JP3328313B2 - Adjustable boring bar - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to the field of tools such as boring bars, and more particularly to boring bars with adjustable cartridges. The boring bar includes a slot having a corresponding arcuate seating surface for seating the rounded or arcuate bottom surface of the anvil making up the cartridge. The boring bar also slides the anvil against the curved or arcuate seating surface of the slot of the boring bar against the biasing force (preload force) of the tension leaf spring, and the anvil and the Means are provided for pivoting the fixed cutting blade insert relative to the boring bar. Thus, the anvil is held in place by the tension generated against the tension leaf spring, thus eliminating the need for a set screw required in the prior art, as described below.

[0002]

U.S. Pat. No. 3,885,282 to Patakey describes a tool including a holder and an insert on which a cutting tool can be mounted. The insert is pivotally mounted in a recess in the holder and is secured in a desired position relative to the holder by a tightening screw. By adjusting the insert by rotating it, the working angle of the tip can be changed. U.S. Pat. No. 4,463,1994 to Jester et al. Describes a holder for a cutting tool that can be adjusted linearly and angularly. In such a tool, an adjusting screw having a threaded portion seated on a base element and a head portion for retaining a cutting tool insert, the head portion engaging a recess in a rotatably mounted receiving element. Pivot-like adjustment is possible. Turning the adjusting screw rotates the receiving element.
However, the arrangement described in each of the aforementioned U.S. patents is not intended to mitigate the problem of cumulative manufacturing tolerances. Furthermore, the high-speed boring bar, which has a conventional cartridge mounted around it, cannot meet the precision cutting parameters required today because of chattering. Although it is possible to stabilize the boring bar by forming a recess large enough to seat the cartridge inside the boring bar, the radial adjustment of the boring bar will depend on the adjusting force. In the case of a boring bar having a small diameter, the boring bar is warped because the pressing is performed on the boring bar.

Nogle US Pat. No. 4,927,301 describes a boring bar that addresses the aforementioned disadvantages of warpage and cumulative manufacturing tolerances. In that patent, an anvil-shaped cartridge is fitted inside a groove with a curved bottom surface of a boring bar. The anvil loosens the set screw and adjusts the anvil with an arced headed screw that presses the anvil against a spring washer held on another screw at the opposite end position of the anvil, and then when the anvil is in the desired position, Turning the set screw again locks it properly in its assembled state. According to the present invention, an improvement is provided over the above-mentioned U.S. Pat. No. 4,927,301. Tightening screws as well as spring washers are eliminated, so that the operating method is simplified to a one-step adjustment, thereby facilitating operation, eliminating set screws and substantially saving labor.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an adjustable insert cartridge recessed inside a boring bar, wherein the force required for radial adjustment of the insert cartridge deflects the boring bar. Providing an adjustable insert cartridge that is sub-optimal in size, providing an adjustable cartridge that is adequately addressed for high speed applications, and that is easy to adjust and requires tightening screws. It is to provide an adjustable cartridge that holds the cartridge in place without the need.

[0005]

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided an adjustable cartridge which is easily adjusted by turning a single screw on a rotatable boring bar. The boring bar has a longitudinally oriented slot or recess having a pair of parallel side walls spaced by the width of its curved arcuate seating surface. It is important that the seat (bottom) of the cartridge is completely in contact with the seating surface, or at least at two points. A disadvantage of the prior art was that the cartridge was often not seated at at least two points along the seating surface, thereby causing such boring bars to chatter in use. The seating surface intersects the side wall and opens radially on the outer peripheral surface of the boring bar. The cartridge comprises an anvil having a top surface and an arcuate bottom surface. The top surface has a concave pocket for receiving an indexable insert, the concave pocket being positioned between a front portion and a rear portion of the cartridge. The arcuate bottom surface of the anvil extends between the front and rear portions of the boring bar and abuts the corresponding arcuate seating surface of the recess of the boring bar when the anvil is seated in the slot. The front and rear portions are formed with recesses for receiving preload means for an anvil in the arcuate seating surface.

The cartridge is positioned axially spaced from its center of rotation on the anvil so that fine adjustments can be made and the load generated by the cutting operation is primarily transmitted to the boring bar. Thus, the inwardly directed cutting reaction force at the cutting blade of the insert places a load on the anvil and its adjusting means, not on the preloading means. An advantage of the present invention is that the loading effect using elastic preloading means is eliminated, thereby allowing for fine adjustment, while minimizing the chatter. Another benefit is that indexable inserts and adjustable cartridges can be provided within the boring bar without the need to significantly remove the boring bar material, thereby maintaining the strength of the boring bar. is there. Yet another benefit is that by rotating the anvil at the arcuate seating surface of the recess in the boring bar, adjustment means are not required to load the boring bar of small diameter enough to warp. That is. In addition, the benefits of the present invention include a set screw that penetrates the boring bar and abuts an adjustment screw to maintain the anvil in place, or a side wall of the recess or arcuate slot of the boring bar that passes the anvil. The cartridge can be adjusted within the arcuate slot and held in place without resorting to other means for holding against the abutment.

[0007]

Referring to the drawings, the boring bar 10 of the present invention is adapted to rotate about its longitudinal axis 12. The boring bar 10 is cylindrical in shape, as is well known, and has an outer peripheral surface 14 provided with at least one and optionally a plurality of axial slots or recesses 16 as required. . Each recess 16 has an arcuate seating surface 20 that opens radially toward the outer peripheral surface 14.
And parallel walls 18, 18 (see FIG. 5) rising from both sides thereof.

[0008] The adjustment cartridge (hereinafter simply referred to as "cartridge") 22 comprises an elongated anvil 24 formed of hard steel for tools. Anvil 24
It has a uniform width and axial dimension corresponding to the particular recess 16 selected. Cartridge 22 corresponds to the cartridge, the arcuate surface 27 of the recess 16 so that it can turn in the axial direction (see FIG. 6) in a clockwise or counterclockwise <br/> clockwise depending on the direction to be adjusted position It has a rounded or arcuate bottom surface 26.

The anvil 2 which is the main body of the cartridge 22
4 is for receiving a top surface 28 radially separated from the bottom surface 26 and a disposable indexable disposable cutting blade insert (exchangeable cutting blade or replacement blade) (hereinafter also simply referred to as “insert”) 32. It has at least one insert receiving pocket 30. The pocket 30 comprises a seating surface 36 and at least two abutment walls 34,
34 (FIG. 4). The seating surface 36 is formed with a screw hole 38 for receiving insert fixing means in the form of an insert holding screw 40. When the space and the weight around the workpiece are taken into consideration as the insert fixing means, I.I. S. O. Although standard screws are preferred, other securing means are available to those skilled in the art and can be used in the present invention with appropriate modifications.

Referring to FIGS. 6 and 7, the top surface 28 of the anvil 24 has an axially separated front portion 42 and a rear portion 44 separated by an insert 32. The above-described arc-shaped bottom surface 26 extends from the front portion 42 to the rear portion 44. In the rear part 44,
Adjust the cartridge 22 as will be described later, the first recess 46 to transmit motion from the cartridge regulating means 48 for providing counterclockwise rotation to adjust the insert 32 in the radial direction is formed. The range of this adjustment is at least as large as the cumulative manufacturing tolerances of the cartridge 22 and the boring bar 10, but the range of adjustment via the adjustment means 48 may be as large as 0.508 mm (0.020 in). preferable.

[0011] More particularly, the adjustment means 48 is threaded into the boring bar 10, with arcuate head capable of exerting a camming force contact with the anvil 24 in a circular cone surface 47 of the first recess 46 It consists of a tightening screw 50. Preferably, the tightening screw 50 is a right-hand thread having a fine pitch (eg, having 32 threads per 25.4 mm) to eliminate slippage. Prior art, especially U.S. Pat.
No fixing means for fixing the tightening screw 50 in place as in the case of the prior art disclosed in US Pat. This makes it easier for the operator to adjust the anvil 24 and eliminates the need for the extra operation of fixing the screw 50 in place with the set screw.
Is clearly an advantage in that one can be sure that is held in place. Avoiding the need for such a set screw is advantageous in that it is not necessary to inscribe a threaded hole for receiving the set screw in the side wall of the boring bar 10 in a direction transverse to its axis of rotation 12; Considerable savings are also made in terms of cost, and since the extra screw holes are not cut, the strength of the boring bar 10 is increased, and the adjustment operation is simplified, so that labor costs are also saved.

A second recess 52 is formed in the forward portion 42 of the top surface 28 of the anvil 24 and, if desired, a transverse spring receiving pocket 56 is provided in the recess 52, and the spring receiving pocket 56 is provided with a dowel pin. 54 can be inserted. In the present invention, means are provided for applying a preload to the anvil 24 in the recess 16 during the adjusting operation, as shown in FIGS. This preliminary load applying means,
The leaf spring 60 is pressed against the second recess 52 so as to be pressed, and the recess 17 is provided on the outer peripheral surface 14 of the boring bar 10.
And a screw 58 screwed into the floor 62. The recess 17 and the recess 52 are adapted to receive the leaf spring 60 and have both side walls substantially parallel to each other and also parallel to the axis of rotation of the bore (see also FIGS. 1 and 2). Leaf spring 60
Are held in pressure contact with the anvil 24 in the recesses 52 and apply an elastic preload to the anvil 24. The optional dowel pin 54 includes a leaf spring 60
With a rolling surface. When the dowel pins 54 are not provided, the plate spring 60 abuts directly on the bottom surface of the recess 52.

The disposable insert 32 is typically formed from a sheet of hardened material such as, for example, tungsten carbide, ceramic or sialon. Desirable materials will vary depending on the intended use and boring operating conditions. For example, the diameter disclosed herein is 53.975 mm and the length is about 81.
When using five adjustment cartridges in a 2.8 mm boring bar and boring a soft abradable material such as cast iron, the 9.525 mm sold by GTE Valenite Corporation. × 11.6
84mm parallelogram tungsten carbide VC-
Two-piece inserts are used. When boring a carbon steel material, an insert made of tungsten carbide VC-5 can be used. Further, depending on the application, inserts having various positive or negative radial rake angles and positive or negative axial rake angles may be used. For example, when boring a carbon steel material, it is preferable to use a parallelogram insert having a positive radial rake angle and a positive axial rake angle. When boring a material such as cast iron, an insert having a negative radial rake angle and a negative axial rake angle is used. It will be apparent to those skilled in the art that the size of the radial rake angle and the axial rake angle will depend on various variable factors, including the specifications of the workpiece to be machined.

The position of the insert 32 and insert receiving pocket 30 on the top surface 28 of the anvil is important in obtaining the adjustment range described above. When the anvil 24 is turned within the recess 16, it is turned about the anvil center axis 64 (FIG. 4) when not restrained by the preloading means 60 or the cartridge adjusting means 48. When the insert 32 and pocket 30 are axially positioned from the central axis 64 toward the front portion 42 of the anvil, the closer the pocket 30 is to the central axis 64, the smaller the adjustable range. The exact location of the insert 32 within the anvil 24 will also depend, in part, on the size of the insert and the anvil, but in general, the closer the pocket 30 is to the central axis 64, the greater the load applied during the operation. It will be apparent to those skilled in the art that it is absorbed by the boring bar 10 itself, rather than by the preloading means or cartridge adjustment means. Therefore, chattering (rattle) of the cartridge during operation is reduced, and wear of the cartridge is reduced.

In the prior art, a plurality of screw holes for screwing a set screw for pressing the anvil 24 against one side wall of the recess 16 are formed at right angles to the side wall of the recess of the boring bar 10. However, the opening has to be provided in the outer peripheral surface 14 of the boring bar 10 so that the operator can touch it. However, the present invention eliminates the need to provide such a plurality of screw holes for set screws. . Therefore, the work of mounting the anvil is simplified, and the machining cost for manufacturing the boring bar is reduced.

In use, adjustment of the radial position of the insert 32 is accomplished by turning the screw 50 and engaging the arcuate head 51 of the screw 50 with the first recess 46 in the rear portion 44 of the anvil 24.
This can be performed quickly by pressing against the conical surface 47. At this time, the cam acting force generated between the head 51 and the first recess 46 drives the anvil 24 along the arcuate seating surface 20 of the recess 16 from the position in FIG. 6 to the position in FIG. , Rotate in the desired direction. As a result, the cutting blade of the insert 32 axially spaced from the center axis 64 of rotation of the anvil is radially displaced from a radial distance d to d1. When the rotation of the screw 50 is stopped at a desired adjustment point, the preload applying means (leaf spring 60) automatically holds the anvil 24 at a predetermined position. No screws or other means are required.

[0017]

The loading effect of the resilient preloading means is eliminated, thereby minimizing chattering while allowing for fine adjustment, the indexable insert and the adjustable indexable insert. Tool strength is maintained by the cartridge being provided in the boring bar without significant removal of the bar, and the boring bar is provided with a diameter by turning the anvil at the bottom of the boring bar. Small boring bars do not require adjustment means to load the warp as much as warpage occurs, and furthermore, the cartridge may need an adjusting screw or screw to penetrate the boring bar and maintain the anvil in place. Without relying on tightening screws to abut the other means to properly maintain the anvil in contact with the side walls of the recess;
It can be adjusted in the arcuate slot and held accordingly.

Although the present invention has been described with reference to embodiments, the present invention is not limited to the structure and form of the embodiments illustrated herein, but departs from the spirit and scope of the present invention. Rather, it should be understood that various embodiments are possible and that various changes and modifications can be made.

[Brief description of the drawings]

FIG. 1 is a perspective view of a boring bar of the present invention including at least one adjustable cartridge.

FIG. 2 is a partially enlarged plan view of a boring bar shown in FIG. 1;

FIG. 3 is a side view of the boring bar shown in FIG. 2;

FIG. 4 is an exploded perspective view of the boring bar cartridge shown in FIG. 2;

FIG. 5 is a cross-sectional view of the boring bar shown in FIG. 3 taken along line 5-5.

FIG. 6 is a cross-sectional view of the boring bar of FIG. 2 taken along line 6-6, showing the preloading means under tension.

FIG. 7 is a cross-sectional view of the boring bar of FIG. 2 taken along line 6-6 in a state where the load is released from the preloading means.

[Explanation of symbols]

 10: Boring bar 12: Center rotation axis 14: Outer peripheral surface 16: Slot or recess 18: Parallel side wall 20: Arc-shaped seating surface 22: Cartridge 24: Anvil 26: Arc-shaped bottom surface 28: Top surface 30: Pocket 32 : Insert 42: front part 44: rear part 46: first recess 47: conical surface 48: cartridge adjusting means 50: fastening screw 51: arc head 52: second recess 54: dowel pin 58: screw 60: leaf spring 64 ： Center axis (center point)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23B 29/034

Claims (9)

(57) [Claims] 1. A boring bar assembly comprising: (a) rotatable about a central axis of rotation;
At least one of an arcuate seating surface radially open on the outer peripheral surface and a pair of axial walls parallel to each other and rising from both sides of the seating surface and parallel to the central rotation axis. A generally cylindrical boring bar body with two recesses, and (b) an adjustable cartridge received in the recess, the cartridge having a generally flat top surface and an arcuate shape of the recess. An anvil having an arcuate bottom surface cooperating with a seating surface to define a rotational adjustment path; and a pocket on the top surface of the anvil for receiving an indexable polygonal insert. Has an axially spaced forward and rearward portion, the arcuate bottom surface extending from the forward portion to a rearward portion, the rearward portion for receiving cartridge adjustment means. Having a first recess, wherein the front portion is A second recess for receiving the heavy application means, said second recess is configured to leaf spring holding portion
That are parallel to each other and to the axis of rotation.
A recess having a pair of side walls, for the leaf spring.
A dowel pin acting as a pivot point traverses the recess
Are disposed Te, said insert has a cutting edge which is seated within said anvil, the cutting blade gives a rotational force around the center point boring work in the anvil, the (C) cartridge adjustment means for adjusting the cartridge in the boring bar body along the adjustment path, wherein the cartridge adjustment means is axially spaced from the center point to exert a load on the cartridge adjustment means; (D) preloading means for applying a preload to the anvil so as to press the anvil against the cartridge adjusting means within the recess, wherein Before being fixed to the boring bar body and extending into the second recess and pressing against the anvil
Boring bar assembly, characterized by having said preload applying means composed of a serial leaf spring. 2. The cartridge adjusting means is screwed into the boring bar main body, abuts on a rear portion of the anvil, and drives the anvil counterclockwise along the seating surface. The boring bar assembly according to claim 1, further comprising a screw for adjusting the radial position of the cutting blade. 3. The cutting blade according to claim 2, wherein said cutting blade has a neutral axial rake angle and a positive radial rake angle.
The boring bar assembly of claim 1 . 4. The rear portion of the anvil has a conical surface for abutting the screw.
Boring bar assembly according to 3. 5. The apparatus according to claim 5, wherein the cartridge adjusting means is about 0.5.
5. The boring bar assembly of claim 4 , wherein the boring bar assembly allows a radial adjustment range of 0.020 inches. 6. A boring bar assembly, wherein the boring bar assembly is rotatable about a central rotation axis, and has an outer peripheral surface, an arc-shaped seating surface radially opened in the outer peripheral surface, and both sides of the seating surface. A generally cylindrical boring bar body having at least one recess having a pair of axial walls parallel to each other and parallel to the central axis of rotation rising from the recess; and a adjustable cartridge to be received, the cartridge consists of an anvil having a substantially flat top surface, a circular arc bottom that will be movably supported in the arcuate seat wear surface, the top surface of the anvil Has a pocket for receiving an indexable polygonal insert, and a front portion and a rear portion separated by the pocket and axially separated, the arcuate bottom surface extending from the front portion to the rear portion. And the rear part extends forward. A first recess for receiving a cartridge adjusting means for adjusting the position of the cartridge with respect to the boring bar main body, wherein the anvil includes a preload applying means for applying a preload to the anvil in the recess. the second has a recess for receiving said first
The two recesses constitute a leaf spring holding portion, and
And a recess having a pair of side walls parallel to the axis of rotation
And serves as a pivot point for the leaf spring
A dowel pin is disposed across the recess, the insert having a cutting blade seated in the anvil, the cutting blade centered on the anvil during boring. The cartridge adjusting means is screwed into the boring bar main body, and abuts on the rear portion of the anvil to provide the anvil. Comprises a screw for driving the insert in a counterclockwise direction along the arcuate seating surface and thereby adjusting the radial position of the insert, wherein the preloading means comprises a second recess of the anvil. a screw is screwed into the boring bar tool at a position close to, and characterized in that it consists of said plate spring being pressed against the anvil extends is fixed at a predetermined position the second recess by the screw While Ri bar assembly. 7. The cutting blade according to claim 1, wherein said cutting blade has a neutral axial rake angle and a positive radial rake angle.
7. The boring bar assembly according to 6 . 8. The boring bar assembly according to claim 6 , wherein the first recess has a conical surface for abutting the screw. 9. The cartridge adjusting device according to claim 8, wherein
7. The boring bar assembly according to claim 6 , wherein the boring bar assembly allows a radial adjustment range of 0.020 inches.