Piston Cylinder Unit

Abstract

The present invention relates to a piston cylinder device 1. The piston cylinder unit 1 has a piston motion sensor 28 arranged in a transverse bore 27 of a cylinder head 4 having a longitudinal axis 53. According to the present invention, the piston motion sensor 28 is detachably connected to a housing plug 44 via a sensor cable 43. The housing plug 44 is L-shaped. One support part of the housing plug 44 extends into the transverse bore 27 of the cylinder head 4, and the other support part extends lyingly outward from the cylinder head 4. The present invention allows the operation of piston cylinder units 1 with different types of housing plugs 44. The piston cylinder unit 1 of the present invention is used, for example, in working machines, construction machines, agricultural machines, marine machines, wheel loaders, excavators, dump trucks, cranes, forklifts or lifting platforms.

Description

[Technical field]

[0001] The present invention relates to a piston cylinder unit. In particular, the present invention relates to a piston cylinder unit that can be used in a working machine, in particular in a construction machine, an agricultural machine, a marine machine, a wheel loader, an excavator, a dump truck, a crane, a forklift, a lift platform or other working machines known to be used in mechanical engineering. The piston cylinder unit serves, for example, to manipulate, support, extend, tilt, lift, process or otherwise move parts of the working machine, in particular tools, rockers or other parts of the working machine. Preferably, it is a hydraulic piston cylinder unit.

[0002] Furthermore, the present invention relates to a set comprising a piston-cylinder unit, which set can also be employed in a work machine.

[0003] Finally, the invention relates to a group of piston-cylinder units, which group has different subgroups, the piston-cylinder units of which are designed for different applications, such a group of piston-cylinder units can for example be manufactured, provided and sold by a manufacturer for different applications, or provided and sold by a distributor, or stocked and / or used by a customer for different applications. [Background technology]

[0004] A typical piston-cylinder unit is known from US Pat. No. 5,399,633.

[0005] A known piston-cylinder unit from the above-mentioned patent document is shown in Fig. 1. The dashed lines in Fig. 1 make it clear that the piston-cylinder unit 1 can in fact be made longer and that only a part of the piston-cylinder unit 1 is depicted. The piston-cylinder unit 1 comprises a cylinder 2 with a cylinder tube 31, an interior space 3 and a cylinder head 4. The cylinder tube 31 is connected to the cylinder head 4 via a welded seam 23. A bearing bush 5 is arranged in the cylinder head 4.

[0006] The patent document 1 deals with a hydraulic piston-cylinder unit 1, which means that the internal space 3 is filled with a hydraulic fluid 29, in particular oil. For this purpose, the cylinder 2 has a connector 6 and a connector 24. In the patent document 1, a hydraulic circuit, not shown, is connected to a hydraulic pump and a switching valve by the connector 6 and the connector 24. The connectors 6 and the connector 24 open to the assigned pressurized chambers 32 and 33, respectively. The pressurized chambers 32 and 33 are formed in the internal space 3 and are separated from each other by a piston 7. The piston 7 is movable along the longitudinal central axis 30 of the cylinder 2, with the pressurized chambers 32 and 33 sealed.

[0007] In the above-mentioned patent document 1, the actuating force acting on the piston 7 is hydraulically generated in both directions along the longitudinal central axis 30 according to the pressure generated by the hydraulic circuit of the connector 6 and the connector 24, and the resulting adjustment movement of the piston 7 results in a change in the volume of the pressurizing chamber 32 and the pressurizing chamber 33. FIG. 1 of the above-mentioned patent document 1 shows the position in which the piston 7 has been moved completely to the right, i.e., 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 bush 5 and the bearing bush 10 serve to connect the piston-cylinder unit 1 to parts of the working machine for movement relative to each other by the piston-cylinder unit 1 and / or for forces being applied by the piston-cylinder unit 1.

[0008] The piston rod 8 is supported by the guide bush 11 so as to be movable axially along the longitudinal central axis 30. A rod seal 12, an O-ring 13 and a support ring 14 are provided for bearing and sealing. At the other end of the guide bush 11, an additional O-ring 15, a wiper 16 and a slide bearing 17 are arranged. The piston 7 is arranged rotatably and fixedly on the piston rod 8 and fixed by a fixing nut 18. Furthermore, an O-ring 19, a piston guide ring 20, a piston seal 21 and another piston guide ring 22 are arranged on the piston 7. In this way, the piston 7 is supported in a sealed manner together with the piston rod 8 and the piston rod eye 9 in the cylinder tube 31 of the cylinder 2 and moves back and forth.

[0009] Also, in the above-mentioned Patent Document 1, the subchamber 25 of the pressurized chamber 33 of the cylinder head 4 is attached to a part of the pressurized chamber 33 bounded by the cylinder tube 31. The subchamber 25 is also connected to the connector 24. An axially extending sensor signal channel 26 leads to this subchamber 25. The sensor signal channel 26 is also part of the pressurized chamber 33 and is therefore filled with hydraulic fluid. The sensor signal channel 26 is connected to a transverse hole 27 extending radially with respect to the longitudinal central axis 30 of the cylinder head 4. The transverse hole 27 extends to the outer surface of the cylinder head 4 and can be connected to the surrounding environment by a compensation hole, not shown. The piston motion sensor 28 is arranged inside the transverse hole 27. The piston motion sensor 28 is used to detect the axial position of the piston 7 in the cylinder 2 by means of high-frequency technology. For this purpose, the piston motion sensor 28 emits a high-frequency signal that hits the end face of the piston 7 or the piston rod 8 through the sensor signal channel 26, the subchamber 25 and the pressurized chamber 33, is reflected at this end side and returns to the piston motion sensor 28. The path covered by a traveling signal, and in particular the terminating side, can be ascertained from the reflected signal by evaluating high frequency techniques, in particular the travel time.

[0010] In the exemplary embodiment shown in Figure 1, the piston motion sensor 28 is pressurized with hydraulic fluid. The sensor housing of the piston motion sensor 28 has seals that axially seal the piston motion sensor 28 on both sides of the sensor signal channel 26 to prevent hydraulic fluid from leaking from the pressurized chamber 33 through the side hole 27. The piston motion sensor 28 has a connector plug 34 that is attached to the sensor housing of the piston motion sensor 28 and extends radially from the cylinder head 4. For more details, see US Patent Publication 2007 / 0139994, which is the subject of this disclosure.

[0011] Further development of the piston cylinder unit 1 of the above-mentioned Patent Document 1 is known from Patent Document 2. In Patent Document 2, it is proposed to place a collimator or a dielectric lens in the beam path of the high-frequency signal, which helps to increase the measurement accuracy of the piston motion sensor. The collimator is understood to be an optical device that generates a beam path such that a beam generated non-parallel from a source becomes a parallel beam. In addition, in a first radiation direction from the transmitting unit of the piston motion sensor to the end side of the piston or piston rod, the collimator converts the non-parallel beam emitted by the piston motion sensor into a parallel beam, and these parallel beams are then reflected in parallel from the end side of the piston or piston rod. The reflected high-frequency beams are then focused again in the opposite second radiation direction by the collimator and received and analyzed by the receiving unit of the piston motion sensor. The collimator also functions as a kind of filter that focuses only or almost all of the high-frequency beams that originally travel parallel to each other or parallel to the longitudinal axis of the piston on the piston motion sensor. Thus, it is possible to filter out high frequency beams which do not originate, or at least do not originate directly, from the bottom surface of the piston at the end side, which in practice is due to the fact that the collimator refraction is not ideal, the beam is not emitted and received ideally in a point-like manner, and the bottom surface of the piston is not ideally flat.

[0012] Also, in the above-mentioned Patent Document 2, the use of the collimator is aimed at improving the signal-to-noise ratio. The collimator may have a dielectric lens. It is also possible to use a plurality of dielectric lenses or Fresnel zone plates. The dielectric lens may have a convex lens surface and / or may be made of or contain a dielectric plastic or dielectric ceramic, polytetrafluoroethylene, polyethylene or polypropylene. The dielectric lens preferably has a dielectric constant (permittivity) greater than that of air and the hydraulic fluid in the piston-cylinder unit. The dielectric constant is, for example, 20% to 50% greater than that of the hydraulic fluid in the piston-cylinder unit. The difference in the dielectric constant and the curvature of the dielectric lens are consistent with each other. The dielectric lens may have a plano-convex lens shape. The convex surface of the lens may face the piston.

[0013] In contrast, the planar side faces the piston motion sensor. The collimator can be formed by the sensor housing or can be structurally separate from the piston motion sensor itself and the sensor housing. The piston motion sensor can be formed as a compact self-contained cartridge containing both the sensor and the analysis electronics. The piston motion sensor is disposed inside the side hole such that the longest dimension of the piston motion sensor extends in the direction of the longitudinal axis of the side hole. The beam deflector can be disposed at the bottom of the subchamber away from the sensor signal channel to prevent falsification of the measurement results. The collimator can be disposed in the sensor signal channel. For more details, see US Pat. No. 6,233,339, which is the subject of this disclosure. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] DE 102019122121 A1

[0015] [Patent Document 2] European Patent Application Publication No. 3957868 Summary of the Invention [Problem to be solved by the invention]

[0016] The invention is based on the task of proposing a piston-cylinder unit with a piston motion sensor integrated in the cylinder head, which is improved with regard to the manufacturing costs and / or the variety of parts and / or the arrangement and alignment of the piston motion sensor relative to the cylinder head and / or the effort of installation and / or removal and / or the variability of the conditions of use and of the connection to the working machine.

[0017] Furthermore, the object of the invention is to propose a set including a piston-cylinder unit, which is suitable for using the piston-cylinder unit for various purposes.

[0018] Finally, the invention is based on the task of proposing a group of piston-cylinder units, in which two subgroups are designed and intended for different applications, but which nevertheless have a small variety of components. [Means for solving the problem]

[0019] The object of the present invention is achieved according to the invention with the features of the independent patent claims. Further preferred configurations according to the invention can be taken from the dependent patent claims.

[0020] The invention proposes a piston-cylinder unit comprising a cylinder having a cylinder head, a piston axially movable in the cylinder and pressurized with a pressurized fluid via a pressure chamber, and a piston motion sensor arranged inside a lateral bore of the cylinder head having a longitudinal axis. In this respect, the piston-cylinder unit can also be formed according to various variants of the prior art cited above.

[0021] The invention is based in particular on the recognition that according to the prior art (see also the prior art mentioned at the outset), the piston motion sensor has a housing which extends to the side of the piston-cylinder unit and extends outward from there. In the housing of the piston motion sensor, a plug is held in an end area which is freely accessible from the outside and which extends radially outward from the cylinder head relative to the central longitudinal axis of the cylinder. In contrast, according to the invention, the piston motion sensor is connected to the housing plug via a sensor cable.

[0022] The sensor unit has two sub-units, the piston motion sensor and the housing plug, which are flexibly connected to each other via a sensor cable. The connection via the sensor cable allows easy adaptation to use the same piston motion sensor and the same housing plug for piston-cylinder units of different dimensions and allows the sensor cable to be slightly bent or stretched for different installation situations. On the other hand, in certain situations the sensor housing can be designed to be less rigid or shorter, since it is not necessary to connect the entire radial area from the actual measuring area to the connection plug in a suspended manner, but rather a partial area can be connected in a suspended manner with the sensor cable.

[0023] It is particularly preferred if the sensor cable is removably connected to the piston motion sensor and / or the housing plug, which makes it possible, for example, to first install only the piston motion sensor separately, then connect the sensor cable and finally install the housing plug, with the corresponding removal also being performed separately. Furthermore, for example, for maintenance purposes or in the case of a breakdown, only the piston motion sensor or the housing plug has to be replaced, while the remaining parts of the piston motion sensor and the housing plug can still potentially be used.

[0024] However, in a particular proposal of the present invention, the releasable connection to the sensor cable also makes it possible for the same piston motion sensor to be used with different housing plugs in order to allow adaptation to different applications requiring different housing plugs.

[0025] Any different housing plugs can be used within the scope of the present invention. On the one hand, the housing plugs can have different shapes. The first housing plug is formed in a straight line, while the second housing plug usable within the scope of the present invention can be designed in an L-shape. In this case, the housing plug comprises a support having two angles. In this case, one support extends inside the transverse bore of the cylinder head. In this case, the sensor cable can be connected to the end side area of ​​this support. In contrast, the other support extends outside the cylinder head. This support can extend radially with respect to the longitudinal axis of the transverse bore. In the installation situation, the support is oriented parallel to the longitudinal central axis of the cylinder of the piston-cylinder unit, which is preferred in some applications. In this case, the end side of the latter support can be used to connect the connection cable.

[0026] In particular, this embodiment is based on the realization that a plug, such as that used according to the above-mentioned US 2005 / 0133963 or the above-mentioned US 2005 / 0133963, which is aligned radially with respect to the longitudinal axis of the cylinder and fixed directly to the housing of the piston motion sensor, is disadvantageous when used in a machine tool, since the connecting cable connected to this plug usually does not extend radially with respect to the longitudinal axis of the cylinder, but rather, for example, is parallel to the longitudinal axis. This can lead to bending of the connecting cable immediately next to the plug, which can cause the connecting cable to be damaged. According to the prior art, in such a case, a plug receptacle is formed by attaching an adapter plug to the plug, which allows the connecting cable to be inserted in a direction parallel to the longitudinal axis of the cylinder.

[0027] However, the adapter plug is an unwanted additional component that must ensure a reliable contact even under the harsh operating conditions of the work tool. A reliable solution is provided by a housing plug with a support extending into the side hole and a connection of the sensor cable in the inner space of the side hole, which is isolated from the outside by the housing plug.

[0028] It is also preferred that the housing plug is removably connected to the cylinder head. In one proposal of the invention, the housing plug is provided with a flange for this purpose. The flange can be screwed into the cylinder head and allows a secure connection between the housing plug and the cylinder head.

[0029] The flange can be screwed into the cylinder head with different alignment arrangements of the housing plug in the transverse hole relative to the centre of the longitudinal axis, thereby taking into account the respective installation conditions.

[0030] In addition to using housing plugs of different shapes in the piston-cylinder unit according to the invention, the housing plugs can alternatively or cumulatively be provided with different connection shapes and pin configurations.

[0031] a) For example, it is possible for the housing plug of the first type to be designed as a so-called DIN plug. For example, this is an M12 DIN plug, which can be designed with 5 pins. Such DIN plugs are described in the standards DIN 41524 (3-pin and 5-pin), DIN 45322 (5 pins at 60° intervals), DIN 45326 (8 pins) and DIN 45329 (7 pins) (these standards have been replaced by EN 60130-9). Various subtypes of this housing plug of the first type are available which have different configurations of the contact pins.

[0032] aa) In the first subtype, the first pin is unassigned, the second pin is assigned to the VDC function (voltage supply of the piston motion sensor), the third pin is assigned to the GND (ground) function, the fourth pin is assigned to the CAN HI data bus and the fifth pin is assigned to the CAN LO data bus.

[0033] ab) In the second subtype of the first type, the first pin may be unassigned, the second pin may be assigned to VDC, the third pin may be assigned to GND, the fourth pin may be assigned to a pulse width modulated signal, and the fifth pin may be unassigned.

[0034] b) In the case of the second type of housing plug, the housing plug is made as a so-called German plug (Deutsch-Stecker), e.g. the 4-pin German plug DT04.

[0035] ba) For example, the first subtype of the second type may be equipped with a first pin that provides a VDC function, a second pin that is assigned to a CAN LO function, a third pin that is assigned to a GND function and a fourth pin that is assigned to a CAN HI function.

[0036] bb) In contrast, in a second subtype of the second type, it is possible for the first pin to be assigned to a VDC function, the second pin to be assigned to a GND function, the third pin to be assigned to a PWM function, and the fourth pin to be unassigned.

[0037] Further embodiments according to the invention are based in particular on the realization that for the required accuracy of the measurement results of a piston motion sensor arranged inside a lateral hole, it is important that the piston motion sensor, and thus the transmitting and / or receiving unit for high-frequency radiation (or other sensor signal), is arranged both at a defined position inside the lateral hole representing the axial position of the piston motion sensor along the longitudinal axis of the lateral hole and at a defined position representing the rotational position of the piston motion sensor around the longitudinal axis of the lateral hole and thus the radiation direction of the signal of the piston motion sensor.

[0038] The embodiments known from the prior art lead to increased production efforts on the one hand with regard to manufacturing tolerances and increased installation efforts of the piston motion sensor in the transverse bore of the cylinder head on the other hand. Also, the piston motion sensor, in particular the sensor housing of different dimensions, may have to be manufactured according to the prior art in a series of piston-cylinder units of different dimensions (in particular different diameters of the cylinder tube and thus dimensions of the cylinder head), because the different dimensions of the piston-cylinder units lead to different distances between the sensor signal channel in the cylinder head and the connector plug on the outer surface of the cylinder head, which requires different lengths of the sensor housing.

[0039] The invention proposes the following improvements in this field of tension: It is proposed according to the invention that a positioning and / or alignment part can be used, which ensures a correct alignment of the piston motion sensor in the axial longitudinal direction of the transverse bore.

[0040] Alternatively or additionally, the positioning and / or alignment unit can also be used to predetermine the position of the piston motion sensor. If the positioning and / or alignment unit is additionally used for positioning and alignment of the piston motion sensor, deviations in the position and alignment of the transmitted high-frequency signal of the piston motion sensor are simply and reliably guaranteed within a predefined small tolerance range.

[0041] According to the invention, the positioning and / or alignment feature is arranged inside the transverse hole and is supported therein in the direction of the longitudinal axis of the transverse hole, i.e. in the installation direction. This support can be provided, for example, on the side, inclined surface, step, taper or annular collar of the transverse hole. The positioning and / or alignment feature takes a defined axial position inside the transverse hole, which can be predetermined during the manufacture of the transverse hole, i.e. during the manufacture of the side, inclined surface, step, taper or annular collar.

[0042] The piston motion sensor is supported on top of the positioning and / or alignment part in the direction of the longitudinal axis. Since the positioning and / or alignment part has a defined axial position within the transverse bore, supporting the piston motion sensor on the positioning and / or alignment part ensures that the piston motion sensor also has a defined position within the transverse bore.

[0043] When using the same piston motion sensor for piston-cylinder units of different dimensions, the advantage is that the same piston motion sensor can be used for the different piston-cylinder units, but the predetermined position of the piston motion sensor inside the transverse bore is adjusted by positioning and / or alignment parts of different lengths.

[0044] As previously mentioned, the positioning and / or alignment support can be ensured by any side surface, bevel, step, taper, annular collar, or the like of the side hole.

[0045] In a particularly simple proposal of the invention, the cross hole can be formed as a blind hole and the positioning and / or alignment part can be supported at the bottom of the blind hole (in particular in the edge region of the conical bottom), in which case the position of the positioning and / or alignment part and thus also the position of the piston motion sensor can be predetermined by the depth of the blind hole.

[0046] It is also possible to predetermine the alignment of the positioning and / or alignment part around the longitudinal axis of the transverse hole. This can be achieved, for example, by a form-fit between a cross-section of the housing of the positioning and / or alignment part and the transverse hole. For example, the transverse hole has a groove or recess (or rib or protrusion) which extends in the direction of the longitudinal axis and fits in a form-fitting manner with a rib or protrusion (or groove or recess) of the housing of the positioning and / or alignment part. However, the alignment of the positioning and / or alignment part can also be ensured by having an eccentric recess (or protrusion) on the end face of the housing of the positioning and / or alignment part facing the bottom of the transverse hole, which engages with a corresponding protrusion (or recess) on the bottom.

[0047] A further aspect of the invention aims at fixing the positioning and / or alignment part inside the transverse hole. It is proposed to provide at least one fixing part. The fixing part serves to fix the longitudinal position of the positioning and / or alignment part inside the transverse hole. The fixing part therefore serves to ensure that both the positioning and / or alignment part and the piston motion sensor are in place and continue to operate.

[0048] Alternatively or cumulatively, it is also possible to use at least one fixing portion to fix the alignment of the positioning and / or alignment portion about the longitudinal axis of the transverse hole (and thus also the alignment of the piston motion sensor in certain circumstances).

[0049] The nature of the configuration of the fasteners can be varied. For example, a fastening bolt, a fastening split pin, a latch connection, a tongue and groove connection for fixing the alignment, etc. can be used. In a very simple embodiment, the fasteners are screws. The screws can run parallel to the longitudinal axis of the transverse hole. For example, the screws can penetrate the bottom of the blind hole and penetrate the hole from the other side.

[0050] However, it is also possible that the screw forming the fastening part extends radially with respect to the longitudinal axis of the transverse hole. In either case, the screw is accessible from the outside of the cylinder head and extends through the hole to the positioning and / or alignment part, where it is fixed into the female thread of the positioning and / or alignment part. Furthermore, the positioning and / or alignment part can have both a surface-side threaded hole, which is used when the screw extends parallel to the longitudinal axis of the transverse hole, and a radial threaded hole for mounting when the screw extends radially with respect to the longitudinal axis of the transverse hole.

[0051] The positioning and / or alignment part and the piston motion sensor are preferably in direct contact with each other via contact surfaces, which can ensure a correct positioning of the piston motion sensor in the direction of the longitudinal axis of the transverse bore.

[0052] Not only may the axial position of the piston motion sensor within the side bore need to be predetermined, but the placement of the piston motion sensor with respect to a rotation angle about the longitudinal axis of the side bore may also need to be predetermined, for example, such that a sensor signal emitted from the piston motion sensor passes through a sensor signal channel and / or impinges on an end face of the piston or piston rod at a predetermined point and / or in a predetermined placement.

[0053] This arrangement can be predetermined, for example, by the piston motion sensor interacting in a form-fitting manner in the circumferential direction with the transverse hole, on the one hand, the arrangement being predetermined by form-fitting, and on the other hand, the arrangement thus predetermined being consequently maintained during operation. For example, the transverse hole can be provided with a groove extending in the direction of the longitudinal axis or with a recess in which a protrusion or rib of the housing of the piston motion sensor is arranged.

[0054] Conversely, the cross hole has ribs extending in the axial longitudinal direction, or protrusions which engage in grooves or recesses in the housing of the piston motion sensor. It is also possible for one cross hole and the housing of the other piston motion sensor to have corresponding non-circular, for example elliptical, cross sections, so that they fit together exactly in the correct alignment.

[0055] In the present proposal, the contact surfaces of the positioning and / or alignment part on the one hand and the piston motion sensor on the other hand are connected to one another around the longitudinal axis of the transverse bore via a form fit, which limits and even predetermines the relative alignment of the positioning and / or alignment part on the one hand and the positioning and / or alignment part on the other hand (hereinafter referred to as contact part).

[0056] There are various possibilities for this form-fitting: to give some non-limiting examples, one of the two contacts can be provided with a protrusion that engages in a recess in the other contact, and the other end face of the contact can be provided with a step that interacts in a form-fitting manner with a corresponding step in the other contact, thereby ensuring predetermined anti-twisting and alignment.

[0057] A further aspect of the invention is aimed at making it possible to remove the piston motion sensor. This can be done, for example, for maintenance purposes, in case of a failure of the piston motion sensor, for cleaning purposes or for the use of another piston motion sensor with a different measuring range or a different measuring accuracy. In this case, the piston motion sensor is preferably held removably from the positioning and / or alignment part, but still with a constant holding force ensured by the connection. Also, in this case, it is preferably only necessary to apply a removal force that exceeds the holding force threshold of the connection in order to remove it.

[0058] In one configuration of the invention, the piston motion sensor is connected to the positioning and / or alignment feature via a latch connection, where the latching force of the latch connection predetermines the retention force threshold, and when an installer applies a removal force to the piston motion sensor that is greater than the latching force, the latch connection is released and the piston motion sensor is removed from the positioning and / or alignment feature and removed from the cross hole.

[0059] In another embodiment, a permanent magnet is used between the piston motion sensor and the positioning and / or alignment part to generate a magnetic force as the holding force. In this case, the threshold value of the holding force is predetermined by the magnetic force required for removal. Within the scope of the present invention, it is also possible that a permanent magnet is provided in each of the piston motion sensor and the positioning and / or alignment part, and a magnetic force is generated between them.

[0060] The installer can apply the necessary removal force for removal in any way. In one proposal of the invention, the piston motion sensor has a removal catch in the area of ​​the face side remote from the positioning and / or alignment part. The removal catch can be connected to a removal tool. The force required for removal can be applied to the piston motion sensor via the removal tool and the removal catch. For example, the removal catch can be designed as a kind of hook connection on which a counter hook removal tool is hooked, the removal catch and the removal tool can form a latch connection, or the removal catch and the removal tool can be connected to each other via a permanent magnet.

[0061] In a particular proposal of the invention, the removal fastener is an internal thread of the piston motion sensor, into which a removal rod can then be screwed and through which the removal rod protrudes from the transverse hole after screwing, the required removal force can be applied to the piston motion sensor.

[0062] The female thread can be formed from the solid material of the sensor housing. In one proposal of the invention, the female thread is formed by an insert part with a female thread. This insert part with a female thread is embedded inside the sensor housing of the piston motion sensor or pressed inside a bore of the sensor housing. The use of such an insert part with a female thread is advantageous, for example, if the sensor housing is made of a material that does not provide the necessary strength for the production of the female thread. In this case, a stronger material, in particular a metal, can be selected as the material of the insert part with a female thread. A stronger material can provide the necessary strength for the screw connection in the screwed area. On the other hand, the insert part with a female thread can have an enlarged outer surface, which allows a large-area connection to the sensor housing and power transmission.

[0063] In embodiments known from the prior art, the piston motion sensor was fluidly connected to the pressurized chamber via the sensor signal channel and the piston motion sensor itself was pressurized with hydraulic fluid. For this reason, the sensor housing of the piston motion sensor had to be equipped with ring grooves on both sides of the sensor signal channel in order to seal the piston motion sensor in the side bore. In these embodiments, if the piston motion sensor needs to be replaced, the hydraulic fluid has to be drained, since otherwise it would escape from the side bore of the removed piston motion sensor.

[0064] In one configuration of the piston-cylinder unit of the present invention, it is proposed to fluidically separate the side hole from the pressurizing chamber via a seal. In this case, the piston motion sensor can be removed from the side hole without hydraulic fluid flowing out of the side hole, since the seal blocks the passage. Here, it is preferable that the seal is designed and its material is selected so as not to adversely affect the piston motion sensor as much as possible, while allowing the high-frequency radiation signal of the piston motion sensor to pass through.

[0065] In one particular proposal of the invention, the seal is configured as a collimator, which is multifunctional since it ensures the desired focusing and parallel alignment of the beam and also serves as a seal. Here, the collimator has at least one ring groove in the area of ​​its outer surface into which a sealing ring, in particular an O-ring, is inserted, which by sealing effect is able to interact with the sensor signal channel in which the collimator is located.

[0066] A further solution to the problem underlying the present invention is represented by a set with the piston-cylinder unit described above. The set has at least two housing plugs. These two housing plugs are intended and designed for different applications. Thus, for example, the two different housing plugs may be housing plugs of different shapes, types and / or subtypes described above.

[0067] Two housing plugs can then be selectively inserted into the cross holes, and the selected housing plugs can be fixed to the housing of the piston-cylinder unit. Here, each selected housing plug is then connected to a piston motion sensor by a sensor cable. In this way, the customer is provided with a set in which the same piston motion sensor can be connected to different housing plugs in different installation situations, thereby expanding the range of applications and reducing the variety of components.

[0068] A further solution to the problem underlying the present invention is shown by the aforementioned group of piston-cylinder units, where the group has two different subgroups of piston-cylinder units, which are designed and intended for different applications: in the first subgroup the piston-cylinder units have a first housing plug, whereas in the second subgroup the piston-cylinder units have a second housing plug.

[0069] The first housing plug and the second housing plug are designed and intended for different applications and the piston-cylinder units of the two subgroups are designed and intended for different applications. The first housing plug and the second housing plug may differ from each other by the aforementioned shape, type and / or subtype. In this case, identically configured piston motion sensors are present in the piston-cylinder units of the first subgroup and in the piston-cylinder units of the second subgroup. For example, such a group with different subgroups can be offered by a manufacturer or a distributor, so that a customer can obtain either the piston-cylinder units of the first subgroup or the piston-cylinder units of the second subgroup depending on the application. However, such a group of piston-cylinder units for different applications can also be kept in stock by an end customer, a repair shop or a manufacturer of a working machine.

[0070] Preferred configurations of the invention are evident from the claims, the description and the drawings. The advantages of the features and combinations of features mentioned in the description are merely examples and may have alternative or cumulative effects, which advantages are not necessarily achieved by the embodiments according to the invention.

[0071] With regard to the disclosure (not the scope of protection) of the original application documents and the patent, the following is given: Further features result from the drawings, in particular from the illustrated shapes, the relative dimensions of the several components with respect to one another, and their relative arrangement and operative connection. Combinations of features of different embodiments of the invention or features of different claims are also possible and are suggested hereby, apart from selected backward references in the claims. This also applies to features shown in separate drawings or described in the description thereof. These features can also be combined with features of different claims. Similarly, features described in the claims can be omitted for further embodiments of the invention, but this does not apply to the independent claims of the granted patent.

[0072] Features described in the claims and the specification are to be understood in terms of the number, such that there is exactly this number or more than the number described, without the explicit use of the adverb "at least." Thus, for example, when speaking of one element, this should be understood to mean that there is exactly one element, two elements, or more. Features described in the claims may be supplemented by further features or may be the only features possessed by the subject matter of the respective claim.

[0073] Any reference signs included in the claims do not limit the scope of the subject matter protected by the claims, but are merely intended to facilitate understanding of the claims. [Brief description of the drawings]

[0074] The invention will now be further described with reference to preferred embodiments illustrated in the drawings. [Figure 1] 1 shows a longitudinal section of a piston-cylinder unit according to the prior art; [Diagram 2] 3 is a partial longitudinal section through a piston-cylinder unit in the region of the cylinder head. [Diagram 3] FIG. 3 is a spatially exploded view of the cylinder head of FIG. 2 with its assigned structural parts. [Figure 4] FIG. 13 is a spatially exploded view of the piston motion sensor and the positioning and / or alignment portion. [Diagram 5] FIG. 1 is a spatial view showing a housing plug of the DIN plug (5 pin) type equipped with a sensor cable. [Figure 6] FIG. 6 is a side view of the housing plug with the sensor cable of FIG. 5. [Figure 7] FIG. 1 is a spatial diagram showing a German plug (4 pin) type housing plug equipped with a sensor cable. [Figure 8]FIG. 8 is a side view of the housing plug of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0075] Unless anything different becomes evident from the following text, the above description regarding the prior art and the embodiment of FIG. 1 may be appropriately applied to the embodiments of the present invention, and the further disclosures of the above-mentioned Patent Document 1 and the above-mentioned Patent Document 2 may also be adopted within the framework of the present invention.

[0076] FIG. 2 shows the piston-cylinder unit 1 in the region of the cylinder head 4. The sensor signal channel 26 leads to the pressurized chamber 33 of the piston-cylinder unit 1. A collimator 35 is arranged in the sensor signal channel 26. On the side facing the piston motion sensor 28, the collimator 35 has a flat end face along a direction perpendicular to the longitudinal center axis 30. The collimator 35 is formed rotationally symmetrical with respect to the longitudinal center axis 30. The collimator 35 has, for example, a curved, in particular parabolic, longitudinal cross section as shown. The collimator 35 has an annular groove 36 in which an O-ring 38 is arranged as a seal 37. The seal 37 ensures the tightness (sealability) of the hydraulic part between the inner wall of the sensor signal channel 26 and the collimator 35. The sensor signal channel 26 also has a circumferential corner 39. When the pressurizing chamber 33 is hydraulically pressurized, pressure is generated by the hydraulic pressure acting on the spherical end face facing the piston 7, and the collimator 35 is pressed against the corner 39. This pressing of the collimator 35 against the corner 39 and / or the effect of the seal 37 ensure that the lateral hole 27 is not pressurized by hydraulic fluid, and therefore no additional sealing measures need to be taken for the lateral hole 27. On the other hand, this seal allows the piston motion sensor 28 to be removed without hydraulic fluid leaking from the lateral hole 27.

[0077] As can be seen from the exploded view of Figure 3, a fixing part 40 in the form of a screw 41, a positioning and / or alignment part 42, the piston motion sensor 28, a sensor cable 43 and a housing plug 44 are attached to the transverse hole 27, and the housing plug 44 is fixed to a housing 46 in the cylinder head 4 via a fixing screw 45.

[0078] 4, the positioning and / or alignment part 42 is formed in a cylindrical shape having a diameter that allows the positioning and / or alignment part 42 to be inserted so as to fit snugly into the transverse hole 27. The lower surface of the positioning and / or alignment part 42 is formed flat in the illustrated exemplary embodiment. The lower surface of the positioning and / or alignment part 42 contacts the bottom 47 of the transverse hole 27, which is formed here as a blind hole.

[0079] The surface of the positioning and / or alignment part 42 facing the piston motion sensor 28 is essentially flat, but is formed with a step 48. This surface of the positioning and / or alignment part 42 is provided with a cylindrical receiving part 49 in which a permanent magnet 50 is accommodated, which can be glued or pressed into the receiving part 49. The outer surface of the permanent magnet 50 is arranged flush with the partial surface of the end face of the positioning and / or alignment part 42 remote from the step 48.

[0080] The side of the positioning and / or alignment part 42 away from the piston motion sensor 28 has an internal thread 51 arranged eccentrically with respect to the longitudinal axis 53 of the transverse bore. In the positioned position of the positioning and / or alignment part 42 installed in the transverse bore 27, the internal thread 51 of the positioning and / or alignment part 42 opens into the transverse bore 27 and the thread 41 is aligned with a hole 52 extending from the outside of the housing 46. In this way, the positioning and / or alignment part 42 is fixed in the correct position and relative position.

[0081] The positioning and / or alignment part 42 also has a transverse hole 54, which may be provided with an internal thread. If the hole 52 oriented parallel to the longitudinal axis 53 of the transverse hole is not present or is not used, as shown in FIG. 2, and a hole oriented perpendicular to the drawing plane of FIG. 2 is provided in the housing 46, then, as an alternative to the fixing by the screw 41, the fixing of the positioning and / or alignment part 42 can be performed by a screw extending perpendicular to the drawing plane of FIG. 2 through the housing 46 and screwed inside the transverse hole 54 of the positioning and / or alignment part 42.

[0082] The piston motion sensor 28 has a sensor housing 55 which is cylindrical in outer shape and has a diameter such that the sensor housing 55 fits snugly into the cross hole 27. Compared to this outer shape, the sensor housing 55 has a recess in which area the electronic unit and the unit for transmitting and / or receiving high-frequency signals are arranged.

[0083] On the side of the sensor housing 55 facing the positioning and / or alignment part 42 there is a step 56, which is formed corresponding to the step 48 of the positioning and / or alignment part 42. At a position away from the step 48 and the step 56 the positioning and / or alignment part 42 and the sensor housing 55 form contact surfaces 57 and 58, which are arranged side by side transversely to the longitudinal axis 53 and abut each other, whereby the axial position of the piston motion sensor 28 is predetermined.

[0084] In contrast, the steps 48 and 56 form a form-fit with respect to the direction of rotation about the longitudinal axis 53, which predetermines the position of the piston motion sensor 28. In the relative position predetermined by the steps 48 and 56, a corresponding receiving portion 59 with a permanent magnet 60 is provided in the sensor housing 55 alongside the receiving portion 49 and the permanent magnet 50 of the positioning and / or alignment portion 42. The permanent magnet 60 is also fixed in the receiving portion 59, for example by gluing or press-fitting. The magnetic force between the permanent magnets 50 and 60 fixes the contact and thus the position and positional relationship between the positioning and / or alignment portion 42 and the piston motion sensor 28.

[0085] On the side of the sensor housing 55 facing away from the positioning and / or alignment part 42, the sensor housing 55 has a flat end face 61. In the region of this end face 61, the piston motion sensor 28 has an internal thread 62, here formed by a threaded insert 63 injection-molded into the sensor housing 55. The internal thread 62 forms a breakaway fastener 64.

[0086] Furthermore, the end face 61 is provided with a plug receptacle 65 into which a plug 66 of the sensor cable 43 can be plugged. The plug 66 and the plug receptacle 65 are preferably in the form of a 5-pin Pico-Clasp® connection. Figures 5 and 6 show the housing plug 44-I, where "I" indicates that this is a first type of housing plug (see above for the first type).

[0087] As can be seen from Fig. 6, the housing plug 44-I is formed in an L-shape, with support parts 67 and 68 bent at a 90 degree angle here. A plug receptacle is provided on the end side of the support part 68, into which a sensor cable plug 69 of the sensor cable 43 can be inserted. Both the plug receptacle and the sensor cable plug 69 are preferably of the "Pico-Clasp" type.

[0088] The outer end region of the support 68 extends coaxially with the longitudinal axis 53 of the transverse bore. The outer end region of the support 68 may be provided with an annular bead 70 or a seal. When inserted in the transverse bore 27, the annular bead 70 frictionally engages the support 68 in the transverse bore 27 and provides an elastic prestressed fixation. Furthermore, a seal can also be provided here.

[0089] In the area of ​​the exit of the support 68 from the housing 46 of the cylinder head 4, the support 68 has a flange 71, here circumferential. The flange 71 is received in a corresponding receiver or recess in the housing 46. The flange 71 has a through hole oriented parallel to the longitudinal axis 53, through which the flange 71 can be screwed into a corresponding threaded hole in the housing 46. Preferably, a number of through holes are provided in the flange 71 and a threaded hole is provided on the inside of the housing 46, so that the housing plug 44-I can be screwed into the housing 46 at different positions around the longitudinal axis 53.

[0090] The end region of the support 67 forms the connector plug 34, which allows the connection of a connector cable. In the case of the housing plug 44-I, the connector plug 34 has five pins 72, as shown in particular in Fig. 5. In particular, this is a connector plug 34 of the "DIN connector plug M12 5 pin" type. Here, the housing plug 44-I of the first type can be formed according to the subtypes described above.

[0091] 7 and 8 show a housing plug 44-II, where "II" indicates a second type of housing plug, which may be formed according to the subtypes described above.

[0092] The housing plug 44 incorporates an electronic arrangement for modifying the signal transmitted from the sensor cable plug 69 to the connector plug 34, respectively. The piston motion sensor 28 directly measures the stroke of the piston 7 or piston rod 8 in the piston-cylinder unit 1. The piston motion sensor 28 is preferably based on a non-contact measuring radar system, which analyses the travel time of the reflected signal back to the transmitting unit, the end face of the piston 7 or piston rod 8 and the receiving unit. From the travel time the position and / or velocity can then be determined with high precision and robustness.

[0093] The piston-cylinder unit 1 is formed with a piston motion sensor 28, preferably complying with the IP69K protection class. The piston motion sensor 28 can detect strokes 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, a resolution in the range of 0.2 mm to 4 mm, for example 0.5 mm to 2 mm or 0.8 mm to 1.5 mm, can be realized.

[0094] Further, an advantage of sealing the sensor signal channel 26 with a sealing portion or collimator 35 is that the piston motion sensor 28, the sensor housing 55, and the electronic configuration of the piston motion sensor 28 are not deformed, stressed, or damaged by high hydraulic pressures, which can be from 100 bar to 600 bar.

[0095] The sensor cable 43 and the Pico Clasp plug used to connect the piston motion sensor 28 to the housing plug 44 can have five pins and 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) and the measurement signal is transmitted via pulse width modulation. Alternatively, it is also possible to transmit a voltage or current proportional to the measurement signal as an analog signal.

[0096] In some circumstances, the piston motion sensor 28 can measure, transmit and / or analyze not only the stroke and / or speed of the piston 7 or piston rod 8 but also other measurement variables, such as temperature, which can be used for temperature compensation.

[0097] Also, bidirectional transmission is possible via the housing plug 44, which allows software updates of the piston motion sensor 28 to be performed and update functions to be performed. If a PWM signal is transmitted, its frequency is preferably 500 Hz. The duty cycle provides information about the measurement path of the piston 7. When the piston 7 is fully retracted, the duty cycle is for example 5%, when the piston 7 is fully extended, the duty cycle is 95%. [Explanation of symbols]

[0098] 1 Piston cylinder unit 2 Cylinder 3. Interior space 4. Cylinder head 5 Bearing bush 6 Connectors 7 Piston 8 Piston rod 9 Piston rod eye 10 Bearing bush 11 Guide bush 12 Rod seal 13 O-ring 14 Support Ring 15 O-ring 16 Wiper 17 Slide bearing 18 Fixing nut 19 O-ring 20 Piston guide ring 21 Piston seal 22 Piston guide ring 23 Welded seams 24 Connectors 25 Sub-chamber 26 Sensor Signal Channels 27 Side Cave 28 Piston Motion Sensor 29 Hydraulic Fluids 30 (cylinder) longitudinal center axis 31 Cylinder tube 32 Pressurized chamber 33 Pressurized chamber 34 Connector plug 35 Collimator 36 Ring groove 37 Seal part 38 O-ring 39 Corner 40 Fixed part 41 Screw 42 Positioning and / or alignment section 43 Sensor cable 44 Housing plug 45 Fixing screw 46 Housing 47 Bottom 48 Steps 49 Receiving part 50 Permanent Magnets 51 Female thread 52 holes 53 (of the side hole) longitudinal axis 54 Side Cave 55 Sensor housing 56 Steps 57 Contact surface 58 Contact surface 59 Receiving part 60 Permanent Magnets 61 End face 62 Female thread 63 Threaded Insert 64 Removal fastener 65 Plug receiving part 66 Sensor cable plug 67 Support part 68 Support part 69 Sensor cable plug 70 Annular Bead 71 Flange 72 pin

Claims

1. A cylinder having a cylinder head; a piston axially movable within the cylinder; Piston motion sensor and the piston motion sensor is disposed within a lateral bore in the cylinder head having a longitudinal axis; a positioning and / or alignment feature supported within the transverse hole in the direction of the longitudinal axis of the transverse hole; the piston motion sensor is connected to a housing plug via a sensor cable; the sensor cable is removably connected to the piston motion sensor and / or the housing plug; The housing plug is formed in an L-shape including two angled supports, The support portion having one angle extends to the inside of the transverse hole of the cylinder head, A piston-cylinder unit, characterized in that the support portion having another angle extends outside the cylinder head.

2. 2. The piston and cylinder unit according to claim 1, wherein the housing plug is detachably connected to the cylinder head.

3. 3. The piston and cylinder unit according to claim 2, wherein the housing plug has a flange which is screwed to the cylinder head.

4. 4. A piston and cylinder unit as claimed in claim 3, characterized in that the flange can be screwed into the cylinder head with different alignments of the housing plug about the longitudinal axis of the transverse bore.

5. 5. The piston-cylinder unit according to claim 1, wherein the housing plug is configured as a DIN plug or a German plug.

6. the positioning and / or alignment portion is supported within the transverse hole in the direction of the longitudinal axis of the transverse hole; A piston-cylinder unit according to any one of claims 1 to 5, characterised in that a piston motion sensor is supported on the positioning and / or alignment part in the direction of the longitudinal axis.

7. The lateral hole is a non-through hole, 7. The piston cylinder unit according to claim 6, characterized in that the positioning and / or alignment portion is supported on the bottom of the blind hole.

8. the position of the positioning and / or alignment portion in the direction of the longitudinal axis of the transverse hole, and / or the alignment of the positioning and / or alignment portion around the longitudinal axis in the transverse hole is fixed by at least one fixing portion; 8. A piston-cylinder unit as claimed in claim 6 or 7, characterized in that the fixing portion is preferably a screw extending parallel to the longitudinal axis of the transverse hole or extending radially with respect to the longitudinal axis of the transverse hole.

9. the positioning and / or alignment unit and the piston motion sensor are in contact with each other via a contact surface; 9. A piston-cylinder unit as claimed in claim 6, characterized in that the contact surface limits or predetermines the alignment of the piston motion sensor relative to the positioning and / or alignment portion via a circumferential form-fit about the longitudinal axis of the transverse hole.

10. 10. A piston cylinder unit according to claim 6, characterized in that the piston motion sensor is held on the positioning and / or alignment part via a latch connection or a permanent magnet.

11. the piston motion sensor has a removal fastener on a side remote from the positioning and / or alignment portion connectable to a removal tool for applying a removal force to the piston motion sensor to remove the piston motion sensor from the positioning and / or alignment portion; The removal fastener is preferably formed as an internal thread of the piston motion sensor; 11. A piston-cylinder unit according to claim 6, characterized in that the female thread is formed in particular by an insert member having a female thread which is injected or pressed into a sensor housing of the piston motion sensor.

12. The piston cylinder unit according to any one of claims 1 to 11, characterized in that the lateral hole is fluidically separated from the pressurizing chamber via a seal portion.

13. A set comprising a piston-cylinder unit according to any one of claims 1 to 12 and two housing plugs, The two housing plugs are designed for different uses and are selectively insertable into the side holes and connectable to the piston motion sensor via the sensor cable.

14. A group consisting of piston-cylinder units according to any one of claims 1 to 12, It has two subgroups of piston-cylinder units designed for different applications, The first subgroup includes the piston-cylinder unit having a first housing plug, A second subgroup includes the piston-cylinder unit having a second housing plug, the first housing plug and the second housing plug are designed for different purposes; A group, wherein the piston-cylinder units of the first subgroup and the piston-cylinder units of the second subgroup have the piston motion sensors of identical construction.

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