DE8117274U1 - HYDRAULIC TWO TUBE TELESCOPIC SHOCK ABSORBER - Google Patents

Description

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The invention relates to a hydraulic two-tube telescopic shock absorber, the cylinder space of which is divided into two working spaces by a piston provided with valves is, of which the lower one is in communication with a compensating chamber surrounding the cylinder chamber via valves arranged in the base piece, and one in the cylinder wall or a plurality of bores connecting the cylinder space with the compensation space are provided which have an additional Form 3ypass, which is opened or closed depending on the piston movement, with the holes opening the side of the compensation chamber are surrounded by a sleeve-shaped part. This bypass influences the damping characteristics depending on the damper travel.

The sleeve-shaped surrounding the bores in the cylinder wall Part is formed in DE-PS 1 253 073 by a valve λνί ^ βηΰβη elastic tube piece, the axially by means of annular springs located axially on both sides next to the hose section and arranged in grooves in the cylinder wall is fixed. In addition to the operational safety through the prevention of the axial movement of the sleeve-shaped part is also intended to prevent foam formation through the laminar flow of liquid achieved through the closure member will. Such a known closing element, which acts as a valve, is, in a special case, also the suction prevent air from entering the working cylinder. If there is a flow of liquid through the bores afterwards

The liquid enters the equalizing chamber at the closing element both up and down. This leads to foaming and mixing of the liquid with air, if only the upper exit area on the closing element is already above the liquid level. The known closure member is expensive both in production and in assembly. The lifespan is due the known material uses limited.

In DE-PS 650 195, the bores in the cylinder wall of a shock absorber are surrounded by a sleeve, which prevents the liquid from splashing upwards. Because of the small downward expansion of the sleeve the exiting liquid will foam up and the sleeve would not suck in air either impede. The same is also the case with the arrangement according to DE-AS 1 296 026.

The invention is based on the object of making provisions for the bores in the cylinder wall through which not only prevents the sucking in of air in a simple manner, but also prevents the foaming of the Liquid or mixing of the liquid with air is avoided.

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According to the invention this is achieved in that the sleeve-shaped Part just above the bores is airtightly connected to the cylinder wall and as a tube down to the inside an area of the compensation chamber that is constantly filled with damping fluid is sufficient. In this way, with one low liquid level in the compensation area, namely below the bores in the cylinder wall, that no air is sucked into the working cylinder and that when the liquid overflows from the working cylinder in the compensation space this reaches at least without significant foam formation in the compensation space below the liquid level.

The tube is expediently made of metal and forms an intermediate space between it and the cylinder wall. This execution has the advantage of a long service life in any case and thus also long operational reliability, there the pipe is not subject to change. In terms of production, the pipe is easy to connect to the cylinder wall, when the tube at its end lying above the bores has the same diameter as the cylinder wall in its inner diameter and the connection by means of shrinking, Gluing or the like. Takes place.

To allow the oil flow in the compensation chamber in the vertical direction, especially in the lower part of the compensation chamber through the sleeve-shaped part to oppose as little resistance as possible, is according to a further feature of the invention

proposed that the sleeve-shaped part forms a groove-shaped channel in the region of the bore and the rest Urafangbereich rests on the cylinder wall.

The groove-shaped channel expediently runs around in a spiral the cylinder wall down. This has the advantage that the circular movement of the oil causes another Reassurance occurs.

The invention is explained in more detail using exemplary embodiments. Show it :

1 shows a cross section through a twin-tube shock absorber,

2 shows a further simplified cross section of the lower section,

Fig. 3 is a section along line III-III in Fig.

and
4 shows the lower section of a shock absorber

with another embodiment.

The working cylinder 2 of the shock absorber 3 is through the piston 4 in an upper 6 and a lower working space divided. The piston rod 10 of the piston 4 is sealingly in an upper end piece 12 of the working cylinder 2

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guided. At the lower end, the working cylinder is closed by a base piece 14. The cylinder wall 16 of the Working cylinder 2 is in tight connection with the upper end piece 12 and the bottom piece 14.

The working cylinder 2 is concentrically surrounded by a tube 18, between which and the cylinder wall 16 the compensation chamber 20 is formed. The tube 18 is through at the lower end a bottom part 22 completed, while the upper end of the tube 18 with the upper end piece 12 in connection stands. The compensation space 20 is only schematically indicated valve openings 24 in the bottom piece 14 with the lower work space 8 in connection. Valve openings 26 are also provided in the piston 4. On the piston rod 10 there is still a stop ring 28.

The effectiveness of the shock absorber can be assumed to be known. Next to the valve openings 24 and 26 in the bottom piece or piston 4, an opening 30 is provided in the cylinder wall 16, which is used for the path-dependent control of the damping or a path-dependent damping characteristic results. Of course, several bores can be distributed around the circumference and, in particular, can also be arranged one above the other. Is moving the piston 4 upwards from a lower position, e.g. through the valve openings 24 and 26, the flow of which is correspondingly matched to one another, initially liquid

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pressed through the bore 30 into the compensation chamber 20. When the piston 4 continues over the bore 30 moved upwards, then liquid is sucked through the bore 30 from the compensation chamber 20 into the working chamber 8.

A tube 32 is arranged around the cylinder wall 16 at a distance therefrom, which extends from the bore 30 to extends below, namely up to an area of the compensation chamber 20, which is constantly filled with damping fluid is filled. In the exemplary embodiment, the tube 32 extends into the area of the base piece 14. The tube 32 is on its above the bore 30 lying end 34 is reduced in diameter so that it is with its inner diameter rests against the cylinder wall 16 and is connected to it in an airtight manner by shrink fitting or other methods, The tube 32 prevents air from flowing out of the air when the piston 4 is moved upward beyond the bore 30 Compensation chamber 20 is sucked in when the liquid level should have dropped below the bore 30. on the other hand is when the piston 4 moves downward above the bore 30 liquid through the bore 30 into the Compensation chamber 20 pressed. This moves down into the space between the cylinder wall 16 and tube 32, that is towards the bottom of the compensation chamber, so that no foaming occurs. The tube 32 is expediently made made of metal or comparable materials that are not subject to physical changes.

In FIGS. 2 and 3, in which the same reference numerals are used for the same parts, the sleeve-shaped part, ie the tube 32 ¹ over most of its circumference, has an inner diameter such that it rests against the cylinder wall 16. Only in the area of the bore 30 does the tube 32 'form a groove-shaped channel 42 with the cylinder wall 16 through a bulge 40. The channel 42 extends in a straight line downward over the entire length of the tube 32'. The compensation chamber 20 or the oil flow in this is thus least influenced by the pipe 32 '.

In Fig. 4 the bulge 40 'of the tube 32' 'runs spirally, so that there is a groove-shaped channel 42 'running spirally downwards, which is used for calming contributes to the flow of oil.

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summary

In the case of a two-tube telescopic shock absorber with a hole in the cylinder wall 16 of the working cylinder 2 for travel-dependent Control of the damping, the bore 30 is surrounded by a tube 32 which is just above the Bore 30 is connected to the cylinder wall 16 airtight and down to a constantly with damping fluid filled area of the compensation space 20 is sufficient.

Claims (5)

• · M ti * · · Γ) f «·· I I Il June 9, 1981 6243 Applicant: Adam Opel Aktiengesellschaft 6090 Rüsselsheim Hydraulic twin-tube telescopic shock absorbers Claims 1. Hydraulic twin-tube telescopic shock absorber, the cylinder space of which is controlled by a piston provided with valves is divided into two working spaces, of which the lower one via valves arranged in the base piece with one of the The compensation chamber surrounding the cylinder chamber is in communication and one or more of the in the cylinder wall Bores connecting the cylinder chamber with the compensating chamber are provided, which have an additional Form a bypass that is opened or closed depending on the piston movement, with the bores opening the side of the compensation chamber are surrounded by a sleeve-shaped part, characterized in that the sleeve-shaped part just above the bore (30) is airtight with the cylinder wall (16) is connected and as a tube (32) down to in I I I I I _t a ι «· j ·· t an area of the compensation chamber (20) that is constantly filled with damping fluid is sufficient. 2. Telescopic shock absorber according to claim 1, characterized in that the tube (32) is made of metal and has a space between it and the Forms cylinder wall (16). 3. Telescopic shock absorber according to claim 1 and 2, characterized in that the tube (32) extends down into the area of the base piece (14). 4. Telescopic shock absorber according to claim 1 and 3, characterized in that the tube (32 *) in the area the bore (30) forms a groove-shaped channel (42) and in the remaining circumferential area on the cylinder wall (16) is applied. 5. Telescopic shock absorber according to claim 4, characterized in that the groove-shaped channel (42 ¹ ) runs spirally around the cylinder wall (16) downwards.