Hydraulic drive system

A high-rail wheel drive system comprising:

• at least one diverter, the at least one diverter having an off-rail drive operation position and an on-rail drive operating position;
• a hydraulic supply sub-system, the hydraulic supply sub-system including at least one fluid reservoir for providing and receiving hydraulic fluid, at least one hydraulic fluid pump for providing high pressure hydraulic fluid, at least one high pressure hydraulic fluid supply line for providing high pressure hydraulic fluid to the at least one diverter of the high-rail wheel drive system, and at least one low pressure hydraulic fluid return line for returning low pressure fluid from components of high-rail wheel drive system to the fluid reservoir from the at least one diverter;
• an off-rail drive sub-system, the off rail sub system being hydraulically coupled to the at least one diverter such that when the at least one diverter is in the off-rail drive operation position, the high pressure hydraulic fluid is provided to one or more off-rail drive component drive motors of the off-rail drive sub-system to power one or more off-rail drive components, the off rail sub system being hydraulically coupled to the at least one diverter such that when the at least one diverter is in the off-rail drive operation position, the low pressure hydraulic from the one or more off-rail drive component drive motors is returned to the fluid reservoir through the at least one diverter;
• and
• a rail wheel drive sub-system, the being hydraulically coupled to the at least one diverter such that when the at least one diverter is in the on-rail drive operation position, the high pressure hydraulic fluid is provided to rail wheel drive sub-system and low pressure hydraulic fluid from the rail wheel drive sub-system is returned to the fluid reservoir through the at least one diverter,
• the rail wheel drive sub-system comprising:
• a first drive axel;
• at least one first axel drive motor, the at least one first axel drive motor being operatively coupled to the first drive axel such that when high pressure hydraulic fluid for the at least one diverter enters the at least one first axel drive motor, the hydraulic fluid passes through the at least one first axel drive motor to power the first drive axel, the hydraulic fluid then exiting the at least one first axel drive motor as low pressure hydraulic fluid;
• a second drive axel;
• at least one second axel drive motor, the at least one second axel drive motor being operatively coupled to the second drive axel such that when high pressure hydraulic fluid from the at least on diverter enters the at least one second axel drive motor, the hydraulic fluid passes through the at least one second axel drive motor causing the second drive axel to power the second drive axel, the hydraulic fluid then exiting the at least one second axel drive motor as low pressure hydraulic fluid;
• a first counterbalance unit, the first counterbalance unit receiving high pressure hydraulic fluid from the at least one diverter, the first counterbalance unit being hydraulically coupled to the at least one first axel drive motor to provide the high pressure hydraulic fluid to the at least one first axel drive motor, the first counterbalance unit being hydraulically coupled to the at least one first axel drive motor such that the low pressure hydraulic fluid exiting the at least one first axel drive motor is passed through the first counterbalance unit to the fluid reservoir wherein,
• when high pressure hydraulic fluid is not being supplied to the at least one first axel drive motor, the first counterbalance unit restricts the flow of hydraulic fluid exiting the at least one first axel drive motor back to the fluid reservoir to provide dynamic braking to the at least one first axel drive motor when the at least one first axel drive motor is in an unpowered state;
• a second counterbalance unit, the second counterbalance unit receiving high pressure hydraulic fluid from the at least one diverter, the second counterbalance unit being hydraulically coupled to the at least one second axel drive motor to provide the high pressure hydraulic fluid to the at least one second axel drive motor, the second counterbalance unit being hydraulically coupled to the at least one second axel drive motor such that the low pressure hydraulic fluid exiting the at least one second axel drive motor is passed through the second counterbalance unit to the fluid reservoir wherein,
• when high pressure hydraulic fluid is not being supplied to the at least one second axel drive motor, the second counterbalance unit restricts the flow of hydraulic fluid exiting the at least one second axel drive motor back to the fluid reservoir to provide dynamic braking to the at least one second axel drive motor when the at least one second axel drive motor is in an unpowered state;
• a compensator unit, the compensator unit being hydraulically coupled to both the high pressure hydraulic fluid and the low pressure hydraulic fluid of the at least one first axel drive motor and the high pressure hydraulic fluid and the low pressure hydraulic fluid of the at least one second axel drive motor such that the compensator unit allows high pressure hydraulic fluid and low pressure hydraulic fluid to pass between the at least one first axel drive motor and the at least one second axel drive motor so that the pressure of the high pressure hydraulic fluid pressure and the pressure of the low pressure hydraulic fluid can be equalized between the at least one first axel drive motor and the at least one second axel drive motor;
• and
• a cavitation prevention pump, the cavitation prevention pump being operatively coupled to fluid reservoir, the cavitation prevention pump being operatively coupled to the at least one first axel drive motor such that the cavitation prevention pump provides hydraulic fluid to the at least one first axel drive motor to prevent the at least one first axel drive motor from cavitating when no high pressure hydraulic fluid is provided to the at least one first axel drive motor, the cavitation prevention pump being operatively coupled to the at least one second axel drive motor such that the cavitation prevention pump provides hydraulic fluid to the at least one second axel drive motor to prevent the at least one second axel drive motor from cavitating when no high pressure hydraulic fluid is provided to the at least one second axel drive motor.

A method comprising:

• providing a first rail wheel drive axel;
• providing at least one first rail wheel drive axel motor;
• operatively coupling the at least one first rail wheel drive axel motor to the first rail wheel drive axel such that when high pressure hydraulic fluid is to the provided first rail wheel drive axel motor, the first rail wheel drive axel motor powers the first rail wheel drive axel;
• providing a first counterbalance unit;
• hydraulically coupling the first counterbalance unit to the at least one first rail wheel drive axel motor such that when high pressure hydraulic fluid is provided to the first counterbalance unit, the first counterbalance unit provides the high pressure hydraulic fluid to the at least one first rail wheel drive axel motor, thereby powering the at least one first rail wheel drive axel motor, and such that low pressure hydraulic fluid from the at least one first rail wheel drive axel motor is provided back to the first counterbalance unit wherein,
• when high pressure hydraulic fluid is not being supplied to the at least one first rail wheel drive axel motor, the first counterbalance unit restricts the flow of hydraulic fluid exiting the at least one first axel drive motor back to the fluid reservoir to provide dynamic braking to the at least one first axel drive motor when the at least one first axel drive motor is in an unpowered state;
• providing a second rail wheel drive axel;
• providing at least one second rail wheel drive axel motor;
• operatively coupling the at least one second rail wheel drive axel motor to the second rail wheel drive axel such that when high pressure hydraulic fluid is to the provided second rail wheel drive axel motor, the second rail wheel drive axel motor powers the second rail wheel drive axel;
• providing a second counterbalance unit;
• hydraulically coupling the second counterbalance unit to the at least one second rail wheel drive axel motor such that when high pressure hydraulic fluid is provided to the second counterbalance unit, the second counterbalance unit provides the high pressure hydraulic fluid to the at least one second rail wheel drive axel motor, thereby powering the at least one second rail wheel drive axel motor, and such that low pressure hydraulic fluid from the at least one second rail wheel drive axel motor is provided back to the second counterbalance unit wherein,
• when high pressure hydraulic fluid is not being supplied to the at least one second rail wheel drive axel motor, the second counterbalance unit restricts the flow of hydraulic fluid exiting the at least one second axel drive motor back to the fluid reservoir to provide dynamic braking to the at least one second axel drive motor when the at least one second axel drive motor is in an unpowered state;
• providing a compensator unit;
• hydraulically coupling the compensator unit to the first counterbalance unit and to the second counterbalance unit such that the compensator unit allows high pressure hydraulic fluid and low pressure hydraulic fluid to pass between the at least one first axel drive motor and the at least one second axel drive motor so that the pressure of the high pressure hydraulic fluid pressure and the pressure of the low pressure hydraulic fluid can be equalized between the at least one first axel drive motor and the at least one second axel drive motor;
• providing a cavitation prevention pump;
• hydraulically coupling the cavitation prevention pump to the at least one first rail wheel drive axel motor such that the cavitation prevention pump provides hydraulic fluid to the at least one first axel drive motor to prevent the at least one first axel drive motor from cavitating when no high pressure hydraulic fluid is provided to the at least one first axel drive motor;
• hydraulically coupling the cavitation prevention pump to the at least one second rail wheel drive axel motor such that the cavitation prevention pump provides hydraulic fluid to the at least one second axel drive motor to prevent the at least one second axel drive motor from cavitating when no high pressure hydraulic fluid is provided to the at least one second axel drive motor;
• and
• providing high pressure hydraulic fluid to the first counterbalance unit and the second counterbalance unit.

A method for providing a high-rail wheel drive system comprising:

• providing at least one diverter, the at least one diverter including an off-rail drive operation position and an on-rail drive operating position;
• providing a hydraulic supply sub-system, the hydraulic supply sub-system including at least one fluid reservoir for providing and receiving hydraulic fluid, at least one hydraulic fluid pump for providing high pressure hydraulic fluid, at least one high pressure hydraulic fluid supply line for providing high pressure hydraulic fluid to the at least one diverter of the high-rail wheel drive system, and at least one low pressure hydraulic fluid return line for returning low pressure fluid from components of high-rail wheel drive system to the fluid reservoir from the at least one diverter;
• providing an off-rail drive sub-system, the off rail sub system being hydraulically coupled to the at least one diverter such that when the at least one diverter is in the off-rail drive operation position, the high pressure hydraulic fluid is provided to one or more off-rail drive component drive motors of the off-rail drive sub-system to power one or more off-rail drive components, the off rail sub system being hydraulically coupled to the at least one diverter such that when the at least one diverter is in the off-rail drive operation position, the low pressure hydraulic from the one or more off-rail drive component drive motors is returned to the fluid reservoir through the at least one diverter;
• and
• providing an on-rail wheel drive sub-system, the on-rail wheel drive sub-system being hydraulically coupled to the at least one diverter such that when the at least one diverter is in the on-rail drive operation position, the high pressure hydraulic fluid is provided to the on-rail wheel drive sub-system and low pressure hydraulic fluid from the rail wheel drive sub-system is returned to the fluid reservoir through the at least one diverter the on-rail wheel drive sub-system including:
• a first drive axel;
• at least one first axel drive motor, the at least one first axel drive motor being operatively coupled to the first drive axel such that when high pressure hydraulic fluid for the at least one diverter enters the at least one first axel drive motor, the hydraulic fluid passes through the at least one first axel drive motor to power the first drive axel, the hydraulic fluid then exiting the at least one first axel drive motor as low pressure hydraulic fluid;
• a second drive axel;
• at least one second axel drive motor, the at least one second axel drive motor being operatively coupled to the second drive axel such that when high pressure hydraulic fluid from the at least one diverter enters the at least one second axel drive motor, the hydraulic fluid passes through the at least one second axel drive motor causing the second drive axel to power the second drive axel, the hydraulic fluid then exiting the at least one second axel drive motor as low pressure hydraulic fluid;
• a first counterbalance unit, the first counterbalance unit receiving high pressure hydraulic fluid from the at least one diverter, the first counterbalance unit being hydraulically coupled to the at least one first axel drive motor to provide the high pressure hydraulic fluid to the at least one first axel drive motor, the first counterbalance unit being hydraulically coupled to the at least one first axel drive motor such that the low pressure hydraulic fluid exiting the at least one first axel drive motor is passed through the first counterbalance unit to the fluid reservoir wherein,
• when high pressure hydraulic fluid is not being supplied to the at least one first axel drive motor, the first counterbalance unit restricts the flow of hydraulic fluid exiting the at least one first axel drive motor back to the fluid reservoir to provide dynamic braking to the at least one first axel drive motor when the at least one first axel drive motor is in an unpowered state;
• a second counterbalance unit, the second counterbalance unit receiving high pressure hydraulic fluid from the at least one diverter, the second counterbalance unit being hydraulically coupled to the at least one second axel drive motor to provide the high pressure hydraulic fluid to the at least one second axel drive motor, the second counterbalance unit being hydraulically coupled to the at least one second axel drive motor such that the low pressure hydraulic fluid exiting the at least one second axel drive motor is passed through the second counterbalance unit to the fluid reservoir wherein,
• when high pressure hydraulic fluid is not being supplied to the at least one second axel drive motor, the second counterbalance unit restricts the flow of hydraulic fluid exiting the at least one second axel drive motor back to the fluid reservoir to provide dynamic braking to the at least one second axel drive motor when the at least one second axel drive motor is in an unpowered state;
• a compensator unit, the compensator unit being hydraulically coupled to both the high pressure hydraulic fluid and the low pressure hydraulic fluid of the at least one first axel drive motor and the high pressure hydraulic fluid and the low pressure hydraulic fluid of the at least one second axel drive motor such that the compensator unit allows high pressure hydraulic fluid and low pressure hydraulic fluid to pass between the at least one first axel drive motor and the at least one second axel drive motor so that the pressure of the high pressure hydraulic fluid pressure and the pressure of the low pressure hydraulic fluid can be equalized between the at least one first axel drive motor and the at least one second axel drive motor;
• and
• a cavitation prevention pump, the cavitation prevention pump being operatively coupled to fluid reservoir, the cavitation prevention pump being operatively coupled to the at least one first axel drive motor such that the cavitation prevention pump provides hydraulic fluid to the at least one first axel drive motor to prevent the at least one first axel drive motor from cavitating when no high pressure hydraulic fluid is provided to the at least one first axel drive motor, the cavitation prevention pump being operatively coupled to the at least one second axel drive motor such that the cavitation prevention pump provides hydraulic fluid to the at least one second axel drive motor to prevent the at least one second axel drive motor from cavitating when no high pressure hydraulic fluid is provided to the at least one second axel drive motor.