CN203636507U - Measurement device of ram thermal expansion - Google Patents

Abstract

In a measurement device of ram thermal expansion, the connection point of a ram shell and a lead screw group is disposed on a fixed rear end of the ram. The device is characterized by the structure that the ram rear end is linked to the rear end of an aluminum tube, front ends of the aluminum tube and a steel rod are linked at a fixation part of the aluminum tube and the steel rod and the rear end of the steel rod is connected to the measurement device. In the design, the characteristic that the coefficient of thermal expansion of aluminum is two times the coefficient of steel, the ram shell is expanded by a thermal expansion unit to the positive direction with temperature changing, the aluminum tube is expanded by two times to the positive direction simultaneously, the steel rod is also passively moved by two times to the positive direction, but the steel rod itself is expanded to the negative direction by a thermal expansion unit, and the sum of the expansion value and the ram thermal expansion value is equal to the thermal expansion value of the aluminum tube. A reference object of ram thermal displacement is composited, namely that the value collected by the measurement device at the rear end of the steel rod at this moment is just the ram thermal displacement, so that the device takes the place of expensive benchmarking invar steel and manufacturing cost of equipment is obviously reduced.

Description

Measure the device of ram thermal stretching

Technical field

The utility model relates to plant equipment manufacture, and a kind of ram for large-sized gantry boring and milling machine and large-scale vertical milling-lathe machining center utilizes steel, aluminium coefficient of thermal expansion differences to make the object of reference structure of ram, measures the device of ram heat distortion amount.

Background technology

Processing parts complexity on large-sized gantry boring and milling machine and large-scale vertical milling-lathe machining center, process-cycle is long, due to the performance of expanding with heat and contract with cold of metal, when machine tooling, running up of the inner milling spindle of ram produces heat and the part of processing and in working angles, produces heat with cutter and cause ram elongation, when different operating mode, the actual thermal stretching length of ram and machine tool numerical control system setting numerical value there are differences, and cause machining accuracy to reduce; The stroke of ram is longer, and this phenomenon is just more obvious.The method that present stage adopts is generally, the invar that adopts invar alloy namely often to say, utilize the hot expansion system of invar to approach zero, taking invar as absolute value object of reference zero point, the front end of invar and ram front end are fixed, invar rear end connects with measurement mechanism, measure the thermal stretching variable of ram ram in dynamic situation, when ram works long hours, temperature changes, ram length is also different, the data of adopting by ram rear end measurement mechanism, compensate in machine tool numerical control system, revise the position of ram point of a knife point, realize real-Time Compensation, eliminate the side effect that thermal deformation brings.Shortcoming is high as the invar cost of mark post, and under different condition, its thermal coefficient of expansion is not also absolute value zero, and adopts invar to cause the cost of equipment to promote.

Summary of the invention

The purpose of this utility model is to provide a kind of device of measuring ram thermal stretching, utilizes the structure of steel, aluminium coefficient of thermal expansion differences to form ram object of reference, substitutes invar, measures ram thermal stretching value.

Measure the device of ram thermal stretching, setting ram front end is that positive direction, ram rear end are negative direction, ram housing axial drilling, it is characterized in that structure is: get aluminum pipe, rod iron and ram equal length, aluminum pipe, rod iron are installed in ram housing bore, and ram housing and leading screw group binding site be in the fixing rear end of ram, then by client link after ram rear end and aluminum pipe, aluminum pipe front end and rod iron front end connect at aluminum pipe and rod iron fixture place, and rod iron rear end is connected with measurement mechanism.

Distinguishing feature

The device of measuring ram thermal stretching based on material thermal stretching difference characteristic of the present invention, for large-sized gantry boring and milling machine and large-scale vertical milling-lathe machining center, can eliminate ram influence of thermal deformation, can reduce again manufacturing equipment cost.The present invention is that the aluminium that utilizes heat conductivility to be better than steel does heat-conducting medium, makes the heat of ram heated part transmit gradient minimum, and the thermal stretching unit quantity of aluminium is by chance 2 times of steel, good calculating.But the design does not leave control system for this multiple conversion and goes to calculate, but embody with frame mode: the material of rod iron and ram is all steel, thermal stretching unit value is identical, for equivalent, be arranged on aluminum pipe inside and outside, rod iron has driven during by aluminum pipe thermal stretching the thermal stretching unit of a times many, on space, being equivalent to ram is forward and backward series connection, the two is considered as equivalent thermal stretching unit sum, also just in time equate with the thermal stretching unit quantity of aluminium, rod iron, ram and this three's of aluminum pipe structure has formed the dynamic object of reference of ram.Therefore, this structure makes measurement mechanism read the ram thermal stretching dynamic value embodying with physical state, only the actual condition value of instant ram thermal stretching need be passed to machine tool control system, contrast with ram initial value, save the conversion of difference or the comparison of aluminum pipe and steel ram or rod iron thermal stretching of invar, two kinds of material thermal stretching amounts of ram steel while measurement, avoid error, measure the data of the ram thermal stretching of getting more conscientiously precisely, machine tool control system is improved and revise the degree of accuracy of ram point of a knife.This is the difference in the design's theory just, it not the absolute value consideration taking invar theory as zero degree, but make the dynamic object of reference-rod iron end extensible extent under the direct reading operation state of measurement mechanism with described structure, be the actual amount of ram thermal stretching, thereby realize ram object of reference and no longer adopt expensive mark post invar, device fabrication cost is significantly reduced.

Brief description of the drawings

Fig. 1 measures the apparatus structure schematic diagram of ram thermal deformation;

Fig. 2 is the schematic diagram of Fig. 1 ram thermal deformation measurement device.

Detailed description of the invention

The design measures the device of ram thermal deformation, the technical measures that substitute zero degree invar are: referring to Fig. 1, ram housing, aluminum pipe, rod iron three are selected to equal length L, ram housing axial drilling, aluminum pipe, rod iron are installed in hole, setting ram front end is that positive direction, ram rear end are negative direction, it is characterized in that ram housing 1 and leading screw group 7 binding sites are in fixing ram rear end, and ram housing 1 is heated can only be extended to ram front end; Again aluminum pipe fixture 6 and the rear client link of aluminum pipe 3 are passed through in ram housing 1 rear end, aluminum pipe 3 is heated can only be extended to ram front end; Aluminum pipe 3 front ends and rod iron 4 front ends connect at aluminum pipe and rod iron fixture 2 places, after the rod iron 4 that makes to connect with aluminum pipe 3 is heated, produces oppositely and extend.Rod iron 4 is identical with the material of ram housing 1, and identical in described structure to be subject to thermogenetic thermal change amount be both direction, and locus is equivalent to series connection, and thermal stretching amount is 1+1.The measurement mechanism 5 that is positioned at ram rear end is connected with rod iron 4 rear ends.

In order to monitor the thermal stretching variable quantity of ram, must give relative object of reference of ram and realize the measurement of ram thermal stretching variable.In order to reduce costs, utilizing the aluminothermy coefficient of expansion is 2 times of characteristics of steel, and as shown in Figure 2, the characteristic of metal material is to fix when material one end to principle, when its temperature changes, can extend to free end.The thermal coefficient of expansion (1/ DEG C) of steel: every intensification 1 is spent. unit rice 0.0000118, the thermal coefficient of expansion (1/ DEG C) of aluminium: every intensification 1 is spent. unit rice 0.0000236, when unit of the every variation of ram case temperature of steel, be now all positive direction aluminum pipe and have more a unit 0.0000118 than ram.By client link before aluminum pipe front end and rod iron, make rod iron taken away 0.0000236 by aluminum pipe to positive direction, and rod iron free end extends 0.0000118 to the ram rear end of negative direction, on space, unit sum of rod iron and ram thermal stretching just equates with the thermal stretching amount of aluminum pipe, ram, aluminum pipe, rod iron three has just in time been combined into the object of reference of ram heat displacement amount, at this moment the rod iron being connected with measurement mechanism just occurs, the displacement of negative direction is the thermal stretching state of ram just, the numerical value ram heat displacement amount just that at this moment measurement mechanism of rod iron rear end collects, after passing to machine tool control system, be just to provide the numerical value that need to revise ram point of a knife.

Claims (1)

1. measure the device of ram thermal stretching for one kind, setting ram front end is positive direction, ram rear end is negative direction, ram housing axial drilling, it is characterized in that: get aluminum pipe (3), rod iron (4) and ram housing (1) equal length, in ram housing (1) axial hole, aluminum pipe (3) is installed, rod iron (4), ram housing (1) and leading screw group binding site (7) are in the fixing rear end of ram, again by client link after ram housing (1) rear end and aluminum pipe (3), aluminum pipe (3) front end and rod iron (4) front end are located to connect at aluminum pipe and rod iron fixture (2), rod iron (4) rear end is connected with measurement mechanism (5).

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