DE4002882C1 - Hydraulic shock absorber with damping liq. contg. cylinder - has several passages and couplers, each on different partial diameters - Google Patents

Abstract

The hydraulfc shock absorber cylinder (1) includes a piston (3) with non-return throttle valves (13) for controlled fluid transfer in an axial direction across the piston. The piston rod (2) has a tubular end which protrudes through the piston. A hollow piston-shaped body (11) is attached to the piston rod end and includes two chambers (8a, 8b) which are separated by an elastic membrane (9). The two chambers are linked to both cylinder chambers (4, 5) for secondary damping. USE/ADVANTAGE - For a car suspension with decoupling of HF short stroke road induced vibration.

Description

The invention relates to a hydraulic Vibration damper for motor vehicles with a damper liquid containing cylinder, one therein sealed immersed axially displaceable arranged piston rod and one attached to it Piston that holds the cylinder in two work spaces divides, the cylinder and the piston rod each a fastening device for fastening to the Have body or on the wheel suspension, wherein in A piston is provided in the region of the piston divided into two sub-chambers by a membrane and is sealed against each other, with a partial chamber via a channel with the upper work space and the second sub-chamber connected to the lower work area is.

They are already hydraulically damping vibration dampers known (e.g. GB-PS 21 58 549), in which the piston rod of a vibration damper via a bearing on the Body is attached. Have such bearings rubber-elastic elements to absorb vibrations. When using bearing eyes are usually flat if elastic rubber elements are interposed. Such fastening devices have the disadvantage that that with high-frequency excitation through the road,  especially uncomfortable with small amplitudes Act. This is, for example, because the Rubber mounting parts of the vibration damper on the driver structure and harden on the wheel suspension and thus Vibrations and noise in the passenger compartment wear. In addition, the high input frequency and a small stroke movement the flawless mutual work of damping or kickback valves increasingly worse, so that also a uncomfortable hardening of the vibration damper lies.

Vibration dampers are also known (FR-OS 24 25 585), which are independent of the damping piston, however, a chamber is provided in the damping piston, which is divided by a membrane and a half each connects with one workspace each. By using it of one inlet and one drain hole each the risk that the membrane jerkily into the respective End position is brought. This will be in the Fahrbe generated jerky jumps in damping, that reduce driving comfort, cause noise and shorten the life of the vibration damper.

In addition, suspension systems are known (e.g. DE-AS 11 64 850, DE-GM 70 16 060), in which chambers for ver Change of volume changes in the system connected are. The chambers are each with one on their Provide circumference firmly and tightly clamped membrane, see above that by axial movement of the membrane relative to the one volume equalization can. The disadvantage is that the walls of the chambers a curved but continuous curvature have radius, so that a sudden, jerky Striking the membrane, even when using several Holes cannot be avoided and that it does to jumps in damping, noise and ver reduction in driving comfort and lifespan.

The object of the invention is a vibration damper so that high-frequency, small-stroke Road excitations are decoupled from the vehicle body, without the damping effect with larger stroke loading movements is significantly reduced that jerky Jumps in damping can be avoided.

To solve this problem, the invention provides see that at least two channels and at least two Connections are provided, each on different which pitch circle diameters are arranged, the the inner surfaces of the chamber with openings run at different angles to the central axis.

It is advantageous in this training that frequency dependent damping characteristics are generated can. If the vibration damper is at a higher Frequency excited with small amplitude, so are mainly the two sub-chambers with damping liquid filled and emptied alternately. The The membrane reaches the corresponding one Chamber wall to the system without the damping valves work. Is the small-stroke and generally high leave frequency excitation range, that is, takes place a low frequency, high amplitude Excitation, the membrane comes to rest on the chamber and the damping valves of the piston work in the conventional type, whereby the necessary pressure build-up for the damping force on the damping valves of the Piston. By an appropriate number of Channels and connections become a jerky plant Membrane avoided; so that damping force jumps and avoided noise, so that comfort is maintained becomes.

According to another essential feature, that the chamber is arranged in the piston.

In addition, it is particularly cheap form the chamber axially in a separate component  arranged the piston and attached to the piston rod. In this application, the actual piston nut omitted, so that the separate component instead of Piston nut takes over the safety function.

To achieve a required minimum Damping is a further embodiment of the invention provided that the channels and / or the connections as Throttle is formed.

To achieve a harmonious increase in strength when Transition from reduced damping in the work area the membrane for total damping in the work area Damper valves in the rebound and compression stages are in progress staltung the invention provided that the cross section the channels and the connections are the same or below are different.

Embodiments of the invention are in the drawings shown schematically. It shows

Fig. 1 shows a vibration damper in section, wherein the chamber are arranged together with the diaphragm as a separate component on the piston,

FIGS. 2 to 4 each show a further embodiment of a membrane.

The vibration damper shown in Fig. 1 consists essentially of the cylinder 1 , the piston 3 and the sealed in the cylinder 1 immersed, axially slidably arranged piston rod 2 , which carries the piston 3 . The piston 3 divides the cylinder 1 into the upper 4 and the lower working space 5 . The piston 3 has spring-loaded throttle channels 13 for generating damping forces.

In the area of the piston 3 , a separate component 11 is connected to the piston rod 2 , the interior of which forms a chamber 8 for receiving a membrane 9 . The chamber 8 b is connected via the connection 12 to the lower working space 5 , the chamber 8 a has pull over the channel 10 to the upper working space 4th

In the case of small-stroke and generally high-frequency relative movements of the fastening devices 6 and 7 , the diaphragm 9 can be deflected appropriately to both sides of the inflowing or outflowing damping fluid without the spring-loaded throttle channels 13 taking up their function.

In FIGS. 2 and 3, a further separate construction is shown in part 11, said part chambers 8 a and 8 b via several channels 10 and a plurality of connections 12 are connected to the respective working space 4 and 5 respectively. A corresponding arrangement of the channels 10 or the connections 12 allows the membrane 9 to be gently applied to the respective chamber wall. In Fig. 2 there is a central channel 10 and a central connection 12 is provided in each case, while Fig 3, only channels 10 and connections 12 providing the outer region of the chamber 8..

FIG. 4 shows a separate component 11, in which open into the chamber 8, three ducts 10 and three links 12. Each channel 10 or each connection 12 opens out on a different slope of the inner wall of the chamber 8 , so that the membrane 9 rests in three stages until the final stop on the inner wall.

Reference symbol list

1 - cylinder
2 - piston rod
3 - piston
4 - upper work area
5 - lower work area
6 - fastening device
7 - fastening device
8 - chamber
9 - membrane
10 - channel
11 - separate component
12 - connection
13 - throttle channels

Claims (5)

1. Hydraulic vibration damper for motor vehicles with a damping fluid containing cylinder, a sealed immersed immersed axially displaceably arranged piston rod and a piston attached to it, which divides the cylinder into two working spaces, the cylinder and the piston rod each having a fastening device for fastening of the body or on the wheel suspension, a chamber being provided in the area of the piston, which is divided by a membrane into two partial chambers and sealed against one another, one partial chamber via a channel with the upper working space and the second partial chamber with the lower working space is connected, characterized in that at least two channels ( 10 ) and at least two connections ( 12 ) are provided, which are each arranged on different pitch circle diameters, the inner surfaces of the chamber ( 8 ) having the orifices being different Angles run to the central axis. 2. Vibration damper according to claim 1, characterized in that the chamber ( 8 ) is arranged in the piston ( 3 ). 3. Vibration damper according to claim 1, characterized in that the chamber ( 8 ) is arranged in a separate component ( 11 ) axially below the piston ( 3 ) and attached to the piston rod ( 2 ). 4. Vibration damper according to claim 1, characterized in that the channels ( 10 ) and / or the connections ( 12 ) is designed as a throttle. 5. Vibration damper according to claim 1, characterized in that the cross section of the channels ( 10 ) and the United connections ( 12 ) are the same or different.