JP7157921B2 - Vehicle electric motor cooling system - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric motor cooling system for a vehicle, and more particularly, a vehicle including a first cooling mechanism for an inverter in which a first refrigerant circulates and a second cooling mechanism for an electric motor in which a second refrigerant less than the first refrigerant circulates. relates to a motor cooling system.

BACKGROUND ART Conventionally, a hybrid vehicle is known that includes a cooling mechanism for cooling an engine, a cooling mechanism for cooling an electric motor, and a cooling mechanism for cooling an inverter.
In such a hybrid vehicle, a cooling circuit comprising pump means for moving a cooling medium such as water, a so-called refrigerant, a passage through which the refrigerant flows, and a heat exchanger for exchanging heat with the refrigerant is a cooling mechanism. set independently for each.

The cooling system of Patent Document 1 includes a first cooling passage through which a first cooling liquid as a refrigerant flows, and a motor cooling means for supplying the first cooling liquid in the first cooling passage to the electric motor to cool the electric motor; a motor cooling means including a second cooling passage through which a second cooling liquid flows and supplying the second cooling liquid in the second cooling passage to the inverter to cool the inverter; and an inverter-side heat exchanger. A side heat exchanger exchanges heat between the first and second coolants.
This eliminates the radiator from the motor cooling means.

Generally, in an FR (front engine rear drive) type hybrid vehicle, the engine is arranged in the engine room in the front part of the vehicle body, and a drive motor consisting of an electric motor is connected to the rear end of the engine. A transmission is connected to the rear end portion.
The driving force of the engine or the driving motor, or the driving force of the engine and the driving motor is selectively input to the transmission through the power transmission shaft.
The driving force input to the transmission is transmitted to the rear differential gear via the propeller shaft to drive the rear wheels.

Patent No. 6156186

The cooling system of Patent Document 1 attempts to reduce the number of parts by omitting the heat exchanger for cooling the first coolant from the motor cooling means.
However, if the clutch that engages and releases the engine and the transmission is arranged on the inner peripheral side of the electric motor, only the electric motor exists in the area between the engine and the transmission. It may become difficult to secure
In particular, in an FR hybrid vehicle, it is necessary to dispose the cooling mechanism in a range defined by the axial dimension of the electric motor, and the layout of the cooling mechanism for the electric motor is not easy.
That is, it is necessary to further reduce the number of parts, simplify the configuration, and reduce the size.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric motor cooling system for a vehicle, etc., which can reduce the number of parts, simplify the configuration, and reduce the size.

A motor cooling system for a vehicle according to claim 1 includes a first cooling mechanism for an inverter in which a first refrigerant circulates, and a second cooling mechanism for an electric motor in which a second refrigerant having a capacity smaller than that of the first refrigerant circulates. In a vehicle electric motor cooling system comprising: A second passage through which the second refrigerant flows, and a second impeller means disposed in the middle of the second passage and driven by the flow force of the first refrigerant to drive and circulate the second refrigerant are provided. It is characterized by

In this vehicle electric motor cooling system, the first cooling mechanism is provided with the pump means for driving and circulating the first coolant and the first passage through which the first coolant flows. Accordingly, heat exchange efficiency can be increased, and the inverter can be efficiently cooled. The second cooling mechanism includes a second passage through which the second refrigerant flows, and a second passage disposed in the middle of the second passage and driven by the flow force of the first refrigerant to drive and circulate the second refrigerant. Since the two impeller means are provided, the second refrigerant can be moved using the flow force of the first refrigerant, and the pump means dedicated to the second refrigerant that can move the second refrigerant from the second cooling mechanism is omitted. be able to.

According to a second aspect of the invention, in the first aspect of the invention, a first impeller means driven to rotate by the circulating first refrigerant is provided in the middle of the first passage, and the first impeller means and the first impeller means are provided. It is characterized in that the two impeller means are configured to be independently rotatable and are connected by a magnetic coupling so as to be synchronously rotatable.
According to this configuration, the flow force of the first refrigerant can be converted into the driving force of the second refrigerant with a simple configuration without impairing the sealing performance between the first passage and the second passage.

The invention of claim 3 is the invention of claim 1 or 2, wherein the first cooling mechanism has a heat exchanger capable of exchanging heat with outside air in the middle of the first passage, It is characterized in that a heat exchange mechanism capable of exchanging heat between the first refrigerant and the second refrigerant is provided at a portion where the two passages are brought close to each other.
According to this configuration, the second refrigerant can be heat-exchanged with the outside air through the first refrigerant, which is the heat exchange target of the heat exchanger.

The invention of claim 4 is the invention of any one of claims 1 to 3, wherein the electric motor is arranged adjacent to a stator, a rotor disposed on the inner peripheral side of the stator, and a radially outer side of the stator. a ring-shaped stator cooling chamber formed into which the first coolant can be introduced; and a ring-shaped rotor cooling chamber formed adjacent to at least one axial end side of the rotor and into which the second coolant can be introduced; A part of the first passage constitutes the stator cooling chamber, and a part of the second passage constitutes the rotor cooling chamber .
According to this configuration, both cooling performance and compactness can be achieved.

The invention of claim 5 is characterized in that, in the invention of any one of claims 1 to 4, the inverter is mounted above the electric motor.
According to this configuration, further miniaturization can be achieved by shortening the first passage.

According to the vehicle electric motor cooling system of the present invention, the flow force of the first refrigerant is used to move the second refrigerant, thereby reducing the number of parts, simplifying the configuration, and reducing the size.

1 is a plan view of a front vehicle body of a vehicle according to Embodiment 1; FIG. It is a side view of a front vehicle body. 1 is a schematic system diagram of a cooling system; FIG. FIG. 4 is a cross-sectional view of the drive motor taken along a plane perpendicular to the rotor axis; FIG. 3 is a cross-sectional view of the drive motor taken along a plane parallel to the rotor axis; FIG. 4 is an explanatory diagram of first and second cooling mechanisms; It is explanatory drawing of a 1st, 2nd impeller.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on drawing. The following description of preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its applications or uses.

Embodiment 1 of the present invention will be described below with reference to FIGS. 1 to 7. FIG.
A vehicle V of this embodiment is a hybrid vehicle on which a cooling system S is installed.
As shown in FIGS. 1 and 2, this vehicle V is equipped with a multi-cylinder engine 2, which is an internal combustion engine, in the front part of the vehicle body, and has an FR engine that drives a pair of left and right rear wheels (not shown) as main drive wheels. (Front engine rear drive) car. In addition, the rear wheels of the main drive wheels are also driven by a drive motor 1 (electric motor) instead of the engine 2, and a pair of left and right front wheels (not shown), which are auxiliary drive wheels, are driven by an auxiliary drive motor (not shown). It is driven in a predetermined operating range.
The engine 2 and the drive motor 1 are connected so as to be disengaged through a clutch 13, which will be described later.

First, before describing the cooling system S, the premise structure of the vehicle V of this embodiment will be described.
As shown in FIGS. 1 and 2, a vehicle V includes a pair of left and right front side frames 3 extending forward from a dash panel (not shown), and a pair of front side frames 3 outside and above the pair of front side frames 3 in the vehicle width direction. A pair of left and right wheel apron reinforcements 4 having a closed cross section are provided to support the suspension towers 5 in cooperation with the pair of front side frames 3 .
A floor panel (not shown) connected to the rear end of the dash panel is formed with a tunnel portion that protrudes into the vehicle interior and extends in the front-rear direction at the center portion in the vehicle width direction.
Hereinafter, in the drawings, the direction of arrow F is defined as the forward direction, the direction of arrow L is defined as the left direction, and the direction of arrow U is defined as the upward direction.

The pair of front side frames 3 supports the engine 2 vertically (the direction of cylinder arrangement is the longitudinal direction) via two pairs of front and rear engine mounts (not shown).
The engine 2 is configured as a flywheelless engine without a flywheel, and drives rear wheels via a power transmission mechanism.
The main components of the power transmission mechanism are a propeller shaft (not shown), a clutch (not shown), and a transmission 6 as a stepped transmission connected to the rear wheels via an axle (not shown). .

The drive motor 1 is composed of, for example, a 25 kW permanent magnet synchronous motor (PM motor) driven by 48 V, and a water-cooled inverter 7 that converts the current of a 48 V battery (for example, a 3.5 kWh lithium-ion battery or the like). AC current is supplied from
The drive motor 1 is connected in series with the engine 2 , and the drive power generated by the drive motor 1 is transmitted to the rear wheels via the power transmission mechanism in the same manner as the drive power of the engine 2 .
The auxiliary drive motor is composed of, for example, a 17 kW three-phase induction motor (SR motor) driven by 120 V, and supplied with alternating current from an inverter (not shown) that converts the current of a capacitor (not shown).

Next, the cooling system S will be explained.
As shown in FIG. 3, the cooling system S includes a first cooling mechanism C1 including the stator 12 of the drive motor 1 and the inverter 7, a second cooling mechanism C2 including the rotor 11 of the drive motor 1, A third cooling mechanism C3 including the clutch 13 and the transmission 6, a heat exchange section M (heat exchange mechanism), a flow conversion section T, and the like are provided.

Here, the drive motor 1 will be described.
As shown in FIGS. 4 and 5, the drive motor 1 mainly includes a motor shaft 1a, a rotor 11, a stator 12, a clutch 13, and a cylindrical housing 14 for accommodating these members. element.
An engine shaft 2a and a motor shaft 1a extending in the front-rear direction are inserted through the housing 14, and these shafts 1a, 2a are rotatably supported via bearings.
The engine shaft 2 a is connected to the engine 2 and rotates integrally with the output shaft of the engine 2 . The engine shaft 2a and the motor shaft 1a are spaced apart in the axial direction, and are configured such that their connection state can be changed by a clutch 13. As shown in FIG.

The clutch 13 has clutch discs that rotate integrally with the engine shaft 2a and clutch plates that rotate integrally with the motor shaft 1a. By moving apart, the connection state is changed. As a result, the clutch 13 is put into an engaged state in which the shafts 1a and 2a are engaged and rotate together, and a disengaged state in which the shafts 1a and 2a are disengaged and no rotational force is transmitted between the shafts 1a and 2a. state is changed.

Further, the clutch 13 has a clutch cooling portion 13a.
The clutch cooling portion 13a supplies ATF (Automatic Transmission Fluid) of the transmission 6 to through passages formed in the vicinity of the clutch discs and the clutch plates, thereby performing heat exchange between the ATF and the clutch discs and the clutch plates from the inside. By injecting the ATF toward the clutch discs and clutch plates, heat exchange between the ATF and the clutch discs and clutch plates is achieved from the outside.
This allows the lubricating oil of the transmission 6 to function as a coolant of the clutch 13 .

As shown in FIGS. 4 and 5, the rotor 11 is arranged radially outside the clutch 13 and has magnets inside. The rotor 11 is fixed to the motor shaft 1a and is configured to rotate integrally with the motor shaft 1a.
A pair of front and rear ring-shaped rotor cooling chambers 11 a (see FIG. 6 ) are provided adjacent to the rotor 11 on one axial side (front side) and the other axial side (rear side) of the rotor 11 . . The rotor cooling chamber 11a has a coolant introduction portion formed at its upper end portion and a coolant discharge portion formed at its lower end portion.

The stator 12 has a stator core wound with a coil. The stator 12 is arranged radially outward of the rotor 11 with a small gap and fixed to the housing 14 . A ring-shaped stator cooling chamber 12 a (see FIG. 6 ) is provided radially outside the stator 12 so as to be adjacent to the stator 12 . The stator cooling chamber 12a has a coolant introduction portion formed at its upper end portion and a coolant discharge portion formed at its lower end portion.

Returning to the description of the cooling system S.
As shown in FIG. 3, the first to third cooling mechanisms C1 to C3 are configured as closed refrigerant paths so that the respective refrigerants can circulate.
The first cooling mechanism C1 includes a first passage 21 through which a first refrigerant (for example, water) at an intermediate temperature (for example, 70° C.) flows, a radiator 22 provided in the middle of the first passage 21, and an electric It has a pump 23 (pump means), an inverter 7, a stator 12, and the like.
Therefore, the stator cooling chamber 12 a provided in the stator 12 forms part of the first passage 21 .

The second cooling mechanism C2 includes a second passage 31 through which a high-temperature (eg, 120° C.) second refrigerant (eg, cooling oil) flows. Therefore, the rotor cooling chamber 11 a provided in the rotor 11 forms part of the second passage 31 . Since the second cooling mechanism C2 has a smaller circuit scale than the first cooling mechanism C1, the capacity of the second refrigerant circulating in the second cooling mechanism C2 (for example, about 2 liters) is limited to the first cooling mechanism C1. The capacity is much smaller than the capacity of the circulating first refrigerant (for example, about 10 liters).
The third cooling mechanism C3 has a third passage 41 through which the second refrigerant (lubricating oil for the transmission 6) flows. Therefore, the clutch cooling portion 13 a formed by a through passage or the like formed in the vicinity of the clutch disk and the clutch plate of the clutch 13 constitutes a part of the third passage 41 .

As shown in FIGS. 3, 4, and 6, the heat exchange portion M is provided in a region where the middle portion of the first passage 21 and the middle portion of the second passage 31 are close to each other.
Specifically, as shown in FIG. 6, a volumetric chamber 25 capable of storing the first refrigerant is provided midway downstream of the lead-out portion of the first passage 21, and a volume chamber 25 downstream of the lead-out portion of the second passage 31 is provided. A volumetric chamber 35 capable of storing the second refrigerant is provided in the middle, and the wall surfaces of both volumetric chambers 25, 35 are arranged close to each other so that heat can be exchanged.

As shown in FIGS. 3 to 7, the fluid force conversion section T is provided in a downstream region of the heat exchange section M where the middle portion of the first passage 21 and the middle portion of the second passage 31 are close to each other.
Specifically, as shown in FIGS. 5 and 7, the first passage 21 and the second passage 31 are integrally formed in the region where the fluid force converting portion T is formed.
The flow force converting section T includes a first turbine 26 (first impeller means) and a second turbine 36 (second impeller means) which is smaller than the first turbine 26 and can rotate independently of the first turbine 26. ).

The first turbine 26 is rotatably supported by a plurality of fins, a boundary wall portion between the first passage 21 and the second passage 31, and a partition wall portion opposed thereto, and extends back and forth. It is composed of a rotating shaft 26a and a plurality of magnets 26n and 26s attached alternately in the circumferential direction around the rotating shaft 26a on a surface facing the boundary wall between the first passage 21 and the second passage 31. . The magnet 26n has N-pole magnetism, and the magnet 26s has S-pole magnetism.

As shown in FIG. 7, the second turbine 36 includes a plurality of fins, a rotating shaft 36a, and a surface portion facing the boundary wall portion between the first passage 21 and the second passage 31 and rotating around the rotating shaft 36a. It consists of a plurality of magnets 36n and 36s mounted in alternating directions.
The rotating shaft 36a is arranged on an extension line of the rotating shaft 26a with the boundary wall portion between the first passage 21 and the second passage 31 interposed therebetween.
The plurality of magnets 36n and 36s are arranged so as to face the plurality of magnets 26n and 26s with the boundary wall portion between the first passage 21 and the second passage 31 interposed therebetween.
The magnet 36n has N-pole magnetism, and the magnet 36s has S-pole magnetism.

The boundary wall width between the rotating shaft 26a and the rotating shaft 36a is formed larger than the boundary wall width between the magnets 26n, 26s and the magnets 36n, 36s. The boundary wall width of the portion where the first and second turbines 26 and 36 do not exist is formed larger than the boundary wall width.
This constitutes a magnetic coupling. Specifically, when the first refrigerant having a large circulation capacity flows due to the operation of the electric pump 23, the large first turbine 26 rotates around the rotating shaft 26a and the plurality of magnets 26n and 26s rotate around the rotating shaft 26a. Rotate. Rotation of the plurality of magnets 26n and 26s about the rotation axis 26a induces synchronous rotation of the plurality of magnets 36n and 36s, which are magnetically coupled to the plurality of magnets 26n and 26s, causing the small second turbine 36 to rotate. do.

Next, the operation and effects of the cooling system S will be described.
In this cooling system S, the first cooling mechanism C1 is provided with the electric pump 23 that drives and circulates the first refrigerant, and the first passage 21 through which the first refrigerant flows. The heat exchange efficiency can be increased, and the inverter 7 can be efficiently cooled.
In the second cooling mechanism C2, a second passage 31 through which the second refrigerant flows, and a second passage 31 disposed in the middle of the second passage 31 and driven by the flow force of the first refrigerant to drive and circulate the second refrigerant. Since the turbine 36 is provided, the flow force of the first refrigerant can be used to move the second refrigerant, and pump means dedicated to the second refrigerant that can move the second refrigerant from the second cooling mechanism C2 can be omitted. can be done.

A first turbine 26 that is rotationally driven by the circulating first refrigerant is provided in the middle of the first passage 21, and the first turbine 26 and the second turbine 36 are configured to be independently rotatable and coupled with a magnetic coupling. , the flow force of the first refrigerant by the electric pump 23 can be combined with the driving force of the second refrigerant with a simple configuration without impairing the sealing performance between the first passage 21 and the second passage 31. can be converted to

The first cooling mechanism C1 has a radiator 22 capable of exchanging heat with the outside air in the middle of the first passage 21, and a first refrigerant and a second refrigerant are provided at a portion where the first passage 21 and the second passage 31 are brought close to each other. Since the heat exchange portion M is provided, the second refrigerant can be heat-exchanged with the outside air via the first refrigerant, which is the object of heat exchange by the radiator 22 .

A drive motor 1 includes a stator 12 and a rotor 11 arranged on the inner peripheral side of the stator 12 , a portion of a first passage 21 is arranged adjacent to the radially outer side of the stator 12 , and a portion of a second passage 31 . Since the portion is arranged adjacent to at least one end side of the rotor 11 in the axial direction, both cooling performance and compactness can be achieved.

Since the inverter 7 is mounted above the drive motor 1, it can be arranged close to the engine mount that supports the engine 2, and the first passage 21 can be shortened to achieve further miniaturization.

Next, a modified example in which the above embodiment is partially modified will be described.
1) In the above embodiment, the first cooling mechanism in which the inverter and the stator are arranged in series and the second cooling mechanism having the rotor are provided. A second cooling mechanism having either one of the rotors, or a second cooling mechanism having a stator and a rotor may be configured.

2) In the above embodiment, an example in which the first and second passages are integrally formed in the flow force converting section has been described. can be configured independently through a minute gap.
In addition, in the above-described embodiment, an example in which the fluid force conversion unit and the heat exchange unit are arranged under the drive motor has been described, but the fluid force conversion unit and the heat exchange unit are arranged above the drive motor Also good.

3) In the above embodiment, an example of an axial gap type motor was explained, but a radial gap type motor may be used.

4) In addition, without departing from the spirit of the present invention, a person skilled in the art can implement the above-described embodiment in a form in which various modifications are added or in a form in which each embodiment is combined. Any modifications are also included.

1 Drive Motor 7 Inverter 11 Rotor 12 Stator 21 First Passage 22 Radiator 23 Electric Pump 26 First Turbine 31 Second Passage 36 Second Turbine S Cooling System C1 to C3 First to Third Cooling Mechanism T Fluid Force Conversion Part M Heat Exchange part V Vehicle

Claims (5)

An electric motor cooling system for a vehicle comprising a first cooling mechanism for an inverter through which a first refrigerant circulates and a second cooling mechanism for an electric motor through which a second refrigerant having a capacity smaller than that of the first refrigerant circulates,
The first cooling mechanism is provided with pump means for driving and circulating the first refrigerant, and a first passage through which the first refrigerant flows,
The second cooling mechanism includes a second passage through which the second refrigerant flows, and a second passage disposed in the middle of the second passage and driven by the flow force of the first refrigerant to drive and circulate the second refrigerant. 2. An electric motor cooling system for a vehicle, characterized in that it is provided with two impeller means. A first impeller means that is rotationally driven by the circulating first refrigerant is provided in the middle of the first passage,
2. The electric motor for a vehicle according to claim 1, wherein said first impeller means and said second impeller means are independently rotatable and are connected to each other by a magnetic coupling so as to be synchronously rotatable. cooling system. The first cooling mechanism has a heat exchanger capable of exchanging heat with outside air in the middle of the first passage,
3. The vehicle according to claim 1, wherein a heat exchange mechanism capable of exchanging heat between the first refrigerant and the second refrigerant is provided at a portion where the first passage and the second passage are brought close to each other. Motor cooling system. The electric motor includes a stator, a rotor arranged on the inner peripheral side of the stator, a ring-shaped stator cooling chamber formed so as to be adjacent to the radially outer side of the stator and into which the first coolant can be introduced, and the rotor. a ring-shaped rotor cooling chamber formed adjacent to at least one end side in the axial direction and into which the second coolant can be introduced ;
A part of the first passage forms the stator cooling chamber, and a part of the second passage forms the rotor cooling chamber . Vehicle electric motor cooling system. 5. The electric motor cooling system for a vehicle according to claim 1, wherein said inverter is mounted above said electric motor.

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