JPH0679527A - Divided type hob - Google Patents

Abstract

PURPOSE:To allow the spur gear of various modules to be machined by one set of divided type hobs by providing a plurality of blades along screw trace for one pitch, and thereby disposing both a first hob provided with the blades of more than one or two out of a plurality of the blades and a second hob provided with the rest of a plurality of the blades therein. CONSTITUTION:When the spur gear of a certain module is machined, a first hob 1 and a second hob 2 are mounted on rotation drive sections 8a and 8b in a state that the first and second hobs are parted as specified in such a way as to be of blade width corresponding to the module. Namely, the spur gear of a large module is machined, the first and second hobs are mounted on the rotation drive section 8a and 8b with a space extensively widened between a blade 52 provided for the first hob 1 and a blade 52 provided for the second hob 2. When the spur gear of a small module is machined, the hobs are mounted on the rotation drive sections 8a and 8b with the space narrowed between both of them 1 and 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split type hob used when cutting out a gear.

[0002]

2. Description of the Related Art A conventional hob for gear cutting is a type of milling cutter in which several vertical grooves are formed in a worm to form a cutting edge, and a second number is taken along the thread of the worm. When a spur gear is cut out using this hob, as shown in FIG. 13, the gear material 5 is made parallel to the axial direction C while rotating the hob 4 around its axis in the direction A shown in the figure. The tooth 5a can be cut out by moving it. However, hob 4
The gear material 5 rotates in the B direction at a rate of 1 pitch every 1 rotation. Then, the axial direction C and the axis H shown in FIG.
Is parallel to the plane of the paper.

When cutting a bevel gear using a conventional hob, as shown in FIG. 14, the gear material 60 is rotated while rotating the hob 61 around its axis in the direction A shown in the figure.
The tooth 60 by moving it parallel to its axial direction I.
a can be cut out. However, the gear material 60 rotates in the B direction at a rate of 1 pitch each time the hob 61 makes one rotation. The axis H shown in FIG. 14 is parallel to the paper surface, but the axial direction I is inclined with respect to the paper surface by the root cone angle of the bevel gear. The cutting blades are omitted in the hobs 4 and 61 shown in FIGS. 13 and 14.

[0004]

However, according to the conventional hob 4 shown in FIG. 13, in order to machine a spur gear of a certain module, a dedicated cutting edge corresponding to the module of the spur gear is provided. Need to use a hob. That is,
To machine multiple types of spur gears with different modules,
Each module must have its own hob. Therefore, since it is necessary to provide a large number of hobs, there is a problem that the cost is high and a large storage space is required on top of that.

According to the conventional hob 61 shown in FIG. 14, even when the bevel gear is machined in the same manner as the spur gear, a hob suitable for the tooth size of the bevel gear must be prepared in the same manner as described above. However, there is a problem that the cost of the hob is high and a large storage space is required.

When the bevel gear is cut out by the conventional hob 61, the teeth 6 of the bevel gear 60 are cut as shown in FIG. 15 (b).
The inner edge side of 0a (the side with small teeth) is the cutting edge 61 of the hob 61.
The outer end side (the side with the larger tooth) of the tooth 60a is carved by both the blade tip 61b and the tooth root 61c of the hob as shown in FIG. 15 (a). For this reason, the inner end side of the tooth 60a of the bevel gear 60 can be machined into a predetermined tooth profile, but the root end on the outer end side is cut down (undercut), which adversely affects the strength of the tooth. Occurs.

An object of the present invention is to provide a split type hob that solves the above problems.

[0008]

A split type hob of the first invention is provided with a plurality of blades along a thread of at least one pitch, and one or more blades of the plurality of blades are provided. It is characterized by comprising a first hob provided and a second hob provided with blades other than those provided on the first hob among the plurality of blades. In the split type hob of the second invention, a plurality of blades are provided along a thread of at least one pitch, and two blades are provided along the thread and pass through substantially the center of each of the blades. It is characterized by comprising a third hob and a fourth hob divided into

The split type hob according to the third invention is at least one.
A plurality of blades are provided along the thread for the pitch, and the plurality of blades are formed in the groove shape of the rack in the cross-sectional direction perpendicular to the thread direction, and at the same time for the thread. It is characterized in that it comprises a fifth hob and a sixth hob which are divided into two along a surface which passes along the substantially center of each blade formed in the groove shape of the rack. The split type hob of the fourth invention is the split type hob of the first invention, wherein a collar for positioning the first hob and the second hob at a predetermined interval is interposed between the two. The second hob and the collar are detachably fastened and coupled by a fastening device.

The split type hob of the fifth invention is the split type hob of the second invention, wherein a collar for positioning the third hob and the fourth hob at a predetermined interval is interposed therebetween. It is characterized in that the third hob, the fourth hob and the collar are detachably fastened and coupled by a fastening device. The split-type hob of the sixth invention is the split-type hob of the third invention, wherein a collar for positioning the fifth hob and the sixth hob at a predetermined interval is interposed between the two.
It is characterized in that the fifth hob, the sixth hob and the collar are detachably fastened and coupled by a fastening device.

[0011]

When the split type hob of the first invention is used to machine a spur gear, the central axes of the first hob and the second hob are aligned on the same straight line. Then, the corresponding blades of both hobs are made to face each other and are rotatably attached to the rotation drive section with a predetermined interval. Then, the directions of the thread of the first hob and the second hob and the direction of the tooth trace created by the gear material are made to coincide with each other. In this state, the first hob and the second hob are synchronously driven to rotate, and every time the first hob and the second hob make one rotation, the gear material is driven to rotate by one pitch about its central axis. Then, the first hob and the second hob are relatively fed from one end face side of the gear material toward the other end face side along the direction of the tooth trace to be created. As a result, the spur gear of the predetermined module can be cut out, as in the conventional hob. However, when a spur gear of a different module is machined, the first hob and the second hob are attached to the rotation drive section with a predetermined interval so that the blade width corresponds to the module. That is, when a large spur gear of a module is machined, the blades provided on the first hob and the blades provided on the second hob are attached to the rotation drive unit with a wide interval. When the small spur gear of the module is cut out, the space between the two is narrowed and the spur gear is attached to the rotation drive unit.

Next, a case where a bevel gear is cut out by using the split type hob of the first invention will be described. First, when cutting out the gear material of the bevel gear from the inner end face side (smaller teeth side) to the outer end face side (larger teeth side), the first hob and the second hob should have the same straight axis on each central axis. Match on the line.
Then, the corresponding blades of both hobs are made to face each other and are brought close to each other, and are attached to the rotation drive section. And
The directions of the screw threads of the first hob and the second hob are matched with the directions of the tooth traces created by the gear material. In this state, the first hob and the second hob are synchronously driven to rotate, and every time the first hob and the second hob make one rotation, the gear material is driven to rotate by one pitch about its central axis. Then, the first hob and the second hob are fed from the inner end surface side of the gear material toward the outer end surface side along the direction of the tooth trace created. At this time, the blades of the first hob and the second hob are moved in the directions in which they gradually separate from each other as they move in the feeding direction. As a result, it is possible to cut out a bevel gear having a predetermined tooth profile in which the module becomes larger from the inner end surface of the gear material toward the outer end surface thereof.

When the gear material of the bevel gear is machined from the outer end face side toward the inner end face side, the first hob and the second hob are used.
While sending the hob from the outer end surface side of the gear material to the inner end surface side,
The respective blades attached to the first hob and the second hob are moved in directions gradually approaching each other. In this way, it is possible to cut out a bevel gear having a predetermined tooth profile in which the module becomes smaller from the outer end surface to the inner end surface of the gear material.

Then, even if the third hob and the fourth hob or the fifth hob and the sixth hob are used in place of the first hob and the second hob, the spur gear and the bevel gear are machined in the same manner as described above. be able to. The split type hobs of the fourth, fifth and sixth inventions are hobs used only when the spur gear is machined.
According to this split type hob, since the collar is interposed between the first hob (the third hob, the fifth hob) and the second hob (the fourth hob, the sixth hob), they are tightened by the tightening device. Corresponding blade-to-blade spacings provided on the hobs can be positioned by the width of the collar.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A first embodiment of a split type hob according to the present invention is shown in FIG.
It will be described with reference to FIGS. However, this example
The split type hob is attached to the gear cutting device shown in FIG. 1 and the like to explain the creation of gears for a spur gear.

As shown in FIG. 1, a first hob 1 and a second hob 2 which constitute a split type hob for cutting out teeth of a spur gear.
Are rotatably held by the first hob holder 6 and the second hob holder 7, respectively. The first hob 1 is rotationally driven by the hob rotation driving unit 8a, and the second hob 2 is rotationally driven by the hob rotation driving unit 8b in the same direction and at the same rotation speed. Then, the gear material 13 is the gear material holding portion 9
It is rotatably held by the gear material rotary drive unit 10. Then, the first hob 1 and the second hob 2 respectively have the first and second hob holding portions 6,
7, the hob feed drive units 12a and 12b are held.
Is driven by the guides 11 and 23 in the direction along the central axis of the first hob 1 and the second hob 2 to move. Further, these guide portions 11 and 23 are provided on a sliding plate 58, and the sliding plate 58 is slidable in a direction perpendicular to the paper surface of FIG. 1 (direction of gear tooth groove). 37.

As shown in FIG. 4, the first hob 1 and the second hob 2 have a pitch of one pitch or a pitch slightly larger than one pitch with the two hobs 1 and 2 in close contact with each other. For example, eight rack blades 52 are provided on the thread of the. Then, the rack blades 5 provided on the first hob 1 and the rack blades 52 provided on the second hob 2 are alternately positioned so that the rack blades 5 are attached to the respective hobs 1 and 2.
There are four 2s provided. However, the number of rack blades 52 can be set to a number other than eight according to conditions such as cutting ability.

The first hob holding portion 6 comprises a first shaft 15 and a first body 16 as shown in FIG. First
The shaft 15 has a fitting portion 28 at the tip that fits into the inner hole 17 provided at the center of the first hob 1, and the first hob is provided at the flange-like projecting edge 18 provided slightly proximal to the fitting portion 28. 1 is fastened and fixed by a plurality of bolts 19. The base end side of the first shaft 15 is inserted into the insertion hole 20 of the first body 16 and is rotatably supported by the first body 16 via a bearing 21 (may be a metal bearing). Has been done. Then, the first main body 16 has a guide portion 11 which will be described later.
Is connected to the first movable base 24 of the.

The second hob holder 7 is equivalent to the first hob holder 6 and appears symmetrically in FIG. That is, as shown in FIG. 1, it comprises a second shaft 25 and a second body 26. The second shaft 25 and the first shaft 15 are
The respective central axes are provided on the same straight line. Then, the flange-shaped projecting edge 3 of the second shaft 25
The second hob 2 is fastened and fixed to 0 by a plurality of bolts 31. The base end side of the second shaft 25 is the bearing 3
It is rotatably supported by the second main body 26 via the unit 3. Then, the second main body 26 is coupled to the second movable base 34 of the guide portion 23 described later.

The hob rotation drive portion 8a is a servo motor, and is fastened and attached to the end surface of the first main body 16 by a bolt (not shown) as shown in FIG. The rotary shaft 35 of the motor 8 a is fitted into a hole opened at the end surface of the first shaft 15, and the rotary shaft 35 and the first shaft 15 are arranged so that the rotation of the rotary shaft 35 is transmitted to the first shaft 15. The shaft 15 is connected via a key (not shown). This motor 8
The a can rotate the first shaft 15 by rotationally driving the rotary shaft 35.

The hob rotation drive unit 8b is a hob rotation drive unit 8b.
It is a servo motor equivalent to a, the rotation shaft of which is coupled to the second shaft 25, and the second shaft 25 can be rotated by rotationally driving the rotation shaft. And
The hob rotation drive units 8a and 8b rotate the first hob 1 and the second hob 2 in the same direction and at the same angular velocity.
That is, the first and second hobs rotate synchronously.

As shown in FIG. 1, the gear material holding portion 9 holds a spur gear material 13 rotatably about its central axis, and the first hob 1 and the second hob 2 are gear materials. At the rotation position (cutting position) for creating 13
The gear material 13 is held so that the thread (blade) direction of the blades 52 of the first hob 1 and the second hob 2 and the direction of the tooth trace of the gear to be created match. The gear material holder 9 is not attached to the sliding plate 58, but is attached to another fixing base (not shown).

The gear material rotation drive unit 10 is an AC servomotor with a speed reducer and is electrically connected to the hob rotation drive units 8a and 8b. That is, as shown in FIG. 3, each time the hob rotation drive units 8a and 8b drive the first hob 1 and the second hob 2 and rotate the gear material 13 once in the E direction in FIG.
Are rotated by one pitch in the F direction in the figure.

The guide portions 11 and 23 are provided on the sliding plate 58 as shown in FIG. The guide unit 11 includes a first guide 39 and a first movable base 24, and the guide unit 2
3 comprises a second guide 40 and a second movable base 34. However, since the guide parts 11 and 23 are equivalent,
Only the guide unit 11 will be described. The first guide 39 of the guide portion 11 is fixedly attached to the sliding plate 58, and the first movable table 24 can slide on the first guide 39. The sliding directions of the first and second movable bases 24 and 34 are parallel to the central axes of the first and second hobs 1 and 2. Therefore, when the first and second movable bases 24 and 34 move in a direction away from each other, for example, the first and second hobs 1 and 2 move in a direction away from each other with the first and second movable bases 24 and 34. Moving.

Since the hob feed drive units 12a and 12b are equivalent, only the hob feed drive unit 12a will be described. The hob feed drive unit 12a includes a pulse motor 45 with a reduction gear and a ball screw 46 as shown in FIG. The pulse motor 45 is attached to the first movable base 24 in a state where the axial direction of the rotary shaft 59 is parallel to the central axis lines of the first and second hobs 1 and 2. A male screw 47 of the ball screw 46 is coupled to the rotary shaft 59 in parallel with the rotary shaft 59. The male screw 47 is screwed with the nut 48 of the ball screw 46, and the nut 48 is attached to the first guide 39. As a result, when the pulse motor 45 is rotationally driven, the male screw 47 is rotated accordingly, and the relative movement between the male screw 47 and the nut 48 moves the first movable base 24 to which the pulse motor 45 is attached. This allows the first hob 1 to be fed in the direction of the central axis of the first hob 1.

The sliding plate 58 is slidable along the base 37, and the sliding direction of the sliding plate 58 is parallel to the direction of the tooth gap created in the gear material 13. Although not shown in the figure, the sliding plate 58 is driven by a sliding plate feed drive unit (pulse motor).

Here, for example, as shown in FIG. 5, a case will be described in which an involute spur gear having 15 teeth, a pressure angle of 20 degrees and a module m ₁ = 12.5 is ground.
The blade depths of the first hob 1 and the second hob 2 are formed to have a higher dimension than the tooth depth of the spur gear to be created. Then, as shown in FIG. 5, each blade 52 of the first hob 1 and the second hob 2 is formed in a trapezoidal sectional shape, and the trapezoidal non-parallel left and right sides and the vertical line in the figure are The formed angle β is formed to be 20 degrees.
Then, the corresponding blades 5 of the first hob 1 and the second hob 2
Each blade 52 is formed so that the teeth of the spur gear can be milled with the two and 52 exactly overlapping in the thread direction.
That is, the total dimension of the blade thicknesses of the blades 52 on the reference pitch line corresponding to the spur gear of the module m ₁ = 12.5 is π.
m _1/2 (provided that, m ₁ = 12.5) formed. Then, as shown in FIG. 1, the first and second hobs formed as described above so that the direction of the blade line at the position where the gear material 13 is cut and the direction of the tooth trace of the gear material 13 are parallel to each other. 1 and 2 are attached to the first hob holder 6 and the second hob holder 7.

Next, as a procedure for cutting out the gear material 13 by using the first and second hobs 1 and 2, first, the first hob 1 and the second hob 2 are synchronously rotated by the motors 8a and 8b. Each time the first hob 1 and the second hob 2 rotate once, the servo motor 10 drives the gear material 13 to rotate one pitch about its central axis. Then, with the corresponding blades 52 of the first hob 1 and the second hob 2 being moved to a position where they overlap each other in the thread direction, the first hob 1 and the second hob 2 are rotated as shown in FIG. The material 13 is moved to a position on one end side. That is, the sliding plate 5 to which the first hob 1 and the second hob 2 are attached with the gear material holding portion 9 holding the gear material 13 fixed in a predetermined position.
8 is moved to bring the first hob 1 and the second hob 2 to the position on one end face side of the gear material 13 shown in FIG. Next, the sliding plate feed drive unit (not shown) is rotated in a predetermined direction, and the sliding plate 58 is moved rightward in FIG. To do. In this way, the involute spur gear can be generated by gear cutting.

Next, a gear cutting device adjusted so that a spur gear with a module m ₁ = 12.5 can be machined is a spur gear with a module m ₂ = 20 (the number of teeth is 15 and the pressure angle is 20 degrees). A procedure for adjusting so as to be able to cut out will be described. First, the hob feed drive units 12a and 12 shown in FIG.
The pulse motors 45, 45 of b are driven to move the first hob 1 and the second hob 2 away from each other. And
As shown in FIG. 6 (a), each blade 5 on the reference pitch line corresponding to the spur gear of module m ₂ = 20 to be created and corresponding
The total dimension of the tooth thicknesses of ₂ , 52 is πm 2/2 (however, m ₂
= 20), the pulse motors 45, 45 are stopped. That is, FIG. 2 shows that the first and second hobs 1, 2 can be machined so that the spur gear of the module m ₂ = 20 can be machined.
It is sectional drawing which shows the state which set.

When the spur gear with the module m ₂ = 20 is machined, the first hob 1 and the second hob 2 are driven with the motor 8a, as is the case with the spur gear with the module m ₁ = 12.5. 8b is driven to rotate, and the first hob 1 and the second hob
Every time the hob 2 makes one revolution, the gear material 13 is rotated by one pitch by the servo motor 10. And the first hob 1
And the second hob 2 is moved from one end side to the other end side of the gear material 13 as shown in FIG. In this way, the spur gear of module m ₂ = 20 can be generated by gear cutting. Although the same first and second hobs 1 and 2 are used to generate the gears for the spur gears of the modules 12.5 and 20, the same first and second hobs 1 and 2 are shown.
2 can be used to generate 12.5 <m (module) <20 spur gears. And the rack blade 52
By changing the shape of the first and second hobs 1 capable of generating spur gears of a module in a range different from the above,
2 can be obtained.

Next, a procedure for generating a gear by cutting a bevel gear using the above gear cutting device to which the first hob 1 and the second hob 2 are attached will be described with reference to FIGS. 7 and 8. It should be noted that this bevel gear has, for example, one tooth as shown in FIGS. 8 (a) and 8 (b).
5, an involute system with a pressure angle of 20 degrees, a small end side (hereinafter referred to as inner end side) tooth module m ₁ = 5, a large end side (hereinafter referred to as outer end side) module m ₂ = 10 And the gears. Here, when cutting the inner end side of the gear material 13 of the bevel gear, as shown in FIG. 8, each blade 5 on the reference pitch line corresponding to the tooth of the module m ₁ = 5.
The total size of the blade thickness of 2 πm _1/2 (provided that, m ₁ = 5)
When cutting the outer end side of the gear material 13, as shown in FIG. 8, the total dimension of the blade thickness of each blade 52 on the reference pitch line corresponding to the teeth of the module m ₂ = 10. There πm _2/2 (although, m ₂ = 10) is required to be. Therefore, first, as shown in FIG. 7, the gear material 13 is set so that the direction of the groove bottoms of the gear material 13 and the moving direction G of the first and second hobs 1 and 2 are parallel to each other. Attach to the holding part 9.

Next, the pulse motors 45, 45 of the hob feed drive units 12a, 12b are driven in a predetermined direction to correspond to the first hob 1 and the second hob 2 as shown on the inner end side in FIG. The first hob 1 and the second hob 2 are moved until the blades 52 are exactly overlapped in the thread direction. Then, the motors 8a and 8b are driven to synchronously rotate the first hob 1 and the second hob 2. At this time, the first hob 1 and the second hob
Each time the hob 2 makes one revolution, the gear material 13 drives the servomotor 10 so as to make one pitch rotation about its central axis. Then, in this state, the first hob 1 and the second hob 2 are moved to the position on the inner end side of the gear material 13 as shown in FIG. 7. That is, with the gear material holding portion 9 holding the gear material 13 fixed in a predetermined position, the first hob 1 and the second hob 1
Move the sliding plate 58 to which the hob 2 is attached,
The first hob 1 and the second hob 2 are brought to the inner end position of the gear material 13 shown in FIG. In this state, the inner end surface side of the gear material has begun to be ground, and this state is shown in FIG. 8 showing the inner end side of the gear material 13.

Next, in order to sequentially cut out the inner end surface side of the gear material 13 from the outer end surface side, the first and second hobs 1,
2 is moved in the G direction in FIG. 7 and the hob feed drive units 12a and 12b are driven to gradually widen the interval between the first and second hobs 1 and 2. That is, as shown in the diagram on the inner end side of FIG. 8, when the first hob 1 and the second hob 2 are at the inner end positions of the gear material 13, the blades 52 are overlapped with each other inside the gear material 13. Module m
Module 1 by carving out ₁ = 5 teeth and cutting the teeth while moving in a direction away from each other as the first hob 1 and the second hob 2 move to the outer end side along the tooth trace,
6 ... 7 ..., the large teeth of the module are gradually carved out, and the first hob 1 and the second hob 2 are moved to the outside as shown in the outer end side view of FIG. When they are moved to the end position, the teeth of the module m ₂ = 10 can be cut out by cutting the generated teeth while keeping a predetermined gap between them. In this way, the involute type bevel gear can be generated by gear cutting. The first hob 1 and the second hob 2 shown in FIG. 2 show a state equivalent to a state in which the outer end position of the gear material 13 of the bevel gear is generated by gear cutting. In addition, although the example which uses the 1st and 2nd hobs 1 and 2 to generate the bevel gears of 5 and 10 by the module of an inner end side and an outer end side was shown, this same 1st and 1st 2 hobs 1,
2 can be used in the same way as described above to allow the inner and outer modules to generate bevel gears, for example 6 and 9. Then, by changing the shape of the rack blade 52, it is possible to obtain the first and second hobs 1 and 2 capable of generating tooth cutting of the bevel gears of the inner end side and outer end side modules different from the above.

A second embodiment of the split type hob is shown in FIGS. 9 and 10.
Will be described with reference to. This split-type hob is for specifically cutting the spur gear. Therefore, the first hob 1 and the second hob 2 are fastened to each other, and the interval between the first hob 1 and the second hob 2 when cutting out the gear material is always maintained at a constant distance. That is, this split type hob is identical to the first embodiment in that it includes the first hob 1 and the second hob 2 which are the same as those in the first embodiment,
This is different from the first embodiment in that the gap between the hob 1 and the second hob 2 is positioned by a collar.

As shown in FIG. 9, this collar 60 is in the shape of a short cylinder, and one end face of the same figure abuts the inner side face of the first hob 1 and the other end face thereof is the inner side face of the second hob. Abutting. By using the collar 60 in this way, the first
The space between the hob 1 and the second hob 2 can be easily set to a desired size. And the first hob 1 and the second hob 2
The first hob 1 is cut by cutting out the gear material in the same manner as in the first embodiment with the distance between the first hob and the first dimension set to a predetermined value.
And the spur gear of the module corresponding to the total width of the blade width of the blade 52 of the second hob 2 can be generated.

When the spur gears of different modules are to be gear-cutting, a collar 63 having a width corresponding to the module is interposed between the first hob 1 and the second hob 2, and both hobs 1, Conclude 2. That is, the total size of the blade thicknesses of the blades 52, 52 on the reference pitch line corresponding to the spur gear of the module m to be created is πm / 2 with the collar 63 having a predetermined width interposed therebetween. .

Reference numeral 61 shown in FIG. 9 is a hob mounting shaft 61.
Both ends of the shaft 61 are rotatably supported by bearings 62. The hob mounting shaft 61 is driven to rotate by the hob rotation driving unit 8a as in the first embodiment. The first and second hobs 1 and 2 are attached to the hob attachment shaft 61 as follows. That is, as shown in FIG. 9, the hob mounting shaft 61 is passed through the first and second hobs 1 and 2, and both hobs 1 and 2 are connected to the projecting edge 18 and the washer 64.
Male screw 65 that is inserted into the hob mounting shaft 61
A nut 66 is screwed onto and tightened. Although not shown in the figure, the first hob 1 is fastened and fixed to the hob mounting shaft 61 with bolts. FIG. 10 shows each blade 5
Make sure that 2, 52 overlap exactly in the thread direction,
It is sectional drawing which shows the state which attached the 1st and 2nd hobs 1 and 2 through the collar of predetermined size.

However, in the first and second embodiments, as shown in FIG. 4, eight rack blades (four rack blades 52 are shown in the drawing are arranged on a thread having a pitch of 1 pitch or more than 1 pitch. A hob provided with a first hob 1 having four rack blades 52 out of eight rack blades 52.
And the second hob 2 having the remaining four rack blades 52 was used, but without using the first hob 1 and the second hob 2, as shown in FIG. A third hob formed by dividing a hob, in which eight rack blades are provided on a thread having a pitch larger than the pitch, into two along a thread passing through substantially the center of each rack blade. 53
And the fourth hob 54 can be used. In the third hob 53 and the fourth hob 54 divided in this way, FIG.
Blades 14, 14 ... Shown in (a) are provided. If the third and fourth hobs 53 and 54 shown in FIG. 11A are used to cut out a gear, the blade 14 of the third hob 53 and the blade 14 of the fourth hob 54 are spaced apart from each other. If it is present, the ridge is left uncut at the groove bottom of the gear. In order to prevent the ridges from being left uncut, as shown in FIG. 11B, the blades 14 of the third hob 53 and the blades 14 of the fourth hob 54 are provided in a jagged shape, and The notch 67 may be provided in the blade 14 and its vicinity. That is, gear cutting is performed in a state where the portion of the blade 14 facing each notch 67 where the notch 67 is not provided is fitted.

As another example of the first hob 1 and the second hob 2, as shown in FIG. 12, on a screw bar having one pitch or more pitches, a right angle to the screw bar direction. A fifth hob 56 in which a hob having a plurality of blades whose cross-sectional shape in the direction forms a groove 55 of a rack is divided into two along a thread of the hob, the surface passing through substantially the center of the groove 55 formed by each blade. Alternatively, the sixth hob 57 may be used. Figure 12 (a)
FIG. 7 is a diagram showing a state in which a gear having a large module is subjected to gear cutting. FIG.12 (b) is a figure which shows the state which generate | occur | produces a gear of a small module gear.

In the first embodiment, the gear material 13 of the bevel gear is machined from the inner end surface side toward the outer end surface side as shown in FIG. 7, but the gear material 13 is cut from the outer end surface side to the inner end surface side. It can also be carved out to the side. That is, as shown in the diagram on the outer end side of FIG. 8, the corresponding gears 52 of the first hob 1 and the second hob 2 are separated from each other by a predetermined distance, and the first hob 1 and the second hob 2 are attached to the gear material. 13 to the outer end position.
That is, the sliding plate 58 to which the first hob 1 and the second hob 2 are attached is moved with the gear material holding portion 9 holding the gear material 13 fixed at a predetermined position in the same manner as in the first embodiment. The first hob 1 and the second hob 2 into the gear material 13
Bring it to the outer edge position. Next, the first and second movable hoses 1 and 2 are moved in the direction opposite to G in FIG. 7 while moving the first and second movable bases 24 and 34 in a direction in which they gradually approach each other. That is, as shown in FIG. 8, the first hob 1 and the second hob 1
When the hob 2 is located at the outer end position of the gear material 13, the outer end side of the gear material 13 is cut off in a state of being isolated from each other, and the teeth of the module m ₂ = 10 are carved out. 2 As the hob 2 moves toward the inner end side along the tooth trace, the hobs 2 are moved toward each other to gradually cut out the small teeth of the module by cutting the generated teeth, and
As shown in FIG. 8, when the hob 1 and the second hob 2 are moved to the inner end position, the teeth of the module m ₁ = 5 can be carved out by cutting the teeth while the two are in contact with each other. it can. In this way, the involute type bevel gear similar to that of the first embodiment can be gear-cut.

Further, in the first and second embodiments, the split type hob having the plurality of blades 52 on the screw bar having one pitch or more pitches is used. However, for example, on the screw bar having two pitches or more. It may be a split type hob having a plurality of blades. However, when a hob having a plurality of screw bars is divided into two to form a pair of hobs, the blades of the two hobs come close to or apart from each other by a predetermined distance along the central axes of both hobs. In order to be able to do so, it is necessary to provide a gap between the blades of adjacent screw bars by the predetermined distance.

Further, in the first embodiment, the helical bevel gears are cut by generating teeth, but the helical bevel gears whose teeth are tangent to a certain circle can be cut by generating blades. That is,
The gear material of the helical bevel gear is attached to the gear material holding portion 9 at a position corresponding to the direction of the tooth trace of the helical bevel gear shown in FIG.

Although the servomotors are used for the hob rotation driving units 8a and 8b and the gear material rotation driving unit 10, other driving devices such as a pulse motor can be used instead. Further, although the pulse motors are used for the hob feed drive units 12a and 12b, other drive devices such as a servo motor can be used instead of the pulse motors.

[0044]

According to the split type hobs of the first to third inventions, when the spur gear of a certain module is machined, the first hob (third hob, The fifth hob) and the second hob (fourth hob, sixth hob) may be attached to the rotation drive section with a predetermined space therebetween to scrape the gear material, whereby one set of split hobs can be formed. Can be used to machine spur gears of multiple types of modules. Therefore, unlike the conventional case, it is not necessary to prepare a hob for each different module, and there is an effect that the cost of the hob can be reduced. Another advantage is that the hob has a small storage space.

According to the split type hob of the fourth to sixth inventions, the first hob (third hob, fifth hob) and the second hob (fourth hob, sixth hob) are provided with each other. The corresponding blade-to-blade spacing can be defined by the width of the collar. Therefore, by preparing in advance a plurality of types of collars with different widths so as to have a blade width according to the desired module, when cutting a spur gear of a certain module, the blade width according to the module and As described above, it suffices to interpose a corresponding collar between the first hob and the second hob and tighten the hobs, which has the effect of facilitating the attachment and adjustment of the hob to the rotation drive unit.

According to the split type hobs of the first to third inventions, when the bevel gear is machined, for example, the first hob (third hob, fifth hob) and the second hob (fourth hob, the fourth hob, 6
Since the hob) scrapes the inner end face side of the gear material in the state of approaching each other and gradually moves away from the approaching state of the first hob and the second hob, it scrapes toward the outer end face side. As shown in FIG. 15 (a), it is not necessary to cut down the bottom of the outer end face, and as shown in FIG. 15 (b), a bevel gear having the tooth profile on the inner end face formed into a tooth profile similar to the conventional one is carved out. There is an effect that can be.

In the second and fifth aspects of the invention, the third hob-side blade and the fourth hob-side blade shown in FIG. Therefore, it is necessary to make the total blade width of the blades of the third hob and the fourth hob smaller than the groove width. Therefore, when cutting a small tooth of a module (a tooth having a small tooth width), it may not be possible to give each blade a predetermined strength. However, this problem can be solved by using the first hob (fifth hob) and the second hob (sixth hob) of the first, third, fourth and sixth inventions. That is, each blade such as the first and second hobs can increase the blade width of one blade to the groove width. Accordingly, by using the first hob (fifth hob) and the second hob (sixth hob), spur gears and bevel gears having small modules can be machined.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a state where a split type hob according to a first embodiment of the present invention is attached to a gear cutting device and a spur gear of a small module is cut out.

FIG. 2 is a vertical cross-sectional view showing a state in which the split type hob of the first embodiment is attached to a gear cutting device and a spur gear of a large module is cut out.

FIG. 3 is a partial cross-sectional view showing the relationship between the mounting positions of the first hob and the second hob of the first embodiment and the gear material of the spur gear.

FIG. 4 is a front view of a first hob and a second hob of the same first embodiment.

FIG. 5 is a view showing a state in which a gear material of a spur gear having a small module is cut out by the first hob and the second hob of the first embodiment.

FIG. 6 is a view showing a state in which a gear material of a spur gear having a large module is cut out by the first hob and the second hob of the first embodiment.

FIG. 7 is a partial cross-sectional view showing the relationship between the mounting positions of the first hob and the second hob of the first embodiment and the gear material of the bevel gear.

FIG. 8 is a view showing a state in which the outer end position and the inner end position of the gear material of the bevel gear are cut out by the first hob and the second hob of the first embodiment.

FIG. 9 is a vertical cross-sectional view showing a state in which the split type hob according to the second embodiment of the present invention is attached to a gear cutting device and set so as to cut out a spur gear of a large module.

FIG. 10 is a longitudinal sectional view showing a state in which the split type hob of the second embodiment is attached to a gear cutting device and set so as to cut out a spur gear of a small module.

FIG. 11 (a) is a front view showing another embodiment of the split type hob according to the present invention, and FIG. 11 (b) is a partially enlarged view showing still another embodiment.

FIG. 12 (a) is a view showing a state in which a gear material of a spur gear having a large module is cut out by a fifth hob and a sixth hob of another embodiment of the present invention, and FIG. It is a figure which shows the state which cuts out the gear material of a gear.

FIG. 13 is a front view showing a state in which a spur gear is cut out by a conventional hob.

FIG. 14 is a front view showing a state in which a bevel gear is cut out by a conventional hob.

FIG. 15A is a diagram showing a state in which the outer end position of the gear material of the bevel gear is cut out by a conventional hob, and FIG. 15B is a diagram showing a state in which the inner end position of the gear material is cut out. is there.

[Explanation of symbols]

 1 1st hob 2 2nd hob 6 1st hob holding part 7 2nd hob holding part 8a Hob rotation drive part 8b Hob rotation drive part 9 Gear material holding part 10 Gear material rotation drive part 11 Guide part 12a Hob feed Drive part 12b Hob feed drive part 13 Gear material 14 Blade 23 Guide part 52 Rack blade 53 3rd hob 54 4th hob 55 Groove 56 5th hob 57 6th hob

Claims (6)

[Claims] 1. A first hob provided with a plurality of blades along at least one pitch of a thread, and one or more blades of the plurality of blades, and a first hob of the plurality of blades. A second hob provided with blades other than those provided on the 1 hob,
A split-type hob characterized by consisting of. 2. A plurality of blades are provided along a thread for at least one pitch, and the blade is divided into two along a surface passing along the thread and passing through substantially the center of each of the blades. A split type hob comprising three hobs and a fourth hob. 3. A plurality of blades are provided along at least one pitch of thread, and the plurality of blades are formed such that a cross-sectional shape in a direction perpendicular to the thread direction is a groove shape of a rack. And a fifth hob and a sixth hob, which are divided into two parts along the screw thread and at a plane passing through substantially the center of each blade formed in the groove shape of the rack. Type hob. 4. The split type hob according to claim 1,
A collar for positioning the first hob and the second hob at a predetermined interval is interposed between the two, and the first hob, the second hob and the collar are detachably fastened by a fastening device to be joined. Characteristic split type hob. 5. The split type hob according to claim 2,
The collar for positioning the third hob and the fourth hob at a predetermined interval is interposed between the two, and the third hob, the fourth hob and the collar are detachably tightened by a tightening device to be connected. Characteristic split type hob. 6. The split type hob according to claim 3,
A collar for positioning the fifth hob and the sixth hob at a predetermined interval is interposed between the two hobs, and the fifth hob, the sixth hob and the collar are detachably tightened by a tightening device to be connected. Characteristic split type hob.