A working machine is disclosed. A boom supports an arm. An upper revolving body supports the boom. A lower traveling body mounts the upper revolving body in a rotatable state. A hydraulic actuator drives a hydraulic oil while relieving the hydraulic oil. A first pump supplies the hydraulic oil to the hydraulic actuator. A pump state detector detects load of the first pump. A controller reduces a flow rate of the hydraulic oil from the first pump to the hydraulic actuator when the pump state detector detects a predetermined state.

A working machine is disclosed. A boom supports an arm. An upper revolving body supports the boom. A lower traveling body mounts the upper revolving body in a rotatable state. A hydraulic actuator drives a hydraulic oil while relieving the hydraulic oil. A first pump supplies the hydraulic oil to the hydraulic actuator. A pump state detector detects load of the first pump. A controller reduces a flow rate of the hydraulic oil from the first pump to the hydraulic actuator when the pump state detector detects a predetermined state.

Sealed piston apparatus and related systems for use with vehicle torque converters are disclosed. A disclosed vehicle torque converter includes a housing and a clutch including a piston in the housing. The piston has a first side partially defining a first chamber and a second side, opposite the first side, partially defining a second chamber. The vehicle torque converter also includes a first seal operatively coupled to the piston and a second seal operatively coupled to the piston. The vehicle torque converter also includes an orifice positioned on the piston radially inward relative to a clutch pack of the clutch. The orifice is configured to provide a flow of a fluid between the first and second chambers during a lockup on operation of the vehicle torque converter to lubricate the clutch. The first seal is a one-way seal.

Sealed piston apparatus and related systems for use with vehicle torque converters are disclosed. A disclosed vehicle torque converter includes a housing and a clutch including a piston in the housing. The piston has a first side partially defining a first chamber and a second side, opposite the first side, partially defining a second chamber. The vehicle torque converter also includes a first seal operatively coupled to the piston and a second seal operatively coupled to the piston. The vehicle torque converter also includes an orifice positioned on the piston radially inward relative to a clutch pack of the clutch. The orifice is configured to provide a flow of a fluid between the first and second chambers during a lockup on operation of the vehicle torque converter to lubricate the clutch. The first seal is a one-way seal.

Sealed piston apparatus and related systems for use with vehicle torque converters are disclosed. A disclosed vehicle torque converter includes a housing and a clutch including a piston in the housing. The piston has a first side partially defining a first chamber and a second side, opposite the first side, partially defining a second chamber. The vehicle torque converter also includes a first seal operatively coupled to the piston and a second seal operatively coupled to the piston. The vehicle torque converter also includes an orifice positioned on the piston radially inward relative to a clutch pack of the clutch. The orifice is configured to provide a flow of a fluid between the first and second chambers during a lockup on operation of the vehicle torque converter to lubricate the clutch. The first seal is a one-way seal.

A clutching device of an automatic transmission may include: a clutch drum connected with a first rotation element, a clutch connected with the clutch drum and also connected with a second rotation element for selective torque delivery, and a piston unit to operate the clutch. In particular, the piston unit includes: a first piston moving toward the clutch by a hydraulic pressure; a spring retainer arranged on the first rotation element; a support drum arranged in the first piston; a second piston arranged in the support drum and moving in an axial direction of the first rotation element; a first return spring applying restoring force to the first piston; a second return spring applying restoring force to the second piston; a latch spring applying pressure to the clutch when the first piston moves toward the clutch; and a latch device selectively limiting bidirectional movement of the first piston.

A clutching device of an automatic transmission may include: a clutch drum connected with a first rotation element, a clutch connected with the clutch drum and also connected with a second rotation element for selective torque delivery, and a piston unit to operate the clutch. In particular, the piston unit includes: a first piston moving toward the clutch by a hydraulic pressure; a spring retainer arranged on the first rotation element; a support drum arranged in the first piston; a second piston arranged in the support drum and moving in an axial direction of the first rotation element; a first return spring applying restoring force to the first piston; a second return spring applying restoring force to the second piston; a latch spring applying pressure to the clutch when the first piston moves toward the clutch; and a latch device selectively limiting bidirectional movement of the first piston.

A clutching device of an automatic transmission may include: a clutch drum connected with a first rotation element, a clutch connected with the clutch drum and also connected with a second rotation element for selective torque delivery, and a piston unit to operate the clutch. In particular, the piston unit includes: a first piston moving toward the clutch by a hydraulic pressure; a spring retainer arranged on the first rotation element; a support drum arranged in the first piston; a second piston arranged in the support drum and moving in an axial direction of the first rotation element ; a first return spring applying restoring force to the first piston; a second return spring applying restoring force to the second piston; a latch spring applying pressure to the clutch when the first piston moves toward the clutch; and a latch device selectively limiting bidirectional movement of the first piston.

A clutching device of an automatic transmission may include: a clutch drum connected with a first rotation element, a clutch connected with the clutch drum and also connected with a second rotation element for selective torque delivery, and a piston unit to operate the clutch. In particular, the piston unit includes: a first piston moving toward the clutch by a hydraulic pressure; a spring retainer arranged on the first rotation element; a support drum arranged in the first piston; a second piston arranged in the support drum and moving in an axial direction of the first rotation element ; a first return spring applying restoring force to the first piston; a second return spring applying restoring force to the second piston; a latch spring applying pressure to the clutch when the first piston moves toward the clutch; and a latch device selectively limiting bidirectional movement of the first piston.

The invention relates to a downhole tool for use in a petroleum well. The downhole tool (100) comprises a first part (110) comprising a driving unit (8), and second part (120) comprising a driven unit (9), wherein the drive unit (8) is configured for driving the driven unit (9). The downhole tool (100) comprises a coupling unit (1) having an input side (S1) coupled with the driving unit (8) and an output side (S2) coupled with the driven unit (9), wherein the driving unit (8) is configured for driving the driving unit (9) via the coupling unit (1) comprising a torque limiting coupling having a first operational mode, the coupling unit (1) transfers all torque from the input side (S1) to the output side (S2), the coupling unit (1) further having a second operational mode, wherein the coupling unit (1) slips such that less torque is transferred form the input side (S1) to the output side (S2), wherein the second operational mode is automatically activated when the torque load on the input side exceeds a predefined level, and wherein the first operational mode is automatically activated when the torque load on the input side reduces to a level below a further predefined level. The coupling unit (1) comprises a displacement pump (2), wherein the displacement pump (2) is activated by opening of a pressure-limitation valve (4), for facilitating slipping of the coupling unit (1) when the coupling unit (1) is switching to the second operational mode, and wherein the displacement pump (2) is deactivated by closing of the pressure-limitation valve (4), for locking the coupling unit (1) when the coupling unit (1) is switching to the first operational mode.