DE202004015535U1 - Motor vehicle has spring damper combination for the tailgate comprises elastic spring and two chamber fluid damper with piston and throttle between chambers - Google Patents

Abstract

A vehicle body with a hinged flap comprises an elastic spring (4) support for the flap movement and a fluid damper (6) with cylinder and piston (16) and two separate chambers (24,26), one sealed and the other with a fluid connection and with a throttle between them. An independent claim is also included for an elastically sprung component for the above.

Description

The The present invention relates to a vehicle having a body, one over at least one hinge connected to it, swiveling opening flap and a spring made of elastic spring material arranged in this way is that it's the movement of the opening flap supported.

Such spring systems for opening flaps and in particular tailgates of motor vehicles are, for example, from DE 196 43 604 A1 and DE 195 04 961 A1 known. The problem with such spring systems, which only have conventional springs made of elastic spring material, lies in the dynamic opening behavior that can be achieved thereby and in their complex construction. The relatively complex construction is particularly the case with helical compression springs, since these have to be guided, for example, through an internal guide and prevented from buckling. The conventional springs made of spring material also release the stored energy relatively suddenly, so that the opening flap is accelerated very strongly and finally hits the stop with great force. In order to alleviate this problem, it has been proposed to use gas pressure springs alone or in combination with conventional springs made of elastic spring material, as is the case, for example, in DE 296 22 242 U1 . DE 196 46 939 C2 and DE 101 44 791 A1 is described. The relatively good damping properties of the gas pressure spring are used in the overall system. The combination of conventional spring and gas pressure spring is also advantageous for other reasons; a gas pressure spring can develop relatively high spring forces with a relatively small installation space. This is offset by the disadvantage of the gas pressure spring that the spring force is very temperature-dependent. In the literature, values of over 3% change in spring force with a 10 ° temperature change are given. In practice, this means that the spring force of gas pressure springs does not sufficiently support the opening movement at very low temperatures, while at very high temperatures the spring force supplied by the gas pressure spring is too high and causes the opening flap to open uncomfortably quickly. The combination of conventional spring and gas pressure spring makes it possible to compensate the temperature dependency of the gas pressure spring considerably, but not to switch it off completely. In addition, due to the manufacturing process, both the gas pressure spring and a conventional spring have certain spring tolerance ranges, so that the tolerances of the spring types combine in such a spring combination. This makes it difficult to connect the opening flap of a vehicle in such a way that it requires a defined, predetermined opening force over its opening path. In particular with the increasing use of drive motors for opening such opening flaps, it is of great practical importance to have an opening force that is essentially constant and fixed over the movement path, regardless of the ambient temperature.

The The present invention is therefore based on the object of the spring system for one Vehicle opening flap to be interpreted so that the disadvantages of conventional springs elastic spring material and the disadvantages of gas pressure springs eliminated are and that it is independent provides a given opening characteristic of the working temperature.

According to the invention Task solved by that a fluid damper to dampen the Movement of the opening flap is provided, the fluid damper is designed as a cylinder-piston unit and the cylinder-piston unit as one open system preferably with two separated by the piston Chambers and a throttle passage formed between the chambers is. A chamber is closed against the environment and the second chamber is in fluid communication with the environment. The fluid damper can be much smaller compared to a gas spring Be great. It is also possible the fluid damper operate with ambient pressure, so that a complex seal of the fluid damper, like that is required for a gas pressure spring is not required. Moreover fluid dampers working with ambient pressure are temperature independent.

Preferably are spring and fluid damper too combined into one unit. The combination can be produce a particularly compact component.

The The invention further relates to a unit made of elastic spring Spring material and fluid damper to support of vehicle opening flaps. The assembly can have one end, for example, at one end be attached to the body side and their other End at the opening flap be connected. It is also possible with certain hinges the assembly or the spring and / or the fluid damper To have components of the hinge connected. As examples for such Hinges are called four-hinge hinges or hinge hinges.

It is possible to design the throttle passage in such a way that it only allows flow through a certain section of the movement path of the piston in the cylinder, for example by inlet into the piston at the piston head or at the front of the piston, while the outlet from the throttle passage laterally through the piston skirt takes place in a channel in the cylinder wall, which is formed only in the predetermined desired section of the movement path. The damping characteristics can thus be specifically adapted to the respective needs by providing several different throttle passages. Alternatively or additionally, in addition to the actual "main piston" with such a throttle passage, a plurality of additional pistons can also be provided with throttle passages, each of which is slidably mounted on the piston rod up to a stop. At the beginning of the movement path, the main piston can act first, while the secondary piston (s) are slidably mounted on the piston rod. Only when a secondary piston engages with a corresponding stop on the piston rod is this also moved, and the flow of the fluid through the further throttle passage additionally influences the damping behavior.

Preferably is a one-way flow passage provided parallel to the throttle passage, which is formed in this way is that a substantially unthrottled flow in a direction of movement of the opening door of fluid from one chamber to the other chamber is. In some applications, it is desirable to have the damping characteristic only in one direction and with opening upwards Flaps typically in the opening direction the opening flap to have. Typically one is required in the closing direction closing force increasing Damping is often undesirable. To a one-way flow passage can be provided for this purpose, which allows the fluid to flow in one direction of movement, so that the fluid can flow essentially around the throttle passage. Such a one-way flow passage can be a simple flow passage be provided in which a valve device or a flutter valve is a stream allowed in one direction only. Exemplary for such a valve device is a spring biased elastically in the closing direction Valve element, for example a ball, by the spring in one Valve seat is pressed. Such a valve device blocks the path of the fluid in one direction and allows the fluid to flow Fluids in the opposite direction by removing the ball from the Valve seat shifted away against the force of the spring. Basically can the throttle passage and / or the one-way flow passage in the piston the cylinder-piston unit can be provided. However, it is also possible to do this Passages differently, for example outside of the cylinder the cylinder wall or through a flow depression in the cylinder wall, from one chamber to the other chamber.

The Cylinder-piston unit as an open system with one through the Piston sealed against the environment chamber and a throttle passage formed between chamber and environment. Such a system can very simple by definition be constructed. The fluid used therein is then typically the ambient air. Such a system has only a closed one Chamber, the second chamber communicates with the environment. On this way there are pressure differences in the chamber and the environment for example through change the outside temperature compensated. Such an open system works independently of temperature.

at the open system there is a low risk that in particular at very low temperatures the water vapor in the air fluid damper freezes. In particular, there is a risk of the throttle passage freezing. To avoid excessive restriction of the throttle passage when freezing functionality to have it cheap be an additional pressure relief valve to provide, for example in the manner of a flap valve or a spring loaded ball as described above. This Valve can be designed so that it opens at a certain predetermined pressure value that is above the usual resistance provided by the throttle passage.

A drive motor is preferably provided for moving the opening flap. An important reason for determining the opening characteristics of an opening flap as precisely as possible via the movement path is the increasing desire to use drive motors to drive such opening flaps. An attempt is generally made to make the drive motors as small as possible, which is possible in principle if the movement characteristics of the opening flap are such that the weight of the opening flap is essentially always balanced by the spring system or the opening flap has a slight tendency to move in the opening direction. In the case of the temperature-dependent gas pressure springs or gas dampers, such a temperature-independent opening characteristic is practically not feasible. The drive motors for opening flaps with spring systems of this type must be correspondingly large. In addition, safety systems for opening flaps driven in this way must be provided in order to prevent crushing of body parts. A system in which the opening characteristic varies as a function of temperature inherently has the problem that the safety shutdown threshold value must also be specified as a function of temperature, so that the drive motor must be controlled according to a specific temperature characteristic. Such a complicated control can be avoided by using the spring system itself has a temperature-independent opening characteristic. Electric motors, hydraulic drives, etc. can be used as drives, for example.

Preferably is the fluid damper arranged inside the coil spring. It typically says there sufficient space available, around such a fluid damper to position without additional Space required. The Fastenings for fastening the assembly to the vehicle integrally with the cylinder or the piston rod of a cylinder-piston unit be connected and the fastenings on the cylinder or the piston rod or the attacks for the Spring ends should be formed.

Preferably serves the fluid damper as a telescopic guide for the Coil spring. For example, the outer surface of the cylinder may be slightly smaller Have diameters as the inside diameter of the coil spring, so that the inside of the turn comes into contact with the cylinder can. This prevents the spring from buckling. In addition can the unit to the outside through a housing to be introverted. You can For example, two sleeves that telescopically slide into each other casing define, being between the sleeves a seal can be provided to prevent dirt from entering and prevents moisture inside. It can be cheap the inner sleeve, i.e. the sleeve with the smaller diameter in the area of the piston rod and the inside diameter of this sleeve slight larger than the outside diameter form the coil spring, so that this sleeve forms an outer guide for the coil spring. In this way, the spring is reliably guided over the entire length of the spring.

Preferably the spring is arranged inside the fluid damper. To this Way, the outer sleeve of the Cylinder-piston combination include the spring. The Spring supports then preferably on the piston or a movable with the piston Part and at its opposite end to a stop that relative to the cylinder sleeve is essentially set down.

Preferably a device for adjusting the spring preload is provided. With such a device, on the one hand, the manufacturing-related Compensate the tolerance of the spring so that the opening characteristic of the spring tolerance is free can be set. On the other hand, it is possible to create a customer-specific one certain opening characteristics manufacture.

Preferably a device for adjusting the damping properties is provided.

Preferably, a cold-formed wire spring with a high volume utilization value is used as the conventional spring, which consists of a steel wire with a diameter of at least 1 mm and a composition of 0.5 to 0.9 percent by weight carbon, 1.0 to 2.5 percent by weight silicon, 0.3 up to 1.5 percent by weight of manganese, 0.5 to 1.5 percent by weight of chromium and, moreover, with proportions of other elements and the rest iron and immanent additions. The steel wire is a drawn steel wire, patented according to DIN 17014 and shaped by 60 to 80%, which is martensitic hardened and has a tensile strength of more than 2300 N / mm ² and a fracture necking of more than 40%, which then cold-formed to the desired spring, secondary hardened and annealed at 200 to 400 ° C. The spring can be shot peened to increase its durability. The spring wire can be frozen in an intermediate phase prior to the manufacture of the spring and can contain 0.05 to 0.3 percent by weight of vanadium and a total amount of 0.05 to 0.3 percent by weight of vanadium, niobium and / or tantalum.

The Invention and refinements of the invention are described below of illustrated embodiments. It demonstrate:

1 a unit with springs and fluid damper, partly in section for a vehicle according to the present invention;

2 a detailed view of the assembly;

3 a detailed view of an alternative embodiment of the assembly;

4 a detailed view of the seals of the damper in the assembly;

5 a detailed view of a unit; and

6 an alternative embodiment of the assembly according to the present invention.

1 shows an assembly 2 , having a spring 4 and a fluid damper 6 , The feather 4 is a conventional spring made of resilient spring material and is a helical compression spring in the embodiment shown. It is also possible to use the fluid damper 6 to combine with other springs, such as spiral springs. Such combinations can also be used as a structural unit 2 be executed, or it can be the spring 4 made of elastic spring material basically separate from the damper fer 6 be arranged on the opening flap. It is also possible to replace the helical compression spring 4 to use a coil tension spring when a reverse loading direction is desired, for example with opening flaps opening downwards and / or when they are used in connection with deflection mechanisms such as lever arrangements or cables or cable deflections.

It can also be seen that the structural unit 2 a connection head at each of its ends 8th . 10 having. The unit 2 the embodiment shown is also essentially sealed from the outside. For this purpose, sleeves are arranged telescopically one inside the other 12 and 14 intended. The sleeve 12 has an inside diameter that is essentially the outside diameter of the coil spring 4 equivalent. The sleeve 14 has an inner diameter that is essentially the outer diameter of the sleeve 12 equivalent. The pods 12 and 14 are preferably made of an aluminum material. For example, they can be produced inexpensively using suitable drawing tools. They can also be made of plastic material.

The fluid damper 6 is as a cylinder-piston unit 16 educated. fluid damper 6 based on the principle of a cylinder-piston unit 16 are formed, in particular with coil springs 4 combine particularly cheap and are therefore particularly suitable for the unit 2 of the embodiment. The cylinder-piston unit has a cylinder 18 , a piston shown in quarter section 20 and a piston rod 22 on. In the area in front of the piston 20 is a first chamber 24 , and there is a second chamber around the piston rod 26 educated. 2 shows the cylinder piston unit in more detail 16 inside the spring 4 , The outer sleeve can also be seen more clearly 14 and the inner sleeve 12 in the area of the piston rod 22 , It can also be seen that the inner sleeve 12 at its front end with a phase 28 is trained, which ensures that the spring 4 when compressing the assembly 2 trouble-free inside the inner sleeve 12 can be inserted.

The cylinder 18 is also essentially formed by a tubular sleeve. This tube is also preferably made of an aluminum material. For this purpose too, the accuracies achievable with drawing tools are sufficient, so that there is also a tube for the cylinder 18 can be produced very inexpensively.

The piston rod is at its front end 30 tapered, and on this tapered end is the piston 20 attached. The piston 20 essentially has an outer diameter that is the inner diameter of the cylinder 18 equivalent. In addition there is a seal 32 for example in the form of an O-ring seal between the piston and cylinder in a sealing groove of the piston 20 provided inlaid. Through the piston 20 there is a throttle passage 34 educated. It can be seen in particular that the throttle passage 34 a very small cross-section compared to that of the throttle passage 34 leading flow passages 36 . 38 , Has. In principle, the throttle passage 34 be arbitrarily short, and it is preferred for manufacturing reasons, the throttle passage 34 with the thin cross section not over the entire length of the piston 20 train. In terms of manufacturing technology, it is much simpler, relatively large flow passages 36 . 38 For example, by drilling or integrally in the injection molding process and only the remaining throttle passage over a short, short intermediate area 34 with the reduced cross section. It is advantageous to provide a device that prevents dirt and liquid from entering the throttle passage 34 arrives. This can be done by appropriate devices such as filters, etc. at the inflow openings in the flow passage 36 . 38 happen.

The piston 20 can be made of plastic material, for example. It is possible to use the piston 20 made of plastic in the injection molding process, the flow passages 36 . 38 , the groove for the o-ring 32 , etc. can be produced at the same time. It may be necessary to subsequently manufacture the throttle passage with the relatively small cross section by drilling or to rework it to the desired size.

How to get in 2 can also recognize the feather 4 an inner diameter that is slightly larger than the outer diameter of the cylinder or the tube of the cylinder 18 , The cylinder-piston unit thus serves 16 as an internal guide for the spring 4 , As already mentioned, the inner sleeve is in the area of the piston rod 12 provided as an external guide. As a result, and especially when the additional outer guide through the sleeve 12 is present, the spring can be guided reliably and safely 4 realize with very little space and little additional manufacturing effort. In particular, it ensures that the spring 4 cannot buckle to the side. To ensure the most stable guidance possible, the piston has 20 according to the embodiment a substantial length. It is convenient if the piston 20 is at least as long as its diameter is. The length of the piston is preferably 1.5 to 5 times the piston diameter and preferably approximately 2 to 3 times the piston diameter.

From the chambers 24 and 26 one is sealed off from the environment and the other in fluid communication with the environment ("open system"). If an open system is used with a tailgate opening upwards, you typically become the chamber 26 , which is arranged on the side of the piston rod, form as the sealed chamber while the chamber 24 is open to the environment.

In 3 is a quarter section through the unit 2 shown. This quarter cut shows one of the two sleeves 12 respectively. 14 in the view from the outside. The piston is shown cut 20 shown. You can see the groove for the sealing ring 32 as well as a flow passage 36 , at one end a throttle passage 34 is trained. The throttle passage 34 the 3 has a so-called flutter valve 64 on. The flutter valve essentially consists of one against a stop 66 supported valve spring 68 and a bullet 70 by the valve spring 68 against a valve seat 72 is held with bias. By specifying the spring force of the valve spring 68 the damping of the assembly can be adjusted very precisely. The greater the spring force of the valve spring 68 the greater the damping. The spring force can be achieved, for example, by using different valve springs or by moving the stop 66 cause. So it is possible, for example, the element that stops 66 carries, with an external thread and a corresponding thread in the piston 20 to screw. In this way, the valve spring preload can be easily varied. In open systems in particular, it is thus possible to adjust the stop by means of a corresponding access opening with a tool, for example a screwdriver, and thus to adjust the damping properties to suit the customer.

Instead of this ball seat valve 64 Another unidirectional valve can also be provided which opens or closes a throttle passage, for example a simple sealing plate which is biased against a seat by spring-elastic force and which is lifted off the seat by the fluid flow and thus allows flow. In this embodiment too, a device for adjusting the damping properties can be provided in a simple manner. For example, it is possible to provide an adjustable stop which can be displaced along the spring-elastic preloaded sealing plate from its clamping point in the direction of its free end. The further this stop is moved towards the free end of the sealing plate, the higher the spring force and the harder the damping.

Will the piston 20 the 3 in the view of the 3 Moved to the left, the fluid builds out of the chamber 26 a pressure on the bullet that is sufficient 70 from the valve seat 72 lift off, and then the fluid can exit the chamber 26 into the chamber 24 stream. Then the piston 20 in the opposite direction, ie to the right in the view of the 3 , moves, the fluid can flow back into the chamber 26 either through the inherent leaks in the system, ie between pistons 20 and cylinder wall and on the sealing ring 32 past. Alternatively, a return flow passage, for example in the form of a one-way flow passage, can be provided. Such a one-way flow passage can basically be constructed like the throttle passage 34 the 3 , Through different dimensioning of the throttle passage 34 or the one-way flow passage and by different spring preloading of the valve elements, different damping effects can be provided in the two directions.

In 4 is the piston end of the assembly 2 shown. In particular, you can see that in the cylinder again 18 guided pistons 20 which is similar to the representation of the 1 is shown, ie the one in the 4 the upper half of the piston shown is uncut, while the lower half of the piston is shown cut. One can see that the chamber 26 to the left of a guide 40 completed, which in turn with an O-ring 42 against the piston rod 22 is sealed. The leadership 40 can also be made of plastic material in the die casting process. The leadership 40 has circumferential grooves 44 . 46 on, in the embodiment shown the tube of the cylinder 18 is crimped. In this way there is a secure connection between the tube of the cylinder 18 and leadership 40 ensured.

The piston rod 22 is continued to the left, and the connection head 10 is attached to it. So is the sleeve 12 on the piston rod 22 or the connection head 10 attached. It is also located on the continued piston rod 22 a seat (not shown) for the spring 4 ,

Similarly shows 5 the opposite end with the connection head 8th , It can be seen that here too the tube of the cylinder 18 in grooves 48 . 50 a so-called threaded head 52 is crimped. On the connection thread 54 of the thread head 52 is the connection head 8th screwed. Between the thread head 52 and the connection head 8th is a disc 56 pinched to the sleeve 14 connected. The sleeve 14 has a covenant for this purpose 58 on. This covenant 58 is on one side of the disc 56 on, and on the other side of the covenant 58 lies the feather 4 on. The spring characteristics can be adjusted to a certain extent by the collar 58 is more or less thick or suitable washers between the collar 58 and the feather 4 or between the disc 56 and the federal government 58 be inserted. In this way, the spring characteristics can be changed during manufacture. However, it is also possible to use the sleeve 14 for example in the federal government 58 form an internal thread, which with an external thread, for example on the tube of the cylinder 18 or on the screw head 52 or the disc 56 interacts. By turning the sleeve 14 can thus pre-tension the on the collar 58 adjacent spring 4 to be changed. In this way, the opening characteristics of the opening flap can be customized.

In the threaded head 52 is a passage 60 trained to the environment. If the passage 60 has a sufficiently large diameter, it enables an essentially unimpeded flow of the fluid or air, so that in the chamber 24 there is always outside pressure. In the disc 56 and in the connection head 8th are corresponding continuations of the passage 60 provided so that the connection to the environment is actually ensured.

A sliding layer 62 can on the outside of the tube of the cylinder 18 be provided to ensure low-wear functioning of the cylinder-piston unit 16 as a guide for the spring 4 sure. The inner and / or outer wall of the sleeve can be similar 12 and or 14 be provided with a sliding layer.

In the 6 is an alternative embodiment of the assembly 2 according to the present invention. In this embodiment, the spring 4 inside the cylinder-piston unit 16 arranged so that no separate telescopic sleeves 12 and 14 required are. Otherwise, this embodiment corresponds essentially to the embodiment as described above in connection with the 1 to 5 was described. Accordingly, in the embodiment of the 6 also all the details are present, as described above with reference to the embodiment of the 1 to 5 were described. Again, it can be beneficial to have a sliding layer 62 on the inside of the tube of the cylinder 18 to provide a low-wear cooperation of the as a guide for the spring 4 serving cylinder with the spring 4 sure.

A device for adjusting the spring preload 4 can be realized particularly easily in this embodiment by using the piston rod 22 relocatable, for example by means of a threaded device in the piston 20 install. For example, with a threaded connection between the piston rod 22 and pistons 20 by simply turning the piston rod 22 relative to the piston 20 the spring preload can be set according to the application. It may be convenient to have a guide for the piston 20 in the cylinder 18 provide for a twisting of the piston 20 relative to the cylinder and thus an adjustment of the spring preload of the spring 4 prevented. For example, in the piston 20 a guide channel or a guide projection can be provided, which with a corresponding guide projection or guide channel in the cylinder 18 cooperates.

Claims (10)

Vehicle, comprising a body, a pivotable opening flap connected to it via at least one hinge and a spring ( 4 ) made of elastic spring material, which is arranged such that it supports the movement of the opening flap, and further comprising a fluid damper ( 6 ), which is connected to dampen the movement of the opening flap, the fluid damper ( 6 ) as a cylinder-piston unit ( 16 ) is formed, and wherein the cylinder-piston unit ( 16 ) as an open system with two by the piston ( 20 ) separate chambers ( 24 . 26 ) and a throttle passage ( 34 ) Between the chambers ( 24 . 26 ) is formed, one of the chambers ( 26 ) against the environment and the second chamber ( 24 ) is in fluid communication with the environment. The vehicle of claim 1, wherein the spring ( 4 ) and the fluid damper ( 6 ) to a unit ( 2 ) are combined. Unit ( 2 ) made of feather ( 4 ) made of elastic spring material and fluid damper ( 6 ) to support vehicle opening flaps. Unit ( 2 ) or vehicle according to one of claims 1 to 3, wherein the spring is a coil spring. Unit ( 2 ) or vehicle according to one of claims 1 to 4, further comprising a one-way flow passage parallel to the throttle passage ( 34 ), which is designed such that a substantially unthrottled flow of the fluid in one direction of movement from the one chamber ( 24 ) to the other chamber ( 26 ) is admitted back. Unit ( 2 ) according to one of claims 1 to 5, wherein the fluid damper ( 6 ) inside the spring ( 4 ) is arranged. Unit ( 2 ) according to one of claims 1 to 6, the spring ( 4 ) inside the fluid damper ( 6 ) is arranged. Unit ( 2 ) according to claim 6 or 7, wherein the fluid damper ( 6 ) as a guide for the spring ( 4 ) is trained. Unit ( 2 ) or vehicle according to one of claims 1 to 8, further comprising a device for adjusting the spring preload. Unit ( 2 ) or vehicle according to one of claims 1 to 9, further comprising a device for adjusting the damping properties.