EP4246000A1 - Piston cylinder unit, set comprising a piston-cylinder unit and a group of piston-cylinder units - Google Patents

Abstract

The invention relates to a piston-cylinder unit (1). A piston movement sensor (28) is arranged in a transverse bore (27) of a cylinder head (4) of the piston-cylinder unit (1). According to the invention, a positioning and/or alignment element (42) is supported in the transverse bore (27) on a base (47), on which the piston movement sensor (28) is in turn supported. The positioning and/or alignment element (42) specifies the axial position of the piston movement sensor (28) in the transverse bore (27). In addition, the positioning and/or alignment element (42) can specify the orientation of the piston movement sensor (28). The piston-cylinder unit (1) according to the invention is used, for example, for a work machine, construction machine, agricultural machine, a maritime machine, a wheel loader, an excavator, a tipper, a crane, a forklift or a lifting platform.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a piston-cylinder unit. The piston-cylinder unit can be used in a known manner in a work machine (in particular a construction machine, an agricultural machine, a maritime machine, a wheel loader, an excavator, a tipper, a crane, a forklift, a lifting platform or another work machine found in mechanical engineering). The piston-cylinder unit can be used, for example, to steer, support, push out, tilt, lift, lower or otherwise move a part of the work machine (in particular a tool, a rocker arm or another part of the work machine). It is preferably a hydraulic piston-cylinder unit.

Furthermore, the invention relates to a set with a piston-cylinder unit, whereby this set can also be used for a work machine.

Finally, the invention relates to a group of piston-cylinder units, the group having different subgroups and the piston-cylinder units of the different subgroups being designed and intended for different purposes. Such a group of piston-cylinder units can, for example, be manufactured, offered and sold by a manufacturer for different purposes, or offered and sold by a sales company, or stored and/or used by a customer for different purposes.

STATE OF THE ART

A generic piston-cylinder unit is from the publication DE 10 2019 122 121 A1 known. This well-known piston-cylinder unit is in Fig. 1 shown. In Fig. 1 is shown by means of break lines that the piston-cylinder unit 1 can actually be longer and only part of it is shown. The piston-cylinder unit 1 has a cylinder 2 with a cylinder tube 31, an interior 3 and a cylinder head 4. The cylinder tube 31 is connected to the cylinder head 4 via a weld seam 23. A bearing bush 5 is arranged in the area of the cylinder head 4. In DE 10 2019 122 121 A1 it is a hydraulic piston-cylinder unit 1, so that the interior 3 is filled with a hydraulic fluid 29, in particular oil. For this purpose, the cylinder 2 has a connection 6 and a connection 24. A hydraulic circuit, not shown here, with a hydraulic pump and changeover valves is connected to the connections 6, 24. The connections 6, 24 each open into an associated pressure chamber 32, 33. The pressure chambers 32, 33 are formed in the interior 3 and separated from one another by a piston 7. The piston 7 can be moved along the longitudinal central axis 30 of the cylinder 2 while sealing the pressure chambers 32, 33. Depending on the pressure generated by the hydraulic circuit at the connections 6, 24, an actuating force can be generated hydraulically in both directions along the longitudinal central axis 30, which acts on the piston 7, and with the thereby generated actuating movement of the piston 7, a change in the volume of the pressure chambers 32 , 33 can be brought about. Fig. 1 shows the position of the piston 7 moved all the way to the right, ie the retracted position of the piston-cylinder unit 1. The piston 7 is connected to a piston rod 8, at the outer end of which a piston rod eye 9 is arranged. The piston rod eye 9 also has a bearing bush 10. The bearing bushes 5, 10 serve to link the piston-cylinder unit 1 to the parts of the work machine that are to be moved relative to one another by means of the piston-cylinder unit 1 and/or on which the piston-cylinder unit 1 exerts a force should. The piston rod 8 is mounted in a translationally movable manner in the axial direction along the longitudinal central axis 30 by means of a guide bushing 11. A rod seal 12, an O-ring 13 and a support ring 14 are provided for storage and sealing. At the other axial end of the guide bushing 11, another O-ring 15, a wiper 16 and a plain bearing 17 are arranged. The piston 7 is arranged non-rotatably on the piston rod 8 and secured by means of a lock nut 18. Furthermore, an O-ring 19, a piston guide ring 20, a piston seal 21 and a further piston guide ring 22 are arranged on the piston 7. In this way, the piston 7 is mounted together with the piston rod 8 and the piston rod eye 9 in a translationally reciprocating and sealing manner in the cylinder tube 31 of the cylinder 2.

A partial chamber 25 of the pressure chamber 33 in the cylinder head 4 adjoins the part of the pressure chamber 33 which is delimited by the cylinder tube 31. The partial chamber 25 is connected to the connection 24. An axially extending sensor signal channel 26 opens into this partial chamber 25. The sensor signal channel 26 is also part of the pressure chamber 33 and is therefore filled with the hydraulic fluid. The sensor signal channel 26 is in turn connected to a transverse bore 27 which extends radially to the longitudinal central axis 30 in the cylinder head 4. The transverse bore 27 extends to the outer surface of the cylinder head 4 and can be connected to the environment by means of a compensating bore (not shown). A piston movement sensor 28 is arranged in the transverse bore 27. The piston movement sensor 28 is used to detect the axial position of the piston 7 in the cylinder 2 using high-frequency technology. For this purpose, the piston movement sensor 28 sends out a high-frequency signal, which hits the end face of the piston 7 or the piston rod 8 through the sensor signal channel 26 and through the partial chamber 25 as well as through the pressure chamber 33 and, after reflection through this end face, returns to the piston movement sensor 28 reached. The movement signal, in particular the path traveled by the end face, can then be determined from the reflected signal using high-frequency technology, in particular by evaluating the transit time. For the in Fig. 1 In the illustrated embodiment, the piston movement sensor 28 is acted upon by the hydraulic fluid. A sensor housing of the piston movement sensor 28 has seals with which the piston movement sensor 28 is sealed axially on both sides of the sensor signal channel 26 so that the hydraulic fluid cannot escape from the pressure chamber 33 and via the transverse bore 27. The piston movement sensor 28 here has a connection plug 34, which is carried by the sensor housing of the piston movement sensor 28 and extends radially out of the cylinder head 4. For further details please refer to the publication DE 10 2019 122 121 A1 referred to, which is made the subject of the present disclosure.

A further development of this piston-cylinder unit 1 is from the publication EP 3 957 868 A1 known. It is proposed here that a collimator is arranged in the beam path for the high-frequency signal, which serves to increase the measurement accuracy of the piston movement sensor. A collimator is understood to be an optical device for generating a beam path with parallel beams from previously non-parallel beams from divergent sources. In a first direction of radiation from a transmitting unit of the piston movement sensor to the end face of the piston or the piston rod, the collimator converts the non-parallel rays emitted by the piston movement sensor into parallel rays, which then also reflected in parallel from the face of the piston or piston rod. The reflected high-frequency beams are then bundled again by the collimator in the opposite second direction of radiation so that they can be received and evaluated by a receiving unit of the piston movement sensor. The collimator can also act as a type of filter that only or essentially focuses the high-frequency beams onto the piston movement sensor, which previously ran parallel to each other and to the longitudinal axis of the piston. This makes it possible to filter out high-frequency rays that do not come from the end piston crown surface, or at least not directly. Such undesirable rays are due to the fact that in reality the refraction of the collimator is not ideal, the rays are not emitted and received in an ideal point manner and the piston bottom surface is not ideally flat. The use of the collimator is intended to improve the signal-to-noise ratio. The collimator may include a dielectric lens. It is also possible to use several dielectric lenses or a Fresnel zone plate. The dielectric lens can have a convexly curved lens surface and/or consist of or have this material from a dielectric plastic or a dielectric ceramic, polytetrafluoroethylene, polyethylene or polypropylene. The dielectric lens preferably has a dielectric constant (permittivity) greater than that of air and greater than that of the hydraulic fluid in the piston-cylinder assembly. The permittivity can be, for example, between 20% and 50% greater than that of the hydraulic fluid in the piston-cylinder unit. The permittivity difference and the curvature of the dielectric lens are coordinated with one another. The dielectric lens may have a planar-convex lens shape. The convex side of the lens can face the piston. On the other hand, the planar side then faces the piston movement sensor. The collimator may be formed by the sensor housing or may be structurally separated from the piston movement sensor itself and the sensor housing. The piston movement sensor can also be designed as a compact built-in cartridge that contains both the sensor and the evaluation electronics. The piston movement sensor is arranged in the cross bore with an orientation such that the longest dimension of the piston movement sensor extends in the direction of the longitudinal axis of the cross bore. Away from the sensor signal channel, beam deflection elements can be arranged on a bottom of the partial chamber in order to avoid falsification of the measurement results. The collimator can be arranged in the sensor signal channel. For further details please refer to the publication EP 3 957 868 A1 referred to, which is made the subject of the present disclosure.

OBJECT OF THE INVENTION

• des Herstellungsaufwands und/oder
• der Bauteilvielfalt und/oder
• der Positionierung und Ausrichtung des Kolbenbewegungssensors relativ zu dem Zylinderkopf und/oder
• des Montage- und/oder Demontageaufwands und/oder
• der Variabilität der Einsatzbedingungen und der Anschlussbedingungen an die Arbeitsmaschine

verbessert ist.The present invention is based on the object of proposing a piston-cylinder unit with a piston movement sensor integrated in the cylinder head, which in particular relates to

• the manufacturing effort and/or
• the variety of components and/or
• the positioning and orientation of the piston movement sensor relative to the cylinder head and/or
• the assembly and/or disassembly effort and/or
• the variability of the operating conditions and the connection conditions to the working machine

is improved.

Furthermore, the invention is based on the object of proposing a set with a piston-cylinder unit, which can be used for the use of the piston-cylinder unit for different purposes.

Finally, the invention is based on the object of proposing a group of piston-cylinder units in which two subgroups are designed and intended for different purposes, but there is still a small variety of components.

SOLUTION

The object of the invention is achieved according to the invention with the features of the independent patent claims. Further preferred embodiments according to the invention can be found in the dependent patent claims.

DESCRIPTION OF THE INVENTION

The invention proposes a piston-cylinder unit which has a cylinder with a cylinder head, a piston which can be moved axially in the cylinder and a piston movement sensor. Here, the piston movement sensor is arranged in a transverse bore of the cylinder head that has a longitudinal axis. In this respect, the piston-cylinder unit can also be designed in the different variants according to the prior art mentioned at the beginning.

• sowohl in der vorbestimmten Position in der Querbohrung, die die axiale Position des Kolbenbewegungssensors entlang der Längsachse der Querbohrung beschreibt,
• als auch in der vorbestimmten Ausrichtung. die die Drehstellung des Kolbenbewegungssensors um die Längsachse der Querbohrung und damit die Richtung der Aussendung des Signals des Kolbenbewegungssensors beschreibt,

befindet. Dies erfordert für die aus dem Stand der Technik bekannten Ausführungsformen einen erhöhten Aufwand einerseits bei der Fertigung hinsichtlich der Fertigungstoleranzen und andererseits bei der Montage des Kolbenbewegungssensors in der Querbohrung des Zylinderkopfs.The embodiment according to the invention is based in particular on the knowledge that for the required accuracy of the measurement results of the piston movement sensor arranged in the transverse bore, it is crucial that the piston movement sensor and thus the transmitting and / or receiving unit for the high-frequency radiation (or another sensor signal)

• both in the predetermined position in the transverse bore, which describes the axial position of the piston movement sensor along the longitudinal axis of the transverse bore,
• as well as in the predetermined orientation. which describes the rotational position of the piston movement sensor about the longitudinal axis of the transverse bore and thus the direction of transmission of the signal from the piston movement sensor,

located. For the embodiments known from the prior art, this requires increased effort, on the one hand, in production in terms of manufacturing tolerances and, on the other hand, in mounting the piston movement sensor in the transverse bore of the cylinder head.

It is also possible that in the event that, according to the prior art, piston movement sensors and in particular sensor housings with different dimensions have to be produced in a series of piston-cylinder units with different dimensions (in particular different diameters of the cylinder tube and thus dimensions of the cylinder head). The reason for this is that the different dimensions of the piston-cylinder units result in different distances between the sensor signal channel inside the cylinder head and the connector on the outer surface of the cylinder head, which requires different lengths of the sensor housing.

In this area of tension, the invention proposes the following improvement: According to the invention, a positioning and/or alignment element is used. The positioning and/or alignment element ensures the correct positioning of the piston movement sensor in the direction of the longitudinal axis of the transverse bore, so that the positioning ensures that the high-frequency signal of the piston movement sensor is at the correct position Point passes through the sensor signal channel, any collimator and the pressure chamber and / or hits the end face of the piston or piston rod at the right place. The positioning and/or alignment element can alternatively or cumulatively also be used to specify the orientation of the piston movement sensor. If the positioning and/or alignment element is used cumulatively for positioning and aligning the piston movement sensor, it can be ensured in a simple and reliable manner that a deviation in the position and orientation of a transmitted high-frequency signal of the piston movement sensor lies within a predetermined small tolerance range.

According to the invention, the positioning and/or alignment element is arranged in the transverse bore and is supported in the transverse bore in the direction of the longitudinal axis of the transverse bore, namely in the assembly direction. This support can take place, for example, on a transverse surface, inclined surface, a step, taper or an annular collar of the transverse bore. The positioning and/or alignment element thus assumes a defined axial position in the transverse bore, which can already be specified during the production of the transverse bore, namely during the production of the transverse surface, inclined surface, step, taper or the annular collar.

The piston movement sensor is then supported on the positioning and/or alignment element in the direction of the longitudinal axis on the positioning and/or alignment element. Since the positioning and/or alignment element occupies a defined axial position in the transverse bore, the support of the piston movement sensor on the positioning and/or alignment element can ensure that the piston movement sensor also occupies a defined position in the transverse bore.

It is advantageous that in the event that the same piston movement sensor is used for piston-cylinder units of different dimensions, the same piston movement sensor can be used in the different piston-cylinder units, but this then requires an adjustment of the predetermined position of the piston movement sensor in the transverse bore can be done that the positioning and / or alignment element has different lengths.

As mentioned above, the support of the positioning and/or alignment element can be ensured by any transverse surface, inclined surface, step, taper or an annular collar, etc. of the transverse bore. For a particularly simple proposal of the invention, the Transverse bore can be designed as a blind hole, in which case the positioning and / or alignment element can be supported on a bottom (in particular the edge region of a conical bottom) of the blind hole. In this case, the position of the positioning and/or alignment element and thus also of the piston movement sensor can be specified by the depth of the blind hole.

It is possible that an alignment of the positioning and/or alignment element around the longitudinal axis of the transverse bore is predetermined. This can be done, for example, by a positive connection between the cross sections of the housing of the positioning and/or alignment element and the transverse bore. For example, the transverse bore can have a groove or recess (or a rib or a projection) running in the direction of the longitudinal axis, which cooperates in a form-fitting manner with a rib or a projection (or a groove or recess) of the housing of the positioning and/or Alignment element. However, it is also possible for the alignment of the positioning and/or alignment element to be ensured in that an end face of the housing of the positioning and/or alignment element facing the bottom of the transverse bore has an eccentric recess (or a projection) which engages in one corresponding projection (or a recess) of the floor.

A further aspect of the invention is dedicated to securing the positioning and/or alignment element within the transverse bore. It is suggested that at least one security element be present. The securing element serves to secure the longitudinal position of the positioning and/or alignment element in the transverse bore. The securing element thus serves to ensure that both the positioning and/or alignment element and the piston movement sensor are in their predetermined position and remain in operation. Alternatively or cumulatively, it is possible for the at least one securing element to be used to secure the alignment of the positioning and/or alignment element about the longitudinal axis of the transverse bore (and thus possibly also to secure the alignment of the piston movement sensor).

There are a variety of options for the type of design of the security element. For example, a safety bolt, a safety pin, a snap connection, a tongue and groove connection to secure alignment, etc. can be used. For a very simple embodiment, the securing element is a screw. The screw can extend parallel to the longitudinal axis of the transverse bore. It is possible, for example, that the Screw through a hole from the other side extending through the bottom of the blind hole. However, it is also possible for a screw, which forms the securing element, to extend radially to a longitudinal axis of the transverse bore. In any case, the screw is accessible from the outside of the cylinder head and extends through a hole to the positioning and/or alignment element, where the screw is then screwed to an internal thread of the positioning and/or alignment element. It is also possible for the positioning and/or alignment element to have both an end-side threaded hole, which is used when the screw extends parallel to the longitudinal axis of the transverse hole, and a radially oriented threaded hole for assembly in the event that the screw extends radially to the longitudinal axis of the transverse bore.

The positioning and/or alignment element and the piston movement sensor preferably lie directly against one another via contact surfaces. These contact surfaces can ensure the correct positioning of the piston movement sensor in the direction of the longitudinal axis of the transverse bore.

It is possible that not only the axial position of the piston movement sensor in the transverse bore must be specified. Rather, it may also be necessary for an orientation of the piston movement sensor to be specified with regard to its angle of rotation about the longitudinal axis of the transverse bore. The specification of the angle of rotation may be necessary, for example, so that a sensor signal emitted by the piston movement sensor can pass through a sensor signal channel and/or strike an end face of the piston or piston rod at a defined location and/or under a defined orientation. This alignment can be specified, for example, in that the piston movement sensor interacts positively in the circumferential direction with the transverse bore, so that on the one hand the alignment is specified via the positive connection and on the other hand, such a specified alignment is also maintained during operation. For example, the transverse bore can have a groove or a recess running in the direction of the longitudinal axis, in which a projection or a rib of the housing of the piston movement sensor is then arranged. Conversely, it is possible for the transverse bore to have a rib or a projection running in the direction of the longitudinal axis, which engages in a groove or recess in the housing of the piston movement sensor. It is also possible that the transverse bore on the one hand and the housing of the piston movement sensor on the other hand are corresponding non-round ones, for example. have elliptical cross-sections that ensure precise insertion in the correct orientation.

For one proposal of the invention, the contact surfaces of the positioning and/or alignment element on the one hand and of the piston movement sensor on the other hand are connected to one another via a positive connection in the circumferential direction around the longitudinal axis of the transverse bore. This positive connection then limits or even specifies the possible relative orientations of the piston movement sensor on the one hand and of the positioning and/or alignment element (hereinafter referred to as contact elements) on the other hand. There are a variety of options for this form fit. To give just a few examples that do not limit the invention, one of the two contact elements can have a projection that engages in a recess in the other contact element. It is also possible for an end face of a contact element to have a step that interacts in a form-fitting manner with a corresponding step of the other contact element to ensure anti-twist protection and specification of the alignment.

A further aspect of the invention is dedicated to enabling dismantling of the piston movement sensor, which can be done, for example, for maintenance purposes, in the event of a defect in the piston movement sensor, for cleaning purposes or to use another piston movement sensor with a different measuring range or a different measuring accuracy. In this case, it is advantageous if the piston movement sensor is detachably held on the positioning and/or alignment element, but the connection still ensures a certain holding force. It is advantageous if only a dismantling force that exceeds a threshold value of the holding force of the connection has to be applied for dismantling.

For one embodiment of the invention, the piston movement sensor is connected to the positioning and/or alignment element via a latching connection. In this case, the latching force of the latching connection specifies the threshold value for the holding force - if the fitter applies a dismantling force to the piston movement sensor that is greater than the latching force, the latching connection can be released and the piston movement sensor can be dismantled from the positioning and / or alignment element and removed from the cross hole.

For another embodiment, a permanent magnet is used which generates a magnetic holding force between the piston movement sensor and the positioning and/or alignment element. In this case, the threshold value for the holding force for dismantling is determined by the magnetic force. Within the scope of the invention, it is also possible for the piston movement sensor and the positioning and/or alignment element to each have a permanent magnet, between which the magnetic force is then generated.

For disassembly, the installer can apply the required disassembly force in any way. For one proposal of the invention, the piston movement sensor has a dismantling driver in the area of an end face on the side that faces away from the positioning and/or alignment element. The dismantling driver can be coupled with a dismantling tool. The required dismantling force can be applied to the piston movement sensor using the dismantling tool and the dismantling driver. For example, the dismantling driver can be designed as a type of hook connection into which a counter-hooking dismantling tool is hooked, the dismantling driver and the dismantling tool can form a locking connection or the dismantling driver and the dismantling tool can be connected to one another via a permanent magnet. For a special proposal of the invention, the dismantling driver is an internal thread of the piston movement sensor. A dismantling rod can then be screwed into this internal thread, so that the required dismantling forces can then be applied to the piston movement sensor via the dismantling rod protruding from the cross hole after screwing in.

The internal thread can be formed from a solid material of the sensor housing. For one proposal of the invention, the internal thread is formed by a thread insert. This thread insert can then be injected into a sensor housing of the piston movement sensor or pressed into a hole in the sensor housing. The use of such a thread insert is advantageous, for example, if the sensor housing is made of a material in which the production of an internal thread does not provide the required strength. In this case, a stronger material, in particular metal, can be selected for the material of the thread insert. The stronger material can then provide the required strength for the threaded connection in the area of the thread. On the other hand, the threaded insert can have an enlarged outer surface, which then enables a large-area connection and power transmission to the sensor housing.

In principle, it is possible for a connection plug to be formed directly by or held on the sensor housing and to protrude outwards from the transverse bore and the cylinder head, where the connection plug can then be connected to the required connection cables. For one proposal of the invention, the piston movement sensor is connected to a housing plug via a sensor cable. The sensor unit therefore has two sub-units, namely the piston movement sensor and the housing plug, which are flexibly connected to one another via the sensor cable. The connection via the sensor cable enables a simple adjustment for the use of the same piston movement sensor and the same housing plug for piston-cylinder units with different dimensions, in that the sensor cable can then be installed more or less curved or stretched for the different installation situations. On the other hand, under certain circumstances, the sensor housing can be designed to be less massive or shorter, since the sensor housing does not have to bridge the entire radial area from the actual measuring area to the connecting plug, but rather a partial area can be bridged by the sensor cable.

It is particularly advantageous if the sensor cable is detachably connected to the piston movement sensor and/or the housing plug. This enables, for example, a separate assembly of initially only the piston movement sensor, then the connection of the sensor cable and finally the assembly of the housing plug, whereby a corresponding separate disassembly can also take place. Furthermore, it is possible that, for example for maintenance purposes or in the event of a defect, only a piston movement sensor or a housing plug needs to be replaced, while the remaining part of the piston movement sensor and the housing plug can then continue to be used.

For a special proposal of the invention, however, the detachable connection to the sensor cable also makes it possible for the same piston movement sensor to be used with different housing plugs in order to enable adaptation to different applications that require different housing plugs.

It is also advantageous if the housing plug is detachably connected to the cylinder head. In one proposal of the invention, the housing plug has a flange for this purpose. The flange can then be screwed to the cylinder head, enabling a reliable connection between the housing plug and the cylinder head.

It is even possible for the flange to be screwed to the cylinder head in different orientations of the housing plug around the longitudinal axis of the transverse bore, which allows the respective installation conditions to be taken into account.

It is possible that any number of different housing plugs can be used within the scope of the invention. On the one hand, the housing plugs can have a different shape. It is possible that a first housing plug is designed to be straight, while a second housing plug that can be used within the scope of the invention is designed to be L-shaped. In this case, the housing plug can have two angled legs. One leg then extends into the interior of the transverse bore of the cylinder head. The sensor cable can then be connected in the area of one end face of this leg. On the other hand, the other leg extends on the outside of the cylinder head. It is possible for this leg to extend radially to the longitudinal axis of the transverse bore. For an installation situation, the leg is oriented parallel to the longitudinal central axis of the cylinder of the piston-cylinder unit, which is advantageous for some applications. In this case, the end face of the latter leg can be used to connect a connection cable.

1. a) Möglich ist hierbei beispielsweise, dass ein erster Typ eines Gehäusesteckers als sogenannter DIN-Stecker ausgebildet ist. Beispielsweise kann es sich um einen DIN-Stecker M12 handeln, der 5-polig ausgebildet sein kann. Derartige DIN-Stecker sind in den Normen DIN 41524 (3- und 5-polig), DIN 45322 (5-polig mit 60° Abstand), DIN 45326 (8-polig) und DIN 45329 (7-polig) (diese Normen ersetzt durch EN 60130-9) beschrieben.
   Für diesen ersten Typ des Gehäusesteckers können dann wiederum unterschiedliche Untertypen verwendet werden, die sich durch die Belegung der Anschlusspins unterscheiden:
   • aa) Für einen ersten Untertyp ist ein erster Pin nicht belegt. Ein zweiter Pin ist mit der Funktion VDC (Spannungsversorgung des Kolbenbewegungssensors) belegt. Ein dritter Pin ist mit der Funktion GND (Erde) belegt. Ein vierter Pin ist mit dem Datenbus CAN HI belegt, während ein fünfter Pin mit einem Datenbus CAN LO belegt ist.
   • ab) Für einen zweiten Untertyp des ersten Typs kann ein erster Pin nicht belegt sein, ein zweiter Pin mit VDC belegt sein, ein dritter Pin mit GND belegt sein, ein vierter Pin mit einem pulsweitenmodulierten Signal belegt sein und ein fünfter Pin nicht belegt sein.
2. b) Für einen zweiten Typ des Gehäusesteckers ist der Gehäusestecker als sogenannter Deutsch-Stecker ausgebildet, wobei es sich beispielsweise um einen Deutsch-Stecker DT 04 handeln kann mit vier Pins.
   Auch für den zweiten Typ sind unterschiedliche Untertypen möglich:
   • ba) So kann beispielsweise ein erster Untertyp des zweiten Typs mit einem ersten Pin ausgestattet sein, der die Funktion VDC gewährleistet. Der zweite Pin ist mit der Funktion CAN LO belegt, ein dritter Pin mit der Funktion GND sowie ein vierter Pin mit der Funktion CAN HI.
   • bb) Hingegen kann für einen zweiten Untertyp des zweiten Typs ein erster Pin mit der Funktion VDC belegt sein, ein zweiter Pin mit der Funktion GND belegt sein, ein dritter Pin mit der Funktion PWM belegt sein und ein vierter Pin nicht belegt sein.

In addition to the use of housing plugs of different shapes in the piston-cylinder unit according to the invention, the housing plugs can alternatively or cumulatively also be equipped with different connection geometries and pin assignments.

1. a) It is possible, for example, for a first type of housing plug to be designed as a so-called DIN plug. For example, it can be an M12 DIN plug, which can be 5-pin. Such DIN plugs are in the standards DIN 41524 (3- and 5-pin), DIN 45322 (5-pin with 60° spacing), DIN 45326 (8-pin) and DIN 45329 (7-pin) (these standards replace described by EN 60130-9).
   For this first type of housing connector, different subtypes can then be used, which differ in the assignment of the connection pins:
   • aa) For a first subtype, a first pin is not assigned. A second pin is assigned the VDC function (voltage supply for the piston movement sensor). A third pin is assigned the GND (earth) function. A fourth pin is with the CAN HI data bus is occupied, while a fifth pin is occupied by a CAN LO data bus.
   • ab) For a second subtype of the first type, a first pin can be unoccupied, a second pin can be assigned VDC, a third pin can be assigned GND, a fourth pin can be assigned a pulse width modulated signal and a fifth pin can be unoccupied.
2. b) For a second type of housing plug, the housing plug is designed as a so-called Deutsch plug, which can be, for example, a Deutsch plug DT 04 with four pins.
   Different subtypes are also possible for the second type:
   • ba) For example, a first subtype of the second type can be equipped with a first pin that ensures the VDC function. The second pin is assigned the CAN LO function, a third pin is assigned the GND function and a fourth pin is assigned the CAN HI function.
   • bb) On the other hand, for a second subtype of the second type, a first pin can be assigned the VDC function, a second pin can be assigned the GND function, a third pin can be assigned the PWM function and a fourth pin can be unoccupied.

According to the invention, it is possible for one and the same piston movement sensor to be combined via the detachable sensor cable, depending on the requirements and intended use, with housing plugs of different geometries and angles of the legs of the housing plug and/or housing plugs of the different types and subtypes mentioned.

For the embodiments known from the prior art, the piston movement sensor was hydraulically connected to the pressure chamber via the sensor signal channel, so that the piston movement sensor itself was acted upon by the hydraulic fluid. This required that the sensor housing of the piston motion sensor be equipped with annular grooves on both sides of the sensor signal channel to seal the piston motion sensor in the cross bore. If the piston movement sensor needs to be replaced for these embodiments, the hydraulic fluid must be drained, otherwise the hydraulic fluid for the dismantled piston movement sensor would escape from the transverse bore. For an embodiment of the piston-cylinder unit, the invention proposes that the transverse bore is hydraulically separated from the pressure chamber via a sealing element. In this case, the piston movement sensor can be dismantled from the transverse bore without the hydraulic fluid being able to pass over to the transverse bore, since the passage is blocked by the sealing element. Here, the sealing element is preferably designed and the material thereof selected so that it allows the high-frequency radiation from the piston movement sensor to pass through and, if possible, does not impair it in an undesirable way.

For a particular proposal of the invention, the sealing element is designed as a collimator, so that in this case the collimator is multifunctional, since it ensures the desired beam bundling and parallel alignment and also acts as a sealing element. It is possible for the collimator to have at least one annular groove in the area of its outer surface, into which a sealing ring, in particular an O-ring, is inserted, which interacts with a seal with the sensor signal channel in which the collimator is arranged.

A further solution to the problem on which the invention is based is a set which has a piston-cylinder unit, as explained previously. The set contains at least two housing plugs. These two housing connectors are designed and intended for different purposes. Thus, for example, the two different housing plugs can be housing plugs of the previously explained different geometries, types and/or subtypes. The two housing plugs can then optionally be inserted into the transverse bore and the selected housing plug can be attached to the housing of the piston-cylinder unit. The selected housing plug is then connected to the piston movement sensor using the sensor cable. In this way, a set can be provided for the customer with which the same piston movement sensor can be connected to different housing connectors in different installation situations, which can expand the variety of applications and reduce the variety of components.

A further solution to the problem on which the invention is based is a group of piston-cylinder units, as explained above. The group points out two different subgroups of piston-cylinder units, with these two subgroups then being designed and intended for different purposes. In the first subgroup, the piston-cylinder units have first housing plugs, while in the second subgroup the piston-cylinder units have the second housing plugs. The first housing plugs and the second housing plugs are designed and intended for different purposes, which means that the piston-cylinder units of the two subgroups are also designed and intended for different purposes. The first housing plugs and second housing plugs can differ from one another, for example, by the different geometries, types and/or subtypes explained above. Identical piston movement sensors are then present in the piston-cylinder units of the first subgroup and the piston-cylinder units of the second subgroup. For example, such a group with the different subgroups can be offered by a manufacturer or a sales company, so that the customer can then purchase the piston-cylinder units of the first subgroup or the second subgroup depending on the desired application. However, it is also possible for an end customer, a repair shop or a manufacturer of a work machine to have such a group of piston-cylinder units available for different purposes.

Advantageous developments of the invention result from the patent claims, the description and the drawings.

The advantages of features and combinations of several features mentioned in the description are merely examples and can have an alternative or cumulative effect without the advantages necessarily having to be achieved by embodiments according to the invention.

With regard to the disclosure content - not the scope of protection - of the original application documents and the patent, the following applies: Further features can be found in the drawings - in particular the geometries shown and the relative dimensions of several components to one another as well as their relative arrangement and operative connection. The combination of features of different embodiments of the invention or of features of different patent claims is also possible, deviating from the selected relationships of the patent claims, and is hereby encouraged. This also applies to features that are shown in separate drawings or are mentioned in their description. These features can also be combined with features of different patent claims. Likewise, features listed in the patent claims may be omitted for further embodiments of the invention, but this does not apply to the independent patent claims of the granted patent.

The features mentioned in the patent claims and the description are to be understood in terms of their number in such a way that exactly this number or a larger number than the number mentioned is present, without the need for an explicit use of the adverb "at least". For example, when we talk about an element, this should be understood to mean that there is exactly one element, two elements or more elements. The features listed in the patent claims can be supplemented by further features or can be the only features that the subject of the respective patent claim has.

The reference symbols contained in the patent claims do not represent a limitation on the scope of the subject matter protected by the patent claims. They merely serve the purpose of making the patent claims easier to understand.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1

zeigt in einem Längsschnitt eine Kolben-Zylinder-Einheit gemäß dem Stand der Technik.

Fig. 2

zeigt in einem Teillängsschnitt eine Kolben-Zylinder-Einheit im Bereich des Zylinderkopfs.

Fig. 3

zeigt in einer räumlichen Explosionsansicht den Zylinderkopf gemäß Fig. 2 mit zugeordneten Bauelementen.

Fig. 4

zeigt in einer räumlichen Ansicht einen Kolbenbewegungssensor und ein Positio-nier- und/oder Ausrichtelement.

Fig. 5

zeigt in einer räumlichen Ansicht einen Gehäusestecker des Typs DIN-Stecker (5-polig) mit Sensorkabel.

Fig. 6

zeigt den Gehäusestecker mit Sensorkabel gemäß Fig. 5 in einer Seitenansicht.

Fig. 7

zeigt in einer räumlichen Ansicht einen Gehäusestecker des Typs Deutsch-Stecker (4-polig) mit Sensorkabel.

Fig. 8

zeigt den Gehäusestecker gemäß Fig. 7 in einer Seitenansicht.

The invention is further explained and described below using preferred exemplary embodiments shown in the figures.

Fig. 1

shows a longitudinal section of a piston-cylinder unit according to the prior art.

Fig. 2

shows a partial longitudinal section of a piston-cylinder unit in the area of the cylinder head.

Fig. 3

shows the cylinder head in a spatial exploded view Fig. 2 with assigned components.

Fig. 4

shows a three-dimensional view of a piston movement sensor and a positioning and/or alignment element.

Fig. 5

shows a spatial view of a housing connector of the DIN plug type (5-pin) with sensor cable.

Fig. 6

shows the housing connector with sensor cable according to Fig. 5 in a side view.

Fig. 7

shows a three-dimensional view of a housing plug of the Deutsch plug type (4-pin) with sensor cable.

Fig. 8

shows the housing connector according to Fig. 7 in a side view.

FIGURE DESCRIPTION

Unless otherwise follows from the following, for the embodiments according to the invention, this can be referred to at the beginning as to the prior art and to the embodiment according to Fig. 1 What has been said applies accordingly, including the further disclosure in the publications DE 10 2019 122 121 A1 and EP 3 957 868 A1 can be used within the scope of the invention.

Fig. 2 shows a piston-cylinder unit 1 in the area of the cylinder head 4. A sensor signal channel 26 opens into the pressure chamber 33 of the piston-cylinder unit 1. A collimator 35 is arranged in the sensor signal channel 26. The collimator 35 has a flat end face on the side facing the piston movement sensor 28, which is oriented transversely to the longitudinal central axis 30. With regard to the longitudinal central axis 30, the collimator 35 is designed to be rotationally symmetrical on the other side, wherein the collimator 35 can, for example, have a curved and in particular parabolic longitudinal section, as shown. The collimator 35 has an annular groove 36 in which a sealing element 37, here an O-ring 38, is arranged. The sealing element 37 ensures a hydraulic seal between the inner wall of the sensor signal channel 26 and the collimator 35. The sensor signal channel 26 has a circumferential shoulder 39. If the pressure chamber 33 is pressurized with hydraulic pressure, the pressure acts on the spherical end face facing the piston 7 Hydraulic pressure to a hydraulic force that presses the collimator 35 against the shoulder 39. This pressure of the collimator 35 on the shoulder 39 and/or the effect of the sealing element 37 can ensure that the transverse bore 27 is not exposed to hydraulic fluid and therefore no additional sealing measures need to be taken in the transverse bore 27. On the other hand, possible This seal means that dismantling of the piston movement sensor 28 is possible without hydraulic fluid being able to escape from the transverse bore 27.

As shown in the exploded view in Fig. 3 As can be seen, a securing element 40 in the form of a screw 41, a positioning and/or alignment element 42, the piston movement sensor 28, a sensor cable 43 and a housing plug 44 are mounted in the transverse bore, the housing plug 44 being attached to a housing 46 of the housing via fastening screws 45 Cylinder head 4 is attached.

According to Fig. 4 the positioning and/or alignment element 42 is cylindrical with a diameter such that the positioning and/or alignment element 42 can be inserted precisely into the transverse bore 27. The underside of the positioning and/or alignment element 42 is flat for the illustrated embodiment. The underside of the positioning and/or alignment element 42 rests on a bottom 47 of the transverse bore 27, which is designed here as a blind hole.

On the side facing the piston movement sensor 28, the positioning and/or alignment element 42 is basically flat, but is designed with a step 48. On this side, the positioning and/or alignment element 42 has a (here cylindrical) receptacle 49, in which a permanent magnet 50 is accommodated, which can be glued to the receptacle 49 or pressed into it. The outer surface of the permanent magnet 50 is arranged flush with a partial surface of the end face of the positioning and/or alignment element 42 away from the step 48.

On the side facing away from the piston movement sensor 28, the positioning and/or alignment element 42 has an internal thread 51 arranged eccentrically to the longitudinal axis 53 of the transverse bore 27. In the aligned position of the positioning and/or alignment element 42 installed in the transverse bore 27, this is aligned Internal thread 51 of the positioning and/or alignment element 42 with an eccentric bore 52 opening into the transverse bore 27, through which the screw 41 extends from the outside through the housing 46. In this way, the positioning and/or alignment element 42 is fixed in the correct position and orientation.

It is possible that the positioning and/or alignment element 42 also has a transverse bore 54, possibly with an internal thread. It's not like in Fig. 2 shown a hole 52 is present or used, which is oriented parallel to the longitudinal axis 53 of the transverse hole 27, but rather a hole is provided in the housing 46, which is vertical to the plane of the drawing Fig. 2 is oriented, as an alternative to the attachment via the screw 41, the positioning and/or alignment element 42 can be attached via a screw which is vertical to the plane of the drawing Fig. 2 extends through the housing 46 and is screwed in the inner end region to the transverse bore 54 of the positioning and / or alignment element 42.

The piston movement sensor 28 has a sensor housing 55, the external geometry of which is cylindrical with a diameter such that the sensor housing 55 can find a precise fit in the transverse bore 27. Compared to this external geometry, the sensor housing 25 has recesses in which the electronic component and the transmitting and/or receiving unit for the high-frequency signal are arranged.

On the side facing the positioning and/or alignment element 42, the sensor housing 55 has a step 56 which is designed corresponding to the step 48 of the positioning and/or alignment element 42. Away from the steps 48, 56, the positioning and/or alignment element 42 and the sensor housing 55 form contact surfaces 57, 58 which are oriented transversely to the longitudinal axis 53, in the area in which these components rest against one another in the direction of the longitudinal axis 53, which predetermines the axial position of the piston movement sensor 28 is.

On the other hand, the steps 48, 56 form a positive fit against rotation about the longitudinal axis 53, which predetermines the orientation of the piston movement sensor 28. In the relative orientation predetermined by the steps 48, 56, a corresponding receptacle 59 with a permanent magnet 60 is provided on the sensor housing 55, aligned with the receptacle 49 and the permanent magnet 50 of the positioning and/or alignment element 42. The permanent magnet 60 is also fixed in the receptacle 59, for example by gluing or pressing it in. The magnetic force between the permanent magnets 50, 60 secures the system and thus the position and alignment between the positioning and/or alignment element 42 and the piston movement sensor 28.

On the side facing away from the positioning and/or alignment element 42, the sensor housing 55 has a flat end face 61. In the area of this end face 61, the piston movement sensor 28 has an internal thread 62, which is formed here by a thread insert 63 injected into the sensor housing 55. The internal thread 62 forms a dismantling driver 64.

Furthermore, a plug receptacle 65 is provided in the end face 61, into which a plug 66 of the sensor cable 43 can be inserted. Preferably, the format of the plug 66 and the plug receptacle 65 is a 5-pin pico-clasp connection (registered trademark).

5 and 6 show a housing plug 44-I, where "I" here indicates that it is a housing plug of a first type (see the explanations for the first type above).

As in Fig. 6 can be seen, the housing plug 44-I is L-shaped with a leg 67 and a leg 68 which is angled here at an angle of 90 °. A plug receptacle is provided in the end face of the leg 68, into which a plug 69 of the sensor cable 43 can be plugged in. Preferably, both the plug receptacle and the plug 69 have the “pico-clasp” format.

When oriented coaxially to the longitudinal axis 53, the outer end region of the leg 68 extends into the transverse bore 27. The end region of the leg 68 can have a circumferential bead 70 or a sealing element. In the state inserted into the transverse bore 27, the bead 70 creates a frictional, elastically prestressed securing of the leg 68 in the transverse bore 27. In addition, a seal can be provided here.

In the exit area of the leg 68 from the housing 46 of the cylinder head 4, the leg 68 has a circumferential flange 71. The flange 71 is accommodated in a corresponding receptacle or recess in the housing 46. The flange 71 has through holes oriented parallel to the longitudinal axis 53, via which the flange 71 can be screwed to corresponding threaded holes in the housing 46. Preferably, several holes are provided in the flange 71 and threaded holes in the housing 46, so that the housing plug 44-I can be screwed to the housing 46 in different orientations about the longitudinal axis 53.

The end region of the leg 67 forms the connecting plug 34, which enables the connecting cable to be connected.

For the housing plug 44-I, the connecting plug 34 has, as shown in particular in Fig. 5 can be seen via 5 pins 72. This is in particular a connection plug 34 of the type “DIN plug M 12 5-pin”. Here, the housing plug 44-I of the first type can be designed according to the subtypes explained at the beginning.

7 and 8 show a housing plug 44-II, where "II" here indicates that it is a housing plug of a second type. Here, the housing plug 44-II of the second type can be designed according to the subtypes explained at the beginning.

The electronic components are integrated into the housing plug 44 in order to modify the transmitted signals from the plug 69 to the connecting plug 34.

The piston movement sensor 28 is used to directly measure the stroke of the piston 7 or the piston rod 8 within the piston-cylinder unit 1. The piston movement sensor 28 is preferably based on a non-contact measuring radar system in which the transit time between a transmitting unit and the end face of the piston 7 or the piston rod 8 and the reflected signal is evaluated back to a receiving unit. The position and/or speed can then be determined from the transit time with high accuracy and robustness.

The piston-cylinder unit 1 with the integrated piston movement sensor 28 is preferably designed in accordance with protection class IP69K.

It is possible that the piston movement sensor 28 can be used to determine a stroke that is in the range of 10 mm to 2,000 mm, for example 30 mm to 1,800 mm or 40 mm to 1,600 mm. Here, for example, a resolution in the range of 0.2 mm to 4 mm, for example 0.5 to 2 mm or 0.8 to 1.5 mm, can be achieved.

Another advantage of sealing the sensor signal channel 26 by a sealing element or a multifunctional collimator 35 is that the high hydraulic pressures, which also 100 bar to 600 bar cannot lead to deformation, stress and damage to the piston movement sensor 28, the sensor housing 55 and the electronic components of the piston movement sensor 28.

The pico-clasp connector used for the sensor cable 43 and its connection to the piston movement sensor 28 and the housing plug 44 can have five pins, which can be assigned GND, VDC, CAN LO, CAN HI and an analog signal.

The analog signal can be used to transmit a pulse width modulated signal (PWM), with the measurement signal being transmitted via pulse width modulation. Alternatively, it is possible that a voltage or a current that is proportional to the measurement signal is transmitted as an analog signal.

The piston movement sensor 28 may not only measure the stroke and/or the speed of the piston 7 or the piston rod 8. It is possible that, alternatively, other measured variables (such as the temperature) can also be measured, transmitted and/or evaluated. The temperature can be used for temperature compensation.

It is also possible that a bidirectional transmission is possible via the housing plug 44, which also allows a software update of the piston movement sensor 28 to take place and update functions to be carried out.

If a PWM signal is transmitted, it preferably has a frequency of 500 Hz. The duty cycle provides information about the measured path of the piston. For example, if the piston is fully retracted, the duty cycle can be 5%, while for the fully extended state of the piston, the duty cycle can be 95%.

REFERENCE SYMBOL LIST

1

Piston-cylinder unit

2

cylinder

3

inner space

4

cylinder head

5

Bearing bushing

6

Connection

7

Pistons

8th

Piston rod

9

Piston rod eye

10

Bearing bushing

11

Guide bushing

12

Rod seal

13

O-ring

14

Support ring

15

O-ring

16

scraper

17

bearings

18

lock nut

19

O-ring

20

Piston guide ring

21

Piston seal

22

Piston guide ring

23

Weld

24

Connection

25

Partial chamber

26

Sensor signal channel

27

Cross hole

28

Piston movement sensor

29

Hydraulic fluid

30

Longitudinal center axis of the cylinder

31

cylinder tube

32

Pressure chamber

33

Pressure chamber

34

Connection plug

35

Collimator

36

Ring groove

37

Sealing element

38

O-ring

39

Paragraph

40

Security element

41

screw

42

Positioning and/or alignment element

43

Sensor cable

44

Housing connector

45

Fastening screws

46

Housing

47

Floor

48

Level

49

Recording

50

Permanent magnet

51

inner thread

52

drilling

53

Longitudinal axis

54

Cross hole

55

Sensor housing

56

Level

57

Contact surface

58

Contact surface

59

Recording

60

Permanent magnet

61

face

62

inner thread

63

Thread insert

64

Dismantling driver

65

Plug receptacle

66

Sensor cable connector

67

leg

68

leg

69

Sensor cable connector

70

bead

71

flange

72

Pin code

Claims (15)

Piston-cylinder unit (1) a) with a cylinder (2) having a cylinder head (4), b) with a piston (7) which can be moved axially in the cylinder (2) and c) with a piston movement sensor (28), d) wherein the piston movement sensor (28) is arranged in a transverse bore (27) of the cylinder head (4) having a longitudinal axis (53), characterized in that
e) a positioning and/or alignment element (42) is supported in the transverse bore (27) in the direction of the longitudinal axis (53) of the transverse bore (27) and the piston movement sensor (28) in the direction of the longitudinal axis (53) on the positioning and / or alignment element (42) is supported. Piston-cylinder unit (1) according to claim 1, characterized in that the transverse bore (27) is a blind hole and the positioning and/or alignment element (42) is supported on a base (47) of the blind hole. Piston-cylinder unit (1) according to claim 1 or 2, characterized in that a) a position of the positioning and/or alignment element (42) in the direction of the longitudinal axis (53) of the transverse bore (27) and/or b) an alignment of the positioning and/or alignment element (42) about the longitudinal axis (53) of the transverse bore (27) are/is secured by at least one securing element (40), the securing element (40) preferably being a screw (41) which is parallel to the longitudinal axis (53) of the transverse bore (27) or radially to the longitudinal axis (53) of the transverse bore (27) extends. Piston-cylinder unit (1) according to one of the preceding claims, characterized in that the positioning and/or alignment element (42) and the piston movement sensor (28) rest against one another via contact surfaces (57, 58), which have a positive fit in the circumferential direction an alignment of the transverse bore (27) around the longitudinal axis (53). Restrict or specify piston movement sensor (28) relative to the positioning and / or alignment element (42). Piston-cylinder unit (1) according to one of the preceding claims, characterized in that the piston movement sensor (28) is held on the positioning and/or alignment element (42) via a latching connection or a permanent magnet (50, 60). Piston-cylinder unit (1) according to one of the preceding claims, characterized in that the piston movement sensor (28) has a disassembly driver (64) on the side facing away from the positioning and/or alignment element (42), which is equipped with a disassembly tool can be coupled in order to apply dismantling forces to the piston movement sensor (28) for dismantling the piston movement sensor (28) from the positioning and/or alignment element (42), the dismantling driver (64) preferably being the internal thread (62) of the piston movement sensor (28). is formed and in particular the internal thread (62) is formed by a thread insert (63) which is injected or pressed into a sensor housing (55) of the piston movement sensor (28). Piston-cylinder unit (1) according to one of the preceding claims, characterized in that the piston movement sensor (28) is connected to a housing plug (44) via a sensor cable (43), the sensor cable (43) preferably being detachably connected to the piston movement sensor ( 28) and/or the housing plug (44). Piston-cylinder unit (1) according to claim 7, characterized in that the housing plug (44) is detachably connected to the cylinder head (4). Piston-cylinder unit (1) according to claim 8, characterized in that the housing plug (44) has a flange (71) which is screwed to the cylinder head (4). Piston-cylinder unit (1) according to claim 9, characterized in that the flange (71) can be screwed to the cylinder head (4) in different orientations of the housing plug (44) around the longitudinal axis (53) of the transverse bore (27). Piston-cylinder unit (1) according to one of claims 7 to 10, characterized in that the housing plug (44) is L-shaped with two angled legs (67, 68), wherein a) a leg (68) in the transverse bore (27) of the cylinder head (4) and b) a leg (67) located on the outside of the cylinder head (4) extends. Piston-cylinder unit (1) according to one of the preceding claims, characterized in that the housing plug (44-I, 44-II) a) as a DIN plug or b) as a German plug is trained. Piston-cylinder unit (1) according to one of the preceding claims, characterized in that the transverse bore (27) is hydraulically separated from a pressure chamber (33) via a sealing element. Set with a) a piston-cylinder unit (1) according to one of claims 1 to 13 and b) two housing plugs (44-I, 44-II), which ba) are designed and intended for different purposes, bb) can optionally be inserted into the transverse bore (27) and bc) can be connected to the piston movement sensor (28) via one or the sensor cable (43). Group of piston-cylinder units (1) according to one of claims 1 to 13, wherein a) the group has two subgroups of piston-cylinder units (1) which are designed and intended for different purposes, a) has a first subgroup of piston-cylinder units (1) which have first housing plugs (44-I), b) has a second subgroup of piston-cylinder units (1) which have second housing plugs (44-II), c) the first housing plugs (44-I) and the second housing plugs (44-II) are designed and intended for different purposes and d) the piston-cylinder units (1) of the first subgroup and the piston-cylinder units (1) of the second subgroup have identical piston movement sensors (28).

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