A kind of gas suspension do not affected by pressurized gas with spherical hinge is without friction cylinder
The present invention relates to a kind of floating cylinder.
Common cylinder adopts mechanical seal usually, there is contact friction force between cylinder barrel and piston.
Traditional low rubbing cylinder relies on and improves machining accuracy, adopts special low-friction material or grease lubrication to reduce friction, but there is high, the difficult in maintenance and defect that the life-span is short of processing difficulties, cost; Or by improving seal form, reducing frictional force, as German FESTO company adopts special sealing technique to be applied to cylinder, adopting one-way sealing seal, there is very little resistance of taxing.SMC company of Japan adopts ball guide sleeve technology and Gap Sealing Technology, this low rubbing cylinder all has breakthrough at the uniform velocity property, high low pressure friction, high speed and high frequency, but there are some defects too, such as to radial Load Sensitive, complex structure, manufacturing difficulty are large, expensive.
Export the requirement of the aspects such as control, minute-pressure action control for meeting ultraprecise constant force, gas lubrication technology is realizing zero friction cylinder is applied." a kind of nothing friction cylinder with air-bearing " that be 201120080863.6 as number of patent application just discloses a kind of nothing friction cylinder according to air supporting principle design, minimum gap is left between cylinder barrel and piston, piston radial arranges the throttle orifice of even cloth, by the piston air feed that the piston rod of hollow and flexible pipe are in cylinder, and connected by ball pivot and make without friction cylinder can bear certain radial load and seizure of piston does not occur in cylinder.But it is complicated by the plenum system of hollow piston rod and flexible pipe, assemble loaded down with trivial details, not easy care, be optimized without friction cylinder afterwards, pressurized air in employing cylinder self cavity volume is as oiling agent, gas is introduced in gap, piston is made to be in complete state of suspension in the cylinder, piston does not contact each other with cylinder barrel, thus eliminates the frictional force in air cylinder structure between piston and cylinder barrel.But, no matter adopt which kind of plenum system, owing to leaving gap between piston and cylinder barrel, very large draught head is there is between the hyperbaric chamber of cylinder and low-pressure cavity, thus air pressure stream can be formed between gap, the direct air pressure film affecting piston and formed in gap by throttle orifice, on the other hand, the prerequisite of gas film behavior there is certain draught head in gap, and the gap air pressure near hyperbaric chamber one end raises, cause air-film thickness, pressure distribution uneven, all impact is caused to this nothing friction stability of cylinder, precision, bearing capacity.
Summary of the invention
In order to overcome the existing deficiency that high low pressure air-flow has an impact to air film, control accuracy is lower without friction cylinder, the invention provides a kind of gas suspension of the band spherical hinge that high low pressure air-flow has an impact to air film, control accuracy is higher of effectively avoiding without friction cylinder.
The technical solution adopted for the present invention to solve the technical problems is:
A kind of gas suspension do not affected by pressurized gas with spherical hinge is without friction cylinder, comprise cylinder barrel, piston, piston rod and spherical hinge, described piston is fixedly connected with by spherical hinge with piston rod one end, the described piston rod the other end establishes mounting hole, described cylinder barrel one end mounting base, the other end of described cylinder barrel installs end cap, described base is provided with gas source air inlet, described piston rod wears end cap, the rod chamber of described cylinder barrel is provided with air outlet, described piston radial arranges uniform throttle orifice, described outside piston cylinder is provided with a circle groove near rodless cavity side, radially blind hole is beaten above groove, get through hole again along piston wall to rod chamber direction and form pressure relief groove, mutually isolated between described pressure relief groove and throttle orifice.
Further, described pressure relief groove groove is provided with gradient near rodless cavity one end.
Further again, a circle pressure relief groove is distributed in piston wall, and a circle pressure relief groove contains at least two pressure relief grooves.
Or: at least two circle pressure relief grooves are distributed in piston wall.
Described piston is provided with the uniform throttle orifice of at least two group radial direction.
Described mounting hole is the tapped hole installing spherical hinge.
Mentality of designing of the present invention is: be designed with pressure relief groove at piston near one end of hyperbaric chamber, the gas flow entering piston and bore clearances from hyperbaric chamber is discharged to low-pressure cavity after certain crevice throttle damping is reduced pressure in pressure relief groove, does not affect the air film that on piston, throttle orifice is formed; Adopt pneumatic bearing to seal between piston rod and cylinder sleeve, eliminate the frictional force between piston rod and cylinder barrel.
Beneficial effect of the present invention is: effectively avoid that high low pressure air-flow has an impact to air film, control accuracy is higher.
Accompanying drawing explanation
Fig. 1 is that a kind of gas suspension do not affected by pressurized gas with spherical hinge is without friction cylinder schematic diagram.
Fig. 2 is piston schematic diagram.
Fig. 3 is Fig. 2 A-A view.
Fig. 4 is Fig. 2 C-C view.
Fig. 5 is that cylinder interior gas flows to schematic diagram.
Below in conjunction with accompanying drawing, the invention will be further described.
With reference to Fig. 1 ~ Fig. 5, a kind of gas suspension do not affected by pressurized gas with spherical hinge is without friction cylinder, comprise cylinder barrel 4, piston 7, piston rod 2 and spherical hinge 6, described piston 7 is fixedly connected with by spherical hinge 6 with piston rod 2 one end, described piston rod 2 the other end has the tapped hole 1 installing spherical hinge, described cylinder barrel 4 one end mounting base 9, the other end of described cylinder barrel 4 installs end cap 3, described base 9 is provided with gas source air inlet, described piston rod 2 wears end cap, the rod chamber of cylinder barrel 4 is provided with air outlet 10, described piston 7 radial direction arranges uniform throttle orifice 13, described outside piston cylinder is provided with a circle groove 11 near rodless cavity side, radially blind hole is beaten above groove 11, get through hole again along piston wall to rod chamber direction and form pressure relief groove 12, mutually isolated between described pressure relief groove 12 and throttle orifice 13.
Described pressure relief groove groove is provided with gradient near rodless cavity one end.One circle pressure relief groove is distributed in piston wall, and a circle pressure relief groove contains at least two pressure relief grooves.Or: at least two circle pressure relief grooves are distributed in piston wall.Described piston is provided with the uniform throttle orifice of at least two group radial direction.
Described rod chamber is low-pressure cavity 5, and rodless cavity is hyperbaric chamber 8.
In the present embodiment, minimum gap is there is between described piston and cylinder, described base and cylinder barrel end are fixed, described cylinder barrel, base form hyperbaric chamber in one end of piston, described end cap is arranged on cylinder barrel end, and described air-bearing, cylinder barrel form low-pressure cavity at the piston the other end, and low-pressure cavity cylinder barrel wall has air outlet O, source of the gas enters hyperbaric chamber from cylinder air inlet P1, promotes piston frictionless motion.
Piston rod two ends are connected with piston and exterior part by spherical hinge, make bear certain radial load without friction cylinder, avoid causing seizure of piston in cylinder because piston rod deflects.
Described piston radial is arranged the throttle orifice of even cloth, the quantity of throttle orifice can arrange one or more groups; Outside piston cylinder is designed with a circle groove near hyperbaric chamber side, above groove, radially beat blind hole, then gets through hole formation pressure relief groove along piston wall to low-pressure cavity direction, and one or more groups pressure relief groove is distributed in piston wall, does not communicate with between throttle orifice; As in Fig. 2, pressure relief groove groove nearly hyperbaric chamber one end becomes certain gradient, and therefore, the air-flow entering piston and cylinder gap from hyperbaric chamber directly flow in low-pressure cavity from pressure relief groove; The form that pressure relief groove also can be split into other, conveniently can derive the air-flow of hyperbaric chamber pressure people; Gas in hyperbaric chamber forms air film through throttle orifice between piston and cylinder gap, and air film gas fraction flows directly into low-pressure cavity along piston and bore clearances, and remaining flows into low-pressure cavity through pressure relief groove.And do not affect the air film between piston and cylinder barrel, as Fig. 3 from the gas that hyperbaric chamber enters gap.
Above-mentioned example is used for explaining the present invention, instead of limits the invention, and in the protection domain of spirit of the present invention and claim, makes any amendment and change, all fall into protection scope of the present invention to the present invention.