Rotary transmission device for transmitting control and / or working pressures to a fluid channel located or formed at least partially inside a shaft

Abstract

Rotary transmission device (1) for transmitting control and / or working pressures to a fluid channel (51) that is at least partially located or formed inside a shaft (50), in particular a drive shaft, wherein the rotary transmission device (1) has a stator assembly (2) arranged in a position fixed relative to a rotational movement of the shaft (50) with at least one fluid inlet / outlet (3) and a control element (4) that is displaceable in the longitudinal direction (L) of the shaft (50) between a first position and a second position, wherein a fluid space (5) is formed between the control element (4) and the outer surface of the shaft (50), wherein the stator assembly (2) has a sealing arrangement associated with the control element (4) with at least one seal (7, 8) in the form of a sealing lip, wherein the at least one seal (7, 8) and / or a topology of the outer surface of the shaft (50) in the area of ​​the stator assembly (2) are / are designed such thatthat with reference to the shaft (50) in the first position of the control element (4) the at least one seal (7, 8) is non-contacting and in the second position of the control element (4) is contacting and sealing.

Description

[0001] The present invention relates generally to a system for transmitting control and / or working pressures or pressurized media, particularly in the case of a drive shaft with a rotatably mounted vehicle tire. According to embodiments of the invention, it relates in particular to a rotary transmission device for transmitting control and / or working pressures or pressurized media to a fluid channel that is at least partially located or formed inside a shaft, in particular a drive shaft.

[0002] According to a further aspect, the invention relates to a system with such a rotary transmission device and a shaft on which the rotary transmission device is mounted, wherein the shaft is in particular designed as a drive shaft of a vehicle.

[0003] Furthermore, the invention relates to a tire pressure adjustment system for at least one wheel of an air-tired wheeled vehicle which is driven in rotation relative to a vehicle body and has at least one drive shaft for driving the wheel, wherein a fluid channel is received or formed inside the drive shaft, and wherein at least one rotary transmission device is provided for supplying and / or diverting a pressurized fluid to or from the fluid channel received or formed in the drive shaft as required.

[0004] German patent application DE 195 25 343 C2 relates to a device for supplying fluid from a first machine part to a second machine part, which is rotatable relative to the first machine part. The first machine part has a first conical contact surface that is rotationally symmetrical about the axis of the relative rotation. The second machine part has a complementary second conical contact surface that is rotationally symmetrical about the same axis. Transfer openings or transfer channels are formed in the contact surfaces and machine parts, with the contact surfaces engaging directly or via sealing elements arranged between them for fluid transfer.

[0005] Publication US 2 600 102 A relates to another rotary transmission device for transmitting control and / or working pressures.

[0006] German patent application DE 103 27 650 A1 relates to an axle assembly with a stationary axle housing, a rotating axle body mounted in the axle housing, and a first chamber surrounding the axle body, wherein the first chamber has a boundary wall rotating with the axle body and a rotary feedthrough. To enable a switchable rotary feedthrough for inflating a tire, the rotary feedthrough is designed with a ring fixed concentrically to the axle body and an annular disk extending radially beyond the ring and concentrically overlapping the ring.

[0007] German patent application DE 10 2004 021 161 A1 relates to a rotary feedthrough for a tire pressure control system. An axial annular gap exists between an axle-side annular surface and a hub-side annular surface. This gap communicates with a wheel-side air duct via an opening in the hub-side annular surface and with a vehicle-side air duct via an opening in the axle-side annular surface. This annular gap can be sealed off to the outside by switchable sealing rings arranged on radial slots that extend the axial annular gap at its ends.

[0008] The publication EP 2 826 644 B1 relates to a connector for transferring a fluid from an inlet channel to an outlet channel, which can rotate in relation to the inlet channel.

[0009] The publication DE 10 2013 105 890 A1 concerns a rotary feedthrough for a compressed air supply system between a stator and a rotor rotating relative to it.

[0010] The (subsequently published) document DE 10 2018 130 307 A1 relates to a further rotary transmission device for transmitting control and / or working pressures to a wheel hub or a vehicle rim received by the wheel hub.

[0011] Vehicle tires are typically filled with compressed air. Filling with other pressurized media is also conceivable, for example, with nitrogen. Vehicle tires within the meaning of this disclosure can be, for example, tube-type or tubeless tires. Vehicle tires are used, for example, in passenger cars, buses, commercial vehicles, and also, by way of example, in aircraft.

[0012] Conventional vehicle tires are typically supplied with a pressure medium, such as compressed air or nitrogen, via external connections. Standardized valves are usually used for this purpose. Vehicle tires typically have an optimal operating pressure, which depends on the specific application and operating conditions. For example, for land vehicles such as cars, buses, and trucks, there are operating pressures or pressure ranges that aim to ensure an optimal balance between rolling resistance, lateral grip, longitudinal stability, heat generation, and / or wear characteristics.

[0013] The actual pressure in a tire can fluctuate within certain limits, for example, depending on the ambient or operating temperature. Furthermore, a certain amount of pressure loss, such as a so-called gradual pressure loss, is often unavoidable over time. Systems exist for vehicles that allow monitoring of the operating or inflation pressure in tires. These can be either active or passive systems. Passive systems, for example, can be designed to determine and compare the rolling circumferences of the tires on an axle. If significant differences are found, this indicates pressure differences in the respective tires. Active systems for measuring and / or monitoring tire pressure typically include pressure sensors integrated into a wheel assembly.Such pressure sensors can, for example, be designed to transmit corresponding pressure signals wirelessly or via cable from the (rotating) tire to stationary components of the vehicle.

[0014] Furthermore, systems are known that allow for the autonomous adjustment of tire pressure. Such systems are found, for example, in off-road vehicles, military vehicles, or similar specialized vehicles. These systems can be designed to allow pressure adjustment while the vehicle is stationary, i.e., when the vehicle is not moving.

[0015] Known systems for autonomous tire pressure control in vehicles have a centralized structure. In other words, there is only one device for supplying the compressed air for inflating the tires. It is also conceivable to have a few compressed air supply devices, for example, in a combination of a tractor unit and a trailer or semi-trailer. However, such a central compressed air supply unit is designed to inflate multiple wheel units, particularly those on different axles or shafts. For this purpose, the central compressed air supply unit must be connected to multiple wheel units. Typically, the supply unit is mounted on the chassis, body, or superstructure of the vehicle. The supply unit can, for example, include a compressor or compressed air compressor.Starting from the supply unit, it is now necessary to lay a number of compressed air lines or hydraulic fluid lines to the individual wheel units. This typically requires the installation of multiple rotary unions for the hydraulic fluid lines. This is because the tires of the wheel units are usually mounted to the vehicle's axles in a way that allows them to rotate.

[0016] Unlike rotary transmission devices used to transfer control and / or working pressures or corresponding pressurized media from a stationary axle to a wheel unit rotating relative to the axle, rotary transmission devices for transferring control and / or working pressures or pressurized media to a rotating shaft, particularly a drive shaft, of a vehicle present particular challenges because, as a rule, only a very small installation space is available for accommodating or integrating such rotary transmission devices. This is especially true for drive shafts equipped with a ball joint to compensate for movements corresponding to steering inputs.

[0017] A rotary union for transmitting control and / or working pressures, or for transmitting pressurized media, typically comprises a stator ring and a rotor ring, which are installed in a ring-like configuration, for example, outside the axle housing. A rotary union inside the axle housing has so far been associated with high manufacturing costs and considerable risks. This applies, for example, to all-wheel-drive vehicles with external planetary gearboxes. Failure of the rotary union inside the axle housing would lead to air ingress into the axle housing, and the axle gearbox oil could leak from the gearbox breather.

[0018] To increase the service life of rotary unions and the operational reliability of tire pressure control systems, tire pressure control systems are increasingly being equipped with special switching valves on the wheels. These valves only subject the rotary unions to air pressure during the adjustment process. Nevertheless, the service life of rotary unions with larger diameters and conventional seals is still very critical, as frictional torques increase significantly with increasing diameters, in addition to sliding speeds.

[0019] Against this background, the invention is based on the objective of further developing a rotary transmission device of the type mentioned above, i.e., a rotary transmission device for transmitting control and / or working pressures or for transmitting pressurized media to a fluid channel that is at least partially located or formed inside a shaft, in particular a drive shaft, in such a way that it is characterized by high robustness and has as little impact as possible on the vehicle when not in use. Furthermore, the rotary transmission device should be characterized by low wear and a long service life.

[0020] This problem is solved according to the invention by a rotary transmission device according to the subject matter of independent claim 1, wherein advantageous embodiments thereof are specified in the corresponding dependent claims.

[0021] Accordingly, the invention relates to a rotary transmission device for transmitting control and / or working pressures or corresponding pressurized media to a fluid channel that is at least partially located inside a shaft, in particular a drive shaft, wherein the rotary transmission device has a stator assembly arranged in a position fixed relative to a rotational movement of the shaft, with at least one fluid inlet / outlet and a control element that is displaceable in the longitudinal direction of the shaft relative to the shaft between a first position and a second position, wherein a fluid space, in particular designed as an annular space, is formed between the control element and the outer surface of the shaft.In the rotary transmission device according to the second aspect of the invention, it is particularly provided that the stator assembly has a sealing arrangement associated with the control element, with at least one seal, in particular in the form of a sealing lip, wherein the at least one seal and / or a topology (surface condition or surface shaping) of the cylindrical surface of the shaft in the area of ​​the stator assembly are designed such that, with respect to the shaft, the at least one seal is at least substantially non-contacting in the first position of the control element (with respect to the shaft) and is in contact with the shaft and at least substantially sealing in the second position of the control element.

[0022] The rotary transmission device according to the invention is characterized by its small installation space on the one hand and its increased service life on the other. In particular, it is provided that when the rotary transmission device is not in use, the control element or the at least one seal of the sealing arrangement associated with the control element does not come into contact with the drive shaft rotating or rotatable relative to the stator assembly and is therefore not subject to wear.

[0023] Preferably, in the rotary transmission device according to the invention, a fluid space is formed between the control element and the outer surface of the shaft, which is advantageously designed in particular as an annular space arranged or designed coaxially to the shaft.

[0024] According to an embodiment of the rotary transmission device according to the invention, which is characterized in particular by its compact design, it is provided that a fluid channel is formed in the control element, which, at least in the second position of the control element, connects the at least one fluid supply / outlet of the stator assembly with the fluid space, which is designed in particular as an annular space, preferably permanently.

[0025] Furthermore, in this context it is advantageous that at least one branch channel is formed in the shaft, which connects the fluid channel received or formed inside the shaft with the fluid space of the stator assembly, which is designed in particular as an annular space.

[0026] In this context, it is advantageous if the stator assembly as a whole is designed to be at least substantially rotationally symmetrical, with the control element of the stator assembly being designed, in particular, as a control ring coaxial to the longitudinal axis of the shaft, which encloses a portion of the shaft in a sleeve-like manner. The control element, especially when designed as a control ring coaxial to the longitudinal axis of the shaft, can have a guide surface that interacts with a guide surface of a housing of the stator assembly, so that the control element is mounted in a guided manner, allowing it to be displaceably between the first and second positions relative to the housing of the stator assembly and relative to the shaft in the longitudinal direction of the shaft axis.

[0027] According to preferred embodiments of the rotary transmission device according to the invention, in the region of the stator assembly or in the region of the fluid chamber formed by the stator assembly or the control element of the stator assembly, the outer surface of the shaft has a conical area tapering with respect to the longitudinal axis of the shaft, wherein, when the control element is moved towards its first position, the at least one seal associated with the control element is moved together with the control element in the direction of the tapered area. Here, the term "direction of the tapered area" means the direction in which the diameter of the shaft tapers conically.

[0028] According to embodiments of the rotary transmission device according to the invention, it is particularly provided that the control element has a front end region viewed in the longitudinal direction of the shaft and an opposite rear end region, wherein a first seal, in particular in the form of a sealing lip, is assigned to the front end region and a second seal, in particular in the form of a sealing lip, is assigned to the rear end region, wherein the first and second seals are connected to the control element in such a way that they are moved along with the control element when the control element is moved longitudinally relative to the shaft, and wherein in the second position of the control element the seals seal the fluid space, which is in particular designed as an annular space, against the outer surface of the shaft, whereas in the first position of the control element the seals are in contact with the outer surface of the shaft.

[0029] According to further developments of the aforementioned embodiment of the rotary transmission device according to the invention, the outer surface of the shaft in the area of ​​the fluid chamber or in the area of ​​the stator assembly can have a first area that tapers conically with respect to the longitudinal axis of the shaft, which is associated with the first seal of the control element, and a second area that tapers conically with respect to the longitudinal axis of the shaft, which is associated with the second seal of the control element, wherein the direction of the taper of the first and second conical areas of the outer surface of the shaft corresponds to the direction in which the control element moves when it is moved in the direction of its first position.

[0030] However, the present invention is not limited to embodiments in which the lateral surface of the shaft has at least one conically tapered area with respect to the longitudinal axis of the shaft in the area of ​​the fluid space or in the area of ​​the stator assembly.Rather, alternatively or additionally to such a conically tapered area of ​​the shaft, it is conceivable that in the area of ​​the stator assembly the shaft's outer surface has at least one radially projecting area with respect to the longitudinal axis of the shaft and at least one radially recessed area with respect to the longitudinal axis of the shaft, wherein the at least one seal and / or the at least one radially projecting area of ​​the shaft's outer surface are designed such that in the second position of the control element the at least one seal contacts the at least one projecting area, and that in the first position of the control element the at least one seal is provided at the radially recessed area and preferably an air gap is provided between the at least one seal and the outer surface of the shaft.

[0031] For example, the shaft's outer surface in the fluid space can have a first section associated with the first seal and a second section associated with the second seal, wherein the first and second sections each have a radially projecting and a radially recessed area with respect to the shaft's longitudinal axis, and wherein the first and second seals are arranged in the first position of the control element at the recessed area of ​​the respective outer surface section of the shaft and in the second position of the control element at the radially projecting area of ​​the respective outer surface section of the shaft.

[0032] According to embodiments of the rotary transmission device according to the invention, the at least one fluid supply / outlet of the stator assembly is fluidly connected to a control chamber which is at least partially limited by the control element and which is designed such that, when the control chamber is pressurized (sufficiently), the control element can be moved into its second position.

[0033] In this context, it is conceivable that the control chamber, which is fluidically connected to the at least one fluid supply / outlet, is fluidically connected via a fluid channel formed in the control element to the fluid chamber (annular space) formed between the control element and the shaft's outer surface. In this embodiment, the pressurized medium, which is to be supplied to the fluid channel formed or contained in the shaft, can thus also be used simultaneously as the control medium for manipulating the control element.

[0034] Furthermore, a control line is provided, fluidically connected to a further (second) control chamber, which is separate from the at least one fluid supply / outlet. The further (second) control chamber is at least partially delimited by the control element of the stator assembly and is designed such that, when pressurized, the control element can be moved back to its first position. Alternatively or additionally to such a further (second) control chamber, it is also conceivable that the control element is pre-tensioned to its first position by a pre-tensioning element, in particular a spring.

[0035] In further developments of the rotary transmission device according to the invention, it is provided that in the first position of the control element a flow-related connection between the at least one fluid supply / discharge and the fluid channel is interrupted and in the second position of the control element a flow-related connection between the at least one fluid supply / discharge and the fluid channel is established.

[0036] The stator assembly can have a sealing arrangement associated with the control element, comprising at least one seal, in particular in the form of a sealing lip, wherein the at least one seal and / or a topology, i.e., surface configuration or shaping, of the shaft's outer surface in the area of ​​the stator assembly are designed such that, with respect to the shaft, the at least one seal is at least substantially non-contacting in the first position of the control element and is in contact with the shaft and sealing at least substantially in the second position of the control element.

[0037] The invention further relates to a system with a rotary transmission device of the type described above, wherein the system further comprises a shaft on which the rotary transmission device is mounted, the shaft being in particular designed as a drive shaft of a vehicle. The invention further relates to a tire pressure adjustment system for at least one wheel of a pneumatic-tired wheeled vehicle, which is driven to rotate relative to a vehicle body, with at least one drive shaft for driving the wheel, wherein a fluid channel is received or formed inside the drive shaft, and wherein at least one rotary transmission device of the type described above is provided for supplying and / or discharging a pressurized fluid to and / or from the fluid channel received or formed inside the drive shaft as required.

[0038] The following describes in more detail an embodiment of a system with an exemplary design of the rotary transmission device according to the invention, with reference to the accompanying drawings.

[0039] They show: Fig. 1. Schematic and in a top view, an exemplary embodiment of a drive shaft (complete) of a wheel drive for a steered and driven vehicle wheel; Fig. 2a schematically a sectional view along line AA in Fig. 1 of the exemplary embodiment of the drive shaft, wherein a rotary transmission device associated with the drive shaft is in its first operating state, in which no pressurized medium is transmitted to the drive shaft; Fig. 2b schematically a sectional view along line BB in Fig. 2a; Fig. 3 schematically a detailed view from Fig. 2b; Fig. 4a schematically a sectional view through an exemplary embodiment of a drive shaft with a rotary transmission device in its first operating state, in which no pressurized medium is transmitted to the drive shaft; Fig. 4b schematically a detailed view of an area of ​​the rotary transmission device according to Fig. 4a; Fig. 4c schematically a detailed view from Fig. 4b; Fig. 5a schematically a sectional view of the drive shaft according to Fig. 4a with the rotary transmission device in a second operating state in which a pressurized medium can be transmitted to the drive shaft; Fig. 5b schematically a detailed view of the rotary transmission device according to Fig. 5a; and Fig. 5c schematically a detailed view of the Fig. 5b.

[0040] The following refers to the descriptions in the Fig. 1 and Fig. 2a, b first describe an exemplary embodiment of a drive shaft 50, which is provided with an embodiment of the rotary transmission device 1 according to the invention. Here, in Fig. 2a and in Fig. 2b The rotary transmission device 1 is shown in its first operating state, in which no pressurized medium is transmitted via the rotary transmission device 1 to a fluid channel 51 received or formed in the drive shaft 50. The second operating state of the rotary transmission device 1, in which a pressurized medium can be transmitted via the rotary transmission device 1 to the fluid channel 51 received or formed inside the drive shaft 50, is subsequently described with reference to the illustrations in the Fig. 5a, Fig. 5b and Fig. 5c described.

[0041] As in Fig. 1 and Fig. 2a and Fig. As shown in Figure 2b, the drive shaft 50 is, for example, a drive shaft 50 of a wheel drive for a steered and driven vehicle wheel 54. The drive shaft 50 has a first, wheel-side shaft 53, a universal joint 52, and a second, axle-side shaft. Since the steering axis of the wheel must be as close as possible to the wheel plane in such a drive shaft 50 to minimize the steering scrub radius, there is a certain space constraint with regard to the rotary transmission device 1. Therefore, in particular, it is necessary to provide a particularly compact rotary transmission device 1 for such drive shafts for a steered and driven vehicle wheel 54, which is designed to be as wear-free as possible.

[0042] The rotary transmission device 1, as it is combined with the drive shaft 50 in Fig. 2a and Fig. The component shown in 2b can, in particular, be part of a tire pressure control system of a motor vehicle.

[0043] The in Fig. 2a and Fig. 2b The rotary transmission device 1, shown schematically, is mounted on the drive shaft 50 and, in particular, connected to it in a torque-locking manner. Although not shown, the drive shaft 50 can be enclosed on the vehicle side by an axle housing. The axle housing can, at least partially, form the housing 12 of a stator assembly 2 of the rotary transmission device 1.

[0044] The free section of the drive shaft 50, i.e. the wheel-side end region of the drive shaft 50, is connected to the wheel unit 54 via the aforementioned cardan joint 52 and thus serves, in a figurative sense, to attach one or more wheels to the drive shaft 50 so that they can be driven by the drive shaft 50.

[0045] The construction and operation of the rotary transmission device 1 are described below with reference to the illustrations in Fig. 4a to Fig. 4c and Fig. 5a to Fig. 5c is described in more detail.

[0046] In detail, in Fig. 4a and Fig. Figure 4b shows an exemplary embodiment of the rotary transmission device 1 according to the invention in its first operating state, in which no pressurized medium or control and / or working pressures are transmitted via the rotary transmission device 1 to a fluid channel 51 received or formed in the drive shaft 50. However, in particular, Fig. 5a and Fig. 5b shows the exemplary embodiment of the rotary transmission device 1 according to the invention in its second operating state, in which a transmission of control and / or working pressures or a transmission of a pressurized medium via the rotary transmission device 1 to the fluid channel 51 received or formed inside the drive shaft 50 is possible.

[0047] As shown in the drawings, in the exemplary embodiment of the rotary transmission device 1, a stator assembly 2 is arranged in a fixed position relative to the rotational movement of the drive shaft 50. The stator assembly 2 comprises a housing 12 (cage structure), which may, for example, be connected to an axle housing (not shown in the drawings).

[0048] The stator assembly 2, which is fixed in position relative to the rotational movement of the drive shaft 50, has a connection (fluid supply / outlet 3) through which a pressurized medium can be supplied to the stator assembly 2 as required. Naturally, it is possible to provide several different fluid supply / outlet connections, particularly in the housing 12 of the stator assembly 2. Other embodiments for coupling control and / or operating pressures or pressurized media into the housing 12 of the stator assembly 2 are also possible.

[0049] As can be seen in particular from the detailed views according to Fig. 4b and Fig. 5b, in addition to the fluid supply / exhaust 3, a connection for a control line 11 is provided on the stator assembly 2.

[0050] The stator assembly 2 has a control element 4, which, in the exemplary embodiment of the rotary transmission device 1 according to the invention shown in the drawings, is designed as a control ring coaxial to the longitudinal axis L of the shaft. This control element 4 (control ring) is, in particular, at least partially, mounted in the housing 12 of the stator assembly 2 so as to be displaceable in the longitudinal direction L of the shaft. Specifically, the control element 4 is mounted between a Fig. 5b shown first position and one in Fig. 4b shown second position relative to the drive shaft 50 (and also relative to the housing 12 of the stator assembly 2) is slidably mounted.

[0051] Although not provided for in the embodiment shown in the drawings, the control element 4 can be designed such that in the first position of the control element (cf. Fig. 5b) a flow-related connection between the fluid supply / discharge 3 and the fluid channel 51 received or formed inside the drive shaft 50 is interrupted, while in the second position of the control element (cf. Fig. 5b) a flow connection is established between the fluid supply / discharge 3 and the fluid channel 51 received or formed in the drive shaft 50.

[0052] As the depictions in Fig. 4b and Fig. 5b and in the corresponding detailed views according to Fig. 4c and Fig. As can be seen from Figure 5c, the stator assembly 2 further comprises a sealing arrangement associated with the control element 4, with at least one seal 7, 8, in particular in the form of a sealing lip, wherein the at least one seal 7, 8 and / or a topology of the outer surface of the drive shaft 50 in the area of ​​the stator assembly 2 are designed such that, with reference to the drive shaft 50, the at least one seal 7, 8 is in the first position of the control element (see Figure 5c). Fig. 4b and Fig. 4c) the at least one seal 7, 8 is at least substantially non-contacting with respect to the cylindrical surface of the drive shaft 50, wherein in the second position of the control element (cf. Fig. 5b and Fig. 5c) which is at least one seal 7, 8 contacting with respect to the drive shaft 50 and sealing at least substantially.

[0053] In detail, the rotary transmission device 1 shown in the drawings is provided that the control element 4 has a front end region and an opposite rear end region, viewed in the longitudinal direction L of the shaft. A first seal 7, in particular in the form of a sealing lip, is assigned to the front end region, and a second seal 8, in particular in the form of a sealing lip, is assigned to the rear end region. The first and second seals 7, 8 are connected to the control element 4 in such a way that they move with the control element 4 when the control element is longitudinally displaced relative to the drive shaft 50. In the second position of the control element (see drawing 1), the control element is in the front end region. Fig. 5b and Fig. 5c) The seals 7, 8 seal a fluid space 5, designed in particular as an annular space between the control element 4 and the outer surface of the drive shaft 50, against the outer surface of the drive shaft 50, whereas in the first position of the control element (cf. Fig. 4b and Fig. 4c) the seals 7, 8 are non-contact or at least substantially non-contact with respect to the outer surface of the drive shaft 50.

[0054] The detailed views in Fig. 4b and in Fig. 5b further indicates that the control element 4, which is designed in particular as a control ring designed coaxial to the longitudinal axis L of the shaft, has a guide surface that interacts with a guide surface of the housing of the stator assembly 2, so that the control element 4 is mounted in a guided manner between the first and second positions relative to the housing 12 of the stator assembly 2 and relative to the drive shaft 50 in the longitudinal direction of the longitudinal axis L of the shaft.

[0055] Furthermore, according to the detailed views Fig. 4b and Fig. It can be seen from 5b that a fluid space 5, in particular annular, is formed between the control element 4 and the outer surface of the drive shaft 50, wherein at least one fluid channel 6 is formed in the control element 4, which is at least in the second position of the control element 4 (cf. Fig. 5b) connects the fluid supply / discharge 3 of the stator assembly 2 in terms of flow with the fluid space 5, which is designed in particular as an annular space.

[0056] The detailed views in Fig. 4c and Fig. It can be seen from 5c that the outer surface of the drive shaft 50 in the area of ​​the fluid space 5 has at least one conical area 56, 57 with reference to the longitudinal axis L of the shaft, wherein when the control element 4 is moved in the direction of its first position the at least one seal 7, 8 is moved in the direction of the conical area 56, 57.

[0057] In detail, according to the views Fig. 4b and Fig.5b shows in particular that the outer surface of the drive shaft 50 in the area of ​​the fluid chamber 5 has a first region 56, which tapers conically with respect to the longitudinal axis L of the shaft and is associated with the first seal 7, and a second region 57, which tapers conically with respect to the longitudinal axis L of the shaft and is associated with the second seal 8. The direction of taper of the first and second conical regions 56, 57 corresponds to the direction in which the control element 4 moves when it is moved towards its first position.

[0058] However, the invention is not limited to embodiments in which the topology of the lateral surface of the drive shaft 50 has corresponding conically tapered areas 56, 57, as shown by way of example in the drawings.Rather, it is fundamentally conceivable that the cylindrical surface of the drive shaft 50 in the area of ​​the fluid space 5 has a first section associated with the first seal 7 and a second section associated with the second seal 8, wherein the first and second sections each have a region radially projecting with respect to the longitudinal axis L of the shaft and a region radially recessed with respect to the longitudinal axis L of the shaft, wherein the first and second seals 7, 8 are arranged in the first position of the control element 4 at the recessed region of the respective cylindrical surface section of the drive shaft 50 and in the second position of the control element 4 at the projecting region of the respective cylindrical surface section of the drive shaft 50.

[0059] As already indicated, the fluid supply / exhaust 3 of the stator assembly 2 is fluidically connected to a control chamber 9 which is at least partially limited by the control element 4 and which is designed in such a way that when the control chamber 9 is pressurized, the control element 4 can be moved into its second position.

[0060] Furthermore, in the exemplary embodiment of the rotary transmission device 1 according to the invention shown in the drawings, a further control line 11 is used, which is fluidly connected to a further (second) control chamber 10, wherein this further (second) control chamber 10 is at least partially limited by the control element 4 and is designed such that when the further (second) control chamber 10 is pressurized, the control element 4 can be moved into its first position.

[0061] In the exemplary embodiment shown in the drawings, the control chamber 9 (first control chamber) which is fluidically connected to the fluid chamber 5 formed between the control element 4 and the outer surface of the drive shaft 50 is fluidically connected via a fluid channel 51 formed in the control element 4.

[0062] In short, the exemplary embodiment of the rotary transmission device 1 according to the invention, as shown in the drawings, can be characterized as follows: In order to minimize wear and friction losses during the operation of the rotary transmission device 1, the rotary transmission device 1 is designed such that the corresponding sealing elements 7, 8 (sealing lips) of the sealing arrangement assigned to the control element 4 only engage or come into contact with the drive shaft 50 rotating relative to the stator assembly 2 for the period of time during which the pressurized medium is transmitted to the fluid channel 51 formed in the drive shaft 50.

[0063] The drive shaft 50, which is designed, for example, as a hollow or partially hollow shaft, can have any number of channels. Each fluid channel of the drive shaft 50, running parallel to the axis of rotation of the drive shaft 50, has any number of branch channels to the drive shaft surface, with all branch channels located in the area of ​​the stator assembly 2 experiencing the same control pressure. The outer contour (topology) of the drive shaft 50 is designed such that the drive shaft 50 has sealing sections in the transmission area with respect to the axis of rotation. A sealing section is a section on the longitudinal axis of the drive shaft 50 bounded by two seals 7, 8, in particular sealing lips, or by rotationally symmetrical material accumulations.

[0064] The described embodiment relates to a two-channel rotary feedthrough, comprising a working channel and a control channel. This can also be implemented as a single-channel design or with more than two channels.

[0065] The description of the invention makes it clear that the rotary transmission device 1 according to the invention is particularly suitable for retrofitting.

[0066] The invention is not limited to the embodiment shown in the drawings, but results from a combination of all the features disclosed herein. Reference symbol list 1 Rotary transmission device 2 Stator assembly 3 Fluid inlet / outlet 4 Control element / control ring 5 Fluid space, especially one shaped as an annular space 6 Fluid channel in the control element 7 first seal 8 second seal 9 first control room 10 second control room 11 Control line 12 Stator assembly housings 50 Drive shaft 51 Fluid channel inside the drive shaft 52 Cardan joint 53 wheel-side shaft 54 vehicle wheel 55 branch canal 56 first conical area 57 second conical area L Wave longitudinal direction

Claims

[1] Rotary transmission device (1) for transmitting control and / or working pressures to a fluid channel (51) that is received or formed at least partially inside a shaft (50), in particular a drive shaft, wherein the rotary transmission device (1) has a stator assembly (2) arranged in a position fixed relative to a rotational movement of the shaft (50) with at least one fluid inlet / outlet (3) and a control element (4) that is displaceable in the longitudinal direction (L) of the shaft (50) between a first position and a second position, wherein a fluid space (5) is formed between the control element (4) and the outer surface of the shaft (50), wherein the stator assembly (2) has a sealing arrangement associated with the control element (4) with at least one seal (7, 8) in the form of a sealing lip, wherein the at least one seal (7,8) and / or a topology of the lateral surface of the shaft (50) in the area of ​​the stator assembly (2) is designed such that, with reference to the shaft (50), in the first position of the control element (4) the at least one seal (7, 8) is non-contacting and in the second position of the control element (4) is contacting and sealing. [2] Rotary transmission device (1) according to claim 1, wherein a fluid channel (6) is formed in the control element (4), which at least in the second position of the control element (4) connects the at least one fluid inlet / outlet (3) to the fluid space (5) in terms of flow. [3] Rotary transmission device (1) according to claim 1 or 2, wherein at least one branch channel (55) is formed in the shaft (50) which connects the fluid channel (51) received or formed inside the shaft (50) to the fluid space (5) in terms of flow. [4] Rotary transmission device (1) according to one of claims 1 to 3, wherein the control element (4) is designed as a control ring designed coaxial to the longitudinal axis of the shaft, which has a guide surface cooperating with a guide surface of a housing (12) of the stator assembly (2) and is mounted to be displaceable between the first and second positions relative to the housing (12) of the stator assembly (2) and relative to the shaft (50) in the longitudinal direction (L) of the longitudinal axis of the shaft. [5] Rotary transmission device (1) according to one of claims 1 to 4, wherein the outer surface of the shaft (50) in the area of ​​the fluid space (5) has at least one conically tapered area (56, 57) with respect to the longitudinal axis (L) of the shaft, wherein when the control element (4) is moved in the direction of its first position the at least one seal (7, 8) is moved along with it in the direction of the tapered area (56, 57). [6] Rotary transmission device (1) according to one of claims 1 to 5, wherein the control element (4) has a front end region viewed in the longitudinal direction (L) of the shaft and an opposite rear end region, wherein a first seal (7) in the form of a sealing lip is assigned to the front end region and a second seal (8) in the form of a sealing lip is assigned to the rear end region, wherein the first and second seals (7, 8) are connected to the control element (4) in such a way that they are moved along with the control element (4) when the control element (4) is moved longitudinally relative to the shaft (50), and wherein in the second position of the control element (4) the seals (7, 8) seal the fluid chamber (5) against the outer surface of the shaft (50), while in the first position of the control element (4) the seals (7, 8) are non-contacting with respect to the outer surface of the shaft (50). [7] Rotary transmission device (1) according to claim 6, wherein the outer surface of the shaft (50) in the region of the fluid space (5) has a first area (56) tapering conically with respect to the longitudinal axis (L) of the shaft, which is associated with the first seal (7), and a second area (57) tapering conically with respect to the longitudinal axis (L) of the shaft, which is associated with the second seal (8), wherein the taper direction of the first and second tapered areas (56, 57) each corresponds to the direction in which the control element (4) moves when it is moved in the direction of its first position. [8] Rotary transmission device (1) according to one of claims 1 to 7, wherein in the region of the stator assembly (2) the outer surface of the shaft (50) has at least one radially projecting area with respect to the longitudinal axis (L) of the shaft and at least one radially recessed area with respect to the longitudinal axis (L), wherein the at least one seal (7, 8) and / or the at least one radially projecting area of ​​the shaft outer surface are / are designed such that in the second position of the control element (4) the at least one seal (7, 8) contacts the at least one radially projecting area, and wherein the at least one seal (7, 8) and / or the at least one radially recessed area are / are designed such that in the first position of the control element (4) the at least one seal (7, 8) is located at the radially recessed area. [9] Rotary transmission device (1) according to claim 6, wherein the cylindrical surface of the shaft (50) in the region of the fluid space (5) formed between the control element (4) and the cylindrical surface of the shaft (50) has a first section associated with the first seal (7) and a second section associated with the second seal (8), wherein the first and second sections each have a radially projecting and a radially recessed area with respect to the longitudinal axis (L) of the shaft, wherein the first and second seals (7, 8) are arranged in the first position of the control element (4) at the radially recessed area of ​​the respective cylindrical surface section of the shaft (50) and in the second position of the control element (4) at the radially projecting area of ​​the respective cylindrical surface section of the shaft (50). [10] Rotary transmission device (1) according to one of claims 1 to 9, wherein the at least one fluid inlet / outlet (3) is fluidly connected to a control chamber (9) which is at least partially limited by the control element (4) and which is designed such that when the control chamber (9) is pressurized, the control element (4) can be moved into its second position, wherein a control line (11) is provided which is fluidly connected to a further control chamber (10), wherein the further control chamber (10) is at least partially limited by the control element (4) and is designed such that when the further control chamber (10) is pressurized, the control element (4) can be moved into its first position. [11] Rotary transmission device (1) according to claim 10, wherein the control chamber (9) which is fluidically connected to the at least one fluid supply / discharge (3) is fluidically connected to the fluid chamber (5) or to a fluid chamber (5) formed between the control element (4) and the outer surface of the shaft (50) via a fluid channel (6) formed in the control element (4). [12] Rotary transmission device (1) according to one of claims 1 to 11, wherein in the first position of the control element (4) a flow connection between the at least one fluid inlet / outlet (3) and the fluid channel (51) is interrupted and in the second position of the control element (4) a flow connection between the at least one fluid inlet / outlet (3) and the fluid channel (51) is established. [13] System comprising a rotary transmission device (1) according to any one of claims 1 to 12 and a shaft (50) on which the rotary transmission device (1) is mounted. [14] Tire pressure adjustment system for at least one wheel of a pneumatic-tired wheeled vehicle which is driven to rotate relative to a vehicle body, with at least one drive shaft (50) for driving the wheel, wherein a fluid channel (51) is received or formed inside the drive shaft, and wherein at least one rotary transmission device (1) according to one of claims 1 to 12 is provided for supplying and / or diverting a pressurized fluid to or from the fluid channel (51) as required.

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