Measuring system with integrated sensor unit

Abstract

The protected component is a measuring wheel assembly comprising a measuring wheel (21), a support arm (8), a circuit board (25) integrated into the support arm, a circuit board holder (26) in the housing (29), a magnetic ring (27) which is pressed onto the shaft (24) parallel to the circuit board, ball bearings (28), a cover cap (22) and a corresponding cable design with strain relief (23).

Description

State of the art measuring wheel system with rotary encoder

[0001] Measuring wheels can be used to detect linear or rotary movements, in particular to determine distance, speed, position, or feed rate in any moving system. They are used in a wide variety of industrial and logistical applications, such as for precise distance and feed rate measurement in conveyor and sorting systems, packaging and printing machines, production and assembly lines, labeling and cutting systems, battery and film manufacturing, robot and test benches, textile and composite plants, recycling and sorting lines, warehouse and order picking robots, and in automated guided vehicles (AGVs / AMRs).

[0002] The existing setup of a measurement system is in Fig. 1a and Fig. 1b shown.

[0003] The measuring wheel (1) has a disc-shaped wheel body (2). This typically transitions radially outwards into an annular running surface (3), which projects beyond the disc-shaped wheel body (2) in a direction parallel to the geometric central axis of the measuring wheel. Towards the geometric central axis of the measuring wheel, the disc-shaped wheel body (2) transitions into a cylindrical hub body (4) with a central bore coaxial to the geometric central axis of the measuring wheel, which projects beyond the annular running surface (3) in at least one direction.The shaft (6) of a rotary encoder (7) is inserted into this central bore and is connected to the hub body (4) and thus to the measuring wheel (1) in a rotationally fixed manner by means of hub screws (5), so that the running movement of the measuring wheel (1) leads directly to a rotational movement of the shaft (6) of the rotary encoder (7), which is measured by the rotary encoder (7) and converted into the length of the distance traveled by the wheel using the geometric data of the measuring wheel.

[0004] The measuring wheel (1) is supported by the shaft (6) of the rotary encoder (7). The assembly consisting of the rotary encoder (7) and measuring wheel (1) is attached to a support structure located in the Fig. 1a and Fig. 1b, formed by a support arm 8 which is resiliently mounted in a spring bearing (9), is achieved via the housing of the rotary encoder (7), which is usually arranged on the side of the support arm (8) opposite the measuring wheel (1). Because the cylindrical hub body (4) projects beyond the annular running surface (1) in at least one direction, this arrangement ensures that the annular running surface (2) does not rub against the support arm (8).

[0005] A disadvantage of the known measuring wheel arrangements is that this configuration entails a relatively high installation space requirement in the direction parallel to the geometric central axis of the measuring wheel. Description

[0006] The object of the invention is to provide a more compact measuring wheel arrangement. This object is achieved by a measuring wheel arrangement with the features of claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

[0007] Fig. 2a / Fig. 2b: The measuring wheel arrangement according to the invention comprises a measuring wheel (21), a support arm (8), a circuit board (25) integrated into the support arm, a circuit board holder (26) screwed into the housing (29), a magnetic ring (27) which is pressed onto the shaft (24) parallel to the circuit board, ball bearings (28), a cover cap (22) and a corresponding cable design with strain relief (23).

[0008] This arrangement integrates the state-of-the-art rotary encoder into the support arm, eliminating the installation space required for it.

[0009] By positioning the circuit board in its socket and in conjunction with the parallel magnetic ring directly on the support arm, with a required bearing built into the arm and the components placed under a cover cap which contains the second bearing, very good protection against mechanical damage can be achieved.

[0010] Stable mounting of the measuring wheel within the measuring wheel assembly is preferably achieved by providing the assembly with a rotatable, ball-bearing-mounted axle that supports both the measuring wheel and the magnetic ring. Since compensating elements are unnecessary, backlash-free transmission of the rotary motion from the measuring wheel to the sensor is ensured. The arrangement of the system with the circuit board and magnetic ring between the bearings guarantees the necessary stability and precise concentricity without lateral runout.

[0011] The design ensures that a quick and easy change of the spring direction and the required contact pressure is still possible.

[0012] Data is read via a cable that is protected from kinking by a dust- and dirt-resistant cable exit in the cover cap and is routed along the spring arm. In the prior art, the protruding cable at the rotary encoder is often problematic, as mechanical stress due to the 90-degree exit angle of the cable is very likely, potentially causing the connection to the encoder to break. In the new solution, the cable exits the cap at a 90-degree angle but is well protected by its positioning on the spring arm.

[0013] Due to the overall very narrow design of the measuring unit, the width of the support system is not exceeded, making it suitable for use in areas with limited installation space. The new measuring system's width is reduced by up to 45%, and its integration within the spring arm itself and sealing with a protective cap make the system less susceptible to contamination.

[0014] In our measuring system, the newly developed sensor unit is integrated directly into the spring arm. This system is insensitive to electrical impulses, as it is able to compensate for them against the measurement result. Therefore, results distorted by external influences (electrical impulses, magnetic fields, etc.) can be virtually eliminated. The choice of measuring wheel material has no effect on the measurement result.

[0015] The new system has a very high air gap tolerance, which is unique on the market. Shocks and vibrations are also no longer a problem – thanks to the lower weight and compact design, damage can be avoided.

Claims

[1] The purpose of the protection is to be a measuring wheel arrangement comprising a measuring wheel (21), a support arm (8), a circuit board (25) integrated into the support arm, a circuit board holder (26) in the housing (29), a magnetic ring (27) which is pressed onto the shaft (24) parallel to the circuit board, ball bearings (28), a cover cap (22) and a corresponding cable design with strain relief (23). [2] Also to be protected is a plug-and-play solution for the measuring wheel arrangement. Here, a recess is located in the arm (30), and the cable leading from the circuit board terminates in a provision for plugging a connector for reading the data directly onto the arm. This significantly reduces the length of the cable leading from the circuit board and ensures quick and easy handling of the system. [3] Another variant is to be protected, in which the measurement results are transmitted wirelessly. [4] The power supply to the circuit board is also to be protected by means of a coil which functions as a generator and generates an induced voltage with each rotation of the measuring wheel, which charges the battery (31) and powers the system. The coil is located in the area of ​​the encoder / measuring wheel assembly.

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