Description Rotor Technical Field The invention relates to a rotor. Background of the Invention A motor rotor comprises a rotating shaft and a lamination assembly arranged on the rotating shaft by penetration, wherein the lamination assembly is formed by superposition and connection of a plurality of laminations, a connecting structure between the laminations and the rotating shaft is generally provided with ribs on the rotating shaft, the laminations are fastened on the rotating shaft, or clamping teeth are arranged in a lamination through hole, and the laminations are clamped on the rotating shaft through the clamping teeth. The stability and the symmetrical balance of the two connection ways need to be improved. Summary of the Invention The technical problem to be solved by the invention is to provide a rotor which is firm in connection between laminations and a rotating shaft and good in stability and symmetrical balance of the rotor. In order to solve the technical problem, the invention adopts the following technical scheme: the rotor comprises a rotating shaft and a lamination assembly, and the rotor is characterized in that the lamination assembly is formed by symmetrically penetrating and arranging the same number of left laminations and right laminations on the rotating shaft, wherein the left lamination on the innermost end is conjoint with the right lamination on the innermost end, a rotating shaft through hole I is arranged at the center of the left laminations, the rotating shaft through hole I is circumferentially provided with a plurality of clamping teeth I, the plurality of the clamping teeth I tilt to the outer end of the rotating shaft along the axial direction of the rotating shaft to form a circular truncated cone structure, a rotating shaft through hole II is arranged at the center of the right laminations, the rotating shaft through hole II is circumferentially provided with a plurality of clamping teeth II, and the plurality of the clamping teeth II tilt to the outer end of the rotating shaft along the axial direction of the rotating shaft to form the circular truncated cone structure. Preferably, the height of each circular truncated cone is 0.1-1mm. The left laminations and the right laminations of the rotor are symmetrically distributed, and the plurality of the clamping teeth on each of the rotating shaft through holes of the left laminations and the right laminations tilt to the outer end of the rotating shaft along the axial direction of the rotating shaft for forming the circular truncated cone structure, thereby having the unidirectivity, enabling the connection 1 between the laminations and the rotating shaft after the assembly to be firm and less prone to outward deviation, and enabling the stability and the symmetrical balance of the rotor to be better. Brief Description of the Drawings In combination of the following figures, the invention is further described. Figure 1 is a schematic diagram of structure of rotor of the invention; Figure 2 is a schematic diagram of structure of left lamination of the invention; Figure 3 is an A-A view in Figure 2. Detailed Description of the Invention As shown in Figure 1, a rotor of the invention comprises a rotating shaft 3 and a lamination assembly, and the lamination assembly is formed by symmetrically penetrating and arranging the same number of left laminations 1 and right laminations 2 on the rotating shaft, wherein the left lamination on the innermost end is conjoint with the right lamination on the innermost end, as shown in Figure 2 and Figure 3, a rotating shaft through hole I 11 is arranged at the center of the left laminations 1, the rotating shaft through hole I is circumferentially provided with a plurality of clamping teeth I 4, the plurality of the clamping teeth I tilt to the outer end of the rotating shaft along the axial direction of the rotating shaft to form a circular truncated cone structure, the structure of the right laminations is the same with that of the left laminations, a rotating shaft through hole II is arranged at the center of the right laminations, the rotating shaft through hole II is circumferentially provided with a plurality of clamping teeth II, the plurality of the clamping teeth II tilt to the outer end of the rotating shaft along the axial direction of the rotating shaft to form the circular truncated cone structure, and the height of each circular truncated cone is 0.1-1mm. The left laminations and the right laminations of the rotor are symmetrically distributed, and the plurality of the clamping teeth on each of the rotating shaft through holes of the left laminations and the right laminations tilt to the outer end of the rotating shaft along the axial direction of the rotating shaft for forming the circular truncated cone structure, thereby having the unidirectivity, enabling the connection between the laminations and the rotating shaft after the assembly to be firm and less prone to outward deviation, and enabling the stability and the symmetrical balance of the rotor to be better. The invention further provides a production process of the rotor, which comprises the following steps: 1) Punching laminations and forming rotating shaft through holes with clamping teeth; 2) Stamping the clamping teeth on the laminations to form circular truncated cone structures; 3) Selecting the laminations in one half of the number of the laminations for constituting a lamination assembly as left laminations, clamping the rotating shaft 2 with the left laminations through a press and simultaneously mutually splicing the left laminations, wherein the clamping teeth of the circular truncated cone structure on the left laminations face towards the outer end of the rotating shaft; 4) Selecting the laminations in one half of the number of the laminations for constituting the lamination assembly as right laminations, clamping the rotating shaft with the right laminations through the press and simultaneously mutually splicing the right laminations, wherein the left lamination on the innermost end is conjoint with the right lamination on the innermost end, and the clamping teeth of the circular truncated cone structure on the right laminations face towards the outer end of the rotating shaft. 3