Patent Application
20170101000
The disclosure generally relates to a powertrain for a vehicle, and more particularly to an auxiliary electric powertrain.
A powertrain includes the main components of a device that generate power and deliver it to a location. In vehicles, such as automobiles, the powertrain may include but is not limited to a torque producing device such as an internal combustion engine or an electric motor, a geartrain or transmission, a differential, one or more axle shafts, a final drive such as a wheel, and the various elements required to connect the above noted components.
Some vehicles may be equipped with a primary powertrain and an auxiliary powertrain. For example, an automobile may be equipped with a primary powertrain that is used in all circumstances to power the front wheels of a vehicle, and an auxiliary powertrain that is used to selectively power the rear wheels of the vehicle. Such a configuration may be used to provide all wheel drive capabilities to a vehicle that would otherwise only be front wheel drive. Accordingly, the auxiliary powertrain is only engaged to power the rear wheels in certain circumstances, and is otherwise not engaged to power the rear wheels. Because the auxiliary powertrain is connected to the rear wheels, various components of the auxiliary powertrain may be rotated by the wheels when the auxiliary powertrain is not being engaged to power the rear wheels, thereby introducing various energy losses into the system in the form of friction and/or energy required to rotate the mass of the various components.
A powertrain is provided. The powertrain includes a torque producing device, and a differential coupled to the torque producing device. An axle is coupled to the differential, and includes an outer axle end rotatable about a wheel axis. A wheel bearing housing rotatably supports the outer axle end of the axle. A wheel hub is rotatably supported by the wheel bearing housing for rotation about the wheel axis. A hub actuating system is coupled to the wheel bearing housing. The hub actuating system is selectively controllable between an engaged state and a disengaged state. When disposed in the engaged state, the hub actuating system rotatably couples the wheel hub and the outer axle end together for co-rotation about the wheel axis. When the hub actuating system is disposed in the disengaged state, the hub actuating system rotatably de-couples the wheel hub and the outer axle end, to allow the wheel hub to rotate relative to the outer axle end.
An auxiliary electric powertrain is also provided. The auxiliary electric powertrain includes an electric motor, a differential coupled to the electric motor, and a gear train interconnecting the electric motor and the differential. A first axle is coupled to the differential, and includes a first outer axle end rotatable about a first wheel axis. A second axle is coupled to the differential, and includes a second outer axle end rotatable about a second wheel axis. A first wheel bearing housing rotatably supports the first outer axle end of the first axle. A second wheel bearing housing rotatably supports the second outer axle end of the second axle. A first wheel hub is rotatably supported by the first wheel bearing housing for rotation about the first wheel axis. A second wheel hub is rotatably supported by the second wheel bearing housing for rotation about the second wheel axis. A first hub actuating system is coupled to the first wheel bearing housing. The first hub actuating system is selectively controllable between an engaged state and a disengaged state. When the first hub actuating system is disposed in the engaged state, the first hub actuating system rotatably couples the first wheel hub and the first outer axle end together for co-rotation about the first wheel axis. When the first hub actuating system is disposed in the disengaged state, the first hub actuating system rotatably de-couples the first wheel hub and the first outer axle end to allow the first wheel hub to rotate relative to the first outer axle end. A second hub actuating system is coupled to the second wheel bearing housing. The second hub actuating system is selectively controllable between an engaged state and a disengaged state. When the second hub actuating system is disposed in the engaged state, the second hub actuating system rotatably couples the second wheel hub and the second outer axle end together for co-rotation about the second wheel axis. When the second hub actuating system is disposed in the disengaged state, the second hub actuating system rotatably de-couples the second wheel hub and the second outer axle end to allow the second wheel hub to rotate relative to the second outer axle end.
An axle end assembly is also provided. The axle end assembly includes a wheel bearing housing, and a wheel hub rotatably supported by the wheel bearing housing for rotation about a wheel axis. At least one wheel bearing interconnects and rotatably supports the wheel hub relative to the wheel bearing housing. The axle assembly further includes an outer axle end, and a hub actuating system. The hub actuating system includes an actuator housing attached to the wheel bearing housing. The actuator housing of the hub actuating system interconnects the wheel bearing housing and the outer axle end, and rotatably supports the outer axle end for rotation about the wheel axis. At least one axle bearing interconnects and rotatably supports the outer axle end relative to the actuator housing of the hub actuating system.
Accordingly, the powertrain may be configured as the auxiliary electric powertrain, and include the axle assembly noted above. The hub actuating system at each wheel hub connected to the powertrain may be used to disconnect the components of the powertrain from the wheel hubs, thereby eliminating energy losses and/or potential damage to the components of the powertrain caused by the wheels of the vehicle rotating the components of the powertrain when the powertrain is not being used to power the wheels. It is advantageous to disconnect the powertrain from the wheel hubs at a location that is as close to the wheel hubs as possible, in order to maximize the number and mass of components that are disconnected from the wheel hubs, and are therefore not rotated by the wheel hubs when the powertrain is not being used to power the wheels.
The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the teachings when referencing the accompanying drawings.
Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., are used descriptively for the figures, and do not represent limitations on the scope of the disclosure, as defined by the appended claims. Furthermore, the teachings may be described herein in terms of functional and/or logical block components and/or various processing steps. It should be realized that such block components may be comprised of any number of hardware, software, and/or firmware components configured to perform the specified functions.
Referring to the Figures, wherein like numerals indicate like parts throughout the several views, a vehicle is generally shown at 20 in
The teachings of the disclosure may be incorporated into either the primary powertrain 22 and/or the auxiliary powertrain 24. As shown and described herein, the relevant portions of the disclosure are incorporated into and described with reference to the auxiliary powertrain 24. Although the exemplary embodiment shows both the primary powertrain 22 and the auxiliary powertrain 24, it should be appreciated that the teachings of the disclosure do not require both the primary powertrain 22 and the auxiliary powertrain 24, and may be incorporated into a machine having only a single powertrain.
As shown in the exemplary embodiment of
The powertrain in accordance with the teachings of the disclosure is described below with reference to the auxiliary powertrain 24. The auxiliary powertrain 24 includes a torque producing device 26. As shown in
A differential 30 is coupled to the torque producing device 26, i.e., the electric motor. The differential 30 may include any typical automotive differential 30 known to those skilled in the art. The differential 30 splits the rotational input from the torque producing device 26 between a first side and a second side, and allows the first side and the second side to rotate at different rotational speeds as is known. As used herein, the adjective “first” refers to the first side of the differential 30 or a driver's side of the vehicle 20, and the adjective “second” refers to the second side of the differential 30, or a passenger's side of the vehicle 20. The terms “first” and “second” are not used to imply a number or quantity, but are rather used to designate a relative position on the vehicle 20. Features of the auxiliary powertrain 24 that are identical on both the first side and the second side are labeled with the suffix “A” to represent the first side, or the suffix “B” to represent the second side. A gear train 32 (transmission) may be used to interconnect the torque producing device 26, i.e., the electric motor, and the differential 30. The gear train 32 may be used to change the rotational speed and torque output from the torque producing device 26 as is known in the art.
Referring to
The first axle end assembly 36A and the second axle end assembly 36B are identical, and mirror images of each other. Referring to
The first axle end assembly 36A includes a first hub actuating system 48A. The first hub actuating system 48A is coupled to the first wheel bearing housing 44A, and is selectively controllable to move between an engaged state and a disengaged state. When the first hub actuating system 48A is disposed in the engaged state, the first hub actuating system 48A rotatably couples the first wheel hub 46A and the first outer axle end 40A for co-rotation together, about the first wheel axis 42A. When the first hub actuating system 48A is disposed in the disengaged state, the first hub actuating system 48A rotatably de-couples the first wheel hub 46A and the first outer axle end 40A to allow the first wheel hub 46A to rotate relative to the first outer axle end 40A, thereby disconnecting the first wheel hub 46A from the rest of the auxiliary powertrain 24.
The first hub actuating system 48A includes a first actuator housing 50A fixedly attached to the first wheel bearing housing 44A. The first actuator housing 50A may be attached to the first wheel bearing housing 44A in any suitable manner, such as with a plurality of fasteners, such as bolts, a welded connection, or alternatively, the first actuator housing 50A and the first wheel bearing housing 44A may be integrally formed together as a single manufacture.
At least one first wheel bearing interconnects and rotatably supports the first wheel hub 46A relative to the first wheel bearing housing 44A. As shown, the at least one first wheel bearing includes two wheel ball bearings 52A arranged adjacent each other along the first wheel axis 42A. The first axle end assembly 36A further includes at least one first axle bearing interconnecting and rotatably supporting the first outer axle end 40A relative to the first actuator housing 50A. As shown, the at least one first axle bearing includes an axle needle bearing 56A and an axle ball bearing 58A, arranged adjacent to each other along the first wheel axis 42A.
The first outer axle end 40A and the first wheel hub 46A are axially stacked relative to each other along the first wheel axis 42A, such that the first wheel hub 46A and the first outer axle end 40A do not radially overlap each other relative to the first wheel axis 42A. Accordingly, the first outer axle end 40A and the first wheel hub 46A are arranged end-to-end along the first wheel axis 42A, and do not overlap each other along the first wheel axis 42A.
The first hub actuating system 48A includes a first axle end dog clutch member 60A attached to the first outer axle end 40A, a first wheel end dog clutch member 62A attached to the first wheel hub 46A, and a first sliding dog clutch member 64A. The first sliding dog clutch member 64A is axially moveable along the first wheel axis 42A to change the first hub actuating system 48A between the engaged state and the disengaged state. The first sliding dog clutch member 64A is engaged with only one of the first axle end dog clutch member 60A and the first wheel end dog clutch member 62A when the first hub actuating system 48A is disposed in the disengaged state. The first sliding dog clutch member 64A is simultaneously engaged with both the first axle end dog clutch member 60A and the first wheel end dog clutch member 62A when the first hub actuating system 48A is disposed in the engaged state.
The first actuator housing 50A supports a first actuator 66A, which moves the first sliding dog clutch member 64A along the first wheel axis 42A, to change the operating state of the first hub actuating system 48A between the engaged state and the disengaged state. The first actuator 66A may include any suitable style and/or configuration of actuator, such as a pneumatic actuator, a hydraulic actuator, an electric actuator, or some other device capable of moving the first sliding dog clutch member 64A.
Referring to
The second axle end assembly 36B includes a second hub actuating system 48B. The second hub actuating system 48B is coupled to the second wheel bearing housing 44B, and is selectively controllable to move between an engaged state and a disengaged state. When the second hub actuating system 48B is disposed in the engaged state, the second hub actuating system 48B rotatably couples the second wheel hub 46B and the second outer axle end 40B for co-rotation together, about the second wheel axis 42B. When the second hub actuating system 48B is disposed in the disengaged state, the second hub actuating system 48B rotatably de-couples the second wheel hub 46B and the second outer axle end 40B to allow the second wheel hub 46B to rotate relative to the second outer axle end 40B, thereby disconnecting the second wheel hub 46B from the rest of the auxiliary powertrain 24.
The second hub actuating system 48B includes a second actuator housing 50B fixedly attached to the second wheel bearing housing 44B. The second actuator housing 50B may be attached to the second wheel bearing housing 44B in any suitable manner, such as with a plurality of fasteners, such as bolts, a welded connection, or alternatively, the second actuator housing 50B and the second wheel bearing housing 44B may be integrally formed together as a single manufacture.
At least one second wheel bearing interconnects and rotatably supports the second wheel hub 46B relative to the second wheel bearing housing 44B. As shown, the at least one second wheel bearing includes two wheel ball bearings 52B arranged adjacent to each other along the second wheel axis 42B. The second axle end assembly 36B further includes at least one second axle bearing interconnecting and rotatably supporting the second outer axle end 40B relative to the second actuator housing 50B. As shown, the at least one second axle bearing includes an axle needle bearing 56B and an axle ball bearing 58B, arranged adjacent each other along the second wheel axis 42 B.
The second outer axle end 40B and the second wheel hub 46B are axially stacked relative to each other along the second wheel axis 42B, such that the second wheel hub 46B and the second outer axle end 40B do not radially overlap each other relative to the second wheel axis 42B. Accordingly, the second outer axle end 40B and the second wheel hub 46B are arranged end-to-end along the second wheel axis 42B, and do not overlap each other along the second wheel axis 42B.
The second hub actuating system 48B includes a second axle end dog clutch member 60B attached to the second outer axle end 40B, a second wheel end dog clutch member 62B attached to the second wheel hub 46B, and a second sliding dog clutch member 64B. The second sliding dog clutch member 64B is axially moveable along the second wheel axis 42B to change the second hub actuating system 48B between the engaged state and the disengaged state. The second sliding dog clutch member 64B is engaged with only one of the second axle end dog clutch member 60B and the second wheel end dog clutch member 62B when the second hub actuating system 48B is disposed in the disengaged state. The second sliding dog clutch member 64B is simultaneously engaged with both the second axle end dog clutch member 60B and the second wheel end dog clutch member 62B when the second hub actuating system 48B is disposed in the engaged state.
The second actuator housing 50B supports a second actuator 66B, which moves the second sliding dog clutch member 64B along the second wheel axis 42B, to change the operating state of the second hub actuating system 48B between the engaged state and the disengaged state. The second actuator 66B may include any suitable style and/or configuration of an actuator, such as a pneumatic actuator, a hydraulic actuator, an electric actuator, or some other device capable of moving the second sliding dog clutch member 64B.
The configuration of the first axle end assembly 36A and the second axle end assembly 36B described above and shown in
The first hub actuating system 48A and the second hub actuating system 48B are independently operable relative to each other. Accordingly, the first hub actuating system 48A may be controlled between its respective engaged state and disengaged state when the second hub actuating system 48B is disposed in either of its respective engaged state and disengaged state. Similarly, the second hub actuating system 48B may be controlled between its respective engaged state and disengaged state when the first hub actuating system 48A is disposed in either of its respective engaged state and disengaged state. The ability to control the first hub actuating system 48A and the second hub actuating system 48B independently of each other allows for the control of the auxiliary powertrain 24 in the event that one of the first hub actuating system 48A or the second hub actuating system 48B fault to their respective engaged state. If such a fault occurs, the functioning hub actuating system may be controlled to its respective disengaged state to allow the differential 30 to freely spin, while the torque producing device 26 is disengaged, thereby protecting the torque producing device 26 from being over-spun. Alternatively, the torque producing device 26 may be engaged to provide torque to the differential 30, thereby partially slowing the rotational speed of the faulty wheel hub.
Referring to
The primary difference between the alternative embodiment of the axle end assemblies shown in
The second axle end assembly 36B is similarly configured. Referring to
The configuration of the first axle end assembly 36A and the second axle end assembly 36B described above and shown in
The detailed description and the drawings or figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed teachings have been described in detail, various alternative designs and embodiments exist for practicing the disclosure defined in the appended claims.
