DRIVING DEVICE

A driving device includes an electric motor configured to drive a wheel of a vehicle, a gear connected to the electric motor, a casing accommodating at least one of the electric motor and the gear, a high voltage component fixed to a side wall of the casing from outside of the casing and electrically connected to the electric motor, and a cover fixed to the side wall of the casing from outside of the casing and covering the high voltage component. The cover is connected to a constituent member located outside the cover.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2022-201388 filed on Dec. 16, 2022 incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The technology of the present disclosure relates to a driving device.

2. Description of Related Art

U.S. Pat. No. 9,692,277 discloses a driving device that includes an electric motor that drives a wheel of a vehicle, a casing that accommodates the electric motor, an inverter body, and a cover that covers the inverter body. The driving device is fixed to a subframe of the vehicle via a bracket.

SUMMARY

In a vehicle, vibration is sometimes applied to a cover that covers an inverter body. In the driving device described above, since the inverter body is fixed to the cover, vibration applied to the cover is directly transmitted to the inverter body. The present disclosure provides a technology capable of reducing vibration transmitted to a high voltage component covered by a cover.

A first aspect of the disclosure relates to a driving device including an electric motor, a gear, a casing, a high voltage component, and a cover. The electric motor is configured to drive wheels of a vehicle. The gear is connected to the electric motor. The casing accommodates at least one of the electric motor and the gear. The high voltage component is fixed to a side wall of the casing from the outside of the casing and is electrically connected to the electric motor. The cover is fixed to the side wall of the casing from the outside of the casing and covers the high voltage component. In the driving device, the cover is connected to a constituent member located outside the cover.

In the first aspect, the casing may accommodate the electric motor and the gear.

In the first aspect, the casing may have a first casing that accommodates the electric motor and a second casing that accommodates the gear.

In the first aspect, the high voltage component, the electric motor, and the gear may be arranged in order of the high voltage component, the electric motor, and the gear along an axial direction parallel to a rotation axis of the electric motor.

In the first aspect, the high-voltage component, the electric motor, and the gear may be arranged in order of the high voltage component, the gear, and the electric motor along an axial direction parallel to a rotation axis of the electric motor.

In the first aspect, the constituent member may include at least one of a vehicle body of the vehicle, a member fixed to the vehicle body, and a vibration generating member, and the cover may be connected to the constituent member through a bracket.

In the first aspect, the vehicle may include a subframe fixed to the vehicle body, and the constituent member may include a supporting mount provided in the subframe.

In the first aspect, the vehicle may include a compressor for air conditioning, and the vibration generating member may include the compressor.

In the first aspect, the vehicle may be a hybrid vehicle including an engine fixed to a vehicle body, and the electric motor and the engine may be arranged along an axial direction parallel to a rotation axis of the electric motor.

In the first aspect, the side wall of the casing may extend in a direction intersecting with a rotation axis of the electric motor of the casing, and the constituent member may face an outer surface of the side wall.

In the first aspect, the side wall of the casing may extend along a rotation axis of the electric motor of the casing and the constituent member may face an outer surface of the side wall.

In the first aspect, the high voltage component may be an inverter or/and a DC/DC converter.

In the first aspect, the high voltage component may be a component with an operating voltage range of above DC 60 V to DC 1500 V, or above AC 30 V to AC 1000 V in root mean square value.

In the vehicle described above, vibration of the constituent member located outside the cover is transmitted to the cover that covers the high voltage component. The high voltage component is fixed to the side wall of the casing from the outside of the casing. Therefore, the vibration transmitted from the constituent member to the cover is transmitted to the high voltage component through the side wall of the casing. Thus, with each aspect of the present disclosure, vibration transmitted from the constituent member to the high voltage component can be reduced compared to the technology of the related art in which vibration transmitted from the constituent member to the cover is directly transmitted to the high voltage component.

Details and further improvements in the technology of the present disclosure are described in the “DETAILED DESCRIPTION OF EMBODIMENTS”.

DETAILED DESCRIPTION OF EMBODIMENTS

In an embodiment of the present technology, the casing may accommodate the electric motor and the gear. However, in another embodiment, the casing may not accommodate the gear, for example.

In an embodiment of the present technology, the casing may include a first casing that accommodates the electric motor and a second casing that accommodates the gear. However, in another embodiment, for example, the first casing may accommodate the electric motor and the gear.

In an embodiment of the present technology, the high voltage component, the electric motor, and the gear may be arranged in this order along an axial direction parallel to a rotation axis of the electric motor. However, in another embodiment, the high voltage component, the electric motor, and the gear may be arranged in this order along the axial direction parallel to the rotation axis of the electric motor, or they may be arranged along the axial direction parallel to the rotation axis of the electric motor in order of the electric motor, the high voltage component, and the gear.

In an embodiment of the present technology, the constituent member may include at least one of a vehicle body of the vehicle, a member fixed to the vehicle body, and a vibration generating member. In this case, the cover may be connected to the constituent member via a bracket. With such a configuration, for example, it is possible to suppress transmission of vibrations, whether caused by traveling of the vehicle or originating from the vibration generating member, to the high voltage component through the bracket.

In an embodiment of the present technology, the vehicle may include a subframe fixed to the vehicle body, and the constituent member may include a supporting mount provided on the subframe. With such a configuration, it is possible to suppress transmission of vibration of the supporting mount provided on the subframe to the high voltage component through a bracket.

In an embodiment of the present technology, the vehicle may include a compressor for air conditioning, and the vibration generating member may be the compressor. With such a configuration, it is possible to suppress transmission of vibration of the compressor to the high voltage component through a bracket.

In an embodiment of the present technology, the vehicle may be a hybrid vehicle including an engine fixed to a vehicle body. In this case, the electric motor and the engine may be arranged along an axial direction parallel to a rotation axis of the electric motor. However, in another embodiment, the engine and the motor may be arranged along a direction orthogonal to the rotation axis of the electric motor.

In an embodiment of the present technology, the side wall of the casing may extend in a direction that intersects a rotation axis of the electric motor of the casing. In this case, the constituent member may face an outer surface of the side wall. However, in another embodiment, the side wall of the casing may extend along a rotation axis of the electric motor of the casing. In this case, the constituent member may face an outer surface of the side wall.

First Example

FIG.1illustrates a plan view of an electric vehicle100equipped with a driving device10of a first example. The electric vehicle100includes a vehicle body2, a front drive shaft5F, a pair of front wheels4F, a rear drive shaft5R, a pair of rear wheels4R, a battery pack6, a rear suspension member8, and a compressor70in addition to the driving device10. For easy understanding,FIG.1illustrates the vehicle body2of the electric vehicle100with a dashed line. The electric vehicle100in the present disclosure includes electric vehicles as well as fuel cell vehicles. In the coordinate system in the drawing, FR indicates the front of the electric vehicle100, UP indicates the top of the electric vehicle100, and LH indicates the left side of the electric vehicle100. In the following, “up”, “down”, “left”, “right”, “front”, and “rear” are described based on the coordinate system in the drawings.

One front wheel4F is provided at one end of the front drive shaft5F, and the other front wheel4F is provided at the other end of the front drive shaft5F. Also, one rear wheel4R is provided at one end of the rear drive shaft5R, and the other rear wheel4R is provided at the other end of the rear drive shaft5R.

The driving device10is located below a rear seat (not illustrated) of the electric vehicle100and above the rear suspension member8. In a modification example, the driving device10may be located below a board forming a bottom surface of a luggage space of the electric vehicle100. The driving device10drives the rear wheels4R via the rear drive shaft5R of the electric vehicle100. The driving device10includes a casing11, an inverter unit20, a gear unit30, and a motor unit40. The inverter unit20has an inverter22. The gear unit30has a link gear32, a counter gear33, and a differential gear34. The motor unit40has a motor42.

The battery pack6is arranged below a floor panel9(seeFIG.2) of the electric vehicle100. The battery pack6supplies electric power to the driving device10. Thereby, the driving device10drives the rear wheels4R. The driving device10also functions as a generator. The battery pack6stores electric power supplied from the driving device10. The inverter22is connected to the battery pack6by a power cable7. The inverter22converts direct current power of the battery pack6into alternating current power suitable for driving the motor42. Thus, the inverter22is a high voltage component to which high voltage power is applied. Here, the term “high voltage” refers to an operating voltage range of above DC 60 V to DC 1500 V, or above AC 30 V (root mean square value) to AC 1000 V (root mean square value). A “high voltage component” in the present disclosure may typically be a component that is electrically connected to the motor42and has a function of controlling electric power supplied to the motor42. In this case, a cable connected to the motor42does not correspond to the “high voltage component”. In a modification example, the driving device10may incorporate a DC/DC converter that boosts the direct current power of the battery pack6instead of, or in addition to, the inverter22, for example.

The compressor70is located in a front component3of the electric vehicle100. The compressor70is an air-conditioning compressor that adjusts the temperature of a vehicle cabin of the electric vehicle100.

An internal structure of the driving device10will be described with reference toFIG.2. The casing11of the driving device10is a rectangular box and forms a space for accommodating the motor42and a space for accommodating the link gear32, the counter gear33, and the differential gear34of the gear unit30. The casing11has a left side wall14at a left end. The left side wall14is an outer wall that separates the inside and outside of the casing11and extends in the vertical direction. The driving device10is fixed to the rear suspension member8via a pair of brackets60L,60R and a pair of supporting mounts50L,50R. The rear suspension member8is fixed to an upper surface of the floor panel9of the vehicle body2of the electric vehicle100. The rear suspension member8is a subframe of the electric vehicle100formed by combining a plurality of frames. The supporting mounts50L,50R are members provided on the rear suspension member8. The supporting mount50L is a member that connects the rear suspension member8and the bracket60L. The supporting mount50R is a member that connects the rear suspension member8and the bracket60R. The brackets60L,60R have symmetrical shapes with respect to each other. Similarly, the supporting mounts50L,50R have symmetrical shapes with respect to each other. This description will primarily focus on the structures of the left bracket60L and the supporting mount50L among these components.

The motor42inside the casing11is a so-called electric motor, and includes a rotor44and a stator core46. The rotor44extends in the right and left direction along a rotation axis A1of the motor42. The rotor44is made of a magnetic material and accommodates a permanent magnet (not illustrated) inside. The rotor44has a motor shaft47extending in an axial direction (that is, right and left direction) parallel to the rotation axis A1. The motor shaft47is rotatably supported by the casing11via a pair of bearings49.

Also, as illustrated inFIG.2, in the driving device10, the inverter unit20, the gear unit30, and the motor unit40are arranged in this order from the left side along an axial direction parallel to the rotation axis A1. Further, the gear unit30is located between the motor42and the inverter22. In a modification example, a cooling unit which supplies, to the inverter unit20, a heat transfer medium for cooling the inverter22of the inverter unit20may be interposed between the inverter unit20and the gear unit30. That is, in a modification example, in addition to the units20,30, and40, other members may be arranged between the units20,30, and40.

By arranging the units20,30, and40in the right and left direction in this way; for example, the size of the driving device10in the vertical direction can be reduced compared to a configuration in which the units20,30, and40are arranged in the vertical direction, respectively. Thereby; the cabin space of the electric vehicle100can be enlarged. Also, the left side wall14extends in a direction intersecting with the rotation axis A1.

The stator core46has a cylindrical shape and extends in the right and left direction along the rotation axis A1. The stator core46is located radially outside the rotor44. A gap is provided between the stator core46and the rotor44. The stator core46is made of a magnetic material. A stator coil48is provided on the stator core46. The stator coil48is made of a conductive body and wound around an outer surface of the stator core46. The stator coil48of the motor unit40is electrically connected to the inverter22of the inverter unit20. When the electric power of the battery pack6is supplied to the stator coil48through the inverter22, a magnetic force is generated between the stator coil48and the rotor44. This causes the rotor44to rotate around the rotation axis A1.

The motor shaft47extends leftward from the motor unit40until it reaches the link gear32of the gear unit30. The motor shaft47is connected to the link gear32of the gear unit30. That is, the motor42is mechanically connected to the link gear32via the motor shaft47. Thereby, rotation of the rotor44of the motor42is transmitted to the link gear32. The link gear32meshes with the counter gear33. The counter gear33meshes with the differential gear34. That is, the link gear32is mechanically connected to the differential gear34via the counter gear33. The differential gear34is mechanically connected to the rear drive shaft5R. Thereby, the rotation of the link gear32is transmitted to the rear drive shaft5R via the counter gear33and the differential gear34. Thus, the motor42drives the rear wheels4R through the three gears32,33, and34of the gear unit30. In a modification example, the gear unit30may not include the counter gear33, for example. In this case, the link gear32and the differential gear34may mesh directly.

The inverter unit20includes a cover21in addition to the inverter22. The inverter22includes a plurality of switching elements. The inverter22is fixed to the left side wall14of the casing11with a plurality of bolts B2from the left side of the casing11. The inverter22is fixed to the left side wall14of the casing11from the outside of the casing11.

The cover21of the inverter unit20has a box shape with an open right side. The cover21includes an end wall24, an annular wall23, and a pair of flanges26U,26D. An outer peripheral edge of the end wall24extending in the vertical direction is connected to the flanges26U,26D by the annular wall23extending in the right and left direction. After the inverter22is fixed to the left side wall14of the casing11, the cover21is fixed to the left side wall14around the left side of the inverter22. As a result, the cover21covers the inverter22from the left side. The inverter22is fixed to the left side wall14of the casing11via the flanges26U,26D and the bolts B2from the left side of the casing11. The casing11may further accommodate a smoothing capacitor for smoothing the output of the inverter22and/or a filter for suppressing noise from occurring in the input of the inverter22.

The bracket60L is fixed to the end wall24of the cover21with a plurality of bolts B1. The bracket60L includes a fixing portion that abuts the end wall24of the cover21, and a body portion bent into an L shape. A boss of the supporting mount50L is inserted into a lower end portion of the body portion of the bracket60L. Thereby, the bracket60L is fixed to the supporting mount50L. As a result, as illustrated inFIG.2, a left side surface of the left side wall14faces the supporting mount50L. In a modification example, the bracket60L may be fixed to the end wall24of the cover21with an adhesive or by welding.

As an example, when the electric vehicle100travels, the vehicle body2(for example, floor panel9) vibrates. In this case, vibration of the floor panel9is transmitted to the driving device10via the rear suspension member8, the supporting mounts50L,50R, and the brackets60L,60R. Here, in particular, it is required to reduce the vibration of the inverter22, which is a high voltage component. The inverter22is covered with the cover21, and the cover21is fixed to the rear suspension member8via the supporting mount50L and the bracket60L. Therefore, the vibration of the supporting mount50L is transmitted through the bracket60L to the cover21covering the inverter22.

In the driving device10, the inverter22is fixed to the left side wall14of the casing11from the outside of the casing11. That is, the inverter22is not directly fixed to the cover21that covers the inverter22. Therefore, even when vibration is transmitted from the supporting mount50L to the cover21, the vibration is not directly transmitted from the cover21to the inverter22. The vibration is first transmitted to the left side wall14of the casing11and transmitted to the inverter22after being damped by the left side wall14. Thus, according to the driving device10of the present embodiment, compared to the technology of the related art in which the inverter22is directly fixed to the cover21, vibration transmitted from the supporting mount50L to the inverter22can be reduced.

Second Example

A driving device10A of a second example will be described with reference toFIG.3. The driving device10A of the second example differs in the arrangement of the motor unit40and the gear unit30from the driving device10of the first example. Specifically; in the driving device10A of the second example, the inverter unit20, the motor unit40, and the gear unit30are arranged in this order from the left side along an axial direction (that is, right and left direction) parallel to the rotation axis A1. Further, in the driving device10A of the present example, the motor42is located between the gear unit30and the inverter22. Also, in the driving device10A of the present example, the inverter22is fixed to the left side wall14of the casing11from the outside of the casing11. Therefore, similarly to the driving device10of the first example, vibration transmitted from the supporting mount50L to the inverter22can be reduced. In the second example, in addition to the units20,30, and40, it is possible to arrange other members between the units20,30, and40, similar to the configuration described in the first example.

Third Example

A driving device10B of a third example will be described with reference toFIG.4.FIG.4illustrates a plan view of the driving device10B of the third example. The driving device10B of the third example is arranged in a front component3(seeFIG.1) of an electric vehicle100B unlike the driving device10of the first example. A driving device10B of the third example includes a motor unit40F and a gear unit30F, and drives the front wheels4F (seeFIG.1) via the front drive shaft5F. The motor unit40F has a motor42F, and the gear unit30F has a link gear32F and a differential gear34F. The structure of the motor unit40F is similar to that of the motor unit40of the first example. The structure of the gear unit30F is similar to that of the gear unit30of the first example.

The driving device10B of the third example is fixed to a floor surface of the front component3, that is, a floor panel9C by a left mount52L, a left bracket62L, the bolts B1, and a plurality of bolts B3from the left side. Further, the driving device10B of the present example is fixed to the floor panel9C by a right mount52R, a right bracket62R, the bolts B1, and the bolts B3from the right side.

In the driving device10B of the third example, an inverter unit20F is arranged in front of the driving device10B. That is, the inverter unit20F is not arranged along an axial direction parallel to the motor unit40F, the gear unit30F, and a rotation axis A2of the motor42F. The inverter unit20F is fixed by the bolts B2to a front wall14F of a casing11F of the driving device10B. The front wall14F extends along the rotation axis A2of the motor42F, unlike the left side wall14of the first example.

Further, in the driving device10B of the third example, unlike the driving device10of the first example described above, the front wall14F is composed of a casing of the motor unit40F and a casing of the gear unit30F. Therefore, the inverter unit20is fixed to the front wall14F across the motor unit40F and the gear unit30F.

Further, the compressor70is fixed to a cover21F by a bracket64F and the bolts B1. The compressor70is located in front of the driving device10B. The compressor70faces a front surface of the front wall14F.

The compressor70compresses and expands the heat medium by reciprocating a piston (not illustrated). Therefore, the compressor70is a vibration generating member that generates vibration when operated.

As illustrated inFIG.4, in the driving device10B of the present example, the compressor70is connected to the cover21F via the bracket64F. Therefore, the vibration of the compressor70is transmitted to the driving device10B through the bracket64F. However, in the driving device10B, an inverter22F of the inverter unit20F is fixed not to the cover21F but to the front wall14F of the casing11F by the bolts B2. Therefore, the vibration transmitted from the compressor70to the inverter22F can be reduced compared to the technology of the related art in which the inverter22F is fixed to the cover21F. Also, by fixing the compressor70to the driving device10B via the bracket64F, it is possible to reduce restrictions on layout of devices accommodated in the front component3.

Fourth Example

A driving device10C of a fourth example will be described with reference toFIG.5. The driving device10C of the fourth example is arranged in a front component3C of a hybrid vehicle100C, unlike the driving devices10,10A, and10B of the examples described above. The hybrid vehicle100C includes an engine80.

Also, unlike the driving device10B of the third example, the driving device10C of the present example does not have the gear unit30F. Therefore, a motor42C of a motor unit40C is directly connected to the front drive shaft5F inside a casing11C. Further, the engine80is arranged on the left side of the driving device10C. That is, the motor42C and the engine80are arranged along an axial direction (that is, right and left direction) parallel to a rotation axis A3of the motor42C. In addition, in a modification example, a gear unit may be provided between the motor unit40C and the engine80.

Further, an accommodation space S1is provided in a front part of the casing11C of the driving device10C of the present example. The accommodation space S1is a recess provided in the front part of the casing11C, and the front is open. A bottom wall14C of the accommodation space S1extends in the right and left direction along the rotation axis A3of the motor42C.

An inverter22C is arranged in the accommodation space S1. The inverter22C is fixed to the bottom wall14C of the accommodation space S1by the bolts B2from the front side of the bottom wall14C. Further, the cover21C is fixed to a front surface of the casing11C by the bolts B2. The cover21C is a flat board member extending parallel to the bottom wall14C of the accommodation space S1. The cover21C is a lid that closes the accommodation space S1. The cover21C covers the inverter22C arranged in the accommodation space S1.

The cover21C is fixed to a floor surface of the front component3C, that is, a floor panel9C via a bracket64C. Further, the engine80is fixed to the floor panel9C by a left bracket62L the bolts B1, and the bolts B3from the left side. The driving device10C is fixed to the floor panel9C by a right bracket62R, the bolts B1, and the bolts B3from the right side.

Thus, the driving device10C of the present example is fixed to the floor panel9C by a pair of brackets62L,62R in the right and left direction, and is fixed to the floor panel9C by the bracket64C from the front. Therefore, the driving device10C is fixed to the floor panel9C more firmly than in a configuration in which the driving device10C is fixed only in the right and left direction.

Also, vibration of the floor panel9C is transmitted to the cover21C via the bracket64C. However, in the driving device10C, the inverter22C is fixed not to the cover21C but to the bottom wall14C of the accommodation space S1of the casing11C by the bolts B2. Therefore, the vibration transmitted from the floor panel9C to the inverter22C can be reduced as compared with the technology of the related art in which the inverter22C is fixed to the cover21C. In the present example, the floor panel9C is an example of a “constituent member”.

Fifth Example

A driving device10D of a fifth example will be described with reference toFIG.6. The driving device10D of the fifth example differs from the driving device10A of the second example in the configuration of the casing11D. The casing11D of the driving device10D of the present example has a motor casing15D and a gear casing12D. The motor casing15D accommodates the motor42. In addition to a left side wall14D, the motor casing15D further has an extension wall16D extending leftward beyond the left side wall14D. The extension wall16D covers the inverter22of the inverter unit20from above and below. An opening17D is provided at a left end of the motor casing15D. The opening17D allows communication between the inside of the casing11D in which the inverter22is accommodated and the outside of the casing11D.

The opening17D of the motor casing15D is covered with a cover21D. That is, the cover21D covers the inverter22. The cover21D has a seat portion28D extending leftward. The seat portion28D is fixed to a supporting mount54L by bolts B4. Thus, the cover21D of the present example is fixed to the supporting mount54L via the seat portion28D of the cover21D. In a modification example, the cover21D may be directly fixed to the supporting mount54L or fixed to the vehicle body2without passing through the seat portion28D.

The gear casing12D is fixed to the motor casing15D with a plurality of bolts B5. That is, the gear casing12D and the motor casing15D are fastened together. Further, a sealing member19is provided at the boundary between the casings12D,15D. The sealing member19may be, for example, an O-ring. By utilizing the sealing member19to seal a space inside the gear casing12D, it is possible to prevent a lubricant used for smooth rotation of each of the gears32,33, and34from leaking out of the gear casing12D. Thus, in the present example, the casing11D is composed of two casings, the gear casing12D and the motor casing15D. That is, in the present example, the motor casing15D is an example of the “first casing”, and the gear casing12D is an example of the “second casing”. In a modification example, casings12D,15D may be fixed to each other with an adhesive or welded.

Like the cover21D, the gear casing12D also has a seat portion13D. The seat portion13D is fixed to the supporting mount54R with the bolts B4. Also, in the driving device10D of the present example, the inverter22is fixed to the left side wall14D of the motor casing15D from the outside. Therefore, similarly to the driving device10of the first example, vibration transmitted from the supporting mount54L to the inverter22can be reduced.

Although specific examples according to the technology of the present disclosure are described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

The technical elements described in the present disclosure exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims as of the filing. In addition, the technology exemplified in the present disclosure can achieve multiple purposes at the same time, and achieving one of them has technical utility in itself.