Self-expansion clamp

Abstract

The invention relates to a self-expansion clamp which is characterized by comprising a mandrel, a diameter-variable sleeve and a pressing screw nut, wherein the mandrel is provided with a taper surface; the diameter-variable sleeve sleeves the taper surface of the mandrel; the pressing screw nut is used for tightly pressing the diameter-variable sleeve to enable the diameter-variable sleeve to slide in the axial direction of the mandrel; grooves are formed in the outer wall of the diameter-variable sleeve; the grooves comprise annular grooves which are formed in the outer circumferential direction of the diameter-variable sleeve; a plurality of annular grooves are uniformly formedin the axial direction of the diameter-variable sleeve. Due to adoption of the grooves in the outer wall of the diameter-variable sleeve, a plurality of support blocks partitioned by the grooves are formed in the outer wall of the diameter-variable sleeve, a small supportsurface is formed in each supportblock, and a support block which is relatively largely stressed can be compressed in the radial direction after a workpiece is clamped, so that certain pressure can be generated between support blocks,which are relatively slightly stressed and do not contact the workpiece, and the workpiece, the contact stress area betweenthe surface of the outer wall of the diameter-variable sleeve and the workpiece is enlarged, the stress uniformity is improved, the workpiece can be stably and reliably positioned, and an independent axial positioning pressing cover structure does not need to arrange.

Description

technical field [0001] The invention relates to a self-expanding clamp. Background technique [0002] The fixture is a process device used to quickly fasten the workpiece in machining to keep the machine tool, tool and workpiece in the correct relative position. It is an indispensable part. With the development of machine tool technology towards high speed, high efficiency, precision and intelligence, the fixture is also High-precision, high-efficiency, and economical requirements are put forward. In the prior art, the common fixture used for disc parts (such as gears) with a central hole is the expansion sleeve mandrel. The expansion sleeve mandrel generally includes a tapered surface. Slidingly fitted expansion core and reducer sleeve, through the compression nut to compress the reducer sleeve to cause radial deformation and then position the workpiece, the expansion sleeve mandrel can adapt to different workpiece inner hole sizes within a certain range for positioning , ...

AI Technical Summary

Problems solved by technology

[0002] The fixture is a process device used to quickly fasten the workpiece in machining to keep the machine tool, tool and workpiece in the correct relative position. It is an indispensable part. With the development of machine tool technology towards high speed, high efficiency, precision and intelligence, the fixture is also High-precision, high-efficiency, and economical requirements are put forward. In the prior art, the common fixture used for disc parts (such as gears) with a central hole is the expansion sleeve mandrel. The expansion sleeve mandrel generally includes a tapered surface. Slidingly fitted expansion core and reducer sleeve, through the compression nut to compress the reducer sleeve to cause radial deformation and then position the workpiece, the expansion sleeve mandrel can adapt to different workpiece inner hole sizes within a certain range for positioning , but the expansion force generated by the mandrel of the expansion sleeve has an amplified relationship with the pre-tightening force applied by the operator to the compression nut. It is difficult to control the pre-tightening force in manual clamping, which will easily cause positioning failure. The surface of the outer wall is a cylindrical surface that matches the surface of the inner hole of the workpiece, that is, the entire surface is positioned with the inner hole of the workpiece. However, due to the limitation of machining accuracy, it is impossible to realize the overall contact between the outer wall surface of the reducing sleeve and the inner hole surface of the workpiece in actual processing. Usually, local clamping points and gaps are generated. Although the radial positioning error of the workpiece can be controlled within the allowable range, the axial positioning stability of the workpiece is poor, and it is easy to cause the workpiece to slip and slip during processing, so as to avoid the above-mentioned Usually, it is necessary to install an axial positioning gland at one end of the mandrel of the expansion sleeve to clamp and position the workpiece axially, resulting in a complicated fixture structure and high production costs. At the same time, one more step of workpiece clamping operation greatly affects the clamp and production efficiency; the overall weight of the clamp increases, which is inconvenient to use and increases the labor intensity of the operator

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