JP2013126280A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine in which a contact time when a stator is contacted with coolant is secured, heat of the stator is sufficiently transferred to the coolant, and deterioration of cooling efficiency can be prevented.SOLUTION: A rotary electric machine includes a wide projection 222g formed on a radial external peripheral surface 222c of an annular stator 222 supported by a motor case 21 supporting a rotor shaft (input axis) 24 substantially in a horizontal state. The wide projection 222g has a prescribed dimension in a circumferential direction based on a central part L2 in a vertical direction of the stator 222 and extends in an axial direction. The wide projection 222g narrows a gap size of an annular clearance 26 disposed between an inner peripheral surface 213b of the motor case 21 and the radial external peripheral surface 222c of the stator 222 in which coolant flows down by its own weight.

Description

  The present invention relates to a rotating electrical machine that cools the periphery of a rotor.

  2. Description of the Related Art Conventionally, a rotating electrical machine is known in which an annular coolant passage is provided between a stator and a motor case, and the stator is cooled by coolant flowing through the coolant passage (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2007-202234

  However, in the conventional rotating electric machine, when the rotor shaft is installed in a horizontal state and the coolant supplied from the upper part along the coolant passage is circulated by its own weight, the inclination of the tangential plane is close to vertical. In the central part in the vertical direction, the flow rate of the cooling water increases. For this reason, there is a problem that heat generated in the stator cannot be sufficiently transmitted to the cooling liquid, and cooling efficiency is lowered.

  The present invention has been made paying attention to the above-mentioned problem, and aims to provide a rotating electrical machine capable of ensuring contact time between the stator and the coolant and sufficiently transferring the heat of the stator to the coolant. To do.

In order to achieve the above object, the rotating electrical machine of the present invention includes a motor case, a rotor, a stator, a coolant supply part, an annular gap part, and a wide protrusion part.
The motor case supports the rotor shaft in a substantially horizontal state.
The rotor can rotate integrally with the rotor shaft.
The stator has an annular shape, is supported by the motor case, and is disposed on a radially outer peripheral portion of the rotor.
The cooling liquid supply unit is formed at an upper portion of the motor case and supplies a cooling liquid for cooling the stator.
The annular gap is provided between the inner peripheral surface of the motor case and the outer peripheral surface in the radial direction of the stator, and communicates with the cooling liquid supply unit so that the cooling liquid flows down by its own weight.
The wide projecting portion is provided on a radially outer peripheral surface of the stator, has a predetermined dimension in the circumferential direction with respect to a substantially central portion in the vertical direction, and extends in the axial direction so as to have a clearance dimension of the annular clearance portion. Narrow.

In the rotating electrical machine of the present invention, the annular protrusion provided between the inner peripheral surface of the motor case and the radial outer peripheral surface of the stator is caused by the wide protrusion provided on the radially outer peripheral surface of the stator. Among them, the gap size is narrowed in a predetermined region in the circumferential direction and the axial direction with reference to a substantially central portion in the vertical direction.
In other words, in the annular gap portion, the tangential plane has an inclination close to the vertical at substantially the center in the vertical direction. For this reason, the flow velocity (flow velocity) of the cooling liquid flowing down by its own weight becomes faster at the substantially central portion in the vertical direction of the annular gap portion. On the other hand, by providing a wide protrusion on the stator and narrowing the gap size in the substantially central part in the vertical direction of the annular gap, the flow of the cooling liquid flowing down by its own weight is inhibited, and the flow speed of the cooling liquid is suppressed. be able to.
As a result, the contact time between the stator and the coolant can be secured, and the heat of the stator can be sufficiently transmitted to the coolant to prevent the cooling efficiency from being lowered.

It is a longitudinal cross-sectional view which shows the in-wheel motor unit to which the electric motor (rotary electric machine) of Example 1 was applied. 1 is a transverse cross-sectional view showing an electric motor of Example 1. FIG. It is principal part sectional drawing of the electric motor of Example 1, (a) shows a coolant supply part, (b) shows a coolant discharge part. It is an external appearance perspective view which shows the stator of Example 1. FIG. It is an enlarged view of the A section in FIG. It is a cross-sectional view which shows the electric motor (rotating electric machine) of Example 2. FIG. It is an external appearance perspective view which shows the stator of Example 2. FIG. It is a longitudinal cross-sectional view which shows the in-wheel motor unit to which the electric motor (rotary electric machine) of Example 3 was applied. It is a cross-sectional view showing an electric motor of Example 3. 6 is an external perspective view showing a stator of Example 3. FIG. It is explanatory drawing which shows the force which acts between the stator of Example 3, and a motor case. It is a longitudinal cross-sectional view which shows the in-wheel motor unit to which the electric motor (rotary electric machine) of Example 4 was applied. FIG. 6 is a cross-sectional view showing a stator and a seal member of Example 4. It is explanatory drawing explaining the dimension relationship at the time of incorporating a stator in a motor case.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the rotary electric machine of this invention is demonstrated based on Example 1-Example 4 shown in drawing.

  First, the configuration of the rotating electrical machine according to the first embodiment will be described by dividing it into “a configuration of an application example of a rotating electrical machine” and “a configuration of a rotating electrical machine”.

[Configuration of application example of rotating electrical machine]
FIG. 1 is a longitudinal sectional view showing an in-wheel motor unit to which the electric motor (rotating electric machine) according to the first embodiment is applied.

  The in-wheel motor unit MU shown in FIG. 1 is mounted on a vehicle (not shown) as a travel drive source, and includes a wheel 10, an electric motor (rotating electric machine) 20, and a hub bearing 30.

The wheel 10 includes a tire 11 and a wheel 12 that is disposed inside the tire 11 and holds the tire 11.
A brake disc 13 provided with a brake 13A and a wheel hub 14 integrated with an output shaft 25 of the electric motor 20 are attached to the vehicle inner side of the wheel 12 (left side in FIG. 1). It is fixed in a state where it is stacked concentrically.

  The electric motor 20 is disposed inside the vehicle of the wheel 10 and individually drives and brakes the wheel 10.

  The hub bearing 30 is disposed between the output shaft 25 of the electric motor 20 and the motor case 21, and supports the output shaft 25 rotatably with respect to the motor case 21. The hub bearing 30 includes an outer race 31 fixed to the motor case 21, an inner race 32 fixed to the output shaft 25, and a plurality of rolling elements 33 interposed between the outer race 31 and the inner race 32. Have.

[Configuration of rotating electric machine]
FIG. 2 is a cross-sectional view illustrating the electric motor according to the first embodiment. FIG. 3 is a cross-sectional view of a main part of the electric motor according to the first embodiment, where (a) shows a coolant supply unit and (b) shows a coolant discharge unit. FIG. 4 is an external perspective view showing the stator of the first embodiment. FIG. 5 is an enlarged view of a portion A in FIG.

  The electric motor 20 includes a motor case 21, a motor part 22 including a rotor 221 and a stator 222, and a speed reducer part 23.

The motor case 21 incorporates the motor part 22 and the speed reducer part 23, and has an input shaft (rotor shaft) 24 rotated by the motor part 22, an output shaft 25 protruding from the speed reducer part 23, Is supported horizontally. The motor case 21 is held by a suspension mechanism 35 so as to be swingable with respect to a vehicle body (not shown). Further, the motor case 21 includes a coolant supply part 21A for supplying a coolant for cooling the stator 222 to an annular gap part 26 provided between the stator 222 and the motor case 21, and an inside of the annular gap part 26. And a coolant discharge portion 21B for discharging the coolant.
The motor case 21 includes a case portion 211 in which the motor portion 22 and the speed reducer portion 23 are coaxially arranged and housed, and a cover portion 212 that covers the vehicle inside of the case portion 211 (left side in FIG. 1). doing. Here, the case portion 211 and the cover portion 212 are combined with each other to constitute the motor case 21.

The case portion 211 has a cylindrical shape with both ends open, one opening is covered with a cover portion 212, and the outer race 31 of the hub bearing 30 is fitted into the other opening.
Three suspension attachment portions 214 for attaching the suspension mechanism 35 are formed on the outer peripheral surface 213a of the case portion 211 here. The suspension mounting portion 214 generally requires rigidity and is thick. The suspension mechanism 35 is attached via an attachment bolt 36 that penetrates the suspension attachment portion 214.
Three groove portions 215 are formed on the inner peripheral surface 213b of the case portion 211 so that the upper support protrusion portion 222e and the lower support protrusion portion 222f formed on the stator 222 of the motor portion 22 are in contact with each other.

  One groove portion 215 is formed at a position facing the topmost portion of the stator 222, and one groove portion 215 is formed at two positions facing each other at positions symmetrical to the circumferential direction around the bottommost portion of the stator 222. Moreover, the cross-sectional shape of each groove part 215 corresponds with the cross-sectional shape of the upper support protrusion part 222e and the lower support protrusion part 222f, and is formed in the circular arc shape where a cross section becomes a semicircle here. The groove 215 is formed by a cylindrical cutting process such as an end mill.

  And the formation position of the said suspension attaching part 214 and the formation position of the said groove part 215 are substantially corresponded in radial direction. That is, the suspension attachment portion 214 is provided in accordance with the positions of the upper support protrusion 222e and the lower support protrusion 222f.

  The cover portion 212 has a disk shape covering the opening of the case portion 211, and a cylindrical portion 212a into which one end of the input shaft 24 is inserted is formed at the center of the inner surface. A first bearing 24A that rotatably supports the input shaft 24 is provided inside the cylindrical portion 212a.

  The coolant supply part 21A has a supply path 21Aa that penetrates the case part 211 and the cover part 212, and a supply port 21Ab that opens to the inner peripheral surface 213b of the case part 211 and communicates with the annular gap part 26. doing. Further, a pair of the coolant supply parts 21A are provided at positions on the upper part of the motor case 21 that are symmetrical in the circumferential direction around the upper support protrusion 222e. That is, the coolant supply part 21A is provided on both sides in the circumferential direction of the groove part 215 with which the upper support protrusion 222e is fitted and contacted. The supply path 21Aa of the coolant supply unit 21A protrudes from the motor case 21 and is connected to a coolant pump (not shown).

  The coolant discharge part 21 </ b> B has a discharge path 21 </ b> Ba that penetrates the case part 211 and a discharge port 21 </ b> Bb that opens to the annular gap part 26. Here, the discharge port 21Bb is formed by partially denting the inner peripheral surface of the cover portion 212 and partially cutting away the contact between the cover portion 212 and the axial end surface 222d of the stator 222. Further, a pair of the coolant discharge parts 21B is provided at a position below the motor case 21 and on the upper side in the circumferential direction from the lower support protrusion 222f. That is, the coolant discharge part 21B is provided on the upper side in the circumferential direction of the groove part 215 with which the lower support protrusion part 222f is fitted and brought into contact. The discharge path 21Ba of the coolant discharge part 21B protrudes from the motor case 21 and is connected to a coolant pump (not shown).

  The motor unit 22 includes a cylindrical rotor 221 that can rotate integrally with the input shaft 24, and an annular stator 222 disposed on a radially outer peripheral portion of the rotor 221.

The rotor 221 has a flange portion 221a, a laminated steel plate 221b, and a permanent magnet 221c.
The flange portion 221a protrudes from the input shaft 24 in the radial direction. The laminated steel plate 221b is fixed to the outer periphery of the flange portion 221a. The permanent magnets 221c are embedded in the vicinity of the outer peripheral surface of the laminated steel plate 221b and are arranged at regular intervals in the circumferential direction.

The stator 222 is supported by the motor case 21 and has a cylindrical stator body 222a having a large number of teeth protruding from the inner peripheral surface toward the rotor 221, and a coil 222b wound around the teeth of the stator body 222a. ,have. Further, on the radially outer peripheral surface 222c of the stator body 222a, there are an upper support protrusion 222e, a pair of lower support protrusions 222f and 222f, and a pair of wide protrusions 222g facing each other across the central axis of the stator 222. 222 g is formed.
The upper support protrusion 222e and the pair of lower support protrusions 222f and 222f are fitted and contacted with a plurality of grooves 215 formed in the case part 211, respectively. Further, the axial end surfaces 222d and 222d on both sides in the axial direction of the stator body 222a are in contact with the case portion 211 and the cover portion 212 of the motor case 21, respectively, and are sandwiched between the case portion 211 and the cover portion 212. . Accordingly, the stator 222 is supported on the motor case 21.
At this time, an annular clearance 26 is provided between the inner peripheral surface 213b of the case portion 211 of the motor case 21 and the radial outer peripheral surface 222c of the stator body 222a.

  The annular gap portion 26 is a gap along the radially outer peripheral surface 222c, communicates with the supply port 21Ab of the coolant supply portion 21A, and the coolant flowing into the motor case 21 from the coolant supply portion 21A has its own weight. Flow down. In addition, the annular gap portion 26 communicates with a discharge port 21Bb of the coolant discharge portion 21B, and the coolant that has flowed down through the annular gap portion 26 is discharged out of the motor case 21 through the discharge port 21Bb. The

  The upper support protrusion 222e is formed to project in an arc shape so that the cross section is semicircular at the topmost portion of the stator 222, and extends in the axial direction of the stator 222. The “topmost part” is a part that is the uppermost in the vertical direction L1 when the stator 222 is supported in the horizontal direction. The upper support protrusion 222e extends over the entire length from one axial end surface 222d of the stator body 222a to the other axial end surface 222d. That is, the axial dimension of the upper support protrusion 222e is the same as the axial dimension of the stator body 222a.

  A pair of the lower support protrusions 222f are formed at positions that are symmetrical in the circumferential direction around the bottom, between the bottom of the stator 222 and the wide protrusion 222g. The lower support protrusion 222f is formed to protrude in an arc shape so that the cross section is a semicircular shape, and extends in the axial direction of the stator 222. The “bottom part” is a part that is the lowest in the vertical direction L1 when the stator 222 is supported in the horizontal direction. The lower support protrusion 222f extends over the entire length from one axial end surface 222d of the stator body 222a to the other axial end surface 222d. That is, the axial dimension of the lower support protrusion 222f is the same length as the axial dimension of the stator body 222a.

The wide protrusion 222g is a bulging portion that protrudes from the radially outer circumferential surface 222c, has a predetermined dimension in the circumferential direction with respect to the vertical central portion L2 of the stator 222, and extends in the axial direction. Has been. That is, the wide protrusion 222 g extends in the vertical direction about the vertical center portion L <b> 2 of the stator 222, and the upper surface 222 h has a certain area facing the inner peripheral surface 213 b of the case portion 211. Here, the circumferential dimension of the wide protrusion 222g is arbitrarily set according to the amount of coolant supplied to the annular gap 26, the flow rate of coolant, and the like. As shown in FIG. 4, the wide protrusion 222g extends over the entire length from one axial end surface 222d of the stator body 222a to the other axial end surface 222d. That is, the axial dimension of the wide protrusion 222g is the same as the axial dimension of the stator body 222a.
The wide protrusion 222g has a height smaller than the gap dimension W1 of the annular gap 26, and the gap of the annular gap 26 is narrowed by the wide protrusion 222g. That is, a narrow gap 222i having a gap dimension W2 smaller than the gap dimension W1 of the annular gap 26 is formed between the upper surface 222h of the wide protrusion 222g and the inner peripheral surface 213b of the motor case 21. (See FIG. 5).

  The reduction gear unit 23 is provided between the input shaft 24 and the output shaft 25. As shown in FIG. 1, the speed reducer portion 23 is fixed to the sun gear 23 a formed on the input shaft 24 and an inner peripheral surface 213 b of the case portion 211 so as to allow only slight swinging by a projection claw not shown. A ring gear (internal gear) 23b, three pinions 23c (only one is shown here) meshed with the sun gear 23a and the ring gear 23b, and the pinions 23c are arranged at equal intervals in the circumferential direction and rotatably supported. At the same time, the output shaft 25 is constituted by a planetary gear set having a carrier 23d integrally formed.

  The motor case 21 contains lubricating oil for the purpose of cooling the motor portion 22 and lubricating the speed reducer portion 23. An oil seal O is provided between the carrier 23d and the outer race 31 of the hub bearing 30 to prevent the lubricating oil from flowing out.

  Next, the “suppressing action of the coolant passage speed” in the rotating electrical machine of the first embodiment will be described.

[Inhibition of coolant passage speed]
In the in-wheel motor unit MU of the first embodiment, the cooling liquid that cools the stator 222 is supplied into the annular gap 26 through the supply port 21Ab via the supply path 21Aa of the coolant supply part 21A.
At this time, since the coolant supply part 21 </ b> A is provided in the upper part of the motor case 21, the coolant supplied to the annular gap part 26 flows down along the radial outer peripheral surface 222 c of the stator 222 due to its own weight. Then, the coolant flowing down to the lower side of the annular gap 26 is led out of the annular gap 26 from the outlet 21Bb of the coolant outlet 21B provided at the lower part of the motor case 21, and passes through the discharge path 21Ba. Then, it is sucked into a coolant pump (not shown) provided outside the motor case 21 as it is.

Here, the annular gap portion 26 has a tangential plane whose inclination is nearly vertical, and the flow velocity (flow velocity) of the coolant flowing down by its own weight is increased at the substantially central portion in the vertical direction. On the other hand, in the electric motor 20 according to the first embodiment, the wide protrusion 222g is formed to protrude from the radial outer peripheral surface 222c of the stator body 222a within a predetermined range in the circumferential direction with reference to the vertical central portion L2. Yes. Therefore, in the portion where the upper surface 222h of the wide protrusion 222g faces the inner peripheral surface 213b of the case portion 211, a narrow gap 222i having a gap dimension W2 smaller than the gap dimension W1 of the annular gap 26 is formed. The cross-sectional area of the flow path through which the liquid flows is reduced.
That is, in the portion where the flow velocity (flow velocity) of the coolant becomes high, the narrow gap portion 222i becomes resistance to the flow of the coolant flowing down by its own weight, and the flow velocity of the coolant flowing down the annular gap portion 26 is suppressed.

  Thereby, the coolant supplied from the upper part of the motor case 21 fills the narrow gap portion 222i and the annular gap portion 26 above the narrow gap portion 222i, and ensures the contact time between the stator 222 and the coolant. be able to. Then, sufficient heat transfer from the stator 222 to the coolant can be performed, and a decrease in cooling efficiency of the stator 222 can be prevented.

The wide protrusion 222g has a predetermined dimension in the circumferential direction with respect to the vertical center portion L2 of the stator 222 and extends in the axial direction. That is, the size (area) of the narrow gap 222i is changed by adjusting the circumferential dimension and the axial dimension of the wide protrusion 222g according to the flow rate of the coolant supplied to the annular gap 26, and cooling is performed. The flow rate of the liquid can be set appropriately.
In addition, on the premise that the cooling liquid is filled in the narrow gap part 222i and the annular gap part 26 above the narrow gap part 222i, the circumferential dimension of the wide protrusion part 222g in which the amount of discharged cooling liquid increases as much as possible, The axial dimension is the optimum condition for making the flow rate of the coolant appropriate.

  Further, the coolant supplied to the annular gap portion 26 stays on the outer periphery of the stator 222 against gravity and supply pressure, so that the coolant per unit time is not deteriorated without deteriorating the heat exchange efficiency from the stator 222. This will save the flow rate. As a result, the energy for circulating the coolant can be reduced, and the highly efficient electric motor 20 can be obtained.

  Furthermore, as a secondary effect, the coolant is filled in the narrow gap portion 222 i and the annular gap portion 26 above the narrow gap portion 222 i, so that the stator 222 is driven by electromagnetic force generated when the rotor 221 is driven. Even when the motor vibrates slightly, the damper effect is exhibited by the filled coolant. Thereby, a part of the vibration energy of the stator 222 is absorbed and this vibration energy is attenuated, so that the electric motor 20 can be made quiet with relatively little vibration.

  The wide protrusion 222g is formed to protrude from the radially outer peripheral surface 222c of the stator body 222a, so that the outer diameter (back core thickness) of the stator body 222a at the wide protrusion 222g is increased. As a result, the rigidity of the stator body 222a is improved, and a vibration suppressing effect can be obtained.

In the electric motor 20 of the first embodiment, the upper support protrusion 222e that contacts the inner peripheral surface 213b of the case portion 211 of the motor case 21 is formed to protrude from the top of the stator 222, and the upper support protrusion 222e is the center. A pair of coolant supply units 21A are provided at positions that are symmetrical in the circumferential direction.
Therefore, two paths for flowing the coolant through the annular gap portion 26 can be secured separately in the circumferential direction across the vertical direction L1. And compared with the case where the whole circumference | surroundings of the stator 222 are passed in one path | route, the flowing-down path | route length of a coolant can be shortened. As a result, the coolant whose temperature has risen due to heat exchange with the stator 222 can be discharged smoothly, and the cooling efficiency can be improved.

In the electric motor 20 according to the first embodiment, the stator 222 includes the upper support protrusion 222e that contacts the inner peripheral surface 213b of the case portion 211 of the motor case 21 and the pair of lower support on the radial outer peripheral surface 222c of the stator body 222a. It has a protrusion 222f. At this time, the upper support protrusion 222 e is provided on the topmost portion of the stator 222. The pair of lower support protrusions 222 f are provided at positions that are symmetrical in the circumferential direction with the bottom of the stator 222 as the center.
Thereby, the annular clearance 26 having a certain size can be easily and reliably formed between the upper support protrusion 222e and the lower support protrusion 222f. In addition, since the contact area between the stator 222 and the motor case 21 can be reduced, when the stator 222 slightly vibrates due to the electromagnetic force generated when the motor unit 22 is driven, the stator 222 directly contacts the motor case 21. The absolute value of the transmitted vibration energy can be reduced.

In the first embodiment, the upper support protrusion 222e and the lower support protrusion 222f extend in the axial direction, and each axial dimension thereof is the same length as the axial dimension of the stator body 222a.
Therefore, the stator 222 can be stably supported with respect to the motor case 21, and the coolant supplied to the annular gap portion 26 can be prevented from leaking out of the annular gap portion 26.

Furthermore, the electric motor 20 according to the first embodiment is applied to an in-wheel motor unit MU disposed on the vehicle inner side of the wheel 12 that supports the wheel 10, and is swingably held on the vehicle body via the suspension mechanism 35. Three suspension mounting portions 214 for attaching the suspension mechanism 35 are formed on the outer peripheral surface 213a of the case portion 211 of the motor case 21 in accordance with the positions of the upper support protrusion 222e and the pair of lower support protrusions 222f. ing.
Therefore, the stator 222 is supported in the motor case 21 by a thick portion that requires rigidity. Thereby, the drive reaction force generated in the stator 222 can be reliably received by the motor case 21. Further, even when the stator 222 slightly vibrates due to the electromagnetic force generated when the motor unit 22 is driven, the vibration energy can be reliably received by the motor case 21 and can be suppressed. A quiet electric motor 20 can be obtained.

Next, the effect will be described.
In the rotating electrical machine of the first embodiment, the following effects can be obtained.

(1) a motor case 21 that supports the rotor shaft (input shaft) 24 in a substantially horizontal state;
A rotor 221 rotatable integrally with the rotor shaft 24;
An annular stator 222 supported by the motor case 21 and disposed on the outer periphery in the radial direction of the rotor 221;
A coolant supply part 21A formed on the motor case 21 for supplying a coolant for cooling the stator 222;
An annular gap portion 26 provided between the inner peripheral surface 213b of the motor case 21 and the radial outer peripheral surface 222c of the stator 222, communicating with the coolant supply portion 21A and allowing the coolant to flow under its own weight;
Projectingly formed on the radially outer peripheral surface 222c of the stator 222, has a predetermined dimension in the circumferential direction with reference to the central portion L2 in the vertical direction, and extends in the axial direction to have a clearance dimension W1 of the annular clearance 26. A wide protrusion 222g for narrowing;
It was set as the structure provided with.
For this reason, the contact time between the stator 222 and the coolant is ensured, and the heat of the stator 222 can be sufficiently transmitted to the coolant, thereby preventing the cooling efficiency from being lowered.

(2) The stator 222 has an upper support protrusion 222e that protrudes from the top of the radially outer peripheral surface 222c and contacts the inner peripheral surface 213b of the motor case 21,
A pair of the coolant supply parts 21A is provided at positions that are symmetrical in the circumferential direction around the upper support protrusion 222e.
For this reason, two paths for flowing the coolant through the annular gap 26 are secured in the circumferential direction with the vertical direction L1 interposed therebetween. Compared with the case where the entire circumference of the stator 222 is routed by one path, It is possible to smoothly discharge the warmed coolant by shortening the flow path length and exchanging heat, thereby improving the cooling efficiency.

(3) The stator 222 is formed so as to protrude from the top of the radially outer peripheral surface 222c, and an upper support protrusion 222e that contacts the inner peripheral surface 213b of the motor case 21;
A pair of lower support protrusions 222f that are formed so as to protrude symmetrically in the circumferential direction around the bottom of the radially outer peripheral surface 222c, and are in contact with the inner peripheral surface 213b of the motor case 21;
It was set as the structure which has.
For this reason, it is possible to easily and reliably form the annular gap portion 26 having a certain size between the stator 222 and the case portion 211.

(4) The motor case 21 is disposed on the vehicle inner side of the wheel 12 that supports the wheel 10, and is held swingably on the vehicle body via the suspension mechanism 35.
A suspension mounting portion 214 for attaching the suspension mechanism 35 is provided on the outer peripheral surface 213a of the motor case 21 in accordance with the positions of the upper support protrusion 222e and the lower support protrusion 222f.
For this reason, the stator 222 is supported by the relatively rigid portion of the motor case 21, and the driving reaction force generated in the stator 222 can be reliably received by the motor case 21.

  Example 2 is an example in which small protrusions are provided between the wide protrusions and the upper support protrusions and between the wide protrusions and the lower support protrusions.

First, the configuration will be described.
FIG. 6 is a cross-sectional view illustrating the electric motor (rotating electric machine) according to the second embodiment. FIG. 7 is an external perspective view showing the stator of the second embodiment.

  The stator 422 in the electric motor (rotating electric machine) 40 according to the second embodiment includes an upper support protrusion 422e, a pair of lower support protrusions 422f and 422f, and a center axis of the stator 422 on the radially outer peripheral surface 422c of the stator body 422a. A pair of wide protrusions 422g, 422g and a plurality of small protrusions 422j that are opposed to each other are formed.

  Since the structures of the upper support protrusion 422e, the lower support protrusion 422f, and the wide protrusion 422g are the same as those in the first embodiment, detailed description thereof is omitted.

  The small protrusions 422j are provided at the upper and lower positions in the circumferential direction of the wide protrusion 422g. That is, a plurality of small protrusions 422j are provided between the upper support protrusion 422e and the wide protrusion 422g, and between the lower support protrusion 422f and the wide protrusion 422g.

The small protrusion 422j is a protrusion having a smaller circumferential dimension and axial dimension than the wide protrusion 422g, and the area where the upper surface 422k of the small protrusion 422j faces the inner peripheral surface 413b of the motor case 41 is as follows. The upper surface 422h of the wide protrusion 422g is smaller than the area facing the inner peripheral surface 413b.
And this small projection part 422j has height smaller than the clearance dimension W1 of the annular clearance part 46, and the clearance dimension of the annular clearance part 46 is narrowed by this small projection part 422j.

  Next, the operation will be described.

  In the electric motor (rotary electric machine) 40 of the second embodiment, when the coolant is supplied from the coolant supply part 41A, the coolant flowing into the annular gap part 46 from the supply port 41Ab causes the annular gap part 46 to be moved by its own weight. Flow down.

  Here, a plurality of small protrusions 422j are formed between the upper support protrusion 422e and the wide protrusion 422g and between the wide protrusion 422g and the lower support protrusion 422f. When the coolant flowing down the annular gap 46 comes into contact with the side surface of the small protrusion 422j, the flow is inhibited and the flow down speed is reduced. Further, since the clearance dimension of the annular clearance 46 is narrowed by the small protrusion 422j, the amount of the coolant that passes between the small protrusion 422j and the inner peripheral surface 413b of the motor case 41 is also limited. That is, by providing the small protrusion 422j, the flow path cross-sectional area of the coolant in the annular gap 46 is changed.

As a result, when the coolant flows down the annular gap 46, the flow velocity is reduced by the small protrusions 422j. That is, the coolant supplied from the coolant supply part 41A reaches the narrow gap 422i by the wide protrusion 422g while gradually decreasing the flow down speed, and the coolant that has passed through the narrow gap 422i further decreases the flow down speed. It reaches the discharge port 41Bb of the coolant discharge part 41B while dropping.
As described above, the flow rate of the coolant flowing through the annular gap 46 can be adjusted by the small protrusion 422j. Then, the cooling liquid fills the upper side of the wide protrusion 422g and exhibits a vibration damping effect, and is received from the stator 422, which is the discharge time of the cooling liquid that has passed through the narrow gap 422i formed by the wide protrusion 422g. It is possible to set the function of discharging the heat to the outside optimally in a balanced manner.

  Further, in the electric motor (rotating electric machine) 40 according to the second embodiment, a plurality of small protrusions 422j are formed on the radial outer peripheral surface 422c of the stator body 422a in addition to the wide protrusions 422g. The surface area of 422c can be increased. For this reason, the area where the stator 422 comes into contact with the coolant is increased, the function of releasing heat from the stator 422 (cooling performance) can be improved, and the efficiency of heat exchange with the coolant can be improved.

  Furthermore, by forming the small protrusions 422j, it is possible to reinforce between a large number of teeth protruding toward the rotor 421 from the inner peripheral surface of the stator body 422a. Thereby, the vibration mode of the stator 422 can be adjusted, and the sound vibration performance can be improved.

Next, the effect will be described.
In the rotating electrical machine of the second embodiment, the following effects can be obtained.

(5) The stator 422 is provided at a circumferential upper position and a circumferential lower position of the wide protrusion 422g, and has a plurality of small protrusions 422j whose circumferential dimensions and axial dimensions are smaller than the wide protrusion 422g. It was set as the structure which has.
For this reason, it is possible to finely adjust the flow rate of the coolant flowing through the annular gap 46 by the small protrusions 422j, and the flow rate of the coolant can be set more appropriately.

  Example 3 is an example in which a coolant reservoir is formed in the lower part of the motor case and the coolant is circulated using a circulation pump.

First, the configuration will be described.
FIG. 8 is a longitudinal sectional view showing an in-wheel motor unit to which the electric motor (rotating electric machine) of the third embodiment is applied. FIG. 9 is a cross-sectional view illustrating the electric motor according to the third embodiment. FIG. 10 is an external perspective view showing the stator of the third embodiment. In addition, about the structure similar to the said Example 1, the code | symbol same as Example 1 is attached | subjected and description is abbreviate | omitted.

  The electric motor (rotary electric machine) 50 according to the third embodiment includes an oil pump (circulation pump) 58 that circulates the coolant in the motor case 51, and an oil reservoir (coolant reservoir) at the lower portion of the motor case 51. 57 is provided. Further, in the third embodiment, hydraulic fluid such as ATF that can be used for lubricating the rotor 521 and the speed reducer unit 23 is used as the coolant.

  The oil pump 58 is provided outside the motor case 51 and has an oil suction port 58A and an oil discharge port 58B. A suction pipe 59 a having one end communicating with the oil reservoir 57 is connected to the oil suction port 58 </ b> A. A discharge pipe 59b having one end branched is connected to the oil discharge port 58B. One of the branched branches of the discharge pipe 59b is a lubrication pipe 59c communicating with the inside of the cylindrical part 512a formed in the cover part 512 of the motor case 51. The other of the branched branches of the discharge pipe 59b is a cooling pipe 59d that communicates with the supply path 51Aa of the coolant supply section 51A. In the lubrication pipe 59c and the cooling pipe 59d, there are respectively provided throttles S for limiting the inner diameter of the pipe in order to properly distribute the cooling liquid.

  The oil reservoir 57 is a space in the motor case 51 provided below the stator 522, and is a portion for storing the cooled and lubricated coolant. The oil reservoir 57 communicates with a discharge path 51Ba having a discharge port 51Bb opened to the annular gap 56. In addition, the oil level (maximum oil storage height) OL of the coolant stored in the oil reservoir 57 enables the lower part of the stator 522 to be immersed in the coolant and slightly contacts the outer peripheral surface 521a of the rotor 521. Set to degree. Further, the discharge port 51Bb is formed at substantially the same height as the oil level OL.

Furthermore, in the electric motor (rotating electric machine) 50 of the third embodiment, the upper support protrusion 522e and the pair of lower support protrusions 522f formed on the radial outer peripheral surface 522c of the stator body 522a of the stator 522 The top portion 522k facing the inner peripheral surface 513b of the case portion 511 is a flat surface.
That is, in each of the support protrusions 522e and 522f, in the above-described first and second embodiments, the top portion is curved in an arc shape in the convex direction so that the cross section is a semicircular shape. In No. 3, the top part curved in the shape of an arc is cut out to form a flat surface.

On the other hand, the groove portion 515 formed in the case portion 511 is formed by a cylindrical cutting process such as an end mill, and is formed in an arc shape having a semicircular cross section.
Thereby, when the upper support protrusion 522e and the pair of lower support protrusions 522f are fitted and contacted with the groove 515, both side surfaces 522m and 522m in the circumferential direction of the support protrusions 522e and 522f are in contact with the groove 515 and are flat. A gap K is formed between the top portion 522k and the groove portion 515 which are the surfaces.

  Next, the operation will be described.

  In the electric motor (rotary electric machine) of the third embodiment, when the coolant is supplied from the coolant supply part 51A, the coolant flowing into the annular gap part 56 from the supply port 51Ab flows down the annular gap part 56 by its own weight. To do. During the flow of the cooling liquid, the flow speed is limited by the narrow gap portion 522i formed by the wide protrusion 522g, thereby sufficiently exchanging heat with the stator 522 to cool the stator 522. Then, the oil flows out from the discharge port 51Bb to the oil reservoir 57 through the discharge path 51Ba.

  The coolant flowing into the oil reservoir 57 cools a part of the stator 522 immersed in the coolant in the oil reservoir 57, and is sucked into the oil pump 58 and outside the motor case 51 via the suction pipe 59a. To leak.

Then, the coolant sucked into the oil pump 58 from the suction pipe 59a through the oil suction port 58A is discharged from the oil discharge port 58B and circulated in the motor case 51 through the discharge pipe 59b.
At this time, the coolant that has flowed into the lubrication pipe 59c lubricates the first bearing 54A provided in the cylindrical portion 512a, and each gear of the speed reducer portion 23 via an oil passage formed in the input shaft 54. To be supplied. On the other hand, the coolant that has flowed into the cooling pipe 59d flows into the supply path 51Aa of the coolant supply portion 51A, and is supplied again to the annular gap portion 56.

  As described above, in the electric motor (rotating electric machine) according to the third embodiment, the oil reservoir 57 that allows the lower part of the stator 522 to be immersed in the coolant is provided in the lower part of the motor case 51 and communicates with the annular gap part 56. The discharge port 51Bb of the coolant discharge part 51B thus formed is formed at substantially the same height as the oil level of the coolant stored in the oil reservoir 57.

  As a result, the stator 522 positioned above the discharge port 51Bb is appropriately cooled by the coolant flowing under its own weight through the annular gap portion 56. On the other hand, the stator 522 located below the discharge port 51Bb is immersed in the coolant stored in the oil reservoir 57, and is always cooled by the coolant in the oil reservoir 57. As a result, the cooling liquid comes into contact with the radially outer peripheral surface 522c of the stator 522 over almost the entire region. For this reason, the cooling efficiency of the stator 522 can be increased, and the specific output of the electric motor 50 is improved.

  In the electric motor (rotating electric machine) of the third embodiment, the main load received by the motor case 51 when the rotor 521 rotates is a driving torque reaction force generated between the rotor 521 and the stator 522. This driving torque reaction force becomes a stator reaction force acting in the circumferential direction of the stator 522 (indicated by an arrow α in FIG. 11).

On the other hand, at the portion where the upper support projection 522e or the lower support projection 522f of the stator 522 is in contact with the case portion 511, a component force acts on the case portion 511 in accordance with the contact angle between the support projection portions 522e and 522f and the groove portion 515. 11 (indicated by an arrow β in FIG. 11. Although the upper support protrusion 522e is shown in FIG. 11, the same component force acts on each of the lower support protrusions 522f). This component force hardly acts at the top when each of the supporting protrusions 522e and 522f has an arc shape with a semicircular cross section.
Therefore, even if the arc-shaped top portion is deleted, there is no functional inconvenience for supporting the stator reaction force.

  Further, for example, when the stator 522 is press-fitted into the case portion 511 of the motor case 51, the support protrusions 522 e and 522 f have the same semicircular arc shape as the groove portion 515, and the entire circumferential surface is the groove portion 515. In the case where it is in contact with stress, stress concentration occurs at the arcuate apex (location indicated by γ in FIG. 11). Therefore, it can be considered that the case strength of the motor case 51 is harmed.

  On the other hand, when the top 522k of each of the support protrusions 522e and 522f is a flat surface and a gap K is provided between the top 522k and the groove 515, when the stator 522 is press-fitted into the motor case 51 and fixed, Stress concentration generated in the groove 515 is alleviated. Thereby, the effect of relatively improving the case strength can also be obtained.

  In addition, by making the top part 522k of each support protrusion part 522e, 522f into a flat surface, the outermost periphery diameter of the stator 522 becomes smaller than the support protrusion part which made the top part circular shape shown in Example 1 or Example 2. . For this reason, the material cost of the stator 522 can be saved as compared with the case where the top portion has an arc shape.

Next, the effect will be described.
In the rotating electrical machine of Embodiment 3, the following effects can be obtained.

(6) A circulation pump (oil pump) 58 for circulating the coolant in the motor case 51 is provided,
The motor case 51 has a cooling liquid reservoir (oil reservoir) 57 at a lower portion that allows a part of the stator 522 to be immersed in the cooling liquid.
The circulation pump 58 is configured to circulate the coolant from the coolant reservoir 57 toward the coolant supply unit 51A.
For this reason, the cooling liquid contacts the stator 522 over almost the entire region of the radial outer peripheral surface 522c of the stator body 522a, and the cooling efficiency of the stator 522 can be increased.

(7) In the upper support protrusion 522e and the lower support protrusion 522f, the top 522k facing the inner peripheral surface 513b of the motor case 51 is a flat surface, and the top 522k and the motor case 51 are flat. A gap K is provided between the groove portion 515 and the inner peripheral surface 513b.
For this reason, stress concentration generated in the groove portion 515 of the motor case 51 can be relaxed while ensuring a support function for the motor case 51.

  The fourth embodiment is an example in which an elastic seal member is interposed between the axial end surface of the stator and the motor case.

First, the configuration will be described.
FIG. 12 is a longitudinal sectional view showing an in-wheel motor unit to which the electric motor (rotating electric machine) of the fourth embodiment is applied. FIG. 13 is a cross-sectional view illustrating a stator and a seal member according to the fourth embodiment. In addition, about the structure similar to the said Example 1, the code | symbol same as Example 1 is attached | subjected and description is abbreviate | omitted.

  In the electric motor (rotating electric machine) 60 of the fourth embodiment, when the stator 622 is sandwiched between the case portion 611 and the cover portion 612 of the motor case 61, the cover portion 612 and one axial end surface 622d of the stator body 622a A seal member 67 having elasticity and water resistance is provided between them.

The seal member 67 is made of, for example, a high heat-resistant rubber material or a high heat-resistant resin material made of polyurethane or silicone material, and extends from the axial end portion of the upper support protrusion 622e to the discharge port 61Bb of the coolant discharge portion 61B. Provided immediately before the corresponding position.
In other words, here, the pair of coolant discharge portions 61B is provided at positions that are symmetrical in the circumferential direction with the bottom of the stator 622 as the center. The range in which the seal member 67 is provided passes from the position directly above the position corresponding to one of the discharge ports 61Bb of the pair of coolant discharge portions 61B through the axial end of the upper support protrusion 622e to the other discharge port. It is between the position just above the position corresponding to 61Bb.

  The seal member 67 is previously attached and fixed to the axial end surface 622d of the stator 622 with an adhesive or the like, and then a mounting flange portion 612a provided at the peripheral portion of the cover portion 612 is bolted to the peripheral portion of the case portion 611. By fixing with B, the stator 622 and the cover portion 612 are held.

Next, the operation will be described.
FIG. 14 is an explanatory diagram for explaining a dimensional relationship when the stator is built in the motor case.

  14, when the stator 722 is fixed in the motor case 71 configured by the case portion 711 and the cover portion 712, the stator main body of the stator 722 is fixed to each of the case portion 711 and the cover portion 712. The stator 722 is sandwiched between the case portion 711 and the cover portion 712 in a state where the axial end surface 722d of the 722a is in contact. Then, the mounting flange portion 712 a formed on the peripheral portion of the cover portion 712 is bolted to the peripheral portion of the case portion 711, and the stator 722 is fixed to the motor case 71.

On the other hand, parts generally have manufacturing tolerances, and dimensional variations occur between the parts. Therefore, also in the electric motor D, in order to avoid a problem that the mounting flange portion 712a is lifted in the axial direction, that is, a problem that a gap is generated between the mounting flange portion 712a and the case portion 711, the dimension of the following formula (1) Have a relationship.
Case part processing dimension L1> stator axial direction dimension L2 + cover part inlay dimension L3 (1)

  By making the dimensional relationship satisfying the expression (1), the mounting flange portion 712a can be prevented from being lifted. However, when the manufacturing tolerance of the axial dimension L2 of the stator 722 and the manufacturing tolerance of the inlay dimension L3 of the cover portion 712 are the minimum tolerance, and the manufacturing tolerance of the processing dimension L1 of the case portion 711 is the maximum tolerance, the stator 722 There may be a gap between the axial end surface 722d of the case 711 and the case portion 711 and the cover portion 712. In this case, problems such as axial shakiness of the stator 722 and leakage of coolant from the annular gap 76 may occur.

  On the other hand, in the electric motor (rotating electric machine) 60 according to the fourth embodiment, an elastic seal member 67 is provided between the cover portion 612 and one axial end surface 622d of the stator main body 622a.

Therefore, regardless of the manufacturing tolerance of each part, the dimensional error generated between the case portion processing dimension L1, the stator axial direction dimension L2, and the cover part inlay dimension L3 can be absorbed by the elastic deformation of the seal member 67, and the ring The coolant can be prevented from leaking from the gap 66.
Thereby, it is possible to efficiently use the cooling liquid for cooling the stator without leaking the cooling liquid from the annular gap 66 while suppressing the rattling of the stator 622.

  Further, the elastic deformation of the seal member 67 can prevent the stator 622 from rattling in the axial direction, and the stator 622 cannot move freely in the axial direction. Therefore, it is possible to prevent problems such as generation of abnormal noise accompanying the driving of the rotor 621 and output reduction caused by the positional displacement of the rotor 621 and the stator 622 in the axial direction.

Next, the effect will be described.
In the rotating electrical machine of the fourth embodiment, the following effects can be obtained.

(8) An elastic seal member 67 is provided between the motor case 61 and the axial end surface 622d of the stator 622.
For this reason, it is possible to absorb a dimensional error generated between the motor case 61 and the stator 622 due to the elastic deformation of the seal member 67 and prevent the coolant from leaking out from the annular gap portion 66.

  As mentioned above, although the rotary electric machine of this invention was demonstrated based on Example 1-Example 4, it is not restricted to these Examples about a concrete structure, It concerns on each claim of a claim Design changes and additions are allowed without departing from the scope of the invention.

  In the first embodiment, by forming one upper support protrusion 222e and a pair of lower support protrusions 222f, there are three radial contact points between the motor case 21 and the stator 222. However, the present invention is not limited to this, and the support protrusions 222e and 222f extend in the axial direction and are three-dimensionally formed in the axial direction.

  In the first embodiment, the supply path 21Aa of the coolant supply part 21A passes through the case part 211 and the cover part 212. However, the present invention is not limited to this. For example, the supply path 21Aa passes through only the case portion 211, and the cooling liquid is directly supplied to the annular gap portion 26 from the outside of the case portion 211, or the supply path 21Aa passes only through the cover portion 212, The cooling liquid may be directly supplied to the annular gap portion 26 from outside 212. At this time, the supply port 21Ab is formed in the cover portion 212.

  Furthermore, in the first embodiment, a pair of the coolant supply unit 21A and the coolant discharge unit 21B are provided. Further, the same number may not be provided across the vertical direction L1.

  And in Example 1, although the axial direction dimension of the wide protrusion part 222g is the same magnitude | size as the axial direction dimension of the stator main body 222a, it is not restricted to this. The wide protrusion 222g may be shorter than the axial dimension of the stator body 222a, or the wide protrusion 222g may be divided in the axial direction.

  Moreover, in the said Example 2, although the small projection part 422j is provided in each of the circumferential direction upper side position and the circumferential direction lower side position of the wide projection part 422g, it is not restricted to this. If the wide protrusion 422g is provided at either the circumferential upper position or the circumferential lower position, the flow rate of the coolant flowing through the annular gap 46 can be finely adjusted.

  Further, in the fourth embodiment, the seal member 67 passes from the position directly above the position corresponding to one of the discharge ports 61Bb of the pair of coolant discharge portions 61B through the axial end of the upper support protrusion 622e, and the other It is provided between the position corresponding to the outlet 61Bb and the position immediately above it. However, for example, when the coolant is discharged directly from the annular gap 66 to the outside of the motor case 61, the seal member 67 may be provided over the entire circumference of the stator 622.

  In the first to fourth embodiments, the rotating electric machine (electric motor) of the present invention is applied to the in-wheel motor unit MU. However, the present invention is not limited to this. The rotating electricity of the present invention can be applied as a drive source for an electric vehicle such as a hybrid vehicle or an electric vehicle.

20 Electric motor (rotary electric machine)
21 Motor case 211 Case portion 212 Cover portion 213a Outer peripheral surface 213b Inner peripheral surface 215 Groove portion 21A Coolant supply portion 21B Coolant discharge portion 22 Motor portion 221 Rotor 222 Stator 222a Stator main body 222c Radial outer peripheral surface 222d Axial end surface 222e Upper support Projection 222f Lower support projection 222g Wide projection 222h Upper surface 222i Narrow gap 23 Reduction gear 24 Input shaft (rotor shaft)
25 Output shaft 26 Ring gap

Claims (8)

A motor case that supports the rotor shaft in a substantially horizontal state;
A rotor rotatable integrally with the rotor shaft;
An annular stator supported by the motor case and disposed on a radially outer periphery of the rotor;
A coolant supply unit that is formed in an upper portion of the motor case and supplies a coolant for cooling the stator;
An annular gap provided between the inner peripheral surface of the motor case and the outer peripheral surface in the radial direction of the stator, and in communication with the cooling liquid supply unit, the cooling liquid flowing down by its own weight;
A wide protrusion that protrudes from the outer circumferential surface of the stator in the radial direction, has a predetermined dimension in the circumferential direction with respect to a substantially central part in the vertical direction, and extends in the axial direction to narrow the gap dimension of the annular gap part; ,
A rotating electrical machine comprising: In the rotating electrical machine according to claim 1,
The stator is formed to protrude at the top of the radially outer peripheral surface, and has an upper support protrusion that contacts the inner peripheral surface of the motor case,
A plurality of the cooling liquid supply units are provided at positions that are symmetrical in the circumferential direction around the upper support protrusion. In the rotating electrical machine according to claim 1 or 2,
The stator is provided at a circumferential upper position or a circumferential lower position of the wide projection, and has a plurality of small projections having a circumferential dimension and an axial dimension smaller than the wide projection. Rotating electric machine. In the rotating electrical machine according to any one of claims 1 to 3,
A circulation pump for circulating the coolant in the motor case;
The motor case has a cooling liquid reservoir at a lower part that allows a part of the stator to be immersed in the cooling liquid.
The rotating electric machine circulates the coolant from the coolant reservoir to the coolant supply unit. In the rotating electrical machine according to any one of claims 1 to 4,
An electrical rotating machine, wherein an elastic seal member is provided between the motor case and the axial outer peripheral surface of the stator. In the rotating electrical machine according to any one of claims 1 to 5,
The stator is formed so as to protrude from the outermost surface of the radially outer peripheral surface, and an upper support protrusion that contacts the inner peripheral surface of the motor case.
A rotating electrical machine comprising: a pair of lower support protrusions that are formed so as to protrude symmetrically in the circumferential direction around the bottom of the radially outer peripheral surface and are in contact with the inner peripheral surface of the motor case. In the rotating electrical machine according to claim 6,
The motor case is disposed on the vehicle inner side of the wheel that supports the wheel, and is held swingably on the vehicle body via a suspension mechanism.
A rotating electrical machine characterized in that a suspension mounting portion for attaching the suspension mechanism is provided on the outer peripheral surface of the motor case in accordance with the position of the upper support protrusion or the lower support protrusion. In the rotary electric machine according to claim 6 or 7,
At least one of the upper support protrusion or the lower support protrusion has a top portion facing the inner peripheral surface of the motor case as a flat surface, and the top portion formed as a flat surface and the inner peripheral surface of the motor case A rotating electric machine characterized by providing a gap therebetween.