Abrasive tool, in particular abrasive disc

Abstract

This invention relates to a grinding tool (1) comprising a carrier (2) and an abrasive layer (3) disposed on the carrier (2). At least one channel opening (D) is formed on the carrier (2) for observing the workpiece during grinding. The at least one channel opening (D) is surrounded by the carrier (2). The grinding tool (1) has improved grinding performance and improved user convenience.

Description

[0001] The present invention relates to a grinding tool, in particular a grinding disc.

[0002] WO 2018 / 149 483 A1 discloses a grinding tool in the form of a grinding disc. The grinding tool comprises a carrier, on which a layer of abrasive material is directly fixed. In order to form the layer of abrasive material, first an adhesive is applied on the carrier, which is then placed in an electrostatic field, so that abrasive grains are moved towards the carrier due to the effect of the electrostatic field and adhere to the adhesive. Since the carrier itself constitutes the base for the abrasive grains or the layer of abrasive material, the layer of abrasive material can be shaped in any desired three-dimensional shape according to the shape of the carrier.

[0003] The problem addressed by the present invention is to provide a grinding tool having improved grinding performance and improved user convenience. The grinding tool is in particular configured as a grinding disc.

[0004] The problem is solved by a grinding tool having the features of claim 1. At least one passage opening is formed on the carrier. Thus, the at least one passage opening or the respective passage opening is located within the carrier. The circumferential contour of the carrier is in particular not changed by the at least one passage opening or the respective passage opening. The at least one passage opening or the respective passage opening enables an operator to observe a workpiece and flying sparks during the grinding process. The at least one passage opening thereby forms a respective viewing window or a respective observation area, so that the workpiece to be processed can be observed. In this way, the operator can more quickly and easily adjust the angle of attack of the grinding tool with respect to the workpiece, so that the size and / or the position of the working point of the grinding tool is adjusted. The operator can thus use the grinding tool efficiently and minimize wear.

[0005] Since the at least one passage opening or the respective passage opening is surrounded by the carrier, the grinding tool or the carrier exhibits a high stability, even if the at least one passage opening is present. The grinding tool runs very smoothly, which means that the wear is not increased and the service life of the grinding tool is not affected.

[0006] Furthermore, the at least one passage opening or the respective passage opening enables an improved removal of grinding dust during the grinding process. The grinding dust generated during the grinding process can be removed more simply and more quickly by means of the at least one passage opening or by means of the respective passage opening by means of an air flow into the surroundings, so that the grinding dust does not interfere with the ongoing grinding work. The grinding performance of the grinding tool is thus improved.

[0007] The at least one passage opening or the respective passage opening can be of a symmetrical and / or of an asymmetrical configuration. The at least one passage opening or the respective passage opening is preferably symmetrical with respect to at least one axis of symmetry.

[0008] The carrier is configured to be in particular unitary and / or in particular non-metallic and / or in particular electrically insulating. The carrier comprises for example at least one material selected from the group comprising vulcanized fibers, cotton, plastic materials, glass fibers and carbon fibers. The carrier preferably adopts a unitary plastic carrier. The plastic carrier is produced for example by an injection molding process, an additive manufacturing process or a subtractive manufacturing process. The carrier has in particular a three-dimensional shape. The carrier is preferably curved in a radial direction and / or in a circumferential direction with respect to the axis of rotation of the grinding tool. The carrier has in particular a geometrically defined shape and can have any desired shape or profile in the axial direction. In the case of the grinding tool being in the form of a grinding disc, the carrier is in particular configured as a carrier plate or carrier disc. The carrier of the grinding disc is preferably made in one piece from a plastic material.

[0009] The grinding tool comprises a connecting element for clamping the grinding tool in a grinding tool drive and / or for the rotational drive of the grinding tool about an axis of rotation by means of the grinding tool drive. The connecting element is for example in the form of a hub or a shaft. The grinding tool configured as a grinding disc preferably comprises a connecting element in the form of a hub which is arranged in the clamping region of the carrier plate. The grinding tool has a grinding side which faces the workpiece to be machined and a drive side which faces the grinding tool drive.

[0010] The abrasive layer comprises at least abrasive particles and a make coat for fixing the abrasive particles. The make coat comprises a binder or adhesive. The binder serves to fix the abrasive particles. The abrasive layer preferably comprises a size coat. The size coat is applied to the fixed abrasive particles. The size coat comprises a binder and optionally a filler having a grinding activity. The binder of the size coat can be the same or different from the binder for fixing the abrasive particles. The abrasive layer can be fixed directly to the carrier or indirectly via a backing layer. In the region of the at least one channel opening there is no abrasive layer.

[0011] The abrasive layer has in particular a three-dimensional shape. The abrasive layer is preferably curved in a radial direction and / or in a circumferential direction with respect to the axis of rotation of the grinding tool. The three-dimensional shape of the abrasive layer corresponds in particular to a part of the three-dimensional shape surface or the bonding surface of the carrier.

[0012] The abrasive particles preferably have a geometrically defined cutting edge. The abrasive particles are in particular configured as triangles. At least a part of the abrasive particles is preferably oriented in an aligned manner with respect to one another and / or with respect to the bonding surface of the carrier.

[0013] The grinding tool according to claim 2 ensures improved grinding performance and greater user convenience. A discontinuous central region is provided radially between the clamping region and the continuous outer region. A continuous inner region may be provided radially between the clamping region and the discontinuous central region. The clamping region and / or the continuous inner region and / or the discontinuous central region and / or the continuous outer region are particularly in a ring-shaped structure and / or concentrically arranged relative to the axis of rotation.

[0014] A continuous inner region radially surrounds the clamping region. A discontinuous central region radially surrounds both the clamping region and the continuous inner region. A continuous outer region radially surrounds the clamping region, the continuous inner region, and the discontinuous central region. The discontinuous central region is interrupted by at least one channel opening in the radial and / or circumferential directions. The continuous outer region stabilizes the discontinuous central region, thereby stabilizing the carrier or grinding tool. Therefore, the grinding tool operates very smoothly, ensuring that wear on the grinding tool does not increase and its service life is not affected.

[0015] The discontinuous central region begins radially from the inner end of at least one channel opening and ends radially from the outer end of at least one channel opening. The continuous outer region has a dimension A in the radial direction. A Size A A The distance from the circumferential contour of the grinding tool or carrier in the radial direction corresponding to at least one channel opening or each channel opening.

[0016] The abrasive layer is disposed in the discontinuous central region of the carrier, particularly covering its entire surface. The abrasive layer may also be disposed at least on a portion of the surface of a continuous internal region and / or a continuous external region.

[0017] The grinding tool specifically includes a connecting element disposed or formed within the clamping area. The connecting element is disposed or formed concentrically with the axis of rotation.

[0018] The grinding tool according to claim 3 ensures improved grinding performance and greater user convenience. Because the continuous outer region's circumferential profile has a constant direction of curvature, the carrier has no recesses in the radial direction. This ensures high stability and smooth operation. The continuous outer region is particularly annular in structure. The continuous outer region or the circumferential profile of the carrier is particularly circular. The circumferential profile is particularly concentric with the axis of rotation of the carrier or grinding tool.

[0019] The grinding tool according to claim 4 ensures improved grinding performance and greater user convenience. Because the abrasive layer is disposed in a discontinuous central region, discontinuous abrasive regions are formed. These discontinuous abrasive regions are interrupted in the radial and / or circumferential directions by at least one channel opening. No abrasive layer is present within the region of the at least one channel opening, such that each channel opening forms an observation window or observation area. Therefore, each observation window or observation area discontinuously interrupts the abrasive layer in the radial and / or circumferential directions.

[0020] The abrasive layer may be disposed at least on a portion of the surface of a continuous inner region and / or a continuous outer region of the carrier, thereby forming a continuous inner abrasive region and / or a continuous outer abrasive region. The continuous inner abrasive region and / or the continuous outer abrasive region are particularly annular and disposed directly adjacent to the discontinuous abrasive region in the radial direction, such that the abrasive layer is continuously formed in the radial direction outside at least one channel opening. The abrasive layer is preferably disposed over the entire surface of the continuous inner region and / or the continuous outer region.

[0021] The grinding tool according to claim 5 ensures improved grinding performance and greater user convenience. At least one or more reinforcing members are disposed within the boundary region surrounding at least a portion of the relevant channel opening. At least one or more reinforcing members are disposed on the drive side of the grinding tool or carrier. At least one or more reinforcing members particularly completely surround the boundary region of the relevant channel opening. At least one or more reinforcing members particularly form an integral part with the carrier.

[0022] The carrier or grinding tool is reinforced and stabilized within the relevant channel opening area by the at least one or more reinforcing members. This ensures compliance with relevant safety regulations and guarantees highly smooth operation. Furthermore, as the grinding tool rotates about its axis of rotation, at least one reinforcing member generates a negative pressure on the drive side of the grinding tool. Due to this negative pressure on the drive side, an airflow is generated through the at least one or more channel openings, thereby achieving improved debris removal and providing a cooling effect.

[0023] The grinding tool according to claim 6 ensures improved grinding performance and greater user convenience. Relative to a predetermined direction of rotation of the grinding tool, each leading edge is positioned upstream of the relevant channel opening, while each trailing edge is positioned downstream of the relevant channel opening in the direction of rotation. The trailing and leading edges are, in particular, part of a reinforcing member formed on the carrier around the boundary region of the relevant channel opening. The leading and trailing edges are positioned on the drive side of the carrier or the grinding tool. The leading and trailing edges are, in particular, integrally formed with the carrier.

[0024] Due to the leading and trailing edges, when the grinding tool rotates about its axis of rotation in a predetermined direction, a negative pressure is generated on the drive side, creating an airflow from the grinding side through the corresponding channel openings to the drive side. This airflow removes grinding debris and provides cooling. Because each trailing edge is raised relative to the leading edge, the airflow is deflected at the trailing edges, particularly towards the corresponding recesses. In this way, grinding debris can be discharged from the grinding tool into the surrounding environment in the desired manner.

[0025] The grinding tool according to claim 7 ensures improved grinding performance and greater user convenience. At least one or more recesses are provided on the drive side of the grinding tool. At least one or more recesses are located circumferentially next to the associated channel opening of the grinding tool. At least one or more recesses are preferably located between two circumferentially adjacent channel openings. At least one or more recesses extend, particularly radially, to the circumferential profile of the carrier or grinding tool.

[0026] Airflow from at least one or more channel openings can flow along at least one or more recesses toward the surrounding environment. This allows abrasive debris to be discharged from the grinding side of the grinding tool into the surrounding environment in the desired manner. Furthermore, the at least one or more recesses reduce flow resistance on the drive side, thereby ensuring a high degree of cooling effect on the airflow. The at least one or more recesses are particularly groove-like, for example, bead-like. The at least one or more recesses have a width defined in the circumferential direction, which gradually widens in the radial direction. Each channel opening is preferably associated with a reinforcement and / or a recess.

[0027] The grinding tool according to claim 8 ensures improved grinding performance and greater user convenience. A plurality of channel openings are preferably formed on the carrier. The construction of the plurality of channel openings can be the same and / or different. The plurality of channel openings are preferably formed around the axis of rotation at the same angular distance. The carrier is particularly rotationally symmetric about the axis of rotation, with a rotational symmetry angle of Δφ. For this rotational symmetry angle Δφ, the following formula applies: Δφ = 360° / N. Each channel opening has an inner end and an outer end. The inner ends of these channel openings preferably maintain the same distance from the axis of rotation in the radial direction. The outer ends of these channel openings correspondingly maintain the same distance from the axis of rotation in the radial direction.

[0028] The grinding tool according to claim 9 ensures improved grinding performance and greater user convenience. Area ratio F D / F S On the one hand, it ensures a sufficient observation area for workpiece observation through at least one channel opening; on the other hand, it ensures a sufficiently large abrasive layer. Ratio F DThe larger / Fs is, the larger the observation area. Conversely, the larger the abrasive layer area, the larger the ratio F. D / F S The smaller the area F, the better. If multiple channel openings are formed on the carrier, the area F will be smaller. D This represents the sum of the sub-areas of all channel openings.

[0029] The grinding tool according to claim 10 ensures improved grinding performance and greater user convenience. Ratio A D / A S On the one hand, this ensures that operators can fully observe the workpiece or grinding area; on the other hand, it ensures that the stability of the carrier or grinding tool within the grinding area is maintained. Ratio A D / A S The larger the value, the better the operator can observe the grinding area. Conversely, the higher the stability, the better the ratio A. D / A S The smaller it is.

[0030] The grinding tool according to claim 11 ensures improved grinding performance and greater user convenience. Radial distance A A The radial dimension corresponding to the continuous outer region of the carrier. Ratio A A / A D On the one hand, this ensures that operators can fully observe the workpiece or grinding area; on the other hand, it does not affect the stability of the carrier or grinding tool. Ratio A A / A D The larger the value of A, the larger the size of the continuous outer region relative to at least one channel opening in the radial direction, and the higher the stability. Conversely, the larger the size of at least one channel opening, the easier it is to observe the workpiece or grinding area, and the higher the ratio A. A / A D The smaller it is.

[0031] The grinding tool according to claim 12 ensures improved grinding performance and greater user convenience. Angle α aligns at least one channel opening or all channel openings with the set angle of attack of the grinding tool. Angle α is defined as the angle at point P between the radial direction and the main extension direction of at least one channel opening or all channel openings. Point P is located within each channel opening D and is the point closest to the axis of rotation in the radial direction. If multiple channel openings are formed on the carrier, these channel openings may have the same angle α and / or different angles α.

[0032] The grinding tool according to claim 13 ensures improved grinding performance and greater user convenience. The ratio L / B enables at least one channel opening or individual channel openings to be adapted to the desired observation area and the necessary stability of the grinding tool. At least one channel opening or individual channel openings are preferably configured as elongated holes, wherein: L / B > 1, particularly L / B ≥ 1.5, particularly L / B ≥ 2.

[0033] The grinding tool according to claim 14 ensures improved grinding performance and greater user convenience. The abrasive grains are directly fixed to the carrier via a primer. The primer contains an adhesive or binder for fixing the abrasive grains to the carrier. To manufacture this grinding tool, an adhesive or binder is coated onto the carrier, thereby forming an adhesive surface. For example, with the aid of an electrostatic field, the abrasive grains are transported to the adhesive surface and adhere there. After the adhesive or coupling agent cures, the abrasive grains are fixed to the adhesive surface or the carrier surface area. Thus, the carrier itself constitutes the base for the abrasive grains or abrasive layer. The abrasive grains can be coated onto the carrier in a single layer or multiple layers. The abrasive layer preferably contains only one layer of abrasive grains directly fixed to the carrier.

[0034] For information on abrasive grains being directly attached to a carrier and abrasive tools manufactured in this manner, please refer to WO 2018 / 149 483 A1, the contents of which are incorporated herein by reference.

[0035] The grinding tool according to claim 15 ensures improved grinding performance and greater user convenience. The abrasive layer is indirectly fixed to the carrier via a backing layer. The backing layer is particularly annular and / or integral in structure. The backing layer particularly comprises at least one material selected from the group consisting of vulcanized fibers, rubber, and paper. The backing layer is fixed to the carrier by an adhesive or bonding agent. The backing layer is preferably fixed to the carrier over at least 80% of its area, particularly at least 90% of its area, and especially at least 95% of its area. The abrasive layer is fixed to the side of the backing layer away from the carrier. The abrasive layer and the backing layer particularly form a coated abrasive and are fixed to the carrier.

[0036] The following description of preferred exemplary embodiments will reveal further features, advantages, and details of the present invention. (See accompanying drawings.) Figure 1 This is a side view of a grinding disc-shaped grinding tool according to a first exemplary embodiment. Figure 2 yes Figure 1 The top view of the grinding disc shown is intended to illustrate the abrasive layer directly fixed to the carrier and the channel openings formed in the carrier. Figure 3 yes Figure 1The rear view of the grinding disc shown is intended to illustrate the reinforcement and recess in the boundary region surrounding the channel opening. Figure 4 It is along Figure 3 First cross-sectional view of the grinding disc taken along section line IV-IV. Figure 5 It is along Figure 3 Second sectional view of the grinding disc, taken by the central section line VV. Figure 6 yes Figure 5 Enlarged view of detail VI. Figure 7 This is a top view of the grinding disc-shaped grinding tool according to the second exemplary embodiment. Figure 8 It is along Figure 7 A cross-sectional view of the grinding disc taken along section line VIII-VIII. Figure 9 It is along Figure 7 A magnified sectional view of the grinding disc in one of the channel opening areas, taken along the central section line IX–IX.

[0037] The following is for reference. Figures 1 to 6 A first exemplary embodiment of the present invention is described. For example... Figures 1 to 6 As shown, the grinding tool 1 is constructed as a grinding disc. The grinding tool 1 includes a carrier 2 and an abrasive layer 3 disposed thereon. The grinding tool 1 is used to grind a workpiece W. The workpiece W is, in particular, metallic. The workpiece W is shown as an example. Figure 4 In. Figure 1 and Figure 2 In the image, only a portion of the abrasive layer 3 is shown.

[0038] The grinding tool 1 forms a rotation axis M. Along the rotation axis M, the grinding tool 1 defines a grinding side S and a driving side A. During the grinding process, the grinding tool 1 is driven to rotate about the rotation axis M by a grinding tool drive device (not shown). For this purpose, the grinding tool 1 includes a connecting element 4. The connecting element 4 is in the form of a hub and is arranged concentrically with the rotation axis M. On the grinding side, an abrasive layer 3 is disposed on a carrier 2. During the grinding process, the grinding side S faces the workpiece W. Conversely, during the grinding process, the driving side A faces the grinding tool drive device.

[0039] The carrier 2 takes the form of a support plate. The carrier 2 is integrally made of a non-metallic material (e.g., plastic). The carrier 2 defines a circular circumferential profile U. K .

[0040] In this exemplary embodiment, six channel openings are formed in the carrier 2. These channel openings are collectively referred to as channel openings D, and individually as channel openings D1, D2, D3, D4, D5, and D6. The channel openings D extend through the carrier 2 axially (i.e., in the direction of the rotation axis M). The channel openings D facilitate observation of the workpiece W during the grinding process. Therefore, the channel openings D form observation windows or observation areas. For the number N of channel openings D, the following ranges are generally applicable: 1 ≤ N ≤ 24, particularly 2 ≤ N ≤ 12, and particularly 3 ≤ N ≤ 8.

[0041] Along the radial direction R, the carrier 2 sequentially forms a clamping region 5, a continuous internal region 6, a discontinuous central region 7, and a continuous external region 8.

[0042] The clamping area 5 is a planar structure. In the clamping area 5, the connecting element 4 is set or configured concentrically with the rotation axis M.

[0043] A continuous inner region 6 surrounds the clamping region 5. The continuous inner region 6 is annular and concentrically arranged relative to the axis of rotation M. The continuous inner region 6 extends radially from the clamping region 5 to the discontinuous central region 7 or to the channel opening D. The continuous inner region 6 forms a shoulder K, such that the discontinuous central region 7 and the continuous outer region 8 are axially spaced from the clamping region 5. The shoulder K accommodates a clamping nut for connecting the grinding tool 1 to the grinding tool drive; the nut is located within the receiving space formed by the shoulder K, thus concealing it. This ensures that the clamping nut does not contact the workpiece W during grinding. Furthermore, the grinding tool drive is spaced from the channel opening D by the shoulder K.

[0044] A discontinuous central region 7 surrounds the clamping region 5 and the continuous inner region 6. The discontinuous central region 7 is annular and concentrically arranged relative to the rotation axis M. The discontinuous central region 7 extends radially from the inner end of the channel opening D to the outer end of the channel opening D. The discontinuous central region 7 is interrupted by the channel opening D in the circumferential direction C and the radial direction R around the rotation axis M. Due to the presence of the continuous inner region 6 and the continuous outer region 8, the channel opening D is surrounded by the carrier 2.

[0045] A continuous outer region 8 surrounds the clamping region 5, the continuous inner region 6, and the discontinuous central region 7. The continuous outer region 8 is annular and concentrically arranged relative to the axis of rotation M. The continuous outer region 8 extends radially R from the outer end of the channel opening D to the circumferential profile U. K .

[0046] Circular outline U KDue to its circular shape, it has a constant curvature direction relative to the axis of rotation M. Because the channel opening D does not interrupt the continuous outer region 8 and the circular profile U... K Furthermore, the carrier 2 surrounds the channel opening D, thus ensuring the continuity of the outer region 8 and the circumferential profile U. K The constant direction of curvature.

[0047] Channel openings D1 to D6 are arranged around the axis of rotation M at the same angle or angular spacing Δφ. For the angular spacing Δφ, the following formula applies: Δφ = 360° / N, where N represents the number of channel openings D. In this exemplary embodiment, the following provisions apply: N = 6, Δφ = 60°. Channel openings D1 to D6 have the same arrangement and structure, such that the carrier 2 is rotationally symmetrical with respect to the angle or angular spacing Δφ = 60°.

[0048] The radial distance between each inner end of the channel opening D and the axis of rotation M is R. I The radial distance between each outer end of the channel opening D and the rotation axis M is R. A In the radial direction R, the size of the channel opening D is A. D = R A - R I In each case, the channel opening D has a main extending direction H, which forms an angle α with the radial direction R at the intersection point P. The intersection point P is located within each channel opening D and is the point on the radial direction R closest to the axis of rotation M. The angle α is relative to the predetermined rotation direction D of the grinding tool 1. R The opposite direction is defined. For the included angle α, the following ranges generally apply: 0° ≤ α ≤ 60°, especially 10° ≤ α ≤ 50°, and especially 20° ≤ α ≤ 40°. Generally, the included angle α of the openings D of each channel can be the same and / or different.

[0049] The channel opening D has a length L along its main extension direction H and a width B perpendicular to the main extension direction H. For the aspect ratio L / B, the following ranges are generally applicable: 0.5 ≤ L / B ≤ 10, particularly 1 ≤ L / B ≤ 8, particularly 2 ≤ L / B ≤ 6. In this exemplary embodiment, the channel opening D is elongated. For the shape of elongated holes, the following ratios are particularly applicable: L / B > 1, particularly L / B ≥ 1.5, particularly L / B ≥ 2. Each elongated hole has rounded corners.

[0050] The continuous outer region 8 extends from the outer end of the channel opening D to the circumferential profile U. K In the radial direction R, the circumferential profile U K The radial distance from the axis of rotation M is R UFor the continuous outer region 8, the dimension A in the radial direction R. A The following formula applies: A A = R U – R A The radial dimension A of the continuous outer region 8 A Therefore, corresponding to the channel opening D and the circumferential profile U K The radial distance between them. For the ratio A A / A D This typically applies to the following range: 0.05 ≤ A A / A D ≤ 0.5, especially 0.1 ≤ A A / A D ≤ 0.4, especially 0.15 ≤ A A / A D ≤ 0.3.

[0051] Abrasive layer 3 is disposed on the discontinuous central region 7, the continuous outer region 8, and a portion of the continuous inner region 6. There is no abrasive layer 3 in the channel opening D region. Figures 1 to 6 In the diagram, only a portion of the abrasive layer 3 is shown. The abrasive layer 3 includes a base coat 9, abrasive grains 10, and a cap coat 11. The base coat 9 directly attaches the abrasive grains 10 to the carrier 2. The base coat 9 includes an adhesive that provides a bonding surface for the abrasive grains 10. The cap coat 11 is applied to the abrasive grains 10 and includes an adhesive and optional abrasive-active filler. The base coat 9 and the cap coat 11 may contain the same or different adhesives.

[0052] During the production of the grinding tool 1, abrasive grains 10 are conveyed to the substrate 9 or the bonding surface, for example, via an electrostatic field. Thus, the central longitudinal axis of the abrasive grains 10 is oriented relative to the carrier 2 and to each other. The cross-section of the abrasive grains 10 is triangular. Therefore, the abrasive grains 10 preferably have geometrically defined cutting edges.

[0053] The abrasive layer 3 has a three-dimensional shape. The abrasive layer 3 is curved in both the circumferential direction C and the radial direction R. The abrasive layer 3 has a ring-shaped structure. Because the abrasive layer 3 is arranged in a portion of the continuous inner region 6, the entire discontinuous central region 7, and the entire continuous outer region 8, the abrasive layer 3 forms a continuous inner abrasive region S. I Intermittent central abrasive region S M and continuous external abrasive zone S A Intermittent central abrasive region S M Corresponding to the discontinuous central region 7 of carrier 2. Continuous external abrasive region S. A Corresponding to the continuous outer region 8 of carrier 2. Continuous inner abrasive region S. IA ring-shaped portion corresponding to the continuous inner region 6 faces the channel opening D in the radial direction R.

[0054] Channel openings D1 to D6 each have a corresponding area F D1 To F D6 The total area of ​​the channel openings D1 to D6 is F. D , where F D = F D1 + F D2 + F D3 + F D4 + F D5 + F D6 The area of ​​abrasive layer 3 is F. S For the ratio F D / F S This typically applies to the following range: 0.05 ≤ F D / F S ≤ 0.8, especially 0.1 ≤ F D / F S ≤ 0.6, especially 0.15 ≤ F D / F S ≤ 0.4.

[0055] The abrasive layer 3 is located radially R from the axis of rotation M at a distance R. S The position extends to a distance of R U The circumferential contour U K In the radial direction R, the size of the abrasive layer 3 is A. S = R U – R S For ratio A D / A S This typically applies to the following range: 0.2 ≤ A D / A S ≤ 1, especially 0.3 ≤ A D / A S ≤ 0.9, especially 0.4 ≤ A D / A S ≤ 0.8.

[0056] Each channel opening D1 to D6 has reinforcements V1 to V6 and recesses T1 to T6 thereon. These reinforcements are denoted by V1 to V6 respectively, and collectively by V. Correspondingly, these recesses are denoted by T1 to T6 respectively, and collectively by T. The reinforcements V1 to V6 are arranged within the corresponding boundary regions U1 to U6 surrounding the respective channel openings D1 to D6. These boundary regions are denoted by U1 to U6 respectively, and collectively by U.

[0057] These reinforcing members V are identical in construction and, in each case, are arranged within the relevant boundary region U surrounding the relevant channel opening D. The reinforcing member V is arranged on the drive side A of the carrier 2. The reinforcing member V is part of and formed by the carrier 2. In the region of the reinforcing member V, the material thickness of the carrier 2 is greater than that of the recessed region T. The reinforcing member V completely surrounds the boundary region of each relevant channel opening D. This is in the circumferential direction C or the predetermined rotational direction D. R When viewed from above, each reinforcing member V forms a leading edge 12 and a trailing edge 13. This is relative to the predetermined rotational direction D of the grinding tool 1. R The leading edge 12 is located upstream of the trailing edge 13. The trailing edge 13 is higher than the leading edge 12.

[0058] The recessed portion T relative to the predetermined rotation direction D R Arranged upstream of their respective channel openings D and adjacent to their respective leading edges 12. The recess T is formed by a carrier 2, the material thickness of which is relatively small in the region of the recess T. The width of the recess T in the circumferential direction is C, gradually widening in the radial direction R. The recess T preferably has a V-shaped cross-section.

[0059] The working mode of grinding tool 1 is described in detail below.

[0060] The grinding tool 1 is typically connected to a grinding tool drive unit (not shown in more detail in the figure), for example, to an angle grinder, via a connecting element 4. For this purpose, the drive shaft of the grinding tool drive unit passes through the connecting element 4, which is configured as a hub, and the grinding tool 1 is connected to the drive shaft of the grinding tool drive unit in a clamping area 5 via a clamping nut. The drive side A faces the grinding tool drive unit, while the grinding side S faces the workpiece W to be processed.

[0061] The grinding of workpiece W is performed by an operator. To do this, the operator guides the grinding tool 1 close to workpiece W and brings the abrasive layer 3 into contact with it. Because the channel openings D form an observation area, the operator can observe the workpiece W and the splashing sparks during the grinding process. This allows the operator to optimize the angle of attack of the grinding tool 1 relative to the workpiece W, thereby adjusting the size and / or position of the working point of the abrasive layer 3. For example, the angle of attack or working point has been adjusted to its optimal value when the splashing sparks pass approximately from the center of each channel opening D. Since the channel openings D are surrounded by the carrier 2, the continuous outer region 8 acts to stabilize the carrier 2 or the grinding tool 1. The abrasive layer 3 is arranged in the continuous outer abrasive region S. A Therefore, the continuous outer region 8 of the carrier 2 can also be used for grinding in a similar way.

[0062] When the grinding tool 1 rotates around the axis of rotation M, a negative pressure is generated on the driving side A relative to the grinding side S due to the action of the reinforcing member V. Because of this negative pressure, air flows from the grinding side S through its respective channel opening D to the driving side A. Figure 3 In the diagram, airflow F is illustrated using channel opening D1 as an example. Starting from their respective channel openings D, air escapes from the drive side A along their respective associated recesses T into the surrounding environment. For this purpose, due to the higher trailing edge 13, the air is deflected towards the respective leading edge 12 and the respective associated recesses T. Airflow F carries abrasive debris from the grinding side S through the channel openings D to the drive side A, and further into the surrounding environment, while simultaneously cooling the abrasive layer 3. In this respect, the grinding performance of the grinding tool 1 is improved.

[0063] Since the abrasive layer 3 is applied directly to the carrier 2, for example by electrostatic coating in an electrostatic field, the abrasive layer 3 can be shaped into any three-dimensional form or bent as needed, and the abrasive grains 10 are oriented relative to the carrier 2 and to each other. Thus, the grinding tool 1, combined with the channel opening D surrounded by the carrier 2, exhibits improved grinding performance and enhanced user convenience. Due to the presence of the continuous outer region 8 and the reinforcing member V, the grinding tool 1 exhibits user-friendly, smooth operation characteristics, preventing hammering during grinding and thus reducing wear on the grinding tool 1 and operator fatigue. Specifically, the grinding tool 1 can shorten processing time, thereby reducing operator fatigue.

[0064] The following is for reference. Figures 7 to 9 A second exemplary embodiment of the present invention is described. Unlike the first exemplary embodiment, the abrasive layer 3 is fixed to the carrier 2 by a backing layer 14. Figure 7 In the diagram, only a portion of the abrasive layer 3 is shown. The abrasive layer 3 is fixed to the backing layer 14 and forms a coated abrasive. The backing layer 14 is a one-piece annular structure. The abrasive layer 3 is fixed to the backing layer 14, which in turn is fixed to the carrier 2 via a side away from the abrasive layer 3. The entire surface of the backing layer 14 is connected to the carrier 2. The backing layer 14 is fixed to a discontinuous central region 7, as well as a portion of a continuous inner region 6 and a portion of a continuous outer region 8. For example, the backing layer 14 is made of vulcanized fiber, rubber, or paper. The backing layer 14 is fixed to the carrier 2 by an adhesive. In this case, the abrasive layer 3 will not bend or deform, and therefore will not break. The backing layer 14 has channel openings, the number, arrangement, and construction of which correspond to the channel openings D of the carrier 2, thereby preserving the observation area formed by the channel openings D. For further details on the structure and operating modes of the grinding tool 1, please refer to the preceding exemplary embodiments.

Claims

1. A grinding tool, particularly a grinding disc, comprising: - Carrier (2), and - An abrasive layer (3) is disposed on the carrier (2). Its features are, At least one channel opening (D) is formed on the carrier (2) for observing the workpiece (W) during the grinding process, and The at least one channel opening (D) is surrounded by the carrier (2).

2. The grinding tool according to claim 1, characterized in that, The carrier (2) includes: - Clamping area (5), used to rotate the grinding tool (1) about the rotation axis (M) by the grinding tool drive device, - The central region (7) is interrupted by the at least one channel opening (D) and surrounds the clamping region (5), and - A continuous outer region (8) surrounding a discontinuous central region (7).

3. The grinding tool according to claim 2, characterized in that, The continuous outer region (8) forms a circumferential profile (U). K The circumferential profile (U) K It has a constant curvature direction relative to the axis of rotation (M).

4. The grinding tool according to claim 2 or 3, characterized in that, The abrasive layer (3) is disposed at least in the discontinuous central region (7).

5. The grinding tool according to at least one of the preceding claims, characterized in that, The carrier (2) forms at least one reinforcing member (V) arranged around the at least one channel opening (D).

6. The grinding tool according to at least one of the preceding claims, characterized in that, The carrier (2) forms a leading edge (12) and a trailing edge (13) within a boundary region (U) surrounding the at least one channel opening (D), wherein the trailing edge (13) is raised relative to the leading edge (12).

7. The grinding tool according to at least one of the preceding claims, characterized in that, The carrier (2) has at least one recess (T) formed next to at least one channel opening (D).

8. The grinding tool according to at least one of the preceding claims, characterized in that, For the number N of the at least one channel opening (D), the following range applies: 1 ≤ N ≤ 24, especially 2 ≤ N ≤ 12, especially 3 ≤ N ≤ 8.

9. The grinding tool according to at least one of the preceding claims, characterized in that, The at least one channel opening (D) has an area F D And the abrasive layer (3) has an area F S Where 0.05 ≤ F D / F S ≤0.8, especially 0.1 ≤ F D / F S ≤ 0.6, especially 0.15 ≤ F D / F S ≤ 0.

4.

10. The grinding tool according to at least one of the preceding claims, characterized in that, The at least one channel opening (D) has a dimension A in the radial direction relative to the axis of rotation (M). D The abrasive layer (3) has a dimension A in the radial direction relative to the axis of rotation (M). S Where 0.2 ≤ A D / A S ≤ 1, especially 0.3 ≤ A D / A S ≤0.9, especially 0.4 ≤ A D / A S ≤ 0.

8.

11. The grinding tool according to at least one of the preceding claims, characterized in that, The at least one channel opening (D) has a dimension A in the radial direction relative to the axis of rotation (M). D And for the at least one channel opening (D) at a distance from the circumferential profile (U) of the carrier (2) K radial distance A A It satisfies the following range: 0.05 ≤ A A / A D ≤ 0.5, especially 0.1 ≤ A A / A D ≤ 0.4, especially 0.15 ≤ A A / A D ≤ 0.

3.

12. The grinding tool according to at least one of the preceding claims, characterized in that, The at least one channel opening (D) defines a main extension direction (H), wherein the angle α between the radial direction (R) and the main extension direction (H) satisfies the following range: 0° ≤ α ≤ 60°, particularly 10° ≤ α ≤ 50°, and particularly 20° ≤ α ≤ 40°.

13. The grinding tool according to at least one of the preceding claims, characterized in that, The at least one channel opening (D) has a length L in the main extension direction (H) and a width B in a direction perpendicular to the main extension direction (H), wherein 0.5 ≤ L / B ≤ 10, particularly 1 ≤ L / B ≤ 8, particularly 2 ≤ L / B ≤ 6.

14. The grinding tool according to at least one of the preceding claims, characterized in that, The abrasive layer (3) is directly fixed on the carrier (2).

15. The grinding tool according to at least one of claims 1 to 12, characterized in that, The abrasive layer (3) is fixed on the backing layer (14), and the backing layer (14) is fixed on the carrier (2).

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