Method for manufacturing an arm-like structure and arm-like structure

Abstract

Provided is a manufacturing method of an arm-like structure (1) capable of manufacturing an arm-like structure (1) that is sufficiently thin-walled and light-weight compared to casting, and an arm-like structure (1). The method includes the steps of: in a state where a mold having a pipe (2) made of metal disposed inside a cavity is closed, supplying a liquid to the inside of the pipe (2) and pressurizing it, thereby pushing the outer surface of the expanded pipe (2) against the inner surface of the cavity, thereby molding an arm precursor having the outer shape of the arm-like structure (1); and manufacturing the arm-like structure (1) by forming a flange portion (4) for mounting to a driven body by machining at least one end of the molded arm precursor.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an arm-shaped structure and to the arm-shaped structure itself. Background Technology

[0002] Generally, industrial robot arms are constructed from cast metals such as aluminum alloys to achieve lightweight yet maintain strength (see, for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-018058 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In metal casting, a cavity of minimum thickness is required to ensure the flow of the molten metal, and the resulting castings are difficult to achieve sufficiently thin walls. Therefore, it is desirable to manufacture an arm-shaped structure that achieves sufficient thin walls and is lightweight compared to the casting process.

[0008] Solution for solving the problem

[0009] One aspect of the present invention is a method for manufacturing an arm-shaped structure, the method comprising the following steps: with a mold in which a metal tube is disposed within a cavity closed, supplying liquid into the interior of the tube and pressurizing it, thereby pushing the outer surface of the expanded tube against the inner surface of the cavity, thereby forming an arm-shaped precursor component having the shape of an arm-shaped structure; and manufacturing the arm-shaped structure by machining at least one end of the formed arm-shaped precursor component to form a flange portion for mounting to a driven body. Attached Figure Description

[0010] Figure 1 This is a perspective view showing an example of an arm-shaped structure manufactured using a method for manufacturing an arm-shaped structure according to an embodiment of the present invention.

[0011] Figure 2 It shows the manufacturing process. Figure 1 A longitudinal sectional view of the raw material of the first shape of the arm-shaped structure.

[0012] Figure 3 It shows the manufacturing process. Figure 1 A longitudinal sectional view of the first intermediate component of the second shape formed during the manufacturing process of the arm-shaped structure.

[0013] Figure 4 Yes Figure 1A longitudinal sectional view illustrating the first mold in its open state used in the manufacturing method of the arm-shaped structure.

[0014] Figure 5 It is shown Figure 4 A longitudinal sectional view of the first mold in the closed state.

[0015] Figure 6 It is shown Figure 5 A longitudinal sectional view of the cavity of the first mold containing the raw materials.

[0016] Figure 7 It is for use Figure 4 A longitudinal sectional view illustrating the bulging and bending process of the first mold.

[0017] Figure 8 Yes, it has been replaced. Figure 4 A longitudinal sectional view illustrating the bulging and bending process of the upper moving mold of the first mold.

[0018] Figure 9 To use Figure 4 A longitudinal sectional view illustrating the state in which the two ends of the first intermediate part, formed by the bulging and bending process of the first mold, are cut off.

[0019] Figure 10 It is to be by Figure 9 A longitudinal sectional view illustrating the bulging molding process in which the formed second intermediate component is housed within the cavity of the second mold.

[0020] Figure 11 It is in Figure 10 A longitudinal sectional view illustrating the state in which the second intermediate component expands due to bulging molding within the cavity of the second mold.

[0021] Figure 12 It is through Figure 11 A longitudinal sectional view illustrating the state where the two ends of the third intermediate component, obtained through bulging and forming, have been cut off.

[0022] Figure 13 It is in the Figure 12 A longitudinal sectional view illustrating the bending process of the flanges formed at both ends of the molded third intermediate component.

[0023] Figure 14 It is shown in the form of Figure 13 It is formed by drilling holes in the shaped flange and creating working openings on both shoulders. Figure 1 A longitudinal sectional view of the arm-shaped structure.

[0024] Figure 15 It is shown Figure 1 A longitudinal sectional view of a modified example of an arm-shaped structure.

[0025] Figure 16 It is shown Figure 1 An enlarged perspective view of another variation of the arm-shaped structure.

[0026] Figure 17 It is shown Figure 1 An enlarged longitudinal sectional view of another variation of the arm-shaped structure.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1: Arm-shaped structure

[0029] 2: Tubular section (pipe material)

[0030] 4: Flange portion

[0031] 5: Central hole

[0032] 7: Openings for work

[0033] 8: Reinforced components

[0034] 21: Raw materials

[0035] 22: First intermediate component (raw material)

[0036] 23: Second intermediate component (raw material)

[0037] 24: Third intermediate component

[0038] 25: Arm Front Drive Component

[0039] 26: Opening

[0040] 30: First mold

[0041] 31: Cavity

[0042] 40: Second mold (mold)

[0043] L, M: Liquid

[0044] X: Pre-determined distance Detailed Implementation

[0045] The following description, with reference to the accompanying drawings, will illustrate an arm-shaped structure 1 according to one embodiment of the present invention and a method for manufacturing the arm-shaped structure 1.

[0046] The manufacturing method of the arm-shaped structure 1 in this embodiment is, for example, manufacturing... Figure 1 The method for the arm-shaped structure shown.

[0047] The arm-shaped structure 1 of this embodiment is integrally constructed from a metal such as aluminum alloy, and the arm-shaped structure 1 is, for example, a robotic arm. The arm-shaped structure 1 has a pair of annular flange portions 4 at both ends of a tubular portion (tube) 2 with a smoothly varying cross-sectional shape. The pair of flange portions 4 each have a flange surface 3 disposed on the same plane parallel to the central axis of the tubular portion 2.

[0048] The flange portion 4 has a central hole 5 with a central opening, and also has a plurality of through holes 6 arranged circumferentially spaced around the central hole 5. The central hole 5 of the flange portion 4 communicates with the hollow portion inside the tubular portion 2. Thus, cables and other linear elements can be routed through the tubular portion 2 via the central hole of one flange portion 4 and along a path taken out from the central hole 5 of the other flange portion 4.

[0049] By fastening bolts through multiple through holes 6 provided on the flange portion 4 to other components (driven bodies) constituting the robot, such as the output shaft of the reducer, the arm-shaped structure 1 can be easily fixed to the reducer.

[0050] An opening 7 for working is provided on the arm-shaped structure 1. The opening 7 is formed by cutting away the shoulder (wall) opposite to the flange 4 in the direction of the central axis of the flange 4. Through the opening 7, bolt tightening and wiring operations can be easily performed.

[0051] The manufacturing method of the arm-shaped structure 1 of this embodiment will be described below.

[0052] The manufacturing method of the arm-shaped structure 1 in this embodiment first prepares... Figure 2 The straight tubular raw material 21 shown is bent by using the expansion forming process of the first mold 30 to form... Figure 3 The crank-shaped (second shape) first intermediate component (raw material) 22 shown.

[0053] For example, such as Figure 4 As shown, the first mold 30 includes an upper mold 32 and a lower mold 33, which define a cylindrical cavity 31. The cavity 31 is capable of accommodating a straight tubular raw material 21 and extends in the horizontal direction. Additionally, the first mold 30 includes a plunger 34 and a rod 35. The plunger 34 is inserted into the cavity 31 from one end and is supported to be movable in the longitudinal direction of the cavity 31. The rod 35 is inserted into the cavity 31 from the other end and is movable in the longitudinal direction.

[0054] The upper die 32 and the lower die 33 can be divided by horizontal dividing surfaces 32a and 33a that include the central axis of the cavity 31. The upper die 32 is provided with an upper moving die 36 that can be raised and lowered at the central position in its length direction. The lower die 33 is also provided with a lower moving die (punch) 37 that can be raised and lowered at the central position in its length direction.

[0055] like Figure 5 As shown, with the upper moving mold 36 relative to the upper mold 32 and the lower moving mold 37 relative to the lower mold 33 respectively moved to positions forming a cylindrical cavity 31, the dividing surfaces 32a and 33a of the upper mold 32 and the lower mold 33 are brought into close contact, and a portion of the plunger 34 and the rod 35 are positioned between the upper mold 32 and the lower mold 33. Thus, a cylindrical cavity 31 is formed between the upper mold 32 and the lower mold 33, capable of precisely accommodating the straight tubular raw material 21.

[0056] The plunger 34 is formed into a cylindrical shape that fits perfectly into the cavity 31 in this state, and can move along the length direction within the cavity 31 while applying pressure to one end of the raw material 21 in the axial direction.

[0057] The rod 35 is also formed into a cylindrical shape that fits perfectly into the cavity 31 in this state, and can move along the length direction within the cavity 31 while applying pressure to the other end of the raw material 21 in the axial direction.

[0058] A through hole 35a extending along the length of the rod 35 is provided. By connecting this through hole 35a to a pipe (not shown), high-pressure liquid L can be supplied from the pipe to the inside of the raw material 21 through the through hole 35a. Alternatively, a through hole can also be provided on the plunger 34, similar to that on the rod 35.

[0059] like Figure 6 As shown, the upper moving mold 36 and the lower moving mold 37 are moved to a state capable of forming the cavity 31, and a straight tubular raw material 21 is accommodated between the upper mold 32 and the lower mold 33, so that the dividing surfaces 32a and 33a of the upper mold 32 and the lower mold 33 are in close contact. Then, plungers 34 and rods 35 are inserted from both ends of the cavity 31, and the front ends of the plungers 34 and rods 35 abut against both ends of the raw material 21. In this state, high-pressure liquid L is supplied and filled into the interior of the raw material 21 through the through hole 35a of the rod 35.

[0060] And, as Figure 7 and Figure 8As shown, the plunger 34 and rod 35 are moved closer to each other, and the upper moving mold 36 and lower moving mold 37 are moved synchronously. This causes the raw material 21 within the first mold 30 to smoothly deform from a first shape into a second shape, forming a first intermediate component (raw material) 22. The second shape is a crank shape formed by keeping the two ends of the raw material 21 of the first shape coaxial and close to each other, and by sliding only the central portion in the length direction vertically upward or downward.

[0061] Furthermore, by replacing the upper moving mold 36 or the lower moving mold 37 during the bulging process, as shown in the example... Figure 8 The mold shown, with an R-shaped surface, can be constructed in a manner similar to... Figure 3 The corner shown is a crank-shaped first intermediate part 22 with a smooth R-surface.

[0062] Next, as Figure 9 As shown, the two ends of the first intermediate part 22 thus formed are cut off, thereby creating a second intermediate part (raw material) 23 that is bent into a U-shape and has two ends that open in the same direction.

[0063] Then, the second intermediate component 23 thus constructed is expanded and shaped using the second mold (mold) 40, thereby forming the third intermediate component 24.

[0064] like Figure 10 As shown, the second mold 40 has an upper mold and a lower mold 43, and two rods 44 and 45. The upper mold and lower mold 43 can form a cavity 41 larger than the outer shape of the second intermediate component 23. The two rods 44 and 45 are disposed at both ends of the cavity 41. Figure 10 and Figure 11 In the middle, the upper mold (not shown) and the lower mold 43 can be stacked in the normal direction of the paper shown in the figure, forming a cavity 41 between them. Additionally, in Figure 10 and Figure 11 In the accompanying drawings, a lower mold 43 is shown, and the upper mold is separated from the lower mold 43 in the direction normal to the paper.

[0065] The cavity 41 of the second mold 40 contains the second intermediate component 23, such as Figure 10 As shown, the second mold 40 is closed, and the rods 44 and 45 are respectively fitted into the two ends of the second intermediate component 23 to seal the two ends, and high-pressure liquid M is supplied to the interior through the through holes 44a and 45a of the rods 44 and 45.

[0066] Then, liquid M is used to pressurize the second intermediate component 23 in the direction of expansion, and rods 44 and 45 are pressed into cavity 41, thereby... Figure 11As shown, the outer surface of the expanded second intermediate component 23 is pressed against the inner surface of the cavity 41. Thus, the third intermediate component 24 is formed.

[0067] Next, as Figure 12 As shown, the two ends of the third intermediate component 24 thus formed are cut off to form an arm forward component 25 with a pair of openings 26 located on a surface parallel to the length direction of the tubular portion 2. Then, as... Figure 13 As shown, both ends of the arm front drive component 25 are bent radially inward once, and then bent radially outward once. This forms an annular flange portion 4 with a central hole 5 protruding inward from each opening 26 of the arm front drive component 25.

[0068] Then, a plurality of through holes 6 are formed at circumferential intervals on the annular flange portion 4. Additionally, the shoulder portion of the arm front drive component 25 opposite the opening 26, i.e., at the position opposite to the central axis of the central hole 5 of the flange portions 4 at both ends, is cut off, thereby... Figure 14 As shown, an opening 7 for operation is formed. This creates... Figure 1 The arm-shaped structure 1 shown.

[0069] Thus, according to the manufacturing method of the arm-shaped structure 1 of this embodiment, the arm-shaped structure 1 is manufactured by expanding the tubular raw materials 21, 22, 23, and 24 through bulging molding. This has the advantage that, compared to casting, it is easier to manufacture arm-shaped structures 1 with thin walls (e.g., a thickness of 2-3 mm) and uniform wall thickness. Furthermore, the above-mentioned bulging molding also includes any processing method such as hot rolling or cold rolling.

[0070] Furthermore, after bending the straight tubular raw material 21 through bulging molding, the crank-shaped tubular second intermediate component 23 is expanded again through bulging molding. Thus, it is possible to manufacture an arm-like structure 1 with a smooth curved surface without steps using a single component. The smooth curved surface is suitable for arm-like structures used in collaborative robots that may be touched by workers.

[0071] Furthermore, since the flange portion 4 is formed to protrude inward from each opening 26 of the arm forward member 25, it is possible to provide an arm suitable for collaborative robots that do not have protrusions on the outside of the arm-shaped structure 1.

[0072] In addition, since the working opening 7 is provided on the wall surface of the arm front member 25 opposite to the opening 26, it can provide an arm with excellent assembly workability, which can perform wiring operations and other similar tasks well.

[0073] Furthermore, in this embodiment, since bulging molding is also used in the method of bending the straight tubular raw material 21 into a crank-shaped tubular form, variations in wall thickness can be suppressed, and bending processing can be performed with a smaller bending radius. Alternatively, when forming the third intermediate part 24 using the second mold 40, the second intermediate part 23, which is formed into a crank-shaped tubular form by other methods, can also be used as raw material.

[0074] Furthermore, the arm structure 1 manufactured in the above manner can be subjected to at least partial heat treatment, such as T6 treatment. This allows for the manufacture of an arm structure 1 made of a thin-walled, lightweight metal with higher strength.

[0075] In addition, in this embodiment, the raw material 21, the first intermediate component 22, the second intermediate component 23, the third intermediate component 24 and the arm forward component 25 may be subjected to heat treatment, which is used to make the material properties and the changes in properties generated during plastic processing into a state suitable for the processing procedure.

[0076] In this embodiment, the flange portion 4 is formed by bending both ends of the arm front drive component 25 radially twice; however, it can also be bent once or three times or more. Alternatively, it can be as follows... Figure 15 As shown, the strength of the flange 4 is improved by using a ring-shaped reinforcing member 8, such as a rivet.

[0077] In addition, in this embodiment, such as Figure 12 and 13 As shown, the flange portion 4 is configured to protrude inward from each opening portion 26. Alternatively, it can be configured to protrude outward from each opening portion 26.

[0078] Furthermore, in this embodiment, an arm-shaped structure 1 having two flange portions 4 is illustrated, but it is not limited to this and can also be applied to an arm-shaped structure 1 having a single flange portion 4. Additionally, a case with a flange surface 3 parallel to the length direction of the arm-shaped structure 1 is illustrated, but it is also applicable to a case with a flange portion 4 extending in a direction intersecting the length direction of the arm-shaped structure 1.

[0079] In addition, in this embodiment, such as Figure 16 As shown, a reinforcing rib 9 may also be provided, which spans the back side of the mounting surface of the flange 4 and the inner surface of the wall at both ends of the tubular portion 2. Specifically, the inner surface of the wall is the inner surface between the working opening 7 and the flange 4. This allows for a more secure fixation of the tubular portion 2 and the flange 4.

[0080] Furthermore, in this embodiment, as a flange portion, such as Figure 13As shown, an example is a flange formed by bending both ends of the arm front drive component 25 radially outward and bringing them into contact with the opposing surface. Alternatively, it can be as follows: Figure 17 As shown, the flange portion is formed by bending both ends of the arm front drive component 25 radially outward and separating them from the opposing surface by a predetermined distance X. Therefore, when the arm-shaped structure 1 is installed to other components using bolts passing through the through hole 6, the aforementioned distance X can be shortened as the bolts are tightened, and the flange portion 4 has the same anti-loosening function as a spring washer.

Claims

1. A manufacturing method of an arm-like structure for a collaborative robot having a smooth curved surface shape without steps on a surface, characterized by, including the steps of: In a state where a mold provided with a pipe made of metal in a cavity is closed, a liquid is supplied to the inside of the pipe and is pressurized, whereby the outer surface of the expanded pipe is pressed against the inner surface of the cavity, whereby an arm precursor member having an outer shape of an arm-like structure is molded, wherein the pipe is formed by deforming the shape of the cavity of a first mold provided with a straight pipe-like raw material in the cavity in a state where the first mold is closed, while supplying a liquid to the inside of the raw material and pressurizing it, so that both ends of the raw material are bent in the same direction to form; A flange portion for mounting to a driven body is formed by processing at least one end of the molded arm precursor member, thereby manufacturing the arm-like structure in which one pipe is deformed and integrally molded.

2. The arm-like structure manufacturing method according to claim 1, wherein The flange portion is formed in a ring shape having a central hole by bending the end portion of the arm precursor member in the radial direction one or more times over the entire circumference.

3. The arm-like structure manufacturing method according to claim 2, wherein The flange portion is formed by bending the end portion of the arm precursor member toward the radial inner side.

4. The arm-like structure manufacturing method according to claim 2, wherein The flange portion is constituted by joining the bent end portion of the arm precursor member to a ring-like reinforcing member.

5. The arm-like structure manufacturing method according to any one of claims 1 to 4, wherein The arm-like structure is provided with a reinforcing rib that spans the back surface of the mounting surface of the flange portion and the inner surface of the wall surface of the arm precursor member or the arm-like structure.

6. The arm-like structure manufacturing method according to claim 1, wherein A work opening is formed by cutting a portion of the wall surface of the arm precursor member or the arm-like structure.

7. The arm-like structure manufacturing method according to any one of claims 1 to 4, wherein Heat treatment for improving strength is performed on at least a portion of the arm-like structure.

8. The arm-like structure manufacturing method according to any one of claims 1 to 4, wherein Heat treatment for making a change in material properties applicable is performed on the arm-like structure.

9. An arm-like structure for a collaborative robot having a smooth curved surface shape without steps on the surface, characterized by, An arm-like structure obtained by the arm-like structure manufacturing method according to any one of claims 1 to 8 is provided with: a tubular portion having a pair of opening portions; and a flange portion provided so as to protrude inward from each of the opening portions of the tubular portion; the pair of opening portions are located on a surface parallel to the length direction of the tubular portion, the tubular portion and the flange portion are integrally molded by deforming one pipe, the flange portion is formed in a state in which the surfaces facing each other are separated by a predetermined distance by bending of the tubular portion, and when the flange portion is mounted to another member, the surfaces separated from each other are brought close to each other.

10. The arm-like structure according to claim 9, wherein a work opening is provided on the wall surface opposite the opening portion of the tubular portion.

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