Locking unit with multi-directional Hall sensor and sensor unit

Abstract

Locking unit (2) comprising a housing (4) through which a longitudinal axis (L) extends, a piston (6) which is adjustable along the longitudinal axis (L) between a retracted position (S1) and an extended position (S2), wherein the locking unit (2) serves to lock the movement of the piston (6) which can be pressurized by a fluid, wherein the locking unit (2) has an electromagnet (8) and at least one detent element (10), wherein the piston (6) has at least one first detent receptacle (12) and a second detent receptacle (14) and the piston (6) can be fixed by the holding interaction of the at least one detent element (10) with one of the detent receptacles (12, 14), wherein a guide element (20) is rigidly connected to an armature (16) or an armature rod (18) of the electromagnet (8),which is adjustable along the longitudinal axis (L) between a locking position (P1) and a release position (P2) and, depending on the position (P1, P2), pushes the at least one detent element (10) radially outwards, characterized by a sensor unit formed from a permanent magnet (22), a multi-directional Hall sensor (24) for detecting a magnetic field of the permanent magnet (22) and a magnetic field modification means (26), wherein one of the permanent magnet (22) and multi-directional Hall sensor (24) is arranged fixedly with respect to the housing (4) and the other of the permanent magnet (22) and multi-directional Hall sensor (24) is adjustably connected to the guide element (20) along the longitudinal axis (L), wherein the piston (6) extends through a space (30) between the permanent magnet (22) and the multi-directional Hall sensor (24), wherein that area of ​​the piston (6),which is adjustable radially adjacent along the stationary element of permanent magnet (22) and multi-dimensional Hall sensor (24) through the space (30), defines a detection area (28), wherein the magnetic field changing means (26) is fixedly arranged on the piston (6) in the detection area (28), such that different magnetic permeabilities are formed in the detection area (28) along the longitudinal axis (L).

Description

[0001] The invention relates to a locking unit according to the preamble of claim 1 and a sensor unit according to claim 9.

[0002] Locking units are used, for example, for automatic transmissions of motor vehicles, which are locked when parked. Such locking units are typically designed so that the parking lock is in different states depending on the gear position, i.e., locked or unlocked. For this purpose, a piston can be used, for example, which can be moved hydraulically and locked electromechanically.

[0003] To detect the switching positions of a component, known locking units can each include a dedicated sensor. Therefore, each component to be detected requires at least one separate sensor.

[0004] It is therefore an object of the invention to provide an alternative or better design for a locking unit. Furthermore, a suitable general sensor unit is to be proposed. This is achieved according to the invention by a locking unit according to claim 1 and by a sensor unit according to claim 9. Embodiments are the subject of claims 2 to 8.

[0005] According to the invention, a locking unit is therefore proposed, comprising a housing through which a longitudinal axis passes, a piston which is adjustable along the longitudinal axis between a retracted position and an extended position, wherein the locking unit serves to lock the movement of the piston which can be subjected to pressure from a fluid, wherein the locking unit has an electromagnet and at least one locking element, wherein the piston has at least one first locking receptacle and a second locking receptacle and the piston can be fixed by the holding interaction of the at least one locking element with one of the locking receptacles, wherein a guide element is firmly connected to an armature or an armature rod of the electromagnet,which is adjustable along the longitudinal axis between a locking position and a release position and, depending on the position, pushes the at least one locking element radially outward. The locking unit according to the invention comprises a sensor unit formed from a permanent magnet, a multi-directional Hall sensor for detecting a magnetic field of the permanent magnet, and a magnetic field changing means. One of the permanent magnet and the multi-directional Hall sensor is arranged stationary with respect to the housing, and the other of the permanent magnet and the multi-directional Hall sensor is connected to the guide element so as to be adjustable along the longitudinal axis. The piston extends through a gap between the permanent magnet and the multi-directional Hall sensor. The region of the piston that is radially adjacent to the stationary element of the permanent magnet and the multi-directional Hall sensor and is adjustable through the gap defines a detection area.wherein the magnetic field changing means is fixedly arranged on the piston in the detection area, so that different magnetic permeabilities are formed along the longitudinal axis in the detection area.

[0006] The inventive concept lies in a position-dependent disturbance or change in strength of the magnetic field detected by a single sensor. The locking unit therefore has only a single sensor for determining the position of the piston and for determining the position of the guide element. The piston is a separate part from the guide element. The single sensor is the multi-directional Hall sensor. The advantage of the invention is that two components can be sensed independently of one another using one sensor or the multi-directional Hall sensor – a dual sensing effect. To achieve this, the invention utilizes the combined effect of two magnetic effects.

[0007] Firstly, the magnetic field of the permanent magnet acts on the multi-directional Hall sensor, which detects it and calculates a magnetic field incidence angle from it. The multi-directional Hall sensor has at least two Hall elements arranged at an angle to each other, preferably at right angles. The Hall elements therefore measure in different spatial directions and each generate a field curve, which is used to calculate the magnetic field incidence angle. All Hall elements of the multi-directional Hall sensor can be arranged in a single sensor housing. This allows for a cost-effective and space-saving design. The sensor housing can be a separate housing from the housing of the locking unit. This also allows for a cost-effective and space-saving design that can be manufactured separately and then mounted in the locking unit.The magnetic field angle of incidence provides information about the position of the permanent magnet relative to the multi-dimensional Hall sensor. This first effect (magnetic field angle of incidence) can be used to sense a first component, namely the position of the guide element. The permanent magnet can be arranged so that its magnetic field propagates in the radial direction, resulting in a favorable design with respect to the longitudinal axis and the adjustment direction of the piston.

[0008] On the other hand, the strength of the permanent magnet's magnetic field can be influenced by the magnetic field modifying means, for example, it can be weakened or amplified relative to another location in the detection range, whereby the multi-directional Hall sensor detects the correspondingly modified magnetic field. The magnetic field modifying means, which can be adjusted using the piston, can enter the permanent magnet's magnetic field and be arranged between the permanent magnet and the multi-directional Hall sensor, so that the detectable magnetic field is modified accordingly. The angle of incidence of the magnetic field used for the first effect may have no relevant influence on the magnetic field strength and thus the second effect, but the field strength of the magnetic field changes accordingly. This second effect (magnetic field strength) can be used to sense a second component, for example, the position of the piston.

[0009] By means of such a locking unit with a multi-directional Hall sensor, it is now not only possible to lock the piston selectively in one of its two positions (retracted position and extended position), but also to receive feedback in a very simple way as to whether locking by means of the guide element has actually taken place, since the position (locking position and release position) is also known.

[0010] The guide element is used in particular to push the locking elements radially outwards or not radially outwards, depending on its position. If the guide element is positioned accordingly, this achieves a locking mechanism. Due to an advantageous coupling of the permanent magnet with the guide element, the permanent magnet basically moves with the guide element. The permanent magnet and guide element are immobile relative to one another. The location of the guide element via the permanent magnet can therefore be sensed by the multi-directional Hall sensor. In particular, the angle of incidence of the magnetic field can be used to determine the location of the permanent magnet relative to the multi-directional Hall sensor, and the magnetic field strength can be used to determine whether the permanent magnet or the guide element is moving.whose magnetic field is changed by the magnetic field changing means, from which it can be determined in which location the magnetic field changing means or the piston is relative to the multi-space direction Hall sensor.

[0011] The multi-space direction Hall sensor can therefore, for example, determine the states “piston retracted” (retracted position) and “piston extended” (extended position) with respect to the piston and determine the states “locking elements locked” (locked position) and “locking elements released” (released position) with respect to the guide element.

[0012] The locking unit can be trained in a two-stage process. In a first training stage, only the first effect (magnetic field angle of incidence) is trained. In this case, the assigned value of the magnetic field angle of incidence is recorded in each position or relevant positions of the permanent magnet relative to the multi-directional Hall sensor. The position of the permanent magnet can then be deduced from the magnetic field angle of incidence. Advantageously, the magnetic field modification device does not yet change the magnetic field. In a second training stage, the second effect (magnetic field strength) is trained. In this case, the assigned value of the magnetic field strength is recorded in each position or relevant positions of the piston, and thus also of the magnetic field modification device. The position of the piston can then be deduced from the magnetic field strength.An evaluation unit can be trained to perform the evaluation during operation. The evaluation unit can be connected to the multi-directional Hall sensor for signal processing. It is conceivable that the training is temperature-dependent, since the component temperature or the temperature within the locking unit can influence the magnetic field strength of the permanent magnet. Therefore, training can take place at a defined reference temperature.

[0013] The magnetic field of the permanent magnet traverses the piston wall. The magnetic field modifying means serves to modify the magnetic field of the permanent magnet, for example, by attenuating or amplifying it. Attenuation can be achieved, for example, by measures with a magnetic insulation effect. Amplification, on the other hand, can be achieved, for example, by measures that increase the magnetic permeability of the piston wall to the traversing magnetic field.

[0014] The magnetic field changing means has a magnetic permeability that differs from another region or another location of the piston wall in the detection region, so that different magnetic permeabilities are formed in the detection region along the longitudinal axis L. The magnetic field changing means can be designed and / or arranged such that it itself has a magnetic permeability that differs from another location within the detection region that has a different magnetic permeability. Different magnetic permeabilities are then formed in the detection region along the longitudinal axis, which lead to different magnetic field strengths. The magnetic field changing means changes the magnetic field of the permanent magnet compared to a location in the detection region where no magnetic field changing means changes the magnetic field.

[0015] Advantageously, the magnetic permeability of the magnetic field-changing means is such that a detectably strong magnetic field can act on the multi-dimensional Hall sensor. This avoids "magnetic blind spots" where the sensor does not detect a magnetic field and thus cannot determine the location of the components and / or rule out a defect. Preferably, the magnetic permeability over the entire length of the detection range is such that a detectably strong magnetic field can act on the multi-dimensional Hall sensor. This allows the multi-dimensional Hall sensor to operate across the entire length of the detection range. This also avoids "magnetic blind spots."

[0016] The two boundaries in the longitudinal direction of the detection range can be defined by a straight line between the permanent magnet and the multi-directional Hall sensor at the respective end positions of the movable element of the two elements (permanent magnet and multi-directional Hall sensor) relative to the stationary element of the two elements. The boundaries can lie on these straight lines. This advantageously allows the detection range to be only as large as necessary to achieve the desired effect, but as small as possible to allow for design flexibility regarding other aspects that could potentially be negatively influenced by the detection range criteria.

[0017] The locking unit according to the invention significantly reduces manufacturing costs and design complexity, as it now requires only a single multi-directional Hall sensor to sense two independently moving components. It also reduces assembly effort and potential sources of error during assembly and operation.

[0018] The terms “radial” and “longitudinal direction” should be understood as referring to the longitudinal axis.

[0019] According to a conceivable development of the locking unit according to the invention, the permanent magnet or the multi-directional Hall sensor can be connected to the armature and / or the armature rod and / or the guide element via a connecting rod in a fixed manner. Such a connecting rod allows the distance between the permanent magnet or multi-directional Hall sensor and the electromagnet to be selected sufficiently large so that no significant influence on the magnetic field measurement is to be expected.

[0020] According to a conceivable development of the locking unit according to the invention, the permanent magnet or the multi-space direction Hall sensor can be arranged within the piston. This has the advantage for the permanent magnet that no wiring is required there. The piston can guide the permanent magnet or the multi-space direction Hall sensor radially, in particular via a floating bearing. This can be particularly advantageous in the design with a connecting rod, since in this case the connecting rod can define the distance between the permanent magnet or multi-space direction Hall sensor and the guide element, and thus the distance can be sufficiently large that the permanent magnet or multi-space direction Hall sensor can be arranged in a region of the piston spaced apart from the guide element.

[0021] According to a conceivable development of the locking unit according to the invention, a joint can be formed between the connecting rod, to which the permanent magnet can be firmly connected, and the armature rod or in the connecting rod. This allows a certain amount of play to be provided, which is defined by the joint, so that, for example, when the permanent magnet is guided by the piston, no overdetermination of the system occurs. Any tolerances can be easily compensated for by the joint without causing jamming or excessive wear. In combination with the optional radial guide on the piston, the joint also serves to prevent the permanent magnet from rubbing against the piston wall.The joint is particularly advantageous in the context of the dual sensing system according to the invention, because rubbing and / or jamming of the permanent magnet on the piston could not only lead to incorrect conclusions about the position of the permanent magnet, but the permanent magnet could then become permanently jammed to the piston, thus leading to incorrect conclusions about the position of the piston. The invention is specifically based on the fact that, on the one hand, the permanent magnet and, on the other hand, the piston can be freely adjusted relative to each other using the magnetic field-changing means.

[0022] According to a conceivable development of the locking unit according to the invention, the multi-directional Hall sensor can be mounted on the housing, preferably fixedly. This has the advantage that the multi-directional Hall sensor is easy to install and readily accessible for maintenance or replacement. Furthermore, this has the advantage that its cabling does not have to be routed deep into the housing, thus avoiding design complexity.

[0023] According to a conceivable development of the locking unit according to the invention, it can have an evaluation unit that can be coupled to the multi-directional Hall sensor and configured to determine a position of the guide element and the piston based on data from the multi-directional Hall sensor. This can advantageously be used, for example, to check whether a locking mechanism has actually functioned. For example, it can be checked whether a magnetic field angle of incidence and / or a magnetic field strength is above or below a threshold value.

[0024] According to a conceivable development of the locking unit according to the invention, it can have a preload spring which preloads the guide element into an end position. This end position can be the end position assumed by the guide element when the electromagnet is not energized. The end position can be the locking position of the guide element. In this way, the guide element can be reset in a simple manner when the electromagnet is de-energized. The preload of the preload spring can either act directly on the guide element, with the preload spring being supported against the guide element, or indirectly on the guide element, with the preload spring being supported against an intermediate component, which in turn is supported against the guide element or rests against it. The intermediate component can be an anchor rod part which is arranged on the anchor rod.

[0025] According to a further development of the locking unit according to the invention, the magnetic field modifying means can be formed integrally from a piston wall or formed in multiple pieces with a piston wall. The first case is advantageous because no separate component needs to be provided as a magnetic field modifying means. The magnetic field modifying means can, for example, be formed directly during manufacture of the piston, for example by thickening and / or thinning regions of the piston wall compared to a normal wall thickness of the piston. The second case is advantageous because here the same piston can be used for many different locking units (the identical part reduces manufacturing and logistics costs), which can be provided with a corresponding magnetic field modifying means depending on the application. The magnetic field modifying means can be manufactured separately from the piston and then firmly connected to it.

[0026] According to a further development of the locking unit according to the invention, the magnetic field changing means can comprise a single changing element, which either has a constant material thickness and / or constant magnetic permeability along the longitudinal axis and extends only in part of the detection area, or has an increasing material thickness and / or increasing magnetic permeability along the longitudinal axis, preferably continuously increasing. In the first case, the constant thickness serves to reliably detect a position or a position range, particularly in the case of a stepped transition from the changing element to an immediately adjacent area with a different magnetic permeability.The change element can be arranged in only part of the detection area, so that in the detection area immediately adjacent to the change element, an area or location with different magnetic permeability can be provided, since the change element is not arranged there. The length of the constant in the longitudinal direction can define a position or a position range, since the magnetic field of the permanent magnet is changed identically at each constant location. The first case represents incremental detection. In the second case, the increase serves as an intermediate resolution, since the magnetic field of the permanent magnet is changed accordingly with the increase. Intermediate positions can then also be detected, since here there is no incremental change, but rather a smooth change in the magnetic field of the permanent magnet.

[0027] According to a conceivable development of the locking unit according to the invention, the magnetic field modification means can extend longitudinally across the entire detection area with increasing material thickness and / or increasing magnetic permeability. This allows not only discrete positions to be sensed and evaluated in stages, but also allows a stroke-proportional displacement measurement to be performed through the continuous magnetic field and thus signal influence. This allows the resolution of the position measurement to increase. The resolution is then determined by the bit rate of the electronics, for example, the evaluation unit, and not by the geometry of the locking unit and its components.

[0028] According to a conceivable development of the locking unit according to the invention, the magnetic field-changing means can increase continuously with increasing material thickness and / or increasing magnetic permeability, for example, it can be designed as a wedge. This continuity serves to ensure a uniform change in the magnetic field strength, since a longitudinal adjustment of the armature correlates with the change in the magnetic field strength. This also enables reliable signal detection.

[0029] According to a further development of the locking unit according to the invention, the magnetic field changing means can comprise a plurality of changing elements, each of which has a constant material thickness along the longitudinal axis, wherein all changing elements have or can generate different thicknesses or material thicknesses and / or different magnetic permeabilities. Thus, each individual changing element has its own, constant material thickness and / or magnetic permeability. However, each individual changing element has a different material thickness and / or magnetic permeability than the other changing elements. Depending on the number of changing elements, several positions of the piston can then be clearly sensed. The changing elements can be arranged adjacent to one another in the longitudinal direction, either directly or indirectly.

[0030] According to a further development of the locking unit according to the invention, the change elements can be sorted along the longitudinal axis according to increasing material thickness and / or increasing magnetic permeability. This advantageously results in a gradation that enables incremental detection across multiple locations. The incremental gradation can be used to perform a plausibility check on data acquired by the multi-dimensional Hall sensor.

[0031] According to a further development of the locking unit according to the invention, a magnetic field passage can be formed between adjacent change elements along the longitudinal axis. Each magnetic field passage has a magnetic permeability that differs from the magnetic permeabilities of the two adjacent change elements. Through the magnetic field passage, the field lines of the magnetic field can pass unchanged from the magnetic field change means to the multi-dimensional Hall sensor. This leads to so-called peaks in the signal of the multi-dimensional Hall sensor, which then serve for the plausibility check, since adjacent change elements can be easily distinguished from one another.

[0032] According to a conceivable development of the locking unit according to the invention, the respective magnetic field passage can have a higher or lower magnetic permeability than both adjacent change elements. The signal peak is then distinct and contributes to operational reliability.

[0033] According to a conceivable development of the locking unit according to the invention, the respective magnetic field passage can be formed integrally from the piston wall or formed in multiple pieces with the piston wall. The first case is advantageous because no separate component needs to be provided as a magnetic field passage. The magnetic field passage can, for example, be formed directly during manufacture of the piston. The second case is advantageous because here a piston that is the same for many different locking units can be used (the common part reduces manufacturing and logistics costs), which can be provided with the appropriate magnetic field passage depending on the application. The magnetic field passage can be manufactured separately from the piston and then firmly connected to it.

[0034] According to a conceivable development of the locking unit according to the invention, the magnetic field passages can have identical magnetic permeabilities, preferably all of them. This design also serves for plausibility testing, since it prevents any measured value of the magnetic field that has passed through a change element from being confused with a measured value of the magnetic field that has passed through a magnetic field passage. Preferably, the magnetic permeability of the magnetic field passages in the detection area is unique. Since the magnetic field passages then have their own permeability, they cannot be confused with other components.

[0035] According to a conceivable development of the locking unit according to the invention, the at least one modification element can be formed from a ferromagnetic element, which is a separate component from the piston or an integral section of the piston. The separate design enables the piston to be manufactured as a common part and the modification element to be adapted to different requirements. The integral design reduces the number of manufacturing steps, as there is no need to arrange a separately manufactured modification element on the piston. Furthermore, there is no risk of accidental detachment.

[0036] According to a further development of the locking unit according to the invention, the at least one modification element can be formed from a film, a plate, a hollow cylinder, a coating, preferably a galvanic coating, a recess, preferably in the piston wall, or a region of the piston wall with modified permeability. It is conceivable that the at least one modification element consists of or comprises a ferromagnetic material. This material has particularly good properties for modifying the magnetic field. There are certainly several possibilities for modifying the magnetic permeability in the detection area.

[0037] A foil, which can be a ferromagnetic foil, can be easily realized in different magnetic permeabilities and can be easily arranged on the piston as a separately manufactured component.

[0038] A plate, which can be a ferromagnetic plate, or a hollow cylinder, which can be a ferromagnetic hollow cylinder, as a separately manufactured component, can, for example, be easily prefabricated and then assembled. It is also conceivable for the piston to be, at least in sections, a plastic injection-molded part made of a thermoplastic, and for the plate / hollow cylinder to be designed as an insert of the injection-molded part.

[0039] A coating, which can be a ferromagnetic coating, has the advantage of offering the benefits of a separately manufactured component (identical part of the piston and application-specific adaptation), while also realizing the advantages of an integral design, since it is first formed directly on the piston. Electroplating the piston to create at least one modification element offers significant advantages over separately manufactured components, as a galvanized layer does not dissolve even after long periods of operation. This ensures high operational reliability. The ferromagnetic coating can advantageously comprise nickel.

[0040] The recess can be a base-encompassing recess, meaning it is not continuous. This can lend stability to the piston. The recess can also be a continuous recess, meaning it opens towards the interior of the piston. The principle of the recess as a change element is based on the idea that the magnetic field itself has to cross less material, resulting in a change compared to a magnetic field that has to cross a thicker material that dissipates the magnetic field. The recess therefore creates a lower or higher magnetic permeability in the recessed area. Recesses can easily be formed in the piston wall itself, which is why no separately manufactured component is required.These recesses can be provided directly during production of the piston, for example in an injection mold, and / or can be introduced subsequently by material removal after the piston has been produced. The material removal can be carried out mechanically or by laser, resulting in a mechanical recess or a laser recess. Laser ablation is particularly advantageous because it allows very small changing elements to be created. The at least one recess can also define a changing element in combination with a film, a plate, a hollow cylinder, a coating, preferably a galvanic coating, or a region of the piston wall with modified permeability. The aforementioned elements can, for example, be formed or arranged in the recess, resulting in combined effects.

[0041] A permeability-modified area can be a section of the piston wall that was subsequently machined after the piston was produced in order to change the magnetic conductivity in this area compared to an unchanged area. It is conceivable, for example, that the permeability-modified area is a laser-irradiated area. This results in a chemical transformation in the irradiated area and a change in the magnetic permeability. Laser hardening is particularly advantageous because very small change elements can be created here. The advantage over material removal is that the sliding properties of the piston are not impaired by any wear-promoting steps and edges. Another advantage is that removing material avoids typical residues on the piston, such as grinding grooves. It is conceivable, for example, that the permeability-modified area is an etched area.Etching is particularly advantageous because it also allows for the creation of very small alterations. Another advantage over material removal is that the piston's sliding properties are not impaired by any wear-promoting steps and edges. Another advantage is that removing material prevents typical piston residues, such as grinding grooves. Furthermore, etching is a cold process compared to laser irradiation, requiring less energy.

[0042] Combinations of the above-mentioned modification elements are also conceivable, so that the magnetic field modification device can comprise different modification elements. This can lead to cost and complexity reduction.

[0043] According to a further development of the locking unit according to the invention, the multi-directional Hall sensor can comprise a temperature sensor, and the locking unit can be designed to perform temperature compensation of the sensor signals detected by the multi-directional Hall sensor using a temperature value detected by the temperature sensor. It is conceivable that a component temperature or temperature within the locking unit influences the magnetic field strength of the permanent magnet; for example, it can reduce it. Therefore, at certain temperatures, a position of the piston could be incorrectly assumed that does not correspond to the actual position and / or does not correspond to the initially learned position. Using temperature compensation, the measured magnetic field strength can then be offset against a temperature correction value in order to eliminate the temperature influence on the magnetic field strength.

[0044] According to a conceivable development of the locking unit according to the invention, the piston can be magnetically permeable in the detection area, preferably in the entire detection area, preferably made of a non-ferromagnetic material. This ensures that every orientation of the permanent magnet to the multi-directional Hall sensor can be sensed and that there are no "magnetic blind spots" where the magnetic field is isolated from the multi-directional Hall sensor and therefore cannot act on the multi-directional Hall sensor.

[0045] It is conceivable that the piston in the detection area is made at least partially from a thermoplastic, preferably as an injection-molded plastic part. Plastics such as thermoplastics are particularly suitable because, as non-conductors, they are permeable to electromagnetic waves up to 100 GHz. ABS (acrylonitrile butadiene styrene copolymers) is a particularly suitable thermoplastic because it is also suitable for electroplating. It is therefore conceivable that the piston in the detection area is constructed as an ABS part and provided with a galvanized coating as a modification element to create a electroplating effect.

[0046] It is conceivable that the piston in the detection area could be made of stainless steel, at least in sections. Stainless steel or high-alloy steel is advantageously rust- and acid-resistant, but also less magnetic than steels with fewer or no alloying additives, such as chromium. Stainless steel is therefore suitable as a construction material for components or sections of components that are less magnetic than components made of unalloyed or free-cutting steel.

[0047] It is conceivable that the piston in the detection area is made of a ferromagnetic metal. In this case, laser irradiation can be performed particularly easily, for example, for laser hardening or laser ablation.

[0048] A combination of these is conceivable, namely, that the piston in the detection area is made of a non-ferromagnetic and a ferromagnetic metal. This allows the inventive effect to be realized in a structurally simple manner. The ferromagnetic section shields the magnetic field of the permanent magnet considerably more effectively than the non-ferromagnetic section, which allows the magnetic field to pass through to the sensor unchanged.

[0049] According to a conceivable development of the locking unit according to the invention, the piston can be designed without any openings or closed in the detection area. Therefore, at least in the detection area, no fluidic exchange can take place between the piston interior and the area surrounding the piston. This leads to outstanding sliding properties and enables fluidic separation, so that dirt particles in the fluid, which could potentially distort the magnetic field of the permanent magnet and thus influence the signal quality, are sealed off. Especially in a conceivable application context in which the locking unit can be installed surrounded by transmission oil, which may contain, for example, steel particles due to wear, this fluidic separation ensures high signal quality even over a long service life.

[0050] According to a conceivable development of the locking unit according to the invention, the multi-directional Hall sensor can be arranged at an opening in the housing through which the piston extends. Thus, the multi-directional Hall sensor and the permanent magnet are positioned as close to each other as possible. This allows a high field strength to be achieved at the multi-directional Hall sensor with a relatively small permanent magnet.

[0051] According to a conceivable development of the locking unit according to the invention, the piston can comprise a multi-part piston tube. The piston tube can comprise a first piston tube part, preferably made of a ferromagnetic material, a second piston tube part, preferably made of a non-ferromagnetic material, which directly adjoins the first piston tube part in the longitudinal direction, and a third piston tube part, preferably made of a non-ferromagnetic material, which is arranged circumferentially to the first and second piston tube parts and covers the joint between the first and second piston tube parts. The third piston tube part can guide the piston relative to the housing. The effect according to the invention can thus be realized in a structurally simple manner.The ferromagnetic section shields the magnetic field of the permanent magnet considerably more than the non-ferromagnetic section, which allows the magnetic field to pass through to the sensor unchanged.

[0052] According to the invention, a sensor unit is also proposed which is formed from a permanent magnet, a multi-spatial direction Hall sensor for detecting a magnetic field of the permanent magnet and a magnetic field changing means, wherein one of the permanent magnet and the multi-spatial direction Hall sensor is arranged or can be arranged in a stationary manner and the other of the permanent magnet and the multi-spatial direction Hall sensor is adjustable along a first movement path, wherein the magnetic field changing means is adjustable in a space between the permanent magnet and the multi-spatial direction Hall sensor along a second movement path, wherein the magnetic field changing means defines at least two regions of different magnetic permeability in the space.

[0053] The advantages already described above with regard to the locking unit in the specific application context also apply analogously to the context-free sensor unit, to which reference is hereby made. The above statements regarding the locking unit also apply analogously to the sensor unit without context, i.e., without reference to a locking unit. The two movement paths can advantageously be arranged parallel to each other to ensure a reliable change of the magnetic field in any position of the permanent magnet or multi-spatial direction Hall sensor.

[0054] Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. They show: Fig. 1 a longitudinal sectional view of a locking unit according to the first embodiment, Fig. 2 another longitudinal sectional view of the locking unit, Fig. 3 a detailed view after Fig. 1, Fig. 4 a detailed view after Fig. 2, Fig. 5 a longitudinal sectional view of a locking unit according to a further embodiment, Fig. 6 a longitudinal sectional view of a locking unit according to a further embodiment, Fig. 7 a longitudinal sectional view of a locking unit according to a further embodiment, Fig. 8 a longitudinal sectional view of a locking unit according to a further embodiment, Fig. 9 a longitudinal sectional view of a locking unit according to a further embodiment in the first position, Fig. 10 a longitudinal sectional view of the locking unit according to Fig. 9 in further position, Fig. 11 a longitudinal sectional view of the locking unit according to Fig. 9 in further position, Fig. 12 a longitudinal sectional view of a locking unit according to a further embodiment, Fig. 13 a longitudinal sectional view of a locking unit according to a further embodiment and Fig. 14 a sensor arrangement.

[0055] In the figures, identical or corresponding elements are each designated by the same reference numerals and are therefore not described again unless expedient. Features already described are not described again to avoid repetition and are applicable to all elements with identical or corresponding reference numerals, unless explicitly excluded. The disclosures contained in the entire description are analogously transferable to identical parts with identical reference numerals or identical component designations. The positional information chosen in the description, such as top, bottom, side, etc., also relates to the directly described or illustrated figure and, in the event of a change in position, is to be transferred analogously to the new position.Furthermore, individual features or combinations of features from the different embodiments shown and described can also represent independent, inventive or inventive solutions.

[0056] In the Fig. 1 to 4, a locking unit 2 according to the invention is shown in two different states. The locking unit 2 comprises a housing 4 through which a longitudinal axis L extends, with a radial direction R projecting therefrom. A longitudinal direction runs along the longitudinal axis L. The housing 4 has an opening 38 at one end, and an electromagnet 8 is connected to the other end.

[0057] The electromagnet 8 is in the Fig. 1 and Fig. 3 and comprises a core 40, a coil carrier 42, a coil 44 wound thereon, a yoke part 46, an armature 16 and an armature rod 18 firmly connected thereto. The armature 16 and the armature rod 18 are adjustable along the longitudinal axis L. In the Fig. 1 and Fig. 3, the anchor 16 is tightened and therefore adjusted along the longitudinal axis L by the adjustment path V toward the core 40. A connecting rod 68 is fixedly connected to the anchor rod 18 by means of a joint 66. The connecting rod 68 extends the anchor rod 18 longitudinally toward the opening 38.

[0058] The locking unit 2 has a piston 6 which can be moved along the longitudinal axis L between a retracted position S1 ( Fig. 1 and Fig. 3) and an extended position S2 ( Fig. 2 and Fig. 4) is adjustable. In the locking unit 2 shown, the piston 6 comprises several parts, namely at least one piston tube 48 partially protruding from the opening 38 and a piston pressure piece 50. The piston pressure piece 50 is guided on the outer circumference. The piston pressure piece 50 has locking receptacles 12, 14 on its inner radial side, which are axially spaced from one another (relative to the longitudinal axis L) and are designed as ring-like bulges. The locking receptacles 12, 14 are arranged on the inner surface of the piston pressure piece 50 as a step or internal shoulder. The piston 6 also has a pressure surface 52, which is formed on the piston pressure piece 50 and delimits a pressure chamber 54 that can be filled with a fluid. The piston 6 can be moved from its retracted position S1 to its extended position S2 by the pressure of the fluid in the pressure chamber 54. This fluid pressure displaces the piston 6 to the right in the image plane, i.e. further through the opening 38.

[0059] The locking unit 2 comprises a guide element 20, locking elements 10 and locking element bores 56. The guide element 20 is firmly connected to the anchor rod 18 and is therefore adjustable along the longitudinal axis L. Here, the guide element 20 is adjustable between a locking position P1 ( Fig. 2 and Fig. 4) and a release position P2 ( Fig. 1 and Fig. 3) adjustable. The locking element bores 56 are stationary, here as an example in the yoke part 46, and oriented in the radial direction R and serve to accommodate the locking elements 10. Each locking element bore 56 is assigned a locking element 10. The locking elements 10 are designed as balls here. The guide element 20 has a conical surface 58, which presses the locking elements 10, depending on the position P1, P2, outward in the radial direction R through the locking element bores 56 into the corresponding locking receptacles 12, 14. In Fig. 1 and Fig. 3, the guide element 20 is, however, moved into its release position P2, so that the locking elements 10 are not forced radially outwards by the conical surface 58 and therefore do not engage in a locking manner in any locking receptacle 12, 14 and thus the piston 6 is adjustable along the longitudinal axis L. In contrast, in Fig. 2 and Fig. 4 the guide element 20 is moved into its locking position P1, so that the locking elements 10 engage in the respective locking receptacle 12 and consequently the piston 6 is fixed against adjustment along the longitudinal axis L by the holding interaction of the locking elements 10 with the respective locking receptacle 12. The piston 6 can thus be locked in each position S1, S2, because in the retracted position S1 the locking elements 10 can be pressed into the second locking receptacle 14 and in the extended position S2 the locking elements 10 can be pressed into the first locking receptacle 12. An anchor rod part 60 is arranged on the anchor rod 18 and rests against the guide element 20.

[0060] A preload spring 62, which can be designed as a helical compression spring, is supported between the yoke part 46 and the armature rod part 60. Alternatively, it could also be supported directly on the guide element 20. The preload spring 62 preloads the guide element 20 into an end position, which is defined here as the locking position P1. From this locking position P1, the guide element 20 can be moved into the release position P2 by energizing the coil 44, attracting the armature 16, and longitudinally adjusting the armature rod 18. The spring force of the preload spring 62 and the tensile force of the electromagnet 8 are oppositely directed.

[0061] A piston compression spring 64, which may be designed as a helical compression spring, is supported between the piston 6 and the housing 4. It presses the piston 6 into its retracted position S1. The spring force of the piston compression spring 64 and the pressure force of the fluid in the pressure chamber 54 are oppositely directed.

[0062] The electromagnet 8 is in the Fig. 2 and Fig. 4 is shown de-energized. This pushes the preload spring 62 into its locking position P1. The piston 6 is moved into its extended position S2 by fluid pressure. The locking elements 10 are pressed by the guide element 20 into the first locking receptacle 12. The extended position S2 of the piston is thus secured.

[0063] The locking unit 2 also has a sensor unit formed from a permanent magnet 22, a multi-directional Hall sensor 24 that detects the magnetic field of the permanent magnet 22, and a magnetic field changing means 26 on the piston 6. The locking unit 2 can also include an evaluation unit 70, which can also form the sensor unit. The evaluation unit 70 can be connected to the multi-directional Hall sensor 24 via a signal connection 72. The multi-directional Hall sensor 24 can include a temperature sensor 36 that can measure a component temperature or the temperature within the locking unit 2. The multi-directional Hall sensor 24 has a plurality of Hall elements arranged within a single sensor housing 76.

[0064] The permanent magnet 22 is arranged within the piston 6 and generates a magnetic field that propagates outwards in the radial direction R. The magnetic field of the permanent magnet 22 crosses the piston wall 34 of the piston 6. The permanent magnet 22 is arranged at one end on the connecting rod 68 opposite the electromagnet 8. The connecting rod 68 extends within the piston 6. The permanent magnet 22 is therefore fixedly connected to the armature 16, armature rod 18, guide element 20, and connecting rod 68. Due to the advantageous coupling of the permanent magnet 22 to the guide element 20, the permanent magnet 22 moves with the guide element 20. The permanent magnet 22 and the guide element 20 are therefore immobile relative to one another. The piston 6 guides the permanent magnet 22 and / or the connecting rod 68 radially by means of a floating bearing.

[0065] The multi-directional Hall sensor 24 is fixedly mounted in an end flange 74 of the housing 4 and radially arranged relative to the permanent magnet 22 and the piston wall 34. It is therefore immobile relative to the housing 4. The multi-directional Hall sensor 24 is also located at the opening 38 of the housing 4. The magnetic field of the permanent magnet 22 acts on the multi-directional Hall sensor 24.

[0066] A gap 30 is formed between the permanent magnet 22 and the multi-directional Hall sensor 24. This gap 30 is penetrated by the piston 6 or its piston wall 34. The region of the piston 6 that is adjustable in the radial direction R along the stationary multi-directional Hall sensor 24 through the gap 30 defines a detection area 28 in the longitudinal direction. This detection area 28 is traversed by the magnetic field of the permanent magnet 22, regardless of the position of the piston 6.

[0067] The magnetic field modifying means 26 is arranged in this detection region 28 and fixedly attached to the piston 6. The magnetic field modifying means 26 has a magnetic permeability that differs from a magnetic permeability in another region or at another location on the piston wall 34 in the detection region, so that different magnetic permeabilities are formed in the detection region 28 along the longitudinal axis L.

[0068] The location of the permanent magnet 22 and thus of the guide element 20 can be determined via a magnetic field incidence angle, which the multi-directional Hall sensor 24 can calculate from the sensed magnetic field. The location of the magnetic field modifying means 26 and thus of the armature 6 can be determined via the magnetic field strength, which the multi-directional Hall sensor 24 can sense.

[0069] The piston tube 48 is constructed in several parts and comprises a first piston tube part 48a made of a ferromagnetic material, a second piston tube part 48b made of a non-ferromagnetic material, which directly adjoins the first piston tube part 48a in the longitudinal direction, and a third piston tube part 48c made of a non-ferromagnetic material, which is arranged circumferentially to the piston tube parts 48a, 48b and covers the joint 49 between the two piston tube parts 48a, 48b. The third piston tube part 48c guides the piston 6 in the opening 38 relative to the housing 4. The first piston tube part 48a has, at its axial end, a magnetic field changing means 26 in the form of a recess in the piston wall 34 and a changing means 26a arranged therein and manufactured separately from the piston wall 34.

[0070] The changing means 26a has a magnetic permeability that differs from a magnetic permeability at another location in the detection area 28. Therefore, if the magnetic field of the permanent magnet 22 now crosses the changing means 26a, the magnetic field is changed accordingly, and the assigned position of the guide element 20 can be assumed. If no corresponding change in the magnetic field relative to the multi-dimensional Hall sensor 24 occurs, this position of the guide element 20 cannot be assumed.

[0071] The following are intended to provide information regarding Fig. 5 to 13 different designs of magnetic field changing means 26 are described. These designs or combinations thereof can certainly be used in the locking unit 2 of the Fig. 1 to 4 apply and shall be deemed to be disclosed in combination therewith, unless technically contradictory.

[0072] Fig. Figure 5 shows a longitudinal section of a magnetic field modifying means 26 in the intermediate space 30, which is manufactured separately from the piston wall 34 and firmly connected to the piston 6. The magnetic field modifying means 26 comprises several modifying elements 26a, 26b, 26c, 26d, each of which has a constant material thickness along the longitudinal axis L and is indirectly adjacent to one another in the longitudinal direction. The modifying elements 26a, 26b, 26c, 26d extend only in parts of the detection area 28. However, it is evident that all modifying elements 26a, 26b, 26c, 26d have different material thicknesses and / or are made of different magnetically permeable materials. Since four change elements 26a, 26b, 26c, 26d are provided here, four different positions of the piston 6 can be sensed, depending on which of the four change elements 26a, 26b, 26c, 26d changes the magnetic field in front of the multi-space direction Hall sensor 24.The modification elements 26a, 26b, 26c, 26d are sorted along the longitudinal axis L with respect to increasing material thickness and / or increasing magnetic permeability. It is also evident that a magnetic field passage 32 is formed between each modification element 26a, 26b, 26c, 26d adjacent along the longitudinal axis L. The magnetic field passages 32 are formed integrally from the piston wall 34 and have a higher or lower magnetic permeability than the two adjacent modification elements 26a, 26b, 26c, 26d. The magnetic field passages 32 all have identical magnetic permeabilities. The modification elements 26a, 26b, 26c, 26d can, for example, be formed from a film, a plate, a hollow cylinder, or a coating. The piston 6 is magnetically permeable throughout the entire detection area 28. In the state shown, the magnetic field of the permanent magnet 22 crosses one of the magnetic field passages 32 along the magnetic arrow M.The permanent magnet 22 can be located, but the magnetic field changing means 26 cannot, since it is not crossed by the magnetic field of the permanent magnet 22 to the multi-spatial direction Hall sensor 24. The permanent magnet 22 is adjustable along a first movement path B1 along the longitudinal axis L. The magnetic field changing means 26 is adjustable along a second movement path B2 along the longitudinal axis L.

[0073] Fig. Figure 6 shows a longitudinal section of a magnetic field modifying means 26, which is formed integrally from the piston wall 34. The magnetic field modifying means 26 comprises a plurality of modifying elements 26a, 26b, 26c, 26d, each of which has a constant material thickness along the longitudinal axis L and is indirectly adjacent to one another in the longitudinal direction. The modifying elements 26a, 26b, 26c, 26d extend only in parts of the detection area 28. However, it is evident that all modifying elements 26a, 26b, 26c, 26d have different material thicknesses and / or are made of different magnetically permeable materials. Since four change elements 26a, 26b, 26c, 26d are provided here, four different positions of the piston 6 can be sensed, depending on which of the four change elements 26a, 26b, 26c, 26d changes the magnetic field in front of the multi-space direction Hall sensor 24.The change elements 26a, 26b, 26c, 26d are sorted along the longitudinal axis L with respect to increasing material thickness and / or increasing magnetic permeability. It is also evident that a magnetic field passage 32 is formed between each change element 26a, 26b, 26c, 26d adjacent along the longitudinal axis L. The magnetic field passages 32 are formed integrally from the piston wall 34 and have a higher or lower magnetic permeability than the two adjacent change elements 26a, 26b, 26c, 26d. The magnetic field passages 32 all have identical magnetic permeabilities. The piston 6 is magnetically permeable throughout the entire detection area 28. In the state shown, the magnetic field of the permanent magnet 22 traverses one of the magnetic field passages 32 along the magnetic arrow M.The permanent magnet 22 can be located, but the magnetic field changing means 26 cannot, since it is not crossed by the magnetic field of the permanent magnet 22 to the multi-spatial direction Hall sensor 24. The permanent magnet 22 is adjustable along a first movement path B1 along the longitudinal axis L. The magnetic field changing means 26 is adjustable along a second movement path B2 along the longitudinal axis L.

[0074] Fig. 7 shows a longitudinal section of a magnetic field modifying means 26 in the intermediate space 30, which is manufactured separately from the piston wall 34, is firmly connected to the piston 6, and has an increasing material thickness and / or increasing magnetic permeability along the longitudinal axis L. The magnetic field modifying means 26 comprises a single modifying element 26a, which is designed as a wedge. The magnetic field modifying means 26 with increasing material thickness and / or increasing magnetic permeability extends along the longitudinal axis L over the entire detection area 28. Since the magnetic permeability changes along the longitudinal axis L, any position of the piston 6 can be sensed here. The separately manufactured single modifying element 26a can be formed, for example, from a film, a plate, a hollow cylinder, or a coating. The piston 6 is magnetically permeable throughout the entire detection area 28.In the illustrated state, the magnetic field of the permanent magnet 22 traverses the change element 26a along the magnetic arrow M. The permanent magnet 22 and the magnetic field change means 26 can be positioned. The permanent magnet 22 is adjustable along a first movement path B1 along the longitudinal axis L. The magnetic field change means 26 is adjustable along a second movement path B2 along the longitudinal axis L.

[0075] Fig. 8 shows a longitudinal section of a magnetic field changing means 26, which is formed integrally from the piston wall 34 and has an increasing material thickness and / or increasing magnetic permeability along the longitudinal axis L. The magnetic field changing means 26 comprises a single changing element 26a, which is designed as a wedge. The magnetic field changing means 26 with increasing material thickness and / or increasing magnetic permeability extends along the longitudinal axis L over the entire detection area 28. Since the magnetic permeability changes along the longitudinal axis L, every position of the piston 6 can be sensed here. The piston 6 is magnetically permeable in the entire detection area 28. In the state shown, the magnetic field of the permanent magnet 22 traverses the changing element 26a along the magnetic arrow M. A location of the permanent magnet 22 and a location of the magnetic field changing means 26 can be performed.The permanent magnet 22 is adjustable along a first movement path B1 along the longitudinal axis L. The magnetic field changing means 26 is adjustable along a second movement path B2 along the longitudinal axis L.

[0076] In the Fig. Figures 9 to 11 show different states of an embodiment. Fig. 9 to 11 each show a longitudinal section of a magnetic field modifying means 26 in the intermediate space 30, which is manufactured separately from the piston wall 34 and is firmly connected to the piston 6. The magnetic field modifying means 26 comprises two modifying elements 26a, 26b, each of which has a constant material thickness along the longitudinal axis L and is indirectly adjacent to one another in the longitudinal direction. The modifying elements 26a, 26b extend only in parts of the detection area 28. One modifying element 26a is assigned to the extended position S2 of the piston 6, and one modifying element 26b is assigned to the retracted position S1 of the piston 6. It can be seen that all modifying elements 26a, 26b have different material thicknesses and / or are made of different magnetically permeable materials.Since two change elements 26a, 26b are provided here, two different positions of the piston 6 can be sensed, depending on which of the two change elements 26a, 26b changes the magnetic field in front of the multi-spatial direction Hall sensor 24. It can be seen that a magnetic field passage 32 is formed between adjacent change elements 26a, 26b along the longitudinal axis L. The magnetic field passage 32 is formed integrally from the piston wall 34 and has a higher or lower magnetic permeability than the two adjacent change elements 26a, 26b. The separately manufactured change elements 26a, 26b can be formed, for example, from a film, a plate, a hollow cylinder, or a coating. The piston 6 is magnetically permeable throughout the detection area 28. The permanent magnet 22 is adjustable along a first movement path B1 along the longitudinal axis L.The magnetic field changing means 26 is adjustable along a second movement path B2 along the longitudinal axis L.

[0077] In the shown condition of the Fig. 9, the magnetic field of the permanent magnet 22 crosses the change element 26a along the magnetic arrow M. The change element 26a therefore changes the magnetic field detectable by the multi-directional Hall sensor 24 relative to another location in the detection area 28, for example, relative to the magnetic field passage 32. The magnetic field incidence angle can be calculated from the magnetic field, with one magnetic field incidence angle being assigned to the position P1 and another magnetic field incidence angle being assigned to the position P2 of the guide element 20. Here, the release position P2 is sensed. The position of the piston 6 can be determined from the magnetic field strength, which is assigned to a position of the piston 6; with respect to Fig. 9, the extended position S2 is sensed. Piston 6 is therefore released in its extended position S2.

[0078] In the shown condition of the Fig. 10, the magnetic field of the permanent magnet 22 now crosses the change element 26b along the magnetic arrow M. The change element 26b therefore changes the magnetic field detectable by the multi-directional Hall sensor 24 relative to another location in the detection area 28, for example, relative to the magnetic field passage 32. Here, too, the magnetic field angle of incidence can be calculated from the magnetic field to determine the position of the guide element 20. Here, the locking position P1 is sensed. The position of the piston 6 can be determined based on the magnetic field strength associated with a position of the piston 6; with respect to Fig. 10, the retracted position S1 is sensed. Piston 6 is therefore locked in its retracted position S1.

[0079] In the shown condition of the Fig. 11, the magnetic field of the permanent magnet 22 crosses the magnetic field passage 32 along the magnetic arrow M. Therefore, no change element 26a, 26b changes the magnetic field detectable by the multi-directional Hall sensor 24. The magnetic field angle of incidence, to which a position P1, P2, or intermediate position of the guide element 20 is / can be assigned, can be calculated from the magnetic field. The position of the piston 6 cannot be determined from the magnetic field strength, since no change element 26a, 26b enters the detectable magnetic field in front of the multi-directional Hall sensor 24 and changes it. Thus, when the magnetic field crosses the magnetic field along the magnetic arrow M between the two change elements 26a, 26b, the multi-directional Hall sensor 24 cannot sense the position of the piston 6. The position of the piston 6 is unknown.

[0080] Fig. Figure 12 shows a longitudinal section of a magnetic field modifying means 26, which is formed integrally from the piston wall 34. The magnetic field modifying means 26 comprises a plurality of modifying elements 26a, 26b, 26c, 26d, each of which has a constant thickness along the longitudinal axis L and is indirectly adjacent to one another in the longitudinal direction. The modifying elements 26a, 26b, 26c, 26d extend only in parts of the detection area 28. However, it is evident that all modifying elements 26a, 26b, 26c, 26d have different thicknesses and, in this case, also lead to different material thicknesses of the piston wall 34 in the radial direction R adjacent to the respective modifying element 26a, 26b, 26c, 26d.Since four change elements 26a, 26b, 26c, 26d are provided here, four different positions of the piston 6 can be sensed, depending on which of the four change elements 26a, 26b, 26c, 26d changes the magnetic field in front of the multi-spatial direction Hall sensor 24. The change elements 26a, 26b, 26c, 26d are sorted along the longitudinal axis L with respect to increasing material thickness and / or increasing magnetic permeability. It is also evident that a magnetic field passage 32 is formed between each change element 26a, 26b, 26c, 26d adjacent along the longitudinal axis L. The magnetic field passages 32 are formed integrally from the piston wall 34 and have a higher or lower magnetic permeability than the two adjacent change elements 26a, 26b, 26c, 26d. The magnetic field passages 32 all have identical magnetic permeabilities.The change elements 26a, 26b, 26c, 26d are each formed from a recess in the piston wall 34. The piston 6 is magnetically permeable throughout the detection area 28. In the illustrated state, the magnetic field of the permanent magnet 22 traverses one of the magnetic field passages 32 along the magnetic arrow M. The permanent magnet 22 can be located, but the magnetic field change means 26 cannot be located, since it is not traversed by the magnetic field of the permanent magnet 22 on its way to the multi-dimensional Hall sensor 24. The permanent magnet 22 is adjustable along a first movement path B1 along the longitudinal axis L. The magnetic field change means 26 is adjustable along a second movement path B2 along the longitudinal axis L.

[0081] Fig. Figure 13 shows a longitudinal section of a magnetic field modifying means 26. The magnetic field modifying means 26 comprises a plurality of modifying elements 26a, 26b, 26c, 26d, each of which is indirectly adjacent to one another in the longitudinal direction. The modifying elements 26a, 26b, 26c, 26d each have a constant material thickness along the longitudinal axis L, with all modifying elements 26a, 26b, 26c, 26d having different magnetic permeabilities. The change elements 26a, 26b, 26c, 26d extend only over parts of the detection area 28. Since four change elements 26a, 26b, 26c, 26d are provided here, four different positions of the piston 6 can be sensed, depending on which of the four change elements 26a, 26b, 26c, 26d changes the magnetic field in front of the multi-spatial direction Hall sensor 24. The change elements 26a, 26b, 26c, 26d are sorted along the longitudinal axis L in order of increasing magnetic permeability.It is also evident that a magnetic field passage 32 is formed between each of the adjacent change elements 26a, 26b, 26c, 26d along the longitudinal axis L. The magnetic field passages 32 are formed integrally from the piston wall 34 and have a higher or lower magnetic permeability than the two adjacent change elements 26a, 26b, 26c, 26d. The magnetic field passages 32 all have identical magnetic permeabilities. The change elements 26a, 26b, 26c, 26d are each formed from a region of the piston wall 34 with a modified magnetic permeability. The piston 6 is magnetically permeable throughout the entire detection area 28. In the state shown, the magnetic field of the permanent magnet 22 traverses one of the magnetic field passages 32 along the magnetic arrow M.The permanent magnet 22 can be located, but the magnetic field changing means 26 cannot, since it is not crossed by the magnetic field of the permanent magnet 22 to the multi-spatial direction Hall sensor 24. The permanent magnet 22 is adjustable along a first movement path B1 along the longitudinal axis L. The magnetic field changing means 26 is adjustable along a second movement path B2 along the longitudinal axis L.

[0082] In Fig.14 shows an application-context-free sensor unit formed from a permanent magnet 22, a multi-spatial-direction Hall sensor 24 for detecting a magnetic field of the permanent magnet 22, and a magnetic field-changing means 26. The multi-spatial-direction Hall sensor 24 is arranged or can be arranged in a fixed location, and the permanent magnet 22 is adjustable along the first movement path B1. The magnetic field-changing means 26 is adjustable in the intermediate space 30 between the permanent magnet 22 and the multi-spatial-direction Hall sensor 24 along a second movement path B2, the magnetic field-changing means 26 defining at least two permeability regions D1, D2 of different magnetic permeability in the intermediate space 30. The movement paths B1, B2 are arranged parallel to one another. The magnetic field-changing means 26 can be configured as mentioned above.

[0083] The invention is not limited to one of the above-described embodiments, but can be modified in a variety of ways. All features and advantages apparent from the claims, the description, and the drawings, including structural details, spatial arrangements, and method steps, may be essential to the invention both individually and in a wide variety of combinations.

[0084] The scope of the invention includes all combinations of at least two of the features disclosed in the description, the claims and / or the figures.

[0085] To avoid repetition, features disclosed by the device should also be considered as disclosed by the method and claimable. Likewise, features disclosed by the method should also be considered as disclosed by the device and claimable. List of reference symbols 2 locking unit 4 housings 6 pistons 8 Electromagnet 10 locking element 12 first snap shot 14 second locking receptacle 16 anchors 18 anchor rod 20 guide element 22 permanent magnet 24 multi-room direction Hall sensor 26 magnetic field modification agents 26a-26d Change element 28 Detection range 30 space 32 Magnetic field passage 34 Piston wall 36 Temperature sensor 38 Opening 40 core 42 coil carriers 44 coil 46 yoke part 48 Piston tube 48a first piston tube part 48b second piston tube part 48c third piston tube part 49 push 50 piston pressure piece 52 printing area 54 Printing room 56 locking element hole 58 conical surface 60 anchor rod part 62 preload spring 64 piston compression spring 66 joint 68 connecting rod 70 Evaluation unit 72 Signal connection 74 Flange 76 sensor housings B1 first movement path B2 second movement path D1 Permeability range D2 permeability range L Longitudinal axis M Magnetic Arrow P1 Locking position P2 release position R Radial direction S1 retracted position S2 extended position V adjustment range

Claims

[1] Locking unit (2), comprising a housing (4) through which a longitudinal axis (L) passes, a piston (6) which is adjustable along the longitudinal axis (L) between a retracted retracted position (S1) and an extended extended position (S2), wherein the locking unit (2) serves to lock the movement of the piston (6) which can be subjected to pressure from a fluid, wherein the locking unit (2) has an electromagnet (8) and at least one locking element (10), wherein the piston (6) has at least one first locking receptacle (12) and a second locking receptacle (14), and the piston (6) can be secured by the holding interaction of the at least one locking element (10) with one of the locking receptacles (12, 14), wherein a guide element (20) is firmly connected to an armature (16) or an armature rod (18) of the electromagnet (8),which is adjustable along the longitudinal axis (L) between a locking position (P1) and a release position (P2) and, depending on the position (P1, P2), pushes the at least one locking element (10) radially outwards, , characterized bya sensor unit formed from a permanent magnet (22), a multi-spatial direction Hall sensor (24) for detecting a magnetic field of the permanent magnet (22) and a magnetic field changing means (26), wherein one of the permanent magnet (22) and the multi-spatial direction Hall sensor (24) is arranged in a stationary manner with respect to the housing (4) and the other of the permanent magnet (22) and the multi-spatial direction Hall sensor (24) is connected to the guide element (20) so as to be adjustable along the longitudinal axis (L), wherein the piston (6) extends through an intermediate space (30) between the permanent magnet (22) and the multi-spatial direction Hall sensor (24), wherein that region of the piston (6) which is adjustable radially adjacent along the stationary element of the permanent magnet (22) and the multi-spatial direction Hall sensor (24) through the intermediate space (30) defines a detection region (28), wherein the magnetic field changing means (26) is fixedly attached to the piston (6) is arranged,so that different magnetic permeabilities are formed in the detection area (28) along the longitudinal axis (L). [2] Locking unit (5) according to claim 1, characterized by that the magnetic field changing means (26) is formed integrally from a piston wall (34) or is formed in several pieces with a piston wall (34). [3] Locking unit (5) according to one of the preceding claims, characterized by in that the magnetic field changing means (26) comprises a single changing element (26a) which either has a constant material thickness and / or constant magnetic permeability along the longitudinal axis (L) and extends only in a part of the detection area (28) or has an increasing material thickness and / or increasing magnetic permeability along the longitudinal axis (L), preferably continuously increasing. [4] Locking unit (5) according to one of claims 1 to 2, characterized byin that the magnetic field changing means (26) comprises a plurality of changing elements (26a, 26b, 26c, 26d), each having a material thickness that remains constant along the longitudinal axis (L), wherein all changing elements (26a, 26b, 26c, 26d) have or generate different thicknesses or material thicknesses and / or different magnetic permeabilities. [5] Locking unit (5) according to claim 4, characterized by that the change elements (26a, 26b, 26c, 26d) are sorted along the longitudinal axis (L) with respect to increasing material thickness and / or increasing magnetic permeability. [6] Locking unit (5) according to one of claims 4 or 5, characterized by that a magnetic field passage (32) is formed between each of the change elements (26a, 26b, 26c, 26d) adjacent along the longitudinal axis (L). [7] Locking unit (5) according to one of claims 3 to 6, characterized bythat the at least one changing element (26a, 26b, 26c, 26d) is formed from a film, a plate, a hollow cylinder, a coating, preferably a galvanic coating, a recess, preferably in the piston wall (34), or a permeability-modified region of the piston wall (34). [8] Locking unit (5) according to one of the preceding claims, characterized by in that the multi-room direction Hall sensor (24) comprises a temperature sensor (36) and the locking unit (2) is designed to carry out temperature compensation of the sensor signals detected by the multi-room direction Hall sensor (24) by means of a temperature value detected by the temperature sensor (36). [9] Sensor unit which is formed from a permanent magnet (22), a multi-spatial direction Hall sensor (24) for detecting a magnetic field of the permanent magnet (22) and a magnetic field changing means (26), wherein one of the permanent magnet (22) and the multi-spatial direction Hall sensor (24) is arranged or can be arranged in a stationary manner and the other of the permanent magnet (22) and the multi-spatial direction Hall sensor (24) is adjustable along a first movement path (B1), wherein the magnetic field changing means (26) is adjustable in a space (30) between the permanent magnet (22) and the multi-spatial direction Hall sensor (24) along a second movement path (B2), wherein the changing element (26) defines at least two regions of different magnetic permeability in the space (30).

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