Tyre pressure control device, agricultural utility vehicle, and construction machine

Abstract

The invention relates to a tyre pressure control device (10) comprising a hub carrier (11) and a wheel head (12) rotatably mounted on the hub carrier (11), wherein a first air duct (20) extends through the hub carrier (11), through a first rotary union (21) and through the wheel head (12) to a first tyre connection (15), and wherein a second air duct (22) extends through the hub carrier (11), through a second rotary union (23) and through the wheel head (12) to a second tyre connection (16). The tyre pressure control device (10) according to the invention is characterised in that the first tyre connection (15) and the second tyre connection (16) extend to a common valve (30) and in that the common valve (30) is designed as an air-pressure-controllable valve (30) that is closed in the unpressurised state. The present invention also relates to a corresponding agricultural utility vehicle and to a corresponding construction machine.

Description

[0001] Tire pressure control device, agricultural vehicle and construction machine

[0002] The present invention relates to a tire pressure control device according to the preamble of claim 1 as well as a corresponding agricultural utility vehicle and a corresponding construction machine.

[0003] It is known in the art that, for example, in agricultural machinery, adjusting tire pressure is beneficial when switching from operation in fields or arable land to operation on the road. Increasing tire pressure, for example, can reduce tire flexion, thus preventing unnecessary tire wear and fuel consumption during road travel. Conversely, reducing tire pressure increases the tire contact area, thus reducing surface pressure on a field and mitigating soil damage.

[0004] DE 10 2017 21 1 574 A1 discloses a rotary union for a tire inflation system, comprising an axle housing and a wheel axle rotatably mounted in the axle housing, which wheel axle has a wheel mounting flange for attaching a wheel rim. The wheel axle is accommodated, at least in sections, by a bushing sleeve that is non-rotatably connected to the wheel axle and supported by a radial bearing against a bearing seat within the axle housing. A compressed air duct is provided within a cylindrical wall of the bushing sleeve, which communicates, on the one hand, with a pressure connection attached to the axle housing and, on the other hand, with a tire connection attached to the bushing sleeve.Furthermore, a further pressure connection is attached to the axle housing, wherein the further pressure connection opens into an annular channel communicating with the compressed air channel, which is formed by a pair of elastic sealing rings extending between a cylindrical outer side of the bushing sleeve and a cylindrical inner side of the axle housing. However, the known tire pressure control systems are disadvantageous in that they cannot reliably prevent an unintentional loss of tire pressure through the system, for example, due to a malfunction of a valve.

[0005] It is an object of the invention to propose an improved tire pressure control device.

[0006] This object is achieved according to the invention by the tire pressure control device according to claim 1. Advantageous embodiments and further developments of the invention emerge from the dependent claims.

[0007] The invention relates to a tire pressure control device, comprising a hub carrier and a wheel head rotatably mounted on the hub carrier, wherein a first air duct runs through the hub carrier, through a first rotary feedthrough and through the wheel head to a first tire connection and wherein a second air duct runs through the hub carrier, through a second rotary feedthrough and through the wheel head to a second tire connection.

[0008] A tire pressure control device is therefore intended, in particular, for a vehicle. The vehicle can advantageously be an agricultural machine. However, it can also be a construction machine or an off-road vehicle, for example, a wheeled armored personnel carrier, a civilian off-road vehicle, or an off-road truck.

[0009] The tire pressure control device has a first air duct and a second air duct. Both the first air duct and the second air duct extend through a hub carrier of the vehicle and through a wheel head rotatably mounted on the hub carrier. Advantageously, the first air duct and the second air duct are formed as bores in the hub carrier and the wheel head, respectively.

[0010] The holes representing the first air channel and the second air channel preferably run largely parallel in both the hub carrier and the wheel head. The hub carrier and the wheel head are thus components of the tire pressure control device, as they contain the holes representing the first and second air channels.

[0011] The first air channel opens into a first tire connection, wherein the first tire connection can be designed, for example, as a compressed air interface, which enables the establishment of a pressure-tight connection to a compressed air hose leading away from the first tire connection.

[0012] Likewise, the second air channel opens into a second tire connection, whereby the second tire connection can also be designed as a compressed air interface, which enables the creation of a pressure-tight connection to a compressed air hose leading away from the second tire connection.

[0013] The first and second tire connections are preferably arranged on an outer side of the first and second wheel heads, respectively, in such a way that they are easily accessible to a driver of the vehicle having the tire pressure control device, at least when the vehicle is stationary.

[0014] The hub carrier and the wheel head are advantageously part of an axle. The axle can be designed as a drivable axle, so that the wheel head is also drivable. The axle can also be designed as a steerable axle, so that the hub carrier and the wheel head can be pivoted in a steering movement. Alternatively, the axle can also be designed as a non-drivable or non-steerable axle.

[0015] It is also conceivable, however, that the hub carrier and wheel head are not intended as part of an axle. For example, the hub carrier and wheel head can alternatively be assigned to an independent wheel suspension.

[0016] The tire pressure control device according to the invention is thus widely and flexibly applicable. According to the invention, the first tire connection and the second tire connection extend to a common valve, and the common valve is designed as an air pressure-controllable valve that is closed in the depressurized state.

[0017] The common valve is advantageously arranged on the vehicle tire, for example on the so-called tire valve or even directly on the tire instead of the so-called tire valve.

[0018] Preferably, the first air channel runs from the first tire connection via a compressed air hose to the common valve and the second air channel runs from the second tire connection via a compressed air hose to the common valve.

[0019] Because the common valve is designed to be controlled by compressed air, meaning it can be controlled by pressurized air and is simultaneously closed when depressurized, tire pressure loss from the vehicle tire can be reliably prevented when not actuated. In the event of a leak in the tire pressure control device, tire pressure loss from the vehicle tire cannot occur because the common valve is automatically locked or closed, thus counteracting tire pressure loss. This represents a particular advantage over tire pressure control devices that only have a single air channel.

[0020] Furthermore, the tire pressure control device according to the invention allows the air pressure in the vehicle tires to be adjusted at any time to the respective surface on which the vehicle equipped with the tire pressure control device is located. For example, when an agricultural machine is traveling along a road, the air pressure in the vehicle tires can be increased to reduce fuel consumption and tire wear. When traveling on a field, however, the air pressure in the vehicle tires of the agricultural machine can be reduced to keep soil compaction as low as possible while simultaneously enabling greater grip. According to a preferred embodiment of the invention, the common valve comprises a return spring that counteracts the application of air pressure.A mechanical return spring represents a comparatively cost-effective and effective way to reliably hold the common valve in its initial position or return it to its initial position when compressed air is not applied. In this case, the initial position is the closed position of the common valve.

[0021] According to a further preferred embodiment of the invention, the second air channel is designed to apply air pressure to the common valve, causing the common valve to open. Thus, no compressed air is introduced into the vehicle tire via the second air channel; instead, the second air channel serves exclusively to control the common valve. When the common valve is subjected to air pressure via the second air channel and the resulting force is greater than the return force of the return spring, the common valve begins to open.

[0022] From a functional point of view, the second air duct is therefore a control duct.

[0023] The common valve can be designed as a digitally switching or as an analog adjustable valve.

[0024] According to a further preferred embodiment of the invention, the first air duct is designed to supply or discharge compressed air to a vehicle tire depending on a valve position of the common valve and depending on an air pressure in the first air duct. Thus, compressed air can be introduced into the vehicle tire via the first air duct in order to increase its tire pressure. Likewise, compressed air can also be discharged from the vehicle tire via the first air duct in order to reduce its tire pressure. In order to increase or reduce the tire pressure, a prerequisite in any case is that the air pressure in the second air duct is sufficiently high to move the common valve into the open state against its restoring force.When the common valve is open, the first air channel is now connected to the interior of the vehicle tire, so that pressure equalization can occur between the first air channel and the vehicle tire as long as the common valve remains open.

[0025] Depending on whether the air pressure in the first air channel or in the vehicle tire is higher, the tire pressure in the vehicle tire is increased or reduced.

[0026] If the air pressure in the first air channel is higher than in the vehicle tire, compressed air flows into the vehicle tire and increases the tire pressure in the vehicle tire.

[0027] If, however, the air pressure in the first air channel is lower than in the vehicle tire, compressed air flows out of the vehicle tire and reduces the tire pressure in the vehicle tire.

[0028] From a functional point of view, the first air duct is therefore a pressure duct.

[0029] The tire pressure control device is designed as a so-called “two-wire system” with a pressure channel and a control channel.

[0030] According to a further preferred embodiment of the invention, it is provided that the first air duct has a valve-controlled air outlet through which compressed air released from the vehicle tire can be released from the first air duct.

[0031] The air outlet can be located either in the wheel hub or in the wheel head. The air outlet is preferably a hole connecting the first air channel to the ambient atmosphere of the tire pressure control device, with this connection being closable by a valve. When the valve is open, pressure equalization with the ambient atmosphere can occur; when the valve is closed, however, pressure equalization cannot occur. The closed position also prevents moisture and dirt from entering the first air channel.

[0032] This allows compressed air from the vehicle tire to be released into the environment via the air outlet as needed. Likewise, compressed air still in the first air channel after the tire has been inflated and should no longer be supplied to the tire, for example, because the tire has already reached its target air pressure, can be released into the environment.

[0033] The valve can, for example, be designed as an electromagnetically actuated valve.

[0034] According to a further preferred embodiment of the invention, the first air channel in the hub carrier and the wheel head has an identical diameter. This ensures that the first air channel has no constrictions that could slow the flow of compressed air. Thus, the vehicle tire can be filled with compressed air relatively quickly.

[0035] In particular, the first air channel in the hub carrier and in the wheel head has a diameter of 6 mm.

[0036] According to a further preferred embodiment of the invention, the first rotary union and the second rotary union are arranged axially between a first rotary bearing and a second rotary bearing, wherein the first rotary bearing and the second rotary bearing rotatably mount the wheel head on the hub carrier. Thus, the stability of the mounting of the wheel head on the hub carrier is not compromised, in particular not by a shortening of the axial distance between the first rotary bearing and the second rotary bearing.

[0037] Preferably, the first rotary union and the second rotary union each comprise a metal race and an annular rubber seal. The metal race is advantageously arranged directly on the hub carrier, while the annular rubber seal is arranged on the race and bears against the wheel head.

[0038] Particularly preferably, the raceway of the first rotary union and the raceway of the second rotary union are a common, double raceway. The first and second rotary unions therefore have a common raceway. This simplifies the assembly of the first and second rotary unions.

[0039] According to a further preferred embodiment of the invention, it is provided that the tire pressure control device further comprises a third air channel and that an intermediate chamber is provided axially between the first rotary feedthrough and the second rotary feedthrough, wherein the intermediate chamber is connected to the third air channel, which connects the intermediate chamber to an atmospheric ambient pressure.

[0040] Since a slight escape of compressed air from the rotary unions cannot be ruled out, particularly at high air pressure in the area of ​​the rotary union, the provision of the intermediate chamber has the advantage that the compressed air escaped in this way can be collected in the intermediate chamber instead of exerting pressure on the rotary bearings and thereby possibly adversely affecting their running behavior.

[0041] The third air duct provides a connection between the intermediate chamber and the ambient atmosphere so that the escaped compressed air can be released into the environment.

[0042] According to a further preferred embodiment of the invention, the tire pressure control device further comprises a compressed air source. The compressed air source can, for example, be designed as a rotary vane pump driven by an electric motor, which provides the required air pressure to fill the vehicle tire with compressed air via the first air channel and to control the common valve via the second air channel.

[0043] According to a further preferred embodiment of the invention, the hub carrier is designed as a joint housing. In this case, the wheel head or the vehicle tire is arranged on the vehicle in a steerable manner.

[0044] The invention further relates to an agricultural utility vehicle comprising a tire pressure control device according to the invention.

[0045] This results in the advantages already described in connection with the tire pressure control device according to the invention also for the agricultural utility vehicle according to the invention.

[0046] Finally, the invention also relates to a construction machine comprising a tire pressure control device according to the invention.

[0047] Thus, the described advantages also apply to the construction machine according to the invention.

[0048] The invention is explained below by way of example with reference to embodiments shown in the figures.

[0049] They show:

[0050] Fig. 1 shows, by way of example and schematically, a hub carrier and a wheel head of a tire pressure control device according to the invention,

[0051] Fig. 2a-b shows, by way of example and schematically, a cross-section through a partial section of Fig. 1,

[0052] Fig. 3a-b show, by way of example and schematically, a cross-section through a further partial section of Fig. 1,

[0053] Fig. 4 shows, by way of example and schematically, a cross section through yet another partial section of Fig. 1 and Fig. 5 shows, by way of example and schematically, a possible embodiment of a common valve.

[0054] Identical objects, functional units, and comparable components are designated by the same reference symbols throughout the figures. These objects, functional units, and comparable components are identical in terms of their technical features, unless explicitly or implicitly stated otherwise in the description.

[0055] Fig. 1 shows, by way of example and schematically, a hub carrier 11 and a wheel head 12 of a tire pressure regulating device 10 according to the invention. The hub carrier 11 is designed, for example, as a joint housing 11. A first connection 13 and a second connection 14 can be seen on the hub carrier 11. The first connection 13 makes it possible to connect a compressed air line to a compressed air source with the first air duct 20 in the hub carrier 11. The second connection 14 makes it possible, in a similar manner, to connect a compressed air line to a compressed air source with the second air duct 22 in the hub carrier 11. Also visible are a first tire connection 15 and a second tire connection 16. The first tire connection 15 makes it possible to connect a compressed air line to a common valve 30 with the first air duct 20 in the wheel head 12.The second tire connection 16 makes it possible, in an analogous manner, to connect a compressed air line to a common valve 30 with the second air channel 22 in the wheel head 12.

[0056] Fig. 2a shows, by way of example and schematically, a cross-section through a partial section of Fig. 1. It shows the first air duct 20, which is formed as a bore 20 in the wheel head 12. The diameter of the bore 20 is, for example, 6 mm.

[0057] The first air duct 20 is designed, for example, to supply or discharge compressed air to a vehicle tire, which can be arranged on the wheel head 12, depending on a valve position of the common valve 30 and the air pressure in the first air duct 20. The first air duct 20 extends from the hub carrier 11 via a first rotary union 21 into the wheel head 12 and from the first tire connection 15 via a compressed air line (not shown) to the common valve 30.

[0058] As can be seen, the first air duct 20 has an opening to the first rotary union 21, so that compressed air can flow from the first air duct 20 in the hub carrier 11 through the first rotary union 21 into the first air duct 20 in the wheel head 12. The first rotary union 21 comprises a race 21" and an annular rubber seal 21'.

[0059] Adjacent to the first rotary union 21 is a second rotary union 23 which is assigned to the second air duct 22. The second rotary union 23 also comprises a race 23" and an annular rubber seal 23'. As can be seen, the first rotary union 21 and the second rotary union 23 are arranged axially between a first pivot bearing 24 and a second pivot bearing 25. The races 21", 23" bear against the hub carrier 11, while the annular rubber seals 21', 23' bear against the wheel head 12. The first pivot bearing 24 and the second pivot bearing 25 support the wheel head 12 rotatably on the hub carrier 11.

[0060] Fig. 2b shows, by way of example and schematically, a cross-section through another partial section of Fig. 1 . In this case, the first air duct 20 can be seen, which is formed as a bore 20 in the hub carrier 11. The diameter of the bore 20 is, for example, again 6 mm.

[0061] As can be seen, the first air duct 20 has an opening to the first rotary union 21 so that compressed air can flow from the first air duct 20 in the hub carrier 11 through the first rotary union 21 into the first air duct 20 in the wheel head 12.

[0062] Fig. 3a shows, by way of example and schematically, a cross-section through another section of Fig. 1. It shows the second air duct 22, which is formed as a bore 22 in the wheel head 12. The diameter of the bore 22 is, for example, 6 mm.

[0063] The second air channel 22 is designed, for example, to provide the common valve 30 with air pressure so that the common valve 30 opens and compressed air can be supplied to the vehicle tire via the first air channel 20 or compressed air can be released from the vehicle tire.

[0064] The second air duct 22 runs from the hub carrier 11 via a second rotary union 23, consisting of a race 23" and an annular rubber seal 23', into the wheel head 12 and from the second tire connection 16 further via a compressed air line (not shown) to the common valve 30.

[0065] As can be seen, the second air duct 22 has an opening to the second rotary union 23 so that compressed air can flow from the second air duct 22 in the hub carrier 11 through the second rotary union 23 into the second air duct 22 in the wheel head 12.

[0066] Fig. 3b shows, by way of example and schematically, a cross-section through another partial section of Fig. 1 . In this case, the second air duct 22 can be seen, which is formed as a bore 22 in the hub carrier 11. The diameter of the bore 22 is, for example, again 6 mm.

[0067] As can be seen, the second air duct 22 has an opening to the second rotary union 23 so that compressed air can flow from the second air duct 22 in the hub carrier 11 through the second rotary union 23 into the second air duct 22 in the wheel head 12.

[0068] Fig. 4 shows, by way of example and schematically, a cross-section through yet another partial section of Fig. 1 . A third air duct 26 can be seen, which is designed as a bore 26 and, for example, also has a diameter of 6 mm. The third air duct 26 has an opening to an intermediate chamber 27, which is arranged axially between the first rotary feedthrough 21 and the second rotary feedthrough 23. In addition, the third air duct 26 has a pressure relief valve 28, which opens automatically when an air pressure prevails in the third air duct 26 that is a certain amount greater than the ambient atmospheric pressure.

[0069] This allows compressed air escaping from the first rotary union 21 and the second rotary union 23 into the intermediate chamber 27 to be released into the environment.

[0070] Fig. 5 shows, by way of example and schematically, a possible embodiment of a common valve 30, which is designed as an air pressure controllable valve 30.

[0071] The common valve 30 has a first port 31 for receiving a compressed air line, which connects the first port 31 to the first air channel 20. Likewise, the common valve 30 has a second port 32 for receiving a compressed air line, which connects the second port 32 to the second air channel 22.

[0072] A tappet 33 of the common valve 30 can block or open a passage from the first port 31 to the valve outlet 34 depending on its position in the common valve 30.

[0073] A return spring 35 exerts a restoring force on the plunger 33, so that in the rest position, i.e., when not pressurized, it blocks the passage. If sufficient air pressure is applied to the plunger 33 via the second port 32, it is forced from its rest position and opens the passage.

[0074] In this state, the common valve 30 is open, and compressed air can be pumped into the vehicle tire from the first air channel 20, or compressed air can be released from the vehicle tire. For example, the common valve 30 is arranged directly on the vehicle tire instead of a conventional tire valve.

[0075] Reference symbol

[0076] Tire pressure control device

[0077] Hub carrier, joint housing

[0078] Wheel head first connection second connection first tire connection second tire connection first air duct, bore first rotary union ' annular circumferential rubber seal" race ring second air duct, bore second rotary union ' annular circumferential rubber seal" race ring first pivot bearing second pivot bearing third air duct, bore

[0079] Intermediate chamber

[0080] Pressure relief valve common valve first port second port

[0081] pestle

[0082] Valve outlet

[0083] Return spring

Claims

Patent claims 1. Tire pressure control device (10), comprising a hub carrier (11) and a wheel head (12) rotatably mounted on the hub carrier (11), wherein a first air duct (20) runs through the hub carrier (11), through a first rotary feedthrough (21) and through the wheel head (12) to a first tire connection (15) and wherein a second air duct (22) runs through the hub carrier (11), through a second rotary feedthrough (23) and through the wheel head (12) to a second tire connection (16), characterized in that the first tire connection (15) and the second tire connection (16) run to a common valve (30) and that the common valve (30) is designed as an air pressure-controllable valve (30) which is closed in the unpressurized state.

2. Tire pressure control device (10) according to claim 1, characterized in that the common valve (30) comprises a return spring (35) which counteracts the application of air pressure.

3. Tire pressure control device (10) according to at least one of claims 1 and 2, characterized in that the second air channel (22) is designed to provide the common valve (30) with air pressure so that the common valve (30) opens.

4. Tire pressure control device (10) according to at least one of claims 1 to 3, characterized in that the first air channel (20) is designed to supply or discharge compressed air to a vehicle tire in accordance with a valve position of the common valve (30) and in accordance with an air pressure in the first air channel (20).

5. Tire pressure control device (10) according to at least one of claims 1 to 4, characterized in that the first air channel (20) has a valve-controlled air outlet through which compressed air released from the vehicle tire can be released from the first air channel (20).

6. Tire pressure control device (10) according to at least one of claims 1 to 5, characterized in that the first air channel (20) in the hub carrier (11) and in the wheel head (12) has an identical diameter.

7. Tire pressure control device (10) according to at least one of claims 1 to 6, characterized in that the first rotary feedthrough (21) and the second rotary feedthrough (23) are arranged axially between a first rotary bearing (24) and a second rotary bearing (25), wherein the first rotary bearing (24) and the second rotary bearing (25) rotatably support the wheel head (11) on the hub carrier (12).

8. Tire pressure control device (10) according to at least one of claims 1 to 7, characterized in that the tire pressure control device (10) further comprises a third air channel (26) and that an intermediate chamber (27) is provided axially between the first rotary feedthrough (21) and the second rotary feedthrough (23), wherein the intermediate chamber (27) is connected to the third air channel (26), which connects the intermediate chamber (27) to an atmospheric ambient pressure.

9. Tire pressure control device (10) according to at least one of claims 1 to 8, characterized in that the tire pressure control device (10) further comprises a compressed air source.

10. Tire pressure control device (10) according to at least one of claims 1 to 9, characterized in that the hub carrier (11) is designed as a joint housing (11). 1 1. Agricultural utility vehicle comprising a tire pressure control device (10) according to at least one of claims 1 to 10.

12. Construction machine comprising a tire pressure control device (10) according to at least one of claims 1 to 10.

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