Patent Description:
Hitherto, as a stator cooling structure of a rotating electrical machine, there has been known one that is configured to cool a coil end by dropping refrigerant from above the coil end, as disclosed in Patent Publication <NUM>. For example, in case that the coil is formed by concentrated winding, coils that are adjacent to each other in the circumferential direction are spaced away from each other. Therefore, even if refrigerant is dropped from above coil end, there has been a problem in which it is difficult to propagate refrigerant to adjacent coil, thereby making an efficient coil end cooling impossible.

Against such problem, the following Patent Publication <NUM> discloses a cooling device of a vehicle power transmission apparatus in which an outer peripheral annular oil tube and an inner peripheral annular oil tube are provided, these are respectively formed with a plurality of discharging holes for discharging cooling oil toward coil ends, and cooling oil is supplied to the annular oil tubes, thereby uniformly supplying cooling oil in the circumferential direction of the coil ends.

The following Patent Publication <NUM> discloses an oil cooling structure of a motor, in which an oil passage cover that covers an opening surface of a circumferential oil passage extending along the circumferential direction of a motor is formed with a plurality of discharging holes at predetermined intervals, and oil is supplied from these discharging holes towards the clearances between adjacent coils, thereby supplying oil to all of the coils.

Furthermore, each of the following Patent Publications <NUM> and <NUM> discloses a cooling structure of a rotating electrical machine, in which a side cover for protecting a rotor and a stator is formed with a discharging hole for supplying refrigerant via a passage, and refrigerant is discharged from this discharging hole, thereby improving coil cooling efficiency.

Furthermore, the following Patent Publication <NUM> discloses a cooling structure of a rotating electrical machine, in which there is provided a refrigerant passage tube that extends in the circumferential direction along an outer end surface in the axial direction of the rotating electrical machine, and a plurality of openings that communicate with the inside of the tube are formed at positions that are opposed to the outer end surface in the axial direction of the rotating electrical machine and are on an outer peripheral surface of this refrigerant passage tube, thereby efficiently cooling the rotating electrical machine.

A cooling structure according to the preamble of claim <NUM> is known from Patent Publication <NUM>.

It is an object of the present invention to provide a cooling structure of a stator of a rotating electrical machine that is capable of surely cooling a stator coil end of each unit coil and simultaneously cooling and lubricating a bearing that supports a rotation shaft of said rotating electrical machine.

This object is satisfied by a cooling structure according to claim <NUM>. Further developments of the invention are defined in the dependent claims.

A cooling structure of a stator of a rotating electrical machine according to the present invention is capable of surely cooling a stator coil end of each unit coil of a rotating electrical machine, and simultaneously cooling and lubricating a bearing that supports a rotation shaft of said rotating electrical machine.

In the following, a cooling structure of a stator of a rotating electrical machine according to one embodiment of the present invention is explained by using <FIG>.

As shown in <FIG>, in the present embodiment, the rotating electrical machine is equipped with a rotation shaft <NUM> that is rotatably supported in a casing <NUM> through bearings <NUM>, a rotor (not shown in the drawings) that is fixed to an outer peripheral portion of the rotation shaft <NUM>, and a stator <NUM> that is disposed to be opposed to the outer peripheral portion of the rotor through an air gap and is fixed to the casing <NUM>.

The casing <NUM> is constituted to include a generally cylindrical frame <NUM>, and a non-direct-coupling-side bracket <NUM> and a direct-coupling-side bracket <NUM> that are mounted on opening portions of this frame <NUM>.

The stator <NUM> is equipped with stator cores <NUM> and stator coils wound around the stator cores <NUM>. In the following, parts that project from the stator core <NUM> of this stator coil <NUM> toward axial both sides (non-direct-coupling side and direct-coupling side) are referred to as stator coil ends 42A, 42B.

The stator coil <NUM> is formed by concentrated winding. An end portion (exit wire) of a wire that forms each unit coil 42a (see <FIG>) is disposed on the non-direct-coupling side. The exit wire is connected by a bus bar <NUM> per each phase.

Furthermore, as shown in <FIG>, this rotating electrical machine is equipped with a refrigerant supplying body for supplying a refrigerant (cooling oil) to stator coil ends 42A, 42B, etc. The refrigerant supplying body is constituted to include a refrigerant introducing portion <NUM> that extends along the axial direction, and oil guides <NUM>, <NUM> that are connected to both sides in the axial direction of the refrigerant introducing portion <NUM>.

The refrigerant introducing portion <NUM> is a hollow cylindrical body and is fixed, for example, to the frame <NUM>. In the present embodiment, the refrigerant introducing portion <NUM> is formed into an oval shape in sectional view. This refrigerant introducing portion <NUM> has an inflow portion <NUM> for introducing refrigerant that is supplied from the outside of the casing <NUM>, refrigerant supply ports <NUM>, <NUM> that are respectively connected to the oil guides <NUM>, <NUM>, and a refrigerant supplying nozzle <NUM> for supplying refrigerant onto the stator cores <NUM>.

The oil guides <NUM>, <NUM> are made of an insulator (e.g., resin) having heat resistance and oil resistance and are respectively fixed, for example, to brackets <NUM>, <NUM>. The oil guides <NUM>, <NUM> are those each prepared by forming a tube with opened both ends into a generally arc shape, and the both ends extend generally straight toward the outside in the radial direction. In the following, arc parts of the oil guides <NUM>, <NUM> are referred to as arc portions <NUM>, <NUM>, and straight parts toward the outside in the radial direction are referred to as straight portions <NUM>, <NUM>. In the present embodiment, the arc portions <NUM>, <NUM> and the straight portions <NUM>, <NUM> constitute a refrigerant passage.

The arc portions <NUM>, <NUM> of these oil guides <NUM>, <NUM> are respectively disposed to be opposed to axial end portions of the stator coil ends 42A, 42B. Furthermore, tip ends (opening portions) of the straight portions <NUM>, <NUM> of the oil guides <NUM>, <NUM> are respectively connected to the refrigerant supply ports <NUM>, <NUM> of the refrigerant introducing portion <NUM>.

The oil guide <NUM> is provided with a refrigerant discharging portion <NUM> of the arc portion <NUM> that is formed at a position corresponding to the stator coil end 42A of each unit coil 42a, and refrigerant discharging portions (other refrigerant discharging portions) <NUM> of the straight portions <NUM> that are formed at positions opposed to an inner peripheral surface of the casing <NUM>.

In the present embodiment, the refrigerant discharging portion <NUM> of the oil guide <NUM> is a projection portion that extends from the arc portion <NUM> toward the stator coil end 42A side. That is, the refrigerant discharging portion <NUM> is constituted to eject refrigerant from a tip end of a projection that extends from the arc portion <NUM> toward the stator coil end 42A. As shown in <FIG>, the refrigerant discharging portion <NUM> is arranged such that its tip end is positioned on the stator coil end 42A side than the tip end of the exit wire and the tip end of the bus bar <NUM>.

Furthermore, the refrigerant discharging portion <NUM> of the oil guide <NUM> is a projection portion that extends from the straight portion <NUM> toward the inner peripheral surface side of the casing <NUM>. That is, the refrigerant discharging portion <NUM> is constituted to eject refrigerant from a tip end of a projection that extends from the straight portion <NUM> toward the inner peripheral surface of the casing <NUM>.

Furthermore, the oil guide <NUM> is provided with a refrigerant discharging portion <NUM> of the arc portion <NUM> that is formed at a position corresponding to the stator coil end 42B of each unit coil 42a, and refrigerant discharging portions (other refrigerant discharging portions) <NUM> of the straight portions <NUM> that are formed at positions opposed to an inner peripheral surface of the casing <NUM>.

In the present embodiment, a refrigerant discharging portion <NUM> of the oil guide <NUM> is an opened hole that is formed in the arc portion <NUM> and is constituted to directly eject refrigerant from the arc portion <NUM> toward the stator coil end 42B.

Furthermore, the refrigerant discharging portion <NUM> of the oil guide <NUM> is formed to project from the straight portion <NUM> toward inner peripheral surface side of the casing <NUM>. That is, the refrigerant discharging portion <NUM> is constituted to eject refrigerant from a tip end of a projection that extends from the straight portion <NUM> towards the inner peripheral surface of the casing <NUM>.

By a stator cooling structure of a rotating electrical machine according to the present embodiment structured as above, it is possible to surely supply refrigerant from the refrigerant discharging portion <NUM>, <NUM> of the oil guide <NUM>, <NUM> to the stator coil end 42A, 42B of each unit coil 42a. Therefore, it is possible to uniformly cool the stator coil ends 42A, 42B in the circumferential direction.

In particular, even in case that it is not possible to position the arc portion <NUM> of the oil guide <NUM> close to the non-direct-coupling-side stator coil ends 42A on which bus bars, etc. are disposed, the refrigerant discharging portion <NUM> is formed into a projection portion that extends towards the stator coil end 42A. With this, the refrigerant can reach the stator coil end 42A of each unit coil 42a. Therefore, it becomes possible to surely cool the stator coil end 42A.

Furthermore, the refrigerant discharging portion <NUM>, <NUM> is formed at a position of the straight portion <NUM>, <NUM> of the oil guide <NUM>, <NUM> that corresponds to the inner peripheral surface of the casing <NUM> to supply refrigerant toward the inner peripheral surface of the casing <NUM>. With this, it also becomes possible to conduct cooling and lubrication of the bearing <NUM>.

Furthermore, since the oil guide <NUM> is formed by an insulator, it is possible to extend the refrigerant discharging portion <NUM> of the oil guide <NUM> to the vicinity of the stator coil end 42A. With this, it becomes possible to surely supply refrigerant to the stator coil end 42A.

The present invention is not limited to the above-mentioned embodiment, but various modifications are possible to the extent of not deviating from the scope of the invention, which is defined by the independent claims.

For example, in the above-mentioned embodiment, there is shown an example in which the refrigerant discharging portion <NUM> of the oil guide <NUM> that is disposed to be opposed to the direct-coupling-side stator coil end 42B is an opened hole formed in the arc portion <NUM>. However, the refrigerant discharging portion <NUM> may be formed to project from the arc portion <NUM> toward the side of the stator coil end 42B.

Furthermore, in the above-mentioned embodiment, there is shown an example in which each of the oil guides <NUM>, <NUM> is formed in one piece. However, as long as refrigerant can be ejected from the tip end of the projection portion that extends from the arc portion <NUM> toward the inner peripheral surface of the casing <NUM>, for example, the arc portion <NUM>, <NUM> may be separated into those in a semicircular shape by a lower portion.

Furthermore, it is possible to change the length of the refrigerant discharging portion <NUM> according to need.

Furthermore, in the above-mentioned embodiment, there is shown an example in which the refrigerant introducing portion <NUM> is installed on the inner side of the casing <NUM>. However, the refrigerant introducing portion <NUM> may be embedded in the inside of the frame <NUM> or may be directly formed in the frame <NUM>.

Furthermore, in the above-mentioned embodiment, there is shown an example in which both ends of oil guide <NUM>, <NUM> are connected to the refrigerant supply ports <NUM>, <NUM>. However, it is optional to form the arc portion <NUM>, <NUM> into a closed shape (annular shape) and connect a refrigerant-supplying communication portion to this annular shape portion.

Claim 1:
A cooling structure for a stator (<NUM>) of a rotating electrical machine for supplying
a refrigerant to stator coil ends (42A), the cooling structure being equipped with an oil guide (<NUM>) that is arranged in a casing (<NUM>) of the rotating electrical machine, the oil guide (<NUM>) comprising:
an arc-shaped tube (<NUM>) forming a first refrigerant passage therein, the arc-shaped tube (<NUM>) being arranged in a plane perpendicular to the stator axis and being opposed to an axial end portion of a stator coil end (42A), the arc-shaped tube (<NUM>) being configured such that, during operation, the refrigerant is introduced into the first refrigerant passage; and
a first refrigerant discharging portion (<NUM>) that projects in a first axial direction from a surface of the arc-shaped tube (<NUM>) toward the stator coil end (42A) of each unit coil (42a), the first refrigerant discharging portion (<NUM>) forming therein a second refrigerant passage communicating with the first refrigerant passage such that the refrigerant, during operation, passes from the first refrigerant passage to the second refrigerant passage, and then is discharged from a tip end of the first refrigerant discharging portion (<NUM>) toward the stator coil end (42A) of each unit coil (42a),
characterized in that the oil guide (<NUM>) further comprises a second refrigerant discharging portion (<NUM>) positioned during operation above a bearing (<NUM>) that supports a rotation shaft (<NUM>) of the rotating electrical machine, the bearing (<NUM>) being provided on an inner peripheral surface of the casing (<NUM>), the second refrigerant discharging portion (<NUM>) projecting in a second axial direction, which is opposite to the first axial direction, from a surface of the arc-shaped tube (<NUM>) and being configured to discharge the refrigerant from a tip end of the second refrigerant discharging portion (<NUM>) toward the inner peripheral surface of the casing (<NUM>) to supply the refrigerant for the cooling and lubrication of the bearing (<NUM>).