JP2023183103A - motor unit - Google Patents

Abstract

To reduce noise which is easily sensed by an occupant of a vehicle and a user of a device adopting a motor unit when the motor unit operates.SOLUTION: A motor unit is a motor unit in which a motor body is stored in a motor case, the motor body is provided with a stator having at least a stator fastening part to be fastened to a bottom plate part of the motor case, and the motor case includes a side wall part erected from the bottom plate part, and an extension part extending to an inner peripheral side of the motor case from a position separate from the bottom plate part of the side wall part to hold the stator with the bottom plate part. The number of parts holding the stator by the extension part and the bottom plate part is less than the number of parts fastening the stator to the bottom plate part by using the stator fastening part.SELECTED DRAWING: Figure 2

Description

The present invention relates to a motor unit.

2. Description of the Related Art A structure is known in which a motor body, which is one type of rotating machine including a rotor and a stator, is housed in a motor case, and the stator is fastened to the motor case with bolts (for example, see Patent Document 1). Such a structure may be employed as a power source for a vehicle or as a power source for various devices.

JP 2020-18068 Publication

By the way, when the stator is fastened with bolts in a conventionally known structure, the stator is cantilevered with respect to the motor case at one end in the axial direction, and this point is different from the structure disclosed in Patent Document 1. It is also common in However, when these conventional structures are adopted as power sources for vehicles and equipment, noise that is easily perceived by vehicle occupants and equipment users is generated due to stator torsional resonance when the motor body operates. This may occur.

Therefore, an object of the invention disclosed in this specification is to reduce the noise that is easily perceived by the occupant of the vehicle in which the motor unit is adopted and the user of the device when the motor unit is operated.

The motor unit disclosed herein is a motor unit in which a motor main body is housed in a motor case, and the motor main body includes a stator having a stator fastening portion fastened to at least a bottom plate portion of the motor case, The motor case includes a side wall part that stands up from the bottom plate part, and a side wall part that extends toward an inner peripheral side of the motor case from a position of the side wall part away from the bottom plate part, and the stator is disposed between the side wall part and the bottom plate part. an extending portion that sandwichly holds the stator, and the number of portions where the stator is held between the extending portion and the bottom plate portion is the number of portions where the stator is fastened to the bottom plate portion using the stator fastening portion. less than the number of

The invention disclosed in this specification can reduce the noise that is likely to be perceived by the occupant of the vehicle in which the motor unit is employed or the user of the device when the motor unit is operated.

FIG. 1 is a plan view of the motor unit of the first embodiment. FIG. 2 is a sectional view taken along the line X1-X1 in FIG. FIG. 3 is a graph showing a comparison of the frequency and vibration level when the motor unit of the first embodiment operates and when the motor unit of the comparative example operates. FIG. 4 is a sectional view corresponding to FIG. 2 of the motor unit of the second embodiment. FIG. 5 is a sectional view corresponding to FIG. 2 of a motor unit according to a third embodiment including a lid. FIG. 6 is a plan view corresponding to FIG. 1 of the motor unit of the fourth embodiment. FIG. 7 is a sectional view corresponding to FIG. 2 of the motor unit of the fourth embodiment.

Embodiments of the present invention will be described below with reference to the accompanying drawings. However, in the drawings, the dimensions, proportions, etc. of each part may not be shown to completely match the actual ones. Furthermore, some drawings may be drawn with details omitted. Furthermore, the scale of each element drawn between each figure may be different.

(First embodiment)
<Motor unit configuration>
First, a schematic configuration of the motor unit 1A will be described with reference to FIGS. 1 and 2. The motor unit 1A includes a motor body 2 and a motor case 10 that houses the motor body 2. The motor unit 1A of this embodiment is mounted on a vehicle (not shown) as a drive source for the vehicle. The motor unit 1A includes a lid that is attached to the motor case 10, but FIGS. 1 and 2 show a state in which the lid is removed. The motor unit 1A also includes a power line extending from the motor body 2, but this is omitted in FIGS. 1 and 2. Note that the motor unit 1A can also be used as a power source for various devices other than a vehicle.

[Motor body]
The motor body 2 includes a stator 3 . The stator 3 includes a stator core 4 formed into a cylindrical shape by laminating a plurality of electromagnetic steel sheets punched into a predetermined shape that is generally annular, and a coil 5 that forms three phases, a U phase, a V phase, and a W phase. It is formed by attaching. FIG. 2 shows coil ends 5a located at both ends of the motor body 2 in the axis AX direction.

The stator core 4 is provided with a plurality of stator fastening portions for fastening the stator 3 to the motor case 10, which protrude radially outward at a plurality of locations on its outer peripheral edge. In this embodiment, a first stator fastening section 4a, a second stator fastening section 4b, and a third stator fastening section 4c are provided. The first stator fastening part 4a is provided with a bolt hole 4a1, the second stator fastening part 4b is provided with a bolt hole 4b1, and the third stator fastening part 4c is provided with a bolt hole 4c1. Note that the number of stator fastening parts is not limited to this as long as it is plural, and can be changed as appropriate, for example, to four or five.

The motor main body 2 includes a rotor 6 provided to oppose the stator 3 in the radial direction. The rotor 6 is formed by attaching a rotating shaft member 8 to a rotor core 7 formed into a cylindrical shape by laminating a plurality of electromagnetic steel plates punched into a predetermined approximately annular shape. The motor main body 2 may be a so-called IPM (Interior Permanent Magnet) motor in which the rotor 6 is equipped with a permanent magnet, or may be a reluctance motor without a permanent magnet.

[Motor case]
Next, the motor case 10 will be explained. Referring to FIG. 2, the motor case 10 includes a bottom plate part 11 and a side wall part 12 that stands up from the bottom plate part 11. Referring to FIG. 1, the side wall portion 12 is formed in a cylindrical shape so as to surround the bottom plate portion 11 along the outer peripheral edge of the bottom plate portion 11. As shown in FIG. The motor main body 2 is housed within an area surrounded by the side wall portion 12. Further, the side wall portion 12 includes a lid attachment portion 13 projecting toward the outside thereof, and a fixing portion 14 for attaching the motor unit 1A to the vehicle side. In this embodiment, the lid mounting portion 13 and the fixing portion 14 are each provided at three locations, but these installation locations are not limited to this, and their positions and numbers may be changed as appropriate. be able to.

The motor case 10 includes an extension part 15 that extends from a position of the side wall part 12 away from the bottom plate part 11 toward the inner peripheral side of the motor case 10 . The extending portion 15 is provided continuously from an edge of the side wall portion 12 located on the opposite side to the side where the bottom plate portion 11 is located. As shown in FIG. 1, the extending portion 15 is provided so as to overlap the first stator fastening portion 4a provided in the motor body 2 housed in the motor case 10. The extension portion 15 is provided with a bolt hole 15a. Any method may be used to provide the extension portion 15. For example, when forming the portion that will become the side wall portion 12 from the material, the portion extending from the side wall portion may be bent or formed by welding.

[Connecting the motor body to the motor case]
Next, the fastening of the motor body 2 to the motor case 10 will be explained. The motor body 2 is housed in the motor case 10 such that the first stator fastening portion 4 a is located between the bottom plate portion 11 and the extension portion 15 . Then, the bolt 9 is inserted from the side of the bolt hole 15a provided in the extension portion 15, and its tip is passed through the bolt hole 4a1 provided in the first stator fastening portion 4a to reach the bottom plate portion 11. Then, the bolts 9 are tightened so that the extending portion 15 and the first stator fastening portion 4a are tightened together, and the first stator fastening portion 4a is held between the bottom plate portion 11 and the extending portion 15. As a result, the bottom plate portion 11 is in contact with one end of the motor body 2 in the axis AX direction, and the extension portion 15 is in contact with the other end.

The motor main body 2 includes a second stator fastening part 4b, and the bolt 9 inserted into the bolt hole 4b1 of the second stator fastening part 4b reaches the bottom plate part 11 and is tightened. The motor main body 2 includes a third stator fastening part 4c, and similarly to the second stator fastening part 4b, the bolt 9 inserted into the bolt hole 4c1 reaches the bottom plate part 11 and is tightened. That is, all of the plurality of stator fastening parts are fastened to the bottom plate part 11 of the motor case 10.

Thereby, the motor main body 2 is fastened to the motor case 10. In addition, in this embodiment, by providing one extending portion 15 and tightening it together with the first stator fastening portion 4a, the first stator fastening portion 4a is provided between the bottom plate portion 11 and the extending portion 15. Although the stator fastening portions are sandwiched, an extending portion may be provided with respect to another stator fastening portion, and the stator fastening portion may be sandwiched between the bottom plate portion 11 and the extending portion 15. In other words, at least one stator fastening portion sandwiched between the bottom plate portion 11 and the extension portion 15 only needs to exist.

In the present embodiment, the stator 3 is held between one part by the extension part 15 and the bottom plate part 11, whereas the stator 3 is held by the stator fastening parts 4a, 4b, and 4c. There are three parts that are fastened to the bottom plate part 11. That is, the number of parts where the stator 3 is held between the extension part 15 and the bottom plate part 11 is smaller than the number of parts where the stator 3 is fastened to the bottom plate part 11 using the stator fastening parts 4a, 4b, and 4c.

<Noise reduction effect>
Next, the noise reduction effect in the first embodiment will be explained with reference to FIG. 3. FIG. 3 shows the frequency and vibration level during operation of the motor unit 1A of the first embodiment obtained through simulation, together with the frequency and vibration level during operation of the motor unit of the comparative example obtained through simulation. ing. The motor unit of the comparative example does not include the extension part 15 in the first embodiment, and the first stator fastening part 4a is also fastened in the same manner as the second stator fastening part 4b and the third stator fastening part 4c. This is the aspect. In other words, the motor unit of the comparative example has a conventional structure in which one end in the axial direction is supported in a cantilever manner with respect to the motor case. Note that illustration of the motor unit of the comparative example is omitted.

Referring to FIG. 3, a noise target line is drawn. The noise target line is set as the upper limit of allowable noise when designing a vehicle equipped with the motor unit 1A. Therefore, the motor unit 1A is required to have a noise level below the noise target line when the motor unit 1A operates. Regarding noise, the vehicle is evaluated to be more comfortable for occupants the more the noise is not only lower than the noise target line, but also its peak value deviates from the noise target line. Referring to FIG. 3 based on this viewpoint, in the comparative example shown by the broken line in FIG. 3, peak values are observed near frequencies f1 and f2, and the peak values are values close to the noise target line. It shows. On the other hand, in the first embodiment shown in practice in FIG. 3, the values near the frequencies f1 and f2 are lower than the values in the comparative example, and the amount of deviation from the noise target line is also large. There is.

Further, in the first embodiment, the peak value is shifted to the vicinity of the frequency f3 on the high frequency side compared to the comparative example. This is because in the first embodiment, the first stator fastening section 4a is held between the bottom plate section 11 and the extension section 15, so the noise propagation path changes and the resonance frequency (stator torsional frequency) of the motor unit 1A changes. This is thought to be due to a shift in resonance (resonance). In this embodiment, by adopting the above-mentioned fastening mode, the rigidity in fastening between the motor body 2 and the motor case 10 is improved, and it is considered that the rigidity of the motor unit 1A as a whole is also improved. . The higher the rigidity of an object, the higher the resonance frequency of the object appears. Therefore, in the motor unit 1A of the present embodiment, it is thought that the peak value of noise shifted to the higher frequency side due to the improved rigidity.

The higher the frequency of noise, the less likely it is to be perceived by vehicle occupants. Therefore, the higher the frequency of the noise target line, the higher the allowable vibration level is set. In this embodiment, as a result of the peak value of noise shifting to the high frequency side, the amount of deviation from the noise target line becomes large. This makes it difficult for the occupants of the vehicle to perceive the noise and improves the comfort of the vehicle.

As described above, in the motor unit 1A of the first embodiment, the motor main body 2 is held between the bottom plate part 11 and the extension part 15, and the first stator fastener fastens the stator 3 provided in the motor main body 2 to the motor case 10. It has a section 4a. Therefore, it is possible to reduce noise that is easily perceived by the vehicle occupant when the motor unit 1A is operated. Note that when the motor unit 1A is employed in a device other than a vehicle, the motor unit 1A can reduce noise that is easily perceived by the user of the device.

(Second embodiment)
Next, with reference to FIG. 4, a motor unit 1B of a second embodiment will be described. The motor unit 1B of the second embodiment includes a motor case 20 in place of the motor case 10 in the motor unit 1A of the first embodiment. Like the motor case 10 of the first embodiment, the motor case 20 includes a bottom plate part 21, a side wall part 22, and a lid attachment part 23, but includes an extension part 15 extending from the side wall part 12 (see FIG. 2). ) is not provided. The motor case 20 of the second embodiment includes a fastening member attachment portion 25 instead of the extension portion 15 and a fastening member 26 to which the fastening member attachment portion 25 is attached, as shown in an enlarged view of the X2 section. That is, in the second embodiment, the combination of the fastening member attachment portion 25 and the fastening member 26 exhibits the same function as the extension portion 15 in the first embodiment. Note that since the motor body 2 itself is not different from the first embodiment, the same reference numerals will be used in the following description, and detailed description thereof will be omitted. Further, in FIG. 4 as well, the lid body is shown in a removed state.

The fastening member mounting portion 25 is provided continuously from near the edge of the side wall portion 22 on the opposite side to the side where the bottom plate portion 21 is located toward the inner side thereof. The fastening member attachment portion 25 includes a bolt hole 25a. The fastening member 26 is a plate-shaped member and includes a first bolt hole 26a and a second bolt hole 26b. The fastening member 26 is attached to the fastening member mounting portion 25 by inserting the bolt 27 into the first bolt hole 26a and the bolt hole 25a provided in the fastening member mounting portion 25 and tightening the nut 28. Thereby, the fastening member 26 is placed in the same state as the extension portion 15 in the first embodiment.

Then, the first stator fastening part 4a is arranged between the bottom plate part 21 and the fastening member 26, and the bolt 9 is inserted into the second bolt hole 26b and the bolt hole 4a1 provided in the first stator fastening part 4a and tightened. Thereby, the first stator fastening portion 4a can be held between the bottom plate portion 21 and the fastening member 26. Note that the second stator fastening portion 4b and the third stator fastening portion 4c are also fastened to the bottom plate portion 21 in the same manner as in the first embodiment.

In this way, in the second embodiment as well, the motor body 2 can be fastened to the motor case 20 to obtain the motor unit 1B, similarly to the first embodiment. The motor unit 1B can also obtain the same effects as the motor unit 1A of the first embodiment.

(Third embodiment)
Next, with reference to FIG. 5, a motor unit 1C of a third embodiment will be described. The motor unit 1C of the third embodiment includes a motor case 30 in place of the motor case 10 in the motor unit 1A of the first embodiment. Like the motor case 10 of the first embodiment, the motor case 30 includes a bottom plate part 31, a side wall part 32, and a lid attachment part 33, but includes an extension part 15 extending from the side wall part 12 (see FIG. 2). ) is not provided. Furthermore, the motor case 30 does not include the fastening member mounting portion 25 and the fastening member 26 (see FIG. 4) that the second embodiment had. Note that since the motor body 2 itself is not different from the first embodiment, the same reference numerals will be used in the following description, and detailed description thereof will be omitted.

Although the description of the lid was omitted in the first embodiment and the second embodiment, the lid 40 will be described here. The lid 40 includes a mounting portion 41 that is attached to the lid mounting portion 33 provided on the motor case 30 . The mounting part 41 is provided with a bolt hole 41a, and by inserting the bolt 34 into the bolt hole 41a and the bolt hole 33a provided in the lid mounting part 33 and tightening the nut 35, the lid 40 is installed. It is attached to the motor case 30. The lid body 40 is equipped with a bearing 42 that rotatably supports the rotating shaft member 8.

The lid body 40 includes a pressing portion 43 at a position corresponding to the first stator fastening portion 4a. The pressing portion 43 is located above the first stator fastening portion 4a with the lid 40 attached to the motor case 30. The pressing portion 43 is provided with a bolt hole 43a. The pressing part 43 is also in contact with the upper edge of the side wall part 32 and extends from the side wall part 32, so it corresponds to the extending part 15 (see FIG. 2) in the first embodiment and is not extended. It can perform the same function as the installation part 15.

By attaching the lid body 40 to the motor case 30, the first stator fastening portion 4a is located between the bottom plate portion 31 and the pressing portion 43. Then, by inserting the bolts 9 into the bolt holes 43a and the bolt holes 4a1 and tightening them, the first stator fastening portion 4a can be held between the bottom plate portion 31 and the pressing portion 43. Note that the second stator fastening portion 4b and the third stator fastening portion 4c are also fastened to the bottom plate portion 21 in the same manner as in the first embodiment.

In this way, in the third embodiment as well, the motor body 2 can be fastened to the motor case 30 to obtain the motor unit 1C, similarly to the first embodiment. The motor unit 1C can also obtain the same effects as the motor unit 1A of the first embodiment.

(Fourth embodiment)
Next, a motor unit 1D according to a fourth embodiment will be described with reference to FIGS. 6 and 7. The motor unit 1D of the fourth embodiment includes a motor case 50 in place of the motor case 10 in the motor unit 1A of the first embodiment. The motor case 50 includes an extension section 151 in place of the extension section 15 included in the motor case of the first embodiment. The position where the extension part 151 is provided is different from the position where the extension part 15 is provided. The extending portion 15 in the first embodiment was provided in accordance with the position of the first stator fastening portion 4a. In contrast, the extending portion 151 of the fourth embodiment is provided at a position that does not overlap with any stator fastening portion. Referring to FIG. 7, the extension portion 151 is fixed to the stator 3 with bolts 91. As shown in FIG. On the other hand, the first stator fastening part 4a, the second stator fastening part 4b, and the third stator fastening part 4c are fixed to the bottom plate part 11 with bolts 9. Note that the other configurations of the fourth embodiment are the same as those of the first embodiment, so the same reference numerals are used for common components, and detailed description thereof will be omitted.

In this way, in the fourth embodiment as well, the motor body 2 can be fastened to the motor case 50 to obtain the motor unit 1D, similarly to the first embodiment. The motor unit 1D can also obtain the same effects as the motor unit 1A of the first embodiment.

The above-mentioned embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications to these embodiments are within the scope of the present invention, and furthermore, it is within the scope of the present invention. It is obvious from the above description that various other embodiments are possible within the scope.

1A, 1B, 1C Motor unit 2 Motor body 3 Stator 4 Stator core 4a First stator fastening section 4b Second stator fastening section 4c Third stator fastening section 6 Rotor 7 Rotor core 8 Rotating shaft member 9 Bolts 10, 20, 30 Motor case 11 , 21, 31 Bottom plate part 12, 22, 23 Side wall part 13, 23, 33 Lid attachment part 14 Fixed part 15, 151 Extension part 25 Fastening member attachment part 26 Fastening member 40 Lid body 43 Pressing part

Claims (1)

A motor unit in which a motor body is housed in a motor case,
The motor body includes a stator having at least a stator fastening part fastened to a bottom plate part of the motor case,
The motor case includes a side wall part that stands up from the bottom plate part, and a side wall part that extends toward an inner peripheral side of the motor case from a position of the side wall part away from the bottom plate part, and the stator is disposed between the side wall part and the bottom plate part. an extension part that holds the
The number of parts where the stator is held between the extension part and the bottom plate part is smaller than the number of parts where the stator is fastened to the bottom plate part using the stator fastening part.
motor unit.

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