JP6959117B2 - Machining tools, machining equipment and machining methods - Google Patents

Description

The present invention relates to a processing tool for processing a pulley of a belt-type continuously variable transmission (CVT), a processing device using the same, and a processing method using the same.

The pulley of a belt-type continuously variable transmission (CVT) is a rotating body that requires high hardness and surface processing accuracy. When processing such a pulley, the work that has been raw processed by forging or the like is heat-treated. , Machining with a lathe, etc. At the time of this machining, the work is centered and mounted on the chuck, and cutting and surface grinding are performed while rotating the work.

For example, during the above machining, while rotating the centered workpiece, the sheave surface is first cut by hard turning, then the outer peripheral surface of the shaft portion of the pulley is cut by hard turning, and then the sheave is machined. The surface or the like is ground using a grindstone or the like.

On the other hand, while the above-mentioned hard turning process is point cutting by the cutting blade of the point-shaped CBN insert, hard skiving that can perform cutting over a wide area and with less unevenness by using the cutting width of the wide CBN insert. Machining (also called lead-free machining) has been developed, and according to this, a smooth machined surface can be obtained even if the feed rate is increased (Patent Document 1).

In both hard turning and lead-free machining, the CBN insert that cuts the sheave surface is usually fixed to a dedicated holder, and the CBN insert that cuts the outer peripheral surface of the shaft of the pulley is used as a dedicated holder. It is fixed, each holder is attached to the holder bracket, and this holder bracket is attached to the turret.

JP-A-2017-196692

By the way, when cutting a workpiece with high surface hardness with high precision, if the main component force and feed component force at the time of cutting are high, the machined surface will escape due to the deflection and deformation of the turret and tool holder. It is easy to cause problems such as chattering and sagging of the machine, which makes the dimensions not follow and the machining diameter becomes unstable, and it is required to suppress the occurrence of these problems.

As described above, the machining tool has a multi-part structure consisting of four parts: turret ⇔ holder bracket ⇔ holder ⇔ CBN insert, and the rigidity of each part is reduced and bending occurs. Therefore, it is considered that deformation is likely to occur as a whole.
In the case of hard skiving, since the cutting is performed by line contact, the main component force and the feed component force at the time of cutting become extremely high, and the above-mentioned defects become more remarkable.

Further, conventionally, since different holders are used for the CBN insert for processing the sheave surface and the CBN insert for processing the outer peripheral surface of the shaft portion as described above, turret rotation is required when switching tools.
Therefore, in the case of lead-free machining in which the machining time can be shortened, the turret turning time is a major issue in improving the production efficiency.

The present invention was devised in view of such a problem, and in the machining of a pulley for a CVT which requires high hardness and surface machining accuracy, a smooth machined surface having a desired shape while improving productivity is required. It is an object of the present invention to provide a machining tool, a machining apparatus using the machining tool, and a machining method using the machining tool.

(1) In order to achieve the above object, the machining tool of the present invention is a machining tool for machining a work as a stepless speed change pulley having a sheave surface and an outer peripheral surface of a shaft portion, and the shaft. The first cutting blade, which is a CBN chip that cuts the outer peripheral surface of the portion , the second cutting blade, which is a CBN chip that cuts the sheave surface, the first cutting blade, and the second cutting blade are attached to the turret. and a holder that will be directly fixed, the holder includes a first opposing surface facing the direction of the shaft portion outer circumferential surface during cutting, and a second opposing surface facing the direction of the sheave surface during cutting, the first opposing surface A corner portion where and the second facing surface intersect, a first mounting portion arranged at a position adjacent to the corner portion on the first facing surface and attaching the first cutting blade, and the said on the second facing surface. It is characterized by having a second mounting portion which is arranged at a position adjacent to the corner portion and which mounts the second cutting blade.
(2) the holder is formed into a block shape, the a mounting base that is attached to the tool rest located on the side of the workpiece, to an edge of the mounting base portion protrudes said first from said mounting base A cutting blade mounting portion having a facing surface, the second facing surface, and the corner portion is provided, and the other edge side of the mounting base portion, which is opposite to the second facing surface of the cutting blade mounting portion, is It is preferable that it is partially scraped off.
(3) It is preferable that a reinforcing wall portion for applying the back component force of the second cutting blade is formed behind the second facing surface of the cutting blade mounting portion.
(4) It is preferable that the first mounting portion and the second mounting portion are arranged at a predetermined interval along the direction in which the corner portion extends.
(5) The first cutting blade and the second cutting blade are preferably cutting blades for hard skiving that perform wide cutting.

(6) The processing apparatus of the present invention includes a tool post to which the machining tool according to any one of (1) to (5) is attached, and a work mount to which the workpiece is aligned and attached. It is characterized by having.

(7) The processing method of the present invention is a processing method for processing the work using the processing apparatus described in (6), and is a processing method for processing the work centered on the work mounting base. The outer circumference of the shaft portion is moved by the first cutting blade while moving the holder in the Z-axis direction, which is the axial direction of the work mounting base, from the side of the outer peripheral surface of the shaft portion that is separated from the sheave surface to the side that approaches the sheath surface. A first cutting step of cutting a surface, an intermediate step of moving the holder in the Y-axis direction orthogonal to the Z-axis direction so that the second cutting blade reaches the outer peripheral edge of the sheave surface, and then an intermediate step. A second cutting step of cutting the sheave surface with the second cutting blade while moving the holder in the Y-axis direction from the outer peripheral edge of the sheave surface to the inner peripheral side of the work. It is characterized by having.

According to the present invention, the first cutting blade that cuts the outer peripheral surface of the shaft portion of the stepless speed change pulley and the second cutting blade that cuts the sheave surface are both attached to the same holder, so that the processing tool is configured. The number of parts can be suppressed, the rigidity of the tool can be ensured, and the occurrence of bending can be suppressed. Therefore, the cutting accuracy can be improved. In addition, a cutting blade for hard skiving, which has extremely high main component force and feed component force during cutting, is applied to the first cutting blade and the second cutting blade to improve productivity and smooth the desired shape. A machined surface can be obtained.

It is a front view which shows the main part of the processing apparatus (turret lathe) which concerns on one Embodiment of this invention. It is a perspective view which shows the main part of the processing tool which concerns on one Embodiment of this invention. It is a front view of the main part of the processing apparatus which shows the movement of the holder at the time of cutting by the processing tool which concerns on one Embodiment of this invention. It is a front view of the work (pulley) which shows the movement of the cutting blade at the time of cutting by the processing tool which concerns on one Embodiment of this invention. It is a top view of the work (pulley) which shows the movement of the cutting blade at the time of cutting by the processing tool which concerns on one Embodiment of this invention. It is a perspective view of the work (pulley) which shows the movement of the cutting blade at the time of cutting by the processing tool which concerns on one Embodiment of this invention.

Hereinafter, embodiments of a machining tool, a machining apparatus, and a machining method according to the present invention will be described with reference to the drawings. It should be noted that the embodiments shown below are merely examples, and there is no intention of excluding the application of various modifications and techniques not specified in the following embodiments. Such an embodiment can be partially used, partially modified, or replaced with another mechanism or device having the same function.

[Configuration of processing equipment]
First, the processing apparatus according to the embodiment will be described.
As shown in FIG. 1, this processing device is a turret lathe having a swivel turret, so that the clamp device 11 and the tail center (pushing center) 12 face each other on the Z axis (spindle) of the lathe. It is provided with a work mounting base 10 that is arranged. Further, a swivel turret 14 having a turret 13 (here, only a part of the turret 13 is shown) is arranged on the side of the Z-axis (Y-axis direction).

The work 20W as a continuously variable transmission pulley is a combination of a fixed sheave 21 having a sheave surface 21F to be machined and a pulley shaft (shaft portion) 22 having a shaft portion outer peripheral surface 22F to be machined. .. The pulley shaft 22 has a first shaft portion 23 that projects long toward the sheave surface 21F side of the fixed sheave 21, and a second shaft portion 24 that projects shortly toward the sheave surface 21F with respect to the fixed sheave 21. The outer peripheral surface 22F of the portion is located on the first shaft portion 23 on which a movable pulley (not shown) slides in the axial direction.

In the work 20W, the tip portion 24a of the second shaft portion 24 is clamped by the clamping device 11, the tip portion 23a of the first shaft portion 23 is locked to the tail center 12, and the axis of the work 20W is the Z axis of the lathe. It is arranged so as to coincide with and is fixed to the work mounting base 10.
The work mounting base 10 rotationally drives the fixed work 20W around the Z axis. While moving the tool post 13 in the Z-axis direction of the lathe and in the direction of approaching and separating from the Z-axis of the lathe (Y-axis direction), the cutting blade attached to the tool post 13 is rotated. It is designed to be cut in contact with the.

[Machining tool]
As shown in FIGS. 1 and 2, the machining tool 30 has a holder 31 fixed to the tool post 13, and a first cutting blade 32 and a second cutting blade 33 fixed to the holder 31. .. The first cutting blade 32 is a cutting blade that cuts the outer peripheral surface 22F of the shaft portion, and the second cutting blade 33 is a cutting blade that cuts the sheave surface 21F.

The holder 31 is made of steel and is formed in a block shape (a shape in which a part of a rectangular parallelepiped block is cut off), and is mounted on the tool post 13 and protrudes from one edge side of the mounting base 311. It has a cutting blade mounting portion 312. The cutting blade mounting portion 312 has a first facing surface 313 facing the direction of the outer peripheral surface 22F of the shaft portion during cutting, a second facing surface 314 facing the direction of the sheave surface 21F during cutting, and a first facing surface 313 and a second facing surface. It has a corner portion 315 at which the surface 314 intersects.

A first mounting portion 320 for mounting the first cutting blade 32 is arranged at a position adjacent to the corner portion 315 on the first facing surface 313, and a second mounting portion 320 is arranged at a position adjacent to the corner portion 315 on the second facing surface 314. A second mounting portion arrangement 330 for mounting the cutting blade 33 is arranged.

Further, the other edge side of the mounting base portion 311 and the side opposite to the second facing surface 314 of the cutting blade mounting portion 312 is reduced in weight by the lightening portion 316 that has been partially scraped off.
However, the cutting edge portion 316 is not provided on the opposite side (behind) of the second facing surface 314 of the cutting blade mounting portion 312, and the reinforcing meat portion 317 for applying the back component force by the second cutting blade 33 is formed. Has been done.

The first mounting portion 320 (first cutting blade 32) and the second mounting portion 330 (second cutting blade 33) have a corner portion 315 extending at the intersection of the first facing surface 313 and the second facing surface 314. They are arranged at predetermined intervals L (for example, 25 mm) along the direction. Further, here, the first mounting portion 320 is arranged on one side (left side in FIG. 2) and the second mounting portion 320 on the other side (right side in FIG. 2) with respect to the intermediate portion 318 in the direction in which the corner portion 315 extends. The mounting portion 330 is arranged.

Neither the first facing surface 313 nor the second facing surface 314 is a simple flat surface, and in the first facing surface 313, the region in which the first mounting portion 320 is formed is separated from the mounting base portion 311 (during cutting). It protrudes most in the direction of the outer peripheral surface 22F of the shaft portion), and in the second facing surface 314, the region where the second mounting portion 330 is formed protrudes most in the direction of the sheave surface 21F at the time of cutting.

Both the first cutting blade 32 and the second cutting blade 33 are cutting blades for hard skiving that perform wide cutting, and are composed of a rectangular CBN chip (CBN: Cubic boron nitride) having a thickness. .. Further, the first cutting blade 32 and the second cutting blade 33 are fixed in the grooves of the first mounting portion 320 and the second mounting portion 330 so that the cutting edges 32a and 33a are inclined and detachably attached by bolts. Further, at the tips of the cutting edges 32a and 33a, hole-shaped chip pockets 321 and 331 for receiving chips are formed.

Further, the holder 31 is provided with a bolt hole 319 from the side of the first facing surface 313 to the bottom surface portion of the mounting base portion 311 that directly contacts the tool post 13. A total of four bolt holes 319 are provided, and the bolt holes 319 are directly fixed to the tool post 13 by tightening four points. In FIG. 2, the bolt hole 319 of the wall cutting portion 316 is hidden behind the cutting blade mounting portion 312.

[Processing method]
Next, a machining method using a machining apparatus equipped with the machining tool 30 will be described.
First, the work 20W is aligned and attached to the work mounting base 10. Then, while rotating the work 20W, first, as shown by arrow a1 in FIG. 3, the outer peripheral surface 22F of the shaft portion is moved from the side separated from the sheave surface 21F to the side approaching the sheave surface 21F in the axial direction of the work mounting base 10. The outer peripheral surface 22F of the shaft portion is cut by the first cutting blade 32 while moving the holder 31 in a certain Z-axis direction (first cutting step).

After that, as shown by the arrow a2 in FIG. 3, the holder 31 is moved in the Y-axis direction and the Z-axis direction so that the second cutting blade 33 reaches the outer peripheral edge of the sheave surface 21F (intermediate step).
After that, as shown by the arrow a3 in FIG. 3, the sheave surface 21F is moved by the second cutting blade 33 from the outer peripheral edge of the sheave surface 21F to the inner peripheral side in the Y-axis direction with respect to the work 20W. (Second cutting process).

[Action and effect]
Since the machining tool, the machining device, and the machining method according to the present embodiment are configured as described above, the machining tool has three parts of turret ⇔ holder ⇔ cutting blades 32, 33 (CBN insert) and the number of parts is reduced. It is possible to suppress a decrease in rigidity at the mating portion of the parts, and it is possible to suppress the occurrence of bending.

By suppressing the occurrence of bending, the cutting accuracy can be improved. Further, a cutting blade for hard skiving processing, which has extremely high main component force and feed component force during cutting, is applied to the first cutting blade 32 and the second cutting blade 33 to improve productivity and a desired shape. A smooth machined surface can be obtained.

Further, since the other edge side of the mounting base portion 311 is lightened by the lightening portion 316 that has been partially scraped off, the weight of the holder 31 can be reduced.
Moreover, while the weight is reduced, the cutting blade mounting portion 312 is not provided with the meat cutting portion 316 on the opposite side (behind) to the second facing surface 314, and the reinforcing meat portion 317 is formed, so that the second cutting is performed. The back component force of the blade 33 can be secured.

In addition, the effect of the movement of the cutting blades 32 and 33 during machining can also be obtained.
4 to 6 are views showing the movements of the first cutting blade 32 and the second cutting blade 33 during this cutting process, FIG. 4 is a front view of the work 20W, and FIG. 5 is a plan view of the work 20W. FIG. 6 is a perspective view of the work 20W.

In the first cutting step, as shown by arrow a1 in FIG. 4, the first cutting blade 32 moves from position P1 to position P2, mainly in the Z direction (one direction of the Z axis) and slightly in the Y direction (Y). In the intermediate process, the second cutting blade 33 moves in the Y and Z directions so as to reach the position P3, and in the second cutting process, as shown by the arrow a2 in FIG. As shown by the arrow a3 in FIG. 4, the second cutting blade 32 moves from the position P3 to the position P4 mainly in the Y direction and slightly in the Z direction.

In this way, the cutting process is performed by moving in one direction in both the Z-axis direction and the Y-axis direction, so that the processing can be performed smoothly in a short time, and the movements of the cutting blades 32 and 33 are stable, so that the processing accuracy is also high. Easy to secure.

Since the first mounting portion 320 (first cutting blade 32) and the second mounting portion 330 (second cutting blade 33) are arranged at a predetermined interval L, interference between the cutting blades 32 and 33 should be avoided. By reducing the predetermined interval L (here, 25 mm), the processing can be performed more smoothly and in a short time.

Further, in the first cutting step, the machining can be performed only by moving in the Z direction, but since the movement in the Y direction is also added, it is possible to avoid the concentration of the load on a part of the cutting edge 32a, and the cutting edge 32a Uneven wear can be suppressed.

〔others〕
Although the embodiments of the present invention have been described above, the present invention can be implemented by variously modifying such embodiments without departing from the spirit of the present invention.
For example, in the above embodiment, the cutting blades for hard skiving are applied to the cutting blades 32 and 33, but the cutting blades for hard turning may be applied.

Further, in the above embodiment, the machining tool 20 is fixed to the tool post 13 of the swivel turret 14, but the machining tool 20 may be fixed to the tool post that is not the swivel turret type.
Further, the movement of the holder 31 (movement of the cutting blades 32 and 33) and the cutting location in the above embodiment are examples, and for example, the outer peripheral surface 22F of the shaft portion to be cut is not limited to the one shown in the drawing.

10 Work mount 11 Clamping device 12 Tail center (Pushing center)
13 Turret 14 Swivel turret 20W work (continuously variable transmission pulley)
21 Fixed sheave 21F Sheave surface 22 Pulley shaft (shaft)
22F Shaft outer peripheral surface 23 1st shaft 23a 1st shaft 23 tip 24 2nd shaft 24a 2nd shaft 24 tip 30 Machining tool 31 Holder 32 1st cutting blade 32a 1st cutting blade 32 Blade edge 33 2nd cutting blade 33a Cutting edge of 2nd cutting blade 33 311 Mounting base 312 Cutting blade mounting part 313 1st facing surface 314 2nd facing surface 315 Corner part 316 Meat cutting part 317 Reinforcing meat part 318 Corner part 315 Intermediate part in the extending direction 319 Bolt hole 320 1st mounting part 330 2nd mounting part

Claims (7)

A machining tool for machining a workpiece as a continuously variable transmission pulley having a sheave surface and an outer peripheral surface of a shaft portion.
The first cutting blade, which is a CBN insert that cuts the outer peripheral surface of the shaft portion,
A second cutting blade, which is a CBN insert that cuts the sheave surface,
Said first cutting edge and the second cutting blade is mounted, and a holder that will be secured directly to the tool rest,
The holder
A first facing surface that faces the direction of the outer peripheral surface of the shaft portion during cutting,
A second facing surface that faces the direction of the sheave surface during cutting,
A corner portion where the first facing surface and the second facing surface intersect,
A first mounting portion arranged at a position adjacent to the corner portion on the first facing surface and mounting the first cutting blade, and a first mounting portion.
A machining tool characterized by having a second mounting portion arranged at a position adjacent to the corner portion on the second facing surface and mounting the second cutting blade. The holder is formed into a block shape, and the mounting base is attached to the tool rest located at the side of the workpiece, to an edge of said mounting base, a projecting said first opposing surface from said mounting base A cutting blade mounting portion having the second facing surface and the corner portion is provided, and the other edge side of the mounting base portion opposite to the second facing surface of the cutting blade mounting portion is partially. The machining tool according to claim 1, characterized in that it has been scraped off. The second aspect of the present invention is described in claim 2, wherein a reinforcing wall portion for applying a back component force by the second cutting blade is formed behind the second facing surface of the cutting blade mounting portion. Machining tool. Any one of claims 1 to 3, wherein the first mounting portion and the second mounting portion are arranged at a predetermined interval along a direction in which the corner portion extends. Machining tools described in the section. The machining tool according to any one of claims 1 to 4, wherein the first cutting blade and the second cutting blade are cutting blades for hard skiving that perform wide cutting. .. A tool post to which the machining tool according to any one of claims 1 to 5 is attached, and
A processing apparatus including a work mounting base on which the work is aligned and mounted. A processing method for processing the work using the processing apparatus according to claim 6.
The Z-axis direction, which is the axial direction of the work mount, is from the side of the outer peripheral surface of the shaft portion that is separated from the sheave surface to the side that approaches the work that is centered and mounted on the work mount. The first cutting step of cutting the outer peripheral surface of the shaft portion by the first cutting blade while moving the holder.
After that, an intermediate step of moving the holder in the Y-axis direction orthogonal to the Z-axis direction so that the second cutting blade reaches the outer peripheral edge of the sheave surface,
After that, a second cutting step of cutting the sheave surface with the second cutting blade while moving the holder in the Y-axis direction from the outer peripheral edge of the sheave surface to the inner peripheral side with respect to the work. A processing method characterized by having.

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