JP2016131191A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device which can ensure radiation performance and improve noise removal performance to a further degree.SOLUTION: A wiring board 12 comprises: lands 121, 122 to which a choke coil 111 is electrically connected; and a heat conduction pattern 125 which is provided between the lands 121, 122 and grounded to a ground GND. Capacitors 126, 127 are formed by the lands 121, 122 and the heat conduction pattern 125. Since the heat conduction pattern 125 is grounded to the ground GND, a π-type filter circuit 14 is composed of the choke coil 111 and the capacitors 126, 127. Shapes of the lands 121, 122 and the heat conduction pattern 125 are set to make length of edges opposite to each other be longer compared to a case where the edges opposite to each other are straight lines. As a result, capacitance of each of the capacitors 126, 127 can be increased. Accordingly, the π-type filter circuit 14 can be successfully operated.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an electronic device including a wiring board provided with a heat conduction pattern between connecting portions.

  Conventionally, as an electronic device provided with a wiring board in which a heat conduction pattern is provided between connecting portions, for example, there is an electronic device disclosed in Patent Document 1 shown below.

  This electronic device includes a component and a flexible substrate. The component includes a plurality of terminal portions protruding from the left and right side surfaces of the main body portion. The flexible substrate includes a first land to which the terminal portion of the component is electrically connected and a second land to which the terminal portion is not electrically connected. The first lands are provided at a predetermined interval according to the terminal portion. On the other hand, the second land is provided between the first lands. When the terminal portion of the component is electrically connected to the first land via the solder, the second land is disposed below the main body portion of the component. Therefore, the heat generated in the main body can be radiated to the outside through the second land. Here, the flexible substrate corresponds to the wiring substrate, the first land corresponds to the connection portion, and the second land corresponds to the heat conduction pattern.

JP 2001-210984 A

  By the way, in the electronic device described above, when the second land is grounded to the ground, the area of the ground pattern on the flexible substrate can be increased. As a result, the ground impedance can be kept low, and noise can be reduced. However, it is difficult to sufficiently reduce noise by itself.

  The present invention has been made in view of such circumstances, and in an electronic device including a wiring board in which a heat conduction pattern is provided between connection portions, while ensuring heat dissipation performance, further improving noise removal performance. An object of the present invention is to provide an electronic device that can be made to operate.

  The present invention made to solve the above problems includes a main body, a coil having a plurality of terminal portions provided on the main body, a plurality of connection portions to which the terminal portions are electrically connected, and a connection portion. And a wiring board having a heat conduction pattern electrically connected to the ground, the connection portion and the heat conduction pattern are compared with a case where the opposing sides are in a straight line with each other. The shape is set so that the lengths of the opposing sides become longer.

  According to this configuration, the heat generated in the coil can be dissipated through the heat conduction pattern as in the conventional case. Further, according to this configuration, the capacitor is formed by the connection portion and the heat conduction pattern. Since the heat conduction pattern is electrically connected to the ground, a π-type filter circuit is configured by the coil electrically connected to the connection portion and the capacitor formed by the connection portion and the heat conduction pattern. The shape of the connecting portion and the heat conduction pattern is set so that the length of the opposing sides is longer than when the opposing sides are in a straight line. Therefore, the capacitance of the capacitor formed by the connection portion and the heat conduction pattern can be increased as compared with the general case where the opposing sides are provided so as to be in a straight line. Therefore, the π-type filter circuit can function reliably. Thereby, while ensuring heat dissipation performance, noise removal performance can be improved more.

It is a circuit diagram of the motor drive device in a 1st embodiment. It is a top view of the choke coil in FIG. It is the III-III arrow sectional drawing in FIG. It is a left view of the choke coil in FIG. It is a right view of the choke coil in FIG. It is a bottom view of the choke coil in FIG. It is a top view of the wiring board in which a choke coil is mounted. It is VIII-VIII arrow sectional drawing in FIG. It is a top view of a wiring board in the state where a choke coil was mounted. It is XX arrow sectional drawing in FIG. It is an equivalent circuit diagram of a wiring board in a state where a choke coil is mounted. It is a top view of the wiring board in the modification of a 1st embodiment. It is a top view of the choke coil in 2nd Embodiment. It is XIV-XIV arrow sectional drawing in FIG. It is a bottom view of the choke coil in 2nd Embodiment. It is a top view of a wiring board in the state where a choke coil was mounted. It is XVII-XVII arrow sectional drawing in FIG.

  Next, the present invention will be described in more detail with reference to embodiments. In the present embodiment, an example applied to a motor drive device mounted on a vehicle and driving a motor is shown.

(First embodiment)
First, the configuration of the motor drive device of the first embodiment will be described with reference to FIGS.

  A motor driving device 1 (electronic device) shown in FIG. 1 is a device that is mounted on a vehicle and drives a motor M for assisting steering of a steering wheel. The motor drive device 1 includes an inverter circuit 10 and a filter circuit 11.

The inverter circuit 10 is a circuit that has a switching element, drives the motor M by converting the direct current supplied from the battery B into alternating current by supplying the switching element, and supplying the alternating current to the motor M. The positive input terminal and the negative input terminal of the inverter circuit 10 are electrically connected to the positive terminal and the negative terminal of the battery B through the filter circuit 11, respectively.
The output end is electrically connected to the motor M.

  The filter circuit 11 suppresses noise transmitted from the other device (not shown) electrically connected to the battery B to the inverter circuit 10 and is transmitted from the inverter circuit 10 to another device electrically connected to the battery B. This circuit suppresses noise. The filter circuit 11 includes a capacitor 110 and a choke coil 111 (coil).

  The capacitor 110 and the choke coil 111 are elements for configuring the filter circuit 11. One end of the capacitor 110 is electrically connected to the positive terminal of the battery B, and the other end is electrically connected to the negative terminal of the battery B and the negative input terminal of the inverter circuit 10. The negative terminal of the battery B is grounded to the ground GND. Specifically, it is electrically connected to a vehicle body that is a reference potential point. One end of the choke coil 111 is electrically connected to one end of the capacitor 110, and the other end is electrically connected to the positive input terminal of the inverter circuit 10.

  As shown in FIGS. 2 to 6, the choke coil 111 is a surface-mount type element and includes a main body portion 111 a and terminal portions 111 b and 111 c.

  The main body 111a is a rectangular parallelepiped portion made of resin in which the choke coil element 111d is embedded. The terminal portions 111b and 111c are portions that form terminals of the choke coil element 111d. The terminal portions 111b and 111c are made of a bent plate-shaped member made of metal. The terminal portion 111b is electrically connected to one end of the choke coil element 111d, and is provided in the lower left corner of the main body portion 111a with the side surface and the lower surface exposed. The terminal portion 111c is electrically connected to the other end of the choke coil element 111d, and is provided with the side surface and the lower surface exposed at the lower right corner of the main body portion 111a.

  The choke coil 111 is mounted on the wiring board 12 and is electrically connected to the capacitor 110 and the inverter circuit 10.

  The wiring board 12 shown in FIGS. 7 and 8 is a member for wiring the choke coil 111. The wiring substrate 12 includes a substrate 120, lands 121 and 122 (connection portions), wiring patterns 123 and 124, and a heat conduction pattern 125.

  The substrate 120 is a plate-like member made of an insulating resin.

  The lands 121 and 122 are thin plate members made of metal to which the terminal portions 111b and 111c of the choke coil 111 are electrically connected. The lands 121 and 122 are provided on the surface of the substrate 120 with a predetermined interval corresponding to the terminal portions 111b and 111c.

  The wiring patterns 123 and 124 are thin plate-like members made of metal for wiring the terminal portions 111 b and 111 c through the lands 121 and 122. It is also a member that conducts heat generated in the main body 111a and dissipates it to the outside. The wiring patterns 123 and 124 are provided integrally with the lands 121 and 122 on the surface of the substrate 120, respectively.

  The heat conduction pattern 125 is a thin plate-like member made of metal for conducting heat generated in the main body 111a and dissipating it to the outside. The heat conduction pattern 125 is provided between the lands 121 and 122 on the surface of the substrate 120 with a certain distance from the lands 121 and 122.

  As illustrated in FIG. 7, the lands 121 and 122 and the heat conduction pattern 125 are configured so that the lengths of the opposing sides are longer than when the opposing sides are straight. Specifically, the opposing sides are set to face each other in a state where they are bent in a sawtooth shape with a certain interval. Therefore, the capacitors 126 and 127 having larger capacities are formed by the land 121 and the heat conduction pattern 125 and the land 122 and the heat conduction pattern 125 as compared with the case where the opposing sides are in a straight line.

  As shown in FIG. 9, the choke coil 111 is arranged in the center portion of the wiring board 12 with the terminal portion 111 b exposed on the lower surface of the main body portion 111 a facing the land 121 and the terminal portion 111 c facing the land 122. Yes. As shown in FIG. 10, the terminal portion 111 b is electrically connected to the land 121, and the terminal portion 111 c is electrically connected to the land 122 via the solder 13.

  The heat conduction pattern 125 is grounded to the ground GND shown in FIG. Therefore, as shown in FIG. 11, the π-type filter circuit 14 including the choke coil 111 and the capacitors 126 and 127 is configured. That is, in addition to the filter circuit 11 shown in FIG. 1, the π-type filter circuit 14 shown in FIG. 11 is configured.

  Next, the operation of the motor drive apparatus according to the first embodiment will be described with reference to FIGS. 1, 2, and 9 to 11.

  The inverter circuit 10 shown in FIG. 1 converts the direct current supplied from the battery B into an alternating current by switching the switching element, supplies the alternating current to the motor M, and drives the motor M. As a result, the motor M generates torque and assists the steering wheel. At that time, the filter circuit 11 suppresses noise transmitted from the other device electrically connected to the battery B to the inverter circuit 10 and also transmits noise transmitted from the inverter circuit 10 to the other device electrically connected to the battery B. Suppress. Similarly, the π-type filter circuit 14 shown in FIG. 11 is also connected to the battery B from the inverter circuit 10 while suppressing noise transmitted to the inverter circuit 10 from other devices electrically connected to the battery B. Suppresses noise transmitted to other devices.

  In FIG. 1, when a direct current is supplied from the battery B to the inverter circuit 10, a current flows through the choke coil 111. When the auxiliary torque is large, a larger current flows. When a large current flows through the choke coil 111, the choke coil element 111d shown in FIG. 2 generates heat. The heat generated in the choke coil element 111d is radiated to the outside through the terminal portion 111b, the solder 13 land 121, and the wiring pattern 123 shown in FIGS. Further, heat is radiated to the outside through the terminal portion 111 c, the solder 13, the land 122, and the wiring pattern 124. Further, heat is radiated from the main body 111a to the outside through the heat conduction pattern 125. As a result, the temperature rise of the choke coil 111 is suppressed.

  Next, the effect of the motor drive device of the first embodiment will be described.

  According to the first embodiment, the motor driving device 1 includes the choke coil 111 and the wiring board 12. The choke coil 111 includes a main body portion 111a and terminal portions 111b and 111c provided on the main body portion 111a. The wiring board 12 includes lands 121 and 122 to which the terminal portions 111b and 111c are electrically connected, respectively, and a heat conductive pattern 125 provided between the lands 121 and 122 and grounded to the ground GND. Therefore, capacitors 126 and 127 are formed by the lands 121 and 122 and the heat conduction pattern 125. Since the heat conduction pattern 125 is grounded to the ground GND, the choke coil 111 and the capacitors 126 and 127 constitute the π-type filter circuit 14. The lands 121 and 122 and the heat conduction pattern 125 are shaped so that the lengths of the opposing sides are longer than when the opposing sides are straight. Therefore, the capacitances of the capacitors 126 and 127 can be increased as compared with the general case where the opposing sides are provided in a straight line. Therefore, the π-type filter circuit 14 can function reliably. Thereby, while ensuring heat dissipation performance, noise removal performance can be improved more.

  According to the first embodiment, the lands 121 and 122 and the heat conduction pattern 125 are set so that the opposing sides face each other in a bent state. Specifically, the shape is set so that the opposing sides face each other while being bent in a sawtooth shape. Therefore, the length of the opposing sides can be reliably increased as compared with the case where the opposing sides are in a straight line. Therefore, the capacitances of the capacitors 126 and 127 can be reliably increased.

  In the first embodiment, the choke coil 111 includes one choke coil element 111d and two terminal portions 111b and 111c. However, the present invention is not limited to this. The choke coil 111 may include two or more choke coil elements. Moreover, you may provide the 3 or more terminal part.

  In the first embodiment, the lands 121 and 122 and the heat conduction pattern 125 are set so as to face each other with their opposite sides bent in a sawtooth shape. However, the present invention is not limited to this. Absent. As shown in FIG. 12, the opposing sides may be set to face each other in a state of being bent in a wave shape. Further, the opposing sides may be set to face each other in a state where they are bent in a sine wave shape. Further, the opposing sides may be set to face each other in a state where they are bent in a comb-teeth shape. As long as the shape is set so that the length of the opposing sides is longer than that in the case where the opposing sides are in a straight line, any shape may be used.

  In the first embodiment, the choke coil 111 is an example of a surface-mount type element, but is not limited thereto. It may be an insertion mounting type element.

(Second Embodiment)
Next, the motor drive device of 2nd Embodiment is demonstrated. The motor drive device according to the second embodiment is a device in which a heat conduction portion is provided in the choke coil with respect to the motor drive device according to the first embodiment so that heat conduction from the choke coil to the heat conduction pattern of the wiring board is facilitated. Since the configuration other than the heat conduction unit and the operation other than the heat radiation are the same as those in the first embodiment, the description is omitted except when necessary. First, the configuration of the choke coil and the connection relationship with the wiring board in the motor drive device of the second embodiment will be described with reference to FIGS.

  As shown in FIGS. 13 to 15, the choke coil 211 is a surface-mount type element, and includes a main body portion 211a, terminal portions 211b and 211c, and a heat conducting portion 211e. The main body portion 211a and the terminal portions 211b and 211c have the same configuration as the main body portion 111a and the terminal portions 111b and 111c of the first embodiment.

  The heat conducting part 211e is a part for conducting heat generated in the choke coil element 211d. The heat conducting portion 211e is configured by a rectangular plate member made of metal. The heat conducting portion 211e is not electrically connected to the choke coil element 211d, and is provided on the lower surface of the main body portion 211a with the lower surface exposed between the terminal portions 211b and 211c.

  As shown in FIGS. 16 and 17, the wiring substrate 22 includes a substrate 220, lands 221 and 222 (connection portions), wiring patterns 223 and 224, and a heat conduction pattern 225. The substrate 220, the lands 221 and 222, the wiring patterns 223 and 224, and the heat conduction pattern 225 have the same configuration as the substrate 120, the lands 121 and 122, the wiring patterns 123 and 124, and the heat conduction pattern 125 of the first embodiment.

  As shown in FIG. 16, in the choke coil 211, the terminal portion 211b exposed on the lower surface of the main body portion 211a faces the land 221, the terminal portion 211c faces the land 222, and the heat conduction portion 211e faces the heat conduction pattern 225. In the central portion of the wiring board 22. As shown in FIG. 17, the terminal portion 211 b is electrically connected to the land 221, and the terminal portion 211 c is electrically connected to the land 222 via solder 23. Further, the heat conducting portion 211e is thermally connected to the heat conducting pattern 225 via the solder 23.

  Next, heat dissipation of the choke coil in the motor drive device of the second embodiment will be described with reference to FIGS. 13, 16 and 17.

  The heat generated in the choke coil element 211d shown in FIG. 13 is radiated to the outside through the terminal portion 211b, the solder 23, the land 221 and the wiring pattern 223 shown in FIGS. Further, heat is radiated to the outside through the terminal portion 211c, the solder 23, the land 222, and the wiring pattern 224. Further, heat is radiated from the main body portion 211a to the outside through the heat conducting portion 211e, the solder 23, and the heat conducting pattern 125.

  Next, the effect of the motor drive device of 2nd Embodiment is demonstrated.

  According to the second embodiment, by having the same configuration as that of the first embodiment, the same effect as that of the first embodiment corresponding to the same configuration can be obtained.

  According to the second embodiment, the choke coil 211 is a main body portion 211a and includes a heat conducting portion 211e between the terminal portions 211b and 211c. Therefore, the heat generated in the choke coil element 211d can be conducted to the heat conduction pattern 225 via the heat conduction portion 211e. Therefore, the heat dissipation performance can be improved compared to the first embodiment.

  According to the second embodiment, the heat conducting part 211 e is thermally connected to the heat conducting pattern 225 via the solder 23. Therefore, the heat generated in the choke coil element 211 d can be reliably conducted to the heat conduction pattern 225 through the solder 23. Therefore, the heat dissipation performance can be reliably improved as compared with the first embodiment.

  In the second embodiment, the choke coil 211 includes one choke coil element 211d and two terminal portions 211b and 211c. However, the present invention is not limited to this. The choke coil 211 may include two or more choke coil elements. Moreover, you may provide the 3 or more terminal part.

  In the second embodiment, the heat conductive portion 211e is thermally connected to the heat conductive pattern 225 via the solder 23. However, the present invention is not limited to this. It may be thermally connected via a gel-like heat conducting member.

  DESCRIPTION OF SYMBOLS 1 ... Motor drive device (switch apparatus), 111 ... Choke coil (coil), 111a ... Main-body part, 111b, 111c ... Terminal part, 111d ... Choke coil element, 12 ... Wiring board, 120... Board, 121, 122... Land (connection part), 123, 124... Wiring pattern, 125... Heat conduction pattern, 126, 127. Solder, 14 ... π-type filter circuit

Claims (5)

A coil (111, 211) having a main body portion (111a, 211a) and a plurality of terminal portions (111b, 111c, 211b, 211c) provided on the main body portion;
A plurality of connection portions (121, 122, 221, 222) to which the terminal portions are electrically connected, and a heat conduction pattern (125, 225) provided between the connection portions and electrically connected to the ground. And a wiring board (12, 22) having
In an electronic device comprising:
The electronic device is characterized in that the connecting portion and the heat conduction pattern are shaped so that the length of the opposing sides is longer than that in the case where the opposing sides are straight.   2. The electronic device according to claim 1, wherein the connection portion and the heat conduction pattern are configured to face each other in a state where opposing sides are bent.   3. The electronic device according to claim 2, wherein the connection part and the heat conduction pattern are configured to face each other with opposing sides bent in a sawtooth shape.   The electronic device according to any one of claims 1 to 3, wherein the coil (211) is a main body portion and includes a heat conducting portion (211e) between the terminal portions.   The electronic device according to claim 4, wherein the heat conducting unit is thermally connected to the heat conducting pattern.

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