Surge suppression device

Abstract

To provide a surge suppression device which hardly transmits heat to a capacitor.SOLUTION: A surge suppression device 1 includes: a Zener diode 312; capacitors 322 connected in parallel with the Zener diode 312; one or more resistances 311 and 321 connected in series with the Zener diode 312 and the capacitors 322, in a closed circuit part 3 including the Zener diode 312 and the capacitors 322; a substrate 4 on which the Zener diode 312, the capacitor 322 and the one or more resistances 311 and 321 are mounted; and a heat sink 6 mounted on the substrate 4. The heat sink 6 is arranged on a side opposite to heat dissipation object resistances 311 and 321 which are at least the one resistance 311 and 321 across the substrate 4, and is arranged at a position which overlaps at least a part of the heat dissipation object resistances 311 and 321 and does not overlap the capacitor 322, in a thickness direction X of the substrate 4.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a surge suppression device.

Background Art

[0002] Patent Document 1 discloses a surge suppression device that is connected to the wiring between an inverter and a motor and suppresses the surge voltage generated due to the switching operation of the inverter. The surge suppression unit described in Patent Document 1 has three series circuit portions of a resistor and a capacitor. In the three series circuit portions, the resistor-side end portions are connected to the wiring of each phase, and the capacitor-side end portions are connected to each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a surge suppression device, if not particularly devised, a specific resistor generates heat during use, and this heat may be transmitted to the capacitor and have an adverse effect on the capacitor.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a surge suppression device in which heat is difficult to be transmitted to the capacitor.

Means for Solving the Problems

[0006] To achieve the above objective, the present invention provides a surge suppression device comprising: a Zener diode; a capacitor connected in parallel with the Zener diode; one or more resistors connected in series with the Zener diode and the capacitor in a closed circuit section including the Zener diode and the capacitor; a substrate on which the Zener diode, the capacitor and the one or more resistors are mounted; and a heat sink attached to the substrate, wherein the heat sink is positioned on the opposite side of the substrate from at least one of the resistors to be heated, and in the thickness direction of the substrate, it is positioned to overlap with at least a portion of the resistors to be heated but not with the capacitor. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a surge suppression device that makes it difficult for heat to be transferred to the capacitor. [Brief explanation of the drawing]

[0008] [Figure 1] This is a circuit diagram showing an example of the usage state of the surge suppression device in the first embodiment. [Figure 2] This is a front view of the surge suppression device in the first embodiment. [Figure 3] This is a rear view of the surge suppression device in the first embodiment. [Figure 4] This is a side view of the surge suppression device in the first embodiment. [Figure 5] This is a perspective view of the surge suppression device in the first embodiment. [Figure 6] This is a cross-sectional view taken along the line VI-VI in Figure 3. [Figure 7] This is a rear view of the surge suppression device in the second embodiment. [Figure 8] This is an enlarged cross-sectional view of a part of the surge suppression device in the second embodiment. [Modes for carrying out the invention]

[0009] [First Embodiment] A first embodiment of the present invention will be described with reference to Figures 1 to 6. The embodiments described below are presented as preferred specific examples for carrying out the present invention, and while some parts specifically illustrate various technically preferable technical matters, the technical scope of the present invention is not limited to these specific embodiments.

[0010] This embodiment relates to a surge suppression device 1. First, the circuit configuration of the surge suppression device 1 will be described, followed by a description of the structure of the surge suppression device 1.

[0011] Figure 1 is a circuit diagram showing an example of the operation state of the surge suppression device 1 of this embodiment. The surge suppression device 1 is used by connecting it to, for example, the U-phase wiring 93u, V-phase wiring 93v, and W-phase wiring 93w between the motor 91 and the inverter 92. In this case, the surge suppression device 1 suppresses the application of surge voltage to the motor 91.

[0012] The surge suppression device 1 includes a U-phase upper diode 21u, a V-phase upper diode 21v, a W-phase upper diode 21w, a U-phase lower diode 22u, a V-phase lower diode 22v, a W-phase lower diode 22w, a first resistor 311, a Zener diode 312, a second resistor 321, a capacitor 322, and a balance resistor 323.

[0013] The anode of the U-phase upper diode 21u is connected to the U-phase wiring 93u, the anode of the V-phase upper diode 21v is connected to the V-phase wiring 93v, and the anode of the W-phase upper diode 21w is connected to the W-phase wiring 93w. The cathodes of the U-phase upper diode 21u, V-phase upper diode 21v, and W-phase upper diode 21w are connected to a common upper wire section 11. In this embodiment, an example is shown in which two U-phase upper diodes 21u are connected in series, two V-phase upper diodes 21v are connected in series, and two W-phase upper diodes 21w are connected in series, but the number of these can be changed as appropriate.

[0014] The cathode of the U-phase lower diode 22u is connected to the U-phase wiring 93u, the cathode of the V-phase lower diode 22v is connected to the V-phase wiring 93v, and the cathode of the W-phase lower diode 22w is connected to the W-phase wiring 93w. The anodes of the U-phase lower diode 22u, V-phase lower diode 22v, and W-phase lower diode 22w are connected to a common lower wire section 12. In this embodiment, an example is shown in which two U-phase lower diodes 22u are connected in series, two V-phase lower diodes 22v are connected in series, and two W-phase lower diodes 22w are connected in series, but the number of these can be changed as appropriate.

[0015] Between the upper line section 11 and the lower line section 12, a first series circuit section 31, in which a first resistor 311 and a Zener diode 312 are connected in series, and a second series circuit section 32, in which a second resistor 321 and a capacitor 322 are connected in series, are connected in parallel.

[0016] The first series circuit section 31 has one first resistor 311 and four Zener diodes 312 connected in series. The first resistor 311 suppresses inrush current to the U-phase upper diode 21u, the V-phase upper diode 21v, the W-phase upper diode 21w, the U-phase lower diode 22u, the V-phase lower diode 22v, the W-phase lower diode 22w, and the four Zener diodes 312. The breakdown voltage (Zener voltage) of the four Zener diodes 312 is designed so that the capacitor 322 maintains a voltage equivalent to, for example, a predetermined pulse voltage value output from the inverter 92. As a result, current flows through the closed circuit section 3 (i.e., the closed circuit including the Zener diodes 312 and the capacitor 322), which consists of the first series circuit section 31 and the second series circuit section 32, when a voltage exceeding the predetermined pulse voltage value output from the inverter 92 occurs in the U-phase wiring 93u, V-phase wiring 93v, or W-phase wiring 93w. The number of Zener diodes 312 can be changed as appropriate according to the breakdown voltage (Zener voltage) of the Zener diodes 312. The cathode side of each Zener diode 312 is connected to the first resistor 311 side. In the first series circuit section 31, the first resistor 311 side is connected to the upper line section 11, and the Zener diode 312 side is connected to the lower line section 12.

[0017] The second series circuit section 32 includes one second resistor 321, eight capacitors 322 connected in series-parallel, and four balance resistors 323 connected in parallel with the capacitors 322. The second resistor 321 suppresses the inrush current to the U-phase upper diode 21u, V-phase upper diode 21v, W-phase upper diode 21w, U-phase lower diode 22u, V-phase lower diode 22v, W-phase lower diode 22w, and the capacitors 322. The eight capacitors 322 are formed by connecting four sets of two capacitors 322 connected in parallel in series. The capacitors 322 store electric charges due to the surge voltage generated in the U-phase wiring 93u, V-phase wiring 93v, and W-phase wiring 93w. The balance resistors 323 suppress the voltage imbalance generated by connecting a plurality of capacitors 322 in series. The number of these capacitors 322 and balance resistors 323 can be changed as appropriate. Also, for example, when a plurality of capacitors 322 are not connected in series, the balance resistors 323 can be omitted. The second series circuit section 32 is connected such that the second resistor 321 side is connected to the upper line portion 11, and the capacitor 322 side is connected to the lower line portion 12.

[0018] As described above, the circuit configuration of the surge suppression device 1 according to this embodiment has been described, but various modifications are possible as long as surge suppression is possible. As an example, a configuration in which the second resistor 321 is arranged on at least one of the upper line portion 11 and the lower line portion 12 can be considered.

[0019] Next, while referring to FIGS. 2 to 6, the structure of the surge suppression device 1 according to this embodiment will be described. FIG. 2 is a front view of the surge suppression device 1. FIG. 3 is a rear view of the surge suppression device 1. FIG. 4 is a side view of the surge suppression device 1. FIG. 5 is a perspective view of the surge suppression device 1. FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 3.

[0020] As shown in Figures 2 and 3, the surge suppression device 1 comprises a substrate 4, three terminal fittings 5 ​​fixed to the substrate 4, various mounted components mounted on the substrate 4, a heat sink 6 attached to the substrate 4, and a heat transfer sheet 7 interposed between the substrate 4 and the heat sink 6. The various mounted components mounted on the substrate 4 include two U-phase upper diodes 21u, two V-phase upper diodes 21v, two W-phase upper diodes 21w, two U-phase lower diodes 22u, two V-phase lower diodes 22v, two W-phase lower diodes 22w, one first resistor 311, four Zener diodes 312, one second resistor 321, eight capacitors 322, and four balance resistors 323.

[0021] The substrate 4 is formed in the shape of a rectangular plate. The substrate 4 has a base material 41 made of an electrically insulating resin or the like, and conductive patterns 42 made of copper foil or the like formed on both sides of the base material 41, and a plurality of through holes 43 are formed that penetrate the base material 41. Hereafter, the thickness direction of the substrate 4 will be referred to as the substrate thickness direction X.

[0022] The three terminal fittings 5 ​​are electrically connected to different wirings: U-phase wiring (see reference numeral 93u in Figure 1), V-phase wiring (see reference numeral 93v in Figure 1), and W-phase wiring (see reference numeral 93w in Figure 1). The three terminal fittings 5 ​​are also electrically connected to the conductive pattern 42 on the substrate 4. The three terminal fittings 5 ​​are mounted side-by-side at one end of the substrate 4. Hereafter, the direction in which the three terminal fittings 5 ​​are aligned will be referred to as the transverse direction Y, and the direction perpendicular to both the substrate thickness direction X and the transverse direction Y will be referred to as the longitudinal direction Z. In this embodiment, the longitudinal direction Z is the longitudinal direction of the substrate 4, and the transverse direction Y is the short-side direction of the substrate 4.

[0023] As shown in Figures 2 to 5, the terminal fitting 5 comprises a first terminal portion 51, a second terminal portion 52, and a third terminal portion 53. The first terminal portion 51 is formed in a plate shape perpendicular to the substrate thickness direction X and is fastened together with the substrate 4 using a bolt B and a nut N. The second terminal portion 52 protrudes from the first terminal portion 51 in the vertical direction Z and is inserted into a through hole 44 formed in the substrate 4. The second terminal portion 52 is formed to be narrower in the lateral direction Y than the first terminal portion 51. The third terminal portion 53 extends in the substrate thickness direction X from the end of the first terminal portion 51 opposite to the second terminal portion 52. For example, the terminal fitting 5 can be formed by punching out a metal plate into a predetermined shape and bending the portions that will become the second terminal portion 52 and the third terminal portion 53 to one side in the substrate thickness direction X. The second terminal portion 52 and the third terminal portion 53 are bent from the first terminal portion 51 toward the side where the substrate 4 is located relative to the first terminal portion 51.

[0024] The third terminal section 53 has a bolt insertion hole 531 through which a bolt (not shown) is inserted to fix the terminal fitting 5 to the connection point. Terminals connected to U-phase wiring (see reference numeral 93u in Figure 1), V-phase wiring (see reference numeral 93v in Figure 1), or W-phase wiring (see reference numeral 93w in Figure 1) are connected to the third terminal section 53 of the terminal fitting 5. The terminal fitting 5 is mounted on a terminal block, for example, provided on the motor case. Therefore, when the surge suppression device 1 is in use, heat dissipation from the three terminal fittings 5 ​​is promoted to the motor case, etc., and the surge suppression device 1 becomes relatively cool.

[0025] As shown in Figure 2, the various components mounted on board 4 include two U-phase upper diodes 21u, two V-phase upper diodes 21v, two W-phase upper diodes 21w, two U-phase lower diodes 22u, two V-phase lower diodes 22v, two W-phase lower diodes 22w, a first resistor 311, a second resistor 321, eight capacitors 322, and four balance resistors 323, all mounted on one side of board 4, and four Zener diodes 312, all mounted on the other side of board 4, as shown in Figure 3.

[0026] As shown in Figure 2, the two U-phase upper diodes 21u, two V-phase upper diodes 21v, two W-phase upper diodes 21w, two U-phase lower diodes 22u, two V-phase lower diodes 22v, two W-phase lower diodes 22w, eight capacitors 322, and four balance resistors 323 are all chip type. The first resistor 311 and the second resistor 321 are resistors of the type that have lead wires 311a and 321a, respectively. In other words, in this embodiment, of the components mounted on the board 4, only the first resistor 311 and the second resistor 321 are leaded components that have lead wires.

[0027] In the closed circuit section (see reference numeral 3 in Figure 1) including the Zener diode 312 and the capacitor 322, one or more of the resistors connected to the Zener diode 312 and the capacitor 322 (i.e., the first resistor 311 and the second resistor 321) are the resistors to be heated. Furthermore, the resistors to be heated are the resistors that are to be heated by the heat sink 6, and at least a portion of them are resistors that overlap with the heat sink 6 in the substrate thickness direction X, with the substrate 4 in between. As shown in Figure 2, in this embodiment, the resistors to be heated are both the first resistor 311 and the second resistor 321. However, this is not limited to this, and if there are multiple resistors connected to the Zener diode 312 and the capacitor 322 in the closed circuit section 3, at least one of them may be designated as the resistor to be heated. In Figure 2, the outer shape of the heat sink 6 is shown by a dashed line.

[0028] The heat sink 6 is made of a material with high thermal conductivity. As shown in Figures 3 and 5, the heat sink 6 has a rectangular flat plate portion 61 with thickness in the substrate thickness direction X, and a plurality of plate-shaped fin portions 62 that protrude from the flat plate portion 61 on the side opposite to the substrate 4. Each of the plurality of fin portions 62 extends in the vertical direction Z and is formed at predetermined intervals in the horizontal direction Y.

[0029] In this embodiment, the surge suppression device 1 is assumed to be used in a configuration where the vertical direction Z is vertical and the side of the substrate 4 to which the three terminal fittings 5 ​​are attached is the upper side in the vertical direction. In such a case, as described above, by setting the formation direction of the fin portion 62 to the vertical direction Z (i.e., the vertical direction), heat in the space between adjacent fin portions 62 can easily escape to the upper side in the vertical direction.

[0030] The shape of the heatsink 6 is not limited to those described above. For example, the fin portion 62 may extend in a direction intersecting the vertical direction Z, and may also have a shape other than a plate (e.g., columnar).

[0031] As shown in Figure 2, the heat sink 6 is mounted on the substrate 4 opposite the first resistor 311 and the second resistor 321 (i.e., the resistors to be heated). In this embodiment, the entire first resistor 311 is positioned so that it overlaps with the heat sink 6 in the substrate thickness direction X, and a portion of the second resistor 321 is positioned so that it overlaps with the heat sink 6 in the substrate thickness direction X. In addition, in this embodiment, the first resistor 311 and the second resistor 321, which are mounted components with leads among the mounted components on the substrate 4, are positioned on the opposite side of the substrate 4 from the heat sink 6.

[0032] The heatsink 6 is positioned so as not to overlap with the eight capacitors 322 in the substrate thickness direction X. The heatsink 6 is positioned on the opposite side of the substrate 4 from the side with the eight capacitors 322 in the substrate thickness direction X. The capacitors 322 may be positioned on the side of the substrate 4 where the heatsink 6 is located.

[0033] At least one of the eight capacitors 322 is located in a region different from the region where the heat sink 6 is located in the lateral direction Y. In this embodiment, of the eight capacitors 322 shown in Figure 2, six capacitors 322, excluding the two leftmost capacitors 322, are located in a region different from the region where the heat sink 6 is located in the lateral direction Y. This suppresses the transfer of heat from the heat sink 6 to the capacitors 322. From this viewpoint, it is preferable that all capacitors 322 are located in a region different from the region where the heat sink 6 is located in the lateral direction Y. However, in this case, the substrate 4 may tend to become larger in the lateral direction Y. Therefore, from the viewpoint of suppressing both heat transfer from the heat sink 6 to the capacitors 322 and suppressing the enlargement of the substrate 4, it is preferable that only some of the capacitors 322 are located in a region different from the region where the heat sink 6 is located in the lateral direction Y. Note that all capacitors 322 may be formed in the region where the heat sink 6 is located in the lateral direction Y.

[0034] The eight capacitors 322 are located in a region different from the region where the heatsink 6 is located in the vertical direction Z. That is, in Figure 2, the eight capacitors 322 are located in a position shifted below the heatsink 6. In the vertical direction Z, the three terminals, the heatsink 6, the first resistor 311 and the second resistor 321, and the capacitors 322 are arranged in this order.

[0035] The positional relationship between the heatsink 6 and the four balance resistors 323 is the same as the positional relationship between the heatsink 6 and the eight capacitors 322. In the vertical Z direction, the eight capacitors 322 are located on the side of the balance resistors 323 that is opposite the heatsink 6. As a result, the capacitors 322 are further away from the heatsink 6, making it more difficult for heat from the heatsink 6 to be transferred to the capacitors 322.

[0036] As shown in Figure 3, on the side of the substrate 4 to which the heat sink 6 is attached, there are no mounted components on either side of the heat sink 6 in the vertical direction Z. This suppresses the effect of heat dissipated from the heat sink 6 along the vertical direction Z, which is the direction in which the fin portion 62 is formed, on mounted components.

[0037] As shown in Figures 4 and 5, the third terminal portion 53 of the terminal fitting 5 is formed on the side opposite the heat sink 6 in the substrate thickness direction X, away from the first terminal portion 51, and the heat sink 6 and the third terminal portion 53 are formed in positions that do not overlap in the vertical direction Z. As a result, when the surge suppression device 1 is positioned with the vertical direction Z being vertical, the heat dissipated from the heat sink 6 along the fin portion 62 in the vertical direction Z is blocked by the terminal fitting 5, which prevents hot air from accumulating near the surge suppression device 1.

[0038] As shown in Figures 5 and 6, the heatsink 6 is thermally connected to the terminal fittings 5. In this embodiment, the end of the heatsink 6 on the terminal fitting 5 side in the vertical direction Z is in direct contact with two of the three terminal fittings 5. The heatsink 6 is in contact with the surface of the second terminal portion 52 of the terminal fitting 5. In this embodiment, the heatsink 6 is positioned so as not to overlap with the first terminal portion 51 of the terminal fitting 5.

[0039] To prevent electrical conductivity between the terminal fittings 5 ​​via the heat sink 6, the heat sink 6 is made of an insulator such as an electrically insulating resin. However, if electrical insulation between the heat sink 6 and the terminal fittings 5 ​​is ensured, for example by interposing an insulating sheet between the heat sink 6 and the terminal fittings 5, the heat sink 6 can also be made of a conductor such as metal. In this case, as described above, it is preferable that the insulating sheet be thin enough to allow heat transfer, or that a material with high thermal conductivity be selected, in order to thermally connect the heat sink 6 and the terminal fittings 5. As described above, the terminal fittings 5 ​​are relatively cold compared to other parts of the surge suppression device 1 when it is in use, and the heat sink 6 is thermally connected to the terminal fittings 5, thereby improving the heat dissipation of the heat sink 6.

[0040] Here, the state in which the heatsink 6 is thermally connected to the terminal fitting 5 means that heat is directly transferred between the heatsink 6 and the terminal fitting 5, or that the heat transfer efficiency is sufficiently high. For example, if the heatsink 6 and the terminal fitting 5 are in direct contact, or if they are in contact via a material with high thermal conductivity, the heatsink 6 can be said to be thermally connected to the terminal fitting 5. Furthermore, even if the heatsink 6 and the terminal fitting 5 are in contact via a material with low thermal conductivity, if the thickness of the material is small and sufficient heat exchange and transfer occurs between the heatsink 6 and the terminal fitting 5, the heatsink 6 can be said to be thermally connected to the terminal fitting 5. The same applies when other components are thermally connected to each other.

[0041] As shown in Figure 3, the side of the heat sink 6 facing the substrate 4 faces the heat dissipation opposing patterns 421 and 422 formed on the heat sink 6 side of the substrate 4. The heat dissipation opposing patterns 421 and 422 are part of the conductive pattern 42 formed on the substrate 4, and are wider than other parts of the conductive pattern 42. The heat dissipation opposing patterns 421 and 422 face the heat sink 6 via a heat transfer sheet 7. In this embodiment, the heat dissipation opposing patterns 421 and 422 are formed in a position that does not overlap with the eight capacitors 322 in the substrate thickness direction X.

[0042] In this embodiment, the heat dissipation opposing patterns 421 and 422 consist of two heat dissipation opposing patterns: a first heat dissipation opposing pattern 421 and a second heat dissipation opposing pattern 422. The first heat dissipation opposing pattern 421 is formed at approximately the center of the substrate 4 in the lateral direction Y. One lead wire 311a of the first resistor 311 is inserted and connected to a through-hole 431 formed to open into the first heat dissipation opposing pattern 421, thereby electrically and thermally connecting the first heat dissipation opposing pattern 421 and the first resistor 311.

[0043] The second heat dissipation opposing pattern 422 is formed at the edge of the substrate 4 in the lateral direction Y. The other lead wire 311a of the first resistor 311 is inserted and connected to a through-hole 432 formed to open in the second heat dissipation opposing pattern 422, and the other lead wire 321a of the second resistor 321 is inserted and connected to a through-hole 433 formed to open in the second heat dissipation opposing pattern 422. In this way, the second heat dissipation opposing pattern 422 is electrically and thermally connected to the first resistor 311 and the second resistor 321. The first heat dissipation opposing pattern 421 and the second heat dissipation opposing pattern 422 have a shape in which the portion facing a conductive portion (for example, terminal fittings 5 ​​and conductive pattern 42) is cut out in order to ensure an insulating distance from a nearby conductive portion.

[0044] As shown in Figure 2, two heat dissipation patterns 423 are formed on the substrate 4 opposite to the heat sink 6, connected to each of the pair of lead wires 311a of the first resistor 311. These two heat dissipation patterns 423 also improve the heat dissipation of the first resistor 311.

[0045] As shown in Figure 3, four Zener diodes 312 are arranged on one side of the heat sink 6 in the lateral direction Y, aligned in the lateral direction Y. These four Zener diodes 312 are thermally connected to the heat sink 6 via heat dissipation opposing patterns 421, 422 and a heat transfer sheet 7.

[0046] As shown in Figures 4 to 6, the heat sink 6 is attached to the substrate 4 via a heat transfer sheet 7. One main surface of the heat transfer sheet 7 is in close contact with the surface of the substrate 4 that faces the heat sink 6, and the other main surface is in close contact with the surface of the heat sink 6 that faces the substrate 4. The heat transfer sheet 7 is made of a material that has high thermal conductivity and is easily deformable (for example, an elastically deformable rubber material such as silicone rubber). By making the heat transfer sheet 7 from an easily deformable material, the adhesion between the heat transfer sheet 7 and the substrate 4 and the heat sink 6 can be improved. For example, as shown in Figure 6, the heat sink 6 side of the substrate 4 has an uneven shape due to the formation of a conductive pattern 42 and the protruding tips of the pair of lead wires 311a of the first resistor 311. The heat transfer sheet 7 deforms along this uneven shape, thereby improving the adhesion between the heat transfer sheet 7 and the substrate 4.

[0047] The heat transfer sheet 7 is formed in a position that overlaps with the entire heat sink 6 in the substrate thickness direction X, and is also formed in a position that protrudes from the heat sink 6 on one side in the vertical direction Z (the side where the terminal fitting 5 is located). The heat transfer sheet 7 may, for example, have adhesive or bonding surfaces on both main surfaces, and the substrate 4 and heat sink 6 may be attached to both main surfaces. Alternatively, the heat transfer sheet 7 may have an extended portion that does not interfere with mounted components on the substrate 4, and may be fixed to the substrate 4 with bolts.

[0048] (Operation and effects of the first embodiment) In this embodiment, the heat sink 6 is positioned on the opposite side of the substrate 4 from at least one resistor, which is the heat dissipation resistor (in this embodiment, the first resistor 311 and the second resistor 321), and is positioned in the substrate thickness direction X to overlap with at least a portion of the heat dissipation resistor but not with the capacitor 322. Therefore, it is possible to promote heat dissipation from the heat dissipation resistor to the heat sink 6 while suppressing heat transfer from the heat sink 6 to the capacitor 322.

[0049] Furthermore, the heatsink 6 is positioned on the side of the substrate 4 opposite to the capacitor 322 side in the substrate thickness direction X. Therefore, heat transfer from the heatsink 6 to the capacitor 322 can be further suppressed.

[0050] Furthermore, on the heat sink 6 side of the substrate 4, heat dissipation opposing patterns 421 and 422 are formed that are thermally connected to the resistor to be heated and also face the heat sink 6. As a result, the heat from the resistor to be heated is spread to the heat dissipation opposing patterns 421 and 422 before being transferred to the heat sink 6, thereby improving the heat transfer efficiency from the resistor to be heated to the heat sink 6.

[0051] Furthermore, the heat sink 6 is thermally connected to the terminal fitting 5. Therefore, the heat from the heat sink 6 can be dissipated to the outside of the surge suppression device 1 (for example, the motor case in this embodiment) via the terminal fitting 5.

[0052] Furthermore, in a predetermined direction (vertical direction Z in this embodiment), the terminal fitting 5, the heat sink 6 and the resistor to be heated, and the capacitor 322 are arranged in this order. As mentioned above, the terminal fitting 5 is a relatively low-temperature component within the surge suppression device 1 because it facilitates heat dissipation to the outside of the surge suppression device 1. Therefore, by arranging the terminal fitting 5, the heat sink 6 and the resistor to be heated, and the capacitor 322 in this order as described above, the resistor to be heated can be positioned on the lower temperature side (terminal fitting 5 side), improving the heat dissipation performance of the resistor.

[0053] Furthermore, the surge suppression device 1 in this embodiment has a heat transfer sheet 7 that is in close contact with both the heat sink 6 and the substrate 4. Therefore, the formation of an air layer with low thermal conductivity between the heat sink 6 and the substrate 4 is suppressed, and the efficiency of heat transfer between the heat sink 6 and the substrate 4 is improved.

[0054] Furthermore, the Zener diode 312 is thermally connected to the heatsink 6. Therefore, the heat dissipation of the Zener diode 312 is improved.

[0055] Furthermore, leaded components (first resistor 311 and second resistor 321 in this embodiment) with lead wires 311a and 321a are mounted on the substrate 4, with the leaded components arranged on one side of the substrate 4 and the heatsink 6 arranged on the other side. As a result, the relatively tall leaded components are not placed on the side of the substrate 4 where the heatsink 6 is placed, making it easier to place the heatsink 6 over a relatively wide area of ​​the substrate 4, and preventing the heatsink 6 from interfering with the leaded components when it is placed.

[0056] As described above, this embodiment provides a surge suppression device that is less likely to transfer heat to the capacitor.

[0057] [Second Embodiment] Figure 7 is a rear view of the surge suppression device 1 in this embodiment. Figure 8 is an enlarged cross-sectional view of a part of the surge suppression device 1.

[0058] This embodiment is a modified version of the first embodiment in which the heat sink 6 is fixed to the substrate 4. The flat portion 61 of the heat sink 6 has an extended portion 611 that extends toward the terminal fitting 5 in the vertical direction Z from the region where the fin portion 62 is formed in the vertical direction Z. The extended portion 611 is formed at a position that overlaps with the first terminal portion 51 of the two terminal fittings 5. The extended portion 611 is fastened together with the substrate 4 and the terminal fitting 5 using bolts B and nuts N. In this way, the heat sink 6 of this embodiment is bolted to the substrate 4.

[0059] The other configurations of this embodiment are the same as those of the first embodiment. In addition, among the reference numerals used in the second embodiment and subsequent embodiments, those that are the same as those used in the previously described embodiments represent the same components, etc., as those in the previously described embodiments, unless otherwise specified.

[0060] (Operation and effects of the second embodiment) In this configuration, the heatsink 6 is fixed to the terminal fitting 5. This ensures that the heatsink 6 is firmly fixed in the surge suppression device 1, and also increases the contact between the heatsink 6 and the terminal fitting 5, thereby improving heat dissipation from the heatsink 6 to the terminal fitting 5. Furthermore, it has the same functions and effects as the first embodiment.

[0061] (Summary of the embodiments) Next, the technical concept understood from the embodiments described above will be described using the reference numerals and other symbols from the embodiments. However, the reference numerals and other symbols in the following description are not limited to the components in the claims that are specifically shown in the embodiments.

[0062] [1] A Zener diode (312), a capacitor (322) connected in parallel to the Zener diode (312), and in a closed circuit (3) including the Zener diode (312) and the capacitor (322), one or more resistors (311, 321) connected in series to the Zener diode (312) and the capacitor (322), and the Zener diode (312), the capacitor (322) and the one or more resistors (311, 321) are mounted A surge suppression device (1) comprises a substrate (4) and a heat sink (6) attached to the substrate (4), wherein the heat sink (6) is positioned on the opposite side of the substrate (4) from at least one of the resistors (311, 321) which are the heat dissipation targets (311, 321), and is positioned in the thickness direction (X) of the substrate (4) at a position that overlaps with at least a portion of the heat dissipation targets (311, 321) but does not overlap with the capacitor (322).

[0063] [2] The surge suppression device (1) according to [1], wherein the heat sink (6) is located on the side of the substrate (4) opposite to the capacitor (322) side in the thickness direction (X).

[0064] [3] The surge suppression device (1) according to [1] or [2], wherein the heat sink (6) side of the substrate (4) is thermally connected to the heat dissipation target resistors (311, 321) and has heat dissipation opposing patterns (421, 422) facing the heat sink (6).

[0065] [4] A surge suppression device (1) according to any one of [1] to [3], further comprising a terminal fitting (5) that is electrically connected to the outside, wherein the heat sink (6) is thermally connected to the terminal fitting (5).

[0066] [5] A surge suppression device (1) according to any one of [1] to [4], further comprising a terminal fitting (5) electrically connected to the outside, wherein the terminal fitting (5), the heat sink (6), the heat dissipation resistors (311, 321), and the capacitor (322) are arranged in this order in a predetermined direction (Z).

[0067] [6] The surge suppression device (1) according to any one of [1] to [5], further comprising a heat transfer sheet (7) that is in close contact with both the heat sink (6) and the substrate (4).

[0068] [7] The surge suppression device (1) according to any one of [1] to [6], wherein the Zener diode (312) is thermally connected to the heat sink (6).

[0069] [8] A surge suppression device (1) according to any one of [1] to [7], wherein a leaded mounted component having lead wires (311a, 321a) is mounted on the substrate (4), the leaded mounted component is arranged on one side of the substrate (4), and the heat sink (6) is arranged on the other side of the substrate (4).

[0070] (Note) Although embodiments of the present invention have been described above, the embodiments described herein do not limit the invention as defined in the claims. Furthermore, it should be noted that not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention. Moreover, the present invention can be implemented with appropriate modifications without departing from its spirit. [Explanation of Symbols]

[0071] 1… Surge suppression device 3...Closed circuit section 311...First resistor (resistor for heat dissipation) 311a... Lead wire 312... Zener diode 321...Second resistor (resistor for heat dissipation) 321a... Lead wire 322... Capacitor 4… Circuit board 421... Opposing pattern for heat dissipation 422... Opposing pattern for heat dissipation 5…Terminal fittings 6… Heatsink 7… Heat transfer sheet X...Thickness direction Z…Predetermined direction

Claims

1. A Zener diode and A capacitor connected in parallel with the Zener diode, In the closed circuit section including the Zener diode and the capacitor, one or more resistors are connected in series with the Zener diode and the capacitor, A substrate on which the Zener diode, the capacitor, and the one or more resistors are mounted, The substrate is equipped with a heat sink, The heat sink is positioned on the opposite side of the substrate from at least one of the resistors to be heated, and in the thickness direction of the substrate, it is positioned so as to overlap with at least a portion of the resistor to be heated but not with the capacitor. The heat sink is positioned on the side of the substrate opposite to the capacitor side in the thickness direction. Surge suppression device.

2. A Zener diode and A capacitor connected in parallel with the Zener diode, In the closed circuit section including the Zener diode and the capacitor, one or more resistors are connected in series with the Zener diode and the capacitor, A substrate on which the Zener diode, the capacitor, and the one or more resistors are mounted, The substrate is equipped with a heat sink, The heat sink is positioned on the opposite side of the substrate from at least one of the resistors to be heated, and in the thickness direction of the substrate, it is positioned so as to overlap with at least a portion of the resistor to be heated but not with the capacitor. On the heat sink side of the substrate, a heat dissipation counter pattern is formed which is thermally connected to the heat-dissipating resistor and faces the heat sink. Surge suppression device.

3. It further has terminal fittings that are electrically connected to the outside, The heat sink is thermally connected to the terminal fitting. The surge suppression device according to claim 1.

4. A Zener diode and A capacitor connected in parallel with the Zener diode, In the closed circuit section including the Zener diode and the capacitor, one or more resistors are connected in series with the Zener diode and the capacitor, A substrate on which the Zener diode, the capacitor, and the one or more resistors are mounted, The substrate is equipped with a heat sink, The heat sink is positioned on the opposite side of the substrate from at least one of the resistors to be heated, and in the thickness direction of the substrate, it is positioned so as to overlap with at least a portion of the resistor to be heated but not with the capacitor. It further has terminal fittings that are electrically connected to the outside, In a predetermined direction, the terminal fitting, the heat sink and the heat dissipation resistor, and the capacitor are arranged in this order. Surge suppression device.

5. The heat sink and the substrate further have a heat transfer sheet that is in close contact with each other. The surge suppression device according to claim 1.

6. The Zener diode is thermally connected to the heat sink. The surge suppression device according to claim 1.

7. A Zener diode and A capacitor connected in parallel with the Zener diode, In the closed circuit section including the Zener diode and the capacitor, one or more resistors are connected in series with the Zener diode and the capacitor, A substrate on which the Zener diode, the capacitor, and the one or more resistors are mounted, The substrate is equipped with a heat sink, The heat sink is positioned on the opposite side of the substrate from at least one of the resistors to be heated, and in the thickness direction of the substrate, it is positioned so as to overlap with at least a portion of the resistor to be heated but not with the capacitor. The aforementioned circuit board has leaded components mounted on it, The leaded component is arranged on one side of the substrate, and the heat sink is arranged on the other side of the substrate. Surge suppression device.

Images