embodiment, the magnetic scale 2 is provided with an absolute track on which an absolute pattern is formed and an incremental track on which an incremental pattern is formed. It has a resistive element and a magnetoresistive element that reads an incremental pattern and outputs a signal. Therefore, many circuit elements are mounted on the first circuit board 31 in order to amplify the analog signals of these magnetoresistive elements. In the signal processing circuit of the second circuit board 32, the absolute value and the incremental value are obtained from the signal obtained by reading the absolute pattern and the signal obtained by reading the incremental pattern, and the absolute position of the magnetic scale 2 or the magnetic sensor device 3 is obtained. done.

(Shield member)
In this embodiment, the shield member 20 is arranged at the bottom of the first case 6 , and the first circuit board 31 and the second circuit board 32 are arranged in the Z1 direction of the shield member 20 . As a result, the shield member 20 is arranged between the magnetic sensor 10 attached to the facing surface 9 of the first case 6 and the first circuit board 31 , so that the magnetic sensor 10 is protected by the shield member 20 from the first magnetic field. It is shielded from the circuit board 31 and the second circuit board 32 . The shield member 20 is a metal plate, and permalloy is used in this embodiment. As shown in FIGS. 5 and 6, the shield member 20 includes a rectangular plate-like portion 22 elongated in the first direction X and a frame-like edge portion 23 formed on the outer peripheral edge of the plate-like portion 22. . The edge portion 23 has a shape in which four sides of the plate-like portion 22 are bent toward the magnetic sensor 10 (Z2 direction).

As shown in FIG. 4, in the shield member 20, the width of the plate-like portion 22 in the first direction X is larger than the width of the magnetic sensor 10 in the first direction X, and the edge portion 23 is It extends from both ends of X toward both sides of the magnetic sensor 10 in the first direction X. As shown in FIG. Further, as shown in FIG. 3, the shield member 20 has a plate-like portion 22 whose width in the second direction Y is larger than the width of the magnetic sensor 10 in the second direction Y, and the edge portion 23 It extends from both ends of the two Y directions toward both sides of the magnetic sensor 10 in the second Y direction. That is, the shield member 20 has a larger outer shape when viewed from the third direction Z than the outer shape of the magnetic sensor 10, and the magnetic sensor 10 is arranged inside the outer shape of the shield member 20 when viewed from the Z1 direction. The plate-like portion 22 is formed with a through portion 21 through which the third portion 43 of the first flexible printed circuit board 40 described above is passed. The penetrating portion 21 is formed in a slit shape extending in the first direction X, and extends in the first direction X at a position near the Y1 direction of the plate-like portion 22 .

The bottom plate portion 61 of the first case 6 has a facing surface 9 facing the side (Z2 direction) where the magnetic scale 2 is arranged, and has a flat bottom surface 67 facing the Z1 direction. The magnetic sensor 10 is fixed to the bottom plate portion 61 from the facing surface 9 side. On the other hand, the shield member 20 is fixed to the bottom plate portion 61 from the bottom surface 67 side. A groove portion 68 extending in a rectangular shape along the inner surface of the wall portion 62 is formed on the outer peripheral side of the bottom surface 67 . The edge portion 23 of the shield member 20 is inserted into the groove portion 68 . In addition, fixing protrusions 69 are formed at four corners of the bottom surface 67 so as to protrude in the Z1 direction. The shield member 20 is arranged so that the plate-like portion 22 abuts on the fixing convex portion 69 from the Z1 direction, and is fixed to the tip surface of the fixing convex portion 69 with an adhesive.

As shown in FIG. 5, the bottom plate portion 61 is formed with an opening 90 and a positioning convex portion 70 projecting from the bottom surface 67 toward the opposite side (Z1 direction) of the magnetic scale 2 on the outer peripheral side of the opening 90. ing. The positioning protrusions 70 are formed at two positions on the X1 direction side and the X2 direction side of the Y1 direction end of the opening 90 . The positioning protrusion 70 is inserted into the through portion 21 of the shield member 20 when fixing the shield member 20 to the bottom of the first case 6 .

7A and 7B are explanatory diagrams showing a method of assembling the magnetic sensor device 3. FIG. 7A is a perspective view of the magnetic sensor device 3 with the second case 7, the second circuit board 32, the second flexible printed board 50, the first circuit board 31, the first flexible printed board 40, and the shield member 20 removed. It is a diagram. 7(b) shows a state in which the shield member 20 is attached to FIG. 7(a), and FIG. 7(c) shows a state in which the first flexible printed circuit board 40 is further attached to FIG. 7(b). state. As shown in FIG. 7A, the magnetic sensor 10 is adhesively fixed to the sensor support portions 91 and 92 provided in the opening 90 from the Z2 direction. Further, the magnetic sensor 10 is positioned in the second direction Y by contacting the positioning portion 95 provided on the edge portion 90Y2 of the opening 90 in the Y2 direction.

When fixing the shield member 20 to the first case 6 , the shield member 20 is arranged on the bottom portion of the first case 6 after applying an adhesive to the tip surface of the fixing protrusion 69 . At that time, as shown in FIG. 7B, the positioning projections 70 formed on both sides of the opening 90 in the first direction X are inserted into the through-holes 21 of the shield member 20, and the edge of the shield member 20 is inserted. The portion 23 is inserted into the groove portion 68 . Then, the shield member 20 is positioned in the second direction Y by bringing the positioning protrusion 70 into contact with the edge of the through portion 21 in the Y2 direction. As a result, a state in which the penetrating portion 21 of the shield member 20 and the end portion of the opening 90 in the Y1 direction are overlapped in the third direction Z is formed. As shown in FIG. 7(c), the first flexible printed circuit board 40 is connected to the magnetic sensor 10 through the gap between the penetrating portion 21 and the opening portion 90. As shown in FIG.

As shown in FIGS. 5 and 6 , one end of a strip-shaped conductive member 24 is fixed to the shield member 20 . The conductive member 24 is a leaf spring made of metal. When fixing the shield member 20 to the first case 6, as shown in FIG. 7B, the other end of the conductive member 24 is screwed to the first stepped portion 64 of the first case 6 by a fixing screw 25. . A screw hole for screwing the conductive member 24 is formed in the first step portion 64 on the Y2 direction side of the screw hole for screwing the first circuit board 31 . When the conductive member 24 is screwed to the first step portion 63 , the shield member 20 is electrically connected to the first case 6 via the conductive member 24 and the fixing screw 25 . As a result, the shield member 20 can be reliably brought to the same potential as the first case 6 . Therefore, by grounding the first case 6 , the shield member 20 can be reliably grounded via the first case 6 .

(Main functions and effects of this embodiment)
As described above, in the magnetic encoder device 1 of the present embodiment, the first case 6 holding the magnetic sensor 10 having the magnetoresistive element 12 (magnetic sensor element) includes an electronic component for processing the signal of the magnetic sensor 10. The mounted first circuit board 31 and second circuit board 32 are accommodated to constitute the magnetic sensor device 3 including the magnetoresistive element 12 and the signal processing circuit. Thus, in constructing the magnetic sensor device 3 in which the signal processing circuit is incorporated in the sensor unit for detecting changes in the magnetic field, in the present embodiment, the sensor substrate 11 on which the magnetoresistive element 12 is mounted and the electronic parts are mounted. The shield member 20 is arranged between the first circuit board 31 and the second circuit board 32 . Thereby, the shield member 20 can reduce the magnetic influence from the electronic components mounted on the first circuit board 31 and the second circuit board 32 . In particular, in this embodiment, since a large number of electronic components such as operational amplifiers and resistors are mounted on the first circuit board 31 arranged on the side closer to the sensor board 11, the magnetic influence from these electronic components is shielded by the shield member 20. can be reduced by Therefore, even in a configuration in which not only the magnetoresistive element 12 but also the signal processing circuit is mounted on the magnetic sensor device 3 that moves relative to the magnetic scale 2, the magnetoresistive element is affected by the magnetic influence from the electronic components that make up the signal processing circuit. 12 can be prevented from deteriorating in position detection accuracy.

In this embodiment, when the shield member 20 and the magnetic sensor 10 are viewed from the side of the first circuit board 31 and the second circuit board 32, that is, from the Z1 direction, the outer shape of the sensor board 11 on which the magnetoresistive element 12 is formed is The outer shape of the shield member 20 is larger. Therefore, the magnetic influence from the Z1 direction can be reduced, and the magnetic influence from the electronic components mounted on the first circuit board 31 and the second circuit board 32 can be reduced. Further, in this embodiment, the entire circumference of the outer peripheral edge of the shield member 20 is bent toward the magnetic sensor 10 to form the edge portion 23 . Therefore, the magnetic influence from the outer peripheral side of the magnetic sensor 10, that is, both sides of the magnetic sensor 10 in the first direction X and both sides in the second direction Y can be reduced. In this embodiment, the entire circumference of the outer peripheral edge of the plate-like portion 22 of the shield member 20 is bent in the Z2 direction, but the edge portion 23 is formed only at one part of the outer peripheral edge of the plate-like portion 22. may be a part. For example, at least one side of the outer peripheral edge of the plate-like portion 22 may be bent in the Z2 direction.

The shield member 20 of this embodiment includes a through portion 21 through which the first flexible printed circuit board 40 connected to the magnetic sensor 10 is passed. Therefore, the first flexible printed circuit board 40 connecting the first circuit board 31 arranged in the Z1 direction of the shield member 2 and the magnetic sensor 10 arranged in the Z2 direction of the shield member 2 can be easily routed, and wiring can be performed. Space can be reduced. Moreover, since the penetrating portion 21 is a slit-shaped hole extending linearly, it is suitable for passing the first flexible printed circuit board 40 . Furthermore, since the penetrating portion 21 (hole) is formed instead of the notch, the magnetic field from the side where the first circuit board 31 and the second circuit board 32 are arranged is reduced compared to the case where the notch is formed. can reduce the impact.

In this embodiment, an opening 90 is formed in the bottom plate portion 61 of the first case 6, and on both sides of the opening 90 in the first direction X, there are positioned positioning electrodes protruding in the Z1 direction (that is, the side opposite to the magnetic scale 2). A convex portion 70 is formed. Therefore, when the shield member 20 is attached to the bottom plate portion 61 on the side opposite to the magnetic sensor 10, the positioning convex portion 70 can be inserted into the through portion 21 of the shield member 20 to position the shield member 20. . As a result, the shield member 20 can be positioned so that the penetrating portion 21 and the opening 90 overlap, and the magnetic sensor 10 is connected to the magnetic sensor 10 through the first flexible printed circuit board 40 at the place where the penetrating portion 21 and the opening 90 overlap. can do. Therefore, when the shield member 20 is attached, the positioning thereof can be easily performed, and the first flexible printed circuit board 40 can be easily routed.

The shield member 20 of this embodiment is fixed to the fixing convex portion 69 formed on the bottom plate portion 61 with an adhesive. Therefore, since there is no need to use fixing members such as screws, the number of parts can be reduced. Moreover, since it is not necessary to provide fixing structures such as fixing holes in the shield member 20 and the first case 6, the shapes of the shield member 20 and the first case 6 can be simplified.

The first case 6 of this embodiment has an opening 90 formed in the facing surface 9 to which the magnetic sensor 10 is fixed, and two locations protruding inside the opening 90 from two locations facing each other on the edge of the opening 90. The sensor substrate 11 of the magnetic sensor 10 is fixed to the sensor supports 91 and 92 at two locations. Such a fixing structure can suppress application of stress to the sensor substrate 11 via the first case 6 . Therefore, the deformation of the sensor substrate 11 can be suppressed, and the deterioration of the position detection accuracy due to the deformation of the sensor substrate 11 can be suppressed.

In this embodiment, the conductive member 24 is attached to the shield member 20, and the conductive member 24 is screwed to the first stepped portion 63 of the first case 6 by the fixing screw 25 when the shield member 20 is fixed to the first case 6. be done. As a result, the shield member 20 is electrically connected to the first case 6 via the conductive member 24 , so that the shield member 20 can be reliably grounded via the first case 6 . Therefore, since there is little possibility that electrical noise from the outside will be carried on the shield member 20, the magnetoresistive element 12 mounted on the magnetic sensor 10 and the electronic components mounted on the first circuit board 31 and the second circuit board 32 can suppress the influence of electrical noise on

REFERENCE SIGNS LIST 1 magnetic encoder device 2 magnetic scale 3 magnetic sensor device 4 magnetic track 6 first case 7 second case 8 cable 9 facing surface 10 magnetic sensor 11 Sensor substrate 12 Magnetoresistive element 13 Aluminum sheet 20 Shield member 21 Through portion 22 Plate-like portion 23 Edge 24 Conductive member 25 Fixing screw 31 First Circuit board 32 Second circuit board 40 First flexible printed board 41 First part 42 Second part 43 Third part 44, 45 Terminal part 50 Second flexible printed board , 51... First part 52... Second part 61... Bottom plate part 62... Wall part 63, 64... First step part 65, 66... Second step part 67... Bottom surface 68... Groove part 69 . . Fixing convex portion 70 . Step surface 95 Positioning portion 311, 312 Fixing portion 321, 322 Fixing portion 621 Fixing hole X First direction Y Second direction Z Third direction

Claims (7)

A magnetic sensor device that moves relative to a magnetic scale,
a magnetic sensor element;
a circuit board on which electronic components are mounted;
a case that holds the magnetic sensor element and the circuit board;
a shield member disposed between the magnetic sensor element and the circuit board;
When viewed from the circuit board side, the magnetic sensor element is positioned inside the contour of the shield member,
At least one side of the outer peripheral edge of the shield member is bent toward the magnetic sensor element ,
The magnetic sensor element is provided on a sensor substrate,
The shield member has a through portion through which a wiring member connected to the sensor substrate passes,
The case includes a bottom plate portion forming a facing surface facing the magnetic scale,
The bottom plate portion includes an opening and a positioning projection projecting to the side opposite to the magnetic scale on the outer peripheral side of the opening,
The sensor substrate is fixed to the bottom plate portion from the facing surface side,
The shield member is arranged on the side opposite to the sensor substrate with respect to the bottom plate portion, and is positioned at a position where the opening and the through portion overlap by inserting the positioning convex portion into the through portion. A magnetic sensor device characterized by : The wiring member is a flexible printed circuit board,
2. The magnetic sensor device according to claim 1 , wherein the penetrating portion is a slit extending linearly. The case includes an opening and two sensor support portions protruding inward from the opening from two opposing locations on the edge of the opening,
3. The magnetic sensor device according to claim 1 , wherein the sensor substrate is fixed to the two sensor support portions. 4. The magnetic sensor device according to claim 1 , wherein the shield member is fixed to the case with an adhesive. 5. The magnetic sensor device according to claim 1 , further comprising a conductive member having one end electrically connected to the shield member and the other end electrically connected to the case. 5. The magnetic sensor device according to claim 1 , wherein the electronic component constitutes a signal processing circuit to which a detection signal of the magnetic sensor element is input. the magnetic scale comprising a track in which N poles and S poles are alternately arranged in a straight line;
7. A position detecting device, comprising: the magnetic sensor device according to claim 1, which is movable relative to the magnetic scale in the direction in which the track extends.

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