ROLLING GRINDER WITH PRESS FIT BETWEEN ROLLER AND AXLE

Description

[0001] The present invention relates to a method for producing a roller grinder with at least one grinding or polishing surface for grinding and / or polishing a cutting tool, wherein the roller grinder is essentially formed from two rollers, a handle body to be arranged between the rollers and rotatable relative thereto, and an axle to be rotatably mounted in the handle body.

[0002] Such a roller grinder is known, for example, from EP 3 278 928 A2. This roller grinder is designed to be brought into contact with the cutting edge of the cutting tool to be ground with its grinding or polishing surface and moved along the cutting edge over a flat surface. The front grinding or polishing surface rotates in a grinding plane oriented perpendicular to the surface and removes material from the cutting edge.

[0003] In the roller grinder known from EP 3 278 928 A2, the rollers and grinding or polishing discs are screwed to the axle, allowing the roller grinder to be easily disassembled into its individual components. When removing the grinding or polishing discs from the axle, the user must hold the rollers firmly, as they will otherwise detach from the axle. Being able to disassemble the roller grinder makes cleaning easier, but makes handling more difficult for the user.

[0004] The present invention is based on the object of improving the known roller grinder in such a way that the intended operation of the roller grinder is designed to be user-friendly and overall easier.

[0005] To achieve this object, the present invention provides the method for producing a roller grinder according to claim 1. The method according to the invention serves to produce a roller grinder with at least one grinding or polishing surface for grinding and / or polishing a cutting tool, wherein the roller grinder is essentially formed from two rollers, a handle body to be arranged between the rollers and rotatable relative thereto, and an axle to be rotatably mounted in the handle body. According to the invention, each of the rollers is non-positively connected to the axle. As a result, the rollers, the handle body, and the axle form an integral unit and ideally cannot be separated from one another without causing damage. As a result, the roller grinder according to the invention can be produced with little effort and is overall user-friendly, since the components of the roller grinder are held together captively.

[0006] According to the invention, each of the rollers is connected to the axle by press-fitting. After press-fitting, an interference fit is created at the connection points between the roller and the axle. This allows longitudinal and transverse forces to be transmitted force-locking. This creates a cylindrical interference fit between the roller and the axle. To achieve a longitudinal interference fit, the roller is pressed onto the axle under high axial force (for example, using a hydraulic press). The average surface roughness of the roller and / or axle is preferably in the range Rz of 3 to 10 µm. To facilitate press-fitting, an insertion bevel or chamfer on the axle and / or the roller is advantageous.

[0007] Advantageous further training is the subject of dependent claims.

[0008] It can be advantageous if one or both of the rollers are connected to the axle by force-fitting only. This purely force-fitting connection between each roller and the axle requires no separate fastening device. This reduces the number of required components and, accordingly, the cost of manufacturing the roller grinder.

[0009] It may be useful for one or both of the rollers to be connected to the axle at a temperature difference between the axle and the roller. For example, before assembly, the roller is heated and / or the axle is cooled. This causes the roller to expand or the axle to shrink, allowing the two parts to be joined with little or no force. During subsequent temperature equalization, the compression occurs, with the surface roughness largely retained, resulting in a much tighter fit than with a longitudinal interference fit.

[0010] It can prove practical if one or both of the rollers are placed on the axle or inserted into the axle. In an advantageous embodiment, the roller has a bore, in particular a through bore, and the axle has a bearing section that fits into the bore. The roller forms the "female" component and the axle the "male" component. However, it is also possible for the axle to form the "female" component and have a bore, while the roller, as the "male" component, includes a bearing section that fits into the bore.

[0011] It can be helpful to use a stepped axle with a center section and two stepped bearing sections at the ends. For axial positioning of the roller relative to the axle, the center section is advantageous as a position limiter, for example, in the form of a shoulder.

[0012] It can be advantageous if a rolling bearing and one of the track rollers, and optionally a spacer element, are arranged on each bearing section, preferably in such a way that the rolling bearing is supported axially with its inner ring on the center section of the axle and / or the spacer element is axially fixed between the rolling bearing and the track roller. The center section of the axle is used as a position limit for the track roller on the axle. This design allows the position of the track roller relative to the axle to be adjusted particularly precisely.

[0013] It may be useful to secure the outer ring of the rolling bearing to the grip body with a force-locking and / or positive fit. This allows the position of the axis relative to the grip body to be precisely adjusted.

[0014] It may be advantageous if one or both of the rollers have a grinding or polishing surface permanently attached thereto, preferably on the front side. The grinding or polishing surface is preferably formed integrally with the roller or permanently connected to it. The grinding or polishing surface is particularly preferably formed as a coating, in particular as a ceramic coating. In this variant, the roller grinder has a minimal number of components. This simplifies production and handling for the user.

[0015] However, it can also be practical to attach a grinding or polishing disc with a grinding or polishing surface to one or both of the rollers, preferably a removable one. This option is particularly suitable for more experienced users who want to use interchangeable grinding or polishing discs. This makes the roller sander more versatile.

[0016] Preferably, the handle body has at least one of the following features. The handle body is made of plastic and / or metal and / or wood, preferably oak, walnut, beech, or spruce, preferably in one piece. The handle body is designed as a cylinder, preferably as a hollow cylinder.

[0017] An independent aspect of the present invention relates to a roller grinder with two rollers and a handle body arranged therebetween, wherein the rollers are non-positively connected to an axle rotatably mounted in the handle body. The rollers each have a grinding or polishing surface on their front sides.

[0018] Further advantageous developments result from combinations of the features disclosed in the claims, the description and the figures. Short description of the characters

[0019] They show: Fig. 1 is an exploded perspective view of a roller grinder according to the first embodiment, which can be produced using the method according to the invention. Fig. 2 is an exploded perspective view of a roller grinder according to the second embodiment, which can be produced using the method according to the invention. Fig. 3 is a schematic view of the roller grinder according to the first embodiment of the invention in an assembled state. Fig. 4 is a schematic view of the roller grinder according to the second embodiment of the invention in an assembled state. Detailed description of the preferred embodiments

[0020] The preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings. First embodiment (Fig. 1 and 3) - Rollers with integral grinding / polishing surface

[0021] In the first embodiment of the invention, which will be described below with reference to the Figures 1and 3 As described, the roller grinder 1 is constructed from a total of 10 or 12 components and comprises two rollers 2, a handle body 3 (optionally with two bearing sleeves, not shown), two spacer elements 4, an axle 5, two roller bearings 6 (each counting as one component) and two rubber rings 8 arranged on the edge of the rollers 2, which form the running surfaces of the rollers 2.

[0022] Each roller 2 is approximately designed as a cylindrical disc made of stainless steel and comprises a circumferential annular groove in the cylindrical outer surface 2a, in which the rubber ring 8 is held in a form-fitting manner. The thickness or axial length of the roller 2 is, for example, in the range of 2 to 10 mm, in particular approximately 8 mm, while the outer diameter (without rubber ring 8) is, for example, in the range of 40 to 60 mm, in particular 54 mm. The rubber ring 8 preferably has an oval cross-section, the main axis of which is preferably aligned parallel to the outer surface 2a of the roller 2. On the intended end face of each roller 2 there is an integrally formed grinding or polishing surface 1a, 1b. The transition from the circumferential side 2a provided with the annular groove to the end face of the roller 2 is rounded or chamfered, the radius of curvature of the rounding being in the range of 0.5 to 2 mm, in particular approximately 1 mm.The side of the roller 2 intended to face the handle body 3 has a central opening 2b with which the roller 2 is placed onto an axle 5 described below.

[0023] The handle body 3 is a hollow wooden cylinder extending along a central axis X3 and having a cylindrical outer surface 3a, two parallel end faces 3b, and a cylindrical central bore 3c. The central bore 3c of the handle body 3 (see Fig. 3) comprises in one variant two sections with different diameters, namely a central section with a smaller diameter and end sections with larger diameters. On the front side of the central section there are two parallel and outward-facing bearing support sections 3d for the axial support of rolling bearings 6. The position of the rollers 2 relative to the handle body 3 is determined by these bearing support sections 3d. In an alternative variant, the handle body 3 comprises a central bore 3a with a uniform diameter. To fix the rolling bearings 6 described below, a bearing sleeve (not shown) is inserted into the central bore 3a from each end side 3a of the handle body 3, which bearing sleeve is supported by a flange on the end side 3a of the handle body 3 and forms a bearing support section 3d at a base. The base of the bearing sleeve is provided with an opening for the insertion of the axle 5.For particularly high-quality designs, the handle body 3 is manufactured in one piece from oak, walnut, beech, or spruce. The outer diameter of the handle body 3 preferably corresponds to the outer diameter of the roller 2 (without rubber ring 8), so that the outer surface 3a of the handle body 3 and the outer surfaces 2a of the rollers 2 are identical in the intended assembly state (see . Fig. 3 ) merge flush with one another. At the time of manufacture of the handle body 3, the moisture content of the wood should be as low as possible and not exceed 10%. The outer diameter of the handle body 3 is, for example, in the range of 50 to 60 mm and in this case is approximately 54 mm. The axial length of the handle body 3 is, for example, in the range of 55 to 75 mm and in this case is approximately 64 mm.

[0024] The axle 5 is designed as a stepped axle 5 with a central section 5a and stepped bearing sections 5b at the ends.

[0025] The rolling bearing 6 is, for example, a commercially available ball bearing. The inner diameter of the inner ring of the rolling bearing 6 is matched to the outer diameter of the bearing section 5b of the axle 5 and can be arranged thereon, so that the inner ring is supported axially on the central section 5a of the axle 5. The outer diameter and axial length of the rolling bearing 6 are matched to the dimensions of the handle body 3. The rolling bearing 6 can therefore be precisely inserted into the central bore or bearing sleeve of the handle body 3 and can be supported axially with the outer ring on the bearing support section 3d.

[0026] The spacer element 4 is, for example, an annular disc or cylindrical sleeve that can be pushed onto the bearing section 5b of the axle 5 to support itself on the inner ring of the rolling bearing 6 and a roller 2. Various types of spacer elements 4 are provided, each having a different axial length, in order to precisely adjust the distance between the rollers 2 to be attached to the axle 5, depending on the actual dimensions of the handle body 3—and thus the gap between each roller 2 and the handle body 3.

[0027] When assembled, the axis 5 and the associated spacer elements 4, rolling bearings 6 and rollers 2 have a common central or rotational axis X5.

[0028] The roller grinder 1 is assembled from the aforementioned components by placing a roller bearing 6, a spacer element 4, and a roller 2 onto each bearing section 5b of the axle 5 extending through the central bore 3c of the handle body 3, so that the inner ring of the roller bearing 6 rests on the central section 5a of the axle 5, and the spacer element 4 is secured between the inner ring of the roller bearing 6 and the inner side of the roller 2. The roller 2 is then firmly and permanently connected to the axle 5 by press-fitting, resulting in a press fit at the connection points. The outer ring of the roller bearing 6 is secured to the handle body 3 by force-fitting and, if necessary, form-fitting. Second embodiment (Fig. 2 and 4) - Rollers with separate grinding / polishing roller

[0029] In the second embodiment of the invention, which is described below with reference to the Figures 2 and 4As described, the roller grinder 1 comprises essentially the same components and features as the roller grinder 1 of the first exemplary embodiment, with the exception of the following differences: While in the first exemplary embodiment the grinding and polishing surfaces 1a, 1b are formed integrally with the end faces of the rollers 2 and are thus an integral part of the roller grinder 1, the roller grinder 1 according to the second exemplary embodiment of the invention comprises separate grinding and polishing discs 7, on the end faces of which the grinding and polishing surfaces 1a, 1b are formed. The grinding and polishing discs 7 can be detachably connected to the roller 2 or to the axle 5 by screwing integrally formed threaded sockets 7b into corresponding counter threads.In contrast to the first embodiment, the rollers 2 are not chamfered or rounded on the outward-facing end face, so that the outer surfaces 7a of the grinding and polishing wheels 7 merge flush with the outer surface 2a of the adjacent roller 2. Instead, the grinding and polishing wheels 7 are each chamfered or rounded at the transition between the outer surface 7a and the respective grinding or polishing surface 1a, 1b. The radius of curvature on the end face of the grinding or polishing wheel 7 is, for example, in the range of 0.5 mm to 2 mm and is preferably approximately 1 mm. List of reference symbols

[0030] 1Roller grinder 1aGrinding surface 1bPolishing surface 2Roller 2aSide surface or peripheral side 2bOpening 3Handle body 3aSide surface 3bEnd face 3cBore 3dBearing support section 4Spacer element 5Axis 5aCentral section 5bBearing section 6Bearing 7Grinding / polishing disc 7aSide surface 7bThreaded socket 8Rubber ring USubstrate X1Rotation / central axis of roller grinder X3Rotation / central axis of handle body X5Rotation / central axis of axis, bearing, and if applicable, grinding / polishing disc

Claims

1. Method for producing a rolling grinder (1) having at least one grinding or polishing face (1a, 1b) for grinding and / or polishing a cutting tool, wherein the rolling grinder (1) is formed substantially from two rollers (2), a grip body (3) to be arranged between the rollers (2) and rotatably relative thereto, and a shaft (5) to be supported rotatably in the grip body (3), characterized in that, each of the rollers (2) is connected to the shaft (5) in a frictionally engaged manner by press-fitting.

2. Method according to the preceding claim, characterized in that one or both of the rollers (2) is / are connected to the shaft (5) in a frictionally engaged manner by press-fitting only.

3. Method according to one of the preceding claims, characterized in that one or both of the rollers (2) for connection to the shaft (5) has / have a temperature difference to the shaft (5).

4. Method according to one of the preceding claims, characterized in that one or both of the rollers (2) is / are plugged onto the shaft (5) or is / are inserted into the shaft (5).

5. Method according to one of the preceding claims, characterized in that a stepped shaft (5) with a center section (5a) and two end-side stepped support sections (5b) is used as the shaft (5).

6. Method according to the preceding claim, characterized in that a rolling bearing (6) and one of the rollers (2), and optionally a spacer element (4), are arranged on each support section (5b), preferably such that the rolling bearing (6) is axially supported with its inner ring on the center section (5a) of the shaft (5) and / or the spacer element (4) is axially fixed between the rolling bearing (6) and the roller (2).

7. Method according to the preceding claim, characterized in that the rolling bearing (6) is fixed to the grip body (3) by its outer ring in a frictionally engaged and / or form-fit manner.

8. Method according to one of the preceding claims, characterized in that one or both of the rollers (2) has / have a grinding or polishing face (1a, 1b) non-detachably arranged thereon, preferably on the end face, wherein the grinding or polishing face (1a, 1b) is preferably integrally formed with the roller (2) or non-detachably connected thereto, wherein the grinding or polishing face (1a, 1b) is particularly preferably formed as a coating, in particular as a ceramic coating.

9. Method according to one of the preceding claims, characterized in that a grinding or polishing wheel (7) provided with the grinding or polishing face (1a, 1b) is attached to one or both of the rollers (2), preferably detachably.