218 results about "Variable displacement" patented technology

A hydraulic system includes a prime mover, a variable displacement first hydraulic pump to be driven by the prime mover to deliver hydraulic fluid, a first hydraulic actuator to be driven by fluid delivered by the first hydraulic pump, a variable displacement second hydraulic pump to be driven by the prime mover to deliver hydraulic fluid, a second hydraulic actuator to be driven by fluid delivered by the second hydraulic pump, and first and second restrictors configured or programmed to restrict an output of the respective first and second hydraulic pumps based on a load on the prime mover. The first restrictor is configured or programmed to change an output restriction of the first hydraulic pump based on priority information about the first and second hydraulic actuators and / or the second restrictor is configured or programmed to change an output restriction of the second hydraulic pump based on the priority information.

The invention relates to the technical field of injection molding machine hydraulic control, in particular to an injection molding machine hydraulic pump control system and a control method thereof, and aims to solve the problems of high energy consumption, high cost or poor temperature control of a traditional hydraulic scheme. The system comprises a hydraulic oil tank, a driving unit and an oil way control module. The driving unit comprises a driving motor, and a fixed displacement pump and a plurality of swash plate type variable displacement piston pumps which are driven by the driving motor, and swash plates of the variable displacement pumps can be switched between negative and positive angles so as to adjust the displacement or actively suck oil; the oil way control module is provided with a flow collecting valve set capable of switching flow collecting / independent states of oil outlet ways of the constant displacement pump and the variable displacement pump, the integrated cooling unit forms an independent cooling filtering loop, the temperature and pressure adjusting assembly is combined with a temperature sensor to control temperature and adjust pressure, and the pressure limiting protection valve set is connected with the constant displacement pump and the variable displacement pump. And the pressure limiting protection valve is matched with a pressure sensor to realize overpressure protection. According to the invention, cost and energy saving are both considered, precise temperature control and pressure protection are realized, and system stability and plastic part forming precision are improved.

The invention relates to the technical field of industrial automation, and discloses a multi-mode switching control method for a variable displacement piston pump driven by a servo motor, which comprises the following steps of: acquiring multi-dimensional operation state parameters and load power of a variable displacement piston pump system; performing dynamic mode decomposition on the load power signal, and executing preset state switching compensation mapping to complete mode switching on the basis of the extracted mode characteristics and the current state parameter under the condition of judging that the switching condition is satisfied; executing a corresponding control strategy in the new mode, and dynamically adjusting the pump displacement and the rotating speed of the servo motor through feedback control; and detecting the response and energy efficiency performance of the regulation and control system according to the performance index in the system operation process. By adopting a dynamic mode intelligent switching mechanism, the system can automatically match the optimal operation mode in different working environments, the energy utilization efficiency is greatly improved, and the effects of effectively reducing energy waste and reducing the total energy consumption of the system during stable load or low load operation are achieved.

The invention relates to the technical field of loader hydraulic control, in particular to a low-power-consumption hydraulic system of an electric loader, aiming at steering and normal work of the loader, a first power module and a second power module which are independently regulated and controlled are respectively arranged, and independent valve port control is adapted by utilizing the coordination effect of a flow scheduling module and a pressure matching module; a throttling link is completely eliminated, an inlet valve port and an outlet valve port are fully opened, the pressure loss of oil flowing through the valve ports is reduced to the minimum, and the energy consumption of a whole machine steering loop is greatly reduced; and meanwhile, independent and accurate control over oil inlet and oil return of the oil cylinder is achieved through speed regulation of variable rotating speed and variable displacement, real stepless speed regulation is achieved by avoiding limitation of the opening degree of a main valve port, and therefore the energy efficiency of the system is greatly improved.

Apparatus and associated methods relate to using a Pulse-Width Modulated (PWM) electro-hydraulic solenoid valve to provide regulation of fluid displacement pumped by a variable-displacement hydraulic pump. The PWM electro-hydraulic solenoid valve regulates fluid conductivity between a hydraulic output port and a hydraulic control port of the variable-displacement hydraulic pump. Such regulation of fluid conductivity therebetween controls fluid displacement through the variable-displacement hydraulic pump. An electronic control unit is configured to generate and transmit a PWM electrical control signal to the PWM electro-hydraulic solenoid valve in response to a metric of the variable-displacement hydraulic pump as measured by a transducer. The electronic control unit generates the PWM electrical control signal so as to control the metric measured to within a predetermined control band about a target value.

A system includes a variable displacement pump (VDP) in fluid communication with an inlet line and with an outlet line. The VDP includes a variable displacement mechanism configured to vary pressure to the outlet line. A bypass valve (BPV) includes a BPV inlet in fluid communication with the outlet line, and a BPV outlet in fluid communication with a bypass line that feeds into the inlet line upstream of the VDP. A minimum pressure shutoff valve (MPSOV) is connected in fluid communication with the outlet line, configured to block flow through the outlet line for shutoff. The MPSOV is connected in fluid communication with the BPV for triggering recirculation through the BPV.

Apparatus and associated methods relate to using an electro-hydraulic solenoid valve to provide regulation of fluid displacement of a variable-displacement hydraulic pump. A mechanical control mechanism is configured to control displacement of hydraulic fluid pumped from a hydraulic input port to a hydraulic output port. The electro-hydraulic solenoid valve regulates fluid conductivity between a hydraulic output port of the variable-displacement hydraulic pump and a hydraulic control cylinder, which operates a hydraulic control piston coupled to the mechanical control mechanism controlling fluid displacement. An electronic control unit is configured to generate and transmit an electrical control signal to the electro-hydraulic solenoid valve in response to a metric of the variable-displacement hydraulic pump as measured by a transducer. The electronic control unit generates the electrical control signal so as to control the metric measured to within a predetermined control band about a target value.

The present application relates to the field of heating and ventilation technology, and particularly relates to a control method of a heating system. The present application aims to solve the problems of high cost and high risk of refrigerant leakage existing in the current heat pump heating. For this purpose, the heating system of the present application comprises a heat pump cycle and a water cycle, the heat pump cycle comprises a variable displacement compressor, a tubular heat exchanger, a throttling device and an evaporator connected through a refrigerant pipeline, the water cycle comprises an indoor radiator and the tubular heat exchanger connected through a heat exchange pipeline, the refrigerant in the heat pump cycle and the circulating water in the water cycle exchange heat in the tubular heat exchanger, the variable displacement compressor has two compression cylinders, and the control method comprises: acquiring an outdoor environment temperature; determining a working mode of the variable displacement compressor according to a temperature interval in which the outdoor environment temperature is located; and controlling the variable displacement compressor to operate based on the working mode. The present application has good heating effect, low cost, low risk of leakage and good heat pump heating effect.

The invention discloses a variable-displacement water pump for an engine and a water pump displacement control method, and relates to the technical field of water pumps, the variable-displacement water pump comprises a pump body, an impeller disc, an elastic part and a driving part, a pump shaft is rotationally connected to the center of the pump body, an impeller cover is fixedly connected to one end of the pump shaft, and a plurality of blades are arranged on the face, facing the pump body, of the impeller cover in the circumferential direction; the impeller disc sleeves the pump shaft, the impeller disc and the impeller cover are coaxially and oppositely arranged, the impeller disc can slide in the axial direction of the pump shaft, the impeller disc is provided with holes allowing the blades to penetrate through, the hole walls of the holes and the peripheral surfaces of the blades define liquid drainage intervals, the pump shaft is sleeved with the elastic piece, one end of the elastic piece abuts against the impeller disc, and the other end of the elastic piece abuts against the impeller disc. The driving part is arranged on the face, away from the impeller cover, of the impeller disc, the driving end of the driving part abuts against the impeller disc, and the acting force of the elastic part is opposite to that of the driving part. The size of the liquid drainage interval is adjusted through cooperation of the driving piece and the elastic piece, and variable displacement and oil consumption reduction are achieved.

The application discloses a device of a circular ring type plunger variable hydraulic pump, which comprises a base, a curved rod, a piston, a swing rod two, a rear cover, a connecting rod five, a connecting rod six, a compression bolt, a connecting rod eight and a main shaft two. The base is fixedly connected with the rear cover through welding. The outer side of the rear cover is in butt joint with a sealing gasket and a front cover, and the sealing gasket, the front cover and the rear cover are fixed through bolts. The device of the circular ring type plunger variable hydraulic pump can reduce the volume of the whole device in the axial direction while pumping oil. Only a given signal is needed to operate the driving circuit of the stepping motor, so that the stepping motor rotates at a corresponding speed and rotates a corresponding number of turns. The gear installed on the stepping motor drives the rack to move a corresponding distance, so that three groups of hinges move, the distance of the linear motion of the other end of the connecting rod two is changed, the included angle of the connecting rod one and the connecting rod three is changed, the swing angle of the swing rod one and the swing rod two is changed, and then the movement distance of the piston is changed, so that the variable oil pumping is realized.

An oil pump capable of optimizing the noise problem of first starting after long-term standing relates to the technical field of variable displacement vane pumps, and comprises a pump body, a sliding block is arranged in an oil cavity of the pump body, a vane cavity is arranged in the sliding block, a vane is arranged in the vane cavity, an oil storage cavity capable of storing oil during shutdown is arranged in the pump body, and the vane is arranged in the oil storage cavity. A pressure discharging hole used for discharging excessive oil is formed in the upper portion of the oil storage cavity, the lowest point of the oil storage cavity is located at the lowest point of the pump body oil cavity, and the oil in the oil storage cavity can enter the sliding block from the end face gap of the sliding block so as to be used for rapidly providing oil for the blade cavity during starting. According to the utility model, the technical effects that the oil pressure is fast and stable, the blades are fast lubricated and the air mixing amount is relatively low after long-term standing during first-time starting can be realized, and the blade knocking abnormal sound is weakened to a great extent.

A valvetrain control system includes a rocker shaft that attaches to an engine assembly and includes an internal bore that receives hydraulic fluid. An oil control valve (OCV) is attached to the rocker shaft and fluidly coupled to the internal bore to receive therefrom hydraulic fluid. Pivotably mounted onto the rocker shaft is a rocker arm with opposing ends thereof that mate with a pushrod and a valve. The rocker arm includes a spring lock unit that attaches to the pushrod and fluidly couples to the OCV to receive hydraulic fluid and thereby drivingly disengage the rocker arm from the pushrod. An insert sleeve mounted in the internal bore receives hydraulic fluid from the rocker shaft. The insert sleeve includes a feed port that transmits hydraulic fluid from the insert sleeve to the OCV, and a feed pocket that transmits hydraulic fluid from the OCV to the spring lock unit.

The application relates to the technical field of air conditioners, and discloses a control method for a variable displacement compressor air conditioner, wherein an exhaust port of a variable displacement compressor is connected to a variable displacement chamber of the variable displacement compressor through an exhaust pipeline, and an electric heating device is arranged on the exhaust pipeline; the control method comprises the following steps: in the case that the variable displacement compressor air conditioner executes a heating mode, obtaining an exhaust temperature of the variable displacement compressor, an exhaust pressure and a saturated steam temperature corresponding to the exhaust pressure; and in the case that the difference between the exhaust temperature and the saturated steam temperature is less than a first temperature, controlling the electric heating device to start. The method can avoid liquid accumulation in the variable displacement chamber and eliminate noise caused by liquid accumulation. The application further discloses a control device for the variable displacement compressor air conditioner, a variable displacement compressor air conditioner and a storage medium.

The application discloses a hydraulic driving multi-cylinder double-acting variable piston diaphragm pump. The pump comprises a pump base body, a power end, a liquid cylinder body, a diaphragm tank and a buffer tank which are installed on the pump base body, the power end is connected with the liquid cylinder body, the diaphragm tank is connected with the liquid cylinder body through connecting pipes respectively, flanges at two ends of the diaphragm tank are connected with suction valves and discharge valves respectively, wherein, the lower end suction valves are connected with suction pipes respectively, the upper end discharge valves are connected with discharge pipes respectively, and the discharge pipes are connected with the buffer tank. The application adopts a swash plate mechanism to realize the reciprocating motion of the multi-cylinder piston, drives the fluid medium in the working cavities on both sides of the piston to make the diaphragm in the diaphragm tank periodically concave-convex deformation, and realizes the self-suction of the pump feeding pulp from the suction pipe and the output of the discharge buffer tank. The diaphragm pump has the advantages of compact structure, small size, reduced output flow pulsation and reduced pulsation load impact of the filter press feeding on the filter plate.

The present application relates to the air conditioning technical field, specifically to a kind of air conditioner's shunt control method.This application aims to solve the problems of existing shunt mode, such as complex shunt system, large structure space, not conducive to assembly and application.To this end, the air conditioner of the present application is provided with a variable displacement compressor, the indoor heat exchanger includes inner discharge heat pipe line, outer discharge heat pipe line and the communication pipe line connecting the two, the outdoor heat exchanger includes a plurality of heat pipe sections and the on-off valve group that can switch the communication form between heat pipe sections, and the control method includes: obtaining the operating mode of the air conditioner;Based on the operating mode, determine the communication form of the outdoor heat exchanger and the indoor heat exchanger, and the working mode of the variable displacement compressor;Based on the communication form and the working mode, control the air conditioner to work.This application can realize the adaptive coupling change of shunt, improve the heat exchange effect of air conditioner, and the variable displacement compressor can further improve the operating efficiency of air conditioner.

A valve train control system comprises a rocker arm shaft mounted to an engine assembly and featuring an internal bore that receives hydraulic fluid. An oil control valve (OCV) is mounted on the rocker arm shaft and is fluid-connected to the internal bore to receive hydraulic fluid. A rocker arm is pivotally mounted on the rocker arm shaft, its opposite ends mating with a pushrod and a valve. The rocker arm includes a spring-loaded locking assembly attached to the pushrod and fluid-connected to the OCV to receive hydraulic fluid and thereby release the rocker arm from the pushrod. An insert sleeve mounted in the internal bore receives hydraulic fluid from the rocker arm shaft. The insert sleeve includes a feed port that transfers hydraulic fluid from the insert sleeve to the OCV and a feed pocket that transfers hydraulic fluid from the OCV to the spring-loaded locking assembly.

The present disclosure relates to a positive displacement machine device (1) comprising a constant displacement machine (2) with a fixed displacement volume and a variable displacement machine (3) with an adjustable displacement volume, wherein in pump operation of the positive displacement machine device (1) a fluid (4) can be conveyed from an inlet (5) of the positive displacement machine device (1) to an outlet (6) of the positive displacement machine device (1) by means of the constant displacement machine (2) and / or the variable displacement machine (3), wherein in motor operation of the positive displacement machine device the constant displacement machine and / or the variable displacement machine can be driven by fluid flowing from the inlet to the outlet. Noise emissions of the displacement machine device (1) are reduced and / or the displacement machine device (1) can be operated at high speed by fluidically connecting the inlet (5) to a first port (21) of the constant displacement machine (2) and to a first port (31) of the variable displacement machine (3), and wherein the outlet (6) is fluidically connected to a second port (22) of the constant displacement machine (2) and to a second port (32) of the variable displacement machine (3).

The utility model discloses a variable displacement compressor top clearance measuring device which comprises a device frame, a pressing assembly, a positioning tool, a detection tool and a jacking assembly are arranged in the device frame, the pressing assembly is located over the positioning tool, the pressing assembly is provided with an automatic lifting pressing plate, the pressing assembly further comprises a lifting air cylinder, and the lifting air cylinder is connected with the detection tool. The telescopic end of the lifting air cylinder is fixedly connected with a rotating motor, the rotating motor is connected with a rotating head through a speed reducer, the rotating head movably penetrates through the pressing plate and then is fixedly connected with a compressor main shaft in an inserted mode in the radial direction, the jacking assembly comprises a jacking air cylinder, the telescopic end of the jacking air cylinder is connected with a detection tool, and a displacement sensor is installed on the side face of the detection tool. The lower end of a piston rod of the top piston cylinder is connected with a displacement sensor contact plate. The device is high in automation degree in the whole process, and improves the measurement efficiency and precision.

A variable-capacity turbocharger has: a turbine housing that accommodates a turbine impeller; a variable nozzle assembly with a nozzle vane arranged in a nozzle flow channel provided around the turbine impeller in the turbine housing, and a drive mechanism designed to drive the nozzle vane; a disc spring designed to bias the variable nozzle assembly in an axial direction so that it is pressed against a section of the turbine housing; a pin extending from the bearing housing; and a U-groove provided on the variable nozzle assembly that allows the insertion of a distal end of the pin.The U-groove has a pair of inner wall surfaces designed as parallel flat planes intersecting in the circumferential direction, and which hold the distal end of the pin between them in the circumferential direction, with the distal end of the pin being press-fitted between the inner wall surfaces.

The invention provides a variable displacement internal gear pump and a displacement adjusting method thereof, and relates to the technical field of pump equipment, the variable displacement internal gear pump comprises an upper end cover, a bearing shaft, a bearing, an upper shell, a gear shaft, a lower shell and a variable structure; the variable structure comprises a gear-shaped gasket, an outer gear ring, an auxiliary plate and a plurality of variable adjusting assemblies. Each variable adjusting assembly comprises a first variable adjusting rod, a second variable adjusting rod, a spring and a third variable adjusting rod. The outer gear ring and the gear-shaped gasket are completely meshed, a plurality of flow holes are evenly formed in the outer gear ring, and the outer gear ring can move outside the gear-shaped gasket under the action of the variable adjusting assembly, so that the meshing width of the outer gear ring and the gear-shaped gasket can be adjusted. By means of the internal meshing variable gear pump, stepless adjustment of the displacement can be achieved, and the internal meshing variable gear pump has the advantages of being low in flow pulsation, good in self-suction capacity, quiet in operation, low in cost and the like when applied to a volume speed adjusting system.

This invention discloses a method for designing the additional angle of the swashplate in a constant pressure variable displacement piston pump, comprising the following steps: A. When the additional angle β is 0, based on the inlet pressure P of the variable displacement pump... 始 Constant pressure P 终 Given the maximum swashplate angle α, determine the compression angle B. Based on equations 1 and 2), calculate the corresponding additional angle β at the maximum swashplate angle α. Then, using equation 3), calculate the angle C between the z-axis and the low-pressure zone oil window of the distributor plate. Calculate the curves showing the volume ratio changing with the additional angle β at different swashplate angles α. The intersection of these curves represents the optimal design value for the additional angle β under different operating conditions. This invention enables the variable pump to minimize pressure pulsation under any operating condition, thereby improving the performance of the constant pressure variable piston pump and the reliability and lifespan of the onboard hydraulic system.

A variable displacement hydraulic pump including a control actuator configured to interact with a movable displacement control member to control the displacement of the pump; and a displacement control valve assembly configured to provide mechanical feedback control of positioning of the control actuator and thereby the displacement control member. The displacement control valve assembly includes a control valve member that is movable within a fluid flow path of the control valve assembly to control a flow of fluid to or from the control actuator. The control valve assembly includes a first valve part, a second valve part, and a biasing member configured to selectively position respective one or more portions of the first and second valve parts relative to each other to open or close a vent flow passage in response to an operating state of the pump. When in a normal operating state of the pump, the biasing member is configured to position the first and second valve parts relative to each other such that the vent flow passage is closed, and the control valve member moves in the fluid flow path to control the flow of fluid to or from the control actuator. When in a failsafe state of the pump, the biasing member is configured to position the first and second valve parts relative to each other such that the vent flow passage is opened, thereby enabling fluid from the control actuator to escape via the vent flow passage.

A variable displacement oil pump according to the present invention has a protrusion (46) that is partially formed on a spring contact surface (451) of an arm part (45) of a cam ring (4) so as to overlap with part of the outer circumference of a coil spring (SP). This protrusion (46) restricts tilting of the coil spring (SP) and makes it possible to suppress positional deviation of the coil spring (SP). Furthermore, because the protrusion (46) is provided partially on the spring contact surface (451) of the arm part (45) of the cam ring 4, the coil spring (SP) need only be pushed inward of the protrusion (46) when installing the coil spring (SP), thus making it possible to ensure ease of installation of the coil spring (SP).

This invention discloses an articulated / tracked dual-mode steering system, comprising a front articulated chassis and a rear articulated chassis. A front axle is connected to the lower part of the front articulated chassis, and a rear axle is connected to the lower part of the rear articulated chassis. Both ends of the front and rear axles are connected to a triangular track via hydraulic motors. A steering gear is mounted on the front articulated chassis, with its lower end connected to a hydraulic steering unit. The two outlets of the hydraulic steering unit are connected to a left and a right steering cylinder, respectively. The system also includes two variable displacement hydraulic pumps connected in series. One variable displacement hydraulic pump is connected to two hydraulic motors located on the right side, and the other variable displacement hydraulic pump is connected to two hydraulic motors located on the left side. This invention also discloses a vehicle. This invention combines two steering modes into a single working vehicle, allowing the vehicle to use either articulated steering or tracked steering depending on the actual situation, fully utilizing the advantages of both steering modes.

The invention provides a variable displacement vane pump which can adjust the full cut-off pressure in a wide range from low pressure to high pressure by using a single pump without changing a spring. A vane pump is provided with: a plurality of vanes slidably protruding from a rotor that is rotatable about a shaft; a cam ring having an inner peripheral surface in sliding contact with the outer peripheral end of the blade, and being eccentrically rotatable with respect to the shaft; a high-pressure-side spring that urges the cam ring via the plunger; a low-pressure-side spring which is at least partially housed in the holder and which biases the cam ring via the holder and the plunger; a stopper provided on an end side of the low-pressure-side spring opposite to the plunger side; and a pressure adjusting part capable of adjusting the position of the stopper from a position where the stopper does not abut against the stopper even if the cam ring moves the holder to a position where the stopper always contacts the holder or more.

The utility model discloses a variable displacement oil pump, which comprises a pump body, an oil pump, a first oil pump, a second oil pump and a second oil pump, wherein an accommodating space and a feedback oil duct are arranged in the pump body; the aligning ring is arranged in the accommodating space, a control oil cavity is formed between the outer wall surface of the aligning ring and the inner wall surface of the accommodating space, the control oil cavity is communicated with the feedback oil duct, and the aligning ring can move along a preset path; the rotor is located in the aligning ring, the rotor and the aligning ring are eccentrically arranged, and the rotor can rotate with the preset axis as the center; the partition pieces are arranged in the aligning ring and used for dividing the space between the outer wall face of the rotor and the inner wall face of the aligning ring into a plurality of closed areas, and the areas of the different closed areas are different; and at least part of the pressure regulating valve is located in the feedback oil duct. Compared with the prior art, through the arrangement of the aligning ring and the pressure regulating valve, the requirement of the engine on the engine oil pressure under different working conditions can be automatically regulated, the engine oil pressure is always in a relatively ideal area, the power loss of the engine is reduced, and the fuel economy of the engine is improved.

The nozzle member of at least one embodiment of the present disclosure is a nozzle member included in a variable nozzle mechanism of a variable capacity turbocharger. The nozzle member is composed of an iron-based alloy. In a case where a total value of a carbon content and a nitrogen content of the nozzle member is set as A mass%, and a total value of 0.5 times a tungsten content and a molybdenum content is set as B mass%, a relationship indicated by the following expression is satisfied: 6.6 x A + B ≥ 8.0. A value of the total value B is 1.5 mass% or more.

The invention discloses a distributed hydraulic driving system for a guniting robot, and belongs to the technical field of engineering machinery, and the distributed hydraulic driving system comprises an engine for providing power; the input end of the transfer case is connected with an output shaft of the engine; the input ends of the four variable pumps are respectively connected with the four output ends of the transfer case; each variable displacement motor and a variable displacement pump form an independent hydrostatic transmission loop through a hydraulic oil way, an output shaft of each variable displacement motor is connected with a hub reduction gear, and the output ends of the hub reduction gears drive four crawler walking devices of the guniting robot respectively. The maneuverability and reliability of the robot in narrow and fluctuating roadways can be enhanced, and the adaptability to complex terrains and the operation continuity are remarkably improved.

The embodiment of the application discloses a low-temperature control method of a variable displacement engine oil pump system, a vehicle and electronic equipment. The low-temperature control method of the variable displacement engine oil pump system comprises the following steps: after the engine is started, if the ambient temperature detected by an ECU control module is less than a first preset temperature, a low-temperature control strategy is executed; the low-temperature control strategy comprises the following steps: if the ambient temperature is less than the first preset temperature and the oil temperature of the engine is less than or equal to a second preset temperature, the oil pressure of the variable displacement engine oil pump is controlled to work at a preset pressure until the oil temperature of the engine is greater than the second preset temperature; if the ambient temperature is less than the first preset temperature and the oil temperature of the engine is in a preset temperature interval, the oil pressure of the variable displacement engine oil pump is controlled to work at the preset pressure and a preset time. The application greatly improves the engine low-temperature oil pressure establishment time, accelerates the engine oil temperature rising speed, and reduces the wear of the piston ring and other moving parts.

The utility model discloses a variable capacity piston device, even in the case where the supporting ball uses steel material, can fully ensure the wear resistance, load resistance, can realize the low cost. The structure of the utility model discloses a variable capacity piston device is characterized in that, have: cylinder barrel (110), it is supported in the casing (102) in the mode that can rotate with the shaft (104) together, a plurality of pistons (112) are inserted in the cylinder barrel (110) in the mode that can slide along the axial direction, the inclined plate (120) makes the stroke change of piston (112), and two supporting balls (130) support the inclined plate (120) as can rotate, and the supporting ball (130) uses the steel material of tempering temperature 500 DEG C or more, and the surface is implemented with soft nitriding treatment.