This disclosure relates to a tool holder that includes features for directing coolant flow onto a tool workpiece interface. More specifically, this disclosure relates to a tool holder that includes openings that directs coolant flow to maintain a desired fluid flow rate at the tool workpiece interface regardless of tool rotational speed.
Conventional machining process may utilize a stream of coolant directed onto the cutting tool to maintain a constant temperature. Without coolant flow, friction from the tool and the workpiece generate heat of a degree sufficient to decrease tool life. Further, machining produces metal chips that are preferably evacuated from the machining area in order to prevent damage to the tool and work piece. The stream of coolant aids evacuation of metal chips from the work piece during machining.
Typical arrangements for directing coolant onto a tool include the use of a plurality of hoses arranged to direct fluid onto the tool. These hoses are typically of a semi-rigid design extending around a tool and manually positioned to direct coolant onto a tool. Often during the machining, the work piece or chips bump and contact the coolant lines changing the position of the hose such that the coolant is no longer directed as originally positioned onto the tool. In addition, hoses are often not positionable for providing coolant as desired when machining of relatively deep openings or holes. Further, in some part configurations an adjustable coolant hose is simply not feasible and does not supply and direct coolant flow adequately to the tool.
Known tool holders flow coolant into a tool and workpiece interface. Disadvantageously, the forces rotating the tool spray the cooling fluid outwardly away from the tool workpiece interface. Accordingly, merely spraying fluid out of a tool does not provide the desired benefits. Instead, much of the cooling fluid is wasted as being sprayed outside of the tool workpiece interface. In some instances an increased pump pressure is utilized in an effort to overcome these deficiencies. However, such efforts cannot overcome the inefficiencies inherent in prior art designs.
An example tool holder secures a tool and includes an insert that defines passages for directing coolant onto a tool during machining operations.
An example tool holder includes an insert within an annular channel in fluid communication with an inlet defined by the insert pressed into the face of the tool holder. The insert mounts within a body that provides for rigidly mounting the tool to the machine. Coolant flows through the inlet and internal channels to exit the insert through passages directing coolant fluid along the axis of the tool.
Accordingly, the example tool holder provides easy mounting to existing machinery while directing coolant along the entire length of a tool without complex piping and valving and does not interfere with the work piece tool interface during machining.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiments. The drawings that accompany the detailed description can be briefly described as follows.
Referring to the
Conventional tools that include flow through coolant features are inefficient and provide little benefit. This is so because rotation of the tool holder generates centrifugal forces that act on the coolant flow leaving openings. The centrifugal forces drive the coolant outward and away from the tool workpiece interface. The example disclosed features provides for coolant to be directed as is required to counteract the centrifugal forces and provide coolant at the tool workpiece interface.
The example tool holder 10 includes the mounting flange 46 including a groove 48. From the mounting flange 46 back toward the inlet 14 is a tapered portion 50 that is tapered at a desired angle 52. The desired angle is a feature specified to allow mounting of the tool holder 10 is specifically configured machines. Moreover, the specific configuration of the flange 46 further provides the required dimensions to provide for mounting in a desired machine tool.
The example tool holder 10 includes a cavity 28 that receives the tool 30. The example cavity 28 provides a thermal fit mounting of the tool 30. Heating the upper portion of the tool holder 10 expands the cavity 28 allowing insertion of the tool 30. Subsequent cooling causes the cavity body 12 to contract around the tool 30 for a secure fit. Moreover, although thermal fit mounting is disclosed, other mounting configurations such as using fasteners to secure the tool within the bore are also within the contemplation and scope of this disclosure.
The cavity 28 is in communication with the fluid inlet 14 on a rear end of the tool holder 10 through cavities 53, 54, 55, and 56. The cavities 53, 54, 55, and 56 are all in fluid communication with each other and the inlet 14, and lateral passages 16.
Referring to
Referring to
The cavity 28 includes an inner diameter 64 that is determined to fit a specific tool diameter. As appreciated, the size of the inner diameter 64 is as known to provide the desired thermal fit with the tool 30. The inner diameter 64 therefore may vary as is known to accommodate tool sizes of standard and custom sizes.
The conical wall 40 is spaced a radial distance 66 from the inner diameter 64. Accordingly, the smallest diameter at the tip of the conical wall 40 as is indicated at 62 is spaced apart from any tool mounted within the cavity 28. The distance from the cavity 28 and thereby the tool 30 provides for a desired alignment of coolant flow on the surface of the tool 30. Moreover, the diameter 62 will vary with the diameter 64. The first wall 38 is disposed at a diameter 60 that is larger than the diameter 62 to define the annular channel 24. As appreciated, the difference in the diameter 60 and 62 define the radial width of the annular channel 24, and thereby the insert 24 that is mounted therein. The overall diameter 58 of the tool holder is spaced radially further outward and represents the largest diameter of the tool holder 10. Because the insert 24 is fixed by a welding or brazing process within the annular channel 24, no other external securing means is required. This provides for a low profile and low interference face 26 of the example tool holder 10. The smaller profile provides for use of the tool holder 26 in applications not feasible for tool holders with larger structures mounted to the forward most face 26.
The example annular channel 22 is generated at a depth 65. The depth 65 is determined based on a desired length of the passage 32 to the ports 34. The length and size of each of the passages 32 is determined to provide a desired angle and velocity of coolant to counter the centrifugal forces generated during rotation of the tool holder 10.
Referring to
The example ports 34 (grooves) include an angled inner surface 72. The angled inner surface 72 is disposed at an angle 74 that matches the angle 84 (
The example insert 24 includes a groove 75 for a brazing wire material. During assembly of the tool holder 10, brazing material in the form of a wire is received within the groove 75. The inset 24 is then placed within the annular cavity 22 with a light press fit and brazed in place. The brazing of the insert within the annular cavity 22 provides a substantially permanent fit. As appreciated, other welding techniques may also be utilized within the scope and contemplation of this disclosure.
Referring to
L>0.75 (W/tan A),
The ports 34 are spaced a distance 86 away from the tool 30 to apply coolant to the cutting surfaces of the tool. The distance 86 is the distance beginning at the outer circumference of the cavity 28 and ending at the radially innermost edge of the port 34. The port 34 location relative to the tool 30 provides for the creation of coolant velocity and inertia that overcome centrifugal forces. In this example the distance 86 is between 0.03 and 0.25 inches away from the outer surface of the cavity 28 and thereby the tool 30.
The parallel walls that define the passage 32 stabilize coolant flow. Moreover, the passage 32 stabilizes and directs coolant flow by overcoming and directing the inertia within the coolant flow caused by flowing through other coolant passages of the tool holder 10. As appreciated, inertia forces of coolant flow influence the character of flow emitted from the ports 34. In the disclosed example, such inertial effects are neutralized by the defined location and size of the passage 32. In other words, turbulence and inertia produced in the coolant as it flows through the lateral passages 16 and into through the annular channel 22 are neutralized by defining a unidirectional, parallel walled passage 32 prior to exiting through the ports 34.
Moreover, maximizing the velocity of the coolant flow exiting the ports 34 increases the energy available to counteract centrifugal forces encountered during operation. This is accomplished by limiting loses due to turbulent flows. The passage 32 substantially eliminates such turbulence by creating laminar flow for the first length prior to exiting the ports 34. Further, the velocity of the coolant is maintained while coverage is optimized by the example shaped rectangular ports. The elongated partial conical wall 40 and angle of the passage 32 disperses coolant about the circumference of the tool while limiting volume, thereby maintaining the velocity of the coolant flow.
Accordingly, the example tool holder provides for the increased coolant velocity and direction to overcome forces encountered during operation to efficiently direct coolant at the tool workpiece interface.
The foregoing description is exemplary and not just a material specification. The invention has been described in an illustrative manner, and should be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications are within the scope of this invention. It is understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.
This application is a continuation-in-part of U.S. patent application Ser. No. 11/636,012 filed Dec. 7, 2006 which is continuation-in-part of co-pending U.S. application Ser. No. 11/098,979 filed on Apr. 5, 2005 which is a continuation-in-part of U.S. application Ser. No. 10/197,390 filed on Jul. 17, 2002, now U.S. Pat. No. 7,134,812, issued on Nov. 14, 2006.
Number | Date | Country | |
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Parent | 11636012 | Dec 2006 | US |
Child | 12791168 | US | |
Parent | 11098979 | Apr 2005 | US |
Child | 11636012 | US | |
Parent | 10197390 | Jul 2002 | US |
Child | 11098979 | US |