SE510638C2 - Air suspension - Google Patents

Abstract

An air suspension system is proposed in which at least one displacement pickup (26) and at least one additional 2/2-way solenoid valve (27) are used in order to reduce the pressure in the air suspension bellows (21) of the front right-hand wheel (3) or in the air suspension bellows (21, 15) of the right-hand side of the vehicle to a defined level in order to facilitate entry and exit, which level, however, is still so high that the vehicle body (8) does not rest on its bump stop. Refilling of the bellows (21) or bellows (21, 15) is then quicker and requires less energy. The air suspension system is intended for public local transport buses. <IMAGE>

Description

This advantage is achieved by an air suspension according to the characterizing features of the main claim.

The measures specified in the subclaims enable advantageous further developments and improvements to the air suspension.

In many air springs, air spring bellows are arranged on one of the axles, preferably on the front axle, on the left-hand side of the vehicle and on the right-hand side of the vehicle, with a common valve. According to a subclause, it is so arranged that a valve is located in a line between the common valve and the spring bellows on one side of the vehicle, this additional valve being switched to the locking position when lowering one of the body corners, which has the advantage that even in use When using a common valve on both sides when lowering to the level of inclination, only the spring bellows on one of the two vehicle sides need to be vented and filled with air. This saves energy in an advantageous way.

By lowering at least one additional body corner, boarding and disembarking is further facilitated, even if boarding or disembarking takes place through several vehicle doors.

Through the wall sensors arranged in each of the four body corners, it is advantageously possible to ensure that the inclination level, while observing tight tolerances, can be maintained immediately above the minimum height determined by the mechanical stops.

An advantageous further development of the object of invention by electronic control of the air suspension can be achieved by the pre-programming of the wall sensor to a certain specific inclination level is feasible in the electronics and that the inclination device is switched on and off by means of a mechanical switch in the cab.

Advantageously, even without the use of a pressure sensor or a pressure switch, it is ensured that a minimum residual pressure always remains in the spring bellows even with the body lowered.

Drawing An embodiment of the invention is shown in the drawing and is explained in more detail in the following description.

Description of the exemplary embodiment The air suspension described as an example is intended for a bus for public street traffic. The bus has four wheels 2, 3, 4, 5 and two axles, a front axle 6 and a rear axle 7. One of the axles or body supported by the axles 6 and 7 has the reference number 8.

The air suspension includes a compressed air supply device 9 with a compressor 10 and a storage container 11 as well as an electric or electronic control device 12. To this control device 12 several solenoid valves are connected, which are designed as multi-way valves. Thus, a central valve 13 is an electromagnetically operable valve, to which are connected each valve 16 and 17, respectively, for supplying two spring bellows 14 and 15 arranged on the rear shaft 7. In addition, a further valve 18 with three connections is connected to the central valve 13, which can assume a shut-off position 18a and a switching position 18b and which in the shut-off position 18a keeps open a flow channel monitored by means of a choke 19 from a left-spring bellows 20 to a right-spring bellows 21 and vice versa on the front axle. In the switching position 18b, the three connections of the valve 18 are connected to each other. Since in the present exemplary embodiment the two spring bellows 20, 21 are connected to the valve 18, the valve 18 can also be referred to as a common valve 18 or as a front axle valve 18.

A valve 27 is arranged in a conduit 28, which connects a connection of the front axle valve 18 to the left, front spring bellows 20. The central valve 13 has three connections and two control positions and can thereby, with accepted language use, referred to as a 3/2-way valve. Correspondingly, the front axle valve 18 can also be referred to as a 3/2-way valve and the valves 16, 17, 27 can be referred to as 2/2-way valves.

The valves 16 and 17 each have their own shut-off position 16a and 17a, respectively, and each has a flow-through position 16b and 17b, respectively. At the valve 27, in a flow-through position 27a, the connections 27 of the valve 27 are connected to each other, and in a shut-off position 27b, the flow-through is blocked.

The central valve 13 has a control position 13a and a control position 13b.

In the control position 13b, compressed air is forced from the compressed air supply device 9 to a connecting part 32 leading from the valve 13 to the valves 16, 17 and 18. When the valve 13 is in the control position 13a, the compressed air flows out of the connection 32 to the environment via an air outlet 30.

Valves 13, 16, 17, 18, 27 are operated by electric magnets. When these magnets are not affected by current, the valves 16, 17, 18 are in the respective shut-off position 16a, 17a and 18a, the valve 13 is in the control position 13a and the valve 27a is in the flow-through position 27a. When the magnets of the valves 13, 16, 17, 18, 27 are activated by current, the valves are in the control positions denoted by 13b, 16b, 17b, 18b, 27b.

The operating magnets of the valves are connected to the control device 12 via electrical lines made in broken lines in the drawing.

Adjacent vehicle wheels 2, 3, 4, 5 are located on each vehicle axle 6 and 7, respectively, two wall sensors 23 and 24 and 25 and 26, respectively, which sense the distance from a corresponding wheel 2, 3, 4, 5 to the body 8 and which emit the corresponding values for the electronic control device 12. With the sensors 23, 24, 25, 26, the level of the body 8 can be sensed at the rear and front, on the left and on the right. The electrical wires required for the connection of the wall sensors 23, 24, 25, 26 to the control device 12 are not shown in the drawing for the sake of clarity.

The body 8 has a left front corner 8a, a right front corner 8b, a left rear corner 8c and a right rear corner 8d. The wall sensor 25 senses the distance between the front left corner 8a and the front axle 6 in the portion of the vehicle wheel 2.

With the wall sensor 25, the height of the front left corner 8a is sensed relative to the shaft 6. Correspondingly, the wall sensors 23, 24, 26 sense the height of each corner 8b, 8c, 8d. For each type of wall sensor 23, 24, 25, 26, it senses the distance between the current body corner and the current shaft.

In the portion with the front left corner 8a there is a mechanical stop 36a between this corner 8a and the front axle 6. The stop 36a is, for example, a rubber buffer. When the spring bellows 20 is completely vented, the corner 8a lowers so far down that the abutment 36a abuts against the shaft 6. Since the abutment 36a is elastic, a minimum suspension is ensured even with a complete deaeration of the spring bellows 20. If after a complete deaeration of the spring bellows In order to lift the corner 8a again, the spring bellows 20 must be filled with so much air that the spring bellows 20 can again carry the load in the portion of the corner 8a. Mechanical abutments 36b, 36c, 36d corresponding to the abutment 36a are also present in the portion for each of the other corners 8b, 8c, 8d. In addition to the stops 36a, 36b, 36c, 36d or instead of these, corresponding rubber buffers serving as mechanical stops can also be attached to the shafts 6, 7.

In known vehicles with a known air suspension, instead of the front axle valve 18, the front axle 6 has only one wall sensor arranged on the front axle 6. According to the invention, however, in the preferred embodiment shown, two wall sensors 25 and 26 are arranged, namely in the portion of each front wheel 2 and 3, respectively, each wall sensor 25 and 26, respectively, is located. The wall sensor 26 of the right front wheel 3 has a special task. 10 15 20 25 30 35 510 638 e It is programmed on a so-called "inclination level", which is immediately above a minimum height of the corner 8b. This minimum height is usually determined by the rubber buffer which constitutes the stop 36b, on which the body 8 abuts when the air suspension fails, whereby an additional emergency suspension is ensured.

Mode of operation The described air suspension operates during normal operation in a known manner so that a normal height of the body 8 is predetermined, for example, from the electric control device 12. As passengers get on, the weight of the increasingly loaded body 8 increases, whereby it strives to sink. The wall sensors 23 to 26 sense a smaller distance, signal this to the control device 12, which activates the central valve 13, the two valves 16 and 17 and the front shaft valve 18 with current. The spring bellows 14, 15, 20, 21 are connected to the compressed air supply device 9 and are filled immediately to such an extent that the body 8 maintains its normal height despite a higher load.

When the desired normal height has been reached, all valves return to the respective de-energized starting position.

The drawing shows the valves in this de-energized state. On the front axle 6, during normal operation, the values from the two wall transducers 25 and 26 are equalized or only the value from one of the two wall transducers 25, 26 is evaluated. 18a and 27a.

If many passengers disembark, the central valve 13 remains in its de-energized position 13a and only the valves 16 and 17 and the front axle valve 18 are switched separately or jointly. Via the central valve 13 open in the de-energized state in the direction of the air outlet 30, the air can be diverted from the spring bellows via this air outlet 30. Thereby the spring bellows 14, 15, 20, 21 are vented and the body 18 is lowered. As soon as a wall sensor 23, 24, 25, 26 senses the desired normal height, the corresponding valve 16, 17 or 18 is switched to its de-energized, i.e. off mode.

According to the exemplary embodiment shown, it is also possible according to the invention that in addition the auxiliary valve 27 is also arranged in the line 28 from the front axle valve 18 to the spring bellows 20 of the left front wheel 2. The valve 27 is controllable by means of the control device 12. In addition 29 located in the cab (not shown), which switch is connected to the control device 12.

When the driver operates this switch 29, the normal control of the normal height is switched off via the electronic control device 12 and then only the signal from the wall sensor 26 of the right front wheel 3 is evaluated and the auxiliary valve 27 is activated and shuts off the spring bellows 20 of the left front wheel 2. 27b. The front axle valve 18 is also regulated and switched to flow 18b and via the central valve 13 open in the control position 13a, the right spring bellows 21 is vented and the body corner 8b is lowered to the inclination level programmed by the air suspension. The wall sensor 26 senses the level of the body 8 in the portion of the front right wheel 3 and as soon as the body 8 there is lowered to the level of inclination, the control device 12 connects the front axle valve 18 to the locking position 18a, which prevents further venting of the spring bellows 21. immersion of the corner 8b to the locking position 27b switched valve 27 prevents the spring bellows 20 from also being vented during the venting of the spring bellows 21.

In the event of load changes, for example during boarding and disembarking of passengers, it is also possible to automatically adjust the level of inclination. During this adjustment, the valves 16, 17 remain in the respective shown de-energized initial position 16a, 17a. The front axle valve 18 is switched by current activation to position 18b. If the central valve 13 is in position 13a, the corner 8b is lowered. For lifting, the central valve 13 is brought to the position 13b. As soon as the corner 8b has again reached the pre-programmed inclination level, the front shaft valve 18 is again switched to the inactive position 18a. This ensures that even with the simultaneous disembarkation of many passengers, the height of the exit does not increase, and the corner 8b does not come into contact with the stop 36b on the front axle 6, as many people get on, which significantly accelerates the lifting of the corner 8b after immersion. of the body 8.

When the boarding or disembarking process is completed, the driver switches off the tilting depression again by means of the switch 29.

Then the front axle valve 18 goes to its current-actuated, second position 18b and the right spring bellows 21 is filled with air until the desired normal height has been reached again. Then the front shaft valve 18 is switched back to its de-energized position 18a and the central valve 13 is transferred to its vent position 13a. The auxiliary valve 27 is switched to its electroless flow position 27a. Thereafter, regulation at all regulation points is allowed again, i.e. the air suspension works again in normal normal operation.

It is thus established that by indicating a predetermined inclination level the right spring bellows 21 is not completely vented but a pressure corresponding to the weight of the body corner 8b remains in the spring bellows 21. This is achieved by the body 8 not resting on its stop rubber buffer.

By using the two wall sensors 25, 26 on the front axle 6, it is possible in cooperation with the auxiliary valve 27 to achieve and control a certain defined inclination level. A bearing on the rubber buffer is thus certainly avoided.

Because the wall sensor 26, in cooperation with the electronic control device 12, predetermines a inclination level which is a few millimeters above the rubber buffer, the associated spring bellows 21 is not pressure-free but it is ensured that a pressure corresponding to the current load is maintained in the spring bellows 21.

In this way, a faster lifting of the body 8 is made possible, which has the consequence that the stop times of the bus are shortened at the stops. In addition, air consumption is reduced because only a small amount of air is required to re-transfer the body 8 to the desired normal level.

By a small change of the described air suspension it is also possible to lower a vehicle side, preferably the right side of the vehicle, i.e. the two body corners 8b, 3d to facilitate boarding and disembarking. In addition, it is only required that during immersion to the inclination level, the valve 17 is also set in the current-affected flow-through position 17b. As soon as the front right wall sensor 26 senses that the inclination level has been reached, the front axle valve 18 is reset to the inactivated position 18a, and as soon as the wall sensor 24 determines that the body corner 8d has reached the inclination level programmed for this corner, it is reset. valve 17 again to its non-activated position 17a. In the event of load changes, even during immersion to the inclination level, the chaos corner 8d can be adjusted by means of a corresponding short activation of the valve 17 and the central valve 13.

In the embodiment shown, the rear spring bellows 14, 15 are controlled by two valves 16 and 17 and the front spring bellows 20, 21 are operated via a common front axle valve 18. This configuration is often used. However, it is also possible to control the front axle spring bellows with two valves and the rear axle spring bellows with a common valve.

The valves 13, 16, 17 constitute a valve device 34. The valves 13, 16, 17 are electromagnetically operable, controlled directional valves. This is for example only. It is also possible to realize the valve device 34 in other ways. For example, the valves in the valve device 34 can be joined to a single control block and, if applicable, the valve 18 and the valve 27 can also be integrated in this control block.

In many countries, the boarding and alighting openings are located on the other side of the vehicle. It is of course therefore also possible to design the air suspension in such a way that another body corner is also subjected to immersion to the inclination level.

Claims (5)

510 638 10 Patent claims 1. Air suspension for vehicles with a compressed air supply device, a valve device for air filling and deaeration of spring bellows supporting a vehicle body connected to the valve device, arranged on a vehicle body, and wall sensors for sensing the height between the body and the vehicle axles. at least one first corner (8b) of the body (8) is submersible to a inclination level predetermined by a wall sensor (26) for this corner, by means of venting of a spring bellows (21) supporting this first corner, which inclination level is higher than of a mechanical abutment (36b) determined minimum height of the corner (8b), and that a deviation from the inclination level entails automatic readjustment thereto. Air suspension according to claim 1, characterized in that the first spring bellows (21) and a second spring bellows (20) arranged on the opposite side of the vehicle, are controllable via a common valve (18), the second spring bellows when immersed of the first corner (8b) is closable by means of an additional valve (27). Air suspension according to Claim 2, characterized in that the auxiliary valve (27) is interconnected in a line (28) which connects the common valve (18) to the second spring bellows (20). Air suspension according to one of Claims 1 to 3, characterized in that at least one further body corner (8a, 8c, 8d) is submersible to a inclination level sensed by a wall sensor (23, 24, 25) for this corner. Air suspension according to one of Claims 1 to 4, characterized in that the body (8) has four corners (8a, 8b, 8c, 8d), at least each of which has a wall sensor (23, 24, 25, 26) arranged for sensing the height of each corner.