Drive unit

Abstract

The drive device includes a base plate (2) having a first surface (3) on which a power device (1) is provided and a second surface (4) opposite the first surface (3), a plurality of heat pipes (21) each having an extension portion (31) extending from the first surface (3) toward the second surface (4), a fixed portion (41) extending in a direction different from the extension direction of the extension portion (31) and fixed to the base plate (2), and a curved portion (51) provided between the extension portion (31) and the fixed portion (41), a plurality of fins (50) into which the plurality of heat pipes (21) are inserted, and a cooling fan (60) that guides air to the plurality of heat pipes (21) and the plurality of fins (50), the fixed portion (41) having a flat shape and being arranged so that the thickness direction of the fixed portion (41) is from the first surface (3) toward the second surface (4).

Description

[Technical Field]

[0001] The present disclosure relates to a drive apparatus including a power device. [Background technology]

[0002] In the fields of machine tools and factory automation (FA), there is a demand for high-output, compact drive units that operate the machines. Drive units include power devices such as semiconductor elements and capacitors that control the current supplied to the motor. Power devices generate heat as they operate, so they are cooled by heat sinks, fans, etc.

[0003] Patent Document 1 discloses a drive device that includes a switching element for driving a motor and a heat sink on which the switching element is mounted. The heat sink removes heat from the switching element, thereby cooling the switching element. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-59759 Summary of the Invention [Problem to be solved by the invention]

[0005] When a drive unit is made smaller, the heat density increases, so a cooler with high cooling performance is required. Because the cooling performance of a heat sink depends on the size of the heat sink, the drive unit disclosed in Patent Document 1 had limited improvement in cooling performance.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to improve the cooling performance of a drive device. [Means for solving the problem]

[0007] A drive device according to the present disclosure includes: a base plate having a first surface on which a power device is provided and a second surface opposite to the first surface; a plurality of heat pipes each having an extension portion extending from the first surface toward the second surface, a fixed portion extending in a direction different from the extension direction of the extension portion and fixed to the base plate, and a bent portion provided between the extension portion and the fixed portion; a plurality of fins into which the plurality of heat pipes are inserted; and a cooling fan that guides air to the plurality of heat pipes and the plurality of fins; The direction in which the cooling fan guides the air is the ventilation direction. The fixing portion has a flat shape and is disposed so that the thickness direction of the fixing portion is a direction from the first surface to the second surface. The extension portion has a flat shape and is arranged so that the thickness direction of the extension portion does not coincide with the airflow direction. [Effects of the Invention]

[0008] According to the present disclosure, the cooling performance of the drive unit can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view perpendicular to the power device side surface of the drive device according to the first embodiment. [Figure 2] FIG. 2 is an external view of the drive device according to the first embodiment. [Figure 3] FIG. 3 is an external view of the heat pipe according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view perpendicular to the direction in which the fins are arranged in the drive device according to the first embodiment. [Figure 5] FIG. 5 is a cross-sectional view perpendicular to the direction in which the fins are arranged in the drive device according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view parallel to the side surface of the power device in the drive device according to the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view of the drive device according to the second embodiment taken along a plane parallel to the side surface on the power device side. [Figure 8] FIG. 8 is a cross-sectional view of a drive device according to a modification of the second embodiment, taken along a plane parallel to the side surface on the power device side. [Figure 9] FIG. 9 is an external view of a heat pipe according to the third embodiment. [Figure 10] FIG. 10 is a cross-sectional view perpendicular to the direction in which the fins are arranged in the drive device according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a driving device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the invention according to the present disclosure is not limited to these embodiments. The drawings are also schematic diagrams.

[0011] The terms used to describe directions are explained below. The ventilation direction is the direction in which the cooling fan guides air. The extension direction is the direction in which the heat pipes extend from the base plate. The width direction is the direction that intersects with the ventilation direction and the extension direction.

[0012] The drawings show the x, y, and z directions. In this disclosure, for convenience, the directions are defined as follows: The x direction is the left-right direction of the drive device. The +x direction is the left direction, and the -x direction is the right direction. The y direction is perpendicular to the x direction and is the depth direction of the drive device. The +y direction is the front direction, and the -y direction is the rear direction. The z direction is perpendicular to the x and y directions and is the up-down direction of the drive device. The +z direction is the up direction, and the -z direction is the down direction. In this disclosure, the x direction is the width direction, the y direction is the extension direction, and the z direction is the ventilation direction, for example. Note that terms such as "up," "down," "right," "left," "front," "rear," "vertical," and "horizontal" are used to represent directions, but they do not limit the arrangement or orientation of the device.

[0013] Embodiment 1 FIG. 1 is a cross-sectional view perpendicular to the power device side surface 3 of a driving device 101 according to embodiment 1. FIG. 2 is an external view of the driving device 101 according to embodiment 1. FIG. 3 is an external view of a heat pipe 21 according to embodiment 1. FIG. 4 is a cross-sectional view perpendicular to the direction in which the fins 50 are arranged in the driving device 101 according to embodiment 1. FIG. 4 is a cross-sectional view taken along line AA in FIG. 1, viewed in the -z direction. FIG. 5 is a cross-sectional view perpendicular to the direction in which the fins 50 are arranged in the driving device 101 according to embodiment 1. FIG. 5 is a cross-sectional view taken along line BB in FIG. 1, viewed in the +z direction.

[0014] The driving device 101 in this disclosure is provided in a control panel of a machine tool. The driving device 101 includes a control unit 10 including a power device 1, and a cooler 20 that cools the control unit 10. The control unit 10 and the cooler 20 are attached to a base plate 2 in the control panel.

[0015] As shown in Figures 1 and 2, the drive unit 101 includes a power device 1, a base plate 2, a heat pipe 21, fins 50, a cooling fan 60, and a ventilation cover 70. The control unit 10 includes the power device 1. The cooler 20 includes the heat pipe 21, fins 50, the cooling fan 60, and the ventilation cover 70. The cooler 20 is a cooler for the drive unit. The illustrated white arrow indicates the direction of the airflow and ventilation direction.

[0016] The base plate 2 in the first embodiment is a flat plate with a rectangular cross section parallel to the ventilation direction. The long side of the cross section of the base plate 2 coincides with the ventilation direction (the vertical direction of the drive device). The short side of the cross section of the base plate 2 coincides with the width direction (the horizontal direction of the drive device).

[0017] A power device 1 is attached to the base plate 2. The surface of the base plate 2 on which the power device 1 is provided is called the power device side surface 3. A heat pipe 21 is provided on the surface of the base plate 2 opposite the power device side surface 3. The surface of the base plate 2 on which the heat pipe 21 is provided is called the heat pipe side surface 4. The power device side surface 3 is the first surface, and the heat pipe side surface 4 is the second surface. The thickness direction of the base plate 2 is the direction from the power device side surface 3 to the heat pipe side surface 4. As shown in Figure 1, the direction from the power device side surface 3 to the heat pipe side surface 4 coincides with the extension direction (the depth direction of the drive unit 101).

[0018] The heat pipe 21 transports heat. The heat pipe 21 transports heat from the power device 1 and cools the power device 1. The heat pipe 21 is made of a material with high thermal conductivity. For example, the heat pipe 21 is made of a metal, such as copper. The heat pipe 21 contains a refrigerant. As shown in FIG. 3 , the heat pipe 21 has a curved shape. The portion of the heat pipe 21 that extends from the power device-side surface 3 to the heat pipe-side surface 4 is called the extension portion 31. The portion that extends in a direction different from the extension portion 31 is called the fixed portion 41. The portion between the extension portion 31 and the fixed portion 41 is called the bent portion 51. As shown in FIGS. 4 and 5 , the heat pipe 21 is fixed to the heat pipe-side surface 4 of the base plate 2. The fixed portion 41 extends in the left-right direction of the drive unit 101 and is fixed to the base plate 2, and the extension portion 31 extends in a direction away from the base plate 2.

[0019] The bent portion 51 is a portion that connects the extension portion 31 and the fixed portion 41. The bent portion 51 may include a part of the fixed portion 41 or may include a part of the extension portion 31. The heat pipe 21 is an integrated unit of the extension portion 31, the fixed portion 41, and the bent portion 51. For example, the heat pipe 21 is formed by bending a single heat pipe.

[0020] As shown in FIG. 3, in the first embodiment, the heat pipe 21 has a flat shape with a uniform thickness. The extension portion 31, the fixed portion 41, and the bent portion 51 are all flat. A flat shape is a shape with a small thickness, such as a flat plate. A flat shape allows heat to be transmitted in the thickness direction more easily than a shape with a large thickness. The cross section of the heat pipe 21 in the first embodiment perpendicular to the thickness direction is rectangular. In the cross section perpendicular to the thickness direction of the heat pipe 21, the longitudinal direction of the heat pipe 21 is the long side direction, and the short side direction of the heat pipe 21 is the short side direction.

[0021] One end of the heat pipe 21 is bent relative to the longitudinal direction of the heat pipe 21. The heat pipe 21 is bent at a predetermined angle relative to the fixed portion 41 to form the extension portion 31. The bending angle of the heat pipe 21 is the angle between the longitudinal direction of the heat pipe 21 at the fixed portion 41 and the longitudinal direction of the heat pipe 21 at the extension portion 31. For example, the extension portion 31 of the heat pipe 21 is bent at 90 degrees relative to the fixed portion 41. As shown in FIG. 4 , the longitudinal direction of the heat pipe 21 at the fixed portion 41 coincides with the width direction (x direction), and the longitudinal direction of the heat pipe 21 at the extension portion 31 coincides with the extension direction (y direction).

[0022] The fixing portion 41 has a flat shape. In the first embodiment, the thickness of the fixing portion 41 is the thickness of the heat pipe 21. A cross section of the fixing portion 41 perpendicular to the longitudinal direction of the heat pipe 21 is referred to as the cross section of the fixing portion 41. The thickness direction of the fixing portion 41 is the short direction in the cross section of the fixing portion 41. The fixing portion 41 is arranged so that the thickness direction of the fixing portion 41 is the thickness direction of the base plate 2. As long as the thickness direction of the fixing portion 41 is not perpendicular to the thickness direction of the base plate 2, the thickness direction of the fixing portion 41 does not necessarily have to be parallel to the thickness direction of the base plate 2. Preferably, the thickness direction of the fixing portion 41 is a direction along the thickness direction of the base plate 2. More preferably, the thickness direction of the fixing portion 41 is parallel to the thickness direction of the base plate 2.

[0023] The fixing portion 41 is fixed to the base plate 2. The surface of the fixing portion 41 facing the heat pipe side surface 4 is referred to as the "facing surface" of the fixing portion 41, and the surface opposite the facing surface of the fixing portion 41 in the thickness direction of the base plate 2 is referred to as the "back surface" of the fixing portion 41. The fixing portion 41 is fixed to the base plate 2 when the facing surface of the fixing portion 41 is in contact with the heat pipe side surface 4, or when the facing surface of the fixing portion 41 is embedded in the base plate 2. The facing surface of the fixing portion 41 is embedded in the base plate 2 when the facing surface of the fixing portion 41 and the back surface of the fixing portion 41 are completely embedded in the base plate 2, or when the facing surface of the fixing portion 41 is embedded in the base plate 2 but the back surface of the fixing portion 41 is not embedded in the base plate 2 and is exposed to air. The fixing portion 41 is fixed to the base plate 2 by soldering or brazing.

[0024] The surface area of ​​the fixed portion 41 is smaller than the surface area of ​​the extension portion 31. Since the heat pipe 21 according to the first embodiment has a flat shape with a uniform thickness, the surface area of ​​the heat pipe 21 is proportional to the longitudinal length of the heat pipe 21. As shown in Fig. 4, in the first embodiment, the longitudinal length (x direction) of the heat pipe 21 at the fixed portion 41 is shorter than the longitudinal length (y direction) of the heat pipe 21 at the extension portion 31.

[0025] FIG. 6 is a cross-sectional view parallel to the power device-side side surface 3 of the driving device 101 according to the first embodiment. FIG. 6 is a cross-sectional view taken along CC in FIG. 1, viewed in the -y direction. A plurality of heat pipes 21 are arranged on the heat pipe-side side surface 4. As shown in FIG. 6, a plurality of heat pipes 21 are arranged in the long side direction and the short side direction in the cross section of the base plate 2. A plurality of heat pipes 21 are arranged at positions projected onto the portion of the base plate where the power devices 1 are arranged.

[0026] In the multiple heat pipes 21, adjacent extension portions 31 in the ventilation direction (z direction) do not overlap with each other when viewed from the ventilation direction. In other words, adjacent extension portions 31 in the ventilation direction are not aligned in a row in the ventilation direction. For example, as shown in FIGS. 4, 5, and 6, the multiple heat pipes 21 are arranged alternately in the ventilation direction. "Alternately" means, for example, that when arranging the multiple heat pipes 21, they are arranged in a first arrangement state, a second arrangement state, a first arrangement state, a second arrangement state, and a first arrangement state along the ventilation direction (z direction). In other words, the first arrangement state and the second arrangement state are arranged alternately along the ventilation direction. In the first embodiment, an example in which the fixing portions 41 are arranged alternately in the ventilation direction is shown as an example in which adjacent extension portions 31 in the ventilation direction do not overlap with each other when viewed from the ventilation direction.

[0027] Of the multiple heat pipes 21, the heat pipes 21 in the first row and the heat pipes 21 in the second row are aligned in the vertical direction (z direction) of the drive device 101 in Fig. 6. In other words, the heat pipes 21 in the first row and the heat pipes 21 in the second row are aligned in the ventilation direction. For example, the heat pipes 21 in the first row are located below the base plate 2 compared to the heat pipes 21 in the second row. The heat pipes 21 in the first row are located upstream in the ventilation direction compared to the heat pipes 21 in the second row.

[0028] Of the multiple heat pipes 21, the heat pipes 21 in the first row and the heat pipes 21 in the second row are aligned in the left-right direction (x direction) of the drive device 101 in FIG. 6. In other words, the heat pipes 21 in the first row and the heat pipes 21 in the second row are aligned in the width direction. For example, the heat pipes 21 in the first row are on the left side of the drive device 101 compared to the heat pipes 21 in the second row. For example, if the right side of the drive device 101 is defined as one side in the left-right direction of the drive device 101, the left side of the drive device 101 is defined as the other side in the left-right direction of the drive device 101. The other side is the opposite side to the one side.

[0029] 6, the fixing portions 41 of the heat pipes 21 in the second row are arranged adjacent to and spaced apart from the fixing portions 41 of the heat pipes 21 in the first row in the vertical direction of the drive device 101. The fixing portions 41 of the heat pipes 21 in the second column are arranged adjacent to and spaced apart from the fixing portions 41 of the heat pipes in the first column in the horizontal direction of the drive device 101.

[0030] The heat pipes 21 include a first-row, first-column heat pipe 21a, a first-row, second-column heat pipe 21b, a second-row, first-column heat pipe 21c, and a second-row, second-column heat pipe 21d. When focusing on the first-row, first-column heat pipe 21a and the second-row, first-column heat pipe 21c, the first-row, first-column heat pipe 21a is referred to as the first heat pipe, and the second-row, first-column heat pipe 21c is referred to as the second heat pipe.

[0031] The arrangement of the multiple heat pipes 21 according to embodiment 1 will be specifically explained using the first row, first column heat pipe 21a, the first row, second column heat pipe 21b, the second row, first column heat pipe 21c, and the second row, second column heat pipe 21d.

[0032] The position of the extension portion 31 of the heat pipe 21 changes depending on the orientation of the heat pipe 21. For example, by arranging the heat pipes 21 while rotating each heat pipe 21 by 180 degrees, the position of the extension portion 31 relative to the fixed portion 41 of the heat pipe 21 is reversed. Here, in the first embodiment, the orientation of the heat pipes 21 is the same. Specifically, the first-row, first-column heat pipe 21a, the first-row, second-column heat pipe 21b, the second-row, first-column heat pipe 21c, and the second-row, second-column heat pipe 21d are arranged so that the extension portion 31 is provided on the right side of the fixed portion 41.

[0033] The fixed portion 41a of the first-row, first-column heat pipe 21a and the fixed portion 41c of the second-row, first-column heat pipe 21c do not coincide in position in the left-right direction of the drive unit 101. When viewed from the direction of ventilation, the fixed portion 41c does not completely overlap the fixed portion 41a, but is shifted to the left. Specifically, in the left-right direction of the drive unit 101, the right end face of the fixed portion 41c of the second-row, first-column heat pipe 21c is to the left of the right end face of the fixed portion 41a of the first-row, first-column heat pipe 21a. The left end face of the fixed portion 41c is to the left of the left end face of the fixed portion 41a.

[0034] In addition, in the left-right direction of the drive device 101, the distance between the right end face of the fixed portion 41a and the right end face of the fixed portion 41c is equal to or greater than the thickness of the extension portion 31a of the first-row, first-column heat pipe 21a. In other words, in the left-right direction of the drive device 101, the distance between the fixed portions 41 is equal to or greater than the length of the extension portion 31 of the heat pipe 21.

[0035] By arranging the fixing portions 41 of the heat pipes 21 in a shifted manner, the extension portions 31 can be arranged in positions where they do not overlap each other without changing the orientation of the heat pipes 21.

[0036] Furthermore, in the left-right direction of the drive unit 101, the extension 31d of the second-row, second-column heat pipe 21d is located between the extension 31a of the first-row, first-column heat pipe 21a and the extension 31b of the first-row, second-column heat pipe 21b. The left end face of the extension 31d is to the right of the right end face of the extension 31a. The right end face of the extension 31d is to the left of the left end face of the extension 31b. With this arrangement, the extensions 31 of the heat pipes 21 aligned in the ventilation direction do not overlap each other.

[0037] 1, the heat pipes 21 are inserted into the fins 50 arranged at intervals in the y direction. The fins 50 have holes that penetrate in the direction in which the fins 50 are arranged, and the extensions 31 of the heat pipes 21 are inserted into the holes. The extension direction of the heat pipes 21 coincides with the direction in which the fins 50 are arranged.

[0038] The cooling fan 60 guides air toward the plurality of heat pipes 21 and the plurality of fins 50. As shown in FIG. 1, the outline arrow indicates the direction of the air, and the cooling fan 60 guides the air in the vertical direction of the drive unit 101. The cooling fan 60 is disposed above the plurality of heat pipes 21 and the plurality of fins 50. The cooling fan 60 is disposed downstream of the plurality of heat pipes 21 and the fins 50 in the airflow direction.

[0039] The ventilation cover 70 is provided near the heat pipes 21 and the fins 50 to prevent the airflow guided to the heat pipes 21 and the fins 50 from escaping. The ventilation cover 70 is provided to surround the heat pipes 21 and the fins 50. As shown in FIGS. 1 and 2 , the ventilation cover 70 is disposed upstream of the cooling fan 60 in the direction of airflow. For example, the cooling fan 60 is installed above the ventilation cover 70.

[0040] The ventilation cover 70 has a shape consisting of three side surfaces and one top surface. The three side surfaces of the ventilation cover 70 are attached to the base plate 2, surrounding the heat pipes 21 and the fins 50. The top surface of the ventilation cover 70 is provided near the cooling fan 60. The top surface of the ventilation cover 70 is provided with ventilation holes 71, which are holes that penetrate in the direction of ventilation, and the air from the cooling fan 60 is guided into the ventilation cover 70 through the ventilation holes 71.

[0041] As shown in FIG. 2 , the base plate 2 has an opening 8 penetrating through it in the thickness direction. The opening 8 is located downstream of the heat pipes 21 and the fins 50 in the airflow direction. A cooling fan 60 is inserted into the opening 8. As shown in FIG. 1 , the cooling fan 60 is disposed in the opening 8 and extends across the base plate 2, protruding from the cooler 20 side toward the power device 1 side. That is, the cooling fan 60 is disposed so that a portion of the cooling fan 60 protrudes toward the power device 1 side. This brings the opening of the cooling fan 60 as close as possible to the base plate 2, increasing the area of ​​the heat pipes 21 and the fins 50 that the air reaches, thereby improving cooling performance. Preferably, the cooling fan 60 protrudes from the base plate 2 toward the power device 1 by a length equivalent to the distance between the housing of the cooling fan 60 and the outer periphery of the opening of the cooling fan 60. Note that the length by which the cooling fan 60 protrudes toward the power device 1 and the position of the cooling fan 60 are not limited to these.

[0042] Furthermore, the driving device 101 of the first embodiment includes a cooling fan cover 80. As shown in FIGS. 1 and 2 , the cooling fan cover 80 is provided to surround the cooling fan 60 that protrudes toward the power device 1. The cooling fan cover 80 is attached to the power device-side side surface 3. By including the cooling fan cover 80, the driving device 101 can efficiently guide the air from the cooling fan 60 to the multiple heat pipes 21 and the multiple fins 50.

[0043] Next, the flow of cooling the driving device 101 will be described.

[0044] The drive unit 101 is equipped with a power device 1 that drives a motor, and the power device 1 generates heat. The heat from the power device 1 is transferred to a base plate 2 that is in contact with the power device 1. A fixing portion 41 of a heat pipe 21 is fixed to the base plate 2, and heat is transferred from the base plate 2 to the fixing portion 41 of the heat pipe 21. When the heat is transferred to the fixing portion 41 of the heat pipe 21, the refrigerant sealed within the heat pipe 21 evaporates at the fixing portion 41. The evaporated refrigerant moves to the extension portion 31. A cooling fan 60 directs air toward the heat pipe 21 and the fins 50, and the extension portion 31 and fins 50 of the heat pipe 21, which are surrounded by a ventilation cover 70, are cooled by the air from the cooling fan 60. As the extension portion 31 is cooled, the refrigerant condenses, and the refrigerant that has returned to a liquid state returns to the fixing portion 41. The fixing portion 41 is also called the evaporation portion because it is the part where the refrigerant evaporates. In addition, the extension portion 31 is also called a condensation portion because it is a portion where the refrigerant is condensed.

[0045] The cooling fan 60 blows air toward the extensions 31 of the heat pipes 21 and the fins 50. When the extensions 31 are arranged overlapping each other in the direction of airflow, the air reaches the extensions 31 of the heat pipes 21 arranged upstream of the airflow. However, the downstream extensions 31 are hidden by the upstream extensions 31 when viewed from the airflow direction, reducing the area of ​​the downstream extensions 31 that are exposed to the airflow. In contrast, in the heat pipes 21 of the first embodiment, the extensions 31 are arranged alternately and do not overlap in the airflow direction. Therefore, the air that hits the upstream extensions 31 tends to flow to the downstream extensions 31 that are offset from the upstream extensions 31, increasing the area of ​​the downstream extensions 31 that are exposed to the airflow. This arrangement allows the heat pipes 21 to be cooled more effectively.

[0046] As described above, the driving device 101 according to the first embodiment includes a base plate 2 having a power device-side side surface 3 (first surface) on which the power device 1 is provided and a heat pipe-side side surface 4 (second surface) opposite the power device-side side surface 3, a plurality of heat pipes 21 each having an extension portion 31 extending from the power device-side side surface 3 toward the heat pipe-side side surface 4, a fixing portion 41 extending in a direction different from the extension direction of the extension portion 31 and fixed to the base plate 2, and a bent portion 51 provided between the extension portion 31 and the fixing portion 41, a plurality of fins 50 into which the heat pipes 21 are inserted, and a cooling fan 60 that guides air to the plurality of heat pipes 21 and the plurality of fins 50. The fixing portion 41 has a flat shape and is arranged so that the thickness direction of the fixing portion 41 is from the power device-side side surface 3 toward the heat pipe-side side surface 4.

[0047] The driving device 101 according to the first embodiment uses a heat pipe 21, which has higher cooling performance than a heat sink, and a plurality of fins 50, thereby improving the cooling performance of the driving device 101. Furthermore, by attaching the fins 50 to the heat pipe 21, the area for dissipating heat is increased, improving the cooling performance compared to the case of using only the heat pipe 21.

[0048] In the driving device 101, the heat pipes 21 are fixed to the base plate 2, so that heat from the power device 1 can be dissipated by the heat pipes 21. In the driving device 101, the fixing portion 41 has a flat shape and is arranged so that the thickness direction of the fixing portion 41 is from the power device side surface 3 to the heat pipe side surface 4, so that the contact area of ​​the fixing portion 41 with the base plate 2 is increased, improving cooling performance. Furthermore, because the thickness of the fixing portion 41 is thin, the temperature distribution of the fixing portion 41 in the thickness direction is not uneven, and heat is transmitted efficiently.

[0049] One end of the heat pipe 21 is bent to form the fixed portion 41 and the extension portion 31, so that the heat pipe 21 of the drive unit 101 has one extension portion 31 provided for one fixed portion 41. This prevents the refrigerant from becoming unevenly distributed compared to when multiple extension portions 31 are provided for one fixed portion 41, improving the cooling performance of the heat pipe 21. Furthermore, because the heat pipe 21 according to the first embodiment is bent, it is easier to process compared to when multiple extension portions 31 are provided for one fixed portion 41.

[0050] The cooling performance of the drive unit 101 is improved by using the cooling fan 60 to guide air to the plurality of heat pipes 21 and the plurality of fins 50.

[0051] Furthermore, the drive device 101 includes a ventilation cover 70 that is provided to surround the plurality of heat pipes 21 and the plurality of fins 50.

[0052] The drive unit 101 guides airflow by the cooling fan 60, and by further providing the ventilation cover 70, the airflow can be guided intensively to the plurality of heat pipes 21 and the plurality of fins 50.

[0053] The plurality of heat pipes 21 include a first row, first column heat pipe 21a (first heat pipe) and a second row, first column heat pipe 21c (second heat pipe) aligned in the ventilation direction, and the extension portion 31a of the first row, first column heat pipe 21a and the extension portion 31c of the second row, first column heat pipe 21c do not overlap when viewed from the ventilation direction.

[0054] In the drive unit 101, the extensions 31 of the heat pipes 21 do not overlap, so that air can be efficiently sent to each extension 31. In the drive unit 101, the heat pipes 21 are staggered in the ventilation direction, so that air that avoids the extensions 31a of the first-row, first-column heat pipes 21a flows to the position of the extensions 31c of the second-row, first-column heat pipes 21c, thereby efficiently cooling the heat pipes 21. Furthermore, by staggering the heat pipes 21 in the ventilation direction, air can hit the heat pipes 21 and disrupt the air flow, improving the cooling performance of the drive unit 101. Furthermore, by staggering the heat pipes 21 in the ventilation direction, air can hit the heat pipes 21 and disrupt the air flow, improving the cooling performance of the drive unit 101.

[0055] In the width direction, which is a direction intersecting the ventilation direction, the fixed portion 41c of the second-row, first-column heat pipe 21c is shifted to one side compared to the fixed portion 41a of the first-row, first-column heat pipe 21a. In other words, the fixed portion 41c is shifted to one side compared to the fixed portion 41a.

[0056] The driving device 101 has improved cooling performance because the extensions 31 of the heat pipes 21 do not overlap due to the arrangement of the fixing parts 41. Furthermore, the position of the fixing parts 41 is not biased in the width direction, so the heat distribution on the base plate 2 is not uneven, allowing for efficient cooling.

[0057] The base plate 2 has an opening 8 penetrating through the thickness of the base plate 2, which is the direction from the power device side surface 3 toward the heat pipe side surface 4, and the cooling fan 60 has a cooling fan cover 80 that protrudes partially toward the power device 1 side and is provided in the opening 8 to surround the cooling fan 60 on the power device 1 side.

[0058] In the drive unit 101, a portion of the cooling fan 60 protrudes toward the power device 1, bringing the opening of the cooling fan 60 closer to the base plate 2. This makes it easier for the air from the cooling fan 60 to reach the portions of the fins 50 that are closest to the base plate 2, thereby cooling the entire fins 50. The drive unit 101 is further provided with a cooling fan cover 80, which allows the air to be directed in a concentrated manner to the multiple heat pipes 21 and the multiple fins 50.

[0059] Furthermore, in the drive unit 101, an opening 8 is provided in the base plate 2, and a portion of the cooling fan 60 protrudes toward the power device 1 and is provided in the opening 8, so that the cooling fan 60 can be arranged on both the heat pipe 21 side and the power device 1 side across the base plate 2. This increases the arrangement space for the cooling fan 60, allowing a cooling fan 60 with a larger air volume to be arranged, improving cooling performance. Furthermore, since a fan with a larger air volume can be arranged, the number of fans can be reduced.

[0060] Furthermore, the extension portion 31 of the heat pipe 21 has a flat shape. The bent portion 51 of the heat pipe 21 also has a flat shape. That is, the extension portion 31, the fixed portion 41, and the bent portion 51 of the heat pipe 21 all have a flat shape.

[0061] Because the extension portion 31 of the drive unit 101 has a flat shape, it is less likely to interfere with the flow of air from the cooling fan 60. This makes it possible to prevent a decrease in the air volume of the cooling fan 60. The drive unit 101 is easy to manufacture because the flat extension portion 31, fixed portion 41, and bent portion 51 can be manufactured by simply bending the flat heat pipe 21.

[0062] In the heat pipe 21, the surface area of ​​the extension portion 31 is larger than the surface area of ​​the fixed portion 41.

[0063] Because the extension portion 31 is cooled by heat exchange between the air and the refrigerant, the extension portion 31 has a lower thermal conductivity than the fixed portion 41. By making the surface area of ​​the extension portion 31 larger than the surface area of ​​the fixed portion 41, the area to be cooled by the extension portion 31 increases, improving the cooling effect of the extension portion 31 and the cooling performance of the entire drive unit 101.

[0064] Although the cooling fan 60 in embodiment 1 is positioned downstream of the multiple heat pipes 21 and the multiple fins 50 in the ventilation direction, the cooling fan 60 may be positioned upstream of the multiple heat pipes 21 and the multiple fins 50 in the ventilation direction as long as the cooling fan 60 is configured to direct air to the multiple heat pipes 21 and the multiple fins 50.

[0065] In the first embodiment, the ventilation cover 70 has an upper surface on which the ventilation holes 71 are provided, but it may also have a lower surface that is opposite to the upper surface in the ventilation direction. In this case, the lower surface also has ventilation holes 71 so that the air can be guided. The ventilation cover 70 may also be open and have no upper or lower surfaces. In other words, the ventilation cover 70 may have only side surfaces.

[0066] Embodiment 2 Next, a second embodiment will be described with reference to Fig. 7. A driving device 102 according to the second embodiment differs from the first embodiment in the arrangement of the plurality of heat pipes.

[0067] 7 is a cross-sectional view parallel to the power device side surface 3 of the driving device 102 according to the second embodiment. The same components as those in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted.

[0068] In the driving device 102 according to the second embodiment, the positions of the extension portions 32 are different relative to the fixing portions 42 of the heat pipes 22. As a result, the plurality of heat pipes 22 are arranged in positions where the extension portions 32 adjacent to each other in the ventilation direction do not overlap each other when viewed from the ventilation direction.

[0069] The arrangement of the multiple heat pipes 22 according to the second embodiment will be specifically explained using the first row, first column heat pipe 22a, the first row, second column heat pipe 22b, the second row, first column heat pipe 22c, and the second row, second column heat pipe 22d.

[0070] As shown in Figure 7, the heat pipes 22 are arranged in different directions. In the second embodiment, the heat pipes 21 are arranged rotated by 180 degrees. That is, adjacent heat pipes 22 in the airflow direction are arranged in an inverted manner. Specifically, the first-row, first-column heat pipe 22a and the first-row, second-column heat pipe 22b are arranged such that the extensions 32a and 32b are located on the left side of the fixed portions 42a and 42b, respectively. On the other hand, the second-row, first-column heat pipe 22c and the second-row, second-column heat pipe 22d are arranged such that the extensions 32c and 32d are located on the right side of the fixed portions 42c and 42d, respectively.

[0071] For example, in the first-row, first-column heat pipe 22a and the second-row, first-column heat pipe 22c, the position of the extension portion 32c relative to the fixed portion 42c of the second-row, first-column heat pipe 22c is opposite in the left-right direction of the drive unit to the position of the extension portion 32a relative to the fixed portion 42a of the first-row, first-column heat pipe 22a. In other words, the first-row, first-column heat pipe 22a and the second-row, first-column heat pipe 22c have different positions of the extension portion 32 relative to the fixed portion 42 in the left-right direction of the drive unit 101.

[0072] The fixed portion 42a of the first-row, first-column heat pipe 22a and the fixed portion 42c of the second-row, first-column heat pipe 22c are positioned in the same position in the left-right direction of the drive unit 101. As shown in Fig. 7, the fixed portion 42c of the second-row, first-column heat pipe 22c is arranged in the same position as the fixed portion 42a of the first-row, first-column heat pipe 22a in the left-right direction of the drive unit 101. When viewed from the direction of ventilation, the fixed portion 42c of the second-row, first-column heat pipe 22c overlaps with the fixed portion 42a of the first-row, first-column heat pipe 22a, and they are arranged in a row.

[0073] In the left-right direction of the drive unit 102, the right end face of the fixed portion 42c of the second-row, first-column heat pipe 22c is located at the same position as the right end face of the fixed portion 42a of the first-row, first-column heat pipe 22a. The left end face of the fixed portion 42c is located at the same position as the left end face of the fixed portion 42a.

[0074] The positions of the extension parts 32 of the multiple heat pipes 22 relative to the fixed parts 42 are different, so that even if the fixed parts 42 are arranged in the same position when viewed from the ventilation direction, the extension parts 32 adjacent to each other in the ventilation direction can be arranged in positions that do not overlap each other.

[0075] As described above, in the second embodiment, the example has been shown in which the fixing parts 42 of the plurality of heat pipes 22 are arranged at the same position when viewed from the direction of airflow, but the fixing parts 42 may be arranged offset from each other.

[0076] As a modification of the second embodiment, a drive unit 103 will be described in which the positions of the extension portions 33 of the heat pipes 23 relative to the fixed portions 43 are different, and the fixed portions 43 are arranged alternately in the ventilation direction. As a result, the multiple heat pipes 23 are arranged so that the extension portions 33 do not overlap each other when viewed from the ventilation direction. The modification of the second embodiment is a combination of the first and second embodiments.

[0077] A modification of the second embodiment will be described with reference to Fig. 8. Fig. 8 is a cross-sectional view of a driving device 103 according to a modification of the second embodiment, taken along a plane parallel to the power device side surface 3.

[0078] The arrangement of the multiple heat pipes 23 according to a modified example of embodiment 2 will be specifically explained using the first row, first column heat pipe 23a, the first row, second column heat pipe 23b, the second row, first column heat pipe 23c, and the second row, second column heat pipe 23d.

[0079] As in the second embodiment, adjacent heat pipes 23 in the ventilation direction are arranged in an inverted manner. Focusing on the first-row, first-column heat pipe 23a and the second-row, first-column heat pipe 23c, the positions of the extension portions 33 relative to the fixed portion 43 are different in the left-right direction of the drive unit 103. As shown in Fig. 8, the position of the extension portion 33c relative to the fixed portion 43c of the second-row, first-column heat pipe 23c is opposite the position of the extension portion 33a relative to the fixed portion 43a of the first-row, first-column heat pipe 23a in the left-right direction of the drive unit.

[0080] The fixing portion 43a of the first-row, first-column heat pipe 23a and the fixing portion 43c of the second-row, first-column heat pipe 23c are not aligned in the left-right direction of the drive unit 103. As shown in Fig. 8, the fixing portion 43c of the second-row, first-column heat pipe 22c is located to the left of the fixing portion 43a of the first-row, first-column heat pipe 23a.

[0081] In the left-right direction of the drive unit 103, the right end face of the fixed portion 43c of the second-row, first-column heat pipe 23c is to the right of the right end face of the fixed portion 43a of the first-row, first-column heat pipe 23a, and the left end face of the fixed portion 43c is to the left of the left end face of the fixed portion 43a.

[0082] The heat pipes 23 can be arranged in positions where the extensions 33 do not overlap each other by displacing the fixed portions 43 from one another and disposing the extensions 33 at different positions relative to the fixed portions 43.

[0083] In the second embodiment and the modified example, the position of the extension portion 33 relative to the fixed portion 43 is different, which increases the degree of freedom in arranging the heat pipes 22, 23 compared to the first embodiment. As a result, in the left-right direction of the drive device 102, 103, the distance between the right end face of the fixed portion 42a, 43a and the right end face of the fixed portion 42c, 43c may be equal to or less than the thickness of the extension portion 32a, 33a of the first-row, first-column heat pipe 22a, 23a. In other words, in the left-right direction of the drive device 102, 103, the distance between the fixed portions 42, 43 may be equal to or less than the length of the extension portion 32, 33 of the heat pipe 22, 23.

[0084] As described above, in the driving devices 102, 103 according to the second embodiment and the modified examples, the positions of the extension portions 32c, 33c relative to the fixed portions 42c, 43c in the second row, first column heat pipes 22c, 23c (second heat pipes) are opposite to the positions of the extension portions 32a, 33a relative to the fixed portions 42a, 43a in the first row, first column heat pipes 22a, 23a (first heat pipes).

[0085] As in the first embodiment, the cooling performance of the drive units 102, 103 is improved. In addition to this effect, the following effect can be achieved: In the drive units 102, 103, the positions of the extensions 32, 33 relative to the fixed parts 42, 43 of the heat pipes 22, 23 aligned in the ventilation direction are different, so that the extensions 32, 33 of the heat pipes 22, 23 do not overlap each other, and air can be efficiently sent to each extension 32, 33.

[0086] Furthermore, in the second embodiment and its modifications, the positions of the extensions 32, 33 relative to the fixed portions 42, 43 are different, which allows for greater freedom in the placement of the fixed portions 42, 43 than in the first embodiment. Furthermore, the distance between the fixed portions 42, 43 can be made shorter than in the first embodiment, which allows for a smaller placement area for the heat pipes 22, 23. This allows for a more compact device. Furthermore, since more heat pipes 22, 23 can be placed in a given area, the cooling performance is further improved.

[0087] Embodiment 3 Next, a third embodiment will be described with reference to Figures 9 and 10. A driving device 104 according to the third embodiment has a different shape of an extension portion from that of the first embodiment.

[0088] Fig. 9 is an external view of a heat pipe 24 according to embodiment 3. Fig. 10 is a cross-sectional view perpendicular to the direction in which fins 50 are arranged in a drive unit 104 according to embodiment 3. Fig. 10 is a cross-sectional view viewed in the -z direction. Note that the same components as those in embodiments 1 and 2 are designated by the same reference numerals, and descriptions thereof will be omitted.

[0089] 9 and 10, the heat pipe 24 has an extension 34 that has a different shape from the fixed portion 44. For example, the fixed portion 44 has a flat shape, while the extension 34 has a cylindrical shape. The extension 34 has a cylindrical shape with a refrigerant sealed inside, and the tip is sealed. The bent portion 54 is the portion that connects the extension 34 and the fixed portion 44.

[0090] The fins 50 have cylindrical holes formed therein so that the cylindrical extensions 34 can pass through, and the heat pipes 24 are inserted therein. Note that the cross section of the cylindrical shape does not have to be a perfect circle, and may be an ellipse or the like.

[0091] As in the first embodiment, the heat pipes 24 are arranged such that the extensions 34 adjacent to each other in the ventilation direction do not overlap each other when viewed from the ventilation direction.

[0092] As described above, in the driving device 104 according to the third embodiment, the extension portion 34 of the heat pipe 24 has a different shape from the fixed portion 44. The extension portion 34 of the heat pipe 24 has a circular pipe shape.

[0093] As in the first embodiment, the cooling performance of the drive unit 104 is improved. In addition to this effect, the following effects can be achieved. Since the extension 34 of the heat pipe 24 has a shape other than a flat shape, the processing precision required for the bending process can be relaxed. Furthermore, since the extension 34 of the heat pipe 21 has a cylindrical shape, it can be easily attached to the fins 50. As a result, the mass productivity of the drive unit 104 can be improved.

[0094] The configurations described in the above embodiments are merely examples of the contents of the present disclosure, and the techniques of the embodiments may be combined with each other or with other known techniques. Furthermore, it is also possible to omit or modify part of the configurations without departing from the gist of the present disclosure. [Explanation of symbols]

[0095] 101, 102, 103, 104 drive unit, 1 power device, 2 base plate, 3 power device side surface, 4 heat pipe side surface, 8 opening, 10 control unit, 20 cooler, 21, 22, 23, 24 heat pipe, 21a, 22a, 23a first row first column heat pipe, 21b, 22b, 23b first row second column heat pipe, 21c, 22c, 23c second row first column heat pipe, 21d, 22d, 23d second row second column heat pipe, 31, 31a, 31b, 31c, 31d, 32, 32a, 32b, 32c, 32d, 33, 33a, 33b, 33c, 33d, 34 Extensions, 41, 41a, 41b, 41c, 41d, 42, 42a, 42b, 42c, 42d, 43, 43a, 43b, 43c, 43d, 44 Extensions, 50 Fins, 51, 54 Bends, 60 Cooling fan, 70 Ventilation cover, 71 Ventilation holes, 80 Cooling fan cover.

Claims

1. a base plate having a first surface on which a power device is provided and a second surface opposite to the first surface; a plurality of heat pipes each having an extension portion extending from the first surface toward the second surface, a fixed portion extending in a direction different from the extension direction of the extension portion and fixed to the base plate, and a bent portion provided between the extension portion and the fixed portion; a plurality of fins into which the plurality of heat pipes are inserted; a cooling fan that guides airflow to the plurality of heat pipes and the plurality of fins; Equipped with The direction in which the cooling fan guides the air is defined as a ventilation direction, The fixing portion has a flat shape, the fixing portion is disposed such that a thickness direction of the fixing portion is a direction from the first surface toward the second surface, The extension has a flat shape, The drive device, wherein the extension portion is disposed so that a thickness direction of the extension portion does not coincide with the airflow direction.

2. The plurality of heat pipes include a first heat pipe and a second heat pipe aligned in the ventilation direction, 2. The drive device according to claim 1, wherein the extension of the first heat pipe and the extension of the second heat pipe do not overlap when viewed from the direction of airflow.

3. 3. The drive device according to claim 2, wherein in the width direction, which is a direction intersecting the ventilation direction, the fixed portion of the second heat pipe is positioned shifted to one side compared to the fixed portion of the first heat pipe.

4. 4. The drive device according to claim 2, wherein the extension portion of the second heat pipe is positioned on an opposite side to the fixed portion of the first heat pipe.

5. the base plate has an opening passing through in a direction from the first surface to the second surface, the cooling fan is provided in the opening and has a portion protruding toward the power device; 4. The drive device according to claim 1, further comprising a fan cover that surrounds the cooling fan on the power device side.

6. 4. The drive unit according to claim 1, wherein the surface area of ​​the extension portion of the heat pipe is larger than the surface area of ​​the fixed portion.

7. The thickness direction of the extension portion is the short side direction of the extension portion in a cross section perpendicular to the extension direction of the extension portion, The drive unit according to claim 1 , wherein the extension portion is disposed so that a long side direction of the extension portion coincides with the airflow direction in a cross section perpendicular to the extending direction of the extension portion.

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