Inner support fixing device

The invention provides an inner support fixing device. The inner support fixing device comprises a driving mechanism, a pull rod connected with the driving mechanism, a sliding base body, a pluralityof sliding blocks, and a supporting mechanism, wherein the side, away from the driving mechanism, of the pull rod comprises an inner support end; the side, away from the driving mechanism, of the pullrod is sleeved with the sliding base body, a plurality of sliding grooves are formed in the surface, away from the driving mechanism, of the sliding base body at intervals along the periphery, and the sliding grooves extend in the radial direction of the sliding base body; the multiple sliding blocks are connected with the multiple sliding grooves in a sliding mode, the multiple sliding blocks are arranged in a surrounding mode to form a sliding block assembly with a hollow part, the sliding block assembly is arranged at the inner support end in a sleeving mode, and the sliding block assemblyis sleeved with a workpiece; and the supporting mechanism is connected with the side, away from the sliding grooves, of the sliding base body. The inner support fixing device is simple in structure,the workpiece with a cavity can be conveniently clamped and fixed, clamping positions do not need to be added, clamping errors are reduced, and machining precision is improved; and in addition, universality is high, and the device can be suitable for workpieces of different sizes and shapes.