EP2998182A1 - Drive unit for a step of a rail vehicle, step unit, and rail vehicle with a step unit - Google Patents

Abstract

A drive unit (101) for a step (50) of a rail vehicle comprises a linear drive (120) with a housing (121) and a push rod (122) driven in an axial movement direction relative to the housing (121), and a telescopic guide (110) a relative to the housing (121) of the linear drive fixed outer bearing (111) and a relative to the outer bearing (111) in an axial direction of the telescopic guide (110) displaceable lifting rod (112). The lifting rod (112) is displaceable in the axial direction relative to the outer bearing (111) by means of the push rod (122) of the linear drive (120). The axial direction of movement of the push rod (122) is parallel to the axial direction of the telescopic guide (110). The lifting rod (112) is supported on the outer bearing (111) of the telescopic guide (110) to accommodate forces acting perpendicular to the axial direction.

Description

Technical area

The invention is in the field of rail vehicle technology and in particular relates to a drive unit for a tread of a rail vehicle. The invention also relates to a tread unit, as well as a rail vehicle with a tread unit.

Prior art

The DE 195 31 284 A1 describes a rail vehicle in which below a door a transverse to the carriage longitudinal axis displaceable control part is arranged. At the control part is acted upon by a first and second linear actuator tread surface hinged. The tread surface can be pivoted from a rest position located within the specified clearance gauge of the rail vehicle into a horizontal position which is at the same level as the vehicle floor of the rail vehicle.

EP 0 940 315 B1 describes a movable step for rail vehicles, which is designed as a folding stage and is opened by means of an electric motor against the force of a step acting on the tread in the retraction spring. An armature brake is provided for the electric motor to hold the folding stage in the open position without having to energize the electric motor.

The EP 1 826 063 A1 describes a transport vehicle having an access device movable relative to the chassis of the transport vehicle, which is moved between an extended position in which said access device is near a curb or a curb and a retracted position in which said access device has moved back under the vehicle chassis , is movable. The transport vehicle further comprises a transfer system for the access device, wherein the transfer system is filled with a gas and is movable in the manner of a bellows between a folded state and an opened state. The displacement system is connected to the access device such that the displacement system in its opened state, the access device in their brings out extended position and brings the access device in its retracted position in its folded state.

Disadvantages of the prior art

The previously known solutions for movable steps are sometimes very expensive and therefore prone to errors. For example, the tread of the leads DE 195 31 284 A1 a complicated pivoting movement through what is zeitaufendig and therefore only of limited use for local passenger transport. The drive units must therefore be designed according consuming.

The solution of EP 1 826 063 A1 on the other hand requires a complex pneumatic system and a pressure-tight bellows. However, this is susceptible to mechanical damage.

problem

It is therefore an object of the present invention to provide a drive unit for a step of a rail vehicle, which is robust and has a relatively simple structure.

Inventive solution

This object is achieved by a drive unit for example, a tread according to claim 1, by a tread unit according to claim 9, or by a rail vehicle according to claim 11. Other embodiments, modifications and improvements will become apparent from the following description and from the appended claims.

According to one embodiment, a drive unit, in particular for a tread of a rail vehicle, has a linear drive and a telescopic guide. The linear drive comprises a housing and a push rod driven in an axial direction of movement relative to the housing. The telescopic guide comprises a relative to the housing of the linear drive fixed outer bearing and a relative to the outer bearing in an axial direction of the telescopic guide displaceable lifting rod. The lifting rod is displaceable by means of the push rod of the linear drive relative to the outer bearing in the axial direction. The axial direction of movement of the push rod is parallel to the axial direction of the Telescopic guide, and the lifting rod is supported for receiving forces acting perpendicular to the axial direction on the outer bearing of the telescopic guide.

In the solution presented here, the actual drive and the mechanical fixation or force absorption are separated and are provided by different units. The telescopic guide serves to guide the lifting rod in the axial direction and to absorb the force acting on the lifting rod in the transverse or radial forces that occur in use of the tread, and to initiate the car body of the rail vehicle. The lifting rod is preferably held without play in the radial direction, wherein it is movable in the axial direction. The movement of the lifting rod can thereby be limited to a 1-dimensional movement in the axial direction.

In contrast to the telescopic guide, which absorbs the forces occurring when using the tread, the linear drive, however, has to absorb any external forces, since it only has the function to move the lifting rod in the axial direction. The linear drive can therefore be dimensioned smaller. The linear drive only has to apply a force which is sufficient to move the lifting rod together with the load-free tread on itself, possibly against an example mechanical return element. As a result, in contrast to the telescopic guide, only axial forces act on the linear drive.

In the solution presented here, moreover, no additional mechanical transmission elements are necessary, which must implement, for example, a linear movement of the linear drive in a rotary motion or pivoting movement. As a result, the use of material and thus the weight can be reduced. In addition, this improves the reliability of the drive unit, so that the drive unit can also be used under harsh environmental conditions.

The drive unit can therefore be regarded as a direct drive, since the linear movement of the linear drive is converted directly into the movement of the tread.

The linear drive can for example be attached to the outer bearing of the telescopic guide and be supported by this. Specifically, the housing of the linear drive can be fixed directly to the outer bearing of the telescopic guide or rigidly via corresponding retaining elements. The drive unit can then be used as a preassembled unit be provided for attachment to the car body. The drive unit may be detachably connected to the carbody or load-bearing structures to ensure easy interchangeability.

It is also possible that the linear drive and the telescopic guide are each fastened individually, for example on the car body or load-bearing structures which are fixed to the car body. In any case, the linear drive is fixed relative to the outer bearing of the telescopic guide and thus allows movement of the lifting rod relative to the outer bearing.

Preferably, the drive unit is used for realizing the entry stroke for the driver, without being limited thereto.

The linear drive is preferably an electric adjusting element, as a result of which complicated pneumatic or hydraulic drives are avoided. The linear drive can for example have a defined stroke in the axial direction of movement, wherein it can continue to allow for the push rod fixed predetermined holding positions or holding positions at any position in the axial direction of movement.

The telescopic guide does not have to be closed, but can also be partially open. The outer bearing of the telescopic guide, for example, comprise two mutually axially spaced plain bearings, which allow only a movement in the axial direction. These plain bearings can then be provided with corresponding attachment interfaces for attachment to the car body, or to load-bearing structures fixed to the car body.

Alternatively, the outer bearing may also be a linear bearing, for example a linear plain bearing or a linear ball bearing.

Regardless of the specific configuration of the outer bearing, the telescopic guide, typically the outer bearing, corresponding mounting interfaces for attachment to the car body or load-bearing structures that are fixed to the car body, on. The attachment interfaces are dimensioned so that they can initiate the forces occurring when using the tread in the car body or the load-bearing structures.

The forces occurring during use of the tread lead in particular to tilting moments, which act on the outer bearing. The outer bearing and the mounting interfaces should therefore have sufficient dimensions and strength to safely initiate these tilting moments in the car body or the load-bearing structures.

The linear drive and the telescopic guide are typically arranged one behind the other in the axial direction, and the axial direction of movement of the push rod and the axial direction of the telescopic guide, i. the direction of movement of the lifting rod, are parallel to each other. Preferably, the push rod and the lifting rod are arranged coaxially with each other, since other than axial forces are avoided in the interaction of push rod and lift rod.

However, a strict coaxial arrangement is not necessary. For example, a linear drive can simultaneously drive the lifting rods of two telescopic guides arranged parallel to one another. By increasing the number of telescopic guides they can be made smaller, which can have an advantageous effect on the total weight.

According to one embodiment, the linear drive and the telescopic guide - with respect to the respective extension and retraction direction and with respect to a normal operating position of the rail vehicle - mounted substantially in a horizontal manner under the floor of the car body. Thus, the movement of the push rod of the linear drive and the lifting rod of the telescopic guide during extension and retraction takes place substantially in a horizontal direction. Accordingly, the axial direction of movement of the push rod and the axial direction of the telescopic guide extend horizontally or horizontally, in particular substantially parallel to the floor of the rail vehicle.

The push rod and the lifting rod can be connected to each other. But it is also possible that the push rod presses only dull against a push rod facing the end of the lifting rod. In this case, the linear drive only serves to "extend" the lifting rod. The "retracting" then takes place by a restoring element, which acts on the lifting rod and this pushes back together with the push rod.

According to one embodiment, the outer bearing of the telescopic guide is an outer tube, which guides the lifting rod axially, wherein the push rod of the linear drive engages in the axial direction of the telescopic guide in the outer tube and moves the lifting rod in the outer tube. The telescopic guide can thus be formed for example in the form of a telescopic tube.

According to one embodiment, the outer tube has at least one sliding bearing on an end facing away from the linear drive end, which holds the lifting rod radially substantially free of play, leads in the axial direction and receives radially acting on the lifting rod forces.

The plain bearing can be, for example, consisting of two bearings plain bearing. The sliding bearing does not necessarily prevent rotation. However, it should allow virtually a backlash-free and load-bearing storage in the radial direction.

The specific design of the sliding bearing depends inter alia on the cross section of the lifting rod. This may have a circular outer cross section according to one embodiment. An approximately rectangular cross-section, for example with rounded corners, is also possible.

According to one embodiment, the telescopic guide comprises a restoring element, which counteracts a movement of the lifting rod during its displacement by the push rod.

The restoring element may be, for example, a mechanical return element, for example in the form of a force accumulator. The return element serves to return the lifting rod and the push rod to their original position, i. retract the tread. The linear drive must therefore be designed only for one direction of movement. The provision is made via the return element, which stores the energy required for this purpose, for example in a spring element, which is tensioned by the movement of the push rod.

The restoring element can be integrated, for example, in the telescopic rod, for example between outer bearing and lifting rod. It is also possible to provide the return element on the outside of the outer bearing or separately to the telescopic guide.

According to one embodiment, the linear drive comprises an electromechanical holding brake to hold the push rod in any position. This allows the position of the tread to be chosen arbitrarily. In addition, so the push rod can be kept against the action of the return element. The linear drive can then be switched off.

In a preferred embodiment, the electromechanical holding brake is configured such that the push rod is held in the extended position of the tread. The end position of the drive can be detected by an overcurrent detection by the to be overcome by the linear drive resistance is too large. For predetermining the extended position, a predefined tension of the restoring element can be set in the extended position. Alternatively, a stop may be provided, against which the push rod abuts in the extended position.

By the return element, the lifting rod counteracts the push rod and would push back the push rod, if either the electromechanical holding brake would not be present, or the linear drive is not de-energized.

However, a return element can be dispensed with if the linear drive can securely hold the push rod in a predetermined position.

According to one embodiment, the linear drive and / or the telescopic guide on a sensor for detecting a maximum allowable displacement of push rod and / or lifting rod. Thus, a maximum permissible displacement can be detected and thus the movement can be limited.

According to one embodiment, the linear drive and / or the telescopic guide on a Endlagerschalter for detecting the correct return of push rod and / or lifting rod. This can ensure that in particular the lifting rod is completely returned to its original position and the tread is completely retracted again.

According to one embodiment, the drive unit further has a control unit, which is connected to the linear drive and controls the linear drive. The control unit may also be connected to the repository switch and the sensor and detect and evaluate their output signals. The control unit can Have at least one communication interface for data exchange with higher-level control units of the rail vehicle.

According to one embodiment, a tread unit on at least one drive unit and a tread, which is rigidly connected to the lifting rod of the drive unit and which is movable by moving the lifting rod in the axial direction of the telescopic guide.

The tread is guided by the drive unit in a linear movement and in particular led out laterally from the boundary profile of the rail vehicle and returned again.

The arrangement of the tread unit can be carried out according to a further embodiment such that the linear drive and telescopic guide are arranged substantially horizontally aligned under the floor of the car body. The movement during extension and retraction of the treads thus takes place substantially in the horizontal direction, or in the axial direction.

According to one embodiment, the tread unit on at least two drive units, which are arranged parallel to each other, wherein the tread rigidly connects the lifting rods of the two drive units together.

The drive units may, according to one embodiment, preferably be designed such that a drive unit is sufficient for actuating the tread unit. The power of a drive unit is preferably sufficiently large to extend the tread against the action of all return elements. Accordingly, provided electromechanical holding brakes may be designed such that a holding brake is sufficient to keep the tread unit in the extended position.

This enables a redundancy of the drive. In addition, the tread is held by two spaced apart telescopic guides.

The tread is arranged in the extended state outside of the rail vehicle, that projects beyond the boundary profile of the rail vehicle. When retracted, the tread, ie its outwardly facing side, directly adjoins the boundary profile and may form part of the outside of the rail vehicle.

When retracted, the function of the tread is not visible from the outside.

According to one embodiment, a rail vehicle comprises a car body, at least one door and a tread unit, wherein the one or more outer bearing of the telescopic guide or the telescopic guides are attached to the car body.

characters

• Fig. 1 zeigt ein Schienenfahrzeug gemäß einer Ausführungsform der Erfindung.
• Fig. 2 zeigt eine Schnittansicht entlang eines Teilbereichs der Linie AA in Fig. 1.
• Fig. 3 zeigt eine Schnittansicht entlang der Linie CC in Fig. 2.
• Fig. 4 zeigt eine Trittstufeneinheit mit zwei Antrieben gemäß Ausführungsformen der Erfindung.
• Fig. 5A bis 5C zeigen verschiedene Ausführungsformen von Teleskopführungen.

The accompanying drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention. The elements of the drawings are relative to one another and not necessarily to scale. Like reference numerals designate like parts.

• Fig. 1 shows a rail vehicle according to an embodiment of the invention.
• Fig. 2 shows a sectional view along a portion of the line AA in Fig. 1 ,
• Fig. 3 shows a sectional view taken along the line CC in Fig. 2 ,
• Fig. 4 shows a tread unit with two drives according to embodiments of the invention.
• Figs. 5A to 5C show various embodiments of telescopic guides.

embodiments

Hereinafter, the invention will be described by means of embodiments, without being limited thereto.

Fig. 1 shows a rail vehicle 10 with a tread unit 100 according to an embodiment. The tread unit 100 is arranged below the passenger door 15 closest to the driver's seat. The tread unit 100 is used according to the present embodiment, the driver to allow entry and exit from the rail vehicle 10 outside of stations. However, the invention is not limited thereto, but can also be applied to treads for passengers. In the present embodiment, the tread is at a certain distance arranged below the floor 14 of the rail vehicle, since the tread does not serve for the exit to a platform but for the exit on, for example, free route.

Fig. 2 shows a section along the in Fig. 1 indicated line AA. The tread unit 100 comprises a linear drive 120 and a telescopic guide 110, which are arranged coaxially with each other. The telescopic guide 110 is attached to the body 13 of the rail vehicle 10, so that the force acting on the tread 50 forces can be absorbed by the car body 13. By contrast, the linear drive 120 does not have to absorb any appreciable forces, since there is a separation between the drive and the bearing.

Fig. 2 shows the tread unit 100 in the retracted and extended state. In the retracted state, the tread 50 of the tread unit 100 is within the permissible boundary profile 12 of the rail vehicle 10. The tread 50 can form part of the outer contour of the rail vehicle 10 thereto. In this case, the tread 50 may have a panel which is flush with the surrounding outer contour of the rail vehicle 10, so that an aerodynamically substantially closed outer contour is formed.

The telescopic guide 110 and the linear drive 120 are each individually on the car body 13 or attached to load-bearing structures that are fixed to the car body. As in Fig. 2 can be seen, the attachment can be designed so that the telescopic guide 110 and the linear actuator 120 - are arranged substantially horizontally with respect to their axial movement direction during extension and retraction -. The tread 50, and thus also the push rod 122 and the lifting rod 112 move according to Fig. 2 essentially in a horizontal direction, especially in the axial direction.

Fig. 2 shows that the telescopic guide partially extends into an opening in the car body and, when the lifting rod is extended, the tread 50 brings to a position outside the boundary profile 12.

The tread 50 may have at its end facing the car body 13 a stop 51 to define the end position of the tread 50 in the retracted state relative to the car body.

Fig. 2 further shows that the tread 50 is spaced below the floor 14 of the rail vehicle. This makes it easier for the driver to enter or exit the open track. The tread 50 is therefore located below the platform edge and would not be used when stopping at a platform with platform edge at the level of the floor 14 in the door area 15.

Fig. 3 shows a tread unit comprising two drive units, each with a linear drive 120 and a telescopic guide 110. The push rods 122 of the linear drives 120 are removed in the fully retracted state of the lifting rods 112 and engage, when extending, in the outer bearing 111 of the respective telescopic guide 110, which here in Formed a pipe, a.

Visible are also provided in the car body 13 openings 17 through which reach through the telescopic guides 110.

Fig. 4 FIG. 2 illustrates a sectional view through a tread unit 100, which comprises two drive units 101 arranged parallel to one another. The two drive units 101 are constructed identically in the present embodiment.

The outer bearing 111 of the telescopic guide 110 is designed in the present embodiment as a tube which has a sliding bearing 114 at its end remote from the linear drive 120. This sliding bearing 114 axially guides the lifting rod 112 and holds it radially. The lifting rod 112 in turn has at its end facing the linear drive 120, a sliding shoe 113, which is axially slidably supported radially on the inner wall of the tubular outer bearing 111 and thus also supports the lifting rod 112 radially and axially. The inner wall of the tubular outer bearing 111 forms a sliding bearing for the sliding shoe 113.

The outer bearing 111 of the telescopic guide 110 is fixed to the car body 13. The housing 121 of the linear drive 120 is likewise fastened to the carriage body 13, so that the housing 121 of the linear drive 120 is fixed relative to the outer bearing 111 of the telescopic guide 110. Alternatively, the housing 121 may also be attached directly to the outer bearing 111.

By means of the shoe 113 and the sliding bearing 114, the occurring and acting on the lifting rod 112 tilting moments are absorbed by the outer bearing 111 and not shown here mounting interfaces in the Car body 13 initiated. The attachment interfaces may be, for example, clips connected integrally to the outer bearing or outer tube 111. It is also possible if the outer bearing or outer tube 111 individual load-absorbing structures, such as side members, passes through and is welded to these.

The push rod 122 of the linear actuator 120 is arranged coaxially with the lifting rod 112 and pushes it towards the front slide bearing 114. This is the arrows in Fig. 4 indicated.

The telescopic guide 110 may have a mechanical restoring element, not shown here, which is arranged, for example, within the outer bearing 111 and is supported between the outer bearing 111, specifically, for example, the sliding bearing 114, and the lifting rod 112, specifically, for example, the sliding shoe 113. The reset element acts with the arrow in Fig. 4 indicated movement of the push rod 122 against. The push rod 122 therefore performs work against the return element and supplies this energy, which stores the return element and to return the lift rod 112, and thus the push rod 122 uses. In the simplest case, the restoring element is a spring element. Alternatively, the return element may also be a pneumatic return element.

If the restoring element is a spring element, the telescopic guide 110 can also be referred to as a spring tube.

The two lifting rods 112 are rigidly connected to the tread 50 at their front, remote from the respective linear drive 120 end. The tread 50 may, for example, comprise a bridge which establishes the actual rigid connection between the two lifting rods 112. A tread can then be connected to the bridge. In addition, the bridge may carry a part of the outer lining of the rail vehicle in the form of a panel.

The tread unit 100 further comprises a control unit 140, a repository switch 123 and a holding brake 124. The holding brake 124 serves to hold the push rod 122 in a preferably arbitrary position against the return action of the return element. As a result, the linear drive 110 can be de-energized when the holding brake 124 is actuated.

By means of the repository switch 123, however, it is checked whether the push rod 122 has been completely retracted, in order to ensure that the tread 50 is completely within the boundary profile 12 and the onward travel of the rail vehicle can be released. The control unit 140 can for this purpose have a communication interface for communication with higher-level control units.

The repository switch 123 may also be provided in the telescopic guide 110 to directly detect the position of the lifting rod 112. This is particularly advantageous if the lifting rod 112 and the push rod 122 are not firmly connected.

The tread unit 100 may further comprise a sensor which detects the position of the lifting rod 112 and / or the push rod 122, so as to determine the current position of the tread 50. Thus, the extension of the tread 50 can be set to different positions. The maximum position can also be determined by detecting the current which is supplied to the linear drive 120, since an overcurrent flows here when a mechanical resistance is reached by the linear drive 120. The sensor can therefore also be an overcurrent sensor.

The drive units 101 can be used as a direct drive for the realization of the step for the driver, taking into account critical environmental conditions, in particular the boundary profile 12.

The tread unit 100 may have in particular the control unit 140, two drive units 101 each having a linear drive 120, for example in the form of an electric adjuster with holding brake 124 and limit switch 123, and a telescopic guide 110 with mechanical reset unit, and the tread 50. It is also possible that only one drive unit 101 and one additional telescopic guide 110 are used, since for the extension of the tread 50 no large axial forces must be applied. The two telescopic guides 110 then serve to accommodate the tilting moments.

By actuating a switching element, linear drive 120 drives out the push rod 122, which thereby axially displaces the lifting rod 112. At the same time a biasing member acting on the lifting rod 112 is biased. The tread 50 moves out at the same time.

An overcurrent detection of the linear drive 120 detects the end position and or possible foreign bodies in the effective range of the linear drive 120 and / or the tread 50. The electromagnetic holding brake 124 is actuated and the linear drive 120 can be de-energized. The step 50 is in the "extended" position.

To "retract" the tread 50, the supply voltage of the holding brake 124 is turned off, whereby the holding function of the holding brake 124 is terminated. By means of the return element, the lifting rod 112, the push rod 122 and thereby also the tread 50 are retracted. About the limit sensor 123, the end position is detected and the signal is given to the control unit 140.

The tread unit may be redundant for safety reasons, i. Two drive units 101 are used. The mechanical connecting element for the lifting rods 112 is the step 50, whereby the movement of both drive units 101 takes place synchronously and the movement of a drive unit by means of the step 50 is also transmitted to a possibly failed drive unit. If, for example, a restoring element fails, the provision of both drive units 101, specifically the lifting rod 112 and the push rod 122, nevertheless takes place.

The safe return of the tread 50 is done in total by the or the restoring elements, which are separate to the linear actuators 120.

The position "safe retraction" can be detected via the repository switch 123 or other sensors, which are provided for example on the linear drive 120.

The realization of the redundancy takes place via the installation of a second linear drive and the appropriate dimensioning of each return element for both drive units 101.

Figs. 5A to 5C show various embodiments of telescopic guides. Fig. 5A shows an embodiment of a telescopic guide 110a with approximately rectangular cross-section with rounded corners of lift rod 112a and outer bearing 111a, which is present here as a pipe. Fig. 5B on the other hand shows an embodiment of a telescopic guide 110b approximately round and in particular circular cross-section of lifting rod 112b and outer bearing 111b, which is also present here as a pipe. The lifting rods of in Figs. 5A and 5B embodiments shown are mounted by means of corresponding slide bearing (not shown) on the outer bearing.

Fig. 5C on the other hand shows an embodiment in which the lifting rod 112c is a partially open profile and is supported by running balls 118 or rollers against the inner wall of the tubular outer bearing 111c.

The above-described embodiments may be arbitrarily combined with each other. While specific embodiments have been illustrated and described herein, it is within the scope of the present invention to properly modify the illustrated embodiments without departing from the scope of the present invention. The following claims are a first, non-binding attempt to broadly define the invention.

LIST OF REFERENCE NUMBERS

10

track vehicle

12

clearance gauge

13

car body

14

floor

15

door area

17

opening

50

tread

51

attack

100

Tread unit

101

drive unit

110, 110a, 110b, 110c

Telescopic guide / spring tube / telescopic tube

111, 111a, 111b, 111c

Satellite camp / outer tube

112, 112a, 112b, 112b

lifting rod

113

shoe

114

bearings

115

inner space

118

Running balls / rollers

120

linear actuator

121

casing

122

pushrod

123

repository switch

124

holding brake

140

control unit

Claims (11)

Drive unit (101), in particular for a step of a rail vehicle, comprising: a linear drive (120) having a housing (121) and a push rod (122) driven in an axial movement direction relative to the housing (121): a telescopic guide (110) having a peripheral bearing (111) fixed relative to the housing (121) of the linear drive and a lifting rod (112) displaceable relative to the outer bearing (111) in an axial direction of the telescopic guide (110), - wherein the lifting rod (112) by means of the push rod (122) of the linear drive (120) relative to the outer bearing (111) is displaceable in the axial direction, - The axial direction of movement of the push rod (122) is parallel to the axial direction of the telescopic guide (110), and - Wherein the lifting rod (112) for receiving perpendicular to the axial forces acting on the outer bearing (111) of the telescopic guide (110) is supported. Drive unit according to claim 1, wherein the outer bearing (111) of the telescopic guide (110) is an outer tube, which guides the lifting rod (112) axially, and wherein the push rod (122) of the linear drive (120) in the axial direction of the telescopic guide (110) in the Outer tube (111) engages. Drive unit according to claim 2, wherein the outer tube (111) has at least one sliding bearing (114) at an end facing away from the linear drive (120), which holds the lifting rod (112) radially substantially free of play, in the axial direction and radially on the lifting rod ( 112) absorbs acting forces. Drive unit according to one of claims 1 to 3, wherein the telescopic guide (110) has a return element, which counteracts a movement of the lifting rod (112) during its displacement by the push rod (122). Drive unit according to one of claims 1 to 4, wherein the linear drive (120) comprises an electromechanical holding brake to hold the push rod (122) in any position, in particular in an extended position. Drive unit according to one of claims 1 to 5, wherein the linear drive (120) and / or the telescopic guide (110) has a sensor for detecting a maximum allowable displacement of push rod (122) and / or lifting rod (112). Drive unit according to one of claims 1 to 6, wherein the linear drive (120) and / or the telescopic guide (110) has a repository switch for detecting the correct return of push rod (122) and / or lifting rod (112). Drive unit according to one of claims 1 to 7, further comprising a control unit (140) which is connected to the linear drive (120) and drives the linear drive (120). Tread Unit (100), comprising: - At least one drive unit (101) according to one of claims 1 to 8, and - A tread (50) which is rigidly connected to the lifting rod (112) of the drive unit (101) and which by moving the lifting rod (112) in the axial direction of the telescopic guide (110) is movable. Tread unit (100) according to claim 9, wherein the tread unit (100) at least two drive units (101) which are arranged parallel to each other, wherein the tread (50) rigidly connects the lifting rods (112) of the two drive units together. Rail vehicle, comprising: - a car body (13); - at least one door (15); and - A tread unit (100) according to any one of claims 9 or 10, wherein the one or more outer bearing (111) of the telescopic guide or the telescopic guides (110) on the car body (13) are attached.

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