MXPA99000523A - Empa - Google Patents

Abstract

The present invention relates to a package for hydraulically sealing a piston rod traveling axially and oscillating in and out of a support in the form of a hydraulic shock absorber, comprising: a piston rod and a plastic sealing component elastic with a sealing edge resting against the piston rod, a sealing chamber with a cross section for receiving the sealing component, two elastic tension rings of packing cord placed diagonally opposite each other in the cross section of the chamber and supporting one with the other to radially tension the sealing component, each of the two rings rests against an inner side separated from the chamber, one of the two rings rests against a support of the sealing component and the other of the two rings also supports against a background part of the camera

Description

PACKING Description of the invention The invention relates to a package according to the main concept of claim 1. Such packages are preferably applied to seal the protruding end of an oscillating piston rod in the case of hydraulic shock absorbers, with the aim being to achieve, with a Reduced friction between the piston rod and the packing, a good stagnation of the hydraulic medium that is compressed at high pressure. DE-OS 2 206 771 discloses a package of the type under consideration. The disadvantage in the case of this packaging is that it is necessary to form with extreme precision the housing for the packaging by virtue of which this housing must be exactly adjusted to the cross section of the package. A further disadvantage is that at low temperatures only sufficient stagnation is achieved by a higher initial force, which leads to unnecessary frictional losses. The object of the invention is to simplify the structure of a package of the type under consideration and achieve, even at low temperatures, a good stagnation with reduced friction coefficients. This task is solved according to the invention by the features of claim 1. Advantageous structures and improvements are described in claims 2 to 5. The advantages achieved with the invention are particularly that a stagnation chamber can be provided. simple, because it has a rectangular cross section. In addition, it is possible to influence the stagnation in a simple manner by exchanging toroidal sealing rings of different qualities of material or of different sizes. It is particularly advantageous to hydraulically support the radial tightening of the packing element on the plunger rod, especially in the case of cold weather, even when the toroidal sealing rings no longer have a high elasticity at temperatures of around minus 40 ° Celsius. An exemplary embodiment of the invention is shown in the drawing and is described in more detail below. They show: Figure 1 a cut through the exit region of the piston rod of the shock absorber cylinder, and Figure 2 an enlarged representation of the package shown in Figure 1.

In the exemplary embodiment, the packaging for sealing a piston rod 1 that moves in an oscillating manner upon its entry into the open end of a cylinder 2 of a hydraulic vibration damper is described. Figure 1 shows an amplified part of this region. At the open end of the cylinder 2, a locking ring 3 is secured on a spring ring 4. Between the closing ring 3 and the cylinder 2 there is a gasket 5. A clamping ring 6 is inserted into a bore of housing of the closing ring 3, and is screwed with it by means of a thread. The clamping ring 6 carries in its inner central bore a sliding sleeve 7 for radially accommodating the piston rod 1. Between the annular surface 8 on the front side of the clamping ring 6 and the bottom of the blind hole in the closing ring 3 there is a space which, with the adjacent surfaces, forms a stagnation chamber 10. This stagnation chamber 10 with the parts that are mounted inside it is shown in amplified form in figure 2. In the region near the center of the stagnation chamber 10, on the outer circumference of the rod 1 of the plunger, it is found arranged a packing element 11. The inner jacket of this packing element 11 is configured in two directions in a slightly or markedly conical manner, so that the packing element 11 only rests against the outer circumference of the piston rod 1 with a surrounding stagnation edge 12. The packing elements 11 configured in this way have proved effective in sealing the piston rods 1 oscillating in the hydraulic shock absorbers. To tighten the packing element 11 against the piston rod 1, two toroidal sealing rings are used., 14. These toroidal seal rings 13, 14 have a smaller cross-sectional area together than the cross-sectional surface of the stagnation chamber 10. In the exemplary embodiment, the toroidal sealing rings 13, 14 in the non-tightened state have a tansversal section of circular shape. They are housed in such a manner in the stagnation chamber 10, that their cross sections abut diagonally to each other, as well as with the contact surfaces of the stagnation chamber 10 and the surface 15 of the back of the packing element 11. The cross section of the toroidal sealing rings 13, 14 is calculated so that the toroidal sealing rings 13, 14 require a space greater than the finally available cross section of the stagnation chamber 10, as they are against each other and against the contact surfaces with the stagnation chamber 10 and the surface 15 of the back of the packing element 11. The rings 13, 14 toroidal seals and the packing element 11 are introduced into the blind bore of the closing ring 3 before inserting the clamping ring 6, and are then arranged diagonally in such a way that the ring 13 obturator toroidal , that is to say, the toroidal obturator ring 13 with the smallest diameter is arranged on the outlet side of the piston rod, that is, in the exemplary embodiment, on the bottom 9 of the blind bore of the ring 3 of closing. When the retaining ring 6 is inserted into the blind bore of the locking ring 3 and is placed in its definite depth position, the toroidal sealing rings 13, 14 are pressed against each other and against the remaining abutting surface, which leads to a deformation of its cross section as shown in Figure 2. This tightening and deformation of the toroidal sealing rings 13, 14 results in the toroidal sealing ring 13 exerting a radial force on the packing element 11. The tightening of the toroidal sealing rings 13, 14 and the radial tightening of the packing element 11 which is achieved by hydraulically reinforcing it. The hydraulic pressure in the cylinder 2 of the damper is transmitted to the remaining chamber 16 of the stagnation chamber 10, through the guide gap between the sliding sleeve 7 and the rod 1 of the piston. Due to the impulse of the pressure on the back of the toroidal obturator ring 14, a wedge effect is produced here which produces a greater clamping pressure between the toroidal sealing rings 13, 14. This clamping pressure is further increased by virtue of the increase in pressure due to the pumping effect between the rod 1 of the plunger and the sliding sleeve 7, so that an increase of the same is also achieved, as desired, in this respect. the force of stagnation. The effect described above has particularly positive repercussions when the packaging is applied in cold weather, for example at minus 40 ° C. In the case of high subzero temperatures the internal elasticity of the rings 13, 14 toroidal obturators decreases rapidly, ie they only slowly take on their circular cross-sectional shape. However, since in the tight state they have the wedge shape that is shown, by the above-described effect it is nevertheless possible to achieve a good tightening of the packing element 11 against the rod 1 of the plunger. This also applies to the case that the toroidal obturator rings 13, 14 lose a part of their elasticity due to aging. Whether the toroidal sealing rings 13, 14 are formed from the same material, but with different mechanical properties of, for example, hardness, elasticity or cold resistance, as well as if they are made of different material, a great variability can generally be achieved. of the packaging with respect to the required properties. List of reference symbols 1. Vessel of the piston 2. Cylinder 3. Locking ring 4. Spring ring 5. Seal 6. Clamping ring 7. Sliding sleeve 8. Annular surface 9. Bottom 10. Stagnation chamber 11. Element of packing 12. Stagnation edge 13. O-ring toroidal 14. O-ring toroidal 15. Back surface 16. Camera

Claims (1)

1. CLAIMS Pack for hydraulically sealing a piston rod that slides axially inwards and out of a container, preferably a hydraulic shock absorber, comprising a packing element consisting preferably of elastic synthetic material, is configured with a stagnation edge that It abuts the plunger rod, is tightened by an elastomeric body and is disposed with the latter in a stagnation chamber, this packing being characterized by the fact that the tightening pressure is exerted by two toroidal sealing rings that abut one another diagonally in the cross-section of the stagnation chamber, which require a space that is larger than the remaining cross-section of the stagnation chamber when they are abuttingly adjacent to each other and with the contact surfaces of the stacking chamber. stagnation and the surface of the elem packaging Packaging according to claim 1, characterized in that at least one of the toroidal sealing rings has a circular cross-section. Packaging according to claim 1 or 2, characterized in that the toroidal sealing ring that abuts the surface of the back of the packaging element is located on the side by which the plunger rod leaves the chamber. stagnation Packaging according to one or more of claims 1 to 3, characterized in that the toroidal sealing rings have different mechanical properties, such as hardness, elasticity or cold resistance. Packaging according to one or more of claims 1 to 4, characterized in that the toroidal sealing rings are made of different material.