WO2018035518A1 - Compressor assembly for supplying a pressure fluid to a tire - Google Patents

Compressor assembly for supplying a pressure fluid to a tire Download PDF

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Publication number
WO2018035518A1
WO2018035518A1 PCT/US2017/047772 US2017047772W WO2018035518A1 WO 2018035518 A1 WO2018035518 A1 WO 2018035518A1 US 2017047772 W US2017047772 W US 2017047772W WO 2018035518 A1 WO2018035518 A1 WO 2018035518A1
Authority
WO
WIPO (PCT)
Prior art keywords
compressor assembly
wheel suspension
hub
wheel
affixed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2017/047772
Other languages
French (fr)
Inventor
Martin P. SPINDLER
Konstantin Tsiberidis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
KT Projektentwicklungs GmbH
Illinois Tool Works Inc
Original Assignee
KT Projektentwicklungs GmbH
Illinois Tool Works Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE102016010055.9A external-priority patent/DE102016010055B3/en
Priority claimed from DE102016010054.0A external-priority patent/DE102016010054B4/en
Application filed by KT Projektentwicklungs GmbH, Illinois Tool Works Inc filed Critical KT Projektentwicklungs GmbH
Publication of WO2018035518A1 publication Critical patent/WO2018035518A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C23/00—Devices for measuring, signalling, controlling, or distributing tyre pressure or temperature, specially adapted for mounting on vehicles; Arrangement of tyre inflating devices on vehicles, e.g. of pumps or of tanks; Tyre cooling arrangements
    • B60C23/10—Arrangement of tyre-inflating pumps mounted on vehicles
    • B60C23/12—Arrangement of tyre-inflating pumps mounted on vehicles operated by a running wheel
    • B60C23/127—Arrangement of tyre-inflating pumps mounted on vehicles operated by a running wheel the pumps being mounted on the hubs

Definitions

  • the present invention generally relates to the field of tire pressure regulation and in particular, to a compressor assembly for supplying pressure fluid to a tire of a vehicle wheel that can be mounted on a wheel hub.
  • a pressure fluid such as compressed air
  • tire valves are usually placed in the region of a rim on which the tire is mounted so that they are easily accessible from the outside.
  • a pressure fluid source external to the vehicle can be connected to the tire valve, for example by means of a hose line, in order to manually check the tire pressure and correct it as needed.
  • Vehicle-mounted pressure fluid supply systems are also known, which make it possible to autonomously fill a vehicle tire with pressure fluid.
  • a central vehicle-mounted pressure fluid source such as a compressor or pressure reservoir
  • pressure fluid lines are routed to the wheels and are connected to the tire valves there.
  • rotary feedthroughs are provided, which make it possible to fill the tires with pressure fluid even while driving, i.e. when the wheels are turning. It is thus possible to adapt the tire pressure, for example to changing load conditions, road surfaces, and ambient temperatures.
  • the object of the invention is to disclose a solution which can autonomously fill a vehicle wheel with pressure fluid during driving and can be implemented in a simple and reliable way in terms of its design. l According to the invention, this object is attained by means of a compressor assembly for supplying pressure fluid to a tire of a vehicle wheel that can be mounted on a wheel hub, said wheel hub being supportable in rotary fashion on a wheel suspension that defines an axial direction.
  • the compressor assembly is distinguished by the fact that it defines at least one compression chamber and includes a drive that is equipped to produce a back-and-forth linear motion of a hub-mounted compressor component in the axial direction through a cooperation between the compressor component and a component affixed to the wheel suspension, the linear motion of the compressor component producing a change in the volume of the at least one compression chamber and thus pressurizing pressure fluid that is to be conveyed into the tire.
  • the invention can therefore relate to a system for supplying pressure fluid to a tire, comprising a vehicle wheel, a compressor assembly, and a wheel hub.
  • the at least one compression chamber of the compressor assembly is situated in the hub and - together with the wheel hub - is subjected to a rotary motion relative to the wheel suspension during driving.
  • the actual compression procedure therefore takes place in the hub and, when a vehicle wheel is mounted on the wheel hub, makes it possible to independently supply pressure fluid for the tire directly in the vehicle wheel and thus even during driving.
  • Hub-mounted components are understood to be those components that are directly or indirectly connected to the wheel hub so that when a rotary motion of the wheel hub occurs, they rotate along with the wheel hub relative to the wheel suspension.
  • the wheel suspension is affixed to the vehicle and can, for example, include a wheel mount or an axle stub of a vehicle axle. The fact that the linear motion of the compressor component occurs in the axial direction of the wheel suspension minimizes imbalances in the vehicle wheel resulting from an operation of the compressor assembly that occurs during driving.
  • the compressor assembly according to the invention can be used to implement a decentralized pressure fluid supply system in which each vehicle wheel has its own pressure fluid supply unit. It is thus possible to avoid the long distances of pressure fluid line that must be provided in the vehicle in the pressure fluid supply systems mentioned at the beginning. It is also possible to eliminate the rotary feedthroughs, whose reliability and long- term functionality are hard to achieve, at the transition from the vehicle chassis to the rotatable vehicle wheels.
  • the compressor assembly according to the invention makes it possible to achieve a fundamental change in known pressure fluid supply systems, moving away from a centralized
  • the compressor assembly drive that is required for the compression procedure is implemented through the cooperation of the hub-mounted compressor component with the component affixed to the wheel suspension.
  • the compressor component Since the compressor component is hub-mounted, it rotates around the wheel suspension with the wheel hub during driving.
  • the drive can include a transforming device, which produces the linear motion of the compressor component from a rotary motion of the compressor component when the wheel hub rotates around the wheel suspension.
  • the compressor assembly can include a preferably annular cylinder and the compressor component is a preferably annular piston that is accommodated in the cylinder so that the compression chamber is formed between the cylinder and the piston.
  • An annular cylinder can also be referred to as a ring cylinder and an annular piston can also be referred to as a ring piston.
  • Such a compressor assembly can then also be referred to as a ring piston compressor.
  • the ring cylinder and the ring piston can be embodied as rotationally symmetrical and can be arranged coaxially to each other around the longitudinal axis defined by the wheel suspension in order to minimize imbalances in the vehicle wheel caused by the compressor assembly during driving.
  • the compressor assembly can, for example, also have a cylindrical piston, which is accommodated in a cylindrical chamber.
  • a pressure fluid such as compressed air can be pressurized in the compression chamber and subsequently supplied to the tire via a short pressure fluid line.
  • a seal can be provided, which seals the piston against the cylinder.
  • the piston and/or the seal can also be provided with at least one pressure fluid inlet via which pressure fluid can travel into the compression chamber during an intake stroke of the piston.
  • a pressure fluid inlet can, for example, be provided with a reed valve, which allows the inlet of pressure fluid into the compression chamber during an intake stroke of the piston and closes during a compression stroke of the piston so that pressure fluid that is present in the compression chamber can be pressurized.
  • a ring piston is provided with a plurality of pressure fluid inlets, then these can be positioned so that they are distributed in the circumference direction around the ring piston or seal.
  • the cylinder can be provided with at least one pressure fluid outlet via which the pressure fluid that is pressurized during a compression stroke of the piston can be conveyed from the compression chamber into a pressure fluid line that leads to the tire.
  • the pressure fluid outlet can be provided with a check valve, which prevents pressurized pressure fluid from flowing out of the pressure fluid line and back into the compression chamber. If a ring cylinder is provided with a plurality of pressure fluid outlets, then these can be positioned so that they are distributed in the circumference direction around the ring cylinder.
  • the compressor assembly can be provided as a separate subassembly, which is independent of the wheel hub.
  • the cylinder can thus be embodied as a separates component, which, together with the other components of the compressor assembly, can be mounted as a subassembly to the wheel hub.
  • the cylinder can be embodied as a preferably annular recess in the wheel hub, for example on an inside or outside of the wheel hub. In this case, the wheel hub is a part of the compressor assembly.
  • the piston In order to produce the linear motion of the piston when the wheel hub rotates around the axis defined by the wheel suspension, the piston can have a sinusoidal circumferential groove extending around its circumference and the transforming device can have at least one engaging element, which can be affixed to the wheel suspension and engages in the sinusoidal circumferential groove in order, when the wheel hub rotates relative to the wheel suspension, to superimpose the linear motion of the piston on the rotary motion of the piston or - in other words - in order to impart the desired linear motion to the rotating piston.
  • the above-mentioned cooperation of the hub-mounted compressor with the component affixed to the wheel suspension is implemented between the at least one engaging element and the piston.
  • the at least one engaging element can be positioned in a preferably annular engaging element support, which in turn is positioned in a rotationally symmetrical around the longitudinal axis that is defined by the wheel suspension.
  • the sinusoidal circumferential groove can be positioned either on the outer circumference or the inner circumference.
  • the transforming device can also include a plurality of engaging elements that can be affixed to the wheel suspension, which are distributed around the circumference of the engaging element support and which engage in the sinusoidal circumferential groove of the piston.
  • the engaging elements can be spaced apart from one another along the groove by a whole sinusoidal oscillation (or possibly a multiple thereof). It is thus possible to assure a stable and accurately fitting guidance of the piston in the cylinder and to prevent the piston from tilting relative to the longitudinal axis.
  • the transforming device can include a clutch device by means of which on the one hand, the at least one engaging element can be engaged in order to produce a connection affixing the at least one engaging element to the wheel suspension and by means of which on the other hand, the at least one engaging element can be disengaged in order to release the connection affixing the at least one engaging element to the wheel suspension. If the at least one engaging element is disengaged, then it is able to rotate together with the piston - or the entire wheel hub - around the wheel suspension so that the linear motion is not superimposed with the rotary motion of the piston and as a result, the compressor assembly is not driven.
  • the clutch device can be electromagnetically actuated.
  • the clutch device can include a preferably annular clutch element affixed to the wheel suspension and a hub-mounted, preferably annular clutch element that is connected to the at least one engaging element; through the supply of energy to the clutch element affixed to the wheel suspension, an electromagnetic force, which acts between the hub-mounted clutch element and the clutch element affixed to the wheel suspension and presses the two clutch elements against each other in order to produce a non-positive connection between the at least one engaging element and the clutch element affixed to the wheel suspension.
  • the clutch device can be actuated in a pressure fluid-controlled way.
  • the clutch device can include a preferably annular engaging element affixed to the wheel suspension, a hub-mounted, preferably annular clutch element that is connected to the at least one engaging element, and a preferably annular bellows that cooperates with the hub- mounted clutch element or with the clutch element affixed to the wheel suspension; when in the inflated state, this bellows presses the two clutch elements against each other in order to produce a non-positive connection between the at least one engaging element and the clutch element affixed to the wheel suspension and when in the non-inflated state, it cancels the non-positive connection between the hub-mounted clutch element and the clutch element affixed to the wheel suspension.
  • the hub-mounted clutch element can be connected to the at least one engaging element via the engaging element support.
  • both the hub-mounted clutch element and the clutch element affixed to the wheel suspension can be embodied as rotationally symmetrical and coaxial to each other relative to the longitudinal axis of the wheel suspension.
  • annular engaging element support, bellows, or coupling element that is hub-mounted or affixed to the wheel suspension
  • a disk-shaped engaging element support, bellows, or coupling element that is hub-mounted or affixed to the wheel suspension.
  • the clutch element affixed to the wheel suspension can, for example, be attached to the wheel suspension by means of a radially extending axle stub cap that is fastened to an axle stub of a vehicle axle.
  • the bellows can be filled with pressure fluid from the tire of the vehicle wheel via a pressure fluid line.
  • a valve can be provided that is contacted by the pressure fluid from the tire, which fluid is at the tire pressure, and that, when the tire pressure falls below a threshold value, opens in order to fill the bellows with the pressure fluid and shift it into the inflated state.
  • the compressor assembly can include an electronic control unit, which sends appropriate switching signals to the valve.
  • the control unit can be connected to a tire pressure sensor for monitoring the tire pressure; then the tire pressure falls below the threshold value, the control unit emits a switching signal to open the valve.
  • Both the valve and the tire pressure sensor can be positioned in a central region around the longitudinal axis of the wheel suspension in order to minimize any imbalances of the vehicle wheel during driving.
  • the compressor assembly can have a generator device for generating electrical energy as the wheel hub rotates around the wheel suspension.
  • the generator device can include a hub- mounted rotor and, cooperating with it, a stator that is affixed to the wheel suspension.
  • An energy storage device can also be provided, which buffers electrical energy produced by the generator device in order to ensure a supply of electrical energy to the above-mentioned consumer components independently of the operation of the generator device.
  • the movement of the wheel hub relative to the wheel suspension is made use of in order to implement the drive of the compressor assembly.
  • the compression procedure for preparing pressure fluid for the tire can only take place during driving.
  • the cooperation of the hub- mounted compressor component with the component affixed to the wheel suspension can also be implemented in that the drive has an electromagnetic coil and the compressor component is an armature, which can be moved back and forth in the axial direction by an electromagnetic force generated by supplying energy to the coil.
  • the electromagnetic coil can be affixed to the wheel suspension and the armature can be positioned in the hub.
  • the compression procedure for supplying pressure fluid to the tire can also take place when the vehicle is at rest.
  • the electrical energy that is necessary in order to supply energy to the coil can, for example, be supplied by an energy source in the vehicle, for example the main battery of a vehicle. If the coil is affixed to the wheel suspension, then corresponding supply lines can easily be routed from the energy source to the coil.
  • the at least one compression chamber as described above for the first drive variant, can be formed by a preferably annular piston accommodated in a preferably annular cylinder; in this case, the linear motion of the piston is produced by the armature that is driven by the coil.
  • the piston can be coupled to the armature in a suitable way.
  • the at least one compression chamber can be formed by at least one bellows, which is positioned between the armature and a counterpart so that the back-and-forth linear motion of the armature produces a pumping action of the at least one bellows.
  • a compressor assembly of this kind can also be referred to as a bellows pump compressor.
  • the at least one bellows can be made of a material, which, after the deformation that occurs during the compression, quickly returns to its original shape so as to be available for the next compression procedure.
  • the coil, the armature, and the counterpart can be embodied in annular form and can be arranged coaxially to one another, preferably relative to the longitudinal axis of the wheel suspension. If only one bellows is provided, then it can be embodied in annular form and likewise arranged coaxially.
  • the compressor assembly can include several bellows that are arranged so that they are distributed in annular fashion between the armature and the counterpart. In this case, each bellows forms a separate compression chamber.
  • Figs, la, lb, and lc show a sectional view and associated detail views of a vehicle wheel that is mounted on a wheel hub with a ring piston compressor positioned on the inside of the hub;
  • Figs. 2a, 2b, and 2c show a perspective exploded view of a ring piston compressor positioned on the outside of a wheel hub as well as an associated sectional view and perspective detail view;
  • Fig. 3 shows a sectional view of a ring piston compressor with an alternative clutch device in comparison to Figs. 2a, 2b, and 2c;
  • Fig. 4 shows a sectional view of a ring piston compressor with a double-acting ring piston
  • Figs. 5a and 5b show a perspective exploded view and an assembled view of a bellows pump compressor.
  • Fig. la shows a sectional view of a vehicle wheel 10 whose rim 12 is mounted by means of a plurality of wheel lug bolts 14 to a wheel hub 16, which in turn is supported on a wheel suspension 20 in rotary fashion by means of one or more ball bearings 18.
  • the wheel suspension 20 shown here includes a wheel mount and defines an axial direction along a longitudinal axis 22.
  • a compressor assembly 24 is provided, which is suitable for supplying pressure fluid to a tire (not shown here) that is mounted on the rim 12.
  • Fig. lb is an enlarged detail view of the region of the wheel hub 16 showing the compressor assembly 24.
  • the compressor assembly 24 in the example shown is a ring piston compressor, whose ring cylinder 26 is embodied as an annular recess in the wheel hub 16 or more precisely, on inside of the wheel hub 16 oriented toward the vehicle.
  • the ring cylinder 26 thus constitutes an annular cavity in which a ring piston 28 is accommodated so that it can move in the axial direction of the longitudinal axis 22.
  • a compression chamber is formed between the ring cylinder 26 and the ring piston 28.
  • pressure fluid such as air can be pressurized in the compression chamber and subsequently supplied to the tire via a pressure fluid line (not shown here).
  • the ring cylinder 26 and the ring piston 28 are arranged coaxially to each other around the longitudinal axis 22 defined by the wheel suspension 20 in order to minimize compression procedure-induced imbalances in the vehicle wheel 10.
  • a transforming device which produces the linear motion of the ring piston 28 from a rotary motion of the annular piston 28 when the wheel hub 16 is rotating around the wheel suspension 20.
  • An enlarged depiction of the transforming device is shown in the detail view of Fig. lc. As the drawing shows, the
  • transforming device includes engaging elements 30 that are distributed in the circumference direction and can be held so that they are affixed to the wheel suspension; in the example shown, these elements are embodied as spherical and engage in a sinusoidal circumferential groove 32 provided in the outer circumference of the ring piston 28.
  • a sample sinusoidal curve of such a groove is shown in Fig. 2a and is labeled with the reference numeral 48 (the difference should be noted, however, that the sinusoidal circumferential groove 48 shown in Fig. 2a is situated in the inner circumference of the ring, not in its outer circumference).
  • the engaging elements 30 are connected to an annular hub-mounted clutch element 34, which is part of a clutch device.
  • the clutch device also includes an annular clutch element 36, which is affixed to the wheel suspension and to which electrical energy can be supplied in order to produce an electromagnetic force that pulls the hub-mounted clutch element 34 toward the clutch element 36 affixed to the wheel suspension in order to produce a non-positive connection between the two clutch elements 34 and 36.
  • the clutch element 34 that initially rotates along with the wheel hub 16 when the wheel hub 16 rotates around the wheel suspension 20 can be slowed and immobilized in order to hold the engaging elements 30 so that they are affixed to the wheel suspension. This is how the engagement of the engaging elements 30 takes place.
  • the compressor assembly 24 is positioned on the inside of the wheel hub 16 oriented toward the vehicle.
  • Such a placement is particularly suitable for passenger cars in which there is generally only a very limited amount of space in the vicinity of the wheel hub available for attaching additional components.
  • the compressor assembly can also be accommodated on the outside of the wheel hub 16.
  • Such a variant of a ring piston compressor is shown in Figs. 2a, 2b, and 2c.
  • Fig. 2a is a perspective exploded view of a ring piston compressor assembly 38 mounted on the outside of a wheel hub 16.
  • the wheel hub 16 is supported in rotary fashion on a wheel suspension 20, the wheel suspension 20 having an axle stub 40 that protrudes beyond the wheel hub 16 in the axial direction on the outside of the wheel hub 16.
  • the compressor assembly 38 shown here is embodied in the form of a separate subassembly, which can be mounted as such to the outside of the wheel hub 16.
  • the compressor assembly 38 includes a ring cylinder 42 for accommodating a ring piston 44.
  • a seal 46 can be provided at the end of the ring piston 44 oriented away from the wheel hub 16 in order to seal the ring piston 44 against the ring cylinder 42.
  • the ring piston 44 has a sinusoidal circumferential groove 48 in its inner circumference, which can be engaged by engaging elements 52 that are arranged distributed around the circumference of an engaging element support 50.
  • the compressor assembly 38 has a clutch element 56, which is affixed to the wheel suspension and can be connected to a disk-shaped axle stub cap 54, and a hub-mounted clutch element 58, which can be connected to the engaging element support 50.
  • the axle stub cap 54 can be connected to the axle stub 40.
  • An annular bellows 60 is also provided, which, when inflated, presses the two clutch elements 56 and 58 against each other in order to produce a non- positive connection between the two clutch elements 56 and 58.
  • the compressor assembly 38 has a hub connection ring 62, which is provided for connecting the above-mentioned hub-mounted components to the wheel hub 16. As shown in Fig. 2a, all of the above-mentioned components are arranged coaxially to one another around the longitudinal axis 22 of the wheel suspension 20.
  • Fig. 2a shows a sectional view of the ring piston compressor assembly 38 in the assembled state
  • Fig. 2c shows a corresponding perspective detail view.
  • the compressor assembly 38 is shown without the wheel hub 16 and wheel suspension 20 in both figures.
  • a feather key 63 is provided, which can be fitted into a corresponding recess in the axle stub 40 of the wheel suspension 20 in order to provide a rotation prevention means for the axle stub cap 54.
  • the clutch element 56 affixed to the wheel suspension is fastened to the radially outer end of the axle stub cap 54 and is thus held so that it is affixed to the wheel suspension.
  • the hub-mounted clutch element 58 is positioned on the axially opposite side from the clutch element 56 affixed to the wheel suspension and in the disengaged state, is spaced apart from the clutch element 56 affixed to the wheel suspension.
  • the hub-mounted clutch element 58 is in turn connected to the engaging element support 50 that has engaging elements 52 distributed around its circumference, which in this case are embodied in the form of radially protruding pins, for example.
  • the pins in the example shown are in sliding contact directly with the sinusoidal circumferential groove 48 of the ring piston 44.
  • the pins can also have bearing rings or ball bearings placed onto them, which roll when the pins move along the sinusoidal circumferential groove 48, thus reducing the friction forces that occur between the pins and the ring piston 44 in that instead of a sliding friction, a rolling friction now occurs.
  • the ring piston 44 and the ring cylinder 42 jointly define a compression chamber 64, with the annular seal 46 being mounted at the end of the ring piston 44 in order to seal it against the ring cylinder 42.
  • the annular bellows 60 - which is held by a clutch support 65 in the example in Figs. 2b and 2c - can be filled with pressure fluid in order to shift the bellows 60 into an inflated state.
  • the circumference of the annular bellows 60 increases so that the hub-mounted clutch element 58 is pressed against the clutch element 56 affixed to the wheel suspension and produces a non-positive connection between the two clutch elements 56 and 58.
  • the hub-mounted clutch element 58 that initially rotates with the wheel hub 16 when the wheel hub 16 rotates around the wheel suspension 20 can thus be slowed and brought to a standstill in order to hold the engaging elements 52, which are connected to the hub-mounted clutch element 58 by means of the engaging element support 50, so that they are affixed to the wheel suspension. This disengages the engaging elements 52.
  • a pressure fluid line 70 (see Fig. 2c) is provided by means of which the annular bellows 60 can be filled with pressure fluid from the tire of the vehicle wheel.
  • a valve 72 is provided, which is contacted by the pressure fluid from the tire and which opens when the tire pressure falls below a threshold value in order to fill the annular bellows 60 with the pressure fluid and shift it into the inflated state.
  • an electronic control unit (not show here) can be provided, which receives measurement data from a tire pressure sensor (integrated into the valve 72, for example) and which sends appropriate switching signals to the valve 72 in order to open it when the tire pressure falls below the threshold value.
  • the valve 72 can also be used to release pressure fluid from the annular bellows 60 in the inflated state when the engaging elements 52 are to be disengaged.
  • the compressor assembly 38 can include a generator device (not shown here) for producing electrical energy, which produces the electrical energy when the wheel hub 16 rotates around the wheel suspension 20.
  • the generator device can include a hub-mounted rotor and, cooperating with it, a stator affixed to the wheel suspension that can be
  • an energy storage device can be provided, which buffers electrical energy produced by the generator device in order to supply electrical energy to the above-mentioned consumer components independently of the rotation.
  • the ring piston 44 or the seal 46 are provided with pressure fluid inlets (not shown here), through which the pressure fluid can travel into the compression chamber 64 during an intake stroke of the ring piston 44.
  • the pressure fluid inlets can, for example, extend via openings 66 provided in the ring cylinder 42 and corresponding bores in the ring piston 44 and the annular seal 46 in order to then be fed into the compression chamber 64 via reed valves (not shown here) that are arranged distributed around the seal 46 in the circumference direction.
  • the reed valves permit pressure fluid to be allowed into the compression chamber 64 during an intake stroke of the ring piston 44 and close with a compression stroke of the ring piston 44 so that pressure fluid in the compression chamber 64 can be pressurized.
  • the ring cylinder 42 is provided with a pressure fluid outlet 68 (see Fig. 2c) through which the pressure fluid, which is pressurized in a compression stroke of the ring piston 44, can travel from the compression chamber 64 into a pressure fluid line (not shown here) leading to the tire.
  • the pressure fluid outlet 68 can be provided with a check valve that prevents pressurized pressure fluid from flowing out of the pressure fluid line and back into the compression chamber 64.
  • a transforming device with the sinusoidal circumferential groove 48 and the engaging elements 52 described above with reference to Figs. 2a, 2b, and 2b that are used to produce the linear motion of the ring piston 44
  • a transforming device could be used in which the end of the ring piston 44 oriented toward the wheel suspension 20 is itself embodied as sinusoidal.
  • Such a sinusoidal end surface can be produced, for example, by cutting the ring piston 44 along the sinusoidal circumferential groove 48 shown in Fig. 2a.
  • a counterpart which can be held so that it is affixed to the wheel suspension and has a likewise sinusoidally embodied end, can be used, which can be brought into a precisely fitting engagement with the sinusoidal end of the ring piston.
  • the sinusoidal ends slide against each other so that a back-and-forth linear motion of the ring piston in the axial direction is produced.
  • a suitable clutch device can be provided in order to engage and disengage the ring piston and the counterpart.
  • Fig. 3 also shows a sectional view of a ring piston compressor 38 with an alternative clutch device in comparison to the embodiment in Figs. 2a, 2b, and 2c.
  • the difference between the clutch device shown here and the one in Figs. 2a, 2b, and 2c lies particularly in the fact that when the wheel hub 16 rotates around the axis of the wheel suspension 20, the annular bellows 60 does not rotate and is instead always held by the axle stub cap 54 so that it is affixed to the wheel suspension.
  • the annular bellows 60 cooperates with the clutch element 56, which is affixed to the wheel suspension and is shown here by way of example as a multi-plate clutch element, in order, when the bellows is in the inflated state, to produce a non-positive connection between the clutch element 56 and the hub-mounted clutch element 58, which is in turn connected to engaging elements 52 for engaging in the sinusoidal circumferential groove 48 of the ring piston 44.
  • the pressure fluid line 70 for inflating the annular bellows 60 in this case extends at least partially through the axle stub cap 54.
  • Fig. 4 is a schematic sectional view of another variant of a ring piston compressor 38 with a double-acting ring piston.
  • the compressor does not have just one compression chamber 64, but instead has two compression chambers 64-1 and 64-2 in all, which are each formed between opposing piston sections 44-1 and 44-2, respectively, of the ring piston 44 and associated ring cylinders 42-1 and 42-2, respectively.
  • the stroke motions of the ring piston 44 in both movement directions can be used for corresponding compression procedures, thus making it possible to correspondingly increase the delivery volume of the compressor.
  • corresponding seals, pressure fluid inlets, and pressure fluid outlets must naturally be provided for each of the two compression chambers 64- 1 and 64-2.
  • Fig. 5a shows a perspective exploded view of another variant of a compressor assembly 76, which is embodied in the form of a bellows pump compressor.
  • a compressor assembly 76 which is embodied in the form of a bellows pump compressor.
  • the bellows pump compressor assembly 76 the electromagnetic force generated by supplying energy to an electromagnetic coil, which is affixed to the wheel suspension and acts on a hub-mounted armature, is used for drive purposes.
  • the bellows pump compressor assembly 76 includes an electromagnetic coil 78, which includes two approximately half-ring-shaped inner coil parts 80 and two approximately half-ring-shaped outer coil parts 82, which are arranged coaxially to one another around a longitudinal axis 84. Between the respective inner and outer coil parts 80 and 82, a radial space is provided in which an annular armature 86 fits in a movable fashion.
  • the magnetic field produced by the coil 78 can move the armature 86 back and forth in the axial direction.
  • the compression chambers of the compressor assembly 76 are composed of bellows 88, which are positioned between the armature 86 and a hub-mounted counterpart 90 so that the back- and-forth linear motion of the armature 86 exerts a compressing action on the bellows 88.
  • the bellows 88 can be provided with suitable pressure fluid inlets and outlets (not shown here), via which the pressure fluid, which has been taken in and pressurized, can be conveyed to the tire.
  • the pumping action can be carried out with a suitable frequency in order to supply a delivery volume that is sufficient to fill a tire.
  • the bellows 88 can be made of a material, which, after the deformation that occurs during the compression, quickly returns to its original shape so as to be ready for the next compression procedure.
  • the coil 78, the armature 86, and the counterpart 90 are arranged coaxially to one another with reference to the longitudinal axis 84.
  • the bellows 88 are correspondingly positioned so that they are distributed in the circumference direction between the armature 86 and the counterpart 90.
  • plate parts that cover the bellows 88 are mounted, between which the bellows 88 are squeezed during the compression procedure.
  • Fig. 5b shows the bellows pump compressor assembly 76 in the assembled state.
  • the compression procedure for supplying pressure fluid to a tire can take place not only during driving, but also when at rest.
  • the electrical energy that is required for supplying energy to the coil 78 can be provided by an energy source that is present in a vehicle, e.g. by the main battery of the vehicle.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Vehicle Body Suspensions (AREA)

Abstract

A compressor assembly (38) for supplying pressure fluid to a tire of a vehicle wheel that is mountable on a wheel hub, said wheel hub being supportable in rotary fashion on a wheel suspension that defines an axial direction. The compressor assembly (38) defines at least one compression chamber (64) and includes a drive that is equipped to produce a back-and- forth linear motion of a hub-mounted compressor component (44) in the axial direction through a cooperation between the hub-mounted compressor component (44) and a component (52) affixed to the wheel suspension, the linear motion of the compressor component (44) producing a change in the volume of the at least one compression chamber (64) and thus pressurizing pressure fluid that is to be conveyed into the tire.

Description

Compressor Assembly for Supplying a Pressure Fluid to a Tire
The present invention generally relates to the field of tire pressure regulation and in particular, to a compressor assembly for supplying pressure fluid to a tire of a vehicle wheel that can be mounted on a wheel hub.
In order to fill a vehicle tire with a pressure fluid such as compressed air, it is known to provide the vehicle wheel with a tire valve via which the pressure fluid can be introduced into the tire. In vehicles such as passenger cars, trucks, or commercial vehicles, tire valves are usually placed in the region of a rim on which the tire is mounted so that they are easily accessible from the outside. A pressure fluid source external to the vehicle can be connected to the tire valve, for example by means of a hose line, in order to manually check the tire pressure and correct it as needed.
Vehicle-mounted pressure fluid supply systems are also known, which make it possible to autonomously fill a vehicle tire with pressure fluid. For this purpose, from a central vehicle- mounted pressure fluid source such as a compressor or pressure reservoir, pressure fluid lines are routed to the wheels and are connected to the tire valves there. At the transition from the vehicle frame to the wheels, so-called rotary feedthroughs are provided, which make it possible to fill the tires with pressure fluid even while driving, i.e. when the wheels are turning. It is thus possible to adapt the tire pressure, for example to changing load conditions, road surfaces, and ambient temperatures.
One basic disadvantage of such systems, however, is that it is necessary to bridge across long distances of pressure fluid line, which generally results in high construction and maintenance costs. It is also difficult to achieve reliability and long-term functionality of the rotary
feedthroughs, which are subjected to constant stress by the turning of the wheels during driving.
The object of the invention, therefore, is to disclose a solution which can autonomously fill a vehicle wheel with pressure fluid during driving and can be implemented in a simple and reliable way in terms of its design. l According to the invention, this object is attained by means of a compressor assembly for supplying pressure fluid to a tire of a vehicle wheel that can be mounted on a wheel hub, said wheel hub being supportable in rotary fashion on a wheel suspension that defines an axial direction. The compressor assembly is distinguished by the fact that it defines at least one compression chamber and includes a drive that is equipped to produce a back-and-forth linear motion of a hub-mounted compressor component in the axial direction through a cooperation between the compressor component and a component affixed to the wheel suspension, the linear motion of the compressor component producing a change in the volume of the at least one compression chamber and thus pressurizing pressure fluid that is to be conveyed into the tire. In the broader sense, the invention can therefore relate to a system for supplying pressure fluid to a tire, comprising a vehicle wheel, a compressor assembly, and a wheel hub.
The at least one compression chamber of the compressor assembly is situated in the hub and - together with the wheel hub - is subjected to a rotary motion relative to the wheel suspension during driving. The actual compression procedure therefore takes place in the hub and, when a vehicle wheel is mounted on the wheel hub, makes it possible to independently supply pressure fluid for the tire directly in the vehicle wheel and thus even during driving. Hub-mounted components are understood to be those components that are directly or indirectly connected to the wheel hub so that when a rotary motion of the wheel hub occurs, they rotate along with the wheel hub relative to the wheel suspension. The wheel suspension is affixed to the vehicle and can, for example, include a wheel mount or an axle stub of a vehicle axle. The fact that the linear motion of the compressor component occurs in the axial direction of the wheel suspension minimizes imbalances in the vehicle wheel resulting from an operation of the compressor assembly that occurs during driving.
In multi-wheeled vehicles, the compressor assembly according to the invention can be used to implement a decentralized pressure fluid supply system in which each vehicle wheel has its own pressure fluid supply unit. It is thus possible to avoid the long distances of pressure fluid line that must be provided in the vehicle in the pressure fluid supply systems mentioned at the beginning. It is also possible to eliminate the rotary feedthroughs, whose reliability and long- term functionality are hard to achieve, at the transition from the vehicle chassis to the rotatable vehicle wheels. The compressor assembly according to the invention makes it possible to achieve a fundamental change in known pressure fluid supply systems, moving away from a centralized
1 architecture and toward a decentralized architecture, which is essentially based on the idea of carrying out the compression procedure directly in the wheel hub or vehicle wheel.
According to the invention, the compressor assembly drive that is required for the compression procedure is implemented through the cooperation of the hub-mounted compressor component with the component affixed to the wheel suspension. In a first variant of such a drive, it is possible to make use of the movement of the wheel hub relative to the wheel suspension. Since the compressor component is hub-mounted, it rotates around the wheel suspension with the wheel hub during driving. The drive can include a transforming device, which produces the linear motion of the compressor component from a rotary motion of the compressor component when the wheel hub rotates around the wheel suspension.
The compressor assembly can include a preferably annular cylinder and the compressor component is a preferably annular piston that is accommodated in the cylinder so that the compression chamber is formed between the cylinder and the piston. An annular cylinder can also be referred to as a ring cylinder and an annular piston can also be referred to as a ring piston. Such a compressor assembly can then also be referred to as a ring piston compressor. The ring cylinder and the ring piston can be embodied as rotationally symmetrical and can be arranged coaxially to each other around the longitudinal axis defined by the wheel suspension in order to minimize imbalances in the vehicle wheel caused by the compressor assembly during driving. Naturally, instead of an annular piston, the compressor assembly can, for example, also have a cylindrical piston, which is accommodated in a cylindrical chamber. Through the linear motion of the piston in the cylinder produced by means of the transforming device during driving, a pressure fluid such as compressed air can be pressurized in the compression chamber and subsequently supplied to the tire via a short pressure fluid line.
At the end of the piston, a seal can be provided, which seals the piston against the cylinder. The piston and/or the seal can also be provided with at least one pressure fluid inlet via which pressure fluid can travel into the compression chamber during an intake stroke of the piston.
For this purpose, a pressure fluid inlet can, for example, be provided with a reed valve, which allows the inlet of pressure fluid into the compression chamber during an intake stroke of the piston and closes during a compression stroke of the piston so that pressure fluid that is present in the compression chamber can be pressurized. If a ring piston is provided with a plurality of pressure fluid inlets, then these can be positioned so that they are distributed in the circumference direction around the ring piston or seal.
In addition, the cylinder can be provided with at least one pressure fluid outlet via which the pressure fluid that is pressurized during a compression stroke of the piston can be conveyed from the compression chamber into a pressure fluid line that leads to the tire. The pressure fluid outlet can be provided with a check valve, which prevents pressurized pressure fluid from flowing out of the pressure fluid line and back into the compression chamber. If a ring cylinder is provided with a plurality of pressure fluid outlets, then these can be positioned so that they are distributed in the circumference direction around the ring cylinder.
The compressor assembly can be provided as a separate subassembly, which is independent of the wheel hub. The cylinder can thus be embodied as a separates component, which, together with the other components of the compressor assembly, can be mounted as a subassembly to the wheel hub. According to another embodiment, the cylinder can be embodied as a preferably annular recess in the wheel hub, for example on an inside or outside of the wheel hub. In this case, the wheel hub is a part of the compressor assembly.
In order to produce the linear motion of the piston when the wheel hub rotates around the axis defined by the wheel suspension, the piston can have a sinusoidal circumferential groove extending around its circumference and the transforming device can have at least one engaging element, which can be affixed to the wheel suspension and engages in the sinusoidal circumferential groove in order, when the wheel hub rotates relative to the wheel suspension, to superimpose the linear motion of the piston on the rotary motion of the piston or - in other words - in order to impart the desired linear motion to the rotating piston. In this case, the above-mentioned cooperation of the hub-mounted compressor with the component affixed to the wheel suspension is implemented between the at least one engaging element and the piston. The at least one engaging element can be positioned in a preferably annular engaging element support, which in turn is positioned in a rotationally symmetrical around the longitudinal axis that is defined by the wheel suspension. In a ring piston, the sinusoidal circumferential groove can be positioned either on the outer circumference or the inner circumference.
In one embodiment, the transforming device can also include a plurality of engaging elements that can be affixed to the wheel suspension, which are distributed around the circumference of the engaging element support and which engage in the sinusoidal circumferential groove of the piston. For example, the engaging elements can be spaced apart from one another along the groove by a whole sinusoidal oscillation (or possibly a multiple thereof). It is thus possible to assure a stable and accurately fitting guidance of the piston in the cylinder and to prevent the piston from tilting relative to the longitudinal axis.
So that the compressor assembly is not driven continuously during driving, but only when a pressure regulation of the tire is actually desired, the transforming device can include a clutch device by means of which on the one hand, the at least one engaging element can be engaged in order to produce a connection affixing the at least one engaging element to the wheel suspension and by means of which on the other hand, the at least one engaging element can be disengaged in order to release the connection affixing the at least one engaging element to the wheel suspension. If the at least one engaging element is disengaged, then it is able to rotate together with the piston - or the entire wheel hub - around the wheel suspension so that the linear motion is not superimposed with the rotary motion of the piston and as a result, the compressor assembly is not driven.
In one embodiment, the clutch device can be electromagnetically actuated. In this case, the clutch device can include a preferably annular clutch element affixed to the wheel suspension and a hub-mounted, preferably annular clutch element that is connected to the at least one engaging element; through the supply of energy to the clutch element affixed to the wheel suspension, an electromagnetic force, which acts between the hub-mounted clutch element and the clutch element affixed to the wheel suspension and presses the two clutch elements against each other in order to produce a non-positive connection between the at least one engaging element and the clutch element affixed to the wheel suspension.
In another embodiment, the clutch device can be actuated in a pressure fluid-controlled way. In this case, the clutch device can include a preferably annular engaging element affixed to the wheel suspension, a hub-mounted, preferably annular clutch element that is connected to the at least one engaging element, and a preferably annular bellows that cooperates with the hub- mounted clutch element or with the clutch element affixed to the wheel suspension; when in the inflated state, this bellows presses the two clutch elements against each other in order to produce a non-positive connection between the at least one engaging element and the clutch element affixed to the wheel suspension and when in the non-inflated state, it cancels the non-positive connection between the hub-mounted clutch element and the clutch element affixed to the wheel suspension. In both embodiments of the clutch device, the hub-mounted clutch element can be connected to the at least one engaging element via the engaging element support. Like the engaging element support, both the hub-mounted clutch element and the clutch element affixed to the wheel suspension can be embodied as rotationally symmetrical and coaxial to each other relative to the longitudinal axis of the wheel suspension. It goes without saying that instead of an annular engaging element support, bellows, or coupling element that is hub-mounted or affixed to the wheel suspension, it is also possible to use a disk-shaped engaging element support, bellows, or coupling element that is hub-mounted or affixed to the wheel suspension. The clutch element affixed to the wheel suspension can, for example, be attached to the wheel suspension by means of a radially extending axle stub cap that is fastened to an axle stub of a vehicle axle.
With a pressure fluid-actuatable clutch device, the bellows can be filled with pressure fluid from the tire of the vehicle wheel via a pressure fluid line. In the pressure fluid line, a valve can be provided that is contacted by the pressure fluid from the tire, which fluid is at the tire pressure, and that, when the tire pressure falls below a threshold value, opens in order to fill the bellows with the pressure fluid and shift it into the inflated state. To control the valve, the compressor assembly can include an electronic control unit, which sends appropriate switching signals to the valve. The control unit can be connected to a tire pressure sensor for monitoring the tire pressure; then the tire pressure falls below the threshold value, the control unit emits a switching signal to open the valve. Both the valve and the tire pressure sensor can be positioned in a central region around the longitudinal axis of the wheel suspension in order to minimize any imbalances of the vehicle wheel during driving.
In order to generate the electrical energy that is required for the electronic control unit and the tire pressure sensor or the above-mentioned electromagnetically actuatable clutch device, the compressor assembly can have a generator device for generating electrical energy as the wheel hub rotates around the wheel suspension. The generator device can include a hub- mounted rotor and, cooperating with it, a stator that is affixed to the wheel suspension. An energy storage device can also be provided, which buffers electrical energy produced by the generator device in order to ensure a supply of electrical energy to the above-mentioned consumer components independently of the operation of the generator device.
In the above-described first drive variant of the compressor assembly, the movement of the wheel hub relative to the wheel suspension is made use of in order to implement the drive of the compressor assembly. Naturally in this case, the compression procedure for preparing pressure fluid for the tire can only take place during driving.
In a second variant of the drive of the compressor assembly, the cooperation of the hub- mounted compressor component with the component affixed to the wheel suspension can also be implemented in that the drive has an electromagnetic coil and the compressor component is an armature, which can be moved back and forth in the axial direction by an electromagnetic force generated by supplying energy to the coil. The electromagnetic coil can be affixed to the wheel suspension and the armature can be positioned in the hub.
Since it is not necessary for the wheel hub to move relative to the wheel suspension in this drive variant, the compression procedure for supplying pressure fluid to the tire can also take place when the vehicle is at rest. The electrical energy that is necessary in order to supply energy to the coil can, for example, be supplied by an energy source in the vehicle, for example the main battery of a vehicle. If the coil is affixed to the wheel suspension, then corresponding supply lines can easily be routed from the energy source to the coil.
In one embodiment of the second drive variant, the at least one compression chamber, as described above for the first drive variant, can be formed by a preferably annular piston accommodated in a preferably annular cylinder; in this case, the linear motion of the piston is produced by the armature that is driven by the coil. To this end, the piston can be coupled to the armature in a suitable way.
In another embodiment, the at least one compression chamber can be formed by at least one bellows, which is positioned between the armature and a counterpart so that the back-and-forth linear motion of the armature produces a pumping action of the at least one bellows. A compressor assembly of this kind can also be referred to as a bellows pump compressor. The at least one bellows can be made of a material, which, after the deformation that occurs during the compression, quickly returns to its original shape so as to be available for the next compression procedure.
The coil, the armature, and the counterpart can be embodied in annular form and can be arranged coaxially to one another, preferably relative to the longitudinal axis of the wheel suspension. If only one bellows is provided, then it can be embodied in annular form and likewise arranged coaxially. In another embodiment, the compressor assembly can include several bellows that are arranged so that they are distributed in annular fashion between the armature and the counterpart. In this case, each bellows forms a separate compression chamber.
Several exemplary embodiments of a compressor assembly according to the invention will be explained in greater detail below with reference to the accompanying schematic drawings. In the drawings:
Figs, la, lb, and lc show a sectional view and associated detail views of a vehicle wheel that is mounted on a wheel hub with a ring piston compressor positioned on the inside of the hub;
Figs. 2a, 2b, and 2c show a perspective exploded view of a ring piston compressor positioned on the outside of a wheel hub as well as an associated sectional view and perspective detail view;
Fig. 3 shows a sectional view of a ring piston compressor with an alternative clutch device in comparison to Figs. 2a, 2b, and 2c;
Fig. 4 shows a sectional view of a ring piston compressor with a double-acting ring piston; and
Figs. 5a and 5b show a perspective exploded view and an assembled view of a bellows pump compressor.
In the following description of exemplary embodiments, elements that are the same or that function in the same way have been provided with the same reference numerals.
Fig. la shows a sectional view of a vehicle wheel 10 whose rim 12 is mounted by means of a plurality of wheel lug bolts 14 to a wheel hub 16, which in turn is supported on a wheel suspension 20 in rotary fashion by means of one or more ball bearings 18. The wheel suspension 20 shown here includes a wheel mount and defines an axial direction along a longitudinal axis 22. On the inside of the wheel hub 16 oriented toward the vehicle, a compressor assembly 24 is provided, which is suitable for supplying pressure fluid to a tire (not shown here) that is mounted on the rim 12. Fig. lb is an enlarged detail view of the region of the wheel hub 16 showing the compressor assembly 24. The compressor assembly 24 in the example shown is a ring piston compressor, whose ring cylinder 26 is embodied as an annular recess in the wheel hub 16 or more precisely, on inside of the wheel hub 16 oriented toward the vehicle. The ring cylinder 26 thus constitutes an annular cavity in which a ring piston 28 is accommodated so that it can move in the axial direction of the longitudinal axis 22. A compression chamber is formed between the ring cylinder 26 and the ring piston 28. By means of a back-and-forth linear motion of the ring piston 28 in the ring cylinder 26, pressure fluid such as air can be pressurized in the compression chamber and subsequently supplied to the tire via a pressure fluid line (not shown here). The ring cylinder 26 and the ring piston 28 are arranged coaxially to each other around the longitudinal axis 22 defined by the wheel suspension 20 in order to minimize compression procedure-induced imbalances in the vehicle wheel 10.
In order to drive the compressor assembly 24, a transforming device is provided, which produces the linear motion of the ring piston 28 from a rotary motion of the annular piston 28 when the wheel hub 16 is rotating around the wheel suspension 20. An enlarged depiction of the transforming device is shown in the detail view of Fig. lc. As the drawing shows, the
transforming device includes engaging elements 30 that are distributed in the circumference direction and can be held so that they are affixed to the wheel suspension; in the example shown, these elements are embodied as spherical and engage in a sinusoidal circumferential groove 32 provided in the outer circumference of the ring piston 28. A sample sinusoidal curve of such a groove is shown in Fig. 2a and is labeled with the reference numeral 48 (the difference should be noted, however, that the sinusoidal circumferential groove 48 shown in Fig. 2a is situated in the inner circumference of the ring, not in its outer circumference).
The engaging elements 30 are connected to an annular hub-mounted clutch element 34, which is part of a clutch device. The clutch device also includes an annular clutch element 36, which is affixed to the wheel suspension and to which electrical energy can be supplied in order to produce an electromagnetic force that pulls the hub-mounted clutch element 34 toward the clutch element 36 affixed to the wheel suspension in order to produce a non-positive connection between the two clutch elements 34 and 36. In this way, the clutch element 34 that initially rotates along with the wheel hub 16 when the wheel hub 16 rotates around the wheel suspension 20 can be slowed and immobilized in order to hold the engaging elements 30 so that they are affixed to the wheel suspension. This is how the engagement of the engaging elements 30 takes place. Since the ring piston 28, when the engaging elements 30 are engaged, also continues to rotate together with the wheel hub 16, when the engaging elements 30, which are affixed to the wheel suspension, engage in the sinusoidal circumferential groove 32 of the ring piston 28, this causes a back-and-forth linear motion of the ring piston 28 to be superimposed on the rotary motion of the ring piston 28. In this way, pressure fluid in the compression chamber is pressurized and can be conveyed from the compression chamber to the tire. Once the supply of energy to the clutch element 36 affixed to the wheel suspension comes to an end and the electromagnetic force produced thereby disappears or falls off, the engaging elements 30 are disengaged again due to a cancelation of the non-positive connection between the two clutch elements 34 and 36, thus ending the compression procedure.
In the variant of a ring piston compressor shown in Figs, la, lb, and lc, the compressor assembly 24 is positioned on the inside of the wheel hub 16 oriented toward the vehicle. Such a placement is particularly suitable for passenger cars in which there is generally only a very limited amount of space in the vicinity of the wheel hub available for attaching additional components.
In other vehicle classes such as truck trailers, thanks to the more ample space conditions, the compressor assembly can also be accommodated on the outside of the wheel hub 16. Such a variant of a ring piston compressor is shown in Figs. 2a, 2b, and 2c.
Fig. 2a is a perspective exploded view of a ring piston compressor assembly 38 mounted on the outside of a wheel hub 16. Once again, the wheel hub 16 is supported in rotary fashion on a wheel suspension 20, the wheel suspension 20 having an axle stub 40 that protrudes beyond the wheel hub 16 in the axial direction on the outside of the wheel hub 16. The compressor assembly 38 shown here is embodied in the form of a separate subassembly, which can be mounted as such to the outside of the wheel hub 16.
The compressor assembly 38 includes a ring cylinder 42 for accommodating a ring piston 44. A seal 46 can be provided at the end of the ring piston 44 oriented away from the wheel hub 16 in order to seal the ring piston 44 against the ring cylinder 42. The ring piston 44 has a sinusoidal circumferential groove 48 in its inner circumference, which can be engaged by engaging elements 52 that are arranged distributed around the circumference of an engaging element support 50. In order to engage or disengage the engaging element support 50 and the engaging elements 52, the compressor assembly 38 has a clutch element 56, which is affixed to the wheel suspension and can be connected to a disk-shaped axle stub cap 54, and a hub-mounted clutch element 58, which can be connected to the engaging element support 50. The axle stub cap 54 can be connected to the axle stub 40. An annular bellows 60 is also provided, which, when inflated, presses the two clutch elements 56 and 58 against each other in order to produce a non- positive connection between the two clutch elements 56 and 58. Finally, the compressor assembly 38 has a hub connection ring 62, which is provided for connecting the above-mentioned hub-mounted components to the wheel hub 16. As shown in Fig. 2a, all of the above-mentioned components are arranged coaxially to one another around the longitudinal axis 22 of the wheel suspension 20.
The compressor assembly 38, which is only shown with a low level of detail in Fig. 2a, is shown in greater detail in the two subsequent Figs, 2b and 2c. Fig. 2b shows a sectional view of the ring piston compressor assembly 38 in the assembled state and Fig. 2c shows a corresponding perspective detail view. In the following, reference is made simultaneously to both Figs. 2b and 2c. For the sake of clarity, the compressor assembly 38 is shown without the wheel hub 16 and wheel suspension 20 in both figures.
As is apparent in Fig. 2b, on the inside of the axle stub cap 54, a feather key 63 is provided, which can be fitted into a corresponding recess in the axle stub 40 of the wheel suspension 20 in order to provide a rotation prevention means for the axle stub cap 54. The clutch element 56 affixed to the wheel suspension is fastened to the radially outer end of the axle stub cap 54 and is thus held so that it is affixed to the wheel suspension. The hub-mounted clutch element 58 is positioned on the axially opposite side from the clutch element 56 affixed to the wheel suspension and in the disengaged state, is spaced apart from the clutch element 56 affixed to the wheel suspension. The hub-mounted clutch element 58 is in turn connected to the engaging element support 50 that has engaging elements 52 distributed around its circumference, which in this case are embodied in the form of radially protruding pins, for example. The pins in the example shown are in sliding contact directly with the sinusoidal circumferential groove 48 of the ring piston 44. Naturally, however, the pins can also have bearing rings or ball bearings placed onto them, which roll when the pins move along the sinusoidal circumferential groove 48, thus reducing the friction forces that occur between the pins and the ring piston 44 in that instead of a sliding friction, a rolling friction now occurs. The ring piston 44 and the ring cylinder 42 jointly define a compression chamber 64, with the annular seal 46 being mounted at the end of the ring piston 44 in order to seal it against the ring cylinder 42.
When the engaging elements 52 are in the disengaged state and the wheel hub 16 rotates around the wheel suspension 20, all of the hub-mounted components of the compressor assembly 38 rotate along with the wheel hub 16, particularly also the hub-mounted clutch element 58 and, connected to the latter, the engaging element support 50 and its engaging elements 52. In this state, no relative movement between the engaging elements 52 and the ring piston 44 occurs and as a result, no linear motion is superimposed on the rotary motion of the annular piston 44.
In order to engage the engaging elements 52 and to produce the relative movement between the engaging elements 52 and the ring piston 44, which is necessary for the driving of the compressor assembly 38, the annular bellows 60 - which is held by a clutch support 65 in the example in Figs. 2b and 2c - can be filled with pressure fluid in order to shift the bellows 60 into an inflated state. During the inflating process, the circumference of the annular bellows 60 increases so that the hub-mounted clutch element 58 is pressed against the clutch element 56 affixed to the wheel suspension and produces a non-positive connection between the two clutch elements 56 and 58. The hub-mounted clutch element 58 that initially rotates with the wheel hub 16 when the wheel hub 16 rotates around the wheel suspension 20 can thus be slowed and brought to a standstill in order to hold the engaging elements 52, which are connected to the hub-mounted clutch element 58 by means of the engaging element support 50, so that they are affixed to the wheel suspension. This disengages the engaging elements 52.
Since the engagement - with the slowing and wheel suspension-affixed holding that it produces - is supposed to affect only the combination of the hub-mounted clutch element 58 and the engaging element support 50, but not the rest of the hub-mounted components such as the ring cylinder 42 or the annular bellows 60, corresponding bearings or clearances are provided, which permit the rest of the hub-mounted components to continue to rotate with the wheel hub 16 relative to the above-mentioned combination that is being held so that it is affixed to the wheel suspension. Corresponding bearings are only indicated in Figs. 2b and 2c.
Since the ring piston 44 continues to rotate with the wheel hub 16 when the engaging elements 52 are engaged, the wheel suspension-affixed holding of the engaging elements 52 in the sinusoidal circumferential groove 48 of the ring piston 44 results in the fact that a back-and-forth linear motion (indicated in Figs. 2b and 2c by double arrows in the compression chamber 64) is superimposed on the rotary motion of the annular piston 44. Pressure fluid in the compression chamber 64 is thus pressurized and can subsequently be supplied to the tire via a pressure fluid line (not shown here). Once pressure has been released from the annular bellows 60 again, its circumference decreases so that due to the cancelation of the non-positive connection between the two clutch elements 56 and 58, the engaging elements 52 are disengaged again and rotate with the ring piston 44 so that the compression procedure ends.
For the inflation of the annular bellows 60, a pressure fluid line 70 (see Fig. 2c) is provided by means of which the annular bellows 60 can be filled with pressure fluid from the tire of the vehicle wheel. In the course of the pressure fluid line 70, a valve 72 is provided, which is contacted by the pressure fluid from the tire and which opens when the tire pressure falls below a threshold value in order to fill the annular bellows 60 with the pressure fluid and shift it into the inflated state. To control the valve 72, an electronic control unit (not show here) can be provided, which receives measurement data from a tire pressure sensor (integrated into the valve 72, for example) and which sends appropriate switching signals to the valve 72 in order to open it when the tire pressure falls below the threshold value. The valve 72 can also be used to release pressure fluid from the annular bellows 60 in the inflated state when the engaging elements 52 are to be disengaged.
In order to supply the electrical energy that is needed for the electronic control unit and for the tire pressure sensor, the compressor assembly 38 can include a generator device (not shown here) for producing electrical energy, which produces the electrical energy when the wheel hub 16 rotates around the wheel suspension 20. The generator device can include a hub-mounted rotor and, cooperating with it, a stator affixed to the wheel suspension that can be
accommodated, for example, in the space identified with the reference numeral 74 (see Fig. 2b). In addition, an energy storage device can be provided, which buffers electrical energy produced by the generator device in order to supply electrical energy to the above-mentioned consumer components independently of the rotation.
So that the pressure fluid that is required for the compression procedure can travel into the compression chamber, the ring piston 44 or the seal 46 are provided with pressure fluid inlets (not shown here), through which the pressure fluid can travel into the compression chamber 64 during an intake stroke of the ring piston 44. The pressure fluid inlets can, for example, extend via openings 66 provided in the ring cylinder 42 and corresponding bores in the ring piston 44 and the annular seal 46 in order to then be fed into the compression chamber 64 via reed valves (not shown here) that are arranged distributed around the seal 46 in the circumference direction. The reed valves permit pressure fluid to be allowed into the compression chamber 64 during an intake stroke of the ring piston 44 and close with a compression stroke of the ring piston 44 so that pressure fluid in the compression chamber 64 can be pressurized. To permit the pressurized pressure fluid to be conveyed out of the compression chamber 64, the ring cylinder 42 is provided with a pressure fluid outlet 68 (see Fig. 2c) through which the pressure fluid, which is pressurized in a compression stroke of the ring piston 44, can travel from the compression chamber 64 into a pressure fluid line (not shown here) leading to the tire. The pressure fluid outlet 68 can be provided with a check valve that prevents pressurized pressure fluid from flowing out of the pressure fluid line and back into the compression chamber 64.
Naturally, instead of the transforming device with the sinusoidal circumferential groove 48 and the engaging elements 52 described above with reference to Figs. 2a, 2b, and 2b that are used to produce the linear motion of the ring piston 44, it is basically also conceivable to use other transforming devices. For example, a transforming device could be used in which the end of the ring piston 44 oriented toward the wheel suspension 20 is itself embodied as sinusoidal. Such a sinusoidal end surface can be produced, for example, by cutting the ring piston 44 along the sinusoidal circumferential groove 48 shown in Fig. 2a. Instead of the engaging element support 50, then a counterpart, which can be held so that it is affixed to the wheel suspension and has a likewise sinusoidally embodied end, can be used, which can be brought into a precisely fitting engagement with the sinusoidal end of the ring piston. When the ring piston is rotated relative to the counterpart that is held so that it is affixed to the wheel suspension, the sinusoidal ends then slide against each other so that a back-and-forth linear motion of the ring piston in the axial direction is produced. In this case as well, a suitable clutch device can be provided in order to engage and disengage the ring piston and the counterpart.
Fig. 3 also shows a sectional view of a ring piston compressor 38 with an alternative clutch device in comparison to the embodiment in Figs. 2a, 2b, and 2c. The difference between the clutch device shown here and the one in Figs. 2a, 2b, and 2c lies particularly in the fact that when the wheel hub 16 rotates around the axis of the wheel suspension 20, the annular bellows 60 does not rotate and is instead always held by the axle stub cap 54 so that it is affixed to the wheel suspension. In this case, the annular bellows 60 cooperates with the clutch element 56, which is affixed to the wheel suspension and is shown here by way of example as a multi-plate clutch element, in order, when the bellows is in the inflated state, to produce a non-positive connection between the clutch element 56 and the hub-mounted clutch element 58, which is in turn connected to engaging elements 52 for engaging in the sinusoidal circumferential groove 48 of the ring piston 44. As shown in Fig. 3, the pressure fluid line 70 for inflating the annular bellows 60 in this case extends at least partially through the axle stub cap 54.
Fig. 4 is a schematic sectional view of another variant of a ring piston compressor 38 with a double-acting ring piston. In this variant, unlike the embodiments in Figs. 2a to 2c and 3, the compressor does not have just one compression chamber 64, but instead has two compression chambers 64-1 and 64-2 in all, which are each formed between opposing piston sections 44-1 and 44-2, respectively, of the ring piston 44 and associated ring cylinders 42-1 and 42-2, respectively. When a relative movement between the engaging elements 52 and the ring piston 44 occurs, the stroke motions of the ring piston 44 in both movement directions can be used for corresponding compression procedures, thus making it possible to correspondingly increase the delivery volume of the compressor. In this case, corresponding seals, pressure fluid inlets, and pressure fluid outlets must naturally be provided for each of the two compression chambers 64- 1 and 64-2.
Fig. 5a shows a perspective exploded view of another variant of a compressor assembly 76, which is embodied in the form of a bellows pump compressor. By contrast with the ring piston compressors according to Figs. 1 and 2, in which the movement of the wheel hub 16 relative to the wheel suspension 20 that takes place during driving is used to implement the drive of the compressor, in the bellows pump compressor assembly 76, the electromagnetic force generated by supplying energy to an electromagnetic coil, which is affixed to the wheel suspension and acts on a hub-mounted armature, is used for drive purposes.
In the example shown in Fig. 5a, the bellows pump compressor assembly 76 includes an electromagnetic coil 78, which includes two approximately half-ring-shaped inner coil parts 80 and two approximately half-ring-shaped outer coil parts 82, which are arranged coaxially to one another around a longitudinal axis 84. Between the respective inner and outer coil parts 80 and 82, a radial space is provided in which an annular armature 86 fits in a movable fashion.
Through a suitable supply of energy to the coil 78, the magnetic field produced by the coil 78 can move the armature 86 back and forth in the axial direction.
The compression chambers of the compressor assembly 76 are composed of bellows 88, which are positioned between the armature 86 and a hub-mounted counterpart 90 so that the back- and-forth linear motion of the armature 86 exerts a compressing action on the bellows 88. The bellows 88 can be provided with suitable pressure fluid inlets and outlets (not shown here), via which the pressure fluid, which has been taken in and pressurized, can be conveyed to the tire. Depending on the material selection for the bellows 88 and their volume, the pumping action can be carried out with a suitable frequency in order to supply a delivery volume that is sufficient to fill a tire. To this end, the bellows 88 can be made of a material, which, after the deformation that occurs during the compression, quickly returns to its original shape so as to be ready for the next compression procedure.
As shown in Fig. 5a, the coil 78, the armature 86, and the counterpart 90 are arranged coaxially to one another with reference to the longitudinal axis 84. The bellows 88 are correspondingly positioned so that they are distributed in the circumference direction between the armature 86 and the counterpart 90. On both the armature 86 and the counterpart 90, plate parts that cover the bellows 88 are mounted, between which the bellows 88 are squeezed during the compression procedure. Fig. 5b shows the bellows pump compressor assembly 76 in the assembled state.
Since, by contrast with the ring piston compressors according to Figs. 1 and 2, a movement of the wheel hub 16 relative to the wheel suspension 20 is not required for the drive of the compressor assembly 76, in the compressor assembly 76, the compression procedure for supplying pressure fluid to a tire can take place not only during driving, but also when at rest. The electrical energy that is required for supplying energy to the coil 78 can be provided by an energy source that is present in a vehicle, e.g. by the main battery of the vehicle.

Claims

Patent Claims
1. A compressor assembly (24; 38; 76) for supplying pressure fluid to a tire of a vehicle wheel (10) that is mountable on a wheel hub (16), said wheel hub (16) being supportable in rotary fashion on a wheel suspension (20) that defines an axial direction, characterized in that the compressor assembly (24; 38; 76) defines at least one compression chamber (64) and includes a drive that is equipped to produce a back-and-forth linear motion of a hub- mounted compressor component (28; 44; 86) in the axial direction through a cooperation between the compressor component (28; 44; 86) and a component (30; 52; 78) affixed to the wheel suspension, the linear motion of the compressor component (28; 44; 86) producing a change in the volume of the at least one compression chamber (64) and thus pressurizing pressure fluid that is to be conveyed into the tire.
2. The compressor assembly (24; 38) according to claim 1,
characterized in that the drive includes a transforming device, which, as the wheel hub (16) rotates around the wheel suspension (20), produces the linear motion of the compressor component (28; 44) from a rotary motion of the compressor component (28; 44).
3. The compressor assembly (24; 38) according to claim 2,
characterized in that the compressor assembly (24; 38) includes a preferably annular cylinder (26; 42) and the compressor component is a preferably annular piston (28; 44) that is accommodated in the cylinder (26; 42), the at least one compression chamber (64) being formed between the cylinder (26; 42) and the piston (28; 44).
4. The compressor assembly (24) according to claim 3,
characterized in that the cylinder (26) is embodied as a preferably annular recess in the wheel hub (16).
5. The compressor assembly (24; 38) according to claim 3 or 4,
characterized in that the piston (28; 44) has a sinusoidal groove (32; 48) extending around its circumference, the transforming device having at least one engaging element (30; 52), which can be affixed to the wheel suspension and engages in the sinusoidal circumferential groove (32; 48) in order, when the wheel hub (16) rotates around the wheel suspension (20), to superimpose the linear motion of the piston (28; 44) on the rotary motion of the piston (28; 44).
6. The compressor assembly (38) according to claim 5,
characterized in that the at least one engaging element (52) is positioned on a preferably annular engaging element support (50).
7. The compressor assembly (38) according to claim 6,
characterized in that the transforming device includes a plurality of engaging elements (52) that can be affixed to the wheel suspension, that are positioned so that they are distributed around the circumference of the engaging element support (50), and that engage in the sinusoidal circumferential groove (48) of the piston (44).
8. The compressor assembly (24; 38) according to one of claims 5 to 7,
characterized in that the transforming device includes a clutch device by means of which the at least one engaging element (30; 52) can be engaged in order to produce a connection affixing the at least one engaging element (30; 52) to the wheel suspension and by means of which the at least one engaging element (30; 52) can be disengaged in order to release the connection affixing the at least one engaging element (30; 52) to the wheel suspension.
9. The compressor assembly (24) according to claim 8,
characterized in that the clutch device includes:
- a preferably annular clutch element (36) affixed to the wheel suspension; and
- a hub-mounted, preferably annular clutch element (34) connected to the at least one engaging element (30),
it being possible, by supplying energy to the clutch element (36) affixed to the wheel suspension, to generate an electromagnetic force that acts between the hub-mounted clutch element (34) and the clutch element (36) affixed to the wheel suspension and presses the two clutch elements (36, 34) against each other in order to produce a non-positive connection between the at least one engaging element (30) and the clutch element (36) affixed to the wheel suspension.
10. The compressor assembly (38) according to claim 8,
characterized in that the clutch device includes:
- a preferably annular clutch element (56) affixed to the wheel suspension;
- a hub-mounted, preferably annular clutch element (58) connected to the at least one engaging element; and - a preferably annular bellows (60) that cooperates with the hub-mounted clutch element (58) or with the clutch element (56) affixed to the wheel suspension; when in the inflated state, this bellows (60) presses the two clutch elements (56, 58) against each other in order to produce a non-positive connection between the at least one engaging element (52) and the clutch element (56) affixed to the wheel suspension and when in the non-inflated state, it cancels the non-positive connection between the hub-mounted clutch element (58) and the clutch element (56) affixed to the wheel suspension.
11. The compressor assembly (38) according to claim 10,
characterized in that the bellows (60) can be filled with pressure fluid from the tire of the vehicle wheel via a pressure fluid line (70).
12. The compressor assembly (38) according to claim 11,
characterized in that in the pressure fluid line (70), a valve (72) is provided, which is contacted by the pressure fluid from the tire and which, when the tire pressure falls below a threshold value, opens in order to fill the bellows (60) with the pressure fluid and shift it into the inflated state.
13. The compressor assembly (24; 38) according to one of claims 1 to 12,
characterized in that the compressor assembly (24; 38) includes a generator device for generating electrical energy as the wheel hub rotates around the wheel suspension, the generator device including a hub-mounted rotor and, cooperating with it, a stator that is affixed to the wheel suspension.
14. The compressor assembly (76) according to claim 1,
characterized in that the drive includes an electromagnetic coil (78) and the compressor component is an armature (86) that can be moved back and forth in the axial direction by means of an electromagnetic force that is generated by energy being supplied to the coil (78).
15. The compressor assembly (76) according to claim 14,
characterized in that the electromagnetic coil (78) is affixed to the wheel suspension and the armature (86) is positioned in the hub.
16. The compressor assembly (76) according to claim 14 or 15,
characterized in that the at least one compression chamber is composed of at least one bellows (88), which is positioned between the armature (86) and a counterpart (90) in such a way that the back-and-forth linear motion of the armature (86) brings about a pumping action of the at least one bellows (88).
17. The compressor assembly (76) according to claim 16,
characterized in that the coil (78), the armature (86), and the counterpart (90) are embodied in annular form and are arranged coaxially to one another.
18. The compressor assembly (76) according to claim 17,
characterized in that the compressor assembly (76) includes several bellows (88), which are arranged so that they are distributed in annular fashion between the armature (86) and the counterpart (90).
PCT/US2017/047772 2016-08-19 2017-08-21 Compressor assembly for supplying a pressure fluid to a tire Ceased WO2018035518A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE102016010055.9A DE102016010055B3 (en) 2016-08-19 2016-08-19 Compressor arrangement for pressure medium supply of a tire
DE102016010055.9 2016-08-19
DE102016010054.0A DE102016010054B4 (en) 2016-08-19 2016-08-19 Compressor arrangement for supplying a tire with pressure medium
DE102016010054.0 2016-08-19

Publications (1)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020201512A1 (en) * 2019-04-05 2020-10-08 Hubtech Holding B.V. System for inflating a tire of a wheel, configured to be build inside or onto a hub of a vehicle

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR895854A (en) * 1942-02-28 1945-02-06 Device for automatically inflating a tire by taking advantage of the movement of the corresponding wheel
JP2007039013A (en) * 2005-06-27 2007-02-15 Toyota Motor Corp Pressure generator
WO2015063679A1 (en) * 2013-10-28 2015-05-07 NDLOVU, Raymond Device for controlling the pressure in a vehicle tyre
WO2015075661A1 (en) * 2013-11-22 2015-05-28 NDLOVU, Raymond Device for controlling the pressure in a vehicle tyre

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR895854A (en) * 1942-02-28 1945-02-06 Device for automatically inflating a tire by taking advantage of the movement of the corresponding wheel
JP2007039013A (en) * 2005-06-27 2007-02-15 Toyota Motor Corp Pressure generator
WO2015063679A1 (en) * 2013-10-28 2015-05-07 NDLOVU, Raymond Device for controlling the pressure in a vehicle tyre
WO2015075661A1 (en) * 2013-11-22 2015-05-28 NDLOVU, Raymond Device for controlling the pressure in a vehicle tyre

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020201512A1 (en) * 2019-04-05 2020-10-08 Hubtech Holding B.V. System for inflating a tire of a wheel, configured to be build inside or onto a hub of a vehicle
NL2022873B1 (en) * 2019-04-05 2020-10-08 Hubtech Holding B V System for inflating a tire of a wheel, configured to be build inside or onto a hub of a vehicle.

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