JPS5848302B2 - Control method for outer diameter machining of workpiece - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for controlling the outer diameter machining size of a workpiece.

Generally, when machining a circular workpiece, as shown in FIGS. 1 to 3, the workpiece 1 is placed on two shoes 2 and 3, the back surface is pressed against the packing plate 4, and the packing plate 4 is placed in an appropriate position. The workpiece 1 is rotated by a suitable means.
A method is adopted in which the outer diameter surface is ground using a grinding wheel 5.

In this case, the shoes 2 and 3 are often floating shoes that can rotate within a certain angle range around one point.

The reason for this is that it is known from experience that if the workpiece 1 is ground with both shoes 2 and 3 completely set, the Sanada cold after machining of the outer peripheral surface of the workpiece 1 is not good. be.

The method that is most commonly put into practical use in the field is to use a completely fixed shoe 2, which is closer to the grinding wheel 5, and a floating shoe 3, which is farther from the grinding wheel 5. There are two types of shoe 3 shapes.

The first method, as shown in FIG. 4, is a floating shoe in the shape of a square, in which the shoe 3 contacts the workpiece 1 at two points.

The second method is to match the curvature of the floating shoe 3 to the curvature of the workpiece 1, as shown in FIG.

Then, process the workpiece 1 in the state shown in FIG. 4 or 5,
If it is necessary to align the dimensions of the IAlff surface of workpiece 1, monitor the dimensions of workpiece 1 with an electric micrometer or other suitable detector installed separately during machining, and grind when the dimensions reach a predetermined value. The cutting of the grindstone 5 is stopped and the grinding wheel 5 is moved backward.

In this case, the diameter is measured by placing the detector at the bottom 6 of the workpiece 1, the left side 7 of the workpiece 1, or directly applying it to the top 8 and bottom 6 of the workpiece 1. .

However, this method has the following drawbacks.

That is, first, contact traces by the detectors 6, 7, or 8 are left on the surface of the workpiece 1.

Second, the tip of the detector 6, γ or 8 will wear out, so when machining a large number of workpieces, the dimensional signal of the detector 6, 7 or 8 will change when the stylus 6, 7 or 8 is worn. Since it differs from the dimension signal of , correction is required.

Thirdly, since the detector 6, γ or 8 is in the immediate vicinity of the workpiece 1, the abrasive scum generated by the grinding process or the coolant applied to the workpiece 1 may be transferred to the stylus and fixed part of the detector 6, 7 or 8. The mechanical movement of the stylus may be impaired.
Furthermore, it becomes a factor that generates noise in electrical signals.

Fourthly, since the detectors 6, 7 or 8 are in the immediate vicinity of the workpiece 1, loading the workpiece 1 onto the shoes 2, 3 and
Or when unloading the workpiece 1 from above the shoes 2, 3, the workpiece 1 impacts the detector 6, 7 or 8,
Accidents may occur where the stylus is damaged or bent.

Incidentally, if a non-contact type detector is used instead of the electric micrometer as the detector 6, 7 or 8, the first to third disadvantages can be solved, but in reality, it is used for polishing scum and coolant. I can't do that.

This invention was developed in view of the above-mentioned drawbacks of the conventional methods.Especially in the case of outer diameter machining of a workpiece using a floating shoe type, the shoe follows the change in the curvature of the outer diameter of the workpiece. The present invention aims to provide a method for controlling the machining dimensions of the outer diameter of a workpiece by detecting the minute rotational change amount X of the floating shoe and converting this into the change amount Y of the outer diameter dimension of the workpiece. be.

The structure of the present invention will be explained below according to the embodiment shown in FIG.

In FIG. 6, 2 is a fixed shoe, and 3 is a floating shoe that can rotate around 03.

It is also assumed that the shoe 3 is v-shaped and two points are in contact with the workpiece 1.

The orthogonal coordinates passing through the center 01 of the workpiece 1 are conveniently named the XX axis and the YY axis.

Workpiece 1 is constantly pressed against shoes 2 and 3 by the following three forces:

That is, when there is a component in which the YY axis is directed toward the center of gravity of the earth, it is pressed by the weight of the workpiece 1.

As shown in FIG. 3, the center 01 of the workpiece 1 is eccentric to the center 04 of the packing plate 4.
are arranged so that the packing plate 4 presses the workpiece 1 against the shoes 2 and 3 with a pressing force.

Alternatively, in the case of a structure in which magnetism is used as means for pressing the workpiece 1 against the packing plate 4 and the magnetic flux flows also to the shoes 2 and 3, the workpiece 1 is pressed by the magnetic attraction force acting between the shoes 2 and 3.

Therefore, the workpiece 1 is always pressed against the shoes 2 and 3, and when the outer radius r of the workpiece 1 becomes r and the workpiece 1 comes to the position 1', the floating shoes **1 of 3 are 2 with 03 as the center.
It rotates so that the point hits workpiece 1 or 1'.

On the other hand, a separately installed detector 9 is exposed to the shoe 3 to measure rotational changes of the shoe 3.

That is, the outer radius r of the workpiece 1 becomes r', the workpiece 1 is at the position 1', and the center of 1' is 0. As a result, the shoe 3 is tilted by an angle α relative to 03, and the shoe 3 is tilted to 3. Let's calculate what value α will be when this happens.

Here, it is assumed that the grinding wheel 5 grinds the workpiece 1 from the right side.

In this case, the positions of shoes 2 and 3 with respect to workpiece 1 actually vary, but here shoe 2 is located 07 below from the XX axis relative to 01, while shoe 3 is located at an angle from the XX axis relative to 0. Cold θ: Lower.

θ, is 30° to 600°, and θ2 is approximately 0° to 45°, which is practically used.

As an example, let θ1 be fixed at 45°, and on the other hand, if θ2 is bald, θ2
-0° (0) θ2=15°e) θ2=30°
(d) Let's consider four types of θ2-45°.

FIG. 6 shows the case of the f-blade, that is, θ2=30°.

Further, the V angle of the ■-shape of the shoe 3 may be any value as long as it is 180 degrees or less, but 150 degrees, which is often used, is used for convenience.

The length of the line connecting 0103 is r + L The length of the line connecting O103 is r + L Let the distance between 0 and 01 be l.

If the angle between 0.03 and the XX axis is β, the following four formulas hold mechanically.

becomes.

For the case of L=10M, the outer radius of workpiece 1 is r250
Calculate α for the three types of 7ta, 25th grade, and 5th grade and use detector 9
The amount of displacement detected by is as follows.

First, if the contact point of the tip of the stylus of the detector 9 with the shoe 3 is 04, and the detector 9 is placed parallel to 0 and 03 as shown in Fig. 6, and 0304 is the length R, then , α is expressed in radians, the amount of change in 04 measured by the detector 9 y=Rα (6) and the amount of dimensional change in the workpiece 1 X""r r'... ...The relationship with (7) is R21
When it is 0 wIt, it becomes as shown in Figure 1, and the following two facts can be understood.

First, the relationship between y and X is almost linearly proportional.

And it can be proved mathematically as follows that the relationship between y and X is almost linearly proportional.

From Equations (5) and (6X7), in Equation (9), r+L is overwhelmingly larger than machining allowance x=rr', so (9) becomes dy 1° 3° 4Roo) dx r+L and is made into a constant.

dy When the machining allowance is small compared to r, - is close to a constant value, and dx The relationship between y and X can be said to be linear proportionality.

Second, the size of y can be about the same as the value of x.

The size of y depends on R, but R = 10 adopted in Figure 7
The value of ff is large enough to be used practically.

Figure 7 shows the case where θ2-300, but θ210°
Both r-25 for 15° and 45°, R=1
0, L2 and 10, y and X are calculated as shown in Figure 8, and from this (1) No matter what angle θ2 is, y and X are linearly proportional.

(2) The thicker θ2, the smaller the value of V=Rα, but if the size of R is appropriately selected, a practically necessary value of y can be obtained.

Although it is theoretically possible to search for θ2 of 600 or more, in that case, it is not practical because there is a great danger that the workpiece 1 will jump out to the left if it is held from the shoe 3 due to the grinding force that the grindstone 5 applies to the workpiece 1. Therefore, it is not calculated.

In addition, here, the angle θ1 between the shoe 2 and the XX axis is fixed at 300, but in reality, the shoes 2 and 3 can be used as dimensional changes of the workpiece 1 as changes in α within a range that does not cause trouble during grinding. If it is set at a position where it becomes large, changes in the dimensions of the workpiece 1 can be detected by α.

Also, since both shoes 2 and 3 are floating shoes, dimensional changes in the workpiece 1 can be detected by applying a detector to either of the shoes 2 or 3.

As explained above, in the outer diameter machining of a workpiece using a floating shoe, the outer diameter of the workpiece gradually becomes smaller as the machining progresses, and the floating shoe follows the change in curvature. Utilizing this phenomenon, the minute rotational change amount X of the floating shoe is detected with a detector such as an electric micrometer, and the detected change amount X is converted into the outer diameter dimension change amount Y of the workpiece. The feature is a method for controlling the outer diameter machining dimensions of a workpiece, and therefore, when it is necessary to detect changes in the outer diameter dimension of the workpiece during machining, it is possible to detect the dimensions of the workpiece without directly applying the detector to the workpiece. If we use the fact that the floating shoe rotates due to the change and adopt a method of detecting dimensional changes by applying a detector to the floating shoe, there will be no contact traces of the detector on the workpiece, and the history will be reduced. Since the detector does not come into contact with rotating objects, the dimensional signal does not require correction even if many workpieces are machined without wear.

Furthermore, since the detector can be moved far away from the workpiece, it is not exposed to polishing scum or clumps, so mechanical trouble or electrical noise does not occur to the detector.

Furthermore, since the detector can be placed far from the workpiece, it is not exposed to polishing scum or coolant, making it possible to use a non-contact type detector.

Furthermore, there is no danger of the workpiece hitting the detector and damaging the detector during loading and unloading of the workpiece.

Furthermore, if the values of R, θ, L, etc. are appropriately selected, there are advantages such as detecting the dimensional change of the workpiece to be larger than the actual value or smaller than the actual value.

[Brief explanation of drawings]

Figures 1 to 3 are drawings showing the conventional shoe support system;
4 and 5 are drawings showing a conventional shoe support method and a method for detecting workpiece dimensions, respectively, FIG. 6 is a drawing showing a method for controlling workpiece dimensions by the method according to the present invention, and FIG. 8 and 8 are drawings each numerically representing a specific example in which the present invention is applied. 1... Workpiece, 2, 3... Shoe, 5
...Grinding wheel, 9...Detector.

Claims (1)

[Claims] 1. When machining the outer diameter of a workpiece using a floating shoe, the outer diameter of the workpiece gradually becomes smaller as the machining progresses, and the floating shoe follows the change in curvature. The outer diameter of a workpiece, characterized in that the minute rotational change amount X of the shoe is detected by a detector such as an electric micrometer, and the detected change amount X is converted into the outer diameter dimension change amount Y of the workpiece. Machining dimension control method.