KR20150067532A - Machine tool - Google Patents

Abstract

The present invention relates to a machine tool. According to an embodiment of the present invention, the machine tool comprises: a bed; a slider installed to linearly reciprocate on the bed; and a sliding bearing installed on one surface of the slider facing the bed. The sliding bearing comprises: a bearing plate; a division groove dividing the bearing plate into a plurality of areas; and an oil groove formed on each divided area of the bearing plate and supplying lubricant.

Description

Machine tool {MACHINE TOOL}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a machine tool, and more particularly, to a machine tool including a slider that linearly reciprocates on a bed.

Machine tools are machines that are used for machining metal or non-metal workpieces to various shapes and sizes using various cutting or non-cutting methods.

Machine tools are largely classified as turning centers and machining centers. And machine tools often include sliders that perform a linear reciprocating motion on the bed, which requires precise movement. In particular, a machine tool using a numerical control (NC) requires a precise movement of the slider because the precise movement of the workpiece or tool greatly affects the machining accuracy of the workpiece.

In a machine tool, a chuck supporting a workpiece or a spindle on which a tool is mounted is mounted on a slider. The slider can then be moved on the bed via a rail system, a ballscrew system, or a linear guide system. In this case, the linear guide type slider can have high accuracy.

The slider of the linear guide type is slidably movable through a sliding bearing provided on a side opposite to the bed. The contact surface between the sliding bearing and the bed is coated with a lubricant to reduce friction.

However, when the slider moves on the bed and stops after a certain period of time for processing, the lubricant on the contact surface between the slider and the bed is not formed with the oil film and friction is generated. If such an operation is repeated for a long time, the clearance between the bed and the sliding bearing increases due to wear, which may affect the machining accuracy of the machine tool, and the noise and vibration are also seriously increased.

Embodiments of the present invention provide a machine tool in which the friction of a slider that reciprocates linearly on a bed is effectively minimized.

According to an embodiment of the present invention, a machine tool includes a bed, a slider installed to be linearly reciprocable on the bed, and a sliding bearing installed on one surface of the slider facing the bed. The sliding bearing includes a bearing plate, a divided groove dividing the bearing plate into a plurality of regions, and an oil groove formed in each of the divided regions of the bearing plate to supply lubricating oil.

The divided grooves may be elongated in a direction crossing the moving direction of the slider so that the divided areas of the bearing plate are arranged along the moving direction of the slider.

The split groove and the oil groove may be formed parallel to each other.

In the above-described machine tool, the interior of the split groove may be at atmospheric pressure.

One or two split grooves may be formed to divide the bearing plate into two or three.

The split grooves may have a depth in the range of greater than 1.5 mm but less than 4.5 mm.

The split grooves may have a width in the range of greater than 7 mm but less than 11 mm.

According to the embodiment of the present invention, the machine tool can effectively minimize the friction of the slider reciprocating linearly on the bed.

FIG. 1 is a perspective view showing a main part of a machine tool according to an embodiment of the present invention.
2 is a rear view of the slider supporting the table of Fig.
3 is a perspective view showing the sliding bearing of FIG.
4 is a perspective view showing a sliding bearing according to a comparative example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

The drawings are schematic and illustrate that they are not drawn to scale. The relative dimensions and ratios of the parts in the figures are shown exaggerated or reduced in size for clarity and convenience in the figures, and any dimensions are merely illustrative and not restrictive. And to the same structure, element or component appearing in more than one drawing, the same reference numerals are used to denote similar features.

The embodiments of the present invention specifically illustrate ideal embodiments of the present invention. As a result, various variations of the illustration are expected. Thus, the embodiment is not limited to any particular form of the depicted area, but includes modifications of the form, for example, by manufacture.

Hereinafter, a machine tool 101 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG.

1, a machine tool 101 according to an embodiment of the present invention includes a bed 600, a slider 400, and a sliding bearing 500 (shown in FIG. 2) .

The machine tool 101 according to an embodiment of the present invention may further include a table 200 and a spindle 300 for holding a workpiece or a tool, respectively. Here, the table 200 and the spindle 300 may be installed on the slider 400, respectively. 1, the slider 400 supports the table 200 and the slider 400 supports the spindle 300. Hereinafter, the slider 400 includes a slider 400 supporting the table 200, . The slider 400 supporting the spindle 300 has the same technical idea as the slider 400 supporting the table 200

The bed 600 is disposed on the floor or the bottom surface of the building structure to support various parts of the machine tool 101.

In an embodiment of the present invention, the bed 600 may include a linear motion (LM) guide portion 650 that guides the slider 400 to reciprocate linearly.

The slider 400 is installed on the bed 600 so as to reciprocate linearly. Specifically, the slider 400 is slidably engaged with the linear motion guide portion 650 of the bed 600.

2, the sliding bearing 500 is installed on one side of the slider 400 facing the bed 600 to facilitate the linear reciprocating motion of the slider 400. As shown in FIG.

Specifically, the sliding bearing 500 is installed on one surface of the slider 400 and is in surface contact with the linear motion guide portion 650 of the bed 600.

The sliding bearing 500 can support a relatively high load as compared to other sliding members such as ball bearings or roller bearings.

Since the sliding bearing 500 moves in a state of being in contact with the linear motion guide portion 650 of the bed 600, the sliding bearing 500 is generated on the contact surface between the sliding bearing 500 and the bed 600 due to wear, The gap is relatively small. Therefore, when the sliding bearing 500 is used, the noise and vibration generated in the machine tool 101 can be effectively suppressed.

The machine tool 101 according to an embodiment of the present invention further includes lubricant applied to a contact surface between the sliding bearing 500 and the linear motion guide portion 650 of the bed 600. [

In one embodiment of the present invention, the sliding bearing 500 includes a bearing plate 510, a split groove 550, and an oil groove 580, as shown in FIG.

The bearing plate 510 is in direct contact with the linear motion guide portion 650 of the bed 600.

The split groove 550 divides the bearing plate 510 into a plurality of regions. That is, the bearing plate 510 is divided into a plurality of independent regions by the division grooves 550.

The divided areas of the bearing plate 510 are arranged along the sliding movement direction of the slider 400 by the split grooves 550. [ That is, the split grooves 550 are elongated in the direction crossing the moving direction of the slider.

Also, in one embodiment of the present invention, the interior of the split groove 550 is at atmospheric pressure. Therefore, the divided areas of the bearing plate 510 are formed by the divided grooves 550, independent of each other, and the oil film and the pressure are formed.

Further, in one embodiment of the present invention, one or two division grooves 550 may be formed. That is, the bearing plate 510 can be divided into two or three by the split groove 550. On the other hand, if the number of the divided grooves 550 is three or more, the contact surface of the bearing plate 510 on which the oil film is to be formed may be relatively small, and the friction may be rather increased.

Also, in one embodiment of the present invention, the split groove 550 has a depth in the range of greater than 1.5 mm but less than 4.5 mm. And the split groove 550 has a width in the range of greater than 7 mm but less than 11 mm.

Atmospheric pressure is not formed inside the divided groove 550 and the divided groove 550 is formed independently in the region divided by the divided groove 550 when the depth of the divided groove 550 is 1.5 mm or less or the width of the divided groove 550 is 7 mm or less, Can not be formed. If the depth of the split groove 550 is equal to or greater than 4.5 mm or the width of the split groove 550 is equal to or greater than 11 mm, the contact surface of the bearing plate 510 on which the oil film is to be formed may be relatively small and friction may be increased.

An oil groove 580 is formed in each of the divided regions of the bearing plate 510 by the split grooves 550 to supply lubricating oil. And the oil groove 580 may be formed parallel to the split groove 550. [

Further, an oil supply hole 581 may be formed in one region of the oil groove 580. The oil supply hole 581 can supply lubricating oil to be accommodated in the oil groove 580.

An oil film is formed between the bearing plate 510 and the bed 600 by the lubricating oil supplied through the oil supply hole 581 of the oil groove 580 and a constant pressure is applied to the oil film. At this time, the oil film pressure is increased by the oil groove 585, and the supply of lubricating oil is smooth. Specifically, when the sliding groove 500 is formed with the oil groove 580, when the slider 400 slides along the linear motion guide portion 650 of the bed 600, the direction in which the oil film thickness of the lubricating oil slides The pressure of the oil film can be increased. When the pressure of the oil film is increased as described above, the friction between the sliding bearing 500 and the linear motion guide unit 650 can be reduced by supporting the pressure applied between the slider 400 and the bed 600.

The slider 400 performs a linear reciprocating motion. In the linear reciprocating motion, the moving speed is zero at a point where the moving direction is changed due to the physical motion characteristic thereof. The number of times that the moving speed per one linear reciprocating motion becomes zero is two do. In the fluid lubrication theory, formation of the oil film is difficult when the kinetic velocity is zero.

However, according to the embodiment of the present invention, since the lubricant is received in the oil groove 580, when the slider 400 is moved again after stopping for machining, the lubricating oil accommodated in the oil groove 580 is supplied to the sliding bearing 500 The lubrication state between the linear motion guide portions 650 of the bed 600 can be efficiently improved and maintained.

In addition, in one embodiment of the present invention, the bearing plate 510 is divided into the plurality of areas by the divided grooves 550 and the divided grooves 550 are in the atmospheric pressure state, so that the oil film is independently formed in each divided area .

Accordingly, the oil film and pressure due to the lubricating oil supplied through the oil groove 580 can be more uniformly formed on the bearing plate 510 as a whole.

That is, by increasing the pressure of the oil film formed on the contact surface between the sliding bearing 500 and the bed 600, the slider 400 can support a relatively high load. Further, the oil groove 580 can smoothly supply the lubricating oil to reduce the occurrence of wear.

The oil groove 580 and the split groove 550 can capture and store foreign substances generated in the abrasion between the sliding bearing 500 and the linear motion guide portion 650 of the bed 600, respectively. Such foreign matter may increase the friction, shortening the life of the sliding bearing 450 or damaging the linear motion guide portion 540 of the bed 500.

The split grooves 550 and the oil grooves 580 may also be formed using a laser or by various methods known to those skilled in the art such as etching, focused ion beam, or ion etching. At this time, the split grooves 550 and the oil grooves 580 can be micromachined in micrometer units.

With such a structure, the machine tool 101 according to the embodiment of the present invention effectively supports the table 200 or the spindle 300 and effectively minimizes the friction of the slider 400 that reciprocates linearly on the bed 500 can do.

The split grooves 550 and the oil grooves 580 formed in the sliding bearing 500 can reduce the friction between the sliding bearing 500 and the linear motion guide portion 650 of the bed 600. [

Particularly, the lubricating oil accommodated in the oil groove 580 improves the lubrication condition, thereby reducing the wear occurring at the interface between the sliding bearing 500 and the linear motion guide portion 650 of the bed 600. [

According to an embodiment of the present invention, the distribution of the oil film formed on the contact surface between the sliding bearing 500 and the bed 600 is uniformized through the split groove 550 and the oil groove 580 and the pressure of the oil film is increased A relatively high load can be supported.

Further, the split grooves 550 and the oil grooves 580 can trap the abrasive particles to suppress the damage of the sliding bearing 500 and the bed 600. [

Hereinafter, the effects of the division of the divided grooves 550 for dividing the bearing plate 510 of the sliding bearing 400 will be described through various experiments.

Experiment 1 was conducted in such a manner that the coefficient of friction was measured while varying the number, depth, and width of the divided grooves 550.

size Average coefficient of friction Number () Depth (mm) Width (mm) One 2 8 0.0166 One 2 10 0.0162 One 2 12 0.0180 One 4 8 0.0185 One 4 10 0.0183 One 4 12 0.0190 One 6 8 0.0235 One 6 10 0.0211 One 6 12 0.0260 2 2 8 0.0158 2 2 10 0.0156 2 2 12 0.0172 2 4 8 0.0184 2 4 10 0.0182 2 4 12 0.0189 2 6 8 0.0215 2 6 10 0.0211 2 6 12 0.0218 3 2 8 0.0251 3 2 10 0.0241 3 2 12 0.0272 3 4 8 0.0261 3 4 10 0.0244 3 4 12 0.0287 3 6 8 0.0288 3 6 10 0.0272 3 6 12 0.0291

Table 1 shows the results of Experiment 1. Table 1 shows the average values of friction coefficients measured by different numbers of depths, widths, and widths of the split grooves 550 under different conditions.

In Table 1, it can be seen that the coefficient of friction is relatively reduced when the number of the divided grooves 550 is one or two. Further, it can be confirmed that the friction coefficient is relatively reduced when the depth of the split groove 550 is 2 mm to 4 mm and the width of the split loop 550 is 8 mm to 10 mm.

Particularly, it can be confirmed that when the number of the divided grooves 550 is 2, the depth 550 of the divided grooves is 2 mm, and the width of the divided grooves 550 is 10 mm, the friction coefficient is remarkably lowered.

In Experiment 2, as shown in Fig. 4, a sliding bearing 50 having an oil groove 58 of a zigzag pattern bent at right angles without forming the dividing groove 550 of Fig. 3 is formed on the bearing plate 51 In the comparative example and the sliding bearing 500 in which two split grooves 550 are formed according to an embodiment of the present invention, the depth of the split groove 550 is 2 mm and the width of the split groove 550 is 10 mm. And the friction coefficient was measured in comparison with the above.

Oil groove shape Split groove dimensions Average coefficient of friction Number () Length (mm) Width (mm) Experimental Example Straight 2 2 10 0.0156 Comparative Example  shape No split groove 0.0336

Table 2 shows the results of Experiment 2. The experimental example and the comparative example differ in the presence or absence of the split grooves 550. In the experimental examples and the comparative examples, the oil grooves 580 and 58 are different in shape only, and the overall dimensions such as the width and the depth are very small.

As shown in Table 2, it can be confirmed that the friction coefficient of the experimental example is remarkably lower than twice that of the comparative example.

As described above, it was confirmed that the sliding bearings 500 of the machine tool 101 according to the embodiment of the present invention can effectively reduce the friction with the bed 600 through the experiments 1 and 2. [

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. will be.

It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, It is intended that all changes and modifications derived from the equivalent concept be included within the scope of the present invention.

101: Machine tool 200: Table
300: spindle 400: slider
500: Sliding bearing 510: Bearing plate
550: split groove 580: oil groove
600: Bed 650: Linear guide motion

Claims (7)

Bed;
A slider provided on the bed so as to be linearly reciprocable; And
A sliding bearing provided on one surface of the slider facing the bed,
/ RTI >
The sliding bearing includes:
A bearing plate;
A split groove dividing the bearing plate into a plurality of regions; And
An oil groove formed in each of the divided regions of the bearing plate to supply lubricating oil,
. The method of claim 1,
Wherein the divided grooves are elongated in a direction crossing the moving direction of the slider so that the divided areas of the bearing plate are arranged along the moving direction of the slider. 3. The method of claim 2,
Wherein the split groove and the oil groove are formed parallel to each other. 4. The method according to any one of claims 1 to 3,
Wherein the inside of the split groove is at atmospheric pressure. 5. The method of claim 4,
Wherein one or two split grooves are formed to divide the bearing plate into two or three. The method of claim 5,
Wherein the split groove has a depth in the range of greater than 1.5 mm but less than 4.5 mm. 5. The method of claim 4,
Wherein the split groove has a width in the range of more than 7 mm but less than 11 mm.

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