A hydraulic apparatus comprising a casing (1) having arranged therein a hydraulic machine (2), a shaft (4) mounted to rotate relative to the casing (1) by means of a bearing (5), a braking system (3) having a plurality of brake disks (31, 34) configured to prevent the shaft (4) rotating relative to the casing (1) in selective manner, and a control system (6, 7) for controlling said braking disks (31, 34), the hydraulic system including an irrigation system adapted to cool said brake disks (31, 34) by means of a fluid, the irrigation system including a fluid inlet (81) and a fluid outlet (82), the hydraulic system being characterized in that the fluid inlet and outlet (81, 82) of the irrigation system define a fluid flow within the casing in which the braking system (3) is downstream from the hydraulic machine (2).

A device for hydraulically operating a drive wheel of a wellbore tractor has, in certain embodiments, at least one cam and a rotatable assembly arranged to be rotatable with respect to the cam about an axis of rotation. The rotatable assembly has at least one piston. The device also has a chamber and at least one supply port for supplying hydraulic fluid from the chamber to the piston for energizing the piston, the supply port being arranged to be moved between first and second positions relative to the cam. In the first position, the piston can connect to the supply port and be energized to impart force against the cam for producing forward rotation of the assembly. In the second position, the piston can connect to the supply port and be energized to impart force against the cam for producing reverse rotation of the assembly. Related distributor assembly, wellbore tractor, and method are also described.

A device for hydraulically operating a drive wheel of a wellbore tractor has, in certain embodiments, at least one cam and a rotatable assembly arranged to be rotatable with respect to the cam about an axis of rotation. The rotatable assembly has at least one piston. The device also has a chamber and at least one supply port for supplying hydraulic fluid from the chamber to the piston for energizing the piston, the supply port being arranged to be moved between first and second positions relative to the cam. In the first position, the piston can connect to the supply port and be energized to impart force against the cam for producing forward rotation of the assembly. In the second position, the piston can connect to the supply port and be energized to impart force against the cam for producing reverse rotation of the assembly. Related distributor assembly, wellbore tractor, and method are also described.

The arrangement comprises a hydraulic machine with at least two operating cylinders, the hydraulic machine comprising a rotor part configured to be connected to the steered wheel and a stator part having main enclosures open in a receiving interface, and a pivot device that defines a pivot axis of the stator part and has main outer orifices linked to the main enclosures of the hydraulic machine in a connection interface. The arrangement further comprises a pilot line linked to a pilot chamber which has a pilot inlet in the receiving interface and the pilot line is formed in the pivot device and extends between an outer pilot orifice present in this device and a pilot opening located in the connection interface.

The arrangement comprises a hydraulic machine with at least two operating cylinders, the hydraulic machine comprising a rotor part configured to be connected to the steered wheel and a stator part having main enclosures open in a receiving interface, and a pivot device that defines a pivot axis of the stator part and has main outer orifices linked to the main enclosures of the hydraulic machine in a connection interface. The arrangement further comprises a pilot line linked to a pilot chamber which has a pilot inlet in the receiving interface and the pilot line is formed in the pivot device and extends between an outer pilot orifice present in this device and a pilot opening located in the connection interface.

A device for hydraulically operating a drive wheel of a wellbore tractor has, in certain embodiments, at least one cam and a rotatable assembly arranged to be rotatable with respect to the cam about an axis of rotation. The rotatable assembly has at least one piston. The device also has a chamber and at least one supply port for supplying hydraulic fluid from the chamber to the piston for energizing the piston, the supply port being arranged to be moved between first and second positions relative to the cam. In the first position, the piston can connect to the supply port and be energized to impart force against the cam for producing forward rotation of the assembly. In the second position, the piston can connect to the supply port and be energized to impart force against the cam for producing reverse rotation of the assembly. Related distributor assembly, wellbore tractor, and method are also described.

A device for hydraulically operating a drive wheel of a wellbore tractor has, in certain embodiments, at least one cam and a rotatable assembly arranged to be rotatable with respect to the cam about an axis of rotation. The rotatable assembly has at least one piston. The device also has a chamber and at least one supply port for supplying hydraulic fluid from the chamber to the piston for energizing the piston, the supply port being arranged to be moved between first and second positions relative to the cam. In the first position, the piston can connect to the supply port and be energized to impart force against the cam for producing forward rotation of the assembly. In the second position, the piston can connect to the supply port and be energized to impart force against the cam for producing reverse rotation of the assembly. Related distributor assembly, wellbore tractor, and method are also described.

The machine comprises distribution ducts connected to respective ones of first, second, and third enclosures (40, 42, 44), and a cylinder-capacity selector (21) suitable for being caused to take up a large cylinder capacity configuration in which the second enclosure (42) is connected to one of the main ducts (2), while the first and third enclosures (40, 44) are connected to the other main duct (1), and a small cylinder capacity configuration in which the second and third enclosures (42, 44) are connected to said one of the main ducts (2), while the first enclosure is connected to the other main duct (1). The machine further comprises a safety valve (150) having at least a first port (56) connected to said one of the main ducts (2), and a second port (58) connected to the third enclosure (44). Said safety valve is suitable, when the cylinder-capacity selector (21) is caused to go into the large cylinder capacity, for being caused to go into a first configuration that isolates the first and second ports (56, 58) from each other, and, when the cylinder-capacity selector is caused to go into its small cylinder capacity, for being caused to go into a second configuration that interconnects the first and second ports (56, 58).

The machine comprises distribution ducts connected to respective ones of first, second, and third enclosures (40, 42, 44), and a cylinder-capacity selector (21) suitable for being caused to take up a large cylinder capacity configuration in which the second enclosure (42) is connected to one of the main ducts (2), while the first and third enclosures (40, 44) are connected to the other main duct (1), and a small cylinder capacity configuration in which the second and third enclosures (42, 44) are connected to said one of the main ducts (2), while the first enclosure is connected to the other main duct (1). The machine further comprises a safety valve (150) having at least a first port (56) connected to said one of the main ducts (2), and a second port (58) connected to the third enclosure (44). Said safety valve is suitable, when the cylinder-capacity selector (21) is caused to go into the large cylinder capacity, for being caused to go into a first configuration that isolates the first and second ports (56, 58) from each other, and, when the cylinder-capacity selector is caused to go into its small cylinder capacity, for being caused to go into a second configuration that interconnects the first and second ports (56, 58).

The devices comprises a distributor (16) that presents distribution ducts opening out into a radial distribution face (16A), and a distributor-counterpart engaged in each other in such a manner that two main enclosures (18, 20) are provided between their opposite axially-extending faces. The device comprises a cylinder-capacity selector comprising two slides (24, 26) arranged after the other in a bore (22) of the element engaged in the other, to which are connected the main enclosures (18, 20) and at least some of the distribution ducts (30, 31). The slides are able to adopt at least three distinct configurations establishing different connections between the main ducts (18, 20) and the distribution ducts via the main enclosures, in order to be able to obtain at least three distinct operating cylinder capacities.