Flat bellows

Abstract

Provided is a flat bellows having dust resistance, heat resistance, chemical resistance, durability, and flexibility without going through a complicated manufacturing process with a small number of parts. 【Solution means】The flat bellows 1 of a thin metal plate of the present invention is a flat bellows 1 of a thin metal plate that is continuous in a corrugated shape and includes a mountain-folded mountain-folded portion 11, a valley-folded valley-folded portion 12, and an inclined portion 13 that connects the mountain-folded portion 11 and the valley-folded portion 12. The mountain-folded portion 11 has a first mountain-folded side surface 11a and a second mountain-folded side surface 11b that are connected by an arc-shaped top portion 11c. The valley-folded portion 12 has a first valley-folded side surface 12a and a second valley-folded side surface 12b that are connected by an arc-shaped bottom portion 12c. The mountain-folded portion 11 and the inclined portion 13 are connected at an obtuse angle, and the inclined portion 13 and the valley-folded portion 12 are connected at an obtuse angle.

Description

Technical Field

[0001] The present invention relates to a flat bellows for a thin metal plate that prevents chips and the like generated during machining of a workpiece from entering the openings, rails, etc. of a machine tool.

Background Art

[0002] A bellows is an important part that improves the performance and durability of machine tools such as machining centers, grinding machines, and welding machines. The main functions of the bellows are, first, a dust-proof function. The bellows prevents dust from entering the moving parts of the machine and extends the life of the machine. Next is the shock-absorbing function. The bellows absorbs external shocks and protects the internal structure of the machine. And it is a heat- and chemical-resistant function. A bellows made of a special material has resistance to high temperatures and chemicals and can be used even in harsh environments. In addition to these functions, the bellows needs to have flexibility to expand and contract according to the movement of the machine.

[0003] As a bellows having the above-described functions, Patent Document 1 discloses a cloth flat bellows for protecting the sliding surfaces of the bed of a grinding machine and other machine tools from high-temperature chips. The technique described in Patent Document 1 enhances heat resistance by forming a metal layer on the cloth bellows. Specifically, a vinyl-based resin such as vinyl chloride or vinylidene chloride, or an ethylene-based resin such as trifluoroethylene or tetrafluoroethylene is applied to one side of a cloth made of cotton, hemp, synthetic fiber, etc. to form a water- and oil-resistant layer, and a polyester resin or a polyurethane resin is applied to the other side of the cloth to form a water- and oil-resistant cured layer that moderately cures the cloth. Further, a metal layer of aluminum, magnesium, iron, copper, etc. is formed on such a cured layer to improve the heat resistance and oil resistance of the bellows.

[0004] And the bellows described in Patent Document 1 is provided with corrugated reinforcing bars or a link mechanism provided in a fork shape in the main body of the cloth bellows in order to form and maintain the corrugated shape of the bellows.

Prior Art Documents

Patent Documents

[0005] Japanese Utility Model Publication No. 40-024626 Japanese Utility Model Publication No. 40-024626 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] The flat bellows made of cloth described in Patent Document 1 forms a heat-resistant layer, an oil-resistant layer, and a metal layer on the surface of the cloth. However, the formation process of such a metal layer is very complicated and takes a great deal of time for production. In addition, the cloth bellows described in Patent Document 1 requires a large number of parts for forming a reinforcing bar or a link mechanism to maintain the corrugated shape and posture of the bellows, and there is a problem that the production cost increases.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a flat bellows having dust-proofness, heat resistance, chemical resistance, durability, and flexibility without going through a complicated production process with a small number of parts. MEANS FOR SOLVING THE PROBLEMS

[0008] The flat bellows of a thin metal plate of the present invention is a flat bellows of a thin metal plate continuous in a waveform having a mountain-folded mountain-folded portion, a valley-folded valley-folded portion, and an inclined portion connecting the mountain-folded portion and the valley-folded portion. The mountain-folded portion has a first mountain-folded side surface and a second mountain-folded side surface connected by an arc-shaped top portion, the valley-folded portion has a first valley-folded side surface and a second valley-folded side surface connected by an arc-shaped bottom portion, the mountain-folded portion and the inclined portion are connected at an obtuse angle, and the inclined portion and the valley-folded portion are connected at an obtuse angle. EFFECTS OF THE INVENTION

[0009] According to the flat bellows made of a thin metal sheet of the present invention, by forming it by bending the thin metal sheet, it is possible to maintain the shape of the bellows alone, and it is possible to manufacture a flat bellows excellent in heat resistance with a small number of parts and man-hours. Further, since the inclined portion and the mountain fold portion, and the inclined portion and the valley fold portion form an obtuse angle, the angular displacement between the top and the bottom during the expansion and contraction of the bellows is suppressed, and the stress concentrated on the top and the bottom can be suppressed, improving the durability of the bellows.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the flat bellows made of a thin metal sheet of the present invention will be described based on each embodiment with reference to the accompanying drawings. The accompanying drawings schematically show the flat bellows, the constituent members of the flat bellows, and the peripheral members of the flat bellows, and the actual dimensions and dimensional ratios of these do not necessarily match the dimensions and dimensional ratios on the drawings. Further, unless otherwise specified, for convenience, the directions such as up and down are represented based on the orientation of the flat bellows made of a thin metal sheet shown in FIG. 1. Redundant explanations will be omitted as appropriate, and the same members may be given the same reference numerals.

[0012] FIG. 1 is a diagram for explaining the usage state of the flat bellows 1 of the thin metal plate of the present invention. The flat bellows 1 is mainly used in a machining center 2 which is a machine tool for cutting. The machining center 2 cuts the workpiece 3 with a cutting tool 5 attached to the tip of a spindle 4 while moving the workpiece 3 in the X direction and the Y direction. As a means for moving the workpiece 3 in the X direction and the Y direction, a ball screw (not shown) is often used. In cutting, chips 6 may scatter around from the cut workpiece 3, and if these chips 6 adhere to the ball screw, it may cause malfunctions and deterioration of accuracy. Therefore, by covering the ball screw with the flat bellows 1, the adhesion of the chips 6 to the ball screw is prevented.

[0013] FIG. 2 is a diagram for explaining the expansion and contraction state of the flat bellows 1 of the present invention. The flat bellows 1 has a shape in which waveforms are regularly repeated, and expands and contracts in accordance with the movement of the machining center 2. The flat bellows 1 expands and contracts between the minimum length (MIN dimension in the figure) and the maximum length (MAX dimension in the figure) that is 10 times or more of the minimum length. In the embodiment of the present invention shown in FIG. 2, a thin stainless steel spring steel is used as the material of the flat bellows 1. The stainless steel spring steel has sufficient repulsive force and resilience as spring characteristics, and can be deformed flexibly in accordance with the movement of the machining center 2. The height dimension (h dimension in the figure) of the flat bellows 1 is appropriately determined in accordance with the dimensions of a ball screw or the like used in the machining center 2.

[0014] The stainless steel spring steel is not easily rusted and has excellent sealing properties and heat resistance. The flat bellows 1 made of the stainless steel spring steel which is a thin metal plate is superior in heat resistance, impact resistance, and chemical resistance compared to bellows made of a combustible fiber material. Therefore, not only in the machining center 2 but also in use in an environment where high-temperature spatter scatters, such as a laser processing machine (not shown), excellent heat resistance, impact resistance, etc. can be exhibited.

[0015] As the material of the spring steel, a thin plate of SUS304 with a thickness of 0.1 mm to 0.3 mm is used. The thin plate of SUS304 is cut and formed into the flat bellows 1 by bending with a hydraulic press twice. By using the thin plate of SUS304 as the material of the flat bellows 1, the flat bellows can be manufactured only by the cutting process and the press process. Therefore, the manufacturing man-hours can be significantly reduced compared with the cloth-made flat bellows. Note that the material of the spring steel is not limited to SUS304, and for the spring steel, in addition to the stainless steel type, iron-based or copper-based materials can also be used. Also, the thickness of the spring steel is not limited to 0.1 mm to 0.3 mm, and it can be appropriately changed according to the usage conditions.

[0016] Fig. 3 shows a perspective view of the flat bellows according to the embodiment of the present invention. As shown in Fig. 3, the flat bellows 1 includes a mountain fold portion 11 and a valley fold portion 12. Here, the mountain fold means a folding method in which the metal thin plate constituting the flat bellows 1 is bent so that the mountain fold ridge line 11d, which is the fold line, comes out to the outside, and the mountain fold portion 11 has a convex shape bulging to the outside. Also, the valley fold means a folding method in which the metal thin plate constituting the flat bellows 1 is bent so that the valley fold ridge line 12d, which is the fold line, is hidden inside, and the valley fold portion 12 has a concave shape recessed to the inside.

[0017] Fig. 4 shows a front view (a) of the flat bellows 1 in an extended state and a front view (b) of the flat bellows 1 in a contracted state according to the embodiment of the present invention. As shown in Fig. 4(a), the mountain fold portion 11 has a first mountain fold side surface 11a, a second mountain fold side surface 11b that forms an acute angle with the first mountain fold side surface 11a, and a top portion 11c that connects the first mountain fold side surface 11a and the second mountain fold side surface 11b in an arc shape. The first mountain fold side surface 11a and the second mountain fold side surface 11b are bent into a mountain fold at about 50 degrees with a hydraulic press. In this embodiment, the top portion 11c is formed in an R shape of about 1 mm instead of a sharp-edge triangular shape. Thereby, since stress concentration can be alleviated compared with a triangular shape close to the sharp edge, early breakage due to metal fatigue can be prevented.

[0018] The valley fold portion 12 has a first valley fold side surface 12a, a second valley fold side surface 12b that forms an acute angle with the first valley fold side surface 12a, and a bottom-like portion 12c that connects the first valley fold side surface 12a and the second valley fold side surface 12b in an arc shape. The first valley fold side surface 12a and the second valley fold side surface 12b are bent into a valley fold at about 50 degrees by a hydraulic press. In this embodiment, the bottom portion 12c is formed in an R shape of about 1 mm instead of a sharp-edge triangular shape. Thereby, since stress concentration can be alleviated as compared with a triangular shape close to the sharp edge, early breakage due to metal fatigue can be prevented.

[0019] The mountain fold portion 11 and the valley fold portion 12 are connected by an inclined portion 13. The inclined portion 13 has a valley fold bending portion 13a at the boundary with the mountain fold portion 11. As described above, the valley fold is a folding method in which the metal thin plate constituting the flat bellows 1 is bent so that the valley fold ridge line 13b, which is the fold line, is hidden inside, and the valley fold bending portion 13a is recessed inside. The valley fold bending portion 13a connects the inclined portion 13 and the mountain fold portion 11 at an obtuse angle. The inclined portion 13 and the second mountain fold side surface 11b are bent and connected into a valley fold at about 145 degrees using a hydraulic press at the valley fold bending portion 13a.

[0020] The inclined portion 13 has a mountain fold bending portion 13c at the boundary with the valley fold portion 12. As described above, the mountain fold is a folding method in which the metal thin plate constituting the flat bellows 1 is bent so that the mountain fold ridge line 13d, which is the fold line, protrudes outside, and the mountain fold bending portion 13c protrudes outside. The mountain fold bending portion 13c connects the inclined portion 13 and the valley fold portion 12 at an obtuse angle. The inclined portion 13 and the first valley fold side surface 12a are bent and connected into a mountain fold at about 145 degrees using a hydraulic press at the mountain fold bending portion 13c to be connected to the inclined portion 13.

[0021] When the flat bellows 1 expands and contracts, in addition to the angular displacement of the mountain-folded portions 11 and valley-folded portions 12, the angles of the valley-folded bent portions 13a and mountain-folded bent portions 13c are also displaced. As a result, the stress concentrated on the top portion 11c and the bottom portion 12c can be alleviated, and the breakage of the top portion 11c and the bottom portion 12c can be suppressed. In this embodiment, the mountain-folded portion 11 and the valley-folded portion 12 are bent at an acute angle of about 50 degrees. Further, the inclined portion 13 is connected to the mountain-folded portion 11 and the valley-folded portion 12 at an obtuse angle of about 145 degrees. However, the bending angle of the flat bellows 1 is not limited to the above angles and can be changed as appropriate.

[0022] Next, the operation of the flat bellows 1 will be described with reference to FIG. 4. As a comparative example, the conventional flat bellows 15 shown in FIG. 5 will also be described. As shown in FIG. 4(a), the flat bellows 1 is manufactured in an extended state. As described above, the flat bellows 1 is formed by cutting a thin metal plate and bending it by a hydraulic press to form the valley-folded bent portions 13a and mountain-folded bent portions 13c at an obtuse angle of about 145 degrees. Further, by bending with a hydraulic press, the top portion 11c and the bottom portion 12c are bent so as to form an acute angle of about 50 degrees. In this embodiment, the top portion 11c and the bottom portion 12c are formed in an R shape with a radius of about 1 mm, and when the flat bellows 1 contracts to the minimum longitudinal dimension, the height dimension of the flat bellows 1 is made to be about 10 cm. As shown in FIG. 4(b), when the flat bellows 1 contracts to the minimum longitudinal dimension, the angles of the valley-folded bent portions 13a and mountain-folded bent portions 13c are displaced from about 145 degrees to about 170 degrees. The displacement width of the angle in the valley-folded connecting portion 13a and the mountain-folded bent portion 13c is about 25 degrees. When the flat bellows 1 contracts to the minimum longitudinal dimension, the angles of the top portion 11c and the bottom portion 12c are displaced from about 50 degrees to about -15 degrees. The displacement width of the angle in the top portion 11c and the bottom portion 12c is about 65 degrees.

[0023] Figure 5(a) shows the flat bellows 15. The flat bellows 15 is bent so that the top 11c and the bottom 12c have an R shape of about 1 mm and the opening angle is about 90 degrees. When it shrinks to the minimum longitudinal dimension, its height dimension becomes about 10 cm. As shown in Figure 5(b), when the flat bellows 15 shrinks to the minimum longitudinal dimension, the mountain fold 16 and the valley fold 17 are displaced in angle from about 90 degrees to about -3 degrees. The displacement width of the angle at the mountain fold 16 and the valley fold 17 is about 93 degrees.

[0024] Comparing the angular displacement due to the expansion and contraction of the flat bellows 15 and the flat bellows 1, the expansion and contraction of the flat bellows 15 is caused by the angular displacement of the mountain fold 16 and the valley fold 17. Therefore, the angular displacement of the mountain fold 16 and the valley fold 17 is about 93 degrees. On the other hand, for the flat bellows 1, since the valley fold bending part 13a and the mountain fold bending part 13c are bent, the angular displacement of the mountain fold 11 and the valley fold 12 is suppressed, and the angular displacement of the mountain fold 11 and the valley fold 12 is about 65 degrees. That is, the angular displacement of the mountain fold 11 and the valley fold 12 accompanying the expansion and contraction of the flat bellows 1 is about 28 degrees smaller than that of the flat bellows 15. By suppressing the angular displacement width, the stress concentrated on the top 11c and the bottom 12c is relieved, and the durability of the flat bellows 1 is improved.

[0025] The flat bellows 1 can be manufactured with a small number of parts and man-hours using press working of a thin metal plate. Also, since it is made of metal, it can maintain its shape as a single bellows and has excellent heat resistance. Furthermore, the stress concentrated on the top 11c and the bottom 12c can be relieved, and the durability of the flat bellows 1 is improved.

Description of reference numerals

[0026] 1 Flat bellows 2 Machining center 3 Workpiece 4 Spindle 5 Cutting tool 6 Chips 11 Mountain fold 11a First mountain fold side 11b Second mountain fold side 11c Top 11d Mountain fold ridge line 12 valley fold 12a first valley fold side 12b second valley fold side 12c bottom 12d valley fold ridge line 13 inclined part 13a valley fold bending part 13b valley fold ridge line 13c mountain fold bending part 13d mountain fold ridge line 15 flat bellows 16 mountain fold 17 valley fold

Claims

1. A flat bellows made of a continuous corrugated thin metal sheet, comprising a mountain-folded portion that is mountain-folded at an arc-shaped top, a valley-folded portion that is valley-folded at an arc-shaped bottom, and an inclined portion that connects the mountain-folded portion and the valley-folded portion, wherein the mountain-folded portion has a first mountain-fold side surface that is a flat surface and a second mountain-fold side surface that is a flat surface connected to the first mountain-fold side surface at the arc-shaped top, the valley-folded portion has a first valley-fold side surface that is a flat surface and a second valley-fold side surface that is a flat surface connected to the first valley-fold side surface at the arc-shaped bottom, and the mountain-folded portion and the inclined portion are connected at an obtuse angle, and the inclined portion and the valley-folded portion are connected at an obtuse angle. A flat bellows made of a thin metal sheet is characterized by this.

2. The flat bellows made of a thin metal sheet according to claim 1, wherein the angle displacement between the top and the bottom during expansion and contraction is suppressed by a valley-fold bending portion at the boundary between the inclined portion and the mountain-folded portion and a mountain-fold bending portion at the boundary between the inclined portion and the valley-folded portion.

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