Circuit board, motor unit, and fan

Abstract

The invention relates to a motor drive control circuit whose ESD resistance characteristics are improved while suppressing the increase in the area of ​​the circuit substrate. A circuit substrate (12) of a motor unit (10) equipped with a motor (11) is characterized in that it comprises: a substrate (130) having a main surface (131) and a back surface (132) on one side of a pair of opposite sides facing each other; a magnetic detection element (122) arranged in a predetermined area (AR) on the outer periphery of the substrate (130) on the main surface (131) and outputting a detection signal corresponding to the position of a rotor (14) of the motor (11); and a protection pattern (141) formed between the outer periphery of the substrate (130) and the magnetic detection element (122) in a predetermined area (AR) on the main surface (131) and supplied with a ground voltage.

Description

Technical Field

[0001] The present invention relates to a circuit substrate, a motor unit, and a fan, and in particular to a circuit substrate equipped with a motor drive control circuit for controlling the drive of a motor, a motor unit including the circuit substrate and a motor, and a fan including the motor unit and an impeller. Background Art

[0002] In a circuit board equipped with a motor drive control circuit for controlling the drive of a motor, it is necessary to prevent malfunction of the circuit caused by static electricity or damage to circuit elements caused by static electricity. As a general method for improving the ESD (Electro-Static Discharge) resistance of electronic circuits, the technology of mounting electronic components such as ESD protection elements on a circuit board is well known (see Patent Document 1).

[0003] Prior art literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2016-58745 Summary of the invention

[0005] Problems to be solved by the invention

[0006] However, in a circuit substrate equipped with a motor drive control circuit of an electronic device equipped with a small motor, it is not easy to install ESD protection elements, etc., because the area for installing electronic components is small and the freedom of wiring is low due to the size and shape constraints of the bearings supporting the output shaft of the motor.

[0007] For example, in a small axial flow fan, the following structure is provided: in a state in which a circuit substrate on which a stator constituting a motor and a motor drive control circuit for controlling the drive of the motor are installed is housed in a first shell arranged in the center part of the axial flow fan, and a rotor constituting the motor is housed in a second shell in a cylindrical shape formed integrally with an impeller, the second shell is arranged to cover the first shell.

[0008] The rotor of the axial flow fan having such a structure rotates due to the rotational force from the motor, whereby the second housing integrally formed with the impeller rotates, thereby generating wind.

[0009] On the circuit board of the axial flow fan, a magnetic detection element such as a Hall element is mounted to detect the magnetic flux of a magnet (permanent magnet) which is one of the components constituting the rotor in order to determine the rotational position of the rotor.

[0010] In order to detect the magnetic flux of the magnet with high precision, the magnetic detection element needs to be arranged near the magnet. The axial flow fan discussed by the inventors of this application is a structure in which the magnet is arranged along the inner wall of the second shell, so the magnetic detection element needs to be arranged on the outer peripheral side of the circuit substrate. Therefore, it is easy for human hands to touch the magnetic detection element, which is easy to cause electrostatic damage.

[0011] In order to prevent electrostatic destruction of the magnetic detection element, it is effective to provide an ESD protection element as described above. However, in order to provide an ESD protection element on the circuit substrate, it is necessary to enlarge the circuit substrate and expand the mounting area. If the circuit substrate becomes larger, the size of the first shell for accommodating the circuit substrate becomes larger, and the proportion of the first shell in the overall axial flow fan becomes larger. In an axial flow fan, the larger the first shell becomes, the narrower the area (space) where the wind flows generated by the rotation of the impeller, so there is a risk that sufficient air volume cannot be obtained to achieve the required cooling performance.

[0012] Thus, it is not easy to install an ESD protection element on a circuit board on which a motor drive control circuit for a small motor is mounted due to various restrictions. In particular, in the case of a motor drive control circuit for a small motor for vehicle use, the required level of ESD resistance is high, so there is a possibility that the size of the required ESD protection element will become larger, and it is extremely difficult to mount such a large ESD protection element on the circuit board without increasing the area of ​​the circuit board.

[0013] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to improve the ESD resistance characteristics of a motor drive control circuit while suppressing an increase in the area of ​​a circuit substrate.

[0014] A circuit substrate of a motor unit equipped with a motor according to a representative embodiment of the present invention is characterized in that it comprises: a substrate having one of a pair of opposite surfaces, namely a main surface, and the other of the pair of opposite surfaces, namely a back surface; a magnetic detection element, which is arranged in a predetermined area on the outer periphery of the substrate on the main surface and outputs a detection signal corresponding to the position of the rotor of the motor; and a metal component, which is formed between the periphery of the substrate and the magnetic detection element in the predetermined area on the main surface and is supplied with a ground voltage.

[0015] Effects of the Invention

[0016] According to the circuit board according to the present invention, it is possible to improve the ESD resistance characteristics of the motor drive control circuit while suppressing an increase in the area of ​​the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram showing the configuration of a fan according to Embodiment 1.

[0018] Figure 2A It is a plan view of the main surface side of the circuit board according to the first embodiment.

[0019] Figure 2B This is a plan view of the back surface side of the circuit board according to the first embodiment.

[0020] Figure 3 This is a diagram schematically showing a substrate housed in a housing portion on the circuit board according to the first embodiment.

[0021] Figure 4 yes Figure 1 An enlarged view of the peripheral portion of the magnetic detection element in FIG.

[0022] Figure 5A It is a plan view of the main surface side of the circuit board involved in the second embodiment.

[0023] Figure 5B It is a plan view of the back surface side of the circuit board involved in Embodiment 2.

[0024] Figure 6 This is a diagram schematically showing the structure of a through-hole portion on a circuit board according to the second embodiment. DETAILED DESCRIPTION

[0025] 1. Overview of implementation methods

[0026] First, a summary of a representative embodiment of the invention disclosed in this application will be described. In the following description, as an example, reference numerals on the drawings corresponding to the constituent elements of the invention are given in parentheses.

[0027] [1] A representative embodiment of the present invention involves a circuit substrate (12, 12A) of a motor unit (10) equipped with a motor (11), characterized in that it comprises: a substrate (130) having one of a pair of opposite surfaces, namely a main surface (131) and the other of the pair of opposite surfaces, namely a back surface (132); a magnetic detection element (122) which is arranged in a predetermined area (AR) on the outer peripheral side of the substrate on the main surface and outputs a detection signal corresponding to the position of the rotor (14) of the motor; and a metal member (141, 144) which is formed between the periphery of the substrate and the magnetic detection element in the predetermined area of ​​the main surface and is supplied with a ground voltage.

[0028] [2] In the above-mentioned circuit substrate (12), the metal member may include a first wiring pattern (141) made of metal formed along the outer periphery (136, 135a) of the substrate in the predetermined region of the main surface.

[0029] [3] In the above-mentioned circuit substrate, an insulating film may not be formed on the surface of the first wiring pattern.

[0030] [4] The above-mentioned circuit substrate may also further include: a second wiring pattern (142) made of metal, which is supplied with the ground voltage and is formed on the back side; and at least one via (143, 143_1, 143_2) (via), which penetrates the main surface and the back side and connects the first wiring pattern and the second wiring pattern.

[0031] [5] In the above-mentioned circuit substrate (12), there may also be a grounding pattern (137) made of metal, which is supplied with the grounding voltage and is formed on the main surface, the first wiring pattern is strip-shaped, one end (141a) of the first wiring pattern is connected to the grounding pattern, and at least one of the vias is formed on the other end (141b) side of the first wiring pattern.

[0032] [6] In the above-mentioned circuit substrate (12A), there may also be a grounding pattern (142A) made of metal, which is supplied with the grounding voltage and is formed on the back side, and the metal component is a through hole portion (144) including a metal film (146) formed on the inner wall surface of the substrate defined by a through hole (145) penetrating the main surface and the back side, and the metal film is connected to the grounding pattern.

[0033] [7] In the above-mentioned circuit substrate, it is also possible to include a plurality of the through-hole portions, and the plurality of the through-hole portions are arranged in parallel along the outer periphery (135a, 136) of the substrate in the predetermined area.

[0034] [8] In the above circuit board, the metal film may extend from an inner wall surface of the substrate defined by the through hole to the main surface.

[0035] [9] In the above-mentioned circuit substrate, it is also possible that: the substrate has a main portion (134) and a protrusion (135) protruding outward from the main portion, the predetermined area is an area on the main surface including the protrusion, and the metal component is arranged along the outer periphery (135a) of the protrusion.

[0036]

[10] A motor unit (10) according to a representative embodiment of the present invention is characterized in that it comprises: the above-mentioned circuit substrate (12, 12A), the motor (11), and a storage portion (43) having a cylindrical side wall portion (43a) for storing the substrate, the outer periphery of the main portion of the substrate is surrounded by the side wall portion (43a), and at least a portion of the outer periphery of the protruding portion of the substrate is not surrounded by the side wall portion.

[0037]

[11] A fan (1) according to a typical embodiment of the present invention is characterized by comprising: the above-mentioned motor unit (10); and an impeller (30) configured to be rotatable by the rotational force of the motor.

[0038] 2. Specific examples of implementation methods

[0039] Hereinafter, specific examples of the embodiments of the present invention will be described with reference to the drawings. In addition, in the following description, the same reference numerals are given to common components in each embodiment, and repeated descriptions are omitted. In addition, it should be noted that the drawings are schematic drawings, and sometimes the dimensional relationship of each element, the ratio of each element, etc. are different from the actual. Sometimes, the drawings also contain parts with different dimensional relationships and ratios.

[0040] Implementation Method 1

[0041] Figure 1 1 is a diagram showing a configuration of a fan according to Embodiment 1. In this diagram, a cross-sectional shape of a fan 1 according to Embodiment 1 is shown.

[0042] The fan 1 is a device that generates wind by rotating an impeller. The fan 1 is, for example, an axial flow fan. The fan 1 can be used as one of cooling devices that discharges heat generated inside a device to the outside and cools the inside of the device.

[0043] like Figure 1 As shown, the fan 1 includes a motor unit 10, an impeller 30, and a housing 40. The housing 40 is a casing that accommodates the motor unit 10 and is made of, for example, resin.

[0044] The housing 40 has a storage portion 43 and an outer wall portion 44. The storage portion 43 is formed, for example, in a bottomed cylindrical shape. Specifically, the storage portion 43 has a cylindrical side wall portion 43a, and the circuit board 12 is stored inside the side wall portion 43a as described later. The storage portion 43 is arranged at the center of the housing 40.

[0045] The outer wall portion 44 is connected to the housing portion 43 and is disposed coaxially with the side wall portion 43a of the housing portion 43. The outer wall portion 44 has a cylindrical shape having a larger diameter than the side wall portion 43a of the housing portion 43. For example, the outer wall portion 44 and the housing portion 43 are formed integrally.

[0046] like Figure 1 As shown, the impeller 30 is arranged inside the outer wall portion 44. The outer wall portion 44 functions as a protection portion for protecting the impeller 30. Between the storage portion 43 and the outer wall portion 44, openings 41 and 42 are formed for passing wind generated by the rotation of the impeller 30.

[0047] The impeller 30 is a component that generates wind by rotating. The impeller 30 is configured to be rotatable by the rotational force of the motor 11. Specifically, the impeller 30 includes a housing 31 and a wing 32. The housing 31 is a cylindrical housing that stores the rotor 14 described later. The wing 32 is a functional part that generates wind and is formed by protruding in the radial direction from the outer peripheral surface of the housing 31.

[0048] The motor unit 10 includes a motor 11 that generates a rotational force for rotating the impeller 30 , and a circuit board 12 on which a motor drive control circuit for controlling the driving of the motor 11 is formed.

[0049] The motor 11 is, for example, a single-phase brushless DC motor. The motor 11 includes a stator 13 and a rotor 14. The stator 13 includes a stator core 15, an insulator 16, a coil 17, and a bearing sleeve 20 (shell). The rotor 14 includes an output shaft (shaft) 18, a magnet (permanent magnet) 21, and a rotor yoke 22. The output shaft 18 is connected to the storage portion 31 of the impeller 30.

[0050] The rotor 14 is housed in the housing portion 31 of the impeller 30. Specifically, Figure 1 As shown, the output shaft 18 is arranged in the center part of the cylindrical housing portion 31 supported by the bearing 19, and the bearing 19 is covered by the bearing sleeve 20. In addition, on the inner wall surface 310 side of the cylindrical housing portion 31, a ring-shaped magnet 21, for example, is arranged, and the rotor yoke 22 is arranged between the magnet 21 and the inner wall surface 310 of the housing portion 31.

[0051] The motor drive control circuit is implemented by mounting a plurality of electronic components such as the magnetic detection element 122 and the motor drive control IC (Integrated Circuit) 121 on the circuit board 12 and interconnecting them through wiring.

[0052] The magnetic detection element 122 is a component for detecting the position of the rotor 14 of the motor 11 , and is, for example, a Hall element, a Hall IC, etc. The magnetic detection element 122 detects the position of the rotor 14 of the motor 11 , and generates and outputs a detection signal corresponding to the detected position of the rotor 14 .

[0053] The motor drive control IC 121 is a semiconductor integrated circuit that supplies a signal generated based on a detection signal output from the magnetic detection element 122 to the coil 17 to drive the motor 11 and generates a periodic signal (for example, an FG signal) according to the rotation speed of the motor 11 .

[0054] The motor drive control circuit supplies current to the coil 17 and periodically switches the direction of the current flow, thereby rotating the rotor 14. This causes the impeller 30 connected to the output shaft 18 of the rotor 14 to rotate, thereby generating wind.

[0055] As described above, the motor drive control circuit is realized by mounting various electronic components on the circuit board 12. The circuit board 12 has various configurations for improving the ESD resistance characteristics of the motor drive control circuit. The circuit board 12 will be described in detail below.

[0056] Figure 2A , 2B This is a diagram showing the configuration of the circuit board 12 according to the first embodiment.

[0057] exist Figure 2A , a top view of the main surface 131 side of the circuit substrate 12 (substrate 130) is shown. Figure 2B , a plan view of the back surface 132 side of the circuit board 12 (substrate 130 ) is shown.

[0058] Figure 2A , 2B The circuit substrate 12 shown includes a substrate 130 and various electronic components mounted on the substrate 130. The circuit substrate 12 is a mounting substrate (Printed Circuit Board) as follows: electronic components such as a motor drive control IC and a magnetic detection element 122 are mounted on the substrate 130, and the various electronic components are connected to each other through a wiring pattern formed on the substrate 130, thereby realizing a motor drive control circuit.

[0059] The substrate 130 is, for example, a printed circuit board (PWB) on which a plurality of wiring patterns made of a metal thin film (such as copper foil) are formed. Figure 2A , 2B As shown, substrate 130 has a pair of oppositely facing surfaces, namely a main surface 131 and the other of the pair of opposite surfaces, namely a back surface 132. Substrate 130 is, for example, a double-layer substrate (double-sided substrate) in which main surface 131 is a first wiring layer and back surface 132 is a second wiring layer.

[0060] The substrate 130 is formed in a circular ring shape when viewed from above. Specifically, a circular through hole 133 is formed in the center portion of the substrate 130 which has a circular shape when viewed from above and passes through the main surface 131 and the back surface 132. The through hole 133 is a hole for setting a part of the motor 11. Specifically, Figure 1 As shown, when the fan 1 (motor unit 10 ) as a product is assembled, the output shaft 18 of the motor 11 , the bearing 19 , and the bearing housing 20 are arranged in the through hole 133 of the base plate 130 .

[0061] In addition, Figure 2A , 2B In FIG. 1 , the axis line of the output shaft 18 when the fan 1 is assembled is indicated by the reference symbol “S”.

[0062] The substrate 130 has a main portion 134 and a protruding portion 135 protruding outward from the main portion 134. A plurality of electronic components (such as the motor drive control IC 121) and a wiring pattern constituting a motor drive control circuit are arranged in the main portion 134. As described later, a portion of electronic components constituting the motor drive control circuit, such as the magnetic detection element 122, are arranged in the protruding portion 135.

[0063] like Figure 2A , 2B As shown, the substrate 130 is received in the receiving portion 43 of the housing 40 .

[0064] Specifically, the substrate 130 is arranged in the housing portion 43 in a state where the main portion 134 is covered by the housing portion 43 and the protruding portion 135 of the substrate 130 is exposed from the housing portion 43 .

[0065] Figure 3 1 is a diagram schematically showing a substrate 130 housed in a housing portion 43. Figure 1 The positional relationship between the storage portion 43 and the substrate 130 when viewed in a direction P perpendicular to the axis S in FIG.

[0066] like Figure 3 As shown, the main portion 134 of the substrate 130 is disposed in the housing portion 43. On the other hand, the protrusion 135 of the substrate 130 is disposed in a recessed portion 43b formed by recessing in a direction parallel to the axis S in the side wall portion 43a of the housing portion 43.

[0067] Thus, the outer periphery 134a of the main portion 134 of the substrate 130 is configured to be surrounded by the side wall portion 43a of the storage portion 43, and at least a portion of the outer periphery 135a of the protrusion 135 of the substrate 130 is not surrounded by the side wall portion 43a of the storage portion 43 and is exposed to the outside of the storage portion 43.

[0068] In order to efficiently detect the magnetic flux of the magnet 21 of the rotor 14, as Figure 1 As shown in FIG. 1 , when viewed from the axis S direction of the output shaft 18, the magnetic detection element 122 is arranged in a region overlapping with the magnet 21 (for example, directly below the magnet 21). More specifically, as shown in FIG. Figure 2A As shown, the magnetic detection element 122 is arranged in a predetermined region AR on the main surface 131 of the substrate 130 , on the outer periphery 136 side of the substrate 130 .

[0069] Here, the so-called predetermined area AR is, for example, Figure 2A As shown in FIG. 1 , the area on the main surface 131 including the protrusion 135 is shown. Figure 2A, as an example, a case where two protrusions 135 are provided on the substrate 130 and one of the protrusions 135 is included in the predetermined area AR is shown.

[0070] In addition, all of the magnetic detection element 122 may be disposed on the protrusion 135, or a part of the magnetic detection element 122 may be disposed. Figure 2A , as an example, a case where the magnetic detection element 122 is arranged from the protruding portion 135 to the main portion 134 is shown.

[0071] Electronic components other than the magnetic detection element 122 and main wiring patterns are arranged in the main portion 134. For example, in the main portion 134 of the main surface 131, the motor drive control IC 121 is arranged, and a wiring pattern 137 to which a ground voltage is supplied (hereinafter referred to as a "ground pattern") is formed.

[0072] Furthermore, a metal member 141 for ESD protection of the motor drive control circuit is provided on the substrate 130. The metal member 141 is formed between the outer periphery 136 of the substrate 130 and the magnetic detection element 122 in a predetermined region AR of the main surface 131 and is connected to the ground pattern 137.

[0073] For example, Figure 2A As shown in FIG. 1 , the metal member 141 is a first wiring pattern made of metal formed along the periphery of the substrate 130 in a predetermined area AR of the main surface 131. Hereinafter, the metal member 141 is also referred to as a "protection pattern 141". Figure 2A In order to facilitate understanding, the protection pattern 141 and the ground pattern 137 are shaded.

[0074] The protection pattern 141 is formed in a strip shape, for example. That is, the protection pattern 141 is formed of a strip-shaped metal thin film formed on the main surface 131 along a portion of the outer periphery 136 of the substrate 130. One end 141a of the protection pattern 141 is connected to the ground pattern 137. Thus, the ground voltage is supplied to the protection pattern 141 via the ground pattern 137.

[0075] Here, the protection pattern 141 is preferably formed so as to surround at least the magnetic detection element 122 from the outside in a predetermined area AR on the main surface 131. More preferably, for example Figure 2A As shown, the protection pattern 141 is formed in a predetermined area AR on the main surface 131 so as to surround the magnetic detection element 122 and the wiring patterns 138_1 and 138_2 connected to the magnetic detection element 122 from the outside.

[0076] Preferably, no insulating film is formed on the surface of the protective pattern 141. For example, in the manufacturing process of the printed circuit board as the circuit board 12, no solder resist for protecting the surface of the board is applied on the protective pattern 141. Thus, the insulation resistance value of the protective pattern 141 against static electricity can be reduced.

[0077] like Figure 2B As shown in FIG. 1 , a wiring pattern 142 made of metal to which a ground voltage is supplied is formed as a second wiring pattern on the back surface 132 of the substrate 130. The wiring pattern 142 is, for example, a solid pattern. Hereinafter, the wiring pattern 142 is referred to as a "ground pattern 142". Figure 2B In order to facilitate understanding, the ground pattern 142 is shaded.

[0078] The ground pattern 142 and the protection pattern 141 may also be connected through at least one via 143 that penetrates the main surface 131 and the back surface 132. Figure 2A , Figure 2B , as an example, a case where two via holes 143_1 and 143_2 are formed in the substrate 130 is shown.

[0079] At least one of the via holes 143 may be formed on the other end portion 141b side of the protection pattern 141. Figure 2A , Figure 2B As shown, it is also possible that: among the two vias 143_1 and 143_2, the via 143_1 is formed on the side of the end 141a of the protection pattern 141 connected to the ground pattern 137, and the via 143_2 is formed on the side of the end 141b of the protection pattern 141 on the opposite side of the end 141a connected to the ground pattern 137.

[0080] According to the circuit board 12 having the above-mentioned structure, the following effects are obtained.

[0081] Figure 4 yes Figure 1 An enlarged view of the peripheral portion of the magnetic detection element 122 in FIG.

[0082] In the fan 1 according to the first embodiment, Figure 2A , Figure 2B As shown, the main part of the substrate 130 is formed as small as possible and arranged in the storage part 43 of the housing 40, and the magnetic detection element 122 is arranged on the protrusion 135 formed by protruding from the main part of the substrate 130, and the protrusion 135 is exposed to the outside of the storage part 43.

[0083] According to this configuration, the magnetic flux of the magnet 21 can be detected with high precision by the magnetic detection element 122 while the installation area of ​​the substrate 130 is minimized, and a dustproof effect can be expected by covering the portion (main portion 134) other than the protrusion 135 of the substrate 130 by the side wall portion 43a of the storage portion 43.

[0084] Furthermore, the main portion 134 on which the plurality of electronic components such as the motor drive control IC 121 are mounted is surrounded by the side wall portion 43 a of the storage portion 43 , so that it is difficult for charged objects such as human hands to touch it, and electrostatic damage to the electronic components is unlikely to occur.

[0085] On the other hand, Figure 4 As shown, the protrusion 135 of the substrate 130 on which the magnetic detection element 122 is mounted is not surrounded by the side wall portion 43a of the storage portion 43, and is exposed from the storage portion 43, so it is easy for a charged object 60 such as a hand to touch it. Therefore, the magnetic detection element 122 arranged on the protrusion 135 is easily electrostatically destroyed, resulting in a decrease in the ESD resistance characteristics of the motor drive control circuit.

[0086] Therefore, in the circuit substrate 12 involved in embodiment 1, the magnetic detection element 122 is arranged in a predetermined area AR on the side of the periphery 136 on the main surface 131 of the substrate 130, and the protection pattern 141, which is a metal component supplied with a ground voltage, is arranged between the periphery 136 of the substrate 130 and the magnetic detection element 122 in the predetermined area AR along the periphery 136 of the substrate 130.

[0087] Therefore, if Figure 4 As shown, even when a charged body 60 such as a human hand approaches the protrusion 135 (predetermined area AR) of the substrate 130 or when the charged body 60 contacts the protrusion 135, discharge occurs between the charged body 60 and the protection pattern 141 having an impedance (resistance value) lower than that of the magnetic detection element 122, thereby preventing electrostatic destruction of electronic components such as the magnetic detection element 122 that are arranged on the protrusion 135 (predetermined area AR).

[0088] Thus, according to the circuit board 12 involved in Embodiment 1, the ESD resistance characteristics of the motor drive control circuit can be improved without separately providing electronic components such as ESD protection elements. That is, according to the circuit board 12, the ESD resistance characteristics of the motor drive control circuit can be improved while suppressing the increase in the area of ​​the circuit board.

[0089] Furthermore, since no insulating film is formed on the surface of the protection pattern 141, the insulation resistance value of the protection pattern 141 against static electricity can be further reduced, so that the ESD resistance characteristic of the motor drive control circuit can be further improved.

[0090] In addition, in the circuit substrate 12 according to the first embodiment, the ground pattern 142 is formed as the second wiring pattern on the back surface of the substrate 130, and the protection pattern 141 and the ground pattern 142 are connected through at least one via 143, so that the resistance value of the protection pattern 141 can be further reduced. Thus, the ESD resistance characteristics of the motor drive control circuit can be further improved.

[0091] Furthermore, the protection pattern 141 is formed by a strip-shaped wiring pattern, one end 141 a of the protection pattern 141 is connected to the ground pattern 137 , and at least one via 143 is formed on the other end 141 b side of the protection pattern 141 .

[0092] Thus, the other end 141b side of the protection pattern 141 is connected to the grounding pattern 142 on the back side via the via 143, so even if a crack occurs on the substrate 130 during processing of the outer shape of the substrate 130 and the protection pattern 141 is broken, the ESD protection function of the other end 141b side of the protection pattern 141 can be prevented from being lost.

[0093] Implementation Method 2

[0094] Figure 5A , 5B This is a diagram showing the configuration of a circuit board 12A according to the second embodiment.

[0095] exist Figure 5A , a top view of the main surface 131 side of the circuit substrate 12A (substrate 130) is shown. Figure 5B , a plan view of the back surface 132 side of the circuit board 12A (board 130) is shown.

[0096] The circuit substrate 12A according to the second embodiment is different from the circuit substrate 12 according to the first embodiment in that it has a through hole portion 144 as a metal member for ESD protection of the motor drive control circuit instead of the protection pattern 141, but is the same as the circuit substrate 12 according to the first embodiment in other respects.

[0097] Specifically, if Figure 5A , 5B As shown, the circuit substrate 12A includes: a ground pattern 142A formed on the back surface 132 of the substrate 130; and at least one through hole portion 144 connected to the ground pattern 142A and formed in a predetermined area AR of the substrate 130 including the protrusion 135.

[0098] In addition, Figure 5A , 5BIn the example, six through-hole portions 144_1 to 144_6 are formed, but the number of through-hole portions 144 formed in the substrate 130 is not particularly limited. Figure 5B In the figure, the ground pattern 142A is shaded for easier understanding.

[0099] The ground pattern 142A is, for example, a solid pattern and is formed on the back surface 132 of the substrate 130 so as to overlap at least a portion of the predetermined region AR.

[0100] Figure 6 1 is a diagram schematically showing the configuration of the through hole portion 144. In this diagram, a cross-sectional structure of a region of the substrate 130 where the through hole portion 144 is formed is schematically shown.

[0101] like Figure 6 As shown, the through hole portion 144 includes: a through hole 145 that penetrates the main surface 131 and the back surface 132 of the substrate 130; and a metal film 146 that is formed on the inner wall surface of the substrate 130 defined (drawn) by the through hole 145. The metal film 146 is formed of, for example, the same metal material as the various wiring patterns formed on the substrate 130.

[0102] Metal film 146 is connected to ground pattern 142A on the back surface 132 side of through hole 145. Specifically, metal film 146 extends from the inner wall surface of substrate 130 defined by through hole 145 to back surface 132 and is connected to ground pattern 142A.

[0103] In addition, the metal film 146 extends from the inner wall surface of the substrate 130 defined by the through hole 145 to the main surface 131. Figure 6 As shown, the metal film 146 is exposed on the main surface 131 .

[0104] like Figure 5A , 5B As shown, the through-hole portions 144_1 to 144_6 are arranged in parallel along the outer periphery 136 (outer periphery 135a of the protrusion 135) of the substrate 130 in a predetermined area AR of the substrate 130. At this time, the through-hole portions 144_1 to 144_6 are preferably formed in the predetermined area AR on the main surface 131 in such a manner that the magnetic detection element 122 is surrounded from the outside by an imaginary line connecting the through-hole portions 144_1 to 144_6.

[0105] For example Figure 5A As shown, it is more preferable to form a predetermined area AR on the main surface 131, through an imaginary line connecting the through-hole portions 144_1 to 144_6, to surround not only the magnetic detection element 122 but also the wiring patterns 138_1, 138_2, etc. connected to the magnetic detection element 122 from the outside.

[0106] As described above, in the circuit substrate 12A involved in embodiment 2, a grounding pattern 142A is formed on the back side 132 of the substrate 130, and a through hole 145 is formed between the outer periphery 136 of the substrate 130 and the magnetic detection element 122 in a predetermined area AR, and a metal film 146 serving as a metal component is formed on the inner wall surface of the substrate 130 defined by the through hole 145, thereby connecting the metal film 146 and the grounding pattern 142A to each other.

[0107] Therefore, similar to the circuit substrate 12 involved in embodiment 1, even when a charged body 60 such as a human hand approaches the protrusion 135 (predetermined area AR) of the substrate 130 or when the charged body 60 contacts the protrusion 135, discharge occurs between the charged body 60 and the metal film 146 having an impedance (resistance value) lower than that of the magnetic detection element 122, thereby preventing electrostatic destruction of electronic components such as the magnetic detection element 122 arranged on the protrusion 135 (predetermined area AR).

[0108] Therefore, according to the circuit board 12A according to the second embodiment, similarly to the circuit board 12 according to the first embodiment, it is possible to improve the ESD resistance characteristics of the motor drive control circuit while suppressing an increase in the area of ​​the circuit board.

[0109] In addition, in a predetermined area AR of the substrate 130, a plurality of through-hole portions 144 are arranged in parallel along the outer periphery 136 of the substrate 130 (the outer periphery 135a of the protrusion 135), whereby the magnetic detection element 122 is surrounded from the outside by the plurality of through-hole portions 144, thereby more effectively preventing electrostatic destruction of the magnetic detection element 122, etc., and improving the ESD resistance characteristics of the motor drive control circuit.

[0110] In addition, if Figure 6 As shown, in the circuit substrate 12A, the metal film 146 of the through hole portion 144 is formed to extend from the inner wall surface of the substrate 130 defined by the through hole 145 to the main surface 131 and be exposed on the main surface 131 .

[0111] Thus, even when the charged body 60 approaches (or contacts) the main surface 131 of the substrate 130, it is easy to discharge from the charged body 60 relative to the metal film 146, which can improve the ESD resistance characteristics of the motor drive control circuit. In addition, the through hole portion 144 can be formed by the same manufacturing process as the via hole in the multilayer substrate.

[0112] 《Expansion of implementation methods》

[0113] As mentioned above, the invention completed by the present inventors has been specifically described based on the embodiment, but it goes without saying that the present invention is not limited to this, and various changes can be made within the scope not departing from the gist of the invention.

[0114] For example, in the above embodiment, the case where the outer shape of the substrate 130 is a circular shape when viewed from above is illustrated, but the present invention is not limited thereto. For example, it may be a rectangular shape (e.g., a quadrilateral shape) or other shapes. In addition, the case where the through hole 133 formed in the substrate 130 is a circular shape when viewed from above is illustrated, but the present invention is not limited thereto. For example, it may be a rectangular shape (e.g., a quadrilateral shape).

[0115] Furthermore, the through hole 133 is not limited to the central portion of the substrate 130, and may be formed at other positions of the substrate 130. In addition, the through hole 133 may not be formed on the substrate 130. In this case, as long as it can be Figure 2A , 2B The output shaft 18 , the bearing 19 , and the bearing sleeve 20 may be placed in the region corresponding to the through hole 133 .

[0116] In addition, in the above embodiment, the circuit substrate 12, 12A is exemplified as a circuit substrate for a single-phase brushless motor, but the present invention is not limited thereto. For example, the protective pattern 141 and the through hole portion 144 as metal components may be similarly formed in a circuit substrate for a multi-phase (e.g., three-phase) brushless motor.

[0117] Furthermore, in the above embodiment, the case where the magnetic detection element 122 is a Hall element is exemplified, but the magnetic detection element 122 may be a Hall IC including a Hall element and other peripheral circuits.

[0118] Furthermore, although the case where the substrate 130 is a double-sided substrate is exemplified, the substrate 130 may be a multi-layer substrate having three or more wiring layers.

[0119] In addition, the configuration of the fan 1 is not limited to Figure 1 For example, as long as the function as a fan can be realized by using the circuit substrates 12 and 12A, the components may be added or changed.

[0120] In the above-described embodiment, the shape of the wiring pattern formed on the circuit substrate 12, 12A, the shape of the package of the electronic components such as the motor drive control IC 121, etc. are not limited to the above-described embodiment. Figure 2A , 2B As long as the purpose can be achieved, various shapes can be adopted.

[0121] In the above embodiment, the electronic component disposed on the protrusion 135 is the magnetic detection element 122, but electronic components other than the magnetic detection element 122 may be disposed on the protrusion 135. Similarly, electrostatic destruction of the electronic component disposed on the protrusion 135 can be prevented.

[0122] In the first embodiment, the case where two via holes 143_1 and 143_2 are formed in the substrate 130 is exemplified, but the present invention is not limited thereto, and three or more via holes 143 may be formed.

[0123] In addition, in Embodiment 2, the case where the metal film 146 extends from the inner wall surface of the substrate 130 defined by the through hole 145 to the main surface 131 is illustrated, but the present invention is not limited thereto. For example, in the case where the required ESD resistance characteristics are satisfied, the metal film 146 may be formed only on the inner wall surface of the substrate 130 defined by the through hole 145, and not formed on the main surface 131. However, the metal film 146 needs to be connected to the ground pattern 142A formed on the back surface 132.

[0124] Reference numerals list

[0125] 1: fan, 10: motor unit, 11: motor, 12, 12A: circuit board, 13: stator, 14: rotor, 15: stator core, 16: insulator, 17: coil, 18: output shaft, 19: bearing, 20: bearing sleeve, 21: magnet, 22: rotor yoke, 30: impeller, 31: storage part, 32: wing part, 40: housing, 41, 42: opening, 43: storage part, 43a: side wall part of storage part 43, 43b: recessed part, 44: outer wall part, 60: charged body, 121: motor drive control IC, 122: magnetic detection element, 130: substrate, 131: main surface, 132: back surface, 133: through hole, 134: main part, 134a : The periphery of the main portion 134, 135: The protruding portion, 135a: The periphery of the protruding portion 135, 136: The periphery of the substrate 130, 137: The ground pattern, 141: The protection pattern (a metal component, an example of a first wiring pattern), 141a: An end portion of one side of the protection pattern 141, 141b: An end portion of the other side of the protection pattern 141, 142, 142A: The ground pattern (an example of a second wiring pattern), 143, 143_1, 143_2: A via, 144, 144_1 to 144_6: A through hole portion, 145: A through hole, 146: A metal film, AR: A predetermined area, 138_1, 138_2: A wiring pattern, 310: The inner wall surface of the storage portion 31.

Claims

1. A circuit board, which is a circuit board of a motor unit equipped with a motor, comprising: A substrate having a main surface on one side of a pair of opposite surfaces and a back side on the other side of the pair of opposite surfaces; a magnetic detection element disposed on the main surface in a predetermined area on the outer peripheral side of the substrate and outputting a detection signal corresponding to the position of the rotor of the motor; a metal member formed between the periphery of the substrate and the magnetic detection element in the predetermined region of the main surface, to which a ground voltage is supplied, and comprising a first wiring pattern made of metal formed along the periphery of the substrate in the predetermined region of the main surface; a second wiring pattern made of metal, supplied with a ground voltage and formed on the back surface; a ground pattern made of metal, to which a ground voltage is supplied, formed on the main surface, and connected to one end of the first wiring pattern; and at least one via hole that penetrates the main surface and the back surface, connects the first wiring pattern and the second wiring pattern, and is formed on the other end side of the first wiring pattern, The first wiring pattern is in a strip shape.

2. The circuit substrate according to claim 1, characterized in that: On the surface of the first wiring pattern, no insulating film is formed.

3. A circuit substrate, which is a circuit substrate of a motor unit equipped with a motor, comprising: A substrate having a main surface on one side of a pair of opposite surfaces and a back side on the other side of the pair of opposite surfaces; a magnetic detection element disposed on the main surface in a predetermined area on the outer peripheral side of the substrate and outputting a detection signal corresponding to the position of the rotor of the motor; a metal member formed between the outer periphery of the substrate and the magnetic detection element in the predetermined region of the main surface and supplied with a ground voltage; and A ground pattern made of metal, to which a ground voltage is supplied, is formed on the back surface, The metal member is a through hole portion including a metal film formed on an inner wall surface of the substrate defined by a through hole penetrating the main surface and the back surface, The metal film is connected to the ground pattern, The circuit substrate includes a plurality of through-hole portions. The plurality of through-hole portions are arranged in parallel along the outer circumference of the substrate in the predetermined region.

4. The circuit substrate according to claim 3, characterized in that: The metal film extends from an inner wall surface of the substrate defined by the through hole to the main surface.

5. The circuit substrate according to any one of claims 1 to 4, characterized in that: The substrate has a main portion and a protruding portion protruding outward from the main portion. The predetermined area is an area on the main surface including the protrusion, The metal member is arranged along the outer circumference of the protrusion.

6. A motor unit, characterized in that: have: The circuit substrate according to any one of claims 1 to 4, the motor, and a storage portion having a cylindrical side wall portion for storing the substrate, The substrate has a main portion and a protruding portion protruding outward from the main portion. The outer periphery of the main portion of the substrate is surrounded by the side wall portion, At least a portion of an outer periphery of the protruding portion of the substrate is not surrounded by the side wall portion.

7. A motor unit, characterized in that: have: According to the circuit substrate of claim 5, the motor, and a storage portion having a cylindrical side wall portion for storing the substrate, The outer periphery of the main portion of the substrate is surrounded by the side wall portion, At least a portion of an outer periphery of the protruding portion of the substrate is not surrounded by the side wall portion.

8. A fan, characterized in that: have: A motor unit according to claim 6 or 7, and The impeller is configured to be rotatable by the rotational force of the motor.

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