Hydraulic rotary machine and method for manufacturing hydraulic rotary machine

Abstract

The invention provides a hydraulic rotating machine capable of improving the wearing performance and the lubricity of the sliding surface of the cylinder and the piston and a manufacturing method thereof. The hydraulic rotating machine(1) comprises a housing (2), a rotating shaft (3), a cylinder body (4), a piston (5), a slipper shoe (6), an inclined plate (7), and a valve plate (8). A cylinder hole (15) passes through the cylinder body (4), and a nitrogen diffusion layer (30) and a nitrogen compound layer (31), which are disposed in the cylinder hole (15) in the cylinder body (4), and are respectively the surface side of the sliding surface of the piston (5). The nitrogen diffusion layer (30) is disposed on a parent metal (34) side made of iron materials of the cylinder body (4), and the nitrogen compound layer (31) is disposed on the nitrogen diffusion layer (30). The parts of the surface sides of the nitrogen compound layer (31) and the nitrogen diffusion layer (30) can be removed to form the nitrogen diffusion layer (30), which can be exposed by removing the nitrogen compound layer (31), and the concave nitrogen compound layer (32), which is provided with the nitrogen compound layer in the concave part, can be provided.

Description

technical field [0001] The present invention relates to hydraulic rotary machines such as hydraulic pumps and hydraulic motors, and methods of manufacturing the same, and more particularly, to a hydraulic rotary machine relating to a cylinder bore (cylinder bore, cylinder bore) and a sliding portion of a piston in a cylinder constituting a hydraulic rotary machine. Hydraulic rotating machines and methods of manufacture thereof. Background technique [0002] Hydraulically driven machines represented by hydraulic pumps and hydraulic motors are composed of many sliding parts. Their sliding surfaces have problems such as sintering between sliding surfaces and partial abnormal wear due to the influence of breakage of the lubricating oil film due to high sliding surface pressure and instability of the sliding contact state due to fluctuations in control hydraulic pressure. risks of. Therefore, almost all sliding members constituting the sliding portion are made of steel material...

AI Technical Summary

Problems solved by technology

[0010] However, in Patent Document 1, there is a problem that since the sliding surface of the cylinder bore is a smooth surface, the lubricating oil film is cut off between the cylinder bore and the piston at the high surface pressure contact point with the piston. Therefore, Wear and seizing phenomena based on solid contact between cylinder bore and piston

[0011] In addition, in Patent Document 2, there is a problem that since the copper alloy composition used for sintering the copper alloy and the cooling temperature control in the sintering process need to be strictly controlled, the manufacturing process becomes complicated, and the copper alloy material The price is high, so it will lead to a substantial increase in cost

[0012] In addition, in Patent Document 3, there is a problem that in order to process a concave shape with respect to a shape such as a cylinder bore of a cylinder block, the positioning of the workpiece and the machining trajectory of the machining tool become complicated, and therefore an expensive multi-axis Processing equipment, and the processing time will be longer

In addition, when the concave shape is worn due to sliding, similar to the case of a smooth ground surface, burning due to oil film fracture occurs.

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