FR3111576A3 - CUTTING TOOL ASSISTED BY ULTRASONIC VIBRATION FOR LATHE - Google Patents

Abstract

Cutting tool assisted by ultrasonic vibration for a lathe, consisting of a casing (1), a piezoelectric ceramic transducer (2) housed in the casing (1) and a sonotrode (3), symmetrical and aligned on an axis (E), as well as a cutting tip (5), in which: the casing (1) has the shape of a vase with a closed proximal end, a peripheral wall arranged around the piezoelectric ceramic transducer (2) , an open distal end and a handle (7) extending from one side of the peripheral wall and adapted to be gripped by a tower turret jaw; the sonotrode (3) is attached to the open distal end of the housing (1) by a connection plate (4) and has a proximal end in contact with the piezoelectric ceramic transducer (2); and the cutting tip (5) is supported on a distal end of the sonotrode (3); characterized in that: the clamp (7) is an elongated boss which extends from the peripheral wall of the casing (1) and along at least a part thereof in a direction parallel to the central axis ( E), and which comprises two opposed surfaces parallel to each other (7a, 7b) and parallel to the central axis (E), dimensioned to be held between two horizontal claws of the jaw of the turret of the lathe; and the piezoelectric ceramic transducer (2) provides ultrasonic vibration in a direction aligned with the central axis (E) and the cutting tip (5) has a depth advancing direction parallel to the direction of vibration.

Description

CUTTING TOOL ASSISTED BY ULTRASONIC VIBRATION FOR LATHEField of technology

The present invention relates generally to an ultrasonic vibration assisted cutting tool for use in lathe machining, and more particularly to a cutting tool that includes an ultrasonically vibrated cutting tip and a housing adapted to be held in a jaw standard lathe turret so that through the turret the cutting tip can be applied against a rotating metal workpiece on the lathe to machine it.

State of the art

The technique of lathe machining is known, consisting in pressing the tip of a cutting tool against the surface of a metal workpiece which rotates on a lathe while the tool advances longitudinally along a passage , in order to detach the chips from the surface of the metal workpiece, and to perform a deep advance of the tool before each new pass to ensure detachment of the chips to the desired depth.

Also known is the method of applying ultrasonic vibrations to the tip of the cutting tool during the machining operation, while the tool advances longitudinally, to facilitate the detachment of chips associated with the cut of the metal work piece.

US 3559259 A relates to an ultrasonic vibration assisted cutting tool, specific to lathe machining, which comprises a housing, a piezoelectric ceramic transducer, a sonotrode, and a cutting tip. The housing, the piezoelectric ceramic transducer and the sonotrode are axisymmetric and aligned on a central axis. The piezoelectric ceramic transducer is housed inside the housing, and the housing is shaped like a vase with a closed proximal end, a peripheral wall disposed around the piezoelectric ceramic transducer, and an open distal end. The sonotrode is attached to the open distal end of the housing by a connection plate and has a proximal end that contacts the piezoelectric ceramic transducer. The cutting tip is supported on a distal end of the sonotrode. The housing further includes a handle extending from one side of the peripheral wall and designed to be gripped by a standard tower turret jaw with two horizontal claws.

However, on the cutting tool described in said US 3559259 A, the handle is in the form of a rod of square cross section which extends from the peripheral wall of the housing in a direction perpendicular to the central axis of the tool, so that when the handle is held between the two horizontal claws of the lathe turret jaw, the central axis of the tool is in a vertical position. Furthermore, the cutting tip is arranged on the distal end of the sonotrode in a position such that its direction of advance in depth is also perpendicular to the central axis of the tool so that when machining d metal workpiece on the lathe, and due to the different force components generated, the tool elements are subjected to considerable bending and torsion stresses affecting the precision and efficiency of the machining .

The present invention relates to a cutting tool assisted by ultrasonic vibration, suitable for lathe machining, and whose rigidity and resistance to bending are high.

An ultrasonic vibration assisted lathe cutting tool includes a housing, a piezoelectric ceramic transducer housed in the housing, a sonotrode, and a cutting tip. The housing, the piezoelectric ceramic transducer and the sonotrode are axisymmetric and aligned on a central axis. The housing has the shape of a vase with a closed proximal end, a peripheral wall arranged around the piezoelectric ceramic transducer, and an open distal end. The sonotrode is attached to the open distal end of the housing by a connection plate and has a proximal end in contact with the piezoelectric ceramic transducer. The cutting tip is supported on a distal end of the sonotrode.

The housing has a handle formed by an elongated boss that extends from the peripheral wall of the housing and over at least a portion thereof in a direction parallel to the central axis. The boss constituting the handle has two opposed surfaces parallel to each other which are themselves parallel to the central axis. The two opposing surfaces parallel to each other are sized to be held between two horizontal claws of a tower turret jaw.

The piezoelectric ceramic transducer is designed and arranged to provide reciprocating ultrasonic vibration in the sonotrode in the direction of the central axis, and the cutting tip has a direction of depth advancement parallel to the direction of the reciprocating ultrasonic vibration.

The handle located on one side of the housing and along it allows for an extremely compact design which, combined with the direction of depth advancement of the cutting tip aligned with the central axis, provides the cutting tool high rigidity and high resistance to bending which result in high precision and efficiency in lathe machining operations.

The handle has a substantially rectangular cross-section and can be defined through three dimensions: a handle thickness, measured by the distance between the two opposed surfaces parallel to each other; a handle width, measured in a direction parallel to the two opposing surfaces parallel to each other and perpendicular to the central axis; and a handle length, measured in a direction parallel to the central axis. According to one embodiment, the handle width is 1 to 1.5 times the handle thickness, and the handle length is at least 3 times the handle thickness.

Similarly, the housing has a housing length, measured from the proximal end to the distal end in a direction parallel to the central axis. According to a preferred embodiment, the handle length is 50% to 100% of the housing length. Furthermore, preferably, the two opposite surfaces parallel to each other of the handle are equidistant from a geometric plane containing the central axis.

For example, the handle thickness is 12 to 22 millimeters, allowing the cutter handle to be held by a standard lathe turret jaw with two horizontal claws, with the two opposing surfaces parallel between them of the handle held by the two horizontal claws of the standard jaw, keeping the central axis of the tool in a horizontal position.

The ultrasonic vibration assisted cutting tool further includes a cable connector installed in the housing and connected to the piezoelectric ceramic transducer. Thus, a flexible external connection cable connected to the cable connector makes it possible to connect the piezoelectric ceramic transducer to an external vibration generator. The external vibration generator outputs a high frequency, high voltage alternating current signal which drives the piezoelectric ceramic transducer into alternate expansions (when voltage is positive) and contractions (when voltage is negative) which produce the vibration reciprocating ultrasonic wave in the sonotrode.

On the cutting tool of the present invention, the piezoelectric ceramic transducer is preferably designed to produce, when excited by the external vibration generator, a 40 kHz ultrasonic vibration in the sonotrode which is transmitted to the workpiece. metal work by the cutting tip.

These characteristics and advantages as well as others will be better understood using a detailed description of an embodiment of the invention given by way of example, which refers to the accompanying drawings, in which :

shows a perspective view of an ultrasonic vibration assisted lathe cutting tool according to one embodiment of the present invention;

shows a front view of the cutting tool of the ; and

represents a cross-sectional view taken from the plane III-III of the .

Detailed description of an exemplary embodiment

Referring to the Figures, the ultrasonic vibration-assisted cutting tool for lathe of the present invention comprises, according to the illustrated embodiment, a housing 1, a piezoelectric ceramic transducer 2 housed in the housing 1, a sonotrode 3, and a working tip 5 supported on a distal end 3b of sonotrode 3. Housing 1, piezoelectric ceramic transducer 2 and sonotrode 3 are axisymmetric and aligned on a central axis E (see ).

The housing 1 has the shape of a vase and has a closed proximal end 1a, a peripheral wall arranged around the piezoelectric ceramic transducer 2, and an open distal end 1b. The sonotrode 3 is fixed to the open distal end 1b of the casing 1 by a connection plate 4 connected to the sonotrode 3. A retaining ring 10, fixed by threading on the distal end 1b of the casing 1, holds the connection plate connection 4 in position and the proximal end 3a of the sonotrode 3 in contact with the piezoelectric ceramic transducer 2. The connection plate 4 comprises annular grooves 11 which facilitate the reciprocating vibration of the sonotrode 3. The tip working 5 is fixed on the distal end 3b of the sonotrode 3 using a screw 12. In this embodiment example the connection plate 4 is formed at this proximal end 3a of the sonotrode 3.

Said annular grooves 11 of the connection plate 4 are formed on opposite sides of the connection plate 4. The annular grooves 11 are of different diameters and are concentric with the central axis E. These thinnings provide a certain elasticity to the plate connection 12.

The tool also includes a handle 7 formed by an elongated boss which extends from the peripheral wall of the housing 1 and along at least a part thereof in a direction parallel to the central axis E. The boss which constitutes the handle comprises two opposite surfaces parallel to each other 7a, 7b, themselves parallel to the central axis E. These two opposite surfaces parallel to each other 7a, 7b are equidistant from a geometric plane containing the central axis E and are sized to be held between two horizontal claws of a standard tower turret jaw.

The piezoelectric ceramic transducer 2 provides reciprocating ultrasonic vibration in a direction parallel to the center axis E, and the cutting tip 5 has a direction of depth advancement parallel to the direction of ultrasonic vibration.

The handle 7 has a handle thickness D1, measured by the distance between the two opposite surfaces parallel to each other 7a, 7b; a handle width D2, measured in a direction parallel to the two opposite surfaces parallel to each other 7a, 7b and perpendicular to the central axis E; and a handle length D3, measured in a direction parallel to the central axis E. The handle width D2 is 1 to 1.5 times the handle thickness D1, and the handle length D3 is 3 times or plus handle thickness D1.

The handle thickness D1 is 12 to 22 millimeters. Thus, the two opposite surfaces parallel to each other 7a, 7b can be caught between the two horizontal claws of a standard lathe turret jaw while maintaining the central axis E of the cutting tool in a horizontal position.

The housing 1 has a housing length D4, measured in a direction parallel to the central axis E, and the handle length D3 is 50% to 100% of the housing length D4. In the illustrated embodiment (see ) the handle length D3 is equal to the housing length D4.

The ultrasonic vibration assisted cutting tool further comprises a cable connector 6 installed in the housing 1 and connected to the piezoelectric ceramic transducer 2. Thus, the piezoelectric ceramic transducer 2 can be connected to an external vibration generator 8 by a cable hose 9 connected to cable connector 6. The piezoelectric ceramic transducer 2 is designed to produce a 40 kHz ultrasonic vibration when excited by the external vibration generator 8.

The scope of the present invention is defined in the appended claims.

Claims (8)

Ultrasonic vibration assisted cutting tool for a lathe, comprising a casing (1), a piezoelectric ceramic transducer (2) housed in the casing (1), and a sonotrode (3), which are axisymmetric and aligned on a central axis (E ), as well as a cutting tip (5), in which:
the housing (1) has the shape of a vase with a closed proximal end, a peripheral wall arranged around the piezoelectric ceramic transducer (2), an open distal end, and a handle (7) which extends from one side of the peripheral wall and which is designed to be gripped by a tower turret jaw;
the sonotrode (3) is fixed to the open distal end of the casing (1) by a connection plate (4) and has a proximal end in contact with the piezoelectric ceramic transducer (2); and
the cutting tip (5) is supported on a distal end of the sonotrode (3);
characterized in that:
the handle (7) is an elongated boss which extends from the peripheral wall of the casing (1) and along at least a part thereof in a direction parallel to the central axis (E), and which has two opposed surfaces parallel to each other (7a, 7b) and parallel to the central axis (E), dimensioned to be held between two horizontal claws of the tower turret jaw; and
the piezoelectric ceramic transducer (2) provides ultrasonic vibration in a direction aligned with the central axis (E) and the cutting tip (5) has a depth advancing direction parallel to the direction of ultrasonic vibration. Ultrasonic vibration-assisted cutting tool according to claim 1, wherein the handle (7) has a handle thickness (D1), measured by the distance between the two opposing surfaces parallel to each other (7a, 7b); a handle width (D2), measured in a direction parallel to the two opposing surfaces parallel to each other (7a, 7b) and perpendicular to the central axis (E); and a handle length (D3), measured in a direction parallel to the central axis (E), and in which the handle width (D2) is 1 to 1.5 times the handle thickness (D3), and the handle length (D3) is at least 3 times the handle thickness (D1). Ultrasonic vibration assisted cutting tool according to claim 2, wherein the housing (5) has a housing length (D4), measured in a direction parallel to the central axis (E), and the handle length (D3) is 50% to 100% of the case length (D4). Ultrasonic vibration assisted cutting tool according to claim 2 or 3, wherein the handle thickness (D1) is 12 to 22 millimetres. Ultrasonic vibration assisted cutting tool according to claim 1, further comprising a cable connector (6) installed in the housing (1) and connected to the piezoelectric ceramic transducer (2), wherein by the cable connector (6) the piezoelectric ceramic transducer (2) can be connected to an external vibration generator (8) by means of a flexible cable (9). Ultrasonic vibration assisted cutting tool according to claim 5, wherein the piezoelectric ceramic transducer (2) is arranged to produce a 40 kHz ultrasonic vibration in the sonotrode when excited by the external vibration generator (8). Cutting tool assisted by ultrasonic vibration according to claim 1, wherein the connection plate (4) has annular grooves (11) which determine thinnings and are concentric with the axis E, said annular grooves (11) being formed on opposite sides of the connection plate (4). Ultrasonic vibration assisted cutting tool according to claim 7, wherein the connection plate (4) is formed at a proximal end (3a) of the sonotrode (3).