Structure, inverter module, motor, and method for manufacturing structure

Abstract

Provided is a structure (bus bar module (10)) comprising: a bus bar (30) which is made of a conductive metal and which is electrically connected to a power module (101) that has a plurality of semiconductor elements (120) and that converts current between DC and AC; and a bus bar sealing part (40) that seals at least a part of the bus bar (30) with a resin cured product obtained by curing a thermosetting resin.

Description

[Technical Field]

[0001] The present invention relates to a structure, an inverter module, a motor, and a method for manufacturing the structure. [Background technology]

[0002] In recent years, there has been a shift from internal combustion engines to motors as a power source for vehicles such as automobiles. Generally, such motors are provided with a motor body and an inverter device (inverter module) (see Patent Document 1). A bus bar is arranged between the motor body and the inverter device to accommodate the flow of a relatively large current. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-173739 Summary of the Invention [Problem to be solved by the invention]

[0004] As motors become more powerful, the current flowing through bus bars also increases. As a result, there are concerns that heat generated by the bus bars may adversely affect elements in inverter devices. This type of bus bar is used not only between the motor body and the inverter device, but also between various other components, and there are similar concerns that heat generated may adversely affect the components.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a technique for effectively dissipating heat generated by a bus bar. [Means for solving the problem]

[0006] According to the present invention, the following techniques are provided. (1) a bus bar made of a conductive metal and electrically connected to a power module having a plurality of semiconductor elements and performing current conversion between direct current and alternating current; a bus bar sealing portion in which at least a portion of the bus bar is sealed with a cured resin product obtained by curing a thermosetting resin; A structure having: (2) The structure according to (1), wherein the thermosetting resin comprises an epoxy resin or a phenolic resin. (3) The structure according to (1) or (2), wherein the cured resin has a thermal conductivity of 1 W / mK or more and 5 W / mK or less. (4) The structure according to any one of (1) to (3), wherein the cured resin has a linear expansion coefficient of 50 ppm / K or less at a temperature equal to or lower than the glass transition temperature. (5) a current sensor for detecting a current flowing through the bus bar; The structure according to any one of (1) to (4), wherein the current sensor is sealed in the cured resin. (6) The structure according to (5), wherein the current sensor is a Hall element coreless current sensor. (7) The structure according to any one of (1) to (6), wherein the bus bar sealing portion has a bus bar cooling passage for cooling the bus bar. (8) The structure according to any one of (1) to (7), wherein the structure is provided in an AC path through which an AC current flows between the power module and a stator of a rotating electrical machine. (9) The structure according to any one of (1) to (7), wherein the structure is provided in a DC path through which a DC current flows between the power module and the smoothing module. (10) a power module having a plurality of semiconductor elements for converting power between direct current and alternating current; a DC path connected to the power module through which a DC current flows; a smoothing module provided in the DC path for smoothing the DC current; an AC path connected to the power module through which an AC current flows, An inverter module in which a rotating electric machine is connected to the AC path, An inverter module having the structure according to any one of (1) to (9) between the power module and the smoothing module in the DC path or in the AC path. (11) an inverter cooling flow path that cools the inverter module; a bus bar cooling channel for cooling the bus bar of the structure, The inverter module according to (10), wherein the inverter cooling passage and the bus bar cooling passage are configured in common. (12) A motor having the inverter module (10) or (11) and a motor body to which power is supplied from the inverter module. (13) A method for producing the structure according to any one of (1) to (9), a bus bar sealing step of sealing at least a portion of a bus bar made of a conductive metal with a thermosetting resin; The manufacturing method, wherein the bus bar sealing step is performed by compression molding or transfer molding. (14) The bus bar sealing step is performed by compression molding, the bus bar has a through hole penetrating near an end portion, The manufacturing method according to (13), wherein a positioning protrusion for fitting the through hole of the bus bar is provided inside a mold used for the compression molding. (15) The manufacturing method according to (14), wherein the molding pressure in the compression molding in the bus bar sealing step is 20 MPa or less. (16) The method according to any one of (13) to (15), wherein the thermosetting resin includes an epoxy resin or a phenolic resin. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technique for effectively dissipating heat generated by a bus bar. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a motor according to an embodiment. [Figure 2] FIG. 1 is a cross-sectional view of a motor according to an embodiment. [Figure 3] FIG. 2 is a plan view of the bus bar module according to the embodiment. [Figure 4] FIG. 2 is a cross-sectional view of the bus bar module according to the embodiment. [Figure 5] 1 is a flowchart illustrating a method for manufacturing a bus bar module according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Summary> An embodiment of the present invention will be described with reference to the drawings. This embodiment provides a technology suitable for e-Axle motors, achieving a low profile, compact size, improved insulation, cooling capabilities, and stable operation. To achieve this, a structure (hereinafter also referred to as a "busbar module") is used in which busbars used in inverter modules (also referred to as "inverter devices") are sealed with a highly thermally conductive resin (mainly epoxy resin) and the components are modularized (or integrated into a circuit board). The following describes examples in which the busbars are applied to inverter busbars (motor input / output busbars) that connect the inverter module to the motor body, and smoothing capacitor busbars that connect the power module to a smoothing capacitor. Cooling such busbars improves the thermal environment within the motor, enabling stable operation of the power module and various electronic components on the circuit board. <Motor 1 Overview> Fig. 1 is a cross-sectional view taken along the direction of the rotation axis of motor 1, and shows a schematic cross-sectional structure of motor 1. Fig. 2 is a cross-sectional view taken perpendicular to the rotation axis of motor 1, and shows a schematic cross-sectional structure of motor 1. The motor 1 has an inverter-driven motor body 1a and an inverter module 100 that controls the motor body 1a. In this embodiment, the inverter module 100 is attached to the upper portion of the motor body 1a in the figure.

[0010] <Motor body 1a> The motor body 1a includes a motor housing 12, and a rotor 2 and a stator 4 housed inside the motor housing 12. A shaft 3 is attached to the center of the rotor 2 as an output shaft (i.e., a rotating shaft), and is rotatably supported by two bearings 3a on the left and right.

[0011] The motor housing 12 has a cylindrical portion 12a and two side plate portions 12b provided to close openings on both sides of the cylindrical portion 12a. The motor housing 12 (cylindrical portion 12a, side plate portions 12b) is made of, for example, resin.

[0012] The cylindrical portion 12a is provided with a connection structure 25 for connecting to the inverter module 100. In the connection structure 25, the bus bar 30 of the inverter module 100 and a coil terminal 26 extending from the coil 9 are connected.

[0013] Each side plate portion 12b is provided in a substantially disk shape and closes the end openings at both axial ends (both left and right ends in FIG. 1) of the cylindrical portion 12a, which has a cylindrical shape. A bearing 3a is provided at the center of each side plate portion 12b and rotatably supports the shaft 13.

[0014] The rotor 2 has a roughly cylindrical shape and is made by laminating multiple disk-shaped electromagnetic steel plates. A shaft 3 is attached to the center of the rotor 2 so that it passes through in the axial direction. Additionally, multiple rectangular parallelepiped permanent magnets 5 are arranged near the outer periphery of the rotor 2 so that they are equally spaced in the circumferential direction.

[0015] The stator 4 is substantially cylindrical and is disposed and fixed on the inner periphery of the motor housing 12 (more specifically, the cylindrical portion 12a) so as to surround the outer periphery of the rotor 2. A minute gap (air gap) is provided between the inner periphery of the stator 4 and the outer periphery of the rotor 2.

[0016] The stator 4 is made by laminating multiple thin magnetic steel sheets. The stator 4 has a cylindrical yoke 6 and multiple teeth 7 arranged from the yoke 6 toward the rotor 2. A space called a slot 8 is provided between each tooth 7.

[0017] Coils 9 are housed in the slots 8. The coils 9 are either distributed or concentrated windings. The slots 8 are filled with a highly thermally conductive resin that fills the gaps along with the coils 9. The coils 9 and the stator 4 are tightly packed with resin material, which allows for smooth heat transfer. This improves the cooling performance of the stator 4 and reduces copper loss (loss consumed by the resistance of the coils 9 themselves), thereby improving motor output and enabling the motor 1 to be made more compact.

[0018] <Inverter module 100> The inverter module 100 includes a power module 101 that converts AC current to DC current, a smoothing capacitor 130, a bus bar module 10 that connects the power module 101 to the motor main body 1a (more specifically, the coil 9 of the stator 4), and a bus bar module 10a that connects a semiconductor element (power semiconductor) 120 to the smoothing capacitor 130, all of which are housed in a housing 110. The smoothing capacitor 130 may be, for example, an electrolytic capacitor. Although the smoothing capacitor 130 has been exemplified as a smoothing module that smooths the current, any configuration other than a capacitor may be used as long as it is capable of smoothing the current.

[0019] The inverter module 100 has an inverter cooling channel 102 for cooling the power module 101 and a bus bar cooling channel 45 for cooling the bus bar module 10.

[0020] <Power Module 101> The power module 101 includes a plurality of semiconductor elements (power semiconductors) 120, a metal heat dissipation member attached to the underside of the semiconductor elements 120, and a lead frame connected to the semiconductor elements, and is sealed with resin. The lead frame protrudes and is exposed from the sealing resin and is directly or indirectly connected to the bus bar modules 10, 10a. That is, the power module 101 obtains smoothed direct current from the smoothing capacitor 130 via the bus bar module 10a, converts it into alternating current, and supplies the alternating current to the motor main body 1a via the bus bar module 10. In other words, the bus bar module 10 is provided in the AC path. The bus bar module 10a is provided in the DC path 61. The bus bar module 10 connected to the motor main body 1a and the bus bar module 10a connected to the smoothing capacitor 130 have the same basic structure, and the bus bar module 10 connected to the motor main body 1a will be described below.

[0021] <Inverter cooling channel 102> The inverter cooling flow path 102 is provided on the underside of the power module 101, and a refrigerant (cooling water) flows through it to cool the power module 101. Here, heat dissipation fins provided on the underside of the power module 101 are exposed inside the inverter cooling flow path 102 and come into contact with the refrigerant.

[0022] The inverter cooling flow path 102 and the bus bar cooling flow path 45 described later in FIG. 4 may be configured to have a common configuration in which the inverter cooling flow path 102 and the bus bar cooling flow path 45 are directly connected, or may be configured such that a part of the inverter cooling flow path 102 branches off midway and then merges again, or may be configured such that the same cooling water circulates through the different flow paths.

[0023] <Busbar module 10> Fig. 3 is a plan view of the bus bar module 10. Fig. 4 is a cross-sectional view of the bus bar module 10, where Fig. 4(a) is a cross-sectional view taken along X1-X1 in Fig. 3, Fig. 4(b) is a cross-sectional view taken along X2-X2 in Fig. 3, and Fig. 4(c) is a cross-sectional view taken along X3-X3 in Fig. 3.

[0024] The bus bar module 10 includes a bus bar 30, a bus bar sealing portion 40 that seals a part of the bus bar 30 with resin, a current sensor 20, and a bus bar cooling channel 45.

[0025] <Busbar 30> In this embodiment, the bus bars 30 include a first bus bar 31, a second bus bar 32, and a third bus bar 33 arranged in parallel. When the first bus bar 31, the second bus bar 32, and the third bus bar 33 are not distinguished from one another, they will be simply referred to as "bus bars 30." The bus bars 30 are formed into a plate shape from a conductive metal (including alloys) such as copper or aluminum. The bus bars 30 may be bent as necessary depending on the mounting position, the position of the portion (opening) extending to the outside, and other factors. In this embodiment, the bus bars 30 are bent at the end of the bus bar sealing portion 40 (the upper end in FIG. 4(a)) toward the motor main body 1a, and the end extending a predetermined length is connected to the coil terminal 26.

[0026] In this embodiment, the length of the bus bars 30 is such that the first bus bar 31 is the longest and the third bus bar 33 is the shortest, but this is not intended to be limited to this and the bus bars may be the same length, and the length may be set appropriately depending on the positional relationship with the component to be connected, etc.

[0027] The width of bus bar 30 is set appropriately depending on the specifications of motor 1, but can be, for example, 5 mm to 30 mm. The thickness of bus bar 30 is set appropriately depending on the specifications of motor 1, but can be, for example, 0.5 mm to 5.0 mm. As long as the desired performance of motor 1 can be achieved, the widths and thicknesses of first bus bar 31, second bus bar 32, and third bus bar 33 may be the same or different.

[0028] The busbar 30 has through holes 36 formed in its thickness direction at predetermined positions (in FIG. 4 , near the lower end and near the upper bend position). The through holes 36 are aligned with the through holes formed in the busbar sealing portion 40. The through holes 36 are used for fastening to other components, etc. The through holes 36 are also used as a positioning means in a mold (inside a cavity) used when sealing the busbar sealing portion 40 to the busbar 30 by insert molding. That is, the through holes 36 are fitted into protrusions formed in the cavity of the mold, and are thereby positioned appropriately inside the cavity.

[0029] <Busbar sealing portion 40> Busbar sealing portion 40 has a structure in which at least a portion of busbar 30 is sealed with a cured resin product formed by curing a thermosetting resin. In the present embodiment, as an example, the central portion of busbar 30 in the longitudinal direction is sealed with busbar sealing portion 40. Here, first busbar 31, second busbar 32, and third busbar 33 are commonly sealed with busbar sealing portion 40. The upper surface portions of both end portions of busbar 31, second busbar 32, and third busbar 33 are not sealed and are exposed.

[0030] Additionally, the current sensor 20 is disposed on the upper surface of the bus bar 30 in the area where the bus bar sealing portion 40 seals the bus bar 30. In other words, the current sensor 20 is sealed together with the bus bar 30 by the bus bar sealing portion 40. The material of the bus bar sealing portion 40 will be described later, but by using a highly thermally conductive resin and embedding a portion of the bus bar 30 in the bus bar sealing portion 40, high heat dissipation, insulation, and ease of handling can be achieved.

[0031] In the bus bar sealing portion 40, a bus bar cooling channel 45 through which a coolant (cooling water) for cooling the bus bar 30 flows is formed along the bus bar 30. The bus bar cooling channel 45 will be described in detail later.

[0032] <Current sensor 20> The current sensor 20 is a Hall element coreless type current sensor. The current sensor 20 has a sensor substrate 21, a magnetic sensor 22 having a Hall element mounted on the sensor substrate 21, and an ASIC (Application Specific Integrated Circuit) 23. In the current sensor 20, the generated magnetic field is extracted as a voltage by the Hall element 22, which is amplified and corrected by the ASIC 23 and output to the outside from a connection terminal 24. The Hall element coreless type current sensor can be made smaller and thinner than the Hall type current sensor. In this embodiment, current sensor 20 is in a packaged form in which magnetic sensors 22 (Hall elements) are provided on first bus bar 31, second bus bar 32, and third bus bar 33, and the magnetic sensors 22 are amplified and corrected by one ASIC 23, but this is not limiting and current sensor 20 may be configured as a sensor consisting of one magnetic sensor 22 (Hall element) and one ASIC 23. If there is no demand for miniaturization, a Hall-type current sensor may be used as current sensor 20.

[0033] <Busbar cooling channel 45> The busbar cooling channels 45 are provided as through-holes in the busbar sealing portion 40 so as to extend along the busbars 30, and a coolant such as cooling water flows through them. Here, as shown in FIG. 4(c), the busbar cooling channels 45 are provided below the first busbar 31, the second busbar 32, and the third busbar 33 (on the motor body 1a side), in a position between the first busbar 31 and the second busbar 32 and a position between the second busbar 32 and the third busbar 33, in the longitudinal direction of the busbars 30. Both ends of the busbar cooling channels 45 are connected to the inverter cooling channels 102, and the same coolant (cooling water) circulates in the busbar cooling channels 45 as in the inverter cooling channels 102.

[0034] The busbar cooling flow passage 45 may be provided directly in the busbar sealing portion 40 (i.e., the flow passage wall surface may be part of the busbar sealing portion 40), or a separate tube member may be embedded therein. By forming the busbar sealing portion 40 from a highly thermally conductive resin, heat can be conducted effectively from the busbar 30 to the busbar cooling flow passage 45.

[0035] <Physical properties of bus bar sealing portion 40> The physical properties of the cured resin material that forms the bus bar sealing portion 40 are as follows, for example. The thermal conductivity of the cured resin material is, for example, 1 W / mK or more. The lower limit of the thermal conductivity is preferably 2 W / mK or more, and more preferably 3 W / mK or more. The upper limit of the thermal conductivity is not particularly limited, but a practical value is 5 W / mK or less.

[0036] The glass transition temperature Tg of the resin composition of bus bar sealing portion 40 is, for example, 120° C. or higher, preferably 140° C. or higher, and more preferably 160° C. or higher. By setting the glass transition temperature Tg within the above range, motor 1 can be used at high temperatures and can be resistant to heat generation in coil 9, allowing it to be used at high output.

[0037] The linear expansion coefficient of the cured resin material of the busbar sealing portion 40 at a temperature equal to or lower than the glass transition temperature is, for example, 50 ppm / K or less. The linear expansion coefficient is preferably 40 ppm / K or less, and more preferably 30 ppm / K or less. The lower limit of the linear expansion coefficient is, for example, 1010 ppm / K or more, and preferably 15 ppm / K. Setting the linear expansion coefficient in this range reduces the difference in the linear expansion coefficient with the busbar 30, and can suppress changes in the bonding state between the busbar sealing portion 40 and the busbar 30 due to the influence of heat (such as a decrease in bonding strength or separation). In other words, a decrease in thermal conductivity between the busbar sealing portion 40 and the busbar 30 can be prevented.

[0038] <Material of Bus Bar Sealing Portion 40> The material of the bus bar sealing portion 40 is preferably a thermosetting resin. By using a thermosetting resin, the pressure required when molding the bus bar sealing portion 40 can be reduced. For example, a thermoplastic resin requires a molding pressure of about 30 MPa, but by using a thermosetting resin, the molding pressure can be reduced to about 7 to 20 MPa. When molding the bus bar sealing portion 40 while encapsulating the current sensor 20, as in this embodiment, the impact on the current sensor 20 can be reduced.

[0039] The resin composition of the bus bar sealing portion 40 preferably contains a thermosetting resin (A), a filler (B), a curing agent (C), and the like.

[0040] [Thermosetting resin (A)] Examples of the thermosetting resin (A) include epoxy resins, cyanate resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, bismaleimide resins, phenoxy resins, and acrylic resins. As the thermosetting resin (A), one of these may be used alone, or two or more may be used in combination. Among these, from the viewpoint of high insulating properties, it is preferable that the thermosetting resin (A) contains an epoxy resin or a phenol resin.

[0041] Examples of epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisopridiene)bisphenol type epoxy resin), and bisphenol Z type epoxy resin (4,4'-cyclohexidienebisphenol type epoxy resin); phenol novolac type epoxy resin, cresol novolac type epoxy resin, trisphenol methane type novolac type epoxy resin, tetraphenol group ethoxylated epoxy resin, and the like. Examples of epoxy resins include novolac-type epoxy resins such as benzophenone-type novolac-type epoxy resins and novolac-type epoxy resins having a condensed ring aromatic hydrocarbon structure; biphenyl-type epoxy resins; aryl alkylene-type epoxy resins such as xylylene-type epoxy resins and biphenyl aralkyl-type epoxy resins; naphthalene-type epoxy resins such as naphthylene ether-type epoxy resins, naphthol-type epoxy resins, naphthalene diol-type epoxy resins, bifunctional to tetrafunctional epoxy-type naphthalene resins, binaphthyl-type epoxy resins, and naphthalene aralkyl-type epoxy resins; anthracene-type epoxy resins; phenoxy-type epoxy resins; dicyclopentadiene-type epoxy resins; norbornene-type epoxy resins; adamantane-type epoxy resins; and fluorene-type epoxy resins. These may be used alone or in combination of two or more.

[0042] Among the epoxy resins, from the viewpoint of further improving heat resistance and insulation reliability, it is preferable to use one or more types selected from the group consisting of bisphenol-type epoxy resins, novolac-type epoxy resins, biphenyl-type epoxy resins, aryl alkylene-type epoxy resins, naphthalene-type epoxy resins, anthracene-type epoxy resins, and dicyclopentadiene-type epoxy resins.

[0043] Examples of phenolic resins include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, and bisphenol A novolac resin, and resol-type phenolic resins, etc. One of these may be used alone, or two or more may be used in combination. Among the phenolic resins, phenolic novolac resins are preferred.

[0044] The content of the thermosetting resin (A) is preferably 1% by mass or more, and more preferably 5% by mass or more, relative to the total amount of the resin composition of the bus bar sealing portion 40. On the other hand, the content is preferably 30% by mass or less, and more preferably 20% by mass or less, relative to the total amount of the resin composition of the bus bar sealing portion 40. When the content of the thermosetting resin (A) is equal to or greater than the above lower limit, the handleability of the entire resin composition of the bus bar sealed portion 40 improves, making it easier to form the bus bar sealed portion 40 and improving the strength of the bus bar sealed portion 40. When the content of the thermosetting resin (A) is equal to or less than the upper limit, the linear expansion coefficient and elastic modulus of the bus bar sealing portion 40 are further improved, and the thermal conductivity is further improved.

[0045] [Filler (B)] The filler (B) in this embodiment is used from the viewpoint of improving the thermal conductivity of the bus bar sealing portion 40 and obtaining strength.

[0046] As the filler (B), an inorganic filler is preferred, and a thermally conductive filler is particularly preferred. More specifically, from the viewpoint of achieving a balance between thermal conductivity and electrical insulation, examples of the filler (B) include silica, alumina, boron nitride, aluminum nitride, and silicon carbide. These may be used alone or in combination of two or more. Among these, it is preferable that the filler (B) contains alumina.

[0047] The content of the filler (B), ie, the content of the above filler, is preferably 60% by mass or more based on the total amount of the resin composition.

[0048] [Hardening agent (C)] When an epoxy resin or a phenolic resin is used as the thermosetting resin (A), the resin composition preferably further contains a curing agent (C).

[0049] As the curing agent (C), one or more selected from the curing catalyst (C-1) and the phenol-based curing agent (C-2) can be used. Examples of the curing catalyst (C-1) include organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octoate, cobalt octoate, bisacetylacetonate cobalt(II), and trisacetylacetonate cobalt(III); tertiary amines such as triethylamine, tributylamine, and 1,4-diazabicyclo[2.2.2]octane; 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2,4-diethylimidazole, and 2-phenyl-4-methyl-5-hydroxyimidazole; Examples of suitable curing catalysts include imidazoles such as 2-phenyl-4,5-dihydroxymethylimidazole; organic phosphorus compounds such as triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium tetraphenylborate, triphenylphosphine triphenylborane, and 1,2-bis-(diphenylphosphino)ethane; phenolic compounds such as phenol, bisphenol A, and nonylphenol; and organic acids such as acetic acid, benzoic acid, salicylic acid, and p-toluenesulfonic acid, or mixtures thereof. The curing catalyst (C-1) can be used alone or in combination with two or more of these, including their derivatives. The content of the curing catalyst (C-1) is not particularly limited, but is preferably 0.001% by mass or more and 1% by mass or less based on the total amount of the resin composition.

[0050] Examples of the phenolic curing agent (C-2) include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, trisphenolmethane-type novolac resin, naphthol novolac resin, and aminotriazine novolac resin; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; aralkyl-type resins such as phenol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton and naphthol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton; bisphenol compounds such as bisphenol A and bisphenol F; and resol-type phenolic resins, and these may be used alone or in combination of two or more. Among these, from the viewpoint of improving the glass transition temperature and reducing the linear expansion coefficient, the phenolic curing agent (C-2) is preferably a novolac type phenolic resin or a resol type phenolic resin.

[0051] The content of the phenolic curing agent (C-2) is not particularly limited, but is preferably 1% by mass or more, more preferably 5% by mass or more, based on the total amount of the resin composition, and is preferably 30% by mass or less, more preferably 15% by mass or less, based on the total amount of the resin composition.

[0052] [Coupling agent (D)] The resin composition may contain a coupling agent (D), which can improve the wettability at the interface between the thermosetting resin (A) and the filler (B).

[0053] The coupling agent (D) is not particularly limited, but it is preferable to use one or more coupling agents selected from, for example, epoxy silane coupling agents, cationic silane coupling agents, amino silane coupling agents, titanate-based coupling agents, and silicone oil-type coupling agents. The content of the coupling agent (D) is not particularly limited, but is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, relative to 100% by mass of the filler (B), and is preferably 3% by mass or less, more preferably 2% by mass or less, relative to 100% by mass of the filler (B).

[0054] [Phenoxy resin (E)] Furthermore, the resin composition may contain a phenoxy resin (E). By containing the phenoxy resin (E), the bending resistance of the bus bar sealed portion 40 can be improved, and the elastic modulus can be reduced, thereby improving the stress relaxation force of the bus bar sealed portion 40.

[0055] Furthermore, when the phenoxy resin (E) is contained, the viscosity increases, which reduces the flowability and prevents the occurrence of voids, etc. Furthermore, when the busbar sealing portion 40 is used in close contact with a metal member (i.e., tooth 7), the adhesion between the metal and the cured resin composition can be improved.

[0056] Examples of the phenoxy resin (E) include phenoxy resins having a bisphenol skeleton, phenoxy resins having a naphthalene skeleton, phenoxy resins having an anthracene skeleton, and phenoxy resins having a biphenyl skeleton. Phenoxy resins having a structure having multiple types of these skeletons can also be used.

[0057] The content of the phenoxy resin (E) is preferably, for example, 3% by mass or more and 10% by mass or less relative to the total amount of the resin composition.

[0058] [Release agent] The resin composition preferably contains a mold release agent, which can improve mold releasability after molding. Examples of mold release agents include natural waxes such as carnauba wax, synthetic waxes such as Montan acid ester wax and oxidized polyethylene wax, higher fatty acids such as zinc stearate and their metal salts, and paraffin. These may be used alone or in combination of two or more.

[0059] When a mold release agent is used, its content in the entire resin molding material is preferably 0.01 to 3 mass %, more preferably 0.05 to 2 mass %. This ensures improved mold releasability. As a result, the molding precision of the bus bar sealing portion 40 can be improved.

[0060] [Other ingredients] The resin composition may also contain other additives such as an antioxidant and a leveling agent, provided that the effects of the present invention are not impaired.

[0061] <Method for manufacturing busbar module 10> 5 is a flowchart showing a method for manufacturing the bus bar module 10. The bus bar module 10 is manufactured by transfer molding or compression molding.

[0062] Preparation process S10: First, in a preparation step, a thermosetting resin that will be the material for the bus bar 30, the current sensor 20, and the bus bar sealing portion 40 is prepared.

[0063] Busbar sealing process S20: The busbar sealing process S20 includes a component placement process S21 in which components are placed inside the cavity of the mold, a resin injection process S22 in which a resin material (thermosetting resin) is injected into the cavity, and a removal process S23 in which the molded busbar module 10 is removed.

[0064] In the component placement process S21, the through holes 36 of the bus bars 30 are fitted into protrusions, which are positioning means provided inside the cavity of the mold, and the bus bars 30 (first bus bar 31, second bus bar 32, third bus bar 33) are placed in predetermined positions. Next, the current sensor 20 is placed on the bus bars 30. Other sealing components are placed as necessary.

[0065] In the resin filling step S22, the cavity of the mold is filled with a resin material by transfer molding or compression molding. Using the aforementioned thermosetting resin (particularly epoxy resin) as the resin material allows the molding pressure to be kept below 20 MPa. As a result, adverse effects on components such as the current sensor 20 contained within the bus bar sealing portion 40 can be suppressed. If the current sensor 20 is a Hall element coreless current sensor, the types of sensors that can be used may be limited if the molding pressure exceeds 20 MPa. However, keeping the molding pressure below 20 MPa broadens the types of sensors that can be used, improving design flexibility.

[0066] The features of this embodiment can be briefly summarized as follows. (1) a bus bar 30 made of a conductive metal and electrically connected to a power module 101 having a plurality of semiconductor elements and performing current conversion between direct current and alternating current; a busbar sealing portion (40) in which at least a portion of the busbar (30) is sealed with a cured resin product obtained by curing a thermosetting resin; A structure (busbar module 10) having the above structure. (2) The structure (busbar module 10) according to (1), wherein the thermosetting resin includes an epoxy resin or a phenolic resin. (3) The structure (busbar module 10) according to (1) or (2), wherein the cured resin has a thermal conductivity of 1 W / mK or more and 5 W / mK or less. (4) The structure (busbar module 10) according to any one of (1) to (3), wherein the linear expansion coefficient of the cured resin at a temperature equal to or lower than the glass transition temperature is 50 ppm / K or less. (5) A current sensor 20 is provided to detect a current flowing through the bus bar 30. The structure (busbar module 10) according to any one of (1) to (4), wherein the current sensor 20 is sealed in the cured resin. (6) The structure (busbar module 10) according to (5), wherein the current sensor 20 is a Hall element coreless current sensor. (7) The structure (busbar module 10 ) according to any one of (1) to (6), wherein the busbar sealing portion 40 has a busbar cooling passage 45 that cools the busbar 30 . (8) The structure (busbar module 10) is provided in an AC path through which AC current flows between the power module 101 and the stator 4 of a rotating electric machine (motor 1), the structure (busbar module 10) being described in any one of (1) to (7). (9) The structure (busbar module 10) is provided in a DC path through which a DC current flows between the power module 101 and a smoothing module (smoothing capacitor 130), the structure (busbar module 10) being described in any one of (1) to (7). (10) a power module 101 having a plurality of semiconductor elements and performing power conversion between DC and AC; a DC path connected to the power module 101 through which a DC current flows; a smoothing module (smoothing capacitor 130) provided in the DC path for smoothing the DC current; an AC path connected to the power module 101 through which an AC current flows, An inverter module 100 in which a rotating electric machine (motor body 1a) is connected to the AC path, An inverter module 100 having a structure (busbar module 10) described in any one of (1) to (9) between the power module 101 and the smoothing module (smoothing capacitor 130) in the DC path or in the AC path. (11) an inverter cooling flow path 102 for cooling the inverter module 100; a bus bar cooling channel 45 for cooling the bus bar 30 of the structure (bus bar module 10), The inverter module 100 according to (12), wherein the inverter cooling channel 102 and the bus bar cooling channel 45 are configured in common. (12) A motor (1) comprising an inverter module (100) of (10) or (11) and a motor body (1a) to which power is supplied from the inverter module (100). (13) A method for manufacturing the structure (inverter module 100) according to any one of (1) to (9), a bus bar sealing step of sealing at least a portion of the bus bar (30) made of conductive metal with a thermosetting resin; The manufacturing method, wherein the bus bar sealing step is performed by compression molding or transfer molding. (14) The bus bar sealing step is performed by compression molding, The bus bar 30 has a through hole 36 penetrating near an end thereof, The manufacturing method according to (13), wherein a positioning protrusion for fitting the through hole 36 of the bus bar 30 is provided inside the mold used for the compression molding. (15) The manufacturing method according to (14), wherein the molding pressure in the compression molding in the bus bar sealing step is 20 MPa or less. (16) The method according to any one of (13) to (15), wherein the thermosetting resin includes an epoxy resin or a phenolic resin.

[0067] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted.

[0068] This application claims priority based on Japanese Patent Application No. 2023-187431, filed November 1, 2023, the disclosure of which is incorporated herein by reference in its entirety. [Explanation of symbols]

[0069] 1 motor 1a Motor body 2 rotors 4 Stator 5. Permanent magnets 6 York 7 Teeth 8 slots 9 coils 10 Busbar Module 20 Current Sensor 30 Busbar 31 First bus bar 32 Second bus bar 33 3rd bus bar 36 Through hole 40 Busbar sealing part 45 Busbar cooling channels 100 Inverter Module 100a motor body 101 Power Module 110 Inverter housing 120 Semiconductor elements 130 Smoothing capacitor (smoothing module)

Claims

1. a bus bar made of a conductive metal and electrically connected to a power module having a plurality of semiconductor elements and performing current conversion between direct current and alternating current; a bus bar sealing portion in which at least a portion of the bus bar is sealed with a cured resin product obtained by curing a thermosetting resin; and the linear expansion coefficient of the cured resin at a temperature equal to or lower than the glass transition temperature is 50 ppm / K or less; the resin composition constituting the bus bar sealing portion contains the thermosetting resin and a filler, and the filler is a thermally conductive filler; The structure, wherein the content of the thermally conductive filler in the resin composition is 60 mass% or more with respect to the total amount of the resin composition.

2. 10. The structure of claim 1, wherein the thermosetting resin comprises an epoxy resin or a phenolic resin.

3. The structure according to claim 1 or 2, wherein the cured resin has a thermal conductivity of 1 W / mK or more and 5 W / mK or less.

4. a current sensor for detecting a current flowing through the bus bar; The structure according to claim 1 or 2, wherein the current sensor is sealed in the cured resin.

5. The structure of claim 4 , wherein the current sensor is a Hall element coreless current sensor.

6. The structure according to claim 1 or 2, wherein the bus bar sealing portion has a bus bar cooling channel for cooling the bus bar.

7. The structure according to claim 1 or 2, wherein the structure is provided in an AC path through which an AC current flows between the power module and a stator of a rotating electrical machine.

8. The structure according to claim 1 or 2, wherein the structure is provided on a DC path through which a DC current flows between the power module and the smoothing module.

9. a power module having a plurality of semiconductor elements for converting power between direct current and alternating current; a DC path connected to the power module through which a DC current flows; a smoothing module provided in the DC path for smoothing the DC current; an AC path connected to the power module through which an AC current flows, An inverter module in which a rotating electric machine is connected to the AC path, An inverter module comprising the structure according to claim 1 or 2 between the power module and the smoothing module in the DC path or in the AC path.

10. an inverter cooling flow path that cools the inverter module; a bus bar cooling channel for cooling the bus bar of the structure, The inverter module according to claim 9 , wherein the inverter cooling passage and the bus bar cooling passage are formed in common.

11. A motor comprising: the inverter module according to claim 9; and a motor body to which power is supplied from the inverter module.

12. A method for manufacturing the structure according to claim 1, comprising: a bus bar sealing step of sealing at least a portion of a bus bar made of a conductive metal with a thermosetting resin; The manufacturing method, wherein the bus bar sealing step is performed by compression molding or transfer molding.

13. The bus bar sealing step is performed by compression molding, the bus bar has a through hole penetrating near an end portion, The manufacturing method according to claim 12 , wherein a positioning protrusion for receiving the through hole of the bus bar is provided inside a mold used for the compression molding.

14. The manufacturing method according to claim 13 , wherein a molding pressure in the compression molding in the bus bar sealing step is 20 MPa or less.

15. The method of claim 12 , wherein the thermosetting resin comprises an epoxy resin or a phenolic resin.

16. A structure described in claim 1 or 2, wherein the thermally conductive filler comprises one or more selected from the group consisting of silica, alumina, boron nitride, aluminum nitride, and silicon carbide.

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