JP5503918B2 - Table rotation angle detector - Google Patents

Description

  The present invention relates to a table rotation angle detection device for detecting a rotation angle of a work placement table in a machine tool such as a large vertical lathe.

  This type of device includes a rotary encoder for detecting a rotation angle of a table in a machine tool in which a work placement table is supported on a bed so as to be rotatable about a vertical axis. The rotor is provided with a detected pattern along the outer peripheral edge and a sensor for detecting the detected pattern. The rotor is arranged outward in the rotational radial direction of the table and rotates the table by a belt mechanism. It is known that a sensor is fixed to a bed so that a detection pattern of a rotor can be detected.

  In order to accurately know the rotation angle of the table by detecting the rotation angle of the rotor, adjustment work such as centering of the rotor and synchronization with the table is required during assembly of the machine tool.

  In order to perform the adjustment work, the table is actually rotated, and the runout of the rotor is confirmed by an indicator. Before the adjustment work is completed, the table cannot be automatically driven by a machine, and the table must be manually rotated. Some target tables have a diameter of, for example, 3 m, and it is not easy to rotate the table by one adjuster.

  Moreover, it is inevitable that the belt mechanism includes an error in processing accuracy, and it is difficult to accurately detect the angle of the table.

  An object of the present invention is to provide a table rotation angle detection device capable of easily adjusting a rotary encoder at the time of assembling a machine tool and the like and capable of accurately detecting the rotation angle of a table. is there.

  A table rotation angle detection device according to the present invention is supported by a bed so that the table can be rotated coaxially with the table in a machine tool in which a work placement table is supported by the bed so as to be rotatable about a vertical axis. A rotary encoder for detecting a rotation angle of a table and a table is provided. The rotary encoder includes a rotor to which a detection pattern is attached along an outer peripheral edge portion, and a sensor for detecting the detection pattern. The rotor can be fixed to the base so that its radial position can be adjusted, and the sensor can be fixed to the bed so as to detect the detected pattern of the rotor fixed to the base. The rotation of the table can be transmitted to the rotor fixed to the base by the transmission means.

  In the table rotation angle detection device according to the present invention, in order to perform the adjustment work of the rotary encoder, the transmission by the transmission means is released, the rotor is rotated freely together with the base, and the rotor is rotated manually by hand. Then, the position of the rotor in the radial direction may be adjusted so as to eliminate the vibration while the vibration of the rotor is read by the indicator. Therefore, it is not necessary to rotate the table when adjusting the rotary encoder, and adjustment work can be easily performed by only one person. In addition, since the rotor is at the center of rotation of the table and can easily transmit the rotation of the table, the rotation angle of the table can be accurately detected.

  Furthermore, when the transmission means comprises a spring element that can be detachably bridged to the rotor fixed to the table and the base and is inelastic in the table rotation direction, only the rotational force of the table is accurately transmitted to the rotor, Other forces can be absorbed even with some variation.

  If the spring element is composed of two horizontal spring plates arranged on both sides of the rotation center of the base, the rotation of the table can be reliably transmitted to the rotor as a couple by the spring element. .

  In addition, if the table has a central hole that accommodates the rotary encoder and a lid is applied to the upper end opening of the central hole, the rotary encoder is exposed to chips and cutting fluid by the lid during workpiece processing. When the machine tool is assembled, the lid can be opened, and the adjuster can easily adjust the rotary encoder from the table.

  According to the present invention, there is provided a table rotation angle detection device capable of easily adjusting a rotary encoder at the time of assembling a machine tool and the like and accurately detecting the rotation angle of the table.

It is a vertical sectional view around the bed and table of the machine tool according to the present invention. It is a vertical sectional view around the spindle centering device of the machine tool. FIG. 3 is a horizontal sectional view taken along line III-III in FIG. 2. It is explanatory drawing of centering operation | movement by the same spindle centering apparatus. It is a vertical sectional view around the table rotation angle detection device of the machine tool. FIG. 6 is a horizontal sectional view taken along line VI-VI in FIG. 5.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows peripheral parts of a large vertical lathe such as a bed and a table. Although illustration of the periphery of the spindle head is omitted, the spindle is disposed downwardly above the table. The large vertical lathe is provided with a spindle centering device 10 and a table rotation angle detection device 20.

  A guide hole 12 is formed in the top wall of the bed 11 so as to penetrate therethrough. A vertical sleeve 13 is passed through the guide hole 12. A gear shaft 14 is arranged in parallel with the sleeve 13.

  A stepped central hole 22 is formed in the table 21 so as to penetrate the guide hole 12 so as to communicate with the guide hole 12. A vertical cylindrical housing 23 is fixed to the peripheral surface of the center hole 22. A hollow vertical rod 24 is passed through the housing 23. A main radial bearing group 25 is interposed between the inner surface of the housing 23 and the outer surface of the vertical rod 24. A lid 26 is freely opened and closed at the upper end opening of the center hole 22.

  A large gear 27 is fixed to the lower part of the outer peripheral surface of the table 21. The gear shaft 14 has an upper small diameter driven gear 28 and a lower large diameter drive gear 29. A driven gear 28 is meshed with the large gear 27.

  A thrust bearing 31 is interposed between the top surface of the bed 11 and the outer peripheral edge of the bottom surface of the table 21. The thrust bearing 31 has some play with respect to the relative movement in the radial direction between the bed 11 and the table 21.

  2 and 3 mainly show the spindle centering device 10 in detail.

  A plurality of screw holes 41 are formed at equal intervals on the circumference of the top surface of the bed 11 around the axis of the guide hole 12. Between the two adjacent screw holes 41, a rotation pin 42 is provided so as to project upward.

  An eccentric ring 43 is integrally provided at the upper end of the sleeve 13. The eccentric ring 43 forms an eccentric mechanism, and has an outer surface 43a that is rotatably fitted to the circumferential surface of the guide hole 12 and an inner surface 43b that is eccentric with respect to the outer surface 43a. Two engagement holes 44 are formed on the lower end portion of the sleeve 13 in a straight line in the radial direction.

  In the housing 23, the same number of spanner holes 45 as the screw holes 41 are formed so as to penetrate vertically.

  A circular flange 50 is provided near the lower end of the outer surface of the vertical rod 24. The flange lower fitting surface 24a on the outer surface of the vertical rod 24 is fitted to the inner surface 43b of the eccentric ring so as to be freely slidable. The same number of bolt holes 46 as the screw holes 41 are formed in the flange 50. A bolt 47 is screwed into the corresponding screw hole 41 through each bolt hole 46. On the lower surface of the flange 50, a long hole 48 into which the anti-rotation pin 42 is fitted is formed.

  The upper and lower sides in FIG. 3 are the X-axis direction (main axis horizontal movement direction), and the left and right sides are the Y-axis direction (direction orthogonal to the X-axis). In FIG. 3, the central axis B of the eccentric ring inner surface 43b is eccentric in the X-axis direction by the eccentric amount R with respect to the central axis A of the eccentric ring outer surface 43a. A locking pin 42 and a long hole 48 are positioned on a straight line extending in the Y-axis direction through the eccentric ring inner surface central axis B. The long hole 48 has a length extending in the same straight line direction and a width corresponding to the outer diameter of the locking pin 42.

  The centering procedure is as follows. First, the lid 26 is opened. An indicator (not shown) is applied to the vertical rod 24 to adjust the indicator scale. Next, a spanner S (see FIG. 1) is inserted into the spanner hole 45, and all bolts 47 are loosened by the spanner S. As a result, the eccentric ring inner surface central axis B (vertical rod 24 axis) can be pivoted about the eccentric ring outer surface central axis A by an amount corresponding to the inner diameter of the bolt hole 46 being larger than the outer diameter of the bolt 47. In this state, the bar-shaped handle H is passed through the engagement hole 44, the handle H is pushed in the circumferential direction of the sleeve 13, and the sleeve 13 is rotated. Then, the eccentric ring inner surface center axis B is moved on the arc with the eccentric amount R as the rotation radius, with the eccentric ring outer surface center axis A as the center. As the eccentric ring inner surface central axis B moves, the vertical rod 24 is moved while sliding on the top surface of the bed 11 along with the eccentric ring inner surface 43b. During this movement, both side surfaces of the long hole 48 guide the movement of the rotation pin 42, and the rotation of the vertical rod 24 is suppressed by the rotation pin 42. The movement of the table 21 follows the vertical rod 24. This movement amount is absorbed by the thrust bearing 31. When the table 21 is appropriately moved and the centering with the main shaft is confirmed, the bolts 47 are tightened by the spanner S to fix the vertical rod 24 to the bed 11.

  Next, referring to FIG. 4, the amount of movement of the table 21 in the X and Y directions by the eccentric ring 43 is verified.

  In FIG. 4, the eccentric ring outer surface central axis A, the eccentric ring inner surface central axis B, and the eccentric amount R are as described above with reference to FIG.

  It is assumed that the eccentric ring inner surface central axis B has moved to B ′ by an angle θ on an arc with a radius of rotation R. The amount of movement in the Y direction is R · sin θ, and the amount of movement in the X direction is (R−R · cos θ). If the eccentricity R is 5 mm and the adjustment amount, that is, the Y-direction movement amount R · sin θ = 0.1, θ≈1.146, and the error, that is, the X-direction movement amount (R−R · cos θ) ≈0.0001. This amount may be corrected by aligning the origin in the X-axis direction or may be negligible.

  5 and 6 mainly show the table rotation angle detection device 20 in detail.

  An upper shoulder 51 and a lower shoulder 52 are provided on the outer surface of the vertical rod 24. An annular rotor base 53 is received on the upper shoulder 51 and an annular sensor base 54 is received on the lower shoulder 52.

  A sub radial bearing group 55 is interposed between the outer surface of the vertical rod 24 and the inner surface of the rotor base 53. A flange 56 is provided at the lower end of the outer surface of the rotor base 53. An annular rotor 57 is placed on the flange 56. A gear-like detection pattern is continuously engraved on the outer peripheral surface of the rotor 57. A presser plate 58 is placed on the rotor 57. The rotor 57 and the presser plate 58 are fastened to the flange 56 by bolts 59, so that the rotor 57 is fixed on the flange 56. Bolt holes (not described in detail) are formed in the rotor 57 and the presser plate 58. When the bolt 59 is loosened, the position in the radial direction of the rotor 57 can be shifted by the gap due to the difference between the inner and outer diameters of the bolt 59 and the bolt hole.

  The sensor base 54 is fixed on the lower shoulder 52 by a bolt 61. Two sensors 62 are fixed to the upper surface of the outer peripheral edge of the sensor base 54 by fastening bolts 63 so as to face each other across the rotor 57.

  The rotor 57 and the sensor 62 constitute a magnetic rotary encoder 71. The rotary encoder 71 detects the change in the unevenness of the pattern to be detected by magnetism, and detects the rotational angle position of the rotor 57.

  An opening 73 through which the cord 72 of the sensor 62 passes is formed in the sensor base 54. A vertical penetrating through hole 74 is formed in the peripheral wall of the vertical rod 24 so as to communicate with the opening 73 and guide the cord 72 to the lower side of the vertical rod 24.

  A vertical cylindrical spacer 81 is fixed on the center hole 22 so as to surround the rotary encoder 71 and the like. The top surface of the rotor base 53 and the top surface of the spacer 81 are at the same level. Two horizontal spring plates 82 are bridged so as to straddle both top surfaces with an interval of 180 degrees and to make the inner edges face each other with the rotor 57 interposed therebetween. Each spring plate 82 is fixed to the same top surface by a large number of bolts 83 and 84, respectively. By attaching and detaching the bolts 83 and 84, each spring plate 82 can be attached to and detached from the same top surface.

  Adjustment work for centering the rotor 57 is required at the time of assembly or the like. When performing the adjustment work, the spring plate 82 is removed. While loosening the bolt 59 for fixing the rotor 57, it is possible to finely move the rotor 57 in the radial direction, while rotating the rotor 57 manually with an indicator (not shown) applied to the outer peripheral surface of the rotor 57. The runout of the rotor 57 is read by the indicator. While rotating the rotor 57, the rotor 57 is shifted in the radial direction by hitting the outer periphery of the rotor 57 with a soft hammer (not shown), and so on until the runout of one rotation of the rotor 57 becomes equal. Thus, when the adjustment work is completed, each spring plate 82 is then fixed to the top surface of the rotor base 53 and the top surface of the spacer 81, respectively.

  After the centering of the rotor 57 is completed, the rotation center of the table 21 and the rotation center of the rotor 57 are not necessarily coincident. This is because the main radial bearing group 25 and the sub radial bearing group 55 are interposed between the table 21 and the rotor 57.

  Since the rotary encoder 71 is for detecting the rotation angle of the table 21, even if the rotation center of the table 21 and the rotation center of the rotor 57 are slightly decentered, if the required accuracy can be ensured in terms of the angle, its purpose Is achieved.

  If the eccentricity is present, connecting the spacer 81, that is, the table 21 and the rotor 57 with a high-strength member may interfere with the rotational operation of the rotor 57. However, only the rotational force of the table 21 is applied to the rotor 57. It is preferable that other force fluctuations can be absorbed. By adopting the spring plate 82, this is possible.

  In the above, instead of the two spring plates 82, one annular spring plate that is continuous over the entire circumference may be adopted. In this case, it is inconvenient if the spring force of the spring plate is too strong than necessary, and a hole may be made at a suitable position of the spring plate to weaken this.

  Conversely, three or more spring plates may be arranged at equiangular intervals around the center of rotation of the base.

  The table angle detection device according to the present invention is suitable for achieving detection of the rotation angle of the workpiece mounting table in a machine tool such as a large vertical lathe.

11 beds
21 tables
53 base
57 Rotor
62 sensors
71 Rotary encoder
82 Transmission means

Claims (4)

In a machine tool in which a work placement table is supported by a bed so as to be rotatable about a vertical axis, a base supported by the bed so that the table can rotate independently of the table on the same axis as the table, and a table A rotary encoder for detecting the rotation angle of the rotor, and the rotary encoder comprises a rotor to which a detected pattern is attached along the outer peripheral edge portion, and a sensor for detecting the detected pattern, The rotor can be fixed to the base so that its radial position can be adjusted, and the sensor can be fixed to the bed so that the detected pattern of the rotor fixed to the base can be detected. Ri der can transmit the rotation of the table to the rotor which is fixed to the base, also by releasing the transfer by transmitting means, base with The the chromatography data table can be migrated to a state which is rotated independently table rotation angle detecting device.   2. The table rotation angle detection device according to claim 1, wherein the transmission means comprises a spring element that can be detachably bridged to a rotor fixed to the table and the base and is inelastic in the table rotation direction.   The table rotation angle detection device according to claim 2, wherein the spring element is composed of two horizontal spring plates arranged on both sides of the rotation center of the base.   The table rotation angle detection device according to any one of claims 1 to 3, wherein a center hole that accommodates the rotary encoder is formed in the table, and a lid is applied to an upper end opening of the center hole.

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