EP2045039A1 - Grinding or polishing disk with thread element - Google Patents

Abstract

The disk (1) has a carrier disk (2) provided with grinding lamellas (3) on a front side, and a hollow cylindrical-shaped passage opening (4) provided at middle of the carrier disk. A threaded insert (5) is inserted into the opening for retaining a drive shaft of a drive machine, where the length of a cylindrical part (51) of the threaded insert lying in the opening is shorter than the length (L2) of the opening. The length of the part is measured such that a cylindrical recess (6) is formed at a rear side of the disk, where the recess retains a disk-shaped section at the drive shaft.

Description

The invention relates to a grinding or polishing wheel, comprising a rotationally symmetrical carrier disk, with a hollow cylindrical passage opening for receiving a drive shaft of a drive machine, wherein the hollow cylinder axis coincides with the axis of rotation; and a threaded insert for a grinding or polishing disc, with a continuous internal thread whose axis of symmetry coincides with the axis of rotation, for receiving a drive shaft of a drive machine.

Such machine-operated grinding or polishing wheels are usually bolted to a drive shaft of an electrically operated machine. Since the grinding or polishing wheels are consumables and must be changed more frequently between different grits, a simple mounting option is required. Different mounting systems are offered and used for the different grinding or polishing wheels. In the most common variant, the grinding or polishing disc is attached to the drive shaft and then fixed by means of a clamping nut on this. In another embodiment, the disc itself comprises an internal thread in the passage opening. Thus, the grinding or polishing wheel can be screwed directly onto the drive shaft, which has a corresponding outer thread. The latter variant allows a particularly fast mounting and dismounting of the grinding or polishing wheel. The direction of rotation of the thread of the drive shaft is designed so that the grinding or polishing wheel is constantly tightened during the grinding process and thus can not relax.

In selecting the materials to be used for grinding or polishing discs, environmental and health compatibility play an important role in addition to the mechanical properties. Under these conditions, the use of various plastics offers at. In order to achieve the properties important for the grinding process, it has also proven a gain with natural fibers.

The production of abrasive or polishing wheels with an internal thread in the through-hole, in comparison to grinding or polishing wheels with only one through-hole, requires more extensive production activities, thereby resulting in higher production costs. In the other case, when using clamping nuts for attachment of grinding or polishing discs on the drive shaft, but a separate clamping nut is required. Since these are handled separately from the grinding or polishing disc, the grinding or polishing disc can not be fixed if they are lost. A grinding or polishing is then not possible.

The object of the invention is therefore to provide a grinding or polishing pad of the type mentioned above, which is suitable for direct mounting on a drive shaft of a drive machine in a simpler and improved manner.

This object is achieved by the features of claim 1 for a grinding or polishing pad and by the features of claim 5 for a threaded insert, wherein expedient developments of the invention by the features in the respective subclaims are shown.

According to the invention, a grinding or polishing disc according to the invention has a carrier disk, which is equipped on its front with abrasive blades and the center has a hollow cylindrical passage opening, wherein in the passage opening a threaded insert is arranged for receiving a drive shaft of a drive machine. The threaded insert in this case has a cylindrical part whose length is shorter than the length of the passage opening itself. In this case, the length of the cylindrical part is dimensioned so that at the back of the grinding or polishing disc an annular recess is formed, which for receiving a disc-shaped paragraph serves on the drive shaft.

The length of the recording of the disc-shaped shoulder of the drive shaft should be slightly larger than the height of the shoulder on the drive shaft itself, so that the lower free end of the cylindrical part during the grinding process can still be screwed when tightening in the direction of the drive shaft, so that the threaded insert can be further tightened with the grinding or polishing wheel. Thus, a safe operating state during polishing or grinding is generated. With a press fit can thus be carried out in a simple manner, the joining of the threaded insert in the carrier disk. The grinding or polishing wheel is placed on the spindle of the drive of the drive machine and turned on manually, where only slightly with your fingers along the peripheral edge of the carrier disk must tighten to get a secure grip of the grinding or polishing disc on the spindle. During the grinding or polishing process itself, the carrier disk is then tightened with the threaded insert firmly against the spindle of the drive machine.

In an expedient development, the grinding or polishing disc has a ring-cylindrical reinforcement projecting along the through-opening on the front side of the carrier disk in order to reinforce the through-opening along its outer opening edge in the direction of the axis of rotation.

This reinforcement serves on the one hand as a contact surface for the threaded insert and on the other to extend the passage opening as an additional support surface on the holding spindle of the drive.

In a particularly preferred embodiment, the grinding or polishing disc of the ring-cylindrical reinforcement on radially outgoing ribs, which are arranged on the front side of the carrier disc.

By this measure, the stability of the carrier disk is increased. But it is also possible to arrange ribs also on the back of the carrier disk or only there.

In a further embodiment, the grinding or polishing disc on the inner peripheral surface of the passage opening on a radially projecting into the inner region of the through hole injection-molded locking ring. The threaded insert has in its first region towards its free end to a widening, so that the free end of the threaded insert is positioned in the pressed-insertion in the carrier disc behind the locking ring snapped.

This locking ring is achieved due to production due to removal of the injection core, which remains when the injection core, which is symmetriebedingt arranged in the passage opening of the carrier disc, is punched out. This degree of demolition can be further refinished to serve as a locking edge for the threaded insert in this embodiment. In order to achieve latching, the threaded insert in the region which is inserted into the passage opening preferably has a conical widening. In other embodiments, instead of widening, this area of the threaded insert may also be created, for example by inserting protruding detents, detent projections created by entrances along the axis of rotation of the threaded insert in the first region or by radial detent rings disposed along the cylindrical periphery of the first region of the threaded insert ,

However, a joining of the threaded insert in the carrier disc need not be limited to a press fit. Other connections are possible, such as by gluing, shrinking, crimping the threaded insert to the carrier plate or vibration welding.

According to the invention, the threaded insert according to the invention for a rotationally symmetrical grinding or polishing wheel made of a plastic-natural fiber mixture. In a particularly preferred embodiment, the threaded insert is produced in particular from a plastic hemp fiber mixture.

The carrier disk is preferably produced by injection molding with the addition of hemp fibers. Thus, an environmentally friendly production of both the carrier disk and the threaded insert is possible because the proportion of the plastic is reduced by the proportion of hemp fiber. The admixture of natural fibers, especially hemp fibers, is thereby the increase in the toughness and strength of the parts beneficial.

In an expedient development, the threaded insert has a first region, which is cylindrical and has a second region, which is formed projecting radially over the first region, wherein the overhanging part of the threaded insert rests on the front side of the carrier wafer.

Thus, a stop is achieved in this construction, so that the annular end face of the second region can rest on the reinforcement of the carrier disk.

In an advantageous development, ribs are arranged in the first region of the threaded insert on the outer peripheral surface, which are oriented parallel to the axis of rotation and are formed in their rib height such that the threaded insert in the first region is fügbar by a press fit into the through hole.

By the ribs, with the height of which the interference fit can be defined, a simple measure is found to perform the joining between the threaded insert and carrier disc. In terms of production technology, this represents a favorable method. Depending on the height of the ribs, correspondingly pronounced interference fits can be obtained. The interference fit is to be designed so that a simple tightening the carrier disk with the threaded insert inserted therein on the spindle of the drive machine is possible without the threaded insert in the through hole when tightening the carrier disk rotates.

In an advantageous development, the ribs are designed such that they are formed decreasing in height in the direction of the free end of the first region.

Thus, a simple insertion of the first portion of the threaded insert is made possible in the passage opening of the carrier disk. By this wedge-like design of the ribs, a joining to be performed with increasing force is possible, which also allows a manual press fit with appropriate design of the maximum rib height.

In a further embodiment, the threaded insert on the inner end face of the second area radially projecting anchoring projections, which serve for anchoring to the support disk, in particular on the end face of the projection on the support disk.

When tightening the carrier disc with the threaded insert a Einkrallen the anchoring projections in the surface of the reinforcement of the support disc is possible, resulting in an increased attachment of both the threaded insert on the carrier disc, and thus an increased attachment of the carrier disc to the spindle of the drive machine. Thus, the reliability is further increased.

In an expedient development, the cylindrical part of the threaded insert also has, along its peripheral surface, circumferential anchoring projections which likewise serve for anchoring in the carrier plate. These may be formed in addition to, or as an alternative to, the anchoring projections in the second region.

With this embodiment, the reliability is further increased, whereby an independent release of the grinding or polishing wheel is virtually impossible.

In an expedient development, the end face of the second region of the threaded insert is formed crowned or rounded.

This ensures that the head of the threaded insert is not damaged or worn during grinding or polishing due to inclination of the grinding or polishing wheel. When working, in which the grinding or polishing wheel is held at an oblique angle to the surface to be machined, the machining is only possible or not disturbed by the crowned or rounded shape, since this area of the threaded insert does not stand in the way.

In an expedient development of the threaded insert in its end face of the second region at least two, preferably four point-symmetrical and equiangularly arranged blind holes, which serve to screw and loosen the grinding or polishing disc on the spindle. These blind holes are appropriate receptacles for hand tools, such. B. face spanner. Instead of a circular area cross section of the blind holes, other defined cross-sectional profiles can be arranged, such as square profiles, triangular profiles or simply grooves. Thus, the threaded insert be screwed or solved with the use of wells with defined cross-sectional profiles only with certain hand tools that are provided only by a particular provider. On the other hand, using standard face-hole wrenches allows easy and secure handling of the threaded insert for attachment and removal of the grinding or polishing disc mounted over the threaded insert.

In an expedient development, at least one welding survey is arranged in the region of the joint between the threaded insert and the carrier disk. Welding surveys have proven to be extremely useful in joining the joining parts threaded insert and carrier disk by means of vibration welding. They melt during vibration welding due to friction between the parts to be joined and ensure a favorable and secure welded connection. The use of welding surveys requires less pressure and thus less energy for joining, so that on the one hand costs are saved and on the other hand less stress on the parts to be joined. Sweat bumps are located either on the inner end face of the threaded insert or on the reinforcement of the carrier disc. Weld surveys are punctiform and / or rib-shaped, wherein they are arranged distributed on a support surface. Preferably, a plurality of weld projections are arranged rotationally symmetrically about the axis of rotation of the threaded insert. Preference is given to curved, rib-shaped weld projections, wherein the curvatures of the rib-shaped weld projections are preferably adapted to the curvature of the peripheral edge of the inner end face, so that the weld projections and the peripheral edge of the inner end face preferably have the same distance from each other. In this case, the weld elevations are preferably evenly spaced in the circumferential direction, so that there are free sections between the curved weld elevations without sweat elevation. Preferably, the weld projections have a tapered, for example, a triangular cross-sectional profile. This ensures that the bearing surface of the parts to be joined, for example, the bearing surface between the sweat elevation and the reinforcement of the carrier disk at the beginning of the vibration welding operation is small and then increases continuously, so that the component load due to pressure and friction is reduced. The height of the weld bumps is only a few tenths mm, in particular 0.3 mm.

Figur 1

eine Schnittdarstellung einer Schleifscheibe;

Figur 2

eine Schnittdarstellung eines Gewindeeinsatzes;

Figur 3a und 3b

jeweils eine perspektivische Darstellung in Draufsicht und Unteransicht des Gewindeeinsatzes mit Rippen und Verankerungsvorsprüngen;

Figur 4

eine Schnittdarstellung einer Trägerscheibe mit Spritzkern;

Figur 5

eine Schnittdarstellung einer Trägerscheibe nach Entfernung des Spritzkerns;

Figur 6

eine Schnittdarstellung einer Trägerscheibe mit eingesetztem Gewindeeinsatz;

Figur 7

eine Draufsicht auf eine Schleif- oder Polierscheibe ohne Schleiflamellen mit eingesetztem Gewindeeinsatz;

Figur 8

eine Schnittdarstellung eines Gewindeeinsatzes mit Sacklochbohrungen;

Figur 9

eine Seitenansicht eines Gewindeeinsatzes mit Rippen und Sacklochbohrung;

Figur 10

eine Unteransicht des Gewindeseinsatzes mit Schweißerhebungen; und

Figur 11

eine Schnittdarstellung des Gewindeeinsatzes mit Schweißerhebungen entlang Linie A-A aus Figur 10.

In the following the invention will be further explained with reference to preferred embodiments shown in the drawing. They show schematically:

FIG. 1

a sectional view of a grinding wheel;

FIG. 2

a sectional view of a threaded insert;

Figure 3a and 3b

in each case a perspective view in plan view and bottom view of the threaded insert with ribs and anchoring projections;

FIG. 4

a sectional view of a carrier disk with injection core;

FIG. 5

a sectional view of a carrier disk after removal of the injection core;

FIG. 6

a sectional view of a carrier disk with inserted threaded insert;

FIG. 7

a top view of a grinding or polishing pad without grinding blades with inserted threaded insert;

FIG. 8

a sectional view of a threaded insert with blind holes;

FIG. 9

a side view of a threaded insert with ribs and blind hole;

FIG. 10

a bottom view of the threaded insert with weld bumps; and

FIG. 11

a sectional view of the threaded insert with weld projections along line AA FIG. 10 ,

FIG. 1 shows a sectional view of a grinding or polishing wheel 1. This comprises a carrier plate 2, on which the grinding blades 3 are arranged on the front side V of the grinding or polishing wheel 1. Furthermore, the grinding or polishing wheel 1 has a central, hollow-cylindrical through-opening 4, whose cylinder axis coincides with the axis of rotation of the grinding or polishing wheel 1. In the through hole 4 of the threaded insert 5 is arranged joined by a press fit. The passage opening 4 in this case has a length which is denoted by L2. When inserted threaded insert 5 in the passage opening 4 from the direction of the front side V, an annular recess 6 remains on the back R of the support plate 2 left, which provides space for receiving a disc-shaped shoulder of the drive shaft. The threaded insert 5 in this case has a cylindrical part 51.

FIG. 2 shows a sectional view of the threaded insert 5, which comprises two areas B1 and B2. The first area B1 has the cylindrical part 51. The second region B2 has the overhanging part 52, which projects over the cylindrical part 51. The length of the cylindrical Part 51 is labeled L1. Here, the length L1 is smaller than the length L2 of the through hole 4 (see FIG. 1 ). Thus, a tightening of the threaded insert 5 in the through hole 4 is possible, since the length L1 is dimensioned such that it does not extend to the disc-shaped shoulder of the drive shaft. Thus, the cylindrical member 51 can be used in the direction of the drive shaft when grinding or polishing by tightening. The second region B2 of the threaded insert 5 has an inner end annular surface 56. The end face of the cylindrical part 51 forms the free end 55. The end face of the overhanging part 52 forms the upper end 58 of the threaded insert 5. The threaded insert is at least partially formed from a plastic. In particular, a plastic hemp fiber mixture is used as the material.

FIGS. 3a and 3b show perspective views of a threaded insert 5 in plan view and bottom view, respectively. In this embodiment, the threaded insert 5 on its end face 58 blind holes 10, which serve to receive Stirnlochschlüsseln. On the peripheral surface 53 of the cylindrical portion 51 ribs 54 are arranged, which serve the interference fit of the cylindrical portion 51 in the through hole 4 of the support plate 2. Depending on the design of the height of the ribs 54, a correspondingly strong or weak interference fit is generated. The side circumferential surface 59 of the overhanging part 52 is formed in a further embodiment at an inclination angle with respect to the end face 58, said angle in the range of 1 ° to 20 °, more preferably in the range of 1 ° to 10 °, and in particular 2 ° is selected to the front side surface. In the bottom view of the right figure of the FIG. 3 It is shown how on the inner end face 56 of the overhanging part 52, the anchoring projections 57 are formed. These are used for an additional attachment of the threaded insert 5 to the carrier plate 2 during tightening, which is done when grinding or polishing. The anchoring projections 57 can be formed in the form of a sawtooth, triangular or the like in their cross section. The ribs 54 are oriented parallel to the axis of rotation of the threaded insert and equiangularly over the circumference of the first region, here the cylindrical part 51, arranged. The ribs 54 are formed as radial projections which have a height such that an interference fit of the region B1 or cylindrical part 51 into the through-opening 4 is possible.

FIG. 4 shows a sectional view of a carrier disk 2. Here, the production step is shown, in which the injection core 11 is still arranged in the region of the passage opening 4. The passage opening 4 is not formed continuously due to the existing injection core 11. The core 11 is simply broken or punched out by exerting an axial force from the region of the passage opening 4.

FIG. 5 shows the next step in the production of the carrier disc with internal locking ring 9. The view shows a sectional view of the carrier plate 2, in which the core 11 has already been removed. What remains is a demolition bar, which serves as a detent ring 9. This locking ring 9 can be further reworked to rework the Abbruchgrad or to further define the measure of the locking ring. The locking ring 9 is arranged in the inner circumferential surface of the through hole 4 and preferably oriented orthogonal to the axis of rotation.

FIG. 6 shows a sectional view of the support plate 2 with inserted threaded insert 5 and locking ring 9 in the passage opening 4. In the embodiment with locking ring 9, the threaded insert in the area B1 to the open end 55 is expediently formed widening. In this case, the expansion is dimensioned such that in the inserted state of the threaded insert 5 in the passage opening 4, the flared end of the area B1 below the locking ring 9 comes to rest, whereby a locking between the open end 55 and locking ring 9 is generated. With this embodiment, another possibility of press fitting is realized.

FIG. 7 shows a plan view of a grinding or polishing pad 1. In this case, the grinding blades 3 are not shown. You can see the front of the sanding or polishing disc. In the center of the carrier disk 2, the threaded insert 5 is arranged. In this case, the inner end ring surface rests on the reinforcement 7, which is not visible in this plan view. Radially extending from the reinforcement 7 to the outside, ribs 8 are formed, which produce an additional reinforcement of the support disk 2. Preferably, the ribs 8 are arranged equiangularly between the projection 7 and the region on which the grinding blades 3 are arranged.

FIG. 8 shows a sectional view of the threaded insert 5. In this embodiment, blind holes 10 are arranged on the end face 58 of the area B2. However, the cross-sectional area of the blind hole 10 can also be determined individually defined so as to force only special hand tools from a supplier. Of course, standardized hand tools such as face spanner or the like. Can be used.

FIG. 9 shows a side view of the threaded insert 5. Here, in the end face 58, an opening of a blind hole 10 can be seen. It can also be seen that the side peripheral surface 59 of the second region B2 is formed with a slight inclination toward the front side surface 58. Particularly preferably, the inclination of about 2 ° is selected. In the region B1, which is the cylindrical part 51, the ribs 54 are arranged. In this embodiment, the press fit is produced in the passage opening 4 of the support disk 2 by the ribs.

A very good anchoring of the threaded insert 5 in the support plate 2 is also achieved in that the threaded insert has ribs 54 ( Fig. 3a, 3b ), and that complementary recesses (not shown) in the through hole 4 of the support disk 2 are present, which receive the ribs 54.

FIG. 10 shows a bottom view of the threaded insert 5 with weld projections 60. In this embodiment, four curved, rib-shaped weld projections 60 are located on the inner end face 56, with their curvatures adapted to the curvature of the peripheral edge of the inner end face 56, so that the weld projections 60 and the peripheral edge of the inner end annular surface 56 in the circumferential direction have a constant distance from each other. The weld bumps 60 are uniformly separated from each other by free sections, so that the melt film in the joint area can be evenly distributed in the rubbing direction, ie in the circumferential direction.

FIG. 11 shows a cross section of the threaded insert 5 along the line AA FIG. 10 , In this embodiment, the weld bump 60 has a triangular cross-sectional profile with a height of 0.3 mm. By this taper is achieved that the bearing surface of the parts to be joined, for example, the bearing surface between the weld bead 60 and the reinforcement 7 of the support plate 2, at the beginning of the vibration welding operation is small and then increases continuously, so that the component load due to pressure and friction reduced and the weld is made evenly and safely.

Claims (14)

A rotationally symmetrical grinding or polishing disc (1), comprising a carrier disc (2) which is equipped on the front side (V) with grinding lamellae (3) and which has a hollow cylindrical passage opening (4) in the center, and with a threaded insert (5) in the passage opening (4) for receiving a drive shaft of a prime mover,
characterized,
in that the length (L1) of the cylindrical part (51) of the threaded insert (5) lying in the passage opening (4) is shorter than the length (L2) of the passage opening (4) and dimensioned such that on the rear side (R) the Grinding or polishing disc (1) an annular recess (6) is formed, which serves to receive a disc-shaped shoulder on the drive shaft. Grinding or polishing disc (1) according to claim 1,
characterized,
in that the through-opening (4) is provided by a projecting ring-cylindrical reinforcement (7) of the support disk around the passage opening (4) in the direction of the axis of rotation on its front side (V). Grinding or polishing wheel according to claim 2,
characterized,
in that radially outgoing ribs (8) are formed on the carrier disk by the annular cylindrical reinforcement (7). Grinding or polishing wheel according to claim 1, 2 or 3,
characterized,
that the inner peripheral surface (41) of the passage opening (4) has a radially into the inner region of the passage opening (4) projecting molded-on locking ring (9) and the first region (B1) of the threaded insert (5) towards the free end (55) towards widened in such a way is formed, that the free end (55) of the threaded insert (5) is positioned in the pressed-in addition in the carrier disc (2) behind the locking ring (9) locked. Grinding or polishing disc (1) according to one of the preceding claims 1 to 4,
characterized,
in that at least one, preferably a plurality of weld projections (60) are arranged in the region of the joint for the purpose of establishing a connection between the carrier disk (2) and the threaded insert (5) by means of vibration welding. Threaded insert (5) for a rotationally symmetrical grinding or polishing disc (1) according to claim 1,
characterized,
that the threaded insert (5) consists of a plastic-natural fiber mixture, in particular of a plastic hemp fiber mixture. Threaded insert (5) according to claim 6,
characterized,
in that it is cylindrical in a first region (B1), and in a second region (B2) it projects radially over the first region (B1), wherein the overhanging part (52) on the front side (V) of the carrier wafer (2) is applied. Threaded insert (5) according to claim 6 or 7,
characterized,
that in the first region (B1) of the threaded insert (5) on the outer peripheral surface (53) ribs (54) are arranged, which are oriented parallel to the axis of rotation and formed in their rib height such that the threaded insert (5) in the first region (B1 ) is fügbar by a press fit into the passage opening (4). Threaded insert (5) according to one of the preceding claims 6, 7 or 8,
characterized,
in that the height of the ribs (54) decreases in the direction of the free end (55) of the peripheral surface (53). Threaded insert (5) according to one of the preceding claims 6 to 9,
characterized,
in that the inner end ring surface (56) of the second region (B2) has radially projecting anchoring projections (57) for anchoring on the carrier disc (2). Threaded insert (5) according to one of the preceding claims 6 to 10,
characterized,
in that it has circumferentially extending anchoring projections for anchoring in the carrier disc (2) on the peripheral surface (53) of the cylindrical part (51). Threaded insert (5) according to one of the preceding claims 6 to 11,
characterized,
that the end face (58) of the second region (B2) of the threaded insert (5) is formed crowned or rounded. Threaded insert (5) according to one of the preceding claims 6 to 12,
characterized,
in that the end face (58) of the second region (B2) has at least two blind holes (9), grooves or indentations of defined cross-sectional profile, symmetrically and equiangularly to one another, for screwing the threaded insert (5) with a corresponding tool. Threaded insert (5) according to one of the preceding claims 6 to 13,
characterized,
in that at least one, preferably a plurality of weld projections (60) are arranged in the region of the joint for the purpose of establishing a connection between the carrier disk (2) and the threaded insert (5) by means of vibration welding.

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