Patent Publication Number: US-3877456-A

Title: Radiusing dressing apparatus

Description:
United States Patent [1 1 Druge et al.  
 [ Apr. 15, 1975 [22] Filed:  
 [ RADIUSING DRESSING APPARATUS [75] Inventors: Gerard Druge, Cran Gevrier; Rene LaCombe, Annecy, both of France [73] Assignee: Societe Anonyme dite: Societe Nouvelle de Roulements, Annecy, France May 13, 1974 [21] Appl. No.: 469,569  
 Primary Examiner-Harold D. Whitehead [57] ABSTRACT A radiusing dressing device adapted to dress the periphery of a grindstone to a part toroidal form. The device includes a spindle pivotable without backlash in an outer housing about a first axis, and means are provided for pivoting the spindle through a limited angle, in either sense, about said first axis. The outer housing is secured to a support via a first limiting chuck which is deformable in a first direction and has a high rigidity in a second direction perpendicular to said first direction, the spindle carrying at one end a right-angled diamond carrier through the intermediary of a second unitary chuck deformable in one direction and having a high rigidity in a perpendicular direction. Each of the chucks have a respective precision adjustment means adapted to place the respective chuck in tension and to deform it to provide, in the case of the first chuck, adjustment of the position, measured perpendicular to the first axis, of the first axis with respect to the support, and in the case of the second chuck, adjustment of the position of the diamond carrier with respect to the first axis.  
 8 Claims, 2 Drawing Figures PATENTEDAPR I 51975 SHEET 1 [IF 2 RADIUSING DRESSING APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a radiusing dressing or trussing device and more particularly to such a device which is a permanent attachment on a machine for grinding bearing races and enables a diamond to generate a toroidal shape on a grindstone.  
 2. Description of the Prior Art Radiusing dressing devices per se are well-known;  
  however, the prior art devices are generally disposed in front of the workpiece spindle and at right angles to the axis of such spindle. Further, most of the prior art devices are bulky and, being a fixture on the table or bed which bears such spindle, are bound to obstruct the working area. They usually take the form of a horizontal carrying block inside of which is disposed a system for adjusting to the grindstone diameter; this adjustment for the support is achieved by the bending of spring strips connecting the support to the bottom bedplate secured horizontally on the table, while a U- shaped support member rigidly secured to the front surface of the carrying block retains the pivoting part of the diamond carrier along a vertical axis.  
  The diamond carrier usually takes the form of a stirrup-Iike member in whose central part the diamond mount is rigidly secured, the stirrup-shaped member being pivotable through a desired adjustable angle in one direction in its outward movement and in the other direction in its return movement, the rotating part of the diamond carrier also comprising a bottom pivot, a top pivot and the drive for rotating such carrier.  
  The pivot at the bottom of the stirrup-shaped member comprises a self-aligning double row ball bearing and a carrying spindle secured to the bottom arm of the U-shaped carrier, and the top part of the stirrup-shaped member is connected to the base of the top pivot, which is rigidly secured to the other arm of the U- shaped carrier, by means of spring strips disposed before and behind the stirrup-shaped member. The same behaves like a lever articulated at its base, the movement of such member in its top part, for correction of the curvature of the grindstone periphery in axial section, being controlled by a ratio lever secured to the base of the top pivot, so that the system embodied by the stirrup-shaped member and the two pivots is not particularly rigid.  
  The curvature of the grindstone periphery in axial section is herein referred to for convenience as the radius of curvature of the grindstone; the distance from the periphery of the grindstone to its axis of rotation being simply referred to as the radius of the grindstone, and twice this distance as the diameter of the grindstone.  
  The provision ofa self-aligning bearing at the bottom of the stirrup-shaped member and of a ball bearing at the top impairs the accuracy with which the stirrupshaped member rotates. It is very difficult to protect the radius-of-curvature correction system, disposed as it is between the top of the stirrup-shaped member and the base of the top pivot and between the spring strips interconnecting the same, and so sealing-tightness is unsatisfactory and spray liquid and grinding sludge can readily enter the interior and upset satisfactory operation. Similar considerations apply to the grindstone diameter correction system which is disposed at the rear between the carrying block and the bedplate secured horizontally on the workpiece spindle table. Also, since there is no chance of tangential outlet with diamond carriers of the kind described, considerable space is taken up in the working zone and the workpiece spindle table has to be moved transversely during dressing, so that the table locating stops have to be arranged very accurately to position the table for each dressing.  
 SUMMARY OF THE INVENTION It is an object of the invention to obviate these disadvantages and provide a radiusing dressing device by means of which the periphery of a grindstone, for toroi&#39; dally profiling the inner raceway of the outer rings of ball bearings, can be dressed to a desired toroidal shape using a diamond, with correction for alteration in grindstone diameter and radius of curvature, and which can be made of reduced overall size compared with known devices and can be made retractable with respect to a grinding machine to which it is fitted in order to leave the working area completely clear.  
  According to the invention there is provided a radiusing dressing device adapted to dress the periphery of a grindstone to a part toroidal form. The device includes a spindle pivotable without backlash in an outer housing about a first axis, and means are provided for pivoting the spindle through a limited angle, in either sense. about said first axis. The outer housing is secured to a support via a first limiting chuck which is deformable in a first direction and has a high rigidity in a second direction perpendicular to said first direction, the spindle carrying at one end a right-angled diamond carrier through the intermediary of a second unitary chuck deformable in one direction and having a high rigidity in a perpendicular direction. Each of the chucks have a respective precision adjustment means adapted to place the respective chuck in tension and to deform it to provide, in the case of the first chuck, adjustment of the position, measured perpendicular to to the first axis, of the first axis with respect to the support, and in the case of the second chuck, adjustment of the position of the diamond carrier with respect to the first axis.  
  The arrangement and assembly of the various items which make up the dressing device according to the invention can readily, in association with gaskets, make the moving elements completely hermetic, so that spray liquid cannot infiltrate nor sludge enter and ensuring proper and accurate operation of the dressing device and of the strictly accurate adjustments necessary for dimensional drift and the radius of raceway curvature.  
 BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention is described below with reference to the accompanying drawings wherein:  
  FIG. 1 is a longitudinal section on the axis of rotation of an embodiment of radiusing dressing device according to the invention, and  
 FIG. 2 is a plan view on the line A-B.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings. the radiusing dressing device shown comprises a pivoting system, allowing the dressing diamond to be pivoted about an axis perpendicular to the rotary axis of the grindstone to be dressed, which is very rigid and very accurate since, as  
 shown in Flg. 1, it is embodied by a cylindrical housing or sleeve 1 and two high-precision angular contact ball bearings 2 which are disposed opposite one another and which are preloaded and which provide centering and rotation of a hollow shaft 3 free from all axial and radial backlash.  
  The device shown also comprises means for effecting such pivotal movement of the diamond, said means being in the form of a known hydraulic cylinder 4 secured to the back of the pivoting system. Any other mechanical means of effecting such pivotal movement may of course be used.  
  Cylinder 4 has a centering bush 5 which is rigidly secured to shaft 3, a moving quadrant 6 which serves as a piston and which is rigidly secured to bush 5 by means of a cylindrical pin 7 and of screws (not shown), a stationary quadrant 8 rigidly secured to cylinder casing 9 by means of a cylindrical pin 10 and of screws 11, and a front cover 12 and a rear cover 13 which close the cylinder 4 and enable the same to be centered on and secured to the pivoting system by means of screws 14 and provide sealing-tightness thanks to O-ring gaskets 15 associated with each cover.  
  Two limit stops 16, 17&#39; are secured to the back cover 13 in a symmetrical arrangement on either side of a half-circumference; depending upon their setting and in cooperation with a stop or abutment 18, the abutments 16, 17 limit the angle through which the dressing device can be pivoted, the abutment 18 being secured to a finger 19 secured to a sleeve 20 rigidly secured by keying to the hollow shaft 3, the stop 18 striking the stop 16 at the end of the operative movement of the device and striking the stop 17 at the end of the return movement. As the top part of finger 19 approaches proximity detectors 21, 22, visible in FIG. 2, the same operate electrovalves which allow pressurized oil to enter, or oil to leave freely, each of the chambers in cylinder 4 on either side of the sector 6 and sector 8.  
  The device shown also has provision for correcting the radius of grindstone curvature, i.e., the radius of curvature of the peripheral surface of the grindstone in a plane including the rotational axis of the grindstone. This provision is embodied by the cutting diamond being fitted and secured to the pivoting front part of the pivoting system by way of a unitary deformable chuck 26, while the fine adjustment mechanism for grindstone radius of curvature is disposed within such pivoting part and on the pivoting axis.  
  An intermediate bedplate 25, to the front part of which the unitary deformable chuck 26 is secured, is located on shaft 3 without backlash by a centering sleeve 23 which is centered in shaft 3, and is secured by means of screws 24.  
  Chuck 26, which is given an appropriate shape by being machined as a very wide parellelepiped so as to have high transverse rigidity, has a reduced thickness portion 26a interconnecting its two arms 26b, 26c. A right-angled carrier 27 for a diamond mount 28 is secured by screws 29 to the outer side surface of arm 26b, which is free and acts as a lever arm, while the unitary chuck 26 is secured by way of the other arm 26c, which acts as a mounting bedplate, to the intermediate bedplate by means of screws 30, an internal recess in bedplate 25 (provided for a purpose which will become apparent) thus being closed and therefore remaining hermetic.  
  For approximate adjustment of said radius of curvature, the carrier 27, guided by a key 30a secured to arm 26b, is shifted vertically as viewed in FIG. 1. The adjustment is facilitated by appropriate apertures (not shown) disposed near the screws 29. The fine adjusting mechanism and the mechanism for radius-of-curvature correction of the grindstone takes the form of a manually operated differential-pitch screw mechanism which enables the radius of curvature to be kept under tension and fine adjustment to be effected without backlash, by deformation of the chuck 26 by means of action on the end of a lever 34 and through the agency ofa stop 37 which is disposed on such lever near its pivotal axis and which transmits the slight movements caused by the mechanism.  
  The differential pitch screw mechanism disposed on the pivoting axis of shaft 3 includes a drive spindle 31 which at one end 31a is guided and engaged by a righthand external screwthread of pitch p in the front side part 3a of shaft 3, the other end 31b of spindle 31 being guided in the rear internal part 3b of shaft 3, end 31b being adapted to receive outside shaft part 3b a knurled knob 32 which is secured to end 31b by keying and is locked by a screw. The knob 32 serves for manual fine adjustment of said radius-of-curvature of the grindstone. A thrust spindle 33 has a central portion 33a which is guided in the front internal part 3a of shaft 3, a rear part 33b having a right-hand external screwthread of pitch p p engaged in a screwthread recess in drive spindle 31, and a front part 330 of which extends through the centering bush 23 and bears byway of its rounded end on the free end of lever 34.  
  Spindle 33 and bush 23 are prevented from rotating with respect to shaft 3 by a cylindrical pin 35 rigidly secured to the intermediate bedplate 25 and extending parallel with the axis of shaft 3 and offset with respect to the latter as is, through a corresponding offset bore in central portion 33a. The mechanism also comprises the lever 34 which is pivoted at one end on a bush 36 rigidly secured to bedplate 25, for pivoting about an axis extending in a direction perpendicular to the rotary axis of spindle 3 the free end 340 of lever 34 is at a distance L from its pivotal axis and is moved through a distance p p by the differential-pitch screw mechanism for a single revolution of the knurled knob 32; through the agency of a force-fitted stop 37 which is at a distance 1 or more from its rotational axis 36, lever 34 transmits a slight movement (p p) X l/L to an abutment 38 rigidly secured to arm 26b of chuck 26, which arm pivots and moves the diamond carrier 27 secured to it. The diamond therefore moves very slightly relatively to the rotational axis XY to make an accurate correction of the radius of curvature.  
  Being in tension, arm 26b continuously applies a thrust to stop 37 of lever 34 which in turn reacts on thrust spindle 33, thus obviating any possible backlash in the differential-pitch screw mechanism and making the chuck 26 effectively rigid during dressing of the grindstone since the tangential force of the grindstone as transmitted by the diamond during cutting and which force tends to pivot arm 26b counterclockwise in Flg. l, is resisted by positive abutment of components 26b, 38, 37, 34 and 33 and not merely by spring tension, so that the chuck 26 is not deformed.  
  The radius-of-curvature fine adjustment mechanism is protected against the entry of spray and sludge and swarf by the fitting of the arm 260 over the internal recess in bedplate and a system of gaskets 39-42 which ensure complete sealing-tightness of the interior 3a of the hollow shaft 3 and of the internal recess in the intermediate bedplate 25.  
  A ring 44 disposed on knob 32 and locked thereon by a screw 43 has a conical outside periphery 440 which is graduated in 25 divisions (see FIG. 2). each division corresponding to a 0.005 mm alteration in radius of curvature, and the bush 20 has a S-division graduation along a generatrix of its outer periphery (see FIG. 2), each division representing 0.125 mm.  
  The device shown also includes means for correcting for the reduction in diameter of the grindstone due to wear. To this end the sleeve 1 is fixed with respect to a support 46 by way of a unitary deformable chuck 45 and, disposed on support 46 and connected to the dressing device is a fine adjustment facility which, through the agency ofa differential-pitch screw mechanism, enables the chuck 45 to be placed in tension and accurate correction for change in the diameter of the grindstone to be made without backlash by deformation of the chuck 45, such deformation producing a slight transverse shift of the dressing device, more particularly of the rotational axis XY of the diamond and of the pivoting system relative to the grindstone rotational axis 0.  
  Chuck 45, which is shaped appropriately, as a result of machining a very wide parallelepiped, to have high transverse rigidity, has a reduce thickness deformable portion 45a interconnecting its two arms 45!), 45c; one arm, 45b which serves as a mounting bedplate, is engaged in a longitudinal locating groove in support 46 and is secured thereby by means of screws 47, while the arm 45c, which is longer than the arm 45b, has its end secured to support 46 by way of a shim 48 and screws 49 and therefore acts as a spring strip to which the easing 1 is secured by virture of the casing 9 being secured to the underside of arm 450.  
  The casing 9 is located against movement transversely of arm 450 by having its top part formed with a channel which receives the arm 45(&#39;, and is located against movement longitudinally of arm 45c by a key 50 the casing 9 is rigidly secured to arm 45c by means of screws 51 whose heads extend freely through holes in the arm 45b.  
  The differential pitch screw mechanism for grindstone diameter adjustment is disposed on an axis perpendicular to the axis XY and comprises a cylindrical sleeve 52 which extends through support 46 and is secured thereto by an outer collar or flange 52a by means of screws 53. Inside sleeve 52 is a drive spindle 54 whose front part, which has an external right-hand screwthread of pitch pl, screws into sleeve 52, being guided by its major diameter, while the rear part of spindle 54, such part being outside sleeve 52, is adapted to receive a knurled knob 55 which is fixed to rear part 54 by keying and by a clamping screw, the knob 55 serving for manual adjustment for dimensional drift. The mechanism also comprises a thrust spindle 56 comprising two parts 57 and 58 which are pivotally connected to one another by means of a cylindrical pivot pin 59 passing through appropriately shaped end portions of the parts 57, 58. The upper spindle part 57, which at its upper end has a right-hand screwthread of pitch p2 p1, is engaged in a screwthreaded recess in spindle 54, while the lower spindle part 58 has a screwthreaded lower end screwed into the cylindrical sleeve 1 of the pivoting system, thus connecting the casing l to the adjustment mechanism for grindstone diameter adjustment.  
  Thrust spindle 56, which is prevented from rotating by a cylindrical pin 60 rigidly secured to sleeve 52 and extending into a longitudinal slot in the spindle, conveniently provided by the hinge formation by means of which parts 57 and 38 are connected, is so located by pin 60 that the pin 59 interconnecting the two halfspindles 57, 58 is perpendicular to the diamond carrier rotational axis XY to give the necessary angular play to the spindle part 58 and thus make proper operation possible with no risk of the spindle 56 jamming. One rotation of the knob 55 causes the thrust spindle 56, which is at a distance L, from the axis of the deformable portion 45a of chuck 45, to move the adjacent part of casing l axially (with respect to spindle 54) by a reduced amount (pl p2); consequently, at the level of the diamond 28 which is at a distance L from the axis of the deformable part 45a of the chuck 45, the rotational axis XY of the pivoting system is shifted transversely by an amount (pl -p2) X L /L relatively to the grindstone rotational axis 0, thus providing accurate correction for grindstone diameter.  
  Chuck 45 is placed in tension by the grindstone diameter correction mechanism acting on the part of the device secured to the chuck arm 450 in such a way that chuck 45 places spindle 56 in tension rather than in compression, thus obviating any backlash in the differ ential pitch screw mechanism and providing extra longitudinal stiffening for the chuck 45; the same cannot therefore be deformed by the tangential force of the grindstone, such force being transmitted to the dressing device by the diamond 28 during cutting.  
 The grindstone diameter correction mechanism is protected against the entry of spray liquid and swarf and sludge by the provision of O-ring gaskets 61, 62 which seal off the inside of cylinder 52. A ring 64 secured to knob 55 and locked by a screw 63 has a conical outer periphery 64a graduated in 42 divisions each corresponding to a 0.0l mm advance or return of the diamond relatively to the grindstone rotational axis; the outer collar 52a has a 3-division graduation marked along a generatrix of its outer periphery each division representing 0.42 mm.  
  For approximate adjustment of grindstone diameter, the support 46 is moved transversely (i.e., vertically in FIG. 1) relative to the grindstone rotational axis. This approximate adjustment is made with the help of an adjustable stop on the machine.  
  Manual operation of the facilities for radius-ofcurvature adjustment and grindstone diameter correction can be replaced by an automatic facility using a ratchet wheel or stepby-step motor or any other known means.  
  In the grinding machine to which the device described is fitted, the support 46, is mounted for pivoting with respect to the remainder of the machine, in a backlash free manner, or is fitted to a slideway free from backlash, for sliding with respect to the remainder of the machine, so that the device can be retracted, between dressing operations, to leave the working area in which a bearing race is being ground, completely clear.  
 We claim:  
  1. A radiusing dressing device of the type employed to dress the periphery of a grindstone to a part toroidal form, and comprising a support, an outer housing. a  
 spindle, means mounting said spindle for pivotal movement about its longitudinal axis without backlash within said housing, means for pivoting said spindle through a limited angle. in either sense, about said longitudinal axis, a first unitary chuck mounting said outer housing on said support, said first chuck being deformable in a first direction and having a high rigidity in a second direction perpendicular to said first direction, a second unitary chuck mounted on one end of said spindle and supporting a right-angled diamond carrier. said second chuck being deformable in one direction and having a high rigidity in a perpendicular direction, each of said chucks having a respective precision adjustment means adapted to place the respective chuck in tension and to deform it to provide, in the case of said first chuck, adjustment of the position measured substantially perpendicular to said longitudinal axis of said longitudinal axis with respect to said support and in the case of said second chuck adjustment of the position of said diamond carrier with respect to said longitudinal axis.  
  2. A dressing device according to claim 1, wherein said means for pivoting said spindle comprises a rotatable hydraulic motor including a cylinder rigidly secured to said outer housing and a segmental piston rigidly secured to the spindle.  
  3. A dressing device according to claim 1 wherein said precision adjustment means associated with said first chuck comprises a differential pitch screw acting between said outer housing and said support in a direction substantially perpendicular to said longitudinal axis.  
  4. A dressing device according to claim 1, wherein said precision adjustment means associated with said second chuck comprises a differential pitch screw coaxial with said spindle, which to this end is hollow.  
  5. The dressing device as defined in claim 4 wherein said diamond carrier is mounted on a movable arm of said second chuck, said device further comprising a pivotally mounted lever interposed between said differential pitch screw and said arm to transmit movement of said differential pitch screw to said arm.  
  6. The dressing device as defined in claim ,5 wherein said precision adjustment means associated with said first chuck comprises a differential pitch screw acting between said outer housing and said support in a direction substantially perpendicular to said longitudinal axis.  
  7. The dressing device as defined in claim 6 wherein said means for pivoting said spindle comprises a rotatable hydraulic motor including a cylinder rigidly secured to said outer housing and a segmental piston rigidly secured to the spindle.  
 8. A dressing device according to claim 7 in which&#39; the precision adjustment means are hermetically