Hydraulic control system of lathe modified broaching machine and structural stability of main frame

*Communication contacts use the idle old lathe to convert into a high-efficiency broaching machine, which is conducive to saving production costs and revitalizing useless assets, and is also conducive to environmental protection and meets the requirements of green manufacturing. The design and modification of the LJ8510/CGL broaching machine is a good example. Shown is the outline drawing of the broaching machine, which is mainly composed of the old lathe bed and the headboard case with 4m long guide rail. The thin-walled hollow main frame 4 and the original lathe large carriage housing are modified when the broaching bed 4 is modified. Mainly, and the main slide plate 10 with the broach chuck is installed; the main cylinder 1 passes through the through hole in the left end of the bed 3 (ie, the original headstock) (the enlarged machining hole of the original spindle shaft hole) is installed in The left end of the main frame 4, the piston rod and the main sliding plate 10 are connected by a special joint, push or pull the main sliding plate 10, and can move along the horizontal rail on the bed 3 in the hollow body of the main frame, and the maximum working stroke is 1400 mm. power.

Movement, the ratio of the cylinder bore D of the main cylinder to the diameter d of the piston rod is d/D = or the valve of the electro-hydraulic valve when the broach is stopped.) The stability of the ublisi component should be calculated according to the following formula: the turret return speed is the broaching speed. 31kW, the whole system has a certain power reserve. 2 Hollow thin-walled slender main phase. The main frame 4 is composed of two 80mm left and right end plates joined together to form a single core cross section as shown in (a). The thin-walled hollow section is composed of two joints, and the axis x is a truncated section (also the section of the split channel steel is resistant to bending moments, the strong axis of the limbs, the 2 channel steel section is resistant to the bending moment weak axis; the bed 3 is fastened and connected with the main The cylinder 1 is supported on the guide rail of the bed 3 and is end-to-end.

Understand the famous cutting force formed by the main cylinder pulling the broach, when the broaching keyway to the top surface of the keyway is the point eccentric distance e from the hole of the workpiece (also the disk position), and the axial direction (upper, because the main frame is In a hollow thin-walled steel structure project, the allowable stress of the component material is composed of two limbs, MPa; Px is the stability coefficient of the axial compression member of the axis x in the plane of the bending moment, which is related to the conversion slenderness ratio U. After the calculation, the % value of the table 31 can be calculated or checked; U is the converted slenderness ratio, and the combined axial compression member has a large shear deformation when bent around the imaginary axis x, and the critical force on the bending layer Effective large impact, so the calculation should be based on the conversion length ratio to consider this effect, 'into x is the combined component to the virtual axis x slenderness ratio, \= Lx / ix; into 1x is the weak axis X1 of the limbs Slenderness ratio, Xix=Lx, Lix is the free length of the combined member along the axis x limbs along the axis xi, mm; the radius of inertia, mm; I3mx, fwy are the bending moment plane, the bending moment plane External equivalent bending moment coefficient, for both transverse and end bending moments, Ly is the combined component axis y direction Free length, mm; q is the unit length of the assembly from gravity, N/mm; e is the eccentric moment, mm; Wx, Wy are the cross-Section Bending resistance of the combined member along the axis x, the axis y, mm3. At the time of the structure and process requirements of the workpiece, the eccentric position of the top surface of the keyway from the hole is not necessarily in the direction of the section axis x or y shown in (a), and may be at any arbitrary angle a in the section. In the case of the axial force N and the eccentric moment e, the maximum position of the pulled key groove can be obtained. Let =0, the unstable state is mainly in the form of single limb instability, so it is not necessary to perform the bending moment to the out-of-plane whole Stability calculation, and the stability of the single limb should be calculated. As long as the stability of the limb in both directions is ensured, the stability of the whole component outside the plane of the bending moment is guaranteed.

2.2 Single (minute) limb in-plane stability bending moment in the weak axis xi plane (around the y-axis) of the channel steel (solid double) bending member stability of the following formula 13 ft with bending moment in the plane The stability coefficient of the axial compression member (channel steel) is related to the slenderness ratio. After the calculation, the 9ly value can be calculated or checked; Liy is the free length of the limb 1 in the y direction, mm; ily is the fraction The radius of inertia of the limb 1 around the axis y, mm; Wiy is the bending resistance coefficient of the limb 1 in the y-direction section, mm3; Ai is the fractional (single) limb section machine mm2; 2.3 points (single) limb out-of-plane stability 9lx For the bending moment, the stability coefficient of the out-of-plane axial compression member (channel steel) is related to the slenderness ratio Mx. After calculating Mx, the table can be calculated or looked up; h, b, t are the height of the trough section, respectively. Flange width and average thickness (see (a)), mm; large aperture Y110, according to the national standard, the top surface of the keyway to the hole moment e=61.4, the main frame of the machine tool is made of 30a channel steel as the two points of the component Limbs, its single limb section b = 85mm, h = 30, t when 9. = 2380mm, combined components required to allow overload 1.25 rated load, in the design calculation and points According to the engineering design convention, the calculated load N is greater than the allowable overload load, which is 1.5 times of the rated load. For the LJ8510/CGL broaching machine, N=150kN, the main frame of the machine tool is finished with the formulas (1)~(4). From the above analysis and calculation, it can be considered that the designed and modified LJ8510/CGL broaching machine main frame has reasonable design, good structural stability, can withstand large broaching load, has certain bearing capacity, and the hydraulic control system meets the needs of broaching work. The test run is normal, running for 4 hours, the system oil temperature rises < 20 °C; the quality of the whole machine meets the national standard requirements, it has been used in production, and its commercial manufacturing cost is only 1/2 or less of the same tonnage broaching machine. The design calculation principle and analysis method of the machine are recommended.