JP2013507256A - Screw rolling device - Google Patents

Abstract

  The present invention is an apparatus for forming a screw on a workpiece having a cylindrical outer surface by thread rolling, comprising a profiling tool (7) with a pitch-free profile, the axis of the profiling tool being the workpiece In an apparatus that is oblique or parallel to the axis of the disk, the profiling tool (7) is a disk (9) that is circular and is rotatably supported about the axis (8), and is ring-shaped from the outer peripheral surface of the disk. Two coaxial (10) non-pitch profiles (10) project and form an annular gap corresponding to the shape and dimensions of the thread profile of the screw to be formed.

Description

  The present invention relates to a device having a profiling tool with a pitch-free profile and threading a workpiece having a cylindrical outer surface by thread rolling, in which case the axis of the profiling tool is In particular, it is inclined with respect to the axis of the workpiece.

  Generally, thread rolling is a non-cutting process in which a screw is formed by cold working, and a profile is rolled on the surface of a corresponding unprocessed product. According to DIN8580, thread rolling belongs to deformation, more precisely pressure deformation and rolling. Machining is based on the generation of compressive stress on a workpiece by one or more tools. This method is much faster and more cost effective in mass production than other methods for forming screws, particularly those that are formed by cutting.

That is, the advantages of thread rolling are as follows.
There are no intergranular breaks that occur when threads are cut.
Surface hardening is obtained by cold deformation.
A press-polished screw side can be formed.
Higher wear strength results.
Not easily affected by notches.
Since no chips are produced, the demand for materials is reduced.
It is easier than threading.

  In conventional thread rolling with a flat tool, a pair of jaws is provided with a screw counter profile having a screw pitch angle, in which one jaw is fixed and the other jaw is movable. Has been placed. Since the workpiece rolls under the action of the frictional force, a screw is generated on the entire peripheral surface. The roller jaws have angled inlets and outlets and straight calibration parts.

  Thread rolling with a circular tool can be performed in an in-feed method or a through-feed method. Short or long screws can be rolled to the head. In the in-feed method, the rollers are provided with corresponding thread profiles having the same pitch angle but opposite twist directions. The workpiece is held either centerless or between both centers. Apart from a light compensatory movement, the workpiece is stationary in the axial direction during the rolling process. Since the ratio of roller diameter to workpiece diameter and the number of activations must be precisely adjusted relative to each other, a pair of rollers can be used only for a given screw.

  In the through-feed method, the rollers have screw profiles with no pitch arranged side by side. The roller rotates about its horizontal longitudinal axis by the required pitch angle. Thereby, when rotating, the workpiece is fed axially by a pitch angle. The rollers can also be used for different workpiece diameters to a limited extent. However, in this method, the pitch accuracy is lower than that in the infeed method.

  The self-opening screw roller head generally has three rollers. They are guided axially in contact with the workpiece and are automatically attracted onto the workpiece by the oblique position of the rollers. When a predetermined screw length is obtained, the roller head can be automatically opened and pulled back.

  Known screw rolling devices are always fixed in position. This is because they have large outer dimensions and large weight. An electrical drive is always necessary. The situation in which the screw is mechanically formed by a roller is also unique to the prior art in the area of thread rolling. In the course of intentionally changing threads, necessarily a plurality of tools, preferably rollers, must be replaced and a mechanical drive must be provided.

  It is an object of the present invention to provide a portable and relatively manually operable device for rolling male threads with a simple structure and a few outer dimensions.

  The problem is that, according to the present invention, the profiling tool is a circular disk that is rotatably supported about its axis, and protrudes from the outer periphery of the disk and has two ring-shaped coaxials that define an annular groove. This is solved by having a non-pitch profile, the shape and dimensions of the annular groove corresponding to the thread profile of the screw to be formed.

  The present invention relates to an apparatus for rolling a screw. In thread rolling, a workpiece is sandwiched between a rolling tool and a clamping device, and is fixed at a predetermined position by screw feeding. After the locking is performed, the screw can be rolled onto the workpiece by manual rotational movement. In that case, the thread geometry of the workpiece is determined by the rolling tool. The rolling tool is preferably formed as a quick change system, whereby any external thread can be formed.

  This type of device has a small structure that can be operated by hand with a simple configuration. The device does not require electrical drive and the force can be generated by muscle strength. Rather than the workpiece being attached to a thread rolling device, the device can be easily moved to where the screw is to be formed.

  Furthermore, it is not known from the prior art that the workpiece is supported as a plain bearing. This is because, according to the expertise of the average person skilled in the art, the newly rolled screw can be damaged. Rather, those skilled in the art will consciously attempt to avoid this type of sliding bearing to avoid screw damage.

  In the solution according to the invention, the hardening of the workpiece by a rolling process is used. That is, a standardized screw can be formed on a workpiece by combining a processing method in the form of thread rolling with dimensional design and material selection of the feed adjustment device. Here, the cut screw is actually relatively severely damaged when it is “slide bearing fed” in the axial direction. That is, the geometry and the load on the workpiece subject to the material are minimized.

  Use with inaccessible workpieces (inside machines that are cumbersome to remove) is also possible with the device according to the invention.

  Reliable holding in simple formation is when the cylindrical workpiece is held in a partial cylindrical groove in the support block and the longitudinal axis of the groove is arranged obliquely with respect to the axis of the profiling tool To be given. In that case, the support block can be adjusted transversely and in particular perpendicularly to the axis of the profiling tool, in particular manually.

  A preferred alternative support block of the workpiece is when the inner wall of the partially cylindrical groove has a threaded portion, the threaded portion substantially corresponding in shape and pitch to the screw to be formed on the workpiece, can get.

  Furthermore, it is proposed that the cylindrical workpiece is supported by at least two rollers that are axially parallel to the workpiece on the side facing the profiling tool, and that the rollers are supported by a support block. The

  Simple and easy handling is provided by the fact that the support block can be operated by a threaded rod, in particular manually, to adjust the spacing between the profiling tool and the support block.

  Preferably, it is proposed that the workpiece can be inserted and withdrawn axially and / or radially into the gap between the profiling tool and the support block. Particularly preferably, the thread rolling device can be operated manually as a manual tool and is portable.

  Embodiments of the present invention are shown in perspective in the drawings and will be described in detail below.

FIG. 3 shows a first embodiment in which a workpiece is held against a profiling tool in a groove of a support block. FIG. 6 shows a second embodiment in which the workpiece is held against the profiling tool by two rollers. FIG. 4 shows an embodiment with a closed ring-shaped frame.

  The thread rolling device 1 has a U-shaped frame 2 with a base 3 from which two arms 4 and 5 extend. The first arm 4 is divided into two arm one-side portions 4a, 4b by a longitudinal groove 6, in which a profiling tool 7 is supported on a shaft 8, the end of the shaft. Passes through one side portion 4a, 4b of the two arms, whereby the arm 4 is held.

  The profiling tool has a circular disc 9, the outer circular, annular, coaxially spaced outer periphery 10 of the disc has the same diameter and the same cross section, They form a coaxial annular groove whose cross section corresponds in shape and size to the cross section of the screw profile of the screw to be formed. In that case, the dimensions and cross-section of the outer periphery 10 are selected so as to correspond to the dimensions and cross-section of the screws to be formed.

  The support block 20 provided for pressing a rod-shaped workpiece having a cylindrical outer side against the profiling tool has a partially cylindrical groove 12 in which the workpiece is inserted, in which case The concave groove surface can have a profile according to the screw to be formed. On the side opposite to the groove 12, the screw rod 13 supported by the support block 20 engages with a complementary hole in the outer arm 5 and is manually operated via a grip 14 provided on the outer end thereof. Can be rotated about its longitudinal axis, thereby moving the support block 20 closer to or away from the profiling tool.

  Instead of bearing the profiling tool 7 in the first arm, the profiling tool 7 can be bearing in the support block 20 and the first arm 4 can form a counter support with grooves 12. Furthermore, the support block 20 can support two guide wheels or two guide rollers 21, as shown in FIG. 2, which engage the thread of the workpiece. Alternatively, the surface of the roller 21 can be a smooth cylinder, especially when repairing screws.

  Furthermore, the frame 2 is not U-shaped but can be closed, i.e. the two arms 4 and 5 are connected by the upper part 2a, so that the frame 2 is ring-shaped and is shown in FIG. Thus, the support block 20 is located in the central opening.

  In all configurations, the disc 9 and the rotational axis 8 of the two outer peripheries 10 are arranged obliquely with respect to the axis of the groove 12 or with respect to the guide edge, so that only a ring-shaped groove is present in the workpiece. Instead, a continuous thread occurs. In this case, the angle of the oblique arrangement is about 0.4 ° to 10 °. In order to repair the damaged screw, the oblique position can be eliminated, i.e. the guide, in particular the groove 12, is parallel to the axis 8 of the profiling tool in the support block or guide part 20.

  The advantage of applying the tool according to the present invention without using a machine is that it can be done without being tied to a place, can be used flexibly, for example to save installation time. Thus, the tools are suitable for forming a small number and can be formed much cheaper than, for example, a roll head. This is because the tool consists of a few simple parts.

  This is made possible by the use of a separate profile roller, arranged opposite the support element, for shaping. Profile rollers in known tools have a profile with a pitch or a non-pitch profile in the form of a rib or ring that goes around a circle. In the present invention as well, a non-pitch profile is used to shape, but of course this profile has exactly two rounding ribs or rings between which they are molded. It is characterized by the formation of a ring-shaped gap approximately corresponding to the thread profile to be achieved. The profile can have more rings, but only two engage the workpiece when used.

  This shape of the profile roller (exactly two circular rings or ribs that engage a defined gap) minimizes the force that must be applied to allow the profile roller to enter the material. In addition, the profile roller is inclined with respect to the workpiece axis by approximately the thread pitch, so that complicated forcing guides, as in conventional tools, can be omitted, but the profile roller is nevertheless accurate. The profile is cut into the workpiece at the desired pitch.

  In order to be able to provide the necessary force for the profile roller to enter the workpiece, the workpiece is supported by a support element on the side opposite the profile roller. This can be formed, for example, as a solid body with a negative profile adapted to the screw. What is important in this support element is that it transmits the force to the workpiece as large an area as possible and not in the form of dots.

  The preferred form of the tool is similar to that of a pipe cutter, but the pipe cutter uses a straight cutting wheel instead of an angled profile roller that provides a profile with the invention described so far. In being different.

  The proposed form of the tool is characterized in that it is formed as a hand-held portable tool. In that case, the profiling tool and the support element can be applied tangentially to each other. In that case, at least one non-actuated position is adjustable, in which the workpiece can be introduced between the profiling tool and the support element. For the workpiece, being able to be introduced both axially and tangentially offers the greatest possible flexibility. Furthermore, with one tool, a screw can be formed not only at the end of the workpiece but also at an arbitrary position. What is important in that case is that the profiling tool and the support element are located in one force flow plane, so that no bending or tilting moment is generated by the locking device on the workpiece to be machined. In this case, the tool is formed such that the profiling tool is inclined with respect to the workpiece axis by an angle substantially corresponding to the screw pitch.

  Furthermore, possible feed adjustments not only attach the tool to the end of the workpiece, but also allow the screw to roll from the center of the workpiece towards the end of the workpiece. This prevents the tool from being inadvertently installed at an angle. In order to avoid tilting or mounting at an angle, it is possible to dispense with gripping the workpiece at the workpiece end, as is usual during threading. At the same time, the advantageous properties of a screw formed by this type of method are realized manually in a portable way, since the favorable properties of machining without chipping can be exploited with the device according to the invention.

  In that case, in a surprisingly simple manner, after adjusting the feed with a predetermined feed force, the external thread can be removed without causing chips by rotating the entire device about the tool longitudinal axis in the working position. The screw geometry that is formed and then to be formed by the profiling tool is uniquely predetermined with respect to profile depth and profile shape. Inclined or inaccurate formation of the profile is not possible in practice. “Too strong” feeding is also impossible. This is because the force begins to rise exponentially as soon as the space between the two ribs or rings providing the profile is completely filled by the deformed workpiece. In that case, the geometry of the workpiece only requires a substantially cylindrical outer surface and may be formed in the shape of a pipe, or may consist of a solid material. Furthermore, since the external thread can be completely formed to a predetermined point, it is possible to form a screw without runout. In this case, since no electrical energy supply is required, various possibilities of use are given.

  Of course, other forms of the tool are also conceivable, in which the tool can be introduced only in the axial direction, and of course this form therefore does not have to be made very rigid. This is because the force can be effectively absorbed by the tool body.

  Another possibility of using this tool is screw repair. The deformed male screw is formed again by the tool. Based on the oblique position of the profile roller, a relatively large damage is improved much better than with known tools. However, as already explained, the repair of the screw is carried out with a high quality, even when the profile roller is not inclined, ie its axis is parallel to the longitudinal axis of the workpiece.

  The profile of the profiling tool and the angle at which the profiling tool is tilted with respect to the workpiece axis depends on the type of screw to be formed, so the parts of the tool (roller and counter holder that give the shape) can be changed without effort It is effective to design so that the tool can be used to form various screw types. This is also meaningful by the fact that the counter holder and profile roller wear over time and must be renewed in that case.

Claims (8)

An apparatus (1) for forming a thread on a workpiece having a cylindrical outer surface by thread rolling, comprising a profiling tool (7) with a pitch-free profile, the axis of the profiling tool being the workpiece In devices that are oblique or parallel to the axis,
The profiling tool (7) is a disc (9) that is circular and is rotatably supported about the axis of rotation, and protrudes from the outer peripheral surface of the disc and has two coaxial and pitch-free profiles defining an annular groove (10) characterized in that the shape and dimensions of the two profiles (10) correspond to the profile of the screw to be formed.   The cylindrical workpiece is held in the partial cylindrical groove (12) of the support block (20) and the longitudinal axis of the groove is arranged obliquely with respect to the axis of the profiling tool (7). The apparatus of claim 1.   3. Device according to claim 2, characterized in that the support block (20) is adjustable transversely and in particular perpendicularly to the axis of the profiling tool (7), in particular manually.   4. The inner wall of the partial cylindrical groove (12) has a threaded portion, the threaded portion substantially corresponding in shape and pitch to a screw to be formed on the workpiece. The device described in 1.   The cylindrical workpiece is supported by at least two rollers (21) parallel to the workpiece on the side facing the profiling tool (7), and the rollers are mounted on the support block (20). The apparatus according to claim 1, wherein:   3. The support block (20) is particularly manually operable by means of a threaded rod (13) to adjust the distance between the profiling tool (7) and the support block (20). The apparatus according to any one of 5.   The workpiece can be inserted and removed axially and / or radially into the gap between the profiling tool (7) and the support block (20). The apparatus as described in any one of.   The apparatus according to claim 1, wherein the apparatus is manually operable as a manual tool and is portable.

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