JP4876568B2 - Cooling structure of motor generator for hybrid vehicles - Google Patents

Description

  In the present invention, an engine, a motor generator, and a transmission are connected in series to form a hybrid drive system, a motor generator is built in a transmission case of the transmission, and a cooling medium path is set at an outer peripheral position of the motor generator. The present invention relates to a cooling structure and an assembling method of a motor generator for a hybrid vehicle.

The cooling structure of a motor generator for a hybrid vehicle incorporating a motor in the transmission is provided with a cooling water jacket on the outer periphery of the transmission case, and an outer end opening of the water jacket is provided integrally with the front cover of the transmission case. It is configured to be closed by a plug (see, for example, Patent Document 1).
JP 2003-74679 A

However, the conventional cooling structure and method for assembling a motor generator for a hybrid vehicle have the following problems because a part of the case has a hollow structure and is water-cooled to allow water to pass therethrough. .
Problem 1
In manufacturing, since the molding cannot be performed unless the minimum R of the casting core in the hollow portion of the case is R6 (radius 6 mm) or more, the thickness (radial direction) of the hollow portion becomes thicker than necessary, and the outer diameter of the case increases.
Problem 2
Since the case thickness of the hollow portion is required to some extent in terms of strength, the case outer diameter is increased.
Problem 3
In manufacturing, the contact area of the water jacket cannot be made large (the structure and size of the core are limited), so that a certain amount of water flow is required to ensure cooling efficiency.
Problem 4
Since the hollow part of the case is formed by casting using a core or insert, productivity and yield are poor.

  The present invention has been made by paying attention to the above-mentioned problems, and it is possible to improve the productivity and yield of the case, cool the motor generator with high efficiency while improving the degree of layout freedom and increasing the size of the motor generator. It is an object of the present invention to provide a cooling structure and an assembling method for a hybrid vehicle motor generator.

In order to achieve the above object, in the present invention, an engine, a motor generator, and a transmission are connected in series to form a hybrid drive system, and the motor generator is built in the transmission case of the transmission. In the cooling structure of the motor generator for a hybrid vehicle in which the cooling medium path is set at the outer peripheral position of
The inner surface of the transmission case has a cylindrical shape,
In addition to the transmission case, a motor generator case having a cylindrical outer surface with an outer diameter slightly smaller than the inner diameter of the transmission case is added to the motor generator,
The cooling medium path is formed with an annular cooling groove on at least one of an inner surface of the transmission case and an outer surface of the motor generator case, and the transmission case and the motor generator case are formed in a double cylindrical shape. And set by sealing both ends of the cooling groove with the first annular seal and the second annular seal ,
A partition plate is provided in the cooling medium path at one of all the outer peripheral positions of the stator of the motor generator, a cooling medium inlet port is provided at the first end, and a cooling medium outlet is provided at the second end across the partition plate. A port,
The partition plate is a non-rotating key that prevents the motor generator case from rotating when the motor generator case is fitted to the transmission case .

Therefore, in the cooling structure for a hybrid vehicle motor generator of the present invention, an annular cooling groove is formed on at least one of the inner surface of the transmission case and the outer surface of the motor generator case. The transmission case and the motor generator case are fitted in a double cylindrical shape, and both ends sandwiching the cooling groove at the same time as the fitting are sealed by the first annular seal and the second annular seal. As described above, the gap space formed between the transmission case and the motor generator case by the cooling groove sealed at both ends is set as the cooling medium path at the outer peripheral position of the motor generator.
That is, when setting the cooling medium path, the case mold does not require a core or nest, and the productivity and yield of the case are improved. When setting the cooling medium path, it is not necessary to increase the radial thickness more than necessary as in the case of casting using a core, and the outer diameter of the transmission case can be made smaller than before, thereby increasing the degree of freedom in layout. improves. Further, when the outer diameter of the transmission case is set to the same diameter as that of the conventional case, the case thickness in which the cooling medium path is set can be reduced, so that the motor generator size can be increased accordingly. Furthermore, the cooling medium path can be arranged on the entire outer periphery of the motor generator, and the thickness of the case in the radial direction through the cooling groove can be made thinner than in the case of casting using a core. Therefore, the cooling medium with a wide contact area effectively removes heat from the motor generator, and the motor generator can be cooled with high efficiency.
As a result, the productivity and yield of the case can be improved, and the motor generator can be cooled with high efficiency while improving the degree of freedom in layout and increasing the size of the motor generator.

  BEST MODE FOR CARRYING OUT THE INVENTION A best mode for realizing a cooling structure and an assembling method for a motor generator for a hybrid vehicle according to the present invention will be described below based on Example 1 and Example 2 shown in the drawings.

First, the configuration will be described.
[Configuration of drive system and control system of hybrid vehicle]
FIG. 1 is an overall system diagram showing a rear-wheel drive hybrid vehicle to which the motor generator cooling structure and assembly method of the first embodiment are applied.
As shown in FIG. 1, the drive system of the hybrid vehicle in the first embodiment includes an engine E, a flywheel FW, a first clutch CL1, a motor generator MG, a second clutch CL2, and an automatic transmission AT (speed change). Machine), a propeller shaft PS, a differential DF, a left drive shaft DSL, a right drive shaft DSR, a left rear wheel RL (drive wheel), and a right rear wheel RR (drive wheel). Note that FL is the left front wheel and FR is the right front wheel.

  The engine E is a gasoline engine or a diesel engine, and the opening degree of a throttle valve and the like are controlled based on a control command from an engine controller 1 described later. The engine output shaft is provided with a flywheel FW.

  The first clutch CL1 is a clutch interposed between the engine E and the motor generator MG, and is generated by the first clutch hydraulic unit 6 based on a control command from the first clutch controller 5 described later. The tightening / release including slip fastening and slip opening is controlled by the control hydraulic pressure.

  The motor generator MG includes a first motor shaft 30 (motor shaft), a rotor 31 in which a permanent magnet (not shown) is embedded, and a stator 32 in which a coil 32b is wound around a laminated steel plate 32a. (See FIG. 2), and is controlled by applying a three-phase alternating current generated by the inverter 3 based on a control command from the motor controller 2 described later. The motor generator MG can operate as an electric motor that is driven to rotate by receiving power supplied from the battery 4 (hereinafter, this state is referred to as “power running”), or when the rotor is rotated by an external force. Can function as a generator that generates electromotive force at both ends of the stator coil to charge the battery 4 (hereinafter, this operation state is referred to as “regeneration”). Note that the rotor of the motor generator MG is connected to the input shaft of the automatic transmission AT via the damper 33.

  The second clutch CL2 is a clutch interposed between the motor generator MG and the left and right rear wheels RL and RR. The second clutch CL2 is operated by the second clutch hydraulic unit 8 based on a control command from an AT controller 7 described later. The generated and controlled hydraulic pressure controls the fastening and opening including slip fastening and slip opening.

  The automatic transmission AT is a transmission that automatically switches stepped gears such as 5 forward speeds, 1 reverse speed, etc. according to vehicle speed, accelerator opening, etc., and the second clutch CL2 is a new dedicated clutch. The clutch selected appropriately is used among the plurality of clutches that are engaged at each gear of the automatic transmission AT. The output shaft of the automatic transmission AT is connected to the left and right rear wheels RL and RR via a propeller shaft PS, a differential DF, a left drive shaft DSL, and a right drive shaft DSR.

  As the first clutch CL1 and the second clutch CL2, for example, a wet multi-plate clutch that can continuously control the oil flow rate and hydraulic pressure with a proportional solenoid may be used. This hybrid drive system has two operation modes according to the engagement / disengagement state of the first clutch CL1, and in the disengagement state of the first clutch CL1, the electric vehicle travel mode (hereinafter referred to as the electric vehicle travel mode) travels only with the power of the motor generator MG. In the engaged state of the first clutch CL1, the hybrid vehicle travel mode (hereinafter abbreviated as "HEV mode") that travels with the power of the engine E and the motor generator MG is employed. is there.

Next, the control system of the hybrid vehicle will be described.
As shown in FIG. 1, the hybrid vehicle control system according to the first embodiment includes an engine controller 1, a motor controller 2, an inverter 3, a battery 4, a first clutch controller 5, and a first clutch hydraulic unit 6. The AT controller 7, the second clutch hydraulic unit 8, the brake controller 9, and the integrated controller 10 are configured. The engine controller 1, the motor controller 2, the first clutch controller 5, the AT controller 7, the brake controller 9, and the integrated controller 10 are connected via a CAN communication line 11 that can exchange information with each other. ing.

  The engine controller 1 inputs engine speed information from the engine speed sensor 12, and in response to a target engine torque command or the like from the integrated controller 10, a command for controlling the engine operating point (Ne, Te) is, for example, Output to the throttle valve actuator (not shown). Information on the engine speed Ne is supplied to the integrated controller 10 via the CAN communication line 11.

  The motor controller 2 inputs information from the resolver 13 that detects the rotor rotational position of the motor generator MG, and responds to a target motor generator torque command from the integrated controller 10 to the motor operating point (Nm, Tm) of the motor generator MG. ) Is output to the inverter 3. The motor controller 2 monitors the battery SOC indicating the state of charge of the battery 4, and the battery SOC information is used as control information for the motor generator MG and supplied to the integrated controller 10 via the CAN communication line 11. To do.

  The first clutch controller 5 inputs sensor information from the first clutch hydraulic pressure sensor 14 and the first clutch stroke sensor 15, and engages / releases the first clutch CL 1 in accordance with a first clutch control command from the integrated controller 10. Is output to the first clutch hydraulic unit 6. Information on the first clutch stroke C1S is supplied to the integrated controller 10 via the CAN communication line 11.

  The AT controller 7 inputs sensor information from the accelerator opening sensor 16, the vehicle speed sensor 17, and the second clutch hydraulic pressure sensor 18, and in response to the second clutch control command from the integrated controller 10, A command for controlling opening is output to the second clutch hydraulic unit 8 in the AT hydraulic control valve. Information about the accelerator opening AP and the vehicle speed VSP is supplied to the integrated controller 10 via the CAN communication line 11.

  The brake controller 9 inputs sensor information from a wheel speed sensor 19 and a brake stroke sensor 20 that detect the wheel speeds of the four wheels. For example, when the brake is depressed, the required braking force is obtained from the brake stroke BS. When the regenerative braking force alone is insufficient, the regenerative cooperative brake control is performed based on the regenerative cooperative control command from the integrated controller 10 so that the shortage is supplemented by the mechanical braking force (hydraulic braking force or motor braking force).

The integrated controller 10 manages the energy consumption of the entire vehicle and has a function for running the vehicle with the highest efficiency. The integrated controller 10 detects the motor rotation speed Nm, and the second clutch output rotation speed. Information from the second clutch output rotational speed sensor 22 that detects N2out and the second clutch torque sensor 23 that detects the second clutch torque TCL2 and information obtained via the CAN communication line 11 are input.
Then, the integrated controller 10 controls the operation of the engine E according to the control command to the engine controller 1, the control of the motor generator MG according to the control command to the motor controller 2, and the control command to the first clutch controller 5. The engaging / disengaging control of the first clutch CL1 and the engaging / disengaging control of the second clutch CL2 by the control command to the AT controller 7 are performed.

[Motor generator cooling structure]
FIG. 2 is a longitudinal side view showing the cooling structure of the hybrid vehicle motor generator according to the first embodiment, and FIG. 3 is a longitudinal front view showing the cooling structure of the hybrid vehicle motor generator according to the first embodiment. Hereinafter, the cooling structure of the motor generator MG in the first embodiment will be described.

In the cooling structure of the first embodiment, an engine E, a motor generator MG, and an automatic transmission AT are connected in series to form a hybrid drive system, and the motor generator MG is built in the transmission case 34 of the automatic transmission AT. Then, the present invention is applied to a motor generator MG for a hybrid vehicle in which a cooling medium path 35 is set at the outer peripheral position of the motor generator MG (see FIG. 1).
The transmission case 34 incorporating the motor generator MG is a portion integrally extending in the axial direction from the end of the case main body incorporating the transmission power train on the transmission input shaft side toward the motor generator MG. is there.

As shown in FIG. 2, the inner surface 34a of the transmission case 34 has a cylindrical shape at a portion where the cooling medium path 35 is set.
A stepped surface 34b (fixed surface of the motor generator case 36) intersecting the cylindrical surface having a diameter smaller than the inner diameter of the inner surface 34a is formed on the automatic transmission AT side of the inner surface 34a of the transmission case 34. Yes. A large-diameter cylindrical inner surface 34c (assembly opening) having a diameter larger than the inner diameter of the inner surface 34a is formed on the engine E side of the inner surface 34a of the transmission case 34 (see FIG. 4).

In addition to the transmission case 34, a motor generator case 36 having an outer surface 36a having an outer diameter slightly smaller than the inner diameter (the diameter of the inner surface 34a) of the transmission case 34 is added to the motor generator MG. ing.
A fixed surface 36b that conforms to the step surface 34b is formed on the automatic transmission AT side of the outer surface 36a of the motor generator MG. A large-diameter cylindrical outer surface 36c corresponding to the cylindrical surface 34c is formed on the engine E side of the outer surface 36a of the motor generator MG (see FIG. 4).

  As shown in FIG. 2, the cooling medium path 35 is formed with an annular cooling groove 36d only in the outer surface 36a of the motor generator case 36, and the transmission case 34 and the motor generator case 36 are formed in a double cylindrical shape. It is set by sealing both ends sandwiched by the cooling groove 36d by the first annular seal 37 and the second annular seal 38.

As shown in FIG. 3 (a), the cooling medium path 35 is provided with a detent key 39 (partition plate) at one of the outer peripheral positions of the stator 32 of the motor generator MG. A cooling medium inlet port 40 is provided at the first end, and a cooling medium outlet port 41 is provided at the second end.
That is, the cooling medium passage 35 of the first embodiment supplies a cooling medium (for example, water) from the cooling medium inlet port 40 as shown in the schematic perspective view of FIG. This is a path through which the cooling medium flows and discharges the cooling medium from the cooling medium outlet port 41, and is formed over substantially the entire circumference except for the portion of the detent key 39.
The anti-rotation key 39 is a key for preventing the motor generator case 36 from rotating when the motor generator case 36 is engaged with the transmission case 34.

  As shown in FIG. 2, when the motor generator case 36 is fitted into a double cylindrical shape with respect to the inner surface 34a of the transmission case 34, the cooling medium path 35 is provided in the motor generator case 36. The first motor shaft 30, the rotor 31, the stator 32, and the resolver 42 constituting the single MG are assembled in advance.

  The resolver 42 is a sensor that detects the rotational angle position of the rotor 31, and is essential for controlling the motor generator MG. The resolver 42 includes a sensor rotor 42a provided on the first motor shaft 30, and the sensor rotor 42a. The stator teeth 42b provided in the resolver case 43 through a minute interval and coils 42c wound around the stator teeth 42b, and the rotational angle position of the rotor 31 is converted by converting the signals from the coils 42c. To detect. Here, the minute radial distance between the sensor rotor 42a and the stator teeth 42b is adjusted in advance in a sub-assembly process.

As shown in FIG. 2, the resolver case 43 is fixed to the motor generator case 36 by a case integrated bolt 45 together with a piston case 44 in which a piston oil passage of the first clutch CL1 is formed.
The first motor shaft 30 is spline-fitted with the second motor shaft 46 when assembled, and is connected to the transmission input shaft 47 via the damper 33. The transmission input shaft 47 is provided with an oil pump 48.
The motor generator case 36 is fixed to the transmission case 34 by case fixing bolts 49.
The first motor shaft 30 and the second motor shaft 46 are fixed to each other by a shaft integrated bolt 51 while fastening the driven plate bracket 50 of the first clutch CL1 together.

In FIG. 2, 52 is a first bearing interposed between the first motor shaft 30 and the motor generator case 36, and 53 is a first bearing interposed between the first motor shaft 30 and the resolver case 43. 2 bearings.
In FIG. 3, 54, 55, and 56 are U-phase, V-phase, and W-phase power cables that connect the inverter 3 and the coil 32 b of the stator 32.

[Motor generator assembly method]
FIG. 4 is an exploded cross-sectional view illustrating a method of assembling the motor generator MG of the first embodiment. Hereinafter, a method for assembling the motor generator MG of the first embodiment will be described.

  In the assembly method of the first embodiment, an engine E, a motor generator MG, and an automatic transmission AT are connected in series to form a hybrid drive system, and the motor generator MG is built in the transmission case 34 of the automatic transmission AT. In addition, the present invention is applied to a motor generator MG for a hybrid vehicle in which a cooling medium path 35 is set at the outer peripheral position of the motor generator MG.

  The method for assembling motor generator MG of the first embodiment includes a cooling groove forming step, a sub-assembly step, an assembling step, and a bolt fixing step.

  The cooling groove forming step is a step of forming an annular cooling groove 36d on at least one of the cylindrical inner surface 34a of the transmission case 34 and the cylindrical outer surface 36a of the motor generator case 36. Then, an annular cooling groove 36d is formed only on the cylindrical outer surface 36a of the motor generator case 36 by molding.

As shown in FIG. 4, the sub-assembly process is a process in which the first motor shaft 30, the rotor 31, the stator 32, and the resolver 42 constituting a single motor generator MG are assembled in advance to the motor generator case 36.
In this sub-assembly process, a laminated steel plate 32a in which thin steel plates, which are constituent elements of the stator 32, are laminated in the axial direction is shrink-fitted and fixed to the motor generator case 36. Further, in the subassembly process, as described above, the minute radial distance between the sensor rotor 42a and the stator teeth 42b of the resolver 42 is adjusted to be an appropriate distance on the entire circumference.
In this sub-assembly process, as shown in FIG. 4, the resolver case 43 and the piston case 44 are fixed to the motor generator case 36 by case integrated bolts 45, so that the first motor shaft 30 and the rotor 31 together with the resolver 42. And the stator 32 are assembled.

In the assembling step, the cylindrical inner surface 34a and the cylindrical outer surface 36a are used as fitting surfaces, the motor generator case 36 is fitted into the transmission case 34 in a double cylindrical shape, and is cooled simultaneously with the fitting. In this step, the cooling medium passage 35 is set by sealing both ends of the groove 36d with the first annular seal 37 and the second annular seal 38.
In the first embodiment, in this assembly process, as shown in FIG. 4, a motor generator case 36 in which members constituting the single unit of the motor generator MG are sub-assembled with respect to the transmission case 34 has a double cylindrical shape. Mated.

In the bolt fixing step, when the motor generator case 36 sub-assembled to the transmission case 34 is assembled, the sub-assembled motor generator case 36 is fixed to the transmission case 34 by case fixing bolts 49.
The first motor shaft 30 and the second motor shaft 46 are fixed to each other by the shaft integrated bolt 51 together with the first clutch CL1.

Next, the operation will be described.
[Operation of motor generator MG in cooling structure]
For example, as shown in FIG. 5, the cooling structure of the motor generator for a hybrid vehicle in which the motor is incorporated in the transmission is a water cooling type in which a part of the transmission case has a hollow structure and water is passed therethrough. Therefore, there are problems listed below.
-In manufacturing, since the minimum R of the casting core in the hollow portion of the case cannot be molded unless it is R6 (radius 6 mm) or more, the thickness (radial direction) of the hollow portion becomes thicker than necessary, and the case outer diameter increases. .
-Since the case thickness of the hollow part is required to some extent for strength, the case outer diameter is increased.
-Since the contact area of the water jacket cannot be made large in production (the structure and size of the core are limited), a certain amount of water flow is required to ensure cooling efficiency.
-Since the hollow part of the case is formed by casting using a core or insert, productivity and yield are poor.

  In contrast, in the hybrid vehicle motor generator cooling structure of the first embodiment, an annular cooling groove 36a is formed on at least one of the inner surface 34a of the transmission case 34 and the outer surface 36a of the motor generator case 36, The transmission case 34 and the motor generator case 36 are fitted in a double cylindrical shape, and both ends sandwiching the cooling groove 36a are sealed by the first annular seal 37 and the second annular seal 38 to thereby form the cooling medium path 35. By setting it, the productivity and yield of the case can be improved, and the motor generator MG can be cooled with high efficiency while improving the degree of freedom of layout and increasing the size of the motor generator.

That is, in the first embodiment, a clearance space between the transmission case 34 and the motor generator case 36 by the cooling groove 36a sealed at both ends is set as the cooling medium path 35 at the outer peripheral position of the motor generator MG.
Therefore, when setting the cooling medium path 35, for example, at the time of molding the motor generator case 36, only the cooling groove 36a is formed by simultaneous molding, and the case mold does not require a core or nest. Productivity and yield.
Further, in setting the cooling medium path 35, it is not necessary to increase the thickness in the radial direction more than necessary as in the case of casting using a core, and the outer diameter of the transmission case 34 can be made smaller than before, Layout flexibility is improved.
Further, when the outer diameter of the transmission case is set to the same diameter as the conventional case, in the case of the first embodiment, the case thickness in which the cooling medium path 35 is set can be reduced, so that the motor generator size can be increased accordingly. is there.
Furthermore, it is possible to arrange the cooling medium path 35 on the entire outer periphery of the motor generator MG, and the case thickness in the radial direction via the cooling groove 36a is compared with the case of casting using a core. Since the thickness can be reduced, the cooling medium with a wide contact area effectively removes heat from the motor generator MG, and the motor generator MG can be cooled with high efficiency.

  As a result, the productivity and yield of the case can be improved, and the motor generator MG can be cooled with high efficiency while improving the degree of freedom in layout and increasing the size of the motor generator.

In the cooling structure for the hybrid vehicle motor generator of the first embodiment, the cooling medium path 35 is set by forming an annular cooling groove 36 a only on the outer surface 36 a of the motor generator case 36.
For example, when a cooling medium path is formed between the transmission case and the motor generator case, if a cooling groove is provided on the transmission case side, it will not be removed by the mold, and post-processing is required.
On the other hand, by forming the annular cooling groove 36a only on the outer surface 36a of the motor generator case 36, the motor generator case mold allows the cooling groove portion to be pulled out, so that no post-processing is required, and the manufacturing cost is reduced.

In the hybrid vehicle motor generator cooling structure according to the first embodiment, the cooling medium path 35 is provided with a partition plate at one of the outer peripheral positions of the stator 32 of the motor generator MG, and the first partition plate is sandwiched between the first and second partition plates. A cooling medium inlet port 40 is provided at the end, and a cooling medium outlet port 41 is provided at the second end.
Therefore, by dividing the cooling medium path 35 by one partition plate, the flow of the cooling medium can be given direction, and the cooling medium inlet port 40 and the cooling medium outlet port 41 can be arranged together. This improves the flexibility of layout.

In the cooling structure for a hybrid vehicle motor generator according to the first embodiment, the partition plate is provided with a detent key 39 for preventing the motor generator case 36 from rotating in a fitted state of the motor generator case 36 with respect to the transmission case 34. did.
Therefore, as a partition plate for the cooling medium passage 35, the motor generator case 36 can be achieved with both the anti-rotation function and the partition function by effectively using the anti-rotation key 39 without adding any new components. .

In the cooling structure of the motor generator for a hybrid vehicle according to the first embodiment, the cooling medium passage 35 is formed when the motor generator case 36 is fitted into the inner surface 34a of the transmission case 34 in a double cylindrical shape. In the case 36, the first motor shaft 30, the rotor 31, the stator 32, and the resolver 42 constituting the motor generator MG alone are assembled in advance.
For example, when the stator of a motor generator is fixed inside the transmission case, subassembly as a motor generator alone cannot be performed, productivity (assembly) is poor, and stable motor performance cannot be guaranteed. Furthermore, the adjustment of the resolver essential for the motor generator is also the adjustment after assembly, and the assembly workability is poor.
On the other hand, in the first embodiment, since the motor generator MG includes a single motor generator MG (= sub-assembly) in which the first motor shaft 30, the rotor 31, the stator 32, and the resolver 42 are previously assembled in the motor generator case 36, productivity is increased. As a result, the stable motor performance can be guaranteed, and in addition, the resolver 42 can be adjusted before assembly, and the assembly workability is also improved.

[Operation in motor generator MG assembly method]
In the method of assembling the motor generator MG according to the first embodiment, the cooling in which the annular cooling groove 36d is formed on at least one of the cylindrical inner surface 34a of the transmission case 34 and the cylindrical outer surface 36a of the motor generator case 36. A groove forming step, the cylindrical inner surface 34a and the cylindrical outer surface 36a are used as fitting surfaces, the motor generator case 36 is fitted into the transmission case 34 in a double cylindrical shape, and cooled simultaneously with the fitting. An assembly step for setting the cooling medium path 35 by sealing both ends of the groove 36d with the first annular seal 37 and the second annular seal 38.

Conventionally, since the motor generator is directly assembled to the transmission case, the water jacket corresponding to the cooling medium passage 35 of the present application is set to the transmission case that also serves as the motor generator case. When this water jacket is set as a transmission case, a core and a nest are required for the case mold, and casting is performed after many processes, so that the productivity of the transmission case is deteriorated.
Further, the water jacket formed by using the core or the insert is partially arranged on the outer periphery of the motor generator due to the limitation by casting. In addition, the radial case thickness between the water jacket and the motor generator needs to be secured to some extent due to the limitation by casting. Therefore, the contact area of the cooling medium is reduced and the heat removal distance from the motor generator is increased, so that the motor generator MG cannot be cooled with high efficiency. Moreover, in order to ensure cooling performance, the flow rate of the cooling medium has to be increased.

On the other hand, in the first embodiment, the cooling medium is formed by the cooling groove forming step for forming the cooling groove 36d on the surface that can be easily molded and processed, and the assembly step for fitting and assembling the motor generator case 36 to the transmission case 34. Since the path 35 is set, productivity can be improved by a simple process that does not require a core or a nest in the mold of the transmission case 34 and does not require labor.
Furthermore, the cooling medium path 35 set by the cooling groove forming step and the assembling step can be arranged on the entire outer periphery of the motor generator MG, and the radial case thickness via the cooling groove 36a is Since it can be made thinner than in the case of casting using a core, the cooling medium with a large contact area can effectively remove heat from the motor generator MG, and the motor generator MG can be cooled with high efficiency. .

In the method for assembling the motor generator MG of the first embodiment, in the cooling groove forming step, the annular cooling groove 36d is formed only on the cylindrical outer surface 36a of the motor generator case 36 by molding.
For example, when a cooling medium path is formed between the transmission case and the motor generator case, if a cooling groove is provided on the transmission case side, it will not be removed by the mold, and post-processing is required.
On the other hand, in the cooling groove forming step, the annular cooling groove 36a is formed only on the outer surface 36a of the motor generator case 36, so that the motor generator case mold is formed so that the cooling groove portion can be removed, so that no post-processing is required. Cost can be reduced.

In the method of assembling the motor generator MG according to the first embodiment, a sub-assembly process for pre-assembling the first motor shaft 30, the rotor 31, the stator 32, and the resolver 42 constituting the motor generator MG alone is added to the motor generator case 36. In the assembling step, the sub-assembled motor generator case 36 is fitted into the transmission case 34 in a double cylindrical shape.
For example, when the stator of a motor generator is fixed inside the transmission case, subassembly as a motor generator alone cannot be performed, productivity (assembly) is poor, and stable motor performance cannot be guaranteed. Furthermore, the adjustment of the resolver essential for the motor generator is also the adjustment after assembly, and the assembly workability is poor.
On the other hand, in the first embodiment, a sub-assembly process in which the first motor shaft 30, the rotor 31, the stator 32, and the resolver 42 are assembled in advance is added to the motor generator case 36. Therefore, productivity is improved and stable motor performance is achieved. In addition, the resolver 42 can be adjusted in the sub-assembly process, and the assembly workability is improved.
In particular, when the resolver adjustment is performed in the sub-assembly process, the resolver adjustment is not necessary in the main process of assembling the automatic transmission AT, so that the main process can be smoothly performed.

In the method of assembling the motor generator MG of the first embodiment, in the sub-assembly process, a laminated steel plate 32a in which thin steel plates, which are constituent elements of the stator 32, are laminated in the axial direction is shrink-fitted and fixed to the motor generator case 36.
For example, when water-cooling a motor generator, in order to increase the cooling effect, the motor generator (laminated steel plate of the stator) and the case must be in close contact with each other, and the laminated steel plate of the stator needs to be shrink-fitted into the case. is there. Conventionally, the stator steel plate is directly shrink-fitted and fixed inside the transmission case, so it is necessary to perform processing of parts that require dimensional accuracy after shrink-fitting (since thermal distortion occurs). Deteriorate.
On the other hand, in the first embodiment, in the sub-assembly process, the laminated steel plate 32a of the stator 32 is shrink-fitted and fixed to the motor generator case 36, so that the sub-assembly process is performed up to the processing of the part that requires dimensional accuracy. In this way, post-shrink processing after assembling the motor generator case 36 to the transmission case 34 can be minimized, and productivity is greatly improved.

Next, the effect will be described.
In the cooling structure for the hybrid vehicle motor generator of the first embodiment, the effects listed below can be obtained.

  (1) An engine E, a motor generator MG, and an automatic transmission AT are connected in series to form a hybrid drive system. The motor generator MG is built in the transmission case 34 of the automatic transmission AT, and the motor generator In the cooling structure of the hybrid vehicle motor generator in which the cooling medium path 35 is set at the outer peripheral position of the MG, the inner surface 34a of the transmission case 34 has a cylindrical shape, and the motor generator MG is separated from the transmission case 34, An outer surface 36a having an outer diameter slightly smaller than the inner diameter of the transmission case 34 is added to a cylindrical motor generator case 36, and the cooling medium path 35 includes an inner surface 34a of the transmission case 34 and the motor generator case 46. An annular cooling groove 36d is formed on at least one of the outer surfaces 36a of the transmission case 3 4 and the motor generator case 36 are fitted in a double cylindrical shape, and both ends sandwiching the cooling groove 36d are sealed by the first annular seal 37 and the second annular seal 38. In addition to improving productivity and yield, the motor generator MG can be cooled with high efficiency while improving the degree of freedom in layout and increasing the size of the motor generator.

  (2) Since the cooling medium path 35 is set by forming the annular cooling groove 36a only on the outer surface 36a of the motor generator case 36, the cooling medium path 35 is shaped so as to come out to the cooling groove portion in the motor generator case type, and no post-processing is required. , Manufacturing costs can be reduced.

  (3) The cooling medium path 35 is provided with a partition plate at one position of the entire outer peripheral position of the stator 32 of the motor generator MG, and the cooling medium inlet port 40 is provided at the first end with the partition plate interposed therebetween. Since the cooling medium outlet port 41 is provided at the two ends, the cooling medium inlet port 40 and the cooling medium outlet port 41 can be arranged together while giving direction to the flow of the cooling medium. Increased freedom can be achieved.

  (4) Since the partition plate is a non-rotating key 39 that prevents the motor generator case 36 from rotating in the fitted state of the motor generator case 36 with respect to the transmission case 34, the partition plate of the cooling medium path 35 is By making effective use of the non-rotating key 39 without adding new parts, the motor generator case 36 can be achieved with both a non-rotating function and a partition function.

  (5) When the motor generator case 36 is fitted to the inner surface 34a of the transmission case 34 in a double cylindrical shape, the cooling medium path 35 constitutes the motor generator MG alone. Since the first motor shaft 30, the rotor 31, the stator 32, and the resolver 42 are assembled in advance, productivity can be improved and stable motor performance can be guaranteed. In addition, the resolver 42 can be adjusted before assembly. As a result, the assembly workability can be improved.

  In the method for assembling the motor generator for a hybrid vehicle according to the first embodiment, the effects listed below can be obtained.

  (6) The engine E, the motor generator MG, and the automatic transmission AT are connected in series to form a hybrid drive system, and the motor generator MG is built in the transmission case 34 of the automatic transmission AT, and the motor generator In the hybrid vehicle motor generator in which the cooling medium path 35 is set at the outer peripheral position of the MG, at least one of the cylindrical inner surface 34a of the transmission case 34 and the cylindrical outer surface 36a of the motor generator case 36 is annular. A cooling groove forming step for forming a cooling groove 36d, the cylindrical inner surface 34a and the cylindrical outer surface 36a as fitting surfaces, and the motor generator case 36 is fitted into the transmission case 34 in a double cylindrical shape; At the same time as fitting, both ends sandwiching the cooling groove 36d are sealed by the first annular seal 37 and the second annular seal 38. And an assembly process for setting the reject medium path 35, so that the productivity of the transmission case 34 can be improved by a simple process that does not require a core or a nest in the mold of the transmission case 34. In addition, the cooling medium path 35 for cooling the motor generator MG with high efficiency can be set.

  (7) In the cooling groove forming step, since the annular cooling groove 36d is formed only by molding on the cylindrical outer surface 36a of the motor generator case 36, the motor generator case mold has a shape that extends to the cooling groove portion and requires post-processing. This eliminates the manufacturing cost.

  (8) A sub-assembly process in which the first motor shaft 30, the rotor 31, the stator 32, and the resolver 42 constituting a single motor generator MG are added to the motor generator case 36 in advance, and the assembly process includes the transmission Since the sub-assembled motor generator case 36 is fitted to the case 34 in a double cylindrical shape, productivity is improved and stable motor performance can be guaranteed, and in addition, adjustment of the resolver 42 is performed in the sub-assembly process. The assembly workability can be improved.

  (9) In the sub-assembly process, a laminated steel plate 32a in which thin steel plates constituting the stator 32 are laminated in the axial direction is shrink-fitted and fixed to the motor generator case 36. By completing the sub-assembly process as much as possible, post-shrinking after assembly of the motor generator case 36 to the transmission case 34 can be minimized, and productivity can be greatly improved.

  The second embodiment is an example in which the first annular seal and the second annular seal in the cooling structure for the hybrid vehicle motor generator of the first embodiment are multiple seals having higher sealing performance.

First, the configuration will be described.
FIG. 6 is an enlarged cross-sectional view showing a cooling structure (cooling medium path portion) of the hybrid vehicle motor generator according to the second embodiment.
In the cooling medium path 35 of the second embodiment, the first annular seal 37 and the second annular seal 38 are respectively formed as a first O-ring 37a, 37b, 37c and a second O-ring 38a, 38b, 38c having a triple structure. .

  The first O-rings 37a, 37b, and 37c and the second O-rings 38a, 38b, and 38c having the triple structure are set on the motor generator case 36 side and between the adjacent first O-rings 37a, 37b, and 37c. The first grooves 37d and 37e are formed in the motor generator case 36, and the second grooves 38d and 38e are formed in the motor generator case 36 between the adjacent second O-rings 38a, 38b and 38c.

  The first grooves 37d and 37e formed in the motor generator case 36 communicate with the first drain holes 37f and 37g communicating with the outside air, and the second grooves 38d and 38e formed in the motor generator case 36 communicate with the outside air. The second drain holes 38f and 38g are formed in the transmission case 34. Since other configurations are the same as those of the first embodiment, illustration and description thereof are omitted.

Next, the operation will be described.
In the hybrid vehicle motor generator cooling structure according to the second embodiment, the cooling medium path 35 includes a first O-ring 37a, 37b, 37c having a first annular seal 37 and a second annular seal 38, each having a triple structure. The second O-rings 38a, 38b, and 38c were used.
Therefore, higher sealing performance can be obtained than when only a single O-ring is used as an annular seal, and leakage of the cooling medium from the cooling medium path 35 and oil mixture from the oil chamber or the piston oil path are surely prevented. be able to.

In the cooling structure for a hybrid vehicle motor generator according to the second embodiment, the first O-rings 37a, 37b, 37c and the second O-rings 38a, 38b, 38c having the triple structure are set on the motor generator case 36 side. First grooves 37d, 37e are formed in the motor generator case 36 between the adjacent first O-rings 37a, 37b, 37c, and the motor generator case 36 between the adjacent second O-rings 38a, 38b, 38c is formed. Second grooves 38d and 38e were formed.
Therefore, even if a cooling medium (for example, water) or oil leaks from one of the adjacent O-rings, it immediately flows into the first groove 37d, 37e or the second groove 38d, 38e, so that the oil chamber or cooling is immediately performed. Mixing in the medium path 35 can be prevented.

In the hybrid vehicle motor generator cooling structure according to the second embodiment, the first grooves 37d and 37e formed in the motor generator case 36 and the first drain holes 37f and 37g communicating with the outside air, and the motor generator case 36 are provided. The formed second grooves 38d, 38e and second drain holes 38f, 38g communicating with the outside air are formed in the transmission case 34.
Therefore, even if the coolant or oil accumulates in the first grooves 37d and 37e and the second grooves 38d and 38e, the coolant is drained to the outside of the transmission case 34, so that the coolant is mixed into the oil chamber or the coolant path 35 It is possible to reliably prevent oil from being mixed into the oil.
Since other operations are the same as those in the first embodiment, description thereof is omitted.

Next, the effect will be described.
In the hybrid vehicle motor generator cooling structure of the second embodiment, the following effects can be obtained in addition to the effects (1) to (5) of the first embodiment.

  (10) In the cooling medium path 35, the first annular seal 37 and the second annular seal 38 are respectively formed as a first O-ring 37a, 37b, 37c and a second O-ring 38a, 38b, 38c having a triple structure. Further, it is possible to reliably prevent cooling medium leakage from the cooling medium passage 35 and oil mixture from the oil chamber or the piston oil passage.

  (11) The first O-rings 37a, 37b, and 37c and the second O-rings 38a, 38b, and 38c having the triple structure are set on the motor generator case 36 side and adjacent to the first O-rings 37a, 37b, and 37c. Since the first grooves 37d and 37e are formed in the motor generator case 36 between and the second O-rings 38a, 38b and 38c between the adjacent second O-rings 38a, 38b and 38c, the second grooves 38d and 38e are formed adjacent to each other. Even if the cooling medium or oil leaks from one of the O-rings, it once flows into the first grooves 37d, 37e and the second grooves 38d, 38e, and immediately enters the oil chamber or the cooling medium path 35. Can be prevented.

  (12) The first grooves 37d and 37e formed in the motor generator case 36, the first drain holes 37f and 37g communicating with the outside air, the second grooves 38d and 38e formed in the motor generator case 36, and the outside air Since the second drain holes 38f and 38g communicating with the transmission case 34 are formed in the transmission case 34, it is possible to reliably prevent the coolant from entering the oil chamber and the oil from entering the coolant passage 35. it can.

  As described above, the cooling structure and the assembling method of the motor generator for a hybrid vehicle according to the present invention have been described based on the first embodiment and the second embodiment. However, the specific configuration is not limited to these embodiments. Design changes and additions are permitted without departing from the spirit of the invention according to each of the claims.

  In the first and second embodiments, the example in which the annular cooling groove is formed only on the outer surface of the motor generator case is shown. However, as shown in FIG. 7, for example, the annular cooling groove is formed only on the inner surface of the transmission case. Although not shown, annular cooling grooves may be formed on both the inner surface of the transmission case and the outer surface of the motor generator case. In short, any configuration in which an annular cooling groove is formed on at least one of the inner surface of the transmission case and the outer surface of the motor generator case is included in the present invention.

  In the first and second embodiments, the example of setting the cooling medium path by fitting the motor generator case sub-assembled to the transmission case in a double cylindrical shape has been shown. On the other hand, the present invention includes a case in which the motor generator case is fitted into a double cylinder to set the cooling medium path.

  In the first and second embodiments, examples of application to a rear-wheel drive hybrid vehicle motor generator have been shown. However, a front-wheel drive hybrid vehicle motor generator, a four-wheel drive hybrid vehicle motor generator, and further to a drive system The present invention can also be applied to a hybrid vehicle motor generator that does not have the first clutch. In short, the engine, motor generator, and transmission are connected in series to form a hybrid drive system, the motor generator is built in the transmission case of the transmission, and the cooling medium path is set at the outer peripheral position of the motor generator. Any motor generator for hybrid vehicles can be applied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall system diagram showing a rear-wheel drive hybrid vehicle to which a hybrid vehicle motor generator cooling structure according to a first embodiment is applied. It is a vertical side view which shows the cooling structure of the motor generator for hybrid vehicles of Example 1. FIG. It is a longitudinal front view which shows the cooling structure of the motor generator for hybrid vehicles of Example 1. FIG. FIG. 3 is an exploded cross-sectional view illustrating a method for assembling the motor generator MG of the first embodiment. It is an expanded sectional view which shows the cooling structure of the conventional motor generator for hybrid vehicles. FIG. 6 is an enlarged cross-sectional view illustrating a cooling structure of a motor generator for a hybrid vehicle according to a second embodiment. It is a vertical side view which shows the other example of the cooling structure of the motor generator for hybrid vehicles.

Explanation of symbols

E engine
FW flywheel
CL1 1st clutch
MG motor generator
CL2 2nd clutch
AT automatic transmission (transmission)
PS propeller shaft
DF differential
DSL left drive shaft
DSR right drive shaft
RL left rear wheel
RR right rear wheel
FL Left front wheel
FR Right front wheel 1 Engine controller 2 Motor controller 3 Inverter 4 Battery 5 First clutch controller 6 First clutch hydraulic unit 7 AT controller 8 Second clutch hydraulic unit 9 Brake controller 10 Integrated controller 30 First motor shaft (motor shaft)
31 Rotor 32 Stator 32a Laminated steel rod 33 Damper 34 Transmission case 34a Inner surface 35 Cooling medium path 36 Motor generator case 36a Outer surface 36d Cooling groove 37 First annular seal 38 Second annular seal 39 Non-rotating key (partition plate)
40 Cooling medium inlet port 41 Cooling medium outlet port 42 Resolver

Claims (6)

A hybrid in which an engine, a motor generator, and a transmission are connected in series to form a hybrid drive system, the motor generator is built in a transmission case of the transmission, and a cooling medium path is set at an outer peripheral position of the motor generator In the cooling structure of a car motor generator,
The inner surface of the transmission case has a cylindrical shape,
In addition to the transmission case, a motor generator case having a cylindrical outer surface with an outer diameter slightly smaller than the inner diameter of the transmission case is added to the motor generator,
The cooling medium path is formed with an annular cooling groove on at least one of an inner surface of the transmission case and an outer surface of the motor generator case, and the transmission case and the motor generator case are formed in a double cylindrical shape. And set by sealing both ends of the cooling groove with the first annular seal and the second annular seal ,
A partition plate is provided in the cooling medium path at one of all the outer peripheral positions of the stator of the motor generator, a cooling medium inlet port is provided at the first end, and a cooling medium outlet is provided at the second end across the partition plate. A port,
The cooling structure for a hybrid vehicle motor generator, wherein the partition plate is a non-rotating key that prevents the motor generator case from rotating when the motor generator case is fitted to the transmission case . In the cooling structure of the motor generator for hybrid vehicles described in Claim 1,
The cooling structure of the hybrid vehicle motor generator is characterized in that the cooling medium path is set by forming an annular cooling groove only on the outer surface of the motor generator case. In the cooling structure of the motor generator for hybrid vehicles according to claim 1 or 2,
When the motor generator case is fitted in a double cylindrical shape to the inner surface of the transmission case, the cooling medium path is provided with a motor shaft, a rotor, a stator, and a resolver that constitute a motor generator alone. A cooling structure of a motor generator for a hybrid vehicle, characterized by being assembled in advance . In the cooling structure of the motor generator for hybrid vehicles described in any one of Claims 1 thru | or 3 ,
The cooling structure of the hybrid vehicle motor generator is characterized in that the cooling medium path is an O-ring having a multiple configuration in which each of the first annular seal and the second annular seal is double or more . In the cooling structure of the motor generator for hybrid vehicles described in Claim 4 ,
The cooling structure for a hybrid vehicle motor generator , wherein the O-ring having the multiple configuration is set on the motor generator case side, and a groove is formed in a motor generator case between adjacent O-rings . In the cooling structure of the motor generator for hybrid vehicles described in Claim 5 ,
A cooling structure for a motor generator for a hybrid vehicle , wherein a drain hole for communicating a groove formed in the motor generator case with outside air is formed in the transmission case .

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