JP6381026B2 - Attenuator for rotary cutting tools - Google Patents

Description

  The present invention relates to a damping device that damps vibrations of a rotary cutting tool such as an end mill, and particularly suitable for use in dampening vibrations of a relatively long end mill used for machining a crankshaft. The present invention relates to a damping device for a cutting tool.

  FIG. 8 shows a crankshaft 100 used in an in-line two-cylinder internal combustion engine as an example of the crankshaft. The crankshaft 100 includes two crankpins 101, a total of three crank journals 102 disposed at both ends of the crankpin 101, a crank arm 103 that connects the crankpin 101 and the crank journal 102, And a counterweight 104 formed integrally.

  Conventionally, the processing of the crankshaft has been performed using a dedicated machine called a crankshaft mirror, but it has been desired to process the crankshaft using a versatile machining center or a milling machine. For example, in order to process the crankpin 101 using a machining center, it is necessary to use a long end mill 200 so as not to interfere with the crank arm 103 and the counterweight 104. Then, the crankshaft 100 is rotated so that the end mill 200 follows the rotation of the crankpin 101 so as to be substantially orthogonal to the outer peripheral surface of the crankpin 101.

  However, when cutting is performed using such a long end mill 200, there is a problem that so-called chatter vibration is generated in the tool due to cutting resistance received during the cutting process, and the quality of the processed surface is deteriorated.

  As what can solve such a problem, there has been proposed one in which chatter vibration during cutting is suppressed by bringing a rigid body into contact with a shank of a cutting tool via a viscoelastic body (for example, , See Patent Document 1).

Japanese Patent No. 5131826

By the way, in the thing of patent document 1, the viscoelastic body is directly contacting the shank of the cutting tool.
For this reason, the technique according to Patent Document 1 can be applied without problems to a tool in which the cutting tool is fixed, such as a cutting tool used in a lathe, for example, but the cutting tool itself When the technique according to Patent Document 1 is applied to a rotary cutting tool such as an end mill that rotates, relative friction of the rotary cutting tool with respect to viscoelasticity generates a large frictional force between the two. There is a problem that the rotational load is increased or the viscoelastic body is prematurely worn.

  The present invention has been made in view of the above-described problems, and can reduce chatter vibration of a rotary cutting tool without causing an increase in rotational load of the rotary cutting tool or causing early wear of the viscoelastic body. An object of the present invention is to provide a damping device for a rotary cutting tool that can be suppressed.

In order to achieve the above object, a damping device for a rotary cutting tool according to the first invention comprises:
A rotary cutting tool damping device for damping vibrations of a rotary cutting tool attached to a spindle of a machining head via a tool holder,
An arm member that can support the outer peripheral side of the rotary cutting tool in an auxiliary manner, and has a protruding position that protrudes from the machining head toward the rotary cutting tool and a retreat position that is retracted from the tool holder to the rear machining head. A switchable arm member ;
A sliding member that slidably contacts the outer peripheral surface of the rotary cutting tool when rotating the rotary cutting tool;
A viscoelastic body interposed between the arm member and the sliding member,
The vibration at the time of cutting of the rotary cutting tool is transmitted to the viscoelastic body through the sliding member to be attenuated .

Further, the rotary cutting tool damping device according to the second invention is:
A rotary cutting tool damping device for damping vibrations of a rotary cutting tool attached to a spindle of a machining head via a tool holder,
An arm member capable of supporting the outer peripheral side of the rotary cutting tool in an auxiliary manner;
An attachment block that is disposed at the tip of the arm member and has a flat attachment surface toward the outer peripheral surface of the rotary cutting tool, and also serves as a weight that increases the inertial mass of the tip;
A sliding member fixed to the mounting surface of the mounting block via a viscoelastic body, and in sliding contact with the outer peripheral surface of the rotary cutting tool when rotating the rotary cutting tool;
The vibration at the time of cutting of the rotary cutting tool is transmitted to the viscoelastic body through the sliding member to be attenuated.

In the first or second aspect of the invention, the arm member is configured to extend from a housing attached to the tool holder via a bearing so as to allow rotation of the rotary cutting tool toward the rotary cutting tool . Is preferred (third invention).

According to the rotary cutting tool damping device of the first aspect of the present invention, the sliding member that slides and contacts the outer peripheral surface of the rotary cutting tool when the rotary cutting tool rotates is provided, and chatter vibration during cutting of the rotary cutting tool is provided. Since it is transmitted and attenuated to the viscoelastic body through the sliding member, without causing an increase in the rotational load of the rotary cutting tool or causing early wear of the viscoelastic body, Chatter vibration of the rotary cutting tool can be suppressed.

Also, A over arm member includes a projecting position projecting towards the rotary cutting tool from the machining head side, since it is possible to switch to a retracted position which is retracted to the processing head side of the rear of at least the tool holder, at the time of cutting The arm member set to the protruding position can be set to the retracted position when changing the tool. Thus, for example, when the tool is changed using an ATC (automatic tool changer), it is possible to reliably avoid the interference between the arm member and the ATC.

Also, according to the damping device for a rotary cutting tool of the second invention, the mounting block that functions as a weight for increasing the inertial mass of the tip portion is disposed, and the mounting surface of the mounting block is slid through the viscoelastic body. moving member is secured Runode, it is possible to more effectively suppress the chatter vibration of the rotary cutting tool.

  According to the damping device for the rotary cutting tool of the third invention, the arm member is extended from the housing attached to the tool holder via the bearing to allow the rotary cutting tool to rotate toward the rotary cutting tool. Therefore, for example, when the tool is changed using the ATC, the interference between the arm member and the ATC can be surely avoided without performing a special operation, and the tool can be changed quickly.

It is a principal part perspective view of the machining center to which the attenuation device of the rotary cutting tool which concerns on the 1st Embodiment of this invention was applied. It is the figure which looked at a mode that a crankpin is processed using the machining center to which the damping device was applied from the A arrow direction of FIG. It is a figure (1) explaining the modification of the attenuation device. It is a figure (2) explaining the modification of the same attenuation device. It is a principal part perspective view of the machining center to which the damping device of the rotary cutting tool which concerns on the 2nd Embodiment of this invention was applied. FIG. 6 is a sectional view taken along line B-B in FIG. 5. It is a perspective view which shows a mode that a crankpin is processed using the machining center to which the damping device was applied. It is a top view which shows a mode that a crankpin is processed using the conventional elongate end mill.

  Next, a specific embodiment of the rotary cutting tool damping device according to the present invention will be described with reference to the drawings. Each embodiment described below is an example in which the damping device for a rotary cutting tool of the present invention is applied to an end mill for cutting a crankpin of a crankshaft.

[First Embodiment]
FIG. 1 is a perspective view of a main part of a machining center to which a damping device for a rotary cutting tool according to a first embodiment of the present invention is applied. FIG. 2 shows a state in which the crankpin is machined using a machining center to which the damping device is applied as seen from the direction of the arrow A in FIG.

In FIG. 1, an end mill 1 as a rotary cutting tool is attached via a tool holder 4 to a spindle 3 that is rotatably supported inside a machining head 2 of a machining center.
Under the tool holder 4, a rotary cutting tool damping device 10 (hereinafter simply referred to as “damping device 10”) is disposed so as to be bridged from the machining head 2 to the end mill 1.

<Description of tool holder>
The tool holder 4 is formed by integrally connecting a shank portion 4a that can be attached to and detached from the spindle 3 and a chuck portion 4b that sandwiches the end mill 1 via an ATC gripping portion 4c, and is formed on the outer peripheral surface of the ATC gripping portion 4c. A tool change arm of an automatic tool changer (ATC) (not shown) is engaged with an annular V groove 5 having a substantially V-shaped cross section, and the tool change is performed by inserting / removing the tool holder 4 to / from the spindle 3. Yes.

<Description of attenuation device>
The damping device 10 includes an arm member 11 that can support the outer peripheral side of the end mill 1 in an auxiliary manner.
The arm member 11 has a proximal end portion pivotally supported by a pin 13 on a bracket 12 fixed to the lower surface of the distal end portion of the machining head 2, while the distal end side extends toward a lower position before the blade portion 1 a of the end mill 1. It is made of a rod-like member, and is rotatable in the vertical direction around the pin 13. As shown by a solid line in FIG. 1, a protruding position protruding from the machining head 2 toward the end mill 1 and a two-dot chain line in FIG. As shown, it can swing between a retracted position retracted from the tool holder 4 to the rear machining head 2 side.
The arm member 11 is driven to swing between a protruding position and a retracted position by a swing mechanism using an actuator such as an air cylinder or an electric motor (not shown) as a driving source, so that the protruding position and the retracted position of the arm member 11 are driven. Is switched.

  A distal end functional portion 15 is disposed at the distal end portion of the arm member 11. The distal end functional unit 15 includes a rectangular parallelepiped mounting block 16 that is fixed to the distal end of the arm member 11 and has a flat mounting surface toward the outer peripheral surface of the end mill 1. The mounting block 16 also serves as a weight for adding weight. A sliding member 18 is fixed to the mounting surface of the mounting block 16 via a plate-like viscoelastic body 17 so that the end mill 1 is rotated. The sliding member 18 is in sliding contact with the outer peripheral surface of the end mill 1.

Here, the viscoelastic body 17 has a spring element and a damping element, and has a non-linear spring constant. That is, when the viscoelastic body 17 is deformed by applying a load, the spring constant of the viscoelastic body 17 changes depending on the magnitude of the load. Examples of the viscoelastic body 17 include rubber.
The sliding member 18 is made of a material such as a copper-based alloy impregnated with lubricating oil to give self-lubricating properties, polyacetal (POM), polyamide (PA), polytetrafluoroethylene (PTFE), or the like. ) And the like made of a resin material.

  Further, the width dimension of the arm member 11, the mounting block 16, the viscoelastic body 17 and the sliding member 18 (representatively, the width dimension of the mounting block 16 is represented by the symbol “D1” in FIG. 2) is outside the end mill 1. It is equal to or slightly smaller than the diameter dimension D2 (D1 ≦ D2). As a result, there is nothing that protrudes in the width direction from the end mill 1, so even if the sliding member 18 is brought into contact with the outer peripheral surface of the end mill 1 with the arm member 11 as the protruding position, the arm member 11, the mounting block 16, the adhesive Neither the elastic body 17 nor the sliding member 18 interferes with the crank arm 103 or the counterweight 104, and the later-described damping operation can be performed without hindrance.

In the damping device 10 configured as described above, when the crank pin 101 of the crankshaft (workpiece) 100 is cut, the sliding member 18 is brought into contact with the outer peripheral surface of the end mill 1 with the arm member 11 as a protruding position. . Then, by rotating the spindle 3, the end mill 1 is rotated about its axis and the crankshaft 100 is rotated so that the blade portion 1 a of the end mill 1 is substantially orthogonal to the outer peripheral surface of the crankpin 101. Cutting is performed by bringing the blade portion 1a into contact with the crank pin 101 while following the rotation.
When cutting is performed using such a long end mill 1, chatter vibration occurs due to the cutting resistance received during the cutting process. Chatter vibration is transmitted to the viscoelastic body 17 through the sliding member 18 and is attenuated by the viscoelastic body 17.

<Description of effects>
According to the damping device 10 of the first embodiment, the sliding member 18 that slides into contact with the outer peripheral surface of the end mill 1 when the end mill 1 rotates is provided, and chatter vibration during cutting of the end mill 1 is slid. 18 is transmitted to the viscoelastic body 17 through the damper 18 so as to be attenuated, so that the rotation load of the end mill 1 is not increased, and the viscoelastic body 17 is not worn early. Chatter vibration can be suppressed.
Further, since the arm member 11 can be switched between the protruding position and the retracted position, the arm member 11 that is set to the protruding position at the time of cutting can be set to the retracted position when the tool is changed. Thereby, when exchanging a tool using an ATC (automatic tool changer), it is possible to reliably avoid interference between the arm member 11 and the tip functional unit 15 and the ATC.
Moreover, since the inertial mass of the tip function part 15 increases by adding the weight of the mounting block 15 which also serves as a weight, chatter vibration of the end mill 1 can be more effectively suppressed.

[Description of Modified Example of First Embodiment]
In the first embodiment, the example in which the damping device 10 is provided on the lower side between the machining head 2 and the end mill 1 is shown. However, as shown in FIG. 3, the machining head 2, the end mill 1, The damping device 10 'may be provided on the upper side between the two, and as shown in FIG. 4, the damping devices 10, 10' may be provided on both the upper side and the lower side between the machining head 2 and the end mill 1. good.

[Second Embodiment]
FIG. 5 shows a perspective view of a main part of a machining center to which a damping device for a rotary cutting tool according to a second embodiment of the present invention is applied. 6 is a cross-sectional view taken along the line BB of FIG. 5, and FIG. 7 is a perspective view showing how a crank pin is processed using a machining center to which the damping device is applied. Yes.
In the second embodiment, the same or similar parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof is omitted. In the following, the second embodiment is described. The description will focus on the parts specific to the form.

  As shown in FIG. 5, in the present embodiment, a rotary cutting tool 20 with a support function is attached to the machining head 2 of the machining center. The rotary cutting tool 20 with a support function includes an end mill 1, a tool holder 4, and a tool auxiliary support 21.

<Description of tool auxiliary support>
As shown in FIG. 6, the tool auxiliary support 21 includes a damping device 30 that suppresses chatter vibration during cutting of the end mill 1 and supports the end mill 1 in an auxiliary manner. A housing 23 is provided on the outer peripheral surface of the portion 4b via a bearing 22. A protrusion 23a that protrudes to the outer peripheral side is formed on a part of the outer peripheral surface of the housing 23, and a locking pin 24 is planted on the protruding portion 23a so as to protrude rearward. 24 is engaged with the rotation stop portion 25 of the machining head 2 so that the rotation of the housing 23 relative to the machining head 2 is prevented.

<Description of attenuation device>
The damping device 30 includes a pair of arm members 31 extending from the housing 23 toward the upper and lower positions before the blade portion 1a of the end mill 1. These arm members 31 are arranged at 180 ° across the axis of the end mill 1.

  A distal end functional portion 32 is disposed at the distal end portion of the arm member 31. The distal end functional unit 32 includes a rectangular parallelepiped mounting block 33 that is fixed to the distal end of the arm member 31 and has a flat mounting surface toward the outer peripheral surface of the end mill 1. The mounting block 33 is the same as the previous mounting block 15, and the mounting surface of the mounting block 33 is the same as the previous sliding member 18 via the viscoelastic body 34 similar to the previous viscoelastic body 17. The sliding member 35 is fixed, and when the end mill 1 rotates, the sliding member 35 slides on and contacts the outer peripheral surface of the end mill 1.

  Similarly to the first embodiment, the width dimension of the arm member 31, the mounting block 33, the viscoelastic body 34, and the sliding member 35 (typically, the width dimension of the mounting block 33 is represented as “D1” in FIG. 5). Is equal to or slightly smaller than the outer diameter D2 of the end mill 1 (D1 ≦ D2). Thus, none of the arm member 31, the mounting block 33, the viscoelastic body 34, and the sliding member 35 interferes with the crank arm 103 or the counterweight 104, and a later-described damping operation can be performed without any trouble.

As shown in FIG. 7, when the crank pin 101 is processed, the Z direction orthogonal to the extending direction (X direction) of the end mill 1 and the direction in which the pair of arm members 31 face (Y direction) is the extending direction of the crank pin 101. The rotary cutting tool 20 with a support function is arranged so as to match.
Then, by rotating the spindle 3, the end mill 1 is rotated about its axis and the crankshaft 100 is rotated so that the blade portion 1 a of the end mill 1 is substantially orthogonal to the outer peripheral surface of the crankpin 101. Cutting is performed by bringing the blade portion 1a into contact with the crank pin 101 while following the rotation.
When cutting is performed using such a long end mill 1, chatter vibration occurs due to the cutting resistance received during the cutting process. Chatter vibration is transmitted to the viscoelastic body 34 via the sliding member 35 and is attenuated by the viscoelastic body 34.

<Description of effects>
Also with the damping device 30 of the second embodiment, a sliding member 35 that slides into contact with the outer peripheral surface of the end mill 1 when the end mill 1 rotates is provided, and chatter vibration during cutting of the end mill 1 is slid. Since it is transmitted to the viscoelastic body 34 via the damped member and attenuated, the same effect as that of the damping device 10 of the first embodiment can be obtained.
Further, in the rotary cutting tool 20 with a support function, since the arm member 31 extends from the housing 23 attached to the tool holder 4 via the bearing 22 so as to allow the end mill 1 to rotate toward the end mill 1, the ATC When exchanging the tool using the arm member 31, the arm member 31 and the ATC are not interfered with each other without performing a special operation such as setting the arm member 11 in the protruding position at the time of cutting to the retracted position as in the first embodiment. This can be avoided reliably, and the tool can be replaced quickly by attaching and detaching the rotary cutting tool 20 with a support function.

  As mentioned above, although the damping device of the rotary cutting tool of this invention was demonstrated based on several embodiment, this invention is not limited to the structure described in the said embodiment, In the range which does not deviate from the meaning, it is appropriate. The configuration can be changed.

  For example, in the first embodiment, the arm member 11 is swung around the pin 13 to switch between the protruding position and the retracted position. However, the arm member 11 is taken in and out from the processing head side by a linear movement mechanism. Thus, the protruding position and the retracted position may be switched.

  The damping device for a rotary cutting tool according to the present invention is capable of suppressing chatter vibration of the rotary cutting tool without increasing the rotational load of the rotary cutting tool or causing early wear of the viscoelastic body. Therefore, when using a long rotary cutting tool such as an end mill in a machine tool such as a machining center or a milling machine, it is suitable for applications that suppress chatter vibration during cutting of the rotary cutting tool. Can be used.

1 End mill (rotary cutting tool)
2 Processing head 3 Spindle 4 Tool holder 10, 30 Attenuator 11, 31 Arm member 16, 33 Mounting block (weight)
17, 34 Viscoelastic body 18, 35 Sliding member 22 Bearing 23 Housing

Claims (3)

A rotary cutting tool damping device for damping vibrations of a rotary cutting tool attached to a spindle of a machining head via a tool holder,
An arm member that can support the outer peripheral side of the rotary cutting tool in an auxiliary manner, and has a protruding position that protrudes from the machining head toward the rotary cutting tool and a retreat position that is retracted from the tool holder to the rear machining head. A switchable arm member ;
A sliding member that slidably contacts the outer peripheral surface of the rotary cutting tool when rotating the rotary cutting tool;
A viscoelastic body interposed between the arm member and the sliding member,
A damping device for a rotary cutting tool, wherein vibration during cutting of the rotary cutting tool is transmitted to the viscoelastic body through the sliding member to be attenuated. A rotary cutting tool damping device for damping vibrations of a rotary cutting tool attached to a spindle of a machining head via a tool holder,
An arm member capable of supporting the outer peripheral side of the rotary cutting tool in an auxiliary manner;
An attachment block that is disposed at the tip of the arm member and has a flat attachment surface toward the outer peripheral surface of the rotary cutting tool, and also serves as a weight that increases the inertial mass of the tip;
A sliding member fixed to the mounting surface of the mounting block via a viscoelastic body, and in sliding contact with the outer peripheral surface of the rotary cutting tool when rotating the rotary cutting tool;
A damping device for a rotary cutting tool , wherein vibration during cutting of the rotary cutting tool is transmitted to the viscoelastic body through the sliding member to be attenuated. The attenuation of the rotary cutting tool according to claim 1 or 2 , wherein the arm member extends from a housing attached to the tool holder via a bearing to allow rotation of the rotary cutting tool toward the rotary cutting tool. apparatus.

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