Propulsion system for a construction machine

A propulsion system for a construction machine, the construction machine having at least a first compaction member, a second compaction member, a third compaction member, and a fourth compaction member associated therewith, the propulsion system comprising:

• a first hydraulic motor adapted to rotate the first compaction member;
• a second hydraulic motor adapted to rotate the second compaction member;
• a third hydraulic motor adapted to rotate the third compaction member;
• a fourth hydraulic motor adapted to rotate the fourth compaction member;
• a first hydraulic pump fluidly coupled to each of the first hydraulic motor and the second hydraulic motor via a first high pressure line and a first low pressure line, the first high pressure line adapted to allow flow of a fluid at high pressure from the first hydraulic pump to each of the first hydraulic motor and the second hydraulic motor, the first low pressure line adapted to allow flow of the fluid at low pressure from each of the first hydraulic motor and the second hydraulic motor to the first hydraulic pump;
• a second hydraulic pump fluidly coupled to each of the third hydraulic motor and the fourth hydraulic motor via a second high pressure line and a second low pressure line, the second high pressure line adapted to allow flow of a fluid at high pressure from the second hydraulic pump to each of the third hydraulic motor and the fourth hydraulic motor, the second low pressure line adapted to allow flow of the fluid at low pressure from each of the third hydraulic motor and the fourth hydraulic motor to the second hydraulic pump;
• and
• a first hydraulic valve fluidly coupled to the first low pressure line and a casing of each of the first hydraulic motor and the second hydraulic motor;
• a second hydraulic valve fluidly coupled to the second low pressure line and a casing of each of the third hydraulic motor and the fourth hydraulic motor,
• wherein each of the first hydraulic valve and the second hydraulic valve is adapted to selectively allow flow of at least a portion of the fluid at low pressure from each of the first low pressure line and the second low pressure line to the respective casings for cooling of each of the first hydraulic motor, the second hydraulic motor, the third hydraulic motor, and the fourth hydraulic motor respectively.

A method for cooling a propulsion system associated with a construction machine, the method comprising:

• providing flow of a fluid at high pressure from at least one hydraulic pump to at least one hydraulic motor;
• providing flow of the fluid at low pressure from the at least one hydraulic motor to the at least one hydraulic pump;
• bleeding, selectively, at least a portion of the fluid at low pressure to a casing of the at least one hydraulic motor;
• and
• cooling the at least one hydraulic motor using flow of at least the portion of the fluid at low pressure through the casing of the at least one hydraulic motor.