JP7690897B2 - Hybrid system drive unit - Google Patents

Description

This disclosure relates to a drive unit for a hybrid system.

It is known to use an oil-cooled motor as a drive unit for a hybrid system.

Patent Document 1 discloses a clutch and motor housing structure for a hybrid electric vehicle. This is a clutch housing that houses a wet hydraulic clutch for transmitting driving force from the engine to the transmission, and an air breather mounting structure that suppresses pressure increases within the motor housing that houses an oil-cooled driving motor.

JP 2011-126320 A

When air bubbles generated by oil agitation cover the coils and rotor inside the motor chamber, cooling performance is reduced, so a known method is to provide a breather. However, providing a breather increases the number of parts.

The present invention was made to solve these problems, and aims to provide a drive unit for a hybrid system that prevents a decrease in cooling performance caused by air bubbles generated by agitation of the oil while suppressing an increase in the number of parts.

A drive device for a hybrid system according to one aspect of the present invention comprises:
an oil-cooled motor having a rotating shaft to which the output of the engine is transmitted as an output shaft;
a transmission to which power is transmitted from the rotating shaft;
a housing including a partition wall that separates a motor chamber that houses the oil-cooled motor from a transmission chamber that houses the transmission;
having
Oil is stored in the bottom of the housing,
The partition wall has a communication oil passage at a bottom of the housing that communicates with the motor chamber and the transmission chamber.

This disclosure makes it possible to provide a drive unit for a hybrid system that prevents a decrease in cooling performance due to air bubbles generated by agitation of the oil while suppressing an increase in the number of parts.

1 is a cross-sectional view of a hybrid system drive device according to an embodiment of the present invention; 2 is a schematic diagram showing a flow path of an ATF in a hybrid system drive device according to an embodiment of the present invention;

Embodiments of the present disclosure will now be described in detail with reference to the drawings. In each drawing, identical or corresponding elements are denoted by the same reference numerals, and duplicated descriptions will be omitted as necessary for clarity of explanation.

Figure 1 is a cross-sectional view of a hybrid system drive device 1 according to an embodiment. Figure 1 illustrates a drive device for a front-engine, rear-drive hybrid vehicle. The hybrid system drive device 1 has a motor generator (rotating electric machine) MG, a rotating shaft 11 connected to an engine, and an AT (Automatic Transmission) gear 13 connected to the rotating shaft 11. The motor generator may also be simply called a motor. The hybrid system drive device 1 is housed in a housing 10. Specifically, Figure 1 is a view of the housing 10 seen from the side of the vehicle, and the housing 10 has a front motor chamber M, a rear gear chamber G, and a partition wall P that separates the motor chamber M from the gear chamber G. The motor chamber M is also called a motor case. The gear chamber G is also called a gear case, a transmission chamber, or a transmission case.

Although not shown, an engine is disposed in front of the drive unit 1. The engine (not shown) is an internal combustion engine that uses gasoline, diesel, or the like as fuel and converts the reciprocating motion of a piston into the rotational motion of a crankshaft (rotating shaft). The motor chamber M houses an oil-cooled motor generator MG, the output shaft of which is the rotating shaft 11 to which the output of the engine is transmitted. The motor generator MG includes a stator 100 and a rotor 200 housed in the motor chamber M. The stator 100 includes an annular stator core 101 and a stator coil 102 wound around the stator core 101. The rotor 200 includes a rotor core 201 and end plates 202, 203 disposed on both sides of the rotor core 201 in the axial direction. The rotor core 201 is formed by stacking a plurality of electromagnetic steel plates formed into an annular shape by press working, for example. In addition, rotor core 201 has multiple through holes (not shown) that are spaced circumferentially and extend in the axial direction, and a permanent magnet is embedded in each through hole. In motors that generate a lot of heat, such as hybrid motors, an oil-cooled system is generally used in which cooling and lubricating oil is sprayed on the core and coil ends to cool them.

As shown in FIG. 1, a front flange portion 81f having multiple bolt holes is formed on the outer periphery of one end (front end) of the outer shell portion 81 of the motor chamber M of the housing 10, i.e., the open end side. The front flange portion 81f is fastened (fixed) to the engine block of the engine via multiple bolts (not shown) inserted into the corresponding bolt holes. The other end of the outer shell portion 81 protrudes from the end wall 82 on the opposite side to the front flange portion 81f, and a rear flange portion 81r having multiple bolt holes is formed on the outer periphery of the other end (rear end) of the outer shell portion 81. The rear flange portion 81r is fastened (fixed) to the front end of the transmission case (gear chamber G) of the power transmission device via multiple bolts inserted into the corresponding bolt holes.

The motor chamber M of the housing 10 is formed by casting an aluminum alloy and includes a cylindrical outer shell 81 and an end wall (wall) 82 that closes the other end of the outer shell 81. The motor case includes the motor chamber M with one end open and a cover 88 that is fixed to cover the one end. The cover 88 is fixed to the motor chamber M of the housing 10 via a number of bolts. The cover 88 forms an end wall of the motor case that extends radially so as to face the motor generator MG and the clutch K0 on the engine side. The clutch K0 connects the rotating shaft 11a, i.e., the crankshaft of the engine, to the rotating shaft (transmission shaft) 11b, i.e., the rotor 200 of the motor generator MG, and also disconnects the two.

Similarly, the gear chamber G of the housing 10 is formed by casting an aluminum alloy and includes a cylindrical outer shell 91 and an end wall (wall) 92 that closes the other end of the outer shell 91. The gear case includes the gear chamber G with one end open and a cover 98 that is fixed to cover the one end. The cover 98 is fixed to the gear chamber G of the housing 10 via a number of bolts 99. The gear chamber G houses a transmission (AT gear 13 in FIG. 1) to which power from the rotating shaft 11 is transmitted. In this example, the rotating shaft in the motor chamber and the rotating shaft in the gear chamber are the same single shaft. The rotating shafts 11a to 11c are collectively referred to as the rotating shaft 11.

Oil is stored at the bottom of the housing 10. This oil is also called ATF (Automatic Transmission Fluid). Specifically, in the housing 10, an oil pan 110 is formed at the bottom 111 of the motor chamber M, and an oil pan 130 is formed at the bottom 131 of the gear chamber G. In the gear chamber G, the AT gear 13 is configured symmetrically with respect to the rotating shaft 11, and the oil pan 130 is provided below the lower end (dashed line) of the AT gear 13. In addition, an oil pump 140 that circulates oil along the path shown in FIG. 2 is provided adjacent to the rear of the oil pan 130 in the gear chamber G. As a result, at the bottom of the housing 10, the oil pan 110, the communicating oil passage 120, and the oil pan 130 form a liquid layer SL in which oil is stored.

The volume of the oil pan 130 is designed to be larger than the volume of the oil pan 110. That is, the oil pan 130 is designed to be longer than the oil pan 110 in the front-to-rear direction, and also longer in the up-down direction. Furthermore, the bottom end of the oil pan 130 is designed to be lower than the bottom end of the oil pan 110. This allows the oil to flow from the oil pan 110 in the motor chamber M to the oil pan 130 in the transmission chamber G. The upper surface of the liquid layer SL can be designed to be located a predetermined distance H below the bottom end of the AT gear 13.

The oil level in the oil pan 130 may rise or fall due to a rise in the ATF temperature or a change in the vehicle's position while driving. When the ATF oil level at the bottom of the gear chamber G rises and touches the AT gear 13, the oil may be agitated as the AT gear 13 rotates, generating air bubbles (air bubble layer AB in Figure 1). When the ATF oil level then falls, the generated air bubbles reach the motor chamber M and cover the motor coil 102 and rotor 200, which may impede cooling performance (heat dissipation).

Therefore, in this disclosure, in order to solve these problems, the motor chamber M and the gear chamber G are arranged separately, and an oil communication passage 120 is provided at the bottom of the partition wall P that separates them to prevent air bubbles from entering the motor chamber M. The communication passage 120 is arranged at a position slightly higher than the bottom 111 of the oil pan 110 and the bottom 131 of the oil pan 130, and is provided to communicate the oil pan 110 and the oil pan 130. The length of the communication passage 120 in the front-rear direction of the vehicle may be a predetermined distance or more. Specifically, the oil communication passage 120 is provided a predetermined distance D below the lower end of the AT gear 13. This predetermined distance can be set arbitrarily so that air bubbles generated by the rotation of the AT gear 13 are unlikely to reach the motor chamber M or do not reach it at all.

In some embodiments, the housing 10 may be designed so that the ATF oil level is above the communicating oil passage 120. This allows the ATF to be filled in the communicating oil passage 120, thereby minimizing the backflow of air bubbles into the motor chamber.

When the vehicle is tilted to the left while driving, the air bubble layer AB, where air bubbles can form in the transmission chamber, is located above the communicating oil passage 120, preventing air bubbles from flowing into the motor chamber. On the other hand, when the vehicle is tilted to the right while driving, the ATF is biased toward the transmission chamber, preventing air bubbles from flowing into the motor chamber.

FIG. 2 is a schematic diagram showing a flow path of the ATF in the hybrid system drive device according to the embodiment.
Oil stored in an oil pan 130 in the AT section (transmission compartment) is sent by an oil pump 140 through an oil passage to a heat exchanger 150 in the vehicle's radiator. The oil cooled by the heat exchanger 150 then passes through an oil passage in the axial center of the rotating shaft 11 and reaches the motor compartment M. As the rotating shaft 11 rotates, the oil is scattered over the motor MG, absorbing heat from the motor MG, and is then stored in the oil pan 110 in the motor compartment M.

Similarly, the oil cooled by the heat exchanger 150 passes through an oil passage in the axial center of the rotating shaft 11 and reaches the transmission chamber G. As the rotating shaft 11 rotates, the oil is dispersed over the AT gear 13, absorbing heat from the AT gear 13, and then accumulates in the oil pan 130 in the transmission chamber G.

The oil communication passage 120 described above connects the oil pan 110 of the motor chamber M to the oil pan 130 of the transmission chamber G. As shown in FIG. 2, the oil is designed to flow from the oil pan 110 of the motor chamber M to the oil pan 130 of the transmission chamber G, preventing air bubbles generated on the oil pan 130 side by the AT gear 13 of the transmission chamber G from flowing back into the motor chamber.

The oil stored in the oil pans 110 and 130 is sent again by the oil pump 140 to the heat exchanger 150 and the radiator. The heat exchanger 150 exchanges heat between the oil and the outside. The hot oil that absorbs heat from the motor and gears is cooled by the heat exchanger 150.

The hybrid system drive device according to the embodiment described above can prevent a decrease in cooling performance caused by air bubbles generated by agitating the oil while suppressing an increase in the number of parts such as breathers.

The present invention is not limited to the above embodiment, and can be modified as appropriate without departing from the spirit and scope of the invention.

M Motor room P Partition G Gear room (transmission room)
MG Motor generator K0 Clutch AB Air bubble layer SL Liquid layer 1 Drive device for hybrid system 10 Housing 11 (11a to 11c) Rotating shaft 13 AT gear 81 Outer shell portion 91 Outer shell portion 100 Stator 110 Oil pan 111 Bottom portion 120 Connecting oil passage 130 Oil pan 131 Bottom portion 140 Oil pump 150 Heat exchanger 200 Rotor

Claims (5)

an oil-cooled motor having a rotating shaft to which the output of the engine is transmitted as an output shaft;
a transmission to which power is transmitted from the rotating shaft;
a housing including a partition wall that separates a motor chamber that houses the oil-cooled motor from a transmission chamber that houses the transmission;
having
An oil pan for the motor chamber and an oil pan for the transmission chamber are provided at the bottom of the housing,
the partition wall portion includes a communication oil passage at a bottom portion of the housing, the communication oil passage connecting the motor chamber and the transmission chamber,
the communication oil passage is provided a predetermined distance below a lower end of the transmission so that air bubbles generated in the transmission chamber do not flow into the motor chamber,
At the bottom of the housing, a liquid layer in which oil is stored is formed in the oil pan of the motor chamber, the communicating oil passage, and the oil pan of the transmission chamber, and an upper surface of the liquid layer is provided a predetermined distance below a lower end of the transmission.
Drive unit for hybrid system. 2. The drive device for a hybrid system according to claim 1, wherein oil stored in the oil pan of the transmission chamber is sent by an oil pump through an oil passage to a heat exchanger of a radiator of a vehicle, and the oil cooled in the heat exchanger further passes through an oil passage within the axis of the rotating shaft to reach the motor chamber, and the oil is scattered toward the oil-cooled motor as the rotating shaft rotates, absorbing heat from the oil-cooled motor, and then is stored in the oil pan of the motor chamber . The communication oil passage is configured to be filled with oil,
3. The drive device for a hybrid system according to claim 2, wherein the oil cooled in the heat exchanger of the radiator of the vehicle further passes through an oil passage within the axis of the rotating shaft to reach the transmission chamber, and the oil is dispersed toward the transmission as the rotating shaft rotates, removing heat from the transmission, and then stored in the oil pan of the transmission chamber . The hybrid system drive device according to any one of claims 1 to 3, wherein the volume of the oil pan formed at the bottom of the transmission chamber is configured to be larger than the volume of the oil pan formed at the bottom of the motor chamber. The drive unit for a hybrid system according to any one of claims 1 to 4, wherein the drive unit is for a front-engine, rear-drive automobile.

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