JP2008030195A - Grinding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To spherically grind an end face of a conical trapezoidal workpiece at the larger diameter side accurately without any shear droop. <P>SOLUTION: Workpieces 11 are held between upper and lower rotating tables 12 and 13 to receive outward extrusion force, are rotated around a center of an axis, and are fed in a circumferential direction of the upper and lower table 12 and 13. The device is provided with workpiece guiding members without a rotating drive mechanism for arranging the workpieces 11 plurally between the rotating tables 12 and 13 in the circumferential direction. A guiding mechanism 20 is provided at an outer circumference of the upper and lower rotating tables 12 and 13 to form a curvature corresponding to the spherical radius of the larger diameter end faces 34 of the workpieces 11. The guiding mechanism is formed in a feed direction of the workpieces 11 and guides by partially contacting the end faces 34. Irrotational grinding wheels 17A-17D are pressed by air cylinders 50 to contact other ends of the end faces 34 of the larger diameter side of the workpieces 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a grinding device, and more particularly to a grinding device for grinding a large-diameter end face of a truncated cone workpiece into a spherical shape.

  A tapered roller 2 of a tapered roller bearing 1 shown in FIG. 8 is given as a truncated cone workpiece whose end surface on the large diameter side is to be ground into a spherical shape. Reference numeral 3 denotes a spherical surface which contacts the flange 5 of the inner ring 4. 6 is an outer ring.

The side surface of the flange 5 of the inner ring 4 is formed in a concave spherical shape corresponding to the spherical surface 3 of the tapered roller 2. Here, if the radius of the spherical surface 3 of the tapered roller 2 is R and the radius of the concave spherical surface of the flange 5 is R0,
R0> R
It is necessary to establish the relationship. That is, the radius of the spherical surface 3 of the tapered roller 2 must be smaller than the radius of the concave spherical surface of the flange 5. When the radius of the spherical surface 3 of the tapered roller 2 is greater than or equal to the radius of the concave spherical surface of the flange 5, both of them come into contact with each other, and large wear is likely to occur.

  In order to improve the performance of the bearing, the radius R of the spherical surface 3 of the tapered roller 2 needs to be smaller than the radius R0 of the concave spherical surface of the flange 5 as described above, but a value as close as possible to this radius R0. It is necessary to be. In order to improve the performance of the bearing, the spherical surface 3 needs to be finished in a state where the surface roughness is suppressed as much as possible. For example, it is necessary to perform super finishing or the like.

  For this reason, conventionally, it has been attempted to make R 80% or more of R0 by grinding and to suppress the surface roughness. For example, a finishing grindstone is disposed along a C-shaped arcuate track, and a tapered roller is moved along the arcuate track so that the end surface thereof is spherically processed with the above-described accuracy.

  However, the grinding accuracy cannot be improved only by processing in this way. In other words, when the entire spherical surface of the tapered roller is viewed, the radius R can be set to 80% or more of R0 as described above. A so-called sagging that has fallen has occurred, and this has caused a decrease in the performance of the bearing. Further, in the conventional grinding process, as described above, the radius R of the spherical surface 3 of the tapered roller 2 can be machined only to about 80% of the radius R0 of the concave spherical surface of the flange 5, and it is difficult to achieve higher accuracy. . However, there is still room for improvement because the radius R of the spherical surface 3 of the tapered roller 2 is as close as possible to the radius R0 of the concave spherical surface of the flange 5 because it contributes to improving the performance of the bearing.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve such problems and to grind the end surface on the large diameter side of a truncated cone workpiece into a spherical shape with high accuracy without causing sagging. To do.

To achieve this object, the present invention provides an apparatus for grinding a large-diameter end face of a frustoconical workpiece into a spherical shape, a lower rotary table rotated by a first drive device, and a second drive. An upper rotary table that is rotated by the apparatus and moved in the axial direction is arranged in a vertically overlapping manner, and the workpiece is placed between the lower rotary table and the upper rotary table with the large diameter side facing outward. A plurality of circumferentially arranged work guide members having no rotation drive device are provided, and are sandwiched between the lower rotary table and the upper rotary table so as to be rotated around the axis while receiving an outward pushing force. And a guide device for positioning in contact with a part of the end surface on the large diameter side of the workpiece to which feed is given in the circumferential direction of the upper and lower rotary tables, and the work positioned by the guide device A non-rotating grinding wheel that grinds the other part of the end surface on the large-diameter side on the outer peripheral side of the upper and lower rotary tables, and the guide device has a curvature corresponding to the radius of the spherical surface of the end surface of the workpiece And the non-rotating grinding wheel is formed in the workpiece feed direction and is pressed by an air cylinder to form the workpiece. The other end face on the large diameter side is in contact with a force weaker than the outward pushing force applied to the workpiece from the upper and lower rotary tables.
According to the present invention, in the above, the lower rotary table is connected to the hollow first drive shaft, and the upper rotary table is connected to the second drive shaft disposed inside the first drive shaft. It is preferable to include an axial movement device that relatively moves the table and the upper rotary table in the axial direction and a device that pressurizes the upper rotary table toward the lower rotary table.

According to the present invention, in the above, it is preferable that the axial movement device uses a spline mechanism.
According to the present invention, in the above, it is preferable that a plurality of non-rotating grinding wheels whose particle size is gradually reduced are provided along the circumferential direction of the upper and lower rotary tables.

  Further, according to the present invention, in the above, the rotary grinding wheel for machining the end face on the large diameter side of the workpiece is provided on the upper side than the non-rotating grinding wheel along the circumferential direction of the upper and lower rotary tables. The work piece guide member is preferably provided with a dresser for dressing the rotary grinding wheel.

  According to the present invention, the guide device is provided on the outer peripheral side of the upper and lower rotary tables so as to be in contact with a part of the end surface on the large diameter side of the truncated cone-shaped workpiece, and the other end surface on the large diameter side of the workpiece Since the non-rotating grinding wheel in contact with the portion is provided, the workpiece can be accurately positioned by the guide device and the end surface on the large diameter side can be ground by the non-rotating grinding wheel. Can be ground to a spherical shape with high accuracy.

  FIG. 1 is a plan view showing a schematic configuration of a grinding apparatus according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view thereof. Here, reference numeral 11 denotes a workpiece, such as the tapered roller of the tapered roller bearing described above. Reference numerals 12 and 13 denote upper and lower rotary tables, which are arranged so as to be rotatable around the same central axis while being overlapped with each other. The workpiece 11 is arranged in the radial direction of the rotary tables 12 and 13 so that the end face on the large diameter side is located on the outer peripheral side by being sandwiched between the peripheral edges of the upper and lower rotary tables 12 and 13. Yes.

  In FIG. 1, 14 is a supply part for the workpiece 11, and 15 is its discharge part. The workpiece 11 is sandwiched between the peripheral edges of the upper and lower rotary tables 12 and 13 and is held in a C-shaped circle from the supply unit 14 toward the discharge unit 15 according to the rotation of the rotary tables 12 and 13. While being moved along the arcuate path, it undergoes a grinding process. Along with this path, a rotary finishing grindstone 16 composed of a cup grindstone and a plurality of non-rotating superfinishing grindstones 17A, 17B, 17C, 17D are arranged. An arc-shaped first guide device 18 is provided between the supply unit 14 and the finishing grindstone 16 to contact the end surface 34 on the large diameter side of the workpiece 11 and guide the end surface 34. A similar second guide device 19 is provided between the finishing grindstone 16 and the first superfinishing grindstone 17A. A third guide device 20 is provided from the first superfinishing grindstone 17A to the last superfinishing grindstone 17D. A fourth guide device 21 is provided between the last superfinishing grindstone 17 </ b> D and the discharge unit 15.

  Next, the rotational drive mechanism of the upper and lower rotary tables 12 and 13 will be described. In FIG. 2, reference numeral 24 denotes a first motor, which is attached to a machine base 25 of a grinding apparatus and has a hollow rotating shaft 26 in the vertical direction. The lower rotary table 13 is coupled to the upper end portion of the hollow rotary shaft 26 so as to be driven to rotate. A solid rotary shaft 27 is supported inside the hollow rotary shaft 26 so as to be rotatable concentrically. The rotary shaft 27 is provided in the vertical direction from a position protruding downward from the lower end of the hollow rotary shaft 26 to a position protruding upward from the upper end of the hollow rotary shaft 26. And the 2nd motor 28 is connected to the lower end part, and the spline shaft 29 is formed in the upper end part. The upper rotary table 12 has a spline hole portion 30 that fits into the spline shaft 29, so that the upper rotary table 12 can move up and down within a range where the spline shaft 29 and the spline hole portion 30 fit together. In this state, the rotary shaft 27 is connected to the rotary shaft 27 and is driven to rotate.

  An air cylinder (not shown) is provided above the upper rotary table 12, and the telescopic operation shaft 31 is disposed so as to protrude downward. The upper rotary table 12 is connected to the lower end of the telescopic operation shaft 31. Accordingly, the upper rotary table 12 is guided by the spline shaft 29 and the spline hole 30 so that the downward pressure applied to the lower rotary table 13 is acted on by the operating shaft 31 of the air cylinder. It is configured.

  As shown in FIGS. 2 to 4, a disc-shaped workpiece guide member 32 is disposed between the upper rotary table 12 and the lower rotary table 13 in a state where the central axes of the rotary tables 12 and 13 coincide with each other. Has been. The workpiece guide member 32 is arranged on the outer peripheral side of the rotary shaft 27 and is not connected to a rotary drive device such as a motor. The workpiece guide member 32 has a plurality of recesses 33 in the circumferential direction, and each workpiece 11 is placed in each recess 33 so that the end surface 34 on the large diameter side is positioned on the outer periphery side as described above. 12 and 13 can be accommodated in a state of being horizontally arranged in the radial direction. The disk-shaped workpiece guide member 32 is formed thinner than the diameter of the end portion on the small diameter side of the truncated cone-shaped workpiece 11. That is, when the workpiece 11 is accommodated in the horizontal direction, an upper portion and a lower portion of the workpiece 11 are formed so as to protrude above and below the upper and lower surfaces of the workpiece guide member 32. Yes.

  As shown in FIG. 4, the workpiece guide member 32 is provided with a dresser 35 at an appropriate position avoiding the recess 33. The dresser 35 can dress the finishing grindstone 16 as the rotary tables 12 and 13 rotate.

  As shown in detail in FIG. 3 and FIG. 5, the workpiece 11 is sandwiched between the rotary tables 12 and 13 at the peripheral portions of the upper and lower rotary tables 12 and 13 for the purpose of holding the workpiece 11. The inclined surfaces 37 and 38 corresponding to the inclination of the eleven frustoconical tapered surfaces 36 are formed in the circumferential direction of the tables 12 and 13. Since the workpiece guide member 32 is formed thinner than the workpiece 11 as described above, the inclined surfaces 37 and 38 hold only the workpiece 11, and the guide member 32 is sandwiched between the inclined surfaces 37 and 38. There is nothing.

  For this reason, when the workpiece 11 is housed in the recess 33 of the workpiece guide member 32 and the upper rotating table 12 is pressurized toward the lower rotating table 13 by the operating shaft 31 of the cylinder device, as shown in FIG. On the basis of the applied pressure 39, the inclined surfaces 37 and 38 and the tapered surface 36 act to generate a pushing force 40 for pushing the workpiece 11 outward in the radial direction of the rotary tables 12 and 13.

  In this way, the workpiece 11 receives the pushing force 40, but is received in contact with the guide devices 18 to 21 with its end surface 34 slightly protruding in the radial direction from the rotary tables 12, 13, so that the rotary table 12 is received. , 13 are positioned at predetermined positions along the radial direction.

  As described above, the upper rotary table 12 and the lower rotary table 13 are connected to the first and second motors 24 and 28, respectively. With such a configuration, the upper and lower rotary tables 12 and 13 can be driven to rotate. The feed can be given to the workpiece 11. In addition, since the upper and lower rotary tables 12 and 13 are connected to separate motors 24 and 28, the inclined surfaces 37 of the upper rotary table 12 and the lower rotary table 12 are rotated downward by making the motors 24 and 28 have different speeds. The workpiece 11 sandwiched between the inclined surface 38 of the table 13 can be rotated around its axis. The rotational speed of the workpiece 11 can be changed depending on the rotational speed difference between the two rotary tables 12 and 13, and, for example, by reversing the rotational direction of the upper and lower rotary tables 12 and 13 as shown in FIG. High speed rotation can be imparted to the workpiece.

  When the rotation directions of the upper and lower rotary tables 12 and 13 are reversed as described above, the circumferential feed of the tables 12 and 13 can be given to the workpiece 11 based on the difference in the rotation speed. For example, when the upper rotary table 12 is rotated clockwise at 150 rpm and the lower rotary table 13 is rotated counterclockwise at 140 rpm, the workpiece 11 and its guide member 32 are clocked at 5 rpm which is half of the difference between the two. Feed is given in the direction. For example, when the upper rotary table 12 is rotated clockwise at 155 rpm and the lower rotary table 13 is rotated counterclockwise at 150 rpm, the workpiece 11 and its guide member 32 are half of the difference between them. Feed is applied clockwise at 5 rpm. The number of rotations at which the upper rotary table 12 and the lower rotary table 13 are rotated to give the feed to the workpiece 11 and its guide member 32 is based on various conditions such as the diameter of the workpiece. Can be decided.

  Next, the 3rd and 4th guide apparatuses 20 and 21 and superfinishing grindstones 17A-17D are explained. As shown in FIGS. 1 and 6, the third guide device 20 is formed in a C shape with a length extending over a plurality of superfinishing wheels 17 </ b> A to 17 </ b> D, and slightly from the upper and lower rotary tables 12 and 13 in the radial direction. And an inner peripheral side contact surface 42 that can come into contact with the end surface 34 of the workpiece 11 projecting. The third guide device 20 is formed of a hard and wear-resistant material, and the inner peripheral contact surface 42 has a spherical radius of the end surface 34 of the workpiece 11 in plan view. It is formed with a highly accurate curvature corresponding to Further, it is provided in a state of being positioned at a predetermined position with extremely high accuracy. In the third guide device 20, as shown in FIG. 6, the inner peripheral contact surface 42 is in contact with the lower half portion of the end surface 34 of the workpiece 11 supported in the horizontal direction by the upper and lower rotary tables 12, 13. It is configured as follows. That is, the end surface 34 of the workpiece 11 is guided while the lower half portion thereof is in contact with the inner peripheral side contact surface 42 of the third guide device 20, and the upper half portion thereof is the third portion. The guide device 20 protrudes from the inner peripheral contact surface 42 and is exposed. In addition, a concave thin portion 41 is formed in the center of the end surface 34 of the workpiece 11, and actually, an annular portion of the end surface 34 excluding the thin portion 41 is ground.

The superfinishing grindstones 17A to 17D are each configured to have a grindstone 44 inside the holder 43. The grindstone 44 is located at a position avoiding the third guide device 20 by the action of the air cylinder 50, that is, the above-mentioned in the workpiece 11. It is comprised so that it may be pressed by the part except the meat thinning part 41 in the end surface 34 in the upper half part. The grindstone 44 is configured to have an inner peripheral surface with a curvature that exactly corresponds to the finishing dimension of the radius of the spherical surface of the end surface 34, and as it goes from the upper side to the lower side along the feed direction of the workpiece 11. Each of the superfinishing grindstones 17A to 17D is configured such that the particle size gradually becomes finer and the machining roughness is reduced. The grindstone 44 is configured to have a predetermined length, that is, a width dimension along the circumferential direction of the tables 12 and 13, and is configured so that an appropriate number of workpieces 11 always exist within the width.
When the pressing force 40 applied to the workpiece 11 by the rotary tables 12 and 13 is F0 and the pressing force 45 applied to the end surface 34 by the grindstone 44 based on the force of the air cylinder 50 is F, the end surface 34 of the workpiece 11 is set. In order not to leave the inner peripheral side contact surface 42 for the purpose of being correctly guided by the third guide device 20,
F0> F
It is necessary to be.

  The difference between F0 and F becomes a force 46 by which the workpiece 11 presses the inner peripheral side contact surface 42 of the third guide device 20. When this force 46 is ΔF, the occurrence of wear on the inner peripheral contact surface 42 of the third guide device 20 can be reduced by making ΔF as small as possible. For this purpose, the pressing force 45 applied to the end face 34 by the grindstone 44, that is, F, has a value necessary for performing a required grinding process. By adjusting the pressure, the pushing force 40 applied to the workpiece 11, that is, F 0 is made as close to F as possible.

  As shown in FIG. 1 and FIG. 7, the rotary finishing grindstone 16 composed of a cup grindstone is offset in a tangential direction toward the upper side in the feed direction of the workpiece 11 with respect to the upper and lower rotary tables 12 and 13. Is provided. That is, 47 is a center line of the rotary tables 12 and 13, 48 is a rotation center of the finishing grindstone 16, and a tangential offset 49 of the rotary tables 12 and 13 exists between them. .

  By doing so, as shown in the drawing, the movement trajectory of the end surface 34 of the workpiece 11 based on the rotation of the tables 12 and 13 is directed to the cup grindstone from the upper side to the lower side along the feeding direction of the workpiece 11. The rotary finishing grindstone 16 constructed as described above can be formed so as to approach gradually. Therefore, the finishing grindstone 16 can be gradually cut into the end surface 34 of the workpiece 11, and grinding can be performed without difficulty.

  In such a configuration, the workpiece 11 fed into the supply unit 14 of the apparatus is accommodated in the concave portion 33 of the workpiece guide member 32, and the end surface 34 on the large diameter side is radial from the periphery of the rotary tables 12, 13. Is sandwiched between the upper and lower rotary tables 12 and 13 so as to protrude outward. Then, as the rotary tables 12 and 13 rotate, the workpiece 11 is fed in the circumferential direction of the tables 12 and 13 while being rotated about its axis.

  The workpiece 11 is first fed into the rotary finishing grindstone 16 with its end face 34 contacting the first guide device 18 and receiving guidance. In the finishing grindstone 16, the end face is finished. The workpiece 11 that has been finished is then guided by the second guide device 19 and fed into the first non-rotating super-finishing grindstone 17A.

  At this time, the workpiece 11 is passed from the second guide device 19 to the third guide device 20 and rotated around the axis in a state where the workpiece 11 is positioned very accurately by the third guide device 20 as described above. In this way, it is sent in the circumferential direction of the tables 12 and 13. In this state, the end face 34 is first superfinished by the first stage superfinishing grindstone 17A. Then, in the same manner, it is processed by super-finishing grindstones 17B, 17C, and 17D on and after the next stage where the particle size gradually becomes finer, and finally finished to have a desired surface roughness. Further, by being processed by the non-rotating super-finishing grindstones 17A to 17D in a state of being in contact with the inner peripheral side contact surface 42 of the third guide device 20 configured extremely precisely as described above, The spherical surface has a predetermined radius, and finish processing can be performed with extremely high accuracy without causing a so-called sagging in the edge portion of the spherical surface.

  For this reason, when the workpiece 11 is a tapered roller bearing, for example, the radius of the spherical surface can be processed to be 95% or more of the radius of the concave spherical surface of the flange of the inner ring of the bearing.

  Since the workpiece 11 that has been processed is finally guided by the fourth guide device 21 and reaches the discharge unit 15, there is no member that guides the end surface of the discharge unit 15 to suppress the end face, The pushing force 40 pushes out from the turntables 12 and 13 outward in the radial direction and is discharged.

  Since the dresser 35 is provided on the workpiece guide member 32, the finishing grindstone 16 is dressed as the tables 12 and 13 rotate. The dresser 35 is provided at a position that does not interfere with the grindstone 44 of the superfinishing grindstones 17A to 17D, the third guide device 20, and the like.

It is a top view which shows schematic structure of the grinding device of embodiment of this invention. It is a longitudinal cross-sectional view of the grinding apparatus of FIG. It is sectional drawing which shows holding | maintenance operation | work of the workpiece by a rotary table. It is a figure which shows the state in which the workpiece is accommodated in the recessed part of a guide member. It is a perspective view which shows holding | maintenance operation | work of the workpiece by a rotary table. It is a figure which shows the positional relationship of a workpiece, a guide apparatus, and a grindstone. It is a figure which shows arrangement | positioning of a finishing grindstone. It is a figure which shows the tapered roller of the tapered roller bearing as a workpiece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Workpiece 12 Upper rotary table 13 Lower rotary table 16 Finishing grindstone 17A-17D Superfinishing grindstone 18-21 Guide apparatus 24 1st motor 26 Hollow rotating shaft 27 Rotary shaft 28 2nd motor 29 Spline shaft 30 Spline hole part 31 Telescopic operating shaft 32 Workpiece guide member 34 End face 35 Dresser 50 Air cylinder

Claims (5)

An apparatus for grinding a large diameter end face of a truncated cone workpiece into a spherical shape,
The lower rotary table rotated by the first drive device and the upper rotary table rotated by the second drive device and moved in the axial direction are arranged in a state where they are overlapped vertically.
Between the lower rotary table and the upper rotary table, comprising a workpiece guide member that does not have a rotation drive device, the plural workpieces are arranged in the circumferential direction with the large diameter side facing outward,
Large diameter of the work piece that is sandwiched between the lower rotary table and the upper rotary table and is rotated around the axis while receiving an outward pushing force and feed is provided in the circumferential direction of the upper and lower rotary tables. A guide device for positioning in contact with a part of the end surface on the side, and a non-rotating grinding wheel for grinding the other part of the end surface on the large diameter side of the workpiece positioned by the guide device. Prepare on the outer peripheral side than the rotary table,
The guide device is formed with a curvature corresponding to the radius of the spherical surface of the end surface of the workpiece and is formed in the feed direction of the workpiece,
The non-rotating grinding wheel is formed in the direction of feeding the workpiece, and is pressed by an air cylinder so that the non-rotating grinding wheel is machined from the upper and lower rotary tables to the other part of the end surface on the large diameter side of the workpiece. A grinding apparatus characterized by being in contact with a force weaker than an outward pushing force applied to an object. The lower rotary table is connected to a hollow first drive shaft, the upper rotary table is connected to a second drive shaft disposed inside the first drive shaft, and the lower rotary table and the upper rotary table are axially connected. 2. The grinding apparatus according to claim 1, further comprising: an axial movement device that moves relative to the upper rotation table; and a device that pressurizes the upper rotation table toward the lower rotation table. The grinding apparatus according to claim 2, wherein the axial movement device uses a spline mechanism. The grinding apparatus according to any one of claims 1 to 3, wherein a plurality of non-rotating grinding wheels with gradually decreasing grain sizes are provided along the circumferential direction of the upper and lower rotary tables. A rotary grinding wheel that processes the end face on the large diameter side of the workpiece is provided on the upper side of the non-rotating grinding wheel along the circumferential direction of the upper and lower rotary tables, and rotary grinding is performed on the workpiece guide member. The grinding apparatus according to any one of claims 1 to 4, wherein a dresser for dressing the grindstone is provided.

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