Traction powertrain lubrication systems

Abstract

The mobile machine (100) may include a traction powertrain (124) configured to operate on electric power and including a traction motor (130) coupled to a transmission (132). To lubricate the transmission (132), the mobile machine (100) may include a lubrication system (160) having a lubricant pump (162) coupled to a pump motor (172). The traction motor (130) and the pump motor (172) are electrically arranged in parallel with each other. A powertrain sensor monitors rotational motion within the traction powertrain (124), and the electronic controller (180) may generate a lubricant supply command instructing the lubricant pump (162) to supply a first quantity of lubricant to the transmission (132).

Description

[Technical Field]

[0001] This patent disclosure relates generally to electric traction powertrains that couple a traction motor to a propulsion device, and more particularly to a lubrication system for supplying lubricating oil to a transmission within a traction powertrain. [Background technology]

[0002] Mobile machines, such as construction and mining equipment, typically have a powertrain that includes components that generate and transmit power or torque from a prime mover to a point of use, such as wheels or tracks, to propel the mobile machine. Powertrain components may include driveshafts, transmissions, differentials, power takeoffs, and other features for transmitting rotational power. Some of these components, such as those that include parts that move relative to one another, may require liquid lubricants to aid in proper operation. As such, a mobile machine's powertrain may be operatively associated with a lubrication system that provides liquid lubricants to components, such as a transmission, that can adjust or change the torque and speed characteristics of the transmitted power output.

[0003] In conventional mobile machines, the prime mover that generates and transmits power to the powertrain is typically an internal combustion engine capable of burning hydrocarbon fuel and converting its chemical energy into mechanical power. In this configuration, the mechanical power generated by the engine may also be used to power one or more fluid pumps associated with a lubrication system that pressurizes and delivers lubricating oil to the powertrain components. However, some mobile machines may utilize electricity as a power source instead of an internal combustion engine. Electric power may be provided by a battery or generator and transmitted to a traction motor operably coupled to a propulsion device. Even electrically powered mobile machines may still include various mechanical powertrain components, such as a transmission, that require lubrication for proper operation. This disclosure relates to a lubrication system and method for supplying lubricating oil to electrically operated traction powertrain components in a lubrication system where there is no internal combustion engine providing mechanical power or torque. Summary of the Invention

[0004] In one aspect, the present disclosure describes a mobile machine including a traction powertrain configured to operate on electric power. The powertrain includes a traction motor for converting electric power into rotational motion. The traction powertrain further includes a transmission coupled to the traction motor at a transmission input and coupled to a propulsion device of the mobile machine at a transmission output. A lubrication system is installed on the mobile machine to supply lubricant to the transmission. The system includes a lubricant pump configured to pressurize liquid lubricant, the pump operatively connected to a pump motor. A powertrain sensor is operatively associated with the traction powertrain to sense rotational motion within the traction powertrain. The sensor is configured to generate and transmit a powertrain rotation signal to an electronic controller. The electronic controller is associated with the lubrication system and is programmed to generate and communicate a first lubricant supply command indicating a first lubricant quantity to the lubrication system instructing the lubricant pump to supply a first lubricant quantity to the transmission.

[0005] In another aspect, the present disclosure describes a method of operating an electrically operated traction powertrain, where rotational motion is transmitted through the traction powertrain by a traction motor operably coupled to a transmission input of a transmission to a propulsion device operably connected to a transmission output of the transmission. A powertrain sensor is used to monitor rotational motion within the traction powertrain and is operable to generate a powertrain rotation signal upon sensing rotational motion within the traction powertrain. A first lubricant supply command is generated in response to the powertrain rotation signal indicative of a first lubricant quantity for supplying a first lubricant quantity to the transmission with a lubricant supply pump. [Brief explanation of the drawings]

[0006] [Figure 1]FIG. 1 is a side view of a mobile machine, such as a wheel loader, including an electric traction powertrain for transmitting power to multiple propulsion units. [Figure 2] FIG. 2 is a schematic diagram of a lubrication system operatively associated with a pump powertrain in a parallel arrangement with a traction powertrain of a mobile machine. [Figure 3] FIG. 3 is a flow diagram of a possible method, such as a routine, process, or series of steps, that a lubrication system may implement to provide a quantity of lubricant to components of a traction powertrain. [Figure 4] FIG. 4 is an alternative embodiment of the flow diagram of FIG. 3 configured to provide a constant amount of lubricant to traction power train components when the mobile machine is coasting. [Figure 5] FIG. 5 is another embodiment of the flow diagram of FIG. 3 configured to provide a fixed amount of lubricant to the traction powertrain components that may take into account or accommodate the operating settings of the traction powertrain. DETAILED DESCRIPTION OF THE INVENTION

[0007] Referring now to the drawings, FIG. 1 illustrates a mobile machine 100 in a wheel loader embodiment that can move or load materials such as rock, soil, or rubble, with like reference numbers referring to like features wherever possible. The mobile machine 100 in a wheel loader embodiment can include a machine frame 102 supported on a plurality of propulsion units 104 that contact the ground or another work surface 105. The propulsion units 104 can receive power to propel the mobile machine 100 across the work surface 105. Examples of suitable propulsion units 104 include wheels or tracks. To change direction of travel, the machine frame 102 can be an articulated frame that includes a forward frame end 106 and a rear frame end 108 that are interconnected by an articulation joint 110 that allows the forward frame end 106 and the rear frame end 108 to articulate or pivot relative to one another. A work implement, such as a loading mechanism 112, can be positioned on the forward frame end 106 and can be lowered and raised relative to the work surface 105. The loading mechanism 112 may include one or more elongated lift arms 114 pivotally coupled at a proximal end to the forward frame end 106 and connected at another distal end to a bucket 116 for receiving material. To pivotally move the lift arms 114, the loading mechanism 112 may be operatively associated with one or more hydraulic actuators 118, such as hydraulic cylinders that may be telescopically extended and retracted by actuation of pressurized hydraulic fluid.

[0008] To accommodate an operator, an elevated cab or operator station 120 may be supported on the rear frame end 108 of the machine frame 102 in a position that provides visibility over the work surface 105. The operator station 120 may also be equipped with various controls and gauges for operating the mobile machine 100, such as a steering wheel, joystick, gear stick, speedometer, etc. In other embodiments, the mobile machine 100 may be configured for teleoperation or autonomous or semi-autonomous operation. While the mobile machine 100 of FIG. 1 is a wheel loader, aspects of the present disclosure are applicable to other types of machines used in construction, mining, or agriculture, such as haul trucks, motor graders, excavators, bulldozers, etc., which may include work implements other than the loading mechanism 112 (e.g., cranes, dump bodies, dozer blades, buckets, etc.).

[0009] To generate the electrical power necessary to operate the mobile machine 100 (e.g., drive the propulsion units), a prime mover acting as an energy source may be located on the aft frame end 108. In accordance with the present disclosure, the prime mover may be an electrical power source 122. The electrical power source 122 may be any suitable source of electrical energy capable of providing and supplying power to a load in the form of current and voltage. The electrical power source 122 may generate either direct current or alternating current electrical power, and the alternating current may be single-phase or poly-phase electricity. The electrical power source 122 may generate electrical power utilizing any suitable technology, with operating principles including electromagnetic, thermodynamic, chemical, solar, etc.

[0010] The power source 122 may be operatively associated with or part of a powertrain to operatively couple the power source 122 to an electrical load on the mobile machine that converts power to work. A powertrain may include electrical and mechanical devices that serve to transfer power and energy between a prime mover, such as a power source, and a load corresponding to a point of application. For example, the mobile machine 100 may include a traction powertrain 124 to send power to the propulsion units 104 that provide traction and mobility for the work surface 105. The power source 122 may operatively function as the start or initial point of the traction powertrain 124, and the propulsion units 104 may operatively function as the end point of the traction powertrain 124. Thus, the traction powertrain 124 is partially electric.

[0011] In addition to the electrical power source 122, the traction powertrain 124 may be associated with additional prime movers as sources of energy and power for the mobile machine. Examples of additional prime movers include an internal combustion engine 126. The internal combustion engine 126 combusts a hydrocarbon-based fuel and converts the chemical energy to generate rotational power or torque that the mobile machine 100 can use for other work. Examples of suitable fuels include diesel, gasoline, natural gas, biofuels, etc. In addition to the internal combustion engine 126, other types of prime movers that may be used with the mobile machine 100 include various types of engines, turbines, and other power generating devices.

[0012] In one embodiment, the power source 122 may be a generator coupled to the output shaft of the internal combustion engine 126 and receiving power in the form of rotational torque. A generator converts power, embodied as rotational motion, into electrical power in the form of alternating current. Specifically, a generator is an electromagnetic assembly in which permanent magnets or conductive field windings generate a magnetic field that rotates relative to induction windings, in which electrical current is generated. An advantage of utilizing the power source 122 as a prime mover in the traction powertrain 124 is that it facilitates the transmission and distribution of electrical power to the mobile machine 100 via one or more conductive circuits 128. For example, the conductive circuits 128 may transmit electrical power proximate the propulsion units 104. To convert the electrical power generated by the power source 122 into rotational motion and torque usable by the propulsion units 104, the electric traction powertrain 124 may include a traction motor 130 electrically connected to the power source 122. The traction motor 130 is an electromagnetic assembly in which electrical current flows through conductive windings, generating a rotating magnetic field. The magnetic field can attract permanent magnets or magnetic material disposed on the rotor, causing the rotor to rotate by following the rotation of the magnetic field, and the resulting rotational motion is output from a shaft extending from the traction motor 130.

[0013] The traction powertrain 124 may include additional mechanical components operatively connecting the traction motor 130 with the propulsion unit 104. For example, the traction powertrain 124 may include a transmission 132 to selectively adjust the rotational speed and / or direction output from the traction motor 130. The transmission 132 is coupled to the output shaft of the traction motor 130 via a transmission input 134 and receives the rotational motion and associated torque. The adjusted rotational motion may be output from the transmission 132 by a transmission output 136, such as a splined shaft. In embodiments where the mobile machine is a wheel loader, the transmission output 136 may be operatively connected to a forward drive shaft 138 and a rear drive shaft 134 to complete the transmission of the rotational motion and torque to the propulsion unit 104. The traction powertrain 124 may also include a differential and axles for redirecting and transmitting the rotational motion and torque in response to wheels or other propulsion units.

[0014] In addition to generating and providing electrical power to the propulsion units 104 via the traction powertrain 124, the electrical power source 122 can be used to power other systems on the mobile machine 100. For example, in a wheel loader embodiment having a lift mechanism 114 that can be raised and lowered relative to the work surface 105, the mobile machine 100 can include a hydraulic system 140 for providing pressurized hydraulic fluid to the hydraulic actuators 118. The hydraulic system 140 can include a tank or reservoir 142 and one or more hydraulic pumps 144 that are electrically powered and electrically connected to and receive power from the power source 122. The hydraulic pumps 144 can pressurize and deliver hydraulic fluid to the hydraulic actuators 118 via suitable conduits, such as flexible hoses or rigid pipes. In addition to supplying hydraulic fluid to the actuators, the hydraulic system can provide hydraulic fluid as a power source and / or as a lubricant for other systems and devices associated with the mobile machine 100.

[0015] Referring to FIG. 2 , a further embodiment of an electric traction powertrain 124 in parallel operation with other systems of the mobile machine 100 is illustrated schematically. In this embodiment, electrical power can be generated by a power source 122, which powers the traction powertrain 124, and can have any suitable design and operating principle. For example, the power source can be a generator 150, similar to a motor with an electromagnetic assembly that converts kinetic energy into electrical power in the form of alternating current. Specifically, the generator 150 is an electromagnetic assembly in which permanent magnets or conductive field windings generate a magnetic field that rotates relative to induction windings, which generate electrical current. In another example, the power source 122 can be a battery 152 that generates direct current through an electrochemical reaction. In yet another example, the power source can be a fuel cell 153 that converts chemical energy from a fuel into electrical energy. In other examples, the power source 122 can be configured as a hybrid system that uses energy from both electrical and mechanical sources.

[0016] Electrical power generated by the power source 122 is transmitted to different application points by a conductive circuit 128, which may include conductive wires, power cables, etc. If the power source 122 generates direct current, a power converter 154 may be included as part of the electric traction powertrain 124 to convert the direct current to alternating current with periodically alternating polarity for more efficient utilization by the traction motors 130. The frequency of the alternating current from the power converter 154 may determine the operating speed of the traction motors 130. The traction powertrain 124 may include other electrical devices, such as voltage converters and transformers, to further condition the power transmitted within the conductive circuit 128.

[0017] In one embodiment, the transmission 132 may include multiple inter-engageable gears 156 that can be selectively engaged and disengaged at various gear ratios to adjust the rotational speed and torque output from the traction motor 130. As one skilled in the art will appreciate, a change in rotational speed, measured in, for example, RPM, results in an inverse change in torque, measured in, for example, foot-pounds. The engageable gears 156 may have different diameters and different numbers of teeth protruding from their circumferences. The diameters and number of teeth are such that when two different engageable gears 156 mesh, they rotate at different rotational speeds. The transmission 132 may be configured with any suitable number of predetermined or fixed gear pairs of engageable gears 156 that represent different speed ratios of adjusted rotational speeds between the rotational speeds at the transmission input 134 and the transmission output 136. The transmission 132 may also be arranged to reverse the rotational motion, for example, to move the mobile machine 100 forward or backward. The transmission 132 may include a clutch or the like that disengages the transmission input 134 from the transmission output 136 and places the transmission 132 in a neutral setting so that no torque or rotational force is transmitted. In other embodiments, the transmission 132 may be an infinitely variable transmission that continuously regulates rotational motion using, for example, planetary gears. The transmission 132 may be operatively associated with a gear selector 158, such as a gear shift, to allow an operator to selectively engage multiple engageable gears 156.

[0018] The meshing, engageable gears 156 of the transmission 132 rotate in contact, thereby providing a liquid lubricant to the transmission, helping to reduce friction and wear between the gears. Accordingly, the transmission 132 may be operatively associated with a lubrication system 160 having a lubricant pump 162 and a lubricant reservoir 164. The lubricant reservoir 164 may be a vented or sealed tank containing liquid lubricant that the lubricant pump 162 can pressurize and deliver to the transmission 132 through a conduit, such as flexible tubing or rigid pipe. The lubricant pump 162 may be any suitable type of mechanical fluid pump, such as a gear pump capable of generating a pressurized flow of fluid. The lubricant pump 162 may have the same or different structure and operational design as the hydraulic pump 144 for the lift mechanism or other work implement described above. In one embodiment, in addition to the lubricant pump 162 and the hydraulic pump 144, there may be additional fluid pumps to supply hydraulic fluid to other systems of the mobile machine, such as a brake pump 166 and a steering oil pump 168.

[0019] To power the lubricant pump 162 and other pumps, the mobile machine 100 may include a pump powertrain 170 in addition to the traction powertrain 124. The pump powertrain 170 may be arranged in parallel with the traction powertrain 124 and configured to transmit electrical or mechanical power in the form of rotational torque. For example, the pump powertrain 170 may include a pump motor 172 operatively associated with the lubrication system 160. The pump motor 172 is an electromechanical device that converts electrical power into rotational motion and torque. In the illustrated embodiment, a pump gearbox 174 may be included to distribute the rotational power output from the pump motor 172 to multiple rotational outputs of multiple pumps. The pump gearbox 174 may be operably coupled to the lubricant pump 162, the brake pump 166, the steering oil pump 168, etc., and distribute the rotational motion and torque thereto via multiple shafts and clutches, for example. In other embodiments, the pump motor 172 may be directly coupled to the lubricant pump 162.

[0020] To provide power for operation, the pump motor 172 may be electrically connected or associated in common with the power source 122 that provides power to the traction motor 130. For example, the pump motor 172 may be connected to the battery 152 through a second conductive circuit 176. A second power converter 178 or similar electrical device may be disposed within the second conductive circuit 176 to modulate or regulate the power delivered to the pump motor 172.

[0021] In the illustrated embodiment, the traction motor 130 operably coupled to the transmission 132 is physically separate and distinct from the pump motor 172 associated with the lubrication system 160. More specifically, the traction motor 130 and the pump motor 172 are arranged in parallel with the first conductive circuit 128 and the second conductive circuit 176 forming a parallel electrical circuit. Thus, the traction motor 130, which operates and controls the angular velocity of the rotational motion transmitted to the transmission input 134 of the transmission 132, and the pump motor 172, which operates the lubricant pump 162, are operatively separated from one another. Relatedly, operating conditions within the transmission 132 have no direct relationship or association with the pump motor 172, which operates the lubricant pump 162. In other words, without a direct mechanical linkage between the lubrication system 160 and the traction powertrain 124, the lubricant pump 162 would not be able to directly respond to operating conditions within the transmission 132 (including the rotational motion transmitted therethrough), potentially starving the transmission of lubricant when needed. Additionally, traction motor 130 and its associated power converter 154, and pump motor 172 and its associated power converter 178 may be configured to respond differently at different angular velocities.

[0022] Thus, the lubrication system 160 may be arranged to coordinate or synchronize operation between the pump motor 172 associated with the lubricant pump 162 and the transmission 132 operatively coupled to the traction motor 130. To facilitate controlled coordination between the systems, the lubrication system 160 may be operatively associated with an electronic controller 180, also referred to as an electronic control module (ECM) or electronic control unit (ECU). The electronic controller 180 may include various circuit components in any suitable computer architecture for receiving and processing data and software. The electronic controller 180 may process and execute different functions, steps, routines, and instructions written as a computer-readable software program and may use data from sources such as data tables, charts, data maps, look-up tables, and the like. Additionally, the electronic controller 180 may be responsible for handling functions associated with various other systems on the mobile machine. While the electronic controller 180 is illustrated as a standalone device, its functionality may be distributed among several different, separate components.

[0023] For example, the electronic controller 180 may include one or more microprocessors 182, such as a central processing unit (CPU), application-specific integrated circuit (ASIC), or field-programmable gate array (FPGA), which include a plurality of transistors and similar circuits capable of reading, manipulating, and outputting data in electronic form. The electronic controller 180 may include non-transitory programmable memory 184 or other data storage capabilities, which may be random-access memory or a more permanent, non-volatile form of data storage medium. Common examples of computer-readable memory 184 include RAM, PROM, EPROM, FLASH-EPROM, and other memory chips or cartridges. The memory may store programming instructions and data in software form that can be read and processed by the microprocessor 182. The software and data may take the form of instruction sets, programs, applications, routines, libraries, databases, look-up tables, data sets, etc. The electronic controller 180 may include various input / output ports 186 and associated circuitry for communicating with other equipment and actuators associated with the traction motor 130 and / or lubrication system 160. Communications may be established by sending and receiving digital or analog signals over electronic communications lines or buses using any suitable data communications protocol, including wireless protocols. Various communication and command channels are shown by dashed lines for illustrative purposes.

[0024] For example, electronic controller 180 may be in electronic communication with one or more powertrain sensors, measurement devices, or controls operatively associated with traction powertrain 124. For example, a transmission input sensor 190 may be operatively associated with transmission input 134 to determine the input to transmission 132. Transmission input sensor 190 may be a rotational sensor, such as a rotary encoder, that senses rotational motion input to transmission 132. Transmission input sensor 190 may also be configured to sense angular velocity, i.e., the rotational speed in RPM associated with the rotational motion. Transmission input sensor 190 may be in tangential contact with a splined shaft associated with transmission input 134 to rotate therewith and may electronically communicate the angular velocity in RPM to electronic controller 180. In other embodiments, transmission input sensor 190 may be a more complex sensor and may be capable of estimating torque or rotational power input to transmission 132. A transmission output sensor 192 of similar design may be operatively associated with the transmission output 136 and in electronic communication with the electronic controller 180 to determine the output of the transmission 132 .

[0025] A motor rotation sensor 194 may be operatively associated with the traction motor 130 and in electronic communication with the electronic controller 180 to sense whether the traction motor 130 is generating rotational motion or torque. In one embodiment, the motor rotation sensor 194 may be another rotational sensor, such as a rotary encoder, that directly senses the rotational output of the traction motor 130. In other embodiments, the motor rotation sensor 194 may indirectly measure the rotational output of the traction motor 130. For example, the motor rotation sensor 194 may measure an electrical characteristic or operation of the traction motor 130, such as voltage or current draw, to infer or estimate the mechanical performance output by the traction motor. The motor rotation sensor 194 may measure the rotational motion associated with the traction motor 130 in terms of angular velocity and torque.

[0026] A selected gear sensor 196 may be associated with a gear selector 158, such as a gear stick, to evaluate or determine the operating setting of the transmission 132. In another embodiment, the selected gear sensor 196 may be associated directly with the transmission 132 to monitor the gear ratio of the engageable gears 156 therein. The gear selector 158 may be used to select different gear ratios of the engageable gears 156 within the transmission, which determines the coordination ratio between the angular velocity and torque at the transmission input 134 and the transmission output 136. Additionally, the selected gear sensor 196 may determine whether the transmission 132 is in a neutral setting, and the transmission input sensor 190 and the transmission output sensor 192 may determine whether rotational motion or torque is being transmitted through the transmission 132. [Industrial Applicability]

[0027] With reference to FIG. 3 and with continuing reference to the previous figures, an embodiment of a method for operating an electric traction powertrain 124 according to the arrangements and embodiments described herein is illustrated. For example, the traction powertrain 124 may include a traction motor 130 operably coupled to a transmission 132. There may also be a lubrication system 160 including a lubricant pump 162 operably associated with a pump powertrain 170 to supply lubricant to the transmission 132 (and possibly other systems, not shown). The traction motor 130 for the transmission 132 and the pump motor 172 for the lubricant pump 162 are electrically arranged in parallel and included in the parallel first conductive circuit 128 and second conductive circuit 176, respectively. Additionally, the traction motor 130 and the pump motor 172 may be electrically connected to the power source 122 and receive common power therefrom. The following method may be written in a programming language and embodied as a computer software program executable by an electronic controller 180.

[0028] To transfer power to propel the mobile machine 100, electrical actuation step 200 may provide power to electrically operate the traction motors 130 to generate rotational motion and torque. The rotational motion and torque are transferred to a transmission input 134 of the transmission 132 to adjust the speed ratio or torque, and the adjusted rotational motion and torque are output from a transmission output 136 to the propulsion unit 104.

[0029] To control the lubrication system 160 and supply lubricant to the transmission 132, the electronic controller 180 monitors rotational motion transmitted through the traction powertrain 124 in a powertrain monitoring step 202. The rotational motion can be monitored at different locations along the traction powertrain 124 and can be done using any of the powertrain sensors described above, including the transmission input sensor 190, the transmission output sensor 192, and / or the motor rotation sensor 198. The powertrain sensors can further measure, for example, angular velocity in RPM associated with the rotational motion in the traction powertrain 124. In response to sensing rotational motion in the traction powertrain 124, the powertrain rotation sensor generates and transmits a powertrain rotation signal 206 to the electronic controller 180 in a signal generation step 204. The powertrain rotation signal 206 can be embodied as a digital data signal that confirms the presence of rotational motion in the traction powertrain 124.

[0030] Upon receiving the powertrain rotation signal 206, the electronic controller 180 can take action to lubricate the transmission 132. For example, in a command generation step 210, the electronic controller 180 can generate a first lubrication command 212 that instructs the lubrication system 160 to supply lubrication to the transmission 132. The first lubrication command 212 can be associated with a first lubrication amount, which can be a fixed or variable amount, and can take into account, or depend in part on, the size and design of the transmission 132. In one embodiment, the command generation step 210 can utilize a maximum measurement of rotational motion sensed by any of multiple powertrain sensors to evaluate the rotational motion within the traction powertrain 124. For example, the command generation step 210 can compare the powertrain rotation signals 206 from multiple powertrain sensors and select the maximum value to calculate the first lubrication command 212. In one embodiment, the first lubrication command 212 can be variable and proportional to the angular velocity of the rotational motion transmitted within the traction powertrain 124. For example, in an associating step 214, which may occur in conjunction with the command generating step 210, the electronic controller 180 may modify the first lubricant quantity in proportion to the angular velocity so that at faster speeds, a greater amount of lubricant is directed to the transmission 132.

[0031] The first lubricant supply command 212 may be communicated to the pump powertrain 170, and the pump operation command 218 may function in any suitable manner to cause the lubricant pump 162 to direct a desired first quantity of lubricant to the transmission 132. For example, the first lubricant supply command 212 may be received directly by the pump motor 172 and control the output speed of a pump motor operatively associated with the lubricant pump 162. In another embodiment, the lubricant pump 162 may be a variable displacement pump, and the first lubricant command 212 may adjust the displacement, and therefore the amount or volume, of lubricant pressurized and discharged by the lubricant pump 162. The transmission 132 may fluidly receive the first quantity of lubricant via a fluid conduit, such as a tube or pipe, to ensure that selectively engageable gears therein are lubricated.

[0032] 4, a further embodiment of a method for operating the traction powertrain 124 is illustrated that is configured to address specific operating conditions of the mobile machine 100, such as when the transmission 132 is in a neutral setting and the mobile machine 100 is coasting. In such a situation, the traction motor 130 is not electrically activated, in other words, it is turned off and cannot generate and transfer rotational motion and torque to the traction powertrain 124. However, if the mobile machine 100 is coasting and the propulsion unit 104 is still moving, rotational motion can still be transferred back to the traction powertrain 124. When the engageable gears 154 are still meshed or rotating freely, it is useful to ensure that fresh lubricant is supplied to and received by the transmission to reduce gear friction and wear.

[0033] Thus, in a transmission output monitoring step 220, a transmission output sensor 192 associated with the transmission output 136 monitors rotational motion present at the transmission output 136. This can occur particularly when the mobile machine is coasting, even when the traction motor 130 and transmission 132 are in a neutral setting. If the transmission output sensor 192 senses rotational motion at the transmission output 136, it can be in electronic communication with the electronic controller 180. The electronic controller generates a second lubricant supply command 224 in a signal generation step 222. The second lubricant supply command 224 is associated with a second lubricant quantity, which may be a fixed or variable amount. The second lubricant supply quantity represents a minimum or default lubricant quantity available to the transmission 132 to accommodate rotational motion during coasting and similar situations. In an operate pump step 226 , a second lubricant supply command 224 is sent from the electronic controller 180 to the pump powertrain 170 to cause the lubricant pump 162 to supply a second quantity of lubricant to the transmission 132 .

[0034] Referring to FIG. 5 , an embodiment is illustrated in which a method of operating the traction powertrain 124 takes into account the operational setting of the transmission 132. For example, a selected gear monitoring step 230 may determine which of a plurality of selectable gear ratios a plurality of engageable gears 156 in the transmission 132 is currently set or positioned in. The selected gear ratio 232 of the plurality of engageable gears 156 may affect the amount of lubricant to be delivered to the transmission 132. A particularly high gear ratio may require a greater amount of lubricant. A selected gear sensor 196 associated with the gear selector 158 may be used to perform the selected gear monitoring step 230. The selected gear ratio 232 may be communicated to the electronic controller 180, which, in another association step 234, may generate a third lubricant delivery command 236 to deliver a third amount of lubricant to the transmission 132. In further embodiments, in addition to the selected gear ratio 232, the electronic controller 180 may receive and evaluate additional inputs regarding the operational settings of the traction powertrain 124 and / or transmission 132 in the associating step 234 when evaluating and associating the third lubrication command 236 to determine the appropriate amount of lubrication for the transmission.

[0035] It should be understood that the foregoing description provides examples of the disclosed systems and techniques. However, it is contemplated that other implementations of the present disclosure may differ in detail from the foregoing examples. All references to the present disclosure or its examples are intended to refer to the specific examples discussed therein and do not imply limitations on the general disclosure. All language of distinction and disparagement regarding particular features is intended to indicate a lack of preference for those features, but does not entirely exclude such from the scope of the present disclosure unless otherwise indicated.

[0036] The recitation of ranges of values ​​herein is intended to serve as a shorthand method of referring individually to each individual value within that range, unless otherwise indicated herein, and each individual value is incorporated herein as if it were individually set forth herein. Unless otherwise indicated herein or otherwise clearly contradicted by context, all methods described herein can be performed in any suitable order.

[0037] The use of the terms "a," "an," "the," and "at least one," and similar reference words in the context of describing the present invention (particularly in the context of the claims below) should be construed to cover both the singular and the plural unless otherwise indicated herein or clearly contradicted by context. When the term "at least one" is used following a list of one or more items (e.g., at least one of A and B), it shall be construed to mean one item selected from the listed items (A or B), or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by this disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

1. A mobile machine (100), a traction powertrain (124) including a traction motor (130) configured for electrical power and for converting electrical power into rotational motion, and a transmission (132) having a transmission input (134) operably coupled to the traction motor (130) and a transmission output (136) operably coupled to a mechanical propulsion device; a lubrication system (160) including a lubricant pump configured to pressurize liquid lubricant and operably coupled to a pump motor (172); at least one powertrain sensor operatively associated with the traction powertrain (124), the at least one powertrain sensor configured to generate and transmit a powertrain rotation signal (206) upon monitoring any rotational movement within the traction powertrain (124); an electronic controller (180) operatively associated with the lubrication system (160) and in electronic communication with the at least one drivetrain sensor to receive the powertrain rotation signal (206), the electronic controller (180) being programmed to generate and communicate a first lubricant supply command (212) indicating a first lubricant quantity to the lubrication system (160) that instructs the lubricant pump (162) to deliver a first lubricant quantity to the transmission (132).

2. The mobile machine (100) of any preceding claim, wherein the traction motor (130) and the pump motor (172) receive common power from a power source (122).

3. The mobile machine (100) of claim 2, wherein the traction motor (130) and the pump motor (172) are electrically arranged in parallel.

4. The mobile machine (100) of any preceding claim, wherein the powertrain rotation signal (206) generated by a powertrain sensor is indicative of an angular velocity associated with the rotational motion transmitted by the traction powertrain (124).

5. The mobile machine (100) of claim 4, wherein the electronic controller (180) further generates the first lubricant supply command (212) indicative of a first lubricant quantity related to the angular velocity.

6. 2. The mobile machine (100) of claim 1, wherein the electronic controller (180) is further configured to receive the powertrain rotation signal (206) and is programmed to generate and communicate to the lubrication system (160) a second lubricant supply command (224) indicating a second lubricant quantity, the second lubricant quantity representing a default lubricant quantity when the transmission (132) is in a neutral setting and the mobile machine (100) is coasting.

7. 2. The mobile machine (100) of claim 1, wherein the powertrain sensor is one or more of a transmission output sensor (192) operatively associated with the transmission output (136), a transmission input sensor (190) operatively associated with the transmission input (134), and a lubricant pump (162) operatively associated with the traction motor (130).

8. 10. The mobile machine (100) of claim 1, further comprising a selected gear sensor (196) in electronic communication with the electronic controller (180), the electronic controller (180) being programmed to generate and communicate a third lubricant supply command (236) indicative of a third lubricant quantity dependent in part on a selected gear ratio (232) of the transmission (132).

9. The mobile machine (100) of any preceding claim, wherein the power source (122) is selected from the group consisting of a battery (152), a fuel cell (153), and a generator.

10. A method of operating an electrically powered traction powertrain (124) on a mobile machine (100), comprising: transmitting rotational motion through a traction powertrain (124) using a traction motor (130) operably coupled to a transmission input (134) of the transmission (132); transmitting rotational motion to a propulsion device operably coupled to a transmission output (136) of said transmission (132); monitoring rotational motion within the traction powertrain (124) with a powertrain sensor; generating a powertrain rotation signal (206) when the powertrain sensor is used to monitor rotational movement; generating a first lubricant supply command (212) in response to the powertrain rotation signal (206) indicating a first lubricant quantity for supplying the first lubricant quantity to the transmission (132); operating a lubricant pump (162) operably coupled to a pump motor (172) to supply the first quantity of lubricant to the transmission (132).

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