A double-headed piston type swash plate compressor includes a rotation shaft, a housing, a swash plate, two cylinder bores, a double-headed piston, and two shoes. The double-headed piston includes two shoe holders, a neck, two heads, and two coupling portions. Each of the coupling portions includes an outer portion and an inner portion. A direction orthogonal to both of an opposing direction of the inner portion and the outer portion and the axial direction of the double-headed piston is referred to as a widthwise direction. The neck is larger in the widthwise direction than in the opposing direction so that the neck is deformable in the opposing direction. Each of the two coupling portions has a width that is less than or equal to a width of the neck. The inner portion includes a narrow portion. The narrow portion is at least partially located closer to the head than the shoe holder in the inner portion. The two coupling portions are deformable in the widthwise direction when the swash plate applies load to the double-headed piston.

A piston (1) having a piston shaft (2), a ball head (3) at one end of the piston shaft (2), and a slider shoe (4) mounted to the ball head (3), wherein the ball head (3) has a through channel (5), the slider shoe (4) has a sliding surface (6) and a through hole (7) in communication with an end of the through channel (5), and a plastic material (8) is arranged in a gap between the slider shoe (4) and the ball head (3) and forms an inner coating (9) of the through hole (7). The production of such a piston should be facilitated. To this end a sealing surface (14) is arranged at the end of the through channel (5) wherein the sealing surface (14) surrounds the opening of the through channel (5) into the through bore (7) and an inner diameter of the sealing surface (14) is smaller than an inner diameter of the inner coating (9) of the through bore (7).

A swash plate compressor in which a lubricating film is not formed on a sliding contact surface of the swash plate and the piston owing to the use of the semispherical shoe. The semispherical shoe (4) is subjected to sliding contact with the swash plate of the swash plate compressor and the piston thereof. A base material (5) consists of a metallic member having a resin layer (6b) formed on a surface of a planar part (4b) that is subjected to sliding contact with the swash plate. A resin layer (6a) is formed on a surface of a spherical part (4a) to be subjected to sliding contact with the piston. The resin layer (6a) and the resin layer (6b) are integral with each other. At least one portion of the base material (5) is exposed.

A swash plate compressor according to the present invention includes a first slide layer formed between a swash plate and shoes; and a second slide layer formed between cylinder bores and pistons. The first slide layer and the second slide layer each contain binder resin and solid lubricant. The first slide layer has a smaller contact angle of lubricating oil than the second slide layer.

A double-headed piston type swash plate compressor includes a rotation shaft, a housing, a swash plate, two cylinder bores, a double-headed piston, and two shoes. The double-headed piston includes two shoe holders, a neck, two heads, and two coupling portions. Each of the coupling portions includes an outer portion and an inner portion. A direction orthogonal to both of an opposing direction of the inner portion and the outer portion and the axial direction of the double-headed piston is referred to as a widthwise direction. The neck is larger in the widthwise direction than in the opposing direction so that the neck is deformable in the opposing direction. Each of the two coupling portions has a width that is less than or equal to a width of the neck. The inner portion includes a narrow portion. The narrow portion is at least partially located closer to the head than the shoe holder in the inner portion. The two coupling portions are deformable in the widthwise direction when the swash plate applies load to the double-headed piston.

A swash plate type compressor includes a number of cylinders engaged in a receptacle, a number of pistons slidably engaged in the cylinders and movable relative to the cylinders in a reciprocating action, a spindle rotatably engaged in the receptacle, the receptacle includes a bore for partially receiving the spindle, a spring biasing member is engaged with the spindle, a holder is engaged onto the spindle, a swash plate is attached to the holder and coupled to the pistons for moving the pistons in the reciprocating action in the cylinders, and a control valve plate device is engaged with the cylinders for guiding the air to flow from the inlet chamber of the receptacle into the cylinders and from the cylinders into the discharge chamber of the receptacle.

An axial piston machine may include a a housing having vapor, cylinder chamber and wobble-plate chambers. The machine may have cylinders arranged annularly around a shaft in the cylinder chamber and having pistons arranged therein in a translationally movable manner, a valve disk connected to the shaft in a rotationally fixed manner and arranged in the vapor chamber, and a wobble plate connected to one of the pistons via a cup and ball bearing and to the shaft in a rotationally fixed manner, the wobble plate being arranged in the wobble-plate chamber. The housing may have steam-chamber, cylinder, and wobble-plate housing parts connected to one another. A cylinder sleeve having a radially protruding collar may be provided in at least one cylinder, wherein the cylinder sleeve may be retained via the collar in a cut-out in the cylinder housing part, which may adjoin a parting plane between the vapor-chamber and cylinder housing parts. The vapor chamber may be closed off by a first cover, which may be connected to the vapor-chamber housing part and which may be designed as a shaped sheet-metal part.

It is an object of the present invention to provide a semispherical shoe which can be prevented from being subjected to seizure even in a dry lubrication state in which there is no lubricating oil at the start time of an operation of a swash plate compressor, is excellent in its sliding contact property and load resistance, does not deteriorate in its lubricating property due to generated frictional heat, does not subject a resin layer to peeling from a base material, and ensures sufficient durability. It is another object of the present invention to provide a swash plate compressor in which a lubricating film is not formed on a sliding contact surface of the swash plate and that of a piston owing to the use of the semispherical shoe. A semispherical shoe (4) is subjected to sliding contact with the swash plate of the swash plate compressor and the piston thereof. Abase material (5) consists of a metallic member. A resin layer (6b) is formed on a surface of a planar part (4b) to be subjected to sliding contact with the swash plate. A resin layer (6a) is formed on a surface of a spherical part (4a) to be subjected to sliding contact with the piston. The resin layer (6a) and the resin layer (6b) are integral with each other. At least one portion of the base material (5) is not covered with the resin layer (6) and is exposed.

A miniature air pump includes a motor unit, a valve unit and a compression unit. The compression unit is driven by the motor unit to input or output airflows via the valve unit. The compression unit includes an air chamber module and a linkage rod. The air chamber module includes a plurality of compressible chambers and a plurality of resilient connection members, each resilient connection member is located on each compressible chamber. The linkage rod is connected with the motor unit and includes a central rod and multiple sleeves extending from the central rod. Each sleeve has a side cutout. Each resilient connection members engages each sleeve via the side cutout such that the motor unit drives the air chamber module to be compressed or decompressed to input or output airflows via the valve unit. A longitudinal direction of the side cutout is in parallel with the central rod.