Steering arrangement with screw guide for a vehicle, and method for producing a steering arrangement

Abstract

A steering arrangement comprising a steering spindle head (1), a steering wheel (3), a screw (5), and a guide element (7) with a continuous recess designed to guide at least a portion of a shaft of the screw (5), wherein the steering wheel (3) and the steering spindle head (1) can be brought into positive engagement with one another in a torque-transmitting manner, and wherein the steering spindle head (1) has a radially centered threaded bore (9) in order to permanently fix the steering wheel (3) to the steering spindle head (1) by means of the screw (5) when screwed into the threaded bore (9) by means of the axial force of the screw (5), while the steering spindle head (1) and the steering wheel (3) are in torque-transmitting engagement with one another, and wherein the guide element (7) is designed to be fixed to an end face of the steering spindle head (1),to create a radial guide by means of the recess when screwing the screw (5) into the threaded hole (9) of the steering spindle head (1).

Description

[0001] The invention relates to a steering arrangement comprising a steering spindle head, as well as a method for producing such a steering arrangement.

[0002] When assembling a vehicle such as a passenger car, a steering wheel is typically mounted on a steering spindle. In order to transfer torque from the steering wheel to the steering spindle, a torque-transmitting connection between the steering wheel and the steering spindle must be created with as little play as possible to achieve precise steering without steering play during vehicle operation.

[0003] Secondly, the steering wheel and the adjoining steering spindle must be connected axially to one another. If, for this purpose, an internal thread is created at one end of the steering spindle in order to insert a screw (a so-called steering wheel screw) that fixes the steering wheel in the axial direction to the steering spindle, there is a risk that this internal thread will develop a fold during insertion, particularly if the end of the steering spindle is round-wrought. Under unfavorable boundary conditions, for example if the steering wheel screw is inserted at an angle, the steering wheel screw can seize if it is inserted at an angle to the intended axial direction of movement. This risk is particularly present when such a steering wheel screw is inserted mechanically. Manual reworking is time-consuming and therefore costly.If mechanical screwing is avoided from the outset to prevent skewed screwing and seizing of the threads and manual screwing is used instead, this will significantly lengthen the production process.

[0004] In a so-called steer-by-wire system (abbreviated "StbW") without a mechanical fallback, in some situations (e.g., during installation), the steering wheel can turn virtually forcelessly if the system is not powered. This distinguishes the installation from a conventional steering system, in which the steering spindle is fixed in the vehicle.

[0005] Steering arrangements are known in the prior art in which a plastic element is used to connect between the steering spindle and a steering coupling in order to simplify the alignment of the steering spindle during the assembly process.

[0006] DE 10 2011 109 691 A1 relates to a steering arrangement which has a steering spindle with a steering spindle connection which is connected to a fork head of a steering coupling via an intermediate piece, wherein the steering spindle connection and the intermediate piece are designed as plug-in partners at mutually facing ends by means of at least one pair of tongue and groove guide elements which provide a torque-transmitting forced guide, wherein a groove and a tongue of the at least one pair of tongue and groove guide elements are oriented longitudinally axially on the steering spindle connection and the intermediate piece and that the steering arrangement comprises a clamping device by means of which the plug-in partners can be clamped against one another in a plug-in position.

[0007] From FR 2 729 113 A1 a device for fastening a steering wheel to a steering shaft is known, comprising a steering spindle head, a steering wheel, a screw and a guide element with a continuous recess, wherein the steering wheel and the steering spindle head can be brought into engagement with one another in a form-fitting manner in a torque-transmitting manner, and wherein the steering spindle head has a radially centered threaded bore in order to permanently fix the steering wheel to the steering spindle head by means of the screw when screwing into the threaded bore by means of the screw when screwing it into the threaded bore by means of the axial force of the screw, while the steering spindle head and the steering wheel are in engagement with one another in a torque-transmitting manner.

[0008] However, this does not eliminate the risk of the steering wheel screw being placed at an angle on the internal thread of the steering spindle, where the steering wheel screw serves to axially press the steering wheel against the steering spindle and thus fix it. The object of the invention is therefore to make the screwing of the steering wheel to the steering spindle more reliable.

[0009] The invention is based on the features of the independent claims. Advantageous developments and refinements are the subject of the dependent claims.

[0010] A first aspect of the invention relates to a steering arrangement comprising a steering spindle head, a steering wheel, a screw, and a guide element with a continuous recess designed to guide at least a portion of a shaft of the screw, wherein the steering wheel and the steering spindle head can be brought into positive engagement with one another in a torque-transmitting manner, and wherein the steering spindle head has a radially centered threaded bore in order to permanently fix the steering wheel to the steering spindle head by means of the screw when screwing into the threaded bore by means of the screw, while the steering spindle head and the steering wheel are in engagement with one another in a torque-transmitting manner, and wherein the guide element is designed to be fixed to an end face of the steering spindle head in order to produce a radial guide by means of the recess when screwing the screw into the threaded bore of the steering spindle head.

[0011] The steering spindle head is the end piece of a steering spindle facing the steering wheel, which transmits the rotational movement of the steering wheel to a steering gear. The steering spindle head and the steering wheel are therefore connected to each other during vehicle assembly to transmit torque. To achieve sufficient precision and reliability in transmitting the steering movement of the steering wheel to the wheels, a positive connection is chosen. This positive connection is created during assembly by sliding the steering wheel axially onto the steering spindle head.

[0012] The positive connection is preferably created by a splined shaft connection between the steering wheel and the steering spindle head. This splined shaft connection uses a gear-like profile on the outer surface of the steering spindle head, which fits into the corresponding concave counterpart located centrally in the steering wheel. The steering wheel therefore preferably has a corresponding internal toothing that matches the external toothing of the steering spindle head. A fine toothing, for example, a 1x66 toothing, is particularly preferred. A fine thread M16x1.5 is preferably used for the screw.

[0013] On the side of such an external toothing of the steering spindle head facing away from the steering wheel, an opening cone is preferably provided in order to achieve an axial stop for the steering wheel and to ensure that the connection is free of play.

[0014] During assembly of the steering assembly, the steering wheel is pushed onto the steering spindle head to form the positive torque-transmitting connection, and the steering wheel is permanently connected to the steering spindle head by screwing it in place. The rotation of the screw moves it axially, i.e., perpendicular to the plane of the steering wheel, toward the steering spindle head as soon as the thread on the screw shaft engages with a threaded hole in the steering spindle head. The steering wheel has a corresponding through-hole for the screw shaft to pass through, as well as a corresponding holding stop to apply a counterforce to the screw head, which develops as the screw is increasingly screwed into the threaded hole in the steering spindle head.During this phase of assembly, there is the danger mentioned at the beginning that the screw may be inserted crookedly and that the external thread of the screw may become jammed and interlocked with the internal thread of the threaded hole, particularly due to a possible production-related fold.

[0015] To prevent this risk, a guide element with a continuous recess is arranged on the front side of the steering spindle head. This recess allows at least part of the screw shaft to be guided during assembly, ensuring the screw shaft is guided with high precision in the axial direction as desired when the thread of the shaft in the threaded hole executes the desired screwing movement for axially clamping the steering wheel to the steering spindle head.

[0016] This advantage of radially guiding the screw and preventing any angular deviation of the axial extension direction of the screw shaft relative to a central axis of the threaded hole is particularly evident in so-called steer-by-wire systems, where, in the absence of electrical voltage, there is typically no mechanical feedback or counterforce to apply a corresponding countertorque when screwing the screw into the internal thread of the threaded hole. Without the guide element, there is a particular risk of seizure due to a misaligned screw.

[0017] If the assembly is carried out correctly, a central axis of the threaded hole, which coincides with a central axis of the steering spindle head, the axial movement of the screw shaft and a central axis of the guide element lie together on a common straight line, on which the axial feed direction of the shaft of the screw takes place when screwing into the threaded hole of the steering spindle head.

[0018] Another advantage of using the guide element on the steering spindle head is that it simplifies the process of finding the correct position of the screw shank tip during the machined production of the screw connection. For this purpose, a corresponding cone can be provided in the guide element's recess to further simplify the process, making it easier to guide the screw shank tip securely into the recess.

[0019] If the guide element is made of plastic, complex geometries can be advantageously created. While the recess in the guide element preferably has a substantially circular cross-section to optimally guide the substantially circular cross-section of the screw shaft radially, more complex geometric sections can be used, particularly to create a fixed connection between the steering spindle head and the guide element, such as the positioning elements listed below, which can be pushed into the groove of the steering spindle head. Further options, such as reversibly releasable locking mechanisms, can be provided.

[0020] Should the guide element be lost during installation, the recessed, molded block teeth on the steering spindle head ensure secure and precise installation (fail-operational), albeit at the expense of comfort. The double conical shape of the block teeth allows for reliable and snag-free positioning of the correct position.

[0021] According to an advantageous embodiment, the recess of the guide element is a through hole with a circular cross-section.

[0022] According to a further advantageous embodiment, the steering spindle head is designed as a splined shaft with external teeth, and the steering wheel has internal teeth, so that the steering wheel and the steering spindle head are designed to form a splined shaft connection.

[0023] The splined shaft connection is preferably made of steel, both for the internal gearing of the steering wheel and the external gearing of the steering spindle head, to ensure secure and durable torque transmission between the steering wheel and the steering spindle head. This splined shaft connection is characterized by a large number of wedge-shaped drivers. While such a splined shaft connection, when the external and internal gearing are engaged, transmits torque during a steering movement, it has the advantage of being axially movable and can therefore be installed by axially sliding them together.Advantageously, the guide element is arranged on a front side of the steering spindle head in such a way that the internal toothing of the steering wheel can be pushed over the guide element; for this purpose, the guide element has a maximum radius equal to the lateral surface of the steering spindle head.

[0024] According to a further advantageous embodiment, the guide element has an axially projecting positioning element, wherein a groove is arranged on a circumferential surface of the steering spindle head, and wherein the positioning element can be inserted axially into the groove.

[0025] Several positioning elements can be provided, which can be inserted into a respective groove in the steering spindle head, allowing specific positioning between the shaft and hub for different steering wheel types. The respective groove in the steering spindle head interrupts the external toothing if the steering spindle head is designed as a splined shaft.

[0026] According to a further advantageous embodiment, the groove has a locking element which is designed to fix a projection of the positioning element by locking into place.

[0027] According to a further advantageous embodiment, the positioning element protrudes radially from a lateral surface of the steering spindle head after insertion into the groove, wherein the steering wheel has a stop which is arranged on the steering wheel in such a way that, even before the positive torque-transmitting connection between the steering wheel and the steering spindle head is established, the stop strikes the positioning element when the steering wheel is rotated relative to the steering spindle head, wherein, when the stop and the positioning element lie against one another, elements of the steering wheel and the steering spindle head which can be brought into positive engagement can be pushed axially onto one another to form the positive torque-transmitting connection.

[0028] The elements of the steering wheel and the steering spindle head that can be brought into positive engagement can be the external toothing of the steering spindle head and the internal toothing of the steering wheel, as described above. According to this embodiment, the guide element not only offers the function and advantage of avoiding oblique angles when inserting the screw and initially screwing it into the thread of the threaded hole, but also allows for a convenient joining of the steering wheel to the steering spindle head, especially when a splined connection is provided between the steering spindle head and the steering wheel.

[0029] It is intended that during assembly of the entire steering assembly, the steering wheel is initially pushed firmly over the guide element in the direction of the steering spindle head, but without a torque-transmitting connection being established between the two. The steering wheel can therefore still be rotated independently of the steering spindle head. In particular, a positioning element of the guide element is already inserted into a concave opening in the steering wheel, in which a stop is located. If the steering wheel is rotated until the stop and the positioning element are radially consistently aligned, the elements can be conveniently joined together to create the positive connection between the steering wheel and the steering spindle head, such as the splined shaft connection mentioned above, since a clear and intended rotational alignment of the steering wheel relative to the steering spindle head is achieved.In the example of the splined shaft connection, this is the axial sliding of the internal teeth of the steering wheel onto the external teeth of the steering spindle head.

[0030] Various designs can be used for the stop: On the one hand, the stop can cause the positioning element to press against the steering wheel when the steering wheel is turned at a sufficient angle. The stop can also be designed so that the positioning element itself engages in a recess in a concave recess of the steering wheel, thus providing a temporary radial fixation between the steering wheel and the steering spindle head.

[0031] According to a further advantageous embodiment, the guide element protrudes beyond the front side of the steering spindle head by a guide length of at least five millimeters.

[0032] The length by which the guide element extends beyond the steering spindle head is called the guide length and determines the alignment of the screw shaft when the screw is inserted relative to the desired axial feed direction of the screw. Naturally, it is advantageous to choose this guide length as short as possible to achieve a compact design. However, a certain minimum guide length is desirable to ensure secure alignment of the screw shaft against misalignment and to avoid damage to the outer surface of the screw and the internal thread of the threaded hole.

[0033] According to a further advantageous embodiment, the guide element is made of plastic and the steering spindle head is made of a metal alloy.

[0034] A further aspect of the invention relates to a method for producing a steering arrangement, wherein a guide element is arranged on an end face of a steering spindle head, a steering wheel is guided axially over the guide element and is brought into positive engagement with the steering spindle head in a torque-transmitting manner, and wherein a screw for fixing the steering wheel to the steering spindle head is guided with a shank of the screw through the steering wheel and then through a recess in the guide element and is then screwed into a threaded bore in the steering spindle head, so that by means of the recess a radial guide is produced when screwing the screw into the threaded bore in the steering spindle head.

[0035] According to a further advantageous embodiment, a positioning element of the guide element is introduced into a groove on a shell side of the steering spindle head in order to enable an axially forward rotational alignment between hub and shaft, and wherein the steering wheel is initially only pushed over the guide element so far that the steering wheel and the steering spindle head do not yet form a positive torque-transmitting connection, but when the steering wheel is turned, a stop already hits the positioning element, and wherein after the stop and the positioning element meet, the steering wheel is guided further axially over the guide element until the steering wheel and the steering spindle head form a positive torque-transmitting connection.

[0036] Advantages and preferred developments of the proposed method result from an analogous and analogous transfer of the statements made above in connection with the proposed steering arrangement.

[0037] Further advantages, features, and details will become apparent from the following description, which – where appropriate with reference to the drawings – describes at least one embodiment in detail. Identical, similar, and / or functionally equivalent parts are provided with the same reference numerals.

[0038] They show: Fig. 1: A steering arrangement according to an embodiment of the invention. Fig. 2: Remove the steering spindle head and the guide element from the Fig. 1 in detail. Fig. 3: The assembled steering arrangement of the Fig. 1. Fig. 4: A front side of the steering spindle head according to an embodiment of the invention.

[0039] The representations in the figures are schematic and not to scale.

[0040] Fig. 1 shows a steering assembly during assembly. First, a plastic guide element 7 is arranged on the front side of a steering spindle head 1. The arrangement is carried out with the help of three positioning elements 15, which protrude axially away from the guide element 7 in order to be inserted into a respective first groove 17 of the steering spindle head 1. The steering spindle head 1 also has an external toothing 11, which can be brought into engagement with an internal toothing 13 of the steering wheel 3 in order to create a torque-transmitting, positive-locking connection between the steering wheel 3 and the steering spindle head 1 after assembly is completed. After the guide element 7 has been applied to the front side of the steering spindle head 1, the guide element 7 having at most the outer diameter, as does the steering spindle head 1 in the area of ​​the external toothing 11 (cf. Fig. 2), the steering wheel 3 can be guided over the guide element 7 along the assembly direction outlined with a dash-dot line and applied to the external toothing 11. The steering wheel 3 is axially fixed to the steering spindle head 1 by means of a screw 5. This is first guided with its shaft through the hollow space within the internal toothing 13 of the steering wheel 3, then through a recess of the guide element 7 into a threaded bore 9 (see Fig. 4). The recess of the guide element 7 ensures that the shaft of the screw 5 is guided as precisely as possible in the axial assembly direction shown to the internal thread of the threaded bore 9, thus achieving a secure and reliable connection. Furthermore, a respective second groove 21 is provided in the steering wheel 3, into which a respective outer surface of the respective positioning element 15 is pushed in order to be able to conveniently align the steering wheel 3 radially correctly shortly before it is pushed onto the external toothing 11 of the steering spindle head 1 up to the maximum thrust formed by an expanding cone on the steering spindle head 1.

[0041] Fig. Figure 2 shows the steering spindle head 1 with the first groove 17 and a block tooth 19 in the first groove 17 in more detail. The time shown is during assembly, when the guide element 7 is brought to the front side of the steering spindle head 1, even before a respective positioning element 15 is inserted into a respective first groove 17. In the example shown here, the block tooth 19 serves as a fail-operational element, ensuring safe assembly in the event that the guide element 7 is lost.

[0042] Fig. Figure 3 shows the assembly result in a schematic section. The left half of the image shows the steering spindle head 1 with its widening cone, the steering wheel 3 is only schematically drawn, and the right half shows the head of screw 5. The external toothing 11 and the internal toothing 13 are already engaged. The screw 5 axially holds the steering wheel 3 to the steering spindle head 1.

[0043] Fig. 4 shows in perspective the steering spindle head 1 with its front side, whereby the threaded hole 9 is indicated, into which the thread on the shaft of the screw 5 can be screwed.

Claims

[1] Steering arrangement comprising a steering spindle head (1), a steering wheel (3), a screw (5), and a guide element (7) with a continuous recess designed to guide at least a portion of a shaft of the screw (5), wherein the steering wheel (3) and the steering spindle head (1) can be brought into positive engagement with one another in a torque-transmitting manner, and wherein the steering spindle head (1) has a radially centered threaded bore (9) in order to permanently fix the steering wheel (3) to the steering spindle head (1) by means of the screw (5) when screwed into the threaded bore (9) by means of the axial force of the screw (5), while the steering spindle head (1) and the steering wheel (3) are in engagement with one another in a torque-transmitting manner, and wherein the guide element (7) is designed to be fixed to an end face of the steering spindle head (1),to create a radial guide by means of the recess when screwing the screw (5) into the threaded hole (9) of the steering spindle head (1). [2] Steering arrangement according to claim 1, wherein the recess of the guide element (7) is a through hole with a circular cross-section. [3] Steering arrangement according to one of the preceding claims, wherein the steering spindle head (1) is designed as a toothed shaft with an external toothing (11), and the steering wheel (3) has an internal toothing (13), so that the steering wheel (3) and the steering spindle head (1) are designed to form a splined shaft connection. [4] Steering arrangement according to one of the preceding claims, wherein the guide element (7) has an axially projecting positioning element (15), wherein a first groove (17) is arranged on a circumferential surface of the steering spindle head (1), and wherein the positioning element (15) can be inserted axially into the first groove (17). [5] Steering arrangement according to claim 4, wherein the positioning element (15) protrudes radially from a circumferential surface of the steering spindle head (1) after insertion into the first groove (17), and wherein the steering wheel (3) has a second groove (21) which is arranged on the steering wheel (3) in such a way that, even before the positive torque-transmitting connection between the steering wheel (3) and the steering spindle head (1) is established when the steering wheel (3) is rotated relative to the steering spindle head (1), the second groove (21) strikes the positioning element (15), wherein, when the second groove (21) and the positioning element (15) lie against one another, elements of the steering wheel (3) and the steering spindle head (1) which can be brought into positive engagement can be pushed axially onto one another to form the positive connection. [6] Steering arrangement according to one of the preceding claims, wherein the guide element (7) projects beyond the end face of the steering spindle head (1) by a guide length of at least five millimeters. [7] Steering arrangement according to one of the preceding claims, wherein the guide element (7) is made of plastic and the steering spindle head (1) is made of a metal alloy. [8] Method for producing a steering arrangement, wherein a guide element (7) is arranged on an end face of a steering spindle head (1), a steering wheel (3) is guided axially over the guide element (7) and is brought into positive engagement with the steering spindle head (1) in a torque-transmitting manner, and wherein a screw (5) for fixing the steering wheel (3) to the steering spindle head (1) is guided with a shank of the screw (5) through the steering wheel (3) and then through a recess in the guide element (7) and is then screwed into a threaded bore (9) in the steering spindle head (1), so that by means of the recess a radial guide is produced when the screw (5) is screwed into the threaded bore (9) in the steering spindle head (1). [9] Method according to claim 8, wherein a positioning element (15) of the guide element (7) is introduced into a first groove (17) on a shell side of the steering spindle head (1) in order to secure the guide element (7) on the positioning element (15) against radial rotation on the steering spindle head (1), and wherein the steering wheel (3) is initially pushed over the guide element (7) only so far that the steering wheel (3) and the steering spindle head (1) do not yet form a positive torque-transmitting connection, but when the steering wheel (3) is rotated, a second groove (21) already meets the positioning element (15), and wherein after the second groove (21) and the positioning element (15) meet, the steering wheel (3) is guided further axially over the guide element (7) until the steering wheel (3) and the steering spindle head (1) form a positive torque-transmitting connection.

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