Inverter integrated motor

Abstract

The objective of this invention is to provide an inverter-integrated motor that combines improved cooling performance of the current sensor with overall miniaturization of the device. The inverter-integrated motor comprises: a power module that converts direct current into alternating current; a flow path forming body that is formed such that refrigerant flows through the power module and covers the power module; an inverter that internally houses the power module and the flow path forming body; a current sensor that detects alternating current; and a motor that houses the stator and rotor. The power module is positioned opposite the rotation axis of the motor, separated from the stator and rotor. When viewed from the vertical direction of the rotation axis, the current sensor (13) is positioned between the flow path forming body and the coil end of the stator, and at least a portion of the current sensor is housed within the motor housing.

Description

Technical Field

[0001] This invention relates to an inverter-integrated motor. Background Technology

[0002] In inverter-integrated motors, where the motor and inverter are combined, the increasing interior space and driving range of electric vehicles (EVs) further intensifies the demand for miniaturization and thinning. At this point, the increased heat density due to miniaturization necessitates cooling inverter components with low heat resistance. Furthermore, the thinning of the device makes the motor mounting capability of the inverter a challenge, requiring an inverter structure with minimal protrusions to accommodate the increasingly miniaturized motor.

[0003] As background technology for this application, the following patent document 1 is known. In patent document 1, a circuit device is disclosed that can suppress overall enlargement by embedding a current sensor 304 in the intermediate component 3 of the rotary motor 1.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent document 1: Japanese Patent Application Publication No. 2011-250645. Summary of the Invention

[0007] The problem the invention aims to solve

[0008] In the technology of Patent Document 1, if the current sensor 304 is housed within the motor housing without a cooling mechanism, sensing errors occur within the current sensor 304, resulting in poor reliability. Therefore, the objective of this invention is to achieve miniaturization of the inverter-integrated motor while considering the cooling of the current sensor.

[0009] Technical means to solve the problem

[0010] The inverter-integrated motor of the present invention comprises: a power module that converts direct current into alternating current; a flow path forming body that is formed such that a refrigerant flows through the power module and covers the power module; an inverter that internally houses the power module and the flow path forming body; a current sensor that detects the alternating current; a motor having a stator and a rotor; and a motor housing that houses the stator and the rotor. The power module is disposed at a position opposite to the rotation axis of the motor, separated from the stator and the rotor. When viewed from the perpendicular direction of the rotation axis, the current sensor is disposed between the flow path forming body and the coil end of the stator, and at least a portion of the current sensor is housed within the motor housing.

[0011] The effects of the invention

[0012] According to the present invention, an inverter-integrated motor can be provided that combines improved cooling performance of the current sensor with miniaturization of the overall device. Attached Figure Description

[0013] Figure 1 This is an overall perspective view of an inverter-integrated motor according to one embodiment of the present invention.

[0014] Figure 2 yes Figure 1 The exploded diagram.

[0015] Figure 3 This is a diagram illustrating the internal structure of an existing inverter.

[0016] Figure 4 This is a diagram illustrating the internal structure of the inverter of the present invention.

[0017] Figure 5 yes Figure 1 BB cross-section.

[0018] Figure 6 yes Figure 1 AA cross-section view.

[0019] Figure 7 This is an explanation Figure 6 A diagram showing the connection between the inverter and the motor. Detailed Implementation

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, the embodiments are merely examples for illustrating the present invention, and appropriate omissions and simplifications have been made for clarity. The present invention can be implemented in various other forms. Unless otherwise specified, the constituent elements can be singular or plural. Additionally, for ease of understanding, the positions, sizes, shapes, extents, etc., of the constituent elements shown in the drawings sometimes do not represent actual positions, sizes, shapes, extents, etc. Therefore, the present invention is not limited to the positions, dimensions, shapes, extents, etc., disclosed in the drawings.

[0021] (Composition of an inverter-integrated motor)

[0022] Figure 1 This is an overall perspective view of an inverter-integrated motor according to one embodiment of the present invention. Additionally, the BB wire is broken. Figure 5 The instructions use AA disconnection in Figure 6 Used in the instructions.

[0023] The inverter-integrated motor 100 consists of a motor 1, an inverter 2, and a gearbox 3.

[0024] The inverter-integrated motor 100 has the following structure: the rotating shaft of the motor 1 is mechanically connected to the input shaft of the gearbox 3, the rotational speed of the motor 1 is reduced, and torque is transmitted from the output shaft of the gearbox 3 to the axle of the vehicle. Furthermore, the reduction ratio is determined by the number of teeth of the multiple gears built into the gearbox 3, typically around 8 to 18.

[0025] Figure 2 yes Figure 1 Exploded view of the inverter-integrated motor 100.

[0026] An inlet 6 and an outlet 7 are formed on the surface of the motor housing 8. The inlet 6 and outlet 7 serve as the inlet and outlet for the refrigerant flowing into the interior of the motor housing 8.

[0027] The inverter 2 is secured to the motor 1 by means of the mounting fastener 5 provided on the motor housing 8, which contacts the inverter mounting surface 24 of the motor 1. Similarly, the gearbox 3 is also secured to the motor 1 by means of the mounting fastener 5 provided on the motor housing 8. The heat generated inside the inverter 2 is dissipated to the refrigerant flowing inside the motor 1 through this fastening.

[0028] The motor housing 8 has a current sensor housing 4, which is used to house the current sensor 13 (described later) mounted on the inverter housing 23 when the inverter 2 and the motor 1 are integrated. Details will be described later.

[0029] Figure 3 This is a diagram illustrating the internal structure of the existing inverter 2A.

[0030] Inverter 2A includes: a power module 14 (described later) which houses and integrates power semiconductor switches such as IGBTs or diodes for converting DC power to AC power; a flow path form 12 for cooling the refrigerant flowing through the power module 14; a capacitor 19 for smoothing the DC ripple voltage generated in the DC voltage during power conversion; a current sensor 13A for detecting AC current; an AC bus 15A; a control board; and an EMC filter (unsigned). These components of inverter 2A are integrated within inverter housing 23A to form the main circuit of a three-phase inverter. Furthermore, the flow path form 12 is formed to cover the power module 14.

[0031] Inverter 2A has a three-phase AC bus 15A for electrically connecting capacitor 19 and power module 14 to the aforementioned motor 1. AC bus 15A is output from inverter housing 23A to the outside. Each of the three phase AC bus 15A has a current sensor 13A. In addition to AC bus 15A, a DC connector (unsigned) is also output from inverter housing 23A.

[0032] For vector control, current sensor 13A detects the three-phase AC current values ​​of motor 1 and feeds them back to the motor controller (not shown). Furthermore, since current sensor 13A has a specified heat resistance temperature threshold, a detection error occurs when it operates in a high-temperature environment exceeding this threshold. The specified heat resistance temperature is, for example, 125°C.

[0033] Figure 4 This is a diagram illustrating the internal structure of an inverter 2 according to one embodiment of the present invention.

[0034] The current sensor 13 is formed to surround the AC bus 15 in the circumferential direction, and an insulating resin is disposed between the current sensor 13 and the AC bus 15. Thus, the current sensor 13 becomes a non-contact type current sensor 13 that does not come into contact with the AC bus 15.

[0035] Compared to the conventional inverter 2A, inverter 2 does not extend the AC bus 15 along inverter 2, but rather extends it downwards (inwards in the paper) towards motor 1. Therefore, the volume of inverter housing 23 is smaller than that of conventional inverter housing 23A because the AC bus 15 is not extended.

[0036] Furthermore, the current sensor 13 may not be located on the upper part (front side of the paper) of the flow path forming body 12, but may be located between the inverter 2 and the motor 1, corresponding to the extension direction of the AC bus 15. More specifically, in the inverter housing 23, the current sensor 13 is located on the opposite side of the surface of the flow path forming body 12. Therefore, miniaturization and thinning of the inverter 2 can be achieved.

[0037] Figure 5 yes Figure 1 BB cross-sectional view of inverter-integrated motor 100.

[0038] The electric motor 1 is configured to house a rotor 10 and a stator (stator core) 17 within an electric motor housing 8. The rotor 10 has a rotating shaft 11, which is connected to the input shaft of the gearbox 3 to transmit torque. The rotor 10 rotates inside the stator core 17, supplying power to the electric motor 1 through coils formed around the stator core 17 in the axial direction.

[0039] A coil end 9, which serves as the end of the coil, is formed on the coil formed on the stator core 17. A motor cable 16 for connection to the inverter 2 is output from the coil end 9.

[0040] Within the motor housing 8, a current sensor housing 4 is provided using the space excluding the rotor 10, stator 17, and rotating shaft 11. When the inverter 2 is combined with the motor 1, it is fixed in such a way that the mounting portion of the current sensor 13 fits into the current sensor housing 4 provided on the motor 1. Thus, the current sensor housing 4 houses the current sensor 13 within the motor housing 8 of the motor 1.

[0041] Here, the current sensor 13 needs to be cooled by the flow path forming body 12 of the power module 14, so the position is sandwiched between the coil end 9 disposed in the motor housing 8 and the flow path forming body 12. Thus, at least a portion of the current sensor 13 is housed in the motor housing 8, enabling high-density installation and improving stability.

[0042] The power module 14 and the flow path forming body 12 are positioned relative to the motor rotation shaft 11, with the current sensor 13 sandwiched in between. By doing so, the length of the AC bus 15, which serves as the AC wiring between the motor 1 and the inverter 2, is shortened. This enables the miniaturization and thinning of the inverter-integrated motor 100.

[0043] In summary, the power module 14 is positioned opposite the rotation axis 11 of the motor 1, separated from the stator 17 and the rotor 10. Furthermore, when viewed from the vertical direction of the rotation axis 11, the current sensor 13 is positioned between the flow path forming body 12 and the coil end 9 of the stator 17. Thus, at least a portion of the current sensor 13 is housed within the motor housing 8.

[0044] The flow path of the motor 1 will be described. The refrigerant used by the motor 1 for the overall cooling system flows in from the motor flow path inlet 6, and flows through the flow path forming body 12 and the motor flow path 18, which form a continuous flow path. That is, the refrigerant flowing in the motor flow path 18 also flows in the flow path forming body 12, which is used to cool the power module 14 built into the inverter 2, and the motor 1 and inverter 2 share the same refrigerant. The refrigerant flowing in the flow path forming body 12 and the motor flow path 18 is discharged from the motor flow path outlet 7 to the outside of the inverter-integrated motor 100. This refrigerant flow structure enables cooling of both the motor 1 and the inverter 2.

[0045] By cooling the flow path forming body 12 of the cooling power module 14, the current sensor 13 and the air layer in its surrounding space can be cooled, thereby cooling the current sensor 13. Therefore, even if the environment inside the motor housing 8 is a high temperature environment above the heat resistance temperature of the current sensor 13, the current sensor 13 is cooled by the refrigerant flowing in the motor flow path 18, and the temperature of the current sensor 13 can be maintained at a temperature lower than the specified allowable heat resistance temperature. As a result, the detection error of the current sensor 13 can be reduced and the reliability can be improved. In addition, the temperature of the refrigerant is, for example, below 70°C.

[0046] Furthermore, through the above configuration, the capacitor 19 disposed in the inverter 2 not only receives cooling from the flow path forming body 12, but is also indirectly cooled from the motor housing 8 via the inverter frame 23, thereby improving cooling performance. As a result, the inverter-integrated motor 100 can operate with high precision and high reliability.

[0047] Therefore, the inverter 2 does not need to extend the inverter housing 23 to accommodate the current sensor 13 and the AC bus 15. Furthermore, since the inner wall of the current sensor housing 4 is close to the flow path forming body 12 of the inverter 2 or the motor flow path 18, the current sensor housing 4 is a structure capable of thermal movement relative to the surrounding inner wall. Therefore, not only can the inverter 2 be miniaturized, but the inverter-integrated motor 100 with improved cooling performance can also be achieved.

[0048] Figure 6 yes Figure 1 AA cross-sectional view of inverter-integrated motor 100.

[0049] The AC bus 15 passes through a central portion to form a perforated current sensor 13, with the perforated portion separated by insulating resin. Thus, the current sensor 13 becomes a non-contact sensor. Furthermore, when the inverter 2 and motor 1 are integrated, and the current sensor 13 is housed in the current sensor housing 4, the AC bus 15 is connected to the motor cable 16 of the motor 1. Therefore, the current sensor housing 4 improves the positioning accuracy of the current sensor 13 and the AC bus 15.

[0050] At this time, the flow path of the motor flow path 18 and the flow path forming body 12 are also connected, and as described above, the refrigerant flowing inside each flow path is shared. As a result, the thermal resistance between the current sensor 13 and the flow path forming body 12 can be reduced.

[0051] This configuration significantly shortens the wiring length connecting the inverter 2's AC bus 15 and motor cable 16, and also reduces the size of the inverter 2. Furthermore, the current sensor 13 is cooled not only by the surface of the flow path forming body 12 but also by the motor flow path 18, ensuring high-precision and high-reliability operation even inside the high-temperature environment of the motor housing 8, thus guaranteeing sensing accuracy and reliability.

[0052] Figure 7 This is an explanation Figure 4 A diagram of the connection between inverter 2 and motor 1.

[0053] The three-phase current portion of the current sensor 13 corresponding to the AC bus 15 is mounted on the current sensor mounting portion 20, and at least a portion of the current sensor 13 is in contact with and fixed to the current sensor cooling surface 21. Thus, the current sensor 13 is cooled by the flow path forming body 12, and its temperature is maintained below a specified allowable temperature.

[0054] A current sensor mounting section 20 is provided on the surface of the inverter housing 23 opposite to the flow path forming body 12, and a current sensor 13 is mounted thereon. In addition, to improve the stability of the current sensor, a cover 22 is used to seal the current sensor mounting section 20.

[0055] The AC bus 15, which is connected to the power module, passes through the cover 22 and is connected to the motor. Furthermore, as described above, when the inverter 2 and the motor 1 are integrated, the current sensor mounting portion 20 engages with the housing portion 4 formed on the motor housing 8 for housing the current sensor 13.

[0056] This configuration provides thermal protection for the current sensor 13, shielding it from the high-temperature environment inside the motor 1 and the oil in the gears inside the gearbox 3. Alternatively, the current sensor 13 can be a coreless sensor. In this case, a cooling IC and a shielding structure are required. This coreless sensor is also essentially a non-contact sensor, configured in conjunction with the AC bus 15 of the inverter 2.

[0057] According to the first embodiment of the present invention described above, the following effects are achieved.

[0058] (1) The inverter-integrated motor 100 includes: a power module 14 that converts direct current into alternating current; a flow path forming body 12 formed such that refrigerant flows through and covers the power module 14; an inverter 2 that internally houses the power module 14 and the flow path forming body 12; a current sensor 13 that detects alternating current; and a motor 1 consisting of a motor housing 8 housing a stator 17 and a rotor 10. The power module 14 is positioned opposite the rotation axis 11 of the motor 1, separated by the stator 17 and rotor 10. When viewed perpendicularly to the rotation axis 11, the current sensor 13 is positioned between the flow path forming body 12 and the coil ends 9 of the stator 17, and at least a portion of the current sensor 13 is housed within the motor housing 8. This provides an inverter-integrated motor 100 that balances the cooling performance of the inverter 2 with miniaturization.

[0059] (2) The current sensor 13 of the inverter-integrated motor 100 is located in the frame 23 of the inverter 2 and is disposed on the opposite side of the mounting surface of the flow path forming body 12. This enables the inverter 2 to be miniaturized.

[0060] (3) The current sensor 13 of the inverter-integrated motor 100 is mounted on the mounting part 20, which is formed in the frame 23 of the inverter 2 for mounting the current sensor 13. When the inverter 2 and the motor 1 are integrated, the mounting part 20 fits into the housing part 4 formed in the motor housing 8 for housing the current sensor. Therefore, while improving the fixation of the current sensor 13, it also helps to miniaturize the inverter-integrated motor 100.

[0061] (4) The mounting part 20 of the inverter-integrated motor 100 is sealed by the cover 22, and the AC bus 15 connected to the power module 14 passes through the cover 22 and is connected to the motor 1. This improves the stability of the current sensor 13.

[0062] (5) The current sensor 13 of the inverter-integrated motor 100 is not in contact with the AC bus 15. In this way, while adopting a non-contact type, the space required to install the current sensor 13 can be reduced.

[0063] (6) The current sensor 13 of the inverter-integrated motor 100 is a coreless current sensor. In this way, the same effect can be obtained even if other types of current sensors are used.

[0064] Furthermore, the above description is merely an example, and in interpreting the invention, there are no limitations or constraints on the correspondence between the described matters of the above embodiments and the described matters of the claims. Additionally, deletions, substitutions, and additions of other components can be made without departing from the technical concept of the invention, and such methods are also included within the scope of this invention.

[0065] Explanation of symbols

[0066] 100…Inverter integrated motor, 1…Motor, 2…Inverter, 3…Gearbox, 4…Current sensor housing, 5…Fixing part, 6…Motor flow path inlet, 7…Motor flow path outlet, 8…Motor housing, 9…Coil end, 10…Rotor, 11…Rotating shaft, 12…Flow path forming body, 13, 13A…Current sensor, 14…Power module, 15, 15A…AC bus, 16…Motor cable, 17…Stator (stator core), 18…Motor flow path, 19…Capacitor, 20…Current sensor mounting part, 21…Current sensor cooling surface, 22…Current sensor housing cover, 23, 23A…Inverter frame, 24…Inverter mounting surface.

Claims

1. An inverter-integrated motor, characterized in that, have: A power module that converts direct current into alternating current; A flow path forming body is formed such that a refrigerant flows through the power module and covers the power module; An inverter, which internally houses the power module and the flow path forming body; A current sensor that detects the alternating current; An electric motor, which has a stator and a rotor; and The motor housing houses the stator and the rotor. The power module is positioned opposite the rotation axis of the motor, separated from the stator and the rotor. When viewed from the vertical direction of the rotation axis, the current sensor is disposed between the flow path forming body and the coil end of the stator, and at least a portion of the current sensor is housed within the motor housing.

2. The inverter-integrated motor according to claim 1, characterized in that, In the inverter housing, the current sensor is disposed on the opposite side of the mounting surface of the flow path forming body.

3. The inverter-integrated motor according to claim 2, characterized in that, The current sensor is mounted on the mounting portion formed in the frame of the inverter. When the inverter and the motor are integrated, the mounting portion is fitted into a housing portion formed in the motor housing for housing the current sensor.

4. The inverter-integrated motor according to claim 3, characterized in that, The mounting section is sealed by the cover. An AC busbar connected to the power module passes through the cover and is connected to the motor.

5. The inverter-integrated motor according to claim 4, characterized in that, The current sensor is not in contact with the AC bus.

6. The inverter-integrated motor according to claim 5, characterized in that, The current sensor is a coreless current sensor.

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