JP5551950B2 - Helical gear machining method - Google Patents

Description

  The present invention relates to a helical gear machining method, and in particular, to determine whether or not the machining specification has a high probability of generating ghost noise, and to adjust the cutter feed rate to suppress ghost noise. Regarding the method.

When creating a tooth surface of a gear, a tooth profile is formed in a gear cutting step of cutting the gear blank material while relatively moving the gear blank material and the cutting tool. As the cutting tool, a hob cutter, a pinion cutter or the like is used.
When machining with a combination of a gear blank and a cutting tool, generally the final tooth profile will not be obtained, and since a minute scaly process mark will remain on the tooth surface due to each so-called tool mark, the tooth surface will be finished. A process is required. In this tooth surface finishing process, tooth surface finishing is performed by gear grinding using a shaving cutter or a screw-type grindstone to improve tooth surface roughness, ensure tooth surface accuracy, and reduce gear noise.

  Here, normal gear noise is generally generated at a gear meshing order and an integer multiple thereof, and is perceived as sound or vibration, but noise generated at a non-integer multiple of the gear meshing order is a so-called ghost sound. Good, gives a sense of discomfort to normal gear sound. Therefore, in order to suppress a ghost sound, a technique for improving the surface roughness by grinding the tooth surface is known (for example, Patent Document 1).

  Further, by collecting vibration data of the rotating body and performing frequency analysis, it is possible to determine whether the gear is engaged or not (for example, Patent Document 2), or each of the plurality of simultaneous contact line directions of the gear is measured by measuring the surface shape. A technique is known in which the tooth surface shape of a helical gear is measured by setting the meshing direction based on the apex of the actually measured tooth surface shape (for example, Patent Document 3).

JP 2000-52145 A JP-A-2-38930 Japanese Patent Laid-Open No. 11-118407

However, Patent Document 1 is a processing technique for eliminating a ghost sound by tooth surface grinding of a gear that generates a ghost sound, and does not focus on the problem of suppressing the ghost sound in a gear cutting process by a cutter.
Patent Document 2 and Patent Document 3 disclose measurement and analysis techniques for tooth surface shapes, and there is no problem of creating a gear cutting processing specification with a cutter for suppressing the occurrence of ghost noise. Not disclosed.

  The present invention has been made in view of such a background, and determines whether or not the machining specification has a high probability of generating a ghost sound, and adjusts the feed speed of the cutter to suppress the ghost sound. It is an object of the present invention to provide a gear machining method.

In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that the number of teeth of a helical gear is Z, the number of cutters cutting the tooth surface of the gear is H, an arbitrary positive integer is N, and the balance When the integer part is M, Z = H × N1 + M, and when N1 is set so that the absolute value of M is the smallest, it is determined whether or not any of M = ± 1 is satisfied. A gear processing method comprising: a specification determining step; and a gear cutting step for gear cutting with a combination of the number of teeth Z and the number of threads H satisfying any one of M = ± 1, and the width direction of the gear set 1 tooth meshing length corresponding δ in the direction along the, the feed pitch of the cutter with respect to one revolution per the gears as Vf (rotation mm / gear) formed in the one tooth meshing length corresponding δ The tool mark number T of the cutter , T ′ = δ / Vf, and rounding off from T ′ = δ / Vf, the tool mark number calculation step is obtained as an integer. The gear cutting step is expressed as T = N2 × H + K, where N2 is an arbitrary natural number and K is the remaining integer part. At this time, the feed pitch Vf that does not satisfy T = N2 × H + 1 or T = N2 × H−1 is set and gear cutting is performed.

  According to the first aspect of the invention, there is a high possibility that a ghost sound is generated by including a specification determination step for determining whether or not M = ± 1 is satisfied, expressed as Z = H × N1 + M. When it is determined whether or not the machining specifications are satisfied and there is a high possibility that a ghost sound is generated, a means for suppressing the ghost sound can be incorporated in the machining process in advance.

  That is, when the tool mark of the cutter formed on the tooth surface of the gear is verified in the combination of the number of teeth Z and the number of stripes H satisfying any one of M = ± 1, it is sequentially performed along the feed direction of the cutter. , Tool marks formed by adjacent blade portions (individual cutters from the first line to the H line) having different line numbers are arranged.

  On the other hand, since the center axis is eccentric as an individual difference or the center axis is displaced when it is attached to the gear cutting machine, the cutter inevitably occurs within the allowable limit of machining accuracy. Under the influence of the above, it is assumed that the blade portions (tooth portions from the first line to the H line) of the respective line numbers form tool marks having slightly different cutting depths.

  Then, the eccentricity of the shaft is affected by the difference in the cutting depth of the tool mark formed by the tooth part of the adjacent line number in a cutter with a large number of lines, so that it is adjacent to the tooth surface one by one. When the tool marks having the line numbers are arranged, tool marks having slightly different cutting depths are continuously arranged, so that a swell having continuous smooth regularity is formed on the tooth surface. Further, the effect of the undulation on the ghost sound will be described later.

  In this way, by determining whether or not M = ± 1 is satisfied, is it highly likely that swells having continuous smooth regularity that affects the ghost sound are formed on the tooth surface? If the processing specifications are such that the undulation that affects the generation of the ghost sound is formed, a means for suppressing the ghost sound should be incorporated in the processing process in advance. Thus, it is possible to efficiently suppress the generation of ghost sound.

  However, there are circumstances that cannot be avoided in selecting the gear ratio of gears and the number of cutter strips required for the transmission. Therefore, in the gear cutting step, it is inevitable to cut gears with a machining specification that satisfies either M = ± 1. It may be necessary to adopt a processing specification that suppresses ghost noise as much as possible.

  That is, when gear cutting is performed with a machining specification satisfying any of M = ± 1, there is a high probability that the tooth surface of the gear has a swell with continuous smooth regularity that affects the ghost sound. However, the undulations formed on each tooth surface are continuously continuous even between adjacent tooth surfaces, and are maintained while maintaining the periodicity of the undulations, and the entire gear has the same periodicity. When the specification is adopted, there is a high probability that a ghost sound will be generated, and there is a high probability that the ghost sound will be increased.

Therefore, in the gear cutting step, when an arbitrary natural number is N2 and the remaining integer part is K, T = N2 × H + K, and the feed pitch Vf does not satisfy T = N2 × H + 1 or T = N2 × H−1. By setting the teeth, the undulations formed on the respective tooth surfaces are smoothly arranged with few steps between the respective tooth surfaces, and the periodicity of the undulations is maintained as it is as a whole. I am doing so.

Specifically, by defining the one-tooth meshing length δ, the one-tooth meshing length δ at any i-th tooth of the gear meshes, and then 1 at the i + 1-th tooth meshing following the i-th tooth. Since the tooth meshing length δ meshes, a tool mark number T is adopted that interrupts the smooth continuity between the adjacent i-th tooth and the (i + 1) -th tooth and disturbs the periodicity of the waviness of the entire gear. Thus, it is possible to suppress or mitigate ghost sounds.
Here, the tool mark number T, when referenced to one tooth meshing length corresponding [delta], feed pitch Vf size Kusure if tool marks number T number of tools is reduced, increased if small Kusure the feed pitch Vf .

  That is, when a tool mark number T that satisfies T = N2 × H + 1 or T = N2 × H−1 is adopted, both the left-handed helical gear and the right-handed helical gear are incorporated in the state where the gear is incorporated and actually engaged. Is assumed, the number of the last tool mark of the one-tooth meshing length δ formed on the i-th tooth and the number of the first tool mark of the one-tooth meshing length δ formed on the i + 1th tooth are assumed. However, since they are sequentially arranged one by one, in either the left-handed helical gear or the right-handed helical gear, there is a combination in which the steps are smoothly smooth with few steps and the periodicity of the swell is maintained as it is. End up.

Therefore, by setting the feed pitch Vf that does not satisfy T = N2 × H + 1 or T = N2 × H−1, the undulations formed on the tooth surfaces are smoothly and continuously between adjacent tooth surfaces. Combinations in which the periodicity of the swell is maintained as it is as a whole can be avoided.

As described above, the feed pitch Vf that does not satisfy T = N2 × H + 1 or T = N2 × H−1 is set and formed on the i-th tooth, assuming both a left-handed helical gear and a right-handed helical gear. The line number of the last tool mark at the one-tooth meshing length δ and the line number of the first tool mark at the one-tooth meshing length δ formed on the i + 1th tooth are sequentially arranged one by one. In order to prevent ghosting effectively at the gear cutting stage by interrupting the smooth continuity between any adjacent i-th teeth and (i + 1) -th teeth and disturbing the periodicity of the undulation of the entire gear. Sound can be suppressed.

  Therefore, in order to eliminate the ghost sound, the invention according to claim 1 can effectively suppress the ghost sound that occurs unexpectedly at the stage of gear cutting by a simplified and simple method. Therefore, it is possible to reduce the man-hours by reducing the excessive burden caused by excessive polishing.

The invention according to claim 2 is the helical gear machining method according to claim 1, wherein the one-tooth meshing length δ is δ = πm / where m is the gear module and β is the twist angle. It is characterized by being sin β.
According to such a configuration, by defining the one-tooth meshing length δ as δ = πm / sin β, it is possible to efficiently suppress the generation of the ghost sound of the helical gear by a simplified method. .

The invention according to claim 3 is the helical gear machining method according to claim 1 or 2, wherein when the gear is a left-handed helical gear, when M = -1, T = The feed pitch Vf that does not satisfy N2 × H + 1 is set and gear cutting is performed.
According to such a configuration, by determining whether the helical gear is left-handed or right-handed and distinguishing it, it is possible to widen the applicable processing specification range while suppressing the ghost sound more reliably.

The invention according to claim 4 is the helical gear machining method according to claim 3, wherein the feed pitch Vf is set and geared so as to satisfy T = N2 × H-1. To do.
According to such a configuration, it is possible to avoid the feed speed V that satisfies T = N2 × H + 1 and set the feed speed V that can suppress the ghost sound more reliably.

The invention according to claim 5 is the helical gear machining method according to claim 1 or 2, wherein when M = + 1 in the case where the gear is a left-handed helical gear, T = N2 The feed pitch Vf that does not satisfy xH -1 is set and gear cutting is performed.
According to such a configuration, by determining whether the helical gear is left-handed or right-handed and distinguishing it, it is possible to widen the applicable processing specification range while suppressing the ghost sound more reliably.

The invention according to claim 6 is the helical gear machining method according to claim 5, wherein the feed speed V is set so as to satisfy T = N2 × H + 1 and gear cutting is performed.
According to such a configuration, it is possible to avoid the feed pitch Vf that satisfies T = N2 × H-1 and set the feed speed V that can suppress the ghost sound more reliably.

The invention according to claim 7 is the helical gear machining method according to claim 1 or 2, wherein when the gear is a right-handed helical gear, when M = -1, T = The feed pitch Vf that does not satisfy N2 × H-1 is set and gear cutting is performed.

The invention according to an eighth aspect is the helical gear machining method according to the seventh aspect, wherein the feed pitch Vf is set so as to satisfy T = N2 × H + 1 and gear cutting is performed.

The invention according to claim 9 is the helical gear machining method according to claim 1 or 2, wherein when M = + 1 in the case where the gear is a right-handed helical gear, T = N2 The feed pitch Vf that does not satisfy xH + 1 is set and gear cutting is performed.

The invention according to claim 10 is the helical gear machining method according to claim 9, wherein the feed pitch Vf is set and geared so as to satisfy T = N2 × H-1. To do.

The invention according to claim 11 is the helical gear machining method according to any one of claims 1 to 10, wherein the feed pitch Vf that does not satisfy the condition of T = N2 × H ± 1 is recognized. It is characterized by cutting gears based on the work specifications that can be made.
According to such a configuration, an operator can easily and reliably adopt an appropriate machining specification by referring to the work specification.

  The invention according to a twelfth aspect is the helical gear machining method according to the eleventh aspect, wherein the work specification clearly specifies a machining condition that is prohibited from being set in the gear cutting step. . According to such a configuration, it is possible to easily determine the machining specifications that the operator must avoid.

  A thirteenth aspect of the present invention is the helical gear machining method according to the eleventh aspect, wherein the work specifications clearly indicate machining conditions that can be set in the gear cutting step. According to this configuration, an operator can easily adopt an appropriate machining specification.

  The present invention can provide a processing method of a helical gear that determines whether or not a machining specification has a high probability of generating a ghost sound and suppresses the ghost sound by adjusting the feed rate of the cutter.

It is a perspective view which shows the mode of a general gear cutting process, (a) shows a mode that a gear is processed while sending a cutter from the bottom up, (b) shows the number of teeth of 5 cutters, a gear, Conceptually shows the relationship. It is a figure for demonstrating the state of the tool mark formed in the tooth surface at the time of processing a gear with 44 teeth with a 5-thread cutter, (a) is an arrangement order of the tool mark in each tooth surface. (B) conceptually shows the state of undulation formed on the tooth surface, and (c) is a side view schematically showing a state in which the rotation center of the cutter is deviated. It is a schematic diagram of a tooth surface for explaining a tooth contact state when an R tooth surface is accelerated when a right-handed helical gear and a left-handed helical gear mesh with each other, and (a) is a right-handed helical gear. Clockwise, (b) shows a state in which the left helical gear rotates counterclockwise. It is a schematic diagram of a tooth surface for explaining a tooth contact state when an L tooth surface is accelerated when a right-handed helical gear and a left-handed helical gear mesh with each other, and (a) shows a right-handed helical gear. Counterclockwise, (b) shows a state in which the left helical gear rotates clockwise. It is a schematic diagram for demonstrating the state of the tool mark formed in a tooth surface, (a) is a fragmentary perspective view of the tooth surface of a gearwheel, (b)-(d) is relative of the cutting amount of each line | wire of a cutter. It is a conceptual diagram which shows a difference. It is a figure for demonstrating the state of the tool mark formed in the tooth surface at the time of processing a gear with 44 teeth of a left-handed twist with a 6-thread cutter, (a) is a figure of the tool mark in each tooth surface. The arrangement order is shown, (b) conceptually shows the state of undulation formed on the tooth surface, and (c) is a side view schematically showing the state where the rotation center of the cutter is displaced. It is a figure for demonstrating the state of the tool mark formed in the tooth surface at the time of processing a gear with 44 teeth of left-handed twist with a 3 piece cutter. It is a figure for demonstrating the state of the tool mark of the other example in the case of processing a gear with the number of teeth of a left-handed twist of 44 teeth with three cutters. It is a table | surface for demonstrating the relationship between the combination of the number of teeth, the number of strips, and a ghost sound. It is a typical perspective view for demonstrating the part for 1 tooth meshing in a gearwheel. It is the figure which analyzed the relationship between the number of tool marks and a ghost order, (a) is processing a 44-tooth gear with a 5-thread cutter, (b) is processing a 49-tooth gear with a 6-tooth cutter. Show the case. It is a figure for demonstrating the relationship between the eccentricity of a cutter, and a ghost sound, (a) is sectional drawing which shows a mode that a cutter is eccentric, (b) is the extent of the eccentricity of a cutter, and a ghost sound. It is a graph which contrasts. It is a figure which shows the continuity of each tooth | gear at the time of processing a gear with 44 teeth of a left-handed twist with a 5-thread cutter, (a) is a tool mark formed in one tooth meshing length δ It is a table | surface which shows the tool mark formed in each tooth from the 1st tooth to the 4th tooth when the number is 4 to 11, and (b) is from the first tooth to the fourth tooth. It is the figure which arranged the tool mark formed in each tooth | gear continuously, (c) is a table | surface which shows the relationship between a feed pitch and the number of tool marks formed in one tooth meshing length. It is a figure which shows the continuity of each tooth | gear at the time of processing a gear with 44 teeth of right-handed twisting with 5 thread | saw cutters, (a) is a tool mark formed in one tooth meshing length δ It is a table | surface which shows the tool mark formed in each tooth from the 1st tooth to the 4th tooth when the number is 4 to 11, and (b) is from the first tooth to the fourth tooth. It is the figure which arranged the tool mark formed in each tooth continuously. It is a figure which shows the relationship between the rotation direction and the number of NG tool marks when the gear with the number of teeth of 44 in the case of the right twist and the left twist is processed with a five-thread cutter. It is a figure which shows the relationship between the feed pitch of 0.8-1.4, and a ghost sound. It is a figure which shows the relationship between the feed pitch of 1.5-2.0, and a ghost sound. It is a figure which shows the relationship between a feed pitch and the peak of a ghost sound. It is a figure for demonstrating the state of the tool mark formed in the tooth surface at the time of processing a gear with 49 teeth with a 6-thread cutter. It is a figure which shows the continuity of each tooth | gear at the time of processing a gear with 49 teeth of a left-handed twist with a 6-thread cutter. It is a figure which shows the continuity of each tooth | gear at the time of processing a gear with 49 teeth of right-handed twist with a 6-thread cutter. It is a figure which shows the relationship between the rotation direction and the number of NG tool marks when processing a gear with 49 teeth in the case of right twist and left twist with a 6-thread cutter. It is a figure which shows the process specification used as NG which has continuity in the relationship between M of Z = H * N1 + M and K of T = N2 * H + K. It is a figure which shows the example of the specification which shows the processing conditions of NG feed pitch . It is a figure which shows the example of the specification which shows the machining conditions of OK feed pitch .

  A gear machining method according to an embodiment of the present invention will be described by taking a helical gear as an example and comparing it with a machining specification having a high probability of generating a ghost sound.

  In general, when gear cutting is performed from a workpiece BL (gear blank material) with a cutter 2 such as a hob cutter or a pinion cutter, the cutter 2 is moved in the direction A shown in FIG. 1A. Then, while rotating at a high speed, it feeds in the B direction (gear width direction) illustrated from the top to the bottom and gears while rotating the workpiece BL. After completion of gear cutting, the cutter 2 is released in the C direction, moved in the D direction, and returned to the machining origin.

  And, for example, in the case of a 5-thread cutter 2, as shown in FIG. 1 (a), convex blade portions 2a arranged continuously in a spiral shape from the first thread to the fifth thread, 2b, 2c, 2d, 2e (2a to 2e) are formed. For this reason, when processing the gear 3 having the number of teeth of Z with five cutters, as shown in FIG. 1B, the tooth surfaces 3a, 3b, 3c are formed by the convex blade portions 2a to 2e. , 3d, 3e (3a to 3e) are cut, and the first tooth 3A, the second tooth 2B, the third tooth 3C, the fourth tooth 3D, the fifth tooth 3E,... Is done.

A gear processing method according to an embodiment of the present invention includes a specification determination step for determining whether or not a combination of the number of gear teeth and the number of cutter stripes is likely to cause ghost noise, and an appropriate number of teeth When gear cutting cannot be performed with the combination of the number of strips, the tool mark number calculation step is executed, and the tool mark number T of the cutter formed in the one-tooth meshing length δ becomes an appropriate number. And a gear cutting step for setting the cutter feed pitch Vf for one rotation of the gear and cutting gears .

  In the specification determining step, Z = H × N1 + M, where Z is the number of gear teeth, H is the number of cutters cutting the tooth surface of the gear, N1 is any positive integer, and M is the remaining integer portion. In this step, it is determined whether or not any of M = ± 1 is satisfied.

The specification determination step will be specifically described by taking as an example a case where a 44-tooth gear is processed with cutters (hob cutters) having 5, 6, and 3 cutters, respectively.
Here, in the case where the number of cutters is five, since 44 = 5 × 9-1 in Z = H × N1 + M, the condition of M = −1 is satisfied. Therefore, with this combination, it is assumed that there is a high probability that a ghost sound is generated.

If the number of cutters is 6, since 44 = 6 × 7 + 2 in Z = H × N1 + M, M = 2 and 44 = 6 × 8-4, so M = −4. is there.
Therefore, since none of M = ± 1 is satisfied, it is assumed that the probability that a ghost sound is generated is low in this combination.

  When the number of cutters is 3, since 44 = 3 × 15−1 in Z = H × N1 + M, the condition of M = −1 is satisfied. Therefore, with this combination, it is assumed that there is a high probability that a ghost sound is generated.

  Specifically, the specification determining step includes an arrangement order determining step for determining how the arrangement order of the tool marks formed by the first to H lines of the cutter on each tooth surface of the gear is changed. In consideration of the difference in the cutting depth by each of the strips due to the eccentricity (displacement) between the center axis and the rotation axis of the cutter in the tool marks formed by the respective strips, the tool marks are continuously Single or equi-periodic undulation (equal period undulation) having a continuous smooth (small step) regularity such that the concavo-convex shape (undulation) of the tooth surfaces formed by arranging them is close to a sine curve And a waviness shape determination step for determining whether or not to form.

  Then, in the undulation shape determination step, it can be seen that when the undulation forms a continuous smooth single wave having an approximate period close to a sine curve, or M = ± 1. In addition, when either of M = ± 1 is satisfied, it can be seen that the swell forms a continuous smooth single or equi-cycle swell close to a sine curve.

[For 5 teeth with 44 teeth]
In the specification determining step, a case where a gear having 44 teeth is cut with a cutter having 5 threads will be described with reference to FIGS. FIG. 2A to be referred to shows the arrangement order determination step, and tool marks formed on each tooth surface from the first tooth of the gear (the column of the number of teeth 1) to the 44th tooth (the column of the number of teeth 44). Are arranged in the vertical direction. In addition, the bottom row of the table is sequentially displayed such that the rotation of the work BL (see FIG. 1A) is rotated on the first round, and the top is rotated on the second turn of the work BL. FIG. 2 (b) shows the undulation shape determination step, and conceptually shows the undulation of the concavo-convex shape formed on the tooth surface in consideration of the difference in the cutting depth of each strip along the tool mark arrangement order. It is.

  The lowermost part of the table shown in FIG. 2A displays 1 as the tool mark formed on the first line of the cutter from the first tooth described in the leftmost tooth number 1 to the 44th tooth in the right direction. The tool mark formed in the second line of the cutter is displayed as 2. In the first rotation of the workpiece BL, since the first to fifth teeth of the gear are formed from the first to fifth teeth of the cutter, they are displayed as tool marks 1 to 5. Similarly, the sixth tooth to the tenth tooth of the gear are respectively formed from the first to fifth stripes of the cutter and are displayed as tool marks 1 to 5. Then, the 44th tooth is the tool mark 4 formed in the 4th line.

Thus, when the workpiece BL makes one rotation, the cutter is sent along the tooth surface in the width direction of the gear during that time (see FIG. 1A), so the first tooth following the 44th tooth is the fifth tooth. A tool mark for the line is formed. That is, the tool mark 5 is formed on the first tooth adjacent to the tool mark 1 (see the second step from the bottom of the first tooth).
As described above, in the first tooth, the gear cutting process is repeated while repeating the tool marks 1, 5, 4, 3, 2 in this order from the bottom of the table.

[Tool mark calculation step]
As shown in FIG. 10, the tool mark calculation step sets a one-tooth meshing length δ in the direction along the width direction of the gear, and calculates the number T of tool marks included in this one-tooth meshing length δ. The cutter feed pitch per rotation of the gear is Vf , and is obtained from T = δ / Vf . The one-tooth meshing length δ is a concept representing the meshing length corresponding to the main tooth contact of the gear.

The helical gear is a cylindrical gear that is a winding with helical teeth, and the helical winding with a reference cylindrical shape has a twist of β. When the gear rotates once, it advances by the lead Pz in the direction along the width direction of the gear. Therefore, the tooth meshing length δ is represented by δ = Pz / Z, where d is the reference circle diameter and m is the tooth right angle module, Pz = πd / tanβ, so δ = π × m ÷ sinβ Can be obtained.
Specifically, if m = 1.74 and the twist angle is β = 36 degrees, the length δ of one tooth meshing is δ = 3.14 × 1.74 ÷ 0.588≈9.30 mm.

Therefore, the number T of the tool marks included in the one-tooth meshing length δ is one tooth when the feed pitch of the cutter per one rotation of the gear is, for example, Vf = 1.5 (mm / gear rotation). Since the number T of tool marks included in the meshing length δ is T ′ = 9.3 ÷ 1.5 = 6.2, it is rounded off to the center portion of the tooth surface T = 6. The tool mark is extracted and considered.

Here, the tooth contact state when the helical gear is driven will be described with reference to FIGS. 3 and 4. 3 and 4 are diagrams for explaining the twisting direction, the rotational direction, and the tooth contact direction depending on the difference between the driven gear and the driving gear in the helical gear. FIG. 3 is a left-handed twist, and FIG. 4 is a right-handed twist. Indicates.
3 and 4, the Top side indicates a side to which a driving device such as an engine is connected, the Bottom side indicates a side to which a driven device such as a transmission is connected, and the rotation direction is clockwise or counterclockwise as viewed from the Top side. Indicates clockwise. Further, the root part is indicated as Root, and the tooth tip part is indicated as Tip.

  For example, as shown in FIG. 3, when a right-handed helical gear is driven to rotate clockwise as viewed from the Top side (see FIG. 3A), the counterclockwise helical gear to be paired is counterclockwise. Following rotation (see FIG. 3B). In this case, the R tooth surface is the tooth contact surface for both gears, and the right-handed helical gear, as shown in FIG. 3A, is from the bottom tooth root Root to the top tooth tip Tip. Progresses diagonally on teeth. As shown in FIG. 3 (b), the pair of left-handed helical gears advances in a diagonal manner from the bottom-side tooth tip Tip to the top-side tooth root Root in a diagonal line.

  By the way, for example, when the above gear set is incorporated in a mission assuming a car engine, a mission, and driving wheels, the rotation does not reverse. That is, when the engine speed is increased, the right-twisted helical gear is used as a drive gear, and the left-twisted helical gear is used as a driven gear. When the vehicle decelerates, the engine speed decreases, but the driving wheel rotates, so this time the left-handed helical gear is used as the driving gear, and the right-handed helical gear is used as the driven gear. Meshes and rotates.

That is, even if the functions of the drive gear and the driven gear are changed by both gears in the above process, the rotation direction is not changed.
Therefore, as shown in FIG. 3, when the left-twisted helical gear rotates counterclockwise (see FIG. 3B), the paired right-twisted helical gear rotates clockwise (see FIG. 3). 3 (a)), the L tooth surface of both gears becomes the tooth contact surface, and the helical gear of the left-handed twist is shown in FIG. 3 (b) from the root side root portion Root to the Top side tooth tip portion. The tooth progresses diagonally to Tip. As shown in FIG. 3A, the pair of right-handed helical gears advances in a diagonal manner from the bottom-side tooth tip Tip to the top-side tooth root Root in a diagonal line.

On the other hand, the example of FIG. 4 in which the rotation is in the opposite direction to the example of FIG. 3 will be described.
When the right-handed helical gear is rotated counterclockwise as viewed from the Top side (see FIG. 4A), the pair of left-handed helical gears is rotated in a clockwise direction (FIG. 4B). )reference). In this case, the L tooth surface of both gears becomes the tooth contact surface, and the helical gear with right-handed twisting, as shown in FIG. 4 (a), from the top root portion Root to the bottom tooth tip portion Tip. Progresses diagonally on teeth. The pair of left-handed helical gears advances in a diagonal manner from the top-side tooth tip Tip to the bottom-side tooth root Root in a diagonal line.

  When the left-handed helical gear rotates clockwise, the paired right-handed helical gears rotate counterclockwise, and both gears have the R-tooth surface as the tooth-contact surface, and the left-handed helical gear. The gear advances diagonally from the top side root portion Root to the bottom side tip portion Tip on a diagonal line. As shown in FIG. 4B, the pair of right helical gears advances in a diagonal manner from the top-side tooth tip Tip to the bottom-side tooth root Root in a diagonal line.

  When a normal vehicle is assumed, the structure is not a structure in which the rotation is reversed, but in general, there is a structure in which the rotation is reversed. For example, in a motor-driven gear box, the direction of rotation can be freely controlled. However, as is clear from a comparison between FIG. 3B and FIG. 4B, when the rotation is reversed, the meshing order of the teeth and the meshing direction on each tooth surface are reversed, and similar results are obtained. Become. Therefore, the present invention does not need to limit the direction of rotation, and does not exclude a structure capable of reverse rotation.

Hereinafter, the continuity of the tool mark formed on the tooth surface when a 44-tooth helical gear having a left-handed twist is machined with a 5-cutter will be described in detail.
When the left-twisted helical gear is rotated counterclockwise as a driven gear, the tooth contact advances in the direction of arrow F as shown in FIG. 5A (see FIG. 3B). Therefore, focusing on the six tool marks included in the tooth meshing length δ, the range is surrounded by a thick frame. In the first tooth, the tool mark is downward from the paper surface along the tooth width direction. 1, 2, 3, 4, 5, and 1 (see FIG. 5A).

  Similarly, in the second tooth, as shown in FIG. 5 (a), the tool mark of the first tooth is processed by the next item number, so the arrangement order is the same as that of the first tooth. Marks 1, 2, 3, 4, 5, 1 and 6 tool marks in the same range as the first tooth, when viewed from the top down, tool marks 2, 3, 4, 5, 1, 2 line up. On the third tooth, the tool marks 3, 4, 5, 1, 2, 3 are arranged.

Here, in FIG. 5A, since the streak number is not unique and the connection of the streak number is important, for convenience of explanation, the first tooth contact portion within the one-tooth meshing length δ in the first tooth The range in which the article number is 1 is extracted and considered.
Further, the actual tooth contact proceeds in the direction of arrow F, but the arrangement order of the tool marks is the same even if considered along the tooth width direction. Considering the tool marks in line.

  In the present embodiment, the meshing length corresponding to the main tooth contact of the gear is defined as δ = π × m ÷ sinβ, where δ = π × m ÷ sinβ. However, the present invention is not limited to this. It can be appropriately determined depending on the shape and size of the gear.

On the other hand, eccentricity of the central axis as an individual difference and deviation of the central axis at the time of attachment to a gear cutting machine inevitably occur within the allowable limit of machining accuracy (see FIG. 11A).
For this reason, in actual gear cutting, assuming that the rotation center C1 of the cutter is displaced toward the first tooth portion 2a (see FIG. 1) with respect to the center axis C2 of the cutter, FIG. As shown in b) to (d), the amount of cutting is deeper in the second line than in the first line (processing by the teeth of the first line), and the third and fourth lines are further deepened, The fifth item is the same depth of cut as the second item.

  When the relative difference of the cutting depth for each cutter stripe number is displayed on the graph, as shown in FIG. 2B, the tool marks 1, 2, 3, 4, 5, 1 are present on the first tooth. (FIG. 2 (a)), the difference in cutting amount between the tool mark 1 and the tool mark 2 and the difference in cutting amount between the tool mark 2 and the tool mark 3 are equal and the steps are small, so that it has continuous smoothness. Yes. And since the cutting amount of the tool mark 3 and the tool mark 4 is the same, it has smooth continuity. Furthermore, since the difference in cutting amount between the tool mark 4 and the tool mark 5 is the same and the step is small, it has continuous smoothness, and since the difference in cutting amount between the tool mark 5 and the tool mark 1 is equal, smooth continuity is also achieved. Have.

  For this reason, in the arrangement order of the tool marks 1, 2, 3, 4, 5, 1 on the first tooth, the tool marks are continuously arranged with few steps, and this change is repeated at the same cycle. A single or equi-periodic undulation (equal-period undulation) having continuous smooth regularity is formed on the tooth surface.

  Similarly, since the second tooth and the third tooth have the same arrangement order of the first tooth and the tool mark, the same period swell is formed in the same manner, and the fourth tooth to the 44th tooth are the same. An equal period swell is formed. In this way, since the arrangement order of the tool marks is the same from the first tooth to the 44th tooth, a similar equal period swell having the same regularity is formed.

  It is assumed that the equi-periodic swell having regularity common to all the tooth surfaces (from the first tooth to the 44th tooth) has a high probability of affecting the ghost sound. And it turns out that such an equal period waviness is formed when either M = ± 1 is satisfied.

[In case of 6 teeth with 44 teeth]
A case where a gear having 44 teeth is cut with a cutter having 6 threads will be described mainly with reference to FIG. The bottom row in the table of FIG. 6 is displayed as tool marks 1 to 6 because the first to sixth teeth of the gear are formed from the first to sixth teeth of the cutter, respectively. The 44th tooth is the tool mark 2 formed in the second line.

  In this way, when the workpiece BL (gear blank material) makes one rotation, the cutter is sent along the tooth surface in the width direction of the gear during that time (see FIG. 1A), so the first following the 44th tooth. The tooth has a third tool mark 3 (see the second step from the bottom of the first tooth).

  Therefore, with the first tooth, the gear cutting is repeated while repeating the tool marks 1, 3, 5, 1, 3, and 5 in this order from the bottom of the table (see FIG. 6A). On the other hand, on the second tooth, tool marks are formed so as to repeat in order of tool marks 2, 4, 6, 2, 4, 6 from the bottom of the table, and on the third tooth, tool marks 3, 5, 1, 3 , 5 and 1 are repeated. As described above, the arrangement order of the odd-numbered first teeth and the third teeth is the same, but the arrangement order of the odd-numbered first teeth and the even-numbered second teeth is different.

  Here, paying attention to the six tool marks included in the one tooth meshing length δ, the first teeth are aligned with the tool marks 1, 5, 3, 1, 5, 3 from top to bottom ( (See FIG. 6 (a)). On the other hand, the second teeth are aligned with tool marks 2, 6, 4, 2, 6, 4, and the third teeth are aligned with tool marks 3, 1, 5, 3, 1, 5.

  Then, in consideration of the relative difference in the cutting amount for each cutter strip number, as understood from FIG. 6 (c), the second and sixth items rather than the first item are compared to the first item. The amount of cut is deeper in the line, the third and fifth are deeper, and the fourth is the deepest cut.

When the relative difference of the cut amount for each cutter stripe number is displayed on the graph, as shown in FIG. 6B, the first teeth are in the order of tool marks 1, 5, 3, 1, 5, 3. (FIG. 4 (a)), since the difference in cutting amount between the tool mark 1 and the tool marks 5 and 3 is relatively large, the level difference is large and the continuous smoothness is lacking.
Similarly, since the second teeth are in the order of 2, 6, 4, 2, 6, 4 (FIG. 6A), the difference in the cutting amount between the tool marks 2 and 6 and the tool mark 4 is large. The steps are relatively large and lack continuous smoothness.

  Moreover, the uneven undulations formed on the odd-numbered first teeth are uneven and formed on the even-numbered second teeth, whereas the tool marks 1 are shallow and the tool marks 5 and 3 are deep. Swelling is deeper than tool mark 1 in tool marks 2 and 6, and the tool mark 4 is deeper than tool marks 2 and 6, so the uneven shape and depth are different. I don't have it. Therefore, it is considered that the probability that a ghost sound is generated is low because an equal period swell having regularity (equal period) common to all tooth surfaces does not occur.

[For 3 teeth with 44 teeth (6 tool marks)]
A case where a gear having 44 teeth is cut with a cutter having 3 threads will be described mainly with reference to FIG.
The bottom row in the table of FIG. 7 is displayed as tool marks 1 to 3 because the first to third teeth of the gear are formed by the first to third teeth of the cutter, respectively. The 44th tooth is the tool mark 2 formed in the second line.
In this way, when the work BL rotates once, the cutter is sent along the tooth surface in the width direction of the gear during the rotation (see FIG. 1A), so the first tooth following the 44th tooth is the third tooth. The tool mark 3 of the line is formed (see the second step from the bottom of the first tooth).

  Therefore, with the first tooth, the gear cutting process is repeated while repeating the tool marks 1, 3, 2, 1, 3, 2 from the bottom of the table (see FIG. 7A). On the other hand, the arrangement order of the second teeth is the same as that of the first teeth, but starts with the tool mark 2 shifted from the first tooth by one, and the tool marks 2, 1, 3, 2, 1, Tool marks are formed so as to be repeated in the order of 3, and the third tooth starts with the tool mark 3 further shifted by one and repeats in the order of the tool marks 3, 2, 1, 3, 2, 1.

  As described above, although there is a deviation, the arrangement order of the tool marks is the same for all teeth except for the difference between the start end and the end, so that it has regularity (equal periodicity) common to all tooth surfaces, etc. Periodic undulation occurs.

Focusing on the six tool marks included in one tooth meshing length δ, the first teeth are aligned with tool marks 1, 2, 3, 1, 2, 3 from top to bottom (FIG. 5 ( a)). The second tooth is aligned with tool marks 2, 3, 1, 2, 3, 1 and the third tooth is aligned with tool marks 3, 1, 2, 3, 1, 2.
Then, in consideration of the relative difference in the cutting amount for each cutter strip number, as understood from FIG. 7 (c), the second and third items rather than the first item are compared with the first item. The amount of cut is deeper in the line.

  When the relative difference of the cutting amount for each cutter stripe number is displayed on the graph, as shown in FIG. 7B, in the first tooth, the difference between the cutting amounts of the tool mark 1 and the tool marks 2 and 3 is large. Although lacking in continuity, it has equi-periodicity. Similarly, in the second tooth and the third tooth, the difference in cutting amount between the tool marks 2 and 3 and the tool mark 1 is large and lacks continuous smoothness. Since the arrangement order of the marks is the same, it has the same regularity (equal periodicity) common to each tooth.

  Therefore, it is not appropriate to determine that the probability of occurrence of ghost noise is low. Avoid such processing specifications and change to processing specifications with low probability of ghost noise generation, or management of cutter eccentricity, etc. It is desirable to take measures in advance, such as stricter accuracy control and increasing the machining allowance for finishing.

[For 3 teeth with 44 teeth (7 tool marks)]
Here, when the cutter feed pitch Vf is slowed (decreased) and adjusted so that the number of tool marks included in the one-tooth meshing length δ is 7, the relative difference in cutting amount for each cutter strip number As shown in FIG. 8B, the graph of FIG. 8 is arranged with tool marks 1, 2, 3, 1, 2, 3, 1 on the first tooth (see FIG. 6A). The second tooth is aligned with tool marks 2, 3, 1, 2, 3, 1, 2, and the third tooth is aligned with tool marks 3, 1, 2, 3, 1, 2, 3.

  When the swell of the 6 tool marks displayed in FIG. 7B and the swell of the 7 tool marks displayed in FIG. 8B are compared, the swell of the 7 tool marks is greater than the swell of the 6 tool marks. Since the regularity (regularity) on the tooth surface is improved, the regularity common to each tooth surface is increased, and therefore, the probability that a ghost sound is generated is assumed to be higher.

As described above, the length of the tool mark in the feed direction is changed by adjusting the feed pitch Vf of the cutter, so that the period of the equal period swell formed on each tooth surface is changed, the adjacent tooth surface is Since the continuity of the periodic undulation changes, it is assumed that the magnitude of the ghost sound and the probability of occurrence of the ghost sound are different. This point will be described in detail in the gear cutting step described later.

Note that the number of teeth Z ÷ the number H is divisible, as in the case where a gear having 44 teeth is cut with a cutter having two or four lines, and M = 0 when Z = H × N1 + M There is a case.
In the case of such a combination, the tool mark 1 by the first line is formed on the tooth surface of the first tooth, and the tool mark 1 by the second line is formed on the tooth surface of the second tooth. In this way, the unique characteristics of the cutter stripe number are all reflected on the specific tooth surface. For this reason, since it is a combination that is usually not adopted, the above-described equal period swell does not occur, but a detailed description of such a combination is omitted.

  Based on the above results, the relationship between the number of teeth of the gear and the number of strips of the cutter is summarized as shown in FIG. FIG. 9 shows the relationship between the number of teeth and the number of teeth when gears having a number of teeth of 10 to 49 are cut with a cutter having a number of teeth of 2 to 6, and in Z = H × N1 + M, M = ± 1 is described.

  “O” in the table is a combination that does not satisfy M = ± 1 and is unlikely to generate a ghost sound, and “indication of 1 and −1” in the table indicates that M = ± 1. It is a combination that satisfies any one and is assumed to have a high probability of generating a ghost sound, and the “display of 0” in the table is a combination that is desirably avoided because it is a combination in which M = 0.

  Next, the generation pattern of the ghost sound in the case where the 44-tooth left helical gear is cut with a 5-cutter will be mathematically examined. As shown in FIG. 11, an integer is taken as the number of tool marks, and the number of teeth 44 is made to correspond to a place corresponding to 5 of 5 cutters. 44 ÷ 5 = 8.8 is placed next to the number of tool marks 1 to correspond, and a multiple of 8.8 is sequentially placed for each integral multiple of the number of tool marks. In this way, 35.2 corresponds to the number 4 of tool marks, and 52.8 corresponds to the number 6 of tool marks.

  In consideration of the fact that 44-tooth gear noise is generated in the 44th order and its integral multiple, this fact is 35.2nd when the number of tool marks is 4, 35th order in the integer expression, and the number of tool marks is 6th. That is, it is suggested that a 52.8th order ghost sound is generated in the case of 6 tool marks and a 53rd order ghost sound is generated in the integer expression.

  Furthermore, if a ghost sound is generated with an integer multiple of the number of cutter stripes, for example, a pattern with the number of cutter stripes minus 1, the order of the ghost sound is 35th order (35.2), 79th order (79.2), 123 Next (123.2), if a ghost sound is generated in the pattern of the number of cutter stripes + 1, the order of the ghost sound is 53th order (52.8), 97th order (96.8), 141st order (140.140). 8).

Next, the gear cutting step will be described mainly with reference to FIGS.
FIG. 13A shows a tool mark formed in the length δ of one tooth meshing by adjusting the feed pitch of the cutter when gears with 44 teeth are cut with five cutters. It is a table | surface which shows the arrangement | sequence order of the tool mark formed in each tooth from the 1st tooth to the 4th tooth when the number T is 4 to 11. FIG.13 (b) is the figure which arranged the tool mark formed in each tooth from a 1st tooth to a 4th tooth continuously. FIG. 13C is a table showing the relationship between the feed pitch and the number of tool marks formed in the one-tooth meshing length δ.

The gear cutting step sets a feed pitch Vf that does not satisfy T = N2 × H + 1 or T = N2 × H-1, where T = N2 × H + K, where N2 is an arbitrary natural number and K is the remaining integer part. And cut into teeth.
Further, in the case of the left helical gear as in this embodiment, when M = −1, the feed pitch Vf that does not satisfy T = N2 × H + 1 is set and geared .

Specifically, when gears with 44 teeth are cut with 5 cutters, since Z = H × N1 + M, 44 = 5 × 9-1, M = −1. A feed pitch Vf that does not satisfy N2 × H + 1 (K = 1) is set. This is because, as shown in FIG. 13A, when the number of tool marks T = 6, 11, T = 1 × 5 + 1 and T = 2 × 5 + 1 are satisfied, so that K = 1 and smooth between the teeth. The continuity with few steps is generated and the periodicity of the equal period swell formed on each tooth surface is maintained as it is as a whole. Is maintained as it is.

[When 44-tooth left helical gear is driven gear]
For example, in the case of 6 tool marks, as shown in FIG. 13 (a), it is assumed that a left-twisted helical gear is used as a counterclockwise driven gear (see FIG. 3 (b)). Since the order of the tool marks is viewed from the top to the bottom of the table, the first teeth are arranged in the order of tool marks 1, 2, 3, 4, 5, 1, and the second tooth has tool marks 2, 3, 4, 5, 1, 2 in order, tool marks 3, 4, 5, 1, 2, 3 in order on the third tooth, tool marks 4, 5, in the fourth tooth Lined up in the order 1, 2, 3, 4.

  Then, when these tool marks are continuously arranged from the first tooth to the fourth tooth, a smooth level difference from the first tooth to the fourth tooth is displayed as shown in FIG. Less continuity is generated, and the periodicity of the equal period swell formed on each tooth surface is maintained as it is as a whole, and is connected from the first tooth to the fourth tooth, and continues to the 44th tooth.

  That is, the continuity between the first tooth and the second tooth is determined by the first tool of the first tooth mesh length δ of the second tooth following the last tool mark 1 of the first gear mesh length δ of the first tooth. Since the mark 2 is continuous, the tool marks 2, 3, 4, 5, 1 and 2 of the second tooth are continuous after the tool marks 1, 2, 3, 4, 5 and 1 of the first tooth. The first tooth is connected to the second tooth in a state in which the periodicity of the equal period waviness is maintained as it is. The continuity between the second tooth and the third tooth is the same, and the periodicity of the equal period undulation is continuously maintained up to the 44th tooth.

  For this reason, in the case of 6 tool marks, it is assumed that there is a higher probability that a ghost sound will be generated and that the ghost sound will be louder than the other cases described below. For this reason, it is desirable to exclude such processing specifications. The same applies to the case of 11 tool marks, and the description is omitted.

  On the other hand, in the case of 4 tool marks, for example, tool marks 1 and 4 are connected between the first tooth and the second tooth so as to display “no continuity” in FIG. Since the line numbers are separated, a larger step is produced than in the case of 6 tool marks connected by adjacent line numbers. In the case of 5 tool marks, for example, the tool marks 1 and 3 are connected between the first tooth and the second tooth, so that a larger step is similarly generated than in the case of 6 tool marks.

  On the other hand, in the case of 7 tool marks, for example, tool mark 1, 1, 2, and 2 do not have a step difference, so that the periodicity of the equal period undulation formed on the first tooth is present. Instead of being maintained as it is, the periodicity is disturbed and weakened in a portion where no step is generated.

In the case of 8 tool marks, the tool marks 5 and 1 are repeated again after the tool marks 5 and 1 in the continuity of the first tooth and the second tooth, so that the periodicity is disturbed.
In the case of 9 tool marks and 10 tool marks, a larger step is generated than in the case of 6 tool marks as in the case of 5 tool marks.

[When 44-tooth left helix gear is drive gear]
In the other pattern of FIG. 3, when the left helix gear is driving rotation and the right helix gear is driven rotation, the rotation and tooth contact of both gears are the opposite, so that 44 left helix gears are 5 When the teeth are cut by the strip cutter, the equal period waviness is continuous between the teeth at the 6 and 11 tool marks.
Therefore, when the left helical gear shown in FIG. 3 (b) is counterclockwise, driving rotation or driven rotation, and having 6 tool marks and 11 tool marks, the equal period waviness is continuous between the teeth. .
That is, when the left helical gear rotates counterclockwise and M = −1 due to the number of machining cutters, if T = N2 × H + 1 is satisfied, the equal period waviness will be continuous between the teeth.

[When 44-tooth right helix gear is the drive gear]
Here, a tool mark for cutting a 44-tooth right-handed gear (see FIG. 3A), which forms a pair of left-handed gears (see FIG. 3B) as in this embodiment, with a 5-thread cutter. Consider the continuity of.
In the right helical gear of FIG. 3A, the tooth contact progresses diagonally from the bottom tooth tip Tip to the top tooth root Root by clockwise rotation.

Accordingly, in FIG. 14A, the tooth contact progresses from the right to the left of the table, and on each tooth surface, the tooth contact progresses from the top to the bottom of the table. Read tool marks from top to bottom. Specifically, 1, 2, 3, 4 from the top right to the bottom of the table, and the adjacent columns are in the same order, 5, 1, 2, 3. In this case, as shown in FIG. 14 (b), the teeth are connected from one tooth to four teeth in a state where the periodicity of the equal period waviness is maintained as a whole. Similarly, when developing up to 11 tool marks in succession, when there are 4 tool marks and 9 tool marks, the equal period undulation is continuous between each tooth.
In addition, as in the paragraph 0100 in which the left helical gear is examined, this relationship does not change even if the drive follower is changed.
Therefore, when M = −1 according to the number of machining cutters when the right helical gear is rotated clockwise, if T = N2 × H−1 is satisfied, the equal period undulation will be continuous between the teeth.

[When 44-tooth left helical gear rotates in a driven clock]
Here, in the case where the helical gear with the right twist is rotated counterclockwise when viewed from the Top side in FIG. 4 (see FIG. 4A), the counterclockwise counterclockwise rotating helical gear (see FIG. The inter-tooth continuity of the equal period swell in b) is examined.
When gearing a 44-tooth left helical gear with a 5-thread cutter, refer to FIGS. 14 (a) and 14 (b), and although not specifically shown, the rotation is clockwise, so the tooth contact is the table. Since the process proceeds from right to left and from bottom to top (see FIG. 4B), the tool mark is read accordingly. For example, in the case of 6 tool marks, when reading from the lower right of the table to the top, it is aligned with 4, 3, 2, 1, 5, 4 and when moving to the left of the table and reading from the bottom to the top, 3, 2, 1, 5 4,3, and 2,1,5,4,3,2 and 1,5,4,3,2,1 as well, so that the equal period waviness is continuous between each tooth. . The same applies to 11 tool marks.

  Furthermore, since the left helix gear rotates in the clockwise direction and the direction of contact with the tooth surface, and the contact with the tooth surface advances from the bottom to the top by clockwise rotation, refer to FIGS. 14 (a) and 14 (b). Similarly, although not specifically shown, the equal period waviness between the 6 tool marks and the 11 tool marks is continuous between the teeth.

[When 44-tooth right helix gear rotates counterclockwise]
In the case of rotating the clockwise helical gear counterclockwise as viewed from the Top side, which is another pattern of FIG. 4, the inter-tooth undulation between the right-handed helical gears (FIG. 4A). Consider continuity.
When cutting a 44-tooth right helical gear with a 5-cutter, refer to FIGS. 14 (a) and 14 (b). Although not specifically shown, the rotation is counterclockwise and the tooth contact is from bottom to top. Since the tooth contact progresses from left to right in the table from bottom to top, the tool mark is read accordingly. For example, with 4 tool marks, 1, 5, 4, 3 and 2, 1, 5, 4 and 3, 2, 1, 5 and 4, 3, 2, 1, and so on There will be continuity. The same applies to the 9 tool marks.

  Further, even when the counterclockwise rotation of the right helix gear, the rotation direction and the tooth contact direction are counterclockwise and the contact of the tooth surface advances from the bottom to the top (see FIG. 4A). With reference to a) and (b), although not specifically shown, similarly, the equal period waviness between the 4 tool marks and the 9 tool marks is continuous between the teeth.

  Here, when gears with 44 teeth are cut with a cutter with 5 threads, since M2 = -1, it is set when the cutter runout is actually 10μ and 120μ. In this way, it is determined whether or not a ghost sound is generated.

  As a result of collecting the vibration measurement data of the gears by the bench test and analyzing the order of whether or not a ghost sound is generated, as shown in FIG. The peak was observed. Therefore, it can be seen that a ghost sound derived from the 53rd-order amplitude is generated. Since the amplitude peak is clearer at 120 μ than at 10 μ, it is assumed that the ghost sound also increases.

  The result shown in FIG. 11 with mathematical examination and the experimental result shown in FIG. 12 are in good agreement, and it was proved that a ghost sound is generated by the combination of the number of gear teeth and the number of cutter strips. What should be clarified next is the relationship between the tooth surface shape and the ghost sound by the combination of the number of gear teeth and the number of cutter strips.

  FIG. 15 shows a summary of the above examination results, and it is the specification of the gear that influences the inter-tooth continuity of the equal period waviness, which is right-handed or left-handed. It does not matter whether the gear rotates or whether it is driven or driven.

Next, the relationship between the feed speed and the ghost sound when the feed speed is appropriately adjusted and geared will be described with reference to FIGS. 16 and 17. FIGS. 16 and 17 are diagrams showing the result of order analysis of the tooth surface shape of a gear having 44 teeth cut by a cutter having 5 threads, and FIG. 16 shows a feed pitch from 0.8. 1.4 [mm / rotation of the gear] to, in FIG. 17 sends ghost sounds when the pitch has gear cutting is divided into eight stages between from 1.5 to 2.0 [rotation mm / gear] Indicates the state. In addition, since it is a separate gear with different feed speeds at each stage, the lateral comparison between the respective feed speeds is not accurate.

Amplitude peaks derived from ghost sounds occur in the 53rd, 97th, and 141st orders.
For example, as shown in FIG. 16A, when the feed pitch is 0.8 [mm / gear rotation] , the 97th order peak is more prominent than the other 53rd and 141st orders. It is assumed that there is a high probability that the next ghost sound will occur. Therefore, the feed pitch becomes 11 tool mark satisfying K = + 1, it is desirable that the processing specification of 0.8 [rotation mm / gear] to eliminate (see FIG. 13 (c)).

When the feed pitch is 1.0 [mm / gear rotation] , it becomes a 9.3 tool mark (FIG. 13 (c)), but the 97th order peak decreases as shown in FIG. 16 (b). And the 53rd order peak is rising. When the feed pitch is 1.2 [mm / gear rotation] , the tool mark is 7.75, but the 97th order peak is further lowered and the 53rd order peak is increased. Thus, it can be seen that the 53rd-order peak and the 97th-order peak are in a relationship in which the 97th-order peak decreases as the 53th-order peak increases (see FIG. 17).

On the other hand, the 53 peaks, because the feed pitch is 1.2 [mm / rotation of the gear] significantly increased beginning, the feed pitch is beginning to descend from 1.8 Rotate the mm / gears, feed pitch Is found to reach a peak in the range of 1.4 to 1.6 [mm / gear rotation] , and the feed pitch is in the vicinity of 1.5 [mm / gear rotation]. Can be acknowledged.

Therefore, as shown in FIG. 18, the 53rd order peak is around the feed pitch of 1.5 [mm / gear rotation] , and the 97th order peak is the feed pitch of about 0.8 [mm / a rotation around the gear 53 following the peak and 97-order ghost sound to both amplitude falling in the middle near the peaks are assumed to be reduced. When the feed pitch is 1.5 [mm / gear rotation] , it is 6.24 tool mark, and when the feed pitch is 0.8 [mm / gear rotation] , it is 11.69 tool mark. It can be seen that the 6 tool marks satisfying the above and 11 tool marks substantially match.

  Furthermore, as another example, the continuity of the tool marks from the first tooth to the 49th tooth when a helical gear having 49 teeth is twisted with six cutters is shown in FIGS. , And with reference to FIGS. 19 and 20.

[In case of 6 teeth cutter with 49 teeth of left twist]
For example, when the right-handed helical gear is driven to rotate clockwise as viewed from the Top side, the paired left-handed helical gear rotates counterclockwise (see FIG. 3B). In this case, in both gears, the R tooth surface becomes the tooth contact surface, and the right-handed helical gear advances in a diagonal manner from the bottom side root portion Root to the top side tooth tip portion Tip. The pair of helical gears of left-handed torsion advances diagonally from the bottom tooth tip Tip to the top tooth root Root on a diagonal line.

Therefore, from FIGS. 20 (a) and 20 (b), since the helical gear of left-handed rotation rotates counterclockwise and the tooth contact advances from top to bottom, the tooth contact advances from top to bottom from left to right. Read the tool mark accordingly. For example, with 5 tool marks, 5, 4, 3, 2, 1, and 6, 5, 4, 3, 2, and 1, 6, 5, 4, 3, and 2, 1, 6, 5, 4, Thus, the equal period swell is continuous between each tooth. That is, the figure of 5 tool marks in FIG. 19B is read from above. The same applies to 11 tool marks.
Further, in the same direction of left twist, that is, counterclockwise rotation, even between driven and driven, equal waviness between teeth is generated at 5, 11 tool marks as described above. This is because the rotation direction and the tooth surface contact direction coincide with each other, as in the case where a 44-tooth gear is cut with a five-cutter.

  In the case of extracting a predetermined tool mark from the one tooth meshing length δ, the line number is not unique and the connection of the line numbers is important. The range was selected so that the lowest row number in the minute length δ was 1.

  On the other hand, when the rotation is reversed, that is, when the right-handed helical gear is driven to rotate counterclockwise when viewed from the Top side, the counterclockwise helical gear that is paired rotates in a clockwise manner (FIG. 4). (See (b)). In this case, the L tooth surface becomes the tooth contact surface in both gears, and the right-handed helical gear advances in a diagonal manner from the top side root portion Root to the bottom side tooth tip portion Tip. The pair of left-handed helical gears advances in a diagonal manner from the top-side tooth tip Tip to the bottom-side tooth root Root in a diagonal line.

Therefore, from FIGS. 20 (a) and 20 (b), since the helical gear of the left-handed rotation rotates clockwise and the contact of the tooth surface advances from the bottom to the top, the tooth contact advances from the bottom to the right to the left. Read the tool mark accordingly. For example, with 5 tool marks, 4, 5, 6, 1, 2, and 3, 4, 5, 6, 1, and 2, 3, 4, 5, 6, and 1, 2, 3, 4, 5, Thus, the equal period swell is continuous between each tooth. The figure of 5 tool marks in FIG. 20B is read from below. The same applies to 11 tool marks.
Further, in the same direction of left-handed twist, that is, clockwise rotation, the inter-tooth equal period waviness occurs at the 5 and 11 tool marks in the same manner as described above, whether driven or driven. This is because the rotation direction and the tooth surface contact direction coincide with each other, as in the case where a 44-tooth gear is cut with a five-cutter.

[In the case of 6-cutter with 49 teeth with right twist]
When the right-handed helical gear is driven to rotate clockwise as viewed from the Top side, the R tooth surface becomes the tooth contact surface, and the right-handed helical gear moves from the root side root portion Root to the top side tooth tip portion. The tooth progresses diagonally to Tip.

Accordingly, from FIGS. 21 (a) and 21 (b), the right helix gear rotates clockwise and the tooth contact advances from the top to the bottom, so the tooth contact advances from the right to the left to the top. Read the tool mark. For example, for 7 tool marks, 4, 3, 2, 1, 6, 5, 4, and 3, 2, 1, 6, 5, 4, 3, and 2, 1, 6, 5, 4, 3, 2 Then, 1, 6, 5, 4, 3, 2, 1, and the equal period waviness is continuous between the teeth. The figure of 7 tool marks in FIG. 21B is read from above. The same applies to the 13 tool marks.
Further, in the same direction of right twist, that is, clockwise rotation, even between driven and driven, equal waviness between teeth is generated at 7 and 13 tool marks as described above. This is because the rotation direction and the tooth surface contact direction coincide with each other, as in the case where a 44-tooth gear is cut with a five-cutter.

On the other hand, when the rotation is opposite to that of paragraph 0122, that is, when the helical gear with the right twist is driven to rotate counterclockwise as viewed from the Top side, the L tooth surface becomes the contact surface and the helical gear with the right twist is From the top side root portion Root to the bottom side tip portion Tip, the tooth contact progresses diagonally.
Accordingly, from FIGS. 21 (a) and 21 (b), since the right helix gear rotates clockwise and the tooth contact advances from the bottom to the top, the tooth contact advances from the bottom to the left to the right. Read the tool mark. For example, with 5 tool marks, 1, 2, 3, 4, 5, 6, 1 and 2,3,4,5,6,1,2 and 3,4,5,6,1,2,3 Then, 4, 5, 6, 1, 2, 3, and 4, and the equal period waviness is continuous between the teeth. The figure of 7 tool marks in FIG. 21B is read from below. The same applies to the 13 tool marks.
Also, in the same direction of right twist, that is, counterclockwise rotation, even between driven and driven, equal waviness between teeth is generated at 7 and 13 tool marks as described above. This is because the rotation direction and the tooth surface contact direction coincide with each other, as in the case where a 44-tooth gear is cut with a five-cutter.

  FIG. 22 summarizes the above examination results, and it is the specification of the gear that influences the inter-tooth continuity of the equal period waviness, which is right-handed or left-handed. It does not matter whether the gear rotates or whether it is driven or driven.

Here, it is examined whether a common principle independent of the number of gear teeth and the number of cutter strips can be established. As already discussed in paragraph 0110, it does not matter whether the gear rotates or whether it is driven or driven (see FIGS. 3 and 4).
For example, although illustration is omitted, when a 27-tooth gear with left-handed twist is machined with a four-cutter, M in the equation Z = H × N + M is −1, and the continuity of the inter-tooth equal period waviness is 5, 9 tools When marking, the number of tool marks is +1 with respect to an integral multiple of the number of cutters.
Next, although illustration is omitted, when a left-handed twisted 35-tooth gear is machined with a six-cutter, M in the formula Z = H × N + M is −1, and the continuity of the inter-tooth equal period swell is 7,13. At the time of tool mark, the number of tool marks is +1 with respect to an integral multiple of the number of cutters.
Next, when machining the left-handed 44-tooth gear with a 5-thread cutter, M in the formula Z = H × N + M is −1, and the continuity of the inter-tooth equal period waviness is 6 and 11 tool marks. And is +1 for an integer multiple of the number of cutters.
From the above three cases, when machining a left helical gear with a cutter, the continuity of periodic waviness between teeth is an integral multiple of the number of cutters when M = -1 in the formula Z = H × N + M. When the number of tool marks is +1.

Next, although not shown in the drawing, when a left-handed 21-tooth gear is machined with a four-thread cutter, M in the formula Z = H × N + M is +1, and the continuity of the inter-tooth equal-period waviness is 3, 7 tools. At the time of marking, the number of tool marks is -1 with respect to an integral multiple of the number of cutters.
Next, although not shown in the drawing, when processing a left-handed twisted 35-tooth gear with a 6-thread cutter, M in the equation Z = H × N + M is +1, and the continuity of the inter-tooth equal period undulation is 4,9 tools. At the time of marking, the number of tool marks is -1 with respect to an integral multiple of the number of cutters.
Next, although illustration is omitted, when a 43-tooth gear with a left-hand twist is machined with a 6-cutter, M in the formula Z = H × N + M is +1, and the continuity of the inter-tooth equal period swell is 5,11 tools. At the time of marking, it is -1 for an integral multiple of the number of cutters.
From the above three cases, when machining a left helical gear with a cutter, the continuity of periodic waviness between teeth is an integral multiple of the number of cutters when M = -1 in the formula Z = H × N + M. The number of tool marks is -1.

Next, although illustration is omitted, when a 27-tooth gear with right-handed twisting is machined with a four-thread cutter, M in the equation Z = H × N + M is −1, and the continuity of the inter-tooth equal period waviness is 3, 7 At the time of tool mark, the number of tool marks is -1 with respect to an integral multiple of the number of cutters.
Next, although illustration is omitted, when a left-handed 34-tooth gear is machined with a 5-cutter, M in the formula Z = H × N + M is −1, and the continuity of the inter-tooth equal period undulation is 4,9. At the time of tool mark, the number of tool marks is -1 with respect to an integral multiple of the number of cutters.
Next, although illustration is omitted, when a 47-tooth gear is machined with a 6-cutter, M in the formula Z = H × N + M is −1, and the continuity of the inter-tooth regular waviness is 5,11 tool marks And −1 for an integral multiple of the number of cutters.
From the above three cases, when machining a left helical gear with a cutter, the continuity of periodic waviness between teeth is an integral multiple of the number of cutters when M = -1 in the formula Z = H × N + M. The number of tool marks is -1.

Next, although not shown in the figure, when machining a right-twisted 21-tooth gear with a four-thread cutter, M in the formula Z = H × N + M is +1, and the continuity of the inter-tooth equal period waviness is 5, 9 tools. When marking, the number of tool marks is +1 with respect to an integral multiple of the number of cutters.
Next, although not shown in the drawing, when machining a left-handed 36-tooth gear with a 5-thread cutter, M in the formula Z = H × N + M is +1, and the continuity of the inter-tooth equal period swell is 6,11 tools. When marking, the number of tool marks is +1 with respect to an integral multiple of the number of cutters.
Next, although not shown in the figure, when a 43-tooth gear is machined with a 6-thread cutter, M in the formula Z = H × N + M is +1, and the continuity of the inter-tooth equal period waviness is 7 and 13 tool marks. Yes, +1 for an integer multiple of the number of cutters.
From the above three cases, when machining the left helix gear with a cutter, the continuity of the periodic waviness between teeth is an integral multiple of the number of cutters when M = + 1 in the formula Z = H × N + M. In contrast, the number of tool marks is +1.

  Here, FIG. 23 summarizes the paragraphs 0112 to 0115 in a list. Thus, it can be seen that the continuity of the periodical waviness between teeth is based on a simple law.

Next, a description will be given of a work specification written so that an operator can easily select an appropriate machining specification.
FIG. 24 (a) is an example of a work specification that clearly shows machining conditions that are prohibited from being set in the gear cutting step when machining a 44-tooth left helical gear with a 5-thread cutter. The feed pitch Vf that does not satisfy the condition of N2 × H + 1 can be easily recognized.
FIG. 24B is an example of a work specification document that clearly shows the machining conditions that are prohibited from being set in the gear cutting step when machining a 44-tooth right-hand helical gear with a 5-thread cutter. The feed pitch Vf that does not satisfy the condition of N2 × H-1 can be easily recognized.
FIG. 25A is a work specification that clearly shows the machining conditions that can be set in the gear cutting step, and the machining conditions satisfying T = N2 × H-1 when machining a 44-tooth left helical gear with a 5-thread cutter. Is specified, and the operator can easily recognize the feed pitch Vf that can be processed.
FIG. 25 (b) is a work specification document that clearly shows the machining conditions that can be set in the gear cutting step, and clearly shows the machining conditions for T = N2 × H + 1 when machining a 44-tooth right-hand helical gear with a 5-cutter. The feed pitch Vf that can be processed by the operator can be easily recognized.

The gear machining method according to the embodiment of the present invention has the following operational effects.
That is, Z = H × N1 + M. In the case of a helical gear having a left-handed twist, when M = −1, a feed pitch Vf that does not satisfy T = N2 × H + 1 is set, and when M = + 1 By setting the feed speed V that does not satisfy T = N2 × H−1, the undulations formed on each tooth surface are continuously smooth with few steps between the tooth surfaces, and the periodicity of the undulations. Are arranged so as not to be arranged as tool marks that are maintained as a whole.
Also, Z = N2 × H + M, and in the case of a right helical gear, when M = −1, a feed pitch Vf that does not satisfy T = N2 × H−1 is set, and when M = + 1 By setting the feed pitch Vf that does not satisfy T = N2 × H + 1, the waviness formed on each tooth surface is smoothly smooth with few steps between the tooth surfaces, and the periodicity of the waviness Are arranged so as not to be arranged as tool marks that are maintained as a whole.

  Therefore, the gear machining method according to the embodiment of the present invention can effectively suppress the ghost sound generated unexpectedly at the stage of gear cutting by a simplified simple method. It is possible to reduce the number of man-hours by reducing an excessive burden caused by extra polishing for eliminating noise.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be implemented with appropriate modifications.
For example, in the present embodiment, the processing method for adjusting the cutter feed pitch to suppress the ghost sound at the gear cutting stage has been described. However, the present invention was not intended to exclude a finishing process such as shaving. A step of removing the tool mark formed in the gear cutting step by shaving or the like later can also be executed. Even when a shaving process or the like is performed, the number of finishing processes can be reduced by implementing the present invention and cutting gears in advance so as to suppress the ghost sound.

2 Cutter 3 Gear N1, N2 Arbitrary positive integer M Remaining integer part H Number of cutters T Number of tool marks
Vf Cutter feed pitch per gear rotation (mm / gear rotation)
Z Number of teeth of gear m Right angle module δ Length of one tooth meshing β Torsion angle

Claims (13)

Z = H × N1 + M, where Z is the number of teeth of a gear that is a helical gear, H is the number of cutters that cut the tooth surface of the gear, N1 is any positive integer, and M is the remaining integer part.
In the case where N1 is set so that the absolute value of M is the smallest value,
A specification determination step for determining whether or not any of M = ± 1 is satisfied;
A gear cutting step that performs gear cutting with a combination of the number of teeth Z and the number of threads H satisfying any of M = ± 1,
The length of one tooth meshing δ in the direction along the width direction of the gear is set, and the feed pitch of the cutter per rotation of the gear is Vf (mm / gear rotation) ,
The number of tool marks T of the cutter formed in one tooth meshing length δ,
A tool mark number calculating step of rounding off T ′ = δ / Vf to obtain an integer.
The gear cutting step includes
Arbitrary natural number is N2, and the remaining integer part is K.
When expressed as T = N2 × H + K,
A helical gear machining method characterized by setting a feed pitch Vf that does not satisfy T = N2 × H + 1 or T = N2 × H−1 and gearing. The twist angle of the gear is β, the tooth right angle module is m,
δ = πm / sin β
The method for machining a helical gear according to claim 1, wherein: In the case where the gear is a left-handed helical gear,
3. The helical gear machining method according to claim 1, wherein when M = -1, gear feed is performed by setting a feed pitch Vf that does not satisfy T = N2 * H + 1. 4. The helical gear machining method according to claim 3, wherein the feed pitch Vf is set so as to satisfy T = N2 × H−1 and gear cutting is performed. In the case where the gear is a left-handed helical gear,
3. The helical gear machining method according to claim 1, wherein when M = + 1, gear feed is performed by setting a feed pitch Vf that does not satisfy T = N2 × H-1. 6. The helical gear machining method according to claim 5, wherein the feed pitch Vf is set so as to satisfy T = N2 × H + 1 and gear cutting is performed. In the case where the gear is a right-handed helical gear,
3. The helical gear machining method according to claim 1, wherein when M = -1, gear feed is performed by setting a feed pitch Vf that does not satisfy T = N2 * H-1. The helical gear machining method according to claim 7, wherein the feed pitch Vf is set so as to satisfy T = N2 × H + 1 and gear cutting is performed. In the case where the gear is a right-handed helical gear,
3. The helical gear machining method according to claim 1, wherein when M = + 1, the feed pitch Vf that does not satisfy T = N2 × H + 1 is set and gear cutting is performed. The helical gear machining method according to claim 9, wherein the feed pitch Vf is set so as to satisfy T = N2 × H−1 and gear cutting is performed. 11. The helical gear according to claim 1, wherein gear cutting is performed based on a work specification capable of recognizing a feed pitch Vf that does not satisfy the condition of T = N2 × H ± 1. Processing method.   The helical gear machining method according to claim 11, wherein the work specifications clearly indicate machining conditions prohibited from being set in the gear cutting step.   The helical gear machining method according to claim 11, wherein the work specifications clearly indicate machining conditions that can be set in the gear cutting step.

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