DE102020131658A1 - Method of attaching a sensor element to a rotatable component for an actuator - Google Patents

Abstract

The invention relates to a method for fastening a sensor element to a rotatable component for an actuator by means of a hold-down device and an arrangement with a support element, a sensor element to be fastened and a hold-down device. In the method, the rotatable component has a depression that extends around an axis of rotation of the component. The hold down has an energy director protruding from a surface of the hold down. The method includes arranging the sensor element in the recess on the rotatable component and placing the hold-down device on the rotatable component. The hold-down device is placed in such a way that the energy director is at least partially arranged in a gap between the sensor element and a side wall of the recess and comes into contact with the rotatable component and the sensor element. The method further includes performing a welding operation to attach the sensor element to the rotatable component using the hold-down device.

Description

AREA

The present invention relates to a method for fastening a sensor element to a rotatable component for an actuator by means of a hold-down device and an arrangement with a support element, a sensor element to be fastened and a hold-down device.

BACKGROUND

Small electric motors such as brushless direct current motors (BLDC motors) are used, among other things, in the automotive sector and in automation technology, for example as servomotors, fan motors or drives for positioning actuators such as flap actuators or valves, for example needle valves. In such actuators, sensor elements often have to be attached to rotatable components such as gear wheels. For example, a magnet can be arranged on a driven wheel of an actuator in order to determine the position of the driven wheel using a Hall sensor based on the magnetic field generated by the magnet, for example to determine the position of an actuator coupled to the driven wheel.

In order to attach the magnet to the output gear, it can be overmoulded using an injection molding process or glued to the output gear. However, the materials used to manufacture such magnets are often very brittle. This means there is a high risk that the magnet will be damaged if it is directly overmoulded or glued. In addition, attachment by gluing, for example, can be impractical in automated series production.

OVERVIEW

It is therefore an object of the invention to provide a method for attaching a magnet to a rotatable component of an actuator, in which the risk of damaging the magnet when carrying out the method is reduced.

According to the invention, this object is achieved by a method having the features of claim 1 and an arrangement having the features of claim 10 . Developments of the invention are specified in the dependent claims.

A method is provided for attaching a sensor element to a rotatable component for an actuator using a hold-down device. The rotatable component has a recess that extends around an axis of rotation of the component. The hold down has an energy director protruding from a surface of the hold down. The method includes arranging the sensor element in the recess on the rotatable component and placing the hold-down device on the rotatable component. The hold-down device is placed in such a way that the energy director is at least partially arranged in a gap between the sensor element and a side wall of the recess and comes into contact with the rotatable component and the sensor element. The method further includes performing a welding operation to attach the sensor element to the rotatable component via the hold-down.

In some embodiments, the rotatable component, the sensor element to be fastened and the hold-down device can correspond to the carrying element, the sensor element to be fastened and the hold-down device of the arrangement according to the invention described below. The rotatable component can be a gear wheel of an actuator, for example. The sensor element to be attached can be, for example, a magnet that is used to determine the position of the rotatable component.

The recess can be adapted to the shape of the sensor element to be fastened in terms of its lateral dimensions and/or its height profile. One or more lateral dimensions of the depression are larger than corresponding dimensions of the sensor element to be fastened, so that the sensor element to be fastened is spaced apart from one or more side walls of the depression by a gap when it is arranged in the depression. The gap can extend completely or partially around the sensor element to be attached and have a width of between 0.1 mm and 2 mm, for example, between 0.2 mm and 1 mm in one example. In some configurations, the depression is arranged on the axis of rotation of the rotatable component, such that the axis of rotation extends through a bottom surface of the depression and the sensor element arranged thereon. In other examples, the indentation is annular and extends around the axis of rotation. For example, the bottom surface of the recess may extend perpendicularly to the axis of rotation, while one or more side walls of the recess may extend, for example, parallel to the axis of rotation.

The shape of the hold-down device is preferably also adapted to the shape of the depression and/or the sensor element to be fastened. In some embodiments, the shape of the hold-down device is selected such that the hold-down device placed on it extends along an edge of the sensor element to be fastened and/or an edge of the recess tion extends. The energy director is set up to melt completely or partially during the welding process. The welding process can include an ultrasonic welding process, for example, in which the energy director melts, for example due to the friction between the energy director and the rotatable component and/or the sensor element to be fastened. In a cross-section perpendicular to the surface of the hold-down, the energy director may have, for example, a tip or a tapered end face at its end remote from the surface of the hold-down. In some forms, the energy director has a triangular cross-sectional area. The energy director can also extend along an edge of the sensor element to be attached and/or an edge of the recess. In some examples, the energy director is a continuous ridge, which may, for example, run along a closed path, for example around a center point of the hold-down. In one example, the energy director extends along a circle, which may, for example, be concentric about the center point of the hold-down.

Arranging the sensor element to be fastened in the depression can include placing the sensor element on the bottom surface of the depression. The sensor element can be arranged partially or completely in the recess, for example so that a surface of the sensor element is flush with an upper edge of the recess or below the upper edge of the recess. In some embodiments, arranging the sensor element may also include adjusting a position and/or orientation of the sensor element. In one example, the sensor element is arranged in the recess in such a way that the center of gravity of the sensor element comes to rest on the axis of rotation. In another example, the sensor element is a magnet and the magnet is arranged in the recess such that an axis of magnetization of the magnet, i.e. the line connecting a north and a south pole of the magnet, has a predefined orientation relative to the axis of rotation and/or relative to the has rotatable component.

In some embodiments, placing the hold-down device can also include adjusting a position and/or orientation of the hold-down device, e.g. so that the center of gravity of the hold-down device lies on the axis of rotation and/or that the hold-down device has a predefined orientation relative to the axis of rotation, to the rotatable Component and / or has to the sensor element. When the hold-down device is placed on the rotatable component, the energy director is at least partially inserted into the gap between the sensor element to be fastened and the side wall of the recess, for example so that a tip of the energy director is arranged in the gap and the energy director is in contact with an upper edge of the side wall the recess and an edge of the sensor element to be attached.

The hold-down device is preferably placed on the rotatable component in such a way that areas of the surface of the hold-down device adjoining the energy director are at a distance from the rotatable component and/or the sensor element. In this way, a targeted transfer of energy to the energy director can be ensured and an over-definition of the arrangement of the hold-down device can be avoided. A region of the surface of the hold-down device which is opposite a surface of the rotatable component which adjoins the indentation can be spaced between 0.1 mm and 2 mm from this surface of the rotatable component, for example. Correspondingly, a region of the surface of the hold-down device that is opposite the sensor element to be fastened can be spaced, for example, between 0.1 mm and 2 mm from the corresponding surface of the sensor element to be fastened. One or both distances are preferably selected to be larger than a welding path of the welding process, so that the areas of the surface of the hold-down device adjoining the energy director are also spaced apart from the rotatable component and/or the sensor element after the welding process has been carried out. In some configurations, the entire surface of the hold-down, except for the energy director, is spaced from the rotatable member and/or the sensing element, in one example both before and after the welding operation is performed.

The energy director may have two opposing side surfaces, each inclined with respect to a normal vector of the surface of the hold-down. The two side surfaces of the energy director can, for example, each enclose an angle between 10° and 80°, in one example between 30° and 60°, with the normal vector of the surface of the hold-down device. The two side surfaces of the energy director can include the same or different angles with the normal vector of the surface of the hold-down device. In a preferred embodiment, the energy director has a triangular cross-section in which the side surfaces of the energy director converge at a tip remote from the surface of the hold-down, which tip may be rounded or flattened in some configurations.

The hold-down device can be placed on the rotatable component in such a way that one of the inclined side surfaces of the energy director comes into contact with an upper edge of the side wall of the recess or an edge of the sensor element, in particular an upper edge of the sensor element. The hold-down device is preferably placed on the rotatable component in such a way that the contact or support surface between the respective side surface of the energy director and the corresponding edge is approximately linear. In one example, after application of the hold-down device, the energy director extends circumferentially in whole or in part around the axis of rotation, with the radially inner side surface of the energy director being in contact with the edge of the sensor element and the radially outer side surface of the energy director being in contact with the top edge of the side wall.

In a preferred embodiment, the welding process produces an integral connection between the hold-down device and the rotatable component, for example by welding the energy director to the upper edge of the side wall of the recess. This can be achieved, for example, by selecting a suitable material, as described below in relation to the arrangement according to the invention. At the same time, the welding process can produce a form-fitting connection between the hold-down device and the sensor element, for example by at least partially melting the energy director without being welded to the edge of the sensor element. As a result, the sensor element can be fixed axially without play on the receiving surface without causing tension in the sensor element, which can lead to damage, particularly in the case of brittle material. In some configurations, the welding process can also produce an integral connection between the hold-down device and the sensor element.

In a preferred embodiment, the welding process includes an ultrasonic welding process. The ultrasonic welding process can be carried out by transmitting a high-frequency mechanical vibration to the hold-down device, the sensor element and/or the rotatable component. The frequency of the oscillation can be in the range between 10 kHz and 40 kHz, for example. The vibration can cause relative movement between the energy director and the corresponding contact or bearing surfaces on the rotatable component or sensor element. The resulting friction can lead to excessive heating, thereby melting all or part of the energy director and/or the bearing surfaces. In some embodiments, a positive and/or material connection between the energy director and the contact surfaces can be produced after cooling. In some configurations, an orientation of the rotatable component is selected during the welding process in such a way that the energy director and the bearing surfaces are pressed against one another by gravity. In some examples, external pressure may be applied to the hold-down, the sensing element, and/or the rotatable member during the welding process to urge the energy director and bearing surfaces together.

Alternatively or in addition to the ultrasonic welding process, the welding process can also be performed using other welding techniques, such as another friction or vibration welding technique, heat staking, heated tool welding and/or laser welding.

In some embodiments, the method also includes pressing the sensor element into the depression, so that the sensor element comes into contact with one or more centering elements arranged in the depression. As a result, the sensor element can be held in a predefined position in the depression, for example so that the sensor element is centered in the depression and/or relative to the axis of rotation. The centering elements can in particular be set up to hold the sensor element in the depression without radial play. The centering elements can be arranged, for example, on a side wall of the depression and/or on the bottom surface of the depression, for example as described below in relation to the arrangement according to the invention. The sensor element can, for example, be pressed into the recess in such a way that the sensor element is held in the recess in a non-positive and/or positive manner by the centering elements during the welding process.

Preferably, a first portion of the energy director is inserted into a gap between the sensor element and a first sidewall portion of the recess, and a second portion of the energy director is inserted into a gap between the sensor element and a second sidewall portion of the recess, opposite the first sidewall portion, to position the sensor element in the recess to center. In some configurations, the two gaps between the sensor element and the side wall sections of the indentation are sections of a continuous gap between the sensor element and the side wall, with the gap extending, for example, in the circumferential direction around the can extend entire sensor element. The first and second side wall sections can lie directly opposite one another and, for example, enclose an angle of between 170° and 190° with a center point of the depression and/or with the axis of rotation. In other examples, the first and second side wall sections can be offset opposite one another and enclose an angle of between 90° and 170°, in one example an angle of 120°, for example with the center point of the depression and/or with the axis of rotation.

In a preferred embodiment, a third section of the energy director is also inserted into a gap between the sensor element and a third side wall section of the recess, the first, the second and the third side wall section being offset by 120°, for example, around the center point of the recess and/or are arranged around the axis of rotation. In some examples, the energy director may be inserted along the entire perimeter of the sensing element into the gap between the sensing element and the sidewall of the cavity. The energy director may include a circumferential ridge protruding from the surface of the hold-down, or a plurality of spaced tabs each protruding from the first surface of the hold-down and may be arranged, for example, along a closed path.

In some configurations, the sensor element is a magnet, for example a dipole or quadrupole magnet. The magnet can, for example, be in the form of a ring, cylinder or disk and can be diametrically magnetized. The method may further include aligning an axis of magnetization of the magnet relative to the rotatable member. For example, the axis of magnetization of the magnet can be aligned when arranging the magnet in the recess such that the axis of magnetization runs perpendicular to the axis of rotation of the rotatable component. In addition, in some embodiments, the axis of magnetization can also be oriented such that the axis of magnetization runs parallel to a predetermined radial direction relative to the rotatable component.

To determine the position of the rotatable component, the magnet can interact with a magnetically sensitive sensor arrangement, in particular with a Hall sensor. The Hall sensor can be designed to detect one or more spatial components of the magnetic field. From the profile of the registered magnetic field strength, a rotational angle position of the rotatable component, for example a gear wheel, can thus be inferred. In particular, the Hall sensor can be arranged in the vicinity of the magnet on a printed circuit board. The printed circuit board can also include other electronic components, in particular a microcontroller for controlling an electric motor or actuator.

In a preferred embodiment, the rotatable component is a toothed wheel and in particular a driven wheel for an electric motor-driven actuator. The toothed wheel or output wheel can be set up, for example, to be mechanically coupled to a rotor of the electric motor, for example via a gear. In some configurations, the rotatable component can also be an intermediate wheel of the transmission, for example a reduction gear of an actuator driven by the electric motor. The output wheel can also be set up to be mechanically coupled to an actuator, and for this purpose can have, for example, an output shaft with a suitable carrier profile. In some configurations, the method can also include arranging the rotatable component in the actuator, for example arranging the toothed or driven wheel in a corresponding guide in a housing of the actuator and mechanically coupling it to the rotor of the electric motor.

The invention also provides an arrangement with a support element, a sensor element to be fastened and a hold-down device. The hold-down device is set up to be connected to the support element by ultrasonic welding in order to attach the sensor element to be fastened to the support element. The support element has a receiving surface which is set up to receive the sensor element to be fastened. The support member further includes an edge surface that extends along an edge of the receiving surface. The sensor element to be attached is spaced apart from the edge surface by a gap when the sensor element to be attached is arranged on the receiving surface. The hold-down has a first energy director protruding from a first surface of the hold-down. The first energy director is set up to be at least partially inserted into the gap between the sensor element to be fastened and the edge surface when the hold-down device is placed on the support element.

In some configurations, the support element can be a rotatable component for an actuator driven by an electric motor, which is set up to rotate about an axis of rotation, for example a toothed wheel or a driven wheel. Correspondingly, the support element can be similar or identical to the rotatable component used in the method according to the invention described above. The recording area can be, for example extend around the axis of rotation of the support member. The axis of rotation can be perpendicular to the receiving surface and, in some embodiments, can extend through the receiving surface. The edge surface can be inclined relative to the receiving surface and can extend, for example, perpendicularly to the receiving surface, for example parallel to the axis of rotation. In some embodiments, the support element can have a recess, for example on an end face of the support element, with the receiving surface being or comprising a bottom surface of the recess and one or more side walls of the recess or a part thereof forming the edge surface.

The dimensions of the receiving surface and the edge surface are selected in such a way that the sensor element to be fastened is spaced apart from the edge surface by a gap when the sensor element to be fastened is arranged on the receiving surface. For example, a dimension of the receiving surface can be larger than a dimension of the sensor element to be attached. For example, the receiving surface can have a width or a diameter along at least one direction that is greater than a width or a diameter of the sensor element to be attached, for example a width or a diameter of an underside of the sensor element to be attached resting on the receiving surface. Alternatively or additionally, the edge surface or part of it can be inclined relative to a side surface of the sensor element to be fastened or have a step, for example so that a lower part of the edge surface adjoining the receiving surface is in contact with the side surface of the sensor element to be fastened, while an upper Part of the edge surface is spaced apart by the gap from the side surface of the sensor element to be fastened. A width of the gap between the sensor element to be attached and the edge surface can be between 0.1 mm and 2 mm, for example, between 0.2 mm and 1 mm in one example. The gap between the edge surface and the sensor element to be fastened can extend along the entire circumference of the sensor element to be fastened or along part of it. In some embodiments, the gap can have a plurality of sections spaced apart from one another, which can be separated from one another, for example, by areas in which the sensor element to be fastened is in contact with the edge surface.

In some embodiments, the hold-down is similar or identical to that used in the method of the invention described above. The first energy director is set up to melt completely or partially during a welding process, in particular an ultrasonic welding process, e.g. due to the friction between the first energy director and a contact or bearing surface on the support element and/or on the sensor element to be attached. The first energy director may comprise, for example, an ultrasonically weldable metal and/or an ultrasonically weldable plastic, such as aluminum and/or a thermoplastic. The first energy director is arranged on the first surface of the hold-down device in such a way that its course fully or partially corresponds to the course of the gap between the sensor element to be fastened and the edge surface, for example so that the first energy director can be inserted into the gap along its entire length, when the hold-down device is placed on the support element.

The first energy director may be tapered from the first surface of the hold down toward an end of the first energy director opposite the first surface of the hold down. A width of the first energy director on the first surface of the hold-down device can be greater than a width of the gap between the sensor element to be attached and the edge surface, for example so that one or more side surfaces of the first energy director come into contact with an upper edge of the edge surface and/or an edge of the fixing sensor element come into contact when the tapered end of the first energy director is inserted into the gap.

The first energy director may have two opposing side surfaces each inclined with respect to a normal vector of the first surface of the blank holder. One of the inclined side surfaces can be in contact with the support element or the sensor element to be fixed when the first energy director is arranged in the gap between the sensor element to be fixed and the edge surface, e.g. as described above. The two side surfaces of the first energy director can, for example, each enclose an angle between 10° and 80°, in one example between 30° and 60°, with the normal vector of the surface of the hold-down device. The two side surfaces of the energy director can include the same or different angles with the normal vector of the surface of the hold-down device. In a preferred embodiment, the energy director has a triangular cross-section in which the side surfaces of the energy director converge at a tip remote from the surface of the hold-down, which tip may be rounded or flattened in some configurations.

The first energy director may include a circumferential ridge protruding from the first surface of the hold-down. The circumferential ridge may extend along a closed path on the first surface of the hold-down, such as along a circle, an ellipse, or a polygon. The circumferential web can extend around a center point of the hold-down device and, for example, run concentrically around the center point of the hold-down device. Alternatively or in addition to the circumferential ridge, the first energy director may include a plurality of spaced-apart tabs each projecting from the first surface of the hold-down. The lugs can also be arranged along a closed path on the first surface of the hold-down device, for example as described above, and for example each run along a section of the closed path. In one example, the first energy director includes between 3 and 20 tabs.

In some configurations, areas of the first surface of the hold-down device adjoining the first energy director are spaced apart from the support element and/or the sensor element to be fastened when the first energy director is arranged in the gap between the sensor element to be fastened and the edge surface. A region of the surface of the hold-down device, which is opposite a surface of the support element adjoining the edge surface, can be spaced between 0.1 mm and 2 mm from this surface of the support element, for example. Correspondingly, a region of the surface of the hold-down device that is opposite the sensor element to be fastened can be spaced, for example, between 0.1 mm and 2 mm from the corresponding surface of the sensor element to be fastened. The distance is preferably selected to be greater than a welding path for welding the hold-down device, so that the areas of the surface of the hold-down device adjoining the energy director are also spaced apart from the support element and/or the sensor element to be fastened after the welding process has been carried out. In some configurations, the entire surface of the hold-down, with the exception of the first energy director, is spaced apart from the support element and/or the sensor element to be attached, in one example both before and after the welding process is performed.

The first energy director and the support element, in particular a contact surface for the first energy director, for example the edge surface or at least the upper edge of the edge surface, preferably comprise materials that can be welded to one another by ultrasonic welding, e.g. in order to create a material connection between the hold-down device and the rotatable component. The first energy director and/or the hold-down device preferably comprise the same material or consist of the same material as the contact surface on the support element, e.g. a thermoplastic.

The sensor element to be fastened, on the other hand, can comprise a material that cannot be welded to the first energy director by ultrasonic welding, e.g. in order to produce a form-fitting connection between the hold-down device and the sensor element to be fastened. For example, a contact surface for the first energy director on the sensor element to be attached can comprise a metal and/or a plastic which has a higher melting point than the material of the first energy director. In other embodiments, the sensor element to be attached can also comprise a material which can be welded to the first energy director by ultrasonic welding, for example a thermoplastic material.

In some configurations, the hold-down device can have an opening and can be ring-shaped, for example. The first energy director can extend completely or partially around the opening. For example, the first energy director may extend along an inner or outer perimeter of the hold-down or at the center of the hold-down equidistant from the inner and outer perimeters of the hold-down. Furthermore, the hold-down device can have a collar on its inner and/or outer circumference, which protrudes from a surface of the hold-down device, in particular from a second surface of the hold-down device opposite the first surface. Such a shape can be advantageous, for example, for the manufacture of the hold-down device using an injection molding process.

The support element preferably has one or more centering elements which are set up to come into contact with the sensor element to be fastened when the sensor element to be fastened is arranged on the receiving surface. The centering elements can be set up, for example, to center the sensor element to be fastened on the receiving surface and/or relative to an axis of rotation of the support element. The centering elements can in particular be set up to hold the sensor element to be fastened on the receiving surface without radial play. The centering elements can, for example, each be a projection or a rib and on the receiving surface, the edge surface and/or a surface adjoining the receiving surface, for example another edge surface or sides wall, be arranged. In one example, the support element comprises a plurality of centering elements arranged along the edge of the receiving surface, for example a plurality of ribs protruding from an edge surface or side wall towards the receiving surface. In another example, a lower section of an edge surface or side wall adjoining the receiving surface is precisely adapted to the sensor element to be fastened, so that the sensor element to be fastened comes into contact with the lower section of the edge surface or side wall along its entire circumference when the fastening sensor element is arranged on the receiving surface.

In some embodiments, different areas of the hold-down have different thicknesses perpendicular to the first surface. For example, the hold-down may have different thicknesses in areas of the first surface that are on opposite sides of the first energy director. The hold-down device can, for example, have a greater thickness in a first area of the first surface, which adjoins a first side face of the first energy director, than in a second area of the first surface, which adjoins a second side face of the first energy director that is opposite the first side faces . The thickness of the hold-down device in the first area can be, for example, between 120% and 200% of the thickness of the hold-down device in the second area. In one example, the first energy director extends along a closed path and the portions of the hold-down that are inboard and outboard of the first energy director have different thicknesses. With such a design, the stability of the hold-down device can be increased and at the same time the hold-down device can be precisely adapted to the shape of the support element and/or the sensor element to be fastened, for example as described above.

In some embodiments, the hold-down device also has a second energy director, which is set up to come into contact with the sensor element to be fastened and/or the support element when the hold-down device is placed on the support element. The second energy director can also protrude from the first surface of the hold-down device and be set up, for example, to come into contact with a surface of the sensor element to be fastened, for example an upper side of the sensor element to be fastened, which is remote from the receiving surface, when the first energy director is in the Gap is arranged between the sensor element to be fixed and the edge surface. Alternatively, the second energy director can be configured to come into contact with a surface of the support element, for example a surface of the support element adjacent to the edge surface or a surface of a centering mandrel that is arranged in an opening of the sensor element to be fastened, e.g. as described below. The second energy director can be set up to be positively and/or materially connected to the sensor element to be fastened and/or the carrying element by welding. The second energy director is preferably made of the same material as the first energy director. Similar to the first energy director, the second energy director can also comprise a circumferential web and/or a multiplicity of lugs.

In some configurations, the first energy director extends around the second energy director. For example, the first energy director may be disposed along or adjacent an outer periphery of the hold-down, while the second energy director may be disposed in an inner region of the hold-down surrounded by the first energy director or along or adjacent an inner periphery of the hold-down. In one example, the first and second energy directors are concentric about a center point of the holddown.

In some embodiments, the arrangement includes an anti-twist device in order to arrange the sensor element to be fastened in a rotationally fixed manner on the receiving surface. The anti-twist device can, for example, comprise one or more securing elements on the hold-down device, which are each set up to engage with a corresponding counterpart on the sensor element to be fastened in order to arrange the sensor element to be fastened in a rotationally fixed manner on the receiving surface. Such a securing element can be, for example, a projection or a pin on the first surface of the hold-down device, which is set up to be inserted into a corresponding depression on the upper side of the sensor element to be fastened. Alternatively or additionally, a securing element can be, for example, a depression in the first surface of the hold-down device, which is set up to receive a corresponding projection or pin, which is arranged on the upper side of the sensor element to be fastened.

Alternatively or additionally, the anti-twist device can also include corresponding securing elements on the support element, for example on the receiving surface, the edge surface and/or a surface adjoining the receiving surface, for example a further edge surface or side wall. In one example, the sensor element to be fastened has one or more bulges or recesses on an inner or outer circumference, which are each set up to engage with a corresponding counterpart on an edge surface or side wall in order to rotate the sensor element to be fastened on the receiving surface to arrange. The sensor element to be fastened preferably has two opposing bulges or recesses.

In some configurations, the support element has a structure that protrudes from the receiving surface and is designed to be inserted into an opening in the sensor element to be fastened. The structure can be a centering mandrel, for example, onto which the sensor element to be fastened can be placed in order to arrange the sensor element to be fastened centrally on the receiving surface. The length of the centering mandrel can be selected such that the upper edge of the centering mandrel is flush with the top of the sensor element to be fastened when the sensor element to be fastened is arranged on the receiving surface. In other examples, the structure can be a shaft, in particular an output shaft, which extends through the opening in the sensor element to be fastened and can be set up, for example, to be mechanically coupled to an actuator. For this purpose, the output shaft can have a corresponding carrier profile on its outer circumference. In another example, the output shaft can be designed as a hollow shaft and have a corresponding carrier profile on its inner circumference.

In some embodiments, the sensor element to be fastened is arranged on the receiving surface and fastened to the support element by means of the hold-down device. The sensor element to be fastened can have been fastened to the support element, for example by means of the method according to the invention described above, for example by means of ultrasonic welding.

In a preferred embodiment, the support element is a rotatable component for an actuator. The support element can, for example, be a toothed wheel, in particular a driven wheel for an actuator. The sensor element to be attached is preferably a magnet, which can be used, for example, to determine the position of the rotatable component or an actuator coupled thereto. The magnet can be, for example, a dipole or quadrupole magnet and can be, for example, ring-, cylinder- or disc-shaped. The magnet is preferably diametrically magnetized. In particular, the magnet can be a rare earth magnet, for example a plastic-bonded neodymium-iron-boron magnet (NdFeB).

Furthermore, an actuator with an electric motor and an arrangement as described above is provided, with a printed circuit board being arranged in the actuator and the sensor element to be fastened being a magnet. A magnetic sensor for detecting a rotational angle position of the rotatable component is arranged on the printed circuit board in the vicinity of the magnet.

character list

• 1a: eine Anordnung mit einem Tragelement, einem zu befestigenden Sensorelement und einem Niederhalter gemäß einem Beispiel in Draufsicht;
• 1b: die Anordnung aus 1a im Querschnitt;
• 2a: eine Anordnung mit einem Abtriebsrad, einem zu befestigenden Magneten und einem Niederhalter gemäß einem Beispiel im Querschnitt;
• 2b: die Anordnung aus 2a in einer Explosionsdarstellung;
• 3: einen Stellenantrieb mit einem Elektromotor und mit der Anordnung aus 2a gemäß einem Beispiel im Querschnitt;
• 4a: eine Anordnung mit einem Abtriebsrad, einem daran befestigten zylindrischen Magneten und einem scheibenförmigen Niederhalter gemäß einem Beispiel im Querschnitt;
• 4b: die Anordnung aus 4a in einer perspektivischen Ansicht;
• 4c: eine vergrößerte Detailansicht der Anordnung aus 4a im Querschnitt;
• 5: einen Niederhalter gemäß einem Beispiel in einer perspektivischen Ansicht;
• 6: ein zu befestigendes Sensorelement mit einer Verdrehsicherung gemäß einem Beispiel in einer perspektivischen Ansicht;
• 7: eine Anordnung mit einem Abtriebsrad, einem daran befestigten ringförmigen Magneten und einem Niederhalter mit zwei Energierichtungsgebern gemäß einem Beispiel im Querschnitt; und
• 8: ein Flussdiagramm eines Verfahrens zum Befestigen eines Sensorelements an einem drehbaren Bauteil für einen Stellantrieb gemäß einem Beispiel.

The invention is explained in more detail below using exemplary embodiments with reference to the accompanying drawings. The figures show in a schematic representation:

• 1a 1: an arrangement with a support element, a sensor element to be fastened and a holding-down device according to an example in plan view;
• 1b : the arrangement off 1a in cross section;
• 2a 1: an arrangement with a driven wheel, a magnet to be fastened and a hold-down according to an example in cross section;
• 2 B : the arrangement off 2a in an exploded view;
• 3 : an actuator with an electric motor and with the arrangement 2a according to an example in cross section;
• 4a 1: an arrangement with a driven gear, a cylindrical magnet attached thereto and a disc-shaped hold-down according to an example in cross section;
• 4b : the arrangement off 4a in a perspective view;
• 4c : an enlarged detail view of the arrangement 4a in cross section;
• 5 : a hold-down according to an example in a perspective view;
• 6 1: a sensor element to be fastened with an anti-twist device according to an example in a perspective view;
• 7 1: an arrangement with an output wheel, an annular magnet fixed thereto and a hold-down with two energy directors according to an example in cross-section; and
• 8th : a flowchart of a method for attaching a sensor element a rotatable component for an actuator according to an example.

DESCRIPTION OF FIGURES

1a-1c show a schematic representation of an arrangement 100 according to the invention with a support element 102, a sensor element 108 to be fastened and a hold-down device 110 according to an example, wherein 1a shows the arrangement in plan view and 1b in cross section.

in the in 1a shown example, the support member 102 is a gear, for example, for use in an actuator with an electric motor. In other embodiments, the support element can be, for example, another component for an actuator operated by an electric motor, in particular a rotatable component such as a rotor, a shaft or an actuator mechanically coupled to the rotor.

The gear wheel 102 has a ring gear on its outer circumference and is set up to be rotated about an axis of rotation 104, for example by the gear wheel 102 being rotatably mounted in a corresponding bearing or guide of the actuator. For example, the gear 102 may have a diameter between 10 mm and 100 mm perpendicular to the axis of rotation 104, in one example a diameter between 20 mm and 50 mm. The toothed wheel 102 can, for example, be made of metal, e.g. steel and/or aluminum, and/or a hard plastic, in particular a glass fiber reinforced plastic, for example polyamide with a glass fiber content of between 20% and 40%. The gear wheel 102 can have been produced, for example, by means of a milling process, a casting process and/or an additive manufacturing process. In some configurations, the entire gear 102 is formed in one piece. In other examples, individual sensor elements may have been subsequently attached to gear wheel 102, e.g. glued to it. Gear 102 further includes a hollow cylindrical shaft 106 extending from an end face of gear 102 along axis of rotation 104 . The hollow shaft 106 can be configured to be mechanically coupled to another component, for example to another gear. In some embodiments, an inside or outside of the hollow shaft 106 has a drive profile, e.g., a polygonal drive profile such as an internal or external hexagon or another ring gear.

The arrangement 100 also includes a sensor element 108 to be fastened and a hold-down device 110 which is designed to be welded to the gear wheel 102 in order to fasten the sensor element 108 to be fastened to the gear wheel 102 . In the example of 1a , 1b the sensor element 108 to be fastened is a diametrically magnetized, disk-shaped magnet, for example a rare earth magnet, for example a pressed or injection-molded plastic-bonded neodymium-iron-boron magnet (NdFeB). The magnet 108 can be used, for example, in combination with a magnetic field sensor arranged in the actuator to determine a position of the gear wheel 102 .

The gear wheel 102 has a recess 112 on an end face opposite the hollow shaft 106 , which recess is designed to receive the magnet 108 . The recess 112 has a circular bottom or receiving surface 112A on which the magnet 108 is placed. The bottom surface 112A extends perpendicularly to the axis of rotation 104 which runs through the bottom surface 112A and the magnet 108 arranged in the recess 112 . The depth of the depression 112 is chosen such that a top side 108A of the magnet 108 pointing away from the bottom surface 112 is flush with a surface of the gear wheel 102 adjoining the depression 112 .

The diameter of the bottom surface 112A is larger than the diameter of the magnet 108 perpendicular to the axis of rotation 104. Accordingly, the magnet 108 is spaced from an edge surface or sidewall 112B of the recess 112 by a gap 114 along its entire circumference. The gap 114 can have a width of between 0.2 mm and 1 mm, for example, with the magnet 108 preferably being arranged in the recess 112 in such a way that the gap 114 has an approximately constant width over its entire length.

The hold-down 110 comprises a ring having an outer diameter greater than the diameter of the bottom surface 112A while the inner diameter is smaller than the diameter of the bottom surface 112A. Correspondingly, the hold-down device 110 can be placed on the gear wheel 102 in such a way that the hold-down device 110 extends along the edge surface 112B and completely covers the gap 114 . An energy director 116 is disposed on a surface 110A of the hold-down device 110 facing the gear 102 . The energy director 116 may be formed integrally with the hold-down and is preferably made of an ultrasonically weldable material, e.g., a thermoplastic such as polyamide, so that the energy director can be bonded to the gear 102 by ultrasonic welding.

The energy director 116 protrudes from the surface 110A and has a taper ing, triangular cross-section with two inclined side faces relative to a normal vector of the surface 110A, which converge to a point at an end of the energy director 116 remote from the surface 110. The energy director 116 follows a circle or ring on the surface 110A and is sized so that the path of the energy director 116 corresponds to the path of the gap 114 . The energy director 116 can be designed, for example, as a continuous web or as a large number of lugs spaced apart from one another. The height of the energy director, ie the distance between the tip of the energy director 116 and the surface 110A, may be between 0.1 mm and 2 mm, for example, between 0.3 mm and 1.2 mm in one example. Preferably, a welding distance when welding the hold-down device 110 is smaller than the height of the energy director and is, for example, between 20% and 50% of the height of the energy director.

The energy director 116 is configured to be at least partially inserted into the gap 114 between the magnet 108 and the edge surface 112B of the recess 112 along its entire length when the hold-down 110 is placed on the gear 102 . The width of energy director 116 at its tip is less than the width of gap 114, while the width of energy director 116 at surface 110A is greater than the width of gap 114. FIG. Accordingly, the tip of the energy director 116 can be inserted into the gap 114 . At this time, the two inclined side surfaces of the energy director 116 come into contact with an upper edge of the peripheral surface 112B and an upper edge of the magnet 108, respectively. As in the cross section in the 1b 1, a first portion of energy director 116 is located in the gap 114 between the magnet 108 and a left sidewall portion of the recess 112, while a second portion of the energy director 116 is in the gap 114 between the sensor element 108 and a right sidewall portion, opposite the left sidewall portion, of the Recess 112 is positioned so that the magnet 108 is centered in the recess 112 by the energy director.

Except for the energy director 116, the surface 110A of the hold-down 110 is spaced from both the surface of the gear 102 adjacent the rim surface 112B and the top 108A of the magnet 108. The gaps between the surface 110A and the gear wheel 102 or the magnet 108 can each have a width between 0.1 mm and 2 mm, for example. The width of the gap is preferably larger than a welding distance when welding the hold-down device 110 to the gear wheel 102, so that the surface 110A is also spaced apart from the gear wheel 102 and the magnet 108 after welding.

After laying down the hold-down 110, a welding operation may be performed to weld the hold-down 110 to the gear 102 and thus attach the magnet 108 to the gear, for example as described below for method 800 of FIG 8th described. The materials of the corresponding surfaces of gear wheel 102 and magnet 108 as well as of energy director 116 are preferably selected in such a way that energy director 116 is bonded to gear wheel 102 by welding, while energy director 116 and magnet 108 are not welded to one another, but only be positively connected.

In 2a , 2 B an arrangement 200 with a support element 102, a sensor element 108 to be fastened and a hold-down device 110 is shown according to an example. 2a shows the arrangement 200 in cross-section and 2 B in an exploded view.

In this example, the support element 102 is an output gear for an actuator, for example the actuator 300 3 . The output gear 102 is similar to the gear from 1a , 1b formed and also has a recess 112 with a bottom surface 112A and an outer edge surface 112B on one end face. The bottom surface 112A extends annularly around an output shaft 106 which runs along the axis of rotation 104 of the output gear 102 and has a driving profile 106A which is adapted to be mechanically coupled to an actuator. The outside of output shaft 106 forms an inner edge surface or side wall of recess 112.

A likewise ring-shaped magnet 108 is arranged in the recess, which in this case serves as an example of a sensor element to be fastened to the driven wheel 102 . An outer diameter of the bottom surface 112A is larger than an outer diameter of the magnet 108 such that the magnet 108 is spaced from the edge surface 112B of the recess 112 by a gap 114 . Magnet 108 has an opening 108B configured to fit over output shaft 106 . A plurality of centering elements 202 are located on the inner edge surface of the recess 112, which come into contact with an inner side of the magnet 108 and thus enable the magnet 108 to be arranged in the recess 112 without radial play. In the example of 2a , 2 B are the Centering elements 202 from the inner edge surface of the recess 112 protruding ribs 202A, 202B, which are arranged in the circumferential direction about the axis of rotation 104. The outer surfaces of centering ribs 202A are arranged along a circle around the axis of rotation 106 .

The arrangement 200 also includes an anti-rotation device, which is set up to hold the magnet 108 in the recess 112 in a rotationally fixed manner. For this purpose, one or more anti-rotation ribs 202B are wider than the centering ribs 202A and have flattened outer surfaces, which are each set up to engage with a corresponding phase or bulge 108C on the inside of the magnet 108 when the magnet 108 is arranged in the recess 112 is. The magnet 108 can have, for example, a bulge 108C or preferably two opposing bulges 108C as in the example in FIG 2 B . The bulges 108C on the inside of the magnet 108 can, for example, have a cross section in the shape of a segment of a circle perpendicular to the axis of rotation 104 and the flattened outer surfaces of the ribs 202B can accordingly run along a chord of a circle.

The magnet 108 also has an annular collar 108D on its inner periphery which extends from the top 108A of the magnet 108 parallel to the axis of rotation 104 . Correspondingly, the magnet 108 has an L-shaped cross section in a plane parallel to the axis of rotation 104 . The collar 108D can, for example, protrude from the upper side 108 by a length which corresponds to 0.5 to 2 times the thickness of the magnet 108 perpendicular to the surface 108A.

The hold-down 110 is similar to the assembly 100 of FIG 1a , 1b ring-shaped, so that the hold-down device 110 can be placed on the output gear 102 and the magnet 108 via the output shaft 106 . The hold-down 110 has an energy director 116 also annular on a first surface or underside 110A facing the gear 102 . This is similar to the energy director 1a , 1b formed and adapted to be inserted into the gap 114 between the magnet 108 and the edge surface 112B and to be connected to the output gear 102 by ultrasonic welding.

In the example of 2a the upper edge of the edge surface 112B protrudes above the upper side 108A of the magnet 108, ie the surface of the output gear 102 adjacent to the edge surface 112B is higher than the upper side 108A. Accordingly, the portion of the hold-down device 110 radially inward of the energy director 116 and facing the top surface 108A of the magnet 108 may have a greater thickness perpendicular to the first surface 110A than the portion of the hold-down device that is outward of the energy director 116 and facing the output gear 102 . As a result, the stability of the hold-down device 110 can be increased without increasing the external dimensions of the arrangement 200 .

Similar to the magnet 108, the hold-down device 110 also has a collar 110C, which is arranged along an inner circumference of the hold-down device 110 and protrudes parallel to the axis of rotation 104 from a second surface 110B of the hold-down device 110 opposite the first surface 110A. The collar 110C can, for example, protrude from the second surface 110B by a length that corresponds to 0.5 to 2 times the thickness of the hold-down device 110 perpendicular to the first surface 110A. Such a shape can both increase the stability of the hold-down device 110 and simplify production of the hold-down device 110, for example by means of injection molding.

3 shows an example of an actuator 300 with an electric motor 302, which comprises an arrangement according to the invention with a sensor element fastened to a support element by means of a hold-down device, in this example the arrangement 200 2a , 2 B . The electric motor 302 can be, for example, a small electric motor, in particular a brushless DC motor or a stepper motor. The electric motor 300 has a motor unit 302, which can include, for example, a rotatably mounted rotor 710 with one or more permanent magnets 712 and a stator 714. The stator 714 may include a plurality of phase windings 716 configured to generate a time-varying magnetic field to set the rotor 710 in motion.

The rotor 710 of the electric motor 302 is mechanically coupled to the driven wheel 102 of the arrangement 200 via a gear 304 such that a movement of the rotor is translated into a rotary movement of the driven wheel 102 . The gear 304 can, for example, comprise a spur gear and/or a worm gear and can in particular be designed as a reduction gear. In the example, the gear 304 includes a drive gear wheel 718 of the rotor 710, a total of three intermediate gears 720, 722, and 724, and the output gear 102. The actuator 300 also includes a housing 306, in which the electric motor 302, the gear 304 and the assembly 200 are arranged. The output shaft 106 of the output gear 102 is arranged in an opening in the housing 306, so that an actuator (not shown) located outside of the actuator 300 with the driving profile 106A of the output shaft 106 mechanically can be coupled. The rotor and the intermediate wheels 720, 722 and 724 are rotatably mounted on axles 728, the axles 728 being mounted in protrusions designed as axle bearings on the inside of the housing 306. The intermediate wheels 720, 722, 724 are designed as double gears.

A plug connection 732 is provided on the housing 306 for the power supply and control of the actuator 300, via which a control circuit of the actuator can be electrically contacted.

The actuator 300 can also include a magnetic field sensor and a control unit (not shown), the magnetic field sensor being arranged in the vicinity of the magnet 108 attached to the driven wheel 102 and being set up to determine a strength and/or direction of the magnetic field generated by the magnet 108 to determine. The magnetic field sensor can be a two- or three-dimensional Hall sensor, for example, which is set up to measure the strength of the magnetic field along two or three axes. The control unit can be set up to use a sensor signal output by the magnetic field sensor to determine a position of the driven wheel 102 or of an actuator coupled thereto, for example by means of a corresponding calibration curve. In particular, the magnetic field sensor can be arranged, as shown, on a printed circuit board 730 fastened in the housing 306 . The magnetic field sensor can then be connected to a microcontroller likewise arranged on the printed circuit board 730 via conductor tracks. The microcontroller can also be set up to control electric motor 302 and, for example, include a bridge circuit for commutating electric motor 302 . The printed circuit board 730 is arranged, for example, lying above the stator 714 in a plane perpendicular to the axis of rotation of the rotor 710 and can extend as far as the output gear 102 . The magnetic field sensor is then advantageously arranged on the circuit board 730 in the vicinity of the driven wheel 102 .

4a , 4b and 4c 12 show an arrangement 400 with a driven wheel 102 and a cylindrical magnet fastened to the driven wheel 102 by means of a disk-shaped hold-down device 110 according to an example. 4a shows the arrangement 400 in cross section, 4b in a perspective view and 4c FIG. 4 shows an enlarged detail view of the arrangement 400 in cross section.

Arrangement 400 is similar to arrangement 200 of FIG 2a , 2 B educated. In contrast to the arrangement 200, in the arrangement 400 the magnet 108 is arranged in a depression 112 on the end face of the output gear 102 which faces away from the output shaft 106. The recess 112 has a cylindrical shape with the axis of rotation 104 of the driven gear 102 passing through the bottom surface of the recess 112 . In the example of 4a For example, magnet 108 is formed as a hollow cylinder with an opening 108B extending through magnet 108 along the cylinder axis. In other configurations, the magnet 108 can be designed as a solid cylinder and have no opening.

The hold-down 110 of the assembly 400 includes a continuous disc that completely covers the magnet 108 and the opening 108B. The hold-down device 110 can, for example, 5 shown hold-down correspond. In some configurations, the hold-down device 110 can have a ventilation opening (not shown), for example to avoid sealing the opening 108B in an airtight manner.

Protruding from the surface 110A of the hold-down device 110 facing the output gear 102 is an energy director 116 which extends along a circle on the surface 110A concentrically around the center point of the hold-down device 110 and thus the axis of rotation 104 . Energy director 116 has an approximately triangular cross-section with two opposed side surfaces each inclined with respect to a normal vector of surface 110A. The two side surfaces are joined by a flattened end surface or tip at the end of energy director 116 opposite surface 110A, which end surface may be parallel to surface 110A. The width of the end face can be between 0% and 50%, in one example between 10% and 30% of a width of the energy director 116 on the surface 110A.

The end of energy director 116 remote from surface 110A is disposed in a gap 114 defined between an outer surface of magnet 108 and an edge surface 112B of cavity 112 . The radially inner side surface of the energy director 116 is in contact with an upper edge of the magnet 108, while the radially outer side surface of the energy director 116 is in contact or welded with an upper edge of the peripheral surface 112B. The two side surfaces have different angles of inclination with respect to the normal vector of the surface 110A, which in the example 4c is parallel to the axis of rotation 104 . For example, as in 4c shown, the angle of inclination of the outer face of energy director 116 relative to the normal vector may be less than that Angle of inclination of the inner side surface. The angle of inclination of the outer side surface can be, for example, between 10° and 30° and the angle of inclination of the inner side surface between 30° and 60°.

Furthermore, the hold-down device 110 has a smaller thickness in the edge region lying outside of the energy director 116 in the radial direction than in the inner region enclosed by the energy director 116 . The thickness of the hold-down device 110 in the edge area can be between 30% and 70% of the thickness in the inner area, for example. The thickness of the hold-down device 110 can be chosen such that the surface 110A of the hold-down device 110 is at a distance from both the driven wheel 110 and the magnet 108 . The top surface of hold-down device 110 opposite surface 110A is a flat surface and is perpendicular to axis of rotation 104.

6 shows a sensor element 108 to be fastened according to an example in a perspective view. The sensor element 108 to be attached can be a magnet, for example, in particular a rare earth magnet, for example a plastic-bonded neodymium-iron-boron magnet (NdFeB). Similar to the magnet of arrangement 400, the sensor element 108 to be attached is designed as a hollow cylinder with an opening 108B along the cylinder axis. The upper side 108A of the sensor element 108 to be fastened has a multiplicity of depressions 108E for an anti-twist protection, which extend in the radial direction from the upper edge of the opening 108B to the outside of the sensor element 108 to be fastened. The depressions 108E are each set up to engage with a corresponding counterpart of a hold-down device 110, for example a correspondingly shaped projection on the surface 110A, in order to arrange the sensor element 108 to be fastened in a rotationally fixed manner on a support element. Alternatively or additionally, the sensor element 108 to be fastened can also have corresponding depressions on its underside (not shown) and/or its outside, which are designed to connect with a corresponding counterpart on a receiving surface, for example the bottom surface 112A, or an edge surface, for example the Side wall 112B, interlock to locate the sensor element 108 to be secured against rotation on the receiving surface.

7 FIG. 7 shows an arrangement 700 with an output gear 102, an annular magnet 108 attached thereto and a hold-down device 110 with two energy directors 116, 704 according to an example in cross-section. The output gear 102 is similar to the output gear of assembly 400 4a-c formed and additionally has a centering mandrel 702 on the bottom surface 112A of the depression 112 . Centering pin 702 is located at the center of bottom surface 112A and extends from bottom surface 112A along the axis of rotation of output gear 102. Magnet 108 has an opening into which centering pin 702 can be inserted when the magnet is placed in recess 112 . The length of the centering mandrel 702 is selected such that an upper side of the centering mandrel 702 is flush with the upper side of the magnet 108 when the magnet 108 is arranged on the bottom surface 112A. The width or diameter of the centering pin 702 may be smaller than the width or diameter of the opening in the magnet 108, for example so that the magnet 108 is spaced from the centering pin 702 by a gap 706 when the magnet 108 is placed on the receiving surface 112A is.

The hold-down 110 is similar to the hold-down 5 disk-shaped and has, in addition to a first, outer energy director 116, which runs along an outer circumference of the hold-down device 110, a second, inner energy director 704, which also protrudes from the surface of the hold-down device 110 facing the driven wheel 102. For example, the internal energy director 706 may comprise a circular circumferential ridge having a triangular cross-sectional area. The inner energy director 704 is positioned on the holddown 110 such that the inner energy director 704 comes into contact with the top of the centering mandrel 702 when the holddown 110 is placed on the output gear 102 . The inner energy director 704 can, for example, comprise a material which can be welded to the centering mandrel 702 by ultrasonic welding, for example in order to produce a further material connection between the output wheel 102 and the hold-down device 110 .

In other embodiments, internal energy director 704 may also be positioned on holddown 110 such that internal energy director 704 contacts the top of magnet 708 . The inner energy director 704 can, for example, comprise a material which cannot be welded to the magnet 108 by ultrasonic welding, but which at least partially melts during an ultrasonic welding process in order to produce a form-fitting connection between the hold-down device 110 and the upper side of the magnet 108. In one embodiment, the inner energy director 704 can also be arranged on the hold-down device 110 in such a way that the inner energy director 704 at least partially fits into the gap 706 between the centering mandrel 702 and the inner side of the magnet 108, for example similar to the outer energy director 116.

The output gear 102 also has one or more centering elements 202 which are arranged in a lower region of the recess 112 and are each configured to come into contact with the magnet 108 in order to center the magnet 108 in the recess 112 . The centering elements 202 can be formed, for example, in the form of ribs or projections on the outer edge surface 112B of the depression 112 . In another example, the centering element 202 can be a lower portion of the edge surface 112B, which can have a smaller diameter than an upper portion of the edge surface 112B, for example, such that the lower portion of the edge surface 112B comes into contact with the magnet 108, while the upper portion edge surface 112B is spaced from magnet 108 by gap 114 .

8th 8 shows a flow diagram of a method 800 for attaching a sensor element to a rotatable component for an actuator according to an example. The method 800 may be used to turn off the magnet 108 of the assembly 200, for example 2a , 2 B to be fastened to the driven wheel 102 by means of the hold-down device 110 . The arrangement 200 is therefore used below to illustrate the steps of the method 800 by way of example. However, this is in no way to be understood as limiting and the method 800 can also be used to attach other sensor elements to rotatable components of an actuator, for example to manufacture or assemble one of the assemblies 100, 400 or 700 described above.

The method 800 includes, in step 802, placing the magnet 108 in the cavity 112 on the output gear 102 by passing the output shaft 106 through the opening 108B in the magnet 108 and placing the magnet 108 on the cavity bottom surface 112A. The magnet 108 is rotated about the axis of rotation 104 in such a way that the bulges 108C on the inside of the magnet 108 are flush with the outer surfaces of the anti-rotation ribs 202B on the outside of the output shaft 106 and come into contact with them when the magnet 108 is in the recess 112 is introduced. As a result, a non-rotatable arrangement of the magnet 108 in the recess 102 can be achieved and a defined alignment of a magnetization axis of the magnet 108 relative to the driven wheel 102. Furthermore, the magnet 108 is centered by the ribs 202A, 202B in the recess 112, so that the outside of magnet 108 is spaced from edge surface 112B of recess 112 along its entire length by a gap 114 of uniform width. The ribs 202A, 202B can, for example, be designed in such a way that the magnet 108 is pressed into the depression 112 with slight pressure and is held in the depression 112 by the ribs 202A, 202B without radial play.

Then, in step 804 , hold-down device 110 is placed on driven wheel 102 and magnet 108 arranged in depression 112 . In doing so, the energy director 116 on the underside 110A of the hold-down device 110 is partially inserted into the gap 114 between the magnet 108 and the side wall 112B of the recess so that the inclined side surfaces of the energy director 116 are in contact with the top edge of the side wall 112B or the upper outer edge of magnet 108 and the tip of energy director 116 is located in gap 114 between magnet 108 and sidewall 112B. The areas of the underside 110A of the hold-down device 110 adjoining the energy director 116 can be spaced apart from the surface of the output gear 102 adjoining the side wall 112B and the upper side 108A of the magnet 108 .

In the example of the arrangement 200, the energy director 116 is a circumferential web and consequently extends in the circumferential direction along the entire gap 114. H. in each case between opposite sections of the side wall 112B and the magnet 108. As a result, the magnet 108 can also be centered in the depression 112 by means of the hold-down device 110, independently of the presence of the ribs 202A, 22B.

After the hold-down device 110 has been placed, a welding process is carried out in step 806 in order to fasten the magnet 108 to the output wheel 102 by means of the hold-down device 110 . The hold-down device 110 is preferably bonded to the upper edge of the side wall 112B by ultrasonic welding. For this purpose, a high-frequency mechanical vibration is transmitted to the hold-down device 110, the driven wheel 102 and/or the magnet 108. In one example, the vibration is transmitted over a large area to the entire hold-down device 110 via a flat sonotrode in the axial and/or radial direction. In another example, the vibration is transmitted via a punctiform sonotrode to a limited portion of the hold-down device 110 and the sonotrode in the course of the ultrasonic welding process in the circumferential direction along the course of the Energy director 116 moves. The frequency of the oscillation can be in the range between 10 kHz and 40 kHz, for example, and can be 20 kHz, for example. The duration of the ultrasonic welding process can be between 100 ms and 2 s, for example. Step 806 may also include a cooling process to resolidify material liquefied during the ultrasonic welding process. The duration of the cooling process can be between 300 ms and 3 s, for example.

During the ultrasonic welding process, the energy director 116 and the corresponding bearing or contact surface along the top edge of the side wall 112B are liquefied in whole or in part and a bonded bond is formed which is subsequently hardened. This can be achieved, for example, by selecting a suitable material, with the driven wheel 102 and the hold-down device 110 with the energy director 116 preferably comprising the same material. In one example, hold down 110 is integrally formed with energy director 116 from polyamide while output gear 102 is made from glass fiber reinforced polyamide. During the ultrasonic welding, pressure can be applied to the hold-down device 110 and/or the driven gear 102, for example along the axis of rotation 104, in order to press the hold-down device 110 and the driven gear 102 together. The weld travel, i.e. the amount by which the distance between the surface 102 of the blank holder 110 and the driven wheel 102 or the magnet 108 is reduced during the welding process, can be between 0.05 mm and 1.5 mm, for example between 0.2mm and 1mm.

In some embodiments, the contact surface of the magnet 108 with the energy director 116 is made of a material that cannot be ultrasonically welded to the energy director 116 and, for example, is not liquified during the ultrasonic welding process. Correspondingly, after the liquefied energy director 116 has hardened, a form-fitting connection can be produced between the hold-down device 110 and the magnet 108, by means of which the magnet 108 is held in the recess 112 without play in the axial direction. The magnet 108 is preferably only fastened to the output gear 102 by the hold-down device 110 and, for example, is not additionally glued to the output gear 102 or otherwise attached to the output gear 102 . In other embodiments, the contact surface of the magnet 108 is made of a material that can be ultrasonically welded to the energy director 116, for example to create a bonded connection between the hold-down device 110 and the magnet 108 as well. For this purpose, the magnet 108 can be provided with a suitable thermoplastic coating, for example.

In addition to the in 8th From the steps described above, the method 800 can in some configurations also comprise further steps, for example the installation of the assembly 200 in an actuator such as the actuator 300 3 . For example, as in 3 shown, a guide shaft of the driven gear opposite the driven shaft 106 can be arranged in a guide or bearing in a side wall or a cover of the housing 306 . The output shaft 106 may be disposed in an opening in an opposite side wall or bottom of the housing 306, which opening may also include a guide or bearing for the output gear 102. Method 800 may further include locating a magnetic field sensor, such as a Hall effect sensor, proximate output gear 102 .

The described embodiments according to the invention and the figures are only intended as purely exemplary illustrations. The invention can vary in its form without changing the underlying functional principle. The scope of protection of the method according to the invention and the device according to the invention results solely from the following claims.

Reference List

100

arrangement

102

gear/driven gear

104

axis of rotation

106

output shaft

108

magnet

108A

Top of magnet 108

108B

Opening in the magnet 108

110

hold-down

110A

first surface of hold-down 110

112

deepening

112A

recording area/floor area

112B

edge surface/side wall

114

gap

116

first energy director

200

arrangement

202

centering elements

202A

centering ribs

202B

anti-twist ribs

108C

Bulge of magnet 108

108D

Magnet 108 collar

110B

second surface of the hold-down 110

110C

Collar of the hold-down 110

300

actuator

302

motor unit/electric motor

304

transmission

306

Housing

400

arrangement

108E

Depression in the magnet 108

700

arrangement

702

centering mandrel

704

second energy director

706

gap

710

rotor

712

permanent magnets

714

stator

716

phase windings

718

drive wheel

720, 722, 724

intermediate wheels

728

Axles

730

circuit board

732

connector

800

Method of attaching a sensor element to a rotary electric motor component

802

Arranging the sensor element to be fastened

804

Laying down the hold-down device

806

ultrasonic welding process

Claims (27)

A method (800) for attaching a sensor element (108) to a rotatable component (102) for an actuator (300) by means of a hold-down device (110), wherein: the rotatable member (102) has a recess (112) extending about an axis of rotation (104) of the member (102); and the hold-down (110) includes an energy director (116) protruding from a surface (110A) of the hold-down (110); the method (800) comprising: placing the sensor element (108) in the recess (112) on the rotatable member (102); Placing the hold-down device (110) on the rotatable component (108) so that the energy director (116) is at least partially arranged in a gap (114) between the sensor element (108) and a side wall (112B) of the recess (112) and in contact with the rotatable member (102) and the sensor element (108); and Performing a welding process to attach the sensor element (108) to the rotatable component (102) using the hold-down device (110). Method (800) according to claim 1 , wherein the hold-down device (110) is placed on the rotatable component (102) in such a way that areas of the surface (110A) of the hold-down device (110) adjoining the energy director (116) are separated from the rotatable component (102) and/or or the sensor element (108) are spaced. Method (800) according to claim 1 or 2 , wherein the energy director (116) has two opposite side surfaces, each of which is inclined with respect to a normal vector of the surface (110A) of the hold-down device (110), and the hold-down device (110) is placed on the rotatable component (102) such that one of the inclined side surfaces of the energy director (116) comes into contact with an upper edge of the side wall (112B) of the recess (112) and an edge of the sensor element (108), respectively. Method (800) according to one of the preceding claims, wherein the welding process creates a material connection between the hold-down device (110) and the rotatable component (102) and/or a positive connection between the hold-down device (110) and the sensor element (108). . A method (800) according to any one of the preceding claims, wherein the welding process comprises an ultrasonic welding process. Method (800) according to one of the preceding claims, wherein the method (800) further comprises pressing the sensor element (108) into the depression (112), so that the sensor element (108) is arranged with a centering element (112) in the depression (112). 202) comes into contact. The method (800) of any preceding claim, wherein a first portion of the energy director (116) is inserted into a gap between the sensor element (108) and a first sidewall portion of the recess (112) and a second portion of the energy director (116) is inserted into a Gap between the sensor element (108) and a second side wall section of the recess (112) opposite the first side wall section, in order to center the sensor element (108) in the recess (112). The method (800) of any preceding claim, wherein the sensor element (108) is a magnet, and the method (800) further comprises aligning an axis of magnetization of the magnet relative to the rotatable member (102). Method (800) according to one of the preceding claims, wherein the rotatable component (102) is a gear wheel, in particular a driven wheel. Arrangement (100, 200, 400, 700) with a support element (102), a sensor element (108) to be fastened and a hold-down device (110), which is designed to be connected to the support element (102) by welding in order to to attach the sensor element (108) to be attached to the support element (102), wherein: the support member (102) has a receiving surface (112A) adapted to receive the sensor element (108) to be attached and an edge surface (112B) extending along an edge of the receiving surface (112A); the sensor element (108) to be fixed is spaced from the edge surface (112B) by a gap (114) when the sensor element (108) to be fixed is arranged on the receiving surface (112A); and the hold-down (110) has a first energy director (116) protruding from a first surface (110A) of the hold-down (110) and adapted to at least partially fit into the gap (114) between the sensor element (108) to be attached and the Edge surface (112B) to be inserted when the hold-down (110) is placed on the support member (102). Arrangement (100, 200, 400, 700) according to claim 10 , wherein a dimension of the receiving surface (112A) is greater than a dimension of the sensor element (108) to be fastened. Arrangement (100, 200, 400, 700) according to claim 10 or 11 , wherein the first energy director (116) tapers from the first surface (110A) of the hold-down (110) to an end of the first energy director (116) remote from the first surface (110A) of the hold-down (110) and a width of the first Energy director (116) on the first surface (110A) of the hold-down (110) is greater than a width of the gap (114) between the sensor element to be attached (108) and the edge surface (112B). Arrangement (100, 200, 400, 700) according to one of Claims 10 until 12 , wherein the first energy director (116) has two opposite side surfaces, each inclined with respect to a normal vector of the first surface (110A) of the hold-down (110), and one of the inclined side surfaces in contact with the support element (102) and the one to be fastened, respectively Sensor element (108) is when the first energy director (116) is located in the gap (114) between the sensor element (108) to be attached and the edge surface (112B). Arrangement (100, 200, 400, 700) according to one of Claims 10 until 13 wherein the first energy director (116) comprises a circumferential ridge protruding from the first surface (110A) of the hold-down (110), or a plurality of spaced-apart tabs each protruding from the first surface (110A) of the hold-down (110) protrude. Arrangement (100, 200, 400, 700) according to one of Claims 10 until 14 , wherein regions of the first surface (110A) of the hold-down device (110) adjoining the first energy director (116) are spaced apart from the support element (102) and/or the sensor element (108) to be fastened, at least before the welding process when the first energy director ( 116) is arranged in the gap (114) between the sensor element (108) to be fastened and the edge surface (112B). Arrangement (100, 200, 400, 700) according to one of Claims 10 until 15 , wherein the first energy director (116) and the support element (102) comprise materials that can be welded together by ultrasonic welding, while the sensor element (108) to be attached comprises a material that cannot be welded to the first energy director (116) by ultrasonic welding. Arrangement (200) according to one of Claims 10 until 16 wherein the hold-down (110) is ring-shaped and has on its inner or outer periphery a collar (110C) defined by one of the first Surface (110A) opposite second surface (110B) of the hold-down (110) protrudes. Arrangement (200, 400, 700) according to one of Claims 10 until 17 , wherein the support element (102) has a centering element (202) which is adapted to come into contact with the sensor element (108) to be fastened when the sensor element (108) to be fastened is arranged on the receiving surface (112A). Arrangement (200, 400, 700) according to one of Claims 10 until 18 wherein the hold-down (110) has different thicknesses in regions of the first surface (110A) located on opposite sides of the first energy director (116). Arrangement (700) according to one of Claims 10 until 19 , wherein the hold-down device (110) further comprises a second energy director (704) which is set up to come into contact with the sensor element (108) to be fastened and/or the supporting element (102) when the hold-down device (110) is on the Supporting element (102) is placed. arrangement (200) after claim 20 wherein the first energy director (116) extends around the second energy director (704). Arrangement (200) according to one of Claims 10 until 21 , wherein the arrangement comprises an anti-twist device in order to arrange the sensor element (108) to be fastened in a rotationally fixed manner on the receiving surface (112A). arrangement according to Claim 22 , wherein the anti-rotation device comprises a securing element on the hold-down device (110) which is designed to engage with a corresponding counterpart (108E) on the sensor element (108) to be fastened in order to rotate the sensor element (108) to be fastened on the receiving surface (112A) to arrange. Arrangement (700) according to one of Claims 10 until 23 , wherein the support element (102) has a structure (106, 702) which protrudes from the receiving surface (112A) and is adapted to be inserted into an opening (108B) in the sensor element (108) to be fastened. Arrangement (100, 200, 400, 700) according to one of Claims 10 until 24 , wherein the sensor element (108) to be fastened is arranged on the receiving surface (112A) and is fastened to the support element (102) by means of the holding-down device (110). Arrangement (100, 200, 400, 700) according to one of Claims 10 until 25 , wherein the support element (102) is a rotatable component, in particular a gear wheel, for an actuator (300) and/or the sensor element (108) to be fastened is a magnet. Actuator (300) with an electric motor (302) and an arrangement (100, 200, 400, 700). Claim 26 , wherein a printed circuit board (732) is arranged in the actuator (300) and the sensor element (108) to be fastened is a magnet, and wherein a magnetic sensor for detecting a rotary angle position of the rotatable component is arranged.

Images