JP7432082B1 - Grinding machine work support device - Google Patents

Abstract

The present invention provides a support device that reduces the amount of displacement in the cutting direction of a grindstone at a grinding point of a workpiece and improves grinding accuracy. A workpiece support device 10 of the present invention rotatably supports both ends and a midway position of a long workpiece W having a circular cross section, and is a workpiece of a grinding machine 1 that grinds the outer circumferential surface of the workpiece W with a grindstone 12. The support device 10 includes an end support part 14 that rotatably supports both ends of the workpiece W, an intermediate support part 13 that rotatably supports an intermediate position of the workpiece W, and an end support part 14 that rotatably supports both ends of the workpiece W. A floating part 17 that moves the end of the workpiece W in a direction perpendicular to the longitudinal direction of the workpiece W is provided to prevent misalignment between the end supporter 14 and the intermediate supporter 13 that respectively support both ends of the workpiece W. If this occurs and the workpiece W is not supported in a straight line and is bent, the floating portion 17 moves in a direction perpendicular to the longitudinal direction of the workpiece W to absorb the misalignment. [Selection diagram] Figure 1

Description

The present invention relates to a workpiece support device that rotatably supports both ends and intermediate positions of a workpiece during grinding, and particularly to a workpiece support device for a grinding machine that grinds a spiral thread groove on the outer peripheral surface of a workpiece.

In order to grind the outer peripheral surface of a long round bar-shaped workpiece with a grinder, it is necessary to reduce the amount of displacement of the workpiece in the cutting direction of the grindstone at the grinding point of the workpiece to which the grindstone is pressed. This is because if the workpiece is displaced in the cutting direction of the grinding wheel during the grinding process, the cross-sectional shape and cross-sectional dimensions of the workpiece after the grinding process will change at some places in the longitudinal direction of the workpiece, which will adversely affect the grinding accuracy. Various support devices are used to reduce this amount of displacement.

Patent Document 1 discloses that a presser movable in the cutting direction of the grinding wheel is provided at a position facing the grindstone across the workpiece, and the amount of displacement in the cutting direction of the grinding wheel that occurs when the grindstone cuts into the workpiece and bends is detected. In addition, a support device is disclosed that moves a presser toward a workpiece based on the detected displacement amount to reduce the amount of deflection of the workpiece during grinding.

Japanese Patent Application Publication No. 2002-1656

However, in the support device described in Patent Document 1, in addition to the displacement of the workpiece that occurs when the grindstone cuts into the workpiece and bends, there are two causes for the displacement of the workpiece in the cutting direction of the grindstone. Conceivable. First, in the support device of Patent Document 1, the workpiece is supported at a total of three points: both ends and the center. However, it is difficult to install the three points at both ends and the center on a perfect straight line, and there is a risk that misalignment will occur between the three points. When misalignment occurs between the three points, the workpiece is slightly bent. If traverse grinding is performed in which the workpiece is moved in parallel in the longitudinal direction relative to the grindstone while the workpiece is bent, the workpiece will be displaced in the cutting direction of the grindstone, resulting in poor grinding accuracy.

The next factor is that in the support device of Patent Document 1, the presser is in contact with the work so as to face the grindstone in the cutting direction of the grindstone. There are shape errors in roundness and cylindricity at the outer diameter of the workpiece, so in a structure where the grindstone contacts the workpiece from the opposite side of the grindstone in the cutting direction, the workpiece may There is a risk of displacement in the cutting direction of the grindstone.

In order to eliminate these causes of displacement of the workpiece in the cutting direction of the grindstone, the support device described in Patent Document 1 includes a sensor that detects the amount of displacement of the workpiece, an actuator that drives the presser, and a control device. This is thought to make the device complicated.

The present invention has been made in view of the above-mentioned problems, and it solves the problem of misalignment caused by supporting the workpiece at three points: both ends and the center, and by the contact between the presser and the workpiece in the cutting direction of the grindstone. To provide a support device that reduces the amount of displacement in the cutting direction of a grindstone at a grinding point of a workpiece and improves grinding accuracy with a simple structure that does not use a control device or the like by eliminating the influence of workpiece shape errors. It is considered that the amount of displacement in the cutting direction of the grindstone, which occurs when the grindstone cuts into the workpiece and bends, can be reduced by providing the necessary rigidity to the workpiece support at the grinding point of the workpiece.

In order to solve the above problems, the work support device of the present invention rotatably supports both ends and intermediate positions of a long workpiece having a circular cross section, and supports the workpiece of a grinding machine that grinds the outer peripheral surface of the workpiece with a grindstone. The apparatus includes an end support part that rotatably supports both ends of the workpiece, an intermediate support part that rotatably supports an intermediate position of the workpiece, and an end support part that supports the end part of the workpiece. A floating part that moves in a direction perpendicular to the longitudinal direction is provided, and misalignment occurs between the end support part and the intermediate support part that respectively support both ends of the workpiece, and the workpiece is not supported in a straight line and bends. In this case, the floating part absorbs the misalignment by moving in a direction perpendicular to the longitudinal direction of the workpiece.

Further, the workpiece support device of the present invention is a workpiece support device for a grinding machine that rotatably supports an intermediate position of a long workpiece having a circular cross section and grinds the outer peripheral surface of the workpiece with a grindstone. The surface is supported at three points in the radial direction, and among the three points, the first support point is located above the axis of the workpiece, and the second and third support points are below the axis of the workpiece, Support position variable parts are provided that are located on both sides of a vertical line passing through the axis of the workpiece, and that make the positions of the second support point and the third support point variable.

According to the workpiece support device of the present invention, the floating portion provided in the end supporter moves the end portion of the workpiece in a direction perpendicular to the longitudinal direction of the workpiece, so that the workpiece can be moved between both ends and the central portion. Even when the workpiece is supported at a point, it is possible to absorb the misalignment between the three points, and it is possible to reduce the amount of displacement in the cutting direction of the grindstone at the grinding point of the workpiece, thereby improving grinding accuracy.

Further, according to the workpiece support device of the present invention, the outer circumferential surface of the workpiece is supported at three points from the radial direction, and among these three points, the first supporting point is on the outer circumferential surface of the workpiece located above the axis of the workpiece. The second and third supporting points are two points on the outer peripheral surface of the workpiece below the axis of the workpiece, so the workpiece can be supported in a direction substantially perpendicular to the cutting direction of the grindstone. It is possible to prevent the workpiece from being pushed in the cutting direction of the grindstone due to a shape error in the outer diameter of the workpiece, reduce the displacement of the workpiece in the cutting direction of the grindstone, and improve grinding accuracy. Furthermore, by changing the positions of the second support point and the third support point and selecting a support position according to the machining conditions of the workpiece, the displacement of the workpiece in the cutting direction of the grinding wheel can be reduced and the grinding process can be improved. Accuracy can be improved.

FIG. 1 is a front view of a grinding machine equipped with a workpiece support device according to a first embodiment of the present invention. (a) Cross-sectional view of the spindle side end support portion of the workpiece support device according to the first embodiment of the present invention, (b) Tailstock side end support portion of the workpiece support device according to the first embodiment of the present invention 2(c) is an enlarged view of the elastic member holding groove of FIG. 2(a). (a) A cross-sectional view of a spindle side end support portion according to a second embodiment of the present invention, and (b) an enlarged view of an elastic member holding groove in FIG. 3(a). (a) A perspective view of a grinding machine equipped with a workpiece support device according to a third embodiment of the present invention, and (b) an enlarged view of a main part of FIG. 4(a). (a) A cross-sectional view of a main part of a workpiece supporting device according to a third embodiment of the present invention, in which a workpiece W is supported by a rod, (b) A cross-sectional view of a main part of a workpiece supporting device according to a third embodiment of the present invention, in which a workpiece W is supported by a rod. FIG. 3 is a cross-sectional view of a main part in which a workpiece W is supported by changing its position. It is a sectional view of the workpiece supporting device concerning a 4th embodiment of the present invention. It is a sectional view of the workpiece supporting device concerning a 5th embodiment of the present invention. It is a perspective view of the lower support part and cage of the workpiece|work support apparatus based on the said embodiment. FIG. 2 is a cross-sectional view for explaining a workpiece supporting method using a conventional workpiece supporting device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The work supporting device of the present invention will be described below based on each embodiment with reference to the drawings. The drawings schematically represent the workpiece support device, the constituent members of the workpiece support device, and the peripheral members of the workpiece support device, and the actual dimensions and dimensional ratios of these devices are the same as the dimensions and dimensional ratios on the drawings. It doesn't necessarily match. Further, unless otherwise specified, for convenience, directions such as up and down are expressed based on the orientation of the workpiece support device shown in FIG. Duplicate explanations will be omitted as appropriate, and the same members may be given the same reference numerals.

(First embodiment)
FIG. 1 shows an example of a screw grinding machine 1 equipped with a workpiece support device 10 of the present invention. The screw grinding machine 1 includes a bed 3 fixed on a floor surface 2, a table 4 movably placed on the bed 3 and reciprocating in a reciprocating direction W1, and a reciprocating motion integrally with the table 4. It is equipped with a headstock 5 and a tailstock 8. The headstock 5 is provided with a spindle rotary disk 6 to which the rotational force of a motor (not shown) is output. At the center of the main shaft rotary disk 6, an output rotary shaft 7 is formed coaxially with the main shaft rotary disk 6. A shaft body 9 is formed on the tailstock 8 coaxially with the output rotation shaft 7 . The workpiece W is rotatably supported between the output rotation shaft 7 and the shaft body 9.

A whetstone stand 11 is provided on the bed 3. The grindstone head 11 does not move in the longitudinal direction of the workpiece W. The work W is ground while moving in the reciprocating direction W1 together with the headstock 5 and tailstock 8 provided on the table 4. In this manner, in this embodiment, traverse grinding is performed in which the workpiece W is moved parallel to the grindstone 12 in the longitudinal direction.

The grindstone head 11 has a structure that allows it to reciprocate in a direction perpendicular to the longitudinal direction of the workpiece W. A disk-shaped grindstone 12 is rotatably supported on the grindstone head 11 and rotated at high speed by a motor (not shown). The grindstone head 11 moves back and forth in a direction perpendicular to the longitudinal direction of the workpiece W, thereby bringing the grindstone 12 into contact with the workpiece W to perform grinding.

An intermediate support portion 13 is provided on the opposite side of the grindstone 12 across the workpiece W. The intermediate support portion 13 prevents the workpiece W from moving in the cutting direction of the grindstone when the grindstone 12 cuts into the workpiece W. The intermediate support part 13 is fixed to the bed 3 and does not move. In this embodiment, the intermediate support portion 13 supports the work W at the position where the grindstone 12 cuts into the work W.

The spindle rotary disk 6 and the tailstock 8 are respectively provided with a spindle side end support part 14a and a tailstock side end support part 14b that rotatably support the workpiece W. As shown in FIGS. 2(a) and 2(b), the spindle side end support part 14a and the tailstock side end support part 14b are arranged so that the end of the workpiece W is supported in a direction perpendicular to the longitudinal direction of the workpiece W. A floating part 17 is provided to move the floating part 17.

The floating portion 17 is arranged between a housing 35 having a cylindrical inner circumferential surface 36, a coupling 18 disposed inside the housing 35, and an inner circumferential surface 36 of the housing 35 and an outer circumferential surface of the coupling 18. It has an elastic member 28 which is made of elastic material.

As shown in FIG. 2(a), the housing 35 is provided with a cylindrical portion 38 extending in the longitudinal direction of the workpiece W, and a flange portion 37 protruding radially from the outer peripheral surface of the cylindrical portion 38. The cylindrical portion 38 has a circular inner circumferential surface 36 when viewed in cross section, and the inner diameter of the inner circumferential surface 36 is set larger than the outer diameter of the coupling 18 . An elastic member 28 is arranged between the inner peripheral surface 36 and the coupling 18. Since one end W7 of the workpiece W is supported by the elastic member 28, even if the workpiece W is long, the one end W7 of the workpiece W does not swing around greatly and can be moved within the range of elastic deformation of the elastic member 28. , can move in the radial direction of the inner peripheral surface 36. Therefore, even if the workpiece W is supported at three points: the spindle side end support part 14a, the tailstock side end support part 14b, and the intermediate support part 13, misalignment between the three points can be absorbed. By doing so, the amount of displacement in the cutting direction of the grindstone at the grinding point of the workpiece can be reduced, and the grinding accuracy can be improved.

The inner diameter of the inner circumferential surface 36 is set so that the crushing rate of the elastic member 28 is within a range of approximately 1 to 10%. The crushing rate of the elastic member 28 is a value representing how much the elastic member 28 is compressed relative to its diameter. As the crushing rate of the elastic member 28 increases, the rigidity of the elastic member 28 increases and it becomes difficult to deform. When the crushing rate is made larger than the above value, the rigidity of the elastic member 28 increases, so that the three points of the spindle side end support part 14a, the tailstock side end support part 14b, and the intermediate support part 13 are It may not be possible to absorb misalignment between the three points when supported. However, by setting the crushing rate of the elastic member 28 within the above range, the elastic member 28 is kept in a state where it is easily deformed. By keeping the rigidity of the elastic member 28 low, one end W7 of the workpiece W can easily move in the radial direction within the inner circumferential surface 36. By making it easier to move one end W7 of the workpiece W in the radial direction, the amount of displacement in the cutting direction of the grindstone at the grinding point where the grindstone 12 cuts into the workpiece W is reduced. It is preferable that the inner circumferential surface 36 is formed coaxially with the output rotating shaft 7 at least at the position of contact with the elastic member 28 . This is because one end W7 of the workpiece W is restored to the center position of the output rotation shaft 7 by the elastic force of the elastic member 28.

A plurality of through holes 39 are provided in the flange portion 37 . The main shaft side end support part 14a is fastened to the main shaft rotary disk 6 by passing a bolt 41 through the through hole 39. The spindle side end support portion 14a rotates together with the spindle rotary disk 6, and transmits rotational force to the workpiece W while supporting one end W7 of the workpiece W. The tailstock side end support portion 14b is fastened to the tailstock 8 by passing a bolt 41b through the through hole 39b. Further, a center 104 that presses and supports the other end W8 of the workpiece W is provided in the tailstock side end support portion 14b. The tailstock side end support portion 14b supports the other end W8 of the workpiece W via the center 104 without rotating.

As shown in FIG. 2A, the coupling 18 includes a main body-side hub 19 attached to the cylindrical output rotation shaft 7, and a main body-side clamp portion 21 for fastening the output rotation shaft 7 and the main body-side hub 19. , a work-side hub 22 attached to one end W7 of the work W, and a work-side clamp portion 23 for fastening the one end W7 of the work W and the work-side hub 22. The main body side clamp portion 21 is tightened with the bolt 26, and the main body side hub 19 and the output rotating shaft 7 are fastened together. The work-side clamp portion 23 is tightened with the bolt 27, and the work-side hub 22 and one end W7 of the work W are fastened together.

FIG. 2(b) shows the tailstock side end support portion 14b that supports the other end W8 of the work W. The tailstock side end support part 14b has the same structure as the spindle side end support part 14a, except that it supports the other end W8 of the workpiece W via the center 104 without rotating. .

As shown in FIG. 2(a), a spacer 24 is provided between the main body side hub 19 and the workpiece side hub 22 to absorb eccentricity and deflection. The spacer 24 has two pins 25 that are perpendicular to each other. The two pins 25 are each inserted into the main body hub 19 or the workpiece hub 22. The main body side hub 19 and the workpiece side hub 22 can slip in the axial direction of the pin 25 inserted therethrough. Therefore, the coupling 18 can absorb misalignment between the main spindle rotary disk 6 and the workpiece W. Moreover, the main body side hub 19 and the workpiece side hub 22 can rotate about the pin 25 inserted therethrough as a central axis. Therefore, the coupling 18 can also absorb the deviation angle between the main spindle rotary disk 6 and the workpiece W.

The workpiece side hub 22 has a body length portion 29 that is longer than the body side hub 19 in the axial direction. An elastic member holding groove 31, which is an annular groove, is formed on the outer circumferential surface of the long body portion 29. The depth of the elastic member holding groove 31 is set to approximately 50% of the wire diameter of the elastic member 28. The elastic member 28 is held at a predetermined position in the longitudinal direction of the coupling 18 by the elastic member holding groove 31 . The elastic member holding groove 31 has a groove bottom 32 and a pair of side walls 33 and 34 . The diameter of the groove bottom 32 is approximately the same as the inner diameter of the elastic member 28 , and the groove bottom 32 is in contact with the inner diameter portion of the elastic member 28 . Therefore, the elastic member 28 can be pressed against the inner peripheral surface 36 and elastically deformed. The distance between the side walls 33 and 34 is set wider than the wire diameter of the elastic member 28 so that the elastic member 28 can be elastically deformed.

In this embodiment, a commercially available O-ring is used as the elastic member 28. In order to give the crushed O-ring appropriate rigidity, synthetic rubber such as nitrile rubber or silicone rubber is used as the material for the O-ring. Although the description has been made using the spindle side end support part 14a, the tailstock side end support part 14b also has the same structure.

As described above, even if misalignment occurs between the spindle side end support part 14a, the tailstock side end support part 14b, and the intermediate support part 13 that support both ends of the workpiece W, respectively. By moving the spindle side end support part 14a and the tailstock side end support part 14b in a direction perpendicular to the longitudinal direction of the workpiece W, the misalignment can be absorbed. Therefore, even if traverse grinding is performed in which the workpiece W is moved parallel to the grindstone 12 in the longitudinal direction, the workpiece W is not displaced in the cutting direction of the grindstone, so that grinding accuracy can be improved. Note that although a cross joint coupling is used as the coupling 18 described above, the structure is not particularly limited as long as it is a coupling that can absorb misalignment and declination.

The following embodiment differs from the workpiece support apparatus 10 according to the first embodiment in the points described below, and has the same configuration as the workpiece support apparatus 10 according to the first embodiment in other respects. Therefore, detailed explanation will be omitted by using the same reference numerals for the same configurations.

(Second embodiment)
The workpiece support device 20 is shown in FIG. 3(a). A ring portion 43 having a larger diameter than the inner circumferential surface 46 of the housing 45 is attached to the outer circumferential surface of the coupling 42 provided on the workpiece support device 20 . The ring part 43 includes a small diameter part 52 located on the back side of the housing 45, a large diameter part 53 located on the mouth side of the housing 45 and having a larger diameter than the small diameter part 52, and the small diameter part 52 and the large diameter part 53. It has a first inclined surface 44 formed between. The first inclined surface 44 is inclined at approximately 45 degrees in cross-sectional view. Therefore, the outer peripheral surface of the ring portion 43 has a conical shape. Note that the angle of the inclined surface is not limited to 45 degrees, and may be smaller or larger than 45 degrees.

In the opening 54 of the housing 45, the inner peripheral surface 46 is chamfered to form a second inclined surface 47. The second inclined surface 47 is inclined at approximately 45 degrees in cross-sectional view, and faces the first inclined surface 44 in parallel. For this reason, the opening 54 of the housing 45 has a recessed conical shape.

As will be described later, the ring portion 43 is movable in the axial direction of the coupling 42. Therefore, the first inclined surface 44 and the second inclined surface 47 have a structure that allows them to come into contact with each other. However, the elastic member 28 is arranged between the first inclined surface 44 and the second inclined surface 47. When the first inclined surface 44 approaches the second inclined surface 47, the elastic member 28 sandwiched between the first inclined surface 44 and the second inclined surface 47 is elastically deformed. Therefore, the first inclined surface 44 and the second inclined surface 47 do not come into contact with each other.

Further, the first inclined surface 44 and the second inclined surface 47 are inclined at approximately 45 degrees with respect to the axis of the coupling 42. Therefore, the elastic member 28 can support the shaft end of the work W connected to the coupling 42 also in the radial direction. Note that the radial direction refers to the radial direction of the workpiece W. Note that the inclination angles of the first inclined surface 44 and the second inclined surface 47 with respect to the axis are not particularly limited, but the axial end of the workpiece W can be radially moved using the first inclined surface 44 and the second inclined surface 47, which are inclined surfaces. In order to provide support in both directions, the inclination angle is preferably in the range of 30 degrees to 60 degrees.

The first inclined surface 44 is provided with an elastic member holding groove 55 which is an annular groove in which the elastic member 28 is held. The elastic member holding groove 55 has a groove bottom 56 and a pair of side walls 57 and 58 . The depth of the elastic member holding groove 55 is set to approximately 50% of the wire diameter of the elastic member 28.

The groove bottom 56 is formed parallel to the second inclined surface 47. The side walls 57 and 58 extend perpendicularly from the groove bottom 56. The interval between the side wall 57 and the side wall 58 is set wider than the wire diameter of the elastic member 28 so that the elastic member 28 can be elastically deformed.

The elastic member 28 is held at a predetermined position on the first inclined surface 44 by the elastic member holding groove 55 . Note that the method of holding the elastic member 28 is not particularly limited. The elastic member 28 may be directly bonded onto the first inclined surface 44 or the second inclined surface 47.

As shown in FIG. 3(b), the coupling 42 and the ring portion 43 are provided with a moving portion 48 for moving the ring portion 43 in the longitudinal direction of the coupling 42. As shown in FIG. The moving portion 48 includes a male threaded portion 49 formed on a portion of the outer circumferential surface of the coupling 42 and a female threaded portion 51 formed on the inner circumferential surface of the ring portion 43 . By rotating the ring part 43 with the female threaded part 51 of the ring part 43 screwed into the male threaded part 49 of the coupling 42, the ring part 43 can be moved back and forth in the axial direction of the coupling 42.

Since the first inclined surface 44 can be moved back and forth in the axial direction, the distance between the first inclined surface 44 and the second inclined surface 47 can be adjusted by the moving part 48. By adjusting the distance between the first inclined surface 44 and the second inclined surface 47, the crushing rate of the elastic member 28 sandwiched between the first inclined surface 44 and the second inclined surface 47 can be adjusted. Although the description has been made using the spindle side end support part 45a, the tailstock side end support part (not shown) also has the same structure.

(Third embodiment)
FIG. 4A shows a workpiece support device 30 of a grinding machine that rotatably supports a midway position of a workpiece W and grinds the outer circumferential surface of the workpiece W with a grindstone 12. The midway position of the workpiece W refers to the position where the grindstone 12 cuts into the workpiece W. The workpiece support device 30 prevents the workpiece W from moving in the cutting direction of the grindstone when the grindstone 12 cuts into the workpiece W.

As shown in FIG. 4(b), the workpiece support device 30 includes an L-shaped swing portion 59, a shaft portion 61 that rotatably supports the swing portion 59 on the main body of the workpiece support device 30, and a swing portion. 59 to the workpiece W, a plurality of rods 72 that support the workpiece W from below and are arranged parallel to the workpiece W, and a lower support section 69 on which the rods 72 are placed. ing.

The swing section 59 can rotate around the shaft section 61. To remove the workpiece W, loosen the screw part 62, rotate the swing part 59 clockwise in FIG. 4(b), and remove the workpiece W from the rod 72. When processing the work W, the swing section 59 is rotated counterclockwise and the screw section 62 is tightened to press the work W on the rod 72.

An upper support plate 67 is provided at the end of the swing section 59. As shown in FIG. 5(a), the upper support plate 67 has a flat portion 68 that comes into contact with the workpiece W. As shown in FIG. The plane portion 68 is in point contact with the workpiece W at a first support point 75 . The first support point 75 is located on a vertical line passing through the rotation center WO of the workpiece W.

The threaded portion 62 is provided with a male threaded portion 63, a flange portion 64 that presses the upper support plate 67, and a rotation lever 65 that rotates the male threaded portion 63. The male threaded portion 63 passes through a long hole 66 formed in the upper support plate 67 and is screwed into the upper part of the main body of the workpiece support device 30 . By rotating the rotary lever 65 in the fastening direction, the flange portion 64 presses the upper support plate 67 downward. The workpiece W is clamped by the upper support plate 67 and the rod 72 which are pressed downward.

The work W can be rotated while being clamped to the work support device 30 by the rotational force output from the output rotation shaft 7. The clamping force of the workpiece W by the threaded portion 62 increases or decreases depending on the tightening force of the threaded portion 62. The clamping force is adjusted in consideration of the rotational force output from the output rotating shaft 7 so that the workpiece W can be rotated. The upper support plate 67 is made of steel, and its hardness is increased by hardening. The upper support plate 67 can also have a flat portion 68, which is a contact surface with the workpiece W, grounded to reduce frictional resistance. Further, the upper support plate 67 may be made of carbide to improve wear resistance and reduce the coefficient of friction with the workpiece W made of steel.

The rod 72 includes a lower first rod 73 and a lower second rod 74, which are arranged on both sides of a vertical line V1 passing through the axis of the workpiece. The lower first rod 73 is located on the side opposite to the grindstone of the vertical line V1 passing through the rotation center WO of the workpiece W. The lower first rod 73 has a cylindrical shape with a diameter of several millimeters to more than ten millimeters. In this embodiment, the length of the lower first rod 73 is 50 mm to 60 mm. Note that the size of the rod 72 is not particularly limited, and other diameters and lengths may be used.

The lower first rod 73 is in point contact with the workpiece W at a second support point 76 . The second support point 76 is located below the rotation center WO of the workpiece W and on the opposite side of the grindstone of the vertical line V1 passing through the rotation center WO of the workpiece W. In this way, the lower first rod 73 supports the workpiece W at the second support point 76 that is located downward from the grindstone cutting direction Wt.

Similarly, the lower second rod 74 is in point contact with the workpiece W at a third support point 77. The third support point 77 is located below the rotation center WO of the work W and on the grindstone side of the vertical line V1 passing through the rotation center WO of the work W. The first lower rod 73 and the second lower rod 74 are arranged at symmetrical positions with respect to the vertical line V1, have the same diameter, and are arranged in parallel.

In this way, the workpiece support device 30 supports the outer peripheral surface of the workpiece W at three points in the radial direction, and the workpiece W is supported up and down by the lower first rod 73, the lower second rod 74, and the upper support plate 67. Supported from the direction. Therefore, if there is a shape error in the outer peripheral surface of the workpiece W, the workpiece W is displaced in the direction of the arrow 78, so that the displacement in the grindstone cutting direction Wt can be reduced. By reducing the displacement of the workpiece W in the grindstone cutting direction Wt, it is possible to prevent the cross-sectional shape and cross-sectional dimensions of the workpiece after grinding from changing in some places in the longitudinal direction of the workpiece, thereby improving the grinding accuracy of the workpiece W. will improve.

On the other hand, as shown in the conventional example of FIG. is displaced in the cutting direction Wt of the grindstone, so that the grinding accuracy of the workpiece W deteriorates.

As shown in FIG. 5(b), the lower support portion 69 is provided with a support position variable portion 79 that allows the support position of the work W to be arbitrarily selected. The support position variable portion 79 is composed of an upper surface portion 71 of the lower support portion 69 facing the workpiece side, and a plurality of groove portions 81 formed in the upper surface portion 71 and parallel to the longitudinal direction of the workpiece W.

The upper surface portion 71 is formed horizontally with a constant distance from the outer peripheral portion of the workpiece W. A rod 82 can be placed between the upper surface portion 71 and the workpiece W. The groove portion 81 has a plurality of V-shaped grooves each having a V-shaped cross section. In FIG. 5(b), a rod 82 having a smaller diameter than the rod 72 is arranged inside the rod 72. In this way, in the variable support position section 79, the rod can be placed in any V-shaped groove of the groove section 81. Note that the rod 82 may be placed in the groove 81 or may be detachably fixed to the groove 81 by screws (not shown) or the like.

The rod 82 includes a lower third rod 83 and a lower fourth rod 84, which are arranged on both sides of a vertical line V1 passing through the axis of the workpiece. The center position of the workpiece W is set to be the same whether the rod 72 or the rod 82 is used. When the lower third rod 83 and the lower fourth rod 84 are used, even if there is a shape error in the outer circumference of the workpiece W, the displacement direction is in the direction of the arrow 85, which is closer to the vertical line V1. Therefore, compared to the case where the grinding wheel is supported by the rod 72, displacement in the cutting direction of the grindstone is further reduced, and grinding accuracy can be improved.

As shown in FIG. 5A, when the workpiece W is supported by the rod 72, the support depth of the workpiece W by the rod 72 is Z1. On the other hand, as shown in FIG. 5(b), when the workpiece W is supported by the rod 82, the support depth of the workpiece W by the rod 82 is Z2. When processing the workpiece W, during rough processing where high grinding accuracy is not required, the amount of cutting into the workpiece W by the grindstone 12 is large, and the force with which the workpiece W is pushed by the grindstone 12 in the cutting direction of the grindstone is large. For this reason, it is preferable to support the rod 72 at the support depth Z1. This is because the workpiece W can be firmly held, making it possible to increase the amount of cut into the workpiece W by the grinding wheel 12, thereby shortening the machining time. When processing the workpiece W, during finishing processing which requires high grinding accuracy, the amount of cut into the workpiece W by the grindstone 12 is small, and the force with which the workpiece W is pushed by the grindstone 12 in the cutting direction of the grindstone is small. Therefore, it becomes possible to support the rod 82 at the support depth Z2. As described above, when the workpiece W is supported by the rod 82, it is possible to improve the machining accuracy more than when the workpiece W is supported by the rod 72.

(Fourth embodiment)
As shown in FIG. 6, the workpiece support device 40 includes a support position variable portion 89 that allows the rod 92 to be placed at any position. The support position variable portion 89 is provided with an upper surface portion 88 formed in an arcuate concave shape and a plurality of groove portions 91 formed in the upper surface portion 88 and parallel to the longitudinal direction of the workpiece W.

The upper surface portion 88 is formed concentrically with the workpiece W with a constant interval from the outer circumference of the workpiece W. A rod 92 can be placed between the upper surface portion 88 and the workpiece W.

The groove portion 91 has a V-shaped cross section. The groove portion 91 is open toward the rotation center WO of the work W, and the center line Vcl of the V-shaped groove is set to pass through the rotation center WO of the work W. By forming V-shaped grooves of the same shape in the upper surface portion 88, the support position of the workpiece W can be changed using the rods 92 having the same diameter.

(Fifth embodiment)
As shown in FIG. 7, the workpiece support device 50 includes a support position variable portion 80 that allows the rod 103 to be placed at any position. The variable support position section 80 is provided with a lower support section 94 in which an upper surface section 95 facing the workpiece side is formed into an arcuate concave shape, and a cage 96 placed on top of the upper surface section 95 .

A protrusion 97 is formed on the lower support portion 94 to restrict movement of the cage 96 in the circumferential direction of the workpiece W. As shown in FIG. 8, the cage 96 includes an outer circumferential surface 98 that contacts the upper surface portion 95, an inner circumferential surface 99 that is open to the work W side, an abutting surface 101 that abuts the protrusion 97, and a rod 103. A holding portion 102 in the form of a long hole is provided in which the holding portion 102 is held.

The outer peripheral surface 98 is formed to have the same curvature as the upper surface portion 95 . Therefore, the cage 96 is placed so as to overlap the upper surface portion 95 without any gap. The inner circumferential surface 99 is set to have a distance from the outer circumferential surface of the workpiece W, and the inner circumferential surface 99 does not come into contact with the outer circumferential surface of the workpiece W.

The contact surface 101 prevents the cage 96 from moving in the circumferential direction of the workpiece W by contacting the protrusion 97 . The height of the contact surface 101 is formed to be approximately the same as the height of the protrusion 97 .

The holding portion 102 is formed parallel to the longitudinal direction of the workpiece W. The elongated hole-shaped holding portion 102 is formed to have a length slightly longer than the rod 103 and a width slightly wider than the rod 103. Therefore, the rod 103 can rotate within the holding part 102. Further, the holding portion 102 can also be formed to have substantially the same length and width as the rod 103. In this case, the rod 103 remains at a fixed location and supports the workpiece W without rotating.

By using the support position variable portion 80 using the cage 96, it is not necessary to process the V-groove on the upper surface portion 95 of the lower support portion 94. Moreover, the rod 103 can be placed in any holding part 102 among the plurality of holding parts 102 according to the processing conditions of the workpiece W. Furthermore, by preparing a plurality of cages of different sizes, rods of different sizes can be used, and workpieces W of various diameters can be processed.

(Sixth embodiment)
The workpiece support device 30 of the third embodiment shown in FIG. 5 can also be used together with the workpiece support device 10 or the workpiece support device 20 shown in FIGS. 2 and 3. Even if misalignment occurs between the spindle side end support part 14a, the tailstock side end support part 14b, and the workpiece support device 30 that support both ends of the work W, the spindle side end By moving the support portion 14a and the tailstock side end support portion 14b in a direction perpendicular to the longitudinal direction of the workpiece W, the misalignment can be absorbed. Furthermore, even if there is a shape error in the outer circumference of the workpiece W, displacement in the cutting direction of the grindstone is reduced, and grinding accuracy can be improved.

(Seventh embodiment)
The workpiece support device 40 of the fourth embodiment shown in FIG. 6 can also be used together with the workpiece support device 10 or the workpiece support device 20 shown in FIGS. 2 and 3. Even if misalignment occurs between the spindle side end support part 14a, the tailstock side end support part 14b, and the workpiece support device 40 that support both ends of the workpiece W, the spindle side end By moving the support portion 14a and the tailstock side end support portion 14b in a direction perpendicular to the longitudinal direction of the workpiece W, the misalignment can be absorbed. Furthermore, the support position of the workpiece W can be changed using rods having the same diameter.

(Eighth embodiment)
The workpiece support device 50 of the fifth embodiment shown in FIG. 7 can also be used together with the workpiece support device 10 or the workpiece support device 20 shown in FIGS. 2 and 3. Even if misalignment occurs between the spindle side end support part 14a, the tailstock side end support part 14b, and the workpiece support device 50 that support both ends of the workpiece W, the spindle side end By moving the support portion 14a and the tailstock side end support portion 14b in a direction perpendicular to the longitudinal direction of the workpiece W, the misalignment can be absorbed. Furthermore, it is possible to process workpieces W of various diameters using rods of different sizes.

1 Screw grinding machine 2 Floor surface 3 Bed 4 Table 5 Headstock 6 Spindle rotary disk 7 Output rotating shaft 8 Tailstock 9 Shaft body 10 Work support device 11 Grinding wheel head 12 Grinding wheel 13 Intermediate support section 14 End support section 14a Main spindle side End support portion 14b Tailstock side end support portion 17 Floating portion 18 Coupling 19 Main body side hub 20 Work support device 21 Main body side clamp portion 22 Work side hub 23 Work side clamp portion 24 Spacer 25 Pin 26 Bolt 27 Bolt 28 Elastic member 29 Long body portion 30 Work support device 31 Elastic member holding groove 32 Groove bottom 33 Side wall 34 Side wall 35 Housing 36 Inner peripheral surface 37 Flange portion 38 Cylindrical portion 39 Through hole 39b Through hole 40 Work support device 41 Bolt 41b Bolt 42 Cup Ring 43 Ring portion 44 First inclined surface 45 Housing 46 Inner peripheral surface 47 Second inclined surface 48 Moving portion 49 Male threaded portion 50 Work support device 51 Female threaded portion 52 Small diameter portion 53 Large diameter portion 54 Opening portion 55 Elastic member holding groove 56 Groove Bottom 57 Side wall 58 Side wall 59 Swing part 61 Shaft part 62 Thread part 63 Male thread part 64 Flange part 65 Rotating lever 66 Long hole 67 Upper support plate 68 Plane part 69 Lower support part 71 Top part 72 Rod body 73 Lower first rod body 74 Lower second rod 75 First support point 76 Second support point 77 Third support point 78 Arrow 79 Support position variable portion 81 Groove 82 Rod 83 Lower third rod 84 Lower fourth rod 85 Arrow 86 Support part 88 Upper surface part 89 Support position variable part 91 Groove part 92 Rod body 94 Lower support part 95 Upper surface part 96 Cage 97 Projection part 98 Outer circumferential surface 99 Inner circumferential surface 101 Contact surface 102 Holding part 103 Rod body 104 Center v1 Vertical line vcl Center line W Workpiece W7 One end W8 Other end Wt Grindstone cutting direction z1 Support depth z2 Support depth

Claims (13)

A workpiece support device for a grinding machine that rotatably supports both ends and an intermediate position of a long workpiece with a circular cross section, and grinds the outer peripheral surface of the workpiece with a grindstone,
an end support part that rotatably supports both ends of the workpiece;
an intermediate support part that rotatably supports an intermediate position of the work;
a floating part provided on the end support part to move the end of the work in a direction orthogonal to the longitudinal direction of the work;
If there is misalignment between the end support part and the intermediate support part that support both ends of the workpiece, and the workpiece is not supported in a straight line and is bent, the floating part may not be aligned with the longitudinal direction of the workpiece. A workpiece support device that absorbs the misalignment by moving in orthogonal directions. The floating part is
a housing having a cylindrical inner peripheral surface;
a coupling disposed within the housing;
The work supporting device according to claim 1, further comprising an elastic member disposed between an inner circumferential surface of the housing and an outer circumferential surface of the coupling. An annular ring portion is attached to the outer circumferential surface of the coupling, a conical first inclined surface is formed on the outer circumferential surface of the ring portion, and the first inclined surface and the first inclined surface are formed on the inner circumferential surface of the housing. Opposing second inclined surfaces are formed, the elastic member is disposed between the first inclined surface and the second inclined surface, and a moving section for moving the ring section in the longitudinal direction of the coupling. The workpiece support device according to claim 2, wherein the work supporting device is provided so that the distance between the first inclined surface and the second inclined surface can be adjusted by the moving section. 4. The work supporting device according to claim 3, wherein the moving portion includes a male threaded portion formed on the outer circumferential surface of the coupling and a female threaded portion formed on the inner circumferential surface of the ring portion. A workpiece support device for a grinding machine that rotatably supports an intermediate position of a long workpiece having a circular cross section and grinds the outer peripheral surface of the workpiece with a grindstone, the workpiece support device comprising:
The outer peripheral surface of the workpiece is supported at three points from the radial direction,
Of the three points, the first support point is located above the axis of the workpiece,
The second and third support points are located below the axis of the workpiece and on both sides of a vertical line passing through the axis of the workpiece,
A workpiece support device including a support position variable part that makes the positions of the second support point and the third support point variable. an upper support plate having a plane including the first support point;
a lower first rod disposed parallel to the workpiece W having a curved surface including the second support point;
a lower second rod disposed parallel to the workpiece W having a curved surface including the third support point;
The workpiece support device according to claim 5, wherein the first support point is located on a vertical line passing through the axis of the workpiece. The support position variable part is
a lower support part that supports the lower first rod and the lower second rod;
an upper surface portion of the lower support portion facing the workpiece;
a plurality of grooves parallel to the longitudinal direction of the workpiece formed on the top surface;
It is composed of
The workpiece support device according to claim 6, wherein the first lower rod and the second lower rod can be arranged in any groove among the plurality of grooves. The work supporting device according to claim 7, wherein the groove portion is formed as a V-shaped groove having a V-shaped cross section. The workpiece support device according to claim 8, wherein the upper surface portion is formed in a concave shape of an arc. The support position variable part is configured by a cage that is placed on the upper surface of the lower support part facing the workpiece and has a plurality of elongated holes parallel to the longitudinal direction of the workpiece, and the cage has a plurality of elongated holes parallel to the longitudinal direction of the workpiece. 8. The workpiece support device according to claim 7 , wherein the lower second rod can be disposed in any of the plurality of long holes, and the upper surface portion is formed in a concave shape of an arc. The workpiece support device according to any one of claims 1 to 4, wherein the intermediate support portion is the workpiece support device according to claim 8. The workpiece support device according to any one of claims 1 to 4, wherein the intermediate support portion is the workpiece support device according to claim 9. The workpiece support device according to any one of claims 1 to 4, wherein the intermediate support portion is the workpiece support device according to claim 10.

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