Technical field of the invention

The present invention relates to a method and machine for a refacing brake disc, and more specifically for refacing floating brake discs, for example motor cycle brake discs.

Background

One of the most important parts on a vehicle, such as a motorcycle, is the brakes. A floating brake disc comprises a brake rotor which is arranged floatingly to a brake hub by means of rivets. After a certain amount of usage of a vehicle, the brake rotor get worn and consequently the braking effect decreases and undesired vibrations can appear due to irregularities on the two opposing brake surfaces of the brake rotor.

One way of overcoming the problem with decreased braking effect and undesired vibrations is to exchange the brake rotor to a new brake rotor, however that is costly solution.

Another solution is to reface the braking rotor by abrading or turning the surfaces in a lathe so that irregularities on the brake rotor are reduced, which is known from e.g. US 5, 152, 104. However, present machines and methods are not able to reduce the irregularities to a desired level, but still leave some decreased braking effect and vibrations.

Thus, there is a need for a method and machine for refacing a brake rotor so that it does not suffer from decreased braking effect and/or vibrations.

Summary of the invention

In view of the above mentioned and other drawbacks, the object of the present inventive concept is to provide an improved method and machine for refacing floating brake discs. A particular object is to provide a method and a machine that can be used to restore a brake disc so as to alleviate the decrease in braking effect and/or the increase in vibrations.

The invention is based on the inventor's realization that irregularities in the form of thickness variations of the rotor at the same radial distance from the center of the disc cause the vibrations and decreased brake effect. Further, the inventor has realized that by rotating the brake rotor and simultaneously abrading the two surfaces of the rotor with two abrading members moving in an oscillating movement, irregularities in the form of thickness variations of the rotor can be reduced to a level where the brake disc does not, or almost not, suffer from decreased braking effect and vibrations.

According to a first aspect of the inventive concept, above and other objects are achieved through a method of refacing a floating brake disc comprising the steps of rotating a brake rotor, while rotating the brake rotor, pressing a first abrading member towards a first surface of the brake rotor and simultaneously pressing a second abrading member towards a second opposite surface of the brake rotor, and during said pressing, moving said first and second abrading members in an oscillating movement having a radial component relative to the brake rotor.

In the context of the application an "abrading member" should be understood as any type of member which can have a grinding and/or polishing effect on the brake rotor. In one embodiment such a member is a caliper with a grinding effect.

Moreover, "oscillating movement" should be understood as any movement which has at least two end positions and moves between the at least two end positions.

Also, a "floating brake disc" should in the context of the application be understood as a brake disc comprising a brake rotor which is arranged floatingly to a brake hub by fastening means. Fastening means can be rivets, bolts or equivalents. In one embodiment a resilient washer is arranged between said fastening means and said brake hub so that the axial distance between the brake hub and the brake rotor can be altered depending on the washers' compression.

By simultaneously refacing two opposing surfaces of the brake rotor, the two opposing abrading members exert opposing forces on the floating brake rotor, and thereby the brake rotor can be kept in substantially the same axial position in spite of the fact that the brake rotor is resilient connected to the brake hub through resilient rivets.

Moreover, by moving the abrading members in an oscillating movement the irregularities on the surfaces of the brake rotor can be reduced to a level where the brake disc does not suffer from decreased braking effect and vibrations. The fact that the oscillating movement comprises a radial component enables every abrading portion of the abrading member to abrade different portions of the brake rotor surface, which prevents undesired grooves and also contributes to reduce existing irregularities.

Moreover, when the brake rotor surfaces are abraded according to the method above, contaminations from the brake linings are removed and thereby the brake effect is improved.

According to another embodiment of the inventive concept, not only said rotated brake rotor is rotated but the whole brake disc comprising a brake rotor coupled to a brake hub by fastening means is rotated.

According to another embodiment of the inventive concept, the method further comprises the step of providing a first groove on a radially inner portion of said first surface of the brake rotor and a second groove on a corresponding radially inner portion of said opposite second surface of the brake rotor, so that said grooves form a radially inner limit for said abrading members' oscillating movement.

One of the contributing factors to why state of the art refacing methods for floating brake discs does not show a satisfying result can be overcome through providing the grooves on said brake rotor surfaces. In state of the art methods the brake rotors become frustoconical due to the fact that the innermost portion of the refaced surface obtains a radius projection. The projection will force the abrading member to reface the surface with an angle so that the brake rotor will obtain a thickness which tapers radially outwardly.

By providing said groove the brake rotor will not obtain a projection at the radially inner portion, thus the brake rotor can be refaced with two parallel surfaces.

According to yet another embodiment of the inventive concept, said grooves are about 0.1 mm to about 1 .0 mm deep.

Thereby, the depth of the groove exceeds the depth of material potentially abraded from the brake rotor during the refacing method, but does not affect the structural strength of the brake rotor.

According to another embodiment of the inventive concept, at least one of said grooves measures about 0.5 mm to about 5 mm between an inner radial edge and an outer radial edge of said groove. According to yet another embodiment of the inventive concept, at least one of said grooves measures about 2 mm to about 3 mm between an inner radial edge and an outer radial edge of said groove.

Thereby, the width of the groove is sufficiently wide to constitute a radially inner limit for said abrading members' oscillating movement and at the same time the amount of removed material is limited.

According to yet another embodiment of the inventive concept, the radially inner lim it for said abrading members' oscillating movement is disposed between said grooves' said inner and outer radial edge.

Thereby, the problem with brake rotors with frustoconical cross- sections due to the abrading method is overcome, since no axial protrusion will appear on the portion between the abraded portion and the non-abraded portion, enabling two parallel abraded surfaces of the brake rotor.

According to yet another embodiment of the inventive concept, the method further comprises the steps of measuring the brake hub for irregularities, and decreasing said irregularities of said brake hub through molding at least a portion of said brake hub by applying a force having a component in a direction orthogonal to said first or second surface.

Thereby, the amount of material abraded from the brake rotor can be limited through first decreasing the irregularities through pushing, pulling or bending selected portions of the brake hub so that some irregularities do not to be abraded. Thereby, both required time for the method and abraded material can be decreased.

According to yet another embodiment of the inventive concept, the method further comprises the steps of measuring said brake rotor for irregularities, and decreasing said irregularities of said brake rotor through molding at least a portion of said brake rotor by applying a force having a component in a direction orthogonal to said first or second surface.

Analogous to above, by pushing, pulling or bending selected potions of the brake rotor some irregularities in the brake rotor can be decreased and thereby both required time for the method and abraded material can be decreased.

According to yet another embodiment of the inventive concept, said rotating of said brake rotor is carried out with a speed of 500-1500 rpm, preferably 900-1200 rpm.

Thereby, the rotation speed of the brake rotor corresponds to the rotation speed which the brake rotor will have during use on a motor vehicle, such as a motor cycle.

According to yet another embodiment of the inventive concept, the method further comprises the initial steps preceding above-mentioned steps of applying degreasing on at least two rivets holding the brake rotor to the brake hub, and rotating said at least two rivets to remove dirt.

The most common reason to why axial movement between the brake hub and the brake rotor is prohibited is that dirt obstructs the resilient function of the springing washer. By applying degreasing, e.g. through lowering the whole brake disc into a degreasing substance and then rotating said rivets, the dirt will be rotated out and the springing effect will be restored. By restoring the springing effect the refacing of the brake disc will have improved results compared to when the springing effect is different for different portions along the perimeter of the brake hub.

According to yet another embodiment of the inventive concept, the method further comprises the step of removing waste material from the air holes in the brake rotor.

When the brake rotor is abraded, grinding waste gathers in the air holes of the brake rotor. To prevent the grinding waste from affecting the refacing results the waste assemblies can be removed from the air holes in the brake rotor. In one embodiment of the inventive concept, this is done through means of blowing compressed air on the air holes, so that the compressed air pushes out the grinding waste from the air holes.

According to yet another embodiment of the inventive concept, the oscillating movement of said first and second abrading members oscillates between an outer end position and an inner end position.

According a second aspect of the inventive concept above and other objects are achieved through a machine for refacing floating brake discs according to the method as described above, comprising rotating means for rotating a brake rotor, at least two abrading members adapted for simultaneously refacing a first surface and a second surface of a brake rotor, and oscillating means for oscillating said abrading members so that the oscillating movement direction has a radial component.

The benefits of this aspect of the invention are analogous to the benefits described above.

By providing a machine as described above, two opposing surfaces of the brake rotor can simultaneously be refaced by the two opposing abrading members exerting opposing forces on the floating brake rotor. Thereby, the brake rotor can be kept in substantially the same axial position in spite of the fact that the brake rotor is resiliently connected to the brake hub through spring washers arranged in abutment to the rivets holding the brake rotor to the brake hub.

Moreover, by providing an oscillating means for oscillating the abrading members in a movement with radial component, the irregularities on the surfaces of the brake rotor can be reduced to a level where the brake disc does not suffer from decreased braking effect and vibrations.

According to one embodiment of the inventive concept, the machine for refacing brake discs according to the method as described above, comprises a rotator arranged to rotate a brake rotor, two abrading members adapted for simultaneously refacing a first surface and a second surface of a brake rotor, and an radial oscillator for oscillating said abrading members so that the oscillating movement direction has a radial component.

According to one embodiment of the inventive concept, the rotator is a motor coupled to a driving shaft and a chuck for receiving a brake hub.

According to yet another embodiment of the inventive concept, the machine further comprises grinding or cutting means for providing a groove on a radially inner portion of the first surface of the brake rotor and a second groove on the opposite second surface of the brake rotor.

In one embodiment of the inventive concept the grinding or cutting means for providing said grooves comprises a first grinding disc for abrading the first groove and a second grinding disc for abrading the second groove. In yet another embodiment of the inventive concept, the grinding discs are adjustable in the brake rotor's axial direction for controlling the depth of the grooves provided by the grinding discs. According to yet another embodiment of the inventive concept, the grinding discs are adjustable in a radial direction, for adjusting at what radial distance from the center of the brake rotor the groove shall be provided.

By having two grinding discs to provide both said first and second grooves can be accomplished at the same radial distance from the center of the brake rotor without altering the radial position of the grinding discs after the first groove is provided and before the second groove is provided.

In another embodiment of the inventive concept the grinding or cutting means for providing said grooves comprises a first cutting tool for turning the first groove and a second cutting tool for turning the second groove. According to yet another embodiment of the inventive concept, the machine further comprises a grinding member for providing a groove on a radially inner portion of the first surface of the brake rotor and a second groove on the opposite second surface of the brake rotor.

By providing the above mentioned two grooves the brake rotor can be evenly refaced over the whole surface without any projections at the radially inner portion as have been the case in prior art, thus the brake rotor can be refaced with two parallel surfaces, as discussed above.

According to yet another embodiment of the inventive concept, the machine further comprises abrading member position adjusting means arranged for adjusting a position of at least one of said abrading members in relation to said brake rotor.

According to another embodiment of the inventive concept, the machine further comprises a position adjusting member arranged in abutment to said abrading members so that the position of said abrading members in relation to said brake rotor can be adjusted.

Thereby, the abrading members can be adjusted to abrade any brake disc mounted in the machine for refacing, irrespective of the brake disc size. Moreover, the abrading members are moveable in an axial direction which is beneficial compared to a static arrangement for alleviating irregularities in the brake rotor surfaces.

According to yet another embodiment of the inventive concept, the machine further comprises biasing means for resiliently biasing at least one of said abrading members radially towards the brake rotor.

According to another embodiment of the inventive concept, the machine further comprises a second support with a spring arrangement mechanically arranged proximate to said abrading members, so that said abrading members are resilient in a radial direction.

Thereby, the abrading members are moveable in a radial direction which also is beneficial compared to a static arrangement for alleviating irregularities in the brake rotor surfaces.

According to yet another embodiment of the inventive concept, the machine further comprises abrading member pressure adjusting means arranged for adjusting a pressure at least one said abrading members exerts on said brake rotor.

According to yet another embodiment of the inventive concept, the machine further comprises adjusting members arranged proximate to the abrading members so the pressure exerted by said abrading members on said brake rotor can be adjusted.

By controlling the at least two adjusting members the machine can be controlled so that the brake rotor obtains two parallel surfaces and so that irregularities are decreased to a desired level.

According to yet another embodiment of the inventive concept, said abrading member position adjusting means allows at least one of a vertical adjustment, radial adjustment and an axial adjustment of at least one of said abrading members.

According to yet another embodiment of the inventive concept, said position adjusting member allows vertical adjustments, radial adjustments and axial adjustments of said abrading members.

Thereby, the position of the abrading members can be adjusted in directions with a vertical-, radial- and/or axial component to abrade any brake disc mounted in the machine for refacing, irrespective of the brake disc size.

Brief description of drawings

Above mentioned and other aspects of the inventive concept will be discussed in detail from the support of drawings, wherein:

fig. 1 is a flow-chart illustrating the method according to one embodiment of the inventive concept;

fig. 2 is a flow-chart illustrating the method according to another embodiment of the inventive concept;

fig. 3 is a flow-chart illustrating the method according to yet another embodiment of the inventive concept;

fig. 4 is a flow-chart illustrating the method according to yet another embodiment of the inventive concept;

fig. 5 is a perspective view of a brake disc and a machine according to one embodiment of the inventive concept;

fig. 6 is a perspective view of a brake disc and two abrading members according to one embodiment of the inventive concept;

fig. 7 is a cross-sectional view in the horizontal plane of a brake disc and two abrading members according to one embodiment of the inventive concept;

fig. 8 is an exploded view of two abrading members according to one embodiment of the inventive concept;

fig. 9 is a side view of a brake disc and two abrading members in an inner end position according to one embodiment of the inventive concept; fig. 10 is a side view of a brake disc and two abrading members in an outer end position according to one embodiment of the inventive concept;

Description

In the following description, the inventive concept is described in a system of coordinates with an x-axis called axial axis, a y-axis called a radial axis and a z-axis called a vertical axis. Said x-axis is parallel to the brake rotor's axial direction, said y-axis is parallel to a horizontal direction of the brake rotor's radial axis and said z-axis is parallel to a vertical direction of the brake rotor's radial axis.

In fig. 1 the method 100 according to one embodiment of the inventive concept is illustrated in a flow chart. The method 100 consists of three main steps, wherein the first step 107 is to rotate the brake disc. The main reason to rotate the brake disc 502 is to obtain a relative movement between the brake rotor 503 surfaces and two abrading members 505a, 505b. In theory it would be possible to obtain the relative movement by moving the abrading members 505a, 505b in a corresponding speed, but since the geometry of the brake disc 502 is suitable for rotation it is a superior alternative compared to moving the abrading member. Furthermore, by rotating the brake disc 502 the usage of the brake disc 502 can be simulated, as the brake disc 502 will rotate when in use on a vehicle. In one embodiment the brake disc 502 is rotated by a speed of 500-1500 rpm, preferably 700- 1000 rpm. Thereby, the rotation speed corresponds to regular usage of the brake disc, since 500 rpm corresponds to about 50-60 km/h and 1500 rpm consequently to about 150-180 km/h, depending on the size of the tires.

The second step 109 is pressing a first abrading member 505a towards a first surface 710a of the brake rotor 503 and simultaneously pressing a second abrading member 505b towards a second opposite surface 710b of the brake rotor. By pressing the two abrading members 505a, 505b towards two opposing parallel surfaces of the brake rotor, the axial force exerted from the first abrading member 505a may be received by the second abrading member 505b and vice verse. Thereby, the floating brake rotor 503, which is movable in an axial direction relative the brake hub 506, will be kept in substantially the same radial position relative the brake hub 506 during the refacing method 100. In one embodiment, the abrading member is a grinding member that removes material from the brake rotors' surface. In another embodiment the abrading member has a merely polishing effect, to improve the surface roughness of the brake rotor 503.

The third step 1 10 is moving the first and second abrading members 505a, 505b in an oscillating movement, wherein said movement has a radial direction component. This can be in through several ways, in one embodiment there is a separate oscillator 509 and drive 514 coupled to the abrading members 505a, 505b so they move in an oscillating movement.

By moving the abrading members 505a, 505b with a movement that has a radial component, undesired grooves generated from irregularities in the abrading members 505a, 505b can be avoided.

In one embodiment, as shown in fig. 2, the method comprises a step

208 before abovementioned second step 109. That step is providing a first groove 508a and a second groove on a radially inner portion of said first surface 710a and second surface 710b, respectively. The grooves 508a, 508b can then constitute a radially inner limit for the abrading members' oscillating movement.

In one embodiment of the inventive concept the step of providing said first 508a and second 508b groove is achieved by a first grinding disc 531 a for grinding the first groove and a second grinding disc 531 b for grinding the second groove. In a further embodiment, the first groove is achieved by, while rotating the brake rotor 503 and rotating the first grinding disc 531 a, moving said first grinding disc 531 a towards the first surface 710a of the brake rotor 503. Further, in one embodiment, the second groove is achieved by, while rotating the brake rotor 503 and rotating the second grinding disc 531 b, moving said second grinding disc 531 b towards the first surface 710b of the brake rotor 503.

In a further embodiment of the inventive concept, the grinding discs 531 a, 531 b are lowered in a vertical axis direction after said two grooves are achieved. Thereby, the grinding discs 531 a, 531 b does not impede the abrading members from abrading said brake rotor's first 710a and second 710b surface.

In one embodiment the grooves 508a, 508b are achieved through a grinding member 530 when the brake disc 502 is rotated. In another embodiment the grooves are achieved in another machine and before it is rotated in the refacing machine. In another embodiment the grooves are achieved through a grinding tool. In one embodiment the radial width of the groove is from about 0.5 mm to about 5 mm wide. In another embodiment the axial depth of the groove is about 0.1 mm to about 1 .0 mm deep.

In another embodiment, as shown in fig. 3 the method comprises additional steps. In one such embodiment a preceding step 303 is measuring the brake hub for irregularities. The measuring of the brake hub 506 can be done by coupling a dial indicator to the brake hub. In one embodiment a subsequent step 304 is decreasing irregularities, such as bent portions or dents, of the brake hub 506 through molding selected portions of the brake hub with a force comprising a component in a direction orthogonal to said first 710a or second 710b surface. In one embodiment a pulling and pushing device with a lever arm is coupled to the brake hub 506 and used to decrease above-mentioned irregularities.

In another embodiment, also shown in fig. 3 the method comprises additional steps. In one such embodiment one step 305 is measuring the brake rotor 503 for irregularities. The measuring of the brake rotor 503 can be done by coupling a dial indicator to the brake rotor. In one embodiment a subsequent step 305 is decreasing irregularities, such as bent portions or dents, of the brake rotor 503 through molding selected portions of the brake rotor 503 with a force comprising a component in a direction orthogonal to said first 710a or second 710b surface. In one embodiment a pulling and pushing device with a lever arm is coupled to the brake hub and used to decrease above-mentioned irregularities.

In yet another embodiment, as shown in fig. 4, the method comprises two additional preceding steps 401 , 402 wherein the first 401 of the two steps is applying degreasing on a least two rivets 507 holding the brake rotor 503 to the brake hub 506. Thereby, grease and dirt holding the rivet 507 in a locked position is loosen up. In one embodiment this step is done through lowering the whole brake disc 502 in a container with degreasing. In another embodiment the degreasing is sprayed on the rivets 507. The subsequent step 402, is rotating said at least two rivets to remove dirt. In one embodiment the rivets are rotated by a screw driving machine, which can be hand held or stationary. In yet another embodiment the brake rotor 503 and hub are still in a container with degreasing when the rivets 507 are rotated.

In one aspect, as shown in one embodiment in a perspective view in fig. 5, the inventive concept comprises a machine 500 for refacing brake discs 502. The machine 500 comprises a rotating member 501 . In one embodiment the rotating member 501 comprises a motor 51 1 and a drive shaft 512 coupled to a chuck 513 for receiving a brake disc 502, possibly via an adapter. Moreover, the machine 500 comprises two abrading members 505a, 505b which are arranged to simultaneously reface two surfaces 710a, 710b of the brake rotor. Also, the machine 500 comprises an oscillating member 509 for oscillating the abrading members in a movement comprising a radial component. In one embodiment the oscillating member 509 is a separate oscillator and a drive 514 coupled to the abrading members 505a, 505b.

Moreover in the embodiment as shown in fig. 5, the machine 500 has a supporting rack 515 with a pair of supporting beams 516a, 516b mechanically coupled to each other to form a stable supporting structure for the machine's components. However, other structures of the supporting rack 51 5 are possible, such as a single beam forming a circular, triangular, squared, or other geometry.

Furthermore, the machine's 500 driving member 501 in the embodiment shown in fig. 5 is arranged along an axial axle with a straight shaft 512 rotating the brake disc 502 around said axial axle, however, in other embodiments the machine's 500 driving member 501 can be arranged along a radial axle with a shaft 512 including a transmission for rotating the brake disc 502 around an axial axle. Further shown in the embodiment according to fig. 5, the machine 500 comprises an adjusting device 518 for coupling the two abrading members 505a, 505b to the supporting rack 515. The adjusting device 518 can be a sliding, rotating, step-by-step, or other type of adjusting device. The adjusting device 518 allows adjusting the abrading members' position along an axis with an axial direction component and an axis with a vertical direction component. Moreover, the adjusting device 518 can be of different types along different axes, e.g. a sliding adjusting device along the axial direction and a threaded rotating adjusting device along the vertical axis.

In one embodiment, the adjusting device 518 can adjust the abrading members about 30 mm up or down with a vertical axis component. Thereby, the abrading members' position can be adjusted to fit the size of the brake disc which is to be refaced.

In the embodiment as shown in fig. 5 of the inventive concept the machine 500 comprises a first grinding disc 531 a for grinding the first groove and a second grinding disc 531 b for grinding the second groove. Further, the first 531 a and second 531 b grinding discs are coupled to an electric motor 533, thereby they can rotate. Moreover, the grinding discs 531 a, 531 b are movable along a direction with an axial component. Thereby the grooves 508a, 508b can be achieved by moving said first grinding disc 531 a towards the first surface 710a of the brake rotor 503 and subsequently moving said second grinding disc 531 b towards the first surface 710b of the brake rotor 503, while rotating the brake rotor 503 and rotating said first and second grinding disc 531 a, 531 b.

In one alternative embodiment, a single grinding disc may be used to provide the grooves on both sides of the brake rotor. Such a single grinding disc may be axially displaceable relative to the brake rotor, such that it can be positioned to provide the groove in both sides of the brake rotor.

In another alternative embodiment, the grinding disc or discs may be replaced by a lathe or milling type cutting tool, adapted in terms of cutting width, and/or being radially controllable during grinding/cutting, for providing a groove of the desired width. Moreover, as further illustrated in fig. 5 the grinding discs 531 a, 531 b are adjustable in a direction with a vertical component. Thereby, they can be elevated to a height to achieve said grooves 508a, 508b and thereafter the can be lowered in a vertical axis direction. Thereby, the grinding discs 531 a, 531 b does not impede the abrading members from abrading said brake rotor's first 710a and second 710b surface. In one embodiment, the grinding discs are adjustable in a direction with a vertical component through adjusting legs 534 coupled to a holder 532. In another embodiment, the grinding discs are adjustable in a direction with an axial component through adjusting the axial position of said holder 532, by sliding said holder 532. Said sliding of the holder can be enabled by recesses 535 in the holder.

In one embodiment, the machine comprises a biasing device 519 for biasing the abrading members 505a, 505b in a direction with a radial component. The biasing device can comprise a spring, an elastic material or other which enables a springing ability. The biasing device 51 9 can be adjustable to increase or decrease the biasing force. In one embodiment, the biasing device 519 is adjustable through a threaded arrangement. In other embodiments the biasing device 519 can be adjustable through a sliding arrangement, or through altering a relative angle of the biasing device.

Moreover, in the embodiment shown in fig. 5, the abrading members

505a, 505b are pressed towards the brake rotor 503 by two spaced apart pressure adjusting devices 517a, 517b. The two pressure adjusting devices 517a, 517b can comprise a spring arrangement and allow adjustments of the spring force pressing the abrading members 505a, 505b towards the brake rotor 503. In other embodiments, the adjusting devices comprise an elastic material or other components enabling a springing ability. Moreover, the adjusting devices 517a, 517b can be adjusted through rotating or sliding the devices along a threaded bolt, a pin, dowel or bore.

In further one embodiment, there is a third pressure adjusting device 517c. Said pressure adjusting device 517c is arranged between the two pressure adjusting devices 517a, 517b. The third pressure adjusting device 517c, can have a similar design as the first 517a and second 517b adjusting devices, but in some embodiments it can have another design.

Moreover, the pressure adjusting devices 517a, 517b 517c can be formed to push the first abrading member towards the second abrading member and vice versa, e.g. by forming a clamp. In another embodiment the devices can be formed to pull the first abrading member towards the second abrading member and vice versa, e.g. by bolt and nut device with or without a spring.

In one embodiment, the first 517a and second 517b pressure adjusting devices are two biased bolt and nut assemblies formed to pull the abrading members together, and the third pressure adjusting means 517c is a clamp assembly formed to push the abrading members towards each other.

In fig. 6 a brake disc 502 and two abrading members 505a, 505b according to one embodiment of the inventive concept is illustrated in a perspective view. The design of a floating brake disc 502 is further illustrated with the brake rotor 503 being coupled to the brake hub 506 by means of rivets 507. In another embodiment the brake rotor 503 is coupled to the brake hub 506 by bolt and nut couplings. Furthermore, it is illustrated how the groove 508 has been provided on an inner portion of the brake rotor 503.

Moreover, the abrading members 505a, 505b according to one embodiment are illustrated in fig 6 and 7, wherein fig. 7 shows a cross- sectional view in the horizontal plane of a brake disc 502 and two abrading members in said embodiment. The abrading members 505a, 505b are two substantially square shaped members each with an outer surface 721 a, 721 b and an inner surface 722a, 722b. In the embodiment shown in fig. 7, said inner surfaces 722a, 722b are provided with an abrading effect. In one embodiment said abrading effect is achieved through arranging an abrasive paper on each of said surfaces 722a, 722b.

Moreover, in the embodiment shown in fig 6, the width of the abrading members' inner surfaces 722a, 722b is about 50 mm. However, in other embodiments the width of the abrading members' inner surfaces 722a, 722b is from about 20 mm to 100 mm, preferably from about 30 mm to about 80 mm and most preferably about 40 mm to about 60 mm. In other embodiments of the inventive concept, the abrading members 505a, 505b length is from about 120mm - 450mm, preferably from about 160 mm to about 400 mm and most preferably about 250 mm to about 350 mm.

In other em bodiments of the inventive concept, the abrading members 505a, 505b length that actually abrades the brake rotor 503 is from about 70mm to about 300mm, preferably from about 100 mm to about 250 mm and most preferably about 180 mm to about 220 mm.

Moreover, in the embodiment illustrated in fig. 5, the abrading members 505a, 505b have a recess at the center of one of the long sides. The recesses on each of said abrading members have a radius that corresponds to about half of the total length of an abrading member. Moreover said recess extends about one third of the abrading members' width along the radial axis, and extends the whole abrading members depth along the axial axis. In another embodiment, the recess only extends a portion of the abrading members' depth of along the axial axis, wherein said portion is the portion closest to the inner surface 722a or 722b of the abrading member 505a, 505b, respectively.

In fig. 8, an exploded view illustrates a part of the machine according to one embodiment of the inventive concept. Fig. 8 discloses the two abrading members 505a, 505b, the first 517a, second 517b and third 517c pressure adjusting devices 517c, the adjusting device 518, and the biasing device 519 as discussed above. Moreover fig 8 illustrates how the two abrading members 505a, 505b are aligned next to each other, and how the first 517a, second 517b and third 517c pressure adjusting means 517c are arranged relative the abrading members, i.e. in the vertically lower portion, vertically upper portion and vertically middle portion of the abrading members, respectively. Moreover, it illustrates how the adjusting device 518 and biasing device 519 are designed and arranged in the vertical lower part of the abrading members 505a, 505b.

Moreover, in one embodiment the abrading members 505a, 505b have two guiding members 820a, 820b as shown in fig 8, arranged so that the abrading members are aligned in parallel, thus resulting in that the two refaced surfaces on the brake rotor 503 becomes parallel.

As earlier discussed, the abrading members 505a, 505b are moved in an oscillating movement between an inner end position shown in fig 10 and an outer end position shown according to one embodiment shown in fig. 9. In said inner end position, at least one portion of the abrading member's 505a radially inner end 921 a is radially closer to the hub than at least one corresponding portion of the groove's 508a radially outer end 924a. However, the abrading member's 505a radially inner end 921 a is radially further from the hub than the groove's 508a radially inner end 923a. That is, in the embodiment shown in fig. 9 the abrading member's 505a radially inner end 921 a is, in at least one portion, arranged radially between the groove's 508a radially inner end 923a and radially outer end 924a.

In the embodiment shown in fig. 10, the abrading member 505a is located in an outer end position. In said outer end position, at least one portion of the abrading member's 505a radially outer end 922a is radially further from the hub than a corresponding portion of the brake rotors' 503 radially outer end 925a. However, the abrading member's 505a radially inner end 921 a is radially closer to the hub than the brake rotors' 503 radially outer end 925a. That is, in the embodiment shown in fig. 9 a portion of the brake rotors' 503 radially outer end 925a is arranged radially between a corresponding portion of the abrading member's 505a radially inner end 921 a and radially outer end 922a.