EP0359304B1 - Method and apparatus for the copy grinding of cylindrical or spherical surfaces - Google Patents

Abstract

Provided before a method consisting of precision grinding with subsequent finish grinding is a grinding phase in which the grinding belt (21) is movably pressed under predetermined pressure against the outer surface (45') of the preheated cylinder (45) to be machined within a certain clearance X or X', adjustable by means of an adjusting device (30), between a copying template (10) and a contact roller (23) in such a way that, in this preliminary grinding phase, stock is uniformly removed from the cylinder surface (45') irrespective of its geometry. After a surface layer of the cylinder (45) formed from various particles has been ground down, the proportional pressures applied to the belt-grinding unit (1) are changed in such a way that, in the now following first grinding phase, the actual precision grinding, a fixed connection is set between the copying template (10) and the contact roller (30). A uniform distribution of temperature and thus also a uniform expansion of the cylinder surface (45'), which is of importance especially in the radial direction, are thereby ensured, as a result of which a more accurate cylinder geometry is achieved. <IMAGE>

Description

The invention relates to a method for copy grinding a cylindrical or spherical surface according to the preamble of claim 1 and to a belt grinder for carrying out the method according to the preamble of claim 2.

A method and a belt grinder of the type mentioned are known from DE-OS 36 39 264. With this belt grinder there is always a rigid connection between the belt grinder and the copying template, so that the surface to be machined is ground in rigid settings. When regenerating cylinders for paper machines, there is the problem that after prolonged use, such cylinders are provided with a surface layer, the so-called coating, which consists of various substances such as resin, oil, paint residues and the like. This surface layer must be removed before the cylinder surfaces are actually processed. In order to regenerate such cylinders, they are brought to operating condition, ie a certain temperature (for example 150 ° - 170 ° C), a certain pressure (for example 8 bar) and a certain number of revolutions. By means of the previously known rigid belt grinder, the highest unevenness is now removed, so that after the first pass, bare spots alternate with those on which the surface layer, the so-called coating, is still present. The bare layers radiate less heat than the coated areas, so that the bare areas have a higher temperature than the coated areas. This leads to uneven thermal expansion machining surface, which ultimately leads to inaccuracies, so-called holes, in the machined surface.

The object of the invention is to design a method and a belt grinder of the type mentioned at the outset in such a way that the disadvantages mentioned are avoided.

• a) bei dem eingangs genannten Verfahren durch die kennzeichenden Merkmale des Anspruches 1; und
• b) bei dem eingangs genannten Bandschleifgerät durch die kennzeichnenden Merkmale des Anspruches 2.

The object is achieved according to the invention:

• a) in the aforementioned method by the characterizing features of claim 1; and
• b) in the belt grinder mentioned at the outset by the characterizing features of claim 2.

Due to the fact that there is play in the feed direction of the feed slide between the longitudinal slide connected to the copying template and the feed slide connected to the belt grinding device, and because the feed slide is pre-tensioned relative to the longitudinal slide in the direction of the surface to be machined, the feed slide can and so that the belt grinding device is brought into contact with the surface to be machined in such a way that the driver can oscillate around the play X between the stops. This results in a floating guidance of the belt grinding device so that it can adapt to the unevenness, ie heights and depths, of the surface to be machined during the pre-grinding. The result of this is that during pre-grinding the belt grinding device follows the entire contour of the surface evenly and thus the surface layer, ie the coating, is evenly removed over the entire surface to be processed. Individual bare spots and thus different thermal expansion are avoided.

After pre-grinding, the direction of action of the pretensioner is used for shape grinding, i.e. Copy grinding according to the copy template, vice versa, so that the feed carriage is biased against the feed direction, i.e. the driver is biased against the stop of the adjusting device, which ensures a rigid connection between the copy template and the belt grinding device when the feed carriage is delivered to the surface to be processed. The shape grinding can be carried out in a known manner.

The new process and the new belt grinder enable a higher accuracy of the surface to be machined, but also shorter grinding times with less material removal and thus a longer service life of the cylinder to be machined as well as a saving of grinding belts.

Advantageous embodiments of the belt grinder are described in claims 3 to 5.

A particularly expedient embodiment of the belt grinder is described in claim 3.

There are various possibilities for the design of the pretensioning device, for example mentioned in claim 4.

A development according to claim 5 is particularly expedient since the heating plate prevents the carrier from heating up, so that the carrier does not have to be brought to the operating temperature of the surface to be machined beforehand. On the one hand, this reduces the processing times due to the absence of warming up, and on the other hand increases the accuracy of the processing.

• Figur 1 ein Bandschleifgerät in Ansicht quer zur Längsverschiebung;
• Figur 2 das Bandschleifgerät der Figur 1 in Draufsicht;
• Figur 3 eine Justiereinrichtung im Längsschnitt und in Formschleif-Stellung; und
• Figur 4 die Justiereinrichtung der Figur 3 in Vorschleif-Stellung.

An exemplary embodiment of the invention is illustrated in more detail below with reference to the drawings, in which:

• Figure 1 shows a belt grinder in a view transverse to the longitudinal displacement;
• Figure 2 shows the belt sander of Figure 1 in plan view;
• Figure 3 shows an adjusting device in longitudinal section and in the form grinding position; and
• Figure 4 shows the adjusting device of Figure 3 in the pre-grinding position.

Figures 1 and 2 show a machine frame 9, on which a console 2 for holding a carrier 4 arranged on a base plate 3 is provided. On the carrier 4 there are on the one hand a guide track 7 for support rollers 8 arranged on a longitudinal slide 19 and on the other hand a copying template 10. The copying template 10 rests on supports 11, which are in turn mounted in receptacles 12, which can be adjusted on both sides by means of adjusting screws 13 (only the screw axes are indicated) to the desired nominal dimension of the surface 45 ′ to be machined, of a cylinder 45 with the radius R ( see DE-OS 36 39 264). The carrier 4 is shielded from the surface to be machined 45 'of the cylinder 45 by a heat insulation plate 5 arranged on holders 6.

The longitudinal slide 19 is supported on the one hand by means of support rollers 8 on the guide track 7 and on the other hand by means of guide bushings 20 on the copying template 10. The longitudinal slide is movable along the carrier 4. For this purpose, a drive motor 14 with a gear 15, which drives a gear 16, which meshes with a rack 16 ', which is arranged near the guide track 7 on the carrier. On the longitudinal slide 19, a feed slide 18 is slidably mounted in the feed direction. The feed carriage 18 carries a belt grinding device via a holder 26 and a tensioning device 27. The latter contains a grinding belt 21 guided over a drive roller 22 and a contact roller 23.

The guidance of the belt grinding device by means of the guide bushes 20 on the copying template 10 ensures that the contact roller 23 of the belt grinding device is tangential to the surface 45 'of the cylinder 45 in any position, so that a smooth surface can be ground without scoring. The tensioning device 27 with the adjusting screw 28 and the tensioning cylinder 27 'is used for tensioning the grinding belt 21. The contact roller 23 guides the grinding belt 21 to the surface 45' to be machined. The grinding belt 21 is driven by means of the drive roller 22, which is coupled to a drive motor 24. The belt grinder is provided with a protective cover 25. A suction device 29 serves to suck off the abrasion material at the grinding point.

The feed of the belt grinding device radially to the surface to be machined 45 'of the cylinder 45 takes place via the feed slide 18 by means of an adjusting device 30. This contains a threaded spindle 31 which is mounted on the one hand in a threaded member 40 which is arranged on a base plate 17 which on the one hand is rigidly connected to the longitudinal slide 19 and on the other hand, the feed slide 18 is guided displaceably in the feed direction. Furthermore, the threaded spindle is mounted in a bearing 33, for example made of ball bearings, which is arranged in an intermediate piece 38, which is connected to the feed slide via a screw 41 18 is connected. A clamping ring 34 serves to fasten the bearing 33 to the intermediate piece 38.

The threaded spindle 31 contains a stop ring 32 secured by means of a pin 32 and a further screwed-on stop ring 37 with a slot 37 'for attaching a tool. Between the stop rings 32, 37, the bearing 33 can be displaced by the total play X. At the spindle end 31 'a disk 39 is fixed by means of a pin 31 ", which has an eccentrically arranged handle 39'. The disk 39 carries a scale ring 35 which is rotatably arranged on the disk 39 and is secured by means of a rubber ring 36 against unintentional displacement The scale ring 35 overlaps the intermediate piece 38 and interacts with a scale, not shown there, by means of the scale ring 35. The position of the bearing 33 between the stop rings 32 and 37, which is desired during the pre-grinding, can be set, as will be explained below.

Between the feed slide 18 and the longitudinal slide 19 there is a pretensioning device 43 which is supported on the feed slide 18 via a holder 42. The pretensioning device can be designed as a hydraulic or pneumatic piston / cylinder unit or, if appropriate, also as a spring device. The control of the pretensioning device is such that it exerts a pretension in the direction of the surface to be ground 45 'during pre-grinding, so that the bearing 33 serving as a driver is in contact with the stop ring 32 which faces the contact roller 23. During pre-grinding, the feed carriage is in this setting of the pretensioner against the surface to be ground 45 'of the cylinder 45 and thus the grinding belt 21 is brought into contact by means of the contact roller 23. By turning the threaded spindle 31 further by means of the handle 39 ' the stop ring 32 is lifted from the bearing 33. The size of the lift-off and thus the position of the bearing between the stop rings 32, 37 can be read off by means of the scale ring 35 and the scale attached to the intermediate piece 38. The position is expediently set such that the distance, ie the play X1 between the stop ring 32 and the bearing 33 is equal to the distance, ie the play X2 between the stop ring 37 and the bearing 33. The sum of the games X1 and X2 results in the total game X. This floating guidance of the belt grinding device enables the contact roller 23 to evade in both directions of the infeed direction. For the form grinding, in which the contact roller 23 must be guided in accordance with the copying template 10, the pretensioning device 43 is switched over, so that the feed carriage 18 is biased opposite to the surface 45 'to be treated, ie the bearing 33 is against the stop ring 37 facing away from the contact roller 23 biased, as shown in Figure 3. The game X2 between the bearing 33 and the stop ring 37 is zero. The guide bushing 20 thus transmits the guide along the copying template 10 without any possibility of evasion, ie rigidly and thus without play to the feed carriage 18 and thus into the contact roller 23.

The belt sander operates as follows.

For pre-grinding a surface to be machined 45 'of the cylinder 45, a coarse grinding belt 21 is first placed on the belt grinding device. The pretensioning device 43 is then switched over such that the feed carriage 18 is pretensioned against the stop ring 32 of the adjusting device 30 facing the contact roller 23. The cylinder to be treated is preheated to operating temperature, for example by means of steam, at 150 ° to 170 ° C. and placed under an internal pressure of, for example, 8 bar and brought into circulation. The belt grinder prepared above will by means of the adjusting device 30 by turning the handle 39 'against the surface to be machined 45' until the grinding belt 21 is in contact with the surface on the contact roller. Then the threaded spindle is further advanced by means of the handle, for example by a further two rotations, until it can be seen on the scale ring 35 and the intermediate piece 38 that the bearing 33 is located approximately in the middle between the stop rings 32 and 37, that is to say the same play on both sides of X1 = X2 = X / 2. The belt grinder is moved back and forth along the surface 45 'of the cylinder in several passes, if necessary after the belt 21 has been replaced, until the surface layer, the so-called coating, has been removed and there is a rough pre-grinding of the surface. In this pre-grinding phase, the belt grinding device is guided in a floating manner and adapts to the surface structure of the surface to be treated.

After the pre-grinding is finished, a finer grinding belt is clamped on the belt grinding device for shape grinding, ie copy grinding according to the copying template, and the pretensioning device 43 is switched over so that the bearing 33 abuts against the rear stop ring 37. After switching on the belt grinding device, this is fed in a known manner via the feed carriage 18 by means of the adjusting device 30 to the desired grinding depth and guided back and forth according to the copying template 10 along the surface 45 to be machined. The grinding process is repeated in several passes, the required infeed depths and, if necessary, after the grinding belts 21 have been replaced, until the desired surface profile and the desired surface quality are achieved.

REFERENCE SIGN LIST

• 1 belt sander
• 2 console
• 3 base plate
• 4 carriers
• 5 thermal insulation panel
• 6 holders
• 7 guideway
• 8 support roller
• 9 machine frame
• 10 template
• 11 support
• 12 recording
• 13 adjusting screw
• 14 drive motor
• 15 gears
• 16 gear
• 16 ′ rack
• 17 base plate
• 18 delivery slides
• 19 longitudinal slides
• 20 guide bush
• 21 sanding belt
• 22 drive roller
• 23 Contact role
• 24 drive motor
• 25 protective cover
• 26 holder
• 27 tensioning device
• 27 ′ clamping cylinder
• 28 adjusting screw
• 29 suction device
• 30 adjustment device
• 31 threaded spindle
• 31 ′ spindle end
• 31˝ mounting pin
• 32 stop ring
• 32 ′ fastening pin
• 33 bearings
• 34 drivers
• 35 scale ring
• 36 rubber ring
• 37 stop ring
• 37 ′ slot
• 38 intermediate piece
• 39 disc
• 39 ′ handle
• 40 threaded link
• 41 fastening screw
• 42 holder
• 43 pretensioning device
• 45 cylinders
• 45 ′ cylinder outer surface
• X total game
• X1 Play between the stop ring and the bearing
• X2 Play between the bearing and the stop ring
• R radius of the cylinder

Claims (5)

1. Method for the contour grinding of cylindrical and spherical surfaces by means of a belt grinding apparatus, in particular for the regeneration of cylinders (45) for paper machines and shafts, with the following method steps:

   - the surface (45′) to be machined is brought to operating conditions,

   - the grinding belt (21) of the belt grinding apparatus, running over a contact roller (23), is brought by means of a drive (22 - 24) to a predetermined speed and guided into a grinding position relative to the surface (45′) to be machined, with a controllable, firm contact being established with the aid of a movable adjusting, device (30),

   - in a first shaping-grinding phase, the belt grinding apparatus (1) passes with to-and-fro movements in the axial direction parallel to a shaping plate (10) over the entire length of the surface (45′) to be machined,

   - after each pass there takes place by means of a feed slide (18) with the adjustment device (30), a corresponding feed motion of a contact roller (23),

   - after the grinding belt (21) has worn it is exchanged, with a further corresponding adjustment of the feed slide (18),

   - the passes with the corresponding feed movements are repeated, as well as the exchanging of grinding belts (21), until the surface (45′) has the shape determined by the shaping plate (10) in the axial direction and has a precise roundness,

   - by using progressively finer grinding belts (21), a second shaping-grinding phase is carried out, in which phase there is achieved an exact and correspondingly fine surface (45′) required according to the manufacturing process,

   characterised in that, in a rough-grinding phase upstream from the first shaping-grinding phase, the grinding belt (21) is pressed in a movable manner under a pre-determined pressure against the surface (45′) to be machined, with play (X) between the shaping plate (10) and the contact roller (23), in such a way that the contact roller (23) can, independently of the shaping plate (10), follow the unevenness of the surface (45′) to be machined, and in that, after a surface layer of the surface (45′) to be machined has been ground away, the pressure ratios on the belt grinding apparatus (1) are changed in such a way that, in the first shaping-grinding phase now following, contact without play results between the shaping plate (10) and the contact roller (30).
2. Belt grinding apparatus for carrying out the method according to claim 1, having a carrier (4) arranged alongside the surface (45′) to be ground, having a shaping plate (10) which guides a longitudinal slide (19) which can be moved along the carrier, against which longitudinal slide a feed slide (18) is arranged in a movable manner and so that it can be advanced by means of an adjusting device (30) against the surface (45′) to be machined, with the feed slide (18) carrying a belt grinding device with a contact roller (23) facing the surface (45′) to be machined, characterised in that the adjusting device (3) has, for coupling the feed slide (18) to the longitudinal slide (19), a driver (33, 34) which can be displaced by the play (X) between two limit stops (32, 37) along a sliding body (31) extending in the feed direction of the feed slide (18), there being a pre-stressing device (43) acting in the feed axis between the feed slide (18) and the longitudinal slide (19) and pre-stressing the feed slide (18) during the rough-grinding phase in the direction of the surface (45′) to be machined and in the opposite direction during the shaping-grinding phase.
3. Belt grinding apparatus according to claim 2, characterised in that the adjusting device (30) has a threaded spindle forming the sliding body (31) which is supported in a threaded element (40) connected to the longitudinal slide (19) and in a bearing connected to the feed slide (18), the bearing (33) being formed as a driver and being displaceable by the play (X) between two limit stops (32, 37) arranged on the threaded spindle (31).
4. Belt grinding apparatus according to claim 2, characterised in that the pre-stressing device (43) is in pneumatic, hydraulic or spring form.
5. Belt grinding apparatus according to claim 2, characterised in that the carrier (4) is shielded from the surface (45′) to be machined, by means of a thermal insulation plate (5).

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