Determining the rotational position of a wave

Abstract

The invention relates to an arrangement for determining the rotational position of a shaft (8) with at least one magnet (21) arranged on or in the shaft (8) and a magnetic field sensor (23) arranged adjacent to the shaft (8) so that the magnetic field of the magnet (21) can be detected, characterized in that the pole axis P of the magnet (21) is inclined relative to the axis of rotation L of the shaft (8) by an angle α. This makes it possible to design such an arrangement more compactly. The invention further relates to a switch (4,5) with such an arrangement and a waste container receptacle (1), in particular for a waste collection vehicle, with such a switch (4,5).

Description

[0001] The invention relates to an arrangement for determining the rotational position of a shaft with a magnet arranged on or in the shaft and a magnetic field sensor arranged adjacent to the shaft so that the magnetic field of the magnet can be detected.

[0002] Determining the position of shafts or axes of rotation in general is of great importance in kinematic arrangements. For example, an event can be triggered as soon as a shaft reaches a certain position. Or it is necessary to know the exact rotational position of a shaft in order to precisely execute the movements of an automated system.

[0003] For this purpose, it is known from the prior art to determine the rotational position of a shaft using an angle encoder. For this purpose, a magnet is arranged on the shaft, whose magnetic field is detected by a suitable sensor. When the shaft rotates, the magnetic field changes, which can be detected by a sensor. To ensure optimal rotation detection, the magnet is often arranged at the end of the shaft and the sensor is opposite the end. This requires more space in the axial direction of the shaft. Furthermore, if the arrangement is used outdoors, for example in a commercial vehicle, there is a risk of the sensor becoming contaminated.

[0004] The object of the present invention is to compensate for these disadvantages. This object is achieved by an arrangement having the features of patent claim 1 and, in particular, by a switch having the features of patent claim 6 and a waste container holder having the features of patent claim 8. Particular embodiments of the invention are the subject of the respective dependent claims.

[0005] The invention relates to an arrangement for determining the rotational position of a shaft with at least one magnet arranged on or in the shaft and a magnetic field sensor arranged adjacent to the shaft so that the magnetic field of the magnet can be detected, wherein the pole axis of the magnet is inclined by an angle α with respect to the rotational axis of the shaft.

[0006] Due to the inclination of the magnet's polar axis relative to the shaft's axis of rotation, its magnetic field is tilted relative to the shaft. This means that even at a point adjacent to the shaft's outer surface, the local magnetic flux density changes significantly over the course of one rotation of the shaft, so that a specific value of the magnetic field strength correlates with a rotational position of the shaft. This is not possible with a magnet aligned parallel to the axis of rotation. This means that it is no longer necessary for the magnet and sensor to be arranged at the end of the shaft. Instead, the magnet and sensor can be arranged at any position along the shaft's length, making optimal use of the available space and making the entire arrangement more compact.At the same time, the sensor can be better protected from contamination, for example by placing it under the shaft and thus no longer being exposed to precipitation and dust, which impair the measurement.

[0007] A single magnet can be used, but two, three, or more individual magnets can also be combined, with their polar axes preferably coinciding. This makes it possible to optimally design the magnet depending on the intended use of the invention and adapted to the structural conditions.

[0008] Preferably, components located near the magnet(s) are made of a non-metallic material, such as stainless steel, plastic, or brass. These materials are not magnetized even by the presence of the magnet(s), which would distort the measurement results of the magnetic field sensor. The shaft, in particular, is made of a non-magnetic material.

[0009] In one embodiment of the invention, the angle α is in the range of 30° to 60°, preferably in a range of 35° to 55°, particularly preferably in a range of 40° to 50°.

[0010] In another particular embodiment of the invention, the magnetic field sensor is inclined with its detection axis at an angle β in a range of 60° to 120°, preferably in a range of 80° to 100°, relative to the rotational axis of the shaft. This enables a compact design and, on the other hand, makes it possible to obtain a highly sensitive detection signal, since a varying measurement signal is generated depending on the position of the sensor, which is usually based on the Hall effect. This, together with the inclination of the magnet, enables a more precise determination of the rotational position of the shaft.

[0011] Furthermore, the rotation of the shaft is preferably limited to an angular range of no more than 90°. The magnetic field strength of a rotating magnet exhibits a periodicity, which results in multiple rotational positions associated with the same magnetic field strength, depending on the configuration. Limiting the rotation of the shaft ensures that a rotational position of the shaft can be determined unambiguously.

[0012] Preferably, an evaluation unit is provided to assign a rotational position of the shaft to a detected value of the magnetic flux density. The correlated value pairs can be fed directly to the evaluation unit or stored in a memory to which the evaluation unit has access. The evaluation unit can be coupled to a controller or be part of a controller that executes process or method steps dependent on the rotational position of the shaft.

[0013] The invention also relates to a switch with a previously described arrangement for determining the rotational position of a shaft. Switching operations are particularly important in commercial vehicles. When the switch is actuated, the shaft is moved, which is detected by the sensor. The magnitude of the angular range covered, for example, allows conclusions to be drawn about the applied force. Or, it can be provided that a process step is triggered as soon as a rotation by a minimum angle has occurred. This requires precise detection of the rotational position of the shaft. Such a switch is also very compact and can be used in many applications.

[0014] Preferably, a lever is coupled to the shaft, serving as the actuating element for the switch. The lever can be shaped to suit the application, ensuring optimal force is always applied when the switch is actuated. Furthermore, the switch can be designed to require as little installation space as possible.

[0015] The invention further relates to a waste container holder, in particular for a waste collection vehicle, with a switch as described above. A waste container holder is provided so that a waste container, such as a garbage can, is arranged thereon and is emptied into a waste collection area. For this purpose, a mechanism is provided which lifts and / or tilts the waste container. An emptying cycle should only take place when the waste container is correctly positioned on the waste container holder. Furthermore, during the lifting and / or tilting process, a check should be made to ensure that the waste container is held securely on the waste container holder. For this purpose, switches are provided which are located in an inherently dirty environment. Whether and, if so, how strongly a switch has been actuated by the positioned waste container is read from the rotational position of the switch shaft.To ensure the proper functioning of the waste container holder, it is therefore necessary that the rotational position of the shaft be determined reliably and precisely. At the same time, the installation space is extremely limited. A waste container holder according to the invention has a compact switch, since the arrangement for determining the rotational position of a shaft requires little space. At the same time, the risk of contamination is greatly reduced.

[0016] Preferably, the switch is located below and / or within a tooth of the waste container holder. The teeth of a waste container holder engage with corresponding pockets of a waste container to pick up and lift the waste container. This means that the waste container comes into direct contact with the waste container holder at the teeth. Proper positioning of the waste container on the waste container holder can best be checked at these locations. If the switch is located below a tooth, improved protection against contamination is also provided because the tooth additionally shields the entire assembly.

[0017] The switch can be a proximity switch, which is activated when a waste container is pushed toward the waste container receptacle. This signals the waste container receptacle control system that a waste container has been correctly positioned and positioned, allowing the emptying cycle to begin.

[0018] The switch can also be a so-called acknowledgement switch, which is activated when a waste container has been correctly picked up from the waste container holder. This prevents the waste container from falling off the waste container holder during the emptying process. The control system continues the emptying cycle. If the acknowledgement switch is not activated or not activated as intended during the lifting and / or tipping process, the emptying cycle is aborted.

[0019] Further possible applications of an arrangement according to the invention can be, for example, a tilting or lifting-tilting mechanism for emptying a waste container, in particular for a waste collection vehicle.

[0020] They show: Fig. 1 a waste container holder with switches with an arrangement according to the invention, Fig. 2 a switch with an arrangement according to the invention, Fig. 3 a switch in exploded view, Fig. 4 a switch in sectional view.

[0021] The waste container holder 1, which is in Fig. 1, has a comb 2 with several teeth 3. Some of the teeth 3 are designed as proximity switches 4 or acknowledgement switches 5. Such waste container receptacles 1 are usually arranged on waste collection vehicles.

[0022] When a waste container is pushed toward the waste container holder 1, one or more proximity switches 4 are activated, depending on the container size. This provides a control system (not shown here) with confirmation that a waste container is ready, so that an emptying cycle can be started.

[0023] The waste container holder 1 is then moved upwards so that the teeth 3 engage with corresponding pockets of the waste container, thereby lifting the waste container. Preferably, two acknowledgement switches 5 are activated, as this ensures that the waste container is securely suspended from the waste container holder 1.

[0024] Once both switch signals have been received, the control system performs the emptying cycle, tilting the waste container and emptying it into a collection container. For this purpose, a tilting shaft 6 is provided on the waste container holder 1, which rotates the entire waste container holder 1. The waste container is additionally supported by a support 7.

[0025] It is also possible to equip the tilting shaft 6 with an arrangement according to the invention for determining the rotational position of the tilting shaft 6.

[0026] The Fig. 2 to 4 show a proximity switch 4 with an arrangement for determining the rotational position of a shaft 8. The proximity switch 4 is arranged below or within a tooth 3 of the waste container holder 1.

[0027] Tooth 3 has the shape of an inverted U. In the installed position, a first leg 10 and a second leg 11 extend downwards from the tip 9 of tooth 3.

[0028] The first leg 10 has a first opening 12. The second leg 11 has a second opening 13. The openings 12, 13 are aligned with each other. Within them, the shaft 8 is mounted on plastic bearings 14, 15 for rotation about its longitudinal axis L.

[0029] A lever 16 is screw-connected to the shaft 8 by a screw 17 and a nut 18. When a waste container is pushed toward the waste container holder 1, the container exerts a force on the lever 16, causing the shaft 8 to rotate about its longitudinal axis L, which is also the axis of rotation.

[0030] The rotational position of the shaft 8 thus provides the information as to whether the proximity switch 4 has been actuated to such an extent that it can be assumed that the waste container is positioned so close to the waste container holder 1 that it can be picked up cleanly by the latter.

[0031] In order to ensure that the lever 16 is returned to its original position after the emptying cycle has been completed and the waste container has been removed, a spring element 19 is provided, which here is designed as a spiral spring arranged on a plastic ring 20.

[0032] To determine the rotational position of the shaft 8, three cylindrical magnets 21 are arranged immovably and rotationally fixed in the shaft 8, so that when the shaft 8 rotates about its longitudinal axis L, it rotates with the shaft 8. The polar axes of the magnets 21 coincide and they generate a common magnetic field.

[0033] The magnetic field of the magnets 21 rotates accordingly around the longitudinal axis L. The magnets 21 are arranged such that the pole axis P is inclined relative to the longitudinal axis L of the shaft 8 by an angle α of 45°.

[0034] The second leg 11 of tooth 3 has a bore 22. The bore 22 extends from the free end of the second leg 11 to the second opening 13. A magnetic field sensor 23 is arranged in this bore 22, which detects the local magnetic field strength of the magnets 21 rotating with the shaft 8. The magnetic field sensor 23 is secured in the bore 23 by a grub screw 24.

[0035] Due to the inclination of the polar axis P relative to the longitudinal axis L, the magnetic field strength at the detection point of the magnetic field sensor 23 varies greatly during rotation, so that the rotational position of the magnets 21 and thus of the shaft 8 can be precisely assigned to a specific magnetic field strength.

[0036] This offers the advantage that the magnetic field sensor 23 can be arranged very variably on the shaft 8. This allows for better use of the available installation space and a very compact design. The magnets 21 can be positioned longitudinally along the shaft to suit the available installation space, and the magnetic field sensor 23 can also be arranged at the appropriate location in the longitudinal direction and at the appropriate angle β relative to the shaft 8.

[0037] In the present example, the detection axis D of the magnetic field sensor 23 is inclined by an angle β of 90° relative to the longitudinal axis L of the shaft 1. Depending on the available installation space, the inclination could also be 80° or 100°, for example.

[0038] The sensitivity of the measurement can also be improved by the inclination of the magnetic field sensor 23 by adjusting this positioning to the arrangement of the magnets 21.

[0039] The shaft 8 itself, as well as the components arranged on it and the tooth 3, are made of non-magnetic stainless steel. As a result, these components are not magnetized by the presence of the magnets 21, which would distort the detection by the magnetic field sensor 23 due to the additional and unpredictable magnetic field.

[0040] For the same reason, the plastic bearings 14 and 15 are made of a non-magnetic material. Alternatively, they could also be made of a metallic material such as brass.

[0041] In the illustrated embodiment, the available space is optimally utilized by arranging the arrangement according to the invention below or within the tooth 3. The available space between the teeth 3 of the waste container holder 1 is limited, since it must be ensured that the teeth 3 engage in the corresponding pockets of the waste containers without the walls of the pockets colliding with the switch arrangement, particularly with the magnetic field sensor 23, which would result in the waste container no longer sitting correctly on the teeth 3 or in damage to the switch arrangement.

[0042] Furthermore, the assembly is better protected against contamination. In particular, the arrangement of the magnetic field sensor 23 within tooth 3 means that the magnetic field sensor 23 is no longer affected by dirt or splashing water. Likewise, the operability of the switching mechanism, i.e., shaft 8 with lever 16 and spring 19, is ensured, as it is protected, in particular, from waste particles that may fall from the waste container or waste collection chamber.

[0043] This ensures the repeatability of the switching process and the safety of the operating personnel. Reference symbol 1 waste container holder 2 comb 3 tooth 4 proximity switches 5 acknowledgment switches 6 tilt shaft 7th edition 8 Wave 9 top of 3 10 first leg of 3 11 second leg of 3 12 first breakthrough 13 second breakthrough 14 plastic bearings 15 plastic bearings 16 levers 17 Screw 18 mother 19 spring 20 plastic rings 21 Magnet 22 Hole 23 Magnetic field sensor 24 grub screw D Detection axis of 23 L Longitudinal axis of 8 P polar axis of 21 α angle β angle

Claims

[1] Arrangement for determining the rotational position of a shaft (8) with at least one magnet (21) arranged on or in the shaft (8) and a magnetic field sensor (23) arranged adjacent to the shaft (8) so that the magnetic field of the magnet (21) can be detected, characterized by that the pole axis P of the magnet (21) is inclined by an angle α relative to the rotation axis L of the shaft (8). [2] Arrangement according to claim 1 characterized by that the angle α is in the range of 30° to 60°, preferably in a range of 35° to 55°, particularly preferably in a range of 40° to 50°. [3] Arrangement according to claim 1 or 2 characterized by that the magnetic field sensor (23) is inclined with its detection axis D by an angle β in a range of 60° to 120°, preferably in a range of 80° to 100°, relative to the rotational axis L of the shaft (8). [4] Arrangement according to at least one of the preceding claims characterized bythat the rotation of the shaft (8) is limited to an angular range of maximum 90°. [5] Arrangement according to at least one of the preceding claims characterized by that an evaluation unit is provided to assign a rotational position of the shaft (8) to a detected value of the magnetic flux density. [6] Switch (4,5) with an arrangement according to at least one of the preceding claims. [7] Switch (4,5) according to claim 6 characterized by that a lever (16) is coupled to the shaft (8). [8] Waste container holder (1), in particular for a waste collection vehicle, with a switch (4, 5) according to claim 6 or 7. [9] Waste container holder (1) according to claim 8 characterized by that the switch (4,5) is arranged below and / or within a tooth (3) of the waste container holder (1).

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