Linear drive device

Abstract

Linear drive device, comprising a spindle drive (6) which has a linearly displaceable, rotationally secured output unit (3) along a main axis (5) extending in a main axis direction (5a), a spindle nut (55) formed as a component of the output unit (3), and a threaded spindle (46) engaged in thread engagement with the spindle nut (55), wherein the threaded spindle (46) can be driven by an electric rotary drive device (74) to a rotary spindle movement (52) about its longitudinal axis (47) parallel to the main axis (5), wherein this rotary spindle movement (52) results in a first linear output movement (65) of the output unit (3) oriented in the main axis direction (5a) due to the thread engagement with the spindle nut (55), wherein the linear drive device (1) additionally comprises a fluid-actuated linear drive (7) in addition to the spindle drive (6).which has a linear drive unit (27) that can be driven by controlled fluid application to a linear drive movement (28) in the main axis direction (5a), wherein the linear drive unit (27) engages the threaded spindle (46) so that the threaded spindle (46) can be driven by the linear drive unit (27) to a linear spindle movement (67), from which a second linear output movement (66) oriented in the main axis direction (5a) of the output unit (3) coupled to the threaded spindle (46) via the spindle nut (55) results, wherein the threaded spindle (46) is displaceable between an axially retracted spindle end position and an axially extended spindle end position by the linear spindle movement (67) that can be generated by the fluid-actuated linear drive (7) to produce the second linear output movement (66) of the output unit (3), thereby characterizedthat the spindle drive (6) has a spindle drive housing (15) and the fluid-actuated linear drive (7) has a linear drive housing (16) combined with the spindle drive housing (15) to form a base unit (2), wherein the output unit (3) is linearly displaceable relative to the spindle drive housing (15) and rotationally secured with respect to the spindle drive housing (15), wherein the linear drive unit (27) can be driven relative to the linear drive housing (16) to the linear drive movement (28) and wherein the threaded spindle (46) can be driven relative to the base unit (2) to the linear spindle movement (67) and is displaceable relative to the base unit (2) to produce the second linear output movement (66) of the output unit (3), wherein the linear drive device (1) has a locking device (89),by which the threaded spindle (46) in the extended spindle end position can be locked axially immovably with respect to the base unit (2) while maintaining its rotatability relative to the base unit (2), which enables the rotary spindle movement (52).

Description

The invention relates to a linear drive device, having a spindle drive which has a drive output unit which is linearly displaceable along a main axis extending in a main axis direction and which is secured against rotation, a spindle nut which is formed as a component of the drive output unit and a threaded spindle which is in threaded engagement with the spindle nut, wherein the threaded spindle can be driven by means of an electric rotary drive device to produce a rotary spindle movement about its longitudinal axis parallel to the main axis, wherein a first linear drive output movement of the drive output unit which is oriented in the main axis direction results from this rotary spindle movement on account of the threaded engagement with the spindle nut, wherein the linear drive device has, in addition to the spindle drive, a fluid-actuated linear drive which has a drive output unit which can be driven in the main axis direction by controlled fluid application to a linear drive movement, wherein the linear drive unit acts on the threaded spindle, such that the threaded spindle can be driven by the linear drive unit to produce a linear spindle movement, from which a second linear output movement, oriented in the main axis direction, of the output unit coupled to the threaded spindle via the spindle nut results, wherein the threaded spindle, for producing the second linear output movement of the output unit, can be displaced between an axially retracted spindle end position and an axially extended spindle end position by the linear spindle movement that can be produced by the fluid-actuated linear drive.A linear drive device of this type known from DE 10 2013 007 604 A1 has a spindle drive which has a spindle nut to which a cardan ring is fastened. The spindle nut is seated on a ball screw spindle which can be driven in rotation by electric motor via a gear mechanism. Rotation of the ball screw causes a linear output movement of the spindle nut and of the cardan ring fastened thereto. Alternatively, the threaded spindle can be hydraulically displaced, wherein it carries the spindle nut seated thereon with it linearly together with the gimbal ring. The hydraulic oil required for this can be fed through a channel into a cylinder space bounded by the ball screw.DE 10 2019 202 898 A1 describes a drive system which is in particular designed as a robot and which has a fluid-actuated linear drive which has a drive unit which can be driven to perform a drive movement and on which an electrically and fluidically actuatable working unit is mounted. The linear drive is equipped with a control valve device which can be controlled by an internal electronic control device in order to cause the drive movement of the drive unit.From GB 733 840 A an actuator is known which comprises a spindle connected to a rod on which a nut is seated which is rotationally drivable in order to axially move the spindle and thus also the rod. A piston is fastened to the spindle, which piston can be acted upon by a fluid in order to displace the spindle and thus also the rod by means of fluid force, wherein the nut rotates freely.U.S. Pat. No. 3,080,852 A relates to a stroke drive which has a piston which is displaceable by fluid force. A retracted end position of the piston can be specified by means of a stop which is arranged on a threaded spindle which is screwed into the piston and which can be rotated by electric motor, so that it changes its axial position relative to the piston.WO 2010 / 129 960 A1 describes a linear drive which has a spindle drive and a pneumatic drive connected in parallel for safety reasons. An output part can thus be moved optionally electromechanically or pneumatically.DE 103 47 423 A1 discloses a tool drive unit for driving a thread former in a thread production device. The tool driver assembly comprises a spindle which is mounted axially displaceably in a driver housing and functions as a retaining element for a thread forming tool. Furthermore, the tool driving unit has a rotary drive device for the spindle and an axial feed and return device for the spindle.DE 60 2004 000 462 T2 describes an actuating drive which can be operated in a hydraulic mode and in a mechanical mode and thus has two possible operating modes.A linear drive device known from EP 0 936 026 A2 has a spindle drive with a tubular output unit which is in threaded engagement with a threaded spindle via a spindle nut, which can be driven to perform a rotational spindle movement by an electric rotary drive device attached to a spindle drive housing. Since the output unit is secured against rotation with respect to the spindle drive housing, the rotational spindle movement brings about a purely linear output movement of the output unit relative to the spindle drive housing. This output movement can be tapped for the movement and positioning of objects. The spindle drive allows positioning of the output unit with high precision, but is subject to certain restrictions with regard to the achievable travel speed.DE 10 2019 202 898 A1 discloses a drive system with a fluid-operated linear drive, with which high positioning speeds can be realized. For exact positioning, a relatively high control effort is required.The object of the invention is to provide a linear drive device which offers a high positioning accuracy during rapid movements.To achieve this object, in a linear drive device in conjunction with the features mentioned at the beginning, it is provided that the spindle drive has a spindle drive housing and the fluid-actuated linear drive has a linear drive housing combined with the spindle drive housing to form a base unit, wherein the output unit is linearly displaceable relative to the spindle drive housing and secured against rotation with respect to the spindle drive housing, wherein the linear drive unit is drivable relative to the linear drive housing to produce the linear drive movement and wherein the threaded spindle is drivable relative to the base unit to produce the second linear output movement of the output unit is displaceable relative to the base unit, wherein the linear drive device has a locking device by means of which the threaded spindle is releasably lockable axially in an axially non-displaceable manner in the extended spindle end position while maintaining its rotationability with respect to the base unit enabling the rotational spindle movement.In this way, a linear drive device is provided which has a hybrid drive technology consisting of an electrically drivable spindle drive and a fluid-actuated linear drive, wherein a common, linearly movable output unit is assigned to the two drives, which output unit can be moved at high speed as required and can be positioned axially with high accuracy. Overall, the output unit can be driven to a working stroke movement following an imaginary main axis, which is composed of a first linear output movement that can be produced by the spindle drive and a second linear output movement that can be produced by the fluid-actuated linear drive. The two linear output movements can be brought about by corresponding actuation of the spindle drive and of the fluid-actuated linear drive, in particular successively, but preferably also in a temporally superimposed manner. By means of the fluid-actuated linear drive, the output unit can be displaced at high speed and thus quasi with a fast motion, while the spindle drive is predestined for precise fine positioning of the output unit after a rough positioning carried out by means of the fluid-actuated linear drive. The first linear output movement of the output unit, which can be generated by means of the spindle drive, results from a rotational spindle movement of the threaded spindle, which can be generated by means of an electric rotational drive device and with which a spindle nut belonging to the output unit is in threaded engagement, wherein a rotation prevention of the output unit, which is realized with respect to the base unit, has the result that the spindle nut moves in the longitudinal direction of the threaded spindle when the threaded spindle rotates and thereby generates the first linear output movement. The second linear output movement of the output unit results from the fact that the entire threaded spindle, including the output unit seated thereon, is displaced by means of the fluid-actuated linear drive, wherein the linear drive has a linear drive unit which engages on the threaded spindle and is displaceable relative to the linear drive housing and therefore also relative to the base unit by controlled fluid loading. The linear drive is in particular a pneumatic linear drive, but a hydraulic functional principle is likewise possible. For the rotational spindle movement, an electric rotary drive device can be used, which is expediently embodied as an integral component of the linear drive device, so that the spindle drive represents an electric spindle drive. The two drive principles can be combined compactly with one another, so that the linear drive device can be produced with small dimensions and low weight.The threaded spindle is displaceable relative to the base unit during its linear spindle movement between an axially retracted spindle end position and an axially extended spindle end position. The linear spindle movement is caused by the linear drive movement of the linear drive unit of the linear drive synchronous therewith. An existing locking device is capable of releasably locking the threaded spindle in its extended spindle end position in a manner non-displaceable in the main axis direction with respect to the base unit. Even in the locked state, however, the threaded spindle retains its rotation capability, so that it can still execute the rotational spindle movement. The locking device can therefore only fix the relative axial position between the threaded spindle and the base unit in a positive-locking manner and does not affect the rotation capability of the threaded spindle independently of its operating state. By locking the extended spindle end position, the reaction forces occurring during a first linear output movement of the output unit subsequently caused by the spindle drive are introduced directly into the base unit via the locking device, so that they do not bear on the fluid-actuated linear drive loads. Theoretically, when the threaded spindle is locked, the linear drive can be switched to non-pressurized during the subsequent spindle operation, since it is not required to maintain the extended spindle end position.Advantageous further developments of the invention are evident from the dependent claims.The linear drive device expediently contains a control device which is in particular an electronic control device and by means of which the spindle drive for generating the rotational spindle movement and the linear drive for generating the linear spindle movement can be controlled independently of one another. The linear drive device is preferably equipped with a sensor system, by means of which linear and / or rotational movements of relevant components of the linear drive device can be detected in order to generate feedback signals for the electronic control device, with the aid of which a working stroke movement of the output unit can be controlled and in particular also regulated.To generate the rotational spindle movement of the threaded spindle, the linear drive device is expediently equipped with an electric rotary drive device arranged on the base unit. The electric rotary drive device preferably includes an electric motor, for example, a servomotor or a stepping motor. The rotary drive device can be coupled to the threaded spindle without a transmission, but it is recommended to provide an intermediate transmission and, in particular, a belt transmission. The use of a gear mechanism makes it possible in particular to place the rotary drive device transversely to the main axis next to the base unit and thus to realize a relatively short-circuiting linear drive device.It is advantageous if the linear drive has a linear drive unit which is linearly movable with respect to the linear drive housing and which has a drive piston which divides two drive chambers from one another in the linear drive housing, which drive chambers can be acted upon with a drive fluid in a controlled manner in order to generate the linear drive movement of the linear drive unit. A piston rod is attached to the drive piston, which piston rod establishes a mechanical connection to the threaded spindle, so that the linear drive movement of the linear drive unit directly results in the linear spindle movement. The linear drive is preferably realized as a pneumatic cylinder.In order to induce the rotational spindle movement, it can be provided that the electric rotary drive device acts directly on the threaded spindle, for example on a toothing attached to the threaded spindle. However, it is considered particularly expedient if the torque causing the rotational spindle movement is introduced into the threaded spindle via the linear drive unit. For this purpose, the linear drive unit is connected to the threaded spindle in a rotationally fixed manner and can in turn be driven in rotation by means of the electric rotary drive device. In this way, during the rotational spindle movement, a uniform rotation of the threaded spindle and of the linear drive unit takes place about one and the same axis of rotation extending in the main axis direction.Preferably, the linear drive unit is coupled via a spline toothing device, on the one hand, in a rotationally fixed manner and, on the other hand, in the main axis direction in an axially displaceable manner to an input shaft which is mounted rotatably with respect to the base unit and at the same time in an axially immovable manner. The torque provided by an electric rotary drive device is introduced into the input shaft by the input shaft being drivingly coupled to the electric rotary drive device. The spline toothing device ensures a transmission of torque between the input shaft and the linear drive unit coupled rotationally fixedly to the threaded spindle, wherein the spline toothing device simultaneously enables an axial relative displacement between the linear drive unit and the input shaft when the linear drive unit is actuated for the purpose of generating the second linear output movement of the output unit.The spline device preferably contains an external spline formed on the outer periphery of a spline shaft section of the linear drive unit, while the input shaft has a hollow shaft section into which the spline shaft section of the linear drive unit dips axially displaceably and on the inner periphery of which a complementary internal spline of the spline device is formed, which is in engagement with the external spline of the spline shaft section.The threaded spindle is preferably designed as a hollow spindle. As a result, the threaded spindle can externally engage around the linear drive housing at least along a part of its length, whereby particularly compact dimensions are possible. On the radial outer circumference of the hollow spindle there is a spindle thread which is in threaded engagement with a spindle nut thread of the spindle nut of the output unit enclosing the threaded spindle. During the rotational spindle movement, the threaded spindle performs a rotational movement relative to the section of the linear drive housing surrounded by it.Expediently, the threaded spindle, which is designed as a hollow spindle, has a drive wall which is axially mounted in front of the linear drive and to which the linear drive unit is fastened in a manner which permits axial force transmission and which preferably also permits rotational force transmission. Taking into account the drive wall, the threaded spindle is designed in particular in the shape of a cup.The output unit is preferably at least partially tubular and arranged such that it coaxially surrounds the threaded spindle at least in regions. During the first linear output movement, the axial overlap length between the output unit and the threaded spindle changes. In particular, the output unit assumes a position that is extended axially to a greater or lesser extent with respect to the threaded spindle.It is also considered favorable if the spindle drive housing is at least partially tubular and coaxially encloses at least one longitudinal section of both the output unit and the threaded spindle. In particular, there is an embodiment to the effect that the output unit can extend, during its linear output movements with variable length, out of the spindle drive housing enclosing it, which expediently also applies correspondingly to the threaded spindle.The linear drive device can be realized with a particularly short structural length if the linear drive housing, the threaded spindle, the output unit and the spindle drive housing are designed to overlap axially and in the process to enclose each other coaxially. Preferably, in a retracted end-of-stroke position of the output unit, the linear drive housing, the threaded spindle and the output unit are accommodated with full length within the spindle drive housing.In order to prevent rotation of the output unit with respect to the spindle drive housing formed as a component of the base unit, it is preferably provided that the output unit has on its radial outer periphery a plurality of anti-rotation ribs which are arranged distributed in the circumferential direction around the main axis and extend linearly in the main axis direction and which engage linearly slidingly displaceably in complementary anti-rotation grooves which are formed in a corresponding circumferential distribution on the inner periphery of a tubular longitudinal portion of the spindle drive housing enclosing the output unit. The output unit can be produced particularly cost-effectively if the anti-rotation ribs are formed only on the spindle nut. The realization of complex structures of the output unit is then concentrated on the spindle nut.The locking device is in particular designed such that the locking and unlocking of the threaded spindle carried out by it with respect to the base unit is dependent on the axial position which the output unit assumes during the first linear output movement, which can be generated by the spindle drive, relative to the threaded spindle. By virtue of the operating state of the locking device being predefined mechanically via the output unit, low-interference operation can be ensured without complicated electrical and / or fluidic control measures.During the first linear output movement generated by the spindle drive, the output unit is expediently displaceable relative to the threaded spindle between an output unit end position axially retracted with respect to the threaded spindle and an output unit end position axially extended with respect to the threaded spindle. The locking device is preferably designed such that the output unit effects the locking upon leaving the retracted output unit end position and upon arriving again in the retracted output unit end position, it brings about an unlocking.In an embodiment considered particularly expedient, the locking device has an annular locking groove formed on a radial outer periphery of the linear drive housing and furthermore has a multiplicity of locking elements which are arranged in an annular distribution around the linear drive housing. The locking elements are supported on the threaded spindle in an axially fixed manner in this respect, i.e. in the main axis direction, so that they also perform the linear spindle movement of the threaded spindle. Preferably, the locking elements are also immovably supported by the threaded spindle in the circumferential direction of the threaded spindle. In the radial direction of the threaded spindle, however, the locking elements are movable, so that they are movable between a radially further outward release position and a radially further inward locking position. The locking elements are placed in such a way that in the extended spindle end position they come to lie at the same axial height as the locking groove, while in the other possible axial spindle positions they are axially spaced apart from the locking groove. A release ring arranged axially displaceably on the threaded spindle is resiliently prestressed into an active position which presses the locking elements radially inward and is held by the output unit in an inactive position which allows the locking elements to escape radially from the locking groove, that is to say to be displaced into the release position, as long as the output unit is in the retracted output unit end position. When the output unit moves out of the retracted output unit end position, the release ring can be released for an axial movement relative to the threaded spindle in such a way that it can be displaced into its active position by the resilient prestress acting on it, in which it moves the locking elements into a locking position engaging into the locking groove and holds them there.For generating the resilient prestress, a mechanical spring device or a repulsive permanent magnet device, for example, is possible.The linear drive device can be operated in particular in such a way that the output unit is displaceable relative to the base unit within the scope of a working stroke movement between a retracted stroke end position and an extended stroke end position. The power stroke movement of the output unit can be composed of the first linear output movement and the second linear output movement. Starting from the retracted end-of-stroke position, the output unit expediently first executes the second linear output movement, which can be generated by the fluid-actuated linear drive and the end of which marks an intermediate-stroke position of the output unit. In this intermediate lifting position, the optional locking device is expediently activated. After reaching the intermediate stroke position, the working stroke movement continues within the scope of the first linear output movement until the extended end stroke position is reached. By appropriate actuation of the spindle drive, the extended stroke end position can be set very precisely.On the output unit or on an interface unit attached to the output unit, a fastening interface is expediently formed, on which an object to be moved and positioned can be attached, for example an end effector for carrying out handling work.The invention is explained in more detail below with reference to the attached drawings. In these show: FIG. 1 shows a preferred embodiment of the linear drive device according to the invention in a perspective view from a front side, FIG. 2 shows the linear drive device from FIG. 1 in a partially longitudinally cut-away perspective view, FIG. 3 shows a longitudinal section of the linear drive device according to section line II-II from FIG. 2, wherein the output unit is shown in a retracted stroke end position, FIG. 4 shows the linear drive device in a longitudinal section corresponding to FIG. 3 in an intermediate stroke position of the output unit, FIG. 5 shows the linear drive device in a longitudinal section corresponding to FIG. 3 in an extended stroke end position of the output unit, FIG. 6 shows a cross section of the linear drive device according to section line VI-VI in the region of the locking device, wherein the locking elements are shown in a non-locking release position, and FIG. 7 shows a cross section along the section line VII-VII from FIG. 5 in the region of the locking device, wherein the locking elements are shown when a locking position is assumed.The drawing shows a linear drive device 1 according to the invention, which has a base unit 2 and an output unit 3 which is linearly displaceable relative to the base unit 2. The displacement movement which can be carried out by the output unit 3 is referred to as the working stroke movement 4 and is identified by a double arrow. The working stroke movement 4 follows an imaginary main axis 5, indicated by a dot-dash line, of the linear drive device 1, the axial direction of which is referred to as the main axis direction 5 a.To produce the working stroke movement 4, the linear drive device 1 contains two drives of different types, namely an electrically actuatable spindle drive 6 and a fluid-actuated linear drive 7.By means of the moving output unit 3, any desired object 8 indicated only by dash-dot lines in FIG. 3 can be moved linearly and positioned along its movement path. The output unit 3 preferably has a fastening interface 12 suitable for the direct or indirect fastening of the object 8, which has, for example, an object bearing surface and a plurality of fastening holes. The object 8 is, for example, a gripper or another end effector or a movable component of a machine.The linear drive device 1 has a front side 13 and a rear side 14, wherein the main axis 5 extends between the front side 13 and the rear side 14. The linear drive device 1 can be operated with any desired spatial orientation of the main axis 5, for example with a horizontally or vertically oriented front side 13.The fastening interface 12 is expediently formed in the region of the front side 13 and in this case in particular on the end face of the output unit 3.The spindle drive 6 has a spindle drive housing 15 and the linear drive 7 has a linear drive housing 16. Both housings 15, 16 preferably have a longitudinal shape and extend in the main axis direction 5 a.The linear drive housing 16 has a housing tube 17 which extends in the main axis direction 5 aand is expediently connected to a rear housing flange 18 in the region of the rear side 14, in particular in a one-piece manner. The rear housing flange 18 has, in the region of the rear side 14, a rear mounting surface 22, on which a rotary drive unit 23 assigned to the spindle drive 6 is mounted.The linear drive housing 16 encloses an elongate housing interior 24, which is enclosed radially on the outside by the housing tube 17 and which is closed in the region of the front side 13 by a front end cover 25 and on the opposite rear side by a rear end cover 26. The rear end cover 26 is preferably cup-shaped and encloses an end cover interior which is open toward the rear side 14.A linear drive unit 27 extends in the linear drive housing 16, which can be driven in both axial directions by means of a drive fluid to a linear drive movement 28 indicated by a double arrow. It has a drive piston 31 accommodated in the housing interior 24, by means of which the housing interior 24 is divided into a front and rear drive chamber 32, 33 in a fluid-tight manner. A piston rod 34 of the linear drive unit 27 connected to the drive piston 31 and extending in the main axis direction 5 apasses through it in a sealed manner and passes in a slidingly displaceable manner through the front end cover 25 with a front piston rod section 34 aand the rear end cover 26 with a rear piston rod section 34 b.One of two fluid channels 35 a, 35 bopen into each drive chamber 32, 33, which extend in particular in the wall of the housing tube 17 and which each lead to a fluid line connection device 36 arranged from the outside on the base unit 2.In the operational state of the linear drive device 1, the two fluid channels 35 a, 35 bare connected via the fluid line connection devices 36 to fluid control lines 37, which are connected to a control valve device 38 that communicates with an electronic control device 42 for its actuation. In this way, a controlled fluid application of a drive fluid to the two drive chambers 32, 33 is made possible in order to cause the linear drive movement 28 of the linear drive unit 27. The drive fluid available from a pressure source P is in particular compressed air.The spindle drive housing 15 is at least partially tubular and has, for example, a housing tube 43, referred to below as outer housing tube 43, which encloses the housing tube 17 of the linear drive housing 16 coaxially, so that an annular space, referred to below as housing annular space 44, is located between the two housing tubes 43, 17. The outer housing tube 43 is expediently fastened on the rear housing flange 18 on the rear side and has a front tube opening 45 in the region of the front side 13; preferably, the housing tube 17 of the linear drive housing 16 is axially protruding a certain distance beyond the outer housing tube 43 on the front side 13.The spindle drive 6 further has a threaded spindle 46 having a longitudinal extent, the longitudinal axis 47 of which runs parallel to the main axis 5 and in particular coincides with this main axis 5. The threaded spindle 46 is preferably designed as a hollow spindle, which is realized in the illustrated exemplary embodiments, wherein it has a hollow cylindrical spindle section 48, with which it is seated in a coaxial arrangement on the housing tube 17 of the linear drive housing 16. The threaded spindle 46 is rotatable about its longitudinal axis 47 as an axis of rotation relative to the housing tube 17 of the linear drive 7, wherein the rotational movement resulting therefrom is referred to below as rotational spindle movement 52 and is illustrated by a double arrow. Means 53 arranged coaxially between the hollow cylindrical spindle section 48 and the housing tube 17, which are designed, for example, as sliding sleeves, enable a low-friction rotation of the threaded spindle 46 with at the same time precise radial support.The threaded spindle 46 is provided radially with an external thread, referred to below as spindle thread 54. The spindle thread 54 is situated, for example, on the radial outer periphery of the hollow cylindrical spindle section 48.The spindle drive 6 further has a spindle nut 55 which is seated coaxially on the threaded spindle 46 and has a spindle nut thread 56 on its radial inner periphery, which spindle nut thread is in threaded engagement with the spindle thread 54. The spindle nut 55 is an integral component of the output unit 3, so that the output unit 3 and the spindle nut 55 can always only be moved in a uniform manner.The output unit 3 is preferably at least partially tubular, wherein it has, for example, a tube section 57 coaxially surrounding the threaded spindle 46, on the end section of which, facing the rear side 14, the spindle nut 55 is fixedly attached.The output unit 3 coupled to the threaded spindle 46 via the spindle nut 55 is expediently radially supported with respect to the threaded spindle 46 in an axially displaceable manner by linear guide means 58. The linear guide means 58 are, for example, fixedly attached on the outside to the front end region of the hollow cylindrical spindle section 48, wherein the output unit 3 rests with the inner circumferential surface of the tube section 57 on the linear guide means 58 in a slidingly displaceable manner. The linear guide means 58 is, for example, a sliding guide sleeve.The output unit 3 has a longitudinal axis 62, which expediently coincides with the longitudinal axis 47 of the threaded spindle 46 designed as a hollow spindle.The output unit 3 has the output movement 4 as the only degree of freedom of movement. In particular, the output unit 3 is secured against rotation with respect to the base unit 2 and thus also with respect to the spindle drive housing 15, that is to say fixed in a non-rotatable manner, such that it cannot execute a rotational movement about the longitudinal axis 62.The anti-rotation device of the output unit 3 is preferably and, according to the illustrated exemplary embodiment, realized in that a plurality of anti-rotation ribs 63 which extend linearly in the main axis direction 5 aare formed on the radial outer periphery of the output unit 3, each of which ribs engages in one of a plurality of complementarily configured anti-rotation grooves 64 which are formed on the inner periphery of the outer housing tube 43 which represents a tubular longitudinal section of the spindle drive housing 15. The anti-rotation ribs 63 and the anti-rotation grooves 64 are distributed in a circumferential direction 61 indicated by a double arrow around the main axis 5, with which the longitudinal axes 47, 62 of the threaded spindle 46 and of the output unit 3 coincide, for example.The engagement of the anti-rotation ribs 63 in the anti-rotation grooves 64 prevents, on the one hand, rotation of the output unit 3 with respect to the base unit 2 about its longitudinal axis 62, but on the other hand allows a pure linear movement of the output unit 3 in the axial direction of the longitudinal axis 62 for carrying out the working stroke movement 4. the anti-rotation ribs 63 are expediently shorter than the anti-rotation grooves 64. By way of example, the anti-rotation grooves 64 extend over the entire axial length of the inner circumference of the outer housing tube 43. the shorter anti-rotation ribs 63 in this respect are arranged in particular on the rear end section of the output unit 3 facing the rear side 14, wherein they are expediently formed exclusively on the spindle nut 55 attached there. The spindle nut 55 thus has the rotation-preventing ribs 63 on the radial outer circumference and the spindle nut thread 56 on the radial inner circumference.Overall, the spindle drive housing 15, the output unit 3, the threaded spindle 46 designed as a hollow spindle and the linear drive housing 16 are arranged in an axially overlapping arrangement and coaxially surrounding one another, as can be seen clearly from FIG. 3.The working stroke movement 4 of the output unit 3 can be composed of a first linear output movement 65 that can be brought about by the spindle drive 6 and a second linear output movement 66 that can be brought about by the linear drive 7. The working stroke movement 4 can also consist, with corresponding actuation, of only the first linear output movement 65 or only the second linear output movement 66.The first linear output movement 65 results from the rotational spindle movement 52, as a result of which the output unit 3 is axially displaced in the main axis direction 5 arelative to the threaded spindle 46. The second linear output movement 66 results from the linear drive movement 28 of the linear drive unit 27, by means of which the threaded spindle 46 is driven relative to the base unit 2 to form a linear spindle movement 67 oriented in the main axis direction 5 a, wherein the output unit 3 fixed to the threaded spindle 46 via the spindle nut 55 and the threaded engagement thereof moves axially with the threaded spindle 46 synchronously. The linear spindle movement 67 and the rotational spindle movement 52 can be carried out successively or simultaneously in time, so that the two linear output movements 65, 66 can take place successively or simultaneously. Depending on this, the momentary power stroke movement 4 is composed of only the first linear output movement 65, or only the second linear input movement 66, or of overlapping first and second linear output movements 65, 66.While the output unit 3 displaces during the first linear output movement 65 both relative to the base unit 2 and relative to the threaded spindle 46, during the second linear output movement 66 it displaces only relative to the base unit 2, while it remains axially stationary with respect to the threaded spindle 46.The electronic control device 42 is in particular designed such that the spindle drive 6 and the linear drive 7 can be controlled independently of one another for generating the rotational spindle movement 52 and the linear spindle movement 67.The rotary drive unit 23 already mentioned is responsible for generating the rotary spindle movement 52. It is drivingly connected to a torque introduction section 68, which is coupled to the threaded spindle 46 in a rotationally fixed manner. The torque introduction section 68 is preferably attached to the linear drive unit 27 in a torque-transmitting manner, which in turn is connected to the threaded spindle 46 in a rotationally fixed manner, so that the rotational driving of the threaded spindle 46 takes place via the linear drive unit 27. In comparison with a likewise possible construction, in which the torque introduction section 68 is attached directly to the threaded spindle 46, particularly compact dimensions can be realized in this way.For example, the piston rod 34 is fastened to the threaded spindle 46 by the front end section 72 of the front piston rod section 34 aprotruding from the linear drive housing 16 in the region of the front end cover 25. The threaded spindle 46 expediently has a wall which is axially upstream of the linear drive housing 16 and which, for better differentiation, is referred to as a drive wall 73, to which the front end section 72 is attached. The drive wall 73 adjoins the hollow cylindrical spindle section 48 at the front in a particularly one-piece manner.The fastening of the piston rod 34 and thus of the linear drive unit 27 to the drive wall 73 is designed in such a way that both axial thrust and pressure forces can be transmitted and a torque in both directions of the circumferential direction of the longitudinal axis 47. For the transmission of torque, a plurality of axial extensions can be formed on the front side at the front end section 72 of the piston rod 34, which extend positively into complementary depressions of the drive wall 73.By way of example, the linear drive unit 27 which is connected to the threaded spindle 46 in a rotationally fixed manner can be driven in rotation by means of an electric rotary drive device 74 in order to generate the rotational spindle movement 52. The electric rotary drive device 74 directly or indirectly engages in terms of drive on the torque introduction section 68 which is connected to the linear drive unit 27 in a rotationally fixed manner and can introduce an input rotary movement 75 therein in the clockwise direction or in the counter-clockwise direction as desired according to the double arrow.The electric rotary drive device 74 is in particular an electric motor 74 a, for example a stepper motor or a servomotor.The electric rotary drive device 74 is preferably a component of the rotary drive unit 23 mentioned further above, which for example also has a transmission 76 interposed between the rotary drive device 74 and the torque introduction section 68. By way of example, the transmission 76 is a belt transmission with a drive belt 77, which is wound around an input wheel 78 a, which is attached to the rotary drive device 74, and an output wheel 78 b, which is attached to the torque introduction section 68 in a rotationally fixed manner. The drive belt 77 is preferably a toothed belt, wherein the two wheels 78 a, 78 bare toothed wheels. The gear 76 has a gear housing 79 which is mounted on the mounting surface 22 on the base unit 2 and on which the electric rotary drive device 74 is mounted in turn. Preferably, the electric rotary drive device 74 extends alongside the base unit 2, so that the linear drive device 1 can be realized with a short overall length.In an unillustrated embodiment, the rotary drive unit 23 is gearless and includes only the electric rotary drive device 74 directly flange-connected to the torque introduction portion 68.In order to enable the linear drive movement 28 of the linear drive unit 27, regardless of its use for the torque transmission, the linear drive unit 27 is expediently connected to the torque introduction section 68 via a spline device 82. The spline device 82 includes an external spline 83 on the outer periphery of a spline shaft portion 84 of the linear drive unit 27 and an internal spline 85 complementary to the external spline 83 on the inner periphery of a hollow shaft portion 86 of an input shaft 87 having the torque introduction portion 68.The input shaft 87 extends in a shaft receiving space 88 of the linear drive housing 16 adjoining the rear end cover 26 on the rear side, wherein it is aligned coaxially with the linear drive unit 27 and wherein the linear drive unit 27 dips axially with the spline shaft section 84 into the hollow shaft section 86. The input shaft 87 is rotatable about its longitudinal axis parallel to the main axis 5 relative to the base unit 2, but at the same time supported so as to be axially immovable.To generate the rotational spindle movement 52, the rotary drive device 74 generates an input rotary movement 75 on the input shaft 87, which owing to the toothed engagement of the splined toothed device 82 results in a rotation of the linear drive unit 27 and thus the rotational spindle movement 52.The transmission of torque through the splined toothed device 82 is ensured independently of the linear drive movement 28 and the instantaneous axial position of the linear drive unit 27, because the splined shaft section 84 is axially displaceable relative to the hollow shaft section 86 during the linear drive movement 28 while maintaining the toothed engagement.A preferred mode of operation of the linear drive device 1 begins in the basic state shown in FIG. 3, in which the output unit 3 assumes a stroke end position retracted into the base unit 2. This is associated with an axially retracted output unit end position assumed with respect to the threaded spindle 46 and a spindle end position axially retracted with respect to the base unit 2.In a first operating phase, the linear drive 7 is then actuated, so that the linear drive unit 27 moves out of the linear drive housing 16 in the region of the front side 13 while performing its linear drive movement 28, wherein it drives the threaded spindle 46 with it, so that the same performs a linear spindle movement 67. Since the threaded spindle 46 is not rotationally driven during this first operating phase illustrated in FIG. 4, the output unit 3 maintains its axially retracted output unit end position assumed with respect to the threaded spindle 46 and moves together with the threaded spindle 46 only while performing the second linear output movement 66, Overall, the output unit 3 thus performs a working stroke movement 4 in the first operating phase, which consists of the second linear output movement 66. The working stroke movement 4 and the second linear output movement 66, 66 end when the linear drive unit 27 has reached the extended stroke end position which can be seen from FIG. 4 and is defined, for example, by the linear drive unit 27 coming to bear with the drive piston 31 against the front end cover 25. The retracted end stroke position of the linear drive unit 27 is defined, for example, by the contact of the drive piston 31 with the rear end cover 26.When the linear drive unit 27 assumes the extended end-of-stroke position according to FIG. 4, the threaded spindle 46 has moved from the axially retracted spindle end position present in the basic state according to FIG. 3 relative to the base unit 2 in the direction of the front side 13 into an extended spindle end position. At the end of the first operating phase, the output unit 3 is in an intermediate stroke position, which can be seen from FIG. 4, with respect to the base unit 2.The first operating phase according to FIG. 4 is followed by a second operating phase, which is concluded in the configuration shown in FIG. 5. The second operating phase takes place while the threaded spindle 46 retains its extended spindle end position already present at the end of the first operating phase.During the second operating phase, the threaded spindle 46 is driven by the electric rotary drive device 74 via the co-rotating linear drive unit 27 to the rotary spindle movement 52. This has the result that the spindle nut 55, which is in threaded engagement with the threaded spindle 46 and is secured against rotation with respect to the base unit 2, is displaced axially in the direction of the front side 13 along the rotating threaded spindle 46 while performing a screwing operation. Since the spindle nut 55 is a component of the output unit 3, the entire output unit 3 executes the aforementioned linear movement, which is the first linear output movement 65 explained further above. The output unit 3 moves from the axially retracted output unit end position according to FIG. 4 assumed with respect to the threaded spindle 46 into an output unit end position according to FIG. 5 axially extended with respect to the threaded spindle 46. with respect to the base unit 2, this means that the output unit 3 moves within the scope of its continuing working stroke movement 4 from the intermediate stroke position according to FIG. 4 into the extended stroke end position visible in FIG. 5.The described operating mode makes it possible to displace the fastening interface 12 or an object 8 fixed thereto at high speed from the retracted stroke end position into the intermediate stroke position by means of the fluid-actuated linear drive 7 and then to move it with high precision from the intermediate stroke position into the extended stroke end position by means of the electric spindle drive 6.The extended stroke end position of the output unit 3 assumed with respect to the base unit 2 is variably adjustable in that the output unit 3 is axially displaced more or less far relative to the threaded spindle 46 by the first linear output movement 65. This can be influenced very easily via the number of spindle rotations caused.Of course, the second operating phase can also take place before the first operating phase or both operating phases can be carried out in a temporally superimposed manner.The return movement of the output unit 3 from the extended stroke end position into the retracted stroke end position takes place analogously to the extension, but with the reverse movement direction in the case of the rotational and linear spindle movement 52, 67.In a particularly preferred embodiment of the linear drive device, which can be seen from the drawing, the linear drive device 1 furthermore contains a locking device 89, by means of which the threaded spindle 46 can be locked in a releasable manner in an axially non-displaceable manner with respect to the base unit 2 in the extended spindle end position, which can be seen from FIGS. 4 and 5. Despite this locking, the rotation capability of the threaded spindle 46 for the required execution of the rotational spindle movement 52 is maintained. In this way, it is possible to positively block the axial relative position between the threaded spindle 46 and the base unit 2 present in the extended spindle end position independently of the pressurization of the linear drive unit 27. Axial reaction forces acting on the threaded spindle 46 of the output unit 3 are thus introduced directly into the base unit 2, bypassing the linear drive unit 27. The linear drive 7 is thereby relieved, which facilitates its service life.The locking device 89 can be designed such that it can be controlled with respect to its operating state by means of the electronic control device 42. However, a structure is preferred in which, according to the illustrated exemplary embodiment, the locking and unlocking of the threaded spindle with respect to the base unit 2 takes place purely mechanically depending on the axial position of the output unit 3 that the output unit 3 assumes during the first linear output movement, caused by the spindle drive 6, relative to the threaded spindle 46. In particular, a locking is effected when the output unit 3 moves out of the retracted output unit end position by the second linear output movement 66, wherein a renewed unlocking takes place when the output unit 3 returns again into the retracted output unit end position with the reverse direction of movement within the scope of a second linear output movement 66.A locking device 89 having the functionality described above is implemented in the illustrated exemplary embodiment in a particularly advantageous form, which is explained in more detail below.The locking device 89 has a locking unit 92 arranged on the threaded spindle 46 designed as a hollow spindle. This locking unit 92 carries along both the rotational spindle movement 52 and the linear spindle movement 66. It is preferably located on a tubular rear axial end section of the threaded spindle 46 facing the rear side 14, which is also referred to below as a locking section 93 of the threaded spindle 46 for better differentiation. The spindle thread 54 preferably ends axially in front of the locking section 93, so that the locking section 93 is designed without external threads.The wall of the threaded spindle 46 is radially traversed in the region of the locking portion 93 by a plurality of wall apertures 94 which are distributed in the circumferential direction 61 around the longitudinal axis 47 of the threaded spindle 46. Preferably, there is a uniform circumferential distribution of the wall apertures 94. All wall apertures 94 lie in a common plane, referred to as locking plane 95, which extends at right angles to the longitudinal axis 47.A locking element 96 preferably formed in the shape of a sphere is arranged in each wall aperture 94, so that the locking unit 92 has a plurality of locking elements 96, which are arranged distributed annularly around the linear drive housing 16, more precisely around its housing tube 17.The locking elements 96 and the wall apertures 94 are matched to one another such that the locking elements 96 can execute individual working movements 97 relative to the locking section 93 in the radial direction with respect to the longitudinal axis 47, but are otherwise supported by the locking section 93. The locking elements 96 can therefore move relative to the threaded spindle 46 in particular neither in the main axis direction 5 aor in the circumferential direction 61.The wall apertures 94 are contoured so that the locking elements 96 cannot escape or fall radially outward from the wall apertures 94. For this purpose, the wall apertures 94 expediently have a cross section which decreases radially outwards.The locking device 89 includes an annular locking groove 98 formed on the radial outer periphery of the linear drive housing 16. The locking groove 98, which is open radially outwards, is located in the housing tube 17 in an axial position which the locking elements 96 also assume when the threaded spindle 46 is in its spindle end position which can be seen from FIGS. 4 and 5.In all other axial positions of the threaded spindle 46, the locking elements 96 are located in a rear longitudinal section 99 of the housing tube 17 extending between the locking groove 98 and the rear housing flange 18.The locking unit 92 has a release ring 102 which is arranged axially displaceably and coaxially on the locking section 93 of the threaded spindle 46. The release ring 102 is located on the side of the locking elements 96 axially facing away from the spindle thread 54.The ring cross section framed by the release ring 102 widens towards a front end face 103 of the release ring 102 facing the output unit 3. This is in particular a conically widening inner circumferential section which is bounded by a radially inwardly pointing conical actuating surface 104.The release ring 102 is arranged on the locking section 93 so as to be axially displaceable. In this case, it is movable within the scope of an actuating movement 105 oriented in the same way as the main axis direction 5 aand indicated by a double arrow between an inactive position visible in FIGS. 3 and 4 and an active position visible in FIG. 5.The release ring 102 can only assume the active position according to FIG. 5 when the threaded spindle 46 assumes the extended spindle end position, so that the locking elements 96 are at the same axial height as the locking groove 98. In the active position, the release ring 102 assumes a position moved with the actuating surface 104 in front over the locking elements 96, in which the locking elements 96 are acted upon by the inner circumferential surface of the release ring 102 and are pressed into the locking groove 98, performing the working movement 97. The release ring 102 thereby prevents a radial escape of the locking elements 96 from the locking groove 98 Thus, the threaded spindle 46 is locked in a form-fitting manner in the extended spindle end position with respect to the housing tube 17 and thus the base unit 2 in the main axis direction 5 ain such a way that it cannot move.In the inactive position, the release ring 102 is moved away axially from the locking elements 96 at least so far toward the rear side 14 that the locking elements 96, while performing the working movement 97, can move radially outwards at least so far that they no longer engage in the locking groove 98. In other words, the locking elements 96 are allowed to escape radially from the locking groove 98 in the inactive position of the release ring 102.The release ring 102 is resiliently biased to the active position. For this purpose, the locking unit 92 contains, for example, a mechanical spring device 106 which continuously applies an axial pressing force to the release ring 102. The spring device 106 is seated, for example, axially between the release ring 102 and a support ring 107, which is likewise arranged on the locking section 93 but is fixed in an axially immovable manner in this respect. The support ring 107 is seated on the side of the release ring 102 axially opposite the output unit 3. The spring device 106 is, for example, a helical compression spring arranged coaxially with respect to the longitudinal axis 47.Instead of a spring device 106, a repulsively effective permanent magnet arrangement can also be provided, for example, which continuously presses the release ring 102 in the direction of the inactive position and which is preferably arranged partly in the release ring 102 and partly in the support ring 107.The output unit 3 has, on its axial end region facing the locking unit 92, a preferably annularly designed actuating portion 108. The actuating section 108 is expediently arranged coaxially with the release ring 102. The actuating section 108 is preferably an integral extension of the spindle nut 55.The actuating section 108 is designed such that, in the axially retracted output unit end position, it presses on the release ring 102 such that the latter is held in its inactive position. As long as this is the case, the threaded spindle 46 can execute the linear spindle movement 67 without hindrance, which is accompanied by the second linear output movement 66 of the output unit 3.However, when the output unit 3 moves out of the retracted spindle end position and in the direction of the extended spindle end position due to the rotational spindle movement 52, the actuating section 108 moves away from the trigger ring 102 so that the latter can move into the active position in which it locks the threaded spindle 46 axially immovably with respect to the base unit 2.Since the locking groove 98 is an annular groove, the threaded spindle 46 can also execute the rotational spindle movement 52 in the state locked by the locking device 89, wherein the locking elements 96 then circulate in the locking groove 98 around the housing tube 17.When the output unit 3 is moved by means of the linear drive 7 into the intermediate stroke position shown in FIG. 4, the release ring 102 still assumes the inactive position, so that the locking elements 96 can execute their radial working movement 97 unimpeded and can thereby be positioned as desired. The locking mechanism is then not yet active, so that upon a subsequent inward actuation of the linear drive unit 27, the output unit 3 can be displaced unimpeded into its retracted end-of-stroke position.However, when the output unit 3 is moved from the intermediate stroke position in the direction of the extended end stroke position by rotational actuation of the threaded spindle 46, the actuating section 108 releases the release ring 102 so that the latter can pass over the locking elements 96 and press them into the locking groove 98.Expediently, the threaded spindle 46 is provided in the region of its outer circumference with an axial distance from the locking elements 96 with an annular stop portion 109 which acts as a stroke limitation for the actuating movement 105 and stops the release ring 102 when the latter has reached the active position. The stop section 109 is preferably a stop ring which is separate with respect to the threaded spindle 46.The stop section 109 can expediently also cooperate with the output unit 3 in order to stop the same when it returns from the extended output unit end position into the retracted output unit end position.The inclined actuating surface 104 promotes the release ring 102 to be moved away via the locking elements 96. The stop portion 109 is expediently placed such that the locking elements 96 in the active position of the release ring 102 are superimposed radially outwards by a cylindrical portion of the inner circumferential surface 101 of the release ring 102.During the entire working stroke movement of the output unit 3, the locking unit 92 is located and moves within the housing annular space 44.At least in the inactive position of the release ring 102, the spring device 106 is compressed such that it exerts a resilient actuating force on the release ring 102 in the direction of the active position. Therefore, the release ring 102 is displaced by the spring device 106 into the active position as soon as it is released by the actuating section 108 of the output unit 3 for carrying out the actuating movement 105. The inclined actuating surface 104 promotes the release ring 102 to be moved away via the locking elements 96. The stop portion 109 is expediently placed such that the locking elements 96 in the active position of the release ring 102 are superimposed radially outwards by a cylindrical portion of the inner circumferential surface 101 of the release ring 102.

Claims

Linear drive device, having a spindle drive (6) which has a drive output unit (3) which is linearly displaceable along a main axis (5) extending in a main axis direction (5a), is secured against rotation, a spindle nut (55) which is formed as a component of the drive output unit (3) and a threaded spindle (46) which is in threaded engagement with the spindle nut (55), wherein the threaded spindle (46) can be driven by means of an electric rotary drive device (74) to form a rotary spindle movement (52) about its longitudinal axis (47) parallel to the main axis (5), wherein a first linear drive output movement (65) of the drive output unit (3) which is oriented in the main axis direction (5a) results from this rotary spindle movement (52) on account of the threaded engagement with the spindle nut (55), wherein the linear drive device (1) has, in addition to the spindle drive (6), a fluid-actuated linear drive (7), a linear drive unit (27) drivable by controlled fluid application to a linear drive movement (28) in the main axis direction (5a), wherein the linear drive unit (27) acts on the threaded spindle (46), so that the threaded spindle (46) can be driven by the linear drive unit (27) to a linear spindle movement (67), from which a second linear driven movement (66), oriented in the main axis direction (5a), of the driven unit (3) coupled to the threaded spindle (46) via the spindle nut (55) results, wherein the threaded spindle (46) can be displaced between an axially retracted spindle end position and an axially extended spindle end position by the linear spindle movement (67) which can be generated by the fluid-actuated linear drive (7) for inducing the second linear driven movement (66) of the driven unit (3), characterized in that, the spindle drive (6) having a spindle drive housing (15) and the fluid-operated linear drive (7) having a linear drive housing (16) combined with the spindle drive housing (15) to form a base unit (2), wherein the output unit (3) is linearly displaceable relative to the spindle drive housing (15) and secured against rotation with respect to the spindle drive housing (15), wherein the linear drive unit (27) is drivable relative to the linear drive housing (16) to produce the linear drive movement (28), and wherein the threaded spindle (46) is drivable relative to the base unit (2) to produce the linear spindle movement (67) and is displaceable relative to the base unit (2) to produce the second linear output movement (66) of the output unit (3), wherein the linear drive device (1) has a locking device (89), by means of which the threaded spindle (46) can be locked in an axially non-displaceable manner in the extended spindle end position while maintaining its rotation capability with respect to the base unit (2) enabling the rotational spindle movement (52).Linear drive device according to claim 1, characterised in that it has a control device (42), by means of which the spindle drive (6) and the linear drive (7) can be controlled independently of one another for generating the rotational spindle movement (52) and the linear spindle movement (67).Linear drive device according to claim 1 or 2, characterised in that it is equipped with an electric rotary drive device (74) arranged on the base unit (2) for generating the rotary spindle movement (52) of the threaded spindle (46), which rotary drive device expediently contains an electric motor (74a) coupled in terms of drive to the threaded spindle (46) via a gear mechanism (76).Linear drive device according to one of Claims 1 to 3, characterized in that the linear drive unit (27) of the linear drive (7) has a drive piston (31) which is arranged in the linear drive housing (16) and separates two drive chambers (32, 33), which can be acted upon by a drive fluid under controlled conditions in order to produce the linear drive movement (28), and a piston rod (34) which is connected to the drive piston (31) and is fastened to the threaded spindle (46).Linear drive device according to one of Claims 1 to 4, characterized in that the threaded spindle (46) is fastened to the linear drive unit (27) in a rotationally fixed manner, and the linear drive unit (27) is designed to be rotationally drivable by means of the electric rotational drive device (74) in order to generate the rotational spindle movement (52) of the threaded spindle (46).Linear drive device according to claim 5, characterised in that the linear drive unit (27) is coupled via a splined toothed device (82) in a rotationally fixed manner and axially displaceably in the main axis direction (5a) to an input shaft (87) mounted rotatably and at the same time axially immovably with respect to the base unit (2), wherein the input shaft (87) is coupled to the electric rotational drive device (74) in order to generate the rotational spindle movement (52) of the threaded spindle (46).Linear drive device according to Claim 6, characterized in that the spline toothing device (82) has an external spline toothing (83) which is formed on the outer periphery of a spline shaft section (84) of the linear drive unit (27), wherein the input shaft (87) has a hollow shaft section (86) into which the spline shaft section (84) of the linear drive unit (27) dips in an axially displaceable manner and on the inner periphery of which a complementary internal spline toothing (85) of the spline toothing device (82) which engages with the external spline toothing (83) of the spline shaft section (84) is formed.Linear drive device according to one of Claims 1 to 7, characterized in that the threaded spindle (46) is designed as a hollow spindle, wherein it has on its radial outer periphery a spindle thread (54) which is in engagement with a spindle nut thread (56) of the spindle nut (55) of the output unit (3) and coaxially encloses the linear drive housing (16) at least in regions in a manner which is rotatable and axially displaceable in this respect.Linear drive device according to claim 8, characterised in that the threaded spindle (46) has a drive wall (73) axially upstream of the linear drive housing (16), to which the linear drive unit (27) of the linear drive (7) is fastened in order to enable an axial and expediently also a rotational force transmission.Linear drive device according to one of Claims 1 to 9, characterized in that the output unit (3) is at least partially tubular and encloses the threaded spindle (46) coaxially at least in regions.Linear drive device according to one of Claims 1 to 10, characterized in that the spindle drive housing (15) is at least partially tubular and coaxially encloses at least one longitudinal section both of the output unit (3) and of the threaded spindle (46).Linear drive device according to claim 11 in conjunction with claims 8 and 10, characterised in that the spindle drive housing (15), the output unit (3), the threaded spindle (46) designed as a hollow spindle and the linear drive housing (16) are arranged so as to axially overlap and coaxially enclose one another.Linear drive device according to one of Claims 1 to 12, characterized in that, for preventing rotation with respect to the spindle drive housing (15), the output unit (3) has on its radial outer periphery a plurality of anti-rotation ribs (63) which are arranged distributed around the main axis (5) in the circumferential direction (61) and extend in the main axis direction (5a), engage in a linearly slidingly displaceable manner in complementary anti-rotation grooves (64) which are formed on the inner periphery of a tubular longitudinal section of the spindle drive housing (15) enclosing the output unit (3), wherein the anti-rotation ribs (63) are expediently formed only on the spindle nut (55).Linear drive device according to one of Claims 1 to 13, characterized in that the locking and unlocking of the threaded spindle (46) which takes place with respect to the base unit (2) can be brought about by the driven unit (3) as a function of the axial position of the driven unit (3) which can be taken in relative to the threaded spindle (46) when the first linear driven movement (65) can be generated by the spindle drive (6).Linear drive device according to one of Claims 1 to 14, characterized in that, during its first linear output movement (65) which can be generated by the spindle drive (6), the output unit (3) can be displaced between an output unit end position which is axially retracted with respect to the threaded spindle (46) and an output unit end position which is axially extended with respect to the threaded spindle (46), it being possible for the locking to be triggered by the output unit (3) leaving the retracted output unit end position and the unlocking to be triggered by the renewed arrival in the retracted output unit end position.Linear drive device according to claim 15, characterised in that the locking device (89) has an annular locking groove (98) formed on a radial outer periphery of the linear drive housing (16) and further contains a plurality of locking elements (96) arranged distributed annularly around the linear drive housing (16), which locking elements are supported axially immovable with respect to the threaded spindle (46) and are at the same time radially movable and which can move along the linear drive housing (16) together with the threaded spindle (46) during the linear spindle movement (67), wherein in the extended spindle end position they come to lie at the same axial height as the locking groove (98), wherein a release ring (102), which is axially displaceable in this respect and is resiliently prestressed into an active position which presses the locking elements (96) radially inwards, is arranged on the threaded spindle (46), wherein the release ring (102) is held by the output unit (3) in an inactive position allowing the locking elements (96) to escape radially from the locking groove (98) as long as the output unit (3) is in the retracted output unit end position and wherein the release ring (102) can be released for an axial movement when the output unit (3) moves out of the retracted output unit end position, so that it can be displaced into its active position by the resilient prestress.

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