JPS5847290B2 - Lathe for manufacturing spherical hob for gear generation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lathe for manufacturing spherical hobs for gear generation.

As shown in Figures 1 and 2, the hob blades 1 are arranged in a spiral manner on a spherical surface, and by rotating around the axis, any cross section represents the rotation of a virtual involute gear. Since the cutting rotation of the spherical hob 2 represents the meshing of gears, generating hobbing of internal gears, which was impossible with the cylindrical hob, is now possible, as shown in Figure 3.
Further, there is an advantage that alignment between the gear material and the hob 2, which is necessary in a fixed position hob for an internal gear, is not required as shown in FIG. 4.

However, since this hob 2 represents the rotation of a virtual gear by rotation, if the outer circumferential surface 1a and both side surfaces 1b of the hob blade 1 are removed in the same manner, the blade surface 1c will be damaged due to wear of the blade surface 1c. When grinding, the outer diameter of the hob becomes smaller,
It becomes impossible to create a tooth profile with the same shape and size as the tooth profile before grinding.

An object of the present invention is to provide a lathe for manufacturing a spherical hob which has the above-mentioned advantages and which can always create a tooth profile of the same shape and size even when the cutting surface is ground.

An embodiment embodying the present invention will be described below with reference to FIG.
' is actively rotated in the counterclockwise direction in Fig. 7.

Reference numeral 13 denotes a circular swivel base which is provided below the mounting position of the hob material 2', passing through the center of the hob material 2' and rotatable left and right about a line orthogonal to the axis of the support shaft 11. As shown in FIG. 6, a worm gear 14 is formed on the outer peripheral surface.

15 is a worm that meshes with the worm gear 14, and the rotation of the support shaft 11 is a virtual gear tooth number indexing mechanism 16;
It is transmitted via the transmission shaft 17 and the gear transmission mechanism 18, and rotates the swivel base 13 to the right or left.

In addition, the tooth number indexing mechanism 16 can adjust the rotational speed of the swivel base 13 by replacing the gears so as to match the rotation of the virtual gear caused by the rotation of the hob being cut.

Reference numeral 19 denotes a board mounted in a recess 20 on the top surface of the swivel base 13 so as to be movable back and forth, as shown in FIGS. 6a and 7, and is biased in the backward direction (in the direction of arrow P) by a spring 19a. .

Reference numeral 21 designates a blade fixing plate that is fixed and releasably attached to the upper surface of the base plate 19 using a non-limiting pin or the like, and 22 is a fixing member that is fixed to the swivel base 13 so as to straddle the blade fixing plate 21. .

Reference numeral 23 denotes a cutter mount fixed to the rear end of the upper surface of the cutter fixing plate 21, and a cutting tool 24.2 for cutting the hob material 2'.
5.26 is attached and fixed.

As shown in Fig. 15, the cutting tools include one in which the cutting tool has the shape of the tooth groove of an involute gear 24, one in which the tooth groove is equally divided into two parts 25, and one in the shape of a normal customer 26. used.

Next, we will explain the first half of the manufacturing process of the hob using the lathe configured as described above. This process involves cutting the hob material 2' into a spherical shape, cutting out a protrusion with an involute tooth profile in a spiral shape, and then cutting the hob material 2' into a spherical shape. In the process of cutting a blade groove, first, a block-shaped hob material 2', in which a mounting hole 3 and a key groove 4 have been formed in advance, is attached and fixed to the support shaft 11, and a blade is attached to the blade mount 23 by a regular vendor. Attach and fix the cutting tool 26.

Once this is done, the motor 12 is started.

Then, the support shaft 11 is rotated counterclockwise in FIG. 7, and the swivel table 13 is rotated clockwise in FIG. 6 about a line passing through the center of the hob material 2'. Therefore, the hob material 2' can be cut into a spherical shape as shown in FIG.

In this case, the outer diameter of this hob material 2' is m-
Cutting is performed so that Z+2.5・m+b.

Next, the cutting tool 26 is replaced with a cutting tool 24 having a tooth groove shape, and the outer circumferential surface of the hob material 2' is again cut.

In this case, a protrusion having an involute tooth profile in cross section is cut in a spiral shape on the outer periphery of the hob material 2' so that the rotation of the hob material 2' represents the rotation of a virtual involute gear.

In other words, every time the hob material 2' rotates, the tool 2
4 may be rotated around the center of the hob material 2' by one tooth of the virtual gear to perform cutting.

Therefore, if the number of teeth of the virtual gear is Z, the rotation angle φ of one tooth is as shown in FIG.
Adjust the rotation speed in step 3.

Therefore, when the hob material 2' cut in this manner rotates around the axis, it represents the rotation of a virtual gear having Z number of teeth.

Next, this hob material 2' is removed from the support shaft 11, and a suitable number of cutting grooves 5 parallel to the axis are cut into the hob material 2' by a milling machine (not shown), as shown in FIGS. 1 and 2. ′
Cutting is performed so that the outer circumferential surface is formed at equal intervals.

Therefore, the hob blade 1 continues spirally on the outer circumferential surface of the hob material 2', and the blade surface 1C forms an involute tooth profile.
is formed.

(See Fig. 16) Next, in the lathe of this embodiment, the outer circumferential surface 1a of the hob blade 1 is
No. 2 (hereinafter referred to as outer circumference No. 2), that is, a mechanism for taking relief from the outer circumferential surface 1a, is explained. 32 is the seventh
As shown in the figure, the cam is fixed to the shaft 35 at a position below the base plate 19, and as shown in FIG.
2, it is actively rotated via the second indexing mechanism 34, gear transmission mechanism 36, and bevel gears 37 and 38, which will be described later, and the follower 33 on the lower surface of the board 19 is slid on the outer periphery by the bias of the spring 19a. being touched.

As shown in FIG. 11, this cam 32 has a constant amount of change in the cam surface per unit angle, and
The change is suddenly restored, and one rotation causes the substrate 19 to advance at a constant speed via the follower 33 and then rapidly retreat.

Therefore, the cutting tool attached and fixed to the blade mount 23 also functions in the same way.

As shown in FIG. 5, 34 is a second indexing mechanism that transmits the rotation of the support shaft 11 to the cam 32, and controls the rotational speed of the cam 32 by exchanging gears.
The indexing ratio of numbering can be adjusted as desired.

Now, in order to take the outer circumference No. 2, attach and fix the hob material 2' to the support shaft 11 again, replace the cutting tool 24 with a normal selling tool 26, and place the tool 26 at the outer peripheral surface 1a position of the hob blade 1. Set to .

Next, the number 2 indexing mechanism 34 is adjusted to adjust the rotation speed of the cam 32.

In other words, the cutting tool 26 gradually protrudes toward the center of the hob material 2' in synchronization with the cycle in which the hob blade 1 appears in the cutting position, and suddenly returns to the pre-projection position just before the next hob blade 1 appears in the cutting position. The goal is to return to the original state.

In this case, when making the second cutting edge groove in the hob's axial direction with a conventional cylindrical hob, if the number of cutting edge grooves on the hob is N, the cam only needs to rotate by N rotations for one rotation of the hob, so the cutting edge groove Indexing gear ratio η.

If the mechanical constant is F, then η.

=FN. However, in the case of the second hole of a spherical hob, the pin 33 that contacts the cam 32 is fixed to the second hole base plate 19 as shown in FIG.
When the hob rotates by 1, the contact position shifts from T to T', and the hob cuts more by Δh per rotation.

Therefore, the cam 32 is rotated less by φ per rotation of the hob.

In other words, while the hob material 2' rotates once, the cutting tool 2π 26 rotates by z rad as described above, so if τ of this 2π is α and the number of cutting grooves 5 is N, the cam 32 rotates the hob material If the hob rotates only for one rotation of the hob, one cut can be made on the outer peripheral surface of each month of the spherical hob.

Therefore, the indexing ratio η1 is calculated by adjusting a with respect to the rotating hob blade 1 by adjusting the indexing ratio by the second takeout indexing mechanism 34 so that the indexing ratio becomes the same for one rotation of the hob material 2'. It is possible to accurately perform the second outer circumferential cutting work.

In addition, as shown in FIG. 11 and FIG.
Letting the outer diameter of ' be D and the angle of the second outer circumference, it can be found as follows.

Further, the depression amount ΔX of the outer circumference No. 2 with respect to the central angle θ of the hob material 2' is similarly determined as shown in FIG.

Next, to explain the mechanism for removing the side surface No. 2 of the hob blade 1 in the lathe of this embodiment, as shown in FIG. 22 is a pin hole transparently provided, 28 is a pin hole also transparently provided in the blade fixing plate 21, and both pin holes 27
．． A pin 29 can be inserted into 28 as shown in FIG.

When the blade fixing plate 21 is released from the base plate 19 and the pins 29 are inserted into the pin holes 27.2B, the blade fixing plate 21 can rotate around the pins 29.

That is, at this time, the blade fixing plate 21 and the blade mounting base 23 can rotate relative to the swivel base 13 around the center of rotation of the swivel base 13.

The id pin 30 protrudes from the lower surface of the rear end of the blade fixing plate 21, and is inserted into an oblique cam groove 31 formed in the base plate 19 so as to be movable back and forth. By doing so, the blade fixing plate 21 is moved to the first position with the pin 29 inserted into both pin holes 27 and 28 as the center.
As shown in Figure 0, it can be rotated counterclockwise.

Therefore, the blade mount 23 is also rotated counterclockwise around the pin 29, and this rotation causes the blade mount 23 to rotate counterclockwise around the pin 29.
The virtual gear represented by the hob material 2' is adjusted so that the semi-tooth groove-shaped bit 25 fixedly attached to the hob blade 1 is dislocated by the amount that the outer circumference 2 is lowered to become a thinner blade. Cutting is performed along the pitch circle.

That is, as shown in FIG. 17, the pitch circle P of the involute tooth profile when dislocated by ΔX.

The amount of change in the tooth thickness on C is expressed by the module m1, where the pressure angle is α.

Therefore, in order to obtain an involute tooth profile, the pitch circle P
, C soil can be used by reducing the arc tooth thickness by 2.ΔX-tanα.

Then, 2・△)” Angle ε for thinning by tan α
.

As shown in Figure 19, 2・△X・tanα is expressed as △S
, the central angle of the hob material 2' for dislocation by △X is θ,
If the length along the blade line of the hob blade 1 with respect to the central angle θ is G, then the following equation is obtained.

Therefore, the cutting tool 25 is at this angle ε.

The inclination angle ξ of the cam groove 31 is determined so that the side surface 1b of the hob 1 is cut along the pitch circle of the virtual gear.

Now, in order to remove side No. 2 of the hob blade 1, replace the cutting tool 26 with a half-toothed cutting tool 25, and connect the base plate 19 and the cutting tool fixing plate 2.
1, insert the pins 29 into both pin holes 27 and 28 as shown in FIG. 9, and set the cutting tool 25 at the side 1b position of the hob blade 1 as shown in FIG. The support shaft 11, swivel base 13, and cam 32 are rotated at the same speed as described above.

In this way, the cam 32 repeats a movement in which the substrate 19 advances at a constant speed and then rapidly retreats in synchronization with the cycle of each hob blade 1 coming to the cutting position.

Therefore, the cutting tool 25 fixedly attached to the blade mount 23 is also synchronized with the appearance period of the hob blade 1, and rotates around the pin 29 on the line passing through the center of the hob material 2, and then quickly returns to its original position. By repeating this, one side surface 1b of the hob blade 1 can be scraped off along the pitch circles P and C of the virtual gear represented by the hob material 2'.

After removing No. 2 on one side 1b in this way, set the hob material 2 on the support shaft 11 again so that the left and right sides of the hob material 2' are reversed, and repeat the same operation.
Depending on the number, the outer peripheral surface 1a of the hob blade 1 may be dislocated and thinned by the amount lowered.

Therefore, if the cutting quality of the hob blade 1 deteriorates due to wear due to generating gear cutting, the blade surface 1 should be adjusted so that the rake angle does not change.
When c is ground, the new blade surface 1c becomes a moon shape of an involute tooth profile which is shifted by the amount lower than the outer circumference No. 2 from the moon shape of the blade surface 1c before grinding and becomes thinner.

That is, since the tooth profile of the virtual gear represented by the new blade surface 1c is shifted from the tooth profile of the virtual gear represented by the original blade surface 1c, after grinding the blade surface 1c, the outer periphery 2 is
By moving the hob in the direction of the gear material by the amount that the number has gone down and creating it in the same manner as the grinding surface, it is possible to obtain a gear with the same tooth profile as before grinding.

As described in detail above, the present invention is actively rotated by a drive source, and rotates around a line passing through the support shaft 11 to which the hob material is attached and fixed, and the center of the spherical hob material attached to the support shaft 11. a gear mechanism 16 provided between the swivel base 13 and the drive source for controlling the rotational speed of the swivel base 13; and a base plate 19 provided on the base plate 19 so as to be able to be fixed to the base plate 19 and to be able to rotate around the rotation center of the swivel base 13 by releasing the fixation. A cutting tool mount 23 is provided, and a cutting tool for cutting the outer circumferential surface of the hob material is attached to the cutting tool mount 23, and the tool mount 23 is provided with a
A portion of the base plate 19 is engaged with a cam means provided between the base plate 19 and the base plate 19, which converts the reciprocating motion of the base plate 19 into a rotational motion and transmits the rotational motion to the blade mount 23, and is driven by the drive source. a cam 32 that is actively rotated to reciprocate the substrate 19;
By providing the gear mechanism 34 that is provided between the cam 32 and the drive source and for controlling the rotational speed of the cam 32, it has the above-mentioned advantages and can always be used even when the blade surface is ground. It exhibits an excellent effect in manufacturing a spherical hob that allows gears of the same shape and size to be created.

In the above embodiment, the case where the cutting edge groove 5 is parallel to the axis of the hob has been described, but if it is formed obliquely, it is necessary to change the indexing ratio by the second indexing mechanism 34.

That is, the indexing ratio η of a normal cylindrical hob.

As mentioned above, if the mechanical constant is F1 and the number of cutting grooves is N, then the indexing ratio η4 of a spherical hob in which the cutting edge grooves 5 are parallel to the axis is, as mentioned above, the horizontal rake angle to the cutting edge grooves 5. If β is attached, that is, the second
As shown in Figure 0, when the cutting edge groove 5 is inclined at an angle β with respect to the axis, further correction indexing is required.

The correction ratio for this is 77/2.
The intersection of the axis and the axis line is A, and the intersections of the two adjacent screw threads 6 and the axis line are B and C, respectively.

The intersection of the cutting groove 5 and the thread 6 is set to the pitch diameter of the E1 hob by π.
If the direction of arrangement of the hob blades 1 is right-handed and the angle β is positive, it is expressed as D, and when the direction of arrangement of the hob blades 1 is left-handed and the angle β is negative, it is expressed as , is expressed as .

Since it is expressed as Therefore, the above equation (2) is Therefore, the above formula (1) is Therefore, Cam index ratio η2 when the cutting groove is oblique but, Set it so that

[Brief explanation of drawings]

Figure 1 is a front view of the spherical hob, Figure 2 is its sectional view, and Figure 3 is a front view of the spherical hob.
The figure is a partial cross-sectional view showing the state of cutting an internal gear with a spherical hob.
Fig. 4 is a partial cross-sectional view showing the cutting state of a spur gear with a spherical hob, Fig. 5 is a plan view of the road body of a lathe embodying the present invention, and Fig. 6a is a perspective view of the blade mounting portion. 7 is a partial road body plan view showing a state in which the swivel table is rotated, FIG. 7 is a sectional view of the cutting part showing a state where the cutting tool is retracted by the cam, and FIG. 8 is a diagram showing a state in which the cutting tool is moved forward by the cam. Cross-sectional view of the cutting part, No. 9
The figure is a cross-sectional view of the cutting part showing the pin inserted into the pin hole, and Figure 10 is a diagram showing a comparison of the relationship between the back and forth movement of the board and the rotation of the mounting plate when the pin is inserted into the pin hole. Fig. 11 is a plan view of the cam, Fig. 12 is a cross-sectional view of the hob material finished into a spherical shape, Fig. 13 is a cross-sectional view showing the cutting state of the protrusion, and Fig. 14 is a side view of the side 2. Fig. 15 is a partial plan view showing a tooth groove type, half tooth groove type, and a normal cutting tool, respectively, and Fig. 16 is a perspective view and a side view of the hob blade, respectively. , a plan view, FIG. 17 is a front view of the road body showing the relationship between the amount of dislocation and the tooth thickness, FIG. 18 is a schematic side view showing the relationship between the depression amount of the outer periphery No. 2 and its angle, and FIG. 19 is a side view. No. 2 is a perspective view of the road body showing the relationship between the amount of dislocation and the angle, Figure 20 is a diagram showing the relationship between the slanted cutting edge groove and the indexing ratio, and Figure 21 is the rotation of the cam as the cutting tool rotates. FIG. 3 is a road body plan view showing the relationship between the position of the follower and the follower. Hob material 2/, support shaft 11, swivel base 13, base plate 19, cutter fixing plate 21, fixing member 22, cutter mount 23, bits 24 to 26, cam groove 31, cam 32, follower 33°

Claims (1)

[Scope of Claims] 1. A support shaft 11 that is actively rotated by a drive source and to which a hob material is attached and fixed; a gear mechanism 16 provided between the swivel base 13 and the one drive source for controlling the rotational speed of the swivel base 13; A base plate 19 is provided on the upper surface of the swivel base 13 so as to be movable back and forth, and a base plate 19 is provided on the base plate 19 so that it can be fixed to the base plate 19, and when the fixation is released, the swivel base 13 can be rotated. A cutter mount 23 that can rotate relative to the swivel base 13 about the center, and a cutting tool for cutting the outer peripheral surface of the hob material can be attached to the cutter mount 23. , the blade mount 2
A portion of the base plate 19 is engaged with a cam means provided between the base plate 19 and the base plate 19, which converts the reciprocating motion of the base plate 19 into a rotational motion and transmits the rotational motion to the blade mount 23, and is driven by the drive source. a cam 32 that is actively rotated to reciprocate the substrate 19;
A lathe for manufacturing a spherical hob for producing gears, characterized by comprising a gear mechanism 34 provided between the cam 32 and a drive source for controlling the rotational speed of the cam 32. 2. A lathe for manufacturing a spherical hob for gear generation according to claim 1, wherein the gear mechanisms 16 and 34 control the rotational speeds of the swivel base 13 and the cam 32 by exchanging their gears. . 3 The cutter mount 23 is a cutter that can be fixed on the base plate 19 and can be rotated relative to the swivel base 13 around the center of rotation of the swivel base 13 when the fixation is released. A lathe for manufacturing a spherical hob for gear generation according to claim 1, which is fixed to a fixed plate 21. 4. The cam means is constituted by a diagonal grooved cam 31 transparently provided in the base plate 19 and a guide pin 30 that projects from the blade fixing plate 21 and engages with the grooved cam 31. A lathe for manufacturing the spherical hob for gear generation according to item 3. 5. A patent claim in which the swivel 13 rotates by φ, where the rotation angle at which the swivel 13 rotates during one rotation of the support shaft 11 is φ, and Z is the number of teeth of the virtual gear drawn by the hob that is to be cut. A lathe for manufacturing the spherical hob for gear generation according to item 1. 6. The cam 32 rotates at an indexing ratio of per rotation of the support shaft 11, where N1 is the number of cutting grooves on the hob to be cut, and F is a mechanical constant.
A lathe for manufacturing the spherical hob for gear generation described in 2. 7 The cam 32 has an index ratio of 111 rotations of the support shaft, where the number of cutting grooves of the hob to be cut is N, the mechanical constant is F1, the horizontal rake angle of the cutting groove is β, and the advance angle of the hob is γ. Claim 5, which rotates at
A lathe for manufacturing the spherical hob for gear generation described in 2.