Drive device

Abstract

This drive device is provided with a base plate (2) having a first surface (3) on which a power device (1) is provided, and a second surface (4) being a surface on the opposite side from the first surface (3), a plurality of heat pipes (21) having an extension part (31) extending in the direction from the first surface (3) toward the second surface (4), a fixed part (41) extending in a direction different from the extending direction of the extension part (31) and fixed to the base plate (2), and a bent part (51) provided between the extension part (31) and the fixed part (41), a plurality of fins (50) into which the plurality of heat pipes (21) are inserted, and a cooling fan (60) for guiding air to the plurality of heat pipes (21) and the plurality of fins (50). The fixed part (41) has a flat shape. The fixed part (41) is disposed in such a manner that the thickness direction of the fixed part (41) is the direction from the first surface (3) toward the second surface (4).

Description

Drive device

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

[0002] In the fields of machine tools and FA (Factory Automation), high output and miniaturization of drive devices for driving machines are required. A drive device includes power devices such as semiconductor elements and capacitors for controlling the current supplied to a motor. Since the power device generates heat while driving, it is cooled by a heat sink, a fan, or the like.

[0003] Patent Document 1 discloses a drive device including a switching element for driving a motor and a heat sink on which the switching element is mounted. The switching element is cooled by the heat sink taking away the heat of the switching element.

[0004] Japanese Unexamined Patent Application Publication No. 2017 - 59759

[0005] When the drive device is miniaturized, the heat generation density increases, so a cooler with high cooling performance is required. Since the cooling performance of the heat sink depends on the size of the heat sink, the drive device disclosed in Patent Document 1 has limited improvement in cooling performance.

[0006] The present disclosure has been made to solve the above problems, and an object thereof is to improve the cooling performance of the drive device.

[0007] The 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, an extension portion extending in a direction from the first surface toward the second surface, a fixing portion extending in a direction different from the direction in which the extension portion extends and fixed to the base plate, and a plurality of heat pipes having a bent portion provided between the extension portion and the fixing portion, a plurality of fins into which the plurality of heat pipes are inserted, and a cooling fan for guiding wind to the plurality of heat pipes and the plurality of fins. The fixing portion has a flat shape, and the fixing portion is arranged such that the thickness direction of the fixing portion is the direction from the first surface toward the second surface.

[0008] According to the present disclosure, the cooling performance of the drive device can be improved.

[0009] Figure 1 is a cross-sectional view perpendicular to the power device side surface of the drive device according to Embodiment 1. Figure 2 is an external view of the drive device according to Embodiment 1. Figure 3 is an external view of the heat pipe according to Embodiment 1. Figure 4 is a cross-sectional view perpendicular to the direction in which the fins are arranged in the drive device according to Embodiment 1. Figure 5 is a cross-sectional view perpendicular to the direction in which the fins are arranged in the drive device according to Embodiment 1. Figure 6 is a cross-sectional view parallel to the power device side surface of the drive device according to Embodiment 1. Figure 7 is a cross-sectional view parallel to the power device side surface of the drive device according to Embodiment 2. Figure 8 is a cross-sectional view parallel to the power device side surface of a modified version of Embodiment 2. Figure 9 is an external view of the heat pipe according to Embodiment 3. Figure 10 is a cross-sectional view perpendicular to the direction in which the fins are arranged in the drive device according to Embodiment 3.

[0010] The drive device according to an embodiment of this disclosure will be described in detail below with reference to the drawings. Note that this embodiment does not limit the invention according to this disclosure. Also, the drawings are schematic diagrams.

[0011] The following terms describe directions. The ventilation direction is the direction in which the cooling fan directs the 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 the ventilation direction and the extension direction.

[0012] The drawings indicate the x, y, and z directions. For convenience, in this disclosure, directions are defined as follows: The x direction is the left-right direction of the drive unit. 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 unit. 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 unit. The +z direction is the up direction, and the -z direction is the down direction. In this disclosure, the x direction is used as an example of the width direction, the y direction as the extension direction, and the z direction as the ventilation direction. 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 and orientation of the device.

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

[0014] The drive unit 101 in this disclosure is installed in the control panel of a machine tool. The drive unit 101 comprises a control unit 10 including a power device 1 and a cooler 20 for cooling the control unit 10. The control unit 10 and the cooler 20 are mounted on a base plate 2 inside the control panel.

[0015] As shown in Figures 1 and 2, the drive unit 101 comprises 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 has the power device 1. The cooler 20 has a heat pipe 21, fins 50, a cooling fan 60, and a ventilation cover 70. The cooler 20 is a cooler for the drive unit. The white arrows shown indicate the direction of airflow and the direction of ventilation.

[0016] In Embodiment 1, the base plate 2 is a flat plate with a rectangular cross-sectional shape parallel to the ventilation direction. The longer side of the cross-section of the base plate 2 coincides with the ventilation direction (up and down direction of the drive device). The shorter side of the cross-section of the base plate 2 coincides with the width direction (left and right direction of the drive device).

[0017] A power device 1 is attached to the base plate 2. The side of the base plate 2 on which the power device 1 is mounted is called the power device side surface 3. A heat pipe 21 is provided on the side of the base plate 2 opposite to the power device side surface 3. The side of the base plate 2 on which the heat pipe 21 is mounted 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 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, thereby cooling the power device 1. The heat pipe 21 is made of a material with high thermal conductivity. For example, the material of the heat pipe 21 is metal, such as copper. The heat pipe 21 also has a coolant sealed inside. As shown in Figure 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 toward 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, and the portion provided between the extension portion 31 and the fixed portion 41 is called the curved portion 51. As shown in Figures 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 away from the base plate 2.

[0019] The bent portion 51 is the part 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 a part of the extension portion 31. The heat pipe 21 is an integral part 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 Figure 3, in Embodiment 1, the heat pipe 21 has a uniform, flattened shape. The extension portion 31, the fixing portion 41, and the bent portion 51 are flattened. A flattened shape is a shape with a thin thickness, for example, a flat plate shape. Heat is more easily transferred in the thickness direction to a flattened shape than to a shape with a larger thickness. The heat pipe 21 of Embodiment 1 has a rectangular cross-section perpendicular to the thickness direction. 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] The heat pipe 21 has one end bent relative to its longitudinal direction. The heat pipe 21 is bent at a predetermined angle relative to the fixed part 41 to form the extension part 31. The bending angle of the heat pipe 21 is the angle formed by the longitudinal direction of the heat pipe 21 at the fixed part 41 and the longitudinal direction of the heat pipe 21 at the extension part 31. For example, the extension part 31 of the heat pipe 21 is formed by bending 90 degrees relative to the fixed part 41. As shown in Figure 4, the longitudinal direction of the heat pipe 21 at the fixed part 41 coincides with the width direction (x direction), and the longitudinal direction of the heat pipe 21 at the extension part 31 coincides with the extension direction (y direction).

[0022] The fixing portion 41 is flattened. In Embodiment 1, the thickness of the fixing portion 41 is the thickness of the heat pipe 21. The cross section of the fixing portion 41 perpendicular to the longitudinal direction of the heat pipe 21 is called 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 such that the thickness direction of the fixing portion 41 is 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, as long as it is not perpendicular to the thickness direction of the base plate 2. Preferably, the thickness direction of the fixing portion 41 is in 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 part 41 is fixed to the base plate 2. The surface of the fixing part 41 facing the heat pipe side surface 4 is called the opposing surface of the fixing part 41, and the surface of the fixing part 41 opposite to the opposing surface in the thickness direction of the base plate 2 is called the back surface of the fixing part 41. The fixing part 41 being fixed to the base plate 2 means that the opposing surface of the fixing part 41 is in contact with the heat pipe side surface 4, or that the opposing surface of the fixing part 41 is embedded in the base plate 2. Furthermore, the state in which the opposing surface of the fixing part 41 is embedded in the base plate 2 means that both the opposing surface and the back surface of the fixing part 41 are completely embedded in the base plate 2, or that the opposing surface of the fixing part 41 is embedded in the base plate 2 but the back surface of the fixing part 41 is not embedded in the base plate 2 and is exposed to the air. The fixing part 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 Embodiment 1 has a uniform thickness and a flat shape, the surface area of ​​the heat pipe 21 is proportional to the length of the heat pipe 21 in the longitudinal direction. As shown in Figure 4, in Embodiment 1, the length of the heat pipe 21 in the longitudinal direction (x direction) at the fixed portion 41 is shorter than the length of the heat pipe 21 in the longitudinal direction (y direction) at the extension portion 31.

[0025] Figure 6 is a cross-sectional view of the drive unit 101 according to Embodiment 1, parallel to the power device side surface 3. Figure 6 is a cross-sectional view taken along the line C-C in Figure 1, looking in the -y direction. Multiple heat pipes 21 are arranged on the heat pipe side surface 4. As shown in Figure 6, multiple heat pipes 21 are arranged in the long and short directions of the cross-section of the base plate 2. Multiple heat pipes 21 are provided at positions on the base plate that are projected from the portion where the power device 1 is provided.

[0026] Multiple heat pipes 21 are arranged such that adjacent extensions 31 in the ventilation direction (z-direction) do not overlap when viewed from the ventilation direction. In other words, adjacent extensions 31 in the ventilation direction do not line up in a row in the ventilation direction. For example, as shown in Figures 4, 5, and 6, multiple heat pipes 21 are arranged alternately in the ventilation direction. Alternate means, for example, when arranging multiple heat pipes 21, that 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. Embodiment 1 shows an example where adjacent extensions 31 in the ventilation direction do not overlap when viewed from the ventilation direction, in which the fixing parts 41 are arranged alternately in the ventilation direction.

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

[0028] Of the multiple heat pipes 21, the first row of heat pipes 21 and the second row of heat pipes 21 are arranged in the left-right direction (x-direction) of the drive unit 101 in Figure 6. In other words, the first row of heat pipes 21 and the second row of heat pipes 21 are arranged in the width direction. For example, the first row of heat pipes 21 is to the left of the drive unit 101 compared to the second row of heat pipes 21. For example, if the right side of the drive unit 101 is considered one side in the left-right direction of the drive unit 101, then the left side of the drive unit 101 is considered the other side in the left-right direction of the drive unit 101. The other side is the opposite side from the one side.

[0029] As shown in Figure 6, the fixing portion 41 of the second row of heat pipes 21 is positioned at a distance from the fixing portion 41 of the first row of heat pipes 21 in the vertical direction of the drive unit 101. The fixing portion 41 of the second column of heat pipes 21 is positioned at a distance from the fixing portion 41 of the first column of heat pipes in the left-right direction of the drive unit 101.

[0030] The multiple heat pipes 21 include a heat pipe 21a in the first row and first column, a heat pipe 21b in the first row and second column, a heat pipe 21c in the second row and first column, and a heat pipe 21d in the second row and second column. When focusing on the heat pipes 21a in the first row and first column and the heat pipes 21c in the second row and first column, the heat pipe 21a in the first row and first column is called the first heat pipe, and the heat pipe 21c in the second row and first column is called the second heat pipe.

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

[0032] The position of the extension portion 31 of the heat pipe 21 changes depending on the orientation in which the heat pipe 21 is arranged. For example, by rotating each of the multiple heat pipes 21 by 180 degrees and arranging them, the position of the extension portion 31 of the heat pipe 21 relative to the fixing portion 41 is reversed. In this embodiment 1, the orientation in which the heat pipes 21 are arranged is the same for all of them. Specifically, the heat pipe 21a in the first row and first column, the heat pipe 21b in the first row and second column, the heat pipe 21c in the second row and first column, and the heat pipe 21d in the second row are arranged so that the extension portion 31 is provided on the right side relative to the fixing portion 41.

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

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

[0035] Multiple heat pipes 21 can be positioned so that their extensions 31 do not overlap, without changing the orientation of the heat pipes 21, because the fixing portions 41 are staggered.

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

[0037] As shown in Figure 1, multiple heat pipes 21 are inserted into multiple fins 50 that are spaced apart in the y-direction. The fins 50 have holes that penetrate in the direction in which the multiple fins 50 are aligned, and the extensions 31 of the heat pipes 21 are inserted into these holes. The extension direction of the heat pipes 21 coincides with the direction in which the multiple fins 50 are aligned.

[0038] The cooling fan 60 directs airflow toward the multiple heat pipes 21 and the multiple fins 50. As shown in Figure 1, the outlined white arrows indicate the direction of the airflow, and the cooling fan 60 directs airflow in the vertical direction of the drive unit 101. The cooling fan 60 is positioned above the multiple heat pipes 21 and the multiple fins 50. The cooling fan 60 is positioned downstream of the multiple heat pipes 21 and the multiple fins 50 in the airflow direction.

[0039] The ventilation cover 70 is positioned near the heat pipes 21 and fins 50 to prevent airflow from escaping to the heat pipes 21 and fins 50. The ventilation cover 70 surrounds the heat pipes 21 and fins 50. As shown in Figures 1 and 2, the ventilation cover 70 is positioned upstream of the cooling fan 60 in the direction of airflow. For example, the cooling fan 60 is installed on top of the ventilation cover 70.

[0040] The ventilation cover 70 has a shape consisting of three sides and one top surface. The three sides of the ventilation cover 70 surround the multiple heat pipes 21 and the multiple fins 50 and are attached to the base plate 2. The top surface of the ventilation cover 70 is located near the cooling fan 60. The top surface of the ventilation cover 70 is provided with ventilation holes 71 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 Figure 2, the base plate 2 is provided with an opening 8 that penetrates in the thickness direction of the base plate 2. The opening 8 is located downstream of the multiple heat pipes 21 and the multiple fins 50 in the ventilation direction. A cooling fan 60 is inserted into the opening 8. As shown in Figure 1, the cooling fan 60 provided in the opening 8 is positioned to protrude from the cooler 20 side to the power device 1 side, straddling the base plate 2. In other words, a portion of the cooling fan 60 protrudes toward the power device 1 side. This allows the opening of the cooling fan 60 to be as close to the base plate 2 as possible, increasing the surface area on the multiple heat pipes 21 and the multiple fins 50 that are exposed to airflow, thereby improving cooling performance. Preferably, the cooling fan 60 protrudes from the base plate 2 toward the power device 1 side by a length equal to the distance between the housing of the cooling fan 60 and the outer circumference of the opening of the cooling fan 60. However, the length of the cooling fan 60 protruding toward the power device 1 side and the position of the cooling fan 60 are not limited to this.

[0042] Furthermore, the drive unit 101 of the first embodiment includes a cooling fan cover 80. As shown in Figures 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 surface 3. By including the cooling fan cover 80, the drive unit 101 can efficiently guide the airflow from the cooling fan 60 to the multiple heat pipes 21 and the multiple fins 50.

[0043] Next, we will explain the cooling process for the drive unit 101.

[0044] The drive device 101 includes a power device 1 that drives a motor, and the power device 1 generates heat. The heat of the power device 1 is transmitted to the base plate 2 that contacts the power device 1. A fixing portion 41 of the heat pipe 21 is fixed to the base plate 2, and the heat is transmitted from the base plate 2 to the fixing portion 41 of the heat pipe 21. When heat is transmitted to the fixing portion 41 of the heat pipe 21, the refrigerant encapsulated in the heat pipe 21 evaporates at the fixing portion 41. The evaporated refrigerant moves to the extension portion 31. Wind is guided from the cooling fan 60 to the heat pipe 21 and the fins 50, and the extension portion 31 of the heat pipe 21 and the fins 50 surrounded by the ventilation cover 70 are cooled by the wind of the cooling fan 60. When the extension portion 31 is cooled, the refrigerant condenses, and the refrigerant that has returned to the liquid state returns to the fixing portion 41. Since the fixing portion 41 is a portion where the refrigerant evaporates, it is also referred to as an evaporation portion. Also, since the extension portion 31 is a portion where the refrigerant condenses, it is also referred to as a condensation portion.

[0045] The cooling fan 60 blows wind toward the extension portions 31 of the plurality of heat pipes 21 and the plurality of fins 50. Here, when the extension portions 31 are arranged overlapping in the ventilation direction, the wind hits the extension portion 31 of the heat pipe 21 arranged on the upstream side of the wind among the plurality of heat pipes 21, but the downstream extension portion 31 is hidden by the upstream extension portion 31 when viewed from the ventilation direction, so the area of the downstream extension portion 31 that the wind hits is reduced. On the other hand, in the heat pipe 21 of Embodiment 1, the extension portions 31 are arranged alternately without overlapping in the ventilation direction. Therefore, the wind hitting the upstream extension portion 31 easily flows to the downstream extension portion 31 arranged at a position shifted from the upstream extension portion 31, and the area of the downstream extension portion 31 that the wind hits is also large. With this arrangement, the heat pipe 21 can be cooled more effectively.

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

[0047] By using the heat pipes 21 and the plurality of fins 50 having higher cooling performance than a heat sink, the cooling performance of the drive device 101 is improved in the drive device 101 according to Embodiment 1. Further, by attaching the fins 50 to the heat pipes 21, the area for radiating heat increases, and the cooling performance is improved compared to the case of only the heat pipes 21.

[0048] In the drive device 101, since the heat pipes 21 are fixed to the base plate 2, heat from the power device 1 can be radiated by the heat pipes 21. In the drive device 101, since the fixing portion 41 has a flat shape and the fixing portion 41 is arranged such that the thickness direction of the fixing portion 41 is the direction from the power device side surface 3 toward the heat pipe side surface 4, the contact area of the fixing portion 41 with the base plate 2 increases and the cooling performance is improved. Further, since the thickness of the fixing portion 41 is thin, the temperature distribution of the fixing portion 41 in the thickness direction does not become non-uniform, and heat is efficiently transmitted.

[0049] Since one end of the heat pipe 21 is bent to form a fixed portion 41 and an extension portion 31, the heat pipe 21 of the drive unit 101 is configured such that one extension portion 31 is provided for each fixed portion 41. As a result, the refrigerant is not unevenly distributed compared to the case where multiple extension portions 31 are provided for each fixed portion 41, and the cooling performance of the heat pipe 21 is improved. Furthermore, since the heat pipe 21 according to Embodiment 1 is made by bending, it is easier to manufacture compared to the case where multiple extension portions 31 are provided for each fixed portion 41.

[0050] The drive unit 101 improves its cooling performance by using a cooling fan 60 to guide airflow to multiple heat pipes 21 and multiple fins 50.

[0051] Furthermore, the drive unit 101 includes a ventilation cover 70 that surrounds the multiple heat pipes 21 and the multiple fins 50.

[0052] The drive unit 101 guides airflow with a cooling fan 60, but by further including a ventilation cover 70, it is possible to concentrate the airflow to multiple heat pipes 21 and multiple fins 50.

[0053] The multiple 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) arranged in the direction of airflow, and the extension 31a of the first row, first column heat pipe 21a and the extension 31c of the second row, first column heat pipe 21c do not overlap when viewed from the direction of airflow.

[0054] The drive unit 101 can efficiently deliver air to each extension 31 of the heat pipes 21 by ensuring that the extensions 31 of the heat pipes 21 do not overlap. By arranging the heat pipes 21 alternately in the direction of airflow, the drive unit 101 allows air to flow to the extension 31c of the second row, first column heat pipe 21c, avoiding the extension 31a of the first row, first column heat pipe 21a, thereby efficiently cooling the heat pipes 21. Furthermore, by arranging the heat pipes 21 alternately in the direction of airflow, air can hit the heat pipes 21, disrupting the airflow and improving the cooling performance of the drive unit 101.

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

[0056] The drive unit 101 improves cooling performance because the arrangement of the fixing parts 41 prevents the extensions 31 of the heat pipes 21 from overlapping. Furthermore, because the fixing parts 41 are not unevenly positioned in the width direction, the heat distribution on the base plate 2 is not uneven, allowing for efficient cooling.

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

[0058] In the drive unit 101, a portion of the cooling fan 60 protrudes towards the power device 1, bringing the opening of the cooling fan 60 closer to the base plate 2. This allows the airflow from the cooling fan 60 to reach the portion of the fins 50 closest to the base plate 2, thus cooling the entire fin 50. The drive unit 101 is further equipped with a cooling fan cover 80, which allows for concentrated airflow to be directed to the multiple heat pipes 21 and the multiple fins 50.

[0059] Furthermore, the drive unit 101 has an opening 8 in the base plate 2, and a part of the cooling fan 60 protrudes towards the power device 1 side and is installed in the opening 8, so that the cooling fan 60 can be positioned across the base plate 2 on both the heat pipe 21 side and the power device 1 side. This increases the space for the cooling fan 60, allowing for the placement of a cooling fan 60 with a larger airflow, thereby improving cooling performance. In addition, because a fan with a larger airflow can be placed, the number of fans can be reduced.

[0060] Furthermore, the extension portion 31 of the heat pipe 21 is flattened. Also, the bent portion 51 of the heat pipe 21 is flattened. In other words, the extension portion 31, the fixed portion 41, and the bent portion 51 of the heat pipe 21 are flattened.

[0061] The drive unit 101, with its flattened extension 31, does not obstruct the airflow from the cooling fan 60. This prevents a reduction in the airflow from the cooling fan 60. The drive unit 101 is easy to manufacture because, when producing the flattened extension 31, fixing 41, and bending 51, only the flattened heat pipe 21 needs to be bent.

[0062] The heat pipe 21 has a surface area where the extension portion 31 is larger than the surface area where the fixed portion 41 is larger.

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

[0064] In the first embodiment, the cooling fan 60 is positioned downstream of the heat pipes 21 and fins 50 in the airflow direction. However, if the cooling fan 60 is configured to guide air to the heat pipes 21 and fins 50, it may be positioned upstream of the heat pipes 21 and fins 50 in the airflow direction.

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

[0066] Embodiment 2. Next, Embodiment 2 will be described with reference to Figure 7. The drive device 102 according to Embodiment 2 differs from that of Embodiment 1 in the arrangement of the multiple heat pipes.

[0067] Figure 7 is a cross-sectional view of the drive unit 102 according to Embodiment 2, parallel to the power device side surface 3. Components identical to those in Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted.

[0068] In the drive device 102 according to Embodiment 2, the position of the extension portion 32 relative to the fixing portion 42 of the heat pipe 22 is different. As a result, the multiple heat pipes 22 are arranged so that adjacent extension portions 32 in the ventilation direction do not overlap with each other when viewed from the ventilation direction.

[0069] The arrangement of the multiple heat pipes 22 according to Embodiment 2 will be specifically explained using the heat pipe 22a in the first row and first column, the heat pipe 22b in the first row and second column, the heat pipe 22c in the second row and first column, and the heat pipe 22d in the second row and second column.

[0070] As shown in Figure 7, the multiple heat pipes 22 are arranged in different orientations. In Embodiment 2, the multiple heat pipes 21 are arranged rotated by 180 degrees each. That is, adjacent heat pipes 22 in the ventilation direction are installed inverted. Specifically, the first row, first column heat pipe 22a and the first row, second column heat pipe 22b are arranged such that their extensions 32a and 32b are located to the left of their respective fixed parts 42a and 42b. 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 their extensions 32c and 32d are located to the right of their respective fixed parts 42c and 42d.

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

[0072] The fixing portion 42a of the first row, first column heat pipe 22a and the fixing portion 42c of the second row, first column heat pipe 22c coincide in position in the left-right direction of the drive unit 101. As shown in Figure 7, in the left-right direction of the drive unit 101, the fixing portion 42c of the second row, first column heat pipe 22c is positioned in the same position as the fixing portion 42a of the first row, first column heat pipe 22a. Viewed from the ventilation direction, the fixing portion 42c of the second row, first column heat pipe 22c overlaps with the fixing portion 42a of the first row, first column heat pipe 22a and is arranged in a single row.

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

[0074] Multiple heat pipes 22 can be positioned such that, even if the fixed portion 42 is in the same position when viewed from the ventilation direction, adjacent extensions 32 do not overlap in the ventilation direction, because the positions of the extensions 32 relative to the fixed portion 42 are different.

[0075] Based on the above, in Embodiment 2, an example was shown in which the fixing portions 42 of the multiple heat pipes 22 are arranged in the same position when viewed from the ventilation direction, but the fixing portions 42 may be arranged at different positions.

[0076] As a modification of Embodiment 2, a drive device 103 is described in which the positions of the extensions 33 relative to the fixed portion 43 of the heat pipe 23 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 extensions 33 do not overlap each other when viewed from the ventilation direction. The modification of Embodiment 2 is a combination of Embodiment 1 and Embodiment 2.

[0077] A modified example of Embodiment 2 will be described with reference to Figure 8. Figure 8 is a cross-sectional view of the drive device 103 according to a modified example of Embodiment 2, parallel to the power device side surface 3.

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

[0079] Similar to Embodiment 2, adjacent heat pipes 23 in the ventilation direction are installed in reverse. Focusing on the first row, first column heat pipe 23a and the second row, first column heat pipe 23c, the position of the extension portion 33 relative to the fixed portion 43 is different in the left-right direction of the drive unit 103. As shown in Figure 8, the position of the extension portion 33c relative to the fixed portion 43c in the second row, first column heat pipe 23c is on the opposite side in the left-right direction of the drive unit from the position of the extension portion 33a relative to the fixed portion 43a in the first row, first column heat pipe 23a.

[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 do not coincide in the left-right direction of the drive unit 103. As shown in Figure 8, the fixing portion 43c of the second row, first column heat pipe 22c is positioned 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 fixing portion 43c of the second row, first column heat pipe 23c is to the right of the right end face of the fixing portion 43a of the first row, first column heat pipe 23a. The left end face of the fixing portion 43c is to the left of the left end face of the fixing portion 43a.

[0082] Multiple heat pipes 23 can be arranged in positions where the extensions 33 do not overlap, by having the fixing portions 43 offset from each other and the extensions 33 relative to the fixing portions 43 positioned at different locations.

[0083] In Embodiment 2 and its modified form, the position of the extension portion 33 relative to the fixed portion 43 is different, thus increasing the degree of freedom in arranging the heat pipes 22 and 23 compared to Embodiment 1. As a result, in the left-right direction of the drive units 102 and 103, the distance between the right end faces of the fixed portions 42a and 43a and the right end faces of the fixed portions 42c and 43c may be less than or equal to the thickness of the extension portions 32a and 33a of the first row, first column heat pipes 22a and 23a. In other words, in the left-right direction of the drive units 102 and 103, the distance between the fixed portions 42 and 43 may be less than or equal to the length of the extension portions 32 and 33 of the heat pipes 22 and 23.

[0084] Based on the above, in the drive devices 102 and 103 according to Embodiment 2 and its modifications, the positions of the extensions 32c and 33c relative to the fixing portions 42c and 43c in the second row, first column heat pipes 22c and 23c (second heat pipes) are on the opposite side from the positions of the extensions 32a and 33a relative to the fixing portions 42a and 43a in the first row, first column heat pipes 22a and 23a (first heat pipes).

[0085] Similar to Embodiment 1, the cooling performance of the drive units 102 and 103 is improved. In addition to this effect, the following effects can be observed. Because the positions of the extensions 32 and 33 relative to the fixed portions 42 and 43 of the heat pipes 22 and 23, which are aligned in the direction of airflow, are different, the extensions 32 and 33 of the heat pipes 22 and 23 do not overlap, and air can be efficiently delivered to each extension 32 and 33.

[0086] Furthermore, in Embodiment 2 and its modifications, the positions of the extensions 32 and 33 relative to the fixed parts 42 and 43 are different, resulting in greater flexibility in the arrangement of the fixed parts 42 and 43 compared to Embodiment 1. Also, since the distance between the fixed parts 42 and 43 can be brought closer than in Embodiment 1, the area required for the heat pipes 22 and 23 can be reduced. This allows for a more compact device. In addition, since more heat pipes 22 and 23 can be arranged in a given area, the cooling performance is further improved.

[0087] Embodiment 3. Next, Embodiment 3 will be described with reference to Figures 9 and 10. The drive device 104 according to Embodiment 3 has a different shape in its extension portion compared to Embodiment 1.

[0088] Figure 9 is an external view of the heat pipe 24 according to Embodiment 3. Figure 10 is a cross-sectional view of the drive device 104 according to Embodiment 3, perpendicular to the direction in which the fins 50 are arranged. Figure 10 is a cross-sectional view taken in the -z direction. Components identical to those in Embodiments 1 and 2 are denoted by the same reference numerals and their descriptions are omitted.

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

[0090] The fin 50 has a cylindrical hole through which a cylindrical extension 34 passes, and the heat pipe 24 is inserted. Note that the cylindrical shape does not have to be a perfect circle in cross-section; it may be an ellipse or other shape.

[0091] Similar to Embodiment 1, the heat pipes 24 are arranged such that, when viewed from the ventilation direction, adjacent extensions 34 in the ventilation direction do not overlap.

[0092] Based on the above, in the drive device 104 according to Embodiment 3, 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 is cylindrical in shape.

[0093] Similar to Embodiment 1, the cooling performance of the drive unit 104 is improved. In addition to this effect, the following effects can be obtained: Because the extension portion 34 of the heat pipe 24 has a shape different from the flattened shape, the processing accuracy of the bending process can be relaxed. Furthermore, because the extension portion 34 of the heat pipe 21 has a cylindrical shape, it is easier to attach it to the fin 50. As a result, the mass production capability of the drive unit 104 is also improved.

[0094] The configurations shown in the embodiments described above are merely examples of the content of this disclosure, and it is possible to combine technologies from different embodiments or with other known technologies. Furthermore, it is possible to omit or modify parts of the configuration without departing from the gist of this disclosure.

[0095] 101, 102, 103, 104 Drive unit, 1 Power device, 2 Base plate, 3 Side surface of power device, 4 Side surface of heat pipe, 8 Opening, 10 Control unit, 20 Cooler, 21, 22, 23, 24 Heat pipes, 21a, 22a, 23a Heat pipes in the first row, 1st column, 21b, 22b, 23b Heat pipes in the first row, 21c, 22c, 23c Heat pipes in the first row, 1st column, 21d, 22d, 23d Heat pipes in the second row, 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 Bent section, 60 Cooling fan, 70 Ventilation cover, 71 Ventilation hole, 80 Cooling fan cover.

Claims

1. A drive device comprising: 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 having an extension portion extending in a direction toward the second surface, a fixing portion extending in a direction different from the direction in which the extension portion extends and fixed to the base plate, and a curved portion provided between the extension portion and the fixing portion; a plurality of fins into which the plurality of heat pipes are inserted; and a cooling fan for inducing airflow to the plurality of heat pipes and the plurality of fins, wherein the fixing portion has a flattened shape, and the fixing portion is arranged such that the thickness direction of the fixing portion is toward the direction toward the second surface.

2. The drive device according to claim 1, characterized in that the direction in which the cooling fan directs airflow is the ventilation direction, the plurality of heat pipes have a first heat pipe and a second heat pipe arranged in the ventilation direction, and the extension portion of the first heat pipe and the extension portion of the second heat pipe do not overlap when viewed from the ventilation direction.

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

4. The drive device according to claim 2 or 3, characterized in that the position of the extension portion relative to the fixed portion in the second heat pipe is on the opposite side to the position of the extension portion relative to the fixed portion in the first heat pipe.

5. The drive device according to any one of claims 1 to 4, wherein the base plate has an opening that penetrates in a direction from the first surface to the second surface, and the cooling fan has a portion that protrudes toward the power device side and is provided in the opening, and includes a fan cover that surrounds the cooling fan on the power device side.

6. The drive device according to any one of claims 1 to 5, characterized in that the extension portion of the heat pipe is flattened.

7. The drive device according to any one of claims 1 to 5, characterized in that the extension portion of the heat pipe has a different shape from the fixed portion.

8. The drive device according to claim 7, characterized in that the extension portion of the heat pipe is cylindrical.

9. The drive device according to any one of claims 1 to 8, characterized in that the surface area of ​​the extension portion of the heat pipe is larger than the surface area of ​​the fixed portion.

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