A friction stir welding spindle and welder

Abstract

This invention discloses a friction stir welding spindle and welding machine, comprising a machine body, a rotating shaft, and a retraction shaft assembly. The rotating shaft is mounted on the machine body via a rotating shaft bearing and has an inner core hole. The end of the rotating shaft has a stirring shoulder. The retraction shaft assembly includes a retraction shaft and a retraction shaft bearing housing. The retraction shaft is disposed within the inner core hole and is engaged with the rotating shaft via a transmission pair, enabling the retraction shaft to rotate synchronously with the rotating shaft and float axially. The end of the retraction shaft has a stirring pin that extends outward from the stirring shoulder. The retraction shaft bearing housing is disposed within the inner core hole and has a clearance fit with it. The retraction shaft extends into the retraction shaft bearing housing and is supported by the retraction shaft bearing housing. This structural design allows the retraction shaft assembly to use a larger-sized retraction shaft bearing, thereby giving the retraction shaft high axial rigidity and improving welding quality and speed.

Description

Technical Field

[0001] This invention relates to the field of friction stir welding technology, and in particular to a friction stir welding spindle and welding machine. Background Technology

[0002] Friction stir welding (FSW) technology boasts advantages such as high welding speed, small heat-affected zone, minimal welding deformation, and high weld strength, leading to its widespread application in manufacturing. However, conventional FSW welding often leaves a keyhole at the weld end, affecting aesthetics and workpiece formability. FSW spindles with a retraction function can solve this keyhole problem, thus gaining increasingly widespread use.

[0003] As friction stir welding technology is widely used in various fields, the requirements for high precision and high rigidity of the spindle are gradually increasing, enabling friction stir welding spindles to weld materials with higher hardness while achieving higher welding quality and welding speed.

[0004] Existing friction stir welding spindles suffer from structural design flaws, resulting in insufficient axial and radial rigidity, which limits welding quality and welding speed. Summary of the Invention

[0005] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a friction stir welding spindle and welding machine.

[0006] The technical solution adopted by this invention to solve its technical problem is: In a first aspect, a friction stir welding spindle includes a body, a rotating shaft, and a retraction shaft assembly. The rotating shaft is mounted on the body via a rotating shaft bearing. The rotating shaft has an inner core hole and a stirring shoulder at its end. The retraction shaft assembly includes a retraction shaft and a retraction shaft bearing housing. The retraction shaft is disposed in the inner core hole and is engaged with the rotating shaft via a transmission pair, enabling the retraction shaft to rotate synchronously with the rotating shaft and float axially. The end of the retraction shaft is provided with a stirring needle that can extend outward from the stirring shoulder. The retraction shaft bearing housing is disposed in the inner core hole and has a clearance fit with the inner core hole. The retraction shaft extends into the retraction shaft bearing housing and is supported by the retraction shaft bearing housing.

[0007] In conjunction with the first aspect, in some implementations of the first aspect, the inner hole of the shaft core includes a first hole section and a second hole section along the axial direction, the inner diameter of the first hole section is larger than the inner diameter of the second hole section, the retraction shaft bearing seat is disposed in the first hole section, and the retraction shaft and the rotating shaft cooperate with each other in the second hole section through a transmission pair.

[0008] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the rotating shaft has a rotor on the outside of the first hole section, the rotor includes a magnet patch mounted on the outer surface of the rotating shaft, and the machine body has a stator that cooperates with the rotor.

[0009] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the retraction shaft is supported on the retraction shaft bearing seat by a plurality of back-to-back retraction shaft bearings.

[0010] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the front end of the machine body is provided with a front bearing housing, the rotating shaft is supported on the front bearing housing by the front bearing, the rear end of the machine body is provided with a rear bearing housing, the rotating shaft is supported on the rear bearing housing by the rear bearing, and at least one of the front bearing and the rear bearing includes a plurality of rotating shaft bearings mounted back to back.

[0011] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the retraction shaft assembly further includes a retraction shaft drive mechanism, the output end of which is connected to the retraction shaft bearing seat, the retraction shaft drive mechanism is disposed at the rear of the machine body, and the machine body is provided with a rear end cover on the rear side of the retraction shaft drive mechanism.

[0012] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the retraction shaft drive mechanism includes a drive motor and a ball screw, the input end of the ball screw is connected to the output end of the drive motor, and the output end of the ball screw is connected to the retraction shaft bearing housing.

[0013] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the output end of the drive motor is provided with a harmonic reducer.

[0014] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the drive motor is equipped with an encoder.

[0015] In a second aspect, a welding machine includes a friction stir welding spindle as described in any implementation of the first aspect.

[0016] One of the above technical solutions has at least one of the following advantages or beneficial effects: In the technical solution of the present invention, the stirring shoulder at the end of the rotating shaft and the stirring pin at the end of the retraction shaft are components that directly contact the workpiece in friction stir welding. During operation, they are driven to rotate by the rotation. When the stirring shoulder rotates at high speed, it generates frictional heat with the workpiece to be welded, causing strong plastic deformation of the workpiece material near the stirring shoulder. At the same time, the stirring pin also rotates at high speed under the action of the transmission pair, also generating frictional heat with the workpiece material to be welded, accelerating the plastic deformation of the workpiece material. The friction stir welding spindle drives the stirring shoulder and the stirring pin to move slowly along the joint of the workpiece to be welded, thus forming a weld at the joint of the two workpieces. After welding is completed, the stirring pin moves upward and is pulled out from the weld of the workpiece to be welded. At this time, the material that is still in the process of plastic deformation will fill the hole formed by the pulling out of the stirring pin, thus avoiding the generation of keyholes.

[0017] In the technical solution of the present invention, the retraction shaft assembly, which serves as the support structure for the stirring pin, adopts a retraction shaft bearing seat fitted on the outside of the retraction shaft. That is, the retraction shaft extends into the retraction shaft bearing seat and is supported by the retraction shaft bearing seat. This structural form allows the retraction shaft assembly to use a larger size retraction shaft bearing, thereby giving the retraction shaft high axial rigidity and improving welding quality and welding speed.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of an embodiment of the friction stir welding spindle of the present invention. Detailed Implementation

[0020] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0021] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the purpose of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0022] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0023] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0024] in, Figure 1 The reference direction coordinate system of this invention is given below, in conjunction with... Figure 1 The directions shown illustrate embodiments of the present invention.

[0025] See Figure 1 An embodiment of the present invention provides a friction stir welding spindle, including a body 100, a rotating shaft 200, and a retraction shaft assembly. The body 100 is fixed to a machine tool during use, serving to support the entire friction stir welding spindle. The rotating shaft 200 is mounted to the body 100 via a rotating shaft bearing. The rotating shaft 200 has an internal shaft core hole, and its end has a stirring shoulder 201, which rotates under the drive of the rotating shaft 200. The retraction shaft assembly includes a retraction shaft 301 and a retraction shaft bearing seat 302. The retraction shaft 301 is disposed in the inner hole of the shaft core. The retraction shaft 301 and the rotating shaft 200 are connected by a transmission pair 303, so that the retraction shaft 301 can rotate synchronously with the rotating shaft 200 and float axially. The end of the retraction shaft 301 is provided with a stirring needle 304 that can extend outward from the stirring shoulder 201. The stirring needle 304 can move synchronously with the retraction shaft 301. The retraction shaft bearing seat 302 is disposed in the inner hole of the shaft core and is clearance-fitted with the inner hole of the shaft core. The retraction shaft 301 extends into the retraction shaft bearing seat 302 and is supported in the retraction shaft bearing seat 302 by the retraction shaft bearing 305.

[0026] Combination Figure 1In the technical solution of this invention, the stirring shoulder 201 at the end of the rotating shaft 200 and the stirring pin 304 at the end of the retraction shaft 301 are the components that directly contact the workpiece in friction stir welding. During operation, they are driven to rotate by the rotation. When the stirring shoulder 201 rotates at high speed, it generates frictional heat with the workpiece to be welded, causing strong plastic deformation of the workpiece material near the stirring shoulder 201. At the same time, the stirring pin 304 also rotates at high speed under the action of the transmission pair 303, also generating frictional heat with the workpiece material to be welded, accelerating the plastic deformation of the workpiece material. The friction stir welding spindle drives the stirring shoulder 201 and the stirring pin 304 to slowly move along the joint of the workpiece to be welded, thus forming a weld at the joint of the two workpieces. After welding is completed, the stirring pin 304 moves upward and is pulled out from the weld of the workpiece to be welded. At this time, the material that is still in the process of plastic deformation will fill the hole formed by the pulling out of the stirring pin 304, thus avoiding the generation of keyholes.

[0027] In the technical solution of the present invention, the retraction shaft assembly, which serves as the support structure for the stirring needle, employs a retraction shaft bearing seat 302 fitted on the outside of the retraction shaft 301. That is, the retraction shaft 301 extends into the retraction shaft bearing seat 302 and is supported by the retraction shaft bearing 305. This structural form allows the retraction shaft assembly to use a larger size retraction shaft bearing 305, thereby giving the retraction shaft 301 high axial rigidity and improving welding quality and welding speed.

[0028] The agitator shoulder 201 can be directly or indirectly mounted on the rotating shaft 200, for example, in... Figure 1 In the embodiment shown, the stirring shoulder 201 is mounted on the rotating shaft 200 via the handle 202 and rotates under the drive of the rotating shaft 200.

[0029] Among them, the transmission pair 303 can adopt a keyway fit that extends along the axial direction or a non-circular cross-section fit, etc.

[0030] In some embodiments, see Figure 1 The inner hole of the shaft core is a stepped hole, comprising a first hole section 203 and a second hole section 204 along the axial direction. The inner diameter of the first hole section 203 is larger than that of the second hole section 204. A retraction shaft bearing seat 302 is disposed in the first hole section 203, thereby allowing for a larger radial dimension of the retraction shaft bearing seat 302. This enables the retraction shaft assembly to use a larger-sized retraction shaft bearing 305, resulting in high axial rigidity of the retraction shaft 301 and further improving welding quality and speed. The retraction shaft 301 and the rotating shaft 200 are engaged in the second hole section 204 via a transmission pair 303, transmitting rotational torque. Simultaneously, the radial engagement between the retraction shaft 301 and the rotating shaft 200 in the second hole section 204 provides high radial rigidity for the retraction shaft 301.

[0031] Further, see Figure 1 The rotating shaft 200 has a rotor 401 on the outer side of the first hole section 203. The rotor 401 includes magnets that are patch-mounted on the outer surface of the rotating shaft 200. The machine body 100 has a stator 402 that mates with the rotor 401. In this embodiment, the stator 402 and the rotor 401 work together to provide the driving force for rotating the rotating shaft 200 and the retraction shaft 301. By using a patch-mounted rotor 401 structure, the radial dimension of the rotor 401 can be compressed as much as possible while still meeting the driving force requirements. This further provides radial space for the retraction shaft bearing seat 302 inside the rotating shaft 200, allowing the retraction shaft assembly to use a larger retraction shaft bearing 305. This results in higher axial rigidity of the retraction shaft 301, further improving welding quality and welding speed.

[0032] In some embodiments, see Figure 1 The retraction shaft 301 is supported on the retraction shaft bearing seat 302 by multiple back-to-back retraction shaft bearings 305, which gives the retraction shaft 301 high axial rigidity.

[0033] In some embodiments, see Figure 1 The machine body 100 has a front bearing housing 101 at its front end, and the rotating shaft 200 is supported on the front bearing housing 101 by a front bearing 102. The front bearing 102 is pressed against the front bearing cover 103. The machine body 100 has a rear bearing housing 104 at its rear end, and the rotating shaft 200 is supported on the rear bearing housing 104 by a rear bearing 105. The rear end of the rotating shaft 200 is fitted into the inner ring of the rear bearing 105 and pressed against the rear bearing cover 106. The front end of the rotating shaft 200 is fitted into the inner ring of the front bearing 102 and pressed against the front bearing locking nut 107. The rotating shaft 200 can rotate under the support of the front bearing 102 and the rear bearing 105. At least one of the front bearing 102 and the rear bearing 105 includes multiple back-to-back mounted shaft bearings, giving the rotating shaft 200 high axial rigidity.

[0034] In some embodiments, see Figure 1 The retraction shaft assembly also includes a retraction shaft drive mechanism. The output end of the retraction shaft drive mechanism 500 is connected to the retraction shaft bearing housing 302. The retraction shaft drive mechanism 500 is located at the rear of the machine body 100, and the machine body 100 has a rear end cover on the rear side of the retraction shaft drive mechanism 500. In this embodiment, the retraction shaft drive mechanism 500 is used to drive the rotary shaft 200 to retract or extend outward. By embedding the retraction shaft drive mechanism 500 inside the main shaft, the axial dimension of the main shaft can be greatly shortened, resulting in a more compact structure.

[0035] Further, see Figure 1The retraction shaft drive mechanism 500 includes a drive motor 501 and a ball screw 502. The input end of the ball screw 502 is connected to the output end of the drive motor 501, and the output end of the ball screw 502 is connected to the retraction shaft bearing housing 302. Compared with other ball screws or drive mechanisms, the ball screw 502 has higher axial stiffness, giving the retraction shaft 301 high axial stiffness.

[0036] In specific operation, the friction stir welding spindle of this invention moves to a specific position until the stirring shoulder 201 presses against the workpiece to be welded. After the stirring shoulder 201 presses against the workpiece, the retraction shaft drive mechanism 500 issues commands, causing the input end of the ball screw 502 to rotate and the output end of the ball screw 502 to move downward linearly, causing the retraction shaft bearing seat 302 to move downward linearly, and causing the retraction shaft 301 to move downward linearly, so that the stirring needle 304 moves downward and inserts into the joint of the workpiece to be welded. Because the retraction shaft 301 and the rotating shaft 200 are connected together by a transmission pair 303, the retraction shaft 301 can move up and down linearly independently within the rotating shaft 200, while in the circumferential direction, under the action of the transmission pair 303, the retraction shaft 301 and the rotating shaft 200 rotate synchronously.

[0037] When the stirring shoulder 201 presses against the workpiece to be welded and the stirring pin 304 is inserted into the joint of the workpiece to be welded, the motor drives the rotating shaft 200 to rotate. The rotating shaft 200 drives the stirring shoulder 201 to rotate. Because the stirring shoulder 201 presses against the workpiece, the high-speed rotation of the stirring shoulder 201 generates frictional heat with the workpiece to be welded, causing strong plastic deformation of the workpiece material near the stirring shoulder 201. At the same time, the stirring pin 304 also rotates at high speed under the action of the connecting pair, also generating frictional heat with the workpiece material to be welded, accelerating the plastic deformation of the workpiece material. Simultaneously, under the action of the external mechanism, the friction stir welding spindle drives the stirring shoulder 201 and the stirring pin 304 to slowly move along the joint of the workpiece to be welded, thus forming a weld at the joint of the two workpieces.

[0038] After welding is completed, the motor stops, the rotating shaft 200 stops rotating, the retraction shaft 301 stops rotating, and the retraction shaft drive mechanism 500 issues a command to drive the input end of the roller screw 502 to rotate in the opposite direction and the output end of the roller screw 502 to move upward linearly, which drives the retraction shaft bearing seat 302 to move upward linearly, and drives the retraction shaft 301 to move upward linearly, so that the stirring needle 304 moves upward and is pulled out from the weld of the welded workpiece. At this time, the material that is still in plastic deformation will fill the hole formed by the extraction of the stirring needle 304, thus avoiding the formation of keyholes.

[0039] In some embodiments, in order to improve the control accuracy of the retraction shaft 301, a harmonic reducer is provided at the output end of the drive motor 501.

[0040] Furthermore, the drive motor 501 is equipped with an encoder. By using the encoder to form a closed-loop control, the number of rotations can be accurately memorized, and the number of rotations and rotation speed of the ball screw 502 can be precisely controlled, thereby precisely controlling the extension distance and extension speed of the retraction shaft 301.

[0041] Embodiments of the present invention also provide a welding machine, including the friction stir welding spindle of any of the above embodiments.

[0042] In the description of this specification, references to terms such as "example," "embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A friction stir welding spindle, characterized in that, The device includes a body, a rotating shaft, and a return shaft assembly. The rotating shaft is mounted to the body via a rotating shaft bearing. The rotating shaft has an internal core hole and a stirring shoulder at its end. The return shaft assembly includes a return shaft and a return shaft bearing housing. The return shaft is disposed within the core hole. The return shaft and the rotating shaft are coupled via a transmission pair, enabling the return shaft to rotate synchronously with the rotating shaft and float axially. The end of the return shaft has a stirring arm that extends outward from the stirring shoulder. The needle has a retraction shaft bearing seat disposed in the inner hole of the shaft core and in clearance fit with the inner hole of the shaft core. The retraction shaft bearing seat is fitted on the outside of the retraction shaft. The retraction shaft extends into the retraction shaft bearing seat and is supported by the retraction shaft bearing seat through the retraction shaft bearing. The inner hole of the shaft core includes a first hole section and a second hole section along the axial direction. The inner diameter of the first hole section is larger than the inner diameter of the second hole section. The retraction shaft bearing seat is disposed in the first hole section. The retraction shaft and the rotating shaft are engaged in the second hole section through a transmission pair.

2. The friction stir welding spindle according to claim 1, characterized in that, The rotating shaft has a rotor on the outside of the first hole section. The rotor includes magnets that are patched and mounted on the outer surface of the rotating shaft. The machine body has a stator that cooperates with the rotor.

3. The friction stir welding spindle according to claim 1, characterized in that, The retraction shaft is supported on the retraction shaft bearing seat by a plurality of back-to-back retraction shaft bearings.

4. The friction stir welding spindle according to claim 1, characterized in that, The front end of the machine body is provided with a front bearing housing, and the rotating shaft is supported on the front bearing housing by the front bearing. The rear end of the machine body is provided with a rear bearing housing, and the rotating shaft is supported on the rear bearing housing by the rear bearing. At least one of the front bearing and the rear bearing includes a plurality of rotating shaft bearings mounted back to back.

5. The friction stir welding spindle according to claim 1, characterized in that, The retraction shaft assembly also includes a retraction shaft drive mechanism. The output end of the retraction shaft drive mechanism is connected to the retraction shaft bearing seat. The retraction shaft drive mechanism is located at the rear of the machine body, and the machine body has a rear end cover on the rear side of the retraction shaft drive mechanism.

6. The friction stir welding spindle according to claim 5, characterized in that, The retraction shaft drive mechanism includes a drive motor and a ball screw. The input end of the ball screw is connected to the output end of the drive motor, and the output end of the ball screw is connected to the retraction shaft bearing housing.

7. The friction stir welding spindle according to claim 6, characterized in that, The output end of the drive motor is equipped with a harmonic reducer.

8. The friction stir welding spindle according to claim 7, characterized in that, The drive motor is equipped with an encoder.

9. A welding machine, characterized in that, The spindle for friction stir welding includes any one of claims 1 to 8.

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