DE102015011376A1 - Air suspension and suspension system for suspensions - Google Patents

Abstract

The innovation describes an air-spring damper system in which coupling by valve technology of several of the air suspension spring counteracting air chambers, the spring characteristic for achieving a damping hysteresis or a modified static spring characteristic can be influenced.

Description

Summary:

The innovation describes an air-spring damper system in which by coupling via valve technology ( 1.9 . 2 . 3 and 5 ) of several of the air spring ( 1.1 ) counteracting air chambers ( 1.2 . 1.3 ) the spring characteristic can be influenced to achieve a damping hysteresis or an altered static spring characteristic.

State of the art:

In the mountain bike field forks and rear suspension are now widely used and mandatory for special types. But not only the feathers are the focus. Extensive adjustments of the spring rate and damping of rebound and rebound are required by the customer. Weight also plays an important role in a modern mountain bike. In the high end range, every gram of weight saved counts. There is a great potential in saving components by integrating the damping into the air spring. In the case of a telescopic fork, the air spring is traditionally located in one of the two standpipes and an oil damping system in the other standpipe. The air system usually consists of two separate air chambers or air springs, the positive chamber includes the air spring whose characteristic is the suspension spring for strong deflections. The so-called. Negative chamber includes the opposite of this spring acting negative air spring whose volume is springy small, expands during compression and thus increases. The positive chamber, however, is spring-down large and is compressed during compression. The output pressure of both springs determines with the effective areas of the respective chamber the resulting air characteristic of the entire system. Since it comes with bicycles due to the typical off-road use as well as the mass ratio vehicle-driver often full rebound, a characteristic is desirable, the beginning of which is as possible in the origin of the force-displacement diagram: Thus, even with small shocks in the rebounded state ensures effective function. A hard impact in the end stop of the spring unit is avoided by this characteristic beginning in the origin. Finally, the course of the spring characteristic can also be influenced by the volume ratio of the positive and negative chambers: a negative chamber which is large relative to the main chamber linearizes the entire characteristic curve, while a small negative chamber produces a pronounced S-shaped profile. Usually, this air spring is complemented by a parallel arranged hydraulic damping unit. This unit can be omitted if the volume of the main and negative chambers are made variable via certain valve systems. The state of the art is already mapped by various manufacturers.

BMW has teamed with Continental Automotiv Systems to develop a rear strut for the HP2 Enduro motorcycle. In this system, the air takes over the task of suspension and damping. This results in a weight advantage over conventional struts with coil spring and oil damping. The throttling of the air is realized by plate valves in the positive chamber. This will dynamically, d. H. depending on the compression speed and amplitude, the spring characteristic over the stroke in the direction of rebound and rebound changed, it creates a hysteresis, which generates a vibration damping.

An air damping system has also been developed in the bicycle sector. Cane Creek has launched several suspension struts for rear bicycle bodies, currently using the model called Cloud Nine. The spring base is determined by air pressure with the aid of a pump, the rebound and compression stages are separately adjustable by means of adjusting valves. Just like the BMW Air Damping System, the damping of the rebound and compression stages takes place via two positive chambers.

Explanation of terms of suspension technology:

• Bodywork:

• Low frequency vibrations of the vehicle body (sprung mass vehicle and driver).

• traction:

• From the wheel at ground contact transferable force. The traction increases with increasing ground contact force.

• Attenuation:

• Influencing the dynamic spring characteristic by dissipation. Hysteresis of the spring characteristic between spring and rebound.

• rebound damping:

• Damping the rebound movement. Rebound damping reduces build-up, but also traction by reducing ground contact force during rebound.

• Compression damping:

• Damping of the compression movement. The compression damping counteracts a lifting of the wheel when driving over an obstacle by reducing the kinetic energy of the accelerated unsprung masses. However, the compression damping also increases the body movement. Due to the increased wheel load fluctuations, the traction is reduced. On the bicycle, compression damping can be used to reduce pedaling induced body vibrations, but this degrades the responsiveness of the suspension.

• positive chamber:

• Volume of the mainspring causing the rebound movement.

• Negative chamber:

• Volume of the main air spring to optimize the spring characteristic counteracting negative spring.

• Say:

• From the weight of the driver and vehicle resulting static compression travel. The sag should be about 20% of the total spring travel.

• Nick compensation:

• Partial compensation of pitching movements of the vehicle body when braking / accelerating or uphill / downhill by static influence of the spring characteristic.

• Lock out:

• Blocking of the spring-damping unit to body movement z. B. in the saddle or sprint to avoid.

Problem description Pneumatic spring damping system for single-track vehicles according to the prior art (positive-chamber-side damping):

With positive-chamber-side damping, the positive chamber is made in two parts, both chambers are coupled together via valve technology. One of the two positive chambers forms the cylinder which takes over the piston guide. At 20% sag, this volume is thus at least piston area · travel · 80%. This volume acts as a spring connected in series with the damper. Thus, a strong and well responding damping is possible only at lower deflection. Constellation changes in the area of Sag are the result.

Theoretically optimal suspension damper (distance- and frequency-dependent):

A chassis damper should fundamentally effectively dampen low-frequency build-up in the area of the sag (strong damping at the beginning of the spring travel with low on-rebound frequency), but nevertheless ensure optimum ground contact even after major road bumps (less damping with increasing travel and / or higher rebound frequency).

In the bicycle sector, a compression damping in the area of Sag makes sense in order to reduce cadence-induced build-up vibrations. A compression damping over the entire travel is not needed due to the low unsprung masses and the steep spring characteristics and low speeds in normal mountain bikes (except downhill bikes).

Object of the invention:

In contrast to the research products which dampen the positive chamber side, the innovation realizes an influence of the spring characteristic on the negative chamber side via the pressure compensation of two negative chambers ( 1.2 . 1.3 ) for the purpose of damping and, if necessary, to achieve a pitch compensation and / or a lock out.

Solution according to the invention:

In the case of negative chamber-side influencing of the spring characteristic, one of the two negative chambers, which are coupled to one another by means of valve technology, sets the volume between the dividing wall which arises during compression (increasing). 1.8 ) and pistons ( 1.7 ) within the cylinder forming the piston guide ( 1.4 At 20% Sag, this volume is only piston area × travel × 20%. With this small volume ( 1.2 ), in contrast to the prior art (positive-chamber-side damping) a strong and well-responsive damping already in the field of Sag possible. Although the hysteresis which can be generated is smaller in the case of a negative-chamber-side influencing of the spring characteristic than in the design according to the prior art (positive-chamber-side influencing of the spring characteristic), it is more decisive than the magnitude of the hysteresis that small hubs already produce significant hysteresis, ie damping.

In a design of the valve technology ( 1.9 ) with throttling in tension and compression (examples: 2 . 5 ) the attenuation becomes frequency dependent.

The path and frequency dependence thus corresponds qualitatively to the theoretically optimal suspension damper.

Frequency dependence: After a quick compression movement, less air is released from the chamber 1.3 in the chamber 1.2 flowed as after a slow compression movement of the same amplitude.

The rebound damping is thus stronger at low-frequency vibrations, as in the rebound movement a larger amount of air throttled by chamber 1.2 in chamber 1.3 flows as high-frequency oscillations.

If a particularly strong damping z. As is required in Hinterradfederungen with highly translated damper, the negative-chamber-side damping tends to vibrate, since at almost closed rebound throttle valve "air cushion" is created. This means: The rebound throttle valve can only be closed to the extent that the dissipation by staying too large an amount of air in the chamber 1.2 again reduced. Remedy here creates a valve technology as in 5 Drawn: When there is a strong increase in pressure on the rebound throttle valve ( 5.1 ) opens the rebound damping valve ( 5.2 ) and the air can via a second rebound throttle valve ( 5.3 ) in the chamber 1.3 escape. This allows the rebound throttle valve ( 5.1 ) are closed, without a too large "air cushion" in chamber ( 1.2 ) arises.

With the innovation can also be a lock out, ie a block implementation, in which the two negative chambers ( 1.2 . 1.3 ) decoupled in the rebound state. As a result, the positive chamber ( 1.1 ) on the piston ( 1.7 ) no force, the resulting characteristic ( 4.1 ) begins now depending on the design of the volumes at a force that is far above the static force with stationary suspension. This mode is desired when in sporty use of a bicycle chassis variations, eg. B. in sprint, are not desirable.

Following the same principle as with a lock out, a pitch compensation can be realized with the innovation. Here, the two negative chambers ( 1.2 . 1.3 ) but not completely disconnected from each other, but it is sufficient via a pressure valves ( 2.1 . 2.4 . 5.2 . 5.7 ) statically held differential pressure between the chambers ( 1.2 . 1.3 ).

The system described can be combined with a positive-chamber-side damping according to the prior art, whereby in addition a greater hysteresis can be generated towards the end of the spring travel. This combination is advantageous when certain uses such as downhill and depending on the vehicle type larger unsprung masses are available.

Resulting spring characteristics:

In order to clarify the effect of a negative chamber-side influencing of the spring characteristic, are in 4 The resulting spring characteristics are shown using the example of a suspension fork with a stroke of 100 mm:
( 4.1 ) shows the characteristic curve in the case of a negative chamber which is decoupled in the zero position via valve technology ( 1.3 ).
( 4.2 ) shows the characteristic curve when the negative chamber is coupled in the zero position ( 1.3 ).
( 4.3 ) shows the characteristic in the case of a valve chamber disconnected at 20 mm stroke negative chamber ( 1.3 ).
( 4.4 ) shows the characteristic in the return stroke with a negative chamber decoupled at 80 mm stroke ( 1.3 )

1 shows the overall system as a block diagram with negative-chamber-side and positive-chamber-side influencing the spring characteristic.

2 shows valve technology for the static and dynamic influence of the spring characteristic. All valves can be made adjustable.

3 shows valve technology for directional damping.

4 shows negative-chamber-side influenced spring characteristics.

5 shows valve technology to enhance the negative chamber side train and compression damping. All throttles and pressure valves can be made adjustable.

LIST OF REFERENCE NUMBERS

1.1.1

Positive chamber 1

1.1.2

Positive chamber 2

1.2

Negative chamber 1

1.3

Negative chamber 2

1.4

cylinder

1.5

Partition positive chamber

1.6

Valve technology for positive chamber-side influencing of the spring characteristic

1.7

Piston with piston rod

1.8

Partition Negative chamber

1.9

Valve technology for negative-chamber-side influencing of the spring characteristic

2.1

Pressure valve for the static influence of the spring characteristic in the rebound direction (can be used as an adjustable-pitch valve in the case of an adjustable design)

2.2

Throttling valve for dynamically influencing the spring characteristic in rebound direction (rebound damping)

2.3

Throttling valve for dynamically influencing the spring characteristic in springing direction (compression damping)

2.4

Pressure valve for the static influence of the spring characteristic in the spring-loaded direction (in the case of an adjustable design, it can be used as pitch compensation valve and / or lock-out valve)

3.1

check valve

3.2

Throttle valve (can be made adjustable)

4.1

Characteristic curve for negative chamber uncoupled in the zero position via valve technology ( 1.3 ).

4.2

Characteristic curve with a negative chamber coupled in the zero position ( 1.3 ).

4.3

Characteristic curve for negative chamber decoupled via valve technology at 20 mm stroke ( 1.3 ).

4.4

Characteristic in the return stroke with a negative chamber decoupled at 80 mm stroke ( 1.3 ).

5.1

Throttle valve 1 rebound

5.2

Pressure valve rebound

5.3

Throttle valve 2 rebound

5.4

Check valve Rebound

5.5

Check valve pressure stage

5.6

Throttle valve 2 pressure stage

5.7

Pressure valve pressure stage

5.8

Throttle valve 1 pressure stage

Claims (13)

Pneumatic spring and / or damping system, characterized in that the negative chamber in at least two by valve technology ( 1.9 ) coupled chambers ( 1.2 . 1.3 ) to affect the spring characteristic statically and or dynamically. Pneumatic spring and / or damping system according to claim 1, characterized in that by at least one series circuit ( 2 ) of a throttle valve ( 2.2 ) with a pressure valve ( 2.1 ) the dynamic and the static spring characteristic can be influenced. Pneumatic spring and / or damping system according to claim 1, characterized in that with at least one pressure valve, the static spring characteristic can be influenced. Pneumatic spring and / or damping system according to claim 1, characterized in that with at least one throttle valve, the dynamic spring characteristic can be influenced. Pneumatic spring and / or damping system according to claim 1 to 4, characterized in that at least one valve is designed to be adjustable. Pneumatic spring and / or damping system according to claim 5, characterized in that the dynamic and / or the static spring characteristic is adjustable for the user. Pneumatic spring and / or damping system according to claim 5, characterized in that the dynamic and / or the static spring characteristic can be dynamically controlled to actively adapt the chassis to different driving situations. Pneumatic spring and / or damping system according to claim 1, 2, 3, 5, 6 and 7, characterized in that with at least one actively controlled pressure valve, the static spring characteristic for realizing a pitch compensation can be influenced in Einspurfahrzeugen. Pneumatic spring and / or damping system according to claim 1, 2, 3, 5, 6 and 7, characterized in that with an adjustable pressure valve or with a switchable check valve, the static spring characteristic for the realization of a lockout can be influenced. Pneumatic spring and / or damping system according to claim 1, 2, 4, 5, 6, 7 and 8, characterized in that with at least one actively controlled throttle valve, the dynamic spring characteristic for realizing an active damping adjustment can be influenced in Einspurfahrzeugen. Pneumatic spring and / or damping system according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, characterized in that with a non-return valve ( 3.1 ) and a parallel-connected throttle valve ( 3.2 ) the dynamic spring characteristic can be influenced in rebound direction (rebound damping). Pneumatic spring and / or damping system according to claim 1, characterized in that a multipart positive chamber, consisting of at least two separate chambers ( 1.1.1 . 1.1.2 ), connected by a valve system ( 1.6 ) is combined for positive chamber-side influencing the spring characteristic with a system for negative chamber-side influencing the spring characteristic. Pneumatic spring and / or damping system according to claim 1, 2, 4, 5, 6, 7, 10 and 11 characterized in that the maximum possible rebound in the rebound dissipation with a second throttle valve ( 5.3 ) can be increased. The second throttle valve ( 5.3 ) from the pressure valve ( 5.2 ) released after the first throttle valve ( 5.1 ) the opening pressure of the pressure valve ( 5.2 ) has been exceeded.

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