CN107097008B

CN107097008B - Welding clamping device

Info

Publication number: CN107097008B
Application number: CN201710501805.8A
Authority: CN
Inventors: 郭志强; 韩宪兵; 刘昌旭; 潘海明
Original assignee: SAIC Volkswagen Automotive Co Ltd
Current assignee: SAIC Volkswagen Automotive Co Ltd
Priority date: 2017-06-27
Filing date: 2017-06-27
Publication date: 2023-05-12
Anticipated expiration: 2037-06-27
Also published as: CN107097008A

Abstract

The invention relates to a welding clamping device, which comprises a clamping unit, a clamping arm unit, a constant clamping force control unit and a main pin shaft; the clamping arm unit comprises a second transmission arm and a first transmission arm; the clamping unit is rotationally connected through a main pin shaft, the second transmission arm is fixedly connected with the proximal end of the clamping unit, and the first transmission arm is fixedly connected with the distal end of the clamping unit; the constant clamping force control unit is provided with a body and a telescopic rod, the tail end of the telescopic rod is rotationally connected with the first transmission arm, and the body is rotationally connected with the second transmission arm; limiting blocks are arranged on two sides of the main pin shaft and used for limiting the opening angle of the clamping device in an unclamped state. The clamping process and the loosening process of the constant clamping force control unit are divided into two steps, and the clamping unit is positioned by the workpiece to be clamped and the limiting block when the second step of movement is completed, so that the constant clamping force control unit is ingenious in design and high in accuracy of clamping position.

Description

Welding clamping device

Technical Field

The invention relates to the field of automatic welding of automobiles, in particular to a clamping device for automatic laser welding of automobiles.

Background

In the field of automatic welding of automobiles, the welding quality of laser welding has extremely high matching requirement on parts, stable clamping between workpieces plays a very important role on the welding quality during welding, how to stably clamp the workpieces and eliminate matching gaps is a difficult point of door frame laser fusion welding during welding, the clamping mode of the current production line can only manually arrange clamping points at the front part of a light source focus of a laser welding manipulator, and the moving mode during welding at the clamping point area in the welding process of the manipulator is hard sliding, so that the welding quality is not ideal.

The complete production flow of a car is shown in figure 1, wherein the manufacturing link of 'pre-batch license whole car' 8 weeks before formally starting production is a key link before starting production of a new car type, and is an important bridge from product design to production. At the same time, in the "pre-batch approval whole vehicle" stage, a plurality of important vehicles need to be delivered to important clients, such as: 10 ten thousand kilometers of road endurance test vehicles, collision vehicles, congatan comparison vehicles, exhibition vehicles, rigidity test vehicles and strength test vehicles for dynamic comprehensive tests, pilot test driving test vehicles, external verification vehicles and the like. The quality of stamping parts in the stage of 'pre-batch approval whole vehicle' is low, the delivery period of the clamp is short, the configuration of the clamp is low, the production quantity of the vehicle body is more, and the laser welding station is a bottleneck station of the whole stage of 'pre-batch approval whole vehicle' (the working procedures of roof brazing, side wall water falling groove brazing, rear cover outer plate brazing, side wall door opening fusion welding and the like are required to be completed at the station).

At present, the side wall door frames of most of domestic automobiles are subjected to resistance spot welding, and only a few manufacturers adopt laser welding. For the laser fusion welding process of the inner and outer coamings, the process is generally as follows: (1) the manual trolley and the whole vehicle body enter a laser room; (2) manually descending the vehicle body, falling into a positioning unit on a flexible positioning platform, and positioning and clamping the vehicle body (3) welding the vehicle body by a laser fusion welding robot; (4) opening a clamping and positioning unit on the car body after the welding of the single-side wall plate is completed, manually lifting the car body, and pulling the car body with the car body out of the laser room; (5) after turning the car body 180 degrees, pushing the car body into a laser room; (6) manually descending the vehicle body, falling into a positioning unit on the flexible positioning platform again, and positioning and clamping the vehicle body; (7) the laser fusion welding robot welds the car body again; (8) and opening the clamping and positioning unit on the vehicle body after welding, manually lifting the trolley to bear the vehicle body, and pulling out of the laser room to finish welding.

Currently, in the prior art, clamping and welding can be completed by installing a clamping device on a laser welding manipulator. But the device can solve a large amount of C type clamp dismouting problems to a certain extent, but this product except that the price is expensive, delivery period is long, maintenance response is untimely, on-the-spot service is kept up with a lot of adverse circumstances such as not, and there are a lot of shortages in the product itself, like:

(1) the product is a single-point hard slip clamp before the focus of a light source, and the problem of matching gaps between metal plates at the starting point of laser welding cannot be solved;

(2) the problem that the robot is overlarge in load and the alarm stops line can not be solved due to the curvature self-adaptive compensation function of the surface of the side wall outer plate;

(3) if the Y-direction deviation of the side coaming is large, the batch production site can only stop the line and reprogram the side coaming to solve the clamping problem, otherwise, the robot stops working;

(4) the robot has no output device with constant clamping force, if welding slag is accumulated, the robot can give an alarm and stop running in the running process, and the robot needs to stop production to perform manual cleaning;

(5) the device has no output force adjustable device and no visual force output device;

it is known that the quality of laser welding requires extremely high matching clearance for sheet metal, the matching clearance between the steel plates should be kept between 0.1-0.3mm (0.2 mm is optimal), and a range below which severe welding spatter will occur, while a range above which a weld joint will be unstable and the quality of the laser weld joint will be unacceptable.

The clamping mode of the traditional C-shaped clamp can be adopted in the prior art. After the whole car body enters a laser room to fall, manual C-shaped clamp clamping treatment is needed for each sample car for approximately 100 minutes, time and labor are consumed, and other times such as car body in-out, car body positioning, 180-degree rotation of the car body, laser welding and the like are not included. The actual laser fusion welding process can be completed within about 10 minutes, and the advantages of high speed and high efficiency are dulled and discolored due to the traditional clamping mode.

It is an urgent task to accomplish the laser welding process with high quality and efficiency through innovation of the clamping technique for welded parts in the "pre-mass-licensed whole vehicle" stage.

Disclosure of Invention

The invention aims to solve the problem of matching gaps of metal plates at the starting point of laser welding and ensure the gaps of welding seams at the focal point of a light source, two points are equidistantly arranged in front of and behind the focal point of the light source to clamp, and meanwhile, the hard sliding of the clamping head is changed into rolling displacement of a roller, so that the requirement of matching gaps at the starting welding seams is ensured, and the sliding is changed into rolling to reduce the friction and abrasion of the welding surface, thereby improving the welding quality.

The invention adopts the following technical scheme:

a welding clamping device comprises a clamping unit, a clamping arm unit, a constant clamping force control unit 5 and a main pin shaft 7; the clamping arm unit comprises a second transmission arm and a first transmission arm; the clamping unit is rotationally connected through a main pin shaft 7, the second transmission arm is fixedly connected with the proximal end of the clamping unit, and the first transmission arm is fixedly connected with the distal end of the clamping unit; the constant clamping force control unit 5 is provided with a body and a telescopic rod, the tail end of the telescopic rod is rotationally connected with the first transmission arm, and the body is rotationally connected with the second transmission arm; limiting blocks are arranged on two sides of the main pin shaft 7 and used for limiting the opening angle of the clamping device in an unclamped state.

Further, the arm clamping unit 3 comprises a second transmission arm rotating block 3.2, a first transmission arm rotating block 3.1 and an arm adjusting piece 3.3; the first transmission arm and the second transmission arm rotating blocks 3.2 and 3.1 are hinged through a main pin shaft 7; the force arm adjusting piece 3.3 is provided with scales, and each scale value corresponds to the corresponding clamping force one by one; by adjusting the length of the arm adjustment member 3.3, an adapted clamping force can be selected.

Further, the arm of force regulating piece 3.3 has adjusting nut and two-way reverse screw thread lead screw structure.

Still further, still include connecting element 4, connecting element 4 is with invariable clamp force control unit 5, arm lock unit fixed connection respectively.

Still further still, still include space gesture balancing unit 6, space gesture balancing unit 6 has extension spring 6.4, extension spring both ends are connected with second transmission arm, first transmission arm respectively, and the extension spring keeps tensile state.

Further, the constant clamping force control unit 5 includes a cylinder and a pressure reducing valve.

Further, the clamping unit is a rolling clamping unit 1, the plane where the workpiece to be clamped is located is an XOY plane, and the direction perpendicular to the plane is the Z direction; the rolling clamping unit 1 is provided with at least two groups of rollers for clamping each other, and the linear speed direction of the rolling of the rollers is along the Y direction.

Further, the device also comprises a curvature compensation unit 2, wherein the curvature compensation unit 2 comprises a swinging block 2.1, the rolling clamping unit 1 is fixed on the swinging block 2.1, and the swinging axis of the swinging block 2.1 is arranged along the X direction; the swinging block 2.1 is subjected to the action of clamping the workpiece and can swing along the swinging axis in a small amplitude.

A working method of a welding clamping device,

and (3) clamping: the telescopic rod is ejected out to drive the first transmission arm to rotate around the main pin shaft 7 in a first direction, the first transmission arm props against the clamped workpiece, and the first transmission arm stops; the telescopic rod is continuously ejected, and under the positioning action of the clamped workpiece, the body of the constant clamping force control unit 5 drives the second transmission arm to rotate towards the second direction, and the second transmission arm props against the clamped workpiece;

the loosening process comprises the following steps: the telescopic rod is contracted, and the first transmission arm rotates along the second direction under the drive of the body of the constant clamping force control unit 5 until the first transmission arm abuts against the limiting block, and the first transmission arm stops; the telescopic rod continues to shrink, the second transmission arm is driven to rotate around the main pin shaft 7 along the first direction until the telescopic rod is shrunk and stopped, and the second transmission arm is stopped; wherein the first direction and the second direction are two opposite directions.

The invention has the beneficial effects that:

1) The clamping process and the loosening process of the constant clamping force control unit are divided into two steps, and the clamping unit is positioned by the clamped workpiece and the limiting block when the second step of movement is completed, so that the design is ingenious, and the accuracy of the clamping position is high;

2) The arm clamping unit is provided with an arm adjusting piece, so that the arm is conveniently adjusted, and the corresponding clamping force is directly obtained through the arm adjustment;

3) The space posture adjusting unit provides pretension force for the upper and first transmission arms, and effectively prevents the device from rotating clockwise;

4) The rolling clamping unit is a final execution unit of the clamping device and directly acts on the workpiece to finish the clamping effect, so that the clamping effect is good and the flexibility is strong;

5) The curvature of the arc surface of the swinging block of the curvature compensation unit is different from that of the arc surface of the swinging limiting block, the curvature of the swinging block is smaller than that of the arc surface of the swinging limiting block, and the swinging block and the arc surface of the swinging limiting block are connected together through a pin. When the curvature of the welding surface changes, the inner front roller and the outer front roller and the inner rear roller are slightly swung along with the constraint of the mechanical swinging device, so that the curvature self-adaptive double-point clamping of the front and the rear of the light source focus is realized, and therefore, the workpiece to be welded with uneven surface is always in a clamping state, the clamping effect is good, and the adaptability is strong.

6) The welding and clamping device is particularly suitable for welding and clamping procedures of automobile side coamings.

7) The output shaft of one driving part is used for simultaneously controlling the clamping and the opening of two clamping parts, so that the clamping structure is simple, and the whole clamping device is convenient and reliable to operate.

Drawings

FIG. 1 is a schematic diagram of a traffic flow.

Fig. 2 is a schematic diagram of the rolling clamping device for welding according to the present invention.

Fig. 3 is a schematic view showing a state in which a rolling clamping device for welding clamps a side wall plate of an automobile according to an embodiment of the present invention.

Fig. 4 is a schematic perspective view of a rolling clamping device for welding in an embodiment of the invention.

Fig. 5 is an exploded view of a rolling clamping unit in an embodiment of the present invention.

Fig. 6 is an assembly view of the rolling clamping unit of fig. 5.

Fig. 7 is a structural exploded view of a curvature compensation unit in an embodiment of the present invention.

Fig. 8 is a schematic top view of a curvature compensation unit according to an embodiment of the invention.

Fig. 9 is a configuration diagram of a clip arm unit in an embodiment of the present invention.

Fig. 10 is a front view of a rolling clamp device for welding in an embodiment of the present invention.

FIG. 11 is a schematic diagram of a visual clamping force output of a clamping arm unit in accordance with an embodiment of the present invention.

Fig. 12 is an exploded view of a structure of a connection unit in an embodiment of the present invention.

FIG. 13 is a schematic view illustrating the installation of the stopper according to an embodiment of the present invention.

Fig. 14 is a configuration diagram of a spatial posture balancing unit in an embodiment of the present invention.

Fig. 15 is a schematic view of a cylinder.

Fig. 16 is a schematic view showing an opened state of the rolling clamping device for welding in an embodiment of the present invention.

Fig. 17 is a schematic view showing a state of clamping by the rolling clamping device for welding in an embodiment of the present invention.

Fig. 18 is a schematic diagram of the operation of the welding plane adaptation.

Fig. 19 is a pressure relief valve for constant clamping force control.

In the drawings, 1. Rolling clamping unit, 2. Curvature compensation unit, 3. Clamping force adjustment display unit, 4. Connection unit, 5. Constant clamping force control unit, 6. Spatial attitude balancing unit, 7. Main pin, 1.1. Wheel axle, 1.2. Copper pad, 1.3. Roller, 1.4. Copper sleeve, 1.5 clamp plate, 1.6. Socket head cap screw, 2.1 swing block, 2.2. Pin, 2.3. Swing stopper, 3.1. Lower arm rotating block, 3.2. Upper arm rotating block, 3.3. Arm adjusting piece, 3.4. Elbow joint connecting block, 3.5. Hinge lug connecting block, 4.1. Fixed block, 4.2. Center connecting block, 4.3. Spring connecting piece, 4.4 stopper, 6.1. Tension spring, 6.2. Tension spring screw, 6.3. Tension spring connecting block, 6.4. Upper arm tension spring, 6.5. Lower arm tension spring, 6.6. Tension screw.

Detailed Description

The invention will be further described with reference to the drawings and specific examples.

And combining the actual situation of a laser fusion welding station, integrating the designed clamp on the lens group through the mounting hole of the original finger pressing area, wherein the working situation is shown in figure 3. The overall structure of the door frame laser welding clamping device is shown in fig. 4, and in one embodiment of fig. 4, the door frame laser welding clamping device is composed of a rolling clamping unit 1, a curvature compensation unit 2, a clamping force adjustment display unit 3, a constant clamping force control unit 5, a spatial posture balancing unit 6, and a connection unit 4. The rolling clamping unit 1, the curvature compensation unit 2 and the clamping force adjustment display unit 3 rotate by taking a main pin shaft 7 (shown in fig. 4) as axes, the rolling clamping units 1 are distributed in a group in an axisymmetric mode, and the inner side wall plate and the outer side wall plate of the door frame are clamped tightly, so that the requirement that a matching gap between the inner side wall plate and the outer side wall plate is not larger than 0.2mm in laser welding is met. The clamping actions of the two groups of rolling clamping units 1 are controlled through a group of constant clamping force control units 5 of the clamping device, the clamping force adjusting display unit 5 not only can adjust the magnitude of the clamping force, but also can output visual clamping force, the space posture balancing unit 6 stably balances the ideal position of the whole set of device, and the curvature compensation unit 2 effectively compensates the part generating curvature change on the surface of a welded part in the welding process. The whole set of device is integrated on the laser welding lens group through two pins and two nails (not labeled in fig. 4) on the connecting unit 4, so that the random robot moves synchronously, and the function of the robot follow-up clamp is realized.

Design of key units:

1) Rolling clamping unit:

the rolling clamping unit 1 mainly comprises a wheel shaft 1.1, a copper pad 1.2, a roller 1.3, a copper sleeve 1.4 and a clamping plate 1.5, is a final execution unit of the clamping device, directly acts on a workpiece to complete the clamping effect, and is combined with fig. 5 and 6. The copper bush 1.4 is embedded in the central hole of each roller 1.3, meanwhile, the front and the rear of each roller 1.3 are respectively provided with a copper pad 1.2, and the wheel shaft 1.1 is sleeved in the inner holes of the copper bush 1.4 and the copper pad 1.2. In order to ensure that the wheel 1.3 does not rotate along with the wheel 1.3 when rolling, a section of arc-shaped groove (not marked in fig. 5 and 6) is formed in the wheel 1.1 along the circumferential direction, the swinging block 2.1 is provided with the clamping plate 1.5, the arc-shaped part of the clamping plate 1.5 is clamped in the arc-shaped groove matched with the clamping plate, the clamping plate 1.5 is fixed by the inner hexagon bolt 1.6 through the mounting hole of the clamping plate 1.5, the connection with the wheel 1.1 is realized, and the synchronous rotation of the wheel 1.1 and the wheel 1.3 is prevented.

2) Curvature compensation unit

As shown in fig. 7, the curvature compensation unit 2 is a mechanical swinging device composed of a swinging block 2.1, a swinging limiting block 2.3 and a pin 2.2. The curvature of the arc surfaces of the swing block 2.1 and the swing limiting block 2.3 are different, the curvature of the arc surface of the swing block 2.1 is smaller than that of the arc surface of the swing limiting block 2.3, and the pin 2.2 connects the swing block 2.1 and the swing limiting block 2.3 together through coaxial holes. The swing limiting block 2.3 is fixed on an external transmission mechanism through two pins and one pin at the upper part of the swing limiting block to obtain power. When the curvature of the welding surface changes, the rollers on the two sides of the inner and outer plates of the side wall can slightly swing along with the constraint of the mechanical swinging device, so that the curvature self-adaptive double-point clamping of the front and rear light source focuses is realized, and the inner and outer plates of the side wall are always in a clamping state, as shown in fig. 8.

3) Arm unit

The arm unit is divided into a first transmission arm and a second transmission arm, referring to fig. 9 and referring to fig. 10, the first transmission arm (a lower transmission arm in the illustration of fig. 9) is mainly composed of a rotating block 3.1, an arm adjusting piece 3.3 and an elbow joint connecting block 3.4, and the second transmission arm (an upper transmission arm in the illustration of fig. 9) is mainly composed of a rotating block 3.2, an arm adjusting piece 3.3 and a cylinder hinge ear connecting block 3.5; the first and second transmission arms form a transmission unit of the clamping device. All the motion units in the device are gathered on the unit, and are connected with the curvature compensation unit and the double-point rolling unit through two pins and one pin on the rotating block of the first transmission arm and the second transmission arm; the elbow joint connection block 3.4 and the hinge ear connection block 3.5 are respectively in rotary connection with the output shaft of an actuating element, which in this embodiment is a cylinder.

Wherein, the output shaft of the cylinder is connected with a cylinder hinge lug connecting block 3.5 of the second transmission arm at one end close to the cylinder body; and one end of the output shaft of the cylinder, which is far away from the cylinder body, is connected with the elbow joint connecting block 3.4 of the first transmission arm.

In the process of clamping the power arm, the output shaft of the air cylinder outputs outwards, the first transmission arm rotates towards the positive direction shown in fig. 10 under the drive of the output shaft of the air cylinder, when the roller 1 of the first transmission arm abuts against the supporting point on the lower side of the door side inner and outer plates, the first transmission arm stops rotating, but the output shaft of the air cylinder continues to output, at the moment, the whole air cylinder takes the supporting point on the lower side of the door side inner and outer plates as the center, the whole air cylinder rotates towards the reverse direction, the second transmission arm synchronously rotates in the reverse direction, when the roller of the second transmission arm abuts against the supporting point on the upper side of the door side inner and outer plates, the output shaft of the air cylinder stops outputting, the roller of the first transmission arm and the roller of the second transmission arm abut against the two sides of the clamped door side inner and outer plates, and then the mechanical arm laser welder starts welding.

Screw holes 3.6 are formed in the elbow joint connecting blocks 3.4 and are connected with screw rods 6.6 of the space posture balancing units, main shaft pins 3.7 are arranged on the elbow joint connecting blocks and are fixed on the connecting units through main shaft pins 3.7, and the elbow joint connecting blocks 3.4 are movably connected with one ends, far away from the cylinder body, of the cylinder output shafts through mounting holes 3.8 formed in the elbow joint connecting blocks.

In the opening process of the power arm, the output shaft of the air cylinder inputs back, the first transmission arm opens towards the reverse rotation direction shown in fig. 10 under the drive of the output shaft of the air cylinder, when the first transmission arm abuts against the limiting block 4.4, the first transmission arm stops rotating, the opening angle is determined, the output shaft of the air cylinder continues to input back, the whole air cylinder rotates towards the forward direction by taking the limiting block 4.4 as a supporting point, the second transmission arm synchronously rotates in the forward direction, when the output shaft of the air cylinder inputs back to the stopping position, the opening angle of the second transmission arm also stops, and then the mechanical arm laser welder returns to the original position.

With continued reference to fig. 9 in combination with fig. 11, the arm unit may also have a clamping force adjustment display function. The arm unit can be similar to a lever mechanism, one end of the arm unit is connected with the air cylinder, the other end of the arm unit is connected with the clamping unit, a force arm adjusting piece 3.9 can be arranged in the middle of the arm unit, and left-handed and right-handed threaded rods are respectively arranged at two ends of the arm adjusting piece 3.9. For example, a left-handed threaded rod is arranged at the connection part of the first rotating arm rotating block 3.1 and the second rotating arm rotating block 3.2 and the arm adjusting piece 3.9, a right-handed threaded rod is arranged at the connection part of the cylinder connecting block 3.5 and the elbow connecting block 3.4 and the arm adjusting piece 3.8, and threaded rods at two ends are respectively screwed into threaded holes corresponding to the arm adjusting piece 3.9. In this embodiment, the arm adjusting member 3.9 may be a telescopic sleeve, and by screwing the telescopic sleeve, both ends of the sleeve simultaneously extend or retract by the same length, so as to synchronously adjust the length of the power arm, and according to the lever force balance principle, further, the output clamping force of the driving arm may be changed. For a more visual and clear understanding of the clamping force, a facet may be milled into the threaded rod of the rotor 3.1 or/and the rotor 3.2, and an indication of the clamping force may be engraved into the facet, as shown in fig. 11, the magnitude of which is calculated based on the selected cylinder type or arm length. It will also be appreciated that a facet can also be milled into the threaded rod connecting the cylinder connection block 3.5 and the elbow connection block 3.4 to the arm adjustment member 3.9, on which facet an indication of the amount of clamping force is engraved, by means of which the required clamping force can be accurately displayed on site by means of simple adjustment and display means, in order to facilitate effective analysis and adjustment in process control, improving the welding quality. 4) A connection unit:

referring to fig. 12 in combination with fig. 13, the connection unit is mainly composed of a fixed block 4.1, a central connection block 4.2, a spring connection 4.3 and a kingpin 7. In order to ensure the relative position precision of the assembled units, the connection in the unit adopts a four-pin and two-pin (not labeled in fig. 12), thereby realizing the reliable connection between the unit and the inner part of the device and between the welding lens groups and the outer part of the device.

For the connection between the connection unit and the rolling clamping unit, to limit the opening angle of the clamping force adjusting display unit around the main pin shaft, a limiting block 4.4 may be disposed at a position corresponding to a certain opening angle of the first power arm or/and the second power arm in the groove area of the central connection block 4.2, and in this embodiment, the limiting block may be a bolt-like limiting block, and the specific position is shown in fig. 13. The length of the bolt leaving the central connecting block 4.2 is adjusted by the screw thread screwing of the limiting block, so that the opening angle of the power arm in the unclamped state of the clamping device can be indirectly adjusted and controlled.

5) Spatial attitude balancing unit:

referring to fig. 14, the spatial posture balancing unit is mainly composed of a tension spring connection block 6.3, a tension spring screw rod 6.2, a tension spring screw rod 6.6, a second tension spring 6.4 and a first tension spring 6.5. Two tension springs can be arranged in the unit to respectively balance the forces in the clockwise direction and the anticlockwise direction. The first end of the first tension spring is connected with the output end of the air cylinder, and the second end of the first tension spring is fixed with the connecting unit. In the process that the air cylinder extends out and the product to be welded is clamped, the whole clamping device can rotate anticlockwise along the main pin shaft by a certain angle due to the fact that the center of gravity is deviated (towards one side of the air cylinder), and the device is balanced and stable on the surface of a workpiece under the elastic action of the first tension spring and does not change the angle due to weight unbalance. The elastic force of the tension spring can be adjusted through the tension spring screw rod 6.2 or/and the tension spring screw rod 6.2, on one hand, the strength of the tension spring can be adjusted through the screwing of the tension spring screw rod and the screw thread of the connecting block, and on the other hand, the elastic force can be adjusted through changing tension springs with different lengths. The second tension spring has the same action principle and is mainly used for preventing the device from rotating clockwise. Because of the limitation of the space at the joint of the second power arm and the cylinder, a tension spring connecting block 6.3 is added on the hinge lug connecting block 3.5 of the second power arm for connecting the tension spring.

The weld plane adaptation function may be provided mainly by a clamping cylinder, as shown in fig. 15. According to the requirements of clamping force, the available space and the on-site selection of different air inlet pressure and cylinder types, in the embodiment, the SMC clamping cylinder with the stroke of 75mm can be selected.

The output shaft of the air cylinder 7 is connected with the connecting block of the clamping force adjusting display unit through the hinge lug end, as shown in fig. 16 and 17, and the air cylinder 7 provides a power source for the whole clamping device. The working principle is as follows: the air is introduced from the air inlet end 7.1, the air outlet end 7.2 is used for air outlet, the piston rod extends out, the first power arm acts firstly until the roller inside the automobile body contacts with the side wall inner plate, at the moment, the piston rod continues to extend out, and the second power arm acts until the roller outside the automobile body contacts with the side wall outer plate, so that clamping is completed. At this time, the cylinder does not run through the full stroke, and a partial stroke is required to be reserved, in this embodiment, a 10mm stroke is reserved for holding the clamping force and adapting to the Y-directional deviation of the welding plane, as shown in fig. 18. The ideal position of the side wall plate is the position of "position 2" in the figure, but if there is a deviation, it may be in the position of "position 1" or "position 3". No matter how the size fluctuates and fluctuates between the position 1 and the position 3, according to the preset travel set by the air cylinder, after the inner roller is contacted with the side wall inner plate, the piston rod continues to extend to drive the upper arm to act until the outer roller is contacted with the side wall outer plate, and both sides of the welding plane can be clamped, so that the self-adaptive function requirement of the welding plane is met.

Fig. 19 is a pressure reducing valve for constant clamping force control, in which the accuracy of the clamping force can be maintained by automatically reducing the pressure of air supplied from the outside above a predetermined range through the use of the pressure reducing valve in the cylinder air path in the present embodiment.

The foregoing is a preferred embodiment of the present invention, and various changes and modifications may be made therein by those skilled in the art without departing from the general inventive concept, and such changes and modifications should be considered as falling within the scope of the claimed invention.

Claims

1. A welding clamping device, characterized in that:

comprises a clamping unit, a clamping arm unit, a constant clamping force control unit (5) and a main pin shaft (7);

the clamping arm unit comprises a second transmission arm and a first transmission arm;

the clamping unit is rotationally connected through a main pin shaft (7), the second transmission arm is fixedly connected with the proximal end of the clamping unit, and the first transmission arm is fixedly connected with the distal end of the clamping unit; the constant clamping force control unit (5) is provided with a body and a telescopic rod, the tail end of the telescopic rod is rotationally connected with the first transmission arm, and the body is rotationally connected with the second transmission arm;

limiting blocks are arranged on two sides of the main pin shaft (7) and used for limiting the opening angle of the clamping device in an unclamped state;

the arm clamping unit (3) comprises a second transmission arm rotating block (3.2), a first transmission arm rotating block (3.1) and an arm of force adjusting piece (3.3); the first transmission arm rotating block (3.1) and the second transmission arm rotating block (3.2) are hinged through a main pin shaft (7); the force arm adjusting piece (3.3) is provided with scales, and each scale value corresponds to the corresponding clamping force one by one; by adjusting the length of the arm adjustment element (3.3), an adaptive clamping force can be selected.

2. The welding clamping device of claim 1, wherein: the arm of force regulating part (3.3) has adjusting nut and two-way back-screw thread lead screw structure.

3. The welding clamping device of claim 2, wherein: the clamping device further comprises a connecting unit (4), wherein the connecting unit (4) is fixedly connected with the constant clamping force control unit (5) and the clamping arm unit respectively.

4. A welding clamping device as defined in claim 3, wherein: the device further comprises a space posture balancing unit (6), the space posture balancing unit (6) is provided with a tension spring (6.4), two ends of the tension spring are respectively connected with the second transmission arm and the first transmission arm, and the tension spring is kept in a stretching state.

5. The welding clamping device of claim 1, wherein: the constant clamping force control unit (5) comprises a cylinder and a pressure reducing valve.

6. The welding clamping device of claim 1, wherein: the clamping unit is a rolling clamping unit (1), the plane where the workpiece to be clamped is located is an XOY plane, and the direction perpendicular to the plane is the Z direction; the rolling clamping unit (1) is provided with at least two groups of rollers used for clamping each other, and the linear speed direction of the rolling of the rollers is along the Y direction.

7. The welding clamping device of claim 6, wherein: the rolling clamping device further comprises a curvature compensation unit (2), wherein the curvature compensation unit (2) comprises a swinging block (2.1), the rolling clamping unit (1) is fixed on the swinging block (2.1), and the swinging axis of the swinging block (2.1) is arranged along the X direction; the swinging block (2.1) can swing along the swinging axis in a small amplitude in an adaptive manner under the action of clamping the workpiece.

8. A method of operating a welding clamping device as claimed in claim 1, wherein:

and (3) clamping: the telescopic rod is ejected out to drive the first transmission arm to rotate around the main pin shaft (7) in a first direction, the first transmission arm props against the clamped workpiece, and the first transmission arm stops; the telescopic rod is continuously ejected, and under the positioning action of the clamped workpiece, the body of the constant clamping force control unit (5) drives the second transmission arm to rotate towards the second direction, and the second transmission arm props against the clamped workpiece;

the loosening process comprises the following steps: the telescopic rod is contracted, and the first transmission arm rotates along the second direction under the drive of the body of the constant clamping force control unit (5) until the first transmission arm abuts against the limiting block, and the first transmission arm stops; the telescopic rod continues to shrink, the second transmission arm is driven to rotate around the main pin shaft (7) along the first direction until the telescopic rod is shrunk and stopped, and the second transmission arm is stopped; wherein the first direction and the second direction are two opposite directions.