Brush unit
Patent Information
- Application Number
- JP2023008440
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-01-26
- Filing Date
- 2023-01-24
- Publication Date
- 2026-01-29
AI Technical Summary
Existing brush units produce non-uniform and anisotropic roughness profiles on workpiece surfaces due to fixed bristles and U-shaped bristle configurations, requiring additional manual or mechanical movements to achieve uniformity, which is inefficient and sometimes impossible.
The brush belt and bristle ring are inclined relative to the brush holder axis, forming an acute angle of about 60° to 90°, preferably 70° to 85°, allowing for an oscillating motion that uniformly covers the workpiece surface, and can be helically guided to enhance uniformity.
This design results in a homogeneous roughness profile with uniformly distributed craters, overcoming the anisotropy issues of prior art by ensuring consistent machining without additional manual or mechanical movements.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a brush unit having a brush holder rotatably driven about an axis, and a ring brush substantially composed of a brush belt and bristles connected to the brush belt, forming a bristle ring and protruding outward. Similarly, the object of the present invention is a rotary brush tool provided with such a brush unit, and a method for machining the surface of a workpiece by means of said brush unit.
Background Art
[0002] In the case of a known and common brush unit of the configuration described at the beginning in the European Patent No. 1834733, an approach is made such that the bristles are braked for a predetermined time by means of a stop means that dips into the rotating bristle ring. After the release of the bristles by the passage of the stop means, the kinetic energy accumulated thereby, i.e., by the bristles and / or the brush belt holding the bristles, can be utilized. The kinetic energy is used mainly for the impact machining of the surface of the workpiece by the bristles. Thereby, an effect equivalent to that observed in so-called sandblasting is obtained. The advantage of the known approach described in European Patent No. 1834733 over sandblasting is that the work is done without a blasting material, whereby the equipment-technical costs are significantly reduced accordingly. Environmental pollution by the blasting material can also be avoided. In addition, a particularly inexpensive configuration and an efficient approach are observed. It has been proven effective in itself.
[0003] In another common prior art described in International Publication No. 2012038537, an approach is taken in which a stopping means immersed in a rotating bristle ring is simultaneously formed as an abrasive for the bristle. In this case, the two functions, namely the stopping function and the abrasive function, can be distinguished depending on the rotational direction of the ring brush and / or the adjustment position of the stopping means relative to the bristle ring. Thus, in practice, the stopping means is formed to be adjustable relative to the bristle ring. In this case, the adjustment of the stopping means is performed radially and / or tangentially. Eccentric adjustment of the stopping means is also possible. In addition, the stopping means can be adjusted by the driven bristle.
[0004] Conventional techniques have proven effective in essentially processing the surface of a workpiece with bristle and achieving the resulting roughness. However, with previous approaches, the workpiece surface may not consistently and uniformly have the "craters" induced by bristle. While it is true that a configurable roughness comparable to sandblasting can be achieved, allowing subsequent coating and welding processes on the workpiece surface to proceed without problems, the roughness profile is subject to variation; that is, conventional techniques exhibit a certain degree of anisotropy. However, for many applications, isotropic and uniform roughness on the treated workpiece surface is required.
[0005] The anisotropy or lack of uniformity in the roughness profile observed in prior art is essentially due to the fact that the bristle is typically fixed to a brush belt. Since the bristle is also often formed as a U-shaped bristle, the brush belt supporting the bristle has rows of bristles and axial spacing between them in its circumferential direction, which contribute, for example, to the U-shape of the bristle. The spacing between individual rows of bristle causes the roughness profile to be formed unevenly during impact machining of the workpiece surface. In practice, attempts have certainly been made to address this by having the user move the brush unit or a rotary brush tool equipped with this brush unit back and forth, for example, across the surface.
[0006] Aside from the fact that such movement is cumbersome and does not necessarily contribute to the required uniformity, such an approach cannot be directly implemented, for example, when mechanically processing the surface of a workpiece by a machine, such as a robotic arm. Furthermore, the prior art requires more effective processing of the workpiece surface. Herein, the present invention intends to address this as a whole. [Prior art documents] [Patent Documents]
[0007] [Patent Document 1] European Patent No. 1834733 [Patent Document 2] International Publication No. 2012038537 Brochure [Overview of the Initiative] [Problems that the invention aims to solve]
[0008] The fundamental technical challenge of this invention is to develop such a brush unit so that the resulting roughness profile has increased uniformity on the surface of the processed workpiece compared to conventional techniques. In addition, the possibility of increasing the roughness as needed should also be maintained. [Means for solving the problem]
[0009] To solve this technical problem, the present invention proposes that in a general brush unit within the scope of the present invention, the longitudinal spread of the brush belt, and therefore the bristle ring, is connected to the brush holder such that it is offset from the perpendicular to the axis of the brush holder and extends obliquely to the axis.
[0010] In this regard, the approach is usually such that the longitudinal spread of the brush belt and the axis of the brush holder form an acute angle of approximately 60° to less than 90°. Preferably, in this regard, an acute angle of approximately 70° to 85° is observed. Particularly preferably, in this regard, an acute angle of approximately 85° has been found to be advantageous.
[0011] This "inclination" of the brush belt, and therefore the bristle ring, relative to the axis of the rotationally driven brush holder, provides particularly uniform machining of the workpiece surface. This is because the bristle ring, extending obliquely to the axis of the brush holder, ultimately contributes to the oscillating rotational action on the workpiece surface. The oscillating motion is explained by the fact that the bristle of the bristle ring extends obliquely to the axis of the brush holder. Considering one rotation of the bristle ring, this corresponds to the bristle not tracing one and the same radius relative to the workpiece surface during one rotation of the brush holder, and therefore machining the surface along a somewhat distinct line within the cross-section at one point. Rather, the inclination of the brush belt, and therefore the bristle ring, contributes to the bristle axially covering a predetermined area of the workpiece surface, the so-called machining zone, in the side view of the brush holder, as the brush holder rotates relative to the workpiece fixed to it.
[0012] This back-and-forth motion of the bristle in the side view is interpreted as an oscillating motion within the scope of this application. This is because, assuming the bristle ring is a disc embedded in the brush holder at an angle to the axis of the brush holder, the disc of the bristle ring oscillates in the side or front view relative to the brush holder. This is because the axis of rotation belonging to the disc changes direction when the bristle ring rotates, as will be described in detail below with respect to the embodiments. In any case, the overall effect is an oscillating rotation of the workpiece surface, which contributes particularly to the machining of a uniform surface. In particular, the heterogeneity that may occur in the prior art is not clearly observed.
[0013] In a more advantageous embodiment, the brush belt is guided around the axis of the brush holder more than one rotation and connected to the brush holder. In this case, the design is further made such that the brush belt spirally surrounds the brush holder. Here, generally, the approach is taken such that the brush belt spirally extending with respect to the axis of the brush holder has a constant angle of inclination, and therefore the spiral traced by the brush belt relative to the axis of the belt holder extends regularly. Of course, basically, irregular extension is also conceivable.
[0014] This additional helical formation of the brush belt extension relative to the axis of the brush holder effectively defines, if intended, multiple discs of the bristle ring, which perform an oscillating motion around their virtual axis of rotation. As a result, this causes the individual axial working areas or machining zones set by the oscillating motion and covered by each bristle to overlap with one another. In this case, the result is that the workpiece to be machined thus has a roughness profile on its surface with a homogeneity not previously observed—that is, the individual craters belonging to the roughness profile are uniformly distributed across the surface at almost the same depth and at the same intervals from one another.
[0015] To specifically and individually realize the helical extension of the brush belt relative to the axis of the brush holder, the brush holder specifically has a circumferential groove for housing the brush belt. In this case, the approach is usually such that the brush belt engages with the groove with substantially no lateral play. In this case, the groove is advantageously defined by groove walls. In this case, the groove walls are generally perpendicular to the cylinder surface of the brush holder. In practice, it has been found to be particularly advantageous when the brush holder, including the groove and groove walls, is formed as a plastic molded part, especially as a plastic injection molded part.
[0016] In order to fix the brush belt in the groove, the brush belt is at least pointwise coupled to the brush holder. In this case, the coupling is generally effected mechanically and / or adhesively. As a rule, the brush belt is formed as a fabric belt, for example as a polyamide fabric belt.
[0017] The brush unit described can furthermore and advantageously be provided with at least one stop means which dips into the rotating bristle ring. By means of the stop means, the roughness can be influenced particularly advantageously and positively, as is described in detail in the applicant's European Patent No. 1834733. Basically, such stop means are of course also unnecessary.
[0018] The subject of the invention is also a rotary brush tool as detailed in claim 13 and a method for machining the surface of the workpiece as described in claims 14 and 15.
[0019] Hereinafter, the invention will be explained in more detail with the aid of the drawings which illustrate only one exemplary embodiment.
Brief Description of the Drawings
[0020] [Figure 1] Perspective view of a brush unit and a rotary brush tool according to the invention [Figure 2] Detailed view of a brush holder formed according to the invention [Figure 3] Side view of the brush holder during machining of the surface of the workpiece and the oscillating rotary action provided according to the invention on said surface
Embodiments of the Invention
[0021] FIG. 1 shows a rotary brush tool having a machine housing 1 and a drive unit 2 for a brush unit 3 accommodated in the machine housing, which is only shown schematically. The brush unit 3 has a brush holder 4 which can be rotationally driven about an axis A. The brush holder 4 is the subject of the detailed view in FIG. 2.
[0022] In addition, a ring brush 5, 6 is provided which consists essentially of the brush belt 5 and bristles 6 which are connected to this brush belt, form the bristle ring 7 and project outwards. In particular, in the schematic side view according to FIG. 3, it can be seen how the individual bristles 6 are fixed to the brush belt 5. For this purpose, the individual bristles 6 can be formed in a U-shape and inserted into the respective receiving holes 5a in the brush belt 5. This is shown in detail only in FIG. 3.
[0023] According to the invention, the design is such that the longitudinal extent L of the brush belt 5 shown in FIGS. 2 and 3, and thus also the bristle ring 7, is connected to the brush holder 4 so as to be offset from the axis A of the brush holder 4 in the vertical direction and to extend obliquely with respect to the axis A. In fact, in this embodiment and according to FIGS. 2 and 3, in this connection, an acute angle α is recognized between the longitudinal extent L of one brush belt 5 and the axis A of the other brush holder 4. According to this embodiment, the acute angle α in question is assumed to have a value within the range of about 70° to 85°, but in any case it is less than 90°. Here, generally, an angle α within the range of about 85° is used, but this is of course only exemplary.
[0024] Due to this inclination of the bristles 6 which project outwards from the brush belt 5 with respect to the axis A of the brush belt 5, and thus also of the bristle ring 7 or the brush holder 4, overall, the surface 9 of the workpiece illustrated in FIG. 3 can be subjected to the action of an oscillating rotation. This can be best understood from FIG. 3.
[0025] In other words, assuming that the brush belt 5 and the bristle 6 connected to this brush belt, and therefore the bristle ring 7 as a whole, constitute a disk, the disk in question rotates itself around its own intrinsic axis of rotation R when the brush holder 4 rotates around its axis A in the rotation shown in Figure 3. Due to the rotation of the brush holder 4 and the tilt of the disk, the associated and hypothetical axis of rotation R undergoes a change in the direction shown in Figure 3. Here, ultimately, a precessional or oscillating motion of the hypothetical disk is observed, and this motion is evident from the different orientations of the hypothetical axis of rotation R of the disk.
[0026] The oscillating motion of the ring brushes 5 and 6, and the resulting oscillating rotational action on the surface 9 of the workpiece, result in each bristle 6 not only acting as a point on the surface 9 of the workpiece during its rotation, but rather expanding axially and covering the machining area B on the surface 9 of the workpiece as shown in Figure 3.
[0027] Since the bristle 6 are typically formed in a U-shape and therefore have small gaps between them, the problem surface 9 of the workpiece is no longer actually acted upon in strips by the individual bristle 6 as in the prior art. Rather, the individual machining areas B of the bristle 6 overlap each other, thus contributing to a particularly homogeneous roughness profile of the workpiece surface 9 as a whole. This result and form of roughness profile has not been observed before.
[0028] The brush belt 5 is not guided around the brush holder 4 for only one rotation, but is guided around the axis A of the brush holder 4 for more than one rotation and is connected to the brush holder. In fact, the brush belt 5 spirally surrounds the brush holder 4. In this case, the design as a whole is carried out so that the brush belt 5 extending spirally around the axis A of the brush holder 4 has a constant angle of inclination, that is, ultimately the angle α between the longitudinal extension L of each brush belt 5 and the axis A of the brush holder 4, as individually shown in Figure 2, is designed to be the same size. In other words, the brush belt 4 is guided in a uniform spiral around the axis A.
[0029] Furthermore, in this case, the design is such that the brush belt 4 engages with a groove 10 that extends around it substantially without lateral play, as can be seen from Figure 2. In this case, the groove 10 is defined by groove walls 11 that are upright relative to the cylinder surface. In this case, the brush holder 4, together with the groove 10 and the groove walls 11 defining the groove 10, is formed as a plastic part, preferably as a plastic injection molded part. In this case, the groove 10 and groove walls 11 can be introduced by printing or by a three-dimensional molding process. For example, the groove 10, as well as the groove walls 11, can be mechanically manufactured by milling a cylindrical plastic part.
[0030] The brush belt 5 is connected to the brush holder 4 at least in a point-like manner. In this case, the point-like connection can be mechanical and / or adhesive. In addition, the design is usually such that the brush belt 4 is manufactured as a woven belt, particularly from a polyamide woven fabric. Furthermore, a stopping mechanism 12 may be provided that is immersed in the rotating bristle ring 7 and shown only in Figure 1, which is connected to the arm 13 of the rotating brush tool shown therein or its mechanical housing 1.
[0031] As soon as the brush holder 4 rotates about its axis A, the aforementioned oscillating rotational action is applied to the surface 9 of the workpiece. In addition, each individual bristle 6 or helix of the brush belt 4 on the surface 9 of the workpiece processes the axially expanded processing zone B, as shown in Figure 3. In this way, the individual processing zones B overlap, and the surface 9 acquires a particularly homogeneous roughness profile. In this embodiment, the individual bristle 6 is made from steel. Of course, other materials such as plastic or a combination of materials are also conceivable.
Claims
1. A brush unit (3) having a brush holder (4) rotatably driven about an axis (A) and ring brushes (5, 6) essentially consisting of a brush belt (5) and bristles (6) connected to the brush belt, forming a bristle ring (7) and projecting outward, The brush unit (3) is characterized in that the longitudinal extent (L) of the brush belt (5), and therefore the bristle ring (7), is connected to the brush holder (4) so as to extend obliquely relative to the axis (A) of the brush holder (4) and deviate from the vertical direction relative to the axis (A).
2. 2. The brush unit (3) according to claim 1, characterized in that the longitudinal extent (L) of the brush belt (5) and the axis (A) of the brush holder (4) form an acute angle (α) with each other of approximately 60° to less than 90°, preferably 70° to 85°, particularly preferably approximately 85°.
3. 2. A brush unit (3) according to claim 1, characterized in that the brush belt (5) is guided around the axis (A) of the brush holder (4) for more than one revolution and is connected to said brush holder.
4. 2. A brush unit (3) according to claim 1, characterized in that the brush belt (5) spirally surrounds the brush holder (4).
5. 5. A brush unit (3) according to claim 4, characterized in that the brush belt (5), which extends spirally relative to the axis (A) of the brush holder (4), has a constant inclination angle.
6. 2. A brush unit (3) according to claim 1, characterized in that the brush holder (4) comprises a circumferentially extending groove (10) for receiving the brush belt (5).
7. 7. A brush unit (3) according to claim 6, characterized in that the brush belt (5) engages in the groove (10) substantially without lateral play.
8. 7. A brush unit (3) according to claim 6, characterized in that the grooves (10) are each defined by groove walls (11) upstanding relative to the cylinder surface.
9. 2. The brush unit (3) according to claim 1, characterized in that the brush belt (5) is connected to the brush holder (4) at least at points.
10. 10. Brush unit (3) according to claim 9, characterized in that the connection is mechanical and / or adhesive.
11. 2. The brush unit (3) according to claim 1, characterized in that the brush belt (4) is formed as a textile belt and the brush holder (4) is formed as a plastic molded part.
12. 2. A brush unit (3) according to claim 1, characterized in that additionally there is provided a stop means (12) which sinks into the rotating bristle ring (7).
13. A rotary brush tool having a machine housing (1), a drive unit (2) and a brush unit (3), A rotary brush tool, characterized in that the brush unit (3) is formed according to any one of claims 1 to 12.
14. 13. A method for processing a surface (9) of a workpiece by means of a brush unit (3) according to any one of claims 1 to 12, characterized in that the bristles (7) of the ring brushes (5, 6), which extend obliquely relative to the axis (A) of the brush holder (4), exert an oscillating rotational action on the surface (9).
15. 15. A method according to claim 14, characterized in that the individual working zones (B) generated on the surface (9) by each spiral of the brush belt (5) overlap on the end side.