JP2538898B2 - Angular grinding depth of cut using a centerless grinding machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an angular grinding cutting method for simultaneously grinding an outer diameter of a shaft portion of a workpiece and a shoulder portion orthogonal thereto by a coreless grinding machine. Is.

[Conventional technology]

It is known to simultaneously perform angular grinding of an outer diameter of a shaft portion of a workpiece and a shoulder portion orthogonal thereto while applying a thrust to a workpiece by a feed angle and rotation of an adjusting grindstone using a centerless grinder. Is. For example, as shown in FIG. 5, in the case of a work piece 1 having a shaft portion 1a and a shoulder portion 1b orthogonal thereto, a conical grinding wheel 2 having an outer peripheral surface 2a and an end surface 2b orthogonal thereto is used. It can be used to give a notch in the direction of arrow P to angularly grind the outer diameter of the shaft part 1a of the workpiece and the shoulder part 1b at the same time (note that the above notch is relative and actually adjusted. Many of the grindstones perform a cutting operation.The adjustment grindstone has a feed angle, and the work piece receives a thrust force in the axial direction due to the rotation of the adjustment grindstone having the feed angle. Is the axial component of the frictional force that the workpiece receives from the adjusting grindstone.

In this case, when the length 1 of the shaft portion 1a of the workpiece is constant, the stopper 3 is installed opposite to the end surface 1c of the workpiece with a constant minute gap Δ ₂ between the shoulders of the workpiece. If the relationship between the minute gap Δ ₁ between the portion ₁ b and the end surface 2 b of the grinding wheel 2 and the above Δ ₂ is Δ ₂ −Δ ₁ = grinding margin, the end surface 1 c of the workpiece is
Sparking out (finishing of grinding) at the time when the wheel hits the stopper 3 makes it possible to accurately finish the perpendicularity of the shoulder portion 1b with respect to the shaft portion 1a.

[Problems to be solved by the invention]

As described above, when the length 1 of the shaft portion 1a of the workpiece is constant, the shoulder portion 1b of the workpiece can be accurately ground, but the length 1 of the shaft portion 1a of the workpiece is constant. If not,
With the configuration shown in FIG. 5, the spark-out time cannot be regulated, so that accurate angular grinding cannot be performed.

Therefore, when the length of the shaft of the workpiece is not constant, as shown in FIG. 6, the stopper 3 is installed close to the shoulder 1b of the workpiece, and the gap Δ between the shoulder 1b and the stopper 3 is increased. _By setting ₃ to about a few microns, the grinding depth per revolution of the workpiece is limited, which prevents the shoulder from being excessively ground and reduces the runout of the shoulder from the axis to a few microns or less. It can be held down.

Considering one revolution of the workpiece, the stopper 3 is in contact with the unground surface of the shoulder 1b of the workpiece 1, and the end surface 2b of the grinding wheel 2 grinds the unground surface by a dimension Δ ₃ . This operation is performed during one rotation of the workpiece, and this is continuously and repeatedly performed, so that metaphorically speaking, the shoulder portion of the workpiece is ground into a spiral surface having a pitch dimension Δ ₃ . If such spiral surface grinding is stopped midway, a step having a minute dimension Δ ₃ remains.

Therefore, the smaller the gap size Δ ₃ is, the higher precision the grinding finish becomes, and the larger the size Δ ₃ is, the lower the precision of the grinding finish is.

However, if the position of the stopper 3 is fixed irrespective of the grinding wheel as in the prior art, the gap dimension Δ ₃ increases as the grinding progresses. For example, in FIG. 6, when the stopper 3 is stopped and the grinding wheel 2 moves in the direction of the arrow P (ignoring the reduction due to abrasion of the grinding wheel), the clearance dimension Δ _{3 is} equal to the moving amount of the grinding wheel sin α. Will increase.

When the angular angle α is 10 ° and the grinding allowance is 0.1 mm, the increase amount of the gap size Δ ′ = 0.1 × sin10 ° ≈0.018, and Δ ₃ set to several microns increases by about 18 μm. Such an increase in the gap size Δ ₃ reduces the grinding accuracy of the shoulder portion.

The present invention solves the problems of the prior art as described above, and even in the case of a workpiece in which the length of the shaft part is not constant, the angular grinding cutting by the coreless grinding machine that can grind the shoulder part very accurately. The inclusion method is provided.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention fixedly sets a stopper located near the shoulder of the workpiece on the workpiece support table, and It is configured to be able to retreat in a direction away from the axis of the grindstone at a right angle, and the grinding grindstone and the adjusting grindstone are relatively brought close to each other in a state where the relative positional relationship between the stopper and the grindstone is kept constant. Cut and feed.

When the cutting feed approaches the end, the workpiece support is retracted, and the stopper is controlled to come into contact with the shoulder of the workpiece.

The above-mentioned “fixedly installed” means fixed during the grinding operation, and it is within the technical scope of the present invention even if it is movable for adjustment.

[Action]

Since the cutting is performed in a state where the relative positional relationship between the stopper and the grinding wheel is kept constant, the set gap Δ ₃ between the shoulder portion of the workpiece and the stopper remains unchanged, which allows relatively high precision grinding. At the time when the cutting is near the end, the workpiece support is retracted in the direction to separate it at right angles to the axis of the grinding wheel, and the stopper is lightly contacted with the shoulder of the workpiece. Highly accurate shoulder grinding can be performed.

〔Example〕

FIG. 1 is a plan view of a coreless grinding machine to which the present invention is applied, and FIG.
The figure is also a front view, and in order to facilitate understanding of the present invention, drive mechanisms and the like not directly related to the present invention are omitted. FIG. 3 is a partially enlarged view of FIG. 1, and FIG. 4 is a partially enlarged view of FIG.

As shown in these figures, in this embodiment, the grinding wheel 2 is supported on the base frame 5 so as to be rotationally driven at a fixed position, and the grinding wheel is orthogonal to the outer peripheral surface 2a. And a conical shape having an end surface 2b that is formed. Reference numeral 4 denotes an adjusting grindstone, which is supported by the upper slide 6 so as to be rotationally driven, and which is the upper slide 6
Is supported on the lower slide 7 so that it can be advanced (approaching the grinding wheel) or retracted in the direction A having a desired angular angle α. Therefore, in the case of this embodiment,
The upper slide 6 is configured to make a cut by advancing (+) in the A direction.

In the present invention, the workpiece support base 8 is fixed on the lower slide 7, and the lower slide advances in the direction B perpendicular to the axis of the grinding wheel 2 (approaches the grinding wheel), Alternatively, it is supported on the base frame 5 so that it can be retracted. Then, the receiving blade 9 of the workpiece is fixed to the workpiece support base 8, and the stopper 3 facing the shoulder portion 1b of the workpiece 1 is fixed to the receiving blade 9 with a gap Δ ₃ of several microns. .

And in the present invention, the grinding wheel 2 and the stopper 3
In a state where the relative positional relationship between the upper slide 6 and the lower slide 7 is kept constant, that is, the upper slide 6 is advanced in the (+) direction of the arrow A to make a cut. By doing so, the shaft portion 1a and the shoulder portion 1b of the workpiece are simultaneously ground by the outer peripheral surface 2a and the end surface 2b of the grinding wheel, and the relative positional relationship between the grinding wheel 2 and the stopper 3 is constant. From
Since Δ ₃ is constant, relatively high precision grinding can be performed.

Thus, when the grinding cut is near the end, the lower slide 7 is slightly retracted in the (-) direction of arrow B. In this case (see FIG. 1), the speed (vector amount) with which the adjusting grindstone 4 cuts into the workpiece 1 is V _i, and the forward speed (vector amount) of the lower slide 7 with respect to the base 5 is V _B , Assuming that the forward speed (vector amount) of the lower slide 6 with respect to the lower slide 7 is V _A , V _i = V _A + V _B.

Assuming that the retracting distance in the direction of arrow B is L _B (scalar amount) (see FIG. 3), the stopper 3 retracts in the direction of arrow B relative to the grinding wheel 2 by a distance L _B (lower right direction in the figure, −
In the B direction), the gap dimension Δ ₃ decreases by L _B sin α.

Therefore, when retreating by L _B = Δ ₃ / sin α, the gap size becomes zero.

In this case, the gap dimension Δ ₃ does not instantly become zero, but gradually decreases as the lower slide 7 retreats in the (−) direction of the arrow B, and then becomes zero.

As described above, the shoulder portion 1b of the work piece 1 has the pitch dimension Δ.
Since it is ground into a spiral surface of ₃ , the pitch of the spiral surface gradually decreases as the gap size Δ ₃ gradually decreases.

Then, when the gap size Δ ₃ becomes zero, the grinding of the shoulder portion 1b sparks out. In this way, the shoulder 1b is finished with high accuracy so as to form a right angle with respect to the axis of the workpiece.

The initial gap dimension Δ ₃ is now 0.003 mm (3 microns)
Then, when the trial calculation is performed for the case where the angular angle α is 10 °,
The arrow B necessary for zeroing the above gap dimension Δ ₃
The receding distance LB in the direction is about 0.017 mm (17 microns).

〔The invention's effect〕

As mentioned above, according to the present invention, the length l of the workpiece is
Even if is not constant, there is an effect that angular grinding of a workpiece can be performed with extremely high accuracy.

[Brief description of drawings]

1 is a plan view of a coreless grinding machine to which the present invention is applied, FIG. 2 is a front view of the same, FIG. 3 is an enlarged view of a part of FIG. 1, and FIG.
The drawing is an enlarged view of a part of FIG. FIG. 5 is an explanatory diagram of coreless angular grinding when the length of the workpiece is constant, and FIG. 6 is an explanatory diagram of coreless angular grinding when the length of the workpiece is not constant. 1a …… Shaft of work piece, 1b …… Shoulder of work piece, 2 …… Grinding grindstone, 3 …… Stopper, 4 …… Adjusting grindstone, 5 …… Base, 6 …… Upper slide, 7 …… Lower part Slide, 8 ……
Workpiece support, 9 ... Receiving blade.

Claims (1)

(57) [Claims] 1. In angular grinding by a coreless grinder in which an outer diameter of a shaft portion of a workpiece and a shoulder portion orthogonal to the shaft portion are simultaneously ground by one grinding wheel, the workpiece is positioned close to the shoulder portion of the workpiece. The stopper is fixedly installed on the workpiece support base, and the workpiece support base is configured so as to be retractable in a direction in which the workpiece support base is separated at right angles to the axis of the grinding wheel. Perform cutting feed in a state where the relative positional relationship with the grindstone is kept constant, and when the above-mentioned cutting feed approaches the end, retract the workpiece support table to bring the stopper into contact with the shoulder of the workpiece. Angular grinding cutting method with a coreless grinding machine.