JPH0829353B2 - Shaft bend correction method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending correction method for automatically correcting the bending of a shaft.

2. Description of the Related Art For example, as a method for correcting the bend of a shaft of this type, there is a method shown in FIGS.
45224).

In this configuration, a pressing mechanism 3 is arranged above a shaft W supported at both ends by a headstock 1 and a tailstock 2, while a plurality of measuring mechanisms 4 to 11 for measuring the bending of the shaft W are arranged below the shaft W. A plurality of pedestals 12 to 19 for supporting the shaft W are arranged in parallel along the longitudinal direction of the shaft W. The shaft W can be rotated by the servo motor 20, and the rotation angle position thereof is detected by the pulse generator 21. Further, the pressurizing mechanism 3 is provided with a ram 22 that can be raised and lowered, and the amount of pushing is controlled by receiving a command from the control device 23.

On the other hand, the plurality of pedestals 12 to 19 are placed on the table 24, and the pressing mechanism 3 can be opposed to any of the pedestals 12 to 19 by horizontally moving the table 24.

Then, by rotating the shaft W once to operate the measuring mechanisms 4 to 11, the deflection Ti at each point of the shaft W is changed.
Since r can be measured, the pressurizing mechanism 3 and the cradle 1
2 to 19 give curvature displacements to the points A to H of the shaft W to correct the bending.

That is, FIG. 4 (A) is a conceptual diagram of the measured value of the shake of the shaft W, and the arrows indicate the direction and the size of the shake. Since the bending allowance of the shaft W is defined with reference to the circumferences of both ends of the shaft W, the measured values of the remaining measuring mechanisms 5 to 10 are used as a reference even at the time of measurement. Is corrected by calculation processing inside the control device 23. FIG. 4 (B) shows the magnitude of the shake that has been calculated and corrected, that is, the magnitude of the bending amount at each of the points A to H.

The bending correction work will be described by taking the point D as an example. _Xd is the local curvature of the point D with respect to the points C and E, and the curvature _Xd is the measurement mechanism 6,7. , 8 calculated values. The curvature displacement amount S _d required to make the curvature X _{d 1} zero is calculated from the curvature X _{d 1} , and the ram is moved until the curvature displacement amount at the point D becomes S _d + α (α is the spring back amount).
Give a push command to 22.

Then, by applying the above method to each point other than the point D and performing the correction, the bending of the entire shaft W can be corrected to be equal to or less than the allowable value.

By the way, in the above correction method, since it is premised that the partial curvature of each point falls within a predetermined allowable limit, the curvature of each point is temporarily within the allowable width. However, the bending amount of the entire shaft does not always fall within the allowable limit. For example, as shown in FIG. 5, even if the local curvature of each point A to H of the corrected shaft W is within the allowable limit, the measurement error of each point A to H is accumulated. , Especially about point D, Shaft W
The amount of bending with reference to both ends of may exceed the allowable limit.

Therefore, conventionally, after the primary correction as described above, the bending amount of each point A to H is measured again as shown in FIG. 5, and the point having the largest bending amount, that is, the point D in the center is measured at both ends of the shaft W. It has been attempted to modify again so that the bending amount becomes zero with reference to. That is, the broken line J in FIG.
By correcting the pressure until the solid line K, each point A ~
The local curvature of H is within the allowable limit, and the shaft W
The amount of bending as a whole falls within a predetermined allowable limit.

Problems to be Solved by the Invention When the final correction as described above is performed in the apparatus shown in FIG. 3, the shaft W is compared with the case of the primary correction.
Since the amount of correction displacement to be applied to the shaft is large, the amount of rebound at both ends of the shaft is large, and the measuring mechanisms 4 and 11 at both ends of the shaft W cannot follow this repulsion, and as a result, the feed back amount of the pressing mechanism 3 is reduced. You may lose control. This is because the measurement stroke of each of the measuring mechanisms 4 and 11 cannot be increased so much due to the restriction on the accuracy of the measuring mechanisms 4 and 11.

Means for Solving Problems The present invention provides a correction method that solves the above problems, and as shown in the embodiments, a pressurizing mechanism is provided above a shaft whose both ends are supported. On the other hand, a plurality of measuring mechanisms for measuring the bending of the shaft and a plurality of pedestals for supporting the shaft are arranged below the shaft along the longitudinal direction of the shaft, and measurement data of each measuring mechanism is provided. A method of correcting the bending of the entire shaft with reference to both ends of the shaft by giving a predetermined pushing amount command to the pressing mechanism based on Then, at the measurement point corresponding to each measurement mechanism, the step of measuring the bending amount at each measurement point when the outer peripheral surfaces of both ends of the shaft are used as a reference, and the measurement data at each measurement point are also included. And the maximum bending position and direction of the shaft are specified, and the maximum bending position and direction are determined on the pressing axis of the pressing mechanism, and a predetermined calculation is performed based on the bending amount of the maximum bending position. And calculating the pushing amount for the maximum bending position of the pressurizing mechanism required to make the bending amount at the maximum bending position zero.

The pressing amount of the pressurizing mechanism is a value of the local curvature of the maximum bending position, which is represented as a difference in the bending amount between the maximum bending position and the measurement points on both sides thereof, and the local curvature at the maximum bending position. When the maximum curvature position is set to zero, it is still due to the local curvature of the measurement points on both sides of the maximum bending position, which is represented as the difference between the measurement points on both sides of the maximum bending position and the measurement points on both sides of the maximum bending position. The feature is that it is calculated as a sum with the value of the bending amount that the maximum bending position has.

Embodiment FIG. 1 and FIG. 2 are views showing an embodiment of the present invention, and FIG. 1 shows the bending state of the shaft W shown in FIG. 3 before and after final correction. . However, FIG. 1 exemplifies the case where local curvatures remain at the three points C, D, and E.

First, in the step shown in FIG. 2, the shaft W after the primary correction is rotated once to measure the bends X _c , X _d , and X _e of the points C, D, and E by the measuring devices 6, 7, and 8. Bend of each point here X _c , X _d , X _e
Is the deflection T of each point C, D, E with reference to both ends of the shaft W
It is half the value of ir (see Fig. 4). Then, at the step, the point with the largest bend, that is, point D in FIG.
The entire table 24 is horizontally moved so as to be located right below 22, and in the step, the rotational direction is indexed so that the convex portion having the largest curvature among the points D faces upward.

Here, c ₁ , d ₁ , and e 1 in FIG. ₁ are the local curvatures of the respective points with reference to the measurement points on both sides, respectively.
For example, d ₁ of the point D is a local curvature at the point D when the points C and E on both sides are used as a reference. Further, assuming that the local curvature d ₁ at the point D is corrected to be zero, c ₂ and e ₂ are the values when the measurement points on both sides of the points C and E are used as a reference. Is the local curvature of points C and E, and d
₂ is still due to the local curvatures c ₂ and e ₂ at the points C and E, assuming that the local curvature d ₁ at the point D is corrected to be zero as described above. Is the amount of bending that point D will have. Then, the respective local curvatures and bending amounts are derived by the following equations.

Since it is considered that the curvatures of C point and E point do not change before and after the modification, c ₂ ≈ c ₁ …… (v) e ₂ ≈ e ₁ …… (vi) Therefore, in order to set X _d to zero, In this case, the curvature displacement may be given to the point D as a correction amount by d ₁ + d ₂ .

Therefore, the value of d ₁ + d ₂ is calculated.

First, substituting equations (v) and (vi) into equation (iv) Substituting equations (i) and (ii) into equation (vii) From the above, from equation (iii) and equation (viii) Becomes

However, coefficient multiplication to the value of X _d of the above formula {(l _{8
-L 7) (l 7 -l 6} ) · l 0} / {(l 8 -l 6) (l 0 -l 7) ·
l ₇ } is determined by the measurement position of the shaft W, but it is set as a parameter because there is some error in practice.

In the step of FIG. 2, the bending amount _Xd of the point D, which is the maximum bending position, is stored, and the value of this _Xd is multiplied by the above coefficient to obtain the correction amount ΔC _d .

Furthermore, performs operations comprising S _i = f _i · ΔC _d based on the correction amount [Delta] C _d to be plus a spring-back amount of the shaft W in correction amount [Delta] C _d in step, the ram relative to the point D 22
Find the indentation amount S _i to be given by. Then, the ram 22 of the pressing mechanism 3 pushes the point D in step.
In this case, the value of ΔC _{d and} the value of S _i change every moment according to the pushing operation.

In the step, it is judged whether or not the value of ΔC _d becomes less than or equal to the allowable value ε, and the steps are repeated until ΔC _d ≦ ε.

As a result, the bending state of the shaft W is point Am- in FIG.
When nOH is tied, the bending of the entire shaft W with respect to both ends of the shaft W is corrected so as to be within the allowable value.

EFFECTS OF THE INVENTION According to the present invention, the pushing amount with respect to the maximum bending position of the pressurizing mechanism necessary for making the bending amount at the maximum bending position of the shaft zero, the maximum bending position and the measurement points on both sides thereof are determined. When the value of the local curvature of the maximum bending position represented as the difference in the bending amount and the local curvature at the maximum bending position are set to zero, the measurement points on both sides of the maximum bending position and further on both sides thereof. Since it is calculated as a sum with the value of the bending amount that the maximum bending position still has due to the local curvature of the measurement points on both sides of the maximum bending position that is expressed as the difference from the measurement point, If the measurement mechanism at both ends of the shaft cannot follow, as described above, there will be no trouble, and the probability that the bend will fall within the allowable value will be significantly increased, and the correction efficiency will be improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the method of the present invention, FIG. 2 is the same flow chart, FIG. 3 is a structural explanatory view of a conventional bend correcting device, and FIGS. 4 (A) and 4 (B) are FIG. 5 is an explanatory view showing a bent state of a conventional shaft, and FIG. 5 is an explanatory diagram before and after the shaft is corrected. 1 ... Headstock, 2 ... Tailstock, 3 ...
Pressure mechanism, 4,5,6,7,8,9,10,11 …… Measurement mechanism, 12,13,14,
15,16,17,18,19 …… Cradle, 22 …… Lamb, W …… Shaft.

Claims (1)

[Claims] 1. A pressurizing mechanism is arranged above a shaft whose both ends are supported, while a plurality of measuring mechanisms for measuring bending of the shaft are provided below the shaft, and a plurality of pedestals supporting the shaft. Side by side along the longitudinal direction of the shaft,
This is a method of correcting the bending of the entire shaft with reference to both ends of the shaft by giving a predetermined pushing amount command to the pressing mechanism based on the measurement data of each measuring mechanism and performing a pressing operation. And rotating the shaft at least once, and measuring the amount of bending at each measurement point when the outer peripheral surface of both ends of the shaft is used as a reference at the measurement point corresponding to each measurement mechanism, and the measurement data at each measurement point The maximum bending position and the direction of the shaft are specified based on the above, and the maximum bending position and the direction are determined on the pressing axis of the pressing mechanism, and the predetermined bending amount is determined based on the bending amount of the maximum bending position. And a step of calculating a pushing amount with respect to the maximum bending position of the pressurizing mechanism necessary to make the bending amount at the maximum bending position zero, the pushing amount of the pressing mechanism is maximum When the local curvature at the maximum bending position and the local curvature at the maximum bending position, which is represented as the difference in the amount of bending between the bending position and the measurement points on both sides thereof, are zero, the maximum bending The value of the bending amount that the maximum bending position still has due to the local curvature of the measurement points on both sides of the maximum bending position, which is represented as the difference between the measurement points on both sides of the position and the measurement points on both sides of the position. A method for correcting shaft bending, which is calculated as the sum of