JP2001353621A - Comb-like blade hob, and comb-like blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a comb-like blade capable of achieving gear cutting with high accuracy, and a hob having the comb-like blade. SOLUTION: When the relationship between the error (an) of the gear thickness of a reference blade and the absolute value (b) of the lower limit value (-b) of the tolerance (-b-0) of the gear thickness is (an)<=b, every cutting blade of the hob can be maintained within the tolerance of the gear thickness by realizing the negative correction of every cutting blade of the comb-like blade by correction value c (an<=c<=b). Gear cutting of the desired accuracy can be implemented only by assembling the corrected comb-like blade with a hob body, and gear cutting of higher accuracy can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hob used for gear cutting, and more particularly to a comb-type blade-type hob having a comb-type blade having a plurality of cutting edges formed thereon and being detachably used. The present invention relates to a comb blade.

[0002]

2. Description of the Related Art Hobbs, which are known as gear cutting tools, are those which directly form a cutting edge on a hob body, those which are brazed with a hard tip serving as a cutting edge on the hob body, or those having a large number of cutting edges. Various aspects have been devised, such as one in which a plurality of comb-shaped blades formed with are formed on the hob main body in a detachable manner, and those having an aspect matching the use conditions are selected and used. It has become. this house,
A hob (blade-type hob) in which a plurality of comb-shaped blades having a large number of cutting blades are detachably attached to the hob body is a blade having the damaged cutting blade when the cutting blade is damaged. Since it can be used immediately by simply exchanging it, it is increasingly used in recent production sites where strict productivity is required.

FIGS. 13 to 15 show a blade type hob 51.
1 shows a conventional example. The hob 51 shown in these figures
Is mounted on the outer periphery of the hob main body 53 in a state where a plurality of plate-like blades 52 are inclined by the advance angle θ (for example, see US Pat. No. 2,310,826 and US Pat. No. 2,567,167).

[0004]

Here, the cutting edge 54 of the hob 51, which is a rotary tool, is set so as to correspond to the advance angle θ.
It is spirally arranged on a rotating cylinder. Therefore, the gear cutting pitch of the hob 51 exists on the cylindrical surface.

However, the blade type hob 51 configured as shown in FIGS. 13 to 15 is formed such that a large number of substantially tooth-shaped cutting blades 54 are linearly located on a plate-like blade 52. Since the pitch line is linear, as shown in FIG. 6, the distance of the cutting edge 54 from the cutting edge 54 of the mounting reference point Po is shifted from the reference point Q of the theoretical pitch circle 25 to the position of the reference of the pitch line 24. Point P will be located.
Note that the theoretical pitch circle 25 refers to the pitch circle of the theoretical hob. Here, the theoretical hob is a hob in which the cutting edge is formed directly on the hob main body, and each part of the hob is formed without error with respect to a predetermined dimension. The rake angle of the theoretical hob is called a theoretical rake angle, and the circular pitch of the cutting edge of the theoretical hob is called a theoretical circular pitch. The cutting edge of the theoretical hob is referred to as a theoretical cutting edge (a cutting edge indicated by a dotted line in FIG. 7).

Although the theoretical pitch is an arc length represented by πm, the blade type hob 51 shown in FIG.
4 is linear, the cutting edge 5 of the blade 52
The pitch of No. 4 is shifted from the theoretical circular pitch.

Further, as shown in FIG. 8, the rake angle of the cutting edge at point P of the blade type hob becomes β, which is shifted from the theoretical rake angle α by (β−α).

As shown in FIG. 7, the deviation of the cutting edge of the blade type hob 51 with respect to the cutting edge of the theoretical hob is caused by errors in tooth thicknesses a1, a2 (a1) on the theoretical pitch circle 25.
+ A2 = an or ax). Then, the errors a1 and a2 of the tooth thickness appear as they are in the accuracy of the gear cutting. Therefore, the conventional blade-type hob 51 cannot perform high-precision gear cutting, and has been used as a gear cutting tool for rough machining.

In the case of performing high-precision gear cutting using the conventional blade-type hob 51, when the plate-like blade 52 is incorporated into the hob main body 53, each cutting blade 54 becomes a theoretical hob. All the cutting edges 54 of the blade 52 are individually ground so that no deviation occurs with respect to the cutting edge of the blade 52, so that the blade 52 forms a full-shaped cutting edge. However, the hob 51 in such an aspect has a problem that the machining allowance (grinding allowance) of the cutting blade 54 increases and the number of machining steps increases.

Accordingly, an object of the present invention is to enable high-precision gear cutting and to reduce the number of processing steps of the blade and, consequently, the number of manufacturing steps of the hob.

[0011]

According to the first aspect of the present invention, a comb-shaped blade having a large number of cutting blades for gear cutting formed in a straight line is tilted by an advance angle with respect to the axis of the hob main body. This is a comb blade type hob detachably mounted on the outer peripheral side of the hob body. The comb-type blade-type hob of the present invention is arranged such that each of the cutting edges is a comb-type blade formed so as to have a theoretical tooth thickness as a reference blade, and is linearly arranged on the outer peripheral side of the hob body. An error an between the tooth thickness of the cutting edge at the end of the reference blade and the theoretical tooth thickness of the cutting edge arranged on the pitch circle of the theoretical hob is calculated, and the error an of the tooth thickness is determined as the tooth thickness tolerance (−). When the absolute value of the lower limit of b to 0) is equal to or smaller than b (an ≦ b), the correction value c equal to or larger than an and equal to or smaller than b
(An ≦ c ≦ b), characterized in that the tooth thicknesses of all the cutting blades of the comb-shaped blade are negatively corrected.

The invention according to a second aspect of the present invention is the outer periphery of the hob main body in a state in which a comb-shaped blade formed with a large number of cutting teeth for cutting in a straight line is inclined by an advance angle with respect to the axis of the hob main body. This is a comb blade type hob detachably mounted on the side. And the comb blade type hob of the present invention is:
The comb blade shaped blade formed so that each of the cutting blades has a theoretical tooth thickness is used as a reference blade, and the tooth thickness of the cutting edge at the extreme end of the reference blade arranged linearly on the outer peripheral side of the hob body. An error an with the theoretical tooth thickness of the cutting blade arranged on the pitch circle of the theoretical hob is calculated, and this error an in the tooth thickness exceeds the absolute value b of the lower limit of the tooth thickness tolerance (-b to 0). (An>
b) In the case of the error between the tooth thickness of the cutting edge of the reference blade and the theoretical tooth thickness of the cutting edge arranged on the pitch circle of the theoretical hob, the largest error ax (ax ≤
b) is calculated, and a correction value d (ax ≦≦ b) equal to or more than ax and equal to or less than b
d ≦ b), the tooth thicknesses of all the cutting blades of the comb-shaped blade are corrected in a minus direction, and the cutting blades of the comb-shaped blade corresponding to the cutting edge that causes an error exceeding the error ax of the reference blade are individually set. It is characterized by being modified.

In a third aspect of the present invention, a plurality of cutting blades for gear cutting are formed in a straight line, and the cutting blade of the hob main body is inclined with respect to the axis of the hob main body by an advance angle. It is configured to be detachably mounted on the outer peripheral side.
The comb-shaped blade according to the present invention, wherein the comb-shaped blade formed such that each of the cutting edges has a theoretical tooth thickness is used as a reference blade, and the reference blade is linearly arranged on the outer peripheral side of the hob body. Error between the tooth thickness of the cutting edge at the extreme end and the theoretical tooth thickness of the cutting edge arranged on the pitch circle of the theoretical hob.
Is calculated, and the error an of the tooth thickness becomes the tooth thickness tolerance (−b to
0) when the absolute value of the lower limit value is equal to or smaller than b (an ≦ b), the tooth thickness of all the cutting edges of the comb-shaped blade is set to a correction value c (an ≦ c ≦ b) equal to or larger than an and equal to or smaller than b It is characterized by correcting for minus.

According to a fourth aspect of the present invention, there is provided a comb-shaped blade having a large number of cutting blades for gear cutting formed in a straight line, and being inclined at an angle of advance with respect to the axis of the hob body. It is configured to be detachably mounted on the outer peripheral side.
The comb-shaped blade according to the present invention, wherein the comb-shaped blade formed such that each of the cutting edges has a theoretical tooth thickness is used as a reference blade, and the reference blade is linearly arranged on the outer peripheral side of the hob body. Error between the tooth thickness of the cutting edge at the extreme end and the theoretical tooth thickness of the cutting edge arranged on the pitch circle of the theoretical hob.
Is calculated, and the error an of the tooth thickness becomes the tooth thickness tolerance (−b to
When the absolute value b of the lower limit of 0) is exceeded (an> b),
Among the errors between the tooth thickness of the cutting edge of the reference blade and the theoretical tooth thickness of the cutting edge arranged on the pitch circle of the theoretical hob, a maximum error ax (ax ≦ b) equal to or less than the lower limit value b is calculated. And
With the correction value d (ax ≦ d ≦ b) not less than ax and not more than b, the tooth thickness of all the cutting blades of the comb-shaped blade is negatively corrected, and the cutting edge which generates an error exceeding the error ax of the reference blade. It is characterized in that the cutting blades corresponding to are individually modified.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIGS. 1 to 5 are views showing a comb blade type hob (hereinafter abbreviated as a hob) 1 according to a first embodiment of the present invention. Among them, FIG. 1 is a front view of the hob 1 shown by cutting out a lower half from the center line, and FIG. 2 is a front view of the hob 1 shown without being cut out. FIG. 3 is a left side view of FIG. or,
FIG. 4 is a diagram showing a part of a cross section cut along the line AA of FIG. FIG. 5 is a partially enlarged view of FIG.

(Overall Structure of Hob) As shown in these figures, the hob 1 has a plurality of comb-shaped blades 3 arranged at equal intervals on the outer periphery of a hob body 2. The comb-shaped blade 3 is formed of a super-hard tool material such as a cemented carbide, cermet, ceramics, etc., and forms a cutting tooth 4 for gear cutting of a general shape on one long side of a substantially rectangular flat plate. It has a comb blade shape. The hob body 2 is substantially cylindrical,
A mounting hole 5 to be fitted to the machine-side arbor is formed at the center, and a key groove 6 for preventing rotation is formed in the mounting hole 5.

On the outer peripheral portion of the hob main body 2, a projection 7 having a substantially triangular cross section is formed in a spiral shape so as to correspond to the advance angle θ. The protrusions 7 are formed such that the pitch thereof matches the pitch of the cutting blade 4. Then, the projection 7 is divided by a groove 8 orthogonal to the advance angle θ, and is left as projections 7a arranged at equal intervals in the circumferential direction. A groove 10 serving as a stop groove at both ends is dug along the groove 8 by end milling, electric discharge machining, or the like, and the groove 10 constitutes a chip seat 11 together with the convex portion 7a. The tip seat 11 accommodates the comb blade 3. Since the front and back sides of the comb blade 3 have the same shape, the front and back sides are used as the cutting blades 4.

One end surface of each groove 10 is accurately formed so as to be along a direction of the advance angle θ, and serves as a reference surface 12 for positioning the comb blade 3. on the other hand,
The other end of each groove 10 is formed with a screw hole 14 penetrating from the hub surface 13 into the groove 10. And this screw hole 1
4 is screwed with a set screw 15.
Thus, the comb blade 3 is pressed against the reference surface 12 of the groove 10. As a result, the comb blade 3 is accurately positioned on the hob body 2.

A wedge hole 16 is formed at the front of the comb blade 3 in the rotation direction, and a holding piece 17 having a wedge-shaped cross section is inserted into the wedge hole 16. Presser piece 17 and hob body 2
Are formed with screw holes 18a and 18b having different arbitrarily, and by turning left and right screws 20 screwed into the screw holes 18a and 18b, the presser piece 17 rises and falls. As a result, the comb blade 3
Is the tip seat 1 due to the wedge-shaped cross section of the holding piece 17 that sinks.
1 and fixed. On the other hand, in a state in which the comb-shaped blade 3 is fastened and fixed to the tip seat 11 by the presser piece 17, the presser piece 17 is lifted up to release the tightened and fixed state of the comb-shaped blade 3 to the tip seat 11. The blade 3 can be removed from the tip seat 11.

Here, in order to accurately clamp the long comb-shaped blade 3 to the tip seat 11, two or more pressing pieces 17 are arranged for one comb-shaped blade 3. Is preferred. Because, if you try to clamp the comb blade 3 with one presser piece 17,
A turning moment easily acts on the comb-shaped blade 3, and the bottom surface 3 a at one end of the comb-shaped blade 3 has a tip seat 1.
This is because there is a risk of being clamped in a state in which it is lifted up from 1. The bottom surface 16a of the wedge hole 16 and the bottom surface 11a of the chip seat 11 are subjected to R chamfers 21 to 23, and
(See FIG. 5) so that stress concentration does not occur on the bottom surface 16a of the chip seat 11 and the bottom surface 11a of the chip seat 11.

(Correction of Cutting Edge of Comb Blade) As shown in FIG. 6C, the comb blade 3 has a plurality of cutting blades 4 arranged linearly, and the pitch of each of the cutting blades 4. The line 24 is a straight line and is perpendicular to the lead angle θ (axis 1
9 is attached to the hob main body 2 (inclined by the advance angle θ) (see FIG. 6A). Therefore, in the hob 1 of the present embodiment, the reference point P on the pitch line 24 of the end cutting edge 4 is shifted from the reference point Q on the pitch circle 25 of the theoretical cutting edge (FIG. 6B). reference). As shown in FIG. 8, the rake angle β of the comb blade 3 is shifted from the theoretical rake angle α by β-α. Further, the linear pitch L1 between the cutting blades 4 and 4 of the comb blade 3 and the theoretical pitch L2 in an arc shape (on the pitch circle 25) are shifted (L1-L).
2) occurs. The center cutting edge 4 of the comb blade 3
The point of intersection of the center line 26 and the pitch line 24 with the mounting reference point Po
The comb blade 3 is attached to the hob main body 2 such that the attachment reference point Po is located on the pitch circle 25 of the theoretical hob.

As described above, in the hob 1 using the comb-shaped blade 3 of the present embodiment, since the cutting edge 4 is shifted (three-dimensionally shifted) with respect to the theoretical hob, an error is caused in the tooth thickness t. a
1, a2 (see FIG. 7). Therefore, the errors a1 and a2 between the tooth thickness t of the cutting edge 4 of the hob 1 of the present embodiment and the tooth thickness t of the theoretical cutting edge of the theoretical hob are determined by the tooth thickness of a commonly used three-dimensional CAD program or the like. Determined by calculation means. This calculation result can be graphed as shown in FIG. In FIG. 9, the number of peaks indicates the number of the cutting blades 4 on one side from the mounting reference point Po, with the mounting reference point Po being 0. As shown in FIG. 9, the tooth thickness error increases as the number of peaks increases. Further, the calculation for obtaining the tooth thickness error is performed using a comb-shaped blade 3 formed so as to have a theoretical tooth thickness (a tooth thickness having no error) t as a reference blade.

The accuracy of the hob is determined according to the JIS standard (B4354).
And, for example, modules m: 2.
If the hob is over 5mm and 4mm or less and the grade is 2nd grade,
This is a tooth thickness error of −0.04 mm to 0 mm.

Therefore, the tooth thickness error is an, and the absolute value of the lower limit (-b) of the tooth thickness tolerance (-b to 0) is b (JIS).
If the relation between the tooth thickness error an and the absolute value b of the lower limit value of the tooth thickness tolerance is an ≦ b, the correction value c (an ≦ b) is set to the range from an to b. c ≦ b), so that the tooth thickness t of all the cutting blades 4 of the comb blade 3 is negatively corrected (see FIGS. 9 and 7).

For example, in FIG. 9, when the number of peaks is 10 and the hob class is the second class, the tooth thickness error an is 0.02 mm,
Since the absolute value b of the lower limit value (-b) of the tooth thickness tolerance (-b to 0) is 0.04 mm, it is 0.02 mm or more and 0.04 m.
If all the cutting edges 4 of the comb-shaped blade 3 are corrected in advance with a correction value c (an ≦ c ≦ b) of m or less, all the cutting edges 4 of the comb-shaped blade 3 incorporated in the hob main body 2 Is within the tooth thickness tolerance (−0.04 to 0 mm).

FIG. 9 shows the tooth thickness error when the cutting edge 4 of the comb blade 3 incorporated in the hob main body 2 is projected onto the cutting edge of the theoretical hob at a right angle to the rake face. In FIG. 9, a curve connecting white circles is an actual tooth thickness error curve. On the other hand, the curve connecting the black circles is the mounting reference point P
o -0.04mm (the accuracy of the hob is JIS2
7 is a tooth thickness error curve when the lower limit of the class is set.
That is, the curve connecting the black circles is obtained by shifting the tooth thickness error curve connecting the white circles downward by 0.04 mm.

Here, in FIG. 9, when a reference blade having 16 peaks is assumed, the peak at the blade end (16 peaks) is obtained.
In the position, the tooth thickness error an is about 0.055 mm, and the absolute value b of the lower limit of the tooth thickness tolerance is 0.04 mm.
(The accuracy of the hob is JIS class 2), then an> b. Therefore, the above-described tooth thickness correction cannot be applied as it is. Therefore, first, when the maximum value ax of the tooth thickness errors equal to or smaller than the absolute value b of the lower limit value of the tooth thickness tolerance is calculated, the tooth thickness error becomes 0.04 mm when the number of peaks is 14, and the boundary between the number of peaks 14 is obtained. Therefore, the correction method is divided.
That is, the comb-blade has a uniform shape of ax ≦
The numerical value d = 0.04 mm which satisfies the condition of d ≦ b is negatively corrected, and the cutting edge on the end side of the number of peaks 14 (the number of peaks 15,
The cutting edge 4 corresponding to 16 is individually ground so as to be within the tooth thickness tolerance.

As described above, in the present embodiment, the relationship between the tooth thickness error an of the reference blade and the absolute value (b) of the lower limit value (-b) of the tooth thickness tolerance (-b to 0) is an. When ≦ b, all the cutting edges 4 of the hob 1 are corrected by negatively correcting all the cutting edges 4 of the comb blade 3 with a correction value c (an ≦ c ≦ b) not less than an and not more than b. It can be kept within the tooth thickness tolerance. Therefore, according to the present embodiment,
Just by assembling the modified comb-shaped blade 3 to the hob main body 2, it is possible to perform the gear cutting with a desired accuracy, and it is possible to perform the gear cutting with a higher accuracy than the conventional example.

In the present embodiment, the relationship between the tooth thickness error an of the reference blade and the absolute value (b) of the lower limit value (-b) of the tooth thickness tolerance (-b to 0) is an> b. If there is a cutting edge of the following, calculate the maximum value ax of the tooth thickness error of b or less,
All the cutting edges 4 of the comb-shaped blade 3 are corrected with a numerical value d (ax ≦ d ≦ b) not less than ax and not more than b, and processing is individually performed only on the cutting edge 4 having a tooth thickness error of not less than b. For,
Compared to the case where all the cutting edges are individually processed to form a full-shaped cutting edge as in the conventional example, the processing allowance for the comb-shaped blade 3 can be reduced, and the number of processing steps for the comb-shaped blade 3 can be reduced. It can be significantly reduced. Therefore, the hob 1 of the present embodiment provided with such a comb blade 3 has a remarkably reduced number of manufacturing steps.

In this embodiment, FIG. 9 shows specific dimensions (tool diameter: φ110, pitch cylinder diameter: φ101.9).
75, radial rake: -10 °, end length: 1.25
m (m is a module), module: 3.25 mm, pressure angle: 25 °, lead angle (θ): 1.825 °, root length: 1 m (m is a module)) It is. Therefore, if the tool specifications of the hob are different, the tooth thickness error curve shown in FIG. 9 is also different, but a correction value (c, d) corresponding to the tooth thickness error curve is obtained, and based on the correction value. The cutting blade 4 of the comb blade 3 is corrected.

[Second Embodiment] FIG. 10 shows a main part of a hob 1 according to a second embodiment of the present invention. The hob 1 has rings 27, 28 attached to the outer periphery of both ends of the hob body 2, and a screw 30 for supporting one side surface 3 b of the comb blade 3 on one ring 27.
Is disposed on the other ring 28, and elastic biasing means 31 for supporting the other side surface 3c of the comb blade 3 is disposed. Here, the elastic urging means 31 is connected to the other ring 2.
8, a ball 34 and a spring 35 housed in a hole 33 of the screw 32, and the ball 34 is applied to the other side surface 3 c of the comb blade 3 by the spring force of the spring 35. It is designed to be pressed. The elastic biasing means 31 adjusts the elastic force of the spring 35 pressing the comb blade 3 by operating the screw 32.

The hob 1 according to the present embodiment having the above-described configuration is used.
By operating the screw 30 of one of the rings 27, the comb blade 3 can be slid leftward in FIG. 10 against the spring force of the elastic urging means 31, or the screw 3
By operating “0”, the comb blade 3 can be slid rightward in FIG. 10 by the spring force of the elastic urging means 31. As a result, since the position of the comb blade 3 can be adjusted in the hob axis direction (the direction indicated by the arrow 36), the accuracy of the position of the cutting blade 4 in the hob axis direction 36 can be improved.
Combined with the effect of improving the cutting edge accuracy of the comb blade 3 according to the first embodiment, the cutting edge accuracy of the hob 1 can be further improved.

[Third Embodiment] FIGS. 11 to 12 show
9 shows a main part of a hob 1 according to a third embodiment of the present invention. In these figures, the hob 1 is formed so that both side surfaces 3b and 3c of the comb blade 3 are formed at an acute angle with respect to the bottom surface 3a, and one side 3b of the inclined side surfaces 3b and 3c is pressed by a wedge 37. The other side 3c of the inclined side surfaces 3b, 3c is pressed by the elastic urging means 31.

Here, the wedge 37 is accommodated in a wedge hole 38 formed in the hob main body 2, and is moved up and down in the wedge hole 38 by operating the left and right screws 40. When the right and left screws 40 are operated and the wedge 37 is lowered, the comb blade 3 moves leftward in the figure against the spring force of the elastic urging means 31. On the other hand, the left and right screws 40 are operated to
7 rises, the comb-shaped blade 3
1 to move rightward in the figure.

According to the present embodiment having such a structure, the same effects as those of the second embodiment can be obtained, and the both side surfaces 3b, 3 of the comb blade 3 can be obtained.
Since c is an inclined surface, the comb-shaped blade 3 is constantly pressed against the bottom surface 11a of the tip seat 11 by the component force of the force acting on the inclined surface, and the comb-shaped blade 3 is
Accordingly, the position of the comb blade 3 in the hob axis direction 36 can be adjusted more accurately and easily. In this regard, in the aspect of the second embodiment, when adjusting the position of the comb blade 3 in the hob axis direction 36, the operator presses the comb blade 3 toward the bottom surface 11a of the tip seat 11. Therefore, the burden on the worker is increased as compared with the present embodiment.

[0037]

As described above, according to the present invention, the lower limit (-b) of the tooth thickness error an of the reference blade and the tooth thickness tolerance (-b to 0).
When the relationship between b) and the absolute value (b) is an ≦ b, a
By correcting all the cutting edges of the comb-shaped blade with a correction value c (an ≦ c ≦ b) of n or more and b or less, all the cutting edges of the hob can be kept within the tooth thickness tolerance. . Therefore, according to the present invention, it is possible to perform the gear cutting with a desired accuracy only by assembling the corrected comb-shaped blade to the hob main body, and it is possible to perform the gear cutting with higher precision than the conventional example.

In addition, the present invention provides a tooth thickness error a of the reference blade.
When there is a cutting edge in which the relationship between n and the absolute value (b) of the lower limit (-b) of the tooth thickness tolerance (-b to 0) is an> b,
The maximum value ax of the tooth thickness error of b or less is calculated, and all the cutting edges of the comb-shaped blade are corrected by a numerical value d (ax ≦ d ≦ b) of ax or more and b or less. In order to individually process only the cutting edge that was above, compared to the case where all the cutting edges are individually processed and formed into a full-shaped cutting edge as in the conventional example, the processing allowance of the comb blade is reduced. And the number of processing steps of the comb blade can be remarkably reduced.
Therefore, the hob of the present invention including such a comb blade can significantly reduce the number of manufacturing steps.

[Brief description of the drawings]

FIG. 1 is a front view of a comb-type blade type hob 1 in which a lower half is cut away from a center line.

FIG. 2 is a front view of the comb-type blade type hob 1 shown without notching.

FIG. 3 is a left side view of FIG. 2;

FIG. 4 is a diagram showing a part of a cross section cut along the line AA of FIG. 1;

FIG. 5 is a partially enlarged view of FIG. 4;

FIG. 6 is a diagram showing a cause of occurrence of a tooth thickness error. FIG.
FIG. 6A is a front view showing an attached state of a comb blade, and FIG. 6B is a right side view of FIG.
(C) It is a front view of a comb blade.

FIG. 7 is a diagram showing an error between the tooth thickness of the cutting edge of the reference blade and the tooth thickness of the cutting edge of the theoretical hob.

FIG. 8 is a view showing a deviation of a rake angle of a cutting blade of a reference blade.

FIG. 9 is a diagram showing a tooth thickness error curve.

FIG. 10 is a cross-sectional view of a main part on the front side of a comb blade type hob according to a second embodiment of the present invention.

FIG. 11 is a cross-sectional view of a main part on the front side of a comb blade type hob according to a third embodiment of the present invention.

FIG. 12 is a plan view of FIG. 11;

FIG. 13 is a side view showing a conventional hob with a part cut away.

FIG. 14 is a sectional view taken along line BB of FIG. 13;

FIG. 15 is a plan view showing a part of a conventional hob.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hob, 2 ... Hob main body, 3 ... Comb blade, 4 ... Cutting blade, 19 ... Axis line, 25 ... Pitch circle, θ
…… Lead angle, t …… Tooth thickness

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Shinshiro 580, Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Inside Solid Square Toshiba Tungaloy Co., Ltd. Solid Square Toshiba Tungaloy Co., Ltd. (72) Inventor Masaki Nobuhara 23 Tsutsuzucho, Komatsu-shi, Ishikawa Pref. Komatsu Ltd. Awazu Plant F-term (reference)

Claims (4)

[Claims] 1. A comb-shaped blade having a number of cutting blades for gear cutting formed in a straight line is detachably mounted on the outer peripheral side of the hob main body in a state of being inclined by an advance angle with respect to the axis of the hob main body. In the comb-type blade-type hob, the comb-shaped blade formed so that each of the cutting edges has a theoretical tooth thickness is used as a reference blade, and the reference blade is linearly arranged on the outer peripheral side of the hob body. An error an between the tooth thickness of the cutting edge at the extreme end and the theoretical tooth thickness of the cutting blade arranged on the pitch circle of the theoretical hob is calculated, and the error an of the tooth thickness is determined as the tooth thickness tolerance (−b to 0). Or less than the absolute value b of the lower limit of () (an ≦ b)
, The correction value c (an ≦ c ≦
b) A comb-type blade-type hob, wherein the tooth thickness of all the cutting edges of the comb-type blade is minus-corrected. 2. A comb-shaped blade having a number of cutting blades for gear cutting formed in a straight line is detachably mounted on the outer peripheral side of the hob main body in a state of being inclined by an advance angle with respect to the axis of the hob main body. In the comb-type blade-type hob, the comb-shaped blade formed so that each of the cutting edges has a theoretical tooth thickness is used as a reference blade, and the reference blade is linearly arranged on the outer peripheral side of the hob body. An error an between the tooth thickness of the cutting edge at the extreme end and the theoretical tooth thickness of the cutting blade arranged on the pitch circle of the theoretical hob is calculated, and the error an of the tooth thickness is determined as the tooth thickness tolerance (−b to 0). ) Exceeds the absolute value b of the lower limit (an>).
b) In the case of the error between the tooth thickness of the cutting edge of the reference blade and the theoretical tooth thickness of the cutting edge arranged on the pitch circle of the theoretical hob, the largest error ax (ax ≤
b) is calculated, and a correction value d (ax ≦≦ b) equal to or more than ax and equal to or less than b
d ≦ b), the tooth thicknesses of all the cutting blades of the comb-shaped blade are corrected in a minus direction, and the cutting blades of the comb-shaped blade corresponding to the cutting edge that causes an error exceeding the error ax of the reference blade are individually set. A comb-type blade type hob characterized by being modified into a shape. 3. A plurality of cutting blades for gear cutting are formed in a straight line, and the comb blade is detachably mounted on the outer peripheral side of the hob main body in a state where the cutting blade is inclined by an advance angle with respect to the axis of the hob main body. In the shape-shaped blade, a comb-shaped blade formed so that each of the cutting edges has a theoretical tooth thickness is used as a reference blade, and a cutting edge at an endmost portion of the reference blade linearly arranged on the outer peripheral side of the hob body. Is calculated from the theoretical tooth thickness of the cutting blades arranged on the pitch circle of the theoretical hob, and the error an of the tooth thickness is the absolute value of the lower limit of the tooth thickness tolerance (-b to 0). Value b or less (an ≦ b)
, The correction value c (an ≦ c ≦
b) A comb-shaped blade, wherein the tooth thickness of all the cutting edges of the comb-shaped blade is corrected in a minus direction. 4. A plurality of cutting blades for gear cutting are formed in a straight line, and the comb blade is detachably mounted on the outer peripheral side of the hob main body in a state of being inclined by an advance angle with respect to the axis of the hob main body. In the shape-shaped blade, a comb-shaped blade formed so that each of the cutting edges has a theoretical tooth thickness is used as a reference blade, and a cutting edge at an endmost portion of the reference blade linearly arranged on the outer peripheral side of the hob body. Is calculated from the theoretical tooth thickness of the cutting blades arranged on the pitch circle of the theoretical hob, and the error an of the tooth thickness is the absolute value of the lower limit of the tooth thickness tolerance (-b to 0). Exceeds the value b (an>
b) In the case of the error between the tooth thickness of the cutting edge of the reference blade and the theoretical tooth thickness of the cutting edge arranged on the pitch circle of the theoretical hob, the largest error ax (ax ≤
b) is calculated, and a correction value d (ax ≦≦ b) equal to or more than ax and equal to or less than b
d ≦ b) by negatively correcting the tooth thicknesses of all the cutting blades of the comb-shaped blade, and individually correcting the cutting blades corresponding to the cutting blades having an error exceeding the error ax of the reference blade. A comb-shaped blade.