Friction Welding Machine

Abstract

The present invention relates to a friction welding machine, which includes a base frame (10), a fixed spindle (20), a rotating spindle (30), an X-axis transfer unit (40), a Y-axis transfer unit (50), a rotary drive unit (60), an electric cylinder (70), a load cell (80), and a controller (90) to ensure consistent joining quality under various working conditions through a control structure that detects the temperature of the friction part and the axial load applied to the workpiece in real time during the friction welding process and controls the rotational speed of the rotating spindle and the axial thrust applied by the electric cylinder based on the detected values ​​to precisely control the entire friction welding process, and simultaneously distinguishes rotational conditions according to the friction stage, the stage after joining completion, and the cooling stage to implement a rotational state suitable for each process stage, and determines whether welding is completed based on at least one of the friction part temperature, axial thrust, and pressurization time.

Description

Technology Field

[0001] The present invention relates to a friction welding machine that joins a pair of workpieces to be welded together using frictional heat. More specifically, the invention relates to a friction welding machine capable of detecting and controlling the temperature and axial load of the friction part generated during the friction welding process in real time, switching rotation conditions according to the stage of the welding process, and further performing post-welding processing continuously within a single device. Background Technology

[0003] In general, friction welding is a welding method that achieves a joint by applying axial pressure after plasticizing the materials through frictional heat generated at the contact surface by pressing a rotating workpiece on one side against an opposing workpiece. Due to its advantages over fusion welding, such as a smaller heat-affected zone, the ability to join dissimilar metals, and superior joint strength, friction welding is widely applied in the manufacturing of pipes, shafts, and various structural components.

[0004] In this regard, Registered Patent No. 10-2021093 discloses a technology in which a head stock and a tail stock are placed on a bed, and an outer casing, a male threaded tube, and a bottom plate are integrated by simultaneous friction welding. The aforementioned Prior Art Document 1 focuses on improving work efficiency and productivity by precisely centering the workpiece using a distance sensor and a positioning plate. However, this technology does not disclose a configuration that actively controls rotational speed or axial thrust by detecting the temperature of the friction part generated during the friction welding process in real time, and has limitations in that welding conditions are applied uniformly according to pre-set values. As a result, variations in welding quality may occur depending on changes in the type or dimensions of the material or the contact state.

[0005] In addition, another prior art, Registered Patent No. 10-2549664, discloses a technology that enables simultaneous friction welding of different base materials on both sides of a single base material by controlling the phases of transport and rotation while rotating the two workpieces on each side. While the aforementioned prior art document 2 is advantageous for shortening processing time and improving productivity by joining multiple workpieces simultaneously, it is based on a structure in which rotation conditions are always maintained at the same phase, and therefore does not include a control concept for switching the rotation state according to the friction stage and the stage after joining is completed. In particular, the technical concept of performing the optimization of friction conditions during the friction stage and the stabilization control after joining is completed separately is not disclosed. Prior art literature

[0007] (Patent Document 0001) KR 10-2021093 B1(Patent Document 0002) KR 10-2549664 B1 The problem to be solved

[0008] Accordingly, the present invention was conceived to solve the aforementioned problems, and aims to provide a friction welding machine capable of precisely controlling the entire friction welding process by detecting the temperature of the friction part and the axial load applied to the workpiece in real time during the friction welding process and controlling the rotational speed of the rotating spindle part and the axial thrust applied by the electric cylinder in conjunction based on the detected values, while simultaneously implementing a rotational state suitable for each process stage by distinguishing rotational conditions according to the friction stage, the stage after joining completion, and the cooling stage, and ensuring consistent joining quality even under various working conditions through a control structure that determines whether welding is complete based on at least one of the friction part temperature, axial thrust, and pressurization time, and furthermore, enabling cutting the weld part while maintaining the rotating spindle part and the fixed spindle part in a synchronous rotational state at the same rotational speed and in the same rotational direction during the cooling section after welding completion. means of solving the problem

[0010] To achieve this purpose, the features of the present invention include a friction welding machine for friction welding a pair of workpieces (A) to be welded together, comprising: a fixed spindle part (20) installed on a base frame (10) to rotatably support one workpiece (A); a rotating spindle part (30) positioned opposite to the fixed spindle part (20) to rotate the other workpiece (A); an X-axis transfer part (40) for linearly transferring the rotating spindle part (30) in the X-axis direction; a Y-axis transfer part (50) for adjusting the position of the rotating spindle part (30) in the Y-axis direction; a rotational drive part (60) for providing rotational force to the rotating spindle part (30); an electric cylinder (70) coupled to the X-axis transfer part (40) to generate an axial thrust applied to the workpiece (A) simultaneously with transferring in the X-axis direction; and a load cell (80) installed at the operating end of the electric cylinder (70) to detect the axial thrust. The apparatus includes a controller (90) that controls the thrust of the electric cylinder (70) based on a load signal detected from the load cell (80) and simultaneously controls the rotational speed and pressure time of the workpiece (A); wherein the X-axis transfer unit (40) includes an LM guide (41) and a ball screw assembly (42), and the electric cylinder (70) is driven by a servo motor (71) and configured to perform position control and thrust control simultaneously.

[0011] At this time, the rotating spindle part (30) is configured to include a rotating shaft (31) and a bearing housing (32) fixedly installed on the base frame (10) to support the rotating shaft (31), and the bearing housing (32) is formed to include a plurality of bearings (33) to support the radial load and axial load applied to the rotating shaft (31) under conditions where an axial thrust generated by the electric cylinder (70) and detected in real time by the load cell (80) acts on the rotating shaft (31), and the rotating drive part (60) is configured to transmit rotational force to the rotating shaft (31) through a power transmission means (61) including a pulley and a belt or coupling, while not being directly connected to the rotating shaft (31) and being spaced apart from the bearing housing (32).

[0012] Additionally, a temperature sensor (88) is installed in the rotating spindle section (30) or the fixed spindle section (20) to detect the temperature of the contact area between the workpiece (A) during the friction welding process, and the temperature sensor (88) is configured to detect the friction part temperature in real time by being positioned in close proximity to the rotating shaft (31) or the workpiece (A), and the controller (90) is configured to control the rotational speed of the rotary drive section (60) and the axial thrust applied by the electric cylinder (70) together based on the temperature detection value input from the temperature sensor (88).

[0013] Additionally, the fixed-side spindle part (20) is further provided with a fixed-side spindle drive part (82) for rotating the fixed-side spindle part (20), and the front-side spindle drive part (82) of the front-side spindle part (30) is configured to control the fixed-side spindle part (20) to rotate in a direction opposite to the rotation direction of the rotating-side spindle part (30) during the friction step in which friction welding is performed.

[0014] Additionally, the controller (90) is configured to control the fixed-side spindle drive unit (82) under conditions where the rotation of the rotating-side spindle unit (30) is maintained after at least one of the friction part temperature detected by the temperature sensor (88), the axial thrust detected by the load cell (80), and the pressurization time satisfies a preset welding completion judgment condition, so that the fixed-side spindle unit (20) rotates at the same rotational speed and in the same rotational direction as the rotating-side spindle unit (30), and the controller (90) is characterized by controlling the rotating-side spindle unit (30) and the fixed-side spindle unit (20) to stop simultaneously when the temperature detection value detected by the temperature sensor (88) reaches a preset cooling completion reference temperature.

[0015] Additionally, the controller (90) controls the cutting bit (84) for cutting the weld formed by friction welding to be moved to a position corresponding to the weld during the cooling progress section, in which the temperature detection value detected by the temperature sensor (88) reaches a preset cutting start reference temperature and before reaching the cooling completion reference temperature, while maintaining the condition that the rotating spindle part (30) and the fixed spindle part (20) rotate at the same rotational speed and in the same rotational direction, wherein the cutting bit (84) is mounted on a cutting bit support part (85) and the cutting bit support part (85) is configured to be moved in the direction of the weld by a cutting transfer part (86).

[0016] Additionally, the load cell (80) is provided to be connected to the operating end of the electric cylinder (70) by a cell joint module (100), and the cell joint module (100) comprises a male screw portion (110) formed at the end of the load rod (72) of the electric cylinder (70), a joint housing (120) installed in the X-axis transfer unit (40) and having a compartment (121) formed inside to accommodate the load cell (80), and a load hole (122) penetrating one side of the compartment (121) to insert the male screw portion (110), a press block (130) having a press surface (131) on one side to press the load cell (80) and having a female screw portion (132) formed at the other end to be screw-fastened to the male screw portion (110), and a pitch that is screw-fastened to the male screw portion (110). It includes a joint nut (140) that is pressure-constrained toward the press block (130) by transfer and accommodated within the load hole (122), and the press block (130) is moved by the load rod (72) of the electric cylinder (70) while being accommodated within the compartment (121) of the joint housing (120) to press the load cell (80) and simultaneously press the X-axis transfer unit (40). Effects of the invention

[0018] According to the above configuration and operation, the present invention detects the temperature of the friction part and the axial load applied to the workpiece in real time during the friction welding process, and controls the rotational speed of the rotating spindle part and the axial thrust applied by the electric cylinder in conjunction based on the detected values, thereby precisely controlling the entire friction welding process. At the same time, it distinguishes rotational conditions according to the friction stage, the stage after joining completion, and the cooling stage to implement a rotational state suitable for each process stage, and through a control structure that determines whether welding is complete based on at least one of the friction part temperature, axial thrust, and pressurization time, it ensures consistent joining quality even under various working conditions. Furthermore, it enables cutting the welded part while maintaining the rotating spindle part and the fixed spindle part in a synchronous rotational state at the same rotational speed and in the same rotational direction during the cooling section after welding completion, thereby having the effect of continuously performing the friction welding process and the post-processing process within a single device. Brief explanation of the drawing

[0020] FIG. 1 is a perspective view showing the friction welding machine according to one embodiment of the present invention in its entirety. FIG. 2 is a configuration diagram showing a friction welding machine according to an embodiment of the present invention from the front. FIG. 3 is a planar view of a friction welding machine according to an embodiment of the present invention. FIG. 4 is a cross-sectional view along line AA of FIG. 2. Fig. 5 is a cross-sectional view along line BB of Fig. 3. Fig. 6 is a cross-sectional view along the CC line of Fig. 3. The present invention 7 is a configuration diagram showing a temperature sensor and a cutting bit of a friction welding machine according to an embodiment of the invention. FIG. 8 is a configuration diagram showing a cell joint module of a friction welding machine according to an embodiment of the present invention. Specific details for implementing the invention

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Furthermore, in describing the present invention, detailed descriptions of related known functions are omitted if they are deemed obvious to those skilled in the art and could unnecessarily obscure the essence of the invention.

[0022] FIG. 1 is a perspective view showing the friction welder according to an embodiment of the present invention in its entirety, FIG. 2 is a configuration diagram showing the friction welder according to an embodiment of the present invention from the front view, FIG. 3 is a configuration diagram showing the friction welder according to an embodiment of the present invention in a plan view, FIG. 4 is a cross-sectional view along line AA of FIG. 2, FIG. 5 is a cross-sectional view along line BB of FIG. 3, FIG. 6 is a cross-sectional view along line CC of FIG. 3, FIG. 7 is a configuration diagram showing the temperature sensor and cutting bit of the friction welder according to an embodiment of the present invention, and FIG. 8 is a configuration diagram showing the cell joint module of the friction welder according to an embodiment of the present invention.

[0023] The present invention relates to a friction welding machine, which includes a base frame (10), a fixed spindle (20), a rotating spindle (30), an X-axis transfer unit (40), a Y-axis transfer unit (50), a rotary drive unit (60), an electric cylinder (70), a load cell (80), and a controller (90) to ensure consistent joining quality under various working conditions through a control structure that detects the temperature of the friction part and the axial load applied to the workpiece in real time during the friction welding process and controls the rotational speed of the rotating spindle and the axial thrust applied by the electric cylinder based on the detected values ​​to precisely control the entire friction welding process, and simultaneously distinguishes rotational conditions according to the friction stage, the stage after joining completion, and the cooling stage to implement a rotational state suitable for each process stage, and determines whether welding is completed based on at least one of the friction part temperature, axial thrust, and pressurization time.

[0024] The base frame (10) according to the present invention is a basic structure that supports the entire friction welding machine and is configured to have a fixed-side spindle part (20), a rotating-side spindle part (30), an X-axis transfer part (40), a Y-axis transfer part (50), a rotary drive part (60), an electric cylinder (70), and a controller (90) installed on the upper part.

[0025] The above base frame (10) is formed of a high-rigidity metal material and is designed so that structural deformation is minimized against vibrations, axial loads, and reaction forces that occur during a long-duration friction welding process.

[0026] In addition, a reference surface and a fastening part are formed on the upper surface of the base frame (10) so that each component can be precisely aligned and firmly fixed, so that the reference posture of the entire device is stably maintained even during the rotation of the rotating spindle part (30), the application of axial thrust by the electric cylinder (70), and the switching of the rotation or fixed state of the fixed spindle part (20) during the friction welding process.

[0027] As a result, each component continuously maintains an accurate relative positional relationship, suppresses alignment errors at the joint during friction welding, and ensures a uniform bonded state even in repetitive processes.

[0028] In addition, the fixed-side spindle portion (20) according to the present invention is installed on the base frame (10) and configured to rotatably support one side workpiece (A).

[0029] The fixed-side spindle section (20) includes a chuck structure or a fixing jig capable of precisely fixing the workpiece (A) with respect to the axis, and is installed on a base frame (10) so as to be positioned opposite to the rotating-side spindle section (30).

[0030] In addition, the fixed-side spindle part (20) is configured to be coupled with a fixed-side spindle drive part (82) to enable rotational driving.

[0031] Accordingly, the fixed-side spindle part (20) can be controlled to rotate by the fixed-side spindle drive part (82) or to rotate in the opposite direction to the rotating-side spindle part (30) during the friction phase, thereby bringing the workpiece (A) into contact with the rotating-side workpiece (A) in a relative rotational state. Through this selective switching of rotational states, the relative rotational conditions required during the friction phase and the stabilization conditions after the completion of joining are implemented step by step.

[0032] In addition, the rotating spindle part (30) according to the present invention is installed on the base frame (10) as a component for rotating the other workpiece (A).

[0033] In FIG. 5, the rotating spindle portion (30) is configured to include a rotating shaft (31) and a bearing housing (32) fixedly installed on a base frame (10) to support the rotating shaft (31), and a plurality of bearings (33) are arranged inside the bearing housing (32) to stably support radial and axial loads applied to the rotating shaft (31).

[0034] For example, friction welding can be performed by contact and friction between workpieces (A) while the fixed spindle part (20) rotates with the rotating spindle part (30) in a stationary state, and subsequently, the workpiece (A) rotated by the fixed spindle part (20) can be configured to be friction welded at a different position while the rotating spindle part (30) is pivoted at a predetermined angle. At this time, the axial thrust applied by the electric cylinder (70) acts directly on the rotation axis (31), and the resulting reaction force is distributed and supported through the bearing housing (32) and bearing (33), thereby maintaining the stability of the rotation system.

[0035] In another embodiment, the rotating spindle portion (30) is driven by a rotary drive portion (60) to rotate at high speed and is moved in the direction of the fixed spindle portion (20) by an X-axis transfer portion (40), thereby causing contact and friction between the workpieces (A). At this time, the axial thrust applied by the electric cylinder (70) acts directly on the rotation axis (31), and the resulting reaction force is distributed and supported through the bearing housing (32) and the bearing (33), thereby maintaining the stability of the rotation system.

[0036] In FIG. 4, the X-axis transfer unit (40) according to the present invention is configured to include an LM guide (41) and a ball screw assembly (42) as components for linearly transferring the rotating spindle unit (30) in the X-axis direction.

[0037] The above X-axis transfer unit (40) guides the rotating spindle unit (30) to move linearly toward the fixed spindle unit (20) and is coupled with an electric cylinder (70) to simultaneously perform position control and axial thrust application.

[0038] Under the control of the above controller (90), the rotating spindle unit (30) moves forward or backward precisely, and the contact pressure and joining position between the workpieces (A) during the friction stage are finely controlled. Meanwhile, the Y-axis transfer unit (50) is a component for adjusting the position of the rotating spindle unit (30) in the Y-axis direction, enabling initial position alignment and axis correction of the workpieces (A), thereby ensuring the precision of the joining position before the start of the friction welding process.

[0039] In addition, the rotary drive unit (60) according to the present invention is a component for providing rotational force to the rotary spindle unit (30).

[0040] The above-mentioned rotary drive unit (60) is configured to transmit rotational force through a power transmission means (61) including a pulley and a belt or coupling, while being spaced apart from the bearing housing (32) and not directly connected to the rotary shaft (31).

[0041] With this arrangement, the axial load applied by the electric cylinder (70) is suppressed from being transmitted to the rotary drive unit (60), and load concentration in the drive system is prevented.

[0042] In addition, the electric cylinder (70) according to the present invention is coupled to the X-axis transfer unit (40) and configured to generate an axial thrust applied to the workpiece (A) simultaneously with transfer in the X-axis direction.

[0043] In FIG. 6, the electric cylinder (70) is driven by a servo motor (71) to simultaneously perform position control and thrust control, and a load cell (80) is installed at the actuation end to detect axial thrust in real time. The load signal output from the load cell (80) is input to a controller (90) to precisely control the thrust magnitude and holding time of the electric cylinder (70).

[0044] In this way, the electric cylinder (70) is driven by a servo motor (71) so that position control and thrust control are performed simultaneously, thereby ensuring that the transfer position of the rotating spindle (30) and the axial thrust applied to the workpiece (A) during the friction welding process are not separated from each other and are precisely managed in conjunction.

[0045] In addition, a load cell (80) is installed at the operating end of the electric cylinder (70) so that axial thrust is detected in real time and the corresponding load signal is directly input to the controller (90), thereby enabling closed-loop control based on the actual applied load rather than simple output control based on the set value.

[0046] Accordingly, instantaneous fluctuations in thrust or changes in contact conditions are immediately corrected, ensuring that the pressure conditions required during the friction phase are stably maintained and suppressing the possibility of bonding defects caused by excessive or insufficient pressure during the bonding process. Furthermore, by precisely controlling not only the magnitude of the thrust but also the holding time, the plastic flow range required according to the material or cross-sectional conditions of the workpiece (A) is stably secured, and process control is achieved in a direction that improves the reproducibility of the bonding state even in repetitive processes.

[0047] In addition, the temperature sensor (88) according to the present invention is installed on the rotating spindle part (30) or the fixed spindle part (20) and configured to detect the temperature of the contact area between the workpieces (A) in real time during the friction welding process.

[0048] In FIG. 7, the temperature sensor (88) is positioned in close proximity to the rotation axis (31) or the workpiece (A) to precisely detect changes in the temperature of the friction part, and the controller (90) controls the rotational speed of the workpiece (A) and the axial thrust applied by the electric cylinder (70) in conjunction based on the detected temperature value.

[0049] In this way, the temperature sensor (88) is positioned in close proximity to the rotation axis (31) or the workpiece (A) to directly detect changes in the temperature of the friction part, thereby transmitting the thermal state formed in the actual joint during the friction welding process to the controller (90) without delay or distortion. Accordingly, the controller (90) can control the rotational speed of the rotary drive unit (60) and the axial thrust applied by the electric cylinder (70) in conjunction with each other based on the real-time temperature detection value rather than an indirect estimated value, and the rotational condition and the pressurization condition are not changed independently but are adjusted simultaneously to reflect the same process state.

[0050] Due to this control relationship, when the temperature of the friction part deviates from the target range, the rotational speed or axial thrust is immediately corrected to suppress excessive overheating or heat deficiency, and stable plastic flow and the formation of a uniform bond structure are induced throughout the bonding process. As a result, even if there are differences in the material or shape of the workpiece (A) or minute changes in contact conditions, deviations in bonding quality are mitigated, and process control is performed in a direction that maintains a consistent welding state even in repeated processes.

[0051] In addition, the fixed-side spindle drive unit (82) according to the present invention is a component for rotating the fixed-side spindle unit (20), and is controlled so that the fixed-side spindle unit (20) rotates in the opposite direction to the rotating-side spindle unit (30) during the friction stage. Accordingly, a relative rotation condition is formed during the friction stage, and a rotation condition can be switched in the subsequent stage.

[0052] Additionally, the controller (90) according to the present invention is configured to switch rotation conditions when at least one of the friction part temperature detected by the temperature sensor (88), the axial thrust detected by the load cell (80), and the pressurization time of the electric cylinder (70) satisfies a preset welding completion judgment condition.

[0053] At this time, the controller (90) controls the fixed-side spindle drive unit (82) while maintaining the rotation of the rotating-side spindle unit (30) to synchronize control so that the fixed-side spindle unit (20) rotates at the same rotational speed and in the same rotational direction as the rotating-side spindle unit (30), and subsequently, when the temperature detection value detected by the temperature sensor (88) reaches a preset cooling completion reference temperature, the rotating-side spindle unit (30) and the fixed-side spindle unit (20) are stopped simultaneously.

[0054] In this manner, the controller (90) controls the fixed-side spindle drive unit (82) while maintaining the rotation of the rotating-side spindle unit (30) to synchronously rotate the fixed-side spindle unit (20) at the same rotational speed and in the same rotational direction. As a result, after the friction welding is completed, no additional shear force or torsional stress due to relative rotation acts on the joint, and the weld structure formed immediately after joining is maintained in a stable state without external force disturbance.

[0055] By maintaining this synchronous rotation state and controlling the temperature detection value from the temperature sensor (88) until it reaches the cooling completion reference temperature, the cooling process of the weld joint proceeds gradually without sudden rotational cessation or uneven stress relief, thereby alleviating the concentration of residual stress inside the joint. Subsequently, the operation of simultaneously stopping the rotating spindle (30) and the fixed spindle (20) prevents changes in the relative positions of the workpieces on both sides and ensures that the process ends when the joint is completely stabilized, resulting in the securing of both joint reliability and shape stability.

[0056] Additionally, the controller (90) controls the cutting process to be performed when the temperature detection value detected by the temperature sensor (88) in the cooling progress section reaches a preset cutting start reference temperature and is before reaching a cooling completion reference temperature.

[0057] At this time, the rotating spindle section (30) and the fixed spindle section (20) are maintained under conditions of synchronous rotation at the same rotational speed and in the same rotational direction, and the cutting bit (84) is mounted on the cutting bit support section (85) and is moved in the direction of the weld section by the cutting feed section (86), and contacts the weld section in a rotating state to cut the bead or protrusion formed by friction welding.

[0058] In this way, by maintaining a state in which the rotating spindle part (30) and the fixed spindle part (20) rotate synchronously at the same rotational speed and in the same rotational direction, torsional loads or additional frictional heat due to relative rotation are not generated in the welded part contacted by the cutting tool (84), and accordingly, the phenomenon of the bonding structure inside the welded part being disturbed or microcracks being induced during the cutting process is suppressed.

[0059] In addition, as the cutting bit (84) approaches the cutting feed unit (86) while the weld is maintained in a rotated state, the cutting resistance is uniformly distributed in the circumferential direction, and the bead or protrusion is removed without eccentricity, thereby stably shaping the outer edge of the weld. Furthermore, since the cutting process is performed using the section where cooling proceeds in the high-temperature state immediately after friction welding, the processing is carried out before the material hardens, thereby reducing the cutting load and mitigating tool wear. Additionally, welding and shape shaping can be continuously completed within the same device without the need for separate post-processing steps or equipment transfer. Through this series of operations, the reliability of the joining quality is maintained, while process efficiency and work consistency are simultaneously ensured.

[0060] In FIG. 8, the load cell (80) according to the present invention is not directly coupled to the working end of the electric cylinder (70), but is configured to be mechanically connected to the load rod (72) of the electric cylinder (70) by the cell joint module (100).

[0061] The cell joint module (100) forms a connection structure that allows the axial thrust applied by the electric cylinder (70) to be stably transmitted to the load cell (80) and, at the same time, the thrust to be transmitted in a consistent direction toward the X-axis transfer unit (40).

[0062] The cell joint module (100) comprises a male screw portion (110) formed at the end of the load rod (72) of the electric cylinder (70), a joint housing (120) installed in the X-axis transfer portion (40) and having a compartment (121) formed inside, with a load hole (122) formed through one side of the compartment (121) to allow the male screw portion (110) to be inserted, a press block (130) having a press surface (131) on one side to press the load cell (80) and a female screw portion (132) formed on the other end to be screw-fastened to the male screw portion (110), and a joint nut (140) that is screw-fastened to the male screw portion (110), is pressure-constrained toward the press block (130) by pitch transfer, and is received within the load hole (122).

[0063] Structurally, the joint housing (120) is fixedly installed on one side of the X-axis transfer unit (40) and serves as a reference housing through which the load rod (72) of the electric cylinder (70) can move in and out in a straight direction, and the compartment (121) formed inside is formed so that the load cell (80) can be accommodated while protected from external forces or uneven loads.

[0064] The above press block (130) is screw-coupled to the load rod (72) of the electric cylinder (70) while placed inside the compartment (121), and the press surface (131) is positioned to be in direct contact with one side of the load cell (80).

[0065] The joint nut (140) is configured to positionally restrain the press block (130) inside the joint housing (120) while fastened to the male screw portion (110), and to set the initial pressurized state of the press block (130) through fine positional adjustment according to the screw pitch.

[0066] When the operation is performed, the electric cylinder (70) is driven and the load rod (72) advances, and the press block (130) connected to the male screw portion (110) moves linearly inside the compartment (121) of the joint housing (120), and during this process, the press surface (131) directly presses the load cell (80) in the axial direction. The load cell (80) detects the axial load applied by the press block (130) in real time and outputs it to the controller (90), and at the same time, the thrust transmitted through the press block (130) is transmitted to the X-axis transfer portion (40) via the joint housing (120) to contribute to the transfer and pressurization operation of the rotating spindle portion (30). At this time, the joint nut (140) suppresses the detachment or play of the press block (130) so that the load transmission state is maintained constant even during the repeated pressurization process.

[0067] In this way, the load rod (72) of the electric cylinder (70), the load cell (80), and the X-axis transfer unit (40) are configured to be linked as a single unit on a linear axis through the cell joint module (100), so that the axial thrust generated by the electric cylinder (70) is accurately transmitted to the load cell (80) without loss or distortion and is simultaneously stably distributed and transmitted to the transfer system. Accordingly, the load cell (80) can output a load signal that directly reflects the axial load applied to the actual workpiece (A), and the controller (90) can precisely perform thrust control based on the load signal. In addition, due to the mechanical restraint structure by the press block (130) and the joint nut (140), play or eccentricity in the load transfer path is suppressed even during the repetitive pressing and releasing process, thereby stably ensuring the reliability and reproducibility of axial load detection throughout the friction welding process.

[0068] As described above, the detailed description of the present invention has explained the most preferred embodiment of the present invention, but various modifications are possible within the scope of the technical scope of the present invention. Accordingly, the scope of protection of the present invention should not be limited to the above embodiment, but should be recognized to include the technologies of the claims described below and equivalent technical means derived from these technologies. Explanation of the symbols

[0070] 10: Base frame 20: Fixed side spindle section 30: Rotating side spindle section 40: X-axis feed section 50: Y-axis transfer unit 60: Rotary drive unit 70: Electric cylinder 80: Load cell 90: Controller

Claims

Claim 1 A friction welding machine for friction welding a pair of workpieces (A) to be welded together, comprising: a fixed spindle part (20) installed on a base frame (10) to rotatably support one workpiece (A); a rotating spindle part (30) positioned opposite to the fixed spindle part (20) to rotate the other workpiece (A); an X-axis transfer part (40) for linearly transferring the rotating spindle part (30) in the X-axis direction; a Y-axis transfer part (50) for adjusting the position of the rotating spindle part (30) in the Y-axis direction; a rotational drive part (60) for providing rotational force to the rotating spindle part (30); an electric cylinder (70) coupled to the X-axis transfer part (40) to generate an axial thrust applied to the workpiece (A) simultaneously with X-axis transfer; and a load cell (80) installed at the operating end of the electric cylinder (70) to detect the axial thrust. and a controller (90) that controls the thrust of the electric cylinder (70) based on a load signal detected from the load cell (80) and simultaneously controls the rotational speed and pressurization time of the workpiece (A); The electric cylinder (70) is configured to be driven by a servo motor (71) so as to perform position control and thrust control simultaneously, and the rotating spindle part (30) is configured to include a rotating shaft (31) and a bearing housing (32) fixedly installed on the base frame (10) to support the rotating shaft (31), and the bearing housing (32) is formed to include a plurality of bearings (33) to support radial loads and axial loads applied to the rotating shaft (31) under conditions where axial thrust generated by the electric cylinder (70) and detected in real time by the load cell (80) acts on the rotating shaft (31), and the rotary drive part (60) is configured to transmit rotational force to the rotating shaft (31) through a power transmission means (61) including a pulley and a belt or coupling while spaced apart from the bearing housing (32).A temperature sensor (88) for detecting the temperature of the contact area between the workpiece (A) during the friction welding process is installed in the rotating spindle section (30) or the fixed spindle section (20), and the temperature sensor (88) is configured to detect the friction section temperature in real time by being positioned in close proximity to the rotating shaft (31) or the workpiece (A). The controller (90) is configured to control the rotational speed of the rotating drive section (60) and the axial thrust applied by the electric cylinder (70) together based on the temperature detection value input from the temperature sensor (88). Additionally, a fixed spindle drive section (82) for rotating the fixed spindle section (20) is provided in the fixed spindle section (20), and the fixed spindle drive section (82) is configured to control the fixed spindle section (20) to rotate in the opposite direction to the rotational direction of the rotating spindle section (30) during the friction stage in which friction welding is performed. A friction welding machine characterized in that the controller (90) controls the fixed-side spindle drive unit (82) under conditions where the rotation of the rotating-side spindle unit (30) is maintained after at least one of the friction part temperature detected by the temperature sensor (88), the axial thrust detected by the load cell (80), and the pressurization time satisfies a preset welding completion judgment condition, so that the fixed-side spindle unit (20) rotates at the same rotational speed and in the same rotational direction as the rotating-side spindle unit (30), and the controller (90) controls the rotating-side spindle unit (30) and the fixed-side spindle unit (20) to stop simultaneously when the temperature detection value detected by the temperature sensor (88) reaches a preset cooling completion reference temperature. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 In claim 1, the controller (90) controls the cutting bit (84) for cutting a weld formed by friction welding to be moved to a position corresponding to the weld during the cooling progress section, in which the temperature detection value detected by the temperature sensor (88) reaches a preset cutting start reference temperature and before reaching the cooling completion reference temperature, while maintaining the condition that the rotating side spindle part (30) and the fixed side spindle part (20) rotate at the same rotational speed and in the same rotational direction, wherein the cutting bit (84) is mounted on a cutting bit support part (85) and the cutting bit support part (85) is configured to be moved in the direction of the weld by a cutting transfer part (86). Claim 7 In claim 6, the load cell (80) is configured to be connected to the operating end of the electric cylinder (70) by a cell joint module (100), and the cell joint module (100) comprises: a male screw portion (110) formed at the end of the load rod (72) of the electric cylinder (70); a joint housing (120) installed in the X-axis transfer unit (40), having a compartment (121) formed inside to accommodate the load cell (80), and a load hole (122) penetrating one side of the compartment (121) to insert the male screw portion (110); a press block (130) having a press surface (131) on one side to press the load cell (80) and a female screw portion (132) formed at the other end to be screw-fastened to the male screw portion (110); and a screw on the male screw portion (110). A friction welding machine characterized by including a joint nut (140) that is connected, pressed and restrained toward the press block (130) by pitch transfer, and received within a load hole (122), wherein the press block (130) is moved by a load rod (72) of an electric cylinder (70) while being received within a compartment (121) of a joint housing (120) to press the load cell (80) and simultaneously press the X-axis transfer unit (40).

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