WO2009092395A1 - Système de vérin pneumatique et sa méthode de commande - Google Patents

Système de vérin pneumatique et sa méthode de commande Download PDF

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Publication number
WO2009092395A1
WO2009092395A1 PCT/EP2008/000540 EP2008000540W WO2009092395A1 WO 2009092395 A1 WO2009092395 A1 WO 2009092395A1 EP 2008000540 W EP2008000540 W EP 2008000540W WO 2009092395 A1 WO2009092395 A1 WO 2009092395A1
Authority
WO
WIPO (PCT)
Prior art keywords
pilot
piston
valve
valve member
pilot piston
Prior art date
Application number
PCT/EP2008/000540
Other languages
English (en)
Inventor
Audun Bruer
Christian Bratli
Original Assignee
Kongsberg Automotive As
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
Application filed by Kongsberg Automotive As filed Critical Kongsberg Automotive As
Priority to PCT/EP2008/000540 priority Critical patent/WO2009092395A1/fr
Publication of WO2009092395A1 publication Critical patent/WO2009092395A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D48/00—External control of clutches
    • F16D48/02—Control by fluid pressure
    • F16D48/04—Control by fluid pressure providing power assistance
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D48/00—External control of clutches
    • F16D48/02—Control by fluid pressure
    • F16D2048/0209—Control by fluid pressure characterised by fluid valves having control pistons, e.g. spools
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D48/00—External control of clutches
    • F16D48/02—Control by fluid pressure
    • F16D2048/0212—Details of pistons for master or slave cylinders especially adapted for fluid control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D48/00—External control of clutches
    • F16D48/02—Control by fluid pressure
    • F16D2048/0221—Valves for clutch control systems; Details thereof

Definitions

  • the present invention relates to a pneumatic actuator system for usage in a clutch system of a vehicle and a method for actuating such a system.
  • the system comprises an actuator piston which is arranged to be actuated by pressure in a working chamber, a pilot valve for controlling the pressure in the working chamber and a control unit for controlling a control force, wherein the pilot valve comprises a pilot piston, a first valve member, and a pilot piston spring between the pilot piston and the first valve member for biasing the pilot piston against the control force, and wherein the pilot valve has a first operating state, a second operating state and a closed state, wherein the state of the pilot valve depends on the control force.
  • Pneumatic actuator systems are often used for controlling the fluid flowing in and out of a clutch actuator, especially where the working medium is pressurised air.
  • Pneumatic clutch actuators are most commonly used for actuation of normally engaged clutches, also referred to as normally closed clutches.
  • Such clutches are disengaged, or opened, by a working chamber of the clutch actuator when it is pressurised to overcome the force from an actuator spring, i.e. a clutch spring, and to move the actuator piston to disengage the clutch via a clutch release bearing.
  • an actuator spring i.e. a clutch spring
  • the clutch spring will urge the actuator piston to a retracted position, engaging the clutch.
  • the invention will however be applicable on normally disengaged, or normally open, clutches as well.
  • Pneumatic clutch actuators are primarily used in systems with automatic clutch actuation where exact positioning of the clutch plates, and hence the clutch actuator piston, is cru- cial for ensuring proper force transmission from the engine to the gearbox and maximising driving comfort.
  • valve package is provided to let air in and out of the working chamber of a clutch actuator.
  • the valve package includes two supply valves arranged for letting air into the chamber and two exhaust valves arranged to letting air out of the chamber.
  • Each of the pair of valves includes one valve with high flow capacity and one valve with small flow capacity. These are used for fast and fine control, respectively, of the pressure in the working chamber. This is necessary to achieve accurate positioning of the actuator piston which is crucial in a clutch application combined with potential for fast operation.
  • the valves are typically electronic solenoid valves.
  • valve package presents a substantial part, in most cases even the majority of the total cost for the system.
  • the valve package also occupies a substantial space. Since air is compressible the volume of the chamber to be controlled is critical. The larger the volume is the more complex the control of the position of the actuator piston becomes. In the prior art the valve package is arranged to control the volume in the working chamber of the clutch actuator.
  • a pneumatic actuator system according to the preamble of claim 1 for usage in a clutch system of a vehicle is provided, wherein the inventive pneumatic actuator system is characterised in that the pilot valve is arranged in mechanical or pneumatic communication with the actuator piston such that any movement of the actuator piston biases the pilot valve to its closed operating state.
  • any movement of the actuator piston regulates itself in such a way that the movement itself directly causes the pilot valve to close and therefore to stop the movement.
  • the fact that any actuator piston movement biases the pilot valve to its closed state makes control of the pilot valve less complex as the closing of the pilot valve is a consequence of the actuator piston movement itself. So there is no need for the control unit to close the pilot valve, i.e. the control unit does not need to compensate the control force.
  • a method for actuating an actuator system wherein the actuator piston is arranged to be actuated by a working chamber and an actuator spring in the one and the other direction, respectively, and the pilot valve further comprises a second valve member, and a valve spring biasing the second valve member towards the first valve member,
  • control unit controlling the control unit to apply a control force large enough to push the pilot piston to compress the pilot piston spring and to push the pilot piston against the second valve member to compress the valve spring and lifting from an air tight sealing contact with the first valve member
  • controlling the control unit to reduce the control force below the spring force of the pilot piston spring such that the pilot piston spring pushes the pilot piston to lift from an air tight sealing contact with the second valve member
  • either the first valve member or the pilot piston of the pilot valve is arranged in mechanical or pneumatic communication with the actuator piston such that it moves coinci- dently with the actuator piston.
  • This mechanical or pneumatic communication is a very simple and cost-effective way to achieve a self-regulating actuator piston which does not require a complicated and expensive control valve system.
  • One way to provide such a mechanical communication is simply to fix the first valve member of the pilot valve to the actuator piston such that it moves with it.
  • the pilot valve preferably operates in an axis of movement that corresponds to the axis of movement of the actuator piston.
  • Another way could be to keep the first valve member at a fixed location and provide a pneumatic communication between the actuator piston and the pilot piston such that it moves with it.
  • a pneumatic communication between the pilot valve and the actuator piston can be advantageous, if there are reasons for operating the pilot valve in an axis of movement different from the actuator piston.
  • Preferred embodiments of the pilot valve are designed such that the first operating state, the second operating state and the closed operating state of the pilot valve correspond to a first position, a second position and a closed position of the pilot piston, respectively, wherein the closed position is between the first and the second position. This means that the pilot valve must pass the closed operating state on its way from the first to the second operating state or vice versa.
  • the first position of the pilot piston corresponds to a position in which the pilot piston is farthest away from the first valve member due to the pilot piston spring biasing the pilot piston away from the first valve member.
  • This can be the initial operating state in which the pilot valve has an open outflow channel allowing an outflow of air out of the working chamber to an exhaust opening.
  • the working chamber is in a depressurised state such that no force is applied to a clutch rod that is connected to a clutch re- lease bearing.
  • the clutch can be in an engaged state in which the force of the engine is transmitted to the gearbox via the friction between the engaged clutch plates.
  • the second position of the pilot piston preferably corresponds to a position in which the pilot piston is closest to the first valve member due to the control force biasing the pilot piston to compress the pilot piston spring.
  • the first step of the inventive actuating method may be applied to switch the operating state of the pilot valve from the first to the second operating state.
  • the control unit may be activated to apply a control force large enough to push the pilot piston compressing the pilot piston spring.
  • the pilot piston then moves towards the first valve member until it reaches a closed position corresponding to a closed operating state in which the outflow channel to an exhaust opening is closed preventing an outflow of air out of the working chamber to an exhaust opening.
  • the closed position of the pilot piston preferably corresponds to an intermediate position in which the pilot piston is between the first and the second position due to an excess of the control force above the spring force of the pilot piston spring such that the pilot piston spring is compressed and the pilot valve is closed.
  • the pilot valve comprises a second valve member that is biased by a valve spring towards the first valve member, wherein an air tight sealing contact is provided between the first valve member and the second valve member when the pilot valve is in the closed or first position in order to prevent an inflow of air from an air pressure supply into the working chamber.
  • the first valve member, the second valve member and the pilot piston are preferably arranged coaxially such that the first valve member is arranged between the second valve member and the pilot piston when the pilot valve is in a first operating state.
  • the first step of the inventive actuating method for causing the pilot valve to switch from the first operating state to the second operating state therefore also implies to activate the control unit to apply a control force large enough to push the pilot piston against the second valve member compressing the valve spring and lifting from an air tight sealing contact with the first valve member. Otherwise, the pilot valve would remain in the closed operating state.
  • This configuration of an advantageous embodiment of the inventive system may be implemented by the first valve member having an inner annular opening with a diameter that is less than the diameter of the head of the second valve member.
  • the diameter of the head of the pilot piston may be less than the inner diameter of the first valve member, such that the front face of the pilot piston is able to be biased through the annular opening of the first valve member against the second valve member by the control force.
  • an air tight sealing contact is provided between the pilot piston and the second valve member when the pilot valve is in the closed or second position in order to prevent an outflow of air out of the working chamber to an exhaust opening.
  • the pilot piston comprises an inner air channel extending from the front face of the pilot piston to an outflow channel connected with the exhaust opening.
  • the opening of the inner air channel at the front face of the pilot piston is surrounded by an annular sealing surface that is biased against the head of the second valve member when the pilot valve is in the closed or second operating state.
  • the control force must be large enough to compress both the pilot piston spring and the valve spring, wherein the pilot piston is pushed against the second valve member such that the second valve member is urged away from the first valve member. Thereby, an inflow of air from an air pressure supply into the working chamber is allowed in the second operating state of the pilot valve .
  • the pilot valve of such an advantageous embodiment is biased to the closed operating state by the movement of the first valve member influencing the control force such that the pilot piston is pushed into air tight sealing contact with the second valve member and the second valve member is pushed into air tight sealing contact with the first valve member by the valve spring.
  • control unit For the pilot valve of such an advantageous embodiment to be actuated into the first operating state the control unit must be activated to apply a control force that is below the spring force of the pilot piston spring such that the pilot piston spring can push the pilot piston away from the second valve member, wherein the pilot piston lifts from the air tight sealing contact with the second valve member in order to allow an outflow of air out of the working chamber to an exhaust opening when the pilot valve is in a first operating state.
  • control unit comprises an inlet control valve for pressurising a control chamber and an outlet control valve for depressuris- ing the control chamber, wherein the control chamber is arranged to actuate the pilot piston by a pneumatic control force.
  • the control valves may be very simple, inexpensive electric valves with a small flow capacity for controlling the relatively small control chamber.
  • a position sensor may be provided for sensing the actual position of the actuator piston and/or the pilot piston in order to provide a feedback to the control unit. The position sensor in this case must be arranged in communication with the control unit in order to give the control unit information about the position of the actuator piston and/or the pilot piston.
  • control unit comprises an electric motor, wherein the control force of the electric motor is mechanically transferred to the pilot piston. It is further preferred that the electric motor is a step motor. In such a configuration a position sensor may not be necessary and the information about the position of the pilot piston and the actuator piston may be directly fed back to the control unit .
  • the pilot valve is arranged in pneumatic communication with the actuator piston such that any movement of the actuator piston affects the pressure in the control chamber.
  • the first valve member is kept fixed in this embodiment whereas the pilot piston is arranged in pneumatic communication with the actuator piston such that it moves co- incidently with it.
  • This configuration has the advantage that there is no mechanical contact needed between the actuator piston and the pilot valve. This can especially be advantageous if outer restrictions to the space occupied by the system require that the axis of movement of the pilot valve does not correspond to the axis of movement of the actuator piston.
  • Figs. 1 to 7 The first embodiment is shown in Figs, la-d to 3a, b, Figs. 4a-c to 6 refer to the sec- ond embodiment and the third embodiment is depicted in Figs. Ia and 7b.
  • Fig. Ia is a longitudinal cut through the yz-plane of the first embodiment of the inventive system with a pilot valve in an initial first operating state.
  • Fig. Ib is a detail view of the longitudinal cut through the yz-plane of the first embodiment of the inventive system with a pilot valve in an initial first operating state.
  • Fig. Ic is a detail view of the longitudinal cut through the xz-plane of the first embodiment of the inventive system with a pilot valve in an initial first operating state.
  • Fig. Id is top view on the first embodiment of the inventive system.
  • Fig. 2a is a longitudinal cut through the yz-plane of the first embodiment of the inventive system with a pilot valve in a closed state.
  • Fig. 2b is a detail view of the longitudinal cut through the yz-plane of the first embodiment of the inventive system with a pilot valve in a closed state.
  • Fig. 2c is a detail view of the longitudinal cut through the xz-plane of the first embodiment of the inventive system with a pilot valve in a closed state.
  • Fig. 3a is a longitudinal cut through the yz-plane of the first embodiment of the inventive system with a pilot valve in a second operating state.
  • Fig. 3b is a detail view of the longitudinal cut through the yz-plane of the first embodiment of the inventive system with a pilot valve in a second first operating state.
  • Fig. 3c is a detail view of the longitudinal cut through the xz-plane of the first embodiment of the inventive system with a pilot valve in a second operating state.
  • Fig. 4a is a longitudinal cut through the yz-plane of the second embodiment of the inventive system with a pilot valve in an initial first operating state.
  • Fig. 4b is top view on the second embodiment of the inventive system.
  • Fig. 5 is a longitudinal cut through the yz-plane of the second embodiment of the inventive system with a pilot valve in a closed state.
  • Fig. 6 is a longitudinal cut through the yz-plane of the second embodiment of the inventive system with a pilot valve in a second operating state.
  • Fig. 7a is a longitudinal cut through the yz-plane of the third embodiment of the inventive system with a pilot valve in an initial first operating state.
  • Fig. 7b is top view on the third embodiment of the inventive system.
  • the first embodiment of the inventive pneumatic actuator system comprises an actuator piston 1, which is arranged to be actuated by a working chamber 3.
  • the connection to a mechanical system that is actuated by the pneumatic actuator system is not shown.
  • a mechanical sys- tern could for example be a clutch system with a clutch rod connected to the actuator piston 1.
  • Such a clutch system is disengaged, or opened, by the actuator piston 1 that is driven by the working chamber 3 when it is pressurised to overcome the force from an actuator spring, i.e. a clutch spring, and to move the clutch rod to disengage the clutch via a clutch release bearing.
  • Fig. Ia shows the actuator piston 1 in a retracted position in which the working chamber 3 is in a depressurised state.
  • the actuator piston 1 and the working chamber 3 have essentially a rotational symmetry around the longitudinal axis z of the system.
  • the actuator piston 1 is slidably mounted inside a housing 5 and comprises an essentially cylindrical main body 7 and a disc-shaped head 9 which is fixed to the main body 7.
  • the diameter of the disc-shaped head 9 is larger than the diameter of the main body 7 such that the working chamber 3 is formed between the outer surface 11 of the main body 7, the working surface 13 of the head 9 and the inner surface of the housing 5.
  • the head 9 of the actuator piston 1 can slide inside a first cylindrical portion 15 of the housing 5.
  • An annular air tight first sealing means 16 between the radially outer surface of the head 9 of the actuator piston 1 and the inner surface of the first portion 15 of the housing 5 ensure that the working chamber 3 does not leak when the working chamber 3 is pressurised (see Fig. 3a) .
  • the main body 7 of the actuator piston 1 is able to slide inside a second cylindrical portion 17 of the housing 5, wherein the second portion 17 has a smaller diameter than the first portion 15.
  • An annular-shaped spacer 18 is attached to the outer surface of the main body 7 and is able to slide in contact with the inner surface of the second portion 17 of the housing 5 to keep the defined play during usage of the system.
  • the main body 7 of the actuator piston 1 has an inner hollow cavity in which the pilot valve is located.
  • the pilot valve is able to regulate the pressure in the working chamber 3.
  • the pilot valve itself comprises a pilot piston 19, a first valve member 21, and a pilot piston spring 23 between the pilot piston 19 and the first valve member 21 for biasing the pilot piston 19 against a control force.
  • the first valve member 21 is fixed to the inner surface of the main body 7 of the actuator piston 1.
  • the pilot valve is arranged in mechanical communication with the actuator piston 1.
  • Further parts of the pilot valve in this embodiment are a second valve member 25 and a valve spring 27, wherein the second valve member 25 is urged by the valve spring 27 towards the first valve member 21.
  • Fig. Ib shows a more detailed view of the pilot valve.
  • the main body 7 of the actuator piston 1 comprises three different channels for different air-flows.
  • an inflow channel 29 connects an outer air pressure supply 31 with the pilot valve.
  • the outer air pressure supply 31 is connected with an inlet opening 32 in the second portion 17 of the housing 5 via the defined play between the outer surface of the main body 7 of the actuator piston 1 and the inner surface of the second portion of the housing 1.
  • the inflow channel 29 allows an inflow 33 of air into the working chamber 3 when the pilot valve is in a second operating state (see Figs. 3a-c) .
  • an outflow channel 35 connects an exhaust opening 37 with the pilot valve.
  • the exhaust opening 37 is the open end of a longitudinal bore through the head 9 and the main body of the actuator piston 1.
  • the outflow channel 35 extends into the pilot valve by a radial bore to the hollow cavity of the main body 7 of the actuator piston 1 in which the pilot valve is located.
  • the outflow channel 35 allows an outflow 39 of air out of the working chamber 3 to the exhaust opening 37 as it is shown in Figs, la-c when the pilot valve is in a first operating state.
  • the third channel is a transport channel 41 between the working chamber 3 and the pilot valve along the direction of the x-axis (not visible Fig. Ia).
  • the transport channel 41 is visible in the detail view of the longitudinal cut through the xz-plane in Fig. Ic.
  • Fig. Ia the pilot piston spring 23 is relaxed and fully extended such that the pilot piston 19 is in an initial first position that is furthest away from the first valve member 21.
  • This initial first position of the pilot piston 19 corresponds to the first operating state of the pilot valve. In this first operating state of the pilot valve an outflow 39 of air from the working chamber 3 to an exhaust opening 37 is allowed.
  • control force is a pneumatic force in form of a pressure in a control chamber 43.
  • the pressure in the control chamber 43 is regulated by the control unit 45, wherein the control unit 45 comprises an inlet control valve 47 for pressurising the control chamber 43 and an outlet control valve 49 for depressurising the control chamber 43.
  • the inlet control valve 47 is connected to the air pressure supply 31 which is also connected to the inlet opening in the second portion of the housing 5 and the inflow channel 29. It should, however, be noted the pressure needed to operate the pilot valve is far below the pressure that is needed for operating the working chamber 3.
  • the inlet control valve 47 is able to regulate the control pressure to a desired value causing a desired effect on the pilot valve.
  • the inlet control valve 47 and the outlet control valve 49 can be ordinary and simple electric valves.
  • the control chamber 43 In the first operating state of the pilot valve as it is shown in Fig. Ia, the control chamber 43 is in a depressurised state.
  • the pneumatic control force i.e. the pressure in the control chamber 43, is in the first operating state of the pilot valve below a value which would suffice to urge the pilot piston 19 to compress the pilot piston spring 23.
  • Figs, la-c refer to a system wherein the pilot valve is in an initial first operating state in which the working chamber 3 is not in a pressurised state. However, Figs, la-c also refer to a system wherein the pilot valve has just reached the first operating state after preceding operation steps in which the working chamber 3 was pressurised. If the working chamber 3 is in a pressurised state when the pilot valve has just reached the first operating state, this results in an outflow 39 of air out of the working chamber 3 to the exhaust opening 37. Typically, the pressure inside the working chamber 3 is used to compress a clutch spring via a connected clutch rod (not shown) .
  • the clutch spring will urge the actuator piston 1 to move reducing the volume of the working chamber 3 until a balance of forces or a mechanical end stop is reached.
  • This movement of the actuator piston 1 is indicated by the motion arrow 51.
  • the first valve member 21 is in mechanical communication with the actuator piston 1, namely fixed to it, the movement of the actuator piston 1 influences the pilot valve. If the control chamber 43 is closed the movement of the actuator piston 1 and the first valve member 21 increases the force on the pilot piston spring 23. So, the movement of the actuator piston 1 itself increases the pressure in the control chamber 43, i.e. the control force.
  • control force reaches a value which is large enough to compress the pilot piston spring 23 until the pilot piston 19 reaches a closed position corresponding to a closed operating state of the pilot valve.
  • the closed operating state of the pilot valve When the closed operating state of the pilot valve is reached the movement stops due to the pressure that quickly builds up in the working chamber as soon as it is closed.
  • the system can therefore be regarded as self- regulating.
  • the closing of the control chamber 43 by means of the control unit 45 activates the self-regulating effect.
  • the first embodiment of the inventive system also comprises a position sensor 53 for sensing the actual position of the actuator piston 1 and/or the position of the pilot piston 19.
  • the position sensor 49 itself includes a sensor rod 55 and a sensor insert 57 with a central void 59 to receive the sensor rod 55.
  • the sensor rod 55 is fixed to the pilot piston 19 and extends longitudinally into the central void 59.
  • the sensor insert 57 is able to sense the position of the sensor rod 55 in the central void 59.
  • the sensor insert 57 itself projects into the hollow cavity of the main body 7 of the actuator piston 1 such that an independent - determination of the position of the actuator piston is possible.
  • the position sensor 53 is in communication with the control unit 45.
  • a regulation algorithm 61 may be fed with the information about the position of the actuator piston 1 and/or the position of the pilot piston 19 resulting in a certain regulation command that is transmitted to the control unit 45.
  • the regulation algorithm 61 can be implemented on a computing resource as part of the control unit 45 or, as shown, on an extra computing resource.
  • Fig. Ib shows the pilot valve in detail in a first operating state.
  • the first valve member 21, the second valve member 25 and the pilot piston 19 are arranged coaxially such that the first valve member 21 is arranged between the second valve member 25 and the pilot piston 19 when the pilot valve is in a first operating state.
  • the pilot piston spring 23 is relaxed and fully extended such that the pilot piston 19 is in a first initial and retracted position.
  • the pilot piston 19 has essentially the shape of a hollow tube that is open at the end facing towards the second valve member 25.
  • the inner volume of the tube forms an inner air channel extending from the front face of the pilot piston through the outflow channel 35 to the exhaust opening 37. It can be seen in Fig. Ia that the inner volume of the pilot piston 19 is in connection with the outflow channel 35 and therefore with the exhaust opening 37. It can be seen in Fig. Ic that the space around the pilot piston 19 in which the pilot piston spring 23 is located is in connected with the transport channel 41 in form of a radial bore in the direction of the x- axis through the main body 7 of the actuation piston 1.
  • the first valve member 21 has an annular shape having an inner opening with a diameter that is less than the diameter of the head of the second valve member 25.
  • the inflow channel 29 that is connected with the air pressure supply 31 is not connected with the transport channel 41 as long as the second valve member 25 is pushed in air tight sealing contact against the first valve member 21 by the valve spring 27. Therefore, there is no inflow 33 of air from the air pressure supply 35 to the working chamber 3 in the first operating state of the pilot valve .
  • Figs. 2a-c show the pilot valve in a closed state. Neither an inflow 33 nor an outflow 35 of air in or out of the working chamber 3 is allowed in this state.
  • the control force due to the pressure in the control chamber 43 is large enough to urge the pilot piston 19 against the pilot piston spring 23 to compress it.
  • the diameter of the head of the pilot piston 19 is less than the inner diameter of the first valve member 21, such that the front face of the pilot piston 19 is able to be biased through the inner opening of the first valve member 21 against the head of the second valve member 25.
  • An air tight sealing contact is achieved when the control force exceeds the spring force of the pilot piston spring 23 about a certain value. As long as this force excess is below the force needed to compress the valve spring 27, the closed state of the pilot valve is predominant.
  • Figs. 3a-c show the pilot valve in the second operating state. This state is reached by a control force that is triggered to increase by the control unit 45.
  • the inlet control valve 47 of the control unit 45 is directed to connect the air pressure supply 31 with the control chamber 43 to increase the pressure in a controlled manner.
  • the forces of a clutch spring and the corresponding pressure in the working chamber 3 can be magnitudes higher than the spring forces of the pilot piston spring 23 and the valve spring 27 control force and the corresponding control force.
  • An increase of the control force will therefore have no direct pressure effect on the actuator piston 1. But the pressure effect on the pilot valve is essential.
  • Pressurising the working chamber 3 has the effect that the force on a connected clutch rod and clutch spring increases.
  • the pressure quickly reaches a value large enough to compress the clutch spring to disengage the clutch via a clutch release bearing.
  • the disengaging coincides with a movement of the actuator piston 19 as indicated by motion arrow 51.
  • the second embodiment of Figs. 4a, b to 6 differs from the first embodiment described above only by the fact that the control force is transmitted mechanically.
  • the control unit 45 comprises an electric motor 63, wherein the control force of the electric motor is mechanically transferred to the pilot piston 19 by means of a cog wheel mechanism 65.
  • the electric motor 63 is preferably a step motor such that a position sensor 53 is not necessary. A position sensor 53 may, however, be implemented into the electric motor 63, if necessary.
  • the control of the ordinary electric motor 63 is very simple. Due to the self-regulating system the large and exact forces needed to operate the clutch can be achieved by a very simple steering of the ordinary electric motor 63.
  • Figs. 7a, b show a third embodiment of the invention, wherein the pilot valve is not located inside the main body 7 of the actuator piston 1. Instead, the pilot valve is connected laterally to the second portion 17 of the housing 5.
  • the longitudinal axis of the pilot valve extends along the direction of the y-axis.
  • the transport channel 41 takes the form of a tube connection between the working chamber 3 and the pilot valve, i.e. the space around the pilot piston 19 in which the pilot piston spring is located.
  • control force is pneumatic.
  • the control unit 45 regulates the pressure in the control chamber 43 control which acts on the pilot piston 19.
  • parts of the wall of the control chamber 43 are formed of the main body 7 of the actuator piston 1 and the pilot piston 19.
  • the pilot piston 19 will move coincidently with the actuator piston 1, because a movement of the actuator piston 1 influences the pressure in the control chamber 43.
  • the first valve member is fixed to a third portion 67 of the housing 5.
  • the third portion 67 of the housing 5 has essentially cylindrical hollow shape in which the pilot valve is located.
  • the longitudinal axis of the third portion 67 of the housing 5 extends along the direction of the y-axis.
  • the walls of the third portion 67 of the housing 5 comprise an inlet opening 32 for the inflow channel 29 and an exhaust opening 37 for the outflow channel 35.
  • the transport channel 41 extends from the working chamber 3 through the wall of the third portion 67 of the housing 5.
  • the volume of the third portion 67 of the housing 5 in which the pilot valve is located is also connected with the volume of the second portion 15 of the housing 5 in which the main body 7 of the actuator piston 1 is located and the control chamber 43 is formed. This connection provides the pneumatic communication between the actuator piston and the pilot valve, given that the control chamber 43 is closed.
  • the closing of the control chamber 43 by means of the control unit 45 activates the self- regulating effect.
  • a position sensor 53 may be provided for sensing the actual position of the actuator piston 1.
  • the position sensor 49 itself includes a sensor rod 55 and a sensor insert 57 with a central void 59 to receive the sensor rod 55.
  • the sensor rod 55 is fixed to the actuator piston 1 and extends longitudinally into the central void 59.
  • the sensor insert 57 is able to sense the position of the sensor rod 55 in the central void 59.
  • the position sensor 53 is in communication with the control unit 45.
  • a regulation algorithm 61 may be fed with the information about the position of the actuator piston 1 resulting in a certain regulation command that is transmit- ted to the control unit 45.
  • the regulation algorithm 61 can be implemented on a computing resource as part of the control unit 45.

Abstract

L'invention porte sur un système de vérin pneumatique de commande d'embrayage de véhicule comprenant:un piston de commande (1) actionné par la pression créée dans une chambre de travail (3), une soupape pilote régulant la pression dans la chambre (3), et une unité de commande (45) de la force appliquée. La soupape pilote comprend un piston (19), un premier élément (21) et un ressort (23) placé entre le piston (19) et le premier élément (21) et rappelant le piston (19) contre la force appliquée. La soupape pilote présente un premier état de fonctionnement, un deuxième état de fonctionnement et un état fermé, l'état de soupape dépendant de la force appliquée. L'invention se caractérise en ce que soupape pilote est en communication mécanique ou pneumatique avec le piston de commande (1) de manière telle que tout mouvement du piston de commande (1) rappelle la soupape pilote vers son état fermé.
PCT/EP2008/000540 2008-01-24 2008-01-24 Système de vérin pneumatique et sa méthode de commande WO2009092395A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015132233A1 (fr) * 2014-03-05 2015-09-11 Knorr-Bremse Systeme für Nutzfahrzeuge GmbH Amplificateur de force d'embrayage comprenant des moyens d'étanchéité dynamiques spécifiques disposés dans la zone de la tige de piston
WO2017208208A1 (fr) * 2016-06-02 2017-12-07 Kongsberg Automotive As Vanne destinée à être utilisée avec un système d'actionnement d'embrayage pneumatique

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1248914A (en) * 1967-12-04 1971-10-06 Dewandre Co Ltd C Improvements in or relating to boosted hydraulic systems
US4653382A (en) * 1985-04-03 1987-03-31 Nippon Air Brake Co., Ltd. Pull-type pneumatic booster
US6234290B1 (en) * 1998-08-06 2001-05-22 Mannesmann Sachs Ag Actuating installation for pneumatic clutch actuation with overload protection and/or incorrect-operation protection
WO2001050033A1 (fr) * 1999-12-29 2001-07-12 Kongsberg Automotive Asa Dispositif d'augmentation de la pression
US6419067B1 (en) 1999-07-21 2002-07-16 Luk Lamellen Und Kupplungsbau Beteiligungs Kg Pressure-medium-actuated clutch
WO2006006916A1 (fr) * 2004-07-13 2006-01-19 Scania Cv Ab (Publ) Detecteur de position pour mecanisme de vehicule

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1248914A (en) * 1967-12-04 1971-10-06 Dewandre Co Ltd C Improvements in or relating to boosted hydraulic systems
US4653382A (en) * 1985-04-03 1987-03-31 Nippon Air Brake Co., Ltd. Pull-type pneumatic booster
US6234290B1 (en) * 1998-08-06 2001-05-22 Mannesmann Sachs Ag Actuating installation for pneumatic clutch actuation with overload protection and/or incorrect-operation protection
US6419067B1 (en) 1999-07-21 2002-07-16 Luk Lamellen Und Kupplungsbau Beteiligungs Kg Pressure-medium-actuated clutch
WO2001050033A1 (fr) * 1999-12-29 2001-07-12 Kongsberg Automotive Asa Dispositif d'augmentation de la pression
WO2006006916A1 (fr) * 2004-07-13 2006-01-19 Scania Cv Ab (Publ) Detecteur de position pour mecanisme de vehicule

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015132233A1 (fr) * 2014-03-05 2015-09-11 Knorr-Bremse Systeme für Nutzfahrzeuge GmbH Amplificateur de force d'embrayage comprenant des moyens d'étanchéité dynamiques spécifiques disposés dans la zone de la tige de piston
CN106170637A (zh) * 2014-03-05 2016-11-30 克诺尔商用车制动系统有限公司 具有设置在活塞杆区域内的特别动力密封装置的离合器力放大器
RU2646768C1 (ru) * 2014-03-05 2018-03-07 Кнорр-Бремзе Зюстеме Фюр Нутцфарцойге Гмбх Усилитель привода управления сцеплением с расположенными на участке штока поршня специальными динамическими средствами уплотнения
CN106170637B (zh) * 2014-03-05 2018-11-13 克诺尔商用车制动系统有限公司 具有设置在活塞杆区域内的特别动力密封装置的离合器力放大器
WO2017208208A1 (fr) * 2016-06-02 2017-12-07 Kongsberg Automotive As Vanne destinée à être utilisée avec un système d'actionnement d'embrayage pneumatique

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