JPH0727077Y2 - Center polishing tool - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center polishing tool used for polishing a center hole provided at both end shaft centers of a rotor-shaped workpiece used for grinding or the like.

[0002]

2. Description of the Related Art Generally, when grinding the outer periphery of a rotary body with a cylindrical grinder, the spindle center and tailstock center support the workpiece rotatably at both ends, and the spindle center does not rotate. The work is rotated by a rotary drive plate fitted onto the main shaft via a clamp mechanism such as a scraper, and a rotary grindstone is brought into contact with the peripheral surface of the work to perform grinding. Thus, in supporting the work between the centers as described above, a center hole having a conical peripheral surface for fitting the conical tip portions of the centers in advance at the axial center positions of both end surfaces of the work. Is formed. The cone angle of this center hole is usually set to 60 degrees.

In this grinding process, even if the center of the center hole of the work is slightly deviated from the center of the work, the large radius side is first cut due to the deviation in the process of cutting the work by rotating the work around the center hole. Therefore, as a result, the shaft center after grinding coincides with the center hole. However,
If the circularity of the center hole is incorrect, the rotation axis of the workpiece during grinding is not constant, and the circularity of the outer circumference to be cut due to runout or one-sided contact does not occur, resulting in a significant decrease in cutting accuracy. Will be invited.

However, the center polishing machine conventionally used for polishing after the drilling of the center hole has a mechanism of cutting into the inner circumference of the hole by the helical motion of eccentric rotation while the main shaft rotates. Since the polished surface has an elliptical shape and structural eccentricity unevenness and rotation unevenness are likely to occur, it is difficult to obtain a center hole with high roundness.

Therefore, the inventors of the present invention have previously made a practical application in Japanese Patent Application No. 3-1.
As No. 13340, a non-rotating spindle center and tailstock center having conical tip portions that fit into center holes at both ends of the workpiece, a rotary drive plate rotatably fitted on the spindle center, and the workpiece are A pressing means for pressing in the axial direction and a work clamping means for clamping the work to rotate integrally with the rotary drive plate are provided, and the surfaces of the conical tips of the both centers form a grindstone surface. There is proposed a center polishing apparatus configured to polish the center hole by rotating the work supported by.
Therefore, according to this center polishing apparatus, the center holes provided at the shaft centers of both ends of the work to be ground can be set to have an extremely high roundness.

[0006]

However, in the above-mentioned proposed center polishing apparatus, the center whose surface of the conical tip portion is the grindstone surface is used as a non-rotating polishing tool to rotate the center hole by rotating the work side. Since the above-mentioned grindstone surface is generally formed by depositing abrasive grains such as diamond or borazon by an electrodeposition method or the like, even if the center hole has a high roundness, abrasion of the abrasive grains on its inner peripheral surface is performed. There is a drawback that the marks are likely to remain in a line along the circumferential direction.

In view of the above situation, the present invention makes it possible to set the center hole provided at the axial center of both ends of a workpiece to be ground or the like to have an extremely high roundness, and the inner peripheral surface of the center hole to be scratched by abrasive grains. It is an object of the present invention to provide a center polishing tool that can achieve a beautiful finished state with no defects.

[0008]

In order to achieve the above object, a center polishing tool 1 according to claim 1 of the present invention has a tapered cone portion 2a having a front portion fitted into a center hole H of an end face of a workpiece W, and an intermediate portion. The tool has a ring holding portion 3b, a tool body 2 having a shank portion 2c whose rear portion is fitted to the non-rotating main shaft 13, and an engaging portion 3 for the rotary drive plate 14 which is externally fitted to the non-rotating main spindle 13, A rotary cam ring 4 that is rotatably and axially immovably fitted to the outside of the ring holding portion 2b of the main body 2, and a front side of the ring holding portion 2b that is in contact with the rotary cam ring 4 in the axial direction. A non-rotating cam ring 5 that is movably and non-rotatably fitted on the outside and a plurality of split grooves 6a to 6c that are axially cut from both ends are provided, and the taper cone portion 2a of the tool body 2 is forcibly expanded in diameter. On the large diameter side The non-rotating cam ring 5 includes a tapered sleeve 6 which is fitted in the non-rotating cam ring 5 so as to be axially movable and non-rotatable. The rotating cam ring 4 and the non-rotating cam ring 5 have mutually opposed end surfaces 4a and 5a corresponding to each other. The taper sleeve 6 is formed into a cam shape that moves in and out in the axial direction, and the outer peripheral surface of the taper sleeve 6 constitutes a grindstone surface 7, and the tool body 2 urges the taper sleeve 6 axially rearward by a spring force. The pullback means 7 to 9 are provided.

According to a second aspect of the present invention, in the center polishing tool 1 according to the first aspect, the tool body 2 has a cylindrical shape,
The pulling-back means is composed of shaft bodies 8 and 9 loaded in the center hole 11 of the tool body 2 and a coil spring 10 that pulls the shaft bodies 8 rearward in the axial direction, and the shaft body 8 projects outward from the center hole 11. A structure is adopted in which the front end has a flange portion 8a that comes into contact with the end surface of the taper sleeve 6 on the small diameter side.

[0010]

The center polishing tool 1 is mounted on the non-rotating main shaft 13 of the center polishing apparatus 12, and the front end portion of the truncated cone in which the taper sleeve 6 of the center polishing tool 12 is fitted is fitted into the center hole H of the work W which has been pre-drilled. When the work W is rotated by the rotation drive plate 14 fitted onto the non-rotating main shaft 13, the center polishing tool 1 does not rotate, so that the grindstone surface 7 on the outer peripheral surface of the taper sleeve 6 is the center of the work W. The center hole H is polished by sliding contact with the inner surface of the hole H. At this time, the rotary cam ring 4 of the center polishing tool 1 is also rotated by the rotary drive plate 14 via the engaging portion 3, and the non-rotary cam ring 5 contacting this with the cam surface reciprocates in the axial direction, and taper in the forward progression thereof. Sleeve 6
Is pushed forward and is pulled backward by the pullback means in the backward stroke, so that the grindstone surface 7 makes sliding contact with the inner surface of the center hole H of the rotating work W while reciprocating in the axial direction. When 6 is pushed forward, the diameter of the split grooves 6a to 6c is reduced by reducing the groove width, so that the diameter of the contact portion with the center hole H is kept constant even when reciprocating.

Therefore, in this polishing, the center itself that supports the work W serves as a grindstone, and the work W rotates around the center where the shaft center does not move, and there is no wobbling of the polishing shaft.
The polished center hole H has an extremely high roundness, and since the grindstone surface makes sliding contact while relatively rotating in the circumferential direction and reciprocating in the axial direction, a clean polished surface without abrasive marks of the abrasive grains is obtained. can get.

Further, since the basic structure of the center grinding device to which the center grinding tool 1 is applied may be the same as that of the cylindrical grinding machine, only the spindle center of the ordinary cylindrical grinding machine is replaced by the center grinding tool 1 of the present invention. The center hole of can be polished. Therefore, the existing cylindrical grinder can be used as it is as a center polishing apparatus. The outer peripheral surface of the taper sleeve 6 may be the grindstone surface 7 by applying abrasive grains such as diamond or borazon to the outer peripheral surface by an electrodeposition method or the like.

Although there are no particular restrictions on the means for pulling back the taper sleeve 6, the tool body 2 has a cylindrical shape, and the shaft bodies 8 and 9 are provided in the center hole 11 of the tool body 2 and the coil spring 10 for pulling the shaft bodies 8 rearward in the axial direction. And a flange portion 8a provided at the front end of the shaft body 8 projecting outward from the center hole 11.
According to the method of abutting against the end surface of the taper sleeve 6 on the small diameter side, the mechanism and structure are simple and high operation reliability can be obtained.

[0014]

1 and 2 show a center polishing tool 1 according to an embodiment of the present invention. The center polishing tool 1 has a tapered cone portion 2a having a truncated cone shape in the front portion, a ring holding portion 2b in the middle portion, a tapered shank portion 2c in which the rear portion is slightly reduced in diameter toward the rear end, and has a central hole 11. The cylindrical tool body 2, the rotary cam ring 4 externally fitted to the rear side of the ring holding part 2b, the non-rotating cam ring 5 externally fitted to the front side of the ring holding part 2b, and the tapered cone part 2a. The taper sleeve 6 fitted in the sleeve, the shaft bodies 8 and 9 and the coil spring 10 loaded in the center hole 11, and the center hole 11
It is composed of a plug body 15 screwed to the rear end.

As shown in FIG. 3, the rotary cam ring 4 has a cam shape in which the front end surface 4a moves in and out in the axial direction (a two-wave cam surface in which unevenness continuously changes with a phase difference of 90 degrees along the circumferential direction). The inner peripheral surface is provided with an annular groove 16a having a semicircular cross section, and the outer surface is provided with two engaging rods 3 and 3 protruding in a substantially radial direction in parallel with each other through a screw portion 3a. The ring holding portion 2b of the tool body 2 via a plurality of rotation balls 17 loaded in an annular space 16 having a circular cross section constituted by the annular groove 16a and a similar annular groove 16b on the tool body 2 side. It is held rotatably and immovably in the axial direction. Reference numeral 18a is a stopper for closing the ball loading hole 18b.

As shown in FIG. 3, the non-rotating cam ring 5 is formed in a cam shape in which a rear end surface 5a thereof moves in and out in the axial direction corresponding to the front end surface 4a of the rotating cam ring 4, and has an annular recess on the inner peripheral edge on the front end side. The rotary cam ring 4 has a step portion 5b, and the notch portion 15c provided in the annular recessed step portion 5b is engaged with the locking pin 19 planted on the tool body 2 side.
And the cam-shaped opposed end surfaces 4a and 5a are in contact with each other,
It is held by the ring holding portion 2b of the tool body 2 so as not to be rotatable and axially movable.

The taper sleeve 6 has a truncated cone shape whose outer shape is similar to the taper cone portion 2a of the tool main body 2, and each of which has a plurality of long split grooves 6a which are cut in the axial direction alternately from both end surfaces on the small diameter side and the large diameter side. 6b and short split grooves 6c which are alternately cut axially from the end surface on the large diameter side for each pair of both split grooves 6a, 6b, and the outer peripheral surface constitutes a grindstone surface 7 formed by electrodeposition of abrasive grains. In the natural state, the maximum inner diameter on the large diameter side is set to be slightly smaller than the base outer diameter (maximum diameter) of the tapered cone portion 2a. Then, this taper sleeve 6
Is a plurality of crescent plate-shaped keys 2 embedded in the taper cone portion 2a of the tool body 2
0 (see FIG. 3) is fitted into each split groove 6a, and the tapered cone portion 2 is fitted by being fitted in a state where the diameter is forcibly expanded.
It is held non-rotatably and axially movable on a.
In this fitted state, the peripheral end of the taper sleep 6 on the large diameter side is set so as to be able to contact the annular recessed step portion 5b of the non-rotating cam ring 5.

The shaft body 8 is provided with a flange portion 8a at the front end protruding from the center hole 11 of the tool body 2, and the flange portion 8a is provided.
Engages with the peripheral end of the taper sleep 6 on the small diameter side,
The shaft body 8 and the shaft body 9 are integrally connected by screwing the latter male screw portion 9b into the former female screw portion 8b, and the annular step portion 9a provided on the outer periphery of the rear portion of the shaft body 9 and the tool body 2 The coil spring 10 loaded in a compressed state between itself and the annular stepped portion 11a provided in the center hole 11 of the two shafts 8, 9
Is pulled backward in the axial direction. Therefore, the taper sleep 6 is always urged so that the peripheral end on the large diameter side is in contact with the annular recessed step portion 5b of the non-rotating cam ring 5, and when the rotating cam ring 4 rotates, it does not rotate with the rotating cam ring 4. The cam ring 5 reciprocates in the axial direction within a stroke S in which the position where the cam surfaces of the cam rings 5 are in close contact with each other is the withdrawal limit and the position where the convex portions of both cam surfaces are in contact with the advance limit.

FIG. 4 shows a center polishing apparatus 21 using the above center polishing tool 1, which has the same basic structure as a cylindrical grinding machine. In the figure, 21a is a machine base, 22 is a headstock, 2
Reference numeral 3 denotes a tailstock movably provided along a guide bar 24 on the machine base 21a, and the cylindrical non-rotating main spindle 13 of the headstock 22 has the above-described center grinding instead of the normal spindle center. A tool 1 is mounted, and a tailstock center 25 is mounted on the tailstock 23 via a cylindrical center holder 26 so as to be opposed to the tool 1 coaxially.

As shown in FIG. 5, on the outer periphery of the front portion of the non-rotating main shaft 13, a pulley 27a having a ring-shaped rotary drive plate 14 fixed to the front surface is rotatably fitted via a bearing 28. The pulley 27a is adapted to rotate in conjunction with the transmission belt 30 as the pulley 27b driven by a motor 29 mounted on the headstock 22 rotates. Further, a drive pin 31 is provided on the outer peripheral side of the front surface of the rotary drive plate 14, and the drive pin 31 is arranged between the locking rods 3 provided on the rotary ring 4 of the center polishing tool 1. There is. Reference numeral 32 is a cover that covers both pulleys 27a and 27b and the front side of the pulley 27b, and 33 is a seal ring that seals a gap between the non-rotating main shaft 13 and the rotary drive plate 14.

On the other hand, the center holder 26 of the tailstock 23
Is arranged so as to axially move through an air cylinder 34 provided at the rear of the tailstock 23 and is integrated with the piston of the air cylinder 34. Reference numeral 35 is a clamp lever for fixing the tailstock 23 at a required position on the guide bar 24. In addition, the non-rotating main shaft 13 and the rear end of the center holder 26 have a handle 3 for extracting the center.
6, 36 are screwed in, and by rotating these handles 36 in the approach direction, the center polishing tool 1 and tailstock center 25 can be ejected forward by the knockout pins 36a. .

Reference numeral 37 is a tool for clamping the work W. As shown in FIG. 6, two bolt-shaped support pins 38, 38 are equally arranged at three circumferential positions of the circular ring 37a.
A pressing lever 39 rotatable about a pivot 37b is attached, and a rotation transmitting pin 40 is provided on the outer periphery of the ring 37a so as to project. Then, the pressing lever 39
Is constantly urged by a spring 41 so that the cam-shaped inner end portion 39a thereof projects toward the inside of the ring. 39
Reference numeral b is a stopper pin that determines the rotation limit position of the pressing lever 39 in the biasing direction.

In the above structure, the center hole H of the work W
In the case of performing the polishing of the work W, first, scrape 3
Insert 7 This operation may be performed by rotating the pressing lever 39 as shown by the phantom line in FIG. 6 to externally fit the ring 37a to the work W and returning the lever 39 when the projecting amount of the inner end portion 39a becomes small. By the inner end 39a of the lever 39 and the inner ends of the support pins 38, 38, the work W is
Are clamped from three directions. In this case, the protrusion amounts of the support pins 38, 38 are adjusted according to the outer diameter of the work W.

Next, the center polishing tool 1 and the tip of the tailstock center 25 are fitted into the center holes H of both ends of the work W to support the work W, and the rotation transmission pin 37 of the breaker 37 is attached to the rotation drive plate 14. The tailstock center 25 is elastically pressed against the work W by the air cylinder 34 while being engaged with the rotary drive pin 31 of FIG. Then, the motor 29 of the headstock 22
Is driven, the pulley 27b rotates, and in conjunction with this, the rotary drive plate 14 rotates integrally with the pulley 27a, and the rotary drive pin 31 rotates the work W via the tool 37 and at the same time the center polishing tool 1 is rotated. The rotating cam ring 4 is also rotated, and accordingly, the non-rotating cam ring 5 and the taper sleeve 6 reciprocate in the axial direction at a rate of twice per rotation of the rotating cam ring 4, so that the center hole H of the workpiece W is tapered. And is brought into sliding contact with the grindstone surface 7 and is polished.

During the polishing, since the center axes of the center polishing tool 1 and the tailstock center 25 are immovable, the polishing shaft is also maintained in a fixed position accurately without any change until the polishing is completed. Work W is always driven by the urging of the cylinder 34
While pressing, project forward according to the polishing amount
Appropriate pressure is always applied to the polishing surface, and the grinding stone surface 7 slides in contact with the circumferential rotational movement and the axial reciprocating movement to exert a polishing action. Therefore, the center hole H after polishing has a very high roundness and is in a beautiful finished state without scratch marks of the abrasive grains, and when the outer periphery of the work W is ground by a cylindrical grinding machine, runout, one-sided contact, It is possible to achieve high processing accuracy without rattling.

The rotary drive plate 14 of the rotary cam ring 4
The engaging portion with respect to can adopt various structures other than the engaging rod 3 as in the above-mentioned embodiment, and the cam shapes of the facing end surfaces of the rotating cam ring 4 and the non-rotating cam ring 5 are not limited to the exemplified two-wape type. It can be set to 1 wave or 3 waves or more. In addition, in the present invention, the taper sleeve 6
Of the pull-back means, detailed shapes of the cam rings 4 and 5 and the taper sleeve 6, and a mounting structure for the tool main body 2 for enabling or disabling these members to rotate or move in the axial direction. The design can be changed. Further, the center grinding tool of the present invention can be applied to a cylindrical grinding machine having a detailed configuration different from the illustrated one, and a center grinding device having a non-rotating main shaft and a rotary drive plate which do not belong to the cylindrical grinding machine. Needless to say.

[0027]

According to the center polishing tool of the first aspect of the present invention, the center hole provided at the shaft center of both ends of the work to be ground or the like has a very high roundness and the abrasive grains are scraped. It can be finished in a very smooth state without traces, so that when performing polishing processing by supporting the polished work with center holes at both ends, there is no runout, one-sided contact, rattling, etc. High processing accuracy can be obtained. Further, since the center polishing apparatus to which this center polishing tool is applied has the same basic configuration as that of the cylindrical grinding machine, the above center polishing is performed only by mounting the center polishing tool instead of the spindle center in the ordinary cylindrical grinding machine. Therefore, there is an advantage that the existing cylindrical grinder can be used for center polishing without any modification.

According to the second aspect of the present invention, there is an advantage that the center polishing tool described above can be provided at a low cost, in particular, one having a simple mechanism and structure and having high operation reliability.

[Brief description of drawings]

FIG. 1 is a semi-longitudinal side view of a center polishing tool according to an embodiment of the present invention.

FIG. 2 is a front view of the polishing tool.

FIG. 3 is an exploded perspective view of a tool body, a rotating cam ring, and a non-rotating cam ring of the polishing tool.

FIG. 4 is a front view showing an example of a center polishing apparatus to which the polishing tool is applied.

FIG. 5 is a vertical sectional front view of the headstock side of the center polishing apparatus.

FIG. 6 is a vertical cross-sectional view showing a clamped state of a work piece due to the scraping of the center polishing apparatus.

[Explanation of symbols]

 1 Center polishing tool 2 Tool body 2a Tapered cone part 2b Ring holding part 2c Shank part 3 Engaging rod (engaging part) 4 Rotating cam ring 4a Front end face (cam end face) 5 Non-rotating cam ring 5a Rear end face (cam end face) ) 6 taper sleeve 6a split groove 6b split groove 6c split groove 7 grindstone surface 8 shaft body 8a flange portion 9 shaft body 10 coil spring 11 center hole 13 non-rotating main spindle 14 rotary drive plate 21 center polishing device 22 headstock 23 tailstock W Work H Center hole

Claims (2)

[Scope of utility model registration request] 1. A tool main body having a taper cone portion having a front portion fitted in a center hole of a work end surface, a middle portion having a ring holding portion, and a rear portion having a shank portion for being fitted into a non-rotating spindle, and an outer portion of the non-rotating spindle. Equipped with an engaging portion for the rotary drive plate to be fitted,
A rotary cam ring rotatably and axially immovably fitted on the rear side of the ring holding part of the tool body, and axially movable on the front side of the ring holding part in contact with the rotary cam ring. A non-rotating cam ring that is fitted non-rotatably and a plurality of split grooves that are axially cut from both ends are provided, and in the state where the diameter is forcibly expanded, the taper cone portion of the tool body is provided with a large-diameter peripheral end. A cam shape that comprises a taper sleeve that comes into contact with the non-rotating cam ring and is axially movable and non-rotatably fitted so that mutually facing end faces of the rotating cam ring and the non-rotating cam ring correspond to each other in the axial direction. In addition, the taper sleeve has an outer peripheral surface forming a grindstone surface, and the tool body is provided with a retracting means for urging the taper sleeve axially rearward by a spring force. Polishing tool. 2. The tool body has a cylindrical shape, and the pulling-back means is composed of a shaft body loaded in the center hole of the tool body and a coil spring for pulling the shaft body rearward in the axial direction, and the center hole of the shaft body. 2. The center polishing tool according to claim 1, wherein the front end protruding further outward has a flange portion that comes into contact with the end surface on the small diameter side of the tapered sleeve.