Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23C—MILLING
  • B23C3/00—Milling particular work; Special milling operations; Machines therefor
  • B23C3/02—Milling surfaces of revolution
  • B23C3/05—Finishing valves or valve seats
  • B23C3/051—Reconditioning of valve seats
  • B23C3/053—Reconditioning of valve seats having means for guiding the tool carrying spindle
  • B23C3/055—Reconditioning of valve seats having means for guiding the tool carrying spindle for engines

Definitions

• Valve seat processing devices are used to unscrew the valve seat rings on cylinder heads of internal combustion engines, so that these seats can be replaced by new valve seat rings which are used after cooling and are given a press fit by the subsequent heating.
• such devices are used to rework valve seats on cylinder heads in order to achieve their exact fit for the valves or to restore them in the course of revision work.
• Valve seat processing devices of this type have a swivel ball that can be clamped to the device, through the center of which a guide sleeve runs, in which a spindle that also acts as a guide mandrel is rotatably mounted.
• the spindle carries a chuck below the guide sleeve, in which a turning tool can be clamped at an oblique angle to the spindle axis.
• This rotary steel has for turning the Ven ⁇ tilsitzringe a cutting edge, for finishing the Valve seats in the valve seat rings preferably three cutting edges which are at certain angles to one another.
• the spindle is inserted from the side of the valve seat into the valve guide of the valve seat to be machined and is optimally centered therein, for which purpose some devices are equipped with an automatic centering device.
• the swivel position of the guide mandrel or of the spindle is secured by the swivel ball being clamped in the device.
• the machining is now carried out by rotating the guide mandrel or the spindle with the turning steel and slowly lowering it in the swivel ball bearing.
• the turning can be done by hand or by means of a mechanical, electrical, hydraulic or pneumatic drive means.
• valve seat machining devices have the disadvantage that the machining depth can only be determined with difficulty and is very difficult to maintain from seat to seat. Help is provided, for example, by making a mark on the guide mandrel or on the spindle, which is then observed during machining and is allowed to move downwards by a predetermined amount. Because the feed must thereby be actively monitored and, on the other hand, it is technically possible to exceed the desired feed dimension, this method is fraught with uncertainties. Especially when several valve seats of the same cylinder head must be replaced, there is a risk that is not turned off by one unit ⁇ royal feed Mass. The used afterwards Valve seat rings or the valve seats rotated and reworked therein then vary in height from valve seat to valve seat.
• a device for determining and controlling the feed on a valve seat machining device which has a clampable, all-round pivotable swivel ball with a guide sleeve in which a spindle acting as a guide pin is rotatably and axially displaceably mounted , wherein below the guide sleeve, a chuck is provided, in which is clamped at an oblique angle to the spindle axis a turning tool, characterized by at Füh ⁇ approximately sleeve moveably held means which the spindle carry axially displaceable and adjusting means for determining and limiting the axial displaceability of the spindle in the direction of feed relative to the guide sleeve.
• the device therefore enables a reliable determination of the feed, at the same time defining a stop which ensures that the desired feed dimension cannot be overrun. Thanks to this device, several valve seats can be machined with exactly the same feed dimension, so that all combustion chambers experience exactly the same volume increase during machining and do not result in volumes that vary slightly so far. Such varying combustion chamber volumes otherwise have a disadvantageous effect, in particular in modern engines with high compressions and at the same time a small cubic capacity. If the total combustion chamber volume is not allowed to be increased overall, the cylinder head can be ground down by an amount that can be calculated according to the cylinder diameter and the valve diameter of the valves belonging to the machined seats to compensate for the increase in volume.
• FIG. 1 The valve seat processing device placed on an overturned cylinder head with the device according to the invention seen from the side before the valve seat processing;
• Figure 2 The device according to the invention on the valve seat processing device in a partial section along the axis of the spindle.
• FIG. 1 shows the elements of a valve seat processing device that are essential for understanding the invention.
• a device generally has a housing 27 through which the guide mandrel or the spindle 26 extends.
• the spindle 26 is rotatably mounted in a guide sleeve 1 and can be axially displaced therein over a certain range.
• the guide sleeve 1 passes in the interior of the housing 27 centrally through a swivel ball held there between two clamping rings.
• the spindle 26 can be rotated, displaced vertically and pivoted in relation to the housing 27 in all directions over a certain range.
• the spindle 26 has a chuck 28 with a fastening screw 29, in which a turning tool 30 can be clamped at an oblique angle to the axis of the spindle 26.
• the height of the housing 27 is seated on a bearing block (not shown) belonging to the device, which in turn has a magnet for 31.
• the cylinder head 33 to be machined is first overturned, so that the valve openings come to rest on top.
• the cylinder head 33 is clamped in this position on a processing station.
• the magnetic chuck 32 is clamped onto the cylinder head 33 in such a position with the cylinder head 33 that its surface assumes an identical position relative to each valve opening.
• valve seat processing device is now placed with its magnetic foot 31 on the magnetic clamping plate 32 with respect to the valve opening to be processed, its spindle 26 acting as a guide mandrel being inserted into the valve guide 34.
• the height of the turning tool 30 is adjusted by means of the adjusting screw 35 such that it comes to lie approximately one millimeter above the surface to be machined, as shown in FIG. 1.
• the spindle 26 is now centered in the valve guide 34.
• the play of the deliberately somewhat smaller dome is measured electronically over two intersecting directions and the mandrel is then moved into the calculated centering position by means of servomotors.
• centering is carried out by selecting a dome that is as free of play as possible.
• the guide sleeve 1 is clamped in the device by the clamping rings of the swivel ball clamping the latter and thus holding the guide sleeve 1 firmly in place. In this situation the device is in fi gur 1 shown.
• the size of the feed can now be determined, which also defines the end of the feed.
• the device has the device according to the invention for determining and checking the feed, which sits above the housing 27 of the device on the spindle, which at the same time acts as a guide pin.
• a scale 36 belongs to this device, which is attached to a thickening of the guide sleeve 1.
• the lower end of the thickening has a radially outwardly projecting edge 37, the upper side of which is intended to act as a stop.
• a vernier ring 6 with a scale which is engraved along its outer circumference is placed over the thickening.
• a setting sleeve 5 designed as a coupling sleeve with a knurled grip circumference is slipped over the vernier ring 6 and rotating therewith, and the feed nut 7, which can be rotated relative to the setting sleeve 5, can be seen above this setting sleeve 5.
• the feed nut 7 which can be rotated relative to the setting sleeve 5
• the feed nut 7 can be clamped with the adjusting sleeve 5.
• the feed nut 7 is rotated, as a result of which the spindle lowers. It is rotated until the turning tool 30 touches the surface to be machined on the spindle 26. This is the reference position of the turning tool 30.
• the adjusting sleeve 5 After loosening the retaining screws 15, the adjusting sleeve 5 is rotated, as a result of which the vernier ring 6 moves in the axial direction while rotating.
• a desired feed dimension can be set by reading from the lower edge of the ring 6 on the scale 36 on the thickening of the guide sleeve 1.
• the circumference of the vernier ring 6 has a scale from 1 to 100, the vernier ring 6 moving in the axial direction by one millimeter during a full revolution. The axial position can therefore be determined to within a hundredth of a millimeter.
• a valve seat for a valve seat ring with a thickness of 5.2 mm is to be turned out, this dimension of 5.2 mm must be set on the scale 36.
• the machining can now begin by turning the spindle 26 with the turning tool 30 as a spindle and the machining operation is continued with the turning tool 30 until the vernier ring 6 at the top of the lower edge 37 of the thickening finds a stop on the guide sleeve 1. If one does not know the thickness of a valve seat ring to be fitted, After the turning tool 30 is in contact with the surface to be machined and the feed device is presented as in FIG.
• the outside of the valve seat ring simply contacts the thickening 1 of the guide sleeve 1 between the upper side of the lower edge 37 and the lower edge of the vernier ring 6 are held.
• the adjusting screw 5 is then turned until the valve seat ring is clamped between the lower edge of the vernier ring 6 and the upper side of the lower edge 37 of the thickening 1 of the guide sleeve 1.
• the retaining screws 15 are tightened and the valve seat ring is pulled out of the jam.
• the correct size is now set and fixed.
• FIG. 2 shows the interior of the feed device in a partial section along the axis of the spindle 26.
• the spindle 26 passes through the housing 27 of the processing device. It is rotatably and axially displaceably mounted in a guide sleeve 1.
• This guide sleeve 1 is firmly seated in the swivel ball 17, which is mounted between two clamping rings 18, 19 and can be clamped between them.
• an O-ring 20 is inserted into the inside of the guide sleeve 1 so that the lubricant does not run out and no dust can penetrate between the spindle 26 and the guide sleeve 1.
• the swivel ball 17 can be braced against the upper housing plate by turning the clamping ring 14, the upper clamping ring 19 then being pressed against the bottom.
• the actual device for determining and checking the feed begins towards the top with a thickening 1 of the guide sleeve 1, which has an edge 37 at the lower end.
• the upper end of the guide sleeve 1 is given by the upper end of the thickening.
• this thickening has a thread on the outside, onto which a threaded sleeve 3 with an internal and external thread is screwed.
• On the top of the guide sleeve there are several axial blind holes 38 into which standard compression springs 21 are inserted.
• These standard compression springs 21 act on a threaded ring 2, which is screwed into the inside of the threaded sleeve 3 from above. This threaded ring 2 is secured against rotation with respect to the guide sleeve 1 by means of an axial bolt which cannot be seen.
• the purpose of these standard compression springs 21 is to avoid any play in the threaded connection between the guide sleeve 1 and the threaded sleeve 3, in that the thread is always under spring load. At the point to the right of the section of the threaded ring 2 in FIG.
• the spindle is tapered to a smaller diameter and an adapter 12 in the form of a sleeve sits on its upper end, which is screwed onto the spindle 26 by means of a hexagon screw 16.
• a screw 39 is screwed into the adapter 12, which rests on a chamfered point 40 of the spindle 26, whereby the torque can be transmitted from the adapter to the spindle 26.
• the adapter has a radially projecting cam 13 on its outside, which in turn serves to transmit the torque from a drive means to the adapter 12.
• the feed nut 7, which is knurled on the outside, is screwed onto the threaded sleeve 3 from above and secured thereon by means of a special glue.
• an intermediate ring 10 is also clamped, which serves for the axial transmission of force to the spindle 26.
• Axial bearings in the form of axial needle cages 22 are arranged above and below the intermediate ring 10. The lower one lies on the axial disk 23, which in turn rests on a shoulder formed by a taper on the spindle 26 and rotates with it.
• the axial bearing above the intermediate ring 10 is acted upon by an axial disk 24 which closes at the top and also rotates with the spindle 26 and on which finally there is a resilient cover disk 11 and a compensating disk 25, so that the axial bearings 22 because of the fastening of the adapter 12 by means of the screw 16 are always loaded by a spring force.
• the thread acts between the threaded sleeve 3 and the guide sleeve 1 when the guide sleeve 1 is tensioned, as a result of which the feed nut 7 with all the parts connected to it moves downward, for example.
• the spindle 26 does not have to rotate.
• the adjusting sleeve 5 is designed as a union sleeve and hangs with its upper inner edge in the secant grooves on the outer circumference of a plurality of bushes 8 distributed over the circumference, which in turn are axially attached by means of cylinder retaining screws 15 with a hexagon socket on the underside the feed nut 7 hang.
• cylinder retaining screws 15 By tightening the cylinder retaining screws 15 using an Allen key, the bushes 8 are pulled in the axial direction against the feed nut 7, as a result of which the adjusting sleeve 5 is clamped against the feed nut 7.
• the adjusting sleeve 5 is also provided with knurling.
• a fastening ring 4 is screwed onto the outside of the threaded sleeve 3, from which a pin 41 protrudes in the radial direction at the top.
• This pin .1 protrudes into a groove (not shown) which runs axially in the inside of the adjusting sleeve 5. If the adjusting sleeve 5 is rotated in the released state, it takes the pin 41 and thus the fastening ring 4 with it, which moves correspondingly up or down as a result of the thread connection with the threaded sleeve 3 relative to that and the guide sleeve 1.
• a vernier ring 6 is screwed onto the threaded sleeve 3, which is secured in its rotational position relative to the fastening ring 4 by a grub screw passing radially through the fastening ring 4, which acts on the vernier ring 6 from the outside.
• This grub screw is used to reset the scales during assembly.
• the vernier ring 6 has a scale from 1 to 100, which extends around its circumference.
• the external thread of the threaded sleeve 3 has such a pitch that one revolution of the vernier ring 6 rotating with it makes a feed of one millimeter. In the axial direction, a millimeter scale is then attached to the thickening 1 of the guide sleeve 1, which can be read at the lower edge of the vernier ring 6.
• the adjusting sleeve 5 When the screws 15 are loosened, the adjusting sleeve 5 is rotated, which thereby maintains its vertical position, but takes along the fastening ring 4 via the pin 41, which moves because of the threaded connection with the threaded sleeve 3 upwards or downwards relative to the latter.
• the nonius ring 6 is fastened to the fastening ring 4, which therefore also rotates and is correspondingly moved up or down.
• the vernier ring 6 can be adjusted by turning the adjusting sleeve 5.
• the distance between its lower edge and the top of the edge 37 on the thickening 1 of the guide sleeve defines the extent of the possible downward feed. This measure can be read from the thickening 1 using the scale attached there.
• the vernier ring 6 has a scale of 1 to 100 around its circumference and a full revolution makes a vertical movement of one millimeter, the feed dimension can be adjusted to a hundredth of a millimeter. Finally, at the end of the adjustment work for the feed, the cylinder retaining screws 15 are tightened, after which the valve seat processing device is ready for processing.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Turning (AREA)
• Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
• Paper (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=4243233

Family Applications (1)

Country Status (8)

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Family Cites Families (3)

• 1990
  • 1990-09-04 CH CH2861/90A patent/CH682097A5/de not_active IP Right Cessation
  • 1990-09-13 TW TW079107706A patent/TW203574B/zh active
• 1991
  • 1991-08-08 SK SK132492A patent/SK132492A3/sk unknown
  • 1991-08-08 PL PL29436991A patent/PL294369A1/xx unknown
  • 1991-08-08 AU AU82912/91A patent/AU8291291A/en not_active Abandoned
  • 1991-08-08 EP EP91913846A patent/EP0500827A1/de not_active Withdrawn
  • 1991-08-08 HU HU921453A patent/HUT62223A/hu unknown
  • 1991-08-08 WO PCT/CH1991/000165 patent/WO1992004152A1/de not_active Application Discontinuation

Non-Patent Citations (1)

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