Heat medium heating device

Abstract

To provide a heat medium heating device capable of maintaining a plurality of power switching elements for controlling energization of an electric heater at an appropriate temperature even when a direction in which a heat medium flows is reversed.SOLUTION: The heat medium heating device 1 includes a plurality of electric heaters for heating the heat medium flowing through the heat medium passage, and a plurality of power switching elements 22 to 24 for controlling energization of the electric heaters. The plurality of power switching elements 22 to 24 are disposed between the plurality of electric heaters, and the power switching elements 22 to 24 are disposed so as to be able to exchange heat with the heat medium flowing between the plurality of electric heaters disposed in series with respect to the flow of the heat medium.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a heat medium heating device that uses an electric heater to heat a heat medium flowing through a heat medium flow path. [Background technology]

[0002] Conventionally, heat medium heating devices used for air conditioning the interior of a vehicle have a heat medium flow path formed in a housing, and a cylindrical electric heater called a cartridge heater is arranged in this heat medium flow path to heat the heat medium flowing through the heat medium flow path. In this case, a plurality of (for example, two) heat medium flow paths are provided in the housing, one end of which is connected by a communication path, and an electric heater is arranged in each heat medium flow path, and the heat medium flowing in from an inlet at the other end of one heat medium flow path is heated by each electric heater, and then flows out from an outlet at the other end of the other heat medium flow path (see, for example, Patent Document 1 and Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2016-536197 [Patent Document 2] CN109186074B Summary of the Invention [Problem to be solved by the invention]

[0004] Here, the current supply to each electric heater is controlled using a power switching element such as an IGBT or SIC, but it is also possible to provide an additional power switching element to adjust the overall power of the two electric heaters. In this case, the currents flowing through each power switching element will join together and flow in the power switching element that adjusts the overall power, which will generate the most heat and may cause a malfunction.

[0005] Therefore, these power switching elements need to be cooled with a heat medium. In this case, the power switching elements can be cooled effectively by exchanging heat between the power switching elements and a heat medium with as low a temperature as possible. Therefore, ideally, the power switching elements would be located near the inlet of one of the heat medium flow paths mentioned above.

[0006] However, depending on the layout of the heat medium heating device in the vehicle, it may be necessary to use the other end of the other heat medium flow path as the inlet and the other end of one heat medium flow path as the outlet, which has the disadvantage that in such cases the power switching element also needs to be moved to the inlet of the other heat medium flow path.

[0007] The present invention has been made to solve the above-mentioned conventional technical problems, and aims to provide a heat medium heating device that can maintain a plurality of power switching elements that control the current supply to an electric heater at an appropriate temperature even when the flow direction of the heat medium is reversed. [Means for solving the problem]

[0008] In order to solve the above problems, the heat medium heating device of the present invention comprises a plurality of electric heaters that heat the heat medium flowing through a heat medium flow path, and a plurality of power switching elements that control the supply of electricity to these electric heaters, wherein the plurality of power switching elements are arranged between the plurality of electric heaters, and at least some of the power switching elements are arranged so as to be able to exchange heat with the heat medium flowing between the plurality of electric heaters that are arranged in series with respect to the flow of the heat medium.

[0009] A heat medium heating device according to a second aspect of the present invention is characterized in that, among the plurality of power switching elements in the above-mentioned invention, a power switching element that generates a larger amount of heat than the others is arranged so as to be able to exchange heat with the heat medium flowing between a plurality of electric heaters that are arranged in series with respect to the flow of the heat medium.

[0010] A heat medium heating device according to a third aspect of the present invention is characterized in that it comprises power switching elements for controlling the energization of each of the plurality of electric heaters in the above-mentioned invention, and a specific power switching element through which currents flowing through the power switching elements are joined together, and the specific power switching element is arranged so as to be able to exchange heat with the heat medium flowing between the plurality of electric heaters arranged in series with respect to the flow of the heat medium.

[0011] A heat medium heating device according to a fourth aspect of the present invention comprises at least two heat medium flow paths arranged in parallel with a gap between them, a communicating flow path connecting one ends of the heat medium flow paths, and a heat medium inlet / outlet portion formed at the other end of each heat medium flow path, wherein an electric heater is disposed in each heat medium flow path, and a connection terminal of each electric heater is drawn out from one end of the heat medium flow path, and the plurality of power switching elements are disposed so as to be able to exchange heat with the heat medium flowing through the communicating flow path.

[0012] A fifth aspect of the present invention is a heat medium heating device according to the above-mentioned invention, characterized in that the heat medium flow paths and the communicating flow paths are provided in a housing, and the heat medium heating device further comprises a control board provided in the housing and arranged to cover the spaces between the heat medium flow paths, and a plurality of power switching elements are arranged in the spaces, and the connection terminals of the electric heaters and the plurality of power switching elements are electrically connected to the control board. [Effects of the Invention]

[0013] According to the present invention, in a heat medium heating device including a plurality of electric heaters for heating the heat medium flowing through a heat medium flow path and a plurality of power switching elements for controlling the energization of these electric heaters, the plurality of power switching elements are arranged between the plurality of electric heaters, so that the dead space between each electric heater can be effectively used for arranging the plurality of power switching elements, thereby realizing a miniaturization of the heat medium heating device.

[0014] In particular, since at least some of the power switching elements are arranged to be able to exchange heat with the heat medium flowing between the electric heaters arranged in series with respect to the heat medium flow, even if the heat medium flow is reversed, the appropriate temperature can be maintained without changing the position of the power switching elements, thereby improving the versatility of the layout of the heat medium heating device.

[0015] In this case, as in the second aspect of the invention, among the multiple power switching elements, a power switching element that generates more heat than the others, for example, a power switching element for controlling the current supply to each of the multiple electric heaters as in the third aspect of the invention, and a specific power switching element among the specific power switching elements through which the currents flowing through each power switching element are joined together, are arranged so that they can exchange heat with the heat medium flowing between the multiple electric heaters that are arranged in series with respect to the flow of the heat medium, so that even if the flow of the heat medium is reversed, the power switching element that generates more heat can be cooled efficiently and reliably.

[0016] This makes it possible to maintain all the power switching elements in an appropriate temperature range, thereby making it possible to avoid breakdowns in the power switching elements.

[0017] In this case, as in the fourth aspect of the present invention, when there are at least two heat medium flow paths arranged side by side with a gap between them, a communicating flow path connecting one ends of the heat medium flow paths, and a heat medium inlet / outlet portion formed at the other end of each heat medium flow path, and an electric heater is disposed in each heat medium flow path, by drawing out the connection terminal of each electric heater from one end of the heat medium flow path and arranging multiple power switching elements so that they can exchange heat with the heat medium flowing in the communicating flow path, the electrical connection positions of each electric heater and the multiple power switching elements become closer to each other, and the degree of freedom in designing the wiring pattern is improved.

[0018] For example, as in the fifth aspect of the present invention, when the heat medium flow paths and the connecting flow paths are provided in a housing and a control board is provided in this housing so as to cover the spaces between the heat medium flow paths, by arranging multiple power switching elements in the spaces, the space in the housing can be effectively used for arranging the multiple power switching elements.

[0019] Furthermore, since the connection terminals of each electric heater and the plurality of power switching elements can be electrically connected to the control board in close proximity, the degree of freedom in designing the pattern of the control board can be improved. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a perspective view showing the appearance of a heat medium heating device according to an embodiment of the present invention; [Figure 2] 2 is a schematic cross-sectional plan view illustrating a flow path of a heat medium in the heat medium heating device of FIG. 1. FIG. [Figure 3] FIG. 2 is a plan view showing the inside of the heat medium heating device of FIG. 1 (with a control board seen through). [Figure 4] FIG. 2 is a vertical cross-sectional side view of the heat medium heating device of FIG. [Figure 5] 2 is an enlarged schematic view illustrating the mounting structure of the power switching element of the heat medium heating device of FIG. 1. FIG. [Figure 6] 2 is a schematic enlarged view illustrating the vibration-resistant structure of a condenser of the heat medium heating device of FIG. 1. FIG. [Figure 7] FIG. 7 is a view of FIG. 6 as seen from the opposite side to the control board. [Figure 8] FIG. 2 is a circuit block diagram of a control device for the heat medium heating device of FIG. [Figure 9] 1. FIG. 4 is an enlarged view illustrating another vibration-resistant structure of the condenser of the heat medium heating device of FIG. [Figure 10] This is a view of FIG. 9 as seen from the opposite side to the control board. [Figure 11] 1. FIG. 4 is an enlarged view illustrating yet another vibration-resistant structure of the condenser of the heat medium heating device of FIG. [Figure 12]This is a view of FIG. 11 as seen from the opposite side to the control board. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a perspective view showing the appearance of a heat medium heating device 1 according to an embodiment of the present invention, Fig. 2 is a schematic cross-sectional plan view illustrating the flow of heat medium within the heat medium heating device 1, Fig. 3 is a plan view showing the inside of the main body 3 of the housing 2 with the cover 4 of the heat medium heating device 1 of Fig. 1 removed and the control board 21 seen through, and Fig. 4 is a vertical cross-sectional side view of the heat medium heating device 1 with the cover 4 removed.

[0022] (1) Heat medium heating device 1 The heat medium heating device 1 of the embodiment is used to air-condition the interior of a vehicle (not shown), and has a housing 2 made of a main body 3 made of a metal having high thermal conductivity, such as iron or aluminum, and a cover 4 also made of metal attached to the main body 3. The main body 3 of the housing 2 is provided with a plurality of (two in the embodiment) flow path sections 6, 7 (also made of metal) spaced apart from each other at a distance 8, which form part of the main body 3, and within which heat medium flow paths 9, 11 are respectively formed. That is, the heat medium flow paths 9, 11 are arranged side by side within the housing 2, spaced apart from each other at the distance 8.

[0023] A communication section 13 having a communication flow path 12 formed therein is connected to one end of the flow path sections 6, 7, and constitutes part of the main body 3, and one end of both heat medium flow paths 9, 11 are connected to this communication flow path 12. Inlet / outlet sections 16, 17 for allowing the heat medium to flow in / out are configured to be connected to the other end of each heat medium flow path 9, 11, respectively.

[0024] In the following embodiment, the heat medium flows into the inlet / outlet portion 16 of one heat medium flow path 9 and flows out from the inlet / outlet portion 17 of the other heat medium flow path 11. That is, in the embodiment, the heat medium flows into the heat medium flow path 9 from the inlet / outlet portion 16, enters the heat medium flow path 11 through the communication flow path 12, and flows out from the inlet / outlet portion 17. However, depending on the installation layout of the heat medium heating device 1 on the vehicle, the heat medium may flow into the inlet / outlet portion 17 of the other heat medium flow path 11 and flow out from the inlet / outlet portion 16 of one heat medium flow path 9.

[0025] In each figure, 18 and 19 are rod-shaped electric heaters (heat generating elements) constituted by cartridge heaters (cylindrical heaters) in this embodiment, and electric heater (electric heater 1) 18 is inserted into one heat medium flow path 9 with a gap between it and the inner surface of flow path section 6, while electric heater (electric heater 2) 19 is inserted into the other heat medium flow path 11 with a gap between it and the inner surface of flow path section 7. As a result, the electric heaters 18, 19 are arranged in series with respect to the flow of the heat medium, and the communicating flow path 12 in the communicating section 13 is located between the electric heaters 18, 19.

[0026] In this embodiment, a connection terminal 18A of the electric heater 18 is drawn out from the flow path section 6 at one end of the heat medium flow path 9, and a connection terminal 19A of the electric heater 19 is drawn out from the flow path section 7 at one end of the heat medium flow path 11. Sockets 43, 44 (FIG. 1) are attached to the respective connection terminals 18A, 19A from the outside, and the connection terminals are electrically connected to a control board 21, which will be described later, via the sockets 43, 44.

[0027] A control board 21 is attached to the cover 4 side of each of the flow passage sections 6, 7 in the main body 3 so as to cover the gap 8. Mounted on this control board 21 are a power switching element 22 (IGBT1) for controlling the supply of electricity to the electric heater 18, a power switching element 23 (IGBT2) for controlling the supply of electricity to the electric heater 19, and a power switching element 24 (IGBT3) for adjusting the overall power of each of the electric heaters 18, 19. In the embodiment, the plurality of power switching elements 22 to 24 are configured by IGBTs, but they may also be configured by SICs.

[0028] Also mounted on control board 21 are capacitor 26 (a smoothing capacitor made of a film capacitor) as a first electronic component with relatively low vibration resistance, and coil 27 (a common mode coil) as a second electronic component with relatively high vibration resistance that constitutes noise filter 25. Capacitor 26 and coil 27 are electronic components larger in size than power switching elements 22 to 24. These power switching elements 22 to 24, capacitor 26, coil 27, etc. constitute control device 31 (FIG. 8) for controlling electric heaters 18, 19, etc. of heat medium heating device 1.

[0029] (2) Mounting structure of power switching elements 22 to 24 Next, the mounting structure of each of the power switching elements 22 to 24 will be described with reference to Figures 3 to 5. In this embodiment, all of the power switching elements 22 to 24 are arranged within the gap 8 and are mounted in a heat exchange manner with the communicating part 13 via an insulating heat transfer sheet 46. As a result, each of the power switching elements 22 to 24 is arranged so as to be able to exchange heat with the heat medium flowing in the communicating flow path 12, i.e., the heat medium flowing between the electric heaters 18 and 19.

[0030] In this embodiment, each of the power switching elements 22 to 24 is pressed against the communication portion 13 via a heat transfer sheet 46 by a fixed leaf spring 47 screwed to the main body 3. In this embodiment, as shown enlarged in Fig. 5, heat dissipation grease 48 is provided around the power switching elements 22 to 24 to improve heat dissipation (not shown in Fig. 3). However, this heat dissipation grease 48 does not have to be provided.

[0031] In particular, as will be described later, the currents flowing through power switching element 22 (IGBT1) and power switching element 23 (IGBT2) join together and flow, and power switching element 24 (IGBT3: at least some specific power switching elements) which generates the greatest amount of heat is disposed in correspondence with the center of communication flow path 12. As a result, power switching element 24 is disposed in a location where the temperature of the heat medium flowing in from inlet / outlet portion 16 and flowing out from inlet / outlet portion 17 is at the median value.

[0032] In the embodiment, the other power switching elements 22, 23 are also arranged in parallel on both sides of the power switching element 24, but this is not limiting, and the power switching elements 22, 23 may be arranged in a heat exchange relationship with the heat medium flowing through the heat medium flow paths 9, 11 in the flow path portion 6 and the flow path portion 7. The connection terminals of the power switching elements 22 to 24 (the connection terminal of the power switching element 23 is indicated by 23A in FIG. 4, and the connection terminal of the power switching element 24 is indicated by 24A in FIG. 5) are located on the control board 21 side and are electrically connected to the control board 21.

[0033] (3) Vibration-resistant structure of capacitor 26 Next, the vibration-resistant structure of capacitor (first electronic component) 26 will be described with reference to Figures 3, 4, 6, and 7. Capacitor 26 and coil 27 are mounted adjacent to each other on the surface of control board 21 on the side of each of flow path sections 6 and 7, and are inserted and disposed within space 8 between flow path section 6 (heat medium flow path 9) and flow path section 7 (heat medium flow path 11) (Figures 3 and 4).

[0034] In this embodiment, coil 27 (second electronic component), which is a common mode coil, has four lead portions 27A corresponding to the ends of the primary and secondary windings (shown as 49P and 49S in FIG. 7 ), and each lead portion 27A is connected to control board 21, so that it has relatively high vibration resistance. On the other hand, lead portion 26A of capacitor 26 (first electronic component) is also connected to control board 21, but since there are only two lead portions, its vibration resistance is relatively low. In particular, when heat medium heating device 1 is mounted on a vehicle, vibrations are likely to be applied, and while the control board 21 side of capacitor 26 has a small amplitude, the portion opposite to control board 21 has a large amplitude in the direction perpendicular to the line connecting the two lead portions 26A.

[0035] That is, coil 27 has higher vibration resistance than capacitor 26. Therefore, capacitor 26 is first placed near coil 27, and coil 27 is placed in a direction in which the line connecting two lead portions 26A of capacitor 26 intersects at right angles. Meanwhile, coil 27 typically includes a core (not shown) and a hard resin case 51 that houses this core, and the aforementioned windings 49P, 49S are wound around this case 51. In this embodiment, a plurality of (two in this embodiment) protrusions 52, 53 are formed integrally with case 51.

[0036] These protrusions 52, 53 protrude from coil 27 toward capacitor 26, and their tips abut against or are close to capacitor 26. Joining members 54 are provided between these protrusions 52, 53 and the portion of capacitor 26 opposite control board 21, respectively, to join capacitor 26 and coil 27. In this embodiment, these joining members 54 are made of a two-component curing resin such as epoxy resin, and are applied between each of protrusions 52, 53 and capacitor 26.

[0037] (4) Control device 31 Next, Fig. 8 shows a circuit block of the control device 31. The coil 27 that constitutes the noise filter 25 described above is connected to the vehicle battery (DC power source) (not shown), and the capacitor 26 is connected downstream of this coil 27. The power switching element 22 and the electric heater 18 are connected in series, and the power switching element 23 and the electric heater 19 are connected in series, with these two series circuits being connected in parallel. The power switching element 24 is connected in series to these parallel circuits, and a current sensor 32 is connected in series to the power switching element 24.

[0038] The power switching elements 22 and 23 are connected to the positive electrode side of the capacitor 26, and the current sensor 32 is connected to the negative electrode side. As a result, the currents that flow through the two power switching elements 22 and 23 join together and flow through the power switching element 24.

[0039] 8, reference numeral 36 denotes a control unit configured from a microcomputer, and drivers 37, 38, and 39 are connected to the output of this control unit 36. Driver 37 is connected to the gate of power switching element 22, and driver 38 is connected to the gate of power switching element 23. Driver 39 is connected to the gate of power switching element 24.

[0040] The control unit 36 ​​receives the output of the current sensor 32, as well as the outputs of the inlet temperature sensor 41 and the outlet temperature sensor 42. In this embodiment, the inlet temperature sensor 41 detects the temperature of the heat medium flowing into the heat medium flow path 9 from the inlet / outlet portion 16, and the outlet temperature sensor 42 detects the temperature of the heat medium flowing out from the inlet / outlet portion 17. In this application, the heat medium flowing in from the inlet / outlet portion 16 means the heat medium just before or just after entering the inlet / outlet portion 16, and the heat medium flowing out from the inlet / outlet portion 17 means the heat medium just before or just after exiting the inlet / outlet portion 17.

[0041] (5) Operation of the Heat Medium Heating Device 1 Next, we will explain the operation of the heat medium heating device 1 with the above configuration. A heat medium circuit (not shown) is connected to the inlet / outlet portion 16, and a heat medium (water in this embodiment) is caused to flow into the heat medium flow path 9 from the inlet / outlet portion 16 by a pump (not shown). The heat medium that has flowed into the heat medium flow path 9 flows into the heat medium flow path 11 via the communication flow path 12, and then flows out from the inlet / outlet portion 17 to the heat medium circuit described above.

[0042] Meanwhile, the control unit 36 ​​of the control device 31 controls the switching of the power switching elements 22 to 24 using the drivers 37 to 39 based on the outputs of the inlet temperature sensor 41, the outlet temperature sensor 42, and the current sensor 32. As a result, the electric heaters 18, 19 are energized and generate heat, so that the heat medium that has flowed into the heat medium flow path 9 is heated as it passes around the electric heater 18, enters the heat medium flow path 11 via the communication flow path 12, and is further heated as it passes around the electric heater 19.

[0043] A heater core disposed in the HV unit of the vehicle is connected to the heat medium circuit, and the heat medium heated by the heat medium heating device 1 is circulated through this heater core. Air supplied to the vehicle cabin is passed through the heater core, thereby heating the cabin.

[0044] The control unit 36 ​​controls the switching of the power switching elements 22, 23 based on the temperature of the inflowing heat medium detected by the inlet temperature sensor 41 and the temperature of the outflowing heat medium detected by the outlet temperature sensor 42, and controls the supply of electricity to each of the electric heaters 18, 19. The currents that flow through these power switching elements 22, 23 (electric heaters 18, 19) join together and flow to a power switching element (specific power switching element) 24. Based on the value of this joined current detected by the current sensor 32, the control unit 36 ​​controls the switching of the power switching element 24 to adjust the overall power of each of the electric heaters 18, 19.

[0045] Here, the currents flowing through the power switching elements 22 and 23 join together and flow through the power switching element 24 (specific power switching element), so the power switching element 24 generates more heat than the power switching elements 22 and 23, and the amount of heat generated becomes the largest.

[0046] (6) Effects of the arrangement of the heat medium flow paths 9, 11, the communication flow path 12, and the power switching elements 22 to 24 As described above, the plurality of power switching elements 22 to 24 are arranged between the plurality of electric heaters 18, 19, so that the dead space between each electric heater 18, 19 can be effectively utilized for arranging the plurality of power switching elements 22 to 24, thereby realizing miniaturization of the heat medium heating device 1.

[0047] In particular, in this embodiment, the power switching elements 22 to 24 are arranged so as to be able to exchange heat with the heat medium flowing between the plurality of electric heaters 18, 19 arranged in series with respect to the flow of the heat medium, so that, unlike the above-described embodiment, even if the flow of the heat medium is reversed in the layout of the heat medium heating device 1 into the vehicle, such that the heat medium flows in from the inlet / outlet section 17 and flows out from the inlet / outlet section 16, the appropriate temperature can be maintained without changing the positions of the power switching elements 22 to 24. This improves the versatility of the layout of the heat medium heating device 1.

[0048] In this case, in the embodiment, among the plurality of power switching elements 22 to 24, a specific power switching element 24 that generates more heat than the others is arranged so as to be able to exchange heat with the heat medium flowing through the communication flow path 12 between the plurality of electric heaters 18, 19 that are arranged in series with respect to the flow of the heat medium. Therefore, even if the flow of the heat medium is reversed, the power switching element 24 that generates more heat is cooled efficiently and reliably.

[0049] This makes it possible to maintain all of the power switching elements 22 to 24 in an appropriate temperature range, and prevents breakdowns in the power switching elements 22 to 24.

[0050] Furthermore, in this embodiment, the connection terminals 18A, 19A of the electric heaters 18, 19 are drawn out from one end of the heat medium flow paths 9, 11, and the plurality of power switching elements 22-24 are arranged so as to be able to exchange heat with the heat medium flowing through the communicating flow path 12, so that the electrical connection positions of the electric heaters 18, 19 and the plurality of power switching elements 22-24 are close to each other. This allows the connection terminals 18A, 19A of the electric heaters 18, 19 and the plurality of power switching elements 22-24 to be electrically connected to the control board 21 in close positions, improving the design freedom of the wiring pattern of the control board 21.

[0051] (7) Effect of the vibration-resistant structure of capacitor 26 Furthermore, a capacitor 26 (first electronic component) having a relatively low vibration resistance and a coil 27 (second electronic component) having a relatively higher vibration resistance than the capacitor 26 are mounted adjacent to each other on the control board 21, and a joining member 54 is provided to join the part of the capacitor 26 opposite the control board 21 to the coil 27, thereby making it possible to improve the vibration resistance of the capacitor 26, which has a low vibration resistance.

[0052] 6, it is possible to reduce the amplitude of vibration at the portion of capacitor 26 opposite to control board 21. This makes it possible to prevent lead portion 26A of capacitor 26, which is joined to control board 21, from being damaged by vibration, making it extremely suitable for vehicle-mounted heat medium heating device 1, which requires high vibration resistance.

[0053] In particular, because the portion of capacitor 26 opposite control board 21 where the amplitude of vibration is large is joined to coil 27 by joining member 54, it is possible to obtain high vibration resistance with a smaller amount of joining member 54 than when joining control board 21 and capacitor 26 with joining member 54. Furthermore, because capacitor 26 is fixed to coil 27 by joining member 54 at a position away from control board 21, even if joining member 54 made of two-component curing resin drips as in the embodiment, it is less likely to adhere to control board 21, and the inconvenience of restrictions on the pattern design of control board 21 can be eliminated.

[0054] In particular, in the embodiment, a two-component curing resin is used as the joining member 54, which makes it easy to join the capacitor 26 and the coil 27, and after the joining member 54 hardens, the joint between the capacitor 26 and the coil 27 will not be damaged by vibration, improving the ease of assembly and vibration resistance. Furthermore, the use of a two-component curing resin shortens the holding time until hardening, thereby improving productivity.

[0055] Furthermore, in the embodiment, multiple protrusions 52, 53 are formed on the coil 27 that protrude toward the capacitor 26, and a joining member 54 is provided between each of the protrusions 52, 53 and the capacitor 26. This makes it possible to easily and stably fix the capacitor 26 and the coil 27 with the joining member 54 by bridging the protrusions 52, 53 between the coil 27, which has a relatively high vibration resistance, and the capacitor 26, which has a low vibration resistance.

[0056] (8) Another example of the vibration-resistant structure of capacitor 26 Next, another example of the vibration-resistant structure of capacitor (first electronic component) 26 will be described with reference to Figures 9 and 10. Note that in each figure, parts denoted by the same reference numerals as in Figures 6 and 7 have the same or similar functions. In this embodiment, the tips of two protrusions 52, 53 in Figures 6 and 7 are connected by a connecting portion 56. Then, this connecting portion 56 is placed opposite (in contact with or close to) capacitor 26, and a bonding material 54 is applied between this connecting portion 56 and capacitor 26.

[0057] With this configuration, it becomes relatively easy to manage the application position of the joining material 54, and the joining material 54 can join the capacitor 26 and the coil 27 with a line rather than a point, making it possible to stably fix the capacitor 26 and the coil 27 with a smaller amount of joining material 54.

[0058] (9) Another example of the vibration-resistant structure of capacitor 26 Next, another example of the vibration-resistant structure of capacitor 26 will be described with reference to Figures 11 and 12. In each figure, the same reference numerals as in Figures 6, 7, 9, and 10 denote the same or similar functions. In this embodiment, one protrusion 57 protrudes from case 51 of coil 27 toward capacitor 26.

[0059] 12, a widened portion 58 is formed at the tip of the protrusion 57. The widened portion 58 is also located close to or in contact with the capacitor 26 and faces the capacitor 26. A joining member 54 is provided between the widened portion 58 and the capacitor 26.

[0060] Even with this configuration, it is relatively easy to manage the application position of joining material 54, and it becomes possible to join capacitor 26 and coil 27 with a wire using joining material 54. In particular, in this case, a single protrusion 57 or a smaller number of protrusions than in the examples of Figures 6 and 9 is sufficient, so there is less need to change the shape of case 51 of coil 27.

[0061] In the embodiment, the capacitor 26 is used as the first electronic component having a relatively low vibration resistance, and the coil 27 is used as the second electronic component having a relatively high vibration resistance, but the present invention is not limited to this and is also effective in combination with other electronic components within the scope of the present invention.

[0062] In addition, in the embodiment, an inlet temperature sensor 41 and an outlet temperature sensor 42 are provided to control the power supply to the electric heaters 18, 19, but control may also be performed using only the inlet temperature sensor 41, or only the outlet temperature sensor 42, or a temperature sensor that detects the temperature (median) of the heat medium flowing through the communicating flow path 12.

[0063] Furthermore, although the embodiment has been described as having two heat medium flow paths 9 and 11, the present invention is also effective when more heat medium flow paths are configured and arranged at a distance from each other. Also, although the embodiment has been described as having IGBTs for the power switching elements 22 to 24, they may be configured as MOSFETs, SICs, etc.

[0064] Furthermore, in the embodiment, the heat medium heating device used for air conditioning of a vehicle has been taken as an example and explained, but the present invention is not limited to this and is effective for heat medium heating devices in various heating systems. [Explanation of symbols]

[0065] 1 Heat medium heating device 2. Case 8 intervals 9, 11 Heat transfer medium flow path 12 Connecting flow path 16, 17 Entrance / exit section 18, 19 Electric heater 21 Control board 22-24 Power switching elements 26 Capacitor (first electronic component) 26A, 27A lead part 27 Coil (secondary electronic component) 31 Control device 32 Current Sensor 36 Control Unit 41 Inlet temperature sensor 42 Outlet temperature sensor 52, 53, 57 Protrusion 54 Joint members 56 Connecting part 58 Widening section

Claims

1. A heat medium heating device including a plurality of electric heaters for heating a heat medium flowing through a heat medium flow path, and a plurality of power switching elements for controlling the energization of the electric heaters, the plurality of power switching elements are disposed between the plurality of electric heaters, a heat medium heating device, characterized in that at least some of the power switching elements are arranged to be able to exchange heat with the heat medium flowing between the plurality of electric heaters arranged in series with respect to the flow of the heat medium;

2. 2. The heat medium heating device according to claim 1, wherein, among the plurality of power switching elements, a power switching element that generates a larger amount of heat than the others is arranged so as to be able to exchange heat with the heat medium flowing between the plurality of electric heaters that are arranged in series with respect to the flow of the heat medium.

3. The power switching element controls the energization of each of the plurality of electric heaters, and a specific power switching element through which currents flowing through the power switching elements join together, 3. The heat medium heating device according to claim 2, wherein the specific power switching element is arranged so as to be able to exchange heat with the heat medium flowing between the plurality of electric heaters arranged in series with respect to the flow of the heat medium.

4. The heat transfer device includes at least two heat transfer medium flow paths arranged in parallel with each other at an interval, a communication flow path connecting one end of each heat transfer medium flow path, and a heat transfer medium inlet / outlet portion formed at the other end of each heat transfer medium flow path, the electric heater is disposed in each of the heat medium flow paths, and a connection terminal of each electric heater is drawn out from one end of the heat medium flow path; 2. The heat medium heating device according to claim 1, wherein the plurality of power switching elements are arranged so as to be able to exchange heat with the heat medium flowing through the communication flow path.

5. the heat medium flow paths and the communication flow paths are provided in a housing, and a control board is provided in the housing and arranged to cover the spaces between the heat medium flow paths; the plurality of power switching elements are arranged within the intervals, 5. The heat medium heating device according to claim 4, wherein the connection terminals of the electric heaters and the plurality of power switching elements are electrically connected to the control board.

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