US3589073A

US3589073A - Grinding device

Info

Publication number: US3589073A
Application number: US794226*A
Authority: US
Inventors: Isamu Okamoto; Mutsuo Hosoi
Original assignee: Okamoto Kohsakukikai Seisakusho KK
Current assignee: Okamoto Kohsakukikai Seisakusho KK
Priority date: 1968-08-17
Filing date: 1969-01-27
Publication date: 1971-06-29
Anticipated expiration: 1988-06-29
Also published as: GB1213431A

Abstract

A gear grinder having a prime mover to drive both a grindstone and a work to be ground in synchronism with each other. The gear grinder has a power transmission means to deliver output from the prime mover to both the work and the grindstone for moving them, which transmission means includes a uniform universal joint having a spur gear slidably engaging a pinion located on power receiving side. The spur gear slides along said pinion as one of the work and the grindstone moves relative to the other.

Description

I United States Patent 1111 3,589,073

[72] Inventors lsamu Okamoto: [56] References Cit d MUISUO "050i, b"! 0f Yokohama, Japan UNITED STATES PATENTS 23 5 2,360,235 10/1944 JCIliS 51/95 3,443,34] 5/l969 Soichiro Honda et ai. 51/105 Pmmed m1 3 487 584 1/1970 Rickenmann 51/95 [73] Assignee Kabushiki Kaisha Okarnoto Kohsakukikai Seisakusho Primary Examiner-Othell M. Simpson Yokohama, Kanflgawa Prefecture, Attorneywaters, Roditi, Schwartz & Nissen Japan [32] Priority Aug. 17, 1968 a [33] Japan 4358638 ABSTRACT: A gear grinder having a prime mover to drive both a grindstone and a work to be ground in synchronism with each other. The gear grinder has a power transmission [54] F means to deliver output from the prime mover to both the a m mg work and the grindstone for moving them, which transmission [52] U.S.Cl 51/95 means includes a uniform universal joint having a spur gear [51] lnt.Cl B24h 3/34 slidably engaging a pinion located on power receiving side. Field of Search 5l/94, 95, The spur gear slides along said pinion as one of the work and OH, the grindstone moves relative to the other.

PMENYEU JUNZQ 97! SHEET 01 OF PMENTEO M29 Ian SHEET 02 0F 12 FiG.4

PATENTEU JUHZS m SHEET [15 HF FIG.

PATENTED JUN29 1911 SHEET 0 9 [JF FIG.9

PATENTED JUHZS m SHEET 10 [1F FIG. BO

PATENTEDJUNNIBTI 3589073 SHEET 11m 12 GRINDING DEVICE This invention relates to a grinding device, and more particularly to a gear grinder of simple construction in which a work and a grinding wheel are driven by a single driving prime mover with high accuracy by using rigid driving mechanism without using any spline shafts and worm gears.

Generally speaking, high accuracy and high efficiency are required as essential features in grinding devices, especially in gear grinders. From the viewpoint of achieving high accuracy, it is preferable to make driving mechanism, as simple as possi ble, which mechanism drives a grinding wheel and a work, because the more complicated the driving mechanism is, the lower the rigidity of the driving mechanism will be, and the low rigidity results in a reduced accuracy. From the viewpoint of achieving high efficiency, the grinding means should be adjustable for different conditions of the grinding wheel and the work, ie it should be easily adjustable.

In a known gear grinder, an electric motor drives both a work and a grinding wheel in synchronism with each other by using a driving mechanism. For instance, continuous gear generation is carried out by using a hob-shape grinding wheel formed in a rack-type thread, while producing generating movement on both the grinding wheel and the work. However, such known gear grinder has disadvantages in that a number of slidable spline shafts are used in its driving mechanism together with worm gears in its final speed reduction means, for the purpose of providing controllability for various operative conditions, which spline shafts and worms result in a comparatively low rigidity of the driving mechanism and a reduced overall accuracy.

In another known gear grinder, two synchronous motors are used for driving a grinding wheel and a work separately yet in synchronism with each other so as to carry out continuous gear generation. This type of gear grinder can prevent the reduction in the rigidity of the driving mechanism by driving the grinding wheel and the work separately with separate synchronous motors, respectively. However, with the two synchronous motors, the control mechanism for driving them in synchronism becomes complicated, and its starting operation becomes complicated. In addition, the gear grinder has disadvantage in that its accuracy is reduced as the grinding resistance of the work varies during grinding operation, and that it is not suitable for generating accurate gear teeth on segment-shaped gear wheels.

Therefore, an object of the present invention is to provide a new gear grinder which obviates the aforesaid difiiculties of known gear grinders.

Another object of the present invention is to provide a gear grinder easily adjustable for different conditions of grinding wheels and works, so as to provide a high production efficiency.

It is another object of the invention to provide a gear grinder in which a highly stable accuracy can be ensured during fine adjustment to meet different conditions of the grinding wheel and the work.

A further object of the present invention is to provide a gear grinder capable of efficiently producing various spur gears, helical gears, and the like, and also capable of heavy grinding operation.

According to the present invention, there is provided a gear grinder comprising a base, a grinding wheel head holding a grinding wheel and movably mounted on said base, a worktable holding a work and movably mounted on said base, a driving prime mover, an operating mechanism to operate both said grinding wheel and said work, a power transmission means including at least one constant velocity universal joint to deliver output from said prime mover to said operating mechanism, and a crowning mechanism to be actuated in response to vertical movement of said work, said constant velocity universal joint transmitting power between said grinding wheel and said work and consisting of a spur gear slidably engaging a pinion located on power receiving side, said spur gear sliding along said pinion as one of worktable and said grinding wheel head moves relative to the other.

Other objects and a fuller understanding of the present invention may be had referring to the following description and claims, taken in conjunction with the accompanying drawings, in which;

FIG. I is a side view of a gear grinder according to the present invention;

FIG. 2 is a schematic perspective view of a driving mechanism to drive a grinding wheel and a work in the gear grinder of FIG. 1;

FIG. 3 is a schematic perspective view of a shifting mechanism of the grinding wheel, a grinding wheel in feed mechanism, and a crowning mechanism;

FIG. 4 is a vertical sectional view of a constant velocity universal joint usable in a driving mechanism of the grinding wheel and the work;

FIG. 5 is a horizontal sectional view of a slidable spur gear means in the driving mechanism of the grinding wheel and the work;

FIG. 6 is a vertical sectional view of a grinding wheel head driving mechanism in the grinding wheel in feed mechanism;

FIG. 7 is a horizontal sectional view of the mechanism of FIG. 6;

FIG. 8 is a vertical sectional view of a means for regulating for lead angle of the grinding wheel;

FIG. 9 is an elevation of a means for regulating for helix angle of the work;

FIG. 10 is a vertical sectional view ofthe means of FIG. 9;

FIG. 11 is a plan view of the crowning mechanism; and

FIG. 12 is an elevation of the crowning mechanism of FIG. 11, with a part cut away.

Like parts and members are designated by like numerals and symbols throughout the drawings.

Referring to FIGS. 1 to 3, illustrating the overall construction of a gear grinder according to the present invention, a base 1 supports a grinding wheel actuating mechanism 2 mounted on its one end, and a work actuating mechanism 3 is disposed at its opposite end.

The grinding wheel actuating mechanism 2 consists of a grinding wheel head base 11 reciprocative in the longitudinal direction of the base 1, a grinding wheel head lower board 12 mounted on the grinding wheel head base I1 so as to be reciprocative at a right angle to the longitudinal direction of the base I, a grinding wheel head upper board 13 mounted on the grinding wheel head lower board 12 so as to be laterally swingable, and a grinding wheel head 14 secured to the grinding wheel head upper board 13. A hob-shape grinding wheel G, which is formed like a rack-type screw, is replaceably attached to the grinding wheel head 14.

The work actuating mechanism 3 consists of a column 21 mounted on the base 1, a hydraulic cylinder means 22 mounted within the column 21, a vertically reciprocating plate 23 connected to the hydraulic cylinder means 22 and disposed on that side of the column 21 which faces the grinding wheel G, and a worktable 24 pivotally secured to one side of the vertically reciprocating plate 23. The worktable 24 has a pair of

arbor holders

25 and 26 secured to the upper end and the lower end thereof, respectively, so as to replaceably hold the upper end and the lower end of an arbor 27 carrying work W, or a gear to be ground. The work W is secured to the middle point of the arbor 27 or to the proximity thereof. For simplicity, the details of the

arbor holders

25 and 26 are not shown, but it is well-known in the art toconstruct them so that the lower arbor holder 26 opens and closes as the upper arbor holder 25 moves upwards and downwards, respectively. The arbor 27 can be secured to the arbor holders by hydraulic chucks at any position so as to keep the work W engageable with the grinding wheel G.

The grinding wheel actuating mechanism 2 further includes a shifting means to feed the grinding; wheel G in its axial direction, a grinding wheel in feed means to feed the grinding wheel G in the radial direction of the work W, and a lead angle regulating mechanism to incline the grinding wheel G. The work actuating mechanism 3 includes a feeding means to vertically reciprocate the work W along its tooth trace, and a helix angle regulating means for inclining the work W along the helix angle thereof.

The grinding wheel actuating mechanism 2 and the work actuating mechanism 3 are connected to a driving mechanism 4 for driving the grinding wheel G and the work W. A grinding wheel truing mechanism 5 is attached to the grinding wheel actuating mechanism 2. An operating panel 6 is mounted on one sidewall of the base 1, while a crowning mechanism 7 is mounted on another side of the base 1.

The driving mechanism 4 for driving the grinding wheel G and the work W will now be described in detail referring to FIG. 2. A motor 31 is mounted in the grinding wheel head 14, and one end of a grinding wheel spindle 33 is connected to the motor 31 with a coupling 32. The grinding wheel G is of screwlike hob shape and coaxially secured to the opposite end of the grinding wheel spindle 33. The grinding wheel G is directly driven by the motor 31 through the coupling 32 and the grinding wheel spindle 33.

A gear 34 is secured to the grinding wheel spindle 33 at an intermediate portion thereof, and the gear 34 meshes with another gear 35 at a right angle thereto. The gear 35 is connected to a constant velocity universal joint 37 through a shaft 36, so as to deliver the motor output power toward the Work W. A connecting rod 38, which is preferably hollow, is secured to the constant velocity universal joint 37 at one end thereof, while the opposite end of the rod 38 is connected to another constant velocity universal joint 39 located in the proximity of the work G. Rod 38 has been shown with a threaded connection, at its ends, with

universal joints

37 and 39. However, the connection may also be formed with splines to enable rotation in opposite directions while preserving the connection.

A shaft 40 is connected to the constant velocity universal joint 39 at one end thereof, and a spur gear 41 having comparatively wide tooth is coaxially secured to the shaft 40. THc spur gear 41 meshes with a pinion 43 pivotally secured to a stud 42 mounted on the reciprocating plate 23. The pinion 43 has teeth wider than those of the spur gear 41. The spur gear 41 is axially slidablc while meshing with the pinion 43. The pinion 43 meshes with another spur gear 44 coaxially secured to a shaft 45, which is operatively connected to another shaft 51 through an index gear train. The index gear train includes gears 46, 47 a shaft 48, and gears 49, 50. The shaft 51 extends from the vertically reciprocating plate 23 to the worktable 24, and a gear 52 coaxially secured to the extended end of the shaft 51 meshes another gear 53 at a right angle thereto. A shaft 54 carrying the gear 53 is operatively connected to a chuck shaft 60 at the lower arbor holder 26 through a reduc ing gear train. The reducing gear train includes

gears

55, 56, a shaft 57, and gears 58, 59. The chuck shaft 60 is operatively connected to the spindle 27 of the work W in alignment therewith.

As the motor 31 rotates, its output power acts to rotate the constant velocity universal joint 37 in the proximity of the grinding wheel G through the gears 34, 35, and the shaft 36. Accordingly, the other constant velocity universal joint 39 rotates at the same speed with the universal joint 37 through the connecting rod 38, so that the spur gears 41 and 44 can be rotated through the shaft 40 and the pinion 43. Then, the chuck shaft 60 is rotated through the shaft 45, the index gear train, a direction changing gear trains including the

shafts

51, 54, and gears 52,53, and the reducing gear train. As a result of it, the work W rotates in synchronism with the grinding wheel G, while facing with each other.

In grinding the work, the grinding wheel G and the work W are mounted on the gear grinder, and the grinding wheel side constant velocity universal joint 37 moves together with the grinding wheel head 14 in the following cases; namely, in the case that the grinding wheel head 14 moves in the axial direction of the grinding wheel G in order to shift a particular lead of the grinding wheel G to a position corresponding to a lead of the work W to be ground; in the case that the grinding wheel head 14 is inclined relative to the axis of the grinding wheel G for the sake of inclining the tooth trace of the grinding wheel G by an angle corresponding to the angle of the tooth trace of itself i.e. an lead angle thereof; and in the case that the grinding wheel head 14 moves perpendicular to the axis of the grinding wheel G, so as to grind the work W by bringing the tooth trace of the grinding wheel G to the corresponding tooth trace of the work W. When the position of the other constant velocity universal joint 39 is shifted in response to the shift of the grinding wheel G, the spur gear 41 slides along the pinion 43 while being meshed with it by a distance corresponding to the displacement of the universal joint 39, and the spur gear 41 is indexed there.

Similarly, in grinding helical gears, when the worktable 24 is inclined about the axis perpendicular to that of the work W by an angle in accordance with the helical angle of the work W, and further in the course of grinding the work W, when the worktable 24 moves along the direction of the tooth trace of the work W for vertically moving the work W in the axial direction of the work W while keeping it in contact with the grinding wheel G, the constant velocity universal joint 39 in the proximity of the work W also moves together with the worktable 24. At the same time, the spur gear 41 slides along the pinion 43 while keeping meshed therewith by a distance corresponding to the displacement of the universal joint 39, and the spur gear 41 is indexed there.

When the grinding wheel G or the work W is replaced with one having a different diameter, the grinding wheel head 14 moves, and the constant velocity

universal joints

37 and 39 cause the spur gear 41 to slide along the pinion 43 to index it properly.

When the pitch (or module) of the work W is changed, the index gear

train including gears

46, 47, 49, and 50 should be changed.

in grinding a helical gear W, when the worktable 24 is turned about the axis perpendicular to that of the work -W and inclined so as to bring the tooth trace of the work W to an angular position corresponding to the tooth trace of the grinding wheel G or to its helical angle, the gear 53 rotates about the axis 51 of the gear 52 while keeping meshed with the gear 52 at a right angle.

FIG. 4 shows details of the constant velocity

universal joints

37 and 39, and FIG. 5 shows the construction of the slidable portion between the spur gear 41 and the pinion 43. As shown in the figures, a bearing case 61 is mounted above the grinding wheel head 14, and

ball bearings

62 and 63 are secured to either end of the bearing case 61, respectively, so as to bit the shaft 36 at both ends thereof. The gear 35 is secured to the shaft 36 at about the center thereof, and the gear 35 meshes the gear 34 secured to the grinding wheel spindle 33. The

right-hand end of the shaft 36,.as seen in FIG. 4, extends out of the bearing 63, and a coupling 64 of the constant velocity universal joint 37 is coaxially connected to the end of the thus extended portion of the shaft 36. One end of the connecting rod 38 is fitted in a movable member 37a of the constant velocity universal joint 37 and secured thereto.

A slide block 65 is secured to the back surface of the vertically reciprocating plate 23 in the column 21, and

ball bearings

66 and 67 are mounted in either end of the slide block 65, respectively, for fitting the shaft 40. The spur gear 41 is secured to the shaft 41 and meshed with the pinion 43 pivotally supported by the stud 42 through

ball bearings

68 and 69, which stud is secured to the reciprocating plate 23. The left-hand end of the shaft 40, as seen in FIG. 5, extends out of the ball bearing 66, and another coupling 70 is coaxially secured to the end of the thus extended portion of the shaft 40. The constant velocity universal joint 39 is connected to the coupling 70, and the opposite end of the connecting rod 38 is fitted in a movable member 39a of the constant velocity universaljoint 39 and secured thereto.

Cylindrical covers 71 and 72 are secured to the bearing case 61 and the slide block 65, so as to surround the constant velocity joints 37 and 39, respectively. A cover bellows 73 for the connecting rod 38 is secured to the

covers

71 and 72 at either end thereof by

wire bands

74 and 75, respectively.

The grinding wheel head upper board 13 supports the grinding wheel head 14 at one side thereof and the grinding wheel truing mechanism 5 on the opposite sides thereof, as depicted in FIG. 2. The grinding wheel truing mechanism 5 comprises a base board 81 mounted on the grinding wheel head upper board 13 so as to be slidable thereon in parallel with the grind ing wheel spindle 33, a holder 82 mounted on the baseboard 81 so as to be movable cross to the grinding wheel spindle 33, and a handwheel 83 to actuate the cross movement of the holder 82. A motor 84 (for truing the grinding wheel) is mounted on the grinding wheel head 14, and the motor 84 has a joint 85 connected to a shaft 86 having a worm 87 secured thereto. The worm 87 is operatively connected with a screw shaft 96 through a worm gear 88, a shaft 89 of the worm gear 88, and another indexing gear train, which includes gears 90, 91, 92, a shaft 93, and gears 94, 95. The screw portion of the screw shaft 96 operatively engages a nut 97 secured to the baseboard 81.

A gear 98 is coaxially secured to the shaft 89 having the worm gear 88, and the gear 98 is operatively connected to the grinding wheel spindle 33 through an intermediate slidable pinion 99 and a gear 100 secured to the spindle 33. For truing the grinding wheel G, a suitable dresser (not shown) is mounted on the holder 82, and the intermediate slidable pinion 99 is shifted between the

gears

98 and 100 so as to mesh with each other. Then, the motor 84 is started to drive the grinding wheel G, and at the same time, the base board 82 is reciprocated through the screw shaft 96. The truing of the grinding wheel G is carried out by feeding the holder 82 toward the grinding wheel G by turning the handwheel 83.

For different grinding wheel G having different pitches (modules), the

gears

90 and 92 of the indexing gear train are changed.

The details of the grinding wheel shifting mechanism, which axially shifts the grinding wheel G so as to bring its tooth trace to the corresponding tooth trace of the work to be ground, will now be described, referring to FIG. 3. A handwheel shaft 101 is pivotally supported inside the operating panel 6, and a handwheel 102 is secured to the outer end of the handwheel shaft 101. A bevel gear 103 is secured to the inner end of the hand wheel shaft 101, which is operatively connected to another screw shaft 108 through a bevel gear 104 meshing with the bevel gear 103 at a right angle on the same horizontal level, a gear 106 secured to the shaft 105 of the bevel gear 104, and a gear 107 secured to the outer end of the screw shaft 108 and meshing with the gear 106 at a right angle thereto. The screw portion of the screw shaft 108 is operatively fitted in a nut member 109 secured to the grinding wheel head lower board 12 supporting the grinding wheel head 14. When the handwheel 102 is turned so as to rotate the handwheel shaft 101 either clockwise or counterclockwise, the screw shaft 108 is actuated through the bevel gears 103, 104, the shaft 105, and gears 106, 107, and as a result of it, the grinding wheel head 14 axially moves together with the grinding wheel head lower board 12 by the engagement of the screw shaft 108 with the nut member 109.

The handwheel shaft 101 has a worm gear 110 secured to the intermediate portion thereof, which meshes with a worm 112 directly connected to a motor 111 mounted inside the operating panel 6. For automatic operation of the grinding wheel head 14, the motor 111 is actuated, and the grinding wheel head 14 can be reciprocated through the worm 112, the worm gear 110, and the handwheel shaft 101.

The grinding wheel in feed mechanism for moving the grinding wheel G perpendicular to the grinding wheel spindle 33 for bringing the tooth trace of the grinding wheel G in contact with the corresponding tooth trace of the work W will now be described. Such mechanism is shown in FIG. 3, and its details are partially depicted in FIGS. 6 and 7.

Referring to FIG. 3, another handwheel shaft 121 is pivotally supported inside the operating panel 6 of the base 1, and a handwheel 122 is secured to the outer end of the handwheel shaft 121. A gear 123 is secured to the inner end of the handwheel shaft 121, which is operatively connected to a screw shaft 134 through a gear 124 meshing with the gear 123, a gear 127 meshing with a gear 126 secured to a shaft of the gear 124, a gear 129 secured to the shaft 128 of the gear 127, a gear 130 meshing with the gear 129 at a right angle thereto horizontally, a gear 132 secured to the shaft 131 of the gear 130, and a gear 133 meshing with the gear 132. The screw shaft 134 has the gear 133 secured to its outer end, and its inner end is fitted in a nut member 135 secured to the grinding wheel head base 11 supporting the grinding wheel head 14. When the handwheel shaft 121 is rotated clockwise or counterclockwise by the handwheel 122, the screw shaft 134 is actuated through the

gears

123, 124, the shaft 125, the

gears

126, 127, the shaft 128, the

gears

129, 130, the shaft 131, and the

gears

132 and 133. As a result of it, the grinding wheel head 14 reciprocates together with the grinding wheel head base 11 by the engagement of the screw shaft 134 and the nut member 135.

The gear 127 is also operatively connected to a motor 136 mounted inside the operating panel 6 through

gears

137, 138, a shaft 139, and gears 140, 141. During operation for grinding the work W, the motor 136 is actuated to rotate the screw shaft 134, so as to automatically feed the grinding wheel head 14 at a low speed for carrying out the grinding operation.

FIGS. 6 and 7 illustrate the details ofthe construction of the screw shaft 134. Referring to the figures, a guide base 151 is mounted on the upper surface of the base 1, and a pair of roller guides 152 and 153 are mounted on either side thereof, respectively. A bracket 154 is disposed between the roller guides 152 and 153. Another pair of roller guides 155 and 156 are mounted on the lower end of the bracket 154 at either side thereof so as to correspond with the aforesaid roller guides I52 and 153. A pair of

closed roller chains

157 and 158 are inserted between the roller guides 155, I56 and the roller guides 152, 153, respectively, so that the bracket 154 can be freely slided. A shaft hole 159 is bored at the center of the bracket 154, and a needle bearing 160 is fitted in the shaft hole 159. At the same time, a pair of

thrust ball bearings

161 and 162 are disposed at the opposing ends of the shaft hole 159. The screw shaft 134 is pivotally supported by the needle bearing I60 and the

thrust ball bearings

161 and 162.

The screw shaft 134 has a shoulder 163 in the proximity of its left-hand end, as seen in FIG. 7, and the gear 133 is secured between the shoulder 163 and the thrust ball bearing 162. Two nuts 164 are screwed to the extreme left-hand end of the screw shaft 134, so as to hold the other thrust ball bearing 161. The front end of a shaft 165 of the crowning mechanism, to be described hereinafter, is secured to the end surface of the bracket 154 so as to surround the nuts 164. A screw portion 134:: is integrally fonned with the screw shaft 134 at the front part thereof and screwed in the nut member 135 secured to the front portion of the grinding wheel head base 11.

When the gear 132 is rotated either by turning the handwheel 122 or by actuating the motor 136, the screw shaft 134 is rotated through the gear 133 meshing with the gear 132 while being supported by the bracket 154 at a certain position, so that grinding wheel head 14 is reciprocated through the threaded engagement between the screw portion 134a and the nut member 135.

When the crowning shaft 165 reciprocates in response to the operation of the crowning mechanism, the screw shaft 134 moves together with the bracket 154, so as to reciprocate the grinding wheel head 14. In this case, the gear 133 slides along the gear 132 while meshing with it so as to transmit the power through the rotating engagement.

The lead regulative mechanism of the grinding wheel for inclining the tooth trace of the grinding wheel G to an angular position corresponding to the tooth trace of the work W, in response to the lead angle of the grinding wheel G, will now be described, referring to FIG. 8. As depicted in the figure, the

grinding wheel head 14 is supported on the grinding wheel head upper board 13, and a roller 171 is inserted between the grinding wheel head upper board 13 and the grinding wheel head lower board 12 through

holders

172 and 173 at one end thereof, so that the grinding wheel head upper board 13 can swing about the roller 171 relative to the grinding wheel head lower board 12. A recess 174 is provided on the grinding wheel head lower board 12 at an end opposing the roller 17], and a bracket 175 is secured to the recess 174 along the outer edge thereof. A tapped cylinder 176 is rotatably supported in the bracket 175. The tapped cylinder 176 is held in the bracket by applying a stopper 177 to the outer end thereof, and by engaging a nut 187 to the inner end of the tapped cylinder 176. A dial 179 is secured to the outer end of the tapped cylinder 176. A screw 180 is screwed in the tapped cylinder 176, which screw 180 has graduation 181 inscribed at the outer end thereof. Mounted to the inner end of the screw 180 is a slider 183 having its upper surface tapered downwards as it extends toward the roller 1717 A roller holder 184 is provided so as to face the recess 174 of the grinding wheel head lower board 12, and a roller 185 is held by the roller holder 184. The roller 185 is supported by a pair of supporting

means

186 and 187 secured to the roller holder 184 in such manner that the lower surface of the roller 185 comes in contact with the upper surface 182 of the slider 183.

When the tapped cylinder 176 is turned by rotating the dial 179, the screw 180 fitted in the tapped cylinder 176 reciprocates, so as to reciprocate the slider 183 together with the screw 180. Thereby, the grinding wheel head 14 swings about the roller 171 through the grinding wheel head upper board 13.

A feeding mechanism to feed the work W along the tooth trace direction for vertically reciprocating the work W during grinding thereof will now be described, referring to FIGS. 2 and 3. As described in the foregoing, a column 21 is provided on the base 1 along the side opposite to the grinding wheel head 14, and a hydraulic cylinder means 22 extends vertically in the column 21, and a piston means (not shown) vertically reciprocates therein. On that surface of the column 21 which faces the grinding wheel head 14, a pair of guide frames 191 and 192 are secured to the opposing vertical sides thereof, and the vertically reciprocating plate 23 moves between the guide frames 191 and 192. The reciprocating plate 23 carries the worktable 24 mounted at the center thereof, and the reciprocating plate 23 is connected to a movable portion (not shown) of the hydraulic cylinder means 22. By actuating the hydraulic cylinder means 22, the reciprocating plate 23 moves vertically along the guide frames 191 and 192, so as to move the work W together with the worktable 24. The velocity of such vertical reciprocation can be steplessly changed.

A tooth trace adjusting mechanism for adjusting the tooth trace of a helical gear to be ground so as to bring the tooth trace of the work W in proper contact with the corresponding tooth trace of the grinding wheel G will now be described, referring to FIGS. 9 and 10. The vertically reciprocating plate 23 holds the worktable 24 in such manner that the worktable 24 is held by a flange 201 formed on the front wall of the reciprocating plate 23 in a manner rotatable about a shaft 202. The ring-shaped flange 201 formed on the front wall of the reciprocating plate 23 comes in tight contact with another ring-shaped flange 203 formed on the rear surface of the worktable 24. A scale 204 indicating the degree of rotation is mounted on one side of the flange 201 of the reciprocating plate 23, and another scale indicating the angular position is mounted on the corresponding sidewall of the flange 203 of the worktable 24.

A pair of bearing

portions

206 and 207 are formed on the front portion of the reciprocating plate 23 above the aforesaid shaft 202, and a shaft 208 is fitted to the bearing

portions

206 and 207. An operating portion 209 is formed at the right-hand end, as seen in FIG. 10, of the shaft 208 projecting out of one side of the reciprocating plate 23. A worm 212 is secured to an intermediate portion of the shaft 208 between the bearing

portions

206 and 207, with

ball bearings

210 and 211 fitted to either end thereof. The worm 212 meshes with a worm gear 213 pivotally secured to the rear wall of the work table 24 with its axis in alignment with the shaft 202.

When the shaft 208 is turned clockwise or counterclockwise by the operating portion 209, the worm gear 213 is turned through the worm 212, so that the worktable 24 rotates in either direction about the shaft 202 together with the work W. The desired angle can be set by using the graduations of the scale 204 on the flange 201 of the reciprocating plate 23 and those of the scale 205 of the worktable 24.

In manual grinding cycle of the gear grinder, both the grinding wheel G and the work W are rotated, and the worktable 24 is vertically reciprocated at a certain velocity, and the grinding is effected by advancing the grinding wheel G by turning the handwheel 122. Such manual grinding cycle is suitable for test grinding and for refinishing.

In semiautomatic grinding cycle of the gear grinder, both the grinding wheel G and the work W are rotated, and the worktable 24 is vertically reciprocated at a certain velocity, and the grinding wheel G is fed in by a predetermined amount when the moving direction of the worktable 24 is changed. After a given grinding operation is completed, finish grinding is effected at the position where the present infeed is completed, and then the vertical reciprocation of the worktable 24 ceases. Such semiautomatic grinding cycle is suitable for test grinding, and for gear production in small quantities.

In full automatic grinding cycle, the same procedure as the semiautomatic grinding cycle is followed until the finish grinding is completed, and then the grinding wheel G automatically is returned to the position ready for starting the next cycle.

A crowning mechanism for effecting the crowning operation on the work will now be described, referring to FIG. 3 illustrating its overall construction as well as to FIGS. 11 and 12 showing its detailed construction. Referring to FIG. 3, a single-groove roller 221 is pivotally supported by a shaft 222 secured to the column 21 above the worktable 24, and a turn roller assembly 223 having a pair of single-groove rollers is pivotally supported by a shaft 224 secured to the lower portion of the column 21. Another turn roller assembly 225 having a pair of single-groove rollers is horizontally supported by a shaft 226 in a rotatable manner on one side of the base 1. A single-groove roller 228 is vertically supported by a shaft 229 secured at one end of a crowning frame 227 mounted on the sidewall of the base 1. An endless rope 230 is spanned over the

rollers

221, 223, 225, and 228, and a portion of the rope 230 is fastened to the reciprocating plate 23 by a fastening means 231 at a position between the

rollers

221 and 223.

Referring to FIGS. 11 and 12, a block 232 is provided by the roller 228 to support a template base 233 thereon. A shoulder 234 is formed on the upper surface of the template base 233 at the front side thereof. A template 236 having an convex-shape contact surface 235 is fitted in the shoulder portion 234, and the template 236 is pressed by a pair of

clamp pieces

237 and 238, and connected thereto by

bolts

239 and 240.

A guide groove 241 is provided on the upper surface of the template base 233 along the longitudinal direction thereof and a clamp plate 243 engages the guide groove 241, which clamp plate 243 is secured by bolts 242 on the upper surface of a receiver 232a engaging the rope 230 at an intermediate portion thereof. The outer surface of the template base 233 at the front side thereof engages the peripheral surface of a guide roller 24S horizontally supported on the block 232 by a shaft 244, so that the template base 233 can be reciprocated on a horizontal plane.

In grinding the work W, when the vertically reciprocating plate 23 is actuated by a hydraulic cylinder means 22, the rope 230 fastened to the reciprocating plate 23 reciprocates along the

rollers

221, 223, 225, and 228, so that the template base 233 having the template 236 secured thereto moves back and forth on the block 232.

A sliding guide base 246 is mounted on the upper portion of the crowning frame 227 secured to the base 1. A slider 249 is slidable supported by a pair of projecting

guide walls

247 and 248 formed on the opposing sides of the sliding guide base 246. A hydraulic servomechanism 250 is mounted at one end of the slider 249 for receiving a force from the template 236.

The hydraulic servomechanism 250 has a rod 251 secured to one end thereof in a reciprocative manner relative to the means 250, and the rod 251 is urged toward the contact surface 235 of the template 236 by an internal spring (not shown). A substantially conical cap 252 is mounted on the ex tending tip of the rod 251, and the tip of the cap 252 is urged against the contact surface 235 of the template 236.

. The hydraulic servomechanism 250 is of known type, and hence, its details are not shown here. in short, it has a hydraulic differential means mounted therein, and when the tip of the rod 251 is depressed by an urging force, the urging force is intensified to a force of predetermined magnitude, so as to produce a moving force. Upon removal of the urging force, it resumes its original position in proportion to the degree of intensification. The degree of intensification can be freely adjusted and can be set at any desired value. Accordingly, when the template 236 moves to urge the rod 251 through the cap 252 in accordance with the configuration of the contact surface 235, the means 250 moves by a certain distance proportional to the displacement of the depressed rod 251, so that the slider 249 advances. if the template 236 further moves to gradually release the rod 251 from the depression by the cap 252 in accordance with the configuration of the contact surface 235, the rod 251 gradually projects and the means 250 also moves in the direction opposite to its previous position by a certain distance proportionate to the projecting displace' ment of the rod 251, and accordingly, the slider 249 recedes.

An adjusting base 253 is supported on the slider 249 at the opposite end thereof in such manner that it is rotatable about a pin 254 disposed at the center thereof. A pair of

slots

255 and 256 are formed on the opposing ends of the adjusting base 253, and the adjusting base 253 is secured to the slider 249 by

stud bolts

257, 258 and

nuts

259, 260 through the

slots

255, 256, respectively. A pair of projecting

guide walls

261 and 262 are formed on the opposing sides of the adjusting base 253, and a slidable plate 263 is slidably held between the projecting

guide walls

261 and 262. The outer end of the crowning shaft 165 is pivotally connected to the slidable plate 263 by a pin 264. The crowning shaft 165 is supported by a plurality of bearing members 265 at its intermediate portion, and its inner end is connected to the grinding wheel head base 11, as described in the foregoing. When the template 236 reciprocates, the slider 249 moves through the driven intensifying means 250, and accordingly, the adjusting base 253 also moves. Thereby, the slidable plate 263 slides between the pair of projecting

guide walls

261 and 262 of the adjusting base 253, and the slidable plate 263 moves at a right angle to the slider 249 in accordance with the inclination of the adjusting base 253, so that the grinding wheel head 14 can be reciprocated through the crowning shaft 165.

With the crowning mechanism of the aforesaid construction, by adjusting the inclination of the adjusting base 253, the extend of the crowning amount can easily be adjusted, including its fine adjustment, and accordingly, various degrees of crowning required and various configurations of the work W can be easily achieved.

The template 236 can be easily replaced with other ones to meet the need of different gear shape and different tooth shape. There is substantially no mechanical load applied to the template, and there is no high accuracy required in the template dimension. The template can be made of iron sheet or the like.

With the gear grinder according to the present invention, various adjustments to meet different conditions of the grinding wheel and the work can be effected very easily, and hence, a high production efficiency is ensured.

Furthermore, when any adjustment is made in response to the change in the conditions of the grinding wheel and the work, the driving mechanism responds to it immediately and accurately, so that highly stable accuracy can be ensured even for fine adjustment.

Therefore, with the gear grinder according to the present invention, various spur gears, helical gears, and the like can be accurately manufactured at a high efficiency, and in addition, heavy grinding can be conducted.

Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that various changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

We claim:

1. A gear grinder comprising a base; a grinding wheel; a head supporting the grinding wheel, :said head being mounted on said base so as to be movable in longitudinal and transverse direction of said base and pivotable with respect thereto; a worktable for supporting a workpiece to be ground into a gear, said table being mounted on said base so as to be movable in a vertical direction and rotatable within the required helix angle of the workpiece gear; a driving prime mover; a power transmission means for transmitting power from said prime mover to both the grinding wheel and the workpiece gear; and a crowning mechanism for effecting a crowning operation on the workpiece gear, said power transmission means including a first constant velocity universal joint associated with the grinding wheel head and a second constant velocity universal joint associated with said worktable, at least one of said universal joints being connected to a spur gear, said spur gear slidably engaging a pinion, whereby said spur gear slides along said pinion in response to either the vertical movement of the worktable or the movement of the grinding wheel head in the longitudinal and transverse directions of the base.

2. A gear grinder as claimed in claim 1, wherein said prime mover comprises an electric motor; and a spindle having one end adapted to carry said grinding wheel being directly connected to said motor, said spindle further being connected in driving relation to said first constant velocity universal joint; and a gear train being associated with said grinding wheel head.

3. A gear grinder as claimed in claim 2, comprising a grinding wheel inclining mechanism adapted to effect inclination of the grinding wheel so that the lead angle of said wheel in the vertical plane includes the axis of said grinding wheel spindle, said grinding wheel inclining mechanism including a grinding wheel head lower board and a grinding wheel head upper board pivotable relative to said lower board; and a tapered slide for controlling the inclination between said lower board and said upper board.

4. A gear grinder as claimed in claim 1, comprising a vertically reciprocatable plate adapted to pivotally support said worktable; a worm gear secured to said worktable; and worm engaging means on said reciprocatable plate for engaging said worm gear whereby the worktable may be rotated in the plane of the required helix angle of the workpiece gear.

5. A gear grinder as claimed in claim 1, comprising means for determining the degree of crowning to be effected to said workpiece gear, said means including a first roller pivotally fastened to a stationary portion of said grinder in proximity to said worktable, a second roller fastened to said base, an endless rope encompassing and tensioned between said rollers, guide means adapted to guide said rope between said rollers, said endless rope being fastened to said worktable so as to rotate about said rollers in response to vertical movement of said workpiece gear, a template being operatively attached to said endless rope so as to correspondingly move in response to rotation of said endless rope, and an actuator being operatively connected to said template so as to actuate said grinding wheel in response to movement of said template.

6. A gear grinder as claimed in claim 5, comprising a crowning adjusting mechanism including a slider positioned on said base so as to be slidable thereon in response to movement of said actuator, an adjusting base rotatably secured to said slider, and including a crowning shaft adapted to control the degree of crowning of said workpiece gear in response to the angular position of said adjusting base, whereby the crowning operation on the workpiece gear is effected through suitable magnification in conformance with the shape of the template.

7. A gear grinder as claimed in claim 1, comprising a grinding wheel head base mounted on said gear grinder base so as to be slidable in one direction relative thereto, and a grinding wheel head lower board being mounted on said grinding wheel head base so as to be manually or automatically movable perpendicular to said direction, said grinding wheel head being mounted on said grinding wheel head lower board.

8. A gear grinder as claimed in claim 7, wherein said grinding wheel head base is adapted to be moved whereby said grinding wheel may come into contact with said workpiece gear.

9. A gear grinder as claimed in claim 1, comprising a hydraulic cylinder means including a vertically reciprocatable member, said worktable being secured to said hydraulic cylinder so as to reciprocate in unison with said reciprocatable member.

10. A gear grinder as claimed in claim 5, wherein said actuator comprises a hydraulic servomechanism adapted to be actuated by said template.

Claims

1. A gear grinder comprising a base; a grinding wheel; a head supporting the grinding wheel, saId head being mounted on said base so as to be movable in longitudinal and transverse direction of said base and pivotable with respect thereto; a worktable for supporting a workpiece to be ground into a gear, said table being mounted on said base so as to be movable in a vertical direction and rotatable within the required helix angle of the workpiece gear; a driving prime mover; a power transmission means for transmitting power from said prime mover to both the grinding wheel and the workpiece gear; and a crowning mechanism for effecting a crowning operation on the workpiece gear, said power transmission means including a first constant velocity universal joint associated with the grinding wheel head and a second constant velocity universal joint associated with said worktable, at least one of said universal joints being connected to a spur gear, said spur gear slidably engaging a pinion, whereby said spur gear slides along said pinion in response to either the vertical movement of the worktable or the movement of the grinding wheel head in the longitudinal and transverse directions of the base.