Patent Description:
<CIT> describes that when a passage through which a cooling liquid for cooling a rotating electrical machine flows is formed in a housing, the passage is formed by a circumferential passage along an outer periphery of a cylindrical housing and an oblique passage connecting each circumferential passage. In particular, the document describes that a width of the oblique passage should be the same as that of the circumferential passage in order to suppress an increase in pressure loss. <CIT> describes a rotary electric machine which includes an annular stator; an annular stator holder which holds the stator from a radial outer side; and a housing which encloses the stator holder. A passage seal member having elasticity and extending in a circumferential direction of the stator is sandwiched between an outer peripheral surface of the stator holder and an inner peripheral surface of the housing. The passage seal member defines a flow passage in which the cooling medium flows between the outer peripheral surface of the stator holder and the inner peripheral surface of the housing. <CIT> describes a rotary electric machine comprising a rotor, a stator and a cooling device. The cooling device comprises a channel for the circulation of a heat transfer liquid. The channel comprises substantially circumferential zones in which the channel is subdivided into several passages. The canal further comprises substantially helicoidal zones, in which the channel is not subdivided. <CIT> describes a rotating electric machine having both high cooling efficiency and low pressure loss. This rotating electric machine is configured so as to have: a stator; a rotor rotatably held within the stator with a prescribed gap therebetween; and a cooling liquid passage located at the outer periphery of the stator and formed within a housing. The cooling liquid path comprises a cooling liquid inlet provided at one end of the cooling liquid path, a cooling liquid outlet provided at the other end, circumferential passages arranged in multiple rows in the axial direction, orthogonal to the circumferential direction; and an oblique passage connecting the circumferential passages in the axial direction. The circumferential passages and the oblique passage are connected such that the direction of flow of the cooling liquid in each circumferential passage is the same in the circumferential direction. <CIT> describes an electric motor which has a rotor, at least two magnet segments, a magnetic return path ring and a housing consisting of aluminum. The housing has at least one helical projection on its outer side parallel to the longitudinal axis of the electric motor. An outer cover in the form of a cup is arranged around the housing, the at least one helical projection bearing against the inner side of said outer cover, wherein the outer cover in the form of a cup has a coolant inlet and a coolant outlet.

When a flow path (passage) through which a refrigerant flows is formed in a housing of a rotating electrical machine, it is necessary to particularly consider a relative positional relation between an inlet through which the refrigerant flows into the flow path and an outlet through which the refrigerant flows out from the flow path.

For example, as in the housing described in the above document, when an inlet and an outlet of the refrigerant are located at substantially the same position in a circumferential direction of the housing, a flow path of a refrigerant can be formed to cover substantially an entire circumferential surface of the housing.

However, the rotating electrical machine is used by being incorporated in a drive unit or the like that drives a vehicle. Therefore, for example, the arrangement of the inlet and the outlet of the refrigerant may be limited by an arrangement relation of other members constituting the drive unit. That is, the inlet and the outlet of the refrigerant may be arranged at positions separated from each other in the circumferential direction of the housing. In this case, depending on an angular range in which the inlet and outlet of the refrigerant are spaced apart from each other, a portion without a flow path of the refrigerant is generated on the circumferential surface of the housing. For example, when the inlet and outlet of the refrigerant are shifted by <NUM> degrees in the circumferential direction of the housing, a portion without a flow path of the refrigerant is generated over half the circumference at an end of the housing. When there is such a portion without a flow path, a problem that the rotating electrical machine is not sufficiently cooled occurs.

An object of the present invention is to provide a rotating electrical machine formed with a flow path of a refrigerant in a housing, in which necessary cooling performance can be obtained regardless of a positional relation between an inlet and an outlet of the refrigerant.

A rotating electrical machine according to one aspect of the present invention is defined in claim <NUM>.

<FIG> is a schematic cross-sectional view of a drive unit <NUM>. The drive unit <NUM> is a unit for directly or indirectly controlling driving of a vehicle (not shown) such as an electric vehicle or a hybrid vehicle using a rotating electrical machine <NUM>. The direct drive control using the rotating electrical machine <NUM> is, for example, a control mode in which a torque generated by the rotating electrical machine <NUM> is converted into a driving force of the vehicle. The indirect drive control using the rotating electrical machine <NUM> is, for example, a control mode in which the rotating electrical machine <NUM> is used for power generation, and a part or all of electric power generated by the power generation is used to generate a driving force of the vehicle. The drive unit <NUM> of the present embodiment is mounted on a series hybrid electric vehicle. Therefore, the drive unit <NUM> controls the driving of the vehicle directly and indirectly.

As shown in <FIG>, the drive unit <NUM> includes the rotating electrical machine <NUM> and an inverter <NUM> that controls an operation of the rotating electrical machine <NUM> in an outer housing <NUM>. In addition to the rotating electrical machine <NUM> and the inverter <NUM>, the drive unit <NUM> is configured integrally with members (not shown) such as gears constituting a speed reducer and a rotation sensor.

The outer housing <NUM> is a housing that forms an outer shell of the drive unit <NUM>. The rotating electrical machine <NUM>, the inverter <NUM>, and the like are accommodated in the outer housing <NUM>, thereby being integrated as the drive unit <NUM>. A flow path (hereinafter, referred to as a refrigerant flow path) <NUM> through which a refrigerant <NUM> that cools a heating element such as the rotating electrical machine <NUM> and the inverter <NUM> flows is provided in the outer housing <NUM>. The refrigerant <NUM> is a fluid such as a liquid or a gas supplied for cooling, and is, for example, cooling water, other cooling liquid or air, and the like. The refrigerant <NUM> flows through the refrigerant flow path <NUM> and the like, thereby cooling each part accommodated in the outer housing <NUM>, such as the rotating electrical machine <NUM>, the inverter <NUM>, and other heating elements (not shown). In the present embodiment, the refrigerant <NUM> is a cooling liquid that circulates between radiators (not shown).

The rotating electrical machine <NUM> is a motor, a generator, or a motor generator that operates as a motor and a generator. The rotating electrical machine <NUM> may include two or more motors that operate as a motor, a generator, or a motor generator. In the present embodiment, the rotating electrical machine <NUM> includes two motors, that is, a first motor <NUM> and a second motor <NUM>. For this reason, the inverter <NUM> includes a first inverter 12a that controls the first motor <NUM> and a second inverter 12b that controls the second motor <NUM>.

The first motor <NUM> is a driving motor (electric motor). Therefore, the vehicle equipped with the drive unit <NUM> travels by converting a torque generated by the first motor <NUM> into a driving force. Electric power for driving the first motor <NUM> is supplied from a battery (not shown). The first motor <NUM> includes an inner housing <NUM>, a stator <NUM>, and a rotor <NUM>.

The inner housing <NUM> is a cylindrical member that fixes the stator <NUM> by a method such as shrink fitting. In the present embodiment, the inner housing <NUM> has a cylindrical shape. The inner housing <NUM> includes a refrigerant flow path <NUM> (see <FIG> and the like) that communicates with the refrigerant flow path <NUM> of the outer housing <NUM> therein. That is, the refrigerant flow path <NUM> is a flow path (passage) through which the refrigerant <NUM> flows. A structure of the inner housing <NUM> and a structure of the refrigerant flow path <NUM> of the inner housing <NUM> (hereinafter referred to as the refrigerant flow path <NUM> of the first motor <NUM>) will be described in detail later.

The rotor <NUM> is attached to the outer housing <NUM> and is inserted into a central portion of the stator <NUM> when the drive unit <NUM> is formed. The rotor <NUM> is rotatable with respect to the inner housing <NUM> and the stator <NUM> even after being inserted into the stator <NUM>. Since the stator <NUM> is a unit through which a current flows to control the first motor <NUM>, the stator <NUM> is at least one of heat generation factors of the first motor <NUM>.

The second motor <NUM> is a power generation motor (generator). The second motor <NUM> is connected to an engine (internal combustion engine) (not shown) and is driven by the engine. The electric power generated by the second motor <NUM> is accumulated in a battery that supplies electric power to the first motor <NUM>. The second motor <NUM> can consume the electric power of the battery by idling.

The second motor <NUM> is different in use from the first motor <NUM>, but has the same basic structure as the first motor <NUM>. That is, the second motor <NUM> includes an inner housing <NUM>, a stator <NUM>, and a rotor <NUM>. The inner housing <NUM> is a cylindrical member that fixes the stator <NUM> by a method such as shrink fitting, and has a cylindrical shape in the present embodiment. The inner housing <NUM> includes a refrigerant flow path <NUM> (see <FIG> and the like) that communicates with the refrigerant flow path <NUM> of the outer housing <NUM> therein. That is, the refrigerant flow path <NUM> is a flow path through which the refrigerant <NUM> flows. The refrigerant flow path <NUM> of the inner housing <NUM> (hereinafter, referred to as the refrigerant flow path <NUM> of the second motor <NUM>) has substantially the same basic structure as the refrigerant flow path <NUM> of the inner housing <NUM>. A structure of the refrigerant flow path <NUM> of the second motor <NUM> will be described in detail later together with a coupling structure of the first motor <NUM> and the second motor <NUM>. The rotor <NUM> is attached to the outer housing <NUM> and is rotatable even after being inserted into the stator <NUM>. Since the stator <NUM> is a unit through which a current flows to control the second motor <NUM>, the stator <NUM> is at least one of heat generation factors of the second motor <NUM>.

The inner housing <NUM> of the first motor <NUM> and the inner housing <NUM> of the second motor <NUM> are integrated by being coupled with a coupling pipe <NUM>. For this reason, the inner housing <NUM> of the first motor <NUM> and the inner housing <NUM> of the second motor <NUM> as a whole constitute an inner housing of the rotating electrical machine <NUM>. That is, the inner housing of the rotating electrical machine <NUM> includes a first housing and a second housing. The first housing is the inner housing <NUM> of the first motor <NUM>, accommodates the stator <NUM> as a first stator and the rotor <NUM> as a first rotor, and has the refrigerant flow path <NUM>. The second housing is the inner housing <NUM> of the second motor <NUM>, accommodates the stator <NUM> as a second stator and the rotor <NUM> as a second rotor, and has the refrigerant flow path <NUM>.

In addition to integrating the inner housings <NUM> and <NUM> as described above, the coupling pipe <NUM> couples the refrigerant flow path <NUM> of the first motor <NUM> and the refrigerant flow path <NUM> of the second motor <NUM>. In the present embodiment, the refrigerant <NUM> flowing into the outer housing <NUM> flows into the refrigerant flow path <NUM> of the first motor <NUM> after passing through the refrigerant flow path <NUM> to cool the inverter <NUM>. Thereafter, the refrigerant <NUM> flows through the refrigerant flow path <NUM> of the first motor <NUM> and flows out to the coupling pipe <NUM>. Therefore, a connection portion between the refrigerant flow path <NUM> of the outer housing <NUM> and the first motor <NUM> is an inlet (hereinafter referred to as an inlet α) of the refrigerant <NUM> in the refrigerant flow path <NUM> of the first motor <NUM>. A connection portion between the coupling pipe <NUM> and the first motor <NUM> is an outlet (hereinafter referred to as an outlet β) of the refrigerant <NUM> in the refrigerant flow path <NUM> of the first motor <NUM>. That is, in the refrigerant flow path <NUM> of the first motor <NUM>, the inlet α is an introduction port of the refrigerant <NUM>, and the outlet β is a discharge port of the refrigerant <NUM>.

The refrigerant <NUM> flows into the refrigerant flow path <NUM> of the second motor <NUM> through the coupling pipe <NUM>, flows through the refrigerant flow path <NUM> of the second motor <NUM>, and then flows out to the refrigerant flow path <NUM> of the outer housing <NUM>. Therefore, a connection portion between the coupling pipe <NUM> and the second motor <NUM> is an inlet (hereinafter referred to as an inlet γ) of the refrigerant <NUM> in the refrigerant flow path <NUM> of the second motor <NUM>. A connection portion between the refrigerant flow path <NUM> of the outer housing <NUM> and the second motor <NUM> is an outlet (hereinafter referred to as an outlet δ) of the refrigerant <NUM> in the refrigerant flow path <NUM> of the second motor <NUM>. That is, in the refrigerant flow path <NUM> of the second motor <NUM>, the inlet γ is an introduction port of the refrigerant <NUM>, and the outlet δ is a discharge port of the refrigerant <NUM>.

That is, the coupling pipe <NUM> linearly couples the outlet β of the inner housing <NUM> and the inlet γ of the inner housing <NUM> without waste. Accordingly, the coupling pipe <NUM> connects the refrigerant flow path <NUM> of the first motor <NUM> and the refrigerant flow path <NUM> of the second motor <NUM>.

In the present embodiment, rotation axes of the first motor <NUM> and the second motor <NUM> are parallel to each other. As shown in <FIG>, a direction of the rotation axes of the first motor <NUM> and the second motor <NUM> is defined as a Z direction, and an X direction and a Y direction are defined so as to form a right-handed system with reference to the Z direction. Further, as shown in <FIG>, for convenience of explanation, the refrigerant flow path <NUM> connected to the first motor <NUM> and the refrigerant flow path <NUM> connected to the second motor <NUM> are parallel to each other in the vicinity of the connection portions thereof. A connection direction of the refrigerant flow path <NUM> to the first motor <NUM> and the second motor <NUM> is defined as the Y direction.

<FIG> is a perspective view of the inner housing <NUM>. Although <FIG> shows the inner housing <NUM> of the first motor <NUM>, the inner housing <NUM> of the second motor <NUM> also has the same structure. As shown in <FIG>, the inner housing <NUM> of the first motor <NUM> has a double pipe structure including an inner pipe <NUM> and an outer pipe <NUM>, and the refrigerant flow path <NUM> of the first motor <NUM> is formed between the inner pipe <NUM> and the outer pipe <NUM>.

The inner pipe <NUM> is a substantially cylindrical member, and has a flange portion <NUM> at one end. The flange portion <NUM> is provided with a fastening portion <NUM>. Therefore, the flange portion <NUM> constitutes a mounting surface to the outer housing <NUM>. The flange portion <NUM> also functions as a positioning member of the outer pipe <NUM>. That is, when the outer pipe <NUM> is attached to the inner pipe <NUM> by engagement, screwing, or other methods, an end of the outer pipe <NUM> abuts against the flange portion <NUM> of the inner pipe <NUM>. Accordingly, a relative position between the inner pipe <NUM> and the outer pipe <NUM> in the Z direction is determined. The fastening portion <NUM> is a portion of the flange portion <NUM> that has screw holes for fastening the inner housing <NUM> to the outer housing <NUM>. The stator <NUM> is accommodated and fixed in the inner pipe <NUM>.

Hereinafter, among circumferential surfaces of the inner pipe <NUM>, a circumferential surface in contact with the stator <NUM> is referred to as an inner circumferential surface, and a circumferential surface in contact with the outer pipe <NUM> is referred to as an outer circumferential surface. Similarly, among circumferential surfaces of the outer pipe <NUM>, a circumferential surface on the outer circumferential surface side of the inner pipe <NUM> is referred to as an inner circumferential surface, and a circumferential surface forming an outer periphery of the inner housing <NUM> is referred to as an outer circumferential surface. For convenience of explanation, in the inner circumferential surface of the inner pipe <NUM>, the inner circumferential surface on the positive side in the X direction is referred to as a right inner circumferential surface <NUM>, and the inner circumferential surface on the negative side in the X direction is referred to as a left inner circumferential surface <NUM>. A surface at the end of the inner housing <NUM> is referred to as an end surface. In the present embodiment, for convenience, an end surface of the inner pipe <NUM> on the positive side in the Z direction where the flange portion <NUM> is provided is referred to as "one end surface <NUM>", and an end surface on the negative side in the Z direction is referred to as "the other end surface <NUM>".

The outer pipe <NUM> is attached to an outside of the inner pipe <NUM> so as to cover the outer circumferential surface of the inner pipe <NUM>. Further, when the outer pipe <NUM> is attached to the inner pipe <NUM>, the inner circumferential surface of the outer pipe <NUM> abuts against the outer circumferential surface of the inner pipe <NUM> except for a portion where the refrigerant flow path <NUM> is formed. For this reason, the refrigerant flow path <NUM> is kept watertight and airtight to the extent that the refrigerant <NUM> does not leak at least. The outer pipe <NUM> has a connecting pipe <NUM> connected to the refrigerant flow path <NUM> of the outer housing <NUM> at the inlet α of the refrigerant <NUM>. The connecting pipe <NUM> may be referred to as a bulge.

<FIG> is a perspective view of the inner pipe <NUM>. The inner pipe <NUM> has a series of grooves <NUM> along the outer circumferential surface. The grooves <NUM> are formed to surround the outer circumferential surface of the inner pipe <NUM>. Adjacent ones of the grooves <NUM> are separated by wall portions <NUM> due to the encirclement or the like. The wall portions <NUM> separate the one end surface <NUM> and the other end surface <NUM> from the grooves <NUM>. Top portions <NUM> (ridge portions) of the wall portions <NUM> abut against the inner circumferential surface of the outer pipe <NUM>. When the outer pipe <NUM> is attached to the inner pipe <NUM>, the refrigerant flow path <NUM> is formed by the inner circumferential surface of the outer pipe <NUM>, the grooves <NUM>, and the wall portions <NUM>.

<FIG> is a side view of the inner pipe <NUM>. <FIG> is a side view of the inner pipe <NUM> as viewed from another direction. As shown in <FIG> and <FIG>, the refrigerant flow path <NUM> is formed so as to spirally circulate along the outer circumferential surface of the inner pipe <NUM> from the inlet α to the outlet β. The refrigerant flow path <NUM> is provided in substantially the entire range (hereinafter referred to as a heat generation range <NUM>) in which heat is generated due to the presence of the stator <NUM> in the Z direction. For this reason, as indicated by dashed arrows, when the refrigerant <NUM> flows through the refrigerant flow path <NUM>, the entire stator <NUM> is cooled at least.

<FIG> is an explanatory view showing a detailed configuration of the refrigerant flow path <NUM>. As shown in <FIG>, hereinafter, a position of the refrigerant flow path <NUM> along the outer circumferential surface is represented by an angle in a plane (XY plane direction) perpendicular to the Z direction with reference to a position of the inlet α. An angle indicating a position in the refrigerant flow path <NUM> is referred to as an angular position. In the present embodiment, as shown in <FIG>, angular positions of the inlet α and the outlet β of the refrigerant <NUM> in the refrigerant flow path <NUM> are separated from each other, and an angular position of the inlet α is <NUM> degrees, whereas an angular position of the outlet β is <NUM> degrees. For this reason, the angular positions of the inlet α and the outlet β are separated by <NUM> degrees.

Regarding the angular positions of the inlet α and the outlet β, the term "separated" means that the inlet α and the outlet β are located at substantially different angular positions in consideration of sizes of the inlet α and the outlet β, a range in which the refrigerant <NUM> located at the inlet α and the outlet β cools the stator <NUM>, and the like. A structure of the refrigerant flow path <NUM> described in detail below is a structure for effectively cooling the accommodated stator <NUM> and the like even when the inlet α and the outlet β are separated. Therefore, it can be said that the positions of the inlet α and the outlet β are substantially separated from each other as long as a cooling effect of a part or the whole of the stator <NUM> is enhanced by adopting the structure of the refrigerant flow path <NUM>.

In addition, as the angular positions of the inlet α and the outlet β are separated, the structure of the refrigerant flow path <NUM> is more effective in relation to the cooling effect. When the inlet α and the outlet β are separated from each other by, for example, <NUM> degrees or more, a cooling performance improvement effect due to the structure of the refrigerant flow path <NUM> can be sufficiently expected. For example, when the inlet α and the outlet β are separated by <NUM> degrees or more, the cooling performance improvement effect due to the structure of the refrigerant flow path <NUM> tends to become remarkable. When the inlet α and the outlet β are separated by, for example, <NUM> degrees or more, the cooling performance improvement effect due to the structure of the refrigerant flow path <NUM> is particularly remarkable. In a case where a structure other than the refrigerant flow path <NUM> is adopted, the cooling effect is most likely to be reduced when the inlet α and the outlet β are separated by <NUM> degrees. For this reason, in a case where the inlet α and the outlet β are separated by <NUM> degrees, when the structure of the refrigerant flow path <NUM> is adopted, the cooling effect is most improved.

As shown in <FIG>, the refrigerant flow path <NUM> includes a first flow path <NUM> and a second flow path <NUM>. In the present embodiment, the refrigerant flow path <NUM> includes a third flow path <NUM> in addition to the first flow path <NUM> and the second flow path <NUM>.

The first flow path <NUM> is formed along the one end surface <NUM> of the inner housing <NUM> from the inlet α, and is formed such that a width along the circumferential surface increases along a flow direction of the refrigerant <NUM>. In particular, in the present embodiment, the first flow path <NUM> is provided in a range extending around the circumferential surface of the inner housing <NUM> from the inlet α.

The expression "formed along the one end surface <NUM>" means that a part or the whole of a first round closest to the one end surface <NUM> is included as a constituent element in the refrigerant flow path <NUM> surrounding the circumferential surface of the inner housing <NUM>. In the present embodiment, the first flow path <NUM> is a portion of the refrigerant flow path <NUM> corresponding to the first round from the inlet α, that is, a portion having an angular position of <NUM> degrees to <NUM> degrees. In particular, in the first flow path <NUM>, the wall portion <NUM> and the top portion <NUM> thereof on the one end surface <NUM> side are formed parallel to the one end surface <NUM>. Therefore, in a narrower sense, the first flow path <NUM> is formed along the one end surface <NUM> even when considering a positional relation between the one end surface <NUM> and the wall portion <NUM> forming the first flow path <NUM>.

The flow direction of the refrigerant <NUM> in the refrigerant flow path <NUM> is a direction along the refrigerant flow path <NUM> from the inlet α to the outlet β. In the first flow path <NUM>, the flow direction of the refrigerant <NUM> is a positive direction (direction from <NUM> degrees to <NUM> degrees) of a lower angular position with respect to the inlet α.

The "width along the circumferential surface" refers to a length in the Z direction, that is, an interval between the wall portions <NUM> (particularly, top portions <NUM>) in the Z direction. As shown in <FIG>, the first flow path <NUM> is formed such that the width along the circumferential surface gradually increases as the angular position increases from <NUM> degrees. As indicated by a dashed line in <FIG>, when the inlet α and the outlet β are coupled by a spiral flow path having a uniform width, the flow path is defined as a reference flow path <NUM>. A width along a circumferential surface of the reference flow path <NUM> is defined as a reference width. At this time, the first flow path <NUM> has a shape obtained by expanding the flow path with the reference width, that is, the reference flow path <NUM> in a direction (positive direction in the Z direction) of the one end surface <NUM> of the inner housing <NUM>. The reference width that is the width of the reference flow path <NUM> is determined according to an allowable pressure loss of the refrigerant <NUM> at the inlet α and the outlet β.

The second flow path <NUM> is formed along the other end surface <NUM> of the inner housing <NUM>, and is formed such that the width along the circumferential surface decreases toward the outlet β along the flow direction of the refrigerant <NUM>. In particular, in the present embodiment, the second flow path <NUM> is provided in a range extending around the circumferential surface of the inner housing <NUM> from the outlet β.

The expression "formed along the other end surface <NUM>" means that a part or the whole of a last round closest to the other end surface <NUM> is included as a constituent element in the refrigerant flow path <NUM> surrounding the circumferential surface of the inner housing <NUM>. In the present embodiment, the second flow path <NUM> is the last round of the refrigerant flow path <NUM> reaching the outlet β, that is, a portion having an angular position of <NUM> degrees to <NUM> degrees. In particular, in the second flow path <NUM>, the wall portion and the top portion <NUM> thereof on the other end surface <NUM> side are formed parallel to the other end surface <NUM>. Therefore, in a narrower sense, the second flow path <NUM> is formed along the other end surface <NUM> even when considering a positional relation between the other end surface <NUM> and the wall portion <NUM> forming the second flow path <NUM>.

The flowing direction of the refrigerant <NUM> in the second flow path <NUM> is a direction along the outlet β from an angular position of <NUM> degrees. As shown in <FIG>, the second flow path <NUM> is formed such that the width along the circumferential surface gradually decreases as the angular position increases from the angular position of <NUM> degrees to the outlet β. In particular, the second flow path <NUM> has a shape obtained by expanding the reference flow path <NUM>, which is the flow path with the reference width, in a direction (negative direction in the Z direction) of the other end surface <NUM> of the inner housing <NUM>.

The third flow path <NUM> is a flow path of the refrigerant <NUM> that is provided between the first flow path <NUM> and the second flow path <NUM> and couples the first flow path <NUM> and the second flow path <NUM>. The third flow path <NUM> is formed to have a uniform width along the circumferential surface. The width of the third flow path <NUM> is formed to be narrower than a width of a widest portion of the first flow path <NUM> and narrower than a width of a widest portion of the second flow path <NUM>. In the present embodiment, as indicated by hatching in <FIG>, the third flow path <NUM> is a portion at an angular position of <NUM> degrees to <NUM> degrees. In particular, in the present embodiment, the width of the third flow path <NUM> is equal to the reference width which is the width of the reference flow path <NUM>. The structure of the third flow path <NUM> contributes to suppression of the pressure loss of the refrigerant <NUM>, particularly to minimization of the pressure loss.

A boundary between the first flow path <NUM> and the third flow path <NUM> and a boundary between the second flow path <NUM> and the third flow path <NUM> are formed by straight lines along a circumferential direction of the inner housing <NUM>. Furthermore, in the present embodiment, the boundary between the first flow path <NUM> and the second flow path <NUM> is also formed by a straight line along the circumferential direction of the inner housing <NUM>. The straight line corresponds to the wall portion <NUM> when the reference flow path <NUM> is formed. In this way, the boundaries of the first flow path <NUM>, the second flow path <NUM>, and/or the third flow path <NUM> are formed by the straight lines in order to reduce the pressure loss of the refrigerant <NUM> and further improve the cooling performance by substantially conforming to the reference flow path <NUM>.

Hereinafter, the action of the refrigerant flow path <NUM> configured as described above will be described in comparison with a refrigerant flow path <NUM> of a comparative example.

<FIG> is an explanatory view showing a configuration of the refrigerant flow path <NUM> of the comparative example. In the comparative example, the configuration of the inner housing <NUM> other than the refrigerant flow path <NUM>, such as the angular positions of the inlet α and the outlet β of the refrigerant <NUM>, is the same as that of the inner housing <NUM> of the present embodiment. As shown in <FIG>, the refrigerant flow path <NUM> of the comparative example is configured to surround the circumferential surface of the inner housing <NUM> by a parallel flow path <NUM> and an inclined flow path <NUM>. The parallel flow path <NUM> is a flow path of the refrigerant <NUM> and is parallel to the one end surface <NUM> and the other end surface <NUM>. A width of the parallel flow path <NUM> along the circumferential surface is uniform. The inclined flow path <NUM> is a flow path of the refrigerant <NUM> provided at a connection portion of the parallel flow path <NUM>, and is formed to be inclined with respect to the parallel flow path <NUM>. A width of the inclined flow path <NUM> in a direction perpendicular to the flow direction of the refrigerant <NUM> is the same as that of the parallel flow path <NUM>.

As shown in <FIG>, in a case where the refrigerant flow path <NUM> is formed by the parallel flow path <NUM>, a portion where the refrigerant flow path <NUM> is not formed (hereinafter referred to as a flow path non-forming portion <NUM>) is generated in the heat generation range <NUM> according to a separation angle between the inlet α and the outlet β. Of course, the refrigerant flow path <NUM> can also be formed by formally extending the parallel flow path <NUM> to the flow path non-forming portion <NUM> prior to the outlet β, but in such a formal flow path, the refrigerant <NUM> stays, and thus a substantial cooling effect is significantly reduced. For this reason, the extended portion of the formal parallel flow path <NUM> cannot be said to be a substantial refrigerant flow path.

<FIG> is an explanatory view showing an inner surface temperature of the inner housing <NUM> employing the refrigerant flow path <NUM> of the comparative example. (A) of <FIG> shows a temperature distribution of the left inner circumferential surface <NUM> when the refrigerant flow path <NUM> of the comparative example is adopted. (B) of <FIG> shows a temperature distribution of the right inner circumferential surface <NUM> when the refrigerant flow path <NUM> of the comparative example is adopted. In <FIG>, a portion having a higher density (black) indicates a higher temperature.

As shown in <FIG>, when the refrigerant flow path <NUM> of the comparative example is adopted, a significant high-temperature portion <NUM> exceeding an allowable limit is generated on the right inner circumferential surface <NUM> and the left inner circumferential surface <NUM>. The high-temperature portion <NUM> corresponds to the flow path non-forming portion <NUM>. That is, in the refrigerant flow path <NUM> of the comparative example, the flow path non-forming portion <NUM> is inevitably formed, and as a result, the high-temperature portion <NUM> is generated. For this reason, in the refrigerant flow path <NUM> of the comparative example, there is a failure that the first motor <NUM> is not sufficiently cooled.

<FIG> is an explanatory view showing an inner surface temperature of the inner housing <NUM> employing the refrigerant flow path <NUM> according to the present embodiment. (A) of <FIG> shows a temperature distribution of the left inner circumferential surface <NUM> when the refrigerant flow path <NUM> of the present embodiment is adopted. (B) of <FIG> shows a temperature distribution of the right inner circumferential surface <NUM> when the refrigerant flow path <NUM> of the present embodiment is adopted. In <FIG>, a portion having a higher density (black) indicates a higher temperature.

As indicated by a dashed line in <FIG>, the significant high-temperature portion <NUM> is generated in the refrigerant flow path <NUM> of the comparative example, whereas the high-temperature portion <NUM> is not generated when the refrigerant flow path <NUM> according to the present embodiment is adopted. Therefore, the refrigerant flow path <NUM> according to the present embodiment can sufficiently cool the first motor <NUM>.

As described above, the reason why the refrigerant flow path <NUM> according to the present embodiment can sufficiently cool the first motor <NUM> without generating the high-temperature portion <NUM> is that the refrigerant flow path <NUM> includes at least the first flow path <NUM> and the second flow path <NUM>.

Specifically, the first flow path <NUM> has a structure in which the width thereof gradually increases from the inlet α. For this reason, since the refrigerant flow path <NUM> includes the first flow path <NUM>, the refrigerant flow path <NUM> has a structure in which the flow path non-forming portion <NUM> is not formed at the end at least on the one end surface <NUM> side in the heat generation range <NUM>. The second flow path <NUM> has a structure in which the width thereof gradually decreases toward the outlet β. For this reason, since the refrigerant flow path <NUM> includes the second flow path <NUM>, the refrigerant flow path <NUM> has a structure in which the flow path non-forming portion <NUM> is not formed at the end at least on the other end surface <NUM> side in the heat generation range <NUM>.

Therefore, since the refrigerant flow path <NUM> includes the first flow path <NUM> and the second flow path <NUM>, the refrigerant flow path <NUM> has a structure in which the flow path non-forming portion <NUM> is not formed and almost the entire heat generation range <NUM> is cooled by the refrigerant <NUM>. As a result, compared to the refrigerant flow path <NUM> of the comparative example in which the flow path non-forming portion <NUM> is generated due to the separation between the inlet α and the outlet β, the refrigerant flow path <NUM> according to the present embodiment can cool almost the entire heat generation range <NUM> by the refrigerant <NUM> flowing therethrough. For this reason, the refrigerant flow path <NUM> according to the present embodiment can sufficiently cool the first motor <NUM>.

<FIG> is an explanatory view showing a flow velocity of the refrigerant <NUM> in the refrigerant flow path <NUM> according to the present embodiment. In <FIG>, a portion having a higher density (black) indicates a higher flow velocity, and a portion having a lower density (white) indicates a lower flow velocity. However, a white band at an angular position of more than <NUM> degrees is merely a missing part of data due to simulation settings, and does not indicate that the flow velocity of the refrigerant <NUM> is low.

As shown in <FIG>, in the refrigerant flow path <NUM>, due to a relation between structures to be satisfied by the first flow path <NUM> and the third flow path <NUM>, the connection portion therebetween becomes a steep contraction portion <NUM> in which the width along the circumferential direction is suddenly contracted. In the refrigerant flow path <NUM>, due to the relation between the structures to be satisfied by the third flow path <NUM> and the second flow path <NUM>, the connection portion therebetween becomes a steep expansion portion <NUM> in which the width along the circumferential direction is suddenly expanded.

In general, when a flow path of a fluid is rapidly contracted or rapidly expanded, a velocity (flow velocity) of the fluid is locally and remarkably decreased in the portion, and a large pressure loss occurs. However, in the refrigerant flow path <NUM>, the structures of the first flow path <NUM> and the second flow path <NUM> prevent a local and remarkable velocity decrease in the vicinity of the steep contraction portion <NUM> and the steep expansion portion <NUM>. As a result, in the refrigerant flow path <NUM>, the pressure loss in the steep contraction portion <NUM> and the steep expansion portion <NUM> is suppressed, and sufficient cooling performance is realized including the steep contraction portion <NUM> and the steep expansion portion <NUM>.

Specifically, since the first flow path <NUM> is formed such that the width thereof gradually increases, the refrigerant <NUM> flows through the first flow path <NUM> from the inlet α, and thus the velocity thereof gradually decreases over a long distance. For this reason, also in the first flow path <NUM> whose width is increased with respect to the reference flow path <NUM>, the refrigerant <NUM> diffuses to almost every corner. For example, as shown in <FIG>, in the steep contraction portion <NUM> which is the end of the first flow path <NUM>, the refrigerant <NUM> is easily diffused to corners. As a result, a portion on the one end surface <NUM> side in the heat generation rang <NUM> is sufficiently cooled by the structure of the first flow path <NUM>.

In the first flow path <NUM>, the velocity of the refrigerant <NUM> decreases, but a change in velocity is gentle, and a locally large decrease in flow velocity does not occur. For this reason, an energy loss proportional to the square of the velocity of the refrigerant <NUM> can be suppressed. As a result, a change in pressure of the refrigerant <NUM> in the first flow path <NUM> becomes gentle, and no significant pressure loss occurs in the first flow path <NUM>.

Thereafter, the velocity of the refrigerant <NUM> is reduced by passing through the first flow path <NUM>, and the refrigerant <NUM> reaches the steep contraction portion <NUM> in a state of high diffusibility. Accordingly, the refrigerant <NUM> can flow into the third flow path <NUM> without large energy loss at the steep contraction portion <NUM>. That is, the refrigerant flow path <NUM> reduces the pressure loss at the steep contraction portion <NUM> by the structure of the first flow path <NUM>.

Similar to the first flow path <NUM>, since the second flow path <NUM> is formed such that the width thereof gradually decreases, the refrigerant <NUM> flows through the second flow path <NUM> toward the outlet β, and thus the velocity thereof gradually increases over a long distance. For this reason, also in the second flow path <NUM> whose width is increased with respect to the reference flow path <NUM>, the refrigerant <NUM> diffuses to almost every corner. For example, as shown in <FIG>, in the steep expansion portion <NUM> which is the beginning of the second flow path <NUM>, the refrigerant <NUM> is easily diffused to corners. As a result, a portion on the other end surface <NUM> side in the heat generation rang <NUM> is sufficiently cooled by the structure of the second flow path <NUM>. In particular, since the refrigerant flow path <NUM> is formed in a spiral shape, the flow direction of the refrigerant <NUM> in the steep expansion portion <NUM> is inclined toward the other end surface <NUM>. For this reason, the refrigerant <NUM> flowing in from the third flow path <NUM> flows in a direction of the wall portion <NUM> parallel to the other end surface <NUM>. As a result, the refrigerant <NUM> easily diffuses to the corners of the steep expansion portion <NUM>. In this way, since the refrigerant <NUM> is easily diffused also in the steep expansion portion <NUM>, a local velocity decrease and a pressure loss in the steep expansion portion <NUM> or in the vicinity thereof are suppressed.

In the second flow path <NUM>, the velocity of the refrigerant <NUM> changes (increases), but the change in velocity is gentle, and a locally large change in flow velocity does not occur. For this reason, an energy loss proportional to the square of the velocity of the refrigerant <NUM> can be suppressed. As a result, a change in pressure of the refrigerant <NUM> in the second flow path <NUM> becomes gentle, and no significant pressure loss occurs in the second flow path <NUM>.

As described above, the refrigerant flow path <NUM> is configured to suppress the pressure loss of the refrigerant <NUM> by the first flow path <NUM> and the second flow path <NUM>, and the effect of suppressing the pressure loss is remarkable to the extent that the pressure loss is suppressed better than the refrigerant flow path <NUM> of the comparative example. That is, in comparison with the pressure loss of the refrigerant <NUM>, the pressure loss of the refrigerant <NUM> at the outlet β of the refrigerant flow path <NUM> according to the present embodiment is smaller than the pressure loss of the refrigerant <NUM> at the outlet β of the refrigerant flow path <NUM> of the comparative example.

<FIG> is a graph schematically showing changes in flow velocity and temperature of the refrigerant <NUM>. As shown in <FIG>, in the refrigerant flow path <NUM>, the velocity of the refrigerant <NUM> is low and the temperature thereof is high in the vicinity of the steep expansion portion <NUM>. For this reason, the steep expansion portion <NUM> and the vicinity thereof are the most severe environment for the cooling performance of the first motor <NUM>, and are likely to reach a high temperature. However, as shown in <FIG>, the temperature does not become extremely high even in the portion corresponding to the steep expansion portion <NUM>, and the right inner circumferential surface <NUM> and left inner circumferential surface <NUM> that abut against the stator <NUM> as a whole are sufficiently cooled by the refrigerant flow path <NUM>.

<FIG> is an explanatory view showing a configuration of a refrigerant flow path of the entire rotating electrical machine <NUM>. As shown in <FIG>, the refrigerant flow path <NUM> of the first motor <NUM> extends from the inlet α in the positive direction of the Z direction in a right-handed spiral and reaches the outlet β. On the other hand, the refrigerant flow path <NUM> of the second motor <NUM> extends from the inlet γ in the negative direction of the Z direction in a left-handed spiral and reaches the outlet δ. That is, the refrigerant flow path <NUM> of the first motor <NUM> and the refrigerant flow path <NUM> of the second motor <NUM> are different in helicity (or chirality), and are spirally wound in opposite directions. As described above, in a case where the refrigerant flow path <NUM> of the first motor <NUM> and the refrigerant flow path <NUM> of the second motor <NUM> are formed in a spiral shape in which the two refrigerant flow paths <NUM> and <NUM> are wound in opposite directions to each other, the refrigerant flow path <NUM> of the first motor <NUM> and the refrigerant flow path <NUM> of the second motor <NUM> can be linearly connected to each other in a shortest length by the coupling pipe <NUM> without providing a needlessly long connecting pipe. For this reason, the first motor <NUM> and the second motor <NUM> are disposed in a space-saving manner, and a compact rotating electrical machine <NUM> is provided. In addition, in a case where the refrigerant flow path <NUM> of the first motor <NUM> and the refrigerant flow path <NUM> of the second motor <NUM> are formed in a spiral shape in which the two refrigerant flow paths <NUM> and <NUM> are wound in opposite directions to each other, it is possible to easily align respective attachment surfaces of the first motor <NUM> and the second motor <NUM> with respect to the outer housing <NUM>, and it is easy to arrange the first motor <NUM> and the second motor <NUM> in a space-saving manner compared to a case where the respective attachment surfaces are not aligned.

The refrigerant flow path <NUM> of the second motor <NUM> is formed in a spiral shape that is wound in a reverse direction with respect to the refrigerant flow path <NUM> of the first motor <NUM> as described above, but the basic structure thereof is the same as that of the refrigerant flow path <NUM> of the first motor <NUM>. The inner housing <NUM> of the second motor <NUM> is formed by an inner pipe <NUM> and an outer pipe <NUM>, similar to the inner housing <NUM> of the first motor <NUM>. The refrigerant flow path <NUM> of the second motor <NUM> is formed on an outer circumferential surface of the inner pipe <NUM>. In the inner pipe <NUM>, an end surface on the positive side in the Z direction where a flange portion is provided is one end surface <NUM>, and an end surface on the negative side in the Z direction is the other end surface <NUM>.

The refrigerant flow path <NUM> of the second motor <NUM> includes a first flow path <NUM> and a second flow path <NUM>. In the present embodiment, the refrigerant flow path <NUM> of the second motor <NUM> further includes a third flow path <NUM>. The first flow path <NUM> is formed along the one end surface <NUM> of the inner housing <NUM>, and is formed such that a width along the circumferential surface increases along the flow direction of the refrigerant <NUM>. The second flow path <NUM> is formed along the other end surface <NUM> of the inner housing <NUM> from the inlet γ, and is formed such that a width along the circumferential surface decreases toward the outlet δ along the flow direction of the refrigerant <NUM>. The third flow path <NUM> is formed between the first flow path <NUM> and the second flow path <NUM> so that the width along the circumferential surface is uniform, and couples the first flow path <NUM> and the second flow path <NUM>. That is, the refrigerant flow path <NUM> of the second motor <NUM> is formed in the same manner as the refrigerant flow path <NUM> of the first motor <NUM> except that the refrigerant flow path <NUM> is wound in a reverse direction.

In a case where the drive unit <NUM> is provided with a rotating electrical machine in which a plurality of motors are arranged in a compact manner as in the rotating electrical machine <NUM>, the refrigerant flow path <NUM> of the outer housing <NUM> is preferably formed as shown in <FIG>, for example. That is, in order to form the drive unit <NUM> in a compact manner, it is preferable that the refrigerant flow paths <NUM> of the outer housing <NUM> couples the respective portions constituting the drive unit <NUM> by substantially the shortest route. However, when the refrigerant flow path <NUM> of the outer housing <NUM> is formed in this manner, the inlet and the outlet of the refrigerant to each of motors constituting the rotating electrical machine are separated from each other. When the drive unit <NUM> is configured to be particularly compact, the inlet and the outlet of the refrigerant flow path in each of the motors constituting the rotating electrical machine are separated by about <NUM> degrees. This is as shown in <FIG> and the like by the inlet α and the outlet β of the refrigerant flow path <NUM> of the first motor <NUM> and the inlet γ and the outlet δ of the refrigerant flow path <NUM> of the second motor <NUM>.

On the other hand, considering only the cooling performance of the first motor <NUM>, it is desirable that the inlet α and the outlet β of the refrigerant flow path <NUM> of the first motor <NUM> are not separated from each other so that the flow path non-forming portion <NUM> is substantially not formed. The same applies to the second motor <NUM>. That is, considering only the cooling performance for each of the motors constituting the rotating electrical machine, it is desirable that the inlet and the outlet of the refrigerant flow path are not substantially separated. However, in consideration of the cooling performance of the first motor <NUM> and/or the second motor <NUM> alone, the redundancy of the refrigerant flow path <NUM> of the outer housing <NUM> results in a disadvantage that the drive unit <NUM> cannot be configured compactly.

Therefore, according to the present embodiment, the structures of the refrigerant flow path <NUM> and the refrigerant flow path <NUM>, and the coupling structures thereof are the best structures that enable the drive unit <NUM> to be formed as compact as possible with respect to the flow path of the refrigerant <NUM>, and further maximize the cooling performance of the first motor <NUM> and the second motor <NUM>.

In the above embodiment, in addition to the first flow path <NUM> and the second flow path <NUM>, the refrigerant flow path <NUM> of the first motor <NUM> includes the third flow path <NUM> coupling the first flow path <NUM> and the second flow path <NUM>. Further, in addition to the first flow path <NUM> and the second flow path <NUM>, the refrigerant flow path <NUM> of the second motor <NUM> also includes a third flow path <NUM> coupling the first flow path <NUM> and the second flow path <NUM>. However, the third flow paths <NUM> and <NUM> may be omitted in consideration of cooling performance, pressure loss, and the like. This omission however is not according to the invention. Also in this case, the same effects as those of the refrigerant flow path <NUM> and the like according to the above embodiment can be obtained.

<FIG> is an explanatory view showing a configuration of a refrigerant flow path <NUM> according to a first modification which is not according to the invention. The refrigerant flow path <NUM> of the modification is a refrigerant flow path in which the third flow path <NUM> in the refrigerant flow path <NUM> of the first motor <NUM> is omitted and the first flow path <NUM> and the second flow path <NUM> are directly coupled. In the refrigerant flow path <NUM> of the modification, a range of an angular position of <NUM> degrees (inlet α) to <NUM> degrees or <NUM> degrees is a range formed along the one end surface <NUM> and formed such that the width along the circumferential surface increases along the flow direction of the refrigerant <NUM>. Therefore, in the refrigerant flow path <NUM> of the modification, the range of <NUM> degrees to <NUM> degrees or <NUM> degrees is the first flow path <NUM>.

Similarly, in the refrigerant flow path <NUM> of the modification, a range of an angular position of <NUM> degrees or <NUM> degrees to <NUM> degrees (outlet β) is a range formed along the other end surface <NUM> and formed such that the width along the circumferential surface decreases toward the outlet β along the flow direction of the refrigerant <NUM>. Therefore, in the refrigerant flow path <NUM>, the range of <NUM> degrees or <NUM> degrees to <NUM> degrees (outlet β) is the second flow path <NUM>.

The range of the angular position of <NUM> degrees to <NUM> degrees satisfies a condition for the first flow path <NUM> by being grasped integrally with the first flow path <NUM>, and satisfies a condition for the second flow path <NUM> by being grasped integrally with the second flow path <NUM>, as described above. For this reason, the range of the angular position of <NUM> degrees to <NUM> degrees can belong to both the first flow path <NUM> and the second flow path <NUM>. In addition, since the width along the circumferential direction is larger than that of the reference flow path <NUM>, it is different from the third flow paths <NUM> and <NUM>. Therefore, the range of the angular position of <NUM> degrees to <NUM> degrees belongs to one or both of the first flow path <NUM> and the second flow path <NUM>.

In the above embodiment, the refrigerant flow path <NUM> of the first motor <NUM> includes the third flow path <NUM>, and the refrigerant flow path <NUM> of the second motor <NUM> includes the third flow path <NUM>. The third flow paths <NUM> and <NUM> are provided over half the circumference of the inner housings <NUM> and <NUM>. However, the number of turns of the third flow paths <NUM> and <NUM> can be freely changed by adaptation in accordance with an allowable pressure loss (hereinafter referred to as an allowable pressure loss), dimensions of the inlets α and γ and the outlets β and δ, and the like.

<FIG> is an explanatory diagram showing a configuration of a refrigerant flow path <NUM> according to a second modification. As shown in <FIG>, for example, when the allowable pressure loss is large and a relatively large pressure loss is allowable, the number of turns of the third flow paths <NUM> and <NUM> can be increased. Conversely, when the allowable pressure loss is small and only a relatively small pressure loss is allowable, the number of turns of the third flow paths <NUM> and <NUM> can be reduced (see <FIG>).

Note that changing the number of turns of the third flow paths <NUM> and <NUM> is synonymous with changing the number of turns of the refrigerant flow paths <NUM> and <NUM>. The number of turns of the third flow paths <NUM> and <NUM> correlates with the width of the third flow paths <NUM> and <NUM> and a spiral angle (pitch) formed by the third flow paths <NUM> and <NUM> and the refrigerant flow paths <NUM> and <NUM>, and by determining one of these, the other parameters are automatically determined. Therefore, as in the second modification, instead of changing the number of turns of the third flow paths <NUM> and <NUM>, the width of the third flow paths <NUM> and <NUM> or the spiral angle formed by the third flow paths <NUM> and <NUM> and the refrigerant flow paths <NUM> and <NUM> may be changed. The allowable pressure loss is appropriately determined according to, for example, the dimensions of the stators <NUM> and <NUM>.

As described above, a rotating electrical machine <NUM> according to the present embodiment and the modifications includes an inner housing <NUM> (<NUM>) that is a cylindrical housing. The inner housing <NUM> (<NUM>) that is a cylindrical housing includes a refrigerant flow path <NUM> (<NUM>) configured to allow a refrigerant <NUM> to flow therethrough, an inlet α (γ) configured to allow the refrigerant <NUM> to flow into the refrigerant flow path <NUM> (<NUM>), and an outlet β (δ) configured to allow the refrigerant <NUM> to flow out of the refrigerant flow path <NUM> (<NUM>). The refrigerant flow path <NUM> is formed so as to spirally surround around a circumferential surface of the inner housing <NUM> (<NUM>). In addition, the refrigerant flow path <NUM> (<NUM>) includes a first flow path <NUM> (<NUM>) that is formed along one end surface <NUM> (<NUM>) of the inner housing <NUM> (<NUM>) and formed such that a width along the circumferential surface increases along a flow direction of the refrigerant <NUM> from the inlet α (γ), and a second flow path <NUM> (<NUM>) that is formed along the other end surface <NUM> (<NUM>) of the inner housing <NUM> (<NUM>) and formed such that a width along the circumferential surface decreases toward the outlet β (δ) along the flow direction of the refrigerant <NUM>.

As described above, in a case where the refrigerant flow path <NUM> (<NUM>) is provided in the inner housing <NUM> (<NUM>) of the rotating electrical machine <NUM> and the refrigerant flow path <NUM> (<NUM>) includes the first flow path <NUM> (<NUM>) and the second flow path <NUM> (<NUM>), a flow path non-forming portion <NUM> is substantially not formed even when the inlet α (γ) and the outlet β (δ) of the refrigerant <NUM> are separated from each other. The first flow path <NUM> (<NUM>) and the second flow path <NUM> (<NUM>) suppress a local decrease in velocity of the refrigerant <NUM> and an increase in pressure loss, and obtain sufficient cooling performance almost entirely. Thus, in the refrigerant flow path <NUM> (<NUM>), the first flow path <NUM> (<NUM>) and the second flow path <NUM> (<NUM>) allow substantially the entire heat generation range <NUM> to be cooled by the refrigerant <NUM> flowing through the refrigerant flow path <NUM> (<NUM>). Therefore, in the rotating electrical machine <NUM> in which the refrigerant flow path <NUM> (<NUM>) including the first flow path <NUM> (<NUM>) and the second flow path <NUM> (<NUM>) is formed, cooling performance is improved and necessary cooling performance is obtained.

In the rotating electrical machine <NUM> according to the above embodiment and the modifications, the inlet α (γ) and the outlet β (δ) of the refrigerant <NUM> are provided at positions at which the inlet α (γ) and the outlet β (δ) of the refrigerant <NUM> are separated from each other in a circumferential direction of the inner housing <NUM> (<NUM>). For this reason, an effect of improving the cooling performance is particularly remarkable.

In the rotating electrical machine <NUM> according to the embodiment and the modifications, the refrigerant flow path <NUM> (<NUM>) includes a third flow path <NUM> (<NUM>) having a uniform width between the first flow path <NUM> (<NUM>) and the second flow path <NUM> (<NUM>). Since the width of the third flow path <NUM> (<NUM>) is uniform, the velocity reduction and the pressure loss of the refrigerant <NUM> flowing through the refrigerant flow path <NUM> (<NUM>) are reduced. Therefore, since the refrigerant flow path <NUM> (<NUM>) includes the third flow path <NUM> (<NUM>), the required sufficient cooling effect can be easily obtained while satisfying an allowable pressure loss condition.

In the rotating electrical machine <NUM> according to the embodiment and the modifications, the width of the third flow path <NUM> (<NUM>) is narrower than a width of a widest portion of the first flow path <NUM> (<NUM>) and narrower than a width of a widest portion of the second flow path <NUM> (<NUM>). This structure is particularly likely to suppress pressure loss. As a result, the required sufficient cooling effect can be particularly easily obtained while satisfying the allowable pressure loss condition.

In the rotating electrical machine <NUM> according to the embodiment and the modification, when a flow path connecting the inlet α (γ) and the outlet β (δ) with a uniform width determined according to an allowable pressure loss of the refrigerant <NUM> is defined as a reference flow path <NUM>, the first flow path <NUM> (<NUM>) has a shape obtained by expanding the reference flow path <NUM> in a direction of the one end surface <NUM> (<NUM>) of the inner housing <NUM> (<NUM>). The second flow path <NUM> (<NUM>) has a shape obtained by expanding the reference flow path <NUM> in a direction of the other end surface <NUM> (<NUM>) of the inner housing <NUM> (<NUM>). When the reference flow path <NUM> is formed and the reference flow path <NUM> surrounds the inner housing <NUM> (<NUM>), the flow path non-forming portion <NUM> is inevitably formed. In contrast, as described above, the first flow path <NUM> (<NUM>) and the second flow path <NUM> (<NUM>) each have a shape obtained by expanding the reference flow path <NUM> in the directions of the one end surface <NUM> (<NUM>) and the other end surface <NUM> (<NUM>), respectively. For this reason, in the refrigerant flow path <NUM> (<NUM>), a portion of the flow path non-forming portion <NUM> generated when the reference flow path <NUM> is formed becomes the first flow path <NUM> (<NUM>) and the second flow path <NUM> (<NUM>). As a result, the rotating electrical machine <NUM> is more reliably cooled.

In the rotating electrical machine <NUM> according to the embodiment and the modifications, a boundary between the first flow path <NUM> (<NUM>) and the third flow path <NUM> (<NUM>) and a boundary between the second flow path <NUM> (<NUM>) and the third flow path <NUM> (<NUM>) are formed by straight lines along a circumferential direction of the inner housing <NUM> (<NUM>). Accordingly, the third flow path <NUM> (<NUM>) is a flow path generally conforming to the reference flow path <NUM>. As a result, the pressure loss of the refrigerant <NUM> in the third flow path <NUM> (<NUM>) is reduced, and the cooling performance is further enhanced.

In the rotating electrical machine <NUM> according to the embodiment and the modifications, the first flow path <NUM> (<NUM>) is provided in a range extending around the circumferential surface of the inner housing <NUM> (<NUM>) from the inlet α (γ). The second flow path <NUM> (<NUM>) is provided in a range extending around the circumferential surface of the inner housing <NUM> (<NUM>) from the outlet β (δ). A range of one round from the inlet α (γ) and a range of one round from the outlet β (δ) are particularly prone to the generation of the flow path non-forming portion <NUM>. Therefore, when the first flow path <NUM> (<NUM>) is provided in the range of at least one round from the inlet α (γ) and the second flow path <NUM> (<NUM>) is provided in the range of at least one round from the outlet β (δ), the cooling performance of the rotating electrical machine <NUM> is easily improved.

However, the first flow path <NUM> (<NUM>) may be provided beyond the range of one round from the inlet α (γ), and the second flow path <NUM> (<NUM>) may be provided within the range of one round from the outlet β (δ). When there are other circumstances, such as when the third flow path <NUM> (<NUM>) is not provided as shown in <FIG>, the first flow path <NUM> (<NUM>) and/or the second flow path <NUM> (<NUM>) may not be provided in the entire range of one round.

In the rotating electrical machine <NUM> according to the embodiment and the modifications, the inner housing <NUM> (<NUM>) includes the inner housing <NUM> that is a first housing, the inner housing <NUM> that is a second housing, and a coupling pipe <NUM>. The inner housing <NUM> that is the first housing accommodates a stator <NUM> as a first stator and a rotor <NUM> as a first rotor, and has the refrigerant flow path <NUM>. The inner housing <NUM> that is the second housing accommodates a stator <NUM> as a second stator and a rotor <NUM> as a second rotor, and has the refrigerant flow path <NUM>. The coupling pipe <NUM> linearly couples the outlet β of the inner housing <NUM> that is the first housing and the inlet γ of the inner housing <NUM> that is the second housing without waste. For this reason, the rotating electrical machine <NUM> incorporating two motors is configured to be compact while maintaining the cooling performance thereof. Further, the cost of the rotating electrical machine <NUM> is additionally reduced.

In the rotating electrical machine <NUM> according to the embodiment and the modifications, the refrigerant flow path <NUM> of the inner housing <NUM> that is the second housing is formed in a spiral shape that is wound in a reverse direction with respect to the refrigerant flow path <NUM> of the inner housing <NUM> that is the first housing. In this way, when the two refrigerant flow paths <NUM> and <NUM> to be coupled are formed in a spiral shape in which the two refrigerant flow paths <NUM> and <NUM> are wound in opposite directions to each other, the rotating electrical machine <NUM> incorporating two motors is easily configured to be particularly compact while maintaining the cooling performance thereof.

Although the embodiment of the present invention has been described above, configurations described in the embodiment and the modification are only a part of application examples of the present invention, and are not intended to limit the technical scope of the present invention.

For example, the first motor <NUM> may be a power generation motor, and the second motor <NUM> may be a driving motor. Further, both the first motor <NUM> and the second motor <NUM> may be driving motors, and both the first motor <NUM> and the second motor <NUM> may be power generation motors.

In the above embodiment, the refrigerant flow path <NUM> is formed by the grooves <NUM> provided in the outer circumferential surface of the inner pipe <NUM>. Alternatively, the refrigerant flow path <NUM> can be formed by providing similar grooves in the inner circumferential surface of the outer pipe <NUM>. The refrigerant flow path <NUM> may be formed by providing grooves in both the outer circumferential surface of the inner pipe <NUM> and the inner circumferential surface of the outer pipe <NUM>. The same applies to the refrigerant flow path <NUM>.

Claim 1:
A rotating electrical machine (<NUM>) comprising a cylindrical housing (<NUM>) having a flow path (<NUM>,<NUM>) configured to allow a refrigerant (<NUM>) to flow therethrough, an inlet (δ) configured to allow the refrigerant to flow into the flow path (<NUM>,<NUM>), and an outlet (β) configured to allow the refrigerant to flow out of the flow path (<NUM>,<NUM>), the flow path (<NUM>,<NUM>) being formed so as to spirally surround a circumferential surface of the housing (<NUM>), wherein the flow path (<NUM>,<NUM>) includes:
a first flow path (<NUM>,<NUM>) that is formed along one end surface of the housing and formed such that a width along the circumferential surface increases along a flow direction of the refrigerant from the inlet;
a second flow path (<NUM>,<NUM>) that is formed along the other end surface of the housing and formed such that a width along the circumferential surface decreases toward the outlet along the flow direction of the refrigerant; and
a third flow path (<NUM>,<NUM>) having a uniform width between the first flow path and the second flow path, and a width of the third flow path (<NUM>,<NUM>) is narrower than a width of a widest portion of the first flow path (<NUM>,<NUM>) and narrower than a width of a widest portion of the second flow path (<NUM>,<NUM>), wherein the rotating electrical machine (<NUM>) includes:
the cylindrical housing (<NUM>), which is a first housing (<NUM>) that accommodates a first stator (<NUM>) and a first rotor (<NUM>) and has the flow path (<NUM>) ;
a second housing (<NUM>) that accommodates a second stator (<NUM>) and a second rotor (<NUM>) and has the flow path (<NUM>); and
a coupling pipe (<NUM>) that linearly couples the outlet of the first housing (<NUM>) and the inlet of the second housing (<NUM>),
wherein the flow path (<NUM>) of the second housing (<NUM>) is formed in a spiral shape that is wound in a reverse direction with respect to the flow path (<NUM>) of the first housing (<NUM>).