JP6399740B2 - Gear mechanism - Google Patents

Description

  The present invention relates to a gear mechanism using a helical gear and capable of preventing backlash, and a gear cutting method for manufacturing a helical gear used in the gear mechanism.

In the gear mechanism, backlash has an unfavorable effect on driving force transmission at various points, and various mechanisms for preventing backlash have been conventionally considered.
For example, the gear mechanism disclosed in Patent Document 1 transmits a driving force between a drive shaft (plate cylinder shaft) and a driven shaft (impression cylinder shaft) in a multicolor printing printing apparatus in which backlash greatly impairs print quality. This is intended to prevent backlash.
As shown in FIG. 7, the gear mechanism is configured such that a driving side helical gear 137 that is driven integrally with the driving gear shaft 116, and this driving side meshes with the helical gear 137 to transmit a rotational force to the driven gear shaft 119. The driven side is a gear mechanism provided with a helical gear 139, and the driven side helical gear 139 is arranged on the outer periphery of the first helical gear 139 a integrated with the driven gear shaft 119 and the driven gear shaft 119. And a second helical gear 139b that is directly loosely fitted, and further, the second helical gear 139b is moved along the axial direction of the driven gear shaft 119 with respect to the first helical gear 139a. The guide pin 141 for guiding and a biasing means 148 for biasing the second helical gear 139b so as to be separated from the first helical gear 139a are provided.

A plurality of the guide pins 141 are arranged around the driven gear shaft 119. Each guide pin 141 is screwed to the first helical gear 139a by a bolt 142 at one end side thereof and the second helical tooth at the other end side. It penetrates through hole 143 provided in 139b.
Further, a plurality of through bolts 144 alternately with the guide pins 141 pass through the first helical gear 139a and are screwed into the female screw portion 145 formed in the second helical gear 139b, and the second helical gear. A lock nut 146 is screwed into the tip end portion of the through bolt 144 protruding from the gear 139b.
The compression coil spring 148 as the urging means surrounds the through bolt 144 in a recess 147 formed at the position of the through bolt 144 on the opposing surfaces of the first helical gear 139a and the second helical gear 139b. Is housed in. Therefore, the compression coil spring 148 urges the second helical gear 139b to be separated from the first helical gear 139a as described above. Reference numerals 138 and 140 denote keys. Reference numeral 150 denotes a thrust bearing, and reference numeral 151 denotes a nut that engages with the male thread portion 149 of the driven gear shaft 119.

  When assembling the gear mechanism, the second helical gear 139b on the driven side is aligned with the tooth trace of the first helical gear 139a and the spring force of the compression coil spring 148 is applied. The gap G is set between the head of the through bolt 144 and the first helical gear 139a so that the backlash can be removed sufficiently. This setting is synonymous with the initial setting so that the gap between the two gears 139b and 139a is the distance C when both the gears 139b and 139a are aligned, but in the initial setting to set the distance C, Thrust bearing 150 and nut 151 are used. After the initial setting of the thrust bearing 150 and the nut 151 is completed, the thrust bearing 150 and the nut 151 are detached from the driven gear shaft 119 so that the second helical gear 139b can be moved rightward in the drawing by the spring force of the compression coil spring 148. To do.

In the above gear mechanism, the second helical gear 139b on the driven side is biased in the direction away from the first helical gear 139a by the spring force of the compression coil spring 148. There is no backlash between the helical gear 137 and the driven side helical gear (the first helical gear 139a and the second helical gear 139b) 139.
In the case where the gear mechanism is applied to a printing apparatus, when the thickness of the printing medium (web) changes, the plate cylinder shaft (drive shaft) 116 and the impression cylinder shaft (drive cylinder shaft 116 and the impression cylinder shaft) are changed according to the thickness of the printing medium. The second helical gear 139b on the driven side moves in a direction away from the first helical gear 139a in accordance with the distance between the shaft and the driven shaft 119 (that is, the distance between the gear centers) (initially set gap). C) from the position C), and the backlash between the helical gear 137 on the driving side and the helical gear 139 (139a, 39b) on the driven side is eliminated. That is, the backlash is automatically resolved.

JP2002-188708

In the gear mechanism 110 described above, as a structure for automatically eliminating backlash, a guide pin 141 for moving and guiding the second helical gear 139b in the axial direction with respect to the first helical gear 139a is provided. Further, as a biasing means for separating the second helical gear 139b from the first helical gear 139a, a compression coil spring 148, a through bolt 144, a recess 147, a lock nut 146, and the like are provided. In addition, in order to appropriately adjust the gap G provided between the head of the through bolt 144 and the first helical gear 139a, a structure in which the thrust bearing 150 and the nut 151 are provided is necessary. As complicated as. Further, the first helical gear 39a and the second helical gear 39b on the driven side are separately manufactured and assembled on the driven gear shaft 119.
In addition, with such a complicated structure, and the structure in which the first helical gear 139a and the second helical gear 139b on the driven side are separately manufactured and assembled, Secondly, the mechanical strength of the helical gear 139b is low, and it seems that it cannot be applied to sufficiently large driving force transmission. Further, since the structure is complicated, the production becomes complicated and the cost increases. Further, the operation of setting the gap G using the thrust bearing 150 and the nut 151 is also complicated.

  The present invention has been made to eliminate the above-mentioned conventional drawbacks, and in a gear mechanism using a helical gear, the occurrence of backlash can be prevented with a simple structure, and the stationary driven gear and the movable driven gear are divided. It is an object of the present invention to provide a gear mechanism that can easily assemble a driven gear, has good workability, has high mechanical strength, can be easily manufactured, and can reduce its cost. It is another object of the present invention to provide a gear-cutting method capable of gear-cutting a fixed driven gear and a movable driven gear with high accuracy, efficiency, and low cost.

The invention of claim 1 that solves the above-described problem is any of a driving gear driven by a driving shaft and a driven gear that is provided on a driven shaft as an output shaft parallel to the driving shaft and meshes with the driving gear. A gear mechanism using a helical gear,
The driven gear integrally includes a sleeve portion that extends toward the shaft end of the driven shaft, and a driving force that meshes with the drive gear in a state in which movement of the sleeve portion in the axial direction is restricted by the driven shaft. A fixed driven gear for transmission, and a movable driven gear for preventing backlash that is fitted to the sleeve portion of the fixed driven gear and is movable only in the axial direction and meshes with the drive gear,
A fixed member that is attached to the shaft end portion of the driven shaft and that abuts only the end surface of the sleeve portion and restrains the axial movement of the fixed driven gear; and the movable driven gear is attached to the fixed driven gear side. it characterized by comprising biasing means for energizing.

According to a second aspect of the present invention, in the gear mechanism according to the first aspect, the fixed driven gear is fitted to a small diameter portion formed with a step on the end side of the driven shaft, and the stepped portion and the fixing member The movement in the axial direction is restricted by the above.

According to a third aspect of the present invention, in the gear mechanism according to the first or second aspect, the drive gear and the driven gear are gear mechanisms capable of responding to variations in the distance between the centers of the gears.

  According to a fourth aspect of the present invention, in the gear mechanism according to any one of the first to third aspects, the urging means houses a compression coil spring in a recess provided on a side surface of the movable driven gear opposite to the fixed driven gear. And a headed bolt that is inserted through the compression coil spring, penetrates a through hole formed in the bottom surface of the recess, and is screwed into a screw hole provided on a side surface of the fixed driven gear. It is characterized by comprising.

According to a fifth aspect of the present invention, in the gear mechanism according to any one of the first to fourth aspects, the fixed driven gear is coupled to the driven gear shaft through a first key so as to be integrally rotatable, and the movable driven gear is a first gear. It is characterized in that it is slidably connected in the axial direction to the sleeve portion through two keys so as to be integrally rotatable.

A sixth aspect of the present invention is the gear mechanism according to any one of the first to fourth aspects, wherein the lower roll 20 is fixed to the lower roll shaft 1A having the end portion of the drive gear shaft 1 in the cold roll forming machine. In the roll forming machine, the upper roll 21 is fixed to the upper roll shaft 3A having the driven gear shaft 3 at the end, and the band steel sheet is fed between the rotating upper and lower rolls 20, 21 to form irregularities on the band steel sheet. Any of a gear mechanism that is driven by the drive gear shaft 1 and a driven gear that is provided on a driven gear shaft as an output shaft parallel to the drive gear shaft and meshes with the drive gear. It is a gear mechanism using a helical gear.

In the present invention, when backlash occurs, the movable driven gear approaches the fixed driven gear side by the spring force, so that the backlash is automatically eliminated. Since the spring force always acts on the movable driven gear, the occurrence of backlash can be prevented.
A spring having an urging force to which a certain amount of spring force acts in an aligned state in which the tooth trace of the movable driven gear is aligned with the tooth trace of the fixed driven gear is used. When the driven gear assembled using such a spring is meshed with the drive gear, a gear mechanism in which the backlash is prevented can be obtained.

As described above, it is sufficient to use a spring having an appropriate biasing force as a spring, and no complicated initial setting is required. Therefore, the assembly work of the driven gear is extremely easy as compared with Patent Document 1, and the workability is good. It is.
If the biasing force of the spring is not appropriate, the spring is replaced immediately after the headed bolt is removed because the recess for housing the spring is on the side of the outer side of the movable driven gear (the side opposite to the fixed driven gear). In this respect, workability is good. In Patent Document 1, since the spring is inside the movable driven gear, it is necessary to replace the spring after removing the lock nut, removing the through bolt and sliding the movable driven gear to widen the distance from the fixed driven gear. The replacement of the spring is complicated.

  In the present invention, as a mechanism for preventing backlash, a recess is formed in the outer side surface of the movable driven gear, a through hole is formed in the bottom surface, a spring is accommodated in the recess, and a headed bolt that passes through the spring is provided. It is realized with a simple configuration of being screwed into a screw hole formed on the fixed driven gear side, and is simpler than that of Patent Document 1 having a complicated structure. Therefore, it is easy to manufacture and can be manufactured at low cost.

  The movable driven gear is not directly fitted to the driven shaft, but is fitted to a large-diameter sleeve portion formed on the fixed driven gear. Unlike helical gears, it can be said that the strength is high against axial forces. In addition, since sliding is performed on the large-diameter sleeve portion, there is no fear of tilting during the sliding, and smooth sliding is possible.

  When gearing of the fixed driven gear and the movable driven gear is performed, the gear material for the movable driven gear is fitted to the sleeve portion of the gear material for the fixed driven gear instead of individually gearing the two. Since both gears can be cut in the state, gear cutting can be performed with high accuracy, gear cutting can be efficiently performed, and processing can be performed at low cost.

It is sectional drawing which abbreviate | omitted partially showing the gear mechanism of one Example of this invention. It is a B arrow view of FIG. 1 (however, a drive shaft is shown with a cross section). It is a figure which shows the case where the said gear mechanism is applied to the drive force transmission mechanism between the upper and lower roll shafts in a cold roll forming machine. FIG. 2 is a diagram schematically illustrating the meshing state of teeth of a driving gear and a driven gear (a fixed driven gear and a movable driven gear) in the gear mechanism (corresponding to an enlarged cross-sectional view taken along line AA in FIG. 1); B) When the movable driven gear and the fixed driven gear are aligned (with the tooth traces of both gears aligned) in a state where a thin steel sheet of thickness t1 is sandwiched between the upper and lower rolls, When the backlash is automatically eliminated from the aligned state (a) with rush, (c) is the case where a steel plate having a thickness t2 thicker than the plate thickness t1 is sandwiched, and the automatic backlash is eliminated. The state with the backlash just before being performed, (d) shows the case where the backlash is automatically resolved from the state with the backlash (c). It explains the point of gear cutting of the driven gear (fixed driven gear and movable driven gear) in the above gear mechanism, (a) is a partially omitted front view, (b) is a right side view of (b). (However, the interval regulating bolt is shown in cross section). The other Example of this invention is shown typically, (A), (B), (C) shows a different Example, respectively. It is sectional drawing which shows the conventional gear mechanism.

Hereinafter, modes for carrying out the gear Organization of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a gear mechanism according to an embodiment of the present invention, in which a part of the gear mechanism is omitted, and FIG.
The gear mechanism 10 includes a drive gear 2 that is driven integrally with a drive gear shaft 1 that is rotationally driven by a drive shaft, and a driven gear 4 that meshes with the drive gear 2 and transmits a rotational force to the driven gear shaft 3. Become. Both the drive gear 2 and the driven gear 4 are helical gears, and a shift gear is used so as to cope with fluctuations in the distance between the upper and lower gear centers. Reference numeral 15 denotes a driving shaft, and 16 denotes a chain coupling connected to the drive gear shaft 1.
The driven gear 4 includes a fixed driven gear 5 and a movable driven gear 6. The fixed driven gear 5 has a sleeve portion 5a extending toward the movable driven gear 6 side. Further, the fixed driven gear 5 is coupled to the driven gear shaft 3 through a key 7 so as to rotate integrally therewith, and is attached to the shaft end of the driven shaft 3 by a bolt 13 with a disc-shaped end plate (fixed). The movement in the axial direction is constrained by a member 8 and is fixed to the driven shaft 3. The fixed driven gear is fitted to a small diameter portion formed with a step on the end side of the driven shaft 3 as shown in FIG. 1, and the step (step portion) and the end The movement in the axial direction is restricted by the part plate (fixing member) 8.
The movable driven gear 6 is slidably fitted to the sleeve portion 5a of the fixed driven gear 5 and is coupled to the fixed driven gear 5 in the rotational direction via a key 9 so as to be fixed to the fixed driven gear 5. It can be moved only in the axial direction.

  On the side surface of the movable driven gear 6 opposite to the fixed driven gear 5 side, recesses 6a are formed at a plurality of locations spaced in the circumferential direction, and axial through holes 6b are formed on the bottom surface of the recesses 6a. It has been opened. A screw hole 5b is formed at the front side of the through hole 6b on the side surface of the fixed driven gear 5 on the movable driven gear 6 side. A compression coil spring 11 as an urging means for urging the movable driven gear 6 toward the fixed driven gear 5 is accommodated in the recess 6a. The compression driven spring 11 passes through the compression coil spring 11 and penetrates the through hole 6b. A headed bolt 12 into which the tip screw portion is screwed into the screw hole 5b of the gear 5 is provided. In FIG. 1, only one portion of the headed bolt 12 is shown and the other parts are omitted.

FIG. 3 is a diagram showing a case where the gear mechanism 10 is applied to a driving force transmission mechanism between upper and lower roll shafts in a cold roll forming machine.
In the illustrated example, an embossed steel sheet in which a large number of irregularities are formed on a thin steel sheet of 0.3 mm to 0.8 mm, for example, is manufactured by a roll forming machine, and the drive gear shaft 1 portion is at the end. A lower roll (lower embossing roll) 20 is fixed to the lower roll shaft 1A, an upper roll (upper embossing roll) 21 is fixed to an upper roll shaft 3A having the driven gear shaft 3 at the end, and the upper and lower rolls rotate. An embossed steel plate is manufactured by feeding a strip steel plate (band-shaped transfer material) between 20 and 21 and forming a large number of irregularities on the strip steel plate. The embossed steel sheet fed from the roll forming machine is cut into a predetermined length by a cutting machine. 22 and 23 are roll stands that support the upper and lower roll shafts on both sides of the emboss rolls 20 and 21 with, for example, cylindrical roller bearings.
The concave and convex shapes of the upper and lower rolls 20 and 21 are opposite to each other. If the rotational speeds of the upper and lower rolls 20 and 21 do not coincide with each other with high accuracy, the irregularities of the upper and lower rolls are misaligned, resulting in a precise concave and convex shape. I can't get it. Therefore, a roll forming machine (transfer device) that forms the embossed steel sheet by incorporating the upper and lower embossing rolls 20 and 21 needs to make the rotational speeds of the upper and lower roll shafts coincide with each other accurately. The gear mechanism 10 that transmits force needs to prevent backlash with high accuracy.

When assembling the gear mechanism 10, the movable driven gear 6 is fitted into the sleeve portion 5 a of the fixed driven gear 5, the compression coil spring 11 is accommodated in the recess 6 a of the movable driven gear 6, and the headed bolt 12 is connected to the compression coil spring 11. A driven gear in which the fixed driven gear 5 and the movable driven gear 6 are integrated by passing the inside through the through hole 6b on the bottom surface of the recess and screwing the tip screw portion into the screw hole 5b on the side surface of the fixed driven gear 5. (Fixed driven gear 5 and movable driven gear 6).
Next, after the integrated driven gear (fixed driven gear 5 and movable driven gear 6) 4 is inserted into the driven gear shaft 3 and meshed with the drive gear 2, the end plate 8 is connected to the shaft end surface of the driven shaft 3. The gear mechanism 10 is assembled by fixing it with the bolts 13. The order of assembly can be partially changed.

The length of the headed bolt 11, the depth of the recess 6a, and the elastic coefficient and length of the compression coil spring are appropriately set. FIG. 1 shows an aligned state in which the driven gear 4 (the fixed driven gear 5 and the movable driven gear 6) is engaged with the drive gear 2 and the tooth traces of the movable driven gear 6 and the tooth traces of the fixed driven gear 5 are aligned. cage, showing the clearance between the stationary driven gear 5 and the movable driven gear 6 in this alignment by C _0. In this aligned state, the movable driven gear 6 receives an appropriate spring force (a spring force capable of moving the movable driven gear 6 to eliminate backlash) from the compression coil spring 11. In FIG. 1, the outer side surface of the movable driven gear 6 (the side opposite to the fixed driven gear 5) and the end surface of the sleeve portion 5 a of the fixed driven gear 5 are aligned, but it is not always necessary to align them.
Note that the outer diameter of the end plate 8 can be made larger than the inner diameter of the movable driven gear 6 so that the peripheral edge can hit the outer side surface of the movable driven gear 6. In this case, in a state where the outer side surface of the movable driven gear 6 hits the end plate, clearance may be such that said alignment when clearance C ₀ when the proper spring force is caused.

In the gear mechanism configured as described above, an operation of automatically eliminating backlash will be described. In an aligned state where the teeth of the fixed driven gear 5 and the movable driven gear 6 are aligned, backlash occurs between the drive gear 2 and the driven gear 4 (the fixed driven gear 5 and the movable driven gear 6). When the movable driven gear 6 moves parallel to and approaches the fixed driven gear 5 side by the spring force from this aligned state, the tooth traces of the two gears 5 and 6 are displaced from each other. Since the tooth traces of the two gears 5 and 6 are shifted from each other, the tooth thickness at the meshing contact point position of the driven gear 4 composed of the two gears 5 and 6 is substantially meshed with the driving gear 2. The groove width W at the point position is expanded (substantially the same as when the driven gear tooth profile is manufactured with zero backlash in terms of meshing action), and backlash is eliminated.
In this case, the number of teeth that are involved in meshing with the drive gear at the same point (contact with the teeth of the drive gear) differs depending on the torsion angle of the gear, the width of each gear 5, 6 (width in the axial direction), and the like. For example, two teeth or three teeth are in contact with each other at the same time. However, since it is a helical gear and the tooth traces are inclined, the meshing contact points are moved in a plurality of tooth traces. A driven action and a backlash elimination action are produced, and a rotational force transmission without backlash is performed.

FIG. 4 shows the concept of the above-described backlash prevention action, in which the driven gear 4 (the fixed driven gear 5 and the movable driven gear 6) is designed to prevent backlash by one tooth trace in one tooth groove of the drive gear 2. It is a figure which simply formulates and demonstrates that it is driving while driving. Note that FIG. 4 substantially corresponds to the AA cross section of FIG.
FIG. 4 (a) shows a case in which the stationary driven gear 5 and the movable driven gear 6 are in an aligned state (a state in which the tooth traces of both gears are aligned) in a state where a thin steel sheet t1 is sandwiched between upper and lower rolls. The meshing state is schematically shown. Reference numeral 2d denotes teeth of the drive gear 2, 5d denotes teeth of the fixed driven gear 5, and 6d denotes teeth of the movable driven gear 6.

In the aligned state shown in FIG. 4 (a) (the state in which the tooth traces of both gears are aligned and the backlash correction operation is not performed), backlash occurs, but the compression coil spring 11 that is constantly acting The movable driven gear 6 is moved by δC in the direction approaching the fixed driven gear 5 (arrow n direction) by the spring force, and the tooth traces of both gears 5 and 6 are shifted from each other. Since the tooth traces of the two gears 5 and 6 are shifted from each other, the tooth thickness at the meshing contact point position of the driven gear 4 composed of the two gears 5 and 6 is substantially meshed with the driving gear 2. The groove width W at the point position is expanded (substantially the same as when the driven gear tooth profile is manufactured with zero backlash in terms of meshing action), and backlash is eliminated. As shown in FIG. 4B, backlash is eliminated. It shows the clearance at this time in C _1.

When a steel plate having a thickness t2 larger than the thickness t1 is sandwiched between the upper and lower rolls, the distance between the upper and lower roll shafts (= the distance between the drive gear shaft 1 and the driven gear shaft 3), that is, between the centers of the upper and lower gears. Since the distance increases, the tooth thickness at the meshing portion becomes thin as shown by the broken line in FIG. 4B, that is, as shown by the solid line in FIG. 4C, and a backlash occurs. In this case, similarly to the above, the movable driven gear 6 moves in the direction approaching the fixed driven gear 5 (in the direction of the arrow n ′) by the spring force of the compression coil spring 11 that is constantly acting, The tooth traces deviate from each other, and the tooth thickness at the meshing contact point position of the driven gear 4 consisting of the two gears 5 and 6 as shown in FIG. The backlash is eliminated by extending the groove width W ′ at the contact point position. It shows the clearance at this time in C _2. The tooth thickness W ′ at this time is slightly smaller than the tooth thickness W.

As described above, in the gear mechanism of the present invention, when backlash occurs, the movable driven gear 6 approaches the fixed driven gear 5 side by the spring force of the compression coil spring 11, so that the backlash is automatically eliminated. The Since the spring force of the compression coil spring 11 always acts on the movable driven gear 6, the occurrence of backlash can be prevented.
As the compression coil spring for eliminating the backlash, a compression coil spring having an appropriate urging force may be used, and no complicated initial setting is required. Therefore, the assembly work of the driven gear 4 is extremely easy as compared with Patent Document 1. Workability is good.
If the urging force of the compression coil spring is not appropriate, the recess 6a for accommodating the compression coil spring is located on the outer side surface of the movable driven gear 6, so that the compression coil spring 11 can be replaced immediately after the headed bolt 12 is removed. In this respect, workability is good. On the other hand, in Patent Document 1, since the spring is inside the movable driven gear, the lock nut is removed, the through bolt is pulled out, the movable driven gear is slid to widen the space between the fixed driven gear and the spring is replaced. It is necessary to do this, and changing the spring is complicated.

In the present invention, as a mechanism for preventing backlash, a recess 6a is formed in the outer side surface of the movable driven gear 6, a through hole 6b is formed in the bottom surface, and the spring 11 is accommodated in the recess 6a. This is realized by a simple configuration in which the headed bolt 12 is screwed into a screw hole opened on the fixed driven gear 5 side, and is simpler than that of the patent document 1 having a complicated structure, and therefore easy to manufacture. Can be manufactured inexpensively.
The movable driven gear 6 is not directly fitted to the driven gear shaft 3, but is fitted to a large-diameter sleeve portion 5a formed on the fixed driven gear 5, so that the movable driven gear 6 is directly fitted on the thin driven gear shaft. Unlike the first helical gear 1, it can be said that the strength is high with respect to the axial force. Further, since sliding is performed on the large-diameter sleeve portion 5a, there is no risk of tilting during the sliding, and smooth sliding is possible.

The procedure for gear cutting of the fixed driven gear 5 and the movable driven gear 6 of the driven gear 4 will be described.
In FIG. 5, 5 'indicates a gear material for a fixed driven gear, and 6' indicates a gear material for a movable driven gear. Here, the gear material refers to a material that becomes a desired gear when gear cutting is performed. Therefore, the width of the gear members 5 ′ and 6 ′ is the width of the gear to be obtained, and the shaft hole is formed. Further, a sleeve portion 5a ′ is already formed on the gear member 6 ′ for the fixed driven gear.
The gear cutting is performed from the outer diameter of the sleeve portion of the gear member 5 ′ for the movable driven gear and the gear member 5 ′ for the fixed driven gear fitted to the sleeve portion 5a ′ of the gear member 5 ′ for the fixed driven gear. The gear material 5 ′ for the fixed driven gear and the gear material 6 for the movable driven gear with the gap S between the outer portion and the preset clearance C ₀ (clearance in the aligned state) set to the same dimensions. Perform gear cutting for 'and.

In this case, screw holes 6e 'are formed in, for example, four circumferentially equidistant positions on the side surface of the gear member 6' for the movable driven gear, and the distance regulating bolt 25 is screwed into the screw hole 6e 'to fix the tip. The size of the gap S (= C ₀ ) is defined by abutting against the side surface of the gear member 5 ′ for the driven gear.
As described above, when gear cutting of the fixed driven gear 5 and the movable driven gear 6 is performed, the gear material 6 ′ for the movable driven gear is used as the gear material for the fixed driven gear, instead of gearing the two separately. Since both gears can be cut in a state of being fitted to and integrated with the 5 'sleeve portion 5a', accurate gear cutting can be performed, and gear cutting can be efficiently performed. Can be processed at low cost.
It should be noted that the gap regulating bolt 25 is loosened as necessary. Further, means for restricting the direction in which the two gear members 5 ′ and 6 ′ are separated may be provided on the machine tool side for gear cutting.

In the above-described embodiment, the movable driven gear 6 is fitted to the sleeve portion 5a formed integrally with the fixed driven gear 5. However, as shown in FIG. 6 (a), the fixed driven gear 5A is not provided with a sleeve portion. The movable driven gear 6 </ b> A may be directly fitted to the driven gear shaft 3.
Further, as shown in FIG. 6B, the fixed driven gear 5B may be provided on the shaft end side of the driven gear shaft 3.
Further, as an urging means for urging the movable driven gear toward the fixed driven gear side, the screw portion at the tip of the headed bolt is not screwed into the screw hole on the fixed driven gear side, but as shown in FIG. It can also be configured. That is, a through hole is not provided in the bottom surface of the recess 6Ca that accommodates the compression coil spring 11, and the end plate 8C is formed into a stepped disk shape integrally including a large-diameter flange portion 8Ca, and the end plate 8C The screw portion of the headed bolt 12C is screwed into the screw hole 8Cb provided in the flange portion 6Ca, and the tip side thereof is brought into contact with the bottom surface of the recess 6Ca through the compression coil spring 11 disposed in the recess 8Ca. You can also.

1 drive gear shaft 2 drive gear,
3 driven gear shaft 4 driven gear 5 fixed driven gear 5a sleeve portion 5b screw hole 6 movable driven gear 6a recess 6b through hole 6e screw hole 7 key 8 end plate (fixing member)
9 Key 10 Gear mechanism 11 Compression coil spring 12 Head bolt 15 Drive shaft 16 Chain coupling 20 Lower emboss roll 21 Upper emboss roll 22, 23 Roll stand 25 Spacing bolt

Claims (6)

Each of these is a gear mechanism using a helical gear, including a driving gear driven by a driving shaft and a driven gear provided on a driven shaft as an output shaft parallel to the driving shaft and meshing with the driving gear. And
The driven gear integrally includes a sleeve portion that extends toward the shaft end of the driven shaft, and a driving force that meshes with the drive gear in a state in which movement of the sleeve portion in the axial direction is restricted by the driven shaft. A fixed driven gear for transmission, and a movable driven gear for preventing backlash that is fitted to the sleeve portion of the fixed driven gear and is movable only in the axial direction and meshes with the drive gear,
A fixed member that is attached to the shaft end portion of the driven shaft and that abuts only the end surface of the sleeve portion and restrains the axial movement of the fixed driven gear; and the movable driven gear is attached to the fixed driven gear side. A gear mechanism comprising biasing means for biasing. The fixed driven gear is fitted to a small diameter portion formed with a step on the end side of the driven shaft, and axial movement is restricted by the step portion and the fixing member. The gear mechanism according to claim 1.   The gear mechanism according to claim 1 or 2, wherein the drive gear and the driven gear are gear mechanisms that can cope with fluctuations in the distance between the centers of the gears.   The biasing means accommodates a compression coil spring in a recess provided on the side surface of the movable driven gear opposite to the fixed driven gear, and has a through hole formed in the bottom surface of the recess through the compression coil spring. The head bolt which penetrated and screwed the front-end | tip thread part in the screw hole provided in the side surface of the said fixed driven gear was provided, and it comprised, The structure of any one of Claims 1-3 characterized by the above-mentioned. Gear mechanism.   The fixed driven gear is coupled to the driven gear shaft via a first key so as to be rotatable integrally with the driven gear shaft, and the movable driven gear is slidable in the axial direction and rotatable integrally with the sleeve portion via a second key. The gear mechanism according to any one of claims 1 to 4, wherein the gear mechanism is coupled. The gear mechanism fixes the lower roll to the lower roll shaft having the end portion of the drive gear shaft in the cold roll forming machine, and fixes the upper roll to the upper roll shaft having the end portion of the driven gear shaft. A gear mechanism in a roll forming machine that feeds a strip between upper and lower rotating rolls to form irregularities on the strip, the drive gear being driven by the drive gear shaft, and the output parallel to the drive gear shaft 6. The gear mechanism using a helical gear according to any one of claims 1 to 5, wherein the driven gear is provided on a driven gear shaft as a shaft and meshes with the drive gear. The gear mechanism described.

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