JP2000108032A - Grinding machine and grinding fluid supplying method in grinding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a machining affected layer and to decrease the supplying amount of grinding fluid when grinding is performed by moving a grinding wheel according to the angular phase of a work piece to be eccentrically rotated. SOLUTION: A right-angled nozzle 20 for supplying grinding fluid to the machining front surface of a grinding wheel G at right angles and a straight nozzle 10 for supplying grinding fluid to a grinding point K are provided. The flow velocity of grinding fluid from the right-angled nozzle 20 is set to 5.0 m/s or more, and the flow rate of grinding fluid from the straight nozzle 1 is set in the range of 25 to 50 lit/min. Therefore, efficient cooling is made possible by the small amount of grinding fluid, and a machining affected layer can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding machine for grinding a workpiece, for example, a pin portion of a crankshaft, having a processing portion at a position eccentric to a rotation center axis, and a grinding fluid supply method therefor.

[0002]

2. Description of the Related Art When grinding a conventional technique, particularly when grinding a pin portion of a crankshaft, a pin portion to be machined by an eccentric chuck and a phase indexing device provided at the tip of the spindle is set at the center of rotation of the spindle. It was indexed, gripped, and ground. However, this method requires a mechanism such as an eccentric chuck and a phase indexing device, and requires indexing for each phase angle of the pin portion, which is very inconvenient, increases cost and increases cycle time. Was a factor.

Therefore, as shown in FIG. 6, there is known a method of grinding a crankpin in which a crankshaft is rotated about a journal, and a grinding wheel G is moved forward and backward in accordance with a pin part which performs eccentric movement. I have. In the second conventional grinding method, since the pin portion performs eccentric motion according to the rotation angle phase, the grinding point K (the contact point between the grinding wheel and the pin portion) always moves.

A nozzle for supplying a grinding fluid to the grinding point K is provided with a grinding point K at a position where the angle phase of the pin portion P is 0 degree or 180 degrees as in the case of the conventional eccentric chuck.
Of the grinding fluid using one of the straight nozzle 10 (see (A)) directed toward the grinding wheel and the right-angle nozzle 20 (see (B)) for supplying the grinding fluid perpendicular to the surface of the grinding wheel G. It is carried out.

[0005]

Since the grinding point K moves as shown in FIG. 6 by the eccentric movement of the pin portion P, the grinding fluid is always supplied to the grinding point K in the fixed straight nozzle 10 or the right-angled nozzle 20. And the thickness of the damaged layer becomes large.

Since the affected layer must be removed at the time of fine grinding and fine grinding, if the thickness is large at the end of rough grinding, the allowance for fine grinding and fine grinding increases and it takes time. In particular, the thickness of the damaged layer becomes large at an angle phase of 90 degrees where the distance from the nozzle is longer than other angle phases and the grinding fluid is not directly supplied to the grinding point K. .

Therefore, in order to reduce the thickness of the deteriorated layer, that is, to increase the cooling effect, grinding burn has been prevented by supplying a large amount of grinding fluid of 100 liter / min or more. The thickness of the work-affected layer could not be reduced below a certain value. Therefore, the cycle time has to be sacrificed by lowering the grinding efficiency. In addition, the supply of a large amount of grinding fluid causes an increase in the size of the pump and the tank, which increases the installation space and increases the cost.

According to the present invention, when grinding a processing portion of a workpiece which is eccentrically moved, the grinding portion is efficiently cooled with a grinding fluid having a flow rate as small as possible, and further, the grinding burn is further reduced. It is the purpose.

[0009]

SUMMARY OF THE INVENTION A grinding machine according to the present invention includes a workpiece rotationally driven by a work spindle, and a reciprocation in a direction perpendicular to a rotation axis of the work spindle according to a rotation angle phase of the workpiece. In a grinding machine, comprising: a moving grindstone head, and a grindstone wheel rotatably supported by the grindstone head and performing a grinding process on the workpiece with the reciprocation of the grindstone head, wherein the grinding wheel and the workpiece A right-angled nozzle for supplying a grinding fluid from a direction orthogonal to a processing surface of a grinding wheel near an upstream side of a grinding point where the grinding wheel contacts, and a straight nozzle for supplying a grinding fluid to the grinding point, the grinding wheel table. It is provided so as to move forward and backward integrally.

The flow rate of the grinding fluid supplied from the right-angle nozzle may be 5.0 m / s or more, and the flow rate of the grinding fluid supplied from the straight nozzle may be in the range of 25 liter / min to 50 liter / min. . As a method of supplying a grinding fluid of this grinding machine, a crankshaft is rotationally driven around a journal by a work spindle, and a grinding wheel is moved forward and backward in a direction orthogonal to the work spindle in accordance with a rotation angle phase of the crankshaft. Thus, in the grinding fluid supply method in a grinding machine that performs grinding of the pin portion of the crankshaft that is eccentrically moved, the grinding fluid is orthogonal to the processing surface of the grinding wheel near the upstream side of the grinding point where the grinding wheel contacts the workpiece. When the grinding fluid is supplied at a flow rate of 5.0 m / s or more from a right-angled nozzle provided toward the direction of rotation, and the center axis of the pin portion is located on the same horizontal line as the rotation axis of the grinding wheel. 25 from the straight nozzle provided toward the grinding point
The grinding fluid is supplied at a flow rate of liter / min or more and 50 liter / min or less.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In an embodiment of the present invention, a grinding wheel mounted on a grinding wheel base 5 and rotated in the same direction as the crankshaft W with respect to a crankshaft W rotated by a work spindle (counterclockwise in FIG. 1). An example of crankpin grinding in which a grinding process is performed by G will be described, and a method of supplying a grinding fluid in the grinding and a grinding machine for performing the same will be described with reference to the drawings.

The shaft end of the crankshaft W is supported at the center or held by a chuck.
Is driven to rotate about the journal J by the work spindle which is rotated. Thereby, as shown in FIG.
Is eccentrically moved about the center of the journal J. The grinding wheel G is rotatably supported by a grinding wheel head 5, and the grinding wheel head 5 has a pin portion P that is eccentrically rotated by a work spindle.
By controlling the rotation of the motor 33 in accordance with the angular phase of the motor, the motor 33 is moved forward and backward in the horizontal X-axis direction.

The motors 35 and 33 are provided with encoders 36 and 34 for detecting the respective rotation angles. The motors 35 and 33 and the encoders 36 and 34 are connected to a numerical controller 40, respectively. By controlling the operations of the motors 35 and 33 synchronously by the numerical controller 40, the wheel head 5 is moved forward and backward in accordance with the angular phase of the crankshaft W, and the pin portion P is ground into a cylindrical shape.

The grinding wheel head 5 has a grinding wheel cover 3 for covering the grinding wheel G.
0 is provided, and the whetstone cover 30 has the pin portions P at positions where the phase angle of the pin portions P is 0 degree and 180 degrees.
Nozzle 10 for supplying a grinding fluid toward a grinding point K at which the grinding wheel G comes into contact with the grinding wheel G, and a perpendicular to the working surface of the grinding wheel G in the vicinity of the grinding point on the upstream side in the rotation direction of the grinding wheel G. A right-angle nozzle 20 for supplying a grinding fluid is provided. Pipes 11 and 21 are connected to the straight nozzle 10 and the right-angle nozzle 20 to supply the grinding fluid, respectively. These pipes 11 and 21 are installed on the grindstone cover 30 via the bracket B.

A grinding fluid supply device (not shown) is connected to the pipes 11 and 21. The grinding fluid supplied from the grinding fluid supply device is supplied to the grinding point and the grinding wheel G via the straight nozzle 10 and the right angle nozzle 20. Supplied to the surface. As a method of supplying the grinding fluid supplied from the straight nozzle 10 and the right-angled nozzle 20, the supply of the grinding fluid from the straight nozzle 10 has a flow rate of 50 L / min or less, preferably,
The range is from 25 liter / min to 50 liter / min.

The supply of the grinding fluid from the right-angled nozzle 20 is performed at a flow velocity of 5.0 m / s or more, preferably 5.0 to 7.7 m / s.
Range. As described above, since the supply method from the straight nozzle 10 and the right-angled nozzle 20 are different, the grinding fluid supply device connected to the nozzles 10 and 20 and supplying the grinding fluid may be provided individually for each of the nozzles 10 and 20. . In addition, using one grinding fluid supply device, each nozzle 1
By providing a valve between the nozzles 0 and 20, the flow rates and flow rates of the nozzles 10 and 20 may be changed. By doing so, the installation space of the pump can be reduced.

FIG. 2 shows a second conventional crankpin grinding method, that is, a method of grinding a crankpin by moving a grinding wheel G forward and backward in accordance with the angular phase of the eccentrically moved crankpin. 10 is a graph showing a change in the thickness of a damaged layer when rough grinding is performed by supplying a grinding liquid using only one of the nozzle 10 and the right-angled nozzle 12.

The thickness of the work-affected layer referred to here is the thickness of the surface layer where the work is damaged by the grinding heat and the chemical and physical properties of the metal structure such as hardness and residual stress have changed. In other words, it indicates the thickness whose properties have changed due to grinding burn. The measured value of the affected layer is determined by the position of the pin P where the grinding fluid is difficult to be supplied and the burn easily occurs, that is, the position where the pin P contacts the grinding wheel G when the angular phase of the pin P is 90 °. Things.

With the straight nozzle 10 alone, although the thickness of the affected layer gradually decreases as the supply flow rate of the grinding fluid increases, the flow rate exceeds a certain value (about 80 l / min).
It turned out that the thickness of the work-affected layer did not change much at the time. Also, with the right-angled nozzle 20 alone, no significant change was observed in the affected layer even if the flow rate was increased.

Further, in both the straight nozzle 10 and the right-angled nozzle 20, the thickness of the affected layer cannot be suppressed to 150 μm or less even if the flow rate is increased. The graph shown in FIG. 3 shows the thickness of the affected layer when the flow rate is changed while keeping the opening area of the right-angled nozzle 20 constant, that is, the thickness of the affected layer corresponding to the change in the flow velocity. ing. Note that the experimental values are obtained by performing the first conventional grinding method, that is, grinding the pin portion P at the center of the work spindle using an eccentric chuck, and performing the grinding at a normal grinding wheel peripheral speed.

From this graph, it can be seen that in the right-angled nozzle 20, as the flow velocity increases, the thickness of the affected layer decreases. This is considered to require a flow velocity of about 5.0 m / s or more in order to break through the air flow entrained by the rotation of the grinding wheel G and supply the grinding fluid to the surface of the grinding wheel G. However, when the flow velocity was about 5.0 m / s or more, no change was observed in the thickness of the affected layer. That is, even in the first conventional method which can sufficiently supply the grinding fluid to the grinding location, it is possible to sufficiently supply the grinding fluid to the grinding location if the flow rate of the right-angle nozzle alone is not more than 5.0 m / s. It can be seen that it is not possible to increase the flow velocity to 5.0 m / s or more, and that it does not affect the affected layer at all.

Therefore, in the second conventional grinding method, in which it is more difficult to supply the grinding fluid to the grinding point than in the first conventional technology, the grinding fluid supplied from the right-angled nozzle 20 has a flow rate of at least 5. It turned out that 0 m / s or more is necessary. From the above experimental results, it can be seen that in the straight nozzle 10, the thickness of the affected layer is changed in accordance with the flow rate, and in the right angle nozzle 20, the thickness of the affected layer is changed in accordance with the change in the flow velocity. I understood.

In addition, in both the straight nozzle 10 and the right-angled nozzle 20, even if the grinding fluid having an excessive flow rate and flow rate is supplied, only the capacity, cost, installation space, etc. of the pump and the tank are increased unnecessarily, and the effect is not so large. I understood that I could not get it. FIG. 5 is a graph showing a change in the flow rate and the thickness of the affected layer in the embodiment of the present invention in which the straight nozzle 10 and the right-angle nozzle 20 are installed.

Note that this experimental value indicates that the grinding efficiency Z ′ is 13
mm ³ / mm · s, whetstone peripheral speed 80 m / s, right angle nozzle 20
When the flow rate from the straight nozzle 10 and the right-angled nozzle 20 is changed by performing rough grinding with the flow rate from the straight nozzle 10 as a constant value of 7.7 m / s and the flow rate from the straight nozzle 10 as a fixed value of 6.0 m / s. It represents the displacement of the thickness of the altered layer. The reason why the flow velocity was set at around 7.7 m / s is that if the flow velocity exceeds 7.7 m / s, the pump capacity must be increased.
This is because the cost, the installation space, and the like increase.

As can be seen from this graph, by providing the straight nozzle 10 and the right-angled nozzle 20, the thickness of the affected layer was suppressed to 150 μm or less. Also, from the results of this experiment, if the flow velocity of the right-angled nozzle 20 is 5.0 m / s or more (7.7 m / s in this experiment), the thickness of the affected layer can be reduced even if the flow rate is slightly changed. It turned out to have little effect.

In addition, when the flow rate from the straight nozzle 10 was less than 25 L / min, the flow rate of the grinding fluid was too small, and the thickness of the affected layer rapidly increased. Therefore, at least the flow rate from the straight nozzle 10 is 25
It turns out that more than liter / min is necessary. FIG. 4 shows the thickness of the affected layer when the grinding efficiency Z ′ is changed.

It can be seen that as the grinding efficiency Z 'increases, the thickness of the affected layer increases. This is because the cutting speed and the cutting amount of the grinding wheel G increase,
This is because the grinding heat increases and the load on the workpiece increases. Even when the grinding efficiency Z 'changed, when the flow rate from the straight nozzle 10 became 50 liters / min or more, there was little change in the affected layer. Therefore,
In the configuration of the present invention, if the flow rate from the right angle nozzle 20 is 5.0 m / s or more and the flow rate from the straight nozzle 10 is in the range of 25 liters / min to 50 liters / min, Can be made sufficiently small, and the supply flow rate of the grinding fluid can be kept as low as possible. Preferably, the straight nozzle 10
And the total flow rate of the grinding fluid from the right angle nozzle 20 is 60 liter / m
By setting in or less, the tank capacity can be reduced, and the installation space and cost can be reduced.

The remaining affected layer is removed by fine grinding and fine grinding. Since the remaining affected layer can be made smaller (150 μm or less) than before, the working cycle can be further shortened. In the present embodiment, the grinding of the pin portion of the crankshaft is illustrated. However, the present invention is applicable to other workpieces, that is, grinding and cutting machines for processing a workpiece having a processing portion at a position eccentric from the center of rotation. It is also possible to apply. Further, for example, the present invention may be applied to a grinding machine for a cam portion of a cam shaft.

[0029]

According to the grinding machine of the present invention, the thickness of the damaged layer can be reduced by supplying the grinding fluid from the two nozzles, the straight nozzle and the right-angle nozzle. Further, by setting the flow rate from the straight nozzle in the range of 25 to 50 liters / min and the flow rate from the right-angle nozzle to 5.0 m / s or more, the thickness of the affected layer can be reduced even with a small amount of grinding fluid. Can be reduced more efficiently.

According to the method of supplying a grinding fluid in the grinding machine of the present invention, the grinding fluid is supplied from the straight nozzle to the grinding wheel at a flow rate of 25 to 50 liter / min toward the grinding point, and the grinding wheel is supplied with a flow rate of 5 to 5 l / min from the right angle nozzle. By supplying a grinding fluid of 0.0 m / s, cooling can be performed efficiently with a small amount of grinding fluid.
In addition, it is possible to reduce the size of the affected layer.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a grinding machine according to an embodiment of the present invention.

FIG. 2 is a graph showing experimental results in a conventional technique.

FIG. 3 is a graph showing experimental results in a conventional technique.

FIG. 4 is a graph showing experimental results in the embodiment of the present invention.

FIG. 5 is a graph showing experimental results in the embodiment of the present invention.

FIG. 6 is an explanatory view of a grinding machine according to a conventional technique.

[Explanation of symbols]

 5 Wheel head 10 Straight nozzle 20 Right angle nozzle

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroshi Morita 1-1-1 Asahi-cho, Kariya-shi, Aichi Prefecture Toyota Machine Works Co., Ltd. F-term (reference) 3C043 AC21 CC03 DD06 3C047 GG01 GG19

Claims (3)

[Claims] A workpiece that is driven to rotate by a work spindle; a grindstone table that moves forward and backward in a direction perpendicular to a rotation axis of the work spindle according to a rotation angle phase of the workpiece; A grinding machine provided with a grinding wheel that supports the grinding wheel and performs the grinding of the workpiece with the reciprocating movement of the grinding wheel stand.A grinding wheel is provided near an upstream side of a grinding point at which the grinding wheel and the workpiece come into contact with each other. A right-angled nozzle for supplying a grinding fluid from a direction orthogonal to a machining surface of a car and a straight nozzle for supplying a grinding fluid toward the grinding point are provided so as to move forward and backward integrally with the wheel head. A grinding machine characterized by the following: 2. The flow rate of the grinding fluid supplied from the right-angle nozzle is 5.0 m / s or more, and the flow rate of the grinding fluid supplied from the straight nozzle is in the range of 25 liter / min to 50 liter / min. The grinding machine according to claim 1, wherein: 3. The eccentric motion by rotating a crankshaft around a journal by a work spindle and moving a grinding wheel forward and backward in a direction perpendicular to the work spindle in accordance with a rotation angle phase of the crankshaft. In a grinding fluid supply method for a grinding machine that performs grinding of a pin portion of a crankshaft, the grinding fluid is provided in a direction orthogonal to a processing surface of a grinding wheel near an upstream side of a grinding point where the grinding wheel and a workpiece come into contact. The grinding fluid is supplied from the right-angled nozzle at a flow rate of 5.0 m / s or more, and is provided toward the grinding point when the center axis of the pin portion is located on the same horizontal line as the rotation axis of the grinding wheel. 25 liter / min or more and 50 liter / m from straight nozzle
A method of supplying a grinding fluid in a grinding machine, wherein the grinding fluid is supplied at a flow rate of in or less.