FIELD OF THE DISCLOSURE

The present disclosure relates generally to the field of motorized machinery, and more specifically to a temperature controlled axle cooling system for a vehicle.

BACKGROUND

Work machines, for example articulated dump trucks, have several axles that can heat up during operation from braking and other heat generating tasks. Axle oil flows through the axles to lubricate and cool the axle components. The axle oil has a preferred operating temperature range for most effective use. Excessive heating of the axle oil as well as excessive cooling of the axle oil can be detrimental to the axle oil, as well as to bearings, seals and other axle components.

Many axle cooling systems will run at all times while the engine is running because the pump that drives the axle cooling system is driven off the engine. This results in constant fuel burn with an added load on the engine, and can cause unnecessary cooling of the axles when the axle oil is not up to the preferred operating temperature range. Other systems may selectively run hydraulic systems to turn the axle cooling system and off. These systems typically run the axle cooling system on multiple axles when any one axle is indicating a heated condition and therefore unnecessarily executes a cooling function on the other axles of the system that are not experiencing a heated condition. This unnecessary cooling again increases fuel consumption of the work machine and unnecessarily cools axles that are not experiencing a heated condition.

It would be desirable to have an axle cooling system that could be selectively activated per axle based on the particular temperature conditions of the individual axle.

SUMMARY

One embodiment is an axle cooling system for a vehicle that has a first axle hydraulic circuit that passes through a first axle assembly, a second axle hydraulic circuit that passes through a second axle assembly, a first pump that circulates axle oil through the first axle hydraulic circuit, a second pump that circulates axle oil through the second axle hydraulic circuit, a first temperature sensor that monitors a first axle temperature of the first axle assembly, and a second temperature sensor that monitors a second axle temperature of the second axle assembly. Wherein, the first pump and the second pump are independently controlled from one another to circulate axle oil through the corresponding first or second axle hydraulic circuit.

In one example of this embodiment, when either of the first or second temperature sensors indicate that the corresponding axle temperature is below a low axle temperature threshold, the corresponding first or second pump is deactivated. One aspect of this example includes a first axle oil filter that filters the axle oil as it circulates through the first axle hydraulic circuit, a second axle oil filter that filters the axle oil as it circulates through the second axle hydraulic circuit, a first bypass circuit that monitors a first hydraulic pressure in the first axle hydraulic circuit between the first pump and the first axle oil filter, and a second bypass circuit that monitors a second hydraulic pressure in the second axle hydraulic circuit between the second pump and the second axle oil filter. Wherein, when the first or second hydraulic pressure is less than a pressure threshold, the axle oil circulates through the corresponding first or second axle oil filter. Further wherein, when the first or second hydraulic pressure is at or above the pressure threshold, the first or second axle oil bypasses the corresponding first or second axle oil filter.

In another aspect of this example, when the first axle hydraulic circuit is a closed-loop hydraulic system, the second axle hydraulic circuit is a separate closed-loop hydraulic system, and neither the first or second axle hydraulic circuits shares hydraulic fluid with a main vehicle hydraulic system. This aspect may also have a third axle and the temperature controlled axle cooling system has a third axle hydraulic circuit that passes through the third axle, the third axle hydraulic circuit being a separate closed-loop hydraulic system, and the third axle hydraulic circuit not sharing hydraulic fluid with the main vehicle hydraulic system, a third pump that circulates axle oil through the third axle hydraulic circuit, a third axle oil cooler that cools the axle oil as it circulates through the third axle hydraulic circuit, and a third temperature sensor that monitors a third axle temperature of the third axle.

In yet another example of this embodiment, the first pump is powered by a first electric motor and the second pump is powered by a second electric motor. In one aspect of this example the first electric motor is powered when the first temperature sensor indicates that the first axle temperature is greater than a temperature threshold for a time threshold. In another aspect of this example the second electric motor is powered when the second temperature sensor indicates that the second axle temperature is greater than the temperature threshold for the time threshold.

Another embodiment is a system for cooling brakes that has a first axle assembly having a first axle hydraulic circuit, a first brake assembly positioned at least partially within the first axle assembly, a first pump that selectively circulates axle oil through the first axle hydraulic circuit, a first electric motor coupled to the first pump to selectively engage the first pump, a first temperature sensor that identifies an axle temperature of the first axle assembly, a controller in communication with the first temperature sensor and the first electric motor. In this embodiment, the controller selectively engages the first electric motor when the first temperature sensor identifies that the axle temperature is above a high temperature threshold.

In one example of this embodiment a first inverter provides electrical power to the first electric motor and the controller communicates with the first inverter to selectively power the first motor. In another example the controller selectively disengages the first electric motor when the first temperature sensor identifies that the axle temperature is below the high temperature threshold.

Yet another example of this embodiment has a second axle assembly having a second axle hydraulic circuit, a second brake assembly positioned at least partially within the second axle assembly, a second pump that selectively circulates axle oil through the second axle hydraulic circuit, a second electric motor coupled to the second pump to selectively engage the second pump, and a second temperature sensor that identifies an axle temperature of the second axle assembly. In this example, the controller selectively engages the second electric motor when the second temperature sensor identifies that the axle temperature of the second axle assembly is above the high temperature threshold. In one aspect of this example, when the first temperature sensor identifies that the axle temperature of the first axle assembly is above the high temperature threshold and the second temperature sensor identifies that the axle temperature of the second axle assembly is below the high temperature threshold the controller engages only the first electric motor to provide fluid flow through the first axle hydraulic circuit.

Another aspect of this example has a third axle assembly having a third axle hydraulic circuit, a third brake assembly positioned at least partially within the third axle assembly, a third pump that selectively circulates axle oil through the third axle hydraulic circuit, a third electric motor coupled to the third pump to selectively engage the third pump, and a third temperature sensor that identifies an axle temperature of the third axle assembly. In this aspect, the controller selectively engages the third electric motor when the third temperature sensor identifies that the axle temperature of the third axle assembly is above the high temperature threshold. In part of this aspect, the controller independently powers any one or more of the first electric motor, the second electric motor, or the third electric motor when the corresponding first temperature sensor, second temperature sensor, or third temperature sensor indicate the axle temperature of the corresponding first axle assembly, second axle assembly, or third axle assembly is above the high temperature threshold.

Yet another embodiment of this disclosure is a method for controlling an axle cooling system for a vehicle, the method includes providing a first axle assembly, a first pump that selectively provides fluid flow through a first axle hydraulic circuit, a second axle assembly, a second pump that selectively provides fluid flow through a second axle hydraulic circuit, and a controller in communication with a first temperature sensor that identifies a first axle temperature and a second temperature sensor that identifies a second axle temperature, monitoring, with the controller, the first temperature sensor to identify the first axle temperature, monitoring, with the controller, the second temperature sensor to identify the second axle temperature, comparing the first and second axle temperature to a temperature threshold, and initiating a cooling response, with the controller, in either of the first axle assembly or the second axle assembly when the corresponding first or second axle temperature is above a temperature threshold. In this embodiment, when the first axle temperature is above the temperature threshold and the second axle temperature is below the temperature threshold, the cooling response is initiated in the first axle hydraulic circuit and the cooling response is not initiated in the second axle hydraulic circuit.

One example of this embodiment includes providing a first electric motor coupled to the first pump and a second electric motor coupled to the second pump. In this example, the initiating a cooling response step comprises providing instructions from the controller to power the corresponding first or second motor to provide fluid flow through the corresponding first axle hydraulic circuit or second axle hydraulic circuit. A further part of this aspect includes providing a first inverter that selectively couples the first electric motor to an alternator and a second inverter that selectively couples the second electric motor to the alternator. In this part, the initiating a cooling response step comprises providing instructions from the controller to the first inverter and second inverter to power the corresponding first or second motor.

Another example of this embodiment includes providing a third axle assembly, a third pump that selectively provides fluid flow through a third axle hydraulic circuit, and a third temperature sensor that identifies a third axle temperature to the controller. Monitoring, with the controller, the third temperature sensor to identify the third axle temperature. Comparing the third axle temperature to the temperature threshold. Initiating the cooling response, with the controller, in the third axle assembly when the third axle temperature is above the temperature threshold. In this example, the controller only initiates the cooling response in the first, second, or third axle assembly that has a corresponding first, second, or third axle temperature that is above the temperature threshold.

