JP2001198730A - Worm working method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To work a worm to have correct tooth form in a short working time. SOLUTION: An end mill-shaped tool 20 is driven to rotate around its rotation axial line Q, the rotation axial line Q is tilted for a specified angle in one direction from a perpendicular line N to a center axial line O of the work 10 in a plane R including the center axial line O, and the tool 20 is moved in parallel to the center axial line O at a porportional speed to a rotation speed of the work 10 to process a first tooth surface 16 by a working surface 21 at an outer circumference of a tip part of the tool 20. As the rotation axial line Q is tilted for a specified angle in the opposite direction, the tool 20 is moved in parallel to the center axial line O at a proportional moving speed to the rotation speed of the work 10 to work a second tooth surface 17. Working to the first tooth surface 16 and the second tooth surface 17 may be conducted in a first plane Sa parallel to the center axial line O of the work 10 and offset in one direction for a specified distance, or in a second plane Sb offset in the opposite direction for a specified distance. This invention is also applicable to working a dual lead worm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for processing a cylindrical worm used in combination with a worm wheel.

[0002]

2. Description of the Related Art FIG.
As shown in (1), a method of turning the first tooth surface 1a, the second tooth surface 1b, and the tooth bottom 1c by aligning the cutting edge surface of the trapezoidal cutting tool 2 with the plane including the central axis O of the worm 1 (referred to as type 1) , FIG.
(See FIG. 6A), a method of turning the tooth surfaces 3a, 3b and the tooth bottom 3c by aligning the cutting surface of the trapezoidal cutting tool 4 with a plane orthogonal to the lead wire of the worm 3 (referred to as FIG. b)), a method of cutting the tooth surfaces 5a, 5b and the tooth bottom 5c by setting the rotation center plane 6b of the both-pan milling cutter 6 rotating about the axis 6a along the lead of the worm 5 (3).
6 (c)), and a part of the first tooth surface 7a and a part of the tooth bottom 7c by a trapezoidal first single-edged cutting tool 8a offset by a predetermined distance in one direction from a plane including the central axis O of the worm 7. Then, the second tooth surface 7b and the rest of the root 7c are turned by a trapezoidal second single-edged cutting tool 8b offset by a predetermined distance in the opposite direction from the above-mentioned plane (referred to as type 4).
FIG. 6D). According to this type 4, each tooth surface 7
6D, the cross section perpendicular to the central axis O becomes an involute curve 9a having a circle 9 whose radius is the above-mentioned predetermined distance as a base circle.
Since a and 7b are convex surfaces, there is an advantage that meshing with the worm wheel does not deteriorate even if there is some processing error or assembly error.

[0003]

The first and second forms are turning, and the cutting is performed in a large number of times for the difference in the processing, so that the processing time is increased, which is not suitable for mass production. Type 4 is not suitable for mass production, because it processes one side at a time in addition to the problems of types 1 and 2 and increases the time and labor required for bite setting. Form 3 is suitable for mass production because it can be machined by one cut, but there is a problem that the tooth forms of the tooth surfaces 5a and 5b are broken. That is, the both-pan milling cutter 6 has a large length in the direction along the lead wire of the worm 5, and furthermore, FIG.
In FIG. 6C, the rotation center plane 6b of the milling cutter 6 is a straight line, whereas the lead wire of the worm 5 is a part of a sine curve. In this case, the rotation center plane 6b does not coincide with the lead wire. For this reason, since the milling cutter 6 processes the parts of the tooth surfaces 5a and 5b that should not be processed, the shapes of the tooth surfaces 5a and 5b are out of order, and the meshing with the worm wheel is deteriorated. There is a problem. This problem is particularly remarkable when the lead angle of each tooth surface is large. An object of the present invention is to solve such a problem.

[0004]

For this purpose, a worm machining method according to the present invention is directed to a worm machining method in which a helical tooth is formed on a cylindrical outer periphery. Drive around the axis, in a state where this rotation axis is inclined at a predetermined angle in one direction from a line orthogonal to the center axis in a plane including the center axis of the worm,
The tool is relatively moved in parallel with the center axis at a speed proportional to the rotation speed of the worm about the center axis, and the first surface of the tooth portion is processed by the processing surface on the outer periphery of the tip of the tool.
A tooth surface is machined, and then the worm rotates about the center axis while the rotation axis is inclined at a predetermined angle in a direction opposite to the one direction from a line perpendicular to the center axis in the plane. The tool is relatively moved parallel to the center axis at a moving speed proportional to the speed, and the second tooth surface of the tooth portion is machined by the machining surface on the outer periphery of the tip of the tool. . Since the length of the end mill type tool in the direction along the lead wire becomes shorter, at a position away from the rotation axis of the tool in the lead wire direction, the tool quickly separates from each tooth surface, and it is not possible to machine each tooth surface. Disappears.
Further, if the inclination angle of the rotation axis of the tool from a line perpendicular to the central axis of the worm is changed, the pressure angle of the worm also changes.

[0005] Further, a method for processing a worm according to the present invention comprises:
In a worm machining method in which a helical tooth portion is formed on a cylindrical outer periphery, an end mill-type tool is rotationally driven around its rotation axis, and the rotation axis is parallel to a central axis of the worm in one direction. In a state where the tool is inclined at a predetermined angle in one direction from a line orthogonal to the center axis within a first plane offset by a predetermined distance, the tool is moved to the center at a speed proportional to the rotation speed of the worm about the center axis. The first tooth surface of the tooth portion is machined by a machining surface on the outer periphery of the tip end of the tool by being relatively moved in parallel with the axis, and then the rotation axis is parallel to the first plane and in the opposite direction to the center axis. In a state in which the worm is inclined at a predetermined angle in a direction opposite to the one direction from a line orthogonal to the center axis in a second plane offset by a predetermined distance from the worm, the worm is centered on the center axis. The method is characterized in that the tool is relatively moved in parallel with the central axis at a moving speed proportional to the rolling speed, and the second tooth surface of the tooth portion is machined by the machining surface on the outer periphery of the tip of the tool. Is also good. According to this invention, similarly to the invention of the preceding paragraph, the tool does not machine each tooth surface at a position away from the rotation axis of the end mill type tool in the lead direction, and the inclination angle of the rotation axis of the tool can be changed. For example, in addition to the change of the worm pressure angle, a cross section orthogonal to the central axis of each tooth surface becomes an involute curve, and each tooth surface becomes a convex surface.

It is preferable that the processing surface on the outer periphery of the tip of the tool according to the second aspect of the invention has a tapered conical shape.

[0007] The invention of the preceding claims is characterized in that, when machining the first tooth surface and the second tooth surface, the inclination angles of the rotation axis of the tool from the line N perpendicular to the central axis are the same angles opposite to each other. The moving speed of the tool with respect to the rotation speed of the worm in each machining may be the same. Alternatively, when machining the first tooth surface and the second tooth surface, the respective inclination angles of the rotation axis of the tool from a line orthogonal to the center axis are different angles that are opposite to each other. The respective moving speeds of the tool with respect to the rotation speed of the worm may be different values related to the difference in the inclination angle.

[0008] The worm processing apparatus according to the present invention comprises:
A bed, a feed table and a column supported on the bed so as to be relatively movable in the X direction, and a turntable supported on the column so as to be rotatable around a rotation axis orthogonal to the X direction. A spindle head movably supported in an A direction orthogonal to the rotation axis on the turntable; and a spindle head mounted on the table so as to be rotatable about an axis parallel to the X direction. A spindle that coaxially supports and drives the worm to be rotated, and an end mill type that is rotatably supported by the spindle head so as to be rotatable around a rotation axis parallel to the direction A and is driven to rotate to process a tooth portion on the worm. A tool spindle for mounting a tool at a tip portion is provided. The tool spindle with the end mill type tool attached at the tip is driven to rotate, and the spindle head, which supports the worm in each state where the spindle head is tilted at a predetermined angle in one direction and the opposite direction to the X direction by the rotary table, is driven to rotate. By appropriately moving the spindle head and the headstock in the X direction at a speed proportional to the rotation speed of the headstock with an appropriate cut in the tool, each tooth surface is machined on the worm.

It is preferable that the feed table and the column according to the above-mentioned invention are relatively movable even in a direction parallel to the rotation axis. In this way, the rotation axis of the tool can be offset with respect to the center axis of the worm, and the tooth surface to be machined becomes convex.

[0010]

According to the present invention, each tooth surface is machined by relatively moving the rotation axis of the end mill type tool within a plane including the center axis of the worm. In addition, since the length of the tool in the direction along the lead wire is shortened, the tool is quickly separated from each tooth surface at a position away from the rotation axis in the lead line direction and does not machine each tooth surface. Therefore, since a part which should not be processed is originally processed and the shape of each tooth surface does not change, a worm having an accurate tooth profile can be processed in a short processing time. Further, if the inclination angle of the rotation axis of the tool from the line perpendicular to the center axis of the worm is changed, the pressure angle of the worm also changes, so that a worm with a different pressure angle can be machined with one tool.

According to the present invention, the rotation axis of the end mill type tool is parallel to the center axis of the worm and is offset by a predetermined distance in one direction and in a second plane parallel to and offset by a predetermined distance in the opposite direction. Each tooth surface may be machined by moving it.According to this, in addition to the effects of the invention described in the preceding paragraph, the cross section orthogonal to the central axis of each tooth surface becomes an involute curve, and accordingly each tooth surface becomes Because of the convex surface, the engagement with the worm wheel does not deteriorate even if there is some processing error or assembly error.

According to the end mill type tool having a tapered conical shape on the outer peripheral surface of the tip end portion, a worm having a narrow tooth bottom can be machined even when the diameter of the tool is increased. The difference in the inclination angle of the tool when the first and second tooth surfaces are formed can be reduced.

[0013] When machining the first tooth surface and the second tooth surface, the inclination angles of the rotation axis of the tool from the line orthogonal to the center axis are opposite to each other, and the angles of the worms in the respective operations are different. When the moving speed of the tool with respect to the rotational speed is the same, a normal worm having the same lead angle and lead at each tooth surface is formed.

In addition, when the first tooth surface and the second tooth surface are machined, the inclination angles of the rotation axis of the tool from the line perpendicular to the center axis are mutually different and different angles. According to a different value of the moving speed of the tool with respect to the rotation speed of the worm, which is related to the difference of each inclination angle, a multiple lead worm having a different pressure angle and a different lead from each tooth surface is formed.

According to the worm machining apparatus of the present invention, since the circumference of the tip of the tool spindle on which the tool is mounted is compact, the tool is inclined at predetermined angles in one direction and the opposite direction with respect to the center axis of the worm. There is virtually no restriction to move parallel to the central axis. Therefore, processing is extremely easy.

According to the above-mentioned invention, the feed table and the column can be relatively moved even in the direction parallel to the rotation axis. It is possible to obtain a worm that does not deteriorate the engagement with the worm wheel to be combined even if there is an error or an assembly error.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A worm processing method and a worm processing apparatus according to the present invention will be described below with reference to the accompanying drawings.
First, referring to FIG. 1 and FIG.
An embodiment will be described. The worm 10 includes a central portion 11 and both end portions 12 and 13.
The first tooth surface 16, the second tooth surface 17, and the tooth root 18 by the tool 20
The spiral tooth portion 15 is formed by forming a spiral groove formed of the spiral groove. The plane R including the central axis O of the worm 10 (see FIG. 2), that is, the pressure angles of the tooth surfaces 16 and 17 on the paper surface of FIG.
b, αa = αb in a normal worm. In the first embodiment, a case where such a normal worm is processed will be described. In addition, each tooth surface 16, 17
Are T0 and T1, and in this embodiment, T0-T
1 = 0.

The tool 20 used for forming the spiral groove is an end mill type rotary tool such as an end mill or a small grinding wheel, and has a first tooth surface 16 and a second tooth surface on its outer periphery at its tip. A conical processing surface 21 for processing the tooth 17 and a distal end surface 22 for processing the tooth bottom 18 are formed at the distal end. The vertex angle β of the processing surface 21 is a value smaller than twice (= 2αa) the pressure angle of each tooth surface 16.17. This tool 20
Is defined by setting the rotation axis Q in a plane R (see FIG. 2) including the central axis O of the worm 10, that is, in the plane of FIG. 1, and first inclining by a predetermined angle δa in one direction from a line N orthogonal to the central axis O. In this state, the worm 10 is relatively moved in parallel with the central axis O at a speed proportional to the rotation speed of the worm 10, and the first tooth surface 16 of the tooth portion 15 and the tooth bottom 18 are formed by the processing surface 21 and the front surface 22 on the outer periphery of the tip. Process part of. Next, in a state where the rotation axis Q is also inclined by a predetermined angle δb (= δa) in the opposite direction from a line N orthogonal to the center axis O in the plane R, the center axis O is rotated at a speed proportional to the rotation speed of the worm 10. The second tooth surface 17 of the tooth portion 15 and the rest of the tooth bottom 18 are machined by the processing surface 21 and the end surface 22 on the outer periphery of the tip portion.

Next, with reference to FIGS. 4 and 5, a description will be given of a worm processing apparatus used for this processing. On the bed 30 of the worm processing device, a feed table 31
And is reciprocally driven by an X-direction feed motor (not shown). A column 32 is supported and supported on a rear side of the feed table 31 in a horizontal Y direction orthogonal to the X direction. (Omitted). A headstock 35 and a tailstock 38 are placed on the feed table 31 so as to face each other in the X direction, and are rotatably supported by the headstock 35 about the axis O parallel to the X direction. The spindle 36 provided with the chuck 37 is rotationally driven by a spindle motor (not shown), and a tailstock 38 is provided with a center 39 coaxially with the spindle 36.

On the upper part of one side of the column 32 on the side of the feed table 31, a turntable 40 is supported rotatably about a rotation axis P parallel to the Y direction, and is rotated by a drive motor (not shown). A spindle head 41 is guided and supported on the turntable 40 so as to be movable in the direction A orthogonal to the rotation axis P, and is reciprocally driven by a feed motor (not shown). The spindle head 41 has a rotation axis P
The tool spindle 42 is rotatably supported about a rotation axis Q located in a plane parallel to the direction A, and is rotated at a high speed by a spindle motor (not shown). It is supposed to be.

The worm 10 to be processed has one end 1
2 is gripped by a chuck 37, and the other end 13 is supported by a center 39 and mounted coaxially with the main shaft 36. First, the column 32 is moved in the Y direction to a position where the rotation axis Q of the tool spindle 42 and the tool 20 mounted on the tip thereof is within the plane R including the main shaft 36 and the central axis O of the worm 10 gripped by the main shaft 36. By rotating the turntable 40, the rotation axis Q of the spindle head 41 is inclined in a direction shown in FIG. 1 by a predetermined angle δa with respect to a line N orthogonal to the central axis O, and the feed table 31 is moved in the X direction. The position of the rotation axis Q is extended to one end 12 of the worm 10.
Position. And the tool spindle 42
Is rotated, the spindle head 41 is moved in the direction A to give a predetermined cut to the tool 20, and the spindle 36 is rotated.
The worm 10 is rotated, and the feed table 31 is moved leftward at a feed speed such that the feed amount per rotation of the worm 10 becomes the lead of the tooth portion 15, and the tooth is moved by the machining surface 21 and the tip end surface 22 of the tool 20. First tooth surface 16 of part 15
And a part of the tooth bottom 18 is processed. Next, the spindle head 41 is retracted, and its rotation axis Q is inclined in the opposite direction to the line N by a predetermined angle δb (= δa) (see the two-dot chain line 20A in FIG. 1), and the feed table 31 is moved to the same position as described above. And Then, as described above, a predetermined cut is given to the tool 20, and the feed table 31 is moved to
The second tooth surface 17 of the tooth portion 15 and the rest of the tooth bottom 18 are machined by the first and the tip surface 22.

The predetermined angle δa is a value close to αa− (β / 2), but is not the same. That is, the tangent of the machined surface 21 of the tool 20 to the machined first tooth surface 16 is the generatrix 21a of the machined surface 21 shown in FIG. The inclination angle of the rotation axis Q of the spindle head 41 with respect to N is αa−
If it is set to (β / 2), the processing surface 21 will cut the first tooth surface 16 too much. Therefore, the predetermined angle δa in the plane R is slightly smaller than αa− (β / 2),
The value may be determined experimentally. The same applies to the second tooth surface 17.

According to the first embodiment described above, each one
Since the first tooth surface 16 and the second tooth surface 17 can be machined by the number of cuts, the machining time can be shortened. In addition, the end mill type tool 20 has a shorter tool length in the direction along the lead wire. At a position away from the axis Q in the lead line direction, the tool 20 quickly separates from the tooth surfaces 16 and 17 and no longer processes each tooth surface. Therefore, there is no possibility that the shape of each of the tooth surfaces 17 and 18 will be changed by processing a portion which should not be processed, and the worm tooth profile obtained will be accurate.

If the inclination angle of the rotation axis Q of the tool 20 from the line N perpendicular to the central axis O of the worm 10 is changed, the pressure angle of the worm 10 also changes. The worm 10 can be processed.

In the above-described first embodiment, the tool 2
The machining surface 21 on the outer periphery of the leading end of the taper 0 has a tapered conical shape. With this configuration, even when the diameter of the tool 20 is increased, the worm 10 having a narrow tooth bottom 18 can be machined. However, the present invention can be implemented using a tool having a cylindrical processing surface.

When machining the tooth surfaces 16 and 17, the tool 2
Since the rotation axis Q of 0 is inclined, unevenness occurs on the tooth bottom 18, so that the tooth bottom 18 needs to be deeper than the regular tooth bottom. The irregularities can be alleviated by forming the tip end surface 22 of the tool 20 into a conical shape having a large apex angle as shown in FIG.

In the first embodiment described above, the tool 20
The feed table 31 is moved in the X-direction while the rotation axis Q of the tooth is positioned in the plane R to process the tooth surfaces 16 and 17, but in the second embodiment shown in FIG. 20
The feed table 31 is moved in the X direction while the rotation axis Q is positioned in the first plane Sa, which is parallel to the central axis O of the worm 10 and is offset by a predetermined distance in one direction, to process the first tooth surface 16. The rotation axis Q of the tool 20 to the first plane Sa.
In that the feed table 31 is moved in the X direction while being positioned in the second plane Sb, which is parallel to and in the opposite direction and is offset by a predetermined distance from the central axis O, to process the second tooth surface 17. Since the other configuration is the same as that of the first embodiment, this difference will be mainly described. The worm processing equipment used for processing is the first
It is completely the same as that of the embodiment.

The worm 10 to be machined is mounted coaxially with the main shaft 36 as in the case of the first embodiment.
The column 32 is moved in the Y direction so that the rotation axis Q of the tool spindle 42 and the end mill type tool 20 mounted on the tip thereof are parallel to the center axis O of the worm 10 (thus parallel to the plane R in the first embodiment). ), The rotary table 40 is rotated to set the rotation axis Q of the spindle head 41 with respect to the line N orthogonal to the center axis O in the plane R by setting the position within the first plane Sa offset by a predetermined distance d in one direction. The feed table 31 is tilted in one direction by a predetermined angle δa ′ (the angle projected on the paper surface of FIG. 1), and the position of the feed table 31 in the X direction is set so that the extension of the rotation axis Q extends to one end 12 of the worm 10. . Then, similarly to the first embodiment, the tool spindle 42 is rotationally driven to make a predetermined cut in the tool 20, the worm 10 is rotated, and the worm 10 is rotated.
The feed table 31 is moved leftward at a feed speed such that the feed amount per rotation becomes the lead of the tooth portion 15 and the tool 20 is moved.
The first tooth surface 16 of the tooth portion 15 and a part of the tooth bottom 18 are processed by the processing surface 21 and the front end surface 22. Next, similarly to the first embodiment, the spindle head 41 is retracted, the column 32 is moved in the Y direction, and the rotation axis Q of the tool spindle 42 and the end mill type tool 20 mounted on the tip thereof is shifted to the first plane Sa. And a position within the second plane Sb offset by a predetermined distance d from the center axis O in the opposite direction to the center axis O, and the rotation axis Q of the tool 20 with respect to the line N is represented by δb ′ (= δa ′).
And the feed table 31 is set at the same position as described above, a predetermined cut is given to the tool 20, the feed table 31 is moved, and the toothed portion 15 of the tooth portion 15 is moved by the machining surface 21 and the tip end surface 22 of the tool 20. The remaining two tooth surfaces 17 and root 18 are machined. The inclination angle δa ′ of the rotation axis Q of the spindle head 41 with respect to the line N may be experimentally determined as described above.

According to the second embodiment, each tooth surface 1
The cross sections orthogonal to the central axis O of the reference numerals 6 and 17 are involute curves based on a circle whose radius is the offset distance d as in the case of the above-described prior art type 4, and the tooth surfaces 16 and 17 are convex surfaces. Becomes Therefore, the worm 10 obtained according to the second embodiment does not deteriorate the engagement with the worm wheel to be combined even if there are some processing errors and assembly errors. Although the offset distances d when processing the tooth surfaces 16 and 17 are the same, the present invention can be practiced with the offset distances d being different.

In the first and second embodiments described above,
Although the case where a normal worm is machined by the present invention has been described, in the third embodiment described below, a multiple lead worm in which the leads of the first tooth surface 16 and the second tooth surface 17 are different is machined by the present invention. The case will be described. Such a double lead worm is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-309244.
As described in the publication, since the tooth thickness changes as it advances in the axial direction, it is used to adjust the backlash between the worm wheel and the worm wheel that moves in the axial direction.

In the third embodiment, the first tooth surface 16
Lead T0, pressure angle αa and lead T of the second tooth surface 17
1 and the pressure angle αb are different from each other, and therefore a line N orthogonal to the central axis O when machining each tooth surface 16, 17
The inclination angles δa, δb of the rotation axis Q of the tool 20 and the moving speed of the feed table 31 are different from those in the first embodiment. When meshing with a worm wheel cut by a standard hob, there is a relationship between the lead of each tooth surface and the pressure angle: T0 · cosαa = T1 · cosαb. The worm processing device used for the processing is exactly the same as that of the first embodiment.

The worm 10 to be machined is mounted coaxially with the main shaft 36 as in the case of the first embodiment.
The column 32 is positioned and the machining surface 21 of the tool 20 is
The first tooth surface 16 of the tooth portion 15 and the root 1
Process part of 8. In this case, the inclination angle δa is also αa −
The value is slightly smaller than (β / 2), and the value may be determined experimentally. The moving speed of the feed table 31 is set to a value such that the feed amount per rotation of the worm 10 becomes the lead T0 of the first tooth surface 16. Subsequent machining of the second tooth surface 17 and the tooth bottom 18 is performed in the same manner as described above. In this case, the inclination angle δb is a value slightly smaller than αb− (β / 2), Should be determined. The moving speed of the feed table 31 is set to a value such that the feed amount per rotation of the worm 10 becomes the lead T1 of the second tooth surface 17. Thus, the worm 10 to be processed is a double lead worm.

Also in the third embodiment, the tooth surfaces 16 and 17 are machined by offsetting the rotation axis Q of the tool 20 from the center axis O of the worm 10 as in the second embodiment. By doing so, a double lead worm in which the tooth surfaces 16, 17 are convex can be obtained.

As shown in the above embodiments, in the present invention, since each tooth surface is separately processed, the processing time is increased by that amount. However, since each tooth surface is machined with the same end mill-type tool mounted on the tool spindle, the tool needs to be set only once, and the machining time is reduced by that much. In each of the embodiments described above, only one worm is described. However, the present invention can be applied to two or multiple worms.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a first embodiment of a worm processing method according to the present invention.

FIG. 2 is a plan view of the embodiment shown in FIG.

FIG. 3 is a plan view corresponding to FIG. 2 of a second embodiment of the worm machining method according to the present invention.

FIG. 4 is a front view showing an embodiment of a worm processing apparatus according to the present invention.

FIG. 5 is a side view of the embodiment shown in FIG.

FIG. 6 is an explanatory view of a conventional worm processing method.

[Description of Signs] 10: worm, 15: tooth portion, 16: first tooth surface, 17 ...
2nd tooth surface, 20 ... tool, 21 ... machined surface, 30 ... bed,
31 ... feed table, 32 ... column, 35 ... headstock, 3
6 ... spindle, 40 ... turntable, 41 ... spindle head, 4
2 ... Tool spindle, N ... Line, O ... Center axis, P ... Rotation axis, Q ... Rotation axis, R ... Plane, Sa ... First plane, Sb
... First plane.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshiharu Inakuma 1-1-1, Asahi-cho, Kariya-shi, Aichi Prefecture Inside Toyota Machine Works Co., Ltd. (72) Inventor Teruwa Nakajima 3-5-2, Minamisenba, Chuo-ku, Osaka-shi, Osaka No. Koyo Seiko Co., Ltd. (72) Osamu Ogawa 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Seiji Sano 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (Reference) 3J009 DA10 DA20 EA06 EA19

Claims (7)

[Claims] In a worm machining method in which a helical tooth is formed on a cylindrical outer periphery, an end mill-type tool is driven to rotate around a rotation axis thereof, and the rotation axis is set to a center axis of the worm. In a state where the tool is inclined at a predetermined angle in one direction from a line orthogonal to the center axis in a plane including the tool, the tool is positioned parallel to the center axis at a speed proportional to the rotation speed of the worm about the center axis. The tool is moved to process the first tooth surface of the tooth portion with the processing surface on the outer periphery of the tip of the tool, and then the rotation axis is moved in a direction opposite to the one direction from a line orthogonal to the center axis in the plane. In a state in which the tool is inclined at a predetermined angle, the tool is relatively moved in parallel with the center axis at a movement speed proportional to the rotation speed of the worm about the center axis, and the processing surface on the outer periphery of the tip of the tool is used. Previous A method of processing a worm, comprising processing a second tooth surface of a toothed portion. 2. A worm machining method in which a helical tooth is formed on a cylindrical outer periphery, wherein an end mill-type tool is driven to rotate around its rotation axis, and the rotation axis is aligned with the center axis of the worm. In a first plane parallel and offset by a predetermined distance in one direction and inclined at a predetermined angle in one direction from a line orthogonal to the center axis, at a speed proportional to the rotation speed of the worm about the center axis. The tool is relatively moved in parallel with the central axis to machine the first tooth surface of the tooth portion with the machining surface on the outer periphery of the tip of the tool, and then the rotation axis is parallel to the first plane and opposite thereto. In a second plane offset by a predetermined distance from the central axis in a direction, and in a state inclined at a predetermined angle in a direction opposite to the one direction from a line perpendicular to the central axis, before the center of the central axis. The tool is relatively moved parallel to the central axis at a moving speed proportional to the rotation speed of the worm, and the second tooth surface of the tooth portion is processed by the processing surface on the outer periphery of the tip of the tool. Worm processing method. 3. The worm machining method according to claim 1, wherein a machining surface on an outer periphery of a tip portion of the tool has a tapered conical shape. 4. An inclination angle of a rotation axis of the tool from a line N orthogonal to the center axis when machining the first tooth surface and the second tooth surface is the same angle opposite to each other;
Further, the moving speed of the tool with respect to the rotational speed of the worm in each processing is the same.
The worm processing method according to claim 3. 5. An inclination angle of a rotation axis of the tool from a line orthogonal to the central axis when machining the first tooth surface and the second tooth surface is a different angle opposite to each other. The worm processing method according to any one of claims 1 to 3, wherein the respective moving speeds of the tool with respect to the rotation speed of the worm during the processing of (i) are different values related to the difference in the inclination angle. 6. A worm processing apparatus used for carrying out the worm processing method according to claim 1, wherein the feed table is supported on the bed so as to be relatively movable in the X direction. And a column, a turntable rotatably supported on the column about a rotation axis orthogonal to the X direction, and a spindle head supported movably on the turntable in an A direction orthogonal to the rotation axis. A spindle that is rotatably supported by a spindle head mounted on the table and that is rotatably supported about an axis parallel to the X direction and that is driven to rotate coaxially; A tool spindle which is rotatably supported and rotatable about a parallel rotation axis and is rotatably driven to mount an end mill-type tool for processing a tooth portion on the worm at a tip end thereof. Worm processing equipment. 7. The worm processing apparatus according to claim 6, wherein the feed table and the column are relatively movable even in a direction parallel to the rotation axis.