Non-rotating boring tools for internal turning and boring arrangements including such boring tools.

Abstract

A non-rotating boring tool for internal turning includes: - a boring bar (2) including an extended body (6); - a cutting element (5) having a rake face (30), a flank face (32), and a cutting edge (33); and - an electrically controlled vibration actuator (8) for active vibration damping of the boring bar. When viewed in a cross-section perpendicular to the longitudinal axis (7) of the extended body and intersecting the cutting edge at the radially outermost point (39), straight and imaginary first reference line L1 and second reference line L2 intersect the cutting edge at the radially outermost point, wherein: · the first reference line L1 extends at an angle of 6° relative to the flank face (32) on the outside of the cutting element, and · the second reference line L2 extends between the rake face (30) and the flank face (32) at an angle of 10° to 40° relative to the first reference line L1. The actuator is arranged such that its working axis (10) extends parallel to the second reference line L2.

Description

[0001] Technical Field and Background Technology

[0002] This invention relates to a non-rotating boring tool for internal turning as described in the preamble of claim 1. The invention also relates to boring arrangements including such boring tools.

[0003] Boring tools, including cantilevered boring bars (which have cutting elements at their free ends), can be used to perform internal turning operations on rotating workpieces of metallic material. Internal turning operations machine the inner surface of a workpiece within a hole located in the workpiece, wherein, while machining the inner surface of the hole, the boring bar gradually moves deeper and deeper into the hole. For example, internal turning operations can be performed to enlarge existing holes in a workpiece or to smooth the inner surface of such holes. During internal turning operations, the cutting element is subjected to cutting forces from the rotating workpiece, including radial forces that extend along a line perpendicular to the axis of rotation of the workpiece and intersect the axis of rotation and the contact point between the cutting element and the workpiece, and tangential forces that are perpendicular to the radial forces and tangentially oriented along the workpiece surface at the contact point between the cutting element and the workpiece. These mutually perpendicular cutting forces will cause vibrations in the boring bar, which can lead to noise, impaired workpiece surface finish, tool breakage, and other undesirable effects.

[0004] To reduce boring bar vibration caused by cutting forces on the cutting elements at the outer end of the boring bar during workpiece machining, different types of active damping systems have been developed. Such active damping systems may include at least one vibration sensor for sensing the vibration of the boring bar and at least one electrically controlled vibration actuator for generating a vibrational force in the boring bar. The vibration actuator is controlled by an electronic control unit based on measurement signals from one or more vibration sensors to introduce an anti-vibration in the boring bar that interferes with and thus counteracts the vibration caused by the cutting forces in the boring bar.

[0005] An active damping system of the type mentioned above is disclosed in US 5,170,103 A, in which a vibration actuator is housed in a cavity inside a boring bar.

[0006] Purpose of the invention

[0007] The object of the present invention is to provide a non-rotational boring tool of the type mentioned above with a new and advantageous design. Summary of the Invention

[0008] According to the present invention, the objective is achieved by means of a non-rotating boring tool having the features defined in claim 1.

[0009] The non-rotating boring tool according to the present invention is used for internal turning and includes:

[0010] - A boring bar, comprising an elongated body configured for attachment to a support structure of a metal cutting machine, the elongated body having a rear end and an opposing front end; and

[0011] - A cutting tool portion having a cutting element, wherein the cutting tool portion is detachably attached to the front end of the elongated body or integrally formed with the front end of the elongated body, the cutting element including a rake face, a flank face and a cutting edge formed at the intersection between the rake face and the flank face.

[0012] In order to allow the boring tool of the present invention to be defined in a suitable manner, the following imaginary reference line is defined in a cross section perpendicular to the longitudinal axis of the elongated body mentioned above and intersecting the cutting edge at the outermost radial point on the cutting edge:

[0013] - A straight and imaginary first reference line L1, which intersects the cutting edge at its outermost radial point and extends at an angle of 6° relative to the flank face on the outer side of the cutting element, and

[0014] A straight, imaginary second reference line L2 intersects the cutting edge at its outermost radial point and extends between the rake face and flank face at an angle of 10° to 40° relative to the first reference line L1. Preferably, the second reference line L2 extends between the rake face and flank face at an angle of 10° to 30° relative to the first reference line L1.

[0015] The boring bar includes an electrically controlled vibration actuator (hereinafter referred to as the first actuator) for active vibration damping of the boring bar and is configured to generate a vibration force parallel or substantially parallel to the working axis of the actuator, wherein the actuator is a single-axis actuator having a single working axis and is arranged in the elongated body, the working axis of which extends parallel or substantially parallel to the second reference line L2 mentioned above.

[0016] The clearance angle of the cutting element of a non-rotating boring tool used for internal turning is typically 6° or close to 6°. This means that the tangential cutting force mentioned above on the cutting element will be oriented substantially along the first reference line L1 defined above, while the radial cutting force mentioned above on the cutting element will be oriented substantially perpendicular to the first reference line L1.

[0017] Vibrations induced in the boring bar of a non-rotating boring tool during internal turning are primarily caused by the aforementioned tangential and radial cutting forces on the cutting element. These forces act on the cutting element at the contact point between the cutting element and the workpiece (i.e., the outermost radial point on the cutting edge of the cutting element). The tangential cutting force F on the cutting element... t and radial cutting force F rOriented in a plane perpendicular to the longitudinal axis of the elongated body and intersecting the contact point between the cutting element and the workpiece, i.e., in the plane corresponding to the cross-section defined above. The radial cutting force F on the cutting element. r and tangential cutting force F t The resultant force F res (see Figure 7c The resultant force has a point of application at the outermost radial point on the cutting edge and extends between the rake face and flank face of the cutting element in the same plane as the tangential and radial cutting forces (i.e., in the plane corresponding to the cross-section defined above). The resultant force F res With tangential cutting force F t The angle between them, and therefore the angle between the resultant force and the first reference line L1, depends on the tangential cutting force F. t The magnitude of the radial cutting force F r The relationship between their sizes. Furthermore, this relationship depends on the depth of cut 'a' of the cutting edge. p and corner radius r ε Based on principles well-known to those skilled in the art, simple calculations can yield the following: Under normal operating conditions of internal turning, the tangential cutting force F... t The magnitude of the radial cutting force F r The relationship between their magnitudes makes the resultant force F res With tangential cutting force F t The angle between them, and therefore the angle between the resultant force and the first reference line L1, is in the range of 10° to 40°. For example, when the cutting depth a p Make 0.5·r ε ≤a p ≤r ε At that time, the tangential cutting force F t With radial cutting force F r The ratio of their forces is approximately 2:1, which means that the resultant force F res With tangential cutting force F t The angle between them, and therefore the angle between the resultant force and the first reference line L1, is approximately 27°. When the cutting depth a p Make 2·r ε ≤a p ≤3·r ε At that time, the tangential cutting force F t With radial cutting force F r The ratio of their forces is approximately 4:1, which means that the resultant force F res With tangential cutting force F t The angle between them, and therefore the angle between the resultant force and the first reference line L1, is approximately 14°.

[0018] The orientation of the second reference line L2 is intended to represent the expected orientation of the resultant force mentioned above on the cutting element. This means that the first actuator is arranged in the elongated body with its working axis extending substantially parallel to the expected orientation of the resultant force on the cutting element. This, in turn, allows the actuator to effectively dampen vibrations caused by the combined effect of tangential and radial cutting forces on the cutting element. With this arrangement of the actuator, effective vibration damping of the boring bar can be achieved using a single actuator.

[0019] According to an embodiment of the invention, a first actuator is arranged in the elongated body such that the central axis of the first actuator is aligned or substantially aligned with the longitudinal axis of the elongated body. This achieves centering of the first actuator within the elongated body, which simplifies the calculations used in controlling the first actuator, thereby enabling a damping system with good ability to respond accurately and quickly to and dampen vibrations in the boring bar. However, alternatively, the first actuator can be arranged such that its central axis is not aligned with the longitudinal axis of the elongated body.

[0020] According to another embodiment of the invention, the first actuator is adjustable in its rotational position within the elongated body, and / or the cutting tool portion is adjustable in its rotational position relative to the elongated body. Therefore, the angular position of the first actuator relative to the cutting element can be adjusted to optimize damping characteristics, for example, depending on the cutting depth α. p .

[0021] According to another embodiment of the invention, the boring bar includes a second electrically controlled vibration actuator for active vibration damping of the boring bar. The second actuator is configured to generate a vibrational force parallel or substantially parallel to its working axis, wherein the second actuator is a single-axis actuator having a single working axis, and wherein the second actuator is arranged longitudinally in series with the first actuator in the elongated body. The second actuator assists the first actuator in damping the vibrations induced in the boring bar by the cutting force acting on the cutting element, thereby improving the damping characteristics. The first and second actuators are preferably arranged in the elongated body such that the central axes of the first and second actuators are aligned or substantially aligned with each other.

[0022] According to another embodiment of the invention, the first actuator and the second actuator are arranged such that their working axes are angularly offset from each other, preferably perpendicular to each other, and the first actuator is preferably arranged between the tool portion and the second actuator. Thus, the different actuators concentrate on counteracting vibrations in different angular directions relative to the longitudinal axis of the boring bar, which facilitates effective vibration damping.

[0023] In addition to the first and second actuators mentioned above, the boring bar may, if desired, include one or more additional vibration actuators arranged in the elongated body in any suitable manner.

[0024] According to another embodiment of the present invention, the elongated body includes:

[0025] - An elongated main portion, configured for attachment to the support structure, having a rear end and an opposing front end.

[0026] - A front portion having a rear end facing the front end of the main portion and a opposite front end, the front end of which is arranged to carry the cutting tool portion, and

[0027] - At least one damping module is arranged between the front end of the main part and the rear end of the front part, and accommodates at least one of the first actuator and the second actuator.

[0028] The front portion of the aforementioned elongated body is connected to the main portion of the elongated body via the at least one damping module, wherein the at least one damping module constitutes a length segment of the elongated body. Therefore, as seen in the longitudinal direction of the elongated body, the main portion, the at least one damping module, and the front portion constitute independent and consecutively arranged length segments of the elongated body. Thus, by first mounting the actuator within the housing of the associated damping module, and then fixing the damping module between the main portion and the front portion of the elongated body, the vibration actuator can be integrally formed in the elongated body of the boring bar, which facilitates the assembly of the boring bar. In this case, if needed, the working direction of the actuator relative to the contact point between the cutting element and the workpiece can be adjusted by adjusting the rotational position of the associated damping module relative to the front portion of the elongated body. Furthermore, by accommodating the actuator in a separate damping module, the damping characteristics can be easily adapted to specific needs by modifying the damping module without altering other parts of the boring bar. Depending on specific needs, the number of actuators in the boring bar can be easily changed by altering the number of damping modules arranged between the main and front portions of the elongated body. The arrangement of the actuators within separate damping modules between the main and front portions of the elongated body also allows for easy positioning of the actuators close to the front end of the elongated body, a favorable location for the actuators as it is close to the cutting element that generates vibrations in the boring bar. Furthermore, using separate damping modules makes this portion of the boring bar more adaptable to the actuator's requirements, maximizing the stroke of both the damping blocks and the actuators.

[0029] However, as an alternative, the elongated body of the boring bar may not have a separate damping module of the type mentioned above, in which each actuator is housed in a cavity inside the elongated body.

[0030] The main part and / or the front part and / or the at least one damping module are advantageously cylindrical, preferably cylindrical.

[0031] According to an embodiment of the invention, the outer peripheral surface of the main portion and the outer peripheral surface of the at least one damping module are flush or substantially flush with each other. Thus, the elongated body of the boring bar can be designed to have a smooth outer peripheral surface.

[0032] According to another embodiment of the invention, the at least one damping module is held between the main portion and the front portion by means of a tie rod, preferably extending through a channel in the at least one damping module. Thus, one or more damping modules can be secured between the main portion and the front portion of the elongated body in a simple and reliable manner. Each tie rod may have a first end fixed to the main portion and an opposing second end fixed to the front portion.

[0033] According to another embodiment of the invention, the elongated body includes at least two damping modules of the type mentioned above, arranged in series between the front end of the main portion and the rear end of the front portion, wherein a first actuator and a second actuator are arranged in different damping modules. Thus, the first and second actuators can be integrally formed in the elongated body of the boring bar in a simple manner. Alternatively, the first and second actuators can be housed in the same damping module. The at least two damping modules are advantageously arranged to abut against each other. However, alternatively, some intermediate element can be arranged between the at least two damping modules. The front portion of the elongated body is preferably arranged such that its rear end abuts against the front end of the foremost damping module among the at least two damping modules. However, alternatively, some intermediate element can be arranged between the front portion and the foremost damping module. The rearmost damping module among the at least two damping modules is preferably arranged such that its rear end abuts against the front end of the main portion of the elongated body. However, alternatively, some intermediate element can be arranged between the main portion and the rearmost damping module.

[0034] To facilitate the manufacture of the elongated body, the at least two damping modules advantageously have the same design and dimensions.

[0035] Other advantageous features of the boring tool according to the invention will become apparent from the following description.

[0036] The present invention also relates to a boring arrangement comprising a boring bar of the type mentioned above and an electronic control unit configured to control the current supplied to a first actuator in order to control the generation of a vibrational force in the actuator. Preferably, the boring arrangement further comprises at least one vibration sensor configured to generate a measurement signal related to the vibration of the boring bar and send the measurement signal to the electronic control unit, wherein the electronic control unit is configured to receive the measurement signal from the at least one vibration sensor and control the current supplied to the first actuator based on the measurement signal from the at least one vibration sensor in order to control the generation of a vibrational force in the first actuator based on these measurement signals. If the boring bar includes a second electrically controlled vibration actuator, the control unit may also be configured to control the current supplied to the second actuator in order to control the generation of a vibrational force in the second actuator based on the measurement signal.

[0037] The at least one vibration sensor is preferably mounted at its front end to the elongated body or to the cutting tool portion. This allows vibration to be detected near the cutting element, effectively counteracting vibrations caused by the cutting force acting on the cutting element.

[0038] Other advantageous features of the boring arrangement according to the invention will become apparent from the following description. Attached Figure Description

[0039] Referring to the accompanying drawings, embodiments of the invention, cited as examples, will be described in detail below. In the drawings:

[0040] Figure 1 This is a side view of a non-rotary boring tool according to an embodiment of the present invention.

[0041] Figure 2 It is based on Figure 1 Longitudinal cross-section of line II-II in the middle.

[0042] Figure 3 yes Figure 1 Exploded view of the boring tool.

[0043] Figure 4 yes Figure 1 An exploded view of the boring tool from another direction.

[0044] Figure 5 yes Figure 1 A three-dimensional view of the front end of a boring tool.

[0045] Figure 6 yes Figure 1 Front view of the boring tool

[0046] Figure 7a It includes from Figure 1 A perspective view above the cutting element in a boring tool.

[0047] Figure 7b From Figure 7a A three-dimensional view of the cutting element below.

[0048] Figure 7c yes Figure 7a Side view of the cutting element.

[0049] Figure 8a This is a perspective view from above the alternative cutting element.

[0050] Figure 8b From Figure 8a A three-dimensional view of the cutting element below.

[0051] Figure 8c yes Figure 8a Side view of the cutting element.

[0052] Figure 9 This is a general diagram of the boring hole arrangement according to an embodiment of the present invention.

[0053] Figure 10 This is a schematic diagram of the boring hole arrangement according to an alternative embodiment of the present invention.

[0054] Figure 11 This is a schematic diagram of the boring hole arrangement according to another alternative embodiment of the present invention.

[0055] Figure 12 This is a side view of a non-rotary boring tool according to an alternative embodiment of the present invention.

[0056] Figure 13 It is based on Figure 12 The longitudinal section of line XIII-XIII in the diagram. Detailed Implementation

[0057] exist Figures 1 to 5 The diagram illustrates a non-rotating boring tool 1 according to an embodiment of the present invention. The boring tool 1 is used to perform internal turning operations on a rotating workpiece of metallic material. The boring tool 1 includes a boring bar 2, which is fixed to a support structure 3 of a metal cutting machine (in...). Figures 9 to 11 (shown very schematically) so that it can extend cantilevered from the support structure 3. The boring bar 2 includes an elongated body 6, which is configured to attach to the support structure 3 of the metal cutting machine. The elongated body 6 has a rear end 6b and an opposing front end 6a. The longitudinal axis 7 of the elongated body extends between the rear end 6b and the front end 6a of the elongated body.

[0058] The boring tool 1 also includes a tool portion 4 provided with a cutting element 5, wherein the tool portion 4 is supported by the elongated body 6 and mounted to the elongated body at its front end 6a. Alternatively, the tool portion 4 may be integrally formed with the front end 6a of the elongated body, meaning that the tool portion 4 and the elongated body 6 are combined into a common component.

[0059] The boring bar 2 includes an electrically controlled vibration actuator 8 for active vibration damping of the boring bar 2. The actuator 8 includes a movable damping block 9 and is configured to generate a vibrational force parallel to or at least substantially parallel to the operating axis 10 of the actuator through movement of its damping block. The actuator 8 is a single-axis actuator with a single operating axis 10.

[0060] Actuator 8 is configured to generate a vibratory force to counteract the vibrations in the boring bar 2 caused by the cutting force acting on the cutting element 5 during the machining of the rotating workpiece. The vibratory force generated by actuator 8 can also be used to cause the cutting element 5 to vibrate intermittently in order to break larger metal chips cut off from the workpiece by the cutting element 5 into smaller fragments.

[0061] Actuator 8 can be of the electromagnetic type, in which the vibration force is generated electromagnetically. However, any other suitable type of vibration actuator can also be used.

[0062] The cutting element 5 fixed to the tool section 4 can be a positive cutting element (such as...). Figures 7a to 7c (as shown) or negative cutting elements (such as Figures 8a to 8c (As shown). The cutting element 5 includes a rake face 30 on its upper side, a bottom surface 31 extending parallel or substantially parallel to the rake face 30, and a flank face 32 extending outwards between the rake face 30 and the bottom surface 31. A cutting edge 33 is formed at the intersection between the rake face 30 and the flank face 32. In the illustrated example, the cutting edge 33 extends along the outer periphery of the rake face 30 around the entire rake face 30. In the case of a positive cutting element 5, as... Figure 7c As shown, the flank face 32 is at an acute angle to the rake face 30. Extension. In the case of negative cutting element 5, such as Figure 8c As shown, the flank face 32 extends at a right angle relative to the rake face 30.

[0063] A hole 34 extends through the cutting element 5 between the rake face 30 and the bottom surface 31. The cutting element 5 is configured to be releasably mounted to the tool portion 4, wherein the bottom surface 31 of the cutting element 5 rests on a support surface 35 on a tool holder provided for the cutting element in the tool portion 4 (see [link to tool holder]). Figure 6 The cutting element 5 is fastened by a screw-type fastening element 36 (see...). Figure 5The tool holder is fixed to the tool section 4, and the fastening element extends through the hole 34 in the cutting element 5 and engages with the threaded hole on the support surface 35 on the tool holder.

[0064] In the illustrated example, the cutting element 5 includes two cutting corners 37 positioned opposite each other on opposite sides of the cutting element. The cutting element 5 is fixed to the tool portion 4, wherein one of the cutting corners 37 faces outward away from the longitudinal axis 7 of the elongated body 6, and the cutting element 5 is intended to contact the rotating workpiece via this outward-facing cutting corner 37. During internal turning of the rotating workpiece, as... Figure 7c and Figure 8c As shown, the boring tool 1 is typically positioned relative to the workpiece such that the aforementioned tangential force F on the cutting element 5... t Point it at an angle θ of approximately 6° relative to the back face 32.

[0065] The imaginary first and second reference lines L1 and L2 are straight (see Figure 6 The first reference line L1 intersects the cutting edge 33 at the radially outermost point 39 within a cross section perpendicular to the longitudinal axis 7 of the elongated body 6. In this cross section, it extends at an angle β of 6° relative to the flank face 32 on the outer side of the cutting element 5; that is, this angle β is measured on the outer side of the cutting element 5. Therefore, when in… Figures 7a to 7c When the positive cutting element 5 with a 6° back angle shown is fixed to the tool portion 4, as shown... Figure 6 As shown, the first reference line L1 can extend perpendicularly to the rake face 30 of the cutting element.

[0066] The second reference line L2 intersects the cutting edge 33 at the outermost radial point 39 and extends between the rake face 30 and the flank face 32 at an angle α ranging from 10° to 40° relative to the first reference line L1.

[0067] The actuator 8 is arranged in the elongated body 6 in such a position that its working axis 10 extends parallel to or at least substantially parallel to the second reference line L2. Therefore, when viewed in the cross-section mentioned above, the working axis 10 of the actuator 8 forms an angle of 10° to 40° with respect to the first reference line L1.

[0068] The actuator 8 is preferably arranged in the elongated body 6 such that the central axis 11 of the actuator is aligned or substantially aligned with the longitudinal axis 7 of the elongated body.

[0069] The working axis 10 of the actuator 8 extends perpendicularly to its central axis 11. Furthermore, the working axis 10 of the actuator 8 extends in a cross section perpendicular to the longitudinal axis 7 of the elongated body 6.

[0070] exist Figures 1 to 5 In the illustrated embodiment, the elongated body 6 of the boring bar 2 is composed of a plurality of individual portions 12, 13, and 14, which are connected to each other and together form the elongated body 6, wherein these portions 12, 13, and 14 constitute a plurality of individual length segments (i.e., individual sections) of the elongated body 6. Thus, as viewed in the longitudinal direction of the elongated body, these portions 12, 13, and 14 constitute connecting segments of the elongated body 6 of the boring bar. In this case, the elongated body 6 includes an elongated main portion 12, which is configured to be attached to the support structure 3 of the metal cutting machine. The main portion 12 has a rear end 12b and an opposing front end 12a. The main portion 12 is preferably tubular, and it will be attached to the support structure 3 at its rear end 12b. In the illustrated embodiment, the main portion 12 is cylindrical and has a circular cross-sectional shape. However, the main portion 12 may also have any other suitable cross-sectional shape, such as, for example, an elliptical or polygonal cross-sectional shape.

[0071] exist Figures 1 to 5 The elongated body 6 shown further includes a front portion 13. This front portion 13 has a rear end 13b facing a front end 12a of the main portion 12 and an opposing front end 13a. The front end 13a of the front portion is arranged to carry the aforementioned cutting tool portion 4. Therefore, the cutting tool portion 4 is attached to the front portion 13 of the elongated body at its front end 13a. Alternatively, the cutting tool portion 4 may be integrally formed with the front portion 13, meaning that the cutting tool portion 4 and the front portion 13 are combined into a common component. In the illustrated embodiment, the front portion 13 is cylindrical and has a circular cross-sectional shape. However, the front portion 13 may also have any other suitable cross-sectional shape, such as, for example, an elliptical or polygonal cross-sectional shape.

[0072] exist Figures 1 to 5 The elongated body 6 shown also includes a damping module 14 disposed between the front end 12a of the main portion 12 and the rear end 13b of the front portion 13, wherein the damping module 14 has a rear end 14b facing the main portion 12 and an opposing front end 14a facing the front portion 13. The front portion 13 is connected to the main portion 12 via the damping module 14. In the illustrated embodiment, the damping module 14 is cylindrical and has a circular cross-sectional shape. However, the damping module 14 may also have any other suitable cross-sectional shape, such as, for example, an elliptical or polygonal cross-sectional shape.

[0073] The damping module 14 houses the actuator 8, which is disposed within the housing 15 of the damping module, and the damping block 9 of the actuator 8 is movable relative to the housing 15. In the illustrated embodiment, the damping block 9 is movable relative to the housing 15 of the damping module 14, overcoming the action of the return spring 16 disposed on the opposite side of the damping block 9.

[0074] like Figure 1 , Figure 2 and Figure 5 As shown, the outer peripheral surface 18 of the main portion 12 and the outer peripheral surface 19 of the damping module 14 are advantageously flush or substantially flush with each other. In addition, the outer peripheral surface 20 of the front portion 13 is advantageously flush or substantially flush with the outer peripheral surface 19 of the damping module 14.

[0075] To facilitate maintenance and repair of the boring bar 2, the main part 12, the damping module 14, and the front part 13 are preferably detachably mounted to each other. In the illustrated embodiment, the damping module 14 is held between the main part 12 and the front part 13 by means of a tie rod 22. Each tie rod 22 has a first end 22a fixed to the main part 12 and an opposing second end 22b fixed to the front part 13. Furthermore, each tie rod 22 extends through a channel 23 in the damping module 14. Alternatively, the different parts 12, 13, 14 of the elongated body 6 can be mounted to each other in any other suitable manner.

[0076] In the illustrated embodiment, the actuator 8 in the damping module 14 is accessible through two openings on opposite sides of the damping module, each opening being covered by a removably mounted cover 24 that forms part of the outer peripheral surface 19 of the damping module and is secured in the associated opening by means of fastening elements 25 in the form of screws. Channels 23 for some of the aforementioned pull rods 22 may be provided in the cover 24.

[0077] In the illustrated embodiment, coolant is supplied to the tool portion 4 via a first feed tube 26 and at least one second feed tube 27. The first feed tube extends axially through the main portion 12 of the extension body 6, and the second feed tube extends parallel to the pull rod 22 between the main portion 12 and the front end portion 13 of the extension body. In the illustrated example, the boring bar 2 is provided with two such second feed tubes 27. The first feed tube 26 is secured to the main portion 12 of the extension body by means of a first end member 28a and a second end member 28b. The first end member is secured to the main portion 12 at the front end 12a of the main portion, and the second end member is secured to the main portion 12 at the rear end 12b of the main portion. Each of the second feed tubes 27 is connected to the first feed tube 26 via an internal passage in the first end member 28a. Furthermore, each of the second feed tubes 27 can be arranged to extend through mutually aligned channels 29 in the damping module 14.

[0078] To allow adjustment of the angular position of the actuator 8's working axis 10 relative to the cutting element 5, the front portion 13 of the extended body 6 can be adjustable in its rotational position relative to the damping module 14. This means that the front portion 13 can be attached to the damping module 14 at different selectable rotational positions relative to the damping module. Alternatively to, or in combination with, this rotational adjustability of the front portion 13 relative to the damping module 14, the tool portion 4, on which the cutting element 5 is located, can be adjustable in its rotational position relative to the front portion 13 of the extended body. This means that the tool portion 4 can be attached to the front portion 13 at different selectable rotational positions relative to the front portion. The damping module 14 can also be arranged such that its actuator 8 can be adjustable in its rotational position relative to the housing of the damping module. The rotational position of the actuator 8 (i.e., its angular position relative to the cutting element 5) can be steplessly or progressively adjustable. The optimal rotational position of the actuator can be calculated in advance (i.e., before the start of the workpiece machining process) based on the workpiece material's cutting data and / or characteristics and / or cutting conditions. The optimal rotational position of the actuator refers to the position of its working axis relative to the resultant force F. res The rotational position of the parallel orientation. However, during the machining process, the rotational position of the actuator can also be actively and continuously controlled and adjusted (e.g., using a suitable type of motor (preferably arranged / included in the boring tool)) by an electronic control unit configured to control the current supplied to the motor in order to control and adjust the angular position of the motor, thereby adjusting the rotational position of the actuator to its optimal rotational position. The electronic control unit configured to control the current supplied to the motor can be the same electronic control unit 41 or a separate electronic control unit.

[0079] exist Figures 9 to 11 The image schematically illustrates different embodiments of a boring arrangement 40 including a boring bar 2 of the type described above. The boring arrangement 40 also includes an electronic control unit 41 configured to control the supply of current to the actuator 8 in the elongated body 6, thereby controlling the generation of vibrational forces in the actuator. Current is supplied from a power source to the actuator 8, such as... Figure 9 As shown, the power supply can be an external power supply 42, or as... Figure 11 As shown, the power supply can be a power supply unit 42' installed on the extended body 6, or as... Figure 10 As shown, the power supply can be a power supply unit 42' installed on the support structure 3 or any other part of the metal cutting machine. The power supply unit 42' includes at least one energy storage component (e.g., in the form of a battery) for storing electrical energy. The electronic control unit 41 can be installed on the front portion 13 of the elongated body 6, as shown... Figure 10 and Figure 11As shown, it can be mounted to any other part of the elongated body. Alternatively, the electronic control unit 41 can be mounted to the support structure 3 or any other part of the metal cutting machine, such as... Figure 9 As shown.

[0080] The boring arrangement 40 also includes at least one vibration sensor 43 (e.g., in the form of an accelerometer), which is configured to generate a measurement signal related to the vibration of the boring bar 2 and transmit the measurement signal to the electronic control unit 41 via a wireless or cable connection. The at least one vibration sensor 43 is preferably mounted to the front portion 13 or the cutting tool portion 4 of the elongated body 6, but alternatively, it may be mounted to any other suitable portion of the elongated body 6.

[0081] The electronic control unit 41 is configured to receive measurement signals from the at least one vibration sensor 43 and control the supply of current to the actuator 8 based on these measurement signals, so as to control the generation of vibrational force in the actuator 8 according to these measurement signals, thereby counteracting the cutting force F acting on the cutting element 5 during the machining of the workpiece. r F t Vibration caused in boring bar 2.

[0082] exist Figures 1 to 5 In the illustrated embodiment, the boring bar 2 includes only one vibration actuator 8. However, alternatively, the boring bar 2 may include one or more additional electrically controlled vibration actuators for active vibration damping of the boring bar.

[0083] exist Figure 12 and Figure 13 In the illustrated embodiment, the boring bar 2 includes a first electrically controlled vibration actuator 8a and a second electrically controlled vibration actuator 8b for active vibration damping of the boring bar 2. The first vibration actuator 8a has the same characteristics as described above. Figures 1 to 5 The actuator 8 described is of the same design and is arranged in the elongated body 6 in the same manner as the actuator 8. Therefore, the first actuator 8a is a single-axis actuator with a single working axis 10a, and it is arranged in the elongated body 6, its working axis 10a extending parallel or at least substantially parallel to the second reference line L2 mentioned above. The second actuator 8b is also a single-axis actuator with a single working axis 10b, and it may be an actuator of the same type as the first actuator 8a. The second actuator 8b is arranged longitudinally in series with the first actuator 8a in the elongated body 6. Therefore, the first actuator 8a and the second actuator 8b are arranged sequentially in the longitudinal direction of the elongated body 6, preferably with the central axis 11a of the first actuator 8a and the central axis 11b of the second actuator 8b aligned or at least substantially aligned with each other.

[0084] The first actuator 8a and the second actuator 8b are arranged such that their working axes 10a, 10b are offset from each other at an angle, preferably perpendicular to each other. Figure 12 and Figure 13 In the example shown, the second actuator 8b is arranged between the tool section 4 and the first actuator 8a. However, the first actuator 8a and the second actuator 8b are advantageously arranged in reverse order, i.e., the first actuator 8a is arranged between the tool section 4 and the second actuator 8b.

[0085] exist Figure 12 and Figure 13 In the embodiment shown, the elongated body 6 includes the components described above. Figures 1 to 5 The described type has a main part 12 and a front part 13. Figure 12 and Figure 13 The elongated body 6 shown in the figure further includes, as referenced above. Figures 1 to 5 The described type includes two damping modules 14, which are arranged in series between the front end 12a of the main portion 12 and the rear end 13b of the front portion 13. In this case, the first actuator 8a and the second actuator 8b are arranged in different damping modules 14. However, alternatively, the first actuator 8a and the second actuator 8b can be arranged in the same damping module 14.

[0086] exist Figure 12 and Figure 13 In the illustrated embodiment, the damping modules 14 are directly abutted against each other, wherein the rear end 14b of the foremost damping module abuts against the front end 14a of another damping module (i.e., the rearmost damping module). Figure 12 and Figure 13 As shown, the front portion 13 can be arranged such that its rear end 13b directly abuts against the front end 14a of the foremost damping module, and the rearmost damping module can be arranged such that its rear end 14b directly abuts against the front end 12a of the main portion 12.

[0087] When the elongated body 6 is provided with more than two vibration actuators, the elongated body may include more than two damping modules 14. When the number of damping modules 14 is two or more, they can be arranged such that their respective rotational positions can be adjustable relative to each other.

[0088] Of course, the present invention is not limited in any way to the embodiments described above. Rather, many possibilities for modifications to the invention will be apparent to those skilled in the art without departing from the basic spirit of the invention (as defined in the appended claims).

Claims

1. A non-rotating boring tool for internal turning, comprising: - A boring bar (2), the boring bar including an elongated body (6) configured for attachment to a support structure of a metal cutting machine, the elongated body (6) having a rear end (6b) and an opposing front end (6a); and - A cutting tool portion (4) is provided with a cutting element (5), wherein the cutting tool portion (4) is detachably attached to the front end (6a) of the elongated body (6) or integrally formed with the front end (6a) of the elongated body, the cutting element (5) includes a rake face (30), a flank face (32) and a cutting edge (33) formed at the intersection between the rake face and the flank face, wherein, when viewed in a cross section perpendicular to the longitudinal axis (7) of the elongated body (6) and intersecting the cutting edge (33) at the radially outermost point (39): A straight and imaginary first reference line L1 intersects the cutting edge (33) at the outermost radial point (39) and extends at an angle (β) of 6° relative to the flank face (32) on the outer side of the cutting element (5). A straight and imaginary second reference line L2 intersects the cutting edge (33) at the outermost radial point (39) and extends between the rake face (30) and the flank face (32) at an angle (α) of 10° to 40° relative to the first reference line L1. Its features are: - The boring bar (2) includes a first electrically controlled vibration actuator for active vibration damping of the boring bar (2), the first electrically controlled vibration actuator being configured to generate a vibration force parallel or substantially parallel to the working axis of the first electrically controlled vibration actuator, wherein the first electrically controlled vibration actuator is a single-axis actuator having a single working axis; - The first electrically controlled vibration actuator is arranged in the elongated body (6), and the working axis of the first electrically controlled vibration actuator extends parallel or substantially parallel to the second reference line L2. The boring bar (2) includes a second electrically controlled vibration actuator for active vibration damping of the boring bar (2). The second electrically controlled vibration actuator is configured to generate a vibration force parallel or substantially parallel to the working axis of the second electrically controlled vibration actuator. The second electrically controlled vibration actuator is a single-axis actuator with a single working axis. The second electrically controlled vibration actuator and the first electrically controlled vibration actuator are arranged longitudinally in series in the elongated body (6). - The first and second electrically controlled vibration actuators are arranged such that their working axes are offset from each other at an angle.

2. The non-rotational boring tool according to claim 1, characterized in that, The first electrically controlled vibration actuator is arranged in the elongated body (6) such that the central axis of the first electrically controlled vibration actuator is aligned or substantially aligned with the longitudinal axis (7) of the elongated body.

3. The non-rotational boring tool according to claim 1 or 2, characterized in that, The first electrically controlled vibration actuator is adjustable in its rotational position within the elongated body (6), and / or the cutter portion (4) is adjustable in its rotational position relative to the elongated body (6).

4. The non-rotational boring tool according to claim 1, characterized in that, The first and second electrically controlled vibration actuators are arranged such that their working axes are perpendicular to each other.

5. The non-rotational boring tool according to any one of claims 1 to 2, characterized in that, The first and second electrically controlled vibration actuators are arranged in the elongated body (6) such that the central axis of the first electrically controlled vibration actuator and the central axis of the second electrically controlled vibration actuator are aligned or substantially aligned with each other.

6. The non-rotational boring tool according to any one of claims 1 to 2, characterized in that: -The elongated body (6) includes: • An elongated main portion (12), the main portion being configured to attach to the support structure, the main portion (12) having a rear end (12b) and an opposing front end (12a), • Front portion (13), the front portion having a rear end (13b) facing the front end (12a) of the main portion (12) and an opposing front end (13a), the front end (13a) of the front portion (13) being arranged to carry the tool portion (4), and • At least one damping module (14), said at least one damping module being arranged between the front end (12a) of the main portion (12) and the rear end (13b) of the front portion (13), and accommodating the first electrically controlled vibration actuator and / or the second electrically controlled vibration actuator; and - The front portion (13) of the elongated body (6) is connected to the main portion (12) of the elongated body via the at least one damping module (14), wherein the at least one damping module (14) constitutes a length segment of the elongated body (6).

7. The non-rotational boring tool according to claim 6, characterized in that, The main part (12) and / or the front part (13) and / or the at least one damping module (14) are cylindrical.

8. The non-rotational boring tool according to claim 6, characterized in that, The outer peripheral surface (18) of the main part (12) and the outer peripheral surface (19) of the at least one damping module (14) are flush or substantially flush with each other.

9. The non-rotational boring tool according to claim 6, characterized in that, The at least one damping module (14) is held between the main part (12) and the front part (13) by means of a pull rod (22).

10. The non-rotational boring tool according to claim 6, characterized in that, The first electrically controlled vibration actuator and the second electrically controlled vibration actuator are housed in the same damping module (14).

11. The non-rotational boring tool according to claim 6, characterized in that, The elongated body (6) includes at least two damping modules (14) arranged in series between the front end (12a) of the main part (12) and the rear end (13b) of the front part (13), wherein the first electrically controlled vibration actuator and the second electrically controlled vibration actuator are arranged in different damping modules in the damping modules (14).

12. The non-rotational boring tool according to claim 1 or 2, characterized in that, The first electrically controlled vibration actuator is arranged between the tool section (4) and the second electrically controlled vibration actuator.

13. The non-rotational boring tool according to claim 6, characterized in that, The main part (12) and / or the front part (13) and / or the at least one damping module (14) are cylindrical.

14. The non-rotational boring tool according to claim 9, characterized in that, The tie rod extends through the channel (23) in the at least one damping module (14).

15. A boring arrangement for internal turning, characterized in that, The boring hole arrangement includes: - The non-rotating boring tool (1) according to any one of claims 1 to 14; and - Electronic control unit (41), the electronic control unit being configured to control the current supplied to the first electrically controlled vibration actuator in order to control the generation of vibration force in the first electrically controlled vibration actuator.

16. The boring hole arrangement according to claim 15, characterized in that: - The boring arrangement (40) includes at least one vibration sensor (43), which is configured to generate a measurement signal related to the vibration of the boring bar (2) and send the measurement signal to the electronic control unit (41); and - The electronic control unit (41) is configured to receive the measurement signal from the at least one vibration sensor (43), wherein the electronic control unit (41) is configured to control the current to the first electrically controlled vibration actuator according to the measurement signal from the at least one vibration sensor (43), so as to control the generation of vibration force in the first electrically controlled vibration actuator according to the measurement signal.

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