Double-tube housing structure for rotating electrical machines

Abstract

To suppress vibration and noise of an outer housing.SOLUTION: Double pipe housing structure of a drive motor 2 is constituted of an inner housing 23 and an outer housing 24 held by the drive motor 2. The inner housing 23 is fixed to the outer housing 24 by fitting on one end side and fixed to the outer housing 24 by bolt tightening on the other end side. A fitting part A between the inner housing 23 and the outer housing 24 is provided at a position not to overlap a bolt tightening part B of the inner housing 23 and the outer housing 24 when it is viewed along an axial direction. The fitting part A has: a projection part A1 provided in the inner housing 23 to project in a circumferential direction; and a groove part A2 provided in the outer housing 24 and into which the projection part A1 fits in the circumferential direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a double-tube housing structure for a rotating electrical machine. [Background technology]

[0002] Patent Document 1 discloses a rotating electric machine in which one end of an inner housing is fixed to an outer housing by press fitting (or shrink fitting), and the other end of the inner housing is fixed to the outer housing by fastening with bolts. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 213052 Summary of the Invention [Problem to be solved by the invention]

[0004] In a rotating electric machine, electromagnetic excitation force generates radial vibration in the stator, and therefore, when the inner housing is fitted radially into the outer housing, the radial vibration of the stator is transmitted to the outer housing via the inner housing, which may cause vibration and noise in the outer housing.

[0005] The present invention has been made in consideration of the above problems, and has an object to suppress vibration and noise from the outer housing. [Means for solving the problem]

[0006] In a double-tube housing structure for a rotating electric machine according to one embodiment of the present invention, the rotating electric machine has an inner housing and an outer housing. One end of the inner housing is fixed to the outer housing by fitting, and the other end is fixed to the outer housing by bolt fastening. The fitting portions of the inner housing and the outer housing are provided at positions that do not overlap with the circumferential positions of the bolt fastening portions of the inner housing and the outer housing when viewed along the axial direction. The fitting portion is a projection provided on one of the inner housing and the outer housing that protrudes in the circumferential direction, and a projection provided on the other of the inner housing and the outer housing that fits in the circumferential direction. At the same time, there is no radial fit. and a groove portion. Effect of the Invention

[0007] According to this aspect, the direction of vibration transmitted from the stator to the outer housing via the inner housing can be changed from the radial direction to the circumferential direction by the fitting portion. As a result, the effect of radial vibration on the outer housing is reduced, making it possible to reduce vibration and noise of the outer housing. In addition, since the fitting portion and the bolt fastening portion are offset from each other in the circumferential direction, the rigidity of the inner housing and the outer housing of the double tube structure is ensured in a well-balanced manner. As a result, this also makes it possible to reduce vibration and noise of the outer housing. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic diagram of a drive unit. [Diagram 2] 2 is a schematic diagram of the drive unit as viewed from the rear in the vehicle front-rear direction. FIG. [Diagram 3] FIG. 2 is a cross-sectional view showing a main part of a drive motor. [Figure 4] FIG. 4 is a view of the fitting portion as viewed in the axial direction. [Diagram 5] FIG. 11 is a diagram showing the movement of a drive shaft. [Figure 6] FIG. 2 is an explanatory diagram of an inverter arrangement. [Figure 7]FIG. [Figure 8] 5A and 5B are diagrams illustrating deformation modes of a drive motor. [Figure 9] FIG. 13 is a diagram showing vibration levels according to frequencies. [Figure 10] FIG. 4 is a Bode diagram showing the radial frequency characteristics of the drive motor. [Figure 11] FIG. 4 is a Bode diagram showing the circumferential frequency characteristics of the drive motor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0010] FIG. 1 is a schematic diagram of the drive unit 1. FIG. 2 is a schematic diagram of the drive unit 1 as viewed from the rear in the vehicle longitudinal direction. FIG. 3 is a cross-sectional view showing a main part of the drive motor 2. FIG. 4 is a view of the fitting portion A as viewed along the axial direction. FIG. 3 shows the outer peripheral part of the drive motor 2 in a cross section including the central axis. The drive unit 1 is mounted on a vehicle. As shown in FIGS. 1 and 2, the drive unit 1 has a drive motor 2, an inverter 3, and a reduction gear 4. The vehicle is, for example, a series hybrid vehicle that drives the drive motor 2 using electric power generated by a generator motor by the power of an internal combustion engine. The vehicle may be an electric vehicle. The drive motor 2 constitutes a drive source of the vehicle. The inverter 3 is disposed on the upper part of the drive motor 2. The drive motor 2 and the inverter 3 are integrally structured by bolt fastening, and the case of the inverter 3 is fixed to the case of the drive motor 2 by bolt fastening. The reduction gear 4 is connected to the drive motor 2, and the driving force of the drive motor 2 is input to the reduction gear 4. The drive motor 2 and the reduction gear 4 are integrally structured by bolt fastening. 2, the reducer 4 extends below the drive motor 2 and is connected to a drive shaft 5. The driving force of the drive motor 2 is transmitted to the drive shaft 5 via the reducer 4. The drive motor 2 corresponds to a rotating electric machine, and the reducer 4 corresponds to a gear box.

[0011] As shown in FIG. 3, the drive motor 2 has a rotor 21, a stator 22, an inner housing 23, and an outer housing 24. The rotor 21 is a rotor and is provided on the outer periphery of the rotating shaft of the drive motor 2. The stator 22 is a stator and is provided on the inner periphery of the inner housing 23. The inner housing 23 and the outer housing 24 both have a cylindrical shape, and the inner housing 23 is inserted into a first cylindrical portion 241 and a second cylindrical portion 242 of the outer housing 24. The first cylindrical portion 241 has an inner diameter slightly larger than the outer diameter of the inner housing 23. The second cylindrical portion 242 is connected to the first cylindrical portion 241 from one end side and has a smaller diameter than the first cylindrical portion 241. A ring-shaped cooling groove portion 231 is formed on the outer periphery of the inner housing 23. A plurality of cooling groove portions 231 are provided along the axial direction, and form a coolant flow path together with the first cylindrical portion 241. A first seal member 25 and a second seal member 26 are provided between the first cylindrical portion 241 and the inner housing 23 in a manner that sandwiches the entire cooling groove portions 231 therebetween in the axial direction. The first seal member 25 and the second seal member 26 close the radial clearance between the first cylindrical portion 241 and the inner housing 23. The first seal member 25 and the second seal member 26 may be an O-ring.

[0012] The inner housing 23 and the outer housing 24 have a fitting portion A on the right side in the left-right direction of the vehicle. The right side in the left-right direction of the vehicle is one end side. The one end side is the side to which the reducer 4 is connected, and constitutes the tip side when the inner housing 23 is inserted into the outer housing 24. The fitting portion A has a protrusion portion A1 and a groove portion A2. The protrusion portion A1 is provided on the inner housing 23, and the groove portion A2 is provided on the outer housing 24. The protrusion portion A1 is provided on one end of the inner housing 23. The groove portion A2 is provided on the one end side of the first cylindrical portion 241, and is provided at a position facing the protrusion portion A1 in a state in which the fitting portion A is fitted. The second cylindrical portion 242 is provided in a ring-shaped wall portion protruding radially inward, and the groove portion A2 is provided on the wall portion. The protrusion portion A1 is provided radially inward from the bottom surface of the groove portion A2. Therefore, when the inner housing 23 is inserted into the outer housing 24, the protrusions A1 can reach the grooves A2 without interfering with the outer housing 24. The fitting of the fitting parts A is performed by, for example, press fitting or shrink fitting. As a result, the inner housing 23 is fixed to the outer housing 24 by fitting at one end side. A plurality of fitting parts A are provided along the circumferential direction. The fitting parts A will be described in more detail below.

[0013] The inner housing 23 and the outer housing 24 further have a bolt fastening portion B on the other end side, that is, the left side in the vehicle left-right direction. As also shown by a dashed line in FIG. 3, the bolt fastening portion B is provided at a position where the circumferential position does not overlap the fitting portion A when viewed along the axial direction. The bolt fastening portion B is composed of a bolt insertion hole and a bolt fastening hole that correspond to each other. The bolt insertion hole is formed in a flange portion 232 that is provided at the other end of the inner housing 23 and protrudes radially outward. The bolt fastening hole is formed in an opening boss portion 243 that is provided on the other end side of the outer housing 24. The flange portion 232 abuts against the opening boss portion 243 in a state where the fitting portion A is fitted. The corresponding bolt insertion hole and the bolt fastening hole are provided at a position where they overlap each other in the axial direction in a state where the fitting portion A is fitted. A fastening bolt 27 is fastened to the bolt fastening hole through the corresponding bolt insertion hole. As a result, the inner housing 23 is fixed to the outer housing 24 by fastening the bolt at the other end side. A plurality of bolt fastening portions B are provided along the circumferential direction.

[0014] As shown in FIG. 4, the protrusion A1 protrudes in the circumferential direction. The protrusion A1 protrudes radially outward. The protrusion A1 protrudes along the radial direction. The groove A2 is concave in the circumferential direction. The groove A2 is concave radially outward. The groove A2 is concave along the radial direction. The protrusion A1 fits with the groove A2 in the circumferential direction, but does not fit with the groove A2 in the radial direction. Therefore, the direction of the vibration generated by the electromagnetic excitation force and transmitted from the stator 22 to the outer housing 24 via the inner housing 23 changes from the radial direction to the circumferential direction as shown diagrammatically by the arrow C. This reduces the effect of the radial vibration in the outer housing 24 as diagrammatically shown by the arrow R and the cross mark. As a result, the vibration and noise of the outer housing 24 are reduced. Both circumferential side surfaces of the protrusion A1 are formed of curved surfaces that are convex when viewed along the axial direction. Both circumferential side surfaces of the groove portion A2 are formed of flat surfaces that gradually move apart radially outward when viewed along the axial direction, i.e., flat surfaces that diverge toward the end. This reduces the fitting allowance of the fitting portion A that fits in the circumferential direction, improving the ease of assembly of the inner housing 23.

[0015] FIG. 5 is a diagram showing the movement of the drive shaft 5. As shown in FIG. 5, the drive shaft 5 is connected to the reducer 4 via the inner joint 6 and is connected to the drive wheels via the outer joint 7. The inner joint 6 and the outer joint 7 are, for example, ball joints. As shown by the dashed line in FIG. 5, the drive shaft 5 mainly moves up and down with the inner joint 6 as a fulcrum. For this reason, it is difficult to provide ribs or the like to the outer housing 24 located directly above the drive shaft 5 in order to provide rigidity. As a result, the rigidity of the outer housing 24 is lowest at the lower part. On the other hand, in the drive unit 1, the moment M2 on the lower side increases due to the structure in which the reducer 4 extends below the drive motor 2. Similarly, in the drive unit 1, the moment M1 on the upper side increases due to the structure in which the inverter 3 is disposed above the drive motor 2. For this reason, in this embodiment, the fitting portion A is disposed as follows.

[0016] FIG. 6 is an explanatory diagram of the arrangement of the inverter 3. FIG. 7 is an explanatory diagram of the arrangement of the fitting portion A. In FIG. 7, the bolt fastening portion B is circled with a thick line. As shown in FIG. 6, the inverter 3 is arranged on a boss portion BS provided on the upper portion of the drive motor 2. The boss portion BS includes a first boss portion BS1 provided at the front end portion in the vehicle longitudinal direction and a second boss portion BS2 provided at the rear end portion. The first boss portion BS1 includes a one-end boss portion BS11 provided at one end side and an other-end boss portion BS12 provided at the other end side. The second boss portion BS2 includes a one-end boss portion BS21 provided at one end side and an other-end boss portion BS22 provided at the other end side. Thus, the inverter 3 is fixed at the four corners to the upper portion of the drive motor 2. The boss portion BS may be provided extending in the vehicle longitudinal direction. That is, the drive motor 2 may be provided with a boss portion BS formed to connect the one-end boss portion BS11 and the one-end boss portion BS21, and a boss portion BS formed to connect the other-end boss portion BS12 and the other-end boss portion BS22. Furthermore, the boss portions BS thus formed may be connected to each other at their front and rear ends.

[0017] As shown in FIG. 7, the fitting portion A is provided at a first position P1, a second position P2, and a third position P3. The first position P1 is a position where the vehicle front-rear direction position overlaps with the first boss portion BS1 when viewed along the direction D, and is the upper position of two positions, upper and lower. The direction D is a direction perpendicular to the upper surface of the boss portion BS, and the forward and rearward arrows shown diagonally indicate the front-rear direction when viewed along the direction D. In this case, the two upper and lower positions are the first position P1 and the fourth position P4, and the upper position is, in other words, a position on the inverter 3 side. The position where the fitting portion A overlaps with the first boss portion BS1 may be a position where the fitting portion A overlaps with at least one of the one end side boss portion BS11 and the other end side boss portion BS12. The second position P2 is a position where the vehicle front-rear direction position overlaps with the second boss portion BS2 when viewed along the direction D, and is the upper position of two positions, upper and lower. The third position P3 is the position where the vehicle longitudinal position overlaps with the drive shaft 5 when viewed along the direction D, and is the lower of the two upper and lower positions. The position where the drive shaft 5 overlaps is the position where the drive shaft 5 extends along the vehicle lateral direction. The lower position is, in other words, the position on the drive shaft 5 side. As a result, the fitting portion A that fits in the circumferential direction is arranged in correspondence with the inverter 3 and the reducer 4 of the portion that protrudes in the vertical direction relative to the drive motor 2. Therefore, the rigidity of the drive motor 2 relative to the inverter 3 and the reducer 4 of the protruding portion, that is, the rigidity of the drive motor 2 relative to the whirling of the drive unit 1, is increased. As a result, the circumferential vibration shown by the arrows V1 and V2 in FIG. 7, that is, the torsional vibration, that is, the circumferential vibration, generated in the outer housing 24 due to the whirling of the drive unit 1, is suppressed.

[0018] FIG. 8 is an explanatory diagram of the deformation mode of the drive motor 2. As shown in FIG. 8, the inner housing 23 and the outer housing 24 of the drive motor 2 are deformed in a circular mode. When there is one fitting portion A, a circular primary mode deformation occurs. In this case, since there is only one fixed portion, deformation occurs in which the entire ring is displaced as shown by the broken line, and twisting is likely to occur. When there are two fitting portions A, a circular secondary mode deformation occurs. In the circular secondary mode, an elliptical deformation occurs as shown by the broken line. In this case, since there are not enough fixed portions, twisting is likely to occur. When there are four fitting portions A, a circular secondary deformation mode occurs in addition to a circular quartic deformation mode. Furthermore, when there are four or more fitting portions A, manufacturing may be difficult due to manufacturing constraints and the like. For this reason, in this embodiment, the fitting portions A are provided at the first position P1, the second position P2, and the third position P3. This makes it possible to suppress the occurrence of twisting by utilizing the circular tertiary deformation mode in which a triangular deformation occurs.

[0019] Fig. 9 is a diagram showing vibration levels according to frequency. The dashed line shows the comparative example. The comparative example shows the case where the inner housing 23 and the outer housing 24 are fitted together in the radial direction. In the comparative example, the fitting is performed in the radial direction, so radial vibration remains. In the present embodiment, although it is slightly higher than the comparative example, circumferential vibration can be suppressed, and radial vibration is less likely to be transmitted from the inner housing 23 to the outer housing 24, so that radial vibration can be suppressed more than in the comparative example.

[0020] FIG. 10 is a diagram showing the radial frequency characteristics of the drive motor 2 in a Bode diagram. FIG. 11 is a diagram showing the circumferential frequency characteristics of the drive motor 2 in a Bode diagram. As shown in FIG. 10, in the case of the radial direction, the gains of the inner housing 23 and the outer housing 24 are generally different from each other, except for some regions such as the low frequency region shown in a circle. In addition, the phase difference between the inner housing 23 and the outer housing 24 does not occur over the entire frequency range, but occurs partially. This is because, in this embodiment, the radial coupling state of the inner housing 23 and the outer housing 24 is not maintained, and radial vibration is difficult to transmit. As shown in FIG. 11, in the case of the circumferential direction, the increase in the phase difference is generally suppressed up to the frequency F1. This is because, in this embodiment, the fitting portion A is fitted in the circumferential direction, so that the circumferential coupling state of the inner housing 23 and the outer housing 24 is maintained up to the frequency F1. Therefore, the gains of the inner housing 23 and the outer housing 24 are generally equal up to the frequency F1. In this embodiment, even in a frequency range higher than the frequency F1, the gain deviation between the inner housing 23 and the outer housing 24 is suppressed. This is because the torsional vibration in the solid propagation region is also suppressed by the annular third deformation mode.

[0021] Next, the main effects of this embodiment will be described.

[0022] In this embodiment, the inner housing 23 and the outer housing 24 of the drive motor 2 form a double-tube housing structure of the drive motor 2. The inner housing 23 is fixed to the outer housing 24 by fitting at one end, and is fixed to the outer housing 24 by bolt fastening at the other end. A fitting portion A of the inner housing 23 and the outer housing 24 is provided at a position that does not overlap with a bolt fastening portion B of the inner housing 23 and the outer housing 24 in the circumferential direction when viewed along the axial direction. The fitting portion A has a protrusion A1 provided on the inner housing 23 and protruding in the circumferential direction, and a groove portion A2 provided on the outer housing 24 into which the protrusion A1 fits in the circumferential direction.

[0023] According to this configuration, the direction of vibration transmitted from the stator 22 to the outer housing 24 via the inner housing 23 can be changed from the radial direction to the circumferential direction by the fitting portion A. As a result, the action of radial vibration in the outer housing 24 is reduced, so that the vibration and noise of the outer housing 24 can be reduced. In addition, since the fitting portion A and the bolt fastening portion B are shifted from each other in the circumferential direction, the rigidity of the inner housing 23 and the outer housing 24 having a double tube structure is ensured in a well-balanced manner. Furthermore, in this case, it is possible to suppress the entire stator 22 from vibrating radially in a radial manner, that is, the repeated fluctuation in the diameter of the stator 22 causing vibration, and the transmission of such vibration to the outer housing 24 can also be reduced. As a result, this also makes it possible to reduce the vibration and noise of the outer housing 24.

[0024] In this embodiment, a reduction gear 4 is connected to the drive motor 2. The fitting portion A is provided on one end side to which the reduction gear 4 is connected. With this configuration, the fitting portion A, which is used in combination with the bolt fastening portion B, can be appropriately positioned in the inner housing 23 and the outer housing 24, making it possible to reduce vibration and noise of the outer housing 24.

[0025] In this embodiment, the drive motor 2 is mounted on a vehicle. An inverter 3 is disposed on a boss portion BS provided on an upper portion of the drive motor 2. The boss portion BS includes a first boss portion BS1 provided at a front end portion in the vehicle longitudinal direction and a second boss portion BS2 provided at a rear end portion. The reducer 4 extends downward from the drive motor 2 and is connected to a drive shaft 5. The fitting portion A is provided at a first position P1, which is an upper one of two upper and lower positions where the vehicle longitudinal direction position overlaps with the first boss portion BS1 when viewed along the direction D, a second position P2, which is an upper one of two upper and lower positions where the vehicle longitudinal direction position overlaps with the second boss portion BS2 when viewed along the direction D, and a third position P3, which is a lower one of two upper and lower positions where the vehicle longitudinal direction position overlaps with the drive shaft 5 when viewed along the direction D.

[0026] According to this configuration, the fitting portion A that fits in the circumferential direction is disposed in correspondence with the inverter 3 and the reducer 4 that protrude from the drive motor 2, so that the rigidity of the drive motor 2 against the whirling of the drive unit 1 can be increased. As a result, it is possible to suppress the circumferential vibration that occurs in the outer housing 24 due to the whirling of the drive unit 1. Furthermore, according to this configuration, the circumferential vibration can be further suppressed by utilizing a circular cubic deformation mode.

[0027] The fitting parts A may be provided in a plurality of prime numbers. In this case, the fitting parts A may be provided at least one at an upper position (for example, the first position P1 or the second position P2) among two positions in the upper and lower directions where the vehicle longitudinal direction position overlaps with the boss part BS when viewed along the direction D, and at a lower position, i.e., the third position P3 among two positions in the upper and lower directions where the vehicle longitudinal direction position overlaps with the drive shaft 5 when viewed along the direction D. The fitting parts A may be provided evenly or distributed in the circumferential direction, that is, in a well-balanced manner. In this case, too, the rigidity of the drive motor 2 against the whirling of the drive unit 1 can be increased, thereby suppressing the circumferential vibration generated in the outer housing 24 due to the whirling of the drive unit 1. In addition, by providing a plurality of fitting parts A evenly or distributed in the circumferential direction and a prime number, it is also possible to suppress the circumferential vibration by utilizing a circular third-order deformation mode.

[0028] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments.

[0029] For example, the protrusion A1 may be provided on the outer housing 24 and configured to protrude in the circumferential direction, i.e., to protrude radially inward. At the same time, the groove A2 may be provided on the inner housing 23 so that the protrusion A1 fits in the circumferential direction. In this case as well, by fitting the fitting portion A in the circumferential direction, it is possible to reduce vibration and noise of the outer housing 24. [Explanation of symbols]

[0030] 1 Drive unit 2 Drive motor (rotating electric machine) 23 Inner housing 24 Outer housing 3 Inverter 4. Gearbox 5 Drive shaft A Fitting part A1 protrusion A2 groove B Bolt fastening part BS boss part BS1 1st boss section BS2 2nd boss part P1 1st position P2 2nd position P3 3rd position

Claims

1. A double-tube housing structure for a rotating electric machine, comprising an inner housing and an outer housing, one end of the inner housing being fixed to the outer housing by fitting and the other end being fixed to the outer housing by bolt fastening, a fitting portion of the inner housing and a fitting portion of the outer housing are provided at a position that does not overlap with a bolt fastening portion of the inner housing and the outer housing in a circumferential direction when viewed in an axial direction, The fitting portion includes a protrusion portion provided on one of the inner housing and the outer housing and protruding in a circumferential direction, and a groove portion provided on the other of the inner housing and the outer housing, into which the protrusion portion fits in the circumferential direction but does not fit in the radial direction. A double-tube housing structure for a rotating electrical machine.

2. 2. The double-tube housing structure for a rotating electrical machine according to claim 1, A gear box is connected to the rotating electric machine, The fitting portion is provided on the one end side to which the gear box is connected. A double-tube housing structure for a rotating electrical machine.

3. 3. The double-tube housing structure for a rotating electrical machine according to claim 2, The rotating electric machine is mounted on a vehicle, an inverter is disposed on a boss portion provided on an upper portion of the rotating electric machine; The boss portion includes a first boss portion provided at a front end portion in the vehicle front-rear direction and a second boss portion provided at a rear end portion, The gear box extends below the rotating electric machine and is connected to a drive shaft. The fitting portion is a first position, which is an upper position of two upper and lower positions, where a vehicle front-rear direction position overlaps with the first boss portion when viewed along a direction perpendicular to an upper surface of the boss portion; a second position which is an upper one of two upper and lower positions where the vehicle front-rear direction position overlaps with the second boss portion when viewed along a direction perpendicular to an upper surface of the boss portion; and a third position, which is a lower position of the two upper and lower positions, and is a position where the vehicle front-rear direction position overlaps with the drive shaft when viewed along a direction perpendicular to an upper surface of the boss portion; Each of the following is provided: A double-tube housing structure for a rotating electrical machine.

4. 3. The double-tube housing structure for a rotating electrical machine according to claim 2, The rotating electric machine is mounted on a vehicle, an inverter is disposed on a boss portion provided on an upper portion of the rotating electric machine; The gear box extends below the rotating electric machine and is connected to a drive shaft. The fitting portion is provided in a plurality of prime numbers, a position in the vehicle front-rear direction where the boss portion overlaps the boss portion when viewed along a direction perpendicular to an upper surface of the boss portion, and an upper position out of two upper and lower positions; and a lower position of two upper and lower positions where the vehicle front-rear direction position overlaps with the drive shaft when viewed along a direction perpendicular to an upper surface of the boss portion; At least one is provided for each of A double-tube housing structure for a rotating electrical machine.

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