US20130213106A1 - Dimple-forming burnishing tool and dimple-forming burnishing method - Google Patents
Dimple-forming burnishing tool and dimple-forming burnishing method Download PDFInfo
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- US20130213106A1 US20130213106A1 US13/774,366 US201313774366A US2013213106A1 US 20130213106 A1 US20130213106 A1 US 20130213106A1 US 201313774366 A US201313774366 A US 201313774366A US 2013213106 A1 US2013213106 A1 US 2013213106A1
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- Prior art keywords
- mandrel
- work surface
- outer peripheral
- balls
- peripheral surface
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B39/00—Burnishing machines or devices, i.e. requiring pressure members for compacting the surface zone; Accessories therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D17/00—Forming single grooves in sheet metal or tubular or hollow articles
- B21D17/04—Forming single grooves in sheet metal or tubular or hollow articles by rolling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B39/00—Burnishing machines or devices, i.e. requiring pressure members for compacting the surface zone; Accessories therefor
- B24B39/02—Burnishing machines or devices, i.e. requiring pressure members for compacting the surface zone; Accessories therefor designed for working internal surfaces of revolution
- B24B39/023—Burnishing machines or devices, i.e. requiring pressure members for compacting the surface zone; Accessories therefor designed for working internal surfaces of revolution the working tool being composed of a plurality of working rolls or balls
Definitions
- the invention relates to a dimple-forming burnishing tool and a dimple-forming burnishing method for forming a dimple on a work surface by contacting a ball with the work surface.
- the surface treatment for forming the dimples on a work surface such as the sliding surface has been known as a dimple-forming by a WPC treatment (fine-particle shot-peening), a dimple-forming by a laser-machining and the like.
- the dimple-forming by the WPC treatment is a surface treatment of shooting fine particles, smaller than those for an ordinary peening, at a high speed to be struck on the work surface for forming dimples.
- the dimple-forming by the laser-machining is a surface treatment of radiating laser beam on the work surface using an exclusive processing machine for forming dimples.
- the burnishing tool includes a cylindrical frame fitted to a mandrel from the outside.
- the cylindrical frame holds rotatably rolling elements to come radially out of or into the outer peripheral surface of the frame.
- the projections, formed on the outer peripheral surface of the mandrel engage rolling elements such as balls.
- the rolling elements vibratingly rotate on the inner peripheral surface of a work as a work surface.
- the WPC treatment requires shooting particles at every surface treatment, which raises machining cost, and is not efficient.
- the laser-machining is difficult to be applied to the work surface of the narrow portion such as a side surface of the groove portion.
- the burnishing tool as described in Patent Document 1 is a tool used for the surface treatment to the inner peripheral surface of a hole formed to a work, and is not applied to the surface treatment to a work surface such as a side surface of the groove portion. If the tool is used on the work surface of the narrow portion such as the side surface of the groove portion, a tool diameter becomes smaller, and the tool is flexed during formation of dimples. This causes difficulty in to forming dimples by secure contacting all of the rolling elements on the work surface.
- the invention is directed to a dimple-forming burnishing tool and a dimple-forming burnishing method which efficiently and securely form dimples to a work surface of a narrow portion such as a side surface of a groove portion.
- a first aspect of the invention provides a dimple-forming burnishing tool.
- the dimple-forming burnishing tool includes a mandrel having an end side fitted and fixed to a processing machine for rotating; and a frame fitted to another side of the mandrel from the outside, and holding balls contacting an outer peripheral surface of the mandrel.
- the balls on the outer peripheral surface contact a work surface with the mandrel and the frame rotated for forming dimples on the work surface.
- the outer peripheral surface has a contact surface with the balls.
- the contact surface is at a side of the outer peripheral surface which is closer to the work surface.
- the contact surface and the work surface have a distance therebetween in a direction normal to the work surface.
- a distance at a side of the mandrel closer to the processing machine and a distance at the opposite side of the mandrel to said side have a distance difference therebetween.
- a diameter of the outer peripheral surface on the mandrel is set in such a way that the distance difference with the mandrel flexed during formation of the dimples becomes smaller than that before flexing of the mandrel.
- the burnishing tool of a smaller diameter enables all of the balls arranged on the outer peripheral surface to be pressed against the work surface with the mandrel flexed.
- This operation forms the dimples of approximately a uniform depth at a predetermined whole region on the work surface of a narrow portion which is a side surface of, for example, a groove portion.
- the dimples are efficiently and securely formed to the work surface of the narrow portion such as a side surface of the groove portion.
- the work surface is formed with very fine and uniform dimples, and keeps a lubricant in the dimples. This prevents a lubricant from running out, and reduces frictional resistance, thereby enhancing the sliding property.
- the dimple-forming burnishing tool is fitted to a generic processing machine (machine tool) such as a machining center, or an NC milling machine for use, and is capable of forming dimples in a shape which is required with ease and at an inexpensive cost.
- a generic processing machine such as a machining center, or an NC milling machine for use
- the mandrel has a first sectional line which is positioned on the outer peripheral surface and at said side of the mandrel closer to the work surface.
- the first sectional line is defined by sectioning the mandrel by a plane which is normal to the work surface and includes an axis of the mandrel.
- the work surface has a second sectional line on the work surface.
- the second sectional line is defined by sectioning the work surface by the plane.
- the first sectional line and the second sectional line have a parallel degree therebetween.
- a diameter of the outer peripheral on the mandrel at the opposite side to a side closer to the processing machine is set to be larger than that at said side close to the processing machine, so that the parallel degree with the mandrel flexed during formation of the dimples becomes smaller than that before flexing of the mandrel.
- the work surface is a plane.
- the sectional line at the side of the outer peripheral surface closer to the work surface is approximately parallel with the sectional line on the work surface. This permits all of the balls arranged on the outer peripheral surface to be pressed against the work surface at a further uniform strength.
- the outer peripheral surface of the mandrel has a side shape in a frustum of a circular cone which diverges toward the opposite side to said side closer to the processing machine.
- the sectional line at a side of the outer peripheral surface closer to the work surface is exactly a curved line, not a straight line.
- a parallel degree between the sectional line at a side of the outer peripheral surface closer to the work surface and the sectional line on the work surface become sufficiently smaller.
- the balls are spaced apart from each other in a peripheral direction of the frame and in a direction parallel with the axis of the frame.
- the frame includes: a frame body fitted to the mandrel from the outside and defining first through-holes for the balls to be fitted thereto, respectively; and a frame cover fitted to the frame body from the outside, having the balls projecting radially outward from the outer peripheral surface of the frame, and defining second through-holes which coincide in position with the first through-holes for preventing the balls from dropping out of the first through-holes, respectively.
- the invention facilitates machining such as formation of holes for holding the balls, thereby enhancing manufacturing operability for the dimple-forming burnishing tool.
- a second aspect of the invention provides a dimple-forming burnishing method which includes contacting the balls on the work surface to form dimples on the work surface using the dimple-forming burnishing tool according to the first aspect of the invention.
- this enables the dimples to be efficiently and securely formed on the work surface of the narrow portion such as a side surface of the groove portion.
- FIG. 1 is a half sectional view which shows a whole structure of a dimple-forming burnishing tool according to an embodiment of the invention.
- FIG. 2 is a general perspective view of the burnishing tool as show in FIG. 1 , which shows an example of working condition.
- FIG. 3 is a schematic view of the front periphery of a mandrel before the mandrel is flexed.
- FIG. 4 is a schematic view of the front periphery of the mandrel with the mandrel flexed during formation of dimples.
- FIG. 5 is a perspective view of the mandrel which schematically shows the front periphery of the mandrel with the mandrel flexed during formation of dimples.
- FIGS. 6A and 6B are views which show the state of dimple-forming by a burnishing tool
- FIG. 6A is a general view as viewed from the position opposed to the work surface
- FIG. 6B is an enlarged view of the dimples formed on the work surface as shown in FIG. 6A .
- FIGS. 7A , 7 B and 7 C are schematic views of a mandrel which is pressed into the work surface with the pressing-into amount varied, FIG. 7A shows a case of a smaller pressing-into amount, FIG. 7B shows a case of an appropriate pressing-into amount, and FIG. 7C shows a case of a larger pressing-into amount.
- the numeral F 1 indicates a front direction in a longitudinal direction of the burnishing tool
- the numeral R 1 indicates a rear direction in a longitudinal direction of the burnishing tool.
- FIG. 1 shows a half-sectional view of a dimple-forming burnishing tool (hereafter, referred to as a burnishing tool) according to the embodiment of the invention.
- a burnishing tool hereafter, referred to as a burnishing tool
- the upper side of the burnishing tool relative to the axis CL is shown by the sectional view, and the lower side thereof is shown by the side view.
- the front direction F 1 and the rear direction R 1 of the burnishing tool are set for clear description, as shown in FIG. 1 .
- the burnishing tool 1 includes: a mandrel 2 having a rear end side which is rotatably fitted to a processing machine (not shown in Figs.) such as a machining center or an NC milling machine; and a frame 4 which is fixed to the front end side of the mandrel from the outside and which holds balls 3 contacting the outer peripheral surface 23 on the mandrel 2 .
- a processing machine not shown in Figs.
- a frame 4 which is fixed to the front end side of the mandrel from the outside and which holds balls 3 contacting the outer peripheral surface 23 on the mandrel 2 .
- the mandrel 2 is formed in a round bar-shape as a whole.
- the mandrel 2 includes a shank portion 21 fitted to the processing machine, and a body portion 22 having the frame 4 fitted thereto from the outside.
- the mandrel 2 is composed of an integral member having the shank portion 21 and the body portion 22 formed integrally with each other, thereby preventing additional vibrations from transmitting, enhancing stiffness, and ensuring stable flexibility.
- the shank portion 21 adopts a straight shape as shown in FIG. 1 , and, in addition, various shapes such as a taper shape for adapting to a processing machine for fitting.
- the body portion 22 includes a trunk portion 24 continuous with the shank portion 21 ; and a front portion 25 which is smaller in diameter than the trunk portion 24 and which has an outer peripheral surface 23 contacting the balls 23 .
- the front portion 25 may not be necessarily smaller in diameter than the trunk portion 24 .
- the frame 4 is formed in approximately a cylindrical shape as a whole.
- the frame 4 includes a frame body 41 which is fitted to the mandrel 2 from the outside, and a frame cover 42 which is fitted to the frame body 41 from the outside.
- the frame body 41 includes a holding portion 44 which is formed with first through-holes 43 for the balls 33 to be fitted therein.
- the frame body 41 includes a fitting portion 45 which is larger in diameter than the holding portion 44 for fitting the frame 4 to the mandrel 2 .
- the frame body 41 includes an intermediate portion 46 which connects the holding portion 44 and the fitting portion 45 .
- Each of the first through-holes 43 has an inner diameter slightly larger than the diameter of each ball 3 . The respective balls 3 are fitted into the corresponding first through-holes 43 for holding.
- the fitting portion 45 of the frame body 41 has, on a rear side thereof, thread-holes 47 (for example, three pieces) which are formed at equal angular intervals on the circular periphery and which extend radially of the frame body 41 .
- the mandrel 2 has the trunk portion 24 which is formed, on the outer peripheral surface, with an annular recessed portion 26 in a V-shaped section. Stopper screws 61 are screwed into the thread-holes 47 to be pressed against the inner surface on the annular recessed portion 26 formed to the trunk portion 24 , which fixes the frame 4 to the mandrel 2 .
- the thread-holes 47 and the annular recessed portion 26 are located in the longitudinal direction in such a way that the distal ends of the stopper screws 61 come in contact with the front oblique surface of the inner surface on the annular recessed portion 26 . Therefore, the rear end surface on the intermediate portion 46 of the frame body 41 comes in contact with the front end surface on the trunk portion 24 of the mandrel 2 , which securely positioned the frame 4 to the mandrel 2 .
- the frame body 41 of the frame 4 has a stepped shape in which the holding portion 44 and the fitting portion 45 larger in diameter than the holder portion 44 are connected by the intermediate portion 46 , and is fixed to the mandrel 2 at the fitting potion 45 of a larger diameter.
- This constitution enhances the stiffness compared with a frame in a cylindrical shape having little step, and is capable of rigidly fixing the frame 4 to the mandrel 2 . This prevents the distal end side (front side) of the burnishing tool 1 from being displaced, and thereby achieves further stability.
- the frame cover 42 in a cylindrical shape is formed with second through-holes 48 which coincide in position with the first through-holes 43 , respectively.
- Each of the second through-holes 48 has an inner diameter smaller than the diameter of each ball 3 .
- the second through-holes 48 allow the balls 3 to project radially outward from the outer peripheral surface of the frame 4 , and have function to prevent the balls 3 from dropping out of the first through-holes 43 .
- the frame cover 42 is fitted to the frame body 41 from the outside with the first through-holes 43 and the second through-holes 48 coinciding in position with each other, and is fixed to the frame body 41 by clamps 5 (for example, two pieces).
- Each of the clamps 5 in an L-shape includes a fitting portion 51 having a through-hole 53 for a screw member 62 to be inserted therein, and a holding portion 52 having the frame cover 42 held between the holding portion 52 and the frame body 41 .
- the frame body 41 has the fitting portion 45 which has, at the front side, threaded holes 49 (for example, two pieces) formed at equal angular intervals on the circular periphery and extending radially of the frame body 41 .
- the screw member 62 is inserted through the through-hole 53 to be screwed into the threaded hole 49 , and thereby the frame cover 42 is held and fixed between the clamp 5 and the frame body 41 .
- the frame 4 is constituted by two separate members of the frame body 41 and the frame cover 42 . This constitution facilitates machining for forming holes for holding the balls 3 held, and enhances manufacturing operability for the burnishing tool 1 . It is noted that the frame 4 may be constituted by an integral member having the frame body 41 and the frame cover 42 formed integrally with each other.
- the balls 3 are arranged at angular intervals in the peripheral direction of the frame 4 , and are arranged at intervals in a direction parallel with the axis CL (referred to as an axial direction) of the frame (common axis with that of the burnishing tool 1 ).
- This constitution enables dimples 71 (see FIG. 4 ) to be more efficient formed on the work surface 7 (see FIG. 2 ).
- the positions of the first through-holes 43 in the frame body 41 and the positions of the second through-holes 48 in the frame cover 42 are determined, depending on the arrangement layout of the balls 3 .
- the balls 3 are axially arranged in ball rows at the respective four peripheral positions which are spaced at intervals of 90 degree in the peripheral direction of the frame 4 .
- the balls 3 in neighboring ball rows are slightly displaced axially from each other. It is noted that the placement number of the balls 3 and the arrangement layout of the balls 3 such as peripheral or axial arrangement intervals of the balls 3 may vary, depending on a size or a material of the work surface 7 (see FIG. 2 ).
- FIG. 2 is a general perspective view of the burnishing tool which shows an example of the use.
- FIG. 3 is a schematic perspective view of the front periphery of the mandrel before the mandrel is flexed.
- FIG. 4 is a schematic view of a front periphery of the mandrel with the mandrel flexed during the formation of dimples.
- FIG. 5 is a perspective view which schematically shows the front periphery of the mandrel with the mandrel flexed during the formation of dimples.
- the shape of the mandrel 2 is exaggeratingly drawn for convenient description, and the number of balls 3 is drawn differently from the actual one ( FIG. 7 is the same as ones).
- FIG. 5 the shape of the mandrel 2 is exaggeratingly drawn for convenient description, and the balls 3 are not shown in the Figure.
- the burnishing tool 1 is a tool for contacting the balls 3 on the outer peripheral surface 23 (see FIG. 1 ) with the work surface 7 on the work W with the mandrel 2 and the frame 4 rotating, thereby to form the dimples 71 (see FIG. 4 ) on the work surface 7 .
- the work surface 7 is a side surface on a groove portion S formed to the work W.
- the burnishing tool 1 is pressed into the work surface 7 by a predetermined press-into amount in a direction of P (see FIG. 2 ) from the position (see FIG. 3 ) where the ball 3 at the most distal end side (front side F 1 ) contacts just or slightly the work surface 7 (see FIG. 4 ).
- the mandrel 2 flexes oppositely to the work surface 7 as it extends toward the distal end side, with the axis CL (common axis with that of the burnishing tool 1 ) having a maximum flexion of ⁇ at the distal end of the mandrel 2 , thereby forming the dimples 71 on the work surface 7 .
- the diameter of the outer peripheral 23 on the mandrel 2 is set so as to vary along the axis CL depending on the shape of the work surface 7 . Therefore, in relation to the distance L between the contact surface 23 a of the outer peripheral surface 23 on a side closer to the work surface 7 and the work surface 7 and normal to the work surface 7 , the distance difference between the side closer to the processing machine (processing machine side or rear side) and the opposite side (front side) to the processing machine side becomes smaller than that before flexing of the mandrel 2 (see FIG. 3 ).
- the distance L between the contact surface 23 a and the work surface 7 at the front side is smaller than that at the rear side before flexing of the mandrel 2 (see FIG. 3 ).
- the front side of the outer peripheral surface 23 has approximately the same distance as that of the rear side thereof.
- the mandrel 2 before being flexed is a mandrel 2 without being flexed, if the work surface 7 is assumed not to apply reaction force.
- the diameter of the outer peripheral surface 23 on the mandrel 2 at the opposite side (front side) to the processing machine side is set to be greater than that at the processing machine side (rear side). Therefore, a parallel degree between the sectional line 27 and the sectional line 72 with the mandrel 2 flexed during formation of the dimples 71 becomes smaller than that before flexing of the mandrel 2 .
- the sectional line 27 on the outer peripheral surface 23 is defined by sectioning the outer peripheral surface 23 by the plane M and is positioned on a side of the outer peripheral surface 23 closer to the work surface 7 (work surface side).
- the plane M includes the axis CL of the mandrel 2 and is normal to the work surface 7 .
- the sectional line 72 on the work surface 7 is defined by sectioning the work surface 7 by the plane M.
- the work surface 7 is a conception that means a plane which is not only the work surface 7 itself but also includes the work surface 7 .
- the sectional line 27 on the outer peripheral surface 23 at the work surface 7 side and the sectional line 72 on the work surface 7 get closer to each other toward the front side F 1 , not being parallel with each other, while they are approximately parallel with each other with the mandrel 2 being flexed (see FIG. 4 ).
- This parallel degree defines a magnitude of deviation (error) from a straight line which is to be parallel with the standard straight line.
- the mandrel 2 has the front portion 25 having the outer peripheral surface 23 in a side-shape of a frustum of a circular cone which diverges in diameter toward the opposite side (front side) relative to the processing machine side. That is, the outer peripheral surface 23 of the mandrel 2 is formed in a taper shape having a thick distal end, which has a predetermined inclined angle (for example, 10 minutes, or 1 ⁇ 6 degree).
- the sectional line 27 at the work surface 7 side of the outer peripheral surface 23 with the mandrel 2 flexed becomes strictly a curved line, not a straight line
- the parallel degree between the sectional line 27 at the work surface 7 side of the outer peripheral surface 23 and the sectional line 72 on the work surface 7 is enabled to become sufficiently smaller.
- Formation of the outer peripheral surface 23 of the mandrel 2 in a side-shape of a frustum of a circular is made by minor modification from formation of the mandrel 2 in a side-shape of a straight circular cylinder in the manufacturing process of the mandrel 2 itself.
- the mandrel 2 , the balls 3 and the frame 4 are required to have durability, are composed of a special alloy steel, and are heat-treated for enhancing hardness and toughness. They may be treated by surface coating such as DLC, TIN or TICN for enhancing durability, depending on working condition.
- the mandrel 2 and the balls 3 may be composed of a material such as cemented carbide or a ceramic material.
- FIGS. 6A and 6B are views which show formation of dimples by the burnishing tool.
- FIG. 6A is a general view as viewed from the position opposed to the work surface.
- FIG. 6B is an enlarged view of the dimples formed on the work surface as shown by FIG. 6A .
- FIGS. 7A , 7 B and 7 C are schematic views of the burnishing tool and the work surface when the burnishing tool is pressed into the work surface with the press-into amount varied.
- FIG. 7A shows a case of a smaller press-into amount
- FIG. 7B shows a case of an appropriate press-into amount
- FIG. 7C shows a case of a larger press-into amount.
- an electric source (not shown in Figs) is started to permit the burnishing tool 1 , fitted to a processing machine (not shown in Figs), for example, an NC milling machine, to rotate at a predetermined rotational speed in a direction of R 2 (see FIG. 2 ).
- a processing machine for example, an NC milling machine
- the frame 4 is fixed to the mandrel 2 , and the mandrel 2 and the frame 4 rotate integrally with each other.
- the burnishing tool 1 is fed at a predetermined feed rate in a direction of the arrow Q, or an extension direction of the grove portion S.
- this operation permits the balls 3 , held by the frame 4 on the outer peripheral surface 23 of the mandrel 2 rotating, to intermittently contact the work surface 7 corresponding to a side surface on the groove portion S of the work W, thereby forming dimples 71 over a whole predetermined region of the work surface 7 .
- the depths of the dimples 71 become smaller than the press-into amounts of the balls 3 due to a repulsion force from the work W and the like.
- the dimples 71 are formed on the work surface 7 at intervals of a horizontal arrangement-pitch P 1 in a peripheral direction of the mandrel 2 or a direction of the arrow Q and at intervals of a vertical arrangement-pitch P 2 in an axial direction parallel with the axis CL of the mandrel 2 (see FIG. 6B ).
- the horizontal arrangement-pitch P 1 corresponds to a feed rate in a direction of the arrow Q per a rotation of the burnishing tool 1 .
- the vertical arrangement-pitch P 2 corresponds to each axial displacement between the balls 3 in each of the ball arrangements neighboring at intervals of 90 degree on the circular periphery of the frame 4 .
- the burnishing tool 1 is separated apart from the work W to be stopped from rotating.
- the previous experiment determined said press-into amount by which the burnishing tool 1 is further pressed into the work surface 7 from the position for the ball 3 at the most distal end side (front side) to contact just and slightly the work surface 7 .
- the balls 3 located at the rear side on the outer peripheral surface 23 are pressed against the work surface 7 more strongly than those located at the front side. Therefore, the dimples 3 formed at the rear side become deeper than the dimples 71 formed at the front side. In the worst case, there is some possibility of not forming the dimples 71 at the front side.
- FIG. 7B if a press-into amount is appropriate, the sectional line 27 on the work surface 7 side of the outer peripheral surface 23 and the sectional line 72 on the work surface 7 become approximately parallel with each other with the mandrel 2 flexed.
- the balls 3 located at the front side of the outer peripheral surface 23 and the balls 3 located at the rear side are pressed against the work surface 7 at a further uniform strength. This operation permits the depths of the dimples 71 formed at the front side and the depths of the dimples 71 at the rear side to become approximately uniform.
- the experiment determined the press-into amount for forming the dimples 71 of approximately a uniform depth on the work surface 7 .
- a size, a depth, an arrangement-pitch and an arrangement aspect of the dimples 71 may be modified by varying a machining condition (a rotation rate of the burnishing tool 1 and a feed rate); a diameter, an arrangement layout, the number, the arrangement layout and the mass of the balls 3 ; an inclined angle (taper angle) of the outer peripheral surface 23 on the mandrel 2 ; a force of pressing the balls 3 against the work surface 7 and the like. Following this, a material property (hardness) of the work surface 7 on the work W may be considered.
- the burnishing tool 1 is structured so as to be applied to formation of the dimples 71 on the work surface 7 corresponding to the side surface of the groove portion S that has a depth of about 20 mm to about 50 mm and a width of about 20 mm. If the burnishing tool 1 is applied to another groove portion S of a different size and the like, the measure may be taken by fabricating a burnishing tool 1 of a different size in diameter and length at the design stage or by removing the frame 4 and the balls 3 from the mandrel 2 to be exchanged to ones of a different specification.
- the burnishing tool 1 of the embodiment includes: the mandrel 2 having a rear end side fitted to the processing machine for rotating; and the frame 4 fitted and fixed to the front end side of the mandrel 2 from the outside to hold the balls 3 that contact the outer peripheral surface 23 on the mandrel 2 .
- the mandrel 2 and the frame 4 rotating, the balls 3 on the outer peripheral surface 23 contact with the work surface 7 , thereby forming the dimples 71 on the work surface 7 .
- the diameter of the outer peripheral on the mandrel 2 is set in such a way that in relation to the distance L between the contact surface 23 a with the balls 3 on the work surface 7 side of the outer peripheral surface 23 and the work surface 7 and normal to the work surface 7 , the distance difference between the front side and the rear side with the mandrel 2 flexed during formation of the dimples 71 becomes smaller than that before flexing of the mandrel 2 .
- the mandrel 2 is flexed during formation of the dimples 71 due to the burnishing tool 1 of a smaller diameter, all of the balls 3 arranged on the outer peripheral surface 23 are pressed against the work surface 7 at a further uniform strength with the mandrel 2 being flexed.
- This operation forms the dimples 71 of approximately a uniform depth, for example, on the whole predetermined region on the work surface 7 of a narrow portion such as a side surface of the groove portion S. That is, the dimples 71 are enabled to be efficiently and securely formed on the work surface 7 of the narrow portion such as the side surface of the groove portion S.
- the work surface 7 on the work W is formed with very fine and uniform dimples 71 , which are capable of keeping lubricant. This function prevents oil from running out on the work surface 7 , and reduces frictional resistance, thereby enhancing the sliding property.
- the burnishing tool 1 is fitted to a generic processing machine (a machine tool) such as an NC milling machine, and is capable of forming dimples in a shape which is required at ease and an inexpensive price.
- a generic processing machine a machine tool
- NC milling machine a machine tool
- the burnishing tool 1 is fitted to a generic processing machine (a machine tool) such as an NC milling machine, and is capable of forming dimples in a shape which is required at ease and an inexpensive price.
- the embodiment explains that the burnishing tool 1 is fitted to a processing machine of a vertical type with the axis CL extending in a vertical direction.
- the invention is not limited to this aspect, and, for example, the burnishing tool 1 may be fitted to a machining tool of a horizontal type with the axis CL extending in a horizontal direction for use.
- the present invention is not limited to this aspect.
- the present invention is applicable to the case where work surface 7 is curved in a section which is defined by sectioning the work surface 7 by a horizontal plane (planar view).
- the invention is applicable to the case where the work surface 7 is a side surface of a scroll groove in a compressor component or the case where the work surface 7 is an inner peripheral surface 7 of a hole formed to the work W and the like.
- the invention is applicable to the case where the work surface 7 is a plane inclined to the vertical axis.
- the burnishing tool 1 is fitted to, for example, the five axis processing machine, and is used with the axis CL being parallel with the work surface 7 . That is, considering a shape and an angle of the work surface 7 , a movement control and a rotation (rotary motion) control are combined and performed to form the dimples 71 on the work surface 7 of the work W.
- the movement control is a control of moving in three axis directions, the X axis, the Y axis and the Z axis orthogonal to each other, of a machining head (not show in Figs) for fitting the burnishing tool 1 .
- the rotation control is a control of rotating about two axis, or the A/B axis and the C axis, of a work-fixing portion (not shown in Figs) for fixing the work W.
- the present invention is applicable to the case where the work surface 7 is curved in a section (as viewed from the front) which is defined by sectioning the work surface 7 by, for example, the vertical plane.
- the diameter of the outer peripheral surface 23 a varies along the axis CL, depending on a shape of the curved work surface 7 , and is set in such a way that the distance L between the contact surface 23 a and the work surface 7 at the front side of the outer peripheral surface on the mandrel 2 becomes approximately the same as that at the rear side thereof.
- the frame 4 may be formed with elongated circular through-holes, to which a plurality of balls 3 are fitted.
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- Engineering & Computer Science (AREA)
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- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
- Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
Abstract
A burnishing tool includes a mandrel; and a frame fitted to the mandrel and holding balls contacting an outer peripheral surface on the mandrel. The outer peripheral surface has a contact surface with the balls. The contact surface is at a side of the outer peripheral surface which is closer to the work surface. The contact surface and the work surface have a distance therebetween in a direction normal to the work surface. A distance at a side of the mandrel closer to the processing machine and a distance at the opposite side of the mandrel have a distance difference therebetween. A diameter of the outer peripheral surface on the mandrel is set in such a way that the distance difference with the mandrel flexed during formation of the dimples becomes smaller than that before flexing of the mandrel.
Description
- This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2012-035752 filed on Feb. 22, 2012; the entire contents of which are incorporated herein by reference.
- 1. Field of the Invention
- The invention relates to a dimple-forming burnishing tool and a dimple-forming burnishing method for forming a dimple on a work surface by contacting a ball with the work surface.
- 2. Description of Related Art
- There is a technique of forming fine dimples for keeping a lubricant on a sliding surface of a sliding member such as a bearing to reduce friction resistance of the sliding surface. The surface treatment for forming the dimples on a work surface such as the sliding surface has been known as a dimple-forming by a WPC treatment (fine-particle shot-peening), a dimple-forming by a laser-machining and the like.
- The dimple-forming by the WPC treatment is a surface treatment of shooting fine particles, smaller than those for an ordinary peening, at a high speed to be struck on the work surface for forming dimples. The dimple-forming by the laser-machining is a surface treatment of radiating laser beam on the work surface using an exclusive processing machine for forming dimples.
- There is proposed another surface treatment for forming dimples on a work surface using a burnishing tool (see, for example, Patent Document 1). The burnishing tool includes a cylindrical frame fitted to a mandrel from the outside. The cylindrical frame holds rotatably rolling elements to come radially out of or into the outer peripheral surface of the frame. With the mandrel fitted to a processing machine rotated, the projections, formed on the outer peripheral surface of the mandrel, engage rolling elements such as balls. The rolling elements vibratingly rotate on the inner peripheral surface of a work as a work surface.
- [Patent Document 1] Japanese Patent Publication NO. 4575899
- However, when the surface treatment of forming dimples is applied to the work surface of a narrow portion such as the side surface of the groove portion of a compressor component, the problem has been proposed as follows.
- That is, the WPC treatment requires shooting particles at every surface treatment, which raises machining cost, and is not efficient. The laser-machining is difficult to be applied to the work surface of the narrow portion such as a side surface of the groove portion.
- The burnishing tool as described in
Patent Document 1 is a tool used for the surface treatment to the inner peripheral surface of a hole formed to a work, and is not applied to the surface treatment to a work surface such as a side surface of the groove portion. If the tool is used on the work surface of the narrow portion such as the side surface of the groove portion, a tool diameter becomes smaller, and the tool is flexed during formation of dimples. This causes difficulty in to forming dimples by secure contacting all of the rolling elements on the work surface. - The invention is directed to a dimple-forming burnishing tool and a dimple-forming burnishing method which efficiently and securely form dimples to a work surface of a narrow portion such as a side surface of a groove portion.
- A first aspect of the invention provides a dimple-forming burnishing tool. The dimple-forming burnishing tool includes a mandrel having an end side fitted and fixed to a processing machine for rotating; and a frame fitted to another side of the mandrel from the outside, and holding balls contacting an outer peripheral surface of the mandrel. The balls on the outer peripheral surface contact a work surface with the mandrel and the frame rotated for forming dimples on the work surface. The outer peripheral surface has a contact surface with the balls. The contact surface is at a side of the outer peripheral surface which is closer to the work surface. The contact surface and the work surface have a distance therebetween in a direction normal to the work surface. A distance at a side of the mandrel closer to the processing machine and a distance at the opposite side of the mandrel to said side have a distance difference therebetween. A diameter of the outer peripheral surface on the mandrel is set in such a way that the distance difference with the mandrel flexed during formation of the dimples becomes smaller than that before flexing of the mandrel.
- According to the invention, if the mandrel is flexed during formation of the dimples, the burnishing tool of a smaller diameter enables all of the balls arranged on the outer peripheral surface to be pressed against the work surface with the mandrel flexed. This operation forms the dimples of approximately a uniform depth at a predetermined whole region on the work surface of a narrow portion which is a side surface of, for example, a groove portion.
- That is, the dimples are efficiently and securely formed to the work surface of the narrow portion such as a side surface of the groove portion.
- Therefore, the work surface is formed with very fine and uniform dimples, and keeps a lubricant in the dimples. This prevents a lubricant from running out, and reduces frictional resistance, thereby enhancing the sliding property.
- The dimple-forming burnishing tool is fitted to a generic processing machine (machine tool) such as a machining center, or an NC milling machine for use, and is capable of forming dimples in a shape which is required with ease and at an inexpensive cost.
- The mandrel has a first sectional line which is positioned on the outer peripheral surface and at said side of the mandrel closer to the work surface. The first sectional line is defined by sectioning the mandrel by a plane which is normal to the work surface and includes an axis of the mandrel. The work surface has a second sectional line on the work surface. The second sectional line is defined by sectioning the work surface by the plane. The first sectional line and the second sectional line have a parallel degree therebetween. A diameter of the outer peripheral on the mandrel at the opposite side to a side closer to the processing machine is set to be larger than that at said side close to the processing machine, so that the parallel degree with the mandrel flexed during formation of the dimples becomes smaller than that before flexing of the mandrel.
- According to the invention, it is applicable to the case where the work surface is a plane. With the mandrel is flexed during formation of the dimples, the sectional line at the side of the outer peripheral surface closer to the work surface is approximately parallel with the sectional line on the work surface. This permits all of the balls arranged on the outer peripheral surface to be pressed against the work surface at a further uniform strength.
- The outer peripheral surface of the mandrel has a side shape in a frustum of a circular cone which diverges toward the opposite side to said side closer to the processing machine.
- According to the invention, with the mandrel being flexed, the sectional line at a side of the outer peripheral surface closer to the work surface is exactly a curved line, not a straight line. On the other hand, a parallel degree between the sectional line at a side of the outer peripheral surface closer to the work surface and the sectional line on the work surface become sufficiently smaller. Herein, formation of the outer peripheral surface of the mandrel in a side-shape of a frustum of a circular is made by minor change from formation of the mandrel in a side-shape of a straight circular cylinder in the manufacturing process of the mandrel itself.
- The balls are spaced apart from each other in a peripheral direction of the frame and in a direction parallel with the axis of the frame.
- According to the invention, it is enabled to further efficiently form the dimples on the work surface.
- The frame includes: a frame body fitted to the mandrel from the outside and defining first through-holes for the balls to be fitted thereto, respectively; and a frame cover fitted to the frame body from the outside, having the balls projecting radially outward from the outer peripheral surface of the frame, and defining second through-holes which coincide in position with the first through-holes for preventing the balls from dropping out of the first through-holes, respectively.
- According to the invention, it facilitates machining such as formation of holes for holding the balls, thereby enhancing manufacturing operability for the dimple-forming burnishing tool.
- A second aspect of the invention provides a dimple-forming burnishing method which includes contacting the balls on the work surface to form dimples on the work surface using the dimple-forming burnishing tool according to the first aspect of the invention.
- According to the invention, it is capable of serving as the same operation and benefits as those of the first aspect of the invention.
- According to the invention, this enables the dimples to be efficiently and securely formed on the work surface of the narrow portion such as a side surface of the groove portion.
-
FIG. 1 is a half sectional view which shows a whole structure of a dimple-forming burnishing tool according to an embodiment of the invention. -
FIG. 2 is a general perspective view of the burnishing tool as show inFIG. 1 , which shows an example of working condition. -
FIG. 3 is a schematic view of the front periphery of a mandrel before the mandrel is flexed. -
FIG. 4 is a schematic view of the front periphery of the mandrel with the mandrel flexed during formation of dimples. -
FIG. 5 is a perspective view of the mandrel which schematically shows the front periphery of the mandrel with the mandrel flexed during formation of dimples. -
FIGS. 6A and 6B are views which show the state of dimple-forming by a burnishing tool,FIG. 6A is a general view as viewed from the position opposed to the work surface, andFIG. 6B is an enlarged view of the dimples formed on the work surface as shown inFIG. 6A . -
FIGS. 7A , 7B and 7C are schematic views of a mandrel which is pressed into the work surface with the pressing-into amount varied,FIG. 7A shows a case of a smaller pressing-into amount,FIG. 7B shows a case of an appropriate pressing-into amount, andFIG. 7C shows a case of a larger pressing-into amount. - In the Figures, the numeral F1 indicates a front direction in a longitudinal direction of the burnishing tool, and the numeral R1 indicates a rear direction in a longitudinal direction of the burnishing tool.
- Next, an embodiment according to the invention will be described with reference to the drawings.
FIG. 1 shows a half-sectional view of a dimple-forming burnishing tool (hereafter, referred to as a burnishing tool) according to the embodiment of the invention. InFIG. 1 , the upper side of the burnishing tool relative to the axis CL is shown by the sectional view, and the lower side thereof is shown by the side view. It is noted that the front direction F1 and the rear direction R1 of the burnishing tool are set for clear description, as shown inFIG. 1 . - As shown in
FIG. 1 , theburnishing tool 1 includes: amandrel 2 having a rear end side which is rotatably fitted to a processing machine (not shown in Figs.) such as a machining center or an NC milling machine; and aframe 4 which is fixed to the front end side of the mandrel from the outside and which holdsballs 3 contacting the outerperipheral surface 23 on themandrel 2. - The
mandrel 2 is formed in a round bar-shape as a whole. Themandrel 2 includes ashank portion 21 fitted to the processing machine, and abody portion 22 having theframe 4 fitted thereto from the outside. Themandrel 2 is composed of an integral member having theshank portion 21 and thebody portion 22 formed integrally with each other, thereby preventing additional vibrations from transmitting, enhancing stiffness, and ensuring stable flexibility. - The
shank portion 21 adopts a straight shape as shown inFIG. 1 , and, in addition, various shapes such as a taper shape for adapting to a processing machine for fitting. Thebody portion 22 includes atrunk portion 24 continuous with theshank portion 21; and afront portion 25 which is smaller in diameter than thetrunk portion 24 and which has an outerperipheral surface 23 contacting theballs 23. Thefront portion 25 may not be necessarily smaller in diameter than thetrunk portion 24. - The
frame 4 is formed in approximately a cylindrical shape as a whole. Theframe 4 includes aframe body 41 which is fitted to themandrel 2 from the outside, and aframe cover 42 which is fitted to theframe body 41 from the outside. - The
frame body 41 includes a holdingportion 44 which is formed with first through-holes 43 for the balls 33 to be fitted therein. Theframe body 41 includes afitting portion 45 which is larger in diameter than the holdingportion 44 for fitting theframe 4 to themandrel 2. Theframe body 41 includes anintermediate portion 46 which connects the holdingportion 44 and thefitting portion 45. Each of the first through-holes 43 has an inner diameter slightly larger than the diameter of eachball 3. Therespective balls 3 are fitted into the corresponding first through-holes 43 for holding. - The
fitting portion 45 of theframe body 41 has, on a rear side thereof, thread-holes 47 (for example, three pieces) which are formed at equal angular intervals on the circular periphery and which extend radially of theframe body 41. Themandrel 2 has thetrunk portion 24 which is formed, on the outer peripheral surface, with an annular recessedportion 26 in a V-shaped section. Stopper screws 61 are screwed into the thread-holes 47 to be pressed against the inner surface on the annular recessedportion 26 formed to thetrunk portion 24, which fixes theframe 4 to themandrel 2. Herein, the thread-holes 47 and the annular recessedportion 26 are located in the longitudinal direction in such a way that the distal ends of the stopper screws 61 come in contact with the front oblique surface of the inner surface on the annular recessedportion 26. Therefore, the rear end surface on theintermediate portion 46 of theframe body 41 comes in contact with the front end surface on thetrunk portion 24 of themandrel 2, which securely positioned theframe 4 to themandrel 2. - The
frame body 41 of theframe 4 has a stepped shape in which the holdingportion 44 and thefitting portion 45 larger in diameter than theholder portion 44 are connected by theintermediate portion 46, and is fixed to themandrel 2 at thefitting potion 45 of a larger diameter. This constitution enhances the stiffness compared with a frame in a cylindrical shape having little step, and is capable of rigidly fixing theframe 4 to themandrel 2. This prevents the distal end side (front side) of theburnishing tool 1 from being displaced, and thereby achieves further stability. - The frame cover 42 in a cylindrical shape is formed with second through-
holes 48 which coincide in position with the first through-holes 43, respectively. Each of the second through-holes 48 has an inner diameter smaller than the diameter of eachball 3. The second through-holes 48 allow theballs 3 to project radially outward from the outer peripheral surface of theframe 4, and have function to prevent theballs 3 from dropping out of the first through-holes 43. - The
frame cover 42 is fitted to theframe body 41 from the outside with the first through-holes 43 and the second through-holes 48 coinciding in position with each other, and is fixed to theframe body 41 by clamps 5 (for example, two pieces). Each of theclamps 5 in an L-shape includes afitting portion 51 having a through-hole 53 for ascrew member 62 to be inserted therein, and a holdingportion 52 having theframe cover 42 held between the holdingportion 52 and theframe body 41. Theframe body 41 has thefitting portion 45 which has, at the front side, threaded holes 49 (for example, two pieces) formed at equal angular intervals on the circular periphery and extending radially of theframe body 41. Thescrew member 62 is inserted through the through-hole 53 to be screwed into the threaded hole 49, and thereby theframe cover 42 is held and fixed between theclamp 5 and theframe body 41. - The
frame 4 is constituted by two separate members of theframe body 41 and theframe cover 42. This constitution facilitates machining for forming holes for holding theballs 3 held, and enhances manufacturing operability for theburnishing tool 1. It is noted that theframe 4 may be constituted by an integral member having theframe body 41 and theframe cover 42 formed integrally with each other. - The
balls 3 are arranged at angular intervals in the peripheral direction of theframe 4, and are arranged at intervals in a direction parallel with the axis CL (referred to as an axial direction) of the frame (common axis with that of the burnishing tool 1). This constitution enables dimples 71 (seeFIG. 4 ) to be more efficient formed on the work surface 7 (seeFIG. 2 ). Herein, the positions of the first through-holes 43 in theframe body 41 and the positions of the second through-holes 48 in theframe cover 42 are determined, depending on the arrangement layout of theballs 3. - In
FIG. 1 , theballs 3 are axially arranged in ball rows at the respective four peripheral positions which are spaced at intervals of 90 degree in the peripheral direction of theframe 4. Theballs 3 in neighboring ball rows are slightly displaced axially from each other. It is noted that the placement number of theballs 3 and the arrangement layout of theballs 3 such as peripheral or axial arrangement intervals of theballs 3 may vary, depending on a size or a material of the work surface 7 (seeFIG. 2 ). -
FIG. 2 is a general perspective view of the burnishing tool which shows an example of the use.FIG. 3 is a schematic perspective view of the front periphery of the mandrel before the mandrel is flexed.FIG. 4 is a schematic view of a front periphery of the mandrel with the mandrel flexed during the formation of dimples.FIG. 5 is a perspective view which schematically shows the front periphery of the mandrel with the mandrel flexed during the formation of dimples. InFIGS. 3 and 4 , the shape of themandrel 2 is exaggeratingly drawn for convenient description, and the number ofballs 3 is drawn differently from the actual one (FIG. 7 is the same as ones). InFIG. 5 , the shape of themandrel 2 is exaggeratingly drawn for convenient description, and theballs 3 are not shown in the Figure. - As shown in
FIG. 2 , theburnishing tool 1 is a tool for contacting theballs 3 on the outer peripheral surface 23 (seeFIG. 1 ) with thework surface 7 on the work W with themandrel 2 and theframe 4 rotating, thereby to form the dimples 71 (seeFIG. 4 ) on thework surface 7. Thework surface 7 is a side surface on a groove portion S formed to the work W. - As shown in
FIGS. 3 to 5 , theburnishing tool 1 is pressed into thework surface 7 by a predetermined press-into amount in a direction of P (seeFIG. 2 ) from the position (seeFIG. 3 ) where theball 3 at the most distal end side (front side F1) contacts just or slightly the work surface 7 (seeFIG. 4 ). At this time, themandrel 2 flexes oppositely to thework surface 7 as it extends toward the distal end side, with the axis CL (common axis with that of the burnishing tool 1) having a maximum flexion of δ at the distal end of themandrel 2, thereby forming thedimples 71 on thework surface 7. - In the embodiment, with the
mandrel 2 flexed during formation of the dimples 71 (seeFIGS. 4 and 5 ), the diameter of the outer peripheral 23 on themandrel 2 is set so as to vary along the axis CL depending on the shape of thework surface 7. Therefore, in relation to the distance L between thecontact surface 23 a of the outerperipheral surface 23 on a side closer to thework surface 7 and thework surface 7 and normal to thework surface 7, the distance difference between the side closer to the processing machine (processing machine side or rear side) and the opposite side (front side) to the processing machine side becomes smaller than that before flexing of the mandrel 2 (seeFIG. 3 ). To be specific, the distance L between thecontact surface 23 a and thework surface 7 at the front side is smaller than that at the rear side before flexing of the mandrel 2 (seeFIG. 3 ). With themandrel 2 flexed (seeFIGS. 4 and 5 ), the front side of the outerperipheral surface 23 has approximately the same distance as that of the rear side thereof. Herein, themandrel 2 before being flexed is amandrel 2 without being flexed, if thework surface 7 is assumed not to apply reaction force. - The diameter of the outer
peripheral surface 23 on themandrel 2 at the opposite side (front side) to the processing machine side is set to be greater than that at the processing machine side (rear side). Therefore, a parallel degree between thesectional line 27 and thesectional line 72 with themandrel 2 flexed during formation of thedimples 71 becomes smaller than that before flexing of themandrel 2. Thesectional line 27 on the outerperipheral surface 23 is defined by sectioning the outerperipheral surface 23 by the plane M and is positioned on a side of the outerperipheral surface 23 closer to the work surface 7 (work surface side). The plane M includes the axis CL of themandrel 2 and is normal to thework surface 7. Thesectional line 72 on thework surface 7 is defined by sectioning thework surface 7 by the plane M. Thework surface 7 is a conception that means a plane which is not only thework surface 7 itself but also includes thework surface 7. To be specific, thesectional line 27 on the outerperipheral surface 23 at thework surface 7 side and thesectional line 72 on thework surface 7 get closer to each other toward the front side F1, not being parallel with each other, while they are approximately parallel with each other with themandrel 2 being flexed (seeFIG. 4 ). This parallel degree defines a magnitude of deviation (error) from a straight line which is to be parallel with the standard straight line. - This constitution is applied to the case in which the
work surface 7 of the embodiment is a plane. With themandrel 2 flexed during formation of thedimples 71, thesectional line 27 on the outerperipheral surface 23 at thework surface 7 side and thesectional line 72 on thework surface 7 are approximately parallel with each other, which enables all of theballs 3 arranged on the outerperipheral surface 23 to be pressed against thework surface 7 at a more uniform strength. - In the embodiment, the
mandrel 2 has thefront portion 25 having the outerperipheral surface 23 in a side-shape of a frustum of a circular cone which diverges in diameter toward the opposite side (front side) relative to the processing machine side. That is, the outerperipheral surface 23 of themandrel 2 is formed in a taper shape having a thick distal end, which has a predetermined inclined angle (for example, 10 minutes, or ⅙ degree). - According to this constitution, the
sectional line 27 at thework surface 7 side of the outerperipheral surface 23 with themandrel 2 flexed becomes strictly a curved line, not a straight line, the parallel degree between thesectional line 27 at thework surface 7 side of the outerperipheral surface 23 and thesectional line 72 on thework surface 7 is enabled to become sufficiently smaller. Formation of the outerperipheral surface 23 of themandrel 2 in a side-shape of a frustum of a circular is made by minor modification from formation of themandrel 2 in a side-shape of a straight circular cylinder in the manufacturing process of themandrel 2 itself. - The
mandrel 2, theballs 3 and theframe 4 are required to have durability, are composed of a special alloy steel, and are heat-treated for enhancing hardness and toughness. They may be treated by surface coating such as DLC, TIN or TICN for enhancing durability, depending on working condition. Themandrel 2 and theballs 3 may be composed of a material such as cemented carbide or a ceramic material. - Next, a dimple-forming burnishing method using the above-structured
burnishing tool 1 is described with reference toFIGS. 1 to 5 andFIGS. 6 and 7 . -
FIGS. 6A and 6B are views which show formation of dimples by the burnishing tool.FIG. 6A is a general view as viewed from the position opposed to the work surface.FIG. 6B is an enlarged view of the dimples formed on the work surface as shown byFIG. 6A .FIGS. 7A , 7B and 7C are schematic views of the burnishing tool and the work surface when the burnishing tool is pressed into the work surface with the press-into amount varied.FIG. 7A shows a case of a smaller press-into amount;FIG. 7B shows a case of an appropriate press-into amount; andFIG. 7C shows a case of a larger press-into amount. - Firstly, an electric source (not shown in Figs) is started to permit the
burnishing tool 1, fitted to a processing machine (not shown in Figs), for example, an NC milling machine, to rotate at a predetermined rotational speed in a direction of R2 (seeFIG. 2 ). At this time, theframe 4 is fixed to themandrel 2, and themandrel 2 and theframe 4 rotate integrally with each other. - Subsequently, as shown in
FIGS. 2 and 6 , with the press-into amount for pressing theballs 3 into thework surface 7 set to a predetermined value, theburnishing tool 1 is fed at a predetermined feed rate in a direction of the arrow Q, or an extension direction of the grove portion S. - As shown in
FIG. 6 , this operation permits theballs 3, held by theframe 4 on the outerperipheral surface 23 of themandrel 2 rotating, to intermittently contact thework surface 7 corresponding to a side surface on the groove portion S of the work W, thereby formingdimples 71 over a whole predetermined region of thework surface 7. The depths of thedimples 71 become smaller than the press-into amounts of theballs 3 due to a repulsion force from the work W and the like. - The
dimples 71 are formed on thework surface 7 at intervals of a horizontal arrangement-pitch P1 in a peripheral direction of themandrel 2 or a direction of the arrow Q and at intervals of a vertical arrangement-pitch P2 in an axial direction parallel with the axis CL of the mandrel 2 (seeFIG. 6B ). The horizontal arrangement-pitch P1 corresponds to a feed rate in a direction of the arrow Q per a rotation of theburnishing tool 1. The vertical arrangement-pitch P2 corresponds to each axial displacement between theballs 3 in each of the ball arrangements neighboring at intervals of 90 degree on the circular periphery of theframe 4. - When forming the
dimples 71 on thework surface 7 is finished, theburnishing tool 1 is separated apart from the work W to be stopped from rotating. - Herein, the previous experiment determined said press-into amount by which the
burnishing tool 1 is further pressed into thework surface 7 from the position for theball 3 at the most distal end side (front side) to contact just and slightly thework surface 7. - As shown in
FIG. 7A , if the press-into amount is too small, a flexion of themandrel 2 becomes smaller. Theballs 3, located at the front side on the outerperipheral surface 23 diverging toward the distal end side (front side), are pressed against thework surface 7 more strongly than theballs 3 located at the rear side. Therefore, thedimples 3 formed at the front side become deeper than thedimples 71 formed at the rear side. In the worst case, there is some possibility of not forming thedimples 71 at the rear side. As shown inFIG. 7C , if the press-into amount is too large, flexion of themandrel 2 becomes larger. Theballs 3 located at the rear side on the outerperipheral surface 23 are pressed against thework surface 7 more strongly than those located at the front side. Therefore, thedimples 3 formed at the rear side become deeper than thedimples 71 formed at the front side. In the worst case, there is some possibility of not forming thedimples 71 at the front side. On the other hand, as shown inFIG. 7B , if a press-into amount is appropriate, thesectional line 27 on thework surface 7 side of the outerperipheral surface 23 and thesectional line 72 on thework surface 7 become approximately parallel with each other with themandrel 2 flexed. Theballs 3 located at the front side of the outerperipheral surface 23 and theballs 3 located at the rear side are pressed against thework surface 7 at a further uniform strength. This operation permits the depths of thedimples 71 formed at the front side and the depths of thedimples 71 at the rear side to become approximately uniform. - Therefore, as shown in
FIG. 7B , the experiment determined the press-into amount for forming thedimples 71 of approximately a uniform depth on thework surface 7. - A size, a depth, an arrangement-pitch and an arrangement aspect of the
dimples 71 may be modified by varying a machining condition (a rotation rate of theburnishing tool 1 and a feed rate); a diameter, an arrangement layout, the number, the arrangement layout and the mass of theballs 3; an inclined angle (taper angle) of the outerperipheral surface 23 on themandrel 2; a force of pressing theballs 3 against thework surface 7 and the like. Following this, a material property (hardness) of thework surface 7 on the work W may be considered. - The
burnishing tool 1 is structured so as to be applied to formation of thedimples 71 on thework surface 7 corresponding to the side surface of the groove portion S that has a depth of about 20 mm to about 50 mm and a width of about 20 mm. If theburnishing tool 1 is applied to another groove portion S of a different size and the like, the measure may be taken by fabricating aburnishing tool 1 of a different size in diameter and length at the design stage or by removing theframe 4 and theballs 3 from themandrel 2 to be exchanged to ones of a different specification. - As describe above, the
burnishing tool 1 of the embodiment includes: themandrel 2 having a rear end side fitted to the processing machine for rotating; and theframe 4 fitted and fixed to the front end side of themandrel 2 from the outside to hold theballs 3 that contact the outerperipheral surface 23 on themandrel 2. With themandrel 2 and theframe 4 rotating, theballs 3 on the outerperipheral surface 23 contact with thework surface 7, thereby forming thedimples 71 on thework surface 7. Herein, the diameter of the outer peripheral on themandrel 2 is set in such a way that in relation to the distance L between thecontact surface 23 a with theballs 3 on thework surface 7 side of the outerperipheral surface 23 and thework surface 7 and normal to thework surface 7, the distance difference between the front side and the rear side with themandrel 2 flexed during formation of thedimples 71 becomes smaller than that before flexing of themandrel 2. - According to this embodiment, if the
mandrel 2 is flexed during formation of thedimples 71 due to theburnishing tool 1 of a smaller diameter, all of theballs 3 arranged on the outerperipheral surface 23 are pressed against thework surface 7 at a further uniform strength with themandrel 2 being flexed. This operation forms thedimples 71 of approximately a uniform depth, for example, on the whole predetermined region on thework surface 7 of a narrow portion such as a side surface of the groove portion S. That is, thedimples 71 are enabled to be efficiently and securely formed on thework surface 7 of the narrow portion such as the side surface of the groove portion S. - Therefore, the
work surface 7 on the work W is formed with very fine anduniform dimples 71, which are capable of keeping lubricant. This function prevents oil from running out on thework surface 7, and reduces frictional resistance, thereby enhancing the sliding property. - The
burnishing tool 1 is fitted to a generic processing machine (a machine tool) such as an NC milling machine, and is capable of forming dimples in a shape which is required at ease and an inexpensive price. - As described above, though the embodiment of the invention is explained, the invention is not limited to the constitution as described in the embodiment. Although the invention has been described above by reference to the embodiment, the invention is not limited to the embodiments described above. Appropriate modifications and variations of the constitution may be made within the purpose of the invention, including appropriate combination and selection of the constitutions as described in the embodiment.
- For example, the embodiment explains that the
burnishing tool 1 is fitted to a processing machine of a vertical type with the axis CL extending in a vertical direction. However, the invention is not limited to this aspect, and, for example, theburnishing tool 1 may be fitted to a machining tool of a horizontal type with the axis CL extending in a horizontal direction for use. - Although the above-described embodiment explains that the
work surface 7 is a plane parallel with a vertical axis, the present invention is not limited to this aspect. For example, the present invention is applicable to the case wherework surface 7 is curved in a section which is defined by sectioning thework surface 7 by a horizontal plane (planar view). To be specific, the invention is applicable to the case where thework surface 7 is a side surface of a scroll groove in a compressor component or the case where thework surface 7 is an innerperipheral surface 7 of a hole formed to the work W and the like. The invention is applicable to the case where thework surface 7 is a plane inclined to the vertical axis. - In this case, the
burnishing tool 1 is fitted to, for example, the five axis processing machine, and is used with the axis CL being parallel with thework surface 7. That is, considering a shape and an angle of thework surface 7, a movement control and a rotation (rotary motion) control are combined and performed to form thedimples 71 on thework surface 7 of the work W. The movement control is a control of moving in three axis directions, the X axis, the Y axis and the Z axis orthogonal to each other, of a machining head (not show in Figs) for fitting theburnishing tool 1. The rotation control is a control of rotating about two axis, or the A/B axis and the C axis, of a work-fixing portion (not shown in Figs) for fixing the work W. - In addition, the present invention is applicable to the case where the
work surface 7 is curved in a section (as viewed from the front) which is defined by sectioning thework surface 7 by, for example, the vertical plane. In this case, with themandrel 2 flexed during the formation of thedimples 71, the diameter of the outerperipheral surface 23 a varies along the axis CL, depending on a shape of thecurved work surface 7, and is set in such a way that the distance L between thecontact surface 23 a and thework surface 7 at the front side of the outer peripheral surface on themandrel 2 becomes approximately the same as that at the rear side thereof. - In the above-described embodiment, although a
ball 3 is fitted to a circular through-hole formed to theframe 4, the present invention is not limited to this. Theframe 4 may be formed with elongated circular through-holes, to which a plurality ofballs 3 are fitted. -
- 1 dimple-forming burnishing tool
- 2 mandrel
- 23 outer peripheral surface
- 23 a contact surface
- 27 cutting-plane line
- 3 ball
- 4 frame
- 41 frame body
- 42 frame cover
- 43 first through-hole
- 48 second through-hole
- 7 work surface
- 71 dimple
- 72 cutting-plane line
- CL axis
- L distance
- M plane
Claims (6)
1. A dimple-forming burnishing tool comprising:
a mandrel having an end side fitted to a processing machine for rotating; and
a frame fitted and fixed to another side of the mandrel from the outside, and holding balls contacting an outer peripheral surface of the mandrel,
wherein the balls on the outer peripheral surface contact a work surface for forming dimples on the work surface with the mandrel and the frame rotated,
wherein the outer peripheral surface has a contact surface with the balls and,
wherein the contact surface is at a side of the outer peripheral surface which is closer to the work surface,
wherein the contact surface and the work surface have a distance therebetween in a direction normal to the work surface,
wherein a distance at a side of the mandrel closer to the processing machine and a distance at the opposite side of the mandrel have a distance difference therebetween,
wherein a diameter of the outer peripheral surface on the mandrel is set in such a way that the distance difference with the mandrel flexed during formation of the dimples becomes smaller than that before flexing of the mandrel.
2. The dimple-forming burnishing tool according to claim 1 ,
wherein the mandrel has a first sectional line which is positioned on the outer peripheral surface and at said side closer to the work surface,
wherein the first sectional line is defined by sectioning the mandrel by a plane which is normal to the work surface and includes an axis of the mandrel,
wherein the work surface has a second sectional line on the work surface,
wherein the second sectional line is defined by sectioning the work surface by the plane,
wherein the first sectional line and the second sectional line have a parallel degree therebetween,
wherein a diameter of the outer peripheral surface on the mandrel at the opposite side to said side closer to the processing machine is set to be larger than that at the side closer to the processing machine, so that the parallel degree with the mandrel flexed during formation of the dimples becomes smaller than that before flexing of the mandrel.
3. The dimple-forming burnishing tool according to claim 2 ,
wherein the outer peripheral surface of the mandrel has a side shape in a frustum of a circular cone which diverges toward the opposite side to said side closer to the processing machine.
4. The dimple-forming burnishing tool according to claim 1 , wherein the balls are spaced apart from each other in a peripheral direction of the frame and in a direction parallel with the axis of the frame.
5. The dimple-forming burnishing tool according to claim 1 ,
wherein the frame comprising:
a frame body fitted to the mandrel from the outside and defining first through-holes for the balls to be fitted thereto, respectively; and
a frame cover fitted to the frame body from the outside, having the balls projecting radially outward from the outer peripheral surface of the frame, and defining second through-holes which coincide in position with the first through-holes for preventing the balls from dropping out of the first through-holes, respectively.
6. A dimple-forming burnishing method comprising: contacting the balls on the work surface to form dimples on the work surface using the dimple-forming burnishing tool according to claim 1 .
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2012-035752 | 2012-02-22 | ||
JP2012035752A JP5624570B2 (en) | 2012-02-22 | 2012-02-22 | Dimple molding burnishing tool and dimple molding burnishing method |
Publications (1)
Publication Number | Publication Date |
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US20130213106A1 true US20130213106A1 (en) | 2013-08-22 |
Family
ID=48915432
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/774,366 Abandoned US20130213106A1 (en) | 2012-02-22 | 2013-02-22 | Dimple-forming burnishing tool and dimple-forming burnishing method |
Country Status (5)
Country | Link |
---|---|
US (1) | US20130213106A1 (en) |
JP (1) | JP5624570B2 (en) |
KR (1) | KR101481005B1 (en) |
CN (1) | CN103286665B (en) |
DE (1) | DE102013202816B4 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170348821A1 (en) * | 2016-06-06 | 2017-12-07 | United Technologies Corporation | Deep roll peening system and method |
WO2019034314A1 (en) * | 2017-08-15 | 2019-02-21 | Robert Bosch Gmbh | Tool device for rolling a component bore, and method for operating the tool device |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11027341B2 (en) * | 2016-01-06 | 2021-06-08 | Kanefusa Kabushiki Kaisha | Dimple processing method using rotary cutting tool, and rotary cutting tool for dimple processing |
KR101927521B1 (en) * | 2016-12-16 | 2019-03-12 | 주식회사 금강 | Burnishing device with a spring with a maximized buffer |
Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1597212A (en) * | 1924-10-13 | 1926-08-24 | Arthur F Spengler | Casing roller |
US2375235A (en) * | 1941-05-15 | 1945-05-08 | Babcock & Wilcox Co | Apparatus for tube expanding |
US3242567A (en) * | 1963-01-26 | 1966-03-29 | Vyzk A Zkusebni Letecky Ustav | Device for finishing of surfaces by radial forming |
US3751781A (en) * | 1972-01-24 | 1973-08-14 | Amtel Inc | Adjustable burnishing tool |
US3818734A (en) * | 1973-05-23 | 1974-06-25 | J Bateman | Casing expanding mandrel |
US3911707A (en) * | 1974-10-08 | 1975-10-14 | Anatoly Petrovich Minakov | Finishing tool |
US4054976A (en) * | 1975-04-24 | 1977-10-25 | Wilhelm Hegenscheidt Gmbh | Combined precision boring and burnishing tool |
US5269164A (en) * | 1991-10-29 | 1993-12-14 | Samsung Electronics Co., Ltd. | Device for forming spiral groove on inner wall of cylindrical cavity |
US6543139B2 (en) * | 2000-05-11 | 2003-04-08 | Sankyo Seiki Mfg. Co., Ltd. | Machining tool for manufacturing radial bearings, and manufacturing apparatus and manufacturing method using the same |
JP2005288557A (en) * | 2004-03-31 | 2005-10-20 | Sugino Mach Ltd | Roller burnishing tool main body and roller burnishing tool |
JP2007301645A (en) * | 2006-05-09 | 2007-11-22 | Sugino Mach Ltd | Burnishing tool for forming dimple |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4841259Y1 (en) * | 1970-12-18 | 1973-12-03 | ||
JP3729517B2 (en) * | 1994-08-02 | 2005-12-21 | チッソ株式会社 | Polyolefin resin composition |
JP2990069B2 (en) * | 1996-06-25 | 1999-12-13 | 株式会社守屋鉄工所 | Burr smoothing device |
JP4051053B2 (en) * | 2004-07-12 | 2008-02-20 | 株式会社スギノマシン | Roller burnishing tool |
CN102116880B (en) * | 2009-12-30 | 2013-09-18 | 鸿富锦精密工业(深圳)有限公司 | Processing device |
JP5604214B2 (en) | 2010-08-06 | 2014-10-08 | 株式会社ダイナックス | Electric motor power unit with built-in friction clutch |
JP5221635B2 (en) * | 2010-12-27 | 2013-06-26 | 株式会社スギノマシン | Dimple forming burnishing tool |
-
2012
- 2012-02-22 JP JP2012035752A patent/JP5624570B2/en active Active
-
2013
- 2013-02-18 KR KR20130016831A patent/KR101481005B1/en active IP Right Grant
- 2013-02-21 DE DE102013202816.4A patent/DE102013202816B4/en not_active Expired - Fee Related
- 2013-02-21 CN CN201310055444.0A patent/CN103286665B/en active Active
- 2013-02-22 US US13/774,366 patent/US20130213106A1/en not_active Abandoned
Patent Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1597212A (en) * | 1924-10-13 | 1926-08-24 | Arthur F Spengler | Casing roller |
US2375235A (en) * | 1941-05-15 | 1945-05-08 | Babcock & Wilcox Co | Apparatus for tube expanding |
US3242567A (en) * | 1963-01-26 | 1966-03-29 | Vyzk A Zkusebni Letecky Ustav | Device for finishing of surfaces by radial forming |
US3751781A (en) * | 1972-01-24 | 1973-08-14 | Amtel Inc | Adjustable burnishing tool |
US3818734A (en) * | 1973-05-23 | 1974-06-25 | J Bateman | Casing expanding mandrel |
US3911707A (en) * | 1974-10-08 | 1975-10-14 | Anatoly Petrovich Minakov | Finishing tool |
US4054976A (en) * | 1975-04-24 | 1977-10-25 | Wilhelm Hegenscheidt Gmbh | Combined precision boring and burnishing tool |
US5269164A (en) * | 1991-10-29 | 1993-12-14 | Samsung Electronics Co., Ltd. | Device for forming spiral groove on inner wall of cylindrical cavity |
US6543139B2 (en) * | 2000-05-11 | 2003-04-08 | Sankyo Seiki Mfg. Co., Ltd. | Machining tool for manufacturing radial bearings, and manufacturing apparatus and manufacturing method using the same |
JP2005288557A (en) * | 2004-03-31 | 2005-10-20 | Sugino Mach Ltd | Roller burnishing tool main body and roller burnishing tool |
JP2007301645A (en) * | 2006-05-09 | 2007-11-22 | Sugino Mach Ltd | Burnishing tool for forming dimple |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170348821A1 (en) * | 2016-06-06 | 2017-12-07 | United Technologies Corporation | Deep roll peening system and method |
US10603761B2 (en) * | 2016-06-06 | 2020-03-31 | United Technologies Corporation | Deep roll peening system and method |
US11673227B2 (en) | 2016-06-06 | 2023-06-13 | Raytheon Technologies Corporation | Deep roll peening system and method |
WO2019034314A1 (en) * | 2017-08-15 | 2019-02-21 | Robert Bosch Gmbh | Tool device for rolling a component bore, and method for operating the tool device |
Also Published As
Publication number | Publication date |
---|---|
JP5624570B2 (en) | 2014-11-12 |
KR20130096652A (en) | 2013-08-30 |
CN103286665B (en) | 2015-07-15 |
JP2013169624A (en) | 2013-09-02 |
DE102013202816B4 (en) | 2019-10-02 |
CN103286665A (en) | 2013-09-11 |
KR101481005B1 (en) | 2015-01-09 |
DE102013202816A1 (en) | 2013-08-22 |
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Owner name: SUGINO MACHINE LIMITED, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FUTAMURA, MASARU;KAWASUMI, KATSUYUKI;MIYAUCHI, SHINYA;SIGNING DATES FROM 20130208 TO 20130211;REEL/FRAME:029860/0626 |
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STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |