CZ20002792A3 - Device and method for adjusting tire pressure in a vehicle - Google Patents

Abstract

The pneumatic control unit (22) has at least a high-pressure valve (34) and a medium-pressure valve (40), which are arranged in parallel branches (30, 32) between the compressed air source (20) and the pressure equalization pipe (25) connectable to the connecting pipe (24), and are switchable between a closed position (36) and a flow position (38), wherein at least in the branch (32) of the medium-pressure valve (40) a pressure reducing valve (42) is arranged, which adjusts the aeration pressure. When adjusting the pressure in at least one tire (12, 13) of the vehicle, an aeration pressure is applied to the wheel valve arrangement (28) for a short time, then the pressure value (po) of the tires (12, 13) in the connecting pipe (24) is measured, the aeration time (ti) or the venting time (t2) is determined from the comparison between the pressure value (p0) and the determined pressure value (pi), and then an aeration pressure or a venting pressure is applied to the wheel valve arrangement (28) for a specified time (ti, t2) to aerate or vent the tire (12, 13).

Description

Device and method for adjusting the tire pressure of a vehicle

Technical field

The invention relates to a device according to the features of the preamble of claim 1. The invention further relates to a method for adjusting the pressure with such a device.

BACKGROUND OF THE INVENTION

Tire pressure adjusting devices and methods are particularly used in agriculture to adapt agricultural vehicles such as tractors to the conditions of use. With the increasing performance of agricultural vehicles, these are being developed for an increasing overall weight. In order to avoid the resulting load and soil consolidation with undesirable side effects, vehicles may be equipped with tire pressure adjusting devices which, for example in field work, reduce the tire pressure compared to the road pressure.

EP-B1-0 164 917 discloses a central tire filling system with steering means and wheel valve arrangement. The control means provides an inlet pressure for the first relief valve connection. The relief valve comprises a second port open to the atmosphere and a third port which is connected to the co-rotating arrangement of the wheel valves via a connecting pipe and a rotary bushing. The first connection and the third relief valve connection are connected when the inlet pressure exceeds the pressure at the third connection. The third port is connected to the vent port when the pressure at the third port exceeds the inlet pressure. The arrangement of the wheel valves is associated with an inflated tire. It allows flow when its inlet side generates a pressure that exceeds the first reference pressure and when the tire pressure is above the minimum wheel reference pressure. The tire is vented via a relief valve located in front of the rotary grommet. To this end, a venting pressure must be supplied to the system, so that the wheel valve arrangement assumes its open position. This venting pressure counteracts the venting of the pressure chamber itself, which is an obstacle to the venting process. Accordingly, the vent connection located remotely from the pressure chamber also acts as a barrier to the venting process and is an obstacle thereto.

DE-OS-38 36 105 discloses a tire pressure control device for off-road motor vehicles consisting of a stationary valve combination for one wheel of one rotary bushing for one pressure equalization line as well as for the control line and one wheel of one co-rotating valve combination. The stationary valve combination comprises a relay valve, at least one presetting valve and one shut-off pressure setting valve. The co-rotating valve combination comprises a wheel adjusting valve which is opened by a pressure pulse on the equalizing line and closed by the adjusting pressure on the adjusting line, and a downstream quick-release valve which is responsible for deflating the air from the tire. The discharge opening of the quick release valve may have a check valve behind it. This version must be • 9

both the adjusting line and the equalizing line are connected to the wheel adjusting valve by means of a rotary bushing. It's expensive and expensive.

FR-A-1,247,604 discloses a tire supply system through which the tire pressure of a vehicle can be changed individually or together. The system comprises a pressure source, a manual control, a pressure gauge, and a plurality of valves and piping, with the tires assigned to a spool valve that is closed when there is no or only low pressure in the system through which the tire is connected to the pressure source when the first , a higher pressure, and through which the tire is vented when an additional pressure is generated in the system that exceeds the first pressure.

SUMMARY OF THE INVENTION

The problem solved by the invention resides in the complicated arrangement of known tire feeding systems and in the time-consuming venting.

The problem is solved according to the invention in accordance with claims 1 and 13, respectively. Further advantageous embodiments and further embodiments of the invention result from the dependent claims.

The device according to the invention for adjusting the pressure in at least one vehicle tire comprises a pneumatic control unit, a pressure sensor, a rotary bushing and a co-rotating arrangement of wheel valves with different positions. The device is connected to a source of compressed air and the control unit is connected via a connecting pipe and a rotary bushing to a wheel valve arrangement whose setting depends on the pressure level in the connecting pipe. The wheel valve arrangement has at least a closing position, a flow position as well as a venting position open towards the ambient air. The wheel valve arrangement assumes its flow position when there is aeration pressure in the connecting pipe. It assumes the venting position when the connecting line has a pressure that exceeds the aeration pressure by at least a predetermined value, and assumes its closing position when the connecting line is a closing pressure that is at least a predetermined pressure differential value below the aerating pressure.

According to the invention, the pneumatic control unit comprises at least one high-pressure valve and one medium-pressure valve, which are arranged in parallel branches between the source of compressed air and the pressure equalization line and are connectable between the closing and flow position. A pressure reducing valve is provided in the medium pressure valve branch to adjust the aeration pressure. The pressure set by the pressure reducing valve is greater than the maximum required tire aeration pressure, but less than the pressure required to bring the wheel valve arrangement to its venting position. When the pressure equalizing line is connected to the connecting line, the wheel valve arrangement assumes its venting position when the high pressure valve is opened. It assumes the flow position when the medium-pressure valve is opened and the wheel valve arrangement is loaded by the pressure reduced by the pressure-reducing valve.

Venting takes place directly on the wheel, reducing the time required to vent. Only the pipeline must be routed through the rotary grommet, as the setup settings are 9 9 9 · ·· ·

99 9 9 99 9 99 · 9 * · · · Wheel valves are performed solely by the pressure in the connecting pipe and not by the additional adjusting pipe.

The device according to the invention allows a rapid modification of the limit values when changing tires and taking into account the load. It is particularly advantageous when there is a frequent change in tire pressure so that it can be adjusted optimally and smoothly according to the tire manufacturer according to the working conditions of the wheel load and the current driving speed. The current tire pressure limits can be updated when the tires are changed either by the driver or by means of a suitable transponder integrated in the tire. The actual tire load can be determined from the vehicle's deflection.

If the pressure is to be adjusted on a plurality of vehicle tires, these tires are, for example, connected to a common stationary pneumatic control unit. This can reduce the number of structural elements. The pneumatic control unit is preferably a modular valve block.

An advantageous further development of the device according to the invention can be seen in that not only the tire pressure of one vehicle but also the tire pressure of one or more of the trailers associated with the vehicle can be adjusted by means of a stationary pneumatic control unit.

It is advantageous to design the wheel valve arrangement in the form of a spool valve. The spool valve assumes its position depending on the pressure in the connecting pipe. The gate valves are structurally simple and insensitive to flow. They are often used and are therefore cost effective.

• ·

Advantageously, the arrangement of the wheel valves is loaded by a spring which counteracts the effect of compressed air in the connecting line. By dimensioning the spring, the connection centers of the thrust of different valve positions can be defined.

Preferably, the pneumatic control unit comprises at least one connection valve. It has a vent position to open the connecting pipe to the surroundings. If the transfer valve is in this position, the connection line is depressurized, which means less stress. In the depressurized connecting line, the wheel valve arrangement advantageously occupies its closing position so that there is no reduction in tire pressure through this arrangement.

Advantageously, the pneumatic control unit comprises at least one transfer valve which lies between the pressure equalizing line of the control unit and the connecting line. The reversing valve is switchable between the venting position and the flow position. In the deaeration position, the connecting pipe is vented and thereby relieved. At the same time, the pressure equalization line is closed so that its pressure remains at the correct level. In the flow position, the connecting line is connected to a pressure equalizing line.

In the preferred case, the tires of at least one axis of the vehicle and / or of the coupled trailer are connected via respective wheel valve and rotary grommet configurations to a connecting line corresponding to only one axis. The connecting line can be connected to the pressure equalizing line of the pneumatic control unit via the respective changeover valve. The tire pressure of one axis is set together in this embodiment, so that the same tire pressure is set in all tires of one axis. This is advantageous because the tires of one axis are usually subjected to the same load. In this way, the number of individual parts forming the pneumatic control unit is reduced.

In order to enable control and, in particular, remote adjustment and remote control of the device from, for example, the driver's position of the vehicle, it is advantageous to design the changeover valves and / or the high pressure valve and / or the medium pressure valve as solenoid valves.

The changeover valves and / or the high-pressure valve and / or the medium-pressure valve assume their closing position in the current-free state. In the case of transfer valves, the closing position also corresponds to the venting position for the connecting pipe. Thereby the arrangement of the wheel valves in the current-free state is in its closing position, whereby the tires are not vented in the event of a power failure.

The data obtained by means of a pressure sensor in the pressure equalization line is preferably processed by an electrical or electronic unit. Thus, it is possible for the electrical or electronic unit to automatically carry out the venting or aeration step required to achieve a preselected or necessary pressure.

By means of the electrical or electronic unit, the arrangement of the wheel valves can be situated in the desired position for venting and aeration or in the closing position. Thus, the electrical or electronic unit permits inspection and testing of the arrangement of the wheel valves. Multiple wheel valve configurations allow controlled pressure adjustment and pressure control.

The method according to the invention for adjusting the pressure in at least one tire preferably works with the described device according to the invention. Aeration pressure is briefly applied to the wheel valve arrangement to assume the flow valve position. Subsequently, the present value of the tire pressure in the connecting pipe is measured. The aeration time is determined from the comparison between the instantaneous pressure value and the predetermined pressure value. Subsequently, the aeration pressure or the venting pressure is set for a specified period of time on the arrangement of the wheel valves in order to supply or vent the tire. The method steps may be controlled by an electronic unit in which an initial predetermined functional relationship is stored between the pressure difference of the current and the desired pressure and the feeding time or venting. The functional relationship is varied with respect to the initial pressure differential and the sum of the individual feed or vent times to accommodate particular ratios, in particular the actual flow characteristics and tire parameters. Said method steps allow the system to be adapted to changes in flow characteristics and tire parameters. As a result, tire pressure can be determined and adjusted according to changing road conditions, wheel load and speed. This allows accurate and rapid tire pressure adjustment.

It is advantageous to carry out said method steps repeatedly until the pressure value lies within a specified tolerance range, with an interactive approach to the desired pressure.

• · · · · ♦ «*

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, as well as further advantages and advantageous further embodiments and embodiments of the invention, will be described and explained in more detail with reference to the drawings, in which: FIG.

FIG. 1 is a schematic representation of a device according to the invention for a four-tire vehicle; and FIG. 2 is a diagram for explaining how to adjust the tire pressure.

DETAILED DESCRIPTION OF THE INVENTION

A vehicle (not shown), for example an agricultural tractor, is provided with a device 10 for adjusting the pressure of its tires 12, 13. The apparatus 10 shown in Fig. 1 comprises a pneumatic control unit 22 which is connected via a connecting line 24 to four tires 12, 13. Each tire has one rotating bushing 26 that connects the connecting line 24 to the co-rotating wheel valve arrangement 28. Each wheel valve arrangement 28 is connected via a connecting line 29 to the interior of the respective tire 12, 13. The device is connected to a compressed air tank 14 via a supply line 16 in which an overflow valve 18 is arranged. The compressed air tank 14 is supplied by compressed air source 20 with compressed air. For example, the compressed air source 20 is a compressor that supplies a braking device with a higher braking priority.

♦ ♦ ·· ♦ ·! ··· · i · # · * *

The pneumatic control unit 22 is fixed stationary in the vehicle. The supply line 16 coming from the compressed air tank 14 is divided in the control unit 22 into two branches 30, 32, the first branch 30 comprising a high-pressure valve 34 in the form of a spring-loaded solenoid valve with closing position 36 and flow position 38. a medium pressure valve 40 is provided in the form of a second identical solenoid valve, which is preceded by a pressure reduction valve 42. Downstream of the high pressure valve 34 and the medium pressure valve 40, the two branches 30, 32 are led into a pressure equalization line 25. The pressure equalization line 25 is connected to a pressure sensor 44. The pressure equalization line 25 extends through two identical transfer valves 46, 48 in the form of spring-loaded solenoid valves having a deaeration position 49 and a flow position 38 up to the tire connecting line.

24, which provides the connection in a flow-through form

The slide at one end is pushed into its closing

The wheel valve arrangement 28 is a spool valve with a closing position 54 ', a position 54''and a venting position 54' ^z , the wheel valve arrangement 28 being the action of the spring 56, thereby positioning it. At the other end, the slider is subjected to pressure in the control line 58, which is connected to the connecting line 24. In accordance with the pressure level indicated by the control unit 22 in the connecting line 24, the wheel valve arrangement 28 occupies one of its positions 54, 54 / ', 54'. ''.

The pneumatic control unit 22 is connected to an electronic unit 60 which adjusts the »9 * ·

Valves 46, 48, medium pressure valve 40 and high pressure valve 21, and evaluate the pressure sensor readings.

The operation of the device shown is described below.

The overflow valve 18 arranged in the supply line 16 is opened only when there is a predetermined minimum pressure in the compressed air tank 14. This ensures that compressed air is taken from the compressed air tank 14 only when the pressure is above the minimum pressure to secure the compressed air braking device. To determine whether the compressed air tank 14 has the necessary operating pressure to operate the device, the high pressure valve 34 is opened. The compressed air tank 14 is thus connected to a pressure sensor 44. A pressure sensor 44 delivers the detected data to the electronic unit 60 to prevent the aeration process if sufficient compressed air is not available.

For tire aeration, the medium pressure valve 40 is set via its electronic unit 60 to its flow position 31. As a result, the tire aeration transfer valve 46 of the front axle 22 'or the tire aeration transfer valve 48 of the rear axle 52, or both As the pressure reducing valve 42 is provided upstream of the medium pressure valve 40, the aeration pressure reduced to the pressure in the compressed air tank 14 is set in the connecting line 24. This passes through the connecting line 24 and the control line 5-8 to the slide valve 28 of the wheel valve, the wheel valve arrangement 28 assuming its flow position 54 '', and the tires 12, 13 are aerated.

·· · ♦ · · · φ · ·

ΦΦ 99 ι »1:

Φ »» • • • •

Pneumatik when the tires 12, 13 are vented, the medium pressure valve 40 is closed and the transfer valve 46 and / or transfer valve 48 is set to the flow position 3 $. The operating pressure in the compressed air tank 14 directly sets the wheel valve arrangement 28 to the breather position 54 '' '. The interior of the tires 12, 132 is directly vented to the atmosphere without venting due to control pressure or a long way through the duct.

If the tires 12, 13 are to be neither aerated nor vented, then all solenoid valves 34, 40, 46, 48 are de-energized and therefore closed. The transfer valves 46, 48 in this position open the connection line 24 to the environment, so that there is no pressure on the slide valve 28 of the wheel valve and this is in the closing position 54 'in which the connection line 29 is closed.

To check the tire pressure, the aeration process is first carried out briefly to bring the wheel valve arrangement 28 to its flow position 54 / '. Then the solenoid valve 40 is closed and the pressure sensor 44 measures the pressure in the connecting line 24, which corresponds to the tire pressure 12, 13.

Between the aeration, venting, or measurement processes, the transfer valves 46 and 48 are in their venting position, whereby the connecting conduit 24 is connected to the environment, whereby the area of the rotary grommet 26 is also free of pressure.

The adjustment of the solenoid valves 34, 40, 46 and 48 in the pneumatic control unit 22 is performed by the method described in FIG.

· »4 *

4 4 ·

4 44 ·· 4 · »♦ · 4

4 4 • 4

At certain times, which are given either by the electronic unit 60 or also manually, for example by the vehicle operator, the tire pressure control process is started. This requires first measuring the pressure p ₀ in one or both pairs of tires. For this purpose, the aeration pressure (by opening the valves 40 and 46 and 48, respectively) is briefly applied to the wheel valve arrangement 28. Subsequently, the tire pressure p _{0 of the} tires 12, 13 in the connecting pipe 24 is measured by means of a pressure sensor 44. From the measured tire pressure, the electronic unit determines whether the tire pressure needs to be adjusted. This is due to the comparison between the pressure p ₀ and the specified pressure pi. If the pressure P _0, pi differ from each other, conveys the electronic unit 60 to the delay required for the aeration or deaeration process. The aeration or deaeration pressure is set to the wheel valve arrangement 28 by adjusting the solenoid valves 34, 40, 46, 48 for the required time delay t _x , so that the aeration or deaeration of the tires 12, 13 is achieved. pressure measurement. No Reply measured pressure value p _m again set pressure £ i, the process is repeated. This is done until the selected value ρ _χ is reached. In this way, iterative approximation to the desired value ρχ is achieved. Provision can be made for the process to be terminated when the achieved value lies within a specified tolerance pressure range T or when a number of aeration or venting processes are performed. The process also ends when the tire is defective and the required pi pressure cannot be achieved.

• 4 »44 ·· * · 44

4 4 * 4 4

4 44 4 4 J J 4 44 · 44 4 * »» »

The described process steps are controlled by an electronic unit 60 in which is stored a theoretical initial functional relationship between the difference F tire pressure 12, 13 and the necessary aeration or deaeration time those t _second With this theoretical relation is achieved by setting iterative carried aeration and / or venting the time t _{the second} If the tire pressure reaches the tolerance range T, the aeration or deaeration process is terminated. The electronic unit 60 now provides aeration and venting of the time t ₂ G true functional relationship, which memorizes and use it then performs subsequent aeration and venting processes. In this way, the process can be adapted to the actual flow conditions in the system.

In the illustrated embodiment, the two tires 12 of the front axle 50 and the two tires 13 on the rear axle 52 of the vehicle, not shown, are simultaneously adjusted. However, it is also possible to adjust each tire 12, 13 individually or also the whole vehicle tires 12, 13 together.

It is also possible to include in the device tires of a trailer connected to the vehicle. It is possible here to adjust the trailer tires, for example, individually, in pairs or together with the tires 12 of the vehicle.

While the invention is described with only one exemplary embodiment, many variations, modifications, and variations within the scope of the present invention will become apparent to those skilled in the art from the present description and drawings.

Claims (10)

PATENT CLAIMS 1. A device for adjusting the pressure in at least one tire (12, 13) of a vehicle with a pneumatic control unit (22), a pressure sensor (44), a rotary bushing (26) corresponding to at least one tire (12, 13) and an arrangement (28) of wheel valves rotating together with the tires (12, 13) and adjustable in different positions (54', 54, 54'''), wherein the device (10) is connected to a source (20) of compressed air and the control unit (22) is connected to the arrangement (28) of wheel valves via a connecting line (24) and a rotary bushing (26), the position (54', 54'', 54''') of which depends on the pressure level in the connecting line (24), wherein the arrangement (28) of wheel valves has at least a closed position (54'), a flow position (54''), in which the connection between the control unit (22) and at least one tire (12, 13), as well as a venting position (54''') opening at least one tire (12, 13) to the ambient air, the wheel valve arrangement (28) assuming its flow-through position (54'') when an aeration pressure is generated in the connecting line (24), assuming its venting position when an aeration pressure is generated in the connecting line (24) which exceeds the aeration pressure by at least a specified value, and assuming its closing position when a closing pressure is generated in the connecting line (24) which lies below the aeration pressure by at least a specified pressure difference, characterized in that the pneumatic control unit (22) has at least a high-pressure valve (34) and a medium-pressure valve (40), which are arranged in parallel branches (30, 32) between the compressed air source (20) and the pressure equalizing by a pipe (25) connectable to the connecting pipe (24), and are switchable between a closed position (36) and a flow position (38), and that at least in ♦ 9 99 99 9 *9 * 9 9 99 9 9 9 9 · 9 9 9 9 99 99 99 99 9 9 9 9 9 · 9 9 9 9 9 9 A pressure reducing valve (42) is arranged in the branch (32) of the medium-pressure valve (40), which adjusts the aeration pressure. 2. The device according to claim 1, characterized in that the pneumatic control unit (22) is connected to the tires (12, 13), each tire having its own rotating bushing (26) and wheel valve arrangement (28). 3. Device according to one of claims 1 or 2, characterized in that the pneumatic control unit (22) is connected to at least one tire. trailer, attached to a vehicle, tyres. to set up pressure in this 4. Equipment according to one from claims 1 to 3, mark moving thus that the pneumatic control unit (22) is stored in vehicles stationary. 5. Equipment according to one from claims 1 to 4, mark moving thus that the arrangement (28) wheel valves are made in the form of a gate valve, which shows least closing position (54' ) , flow-through position (54'') and ventilation position (54'''). 6. Equipment according to one from claims 1 to 5, characterized in that the wheel valve arrangement has at least one spring (56) which acts against the compressed air in the connecting line (24) and determines the switching pressure values for the different valve positions. *« ·♦ • · « · • · ♦ * · * · · • · * ♦ ·* · · 7. Device according to one of claims 1 to 6, characterized in that the pneumatic control unit (22) comprises at least one switching valve (46, 48) which has a venting position (49) opening the connecting line (24) to the surroundings. 8. Device according to one of claims 1 to 7, characterised in that the pneumatic control unit (22) has at least one switching valve (46, 48) which is located between the pressure equalisation line (25) of the control unit (22) and the connecting line (24) and which is between a venting position (49), in which the connecting line (24) is vented and the pressure equalisation line (25) is closed, and can be switched to a flow position (38), in which the connecting line (24) is connected to the pressure equalisation line (25). 9. Device according to one of claims 1 to 8, characterised in that the tyres (12, 13) of at least one axle (50, 52) of the vehicle and/or the attached trailer are connected to the respective connecting line (24) via the respective wheel valve arrangements (28) and the rotary bushing (26) and that the connecting line (24) can be connected to the pressure equalisation line (25) of the pneumatic control unit (22) via the respective switching valve (46, 48). 10. Device according to one of claims 1 to 9, characterized in that the switching valves (46, 48) and/or the high-pressure valve (34) and/or the medium-pressure valve (40) are designed as solenoid valves which can be controlled by an electric or electronic unit (60). 11. Device according to claim 10, characterized in that the switching valves (46, 48) and/or the high-pressure valve (34) and/or the medium-pressure valve (40) assume their closed position (36) in the de-energized state. 12. Device according to at least one of claims 1 to 11, characterized in that a pressure sensor (44) is connected to the pressure equalization pipe (25), which transmits the captured measured pressure values to an electrical or electronic unit (60), which adjusts the valves of the control unit (22) depending on the detected pressure level. 13. A method for adjusting the pressure in at least one tire (12, 13) of a vehicle with a device in particular according to one of claims 1 to 12, characterized in that an aeration pressure is applied to the wheel valve arrangement (28) for a short time, the pressure value (p ₀ ) of the tires (12, 13) in the connecting pipe (24) is subsequently measured, the aeration time (ti) or the venting time (t ₂ ) is determined from the comparison between the pressure value (p ₀ ) and the determined pressure value (pi ) and subsequently an aeration pressure or the venting pressure is applied to the wheel valve arrangement (28) for a determined time (ti, t ₂ ) to perform aeration or venting of the tire (12, 13), the method steps being controlled by an electronic unit (60) in which the initial functional relationship between the pressure difference and the aeration or venting time (ti, t ₂ ) is stored and that the functional relationship is changed with regard to the initial pressure difference and the sum of the individual aeration or deaeration times.