US2836014A

US2836014A - Machines for grinding gear tooth and like profiles

Info

Publication number: US2836014A
Application number: US362451A
Authority: US
Inventors: Calderwood Thomas Ethelred
Original assignee: WE Sykes Ltd
Current assignee: WE Sykes Ltd
Priority date: 1952-06-18
Filing date: 1953-06-18
Publication date: 1958-05-27
Anticipated expiration: 1975-05-27

Description

May 27, 1958 'r. E. CALDERWOOD 2,335,014

I HACHINES FOR GRINDING GEAR TOQTH AND LIKE PROFILES Filed June 18, 1953 2 Sheets-Sheet 1 Y X A Q1/1420. J I M 1 I vK z/ wum . m I l um mu NW y 1953 T. E. CALDERWOQD 2,836,014

MACHINES FUR GRINDING GEAR TOOTH AND LIKE PROFILES Filed June 18, 1953 2 Sheets-Sheet 2 r I. V. 22% mm Y X A. a

PAACHEIEE FOR GRINDING GEAR TOOTH AND LIKE PROFILES Thomas Ethelred Calderwood, Staines, England, assignor to W. E. Sykes Limited, Staines, England Application dune 18, 1953, Serial No. 362,451

Claims priority, application Great Britain June 18, 1952 9 Claims. (Cl. 51-45) This invention relates to machines for grinding gear tooth and like profiles of the kind comprising a grinding wheel having a spirally ribbed periphery which has a profile corresponding to the rack form or equivalent profile of the tooth pitch desired, the required profile being generated by rotating the wheel and work in the required relation whilst effecting a relative movement between the grinding wheel and the work in the general direction of the axis of the work. More particularly the invention is concerned with improved means in a machine of this kind for imparting simultaneous and co-ordinated relative motions to the grinding wheel and the work such that in addition to rotation of the grinding wheel and work about their respective axes, and relative movement of the grinding wheel and the work in the direction of the axes of rotation of the work there is also afforded a coordinated relative movement between the axes of rotation of the grindin wheel and work respectively for increasing and/ or decreasing the distance between the said axes.

It is the object of the present invention to provide a simple and effective arrangement of a machine for the above mentioned purpose whereby gear tooth and like profiles, particularly of a barrel or other tapered or curved form, can be ground.

In accordance with the invention therefore there is provided a machine of the kind referred to for grinding gear tooth and like profiles having means for imparting simultaneous and co-ordinated relative motions to the grinding wheel and the work to cause rotation of the grinding wheel and the work about their respective axes and relative movement of the grinding wheel and the work in the direction of the axis of rotation of the work and including a crank or other member which is rotatable to cause reciprocation of a rack meshing with a pinion which is thereby rotatable to afford by means such as a threaded rod and nut a co-ordinated relative movement between the axes of rotation of the grinding wheel and the work respectively for increasing and diminishing the distance between the said axes. In a preferred machine the pinion is arranged to impart the required movement to a slide carrying the grinding wheel, this motion being co-ordinated with the motion of the work-piece.

Figures 1, 2 and 3 are diagrammatic end elevations of three involute gears having the same tooth characteristics but of ditfereut outside diameters;

Figure 4 is a side view, more or less diagrammatic, of a laminated gear of conical form;

Figure 5 is an end view of such a gear;

Figure 6 is a side view of a laminated gear similar to that of Figure 4, in which the laminations are relatively displaced angularly to form a helical gear;

Figure 7 is a sectional elevation of a machine constructed in accordance with the invention for grinding gear tooth and like profiles;

Figure 8 is an elevation of the grinding wheel;

Figure 9 is a part longitudinal section of the wheel;

Figure 10 is an end view of Figure 7.

States Patent ,7 2,836,014 Patented May 27, 1958 It is known that involute gears having the same number of teeth, the same base circle diameter, and having a gear tooth form which can be enclosed in the same rack tooth form, can be generated to have different outside diameters. diagrammatically in Figures 1, 2 and 3. The involute form of each gear is constructed on the same base circle D and in each case the gear tooth is based on the same rack tooth form A. The outside diameter D of the gear shown in Figure 1 is greater than the outside diameter D of the gear shown in Figure 2, and the outside diameter D of the gear shown in Figure 3 is less than D if a number of gears are produced as thin laminae having their outside diameters varying progressively from D to D and these are assembled in their progression of diameters with the axes of symmetry of the gear teeth in line, a gear will be produced as shown diagrammatically in Figures 4 and 5 having an outside diameter of conical form, a constant cylindn'cal base circle diameter, and the same rack tooth form equivalent at any diameter of the conical form. Also, if the axes of symmetry of the gear teeth of successive laminae are given an angular dis placement, a helical gear of conical outside form will be produced as shown in Figure 6. Gears of this form have numerous uses, particularly for use as gear shaper cutter, and this invention is concerned with means for forming such gears or cutters by the generating principle.

The invention will be described as applied by way of example to a gear grinding machine having a grinding wheel of the form shown in Figures 8 and 9. This wheel is of generally cylindrical shape having an axis 1 and having formed on its periphery a helical thread or worm 2, the cross section 3 of which is constant and corresponds to the rack form of the tooth pitch it is desired to generate. The grinding wheel, shown generally at 4 in Figures 7 and 10, is mounted on a shaft 5 carried in bearings 6 secured to a slide 7 which can be displaced in a slideway on guides 8 formed in a table 9 which is supported from a main frame structure 10. A worm wheel 11 secured to the grinding wheel shaft is driven by a worm 12 on a shaft 13 rotatable in a bearing 14 on the slide 7. The shaft 13 is formed with splines 15 and is slidable within and driven by a splined sleeve 16 rotatably mounted in a bearing 17 on the table 9. A bevel gear 13 integral with the sleeve 16 meshes with a bevel gear 19 secured to a vertical shaft 20 which is driven by bevel gears 21 from a horizontal shaft 22 driven by a belt 23 and pulleys from an electric motor 24 or other convenient source of power. The splined shaft 15 slidable in the driving sleeve 16 permits the grinding wheel to be rotated while the slide 7 which carries it can be moved at a slow speed along the slideway 3. For displacing the slide 7, a lug 25 extends downwardly from the slide and has threaded engagement with a threaded shaft or screw 26 mounted inbearings on the table 9. A gear wheel 27 is secured to the shaft 26. l

The work gear 28 is mounted upon a spindle 29 held between centres 39 and 31 mounted in brackets 32 and 33 on a slide 34 movable in slideways 35 which are formed in a head 36 mounted for angular adjustment about a horizontal axis. For this purpose the rear of the head is formed with a spigot portion 37 surrounded by a flange 38 which fits within a socket recess 39 with the flange bearing against a circular slide surface 40. The socket recess is formed in the side of a hollow column '41 which rises from the main frame structure 10. Any

in a bracket 43 on the head 36 and having threaded 'en- Examples of three such gears are shown.

' gagernent with the slide.

meshes with a gear 45 which through a clutch 45a drives a shaft 46 rotatably mounted in the head and driven by a bevel gear 47 meshing with a bevel gear 48 on a sleeve 49 rotatably mounted in the head 36 and aligned with the axis of angular adjustment of the latter. The sleeve 49 is integral'with a second bevel gear 50 meshing with a bevel gear 51 on a vertical shaft 52 carried in bearings 53 secured to the hollow column 41. p

Rotation of the work gear 28 is effected by a carrier 54 secured to the work spindle 29 and engaged by a collar 55 secured to the centre spindle which is driven by meshing gears 56from a shaft 57, all mounted in the slide 34. The shaft 57 has a splin ed portion 58 slidably engaged in asplined sleeve 59 rotatably mounted in the head 36 and formed integral with a bevel gear 60 which meshes with a bevel gear 61 on a horizontal shaft 62. The shaft 62 g is concentric with the aXis'of angular adjustment of the head 36 andextends freely through the previously mentioned sleeve 49.

The shaft 22'driven by the motor 24 has secured to it a gear annulus 63 of a differential gear including a second gear annulus 64 secured to a shaft 65 coaxial with shaft 22 and planet gears 66 on a rotatable carrier 67. The shaft 65 drives through change gears 68 a shaft .69 which is connected by bevel gears 70 to a vertical shaft 71 driving the shaft 62 through bevel gears 72 and thereby rotates the work gear 28 through .the gearing. previously described. The change gears'68 are selected in accordance with the number of teeth required in the work gear and the number of starts of the helical or screw A gear 44 on the shaft 42' crank disc will cause the rack 104 to be reciprocated vertically thereby giving reciprocating angular motion to the pinion 107. The clutch 111 being engaged with pinion 107 reciprocating angular motion will be given to shaft 110 and by the gears 84 .and 2'7 to screw 26.

The amount of barrelling can be chosen by: a (a) The setting for the throw of the crank pin 103; (b) The choice of change gears 101'and 75 thus determining the angular movement of the crank disc 103 for any travel of the slide 34 along the guide ways 35.

F or the production of work with a taper-root diameter clutchlll is' engaged with pinion 109 when the screw 26 is given rotation in one direction only. .1 7

Change gears 101and 75 can be selected to give any number of revolutions of the screw 26 in one direction, either clockwise or anti-clockwise for any movement of the slide 34 along the guide.ways 35.

. The machine may be set by hand in correct cry-relation of movements by turning shaft 76 by the square end 94 provided or by turning thesha ft 110 by its'square end 113 with clutches 93, 45a and 111 engaged or disengaged as required.

The horizontal slow speed shaft 76 is also connected 4 through bevel gears 85 to a shaft 36 and thence through to the carrier 67 of the differential gear. Worm wheel 91.

form of the grinding wheel 4. The vertical shaft 71 also 7 drives a shaft 73 through bevel gears 74 and thence through change gears 75 and the drive is transmitted to a slow speed horizontal shaft 76. Bevel gears 77 connect the horizontal shaft 76 to the vertical shaft 52 which drives the screw 42 controlling the slide 34, as previously described. By this means the slide 34 is slowly traversed in its slideway. The horizontal shaft 76,

is also connected to the gear 100 through change gears 101. The gear 100 is keyed to the shaft 102 as is also the crank disc 103. A rack member 104 is mounted in a slide 105 which slide is fixed to the main structure 10. The rack member is formed with a T head in which is formed a slot 106. The teeth of the rack engage the pinion 107. A crank pin 108 adjustably mounted in a T slot on the face of the crank disc 103 engages the slot 106 so that rotation of the crank disc 103 causes the rack 104 to move vertically in its slide 105 and so imparts a reciprocating angular motion to the 'pinion 107 the.

amount of such reciprocation being dependent on the angular movement of the crank disc 103 and the distance of the crank pin 108 from the centre of the crank disc. Thus, referring to Figure 10, if the crank disc revolves clockwise the rack will rise vertically until the crank pin 108 arrives at the top dead centre of the crank disc 103.

After passing the top dead centre the crank pin will cause the rack to fall vertically. The gear 100 drives the pinion 109. Both the pinion 109 and the pinion 107 can revolve freely on the shaft 110 and both are provided with fine clutch teeth to engage the clutch 111 which is slidably key-mounted on shaft 110.

Appropriate movement of clutch 111 will cause either the pinion 107 or the pinion 109 to be connected to shaft 110. Shaft 110 drives'the screw 26 through gears 84 and '27. By this means the slide 7 carrying the grinding wheel 4 is given motion either towards or away from the work gear 28 dependent on the rotation of the screw 26. v V 7 When shaft 76 revolves, the crank disc 103 revolves,

7 being driven by the appropriate change gears 101 and the gear 100 through the shaft'102 carrying the crank disc 103. As before described, the passage of the crank pinj 9W? fd angawavimm: the. t p. dea ntre. f. he

change gears 87 and bevel gears 88 to a shaft'89 carrying a worm 90 meshing with a worm wheel 91. A worm 91a meshes witha worm Wheel ring 92 formed on or secured and worm 91a are both mounted on and keyed to a shaft 91b. This differential gear and its connection with the horizontal shaft 76 is'only employed when generating helical gear tooth forms. When producing "straight or spur gear forms, the differential gear is disconnected, for. example by removing the change speed gears 87 so that the planet pinion carrier 67 is locked by its engagement with the worm 91'and the two

shafts

22 and 65 revolve at thesame speed,

The drive of the horizontal shaft 76 from'the change.

speed gears 75 can'be controlled by a clutch indicated at 93 on shaft 73. By disengagingthis clutch, the shaft 76 a can be rotated by hand by applying a key to its squared end 94. In a similar manner, by hand rotation of the g ing wheel slide 7 are initially set-so that the slide 34 can be slowly traversed past the wheel for the generating of the required tooth form, the speed of traverse being prede-- terminedby suitable choice of the change speed gears 75. It is necessary that the. rotation of the work gear should M be suitably coordinated with the speed of rotation of the spirally ribbed grinding wheel, and this is predetermined by an appropriate choice of the change speed gears 68. The grinding wheel is also" given a slow movement either towards or away from the work gear according to the direction of naversexof the, slide 34, to give the work the desired conical-or tapered form, the amount of taper being predetermined by a suitable choice of the change speed gears and 101. In Figure 7 the grinding Wheel is shown in a withdrawn position halfway between the end diameters D and D (Figures 4 to 6) of the work gear. It will be clear that if the work is traversed down-. wardly, the grinding wheel slide must be moved inwardly at the same time to produce the desired taper frem D 10D;- 1 7 V V f i I When it is desired to generate helical gear forms, the

' head 36 is adjusted in its spigot mounting to the required inclination with respect to the line of the helix of the grinding wheel and the helix of the work gear. The necessary additional rotation of the work gear is afiorded by the difierential gear which is driven through suitably chosen change speed gears 87. By this means the central planet pinion carrier 67 of the differential gear is revolved at a slow speed and additional motion is thereby imparted to the shaft 65 and thence to the work gear.

It will be understood by those skilled in the art that co-ordinated motions may be obtained by other than change gears, and the scope of the present invention is not restricted thereto. It is also to be understood that relative motion may be obtained between the grinding wheel and gear by other than the specific embodiment illustrated herein and the scope of the present invention is not restricted thereto.

The invention is not restricted to the production of involute tooth forms. It can be applied with particular advantage to the grinding of gear shaper cutters, which may be of involute or other tooth form. For example, cutters for producing sprocket wheels or clutch elements of gear form may be conveniently and economically generated on machines according to the invention.

claim:

1. In a machine of the type described, a helical-profile grinding tool, means for rotatably supporting said grinding tool, means for rotatably supporting a workpiece, means for rotatably driving said grinding tool and Workpiece in timed relation, means for reciprocating said grinding tool in a direction perpendicular to the axis of rotation of the workpiece, and means for moving the workpiece in the direction of its axis of rotation in timed relation to the reciprocation of said grinding tool.

2. In a machine of the type described, a motor, a base, a first slide member mounted on said base, a grinding tool rotatably mounted on said first slide member, a second slide member mounted on said base and movable in a direction out of the plane of movement of said first lane member, an arbor rotatably mounted on said second slide member for holding a workpiece, means operable by said motor to rotate said grinding tool and said arbor in timed relation, means operable by said motor for moving said second slide member in the direction of the axis of the arbor, and means operable by said motor for reciprocating said first slide member in a direction perpendicular to the axis of the arbor in timed relationship with the movement of said second slide member.

3. A machine in accordance with claim 2 wherein the means operable to reciprocate said first slide member includes a rack slidably mounted on said base and engageable by a revolving crank whereby said rack is caused to reciprocate, a pinion intermeshing with said rack, a threaded rod on which said pinion is secured, and means on said first slide member for threadably engaging said threaded rod.

4. In a machine of the type described, a base, a motor, a first slide mounted on said base for rotatably supporting a grinding tool, a head frame having a circular spigot portion at one end thereof adapted to snugly fit in a circular recess provided in said base, a second slide slidably mounted on said head frame for rotatably supporting a workpiece, said second slide being movable in a direction out of the plane of movement of said first slide, means to drive said first and said second slides reciprocably in timed relationship, means operable by said motor to rotatably drive said grinding tool, and means operable by said motor to rotatably drive the workpiece in timed relation to the rotation of said grinding tool, said last-named means including a rotatable shaft extending centrally through the recess of said base and the spigot portion of said head frame, said shaft having a gear at one end thereof drivably connected to the workpiece.

S. in a grinding machine of the type described, means rotatably to support a helical-profile grinding tool, means for rotatably supporting a workpiece with its axis perpendicular to the axis of said tool, means for rotatably driving said grinding tool and the workpiece in timed relation, means to reciprocate said workpiece axially, and means to reciprocate said grinding tool with respect to said workpiece perpendicularly to the axis thereof and in timed relation to the axial travel of said workpiece.

6. The invention according to claim 5 wherein said last-named means includes a rack, means to reciprocate said rack in timed relationship to the axial movement or said workpiece, and a pinion engaging said rack, said pinion being geared to a threaded member that engages one of said supporting means.

7. The invention according to claim 5 wherein the grinding tool supporting means is a slide member reciprocable upon a base member towards and away from the workpiece.

The invention according to claim 6 wherein said rack is provided with a slot at one end thereof extending transversely to the line of the rack and is reciprocated upon rotation of a rotatable member by a crank pin mounted upon said rotatable member and extending into said slot.

9. The invention according to claim 8 in which said crank pin is adjustably mounted on said rotatable memher and is fixable at varying distances from the axis of rotation thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,693,781 Hanson Dec. 4, 1928 2,307,238 Ross Jan. 5, 1943 2,360,235 Jellis Oct. 10, 1944 2,385,650 Rickenmann Sept. 25, 1945 2,424,191 Rickenmann July 15, 1947 2,443,410 Wickman June 15, 1948 2,482,800 Ross Sept. 27, 1949 2,597,648 Lucas May 20, 1952 2,620,599 Riley Dec. 9, 1952 2,642,702 Staples June 23, 1953 FOREIGN PATENTS 664,539 Great Britain Jan. 9, 1952