Patent Grant
9656365
The present invention relates to an improved honing tool and method, and more particularly to a means for moving the honing stoning radially during the honing process.
Prior methods of honing require the oscillation and rotation of the honing head to advance in a stepwise fashion as the honing stones are advanced or retracted. This reduced machine throughput potential, and limits process control means.
It would be an advance in the art to have a simple convenient way to move the honing stone positions continuously while material is removed in the honing process and appropriate control means during such a process to avoid excess material removal.
In the present invention, the first object is achieved by providing a rotary machining tool comprising a rotating magnetic coupling having a first cylindrical bore, a drive axle having a first primary cylindrical axis and work tool end and a driving end opposite the work tool end, wherein the drive axle is supported by one or more rotary couplings in the rotating magnetic coupling, an inner axle having a second primary cylindrical axis disposed concentrically within at least a portion of the drive axle, wherein the inner axle is supported by one or more rotary couplings in the drive axle, in which the first and second primary cylindrical axis are co-incident with a geometric center of the cylindrical bore, a magnet coupling means having a portion attached to the outer periphery of the inner axial that is operative co-rotate the inner axle with the external rotation of the magnetic coupling, a tool head coupled to the working tool end of said drive axle, said tool head having a third primary cylindrical axis and comprising, a plurality of abrasive member tangential spaced apart about the third cylindrical axis, each abrasive member coupled to a radial positioning means for radial position adjustment from at least partially within the tool head to beyond an outer periphery of the tool head, at least one drive means for coupling torque from the inner axle to the radial positioning means.
A second aspect of the invention is characterized by each of the honing stones is set in a gear driven support member which is geared to advance or retract in the radial direction with respect to the third cylindrical axis, and the radial positioning means is a pinion gear drive coupled to the inner axial that urges the simultaneous drive of the geared support members when the inner and out axle rotate at different speeds.
Another aspect of the invention is characterized by the rotary machining tool having a magnet coupling means further comprises a first plurality of magnets disposed about the inner periphery of the first cylindrical bore, wherein the magnets in said plurality are arranged with opposing polarity to each adjacent magnets and the portion of the magnet coupling means attached to the outer periphery of the inner axial is a second plurality of magnets, wherein the magnetic in the second plurality are arranged with opposing polarity to each adjacent magnet in the second plurality.
The above and other objects, effects, features, and advantages of the present invention will become more apparent from the following description of the embodiments thereof taken in conjunction with the accompanying drawings.
Referring to
In accordance with the present invention, a honing tool 100 has a rotary magnetic coupling 110, which contains a rotating drive axle 120, as well as a concentrically disposed inner axle 130. The rotating drive axle 120 is connected to the tool head 140. Pluralities of spaced apart abrasive or sharpened cutting members 145 are disposed about the circumferential direction of the tool head 140. The abrasive/cutting members 145 are commonly referred to as honing stones, and can be adjusted in the radial displacement from the central cylindrical axis 101.
Typical mechanism for adjustment of the abrasive members 145 in a honing tool are disclosed in U.S. Pat. Nos. 2,439,117; 3,216,155 and 4,524,549, which are incorporated herein by reference. One or more honing stones 145 can be set in tangentially spaced apart in mounts that are driven by a linear gear 137 that engages the pinion gear 135. The direction of rotation of the inner axle 130 thus directs the direction of travel of the linear gears 137 to drives the honing stones 145 inward away from the work piece 10, our outward toward the work piece 10, which can then continues to expand the bore hole concentrically. The rotating drive axial oscillates in the axial direction (arrow 102) as it rotates to complete the honing process. In the former case, retracting the honing stones 145 permits the removal of the tool head 140 from the completed bore hole formed in a work piece 10. These various drive mechanisms deploy some sort of pinion gear 135 that rotates with the inner axle 130 when the drive axle 120 is stationary. In conventional technology, the inner axle is activated via a clutch and slip rings, which requires stopping the drive axle 120 rotation.
The magnetic coupling 110 provides the desirable benefit of driving the honing stones 145 radially without having to stop or slow the rotation of the drive axle 120. With appropriate process control as described further below, a boring or honing process can be continuous until a predetermined dimension is reached and/or the effective pressure exerted by the cutting or abrading tool (or feed rate) can be adjusted to optimize the removal of material.
In one embodiment, the magnetic coupling 110 comprises at least one first set of spaced apart magnets 1610 connected to the inner periphery of the magnetic coupling 110. The magnets 1610 have their opposing north and south poles pointing radially, while immediately adjacent magnets alternate in polarity.
Likewise there is at least one second set of spaced apart magnets 1630 connected to the outer periphery of the inner axle 130. The magnets have their opposing north and south poles pointing radially, while immediately adjacent magnets alternate in polarity.
The inner magnets 1630 connected to the inner axle 130 are separated from the outer magnets 1610 connected to the inner circumference of the magnetic coupling 110 by a gap 103. The annular drive axle 120 passes through gap 103 and surrounds the inner axle 130 and attached magnets 1630. As at least this portion of the drive axle 120 within the magnetic field of the magnetic coupling is non-magnetic, the magnets stay aligned so that the magnetic coupling 110 and inner axle 130 stay aligned and are co-rotated independently of the drive axle. Magnetic coupling 110 can deploy opposing magnets arrays 1610 and 1630 or magnets 1630 and an AC induction coil replacing magnets 1610.
In a more preferred embodiment, the inner axle 130 has a polygonal cross-section to provide flat faxes for attaching a plurality of high strength magnets of opposing polarity, as indicated by the N and S poles in
It should be appreciated that as illustrated generally in
A plurality of rotary bearings 160 separate the rotating magnetic coupling 110, inner drive axial 120 and inner axle 130 that is connected to the pinion gear 135. The rotary bearings 160 are provided as pairs disposed at opposing sides of the magnetic coupling 110 distal and proximal to the honing head 140.
As illustrated in
It is also preferred that either the drive shaft 120 or a portion thereof within the magnetic field of coupling 110, (drive shaft portion 120′ as illustrated in
The inner axial 130 is connected to the pinion gear 145 that drives the abrasive members 145. When the inner and outer axial are driven to rotate at the same speed the pinion gear will not engage the gear mechanism that drives the honing/abrasive stones radially. However, when there is a difference in drive speed, the magnetic coupling 110 prevents slippage of the inner axial 130 by magnetic attraction, the differential speed will be converted into a torque that turns the pinion gear 135 urge the linear gear mechanism 137 coupled to the honing stones 145 forward or backward, depending on the which axle is being driven at a slower speed.
Hence, another aspect of the invention is at least one drive means for rotating the outer magnetic coupling 110 that transfers torque from the inner axle 130 to the radial positioning means for the honing stones 145.
Drive means, such as for motor 510 to the magnetic coupling 110 can be direct, or via gears or an offset drive belt, as for example via an axial gap motor 505 in which the magnetic coupling 110 is essentially the hollow core central shaft to accommodate the drive shaft 120.
One or more sensors 512 are optionally in communication with drive axle 120, such as a rotary encoders or a means detect the motor current draw of motor 520 to determine the position and/or point of contact of the honing stones. Alternatively, in-line or equivalent torque sensor 513 can be deployed on a portion of axle 120, such as a torque strain gauge to measure the load on the honing stones.
In a more preferred embodiment, Illustrated in
The above controls can be used in at least 2 modes of operation. First, based on first establishing a zero reference for the hone stone or cutting tool position, the controller can track the position of the hones with the software in the PLC 710 or controller 700 deployed to adjust hone position based on average material wear rates. Alternatively, deploying a strain gauge along with or as sensor 512, the load on the main drive 120 is detected to determine when the honing stones contact the work piece 10. As work pieces vary in exact dimensions before honing, it is useful to be able to detect when the hone stones contact the surface of the work piece. This can be accomplished with the torque strain gauge 513, or alternatively the load on the primary servo motor drive 520.
The inventive magnetic coupling 110 can be deployed to achieve the benefit of a faster machining process, in that the rotary material removal does not need to stop for the adjustment of the stone position. The magnetic coupling process is expected to provide better process control due to continuous feedback of motor torque or other sensor output indicating wear rate, and hence greater process reliability as well as final product quality. For examples, as metals that may be deployed in different work pieces have variable properties, the application of a constant pressure of the hone stone against the work piece is frequently insufficient to obtain an intended surface finish in a single process. However, monitoring the loading of the primary drive enables the application of variable pressure of the honing stones against the work piece, according to a predetermined program, to routinely obtain a targeted metal surface finish directly from the honing process.
While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be within the spirit and scope of the invention as defined by the appended claims.
The present application claims the benefit of priority to the US Provisional Patent Application of the same title having application Ser. No. 61/859,414 which was filed on Jul. 29, 2013, and is incorporated herein by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5125299 | Strait | Jun 1992 | A |
| 20080233851 | Kubo | Sep 2008 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 61859414 | Jul 2013 | US |
