Electromagnetic stroke measurement system, magnet holder, and application of electromagnetic stroke measurement system

Abstract

The invention relates to an electromagnetic stroke measuring system having a tappet (5) having a longitudinal axis (L) pointing in the direction of stroke, wherein the tappet (5) is arranged in a housing (1) in the direction of the longitudinal axis (L) and is movable in the housing in the direction of the longitudinal axis (L), a magnet carrier (3) having a magnet (4) arranged in a magnet section (3a) of the magnet carrier (3), wherein the magnet carrier (3) is arranged on a radial periphery of the tappet (5) with respect to the longitudinal axis (L) such that the magnet carrier is movable together with the tappet (5) in the axial direction, and a sensor element (2) arranged on the side of the housing (1) facing away from the tappet (5) with respect to the longitudinal axis (L), wherein the housing (1) is configured with a guide (1a) in which the magnet section (3a) is guided at least sectionally in the direction of the longitudinal axis (L).

Description

Technical Field

[0001] The present invention relates to an electromagnetic travel measurement system, a magnet holder for such a travel measurement system, and an application of such a travel measurement system. Background Technology

[0002] To measure travel distance, an electromagnetic travel measurement system can be used, which includes, for example, a Hall sensor and a magnet. The Hall sensor measures the magnetic field emanating from the magnet. If the magnetic field around the Hall sensor changes, this is detected by the Hall sensor and transmitted accordingly to the analysis and processing system in an electronically pre-processed manner. Here, the quality and accuracy of the sensor system or the measurement results depend primarily on the strength and stability of the magnetic field at the corresponding measurement location. The strength of the magnetic field is determined by the distance between the magnet and the sensor in the lateral or radial and transverse directions.

[0003] Such an electromagnetic travel measurement system is installed, for example, in a foot brake module. Here, the electromagnetic travel measurement system determines the position of the pushrod within the foot brake module by the positional state of a magnet relative to a Hall sensor. The Hall sensor is mounted in a fixed position within the foot brake module and is therefore constant in all three spatial directions with respect to the housing, in which the pushrod moves. Through the travel movement of the pushrod, the magnet is guided past the sensor in the direction of travel movement, i.e., in the axial direction about the longitudinal axis of the pushrod, and detects the corresponding relative position. Relative movement of the magnet in other spatial directions is undesirable because such relative movement distorts the signal and thus distorts the assumed detected travel position.

[0004] In this context, EP 3 620 754 A1 discloses a magnet holder having a holding section circumferentially surrounding a push rod, wherein the holding section is guided through a housing notch. Here, a magnet section, held by the holding section and containing a magnet, is arranged outside the housing notch and protrudes in the direction of the sensor. Since the magnet holder is thus guided only in the section opposite to the magnet, a small relative movement in the region of the guide portion, for example in the circumferential direction of the push rod, results in a larger relative movement of the magnet section outside the notch. Furthermore, radial relative movement may occur. However, in addition, because the sensor is no longer separated from the guide space of the push rod by the housing notch, moisture and impurities can reach the sensor through the housing notch. This may also distort the measurement results or damage the sensor. Summary of the Invention

[0005] In view of the above embodiments, the objective of this invention is to provide an electromagnetic stroke measurement system, a magnet support, and an application of the electromagnetic stroke measurement system, through which stroke measurement can be reliably achieved.

[0006] This task is solved by the electromagnetic travel measurement system according to the invention, the magnet support according to the invention, and the application of such an electromagnetic travel measurement system according to the invention. Advantageous extensions of the invention are included in the technical solutions of the invention.

[0007] According to the present invention, the electromagnetic stroke measurement system has a push rod having a longitudinal axis pointing in the stroke direction, wherein the push rod is arranged in the direction of the longitudinal axis within a housing and is movable within the housing in the direction of the longitudinal axis. Furthermore, the electromagnetic stroke measurement system has a magnet holder and a sensor element, the magnet holder having magnets arranged in magnet sections, wherein the magnet holder is arranged on the radial periphery of the push rod about the longitudinal axis, such that the magnet holder is movable together with the push rod in the axial direction, and the sensor element is arranged about the longitudinal axis on the side of the housing opposite to the push rod. The housing is configured with a guide portion in which the magnet sections are guided at least partially in the direction of the longitudinal axis.

[0008] Since the magnet support moves axially with the push rod about its longitudinal axis, the position of the magnet corresponds to the position of the push rod. Therefore, guiding at least a section of the magnet in the guide portion of the housing can substantially directly correspond to the push rod movement in the stroke direction or the corresponding push rod position. Here, by guiding the magnet section, possible relative movement of the rest of the magnet support in spatial directions different from the axial direction can be compensated for or at least the effects of said relative movement can be reduced. Although this is not always explicitly stated, in the following text, the terms used to describe directions, such as radial or axial, refer to the longitudinal axis of the push rod.

[0009] Therefore, the magnet section can be directly guided or the magnet in that section can be received, thereby improving measurement accuracy or reducing measurement unreliability. The magnet section can also be constructed directly using magnets.

[0010] Hall sensors or magnetoresistive sensors can be used as sensor elements, generating a sensor signal corresponding to a change in the magnetic field, for example, by changing the resistance in the sensor element. Examples of magnetoresistive sensors are primarily GMR sensors, AMR sensors, or TMR sensors. In the case of Hall sensors based on the Hall principle, the so-called Hall voltage is measured, which changes due to a change in the magnetic field. This principle is based on the Hall effect, which occurs in an electrical conductor through which current flows. Magnetoresistive sensors, on the other hand, are based on changing the resistance in a thin ferromagnetic alloy using an external magnetic field. In this context, the planar Hall effect is generally known; however, this planar Hall effect only exhibits effects similar to the common Hall effect described above.

[0011] According to one extended scheme, the guide portion surrounds the guided magnet segment at at least three points in the circumferential direction, and in particular, completely surrounds it.

[0012] Therefore, the guided magnet segment is circumferentially surrounded by the guide portion about the longitudinal axis during its axial movement. Since the magnet segment is surrounded by the guide portion at at least three points in the circumferential direction, it is sufficiently guided. This prevents the magnet segment from moving radially about the longitudinal axis. These at least three points are spaced, for example, at 120° intervals in the circumferential direction. In other words, the guide portion completely surrounds the guided magnet segment in the circumferential direction. The term "completely" means that the guide portion completely surrounds the guided magnet segment to provide full circumferential guidance. Here, the guide portion may also have an interruption, but the interruption does not affect the guiding performance. In other words, the interruption prevents or does not increase the radial movement clearance of the guided magnet segment within the guide portion. In this context, the term "fully" refers to a guide surface that is fully circumferentially closed. For sensor elements arranged opposite the housing, the comprehensive construction of the guide portion protects the sensor element. Therefore, the sensor element is further separated from the movable parts by the housing through the comprehensive guide portion. Therefore, it is necessary to prevent moisture and / or impurities from entering the space where the sensor elements are arranged.

[0013] In one configuration, the guide is arranged such that the magnet segment is movable between a first position and a second position in the direction of the longitudinal axis, in the first position at least one end of the magnet segment facing the guide is engaged in the guide, and in the second position the magnet segment is further guided into the guide.

[0014] Therefore, the magnet segment is guided at least sectionally along the entire path between the first and second positions in the direction along the longitudinal axis by the guide. Preferably, the first and second positions form the maximum stroke of the magnet support corresponding to the maximum stroke of the push rod. Accordingly, the magnet segment can move via the guide throughout its entire movement in the direction along the longitudinal axis.

[0015] If the magnet segment engages only with the guide in the first position and extends further into the guide only as it moves to the second position, the magnet segment can be more easily mounted on the pushrod and installed in the electromagnetic stroke measurement system. In particular, the guide can thus also be configured in the second position as a simple movement limiter for the magnet holder, as will be described below. Therefore, the first position can correspond to either the assembly position or the initial position.

[0016] In one configuration, the magnet support has a retaining section that extends radially about the longitudinal axis and is received in a recess provided in the push rod for this purpose.

[0017] Therefore, the retaining section is as follows: this section extends radially from the magnet section in the direction of the push rod. In order to arrange the magnet support on the periphery of the push rod, the free end of the retaining section, that is, the end that is radially away from the magnet section, is received in a recess provided in the push rod for this purpose, so that it can move together with the push rod in the axial direction.

[0018] In particular, the recess is constructed as a groove that radially surrounds the longitudinal axis, especially a groove that surrounds the entire perimeter.

[0019] The term "radially circumferential groove" refers to a groove that extends at least sectionally along the periphery of the pushrod. Multiple radially circumferential grooves can also be formed, arranged in the direction of the longitudinal axis, and / or arranged radially circumferentially, i.e., at the same height about the longitudinal axis. This creates the possibility of setting up a modular structure so that, for example, pushrods for different stroke measurement systems with different positional requirements for the magnet holder can be implemented, and / or multiple magnet holders can be used. In the case of a fully circumferential groove, the groove is radially circumferential without interruption, allowing arbitrary receiving positions to be selected along the periphery of the pushrod for the holding section and therefore for the magnet holder. Here, multiple fully circumferentially circumferential grooves can also be arranged spaced apart from each other in the axial direction.

[0020] Alternatively, the recess may have other geometric configurations that correspond to the free end of the retaining section so that the free end can be received.

[0021] Preferably, the recess can be designed to be wider in the circumferential direction than the area of ​​the retaining section to be received in the recess. For example, if the recess of the push rod is formed by a groove that surrounds the entire circumference in the radial direction, relative movement between the retaining section or the magnet holder and the push rod can be achieved over the entire circumference of the push rod. Even if the push rod rotates about its longitudinal axis in the housing, the magnet holder can remain held in the push rod and in the guide, and the rotation of the push rod is not transmitted to the magnet holder. Furthermore, the corresponding configuration does not require additional lateral guides to prevent radial torsion of the magnet holder on the housing or the cover of the housing, thus enabling a low-wear configuration.

[0022] According to one extended scheme, the section is supported axially without clearance about the longitudinal axis in the recess.

[0023] Therefore, the axial movement of the pushrod corresponds to the axial movement of the magnet support. Furthermore, the magnet support is prevented from tilting about an axis perpendicular to the longitudinal axis by providing a backlash-free support in the axial direction.

[0024] The axially clear support is configured in particular to prevent the retaining section from moving in the recess in the circumferential and / or radial directions (if this is predetermined) or to prevent such movement from causing excessive wear or material load.

[0025] According to one extension, the magnet support is pre-tensioned axially about the longitudinal axis by a spring elastic element, which is preferably arranged in the guide between the end of the magnet section facing the guide and the end of the guide opposite to that end.

[0026] By pre-tensioning, the retaining section can be pressed against one of the opposing sidewalls of the recess, thereby achieving axially gapless support of the retaining section within the recess. For this purpose, the spring element is constructed, for example, as a compression spring, which is arranged in the guide. Here, the compression spring is supported by one end on the end of the magnet section facing the guide, and by the other end on the bottom of the guide opposite the magnet section. The guide may also have one or more radially inwardly pointing protrusions that serve as supports instead of the bottom of the guide. The compression spring then presses the retaining section against the sidewall of the opposing sidewall of the recess that is away from the guide. Alternatively, the spring element can also be constructed as a tension spring. In this case, the tension spring pulls the retaining section against the sidewall of the opposing sidewall of the recess facing the guide. For this purpose, the tension spring is correspondingly anchored at its support point. Whether the spring elastic element is configured to apply pressure or tension, the spring elastic element is particularly configured such that it applies prestress throughout the entire predetermined movement of the magnet support or push rod in the direction of the longitudinal axis.

[0027] In particular, the section is supported in the recess with a gap in the radial direction about the longitudinal axis.

[0028] By utilizing the gap in the radial direction, relative movement between the region receiving the pushrod in the recess of the retaining section and the pushrod can be achieved in the radial direction. This prevents or at least reduces the influence of the radial movement of the pushrod on the radial position of the magnet support.

[0029] In one configuration, the push rod has a central axis extending along a longitudinal axis, wherein the sensor surface of the sensor element facing the housing is arranged parallel to a sensor plane that extends parallel to the central axis, and a guide is arranged facing the sensor surface. Here, the sensor element is arranged outside a plane formed by a perpendicular line from the central axis to the sensor plane and the central axis itself.

[0030] Therefore, the sensor plane is such that the sensor surface of the sensor element facing the housing is oriented parallel to this plane. Here, in the radial direction, either in or parallel to the sensor plane, the sensor element is not located on a perpendicular line relative to the central axis of the pushrod, but is laterally offset from this perpendicular line. Therefore, according to the above configuration, the guide portion facing the sensor element or sensor surface is also outside this perpendicular line in this respect. Therefore, the housing with the guide portion can be closer to the sensor plane because the structural space for the guide portion is offset at an angle from almost the perpendicular line. Therefore, the stroke measurement system can be constructed more compactly.

[0031] According to one extended embodiment, the tappet is guided in the direction of the longitudinal axis within the tappet guide.

[0032] Here, the pushrod guide can be constructed as a cover for the housing, eliminating the need for additional components to guide the pushrod. The pushrod guide can be made of, for example, plastic. Preferably, the pushrod guide is arranged opposite the guide opening for the magnet holder in the direction of the pushrod's longitudinal axis. Therefore, the magnet holder moves axially between the pushrod guide and the end of the magnet holder's guide facing away from the guide opening. The pushrod guide can have a stop for the pushrod constructed on its axially facing side towards the guide opening, thereby restricting the pushrod's movement toward the pushrod guide. For this purpose, the pushrod, for example, has a pushrod guide section configured to guide the pushrod within the pushrod guide, the diameter of which is smaller than the diameter of a region of the pushrod that can abut against the stop formed by the pushrod guide. The stop position of the pushrod on the pushrod guide can, for example, correspond to the first position already mentioned.

[0033] In particular, the pushrod is pre-tensioned about the longitudinal axis in the axial direction by a spring elastic element, preferably pre-tensioned in the direction of the pushrod guide.

[0034] The push rod can be held in a predetermined initial position by a spring-loaded elastic element. For example, the spring-loaded elastic element pretensions the push rod in the direction of the previously described push rod guide, so that the push rod can remain in contact with, for example, a stop formed by the push rod guide without the application of any additional force. For this purpose, the spring-loaded elastic element can be constructed as a compression spring arranged in the push rod and supported against a support surface that is axially opposite the push rod guide. Alternatively, the spring can also be externally guided around the push rod, such that the push rod is arranged within a spring coil.

[0035] On the other hand, the present invention relates to a magnet holder for an electromagnetic travel measurement system according to the invention, the magnet holder having a magnet, wherein the holding section of the magnet holder is constructed as a cantilever, and the magnet section extends at an angle to the cantilever, in particular substantially perpendicularly.

[0036] Therefore, the magnet support is L-shaped, with one side having a holding section as a cantilever and the other side forming the magnet section. By arranging these sides substantially perpendicular to each other, the magnet section can be guided parallel to the longitudinal axis and the sensor element in the recess of the pushrod, with the holding section receiving it perpendicularly. This parallel movement allows the guide portion of the magnet section to be configured with largely small tolerances. Here, the substantially perpendicular arrangement of these sides relative to each other addresses possible manufacturing tolerances that could lead to minor deviations.

[0037] In one configuration, the retaining section has two retaining arms at its free end, the two retaining arms extending laterally outward on both sides of the retaining section in the plane of the retaining section, from which the magnet section extends, and the two retaining arms are particularly curved in the direction of extension and away from the direction of the magnet section.

[0038] By using retaining arms, the area in the recess of the retaining section for receiving the pushrod, as described above, can be increased without needing to increase the overall size of the retaining section. Depending on the given retaining conditions, such as weight, leverage, or the like, the size of the retaining arms can be determined to be sufficiently large. To balance the area of ​​the retaining section held in the recess, the retaining arms are preferably constructed symmetrically to each other. By the curved shape of the retaining arms, wherein the curved ends of the retaining arms point away from the magnet section, the retaining arms can, for example, mimic the shape of a groove as a recess for receiving the retaining arms. Therefore, the retaining arms can have the largest possible support surface in the axial direction without creating an interfering profile. Furthermore, the retaining arms can also be used to secure the magnet holder in the recess of the pushrod during assembly.

[0039] According to one extension, the face of the retaining arm is at least partially bulging, the face extending substantially parallel to the plane of the retaining section, from which the magnet section extends.

[0040] By means of the bulging construction of the surface, the retaining arm can accommodate rotation of the strut about an axis extending perpendicular to the longitudinal axis. In this context, the term "substantially parallel" means that the bulging surface does not strictly extend parallel to a plane. Accordingly, the term refers to surface orientation. Regarding the aforementioned fixation during assembly, the bulging configuration of the retaining arm further provides the possibility of implementing compensating movements during the assembly process.

[0041] In another aspect, the present invention also relates to the application of an electromagnetic travel measurement system according to the invention in a foot brake module.

[0042] The advantages of the corresponding application are derived in a similar manner to those of the previous embodiments. In particular, the application of the electromagnetic travel measurement system according to the invention for foot brake modules can improve safety through more reliable travel measurement, and is therefore particularly advantageous for safety-related applications. Attached Figure Description

[0043] The invention will now be described in more detail with reference to the accompanying drawings. The drawings specifically illustrate: Figure 1 A schematic cross-sectional view of an electromagnetic travel measurement system according to an exemplary embodiment, in a section along the longitudinal axis. Figure 2 according to Figure 1A schematic cross-sectional view of the electromagnetic stroke measurement system along line AA; Figure 3 The travel measurement system is based on Figure 1 A schematic cross-sectional view of an enlarged portion of the area of ​​the magnet holder. Detailed Implementation

[0044] Figure 1 A schematic cross-sectional view of an electromagnetic stroke measuring system according to an exemplary embodiment is shown in a section along the longitudinal axis (L). The stroke measuring system has a push rod 5, wherein the longitudinal axis L points in the direction of the stroke movement of the push rod 5. The push rod 5 is arranged in a housing 1. The housing 1 receives the push rod 5 and surrounds the push rod with a radial periphery about the longitudinal axis L. The axial end of the push rod 5 is guided in the axial direction in a push rod guide 6. Therefore, the push rod 5 can move in a guided manner in the axial direction. The push rod guide 6 here constitutes a cover for the housing 1. Here, the stroke of the push rod 5 in the direction of the push rod guide 6 is limited by a stop formed by the push rod guide 6. For this purpose, the push rod 5 has a shoulder between the section that should move in the push rod guide 6 and the section that further extends into the housing 1. This shoulder can be constructed by a radially outwardly pointing protrusion or by a general increase in the cross-sectional area of ​​the push rod 5. In the exemplary embodiment shown, the push rod 5 is a column with two sections, each with a different diameter. The push rod section with the smaller diameter guides the push rod 5 within the push rod guide 6. A shoulder is formed by the push rod section with the larger diameter engaging with the smaller diameter section, which then interacts with the stop of the push rod guide 6. The abutment of the push rod 5 on the stop of the push rod guide 6 corresponds to a first position of the push rod 5 and therefore to a first position of the magnet holder 3, which will also be described below.

[0045] The push rod 5 is pre-tensioned toward the push rod guide 6 by a spring elastic element 9, which is a compression spring. For this purpose, the spring elastic element is arranged in an internal space formed within the push rod 5, which is open on a side away from the push rod guide 6 along the longitudinal axis L. Here, the spring elastic element 9 is supported in the longitudinal axis direction on the inner side of the push rod facing the push rod guide and on a support surface opposite to this inner side, which is not shown here. Alternatively, the spring elastic element may also be arranged around the push rod 5 and supported on a protrusion on the push rod 5 pointing radially outward about the longitudinal axis L. Alternatively or supplementarily, multiple spring elastic elements may be provided.

[0046] In order to measure the stroke of the push rod 5, a sensor element 2 is arranged on the radial side of the housing 1 away from the push rod 5. The sensor element 2 is arranged on a circuit board 8, which is fastened to the housing 1 via a sensor element cover 7. In the example shown, the sensor element 2 is thus located in the space formed by the housing 1 and the sensor element cover 7, and is therefore protected from external influences.

[0047] Sensor element 2 detects the strength of the magnetic field of magnet 4. Here, the strength of the magnetic field detected by sensor element 2 varies depending on the relative position of magnet 4 with respect to sensor element 2. For stroke measurement, magnet 4 can only move in the axial direction to avoid distortion of the measurement signal due to changes in the distance from sensor element 2 in other spatial directions. Here, the axial movement of magnet 4 corresponds to the movement of push rod 5 in that direction. For this purpose, magnet 4 is arranged in the magnet section 3a of magnet bracket 3.

[0048] However, according to an alternative implementation, the magnet may also directly constitute the magnet segment or constitute at least one exposed portion of the magnet segment.

[0049] The magnet support 3 is received in the groove 5a of the push rod 5 via the area of ​​the retaining section 3b. Here, the groove 5a is constructed as a groove that radially surrounds the entire circumference. By arranging the retaining section 3b at least partially in the groove 5a, the magnet support 3 moves together with the push rod 5 in the event of axial movement. The area of ​​the retaining section 3b received in the groove 5a is supported in the groove 5a without clearance in the axial direction.

[0050] The retaining section 3b of the magnet bracket 3 forms a cantilever that extends radially outward from the slot 5a about the longitudinal axis L, i.e., radially towards the housing 1 from the perspective of the push rod. The magnet section 3a extends axially from the end of the retaining section 3b that is radially away from the push rod 5. Here, the extension of the magnet section 3a points away from the push rod guide 6 from the retaining section 3b, pointing downward in the image plane. Therefore, the magnet bracket 3 is constructed as an L-shape, wherein these sides form a 90° angle.

[0051] Given that the magnet segment 3 and therefore the magnet 4, as described above, move largely only in the axial direction, the magnet segment 3a moves in a guided manner in the axial direction within the guide portion 1a. The guide portion 1a is formed by the housing 1 and constitutes a guide channel. A portion of the guide portion 1a is formed by the outer wall of the housing 1, wherein the guide channel is closed in the circumferential direction by an inner wall segment. Therefore, the magnet segment 3a guided in the guide portion 1a is completely and comprehensively surrounded in the radial circumferential direction within the guide portion 1a in the guided region. Here, the guide portion 1a is configured such that the radial sidewalls of the guide portion 1a surround the region of the magnet segment 3a guided within the guide portion substantially without gaps. This substantially gapless configuration prevents the magnet segment 3a from moving in the guide portion 1a in a spatial direction different from the axial direction. However, axial movement is also possible simultaneously. The term "substantially" in this context means that, given and / or the required measurement accuracy, a small movement in a spatial direction different from the axial direction is tolerable.

[0052] The guide portion 1a of the magnet segment 3a has a guide opening facing the push rod guide portion 6 in the axial direction. This guide opening is used to receive the magnet segment 3a. In a first position, the magnet segment 3a engages with the guide opening and thus with the guide portion 1a by means of its free end facing away from the holding segment 3b in the axial direction. In this first position, the push rod 5 rests against a stop formed by the push rod guide portion 6. If the push rod now moves axially into the housing 1 against the spring force of the spring elastic element 9, the magnet support 3 moves together in the same direction. Thus, the magnet segment 3a is further guided into the guide portion 1a. An edge is constructed in the region of the guide opening by the inner wall section of the guide portion 1a. The magnet support 3 is movable axially between the first position and a second position, in which the magnet segment is further guided into the guide portion 1a. Therefore, the magnet segment 3a is guided past the sensor element 2 in a positionally reliable manner by the guide portion 1a, which is oriented parallel to the sensor element 2 in the axial direction.

[0053] Furthermore, a spring elastic element 1b is arranged in the guide portion 1a between the end of the magnet section 3a facing the guide portion 1a and the end of the guide portion 1a opposite to that end. Here, the spring elastic element is constructed as a compression spring. The spring force of the spring elastic element acts in the direction of the longitudinal axis L. The compression spring pretensions the magnet support 3 in the axial direction toward the push rod guide portion 6. Correspondingly, the retaining section 3b is pressed in the groove 5a against the side wall facing the push rod guide portion 6, which extends in the radial direction about the longitudinal axis. Therefore, the retaining section 3b can be retained in the groove 5a without clearance in the axial direction.

[0054] refer to Figure 2 The arrangement of the free end of section 3b in the slot 5a of the pushrod will be described in more detail below. Figure 2 Showing according to Figure 1 A schematic cross-sectional view of the electromagnetic stroke measurement system along line AA.

[0055] According to the cross-sectional view along line AA, the retaining section 3b has two retaining arms 3c at its free end, which is radially away from the magnet section 3b. The retaining arms 3c extend from the magnet section 3a toward the free end of the retaining section in a plane parallel to the extending direction of the retaining section 3b on both sides of the retaining section. The extending direction of the retaining section 3b corresponds to the radial direction in its arrangement on the periphery of the push rod 5. The retaining arms are curved in a plane parallel to the extending direction of the retaining section 3b, wherein the free end of the retaining arm 3c points away from the magnet section 3a through the bend. In other words, the retaining arm is constructed with a convex arc about the magnet section 3a and a concave arc about the push rod 5. Here, the radius of the arc formed by the retaining arm 3c substantially corresponds to the radius of the groove 5a. Here, the width of the retaining arm 3c in the plane parallel to the extending direction of the retaining section 3b is slightly smaller than the groove depth of the groove 5a in the radial direction. Due to this smaller width, radial relative movement between the retaining arm 3c and the push rod 5 is possible. However, the width of the retaining arm is at least large enough that the retaining arm 3c will not move out of the slot 5a in the radial direction under maximum relative movement. This radial clearance, combined with the magnet section 3a being received in the guide 1a, prevents or at least reduces the effect of radial movement of the push rod 5 on the magnet support.

[0056] According to the groove 5a that surrounds the entire radial circumference, the magnet support 3 can also move relative to the push rod 5 in the circumferential direction. Therefore, the effects of torsion of the push rod 5 about its longitudinal axis L can also be prevented. Therefore, no additional lateral guide is needed to prevent torsion of the magnet support 3 on the housing or on the push rod guide 6 or cover, thus minimizing wear.

[0057] In addition, according to Figure 2The cross-sectional view shows the arrangement of the guide portion 1a of the magnet section 3a with respect to the sensor element 2. Here, the guide portion 1a of the magnet section 3a is formed by a radially outwardly pointing housing protrusion of the housing 1. The sensor element 2 has a sensor surface facing the housing 1, which is oriented parallel to the sensor plane 2a, which extends parallel to the central axis 5b of the push rod 5 (which corresponds here to the longitudinal axis L of the push rod 5). Here, the sensor surface facing the housing 1 is arranged relative to the guide portion 1a of the magnet section 3a. Here, the arrangement of the sensor element 2 or the sensor surface relative to the guide portion 1a is located outside a plane formed by the perpendicular line 5c from the central axis 5b to the sensor plane 2a and the central axis 5b. In other words, the housing protrusion constituting the guide portion 1a has an angular offset from the perpendicular line falling radially through the central axis onto the sensor plane. As a result, the housing 1 can be moved closer to the sensor element 2, enabling a more compact construction. This can also be achieved by having the guide portion 1a have only radial housing protrusions and therefore only have radially enlarged cross-sections in sections.

[0058] Figure 3 The travel measurement system is shown in accordance with Figure 1 A schematic cross-sectional view of an enlarged portion of the magnet support area. This enlarged cross-sectional view shows the bulging construction of the face of the retaining arm 3c, which extends substantially parallel to the plane of the retaining section 3b from which the magnet section 3a extends. The bulging construction of the face allows the retaining arm 3c to accept rotation of the push rod about an axis extending perpendicular to the longitudinal axis. Therefore, the effect of torsion of the push rod 5 about an axis perpendicular to the longitudinal axis L on the magnet support 3 is also prevented or at least reduced. Conversely, as shown here, slight tilting of the magnet section 3a in the guide portion 1a can also be compensated. Here, the bulging of the face is configured as a face extending in the radial direction, i.e., arranged in one spatial direction. In an alternative embodiment, the bulge can be arranged in two spatial directions, i.e., for example, a bulge can also be arranged on the axially extending face of the retaining section 3b facing the bottom of the groove 5a. The bulge results in a convex construction of the corresponding face.

[0059] For the purpose of explanation, Figure 3The slight tilt of the magnet holder 3, as shown in the diagram, is exaggerated. As previously described, the radial sidewalls of the guide portion 1a surround the area of ​​the magnet segment 3a that is guided within the guide portion with virtually no clearance. This clearancelessness is also achieved here by the spring elastic element 1b within the guide portion 1a. Here, a point of rotation for the entire magnet holder 3 is also present by maintaining the arm 3c in contact with the groove 5a. By the spring force, the magnet holder 3 is pressed against the inner wall of the guide portion 1a at two opposing points, thereby achieving "clearancelessness" in the assembled state and therefore also in operation.

[0060] This invention is not limited to the described embodiments. In particular, features described with respect to embodiments of the invention, configurations described in other ways, and extensions can be combined with each other if the features are not reasonably mutually exclusive.

[0061] List of reference numerals 1. Shell 1a Guiding Section 1b Spring elastic element (guide part) 2. Sensor Components 2a Sensor plane 3. Magnet support 3a Magnet Section 3b Maintaining Section 3C retaining arm 4 magnets 5 tappets 5a slot 5b Central axis 5c perpendicular line 6. Tappet Guide Section 7 Sensor element cover 8 circuit boards 9. Spring elastic element (taper)

Claims

1. An electromagnetic stroke measurement system, wherein the electromagnetic stroke measurement system comprises: Tappet (5), said tappet having a longitudinal axis (L) pointing in the direction of travel, wherein, The push rod (5) is arranged in the housing (1) in the direction of the longitudinal axis (L) and is able to move in the housing in the direction of the longitudinal axis (L); A magnet bracket (3) having magnets (4) arranged in a magnet section (3a) of the magnet bracket (3), wherein the magnet bracket (3) is arranged on the radial periphery of the push rod (5) about the longitudinal axis (L), such that the magnet bracket can move together with the push rod (5) in the axial direction; and Sensor element (2), the sensor element being arranged about the longitudinal axis (L) on the side of the housing (1) opposite to the push rod (5), The housing (1) includes a guide section (1a) in which the magnet segment (3a) is guided at least segmentally in the direction of the longitudinal axis (L). The magnet bracket (3) has a retaining section (3b) that extends radially about the longitudinal axis (L) and is received in a recess provided in the push rod (5) for this purpose, wherein the retaining section (3b) is supported in the recess with a gap about the longitudinal axis (L) in the radial direction.

2. The electromagnetic stroke measurement system according to claim 1, wherein, The guide (1a) surrounds the guided magnet segment (3a) at at least three points in the circumferential direction.

3. The electromagnetic stroke measurement system according to claim 1 or 2, wherein, The guide (1a) is configured such that the magnet segment (3a) is movable between a first position and a second position in the direction of the longitudinal axis (L), in the first position at least one end of the magnet segment (3a) facing the guide (1a) is engaged in the guide (1a), and in the second position the magnet segment (3a) is further guided into the guide (1a).

4. The electromagnetic stroke measurement system according to claim 1 or 2, wherein, The recess is constructed as a groove (5a) that radially surrounds the longitudinal axis (L).

5. The electromagnetic stroke measurement system according to claim 1 or 2, wherein, The retaining section (3b) is axially supported in the recess without clearance about the longitudinal axis (L).

6. The electromagnetic stroke measurement system according to claim 5, wherein, The magnet bracket (3) is pre-tensioned in the axial direction about the longitudinal axis (L) by a spring elastic element (1b).

7. The electromagnetic stroke measurement system according to claim 1 or 2, wherein, The push rod (5) has a central axis (5b) extending along the longitudinal axis (L), and wherein the sensor surface of the sensor element (2) facing the housing (1) is arranged parallel to the sensor plane (2a), which extends parallel to the central axis (5b), and the guide (1a) is arranged facing the sensor surface, wherein the sensor element (2) is arranged outside the plane formed by the perpendicular line (5c) from the central axis (5b) to the sensor plane (2a) and the central axis (5b).

8. The electromagnetic stroke measurement system according to claim 1 or 2, wherein, The push rod (5) is guided in the direction of the longitudinal axis (L) in the push rod guide (6).

9. The electromagnetic stroke measurement system according to claim 1 or 2, wherein, The push rod (5) is pre-tensioned in the axial direction about the longitudinal axis (L) by a spring elastic element (9).

10. The electromagnetic stroke measurement system according to claim 2, wherein, The guide portion (1a) completely surrounds the guided magnet segment (3a) in the circumferential direction.

11. The electromagnetic stroke measurement system according to claim 4, wherein, The recessed structure is a groove that surrounds the entire perimeter.

12. The electromagnetic stroke measurement system according to claim 6, wherein, The spring elastic element is arranged in the guide (1a) between the end of the magnet section (3a) facing the guide (1a) and the end of the guide (1a) opposite to that end.

13. The electromagnetic stroke measurement system according to claim 8, wherein, The push rod (5) is pre-tensioned in the axial direction about the longitudinal axis (L) by a spring elastic element (9), and the push rod (5) is pre-tensioned in the direction of the push rod guide (6).

14. A magnet holder (3) for an electromagnetic stroke measuring system according to any one of claims 1 to 13, the magnet holder having a magnet (4), wherein, The holding section (3b) of the magnet support (3) is constructed as a cantilever, and the magnet section (3a) extends at an angle to the cantilever.

15. The magnet holder (3) according to claim 14, wherein, The retaining section (3b) has two retaining arms (3c) at its free end, the two retaining arms extending laterally outward on both sides of the retaining section (3b) in the plane of the retaining section (3b), from which the magnet section (3a) extends.

16. The magnet holder (3) according to claim 15, wherein, The face of the retaining arm (3c) is at least partially bulging, and the face extends substantially parallel to the plane of the retaining section (3b), from which the magnet section (3a) extends.

17. The magnet holder (3) according to claim 14, wherein, The magnet section (3a) extends substantially perpendicular to the cantilever.

18. The magnet holder (3) according to claim 15, wherein, The two retaining arms are bent in the extending direction and point away from the magnet section (3a).

19. An electromagnetic travel measurement system according to any one of claims 1 to 13 for use in a foot brake module.

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