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EP-4735196-A1 - A REAMER AND A REAMER AND FLOATING HEAD ASSEMBLY

EP4735196A1EP 4735196 A1EP4735196 A1EP 4735196A1EP-4735196-A1

Abstract

The invention relates to a reamer and to a reamer and floating head assembly. The task of the invention is to provide a reamer that will provide for high machining accuracy, will be adjustable for machining workpieces having different diameters and will allow for quick restoration or replacement of blades and guides. A reamer (1; 101) comprises a head (2; 102), at least three guides (3; 103), each consisting of a guide part (3 a; 103 a), movably arranged in the head, and a pointed part (3b; 103b), the guides being arranged at an angle φ with respect to the central axis of the head, and wherein part of the surface of the pointed part of the respective guide, which is intended to come in contact with the workpiece, is arranged at the same angle φ with respect to the central axis of the respective guide so that part of the surface of the pointed part of the respective guide, which is intended to come in contact with the workpiece, is arranged parallel to the central axis of the head, a blade holder (4; 104), an adjusting screw (5; 105) of the guides, elements (3c, 5a, 5b, 11, 12; 103c, 111) for transferring the translational movement of the adjusting screw (5; 105) of the guides to the guides and the blade holder, and a blade (6; 106) for machining the workpiece.

Inventors

  • Groselj, Tomaz

Assignees

  • Groselj, Tomaz

Dates

Publication Date
20260506
Application Date
20240624

Claims (16)

  1. 1. A reamer (1; 101) that comprises: - a head (2; 102), - at least three guides (3; 103), preferably four guides, each of the guides consisting of a guide part (3a; 103a), movably arranged in the head and a pointed part (3b; 103b) that connects to the guide part in its longitudinal axis by protruding from the head, the guides being arranged concentrically around the central axis of the head, the guides being fixable in the head by means of fastening means (10; 110) of the guides, the guides in the head being arranged at an angle cp with respect to the central axis of the head, and wherein part of the surface of the pointed part of the respective guide, which is intended to come in contact with the workpiece, is arranged at the same angle cp with respect to the central axis of the respective guide so that part of the surface of the pointed part of the respective guide, which is intended to come in contact with the workpiece, is arranged parallel to the central axis of the head, - a blade holder (4; 104) that is arranged in the head so as to be movable in the longitudinal direction of the head and fixable in the head by means of at least one fastening screw (9; 109) of the blade holder, - an adjusting screw (5; 105) of the guides, which engages the head via a thread and is arranged in such a way to be movable in the longitudinal direction of the head during its rotation, - elements (3c, 5a, 5b, 11, 12; 103c, 111) for transferring the translational movement of the adjusting screw (5; 105) of the guides to the guides and the blade holder, and - a blade (6; 106) for machining the workpiece, which is arranged to be movable in the radial direction relative to the head by means of the blade position adjusting screw (7; 107) and which is fixable by means of the blade fastening screw (8; 108).
  2. 2. Reamer according to claim 1, characterized in that the head (2, 102) is cylindrical.
  3. 3. Reamer according to claim 1 or 2, characterized in that the adjusting screw (5; 105) of the guides is formed as a threaded pin with a hexagonal hole that engages a threaded hole in the head (2; 102), which is formed in the axial direction of the head.
  4. 4. Reamer according to any of the preceding claims, characterized in that the angle (p is selected in the range from 1° to 5°, preferably 3° to 4°, most preferably about 3.8°.
  5. 5. Reamer according to any of the preceding claims, characterized in that the pointed part (3b; 103b) of the guides is provided with a chamfer (3e; 103e) at the end which faces the workpiece during machining.
  6. 6. Reamer according to any of the preceding claims for turning the outer diameter of a workpiece, characterized in that the fastening means of the guides, with which it is possible to fix the position of the guides (3) in the head, are formed by fastening screws (10) of the guides, which are arranged in the threaded holes in the head so that they exert pressure on the guide part (3a) of the guides in the fixed state.
  7. 7. Reamer according to any of the preceding claims for turning the outer diameter of a workpiece, characterized by having elements for transferring the translational movement of the adjusting screw to the guides and the blade holder, which are formed by a groove (3c) of the guides, which engages a tongue (5a) of the adjusting screw to transfer the translational movement of the adjusting screw to the guides and by a groove (5b) of the adjusting screw, which engages the pin (11) to transfer the translational movement of the adjusting screw (5) to the blade holder (4) indirectly via the lock element (12) of the blade holder position.
  8. 8. Reamer according to any of the preceding claims for turning the outer diameter of a workpiece, characterized in that the blade holder (4) and the lock element (12) of the blade holder position are formed in the form of a dovetail, wherein the blade holder (4) and the lock element (12) of the blade holder position are arranged in a matching dovetail cutout in the head (2), with the bottom (2a) of the dovetail cutout in the head (2) and the adjacent surface (4a, 12a) of the blade holder (4) and the lock element (12) of the blade holder position being preferably formed as profiled surfaces.
  9. 9. Reamer according to any of the preceding claims for turning the outer diameter of a workpiece, characterized in that the bottom (2a) of the dovetail cutout in the head (2) is inclined in the longitudinal direction of the head at the same angle cp with respect to the central axis of the head as the guides.
  10. 10. Reamer according to any of the preceding claims for turning the outer diameter of a workpiece, characterized in that the cross-sectional shape of the respective guide (3) is selected from the group consisting of a circle (3') and a polygon, such as equilateral triangle, square (3"), hexagon (3"'), octagon, etc., wherein the sides of the polygon are preferably provided with circular recesses (3 "a; 3 '"a) in the longitudinal direction of the guide, the radius of a respective circular recess being selected in a way that it is larger than or equal to the largest radius of the workpiece to be machined.
  11. 11. Reamer according to any one of claims 1 to 5 for turning the inner diameter of a workpiece, characterized in that the fastening means of the guides, with which it is possible to fix the position of the guides (103) in the head, are formed by the fastening screw (110) of the guides, which is arranged in the threaded hole in the axial direction of the head in such a way that, in the fixed state, it exerts pressure on the surface (103d) of the guides, which faces away from the workpiece during machining.
  12. 12. Reamer according to claim 11 or any of claims 1 to 5 for turning the inner diameter of a workpiece, characterized in that the elements for transferring the translational movement of the adjusting screw to the guides and the blade holder are formed by the groove (103c) of the guides, which engages the adjusting screw (105) to transfer the translational movement of the adjusting screw to the guides and the adjusting screw (111) of the axial position to transfer the translational movement of the adjusting screw (105) to the blade holder (104).
  13. 13. Reamer according to claim 11, 12 or any of claims 1 to 5 for turning the inner diameter of a workpiece, characterized in that the cross-sectional shape of a respective guide is selected from the group consisting of a circle and a polygon, such as equilateral triangle, square, hexagon, octagon, etc., the sides of the polygon being preferably provided with circular protrusions in the longitudinal direction of the guide, the radius of each circular protrusion being selected in a way that it is smaller than or equal to the smallest radius of the workpiece to be machined.
  14. 14. Reamer according to any one of claims 11 to 13 or 1 to 5 for turning the inner diameter of a workpiece, characterized in that the blade holder (104) comprises the guide part (104a) of the holder and the blade holding part (104b), which are inseparably connected to each other, e.g. by brazing, wherein the blade holder (104) is preferably located in the central axis of the head.
  15. 15. A reamer and floating head (300) assembly according to any of the preceding claims, comprising: - a first set (310) of parts, which further comprises at least a flanged annular part (311) with an internal thread for connection to the reamer; - a second set (320) of parts, which further comprises at least a clamping shaft (321) for connection to the machining tool and a shaft (322), which is received by the flanged annular part (311) and - springs (330) which interconnect the first (310) and the second (320) sets of parts so that the first set of parts is movable in the radial direction with respect to the second set of parts, the reamer being provided on its periphery with an external thread for connection with the internal thread of the flanged annular part (311) of the floating head.
  16. 16. Assembly according to claim 15, characterized in that the first set (310) of parts of the floating head parts further comprises: - a slide bush (312) placed inside the flanged annular part (311), - a cover plate (313) closing the slide bush (312) in the flanged annular part (311) - a snap ring (314) for fixing the cover plate (313), and in that the second set (320) of parts of the floating head further comprises: - a diameter adapter (323), - a nut (324) connecting the diameter adapter (323) to the clamping shaft (321), - a spring casing (325) connected to the diameter adapter (323), - sliding pins (326) that are pre-tensioned by springs (330) and rest against the slide bush (312), - a radial cage (327) that prevents the springs (330) and sliding pins (326) from falling out of the spring casing (325), - a cage (328) with bearing balls that prevent the movement of the first set (310) of parts in the axial direction.

Description

A reamer and a reamer and floating head assembly Field of invention The invention relates to a reamer for precision machining by turning the outer or inner diameter of a workpiece and to a reamer and floating head assembly. Prior Art In conventional turning, a workpiece is clamped in the chuck of a machine tool in such a way that the surface to be machined is accessible from another direction. A processing blade is guided from this direction depending on the necessary machining operations. However, this type of machining is not sufficient when high machining accuracy is required. To produce dimensions in more precise tolerance ranges, the workpiece can be subsequently ground after rough machining or processed with dedicated tools for precision machining, which are particularly suitable for large-scale production. Some of the reasons why conventional turning cannot achieve sufficient precision are vibrations, deviation due to deviations of the machine itself, bending of the workpiece, as the cutting force acts on only one side, etc. Dedicated reamers are most commonly used for the batch production of precison-tumed pieces with defined accuracy in micrometres. A single tip reamer is known from prior art, which is disclosed in DE 40 07 175 Al. The reamer has a cutter head with a cutting pad and two guide rails made of plastics and intended for fine machining of bores. The tool provides precise surface machining, but its weakness is that it is essentially a dedicated tool for machining a workpiece of a certain diameter. When the user wants to machine a workpiece of a different diameter, a new tool must be ordered, which entails high costs. Document GB 1366761 A discloses an adjustable tool for precision machining, with which it is possible to machine workpieces in a certain range of different diameters. The adjustable reamer comprises an elongated cylindrical holder having an axial slot and a pair of juxtaposed blades radially slidable in the slot in a radial direction. The axially movable cam engages said blades to move them simultaneously radially outwards or inwards. The advantage of said reamer is that it enables workpieces of different diameters to be machined due to the adjustability of the blades. Since the two blades are placed diametrically opposite each other, the bending cutting forces cancel each other out, which increases the machining accuracy. A disadvantage of the reamer lies in the fact that the two blades are placed only in one plane, which does not provide sufficient support to the workpiece, which is necessary to compensate for errors due to imperfect alignment of the machining tool and the workpiece. Document JP 2003165021 A discloses an adjustable reamer with dedicated machining blades that also serve as support guides for the workpiece. The machining diameter is adjusted by turning the nut which moves the cone inside the tool which pushes the machining blades to the desired machining diameter. The main problem with such a tool is that it does not provide for precise machining along the entire depth of the bore, as the machining blade or guide starts rather behind the front tip of the tool. The tip of the tool, however, limits the depth to which the tool can be pushed into the bore. Oscillating heads (sometimes called floating heads) are also known from prior art, which are installed between a reamer and a machine. Springs are built into the oscillating head, which enable radial movements of the reamer relative to the workpiece axis. In this way, the reamer constantly adjusts to the position of the workpiece during machining, which reduces machining errors due to axial misalignment of the workpiece axis and the clamping axis, as well as due to vibrations. The oscillating head therefore flexibly connects the reamer to the machining tool. The lower the weight of the moving part of the oscillating head, the higher the machining accuracy. Technical problem The technical problem is how to provide a reamer that will provide for high machining accuracy, will be adjustable for machining workpieces having different diameters and will allow for quick restoration or replacement of blades and guides. A further task of the invention is to provide a reamer for machining the inner diameter of a workpiece, which will enable machining along the entire length of the hole. A further task of the invention is to provide a floating head having a low weight of the moving part of the floating head that will allow higher machining accuracy. Solution to the technical problem The technical problem is solved by a reamer that comprises: - a head, - at least three guides, preferably four guides, each of the guides consisting of a guide part movably arranged in the head and a pointed part that connects to the guide part in its longitudinal axis by protruding from the head, the guides being arranged concentrically around the central axis of the head, the guides being fixable in the head by means of fastening means of