JP4468473B1 - Hobbing machine indexing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an indexing mechanism for maintaining a high-precision indexing process for a long period of time in a hobbing machine having an indexing mechanism composed of multi-row worm gears, by making use of familiar wear of worm gears to equalize adjacent pitches. .
SOLUTION: The number of teeth of the worm wheel 3 that meshes with the multi-worm worm 1 is set to the number of teeth that all the worm wheels mesh with all the worm wheel teeth while the worm wheel 3 rotates only several times. A conventional multi-worm worm gear that prevents the deterioration of indexing accuracy by equalizing adjacent pitches by combining the wear of only specific teeth for each number of worm lines of conventional means with equal wear of all teeth. . However, this multi-strip worm gear ratio is always a decimal value and is not suitable for the indexing mechanism. Therefore, the indexing constant is set to an integer value by absorbing or supplementing the fractional value of the decimal value in the transmission gear ratio in the mechanism. Thus, the calculation of the index change gear 7 is facilitated, and a means capable of indexing is provided.
[Selection] Figure 1

Description

  This invention is intended for gear cutting of small gears among hobbing machines equipped with an indexing mechanism composed of worm gears (referred to as a pair of worm and worm wheel). B4355) relates to an indexing mechanism of a hobbing machine (hereinafter referred to as “horizontal hobbing machine”) that uses a small hob having a size smaller than the specified size.

  Unlike a general vertical hobbing machine, the horizontal hobbing machine has a unique structure because the gear material 6 as a work material is relatively small and light as shown in FIG. That is, there is no table to which the gear material 6 that is a processed material is attached. Instead, a worm wheel shaft 4 is provided, a collet chuck 5 is provided at the tip, a gear material 6 or a material mounting shaft is fitted to the collet chuck 5, and a worm wheel shaft can be easily attached to the rear of the worm wheel shaft 4 with a tension screw. It is a structure that can be fixed to the axis 4. In addition, the hobbing machine using a small hob is generally horizontal because the replacement of the work material or the direction in which cutting oil or chips fall is convenient and the workability is good.

  Since the diameter of the hob 24 to be used is small in the horizontal hobbing machine, the hob shaft 23 rotates at a relatively high speed. Therefore, in the case of gear cutting with a small number of teeth, the worm shaft 2 rotates remarkably at high speed and there is a risk of burning due to sliding friction conduction. Therefore, the multi-worm worm 1 is composed of a plurality of worm strips, and the rotation speed and the rotational speed of the worm shaft 2 with respect to the rotation of the worm wheel 3 are reduced to a fraction of the worm strip to prevent the indexing mechanism from being worn. This multi-row worm 1 has a structure which only a horizontal hobbing machine with a small fluctuation load has.

  As a method of cutting out a gear, there is a forming gear cutting method in which an index base is mounted on a general-purpose milling machine, and a gear material is cut out one gear at a time by an involute tooth mill. This method is used, although it is inefficient when a special shape or accuracy is not required. However, with the increasing demand for gears and higher precision, various automatic processing machines dedicated to gear cutting have been developed. In other words, there are the hobbing method, rack cutter method, pinion cutter method, and the bevel gear method with G-shaped blades and the Gleason method special cutter. The main machining method is a unique motion mechanism, and gears that cannot be machined by other models can be efficiently and automatically geared up to completion. Hobbing machines are most commonly used because ordinary shaped spur gears, helical gears, and worm wheels can be machined with high efficiency by a hob.

  At present, the CNC control technology is rapidly developed, and various machine tools are made into NC. New multi-task machine tools have also been developed, and models with gear cutting functions are emerging. However, although it is multifunctional, the gears that can be machined are smaller than the size of the machine, and are small in productivity. Therefore, there is a drawback that it is a convenient but expensive gear. Therefore, they are not practical for mass production.

  In addition, there are NC processing machines that can automate the processing of complex shapes with NC machine tools and can demonstrate the effect by relying on human hands only for material replacement. In general, this is a machining method in which the rotation of the material or the tool is performed at a very high speed, and the use of a cemented carbide tool is mostly used. Therefore, the machining feed is slowed and no fluctuation load is generated. In the case of using a hobbing machine with an NC, since the hob is generating teeth, the load of fluctuation is large. Therefore, it is necessary to increase the rotation speed of the hob shaft and to make the feeding particularly slow. For this purpose, it is necessary to replace the expensive hob with a very expensive carbide hob. However, since the carbide hob is very fragile and the blade is easily damaged, if the rotation ratio of the biaxial motor loses the load and shifts slightly even during gear cutting, the load will increase rapidly and the carbide will instantaneously Hob blade is missing. Therefore, the problem of machining efficiency and profitability arises when the hobbing machine whose NC varies greatly depending on the shape and material of the machined gear.

  As a conventional gear cutting machine, in a gear cutting machine that rotates a work table in synchronization with the rotation of the gear cutting cutter and processes a work set on the work table, the work table is formed integrally with a motor to A gear cutting machine having a structure that directly rotates is proposed (see, for example, Patent Document 1). This is directly driven by a large motor 8, but there are many problems with the direct drive in order to accurately rotate the hobbing table with a large variable load. In addition, the screw shaft that moves the table saddle back and forth is located at the bottom for mounting the motor. The torsion causes the table saddle sliding surface to bend and wear, and it moves little by little due to fluctuating loads during processing, enabling accurate gear cutting. It becomes difficult.

  Moreover, in the conventional hobbing machine, cutting oil is used in order to remove the processing heat by cutting. Accordingly, the cutting oil falls on the table together with the chips. The outer periphery of the table is provided with a groove and is surrounded by a wall. Therefore, in order to fix the workpiece mounting shaft, it passes through the radially provided T groove and enters the oil tank provided in the bed from the large hole in the center. The structure is such that the cutting oil falls. Therefore, when the motor is located in the center, countermeasures are required. Accordingly, direct drive of the table is problematic in terms of torque, and there are many problems in machining capability in the case of NC hobbing machines with large variable loads.

  Therefore, another hobbing device has been proposed that includes a servo motor and a worm gear as a table driving mechanism (see, for example, Patent Document 2). The indexing mechanism of this type is driven by a worm gear by the servo motor. However, as can be seen from the drawings, the worm gear is separated from the sliding surface of the table, so there is a problem that the table is torsioned and accurate gear cutting cannot be performed.

  In addition, if a power failure occurs suddenly during gear cutting with an NC hobbing machine, the motor will also lose its electromagnetic holding power, so the 2-axis motor will withstand variable loads and simultaneously stop while maintaining the rotation ratio. Is difficult. Therefore, the hob blade is broken, the gear being processed, or the material mounting shaft is damaged. Therefore, in case of emergency, it is necessary to take measures against power failure such as installation of an uninterruptible power supply for power. Therefore, the conventional single-shaft hobbing machine, which has a stable structure due to many years of experience, can easily determine the limit of machining capacity based on the transmission gear noise, etc., and can increase production efficiency with peace of mind.

  Since it is most important that the hobbing machine can perform high-precision gear cutting, hobbing machine manufacturers increase the worm wheel diameter as much as possible within the machine structure and increase the number of teeth to improve indexing accuracy. Have made special efforts to maintain. However, it is necessary to rotate the gear material in synchronism with the cutting by the hob for generating teeth. Therefore, the intermittent cutting load by the hob is applied to the teeth of the worm wheel with sliding friction conduction, causing uneven wear and lowering the indexing accuracy. Therefore, when gear cutting is continuously performed on the same gear by heavy cutting, half of the gears are systematically shifted and the positions of the tooth tip and the tooth gap of the processed gear are switched. It is important to equalize uneven wear.

  Also, unlike spur gears, worm gears are completely sliding friction, so when there is no fluctuating load, the self-correcting function that equalizes adjacent pitches is strong, so the adjacent pitches become uniform due to familiar wear, and indexing accuracy Also recover. However, if the involute curve of the worm gear tooth surface is deformed due to wear, it cannot be corrected due to the familiar wear, so that an indexing error occurs for each number of worm wheel teeth. Therefore, hobbing machine manufacturers make worms with wear-resistant special steel, quench and harden to prevent tooth profile deformation, and prevent seizure with worm wheels.

  Among the horizontal hobbing machines, the micron hobbing machine, which is commonly used, has the largest processing capability and can cut gears. This hobbing machine was developed by Micron in Switzerland and has all the features of a horizontal hobbing machine, with a rational mechanism, a well-balanced gear ratio, and excellent operability. It is a board. Therefore, it has been popular since ancient times, and it is manufactured and used as a micron hobbing machine in various places. In addition, since the horizontal hobbing machine has a short machining cycle, there is a type in which the hob automatically returns to the position before machining after completion of gear cutting. There are types of micron hobbing machines equipped with an automatic return device.

Japanese Utility Model Publication No. 5-39827 Japanese Patent Publication No. 8-15686

  The problem to be solved by the present invention relates to an indexing mechanism for a horizontal hobbing machine. The horizontal hobbing machine has a multi-row worm composed of a plurality of worm strips, and each strip of the multi-row worm meshes only with a specific tooth of the worm wheel. Therefore, when uneven wear occurs due to gear cutting, each strip of the multi-row worm simply repeats wear with a specific tooth for each number of strips and does not cause an equalizing action with the adjacent pitch. For this reason, an indexing error that is a fraction of the number of teeth of the worm wheel occurs and does not disappear. Therefore, there is a negative effect that the indexing accuracy gradually decreases. An object of the present invention is to provide a horizontal hobbing machine that eliminates the adverse effects and maintains high-precision gear cutting over a long period of time.

  The means of the present invention for achieving the above object is to provide a horizontal hobbing machine having an indexing mechanism formed from a worm gear composed of a pair of a multi-row worm 1 and a worm wheel 3. The number of teeth added to the number of teeth that is a multiple of the number of worms 1 or the number of teeth that is reduced by 1 tooth is adjusted to the hobbing machine structure. In order to enable indexing from the multiple-worm worm gear ratio, which is a small band value, all the teeth of the multi-worm worm 1 shall mesh with all the teeth of the worm wheel 3 while the 3 rotates. In addition, a gear having a gear ratio that can absorb or supplement decimal fractions and eliminate decimals is provided between the indexing source shaft 10 and the hob shaft 23 of the indexing mechanism, and the indexing constant is an integer. To facilitate the calculation of the indexing gear as The deviation of rotation of the worm wheel 3 by tuning the rotation of the hob axis 23 is horizontal hobbing machine indexing mechanism being characterized in that to allow gear cutting.

  That is, the above-described indexing mechanism is configured such that the number of teeth of the worm wheel 3 meshing with the multi-row worm 1 is the same as the number of teeth of the worm wheel 3 while the worm wheel 3 is rotated several times. That is, the number of teeth with which the teeth of the worm wheel 3 are engaged is set. Therefore, when uneven wear occurs due to gear cutting, the worm wheel 3 of the present invention gradually equalizes adjacent pitches by sequentially shifting the familiar wear for each number of worm lines, so that all pitches are gradually made uniform. Indexing accuracy is restored. In addition, since the multi-worm worm gear has a larger lead angle than the single-worm worm gear, the meshing rate is improved like a helical gear. Therefore, the indexing error for each number of teeth generated in the single worm wheel is difficult to occur in the multi-row worm gear of the present invention, and smooth rotation can be maintained over a long period of time. However, such a multi-row worm gear is not suitable for the indexing mechanism because the gear ratio is always a decimal value. Therefore, since the means of the present invention requires an index constant of an integer value to calculate the index change gear 7, an arbitrary integer close to the decimal is used as an index constant, and the decimal of the difference from the integer is calculated. A gear having a gear ratio to be absorbed or supplemented is provided between the indexing mechanisms extending from the indexing source shaft 10 to the hob shaft 23.

  By using the above-described means of the present invention, it is possible to obtain an integer value index constant from the multi-row worm gear ratio of the decimal value, facilitate the calculation of the index change gear, and each time the multi-row worm gear rotates. In order to equalize the adjacent pitches of the worm wheels due to constant wear due to the disengagement of the gears, even if uneven wear due to gear cutting occurs, it gradually disappears, and high-precision indexing can be maintained over a long period of time. Therefore, the precision of gears and pinion gears made of thin sheet materials, which were difficult to improve in the secondary processing by shaving and gear grinding, has improved dramatically, and the quality of precision equipment that uses these small gears has improved. Therefore, the indexing mechanism of the present invention has an excellent effect not found in the conventional horizontal hobbing machine.

  Before describing the embodiment of the present invention, the indexing mechanism of the conventional horizontal hobbing machine will be described, and then the present invention will function as a hobbing machine as compared with the indexing mechanism of the horizontal hobbing machine according to the present invention. Explain that there is. Therefore, the most famous micron hobbing machine will be selected as the horizontal hobbing machine and will be described in comparison with an example to which the present invention is applied.

  First, the gear system diagram in the indexing mechanism of the micron type hobbing machine in FIG. 2 will be described. The multi-worm worm 1 is formed on a worm shaft 2 having 5 worms as one unit, and the worm wheel 3 meshing with the worm wheel 3 has 80 teeth and is provided on the worm wheel shaft 4. In FIG. 2, the number of teeth 80 is indicated as 80N, and in the drawing, N indicating the number of teeth is added after the numerical value. One end of the worm shaft 2 is exposed to the outside, and an index gear 7 can be attached. One end of the indexing source shaft 10 is also exposed to the outside, and the original shaft changing gear 9 can be attached. The indexing source shaft 10 and the hob shaft 23 have a one-to-one rotation ratio through a transmission shaft and gears inside the mechanism. Therefore, when the original gear change gear 9 and the index change gear 7 having the same number of teeth are attached to the index main shaft 10 and the worm shaft 2 and connected by the intermediate gear 8, the worm gear ratio is 16, so the hob shaft 23 rotates 16 times. Then, the indexing source shaft 10 rotates 16 times, and the worm shaft 2 further rotates 16 times. As a result, the worm wheel shaft 4 rotates once. That is, 16-division indexing can be performed.

  Therefore, the indexing constant of this micron type hobbing machine is 16. If the main shaft changing gear 9 having 16 teeth is attached to the indexing main shaft 10, the indexing gear 7 having the number of teeth to be indexed is warmed. If it is attached to the shaft 2 and connected by the intermediate gear 8, an indexing mechanism capable of indexing the target number of teeth is obtained. However, since the gear diameter is too small when the number of teeth of the original gear change gear 9 is 16, the original gear change gear 9 having 32 times the number of teeth is usually attached. In this case, the indexing gear 7 of the worm shaft 2 needs to be proportionally doubled in the number of teeth. Also, an original gear change gear 9 with 64 teeth is prepared for gear cutting with a small number of teeth. Therefore, the above index constant 16 is a reference value for calculating the number of teeth Z to be indexed of the index change gear 7.

  The main shaft changing gear 9 having the same number of teeth as the indexing constant 16 is attached to the indexing main shaft 10 of this micron type hobbing machine, and the indexing gear having the same number of teeth as the number Z of teeth to be indexed to the worm shaft 2 7 is connected by the intermediate gear 8 and the hob shaft 23 is rotated once, the rotation rate of the worm wheel shaft 4 is expressed by using the driving gear as the numerator and the driven gear as the denominator. This is the calculation formula (1). In this case, the intermediate gear and the gear having a meshing gear ratio of 1: 1 are omitted from the hob shaft 23 to the worm wheel shaft 4 because they do not affect the rotation ratio.

  As described above, the calculation formula (1) indicates that when the hob shaft 23 is rotated once, the worm wheel shaft 4 is rotated by 1 / Z. That is, since the hob shaft 23 rotates Z and the worm wheel shaft 4 rotates once, this is a mechanism capable of indexing the number of teeth Z of the indexing gear 7. Accordingly, the indexing gear 7 can be easily calculated.

  In this calculation formula (1), 1 is the number of rotations of the hob shaft 23, numerator 70 is the number of teeth of the gear 22 fixed to the hob shaft 23, and the denominator 35 is the teeth of the gear 21 fixed to the conduction shaft 14 c. Is a number. The next numerator 30 is the number of teeth of the helical gear 13 fixed to the conduction shaft 14 a, and the denominator 60 is the number of teeth of the helical gear 11 fixed to the indexing source shaft 10. The next numerator 16 is the number of teeth of the indexing constant of the main shaft changing gear 9 attached to the indexing main shaft 10, and the denominator Z is the number of teeth to be indexed of the indexing gear 7 attached to the worm shaft 2. . The next numerator 5 is the number of multiple worms 1 and the denominator 80 is the number of teeth of the worm wheel 3 fixed to the worm wheel shaft 4. Therefore, since the gear ratio of this multi-row worm gear is an integer value, the indexing error of 1/16 is not eliminated even by familiar wear.

  Next, an embodiment of the present invention will be described with reference to FIG. 1 as an example applied to the micron hobbing machine. By the way, the micron type hobbing machine has a reasonable structure and a well-balanced gear ratio. Therefore, the object of the present invention can be achieved by changing the number of teeth slightly without changing the structure of the micron hobbing machine as much as possible. Therefore, even when the indexing accuracy deteriorates due to the use of the conventional hobbing machine, there is an advantage that the hobbing machine can be regenerated into a highly accurate hobbing machine by simply replacing the gear of the present invention.

  That is, in the multi-row worm 1, the number of unit stripes remains 5 and the number of teeth of the worm wheel 3 is 80 to 81. Therefore, the meshing is adjusted by shifting the position of the multi-worm worm 1. In this way, since the number of teeth of the worm wheel 3 is 81, the meshing of the worm gear composed of the multi-worm worm 1 and the worm wheel 3 is sequentially shifted, and the worm wheel 3 is rotated five times so that all the elements of the multi-worm worm 1 are all. Will mesh evenly with the teeth of the worm wheel 3. For this reason, even if uneven wear occurs in the multi-row worm gear due to gear cutting, the worm wheel 3 does not generate the familiar wear for every five teeth, and the meshing is sequentially shifted, and the adjacent pitch is constantly equalized. It will become familiar and wear with each other. For this reason, all the pitches of the worm gears gradually become uniform. Further, since the multiple-worm worm gear has a larger advance angle than the single-worm worm gear, the meshing rate is increased like a helical gear. For this reason, it becomes difficult for the rotation error for every number of teeth of the worm wheel 3 to occur, and high-precision indexing can be maintained over a long period of time.

  However, in the case of a worm gear composed of the above-mentioned multi-row worm 1 and worm wheel 3, the gear ratio is 16.2 which is a decimal value. For this reason, the calculation of the indexing gear 7 becomes complicated, and it is not suitable for practical use as it is. Therefore, in the present invention, the helical gear 13 and the gears having a gear ratio that can absorb the fractional fraction 0.2 of the band decimal 16.2 between the indexing mechanism from the indexing source shaft 10 to the hob shaft 23. 21 is a means in which a gear 22 is provided and the indexing constant is set to an integer value of 16.

  That is, as shown in FIG. 1, the gear 22 fixed to the hob shaft 23 having the hob 24 at one end is replaced with a gear having 72 teeth, and the fixed gear 21 is connected to the conductive shaft 14c meshing with the gear 22 having 32 teeth. Replace with. Therefore, since the inter-shaft distance for one tooth is left, it is a positively shifted gear. Next, through a bevel gear 19 that meshes with the bevel gear 20 of the transmission shaft 14c, in the gear structure including the helical gear 17 of the transmission shaft 14b and the helical gear 16 and the helical gear 13 of the transmission shaft 14a. The helical gear 13 fixed to the transmission shaft 14a is replaced with a helical gear having 27 teeth. As a result of this replacement, an inter-axial distance of 1.5 teeth is left in the inter-axial distance between the helical gear 12 and the helical gear 13. However, the intermediate gear shaft 12a for adjusting the extra inter-shaft distance can be moved slightly to adjust the meshing. Further, since the intermediate helical gear 12 meshes with the helical gear 11 at a right angle, it is necessary to mesh with the center of the tooth width of the helical gear 11 as much as possible. Therefore, from the relationship of the meshing position with the new helical gear 13, the intermediate helical gear 12 is a gear having two more teeth. By doing so, the intermediate helical gear 12 meshes with the helical gear 13 and also meshes with the approximate center of the tooth width of the helical gear 11, so that the position of the intermediate gear shaft 12a is fixed. cure. The above is the means in which the indexing mechanism of the present invention is applied to a micron type hobbing machine. Note that the slide key groove 18 is formed in the fitting portion of the helical gear 16 of the transmission shaft 14a and the fitting portion of the helical gear 17 of the transmission shaft 14b. The gear 17 can slide while maintaining meshing.

  As described above, the present invention is a means using a micron hobbing machine, but the multi-worm worm gear ratio is a band decimal value, and is divided by the indexing gear 7 calculated as an integer constant of 16. The fact that the machining can be performed will be described by the following calculation formula (2). As shown in the above formula (1), the original shaft changing gear 9 having the same number of teeth as the new indexing constant 16 is attached to the indexing source shaft 10, and the worm shaft 2 has the same number of teeth as the number of teeth Z to be indexed. Are attached by an intermediate gear 8. Further, when the intermediate gear between the hob shaft 23 and the worm wheel shaft 4 and the gear with a gear ratio of 1: 1 are omitted, when the hob shaft 23 is rotated once, the driving gear is a numerator and the driven gear is a denominator. If the worm wheel shaft 4 is rotated by 1 / Z, the Z tooth number indexing gear 7 can perform gear cutting with the number of Z teeth. The conduction shaft 14a has a driving pulley 15 to transmit a driving force.

  The means of applying the indexing mechanism of the present invention to the micron type hobbing machine is as described above, and the multiple streak worm gear ratio is 16.2 which is a subordinate value. By making the number of teeth to be evenly engaged 81, the wear-in wear of every 5 teeth is changed to the adjacent pitch equalization direction, and the indexing mechanism that constantly improves the indexing accuracy of the worm wheel 3 by the wear-in wear. . However, when the multi-worm worm gear ratio is a small decimal value, it is difficult to calculate the indexing gear 7, which is inappropriate for the hobbing machine. Therefore, according to the means of the present invention, a gear having a gear ratio capable of absorbing 0.2 of a fraction is provided between the indexing mechanism from the indexing source shaft 10 to the hob shaft 23 as described above. This is a means that makes it easy to calculate the index change gear 7 with an integer value of 16 as an index constant and can maintain high-precision gear cutting over a long period of time.

  Since the horizontal hobbing machine has a relatively small indexing constant, the accuracy of the indexing gear greatly affects the machining accuracy via the worm gear. In the case of the indexing mechanism of the present invention, the error is distributed over the entire circumference of the machined gear, but the machining feed also proceeds simultaneously, resulting in a spiral stripe pattern and a reduction in tooth surface accuracy. Therefore, in order to perform gear cutting with high accuracy, it is necessary to use an indexing gear with good pitch accuracy obtained by performing secondary processing such as gear grinding on the indexing gear. In addition, when using a differential gear not shown in FIG. 1 to perform gear cutting, it is necessary to change the differential constant because rotation of one worm wheel is delayed. If it is not desired to change the conventional lead table, it is necessary to reduce the lead screw pitch 5 mm to 80/81.

  When a hobbing machine manufacturer manufactures a worm wheel that meshes with a multi-strip worm, it is necessary to use a hob dedicated to worm wheel gear cutting with the same diameter and the same strip as the multi-strip worm. Therefore, in the case of 80 micron-shaped worm wheel teeth, the index number of the mother hobbing machine is 16, not 80. Therefore, it is easy to make a pitch error every 5 teeth, and it is difficult to obtain an accurate worm wheel. Therefore, there is a worm wheel using a helical gear that can perform gear grinding. However, since it is in point contact with the multi-strand worm, there is a drawback that the friction pressure is increased and burnout is likely to occur. Since the worm wheel of the present invention has 81 teeth, a pitch error does not occur every five lines, and a highly accurate worm wheel can be obtained. However, since the index number is 16.2, an extra combination indexing gear of 81 teeth and 80 teeth is necessary to determine the fractional number.

  When the present invention is applied to a micron type hobbing machine, the conventional transmission gear was replaced and the purpose was achieved. However, when the structure is simpler with a horizontal hobbing machine of another model, an example in which the present invention is applied Is briefly explained. For example, in a horizontal hobbing machine in which the number of teeth of the worm wheel of the indexing mechanism is 30, the number of meshed multiple-worm worms is 3, and the indexing constant is 10, the distance from the indexing axis to the hob axis In the case of a hobbing machine having no transmission gear that can be replaced with the number of teeth of the invention, in order to apply the present invention, for example, if the number of teeth of the worm wheel is 29, the multi-worm worm gear ratio is 9.6666. Decimal. That is, the mixed number is 9 + 2/3. Therefore, in order to supplement 1/3 of the difference from 10, a transmission gear with 30 teeth is newly provided on the indexing source shaft side, and 29 transmission gears are provided on the hob shaft side. If an intermediate gear with an arbitrary number of teeth is provided and meshed to correct this, the conductive structure will be increased, but the adverse effects of the conventional multi-row worm gear can be eliminated and high precision gear cutting can be maintained for a long time.

FIG. 3 is a schematic perspective view of a gear system, excluding a differential device, of an indexing mechanism for a micron hobbing machine according to the present invention. It is a schematic perspective view of a gear system shown excluding a differential device among conventional indexing mechanisms of a micron hobbing machine.

Explanation of symbols

1 Worm shaft 2 Worm shaft 3 Worm wheel 4 Worm wheel shaft 5 Collet chuck 6 Gear material 7 Indexing gear Z Number of teeth of the indexing gear 8 Intermediate gear 9 Original shaft changing gear 10 Indexing shaft 11 HASUBA Gear 12 Intermediate helical gear 12a Intermediate gear shaft 13 Helical gear 14a Conductive shaft 14b Conductive shaft 14c Conductive shaft 15 Driving pulley 16 Helical gear 17 Helical gear 18 Slide keyway 19 Bevel gear 20 Bevel gear 21 Gear 22 Gear 23 Hob shaft 24 Hob

Claims (1)

In a horizontal hobbing machine that has an indexing mechanism formed from multi-row worms and worm wheels, the number of teeth of the worm wheel is set to a large number of teeth that can be accommodated in the hobbing machine structure, and the worm wheel rotates several times. During this time, the meshing of the multiple worms is shifted sequentially so that all the worms and all the worm wheel teeth are meshed evenly. Gears with a gear ratio that absorbs or supplements the fractional number of decimals from the multi-row worm gear ratio between the transmission shaft from the indexing shaft to the hob shaft to facilitate indexing and machining. An indexing mechanism for a horizontal hobbing machine, wherein the indexing constant is an integer value, and the hob shaft rotation is synchronized with the rotation deviation of the worm wheel.

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