EP0355179B1 - Linear actuator assembly - Google Patents

Description

The invention relates to a linear drive device, with a linear motor, in particular pneumatically operated by pressure medium, which has a housing in which there is an axially displaceable piston which is connected to an actuating rod protruding from the motor housing on one working side, in particular as a valve device trained control device for motor control, and with a responsive at certain positions of the actuating rod sensor device, wherein the control device and the sensor device are arranged in the region of the control side opposite the working side of the linear motor and are firmly connected to this to form a jointly manageable work unit.

In such linear drive devices, the linear motor is regularly designed as a piston-cylinder unit whose piston rod, which is connected to the piston and protrudes from the cylinder, represents the actuating rod which can be connected to a component to be moved or another power take-off. The linear motor is brought to the desired location and the pressure medium required for actuation, eg compressed air, is brought in or out via pressure medium lines or hoses. To control the pressure medium flow control devices are used, which are often designed as valve devices and are operated, for example, electrically. In order to bring about automatic motor control, a sensor device is provided which operates one or more, for example on an electrical, magnetic, pneumatic or mechanical basis May contain sensors with which predetermined positions of the actuating rod can be detected in order to switch the control device in dependence thereon.

A linear drive device of the type mentioned at the outset is known from DE-U-8632990. Your sensor device is formed by a position sensor which can be actuated in a contactless manner and which is mounted together with a solenoid valve forming the valve device in the region of the end face of the linear motor opposite the piston rod. The position sensor responds to the position of the piston and can actuate the solenoid valve to influence the operating state of the linear motor. Since the linear motor, the position sensor and the solenoid valve are combined to form a work unit that can be handled together, rapid assembly is possible at the respective place of use.

However, the known linear drive device has a relatively large width. This results mainly from the sensor device arranged on the outer circumference of the motor housing, which must be attached in the stroke area of the piston responsible for its actuation. In order to obtain a structural unit with the sensor device, the valve device is also provided radially outside the sensor device, as a result of which the overall width is increased again. Ultimately, it would also be problematic to implement a possibly desired adjustability of the sensor device, for which it would be necessary to keep a large part of the circumferential area of the linear motor free for the axial adjustment of the two devices.

It is therefore the object of the invention to create a linear drive device according to the type mentioned at the outset which, while maintaining the uniformly manageable working unit, has more compact transverse dimensions even if the sensor device may be desired to be adjustable.

This goal is achieved in that a switching rod is arranged on the piston side opposite the actuating rod, which is connected to the arrangement consisting of piston and actuating rod so as to be movable and has at least one rod portion on the control side protruding from the motor housing with the sensor device for actuating it cooperating switching section, and that the control device and the sensor device are arranged transversely to the axial direction next to each other in the axial direction following the linear motor on its control side, with a space of movement for the displacement movement of the shift rod being available between the two devices.

In this way, a very slim linear drive device is obtained, in which both the sensor device and the control device are arranged on the control side of the linear motor facing away from the piston rod, so that the peripheral area of the motor housing remains free and even in confined spaces, the drive device can be accommodated without problems is possible. At the same time, the two devices are practically shielded from the working side by the motor housing, which considerably reduces the risk of damage during operation. The provided shift rod makes it possible to place both devices on the control side, whereby the arrangement of the sensor device and the control device lying next to one another nevertheless enables a relatively short working unit to be realized. The control device can be arranged without problems where it does not hinder or impair the switching processes between the switching rod and the sensor device. In particular, options for axial adjustment of the sensor device can be provided if necessary, without the control device interfering. The control rod also allows easy adjustment of the switching time, since the switching section is arranged outside the linear motor in a clearly recognizable manner.

A linear drive device with a sensor device and a control device also emerges from DE-U-8603346. Piezoelectric transducers in the area of the housing faces serve as the control device. However, the control device formed by a slide valve is located laterally in the circumferential area of the working space receiving the piston, and the use of a switching rod is also not provided.

A linear motor results from JP-A-58/83202, the piston of which carries a further rod on the side opposite the actuating rod, which rod participates in the detection of the respective piston position. However, the sensor device designed as a detector is arranged axially following this rod on the outside of the device housing, as a result of which an increased axial overall length is established. A control device for motor control that can be actuated by means of the sensor device is not provided in this linear drive device.

Advantageous developments of the invention are listed in the subclaims.

The development according to claim 2 enables a simple and inexpensive construction. In the development according to claim 3, the space available for the devices on the control side of the linear motor is optimally used.

In a design according to claim 4, simple replacement of individual components in the event of a defect is possible. In the development according to claim 5, there is an optimum for the protective effect by the motor housing and the reduction in the overall width.

In the developments according to claims 6-9, both the control device and the sensor device are optimally protected, the linear drive device being given a relatively smooth surface on the outside, which considerably facilitates handling.

The development according to claim 10 allows a flexible adjustment of the desired switching time. The development according to claim 11 allows a largely dispensing with external lines, which reduces both the manufacturing and assembly costs and the susceptibility to failure.

The development according to claim 12 allows a simple, momentary connection of the individual components of the linear drive device to existing pressure medium and / or electrical lines, for example from a bus. This can be electrical and / or pneumatic multi-pin plug are used, so that mix-ups are excluded.

A particular advantage of the invention is that the working side of the linear drive device can remain free of any add-on components and there is sufficient space for the power take-off to be actuated. In addition, the individual components are outside the working area of the drive device, so that damage is excluded from the outset.

Fig. 1

eine erste Ausführungsform der erfindungsgemäßen Linear-Antriebseinrichtung in stark schematisierter Darstellungsweise im Längsschnitt,

Fig. 2

eine weitere Ausführungsform einer Linear-Antriebseinrichtung in einer der Fig. 1 entsprechenden Darstellungsweise,

Fig. 3

einen vergrößerten Ausschnitt eines weiteren Ausführungsbeispiels einer Linear-Antriebseinrichtung, ebenfalls schematisch und im Querschnitt, und

Fig. 4 und 5

verschiedene Anordnungsmöglichkeiten der Einrichtungskomponenten in schematischer Darstellung.

The invention is explained in more detail below with reference to the accompanying drawing. In this show:

Fig. 1

1 shows a first embodiment of the linear drive device according to the invention in a highly schematic representation in longitudinal section,

Fig. 2

1 shows another embodiment of a linear drive device in a representation corresponding to FIG. 1,

Fig. 3

an enlarged section of a further embodiment of a linear drive device, also schematically and in cross section, and

4 and 5

Different arrangement options of the furnishing components in a schematic representation.

The linear drive devices 1, 1 ', 1''shown in FIGS. 1 to 3 each contain a linear motor 2, which is expediently designed in the manner of a piston-cylinder unit. It has a motor housing 3 designed in the manner of a cylinder, which encloses a piston chamber 4, in which there is a piston 6, which can be moved back and forth in the axial direction according to double arrow 5. The piston 6 seals two cylinder spaces 7, 8 from one another in a sealed manner. The cross section of the piston chamber 4 is expediently circular-cylindrical, which simplifies production, and the outer circumference 9 of the motor housing 3 is also kept circular-cylindrical in the exemplary embodiment. But there are also also other design options without departing from the inventive concept, for example the outer circumference can be square or rectangular in cross-section, so that the motor housing 3 has a cuboid shape overall. For the sake of simplicity, the piston seals are not shown in the figures, their design is known to the person skilled in the art.

On one axial side 10 of the piston 6 there is an actuating rod 14 which runs coaxially to the piston chamber 4 and which crosses the associated cylinder chamber 8 in the longitudinal direction and penetrates the facing end wall 15 of the motor housing 3 with sealing and being guided so as to be displaceable to the surroundings. The end wall 15 can be an integral part of the motor housing 3, but it can also be a separate and in particular detachably fixed cover. The penetration point of the piston rod is indicated at 17; here too, seals have been omitted for the sake of simplicity.

The side on which the actuating rod 14 protrudes from the motor housing 3 represents the working side 18 of the linear drive devices 1, 1 ', 1˝. Here, the actuating rod 14 can be connected to a component to be moved or any power take-off, which in Fig. 1 is indicated by dashed lines at 19. If the two cylinder spaces 7, 8 are filled or ventilated with pressure medium in a suitable manner via corresponding connection openings 20, 21, the piston 6, together with the firmly attached actuating rod 14, performs an axial displacement movement indicated by a double arrow 5, within the scope of which the respective decrease in force 19 is moved in a corresponding manner. In the exemplary embodiment, the two cylinder spaces 7, 8 each represent work spaces, whereas in the case of modifications of the device according to the invention, not shown, one of the two spaces can also remain depressurized when the piston is returned to an initial position by being acted upon the actuating rod 14 is effected from the outside or via a return spring.

The control of the pressure medium supply and discharge with respect to the two cylinder spaces 7, 8 is carried out by a schematically indicated control device 22. This is preferably a valve device containing one or more valves, the actuation of which is carried out electrically, and corresponding electrical connection cables are shown in FIGS 1 and 2 indicated by dashed lines at 23. In addition, supply lines 24 are connected to the control device 22 (shown in broken lines in FIG. 2), which lead to a pressure medium source 25 and / or pressure medium sink 26, both of which are indicated schematically. In addition, there is also a pressure medium connection between the control device 22 and the two connection openings 20, 21 of the linear motor 2, which is accomplished via pressure medium lines 29 (indicated by dashed lines in FIG. 2), which, in the case of the exemplary embodiment according to FIG. 3, has a channel shape to be explained are designed as pressure medium channels 30.

The respective linear drive device 1, 1 ', 1˝ also has a sensor device 31 (not shown in Fig. 3) with which certain, previously definable displacement positions of the piston 6 and the actuating rod 14 can be detected in order to depend on certain Shift positions trigger functional processes of external or internal components. In the exemplary embodiment, the respective signal emitted by the sensor device 31 at the detection times is used internally in that the signals are used to actuate the control device 22. With the sensor device 31, for example, end positions of the piston 6, but also intermediate positions, can be detected.

It is now provided that the linear motor 2, the control device 22 and the sensor device 31 of the respective Linear drive device 1, 1 ', 1˝ are firmly connected to one another and thus form a compact work unit within which they can be handled together. The work unit thus represents a summary of three components 2, 22, 31 in the exemplary embodiments, which can be assembled uniformly at the place of use, so that complex individual assembly consisting of a large number of individual components is unnecessary. It is particularly advantageous that the control device 22 and the sensor device 31 are each arranged on the control side 28 of the linear motor 2 opposite the working side 18, so that the working side 18 can remain free of additional components, which improves the mounting options and damages the devices 22 , 31 is excluded by moving components.

If the three components 2, 22, 31 are detachably connected to one another, as in the exemplary embodiment, a quick exchange can be carried out in the event of a defect, and individual components can also be replaced if necessary in adaptation to the respective operating conditions.

The sensor device 31 shown in the exemplary embodiments according to FIGS. 1 and 2 is particularly advantageous. It contains several, for example two, sensors 32 which are designed as proximity switches which can be switched without contact. They work together with a switching section 33, which consists of magnetic material or at least contains magnetic components. The switching section 33 is fastened to one end region of a switching rod 34, which is fixed in particular in the same way as the actuating rod 14 with its opposite end on the piston 6 on the axial side 35 opposite the actuating rod 14. Both rods 14, 34 are preferably arranged coaxially to one another, and it can be two components which are connected to one another and on which the piston 6 is subsequently mounted. The rods 14, 34 can also be separate components which are firmly connected to the piston 6. In any case, the switching rod 34 penetrates the End wall 15 opposite axial end wall 36 of the motor housing 3, wherein guide and sealing devices, also not shown, are provided in the penetration area.

If the piston 6 is shifted according to the double arrow 5, the switching part 33 accordingly carries out a corresponding axial movement, and the sensors 32 arranged in the axial direction 5 laterally next to their movement path emit a signal at the point in time at which they are radially opposite the switching part 33.

In all the illustrated exemplary embodiments, the control device 22 and the sensor device 31 are accommodated in a common device housing 37, 37 '. In the exemplary embodiments according to FIGS. 1 and 3, the device housing 37 is a separate component with respect to the motor housing 3, which is fixed to the motor housing 3 and in particular is detachably connected here. It is attached to the motor housing 3 on the control side 28, e.g. as shown in the manner of a flange connection by means of screw connections 38. Since the same outer contour and the same transverse dimensions as for the motor housing 3 have been chosen for the device housing 37, the overall result is an elongated work unit which is narrow across the longitudinal direction. The device housing 37 preferably closes the installation space 39 for the devices 22, 31 from the outside, so that no contamination can occur and trouble-free operation is ensured. One end wall 36 of the motor housing 3 expediently forms a closure cover for the flanged-on device housing 37.

In one embodiment, not shown, the device housing is at least partially formed by the motor housing.

In the exemplary embodiment according to FIG. 2, a housing 40 is provided, which contains both the motor housing 3 and the control device 22 and the sensor device 31 protectively encased. Here, the enveloping housing 40 thus simultaneously forms the device housing 37 ', but which also contains the motor housing 3. In one embodiment, not shown, it is provided that both the motor housing 3 and a device housing surrounding the two devices 22, 31 are housed together in an enveloping protective housing.

In addition to the type of sensor already described above, other sensors can also be used. In particular, optical, electronic, inductive or pneumatic sensors are considered. However, it is advantageous in any case if the sensors 32 are adjustable in the direction of movement of the shift rod 34, so that the switching time can be variably adjusted. For this purpose, the sensors 32 in the embodiment according to FIG. 1 are adjustably arranged on a longitudinal guide 44 on the inside of the device housing 37. In the exemplary embodiment according to FIG. 2, the sensors 32 are arranged on the inside of the enveloping housing 40 and can also be adjustable in a corresponding manner.

Returning to FIG. 1, it can be seen that the control device 22 is expediently also fixed on the inside of the device housing 37. It is provided that the control device 22 and the sensor device 31 lie opposite one another transversely to the longitudinal direction 5 and in particular diametrically, so that a movement space 45 for the shift rod 34 remains between the two devices 22, 31. In this way, a short, compact arrangement can be achieved, and since the subunit of the working unit consisting of control device 22 and sensor device 31 is practically completely covered by the motor housing 3 in the longitudinal direction of the linear motor 2 from the working side 18, a slim, outward jagged arrangement. 4 schematically shows the arrangement of the linear motor 2, the control device 22 and the sensor device 31 within the work unit the linear drive device 1 is indicated, and a three-block arrangement can be seen in which the two devices 22, 31, which are arranged next to one another transversely to the longitudinal direction 5, follow at the same time in the axial direction of view 46 of the linear motor 2.

Another arrangement is shown schematically in FIG. 5, in which the linear motor 2, the sensor device 31 and the control device 22 also represent a three-block unit, the individual components of which are arranged one behind the other in the axial direction 5. This embodiment allows a further reduction in the transverse dimensions.

In the embodiment according to FIG. 2, in which the enveloping housing 40 simultaneously represents the device housing 37 ', the control device 22 and sensor device 31 are expediently fastened to the inside of this housing 40. The same applies to the motor housing 3, which can expediently be flanged to an end face 41 of the housing 40, the housing 40 having a through opening for the actuating rod 14.

In the exemplary embodiments according to FIGS. 1 and 2, the pressure medium connection between the control device 22 and the connection openings 20, 21 on the motor housing 3 takes place via loosely laid pressure medium lines 29. Because of the compact arrangement, the length of the lines can be kept very short, and through the individual housings they can be housed at least partially protected from external influences. Another variant is realized in the embodiment according to FIG. 3. There, the pressure medium lines 29 are designed in the form of pressure medium channels 30 which run in the wall of the motor housing 3 and partially of the device housing 37, so that external lines can be dispensed with if the control device 22 is arranged accordingly. This makes assembly considerably easier. It is also possible, to move to the motor housing 3 by the control device 22 via pressure medium lines, from where the connection to the cylinder spaces 7, 8 is then established via channels formed only in the motor housing 3.

The supply of the energy required for the operation of the linear drive devices 1, 1 ', 1˝ takes place from the outside via already mentioned pressure medium supply lines 24 and electrical connecting cables 23, which can also be responsible for the sensor device 31. In order not to have to lay each line or each cable individually, it is provided that connection options 47 shown in dashed lines are provided in FIGS. 1 and 2, which are preferably combined in the form of plug-type connection units and fixed to the device housing 37, 37 '. They are in permanent connection with the corresponding points of the two devices 22, 31 via the cables 23 or supply lines 24 and allow external lines 49, which lead to the pressure medium source 25, pressure medium sink 26 or e.g. an electronic control unit 48 (indicated by dashed lines). The design as a connection unit allows the lines 49 to be quickly detachably coupled within the framework of central plug connections, e.g. so-called pneumatic and / or electrical multi-pin plug devices can be used. Connection to a bus is therefore possible without any problems. It is advantageous in all of this if the connection options 47 are arranged on the connection side 50 opposite the working side 18, so that there is no increase in the overall width of the linear drive device even when the connection is established.

The invention thus combines various devices to form a structural unit, devices with three or four functional levels being present, depending on the embodiment. 1, 2 and 4, there are three levels, the first level being represented by the linear motor 2, the actuator, the second level by the control device (Processor) and sensor device existing subunit and the third level from the level of connection options 47, the bus level. 5 there are four levels, since the devices 22, 31 are arranged axially one after the other.

A major advantage of the invention is that the user can get a complete solution tailored to his problem from a single source, whereas in the past he had to order, store, assemble and maintain a large number of individual components in order to obtain the desired equipment. Commissioning is also much easier with the solution according to the invention, since practically only two plug connections (pneumatic and electrical multi-pin plug) have to be made in order to make the device ready for operation.

Claims (12)

1. Linear drive assembly, with a linear motor (2), in particular pneumatic and pressure-medium-operated, which has a housing (3) in which is located a piston (6) capable of movement in the axial direction (5) and connected to an actuating rod (18) protruding from the motor housing (3) on one operating side (18), with a control element (22), in particular in the form of a valve assembly, to control the motor, and with a sensor device (13) responding at particular positions of the actuating rod (14), in which the control element (22) and the sensor device (31) are located in that area of the control side (28) of the linear motor (2) opposite the operating side (18) and are permanently connected to the linear motor so as to form a single, easily-handled operating unit, characterized in that, on that piston side (35) opposite the actuating rod (14) is mounted a switch rod (34), permanently connected to and able to move with the assembly comprising the piston (6) and actuating rod (14), and having on that section of rod projecting from the motor housing (3) on the control side (28) one or more switch sections (33) working in conjunction with the sensor device (31) for its actuation, and that the control element (22) and the sensor device (31) are mounted consecutively alongside one another at right-angles to the axial direction (5), on the control side (28) of the linear motor (2) in the axial direction (5), With room for movement (45) for the sliding motion of the switch rod (34) between the two elements (22, 31).
2. Linear drive assembly according to claim 1, characterized in that the switch rod (34) is mounted coaxially to the actuating rod (14).
3. Linear drive assembly according to claims 1 or 2, characterized in that the control element (22) and the sensor device (31) lie diametrically opposite one another.
4. Linear drive assembly according to any of claims 1 to 3, characterized in that the linear motor (2), the control element (22) and the sensor drive (31) are detachable and in particular are joined to one another so as to be replaceable.
5. Linear drive assembly according to any of claims 1 to 4, characterized in that sub-unit containing the control element (22) and sensor device (31) is completely covered by the motor housing (3), viewed in the longitudinal direction (5) of the linear motor (2) from the operating side (18).
6. Linear drive assembly according to any of claims 1 to 5, characterized in that the control element (22) and the sensor device (31) are accommodated in a common equipment housing (37, 37').
7. Linear drive assembly according to claim 6, characterized in that the equipment housing is formed at least partially by the motor housing.
8. Linear drive assembly according to claim 6, characterized in that the equipment housing (37) is firmly but releasably secured to the motor housing (3) on the control side (28) of the linear motor (2), e.g. by a bolted connection (38) in the form of a flanged connection.
9. Linear drive assembly according to any of claims 6 to 8, characterized in that the motor housing (3) and the control element (22) together with the sensor device (31) are accommodated in a common encasing housing (40), whereby the two elements (22, 31) can also be mounted in an equipment housing located inside the encasing housing (40).
10. Linear drive assembly according to any of claims 1 to 9, characterized in that the sensor device (31) has one or more sensors (32), expediently adjustable in the direction of movement of the switch rod (34), in particular in the form of a non-contacting proximity sensor responding to the switch section (33).
11. Linear drive assembly according to any of claims 1 to 10, characterized in that the control element (22) is connected via pressure medium lines (29) with at least one of the two cylinder chambers (7, 8) separated from one another by the piston (6) of the motor housing (31), which run in the area of the housing, and may be in the form of pressure medium ducts (30) formed at least in part by the housing walls.
12. Linear drive assembly according to any of claims 1 to 11, characterized in that there are connections (47) linked to the control element (22) and the sensor device (31) for external electrical and/or pneumatic lines (49) or the like, located expediently on the connection side (50) of the operating unit opposite the operating side (18) and in particular combined to form plug or socket type connection units, which may if necessary be located on the equipment housing (37, 37').

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