ELECTRIC COMPRESSOR DEVICE

Abstract

This electric compressor device comprises a motor housing that accommodates a motor. Within the motor housing, a cooling flow path is formed through which a coolant flows circumferentially and radially outside the motor stator. When viewed along the circumferential direction, the axial length of the cooling flow path is at least twice its radial length. At least one rib is provided in the motor housing, projecting radially outward from an inner circumferential wall surface beneath the wall surfaces of the motor housing that define the cooling flow path and extending circumferentially.

Description

Technical field

[0001] The present disclosure relates to an electric compressor device. State of the art

[0002] An electric compressor device is known in the prior art, which is provided with a motor housing in which a flow channel for a coolant is formed. The coolant flowing through the flow channel cools a stator or the like of a motor that forms the electric compressor device. For example, a coolant channel extending in a circumferential direction is formed in a motor housing according to PTL 1. List of citations from patent literature

[0003] [PTL 1] Japanese unexamined patent application publication no. 2015-209845 Summary of the invention: Technical problem

[0004] However, the cross-section of the coolant channel in the engine housing has an essentially square shape. This tends to reduce the coolant flow velocity. Consequently, the electric compressor may not be able to provide sufficient cooling capacity.

[0005] One objective of the present disclosure is to provide an electric compressor device with improved cooling performance. Solution to the problem

[0006] An electric compressor device according to at least one embodiment of the present disclosure comprises a rotating shaft, a compressor wheel provided on the rotating shaft, a motor for driving the rotating shaft, and a motor housing that accommodates the motor, wherein the motor includes a rotor attached to the rotating shaft and a stator arranged around the rotor and supported by the motor housing, wherein a cooling flow channel, which causes a coolant to flow along a circumferential direction, is formed on an outer surface in a radial direction with respect to the stator, wherein, in a view along the circumferential direction, the length of the cooling flow channel in an axial direction is twice or more than the length of the cooling flow channel in a radial direction, and at least one rib extending from an inner radial side wall surface of a wall surface of the motor housing that defines the cooling flow channel,which projects radially towards the outside and extends in the circumferential direction. Advantageous effects of the invention

[0007] According to the present disclosure, an electric compressor device with improved cooling performance can be provided. Brief description of the drawings Fig. Figure 1 is a schematic cross-sectional view of an electric compressor device according to one embodiment. Fig. 2 is a partially enlarged view of Fig. 1. Fig. Figure 3 is a schematic graph showing a relationship between a flow rate and a heat transfer coefficient of a cooling fluid specified by simulation. Fig. 4A is a schematic cross-sectional view of a first rib 71 forming a rib 70 (a first example). Fig. 4B is a schematic cross-sectional view of the first rib 71, which forms rib 70 (a second example). Fig. Figure 5 is a schematic view of a motor housing in a view along an axial direction according to one embodiment. Fig. Figure 6A is a schematic cross-sectional view representing a motor housing according to a first embodiment. Fig. Figure 6B is a schematic cross-sectional view showing a motor housing according to a second embodiment. Fig. Figure 6C is a schematic cross-sectional view representing a motor housing according to a third embodiment. Fig. Figure 6D is a schematic cross-sectional view representing a motor housing according to a fourth embodiment. Description of embodiments

[0008] Some embodiments of the present disclosure are described below with reference to the accompanying drawings. Dimensions, materials, shapes, relative arrangements, and the like of components described as embodiments or illustrated in the drawings are not intended to limit the scope of protection of the present disclosure and are merely simple descriptive examples.

[0009] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "perpendicular", "center", "concentric" or "coaxial", which represent relative or absolute arrangement, do not only represent such an arrangement in a strict sense, but also a state of relative displacement with tolerance or with an angle or distance with which the same function is obtained.

[0010] For example, expressions such as "identical", "equal" and "homogeneous", which represent a state of equality between objects, do not only represent a state of equality in the strict sense, but also a state in which tolerance or a difference exists that preserves the same function.

[0011] For example, expressions that represent shapes, such as a square shape and a cylindrical shape, do not only represent shapes, such as a square shape and a cylindrical shape, in a strictly geometric sense, but also shapes that include a rough section, a chamfered section, and the like, with which the same effect is achieved.

[0012] However, expressions such as "provided with", "contain" or "exhibit" of one component are not exclusive expressions that exclude the presence of other components.

[0013] The same configurations can be designated by the same reference symbols, and descriptions of them cannot be repeated. <Gesamtkonfiguration von elektrischer Kompressorvorrichtung 1>

[0014] Fig. Figure 1 is a schematic cross-sectional view of an electric compressor device 1 according to an embodiment of the present disclosure. The electric compressor device 1 of the present example is a two-stage compression electric compressor equipped with a rotating shaft 2. For example, the two-stage compression electric compressor is configured to supply compressed air to a fuel cell mounted in a vehicle.

[0015] In the following description, a direction in which an axis of the rotating shaft 2 extends can be referred to as an "axial direction," and a circumferential direction and a radial direction with respect to the axis can simply be referred to as a "circumferential direction" and a "radial direction," respectively. An outside in the radial direction is a side in a direction away from the axis of the rotating shaft 2, and an inside in the radial direction is a side in a direction close to the axis.

[0016] The electric compressor device 1 is provided with a housing 20 that accommodates the rotating shaft 2. The housing 20 comprises a low-pressure-side housing 23, which accommodates a low-pressure gear 13 provided at one end section of the rotating shaft 2; a high-pressure-side housing 24, which accommodates a high-pressure gear 14 provided at the other end section of the rotating shaft 2; and a motor housing 25, which accommodates a motor 5 for driving the rotating shaft 2. In the present embodiment, the low-pressure-side housing 23 and the high-pressure-side housing 24 are arranged such that the motor housing 25 is inserted axially between them.

[0017] An inlet port 236, a diffuser 237, a screw section 238, and a discharge port (not shown) are formed in the low-pressure housing 23. Similarly, an inlet port 246, a diffuser 247, a screw section 248, and a discharge port (not shown) are formed in the high-pressure housing 24. The discharge port of the low-pressure housing 23 is connected to the inlet port 246 of the high-pressure housing 24 via a connecting pipe (not shown). The low-pressure housing 23 and the low-pressure impeller 13 function as a low-pressure stage compressor 3, and the high-pressure housing 24 and the high-pressure impeller 14 function as a high-pressure stage compressor 4. The low-pressure impeller 13 and the high-pressure impeller 14 are each examples of compressor impellers.

[0018] The motor 5 comprises a rotor 51, which is attached to the rotating shaft 2 between the high-pressure stage wheel 14 and the low-pressure stage wheel 13, and a stator 52, which is arranged around the rotor 51. The rotor 51 includes a rotor core, which is supported by the rotating shaft 2, and several permanent magnets, which are supported by the rotor. The stator 52 comprises a stator core 53, which extends in the circumferential direction, and a stator coil 54, which is provided in the stator core 53. The stator core 53 is supported by the motor housing 25.

[0019] An operating overview of the electric compressor device 1 is described below. A current flowing through the stator coil 54 forms a rotating magnetic field, and the rotor 51 begins to rotate together with the rotating shaft 2. Accordingly, the low-pressure stage wheel 13 and the high-pressure stage wheel 14 also begin to rotate. Air enters the low-pressure stage compressor 3 from the inlet port 236 (arrow A1). The incoming air is accelerated by the centrifugal force of the low-pressure stage wheel 13. The accelerated air is slowed down and pressurized by the diffuser 237 and then flows through the screw section 238 and is discharged from the outlet port (arrow A2). The low-pressure air compressed by the low-pressure stage compressor 3 is conveyed through the connecting pipe (arrow A3) to the inlet port 246.In the high-pressure stage compressor 4, the low-pressure air that has passed through the inlet port 246 is accelerated by the centrifugal force of the high-pressure stage wheel 14. The accelerated air is slowed down and pressurized by the diffuser 247 and then flows through the screw section 248 and is discharged from the discharge port (arrow A4).

[0020] While the electric compressor device 1 performs the above operation, a current flows through the stator coil 54. This increases the temperature of the stator 52. The temperature of the stator 52 is also increased by an eddy current generated in at least one of the stator cores 53 and the stator coil 54. Therefore, in the motor housing 25 of the present example, a cooling flow channel 40 is formed on the outside in the radial direction with respect to the stator 52 to cause a cooling fluid (not shown) to flow along the circumferential direction. <Overview of cooling flow channel 40>

[0021] The cooling flow channel 40 according to an embodiment of the present disclosure is described with reference to Fig. 1 and Fig. 2 described. Fig. 2 is a partially enlarged view of Fig. 1. The cooling flow channel 40 of the present example contains a first cooling flow channel 41, a second cooling flow channel 42, and a first return cooling flow channel 46. The first cooling flow channel 41 and the second cooling flow channel 42 extend circumferentially and are arranged axially. The first return cooling flow channel 46 communicates with the first cooling flow channel 41 and the second cooling flow channel 42. The coolant, having passed through an inlet 251 formed in the engine housing 25, flows into the first cooling flow channel 41 (arrow B1). The coolant flows through the first cooling flow channel 41, the first return cooling flow channel 46, and the second cooling flow channel 42 in that order and is discharged from an outlet 252 formed in the engine housing 25 (arrow B2).

[0022] A cross-sectional shape of the cooling flow channel 40 is described. In the cooling flow channel 40 of the present example, when viewed along the circumferential direction, the axial length of the cooling flow channel 40 is greater by a factor of two or more, and more specifically four or more, than the radial length of the cooling flow channel 40. If a ratio of the length in the axial direction to the length in the radial direction is defined as an aspect ratio, a length in the axial direction that is greater than the length in the radial direction by a factor of N or more is equivalent to an aspect ratio of 1 / N or less. That is to say, the aspect ratio of the cooling flow channel 40 of the present example is 0.5 or less, and more specifically 0.25 or less.

[0023] The aspect ratio of 0.25 or less can be specified for at least one flow channel extending in the circumferential direction, specifically for cooling flow channel 40. That is, in the examples in Fig. 1 and Fig. 2. The aspect ratios of the first cooling flow channel 41 and the second cooling flow channel 42 can be 0.25 or less. The axial length and radial length of the first cooling flow channel 41 correspond to dimensions La and Ld, respectively. Fig. 2. The axial length and the radial length of the second cooling flow channel 42 correspond to dimensions Ma and Md, respectively. In a case where the aspect ratio of the cooling flow channel 40 is 0.25 or less, dimension La is four times or more larger than dimension Ld, and dimension Ma is four times or more larger than dimension Md.

[0024] In the present example, the cross-sectional area of ​​the first returning cooling flow channel 46 has the same shape. Furthermore, in a view along the axial direction, the length of the first returning cooling flow channel 46 in the circumferential direction is two or more times greater, and more specifically four or more times greater (not shown), than the length of the first returning cooling flow channel 46 in the radial direction.

[0025] As in Fig. As shown in Figure 2, the motor housing 25 includes at least one rib 70 extending circumferentially along the cooling flow channel 40. In particular, the motor housing 25 includes a wall surface 60 defining the cooling flow channel 40, and the wall surface 60 comprises an inner radial side wall surface 62 and an outer radial side wall surface 64. The rib 70 projects radially from the inner radial side wall surface 62 to the outer surface. The rib 70 is a projecting surface configured to be integrated with the inner radial side wall surface 62. By providing the rib 70 on the inner radial side wall surface 62 instead of the outer radial side wall surface 64, the stator core 53, whose temperature is likely to increase, can be effectively cooled. The rib 70 can also be provided on the outer radial side wall surface 64.

[0026] While the rib 70 is not an essential element of the present disclosure, several ribs 70 are arranged at intervals in the axial direction according to the present embodiment. As a more specific example, the rib 70 includes several first ribs 71 arranged at intervals in the axial direction in the first cooling flow channel 41, and several second ribs 72 arranged at intervals in the axial direction in the second cooling flow channel 42. Each first rib 71 and each second rib 72 extend in the circumferential direction.

[0027] The number of fins 70 provided in the circumferential cooling flow channel 40 can be two or more, or three or more. In the example shown, the number of first fins 71 arranged in the first cooling flow channel 41 is three, and the number of second fins 72 arranged in the second cooling flow channel 42 is also three. As described in detail later, the fin 70 may or may not be arranged in the first return cooling flow channel 46 (see Figure 1). Fig. 6A and Fig. 6B).

[0028] According to the configuration above, since the aspect ratio of the cooling flow channel 40 is less than 1, the flow velocity of the coolant in the cooling flow channel 40 is increased. Furthermore, the cross-sectional area of ​​the flow channel is suitably reduced by providing at least one fin 70. This further increases the flow velocity of the coolant. Consequently, the heat transfer coefficient between the cooling flow channel 40 and the coolant is increased. The heat transfer area is also increased by providing the fin 70. Thus, the electric compressor device 1 is implemented with improved cooling performance. Moreover, by using a configuration in which the multiple fins 70 are arranged at intervals in the axial direction, the heat transfer area is further increased, and the cooling performance of the electric compressor device 1 is further improved.

[0029] In the present embodiment, the flow velocity of the coolant is increased by adjusting the aspect ratio to 1 or less. This also allows the flow rate of the coolant to be reduced. Fig. Figure 3 is a schematic graph showing the relationship between the flow rate and the heat transfer coefficient of the cooling fluid, which is specified by analysis. In the graph in Fig. Figure 3 shows a solid line representing the cooling flow channel 40 according to an example with an aspect ratio of 0.25, and a dashed line represents a cooling flow channel (not shown) according to a comparison example with an aspect ratio of 1. As described above, the heat transfer coefficient of the cooling flow channel 40 is increased compared to the heat transfer coefficient of the cooling flow channel according to the comparison example. Consequently, the flow rate of the coolant required to implement a heat transfer coefficient (E shown in the graph) necessary for the electric compressor device 1 is lower for the cooling flow channel 40 according to the example than for the cooling flow channel according to the comparison example. Accordingly, the flow rate of the coolant flowing through the cooling flow channel 40 can also be reduced for the electric compressor device 1.

[0030] The cooling flow channel 40 according to another example can be configured with only the first cooling flow channel 41, without including the second cooling flow channel 42 and the first return cooling flow channel 46. Furthermore, only one first fin 71 can be provided for the first cooling flow channel 41. These embodiments also achieve the above-mentioned technical advantages. <Rippe 70 Gemäß mehreren Ausführungsformen>

[0031] Fig. 4A and Fig. Figure 4B shows the first rib 71, which forms rib 70. Fig. 4A is a schematic cross-sectional view of a first rib 71A (71), and Fig. Figure 4B is a schematic cross-sectional view of a first rib 71B (71). At least one of the configurations relating to the first ribs 71A and 71B described below can be applied to the second rib 72 (see Figure 4B). Fig. 2).

[0032] As in Fig. 4A and Fig. As shown in Figure 4B, the maximum lengths (one dimension h) of the first fins 71A and 71B (71) in the radial direction are 4 / 5 or less, and more preferably 2 / 3 or less, of the maximum length (one dimension H) of the first cooling flow channel 41 in the radial direction. Any value can be used as the minimum value of dimension h. For example, dimension h can be 1 / 5 or more, and more specifically 2 / 5 or more, of dimension H.

[0033] According to the above configuration, a decrease in the flow rate of the coolant due to an excessively narrow space between the outer radial side wall surface 64 of the motor housing 25 and the first fins 71A and 71B can be avoided, and an increase in the flow velocity of the coolant and a subsequent increase in a pressure loss locally generated in the first cooling flow channel 41 can be avoided.

[0034] The above relationship between dimension h and dimension H can also be established between the second rib 72 and the second cooling flow channel 42. Furthermore, in particular, the radial lengths of the first rib 71 and the first cooling flow channel 41 and the radial lengths of the second rib 72 and the second cooling flow channel 42 can be equal. As a more detailed example, the first rib 71 and the second rib 72 can have the same shape when viewed along the circumferential direction, and the first cooling flow channel 41 and the second cooling flow channel 42 can have the same shape when viewed along the circumferential direction.

[0035] The in Fig. 4A and Fig. The multiple first ribs 71A and 71B (71) shown in Figure 4B each contain tip sections 175A and 175B (175), which are outer ends in the radial direction. Tip section 175 is a flat surface of the first rib 71 facing the outer surface in the radial direction and is a flat surface perpendicular to the radial direction. Lengths of tip sections 175A and 175B in the axial direction correspond to dimension Wt. An interval (the shortest distance in the axial direction) between two adjacent first ribs 71A and 71B in the axial direction among the multiple first ribs 71A and 71B (71) corresponds to dimension Ws. In the present example, dimension Ws is larger than dimension Wt. In other words, the first several ribs 71 are arranged in the axial direction at intervals greater than the length of the tip section 175 in the axial direction. The dimension Wt can be smaller or larger than the dimension h.

[0036] According to the configuration above, an excessive increase in the flow velocity of the cooling fluid and a subsequent increase in pressure loss due to an excessively small distance between two adjacent first ribs 71 can be avoided. The above relationship between dimension Ws and dimension Wt can also be established for the second rib 72. That is, the multiple second ribs 72 can be arranged in the axial direction at intervals greater than the length of a tip section of the second rib 72 in the axial direction.

[0037] As in Fig. 4A and Fig. As shown in Figure 4B, the wall surface 60 of the motor housing 25 includes a pair of side surfaces 65 facing the axial direction. In both drawings, the shortest distance between one of the several first ribs 71A and 71B (71) closest to the side surface 65 and the side surface 65 is specified by a dimension Wf. The dimension Wf is larger than the dimension Wt mentioned above. In other words, the shortest distance between the first rib 71 closest to the side surface 65 and the side surface 65 is longer than the length of the tip section 175 in the axial direction.

[0038] According to the configuration above, an excessive increase in the flow velocity of the cooling fluid and a subsequent increase in pressure loss due to an excessively short shortest distance between the first fin 71 and the side surface 65 can be avoided. The above relationship between dimension Wf and dimension Wt can also be established for the second fin 72. That is, the shortest distance between a side surface (not shown) of the wall surface 60, which defines the second cooling flow channel 42, and the second fin 72, which is closest to the side surface, can be longer than the length of the tip section of the second fin 72 in the axial direction.

[0039] As in Fig. 4A and Fig. As shown in Figure 4B, in the circumferential view, each of the several first ribs 71A (71) has a trapezoidal shape, and each of the several first ribs 71B (71) has a rectangular shape. In the present example, the first ribs 71A and 71B are connected to the inner radial side wall surface 62 of the wall surface 60 by a curved surface 69. According to the above configuration, for example, the manufacture of the motor housing 25, which can be carried out by casting, can be facilitated. The above configuration of the first rib 71 can be applied to the second rib 72. That is, in the circumferential view, the second rib 72 can have a trapezoidal or a rectangular shape. <Detailliertes Beispiel von Motorgehäuse 25 und Kühlströmungskanal 40>

[0040] Fig. Figure 5 is a schematic view of the motor housing 25 in the axial direction according to an embodiment of the present disclosure. As shown in the drawing, the motor housing 25 comprises a first body end section 81, which is one end section in the circumferential direction, and a second body end section 82, which is the other end section in the circumferential direction. The first body end section 81 and the second body end section 82 face each other in the circumferential direction, with a gap M between them. The motor housing 25 of the present example has a substantially cylindrical shape extending in the axial direction and has a substantially C-shape in the axial direction view.

[0041] Fig. 6A and Fig. Figure 6B shows a motor housing 25A (25) according to a first embodiment and a motor housing 25B (25) according to a second embodiment, respectively. Both drawings show unfolded views of the motor housing 25, and vertical directions in the drawings correspond to the circumferential direction (the same applies to Fig. 6C and Fig. 6D, which are described later). Furthermore, for ease of understanding, the hatching of rib 70 differs from the hatching of motor housing 25 in both drawings (the same applies to Fig. 6C and Fig. 6D, which are described later). A cooling flow channel 40A (40) of the motor housings 25A and 25B (25) contains the first cooling flow channel 41 and the second cooling flow channel 42, which extend in the circumferential direction, and the first return cooling flow channel 46, which communicates with the first cooling flow channel 41 and the second cooling flow channel 42.

[0042] To implement the cooling flow channel 40A described above, a first partition 91 is included in the motor housings 25A and 25B (25). The first partition 91 extends circumferentially to divide the cooling flow channel 40A into the first cooling flow channel 41, the second cooling flow channel 42, and the first return cooling flow channel 46. Furthermore, the first partition 91 includes a first connecting end section 911, which is connected to the first body end section 81; a first flow channel forming end section 912, which faces the second body end section 82 circumferentially, with the first return cooling flow channel 46 inserted between them; and a first extension section 913, which extends circumferentially between the first connecting end section 911 and the first flow channel forming end section 912.The first extension section 913 extends parallel to the first rib 71 and the second rib 72. See the examples in . Fig. 6A and Fig. 6B is a region in which the first cooling flow channel 41 is arranged circumferentially, or a region in which the second cooling flow channel 42 is arranged circumferentially, equivalent to a region in which the first partition 91 is arranged circumferentially. The first return cooling flow channel 46 is arranged at a position that differs from the first partition 91 circumferentially.

[0043] In the Fig. 6A and Fig. In the examples shown in Figure 6B, the inlet 251 is formed in the first cooling flow channel 41, and the outlet 252 is formed in the second cooling flow channel 42. The coolant that has passed through the inlet 251 flows through the first cooling flow channel 41 and then, in this sequence, through the first return cooling flow channel 46 and the second cooling flow channel 42, and is discharged from the outlet 252.

[0044] According to the configuration above, by arranging the first return cooling flow channel 46, the length of the cooling flow channel 40 in the axial direction (in other words, the length of the motor housing 25 in the axial direction) can be increased, and the cooling capacity of the electric compressor device 1 is further improved. Furthermore, by arranging the first return cooling flow channel 46, the coolant is caused to move back and forth in the circumferential direction. Thus, the flow channel length of the cooling flow channel 40 is increased, and the cooling capacity of the electric compressor device 1 is improved.

[0045] As in Fig. As shown in Figure 6A, all ribs 70A (70) according to the first embodiment are arranged such that they deviate from the first returning cooling flow channel 46 in the circumferential direction. In particular, the first rib 71 and the second rib 72 are arranged within a region that deviates from the first returning cooling flow channel 46 in the circumferential direction. In the illustrated example, an end section 711 of the first rib 71 and an end section 721 of the second rib 72 can be arranged in the same position as the end section 912 forming the first flow channel in the circumferential direction. According to the above configuration, the shape of the motor housing 25A can be simplified, and the manufacture of the motor housing 25A can be facilitated.

[0046] As in Fig. As shown in Figure 6B, the rib 70B (70) according to the second embodiment further comprises a first curved rib 77, which is arranged in the first return cooling flow channel 46. The first curved rib 77 is connected to one end section 711 of the first rib 71 and one end section 721 of the second rib 72 and is curved in an arc shape such that it is convex towards the second body end section 82. In the present example, several first curved ribs 77 are arranged, and each first curved rib 77 is connected to one end section 711 of each first rib 71 and one end section 721 of each second rib 72.

[0047] According to the configuration above, the heat transfer surface area of ​​the first return cooling flow channel 46 can be increased, and the cooling capacity of the electric compressor device 1 is further improved. Furthermore, the coolant can flow along the first curved fin 77 in the first return cooling flow channel 46, and the pressure drop of the coolant in the first return cooling flow channel 46 can be reduced. <Detailliertes Beispiel von Motorgehäuse 25 und Kühlströmungskanal 40 gemäß weiteren Ausführungsformen>

[0048] Fig. 6C and Fig. Figure 6D shows a motor housing 25C (25) according to a third embodiment and a motor housing 25D (25) according to a fourth embodiment, respectively. A cooling flow channel 40B (40) of the motor housings 25C and 25D (25) further comprises a third cooling flow channel 43 and a second return cooling flow channel 48, in addition to the first cooling flow channel 41, the second cooling flow channel 42, and the first return cooling flow channel 46. The third cooling flow channel 43 is arranged axially with the first cooling flow channel 41 and the second cooling flow channel 42 and extends circumferentially. The second return cooling flow channel 48 communicates with the second cooling flow channel 42 and the third cooling flow channel 43.The ribs 70C and 70D (70) shown further include, in addition to the first rib 71 and the second rib 72, a third rib 73 which extends circumferentially at the third cooling flow channel 43. In the present example, three third ribs 73 are arranged at intervals in the axial direction at the third cooling flow channel 43.

[0049] The in Fig. 6C and Fig. The motor housings 25C and 25D (25) shown in Figure 6D further comprise a second partition 92. The second partition 92 extends circumferentially to divide the cooling flow channels 40C and 40D (40) into the second cooling flow channel 42 and the third cooling flow channel 43. In particular, the second partition 92 further comprises a second connecting end section 921, which is connected to the second body end section 82; a second flow channel-forming end section 922, which faces the first body end section 81 circumferentially, with the second return cooling flow channel 48 inserted between them; and a second extension section 923, which extends circumferentially between the second connecting end section 921 and the second flow channel-forming end section 922. The second extension section 923 extends parallel to the second rib 72 and the third rib 73.

[0050] In the examples in Fig. 6C and Fig. In 6D, the second returning cooling flow channel 48 is arranged at a position that differs from the second rib 72 and the third rib 73 in the circumferential direction. The lengths of the first rib 71 and the third rib 73 in the circumferential direction are equal, and the length of the second rib 72 in the circumferential direction is shorter than the lengths of the first rib 71 and the third rib 73 in the circumferential direction. In the examples in both drawings, the lengths of the first cooling flow channel 41 and the third cooling flow channel 43 in the circumferential direction are equal, and the length of the second cooling flow channel 42 in the circumferential direction is shorter than the lengths of the first cooling flow channel 41 and the third cooling flow channel 43 in the circumferential direction.The circumferential length and the axial length of the second returning cooling flow channel 48 are correspondingly equal to the circumferential length and the axial length of the first cooling flow channel 41.

[0051] In the Fig. 6C and Fig. In the engine housings 25C and 25D shown in Figure 6D (25), the inlet 251 is formed in the first cooling flow channel 41, and the outlet 252 is formed in the third cooling flow channel 43. The coolant that has passed through the inlet 251 flows through the first cooling flow channel 41, the first return cooling flow channel 46, the second cooling flow channel 42, the second return cooling flow channel 48, and the third cooling flow channel 43 in that order and is discharged from the outlet 252.

[0052] According to the configuration above, by adding the second return cooling flow channel 48 in addition to the first return cooling flow channel 46, the length of the cooling flow channel 40 in the axial direction (in other words, the length of the motor housing 25 in the axial direction) can be increased, and the cooling capacity of the electric compressor device 1 is further improved. Furthermore, by adding another second return cooling flow channel 48, the number of times the coolant moves back and forth in the circumferential direction is increased. Thus, the flow channel length of the cooling flow channel 40 is increased, and the cooling capacity of the electric compressor device 1 is improved.

[0053] At the in Fig. In the rib 70C (70) shown in Figure 6C, the second rib 72 and the third rib 73 are arranged within a region that deviates circumferentially from the second returning cooling flow channel 48. The other end section 722 of the second rib 72 and an end section 731 of the third rib 73 can be arranged in the same position circumferentially as the end section 922 forming the second flow channel. According to the above configuration, the shape of the motor housing 25C can be simplified, and the manufacture of the motor housing 25C can be facilitated.

[0054] The in Fig. The rib 70D (70) shown in Figure 6D further comprises a second curved rib 78, which is arranged in the second returning cooling flow channel 48. The second curved rib 78 is connected to the other end section 722 of the second rib 72 and to one end section 731 of the third rib 73 and is curved in an arc shape such that it is convex towards the first body end section 81. In the present example, several second curved ribs 78 are arranged, and every second curved rib 78 is connected to the other end section 722 of every second rib 72 and to one end section 731 of every third rib 73.

[0055] According to the configuration above, the heat transfer surface area of ​​the second return cooling flow channel 48 can be increased, and the cooling capacity of the electric compressor device 1 is further improved. Furthermore, the coolant can flow along the second curved fin 78 in the second return cooling flow channel 48, and the pressure drop of the coolant in the second return cooling flow channel 48 can be reduced. <Andere Modifikationsbeispiele>

[0056] The electric compressor device 1 is not on the in Fig. Figure 1 shows an electric compressor with two-stage compression. The electric compressor device 1 can be an electric compressor with single-stage compression that is installed in a turbocharger device.

[0057] The radial length of the first curved rib 77 can be less than at least the length of the first rib 71 and the radial length of the second rib 72. In this case, the coolant flowing along the first curved rib 77 in the first return cooling flow channel 46 can flow over the first curved rib 77. This reduces the pressure loss in the first return cooling flow channel 46.

[0058] The first curved rib 77 is not limited to extending continuously between one end section 711 of the first rib 71 and one end section 721 of the second rib 72. A first through-hole penetrating the first curved rib 77 in the circumferential direction may be formed in the first curved rib 77. For example, the first curved rib 77 may include a first connecting curved rib extending in an arc from one end section 711 and a second connecting curved rib extending in an arc from one end section 721, and a gap, such as the first through-hole, may be formed between the first connecting curved rib and the second connecting curved rib. The first connected curved rib and the second connected curved rib have radii of the same curvature.In this case, the coolant flowing through the first return cooling flow channel 46 can also pass through the gap, and heat transfer in the first return cooling flow channel 46 can be improved compared to that in a case where the flow of the coolant along the circumferential direction is restricted by the first curved fin 77.

[0059] Similarly, the second curved rib 78 is not limited to extending continuously between the other end section 722 of the second rib 72 and the one end section 731 of the third rib 73. A second through-hole penetrating the second curved rib 78 in the circumferential direction may be formed in the second curved rib 78. For example, the second curved rib 78 may include a third connecting curved rib extending in an arc from the other end section 722 and a fourth connecting curved rib extending in an arc from the one end section 731, and a gap, such as the second through-hole, may be formed between the third connecting curved rib and the fourth connecting curved rib. The third connecting curved rib and the fourth connecting curved rib have radii of the same curvature.In this case, the coolant flowing through the second return cooling flow channel 48 can also pass through the gap, and heat transfer in the second return cooling flow channel 48 can be improved compared to that in a case where the flow of the coolant along the circumferential direction is restricted by the second curved fin 78. <zusammenfassung>

[0060] For example, the above contents are understood as follows according to several embodiments.

[0061] 1) An electric compressor device (1) according to at least one embodiment of the present disclosure comprises a rotating shaft (2), a compressor wheel (at least one of the low-pressure stage wheel 13 and the high-pressure stage wheel 14) provided on the rotating shaft, a motor (5) for driving the rotating shaft and a motor housing (25) that accommodates the motor, wherein the motor includes a rotor (51) attached to the rotating shaft and a stator (52) arranged around the rotor and supported by the motor housing, wherein a cooling flow channel (40) causing a cooling fluid to flow along a circumferential direction is formed on an outer surface in a radial direction with respect to the stator in the motor housing,in a view along the circumferential direction, the length of the cooling flow channel in an axial direction exceeds twice or more the length of the cooling flow channel in a radial direction, and at least one rib (70) is provided, projecting radially from an inner radial side wall surface (62) of a wall surface (60) of the motor housing defining the cooling flow channel to the outside and extending circumferentially.

[0062] According to the configuration described in 1), since the aspect ratio of the cooling channel is less than 1, the flow velocity of the coolant in the cooling channel is increased. Furthermore, the heat transfer surface is appropriately enlarged by incorporating at least one fin. This further increases the flow velocity of the coolant. Consequently, the heat transfer coefficient between the cooling channel and the coolant is increased. The heat transfer surface is also enlarged by the fin. Thus, the electric compressor device is implemented with improved cooling performance.

[0063] 2) In several embodiments of the electric compressor device according to 1), the radial direction length of the rib is 4 / 5 or less of the maximum radial direction length of the cooling flow channel.

[0064] According to the configuration above in 2), a decrease in the flow rate of the cooling fluid due to an excessively narrow cooling flow channel because of the fin can be avoided, and an increase in the flow velocity of the cooling fluid and a subsequent increase in a pressure loss locally generated in the cooling flow channel can be avoided.

[0065] 3) In several embodiments, in the electric compressor device according to 1) or 2), the at least one rib is arranged at several evenly distributed intervals in the axial direction.

[0066] According to the configuration described in 3) above, the heat transfer surface area is further increased. This further improves the cooling performance of the electric compressor device.

[0067] 4) In several embodiments of the electric compressor device according to 3), each of several ribs includes a tip section (175) which is an outer end in the radial direction, and the several ribs are arranged in the axial direction at intervals greater than a length of the tip section in the axial direction.

[0068] According to the configuration described in 4) above, an excessive increase in the flow velocity of the cooling fluid and a subsequent increase in pressure loss due to an excessively small distance between two adjacent fins can be avoided.

[0069] 5) In several embodiments of the electric compressor device according to 4), each of the several ribs has a trapezoidal shape or a rectangular shape when viewed along the circumferential direction.

[0070] According to the configuration described in 5) above, manufacturing the motor housing can be facilitated.

[0071] 6) In several embodiments, in the electric compressor device according to one of 3) to 5), each of several of the ribs includes a tip section (175) which is an outer end in the radial direction, the wall surface of the motor housing is a surface facing the axial direction and includes a side surface (65) which defines the cooling flow channel, and a distance between the rib that is closest to the side surface and the side surface is longer than a length of the tip section in the axial direction.

[0072] According to the configuration described in 6) above, an excessive increase in the flow velocity of the cooling fluid and a subsequent increase in pressure loss due to an excessively short distance between the fin and the side surface can be avoided.

[0073] 7) In several embodiments, in the electric compressor device according to one of 3) to 6), the number of ribs arranged in the cooling flow channel extending in the circumferential direction is three or more.

[0074] According to the configuration described in section 7 above, the heat transfer surface area is further increased. This further improves the cooling performance of the electric compressor device.

[0075] 8) In several embodiments, in the electric compressor device according to one of 1) to 7), the motor housing comprises a first body end section (81) which is an end section in the circumferential direction, a second body end section (82) which is the other end section in the circumferential direction and which faces the first body end section with a gap (M) between the first body end section and the second body end section, and a first partition (91) which extends in the circumferential direction to divide the cooling flow channel into a first cooling flow channel (41) and a second cooling flow channel (42) which are arranged in the axial direction, and a first return cooling flow channel (46) which communicates with the first cooling flow channel and the second cooling flow channel, and the first partition includes a first connecting end section (911) which is connected to the first body end section.and a first flow channel forming end section (912) which faces the second body end section in the circumferential direction, wherein the first returning cooling flow channel is inserted between the second body end section and the end section forming the first flow channel.

[0076] According to the configuration described in 8) above, by providing the first return cooling flow channel in the cooling flow channel, the length of the cooling flow channel in the axial direction can be increased, and the cooling performance of the electric compressor device is further improved.

[0077] 9) In several embodiments, the electric compressor device according to 8) has at least one rib, and all of the ribs are arranged so that they deviate from the first returning cooling flow channel in the circumferential direction.

[0078] According to the configuration described in 9 above, manufacturing the engine housing can be facilitated.

[0079] 10) In several embodiments, in the electric compressor device according to 8), the at least one rib comprises a first rib (71) extending circumferentially in the first cooling flow channel, a second rib (72) extending circumferentially in the second cooling flow channel, and a curved rib (the first curved rib 77) curved in such a way that it is convex to the second body end section in the first returning cooling flow channel, and which is connected to an end section (711) of the first rib and an end section (721) of the second rib.

[0080] According to the configuration described in Figure 10 above, the heat transfer surface area of ​​the first return cooling flow channel can be increased. This further improves the cooling performance of the electric compressor device. Furthermore, the coolant can flow along the curved fin in the first return cooling flow channel, reducing the coolant pressure drop within that channel.

[0081] 11) In several embodiments, in the electric compressor device according to one of 8) to 10), the motor housing further comprises a second partition (92) extending in the circumferential direction to divide the cooling flow channel into the second cooling flow channel and a third cooling flow channel (43) arranged in the axial direction, and a second return cooling flow channel (48) communicating with the second cooling flow channel and the third cooling flow channel, and the second partition comprises a second connecting end section (921) connected to the second body end section, and a second flow channel forming end section (922) facing the first body end section in the circumferential direction, the second return cooling flow channel being inserted between the first body end section and the second flow channel forming end section.

[0082] According to the configuration described in 11 above, by further providing the second return cooling flow channel in the cooling flow channel, the length of the cooling flow channel in the axial direction can be further increased, and the cooling performance of the electric compressor device will be further improved. Reference symbol list 1 electric compressor device 2. Rotating shaft 3 low-pressure stage compressor 4-stage high-pressure compressor 5 engine 13 Low-pressure stage wheel 14 high-pressure stage wheel 20 cases 23 low-pressure side housing 24 high-pressure side housing 25 Motor housings 40 Cooling flow channel 41 first cooling flow channel 42 second cooling flow channel 43 third cooling flow channel 46 First return cooling flow channel 48 Second return cooling flow channel 51 Rotor 52 Stator 53 Stator core 54 Stator coil 60 wall area 62 Inner radial side wall surface 64 Outer radial side wall surface 65 side area 69 curved surface 70 rib 71 first rib 72 second rib 73 third rib 77 first curved rib 78 second curved rib 81 first end section of the body 82 second end of body 91 first partition wall 92 second partition wall 175 Peak section 236, 246 Inlet connection 237, 247 Diffuser 238, 248 snail section 251 Admission 252 Outlet 711, 721, 731 a final section 722 other end section 911 first connecting end section 912 first flow channel forming end section 913 first extension section 921 second connecting end section 922 second flow channel forming end section 923 second extension section M gap QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2015-209845

[0003] < / zusammenfassung>

Claims

[1] Electric compressor device comprising: a rotating shaft; a compressor wheel that is provided on the rotating shaft; a motor to drive the rotating shaft; and a motor housing that accommodates the motor, the engine contains: a rotor attached to the rotating shaft, and a stator arranged around the rotor and supported by the motor housing, wherein a cooling flow channel, which causes a coolant to flow along a circumferential direction, is formed on an outer side in a radial direction with respect to the stator in the motor housing, When viewed along the circumferential direction, the length of the cooling flow channel in an axial direction is two times or more greater than the length of the cooling flow channel in the radial direction, and at least one rib is provided, which projects radially from an inner radial side wall surface of a wall surface of the motor housing, which defines the cooling flow channel, to the outside in the radial direction and which extends in the circumferential direction. [2] Electric compressor device according to claim 1, wherein a radial direction length of the rib is 4 / 5 or less of a maximum radial direction length of the cooling flow channel. [3] Electric compressor device according to claim 1 or 2, wherein the at least one rib is arranged in several at intervals in the axial direction. [4] Electric compressor device according to claim 3, wherein each of several of the ribs includes a tip section which is an outer end in the radial direction, and the multiple ribs are arranged in the axial direction at intervals greater than the length of the tip section in the axial direction. [5] Electric compressor device according to claim 4, wherein, in the view along the circumferential direction, each of the multiple ribs has a trapezoidal shape or a rectangular shape. [6] Electric compressor device according to claim 3, wherein each of several of the ribs includes a tip section which is an outer end in the radial direction, the wall surface of the motor housing is a surface facing the axial direction and includes a side surface that defines the cooling flow channel, and a distance between the rib closest to the side surface and the side surface is longer than a length of the tip section in the axial direction. [7] Electric compressor device according to claim 3, wherein the number of ribs arranged in the cooling flow channel extending in the circumferential direction is three or more. [8] Electric compressor device according to claim 1 or 2, the engine housing contains: a first end section of the body, which is an end section in the circumferential direction, a second body end section, which is the other end section in the circumferential direction and which faces the first body end section with a gap between the first body end section and the second body end section, and a first partition extending in the circumferential direction to divide the cooling flow channel into a first cooling flow channel and a second cooling flow channel arranged in the axial direction, and a first return cooling flow channel communicating with the first cooling flow channel and the second cooling flow channel, and the first partition wall contains: a first connecting end section that is connected to the first body end section, and a first end section forming a flow channel, which is directed towards the second body end section in the circumferential direction, wherein the first returning cooling flow channel is inserted between the second body end section and the end section forming the first flow channel. [9] Electric compressor device according to claim 8, wherein the at least one rib is provided and all ribs are arranged such that they deviate from the first returning cooling flow channel in the circumferential direction. [10] Electric compressor device according to claim 8, wherein the compressor device includes at least one rib: a first rib extending in the circumferential direction at the first cooling flow channel, a second rib extending circumferentially along the second cooling flow channel, and a curved rib that is curved in such a way that it is convex towards the second body end section at the first returning cooling flow channel and is connected to an end section of the first rib and an end section of the second rib. [11] Electric compressor device according to claim 8, the engine housing further contains: a second partition extending in the circumferential direction to divide the cooling flow channel into the second cooling flow channel and a third cooling flow channel arranged in the axial direction, and a second return cooling flow channel communicating with the second cooling flow channel and the third cooling flow channel, and the second partition wall contains: a second connecting end section that is connected to the second body end section, and a second end section forming a flow channel, which is directed towards the first body end section in the circumferential direction, wherein the second returning cooling flow channel is inserted between the first body end section and the end section forming the second flow channel.

Images