JP2014014884A - Boring device - Google Patents

Abstract

[PROBLEMS] To provide a boring apparatus capable of reliably and easily boring a prepared target hole with a high degree of roundness with a simple configuration and capable of forming a hole with a high degree of processing accuracy. To do.
A boring apparatus according to the present invention performs boring by rotating a tool 1 about an axis C, and has a plurality of directions (X, Y directions) different in the radial direction of the tool 1. The vibration level detection means 2 for detecting the vibration level, and a correction vibration for correcting the difference between the vibration level detected by the vibration level detection means 2 in the small direction (X direction) and the large vibration level (Y direction). Excitation means 3 for applying V at the same frequency as the vibration generated by the rotation of the tool 1 is provided.
[Selection] Figure 2

Description

  The present invention relates to a boring apparatus, and more particularly, to a boring apparatus for boring a prepared hole formed in an object to be machined by rotating a tool around an axis.

  As shown in FIG. 4, the boring apparatus generally includes a tool 1 in which a cutting tool 10 is supported by a holder 11, a main shaft 4 that holds the tool 1, and a bearing 6 that is interposed around the main shaft 4. A rotating system having a base 5 that rotatably supports 4 around its axis C and a motor 7 that rotationally drives the main shaft 4 is provided. When such a boring apparatus is used to rotate the tool 1 about the axis C to cut the inner peripheral surface of the prepared target hole and perform boring to form a hole with a circular cross section, Depending on the machining conditions such as the rotational speed, cutting depth, or natural frequency of the tool 1, the rotational axis C ′ of the tool 1 during machining is eccentric with respect to the original rotational axis C as shown by the chain line in FIG. Or tilted, causing vibration, which causes a reduction in processing accuracy such as roundness of a hole to be formed.

  For this reason, in a boring apparatus, a balance correction surface is generally provided in a rotating system such as the tool 1, the spindle 4, and the motor 7, and the vibration is measured by rotating the tool. The vibration is suppressed by installing a correction weight or forming a correction hole.

  Moreover, patent document 1 is known as a prior art relevant to a boring apparatus. Patent Document 1 is a rotary processing apparatus that includes a tool holder that rotates while being coupled to a spindle and processes a workpiece with a tool, wherein the tool holder holds the tool and is provided with a sliding shaft, It has a moving member that can advance and retreat in the radial direction intersecting the rotation axis direction of the spindle, and a clamp hole portion for inserting the sliding shaft, and the clamp hole portion is reduced in diameter by a restoring force in a state where the external force is released. An elastic clamp member that keeps the sliding shaft immovable, and increases the fluid pressure to be supplied, and applies the increased fluid pressure to the elastic clamp member, thereby expanding the diameter of the clamp hole. And a fluid pressure supply mechanism that enables the sliding shaft to be moved.

  Further, Patent Document 1 discloses that a tool holder is provided with a friction damper portion that absorbs vibration energy generated during machining of a workpiece by sliding friction.

And the following items are described in paragraph number 0026 of patent document 1.
The friction damper portion 54 includes a damper member 58 that is inserted into the groove 56 on the outer periphery of the housing 22 and that can slide and rotate in the circumferential direction. A magnet 60 is embedded in one end surface of the damper member 58 and is fixed to the housing 22 by a magnetic force. When chatter vibration occurs, the damper member 58 is vibrated in the circumferential direction, and is arranged so as to generate friction (friction) with the contact surface of the housing 22.

Further, paragraphs 0045 to 0046 of Patent Document 1 describe the following matters.
Since the sliding shafts 62a and 62b are slightly deformed by the cutting force, circumferential vibration is likely to be generated in the moving member 64 during processing. Therefore, in the first embodiment of Patent Document 1, the friction damper portion 54 acts. In the friction damper portion 54, friction due to the magnetic force from the magnet 60 occurs between the damper member 58 and the contact surface of the housing 22 when the ring-shaped damper member 58 vibrates in the circumferential direction. This frictional energy consumes and absorbs vibration energy and can prevent chattering.

JP 2012-81572 A

  However, among the conventional techniques described above, when a balance correction surface is provided in the rotating system to suppress vibration, there are individual differences in the balance for each rotating system such as the tool 1, the main shaft 4, and the bearing 6. In addition, it is necessary to perform a correction operation in which the measurement of vibration when the tool 1 is rotated and the installation of correction weights on the balance correction surface and the formation of correction hole processing are repeatedly adjusted until the vibration becomes sufficiently small. Therefore, it is troublesome and time consuming and complicated.

  In the case where vibration is suppressed by providing a balance correction surface in the rotating system, when the balance is changed due to wear of the tool 1 or the bearing 6 due to repeated boring, the vibration is again generated. As a result, the vibration cannot be completely suppressed, and it is difficult to maintain the machining accuracy. Furthermore, in the case where a balance correction surface is provided in the rotating system, in order to correct the changed balance, a correction weight is installed on the balance correction surface or a correction hole is formed in a direction in which vibration is reduced again. There is also a problem that it is necessary to repeatedly perform complicated work.

  The vibration is generated on a virtual plane orthogonal to the original rotation axis of the tool (that is, a direction with respect to the radial rotation axis of the tool), for example, the horizontal directions (X direction) orthogonal to each other shown in FIG. Vibration levels such as amplitude are not the same in different directions such as a vertical direction (Y direction), and a difference (this difference is called a vibration direction difference) often occurs. When such a vibration direction difference occurs, as shown in FIG. 6, the rotation trajectory T ′ of the cutting edge of the cutting tool 10 held by the tool 1 rotated around the axis C is also an ellipse or an ellipse, As a result, there has been a problem that machining accuracy is lowered, such as being unable to form a hole with high accuracy roundness. And in the prior art, there was nothing which suppressed a vibration according to a vibration direction difference.

  Moreover, even if it exists in the said patent document 1 among the said prior arts, even if it can absorb and absorb the vibration energy which generate | occur | produces in the circumferential direction at the moving member 64 at the time of a process, a vibration direction difference is not considered. Therefore, as shown in FIG. 5 and FIG. 6, there is a difference in the vibration level in different directions, and as a result, the machining accuracy is lowered, such as being unable to form a hole with high accuracy roundness. There was a problem.

  The present invention has been made in view of the above-described problems, and it is possible to reliably and easily boring a pilot hole to be processed with high accuracy roundness with a simple configuration. An object is to provide a boring apparatus capable of forming a hole with high accuracy.

  In order to achieve the above object, the boring apparatus according to claim 1 is a boring apparatus that performs boring by rotating a tool around an axis, and is provided in a plurality of directions different in the radial direction of the tool. Vibration level detecting means for detecting a vibration level; and vibration applying means for applying a correction vibration for correcting a difference between the vibration level detected by the vibration level detecting means and the direction in which the vibration level is large. It is characterized by that.

  According to the first aspect of the present invention, when the tool is rotated about the axis and the prepared hole to be machined is bored, the vibration level detection means detects vibration levels and vibration frequencies in a plurality of different directions. To do. The vibration means adds a correction vibration that corrects a difference between the vibration level detected by the vibration level detection means and the direction where the vibration level is large at the same frequency as the generated vibration. Thereby, the vibrations in a plurality of directions different from each other in the direction of the rotation diameter of the tool can be balanced at the time of machining, and the difference in vibration direction can be eliminated. As a result, the diameter of the rotation locus of the tool in each direction becomes equal. Therefore, the boring process can be surely and easily performed, and therefore the hole can be formed with a high degree of machining accuracy.

It is sectional drawing shown roughly in order to demonstrate one Embodiment of the boring apparatus of this invention. It is a front view of the boring apparatus of FIG. In the boring apparatus by this invention, it is explanatory drawing which showed the locus | trajectory of the blade edge | tip of the blade tool hold | maintained at the tool rotationally driven around an axis | shaft. It is sectional drawing shown roughly in order to demonstrate an example of the conventional general boring apparatus. It is a front view of the boring apparatus of FIG. In the conventional boring apparatus, it is explanatory drawing which showed the locus | trajectory of the blade edge | tip of the blade tool hold | maintained at the tool rotationally driven around an axis.

One embodiment of the boring apparatus of the present invention will be described in detail with reference to FIGS. In the drawings, the same reference numerals denote the same or corresponding parts.
The boring apparatus of the present invention generally performs boring by rotating the tool 1 about the axis C, and the vibration levels in a plurality of directions (X, Y directions) different in the rotational radial direction of the tool 1 are as follows. The difference between the vibration level detecting means 2 for detecting the vibration frequency and the direction in which the vibration level is small (Y direction) detected by the vibration level detecting means 2 and the direction in which the vibration level is large (X direction) is corrected. A vibration means 3 for applying the corrected vibration V at the same frequency as the vibration generated by the rotation of the tool 1 is provided.

  As shown in FIG. 1, the tool 1 includes a cutting tool 10 that cuts the inner peripheral surface of a prepared target hole, and a holder 11 that holds the cutting tool 10. The holder 11 of the tool 1 is detachably attached to the tip of the main shaft 4. The main shaft 4 is disposed in the base 5. Between the main shaft 4 and the base 5, a bearing 6 is provided for supporting the main shaft 4 and the tool 1 held by the main shaft 4 so as to be rotatable about the axis C thereof. A motor 7 for rotating the main shaft 4 around the axis C is connected to the base end of the main shaft 4. The base 5 is supported by an LM guide 8 (shown only in FIG. 1) for moving the cutting tool 10 relative to the workpiece.

  In this embodiment, the vibration level detection means 2 is a single vibration level (amplitude) in two different directions (directions orthogonal to each other) in the vertical direction (Y direction) and the horizontal direction (X direction) in FIG. , Acceleration, frequency, etc.) are automatically detected.

  In this embodiment, the vibration means 3 is single and has a predetermined vibration level in a predetermined direction (in FIG. 2, at least one of the vertical direction (Y direction) and the horizontal direction (X direction)). It is comprised by the vibration apparatus which can provide (amplitude, an acceleration, a frequency, etc.) with the same frequency as the vibration of the tool 1. FIG.

  As shown in FIG. 2, the vibration level detection means 2 and the vibration means 3 are on the vertical line passing through the rotation axis C of the tool 1 on the end surface of the base 5 on the side where the tool 1 is attached. They are provided in a relationship of being symmetrical with respect to each other with respect to C.

  The vibration level detection means 2 and the vibration means 3 are not limited to a single vibration level detection means 2 and a vibration level detection means 2 in the Y direction and the X direction. , And a pair of sensors that individually detect vibration levels in the Y direction and the X direction. Furthermore, the vibration level detection means 2 can be configured by sensors that respectively detect vibration levels in the radial direction with respect to the rotation axis C of the tool 1 and in directions other than the Y direction and the X direction. In this case, the direction to be excited and the magnitude of vibration can be determined by combining the vibration levels in directions other than the Y direction and the X direction detected by the sensor.

  Further, the vibration means 3 can be constituted by a plurality of vibration devices that individually apply predetermined magnitude vibrations in the Y direction and the X direction. Furthermore, the vibration means 3 can also be configured by a device that can apply vibrations in the radial direction with respect to the rotation axis C of the tool 1 in directions other than the Y direction and the X direction. In this case, it is desirable that the direction of vibration detected by the vibration level detection means 2 and the direction of vibration applied by the vibration means 3 are matched.

  It is to be noted that a difference in vibration level in a predetermined direction (X, Y direction) detected by the vibration level detection means 2 is obtained, and a correction vibration instructed to the vibration means 3 in order to correct this difference. Determining the size and its direction can be performed by a control means having an arithmetic function. Further, the vibration level detection means 2 determines the magnitude and direction of the corrected vibration by obtaining the difference between the detected vibration levels in the predetermined directions (X and Y directions), and the determined contents are the vibration means 3. In addition, the vibration means 3 receives a vibration level signal in a predetermined direction (X, Y direction) detected by the vibration level detection means 2 and receives the vibration level. The magnitude of the correction vibration and the direction thereof may be determined by obtaining the difference between them, and the vibration may be applied according to the determined content.

  In the boring apparatus configured as described above, the holder 11 holding the predetermined cutting tool 10 is attached to the main shaft 4, and the cutting tool 10 is arranged at a predetermined position with respect to the pilot hole to be processed by the LM guide 8. The blade 10 is moved relative to the object to be processed, and the main shaft 4 is rotationally driven by the motor 7 to cut the inner peripheral surface of the prepared hole. At this time, as shown in FIG. 4, if the actual rotation axis C ′ of the cutting tool 10 held by the tool 1 is inclined or decentered with respect to the original rotation axis C, vibration is generated. Become. In the embodiment shown in FIG. 2, the vibration level in the vertical Y direction is relatively small, the vibration level in the horizontal X direction is relatively large, and there is a difference in vibration levels in different directions. Yes. In this case, as shown in FIG. 6, the locus of the cutting edge of the cutting tool 10 held by the tool 1 rotated around the axis C has a relatively small diameter in the Y direction and a diameter in the X direction. It becomes relatively large, and as a result, becomes an ellipse or an ellipse (see T ′ in FIG. 6), and as a result, a hole cannot be formed with high accuracy roundness.

  However, in the boring apparatus according to the present invention, the vibration level detection means 2 provided on the end surface of the base 5 close to the cutting tool 10 for boring the prepared hole, the vibration level in a predetermined direction (Y direction and X direction) Each frequency of vibration is automatically detected. Then, the vibration level in each detected direction is compared, a direction in which the vibration level is large and a direction in which the vibration level is small is determined, a difference between the vibration levels is obtained, and the vibration level applied to the direction in which the vibration level is small is determined. The magnitude (this is referred to as corrected vibration) V and the direction in which it is applied are determined. The direction, magnitude, and direction of the corrected vibration V can be determined by any one of the control means having the calculation function, the vibration level detection means 2, and the vibration means 3 as described above.

  Subsequently, the excitation means 3 applies the corrected vibration V having the determined direction and magnitude to the end surface closest to the machining position of the base 5 at the same frequency as the vibration generated by the rotation of the tool 1. As a result, as shown in FIG. 3, the correction vibration V is applied at the same frequency as the vibration generated by the rotation of the tool 1 in the Y direction where the vibration level is small, and becomes the same as the vibration level in the large X direction. That is, correction is made so that the difference between the X direction with a large vibration level and the small Y direction disappears and balances. Therefore, the rotation trajectory T of the cutting edge of the cutting tool 10 during boring is shaken in the X direction and the Y direction in the same manner, and becomes a substantially circular shape. As a result, the hole can be formed with high accuracy roundness.

  In the present invention, the vibration level in each direction may be detected by the vibration level detection means 2 at all times during operation of the boring apparatus or during boring of each object, and for example, a predetermined number of objects to be processed The vibration level in each direction may be detected by the vibration level detection means 2 every time boring is performed.

  1: Tool, 2: Vibration level detection means, 3: Excitation means, X: Direction in which vibration level is large, Y: Direction in which vibration level is small, V: Correction vibration

Claims (1)

A boring device that boring by rotating a tool around an axis,
Vibration level detection means for detecting vibration levels in different directions in the radial direction of the tool;
A boring apparatus comprising: an oscillating means for applying a correction vibration for correcting a difference between a vibration level detected by the vibration level detecting means and a direction where the vibration level is large.

Images