Patent Application
20190224814
The invention relates to a roughing grinding tool, in particular for the operation of handheld angle grinders, the roughing grinding tool having a supporting body, at least one abrasive circle, and a through-opening for fastening a tool drive.
In subtractive manufacturing processes, roughing denotes the removal of material in a large chip volume. In order to achieve a short machining time, roughing grinding tools are intended to allow a high removal capacity and at the same time to have a long service life.
EP 3 015 222 A1 discloses a grinding disk having a backing pad and a plurality of abrasive circles. The backing pad is stepped such that a plurality of annular portions are formed, to each of which an abrasive circle is fastened. The abrasive circles in this way form a multilayer abrasive circle stack. The abrasive circle stack forms a substantially frustoconically stepped recess. This makes it possible to position the grinding disk against a workpiece surface at different setting angles and allows largely complete working off of the abrasive circle stack until the backing pad reaches the workpiece surface and the grinding disk is worn out.
The invention is based on the object of creating a robust roughing grinding tool that is easy to produce and has a high removal capacity in conjunction with a long service life.
This object is achieved by a roughing grinding tool having a supporting body, at least one abrasive circle, and a through-opening for fastening a tool drive, wherein the supporting body comprises an abrasive grain for roughing grinding. According to the invention, the supporting body is configured for roughing grinding and comprises an abrasive grain. The supporting body thus serves both to support the at least one abrasive circle during rouging grinding and itself for roughing grinding, with the result that a high level of robustness and a long service life of the roughing grinding tool are achieved. The supporting body is configured in particular such that it complies with the safety requirement “single point side load” as per German standard DIN EN 12413 “Safety requirements for bonded abrasive products” (version of May 2011). The supporting body is also configured in a simple manner and is easy to produce. As a result of the choice of the abrasive grain, a high removal capacity for the material to be machined is achieved. The roughing grinding tool is configured for example as a grinding disk or as a grinding cup wheel.
The roughing grinding tool has one or more abrasive circles, which is or are arranged on the supporting body. The abrasive circle adjacent to the supporting body is fastened to the supporting body by adhesive bonding and/or riveting and/or screwing and/or stapling. If the roughing grinding tool has several abrasive circles, each further abrasive circle is fastened to the underlying abrasive circle by adhesive bonding and/or riveting and/or screwing and/or stapling. The adhesive bonding takes place by means of an adhesive layer, which preferably comprises a resin.
The at least one abrasive circle has in each case at least one abrasive layer with oriented abrasive grain and/or unoriented abrasive grain. The abrasive grain is in particular selected from diamond, cubic boron nitride (CBN), silicon carbide (SiC), natural corundum and/or synthetic corundum. The corundum is for example zircon corundum and/or aluminum oxide (Al2O3).
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A roughing grinding tool configured such that the supporting body forms an abrasive region that comprises the abrasive grain bonded by means of a bonding agent ensures a long service life. The abrasive grain is bonded by means of a bonding agent and forms an abrasive layer or an abrasive region. The bonding agent is in particular a synthetic resin, for example phenol resin. Preferably, the abrasive layer has, in the direction of an axis of the roughing grinding tool, a thickness that corresponds to a thickness of the supporting body. This means that the supporting body forms the abrasive layer over its entire thickness. The abrasive grain is in particular selected from diamond, cubic boron nitride (CBN), silicon carbide (SiC), natural corundum and/or synthetic corundum. The corundum is for example zircon corundum and/or aluminum oxide (Al2O3). The abrasive layer or the abrasive region is formed at least on a top side and/or on an underside of the supporting body. The abrasive grain of the supporting body is identical to and/or different than an abrasive grain of the at least one abrasive circle. The abrasive layers or the abrasive regions of the supporting body have an identical or different abrasive grain.
A roughing grinding tool configured such that the supporting body comprises at least one supporting-body reinforcement, which is arranged in particular next to a top side and/or underside of the supporting body, ensures a long service life. Preferably, the supporting body has two supporting-body reinforcements next to the outer sides of the supporting body, i.e. next to the top side and the underside of the supporting body. The at least one supporting-body reinforcement is joined to the supporting body by means of a bonding agent or a resin. The outer supporting-body reinforcements are impregnated for example with the bonding agent or resin. The outer supporting-body reinforcements are preferably in the form of a fabric, in particular a glass fabric or glass fiber fabric.
A roughing grinding tool configured such that at least one supporting-body reinforcement is embedded in the abrasive region ensures a long service life. Preferably, the supporting body has an inner supporting-body reinforcement, which is embedded in the abrasive layer or the abrasive region. The inner supporting-body reinforcement is interspersed with the bonded abrasive grain.
A roughing grinding tool configured such that the supporting body has a supporting-body outside diameter DT and the at least one abrasive circle has an abrasive circle outside diameter DS, wherein 0.1·DS≤DT≤1.2·DS, in particular 0.5·DS≤DT≤1.1·DS, and in particular 0.8·DS≤DT≤DS, ensures a high level of robustness and a long service life. Preferably, the supporting-body outside diameter corresponds to the abrasive circle outside diameter.
A roughing grinding tool configured such that the supporting body is formed in a disk-shaped manner and in particular has an offset is easy to produce and robust. A roughing grinding tool in the form of a roughing grinding disk is also universally usable. The supporting body and/or the at least one abrasive circle and/or at least one of the abrasive circles has/have preferably an offset.
A roughing grinding tool configured such that the at least one abrasive circle is arranged between a first supporting body and a second supporting body has an extremely long service life. The at least one abrasive circle, in particular an abrasive circle stack formed from several abrasive circles, is arranged between two supporting bodies which each comprise an abrasive grain for roughing grinding. The supporting bodies are constructed in an identical or different manner. The first supporting body is joined at a top side to the adjacently arranged first abrasive circle of an abrasive circle stack, while the second supporting body is joined at an underside to the adjacently arranged last abrasive circle of the abrasive circle stack.
A roughing grinding tool configured such that, for a number N of the at least one abrasive circle, 1≤N≤9, in particular 2≤N≤8, and in particular 3≤N≤7 ensures a high level of robustness and a long service life. The abrasive circles of the abrasive circle stack are arranged one above another in layers.
A roughing grinding tool configured such that a plurality of abrasive circles are arranged one on top of another, wherein a first abrasive circle is fastened to the supporting body and each further abrasive circle is fastened to an underlying abrasive circle, ensures easy production. The abrasive circles are arranged in a simple manner one above another and adjacent abrasive circles are joined together. Joining takes place in particular by adhesive bonding. Preferably, adjacent abrasive circles are joined together in an internal joining region and are not joined in a working region surrounding the joining region. The supporting body and the abrasive circle stack are thus easy to produce.
A roughing grinding tool configured such that a first abrasive circle is fastened to the supporting body and a second abrasive circle is fastened to the first abrasive circle ensures easy production. The first abrasive circle is fastened directly to the supporting body, while the second abrasive circle is fastened only to the first abrasive circle. The second abrasive circle is thus not connected directly to the supporting body but only indirectly. Joining takes place in particular by adhesive bonding. Preferably, the abrasive circles have an internal joining region, in which the first abrasive circle is joined to the supporting body and the second abrasive circle is joined to the first abrasive circle, and a working region which surrounds the joining region and in which the abrasive circles are not joined.
A roughing grinding tool configured such that the at least one abrasive circle forms a joining region and a working region surrounding the joining region, and the at least one abrasive circle is fastened in the joining region and is unfastened in the working region ensures a high removal capacity. The abrasive circles of an abrasive circle stack are preferably not joined in the working region and rest closely on one another in an unlaminated manner. Since the at least one abrasive circle is not joined in the working region, said abrasive circle, after it has worn out, is removed easily from the grinding process. The at least one abrasive circle is produced from abrasive material on a base. An abrasive grain is thus arranged on a backing layer or a base by means of a bonding agent. After the abrasive grain has worn out, targeted wearing of the backing layer or base in the working region is achieved in the grinding process, such that an underlying abrasive circle or the supporting body comes into engagement easily and quickly with the workpiece to be machined. As a result, a high removal capacity and a high level of aggressiveness of the roughing grinding tool are achieved. The working region of the at least one abrasive circle is formed in a substantially annular or disk-shaped manner.
A roughing grinding tool configured such that the at least one abrasive circle has an oriented abrasive grain ensures a high removal capacity. As a result of the oriented abrasive grain, a high level of aggressiveness and a high removal capacity are achieved. This allows in particular a flat use of the roughing grinding tool. The abrasive grain is preferably made of diamond, cubic boron nitride (CBN), silicon carbide (SiC), natural corundum and/or synthetic corundum. The corundum is for example zircon corundum and/or aluminum oxide (Al2O3).
A roughing grinding tool configured such that an abrasive circle reinforcement is fastened to at least part of the surface of the at least one abrasive circle ensures a high level or robustness. As a result of the abrasive circle reinforcement, high resistance with respect to tearing of the particular abrasive circle is achieved. The abrasive circle reinforcement is fastened to the at least one abrasive circle at least in a working region. Preferably, the abrasive circle reinforcement is fastened to the at least one abrasive circle over the entire surface, i.e. in a working region and a joining region. The abrasive circle reinforcement is fastened in particular to a rear side of the at least one abrasive circle. Preferably, the abrasive circle reinforcement is fastened to the rear side of the abrasive circle by means of a bonding agent, for example phenol resin. In particular, an abrasive circle reinforcement is fastened to each of the abrasive circles. The abrasive circle reinforcement is joined for example to the rear side or underside of the abrasive circle by means of a resin. Preferably, all the abrasive circles are joined to an associated abrasive circle reinforcement. If necessary, it is possible for only individual abrasive circles to be joined to an abrasive circle reinforcement. Preferably, the abrasive circle reinforcement is fastened to a rear side or underside of the at least one abrasive circle and/or embedded in an abrasive layer of the at least one abrasive circle. The bonding agent, in particular the resin, for fastening the abrasive circle reinforcement serves in particular also for fastening the abrasive circle to the supporting body or to the underlying abrasive circle.
A roughing grinding tool configured such that the at least one abrasive circle comprises a backing layer with abrasive grain arranged thereon, wherein the backing layer is configured in particular as paper, vulcanized fiber, nonwoven and/or backing textile, ensures easy production. The at least one abrasive circle is produced from abrasive material on a base. The base forms a backing layer for the abrasive grain arranged thereon. The backing layer is configured in particular as paper, vulcanized fiber, nonwoven and/or as a backing textile, for example as a woven fabric and/or laid fabric. The abrasive grain is arranged on the backing layer in an oriented and/or unoriented manner. The abrasive grain is bonded to the backing layer by means of a bonding agent. In addition, a top layer or top bonding may be arranged on the abrasive grain.
A roughing grinding tool configured such that the backing textile comprises polyester fibers, cotton fibers and/or glass fibers and is in particular a polyester/cotton blend ensures easy production and a long service life. The backing textile is in particular a backing fabric having at least one thread in a warp and a weft direction. Preferably, the backing textile is in the form of a polyester/cotton blended fabric.
A roughing grinding tool configured such that the at least one abrasive circle is stiffened with a filling resin ensures a long service life. The at least one abrasive circle is stiffened with a filling resin, such that a cyclical deviation of the at least one abrasive circle during the machining of a workpiece is reduced. As a result of a pronounced cyclical deviation, the abrasive grain is torn out of the base before the abrasive grain is worn away and has achieved its material removal potential. In addition, as a result of torn-out abrasive grains, the layer of abrasive material is weakened, since adjacent abrasive grains can no longer support one another. As a result of the stiffening, a pronounced cyclical deviation is prevented. The stiffening takes place by the abrasive circles formed from abrasive material on a base subsequently being provided with a filling resin with the filling resin then being cured. The filling resin is for example selected from the group consisting of thermosets, elastomers, synthetic resins and/or thermoplastics and combinations thereof. Preferably, the filling resin is a thermoset, for example phenol resin. The abrasive circles are easily provided or impregnated with the filling resin after they have been joined to the supporting body or an underlying abrasive circle. Preferably, the at least one abrasive circle is dipped in a bath of filling resin.
A roughing grinding tool configured such that the at least one supporting-body reinforcement and/or the abrasive circle reinforcement comprises glass fibers and/or jute fibers ensures a high level or robustness and a long service life. Preferably, the at least one supporting-body reinforcement and/or the respective abrasive circle reinforcement is a fabric, in particular a glass fiber fabric.
A roughing grinding tool configured such that the at least one abrasive circle forms in each case at least one abrasive layer, which is arranged in particular on a top side and/or on an underside of the at least one abrasive circle, ensures a long service life. The at least one abrasive layer of the respective abrasive circle comprises an abrasive grain. Each abrasive circle can have an abrasive layer on an underside facing the supporting body and/or on a top side facing away from the supporting body. Preferably, all the abrasive circles have an abrasive layer on the respective top side and/or the respective underside. The abrasive layers of the respective abrasive circle are formed from an identical abrasive grain or a different abrasive grain. Furthermore, the abrasive layers of different abrasive circles are formed from an identical abrasive grain and/or from a different abrasive grain.
Further features, advantages and details of the invention will become apparent from the following description of several exemplary embodiments.
A first exemplary embodiment is described in the following text with reference to
The abrasive circle stack 3 has a number N of abrasive circles S and associated abrasive circle reinforcements A, wherein, for the number N: 1≤N≤9, in particular 2≤N≤8, and in particular 3≤N≤7.
The first abrasive circle s1 with the associated first abrasive circle reinforcement A1 is fastened to the supporting body 2 in the joining region 8. The fastening takes place in particular by adhesive bonding. For example, in the joining region 8, close to the offset 6, an encircling adhesive layer 4 is applied, by means of which the first abrasive circle S 1 including the associated abrasive circle reinforcement A1 is adhesively bonded. The adhesive layer 4 is formed in particular by the bonding agent or resin used to fasten the abrasive circle reinforcement A1 to the abrasive circle S1. The second abrasive circle S2 including the associated second abrasive circle reinforcement A2 is fastened to the first abrasive circle S 1 in the joining region 8. The fastening takes place in particular by adhesive bonding. For example, in a corresponding manner, in the joining region 8, close to the offset 6, an encircling adhesive layer 4 is applied, by means of which the adhesive bonding takes place. The adhesive bonding of the abrasive circle S2 to the underlying abrasive circle S1 takes place in particular with the bonding agent or resin that also serves to fasten the abrasive circle reinforcement A2 to the abrasive circle S2. In a corresponding manner, the third abrasive circle S3 with the associated third abrasive circle reinforcement A3 is fastened the second abrasive circle S2 and the fourth abrasive circle S4 with the associated fourth abrasive circle reinforcement A4 is fastened to the third abrasive circle S3. The first abrasive circle S1 with the associated abrasive circle reinforcement A1 is thus fastened to the supporting body 2, while the further abrasive circles S2 to S4 with the associated abrasive circle reinforcements A2 to A4 are fastened to the respectively underlying abrasive circle S 1 to S3. The abrasive circles S2 to S4 with the associated abrasive circle reinforcements A2 to A4 are thus not directly fastened to the supporting body 2. In the working region 7, the abrasive circles S1 to S4 with the associated abrasive circle reinforcements A1 to A4 are unfastened or not joined, and rest closely on one another in an unlaminated manner.
The supporting body 2 has a supporting-body outside diameter DT and the abrasive circles S1 to S4 with the associated abrasive circle reinforcements A1 to A4 have an abrasive circle outside diameter DS, wherein preferably: 0.1·DX≤DT≤1.2·DS, in particular 0.5·DS≤DT≤1.1·DS, and in particular 0.8·DS≤DT≤DS. In the exemplary embodiment according to
The abrasive circles S 1 to S4 are in the form of abrasive material on bases. The abrasive circles S1 to S4 comprise a backing layer 11, to which an oriented abrasive grain 13 is bonded by means of a bonding agent 12. Formed on the oriented abrasive grain 13 is a top layer 14. The backing layer 11 forms the rear side 10 for fastening the respective abrasive circle reinforcement A1 to A4. The bonding agent 12 with the abrasive grain 13 and the top layer 14 forms a respective abrasive layer 17 of the abrasive circles S1 to S4. The abrasive layer 17 is arranged on a top side, facing away from the supporting body 2, of the respective abrasive circle S1 to S4. Alternatively or additionally, the abrasive layer 17 can be arranged on an underside facing the supporting body 2. Preferably, an abrasive layer 17 is arranged on a top side and on an underside, thereby allowing two-sided working.
The backing layer 11 is configured for example as paper, vulcanized fiber, nonwoven and/or as a backing textile. Preferably, a backing textile comprises polyester fibers, cotton fibers and/or glass fibers. The backing layer 11 is configured in particular as a polyester/cotton blended fabric. The bonding agent 12 is for example a synthetic resin, in particular phenol resin. The oriented abrasive grain 13 is for example a diamond abrasive grain. The abrasive grain 13 is in particular selected from diamond, cubic boron nitride (CBN), silicon carbide (SiC), natural corundum and/or synthetic corundum. The corundum is for example zircon corundum and/or aluminum oxide (Al2O3).
The supporting body 2 is configured for roughing grinding. It comprises an abrasive grain 16 bonded by means of a bonding agent 15, and supporting-body reinforcements 18 and 19. The abrasive grain 16 is for example selected from diamond, cubic boron nitride (CBN), silicon carbide (SiC), natural corundum and/or synthetic corundum. The corundum is for example zircon corundum and/or aluminum oxide (Al2O3). The outer supporting-body reinforcements 18 are arranged next to a top side 20 facing the first abrasive circle S 1 and an underside 21 facing away from the abrasive circle S1, while the inner supporting-body reinforcement 19 is embedded in the supporting body 2 and interspersed with the bonding agent 15 and the abrasive grain 16. The supporting body 2 has, in the direction of the axis M, a supporting-body thickness dT with which the supporting body 2 forms a roughing grinding layer or abrasive layer 22. The supporting-body reinforcements 18, 19 are preferably in the form of a fabric. The fabric comprises in particular glass fibers and/or jute fibers.
A second exemplary embodiment of the invention is described in the following text with reference to
In
The supporting body 2 or the supporting bodies 2, 23 serve(s) according to the invention to support the abrasive circle stack 3 and at the same time itself/themselves for roughing grinding. Since the abrasive circles S1 to S4 with the associated abrasive circle reinforcements A1 to A4 are not joined in the working region 7 and rest closely on one another in an unlaminated manner, targeted wear is allowed, such that abrasive grain 13 that is not worn continuously comes into grinding engagement during the grinding process. As a result of the oriented abrasive grain 13, a high removal capacity and a high level of aggressiveness are achieved, such that the roughing grinding tool 1 is usable in particular also at flat setting angles with the advantages according to the invention. The supporting body 2 itself or the supporting bodies 2, 23 themselves has/have the properties of a roughing grinding tool, in particular of a roughing grinding disk. The roughing grinding tool 1 is configured for example as a roughing grinding disk or as a roughing grinding cup wheel. If necessary, it is possible for an additional paper separating layer to be provided between an abrasive circle reinforcement and one of the adjacent abrasive circles.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2016/069903 | 8/23/2016 | WO | 00 |
