Linearantrieb

Abstract

Linear drive for providing linear motion, comprising a profile arm (2) extending along an axis of motion (8) and a guide arrangement (3) arranged linearly movable along the axis of motion (8) on the profile arm (2), the guide arrangement comprising a gear mounted for rotation, and a toothed belt (5) extending along the axis of motion (8), which partially wraps around the gear and is fixed at each end to the profile arm (2), wherein the profile arm (2) has a guide recess (82) extending along the axis of motion (8), in which at least one guide surface (107, 108, 109, 110) is formed for a linearly movable bearing of the guide arrangement (3), wherein the guide arrangement (3) comprises at least one guide element (85, 86) that engages in the guide recess (82) and rests on the guide surface (107, 108, 109, 110). lieswherein at least one connection opening (96) is formed on an outer surface (95) of the guide arrangement (3) and wherein at least one outlet opening (97) is formed on an inner surface (103) of the guide arrangement (3) facing the guide recess (82), wherein the guide arrangement (3) is penetrated by at least one fluid channel (98) between the at least one connection opening (96) and the at least one outlet opening (97), characterized in that a cover strip (83) is associated with the profile extension (2), which extends with a longest edge parallel to the axis of movement (8) and which covers the guide recess (82).

Description

[0001] The invention relates to a linear drive for providing a linear motion, comprising a profile arm extending along an axis of motion and a guide arrangement arranged linearly movable along the axis of motion on the profile arm, the guide arrangement comprising a rotaryally mounted gear, a toothed belt extending along the axis of motion which partially wraps around the gear and which is fixed at each end to the profile arm, wherein the profile arm has a guide recess extending along the axis of motion in which at least one guide surface for a linearly movable bearing of the guide arrangement is formed, wherein the guide arrangement comprises at least one guide element which engages in the guide recess and rests on the guide surface.wherein at least one connection opening is formed on an outer surface of the guide arrangement and wherein at least one outlet opening is formed on an inner surface of the guide arrangement facing the guide recess, wherein the guide arrangement is penetrated by at least one fluid channel between the at least one connection opening and the at least one outlet opening.

[0002] DE 29919550 U1 describes a linear drive, designated as an Omega drive, in which a toothed belt partially encircles a gear of a drive motor and is held in a defined position relative to the gear by associated tensioning rollers. Furthermore, a turnbuckle is provided for clamping one of the ends of a toothed belt, comprising a first plate with teeth for engaging the tooth gaps of the toothed belt and a second plate for supporting the back of the toothed belt, with a web associated with the end of the toothed belt that joins the two plates together in one piece.

[0003] From DE 10 2010 019 681 A1, a linear motion device with a housing and a carriage movable in a longitudinal direction relative to the housing is known, wherein the housing extends in the longitudinal direction with a substantially constant U-shaped cross-sectional form, such that the housing defines a guide cavity, wherein the guide cavity is covered with a toothed belt extending in the longitudinal direction, wherein the toothed belt is attached to the housing at both ends so that it defines a toothed belt plane, wherein at least one separate guide rail extending in the longitudinal direction is arranged within the guide cavity, on which at least one separate guide carriage is mounted for longitudinal movement and is rigidly connected to the carriage, wherein a first and a second deflection wheel are rotatably attached to the carriage, which deflect the toothed belt out of the toothed belt plane.wherein a rotatable drive wheel is arranged between the first and second deflection pulleys, which is in drive engagement with the toothed belt.

[0004] US Patent 2004 / 0131289A1 discloses a rodless pneumatic actuator having a first and second longitudinally extending chamber, wherein a piston arrangement is arranged in the first chamber and wherein a sliding arrangement is arranged in the second chamber.

[0005] DE 11 2014 002 700 T5 discloses a threaded spindle drive in which the threaded spindle is housed in a casing with removable side walls and a flexible top surface cover.

[0006] The object of the invention is to provide a linear drive that has an improved range of functions in a compact design.

[0007] This problem is solved for a linear drive of the type mentioned above with the features of claim 1.

[0008] The fluid channel extending between the connection opening and the outlet opening allows for the supply of a pressurized fluid, such as compressed air, or a vacuum at the outlet opening. This enables either positive or negative pressure to be applied to the guide recess. Positive pressure is advantageous when the linear actuator is to be used in an environment where there is a risk of dirt ingress into the guide recess. By supplying pressurized fluid through the fluid channel into the guide recess, a fluid flow and thus positive pressure can be generated within the recess, counteracting the ingress of dirt.In contrast, applying a vacuum to the guide recess is advantageous when the linear actuator is to be used in an environment where the release of particles due to relative movement between the profile arm and the guide assembly is undesirable. This might be the case, for example, when using the linear actuator in a cleanroom where the ambient air surrounding the linear actuator has a high degree of purity that should not be compromised by abrasion or other sources of contamination resulting from the relative movement between the profile arm and the guide assembly. In this case, a vacuum device, such as a vacuum pump, is connected to the connection opening. This device creates a vacuum at the outlet, allowing particles released between the guide assembly and the profile arm to be extracted and transported away through the fluid channel.By way of example, the guide arrangement is provided to have a support structure consisting of a base plate and a parallel support plate, and the fluid channel optionally passes through either the base plate or the support plate. Furthermore, by way of example, the connection opening is provided to be located away from the guide recess, in particular on an outer surface of the guide arrangement opposite the guide recess, in order to offer an easily accessible connection point for a fluid line to be connected at the connection opening.

[0009] It is advantageous for the guide arrangement to have a first guide element and a second guide element, which are spaced apart from each other along the axis of movement, and for at least one opening to be arranged between the two guide elements. The function of the guide elements is to enable a sliding or rolling motion between the guide arrangement and the at least one guide surface of the profile boom. By way of example, at least one sliding element or at least one rolling element of the respective guide element rests on the at least one guide surface, whereby the relative mobility between the profile boom and the guide arrangement is ensured by a sliding or rolling motion of the sliding element or rolling element on the guide surface.By using two guide elements spaced apart along the axis of movement, an advantageous, and in particular, low-backlash and stable linearly movable connection between the profile boom and the guide assembly can be achieved. It is further advantageous if the (in particular, only) outlet opening is located between the two guide assemblies. This ensures, especially in the case of a vacuum in the fluid channel, the effective removal of particles released during the relative movement between the guide assembly and the profile boom. It is particularly advantageous if the fluid channel has additional outlet openings besides the one between the two guide elements to ensure a uniform fluid supply or vacuum in the vicinity of the guide elements.

[0010] According to the invention, a cover strip is provided for the profile arm, the longest edge of which extends parallel to the axis of movement and which at least partially covers the guide recess. The cover strip significantly reduces contamination of the guide recess by dirt from the vicinity of the linear drive or the release of particles due to the relative movement between the profile arm and the guide arrangement, in addition to the effect of pressurization or vacuum application to the guide recess. This is particularly true when the cover strip achieves extensive, and especially nearly complete, coverage of the guide recess.Preferably, the cover strip is designed as a thin metal or plastic strip, the longest edge of which has at least approximately the same length as the length of the profile extension along the axis of movement, and whose width is selected to be at least approximately the extent of the guide recess transverse to the axis of movement. The thickness of the cover strip is chosen such that it can be elastically deformed with a small bending radius around a bending axis oriented transverse to the axis of movement. Additionally, a magnetic strip extending along the axis of movement can be attached to the edge of the guide recess, enabling a sealing adhesion of the cover strip, which is made of a magnetizable metal material and is manufactured as a thin metal strip, to the profile extension. Preferably, such magnetic strips are provided on both sides of the guide recess.

[0011] Additionally, it may be provided that the fluid channel has a further outlet opening which is in fluidically communicating connection with a profile recess formed in the profile extension, which in turn is at least partially covered by the toothed belt in order to be able to provide either positive pressure or negative pressure for the profile recess.

[0012] In an advantageous embodiment of the invention, the guide arrangement is provided that it is penetrated by a guide channel extending along the axis of movement, which is designed for the linearly movable reception of the cover strip, and that at least one fluid channel section of the at least one fluid channel runs in a wall section of the guide arrangement extending between the guide channel and the guide recess. The guide channel, which extends along the axis of movement through the guide arrangement, allows the cover strip intended for covering the guide recess to be partially lifted from the profile extension in order to enable the engagement of the at least one guide element in the guide recess.As an example, it is provided that sliding guides for the cover strip are arranged at each end of the guide channel. These guides enable an S-shaped deflection of the cover strip, thereby ensuring that, during the desired linear relative movement of the profile boom and the cover strip attached to it, the cover strip lifts and lowers locally from the profile boom in the area of ​​the guide recess, or is lowered onto the profile boom in the area of ​​the guide recess. The arrangement of the fluid channel, at least partially, in the wall section of the guide assembly extending between the guide channel and the guide recess allows the outlet opening to be positioned directly opposite the guide recess.

[0013] Preferably, the guide arrangement comprises at least one braking device designed to provide braking forces between the guide arrangement and the profile arm, and which is sealed to at least one opening. The function of the braking device, which serves particularly as a locking device, can be, in particular, to temporarily maintain a backlash-free relative position between the profile arm and the guide arrangement. This is important, for example, when a workpiece is to be positioned relative to a tool using the linear drive, and machining forces act on the linear drive during the machining of the workpiece.Such backlash-free positioning between the profile boom and the guide assembly is not usually achieved solely through the interaction between the toothed belt, the drive motor, and the associated gear, since the toothed belt has a certain elasticity, the toothed belt's engagement with the gear is not backlash-free, and backlash-free locking of the drive motor requires considerable technical effort. In contrast, the braking device is designed to selectively provide a frictional force between the guide assembly and the profile boom, thereby enabling the desired temporary, and in particular backlash-free, fixing of the profile boom to the guide assembly. Additionally or alternatively, the braking device can also be designed for a positive-locking connection between the profile boom and the guide assembly.For this purpose, the profile boom can, for example, be provided with a toothed section into which a rack associated with the braking device engages, in order to ensure a mechanically robust, positive-locking connection between the profile boom and the guide assembly. In any case, it is provided that the braking device is sealed and thus fluid-tight, connected to at least one outlet opening and is designed for fluidic actuation. By way of example, it can be provided that the braking device, depending on whether the fluid channel is subjected to overpressure or underpressure, provides or releases the frictional and / or positive-locking connection between the profile boom and the guide assembly.

[0014] It is advantageous if the braking device comprises a working chamber and at least one working piston movably mounted within the working chamber, wherein the working piston is associated with a braking surface, in particular a brake lining, and a spring element, wherein the braking surface, in particular the brake lining, is designed to provide a braking force when in contact with the profile boom, and wherein the spring element is designed to define a preferred position for the working piston. The braking device is designed in the manner of a fluid cylinder, wherein the working chamber is in fluidic communication with the at least one outlet opening and thus, depending on whether the fluid channel is pressurized or vacuumed, allows pressure to be applied to the working piston movably mounted within the working chamber.Preferably, the working piston is designed to provide a linear movement, wherein a brake pad associated with the working piston has no frictional connection with the profile arm in a first operating position of the working piston and is in frictional contact with the profile arm in a second operating position, thus producing the desired braking effect. The function of the spring is to apply a preload force to the working piston in order to establish a preferred position for the working piston and the associated brake pad when the working chamber is not supplied with fluid. The spring can be configured to preload the working piston into a preferred position that corresponds to either the first or the second operating position, depending on the design of the spring.

[0015] Alternatively, the braking device can have a working chamber that is partially bounded by an elastic membrane or designed as a hose section. This allows for elastic deformation of the membrane or hose section depending on the pressure applied to the working chamber, thus generating the desired braking force between the guide assembly and the profile boom.

[0016] In a further embodiment of the invention, the working chamber is fluidically connected to the outlet opening and to at least one throttle opening, the at least one throttle opening opening into the guide recess. This allows for a dual use of the pressurized fluid or vacuum provided at the connection opening. In a first function, the pressurized fluid or vacuum is used to actuate the braking device. Furthermore, in a second function, the pressurized fluid flows out of the throttle opening, or a vacuum is applied to the throttle opening, ensuring overpressure or underpressure of the guide recess.

[0017] Alternatively, in addition to the fluid channel extending between the connection opening and the outlet opening, at least one further, separately designed brake air channel is formed in the guide assembly, to which the brake device is connected and which is intended for connection to a brake air source. In this case, brake air can be supplied separately via the brake air channel, and overpressure or underpressure for the guide recess can be supplied via the fluid channel.

[0018] It is advantageous if the fluid flow resistance between the at least one throttle opening and the working chamber is chosen to be greater than the fluid flow resistance between the working chamber and the discharge opening. This measure ensures the desired dual function for the pressurized fluid or the vacuum with regard to the combined control of the braking device and the pressurization or vacuum application to the guide assembly. For example, the fluid flow resistance between the throttle opening and the working chamber, the fluid flow resistance between the working chamber and the discharge opening, and the braking device can be coordinated such that the braking device provides a braking effect between the profile boom and the guide assembly without the supply of pressurized fluid or vacuum, and when pressurized fluid or vacuum is supplied, the braking effect is activated.Negative pressure cancels the braking effect. This measure ensures that relative movement between the profile boom and the guide assembly is only permitted if the respective advantageous positive or negative pressure is also guaranteed in the guide assembly.

[0019] An advantageous embodiment of the invention is shown in the drawing. Here, the drawing shows: Fig. 1 a perspective overview of an automation component designed as a toothed belt boom, Fig. 2 a cutaway schematic front view of the automation component according to the figure, and Fig. 3. A partially cut-away side view of the automation component according to the Fig. 1 and Fig. 2 with an optional braking system.

[0020] One in the Fig. The automation component 1, schematically depicted and also referred to as a linear drive, is designed purely as an example of a toothed belt extension and serves to provide linear motion. For this purpose, the profile extension 2 is mounted for linear movement on a guide assembly 3. The guide assembly 3 comprises, under a cover designed as a housing part 4, a toothed belt guide (not shown) which is designed to introduce a linear motion onto the profile extension 2. For this purpose, a toothed belt 5 is fixed at each end of the profile extension 2. Within the guide assembly 3, in a volume covered by the housing part 4, the toothed belt partially encircles a gear (not shown) that can be fixed in a rotationally fixed manner on a drive shaft (also not shown) of a drive motor (not shown) that can be flanged to the guide assembly and set into a rotational motion.This results in a force being transmitted from the gear to the toothed belt 5, which in turn causes a linear displacement of the profile arm 2 relative to the guide arrangement 3. For illustrative purposes, the drive motor is designed as an electric motor and, with suitable control by a control device (not shown), can cause the gear to rotate in opposite directions.

[0021] As can be seen from the depiction of the Fig. As can be seen further in section 1, the housing part 4 is essentially U-shaped and has a first, in the Fig. 1 visible U-leg 6 and one aligned parallel to it, in the Fig. 1. A second, non-visible U-shaped leg extends between the two U-shaped legs, with an arcuate connecting section 7 extending between them. Both the U-shaped leg 6 and the non-visible U-shaped leg of the housing part 4 are positively locked by a locking device 10, which in turn is fixed to a support structure of the guide arrangement 3. The support structure of the guide arrangement 3 comprises, by way of example, a base plate 11 and a spaced-apart and parallel-oriented support plate 12, which are connected to each other by means of several connecting pins (not shown in detail).

[0022] The profile arm 2 is, by way of example, designed along a straight axis of movement 8 with a constant profile, preferably as an extruded profile, in particular as an aluminum extruded profile. Support bodies 20, 21 are arranged on oppositely oriented end faces 18, 19 of the profile arm 2. These support bodies are, by way of example, designed as plane-parallel plates with a rectangular outer contour and bear against the respective end face 18, 19 with their largest surface area 22, 23. Adjacent to the support bodies 20, 21, clamping devices 24, 25 are, in particular exclusively, slidably mounted in a profile recess 26 of the profile arm 2. These clamping devices are each designed to define a free end region 27 of the toothed belt 5.

[0023] As an example, it is provided that the profile recess 26 of the profile arm 2 is covered by the toothed belt 5 and the guide arrangement 3, with teeth 32 of the toothed belt 5 projecting into the profile recess 26. Since the path of the toothed belt 5 in the guide arrangement 3 roughly corresponds to the shape of the Greek letter Omega, this is also referred to as an Omega drive.

[0024] As the depiction of the Fig. The clamping device 24, which can still be removed, is kinematically coupled to the support body 20 via a tensioning device 28, which is shown here as a screw. The tensioning device 28 allows a tensioning force to be applied along the axis of movement 8 from the clamping device 24 to the toothed belt 5. The purpose of the clamping devices 24 and 25 is to ensure a tensile force transmission between the toothed belt 5 and the profile arm 2, thus enabling the toothed belt 5 to be tensioned so that it is always in a specific position relative to the gear.

[0025] On the profile extension 2, a guide recess 82 is formed on a side surface adjacent to the side surface provided with the profile recess 26. This guide recess extends along the axis of movement 8 with a constant, essentially U-shaped, profile and is particularly prominent in the Fig. 3 is shown in more detail. The guide recess 82 is covered along its entire length by a cover strip 83, which is shown purely as an example of a metal strip and in the Fig. Figure 1 is shown only in sections to provide insight into the guide recess 82. By way of example, it is provided that the cover strip 83 is received at each end in recesses 84 formed in the support bodies 20 and 21, wherein in the Fig. 1 only the recess 84 in the support body 21 is visible. Furthermore, each of the support bodies 20, 21 comprises fastening means assigned to the respective recess 84 (not shown in detail) with which the cover strip 83 can be fixed to the respective support body 20, 21 and, if necessary, tensioned. In addition, as shown in the illustration of the Fig. 3 a magnetic strip 124, 125 extending along the axis of movement 8 is attached to the edge of the guide recess 83, with which a sealing adhesion of the cover strip 83, which is made as a thin metal strip from a magnetizable metal material, can be effected to the profile extension 2.

[0026] To allow the guide elements 85, 86 to engage in the guide recess 82 covered by the cover strip 83, the cover strip 83 must be partially lifted from the guide recess 82. For this purpose, the base plate 11, by way of example, has a recess in the Fig. The guide shaft 87, shown in more detail in Figure 2, allows the guide elements 85, 86 to engage behind the cover band 83. By way of example, the guide shaft 87 is provided to extend completely through the base plate 11 along the axis of movement 8 and is equipped at each end with sliding guides 88, 89 designed for an S-shaped deflection of the cover band 83. By way of example, a spring device 90 is provided to each end of the sliding guide 88 arranged on the guide shaft 87. This spring device presses, for example, a first L-shaped leg 91 of the sliding guide 88 onto a surface 93 of the cover band 83, while a second L-shaped leg 92 of the sliding guide 88 is fixed to the base plate 11. This measure ensures that the surface 93 of the cover strip 83 is flush with a surface 94 of the profile extension 2, into which the guide recess 82 is inserted, away from the guide shaft 87.

[0027] At one in the Fig. On the outer surface 95 of the base plate 11, shown in Figure 1 as a purely exemplary illustration and facing away from the guide recess 82, a connection opening 96 is arranged, which is provided for the connection of a fluid hose (not shown in detail), in particular with an intermediate hose coupling (also not shown). The fluid hose can in turn be connected to a fluid source (also not shown), in particular a compressed air source, or a fluid sink, in particular a vacuum pump.

[0028] As can be seen from the depiction of the Fig. As can be seen from section 3, the base plate 11, between the connection opening 96 and a discharge opening 97, is penetrated by a fluid channel 98, which, by way of example, comprises three fluid channel sections 99, 100, 101, each designed as a cylindrical bore. Fluid channel section 99 is, by way of example, designed as a bore oriented perpendicular to the outer surface 95. Furthermore, fluid channel section 100 is, by way of example, designed as a bore oriented perpendicular to a lower surface 102 of the base plate 11 and provides a second connection opening 104 on the lower surface 102 of the base plate 11. Fluid channel section 101 is, by way of example, oriented perpendicular to an inner surface 103 of the base plate 11. Optionally, one of the two connection openings 96 or 104 is closed, while the other connection opening 96 or 104 can be connected to the compressed air source or the fluid sink in a manner not shown in detail.

[0029] The outlet opening 97 is formed at the end of the fluid channel section 101 and allows fluid to flow into or out of the guide recess 82. As shown in the illustration of the Fig. As can be seen from Figure 2, it is provided purely by way of example that the position of the mouth opening 97 along the axis of movement 8 is chosen such that it is arranged between the first guide element 85 and the second guide element 86 and thus enables an advantageous fluid flow between the two guide elements 85 and 86.

[0030] As can be seen from the depiction of the Fig. As can be seen from Figure 3, a separately formed guide rail 105 is arranged in the guide recess 82 (purely by way of example), which is fixed to the profile extension 2 by several fastening elements 106 distributed along the axis of movement 8. (Purely by way of example) four guide surfaces 107, 108, 109 and 110 are provided on the guide rail 105, each extending along the axis of movement 8 with a quarter-circle profile, which each serve for the support and rolling motion of a rolling element 111, exemplified as a ball. Each of the guide elements 85, 86 is assigned, purely by way of example, a plurality of rolling elements 111, which are guided within the guide elements 85, 86 in the manner of a recirculating ball bearing to ensure the lowest possible friction and most precise bearing of the guide rail 105 and the associated profile extension 2 relative to the guide arrangement 3.

[0031] During the Fig. The automation component 1 shown in section 3 differs from the automation component 1 according to the Fig.2. Additionally, a braking device 115 is provided, which is intended for the temporary provision of a frictional force between the guide arrangement 3 and the guide rail 105 of the profile boom 2. The braking device 115 is designed for fluidic actuation and, for this purpose, is fluidically connected to the opening 97 via a working channel 116. The working channel 116 opens into a working chamber 117, which is, for illustrative purposes, designed as a circular cylinder and in which a working piston 118 is linearly movable. Furthermore, two throttle openings 119, 120 are assigned to the working chamber 117, each opening into the guide recess 82. The cross-section of the working channel 116 is dimensioned such that the fluid flow resistance of the working channel 116 is less than the total fluid flow resistance of the two throttle openings 119, 120.This ensures that, due to the throttling effect of the two throttle openings 119, 120, there is always a pressure difference between the guide recess 82 and the outlet opening 97 as soon as the fluid channel 98 is subjected to overpressure or underpressure.

[0032] Furthermore, a spring element 121 is arranged in the working chamber 117. This spring element is designed, purely by way of example, as a compression spring and exerts a spring force on the working piston 118 in the direction of the guide rail 105. By way of example, the spring element 121 is designed with a spring force such that, when the fluid channel 98 is pressurized, a linear movement of the working piston 118 and the brake pad 122 (which is arranged thereon) occurs. This movement lifts the brake pad 122 from a surface 123 of the guide rail 105, thus eliminating any frictional force between the profile extension 2 and the guide arrangement 3. Conversely, when the pressurization of the fluid channel 98 is discontinued, the spring element 121 ensures a frictional engagement of the brake pad 122 with the surface 123 of the guide rail 105.This measure ensures that a relative movement of the profile boom 2 with respect to the guide arrangement 3 only takes place if, firstly, a force is applied from the drive motor to the toothed belt 5 and, secondly, sufficient negative pressure is applied to the fluid channel 98 to ensure reliable extraction of any particles that may be released between the guide elements 85, 86 and the guide rail 105.

[0033] In a variant of the braking device not shown, it is designed to release the linear movement between profile extension 2 and guide arrangement 3 in the event of overpressure in the guide recess 82.

Claims

[1] Linear drive for providing a linear motion, comprising a profile arm (2) extending along an axis of motion (8) and a guide arrangement (3) arranged linearly movable along the axis of motion (8) on the profile arm (2), the guide arrangement comprising a gear mounted for rotation, and a toothed belt (5) extending along the axis of motion (8), which partially wraps around the gear and is fixed at each end to the profile arm (2), wherein the profile arm (2) has a guide recess (82) extending along the axis of motion (8), in which at least one guide surface (107, 108, 109, 110) is formed for a linearly movable bearing of the guide arrangement (3), wherein the guide arrangement (3) comprises at least one guide element (85, 86) that engages in the guide recess (82) and rests on the guide surface (107, 108, 109, 110) is available,wherein at least one connection opening (96) is formed on an outer surface (95) of the guide arrangement (3) and wherein at least one outlet opening (97) is formed on an inner surface (103) of the guide arrangement (3) facing the guide recess (82), wherein the guide arrangement (3) is penetrated by at least one fluid channel (98) between the at least one connection opening (96) and the at least one outlet opening (97), characterized by , that a cover strip (83) is assigned to the profile extension (2), which extends with a longest edge parallel to the axis of movement (8) and which covers the guide recess (82). [2] Linear drive according to claim 1, characterized by, that the guide arrangement (3) has a first guide element (85) and a second guide element (86) which are spaced apart from each other along the axis of movement (8) and that at least one opening (97) is arranged between the two guide elements (85, 86). [3] Linear drive according to claim 1, characterized by , that the guide arrangement (3) is penetrated by a guide shaft (87) extending along the axis of movement (8) which is designed to receive the cover band (83) in a linearly movable manner and that at least one fluid channel section (99, 100, 101) of the at least one fluid channel (98) runs in a wall section of the guide arrangement (3) extending between the guide shaft (87) and the guide recess (82). [4] Linear drive according to any one of the preceding claims, characterized by, that the guide arrangement (3) comprises at least one braking device (115) designed to provide braking forces between the guide arrangement (3) and the profile extension (2) and which is sealed to at least one outlet opening (97). [5] Linear drive according to claim 4, characterized by , that the braking device (115) comprises a working chamber (117) and at least one working piston (118) movably received in the working chamber (117), wherein a braking surface and a spring means (121) are assigned to the working piston (118), wherein the braking surface is designed to provide a braking force when in contact with the profile extension (2) and wherein the spring means (121) is designed to specify a preferred position for the working piston (118). [6] Linear drive according to claim 5, characterized by, that the working space (117) is fluidically connected to the outlet opening (97) and to at least one throttle opening (119, 120), wherein the at least one throttle opening (119, 120) opens into the guide recess (82). [7] Linear drive according to claim 6, characterized by , that a fluid flow resistance between the at least one throttle opening (119, 120) and the working chamber (117) is chosen to be greater than a fluid flow resistance between the working chamber (117) and the outlet opening (97).

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