Method for producing a fixing device, and fixing device

Abstract

The invention relates to a method for producing a fixing device and to a fixing device, in particular in the form of a lock nut, such as a threaded nut or adjusting nut, comprising at least the following method steps: - completing a first thread (12) and extending a machining tool (13) into an intermediate space (18) in the direction of a further annular recess (6), - resetting the machining tool (13) within the intermediate space (18) in the direction of the first thread (12) by a predefinable distance (-ΔP), and - retracting the machining tool (13) again into the main body (16) in order to produce a second thread in the adjacent further annular recess (6), which has a pitch offset (P) to the first thread (12) as a result of the resetting of the machining tool (13).

Description

[0001]Spieth-Maschinenelemente GmbH & Co. KG Alleenstraße 41, 73730 Esslingen, Germany Method for manufacturing a locking device together with a locking assembly The invention relates to a method for manufacturing a locking assembly, in particular in the form of a locking nut, such as a threaded or adjusting nut. DE 102004003183 A1 discloses a threaded ring whose one-piece body, provided with an internal thread, has two body parts, the first of which forms an adjusting ring with a flat surface at its end lying in a radial plane, and the second of which forms a locking ring, which is connected to the first body part via an elastically compliant wall part of the body, forming a gap between the two body parts, and has an actuating device by means of which the geometry of the gap can be adjusted due to the elastic compliance of the wall part. Thereby,The fact that the bearing surfaces for the screw heads are designed with a defined inclination, so that the screw heads come into contact with the bearing surface on one side, avoids an otherwise demonstrable inclination of the nut bearing surface, thus advantageously increasing the proportion of the load-bearing thread to the total thread. US 2,376,927 discloses a lock nut with a base body comprising a load-bearing part and a locking part, which are integrally connected to one another via an elastically compliant collar with an undercut section.which separates the two aforementioned parts by forming an annular gap. For this purpose, with the base body stationary and thus fixed in place, a continuous thread with the same thread profile is cut into both the load part and the locking part using a machining tool in the form of a rotating milling cutter or a thread cutting device. This thread is interrupted by the gap. By moving the locking part towards the load part, against the restoring force of the forming collar, which is plastically deformed in the process,The gap between the threads decreases, and when a threaded counterpart is screwed into the lock nut along its external thread, the resulting thread misalignment causes the threaded counterpart to clamp and thus become fixed within the lock nut. A comparable design is described in DE 102021112290 A1, relating to a lock nut with a shaped collar arranged on an end face of a base or nut body and integrally connected to the nut body. The collar has an inner end face extending concentrically to an internal threaded bore of the nut body, which is axially spaced from the internal threaded bore and has a locking internal thread that is offset from an internal thread of the internal threaded bore.wherein an undercut section is formed axially adjacent to the end face on a radial outer surface of the shaped collar. Individual sections of this shaped collar with reduced wall thickness allow for adjustment or modification of the spring action of the shaped collar and thus also influence the generation of a locking or clamping torque on a threaded counterpart; usually as part of a bolt or spindle section. The two threads are offset from each other, in particular twisted or rotated relative to each other by an angle, such that when the threaded counterpart is screwed into the lock nut, an elastic deformation of the shaped collar is induced, so that a clamping force between the base or nut body and the shaped collar leads to a locking or self-locking of the threaded counterpart within the lock nut. Based on this prior art, the invention is based on the objective ofThe aim is to further improve known locking devices while retaining their advantages by achieving a particularly flat design in the axial screwing direction of the lock nut, thus enabling reliable use of the locking device even in confined installation conditions. A method for manufacturing a locking device with the features of claim 1 in its entirety, as well as a locking device according to claim 2, solves this problem. The method according to the invention includes at least the following process steps: - Providing a blank as a base body with two annular recesses of the same diameter arranged concentrically to its longitudinal axis and an intermediate space with a larger diameter.- Securing the blank to a clamping device and setting the blank into a rotary motion by means of the clamping device, - Inserting a machining tool into the gap to produce a first thread in the adjacent annular recess, - Completing the first thread and extending the machining tool into the gap towards the next annular recess, - Retracting the machining tool within the gap towards the first thread by a predetermined distance, and - Re-inserting the machining tool into the blank to produce a second thread in the subsequent annular recess, which, due to the retraction of the machining tool, has a pitch offset compared to the first thread. The clamping device is preferably manufactured on a CNC turning center.wherein a clamping device, as part of this turning center, can be set into rotation for a predetermined number of revolutions for the workpiece to be machined, similar to a lathe. The aforementioned pitch offset is created by retracting a milling cutter in the Z-direction by a predetermined distance, for example 0.3 mm, after the first thread has been cut in the load part, and then, starting from this new position and from the space between the two threads,The creation of the second thread in the locking element is carried out using this milling cutter. Therefore, in the software for the turning center, apart from specifying the respective Z-position for the machining tool (the milling cutter), no further information is required for manufacturing the thread offset itself. Thus, only an axial offset occurs between the two threads, and no intentional angular offset. Using this manufacturing method, a lock nut can be designed as a flat component whose axial length in the undeformed state is one-quarter to one-sixth, preferably one-fifth, of its original length.of the circumference of the blank or base body. Furthermore, the inventive method can be carried out reliably and cost-effectively. A certain spring stiffness of the locking element is necessary for the desired clamping or locking effect; however, from a material engineering perspective, the plastic deformation of the membrane must not be too high, so that, viewed axially, its geometrically small size contributes to the desired small overall size of the locking device. A locking device according to independent claim 2, in particular manufactured according to the above method, comprising at least two threads having the same thread profile, which are offset from each other and are continuously embedded in a base body, and which accommodate a space between them that is at least partially bounded at its edges by a membrane,This differs from the aforementioned known solutions in that the thread profile of one thread is continued in a fictitious extension in the direction of the other thread, and that, starting from this fictitious extension in the axial direction, a pitch offset is introduced before the other thread with the same thread profile is finished. In this way, the locking device can be manufactured in a cost-effective and production-reliable manner, considering its basic structure. In particular, the locking device, usually in the form of a clamping nut, such as a threaded or adjusting nut, is created in situ, without the need, as shown in the prior art, to first adjust the locking element onto the load part by plastically deforming a forming collar in order to obtain the required clamping preload. Only when the finished locking device or the locking nut is fixed onto a threaded counterpart,When the locking nut is typically in the form of a bolt or spindle section, the pitch mismatch is overcome, resulting in clamping, at least between a portion of the adjacent opposing thread flanks of the locking nut and the threaded counterpart. This generates high clamping forces despite the compact design of the locking nut. In a preferred embodiment of the locking device according to the invention, the base body is ring-shaped with a load-bearing section that has a thread with a greater number of pitches than the other thread, which is engaged in a locking section of the base body. In this way, the load-bearing section essentially carries the primary load, and the locking section carries at least that portion of the load required to clamp a threaded counterpart. Preferably, it is provided that...that the gap is designed as a recess, with the two threads, viewed radially, opening laterally into the base body with its annular rim overlapping them. The annular rim is preferably arranged between two annular boundary walls of the gap, each opening in the direction of an adjacent thread and thus forming a boundary for the respective entering and exiting thread profiles, so that a smooth transition is created. In a further preferred embodiment of the fixing device according to the invention, it is provided that the boundary wall adjacent to the thread with the fewer number of pitches has a wall section whose wall thickness is reduced in such a way that the spring-elastic diaphragm is formed. It is further preferred that the spring-elastic diaphragm is designed as a flat diaphragm.The diaphragm consists of a ring body with parallel annular surfaces, bounded on the inner circumference by the locking element, and transitioning on the outer circumference into the base body, which connects the load part to the locking element. In contrast to collar-shaped deformation elements with undercut sections, the diaphragm, as a flat component, is exceptionally flat, allowing the overall size of the locking nut to be kept small. Preferably, when a threaded counterpart or a spindle is screwed into the two internal threads of the base body along the respective external thread, the flat diaphragm experiences a deflection due to the pitch offset. This deflection results in a restoring force on the locking element and thus clamps the threaded counterpart or spindle in the base body.so that a functionally reliable locking mechanism is achieved. For rotary operation of the locking device on third-party components, such as a threaded counterpart or a spindle, it is advantageous that both the load part and the locking part with their threads, as well as the space between them, are arranged concentrically to each other on the inner circumference, with at least one point of engagement on the outer circumference for the application of a locking tool, for example, in the form of a suitable assembly wrench. Since preferably both the load part and the locking part project beyond the base body with a definable axial overhang, which has groove-like recesses on the outer circumference as points of engagement for the locking tool, the respective point of engagement for the locking tool is positioned in the direction of the longitudinal axis of the locking device, which in this respect also forms the center of rotation for the locking device.so that any potential imbalance during operation is effectively countered. The inventive locking device and the inventive method for manufacturing it are explained in more detail below with reference to an embodiment shown in the drawing. Figures 1 to 4 show, in principle and not to scale, the essential manufacturing steps for obtaining a locking device in chronological sequence; Figures 5 to 7 show the locking device in various sectional views and in one elevation, manufactured using a method with the individual manufacturing steps according to Figure 1. Figures 1 to 4 illustrate in principle the method for manufacturing a locking device, in particular in the form of a locking nut, such as a threaded or adjusting nut 10.where, viewed from the perspective of the viewer, only the upper half of the image is shown. Figure 1 shows the preparation of a blank in the form of a base body 16 with two annular recesses 4, 6 of the same diameter arranged concentrically to its longitudinal axis 2, and an intermediate space 18 in the form of an internal groove in the base body 16 with a larger diameter. While a first thread 12 is already partially cut into the annular recess 4, the second annular recess 6, in the form of a hollow cylinder, is still without further thread engagement. The second annular recess 6 widens conically towards its free end faces, and each conical widening forms a thread entry 8 or a thread exit 9 for a further second thread 14. The first annular recess 4, now partially provided with the first thread 12,The blank has such a thread entry 8 and thread exit 9. A clamping device 11, only partially shown, for example in the form of clamping jaws, of a conventional CNC turning center (not shown) serves to secure the blank in the form of the base body 16. The blank, or rather the base body 16, can be set into a rotary motion by means of the clamping device 11 using the turning unit of this turning center. The type of rotary motion corresponds to the number of thread pitches to be produced for a thread 12, 14. The pitch for one thread revolution should preferably be between 1 mm and 1.5 mm, for respective nominal diameters between 20 and 40 mm; always in 5 mm increments. The pitch, nominal diameter, and increments are preferably based on DIN 981 or DIN 1804. As further shown in Figure 1, a machining tool 13 in the form of a milling cutter moves, viewed in the direction of the arrow, along a Z-coordinate,into the blank or base body 16 and thereby creates the first thread 12 from the associated thread entry 8 to the thread exit 9. For the sake of simplicity, the machining tool 13 is only partially shown, in particular in the form of a partially shown chisel, with a cutting part 15 at the tip,which is also a component of the CNC turning center. When the machining tool 13, in the form of the milling cutter, moves in the direction of arrow Z, the first thread 12 is completed and the machining tool 13 exits the gap 18 with its milling cutter-like cutting part 15. As shown in Figure 2, the first thread 12 is then completed and the cutting part 15 of the milling cutter is located in the gap 18 without further engagement with the blank or the base body 16. This continues in the direction of arrow Z until a stopping point 17, shown as a dashed line in Figure 3, is reached, and at this point the cutting part 15 of the milling cutter has completely left the thread exit 9 of the first thread 12. Starting from Figure 3 and the holding point 17 shown there, the machining tool 13 is now reset within the space 18 in the direction of the first thread 12 to cover a predetermined distance - P of preferably 0.3 mm. This return movement, marked with , therefore occurs opposite to the other feed movement Z from left to right, as shown by the arrow in Figures 1, 2, and 4. The respective feed movement Z always occurs parallel to the longitudinal axis 2 of the base body 16. Continuing the manufacturing process after the return, the machining tool 13 is then inserted again into the base body 16 from a corresponding return position 19 (solid line in Figure 3) to produce the second thread 14.in the subsequent annular recess 6. As shown in Figure 4, the machining tool 13 again moves in the feed direction along arrow Z, and Figure 4 shows the position of the machining tool 13 shortly before exiting the second thread 14 via the associated right-hand thread runout 9. Due to the retraction of the machining tool 13 as shown in Figure 3, the second thread 14 now has a pitch offset P relative to the first thread 12. For the specified thread sizes M20x1, M25x1.5, M30x1.5, M35x1.5, and M40x1.5, a pitch offset P of 0.3 mm with a pitch tolerance of + / - 0.03 mm is used here. It is understood that other offset and tolerance values ​​may be used for other thread dimensions. The pitches of both threads are 12,The threads 14 with the same thread profile do not necessarily have to be integer multiples. For example, the first thread 12, designed as a load-bearing element 22, could have three pitches with each complete thread rotation, and the second thread 14 could have 1.5 or 2.5 pitches. Other appropriate pitch numbers, i.e., thread rotations per thread 12, 14, are possible. Figure 5 shows the adjusting nut 10 as a whole in longitudinal section. The adjusting nut 10 has two threads 12, 14, which have the same thread profile. These threads are continuously integrated into the base body 16 with a pitch offset P relative to each other, and they accommodate a space 18 between them, which is at least partially bounded at its edges by a membrane 20. As explained above, the thread profile of one thread 12 is continued in fictitious extension in the direction (Z-direction) of the other thread 14,where, starting from this fictitious extension viewed in the axial direction, the pitch offset P is introduced before the other thread 14 is produced with the same thread profile as the first thread 12. The base body 16, as can be seen particularly from the illustration in Figure 7, is ring-shaped and essentially consists of a load-bearing section 22, which has the thread 12 with a greater number of pitches than the other thread 14, which is received in a locking element 24 of the base body 16. The space 18 is designed as a recess in the base body 16 and, according to the longitudinal section, overlaps the two threads 12, 14 in the radial direction. Furthermore, the space 18 opens integrally into the outer circumference of the base body 16 with its annular rim 26. The ring edge 22 is arranged between two ring-shaped, flat boundary walls 28, 30 of the space 18,which each open in the direction of an adjacent thread 12, 14. The boundary wall 30 that adjoins the thread 14 with the fewer number of pitches has a wall section 32 whose wall thickness is reduced such that the spring-elastic diaphragm 20 is formed. This is designed as a flat diaphragm (see enlarged partial view according to Figure 6), which consists of a planar ring body 40 with two parallel annular surfaces 42, 44, wherein the diaphragm 20 is bounded on its inner circumference by the locking element 24, and which transitions on its outer circumference into the base body 16, which connects the load element 22 to the locking element 24 in this area. In this respect, all wall parts running transversely to the longitudinal axis 2 of the adjusting nut 10 are aligned parallel to the annular surfaces 42, 44 of the diaphragm 20, which has the smallest wall thickness of all wall parts of the adjusting nut 10.which corresponds to less than half the wall thickness of the locking element 24 with the second thread 14. If a threaded counterpart or spindle part (not shown) engages with the second thread 14 of the locking element 24 after passing through the first thread 12, the diaphragm 20 bulges slightly, while the locking element 24 with its thread 14 moves slightly to the right (as viewed from Figure 5). This creates a restoring force to the left, causing the threaded counterpart or spindle part with its external threads to wedge within the threads 12 and 14 and thus be secured within the adjusting nut 10. The corresponding counterpart to be screwed in is clamped solely due to the pitch offset P between the threads 12 and 14. As can be seen particularly in Figure 7,Four groove-like recesses 38 are provided on the outer circumference of the base body 16 as points of engagement 34, which serve for attaching a suitably appropriate locking tool in order to secure the adjusting nut 10 to the aforementioned threaded counterpart or spindle part. As can be further seen from Figure 7, the locking device shown there, particularly when viewed axially parallel to the longitudinal axis 2, is extremely narrow and has a total length of between 7 and 10.25 mm with an outer diameter of between 32 and 58 mm. This has no equivalent in the prior art.

Claims

Patent Claims 1. Method for manufacturing a locking device, in particular in the form of a locking nut, such as a threaded or adjusting nut (10), comprising at least the following process steps: - Providing a blank as a base body (16) with two annular recesses (4, 6) of the same diameter arranged concentrically to its longitudinal axis (2) and an intermediate space (18) with a larger diameter, - Fixing the blank to a clamping device (11) and setting the blank into a rotational movement by means of the clamping device (11), - Inserting a machining tool (13) in the direction of the intermediate space (18) to produce a first thread (12) in the adjacent annular recess (4), - Completing the first thread (12) and extending the machining tool (13) into the intermediate space (18) in the direction of the further annular recess (6),- Resetting the machining tool (13) within the intermediate space (18) in the direction of the first thread (12) by a predetermined distance (- P), and - Re-inserting the machining tool (13) into the blank to produce a second thread (14) in the subsequent further annular recess (6), which, due to the resetting of the machining tool (13), has a pitch offset (P) to the first thread (12).

2. Locking device, in particular manufactured according to a method according to claim 1, comprising at least two threads (12, 14), which have one and the same thread profile, which are continuously provided with an offset relative to each other in a base body (16), and which accommodate an intermediate space (18) between them, which is at least partially bounded at its edge by a membrane (20), characterized in that the thread profile of one thread (12) is continued in a fictitious extension in the direction of the other thread (14), and that, starting from this fictitious extension viewed in the axial direction, a pitch offset (P) is introduced before the other thread (14) is produced with the same thread profile.

3. Locking device according to claim 2, characterized in that the base body (16) is designed in an annular form with a load part (22) which has a thread (12) with a larger number of pitches than the other thread (14), which is received in a locking part (24) of the base body (16). 4.A fixing device according to one of the preceding claims, characterized in that the space (18) is designed as a groove and, viewed radially, extends laterally with its annular edge (26) into the base body (16), overlapping the two threads (12, 14) in the radial direction.

5. A fixing device according to one of the preceding claims, characterized in that the annular edge (22) is arranged between two annular boundary walls (28, 30) of the space (18), each of which opens in the direction of an adjacent thread (12, 14).

6. A fixing device according to one of the preceding claims, characterized in that the boundary wall (30) that... adjoining the thread (14) with the fewer number of pitches, a wall section (32) has a wall section (32) whose wall thickness is reduced such that the spring-elastic diaphragm (20) is formed.

7. Locking device according to one of the preceding claims, characterized in that the spring-elastic diaphragm (20) is designed as a flat diaphragm consisting of an annular body (40) with parallel annular surfaces (42, 44), which is bounded on its inner circumference by the locking element (24), and which transitions on its outer circumference into the base body (16) that connects the load section (22) to the locking element (24). 8.A locking device according to one of the preceding claims, characterized in that, when a threaded counterpart is screwed into the two threads (12, 14) of the base body (16) along its external thread, the diaphragm (20) undergoes a deflection movement due to the pitch offset (P), which leads to a restoring force on the locking element (24) and thus to a clamping of the threaded counterpart in the base body (16).

9. A locking device according to one of the preceding claims, characterized in that both the load part (22) and the locking element (24) with their threads (12, 14) as well as the intermediate space (18) are arranged concentrically to each other on the inner circumference and have at least one point of engagement (34) on the outer circumference for the engagement of a locking tool. 10.Locking device according to one of the preceding claims, characterized in that both the load part (22) and the locking part (24) have a predefinable axial projection. the base body (16) protrudes, which has groove-like recesses (38) on its outer circumference as a point of attack (34).

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