EP3219439A1 - Grinding wheel - Google Patents

Abstract

Grinding wheel (1) having an abrasive coating (2) and a central base body (3), wherein the abrasive coating (2) is connected to a carrier (4), and in the radial direction (5) between the base body (3) and the carrier ( 4) an adhesive layer (6) is arranged, the grinding wheel (1) having an axis of rotation (11) in one, preferably in each, cross-sectional plane (41) normal to the axis of rotation (11) of the grinding wheel (1) the abrasive coating (2) a first surface (42) and the carrier (4) have a second surface (43) and the ratio of the first surface (42) of the abrasive coating (2) to the second surface (43) of the carrier (4) is greater than 1, and the abrasive coating (2) and the carrier (4) in the region of the connection between the abrasive coating (2) and the carrier (4) penetrate each other.

Description

The invention relates to a grinding wheel with an abrasive coating and a central base body, wherein the abrasive coating is connected to a carrier, and in the radial direction between the base body and the carrier an adhesive layer is arranged. The invention further relates to a method for producing a grinding wheel.

Abrasive wheels with an abrasive coating and a central body are well known in the art. In this case, the connection of the base body with the abrasive coating takes place, for example, in that these two components are hot-pressed together in the course of production.

Such grinding wheels have a number of disadvantages: For certain applications, it is advantageous to use very brittle abrasive coatings. However, these are not produced in the described structure according to the prior art, or if, then only with very low covering thicknesses. The reason for this is that, due to the compound building up between carrier and coating during the hot pressing process and due to different physical properties of carrier and coating as a function of the temperature (expansion coefficients, heat capacities, thermal conductivities, heat penetration and temperature conductivities, density), stresses occur weaker brittle part can cause cracks. Furthermore, the grinding wheels according to the prior art on a very high weight.

The objective technical object of the present invention is thus to provide a comparison with the prior art improved grinding wheel, which overcomes the disadvantages described, and in particular can have very brittle abrasive coatings with large pad thicknesses, while high stability between the abrasive coating and the carrier. A Another object of the invention is to provide a suitable method for producing such a grinding wheel.

These objects are solved by the features of independent claims 1 and 12.

It is therefore provided according to the invention that the grinding wheel has an axis of rotation, in one, preferably in each, cross-sectional plane normal to the axis of rotation of the grinding wheel of the abrasive coating a first surface and the carrier have a second surface and the ratio of the first surface of the abrasive coating to the second surface of the Carrier is greater than 1, and penetrate the abrasive coating and the carrier in the region of the connection between the abrasive coating and the carrier each other.

With this structure, the component of the grinding wheel connected to the abrasive coating can be significantly reduced in its dimensions. In particular, it is possible to carry out the carrier in the grinding wheel according to the invention smaller than the abrasive coating, whereas in the prior art, the base body connected to the abrasive coating and is usually larger than the abrasive coating. If you now connect the abrasive coating with the carrier by a hot pressing process, it comes opposite to the prior art to a reversal of the press force distribution: The majority of the pressing force now rests on the abrasive coating and not as in the prior art on the central body. As a result, the greatly reduced carrier builds less stress on the abrasive pad during hot pressing, thereby reducing the susceptibility of the abrasive pad to cracking. In addition, the reduced carrier, when cooled, causes less stress than a prior art abrasive pad carrier. The reason for this is that the lower mass of the carrier results in less expansion under heat. Overall, this makes it possible to produce more brittle abrasive coatings with larger coating thicknesses. Another advantage of the invention is that, by providing a carrier in addition to the central body of the base body of a lighter compared to the component which carries the abrasive coating, lighter material can be made, resulting in a massive weight reduction.

By the feature that the abrasive coating and the carrier penetrate each other in the region of the connection between the abrasive coating and the carrier, it is to be understood that the material of the abrasive coating and the material of the carrier interpenetrate each other. This results in a so-called hypersurface between the abrasive coating and the carrier.

In the prior art, it is usually provided that first the carrier is constructed, and then the abrasive coating is built up on the carrier. The structure of the combination of abrasive coating and carrier is thus sequential. There is a clear material boundary between the abrasive coating and the carrier.

By creating a hypersurface, a more stable connection can be created compared to the prior art.

According to an advantageous embodiment of the invention, the carrier is connected only via the adhesive layer with the base body.

Furthermore, it can be provided that the adhesive layer forms a first contact surface to the base body and a second contact surface to the carrier, preferably wherein the first contact surface and the second contact surface are aligned substantially parallel to the axis of rotation of the grinding wheel.

It has also proven to be advantageous for the adhesive layer to contact the circumferential surface of the main body and the inner surface of the carrier.

A particularly advantageous embodiment is that the peripheral surface of the base body and the inner surface of the carrier are formed conical, preferably with a cone angle of 3 ° to 5 °. As a result, the adhesive layer can be reduced to less than 0.5 mm, preferably less than 0.2 mm. The conical design leads to a self-centering when joining the parts to be bonded. Finally, this embodiment also has advantages in terms of the running property of the grinding wheel, since imbalances are avoided.

To improve the adhesion of the adhesive layer, it may be provided that the peripheral surface of the base body and / or the inner surface of the carrier has a surface structure, preferably grooves.

Further advantageous embodiments of the grinding wheel are defined in the dependent claims 7-11.

With regard to the method for producing a grinding wheel, it is provided that in a first process step, the abrasive coating is bonded to the carrier, preferably hot pressed, and in a second, subsequent process step, the carrier is bonded to the base body, and in the course of the first process step of Abrasive coating and the carrier are simultaneously constructed and interconnected.

Thus, three processes take place simultaneously: the abrasive coating is formed, the carrier is formed, and the abrasive coating and the carrier are joined together. In the compound of the abrasive coating with the carrier, the material of the abrasive coating and the material of the carrier penetrate each other in the region of the connection between the abrasive coating and the carrier. This results in the hypersurface between the abrasive coating and the carrier.

Methods are known from the prior art, in which first the carrier is constructed, and then the abrasive coating is built up on the carrier. The structure of the combination of abrasive coating and carrier is thus sequential. There is a clear material boundary between the abrasive coating and the carrier.

According to a preferred embodiment of the method, it is provided that a mixture for the abrasive coating, preferably made of a superabrasive and a binder, and / or a mixture for the carrier is provided before the first process step in a preparatory process step, and the
Mixture or the mixtures are molded in one or more dies.

Furthermore, it can be provided that, between the first method step and the second method step, in an intermediate step, the compound of carrier and abrasive coating is shaped and deburred, cleaned and / or sand blasted from the or the press molds.

It has proved to be advantageous that in the course of the second process step for preparing the bond, the connection of carrier and abrasive coating is positioned relative to the base body by at least one spacer, preferably wherein the at least one spacer is formed on the base body, and / or for the process the positioning between the connection of carrier and abrasive coating and the body is temporarily placed.

If the at least one spacer is formed on the main body, then it makes sense that the at least one spacer is designed as an annular thin web which protrudes from the main body.

In the event that at least one spacer is temporarily placed for the process of positioning between the connection of carrier and abrasive coating and the base body, it is for example, three spacers in the form of platelets or the like offset by 120 ° relative to each other to the lay on the inner surface of the carrier and then introduce the body concentric. Subsequently, the platelets are then removed again. In support of the support can be placed on a pad with an adhesive coating, preferably in the form of an adhesive tape, to avoid slippage.

Finally, it has proven to be advantageous that in a final process step after the second process step, a finishing of the grinding wheel is performed, preferably in the course
the finishing at least one formed on the base spacer is removed.

Further details and advantages of the present invention will be explained in more detail below with reference to the description of the figures with reference to the drawings.

Fig. 1

eine erfindungsgemäße Schleifscheibe gemäß einer bevorzugten Ausführungsform in einer Draufsicht,

Fig. 2a

einen Querschnitt der Schleifscheibe gemäß Fig.1,

Fig. 2b

einen Querschnitt einer erfindungsgemäßen Schleifscheibe gemäß einem weiteren Ausführungsbeispiel,

Fig. 3

ein Flussdiagramm zur Illustration einer vorteilhaften Ausführungsform des erfindungsgemäßen Verfahrens zur Herstellung einer Schleifscheibe,

Fig. 4a/4b

in einer Querschnittsdarstellung Formteile zur Herstellung der Verbindung aus Träger und Schleifbelag, und

Fig. 5a/ 5b

eine Hälfte einer Schleifscheibe im Querschnitt zur Illustration zweier Verfahrensstadien beim erfindungsgemäßen Herstellungsverfahren gemäß bevorzugten Ausführungsformen.

Show in it

Fig. 1

a grinding wheel according to the invention according to a preferred embodiment in a plan view,

Fig. 2a

a cross section of the grinding wheel according to Fig.1 .

Fig. 2b

a cross section of a grinding wheel according to the invention according to a further embodiment,

Fig. 3

a flow chart illustrating an advantageous embodiment of the method according to the invention for producing a grinding wheel,

Fig. 4a / 4b

in a cross-sectional representation moldings for producing the compound of carrier and abrasive coating, and

Fig. 5a / 5b

a half of a grinding wheel in cross-section to illustrate two stages of the method in the manufacturing method according to the invention according to preferred embodiments.

FIG. 1 shows a grinding wheel 1 with an abrasive coating 2 and a central base body 3, wherein the abrasive coating 2 is connected to a support 4, and in the radial direction 5 (see, for example FIG. 2a ) between the base body 3 and the carrier 4, an adhesive layer 6 is arranged. The abovementioned constituents of the grinding wheel 1 are substantially rotationally symmetrical and annular.

The central base body 3 has a central bore 7 for mounting the grinding wheel 1 on a drive. Through the central bore 7, a rotation axis 11 of the grinding wheel 1 runs. The rotation axis 11 is oriented substantially normal to the grinding wheel 1. The passage point of the rotation axis 11 of the grinding wheel 1 in the drawing plane according to FIG. 1 is provided with the reference numeral 8.

The central base body 3 is made of aluminum in the illustrated embodiment.

The carrier 4 is pressed together with the abrasive coating 2.

In the in FIG. 1 visible cross-sectional plane of the grinding wheel 1 normal to the axis of rotation 11, the abrasive coating 2 has a first surface 42 and the carrier 4 has a second surface 43 and the ratio of the first surface 42 of the abrasive coating 2 to the second surface 43 of the carrier 4 is greater than one.

• Von außen nach innen umfasst die Schleifscheibe 1 zunächst einen ringförmigen Schleifbelag 2. Die umfangsseitige Fläche 36 des Schleifbelags 2 ist im dargestellten Fall abgeschrägt. Es sind hier aber auch alle anderen üblicherweise verwendeten Geometrien möglich, wie z.B. eine im Wesentlichen parallel zur Rotationsachse 11 ausgerichtete Fläche. Die mittlere Stärke 16 des Schleifbelags 2 in radialer Richtung 5 beträgt im dargestellten Fall ca. 15 mm.

FIG. 2a shows a cross-sectional view of the grinding wheel 1 according to the FIG. 1 along a cross-sectional plane 34 parallel to the axis of rotation 11. From this cross-sectional representation follows:

• From outside to inside, the grinding wheel 1 initially comprises an annular abrasive coating 2. The circumferential surface 36 of the abrasive coating 2 is chamfered in the illustrated case. However, all other commonly used geometries are also possible here, such as a surface oriented substantially parallel to the axis of rotation 11. The average thickness 16 of the abrasive covering 2 in the radial direction 5 is approximately 15 mm in the illustrated case.

To the abrasive coating 2, a carrier 4 connects. The average thickness 17 of the carrier 4 in the radial direction 5 is about 5 mm.

In this case, the abrasive coating 2 in each cross-sectional plane normal to the rotation axis 11 has a first surface 42 and the carrier 4 has a second surface 43, and the ratio of the first surface 42 of the abrasive coating 2 to the second surface 43 of the carrier 4 is greater than one. As an example, one of these cross-sectional planes is shown in dashed lines and provided with the reference numeral 41.

In the region of the connection between the abrasive coating 2 and the carrier 4, the abrasive coating 2 and the carrier 4 form a contact zone 44. Schematically, an enlargement of this contact zone 44 in the FIG. 2a (and analogously in the FIG. 2b ): The material of the abrasive pad 2 and the carrier 4 penetrate each other. This can be determined by the fact that the abrasive coating 2 extends into the area of the carrier 4 with respect to an imaginary material boundary 47, and vice versa. In the material of the abrasive covering 2 are material inclusions 46 of the carrier 4. Conversely, are found in the material of the carrier 4 material inclusions 45 of the abrasive coating 2. Overall, in the region of the connection between the Abrasive coating 2 and the carrier 4 before a hypersurface. By this hypersurface an extremely stable connection between the abrasive coating 2 and the carrier 4 is created.

The carrier 4 is followed by an adhesive layer 6. The average thickness 18 of the adhesive layer 6 in the radial direction 5 is about 2 mm. The adhesive layer 6 forms a first contact surface 9 to the main body 3 and a second contact surface 10 to the carrier 4, wherein the first contact surface 9 and the second contact surface 10 are aligned substantially parallel to the axis of rotation 11 of the grinding wheel 1. Furthermore, it can be seen that the carrier 4 is connected only to the base body 3 via the adhesive layer 6. In addition, the adhesive layer 6 contacts the circumferential surface 12 of the main body 3 and the inner surface 13 of the carrier 4th

And finally, the grinding wheel 1 comprises a central base body 3. The base body 3 has a bore 7, via which the grinding wheel 1 can be mounted on a drive, for example on a motor spindle or the like.

FIG. 2b shows an alternative embodiment of the grinding wheel 1, also in a cross-sectional view. The main difference to that in the FIG. 2a embodiment shown is that the peripheral surface 12 of the base body 3 and the inner surface 13 of the support 4 are formed cone-shaped. The cone angle 14 and 15 is in both cases 3 ° to 5 °, measured relative to an axis parallel to the axis of rotation 11 of the grinding wheel 1. The base body 3 tapers in cross section from the bottom of the grinding wheel 1, starting in the direction of the top of the Schleibeibe, whereas the carrier 4 tapers in the reverse direction, or vice versa. In cross section, the peripheral surface 12 of the base body 3 and the inner surface 13 of the carrier 4 are parallel to each other. This embodiment has - as already stated - several advantages. In particular, the adhesive layer 6 can be minimized. in the In the case shown (it is not a true-to-scale representation), the adhesive layer 6 has a mean thickness 19 of less than 0.2 mm. In addition, the relative orientation of the carrier 4 and the base body 3 is facilitated by this conical embodiment to each other.

FIG. 3 1 shows a flowchart of a preferred embodiment of the method 20 according to the invention for producing a grinding wheel 1. In a first method step 21, the abrasive coating 2 is connected to the carrier 4, more specifically hot pressed, and in a second, subsequent method step 22, the carrier 4 glued to the base body 3. In addition, in the course of the first process step, the abrasive coating 2 under carrier 4 are simultaneously constructed and connected to each other.

Before the first method step 21, a mixture for the abrasive coating 2 made of a superabrasive and a binder and a mixture for the carrier 4 are provided in a preparatory method step 23. The mixtures are molded into one or more dies.

Between the first method step 21 and the second method step 22, the compound of carrier 4 and abrasive coating 2 is formed, deburred, cleaned and sandblasted in an intermediate step 31 from the or the press molds.

In the course of the second method step 22, in order to prepare the bond, the connection between carrier 4 and abrasive coating 2 is positioned relative to the base body 3 by at least one spacer, wherein the at least one spacer is formed on the base body 3. Alternatively or additionally, at least one spacer can be temporarily placed for the process of positioning between the connection between carrier 4 and abrasive coating 2 and the base body 3. An example of an am Base 3 trained spacer 32 is based on the FIG. 5a described in more detail.

In a concluding method step 33, a finishing of the grinding wheel 1 is carried out after the second method step 22, wherein a spacer 32 formed on the main body 3 can be removed during the finishing process (cf. FIG. 5b )

• Nachdem eine Mischung für den Schleifbelag aus einem Superschleifmittel und einem Bindemittel und eine Mischung für den Träger bereit gestellt wurden, wird eine Kombination aus mehreren ringförmigen Pressformen gebildet, nämlich aus einem äußeren Pressring 24, einem Unterstempel 26 für den Schleifbelag und einem Innenteil 25. Hierdurch ergibt sich eine ringförmige Kavität 38, in welche die Mischung für den Schleifbelag eingefüllt wird.

The preparation of the first method step 21 can, as in the FIGS. 4a and 4b represented, wherein the FIGS. 4a and 4b Cross-sectional views of rotationally symmetrical bodies include:

• After a mixture for the abrasive coating of a superabrasive and a binder and a mixture for the carrier have been provided, a combination of a plurality of annular dies is formed, namely an outer pressing ring 24, an abrasive pad lower die 26 and an inner part 25 results in an annular cavity 38, in which the mixture is filled for the abrasive coating.

After filling the coating mixture, an upper punch 27 is placed on the abrasive coating and preconsolidated the abrasive coating mixture by means of a press. The inner part 25 is formed. Advantageously, the upper punch 27 still remains in its position.

As in FIG. 4b shown, a lower punch 28 for the carrier and an inner part 29 are introduced for the carrier in the press ring 24 subsequently. Subsequently, the mixture for the carrier is formed in the annular groove 39, an upper punch 30 placed on the carrier and the carrier mixture by means of a press, such as a hand lever press, pre-compressed.

The filled mold combination formed from molds 24, 26, 27, 28, 29 and 30 is placed under the hot press and the hot pressing operation is performed.

As already stated, in the course of the second method step 22 for preparing the bond, the connection between carrier 4 and abrasive coating 2 can be positioned relative to the base body by at least one spacer. It lends itself to form the base body 3 such that it has a radially projecting spacer ring 32 with a thickness 35 of, for example
0.5 mm. The length 37 of this spacer ring 32 corresponds exactly to the average thickness 18 of the adhesive layer 6 (see FIG. 2a ).

After positioning the connection between carrier 4 and abrasive coating 2 and the base body 3 relative to one another, the process step 22 of the bonding can take place. In this case, adhesive is introduced into the annular cavity 40, preferably injected. Depending on the adhesive and ambient temperature, the adhesive then has to cure for a certain time.

After bonding, a finishing of the grinding wheel can be done. In the event that the connection of carrier 4 and abrasive coating 2 and the base body 3 via at least one spacer 32 which is formed on the base body 3, is positioned (see FIG. 5a ), it makes sense that in the course of finishing this spacer 32 is removed, preferably together with adjacent areas of the base body 3 and the carrier 4. In this way, the abrasive coating 2 is released slightly. FIG. 5b shows the result of this finishing.

In addition, in the course of the finishing process, further processing steps such as, for example, providing the grinding wheel with a label or the like can take place.

In particular, in the event that the average thickness of the adhesive layer 6 is very small, for example less than 0.5 mm, preferably less than 0.2 mm, the bonding can also take place in that the peripheral surface 12 of the base body 3 and / or the inner surface 13 of the carrier 4 is already precoated with an adhesive, and only then the carrier 4 and the base 3 are positioned relative to each other.

Claims (16)

Grinding wheel (1) having an abrasive coating (2) and a central base body (3), wherein the abrasive coating (2) is connected to a carrier (4), and in the radial direction (5) between the base body (3) and the carrier ( 4) an adhesive layer (6) is arranged, characterized in that the grinding wheel (1) has an axis of rotation (11) in one, preferably in each, cross-sectional plane (41) normal to the axis of rotation (11) of the grinding wheel (1) the abrasive coating (2) a first surface (42) and the carrier (4) have a second surface (43) and the ratio of the first surface (42) of the abrasive coating (2) to the second surface (43) of the carrier (4) greater than 1 is, and the abrasive coating (2) and the support (4) in the region of the connection between the abrasive coating (2) and the support (4) penetrate each other. Grinding wheel (1) according to claim 1, wherein the carrier (4) is connected to the base body (3) only via the adhesive layer (6). Grinding wheel (1) according to claim 1 or 2, wherein the adhesive layer (6) forms a first contact surface (9) to the base body (3) and a second contact surface (10) to the carrier (4), preferably wherein the first contact surface (9) and the second contact surface (10) are aligned substantially parallel to the axis of rotation (11) of the grinding wheel (1). Grinding wheel (1) according to one of claims 1 to 3, wherein the adhesive layer (6) the peripheral surface (12) of the base body (3) and the inner surface (13) of the carrier (4) contacted. Grinding wheel (1) according to one of claims 1 to 4, wherein the peripheral surface (12) of the base body (3) and the inner surface (13) of the carrier (4) are cone-shaped, preferably with a cone angle (14, 15) of 3 ° to 5 °. Grinding wheel (1) according to one of claims 1 to 5, wherein the peripheral surface (12) of the base body (3) and / or the inner surface (13) of the carrier (4) have a surface structure, preferably grooves, for improving the adhesion of the adhesive layer ( 6). A grinding wheel (1) according to any one of claims 1 to 6, wherein - The abrasive coating (2) has a superabrasive, and / or a bond made of metal, plastic, ceramic or a combination thereof, and / or - The adhesive layer (6) is formed of a curable adhesive, and / or - The base body (3) made of aluminum, iron material, bakelite aluminum, bakelite graphite, glass fiber reinforced plastic or carbon fiber reinforced plastic is formed. Grinding wheel (1) according to one of claims 1 to 7, wherein the abrasive coating (2) in the radial direction (5) has a mean thickness (16) and the carrier (4) in the radial direction (5) an average thickness (17), and the average thickness (16) of the abrasive pad (2) is greater than the average thickness (17) of the carrier (4). A grinding wheel (1) according to any one of claims 1 to 8, wherein - The abrasive coating (2) in the radial direction (5) has an average thickness (16) of 4 mm to 40 mm, preferably of 10 mm, and / or - The support (4) in the radial direction (5) has a mean thickness (17) of 2 mm to 8mm, preferably of 5 mm, and / or - The adhesive layer (6) in the radial direction (5) has an average thickness (18) of 1 mm to 3 mm, preferably of 2 mm, or a average thickness (19) of less than 0.5 mm, preferably less than 0.2 mm. Grinding wheel (1) according to one of claims 1 to 9, wherein the carrier (4) and the abrasive coating (2) via a substantially parallel or obliquely to the rotation axis (11) aligned contact zone (44) communicate with each other. Grinding wheel (1) according to one of claims 1 to 10, wherein in the base body (3) has a central bore (7) for mounting the grinding wheel (1) is formed on a drive. Method (20) for producing a grinding wheel (1) according to one of claims 1 to 11, wherein in a first method step (21) the abrasive coating (2) is connected to the carrier (4), preferably hot pressed, and in a second , subsequent method step (22) of the carrier (4) is glued to the base body (3), and wherein in the course of the first method step, the abrasive coating (2) and the carrier (4) are simultaneously constructed and interconnected. Method (20) according to claim 12, wherein prior to the first method step (21) in a preparatory method step (23) a mixture for the abrasive coating (2), preferably a superabrasive and a binder, and / or a mixture for the carrier (4 ), and the mixture or mixtures are molded into one or more dies (24, 25, 26, 28, 29). Method (20) according to claim 12 or 13, wherein between the first method step (21) and the second method step (22) in an intermediate step (31) the connection between carrier (4) and abrasive coating (2). from the or the molds (24, 26, 27, 28, 29, 30) formed and deburred, cleaned and / or sand blasted. Method (20) according to any one of claims 12 to 14, wherein in the course of the second method step (22) for preparing the bond, the connection between carrier (4) and abrasive coating (2) relative to the base body (3) by at least one spacer (32). Preferably, wherein the at least one spacer (32) is formed on the base body (3), and / or temporarily placed for the process of positioning between the connection of carrier (4) and abrasive coating (2) and the base body (3) , Method (20) according to one of claims 12 to 15, wherein in a final method step (33) after the second method step (22) a finishing of the grinding wheel (1) is carried out, preferably wherein in the course of finishing at least one of the main body (3) trained spacer (32) is removed.

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