stator of an electric motor

Abstract

In a stator of an electric motor according to the present application, a temperature sensor mounted to an electrically conductive member is covered with resin, and the amount of resin used can be reduced to inhibit the increase in size. Since the temperature sensor (38) for detecting the temperature of the electric motor (MG) is inserted into the circular hole (46) formed in the neutral bus bar (36), the thickness (L1) of the portion covered with the resin portion (40) can be reduced by an amount corresponding to the amount by which the temperature sensor (38) is inserted into the circular hole (46). As a result, the amount of resin used is reduced, and the increase in size of the device can be inhibited.

Description

Technical Field

[0001] This invention relates to the mounting structure of a temperature sensor installed on the stator of an electric motor. Background Technology

[0002] Patent Document 1 describes a mounting structure for a temperature sensor installed on the stator of an electric motor. Specifically, Patent Document 1 describes a structure in which a temperature sensor is mounted on a conductive member connected to a stator coil mounted on the stator core. Furthermore, Patent Document 1 describes a structure in which the front ends of the stator coils protruding from the stator core towards the rotation axis are welded together, and the front ends of each coil are covered with resin to ensure good insulation of these welded portions. Moreover, Patent Document 1 describes that, to prevent the element portion of the temperature sensor from contacting refrigerant such as cooling oil, which could cause the sensor reading to be lower than the actual coil temperature, the temperature sensor and the front ends of the stator coils are covered together with resin.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-114877 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in the temperature sensor mounting structure described in Patent Document 1, the thickness of the mounting portion of the temperature sensor increases because the conductive member is bent and the temperature sensor is mounted between the conductive members. As a result, there is a problem of increased resin usage covering the temperature sensor and conductive member, leading to a larger overall size.

[0008] The present invention was made against the background described above, and its object is to provide a structure in the stator of an electric motor having a structure in which a temperature sensor mounted on a conductive member is covered with resin, thereby reducing the amount of resin used and suppressing the increase in size.

[0009] Technical solutions for solving the problem

[0010] The subject of the first invention is (a) a stator of an electric motor, comprising: a cylindrical stator core arranged about a rotation axis; a plurality of coils inserted into a slot through which the stator core passes in the direction of the rotation axis; a conductive member electrically connected to the coils; a temperature sensor mounted on the conductive member; and a resin portion covering at least a portion of the conductive member and the temperature sensor, wherein the stator of the electric motor is characterized in that, (b) a hole extending along the rotation axis of the stator core is formed in the conductive member, and at least a portion of the temperature sensor is inserted into the hole.

[0011] The essence of the second invention is that, in the first invention, the temperature sensor has a base and a protrusion protruding from the base, the protrusion being inserted into the hole.

[0012] The essence of the third invention is that, in the first or second invention, the temperature sensor is inserted into the hole in an interference fit state.

[0013] The main point of the fourth invention is that, in any one of the first to third inventions, the conductive member is a neutral line busbar.

[0014] Invention Effects

[0015] According to the first invention, the temperature sensor is inserted into a hole formed in the conductive member, thus reducing the thickness of the portion covered by the resin by an amount corresponding to the amount of temperature sensor inserted into the hole. As a result, the amount of resin used is reduced, and the size of the device can be kept smaller.

[0016] According to the second invention, since the protrusion protruding from the base of the temperature sensor is inserted into the hole, the length of the portion of the temperature sensor inserted into the hole can always be kept constant.

[0017] According to the third invention, since the temperature sensor is inserted into the hole with an interference fit, it prevents the temperature sensor from falling out of the hole after it is assembled into the neutral busbar. Furthermore, since the temperature sensor and the neutral busbar are in close contact, the temperature tracking performance of the temperature sensor is improved.

[0018] According to the fourth invention, since the conductive component is a neutral busbar, the temperature sensor improves the accuracy of temperature detection of the motor by detecting the temperature of the neutral busbar, which is constantly subjected to current during operation. Attached Figure Description

[0019] Figure 1 This is a diagram showing an electric motor mounted on a vehicle as an embodiment of the present invention, viewed along the axis of rotation.

[0020] Figure 2 It is Figure 1 The simplified AA section view.

[0021] Figure 3 Is Figure 2 The sectional view after cutting at the cutting line BB.

[0022] Figure 4 This diagram shows the state of the manufacturing transition when the resin part covers the welded part, the neutral busbar, and the temperature sensor.

[0023] Figure 5 This is a diagram showing the dimensional relationship between the temperature sensor and the neutral busbar before assembly.

[0024] Figure 6 This is a diagram illustrating the construction of a neutral busbar and a temperature sensor mounted on the neutral busbar, corresponding to other embodiments of the present invention. Detailed Implementation

[0025] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Furthermore, in the following embodiments, the drawings have been appropriately simplified or modified, and the dimensions and shapes of the parts may not be accurately depicted.

[0026]

Example 1

[0027] Figure 1 This is a view of the electric motor MG mounted on a vehicle, incorporating the present invention, viewed along the rotation axis CL. The electric motor MG is housed within a housing 12, which is a non-rotating component. The electric motor MG is arranged centered on the rotation axis CL. The electric motor MG is configured to include: a rotor 14, configured to rotate about the rotation axis CL; and a stator 16, disposed on the outer periphery of the rotor 14.

[0028] The rotor 14 is cylindrical and is rotatably supported by the housing 12 via bearings (not shown) located at both ends along the rotation axis CL. The stator 16 is cylindrical and is fastened to the housing 12 by bolts (not shown). Therefore, the stator 16 is fixed to the housing 12 in a non-rotatable manner. A predetermined gap is formed radially between the rotor 14 and the stator 16.

[0029] The rotor 14 houses a plurality of magnets 14a. The stator 16 includes a cylindrical stator core 18 arranged about the rotation axis CL, and a plurality of stator coils 20 extending through the stator core 18 along the rotation axis CL. The stator coils 20 are formed of rectangular cross-section wires (not shown) with an insulating film, and one side has a dimension approximately the same as the dimension of the gap in the slot 22 described later. Furthermore, the stator coils 20 correspond to the coils of the present invention.

[0030] The stator core 18 is formed into a cylindrical shape by stacking multiple electromagnet steel plates. Multiple slots 22 are formed in a radial pattern when viewed along the rotation axis CL. Each slot 22 is a cut extending radially outward from the inner circumferential surface of the stator core 18. The multiple slots 22 are arranged at equal angular intervals in the circumferential direction of the stator core 18. Furthermore, the slots 22 penetrate the stator core 18 in the direction of the rotation axis CL.

[0031] Multiple stator coils 20 are inserted into each slot 22. When viewed along the rotation axis CL, multiple stator coils 20 are arranged radially in each slot 22. The stator coils 20 are U-shaped, with a pair of front ends of each stator coil 20 inserted into the slot 22 from one side to the other along the rotation axis CL of the stator core 18. Therefore, each end of the stator coil 20 protrudes from one end along the rotation axis CL of the stator core 18 toward the rotation axis CL. By binding the portion of the stator coil 20 that protrudes from the stator core 18 toward the rotation axis CL, a coil end 24, indicated by a single-dot dash, is formed. At the end of the stator coil 20 forming the coil end 24 along the rotation axis CL, a welded portion 26 is formed by welding the front ends of the individual stator coils 20 together (see reference). Figure 2 ).

[0032] When mounted in a vehicle, a cooling pipe 28 is arranged above the coil end 24 in the vertical direction, along the rotation axis CL. Cooling oil cooled by the oil cooler 30 is drawn into the cooling pipe 28 by a mechanical oil pump 32.

[0033] Figure 1 The arrows indicate the flow of cooling oil. Multiple oil drain holes 34 are formed in the cooling pipe 28, from which cooling oil is discharged. The cooling oil discharged from the oil drain holes 34 sprays towards the coil end 24. The cooling oil adhering to the coil end 24 moves downwards along the coil end 24 as indicated by the arrows, thus cooling the coil end 24. Furthermore, the cooling oil reaching below the coil end 24 moves to the lower part of the housing 12, is cooled by the oil cooler 30, and is then supplied back to the cooling pipe 28 via the mechanical oil pump 32. In this way, the cooling oil circulates within the housing 12 while cooling the coil end 24.

[0034] Figure 2 It is Figure 1 A simplified diagram of the AA sectional view. Figure 2 In this context, the vertical direction of the paper corresponds to the direction of the rotation axis CL, and the horizontal direction of the paper corresponds to the radial direction centered on the rotation axis CL. For example... Figure 2As shown, a coil end 24 is formed by multiple stator coils 20 protruding from their ends in the direction of the rotation axis CL of the stator core 18. Furthermore, at the front end of the coil end 24, a welded portion 26 is formed by welding the front ends of individual stator coils 20 together. The coil end 24 and the welded portion 26 are formed in a ring shape with the rotation axis CL as the center.

[0035] A neutral busbar 36 is electrically connected to the stator coil 20. The neutral busbar 36 connects the ends of the U-phase, V-phase, and W-phase coils constituting the stator coil 20, forming a Y-connected neutral point. Furthermore, a temperature sensor 38 for detecting the motor temperature of the electric motor MG is installed in the neutral busbar 36. Since current flows continuously through the neutral busbar 36 during vehicle operation (including when the vehicle is stopped), the accuracy of motor temperature detection by the temperature sensor 38 is improved by installing it in the neutral busbar 36. Additionally, the temperature sensor 38 is installed in the space formed between the neutral busbar 36 and the stator core 18, thus preventing an increase in the size of the electric motor MG due to the installation of the temperature sensor 38. Furthermore, the neutral busbar 36 corresponds to the conductive component of this invention.

[0036] Furthermore, to ensure the insulation of the welded portion 26 formed by welding the front ends of the stator coils 20 together, the welded portion 26 is covered by a resin portion 40 made of resin. Moreover, to prevent the thermistor element portion 48 (see reference) of the temperature sensor 38 mounted on the neutral busbar 36 from being damaged, the resin portion 26 is also covered. Figure 3 The near-side contact with cooling oil reduces the temperature detection accuracy of the temperature sensor 38, and a portion of the neutral busbar 36 and the temperature sensor 38 are also covered by the resin part 40. Therefore, the resin part 40 integrally covers the welded part 26, the neutral busbar 36, and a portion of the temperature sensor 38.

[0037] As described above, by covering a portion of the temperature sensor 38 with the resin portion 40, the decrease in the sensor measurement value of the temperature sensor 38 due to cooling oil is suppressed. However, the thickness of the resin portion 40 in the rotation axis CL direction (in...) Figure 2 The thickness (equivalent to thickness L1) is increased by an amount corresponding to the amount of resin covering the temperature sensor 38. As a result, the amount of resin used increases. Furthermore, when the length of the rotation axis CL direction of the motor MG is limited due to constraints such as those related to the mounting of the motor MG, the length of the coil end 24 in the rotation axis CL direction that can be cooled by cooling oil (in...) Figure 2The length L2 (equivalent to the thickness of the resin portion 40) is relatively shorter. As a result, the surface area of ​​the coil end 24 that can contact the cooling oil is reduced, and the cooling effect of the cooling oil on the stator coil 20 is reduced. Relatedly, there is also a possibility that the output torque of the motor MG may be limited due to the temperature constraint of the stator coil 20.

[0038] To avoid the above problems, at least a portion of the temperature sensor 38 is inserted into a circular hole 46 formed in the neutral busbar 36. Figure 3 Is Figure 2 A sectional view after cutting at the section line BB. Figure 3 In the diagram, the vertical direction on the paper corresponds to the rotation axis CL. Additionally, in... Figure 3 In the image, a CC cross-sectional view of the temperature sensor 38 is shown at the top of the paper. Figure 3 In this text, the resin portion 40 is omitted. Additionally, the circular hole 46 corresponds to the hole in this invention.

[0039] The temperature sensor 38 includes a thermistor element 48 and a sensor housing 50 that protects the thermistor element 48. The thermistor element 48 is housed within the sensor housing 50, which is made of resin. Additionally, two leads 52a and 52b are connected to the thermistor element 48.

[0040] The sensor housing 50 is formed in a convex shape (stepped shape) having a plate-shaped base 54 and a cylindrical protrusion 56. The plate-shaped base 54 has a predetermined thickness, and the cylindrical protrusion 56 is thicker than the neutral busbar 36 and protrudes vertically from the base 54. The neutral busbar 36 has a predetermined thickness in the direction of the rotation axis CL. A circular hole 46 extending along the thickness direction, i.e., the direction of the rotation axis CL, is formed in the neutral busbar 36.

[0041] The protrusion 56 of the temperature sensor 38 is inserted into the circular hole 46, which has a circular cross-section, formed in the neutral busbar 36. The temperature sensor 38 is inserted to the position where the base 54 of the sensor housing 50 abuts against the neutral busbar 36.

[0042] Therefore, as Figure 2As shown, the thickness L1 of the resin portion 40 can be reduced by the amount of dimension L3 into which the temperature sensor 38 is inserted into the circular hole 46. As a result, the amount of resin used to form the resin portion 40 can be reduced. Furthermore, even when the size of the portion protruding from the stator core 18 of the motor MG in the direction of the rotation axis CL is limited due to mounting issues, the thickness L1 of the resin portion 40 can be reduced, thus allowing the length L2 of the coil end 24, which can be cooled by cooling oil, in the direction of the rotation axis CL to be relatively longer relative to the thickness L1. As a result, the surface area of ​​the coil end 24 that can contact the cooling oil increases, thereby improving the cooling performance of the cooling oil on the motor MG. Relatedly, the output limitation caused by the heat of the motor MG is alleviated, and the motor MG can be miniaturized.

[0043] Figure 4 The diagram shows the state during the manufacturing transition when the weldment 26, neutral busbar 36, and temperature sensor 38 are covered with resin section 40. Figure 4 In the middle, the area below the paper corresponds to the vertical bottom during manufacturing. When molding the resin section 40, the weld section 26 is pre-formed, and with the temperature sensor 38 mounted on the neutral busbar 36, the weld section 26, the neutral busbar 36, and the temperature sensor 38 are immersed in liquid resin filled in the mold 42. When the liquid resin cures in this state, the resin section 40, formed by covering the weld section 26, the neutral busbar 36, and the temperature sensor 38 with resin, is molded.

[0044] Figure 5 This diagram shows the dimensional relationship between the temperature sensor 38 and the neutral busbar 36 before assembly. Before the temperature sensor 38 is inserted into the circular hole 46 of the neutral busbar 36, the outer diameter d1 of the cylindrical protrusion 56 is slightly larger than the inner diameter d2 of the circular hole 46. Therefore, during the assembly transition period, the temperature sensor 38 is pressed into the circular hole 46. Subsequently, after the temperature sensor 38 is inserted into the circular hole 46, it is fixed to the neutral busbar 36 in an interference fit state. Furthermore, the dimensional difference between the outer diameter d1 of the protrusion 56 and the inner diameter d2 of the circular hole 46 is set to the degree of interference fit between the protrusion 56 and the circular hole 46 after assembly.

[0045] Therefore, when the temperature sensors 38 are mounted on the neutral busbar 36 and immersed in liquid resin, the temperature sensors 38 are fixed to the circular hole 46 of the neutral busbar 36 with an interference fit. This prevents the temperature sensors 38 from shifting out of the circular hole 46 during the manufacturing transition, thus improving manufacturability. Furthermore, since the resin near the thermistor element portion 48 is in close contact with the neutral busbar 36, air or resin ingress between the temperature sensor 38 and the neutral busbar 36 is suppressed, thereby reducing the thermal resistance caused by air or other contaminants between the temperature sensor 38 and the neutral busbar 36. As a result, the temperature tracking performance of the temperature sensor 38 is improved.

[0046] As described above, according to this embodiment, since the temperature sensor 38 is inserted into the circular hole 46 formed in the neutral busbar 36, the thickness L1 of the portion covered by the resin portion 40 can be reduced by an amount corresponding to the amount by which the temperature sensor 38 is inserted into the circular hole 46. As a result, the amount of resin used is reduced, and the situation of increasing the size of the device can be suppressed.

[0047] Furthermore, according to this embodiment, since the protrusion 56 protruding from the base 54 of the temperature sensor 38 is inserted into the circular hole 46, the length of the portion of the temperature sensor 38 inserted into the circular hole 46 can always be kept constant. Additionally, since the temperature sensor 38 is inserted into the circular hole 46 in an interference fit state, it prevents the temperature sensor 38 from falling out of the circular hole 46 after it is assembled to the neutral busbar 36. Furthermore, since the temperature sensor 38 and the neutral busbar 36 are in close contact, the temperature tracking performance of the temperature sensor 38 can be improved. Moreover, by mounting the temperature sensor 38 on the neutral busbar 36, which is constantly supplied with current during operation, the temperature detection accuracy of the temperature sensor 38 for the electric motor MG is improved.

[0048] Other embodiments of the present invention will now be described. Furthermore, in the following description, parts common to the embodiments described above will be labeled with the same reference numerals, and their descriptions will be omitted.

[0049]

Example 2

[0050] Figure 6 This diagram illustrates the configuration of the neutral busbar 80 and the temperature sensor 82 mounted on the neutral busbar 80, corresponding to other embodiments of the present invention. Furthermore, descriptions of configurations other than the neutral busbar 80 and the temperature sensor 82 are omitted as they are the same as in the above embodiments. The neutral busbar 80 corresponds to the conductive member of the present invention.

[0051] like Figure 6As shown, a square hole 84 for inserting a temperature sensor 82 is formed in the neutral busbar 80. The cross-section of the square hole 84 is square. Furthermore, the square hole 84 corresponds to the hole of the present invention.

[0052] The temperature sensor 82 includes a thermistor element portion 48 and a resin sensor housing 86 for protecting the thermistor element portion 48. The sensor housing 86 is formed with a flat base 88 and a protrusion 90 that is thicker than the neutral busbar 80 and protrudes vertically from the base 88, forming a convex shape (stepped shape). As shown in the DD cross-sectional view above the paper, the protrusion 90 is formed into a quadrilateral (square) shape. Therefore, the protrusion 90 of the temperature sensor 82 can be inserted into the square hole 84 of the neutral busbar 80. In the assembled state, the protrusion 90 passes through the square hole 84 of the neutral busbar 80. Thus, the shape of the hole (square hole 84) of the neutral busbar 80 into which the temperature sensor 82 is inserted is formed into a quadrilateral shape, and the shape of the protrusion (protrusion 90) of the temperature sensor 82 is formed into a quadrilateral corresponding to the shape of the square hole 84. Even when formed as described above, by inserting the protrusion 90 of the temperature sensor 82 into the square hole 84 of the neutral busbar 80, the thickness L1 of the resin portion (refer to) can be reduced. Figure 2 The amount of thinning corresponds to the amount by which the protrusion 90 is inserted into the square hole 84. As a result, the amount of resin used can be reduced, and the cooling performance of the cooling oil on the motor MG is improved because the surface area of ​​the coil end 24 that can contact the cooling oil is increased.

[0053] Furthermore, before the temperature sensor 82 is assembled into the neutral busbar 80, the dimension s1 of one side of the convex portion 90, which is shaped as a quadrangular prism, is slightly larger than the dimension s2 of one side of the square hole 84. Therefore, during the assembly transition period of the temperature sensor 82, the temperature sensor 82 is pressed into the square hole 84. Consequently, when the temperature sensor 82 is inserted into the square hole 84, the temperature sensor 82 is fixed to the neutral busbar 80 in an interference fit. As a result, it prevents the temperature sensor 82 from deviating from the square hole 84 during the manufacturing transition period, or improves the temperature tracking performance of the temperature sensor 82 because the temperature sensor 82 is in close contact with the neutral busbar 80. As described above, according to this embodiment, the same effects as in the previous embodiment can also be obtained.

[0054] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is also applicable to other methods.

[0055] For example, in the above embodiment, the circular hole 46 formed in the neutral busbar 36 is formed as a perfect circle, but it can also be formed as an ellipse. Correspondingly, the shape of the protrusion 56 of the temperature sensor 38 can also be formed as an ellipse. Similarly, the square hole 84 formed in the neutral busbar 80 is formed as a square, but it can also be formed as a rectangle. Correspondingly, the shape of the protrusion 90 of the temperature sensor 82 can also be formed as a rectangle. Moreover, the shape of the hole formed in the neutral busbar is not limited to circular and quadrilateral shapes; for example, it can be appropriately changed to a triangle or trapezoid. Similarly, the shape of the protrusion of the temperature sensor can also be appropriately changed according to the shape of the hole.

[0056] Furthermore, in the above embodiments, the circular hole 46 formed in the neutral busbar 36 and the square hole 84 formed in the neutral busbar 80 are both through holes that penetrate the neutral busbars 36 and 80 in the thickness direction. However, the holes formed in the neutral busbars are not necessarily limited to through holes. For example, they can also be cuts or holes with a specified depth.

[0057] Furthermore, in the above embodiments, the circular hole 46 formed in the neutral busbar 36 and the square hole 84 formed in the neutral busbar 80 are both formed inside the neutral busbars 36 and 80. However, a cut can also be formed at the edge of the neutral busbar, and a temperature sensor can be inserted into the cut. That is, the cut is formed at the edge of the neutral busbar and functions as a hole for embedding the temperature sensor.

[0058] Furthermore, in the above embodiments, the sensor housings 50 and 86 of the temperature sensors 38 and 82 are respectively formed into stepped shapes consisting of bases 54 and 88 and protrusions 56 and 90. However, the present invention is not necessarily limited to stepped shapes; shapes without steps are also possible. Accordingly, the entire temperature sensor can be inserted into the hole formed in the neutral busbar. That is, it is sufficient that at least a portion of the temperature sensor is inserted into the hole formed in the neutral busbar.

[0059] Furthermore, the above method is merely one implementation method, and the present invention can be implemented in various ways with modifications and improvements based on the knowledge of those skilled in the art.

[0060] Label Explanation

[0061] 16: Stator

[0062] 18: Stator core

[0063] 20: Stator coil (coil)

[0064] 22: Slot

[0065] 26: Welding section

[0066] 36, 80: Neutral busbar (conductive component)

[0067] 38, 82: Temperature sensors

[0068] 40: Resin section

[0069] 46: Round hole (hole)

[0070] 54, 88: Base

[0071] 56, 90: convex part

[0072] 84: Square hole (hole)

[0073] MG: Electric motor

[0074] CL: Axis of rotation

Claims

1. A stator (16) for an electric motor (MG), comprising: a cylindrical stator core (18) arranged about a rotation axis (CL); a plurality of coils (20) inserted into a slot (22) through which the stator core (18) passes in the direction of the rotation axis (CL), the front ends of the coils (20) being welded together to form a welded portion (26); conductive members (36, 80) electrically connected to the coils (20); temperature sensors (38, 82) mounted on the conductive members (36, 80); and a resin portion (40) integrally covering at least a portion of each of the welded portion (26), the conductive members (36, 80), and the temperature sensors (38, 82), characterized in that... Holes (46, 84) extending along the rotation axis (CL) of the stator core (18) are formed in the conductive members (36, 80), and at least a portion of the temperature sensors (38, 82) is inserted into the holes (46, 84). The temperature sensor (38, 82) has a plate-shaped base (54, 88) and a cylindrical protrusion (56, 90) protruding vertically from the base (54, 88), the protrusion (56, 90) being thicker than the conductive member (36, 80) and inserted into the hole (46, 84). The temperature sensors (38, 82) are inserted into the holes (46, 84) with an interference fit. The base (54, 88) of the temperature sensor (38, 82) abuts against the conductive member (36, 80), and the temperature sensor (38, 82) is inserted into the position where the base (54, 88) abuts against the conductive member (36, 80).

2. The stator (16) of the electric motor (MG) according to claim 1, characterized in that, The conductive components (36, 80) are neutral line busbars (36, 80).

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