Sensor assembly

Abstract

Sensor assembly, in particular for a hydraulic or machine system, with a sensor electronics cable connection device comprising a housing, a sealing and cable fixing plug adapted to an open front side of the housing, a section of a supply cable with its ends stripped and extending through an opening in the sealing and cable fixing plug into the housing and passing through the housing, and a screw terminal device forming part of the sealing and cable fixing plug, which serves to fix the end of the supply cable in the housing closed with the sealing and cable fixing plug, wherein the closure and cable fixing plug has, in addition to the opening for the supply cable, at least two further openings which are opposite one another, in particular with respect to the supply cable opening, or are preferably evenly distributed over the circumference of the supply cable opening, and wherein the interior of the housing and the closure and cable fixing plug around the end section of the supply cable and the screw terminal device are filled with a cured sealing compound which also seals the other openings.

Description

[0001] The invention relates to a sensor assembly, in particular for a hydraulic or machine system, with a sensor electronics cable connection device. Such a sensor electronics cable connection device comprises a housing, a sealing and cable fixing plug adapted to an open end of the housing, and a section of a supply cable with stripped ends that extends into the housing through an opening in the sealing and cable fixing plug and passes through the housing.

[0002] It further relates to a method for producing such a sensor assembly.

[0003] The sensor assembly may in particular be a position sensor assembly of a hydraulic or machine system comprising at least one position sensor of the magnetostrictive type, in which the position sensor detects the position of a magnet axially displaceable on a waveguide cladding tube with respect to a waveguide axially arranged in the waveguide cladding tube.

[0004] In principle, however, it can also be a sensor assembly for other purposes, provided that it includes a sensor electronics cable connection device that has the basic structure outlined above.

[0005] If there is sufficient space for the sensors, designs of the sensor electronics cable connection device are generally used. These include a cover (also referred to here as a sealing and cable fixing plug), a profile sealing element or an O-ring seal, and, for cable entry, rely on conventional cable glands or plug contacts, among other options. A conventional cable gland requires two different seals: one to seal against the housing, usually an O-ring, and a special seal to seal the cable against the gland body. In total, a standard sensor therefore has at least three seals in the cover alone (profile seal for the cover, sealing insert for the cable, and an O-ring to seal the cable gland to the cover).

[0006] A profile seal is not a standardized seal, but rather a component specifically designed for the sensor's geometry. Manufacturing these seals requires relatively expensive tools.

[0007] A sensor assembly of the type in question here has two end faces to which a cover including a sealing element must be attached, one of which also has a cable feedthrough.

[0008] The task of developing an ultra-flat sensor raises the question of a suitable cable entry and a correspondingly compact cover or plug that seals the sensor to meet the necessary IP requirements. The assembly of the conventional solution involves several steps, making installation relatively complex. Given the above-mentioned task, the sensor's overall height must not be unnecessarily increased by a standardized cable gland.

[0009] Covers are located at both the front and rear ends of the sensor, ensuring the housing's tightness against external influences. Based on the sensor size in relation to the individual components, one can already guess how compact the covers are, with their functionality for cable routing, grounding, and sealing.

[0010] The detailed design of the lids with integrated sealing function is described below. This demonstrates how the lid also significantly improves efficiency and workflows in assembly processes.

[0011] According to the invention, the closure and cable fixing plug has, in addition to the opening for the supply cable, at least two further openings which are located opposite one another, in particular with respect to the supply cable opening, or are preferably evenly distributed over the circumference of the supply cable opening, and wherein the interior of the housing and the closure and cable fixing plug around the end section of the supply cable and the screw terminal device are filled with a hardened sealing compound which also seals the further openings.

[0012] According to the above explanations, the housing is substantially flat cuboid-shaped and, correspondingly, the closure and cable fixing plug has a cover section with a rectangular cross-section and the supply cable opening is preferably arranged centrally (or near the center) in the closure and cable fixing plug, and two further openings are arranged, substantially opposite each other with respect to the supply cable opening, near the short sides of the rectangular end section.

[0013] More specifically, the width / height ratio of the housing and the closure and cable fixing plug is greater than 2.5, and the housing of the sensor electronics cable connection device is formed integrally with a housing of the sensor assembly.

[0014] In a currently preferred embodiment, the end of the supply cable located in the housing is stripped in two stages to expose a shielding conductor braid arranged in the cable sheath in a first stripped section and individual conductors arranged inside the supply cable in a second stripped section. The screw terminal device is designed to secure the first stripped section with a cable clamp bridge and simultaneously connect the exposed conductor braid to earth or ground. The cured sealing compound also serves as an insulating compound.

[0015] Specifically, the sealant is intended to be a moisture-curing, thixotropic 1-component sealant based on silane-modified polymers.

[0016] From a method perspective, the invention is defined as a method for producing a sensor electronics cable termination device of the sensor assembly, in particular for a hydraulic or machine system, comprising the following steps: providing a housing, providing a closure and cable fixing plug adapted to an open end face of the housing, which closure and cable fixing plug has an opening for passing through a supply cable and two further openings opposite one another with respect to the supply cable opening or preferably evenly distributed over its circumference, and which has a screw terminal device for fixing the end of the supply cable, providing a supply cable with its insulation stripped at its end, inserting the stripped end of the supply cable through the opening in the closure and cable fixing plug, fixing the end of the supply cable in the closure and cable fixing plug by actuating the screw terminal device,Inserting the sealing and cable fixing plug with the end of the supply cable fixed therein into the open end of the housing, injecting a liquid or pasty sealing compound into one of the other openings to fill the housing and the sealing and cable fixing plug until liquid sealing compound emerges from the or one of the other openings in the sealing and cable fixing plug, and allowing the sealing compound to harden in the assembled housing.

[0017] One embodiment of the method is characterized in that the housing is essentially cuboid-shaped and, correspondingly, the sealing and cable fixing plug has a cover section with a rectangular cross-section. Here, the supply cable opening is preferably located centrally in the sealing and cable fixing plug, and two additional openings are provided near the short sides of the rectangular end section, essentially opposite each other with respect to the supply cable opening. The liquid or pasty sealing compound is injected using a dispenser, the end of which is inserted into one of the two additional openings.

[0018] In a further preferred embodiment, the end of the supply cable located in the housing is stripped in two stages to expose a shielding conductor braid arranged in the cable sheath in a first stripped section and individual conductors arranged inside the supply cable in a second stripped section. The screw terminal device is actuated to secure the first stripped section with a cable clamp bridge and simultaneously connect the exposed conductor braid to earth or ground. In this case, the sealing compound, in particular, is also an insulating compound.

[0019] Advantages and usefulness of the invention will become apparent from the following description of an embodiment with reference to the figures. These show: Fig. 1A and Fig. 1B Perspective views of an exemplary sensor assembly in the closed and largely open state, Fig. 2 an illustration of the sealant sealing of the cable connection end of the sensor assembly and Fig. 3 a detailed view of the sensor electronics cable connection device with an attached sealant dispenser.

[0020] Fig. 1A shows a perspective view of a sensor assembly 1 housed in a flat, cuboid-shaped, one-piece housing 2. The housing 2 is closed at a first end with a closure and cable fixing plug 3, through which a connecting cable 4 is guided into the sensor assembly 1, and at the opposite end with a cover 5.

[0021] As in Fig. As can be seen in Figure 1B, the housing 2 of the sensor assembly 1 houses a complex sensor electronics unit 6, which is electrically connected by the connecting cable 4. The connecting cable 4 enters a sensor electronics cable connection device 7, in which it is secured as a whole by means of a screw terminal device 8. It can be seen that the housing 2 of the sensor assembly here also forms a housing for the sensor electronics cable connection device 7.

[0022] Fig. 2 shows a step essential to the invention in the manufacture of the sensor assembly 1, namely the filling and sealing of the sensor electronics cable connection device 7 inserted into the housing 2 and thus of the connection end of the sensor assembly.

[0023] A sealing and cable fixing plug 3 of the sensor electronics cable connection device 7 (see in detail Fig. 3) has, in addition to a central, larger opening 3a for the passage of the connecting cable 4, two small openings 3b and 3c on either side of that opening. A sealant dispenser 9 is attached to the opening 3c, by means of which viscous or pasty sealing or insulating compound is pressed through the opening 3c into the interior of the sealing and cable fixing plug. As soon as sealant begins to emerge from the other small opening 3d, the interior of the sensor electronics cable connection device 7 is completely filled with sealant, and the injection process is terminated.

[0024] Fig. 3 shows details of the sensor electronics cable connection device 7 and the end of the connection cable 4.

[0025] The connecting cable 4 is prepared for the external connection of the sensor electronics 6 by stripping its end in two stages, first (by removing the outer cable sheath) to expose an outer shielding braid—not shown in the figure—and then individual conductors not specifically labeled. The connecting cable 4 prepared in this way is inserted through the central opening 3a of the sealing and cable fixing plug 3 until its externally stripped section reaches the area of ​​the screw terminal device 8, while the individual conductors extend sufficiently far into the installation space of the sensor electronics so that they can be connected to the corresponding components there.

[0026] The end section of the supply cable 4, freed from the outer cable sheath, is fixed by tightening the screws of the screw terminal device 8 and at the same time earthed or connected to ground. Subsequently, the sealing and cable fixing plug 3 is inserted into the housing 2 (see Fig. 2) introduced.

[0027] Due to the appropriate design of the closure and cable fixing plug 3 and the screw terminal device 8, as well as the suitable relative position of the opening 3c, the sealant injected through the small opening 3c is directed in such a way that the sealant flows through the entire sensor electronics cable connection device 7 and fills all of its cavities, displacing the air previously located there. Finally, the sealant reaches the opening 3b and begins to flow out of it. This signals that the injection process can be terminated.

[0028] The embodiment of the invention is not limited to the example described here, but is also possible in a multitude of modifications and other applications within the scope of expert practice. In particular, it is also possible for sensors with a similar external design but different operating principles, and the sensor electronics cable connection device can have a different geometry and modified opening configurations.

Claims

[1] Sensor assembly, in particular for a hydraulic or machine system, with a sensor electronics cable connection device comprising a housing, a sealing and cable fixing plug adapted to an open front side of the housing, a section of a supply cable with its ends stripped and extending through an opening in the sealing and cable fixing plug into the housing and passing through the housing, and a screw terminal device forming part of the sealing and cable fixing plug, which serves to fix the end of the supply cable in the housing closed with the sealing and cable fixing plug, wherein the closure and cable fixing plug has, in addition to the opening for the supply cable, at least two further openings which are opposite one another, in particular with respect to the supply cable opening, or are preferably evenly distributed over the circumference of the supply cable opening, and wherein the interior of the housing and the closure and cable fixing plug around the end section of the supply cable and the screw terminal device are filled with a cured sealing compound which also seals the other openings. [2] Sensor assembly according to claim 1, wherein the housing is substantially flat cuboid-shaped and, corresponding thereto, the closure and cable fixing plug has a cover section with a rectangular cross-section and wherein the supply cable opening is arranged in or near the center in the closure and cable fixing plug and two further openings, in particular opposite one another with respect to the supply cable opening, are arranged near the short sides of the rectangular end section. [3] Sensor assembly according to claim 1 or 2, wherein the width / height ratio of the housing and the closure and cable fixing plug is greater than 2.

5. [4] Sensor assembly according to one of the preceding claims, wherein the housing of the sensor electronics cable connection device is formed integrally with a housing of the sensor assembly. [5] Sensor assembly according to one of the preceding claims, wherein the end of the supply cable arranged in the housing is stripped in two stages in order to expose, in a first stripped section, a shielding conductor braid arranged in the cable sheath and, in a second stripped section, individual conductors arranged in the interior of the supply cable, wherein the screw terminal device is designed to fix the first stripped section with a cable clamp bridge and at the same time to connect the conductor braid exposed there to earth or ground, and The cured sealant also acts as an insulating compound. [6] Sensor assembly according to one of the preceding claims, wherein the sealing compound comprises a moisture-curing, thixotropic 1-component sealant based on silane-modified polymers.

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