JP2003334745A - Grinding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinding method causing little slip of an abrasive grain by paying attention to the face that the slip of the abrasive grain is easily caused by up-cut grinding. <P>SOLUTION: The grinding is performed by rotating a workpiece W so as to send the workpiece W in the same direction B as the rotational direction A of a grinding wheel T in a contact part S of the grinding wheel T and the workpiece W to the rotating grinding wheel T. A water insoluble cutting oil agent may be used as a grinding oil agent, and the workpiece W having surface hardness higher than that of soft iron may be ground, and the peripheral surface of the workpiece W having a total length not shorter than a width may be ground. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a grinding method,
Specifically, the present invention relates to a grinding method in which a workpiece is rotated with respect to a rotating grindstone to perform grinding.

[0002]

2. Description of the Related Art In a grinder such as a cylindrical grinder or an inner surface grinder, a workpiece is rotated and brought into contact with a rotating grindstone, thereby grinding a peripheral surface or an end surface of the workpiece. Here, in the conventional grinding method, for example, as shown in FIG. 4, at the contact portion S between the grindstone T and the workpiece W, the grindstone T
The so-called "up-cut" is performed by rotating the workpiece so that the workpiece is fed in the opposite direction (arrow B) of the rotation direction (arrow A).
Was being ground. FIG. 4 shows a state in which the outer peripheral surface of the workpiece is ground by the cylindrical grinder, and the workpiece is rotated in the same direction as the rotation direction of the grindstone, but When grinding the peripheral surface, the workpiece is rotated in a direction opposite to the direction of rotation of the grindstone.

[0003]

In the up-cut grinding, as shown in FIG. 5, the workpiece W is fed in the direction (arrow B) opposite to the rotating direction (arrow A) of the grindstone T,
Although the surface of the workpiece W is scraped off by the abrasive grains R of the grindstone T (hatched portion in the drawing), since the abrasive grains R bite into the workpiece W from the portion where the grinding is completed, the biting start portion S
In No. 1, the biting angle of the abrasive grains R is small, and the abrasive grains R easily slip. In particular, when a water-insoluble cutting oil that can be regenerated and used is used as the grinding oil, the abrasive grains tend to slip. Also, when grinding a workpiece having a high surface hardness, the abrasive grains are likely to slip. Further, in the case of grinding the peripheral surface of a work piece formed in a long shape, when a grindstone is brought into contact with the work piece, the work piece bends in the opposite direction to the grindstone and escapes, so that slippage of abrasive grains is likely to occur.

When the abrasive grains slip in this way, the surface of the abrasive grains is flattened due to abrasion, and slippage is more likely to occur. Then, if the abrasive grains slip significantly, the amount of heat generated by the abrasive grain slip increases, which causes grinding burn.
In the conventional grinding method in which the workpiece is rotated to perform grinding, it is natural that grinding is performed by up-cutting, and no problems caused by up-cutting grinding have been considered.

The present invention has been made with a new focus on the above-mentioned problems caused by upcut grinding, and an object of the present invention is to provide a grinding method in which abrasive grains are unlikely to slip.

[0006]

According to a first aspect of the present invention, there is provided a grinding method in which a workpiece is fed to a rotating grindstone at a contact portion between the grindstone and the workpiece in the same direction as the rotating direction of the grindstone. It is characterized in that the workpiece is rotated to perform grinding.

In the present invention, so-called "downcut" grinding is performed in order to rotate the workpiece so that the workpiece is fed in the direction opposite to the rotating direction of the stone at the contact portion between the stone and the workpiece. And in grinding by down-cut,
Since the abrasive grains of the grindstone bite into the workpiece from the unground portion on the surface of the workpiece, the abrasive grain biting angle is large at the bite starting portion, and the abrasive grains are less likely to slip.

Further, in the upcut grinding, the amount of abrasive grains biting is small at the biting start portion, and the impact applied to the abrasive grains is small, whereas in the downcut grinding, the abrasive grain biting amount is small. Many, the impact applied to the abrasive grains becomes large. For this reason, the abrasive grains with reduced sharpness may not dig into the work piece satisfactorily and may be partially broken due to impact. In this case, a new cutting edge is reproduced at the tip of the abrasive grain, and good sharpness is secured. Therefore, for this reason also, the abrasive grains are less likely to slip.

As the grindstone used in the grinding method of the present invention, those in which abrasive grains are formed from various hard materials such as silicon nitride, silicon carbide, alumina, iron oxide and chromium oxide can be used. In down-grinding, the impact applied to the abrasive grains is large. Therefore, it is preferable to use a grindstone having abrasive grains formed of diamond or cubic boron nitride (CBN).

According to a second aspect of the present invention, there is provided a grinding method according to the first aspect, wherein a water-insoluble cutting fluid is used as a grinding fluid.

Here, the water-insoluble cutting oil is based on "mineral oil and animal and vegetable oils" or "mineral oil and ester oils",
An extreme pressure additive and an antioxidant are appropriately added to this base oil.

Grinding with a water-insoluble cutting oil tends to cause slippage of abrasive grains, as compared with the case of using a water-soluble cutting oil containing mineral oil and a surfactant as main components. By performing the down-cut grinding, it becomes possible to make the abrasive grains less likely to slip.

A grinding method according to a third aspect is the grinding method according to the second aspect, characterized in that a workpiece having a surface hardness higher than that of soft iron is ground.

When a workpiece having a high surface hardness is ground, it is difficult for the abrasive grains to bite into the workpiece, so that slippage of the abrasive grains is likely to occur. It is possible to prevent slippage.

Soft iron has a carbon (C) content of 0.0
Workpieces having a surface hardness of 3% or less, which is close to that of pure iron and have a surface hardness higher than that of soft iron, include "things made of a material harder than soft iron" and "a surface hardening treatment that hardens the surface. One thing can be mentioned.

Here, as a material harder than soft iron,
"Low carbon steel having a carbon content of 0.12 to 0.2%, medium carbon steel having a carbon content of 0.2 to 0.45%, and high carbon steel having a carbon content of 0.5% or more. Containing 0.
"035-1.7% carbon steel", "carbon content is 1.7-
6.88% cast iron "," nickel (Ni), manganese (Mn), tungsten (W), chromium (Cr), molybdenum (Mo), cobalt (Co), vanadium (V), aluminum (Al), etc. Alloy steel added to carbon steel "," nickel (Ni), manganese (Mn), tungsten (W), chromium (Cr), molybdenum (M
o), cobalt (Co), vanadium (V), aluminum (Al) and other metal powders sintered ".

As the surface hardening treatment, "hardening treatment such as flame hardening, induction hardening, laser hardening, etc."
Examples of the treatment include a “shot peening treatment” and a “curing treatment such as carburizing, nitriding, carbonitriding, and sulfurizing” for forming a hard coating layer on the surface of the workpiece.

According to a fourth aspect of the present invention, in the grinding method according to any one of the first to third aspects, a peripheral surface of a work piece having a total length equal to or larger than a width is ground. It is characterized by.

Here, the width dimension of the workpiece is, for example, a diameter dimension when the workpiece has a substantially cylindrical shape,
In the case of a shape in which the small diameter portion is partially provided, it is the dimension of the diameter of the small diameter portion which is the minimum width dimension. Further, the work piece is not limited to a cylindrical shape, and may have a non-circular cross section such as an elliptical shape or an appropriate cam shape. In this case, the width dimension is on a plane orthogonal to the rotation axis of the work piece. It is the size of the smallest part in.

A work piece whose overall length is equal to or larger than the width has low rigidity against stress in the width direction and is apt to bend in the width direction. Therefore, when grinding the outer peripheral surface and the inner peripheral surface of such a workpiece, escape due to the bending of the workpiece itself occurs, and slippage of the abrasive grains easily occurs. On the other hand, in the present invention,
By performing grinding by down-cutting, it becomes possible to make slippage of abrasive grains less likely to occur. In particular, the total length dimension is twice or more the width dimension, preferably 5 times or more, more preferably 1.
The present invention can be favorably applied when grinding the peripheral surface of a long work piece having a size of 0 times or more.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. First, a cylindrical grinder as a grinder used in the grinding method according to the present invention will be described. The grinding method according to the present invention is not limited to a cylindrical grinder, and can be carried out using various grinders such as an inner surface grinder that supports and rotates a work piece.

As shown in FIG. 1, the grinding machine 10 of this example is
A bed 20 that constitutes a base portion, a grindstone base 30 and a table 40 that are respectively placed on the bed 20 are provided. Here, the grindstone base 30 is for rotatively driving the disk-shaped grindstone T, and is provided with a drive device 32 such as a motor for rotatively driving the grindstone shaft 31 on which the grindstone T is mounted. Then, this grindstone base 30 is provided on the upper surface of the bed 20 with the workpiece W.
Is mounted slidably in the X-axis direction (arrow X), which is the radial direction of, and a drive transmission mechanism such as a feed screw mechanism is driven by a drive device 33 such as a servo motor capable of accurately determining the rotation angle. It is driven to move in the X-axis direction via. The grindstone T mounted on the grindstone base 30 is substantially entirely covered with a cover (not shown).

On the other hand, the table 40 has a headstock 4 on one end side.
1 and a tailstock 42 on the other end side, and the work W is rotatably supported between the center 46 of the headstock 41 and the center 46 of the tailstock 42. The table 40 is mounted on the upper surface of the bed 20 so as to be slidable in the Z-axis direction (arrow Z), which is the axial direction of the workpiece W, and can accurately determine the rotation angle. Are driven and moved in the Z-axis direction via a drive transmission mechanism such as a feed screw mechanism.

The headstock 41 is provided with a main spindle 43 which is rotationally driven by a drive device 44 such as a servomotor capable of accurately determining the rotation angle. And the headstock 4
The workpiece W supported between the center 46 of the No. 1 and the center 46 of the tailstock 42 is subjected to grinding by a well-known turning tool (not shown) attached to the workpiece W and the like.
It is rotationally driven around the C axis (arrow C) with the rotation axis of 3 as the central axis.

In the grinding machine 10 of this embodiment, a revolving table (not shown) is rotatably supported on the upper surface of the table 40 so that the workpiece W can be supported on the revolving table. The grindstone base 30 may be rotatably supported on the bed 20 on a horizontal plane. The axis of the grindstone T and the axis of the workpiece W in the parallel state can be tilted relative to each other by adopting the turning table as described above or by turning the grindstone base 30. The end surface of the desired portion of the work W can be suitably ground.

By the way, in this example, as the workpiece W, various alloys such as nickel chrome steel steel (SNC), nickel chrome molybdenum steel steel (SNCM), chrome steel steel (SCr) and chrome molybdenum steel steel (SCM) are used. It uses a camshaft made of steel. Generally, when a raw material of iron-based material such as steel is ground, a relatively long chip is generated, which easily causes clogging of the grindstone and falling of the abrasive grains. Therefore, it is adopted as the workpiece W of this example. The surface of the alloy steel to be formed (at least the cam surface of the cam shaft) is subjected to surface hardening treatment such as induction hardening. Here, when grinding the cam surface, the grindstone T and the cam shaft (workpiece W)
The water-insoluble cutting fluid ejected from the coolant nozzle (not shown) is applied to the grinding action portion which is in contact with. Further, the camshaft (workpiece W) is formed by integrally forming a plurality of cam portions W2 on a shaft portion W1 having a small diameter, and has a long length whose length dimension is larger than the diameter dimension of the shaft portion W1. It was formed. Such a work W
Has a surface hardness of the surface to be ground (cam surface) higher than that of soft iron, and has a relatively low rigidity that is easily bent in the radial direction during grinding.

When the above-mentioned workpiece W is ground by up-cutting, the abrasive grains are likely to slip and grinding burn is likely to occur. Therefore, in the grinding method of this example, as shown in FIG. 2, a direction (arrow B) opposite to the rotating direction of the grindstone T (arrow A).
The work W is rotated in such a manner that the work W is fed in the same direction (arrow B) as the rotation direction (arrow A) of the grindstone T at the contact portion S between the grindstone T and the work W. Grind. In such down-cut grinding, as shown in FIG. 3, the workpiece W is sent in the same direction (arrow A) as the rotation direction (arrow A) of the grindstone T, and the abrasive grains R of the grindstone T start to bite. In the portion S1, the abrasive grains R bite into the workpiece W at a large angle from the unground portion of the workpiece W, and the surface of the workpiece W is scraped off by the movement of the abrasive grains R (hatched portion in the figure). Therefore, the abrasive grains R are unlikely to slip.

In the grinding method of this example, the grindstone T is formed of superabrasive grains made of diamond or cubic boron nitride (CBN) so that it can withstand the impact of the abrasive grains R at the beginning of biting. Things have been adopted. Further, as the grinding condition, the rotation speed of the grindstone T is set to be higher than that in the case where grinding is performed by upcut, or the workpiece W is
The rotation speed of is set slow. As a result, when the abrasive grains R start to bite, the bite amount K is small and the impact applied to the abrasive grains R is small.

Although an example of the grinding method according to the present invention has been described above, the grinding method according to the present invention is not limited to this. For example, when the inner peripheral surface of the workpiece is ground by the inner surface grinding machine, down-cut grinding may be performed.

[0030]

According to the grinding method of the present invention described above, the following effects can be obtained.

According to the first aspect of the present invention, the downcut can cause the abrasive grains to bite into the workpiece at a large angle, so that the slippage of the abrasive grains can be suppressed. Further, due to the impact of the abrasive grains starting to bite, a new cutting edge is easily regenerated at the tip of the abrasive grain, and it is easy to secure good sharpness of the abrasive grain, and for this reason also, slippage of the abrasive grain is less likely to occur. be able to.

According to the second aspect of the present invention, even if the water-insoluble cutting oil is used, it is possible to make the abrasive grains less likely to slip.

According to the third aspect of the invention, it is possible to prevent the abrasive grains from slipping even when grinding a workpiece having a high surface hardness.

According to the invention as set forth in claim 4, even when grinding a work piece having an overall length equal to or larger than the width, it is possible to prevent the abrasive grains from slipping.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a grinder used in a grinding method according to the present invention.

FIG. 2 is a side view showing rotation directions of a grindstone and a workpiece in a grinding method according to the present invention.

FIG. 3 is an explanatory view schematically showing a downcut grinding state.

FIG. 4 is a side view showing rotation directions of a grindstone and a workpiece in a conventional grinding method.

FIG. 5 is an explanatory view schematically showing an upcut grinding state.

[Explanation of symbols]

T whetstone W work 10 grinder 20 beds 30 whetstone stand 40 tables 41 Headstock 42 tailstock 43 spindle

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshinobu Yotsui             1-1 Asahi-cho, Kariya city, Aichi             Machine Co., Ltd. F-term (reference) 3C043 AA01 CC03

Claims (4)

[Claims] 1. A rotating grindstone is ground by rotating the workpiece so that the workpiece is fed in the same direction as the rotating direction of the grindstone at the contact portion between the grindstone and the workpiece. Grinding method. 2. The grinding method according to claim 1, wherein a water-insoluble cutting oil is used as the grinding oil. 3. The grinding method according to claim 1, wherein a workpiece having a surface hardness higher than that of soft iron is ground. 4. The grinding method according to any one of claims 1 to 3, characterized in that a peripheral surface of a work piece having a total length equal to or larger than a width is ground.