The invention relates to a track assembly for a tracked vehicle. Said track assembly comprises a track support beam configured to support road wheels, a drive wheel member, and a drive arrangement for drive wheel member operation and an endless track disposed around said road wheels and drive wheel member. Said drive arrangement comprises a brake arrangement for braking the drive wheel member, and a drive axle coaxially arranged relative to a centre axis of said drive wheel member for rotating said drive wheel member. Said brake arrangement is configured to be journaled in bearings in connection to a portion of the drive axle. Said brake arrangement comprises a torque arm configured to be connected to said track support beam so as to essentially prevent rotation of a brake housing of said brake arrangement about said centre axis.

Disclosed is a brake arrangement for a tracked vehicle comprising a brake housing. Said brake arrangement is journaled in bearings in connection to a drive unit driven drive axle configured to rotate a drive wheel member. Said brake arrangement comprises a set of ring shaped friction elements arranged about said drive axle and configured to be pressed together in the axial direction for providing a braking function. Said brake arrangement further comprises a ring shaped parking brake piston device coaxially arranged around said drive axle in connection to a radially outer portion of said set of friction elements. Said parking brake piston device is configured to provide pressure in the axial direction against said radially outer portion of said set of friction elements based on a parking brake action so as to press said elements together for preventing rotation of said drive axle, preventing movement of drive wheel member.

Disclosed is a brake arrangement for a tracked vehicle. The brake arrangement comprises a brake housing. Said brake arrangement is journaled in bearings in connection to a drive unit driven drive axle configured to rotate a drive wheel member. Said brake arrangement comprises a set of ring shaped friction elements arranged about said drive axle and configured to be pressed together in the axial direction for providing a braking function. Said set of friction elements comprises a first end friction element being the outermost friction element against which pressure is configured to be provided for said braking function. Said first end friction element has a thickness in the axial direction which is thicker than the remaining set of friction elements so as to facilitate distributing an even pressure on said set of friction elements when said set of friction elements are pressed together for efficient friction braking function.

Provided is a parking brake apparatus for a vehicle that allows an improvement in the ease of assembly. A parking brake apparatus includes a valve, a single hydraulic actuator that includes a cylinder, a piston housed in the cylinder in such a manner as to be reciprocably displaceable along the cylinder, and a principal brake rod connected to the piston, and can displace the piston to one of a brake operating position and a brake non-operating position by the valve, a balance arm connected to a first end portion of the principal brake rod on a side protruded from the cylinder, and a pair of left and right auxiliary brake rods provided between bent portions at end portions of the balance arm and left and right brake arms, respectively. The hydraulic actuator includes a spring member for constantly urging the piston to the brake operating position.

A bulldozer includes a steering clutch, a steering brake, a hydraulic pump that discharges a lubricating oil, a first lubricating oil supply path, a second lubricating oil supply path, a third lubricating oil supply path, and a flow amount switching valve disposed on the second lubricating oil supply path. The first lubricating oil supply path supplies a portion of the lubricating oil discharged by the hydraulic pump to the steering clutch The second lubricating oil supply path supplies a portion of the lubricating oil discharged by the hydraulic pump to the steering brake. The third lubricating oil supply path supplies, to the steering brake, a portion of the lubricating oil that has passed through the steering clutch. The flow amount switching valve switches an amount of the lubricating oil supplied to the steering brake.

A bulldozer includes a steering clutch, a steering brake, a hydraulic pump that discharges a lubricating oil, a first lubricating oil supply path, a second lubricating oil supply path, a third lubricating oil supply path, and a flow amount switching valve disposed on the second lubricating oil supply path. The first lubricating oil supply path supplies a portion of the lubricating oil discharged by the hydraulic pump to the steering clutch The second lubricating oil supply path supplies a portion of the lubricating oil discharged by the hydraulic pump to the steering brake. The third lubricating oil supply path supplies, to the steering brake, a portion of the lubricating oil that has passed through the steering clutch. The flow amount switching valve switches an amount of the lubricating oil supplied to the steering brake.

A hydraulic brake assembly (12) includes a housing (24) having first and second side-by-side bores (30), each defining a respective master cylinder assembly. Each master cylinder assembly includes a master cylinder piston (32) slidably movable by actuation of a respective brake pedal (18a, 18b) to and between an active position and an inactive position. A spool (74) slidably disposed within a piston bore (70) of the master cylinder piston (32) is operable in a first mode to direct hydraulic fluid from a quick-fill chamber (62) to a master cylinder chamber (50) at a first pressure upon initial movement of the master cylinder piston (32) from the inactive position toward the active position. The spool (74) is operable in a second mode to direct hydraulic fluid from the quick-fill chamber (62) to a tank (20) when pressure in the master cylinder chamber (50) reaches a predefined threshold.

A hydraulic brake assembly (12) includes a housing (24) having first and second side-by-side bores (30), each defining a respective master cylinder assembly. Each master cylinder assembly includes a master cylinder piston (32) slidably movable by actuation of a respective brake pedal (18a, 18b) to and between an active position and an inactive position. A spool (74) slidably disposed within a piston bore (70) of the master cylinder piston (32) is operable in a first mode to direct hydraulic fluid from a quick-fill chamber (62) to a master cylinder chamber (50) at a first pressure upon initial movement of the master cylinder piston (32) from the inactive position toward the active position. The spool (74) is operable in a second mode to direct hydraulic fluid from the quick-fill chamber (62) to a tank (20) when pressure in the master cylinder chamber (50) reaches a predefined threshold.

A braking circuit including at least an auxiliary right valve (200) and an auxiliary left valve (300) suitable to allow braking on both sides, right and left of a vehicle, when this is required, but allowing to apply a pressure braking only on one of the two sides, right or left, when this is required to provide a steering function, characterized in that the circuit further comprises a master valve (400) having two positions: a first position when the vehicle has a velocity under a threshold wherein separate and selective right or left braking is authorized and a second position when the vehicle has a velocity above said threshold wherein said master valve (400) connects both a right braking line (204, 1205) and a left braking line (304, 1305) to an output braking line (110) so that if a braking is requested both right braking line (204, 1204) and left braking line (304, 1305) are under pressure and selective right or left braking is forbidden.

A braking circuit including at least an auxiliary right valve (200) and an auxiliary left valve (300) suitable to allow braking on both sides, right and left of a vehicle, when this is required, but allowing to apply a pressure braking only on one of the two sides, right or left, when this is required to provide a steering function, characterized in that the circuit further comprises a master valve (400) having two positions: a first position when the vehicle has a velocity under a threshold wherein separate and selective right or left braking is authorized and a second position when the vehicle has a velocity above said threshold wherein said master valve (400) connects both a right braking line (204, 1205) and a left braking line (304, 1305) to an output braking line (110) so that if a braking is requested both right braking line (204, 1204) and left braking line (304, 1305) are under pressure and selective right or left braking is forbidden.