JP6233580B2 - Support tool for machining tools - Google Patents

Description

  The present invention relates to a support tool for a processing tool.

  In manufacturing a mold or the like, when machining a deep groove or the like having a narrow width (for example, a width of 2 mm or less), conventionally, electric discharge machining is used instead of cutting with a machining tool. The reason why the cutting process is not used will be explained. A machining tool with a high L / D (ratio between the protruding amount of the machining tool and the diameter) (hereinafter referred to as “high L / D”) is required for machining the deep groove. Become. This is because when this high L / D processing tool is used, tool breakage / deflection or processing vibration occurs, and processing accuracy is impaired. Here, the high L / D is L / D> 30. The tool breakage / deflection occurs when the rigidity of the machining tool loses the cutting resistance generated in the direction orthogonal to the axial direction of the tool. In addition, when the machining tool is a rotary tool, the machining vibration is intermittent cutting in which the cutting blade is periodically separated from the workpiece, and then the above-described deflection and deflection return are repeated, so that the cutting blade moves against the workpiece. Thus, a large separation and a bite are repeated irregularly and occur as a chatter phenomenon. On the other hand, as an invention for suppressing the chatter phenomenon, an apparatus for supporting a rotating processing tool such as an end mill is disclosed (for example, see Patent Documents 1 and 2).

JP-A-8-257823 JP 2003-136324 A

However, the above-mentioned electric discharge machining requires training in the operation of a dedicated electric discharge machine, and it takes time to move the workpiece to the dedicated equipment, prepare the electrodes, etc., and perform actual machining, and the cost is high. there were.
On the other hand, in order to machine a deep groove having a small width with high accuracy using a high L / D machining tool, it is necessary to suppress the deflection of the machining tool and the machining vibration. However, although the conventional support device suppresses the chatter phenomenon of the machining tool, it does not suppress breakage / deflection of the tool.
This invention is made | formed in view of the said subject, The place made into the objective is to raise the precision of the cutting process by a processing tool.

(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention. Therefore, while considering the best mode for carrying out the invention, some of the constituent elements in each section are replaced, deleted, or further added with other constituent elements. It can be included in the range.

(1) A support tool for a machining tool held on a spindle of a machining head of a machine tool, which is in contact with a base portion fixed to the machining head and a part of an outer periphery near the tip of the machining tool, One support portion, and the support portion extends from the base portion to the vicinity of the tip of the processing tool, and is disposed at least in the direction in which the processing tool bends when the workpiece is processed by the processing tool. width in the traveling direction of the tool is less than the width of the contact portion between the workpiece of the machining tool, it saw including a backup member, wherein the base unit includes retainer that secures the machining tool to the spindle of the machining head Including an annular portion fixed to the machining head, and the backup member at least when the workpiece is machined by the machining tool. A plate-like member having a rectangular cross section extending in the extending direction extending from the base portion to the vicinity of the tip of the processing tool in a manner avoiding the fixing tool in parallel with the traveling direction of the processing tool on the rear side in the traveling direction of the tool The plate-like member includes a first plate-like member extending from the base portion, and a second plate-like member extending from the tip of the first plate-like member to the vicinity of the tip of the processing tool, The first plate member is detachably fixed to the base portion, and the second plate member is detachably fixed to the first plate member. (Claim 1).

(2) In the above item (1), the support unit includes two support units, and each of the backup members is attached to the annular unit and extends from the base unit. A machining tool support tool disposed in a direction in which the machining tool bends and a direction opposite to the deflection direction when machining the workpiece (Claim 2).

(3) In order to support a machining tool held by the spindle of the machining head of the machine tool, at least one that contacts a base portion fixed to the machining head and a part of the outer periphery in the vicinity of the tip of the machining tool. A support tool for a machining tool using a support tool, wherein the support part extends from the base part to the vicinity of a tip of the machining tool, and a width in a traveling direction of the machining tool is equal to that of the machining tool. A machining tool that includes a backup member that is equal to or less than the width of a contact portion with the workpiece, and that causes the backup member to contact the machining tool at least from the direction of bending of the machining tool when machining the workpiece with the machining tool. Support method.

  Since this invention was comprised in this way, it becomes possible to raise the precision of the cutting process by a processing tool.

It is the schematic which shows the structure of the support tool of the processing tool which concerns on embodiment of this invention, (a) is a front view, (b) is a bottom view. It is the schematic which shows a mode that a deep groove with a narrow width | variety is processed using the processing tool of high L / D. It is the schematic which shows the example which used the support tool of the processing tool shown in FIG. 1 for the processing tool of a 4-axis processing machine. It is a model figure of a cantilever, (a) is a model figure of a processing tool, (b) is a model figure of a support part and a processing tool. It is a schematic sectional drawing of a support part. It is the schematic for demonstrating the rotational force of a processing tool. It is the schematic for demonstrating arrangement | positioning of a support part in the case of considering the cutting resistance by rotation of a processing tool. It is the schematic which shows the structure of the support tool of a processing tool of the form different from FIG. 1, (a) is the front view which showed only the annular part in the AA 'cross section of (b), (b) is a bottom face. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, detailed description of the same or corresponding parts as those of the prior art will be omitted.
FIG. 1 schematically shows a processing tool support 10 according to an embodiment of the present invention. As shown in the figure, the support tool 10 of the processing tool includes two support portions 12 that come into contact with the processing tool 24 from both the left and right sides in the drawing, and a base portion 18 that fixes the support portion 12 to the processing head 26. The processing tool 24 in FIG. 1 is a high L / D processing tool used when processing a deep groove having a narrow width as shown in FIG. 2, and is fixed by a fixing device 30 including a holder 30 a and a chuck 30 b. The main spindle 28 of the machining head 26 is fixed.

  In the example of FIG. 1, the base portion 18 of the support tool 10 includes an annular portion 20 that is fixed to the machining head 26 by the annular portion tightening bolt 32, and two pieces that fix each of the support portions 12 to the annular portion 20. The fixing part 22 is included. The annular portion 20 is a half-shaped annular member, and the inner peripheral surface of the outer wall 20a of the annular portion 20 is pressed against the outer peripheral portion of the processing head 26 by tightening the two annular portion tightening bolts 32 located at opposite positions on the outer periphery. As a result, it is fixed to the machining head 26. Further, a processing tool 24, a fixing tool 30, and a rotation main shaft 28 are disposed in the inner circumferential space of the annular portion 20. The fixing portion 22 is a block-like bracket fixed by welding or the like to the bottom surface of the bottom portion 20b protruding in the inner circumferential direction from the outer wall 20a of the annular portion 20.

  Each of the two support portions 12 includes a backup member 14, and in the example of FIG. 1, the backup member 14 includes a first plate member 16a and a second plate member 16b. 16. The first plate member 16a is fixed to the fixing portion 22 by a support portion fixing bolt 34, and the second plate member 16b is fixed to the first plate member 16a by an intermediate bolt 36. Yes. In other words, the first plate-like member 16a and the second plate-like member 16b can be replaced as necessary for changing the processing tool 24 or the like. Further, as can be confirmed in FIG. 1A, the plate-like member 16 reaches the vicinity of the tip of the processing tool 24 from the fixing portion 22 fixed to the annular portion 20 of the base portion 18, avoiding the fixing tool 30. Thus, it has the shape inclined toward the axial center of the processing tool 24. Further, the thickness of the second plate-like member 16b (the thickness in the vertical direction in FIG. 1B) is equal to or less than the diameter D (see FIG. 2) of the processing tool 24 (the diameter D of the processing tool 24 faces the tip side). In such a case, the diameter is smaller than the smallest diameter. On the other hand, the first plate-like member 16a is not limited in thickness as the second plate-like member 16b, and has a necessary and sufficient thickness for reliably holding the second plate-like member 16b. Yes.

  Further, the support portion 12 is such that the second plate-like member 16 b of the plate-like member 16 contacts a part of the outer periphery near the tip of the processing tool 24. The shape of the contact surface of the second plate member 16b with respect to the processing tool 24 is a shape that follows the outer peripheral surface of the processing tool 24. For example, the taper is tapered so that the diameter D of the processing tool 24 decreases toward the tip side. When attached, the curved surface is inclined along the taper. In addition, the range in which each of the second plate-like members 16b is in contact with the processing tool 24 can be set to an appropriate range in consideration of the cutting resistance received by the processing tool 24 and the like. For example, the contact range in the circumferential direction may be about half of the outer periphery of the processing tool 24. In this case, the two second plate-like members 16b are in contact with each other over substantially the entire outer periphery of the processing tool 24. Become. The second plate-like member 16b is made of, for example, a super steel alloy to which a DLC coat is applied. Lubricating oil is used for a contact portion with the processing tool 24.

  Further, the plate-like member 16 of the support portion 12 is disposed at least in the direction in which the machining tool 24 bends when the workpiece is machined by the machining tool 24. In the example of FIG. 1, the two support portions 12 are illustrated in the drawing so that the processing tool 24 is arranged in parallel with the traveling direction of the processing tool 24 on the rear side and the front side of the processing tool 24 when processing the workpiece. It is arranged in the left-right direction. Therefore, this example shows an arrangement example of the support portion 12 when the machining tool 24 bends in the left direction or the right direction in the drawing at the time of machining. More specifically, as shown in FIG. 2, when forming a deep groove having a width slightly larger than the diameter D of the processing tool 24 on the workpiece 40, the processing tool 24 is reciprocated in the front and back directions on the paper surface. In the figure, the groove is gradually deepened (stepwise) in the downward direction. The processing tool 24 tends to bend in the back direction of the paper surface during the process of moving in the front direction of the paper surface, and tends to bend in the front direction of the paper surface in the process of moving in the back direction of the paper surface. For this reason, when processing the deep groove of FIG. 2, the support tool 10 is disposed on the processing head 26 so that the two support portions 12 shown in FIG. Installed. Further, as in the example of FIG. 3, the support unit 12 of the support tool 10 may have only one configuration according to the direction in which the processing tool 24 bends. And when processing the spigot part etc. to the workpiece | work 40 with the processing tool 24 of a 4-axis processing machine, as shown in FIG. 3, the support part 12 is the direction opposite to the direction in which the processing tool 24 contacts the workpiece | work 40. The support tool 10 is installed such that the second plate-like member 16b is disposed.

Next, the processing tool 24 is a rotary tool with respect to conditions for appropriately supporting the processing tool 24 by the processing tool support tool 10 according to the embodiment of the present invention. A case where there is one unit 12 will be described as an example.
First, the feed rate of the machine tool holding the machining tool 24 is F (mm / min), the pick feed is p (mm), the cutting amount is t (mm), and the feed amount per blade is f (mm / blade). ), Assuming that the rotation speed is S (rpm), the relationship is as shown in [Equation 1].
Further, the cutting efficiency k is expressed as [Equation 2].
Further, the cutting resistance P is expressed as [Equation 3] where the specific cutting resistance is Kc.

4 is a model diagram of a cantilever beam, FIG. 4A is a model diagram of the processing tool 24 alone, and FIG. 4B is a model diagram of the support portion 12 of the support tool 10 and the processing tool 24. It is. In FIG. 4A, assuming that the protruding amount of the processing tool 24 is L, the longitudinal elastic modulus (Young's modulus) is Er, the secondary moment of inertia is Ir, and the bending moment is Mr, the deflection δr is given by [Equation 4]. Shown in
The deflection δr at x = L (point B) is as shown in [Formula 5].

In FIG. 4B, when the distance from the point A to the point B where the plate-like member 16 of the support portion 12 contacts the processing tool 24 is a and the reaction force at the point B is W, the point C From the balance
Then, when transformed, it becomes [Formula 7].
Further, when the longitudinal elastic modulus (Young's modulus) of the plate-like member 16 of the support portion 12 is Eh, the cross-sectional secondary moment is Ih, and the bending moment is Mh, the deflection δh is expressed as [Equation 8].
The deflection δb of the plate-like member 16 at the point B is as shown in [Equation 9].
Here, in order that the plate-like member 16 is an elastic body and the deflection at the point B does not occur, it is sufficient that δb≈0. For example, when δb = 0.0001, 10].

On the other hand, FIG. 5 shows a schematic cross-sectional view of the plate-like member 16 of the support portion 12. From the relationship of the cross-sectional secondary moment,
It becomes. Assuming that the thickness b of the plate-like member 16 formed below the diameter of the processing tool 24 is equal to the diameter of the processing tool 24, the size of h required for supporting the processing tool 24 is expressed by ] And [Equation 11] to [Equation 12].

On the other hand, the deflection δrx at x in FIG.
Thus, the deflection of the machining tool 24 at point B in FIG. 4B is expressed as [Equation 14].
Accordingly, it is preferable to bring the support portion 12 into contact with the machining tool 24 in consideration of the deflection of the machining tool 24 of [Equation 14].

Next, the rotational force of the processing tool 24 that is a rotary tool is considered. In FIG. 6, when the radius of the processing tool 24 is r, the angular velocity is ω, and the specific weight is γ, the centrifugal force Q in the circumferential portion hs is expressed as [Equation 15].
Then, if the vertical stress in the circumferential direction of the portion hs is σ, and the y-axis direction is considered, the vertical stress σ is balanced with the total stress of the small angle dθ inclined by the angle θ from the x-axis. 15]
It becomes. For this reason, when the circumferential speed is v (mm / s),
It becomes.
Here, the relationship between the circumferential speed v (mm / s) and the rotational speed S (rpm) is expressed by [Equation 18].

From the above, the cutting resistance Pr due to the rotation of the processing tool 24 is expressed as follows.
It becomes. For this reason, when installing the support tool 10 in the processing head 26 of the machine tool, from the relationship between P and Pr shown in FIG. 7, [Equation 3], [Equation 5], [Equation 6], [Equation 7]. The cutting resistance may be replaced with the following P ′.
Further, as shown in FIG. 7, in order to receive the cutting resistance P ′ by the support portion 12, the second plate-like member 16 b of the support portion 12 is
It is only necessary to incline the machining tool 24 by the angle η obtained in the above incline with respect to the machining direction in the right direction in the figure. In addition, the form which inclines and contacts with respect to a process direction in this way is not a case where the deep groove of a width | variety slightly larger than the diameter D of the processing tool 24 as shown in FIG. 2 is processed, as shown in FIG. In addition, it shall be applied when processing the width is not extremely limited.

Next, FIG. 8 shows a processing tool support 10 ′ in a form different from FIG. 1 according to the embodiment of the present invention. 8 is different from the support tool 10 in FIG. 1 only in the annular portion 20 ′ of the base portion 18, and the other parts have the same configuration as the support tool 10 in FIG. For this reason, about FIG. 8, only the cyclic | annular part 20 'of the base part 18 is demonstrated, and description of another site | part is abbreviate | omitted.
An annular portion 20 ′ of the base portion 18 in FIG. 8 has an integral annular shape, and is fixed to the machining head 26 from the lower side of FIG. 8A by an annular portion fixing bolt 38. Further, like the annular portion 20 in FIG. 1, a processing tool 24, a fixing device 30, and a rotation main shaft 28 are disposed in the inner circumferential space portion of the annular portion 20 ′ for fixing the support portion 12. The fixing portion 22 is fixed to the bottom surface of the bottom portion 20b of the annular portion 20 ′ by welding or the like.

Now, according to the embodiment of the present invention configured as described above, the following operational effects can be obtained. That is, the processing tool support 10, 10 ′ according to the embodiment of the present invention, as shown in FIGS. 1 and 8, with respect to the processing tool 24 held on the rotary spindle 28 of the processing head 26. The two support portions 12 support the machining tool 24 by contacting a part of the outer periphery near the tip of the machining tool 24. The support portion 12 has a backup member 14 that extends from the base portion 18 fixed to the machining head 26 to the vicinity of the tip of the machining tool 24. The backup member 14 is disposed at least in the direction in which the processing tool 24 bends when the workpiece 40 (see FIGS. 2 and 3) is processed by the processing tool 24, and contacts the processing tool 24. As a result, the cutting force generated in the direction orthogonal to the axial direction of the processing tool 24, which is a cause of deflection generated particularly when using the high L / D processing tool 24, is received by the backup member 14. Deflection and breakage can be suppressed. Furthermore, the deflection of the suppression and co-processing tool 24, the cutting edge of the machining tool 24 is a rotary tool because it is suppressed away irregularly from the workpiece 40, it is possible to increase the cutting precision.

  Further, the processing tool support tools 10 and 10 'according to the embodiment of the present invention are configured so that the backup member 14 of the support portion 12 is perpendicular to the axial direction of the processing tool 24 (FIGS. 1B and 8B). The thickness of b) in the vertical direction is equal to or less than the width of the contact portion of the processing tool 24. That is, the thickness of the backup member 14 in the direction is at least the diameter D of the processing tool 24. For this reason, as shown in FIG. 2, even when machining a deep groove having a width slightly larger than the diameter D of the machining tool 24 using the machining tool 24 having a high L / D, the machining tool 24 is supported. The backup member 14 of the support tool 10, 10 ′ that does not come into contact with the workpiece 40. More specifically, even when the contact portion of the backup member 14 with respect to the processing tool 24 reaches a position deeper than the surface of the workpiece 40 before the processing starts (upper surface in FIG. 2), the width of the groove processed so far is smaller. The backup member 14 having a thickness can support the processing tool 24 without contacting the workpiece 40. As a result, it becomes possible to perform processing of deep grooves having a narrow width, which has conventionally used electric discharge machining, with high accuracy using the high L / D processing tool 24, thereby saving space in equipment and processing time. Can be shortened and processing costs can be reduced.

  Further, in the processing tool support 10, 10 ′ according to the embodiment of the present invention, the annular portions 20, 20 ′ of the base portion 18 are fixed so that the processing tool 24 is fixed to the rotation main shaft 28 of the processing head 26. The tool 30 is fixed to the machining head 26 in such a manner that the tool 30 is passed through the inner periphery. Further, the plate-like member 16 of the backup member 14 extends from the base portion 18 to the vicinity of the tip of the processing tool 24 in a manner that avoids the fixing device 30. As described above, the plate-like member 16 extending from the base portion 18 fixed to the processing head 26 comes into contact with the vicinity of the tip of the processing tool 24 even though the structure does not contact the fixing tool 30. For this reason, it becomes possible to support the processing tool 24 more reliably without obstructing the rotational movement of the processing tool 24 during processing.

Furthermore, the processing tool support tools 10 and 10 'according to the embodiment of the present invention are not limited to the processing of deep grooves having a narrow width as shown in FIG. 2, but are also not limited to the groove width as shown in FIG. It is also useful for this. Further, in the machining not limited to the groove width as shown in FIG. 3, the second plate-like shape of the support portion 12 is taken into consideration as shown in FIG. 7 in consideration of the rotational force when the machining tool 24 is a rotary tool. If the member 16b is tilted with respect to the machining direction and brought into contact with the machining tool 24, it becomes possible to support more stably regardless of the cutting resistance P ′ applied to the machining tool 24.
1 and 8 show an example in which the spindle of the machining head 26 is the rotary spindle 28 and the machining tool 24 is a rotary tool, the machining tool support 10 according to the embodiment of the present invention. 10 ′, the main axis of the processing head 26 may be a fixed main axis, and the processing tool 24 may be a fixed tool. Further, the support tools 10 and 10 'of the processing tool may be integrated with the first plate-like member 16a and the second plate-like member 16b, and further with the fixing portion 22 added thereto. May be.

  10, 10 ′: processing tool support tool, 12: support portion, 14: backup member, 16: plate member, 18: base portion, 20, 20 ′: annular portion, 24: processing tool, 26: processing head, 28: Spindle, 30: Fixing device, 40: Workpiece

Claims (2)

A support tool for a machining tool held on a spindle of a machining head of a machine tool,
A base portion fixed to the processing head, and at least one support portion that contacts a part of the outer periphery in the vicinity of the tip of the processing tool,
The support portion extends from the base portion to the vicinity of the tip of the processing tool, and when the workpiece is processed by the processing tool, the support portion is arranged at least in a direction in which the processing tool is bent, and has a width in the traveling direction of the processing tool. is the width or less of the contact portion between the workpiece machining tool, a back-up member viewed including,
The base portion includes an annular portion that is fixed to the processing head in a mode in which a fixing device that fixes the processing tool to the main shaft of the processing head is passed through the inner periphery.
The back-up member is at least on the rear side in the advancing direction of the machining tool when machining a workpiece with the machining tool, and is parallel to the advancing direction of the machining tool, avoiding the fixing device, and from the base portion. A plate-shaped member having a rectangular section extending in the extending direction extending to the vicinity of the tip of the processing tool,
The plate-like member includes a first plate-like member extending from the base portion, and a second plate-like member extending from the tip of the first plate-like member to the vicinity of the tip of the processing tool. The plate member is detachably fixed to the base portion, and the second plate member is detachably fixed to the first plate member. Support tool. The two support portions include two support portions, each of the backup members being attached to the annular portion and extending from the base portion, and bending of the processing tool when the workpiece is processed by the processing tool. The tool support tool according to claim 1, wherein the tool support tool is disposed in a direction opposite to the direction and the bending direction .