CN1194339A

CN1194339A - Leakless hydraulic cylinder

Info

Publication number: CN1194339A
Application number: CN97104609A
Authority: CN
Inventors: 张革
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-03-26
Filing date: 1997-03-26
Publication date: 1998-09-30

Abstract

The hydraulic cylinder includes piston, piston rod, cylinder, piston sealing ring, piston rod sealing ring, etc. It is different from other hydraulic cylinder in that the sealing for both piston and piston rod is performed through one kind of sealing part capable of deforming radically by the pressure of working medium, and that it uses cylinder of cold drawn steel tube no need of machining inner hole and reducing piston rod. Test shows that it has long service life.

Description

A kind of ne-leakage oil hydraulic cylinder

The present invention relates to a kind of oil hydraulic cylinder of ne-leakage.It can be widely used in coal, metallurgy, machinery etc. and adopt oil, water, and perhaps gas is the every field of medium.

Existing hydraulic pressure or pneumatic linear actuator, the leakage problems on its motive sealing surface also thoroughly do not solve.Domestic Sealing mostly is the rubber of different shape or the seal ring of polyurethane material, and its sealing mechanism is all the same basically, and leakage problems exists always.External building rubber compound seal ring is because superior materials require auxiliary equipment machining accuracy height, embody certain superiority on working life, but do not break through on the sealing mechanism, sealing effect is not very good yet, and cost an arm and a leg, so be very limited in the use.

Disclose a kind of expandable sealing ring in the Soviet Union SU1196580-A specification, the sealing ring is made of straight last end face and straight sidewall and outside bottom of protruding, and its cross section is rectangular basically.This seal ring is after the jack inside of needs sealing of packing into, and under the pretightening force effect of assembling, promptly the full annular area with end face on it contacts with inner wall of cylinder.Because the friction ractor of rubber and metal is bigger, therefore this contact will cause the initial movement of piston dumb.The particularly important is: when the pressure of sealing ring inner chamber is higher, the last end face of compressing seal ring is contacted with the metal cylinder barrel inwall firmly, and within it governor pressure unloaded after, end face and metal cylinder barrel inwall will bond together owing to the molecule affinity that high pressure produced on the seal ring, thereby influence the flexibility of jack action, in the jack that resets in those single-actings or by the weight of piston own, this defective is especially obvious.

Disclose a kind of piston seal among the Soviet Union SU1188430-A, this sealing is by the flexible fin maintenance low pressure seal performance of seal ring both sides, between two fins ring film is set, and ring film is under high pressure pressed to inner wall of cylinder, realizes high pressure sealing.Though this seal form greatly reduces the area of contact of seal ring and inner wall of cylinder, but still fail to solve sealing surface under high pressure and produce big affinity between the inner wall of cylinder and influence the problem of piston motion.

The inflatable seal apparatus of design in the China Patent No. 91202818.1, it is of value to the solution sealing problem, but the structure of seal ring is comparatively complicated, is difficult for processing.Solve rod seal problem poor effect.

The seal arrangement of design in the China Patent No. 91228381.5 thinks that after test seepage is serious in the seal arrangement itself, and sealing effect is bad.

The object of the present invention is to provide a kind of oil hydraulic cylinder that can keep long-time ne-leakage.The sealing configuration that this kind oil hydraulic cylinder adopts and cylinder barrel matching used with it and piston rod can produce good high low pressure sealing effect.

The object of the present invention is achieved like this:

A kind of ne-leakage oil hydraulic cylinder, it mainly is made up of parts such as cylinder barrel, piston, piston rod, piston packing, rod seal circles.Piston packing and rod seal circle all are cavitys, the U font ring bodies that can be out of shape with the pressure change of medium in the cylinder body.In above-mentioned U font ring bodies, when hydraulic cylinder works, inject working medium and make the ring bodies radial deformation, finish sealing function.Piston packing is that the compressive deformation external diameter increases.The rod seal circle is that internal diameter reduces behind the compressive deformation.Rod seal circle end face has the stepped shaft annular slot by inner radius, and groove width is greater than seal ring end face wall thickness, and placement one external diameter and width are consistent with seal ring cascade ring nominal size in the groove, the corresponding to anti-attrition compensated loop of internal diameter and piston rod nominal size.In addition, on the sealing surfaces excircle of rod seal circle, closely overlap an elastic ring, the width of elastic ring is identical with corresponding seal ring inner chamber width.The helical enhancement layer of the sealing internal surface of rod seal circle and the flexible material of its external diameter therebetween.Opening on rod seal circle U font surface is placed a width and is equaled U font Sealing A/F, and external diameter is identical with the seal ring external diameter, and the supporting ring of through hole is arranged on wall thickness.

Piston packing prolongs the axle center section and is U font structure, by the end stepped shaft annular slot is arranged at external diameter, groove width is greater than the seal ring side thickness, and it is identical with the internal diameter of cylinder nominal size to place an external diameter in the groove, and internal diameter and width are with the corresponding to anti-attrition compensated loop of the size of annular slot.At piston packing U font surface opening place, to place a width and equal U font A/F, internal diameter is identical with internal diameter of the seal ring, and the supporting ring of through hole is arranged on wall thickness.

Because the present invention has taked technical measures as above technically, therefore, when in the active chamber of hydraulic pressure or pneumatic linear actuator, being full of high-pressure working medium, the performance of bearing pressure action in the seal ring and expanding, the sealing surfaces of seal ring is closely contacted with cylinder barrel or piston rod, thereby obtain reliable high pressure sealing performance.The initial sealing of seal ring guarantees by the magnitude of interference of seal ring sealing surfaces.Owing to can control magnitude of interference indirectly, be very easily so adjust by the width of control supporting ring.The present invention in force, the material of seal ring adopts the strong glue kind of the little wear resistance of friction ractor, though widened seal f ace width so in the use, the minimum starting pressure that also makes oil hydraulic cylinder is less than the NBS several times.In sealing configuration of the present invention, the wearing and tearing of sealing surfaces are that the radial deformation by Sealing compensates automatically, so high life goes out national criterion numeral doubly in test.470,000 commutations, in the test of stroke 300 kms, interior seepage index is zero in the front and back of life test.Sealing configuration of the present invention has very strong contamination resistance.As in test, seal ring of the present invention is packed in the hydraulic prop that the colliery uses, add the footpath at rod end chamber and cross 80 gram coal dusts and the 10 gram sands that 120 mesh sieve mesh screens are crossed, with the upright action of 38MPa working pressure 8000 times, 6400 meters of strokes, Sealing of the present invention often damages undoubtedly, and has kept the sealability of ne-leakage.Rod seal circle of the present invention, (the minor diameter roughness Ra=6.3 of major diameter-minor diameter=0.45mm) and in the reducing leakage test of piston rod with 0～20MPa working pressure, stroke 1450m, the ne-leakage after 5300 times that commutates has been obtained the satisfactory sealing effect.The above-mentioned test effect of the present invention all is to adopt the cold-drawn cylinder barrel, and the cylinder barrel internal surface is not done and made under the situation of any machining.With traditional cylinder barrel bore hole, honing technique and bore hole, rolling technology is compared and has been saved a large amount of machining workloads, and it is significant saving production cost.

Below in conjunction with accompanying drawing a kind of ne-leakage oil hydraulic cylinder of the present invention is further described:

Fig. 1 is the half section structure diagram of present embodiment.

Piston 6 adopts screw thread to be connected with piston rod 7 among Fig. 1.Be with a piston seal coil assembly respectively at the two ends of piston 6, and fixing by nut 1 with piston 6.The piston seal coil assembly is made up of seal ring 3 supporting rings 4 anti-attrition compensated loops 5.The seal ring section is the U font, in the outer radius of one end one ring ladder groove is arranged, and places annular anti-attrition compensated loop 5 in the ring ladder groove, and the external diameter of anti-attrition compensated loop 5 is identical with the internal diameter of cylinder barrel 2, and the width of anti-attrition compensated loop 5 is greater than the end face wall thickness of seal ring 3.Place a supporting ring 4 at the opening end of U font seal ring 3, on the wall thickness of supporting ring 4 through hole is arranged.By the guide sleeve 11 that is threaded, in the interior step hole of guide sleeve 11, place a rod seal coil assembly in the bottom of cylinder barrel 2, and fixing by nut 8 with guide sleeve 11.The rod seal coil assembly is made up of supporting ring 9, rod seal circle 12, elastic ring 10 and anti-attrition compensated loop 14.Opening at U font rod seal circle 12 is placed supporting ring 9, on the wall thickness of supporting ring 9 through hole is arranged.There is the ring ladder groove at sealing surfaces two ends at rod seal circle 12, place anti-attrition compensated loop 14 in this groove, and the width of anti-attrition compensated loop 14 is greater than the end surface thickness of seal ring 12.Be with elastic ring 10 on the excircle of the sealing surface of U font rod seal circle 12, the width of elastic ring 10 is more smaller than the A/F of seal ring 12, and elastic ring 10 axially is the state of moving about in seal ring 12.Between the sealing surface inner and outer surface of seal ring 12, accompany spiral helicine elastic rope enhancement layer.

The operating principle of a kind of ne-leakage oil hydraulic cylinder of the present invention such as Fig. 1.

Do when piston rod and to stretch out when action: the A chamber feeds working medium, pressure by zero to working pressure be a change procedure.When pressure is zero or when very little, the interference with cylinder barrel 2 internal diameters realizes by seal ring 3 in the sealing of piston.Sealing is along with the A cavity pressure increases, and by the inlet opening that communicates with A, C chamber, the pressure that enters the C chamber together raises.Therefore pressure action promotes seal ring and outwards expands in the active force that the surface of seal ring produces in the C chamber, so the piston cavity sealing force is to finish sealing automatically along with the pressure increase and decrease of working medium.

Do when piston rod and to stretch out when action: the discharge opeing of B chamber, pressure changes with flow velocity, and it is very low to be considered as pressure.The piston seal principle of tailpiece of the piston rod is identical with the piston seal of rodless cavity.And rod seal is finished low pressure seal by pressure and elastic ring 10 that interference between seal ring 12 and the piston rod 7 produces jointly with the pressure that seal ring 12 produces.

When piston rod was done the withdrawal action: the sealing principle in B chamber was identical with aforesaid A chamber, and the sealing principle in A chamber is identical with aforesaid B chamber.

Evidence, sealing configuration of the present invention are applied in the high, medium and low various pressure range and have all obtained desirable sealing effect.

The foregoing description only is used to illustrate spirit of the present invention, and a kind of ne-leakage oil hydraulic cylinder of the present invention not only can be applied on the double acting cylinder, also can be applied on the single-acting cylinder simultaneously.Rod seal can be adopted when on single-acting cylinder, using, also piston seal can be adopted.

Claims

1, a kind of ne-leakage oil hydraulic cylinder, comprise cylinder barrel, piston, piston rod, piston packing, rod seal circle, it is characterized in that, can be with internal pressure the U font ring bodies of radial deformation, in above-mentioned U font ring bodies, when hydraulic cylinder works, the pressure that injects working medium makes the ring bodies radial deformation, closely contact and finish sealing function with cylinder barrel or piston rod, piston packing distortion back external diameter increases, and the rod seal circle is out of shape the back internal diameter and reduces.

2, as claim 1 described piston seal ring, it is characterized in that the seal ring section is a U font structure, external diameter is the ladder annular slot by the end, and ladder width is greater than piston packing end face wall thickness.

As claim 1 or 2 described piston packings, it is characterized in that 3, the seal ring external diameter is by placing the annular anti-attrition compensated loop identical with channel section in the end face ladder annular slot.

As claim 1 described piston packing, it is characterized in that 4, the U font opening of Sealing is placed a supporting ring, the supporting ring width equals the inner opening width of Sealing, and the supporting ring internal diameter is identical with internal diameter of the seal ring, and the hole of running through wall thickness is arranged.

As claim 1 described rod seal circle, it is characterized in that 5, the seal ring section is a U font structure, the footpath is the ladder annular slot by the end within it, and ladder width is greater than the seal ring end surface thickness.

6, as claim 1 or 5 described rod seal circles, it is characterized in that, place the annular anti-attrition compensated loop identical in the ladder annular slot of the outer end of internal diameter of the seal ring with channel section.

As claim 1 or 5 described rod seal circles, it is characterized in that 7, closely be with an elastic ring on the sealing surfaces excircle of seal ring, the width of elastic ring is slightly less than corresponding seal ring inwall width.

8, as claim 1 or 5 described rod seal circles, it is characterized in that the opening of U font Sealing is placed the inner opening width that a width equals U font Sealing, external diameter is identical with the seal ring external diameter and the supporting ring of through hole arranged on wall thickness.

9, as claim 1 or 5 described rod seal circles, it is characterized in that, accompany spiral helicine elastic rope enhancement layer in the middle of the sealing surfaces of seal ring and its external diameter.