JPS5940153Y2 - Impact-resistant tool with spherical joint surface - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an impact-resistant tool in which two metal bodies having different diameters and areas are friction-welded with strong joint strength.

In tools, etc., which conventionally consist of a small-diameter shaft and a polygonal head with a larger diameter or distance across opposite sides than the shaft, friction welding of large-diameter and small-diameter materials is used to save materials and shorten machining time. There was a case.

However, in friction welding, as shown in FIG. 1, the diameter d1 of the welded materials AB. d2 is almost the same, and in order to make the hardened layer and deteriorated layer g that occur on both sides of the joint surface f uniform after joining, in the case of steel materials, reheating and tempering treatment are performed afterwards. Ta.

In addition, it has been impossible to join tempered materials together by a method such as friction welding without producing a deteriorated layer.

The present invention provides shock-resistant tools such as various punches, extrusion pins, nailer drivers, etc., in which the material once tempered has a friction bonding surface that does not substantially reduce the strength of the deteriorated layer. The purpose is to

The present invention will be explained by giving examples.

FIG. 2 is a diagram showing the working process of a conventional push-out pin.

The extrusion pins currently used in die casting, press molds, etc. are made by upsetting the head 2 from a tempered round bar 1 as shown in Figure 2, annealing and softening only the head at an appropriate temperature, and then machining it. has been done.

Due to its characteristics as an extrusion pin, the shaft has a hardness of HRC38-45.
The head is desired to have an HRC of about 25 to 30, and a friction bonded product as shown in FIG. 1 was not put into practical use because of its weak strength and risk of breakage.

Therefore, most of the manufacturing methods used were as shown in Figure 2.

However, even in this process, it is not possible to soften only the head during the annealing process of the head, and the heat is also conducted to the shaft, making it impossible to prevent the part of the shaft near the head from being cut, resulting in bending, etc. This resulted in defects.

The present invention avoids the drawbacks of conventional manufacturing methods and compensates for the defects in the joints of commonly practiced friction welding.

That is, as shown in FIG. 3, a tempered shaft portion having a small diameter is directly joined to the annealed and softened head C of the extrusion pin described above.

The shape of the welding surface D at this time may be a convex shape connected by a straight line or a curve as shown in flat a or b, but the shape of the shaft welding surface, crimping speed and crimping pressure during friction welding may By adjusting the diameter of the shaft portion as D, it is possible to obtain a substantially spherical joint surface f with a depth h≦0.21D as shown in FIG. It is important that it is included in the

The shape of the end face of the material on the shaft side is as shown in Figure 3 a, b, and c, and the thrust for frictional heating is 400 to 1000 kgt.
/c♂ and crimping thrust of 700 to 2400 kgt/cn
Friction welding was performed by changing the range of (), and the shear step strength and shape of the joint surface were investigated.

As a result, the shapes a and c of the end faces have almost no effect on the strength and the penetration depth of the spherical joint surface, and the thrust for heating and crimping thrust have a large influence on this strength and the shape of the joint surface, and therefore the strength and the penetration depth of the joint surface are greatly affected. It was found that the depth h has a strong correlation.

This depth h increases as the heating thrust and the pressure bonding pressure increase, and among these, the influence of the heating thrust is large.

The heating thrust needs to be adjusted depending on the material of the material to be pressed, but its value may be approximately within the above range.

The crimping pressure needs to be at least twice the heating thrust.

Therefore, by selecting the heating thrust, the penetration depth, that is, the bonding strength, can be kept within a large range.

FIG. 5 is an example showing the relationship between penetration depth h and bonding strength.

According to this, the shear strength is large when h≦0.21D, and h
It can be seen that the value decreases rapidly at >0.2LD.

The reason for this is not clear, but a suitable combination of contact pressure and temperature is required for strong welding, and perhaps if the amount of penetration is too large, the weld area becomes a force intensifier, while the large radius area becomes hot due to friction. This is thought to be because the material easily flows out in the axial direction during pushing, making it difficult to generate high surface pressure.

This approximately spherical surface with h = 0.21D is a spherical surface whose vertex is a diagonal that is about 90' to the diameter of the circle where the end face of the material C and the cylindrical surface of the material intersect, as shown in Figure 4. It is interesting to see from the drawing.

In the case of such a joint surface, the tempered shaft part has uniform mechanical strength over the entire shaft length L from the tip to the bottom of the neck, and the head part has a large cross-sectional area and is an annealed part. There is no risk of breakage even under mechanical stress.

Practically speaking, there is no problem in terms of strength if friction welding is used as is, but annealing may be performed if necessary.

However, this is not desirable if there is a risk that the strength of the shaft portion will be reduced.

As explained above, when joining two metal bodies with different cross-sectional areas, strength is improved by friction welding so that the joint surface enters the metal body with the larger cross-sectional area or joint surface by h≦0.21D. This is a tool with a strong welded structure.

In addition, when joining various punches and nailer drivers, products that are friction-welded by pushing the roughly spherical joint into the larger cross-section have strong joint strength and do not bend, making them important tools. Even when applied, satisfactory parts can be constructed.

[Brief explanation of the drawing]

FIG. 1 shows a conventional example of friction welding. FIG. 2 shows a working process diagram of the ejector pin. FIG. 3 shows an example of the shape of the joint of the present invention. FIG. 4 is a diagram showing details of joining of an embodiment of the present invention. FIG. 5 is a diagram showing the bonding strength when the indentation depth h is changed.

Claims (1)

[Scope of utility model registration request] By friction welding, one of these joints has a circular cross section, and the other has a stepped shape extending outward from the circular cross section.In a metal impact-resistant tool that receives an impact load on this joint, friction The shape of the joint surface is made into a substantially spherical shape in which a member having a circular cross section enters a member having a stepped enlarged part, and the penetration depth is 0.21 times or less the diameter of the circular shape. An impact-resistant tool with a characteristic spherical joint surface.