JPS5854951B2 - Jet injection grinding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a jet injection grinding method that solves the problem of reduced product accuracy due to escape of the object to be ground (work).

Grinding involves complex processing phenomena and theoretical understanding is slow, so the ``hunch'' of skilled workers on site plays a large role.

However, recently, the demand for engineering pursuits and higher precision and efficiency has increased rapidly, and theoretical studies and new technology development are being actively carried out from various fields.

One of the new technologies is the jet injection grinding method.

This technology sprays grinding fluid at high pressure to actively remove grinding heat, which is an impediment to increasing the efficiency of grinding processes.
It can be expected to have effects such as preventing reduction in dimensional accuracy due to grinding heat and extending the life of the grinding wheel.

However, various problems remain in practical application, one of which is the problem of reduced product accuracy due to workpiece escape during jet impact.

This will be explained in detail below with reference to the drawings.

In Fig. 1, 1 is a nozzle, 2 is a grinding wheel, and 3 is a workpiece that comes into contact with the grinding wheel 2.The contact surface or grinding surface (the grinding point is also a grinding surface from a microscopic point of view) has a thickness provided in the nozzle 1. Grinding fluid is injected from a slit with a diameter of 1 and a width of m.

By the way, since this grinding fluid is injected at a high pressure of 1 kg/i or more, a force F. that separates the grindstone 2 and the work 3 from each other is generated on the work 3 or the grindstone 2.

If the rigidity around the workpiece 3 and the two axes of the grindstone is K, and the grinding back force is Fr, then the escape amount d of the workpiece 3 is dwj(F +F・)/ in the jet injection grinding method, and The relief amount increases compared to the relief amount dwn=Fr/K in the normal liquid injection grinding method.

This phenomenon of escape has a negative effect on dimensional accuracy, but especially in traverse grinding (grinding in which feed is applied in the direction of the grinding wheel axis), as shown in Figure 2A, the grinding wheel 2 at the end of the workpiece 3 is Because it is necessary to grind workpiece 3 again after missing about % of the width, in other words, the second
As shown in the figure, since the amount of clearance is different, the grinding surface becomes convex in the center and the dimensional accuracy decreases (actually, the workpiece moves in the direction of the grinding wheel axis, but for the sake of explanation here, we will move the grinding wheel. ).

In order to prevent this decrease as much as possible, generally no cut is made at the end of grinding, and only the relief amount of the workpiece 3 is removed.

That is, grinding is performed until dw=O→F,=0, to obtain predetermined dimensional accuracy and surface roughness.

This is called spark out, but in the jet injection grinding method, even if the Fr is mainly 0, there is a difference in q between the end part -Am and part 4, so only a finished surface of 3 with a central convexity can be obtained. do not have.

If the pressure of the jet is lowered to prevent this, a problem arises in that the effect of the jet is reduced.

This invention was made to improve the above situation.
The purpose of the present invention is to provide a jet liquid injection grinding method that can prevent a decrease in dimensional accuracy due to workpiece escape and can fully demonstrate the effects of jet liquid injection.

The jet liquid injection grinding method of the present invention is characterized in that liquid is poured into the leading portion where the grinding surface is to be ground in the width direction of the grinding wheel.

For example, in finishing traverse grinding, as shown in Figure 2A, the feed amount S of the grindstone 2 per revolution of the workpiece 3 is generally around H in the grindstone, and the
The portion of the workpiece 3 corresponding to the amount of feed of the grindstone 2 per rotation (hereinafter referred to as the leading portion) has the highest load, and the rest only scratches the grinding marks on the leading portion.

Therefore, the part most in need of liquid injection is this leading part.

Therefore, in the present invention, the liquid is injected only to the leading part, thereby fully utilizing the effect of the jet flow, and reducing Fj to prevent deterioration in the shape and precision of the finished surface.

Moreover, this method can also distantly reduce the flow rate as a secondary effect.

Further, the present invention will be explained in detail based on examples.

FIG. 3 shows an example of the nozzle structure, in which a spacer 1b is placed on the nozzle body 1a, and a nozzle lid 1c is bolted.

In this way, a slit having a thickness l and a width m equal to the thickness of the spacer 1b is formed.

In addition, in order to adjust the flow of the grinding fluid, a preload chamber 5 and a land 1d are provided, and the land 1d is particularly made sufficiently smooth to have a surface roughness of 1 μm or less.

Now, the grinding fluid pressurized by the pump is sent to nozzle 1 from direction A.
It passes through the pre-pressure chamber 5, is ejected from the slit in the direction B, and is blown onto the grinding surface.

At this time, if the slit width m is changed, how will the removal effect of grinding heat (the criterion is grinding burn-out) change, how will the force Fj that separates the workpiece 3 and the grinding wheel 2 change, and how will the shape accuracy change? We have measured and compared the results with the conventional method and will show them here.

As is clear from the table, if the grinding fluid is injected only into the leading part of the grinding wheel, where the load is high (of course, some grinding fluid will also get around to other parts), the effect of removing grinding heat will be increased by injecting the entire surface of the grinding wheel. becomes the same, Fj decreases to H, and the shape accuracy improves significantly.

By the way, at the end of the workpiece 3, as shown in FIG. 2, it is removed by about % of the width of the grindstone 2.

Therefore, when traversing to the left as shown in FIG.
If the grinding wheel deviates from the workpiece 3, nozzle 1 is fixed to inject the grinding fluid into the EFGH section, and when the grinding wheel deviates from the workpiece 3 by about %, move nozzle 1 to the right and move the nozzle 1 to the IJKL, which is the leading part in the case of rightward traverse. You just need to set it so that the grinding fluid can be injected into the part.

As is clear from the above, the jet liquid injection grinding method of the present invention injects liquid into the leading part where the grinding surface is ground in the width direction of the grinding wheel. , it is possible to prevent a decrease in dimensional accuracy due to workpiece escape.

[Brief explanation of the drawing]

FIG. 1 is a schematic process diagram of the jet liquid injection grinding method, and FIG. FIG. 3 is an exploded perspective view of a nozzle used in one embodiment of the present invention, and FIG. 4 is an explanatory diagram showing a method of injecting grinding fluid in the same embodiment. 1...Nozzle 2...Whetstone, 3...Workpiece.

Claims (1)

[Claims] 1. In a jet injection grinding method in which grinding is performed by spraying a grinding fluid onto a grinding surface, the jet injection is characterized in that the liquid is injected into a part of the leading part that grinds the grinding surface in the width direction of the grinding wheel. Grinding method.