KR102062406B1 - Machine tool - Google Patents

Abstract

The present invention relates to a machine tool, the machine tool according to an embodiment of the present invention is a machine tool is a sliding bearing installed on the bed, the slider installed on the bed to reciprocate linearly, and one surface of the slider facing the bed (sliding bearing). The sliding bearing includes a bearing plate, an oil groove formed on one surface of the bearing plate facing the bed to supply lubricating oil, and a plurality of scraping holes formed on one surface of the bearing plate. ).

Description

Machine tool {MACHINE TOOL}

Embodiments of the present invention relate to machine tools, and more particularly to machine tools including sliders that linearly reciprocate on a bed.

A machine tool refers to a machine that uses various cutting or non-cutting methods for the purpose of processing metal or nonmetal workpieces into desired shapes and dimensions using various tools.

Machine tools are largely divided into Turning Centers and Machining Centers. And most machine tools include sliders that linearly reciprocate on the bed, which requires precise movement. In particular, a machine tool using numerical control (NC) requires more precise movement of the slider since the precise movement of the workpiece or tool greatly affects the machining precision of the workpiece.

In a machine tool, a spindle on which a chuck or tool for supporting a workpiece is mounted is mounted to a slider. And the slider can be moved on the bed through a rail method, a ball screw method, or a linear guide method. Among these, the slider of the linear guide system can have high precision.

The linear guide slider is slidably movable through a sliding bearing installed on one surface facing the bed. A lubricant is applied to the sliding bearing and the contact surface of the bed to reduce friction.

However, when the slider moves on the bed, stops for a certain time for processing, and then moves again, the lubricant on the contact surface of the slider and the bed does not form an oil film, causing friction. If this operation is repeated for a long time, the gap between the bed and the sliding bearing is increased due to wear, which may affect the precision of the machine tool processing, there is a problem that noise and vibration is also increased to a serious level.

Embodiments of the present invention provide a machine tool that effectively minimizes wear of a slider that linearly reciprocates on a bed.

According to an embodiment of the present invention, a machine tool includes a bed, a slider linearly reciprocally mounted on the bed, and a sliding bearing installed on one surface of the slider facing the bed. The sliding bearing includes a bearing plate, an oil groove formed on one surface of the bearing plate facing the bed to supply lubricating oil, and a plurality of scraping holes formed on one surface of the bearing plate. ).

The average depth of the scraping holes may be in the range of 1 micrometer to 5 micrometers.

In addition, the ratio of the bearing area of the bearing plate and the bed to the total area of the bearing plate may be in the range of 50% to 60%.

Surfaces facing the bed of the bearing plate may have an inclination, and the entire thickness of the bearing plate may be uneven.

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

1 is a perspective view showing a main portion of a machine tool according to an embodiment of the present invention.
FIG. 2 is a rear view of the slider supporting the table of FIG. 1. FIG.
3 is a perspective view illustrating the sliding bearing of FIG. 2.
4 is an enlarged plan view of a portion of FIG. 2.
5 is a cross-sectional view taken along the line VV of FIG. 4.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

It is noted that the figures are schematic and not drawn to scale. The relative dimensions and ratios of the parts in the figures have been exaggerated or reduced in size for clarity and convenience in the figures and any dimensions are merely exemplary and not limiting. And the same reference numerals are used to refer to similar features in the same structure, element or part shown in more than one figure.

Embodiments of the invention specifically illustrate ideal embodiments of the invention. As a result, various modifications of the drawings are expected. Thus, the embodiment is not limited to the specific form of the illustrated region, but includes, for example, modification of the form 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.

As shown in FIG. 1, the 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). Include.

And the machine tool 101 according to an embodiment of the present invention may further include a table 200 and the spindle 300 for holding the workpiece or the tool, respectively. Here, the table 200 and the spindle 300 may be installed on the slider 400, respectively. In FIG. 1, both the slider 400 for supporting the table 200 and the slider 400 for supporting the spindle 300 are illustrated, but the slider 400 is a slider 400 for supporting the table 200. Explain the center. The slider 400 supporting the spindle 300 also has the same technical concept as the slider 400 supporting the table 200.

Bed 600 is placed on the ground or the bottom of the building structure to serve to support the various components of the machine tool (101).

In one embodiment of the present invention, the bed 600 may include a linear motion (LM) guide 650 for guiding the slider 400 to reciprocate linearly.

The slider 400 is installed on the bed 600 so as to be linearly reciprocated. In detail, the slider 400 is slidably coupled to the linear motion guide part 650 of the bed 600.

As illustrated in FIG. 2, the sliding bearing 500 is installed on one surface of the slider 400 facing the bed 600 to help linear reciprocation of the slider 400.

In detail, the sliding bearing 500 is installed on one surface of the slider 400 to make surface contact with the linear motion guide part 650 of the bed 600.

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

In addition, since the sliding bearing 500 moves in surface contact with the linear motion guide part 650 of the bed 600, the sliding bearing 500 may be generated on the contact surface between the sliding bearing 500 and the bed 600 due to abrasion even when used for a long time. The gap is relatively small. Therefore, when using the sliding bearing 500, it is possible to effectively suppress the noise and vibration generated in the machine tool 101.

In addition, the machine tool 101 according to an embodiment of the present invention further includes a lubricating oil applied to a contact surface between the sliding bearing 500 and the linear motion guide part 650 of the bed 600.

In one embodiment of the invention, the sliding bearing 500, as shown in Figure 3, the bearing plate 510, the oil groove 580, and a plurality of scraping holes (519) ( 4).

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

An oil groove 580 is formed on one surface of the bearing plate 510 facing the bed 600 to supply lubricating oil. In addition, an oil supply hole 589 may be formed in one region of the oil groove 580. The oil supply hole 589 may 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 lubricating oil supplied through the oil supply hole 589 of the oil groove 580, and a constant pressure is applied to the oil film 580.

The oil groove 580 may be formed using a laser, or may be formed using various methods known to those skilled in the art, such as etching, focused ion beam, or ion etching. In this case, the oil groove 580 may be finely processed in units of micrometers.

In addition, in FIG. 3, the oil groove 580 is formed in a “d” shape or an uneven pattern, but an embodiment of the present invention is not limited thereto. That is, the oil groove 580 may be formed in various patterns known to those skilled in the art.

The scraping hole 519 is formed on one surface of the bearing plate 510 facing the bed 600. That is, the scraping hole 519 and the oil groove 580 are formed on the same surface. In one embodiment of the present invention, the scraping holes 519 may have an average depth in the range of 1 micrometer to 5 micrometers, as shown in FIGS. 4 and 5. 4 is an enlarged plan view of region A of FIG. 3.

In addition, in one embodiment of the present invention, the scraping hole 519 so that the ratio of the contact area of the bearing plate 510 and the bed 600 to the total area of the bearing plate 510 is in the range of 50% to 60%. ) May be formed. In this case, an area in which the oil groove 580 and the scraping hole 519 are formed on one surface of the bearing plate 510 facing the bed 600 may be a non-contact area, and the remaining area may be a contact area.

Hereinafter, the ratio of the contact area between the bearing plate 510 and the bed 600 to the total area of the bearing plate 510 is referred to as a bearing ratio (bearing ratio).

In addition, the surface of the bearing plate 510 facing the bed 600 may have an inclination, and the entire thickness of the bearing plate 510 may be non-uniformly formed.

As such, the reason why the thickness of the bearing plate 510 is formed to be non-uniform is to correct an error caused by tolerance or deformation due to heat or load.

That is, by varying the thickness of the bearing plate 510 sliding in contact with the bed 600 in the sliding bearing 500, the operation precision of the table 200 or the spindle 300 supported on the slide 400 is adjusted. Can be improved.

The scraping holes 519 may be formed by various scraping methods known to those skilled in the art. In addition, the thickness variation of each region of the bearing plate 510 may be implemented through a scraping method. That is, the bearing plate 510 of the machine tool 101 according to an embodiment of the present invention may be scraped through various scraping methods to form the scraping hole 519 as well as the bearing plate ( The thickness of 510 may be formed to be uneven overall.

As such, in one embodiment of the present invention, since the oil groove 580 and the plurality of scraping holes 519 are formed on one surface of the bearing plate 510, the wear of the sliding bearing 500 may be reduced.

Specifically, an oil groove 580 and a plurality of scraping holes 519 are formed on one surface of the bearing plate 510 in contact with the bed 600 such that the bed 600 and the sliding bearing 500 face each other side by side. Even when the movement is generated, the wedge effect is generated to generate a fluid dynamic pressure effect between two surfaces of the bearing plate 510 and the bed 600 that face each other.

Therefore, the oil film pressure is increased between the sliding bearing 500 and the bed 600, and the supply of lubricating oil is smoothed. This is because the oil groove 580 and the scraping hole 519 slide along the direction in which the oil film thickness of the lubricant slides as the slider 400 slides along the linear motion guide portion 650 of the bed 600. This is because the wedge effect occurs.

As such, when the pressure of the oil film is increased, the pressure generated between the slider 400 and the bed 600 may be supported to reduce wear occurring between the sliding bearing 500 and the linear motion guide part 650.

Slider 400 is a linear reciprocating motion, the linear reciprocating motion is a movement speed of 0 at the point of the change in the direction of movement due to its physical movement characteristics, the number of times that the movement speed becomes zero per one cycle of linear reciprocation occurs twice do. In the fluid lubrication theory, when the speed of movement reaches zero, formation of the oil film is difficult.

However, according to one embodiment of the present invention, since the lubricant is accommodated in the oil groove 580 and the scraping hole 519, the slider 400 is accommodated in the oil groove 580 when the slider 400 moves again after stopping for processing. Lubricating oil can efficiently improve and maintain the lubrication state between the sliding bearing 500 and the linear motion guide portion 650 of the bed 600.

That is, the oil film and pressure by the lubricating oil supplied through the oil groove 580 may be more uniformly formed in the bearing plate 510 through the plurality of scraping holes 519.

As such, since the pressure of the oil film formed on the contact surface between the sliding bearing 500 and the bed 600 is increased, the slider 400 can support a relatively high load and reduce the occurrence of wear.

In addition, the oil groove 580 and the scraping hole 519 may capture and store foreign substances generated from wear between the sliding bearing 500 and the linear motion guide part 650 of the bed 600, respectively. Such foreign matters may increase friction to shorten the life of the sliding bearing 500 or damage the linear motion guide part 650 of the bed 600.

By such a configuration, the machine tool 101 according to the embodiment of the present invention supports the table 200 or the spindle 300 to effectively minimize the friction of the slider 400 linearly reciprocating on the bed 500. can do.

Specifically, the oil groove 580 and the plurality of scraping holes 519 formed in the bearing plate of the sliding bearing 500 may reduce wear occurring between the slider 400 and the bed 600.

In particular, the lubricating oil contained in the oil groove 580 and the plurality of scraping holes 519 improves the lubrication state so that wear occurs at the interface between the sliding bearing 500 and the linear motion guide 650 of the bed 600. Can be reduced.

In addition, according to an embodiment of the present invention, the oil groove 580 and the plurality of scraping holes 519 to uniform the distribution of the oil film formed on the contact surface of the sliding bearing 500 and the bed 600 and By increasing the pressure it is possible to support relatively high loads.

In addition, the oil groove 580 and the plurality of scraping holes 519 may trap the wear particles to suppress damage to the sliding bearing 500 and the bed 600.

Hereinafter, the effects of the specifications and the bearing ratio (bearing ratio, bearing capacity ratio) of the scraping hole 519 formed in the bearing plate 510 of the sliding bearing 400 will be described through various tests.

Experiment 1 proceeded by measuring the thickness and friction coefficient of the oil film while varying the average depth and bearing ratio of the scraping hole 519, respectively.

Specification Measures Average Depth (μm) Bearing ratio (%) Oil film thickness (㎛) Friction coefficient Comparative Example 1 - - 0.4786 0.0303 Comparative Example 2 One 10 0.8244 0.0243 Comparative Example 3 5 10 0.7128 0.0267 Comparative Example 4 10 10 0.5592 0.0284 Comparative Example 5 20 10 0.4920 0.0290 Comparative Example 6 50 10 0.4628 0.0320 Comparative Example 7 100 10 0.4558 0.0327 Comparative Example 8 One 20 1.0305 0.0223 Comparative Example 9 5 20 0.9852 0.0247 Comparative Example 10 10 20 0.7915 0.0273 Comparative Example 11 20 20 0.6360 0.0281 Comparative Example 12 50 20 0.6016 0.0289 Comparative Example 13 100 20 0.5980 0.0296 Comparative Example 14 One 30 1.3044 0.0202 Comparative Example 15 5 30 1.2341 0.0211 Comparative Example 16 10 30 1.0773 0.0225 Comparative Example 17 20 30 0.8780 0.0257 Comparative Example 18 50 30 0.7372 0.0271 Comparative Example 19 100 30 0.7013 0.0282 Comparative Example 20 One 40 1.6133 0.0169 Comparative Example 21 5 40 1.5284 0.0181 Comparative Example 20 10 40 1.3981 0.0197 Comparative Example 21 20 40 1.2363 0.0217 Comparative Example 22 50 40 1.0951 0.0223 Comparative Example 23 100 40 1.0503 0.0247 Experimental Example 1 One 50 1.8413 0.0132 Experimental Example 2 5 50 1.7891 0.0145 Comparative Example 24 10 50 1.6458 0.0157 Comparative Example 25 20 50 1.4385 0.0187 Comparative Example 26 50 50 1.2814 0.0223 Comparative Example 27 100 50 1.2409 0.0239 Experimental Example 3 One 60 1.9142 0.0127 Experimental Example 4 5 60 1.8269 0.0139 Experimental Example 5 10 60 1.6822 0.0148 Comparative Example 28 20 60 1.4897 0.0173 Comparative Example 29 50 60 1.3308 0.0186 Comparative Example 30 100 60 1.2791 0.0217

Table 1 shows the results of Experiment 1.

In describing the minimum oil film thickness (MOFT) defined in the theory of fluid lubrication, if the film thickness is too small above the reference value, direct contact between the mating surfaces will occur, which will increase the coefficient of friction and furthermore, The product stops running, causing a breakdown. On the other hand, if the oil film is formed too thick, the friction is increased by the attraction force of the oil film can not play a role for lubrication. Thus, in general, the thickness of the oil film formed between one surface of the bed 600 of the machine tool 101 and the sliding bearing 500 is required to 1.5 ~ 2.0㎛.

In addition, when the friction coefficient between the one surface of the bed 600 of the machine tool 101 and the sliding bearing 500 is 0.0145 or less, the machining precision and the feed rate are satisfied, so that the friction coefficient is scraped to be 0.0145 or less. Requires.

 As described above, Table 1 shows the minimum thickness and average friction coefficient of the oil film measured while varying the average depth and bearing ratio of the scraping hole 519, respectively.

In Table 1, when the average depth of the scraping holes 519 is in the range of 1 micrometer to 5 micrometers, and the bearing ratio is in the range of 50% to 60%, the minimum thickness of the oil film is relatively thick and the coefficient of friction It can be seen that the relative low.

In particular, when the average depth of the scraping hole 519 is 1 micrometer, and the bearing ratio is 60%, it can be confirmed that the minimum thickness of the oil film is the thickest and the friction coefficient is the lowest. That is, it can be confirmed that Experimental Example 1 to Experimental Example 5 has a friction coefficient that satisfies the processing precision and the feed rate compared with other comparative examples.

On the other hand, if the average depth of the scraping holes 519 is less than 1 micrometer or more than 5 micrometers, and if the bearing ratio is less than 50% or more than 60%, the minimum film thickness decreases or the friction coefficient increases. It can be seen.

Experiment 2 is a comparative example in which the scraping hole 519 is not formed, and the average depth of the scraping hole 519 is 1 micrometer according to an embodiment of the present invention, and the bearing ratio of the bearing plate 510 is measured. In contrast to the 60% experimental example, the minimum film thickness and the friction coefficient were measured.

Specification Measures Average Depth (μm) Bearing ratio (%) Oil film thickness (㎛) Friction coefficient Experimental Example One 60 1.9142 0.0127 Comparative example No scraping holes 0.4786 0.0303

Table 2 shows the results of Experiment 2. In the experimental example and the comparative example, there is a difference in bearing ratio depending on the presence of the scraping hole 519 and the presence of the scraping hole 519.

As shown in Table 2, the experimental example was reduced by 50% or more friction coefficient compared to the comparative example, it can be seen that the minimum film thickness is increased by more than four times.

As such, it was confirmed through Experiment 1 and Experiment 2 that the sliding bearing 500 of the machine tool 101 according to the embodiment of the present invention can effectively reduce friction between the bed 600 and the bed 600.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. will be.

Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

101: machine tool 200: table
300: spindle 400: slider
500: sliding bearing 510: bearing plate
519: scraping hole 580: oil groove
600: bed 650: linear guided motion

Claims (4)

Bed;
A slider mounted on the bed in a linear reciprocating manner; And
Sliding bearing (sliding bearing) installed on one surface of the slider facing the bed
Including;
The sliding bearing,
Bearing plate;
An oil groove formed on one surface of the bearing plate facing the bed to supply lubricating oil; And
A plurality of scraping holes formed on one surface of the bearing plate
Including;
The average depth of the scraping holes is in the range of 1 micrometer to 5 micrometers,
Machine tool characterized in that the ratio of the bearing area (Bearing Ratio) of the bearing plate and the bed to the total area of the bearing plate falls within the range of 50% to 60%. In claim 1,
A machine tool having an inclined surface opposite the bed of the bearing plate, the thickness of which is the entirety of the bearing plate. delete delete

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