WO2009146737A1 - Actionneur linéaire - Google Patents

Actionneur linéaire Download PDF

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Publication number
WO2009146737A1
WO2009146737A1 PCT/EP2008/056854 EP2008056854W WO2009146737A1 WO 2009146737 A1 WO2009146737 A1 WO 2009146737A1 EP 2008056854 W EP2008056854 W EP 2008056854W WO 2009146737 A1 WO2009146737 A1 WO 2009146737A1
Authority
WO
WIPO (PCT)
Prior art keywords
linear actuator
nut
motor
actuator
extended
Prior art date
Application number
PCT/EP2008/056854
Other languages
English (en)
Inventor
Johannes Andrianus Maria Duits
Original Assignee
Ab Skf
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 Ab Skf filed Critical Ab Skf
Priority to PCT/EP2008/056854 priority Critical patent/WO2009146737A1/fr
Publication of WO2009146737A1 publication Critical patent/WO2009146737A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/06—Means for converting reciprocating motion into rotary motion or vice versa
    • 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
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • 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
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H2025/2062—Arrangements for driving the actuator
    • F16H2025/2075—Coaxial drive motors
    • F16H2025/2078—Coaxial drive motors the rotor being integrated with the nut or screw body
    • 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
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H25/22—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
    • F16H25/2204—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members with balls

Definitions

  • the present invention relates to a linear actuator device comprising an internally threaded tube and a hollow shaft motor encircling the threaded tube.
  • the internally threaded tube may comprise a plurality of cylindrical segments. The invention is especially advantageous when producing compact linear actuators.
  • Linear actuators are used to move an object along a straight line, either between two end points or to a defined position.
  • Actuators may be air or hydraulic driven using pressure or they may be driven by electricity.
  • Air or hydraulic driven actuators are cheap and simple in design. They are also easy to control, but they require an air or hydraulic supply which is relatively expensive, especially for small systems.
  • Electric driven linear actuators normally incorporate a rotating motor and some kind of transmission means to convert the relatively high-speed rotating motor to a low speed linear motion.
  • This transmission means may incorporate a gear box and/or a screw shaft.
  • One common type of linear actuator incorporates a screw shaft with a nut running thereon. The screw shaft extends over the full length of the actuator and sets the operating length of the actuator. Since the nut is held in a non-rotatable state, the nut will be displaced when the screw shaft is rotated by a motor.
  • the nut may incorporate rolling elements, such as balls or rollers, between the screw shaft and the nut. This will allow for a high efficiency actuator with high load transfer and long life.
  • the nut may also engage directly with the screw shaft, i.e. a sliding screw design.
  • the nut is preferably made of a plastic material.
  • One disadvantage of using a plastic nut is the relatively short life of the nut, due to wear caused by friction between the nut and the screw shaft.
  • the nut should be as short as possible in order to reduce friction and to allow for a long operating range.
  • the nut must be long enough to take up the applied forces. Even though this type of actuator is relatively cheap and well adapted for low and medium load cases, there is still room for improvements.
  • An object of the invention is therefore to provide an improved linear actuator that is compact in size.
  • a further object of the invention is to provide a linear actuator that is easy to control.
  • the object of the invention is achieved in that the linear actuator comprises a motor having a rotor fixedly attached to the internally threaded extended nut, and a stator fixedly attached to the housing, where the stator and the rotor are positioned around the extended internally threaded nut.
  • a linear actuator comprising an inner runner motor is provided. This is advantageous in that compact linear actuators can be obtained in an easy and cost-effective way.
  • the stator of the motor is integrated in the housing such that the stator will be a part of the housing. This is advantageous in that the size of the motor can be made as large as possible and in that the heat dissipation of the motor is improved.
  • the actuator comprises a rotational sensor adapted to measure the rotation of the extended nut.
  • the advantage of this is that the actuator can be controlled in an improved way, e.g. by setting different end stops for the piston.
  • the actuator comprises an internal control module. This is advantageous in that the control of the actuator is enhanced further.
  • the actuator comprises an anti-rotating device in the front end part of the actuator, adapted to prevent the piston from rotating around the centre axis of the actuator. This is advantageous in that the actuator does not have to be mounted to a non-rotating part of machinery in order to function properly.
  • Fig. 1 shows a cut view of a linear actuator according to the invention. MODES FOR CARRYING OUT THE INVENTION
  • Fig. 1 shows a first embodiment of a linear actuator device according to the invention.
  • the linear actuator 1 comprises a housing 2 with a front end part 3 and a rear end part 4. Inside the housing, a screw 5 having an external thread 6 runs in an extended nut 7 having an internal thread 8.
  • the housing 2 of the linear actuator 1 is symmetrical around a centre axis 18.
  • a piston rod 9 is at its inner end fixedly attached to the screw 5.
  • the piston rod 9 is provided with a front attachment means 20, e.g. a hole, a thread, a fork ear or a single ear, at its outer end.
  • the extended nut 7 comprises an internally threaded tube 12 in an outer support sleeve 13.
  • the extended nut is mounted to the housing in a rotatable way by means of a front bearing device 10, a rear bearing device 11 and an intermediate bearing device 14.
  • roller bearings are used as bearing devices to obtain a long service life and a reliable function.
  • Other bearing devices are possible to use, depending on e.g. required durability and precision.
  • the front bearing device 10 is mounted to the front end of the extended nut and the rear bearing device 11 is mounted to the rear end of the extended nut. In this way, the extended nut can rotate freely inside the housing.
  • the intermediate bearing device 14 is used to stabilize the extended nut and to support a motor.
  • the rear end part 4 may either extend just to the rear of the extended nut, or may comprise a control module as shown in Fig. 1.
  • the linear actuator When the linear actuator is to be used, it will be mounted to a rigid member in a known manner.
  • the part to be actuated is mounted to the front attachment means 20 of the piston rod in a non-rotatable way. This means that the piston rod will not be able to rotate around the centre axis of the linear actuator. Since the piston rod will not rotate, the screw will be driven along the extended nut when the extended nut rotates. In this way, the piston rod will extend out of or retract into the housing, depending on the rotational direction of the extended nut.
  • an anti-rotating device in the front end part of the actuator. This will allow the actuator to actuate parts that are not rigidly fixated in a non-rotatable way.
  • One way of providing an anti-rotating device is to give the piston and the front bushing 15 a shape that will not allow rotation. Other ways are also known and possible to use.
  • the screw 5 is in this example a friction screw with an external thread.
  • the length of the screw depends on e.g. the load that the linear actuator is designed for. A longer screw will be able to transfer a larger load to the internally threaded tube, but will also exhibit a larger friction.
  • the screw may also be of an external ball or roller screw type. By using one of these screw types, the friction between the screw and the extended nut will be reduced.
  • the extended nut is driven by an electric motor 16.
  • a motor that is mounted on the side of the extended nut instead of at the end of the extended nut is used.
  • a compact linear actuator is achieved, in which the length of the linear actuator device is in the same order of magnitude as the maximum piston stroke, i.e. the length of the motor will not reduce the piston stroke length of the actuator.
  • an actuator with substantially the same cross section measure as a pneumatic linear actuator is possible to obtain. In this way, the inventive actuator can replace a conventional pneumatic linear actuator without the need of adapting the mechanical interface.
  • a motor that can be mounted around the extended nut is a motor of the inner runner motor type.
  • the stator 23 with the windings is mounted fixedly to the housing 2 of the linear actuator.
  • the rotor 21 with the magnets 22 is fixedly mounted to the extended nut 7.
  • the rotor will thus be positioned between the extended nut and the stator of the motor.
  • the stator fixed to the linear actuator housing, the electrical power transfer to the stator coils is simplified since no rotational electric power transfer is necessary.
  • the heat transfer from the stator is improved.
  • an additional cooling of the motor is easily achieved since the heat originates from the coils in the stator.
  • One way to obtain a higher cooling capacity is to equip the housing with cooling fins, but also active cooling means are possible to use.
  • the stator is designed as an integral part of the housing. This is advantageous in that the stator can be made as large as possible, using the available outer measure of the actuator in an optimal way.
  • a compact linear actuator is achieved, in which the length of the linear actuator device is in the same order of magnitude as the maximum piston stroke, i.e. the length of the motor will not reduce the piston stroke length of the actuator.
  • the motor can extend along a substantial part of the length of the extended nut. Since the outer diameter of the stator is set by the size of the actuator housing, the power output of the motor can be adapted to the requirements by selecting the length of the motor. In one example, a motor extending over more than half of the length of the extended nut will provide the same output power as a conventional pneumatic linear actuator. In this way, a motor having a relatively high power output can be used in the actuator without an increase in the housing size.
  • the motor may be driven by an external or internal control unit.
  • the control unit may be any kind of suitable control unit, such as an analogue or digital control unit.
  • the linear actuator may have a standard PLC compatible l/O-interface using discrete signal lines or may have an integrated standard fieldbus interface. Most commonly, a standard PLC compatible l/O-interface will be used for the communication between the motor and the external PLC.
  • Two signal lines can be used for the commands "actuator out" and "actuator in”. These signals may be either low-level, when a separate power connection is provided, or high level, when the signals is used to drive the motor directly.
  • This input signal may also comprise information of the motor speed, i.e. how fast the motor should rotate. For a DC motor, this may be a voltage setting the speed or a modulated signal. For an AC motor, a modulated signal is suitable.
  • the actuator may also comprise an internal controller for the control of the motor, to interface to the position sensor and to communicate with the external controller, e.g. a PLC, via digital I/O lines, analogue lines or a fieldbus interface, e.g. CANbus, LIN bus, Profibus etc.
  • an internal control module 17 is mounted to the rear of the actuator.
  • the internal control module comprises in this embodiment the electrical interface, a microcontroller, a user interface and the rotational detector. This type of internal control module is possible to use if the length requirements for the actuator allows such a use.
  • control module may only comprise the rotational detector and an electrical interface.
  • Such a control module will be compact in size and may be integrated in a rear end part of the actuator. In this way, the actuator will have the same length as a conventional pneumatic linear actuator.
  • the linear actuator may also comprise two end position switches (not shown) that will set the end positions for the piston rod.
  • the end positions are fixed in the linear actuator, and the piston stroke is set by the length of the linear actuator.
  • the end position switches may also be adjustable, so that the piston stroke can be set by the user.
  • the end position switches may be connected to the internal or external control unit via two signal control lines, indicating the state of the linear actuator to the control unit.
  • the position states are either retracted or extended.
  • Another way of sensing the state of the linear actuator is to use a current sensing device measuring the current through the motor. When the motor is blocked, i.e. can not rotate, the current consumption of the motor will increase. This signal can be used to detect the state of the linear actuator, i.e. if the motor is blocked when the piston is in the outmost or inmost position. This detection method is suitable when the drive current and the blocking current for the motor differs enough, e.g. by a factor 2 or more.
  • the linear actuator is provided with a rotational sensor 19, detecting the rotations of the motor.
  • the sensor detects the rotation of the motor and outputs a signal representing a rotational value.
  • the sensor may either output an analogue value, e.g. a voltage proportional to the rotational speed of the motor, or a digital value, either a pulsed signal where the number of pulses is proportional to the rotational speed of the motor or a signal representing an absolute value for the rotation of the motor.
  • the absolute value may either represent a value for the angular position over one turn of the motor or may be an absolute value for the position of the piston over the full stroke length.
  • the internal control unit can count the number of turns in order to calculate the position of the piston.
  • a calibration possibility in the linear actuator, in order to be able to calibrate a starting value for the sensor. This may be e.g. an end position switch. During calibration, the piston is driven until the end position switch is reached, and the control unit starts to count from there.
  • an absolute output value When an absolute output value is used, it may consist of one part giving an absolute value for the angular position over one turn of the motor and one part representing the number of full turns rotated by the motor. In this case, a calibration possibility is not necessary but is still preferable, in order to be able to calibrate a starting value for the sensor.
  • the sensor is preferably a contactless rotational sensor, e.g. an optical or magnetic sensor, but also other types of sensors are possible to use, depending on e.g. required resolution, life time expectancy or cost.
  • the internally threaded tube 12 used in the extended nut 7 for the use in the above described linear actuator may be assembled from a plurality of tube segments.
  • the tube segments may resemble short tubular elements that are attached next to each other to form the elongated, internally threaded extended nut.
  • the extended nut may also be assembled from a plurality of longitudinal tube segments having longitudinal edges parallel to the centre axis of the internally threaded tube. Such a segment will represent a longitudinal split part of a tube, where the angular section is 180 degrees or less.
  • the extended nut may be made from either metal or plastic.
  • a plastic nut is used to run on an externally threaded metallic screw.
  • the wear of the nut will be high since the nut will wear over the whole range of the screw. Since this type of lead screw is open, it may not be permanently lubricated, but will have to be lubricated in regular intervals.
  • the wear of the extended nut will be reduced since the screw, preferably made of metal, will travel over the whole range but will only engage with each part of the internally threaded tube for part of the travel.
  • a lubricant e.g. oil or grease
  • This will allow for a permanently lubricated linear actuator.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Power Engineering (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)

Abstract

Dispositif actionneur linéaire (1) comprenant un boîtier (2), une vis à filetage externe (5), un piston (9) et un écrou long à taraudage interne (7). L'actionneur linéaire comprend un moteur (16) muni d'unrotor (21) relié fixe à l'écrou long à taraudage interne (7) et un stator (23) monté fixe sur le boîtier (2). Le stator (23) et le rotor (21) sont disposés atour de l'écrou long à taraudage interne (7). Cette invention offre l'avantage de pouvoir fabriquer des des actionneurs linéaires électriques compacts, facilement et rentablement.
PCT/EP2008/056854 2008-06-03 2008-06-03 Actionneur linéaire WO2009146737A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2008/056854 WO2009146737A1 (fr) 2008-06-03 2008-06-03 Actionneur linéaire

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2008/056854 WO2009146737A1 (fr) 2008-06-03 2008-06-03 Actionneur linéaire

Publications (1)

Publication Number Publication Date
WO2009146737A1 true WO2009146737A1 (fr) 2009-12-10

Family

ID=40555378

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2008/056854 WO2009146737A1 (fr) 2008-06-03 2008-06-03 Actionneur linéaire

Country Status (1)

Country Link
WO (1) WO2009146737A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103124862A (zh) * 2010-07-30 2013-05-29 Skf公司 线性促动器
CN103427539A (zh) * 2010-07-30 2013-12-04 Skf公司 线性促动器
CN108026763A (zh) * 2015-06-16 2018-05-11 特勒曼蒂克公司 用于阻流阀的致动器
WO2019057623A1 (fr) * 2017-09-20 2019-03-28 Continental Teves Ag & Co. Ohg Moteur électrique à arbre creux
CN109982894A (zh) * 2016-11-23 2019-07-05 Lg伊诺特有限公司 致动器、包括致动器的前照灯以及致动器控制方法
US11613239B2 (en) 2021-06-12 2023-03-28 Bwi (Shanghai) Co., Ltd. Pressure supply unit for a brake system of a vehicle

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4300512A1 (de) * 1993-01-12 1994-07-14 Bayerische Motoren Werke Ag Antrieb für eine Kraftstoffpumpe von Fahrzeugen
DE29917213U1 (de) * 1999-09-30 2001-02-15 Nimak Automatisierte Schweiste Roboterschweißzange
EP1089019A1 (fr) * 1999-09-30 2001-04-04 Eduard Bautz GmbH + Co. KG Actuateur linéaire
DE202005003981U1 (de) * 2005-03-12 2005-06-30 Elero Gmbh Antriebssystem

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4300512A1 (de) * 1993-01-12 1994-07-14 Bayerische Motoren Werke Ag Antrieb für eine Kraftstoffpumpe von Fahrzeugen
DE29917213U1 (de) * 1999-09-30 2001-02-15 Nimak Automatisierte Schweiste Roboterschweißzange
EP1089019A1 (fr) * 1999-09-30 2001-04-04 Eduard Bautz GmbH + Co. KG Actuateur linéaire
DE202005003981U1 (de) * 2005-03-12 2005-06-30 Elero Gmbh Antriebssystem

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103124862A (zh) * 2010-07-30 2013-05-29 Skf公司 线性促动器
CN103427539A (zh) * 2010-07-30 2013-12-04 Skf公司 线性促动器
CN103427539B (zh) * 2010-07-30 2016-04-13 Skf公司 线性促动器
CN108026763A (zh) * 2015-06-16 2018-05-11 特勒曼蒂克公司 用于阻流阀的致动器
EP3310995A4 (fr) * 2015-06-16 2019-01-30 Tolomatic, Inc. Actionneur pour soupape d'étranglement
US10536052B2 (en) 2015-06-16 2020-01-14 Tolomatic, Inc. Actuator for choke valve
CN108026763B (zh) * 2015-06-16 2020-10-09 特勒曼蒂克公司 用于阻流阀的致动器
CN109982894A (zh) * 2016-11-23 2019-07-05 Lg伊诺特有限公司 致动器、包括致动器的前照灯以及致动器控制方法
CN109982894B (zh) * 2016-11-23 2022-08-12 Lg伊诺特有限公司 致动器和包括致动器的前照灯
WO2019057623A1 (fr) * 2017-09-20 2019-03-28 Continental Teves Ag & Co. Ohg Moteur électrique à arbre creux
US11511721B2 (en) 2017-09-20 2022-11-29 Continental Teves Ag & Co. Ohg Electric hollow shaft motor
US11613239B2 (en) 2021-06-12 2023-03-28 Bwi (Shanghai) Co., Ltd. Pressure supply unit for a brake system of a vehicle

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