unit

Abstract

[Problem] To provide a structure that reflects a mode of utilization of a fibrous body based on the technological concept of performing cooling by utilizing a turbulence effect. [Solution] This unit comprises a coolant fluid, an electric circuit unit, and a heat-conducting fibrous body. The heat-conducting fibrous body comprises a contact portion in contact with the electric circuit unit, and a folded portion which is folded. The folded portion is disposed in the fluid flow path of the coolant fluid.

Description

[Technical Field]

[0001] The present invention relates to a unit. [Background technology]

[0002] Patent Document 1 discloses a cooling element in which a metal fiber sheet is housed in a housing that contacts a heat generating element, and heat conducted from the heat generating element to the metal fiber sheet is removed by a refrigerant introduced into the housing. The metal fiber sheet is made of copper or aluminum fibers with high thermal conductivity, and is therefore efficiently cooled by the refrigerant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-9433 Summary of the Invention [Problem to be solved by the invention]

[0004] As a result of extensive research, the inventors have found that when a coolant passes through a fiber, turbulence occurs, and the turbulence effect promotes cooling. Furthermore, they have found that when a coolant passes over the surface of a fiber, turbulence occurs due to disturbances on the fiber surface, and the turbulence effect also promotes cooling.

[0005] This means that cooling performance can be improved regardless of the material of the fiber body, and that the fiber body can be used for cooling with a technical idea that is completely different from the technical idea described in Patent Document 1, that is, cooling that utilizes the thermal conductivity of a metal fiber sheet. For this reason, it is desirable to provide a unit with a new structure that reflects the use of a fiber body based on the technical idea of cooling that utilizes the turbulent effect.

[0006] The present invention has been made in consideration of these problems, and aims to provide a structure that reflects the utilization of a fibrous body based on the technical idea of utilizing the turbulent effect for cooling. [Means for solving the problem]

[0007] The unit according to one aspect of the present invention includes a coolant, an electric circuit unit, and a heat-conducting fiber, the heat-conducting fiber having a contact portion that contacts the electric circuit unit and a bent portion that is disposed within the flow path of the coolant. [Effects of the Invention]

[0008] According to this aspect, arranging the bent portion in the liquid flow path generates turbulence, thereby promoting cooling of the bent portion itself. Furthermore, the bent portion is thermally connected to the electric circuit unit via the contact portion. Therefore, by dissipating heat from the electric circuit unit into the coolant via the bent portion, the electric circuit unit can be cooled using the turbulent effect, thereby improving the cooling efficiency of the electric circuit unit. Furthermore, because the length and flexibility of this heat-conducting fiber structure can be adjusted as needed, this means that the cooling flow path can be formed anywhere, contributing to increased layout flexibility for the entire unit. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of the unit according to this embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a main part of the inverter. [Figure 3] FIG. 3 is an enlarged cross-sectional view showing the bent portion together with the partial passage. [Figure 4] FIG. 4 is an explanatory diagram of the bending direction of the bending portion. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0011] FIG. 1 is a schematic diagram of a unit 100 according to this embodiment. FIG. 2 is a cross-sectional view showing a main part of the inverter 10. FIG. 3 is a cross-sectional view showing an enlarged view of the bent portion 13b together with the partial passage 53a. FIG. 4 is a view illustrating the bending direction of the bent portion 13b with respect to the liquid flow direction F in the AA cross section shown in FIG. 3. In FIG. 1, the rotor and stator of the rotating electric machine 20 and the reduction gear mechanism of the reduction gear 30 are not shown for the rotating electric machine 20 and the reduction gear 30, and the oil reservoir 21b of the rotating electric machine 20 and the oil reservoir 31b of the reduction gear 30 are shown in cross section.

[0012] The unit 100 is mounted on, for example, an electric vehicle using a rotating electric machine 20 as a drive source. The unit 100 has an inverter 10, a rotating electric machine 20, a reducer 30, and a cooling device 50. The inverter 10 is an electric circuit unit and has a case 11 and an electric circuit 12. The case 11 is a housing and houses the electric circuit 12. The case 11 is made of, for example, an aluminum alloy. The case 11 may have a portion made of, for example, resin. The case 11 has a box-shaped portion 111 and a plate-shaped portion 112. The box-shaped portion 111 has a box-like shape with one side open, and the plate-shaped portion 112 closes the opening of the box-shaped portion 111. The case 11 is arranged so that the plate-shaped portion 112 forms the lower surface in the direction of gravity.

[0013] The electric circuit 12 is provided inside the case 11. The electric circuit 12 has a board 121 and a circuit section 122. In FIG. 2, the circuit section 122 is shown surrounded by a two-dot dashed line. The board 121 is a printed circuit board, and is disposed on the bottom wall of the case 11. The circuit section 122 is mounted on the board 121. The circuit section 122 is electrically connected to the board 121 by connecting to the circuit pattern of the board 121.

[0014] The circuit section 122 has a semiconductor element 122a, wires 122b, a lead frame 122c, a bonding member 122d, a heat dissipation member 122e, and a mold resin 122f. The semiconductor element 122a is, for example, a power element, such as an IGBT or a power MOSFET, or other switching element. A plurality of semiconductor elements 122a can be provided, and they can be arranged, for example, in the depth-to-front direction of FIG. 2 (a direction perpendicular to the paper surface of FIG. 2). The semiconductor element 122a is electrically connected to the lead frame 122c via the wires 122b.

[0015] The bonding member 122d bonds the semiconductor element 122a and the heat dissipation member 122e, and the heat dissipation member 122e is used to dissipate heat from the semiconductor element 122a. Both the bonding member 122d and the heat dissipation member 122e are heat-conducting members, and heat from the semiconductor element 122a is conducted to the heat dissipation member 122e via the bonding member 122d. The bonding member 122d and the heat dissipation member 122e are members having a higher thermal conductivity than, for example, the mold resin 122f.

[0016] The semiconductor element 122a is provided in and sealed with mold resin 122f. Heat dissipation from the semiconductor element 122a is performed, for example, via mold resin 122f. Meanwhile, the lead frame 122c protrudes from the mold resin 122f, and the heat dissipation member 122e is exposed from the mold resin 122f. Therefore, heat dissipation from the semiconductor element 122a can also be promoted via the lead frame 122c and the heat dissipation member 122e. The lead frame 122c and the heat dissipation member 122e together constitute a heat dissipation promoting portion that promotes heat dissipation from the semiconductor element 122a to the outside of the mold resin 122f.

[0017] The rotating electric machine 20 is controlled by the inverter 10 and generates power. The power generated by the rotating electric machine 20 is transmitted to the drive wheels of the vehicle via the reducer 30. The rotating electric machine 20 has a case 21. The case 21 has an inlet 21a and an oil reservoir 21b, and houses the rotor and stator of the rotating electric machine 20. The inverter 10 is mounted on the case 21 from the outside. The inverter 10 is mounted on the case 21 from the side.

[0018] Inlet port 21a penetrates the top wall of case 21, connecting the inside and outside of case 21. Oil OL, which is a coolant, is introduced into case 21 through inlet port 21a. The introduced oil OL falls due to gravity, lubricating the rotor and cooling the stator, and then is stored in oil reservoir 21b. A part of the stator can be placed in oil reservoir 21b, which allows the oil OL stored in oil reservoir 21b to be used to cool the stator.

[0019] The reducer 30 reduces the input rotation from the rotating electric machine 20 and outputs the reduced rotation. The reducer 30 has a case 31. The case 31 has an outlet 31a and an oil reservoir 31b, and houses a reduction gear mechanism. The case 31 is integrated with the case 21 by, for example, bolting, and together with the case 21, constitutes a housing 40 for the rotating electric machine 20 and the reducer 30.

[0020] The housing 40 has a communication port 41, which communicates between the oil reservoir 21b in the case 21 and the oil reservoir 31b in the case 31. Therefore, the oil OL can be introduced from the oil reservoir 21b to the oil reservoir 31b through the communication port 41. The wall in which the communication port 41 is provided is formed of, for example, a part of the case 21.

[0021] The oil reservoir 31b stores the oil OL introduced from the oil reservoir 21b. The oil OL stored in the oil reservoir 31b is scooped up by rotating members such as gears and used to lubricate the reduction gear mechanism. The oil OL is discharged from the oil reservoir 31b through the discharge port 31a from the inside of the case 31. The reducer 30 corresponds to a power transmission mechanism.

[0022] The cooling device 50 has an oil pump 51, an oil cooler 52, and a connecting passage 53. The oil pump 51 has an intake port 51a and a discharge port 51b, and pumps out oil OL. The discharge port 51b is connected to the oil cooler 52, and the oil cooler 52 cools the oil OL pumped out by the oil pump 51.

[0023] The connecting passage 53 branches from the discharge port 51b of the oil pump 51 via the oil cooler 52 to connect to the inverter 10 and the rotating electrical machine 20. One end of the branched connecting passage 53 is connected to the inlet 21a of the rotating electrical machine 20. The other end of the branched connecting passage 53 is connected to one end of the partial passage 53a.

[0024] The partial passage 53a is a connecting passage 53 provided in the case 11, and has both ends that penetrate the case 11. One end of the partial passage 53a penetrates the case 11 on the front side in Figures 1 and 2, and the other end penetrates the case 11 on the back side in Figures 1 and 2. The connecting passage 53 further merges the other end of the partial passage 53a with the discharge port 31a of the reducer 30, and then connects to the suction port 51a of the oil pump 51.

[0025] As a result, a first circulation path C1 and a second circulation path C2 are formed in the unit 100. The first circulation path C1 is a circulation path through which the oil OL passes from the oil pump 51 through the oil cooler 52 and the inverter 10 in this order, and returns to the oil pump 51. The second circulation path C2 is a circulation path through which the oil OL passes from the oil pump 51 through the oil cooler 52, the rotating electrical machine 20, and the reducer 30 in this order, and returns to the oil pump 51. The first circulation path C1 corresponds to a liquid flow path, and the oil OL flows through the partial passage 53a using the oil pump 51 incorporated in the first circulation path C1 as a coolant supply source.

[0026] As shown in FIG. 2, the inverter 10 further includes a fibrous body 13. The fibrous body 13 is a heat-conductive fibrous body made of a heat-conductive material such as metal including an alloy or carbon. The fibrous body 13 is a heat-conductive fibrous body made of a material with a higher thermal conductivity than the mold resin 122f, for example. The fibrous body 13 is provided inside the case 11 and has an elongated plate-like or strip-like shape. The fibrous body 13 has a contact portion 13a and a bent portion 13b.

[0027] The contact portion 13a is provided at one end of the fibrous body 13 and is in contact with the heat dissipation member 122e. The contact portion 13a is disposed between the heat dissipation member 122e and the substrate 121 and is in surface contact with the surface of the heat dissipation member 122e through its plate-like or strip-like shape. The contact portion 13a and the heat dissipation member 122e can be joined by, for example, beam welding or ultrasonic welding. The contact portion 13a is in contact with the heat dissipation member 122e, thereby being thermally connected to the semiconductor element 122a.

[0028] The bent portion 13b is provided at the other end of the fibrous body 13. The bent portion 13b is formed by the bent portion of the fibrous body 13 and is provided separately from the contact portion 13a. The bent portion 13b is disposed within the partial passage 53a, and is thereby disposed within the first circulation path C1, i.e., within the flow (liquid flow) of the oil OL in the first circulation path C1.

[0029] When the oil OL flows over the surface of the bent portion 13b, turbulence occurs. As a result, cooling of the bent portion 13b itself is promoted. In addition, the bent portion 13b is thermally connected to the semiconductor element 122a via the contact portion 13a. Therefore, by dissipating heat from the semiconductor element 122a to the oil OL via the bent portion 13b, the semiconductor element 122a is cooled using the turbulent effect. As a result, cooling of the semiconductor element 122a is promoted, and the cooling efficiency of the semiconductor element 122a is improved. In addition, the fibrous body 13 has a structure that allows the length and flexibility to be adjusted as appropriate. This allows for a high degree of freedom in layout, such as allowing the partial passages 53a to be formed in any location, and also contributes to improving the layout freedom of the unit 100 as a whole.

[0030] The bent portions 13b are bent at multiple locations. As a result, the surface area of the bent portions 13b in the partial passages 53a is increased compared to when they are not bent, and more turbulence is caused by the oil OL flowing along the surfaces of the bent portions 13b. As a result, cooling of the semiconductor elements 122a is further promoted. In this embodiment, the bent portions 13b are bent into a spiral shape by bending the fibrous body 13 in a rolling manner along the extension direction of the fibrous body 13. As a result, the surface area of the bent portions 13b is increased not only at the outermost portions of the spiral shape but also in the portions inside the outermost portions.

[0031] The bent portions 13b are arranged in the partial passages 53a so that the bending direction of the bent portions 13b intersects with the liquid flow direction F of the oil OL passing through the bent portions 13b. This reduces the liquid flow resistance compared to when the bending direction is parallel to the liquid flow direction F. In this embodiment, the bending direction of the bent portions 13b is approximately perpendicular to the liquid flow direction F. As a result, the liquid flow resistance is reduced as much as possible. The liquid flow direction F is the extension direction of the partial passages 53a.

[0032] The partial passages 53a can be provided along the arrangement direction of the plurality of semiconductor elements 122a (for example, the back-to-front direction in FIG. 2). Therefore, in the unit 100, by providing the fibrous body 13 for each of the plurality of semiconductor elements 122a, it is possible to improve the cooling efficiency of each of the plurality of semiconductor elements 122a.

[0033] The oil OL has insulating properties. Therefore, even if the bent portion 13b is disposed in the partial passage 53a, the oil OL itself does not significantly deteriorate the insulating state of the electric circuit 12. Furthermore, the partial passage 53a can be made of, for example, resin, which also ensures the insulation of the electric circuit 12. The insulation of the electric circuit 12 may be ensured, for example, by making part of the partial passage 53a out of resin. The connecting passage 53 other than the partial passage 53a can be made of an appropriate material such as metal.

[0034] Metallic contamination such as metal chips and powder occurs from the bearings and gears inside the rotating electric machine 20 and the reducer 30, and this metallic contamination can cause a decrease in the insulating properties of the oil OL. In response to this, the unit 100 can be provided with a filter that captures the contamination, for example, in the connecting passage 53 downstream of the reducer 30. This prevents deterioration of the insulating state of the electric circuit 12 due to metallic contamination mixed in the oil OL, even if the oil OL is shared by the inverter 10, the rotating electric machine 20, and the reducer 30.

[0035] Next, the main effects of this embodiment will be described.

[0036] (1) The unit 100 includes oil OL, an inverter 10, and a fibrous body 13. The fibrous body 13 has a contact portion 13a that contacts the semiconductor element 122a of the inverter 10, and a bent portion 13b. The bent portion 13b is disposed within the first circulation path C1 of the oil OL.

[0037] In the above, the contact portion 13a that contacts the semiconductor element 122a is in direct contact with the heat dissipation member 122e, and is therefore indirectly in contact with the semiconductor element 122a via another heat-conducting member (here, the joining member 122d and the heat dissipation member 122e). In other words, the contact of the contact portion 13a includes indirect contact via another heat-conducting member. The other heat-conducting member can be a member having a higher thermal conductivity than the mold resin 122f.

[0038] With this configuration, arranging the bent portion 13b in the first circulation path C1 generates turbulence, thereby promoting cooling of the bent portion 13b itself. Furthermore, the fibrous body 13 is a heat-conducting fibrous body, and the bent portion 13b is thermally connected to the semiconductor element 122a via the contact portion 13a. Therefore, by dissipating heat from the semiconductor element 122a to the oil OL via the bent portion 13b, the semiconductor element 122a can be cooled using the turbulent effect, thereby improving the cooling efficiency of the semiconductor element 122a.

[0039] Furthermore, the structure of the fibrous body 13 allows the length and flexibility to be adjusted as needed, meaning that the cooling flow path exemplified by the partial passage 53a can be formed in any location. This configuration therefore contributes to improving the layout flexibility of the entire unit 100. The unit 100 can improve the cooling efficiency of the inverter 10 by cooling the semiconductor element 122a.

[0040] (2) In the unit 100, the contact portion 13a contacts the semiconductor element 122a at one end of the fibrous body 13, and the bent portion 13b is bent at the other end of the fibrous body 13. With this configuration, the fibrous body 13 does not need to be longer than necessary, and the bent portion 13b is easy to form.

[0041] (3) In the unit 100, the bent portion 13b is bent at multiple locations. With this configuration, the surface area of the bent portion 13b in the partial passage 53a can be increased compared to when the bent portion 13b is not bent, and therefore more turbulence can be generated, thereby improving the cooling efficiency.

[0042] (4) In the unit 100, the bending direction of the bending portion 13b intersects with the direction of the liquid flow passing through the bending portion 13b. With this configuration, it is possible to reduce the liquid flow resistance compared to when the bending direction is parallel to the liquid flow direction F.

[0043] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0044] For example, the contact portion 13a may be configured to contact the case 11. Even in this case, the inverter 10 can be cooled by utilizing the turbulent effect by dissipating heat from the case 11 to the oil OL via the fibrous body 13. Also in this case, there is a high degree of freedom in layout, for example, the partial passage 53a does not need to be provided inside the case 11, which contributes to improving the degree of freedom in layout of the unit 100 as a whole.

[0045] The coolant does not necessarily have to be oil OL, and for example, a liquid having insulating properties other than oil OL may be used as the coolant.

[0046] The unit 100 may be configured to include at least one of the rotating electric machine 20 and the reducer 30. In this case, the unit 100 may also be referred to as, for example, a motor unit (a unit having at least a motor) or a power transmission device (a device having at least a power transmission mechanism). The motor is a rotating electric machine having an electric motor function and / or a generator function (at least one of an electric motor function and a generator function). The power transmission mechanism is, for example, a gear mechanism and / or a differential gear mechanism. A device (unit) having a motor and a power transmission mechanism is included in the concepts of both a motor unit and a power transmission device. In contrast, an electric circuit unit exemplified by the inverter 10 can be one component of the unit 100 described above, and is configured to include an electric circuit and a housing that houses the electric circuit. [Explanation of symbols]

[0047] 10 Inverter (electric circuit unit) 11 cases 12 Electrical Circuits 121 PCB 122 Circuit section 122a Semiconductor elements (part of electrical circuit units) 13 Fiber body (heat-conducting fiber body) 13a Contact part 13b Bend part 20 Rotating Electric Machine 30 Reducer 50 Cooling device 53 Connecting Passage 53a Partial passage 100 units C1 First circulation path (liquid flow path) OL oil (coolant)

Claims

1. The cooling device includes a coolant, an electric circuit unit, and a heat-conducting fiber body. The heat-conducting fiber has a contact portion that contacts the electric circuit unit and a bent portion, The bent portion is disposed within a liquid flow path of the cooling liquid. unit.

2. 2. The unit of claim 1, The contact portion contacts the electric circuit unit at one end of the heat-conducting fiber; The bending portion is bent at the other end of the heat-conducting fiber body; unit.

3. 2. The unit of claim 1, The bent portion is bent at multiple locations. unit.

4. 4. A unit according to claim 1 or 3, The bending direction of the bent portion intersects with the direction of liquid flow passing through the bent portion. unit.

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