Electric rotary machine

An electric rotary machine includes a rotor and a stator disposed radially outward of the rotor. The rotor includes a rotor shaft, a rotor core, a plurality of magnetic pole portions, a first end plate, and a second end plate. The first end plate includes a refrigerant discharge hole, a first groove portion communicating with a refrigerant flow path and communicating with a first refrigerant flow path hole, and a second groove portion communicating with the first groove portion and communicating with a refrigerant discharge hole of the first end plate. The second end plate includes a refrigerant discharge hole, and a third groove portion communicating with the first refrigerant flow path hole and communicating with a refrigerant discharge hole of the second end plate.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority from Japanese Patent Application No. 2018-197885 filed on Oct. 19, 2018, the entire contents of which are incorporated herein by reference.

FIELD

The present invention relates to an electric rotary machine.

BACKGROUND

With the recent increase in the size of electric rotary machines, the deterioration in the performance of electric rotary machines due to heat generation of magnetic pole portions cannot be neglected and methods for efficiently cooling the magnetic pole portions are being sought. JP-A-2018-33265 discloses a rotor of an electric rotary machine including a rotor core and a pair of end surface plates disposed on both end surfaces of the rotor core, where refrigerant supplied from a rotor shaft is introduced into the inside of the rotor core from an annular groove formed in one end surface plate and is discharged from the other end surface plate through a through hole formed inside the rotor core. This allows the rotor core to be cooled internally.

In the electric rotary machine, since a coil of a stator also generates heat, it is necessary to simultaneously cool the coil of the stator. However, regarding the rotor of the electric rotary machine described in JP-A-2018-33265, any method for cooling the coil of the stator is not described.

SUMMARY

The invention provides an electric rotary machine capable of cooling magnetic pole portions of a rotor from the inside of a rotor core and also cooling a coil of a stator using refrigerant discharged from the rotor core.

The invention provides an electric rotary machine which includes a rotor and a stator disposed radially outward of the rotor, wherein

the rotor includes:a rotor shaft having a refrigerant flow path provided inside thereof;a rotor core having a rotor shaft hole through which the rotor shaft passes, a plurality of magnet insertion holes provided along a circumferential direction, and a first refrigerant flow path hole axially passing through the rotor core;a plurality of magnetic pole portions configured by magnets inserted into the magnet insertion holes;a first end plate disposed at a first axial end side of the rotor core; anda second end plate disposed on a second axial end side of the rotor core opposite to the first axial end side, and

the stator includes:a first coil end located radially outward of the first end plate; anda second coil end located radially outward of the second end plate,

the first end plate includes:a refrigerant discharge hole;a first groove portion communicating with the refrigerant flow path and communicating with the first refrigerant flow path hole; anda second groove portion communicating with the first groove portion and communicating with the refrigerant discharge hole of the first end plate, and

the second end plate includes:a refrigerant discharge hole; anda third groove portion communicating with the first refrigerant flow path hole and communicating with the refrigerant discharge hole of the second end plate.

According to the invention, magnetic pole portions of a rotor can be internally cooled by refrigerant passing through a first refrigerant flow path hole, and a first coil end and a second coil end on both sides of the stator can be cooled by refrigerant discharged from refrigerant discharge holes of a first end plate and a second end plate.

DETAILED DESCRIPTION

Hereinafter, an electric rotary machine of each embodiment of the invention will be described based on the attached drawings.

As illustrated inFIG. 1, an electric rotary machine50is a so-called inner-rotor-type electric rotary machine including a rotor51and a stator52disposed to face an outer diameter side of the rotor51with a slight gap therebetween.

First Embodiment

As illustrated inFIGS. 2 to 5, the rotor51of the first embodiment includes a rotor shaft10, a rotor core20axially supported on the rotor shaft10, and a plurality of magnetic pole portions30, a first end plate40adisposed on one axial end side of the rotor core20, and a second end plate40bdisposed on the other axial end side of the rotor core20.

In the rotor shaft10, a refrigerant flow path11in which the refrigerant flows is formed. The refrigerant flow path11extends in an axial direction inside the rotor shaft10and the refrigerant can be supplied from the outside. As the refrigerant, Automatic Transmission Fluid (ATF) is used, for example. The refrigerant flow path11is connected to a circulation path formed in a housing (not illustrated) accommodating the electric rotary machine50.

The rotor core20is formed, for example, by laminating a plurality of electromagnetic steel plates formed by press processing in an axial direction and joining them with caulking, adhesion, or the like.

The rotor core20includes a rotor shaft hole21through which the rotor shaft10is inserted, a cooling portion22provided outside the rotor shaft hole21in the radial direction, and an electromagnetic portion23provided outside the cooling portion22in the radial direction.

The electromagnetic portion23is disposed on an outer periphery of the rotor core20and faces the stator52. In the electromagnetic portion23, a plurality of magnetic pole portions30are formed at equal intervals along a circumferential direction. Each magnetic pole portion30is constituted of three magnets31inserted into three magnet insertion holes24arranged in a substantial arc shape convex inward in a radial direction. The magnet31is, for example, a permanent magnet such as a neodymium magnet. The magnetic pole portion30may be constituted of two magnets arranged in two magnet insertion holes arranged in a substantially V-shape opening outward in the radial direction or constituted of one flat plate magnet or circular arc magnet.

The cooling portion22includes first refrigerant flow path holes25and second refrigerant flow path holes26alternately arranged along the circumferential direction.

The first refrigerant flow path hole25is located on a d-axis connecting the center of each magnetic pole portion30and the center CL of the rotor51. The second refrigerant flow path holes26are located on q-axes passing through one circumferential end portion and the other circumferential end portion of each magnetic pole portion30and the center CL of the rotor51.

The first refrigerant flow path hole25has a substantially pentagonal shape with a radially inward protruding apex portion and has a radial-inner-side apex portion25dwhich protrudes radially inward. The second refrigerant flow path hole26has a substantially rectangular shape which is convex on both sides in the circumferential direction and both sides in the radial direction and has a radial-inner-side apex portion26dwhich protrudes radially inward. The radial-inner-side apex portion26dof the second refrigerant flow path hole26is located further on an outer side than the radial-inner-side apex portion25dof the first refrigerant flow path hole25in the radial direction. That is, in the cooling portion22of the rotor core20, the radial-inner-side apex portion25dof the first refrigerant flow path hole25is located at a radially innermost position.

The first end plate40ais disposed to face an end surface of the rotor core20, which is the end surface on one end side in an axial direction, as illustrated inFIGS. 2, 4, and 5. An insertion hole41for inserting the rotor shaft10is formed at the center of the first end plate40a. In addition, on the radially outer side than the insertion hole41, a plurality of refrigerant discharge holes42are formed at equal intervals in the circumferential direction so as to overlap with the second refrigerant flow path holes26formed in the rotor core20.

Further, on an inner side surface of the first end plate40a, formed are a refrigerant introduction groove43of an annular shape which communicates with a refrigerant supply path12formed in the rotor shaft10at a radial-inner-side corner portion of the insertion hole41, a first groove portion44of an annular shape which communicates with the refrigerant introduction groove43and communicates with the first refrigerant flow path hole25of the rotor core20, and a second groove portion45which communicates with the first groove portion44and communicates with a refrigerant discharge hole42of the first end plate40a.

The first groove portion44is continuous from the refrigerant introduction groove43and is an annular concave groove having a radius D1larger than the radial-inner-side apex portion25dof the first refrigerant flow path hole25from the center CL of the rotor51and smaller than the radial-inner-side apex portion26dof the second refrigerant flow path hole26. Therefore, the refrigerant flowing through the refrigerant flow path11is introduced from the refrigerant introduction groove43to the first groove portion44as indicated by T0in the drawing, and then the refrigerant is supplied from the first groove portion44to the first refrigerant flow path hole25of the rotor core20as indicated by T2in the drawing. The refrigerant supplied to the first refrigerant flow path hole25cools the magnet31disposed in each magnetic pole portion30by flowing the first refrigerant flow path hole25from one side to the other side in the axial direction.

The second groove portion45is a concave groove extending linearly from the outer periphery portion of the first groove portion44in the radial direction. The second groove portions45are provided with the same number as that of the refrigerant discharge holes42of the first end plate40aand the second groove portions45are respectively connected to the refrigerant discharge holes42. Therefore, a part of the refrigerant introduced from the refrigerant introduction groove43to the first groove portion44is discharged from the refrigerant discharge hole42of the first end plate40athrough the second groove portion45as indicated by T1in the drawing.

The second end plate40bis disposed to face an end surface of the rotor core20, which is the end surface on the other end side in the axial direction. The insertion hole41through which the rotor shaft10is inserted is formed at the center of the second end plate40b, and further, in a portion radially outer side than the insertion hole41, a plurality of refrigerant discharge holes42are formed at equal intervals in the circumferential direction so as to overlap with the second refrigerant flow path holes26formed in the rotor core20.

In addition, a third groove portion46is formed on the inner surface of the second end plate40bso as to communicate with the first refrigerant flow path hole25of the rotor core20and to communicate with the refrigerant discharge hole42of the second end plate40b.

The third groove portion46is continuous from the insertion hole41and is an annular concave groove having a radius D2larger than the refrigerant discharge hole42of the second end plate40bfrom the center CL of the rotor51. Therefore, the refrigerant supplied from the first refrigerant flow path hole25is discharged from the refrigerant discharge hole42of the second end plate40bthrough the third groove portion46as indicated by T3in the drawing.

Although the refrigerant discharge holes42of the first end plate40aand the second end plate40bhave a substantially triangular shape with an apex radially outward, the shape of the refrigerant discharge hole42can be changed as appropriate.

The stator52includes a stator core91, and coils92wound around a plurality of slots formed in the stator core91. The coil92includes a first coil end98awhich protrudes in the axial direction from one end surface91aside of the stator core91and a second coil end98bwhich protrudes in the axial direction from the other end surface91bside of the stator core91. The first coil end98ais located radially outward of the first end plate40aand the second coil end98bis located radially outward of the second end plate40b. Therefore, the refrigerant discharged from the refrigerant discharge hole42of the first coil end98ais supplied to the first coil end98aand the refrigerant discharged from the refrigerant discharge hole42of the second end plate40bis supplied to the second coil end98b.

Next, the cooling action of the electric rotary machine50will be described.

In the electric rotary machine50of the embodiment, the refrigerant pressure-fed by a refrigerant pump (not illustrated) is supplied to the rotor shaft10via the circulation path. The refrigerant supplied to the refrigerant flow path11is supplied to a refrigerant supply path12radially passing through the rotor shaft10.

The refrigerant of the refrigerant supply path12passes through the refrigerant introduction groove43and the first groove portion44of the first end plate40aby the centrifugal force acting on the refrigerant as indicated by T0in the drawing and is supplied to the first refrigerant flow path hole25of the rotor core20as indicated by T2in the drawing, and then the refrigerant flows through the first refrigerant flow path hole25to internally cool the rotor core20. Since the first refrigerant flow path hole25is disposed in the vicinity of the magnetic pole portion30, the magnet31with the largest amount of heat generation can be cooled effectively.

The refrigerant supplied to the first groove portion44is further discharged from the refrigerant discharge hole42of the first end plate40athrough the second groove portion45from the first groove portion44as indicated by T1in the drawing and supplied to the first coil end98a. In addition, the refrigerant flowing through the first refrigerant flow path hole25is discharged from the refrigerant discharge hole42of the second end plate40bthrough the third groove portion46as indicated by T3in the drawing and supplied to the second coil end98b. As a result, the refrigerant discharged from the rotor core20can be used to cool the coil92of the stator52, particularly the first coil end98aand the second coil end98bon both sides of the stator core91.

According to the embodiment, the refrigerant supplied from the refrigerant supply path12of the rotor shaft10can be distributed into two paths, that is, a path where the refrigerant is discharged from the refrigerant discharge hole42of the first end plate40athrough the first groove portion44and the second groove portion45of the first end plate40aand a path where the refrigerant is discharged from the refrigerant discharge hole42of the second end plate40bthrough the first groove portion44of the first end plate40a, the first refrigerant flow path hole25, and the third groove portion46. Therefore, the first coil end98aand the second coil end98bon both sides of the stator52can be cooled. In addition, the magnetic pole portion30of the rotor51can be internally cooled by the refrigerant passing through the first refrigerant flow path hole25.

Second Embodiment

Next, an electric rotary machine50according to a second embodiment will be described with reference toFIGS. 6 to 9. Since the electric rotary machine50of the second embodiment differs from the electric rotary machine50of the first embodiment only in the size of the refrigerant discharge hole42of the first end plate40a, the same reference numerals are given to the same configurations and the descriptions thereof are omitted.

In the electric rotary machine50of the second embodiment, as illustrated inFIG. 6, the refrigerant discharge hole42of the first end plate40ais smaller than the second refrigerant flow path hole26when viewed from the axial direction. Thus, by making the refrigerant discharge hole42smaller than the second refrigerant flow path hole26, a part of the refrigerant passing through second groove portion45is introduced to the second refrigerant flow path hole26as indicated by T4in the drawing. Further, as illustrated inFIGS. 7 and 9, since the third groove portion46of the second end plate40balso communicates with the second refrigerant flow path hole26, the refrigerant supplied from the second refrigerant flow path hole26is discharged from the refrigerant discharge hole42of the second end plate40bthrough the third groove portion46.

Therefore, according to the electric rotary machine50of the embodiment, in addition to the two paths described in the first embodiment, the refrigerant supplied from the refrigerant supply path12of the rotor shaft10flows through the first groove portion44and the second groove portion45of the first end plate40ainto the second refrigerant flow path hole26and is discharged from the refrigerant discharge hole42of the second end plate40bthrough the third groove portion46. Therefore, the refrigerant supplied from the refrigerant supply path12of the rotor shaft10can be distributed into three paths.

In particular, since an outer-diameter-side apex portion26eof the second refrigerant flow path hole26is located radially outward of an innermost diameter portion32of the magnetic pole portion30, a refrigerant flow path can be formed in the vicinity of the circumferential end portion of the magnetic pole portion30and the cooling performance of the rotor51is improved.

In the embodiment described above, modifications, improvements, and the like can be made as appropriate. For example, in the first embodiment, the second refrigerant flow path hole26may not be provided.

At least the following matters are described in the specification. In addition, although the components or the likes corresponding to those in the embodiments described above are shown in parenthesis, it is not limited thereto.

(1) An electric rotary machine (electric rotary machine50) which includes a rotor (rotor51) and a stator (stator52) disposed radially outward of the rotor, wherein

the rotor includes:a rotor shaft (rotor shaft10) having a refrigerant flow path (refrigerant flow path11) provided inside thereof;a rotor core (rotor core20) having a rotor shaft hole (rotor shaft hole21) through which the rotor shaft passes, a plurality of magnet insertion holes (magnet insertion holes24) provided along a circumferential direction, and a first refrigerant flow path hole (first refrigerant flow path hole25) axially passing through the rotor core;a plurality of magnetic pole portions (magnetic pole portions30) configured by magnets (magnets31) inserted into the magnet insertion holes;a first end plate (first end plate40a) disposed at a first axial end side of the rotor core; anda second end plate (second end plate40b) disposed on a second axial end side of the rotor core opposite to the first axial end side,

the stator includes:a first coil end (first coil end98a) located radially outward of the first end plate; anda second coil end (second coil end98b) located radially outward of the second end plate,

the first end plate includes:a refrigerant discharge hole (refrigerant discharge hole42);a first groove portion (first groove portion44) communicating with the refrigerant flow path and communicating with the first refrigerant flow path hole; anda second groove portion (second groove portion45) communicating with the first groove portion and communicating with the refrigerant discharge hole of the first end plate, and

the second end plate includes:a refrigerant discharge hole (refrigerant discharge hole42); anda third groove portion (third groove portion46) communicating with the first refrigerant flow path hole and communicating with the refrigerant discharge hole of the second end plate.

According to (1), since the first end plate includes the first groove portion communicating with the refrigerant flow path of the rotor shaft and communicating with the first refrigerant flow path hole, the refrigerant supplied from the refrigerant flow path can be supplied to the first refrigerant flow path hole of the rotor core and the magnetic pole portions of the rotor can be internally cooled. Also, since the second groove portion of the first end plate communicates with the refrigerant discharge hole of the first end plate, a part of the refrigerant supplied to the first groove portion can be discharged from the refrigerant discharge hole of the first end plate through the second groove portion. This makes it possible to cool the first coil end on one end side of the stator.

Furthermore, the third groove portion of the second end plate communicates with the first refrigerant flow path hole and also communicates with the refrigerant discharge hole of the second end plate, the refrigerant supplied to the third groove portion through the first refrigerant flow path hole can be discharged from the refrigerant discharge hole. Therefore, it is possible to cool the second coil end on the other end side of the stator.

Therefore, the refrigerant supplied from the refrigerant flow path of the rotor shaft can be distributed into two paths and the first coil end and the second coil end on both sides of the stator can be cooled by the refrigerant discharged from the refrigerant discharge hole of the first end plate through the first groove portion and the second groove portion of the first end plate, and the refrigerant discharged from the refrigerant discharge hole of the second end plate through the first groove portion of the first end plate, the first refrigerant flow path hole, and the third groove portion. In addition, the magnetic pole portions of the rotor can be internally cooled by the refrigerant passing through the first refrigerant flow path hole.

(2) The electric rotary machine according to (1), wherein

each of the first end plate and the second end plate is provided with a plurality of the refrigerant discharge holes.

According to (2), since the first end plate and the second end plate are respectively provided with a plurality of the refrigerant discharge holes, more refrigerant can be supplied to the first coil end and the second coil end.

(3) The electric rotary machine according to (1) or (2), wherein

each of the first end plate and the second end plate is provided with a plurality of the refrigerant discharge holes at an equal interval in the circumferential direction.

According to (3), since the plurality of refrigerant discharge holes are provided at an equal interval in the circumferential direction in the first end plate and the second end plate, the refrigerant can be supplied to the first coil end and the second coil end without bias.

(4) The electric rotary machine according to (3), wherein

a plurality of the second groove portions are provided to correspond to the plurality of refrigerant discharge holes.

According to (4), since the plurality of second groove portions are provided to correspond to the plurality of refrigerant discharge holes, more refrigerant can be supplied to the first coil end and the second coil end evenly along the circumferential direction.

(5) The electric rotary machine according to any one of (1) to (4), wherein

the rotor core further includes a second refrigerant flow path hole (second refrigerant flow path hole26) which penetrates the rotor core in an axial direction and which is disposed so as to overlap with the refrigerant discharge holes of the first end plate and the second end plate,

the third groove portion communicates with the first refrigerant flow path hole, the second refrigerant flow path hole, and the refrigerant discharge hole of the second end plate, and

the second refrigerant flow path hole is larger than the refrigerant discharge hole of the first end plate as viewed from the axial direction.

According to (5), a part of the refrigerant which flows through the first groove portion and the second groove portion of the first end plate to the refrigerant discharge hole of the first end plate is discharged from the refrigerant discharge hole of the first end plate through the first groove portion and the second groove portion of the first end plate and the remaining refrigerant flows into the second refrigerant flow path hole and is discharged from the refrigerant discharge hole of the second end plate through the third groove portion. Therefore, the refrigerant supplied from the refrigerant flow path of the rotor shaft can be distributed into three paths.

(6) The electric rotary machine according to (5), wherein

an outer-diameter-side end portion (outer-diameter-side apex portion26e) of the second refrigerant flow path hole is located further radially outward than an innermost diameter portion (innermost diameter portion32) of the magnetic pole portions.

According to (6), it is possible to effectively cool the magnet, which is the heating element, by the refrigerant passing through the second refrigerant flow path hole.

(7) The electric rotary machine according to (5) or (6), wherein

a plurality of the first refrigerant flow path holes are provided at a predetermined interval along the circumferential direction,

a plurality of the second refrigerant flow path holes are provided at a predetermined interval along the circumferential direction,

the first groove portion is an annular groove formed on an inner surface of the first end plate, and

the second groove portion is a linear groove extending radially from the annular groove toward each of the second refrigerant flow path holes.

According to (7), a plurality of first refrigerant flow path holes and second refrigerant flow path holes are respectively provided at predetermined intervals along the circumferential direction, and the first groove portion is an annular groove, and further the second groove portion is a straight groove extending radially from the annular groove towards each second refrigerant flow path hole. As a result, the refrigerant can be supplied with good balance.