KR20200097199A - Sheet member for sliding guide surface - Google Patents

Abstract

The present invention provides a sheet material for the sliding guide surface, having excellent abrasion resistance and suppressed distortion. As a sheet member (4) forming the guided surface (4a) in a guide structure of a machine tool (1), the sheet material (4) is a compression processed body of a skive sheet containing polytetrafluoroethylene resin as a main component, and has a sheet thickness of 1.5 to 10% thinner than the same of the skive sheet. In addition, the sheet member (4) is stretched and has a specific gravity of 0.01 to 0.04 larger than the same of the skive sheet.

Description

Sheet member for sliding guide surface {SHEET MEMBER FOR SLIDING GUIDE SURFACE}

The present invention relates to a sheet material for a sliding guide surface of a machine tool used in a structure for guiding a work table of a machine tool or the like.

In a machine tool, it is well known that either or both surfaces of a guide surface guiding a support base of a work and a guide surface guided to the guide surface are guided by sliding. For example, in Patent Document 1, a sheet material of a resin composition containing a fluororesin as a main component is adhered to a guide surface or a guided surface. The sheet member for a sliding guide surface of this machine tool (hereinafter, also referred to as a guide sheet member or sheet member) is processed from a compression molded body into a sheet shape by skiving.

For example, as a guide sheet material, in order to ensure its necessary properties, a sheet material containing a powder of copper or a copper alloy as a main component of a polytetrafluoroethylene (PTFE) resin (refer to Patent Document 2) or , A sheet material containing 70 to 90 mass% of a PTFE resin and 10 to 30 mass% of at least one of polyoxybenzoyl and polyphenylene sulfide (refer to Patent Document 3) is known.

Japanese Unexamined Patent Application Publication No. Hei 3-149147 Japanese Unexamined Patent Application Publication No. 2007-61955 Japanese Unexamined Patent Application Publication No. 60-127933

In general, the guide sheet material and the mating sliding surface are lubricated with oil, and the surface of the guide sheet material is subjected to a scraping process for high-precision surface contact with the mating sliding surface. The concave portion formed by the scraping process serves as an oil pocket, whereby lubricant is supplied between the sliding guide surfaces. However, when cutting powder such as metal is generated by the actual operation of the machine tool and the cutting powder is mixed between the sliding guide surfaces, the abrasion of the resin guide sheet material is accelerated, and the life of the sheet material that was originally predicted will be significantly shortened. There is concern. Therefore, in the market, there is a demand for further improvement of the wear resistance of the guide sheet member.

In addition, the conventional guide sheet material is made of PTFE resin with very low fluidity, but contains copper alloy powder having a specific gravity of at least twice that of PTFE resin. In some cases, distortion may occur in the sheet material subjected to the brazing process. Specifically, when the sheet material is stretched in the skyve direction, wave-like undulations (non-flatness) occur near both sides of the sheet, or curved toward either side of the long direction in the plane (non-straightness ), and the width direction curved in a U-shape (non-planarity). As for the sheet material in which the distortion has occurred in the shape as described above, a portion without distortion is cut out and used, or a portion where the distortion is not affected by product function is cut out and used. In most cases, the vicinity of both sides where the distortion has occurred is cut out and used, which is a factor that makes it difficult to reduce the price.

The present invention has been made in view of such circumstances, and an object thereof is to provide a sheet member for a sliding guide surface for a machine tool with excellent wear resistance and suppressed distortion.

The sheet material for a sliding guide surface of the present invention is a sheet material for a sliding guide surface that forms a guide surface or a guided surface in a guide structure of a machine tool, and the sheet material for a sliding guide surface is compression processing of a skive sheet containing PTFE resin as a main component. It is characterized in that the sheet thickness is 1.5 to 10% thinner than that of the skive sheet.

The sheet material for sliding guide surfaces is further stretched and has a specific gravity greater than that of the skive sheet by 0.01 to 0.04.

The sheet material for sliding guide surfaces is characterized in that it contains a powder of a non-ferrous metal having a lower hardness than iron.

It is characterized in that the sheet thickness of the sheet material for the sliding guide surface is 0.5 to 2.5 mm.

In the guiding structure of the machine tool, the sheet material for a sliding guide surface is adhered to a substrate to form the guide surface or a guided surface, and at least on the surface of the side to be adhered to the substrate, the adhesive force with the substrate is applied. It is characterized in that a treatment surface capable of bonding to be applied is formed.

Since the sheet material for a sliding guide surface of the present invention is a compression-processed body of a skive sheet containing PTFE resin as a main component, it is excellent in low friction characteristics, and excellent in oil resistance and coolant resistance. In addition, since the sheet thickness is 1.5 to 10% thinner than skive sheet not subjected to compression processing (hereinafter, skive sheet not subjected to compression processing is simply referred to as skive sheet), abrasion resistance can be improved and at the same time. , The distortion of the skive sheet is corrected, and the distortion of the shape can be suppressed.

Since the sheet material is further stretched, the distortion correction effect of the skive sheet is further improved. Further, since the specific gravity is 0.01 to 0.04 higher than that of the skive sheet not subjected to compression processing and stretching processing, the wear resistance is further improved. Further, since the sheet material contains powder of a non-ferrous metal having a lower hardness than iron, abrasion resistance and compression resistance can be imparted to the guide sheet material made of PTFE resin, and excellent properties as a sheet material are obtained.

Since the sheet thickness of the sheet material is 0.5 to 2.5 mm, a shape excellent in straightness, planarity, and flatness is obtained, and a sheet material having no or less distortion of the shape is obtained. In addition, in the sheet material for a guide surface, the sheet thickness with the highest demand is in the range of 1.0 to 1.5 mm. Therefore, it is possible to provide a guide sheet material according to the present invention with improved wear resistance even for a guide sheet material having a low sheet thickness in demand.

In the guiding structure of the machine tool, the sheet material is bonded to the substrate to form a guide surface or a guided surface, and at least the surface of the sheet material on the side to be adhered to the substrate is formed with an adhesive treatment surface that imparts adhesion to the substrate. , It becomes possible to adhere to the substrate with an adhesive.

1 is a schematic cross-sectional view showing an example of a guide structure for a machine tool.
2 is a plan view of the sheet member for a sliding guide surface of the present invention.
Fig. 3 is a schematic diagram of a calender for performing compression processing of skive sheets and the like.
4 is a diagram showing the relationship between the compressibility and the amount of wear of sheet materials of Examples and Comparative Examples.

The sheet material for a sliding guide surface of the present invention will be described based on FIG. 1. 1 is a schematic cross-sectional view showing an example of a guide structure for a machine tool. The guide structure of the machine tool 1 includes a guide surface 3a on the upper surface of the saddle 3 that guides the table 2 as a support for the work piece, and a guided surface guided by sliding contact with the guide surface 3a. And lubricating oil interposed between the guide surface 3a and the guided surface.

The sheet member for a sliding guide surface of the present invention is a sliding member that forms a guide surface or a guided surface, and the sheet member 4 in Fig. 1 is equivalent. In Fig. 1, the lower surface of the sheet member 4 forms the guided surface 4a. In this guiding structure, even if the table 2 moves on the saddle 3, the table itself does not directly contact the guide surface 3a, and the guided surface 4a of the sheet material 4 provided under the table 2 ) Is a structure that slides with the guide surface 3a. The sheet material 4 is adhered and fixed to the table 2 via the adhesive layer 5.

As the adhesive used for the adhesive layer 5, a known adhesive can be suitably used. For example, an epoxy adhesive, a phenol adhesive, a vinyl ether adhesive, a vinyl acetal adhesive, or the like can be used. Among these, it is preferable to use an epoxy-based adhesive such as an N-5 adhesive (trade name manufactured by NTN Corporation) excellent in adhesion, oil resistance, and coolant resistance.

2 shows a plan view of the sheet member 4. As shown in Fig. 2, the sheet member 4 is a rectangular elongated sheet in plan view. The longitudinal direction (X-axis direction) of the sheet material 4 is the skive direction in skiving processing, and the width direction of the sheet material 4 corresponds to the Y-axis direction. The length of the sheet material 4 in the longitudinal direction is, for example, 5 to 50 m, and is appropriately cut and used according to the intended use. The length of the sheet member 4 in the width direction is, for example, 100 to 1000 mm. Further, on one side or both sides of the sheet material, there is formed an adhesion-capable treatment surface subjected to an adhesion-capable treatment for imparting wettability to the PTFE resin and increasing adhesion to the substrate. Examples of the adhesion-enable treatment include corona discharge treatment, sputter etching treatment, plasma etching treatment, surface etching treatment such as ammonia conversion treatment, and ultraviolet irradiation treatment.

The sheet material for a sliding guide surface of the present invention uses a skive sheet obtained by skiving from a compression molded body containing a PTFE resin as a main component as a compact member. Skive processing is a processing method in which a sheet is thinly cut off from the surface of a compression molded body by a lathe.It is a processing widely used for sheet processing of PTFE resin. That's the way. Here, the conventional sheet material for a sliding guide surface has been generally used by subjecting a skive sheet subjected to a skive process to an adhesion-enable process and cutting it into predetermined dimensions. However, in the skyve sheet, when the sheet material is stretched in the skyve direction, it has a wavy undulation (non-flatness) in the vicinity of both sides of the sheet or is curved toward either side of the long direction on the plane (non-straightness ), or a shape that is curved in a U-shape in the width direction (non-planarity) may occur, and there is room for improvement.

In contrast, the sheet material 4 according to the present invention is a compression-processed body in which both sides of the skive sheet are compressed, and the sheet thickness t of the sheet material 4 is 1.5 to 10% thinner than the sheet thickness T of the skive sheet. It is characterized by that. As a result, the density of the sheet increases, the wear resistance is improved, and the distortion of the shape of the skive sheet can be corrected, and a sheet material in which the distortion is suppressed is obtained. If the amount of change in the sheet thickness is less than 1.5%, there is a fear that the effect of improving the abrasion resistance may not be obtained, and if it exceeds 10%, there is a fear that the distortion of the shape is conversely increased. The amount of change in the sheet thickness is preferably 2 to 10%. For example, when the sheet thickness T of the skive sheet is 1.55 mm, the sheet thickness t of the sheet material 4 is 1.40 to 1.52 mm. The amount of change in the sheet thickness is calculated as the compression ratio (%) by the following equation.

Compression rate = ((Skyve sheet thickness T)-(Sheet material (4) sheet thickness t))/(Skyve sheet sheet thickness T)×100

When the compression ratio exceeds 7%, the effect of improving abrasion resistance reaches a limit point. Therefore, considering the cost effect, the compression ratio is preferably 2 to 7%. More preferably, the compression ratio is 4 to 7%.

It is preferable that the sheet thickness t of the sheet material 4 is 0.50 to 2.50 mm. If the sheet thickness t is less than 0.50 mm, post-processing after bonding the sheet material to the machine tool may be difficult, and if the sheet thickness t exceeds 2.50 mm, the time required for cost increase or correction of distortion This lengthens, and there is a fear that productivity decreases.

Since the sheet material of the present invention is a compression-processed body in which both surfaces of the skive sheet are compressed, the smoothness of both surfaces is increased and the surface roughness is reduced compared to the skive sheet. As an index of the surface roughness, an arithmetic average roughness Ra can be used. For example, the arithmetic average roughness Ra of the skive sheet is 2 to 5 μm, whereas the arithmetic average roughness Ra of the guide sheet material of the present invention is 1 to 3 μm. to be. For example, the Ra of the sheet material of the present invention is about 25% to 50% smaller than that of the skive sheet.

Further, by performing stretching processing simultaneously with compression processing, the effect of correcting the non-linearity, non-flatness, and non-planarity of the sheet is enhanced. Since the density of the sheet material improves after compression processing and stretching processing, the state of the sheet material changes before and after these processing. Before and after compression on both planes, the density rises by 0.01 to 0.04. The density of the sheet material is increased and abrasion resistance is improved by compression processing and stretching processing. In addition, the flatness and flatness of the skive sheet are corrected.

The sheet material 4 is a molded body of a resin composition containing a PTFE resin as a main component. PTFE resin has a low coefficient of friction and is excellent in heat resistance, oil resistance, and coolant resistance.

In the resin composition used for the sheet material 4, it is preferable to contain a powder of a non-ferrous metal having a lower hardness than iron. In the case of using a powder of a non-ferrous metal having a lower hardness than iron, the relative sliding surface of the sheet material (the guide surface 3a of the saddle 3 in Fig. 1) is usually composed of a ferrous metal such as a casting, and the relative sliding surface thereof is This is to prevent wear. Further, by including the powder of a non-ferrous metal having a lower hardness than iron, abrasion resistance and compression resistance can also be imparted to the sheet material 4.

Moreover, it is preferable that the said non-ferrous metal powder contains 35-60 mass% with respect to the whole said resin composition. If the content of the non-ferrous metal powder is less than 35% by mass, it is difficult to significantly improve the strength (e.g., strength on the creep surface) and abrasion resistance, and if it exceeds 60% by mass, the low friction characteristics of the PTFE resin will be impaired. Because there is concern. Therefore, by making the content of the non-ferrous metal powder within the above range, it is possible to improve the strength and abrasion resistance without impairing the low friction characteristics of the PTFE resin, making it difficult to cause creep deformation, thereby preventing a decrease in guiding accuracy. . Moreover, the content of the non-ferrous metal powder is more preferably 40 to 50% by mass.

As the powder of a non-ferrous metal having low hardness, it is preferable to use a powder of copper or a copper alloy. These powders have an advantage of having a lower hardness than iron, a low coefficient of friction among non-ferrous metals, low cost, and easy processing. Since the copper alloy is a copper alloy composed of copper and tin or copper and zinc, it does not wear the counterpart, and becomes a sliding member for machine tools that is resistant to high loads.

When using copper or copper alloy powder, it is preferable to set the powder particle diameter of copper or copper alloy to 2 to 150 µm. When the particle diameter exceeds 150 µm, it becomes difficult to uniformly disperse the powder in the PTFE resin due to the large specific gravity of copper or copper alloy, and there is a concern that unevenness or variation in strength and abrasion resistance may occur. Moreover, even if it is less than 2 micrometers, it becomes difficult to uniformly disperse the powder in the PTFE resin. In addition, the particle diameter can be measured using, for example, a particle diameter distribution measuring apparatus using a laser light scattering method.

From the above, a resin composition containing copper or a copper alloy as a powder of a non-ferrous metal in the PTFE resin as the main component is preferable. In addition, when the content of copper or copper alloy powder is 35 to 60% by mass, strength and abrasion resistance can be improved without impairing the low friction characteristics of the PTFE resin, making it difficult to cause creep deformation, thereby reducing the guide accuracy. Can be prevented. Further, by setting the powder particle size of copper or copper alloy to 2 to 150 µm, the powder can be uniformly dispersed in the PTFE resin to make the strength and abrasion resistance uniform.

As described above, the guide sheet material of the present invention is a compression processed body in which both planes of the PTFE resin sheet obtained by skiving are compressed. Specifically, it is obtained by compressing and stretching a skive sheet. This processing method will be described based on FIG. 3. 3 is a schematic diagram of a calender that performs compression processing or the like. The calender 11 includes an unwinding roller 12 for supplying a skive sheet S, a heating roller 13 for heating and compressing the skive sheet, and a water cooling roller 14, It has a winding roller (15) for winding the sheet material after processing. The skive sheet S is sent from the take-up roller 12 in the direction of the arrow, and is wound around the take-up roller 15 via a heating roller and a water cooling roller.

The compression processing is performed by the heating roller 13 made of a pair of rollers (upper roller 13a and lower roller 13b). The skive sheet S passes between the heated upper and lower rollers and is sandwiched between these rollers, whereby compression processing is performed. Both rollers are pressed against each other. The load between rollers also depends on the sheet thickness of the skive sheet, but is, for example, 1 to 10 kN, and preferably 3 to 6 kN. Moreover, it is preferable that the surfaces of both rollers are formed smoothly and that the surface roughness is Ra = 0.01 to 0.10 µm.

It is preferable that the upper and lower two rollers 13a and 13b are heated to a temperature lower than the melting point of the PTFE resin, more preferably exceeding the glass transition temperature of the PTFE resin, and more preferably lower than the melting point. However, since there is a possibility of discoloration due to heating of the PTFE resin skive sheet, it is necessary to set the temperature to a level that does not discolor. By heating the upper and lower two rollers to a temperature lower than the melting point of the PTFE resin, the sheet material after compression processing can be prevented from returning to the distorted shape of the small material, and flatness and flatness are improved. The temperature of the heating roller 13 is preferably 150 to 250°C, more preferably 180 to 230°C.

The stretching process is performed by applying tension to the skive sheet S (winding-side sheet) and the compressed sheet S'(winding-up side sheet), respectively, with a boundary between the upper and lower rollers. As in the calender 11 of Fig. 3, the skive sheet S unwound from the unwinding roller 12 is sandwiched between the rollers of the upper roller 13a and the lower roller 13b, and at the same time, the upper roller Since it is in close contact with about 1/2 of the surface of (13a), it is possible to control the unwinding tension applied to the unwinding-side sheet by controlling the rotation torque of the unwinding roller 12. In addition, since it is sandwiched between the rollers of the upper roller 13a and the lower roller 13b and is in close contact with about 1/2 of the surface of the lower roller 13b, the rotation torque of the take-up roller 15 is controlled. By doing so, it is possible to control the winding tension applied to the winding-side sheet. The unwinding tension and the winding tension are, for example, 300 to 1000 N.

By applying tension to the unwinding-side sheet, the shape of the skive sheet when passing between the heating rollers becomes flat, and the flatness and flatness of the sheet S'corrected by compression processing become excellent. By applying tension to the take-up-side sheet, the shape of the compression-processed sheet S'can be further corrected, and the straightness is excellent. In addition, a sheet material with high degree of completion can be obtained because wrinkles do not occur.

The sheet S'which has passed between the heating rollers 13 is cooled by the water cooling roller 14 and wound up by the take-up roller 15. The wound sheet is a sheet material according to the present invention. As described above, the skive sheet is subjected to compression processing with two heating rollers on the top and bottom with a smooth surface, and stretching processing to which a predetermined tension is applied, so that the abrasion resistance is excellent, and there is no distortion or distortion of the shape. It becomes less sheet material.

[Example]

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

A raw material powder (resin composition) containing 55% by mass of a PTFE resin and 45% by mass of a copper-tin alloy powder was compression molded under predetermined conditions and fired to produce a cylindrical compression molded body (billet) made of a PTFE resin. This billet was attached to a skyve lathe, and skive sheet having a sheet thickness of 1.55 mm, a length in the width direction of 330 mm, and a length in the longitudinal direction of 25 m was obtained by skiving processing. This skive sheet was subjected to compression processing and stretching processing under the processing conditions shown in Table 1 using the calender shown in Fig. 3 (hereinafter, collectively referred to as calender processing), and Examples 1 to 3 and Comparative Examples 1 to 2 The sheet material of was obtained. About the obtained sheet material, wear resistance evaluation and shape change evaluation were performed. As the sheet material of Comparative Example 3, a skive sheet, that is, a sheet material to which compression processing and stretching processing have not been performed, was used.

(1) Wear resistance evaluation

Using the calendered sheet material (Examples 1 to 3 and Comparative Examples 1 to 2) and the unprocessed sheet material (Comparative Example 3), a reciprocating test was performed, and abrasion resistance evaluation of each sheet material was performed. The conditions for the reciprocating movement test were 0.5 MPa surface pressure, 10 m/min sliding speed, and oil lubrication. The amount of wear after 25 hours operation of the reciprocating test was measured. The amount of abrasion was calculated as the average value of the abrasion depth at three places of the sheet material. Table 1 shows the amount of wear, and Fig. 4 shows the relationship between the amount of wear and the compression rate.

From Table 1, the abrasion amount of the raw sheet material (Comparative Example 3) is about 10 μm, whereas the sheet material (Examples 1 to 3) according to the present invention has a wear amount of about 6 to 7 μm, and abrasion resistance of 30 to 40% The improvement was recognized. In addition, from the relational diagram of Fig. 4, it was found that when the compression ratio was 1.5% or more, the effect of improving abrasion resistance was obtained, while the change in the amount of wear reached the limit even when the compression ratio was higher than 7%.

(2) shape change evaluation

Specific gravity was measured for each sheet material. As a result, relative to the unprocessed sheet material (Comparative Example 3), the sheet materials (Examples 1 to 3) according to the present invention had a specific gravity of 0.01 to 0.04 large. Specifically, the sheet material of Example 1 had a specific gravity of 3.39, the sheet material of Example 2 had a specific gravity of 3.40, the sheet material of Example 3 had a specific gravity of 3.42, and the sheet material of Comparative Example 3 had a specific gravity of 3.38.

For each sheet member, flatness, planarity, and straightness were evaluated in the state that the sheet member was stretched in the longitudinal direction. The flatness represents the degree of wave needles (wave-shaped undulations) caused by bending (bending) in the height direction at arbitrary intervals in the longer direction of the width direction, and the height of the wave needles with a convex It evaluated by measuring. The planarity indicates the degree of a U-shaped shape in the width direction generated by bending both edges in the width direction in the height direction, and was evaluated by measuring the depth of the concave portion at the substantially central portion in the width direction with a convex. Straightness indicates the degree to which the entire shape in the long direction is curved in a substantially fan shape, and was evaluated using a tape measure. Specifically, the gap between the tape measure and the edge of the approximately central part of the long direction was measured in a state where the tape measure was affixed to the edge of one piece in the long direction of the sheet material. As a result, the sheet material according to the present invention (Examples 1 to 3) has a flatness of about 1/15 to 1/20 and a straightness of about 1/20 to 1/ relative to an unprocessed sheet material (Comparative Example 3). 30, the planarity was about 1/15 to 1/18, and the shape distortion of the raw sheet material almost disappeared or decreased remarkably.

In this way, the sheet material whose sheet thickness is 1.5 to 10% thinner than the sheet thickness of the skive sheet by calendering has a productivity of 125 to 140% compared to the skive sheet (the conventional sheet material for guide surfaces not subjected to calendar processing). Was admitted.

The sheet material for a sliding guide surface of the present invention is excellent in wear resistance and at the same time, since distortion is suppressed, it is possible to reduce portions to be removed by distortion, thereby improving productivity, and is widely used as a sheet material for a sliding guide surface for a machine tool. Can be used.

1: machine tool
2: table
3: birds
4: sheet materials
5: adhesive layer
11: calender
12: unwinding roller
13: heating roller
14: water cooling roller
15: winding roller
S: skyve sheet
S': Sheet (sheet material for sliding guide surfaces)

Claims (5)

As a sheet material for a sliding guide surface forming a guide surface or a guided surface in a guide structure of a machine tool,
The sheet material for a sliding guide surface is a compression-processed body of a skive sheet containing polytetrafluoroethylene resin as a main component, and the sheet material for a sliding guide surface is 1.5 to 10% thinner than the skive sheet. The method of claim 1,
The sheet member for a sliding guide surface is further stretched and has a specific gravity of 0.01 to 0.04 larger than that of the skive sheet. The method according to claim 1 or 2,
The sheet material for a sliding guide surface, characterized in that it contains powder of a non-ferrous metal having a lower hardness than iron. The method according to any one of claims 1 to 3,
A sheet material for a sliding guide surface, characterized in that the sheet thickness of the sheet material for a sliding guide surface is 0.5 to 2.5 mm. The method according to any one of claims 1 to 4,
In the guide structure of the machine tool, the sheet material for the sliding guide surface is bonded to the base material to form the guide surface or the guided surface, and at least the surface on the side to be adhered to the base material can be bonded to impart adhesive force with the base material. A sheet material for a sliding guide surface, characterized in that the surface to be treated is formed.

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