187 results about "Light metal" patented technology

The invention relates to the technical field of grabbing manipulators, and discloses a self-adaptive grabbing device for a special-shaped curved surface workpiece, which comprises a central bearing base made of a light metal material and provided with a multifunctional quick connector at the top; the central adsorption module is fixed at the central position of the bottom of the central bearing base and comprises an air pressure balance pipeline communicated with an external air source; by means of radial adjustment of the cross shaft and cooperation of the elastic buffering structure and the vertical guiding assembly, high-precision centering and stable adsorption are achieved, vertical contact of the suction cup is ensured through vertical guiding, the suction cup is suitable for different curved surface radians, and the stable adsorption force under the small area is kept; and electric control connection supports installation, namely electrification, and is suitable for automatic precise grabbing.

To overcome current countermeasures against a bear that involve making human presence known through group movements, conversation, and sounds such as bells and radios, thereby giving early warning to the bear so as to expect its voluntary leaving, where, if the bear decides to attack contrary to the expectation, however, there is nothing that can be done, so these are uncertain and incomplete countermeasures.SOLUTION: A bear repelling stick is characterized in that forming processing is performed with hard and higher-strength materials such as iron or light metal on a stick as a standard item for mountain walking in order to add defense power and offense power for fighting back against the attack of a bear in addition to a walking assisting function so that the stick is not broken even if it receives the attack of the bear, and a function to exert hitting capability to beat the bear to death when swung down is provided.SELECTED DRAWING: Figure 1

The invention relates to the technical field of material surface treatment, and discloses a preparation method of a microcapsule-based self-repairing coating, the self-repairing coating and a light metal alloy. The preparation method of the self-repairing coating comprises the following steps: adding microcapsules into a mixed solution of epoxy resin and a curing agent, and stirring to obtain a coating; the surface of a base body is coated with the paint, and a self-repairing coating is obtained; the preparation method of the microcapsule comprises the following steps: preparing a prepolymer solution which comprises the following components: urea and formaldehyde; preparing an oil-in-water emulsion, namely adding tung oil into a surfactant solution, and emulsifying to obtain the oil-in-water emulsion; and mixing the prepolymer solution and the oil-in-water emulsion to obtain the microcapsule. When the self-repairing coating is damaged, the microcapsules at the damaged part are broken, the core material tung oil is released, the core material flows in the coating and fills the damaged part, and the damaged part is repaired, so that the automatic repairing effect is achieved, the corrosion speed of an alloy matrix is slowed down, and the corrosion resistance is improved.

The invention discloses a method for enriching light metal ions in a pore channel based on carbon nanofiber / carbon fiber nano confinement, and belongs to the technical field of sample pretreatment, and the method comprises the following steps: S1, preparing a carbon nanofiber / carbon fiber confinement material; and S2, putting the carbon nanofiber / carbon fiber confinement material obtained in S1 into a light metal ion solution, and stirring. According to the method for enriching the light metal ions in the pore channel based on the carbon nanofiber / carbon fiber nano confinement, the carbon nanofiber / carbon fiber is used as a confinement fluid carrier, ultrapure water, methanol or n-hexane is used as an extracting agent, a chelating agent does not need to be introduced, the method is green and environmentally friendly, the mass transfer rate is increased, and the method is suitable for large-scale industrial production. Therefore, high enrichment of light metal ions in water is realized.

A casting mould for producing a casting formed from a light metal alloy, in particular a housing for an electric drive for a motor vehicle. The casting mould advantageously has at least one sand core which is designed and arranged in the casting mould in such a way that the at least at least one sand core can be completely surrounded, at least in sections, in a circumferential direction by a light metal melt with which the casting mould is filled to form the casting. It is advantageous to be able to produce a casting in which, for example, a cooling channel is incorporated. It is not necessary to drill a hole to form a channel. Furthermore, the invention relates to a process for manufacturing a casting made of a light metal alloy, in particular a housing for an electric drive for a motor vehicle.

The invention discloses a preparation method of an amorphous high-entropy alloy multilayer film, which comprises the following steps of: S1, coating a film on a substrate by adopting a TiVZrNb alloy target material through a magnetron sputtering method to form a TiVZrNb alloy film layer; s2, adopting a transition metal target material or a light metal target material to continuously coat the TiVZrNb alloy film layer through a magnetron sputtering method to form an interlayer metal film layer; s3, continuously coating a film on the interlayer metal film layer by adopting a TiVZrNb alloy target material through a magnetron sputtering method to form a TiVZrNb alloy film layer; s4, circularly repeating the step S2 and the step S3; and S5, after the step S4 is completed, the amorphous high-entropy alloy multilayer film is prepared. According to the preparation method, non-crystallization of the refractory high-entropy alloy is achieved through the magnetron sputtering technology, the TiVZrNb alloy multilayer film containing the transition metal interlayer or the light metal interlayer is prepared and has excellent hydrogen storage performance and good structural stability, and effective application of the refractory high-entropy alloy in the field of hydrogen storage materials is achieved.

The present application provides a solid-state hydrogen storage material and a preparation method and application thereof. Specifically, the preparation method comprises the following steps: (1) ball-milling a magnesium-based alloy powder, a light metal hydride, a nano-carbon material, a composite catalyst powder and an interface modifier to obtain a mixed powder; and (2) sintering the mixed powder under vacuum at 200-350 DEG C for 2-5 hours to obtain a sintered body, wherein: the magnesium-based alloy powder is a Mg-Mn-Al alloy powder; the light metal hydride is a mixture of LiAlH4 and NaBH4; the nano-carbon material is selected from one or more of graphene and carbon nanotubes; the composite catalyst powder is a mixture of TiO2, Fe3O4, CeO2 and La2O3; and the interface modifier is selected from one or more of a silane coupling agent and a titanate coupling agent. The solid-state hydrogen storage material has high hydrogen storage capacity, fast hydrogen absorption and desorption rate and good cycle stability.

The invention belongs to the technical field of light metal smelting and nano materials, and particularly discloses a nano aluminum powder electrolysis preparation method based on ionic liquid. The method comprises the following steps: mixing an ionic liquid, an additive and AlCl3 to obtain an electrolyte, and carrying out an electrolytic reaction by taking aluminum as a cathode and an inert electrode as an anode to prepare nano aluminum powder; the additive is specifically halide salt. The halide salt is added as an additive and can partially replace ionic liquid, so that the preparation cost of the nano aluminum powder is reduced; in addition, the halide salt can also avoid the phenomenon that the aluminum powder is adhered to the cathode, so that the particle size of the obtained nano aluminum powder becomes smaller and is more uniform, the nano aluminum powder with narrower particle size distribution is obtained, and the related performance during application is improved. The preparation method disclosed by the invention also has the advantages of low electrolysis temperature and low energy consumption, and the reaction can be protected by adopting a protective atmosphere in the electrolysis process, so that the preparation safety of the aluminum powder is greatly improved.

The invention aims to provide a device and process for preparing a fine-grain magnesium alloy plate through turning arc-shaped roller rolling, and belongs to the technical field of light metal plastic forming, and the device comprises a special-shaped roller, a flat roller and a motor; the special-shaped rollers comprise the upper special-shaped roller and the lower special-shaped roller, the lower special-shaped roller is horizontally arranged, and the included angle between the axis of the upper special-shaped roller and the axis of the lower special-shaped roller is 20-45 degrees. The two ends of the upper special-shaped roller and the two ends of the lower special-shaped roller are connected with an upper bevel gear and a lower bevel gear through roller shafts respectively, the upper bevel gear and the lower bevel gear located at the same end are meshed with each other, and the lower bevel gear located at one end is connected with a motor through a coupler. The flat roller is located behind the discharging end of the special-shaped roller, the included angle between the axis of the flat roller and the axis of the lower special-shaped roller which is horizontally placed is 0-45 degrees, and the fine-grain magnesium alloy plate with the weak basal texture is finally manufactured through the method. The problem that a traditional magnesium alloy plate is prone to forming a strong basal texture is solved, and the performance of the magnesium alloy plate is effectively improved.

A lower dash for a motor vehicle that extends in a y-direction transversely to the direction of travel for the motor vehicle and separates a passenger compartment and a front compartment of the motor vehicle. The lower dash includes a partial bulkhead, an inner partial A-pillar arranged laterally with respect to the patrial bulkhead, and a side member front including a connector, each on the left and right sides in the vehicle direction. The inner partial A-pillar, the partial bulkhead, and the side member front arranged on the left side are designed as a one-piece part-lower dash made of die-cast light metal, and the inner partial A-pillar, the partial bulkhead, and side member front on the right side are designed as a one-piece part-lower dash made of die-cast light metal. The one-piece part-lower dash arranged on the left-hand and right-hand sides are connected to one another via a joining.

The invention aims to provide a device and a method for preparing a fine-grain magnesium alloy pipe, and belongs to the technical field of light metal plastic forming. Differential torsion and continuous shear deformation are generated in the machining process of a magnesium alloy pipe blank, grain refinement and texture weakening are achieved while the torsion direction of the blank is not changed, and the yield of the fine-grain magnesium alloy pipe is improved. Room-temperature mechanical properties of magnesium alloy pipes are improved, and the magnesium alloy application range is widened. By means of the method, the grain refining effect of the magnesium alloy pipe is more remarkable, the basal texture is weakened to a large extent, the obtained fine-grain magnesium alloy pipe is uniform in structure, and the obdurability is greatly improved.

A battery carrier for receiving at least one battery module serving as a drive energy storage device for an electrically driven vehicle. The battery carrier can be connected to a body of the vehicle, including a substantially circumferential frame structure having longitudinal sides and transverse sides for forming a receiving area for the at least one battery module, wherein the battery carrier is integrally molded from a light metal material, in particular integrally cast from a light metal material. The receiving area encloses an area of at least 0.5 m2, in particular of at least 0.75 m2, particularly preferably of at least 1 m2. The present invention also relates to methods for die casting a substantially one-piece battery carrier from a light metal melt, in particular from an aluminum alloy melt.

The invention discloses a pressurizing injection semi-solid magnesium alloy injection device, and relates to the technical field of injection devices, the pressurizing injection semi-solid magnesium alloy injection device comprises an injection mechanism, a pressurizing mechanism and a mold closing mechanism, the injection mechanism melts light metal alloy slurry, and the injection mechanism is communicated with a charging barrel of the pressurizing mechanism through a channel; molten light metal alloy slurry is injected into the charging barrel through the channel, the pressurizing mechanism further comprises an injection rod, the injection rod can be axially and movably arranged in the charging barrel, the injection rod injects the molten light metal alloy slurry into the mold closing mechanism to form a workpiece, a flange is arranged at the tail end of the injection mechanism, and the injection mechanism is connected with the injection mechanism. The flange is fixedly connected with the charging barrel, an injection rod is arranged on one side of the pressurizing mechanism, a punch is arranged at one end of the injection rod, and the punch is nested in the charging barrel in a sliding mode. The method has the beneficial effects that the die-casting speed is high, the filling pressurization is large, and the technical advantages of semi-solid injection molding pulping are achieved.

The invention discloses a polarization-adjustable antiferromagnetic terahertz source based on a MnPt heterojunction. The polarization-adjustable antiferromagnetic terahertz source comprises a MnPt antiferromagnetic thin film layer, a light metal layer and an anti-oxidation layer, according to the invention, the femtosecond laser is used for exciting the femtosecond laser to generate the terahertz wave, the polarization direction of the generated terahertz wave is changed along with the change of the polarization direction of the femtosecond laser, that is, the polarization direction of the laser is changed by 1 degree, the polarization direction of the terahertz is changed by 2 degrees, the change of the azimuth angle of a sample is not needed, and the width of the generated terahertz spectrum exceeds 5 THz. No extra heavy metal layer needs to be added, the size is miniature, and the thickness is smaller than 40 nm. By adjusting polarization and phase difference of femtosecond laser, adjustability of a linear polarization state, an elliptical polarization state or a circular polarization state can be achieved, the structure is simple, a needed light path is simple, assistance of an external magnetic field or current is not needed, micromachining is not needed, the ultra-high external magnetic field interference resistance is achieved, the cost is reduced, and the application range is wide. And integration of the terahertz source is also facilitated.

The invention discloses a block magnesium-based composite material capable of quantitatively regulating and controlling the content of nano-particles and a manufacturing method of the block magnesium-based composite material, and belongs to the technical field of metal-based composite material preparation. The method comprises the following steps: providing a magnesium alloy substrate and a cover plate, determining the sectional dimension of a groove of the cover plate according to the volume fraction of target nanoparticles, processing the groove, then filling the groove with the nanoparticles, assembling the cover plate on the substrate in an inverted buckling manner to form a to-be-processed assembly, performing multi-pass stirring friction processing to form a first composite material layer, and stacking the first composite material layer as a new substrate layer by layer to form a second composite material layer; and finally, the target block magnesium-based composite material is prepared. Through the correlation design of the groove size and the target volume fraction, accurate control and uniform dispersion of the nano-particle content are achieved, the problems that a traditional method is high in defect rate, limited in size and the like are solved, the strength and plasticity of the prepared material are remarkably improved, the process is green and environmentally friendly, and the method is suitable for mass production of large-size components and can be popularized to various light metal matrixes; the application prospect is wide.

The invention relates to the technical field of graphite purification, and discloses a method for high-temperature purification of natural graphite by using light metal halide salt, which comprises the following steps: mixing a natural graphite raw material with composite light metal halide salt according to a mass ratio of 1: 0.1-0.3, the composite light metal halide salt comprising a mixture of chloride salt and fluoride salt; the method comprises the following steps: in a first stage, heating to 800-1000 DEG C under the protection of inert gas, and keeping the temperature for 1-2 hours; in the second stage, the atmosphere is switched into a reducing gas atmosphere, the temperature is increased to 1200-1400 DEG C, and heat preservation is conducted for 3-5 h; in the third stage, the temperature is raised to 1800-2000 DEG C by utilizing halogen gas generated by halogen salt pyrolysis, and heat preservation is carried out for 0.5-1 h; and performing acid pickling, water washing and vacuum drying on the pyrolysis product to obtain graphite. Compared with a traditional high-temperature purification method, the highest pyrolysis temperature is reduced by 500-800 DEG C, the energy consumption is reduced by 40-60%, the production cost is greatly reduced, and the economical efficiency and sustainability of the process are improved.

The invention discloses a method for enriching light metal ions in a pore channel based on carbon nanofiber / carbon fiber nano confinement, and belongs to the technical field of sample pretreatment, and the method comprises the following steps: S1, preparing a carbon nanofiber / carbon fiber confinement material; and S2, putting the carbon nanofiber / carbon fiber confinement material obtained in S1 into a light metal ion solution, and stirring. According to the method for enriching the light metal ions in the pore channel based on the carbon nanofiber / carbon fiber nano confinement, the carbon nanofiber / carbon fiber is used as a confinement fluid carrier, ultrapure water, methanol or n-hexane is used as an extracting agent, a chelating agent does not need to be introduced, the method is green and environmentally friendly, the mass transfer rate is increased, and the method is suitable for large-scale industrial production. Therefore, high enrichment of light metal ions in water is realized.

An electric motor (1) which is particularly suitable for use in a camshaft adjuster has a multi-part housing (2) which comprises a housing shell (3) made of a first material, in particular sheet steel, and a housing cover (4) made of a second material, in particular light metal, wherein a stator-rotor assembly (5) and an associated electronic module (10) including a printed circuit board (17) are accommodated in the space formed between the housing shell (3) and the housing cover (4), wherein the printed circuit board (17) is arranged three times, namely - firstly by formed material of the housing cover (4), - secondly by a motor contact (21) which is supported on the stator-rotor assembly (5), and - thirdly, by a pin (27) which is held in a plug module (20) which is inserted between the housing shell (3) and the housing cover (4), and is both mechanically fixed and electrically contacted.

The invention discloses an invisible light curtain hollowed-out light-transmitting metal wall surface mounting structure and a mounting method thereof.The invisible light curtain hollowed-out light-transmitting metal wall surface mounting structure comprises a plurality of box type invisible light curtain hollowed-out metal modules, a plurality of vertical rectangular steel frames are mounted on the surface of a wall body, and a plurality of rebound type bearing supports are mounted on each vertical rectangular steel frame; transverse rail square steel is installed on the rebound type bearing support, a slidable inserting and hanging base plate is installed on the back of each box type hidden lamp curtain hollowed-out metal module, and the slidable inserting and hanging base plates are in sliding connection with the two pieces of transverse rail square steel which are adjacent up and down. The vertical rectangular steel frame, the rebounding type bearing supports and the transverse rail square steel are assembled to form an overall base layer frame, the bearing supports are elastically adjusted to designated positions through the multiple sets of equidistant rebounding type bearing supports and internal spring structures of the rebounding type bearing supports and then anchored, so that the transverse rail square steel is rapidly clamped, inserted and installed in a limited mode, the space between cavities is adjustable, and the service life of the transverse rail square steel is prolonged. The base layer is high in surface flatness and stable in structure, and electromechanical pipelines are convenient to arrange.

The present invention discloses a method for extracting magnesium-lithium alloy using salt lake brine, which belongs to the technical field of light metal alloy material preparation. The method comprises the following steps: using ion adsorption, analysis, concentration and liquid adjustment on salt lake brine; using metal alkaline solution to adjust the pH of the solution, while performing a first precipitation, calcining the first precipitate to obtain MgO entrained with Li2O; using sodium carbonate solution to perform a second precipitation, dehydrating and drying the second precipitate to obtain a co-precipitated solid phase of MgCO3 and Li2CO3; adding CaO for vacuum thermal decomposition; adding a reducing agent and a catalyst for vacuum thermal reduction to obtain gas phase Mg and gas phase Li, using gas co-condensation technology to obtain crude Mg-Li alloy, and then refining and purifying to make Mg-Li alloys of different proportions. The present invention can effectively reduce process complexity and magnesium-lithium alloy manufacturing costs, reduce fixed asset investment, and ensure clean and environmental protection during the preparation process.

A control arm for a wheel suspension in a motor vehicle has a control arm body made of light metal. The control arm body has two parallel side walls. An elongated hole for an eccentric mount is provided in at least one side wall. The eccentric mount has a base plate with an elongated hole. An anchor body extending on the side of the edge of the elongated hole is provided at the rear of the base plate. At the front, the base plate has two eccentric stops projecting from the base plate. The eccentric mount is inserted with the anchor body into the elongated hole of the side wall and joined by pressing into the elongated hole.

The present disclosure is drawn to covers for electronic devices. In one example, a cover for an electronic device can include a light metal substrate including a first surface. A first micro-arc oxidation layer may be on the first surface of the light metal substrate, the first micro-arc oxidation layer can include a cationic dye bonded to the first surface via an anionic inorganic bridging compound.

The invention discloses a telescopic partition and an installation method thereof.The telescopic partition comprises a plurality of screens of the same structure, each screen comprises a rectangular frame, installation pipes and hollow pipes, the multiple installation pipes are fixedly arranged in the rectangular frame in parallel, the installation pipes are sleeved with the hollow pipes, and the hollow pipes can rotate on the installation pipes; color blocks are arranged on the outer surfaces of the hollow pipes, the screens can present different patterns by rotating the hollow pipes, pulleys are fixed to the top ends of the rectangular frames, guide rails are arranged at the top of a hall where the partition is located, the pulleys can roll in the guide rails so as to drive the screens to slide, the rectangular frames and the mounting pipes are made of light metal, and when the partition is unfolded, the screens are arranged in a straight line shape. When the partition is folded, the screen is arranged in a 1 shape. The partition can be stably stretched and folded in a large space, and the use range of the partition in the large space is expanded. The visual effect of the large-space screen is enriched, and the cost for replacing large-space partition pictures is reduced.

The application relates to a method for targeted growth of a high-temperature-resistant, low-thermal-conductivity, large-thickness and super-high-reflectivity laser protection coating on a light metal surface, and relates to the technical field of coating protection. Different ion source components are added in a solution, and electric parameters are regulated, so that a high-temperature-resistant, low-thermal-conductivity, large-thickness and super-high-reflectivity coating of a non-base oxide phase is generated in situ on the surface of a metal base through a solution ion directional reaction. The high-temperature-resistant ceramic phase has a high service temperature, the low thermal conductivity reduces the transmission of laser energy to the base, and the super-high reflectivity is helpful for consumption of laser energy, so that the laser protection capability of the coating is greatly improved. The thickness of the coating can reach 500 micrometers, the bonding strength is greater than or equal to 15 MPa, the thermal conductivity is as low as 0.35 W / (m*K), the reflectivity is as high as 92%, and there is no obvious damage under the irradiation of a laser with a power of 500 W for 60 seconds and the irradiation of a laser with a power of 800 W for 28 seconds, so that a new method is provided for laser protection.

Cylindrical body for injection moulding machines, intended to be used to generate a light metal semisolid slurry or in similar applications requiring a thermal mass body and precise temperature control.

The invention belongs to the field of automobiles, and particularly relates to a plastic-metal composite automobile tail door assembly and an automobile. The plastic-metal composite automobile tail door assembly comprises a tail door inner plate and a tail door outer plate; the tail door inner plate is made of light metal or light alloy; the tail door outer plate is made of plastic with a low linear expansion coefficient; the tail door inner plate and the tail door outer plate are connected through connecting glue in a gluing mode to form a cavity structure. Compared with the prior art, the problems that in the prior art, when an automobile tail door is made of a light alloy material, stamping is difficult, the cost is high, when the automobile tail door is made of a plastic material, the performance is poor, a large number of reinforcing structures and reinforcing pieces need to be arranged, and the lightweight effect is weakened are solved. According to the tail door assembly, the cavity structure is formed, light weight is guaranteed, meanwhile, reinforcement can be achieved through simple thickening, the mechanical performance of the tail door assembly can be improved through the formed cavity structure, and high-low-temperature deformation of products is reduced.

To solve a problem with a conventional filler rod supply device for supplying a filler rod used in TIG welding to a welding part that the two hands usually need to be moved separately so that workability is deteriorated.SOLUTION: A TIG welding filler rod supply assist jig of the present invention enables a filler rod to be supplied automatically without needing a human operation by using fluid such as compressed air as driving force for supplying a filler rod. A filler rod is arranged in a tube using a light-weight thin rod such as bamboo and light metal for a pillar. The TIG welding filler rod supply assist jig includes a filler rod supply brake for controlling the supply speed, a supply roller for bringing the filler rod to a welding point, and a heating device. Thereby, the filler rod is supplied to the welding point automatically and the supply work can be performed easily.SELECTED DRAWING: Figure 2

The present application belongs to the field of light metal plastic forming, and particularly relates to a device and method for preparing fine-grained magnesium alloy rod by asymmetric multi-directional shear extrusion. The wedge block combination in the present application can combine multi-directional shear extrusion deformation and differential speed torsional deformation, effectively weaken the magnesium alloy basal plane texture, and improve the mechanical properties of the magnesium alloy. While the magnesium alloy material is subjected to torsional extrusion in the torsional extrusion deformation zone, the sectional area of the channel gradually decreases, and the angle of the channel deflection is different, so that the frictional force of the magnesium alloy material on the surface of the convex and concave dies at the contact position is different, and the degree of torsional deformation is also different, so that the material realizes differential speed torsional deformation, and the grain refinement effect of the magnesium alloy rod is more remarkable. When the magnesium alloy material passes through the large and small concave dies, the deformation degrees of the magnesium alloy material are different due to the particularity of the structure, so that the grain refinement is effectively realized. At the same time, the flowability of the magnesium alloy material is also different, causing differential speed flow to deflect the c-axis, thereby weakening the texture.

The utility model discloses a lightweight screw machine motor structure. The motor structure comprises a machine head, a motor cylinder, a stator assembly, a rotor assembly and an air guide assembly. The motor cylinder is made of a light metal material, sleeves the outer side of the stator assembly and is fixedly connected with the machine head; the rotor assembly is rotatably arranged in the stator assembly, and a rotating structure for driving gas to flow is arranged on the rotor assembly; the air guide structure is arranged at the end, away from the machine head, of the motor barrel and used for guiding external air to flow in in the axial direction of the motor barrel. A plurality of heat dissipation channels extending in the axial direction are formed in the motor cylinder, an air flowing path matched with the rotating structure is formed, and air is driven by the rotor assembly to flow along the heat dissipation channels and is exhausted through the end, away from the air guide structure, of the motor cylinder. Through the arrangement, the heat dissipation efficiency of the motor is effectively improved, the overall quality is reduced, and the problems that a traditional screw motor is low in heat dissipation efficiency and heavy in structure are solved.

An embodiment of the present disclosure is a main plate which is attached to a robot arm and is capable of attaching and detaching a tool plate for holding a tool, the main plate including: a main plate body including a main body portion attached to the robot arm and having an attachment surface, and an insertion portion protruding from a surface opposite to the attachment surface of the main body portion and inserted into the tool plate; a piston member capable of reciprocating in a hole formed in the main plate body; and a sliding member disposed between the inner peripheral surface of the hole portion and the piston member, in which the main body portion and the insertion portion are integrally formed from a light metal or a resin, and a groove portion in which the sliding member is disposed is formed in the piston member.