Apparatus for grinding bevel- or hyperboloid-shaped gears
United States Patent 11 1 Kotthaus [451 Apr. 15, 1975 APPARATUS FOR GRINDING BEVEL- OR HYPERBOLOID-SHAPED GEARS [75] Inventor: Erich Kotthaus, Kloten, Switzerland [73] Assignee: Werkzeugmaschinenfabrik Oerlikan-Buhrle AG, Zurich, Switzerland 221 Filed: Jan. 2, 1974 21 Appl. No: 429,519  
 Related US. Application Data [62] Division of Ser. No. 297,986, Oct. 16, l972.  
 [30] Foreign Application Priority Data Oct. 21, 1971 Switzerland l5375/7l [52] US. Cl. 51/90; 51/94 GH [51] Int. Cl B24b 3/00; B24b 5/00 [58] Field of Search 51/96, 287, 95 GH; 90/5 [56] References Cited UNITED STATES PATENTS 1,243,767 l0/l917 Schurr et al. 51/90 3,503,301 3/1970 Cantrell 90/5 Primary Examiner-Othell M. Simpson Attorney, Agent, or FirmWerner W. Kleeman [57] ABSTRACT An apparatus for grinding bevelor hyperboloidshaped gears having lengthwise curved teeth comprising a number of grinding bodies which are rotatably mounted about their axis at a circle at a grinding wheel or head, and wherein the grinding wheel is rotatable about an axis containing the center of the aforesaid circle. Drive means serve for the rotation of the grinding bodies.  
 8 Claims, 3 Drawing Figures APPARATUS FOR GRINDING BEVEL- OR HYPERBOLOID-SHAPED GEARS CROSS-REFERENCE TO RELATED CASE This is a divisional application of my copending commonly assigned US. application Ser. No. 297,986, filed Oct. 16, I972.  
 BACKGROUND OF THE INVENTION The present invention relates to a new and improved apparatus for grinding bevelor hyperboloidshaped gears with lengthwise curved teeth with the aid of a grinding body rotating about its axis.  
  According to a known prior art technique of this type bevelor hyperboloidshaped gears are ground in that there is employed a single grinding disk. wherein during an indexing type method technique one tooth gap after the other must be ground.  
 SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a new and improved apparatus by means of which it is possible to continuously grind all of the tooth spaces or gaps.  
  The method aspects of this development are characterized by the features that the axis ofthe grinding body moves within a tooth gap and continuously along an endless path.  
 The apparatus for the performance of the aforesaid method is manifested by the features that a number of grinding bodies are mounted to be rotatable about their axis at a circle at the grinding wheel, that the grinding wheel is rotatable about an axis containing the center of the aforesaid circle and is provided with a drive for rotating the grinding bodies.  
 BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:  
  FIG. 1 is a longitudinal sectional view through a grinding wheel or head of the inventive apparatus;  
  FIG. 2 is a top view of the grinding wheel of FIG. 1; and  
  FIG. 3 illustrates a machine employing the grinding wheel illustrated in FIGS. 1 and 2 for grinding bevelor hyperboloid gears.  
 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now the drawings, it will be understood that a grinding wheel or head possesses ll grinding bodies 11 arranged along an outer circle having a radius Ka and eleven grinding bodies 12 arranged along an inner circle having the radius K,-. As best seen by referring to FIG. 2 different angular spacings prevail between these grinding bodies 11 and I2, and specifically there are provided a smaller angular spacing 4J and a larger angular spacing (b so that there are formed groups of two respective grinding bodies 11 and 12 which respectively engage in a tooth gap or space ofthe gear to be ground. The grinding bodies 11 can be employed for grinding the convex tooth flanks and the grinding bodies 12 for grinding the concave tooth flanks. Further, the axis of each of the grinding bodies is rooled along a curve corresponding to the directrix of the associated gear tooth.  
  According to the showing of FIG. 1 the grinding wheel or head 10 possesses a base body 13 having a conical bore 14 by means of which this grinding wheel 10 can be secured to a nonillustrated work spindle. To this base body 13 there is attached a retaining or holder ring 15 with screws 16. The eleven inner grinding bodies 12 are secured to this retaining ring 15. Further, there are directly secured to the base body 13 the outer grinding bodies 11. As willbe more fully explained, both the inner and outer grinding bodies 11 and 12 are radially displaceable. For this purpose there is provided for each inner grinding body 12 a holder or support 17 which is radially displaceably supported at the retaining ring 15. With the aid of an adjustment screw 18 the holder 17 can be displaced in radial direction, and with the aid of a fixing screw 19 it can be fixed in desired position. In order to ensure that the holder 17 does not undesirably shift when the fixing screw 19 is released there is provided a blade spring 20. Further, two blade springs 21 are secured at each holder 17, between which there is mounted an inner grinding body 12. In analogous fashion the outer grinding bodies 11 are displaceable at holders or supports 22 at the base body 13. The holder 22 is displaceable in radial direction with the aid of an adjustment screw 23 and can be fixed in desired position with the aid ofa fixing screw 24. Here also a blade spring 25 secures the holder 22 against any unintentional displacement when the fixing screw 24 is released. At each holder 22 there are secured two blade springs 26, between which there is rotatably mounted an outer grinding body 11.  
  To adjust the angular spacing d), and 41 the retaining ring 15 is rotatably secured to base body 13. To rotate the retaining ring 15 upon the base body 13 it is sufficient to release the screws 16.  
  The grinding bodies 11 and 12 are composed of a conical tip and 12a and a cylindrical portion 11b and 1212 respectively. Such outer grinding bodies 11 are seated upon a spindle 27, the rear end face 28 of which is arched or domed. This end face 28 bears upon a first ring-shaped control disk or cam 29. This first control disk 29 is secured at housing 30, in which is mounted the nonillustrated work spindle, and does not rotate together with the grinding wheel or head 10. In analogous manner the inner grinding bodies 12 also bear upon a second ring-shaped control disk or cam 31. The second control disk 31 is secured in any suitable and therefore not particularly illustrated fashion at the first control disk 29. With the aid of such control disks 29, 31 the inner and outer grinding bodies 11, 12 can be displaced in axial direction while bending through the blade springs 21 and 26 respectively. Both control disks 29 and 31 are suitably adjustable secured to the housing 30.  
  Both the inner and the outer grinding bodies 11 and 12 are rotatable about their own axis and are driven pneumatically. For this purpose each grinding body 11, I2 is provided with a pneumatic drive motor 32, which has not been particularly illustrated in the drawing since it can be of conventional design. A compressed air conduit or line 33 leads to each drive motor 32, the compressed air conduit 33 being attached to the base body 13. A channel 34 is provided at the base body 13 for each compressed air conduit 33. All of the channels 34 open into a ring-shaped compartment 35 at the inte- 3 rior of a stationary grinding ring 36. The ring-shaped compartment 35 is connected through the agency of a hose 37, secured to the grinding ring 36, with a nonillustrated compressed air source.  
  The grinding wheel or head described in conjunction with FIGS. 1 and 2 is employed in a machine known as such in the art and generally illustrated in FIG. 3. This machine embodies a V-belt 7AM driven by a non-illustrated motor. This motor drives the grinding wheel or head 10 through the agency of the aforementioned V-belt as well as through the agency of a transmission A. Transmission A renders possible switching to four different speeds. Further, this transmission A possesses four change gears A1, A2, A3, A4, so that the grinding wheel can be driven at eight different rotational speeds. At the gears designated by reference character B there is provided an intermediate gear 6A2, by means of which the direction of rotation of the grinding wheel can be reversed. This renders possible the grinding of hyperboloid gears. The shaft 3A1, at which there is secured the grinding wheel 10, can be inclined with regard to the shaft 4A2. For each inclination the gears designated by reference character C must be exchanged. Owing to this inclination there also can be ground a very flat gear without the grinding bodies contacting the gear at its path when they move in front of and past the teeth of the gear to be ground. At the shaft 1T2 there is secured the gear to be ground. This shaft 1T2 is driven by a differential gearing of differential transmission D through the agency of different change gears T1, T2, T3, T4 as well as via the shafts 7T1, 7T2, 7T3 and 2T1. A roller drum 40, at which is located the grinding wheel 10, is driven by an endless worm 6W1. This worm 6W1 is connected with a transmission box S rendering possible changeover to 18 different speeds. The movement of the roller drum is transmitted with the desired transmission ratio to a satellite support of the differential transmission D. Between the transmission box S and the differential transmission D there are arranged change gears W1 to W6. An auxiliary motor E is provided for the purpose of rapidly moving the roller drum back into its starting position.  
  The mode of operation of the described apparatus is as follows: at the machine depicted in FIG. 3 there are produced the gears which are to be ground with the aid of the inventive apparatus. For this purpose there is mounted at this machine instead of the grinding wheel 10 a cutter head or tooth cutter which has not been illustrated in the drawing. The cutting operation occurs in a manner well known to those skilled in the art and therefore is not here further explained, expecially since details of the cutting operation do not constitute subject matter of this invention. The gear produced in the conventional manner upon the machine depicted in FIG. 3 now can be ground in that there is mounted at the machine, instead of the cutter head, the grinding wheel or head 10. For grinding the gear the machine is placed into operation in the same manner as during cutting of the gear.  
  For crown or camber grinding of the gears there are employed the control disks 29 and 31 which render possible axial displacement of the grinding bodies 11 and 12. Owing to this axial displacement of the grinding bodies 11 and 12 the gear can be ground in crowned or cambered manner in the desired way. In order to be able to change the load bearing surface of the tooth flank it is necessary to alter the position of the control disks. This can occur either solely by adjusting the control disks 29, 31 at the housing 30 or by exchanging such control disks 29, 31 for control disks of a different shape or configuration.  
  While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. Accordingly,  
 What is claimed is:  
  1. An apparatus for grinding bevelor hyperboloid gears possessing concave tooth flanks and convex tooth flanks, comprising a grinding wheel, a plurality of grinding bodies provided on the grinding wheel, a first group of said plurality of grinding bodies serving for grinding the concave tooth flanks of the gear and the remaining group of said plurality of grinding bodies serving for grinding the convex tooth flanks of the gear, means for mounting said first group of grinding bodies to be rotatable about their own associated axis at an inner circle at the grinding wheel, means for mounting the remaining group of grinding bodies to be rotatable about their own associated axis at an outer circle at the grinding wheel, means for mounting the grinding wheel to be rotatable about an axis containing the center of each said inner and outer circles, and drive means for rotating said grinding bodies.  
  2. The apparatus as defined in claim 1, further including means for mounting and rotating said grinding wheel such that its axis containing the center of said inner and outer circles revolves about a stationary axis.  
  3. The apparatus as defined in claim 1, further including adjustment means provided for the grinding wheel for positionally displacing the grinding bodies.  
  4. The apparatus as defined in claim 3, wherein said mounting means for each grinding body comprises a pair of flexible blade springs between which the associated grinding body is resiliently mounted in axial direction for camber grinding of the teeth of the gear, holder means for each grinding body adjustable radially with respect to the axis of the grinding wheel and forming the adjustment means for each grinding body, both of said blade springs being secured to its associated holder means.  
  5. The apparatus as defined in claim 3, wherein each grinding body possesses a spindle, exchangeable control disk means arranged substantially coaxially with respect to the grinding wheel against which resiliently bear the spindles of the grinding bodies and during relative movement between the control disk means and the grinding wheel said spindles are axially displaceable.  
  6. The apparatus as defined in claim 5, wherein said control disk means embody two independent control disks, one of the control disks being associated with the grinding bodies for the concave tooth flanks and the other control disk being associated with the grinding bodies for the convex tooth flank.  
  7. The apparatus as defined in claim 6, wherein said control disk means are adjustable for altering the load bearing surface at the tooth flank.  
  8. The apparatus as defined in claim 1, further including a retaining ring provided for said grinding wheel for accommodating the grinding bodies for the concave tooth flanks and a base body for accommodating the grinding bodies for the convex tooth flank, and means for mounting said retaining ring to be relatively rotatable with respect to the base body.