EP0325799A2 - Centrifugal force machining apparatus - Google Patents

Abstract

A centrifugal machine for mechanical processing, e.g. Grinding, polishing, cleaning and deburring of workpieces, with a processing container for receiving the workpieces and the processing means, which has an essentially cylindrical casing (1) and a rotating base (2) mounted coaxially therewith in the form of a plate or the like. Has. With its peripheral edge, the bottom protrudes from the cylindrical jacket to form a narrow gap (3). The jacket can be raised and lowered automatically in relation to the floor for fine adjustment of the width of the gap over the entire circumference of the container depending on the given or changing gap width. This is done by a measuring device (14) for measuring the width of the gap (3) and by a device (8, 9) for the jacket (1), which can be controlled by the measuring device in such a way that the gap width is set to a certain value or is kept at this value.

Description

The invention relates to a centrifugal machine for mechanical processing, e.g. Grinding, polishing, cleaning and deburring of workpieces, with a processing container for receiving the workpieces and the processing means, which has a substantially cylindrical jacket and a rotating base coaxially mounted thereto or the like. has, which protrudes with its peripheral edge to the cylindrical jacket to form a narrow gap. The container casing and the rotating base can be mounted on a common support device or on separate support devices. In the machine relating to the invention, the jacket can also be raised and lowered relative to the floor for fine adjustment of the width of the gap over the entire circumference of the container.

A machine with a container casing that can be raised and lowered to adjust the gap relative to the rotating base is already known (EP-B1-0 171 527). The gap width can be adjusted or adjusted to the desired size. Adjustment is highly useful or necessary if the gap width has changed during operation of the machine due to wear on the walls delimiting the gap or due to swelling or thermal expansion of the material of the container shell or the rotating base.

The gap can be reduced by more than 1 mm due to thermal expansion of the container shell and in particular the container base, depending on the material properties, if the workpiece holder rises from room temperature before the machine is started up to over 80 ° C during operation due to the grinding and Friction warmed up. The wear of the walls of the container delimiting the gap is also not inconsiderable, which is caused by the constant removal of the abrasive used in the workpiece holder together with the processing liquid through the gap during processing.

However, in particular for workpieces of small dimensions to be machined, a certain gap width is of great importance in order on the one hand to prevent the workpieces from penetrating into the gap, with the result that the workpieces and the walls of the container delimiting the gap are damaged, and on the other hand too much liquid and Avoid abrasive drainage through the gap.

In the aforementioned known machine, the fine gap adjustment occurs in that adjusting screws are provided for raising and lowering the container jacket, by means of which the container jacket is supported uaf of its carrying device. However, this manual readjustment can only guarantee an exactly constant gap width if it is carried out exactly in accordance with the change in the gap width, which requires constant observation or registration of the gap width or its change on the one hand and frequent and exact readjustment.

The invention is therefore based on the object of avoiding the problems existing in the previously known machines with manual adjustment of the gap width, i.e. to design a machine in which a constant gap width is guaranteed without the need for constant control. This is achieved according to the invention in that the lifting and lowering of the container casing relative to the floor takes place automatically as a function of the given or changing gap width, for which purpose a mechanical, hydraulic, pneumatic or electronic measuring device is provided for measuring the width of the gap, which is connected to a device for the automatic lifting and lowering of the jacket, which can be controlled by the measurement results of the measuring device in such a way that the gap width is set to a certain value or is kept at this value. With such a device, a desired gap width is automatically kept constant over the entire working process of the machine, which ensures that relatively thin workpieces with a dimension of less than 0.5 mm can be processed without penetration and locking of the workpieces in the Gap occurs with the result of destruction or damage to the edges of the container shell or rotating bottom delimiting the gap.

The above-mentioned measuring device provided in the machine according to the invention can be formed by a hydraulic or pneumatic dynamic pressure gauge which is arranged in a line supplying the gap with a liquid or gaseous medium and which measures the dynamic pressure of this medium changing in this supply line as the gap width changes. The measurement of the dynamic pressure can be more commercially available using a pressure sensor, for example an inductive or piezoresistive pressure transmitter Type (eg make "Jumo" from MK Juchheim GmbH & Co., Fulda / FRG), whereby the measured pressure or the measured pressure changes are converted into electrical signals for controlling the lifting and lowering device. Further possible measuring devices are specified in the patent claims.

The device for the automatic lifting and lowering of the container casing can advantageously be formed by one or more elastically compressible, pneumatically or hydraulically actuated cushions, which rest on the circumference of the container on a support device fixed at a constant height relative to the rotating floor and carry the container casing. The cushion or cushions can be formed by a hose or by corresponding hose sections, which are arranged on the circumference of the container between the support device and the container jacket. However, the pillows can also consist of several bellows or so-called air springs, or else of pneumatic or hydraulic lifting cylinders, the pneumatic or hydraulic filling of which can be controlled by the measuring device measuring the gap width. Vertically operating threaded spindles can also be used for this purpose, which can be driven by motors connected to and controlled by the measuring device.

• Fig. 1 zeigt das erste Ausführungsbeispiel im Axialschnitt durch den Werkstückaufnahmebehälter und seine Trag- und antriebseinrichtung;
• Fig. 2 veranschaulicht die bei diesem Ausführungsbeispiel vorgesehene Meßeinrichtung für die Spaltweite im Schnitt in größerer Darstellung;
• Fig. 3 zeigt den bei diesem Ausführungsbeispiel zum Heben und Senken des Behältermantels vorgesehenen hydraulischen oder pneumatischen Schlauch im Schnitt in zwei unterschiedlichen Positionen;
• Fig. 4 zeigt ein zweites Ausführungsbeispiel der erfindungsgemäßen Maschine in gleicher Darstellungsweise wie Fig. 1;
• Fig. 5 ist ein Schnitt durch einen Balg der Heb- und Senkeinrichtung dieses Ausführungsbeispiels;
• Fig. 6 veranschaulicht das dritte Ausführungsbeispiel der erfindungsgemäßen Maschine in gleicher Darstellungsweise wie Fig. 1;
• Fig. 7 zeigt eine Einzelheit von Fig. 6 in vergrößerter Schnittdarstellung.

Particularly advantageous exemplary embodiments of the centrifugal processing machine according to the invention are described in more detail below with reference to the drawing:

• Fig. 1 shows the first embodiment in axial section through the workpiece receptacle and its support and drive device;
• Fig. 2 illustrates the measuring device for the gap width provided in this embodiment in section in a larger representation;
• Fig. 3 shows the hydraulic or pneumatic hose provided in this embodiment for lifting and lowering the container casing in section in two different positions;
• Fig. 4 shows a second embodiment of the machine according to the invention in the same representation as Fig. 1;
• Fig. 5 is a section through a bellows of the lifting and lowering device of this embodiment;
• FIG. 6 illustrates the third exemplary embodiment of the machine according to the invention in the same representation as FIG. 1;
• Fig. 7 shows a detail of Fig. 6 in an enlarged sectional view.

In all of the exemplary embodiments shown, the processing container is formed by an upper cylindrical casing 1 and a lower rotating plate-shaped base 2 which is coaxially mounted thereon and which extends with its circumferential rank to the lower edge of the casing to form a gap 3. Arranged below the plate-shaped base is a collecting container 4 for the processing liquid flowing through the gap 3, through the base of which the drive shaft 5 of the plate-shaped base passes through, which can be driven via the drive motor 6 arranged under the collecting container 4.

The lower collecting container 4 also forms the supporting device for the container jacket 1. For this purpose, this container, which is circular in plan view in the exemplary embodiment according to FIGS. 1 to 3, has at its upper edge a radially projecting flange 7 which runs around the entire container edge and has a flange on the upper side thereof Circumferential depression is arranged, in which a ring-shaped circumferential hydraulic or pneumatic elastic pressure hose 8 is mounted, the cross-section of which is essentially radially compressible. A line 9 is provided on this pressure hose for the supply and discharge of the liquid or gaseous medium used to fill and pressurize it. The container 1 rests on this pressure hose 8 with a flange 10 which is arranged on its lower edge and also projects radially and which, like the flange 7 of the lower container 4, has a depression on its side facing the hose, into which the hose engages.

Due to the weight of the container jacket 1, the hose 8 is subjected to a load acting on its upper side, which attempts to compress it from its circular cross-sectional shape shown in FIG. 3 into a flattened cross-sectional shape, also shown in this figure, with a smaller cross-sectional height. Depending on the pressure level of the hydraulic or pneumatic pressure medium in the hose, this compression can be prevented or its extent can be controlled. With the possible lifting and lowering of the container casing 1, the width of the gap 3 is changed, which gap is shown in the

Embodiment extends approximately at an angle of 45 ° to the container axis. However, other angular positions of the gap with respect to the container axis are also possible, the change in the height of the container shell being made smaller by the lifting and lowering device formed by the pressure hose 8, the smaller the angle of inclination of the gap to the container axis.

For the sake of the least possible abrasion of the edges of the rotating base 2 and the container casing 1 on the inside of the gap 3, it should be expedient to choose the inclination of the gap 3 to the container axis X in such a way that no sharp edges occur at the aforementioned edges.

It is possible that the pressure hose 8 does not extend over the entire circumference of the container, but only over a large part thereof. It is also possible to provide a plurality of hose sections, each of which extends only over part of the container circumference, each of which is connected via a line 9 to the pressure source for supplying these sections with pressure medium. In these cases, however, a separate seal should be provided between the two flanges 7, 10 of the collecting container 4 and the jacket 1 of the processing container.

In order to maintain the central position of the container casing 1 with respect to the rotating base 2, guide bolts 11 are provided which are uniformly distributed over the circumference of the container casing 1 and which extend axially parallel to the container axis X and are fastened with their ends to the flange 7 of the carrying device 4 by screwing. These guide bolts reach through Bores in the flange 10 of the container shell 1, whereby it is guided up and down on the guide pin. The guide bolts are provided at their end located above the flange 10 with a compression spring 12, which is supported on the one hand on the head 13 of the guide bolt and on the other hand on the top of the flange 10 and to press the container jacket 1 against the carrying device 4 by compressing the hose 8 looking for.

The measuring device used to raise and lower the container shell consists in this embodiment of a pressure transducer 14 which is arranged in a hydraulic or pneumatic feed line 15 which opens into the gap 3 at the lower edge of the container shell 1. Liquid or gaseous medium is introduced into the gap through this feed line, in such a way that this medium strikes the edge of the base 2 delimiting the gap 3 approximately perpendicularly. The outflow of this medium out of the gap depends on the gap width. The resulting dynamic pressure in the supply line 15 in the medium becomes smaller when the supply is constant, if the gap 3 widens, and larger if the gap becomes narrower. This dynamic pressure change is measured by the pressure transducer and converted into electrical signals, which are transmitted via electrical lines 18 to an electronic control device, not shown in the drawing. This control regulates, for example, a pressure control valve, not shown in the drawing, which is arranged in the line 9 leading from the medium source to the hose 8, the level of the medium pressure in the hose 8. Thus, the dynamic pressure values determined by the pressure transducer 14 in the feed line 15, which display the gap width for automatic up and down movement of the Serve container shell 1 and thus for the automatic adjustment of the width of the gap 3.

The provided in this embodiment, extending around the entire container circumference pressure hose 8 not only serves to raise and lower the container shell 1, but also has the advantageous effect of a good seal between the container shell and the container 4 carrying it, which leads to the fact that the processing liquid flowing out of the processing container through the gap 3 is completely collected in the collecting container 4.

The exemplary embodiment shown in FIGS. 4 and 5 differs with regard to the design and arrangement of the casing 1 and the plate-shaped bottom 2 of the processing container, the gap 3 located therebetween, the collecting container 4 serving as a supporting device for the casing, the storage and the drive of the base 2 and the leadership of the container jacket not or essentially not from the embodiment of FIGS. 1 to 3, so that the same reference numerals are used in the drawing for the same parts. In this embodiment, the device for lifting and lowering the jacket 1 of the processing container is not formed by a circumferential pressure hose, but by pressure bellows 19 arranged uniformly distributed over the circumference of the container, which in the same way as the pressure hose 8 in the embodiment according to FIGS 3 are connected to a feed line 20 for hydraulic or pneumatic pressure medium. Instead of these pressure bellows, differently designed pressure pads can also be provided. In this case, a temperature measuring device 21, which protrudes into the collecting container 4, is used to measure the gap width Has temperature sensor 22 which measures the temperature of the liquid in this container 4. The measured values determined by the temperature measuring device 21 are passed on electrically via signal lines 23 to the device serving to control the pneumatic or hydraulic pressure in the pressure bellows 19 or pressure cushion.

In this embodiment, the gap width is therefore not scanned directly, but is only measured indirectly via the temperature of the liquid which runs through the gap 3 into the collecting container 4, on which temperature the thermal expansion of the parts of the processing container depends, which influences the width of the gap .

6 are the processing container with jacket 1 and bottom 2, the gap 3, the container 4 forming the supporting device for the jacket 1 and the drive for the tank bottom 2 and the guide for the up and down movement of the container jacket 1 in the same manner as in that of FIGS. 1 to 3 and provided with the same reference numerals. In this exemplary embodiment, pneumatic or hydraulic lifting cylinders 24 serve as lifting and lowering devices, which are arranged on the flange 7 of the collecting container 4 evenly distributed over its circumference and have pistons 25 projecting upwards against the flange 10 of the jacket 1 of the processing container, on the end face of which Jacket 1 rests with its flange 10. These cylinders are connected via pneumatic or hydraulic lines 26 to a pressure medium source which controls the supply of the aforementioned lifting cylinders 24 with pressure medium. This control is carried out via a measuring device, which in this embodiment is a mechanical, in the gap movable sensor 27 is formed. This sensor is slidably mounted in the lower edge of the jacket 1 delimiting the gap 3 in the direction of the gap width in a housing 32 inserted into the jacket 1 and can with its head act on it from time to time until it comes into contact with the system the edge of the bottom 2 are advanced. The position of the sensor 27 in this advanced position is measured by an inductive probe 28 and displayed on a dial gauge 29. The measurement result is passed on via signal lines 30 to the control of the pressure medium source for feeding the lifting cylinders 24.

If the sensor 27 is not constantly in contact with the wall of the rotating floor 2 during operation of the processing machine, severe wear is prevented. Through automatic control, this sensor can be briefly pushed into the edge of the rotating floor 2 at adjustable or fixed time intervals, for example every 15 or 30 minutes, during operation of the machine and can be retracted to a starting position immediately after measuring the gap width in which the Sensor is not on the edge of the floor.

In order to ensure a sufficient seal between the jacket 1 of the processing container and the collecting container 4 located underneath in this exemplary embodiment, an elastic sealing ring 31 is arranged between the two flanges 7, 10 thereof.

It is also possible to use essentially vertically operating threaded spindles or the like. to be provided as a lifting and measuring device, preferably on the support device for the jacket 1 of the processing container, for example in the illustrated embodiments on the flange 7 of the Collecting container 4, are stored and carry the jacket 1, which threaded spindles can be driven by motors connected to the measuring device and controlled by it.

It is also possible to arrange the measuring device outside the lower edge of the container casing 1 and to let it act outside the gap 3 on a widening of the edge of the rotating base 2 provided in this direction.

If the lifting and lowering device according to the invention is of a pneumatic or hydraulic type, such as, for example, in the exemplary embodiments according to FIGS. 1 to 5, it may be expedient for organs which can be controlled by hand in the pneumatic or hydraulic feed lines to individually adjust the lifting and lowering pressure thereof Device are provided independently of the measurement results of the measuring device in order to be able to raise and lower the jacket 1 of the processing container independently of the measurement results of the measuring device.

Claims (13)

1. Centrifugal machine for mechanical processing, e.g. Grinding, polishing, cleaning and deburring of workpieces, with a processing container for receiving the workpieces and the processing means, which has an essentially cylindrical jacket and a rotating bottom coaxially mounted to it in the form of a plate or the like. has, which projects with its peripheral edge to the cylindrical jacket to form a narrow gap, the jacket against the floor for fine adjustment of the width of the gap can be raised and lowered over the entire circumference of the container, characterized in that a mechanical, hydraulic, pneumatic or Electronically operating measuring device (14; 27, 28) is provided for measuring the width of the gap (3), which is provided with a device (8, 9; 19, 20; 24, 25, 26) for the automatic lifting and lowering of the jacket ( 1) is connected, which can be controlled by the measurement results of the measuring device in such a way that the gap width is set to a certain value or is kept at this value. 2. Machine according to claim 1, characterized in that the measuring device (14) is formed by a hydraulic or pneumatic dynamic pressure gauge which is arranged in a hydraulic or pneumatic feed line (15) which on one of the two the gap (3) delimiting walls approximately perpendicular to opposite gap wall directed into or near the gap opens. 3. Machine according to claim 2, characterized in that the hydraulic or pneumatic feed line (15) in the gap (3) delimiting the lower edge of the container shell (1) is arranged. 4. Machine according to claim 2, characterized in that the dynamic pressure meter has a pressure transmitter which emits its measurement results electrically. 5. Machine according to claim 2, characterized in that the measuring device (27, 28) comprises at least one mechanical sensor (27) which is displaceably mounted on or near the lower edge of the jacket (1) delimiting the gap (3), that it can be moved to bear against the opposite peripheral edge of the base (2). 6. Machine according to claim 1, characterized in that the measuring device is a temperature measuring device (21) which is connected to the drive or the device for lifting and lowering the container shell and has a temperature sensor (22) which in a collecting space ( 4) is arranged below the bottom (2) or container jacket (1) and measures the temperature of the liquid in the collecting space or in the container interior. 7. Machine according to claim 2, characterized in that the device (8, 9; 19, 20) for the automatic lifting and lowering of the container casing is formed by one or more elastically compressible, pneumatically or hydraulically actuatable cushions (8; 19) or dim on the container circumference on an in Fixed support (4) lying on the fixed height relative to the floor (2) and wearing the jacket (1). 8. Machines according to claim 7, characterized in that the cushion (8) is formed by an elastic annular circumferential hose or by corresponding hose sections, which is or are arranged between the support device (4) and the container jacket (1). 9. Machine according to claim 8, characterized in that the elastic hose or the hose sections has or have an inner diameter of 15 to 30 mm. 10. Machine according to claim 7, characterized in that the cushion (19) is formed by one or more pneumatic or hydraulic springs or bellows. 11. Machine according to claim 1, characterized in that the device (24) for the automatic lifting and lowering of the container jacket (1) is formed by piston-cylinder units (24, 25) distributed over the container circumference. 12. Machine according to claim 1, characterized in that the device for the automatic lifting and lowering of the container casing (1) is formed by distributed over the container circumference, essentially vertically working and motor-driven threaded spindles. 13. Machine according to one or more of claims 5 to 10, characterized in that in the feed lines (9, 20) of the pneumatic or hydraulic lifting and lowering device (8, 9; 19, 20) manually controllable elements for individual adjustment of the lifting and lowering pressure are provided independently of the measurement results of the measuring device (14; 27, 28).

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