Piston Cylinder Unit

Abstract

The present invention relates to a piston cylinder device 1. A piston motion sensor 28 is arranged in a horizontal hole 27 of a cylinder head 4 of the piston cylinder unit 1. According to the present invention, a positioning and / or alignment part 42 is supported on a bottom 47 in the horizontal hole 27, on which the piston motion sensor 28 is supported. The positioning and / or alignment part 42 predetermines an axial position of the piston motion sensor 28 in the horizontal hole 27. Furthermore, the positioning and / or alignment part 42 can predetermine an alignment of the piston motion sensor 28. The piston cylinder unit 1 of the present invention is used, for example, in a work machine, a construction machine, an agricultural machine, a marine machine, a wheel loader, an excavator, a dump truck, a crane, a forklift, or a lifting platform.

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 (especially a construction machine, an agricultural machine, a ship machine, a wheel loader, an excavator, a dump truck, a crane, a forklift, a lift, or other working machines known to be used in mechanical engineering). The piston cylinder unit can be used, for example, to move a part of a working machine (especially a tool, a locker, or other parts of the working machine) by an operator, support, slide, tilt, lift, lower, or move in other ways. Preferably, it is a hydraulic piston cylinder unit.

[0002] Furthermore, the present invention relates to a set including a piston cylinder unit, and this set can also be adopted in a working machine.

[0003] Finally, the present invention relates to a group of piston cylinder units, which has different subgroups, and the piston cylinder units of different subgroups are designed for different purposes. Such a group of piston cylinder units can be manufactured, provided, and sold by a manufacturer, for example, for various purposes, or can be provided and sold by a dealer, or can be stocked and / or used by a customer for various purposes.

Background Art

[0004] A general piston cylinder unit is known from Patent Document 1.

[0005] In the above-mentioned Patent Document 1, a known piston cylinder unit is shown in Figure 1. The dashed lines in Figure 1 indicate that the piston cylinder unit 1 can actually be formed to be longer, and that only a portion of the piston cylinder unit 1 is depicted. The piston cylinder unit 1 comprises a cylinder 2 with a cylinder tube 31, an internal space 3, and a cylinder head 4. The cylinder tube 31 is connected to the cylinder head 4 via a welded joint 23. A bearing bush 5 is located in the cylinder head 4.

[0006] Patent Document 1 deals with a hydraulic piston cylinder unit 1, which means that the internal space 3 is filled with hydraulic fluid 29, in particular oil. The cylinder 2 has connectors 6 and 24 for this purpose. Also in Patent Document 1, a hydraulic circuit, not shown, is connected to a hydraulic pump and a switching valve by connectors 6 and 24. Connectors 6 and 24 open to their respective assigned pressurized chambers 32 and 33. 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] Furthermore, in Patent Document 1, the operating force acting on the piston 7 is hydraulically generated in both directions along the longitudinal central axis 30 in response to the pressure generated by the hydraulic circuits of connectors 6 and 24, and the resulting adjustment movement of the piston 7 brings about a change in the volume of pressurized chambers 32 and 33. Figure 1 of Patent Document 1 shows the position where the piston 7 has moved completely to the right, i.e., the retracted position of the piston cylinder unit 1. The piston 7 is connected to the piston rod 8, and a piston rod eye 9 is located at the outer end of the piston rod 8. The piston rod eye 9 also has a bearing bush 10. The bearing bush 5 and bearing bush 10 serve to connect the piston cylinder unit 1 to the components of the working machine so that it can move relative to one another by the piston cylinder unit 1 and / or so that it can be subjected to force by the piston cylinder unit 1.

[0008] The piston rod 8 is supported by a 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. An additional O-ring 15, a wiper 16, and a slide bearing 17 are located at the other end of the guide bush 11. The piston 7 is fixed and rotatably mounted on the piston rod 8 and secured by a fixing nut 18. Furthermore, the piston 7 is fitted with an O-ring 19, a piston guide ring 20, a piston seal 21, and another piston guide ring 22. In this way, the piston 7 is supported in a sealed state together with the piston rod 8 and the piston rod eye 9 within the cylinder tube 31 of the cylinder 2 and moves back and forth.

[0009] Furthermore, in Patent Document 1, the sub-chamber 25 of the pressurizing chamber 33 of the cylinder head 4 is attached to the portion of the pressurizing chamber 33 whose boundary is defined by the cylinder tube 31. The sub-chamber 25 is also connected to a connector 24. An axially extending sensor signal channel 26 leads to this sub-chamber 25. The sensor signal channel 26 is also part of the pressurizing chamber 33 and is therefore filled with hydraulic fluid. The sensor signal channel 26 is connected to a lateral hole 27 that extends radially with respect to the longitudinal central axis 30 of the cylinder head 4. The lateral hole 27 extends to the outer surface of the cylinder head 4 and can be connected to the surrounding environment by a correction hole (not shown). The piston motion sensor 28 is located inside the lateral hole 27. The piston motion sensor 28 is used to detect the axial position of the piston 7 in the cylinder 2 by high-frequency technology. For this purpose, the piston motion sensor 28 emits a high-frequency signal that strikes the end face of the piston 7 or piston rod 8 via the sensor signal channel 26, sub-chamber 25, and pressurizing chamber 33, is reflected at this end, and then returns to the piston motion sensor 28. The path covered by the moving signal, particularly the termination side, can be identified from the reflected signal by evaluating high-frequency technology, especially 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 a seal, which axially seals the piston motion sensor 28 on both sides of the sensor signal channel 26, preventing hydraulic fluid from leaking from the pressurizing chamber 33 through the lateral hole 27. The piston motion sensor 28 has a connector plug 34 attached to the sensor housing of the piston motion sensor 28 and extending radially from the cylinder head 4. For further details, please refer to Patent Document 1, which is the subject of this disclosure.

[0011] Furthermore, a further development of the piston cylinder unit 1 described in Patent Document 1 is known from Patent Document 2. Patent Document 2 proposes placing a collimator or dielectric lens in the beam path of a high-frequency signal, which helps to improve the measurement accuracy of the piston motion sensor. A collimator is understood to be an optical device that generates a beam path such that a non-parallel beam generated from a source becomes a parallel beam. In a first radiation direction from the transmitting unit of the piston motion sensor to the end 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 parallel from the end of the piston or piston rod. The reflected high-frequency beam is then focused again by the collimator in the opposite second radiation direction 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 high-frequency beams that originally travel parallel to each other, or high-frequency beams that travel parallel to the longitudinal axis of the piston, or almost all beams, onto the piston motion sensor. Therefore, high-frequency beams that do not originate from, or at least do not originate directly from, the piston bottom surface at the end can be filtered out. Such unwanted beams are actually due to the fact that the collimator's refraction is not ideal, the beam is radiated and received as an ideal point, and the piston bottom surface is not ideally flat.

[0012] Furthermore, in the above-mentioned Patent Document 2, the use of a collimator is intended to improve the signal-to-noise ratio. The collimator may have a dielectric lens. It is also possible to use multiple dielectric lenses or Fresnel zone plates. The dielectric lens has a convex lens surface and / or is composed of dielectric plastic or dielectric ceramic, polytetrafluoroethylene, polyethylene or polypropylene, or may contain these materials. The dielectric lens preferably has a dielectric constant greater than that of the 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 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 it can be structurally separated from the piston motion sensor itself and the sensor housing. The piston motion sensor can also be formed as a compact, built-in cartridge that includes both the sensor and the analytical electronics. The piston motion sensor is positioned inside the transverse hole such that the longest dimension of the piston motion sensor extends in the direction of the longitudinal axis in the transverse hole. The beam deflection unit can be positioned at the bottom of a sub-chamber away from the sensor signal channel to prevent tampering with the measurement results. The collimator can be positioned within the sensor signal channel. For further details, please refer to Patent Document 2, which is the subject of this disclosure. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] German Patent Application Publication No. 102019122121 Specification

[0015] [Patent Document 2] European Patent Application Publication No. 3957868 [Overview of the project] [Problems that the invention aims to solve]

[0016] The present invention is based on the problem of proposing a piston cylinder unit in which a piston motion sensor is incorporated into the cylinder head. This piston cylinder unit is improved in terms of manufacturing cost, and / or parts diversity, and / or placement and alignment of the piston motion sensor relative to the cylinder head, and / or labor for installation and / or removal, and / or variability in operating conditions and connection conditions to the work machine.

[0017] Furthermore, the present invention is based on the objective of proposing a set of piston cylinder units that can be used for a variety of applications.

[0018] Finally, the present invention is based on the problem of proposing a group of piston cylinder units with two subgroups designed for different applications, but still with a small number of component types. [Means for solving the problem]

[0019] The problems of the present invention are solved according to the present invention having the features of the independent patent claims. Further preferred configurations of the present invention can be obtained from the dependent patent claims.

[0020] The present invention proposes a piston-cylinder unit comprising a cylinder having a cylinder head, a piston that is axially movable within the cylinder and pressurized by a pressurized fluid through a pressurizing chamber, and a piston motion sensor. The piston motion sensor is located inside a transverse hole in the cylinder head having a longitudinal axis. In this respect, the piston-cylinder unit can also be formed according to various modifications of the prior art cited above.

[0021] Further embodiments of the present invention are based on the recognition that, in particular, for the required accuracy of the measurement results of a piston motion sensor located inside a horizontal bore, it is important that the piston motion sensor, and by extension the high-frequency radiation (or other sensor signal) transmitting and / or receiving unit, is located at both predetermined positions inside the horizontal bore that represent the axial position of the piston motion sensor along the longitudinal axis of the horizontal bore, and predetermined positions that represent the rotational position of the piston motion sensor about the longitudinal axis of the horizontal bore, and by extension the direction of radiation of the signal from the piston motion sensor.

[0022] In embodiments known from the prior art, manufacturing effort is increased on the one hand due to manufacturing tolerances, and on the other hand, the effort required to install the piston motion sensor into the lateral hole of the cylinder head is increased. Furthermore, piston motion sensors, especially sensor housings of different dimensions, may have to be manufactured for a series of piston-cylinder units of different dimensions (particularly different diameters of the cylinder tube, and therefore the dimensions of the cylinder head) according to the prior art. This is because the different dimensions of the piston-cylinder units result in different distances between the sensor signal channel in the cylinder head and the connector plug on the outer surface of the cylinder head, requiring different lengths for the sensor housings.

[0023] The present invention proposes the following improvements in the field of this tension. According to the present invention, it is proposed that a positioning and / or alignment part can be used. The positioning and / or alignment part ensures the correct alignment of the piston motion sensor in the axial length direction of the transverse hole. Thereby, the high-frequency signal of the piston motion sensor passes through the sensor signal channel, any collimator, and the pressure chamber at the correct position, and / or hits the end face of the piston or the piston rod at the correct position. Alternatively or additionally, the positioning and / or alignment part can also be used to pre-determine the position of the piston motion sensor. When the positioning and / or alignment part is additionally used for the positioning and alignment of the piston motion sensor, the deviation in the position and alignment of the high-frequency signal transmitted by the piston motion sensor is easily and surely ensured within a predetermined small tolerance range.

[0024] According to the present invention, the positioning and / or alignment part is arranged inside the transverse hole and is supported inside the transverse hole in the direction of the longitudinal axis in the transverse hole, that is, in the mounting direction. This support can be provided, for example, on the side surface, inclined surface, step, taper, or annular collar of the transverse hole. The positioning and / or alignment part takes an axial position defined inside the transverse hole, and this position can be pre-determined during the manufacture of the transverse hole, that is, during the manufacture of the side surface, inclined surface, step, taper, or annular collar.

[0025] The piston motion sensor is supported above the positioning and / or alignment part in the direction of the longitudinal axis. Since the positioning and / or alignment part takes an axial position defined inside the transverse hole, by supporting the piston motion sensor above the positioning and / or alignment part, it is ensured that the piston motion sensor also takes a defined position inside the transverse hole.

[0026] When the same piston motion sensor is used for piston cylinder units of different dimensions, the same piston motion sensor can be used for different piston cylinder units, and there is an advantage that a predetermined position of the piston motion sensor inside the lateral hole is adjusted by positioning and / or alignment portions of different lengths.

[0027] As described above, the support of the positioning and / or alignment portion can be reliably achieved by any side surface, inclined surface, step, taper, or annular collar of the lateral hole. In a particularly simple proposal of the present invention, the lateral hole can be formed as a non-through hole, and the positioning and / or alignment portion can be supported at the bottom of the non-through hole (particularly the edge region of the conical bottom). In this case, the position of the positioning and / or alignment portion, and thus the position of the piston motion sensor, can also be predetermined by the depth of the non-through hole.

[0028] It is also possible to predetermine the alignment of the positioning and / or alignment portion around the longitudinal axis of the lateral hole. This can be achieved, for example, by a form fit between the cross-section of the housing of the positioning and / or alignment portion and the lateral hole. For example, the lateral hole can extend in the direction of the longitudinal axis and have a groove or recess (or rib or protrusion) that fits in a form fit manner with a rib or protrusion (or groove or recess) of the housing of the positioning and / or alignment portion. However, the alignment of the positioning and / or alignment portion can also be ensured by having an eccentric recess (or protrusion) that engages with a corresponding protrusion (or recess) at the bottom on the end face of the housing of the positioning and / or alignment portion facing the bottom of the lateral hole.

[0029] A further aspect of the present invention aims to fix the positioning and / or alignment unit 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 unit inside the transverse hole. Thus, the fixing part serves to ensure that both the positioning and / or alignment unit and the piston motion sensor are in the predetermined position and continue to operate. Alternatively or cumulatively, it is also possible to use at least one fixing part to fix the alignment of the positioning and / or alignment unit around the longitudinal axis of the transverse hole (and thus fix the alignment of the piston motion sensor in certain situations).

[0030] The nature of the fixing part configuration can vary. For example, fixing bolts, fixing split pins, latch connections, tongue-and-groove connections for fixing alignment can be used. In a very simple embodiment, the fixing part is a screw. The screw can extend parallel to the longitudinal axis of the transverse hole. For example, the screw can penetrate the bottom of a non-through hole and pass through the hole from the opposite side. However, it is also possible for the screw forming the fixing part to extend 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, extends through the hole to the positioning and / or alignment part, where the screw is fixed to the female thread of the positioning and / or alignment part. Furthermore, the positioning and / or alignment part can have both a surface-side screw hole used when the screw extends parallel to the longitudinal axis of the transverse hole, and a radial screw hole for mounting when the screw extends radially with respect to the longitudinal axis of the transverse hole.

[0031] It is preferable that the positioning and / or alignment section and the piston motion sensor are in direct contact with each other via contact surfaces. These contact surfaces can ensure the correct positioning of the piston motion sensor in the direction of the longitudinal axis of the transverse hole.

[0032] Not only is it necessary to predetermine the axial position of the piston motion sensor inside the lateral bore, but it may also be necessary to predetermine the arrangement of the piston motion sensor with respect to the rotation angle around the longitudinal axis of the lateral bore. The rotation angle needs to be predetermined, for example, so that the sensor signal emitted from the piston motion sensor passes through the sensor signal channel and / or strikes the end face of the piston or piston rod at a predetermined point and / or arrangement. This arrangement can be predetermined, for example, by the piston motion sensor interacting with the lateral bore in a circumferential geometry fitting manner, where the arrangement is predetermined by geometry fitting on the one hand, and on the other hand, this predetermined arrangement is consequently maintained during operation. For example, the lateral bore may be provided with a groove extending in the direction of the longitudinal axis, or a recess into which a projection or rib of the piston motion sensor housing is positioned. Conversely, it is also possible to provide a rib extending in the axial longitudinal direction of the lateral bore, or a projection that engages with the groove or recess of the piston motion sensor housing. Furthermore, it is possible to have one lateral hole and the other piston motion sensor housing have corresponding non-circular, for example, elliptical cross-sections so that they fit together precisely in the correct alignment.

[0033] In the proposed invention, the contact surfaces of one positioning and / or alignment portion and the other piston motion sensor are connected to each other via a shape fit around the longitudinal axis of the transverse hole. This shape fit restricts and even pre-determines the relative alignment between one piston motion sensor and the other positioning and / or alignment portion (hereinafter referred to as the contact portion). There are various possibilities for this shape fit. To give some examples that are not limiting to the invention, one of the two contact portions may be provided with a projection that engages with a recess in the other contact portion. Alternatively, the end face of the contact portion may be provided with a step that interacts with a corresponding step in the other contact portion in a shape fit manner to ensure twist prevention and pre-determined alignment.

[0034] A further aspect of the present invention aims to enable the removal of the piston motion sensor. This can be done, for example, for maintenance purposes, in case of piston motion sensor failure, for cleaning purposes, or for the use of another piston motion sensor having a different measurement range or different measurement accuracy. In this case, the piston motion sensor is preferably held detachably from the positioning and / or alignment part, but a certain retaining force is still ensured by the connection. It is preferable that only a removal force exceeding the threshold of the retaining force of the connection should be applied to remove it.

[0035] In one configuration of the present invention, the piston motion sensor is connected to the positioning and / or alignment unit via a latch connection. In this case, the threshold of the holding force is predetermined by the latch force of the latch connection. If the installer applies a release force greater than the latch force to the piston motion sensor, the latch connection is released, the piston motion sensor is removed from the positioning and / or alignment unit, and removed from the side hole.

[0036] In another embodiment, a permanent magnet is used to generate a magnetic force as a holding force between the piston motion sensor and the positioning and / or alignment part. In this case, the threshold of the holding force is predetermined by the magnetic force required for release. Within the scope of the present invention, it is also possible to provide permanent magnets on both the piston motion sensor and the positioning and / or alignment part so that a magnetic force is generated between them.

[0037] The installer can apply the necessary removal force in any way for removal. In one proposal of the present invention, the piston motion sensor has a removal fastener in a face-side area away from the positioning and / or alignment portion. The removal fastener 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 fastener. For example, the removal fastener can be designed as a type of hook connection to which a counter-hook removal tool is hooked, the removal fastener and the removal tool can form a latch connection, or the removal fastener and the removal tool can be connected to each other via permanent magnets. In a particular proposal of the present invention, the removal fastener is a female thread of the piston motion sensor. A removal rod can then be screwed into this female thread, and the necessary removal force can be applied to the piston motion sensor via the removal rod protruding from the lateral hole after screwing.

[0038] The female thread can be formed from the solid material of the sensor housing. In one proposed version of the present invention, the female thread is formed by an insert portion having a female thread. This insert portion having a female thread is either embedded inside the sensor housing of the piston motion sensor or pressed into a hole in the sensor housing. The use of such an insert portion having a female thread is advantageous, for example, when the sensor housing is made of a material that does not provide the necessary strength for the manufacture of the female thread. In this case, a stronger material, particularly metal, can be selected as the material for the insert portion having a female thread. A stronger material can provide the strength necessary for a threaded connection in the threaded area. On the other hand, the insert portion having a female thread can have an enlarged outer surface, thereby enabling connection to the sensor housing over a large area and power transmission.

[0039] In principle, the connector plug can be directly formed by the sensor housing, or it can be held on the sensor housing and protrude outward from the lateral hole and cylinder head, where the connector plug can be connected to the required connecting cable. In one proposal of the present invention, the piston motion sensor is connected to the housing plug via a sensor cable. Thus, the sensor unit has two subunits, the piston motion sensor and the housing plug, which are flexibly connected to each other via the sensor cable. By connecting via a sensor cable, the sensor cable can be bent or stretched to some extent to accommodate different installation situations, making it easy to adjust for using the same piston motion sensor and the same housing plug on piston cylinder units of different dimensions. On the other hand, in certain situations, the sensor housing may be formed more rigidly or shorter so that it does not need to suspend and connect the entire radial area from the actual measurement area to the connecting plug, but rather a partial area can be suspended and connected by the sensor cable.

[0040] It is particularly preferable that the sensor cable is detachably connected to the piston motion sensor and / or housing plug. This allows, for example, to install only the piston motion sensor separately first, then connect the sensor cable, and finally install the housing plug, with corresponding removals also being possible separately. Furthermore, for example, in the event of maintenance or failure, only the piston motion sensor or housing plug may need to be replaced, while the rest of the piston motion sensor and housing plug may remain usable.

[0041] However, in certain proposals of the present invention, the detachable connection to the sensor cable allows the same piston motion sensor to be used with different housing plugs, enabling adaptation to different applications requiring different housing plugs.

[0042] It is also preferable that the housing plug is removably connected to the cylinder head. In one proposal of the present invention, the housing plug is provided with a flange for this purpose. The flange is screwable onto the cylinder head, allowing for a secure connection between the housing plug and the cylinder head.

[0043] The flange can be screwed into the cylinder head in a lateral hole with different alignment configurations of the housing plug relative to the center of the longitudinal axis, thereby taking into account various installation conditions.

[0044] Any different housing plug can be used within the scope of the present invention. On the other hand, the housing plug can have different shapes. The first housing plug is formed in a straight line, and 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 includes support portions having two angles. In this case, one support portion extends into the interior of the transverse hole of the cylinder head. In this case, the sensor cable can be connected to the end region of this support portion. In contrast, the other support portion extends to the outside of the cylinder head. This support portion can extend radially with respect to the longitudinal axis of the transverse hole. In the installation configuration, the support portion is oriented parallel to the longitudinal central axis of the cylinder of the piston cylinder unit, which is preferable in some applications. In this case, the end side of the latter support portion can be used to connect a connecting cable.

[0045] In the piston cylinder unit according to the present invention, in addition to using housing plugs of different shapes, the housing plugs may, alternatively or cumulatively, have different connection shapes and pin configurations.

[0046] a) For example, the first type of housing plug can be formed as a so-called DIN plug. For example, this is an M12DIN plug that can be formed with 5 pins. Such DIN plugs are described in standards DIN41524 (3-pin and 5-pin), DIN45322 (5-pin with 60° spacing), DIN45326 (8-pin), and DIN45329 (7-pin) (these standards have been superseded by EN 60130-9). Various subtypes with different configurations of connection pins can be used for this first type of housing plug.

[0047] aa) In the first subtype, the first pin is not assigned. The second pin is assigned to the VDC function (voltage supply for 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.

[0048] ab) In the second subtype of the first type, the first pin may be left unassigned, the second pin may be assigned to VDC, the third pin may be assigned to GND, the fourth pin may be assigned to the pulse width modulated signal, and the fifth pin may be left unassigned.

[0049] b) In the case of the second type of housing plug, the housing plug is formed as a so-called German plug (Deutsch-Stecker), for example, a 4-pin German plug DT04.

[0050] ba) For example, the first subtype of the second type can be equipped with a first pin to ensure the VDC function. The second pin can be assigned to the CAN LO function, the third pin to the GND function, and the fourth pin to the CAN HI function.

[0051] bb) In contrast, the second subtype of the second type allows the first pin to be assigned to the VDC function, the second pin to the GND function, the third pin to the PWM function, and the fourth pin to be left unassigned.

[0052] According to the present invention, depending on the requirements and intended application, the same piston motion sensor can be optionally combined with housing plugs of different shapes and angles of the housing plug support portion and / or the aforementioned different types and subtypes of housing plugs via a removable sensor cable.

[0053] In embodiments known from the prior art, the piston motion sensor is fluidically connected to the pressurizing chamber via a sensor signal channel, and the piston motion sensor itself is pressurized with hydraulic fluid. Therefore, the sensor housing of the piston motion sensor needed to be equipped with ring grooves on both sides of the sensor signal channel to seal the piston motion sensor within the lateral cavity. In these embodiments, when the piston motion sensor needs to be replaced, the hydraulic fluid must be drained, otherwise the hydraulic fluid will leak out of the lateral cavity of the removed piston motion sensor. One configuration of the piston cylinder unit of the present invention proposes fluidically separating the lateral cavity from the pressurizing chamber via a seal. In this case, the seal blocks the passage, so that the piston motion sensor can be removed from the lateral cavity without the hydraulic fluid leaking out. Here, the seal is preferably designed and made of a material that does not adversely affect the piston motion sensor as much as possible, so that the high-frequency radiated signal of the piston motion sensor can pass through.

[0054] In one particular proposal of the present invention, the sealing portion is configured as a collimator, in which case the collimator is multifunctional. This is because the collimator ensures a desired focusing method and parallel alignment of the beam, while also functioning as a sealing portion. Here, the collimator has at least one ring groove in the area of ​​its outer surface into which a sealing ring, particularly an O-ring, is inserted, and the sealing effect allows the collimator to interact with the sensor signal channel in which it is located.

[0055] A further solution to the problem underlying the present invention is represented by a set having the aforementioned piston cylinder unit. The set has at least two housing plugs. These two housing plugs are designed to be intended for different applications. Thus, for example, the two different housing plugs may be housing plugs of different shapes, types, and / or subtypes as described above.

[0056] Next, two housing plugs can be selectively inserted into the lateral holes, and the selected housing plug can be secured to the housing of the piston cylinder unit. Here, each selected housing plug is then connected to the piston motion sensor by a sensor cable. In this way, the customer is provided with a set that can connect the same piston motion sensor to different housing plugs in different installation situations, thereby expanding the range of applications and reducing the number of component types.

[0057] Further solutions to the problems underlying the present invention are provided by the aforementioned group of piston cylinder units, where the group comprises two distinct subgroups of piston cylinder units, each designed and intended for a different application. In the first subgroup, the piston cylinder unit has a first housing plug, while in the second subgroup, the piston cylinder unit has a second housing plug.

[0058] The first housing plug and the second housing plug are designed and intended for different applications, and the two subgroups of piston cylinder units 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, the piston cylinder units of the first subgroup and the piston cylinder units of the second subgroup have identically configured piston motion sensors. For example, such groups containing different subgroups may be offered by a manufacturer or distributor so that the 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 groups of piston cylinder units for different applications may also be kept in stock by an end customer, repair shop, or manufacturer of work machinery.

[0059] Preferred configurations of the present invention are evident from the claims, description, and drawings. The advantages of the features and combinations of features mentioned in the description are merely examples and may have alternative or cumulative effects that do not necessarily have to be achieved by embodiments of the present invention.

[0060] With regard to the original application documents and the disclosure (not the scope of protection) of the patent, the following is stated. Further features are derived from the drawings, in particular the illustrated shapes, the relative dimensions of some components to one another, and their relative arrangement and effective connection. Features of different embodiments of the invention, or combinations of features of different claims, are also possible and suggested hereby, deviating from the selected backreferences of the claims. This also applies to features shown in or described in separate drawings. These features can also be combined with features of different claims. Similarly, features described in the claims may be omitted for further embodiments of the invention, but this does not apply to the independent claims of the granted patent.

[0061] The features described in the claims and specification shall be understood with respect to their number, without requiring the explicit use of the adverb “at least,” so that there is exactly that number or more than the number described. Therefore, for example, when speaking of one element, this should be understood to mean that there is exactly one element, two elements, or more parts. The features described in the claims may be complemented by further features, or they may be the sole features of the subject matter of each claim.

[0062] The reference numerals included in the claims do not limit the scope of the subject matter protected by the claims. They are solely for the purpose of making the claims easier to understand. [Brief explanation of the drawing]

[0063] The present invention will be further described below with reference to preferred embodiments shown in the drawings. [Figure 1] This shows a longitudinal cross-section of a piston cylinder unit using conventional technology. [Figure 2] This is a longitudinal section of the piston-cylinder unit in the cylinder head region. [Figure 3] Figure 2 is a spatial exploded view showing the cylinder head along with the assigned structural components. [Figure 4] This is a spatial exploded view of the piston motion sensor and the positioning and / or alignment unit. [Figure 5] This is a spatial diagram showing a DIN plug (5-pin) type housing plug with a sensor cable. [Figure 6] Figure 5 is a side view of the housing plug with the sensor cable. [Figure 7] This is a spatial diagram showing a German plug (4-pin) type housing plug with a sensor cable. [Figure 8]Figure 7 is a side view showing the housing plug. [Modes for carrying out the invention]

[0064] Unless otherwise becomes apparent from the following text, the above description relating to the prior art and the embodiments of Figure 1 can be appropriately applied to embodiments of the present invention, and further disclosures in Patent Documents 1 and 2 can also be adopted within the framework of the present invention.

[0065] Figure 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 positioned in the sensor signal channel 26. The collimator 35 has a flat end face on the side facing the piston motion sensor 28, along a direction perpendicular to the longitudinal central axis 30. The collimator 35 is formed rotationally symmetric with respect to the longitudinal central axis 30. The collimator 35 has a curved, particularly parabolic, longitudinal cross-section, as shown in the figure. The collimator 35 has a ring groove 36, in which an O-ring 38 is positioned as a seal portion 37. The seal portion 37 ensures airtightness (sealing) of the hydraulic portion between the inner wall of the sensor signal channel 26 and the collimator 35. The sensor signal channel 26 also has a circumferential corner portion 39. When the pressurizing chamber 33 is pressurized by hydraulic pressure, 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 sealing portion 37 ensure that the lateral hole 27 is not pressurized by the hydraulic fluid, and therefore there is no need to take additional sealing measures 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.

[0066] As can be seen from the exploded view in Figure 3, a screw-shaped fixing part 40, a positioning and / or alignment part 42, a piston motion sensor 28, a sensor cable 43, and a housing plug 44 are attached to the side hole 27, and the housing plug 44 is fixed to the housing 46 of the cylinder head 4 via a fixing screw 45.

[0067] As shown in Figure 4, the positioning and / or alignment portion 42 is formed in a cylindrical shape with a diameter that allows it to be inserted into the horizontal hole 27 so that it fits just right. The lower surface of the positioning and / or alignment portion 42 is formed flat in the illustrated exemplary embodiment. The lower surface of the positioning and / or alignment portion 42 is in contact with the bottom 47 of the horizontal hole 27, which is formed here as a non-through hole.

[0068] The surface of the positioning and / or alignment section 42 facing the piston motion sensor 28 is basically flat, but a step 48 is formed thereon. This side of the positioning and / or alignment section 42 is provided with a cylindrical receiving section 49 that houses a permanent magnet 50, which can be bonded to or pressed into the receiving section 49. The outer surface of the permanent magnet 50 is positioned flush with a portion of the end face of the positioning and / or alignment section 42, away from the step 48.

[0069] On the side of the positioning and / or alignment section 42 away from the piston motion sensor 28, it has a female thread 51 positioned eccentrically with respect to the longitudinal axis 53 of the transverse hole. In the positioned position of the positioning and / or alignment section 42 installed within the transverse hole 27, the female thread 51 of the positioning and / or alignment section 42 opens into the transverse hole 27, and the thread 41 aligns with a hole 52 extending from the outside of the housing 46. In this way, the positioning and / or alignment section 42 is fixed in the correct position and positional relationship.

[0070] The positioning and / or alignment portion 42 also has a lateral hole 54, which may have an internal thread. As shown in Figure 2, if there is no hole 52 oriented parallel to the longitudinal axis 53 of the lateral hole, or if it is not used, and a hole oriented perpendicular to the drawing plane of Figure 2 is provided in the housing 46, then, as an alternative to fixing by screws 41, the positioning and / or alignment portion 42 can be fixed by screws that extend through the housing 46 perpendicular to the drawing plane of Figure 2 and are screwed into the inside of the lateral hole 54 of the positioning and / or alignment portion 42.

[0071] The piston motion sensor 28 has a sensor housing 55, which has a cylindrical shape and a diameter such that the sensor housing 55 fits just into the lateral hole 27. Compared to this shape, the sensor housing 5 Section 5 has a recess, in which the electronic unit and the high-frequency signal transmission and / or reception unit are located.

[0072] On the side of the sensor housing 55 facing the positioning and / or alignment portion 42, there is a step 56, which is formed in correspondence with the step 48 of the positioning and / or alignment portion 42. At positions away from the steps 48 and 56, the positioning and / or alignment portion 42 and the sensor housing 55 form contact surfaces 57 and 58, which are arranged laterally with respect to the longitudinal axis 53 and are in contact with each other, thereby predetermining the axial position of the piston motion sensor 28.

[0073] In contrast, the steps 48 and 56 form a shape-fitting portion with respect to the rotational direction about the longitudinal axis 53, thereby pre-determining the position of the piston motion sensor 28. In the relative positional relationship predetermined by the steps 48 and 56, a corresponding receiving portion 59 equipped with a permanent magnet 60 is provided in the sensor housing 55 alongside the receiving portion 49 and permanent magnet 50 of the positioning and / or alignment portion 42. The permanent magnet 60 is also fixed to the receiving portion 59, for example, by adhesive or press-fitting. The magnetic force between the permanent magnets 50 and 60 fixes the contact, and consequently the position and positional relationship, between the positioning and / or alignment portion 42 and the piston motion sensor 28.

[0074] On the side of the sensor housing 55 away from the positioning and / or alignment portion 42, there is a flat end face 61. In the region of this end face 61, the piston motion sensor 28 has a female thread 62 formed here by a threaded insert 63 injected into the sensor housing 55. The female thread 62 forms a removal fastener 64.

[0075] Furthermore, the end face 61 is provided with a plug receptacle 65 into which the plug 66 of the sensor cable 43 can be inserted. The plug 66 and plug receptacle 65 are preferably of the 5-pin Pico-Clasp connection (registered trademark). Figures 5 and 6 show the housing plug 44-I, where "I" indicates that it is a first type housing plug (see the description of the first type above).

[0076] As can be seen in Figure 6, the housing plug 44-I is formed in an L-shape, with support parts 67 and 68 bent at a 90-degree angle. A plug receptacle is provided at the end of the support part 68, into which the sensor cable plug 69 of the sensor cable 43 can be inserted. It is preferable that both the plug receptacle and the sensor cable plug 69 are of the "Pico-Clasp" type.

[0077] The outer end region of the support portion 68 extends coaxially with the longitudinal axis 53 of the transverse hole. The outer end region of the support portion 68 may be provided with an annular bead 70 or a sealing portion. When inserted into the transverse hole 27, the annular bead 70 frictionally engages with the support portion 68 within the transverse hole 27 and is elastically prestressed and fixed in place. Furthermore, a sealing material may also be provided here.

[0078] In the outlet region of the support portion 68 from the housing 46 of the cylinder head 4, the support portion 68 has a circumferential flange 71. The flange 71 is housed in a corresponding receiving portion or recess within the housing 46. The flange 71 has through holes oriented parallel to the longitudinal axis 53, through which the flange 71 can be screwed into corresponding threaded holes within the housing 46. Preferably, the flange 71 is provided with multiple through holes and threaded holes 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.

[0079] The end region of the support portion 67 forms a connector plug 34 that enables the connection of a connector cable. In the case of housing plug 44-I, the connector plug 34 has five pins 72, as shown in particular in Figure 5. In particular, this is a "DIN connector plug M12 5-pin" type connector plug 34. Here, the first type of housing plug 44-I can be formed according to the subtypes described above.

[0080] Figures 7 and 8 show housing plug 44-II, where "II" indicates a second type of housing plug. Here, the second type of housing plug 44-II can be formed according to the subtypes described above.

[0081] Each housing plug 44 incorporates an electronic configuration to modify the signal transmitted from the sensor cable plug 69 to the connector plug 34. The piston motion sensor 28 directly measures the stroke of the piston 7 or piston rod 8 within the piston cylinder unit 1. The piston motion sensor 28 is preferably based on a non-contact measuring radar system, in which the propagation time of the reflected signal returned to the transmitting unit, the end face of the piston 7 or piston rod 8, and the receiving unit is analyzed. The position and / or velocity can then be detected from the propagation time with high accuracy and robustness.

[0082] The piston cylinder unit 1 is preferably formed with a piston motion sensor 28 conforming to the IP69K protection rating. 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 achieved.

[0083] Furthermore, 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 will not be deformed, stressed, or damaged by high hydraulic pressures that can range from 100 bar to 600 bar.

[0084] The Pico Clasp plug, used to connect the sensor cable 43 and the piston motion sensor 28 to the housing plug 44, can have five pins to which GND, VDC, CAN LO, CAN HI, and an analog signal can be assigned. 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, a voltage or current proportional to the measurement signal can be transmitted as an analog signal.

[0085] Depending on the situation, the piston motion sensor 28 can measure, transmit, and / or analyze not only the stroke and / or velocity of the piston 7 or piston rod 8, but also other measurement variables (such as temperature). Furthermore, the temperature can be used for temperature compensation.

[0086] Furthermore, bidirectional transmission is possible via the housing plug 44, which allows for software updates of the piston motion sensor 28 and enables the execution of update functions. When 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%, and when the piston 7 is fully extended, the duty cycle is 95%. [Explanation of symbols]

[0087] 1 Piston Cylinder Unit 2 liters 3. Interior space 4 Cylinder head 5 Bearing bush 6 connectors 7 pistons 8 Piston rods 9 Piston rod eye 10 Bearing Bushings 11 Guide bush 12 Rod seals 13 O-rings 14 Support Rings 15 O-rings 16 Wipers 17 Slide bearings 18 Fixing nut 19 O-rings 20 Piston Guide Rings 21 Piston seal 22 Piston guide rings 23 Welded seams 24 connectors 25 Subchamber 26 Sensor signal channels 27 Horizontal cave 28 Piston motion sensor 29 Hydraulic fluid 30 (Cylinder) Longitudinal central axis 31 Cylinder tube 32 Pressurized chamber 33 Pressurized chamber 34 Connector Plug 35 Collimator 36 Ring grooves 37 Seal part 38 O-rings 39 Corner 40 Fixed part 41 screws 42 Positioning and / or alignment section 43 Sensor Cable 44 Housing Plug 45 Fixing screws 46 Housing 47 Bottom 48 steps 49 Receiving part 50 permanent magnets 51 Female thread 52 holes 53 (Longitudinal axis of the horizontal hole) 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 inserts 64 Removable fasteners 65 Plug receptacle 66 Sensor Cable Plug 67 Support part 68 Support part 69 Sensor Cable Plug 70 Ring Bead 71 Flange 72 pins

Claims

1. A cylinder having a cylinder head A piston that is movable in the axial direction inside the cylinder Equipped with a piston motion sensor The piston motion sensor is located in a lateral hole of the cylinder head having a longitudinal axis, The positioning and / or alignment portion is supported within the horizontal hole in the direction of the longitudinal axis of the horizontal hole, The piston motion sensor is characterized in that it is supported by a positioning and / or alignment portion in the direction of the longitudinal axis and is held on the positioning and / or alignment portion via a permanent magnet. The piston rod is supported by a guide bush so as to be movable axially along the longitudinal central axis. The guide bush is located on the opposite side of the cylinder head in the piston cylinder unit.

2. The piston cylinder unit according to claim 1, characterized in that the lateral hole is a non-through hole, and the positioning and / or alignment portion is supported at the bottom of the non-through hole.

3. 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 aforementioned horizontal hole is as follows: Secured by at least one fixing part, The piston cylinder unit according to claim 1, wherein the fixing portion is a screw that extends parallel to the longitudinal axis of the lateral hole or extends radially with respect to the longitudinal axis of the lateral hole.

4. The positioning and / or alignment unit and the piston motion sensor are in contact with each other via a contact surface. The piston cylinder unit according to claim 1, characterized in that the contact surface restricts or predetermines the alignment of the piston motion sensor with respect to the positioning and / or alignment portion via a circumferential shape fitting portion around the longitudinal axis of the lateral hole.

5. The piston motion sensor has a removal fastener on the side away from the positioning and / or alignment portion that can be connected 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 aforementioned removal fastener is formed as the female thread of the piston motion sensor, The piston cylinder unit according to claim 1, characterized in that the female thread is formed by an insert portion having a female thread that is injected or press-fitted into the sensor housing of the piston motion sensor.

6. The piston motion sensor is connected to the housing plug via a sensor cable. The piston cylinder unit according to claim 1, characterized in that the sensor cable is detachably connected to the piston motion sensor and / or the housing plug.

7. The piston cylinder unit according to claim 6, characterized in that the housing plug is detachably connected to the cylinder head.

8. The housing plug has a flange, The piston cylinder unit according to claim 7, characterized in that the flange is screwed to the cylinder head.

9. The piston cylinder unit according to claim 8, characterized in that the flange can be screwed to the cylinder head with respect to the center of the longitudinal axis of the lateral hole, with respect to different alignment arrangements of the housing plug.

10. The housing plug is formed in an L-shape including a support portion having two angles, One of the support portions having the aforementioned angle extends inward into the lateral hole of the cylinder head, The piston cylinder unit according to claim 6, characterized in that the other support portion having the aforementioned angle extends outward from the cylinder head.

11. The piston cylinder unit according to claim 6, characterized in that the housing plug is formed as a DIN plug or a German plug.

12. The piston cylinder unit according to claim 1, characterized in that the lateral hole is fluidly separated from the pressurizing chamber via a sealing portion.

13. A set comprising the piston cylinder unit according to claim 1 and two housing plugs, The two housing plugs are designed for different applications, are selectively insertable into the lateral holes, and can be connected to the piston motion sensor via a sensor cable, as a set.

14. A group comprising the piston cylinder unit described in claim 1, It has two subgroups of piston cylinder units designed for different applications, The first subgroup has a piston cylinder unit having a first housing plug, The second subgroup has a piston cylinder unit with a second housing plug, The first housing plug and the second housing plug are designed for different purposes. The piston cylinder units of the first subgroup and the piston cylinder units of the second subgroup are groups having the same piston motion sensor structure.

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