Rotating electrical machine with a shrink-fit bearing
阅读说明:本技术 带有热配合轴承的旋转电机 (Rotating electrical machine with a shrink-fit bearing ) 是由 M.费克斯 Y.勒-梅图尔 E.西蒙 M.邦尼西 X.达尼斯梅 M.雷东 于 2018-04-26 设计创作,主要内容包括:本发明主要涉及一种用于机动车辆的旋转电机。电机(10)包括轴(13);转子(12);定子(16),其包括设有槽的主体(25)和插入槽中的绕组(26);第一轴承(37)和第二轴承(38),其围绕由转子和定子形成的组件并且各自包括用于可旋转地安装转子轴(13)的壳体(40、44)。第一轴承包括横向凸缘(371)和从所述凸缘的外周衍生的轴向定向的圆柱形壁(372)。第二轴承包括封闭第一轴承的横向凸缘(48)和从凸缘突出并形成接合区域(64)的至少一个边缘(63),在该接合区域中它与第一轴承接合。此外,定子主体具有热配合到圆柱形壁的区域(Z1)。(The present invention generally relates to a rotating electric machine for a motor vehicle. The motor (10) comprises a shaft (13); a rotor (12); a stator (16) comprising a body (25) provided with slots and windings (26) inserted in the slots; a first bearing (37) and a second bearing (38) surrounding the assembly formed by the rotor and the stator and each comprising a housing (40, 44) for rotatably mounting the rotor shaft (13). The first bearing includes a transverse flange (371) and an axially-oriented cylindrical wall (372) that derives from an outer periphery of the flange. The second bearing comprises a transverse flange (48) enclosing the first bearing and at least one edge (63) projecting from the flange and forming an engagement region (64) in which it engages the first bearing. Furthermore, the stator body has a zone (Z1) that is thermally fitted to the cylindrical wall.)
1. A rotating electric machine for motor vehicles, the electric machine (10) comprising:
-a shaft (13) extending along an axis (X);
-a rotor (12) fitted on a shaft (13);
-a stator (16) surrounding the rotor (12) in the presence of an air gap, said stator comprising a notched body (25) and a winding (26) inserted in the notch;
-a first bearing (37) and a second bearing (38) surrounding the assembly formed by the rotor and the stator,
it is characterized in that the preparation method is characterized in that,
-said first bearing (37) comprises a transverse flange (371) and a cylindrical wall (372) with axial orientation obtained from the outer periphery of said flange (371);
-said second bearing (38) comprises a transverse flange (48) closing the first bearing (37), and at least one edge (63) extending projecting from the flange (48) and forming a joint zone (64) with the first bearing; and is
-said stator body (25) comprises a thermal fitting zone (Z1) with the cylindrical wall (371).
2. A rotating electric machine according to claim 1, characterized in that the ratio of the axial height of the shrink fit region of the first bearing to the axial height of the stator body is 0.9 to 1.2, preferably 1.
3. A rotating electric machine according to claim 1 or 2, characterized in that the difference in diameter between the outer diameter (D2) of the stator body (27) and the inner diameter (D1) of the cylindrical wall (372) at the shrink-fit region (Z1) is between 0 and 0.7 mm.
4. The rotating machine according to any of claims 1-3, characterized in that the second bearing (38) comprises a plurality of edges (63) forming a plurality of engagement areas (64) with the first bearing, and in that the machine (10) comprises a plurality of openings (60) arranged between two consecutive engagement areas (64).
5. A rotating electric machine according to claim 4, characterized in that one of the bearings (37, 38) comprises a pin (61, 61'), which pin (61, 61') extends axially protruding towards the other bearing so as to at least partially obstruct the opening (60).
6. A rotating electric machine according to claim 4 or 5, characterized in that the cylindrical wall (372) comprises at least one notch (59) provided in an axially open manner in the free end of the wall axially opposite the flange (371), the notch being located facing the opening (60).
7. The rotating machine according to any of claims 1 to 6, characterized in that the cylindrical wall (372) of the first bearing (37) and the edge (63) of the second bearing (38) each comprise at least one centering portion (62, 78) and at least one fixed portion (71, 74), and in that the centering portion of the first bearing cooperates with the centering portion of the second bearing and in that the fixed portion of the first bearing cooperates with the fixed portion of the second bearing, said centering and fixed portions forming at least one engagement zone (64).
8. A rotating electric machine according to claim 7, characterized in that the rotating electric machine comprises a plurality of centering portions (62, 78) and a plurality of fixing portions (71, 74), and that for each bearing, each centering portion (62, 78) is arranged to face at least one fixing portion (71, 74).
9. A rotating machine according to claim 7 or 8, characterized in that the adjustment between the centering portion (62) of the first bearing (37) and the centering portion (78) of the second bearing (38) is defined according to an ISO adjustment system such that the inner diameter (D3) of the centering portion (62) of the first bearing (37) is equal to H7 and such that the outer diameter (D4) of the centering portion (78) of the second bearing (38) is between g6 and H6.
10. A rotating electric machine according to any of claims 7 to 9, characterized in that the centring portion (78) of the second bearing (38) is formed by a partition projecting in the axial direction and the centring portion (62) of the first bearing (37) is formed by the free end of the cylindrical wall (372), said centring portions being in radial contact with each other to ensure centring of the second bearing (38) with the first bearing (37).
11. The rotating electrical machine according to any of claims 1 to 10, characterized in that the electrical machine (10) comprises at least two fixing portions (68) designed to retain the electrical machine in the motor vehicle, which fixing portions extend protruding from the cylindrical portion (372) of the first bearing (37) on both sides of the shrink-fit zone (Z1).
12. The rotating electrical machine according to any of claims 1 to 11, characterized in that the electrical machine (10) further comprises an electronics module (32) supported by a second bearing (38).
13. A rotating electric machine according to any of claims 1-12, characterized in that the electric machine (10) further comprises a heat insulating seal (65) in the joining area (64) between the first bearing (37) and the second bearing (38).
Technical Field
The present invention relates to a rotating electric machine. The present invention relates to the field of rotating electrical machines, such as electric motors, alternators or alternator starters, or also to reversible electrical machines operable as both motors and generators.
Background
An electrical machine of the alternator type comprises, in a known manner, a housing, and, inside the housing, a rotor with jaws that rotates integrally with a shaft, and a stator that surrounds the rotor in the presence of an air gap.
The stator comprises a body in the form of a set of metal plates provided with recesses for fitting the stator windings. The phase windings of the windings are, for example, three-phase windings which are connected in star or delta form, the outputs of which are connected to an electronic module comprising rectifier elements, such as diodes or transistors.
In the prior art, the housing comprises a bearing in the form of a bowl which centrally comprises a receptacle for receiving a roller bearing for the rotational assembly of the rotor shaft. In addition, one of the bearings supports the electronic module. These bearings are supported on a stator body which is fitted sandwiched between the two bearings, and then referred to as a sandwich construction. The bearing acts as a heat sink, so contact between the body of the stator and the bearing makes it possible to release heat from the stator.
This assembly, which is of the sandwich type, allows a thermal fit between the bearing and the stator, but the height of the thermal fit is limited because of the assembly gap required between the front and rear bearings. In practice, it is not possible to exceed two thirds of the height of the stator body. In addition, the thermal fitting cannot be performed in the passage area of the assembly tie. In addition, in this type of construction, the thermal fit cannot be optimized due to the form of the bearing, and if the clamping is too large, deformation may occur. The contact surface between the bearing and the stator body is thus limited, which correspondingly reduces the heat dissipation surface.
In addition, with this type of sandwich construction, the centering of the bearing relative to the stator is not optimal due to the necessary assembly clearance between the bearing and the stator body. Since the centering is not well controlled, the air gap between the stator and the rotor must be quite large to prevent any risk of contact between the rotor and the stator during operation of the machine.
Insufficient cooling of the motor and an increase in the size of the air gap lead to a reduction in the performance of said motor and even to the risk of poor operation or damage of the motor.
Disclosure of Invention
It is therefore an object of the present invention to ameliorate the aforementioned disadvantages. To this end, the invention relates to a rotating electrical machine for a motor vehicle. According to the invention, the electric machine comprises: a shaft extending along an axis; a rotor mounted on the shaft; a stator surrounding the rotor in the presence of an air gap, the stator including a body provided with a notch and a winding inserted into the notch; a first bearing and a second bearing surrounding an assembly formed by the rotor and the stator. Further according to the invention, the first bearing comprises a transverse flange and a cylindrical wall with an axial orientation obtained from the outer periphery of said flange; and the second bearing comprises a transverse flange enclosing the first bearing, and at least one edge projecting from the flange and forming a joint region with the first bearing. Further in accordance with the present invention, the stator body includes a thermal fit region with the cylindrical wall.
The fact that only one of the bearings is in contact with the stator body makes it possible to improve the cooling of the stator by enlarging the contact surface between these two parts. In fact, the fact that there is no longer a joint area between the two bearings facing the stator makes it no longer possible to be limited by the necessary assembly clearance between the bearings or by the passage of tie rods that fix the two bearings together. The joint area corresponds to the contact area between the two bearings. In addition, this may also improve the centering, in particular the coaxiality, of the bearings with respect to each other, since the intermediate portion is no longer present. Thus, the constraints on the size of the air gap are better controlled and, therefore, the air gap can be reduced.
In addition, the thermal fit relative to simple contact between the stator and the bearing may improve cooling of the stator. In fact, during its operation, the stator tends to expand under the effect of heat and to be intermittently no longer in contact with the bearings. Better cooling can be ensured due to the better clamping provided by the thermal fit.
Furthermore, these forms of bearing, only one of which has a bowl shape and the other of which has a substantially flat form, make it possible to have the stator shrink-fitted on only one of the bearings without increasing the axial dimensions of the machine. In addition, the fact that the second bearing has a substantially flat form makes it possible to avoid the risk of said bearing being deformed by thermal fitting.
The first bearing and the second bearing form a housing that houses the rotor and the stator.
According to an embodiment, each bearing comprises a housing for the rotational assembly of the shaft. In other words, each bearing has an opening that allows the shaft to pass through. For example, roller bearings are provided between the bearings and the shaft to ensure the shaft is rotationally assembled.
According to an embodiment, the ratio of the axial height of the shrink fit region of the first bearing to the axial height of the stator body is 0.9 to 1.2, preferably 1. Thus, for example, the entire axial height of the stator body is shrink-fitted.
According to an embodiment, the difference in diameter between the outer diameter of the stator body and the inner diameter of the cylindrical wall at the hot-fit area is between 0 and 0.7 mm.
According to an embodiment, the edge extends over an axial height smaller than the axial height of the cylindrical wall of the first bearing, for example over a height smaller than one third of the height of said cylindrical wall. In particular, the edge extends over an axial height of about 3 mm.
According to one embodiment, the rim extends discontinuously along the periphery of the flange. For example, the second bearing comprises a plurality of edges forming a plurality of engagement regions with the first bearing, and the electric machine comprises a plurality of openings arranged between two consecutive engagement regions. This allows for the formation of openings between the bearings, which may improve cooling of the motor.
According to an embodiment, the cylindrical wall comprises at least one notch arranged in an axially open manner in a free end of said wall axially opposite the flange, said notch being positioned facing the opening. This makes it possible to enlarge the opening between the bearings, thereby improving cooling. For example, the cylindrical wall includes a plurality of cutouts, each disposed to face the opening.
According to an embodiment, one of the bearings may comprise a pin extending projecting axially towards the other bearing so as to at least partially obstruct the opening. The use of the pin makes it possible to limit the entry of foreign matter into the motor without reducing the size of the opening. Thus, the cooling of the electric machine is increased, while at the same time a good safety of the electric machine with respect to the external environment is ensured. In addition, the use of the pin makes it possible to limit as much as possible the amount of material used to ensure that no foreign matter is inserted inside the motor.
According to an embodiment, the second bearing comprises a plurality of pins.
According to an embodiment, the pin extends axially protruding from the outer circumference of the second bearing.
According to one embodiment, the pin extends over a height shorter than the height of the opening, both heights extending in the same direction. This is in particular the axial direction.
According to an embodiment, the pin has a cross-section in the form of a circle. For example, the pin has a cross section in the form of a convex or curved form. By "rounded form" is meant a form without sharp edges. For example, the pin has an elliptical form in cross section. In another example, the pin has a cross-section in the form of a circle.
According to an embodiment, the longitudinally extending axis of the elliptical form of the pin forms an angle of +10 ° to +70 ° with respect to the radius of the second bearing, the positive direction of which with respect to the radius corresponds to the direction of rotation of the rotor of the rotating electrical machine. This angle is in particular between +30 and +60 °.
According to an embodiment, the pin has a chamfered free end.
All of these pin configurations can optimize the pin form to produce less turbulence behind the pin. This therefore limits the aeronautical noise and the load losses, to optimize the air flow and improve the cooling of the electric machine.
According to an embodiment, the pin extends spaced apart from the first bearing. Therefore, the pin does not contact the first bearing. This makes it possible to limit contact between the bearings, thereby limiting the transfer of heat between the bearings by conduction.
According to an embodiment, the cylindrical wall of the first bearing and the edge of the second bearing each comprise at least one centering portion and at least one fixing portion. The centering portion of the first bearing cooperates with the centering portion of the second bearing. The fixed portion of the first bearing cooperates with the fixed portion of the second bearing. The centering portion and the securing portion form at least one engagement area. By the contact between the bearings, the joint area between the bearings makes it possible to simplify the assembly between the bearings. For example, a small size tie rod may be used, which may reduce weight.
According to an embodiment, the motor comprises a plurality of centering portions and a plurality of fixing portions. For each bearing, each centering portion is disposed to face at least one fixed portion. This makes it possible to limit the contact surface between the first bearing and the second bearing and thus to limit the heat exchange between the parts.
According to an embodiment, the adjustment between the centering portion of the first bearing and the centering portion of the second bearing is defined according to an ISO adjustment system such that the inner diameter of the centering portion of the first bearing is equal to H7 and such that the outer diameter of the centering portion of the second bearing is between g6 and H6.
According to one embodiment, the centring portion of the second bearing is formed by a partition extending in an axial projection, and the centring portion of the first bearing is formed by the free end of the cylindrical wall, said centring portions being in radial contact with each other to ensure that the second bearing is centred in the first bearing pair.
According to an embodiment, each bearing comprises a fixation portion provided with an opening for passage of a fixation unit.
According to an embodiment, each fixing portion extends radially protruding from the respective bearing.
According to an embodiment, the electric machine comprises at least two fixing portions designed to retain the electric machine in the motor vehicle, the fixing portions protruding from the cylindrical portion of the first bearing on either side of the shrink-fit region. Since the fixed portion is provided on a single bearing, assembly tolerances of the motor on the vehicle can be reduced. This may therefore improve the fixation of the electric machine on the vehicle.
According to an embodiment, the electric machine further comprises an electronic module supported by the second bearing. In other words, the electronic module is located on the bearing that is not in contact with the stator body.
According to an embodiment, the electric machine further comprises a heat insulating seal interposed between the first bearing and the second bearing in the joining region. The fact that a seal is placed between the bearings makes it possible not to transfer the heat of the contacting bearing stator to the other bearing, thus limiting the negative thermal influence of the stator on the rest of the machine. This therefore makes it possible to improve the cooling of the rotary electric machine. In addition, the insertion of the seal between the two bearings makes it possible to limit the deformation force between the bearings and also to reduce the magnetic noise due to the disengagement between the two bearings, while ensuring a lower motor production cost.
According to an embodiment, a heat insulating seal may be interposed between two bearings at the junction area of the bearings.
According to an embodiment, the heat insulating seal has an annular form, for example a flat annular form.
According to an embodiment, the heat insulating seal has a return portion extending protruding from the annular portion. The return extends in particular from the outer periphery of the annular portion. For example, the heat insulating seal has a cross-section in the form of an "L".
According to an embodiment, the engagement area comprises a fixing area between the two bearings. For example, each bearing comprises a fixed portion provided with an opening for the passage of the fixed unit. Again, for example, the annular portion extends between the two fixing portions and has an opening for the passage of said fixing unit.
According to an embodiment, the electrical machine further comprises at least one insulating grommet located around the fixation unit extending in the fixation area.
According to one embodiment, the insulating grommet includes a cylindrical portion and an annular portion extending from an end of the cylindrical portion.
According to an embodiment, the heat insulating seal is made of a material selected from one of the following materials: plastic, rubber, elastomer.
According to an embodiment, the heat insulating seal has a thickness of about one millimeter.
According to an embodiment, the winding comprises chignons extending on both sides of the stator body. For example, the bun includes a solid portion and a base between the solid portion and the stator body. The base is formed by an alternation of conductors and openings extending between the solid portion and a recess in the body.
According to an embodiment, the joint area between the first bearing and the second bearing is arranged to radially face a space in the motor, which space is axially between the axial end of one of the buns and the lateral flange of one of the bearings. By having the cooling opening can be positioned facing the bun of the winding, in particular the base of the bun, the cooling of the motor is improved.
According to an embodiment, the rotor comprises at least one fan, in particular centrifugal, fixed at an axial end of the body of said rotor. For example, the rotor includes two centrifugal fans fixed to the axial ends of the main body, respectively.
The rotating electric machine may advantageously form an alternator, an alternator-starter or a reversible electric machine.
The invention will be better understood upon reading the following description and examining the appended drawings. These drawings are provided by way of illustration only and in no way limit the invention.
Drawings
Fig. 1 is a perspective view of a rotary electric machine according to an embodiment of the present invention.
Fig. 2 is a longitudinal sectional view of the rotary electric machine according to the example of fig. 1.
Fig. 3 is a perspective view of a front bearing of the rotating electric machine according to the example of fig. 1.
Fig. 4 is a perspective view of a rear bearing of the rotating electric machine according to the example of fig. 1.
Fig. 5 is a schematic view of a rotating electric machine according to the example of fig. 1.
Fig. 6 is a partial cross-sectional view illustrating an example of a configuration of a heat insulating seal that may be implanted in a joint region between bearings of a rotary electric machine.
Fig. 7 is a view showing the orientation of the pin of the rotary electric machine according to the example of fig. 1, as viewed from above.
Detailed Description
The same, similar or analogous elements remain the same reference in the various figures. In addition, the front element is located on the free end side of the shaft designed to support the pulley, while the rear element is located on the opposite side, i.e. on the side of the electronic control module.
Fig. 1 and 2 show a compact polyphase rotary
The
In the following description, the terms axial, radial, external and internal refer to an axis X passing through the
For example, as shown in fig. 2, the
The
The phase outputs of the
In addition, the
As shown in fig. 3, the generally bowl-shaped front bearing 37 includes a
The
As shown in fig. 4, the
The
The
For example, the
The
According to an embodiment, the
As shown in FIG. 7, the longitudinally extending axis X1 of the elliptical form of the
For example, each pin has a chamfered free end, so that only the free end of the pin has a generally conical form, and the portion of the pin extending between the free end and the
In all cases, the
According to a variant embodiment not shown, both the
As shown in fig. 1 and 2, the
As can be seen from fig. 2 and 5, the ratio of the height L1 of the shrink fit zone Z1 of the
In addition, as shown in fig. 5, the difference between the outer diameter D2 of the
The
In this embodiment, each
For example, each fixed
As schematically represented in fig. 5, the adjustment between the centering
These characteristics H7, g6 and H6 lead to acceptable tolerance limits during bearing production. For a reference temperature of 20 ℃, when the inner diameter D3 is between 120mm and 180mm, H7 corresponds to a tolerance value between 0 and +40 μm, g6 corresponds to a tolerance value between-14 μm and-39 μm, and H6 corresponds to a tolerance value between 0 and-25 μm. Thus, for example, when the inner diameter D3 is between 139mm and 139.4mm, the outer diameter D4 is between 139mm and 138.61 mm. Typically, the outer diameter D4 is between 120mm and 180 mm.
For example, the centering
As shown in fig. 6, the contact surface between the two
In the example shown here, the
According to another embodiment, not shown, heat-insulating seals may be provided between the
The insulating
As a variant, as shown in broken lines in fig. 3, the centring portion can be constituted by a
In the example of fig. 2, a
In this case, the
Also, in the embodiment shown here, the
As shown in fig. 3, the
It is to be understood that the above description has been provided by way of example only and is not limiting on the field of the invention, and that no deviation from the invention will be constituted by the replacement of different elements by any other equivalent. Furthermore, different features, variations and/or embodiments of the invention may be associated with each other according to various combinations, as long as they are not incompatible or mutually exclusive.