CN205025863U

CN205025863U - Hydraulic cylinder piston plane is from seal structure

Info

Publication number: CN205025863U
Application number: CN201520703974.6U
Authority: CN
Inventors: 汪立平
Original assignee: Jiangsu Hengli High Pressure Oil Cylinder Co Ltd
Current assignee: Jiangsu Hengli Hydraulic Co Ltd
Priority date: 2015-09-14
Filing date: 2015-09-14
Publication date: 2016-02-10
Anticipated expiration: 2025-09-14

Abstract

The utility model discloses a hydraulic cylinder piston plane is from seal structure, D face and E face contact with each other form a closed -loop, wherein the smooth finish of D face between 3.0 -3.3, and the perpendicularity more than or equal to 0.05 between the thread face on the piston rod, E face smooth finish is between 1.5 -1.7, and the perpendicularity more than or equal to 0.05 between the thread face of piston. In this way, the utility model discloses can only screw up back piston pole D face by the piston and with piston E face because certain plastic deformation that the pretightning force produced finally reaches sealed effect, form the system that the face contact that does not need the sealing member only to lean on work piece itself is gone on sealing, these sealed characteristics are that pressure is high more, and sealed original paper is just big more in the packing force of contact surface, and sealing performance is just also good more.

Description

Hydraulic cylinder piston plane self sealing structure

Technical field

The utility model relates to hydraulic cylinder piston field of sealing technology, particularly relates to a kind of hydraulic cylinder piston plane self sealing structure.

Background technique

Oil cylinder internal leakage is one of modal fault of oil hydraulic cylinder.The reason of internal leakage is caused to mainly contain a lot:

1. oil cylinder processing problems, as too low in inner hole of cylinder roughness, endoporus cylindricity is too low, and on piston, groove degree of finish is poor.

2. sealing is selected unreasonable, or Sealing is aging, inefficacy.

3. oil cylinder uses problem, and the too high oil cylinder that causes of system pressure swells, and overload, causes cylinder bore to be pulled.

General Normal hydraulic oil cylinder must design seal ring to prevent from producing internal leakage in cylinder efficient process when designing on piston, and internal leakage has two-part: 1 is from the clearance leakage between piston and cylinder barrel; 2 is from the clearance leakage between piston and piston rod.

Often because actual use working pressure is too high, the seal ring of 2 internal leakages place can be damaged in oil hydraulic cylinder and cause oil cylinder internal leakage.

Model utility content

The technical problem that the utility model mainly solves is to provide a kind of deficiency overcome in the design of existing piston seal, can ensure the hydraulic cylinder piston plane self sealing structure that the normal safe of oil cylinder runs.

For solving the problems of the technologies described above, the technological scheme that the utility model adopts is: provide a kind of hydraulic cylinder piston plane self sealing structure, comprise: piston rod and piston, one end face of setting piston rod is D face, one end face of piston is E face, D face and E face contact with each other formation one closed loop, and wherein the degree of finish in D face is between 3.0-3.3, and the perpendicularity between the flank of thread on piston rod is more than or equal to 0.05; E face degree of finish is between 1.5-1.7, and the perpendicularity between the flank of thread of piston is more than or equal to 0.05.

In the utility model preferred embodiment, E face is provided with step surface, and the width of this step surface is 0.25mm-0.5mm.

In the utility model preferred embodiment, the end grain in D face and E face is concentric circles texture.

In the utility model preferred embodiment, E face is provided with lubricating layer.

In the utility model preferred embodiment, the pretightening force in E face is greater than the thrust destroying sealing surface.

The beneficial effects of the utility model are: the utility model cancels seal ring, only tighten back piston bar D face and piston E face by piston because certain plastic deformation of producing of pretightening force, finally reach the effect of sealing, define a kind of Sealing that do not need and only contact by the face of workpiece itself system carrying out sealing, the feature of this sealing is that pressure is higher, sealing original paper is larger in the impacting force of surface of contact, and sealability is also better.

Accompanying drawing explanation

In order to be illustrated more clearly in the technological scheme in the utility model embodiment, below the accompanying drawing used required in describing embodiment is briefly described, apparently, accompanying drawing in the following describes is only embodiments more of the present utility model, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings, wherein:

Fig. 1 is the structural representation of a preferred embodiment of piston rod and piston in the utility model hydraulic cylinder piston plane self sealing structure;

Fig. 2 is the structure for amplifying schematic diagram in E face in the plane of hydraulic cylinder piston shown in Fig. 1 self sealing structure;

Fig. 3 is the ssembly drawing of the plane of hydraulic cylinder piston shown in Fig. 1 self sealing structure;

In accompanying drawing, the mark of each parts is as follows: 1, piston rod, and 2, piston, 3, D face, 4, E face, 5, flank of thread, 6, step surface.

Embodiment

Be clearly and completely described to the technological scheme in the utility model embodiment below, obviously, described embodiment is only a part of embodiment of the present utility model, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making other embodiments all obtained under creative work prerequisite, all belong to the scope of the utility model protection.

Refer to Fig. 1, the utility model is embodiment comprise:

A kind of hydraulic cylinder piston plane self sealing structure, comprising: piston rod 1 and piston 2, and an end face of setting piston rod 1 is D face 3, and an end face of piston 2 is E face 4.

Prior art is added with seal ring between piston rod 1 and piston 2, and seal ring is cancelled by the utility model, and the E face 4 in the D face 3 and piston 2 of only tightening back piston bar 1 by piston contacts with each other formation one closed loop, realizes the effect of sealing.

Wherein the degree of finish in D face 3 is between 3.0-3.3, and the perpendicularity between the flank of thread 5 on piston rod 1 is more than or equal to 0.05.

E face 4 degree of finish is between 1.5-1.7, and the perpendicularity between the flank of thread 5 of piston 2 is more than or equal to 0.05.So process a step surface 6 to ensure its behavior tolerance in E face when machining screw simultaneously.The width of this step surface 6 is 0.25mm-0.5mm, as shown in Figure 2.

E face 4 is provided with lubricating layer.On piston 2, oil lubrication must be coated in E face 4, to reduce piston and plunger rod contacts face friction factor, and will give the pretightening force enough with piston.Because piston has at the P of the sealing surface that is damaged the possibility producing certain gap to piston during thrust and rod seal face, this just likely produces internal leakage.So pretightening force must be greater than P that piston bears to thrust, be that sealing surface ensures sealing, as shown in Figure 3.

Because want the Rz value of applanation surface roughness just to have first condition of composition closed loop.And sealing surface surface roughness determines according to design code and the required most economical process means of sealing intensity (sealing grade) that will reach to ensure to reach sealing pair defined, so be a specified value, increase roughness then seal degree does not reach, reduce roughness, then manufacture cost increases, uneconomical, therefore can only allow piston E face by pretightening force to flatten the Rz value in piston rod D face, composition closed loop.

If sealing surface surface irregularity is too large, also can only cause localized contact by overcoming Rz value, this localized contact differs and creates the condition of composition seal ring surely.So sealing surface surface irregularity is an independent independently factor.

Processing texture has various ways, but is concentric circles texture for the end grain in the optimal D face of sealing surface and E face.When for radial or any direction texture, can could form closed loop by overcoming Rz value, so it is not a crucial factor

Specific pressure is an important factor, changes the balance that specific pressure can make various factors reach new, thus keep the sealing of sealing pair during the change of surface roughness, surface texture etc.So specific pressure plays a part very important in sealing pair, some other factor is all subordinated to it, and therefore specific pressure is also an independent independently factor.

Two side pressure difference problems, in fact a sealing load problem can be regarded as, because just there is not a sealing problem when two side pressure are equal, and pressure is an initial parameter, the change of pressure will cause the change of series of factors, just need the difference according to pressure and to change and can the change of specific pressure make be driven plain as surface roughness and create the formation condition forming minimum sealing condition-closed loop as specific pressure.Therefore pressure reduction is a prevailing independent factor.

The utility model cancels seal ring, only tighten back piston bar D face and piston E face by piston because certain plastic deformation of producing of pretightening force, finally reach the effect of sealing, define a kind of Sealing that do not need and only contact by the face of workpiece itself system carrying out sealing, the feature of this sealing is that pressure is higher, sealing original paper is larger in the impacting force of surface of contact, and sealability is also better.

The foregoing is only embodiment of the present utility model; not thereby the scope of the claims of the present utility model is limited; every utilize the utility model description to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical field, be all in like manner included in scope of patent protection of the present utility model.

Claims

1. a hydraulic cylinder piston plane self sealing structure, comprise: piston rod and piston, one end face of setting piston rod is D face, one end face of piston is E face, it is characterized in that, D face and E face contact with each other formation one closed loop, and wherein the degree of finish in D face is between 3.0-3.3, and the perpendicularity between the flank of thread on piston rod is more than or equal to 0.05; E face degree of finish is between 1.5-1.7, and the perpendicularity between the flank of thread of piston is more than or equal to 0.05.

2. hydraulic cylinder piston plane self sealing structure according to claim 1, it is characterized in that, E face is provided with step surface, and the width of this step surface is 0.25mm-0.5mm.

3. hydraulic cylinder piston plane self sealing structure according to claim 1, is characterized in that, the end grain in D face and E face is concentric circles texture.

4. hydraulic cylinder piston plane self sealing structure according to claim 1, it is characterized in that, E face is provided with lubricating layer.

5. hydraulic cylinder piston plane self sealing structure according to claim 1, is characterized in that, the pretightening force in E face is greater than the thrust destroying sealing surface.