JP4073895B2 - Drilling device for a workpiece having a hole at a position eccentric from the shaft center - Google Patents

Description

  The present invention relates to a hole machining apparatus suitable for a workpiece such as a crankshaft having a pin hole at a position eccentric from an axis.

As a hole drilling device suitable for a workpiece such as a crankshaft having a pin hole at a position eccentric from the shaft center, an invention previously proposed by the present inventors is known (for example, see Patent Document 1).
JP 2003-136377 A (FIG. 1)

Patent document 1 is demonstrated based on the following figures.
FIG. 11 is a diagram for explaining the basic configuration of the prior art. The hole machining apparatus 110 has a shaft center with a machine tool base 111 and a workpiece 114 having a hole 113 clamped at a position eccentric from the shaft center 112. A rotator 116 attached to the machine tool base 111 so as to be rotatable around, a rotating means 117 attached to the machine tool base 111 for rotating the rotator 116, and movable along an orthogonal axis orthogonal to the axis 112. A slide member 118 attached to the rotating body 116, a moving means 119 for sliding the slide member 118 to a predetermined position, and an eccentric cross section in which the inner diameter circle is eccentric with respect to the outer diameter circle. The first eccentric cylinder 121 housed so as to be relatively rotatable, and the first eccentric cylinder 121 is connected to the machine tool base 111 in order to prevent the first eccentric cylinder 121 from idling. A second eccentric cylinder 123 configured to have an eccentric cross section in which an inner diameter circle is eccentric with respect to an outer diameter circle and accommodated in the first eccentric cylinder 121 so as to be relatively rotatable and axially movable; A spindle shaft rotating means 124 housed in the second eccentric cylinder 123 and a tool 126 attached to the spindle shaft 125 of the spindle shaft rotating means 124 are included.

  Reference numeral 141 denotes second eccentric cylinder positioning means. The second eccentric cylinder positioning means 141 is operated when setting the cutting amount of the tool 126 or the like.

142 is a slide block, 143 is an arm, 144 is a feed screw, 145 is a feed motor, and the feed screw 144 is rotated forward by the feed motor 145 to advance the slide block 142, and the spindle shaft rotating means 124 and the free shaft The second eccentric cylinder 123 can be advanced through the joint 146 and the tool 126 can be inserted into the hole 113. That is, the tool 126 is in the standby position.
Further, reference numerals 147 and 148 denote bearings that facilitate relative rotation and relative axis movement.

  The operation of the hole drilling device 110 will be described later in “Best Mode for Carrying Out the Invention”, but the hole 113 is ground with the tool 126 while the workpiece 114 is rotated around the axis 112. be able to. Since the workpiece 114 can also perform the outer diameter machining of the shaft while rotating around the axis 112, a plurality of types of machining can be performed without changing the workpiece 114.

However, when the hole 113 was processed by the hole processing apparatus 110, the following items to be improved were found.
FIG. 12 is a measurement data diagram of roundness based on the prior art, and the actual hole 113 was a heart-shaped distorted circle with respect to the target perfect circle 151. The drawing emphasizes distortion.
The roundness is defined by an interval f between the concentric circles 152 and 153 when the actual hole 113 is sandwiched between the two concentric circles 152 and 153.
When the diameter of the hole 113 was 30 mm, the roundness f was found to be several tens of μm. It is desired to improve the processing accuracy and to set the roundness to 10 μm or less.

  An object of the present invention is to provide a technique capable of improving machining accuracy in a hole machining apparatus for a workpiece having a hole at a position eccentric from an axis.

The present inventors have noted that the conventional holes are heart-shaped. In FIG. 10, the first eccentric cylinder 121 does not rotate due to the anchor action of the anchor means 122. The second eccentric cylinder 123 also does not rotate due to the anchor action of the universal shaft joint 146 during processing. Theoretically, the hole 113 should not be distorted. However, in reality, there is an inevitable gap between the slide member 118 and the first eccentric cylinder 121. If there is a gap, the first eccentric cylinder 121 is expected to swing left and right with the anchor means 122 as a fulcrum. If the first eccentric cylinder 121 is shaken, it is conceivable that the second eccentric cylinder 123 and the tool 126 are shaken, and the hole 113 becomes a heart-shaped distorted circle.
Therefore, the structure of the anchor means 122 was devised so that no biased external force was applied to the first eccentric cylinder 121, and the experiment was repeated. As a result, the roundness could be remarkably increased.

From the above knowledge, the invention according to claim 1 is a machine tool base (11),
A rotating body attached to the machine tool base (11) so as to be rotatable around the axis (12) in a state in which a workpiece (14) having a hole (13) is clamped at a position eccentric from the axis (12). 16)
A rotating means (17) attached to the machine tool base (11) for rotating the rotating body (16);
A slide member (18) attached to the rotating body (16) so as to be movable along an orthogonal axis orthogonal to the axis (12);
Moving means (19) for sliding the slide member (18) to a predetermined position;
A first eccentric cylinder (21) configured with an eccentric cross section in which an inner diameter circle is eccentric with respect to an outer diameter circle, and accommodated in the slide member (19) so as to be relatively rotatable;
Anchor means (60) for securing the first eccentric cylinder (21) to the machine tool base (11) in order not to cause the first eccentric cylinder (21) to idle.
A second eccentric cylinder (23) configured with an eccentric cross section in which an inner diameter circle is eccentric with respect to an outer diameter circle, and housed in the first eccentric cylinder (21) so as to be relatively rotatable and axially movable;
A spindle shaft rotating means (24) housed in the second eccentric cylinder (23);
A tool (26) attached to the spindle shaft (25) of the spindle shaft rotating means (24);
In a drilling device for a workpiece having a hole at a position eccentric from an axial center,
Second eccentric cylinder positioning means (41) for rotating the second eccentric cylinder (23) is provided on the machine tool base (11) substantially on the axis (12), and second eccentric cylinder positioning means (41). ) And the second eccentric cylinder (23) with a universal shaft joint (46),
The anchor means (60) is a cylindrical universal joint (60) surrounding the universal shaft joint (46), and one end of the cylindrical universal joint (60) is mounted on the machine tool base ( 11) and the other end is connected to the first eccentric cylinder (21).

  In the invention according to claim 1, the anchor means is a cylindrical universal joint. By adopting a cylindrical shape, the first eccentric cylinder could be supported uniformly, the tool swinging could be suppressed, and the roundness could be greatly improved.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a cross-sectional view of a hole drilling apparatus according to the present invention. The hole drilling apparatus 10 has a machine tool base 11 and a shaft center in a state where a workpiece 14 having a hole 13 is clamped at a position eccentric from the shaft center 12. A rotary body 16 attached to the machine tool base 11 so as to be rotatable around, a rotating means 17 attached to the machine tool base 11 for rotating the rotary body 16, and movable along an orthogonal axis perpendicular to the axis 12. A slide member 18 attached to the rotary body 16, a moving means 19 for sliding the slide member 18 to a predetermined position, and an eccentric cross section in which an inner diameter circle (explained in FIG. 3) is eccentric with respect to an outer diameter circle. A first eccentric cylinder 21 which is configured and accommodated in the slide member 18 so as to be relatively rotatable, and an anchor means 60 which connects the first eccentric cylinder 21 to the machine tool base 11 so as not to idle the first eccentric cylinder 21; A second eccentric cylinder 23 configured with an eccentric cross section in which an inner diameter circle (explained in FIG. 3) is eccentric with respect to an outer diameter circle, and accommodated in the first eccentric cylinder 21 so as to be relatively rotatable and axially movable; The spindle shaft rotating means 24 accommodated in the second eccentric cylinder 23, and a tool 26 attached to the spindle shaft 25 of the spindle shaft rotating means 24.

  The anchor means 60 employs a cylindrical universal joint that surrounds the universal shaft joint 46. The detailed structure of the cylindrical universal joint 60 as the anchor means will be described later.

Next, a supplementary explanation of the main configuration will be given.
The machine tool base 11 is a fixed or non-movable member corresponding to a bed of a machine tool.
The workpiece 14 is a half crankshaft used for a press-fit assembly type crankshaft, for example.

  The rotating body 16 is a rotating cylinder attached to the machine tool base by bearings 27 (... indicates a plurality, the same applies hereinafter), and includes a rotating main shaft 29 and clamping means 31 and 32 on the front surface. The clamping means 31 and 32 may be any of hydraulic cylinders, mechanical cylinders, and bolts, and any type and structure may be used as long as they are means for fixing the workpiece 14 centered on the rotation main shaft 29 so as not to be laterally displaced.

The rotating unit 17 is a unit that rotates the rotating body 16 and includes, for example, a motor 33, a gear 34, and a gear 35.
The moving means 19 includes, for example, a nut 36 provided on the rotating body 16 and a bolt 37 screwed into the nut 36. A concave portion 38 is provided in the rotating body 16 for operating the bolt 37, and a concave groove 39 is provided in the machine tool base 11 in order to escape the tip of the bolt 37. The bolt 37 can be rotated through a hole (not shown) formed in the machine tool base 11.

The spindle shaft rotating means 24 is preferably a so-called built-in motor.
Reference numeral 41 denotes second eccentric cylinder positioning means (preferably a stepping motor, a synchro motor, or a servo motor). The second eccentric cylinder positioning means 41 is operated when setting the cutting amount of the tool 26 or the like.

The center of the second eccentric cylinder positioning means 41 is displaced upward from the axis 12 by e.
If the center of the second eccentric cylinder positioning means 41 is aligned with the shaft center 12, the tool 26 slightly moves back and forth under the influence of the eccentricity of the first eccentric cylinder 21 during drilling.
By displacing by e, the back and forth movement of the tool 26 can be eliminated.

42 is a slide block, 43 is an arm, 44 is a feed screw, and 45 is a feed motor. The feed motor 44 is rotated forward to cause the slide block 42 to move forward, and the spindle shaft rotating means 24 and the free shaft. The second eccentric cylinder 23 can be advanced through the joint 46 and the tool 26 can be inserted into the hole 13. That is, in the figure, the tool 26 is in the standby position.
Furthermore, 47 and 48 are bearings, which facilitate relative rotation and relative axis movement.

  FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1. A hole 49 having an oval cross section is formed in the rotating body 16, and a slide member 18 is attached to the hole 49 so The first eccentric cylinder 21 is accommodated via the first eccentric cylinder 21, the second eccentric cylinder 23 is accommodated via the bearing 48, and the spindle shaft rotating means 24 is accommodated in the second eccentric cylinder 23. A state in which the tool 26 provided on the spindle shaft rotating means 24 faces the hole 13 of the workpiece 14 is shown.

FIG. 3 is a view obtained by removing the workpiece from FIG. 2, and the first eccentric cylinder 21 is an eccentric cross section in which the inner diameter circle 21b is eccentric with respect to the outer diameter circle 21a, that is, the lower portion is wide and the upper portion is narrow It is a cylinder of a cross section. Since the first eccentric cylinder 21 is a non-rotating member, the wide part is always lower and the narrow part is always upper.
By turning the bolt 37, the first eccentric cylinder 21 and the like can be moved up and down along the ellipse of the hole 49.

  The second eccentric cylinder 23 accommodated in the first eccentric cylinder 21 is also the second eccentric cylinder 23 having an eccentric cross section in which the inner diameter circle 23b is eccentric with respect to the outer diameter circle 23a. Since the second eccentric cylinder 23 is rotated, the upper part is not always wide and the lower part is not always narrow as shown in the figure.

4A to 4C are operation diagrams of the second eccentric cylinder according to the present invention.
In (a), of the two circles surrounding the tool 26, the solid circle is a hole immediately before finishing, and this is referred to as a pilot hole 51. The circle of the imaginary line is a hole after finishing processing, and this is called a finished hole 52. Now, since the tool 26 is in the center of the lower hole 51, the machining does not start even if the tool 26 is turned in this state.

In FIG. 1, the spindle shaft 25, that is, the center 26 g of the tool 26 is displaced by F from the center 23 g of the second eccentric cylinder 23. The first eccentric cylinder 21 is stationary. The second eccentric cylinder 23 is rotated by an angle within the first eccentric cylinder 21. Then, the locus of the center 26 g of the tool 26 draws a circle with a radius F with reference to the center 23 g of the second eccentric cylinder 23.
In FIG. 4A, a center 26g of the tool 26, a center 23g of the second eccentric cylinder 23, and a circle with a radius F are drawn.

When only the second eccentric cylinder 23 is rotated counterclockwise in FIG. 3, the center 26g of the tool moves on a circle having a radius F, and the tool 26 moves to the upper left.
By this movement, the tool 26 can be brought into contact with the prepared hole 51 as shown in FIG. When the second eccentric cylinder 23 of FIG. 3 is further rotated counterclockwise while rotating the tool 26 at a high speed, the tool 26 further moves to the upper left and reaches the finished hole 52 as shown in FIG.
That is, since the center 26g of the tool 26 is decentered by F from the center 23g of the second eccentric cylinder 23, the cutting amount can be determined by turning the second eccentric cylinder 23 by an appropriate angle.

Next, the operation of the hole machining apparatus having the above configuration will be described.
5 (a) and 5 (b) are explanatory views of the operation of the hole drilling apparatus of the present invention.
FIG. 2A is a combination of FIG. 2 and FIG. 4B. For convenience, a white circle 53 is attached to the rotating body 16 as a mark, and a black dot 54 is added to the contact point of the tool 26 as a mark. In this state, while rotating the tool 26 at a high speed, the rotating body 16 starts to rotate clockwise. Then, together with the rotator 16, the workpiece 14 and the slide member 18 start to rotate clockwise. On the other hand, the first eccentric cylinder 21 and the spindle shaft rotating means 24 can move only vertically, horizontally, and diagonally without rotating.

As is clear from the position of the white circle 53, (b) shows that the rotating body 16 and the like have rotated 90 ° and the workpiece 14 has also rotated 90 °. On the other hand, the orientation of the black spot 54 of the tool 26 does not change.
This means that the work piece 14 is turned by 90 ° around the high-speed rotating tool 26, and as a result, a quarter of the hole 13 (90 ° portion) has been machined.

6 (a) and 6 (b) are operation explanatory views of the hole drilling device of the present invention following FIG.
As is clear from the position of the white circle 53, (a) shows that the rotating body 16 and the like have rotated 180 ° and the workpiece 14 has also rotated 180 °. On the other hand, the orientation of the black spot 54 of the tool 26 does not change.
This means that the workpiece 14 is turned by 180 ° around the high-speed rotating tool 26, and as a result, a half turn (180 °) of the hole 13 has been machined.

As is clear from the position of the white circle 53, (b) shows that the rotating body 16 and the like have rotated 270 ° and the workpiece 14 has also rotated 270 °. On the other hand, the orientation of the black spot 54 of the tool 26 does not change.
This means that the workpiece 14 is turned by 270 ° around the high-speed rotating tool 26, and as a result, 3/4 round (270 °) of the hole 13 has been machined.

  If the cutting depth of the tool is controlled as shown in FIGS. 4B and 4C while repeating FIGS. 5A and 5B and FIGS. 6A and 6B, the pilot hole 51 is obtained. Can be finished into a finished hole 52.

FIGS. 7A and 7B are explanatory views of hole and shaft processing according to the present invention.
FIG. 5A is a hole machining diagram. The workpiece 14 is centered on the rotary spindle 29 and clamped by the clamping means 31 and 32, and then the hole 13 is machined by the tool 26 while turning the workpiece 14 (FIG. 5). FIG. 6). At this time, the grindstone 56 is kept waiting.
(B) is a shaft processing diagram, and the tool 26 is kept on standby while the workpiece 14 remains unchanged. Next, the shaft portion 57 is processed by applying the grindstone 56 while rotating the workpiece 14 at a high speed.

  As is apparent from the above description, according to the present invention, the hole machining and the shaft portion machining can be performed in sequence only by setting the workpiece once in the hole machining apparatus. Conventionally, pin hole processing and shaft portion processing are individually processed with different machine tools, so that the number of setup man-hours increases. In this regard, according to the present invention, the number of man-hours for setup can be greatly reduced.

  FIG. 8 is a cross-sectional view of the main part of a cylindrical universal joint according to the present invention. A cylindrical universal joint 60 as an anchor means is a cylinder 61 extending substantially horizontally from the machine tool base 11 (or the first eccentric cylinder 21). A ring 63 is attached to a pair of upper and lower bearings 62, 62, and a pair of arm portions 65 extended from the intermediate cylinder 64 (the front arm portion 65 is not shown) are rotated at 90 ° with respect to the bearing 62. A joint portion 66 attached to the ring 63 is provided.

By attaching the arm portion 65 to the ring 63 so as to be swingable, the inclination angle of the intermediate cylinder 64 can be freely changed. With this change, when the intermediate cylinder 64 tilts also in the direction of the front and back of the drawing, the ring 63 is tilted by the action of the bearings 62 and 62 to enable tilting.
Therefore, the inclination angle of the intermediate shaft 64 can be freely changed by disposing the joint portions 66 and 66 at both ends of the intermediate tube 64.

  FIG. 9 is an overall view of a cylindrical universal joint according to the present invention. The cylindrical universal joint 60 includes joint portions 66 and 66 provided on the machine tool base 11 side and the first eccentric cylinder 21 side, and joints thereof. This is a flexible shaft joint composed of an intermediate tube 64 interposed between the portions 66 and 66. Reference numerals 67 and 68 denote holes for reducing the weight of the intermediate cylinder 64. Reference numeral 69 denotes a cylindrical cover for dust prevention of the universal shaft joint 46 described below.

  The universal shaft joint 46 is a universal joint and includes a pair of joint portions 46a and 46b and an intermediate shaft 46c. The joint portions 46a and 46b exhibit an action that approximates a human joint. On the other hand, the intermediate shaft 46c is a member that ensures the distance between the joint portion 46a and the joint portion 46b, and is not deformed.

  Returning to FIG. 1, when the hole drilling device 10 is in an operating state, the first eccentric cylinder 21 is uniformly locked by the cylindrical universal joint 60, so that the first eccentric cylinder 21 hardly swings around the locking point. .

  FIG. 10 is a measurement data diagram of roundness based on the present invention, and the actual hole 13 was a circle with less distortion with respect to the target perfect circle 77. When the diameter of the hole 13 was 30 mm, the roundness was found to be several μm. It can be said that the machining accuracy (roundness) is 10 times better than that of the conventional apparatus.

  The cylindrical universal joint of the present invention may be a metal flexible cylinder called a metal bellows.

  The hole drilling apparatus of the present invention is suitable for a hole drilling apparatus for a workpiece having a hole at a position eccentric from the axis.

It is sectional drawing of the hole processing apparatus which concerns on this invention. FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1. It is the figure which removed the workpiece from FIG. It is an effect | action figure of the 2nd eccentric cylinder which concerns on this invention. It is operation | movement explanatory drawing of the hole processing apparatus of this invention. FIG. 6 is an operation explanatory view of the drilling device of the present invention following FIG. FIG. 7 is an operation explanatory view of the drilling device of the present invention following FIG. It is principal part sectional drawing of the cylindrical universal joint which concerns on this invention. 1 is an overall view of a cylindrical universal joint according to the present invention. It is a measurement data figure of roundness based on the present invention. It is a figure explaining the basic composition of the conventional technology. It is a measurement data figure of roundness based on a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Hole processing apparatus (Hole processing apparatus of the workpiece which has a hole in the position eccentric from the axial center), 11 ... Machine tool base, 12 ... Axis center, 13 ... Hole, 14 ... Workpiece, 16 ... Rotating body, 17 DESCRIPTION OF SYMBOLS Rotating means, 18 ... Slide member, 19 ... Moving means, 21 ... First eccentric cylinder, 23 ... Second eccentric cylinder, 24 ... Spindle shaft rotating means, 25 ... Spindle shaft, 26 ... Tool, 29 ... Rotating spindle, 31 , 32 ... clamping means, 41 ... second eccentric cylinder positioning means, 46 ... universal shaft joint, 60 ... cylindrical universal joint as anchor means, 64 ... intermediate cylinder, 66 ... joint part.

Claims (1)

Machine tool base (11),
A rotating body attached to the machine tool base (11) so as to be rotatable around the axis (12) in a state in which a workpiece (14) having a hole (13) is clamped at a position eccentric from the axis (12). 16)
A rotating means (17) attached to the machine tool base (11) for rotating the rotating body (16);
A slide member (18) attached to the rotating body (16) so as to be movable along an orthogonal axis orthogonal to the axis (12);
Moving means (19) for sliding the slide member (18) to a predetermined position;
A first eccentric cylinder (21) configured with an eccentric cross section in which an inner diameter circle is eccentric with respect to an outer diameter circle, and accommodated in the slide member (19) so as to be relatively rotatable;
Anchor means (60) for securing the first eccentric cylinder (21) to the machine tool base (11) in order not to cause the first eccentric cylinder (21) to idle.
A second eccentric cylinder (23) configured with an eccentric cross section in which an inner diameter circle is eccentric with respect to an outer diameter circle, and accommodated in the first eccentric cylinder (21) so as to be relatively rotatable and axially movable;
A spindle shaft rotating means (24) housed in the second eccentric cylinder (23);
A tool (26) attached to the spindle shaft (25) of the spindle shaft rotating means (24);
In a drilling device for a workpiece having a hole at a position eccentric from an axial center,
A second eccentric cylinder positioning means (41) for rotating the second eccentric cylinder (23) is provided on the machine tool base (11) substantially on the axis (12), and the second eccentric cylinder positioning means (41). ) And the second eccentric cylinder (23) with a universal shaft joint (46),
The anchor means (60) is a cylindrical universal joint (60) surrounding the universal shaft joint (46), and one end of the cylindrical universal joint (60) is mounted on the machine tool base ( 11) and a hole drilling device for a workpiece having a hole at a position eccentric from the axial center, wherein the other end is connected to the first eccentric cylinder (21).

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