A variable capacity scroll compressor includes a fixed scroll. The fixed scroll of the compressor includes a bypass flow path configured to connect a suction unit to a compression unit, a cylinder space provided on the bypass flow path, and an on/off valve disposed to be movable back and forth in the cylinder space to open/close the bypass flow path according to a difference between a discharge pressure of the discharge unit and a suction pressure of the suction unit. Thus a capacity of the compressor may be reduced by connecting the suction unit to the compression unit under a low load condition in which a difference between a discharge pressure and a suction pressure is relatively less.

A longer-lasting, lower cost, more powerful, all metal, mud motor than the presently available progressing cavity type mud motors for drilling boreholes into the earth. A mud motor apparatus possessing one single drive shaft that turns a rotary drill bit, which apparatus is attached to a drill pipe which provides high pressure mud to the mud motor, wherein the drive shaft receives at least a first portion of its rotational torque from any high pressure mud flowing through a first hydraulic chamber within the apparatus, and receives at least a second portion of its rotational torque from any high pressure mud flowing through a second hydraulic chamber within the apparatus. A typical mud motor apparatus possesses two or more hydraulic chambers, each having its own power stroke, and return stroke, which act together in a controlled fashion to provide continuous power to a rotary drill bit.

A tip seal for scroll wraps in a scroll compressor is provided. The tip seal may include surface features to form a tortuous flow path in a seal groove of a scroll wrap. The surface features can help form one or more contraction and/or expansion areas in the tortuous flow path. The tortuous flow path can help provide resistance to fluid flow and help reduce leakage through the seal groove.

A hydraulic device comprises a rotary toroidal piston chamber having a rectangular space with a bottom, two sidewalls, and an open top. Four stationary pistons and two retractable gates for each piston are within the toroidal chamber mounted on a chamber wheel fixed to an axle on which it rotates, wherein the pistons and the gates are evenly spaced around the toroidal chamber separating the chamber into four partitions. A piston support for each piston is configured to hold the piston stationary while the piston chamber rotates. A stationary cover encircles and seals the open top of the piston chamber wherein openings through the stationary cover allow each of the piston supports to pass through and be sealed. An input port opening and an output port opening are in the stationary cover for each partition. The piston chamber rotates by reacting directly to continuous hydraulic force on the stationary pistons.

A scroll compressor is provided that can cool a fixed scroll and an orbiting scroll effectively via cooling fins. A scroll compressor includes: a fixed scroll, an orbiting scroll that performs orbiting motion with respect to the fixed scroll and is combined with the fixed scroll so as to form, with the fixed scroll, a compression space to compress fluid; cooling fins that are provided on the back of the fixed scroll; and cooling fins that are provided on the back of the orbiting scroll. The cooling fins and the cooling fins are taller in a central portion than in the circumference of the central portion.

A scroll compressor is provided, in which a balancing space may be formed on a sub frame to accommodate at least one balance weight, and an oil discharge hole may be formed on a main frame, thereby suppressing, all from being introduced into or remaining in the balancing space to minimize agitation loss due to oil agitation in the balancing space, and forming a thrust surface of the main frame adjacent to an axial center of the drive shaft to suppress axial leakage at a central portion of the orbiting scroll, reducing a size of the main frame to reduce a total weight of the compressor, facilitating a centering operation of the sub frame, and suppressing an outer diameter of the sub frame from being increased, thereby accomplishing miniaturization of the scroll compressor.

Disclosed herein is an a compressor including a main body, a fixed scroll fixed on the inside of the main body, an orbiting scroll arranged to orbit relative to the fixed scroll, a compressing chamber formed by the fixed scroll and the orbiting scroll, an oil supply hole arranged to supply oil to a contact portion formed by the fixed scroll and the orbiting scroll, and an oil groove formed on an inner side of the contact portion to be closed to an outer side of the contact portion. The oil groove is extended into the form of an arc by being rotated by about 270 degrees or more along the circumference of the fixed scroll to cover the compressing chamber from the outside of the compressing chamber to supply oil all across the area of the contact portion easier which leads to more reliable operation of the compressor.

A scroll compressor is provided that may include a casing including a rotational shaft, a first scroll rotated by rotation of the rotational shaft, the first scroll including a first head plate and a first wrap that extends from the first head plate in a first direction, and a second scroll that defines a plurality of compression chambers together with the first scroll, the second scroll including a second head plate and a second wrap that extends from the second head plate in a second direction. Each of the first and second wraps spirally may extend from an outer end toward an inner start end, and the first wrap may have a thickness greater than a thickness of the second wrap.

A variable displacement oil pump for an internal combustion engine includes a pump element to vary inside volumes of pumping chambers to suck and discharge an oil, a varying mechanism to vary a pumping volume variation quantity of the pumping chambers, with movement of a movable member such as a cam ring, an urging mechanism to urge the movable member in a direction to increase the pumping volume variation quantity, first and second control oil chambers to urge the movable member to vary the pumping volume variation quantity, and a control mechanism, such as a pilot valve, to control the supply/drainage of the oil to or from the second control oil chamber. An operation oil pressure of the movable member is set higher than an operation oil pressure of the control mechanism in a higher pressure region.

A scroll compressor (10), comprising a fixed scroll (150), a movable scroll (160) and a drive shaft (30); the scroll compressor (10) further comprises a movable scroll counterweight (40); the movable scroll counterweight (40) is configured to rotate with the drive shaft (30); and the centrifugal force of the movable scroll counterweight (40) caused by the rotation acts on the hub (162) of the movable scroll (160). The above structure can effectively reduce the impact of the centrifugal force of the movable scroll on the radial seal of a scroll component, thus achieving proper radial sealing force between the fixed scroll and the movable scroll at any rotating speed.