DE10024571A1 - Spring shock absorber system for wheel suspension or axles of motor vehicles has differential U-bellows with fluid-filled chamber connected to hydraulic accumulator - Google Patents

Abstract

The system incorporates tubular U-bellows, esp. differential U-bellows, with a chamber (5), which is filled with a fluid e.g. a water-alcohol solution, and communicates with a hydraulic accumulator (70) mounted on the chassis and/or the vehicle. The facing ends of two bellows parts (12,13) are connected via a connection sleeve (14) with working conduit (76). The fluid flow between chamber and hydraulic accumulator contains a throttle or at least two throttle back pressure valves (77).

Description

The invention relates to a combined spring-damper system for supporting wheel suspensions or axles on a drive Tool assembly with one between a wheel-bearing or a wheel guide connection and a vehicle body connection arranged hose bellows, which is between an outer bell and a rolling piston is arranged, wherein on the one hand the Au outer bell and the rolling piston each above the height of the ent speaking component at least partially varying Diameter of the walls contacting the hose bellows and on the other hand both ends of the hose bellows at the Ab rolling piston from sections of different diameters are sealingly attached, the lower attachment cut a larger diameter than the upper fastener section.

Such a pneumatic spring is known from US Pat. No. 4,518,154 known system for vehicles. The outer bell and the multi-part rolling pistons close a one-part diff renzrollbalg. Because of the low gas pressure and the  This construction requires the use of a differential roller bellows tion has an above average large volume.

Furthermore, from DE 29 70 2927 C1 is a spring damper system known that from a displacer without bellows, a Hydrospei cher and a hydraulic line connecting these parts stands. There is a mechanical throttle in the hydraulic line valve arranged. The displacer connects, like one hydropneumatic suspension system known the vehicle wheel suspension with the vehicle body. The system is with one filled hydraulic fluid. The latter is at Einfe a vehicle wheel through the throttle valve into a Hy dro storage displaced. The flow resistance of the throttle valve creates a damping force during compression of the gas volume in the hydraulic accumulator causes a resilient force. In the displacement principle presented here, a ver appears piston into a displacement cylinder. Both parts be due to friction in a guide and sealing joint against each other. The friction affects the response time of the Spring damper system so that when used in one Vehicle does not optimally roll off with this system supported wheels results.

The problem underlying the present invention is a to develop a combined spring-damper system that sets you up a low-friction displacer based on a tubular bellows in a slim design and with great transverse rigidity tet.  

The problem is solved with the features of the main claim. For this, a hose bellows is used, which is the difference roll bellows is formed, the bellows chamber with a fluid be is filled and with a chassis and / or vehicle side ge stored hydraulic accumulator communicates.

The type of displacement bellows, the type of connection to the chassis and on the vehicle body and filling the baig area with egg Fluid biased by a gas enables a sleek ken displacer without mechanical, frictional longitudinal guidance tion. A separate longitudinal guide is unnecessary because of the pressure in the displacement bellows, the strut moved relative to each other parts centered and stabilized over the two bellows menisci.

When the displacer is loaded or unloaded, flows between the displacer and the hydraulic accumulator over a cross section constriction in the form of a hydraulic line or a Breakthrough hydraulic fluid back and forth. The gestal direction of the line or breakthrough and the nature the throttling points arranged there influences the size and shape of the opening cross section the system damping. Here the respective throttling point can either be a nozzle or an orifice trained or at least be a throttle check valve. When using throttle check valves, the Lei tion or breakthrough cross section per flow direction each arranged at least one valve.

The gas cushion of the hydraulic accumulator essentially forms the Sy stem suspension.

By using a hose bellows in the form of a dif ferenzrollbalgs becomes the mechanical friction of the overall system essentially on the internal friction of the bellows and or mem reduced branch material. This shows the spring damper system  almost over the entire spring and damper rate range ideal response. The outer bell and / or the Ab Roller pistons can each directly over joints - even without one Interposition of rubber-elastic elements - while driving the vehicle body or attached to the chassis. That lowers u. a. the component weight, the manufacturing costs, the assembly effort and the maintenance costs.

Further details of the invention emerge from the Un claims and the following description of two clauses matically represented embodiments:

Fig. 1: spring damper system with a differential roller bellows and external hydraulic accumulator;

Fig. 2: spring-damper system with an integrated hydraulic accumulator.

Figs. 1 and 2 respectively show a combined spring-damper system comprising a displacer (10), a Hydrospei cher (70, 44, 62) and a FLÜS arranged between these sigkeitsführende working line (76) with an integrated throttle valve (77, 48 , 64 ).

The displacer ( 10 ) consists, among other things, of a multi-stage outer bell ( 30 ), a multi-stage rolling piston ( 50 ) and a multi-part differential roller bellows ( 11 ) connecting both parts. When compressing and rebounding, the rolling piston ( 50 ), for example attached to the chassis, moves up and down - centered by the differential roller bellows ( 11 ). The outer wall ( 23 , 24 ) of the differential roller bellows ( 11 ) rolls here on the outer bell ( 30 ) and on the rolling piston ( 50 ).

The outer bell ( 30 ) is a hollow body which here comprises at least partially cylindrical sections ( 31 , 33 ) which are connected to one another by means of a truncated cone-shaped transition piece ( 32 ). In Fig. 1, the sections ( 31 , 32 ) and the transition piece ( 33 ) are made from one part. The upper section ( 31 ) is closed at its upper end with a bottom ( 34 ). An adapter ( 35 ) for articulated connection to the vehicle body is molded onto the floor ( 34 ). The inner diameter of the upper, cylindrical section ( 31 ) is, for example, one third smaller than the inner diameter of the lower, cylindrical section ( 33 ).

The sections ( 31 ) and ( 33 ) can also have a frustoconical inner contour. In such a case, the upper section ( 31 ) would taper upwards and the lower section ( 33 ) would taper downwards.

The rolling piston ( 50 ) has an upper ( 51 ) and a lower section ( 55 ), both sections ( 51 , 55 ) having, for example, a cylindrical outer contour ( 56 , 57 ). The outer diameter of the upper section ( 51 ) is smaller than the outer diameter of the section ( 55 ). The outer diameter of the section ( 51 ) is, for example, approximately 60% of the inner diameter of the outer bell section ( 31 ). The diameter difference is chosen in the exemplary embodiment so that each of the gaps between the opposing sections ( 31 ) and ( 51 ) in the zones in which the menisci ( 21 , 22 ) of the differential roller bellows ( 11 ) move approximately the same are wide.

In Fig. 1, the lower portion ( 55 ) of the rolling piston tapers ( 50 ). The taper begins below the zone that can be contacted by the differential roller bellows ( 11 ). The lower end of the rolling piston ( 50 ) ends in an adapter ( 69 ) for articulated connection to the chassis ( 9 ).

The differential bellows ( 11 ) arranged between the rolling piston ( 50 ) and the outer bell ( 30 ) consists, among other things, of two possibly identical tubular bellows halves ( 12 , 13 ). The rolling bellows halves ( 12 , 13 ) are aligned coaxially to one another and are attached to one another in a gas-tight and liquid-tight manner via an approximately tubular connecting sleeve ( 14 ). The connecting sleeve ( 14 ) is a short tube, on each of which a roll bellows half ( 12 , 13 ) is pushed. The respective deferred section of the corresponding Rollbalghälf th ( 12 , 13 ) is on the connecting sleeve ( 14 ) with the help of a clamping ring ( 17 , 18 ) z. B. non-positively and positively fixed. In Figs. 1 and 2, the dung has Verbin sleeve between the clamping rings (17, 18) has a Rohrab section (15) which is not covered by the roll bellows halves (12, 13). This pipe section ( 15 ) has an outer diameter that is only slightly smaller than the inner diameter of the lower section ( 33 ) of the outer bell ( 30 ).

At Abrollkol ben for mounting the differential roll (11) (50) ben the lower end of which is open at the hose ends differential roll (11) with the inner wall (26) positioned scho on the upper end of the lower Abrollkolbenabschnitts (55) and by means of a clamping ring (59 ) clamped. From section ( 55 ) there has a radius reduced by the sum of the wall thicknesses of the clamping ring ( 58 ) and the bellows ( 11 ).

In a second step, the rolling piston ( 50 ) is pushed into the differential roller bellows ( 11 ) until the upper roller bellows reaches the middle of the upper section ( 51 ). During insertion, the lower region of the rolling bellows ( 11 ) slips over the clamping ring ( 59 ), so that the outer wall ( 24 ) of the bellows ( 11 ) bears against the rolling piston section ( 55 ).

In the middle of the upper section ( 51 ) there is a recess ( 53 ) in which the inner wall ( 25 ) from the upper end of the bellows ( 11 ) is fixed by means of a clamping ring ( 58 ). The depth of the recess ( 53 ) is selected so that the outer contour of the assembled clamping ring ( 58 ) has approximately the same diameter as the section ( 51 ) in the zone in which the outer wall ( 24 ) of the bellows ( 11 ) is on. Below the recess ( 53 ) in the embodiment examples, the section ( 51 ) has a diameter which is increased by approximately twice the bellows wall thickness compared to the diameter of the section ( 51 ) above the recess ( 53 ).

After attaching the differential rolling bellows ( 11 ) to the Abrollkol ben ( 50 ), both parts are inserted into the outer bell ( 30 ) until the connecting sleeve ( 14 ) with the rolling bellows half ( 12 ) bears against the transition piece ( 32 ). For final positioning of the differential roller bellows ( 11 ), the rolling piston ( 50 ) is now retracted into a central position within the outer bell ( 30 ). Here, the outer wall ( 23 ) of the roll bellows half ( 12 ) with formation of an upwardly oriented meniscus ( 21 ) over the clamping ring ( 58 ) and the outer wall ( 56 ) of the section ( 51 ).

As a result, the outer walls ( 23 , 24 ) of the differential roller bellows ( 11 ) roll on the outer walls ( 56 , 57 ) and the inner walls ( 36 , 37 ) with each operational relative movement between the parts ( 30 ) and ( 50 ). Since the menisci ( 21 , 22 ) of the differential roller bellows ( 11 ) move in narrow annular spaces with cylindrical walls in the execution examples, the centering forces and the lateral rigidity are almost constant over the entire stroke of the spring-damper strut.

The menisci ( 21 , 22 ) thus move in the entire stroke range between the rolling piston ( 50 ) and the outer bell ( 30 ) in, for example, cylindrical zones. Here, the Me niskus ( 21 ) realizes a piston area that is, for example, two thirds smaller than the effective piston area at the section ( 55 ).

The usable total stroke of the shock absorber corresponds to FIG. 1 approximately the inner diameter of the outer bell ( 30 ) in the region of the section ( 33 ).

The lengths of the individual roll bellows halves ( 12 ) or ( 13 ) correspond, for example, to one and a half to two times the bellows diameter in the region of section ( 33 ).

The space ( 5 ) enclosed by the differential roller bellows ( 11 ) is filled with an incompressible liquid ( 1 ) which, according to FIG. 1, is under pressure via a gas cushion enclosed in a hydraulic accumulator ( 70 ). The hydraulic accumulator ( 70 ) is designed for example as a bubble or membrane accumulator. The gas cushion ( 72 ) divided by the bladder or membrane ( 71 ) forms the suspension of the spring-damper system.

The hydraulic accumulator ( 70 ), which is shown only by way of example next to the outer bell ( 30 ), is connected via an operating line ( 76 ) to the bellows chamber ( 5 ). For this purpose, the working line ( 76 ) is led through the outer bell section ( 33 ) and connected to the connecting sleeve ( 14 ). The working line ( 76 ) itself thereby positions the connecting sleeve ( 14 ) in a form-fitting manner in the outer bell section ( 33 ).

In the housing ( 74 ) of the hydraulic accumulator ( 70 ) there are two opposing pressure stage valves in the form of spring plate valves ( 77 ) at the transition to the working line ( 76 ). One valve ( 77 ) opens in one flow direction. Here, the throttle effect of the individual throttle check valve ( 77 ) can be made adjustable by means of a controllable or regulable drive, if necessary.

A lockable supply line can optionally be connected to the working line ( 76 ). Via such a feed line, liquid would be supplied or removed from the displacer when used as an active spring damper system or as a level control. Additional forces can be realized in the desired manner by supplying and removing a certain amount of liquid. The absorption or removal of these additional quantities changes the damper and spring forces in the overall system.

The fluid ( 1 ) used in the spring damper system is, for example, a solution of water and alcohol. All alcohols are suitable for this solution, which can be mixed with water in any ratio at room temperature. For example, a water-ethanol solution or a water-glycol solution is used. A common water-glycol solution, as it is also used as a frost-protected coolant in internal combustion engines, has z. B. an ethylene glycol content of 33 to 50%. With the fifty percent solution, the spring damper system can be operated at temperatures as low as -35 ° Celsius. This solution also does not attack the usual elastomer materials. The rubber swelling is also on the order of magnitude of swelling in pure water.

Fig. 2 shows a spring-damper system with two space-saving integrated hydraulic accumulators. For this purpose, at least the lower portion ( 55 ) of the rolling piston ( 50 ) as a hollow body or stepped blind hole ( 61 ) with at least two separate cavities ( 62 ) and ( 65 ). For this purpose, the cavities are arranged coaxially to one another, for example.

The outer cavity ( 65 ) is an annular space, which is formed by the inner wall of the rolling piston ( 50 ) and a laminated hose membrane ( 66 ). The hose membrane ( 66 ) is fixed at the upper end by means of a ring adapter ( 67 ) in the region of the bottom of the blind hole ( 61 ) and with its lower end with a comparable ring adapter ( 67 ) in a screwed-in bottom in the rolling piston ( 50 ) . The annular space ( 65 ) is filled with gas via a seated valve ( 68 ) in this bottom.

The central cavity ( 62 ) is connected hydraulically via bores ( 63 ) and a double-acting spring plate valve ( 64 ) to the bellows chamber ( 5 ).

The second hydraulic accumulator is arranged in the area of the upper outer bell section ( 31 ). For this purpose, there is the outer bell ( 30 ) with a z. B. tubular housing ( 41 ) vice versa. Between this housing ( 41 ) and the outer contour of the outer bell ( 30 ) is an overall annular space, which is divided by a tubular membrane ( 42 ) into an inner ( 43 ) and outer annular space ( 44 ). The inner annular space ( 43 ) is filled with gas, cf. Valve ( 45 ), while the outer annular space ( 44 ), comparable to the fluid space ( 75 ) from FIG. 1, communicates with the bellows space ( 5 ) via at least one spring plate valve ( 48 ). The or the spring plate valves ( 48 ) sit in the embodiment of FIG. 2 in a Aufsatzge housing ( 46 ). The interior ( 47 ) of the housing ( 46 ) is connected to the bellows chamber ( 5 ) via the working line ( 76 ).

Possibly. the rooms ( 44 ) and ( 62 ) can also be directly connected hydraulically to one another and only communicate with the bellows chamber ( 5 ) via a double-acting spring plate valve.

In contrast to Fig. 1 is in the vented rear space ( 7 ) a rubber damper element ( 49 ) as an elastic impact. The upper section ( 51 ) of the Abrollkol ben ( 50 ) to reduce the unsprung mass is equipped with a closed bore ( 52 ).

The spring can be between the chassis and the vehicle body leg also with an outer bell hinged to the chassis be classified. To do this, at least the contours of the roll piston and the outer bell to the new orientation of the Aus spring direction can be adjusted.

As an alternative to the previously described embodiment, a spring damper system is conceivable in which the fluid ( 1 ) used in the system is a magnetorheological fluid. If, for example, a short ring-shaped section is now surrounded by a current-excited magnetic coil on the hydraulic working line ( 76 ), the excited magnetic coil in combination with the fluid ( 1 ) represents a variable throttle point. The flow rate increases with increasing current supply to the coil by an increase in the apparent or dynamic viscosity in the working line ( 76 ), which, among other things, allows the damping behavior of the overall system to be specifically changed.

Reference list

1

Fluid, water-glycol solution

5

Bellow space

7

Back room

9

landing gear

10th

Displacer

11

Hose bellows, differential bellows, bellows

12th

,

13

Bellows halves, bellows parts

14

Connecting sleeve

15

Pipe section

17th

,

18th

Tension rings

21

,

22

Menisci

23

,

24th

Outer walls

25th

,

26

Inner walls

30th

Outer bell

31

upper section

32

Transition piece

33

lower section

34

ground

35

adapter

36

,

37

Interior walls

41

Housing, tubular

42

Membrane, tubular

43

inner annulus

44

outer annulus

45

Valve

46

Attachment housing

47

Housing interior

48

Spring plate valve

49

Rubber damper element

50

Rolling piston

51

upper section

52

drilling

53

Screwing

55

lower section

56

,

57

Exterior walls

58

,

59

Tension rings

61

Blind hole

62

inner cavity, central

63

Holes

64

Spring plate valve

65

outer cavity, annulus

66

Hose membrane

67

Ring adapter

68

Valve

69

Adapter, adapter with swivel joint

70

Hydraulic accumulator

71

membrane

72

Gas cushion

74

casing

75

Fluid space

76

Work management

77

Throttle valves, compression valve

Claims (9)

1.Combined spring-damper system for supporting wheel suspensions or axles on a vehicle body with a hose bellows arranged between a wheel-bearing or wheel-guiding connection and a vehicle body-side connection, which is arranged between an outer bell and a rolling piston, the first being the outer bell and the From the rolling piston each has at least regionally varying diameters of the walls contacting the hose bellows over the height of the corresponding component and, on the other hand, both ends of the hose bellows are sealingly fastened to the rolling piston on sections of different diameters, the lower fastening section having a larger diameter than the upper fastening section , characterized by
that the bellows chamber ( 5 ) is filled with a fluid ( 1 ) and communicates with a chassis and / or vehicle-mounted hydraulic accumulator ( 70 , 44 , 62 ). 2. Combined spring-damper system according to claim 1, characterized in that the Schlauchrollba1 g is an at least two-part differential roller bellows ( 11 ). 3. Combined spring-damper system according to claim 1, characterized in that the two mutually facing ends of the two bellows parts ( 12 , 13 ) of the mounted differential rolling bellows ( 11 ) via a connecting sleeve ( 14 ) are connected to each other. 4. Combined spring-damper system according to claim 1, characterized in that the connecting sleeve ( 14 ) has an outer bell ( 30 ) crossing the working line ( 76 ). 5. Combined spring-damper system according to claim 1, characterized in that the hydraulic accumulator ( 70 , 44 , 62 ) is a membrane or bladder accumulator. 6. Combined spring-damper system according to claim 1, characterized in that in the fluid flow between the bellows chamber ( 5 ) and the hydraulic accumulator ( 70 , 44 , 62 ) at least one throttle position or at least two throttle check valves ( 77 , 48 , 64 ) are arranged. 7. Combined spring-damper system according to claim 1, characterized in that the respective throttle check valve ( 77 , 48 , 64 ) is a compression valve. 8. Combined spring-damper system according to claim 1, characterized in that the fluid ( 1 ) is a water-alcohol solution. 9. Combined spring-damper system according to claim 1, characterized in that the bellows chamber ( 5 ) is connected via a feed line in driving operation to implement an active spring-damper system with an external fluid supply.