JP2008213073A - Vibratory machining device and holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately process a machining object member by surely and precisely holding the member. <P>SOLUTION: A vibratory machining device comprises: a holder 12 for holding a tool T; a spindle 11 for detachably having the holder by fitting both cone-shaped tapered sections 22 and 23 and transmitting vibration of an actuator 10 to the holder; and a bearing 13 for supporting a spindle. The holder holds the tool with a shrinkage fit, a node generated by the designated vibration of the actuator is located at an intermediate section 12a between the bearing and the holder in the axial direction, and an antinode is located on a tapered section and a holding hole. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vibration processing device that processes a workpiece while bringing a tool that vibrates in an axial direction into contact with the workpiece, and a tool holding holder that is attached to the vibration processing device.

  2. Description of the Related Art Conventionally, there are vibration processing apparatuses that process difficult-to-cut materials while applying vibration by bringing a tool that vibrates at high frequency into contact with a hard-to-cut material that is difficult to process such as silicon, ceramics, and cemented carbide.

  This vibration machining apparatus includes an actuator (vibration source) that generates vibration energy, a vibrating body that efficiently transmits the vibration energy of the actuator to a tool, and the like.

  Further, the vibration machining apparatus can perform so-called drilling and milling by using a vibrating body as a spindle and rotatably supporting the spindle by a bearing as a support member. In this case, the spindle and the bearing of the vibration processing apparatus constitute a rotor.

  In order to use various tools, the vibration machining apparatus grips the tool with high accuracy and reliability, and includes a tool gripping portion on the spindle of the rotor (Patent Document 1).

JP 2000-334603 A

  By the way, the tool gripping part in the vibration processing apparatus must have functions such as transmitting vibration energy of the actuator to the tool and minimizing the tool swing due to the rotation of the rotor as much as possible. If the vibration energy is not reliably transmitted to the tool, the energy is lost and the tool does not vibrate. In addition, the tool is dropped and the energy loss is replaced with heat, causing problems such as thermal expansion and burning. In addition, the swing of the spindle also causes a reduction in machining accuracy. In particular, in processing with a small tool diameter, in which processing with the aid of vibration (vibration-assisted processing) is dominant, tool breakage and tool wear are caused.

  There is a widely used collet chuck in the tool gripping portion. Since the collet chuck has a flexible elastic body, it is difficult to transmit high-frequency vibration energy.

  There is also a holder that is detachably attached to the spindle as a tool gripping part. The holder is formed with a gap fitting hole that creates a slight gap with respect to the tool. For this reason, when the tool is inserted into the hole and fastened with bolts, or bonded or joined, the tool centering work to reduce runout is complicated and difficult, and high processing There is a problem that a technique is necessary, and that a tool cannot be changed.

  An object of the present invention is to provide a vibration processing apparatus that reliably and accurately holds a tool to process a workpiece.

  An object of the present invention is to provide a tool holder that can hold a tool in a vibration machining apparatus with high accuracy and improve the machining accuracy of a workpiece by the tool.

The vibration processing apparatus of the present invention is
While the tool that vibrates in the axial direction is brought into contact with the workpiece, and the vibration is applied, the workpiece is processed,
A holder for holding the tool by a holding part;
A spindle that detachably attaches the holder by fitting conical taper portions and transmits vibrations of a vibration source to the holder;
A bearing for supporting the spindle,
The holder holds the tool by shrink fitting in the holding part,
A node generated by a predetermined frequency of the vibration source is located at an intermediate portion in the axial direction of the bearing and the holder, and an antinode is located at the tapered portion and the holding portion.
It is characterized by that.

The holder of the present invention is
A holder used in the above vibration processing apparatus,
At one end, it is provided with a conical taper convex portion that fits into the conical taper concave portion of the spindle,
The other end is provided with a holding portion for holding the tool by shrink fitting,
In the middle part, with the largest diameter part of the holder,
It is characterized by having.

  In the vibration processing apparatus of the present invention, the holder holds the tool by shrink fitting in the holding portion, so that the tool is securely held by the holder, and the vibration of the vibration source is reliably transmitted to the tool. Therefore, the workpiece can be processed with high accuracy.

  In the vibration processing apparatus of the present invention, since the holder is detachably provided on the spindle by fitting the conical taper portions, tool centering and tool replacement are easy.

  In the vibration machining apparatus of the present invention, the node generated by the predetermined frequency of the vibration source is located at the intermediate portion in the axial direction of the bearing and the holder, so that the influence of the vibration of the spindle and the holder is reduced and securely held. Thus, the processing accuracy of the workpiece can be improved.

  In the holder for the vibration processing apparatus of the present invention, the tool is held by shrink fitting in the holding portion, so that the tool can be securely held and the vibration of the vibration source can be reliably transmitted to the tool. Moreover, the tool run-out can be reduced.

  Since the holder for the vibration processing apparatus of the present invention is detachably attached to the spindle by the conical tapered portion, it is easy to center the tool and change the tool.

  Hereinafter, a vibration machining apparatus according to an embodiment of the present invention and a tool holder held by the vibration machining apparatus will be described with reference to the drawings. The numerical values taken up in the present invention are reference numerical values and do not limit the present invention.

  FIG. 1 is a schematic front view of the vibration processing apparatus. FIG. 2 shows a holder that is attached to the spindle of the vibration processing apparatus of FIG.

  The vibration machining apparatus 1 is configured to machine the workpiece W while bringing the tool T vibrating in the axial direction into contact with the workpiece W and applying vibration. The vibration processing device 1 can perform drilling if a drill is attached as a tool, milling if an end mill is attached, and grinding if a grinding wheel is attached.

  The vibration processing apparatus 1 includes an actuator 10 as a vibration source that generates vibration energy, a spindle 11 designed to efficiently transmit vibration energy to the tool T, and a tool that is detachably attached to the spindle 11 and holds the tool. And a holder 12. The spindle 11 is rotatably supported by a bearing 13. Note that only one bearing is shown, but there are others.

  The holder 12 holds the tool T in the holding hole 21 by shrink fitting.

  At the lower end (the other end) of the holder 12, a holding hole 21 as a holding portion for holding the tool is formed along the axial direction. The inner diameter of the holding hole 21 is slightly smaller than the outer diameter of the shank portion Ta of the tool T at room temperature. When the holder 12 is heated, the holding hole 21 is slightly expanded so that the shank portion Ta of the tool T can be received. As a result, the tool T can be inserted into the holder 12. Thereafter, when the holder 12 is cooled and returned to room temperature, the holding hole 21 is tightened and the shank portion T of the tool T is gripped. As described above, the holder 12 holds the tool T by shrink fitting in the holding hole 21.

  Shrink fitting does not require skilled techniques, but can securely hold the tool T in the holder 12. Further, since the contact area between the holder 12 and the tool T is wide, the transmission efficiency of vibration energy can be increased. Thereby, a tool can be held reliably and processing accuracy of a member to be processed can be improved.

  Furthermore, the center of the tool T and the center of the holder 12 can be matched and held, the center run-out of the tool can be reduced, and the processing accuracy of the workpiece can be improved.

  High attachment accuracy and vibration transmission capability are also required between the holder 12 and the spindle 11. In particular, the tool T is stocked while being attached to the holder 12, and it is necessary to replace the holder 12 together when using another tool.

  Therefore, the holder 12 can be easily attached to and detached from the spindle 11, and at the same time, the vibration energy is reliably transmitted from the spindle 11 to the holder 12 by being always stably attached with high accuracy without being affected by the ability and environment of the operator. Need to be able to.

  Therefore, the holder 12 is formed with a conical tapered convex portion 22. The spindle 11 is formed with a conical tapered concave portion 23 into which the tapered convex portion 22 of the holder 12 is fitted. The taper convex portion 22 and the taper concave portion 23 are fitted with each other with a wide contact area. A male screw 24 is formed at the upper end (one end) of the holder 12, and a female screw 25 into which the male screw 24 is screwed is formed on the spindle 11. For this reason, the holder 12 is fitted so as to be screwed into the spindle 11. In addition, these screws 24 and 25 are not necessarily required. When the screws 24 and 25 are not provided, it is necessary to insert the holder 12 into the spindle 11 vigorously, receive it with the spindle 11, and fit it.

  Thus, since the holder 12 is fitted and attached to the spindle 11, the degree of freedom in the radial direction is restricted, and the holder 12 can be securely attached to the spindle 11 regardless of the work ability of the operator. it can.

  FIG. 3 is a graph showing a result of measuring the static runout in the radial direction of the holder 12 with the measuring instrument S when the holder 12 is attached to and detached from the spindle 11 10 times (10 trials). At the time of attachment, no adjustment work corresponding to centering is performed. Accordingly, it is possible to easily realize a swing around 2 μm or less on average. In addition, the standard deviation around the run-out was 1 μm or less, and it was confirmed that the reproducibility was high.

  In addition, since the effective contact area is larger than the contact surfaces between the cylindrical end faces, vibration energy can be efficiently transmitted from the spindle 11 to the holder 12. In order to comprehensively evaluate the above-described characteristics, the shrink-fitting and removing work between the tool T and the holder 12 and the attaching / detaching / removing work of the holder 11 with respect to the spindle 12 are repeated five times (5 trials). FIG. 4 shows the results of measuring the change in run-out at the tip of the tool (carbide shaft with a diameter of 4 mm) with the measuring instrument S.

  The characteristics shown in FIG. 4 are characteristics that directly affect the machining accuracy. According to FIG. 4, the average value of the run-out is 2.6 μm, and the standard deviation is 1.3 μm. The size of the run-out is about the same level as that of a general tool gripping part such as a collet chuck, and it was confirmed that the holder 12 has a sufficient gripping accuracy. In addition, it is confirmed that the vibration energy generated by the actuator 10 is transmitted to the tool T, so that the vibration processing apparatus 1 can be superior to the processing (vibration-assisted processing) with the help of vibration.

  In the above configuration, the vibration processing apparatus 1 is configured to process the workpiece while the tool T is vibrated in the axial direction by the actuator 10 and brought into contact with the workpiece W to be vibrated. When the amplitude in the axial direction of the tool T is 1 μm, the vibration frequency is 60 kHz ± 500 Hz, the diameter of the tool T is 3 mm, and the protruding length from the holder 12 is 12 mm, the spindle 11 and the holder 12 are as shown in FIG. In addition, vibration node A and belly B occur. The node A is a portion with a small amplitude in the axial direction, and the antinode B is a portion with a large amplitude in the axial direction.

  The node A is located in the bearing 13 and the portion 12a having the maximum diameter as a holder in the middle portion of the holder 12 in the axial direction. The belly B is located at the tapered portions 22 and 23, the portion of the holding hole 21 of the holder as the holding portion, and the tip of the tool T.

  The positions of the nodes and the abdomen are determined by the diameter, length, material, etc. of the spindle, holder, tool, etc., and are not determined by analyzing vibrations but are experimentally determined.

  Since the node A is located on the bearing 13, the spindle 11 can be supported by the bearing 13 with less influence of vibration, and the spindle 11 can be smoothly rotated by a motor (not shown).

  Further, when the node A is positioned at the maximum diameter portion 12a of the holder 12, unnecessary axial inertia force is not generated in the holder 12, and predetermined vibration is reliably transmitted to the tool T. Thus, the processing accuracy of the workpiece can be improved.

  Even if the node B is located at the tapered portions 22 and 23 and the holding hole 21, the spindle and the holder are securely connected by the tapered portions 22 and 23, and the holder and the tool are securely connected by shrink fitting. Since it is a part, there is no risk of dropping off. In addition, energy loss is reduced, and problems such as thermal expansion and burning are eliminated.

  Further, when the antinode B is located at the tip of the tool, the vibration processing device 1 can reliably transmit a predetermined vibration to the workpiece and improve the processing accuracy.

(A) is a schematic front view of the vibration processing apparatus in the embodiment of the present invention. (B) is a graph which shows the amplitude of an axial direction. (A) is a half cross-sectional view of a holder attached to the spindle of the vibration processing apparatus of FIG. (B) is a bottom view of (a). (A) is a graph of the result of measuring the static runout in the radial direction of the holder with a measuring instrument when the holder is attached to and detached from the spindle 10 times (number of trials 10 times). (B) is a figure which shows a measurement state. (A) shows the change in the run-out at the tip of the tool when the shrink fit and removal work between the tool and the holder and the work for removing the holder from the spindle are repeated 5 times (5 trials). It is a graph of the result measured with the measuring device. (B) is a figure which shows a measurement state.

Explanation of symbols

Section A B Belly T Tool Ta Shank W Workpiece member S Measuring instrument 1 Vibration processing device 10 Actuator (vibration source)
11 Spindle 12 Holder 12a Maximum diameter portion of the holder (intermediate portion of the holder in the axial direction)
13 Bearing 21 Holding hole (holding part)
22 Taper convex part (taper part)
23 Tapered recess (tapered part)
24 male screw 25 female screw

Claims (2)

In a vibration processing apparatus for processing the workpiece while bringing a tool that vibrates in the axial direction into contact with the workpiece and applying vibration,
A holder for holding the tool by a holding part;
A spindle that detachably attaches the holder by fitting conical taper portions and transmits vibrations of a vibration source to the holder;
A bearing for supporting the spindle,
The holder holds the tool by shrink fitting in the holding part,
A node generated by a predetermined frequency of the vibration source is located at an intermediate portion in the axial direction of the bearing and the holder, and an antinode is located at the tapered portion and the holding portion.
Vibration processing apparatus characterized by that. A holder used in the vibration processing apparatus according to claim 1,
At one end, it is provided with a conical taper convex portion that fits into the conical taper concave portion of the spindle,
The other end is provided with a holding portion for holding the tool by shrink fitting,
In the middle part, with the largest diameter part of the holder,
Holder characterized by that.

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