JP2529286Y2 - Spot welding strength confirmation device - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a method for spot welding in which one end of a plurality of test pieces are overlapped with each other to check whether or not the spot welding is performed normally, and two other ends of the test pieces are welded. The present invention relates to a spot welding strength confirming device for measuring a breaking strength by applying a tensile force while gripping a workpiece.

[0002]

2. Description of the Related Art For example, in an automobile production line,
Welding of the vehicle body is performed by a welding robot or a stationary spot welding machine.However, the welding tip used for such spot welding deteriorates due to repeated use and the welding performance decreases, so welding of a predetermined number of vehicle bodies is completed. It is necessary to check the strength of the weld every time. For this purpose, spot welding strength using a test piece has been conventionally confirmed.

That is, as shown in FIGS. 4 and 5, a plurality of (for example, three) strip-shaped test pieces P having the same material and the same plate thickness as a work being mass-produced are superposed at an angle to each other. Spot welding them under the same conditions as in mass production. Then, after the test piece P is pulled left and right manually to separate it, the nugget diameter of the weld is measured, and if the nugget diameter exceeds a reference value, the welding strength of mass-produced products can be guaranteed.

[0004]

However, in the conventional manual method described above, if the test piece is thin, the welding strength can be confirmed without consuming a large amount of labor. When the thickness is increased, it becomes difficult to separate the test piece by hand, and furthermore, there is a problem that the actual breaking strength of the welded portion cannot be known by indirect strength confirmation by measuring the nugget diameter.

For this purpose, it is conceivable to check the strength of the test piece using an Amsler universal testing machine. However, it is necessary to install an amsler universal testing machine, which is a large-sized and expensive multifunctional general-purpose machine, in each welding line. However, not only is there a problem in terms of cost and space, but also there is a problem that it takes a long time to grip the test piece with the chuck, and it is difficult to perform a test in a short time.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a spot welding strength checking device which has a simple structure and allows easy attachment and detachment of a test piece.

[0007]

In order to achieve the above-mentioned object, according to the present invention, two other ends of a plurality of test pieces having one end overlapped and spot-welded are respectively held by a pair of holding means. A spot welding strength confirming device configured to measure the breaking strength of a welded portion by relatively moving these gripping means so as to be separated from each other by a driving source, wherein each of the gripping means is disposed on a surface of a test piece. The first feature is that a gripping surface that forms an obtuse angle and a pressing member that presses and fixes the other end of the test piece to the gripping surface are provided.

[0008] In addition to the first feature described above, the present invention provides:
A second feature is that a conical protrusion and an annular pressing surface surrounding the protrusion are provided at the tip of the pressing member, and a concave portion is provided at a position corresponding to the protrusion on the gripping surface.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the present invention. FIG. 1 is an overall side view of the spot welding strength checking device, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. It is a principal part enlarged view of FIG.

A cushioning member 2 is provided above a gantry 1 standing on the floor.
The right half of the upper surface of the substrate 3 supported via
A pair of guide rails 4 is laid along the longitudinal direction of the guide rail. The movable base 6 slidably supported on the guide rail 4 via the linear block 5 includes a gripping means supporting portion formed by assembling a bottom plate 7a, a pair of side plates 7b, a front plate 7c, a support plate 7d, and a reinforcing plate 7e. 7 is provided. A stopper 8 made of an elastic material capable of contacting the movable base 6 is provided at a right end of the substrate 3 via a bracket 9.

On the left side of the upper surface of the substrate 3, there is provided a holding means support portion 10 which is an assembly of a bottom plate 10a, a pair of side plates 10b, a front plate 10c, and a support plate 10d, and a bracket 11 is provided between the pair of side plates 10b. , The hydraulic cylinder 12 is supported. The hydraulic cylinder 12 extends rightward through the front plate 10 c, and its tip is supported by the head of a support bolt 13 planted on the substrate 3. Hydraulic cylinder 1
A piston rod 14 protruding rightward is slid by pressure oil supplied from a manual hydraulic pump (not shown) inside the inside of the cylinder 2, and a front plate 7 c of the right gripping means support portion 7 is provided at the end thereof.
Is attached. The bottom plate 10a
Is provided with a pair of side plates 10e and a rear plate 10f. A back-up bolt 16 screwed to the rear plate 10f is brought into contact with the rear end of the hydraulic cylinder 12 to receive a reaction force acting on the hydraulic cylinder 12. Is done. Hydraulic cylinder 12
Is provided with a stylus-type pressure gauge 17 for detecting the magnitude of the hydraulic pressure when a test piece P described later is separated.

The test pieces P used in the present apparatus are overlapped at one end so that the two pieces are aligned in a straight line, and further spot-welded with the abutment plate P 'overlaid thereon. Support plate 7 of one gripper support portion 7
d is provided with a movable gripper Cm for gripping the gripper Pc of one test piece P, and the support plate 10d of the other gripper supporter 10 grips the gripper Pc of the other test piece P. Holding means Cf is provided. These two gripping means Cm and Cf have the same structure,
They are arranged to face each other.

FIG. 3 shows a fixed gripping means Cf, in which a gripping block 18 fixed to the support plate 10d is formed with a slit into which the gripping portion Pc of the test piece P is inserted.
A grip surface 18a for fixing the grip portion Pc is formed on one wall surface of the slit. A pressing bolt 19 as a pressing member is screwed into the holding block 18 from the opposite side of the holding surface 18a. At the center of the tip of the pressing bolt 19, a conical projection 19a and an annular pressing surface 19b are provided so as to surround the outer periphery thereof. Also, grip block 1
A conical concave portion 18b is formed on the gripping surface 18a of the corresponding to the projection 19a of the pressing bolt 19. As is clear from FIG. 1, the gripping surface 18a of the gripping block 18
Are formed to be inclined so as to form an obtuse angle α with the surface of the test piece P.

The structure of the movable gripping means Cm is the same as the structure of the fixed gripping means Cf, and a description thereof will not be repeated.

Next, an embodiment of the present invention will be described.

The grips Pc of the two test pieces P welded together are bent, and the grips Pc are inserted into the slits of the gripping block 18 of the movable gripping means Cm and the fixed gripping means cf. Subsequently, when the pressing bolt 19 is tightened, the grip portion Pc pressed by the conical projection 19a formed at the tip thereof is slightly deformed, and the concave portion 1 of the grip surface 18a is deformed.
8b and a gripping portion P of the test piece P between the pressing surface 19b around the projection 19a and the gripping surface 18a.
c is clamped and fixed.

In this way, the gripping portions Pc of the two test pieces P are respectively connected to the movable gripping means Cm and the fixed gripping means Cf.
After the hydraulic cylinder 12 is driven to extend the piston rod 14, the front plate 7 c is pressed by the contact member 15 of the piston rod 14, and the movable gripping means Cm and the movable base 6 are moved from the fixed gripping means Cf. The two test pieces P move in the direction in which they are separated from each other, and are pulled right and left and break from the welded portion Pw. At the same time that the welded portion Pw of the test piece P breaks, the movable gripping means Cm pushed rightward by the pressing force of the hydraulic cylinder 12 stops when the movable base 6 comes into contact with the stopper 8. Then, the magnitude of the hydraulic pressure acting on the hydraulic cylinder 12 when the welded portion Pw of the test piece P is broken is detected by the needle-type pressure gauge 17, and the strength of the welded portion is confirmed based on the detection result.

Now, as described above, the two gripping means Cm, Cf
When the test piece P is gripped and pulled, the gripping portion Pc of the test piece P is gripped because the surface of the test piece P, that is, the gripping surface 18a of the gripping block 18 is inclined with respect to the pulling direction of the test piece P. Even if the force is small, it is possible to sufficiently oppose the pulling force, so that both gripping means Cm and Cf can be reduced in size and weight.

Further, the projection 19a of the pressing bolt 19 and the concave portion 18b of the gripping surface 18a form the grip portion P of the test piece P.
c is slightly deformed, and the gripping portion Pc is clamped and fixed between the pressing surface 19b of the pressing bolt 19 and the gripping surface 18a. Therefore, in combination with the above-described effect of the inclined gripping surface 18a, The test piece P can be reliably gripped with a slight tightening force of the pressing bolt 19.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and does not depart from the present invention described in the claims for utility model registration.
Various small design changes can be made.

For example, instead of the pressing bolt 19, a pressing member having the same tip shape may be driven forward and backward by an actuator such as a cylinder. Further, an electric hydraulic pump may be used instead of the manual hydraulic pump as a hydraulic pressure source for driving the hydraulic cylinder 12.

[0023]

As described above, according to the first aspect of the present invention, the gripping means forms an obtuse angle with respect to the surface of the test piece, and the other end of the test piece is fixed to the gripping surface by pressing. Since the test piece is provided, the test piece can be securely fixed with a small gripping force, so that the gripping means can be reduced in size and weight, and the test piece can be quickly gripped.

According to a second feature of the present invention, a conical protrusion and an annular pressing surface surrounding the protrusion are provided at the tip of the pressing member, and a concave portion corresponding to the protrusion on the grip surface is provided. Therefore, the test piece can be partially deformed by the projections and the concave portions, and the outer periphery of the deformed portion can be pressed between the pressing surface and the gripping surface and securely fixed.

[Brief description of the drawings]

FIG. 1 is an overall side view of a spot welding strength checking device.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is an enlarged view of a main part of FIG. 1;

FIG. 4 is a side view of a conventional test piece.

FIG. 5 is a plan view of a conventional test piece.

[Explanation of symbols]

 18a: gripping surface 18b: concave portion 19: pressing bolt (pressing member) 19a: projection 19b: pressing surface Cf: gripping means (fixed gripping means) Cm: Holding means (movable holding means) P ... Test piece

Claims (2)

(57) [Scope of request for utility model registration] 1. A pair of gripping means (Cm, Cf) respectively gripping two other ends of a plurality of test pieces (P) which are spot welded with one ends overlapped, and these gripping means (Cm, Cf). ) Are relatively moved by a driving source so as to be separated from each other, and the fracture strength of the welded portion is measured, wherein each of the gripping means (C
m, Cf) form an obtuse angle with the surface of the test piece (P), and a pressing member (1) that presses and fixes the other end of the test piece (P) to the grip surface (18a).
9) A spot welding strength checking device, characterized in that: 2. A conical projection (19a) and an annular pressing surface (19b) surrounding the projection (19a) are provided at the tip of the pressing member (19), and the projection (19a) on the gripping surface (18a) is provided. 2. The spot welding strength checking device according to claim 1, wherein a concave portion (18b) is provided at a position corresponding to (1).