electric motor

Abstract

The present invention provides an electric motor that ensures electrical conductivity between the conductor and the terminal, and prevents the conductor from breaking and falling off the terminal, especially when aluminum wire is used as the conductor. [Solution] An electric motor according to one embodiment of the present invention comprises a stator core having a plurality of teeth, a coil wound around the teeth, and a terminal to which a conductor extending from the coil is connected, wherein the conductor is an aluminum wire whose conductor portion is made of aluminum or an aluminum alloy, and the terminal has a clamping portion for clamping the conductor, the clamping portion has a first clamping region and a second clamping region, the amount of crushing of the conductor portion of the conductor in the first clamping region and the amount of crushing of the conductor portion of the conductor in the second clamping region are different from each other, and the first clamping region and the second clamping region are arranged side by side in the direction in which the conductor extends in the portion clamped by the clamping portion.

Description

Technical Field

[0001] The present invention relates to an electric motor in which an aluminum wire is used for a conducting wire.

Background Art

[0002] Conventionally, the end of a conducting wire that continuously extends from a coil of a stator of a rotating electrical machine such as an electric motor or a generator is connected to a terminal. As the conducting wire, it is common to use a copper wire containing copper or a copper alloy, or an aluminum wire containing aluminum or an aluminum alloy. As a terminal used for connecting the conducting wire of the rotating electrical machine, there is known one having a hooked portion formed by folding back a part of the terminal into a hooked shape. For example, in Patent Document 1, with the end of a conducting wire (aluminum wire) extending from a coil sandwiched inside the hooked portion of the terminal, the end of the conducting wire and the hooked portion of the terminal are fixed to each other by thermal caulking.

[0003] Generally, a conducting wire has a conductor portion formed of a conductor and an insulating coating portion covering the conductor portion. In thermal caulking, resistance welding and caulking are performed simultaneously or continuously. In resistance welding, by energizing an electrode while sandwiching the hooked portion of the terminal together with the conducting wire with the electrode for resistance welding, the coating portion of the conducting wire is melted to expose the conductor portion, and at the same time, the hooked portion of the terminal and the conductor portion of the conducting wire, which are both made of metal, are heated to become easily deformable (soft). In caulking, the conductor portion of the conducting wire and the hooked portion of the terminal, which have become easily deformable by resistance welding, are joined by caulking (solid-phase bonding) to electrically conduct them.

[0004] By the way, copper or brass is used as the main material for the terminal having a hooked portion. On the other hand, aluminum, which is the main raw material of the aluminum wire, has properties of having a lower tensile strength (being easily broken) and a lower elastic modulus than copper, which is the main raw material of the copper wire. Also, in terms of thermal properties, aluminum and aluminum alloys have properties of having a larger linear expansion coefficient and a lower melting point compared to copper and brass.

[0005] When copper wire is used as the conductor, its tensile strength, elastic modulus, and coefficient of linear expansion are equivalent to those of terminals, which are also primarily made of copper. Therefore, both the copper wire and the terminals expand and contract similarly during the heat crimping process, resulting in stable conductivity even after settling.

[0006] However, when using aluminum wire as the conductor, the coefficient of thermal expansion of aluminum or aluminum alloy, which is the material of the conductor part of the aluminum wire, is larger than that of copper or brass, which are the main materials of the terminals. Therefore, even if the aluminum wire and the terminal are in contact with each other immediately after resistance welding, as time passes and the terminal cools, the amount of shrinkage of the aluminum wire will be greater than the amount of shrinkage of the terminal. This can cause a gap to form between the aluminum wire and the terminal due to the difference in the degree of shrinkage (difference in shrinkage amount), resulting in insufficient contact between them, and potentially leading to unstable electrical conductivity between the conductor part of the aluminum wire and the terminal.

[0007] On the other hand, in order to ensure electrical conductivity between the terminal and the conductor, one method is to increase the amount of deformation (compression) of the conductor when it is crimped by the terminal. For example, Patent Document 2 employs a method in which alternating protrusions are provided on the clamping part of the terminal, so that the protrusions bite into the conductor and increase the contact area between them. However, with this method, if the amount of deformation (compression) of the conductor becomes too large as a result of increasing the height of the protrusions, there is a risk that the conductor may break and fall off the terminal.

[0008] To simultaneously solve the problems of unstable conductivity and wire breakage, Patent Document 3 discloses a method for defining the range of compression at a terminal (amount of deformation of the conductor) by causing the clamping parts to collide with each other midway through the compression of the conductor when it is clamped (so that the conductor does not compress any further as it hits a bent part or protrusion). However, in Patent Document 3, since the entire direction in which the conductor clamped by the terminal extends is compressed to a constant amount relative to the radial direction of the conductor, there is a risk that variations (individual differences) may occur in the amount of compression of the conductor clamped by the terminal depending on the positional relationship between the bent part (or protrusion) and the conductor. For example, a conductor clamped near the bottom of a U-shaped clamping part tends to be compressed less, while a conductor clamped near the upper end of a U-shaped clamping part tends to be compressed more. As a result, there is a risk that some wires may break and detach from the terminal due to excessive compression of the area between the terminals, or that some wires may have insufficient conductivity due to insufficient compression of the area between the terminals. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2015-053853 [Patent Document 2] Japanese Patent Publication No. 2013-027079 [Patent Document 3] Japanese Patent Publication No. 2013-207867 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] In view of the above circumstances, the object of the present invention is to provide an electric motor that can stably ensure electrical conductivity between the conductor and the terminal when aluminum wire is used as the conductor, and that can prevent the conductor from breaking and falling off the terminal. [Means for solving the problem]

[0011] An electric motor according to one embodiment of the present invention comprises a stator core having a plurality of teeth, coils wound around the teeth, and terminals to which conductors extending from the coils are connected, The aforementioned conductor is an aluminum wire whose conductor portion is made of aluminum or an aluminum alloy. The terminal is equipped with a clamping portion for clamping the conductor, The clamping portion has a first clamping region and a second clamping region, wherein the amount of crushing of the conductor portion of the wire in the first clamping region and the amount of crushing of the conductor portion of the wire in the second clamping region are different from each other. The first clamping region and the second clamping region are arranged side by side in the direction in which the conductor extends within the portion clamped by the clamping portion.

[0012] As a result, the above-mentioned electric motor can have two separate clamping regions at the terminal: one that significantly compresses the conductor to ensure stable electrical contact between the conductor and the terminal, and another that slightly compresses the conductor to generate frictional force that resists tensile loads in the longitudinal direction of the conductor, thereby preventing breakage of the conductor. Therefore, the problem of ensuring electrical contact between the conductor and the terminal, and the problem of preventing the conductor from breaking and falling off the terminal can be solved simultaneously.

[0013] The first amount of crushing, which is the amount by which the conductor is crushed in the first clamping region, may be smaller than the second amount of crushing, which is the amount by which the conductor is crushed in the second clamping region.

[0014] The second clamping region may be a clamping region that ensures stable electrical contact between the conductor and the terminal. The first clamping region may also be a clamping region that generates a frictional force that resists a predetermined tensile load in the longitudinal direction of the conductor.

[0015] Further, the first compressing amount may be an amount that reduces the magnitude of the frictional force f2 [N] that resists a predetermined tensile load [N] in the longitudinal direction in the second clamping region by generating a frictional force f1 [N] that resists the predetermined tensile load in the longitudinal direction in the first clamping region, and makes the average stress σ2 [N / mm^2] in the cross section perpendicular to the longitudinal direction applied to the portion of the conductor part clamped in the second clamping region smaller than the tensile strength TS [N / mm^2] of the material of the conductor part.

[0016] When the magnitude of the predetermined tensile load F0 is 7 [N], the breakage of the conductor part in the second clamping region may be prevented by the average stress of the conductor part in the second clamping region being smaller than the tensile strength of the material of the conductor part.

[0017] The wire diameter d1 in the minor axis direction of the conductor part of the wire after being compressed by the first clamping region may satisfy the following conditional expression (1). d1≧0.21 [mm] (1)

[0018] The terminal is formed such that the first clamping region and the second clamping region are adjacent to each other in the direction in which the wire extends, and the length of the first clamping region in the direction in which the wire extends may be larger than the length of the first clamping region in the direction in which the wire extends.

[0019] The terminal is formed such that the first clamping region and the second clamping region are adjacent to each other in the direction in which the wire extends, and the length of the first clamping region in the direction in which the wire extends may be larger than the wire diameter of the wire before the wire is compressed.

[0020] The second compressing amount may be an amount that can ensure the conduction state between the wire and the terminal even after a heat shock test.

[0021] The second crushing amount Δd2 may satisfy the following conditional expression (2) when the wire diameter of the conductor portion of the wire before the wire is crushed is d0 and the wire diameter in the minor axis direction of the conductor portion of the wire at the second clamping portion after the wire is crushed is d2. Δd2 = d0 - d2 ≧ 0.15 [mm] (2)

[0022] The wire diameter d0 of the wire before the wire is crushed may satisfy the following conditional expression (3). 0.30 ≦ d0 ≦ 0.40 [mm] (3)

[0023] The terminal may have the first clamping regions arranged on both sides of the second clamping region in the direction in which the wire extends.

[0024] The terminal may have at least two or more of the second clamping regions arranged, and the first clamping region arranged between the two second clamping regions.

[0025] The terminal may be joined to the conductor portion of the wire by resistance welding and caulking.

[0026] The terminal may be formed of copper or a copper alloy.

[0027] The clamping portion has a folded-back portion formed by folding back a part of the terminal, a facing portion facing the folded-back portion, and a curved portion connecting the folded-back portion and the facing portion. In the second clamping region of the clamping portion, a protrusion is formed on the folded-back portion and a protrusion is formed on the facing portion, and the protrusion on the folded-back portion and the protrusion on the facing portion may face each other with the wire therebetween.

[0028] The protrusion formed on the curved portion is continuously formed with the protrusion formed on the folded-back portion and the protrusion formed on the facing portion, and may bite into the wire.

Advantages of the Invention

[0029] According to the present invention, when an aluminum wire is used as the conductor, it is possible to ensure electrical conductivity between the conductor and the terminal, and to prevent the conductor from breaking and falling off the terminal. [Brief explanation of the drawing]

[0030] [Figure 1] This is a top view showing the stator of an electric motor. [Figure 2] This diagram shows the state of the motor before the terminals are inserted into the stator. [Figure 3] This diagram shows the terminals inserted into the stator of the electric motor. [Figure 4] This is a perspective view of the terminal. [Figure 5] This is a front view showing the terminal clamping portion before it is bent. [Figure 6] These are front and side views showing the terminal clamping portion in a bent state. [Figure 7] This diagram shows the state in which the conductor is held in place by the clamping portion of the terminal. [Figure 8] This figure shows an example of a wire being crushed by a terminal. [Figure 9] This is a magnified view of the terminal clamping portion (Figure 7C). [Figure 10] This figure shows the clamping portion and conductor in a comparative example. [Figure 11] This figure shows the clamping portion and the conductor in this embodiment. [Figure 12] This graph shows the relationship between the thickness of the conductor and the tensile strength of the conductor. [Figure 13] This graph shows the amount of compression in the second stage of the heat shock test. [Modes for carrying out the invention]

[0031] Embodiments of the present invention will be described below with reference to the drawings.

[0032] Figure 1 is a top view showing the stator 100 of the electric motor. Figure 2 shows the state before the terminals 50 are inserted into the stator 100 of the electric motor. Figure 3 shows the state after the terminals 50 have been inserted into the stator 100 of the electric motor.

[0033] Figure 1A is a top view showing the stator 100 of the electric motor. As shown in Figure 1A, the stator 100 of the electric motor has a stator core 20 with a plurality of teeth 10, coils 30 wound around the teeth 10, and an insulator 40.

[0034] For example, the stator core 20 is formed in a cylindrical shape by laminating multiple plates made of a soft magnetic material, such as silicon steel sheets. The stator core 20 also has a yoke portion 21 and multiple teeth portions 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, 10-7, 10-8, 10-9, 10-10, 10-11, and 10-12. The yoke portion 21 is formed in a substantially cylindrical shape, and its central axis is positioned to overlap with the rotation axis 5 of the rotor (not shown). The teeth portion 10 is formed so that one end protrudes from the inner circumferential surface of the yoke portion toward the rotation axis 5 (radially inward). In this embodiment, the multiple teeth portions 10-1 to 10-12 are formed by arranging 12 of them at equal intervals in the circumferential direction on the inner circumferential surface of the yoke portion.

[0035] The radial direction refers to the direction of the diameter of a circle perpendicular to the axis of rotation 5, with the axis of rotation 5 as the center. The circumferential direction refers to the circumferential direction of a virtual circle with the axis of rotation 5 as the center.

[0036] The insulator 40 is fixed to the stator core 23 and has an outer wall portion 41, a plurality of wound copper portions 42-1, 42-2, 42-3, 42-4, 42-5, 42-6, 42-7, 42-8, 42-9, 42-10, 42-11, 42-12, and a plurality of flange portions 43-1, 43-2, 43-3, 43-4, 43-5, 43-6, 43-7, 43-8, 43-9, 43-10, 43-11, 43-12.

[0037] Multiple winding cylinder portions 42-1 to 42-12 are integrally formed on the outer wall portion 41 so as to protrude toward the rotation axis 5 from the inner circumferential surface of the outer wall portion 41, which is formed in a substantially cylindrical shape, and are arranged to be spaced equally apart in the circumferential direction. Multiple flange portions 43-1 to 43-12 correspond to the multiple winding cylinder portions 42-1 to 42-12, and each is formed in a substantially semicircular plate shape. Furthermore, multiple flange portions 43-1 to 43-12 are formed continuously at the inner diameter end of the multiple winding copper portions 42-1 to 42-12.

[0038] Furthermore, the multiple winding drum sections 42-1 to 42-12 correspond to the multiple tooth sections 10-1 to 10-12 of the stator core 23. In addition, 12 coils 30-1 to 30-12 are formed by winding a conductor 70 (winding) around each winding drum section 42 via the tooth section 10. In this embodiment, the coils 30-1 to 30-12 are arranged so that the order of U-phase, V-phase, and W-phase is repeated in the circumferential direction.

[0039] The insulator 40 also has a terminal block 45 into which terminals 50 are inserted on the outer wall portion 41. As shown in Figures 1 to 3, the terminal block 45a into which terminal 50a is inserted is provided between wound copper portion 42-1 and wound copper portion 42-12. The terminal block 45b into which terminal 50b is inserted is provided between wound copper portion 42-12 and wound copper portion 42-11. The terminal block 45c into which terminal 50c is inserted is provided between wound copper portion 42-11 and wound copper portion 42-10. The terminal block 45d into which terminal 50d is inserted is provided between wound copper portion 42-4 and wound copper portion 42-3. The terminal block 45e into which terminal 50e is inserted is provided between wound copper portion 42-2 and wound copper portion 42-1.

[0040] Terminal 50 is connected to a conductor 70 extending from coil 30. Terminal 50 is made of copper or a copper alloy (e.g., brass) and has a tin plating on its surface. Terminal 50 is held by the insulator 40 by being inserted into terminal block 45 (see Figures 2 and 3). The conductor 70 has a conductor portion 71 made of a conductor and an insulating coating portion 72 that covers the outer circumference of the conductor portion 71. In this embodiment, the conductor 70 is an aluminum wire in which the conductor portion 71 is made of aluminum or an aluminum alloy.

[0041] Figure 4 is a perspective view of terminal 50.

[0042] As shown in Figure 4, the terminal 50 has a connection portion 51 at one end that connects to a circuit board (not shown), an insertion portion 52 at the other end that is inserted into a terminal block 45, and a pair of protruding pieces 53 near one end of the insertion portion 52 for the terminal block 45 to hold the insertion portion 52. The terminal 50 also has a clamping portion 60 formed to protrude in the X direction of Figure 4 (the direction in which a perpendicular line is drawn from the vertex of the connection portion 51 to the bottom edge of the insertion portion 52). The clamping portion 60 is formed as a hook-shaped portion and clamps the conductor 70.

[0043] Figure 1B is a schematic diagram showing the connections between the terminals and the coil. Figure 1B is a diagram showing the coil 50 viewed from the inner circumference side (arrow A).

[0044] As shown in Figure 1B, one end of the conductor 70 drawn from coil 30-1 is held by the clamping portion (hook-shaped portion) 60 of terminal 50a so as to be clamped by the clamping portion 60. The other end of the conductor 70 drawn from coil 30-1 is connected to coils 30-10, 30-7, and 30-4. Furthermore, one end of the conductor 70 drawn from coil 30-4 is held by the clamping portion 60 of terminal 50d so as to be clamped by the clamping portion 60.

[0045] Similarly, one end of the conductor 70 drawn from coil 30-12 is held by the clamping portion 60 of terminal 50b so as to be clamped by the clamping portion 60. The other end of the conductor 70 drawn from coil 30-12 is connected to coil 30-9, coil 30-6, and coil 30-3. Furthermore, one end of the conductor 70 drawn from coil 30-3 is held by the clamping portion 60 of terminal 50d so as to be clamped by the clamping portion 60.

[0046] Furthermore, one end of the conductor 70 drawn from coil 30-11 is held by the clamping portion 60 of terminal 50c so as to be clamped by the clamping portion 60. The other end of the conductor 70 drawn from coil 30-11 is connected to coil 30-8, coil 30-5, and coil 30-2. In addition, one end of the conductor 70 drawn from coil 30-2 is held by the clamping portion 60 of terminal 50e so as to be clamped by the clamping portion 60.

[0047] One end of the conductor 70 drawn from the coil 30 is pulled inside the clamping portion 60 (hook-shaped portion) of the terminal 50 and joined to the terminal 50. In this embodiment, heat crimping is used as the method for joining the conductor 70 and the clamping portion 60 (hook-shaped portion). In heat crimping, resistance welding and crimping are performed simultaneously or continuously. In resistance welding, the clamping portion 60 of the terminal 50 is clamped together with one end of the conductor 70 by an electrode (not shown) for resistance welding, and current is applied to the electrode. At this time, the heat generated in the conductor 70 and terminal 50 due to the application of current to the electrode melts the insulating coating portion 72 covering the conductor portion 71 of the conductor 70 and the Sn plating plated on the outer surface of the terminal 50, exposing the conductor portion 71 of the conductor 70 and the metal portion of the terminal 50. Furthermore, by applying current to the electrodes, the conductor portion 71 of the conductor wire 70 and the clamping portion 60 of the metal terminal 50 are heated, making them more flexible (softer). In crimping, the conductor portion 71 and the clamping portion 60 (hook-shaped portion), which have become more flexible due to resistance welding, are joined by crimping (solid-state bonding).

[0048] Figure 5 is a front view showing the state of the terminal 50 before the clamping portion 60 is bent (before the hook-shaped portion is formed). Figure 5A is a front view of the terminal 50. Figure 5B is an enlarged view of the second clamping region 62. Figure 6 is a front view and a side view showing the state of the terminal 50 after the clamping portion 60 is bent (after the hook-shaped portion is formed).

[0049] As shown in Figure 5, the clamping portion 60 has a first clamping region 61 and a second clamping region 62. In this embodiment, the clamping portion 60 has three first clamping regions 61 (61a, 61b, 61c). In this embodiment, it also has two second clamping regions 62 (62a, 62b). In this embodiment, the clamping portion 60 has the first clamping regions 61 and the second clamping regions 62 arranged alternately in the longitudinal direction (X direction) of the extending wire 70.

[0050] As shown in Figure 5B, the second clamping region 62 has a projection 63 that compresses the conductor 70 more than the first clamping region 61. Here, the second clamping region 62 is defined as the clamping region 60 in the length direction (X direction) of the conductor 70 where the projection 63 is formed. In other words, the second clamping region 62 compresses the conductor 70 more than the first clamping region 61 by the height of the projection 63 and holds the conductor 70. To put it another way, the first compression amount Δd1, which is the amount by which the conductor 70 (conductor portion 71) is compressed in the first clamping region 61, is smaller than the second compression amount Δd2, which is the amount by which the conductor 70 (conductor portion 71) is compressed in the second clamping region 62, satisfying Δd1 < Δd2.

[0051] In this embodiment, the second clamping region 62 of the clamping portion 60 functions as a clamping region that stably connects the conductor 70 and the terminal 50. Furthermore, the first clamping region 61 of the clamping portion 60 functions as a clamping region that reduces the magnitude of stress generated in the second clamping region 62 by generating a frictional force in the first clamping region 61 that resists a predetermined tensile load in the longitudinal direction of the conductor 70, thereby preventing the conductor portion 71 of the conductor 70 from breaking in the second clamping region.

[0052] For the first clamping region 61 to function as a region that prevents the conductor portion 71 from breaking in the second clamping region 62, the average stress σ2 generated in the conductor portion 71 clamped in the second clamping region 61, where the conductor portion 71 is most compressed and therefore most prone to breaking, must be smaller than the tensile strength Rm of the aluminum wire (the maximum stress generated before the aluminum wire breaks when pulled to the point of breakage). Note that the tensile strength Rm is an inherent value determined by the material properties, regardless of the shape of the conductor or the magnitude of the force pulling the conductor. Details of the mechanism by which the first clamping region 61 functions as a region that prevents the conductor portion 71 from breaking in the second clamping region 62 in this embodiment will be described later.

[0053] A portion of the terminal 50 (the clamping portion 60) is folded back from the terminal 50 before the hook-shaped portion shown in Figure 5 is formed, thereby creating the terminal 50 having the hook-shaped portion shown in Figure 6. Figure 6A is a front view of the terminal 50. Figure 6B is a side view of the terminal 50.

[0054] As shown in Figure 6, the clamping portion 60 (hook-shaped portion) of the terminal 50 comprises a folded portion 64 formed by folding back a part of the terminal 50, an opposing portion 65 facing the folded portion 64, and a curved portion 66 connecting the folded portion 64 and the opposing portion 65. Also, as shown in Figures 5 and 6, the projection 63 formed on the clamping portion 60 is formed continuously across the folded portion 64, the opposing portion 65, and the curved portion 66.

[0055] Figure 7 shows the state in which the conductor 70 is held by the clamping portion 60 (hook-shaped portion) of the terminal 50. Figure 7A is a front view of the terminal 50 in the state in which the conductor 70 is held. Figure 7B is a side view of the terminal 50 in the state in which the conductor 70 is held. Figure 7C is a cross-sectional view taken along line A-A' in Figure 7A.

[0056] As shown in Figure 7, the first clamping region 61 and the second clamping region 62 are arranged to be aligned in the direction in which the conductor 70 extends (see the X direction in Figure 5) at the portion clamped by the clamping portion 60. In the second clamping region 62, the projection 63 formed on the folded portion 64 and the projection 63 formed on the opposing portion 65 face each other with the conductor 70 in between. Also, as shown in Figure 7B, the projection 60 formed on the curved portion 66 is formed to bite into the conductor 70.

[0057] As shown in Figure 7C, the terminal 50 has first clamping regions 61 positioned on both sides of the second clamping region 62 in the direction in which the conductor 70 extends. For example, in this embodiment, the first clamping region 61a is positioned on one side of the second clamping region 62a, and the first clamping region 61b is positioned on the other side of the second clamping region 61a. In addition, the terminal 50 has two or more second clamping regions 62 positioned in the direction in which the conductor 70 extends, with the first clamping region 61 positioned between two second clamping regions 62. For example, in this embodiment, the first clamping region 61b is positioned between the second clamping regions 62a and 62b.

[0058] Here, let d0 [mm] be the original wire diameter of the conductor portion 71 of the conductor wire 70 (aluminum wire) (the wire diameter of the conductor portion 71 of the conductor wire before heat crimping) (see Figure 9). Note that d0 may be the design dimension of the conductor portion of the aluminum wire. For example, in this embodiment, the wire diameter d0 of the conductor wire 70 before crushing is 0.30 ≤ d0 ≤ 0.40 [mm].

[0059] Furthermore, let d1 be the thickness of the aluminum wire remaining after the conductor portion 71 of the conductor wire 70 has been crushed by the first clamping region 61 after heat crimping (the wire diameter in the short axis direction of the conductor portion 71 of the conductor wire 70 after being crushed by the first clamping region 61) (see Figure 9). Also, let d2 be the thickness of the aluminum wire remaining after the conductor portion 71 of the conductor wire 70 has been crushed by the second clamping region 62 after heat crimping (the wire diameter in the short axis direction of the conductor portion 71 of the conductor wire 70 after being crushed by the second clamping region 62) (see Figure 9). Note that the short axis direction here refers to the direction in which the diameter is smallest in the cross-section of the conductor portion 71 of the conductor wire 70 after being crushed (a cross-section perpendicular to the direction in which the conductor wire 70 extends), and is not limited to the case where the shape of the conductor portion 71 is elliptical. For example, the wire diameter d1 in the short axis direction of the conductor portion 71 of the conductor wire shown in Figure 8 is represented by diameter 711.

[0060] Furthermore, d3 is defined as the thickness of the conductor portion 71 of the aluminum wire that remains after the conductor portion 71 of the conductor wire 70 is crushed by the region positioned between the first clamping regions 61 after heat crimping. Ideally, when the terminal 50 is bent, the folded portion 64 and the opposing portion 65 can be formed parallel to each other, so d1 and d3 are the same value. However, in actual formation, the area of ​​d1, i.e., both ends of the clamping portion 60, tends to open slightly, so d1 > d3. For this reason, in this embodiment, d1 and d3 are expressed separately.

[0061] The thicknesses (wire diameter in the short axis direction) d1, d2, and d3 of the conductor portion 71 of the aluminum wire after it has been crushed correspond to the length 711 (see double arrow indicating the diameter 711 on the short axis side of the conductor portion 711) in the direction in which the conductor portion of the wire shown in Figure 8 (see dashed line 71) is crushed between the folded portion 64 and the opposing portion 65 (the direction of the plate thickness of the opposing portion 65). In other words, the length of the short axis 711 when the circular conductor portion 71 of the aluminum wire is crushed from a predetermined direction to become elliptical can also be said to be the thicknesses d1, d2, and d3 of the conductor portion 71 of the aluminum wire. Figure 8 is a magnified photograph of the clamping portion 60 and the conductor 70 of the embodiment after heat crimping, and since the coating portion 72 of the conductor 70 has melted and disappeared due to the heat of resistance welding, only the conductor portion 71 remains.

[0062] Furthermore, as shown in Figure 7, the first clamping region 61 and the second clamping region 62 are arranged adjacent to each other in the direction in which the conductor 70 extends. It is desirable that the length of the first clamping region 61 in the direction in which the conductor 70 extends is greater than the wire diameter d0 of the conductor portion 71 before the conductor 70 is crushed.

[0063] For example, in terminal 50 of Figure 6A, the length L0 of the clamping portion 60 (hook-shaped portion) of terminal 50 in the direction in which the conductor 70 extends (X direction) is 3 mm, the length L1 of the first clamping region 61a and the length L3 of the third clamping region 61c in the X direction are both 0.85 mm, the length L (width of the projection 63) of the two second clamping regions 62 (62a, 62b) in the X direction is both 0.3 mm, and the length of the first clamping region 61b in the X direction (distance between the two second clamping regions 62) is 0.7 mm. In other words, in this embodiment, the lengths L1 (L1a, L1b, L1c) of the first clamping regions 61 (61a, 61b, 61c) formed to be continuous with the second clamping region 62 are all greater than the wire diameter d0 (0.30~0.40 mm) of the conductor portion 71 of the conductor 70 before it is crushed.

[0064] More preferably, the lengths of the first clamping regions 61a and 61c, which are continuous on one side with the second clamping region 62 and exposed from the clamping portion 60 (hook-shaped portion) on the other side, in the X direction, are preferably at least twice the wire diameter d0 of the conductor portion 71 of the conductor 70 before it is crushed. When the conductor 70 is made of aluminum wire, the restoring force of the conductor portion 71 of the conductor 70 is weak. If the conductor portion 71 of the conductor 70 (aluminum wire), which has been greatly crushed in the second clamping region 62, does not return to a certain thickness in the first clamping region 61 which is continuous with the second clamping region 62, the area in which the conductor portion 71 contacts (fits tightly) with the clamping portion 60 in the first clamping region 61 cannot be increased, and sufficient frictional force to resist the tensile load in the longitudinal direction of the conductor 70 cannot be generated in the first clamping region 61. Therefore, in this embodiment, the length of the first clamping region 61 in the X direction is set to at least twice the wire diameter d0 of the conductor portion 71 of the conductor 70 before it is crushed. As a result, as shown in Figure 9, the length of the first clamping region 61 is sufficiently long, so that the conductor portion 71 of the conductor 70, which has been greatly crushed in the second clamping region 62, gradually approaches the thickness of the conductor portion 71 before it was crushed by the restoring force before it reaches the position where it is exposed from the clamping portion 60 (hook-shaped portion). This increases the area in which the conductor portion 71 contacts (closely adheres to) the terminal 50 (clamping portion 60) in the first clamping region 61, thereby generating sufficient frictional force in the first clamping region 61 and effectively preventing the conductor portion 71 of the conductor 70 from breaking. In this embodiment, the first clamping regions 61a and 61c, which are formed to be continuous with the second clamping region 62, are larger than twice the wire diameter d0 (0.30 to 0.40 mm) of the conductor portion 71 of the conductor 70 before it is crushed.

[0065] Of course, the numerical values ​​of each part in the direction in which the conductor 70 of terminal 50 extends are not limited to those described above. For example, the length of the first clamping region 61 in the X direction should be such that it functions as a region that prevents the conductor 71 from breaking by generating frictional force when the conductor portion 71, which has been greatly crushed by the second clamping region 62, returns to a certain thickness and comes into contact with terminal 50 in the first clamping region 61. For example, the length of the first clamping region 61 in the X direction may be set based on the restoring force of the conductor according to the composition of the aluminum alloy used for the conductor 70.

[0066] Furthermore, the number and arrangement order of the first clamping regions 61 and the second clamping regions 62 in the clamping portion 60 are not limited. For example, as shown in Figure 6A, in addition to the arrangement of first clamping region 61, second clamping region 62, first clamping region 61, second clamping region 62, and first clamping region 61 in order from the X direction, a region that maintains the thickness of the conductor 70 at d0 (a region that does not crush the aluminum wire) may be formed between the two second clamping regions 62.

[0067] Here, we define the amount of crushing, which is the amount by which the aluminum wire is crushed in the clamping portion 60 by crimping. The first crushing amount Δd1, which is the amount by which the conductor is crushed in the first clamping region 61, is the difference between d0 and d1 (Δd1 = d0 - d1). The second crushing amount Δd2, which is the amount by which the conductor is crushed in the second clamping region 62, is the difference between d0 and d2 (Δd2 = d0 - d2).

[0068] Furthermore, as shown in Figures 5B and 7C, the second clamping region 62 has a projection 63, so the wire can be compressed more than in the first clamping region by the height of the projection. That is, the relationship d1 > d2 holds for the thickness of the aluminum wire after compression. Moreover, the first compression amount Δd1, which is the amount by which the wire is compressed in the first clamping region 61, is smaller than the second compression amount Δd2, which is the amount by which the wire is compressed in the second clamping region 62.

[0069] The first crushing amount Δd1 should be such that it is sufficient to withstand a predetermined tensile load F0 [N] and prevent the conductor from breaking. In this embodiment, the predetermined tensile load F0 is defined as the load when it is assumed that a stress equal in magnitude to the tensile strength (maximum stress generated before breakage) TS [N / mm^2 = MPa] of the aluminum material of the conductor portion 71 of the aluminum wire (conductor 70) is applied to the entire cross-sectional area (1 / 4 × π × D^2) of the conductor portion 71. In this embodiment, TS = 78 [MPa] and D = 0.3 [mm], and the tensile load F ≈ 7 [N*] at this time.

[0070] Next, the mechanism of stress generation (normal stress) in the first clamping region 61 and the second clamping region 62 under tension will be explained. For the sake of simplicity, in this embodiment, the clamping portion 60 is assumed to have one first clamping region 61 with length L1 and one second clamping region 62 with length L2. In the comparative example, the clamping portion 60 is assumed to have only one second clamping region 62 with length L2 and no first clamping region 61. In both the comparative example and this embodiment, the diameter of the conductor portion 71 of the conductor 70 in the short axis direction after being crushed in the second clamping region 62 is assumed to be d2 [mm]. Also, the magnitude of the tensile load F0 applied to the conductor 70 is assumed to be the same in both this embodiment and the comparative example.

[0071] Figure 10 shows the clamping portion 60 and the conductor 70 in the comparative example. Figure 10A shows the clamping portion 60 and the conductor 70 in the comparative example. Figure 10B shows the FBD (Free Body Diagram) of the second clamping region 62 in the comparative example.

[0072] As shown in Figures 10A and 10B, if the clamping portion 60 does not have a first clamping region 61 (or the first clamping region 61 is short), as in the comparative example, the frictional force F2b generated in the second clamping region 62 must balance the tensile load F0 (F2b ≈ F0). Therefore, the stress σ2b [N / mm^2] generated in the second clamping region 62 in the comparative example can be expressed as σ2b = F2b / A2, where A2 [mm^2] is the cross-sectional area of ​​the conductor portion 71 in the second clamping region 62. Here, assuming that the cross-sectional area of ​​the conductor portion 71 does not change significantly before (let's call it A0 [mm^2]) and after it is crushed, A2 ≈ A0 = (1 / 4) × π × d0^2. Thus, σ2b ≈ F0 / A0. Because this stress σ2b tends to be greater than the tensile strength TS of the aluminum material of the conductor 70 (σ2b > TS), there was a problem that fracture was likely to occur in the second clamping region 62.

[0073] FIG. 11 is a diagram showing the clamping portion 60 and the conducting wire 70 in the present embodiment. FIG. 10A is a diagram showing the clamping portion 60 and the conducting wire 70 in the present embodiment. FIG. 10B is a diagram showing the FBD of the first clamping region 61 in the present embodiment. FIG. 10C is a diagram showing the FBD of the second clamping region 62 in the present embodiment.

[0074] In contrast, in the present embodiment shown in FIGS. 11A to 11C, since the clamping portion 60 includes the first clamping region 61, a frictional force is generated between the clamping portion 60 and the conductor portion 71 not only in the second clamping region 62 but also in the first clamping region 61. Therefore, when the frictional force generated in the first clamping region 61 in the present embodiment is F1a [N] and the frictional force generated in the second clamping region 62 is F2a [N], the sum of these frictional forces needs to balance the tensile load F0, that is, F1a + F2a = F0. Assuming that the cross-sectional area of the conductor portion 71 does not change significantly before and after being crushed, if the cross-sectional area of the conductor portion 71 in the first clamping region is A1 [mm^2], then A2 ≈ A1 ≈ A0 = (1 / 4) × π × d0^2. Here, since F1a > 0 and F2a > 0, from F1a + F2a = F2b, it can be said that F1a < F2b and F2a < F2b.

[0075] Therefore, the stress σ1a [N / mm^2] generated in the first clamping region 61 in the present embodiment satisfies σ1a = F1a / A1 ≈ F1a / A0 < F2b / A0 = σ2b. Similarly, the stress σ2a [N / mm^2] generated in the second clamping region 62 in the present embodiment satisfies σ2a = F2a / A2 ≈ F2a / A0 < F2b / A0 = σ2b. From the above, the stress σ1a generated in the first clamping region 61 in the present embodiment is smaller than the stress σ2b generated in the second clamping region 62 in the comparative example. Similarly, the stress σ2a generated in the second clamping region 62 in the present embodiment is smaller than the stress σ2b generated in the second clamping region 62 in the comparative example. Therefore, in the present embodiment, since both the stress σ1a and the stress σ2a are likely to be smaller than the tensile strength TS of aluminum, which is the material of the conducting wire 70 (satisfying σ1a < TS and σ2a < TS), it is possible to prevent breakage in the second clamping region 62 where a large stress is likely to be generated in the conductor portion 71 due to a large amount of crushing.

[0076] In this embodiment, the magnitude of the frictional force generated in the first clamping region 61 and the second clamping region 62 increases as the amount of compression of the conductor portion 71 in each region increases, and decreases as the amount of compression of the conductor portion 71 in each region decreases. In this embodiment, the first compression amount Δd1, which is the amount of compression of the conductor portion 71 in the first clamping region 61, is smaller than the second compression amount Δd2, which is the amount of compression of the conductor portion 71 in the second clamping region 62. Therefore, the frictional force F1 generated in the first clamping region 61 to resist the tensile load F0 is reduced. Accordingly, in this embodiment, the length L1 (L1a, L1b, L1c) of the first clamping region 61 in the longitudinal direction of the conductor 60 is made longer than the length L2 (L2a, L2b) of the second clamping region 62. This increases the magnitude of the frictional force F1a against the tensile load generated in the first clamping region 61, decreases the frictional force F2a generated in the second clamping region 62, and as a result, reduces the stress σ2a generated in the second clamping region 62 under tension.

[0077] Furthermore, when an aluminum wire is used as the conductor 70, since aluminum wire has weaker restoring force against deformation compared to copper wire, if the conductor portion 71 of the conductor 70 (aluminum wire), which is greatly crushed in the second clamping region 62, does not return to a certain thickness in the first clamping region 61 which is continuous with the second clamping region 62, the area in which the conductor portion 71 contacts (fits tightly) with the clamping portion 60 in the first clamping region 61 cannot be increased, and sufficient frictional force to resist the tensile load in the longitudinal direction of the conductor 70 cannot be generated in the first clamping region 61. Therefore, in this embodiment, the length L1 (L1a, L1b, L1c) of each of the three first clamping regions 61 (61a, 61b, 61c) is made larger than the wire diameter d0 before the conductor portion 71 was crushed (i.e., L1a>d0, L1b>d0, L1c>d0). This allows the length L1 of the first clamping region 61 to be made sufficiently long. Even if the conductor 70 is an aluminum wire with weak restoring force, the thickness of the conductor portion 71 of the conductor 70, which has been greatly crushed in the second clamping region 62, can return to a thickness that provides sufficient frictional force with the terminal 50 before reaching the position where it is exposed from the clamping portion 60 (hook-shaped portion). This allows sufficient frictional force to resist the tensile load in the longitudinal direction of the conductor 70 to be generated in the first clamping region 61.

[0078] Figure 12 is a graph showing the relationship between the thickness (length in the short axis direction) d1 of the conductor portion 71 of the conductor (aluminum wire) 70 after it has been crushed by the clamping portion 60, and the tensile load applied when the conductor finally breaks (hereafter also referred to as the breaking load FL) as the tensile load is gradually increased during a tensile test of the conductor 70 in a state where it has been crushed by the clamping portion 60. In Figure 12, the horizontal axis shows the thickness d1 of the conductor portion 71 of the aluminum wire after it has been crushed by the clamping portion 60, and the vertical axis shows the breaking load FL. Figure 12A is a graph showing the case when the thickness d0 of the aluminum wire before crushing is 0.3 mm. Figure 12B is a graph showing the case when the thickness d0 of the aluminum wire before crushing is 0.35 mm. Figure 12C is a graph showing the case when the thickness d0 of the aluminum wire before crushing is 0.40 mm.

[0079] In the tensile test, it is determined whether the breaking load FL, which is the maximum tensile load that the conductor portion 71 can withstand without breaking after being crushed by the clamping portion 60, is greater than a predetermined reference load FR. In other words, if the breaking load FL is greater than the reference load FR, the conductor portion 71 will not break even if the predetermined reference load FR is applied. In this embodiment, the reference load FR is the tensile load that may be applied to the conductor 70 during the manufacturing process in which the conductor 70 is clamped by the clamping portion 60, and FR = 7 [N].

[0080] (Assuming that a stress equal in magnitude to the tensile strength of the aluminum material of the conductor part 71 (the maximum stress generated when the material is subjected to tension until it breaks) TS [N / mm^2 = MPa] is applied to the entire cross-sectional area (1 / 4 × π × D^2) of the conductor part 71 before it is crushed, the standard load FR, which is a predetermined tensile load, is defined as FR = TS × (1 / 4 × π × D^2). In this embodiment, TS = 78 [MPa] and D = d0 = 0.3 [mm], in which case the standard load FR ≈ 7 [N].)

[0081] As shown in Figure 12A, in order to withstand a tensile load of 7N, which is the standard load (to prevent fracture when the tensile load is the standard load), it is necessary to flatten the aluminum wire so that the thickness of the conductor portion 71 remains at least 0.21 mm (satisfying the condition d1 > 0.21 [mm]). In other words, if the aluminum wire is flattened too much and the thickness of the conductor portion 71 after flattening (length in the short axis direction) d1 falls below 0.21 mm, the tensile load that can be withstood without fracture (breaking load) becomes smaller than the standard load, and there is a possibility that it will break.

[0082] Furthermore, Figure 12B shows that even when the thickness d0 of the aluminum wire before crushing is 0.35 mm, crushing the aluminum wire so that a thickness of 0.21 mm or more remains (satisfying d1 > 0.21 [mm]) prevents it from breaking even when a tensile load of 7 N, the standard load in this embodiment, is applied. Similarly, Figure 12C shows that even when the thickness d0 of the aluminum wire before crushing is 0.40 mm, crushing the aluminum wire so that a thickness of 0.21 mm or more remains (satisfying d1 > 0.21 [mm]) prevents it from breaking even when a tensile load of 7 N, the standard load, is applied.

[0083] Based on the above, it is preferable that the wire diameter d1 in the short axis direction of the conductor portion 71 of the conductor 70 after it has been crushed by the first clamping portion 61 satisfies the following equation. d1≧0.21mm

[0084] As a result, the wire diameter of the conductor portion 71 of the conductor 70 remaining after being crushed in the first clamping area 61 is 0.21 mm or more (satisfying d1 > 0.21 [mm]), which prevents the conductor portion 71 from breaking when a predetermined tensile load (reference load) is applied, and prevents the conductor from falling out of the clamping portion 60.

[0085] Furthermore, in this embodiment, the second compression amount Δd2 is such that electrical conductivity between the conductor 70 and the terminal 50 is ensured even after the heat shock test.

[0086] Figure 13 is a graph showing the results of a heat shock test based on the difference in the second compression amount Δd2. A heat shock test is a test to confirm the resistance to temperature changes by repeatedly applying high temperatures (e.g., 60 to 90°C) and low temperatures (e.g., 0 to -30°C) to the object being tested for a short period of time (e.g., a few minutes). Here, the results of an air chamber heat shock test are shown. In the graph in Figure 13, the horizontal axis shows the compression amount Δd2 of the conductor portion 71 of the aluminum wire, and the vertical axis shows whether the conductivity state after the heat shock test is good or bad. Here, "good" in Figure 13 means that the contact of the conductor is good after the heat shock test (low contact resistance (e.g., less than 20 mΩ)), that is, the conductivity state is stably maintained. Also, "bad" in Figure 13 means that the contact of the conductor is poor after the heat shock test (high contact resistance (e.g., 20 mΩ or more)), that is, the conductivity state is unstable.

[0087] Figure 13A is a graph showing the results of a heat shock test when the second crushing amount Δd2 is varied, with the thickness d0 of the aluminum wire before crushing being 0.3 mm. Figure 13B is a graph showing the results of a heat shock test when the second crushing amount Δd2 is varied, with the thickness d0 of the aluminum wire before crushing being 0.35 mm. Figure 13C is a graph showing the results of a heat shock test when the second crushing amount Δd2 is varied, with the thickness d0 of the aluminum wire before crushing being 0.40 mm.

[0088] Note that the heat shock test shown in Figure 13 uses two aluminum wires joined together (two-wire joint), as shown in Figure 7B. Also, as shown in Figure 7B, the base wire in the two-wire joint is designated as conductor 70a, and the tip wire is designated as conductor 70b, and these two wires are distinguished and described separately.

[0089] Figure 13A illustrates the following: "No protrusion," which is a flat terminal with only a second clamping area 62, meaning the conductor 70 is always crushed by a second crushing amount Δd2; "Condition 2: Root side (protrusion 0.03mm)," which is the conductor 70a at the root and the conductor 70b at the tip, when the protrusion of the second clamping area 62 (see protrusion height in Figure 5B) is 0.03mm; "Condition 2: Root side (protrusion 0.06mm)," which is the conductor 70a at the root and the conductor 70b at the tip, when the protrusion of the second clamping area 62 is 0.06mm; and "Condition 3: Root side," which is the conductor 70a at the root and the conductor 70b at the tip, when the protrusion of the second clamping area 62 is 0.06mm.

[0090] Figure 13B also illustrates "Condition 4: Root side," which is the conductor 70a on the root side when the thickness d0 of the aluminum wire before crushing is 0.35 mm and the size of the protrusion of the second clamping region 62 is 0.06 mm. Figure 13C also illustrates "Condition 4: Root side," which is the conductor 70b on the root side when the thickness d0 of the aluminum wire before crushing is 0.40 mm and the protrusion of the second clamping region 62 is 0.06 mm. Figure 13B also shows the results of a heat shock test when the length in the Y direction of the second clamping region 62 before the clamping portion 60 is bent is 3.9 mm, as shown in Figure 5. Figure 13C also shows the results of a heat shock test when the length in the Y direction of the second clamping region 62 before the clamping portion 60 is bent is 4.3 mm, as shown in Figure 5. The length of the second clamping area 62 in the Y direction is not limited; it is sufficient if it is long enough to securely clamp both sides of the aluminum wire (conductor 70) even if there are two of them.

[0091] As shown in Figures 13A to C, under the various conditions described above, if the amount of compression in the second clamping region 62 exceeds 0.15 mm, it can be seen that the electrical conductivity between the conductor portion 70 of the conductor 70 and the terminal 50 is stably maintained and good contact is achieved even after the heat shock test.

[0092] Based on the above, if d2 is the diameter of the conductor portion 71 of the conductor 70 in the second clamping region 62 after the conductor 70 has been crushed by the second clamping region 62, then it is preferable that the second crushing amount Δd2, which is the amount of crushing in the second clamping region 62, satisfies the following equation. Δd2 = d0 - d2 ≥ 0.15 mm

[0093] As a result, the amount of compression in the second clamping region 62 exceeds 0.15 mm, which makes it possible to maintain electrical conductivity between the conductor portion 71 of the conductor 70 and the terminal 50 even after the heat shock test, regardless of the wire diameter of the conductor portion 71 of the conductor 70.

[0094] As described above, according to this embodiment, in an electric motor 100 comprising a stator core 20 having a plurality of teeth 10, a coil 30 wound around the teeth 10, and a terminal 50 to which a conductor 70 extending from the coil 30 is connected, the conductor 70 is an aluminum wire whose conductor portion 71 is made of aluminum or an aluminum alloy, the terminal 50 has a clamping portion 60 that clamps the conductor 70, the clamping portion 60 has a first clamping region 61 and a second clamping region 62, the amount of crushing of the conductor portion 71 of the conductor 70 in the first clamping region 61 and the amount of crushing of the conductor portion 71 of the conductor 70 in the second clamping region 62 are different from each other, and the first clamping region 61 and the second clamping region 62 are arranged side by side in the direction in which the conductor 70 extends in the portion clamped by the clamping portion 60. This allows the terminal 50 to have two distinct regions along the length of the conductor: a region where the conductor 70 is significantly compressed to ensure stable electrical contact between the conductor portion 71 and the terminal 50 (e.g., a second clamping region 62), and a region where the conductor 70 is slightly compressed to generate a frictional force that resists a predetermined tensile load in the direction in which the conductor 70 extends, thereby reducing the stress generated in the second clamping region 62 (e.g., a first clamping region 61). This ensures electrical contact between the conductor portion 71 of the conductor 70 and the terminal 50, while also preventing the conductor 70 from falling off the terminal 50 (due to breakage of the conductor portion 71).

[0095] Here, as a first comparative example, if the entire clamping portion 60 consists only of a clamping region where the amount of compression of the conductor portion of the wire is small (corresponding to the first clamping region 61 in this embodiment), the expansion and contraction before and after heat crimping may result in insufficient contact between the conductor portion and the terminal 50, and there is a risk that the conductive state may not be stably maintained.

[0096] Furthermore, as a second comparative example, if the entire clamping portion 60 consists only of a clamping region where the amount of compression of the conductor portion of the conductor is large (a region corresponding to the second clamping region 62), stress will concentrate near the boundary between the portion of the conductor held by the clamping portion 60 and the other portions. This will cause the stress generated in the conductor portion to exceed the material's inherent tensile strength (the maximum stress it can withstand without breaking), leading to increased strain and ultimately the risk of fracture.

[0097] In contrast, in this embodiment, a second clamping region 62 that stably connects the conductor portion 71 of the conductor 70 with the terminal 50, and a first clamping region 61 that prevents the conductor portion from breaking in the second clamping region are provided, separated in the direction in which the conductor 70 extends, and the first clamping region 61 and the second clamping region 62 are arranged side by side, thereby stably maintaining the electrical connection between the conductor portion 71 and the terminal 50, and preventing the conductor 70 from falling off the terminal 50.

[0098] Furthermore, according to this embodiment, the first crushing amount Δd1, which is the amount by which the conductor portion 71 of the conductor 70 is crushed in the first clamping region 61, is smaller than the second crushing amount Δd2, which is the amount by which the conductor 70 is crushed in the second clamping region 62. This ensures electrical conductivity by increasing the amount of crushing of the conductor 70 in the second clamping region 62 (by making the second crushing amount Δd2 > the first crushing amount Δd1), while preventing the conductor portion 71 from breaking in the second clamping region 62 by decreasing the amount of crushing of the conductor 70 in the first clamping region 61 (by making the first crushing amount Δd1 < the second crushing amount Δd2).

[0099] Furthermore, according to this embodiment, the first compression amount Δd1 generates a frictional force f1 [N] in the first clamping region 61 that resists a predetermined tensile load in the longitudinal direction of the conductor 70, thereby reducing the magnitude of the frictional force f2 [N] that resists the tensile load generated in the second clamping region, and the mean stress σ2 [N / mm] in the cross section perpendicular to the longitudinal direction applied to the conductor portion 71 of the part clamped in the second clamping region. 2 ] is the tensile strength TS [N / mm²] of aluminum, which is the material of the conductor part 71. 2 This is the amount of compression to be smaller than ]. This makes it possible to set the first compression amount Δd1 to an amount of compression that prevents the conductor portion 71 of the conductor 70 from breaking.

[0100] Furthermore, according to this embodiment, when the magnitude of a predetermined tensile load F0 is 7 [N], the average stress σ2 [N / mm] of the conductor portion 71 in the second clamping region 62 is 2 ] is the tensile strength TS [N / mm²] of aluminum, which is the material of the conductor part 71. 2This is smaller than ]. As a result, even if a tensile load that may be applied to the conductor 70 during the manufacturing process in which the conductor 70 is clamped by the clamping portion 60 is applied to the conductor 70, it is possible to prevent the conductor portion 71 from breaking in the second clamping region 62, where the conductor portion 71 is prone to breaking.

[0101] Furthermore, according to this embodiment, the wire diameter d1 on the minor axis side of the conductor portion 71 of the conductor 70 after it has been crushed by the first clamping region 61 satisfies the following condition (1). d1≧0.21[mm] (1) As a result, in the first clamping region 61, the diameter of the short axis side of the conductor portion 71 of the conductor 70 remaining after crushing is 0.21 mm or more, resulting in an average stress σ1 [N / mm²] in the cross section perpendicular to the longitudinal direction of the conductor portion 71 after crushing in the first clamping region 61. 2 ] is the tensile strength TS[N / mm²] of aluminum, which is the material of the conductor part 71. 2 This prevents the clamping force from becoming larger than the first clamping region 61, while still generating frictional force between the clamping region 61 and the conductor portion 71. Therefore, it is possible to prevent breakage due to tension in the first clamping region 61 and to prevent breakage due to tension in the second clamping region 62, thereby preventing the conductor from falling out in the first clamping region 61.

[0102] Furthermore, according to this embodiment, the length L1 (L1a, L1b, L1c) of the first clamping region 61 in the longitudinal direction of the conductor 60 is made longer than the length L2 (L2a, L2b) of the second clamping region 62. This increases the magnitude of the frictional force F1 against the tensile load generated in the first clamping region 61, decreases the frictional force F2 generated in the second clamping region 62, and as a result, the mean stress σ2 generated in the second clamping region 62 under tension can be reduced.

[0103] Furthermore, according to this embodiment, the terminal 50 is formed such that the first clamping region 61 and the second clamping region 62 are adjacent to each other in the direction in which the conductor 70 extends, and the length L1 of the first clamping region 61 in the direction in which the conductor 70 extends is greater than the wire diameter d0 of the conductor portion 71 of the conductor 70 before the conductor 70 is crushed. When aluminum wire is used as the conductor 70, aluminum wire has weaker restoring force against deformation compared to copper wire. In particular, when the first clamping region 61 is formed continuously with the second clamping region 62, the length L1 of the first clamping region 61 in the direction in which the conductor portion 71 of the conductor 70 (aluminum wire), which has been greatly crushed in the second clamping region 62, returns to a certain thickness in the first clamping region 61. This generates sufficient frictional force for the first clamping region 61 to resist tension, thereby weakening the stress generated in the second clamping region 62 and preventing breakage in the second clamping region 62. In this case, the length L1 of the first clamping region 61 in the direction in which the conductor 70 extends must be made to a certain extent. Therefore, by making the length L1 of the first clamping region 61 greater than or equal to the diameter d0 of the conductor portion 71 of the conductor 70 before it is crushed in the longitudinal direction of the conductor 70, the conductor portion 71 of the conductor 70 that has been greatly crushed in the second clamping region 62 can return to a certain thickness in the first clamping region 61, and a region can be reliably obtained in which the conductor 70 can be held while preventing breakage of the conductor portion 71.

[0104] Furthermore, according to this embodiment, the second compression amount Δd2 is such that the electrical conductivity between the conductor portion 71 of the wire 70 and the terminal 50 is ensured even after the heat shock test. This ensures that the electrical conductivity between the conductor portion 71 of the wire 70 and the terminal 50 is reliably maintained in the second clamping region 62.

[0105] Furthermore, according to this embodiment, the second crushing amount Δd2 satisfies the following condition (2), where d0 is the wire diameter of the conductor portion 71 of the conductor 70 before the conductor 70 is crushed, and d2 is the wire diameter of the conductor portion 71 of the conductor 70 in the second clamping region 62 after the conductor 70 is crushed. Δd2 = d0 - d2 ≥ 0.15 [mm] (2) As a result, the amount of compression in the second clamping region 62 exceeds 0.15 mm, which is sufficient to ensure electrical contact between the conductor portion 71 of the conductor and the terminal 50 in the second clamping region 62, regardless of the diameter of the conductor 70.

[0106] Furthermore, according to this embodiment, the wire diameter d0 of the conductor 70 before it is crushed satisfies the following condition (3). 0.30 ≤ d0 ≤ 0.40 [mm] (3) This makes it possible to secure a wire diameter d0 that satisfies both a first crushing amount that prevents the conductor from falling out in the first clamping region 61 and a second crushing amount that ensures electrical conductivity in the second clamping region 62.

[0107] Furthermore, according to this embodiment, the terminal 50 has first clamping regions 61 positioned on both sides of the second clamping region 62 in the direction in which the conductor 70 extends. As a result, no matter which direction in which the tensile load is applied to the conductor 70, a frictional force resisting the tensile load can be generated in the first clamping region 61 adjacent to the second clamping region 62 in the direction in which the tensile load is applied. This reduces the average stress σ2 generated in the second clamping region 62, and prevents the conductor portion 71 from breaking in the second clamping region 62 while maintaining electrical conductivity between the conductor 70 and the terminal 50 in the second clamping region 62.

[0108] Furthermore, according to this embodiment, the terminal 50 has at least two second clamping regions 62, with a first clamping region 61 positioned between two second clamping regions 61. As a result, the presence of a first clamping region 61 with a larger diameter between two second clamping regions 62 where the diameter of the conductor 70 becomes smaller generates a frictional force that resists tensile loads even in the first clamping region between them. This reduces the mean stress σ2 generated in the second clamping regions 62, thereby more reliably preventing fracture of the conductor portion 71 in the second clamping regions 62.

[0109] Furthermore, according to this embodiment, the terminal 50 is joined to the conductor portion 71 of the conductor 70 by resistance welding and crimping. In such cases, poor contact is likely to occur due to the difference in the amount of expansion and contraction between the terminal 50 and the conductor 70. However, this embodiment, by having the above-described features, reliably ensures a stable electrical connection between the conductor portion 71 of the conductor 70 and the terminal 50, and significantly prevents the conductor portion 71 of the conductor 70 from breaking and the conductor 70 from falling off the terminal 50.

[0110] Furthermore, according to this embodiment, the terminal 50 is made of copper or a copper alloy. In such cases, because the terminal 50 is made of copper or a copper alloy, it is more prone to shrinkage than the conductor 70 made of aluminum or an aluminum alloy, and it is difficult for the terminal 50 and the conductor 70 to adhere closely to each other after resistance welding. However, this embodiment, by having the above-described features, ensures electrical conductivity between the conductor portion 71 of the conductor 70 and the terminal 50, and significantly prevents the conductor portion 71 of the conductor 70 from breaking in the second clamping region 62 and the conductor 70 from falling off the terminal 50.

[0111] Furthermore, according to this embodiment, the clamping portion 60 has a folded portion 64 formed by folding back a part of the terminal 50, an opposing portion 65 facing the folded portion 64, and a curved portion 66 connecting the folded portion 64 and the opposing portion 65. The second clamping region 62 of the clamping portion 60 has a projection 63 formed on the folded portion 64 and a projection 63 formed on the opposing portion 65, with the projection 63 of the folded portion 64 and the projection 63 of the opposing portion 65 facing each other with the conductor 70 in between. This makes it easy to obtain a shape that secures the necessary amount of crushing for the second clamping region 62 by projections 63 that protrude so as to face each other.

[0112] Furthermore, if a space remains between the projection 63 of the folded portion 64, the projection 63 of the opposing portion 65, and the curved portion 66, the conductor 70 may fall into this space, making it impossible to obtain an appropriate amount of compression. In contrast, according to this embodiment, the projection 63 formed on the curved portion 66 is formed continuously with the projection 63 formed on the folded portion 64 and the projection 63 formed on the opposing portion 65, and bites into the conductor 70. As a result, since a projection 63 is also formed on the curved portion 66, an appropriate amount of compression can be ensured even for the conductor 70 that falls into the space between the projection 63 of the folded portion 64, the projection 63 of the opposing portion 65, and the curved portion 66. [Explanation of Symbols]

[0113] 10... Teeth Department 20… Stator core 30... Coil 50... Terminals 60...Holding part (hook-shaped part) 61...First clamping area 62...Second clamping area 63...Protrusion 64...Folded section 65... Opposite section 66... ​​Curved section 70...Conducting wire 71...Conductor part 100...Electric motor

Claims

1. In an electric motor comprising a stator core having multiple teeth, coils wound around the teeth, and terminals to which wires extending from the coils are connected, The aforementioned conductor is an aluminum wire whose conductor portion is made of aluminum or an aluminum alloy. The terminal is equipped with a clamping portion for clamping the conductor, The clamping portion has a first clamping region and a second clamping region, wherein the amount of crushing of the conductor portion of the conductor in the first clamping region and the amount of crushing of the conductor portion of the conductor in the second clamping region are different from each other. The first clamping region and the second clamping region are arranged side by side in the direction in which the conductor extends within the portion clamped by the clamping portion. Electric motor.

2. The electric motor according to claim 1, The first amount of crushing, which is the amount by which the conductor portion of the wire is crushed in the first clamping region, is smaller than the second amount of crushing, which is the amount by which the conductor portion of the wire is crushed in the second clamping region. Electric motor.

3. The electric motor according to claim 2, The second clamping region is a clamping region that stably connects the conductor portion of the conductor and the terminal, The first clamping region is a clamping region that prevents the conductor portion from breaking in the second clamping region. Electric motor.

4. The electric motor according to claim 3, The first compression amount is such that a frictional force is generated in the first clamping region that resists a predetermined tensile load in the longitudinal direction of the conductor, thereby reducing the magnitude of the frictional force generated in the second clamping region, and making the average stress in a cross section perpendicular to the longitudinal direction applied to the portion of the conductor clamped in the second clamping region less than the tensile strength of the material of the conductor. Electric motor.

5. The electric motor according to claim 4, When the predetermined tensile load is 7 [N], the average stress of the conductor in the second clamping region is less than the tensile strength of the material of the conductor. Electric motor.

6. The electric motor according to claim 2, The diameter d1 of the conductor portion of the wire in the short axis direction after being crushed by the first clamping region satisfies the following condition (1): Electric motor. d1≧0.21 [mm] (1)

7. The electric motor according to claim 2, The terminal is formed such that the first clamping region and the second clamping region are adjacent to each other in the direction in which the conductor extends. The length of the first clamping region in the direction in which the conductor extends is greater than the length of the second clamping region in the direction in which the conductor extends. Electric motor.

8. The electric motor according to claim 2, The terminal is formed such that the first clamping region and the second clamping region are adjacent to each other in the direction in which the conductor extends. The length of the first clamping region in the direction in which the conductor extends is greater than the wire diameter of the conductor portion of the conductor before it is crushed. Electric motor.

9. The electric motor according to claim 2, The second amount of compression is such that electrical conductivity between the conductor portion of the wire and the terminal is maintained even after a heat shock test is performed, which involves repeatedly subjecting the motor, to high and low temperature changes while the conductor portion and the terminal are joined together. Electric motor.

10. The electric motor according to claim 9, The second compression amount Δd2 satisfies the following condition (2), where d0 is the diameter of the conductor portion of the conductor before the conductor is compressed, and d2 is the diameter of the conductor portion in the short axis direction in the second clamping region after the conductor is compressed. Electric motor. Δd2=d0-d2≧0.15[mm] (2)

11. The electric motor according to claim 2, The wire diameter d0 of the conductor portion of the aforementioned conductor before it is crushed satisfies the following condition (3). Electric motor. 0.30≦d0≦0.40 [mm] (3)

12. The electric motor according to claim 1, The terminal is such that the first clamping region is positioned on both sides of the second clamping region in the direction in which the conductor extends. Electric motor.

13. The electric motor according to claim 12, The clamping portion of the terminal has at least two second clamping regions, and the first clamping region is positioned between the two second clamping regions in the direction in which the conductor extends. Electric motor.

14. The electric motor according to claim 1, The terminal is joined to the conductor portion of the wire by resistance welding and crimping. Electric motor.

15. The electric motor according to claim 14, The terminal is formed of copper or a copper alloy. Electric motor.

16. The electric motor according to claim 1, The clamping portion has a folded portion formed by folding back a part of the terminal, a facing portion opposite the folded portion, and a curved portion connecting the folded portion and the facing portion. In the second clamping region of the clamping portion, a projection is formed on the folded portion and a projection is formed on the opposing portion, and the projection on the folded portion and the projection on the opposing portion face each other with the conductor in between. Electric motor.

17. The electric motor according to claim 16, The projection formed on the curved portion is formed in continuity with the projection formed on the folded portion and the projection formed on the opposing portion, and is embedded in the conductor. Electric motor.

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