CN100520343C - Cross point welding sample multidirectional fatigue loading fixture - Google Patents

Abstract

The invention relates to a cross-shaped spot welding sample multi-directional fatigue loading clamp device, which belongs to the technical field of machinery and automobile manufacturing. It mainly includes a lower clamping body (9) and an upper clamping body (8). In the lower clamping body (9), the upper surface of the base (1) is provided with a trapezoidal block (5) capable of sliding along it. Wedge-shaped clamping blocks (2) are arranged on both sides of the trapezoidal block (5), and the wedge-shaped clamping block 2 can slide under the promotion of the slope of the trapezoidal block 5. A rectangular groove is formed between the other surface of the wedge-shaped clamping block 2 and the base 1 for placing spot welding samples. The above-mentioned parts of the lower clamping body 9 are the same as the upper clamping body 8, the difference is that the locking disc 7 of the lower clamping body 9 is located on the lower surface of the base 1, and the locking disc 7 of the upper clamping body 8 is located on the upper surface of the base 1 , The locking disc 7 is provided with a loading hole. The invention enables spot welding samples to simultaneously bear tensile and shearing cyclic loads in different directions, maintains the correct position of the samples in the clamping body, and realizes the clamping of the samples.

Description

A cross-shaped spot welding specimen multi-directional fatigue loading fixture device

technical field

The invention relates to a multi-directional fatigue loading fixture device for a cross-shaped spot welding sample, which is used for positioning and clamping a spot welding fatigue sample in a cross-shaped tension-shear multi-directional fatigue loading test, and belongs to the machinery and automobile manufacturing technology field.

technical background

Resistance spot welding has the advantages of low cost, high efficiency, and simple operation. It is very suitable for mass production and has been widely used in modern industry, especially in the automobile industry. As modern automobiles increasingly adopt thinner high-strength steel plates in the direction of high strength and reliability, light weight, and fuel saving, the stiffness of spot welded joints decreases due to the thinning of the plates, making them fatigue Reduced strength. Therefore, technicians should regard the fatigue performance of solder joints as an important parameter of automobile safety and reliability in the design, and it is necessary to evaluate the fatigue performance of spot welding samples under uniaxial or multidirectional cyclic loading.

At present, many domestic manufacturers have begun to consider the fatigue strength of spot welding in the design and carry out fatigue tests. In fatigue tests, uniaxial (shear) cyclic loading is often used for spot welded samples. In reality, in addition to shear loads, most solder joints inevitably bear cyclic tensile loads perpendicular to the plane of the solder joints, which makes the force situation of spot welded joints more complicated than when bearing uniaxial loads , that is, the solder joint is often in a multidirectional stress state. Therefore, uniaxial loading is oversimplified, and the multidirectional loading fatigue performance of solder joints needs to be considered. At present, domestic research on the fatigue strength and life prediction of spot welded specimens under multi-directional cyclic loading has not yet been carried out. Therefore, it is of great practical significance to conduct fatigue test research on spot welded joints under multi-directional cyclic loading. The necessary fixtures for fatigue testing of spot welded joints under multi-directional cyclic loading have not yet appeared in China. This invention provides a positioning clamp for such research.

Contents of the invention

The purpose of the present invention is to provide a positioning and clamping device for a cross-shaped spot welding sample, which ensures that the spot welding sample can bear the tension-shear cycle load in different directions at the same time, keeps the sample in the correct position in the clamping body, and realizes Clamping of the specimen.

In order to achieve the above object, the present invention adopts the following technical solutions. The present invention mainly includes two lower clamping bodies 9 and upper clamping bodies 8 which are similar in structure and independent of each other. Wherein, the lower clamping body 9 mainly includes a base 1, a trapezoidal block 5, a wedge-shaped clamping block 2, and a locking plate 7. A groove is arranged on the upper surface of the base 1, and the groove is symmetrical with respect to the center line of the upper surface. The trapezoidal block 5 and the wedge-shaped clamping block 2 are arranged in the groove, the centerline of the trapezoidal block 5 coincides with the centerline of the upper surface of the base 1, and is arranged on the side of the base 1 along the axis direction of the trapezoidal block 5 There is a drive screw 4, and the drive screw 4 cooperates with the bottom surface of the trapezoidal block 5, and the trapezoidal block 5 can slide along the center line of the upper surface of the base 1 under the push of the drive screw 4. Both sides of the slope of the trapezoidal block 5 are symmetrically provided with wedge-shaped clamping blocks 2, the slope of the wedge-shaped clamping block 2 can be matched with the slope of the trapezoidal block 5, and the wedge-shaped clamping block 2 can be pushed by the slope of the trapezoidal block 5 Sliding along the direction perpendicular to the center line of the trapezoidal block 5, a rectangular groove is formed between the side of the wedge-shaped clamping block 2 away from the trapezoidal block 5 and the base 1 for placing spot welding samples. The structure of the lower clamping body 9 is the same as that of the upper clamping body 8 , except that the structure is located on the lower surface of the upper clamping body 8 . Both the lower surface of the lower clamping body 9 and the upper surface of the upper clamping body 8 are provided with a locking disc 7, and the locking disc 7 is provided with a loading hole.

The locking disc 7 of the lower clamping body 9 is located on the lower surface of the base 1 and is perpendicular to the center line of the trapezoidal block 5, and the locking disc 7 of the upper clamping body 8 is located on the upper surface of the base 1 and is perpendicular to the centerline of the trapezoidal block 5. The centerlines are coincident, and the locking disc 7 is provided with a loading hole.

A positioning block 3 is provided on the upper surface of the base 1 of the lower clamping body 9 and on the side close to the rectangular groove.

The lock plate 7 is fan-shaped, and there are five sets of loading holes at 30°, 45°, 60°, 75°, and 90° to the base 1 along the circumferential direction. After the spot welding sample is clamped, , the loading holes of the upper and lower locking discs are distributed on a circle, and the center of the circle is the center of the solder joint of the sample.

The groove on the base 1 for placing the trapezoidal block 5 and the wedge-shaped clamping block 2 is "H" shaped. A cover plate 6 is provided on the upper surface of the base 1 corresponding to the middle of the “H”-shaped groove, and the cover plate 6 covers the trapezoidal block 5 and a part of the wedge-shaped clamping block 2 in contact with it.

When in use, the spot welding sample is clamped between the upper and lower clamp bodies. After the spot welding sample is clamped, the loading holes of the upper and lower locking discs are designed on a circle, and the center of the circle is the center of the welding point of the sample, which ensures that the tensile force applied by the testing machine to the loading hole will pass through the center of the welding point of the sample, so that The sample is stressed uniformly and symmetrically. The direction of the load can be from 30° angle to the sample to the direction perpendicular to the sample, that is to achieve from 30° composite loading to pure tensile loading. Since this fixture is used for multidirectional loading of spot welding samples, there are five sets of loading holes on the lock plate 7. When loading through the loading holes of 30°, 45°, 60°, and 75°, the spot welding The solder joints of the sample are in the combined tension-shear loading state, that is, the multi-directional loading test can be carried out on the sample.

The fixture locates the sample by the side of the positioning block 3 (one positioning point, restricting the front and rear directions), the inner surface of the base 1 (two positioning points, restricting the left and right directions and rotating around the vertical direction), and the wedge-shaped clamping block 2 The upper surface (three positioning points, which limit the rotation in the up and down direction and around the two horizontal directions) realizes the six-point positioning of the sample.

The working principle and process of this device: Before clamping the sample, first select the corresponding loading hole according to the angle of multi-directional loading. Use the loading holes to connect the upper and lower clamps with the upper and lower chucks of the uniaxial testing machine respectively, and the loading holes of the upper and lower lock discs 7 are on a circle. Then adjust the position of the wedge-shaped clamping block 2 so that there is a certain distance between the clamping surface and the clamping surface of the base 1, which is convenient for placing the sample. The sample is placed in the lower clamp body 9, and one end side is close to the positioning block 3 to realize the positioning of the sample in the clamp. Then turn the transmission screw 4 of the lower clamp body 9, the transmission screw 4 pushes the trapezoidal block 5 to move forward, and the trapezoidal block 5 pushes the wedge-shaped clamping block 2 to move to the left and right ends to clamp the sample through the contact of the inclined surface. Raise the lower chuck of the testing machine so that the lower clamp body 9 that has clamped the sample is close to the upper clamp body 8 . When raised to a proper position, the sample enters the upper clamp body 8, and the transmission screw of the upper clamp body 8 is turned to make the upper clamp body 8 clamp the sample. This achieves clamping of the specimen.

The clamping structure of this fixture is a wedge-shaped clamping block 2 with a textured knurled clamping surface. When the transmission screw 4 is turned, the trapezoidal block 5 pushes the two wedge-shaped clamping blocks 2 to move left and right at the same time, and There is a gap between the front end of the transmission screw 4 itself and the dovetail groove of the trapezoidal block 5, so this design can ensure the centering of the sample clamping. Ensure that both ends of the two samples are clamped at the same time, and there is no inconsistency in clamping.

The advantages of the present invention are: 1) the structure is simple, compact and practical, and it takes up less space, and the sample can be replaced without removing the clamp, and the operation is relatively simple; Multi-directional composite loading; 3) The clamping surfaces of the base 1 and the wedge-shaped clamping block 2 are both knurled to ensure the clamping degree of the sample; 4) This clamping method makes both ends of the sample clamped at the same time , to avoid the situation that one end is clamped and the other end is not clamped, which can ensure the centering of the sample clamping.

Description of drawings

Figure 1 Schematic diagram of complete fixture

The structural representation of clamp body 8 on Fig. 2

The structural schematic diagram of the lower clamp body 9 in Fig. 3 (remove the cover plate 6)

Figure 4 Parts diagram of wedge clamping block

Figure 5 Schematic diagram of cross-shaped spot welding sample

In the figure: 1. Base, 2. Wedge-shaped clamping block, 3. Positioning block, 4. Transmission screw, 5. Trapezoidal block, 6. Cover plate, 7. Lock plate with loading hole, 8. Upper clamping body 8, 9, the lower clamp concrete 9

Detailed ways

Embodiments of the present invention will be specifically described below with reference to FIG. 1 to FIG. 5 .

This embodiment mainly includes an upper clamp body 8 and a lower clamp body 9, and the upper clamp body 8 and the lower clamp body 9 are two independent similar structures. Wherein, the lower clamp body 9 mainly includes a base 1, a trapezoidal block 5, a wedge-shaped clamping block 2, and a lock plate 7, and an "H"-shaped groove is arranged on the upper surface of the base 1, and the groove is opposite to the upper surface. The centerline of the surface is symmetrical, the trapezoidal block 5 and the wedge-shaped clamping block 2 are arranged in the groove, the centerline of the trapezoidal block 5 coincides with the centerline of the upper surface of the base 1, and a dovetail groove is arranged on the bottom surface of the trapezoidal block 5 . On the side of the base 1, along the axial direction with the trapezoidal block 5, there is a threaded transmission screw 4, one end of the transmission screw 4 is arranged in the dovetail groove of the bottom surface of the trapezoidal block 5, and the trapezoidal block 5 is on the transmission screw 4 It can slide along the centerline of the upper surface of the base 1 under the push. Both sides of the slope of the trapezoidal block 5 are symmetrically provided with wedge-shaped clamping blocks 2, the slope of the wedge-shaped clamping block 2 can be matched with the slope of the trapezoidal block 5, and the wedge-shaped clamping block 2 can be pushed by the slope of the trapezoidal block 5 Sliding along the direction perpendicular to the centerline of the trapezoidal block 5, a rectangular groove is formed between the other surface of the wedge-shaped clamping block 2 away from the trapezoidal block 5 and the base 1 for placing spot welding samples. The above-mentioned structure of the lower clamping body 9 is the same as that of the upper clamping body 8, the difference is that the above-mentioned parts are located on the lower surface of the upper clamping body 8 and the positions of the locking disc 7 are different, and the locking disc 7 of the lower clamping body 9 is located on the base 1. The lower surface is perpendicular to the centerline of the trapezoidal block 5, and the locking disc 7 of the upper clamp body 8 is located on the upper surface of the base 1 and coincides with the centerline of the trapezoidal block 5. The locking disc 7 is provided with a loading hole.

The shape of the base 1 is a cuboid, and a cover plate 6 is provided in the middle of the “H” shaped groove on its upper surface. The cover plate 6 covers the trapezoidal block 5 and a part of the wedge-shaped clamping block 2 in contact with it. , the cover plate 6 is fixed on the base 1 by screws, and plays the role of fixing the trapezoidal block 5 and the wedge-shaped clamping block 2 in the vertical direction.

A positioning block 3 is provided on the upper surface of the base 1 of the lower clamping body 9 and on the side close to the rectangular groove. The positioning block 3 is located in a small groove opened on the upper surface of the base 1 , and when the test piece is clamped, the test piece leans against the side of the positioning block 3 . The distances from the surface of the positioning block 3 adjoining the test piece to the front and rear sides of the base 1 are 47.3 mm and 72.7 mm, respectively.

The shape of the lock plate 7 is fan-shaped, and there are five sets of loading holes on it along the circumferential direction at 30°, 45°, 60°, 75°, and 90° with the base 1. After the spot welding sample is clamped, the upper and lower The loading holes of the lock plate are distributed on a circle, and the center of the circle is the center of the solder joint of the sample.

Claims (6)

1, a kind of cross point welding sample multidirectional fatigue loading fixture is characterized in that: include the also separate lower clamp body (9) of two structural similarities, go up clamp body (8); Wherein, lower clamp body (9) includes pedestal (1), trapezoid block (5), wedge clamping block (2), lock collar (7), upper surface at pedestal (1) is provided with a groove, trapezoid block (5), wedge clamping block (2) is arranged in this groove, the upper surface center line of the center line of trapezoid block (5) and pedestal (1) coincides, axis direction in the side of pedestal (1) along trapezoid block (5) is provided with transmission screw (4), transmission screw (4) cooperates with the bottom surface of trapezoid block (5), and trapezoid block (5) can slide along the upper surface center line of pedestal (1) under the promotion of transmission screw (4); Symmetria bilateralis on two inclined-planes of trapezoid block (5) is provided with wedge clamping block (2), the inclined-plane of trapezoid block (5) can match with the inclined-plane of wedge clamping block (2) and contact, wedge clamping block (2) can be under the promotion on trapezoid block (5) inclined-plane along sliding with the perpendicular direction of the center line of trapezoid block (5), wedge clamping block (2) deviates from and forms rectangular groove between the side of trapezoid block (5) and the pedestal (1), is used to place spot-welding sample; The said structure of lower clamp body (9) is identical with last clamp body (8), and difference is that said structure is positioned at the lower surface of clamp body (8); The upper surface of the lower surface of lower clamp body (9) and last clamp body (8) all is provided with lock collar (7), and lock collar (7) is provided with five covers and loads the hole.

2, a kind of cross point welding sample multidirectional fatigue loading fixture according to claim 1, it is characterized in that: described lock collar (7) is for fan-shaped, along the circumferential direction having on it with pedestal (1) becomes 30 °, 45 °, 60 °, 75 °, 90 ° five covers to load the hole respectively, behind the spot-welding sample clamping, the loading pore size distribution of lock collar is on a circumference up and down, and the center of circle is the solder joint center of sample.

3, a kind of cross point welding sample multidirectional fatigue loading fixture according to claim 1, it is characterized in that: the lock collar (7) of described lower clamp body (9) is perpendicular with the center line of trapezoid block (5), and the lock collar (7) of last clamp body (8) coincides with the center line of trapezoid block (5).

4, a kind of cross point welding sample multidirectional fatigue loading fixture according to claim 1 is characterized in that: a side of the upper surface of the pedestal (1) of described lower clamp body (9), close rectangular recess is provided with locating piece (3).

5, a kind of cross point welding sample multidirectional fatigue loading fixture according to claim 1 is characterized in that: be used to place the groove of trapezoid block (5) and wedge clamping block (2) on the described pedestal of going up in clamp body (8) and the lower clamp body (9) (1) for " H " shape and with respect to upper surface center line symmetry.

6, according to claim 1 or the described a kind of cross point welding sample multidirectional fatigue loading fixture of claim 5, it is characterized in that: the middle part of lower surface correspondence " H " connected in star of the pedestal (1) in last clamp body (8) is provided with cover plate (6).

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