electric motor

Abstract

The electric motor (100) is an electric motor (100) having a first part (1) and a second part (2) formed separately from each other, and is also provided with a screw (3) that fastens the first part (1) and the second part (2), an elastic gasket (4) that is arranged around the screw (3) and seals between the first part (1) and the second part (2) in the axial direction of the screw (3) and is elastically deformable, and a metal part (5) that is arranged between the screw (3) and the elastic gasket (4) in the radial direction of the screw (3) and electrically connects the first part (1) and the second part (2).

Description

[Technical Field]

[0001] The present disclosure relates to an electric motor having two parts formed separately from one another. [Background technology]

[0002] Conventional electric motors are known in which the motor body, including the stator, rotor, and frame, and accessories such as a terminal box are manufactured separately, and then the two parts are finally fastened together with screws. In this type of motor, the screw tightening force alone is not enough to completely seal the gap between the two parts, resulting in a structure with low waterproof and dustproof properties. For this reason, the above-mentioned electric motor is not suitable for use outdoors or in environments where it may be exposed to water.

[0003] Therefore, as disclosed in Patent Document 1, it is common practice to insert an elastic packing between the two parts to seal the gap between the two parts and thereby improve waterproof and dustproof properties.

[0004] However, in a structure where an elastic packing is sandwiched between two parts, the only earth conduction path between the two parts is the screw. Reliable earth conduction is required for all electrical products, not just electric motors, to prevent electric shock to people in the event of a current leak, but an earth conduction path that relies on a screw reduces the reliability of the earth conduction. In particular, when an elastic packing, which is prone to deformation and deterioration over time, is sandwiched between two parts, the reliability of the earth conduction becomes even lower. For example, the US safety standard for electric motors, UL1004-1, does not generally recognize the use of a screw as an earth conduction path when there is an elastic body between two parts. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 62-188956 Summary of the Invention [Problem to be solved by the invention]

[0006] In the technology disclosed in Patent Document 1, a spacer ring is placed around the screw between two components. However, when the two components are fastened with the screw, the thickness of the spacer ring is thinner than the thickness of the elastic packing, and the spacer ring is not always in contact with the two components. In other words, the spacer ring disclosed in Patent Document 1 does not electrically connect the two components and does not serve as an earth conduction path. Therefore, even with the technology disclosed in Patent Document 1, the earth conduction path relies solely on the screw, resulting in low reliability of earth conduction. Therefore, there is a need for the development of a structure that can always ensure an earth conduction path other than the screw.

[0007] The present disclosure has been made in view of the above, and aims to provide an electric motor that can always ensure a ground conduction path other than by a screw while ensuring waterproofing and dustproofing between two parts. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the electric motor according to the present disclosure is an electric motor including a first part and a second part formed separately from each other, and includes a screw, an elastic packing, and a metal part. The screw fastens the first part and the second part. The elastic packing is disposed around the screw to seal between the first part and the second part in the axial direction of the screw and is elastically deformable. The metal part is disposed between the screw and the elastic packing in the radial direction of the screw, and electrically connects the first part and the second part. The tightening force when fastening the first part and the second part with the screw elastically deforms so as to compress the elastic packing, and the metal part comes into contact with the first part and the second part, and the first part and the second part are electrically connected via the metal part. The part of the first part facing the second part 1st surface The whole of teeth, are on the same plane, and Radially Along Stretch attitude The second part faces the first part. Second surface The whole of teeth, are on the same plane, and Radially Along Stretch attitude The elastic packing is the first part The first side of and the second part Second The first part is placed between the two faces. 1st of the surface and the second part Second are in contact with each other. [Effects of the Invention]

[0009] The electric motor according to the present disclosure has the advantage that it is possible to always ensure a ground conduction path other than by a screw while ensuring waterproof and dustproof properties between the two parts. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing a part of the electric motor according to the first embodiment, illustrating a state before a first component and a second component are fixed together with screws; [Figure 2] FIG. 1 is a cross-sectional view showing a part of the electric motor according to the first embodiment, illustrating a state after the first component and the second component are fixed with screws. [Figure 3] FIG. 10 is a cross-sectional view showing a part of the electric motor according to the second embodiment, illustrating a state after the first component and the second component are fixed with screws. [Figure 4] FIG. 10 is a cross-sectional view showing a part of the electric motor according to the third embodiment, illustrating a state before the first component and the second component are fixed together with screws. [Figure 5] FIG. 10 is a cross-sectional view showing a part of the electric motor according to the third embodiment, illustrating a state after the first component and the second component are fixed with screws. [Figure 6] FIG. 10 is a cross-sectional view showing a part of the electric motor according to the fourth embodiment, showing a state before the first component and the second component are fixed with screws. [Figure 7] FIG. 10 is a cross-sectional view showing a part of the electric motor according to the fourth embodiment, illustrating a state after the first component and the second component are fixed with screws. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an electric motor according to an embodiment will be described in detail with reference to the drawings.

[0012] Embodiment 1 FIG. 1 is a cross-sectional view showing a portion of an electric motor 100 according to the first embodiment, illustrating a state before a first component 1 and a second component 2 are fastened together with a screw 3. FIG. 2 is a cross-sectional view showing a portion of an electric motor 100 according to the first embodiment, illustrating a state after the first component 1 and the second component 2 are fastened together with the screw 3. As shown in FIGS. 1 and 2 , the electric motor 100 includes a first component 1 and a second component 2 that are formed separately from each other. The electric motor 100 also includes a screw 3, an elastic packing 4, and a metal component 5. Hereinafter, when describing the directions of the components of the electric motor 100, the direction parallel to the axis AX of the screw 3 is referred to as the axial direction, the direction perpendicular to the axis AX is referred to as the radial direction, and the direction of rotation about the axis AX is referred to as the circumferential direction.

[0013] The first component 1 is the electric motor body having a stator, rotor, frame 1a, etc. Figures 1 and subsequent figures show a portion of frame 1a that houses the stator and rotor. Frame 1a is a metal component. The second component 2 is an accessory component such as a terminal box 2a that is attached to the electric motor body. Figures 1 and subsequent figures show a portion of terminal box 2a. Terminal box 2a is a metal component. The first component 1 and second component 2 are arranged axially spaced apart from each other via elastic packing 4 and metal component 5. The first component 1 is formed with a first through-hole 1b through which a screw 3 is inserted. The second component 2 is formed with a second through-hole 2b through which the screw 3 is inserted. The first through-hole 1b and second through-hole 2b are arranged coaxially with axis AX of the screw 3.

[0014] The screw 3 is a metal member that fixes (fastens) the first component 1 and the second component 2 together. The shank 3b of the screw 3 is inserted through the second insertion hole 2b, the inner periphery of the metal component 5, and the first insertion hole 1b. The shank 3b of the screw 3 is threaded into a thread groove (not shown) formed on the inner periphery of the first insertion hole 1b. The first insertion hole 1b functions as a screw hole into which the screw 3 is threaded. The second insertion hole 2b does not function as a screw hole into which the screw 3 is threaded. As shown in FIG. 2 , when the first component 1 and the second component 2 are fixed with the screw 3, the head 3a of the screw 3 is in contact with the surface of the second component 2 that faces away from the first component 1.

[0015] The elastic packing 4 is disposed around the screw 3 to seal between the first part 1 and the second part 2 in the axial direction and is an elastically deformable member. As shown in FIG. 1, the elastic packing 4 serves to seal the gap between the first part 1 and the second part 2 by compressing it by a mm when the first part 1 and the second part 2 are fastened together with the screw 3. The elastic packing 4 has an annular shape extending in the circumferential direction. The elastic packing 4 is made of a material such as rubber.

[0016] As shown in FIG. 2 , the metal part 5 is a metal part that is disposed radially between the screw 3 and the elastic packing 4 and electrically connects the first part 1 and the second part 2. The metal part 5 is disposed axially between the first part 1 and the second part 2. In this embodiment, the metal part 5 is a spacer. The metal part 5 has an annular shape extending in the circumferential direction. In this embodiment, the metal part 5 is made of a soft metal such as aluminum or brass. In other words, the metal part 5 is made of a metal that can be plastically deformed by the tightening force of the screw 3. The metal part 5 is disposed radially outward of the shank 3b of the screw 3 and spaced apart from the shank 3b.

[0017] As shown in FIG. 1 , when the first component 1 and the second component 2 are not fastened together by the screw 3 (when no tightening force is applied to the screw 3), the elastic packing 4 is at its natural length, and the thickness T1 of the elastic packing 4 in the axial direction is greater than the thickness T2 of the metal component 5 in the axial direction. In this state, the metal component 5 is in contact with the first component 1 but not with the second component 2. As shown in FIG. 2 , when the screw 3 is tightened, the tightening force applied when fastening the first component 1 and the second component 2 with the screw 3 elastically deforms the elastic packing 4 so that it is compressed, and the metal component 5 also comes into contact with the second component 2. In other words, the metal component 5 comes into contact with the first component 1 and the second component 2. This establishes electrical continuity between the first component 1 and the second component 2 via the metal component 5.

[0018] When a metal part 5 made of a soft metal is used as in this embodiment, the tightening force applied when fastening the first part 1 and the second part 2 with the screw 3 causes the metal part 5 to plastically deform and compress. Specifically, as the screw 3 is tightened, the elastic gasket 4 first begins to elastically deform and compress. Then, when the elastic gasket 4 is compressed to the same thickness T2 as the metal part 5, the tightening force acts on the metal part 5, causing the metal part 5 to plastically deform and compress. When the metal part 5 plastically deforms to a certain extent, the contact area between the metal part 5 and the first part 1 and the second part 2 increases, and a larger tightening torque is applied to the screw 3. Eventually, the metal part 5 plastically deforms until the specified tightening torque is reached. At this time, the elastic gasket 4 and the metal part 5 are in a compressed state.

[0019] Next, the effects of the electric motor 100 according to the first embodiment will be described.

[0020] In this embodiment, as shown in FIGS. 1 and 2 , the electric motor 100 includes a screw 3 that fastens the first component 1 and the second component 2 together, and an elastic gasket 4 that is disposed around the screw 3 and seals the gap between the first component 1 and the second component 2 in the axial direction while being elastically deformable. This configuration seals the gap between the first component 1 and the second component 2, ensuring waterproof and dustproof protection between the two components. Also, in this embodiment, as shown in FIG. 2 , the electric motor 100 includes a metal component 5 that is disposed between the screw 3 and the elastic gasket 4 in the radial direction and provides electrical continuity between the first component 1 and the second component 2. This configuration allows the metal component 5, in addition to the screw 3, to function as the earth conduction path 6, thereby ensuring a constant earth conduction path 6 other than the screw 3. Therefore, in this embodiment, the earth conduction path 6 other than the screw 3 can be always ensured while ensuring waterproof and dustproof protection between the two components.

[0021] To ensure waterproof and dustproof properties between the two components while also ensuring a ground conduction path 6 other than through the screws 3, the elastic gasket 4 and the metal component 5 must be manufactured so that their thicknesses T1 and T2 are the same. However, because the elastic gasket 4 and the metal component 5 typically have their own tolerances, it is difficult to manufacture the two components so that their thicknesses T1 and T2 are the same while taking into account the tolerances of the two components. In other words, a dimensional error occurs between the thickness T1 of the elastic gasket 4 and the thickness T2 of the metal component 5 when no force, such as a tightening force, is applied. In this embodiment, as shown in FIG. 2 , the tightening force applied when the first component 1 and the second component 2 are fastened with the screws 3 causes the elastic gasket 4 to elastically deform and compress. Furthermore, as the elastic gasket 4 elastically deforms, the metal component 5 comes into contact with the first component 1 and the second component 2, establishing electrical continuity between the first component 1 and the second component 2 via the metal component 5. With this configuration, by elastically deforming the elastic packing 4 when fastening the first component 1 and the second component 2, it is possible to absorb any dimensional error between the elastic packing 4 and the metal component 5. In other words, when fastening the first component 1 and the second component 2, the thickness T1 of the elastic packing 4 and the thickness T2 of the metal component 5 can easily be made the same. As a result, even if a dimensional error occurs between the thickness T1 of the elastic packing 4 in its non-elastically deformed state and the thickness T2 of the metal component 5, it is possible to ensure waterproofness and dustproofness between the two components, while always ensuring the earth conduction path 6 by means other than the screw 3.

[0022] Here, the relationship between the tolerance range of the thickness T1 of the elastic packing 4 and the tolerance range of the thickness T2 of the metal part 5 will be described. Here, let the reference dimension of the thickness T1 of the elastic packing 4 when the tolerance is 0 (zero) be b, the reference dimension of the thickness T2 of the metal part 5 when the tolerance is 0 be c, and the shrinkage amount (compression amount) of the elastic packing 4 be a. Since the elastic packing 4 needs to shrink (compress) to the same thickness T2 as the metal part 5, the relationship between the thickness T1 of the elastic packing 4 and the thickness T2 of the metal part 5 is expressed as T 2 < T 1 ≤ T 2 + a. Next, when assuming the tolerance range of the thickness T1 of the elastic packing 4 as b - 0.2a ≤ T 1 ≤ b + 0.2a, calculate the tolerance range of the thickness T2 of the metal part 5. When T 1 = b + 0.2a, the tolerance range of the thickness T2 of the metal part 5 is T 2 < b + 0.2a ≤ T 2 + a, so it is expressed as b - 0.8a ≤ T 2 < b + 0.2a. On the other hand, when T 1 = b - 0.2a, the tolerance range of the thickness T2 of the metal part 5 is T 2 < b - 0.2a ≤ T 2 + a, so it is expressed as b - 1.2a ≤ T 2 < b - 0.2a. Therefore, the tolerance range of the thickness T2 of the metal part 5 in the case assumed as above is expressed as b - 0.8a ≤ T 2 < b - 0.2a. For example, when a = 2.0 mm and b = 5.0 mm, the tolerance range of the thickness T2 of the metal part 5 is expressed as 3.4 mm < T 2 ≤ 4.6 mm. The tolerance range of the thickness T1 of the elastic packing 4 is b - 0.2a ≤ T 1 ≤ b + 0.2a, and the tolerance range of the thickness T2 of the metal part 5 is b - 0.8a ≤ T 2 < b - 0.2a. Both tolerance ranges vary depending on the value of a. However, for the elastic packing 4 with a low elastic modulus such as rubber, the value of a can be made relatively large, and the tolerance ranges of the thickness T1 of the elastic packing 4 and the thickness T2 of the metal part 5 can be made larger respectively. For this reason, when fixing the first part 1 and the second part 2, the design of making the thickness T1 of the elastic packing 4 and the thickness T2 of the metal part 5 the same becomes relatively easy.

[0023] In the present embodiment, there is no need to perform a special design on the first part 1 and the second part 2 shown in FIGS. 1 and 2. It is only necessary to use the elastic packing 4 and the metal part 5 in combination, so the electric motor 100 can be designed simply and at low cost.

[0024] In this embodiment, simply by adding or removing the elastic gasket 4 and metal component 5 shown in FIGS. 1 and 2, it is possible to manufacture an electric motor 100 that ensures waterproof and dustproof protection between the two components and an electric motor that does not ensure waterproof and dustproof protection between the two components. In other words, the two types of electric motors can share components other than the elastic gasket 4 and metal component 5. An electric motor that does not ensure waterproof and dustproof protection between the two components refers to, for example, an electric motor used in a clean indoor environment, where waterproof and dustproof protection between the two components is not required. In such an electric motor, the elastic gasket 4 and metal component 5 are removed, and the first component 1 and the second component 2 are in direct contact with each other, so the earth conduction path 6 is always maintained.

[0025] In this embodiment, as shown in Fig. 2, metal part 5 serves as earth conduction path 6, so highly reliable and permanent earth conduction can be achieved even when elastic packing 4, which is prone to deformation and deterioration over time, is sandwiched between two parts. Furthermore, in this embodiment, not only elastic packing 4 but also metal part 5 receives the tightening force and comes into contact with first part 1 and second part 2, preventing loosening of screw 3. This not only achieves highly reliable and permanent earth conduction, but also further ensures waterproof and dustproof properties between the two parts.

[0026] In this embodiment, as shown in FIGS. 1 and 2 , the material of the metal component 5 is a plastically deformable metal. The metal component 5 undergoes plastic deformation, compressing, due to the tightening force applied when the first component 1 and the second component 2 are fastened with the screws 3. The plastic deformation of the metal component 5 ensures a wider tolerance range for the thickness T2 of the metal component 5. Furthermore, by elastically deforming the elastic gasket 4 and plastically deforming the metal component 5 when fastening the first component 1 and the second component 2, dimensional errors between the elastic gasket 4 and the metal component 5 can be more effectively absorbed. That is, when fastening the first component 1 and the second component 2, the thickness T1 of the elastic gasket 4 and the thickness T2 of the metal component 5 can be easily made the same. This ensures waterproofness and dustproofness between the two components, while always ensuring a ground conduction path 6 other than via the screws 3, even if a dimensional error occurs between the thickness T1 of the elastic gasket 4 when not elastically deformed and the thickness T2 of the metal component 5 when not plastically deformed.

[0027] Next, a modification of the first embodiment will be described.

[0028] In this embodiment, the material of the metal part 5 is a metal that can be plastically deformed by a tightening force, but it may also be a metal that cannot be plastically deformed by a tightening force. In this embodiment, the shank 3b of the screw 3 is threadedly engaged only with a thread groove formed on the inner circumferential surface of the first insertion hole 1b, but a thread groove may be formed on the inner circumferential surface of the second insertion hole 2b and the shank 3b of the screw 3 may be threadedly engaged with the thread groove.

[0029] Embodiment 2 Next, an electric motor 100A according to a second embodiment will be described with reference to Fig. 3. This embodiment differs from the first embodiment in that a metal part 5A having a protrusion 50 is used. In the second embodiment, parts that overlap with those in the first embodiment are given the same reference numerals and descriptions thereof will be omitted.

[0030] FIG. 3 is a cross-sectional view showing a portion of an electric motor 100A according to a second embodiment, illustrating a state after the first component 1 and the second component 2 are fixed together with screws 3. As shown in FIG. 3, in this embodiment, the metal component 5A is a spacer with protrusions 50. The metal component 5A has protrusions 50 formed thereon, protruding toward the first component 1 and the second component 2. One end of the metal component 5A in the axial direction has a plurality of protrusions 50 formed thereon, protruding toward the first component 1. The other end of the metal component 5A in the axial direction has a plurality of protrusions 50 formed thereon, protruding toward the second component 2. Hereinafter, when it is necessary to distinguish between the protrusions 50 formed at one end and the other end of the metal component 5A, they will be referred to as protrusions 50A and protrusions 50B, respectively.

[0031] Each protrusion 50 tapers axially away from the metal component 5A. The shape of each protrusion 50 is preferably a pointed shape with a pointed tip, as in this embodiment, but may be other shapes. The first component 1 has an insulating painted surface 1c over its entire surface. The second component 2 has an insulating painted surface 2c over its entire surface. Due to the tightening force applied when fastening the first component 1 and the second component 2 with the screw 3, the protrusion 50A penetrates the painted surface 1c of the first component 1 and comes into contact with the metal portion (base material) of the first component 1, and the protrusion 50B penetrates the painted surface 2c of the second component 2 and comes into contact with the metal portion of the second component 2.

[0032] Next, the effects of the electric motor 100A according to the second embodiment will be described.

[0033] In this embodiment, as shown in FIG. 3 , metal component 5A has protrusions 50A and 50B that protrude toward first component 1 and second component 2, respectively. When first component 1 and second component 2 are fastened with screw 3, the fastening force causes protrusion 50A to penetrate painted surface 1c of first component 1 and contact a metal portion of first component 1, and protrusion 50B to penetrate painted surface 2c of second component 2 and contact a metal portion of second component 2. This configuration ensures electrical continuity between metal component 5A and the metal portions of first component 1 and second component 2, even if the surfaces of first component 1 and second component 2 that contact metal component 5A have painted surfaces 1c and 2c, respectively. Furthermore, contact of protrusion 50 of metal component 5A with the metal portions of first component 1 and second component 2, respectively, establishes a more reliable ground conduction path 6.

[0034] Next, a modification of the second embodiment will be described.

[0035] In the present embodiment, the first component 1 and the second component 2 each have an insulating painted surface 1c, 2c, and the metal component 5A has a protrusion 50 formed thereon that protrudes toward the first component 1 and the second component 2, respectively. However, this is not limiting. At least one of the first component 1 and the second component 2 may have an insulating painted surface 1c, 2c, and the protrusion 50 may be formed thereon that protrudes toward at least the component having the painted surface 1c, 2c. In this case, the fastening force applied when the first component 1 and the second component 2 are fastened with the screw 3 causes the protrusion 50 to penetrate the painted surface 1c, 2c of at least one of the first component 1 and the second component 2 and come into contact with a metal portion of at least one of the first component 1 and the second component 2.

[0036] Embodiment 3 Next, an electric motor 100B according to a third embodiment will be described with reference to Figures 4 and 5. This embodiment differs from the first and second embodiments in that a metal part 5B having a spacer 51 and a washer 52 is used. In the third embodiment, parts that overlap with those in the first and second embodiments are denoted by the same reference numerals and will not be described again.

[0037] FIG. 4 is a cross-sectional view showing a portion of an electric motor 100B according to a third embodiment, illustrating a state before the first component 1 and the second component 2 are fixed together with a screw 3. FIG. 5 is a cross-sectional view showing a portion of an electric motor 100B according to the third embodiment, illustrating a state after the first component 1 and the second component 2 are fixed together with a screw 3. As shown in FIG. 4, a metal component 5B has a spacer 51 and a washer 52. The spacer 51 is a flange-type spacer including a base 51a and a flange 51b. The inner diameter of the second insertion hole 2b is larger than the outer diameter of the base 51a.

[0038] As shown in FIG. 5 , the base 51a is disposed radially between the screw 3, the elastic packing 4, the second component 2, and the washer 52. The base 51a is a cylindrical portion extending in the axial direction. The base 51a is inserted through the inner periphery of the elastic packing 4, the second insertion hole 2b, and the inner periphery of the washer 52. The flange 51b extends radially outward from one axial end of the base 51a (in this embodiment, the end of the base 51a facing the head 3a of the screw 3). The flange 51b is located axially opposite the elastic packing 4, with the second component 2 and the washer 52 interposed therebetween. The other axial end of the base 51a is in contact with the surface of the first component 1 facing the second component 2.

[0039] The washer 52 is a toothed washer. The washer 52 is disposed between the flange 51b and the second component 2 in the axial direction. The washer 52 has protrusions 52a formed thereon that protrude toward the second component 2. Specifically, one end of the washer 52 in the axial direction has a plurality of protrusions 52a formed thereon that protrude toward the second component 2. Each of the protrusions 52a tapers as it moves away from the washer 52 in the axial direction. The shape of each of the protrusions 52a is preferably a pointed shape with a sharp tip as in this embodiment, but may be other shapes.

[0040] Of the first component 1 and the second component 2, only the second component 2 has an insulating painted surface 2c over its entire surface. The first component 1 does not have an insulating painted surface 1c (see FIG. 3). As shown in FIG. 4, when the first component 1 and the second component 2 are not fastened together with the screw 3, the length L of the base portion 51a in the axial direction is shorter than the sum of the thickness T1 of the elastic packing 4, the thickness T3 of the second component 2 having the painted surface 2c, and the thickness T4 of the washer 52. The thickness T4 of the washer 52 includes the thickness of the protrusion 52a. When the first component 1 and the second component 2 are not fastened together with the screw 3, the elastic packing 4 is in its natural length, and the spacer 51 is separated from the first component 1 on one side in the axial direction. The protrusion 52a is in contact with the painted surface 2c of the second component 2. 5, the tightening force applied when fastening the first component 1 and the second component 2 with the screws 3 elastically deforms the elastic packing 4 so that the spacer 51 comes into contact with the first component 1, and the protrusion 52a penetrates the painted surface 2c of the second component 2 and comes into contact with the metal portion of the second component 2 that has the painted surface 2c. In other words, the metal component 5 comes into contact with the first component 1 and the second component 2. This establishes electrical continuity between the first component 1 and the second component 2 via the metal component 5.

[0041] Next, the effects of the electric motor 100B according to the third embodiment will be described.

[0042] In this embodiment, as shown in FIG. 5 , the metal part 5B includes a spacer 51 and a washer 52. The spacer 51 includes a base 51a and a flange 51b. The base 51a is disposed radially between the screw 3 and the elastic packing 4 and extends axially. The flange 51b extends radially outward from one end of the base 51a in the axial direction and is located on the opposite side of the elastic packing 4 in the axial direction, with the second part 2 having the painted surface 2c sandwiched between them. The washer 52 is disposed axially between the flange 51b and the second part 2 having the painted surface 2c. The washer 52 has a protrusion 52a that protrudes toward the second part 2 having the painted surface 2c. When the first component 1 and the second component 2 are not fastened together with the screw 3, the length L of the base 51a in the axial direction is shorter than the sum of the thickness T1 of the elastic packing 4, the thickness T3 of the second component 2 having the painted surface 2c, and the thickness T4 of the washer 52. The tightening force applied when fastening the first component 1 and the second component 2 with the screw 3 elastically deforms the elastic packing 4, compressing it. The protrusion 52a penetrates the painted surface 2c of the second component 2 and contacts the metal portion of the second component 2 having the painted surface 2c. With this configuration, even if the painted surface 2c of the second component 2 is located on the contact surface with the washer 52, the protrusion 52a penetrates the painted surface 2c, thereby establishing electrical continuity between the metal portion of the second component 2 and the metal component 5B. Furthermore, the contact of the protrusion 52a of the washer 52 with the metal portion of the second component 2 ensures a more reliable earth conduction path 6.

[0043] In this embodiment, by using spacer 51 with flange 51b, after sandwiching elastic packing 4 between first component 1 and second component 2, spacer 51 can be arranged on the inner periphery of elastic packing 4, second insertion hole 2b, and washer 52. This improves the workability when assembling spacer 51.

[0044] Next, a modification of the third embodiment will be described.

[0045] The configurations of the first component 1, the second component 2, the flange 51b, the washer 52, and the protrusion 52a are not limited to the example shown in the figure. Only one of the first component 1 and the second component 2 may have the insulating painted surface 1c, 2c. The flange 51b may be located axially opposite the elastic gasket 4, with either the first component 1 or the second component 2 having the painted surface 1c, 2c in between. The washer 52 may be located axially between the flange 51b and either the first component 1 or the second component 2 having the painted surface 1c, 2c. The washer 52 may have a protrusion 52a formed thereon that protrudes toward either the first component 1 or the second component 2 having the painted surface 1c, 2c. Furthermore, when the first component 1 and the second component 2 are not fixed together with the screws 3, the length L of the base 51a in the axial direction is shorter than the sum of the thickness T1 of the elastic packing 4, the thickness of either the first component 1 or the second component 2 that has the painted surfaces 1c, 2c, and the thickness T4 of the washer 52. Furthermore, the fastening force applied when the first component 1 and the second component 2 are fixed together with the screws 3 elastically deforms the elastic packing 4 so that the protrusion 52a penetrates the painted surfaces 1c, 2c of either the first component 1 or the second component 2 and comes into contact with the metal portion of either the first component 1 or the second component 2 that has the painted surfaces 1c, 2c.

[0046] Embodiment 4 Next, an electric motor 100C according to a fourth embodiment will be described with reference to Figures 6 and 7. This embodiment differs from the first to third embodiments in that a metal part 5C having a first spacer 53, a second spacer 54, a first washer 55, and a second washer 56 is used. In the fourth embodiment, parts that overlap with those in the first to third embodiments are denoted by the same reference numerals, and description thereof will be omitted.

[0047] FIG. 6 is a cross-sectional view showing a portion of an electric motor 100C according to a fourth embodiment, illustrating a state before a first component 1 and a second component 2 are fixed together with a screw 3. FIG. 7 is a cross-sectional view showing a portion of an electric motor 100C according to the fourth embodiment, illustrating a state after the first component 1 and the second component 2 are fixed together with a screw 3. As shown in FIG. 6, a metal component 5C has a first spacer 53, a second spacer 54, a first washer 55, and a second washer 56. As shown in FIG. 7, the first spacer 53 and the second spacer 54 are overlapped in the axial direction.

[0048] The first spacer 53 is a flange-type spacer including a first base 53a and a first flange 53b. The inner diameter of the second insertion hole 2b is larger than the outer diameter of the first base 53a. The first base 53a is disposed radially between the screw 3, the elastic packing 4, the second component 2, and the first washer 55. The first base 53a is a cylindrical portion extending axially. The first base 53a is inserted through the inner periphery of the elastic packing 4, the second insertion hole 2b, and the inner periphery of the first washer 55. The first flange 53b extends radially outward from one end of the first base 53a in the axial direction (in this embodiment, the end of the first base 53a facing the head 3a of the screw 3). The first flange 53b is located on the opposite side of the elastic packing 4 in the axial direction, with the second component 2 and the first washer 55 interposed therebetween.

[0049] The second spacer 54 is a flange-type spacer including a second base 54a and a second flange 54b. The inner diameter of the first insertion hole 1b is larger than the outer diameter of the second base 54a. The inner diameter of the first insertion hole 1b is the same as the inner diameter of the second insertion hole 2b. The outer diameter of the first base 53a is the same as the outer diameter of the second base 54a. The second base 54a is radially disposed between the screw 3, the elastic packing 4, the first component 1, and the second washer 56. The second base 54a is a cylindrical portion extending in the axial direction. The second base 54a is inserted through the inner periphery of the elastic packing 4, the first insertion hole 1b, and the inner periphery of the second washer 56. One axial end of the second base portion 54a contacts the other axial end of the first base portion 53a. The second flange 54b extends radially outward from the other axial end of the second base portion 54a (in this embodiment, the end of the second base portion 54a facing away from the head 3a of the screw 3). The second flange 54b is located on the opposite side of the elastic packing 4 in the axial direction, with the first component 1 and the second washer 56 therebetween.

[0050] The first washer 55 is a toothed washer. The first washer 55 is disposed between the first flange 53b and the second component 2 in the axial direction. The first washer 55 has first protrusions 55a formed thereon, which protrude toward the second component 2. Specifically, one end of the first washer 55 in the axial direction has a plurality of first protrusions 55a formed thereon, which protrude toward the second component 2. Each of the first protrusions 55a tapers as it moves away from the first washer 55 in the axial direction. The shape of each of the first protrusions 55a is preferably a pointed shape with a pointed tip as in this embodiment, but may have other shapes.

[0051] The second washer 56 is a toothed washer. The second washer 56 is disposed between the second flange 54b and the first component 1 in the axial direction. The second washer 56 is formed with second protrusions 56a that protrude toward the first component 1. Specifically, one end of the second washer 56 in the axial direction is formed with a plurality of second protrusions 56a that protrude toward the first component 1. Each second protrusion 56a tapers as it moves away from the second washer 56 along the axial direction. The shape of each second protrusion 56a is preferably a pointed shape with a pointed tip as in the present embodiment, but may be other shapes.

[0052] The first component 1 has an insulating painted surface 1c over its entire surface. The second component 2 has an insulating painted surface 2c over its entire surface. As shown in FIG. 6 , when the first component 1 and the second component 2 are not fastened together with the screws 3, the sum of the length L1 of the first base portion 53a and the length L2 of the second base portion 54a in the axial direction is shorter than the sum of the thickness T1 of the elastic packing 4, the thickness T3a of the first component 1, the thickness T3b of the second component 2, the thickness T4a of the first washer 55, and the thickness T4b of the second washer 56. The thickness T4a of the first washer 55 includes the thickness of the first protrusion 55a. The thickness T4b of the second washer 56 includes the thickness of the second protrusion 56a. When the first component 1 and the second component 2 are not fastened together with the screws 3, the elastic gasket 4 is at its natural length, and the first spacer 53 and the second spacer 54 are spaced apart in the axial direction. The first protrusion 55a contacts the painted surface 2c of the second component 2. The second protrusion 56a contacts the painted surface 1c of the first component 1. As shown in FIG. 7 , the tightening force applied when fastening the first component 1 and the second component 2 with the screws 3 elastically deforms the elastic gasket 4, compressing it, and the first spacer 53 and the second spacer 54 come into contact with each other. The second protrusion 56a penetrates the painted surface 1c of the first component 1 and contacts the metal portion of the first component 1, and the first protrusion 55a penetrates the painted surface 2c of the second component 2 and contacts the metal portion of the second component 2. In other words, the metal component 5 comes into contact with the first component 1 and the second component 2. As a result, the first component 1 and the second component 2 are electrically connected via the metal component 5 .

[0053] Neither the first insertion hole 1b nor the second insertion hole 2b functions as a screw hole into which the screw 3 is threaded. For this reason, in this embodiment, the tip of the shank 3b of the screw 3 is threadedly engaged with the nut 7. The nut 7 is in contact with the end of the second flange 54b that faces away from the head 3a of the screw 3. Between the head 3a of the screw 3 and the nut 7, the first spacer 53, the second spacer 54, the first washer 55, the second washer 56, the second part 2, the elastic packing 4, and the first part 1 are sandwiched.

[0054] Next, the effects of the electric motor 100C according to the fourth embodiment will be described.

[0055] In this embodiment, as shown in FIG. 7 , the first component 1 and the second component 2 each have an insulating painted surface 1c, 2c. The metal component 5C includes a first spacer 53, a second spacer 54, a first washer 55, and a second washer 56. The first spacer 53 includes a first base 53a and a first flange 53b. The first base 53a is disposed radially between the screw 3 and the elastic packing 4 and extends axially. The first flange 53b extends radially outward from one end of the first base 53a in the axial direction and is located axially opposite the elastic packing 4, with the second component 2 interposed therebetween. The second spacer 54 includes a second base 54a and a second flange 54b. The second base 54a is disposed radially between the screw 3 and the elastic packing 4 and extends axially. One axial end of the second base portion 54a contacts the other axial end of the first base portion 53a. The second flange 54b extends radially outward from the other axial end of the second base portion 54a and is located on the opposite side of the elastic packing 4 with the first component 1 therebetween. The first washer 55 is disposed axially between the first flange 53b and the second component 2. The first washer 55 has a first protrusion 55a that protrudes toward the second component 2. The second washer 56 is disposed axially between the second flange 54b and the first component 1. The second washer 56 has a second protrusion 56a that protrudes toward the first component 1. 6, when the first component 1 and the second component 2 are not fastened together with the screws 3, the sum of the length L1 of the first base portion 53a and the length L2 of the second base portion 54a in the axial direction is shorter than the sum of the thickness T1 of the elastic gasket 4, the thickness T3a of the first component 1, the thickness T3b of the second component 2, the thickness T4a of the first washer 55, and the thickness T4b of the second washer 56. Furthermore, as shown in FIG. 7, the fastening force applied when the first component 1 and the second component 2 are fastened together with the screws 3 elastically deforms the elastic gasket 4 so that the second protrusion 56a penetrates the painted surface 1c of the first component 1 and comes into contact with a metal portion of the first component 1, and the first protrusion 55a penetrates the painted surface 2c of the second component 2 and comes into contact with a metal portion of the second component 2.With these configurations, even if painted surfaces 1c and 2c are present on the contact surface of first component 1 that contacts second washer 56 and the contact surface of second component 2 that contacts first washer 55, electrical conduction can be established between metal component 5C and the metal portions of first component 1 and second component 2. Furthermore, second protrusion 56a of second washer 56 contacts the metal portion of first component 1, and first protrusion 55a of first washer 55 contacts the metal portion of second component 2, thereby establishing a more reliable earth conduction path 6.

[0056] In this embodiment, by using second spacer 54 with second flange 54b, after sandwiching elastic packing 4 between first component 1 and second component 2, second spacer 54 can be disposed around the inner periphery of elastic packing 4, first insertion hole 1b, and second washer 56. Furthermore, by using first spacer 53 with first flange 53b, after sandwiching elastic packing 4 between first component 1 and second component 2, first spacer 53 can be disposed around the inner periphery of elastic packing 4, second insertion hole 2b, and first washer 55. This improves the workability when assembling first spacer 53 and second spacer 54.

[0057] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention. [Explanation of symbols]

[0058] 1 first part, 1a frame, 1b first insertion hole, 1c, 2c painted surface, 2 second part, 2a terminal box, 2b second insertion hole, 3 screw, 3a head, 3b shaft, 4 elastic packing, 5, 5A, 5B, 5C metal part, 6 earth conduction path, 7 nut, 50, 50A, 50B, 52a protrusion, 51 spacer, 51a base, 51b flange, 52 washer, 53 first spacer, 53a first base, 53b first flange, 54 second spacer, 54a second base, 54b second flange, 55 first washer, 55a first protrusion, 56 second washer, 56a second protrusion, 100, 100A, 100B, 100C electric motor.

Claims

1. An electric motor comprising a first component and a second component formed separately from each other, a screw for fixing the first component and the second component together; an elastic packing that is disposed around the screw to seal between the first component and the second component in the axial direction of the screw and is elastically deformable; a metal part disposed between the screw and the elastic packing in the radial direction of the screw, and electrically connecting the first part and the second part; Equipped with a fastening force applied when the first component and the second component are fixed together with the screw causes the elastic packing to be elastically deformed so as to be compressed, and the metal component comes into contact with the first component and the second component, and the first component and the second component are electrically connected via the metal component; a first surface of the first component facing the second component is entirely coplanar and extends along the radial direction; a second surface of the second component facing the first component is entirely coplanar and extends along the radial direction; the elastic packing is disposed between the first surface of the first component and the second surface of the second component, and is in contact with the first surface of the first component and the second surface of the second component, respectively.

2. An electric motor comprising a first component and a second component formed separately from each other, a screw for fixing the first component and the second component together; an elastic packing that is disposed around the screw to seal between the first component and the second component in the axial direction of the screw and is elastically deformable; a metal part disposed between the screw and the elastic packing in the radial direction of the screw, and electrically connecting the first part and the second part; Equipped with a fastening force applied when the first component and the second component are fixed together with the screw causes the elastic packing to be elastically deformed so as to be compressed, and the metal component comes into contact with the first component and the second component, and the first component and the second component are electrically connected via the metal component; a surface of the first component facing the second component is a plane extending in the radial direction; a surface of the second component facing the first component is a plane extending in the radial direction; the elastic packing is disposed between the flat surfaces of the first component and the second component; the metal part is disposed between the first part and the second part in the axial direction; At least one of the first component and the second component has an insulating painted surface; a protrusion is formed on the metal part, protruding toward at least one of the first part and the second part that has the painted surface; an electric motor characterized in that, due to the tightening force when the first component and the second component are fixed with the screw, the protrusion penetrates the painted surface and comes into contact with a metal portion of at least one of the first component and the second component that has the painted surface.

3. An electric motor comprising a first component and a second component formed separately from each other, a screw for fixing the first component and the second component together; an elastic packing that is disposed around the screw to seal between the first component and the second component in the axial direction of the screw and is elastically deformable; a metal part disposed between the screw and the elastic packing in the radial direction of the screw, and electrically connecting the first part and the second part; Equipped with a fastening force applied when the first component and the second component are fixed together with the screw causes the elastic packing to be elastically deformed so as to be compressed, and the metal component comes into contact with the first component and the second component, and the first component and the second component are electrically connected via the metal component; a surface of the first component facing the second component is a plane extending in the radial direction; a surface of the second component facing the first component is a plane extending in the radial direction; the elastic packing is disposed between the flat surfaces of the first component and the second component; Only one of the first component and the second component has an insulating painted surface, The metal part is a spacer including: a base portion disposed between the screw and the elastic packing in the radial direction and extending in the axial direction; and a flange extending radially outward from one end of the base portion in the axial direction and positioned on the opposite side of the elastic packing in the axial direction, with either the first component or the second component having the painted surface therebetween; a washer disposed in the axial direction between the flange and one of the first part and the second part, which has the painted surface; and a protrusion is formed on the washer, protruding toward either the first component or the second component, whichever has the painted surface; when the first part and the second part are not fixed together by the screw, the length of the base part in the axial direction is shorter than the sum of the thickness of the elastic packing, the thickness of either one of the first part and the second part that has the painted surface, and the thickness of the washer; an electric motor characterized in that the elastic gasket is elastically deformed so as to be compressed by the tightening force when the first component and the second component are fixed with the screw, and the protrusion penetrates the painted surface and comes into contact with a metal portion of either the first component or the second component that has the painted surface.

4. An electric motor comprising a first component and a second component formed separately from each other, a screw for fixing the first component and the second component together; an elastic packing that is disposed around the screw to seal between the first component and the second component in the axial direction of the screw and is elastically deformable; a metal part disposed between the screw and the elastic packing in the radial direction of the screw, and electrically connecting the first part and the second part; Equipped with a fastening force applied when the first component and the second component are fixed together with the screw causes the elastic packing to be elastically deformed so as to be compressed, and the metal component comes into contact with the first component and the second component, and the first component and the second component are electrically connected via the metal component; a surface of the first component facing the second component is a plane extending in the radial direction; a surface of the second component facing the first component is a plane extending in the radial direction; the elastic packing is disposed between the flat surfaces of the first component and the second component; each of the first component and the second component has an insulating painted surface; The metal part is a first spacer including: a first base portion disposed between the screw and the elastic packing in the radial direction and extending in the axial direction; and a first flange extending radially outward from one end of the first base portion in the axial direction and positioned on the opposite side of the elastic packing in the axial direction with either the first part or the second part therebetween; a first washer disposed between the first flange and one of the first part and the second part in the axial direction; a second spacer including: a second base portion disposed between the screw and the elastic packing in the radial direction, extending in the axial direction, with one end portion in the axial direction contacting the other end portion of the first base portion in the axial direction; and a second flange extending radially outward from the other end portion of the second base portion in the axial direction, and positioned on the opposite side of the elastic packing in the axial direction with the other of the first part and the second part therebetween; a second washer disposed between the second flange and the other of the first part and the second part in the axial direction; and a first protrusion is formed on the first washer, the first protrusion protruding toward either the first component or the second component; a second protrusion is formed on the second washer, the second protrusion protruding toward the other of the first component and the second component; when the first part and the second part are not fixed together with the screw, the sum of the length of the first base part and the length of the second base part in the axial direction is shorter than the sum of the thickness of the elastic packing, the thickness of the first part, the thickness of the second part, the thickness of the first washer, and the thickness of the second washer; an electric motor characterized in that the elastic packing is elastically deformed so as to be compressed by the tightening force when the first component and the second component are fixed with the screw, and the first protrusion penetrates the painted surface and contacts a metal portion of either the first component or the second component, and the second protrusion penetrates the painted surface and contacts a metal portion of the other of the first component and the second component.

5. the metal part is disposed between the first part and the second part in the axial direction; 3. The electric motor according to claim 1, wherein when the first component and the second component are not fixed together with the screw, the thickness of the elastic gasket in the axial direction is greater than the thickness of the metal component in the axial direction.

6. the material of the metal part is a plastically deformable metal, 6. The electric motor according to claim 5, wherein the metal part is plastically deformed in a compressive manner by the tightening force.

Images