US2839875A - Machine for the grinding of cylindrical, conical and crowned spur gears and helical gears by the generating principle - Google Patents

Description

June 24, 1958 ,A. RICKENMANN' 2,839,875

, MACHINE FOR THE GRINDING 0F CYLINDRICAL. CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE 18 Sheets-Sheet 1 Filed Sept. 17. 1956 rllll h lamnumun nmr June 24, 1958 A. RICKENMANN 2,839,875

MACHINE FOR THE GRINDING OF CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE 18 Sheets-Sheet 2 Filed Sept. 17, 1956 10" 1431 I b 1''; Q 7. b .g} 1411 0 W 14 b 'I' bl June 24, 1958 A. RICKENMANN 2,339,875

MACHINE FOR THE GRINDING 0F CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE Filed Sept. 17; 1956 18 Sheets-Sheet 3 b%\ as m m R w. m & 0 Nv m \mN Qo 4 Rm mm. E mu s mmv NQQE -3Svwmw 5 3w x N Ow w MM w jw N R m a m m w .m u 3 w k 1 NV k 3% && U mv a a w J m 3 W T N m Gm km June 24, 1958 A. RICKENMANN 2,839,875

MACHINE FOR THE GRINDING OF CYLINDRICAL,CONICAL 7 AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE Filed Sept. 17, 1956 18 Sheets-Sheet 4 June 24, 1958 A. RICKENMANN 2,339,875

MACHINE FOR THE GRINDING OF CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY; 7

1 THE GENERATING PRINCIPLE v 18 Sheets-Sheet 5 Filed Sept. 17, 1956 [L I I 128 L m IIlIIlIII/I 2,839,875 CAL, CONICAL June 1958 A. RICKENMANN v MACHINE FOR THE GRINDING 0F CYLINDRI AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE 18 Sheets-Sheet 6 Filed Sept. 17, 1956 A. RICIKENMANN June 24, 1958 2,839,875

MACHINE FOR THE GRINDING 0F CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE 18 Sheets-Sheet 7 Filed Sept. 17, 1956 Nil 11111624, 1958 A. RICKENMANN 2,83

MACHINE FOR THE GRINDING OF CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE Filed Sept. 17, 1956 18 Sheets-Sheet 8 June 24, 1958 A. RICKENMANN 2,839,875

MACHINE FOR THE GRINDING 0F CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE 7 Filed Sept. 17, 1956 18 Sheets-Sheet 9 June 24, 1958 A. RICKENMANN 2,839,875

MACHINE FOR THE GRINDING'OF CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE Filed Sept. 17. 1956 18 Sheets-Sheet Fig.3a

.16 93/ Y 1 0 5 up 983 1 9 2 0 June 24, 1958 A. RICKENMANN 2, MACHINE FOR THE GRINDING 0F CYLINDRICAL, CQNICAL AND cRowNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE Filed Sept. 17, 1956 18 Sheets-Sheet 11 Fig. 9b

June 24, 1958 A. RICKENMANN 2,839,875

MACHINE FOR THE GRINDING OF CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE Filed Sept. 1'7, 1956 18 Sheets-Sheet 12 June 24, 1958 A. 'RICKENMANN 2,339,875

MACHINE FOR THE GRINDING 0F CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE 18 Sheets-Sheet 13 Filed Sept. 17, 1956 I 7///47A//A//////////47////// June 24,1958 A. RICKENMANN 2,839,875

MACHINE FOR THE GRINDING OF CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE Filed Sept. 1'7, 1956 I 18 Sheets-Sheet 14 Fig. 101:

June 24, 1958 A. RICKENMANN 2,839,875 MACHINE FOR THE GRINDING 0F CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE Filed Sept. 17, 1956 18 sheets-sheet 15 Fig. 70c

June 24, 1958 A. RICKENMANN 2,839,875

7 MACHINE FOR THE GRINDING 0F CYLINDRICAL. CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE j 18 Sheets-Sheet 16 Filed Sept. 17, 1956 Fig. 710

June 24, 1 A. RICKENMANN ,83

MACHINE FOR THE GRINDING OF CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE Filed Sept. 17, 1956 18 Sheets-Sheet 17 Filed Sept. 17, 1956 June 24, 1958 A. RICKENMANN 2,839,875

MACHINE FOR THE GRINDING 0F CYLINDRICAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL' GEARS BY THE GENERATING PRINCIPLE v l8 Sheets-Sheet 18 .ls1 52 i United States Patent Qfilice 2,839,875 Patented June 24, 1958 MACHINE FOR THE GRINDING OF CYLINDRI- CAL, CONICAL AND CROWNED SPUR GEARS AND HELICAL GEARS BY THE GENERATING PRINCIPLE Alfred Rickenmann, Kusnaclrt, near Zurich, Switzerland,

assignor to Reishauer-Werkzeuge A. G., Zurich, Switzerland Application September 17, 1956, Serial No. 610,262

Claims priority, application Switzerland November 18, 1955 3 Claims. (Cl. 51--95) The present invention relates to devices in gear grinding machines operating on the generating principle which permits the grinding of gears having a non-cylindrical circumferential surface. Two different groups of work pieces fall under the term of gears having a non-cylindrical circumferential surface: the first group includes gears in which the toothing is arranged on the circumferential surface of a cone. To this group belong for example pinion type gear cutters which find use as cutting tools in gear shaping machines. Moreover in textile and book printing machines conical gears are fitted in order to compensate for differences in axial spacing. To the second group belong all those gears which have to be produced barrel-shaped or crowned as regards the direction of their. teeth. For the following considerations it is absolutely immaterial whether the crowning extends over the full width or over some sections only of the teeth to be ground.

The field of application of the invention extends to spur gears and helical gears. It moreover extends to work pieces the toothing of which is either already pre-m-achined and has merely to be finished by grinding on the gear grinding machine, or which may be produced directly from the solid.

On gear grinding machines operating on the generat ing principle hitherto only gears having a cylindrical circumferential surface could be ground. With the known embodiments of such devices the forcibly driven work piece is rotatably guided on a slide between two centre points; The said slide is arranged for translational movement in the direction of the axis of rotation of the work piece. When grinding the work piece the same is shifted past the grinding worm in order that each point of the width of the teeth comes into contact therewith and is ground thereby. When grinding gears having a cylindrical circumferential surface the axial distance between the work piece and the grinding worm remains the same over the whole width of the work piece to be machined. A feature in the production of non-cylindrical gears 'which hitherto could not be ground on gear grinding machines operating on the generating principle-consists however in that during the working process the distance between the axes of the tool and of the work piece is varied in accordance with the particular geometrical shape of the latter.

These variations in the distance between the axes may amount in conical gearsdepending on their widthto several millimetres. In contrast thereto in crowned gears deviations from the theoretical direction of the teeth are required which are of the order of magnitude of a few microns only.

Devices are known on several other types of gear machining machine tools which permit the production of conical gears or of crowned tooth shapes. These devices have the object to effect the variations in the distance between the axes of the work piece and the tool.

The means coming into action for this purpose have hitherto been entirely different from one another depend ing on whether they were used for the production of conical gears or of crowned teeth. The choice of the means and/or the structural arrangement of the devices where determined exclusively by the magnitude of the variations of the distance between the axes. Accordingly different types of machine tools had to be brought into action for performing one or the other machining operation.

In one known embodiment of a machine for the grinding of conical gears the work piece to be ground is rotatably mounted about a horizontal axis. A single rib grindingwheel is mounted on a slide, the guide ways of which are disposed at a slope. Their gradient corresponds to the cone of the toothing to be ground. During the grinding process the work piece is restrained in its axial position while the slide carrying the grinding wheel is moved to-and-fro. The disadvantage of this construction consists in that adjustable guide ways are required in order that the same may be adjusted to the varying requirements as'regards conicity. This arrangement may be convenient for single-purpose machines i. e. where continually work pieces with the same conicity are to be ground. In another known type of machines for the grinding of conical gears a feeder movement is imparted to the work piece during the grinding process in the direction of its axis of rotation. For this'purpose a threaded spindle is provided which is driven through change gears From this infeed mechanism a second threaded spindle is drivenlikewise through change gears. This second spindle is in engagement with a nut which is fixed on the slidably mounted grinding slide, and has the object of effecting the variation of the distance between the axis of the workpiece and the grinding wheel associated with the feeder movement of the workpiece, by altering the position of the grinding slide. 7

The devices described are unsuitable for theproduction of crowned gears, since with the means referred to it is not possible to attain the infinitesimal variations in the distance of the axes required. Forexample the lost motion in those components of the transmission which produce the variations in the axial distances required when grinding conical work pieces, are substantially larger than the variations in axial distance required when grinding crowned toothings. Crowned teeth could be produced hitherto on gear shaving machines. During the shaving process the work piece is not driven by a gear train at a quite definite speed but is set in rotation by the shaving tool. Owing to these driving conditions it is possible to impart to the work piece carrier an effective rocking movement with respect to the longitudinal axis during the shaving process. This movement is controlled by the aid of cam discs and linkages. These means are out of question for the'production of conical gears. 7

When grinding a gear by the generating principle the grinding worm and the work piece are driven separately. In these circumstances the means suitable for shaving are not applicable for the production of crowned gears, since a rocking movement of the work piece carrier is unthinkable owing to the presence and necessity of driving members.

Accordingly other new means and ways had to be searched for, in order to grind on a gear grinding machine operating on the generating principle the two aforesaid groups of gears having non-cylindrical circumferential surfaces. r

The following description with accompanying drawings discloses a novel inventive solution for carrying out the program desired.

The idea of the invention consists in that it is made .5 possible to carry out the grinding process on conical gears as well as of crowned gears on a gear grinding machine operating on the generating principle, by the aid of a single control element, although the variations in axial distances required therefor during the grinding process differ extremely from one another in their order of mag nitude. On the machine under consideration, constructed according to the invention the work piece is likewise carried by a slide, which is arranged slidably in the direction of the axis of rotation of the work piece.

The main feature of the invention is formed by a template adjustably mounted on the aforesaid slide and acting on a hydraulic control system which controls and influences the device serving for the variation of the distance between the axes of the work piece and of the grinding worm.

The control system governed by the said template of the machine constructed according to the invention comprises two hydraulic copying systems. One of them is in operation when grinding conical gears in order to carry out the necessary variations in the distance of the axes by altering the position of the grinder slide. The other one serves for generating the infinitesimal differences in the axial, distance when grinding crowned gears, by means of rocking movements, under the assumption that the work piece is continuously forcibly driven.

The applicability of the invention is not limited to machines in which the work piece is fed along its axis of rotation during the grinding process. It is quite possible to construct the machine in such a manner that the work piece maintains its axial position during the grinding while on the other hand the grinding worm is moved along the axis of the work piece. In this case the aforesaid control template would have to be mounted on the movable grinding slide. The functions and eifects of the control system governed by it remain, however, exactly the same. In connection with these considerations it has to be mentioned moreover, that the devices serving for the variation of the distance between the axes can for example be applied in such a manner that the grinding slide keeps stationary when grinding conical gears while. the adjustment movement is performed from the opposite side. It is likewise possible when grinding crowned gears to carry out the rocking movements on the side of the grinding worm instead of on the side of the work piece.

An embodiment of the subject of the invention will be described hereinafter with reference to the drawings, in which:

Fig. 1 is a frontal. view of the machine (composed of two parts 1a and 1b),

Fig. 2 is a longitudinal section of the drive of the work piece and the infeed mechanism for the grinding slide,

'Fig. 3 is a side elevation of the machine as seen from the left hand side,

Fig. 4 is a cross section of the machine on the line II of Fig. 1,

Fig. 5 shows part of the drive of the-work piece in section, as a modification of Fig. 2,

Fig. 6 shows a detailof the infeed mechanism of the grinding slide, partly in section on the line IIII of Fig. l,

Fig. 7 is a detail of the control partly in section on the line IIIIII of Fig. 1,

Figs. 8 to 11 (each divided into three parts a, b, c, respectively) diagrammatically show the hydraulic and electrical control means in various phases of operation,

Fig. 12 shows details of'the hydraulic control devices, partly in section on the line IV-IV of'Fig. 1,

Figs. 13 to 15 show developments of the rotary slide valves shown in Fig. 12,

Fig. 16 is a diagrammatic illustration of the. electric control means,

4 Fig. 17 shows a detail of the control mechanism, and Fig. 18 shows a work piece.

STRUCTURAL ARRANGEMENT OF THE MACHINE On the base 1 a support 2 is mounted pivotally. On the latter a guide rail 33 of semi-circular profile is attached by means of screws 34. It forms at the same time a fulcrum axis X and runs parallel to the axis of the grinding spindle. The accurate position of the support 2 is determined by a disc 35, which is fixed eccentrically on a shaft 36 at the right hand side of the machine (see Fig. 2), and which bears on the foot portion 29.1. This eccentrically mounted disc 35, its shaft 36 and a lever 37 fixed thereon form part of a control aggregate which will be described later in detail. In the support 2 a drum 3 is journalled which carries the work piece carrier slide 4 which is slidably arranged thereon. On the drum 3 a worm wheel segment 5 is fixed. The associated worm 6 is mounted on a shaft 7 (Fig. 4) journalled in the support 2, which can be turned by means of a hand wheel 8. This device serves for turning the drum 3 and the work piece holder slide 5 into an angular position which depends on the angular helix angle of the grinding worm 9 as well as on the helix angle of the work piece when grinding helical gears. The angular position of the drum 3 and of the work piece slide 4 can be fixed by the aid of screws 11. For the driving of the work pieces a motor 12 is provided-in the present case a synchronous motorwhich is fixed to the drum 3. in a bore of the drum 3 the rotatably mounted cage 13 of a difierential gearing is centered coaxially to the axis of the aforesaid motor. This cage 13 is locked when grinding spur gears. On the shaft end of the motor 12 a pinion 14 is mounted which is in mesh with a spur gear 15. The latter is mounted on a shaft 16 which is rotatably journalled in the cage 13 and is provided with a further spur gear 17. The latter is in mesh with a spur gear 18 which transmits rotary motion through the shaft 19 and the change gears 20, 21, 22, 23 on to the pinion 24. The four change gears are selected and fitted in accordance With the number of teeth of the work piece. The pinion 24 is rotatably journalled in two bores of the drum 3.

A spur gear 25 in mesh with the pinion 24 is keyed on a driving shaft 26 rotatably mounted in the work piece carrier slide 4. This shaft carries a further spur gear 27 which in turn meshes with a spur gear 29 mounted on the working spindle 255. The rotary movements of the working spindle 28 are transmitted by the aid of a dog to the mandrel 30 and to the work piece mounted thereon. The mandrel 30 is centered between the centre point of the Working spindle 28 and the centre point of the tail stock sleeve 31. As mentioned hereinabove the cage 13 of the differential gearing is kept at a standstill when grinding spur gears. A toothing 1311 (Fig. 5) provided on the said cage 13 is in mesh with a spur gear 42 which is keyed to a rotatably journalled shaft 43 together with a bevel gear 44. The bevel gear 44 meshes with a bevel gear 45 which is mounted on a shaft 46. On the end of the shaft pointing away from the bevel gear 4-5 a disc 47 is mounted (see Fig. 2). The latter is provided with a pin 48 projecting into a bore 391 provided in the drum 3. By this measure the cage 13, the spur gear 42, the shaft 43 the pair of bevel gears 44, 45 and the shaft 46 are locked.

When grinding helical gears an additional rotary movement has to be imparted to the work piece which is effected with the aid of the differential gearing by turning the cage 13. For this purpose the disc 47 designed for locking the said cage 13 is removed, and a spur gear 4 is fitted to the shaft end concerned (Pig. 5). The spur gear 49 together with three further spur gears 59, 51, 52 forms a train of change gears, which is determined in accordance with the helix angle to be produced on the work piece. The change gear 52 is mounted on a shaft

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