Trailer coupling having a coupling-arm carrier and method for producing said trailer coupling

Abstract

The invention relates to a trailer coupling for a motor vehicle (100) for coupling a trailer (AH) or a rear load carrier (LT), comprising a vehicle mount (95), which can be or is fastened to the motor vehicle (100) and which has a mounting base (11), on which mounting base, at least in a usage position (G) provided for coupling the trailer (AH) or the rear load carrier (LT), a mounting portion (53; 353) of a coupling-arm carrier (50; 250; 350; 450) is mounted, wherein, at least in the usage position (G), a receiving portion (59) having a coupling-arm receptacle (60) for receiving a coupling arm (80) is disposed on the mounting portion (53; 353) of the coupling-arm carrier (50; 250; 350; 450), said coupling arm forming, in particular, a part of the trailer coupling (10), and wherein the coupling-arm receptacle (60) is in the form of an insertion receptacle (60A) having an insertion opening (66), through which, at least in the usage position (G), the coupling arm (80) can be inserted along an insertion axis (K) into the coupling-arm receptacle (60), such that the coupling arm is ready for coupling the trailer (AH) or rear load carrier (LT). According to the invention, the coupling-arm receptacle (60) has at least one supporting surface (62, 63) for supporting the coupling arm (80), said supporting surface being produced by machining.

Description

[0001] Trailer coupling with a coupling arm support and

[0002] Process for their production

[0003] The invention relates to a trailer coupling for a motor vehicle for coupling a trailer or a rear load carrier, with a vehicle mount that can be fastened or is fastened to the motor vehicle and has a holding base on which a coupling arm support is held by a holding section, at least in a position of use intended for coupling the trailer or the rear load carrier, wherein a receiving section with a coupling arm receptacle for receiving a coupling arm, which in particular forms a component of the trailer coupling, is arranged on the holding section of the coupling arm support, at least in the position of use, wherein the coupling arm receptacle is designed as a plug-in receptacle with an insertion opening, through which the coupling arm can be inserted into the coupling arm receptacle along a plug-in axis, at least in the position of use, and is ready for coupling the trailer or rear load carrier.The invention further relates to a method for producing such a trailer coupling.

[0004] Such a trailer coupling is described, for example, in WO 2023 / 280957 A1.

[0005] The coupling arm mount is designed, for example, as a mounting tube that is connected to the holding section, for example, by means of a fork-like mount on the holding section or an arm section protruding from the holding section. The load-bearing capacity of such a construction is not always satisfactory. Therefore, the object of the present invention is to provide an improved trailer coupling.

[0006] To achieve this objective, a trailer coupling of the type mentioned at the outset is provided with the coupling arm holder having at least one support surface produced by machining for supporting the coupling arm.

[0007] To achieve the object, a method for producing a trailer coupling for a motor vehicle is further provided, wherein the trailer coupling is provided for coupling a trailer or a rear load carrier, wherein the trailer coupling has a vehicle mount that can be fastened or is fastened to the motor vehicle, wherein the vehicle mount has a holding base on which a coupling arm carrier is held by a holding portion at least in a use position intended for coupling the trailer or the rear load carrier, wherein a receiving portion with a coupling arm receptacle for receiving a coupling arm, in particular forming a component of the trailer coupling, is arranged on the holding portion of the coupling arm carrier, at least in the use position, wherein the coupling arm receptacle is designed as a plug-in receptacle with an insertion opening,by means of which the coupling arm can be inserted into the coupling arm receptacle along a plug-in axis, at least in the position of use, and is ready for coupling the trailer or rear load carrier, wherein the method comprises machining a raw support surface of the coupling arm receptacle using a cutting tool to produce a support surface of the coupling arm receptacle, which support surface is provided and designed to support the coupling arm.

[0008] The basic idea is that one or more support surfaces, which support the coupling arm when it is inserted into the coupling arm receptacle, are produced by machining, with the machining being carried out, for example, on a blank previously manufactured as a cast or forged part. This makes it easy to produce support surfaces in the form of flat surfaces or flat surfaces, which enable optimal support of the coupling arm. It is possible for the coupling arm to rest directly on the support surface, in particular the flat surface, or for the support surface to serve to support a receiving sleeve, which will be described in more detail below, but which is held in an optimally form-fitting manner due to its contact with the flat surface or support surface.

[0009] However, it is also advantageous for holding the receiving sleeve if one or more support surfaces of the coupling arm holder are machined. Thus, it is possible for the machined support surface of the coupling arm holder to directly support the coupling arm when it is inserted into the coupling arm holder, or to support it indirectly by positively supporting a receiving sleeve on the support surface.

[0010] It is also possible for the receiving sleeve to only partially cover the coupling arm receptacle, i.e., for example, one or more support surfaces are provided directly on the coupling arm receptacle for directly supporting the coupling arm, while additional support surfaces for supporting the coupling arm are provided by the receiving sleeve. For example, a bottom-side support surface can advantageously be produced by machining the coupling arm receptacle, while an opposite top-side support surface forms part of the receiving sleeve.

[0011] A preferred concept provides that the holding section of the coupling arm support, which is held on the holding base (e.g., pivotably mounted), and the receiving section of the coupling arm support, which has the coupling arm receptacle, are integrally formed. This enables a particularly rigid design of the coupling arm support.

[0012] It is preferred if the clutch arm support is a forged or cast part.

[0013] For example, a blank for the clutch arm support is initially produced by casting and / or forging. Especially with forging, it is possible that appropriate thermal processing of the clutch arm support or a blank for the clutch arm support can result in a particularly strong structure, meaning that the clutch arm support is highly resilient. It is also possible for a cast part to be subsequently at least partially forged to provide the blank for the clutch arm support.

[0014] Advantageously, an arm section or arm body is arranged between the holding section and the receiving section. The holding section, the arm section, and the receiving section can be integral.

[0015] At this point, however, it should also be mentioned that it is possible, for example, for the receiving section with the coupling arm receptacle and the arm section to be manufactured as a one-piece component or from a single blank, while the holding section is provided by a holding body, for example a plug-in body or plug-in projection or bearing body, to which the arm section is fastened, for example screwed, welded or the like. In this embodiment, too, it proves advantageous if the coupling arm receptacle has one or more support surfaces that are or are manufactured by machining. The receiving section with the coupling arm receptacle, which is one-piece with the arm section, can withstand particularly high loads.

[0016] It is advantageous if the coupling arm receptacle has a polygonal cross-section with mutually angled support surfaces for the coupling arm, wherein at least one support surface, preferably all support surfaces, are machined. In particular, the coupling arm receptacle has a rectangular or square cross-section. The support surfaces are, for example, opposing and mutually angled support surfaces. One or more, in particular opposing, support surfaces can be machined. However, it is also possible for, for example, two mutually angled support surfaces to be non-machined, opposite which two further mutually angled support surfaces are machined.Thus, for example, the support surfaces produced by machining can be machined in such a way that a predetermined distance is created from a non-machined support surface opposite the support surface.

[0017] It is advantageous if one or more, in particular all, support surfaces are designed as flat surfaces. The flat surfaces preferably extend over an entire longitudinal length along which the coupling arm can be inserted into the coupling arm receptacle.

[0018] Advantageously, the distance between opposing support surfaces along a plug-in section of the coupling arm receptacle extending along the plug-in axis is constant, with the coupling arm being insertable into the plug-in section of the coupling arm receptacle. The support surfaces are thus, for example, plane-parallel.

[0019] The following measure is particularly advantageous for facilitating machining:

[0020] Advantageously, at least one corner region or inner corner region between mutually angled support surfaces is designed as a receiving cavity for a cutting tool, which can engage in the receiving cavity without cutting with the latter during machining of at least one of the two mutually angled support surfaces. For example, such receiving cavities can also be used to remove a forging tool or a casting core from the coupling arm receptacle. The at least one receiving cavity is, for example, set back from the support surface produced by the tool and / or is at a distance from the support surface produced by the tool. The receiving cavity is, for example, designed as a recess in an inner corner region between mutually angled support surfaces arranged next to one another.Before machining or application of the cutting tool, the coupling arm holder advantageously has a rough contour or basic contour that is already essentially the same as and / or similar to the later coupling arm holder and / or is suitable for subsequent machining, for example, basically already has a polygonal cross-sectional contour. However, the so-called unmachined and raw support surfaces of this rough contour or basic contour still have so much material or protrude so far into the later coupling arm holder that material can be removed from the rough contour or basic contour by the subsequent machining in order to produce the at least one support surface, preferably all support surfaces, and / or an inner circumferential contour of the plug-in receptacle of the coupling arm holder by machining.

[0021] It is possible that surfaces intended for the production of the support surfaces or raw support surfaces of the coupling arm holder on a blank of the coupling arm carrier are initially inclined surfaces which are machined by the subsequent machining to form flat surfaces or flat support surfaces or flat support surfaces which extend parallel to one another at least along the plug-in section for the coupling arm.

[0022] For example, raw support surfaces of the raw contour or basic contour still have an oblique profile. The oblique profile is preferably in the sense of a narrowing away from the insertion opening. The oblique profile of such a raw support surface or several raw support surfaces arises, for example, because a casting core and / or a forging tool can or must be removed from a blank of the clutch arm support away from the insertion opening. Advantageously, a further opening is located opposite the insertion opening, so that from each opening, the insertion opening and this further opening, there can be raw support surfaces that are inclined away from each opening, the insertion opening and this further opening, which are later formed into the support surfaces of the clutch arm holder by machining using a tool or cutting tool.For example, inclined surfaces or raw support surfaces that conically converge from the insertion opening and / or the further opening can be provided, which are produced, for example, by a forging tool, a casting core or the like.

[0023] While it is fundamentally possible to use a milling tool or the like to produce one or all of the support surfaces, it is preferred, however, for the at least one support surface to be produced using a broaching tool, for example, a broach needle. Especially with this configuration, it is particularly advantageous if the aforementioned receiving cavities are present in the corner areas of the coupling arm receptacle for the outer corner areas of the broaching tool. The broaching tool, for example, is not subjected to stress at its outer edges, which reduces wear on the broaching tool during the production of the clutch arm receptacle.

[0024] It is possible to use several broaching tools, for example two, to produce a pair of opposing support surfaces each, for example, and / or to machine support surfaces sequentially, first with a first and then with a second broaching tool. The first broaching tool performs, for example, pre-machining, such as rough production of the support surface, and the second broaching tool performs finishing, such as fine grinding and / or production of a flat surface. It is also possible to produce a first part of a support surface using the first broaching tool and a second part of this support surface using the second broaching tool.However, it is preferred if several support surfaces, in particular opposing and / or mutually angled support surfaces, or even more preferably all support surfaces, of the coupling arm receptacle are machined by a single tool, in particular a single broaching tool.

[0025] The tool, in particular the broaching tool, is preferably designed to produce at least two support surfaces, preferably all support surfaces, of the coupling arm receptacle in a single operation and / or with a single feed movement along the coupling arm receptacle. When manufacturing the trailer coupling, it is advantageous if the coupling arm receptacle is the decisive geometric component for the use of forging tools and / or casting molds and / or determines the basic dimension of the coupling arm receptacle. It is advantageous, for example, if a casting mold and / or a forging tool is provided and designed to produce a basic contour or rough contour of the coupling arm receptacle and / or the basic contour or rough contour of the coupling arm receptacle is produced using a casting mold and / or a forging tool.For example, it can be provided that the clutch arm receptacle or a recess for producing the clutch arm receptacle is produced by at least one forging tool and / or a casting mold, which engages in the clutch arm receptacle, in particular from opposite sides of the clutch arm receptacle, during the forging of a blank of the clutch arm support. It is both possible that a casting mold is or has been used first and then a forging tool is used to produce the basic contour or rough contour of the clutch arm receptacle.

[0026] The raw contour or basic contour is then machined by a cutting tool to produce at least one support surface which is intended and designed to support the coupling arm.

[0027] It is possible for only a single forging tool or a single projection of a forging tool to engage in the clutch arm receptacle or serve to produce it. However, it is also possible for a forging tool or a projection of the forging tool to engage in the clutch arm receptacle from opposite sides or serve to produce it.

[0028] It is also possible for the clutch arm mount to be formed by a casting core that engages the clutch arm mount during the production of a blank for the clutch arm support. The clutch arm mount is thus essentially formed, for example, by the casting core or the forging tool to provide a basis for the subsequent machining of the clutch arm mount.

[0029] Using a first tool, for example a casting core, forging tool or the like, a first rough inner circumferential contour or rough contour of the clutch arm receptacle is produced. For example, the first tool is a non-cutting tool, e.g. the forging tool. However, the first tool can also be a cutting tool, for example a milling tool or the like. The rough inner circumferential contour can, for example, be directly machined by a second cutting tool, namely a cutting tool within the meaning of the invention, to form the final inner circumferential contour of the plug-in receptacle or clutch arm receptacle, wherein the second tool serves to produce at least one support surface for supporting the clutch arm. For example, flat surfaces can be directly produced in this way using the second cutting tool.

[0030] However, it is also possible for a raw inner peripheral contour, for example with inclined surfaces, to be produced using a casting core and / or a forging tool, whereby this raw inner peripheral contour is not yet suitable for final machining by the cutting tool within the meaning of the invention and / or for producing the at least one support surface. For example, raw support surfaces of the raw contour converge at an angle to one another, which prevents or at least complicates the insertion of the cutting tool.

[0031] In this initial situation, the measure explained below is particularly advantageous, but can of course also be applied in other initial situations:

[0032] Advantageously, the first tool used to produce the raw inner circumferential contour or rough contour is already a cutting tool, or the first tool may be a forging tool or casting core, but another cutting tool, i.e., a third tool or second first tool, is used before the second tool to prepare the raw inner circumferential contour or rough contour for the application of the second tool used to produce the at least one support surface. The cutting first tool has a first outer circumferential contour, for example, a rounded and / or non-polygonal outer circumferential contour, to produce the rough contour.

[0033] In a second, subsequent work step, a second tool is used which then, for example, machines this rough contour even further in the direction of the final inner circumferential contour of the coupling arm holder. However, it is also possible for the second tool to already carry out the final machining, for example forming the support surfaces as flat, level support surfaces. For example, the second tool is a broaching tool or a broach. The outer circumferential contour of the second tool is a second outer circumferential contour, which is, for example, a polygonal outer circumferential contour and differs from the first outer circumferential contour of the first tool, in particular geometrically and / or in terms of its geometric shape, e.g. differently polygonal or round and polygonal, and / or its circumferential length and / or its circumferential extension.Using the first tool, for example, a basic contour can be created that allows the second tool to be inserted into the rough contour of the coupling arm mount. The rough contour can be, for example, an approximately circular contour. The first machined tool can be, for example, a drilling tool or milling tool with a round outer peripheral contour.

[0034] At this point, it should be mentioned that the rough contour, which is used to produce one or more support surfaces through machining using the tool, can of course also be created by drilling a hole through a blank of the clutch arm support. This hole can, for example, be a circular hole or have a circular cross-section that is further machined into a polygonal inner circumferential contour by subsequent milling. However, it is also possible for the cutting tool used to produce the final inner circumferential contour of the clutch arm holder to be inserted into such a round raw inner cross-section, for example a broach is inserted, which forms the tool according to the invention for producing one or more support surfaces.

[0035] The components of the clutch arm support that are relevant for the accuracy of fit and geometry, namely the bore for the bearing mount and the clutch arm mount for the clutch arm, are manufactured by machining and are therefore particularly dimensionally accurate, especially in relation to one another.

[0036] In principle, it is possible for the coupling arm receptacle or the receptacle section to be arranged directly on the holding section. However, it is also possible for a gap to be present between the receptacle section and the holding section. In particular, it is advantageous if an arm section protrudes from the holding section of the coupling arm support, on which the receptacle section is arranged, wherein the holding section, the arm section, and the receptacle section are integral.

[0037] The arm section can comprise one or more arm bodies, each of which connects the receiving section and the holding section to one another. Such arm bodies can, for example, be arranged side by side. It is particularly advantageous if the arm body is a solid arm body.

[0038] The arm section advantageously has a substantially rectangular, square, or approximately square outer peripheral contour, or a rectangular, square, or approximately square envelope around its outer peripheral contour. "Approximately square" means that the longitudinal sides and transverse sides differ from each other in length or width by a maximum of 30%, in particular a maximum of 20%.

[0039] The arm section preferably has one or more reinforcing ribs. It is also advantageous if the arm section is straight and / or without any curvature. This makes the arm section particularly resilient.

[0040] Advantageously, a longitudinal axis of the arm section is at an angle to the pivot axis and / or at an angle to the plug-in axis of the coupling arm mount. The arm section can, for example, be connected to the mount section at a side wall of the coupling arm mount. The coupling arm support is pivotably mounted about the pivot axis between a non-use position, intended for non-use of the trailer coupling, and the use position. The pivot axis preferably forms a single pivot axis. Such a bearing concept will be explained in more detail below.

[0041] A particularly short arm section is preferred. It is advantageous, for example, if the longitudinal extension of the arm section between the holding section and the receiving section is shorter than the longitudinal extension of the receiving section parallel to the plug-in axis.

[0042] It is advantageous if the holding section is connected to the receiving section by a single arm body that forms the arm section. However, it is also possible for multiple arm bodies to form the arm section. The arm bodies are preferably connected to the holding section at one of their longitudinal ends and to the receiving section at their other longitudinal ends.

[0043] An advantageous concept provides for two arm bodies to extend side by side parallel to the through-hole axis or longitudinal axis of the coupling arm mount. It is also advantageous if all arm bodies are arranged parallel to each other with respect to the through-hole axis or longitudinal axis of the coupling arm mount, but not one behind the other in the direction of the through-hole axis.

[0044] In the case of trailer couplings with a coupling arm receptacle into which a coupling arm can be inserted, it is common for a bead to extend around the insertion opening in order to reinforce the coupling arm receptacle. This is advantageously provided, for example, in the receiving sleeve, which is described in detail below and is received in the coupling arm receptacle. On the receiving section itself, on which the coupling arm receptacle is arranged, such reinforcement by means of a bead is not absolutely necessary, since the coupling arm support can withstand significantly higher loads than a simple receiving sleeve. For example, it can be provided that a front wall surface of the receiving section, which extends around the insertion opening, is designed as a flat surface and / or as a surface produced by machining. For example, the front wall surface is produced as a flat surface by milling and / or grinding.

[0045] In principle, it is possible for the coupling arm receptacle to be open on one side only, i.e. to only have the insertion opening. On one of these opposite sides, for example, a base can be provided on the coupling arm receptacle. However, it is advantageous if the coupling arm receptacle has a further opening on a side opposite the insertion opening, wherein the further opening preferably has a plug-in cross-section suitable for inserting the coupling arm. Thus, for example, an object can be inserted through this further opening in order to remove the coupling arm from the coupling arm receptacle. It is also possible for the coupling arm to completely penetrate the coupling arm receptacle and to protrude in front of the coupling arm receptacle through the further opening opposite the insertion opening.

[0046] An advantageous concept provides that a plug-in cross-section of the plug-in receptacle is designed entirely or at least partially for the direct, form-fitting support of the coupling arm. For example, the at least one support surface produced by machining is machined such that it can directly support the coupling arm. As mentioned, the plug-in cross-section for the coupling arm can also be provided at least partially or entirely by the receiving sleeve or a receiving sleeve arranged in the coupling arm receptacle. However, it is also possible for a receiving sleeve to be arranged in the coupling arm receptacle for receiving the coupling arm, wherein a particularly polygonal inner circumferential contour of the receiving sleeve provides a plug-in cross-section for the form-fitting circumferential holding of the coupling arm. The receiving sleeve has an insertion opening for inserting the coupling arm.

[0047] The receiving sleeve is designed, for example, as a tubular body.

[0048] The plug-in sleeve advantageously has a reinforcing bead or collar in the area of ​​the insertion opening. The collar or reinforcing bead preferably extends in a ring shape around the insertion opening.

[0049] The receiving sleeve is advantageously open on its side opposite the insertion opening, although alternatively a bottom can also be provided there, ie the receiving sleeve is only open at the insertion opening, but otherwise closed.

[0050] It is advantageous if the receiving sleeve has a polygonal outer peripheral contour that is positively received in a polygonal inner peripheral contour of the coupling arm holder. For example, the outer peripheral contour and the inner peripheral contour are rectangular, in particular square. It is possible for corner areas or edge regions to be rounded, both on the inner peripheral contour and / or on the outer peripheral contour.

[0051] It's possible that the mounting sleeve doesn't protrude in front of the clutch arm mount on at least one side. However, it's also possible that the mounting sleeve protrudes in front of the clutch arm mount and / or behind the clutch arm mount with respect to the thru axle.

[0052] At this point, it becomes clear that the receiving sleeve allows for optimal adaptation of the plug-in socket for the clutch arm. This means that, for example, the clutch arm socket can be shorter than the receiving sleeve. Thus, it is possible for the plug-in socket, which supports the clutch arm when inserted into the clutch arm socket, to have a greater length relative to the plug-in axis than the clutch arm socket itself, thanks to the receiving sleeve.

[0053] The arrangement or design of a locking mechanism for the coupling arm in or on the coupling arm holder is also made more flexible by the holder sleeve, which will become clear below.

[0054] Advantageously, at least one locking receptacle, in particular a pair of opposing locking receptacles, is arranged on the receiving section for receiving a locking element, in particular a locking bolt, for locking the coupling arm. For example, the at least one locking receptacle is a bore, in particular a through-opening. The locking element preferably forms a component of the trailer coupling.

[0055] It is possible for the at least one locking receptacle to be arranged directly on the coupling arm receptacle or on the receiving sleeve, or both. It can be provided that the at least one locking receptacle extends through the coupling arm receptacle and / or a receiving sleeve, or the receiving sleeve that is received in the coupling arm receptacle.

[0056] An advantageous concept provides for one or more eyelets for attaching breakaway cables or breakaway chains to be arranged on the coupling arm support. It is advantageous if the at least one eyelet is integral with the coupling arm support.

[0057] A breakaway cable or chain is used to secure the trailer to the tow bar and extends between the tow bar and the trailer when held on one of the aforementioned eyes.

[0058] It is preferred if the at least one eyelet is arranged on the receiving section. It is particularly advantageous if an eyelet for a breakaway cable is arranged on opposite sides of the receiving section and / or on opposite sides of the coupling arm receptacle.

[0059] The at least one eyelet, preferably all eyelets, preferably protrudes transversely to the plug-in axis in front of the receiving section.

[0060] The coupling arm support can be permanently fixed to the support base. For example, it is possible for the coupling arm support to be screwed, welded, or similarly connected to the support base.

[0061] However, it is advantageously provided that the coupling arm support is adjustable with respect to the holding base between a position of use intended for coupling the trailer or the rear load carrier and a non-use position intended for non-use of the trailer coupling.

[0062] For example, it is possible for the coupling arm support to be detachably fastened to the support base, for example by means of a plug-in connection. For example, the support base has a plug-in receptacle or is designed as a plug-in receptacle that can accommodate a plug-in projection of the coupling arm support or into which the plug-in projection can be inserted. For example, the support section is designed as a plug-in projection or has one.

[0063] However, it is also possible for the coupling arm support itself to remain on the support base, for example by means of a pivot bearing or a pivot-sliding bearing, one of the support bases is mounted between the use position and the non-use position.

[0064] For example, it can be provided that the holding section forms a bearing section and the holding base forms a bearing base, wherein the coupling arm support is pivotally mounted on the holding base about a pivot axis between the use position and the non-use position by means of the bearing section. At this point it should be mentioned that the coupling arm support can be pivotally mounted not only about the at least one pivot axis on the holding base, but can also be pivotable about, for example, two or further pivot axes relative to the holding base. A linear adjustment of the coupling arm support between the use position and the non-use position is also possible, for example superimposed on the pivoting movement about the at least one pivot axis or sequentially relative to the pivoting movement.It is therefore possible for the coupling arm support to be mounted on the support base between the use position and the non-use position using a multi-axis pivot bearing and / or a combined pivot-slide bearing.

[0065] The trailer coupling advantageously has a fixing device for stationary fixing of the coupling arm support in the use position and the non-use position relative to the support base, wherein the coupling arm support is movable between the use position and the non-use position in a release position of the fixing device relative to the support base and is stationary fixed in a fixing position of the fixing device relative to the support base. In the release position, the coupling arm support is, for example, removable from the support base and, in the fixing position, is stationary fixed to the support base. It is also possible for the coupling arm support to be mounted movable about a pivot axis and / or sliding axis relative to the support base in the release position, for example, to be pivotally mounted, and to be stationary fixed in the fixing position relative to the pivot axis or sliding axis.

[0066] Advantageously, form-locking contours are arranged on the holding base, and counter-form-locking contours are arranged on the coupling arm support, forming a component of the fixing device. In particular, the counter-form-locking contours are integral components of the coupling arm support. The counter-form-locking contours are arranged, for example, around a bearing receptacle or a projection of the holding section of the coupling arm support. The form-locking contours and the counter-form-locking contours can be brought into engagement with one another, for example, by a linear adjustment, in particular parallel to the pivot axis, whereby the fixing device assumes a fixing position and the coupling arm support is fixed in place with respect to the holding base, or can be brought out of engagement, whereby the fixing device assumes a release position and the coupling arm support is rotatable about the pivot axis with respect to the holding base.

[0067] Not only with a multi-part construction of the coupling arm support, but also with the one-piece variant of the coupling arm support, numerous geometric designs are possible in order to geometrically adapt the coupling arm support to the local conditions on the motor vehicle, in particular for pivoting between the use position and the non-use position, for storage in the non-use position on the motor vehicle or an optimal position of the coupling arm in the use position.

[0068] Advantageously, the plug-in axis of the coupling arm mount and a bearing axis of a bearing mount, which is pivotally engaged with the support base, are angled to each other. Thus, for example, the pivot axis can be inclined at an angle other than 90° with respect to the longitudinal direction of the motor vehicle and / or with respect to a cross member on which the support base is arranged.

[0069] Advantageously, the bearing mount is designed as a bore produced by a drilling or milling tool. The bore can also be a stepped bore, i.e., have multiple diameters.

[0070] The coupling arm comprises, for example, a tubular body or arm body, at the free end of which a coupling body, in particular a coupling ball, is arranged. The coupling body can, for example, be screwed to the arm body. This makes it possible to attach various coupling body designs to the arm body. The coupling body and the insertion section for insertion into the coupling arm receptacle are advantageously arranged at opposite longitudinal end regions of the arm body.

[0071] The arm body preferably has a locking receptacle, for example a through-hole, for receiving the locking element. The locking receptacle is aligned with the locking receptacles of the coupling arm receptacle or the receiving sleeve when the arm body or the coupling arm is inserted into the coupling arm receptacle or receiving sleeve.

[0072] The coupling arm advantageously forms a component of the trailer coupling. It is also possible to use other coupling arms on the coupling arm support that are not part of the trailer coupling according to the invention, provided that their plug-in sections for insertion into the coupling arm receptacle have an outer peripheral contour that matches the inner peripheral contour of the coupling arm receptacle.

[0073] It is also possible for the coupling arm to be a component of a load carrier, for example a bicycle carrier, which can be inserted into the coupling arm receptacle when the coupling arm carrier is in the position of use.

[0074] The trailer coupling advantageously comprises a support assembly for attachment to a body of the motor vehicle. The support assembly comprises a cross member that can be connected to the body of the motor vehicle by means of side supports. The support base is advantageously attached to the vehicle mount or is provided by the vehicle mount. The vehicle mount is advantageously held to the support assembly.

[0075] An advantageous concept or independent invention provides that the holding base or a holding base provided and designed to hold a coupling arm is held on a support element of the support arrangement, for example on a cross member, by means of at least one mounting plate or at least one mounting plate or at least one holding flange, wherein the at least one mounting plate or the at least one mounting plate or the holding flange and the holding base are connected to one another by means of a plug weld. The support arrangement serves to fasten the trailer coupling to a motor vehicle, in particular to a rear of a motor vehicle and / or to a body of the motor vehicle. The holding base is designed, for example, as a tubular body which has a plug-in receptacle for inserting the coupling arm support or a coupling arm.In any case, this essentially independent invention provides that a coupling arm is detachably attachable to the support base, or the coupling arm is fixedly held to the support element of the support assembly by means of the support base. However, the support base can also form a bearing base for the movable, in particular pivotable, support of the coupling arm or a coupling arm support, to which the coupling arm is detachably attachable or fixedly arranged. The coupling arm support can integrally comprise the coupling arm.

[0076] In this case, a hole containing and / or enabling the plug weld is provided on a part of the support base or mounting plate or support flange, on the inner circumference of which a weld is provided between this one part with the hole and the other part of the support base or mounting plate or support flange. It is particularly advantageous if a hole is provided on the mounting plate or mounting plate, on the inner circumference of which a weld seam or other material connection is provided between the mounting plate or mounting plate on the one hand and the support base on the other.

[0077] Advantageously, the hole has at least one pointed or narrower end region. It can be provided that the hole has opposing pointed or narrower end regions. However, it is also possible for the hole to be approximately triangular, for example. In this embodiment, it is possible for only a single pointed or narrower end region to be present. The pointed or narrower end region of the hole advantageously increases the strength of the connection between the two components connected by means of the plug weld.

[0078] A transverse width of the hole is preferably smaller than a longitudinal height of the hole, wherein the transverse width and the longitudinal height are orthogonal to each other.

[0079] The narrower or pointed end regions are preferably provided at the ends of the hole in relation to the longitudinal height.

[0080] With regard to the transverse width, it is advantageous if the inner circumference of the hole in the area of ​​its maximum transverse width has flatter angles or curves with larger radii than the inner circumference of the hole in the area of ​​its maximum longitudinal height.

[0081] The hole preferably has its maximum longitudinal extension or longitudinal height parallel to a longitudinal extension of the support base. The longitudinal extension of the support base is the direction in which the support base has its greatest extension in the contact area with the mounting plate or the mounting plate or the support flange. The longitudinal extension of the support base is preferably parallel to a plug-in axis or mounting plug-in axis, along which the coupling arm support can be inserted into a plug-in receptacle of the support base.

[0082] It is preferred if the hole has a non-circular or oval shape.

[0083] It is advantageous that the hole is approximately diamond-shaped.

[0084] Furthermore, it is advantageous if the mounting plate, mounting plate, or retaining flange have legs that are angled to one another. The mounting plate, mounting plate, or retaining flange can also have no angle and / or extend in a single plane and / or have a flat shape. The hole for the plug weld can be located on only one of these legs. However, it is also possible for the hole to extend over an angled section across both legs of the mounting plate, mounting plate, or retaining flange.

[0085] It is advantageous that the welding is provided on the entire or substantially entire inner circumference of the hole in the transition area.

[0086] Exemplary embodiments of the invention are explained below with reference to the drawings. They show:

[0087] Figure 1 is a perspective oblique view of a trailer coupling from the rear,

[0088] Figure 2 shows the trailer coupling according to Figure 1 in perspective view, but from an opposite side to the view according to Figure 1,

[0089] Figure 3 shows a coupling arm support of the trailer coupling according to the preceding figures with a coupling arm holder for a coupling arm in a perspective oblique view,

[0090] Figure 4 shows the coupling arm support according to Figure 3, but in a frontal view of the coupling arm holder,

[0091] Figure 5 shows a section through the coupling arm support according to Figure 4, approximately along a section line AA in Figure 4,

[0092] Figure 6 shows an alternative embodiment of the coupling arm support in a perspective oblique view, Figure 7 shows the coupling arm support according to Figure 6, also in a perspective oblique view, but with a receiving body for a coupling arm,

[0093] Figure 8 shows the coupling arm support according to Figure 6 in a frontal view,

[0094] Figure 9 shows the coupling arm support according to Figure 7 in a frontal view,

[0095] Figure 10 is a perspective oblique view of a holding base for the coupling arm supports according to the preceding figures with form-locking elements,

[0096] Figure 11 is a perspective oblique view of a holding section of the coupling arm support with counter-form-locking elements matching the form-locking elements of the holding base according to Figure 10,

[0097] Figure 12 is a sectional view of the trailer coupling according to the preceding figures, approximately along a section line CC in Figure 1,

[0098] Figure 13 is a perspective oblique view of a further embodiment of a trailer coupling, in which the holding base has a plug-in receptacle for inserting a plug-in projection of the coupling arm support, wherein the coupling arm is removed from the coupling arm support and the coupling arm support is removed from the holding base,

[0099] Figure 14 shows the trailer coupling according to Figure 13, but in a ready-to-use condition suitable for coupling a trailer,

[0100] Figure 15 shows a section through the coupling arm support according to Figure 13, approximately along a section line DD,

[0101] Figure 16 is a side view of the trailer coupling of Figures 13-15, Figure 17 is a partial front view of another coupling arm support after partial machining,

[0102] Figure 18 Coupling arm support according to Figure 17, but diagonally from the side,

[0103] Figure 19 shows the front view of the coupling arm support according to Figure 17, but complete and in operational condition, and

[0104] Figure 20 shows the coupling arm support according to Figure 19 in an oblique view corresponding to Figure 18.

[0105] A trailer coupling 10 is attached or attachable to a rear end 101 of a motor vehicle 100. The trailer coupling 10 advantageously comprises a support arrangement 90 with a cross member 91, which is attached or attachable to a body 102 of the motor vehicle 100, for example, a passenger car, an electric vehicle, or the like, by means of side supports 92. The side supports 92 comprise, for example, mounting plates 93, which can be attached to the body 102 by means of screws. Retaining arms 94, for example in the form of forks, protrude from the mounting plates 93 and hold the cross member 91.

[0106] A vehicle mount 95 for the trailer coupling 10 is arranged on the cross member 91. The vehicle mount 95 comprises, for example, support legs 96, to which a support base 11 of the trailer coupling 10 is fastened by means of screws 97. The support base 11 is held, for example, in a sandwich-like manner between the support legs 96. The support legs 96 are fastened to the cross member 91, for example, by welding. The support base 11 could also be fastened directly to the cross member 91, for example, by being screwed to the cross member 91 or the like.

[0107] The support base 11 pivotally supports a coupling arm support 50 about a pivot axis S between a use position G, which is provided for coupling, in particular for towing, a schematically illustrated trailer AH or coupling a schematically illustrated load carrier LT, and a non-use position N, which the coupling arm support 50 can assume when not in use, for example, when no trailer is to be towed. The non-use position N is shown in Figure 1 in dashed lines, the use position G in solid lines.

[0108] The holding base 11 thus forms, for example, a bearing base 11 A.

[0109] In the use position G, the coupling arm support 50 projects downwards in front of a bumper 103 of the motor vehicle 100, for example, so that a coupling arm 80 can be fastened to the coupling arm support 50. In the non-use position N, the coupling arm support 50 is adjusted, for example, closer to the body 102 of the motor vehicle 100, for example, behind and / or below the bumper 103. It may be necessary for the coupling arm 80 to be removed from the coupling arm support 50 before the coupling arm support 50 is adjusted from the use position G to the non-use position N. Depending on the spatial conditions on the motor vehicle 100, it is also possible for the coupling arm 80 to remain on the coupling arm support 50 when the coupling arm support 50 is adjusted to the non-use position N. Such a situation is indicated in dashed lines in Figure 1.

[0110] The holding base 11 comprises a connecting section 12, which is held between the holding legs 96 and screwed to them. A support section 13, which is designed, for example, in the manner of a plate, protrudes from the connecting section 12. A bearing body 14 protrudes from the support section 13. The bearing body 14 is held in a receptacle 16 of the holding base 11. For example, screw elements 17 and 18 are held on the receptacle 16, to which the bearing body 14 is held, for example by means of a screw connection.

[0111] The bearing body 14 is, for example, tubular. The bearing body 14 is, for example, a shaft body, in particular a hollow shaft. The coupling arm support 50 is rotatably mounted on the bearing body 14.

[0112] For example, the bearing body 14 engages in a bearing receptacle 54 of a holding section 53 of the coupling arm carrier 50.

[0113] The holding section 53 forms a bearing section 53A, which is pivotally mounted on the bearing base 11A about the pivot axis S.

[0114] The trailer coupling 10 has a fixing device 20 for fixing the coupling arm support 50 to the holding base 11 in the use position G and the non-use position N.

[0115] The fixing device 20 comprises, for example, form-locking elements 21 which are arranged on an end face 15 of the support section 13, and counter-form-locking elements 22 which are arranged on an end face 55 of the holding section 53 of the coupling arm carrier 50.

[0116] The form-locking elements 21 extend around the bearing body 14 and the counter-form-locking elements 22 extend around the bearing receptacle 54 of the coupling arm carrier 50.

[0117] By a linear adjustment of the coupling arm support 50 from the holding base 11 parallel to the pivot axis S, the form-locking elements 21 and the counter-form-locking elements 22 can be brought into engagement, so that the fixing device 20 assumes a fixing position F, or disengaged, so that the fixing device 20 assumes a release position L. In the fixing position F, the coupling arm support 50 is fixed in position with respect to the holding base 11; in the release position L, the coupling arm support 50 can be pivoted between the use position G and the non-use position N with respect to the holding base 11.

[0118] The form-locking elements 21 comprise, for example, form-locking receptacles 21A, 21B and 21C for the form-locking engagement of form-locking projections 22A, 22B and 22C of the counter-form-locking elements 22. In principle, it is possible for all form-locking elements 21 and counter-form-locking elements 22 to have the same geometries. In the present case, however, different geometries are provided such that the form-locking elements 21 and the counter-form-locking elements 22 only fit into one another in the use position G and the non-use position N. For example, the form-locking receptacles 21A and the form-locking projections 22A are spherical domes and balls, while the form-locking receptacles 21B and the form-locking projections 22B have a somewhat elongated shape, and finally, the form-locking receptacles 21C and the form-locking projections 22B have a longitudinal shape.

[0119] The fixing device 20 further comprises a fixing drive 23, with which the form-locking elements 21 and the counter-form-locking elements 22 can be disengaged and engaged. The fixing drive 23 thus actuates the coupling arm support 50 parallel to the pivot axis S between the fixing position F and the release position L.

[0120] The fixing drive 23 comprises a drive body 24, for example a bolt-like drive body, which is received in a guide channel 24A of the bearing body 14 so as to be linearly displaceable, in this case parallel to the pivot axis L.

[0121] The drive body 24 is loaded by a spring 25 into a position associated with the fixing position F, in which at least one actuating contour 26 of the drive body 24 actuates transmission bodies 27, for example balls, radially outwards with respect to the pivot axis S, through channels 27A running radially to the pivot axis S in the direction of an actuating contour 28 on a drive body 29, which is fixedly fixed to the coupling arm support 50, for example forms a fixed component thereof or is firmly connected thereto.

[0122] The actuating contours 26, 28 comprise, for example, one or more inclined surfaces, in particular extending in a ring shape around the pivot axis S, which cause a force deflection such that by a movement of the drive body 24 in a direction towards the coupling arm carrier 50, the coupling arm carrier 50 is loaded in a direction opposite thereto towards the holding base 11, so that the form-locking elements 21 and the counter-form-locking elements 22 engage with one another.

[0123] To release this positive locking between the positive locking elements 21 and the counter-positive locking elements 22, i.e. for actuation in the direction of the release position L, it is provided that the drive body 24 is or will be driven by a release drive 30, for example an electric motor, against the force of the spring 25 in a direction away from the coupling arm carrier 50, whereby the actuating contours 26 release the transmission bodies 27, so to speak, so that they can move into the channels 27A and thus release the coupling arm carrier 50 for movement away from the holding base 11.

[0124] Furthermore, at least one release actuation contour 31 is arranged on the drive body 24, which acts on transmission bodies 32, for example balls, which can be actuated radially outwards with respect to the pivot axis S through channels 33 by means of the at least one release actuation contour 31 in order to be able to act on at least one counter contour 34 which is arranged on the drive body 29 of the coupling arm carrier 50 and, when subjected to force by the transmission bodies 32, causes the coupling arm carrier 50 to be adjusted in the direction of the release position L.

[0125] The drive body 29 is accommodated, for example, in a receptacle 51 of the coupling arm carrier 50, which forms part of the bearing receptacle 54 or is arranged next to it.

[0126] Advantageously, the drive body 29 is positively received in the receptacle 51.

[0127] Advantageously, the drive body 29 is pressed into the holder 51.

[0128] It is advantageous if the drive body 29 is held firmly in the receptacle 51, for example, by being glued and / or welded. The drive body 29 is, for example, sleeve-shaped. The actuating contour 28 and the counter contour 34 can, for example, be opposite inclined surfaces, in particular annular inclined surfaces.

[0129] The drive body 29 has a bearing opening or bearing receptacle 35, in particular a through-opening, for the bearing body 14, for example the hollow shaft, so that the drive body 29 is mounted on the bearing body 14 so as to be rotatable about the pivot axis S and displaceable parallel to the pivot axis S. The bearing body 14 engages in the bearing receptacle 35.

[0130] The holding section 53 comprises, for example, or is formed by a bearing body 52. ​​The bearing receptacle 54, the receptacle 51, and the end face 55 with the counter-form-locking elements 22 are provided on the bearing body 52.

[0131] An arm section 56 protrudes from the holding section 53 of the coupling arm support 50.

[0132] The arm section 56 is designed to be straight, although curvatures are readily possible. The arm section 56 extends along a longitudinal axis L56.

[0133] The arm section 56 is short, ie a longitudinal extension of the arm section 56 along the longitudinal axis L56 is smaller than a longitudinal extension of the coupling arm receptacle 60 parallel to the plug-in axis K.

[0134] The arm portion 56 includes an arm body 57 integral with the holding portion 53. The arm body 57 and the bearing body 52 are integral.

[0135] The arm body 57 preferably has ribs 58.

[0136] In principle, it is possible for an opening to be present on the arm body 57 between the ribs 58. Thus, for example, two separate arm bodies 57A, 57B are present, which connect the holding section 53 to the receiving section 59, as indicated in Figure 6.

[0137] The arm body 57 is preferably a solid arm body. A cross-sectional contour of the arm body 57 is preferably rectangular or square. At least one envelope, which also encloses the ribs 58, advantageously has a rectangular or approximately square cross-section.

[0138] On the arm section 56 there is a receiving section 59 with a

[0139] Coupling arm holder 60 is arranged. The coupling arm holder 60 serves to accommodate a coupling arm 80, which is intended for coupling the trailer AH or attaching the load carrier LT.

[0140] The coupling arm 80 can be inserted into the coupling arm holder 60 along a plug-in axis K.

[0141] The coupling arm 80 comprises, for example, an arm body 81, at one longitudinal end region of which a coupling body 82, for example a coupling ball, is arranged and the other longitudinal end region of which provides a plug-in section 83 for insertion into the coupling arm receptacle 60.

[0142] The coupling body 82 has, for example, a screw section 84 which passes through a through-opening of the arm body 81, not visible in the drawing, wherein a nut 85 is screwed onto a part of the screw section 84 which projects in front of the arm body 81.

[0143] The coupling arm receptacle 60 has a substantially rectangular inner circumferential contour 61, which is defined by opposing support surfaces 62 and by support surfaces 63 that are angled to these support surfaces 62 and also opposite one another.

[0144] Two of the support surfaces 62 and 63 are perpendicular to each other, so that they can provide form-fitting, flat support for a polygonal outer peripheral contour 86 of the plug-in section 83 of the arm body 81. The coupling arm 80 can be inserted into the coupling arm receptacle 60 through an insertion opening 66. The coupling arm receptacle 60 forms a plug-in receptacle 60A.

[0145] The coupling arm receptacle 60 has a further opening 67 on its side opposite the insertion opening 66 through which the arm body 81 can protrude.

[0146] The coupling arm receptacle 60 is provided on a tubular body 70, whose upper wall 72 is connected to the arm body 57 and opposite which is a lower wall 73. The walls 72 and 73 are connected to each other by side walls 71. The insertion opening 66 is provided on one end face of the tubular body 70. A front wall surface 74 extends around the insertion opening 66.

[0147] The coupling arm receptacle 60 further comprises locking receptacles 68 through which a locking element 40 can be inserted. The locking receptacles 68 are provided, for example, on the side walls 71.

[0148] The locking element 40 has a locking section 41 in the form of a locking bolt, which can be actuated using a handle 42 of the locking element 40 that is angled to the locking section 41. The coupling arm 80 has locking receptacles that are aligned with the locking receptacles 68, which are not visible in the drawing and through which the locking element 40 can be pushed with its locking section 41 when the coupling arm 80 is received in the coupling arm receptacle 60. The locking element 40 can be secured using a securing element 43, for example a securing clasp, which can be inserted into a corresponding securing opening in the locking element 40, when it locks the coupling arm 80 to the coupling arm receptacle 60.

[0149] The coupling arm support 50 further comprises eyelets formed integrally thereon

[0150] 75 for breakaway cables or breakaway chains or similar flexible securing devices. The eyelets 75 protrude laterally from the side walls 71 and have a bore or through-opening 76. The bores or through-openings 76 extend at an angle, in particular perpendicular, to the walls 72 and 73. Advantageously, the eyelets 75 are located close to the upper wall 72 and approximately flush with it, so that they are easily accessible to a user of the trailer coupling 10.

[0151] The support surfaces 62 and 63 are machined. The support surfaces 62 and 63 are, for example, optimally flat surfaces, which is made possible by the machining. Thus, the support surfaces 62 and 63 can optimally support the coupling arm 80 when it is inserted into the coupling arm receptacle.

[0152] The clutch arm support 50 is manufactured from the blank 150. The blank 150 already has the basic circumferential contour of the clutch arm support 50. The blank 150 is manufactured, for example, as a cast part.

[0153] It is preferred if the blank 150 is manufactured as a forged part. The drawing shows forging tools S1 and S2, which form the blank 150 from a raw material. Movements of the forging tools S1 and S2 toward or away from the blank 150 are indicated by double arrows SB.

[0154] The blank 150 does not yet have a bore or through-hole for the bearing support 54. The bearing support 54 is manufactured, for example, using a drilling tool BWZ. Of course, another drilling tool can be used to produce the support 51, which is not shown in the drawing for reasons of simplicity. It is also possible for the drilling tool BWZ to be designed as a step drill in order to produce the support 51 and the bearing support 54 in a single drilling process.

[0155] Between each support surface 62 and an adjacent support surface 63 angled to this support surface 62, an inner corner region 64 is provided, which defines a receiving cavity 65. The receiving cavity 65 is preferably designed as an inner corner region or as a recess in an inner corner region.

[0156] For example, the receiving cavity 65 can be designed as a recess opposite an envelope of an inner corner.

[0157] The receiving cavities 65 can, for example, facilitate the removal of a forging tool or a casting core.

[0158] The receiving cavities 65 facilitate, for example, the machining of a blank 150 of the coupling arm carrier 50 by a cutting tool SW2, which is or is used to produce the support surfaces 62 and 63.

[0159] The forging tools S1 and S2 have projections V1 and V2, which are used to produce the so-called raw clutch arm holder 60, hereinafter referred to as clutch arm holder 160. The clutch arm holder 160 has a raw basic contour or raw contour 161.

[0160] The projections V1 and V2 have, for example, the shape of a truncated pyramid, i.e., they have gently inclined side walls to enable demolding or removal of the projections V1 and V2 from the coupling arm receptacle 160. This creates, so to speak, raw and likewise inclined partial support surfaces 162A and 163A from the side of the insertion opening 66, as well as raw and likewise inclined partial support surfaces 162B and 163B from the opening 67, from which the support surfaces 62 and 63 are produced using the tool SW2. The raw partial support surfaces 162A and 163A and the partial support surfaces 162B and 163B are inclined in the sense of a narrowing toward a central region 164 of the coupling arm receptacle 160.

[0161] In the central region 164, a wall 164A initially remains after the removal of the forging tools S1 and S2. This wall is then removed by a drilling tool, milling tool, or spinning tool before the machining described below begins using the tool SW2. The receiving cavities 65 can taper conically toward the central region 164.

[0162] The tool SW2, for example, is a broaching tool with a longitudinal shape. The tool SW2 is pushed and / or pulled from the insertion opening 66 through the raw coupling arm receptacle 160 with a feed movement SBB oriented in the direction of a longitudinal axis of the tool SW2. The broaching tool or tool SW2 has a great length, for example, 2 m or 3 m.

[0163] The tool SW2 or broaching tool has, for example, an elongated truncated pyramid-like and / or conical pre-machining area SWV, e.g. designed as a truncated pyramid with rounded corner areas, which has at its one longitudinal end area, which is initially introduced into the coupling arm receptacle 60, distances D1 between mutually opposite sides provided for producing mutually opposite support surfaces 62 or 63, which increase along the pre-machining area SWV in the direction of a machining area SWE up to distances D2 which the machining area SWE has between mutually opposite sides provided for producing mutually opposite support surfaces 62 or 63.The machining area SWE is intended for the final machining or finishing of the coupling receptacle 60 and has constant distances D2 over its entire length, which is passed through the coupling arm receptacle 60.

[0164] The tool SW2 has a toothing SWZ, which in the pre-machining area SWV rises diagonally according to the oblique course of the respective longitudinal sides of the tool SW2 and increasingly machines the partial support surfaces 162A, 163A, 162B, 163B until they have the planned dimensions required for the support surfaces 62 and 63. In the machining area SWE, the teeth on the longitudinal sides of the tool SW2 no longer rise, but protrude at the same height in front of the respective longitudinal sides, so that the support surfaces 62 and 63 have the same distances from one another over their entire longitudinal length in the area of ​​the coupling arm holder 60.

[0165] Figure 5 schematically shows an enlargement AVG of a part of the toothing SWZ, from which the increase in the toothing in the pre-machining area SWV as well as the constant height of the toothing in the machining area SWE can be seen.

[0166] Furthermore, it is advantageously provided that the front wall surface 74 is machined, for example, ground or milled, so that it is formed as a flat surface. Thus, the front wall surface 74 can, for example, also form a support surface for a collar of a receiving sleeve received in the coupling arm receptacle 60, which will become clearer below.

[0167] Furthermore, it is possible for a collar or projection (not shown in the drawing) to be provided on the coupling arm 80, which can abut against the front wall surface 74 of the coupling arm receptacle 60, ie for the front wall surface 74 to form, for example, a dimensionally accurate stop for the coupling arm 80.

[0168] The production of the support surfaces 62 and 63 by machining also improves the hold of a receiving sleeve 260, which can be received in the coupling arm receptacle 60 and into which the coupling arm 80 can be inserted. Such a design is provided for the coupling arm carrier 250. The coupling arm carrier 250 basically corresponds to the coupling arm carrier 50. However, it is possible for the inner circumferential contour 61 of the coupling arm carrier 52 to be somewhat larger in order to be able to accommodate the receiving sleeve 260. The machining for producing the support surfaces 62 and 63 is identical, however, which is why, for the sake of simplicity, they are referred to as support surfaces 62 and 63, even if their dimensions may differ from those of the coupling arm carrier 50.

[0169] The receiving sleeve 260 comprises, for example, a tubular body 270 whose side walls 271 are connected to each other by an upper wall 272 and a lower wall 273. Outer sides of the walls 271, 272, 273 form an outer peripheral contour 275, which is positively received in the inner peripheral contour 61 of the coupling arm receptacle 60.

[0170] The receiving sleeve 260 projects on opposite sides in front of the coupling arm receptacle 60 and has an insertion opening 266 for inserting the coupling arm 80, which can project on a side opposite the insertion opening 266 in front of an opening 267 of the receiving sleeve 260.

[0171] Longitudinal positions of the receiving sleeve 260 relative to the longitudinal axis of the coupling arm receptacle 60 are selectable, i.e., the receiving sleeve 260 may, for example, not protrude beyond one of the openings 66 or 67, or may protrude beyond these openings by varying amounts. In any case, the extent to which the receiving sleeve 260 protrudes beyond the opening 67 of the coupling arm receptacle 60 or beyond the insertion opening 66 of the coupling arm receptacle 60 can be selected as required. The only essential requirement is that the receiving sleeve 260 is firmly received in the coupling arm receptacle 60, for which the flat support surfaces 62 and 63, which accordingly provide good support for the receiving sleeve 260, provide an optimal basis.

[0172] By using a receiving sleeve, for example, the receiving sleeve 260, it is also possible to select a different locking arrangement than in the coupling arm support 50, in which the locking receptacles 68 are arranged directly on the coupling arm receptacle 60. For example, the receiving sleeve 260 can have locking receptacles 268 provided on the side walls 271 on sections of the side walls 271 that protrude in front of the insertion opening 66.

[0173] The receiving sleeve 260 has, for example, a collar-like bead 269 at its insertion opening 266, which reinforces the receiving sleeve 260.

[0174] Furthermore, the receiving sleeve 260 has, for example, a flange-like projection 277, which can abut against the front wall surface 74 of the coupling arm receptacle 60. However, it is also possible that the reference numeral 277 denotes a weld seam with which the receiving sleeve 260 is welded to the coupling arm support 250.

[0175] A trailer coupling 310 according to Figures 13-15 has a coupling arm support 350, which, like the coupling arm support 50, has a receiving section 59 with a coupling arm receptacle 60, which is manufactured according to one or more of the methods already explained. Thus, the coupling arm receptacle 60 is manufactured by machining.

[0176] In contrast to the previous embodiments, however, a holding base 311 of the trailer coupling 310, which is fastened or can be fastened to the motor vehicle 100, is provided to releasably fasten the coupling arm support 350, so that the coupling arm support 350 assumes a position remote from the holding base 311 when not in use or in a non-use position N, for example it can be stowed in the luggage compartment of the motor vehicle 100.

[0177] For example, the holding base 311 has a receiving body 312 for receiving and holding a holding section 353 of the coupling arm support 350. The holding section 353 is designed, for example, as a plug-in projection 354 or has a plug-in projection 354 that is provided for insertion into a plug-in receptacle 314 of the holding base 311. The plug-in receptacle 314 is provided, for example, on the receiving body 312. However, during use or in a use position G, the coupling arm support 350 is fastened to the holding base 311, for example by inserting the plug-in projection 354 into the plug-in receptacle 314.

[0178] A fixing device 320 is used to fix the coupling arm support 350 to the holding base 311. The fixing device 320 comprises form-locking elements 321 arranged on the holding base 311, for example form-locking receptacles, into which counter-form-locking elements 322 of the coupling arm support 350, for example form-locking projections, engage in a fixing position F of the fixing device 320 when the plug-in projection 354 is inserted into the plug-in receptacle 314. For example, the form-locking receptacles and form-locking projections are triangular or wedge-shaped contours that are arranged laterally on the receiving body 312, which is designed, for example, as a plug-in sleeve, or on the coupling arm support 350.

[0179] Furthermore, the fixing device 320 comprises a fixing drive 323 with a drive body 324, which is located in a guide channel 24A extending in the plug-in projection 354 and is biased by a spring 325 into a fixing position F of the fixing device 320, in which the fixing device 320 fixes or locks the coupling arm support 350 to the holding base 311. The drive body 324 serves to actuate form-fitting bodies 327, configured, for example, as a ball, through channels 327A in the direction of a receiving contour 328, for example, an annular groove in the plug-in receptacle 314. When the form-locking bodies 327 engage the receiving contour 328, the plug-in projection 354 is locked in the plug-in receptacle 314 with respect to an assembly plug-in axis MS, along which the plug-in projection 354 can be inserted into or removed from the plug-in receptacle 314. The form-locking elements 321, 322 can then no longer disengage.

[0180] A release drive 330 is used to release the positive connection between the positive-locking bodies 327 and the receiving contour 328. The release drive 330 comprises a handwheel 331, with which a gear 332 can be actuated, wherein the gear 332 meshes with a rack section 333 that forms part of the drive body 324 or is connected thereto. Thus, by turning the handwheel 331, an operator can move the drive body 324 away from the channels 327A against the force of the spring 325 such that the positive-locking bodies 327 can move into the channels 327A and thus disengage from the receiving contour 328. An arm section 356 protrudes from the holding section 353 of the coupling arm carrier 350. The arm portion 356 is substantially shorter than the arm portion 56 of the coupling arm support 50 of the trailer coupling 10. The arm portion 356 is configured, for example, as an arcuate portion or curved portion.The coupling arm support 350 can also be understood such that the holding section 353 is arranged directly on the coupling arm receptacle 60.

[0181] In contrast to the coupling arm support 50, the coupling arm support 350 has eyelets 375 arranged on a side of the receiving section 59 facing away from the holding section 353 or opposite the holding section 353. For example, in a use position of the coupling arm support 350, which is suitable for attaching a trailer or a load carrier, the eyelets 375 protrude toward a road surface and / or downward in front of the receiving section 59. The eyelets 375 have through-openings or bores 376 through which a breakaway cable, a breakaway cable, a hook, or other fastening element of a breakaway chain or a breakaway cable, or the like, can be passed. The eyelets 375 are designed as a pair of eyelets, wherein it is advantageously provided that the through-openings or bores 376 are opposite one another and / or aligned with one another.

[0182] Furthermore, the trailer coupling 310 comprises a coupling arm 380, wherein the coupling arm 80 can also be easily inserted into the coupling arm receptacle 60 of the coupling arm support 350. The coupling arm 380 comprises a coupling body 82 in the form of, for example, a coupling ball, as well as a plug-in section 83 that can be inserted into the coupling arm receptacle 60. An arm body 381 of the coupling arm 380 is designed, for example, as a profile tube, but fulfills the same basic function as the arm body 81.

[0183] For locking the coupling arm 380 to the coupling arm receptacle 60 of the coupling arm support 350, for example, the locking element 40 already explained is used, which can be pushed through the locking receptacles 68 and the locking receptacles 88 on the coupling arm 380 that are aligned therewith when the coupling arm 380 is inserted into the coupling arm receptacle 60 in the use position G.

[0184] The trailer coupling 310 comprises a support assembly 390 with a cross member 391, which can be attached, for example, to the rear 101 of a body 102 in the same way as the cross member 91, for example using side supports not visible in the drawing. The support base 311 is held on the support assembly 390.

[0185] The cross member 391 is designed, for example, as a round tube or profile tube.

[0186] A vehicle mount 395 with mounting plates 393 is attached to the cross member 391. The mounting plates 393 can also be referred to as retaining flanges or mounting flanges.

[0187] The mounting plates 393 have, for example, through-openings 394 through which the cross member 391 passes. The through-openings 394 are designed, for example, in the manner of retaining eyes. The cross member 391 and the mounting plates 393 are advantageously welded together in the region of the through-openings 394.

[0188] The mounting plates 393 hold the holding base 311. For example, the holding base 311 is sandwiched between the mounting plates 393.

[0189] The mounting plates 393 each have retaining legs 396A on which the through-openings 394 are arranged. Furthermore, the mounting plates 393 have fastening legs 396B angled to the retaining legs 396A.

[0190] Holes 397 are provided on the mounting plates 393, extending into the support legs 396A and the fastening legs 396B. An inner periphery of the holes 397 is in contact with the outer periphery of the support base 311, for example, the receiving sleeve for the coupling arm support 350. A weld, a so-called plug weld, is provided on the inner periphery of the holes 397. Thus, a bottom of the holes 397 is, so to speak, closed by the support base 311, forming a type of large-area blind hole.

[0191] It is particularly advantageous for the holes 397 to have an oval or elongated or diamond-shaped configuration such that they have pointed or narrow end regions 398 close to the cross member 391 and / or close to the free end region of the receiving sleeve or holding base 311 facing away from the cross member 391. This allows for particularly high strength.

[0192] The holes 397 advantageously extend over an angular range between a holding leg 396A and a fastening leg 396B of a mounting plate 393. However, the holes 397 could also be arranged only on a respective holding leg 396A or on a fastening leg 396B, i.e., they could not extend over both legs.

[0193] One leg of holding leg 396A or fastening leg 396B can rest flatly or evenly against an outer side of the holding base 311 or be aligned with it. However, it is also possible for both legs, i.e., holding leg 396A and fastening leg 396B, to be angled to the outer side of the holding base 311, i.e., neither of the two legs rests flatly against the holding base 311.

[0194] On one of the mounting plates 393, a fastening base 399 is advantageously arranged for fastening a trailer socket (not shown in the drawing) for supplying electrical power to a load carrier or trailer.

[0195] In an embodiment of a coupling arm support 450 shown in Figures 17-20, those components and functional elements which have already been described in connection with the coupling arm supports 50, 250, 350 are provided with reference numerals which have also been used for the description of the coupling arm supports 50, 250 and 350.

[0196] In contrast to the coupling arm supports 50, 250, 350, however, the coupling arm support 450 has a receiving section 459 that is manufactured differently than the receiving sections 59 and 259. In the finished state, which is shown in Figures 19 and 20, the receiving section 459 comprises the coupling arm receptacle 60, namely a plug-in receptacle 60A, which is designed for inserting the coupling arm 80.

[0197] Accordingly, the locking receptacles 68 are provided on a tubular body 470 of the receiving section 459, which serve to lock the coupling arm 80 when it is inserted from the insertion opening 66 into the plug-in receptacle 60A, in order to lock and / or secure the use position G.

[0198] The tubular body 470 has side walls 471 extending between an upper wall 472 and a lower wall 473. A front wall surface 474 at the insertion opening 66, which thus extends around the insertion opening 66, is designed as a flat surface and a surface produced by machining.

[0199] Eyelets 475 extend from the lower wall 473 and are designed similarly to the eyelets 375.

[0200] The eyelets 475 are arranged in pairs, with their through-openings or bores 476 facing each other and aligned with each other. In the use state or in the use position G, when the coupling arm support 450 is oriented for inserting the coupling arm 80 and thus for attaching a trailer or securing a load carrier, the eyelets 475 protrude downward from the receiving portion 459 toward a road surface. The eyelets 475 are thus arranged on a side of the coupling arm support 450 opposite the arm body 57.

[0201] The arm body 57 extends between the receiving portion 459 and the bearing body 52 or holding portion 53, which has already been described.

[0202] In contrast to the previously described coupling arm holders 60, the coupling arm holder 60 of the coupling arm support 450 is manufactured using the cutting tool SW2 and an additional cutting tool SW1.

[0203] In contrast to the coupling arm receptacle 60 of the coupling arm carrier 50, no receiving cavities 65 are provided on the inner corner regions 64, because the machining explained below using the cutting tool SW1, which precedes the machining by the tool SW2 and in which a raw coupling arm receptacle 460 is produced, allows the cutting tool SW2 to be easily inserted into the raw coupling arm receptacle 460 from the insertion opening 66.

[0204] As already explained, the use of forging tools S1 and S2, possibly also the use of similarly shaped casting cores or casting tools, results in the raw inner circumferential contour or raw contour 161 with the obliquely inclined raw partial support surfaces 162A, 163A as well as 162B and 163B. These may initially not be suitable for directly inserting the cutting tool SW2, namely, for example, a broach, into the insertion opening 66 in order to machine the coupling arm receptacle 60 and / or the at least one support surface 62 and / or 63.

[0205] In order to enable the insertion of the tool SW2, the raw inner circumferential contour or raw contour 161 is first pre-machined using a tool SW1, for example a milling tool and / or a drilling tool, whereby recesses 462 and 463 are created on the raw partial support surfaces 162A, 163A as well as 162B and 163B. The tool SW1 is, for example, rotationally driven (arrow RO) and is adjusted, for example, in the raw contour 161 by a positioning drive (indicated by arrows PX) such that the recesses 462, 463 are produced, whereby an outer circumference of the tool SW1 engages in the raw contour 161 in a machining manner, for example by milling it. The recesses 462, 463 are, for example, trough-shaped and extend into the partial support surfaces 162A, 163A, 162B, 163B.For example, a bottom of a respective recess 462, 463 is close to the contour of a support surface 62, 63 to be produced thereon or has only relatively little material compared to such a support surface 62, 63 produced later, e.g. by machining.

[0206] The recesses 462, 463 form an envelope of a basic contour 461, which is, for example, an approximately circular contour or at least forms such an inner circumferential contour.

[0207] The basic contour 461 produced by machining using the tool SW1 makes it possible to insert a front section SW2V of the tool SW2 into the insertion opening 66 in order to finally form the coupling arm holder 60, in particular to form the support surfaces 62, 63 as flat surfaces.

[0208] During the feed movement SBB of the tool SW2 into the insertion opening 66, the areas surrounding the recesses 462, 463 are successively removed in the direction of the inner corner regions 64, i.e., starting from a respective recess 462, 463, the flat surfaces 62, 63 are produced by machining, with material also being removed from raw inner corner regions 464 of the raw contour 161 in order to form the inner corner regions 64. The pre-machining region SWV of the tool SW2 can also be involved in this production of the inner corner regions 64 and the support surfaces 62, 63. In any case, the machining region SWE, which represents a final machining region, so to speak, creates an inner circumferential contour 61 extending from the insertion opening 66 to the rear opening 67, in which the support surfaces 62 lie parallel to one another and the support surfaces 63 lie parallel to one another.

[0209] The tool SW1 thus forms a first machining tool, and the tool SW2 forms a second machining tool. Starting with the forging tool or forging tools S1 and S2, a first rough contour or basic contour 161 is initially created, from which a further rough contour or second basic contour 461 is produced by using the first machining tool SW1. This second basic contour 461 is then formed into the final inner circumferential contour 61 of the coupling arm holder 60 by using the second machining tool SW2.

[0210] The oblique or conical shape of the raw partial support surfaces 162A, 163A and 162B, 163B can be seen in Figure 18, for example, in that the recesses 462, 463, which are produced by the first cutting tool SW1, for example a milling tool, have a smaller width in the area of ​​the insertion opening 66 with respect to the insertion axis K or feed axis, i.e. for example the longitudinal axis of the coupling arm holder 60, than in the area of ​​the longitudinal center or the central area 164.

[0211] The first cutting tool SW1, for example, has a round or rounded outer circumferential contour AUK1 to produce the rough contour 461. The second tool SW2, for example the broach, has an outer circumferential contour AUK2 that differs from the outer circumferential contour AUK1. For example, the outer circumferential contour AUK2 is essentially rectangular or square. In particular, the second outer circumferential contour in the finishing area SWE is suitable for directly producing the opposing planes and flat support surfaces 62-62 and 63-63.

Claims

Claims 1 . Trailer coupling for a motor vehicle (100) for coupling a trailer (AH) or a rear load carrier (LT), with a vehicle mounting (95) which is fastenable or fastened to the motor vehicle (100) and which has a holding base (11) on which a coupling arm support (50; 250; 350; 450) is held by a holding section (53; 353) at least in a position of use (G) provided for coupling the trailer (AH) or the rear load carrier (LT), wherein on the holding section (53; 353) of the coupling arm support (50; 250; 350;450) a receiving section (59) with a coupling arm receptacle (60) for receiving a coupling arm (80), which in particular forms a component of the trailer coupling (10), is arranged at least in the use position (G), wherein the coupling arm receptacle (60) is designed as a plug-in receptacle (60A) with an insertion opening (66) through which the coupling arm (80) can be inserted into the coupling arm receptacle (60) along a plug-in axis (K), at least in the use position (G), and is ready for coupling the trailer (AH) or rear load carrier (LT), characterized in that the coupling arm receptacle (60) has at least one support surface (62, 63) produced by machining for supporting the coupling arm (80).

2. Trailer coupling according to claim 1, characterized in that the holding section (53; 353) of the coupling arm support (50; 250; 350; 450) pivotally mounted on the holding base (11) and the receiving section (59) of the coupling arm support (50; 250; 350; 450) having the coupling arm receptacle (60) are in one piece.

3. Trailer coupling according to claim 1 or 2, characterized in that the coupling arm support (50; 250; 350; 450) is a forged part or a cast part.

4. Trailer coupling according to one of the preceding claims, characterized in that the coupling arm receptacle (60) has a polygonal cross-section with mutually angled support surfaces (62, 63) for the coupling arm (80), wherein at least one support surface (62, 63) for supporting the coupling arm (80), preferably all support surfaces (62, 63), are machined.

5. Trailer coupling according to one of the preceding claims, characterized in that at least one support surface (62, 63) or all support surfaces (62, 63) are designed as flat surfaces.

6. Trailer coupling according to one of the preceding claims, characterized in that a distance between opposing support surfaces (62, 63) along a plug-in section of the coupling arm receptacle (60) extending along the plug-in axis (K) is constant, wherein the coupling arm can be plugged into the plug-in section of the coupling arm receptacle (60).

7. Trailer coupling according to one of the preceding claims, characterized in that at least one corner region, in particular inner corner region (64), between mutually angled support surfaces (62, 63) is designed as a receiving cavity for a cutting tool (SW) which, during machining of at least one of the two mutually angled support surfaces (62, 63), can engage in the receiving cavity without cutting engagement with the same.

8. Trailer coupling according to one of the preceding claims, characterized in that at least one of the support surfaces (62, 63) is machined by a broaching tool, in particular a broaching needle.

9. Trailer coupling according to one of the preceding claims, characterized in that a plurality of support surfaces (62, 63), in particular mutually opposite and / or mutually angled support surfaces (62, 63), of the coupling arm receptacle (60) are machined by a single tool (SW), in particular a single reaming tool.

10. Trailer coupling according to one of the preceding claims, characterized in that a basic contour or raw contour (160) of the coupling arm receptacle (60) is produced by a forging tool (S1, S2) which, during forging of a blank (150) of the coupling arm support (50; 250; 350; 450), engages in a recess for producing the coupling arm receptacle (60) or in the coupling arm receptacle (60), in particular from opposite sides of the coupling arm receptacle (60).

11. Trailer coupling according to one of the preceding claims, characterized in that an arm portion (56) projects from the holding portion (53; 353) of the coupling arm support (50; 250; 350; 450), on which arm portion the receiving portion (59) is arranged, wherein the holding portion (53; 353), the arm portion (56) and the receiving portion (59) are in one piece.

12. Trailer coupling according to claim 11, characterized in that the arm section (56) is straight and / or without curvature.

13. Trailer coupling according to claim 11 or 12, characterized in that a longitudinal axis of the arm section (56) is at an angle to a pivot axis (S) forming in particular a single pivot axis, about which the coupling arm support (50; 250; 350; 450) is pivotally mounted between the use position (G) and a non-use position (N) provided for non-use of the trailer coupling, and / or at an angle to the plug-in axis (K) of the coupling arm receptacle (60).

14. Trailer coupling according to one of claims 11 to 13, characterized in that a longitudinal extension of the arm section (56) between the holding section (53; 353) and the receiving section (59) is shorter than the longitudinal extent of the receiving section (59) parallel to the plug-in axis (K).

15. Trailer coupling according to one of the preceding claims, characterized in that a front wall surface (74) of the receiving section (59), which extends around the insertion opening (66), is designed as a flat surface and / or as a surface produced by machining.

16. Trailer coupling according to one of the preceding claims, characterized in that the coupling arm receptacle (60) has a further opening (67) on a side opposite the insertion opening (66), wherein the further opening (67) preferably has a plug-in cross-section suitable for inserting the coupling arm (80).

17. Trailer coupling according to one of the preceding claims, characterized in that a plug-in cross-section of the plug-in receptacle (60A) of the coupling arm receptacle (60) is designed for the direct, positive-locking support of the coupling arm (80).

18. Trailer coupling according to one of the preceding claims, characterized in that a receiving sleeve (260) for receiving the coupling arm (80) is arranged in the coupling arm receptacle (60), wherein a particularly polygonal inner circumferential contour of the receiving sleeve (260) provides a plug-in cross-section for the positive circumferential holding of the coupling arm (80).

19. Trailer coupling according to claim 18, characterized in that the receiving sleeve (260) has a polygonal outer peripheral contour (275) which is positively received in a polygonal inner peripheral contour (61) of the coupling arm receptacle (60).

20. Trailer coupling according to claim 18 or 19, characterized in that the receiving sleeve (260) is arranged in front of the Clutch arm holder (60) and / or protrudes behind the clutch arm holder (60).

21. Trailer coupling according to one of the preceding claims, characterized in that at least one locking receptacle (68; 268), in particular a pair of opposing locking receptacles (68; 268), for receiving a locking element, in particular a locking bolt, for locking the coupling arm (80) is arranged on the receiving section (59).

22. Trailer coupling according to claim 21, characterized in that the at least one locking receptacle (68; 268) passes through the coupling arm receptacle (60) and / or a receiving sleeve (260) which is received in the coupling arm receptacle (60).

23. Trailer coupling according to one of the preceding claims, characterized in that at least one eyelet (75; 375) for a breakaway cable is arranged on the coupling arm support (50; 250; 350; 450), wherein the eyelet (75; 375) is advantageously integral with the coupling arm support (50; 250; 350; 450).

24. Trailer coupling according to one of the preceding claims, characterized in that on opposite sides of the receiving section (59) and / or the coupling arm receptacle (60) there is arranged in each case an eyelet (75; 375) for a breakaway cable, in particular one-piece with the coupling arm support (50; 250; 350; 450).

25. Trailer coupling according to one of the preceding claims, characterized in that the coupling arm support (50; 250; 350; 450) is adjustable with respect to the holding base (11) between a use position (G) provided for coupling the trailer (AH) or the rear load carrier (LT) and a non-use position (N) provided for non-use of the trailer coupling (10).

26. Trailer coupling according to claim 25, characterized in that the coupling arm support (50; 250; 350; 450) can be detachably fastened to the holding base (11), in particular the holding section (53; 353) has a plug-in projection which can be inserted into a plug-in receptacle of the holding base (11).

27. Trailer coupling according to claim 25, characterized in that the holding section (53; 353) forms a bearing section and the holding base (11) forms a bearing base, wherein the coupling arm support (50; 250; 350; 450) is pivotally mounted on the holding base (11) by means of the bearing section about a pivot axis (S) between the use position (G) and the non-use position (N).

28. Trailer coupling according to one of the preceding claims, characterized in that the plug-in axis (K) of the coupling arm receptacle (60) and a bearing axis of a bearing receptacle which is in pivotally mounted engagement with the holding base (11) are angular to one another.

29. Trailer coupling according to one of the preceding claims, characterized in that the bearing receptacle is designed as a bore produced by a drilling tool (BWZ) or milling tool.

30. Trailer coupling according to one of the preceding claims, characterized in that the coupling arm receptacle (60) is manufactured using two geometrically and / or functionally different tools.

31. Trailer coupling according to claim 30, characterized in that the coupling arm receptacle (60) is manufactured using a first tool (S1, S2, SW1) with a first, in particular rounded or round, outer circumferential contour (AUK1) and using a second tool (SW2) with a second outer circumferential contour (AUK2) different from the first outer circumferential contour (AUK1), in particular a polygonal and / or outer circumferential contour suitable for producing a plane or flat planar surface or the at least one support surface (62, 63) as a planar surface or flat surface.

32. Method for producing a trailer coupling for a motor vehicle (100), which is provided for coupling a trailer (AH) or a rear load carrier (LT), wherein the trailer coupling (10) has a vehicle mounting (95) which is fastenable or fastened to the motor vehicle (100), wherein the vehicle mounting (95) has a holding base (11) on which a coupling arm support (50; 250; 350; 450) is held by a holding section (53; 353) at least in a use position (G) provided for coupling the trailer (AH) or the rear load carrier (LT), wherein on the holding section (53; 353) of the coupling arm support (50; 250; 350;450) a receiving section (59) with a coupling arm receptacle (60) for receiving a coupling arm (80) forming in particular a component of the trailer coupling (10) is arranged at least in the use position (G), wherein the coupling arm receptacle (60) is designed as a plug-in receptacle (60A) with an insertion opening (66) through which the coupling arm (80) can be inserted into the coupling arm receptacle (60) along a plug-in axis (K) at least in the use position (G) and is ready for coupling the trailer (AH) or rear load carrier (LT), characterized by; - machining a raw support surface (162A, 162B, 163A, 163B) of the coupling arm holder (60) using a cutting tool (SW) to produce a support surface (62, 63) of the coupling arm holder (60) which is provided and designed to support the coupling arm (80).

33. Method according to claim 32, characterized by using a first tool (S1, S2, SW1) with a first, in particular rounded, outer circumferential contour (AUK1) for producing a raw contour (461) and a subsequent use of a second tool (SW2) with a second outer circumferential contour (AUK2) different from the first outer circumferential contour (AUK1), in particular for producing the at least one support surface (62, 63).

34. Method according to claim 32 or 33, characterized by producing a raw contour (161) of the coupling arm receptacle (60), in particular using a casting core or a forging tool (S1, S2), wherein the raw contour (161) has at least one raw support surface or a part thereof in the form of a Partial support surface (162A, 163A, 162B, 163B) for producing the at least one support surface (62, 63), wherein the raw support surface runs from the insertion opening (66) into the plug-in receptacle (60A) in the sense of a narrowing obliquely to the plug-in axis (K).

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