JP2013022667A - Boring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boring device which allows boring to be repeated with a uniform quality.SOLUTION: The boring device includes: a tool holder 4 which is connected to one end portion of a main shaft 2 through an tilting unit 6 and can rotate together with the main shaft 2; a tool 5 which is held by the tool holder 4; and a draw bar 7 which is inserted into a hollow portion 9 so as to be slidable in a direction along the axis line X of the main shaft 2. The tilting unit 6 includes a fixed part 61 which is fixed to the one end portion of the main shaft 2 at a position apart from the axis line X of the main shaft 2, a base part 60 which is fixed to the tool holder 4, and a connection part 62 which connects the fixed part 61 and base part 60 together in one body, and elastically deforms when the base part 60 moves away from or toward the main shaft 2. A tip of the draw bar 7 can abut against the base part 60 so as to press the base part 60, and a balance member 63 is fixed to the base part 60 at a position on the opposite side from the fixed part 61.

Description

  The present invention relates to a boring apparatus for boring a workpiece.

Conventionally, various apparatuses for boring have been proposed, but in recent years, boring for forming not only a general circular hole but also a non-circular hole has been demanded. . For example, in the boring apparatus of Patent Document 1, a tool provided at the tip of a tool holder extending in a rod shape is projected in the radial direction by a piezoelectric element. Then, the boring process for forming a non-circular hole is performed by rotating the tool holder around the axis while adjusting the protruding length of the tool by the piezoelectric element.
The applicant has previously developed a boring apparatus as shown in FIGS. 8 and 9 (see Japanese Patent Application No. 2010-039047). The boring apparatus 100 includes a hollow main shaft 102 and a table 103 that rotatably supports the main shaft 102 around a predetermined axis 110. Further, the boring apparatus 100 extends in a rod shape and rotates coaxially with the main shaft 102, a tool 111 provided at the tip of the tool holder 101 and protruding in the radial direction, the main shaft 102, and the tool holder 101. And a tilting unit 104 that tilts the tool holder 101 from the axis 110. Further, the boring apparatus 100 includes a draw bar 107 that can reciprocate in the direction of the axis 110 within the main shaft 102, a first driving means (not shown) that rotates the main shaft 102 about the axis 110, and a draw bar 107. Second driving means (not shown) that reciprocates in the direction of the axis 110.
The tilting unit 104 is connected between the draw bar 107 and the tool holder 101 in the direction of the axis 110, and has a base 142 disposed with a gap between one end of the main shaft 102 and one end of the main shaft 102. A fixing portion 144 fixed at a position away from the axis 110 in the radial direction, and a connecting portion 143 that connects the base portion 142 and the fixing portion 144 in the radial direction, and includes at least the fixing portion 144 and the connecting portion 143. One is configured to be elastically deformable.
According to such a configuration, when the spindle 102 is rotated by the first driving means, the tool holder 101 is rotated together with this, and the workpiece w is bored by the tool 111 at the tip of the tool holder 101. . Further, when the draw bar 107 is reciprocated by the second driving means while the tool holder 101 is rotating, the base 142 reciprocates along with this. At this time, the connecting portion 143 supports the base portion 142 while being elastically deformed. When the base portion 142 reciprocates, the tool holder 101 tilts, so that the diameter of the boring hole in boring processing changes. Thereby, a non-circular hole can be formed.

JP-A-11-179605

  However, in the configuration shown in FIG. 8 and FIG. 9 described above, when the boring process is repeatedly performed over a long period of time and the base portion 142 reciprocates and the connecting portion 143 is elastically deformed each time, the connecting portion 143 is restored. In some cases, the force was weakened, and the base 142 could not return to the original position. For this reason, the position of the base 142 is displaced from the original position, and as a result, it has been difficult to maintain a certain machining accuracy. In particular, when the tilting unit 104 is reduced in weight, the deviation may increase, and the rotation balance of the tool holder 101 may be disturbed. Therefore, there remains room for improvement in this respect.

  The present invention has been made to solve the above problem, and an object of the present invention is to provide a boring apparatus capable of repeatedly boring with a certain quality.

  The present invention is a boring apparatus for solving the above-described problem, wherein a rotatable main shaft having a hollow portion along an axial direction, main shaft driving means for driving the main shaft to rotate about the axis, and A tool holder connected to one end of the main shaft via a tilting unit, rotatable with the main shaft, a tool held by the tool holder, and slidable along the axial direction of the main shaft. An inserted draw bar; and draw bar driving means for sliding the draw bar in the axial direction. The tilting unit includes a fixed portion fixed to one end of the main shaft at a position spaced from the axis of the main shaft, a base fixed to the tool holder, and the fixed portion and the base. And a connecting portion that elastically deforms when the base portion moves away from or approaches the main shaft, and the tip of the draw bar presses the base portion. The base can be contacted, and a balance member is fixed to the base at a position opposite to the fixed portion.

  According to such a configuration, even if the base is pressed by the draw bar, the balance member is fixed to the base, so that when the base is released, the base is surely returned to the original position by the weight of the balance member. Return. Therefore, the tilting unit can be kept in its original state, and the quality can be maintained. As a result, it is possible to repeatedly perform boring with a constant quality.

  According to the boring apparatus according to the present invention, boring can be repeatedly performed with a certain quality.

It is a side view of the boring apparatus concerning one embodiment of the present invention. It is sectional drawing which shows the principal part of a boring apparatus. It is sectional drawing which shows the principal part of a boring apparatus. It is the figure which looked at FIG. 3 from the left. It is AA sectional drawing of FIG. It is sectional drawing which shows the principal part of the boring apparatus which concerns on other embodiment. It is AA sectional drawing of FIG. It is a side view of the conventional boring apparatus. It is sectional drawing which shows the principal part of the conventional boring apparatus.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a side view of a boring apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are cross-sectional views showing main parts of the boring apparatus. FIG. 4 is a view of FIG. 3 as viewed from the left. In the following description, the left side of the figure is described as “front” and the right side is described as “rear”.

  The boring apparatus 1 according to this embodiment is an apparatus for boring a workpiece w, and as shown in FIGS. 1 to 4, is rotatable in the direction of the axis X (the left-right direction in FIG. 1). A main spindle 2 and a main spindle driving means 3 for rotating the main spindle 2 around the axis X are provided. The boring apparatus 1 includes a tool holder 4 connected to one end (front end) of the main shaft 2 via a tilting unit 6 and a tool 5 held by the tool holder 4. Further, the boring apparatus 1 includes a draw bar 7 that can slide along the axis X direction, and a draw bar driving means 8 that slides the draw bar 7 in the axis X direction.

  The workpiece w is, for example, an engine piston or the like, and a boring hole can be formed in the workpiece w by the boring apparatus 1. This boring hole is, for example, an insertion hole for a connecting pin that connects an engine piston and a connecting rod. The workpiece w is held by a workpiece holding means (not shown).

  The main shaft 2 is composed of a metal member that extends in the direction of the axis X (the left-right direction in FIG. 1), and has a hollow portion 9 that is formed by cutting through the interior linearly. The hollow portion 9 extends from one end portion (front end portion) to the other end portion (rear end portion) of the main shaft 2 along the axis X direction, and penetrates the main shaft 2. Thereby, the main shaft 2 is formed in a substantially cylindrical shape.

  The main shaft driving means 3 is not particularly limited as long as the main shaft 2 can be driven to rotate about the axis X, but in the present embodiment, a known built-in type motor that can rotate the shaft in the casing. Is used. The spindle driving means 3 is installed on a table 11 movable in the front-rear direction (left-right direction in FIG. 1). By moving the table 11 back and forth along the axis X direction, the spindle driving means 3 and The main shaft 2 can be moved back and forth along the axis X direction. Although the configuration of the table 11 is not particularly limited, in the present embodiment, the table 11 can be moved back and forth along the rail by being disposed on a rail (not shown) on the base 12. The amount of movement of the table 11 can be adjusted as appropriate by the control device 13.

  The tool holder 4 includes a plate-like holder connecting portion 40 and a shaft portion 41 extending from the holder connecting portion 40 in the axis X direction. The holder connecting portion 40 is fixed to the tilting unit 6 with bolts in front of the main shaft 2. Further, the shaft portion 41 extends in a rod shape from the center portion of the holder connecting portion 40 along the axis X toward the front, and the tool 5 is fixed to the tip portion thereof. Such a tool holder 4 is fixed to the main shaft 2 by the tilting unit 6 and rotates together with the rotation of the main shaft 2.

  The tool 5 is not particularly limited as long as the workpiece w can be bored by the rotation of the tool holder 4, but for example, a strong blade made of a sharp metal can be used. The tool 5 is detachably attached to the outer peripheral surface of the front end portion of the shaft portion 41 of the tool holder 4.

  The draw bar 7 is composed of a rod-like member extending in the direction of the axis X, and is inserted into the hollow portion 9 of the main shaft 2 so as to reciprocate along the axis X and to rotate about the axis X. The draw bar 7 is provided with a pressing portion 70 at the tip, and is arranged so that the front end surface of the pressing portion 70 forms a spherical surface and coincides with the front end of the main shaft 2. This pressing part 70 is formed from hardened steel, and when the draw bar 7 moves forward, the pressing part 70 at the tip projects from the front end of the main shaft 2 (the front end of the hollow portion 9) to the front of the main shaft 2, The tilting unit 6 is configured to be pressed. Further, the rear end portion of the draw bar 7 protrudes from the rear end (rear end of the hollow portion 9) of the main shaft 2 to the rear of the main shaft 2 and is connected to the draw bar driving means 8.

  The draw bar driving means 8 is not particularly limited as long as it can reciprocate the draw bar 7 in the axis X direction. For example, a known linear actuator can be used. 5 is a cross-sectional view taken along the line AA in FIG. As shown in FIGS. 1 and 5, the draw bar driving means (linear actuator) 8 of the present embodiment includes a main body case 82 arranged horizontally, a plate-like slider 85 arranged inside the main body case 82, and A plurality of magnets 86 fixed to the left and right sides of the slider 85. The draw bar driving means 8 includes a pair of coil cases 83 and 83 arranged on both the left and right sides of the slider 85 so as to surround the slider 85 to which the magnet 86 is fixed, and a plurality of the case disposed inside each coil case 83. Coil 84, 84.... The draw bar driving means 8 further includes a plurality of support members 87, 87,... For supporting the front end portion and the rear end portion of the slider 85, respectively.

  The slider 85 extends linearly in the front-rear direction (left-right direction in the figure), and is disposed so as to reciprocate back and forth in the body case 2 along the axis X direction. A bearing 90 is fixed to the front end portion of the slider 5, and the rear end portion of the draw bar 7 is fixed to the bearing 90 so as to be rotatable. Thereby, the reciprocating motion of the slider 85 can be transmitted to the draw bar 7 via the bearing 90.

  According to such a draw bar driving means 8, when the coil 84 is energized, the slider 85 moves relative to the body case 82 in the direction of the axis X due to the interaction between the coil 84 and the magnet 86 during energization. Then, the reciprocating motion of the slider 85 is transmitted to the draw bar 7 via the bearing 115. The amount of movement of the slider 85 can be adjusted as appropriate by controlling the amount of current supplied to the coil 84 by a control device (not shown). Moreover, the moving direction of the slider 85 can be converted by converting the energizing direction (current direction) of the coil 84.

  Next, the tilting unit will be described in detail with reference to the accompanying drawings. As shown in FIGS. 2 to 4, the tilting unit 6 includes a base part 60 fixed to the tool holder 4, a fixing part 61 fixed to the front end part of the main shaft 2, one end part of the base part 60, and a fixing part 61. And a connecting portion 62 for connecting the two. Further, the tilting unit 6 includes a balance member 63 fixed to the other end of the base 60.

  The base portion 60 is in contact with the rear end surface of the holder connecting portion 40 of the tool holder 4 and is fixed to the holder connecting portion 40 with a bolt. Further, the base portion 60 includes a contact portion 66 with which a pressing portion 70 at the tip end of the draw bar 7 abuts at a rear end portion thereof, and is configured to be pressed forward by the draw bar 7. Between the base 60 and the front end portion of the main shaft 2, a gap t that changes to a predetermined dimension is provided depending on the protruding amount of the pressing portion 70.

  The fixing portion 61 is fixed to the main shaft 2 so as to protrude forward from the front end of the main shaft 2 at a position separated from the axis X. In the present embodiment, the fixing portion 61 is disposed at a position spaced upward from the axis X in a state where the main shaft 2 is not rotating, and is fixed to the upper end portion of the main shaft 2 with a bolt. The connecting portion 62 is formed in a plate shape, and connects the upper end portion of the base portion 60 and the front end portion of the fixed portion 61.

  The connecting portion 62 connects the fixed portion 61 and the base portion 60 so as to be integrated. The connecting portion 62 is made of metal, and can be elastically deformed when the base portion 60 is separated from or approaches the main shaft. Thereby, when the base 60 is pressed forward by the draw bar 7, the connecting portion 62 is bent by elastic deformation. As a result, as indicated by a dotted line Y in FIG. 3, the base 60 swings around the connecting portion 62 and the tool holder 4 tilts accordingly. As a result, the tool 5 is eccentric from the axis X.

  The balance member 63 is fixed to the base 60 at a position away from the axis X in a direction opposite to the fixing portion 61 (a position opposite to the fixing portion 61). In the present embodiment, the balance member 63 is disposed at a position spaced downward from the axis X in a state where the main shaft 2 is not rotating, and is fixed to the lower end portion of the base portion 60 by bolts. The balance member 63 is not particularly limited as long as the balance member 63 is configured to be a weight with respect to the base 60, but is formed of metal in the present embodiment. The weight of the balance member 63 can be changed as appropriate.

  Subsequently, a method of boring the workpiece w by the boring apparatus 1 having the above-described configuration will be described.

  When boring the workpiece w, first, the position of the workpiece w and the boring apparatus 1 is adjusted, and the spindle driving means 3 is moved with the tool 5 in contact with the workpiece w. By operating, the main shaft 2 is rotated, and the tool holder 4 connected to the main shaft 2 is rotated. Accordingly, the tool 5 fixed to the tool holder 4 is rotated around the axis X, and the workpiece w is bored by the rotation of the tool 5. As a result, a bore having a predetermined diameter is formed in the workpiece w.

  Next, when it is desired to correct the bore diameter of the workpiece w, the draw bar driving means 8 is operated to slide the draw bar 7 forward along the axis X direction. The base portion 60 is pressed forward. When the base 60 is pressed, the fixing portion 61 and the connecting portion 62 of the tool holder 4 are elastically deformed, and the base 60 swings around the connecting portion 62 in the vicinity of the elastic deformation. As a result, the tool holder 4 fixed to the base portion 60 tilts, and the tool 5 fixed to the tip of the tool holder 4 is eccentric from the axis X in the direction indicated by the arrow Y. In this way, the position of the tool 5 is corrected. Subsequently, in this state, when the spindle driving means 3 is operated to rotate the spindle 2 and rotate the tool holder 4 connected to the spindle 2, the tool 5 is rotated and the position of the tool 5 is changed. Since the workpiece w is bored in the corrected state, the bore diameter of the bore hole is corrected, and the workpiece w having a bore hole having a desired diameter is obtained.

  After the boring process is completed, the draw bar driving means 8 is operated in the reverse direction, and the draw bar 7 is pulled backward. Thereby, the pressing of the base 60 is released, and as a result, the tool 5 returns to the original position. At this time, according to the boring apparatus of the present invention, since the balance member 63 is fixed to the base 60, the base 60 is reliably returned to the original position by the weight of the balance member 63. Therefore, the tilting unit 6 can be kept in its original state, and the quality can be maintained. As a result, it is possible to repeatedly perform boring with a certain accuracy.

  As mentioned above, although one Embodiment of this invention was described, the specific aspect of this invention is not limited to the said embodiment.

  For example, in the above-described embodiment, the main shaft driving means 3 uses a built-in type known motor. However, the main shaft driving means 3 may be configured to transmit rotational power from an external motor to the main shaft 2 via a gear or a belt. Even with such a configuration, the main shaft 2 can be rotated about the axis X, and the workpiece w can be bored.

  Moreover, in the said embodiment, although the linear actuator was used as the draw bar drive means 8, it is not limited to this, For example, it has a motor, a ball screw, etc., and employ | adopts the well-known structure which converts rotational motion into linear motion. You can also. Even with such a configuration, the draw bar 7 can be slid in the front-rear direction.

  In the above embodiment, both the fixed portion 61 and the connecting portion 62 are elastically deformed. However, the present invention is not limited to this, and either the fixed portion 61 or the connecting portion 62 is elastically deformed. May be. Also with such a configuration, the base 60 can be rotated.

  Moreover, in the said embodiment, when adjusting the relative position of the boring apparatus 1 and the workpiece w of the axial direction (front-back direction), it can also adjust by moving the table 11, However, Workpiece The workpiece holding means for holding w can also be moved and adjusted.

  Moreover, in the said embodiment, although it was the structure which presses the base 60 of the tilting unit 6 with the draw bar 7, the structure which pulls the base 60 may be sufficient. About this, FIG. 6 is sectional drawing which shows the principal part of the boring apparatus which concerns on other embodiment. FIG. 7 is a cross-sectional view taken along the line AA in FIG. In FIG. 6 or FIG. 7, the same components as those in FIG. 3 or FIG.

  As shown in FIGS. 6 and 7, the tilting unit 6 includes a base portion 60 fixed to the tool holder 4, a fixing portion 61 that fixes the base portion 60 to the tip end portion of the main shaft 2, and one end portion of the base portion 60. A connecting portion 62 that connects the portion 61 is provided. A gap t <b> 2 that changes from a predetermined dimension to 0 is provided between the back surface of the base portion 60 and the front end portion of the main shaft 2 depending on the degree of retraction of the draw bar 7 described later. Further, an elastic material such as an O-ring is disposed to maintain the initial predetermined dimension of the gap t2.

Inside the base 60, a trunnion member 67 connected to the tip of the draw bar 7 is disposed. The trunnion member 67 is disposed at the center of the base 60 and supports the base 60 and the draw bar 7 so that the base 60 rotates with respect to the draw bar 7 via a bearing. According to such a configuration, when the draw bar 7 slides backward (to the right in the drawing), the base 60 is pulled by the draw bar 7, and the base 60 compresses the elastic material (O-ring) while the arrow Z direction. Rocks. As a result, the tool holder 4 fixed to the base portion 60 tilts, and the tool 5 fixed to the tip of the tool holder 4 is eccentric from the axis X in the arrow Z direction. In this way, the position of the tool 5 is corrected.

DESCRIPTION OF SYMBOLS 1 Boring apparatus 2 Spindle 3 Spindle drive means 4 Tool holder 5 Tool 6 Tilt unit 7 Draw bar 8 Draw bar drive means 9 Hollow part 11 Table 40 Connection part 41 Shaft part 60 Base part 61 Fixed part 62 Connection part 63 Balance member 70 Press part

Claims (1)

A rotatable main shaft having a hollow portion along the axial direction;
Spindle driving means for rotating the spindle around the axis; and
A tool holder connected to one end of the main shaft via a tilting unit and rotatable with the main shaft;
A tool held in the tool holder;
A draw bar inserted into the hollow portion so as to be slidable along the axial direction of the main shaft;
A draw bar driving means for sliding the draw bar in the axial direction,
The tilting unit is
A fixed portion fixed to one end of the main shaft at a position spaced from the axis of the main shaft;
A base fixed to the tool holder;
A connecting portion that connects the fixed portion and the base portion so that the base portion and the base portion are integrated, and the connecting portion elastically deforms when the base portion is separated from or approaches the main shaft, and
The tip of the draw bar can contact the base so as to press the base,
A boring apparatus, wherein a balance member is fixed to the base at a position opposite to the fixing portion.

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