Grinding method

Abstract

To provide a polishing method which can inhibit polishing bodies from hooking on an inner wall surface of a pipe.SOLUTION: In a polishing method, a polishing tool 10 is used to polish an inner wall surface W1a of a pipe W1. The polishing tool 10 includes: a first sandwiching part 1; a second sandwiching part 2; polishing bodies 3 disposed between the first sandwiching part 1 and the second sandwiching part 2 and sandwiched between the first sandwiching part 1 and the second sandwiching part 2; and approaching means which causes the first and second sandwiching parts 1, 2 to approach each other. The polishing method includes: a step ST1 in which the polishing tool 10 is inserted into the pipe W1 and the polishing bodies 3 are placed near the inner wall surface W1a of the pipe W1; and a step ST2 in which the first and second sandwiching parts 1, 2 are moved close to each other to deform the polishing bodies 3 and thereby cause the polishing bodies 3 and the inner wall surface W1a of the pipe W1 to contact with each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a polishing method, and more particularly to a polishing method for polishing the inner wall surface of a tube using a polishing body. [Background technology]

[0002] Patent Document 1 discloses a polishing tool equipped with an abrasive body. The abrasive body is discharged onto a synthetic resin thread-like core material and hardened to be discretely fixed to the core material. The polishing tool is inserted into the inside of a metal pipe, and the abrasive body is brought into contact with the inner surface of the metal pipe while being deformed to match the dimensions and shape of the inner surface. The elasticity of the abrasive body is then used to apply pressure to the inner surface of the metal pipe while rubbing it, thereby polishing the inner surface of the metal pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-188523 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have discovered the following problems. When such a polishing tool is inserted into the inside of a metal pipe, the polishing body comes into contact with the inner surface of the metal pipe while deforming according to the dimensions and shape of the inner surface of the metal pipe. Therefore, there is a risk that the polishing body will get caught on the inner surface of the metal pipe. If the polishing body gets caught on the inner surface of the metal pipe, the inner surface of the metal pipe cannot be polished sufficiently.

[0005] In view of the above-mentioned problems, an object of the present invention is to provide a polishing method that prevents the polishing body from getting caught on the inner wall surface of a pipe. [Means for solving the problem]

[0006] The polishing method according to the present invention comprises the steps of: A polishing method for polishing an inner wall surface of a pipe using a polishing tool, comprising the steps of: The polishing tool is A first clamping unit; A second clamping portion; a polishing body disposed between the first clamping portion and the second clamping portion and clamped between the first clamping portion and the second clamping portion; and a proximity means (e.g., strings 4, 5, etc.) for bringing the first and second clamping portions closer to each other, inserting the abrasive tool into the tube and positioning the abrasive body adjacent to an inner wall surface of the tube; and a step of bringing the first and second clamping parts close to each other to deform the polishing body so that the polishing body comes into contact with the inner wall surface of the pipe.

[0007] With this configuration, the polishing body disposed near the inner wall surface of the pipe is deformed to bring the polishing body into contact with the inner wall surface of the pipe, and therefore, when the polishing tool is inserted into the pipe, the polishing body does not need to come into contact with the inner wall surface of the pipe, which makes it possible to prevent the polishing body from getting caught on the inner wall surface of the pipe. Effect of the Invention

[0008] The present invention can prevent the polishing body from getting caught on the inner wall surface of the pipe. [Brief description of the drawings]

[0009] [Figure 1] 2 is a schematic diagram showing one step of an example of a polishing method according to the first embodiment. FIG. [Diagram 2] 2 is a schematic diagram showing one step of an example of a polishing method according to the first embodiment. FIG. [Diagram 3] 1 is a cross-sectional view showing an example of a pipe as an object to be polished by the polishing method according to the first embodiment. [Figure 4] 1 is a graph showing surface roughness Sa versus polishing time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. In addition, the following description and drawings are appropriately simplified for clarity of explanation.

[0011] (Embodiment 1) A first embodiment will be described with reference to Figures 1 and 2. Figures 1 and 2 are schematic diagrams showing one step of an example of a polishing method according to the first embodiment.

[0012] Naturally, the right-handed xyz coordinate system shown in Figure 1 and other drawings is for the convenience of explaining the positional relationship of the components. Usually, the z-axis positive direction is vertically upward, and the xy plane is a horizontal plane, which is common among the drawings.

[0013] As shown in FIG. 1, in one example of the polishing method according to the first embodiment, a polishing tool 10 is used to polish an inner wall surface W1a of a pipe W1, which is an object to be polished.

[0014] The grinding tool 10 includes a first clamping portion 1, a second clamping portion 2, a grinding body 3, and strings 4 and 5.

[0015] The first clamping portion 1 and the second clamping portion 2 clamp the polishing body 3. The first clamping portion 1 and the second clamping portion 2 may have a size and mechanical strength required for clamping the polishing body 3. The first clamping portion 1 and the second clamping portion 2 may have a variety of shapes. An example of the first clamping portion 1 and the second clamping portion 2 shown in FIG. 1 is two plate-like bodies. The first clamping portion 1 may have a hole 1a through which the string 4 can pass. The second clamping portion 2 may have a hole 2a through which the string 5 can pass.

[0016] The polishing body 3 is disposed between the first clamping portion 1 and the second clamping portion 2. The polishing body 3 is clamped between the first clamping portion 1 and the second clamping portion 2. The polishing body 3 may have a size that allows it to pass through the tube W1. Specifically, the diameter D3 of the polishing body 3 may be smaller than the inner diameter D1 of the tube W1. When the polishing body 3 receives a predetermined compressive stress, it deforms so as to protrude in a direction perpendicular to the compressive stress. The polishing body 3 is made of a material having a deformable property. The polishing body 3 may be made of a material having mechanical strength and hardness required for polishing the object to be polished. Examples of such materials include elastic materials such as rubber. Such elastic materials may contain an abrasive. When the tube W1 is made of a metal material, the polishing body 3 may be made of an elastic material such as rubber.

[0017] The polishing body 3 has a hole 3a, which penetrates the polishing body 3. The hole 3a may have a cross-sectional area large enough to allow the strings 4 and 5 to pass through at the same time. The polishing body 3 may be one or more. An example of the polishing body 3 shown in Figs. 1 and 2 has three polishing bodies. The polishing body 3 may have various shapes. An example of the polishing body 3 shown in Figs. 1 and 2 is spherical. The polishing bodies 3 shown in Figs. 1 and 2 are arranged in a row between the first clamping portion 1 and the second clamping portion 2.

[0018] The total length of the string 4 is preferably longer than the length L1 of the tube W1. One end 4a of the string 4 is attached to the second clamping unit 2. The string 4 passes through the holes 3a of the polishing body 3. An example of the string 4 shown in FIG. 1 and FIG. 2 passes through all the holes 3a of the three spherical bodies, which are an example of the polishing body 3. If the first clamping unit 1 has a hole 1a, the string 4 may pass through the hole 1a. The first clamping unit 1 is disposed between the one end 4a and the other end 4b of the string 4. When the other end 4b of the string 4 is pulled so as to be separated from the polishing body 3, the one end 4a of the string 4 pulls the second clamping unit 2 toward the polishing body 3. This brings the second clamping unit 2 closer to the first clamping unit 1.

[0019] The total length of the string 5 is preferably longer than the length L1 of the tube W1. One end 5a of the string 5 is attached to the first clamping unit 1. The string 5 passes through the holes 3a of the polishing body 3. An example of the string 5 shown in FIG. 1 and FIG. 2 passes through all the holes 3a of the three spherical bodies, which are an example of the polishing body 3. If the second clamping unit 2 has a hole 2a, the string 5 may pass through the hole 2a. The second clamping unit 2 is disposed between the one end 5a and the other end 5b of the string 5. When the other end 5b of the string 5 is pulled so as to be separated from the polishing body 3, the one end 5a of the string 5 pulls the first clamping unit 1 toward the polishing body 3. This brings the first clamping unit 1 closer to the second clamping unit 2.

[0020] The strings 4 and 5 function as technical proximity means for bringing the first clamping portion 1 and the second clamping portion 2 close to each other.

[0021] (polishing method) Next, a polishing method for polishing the inner wall surface W1a of the pipe W1 to be polished using the polishing tool 10 will be described with reference to FIGS.

[0022] As shown in FIG. 1, the polishing tool 10 is inserted into the pipe W1, and the polishing body 3 is placed near the inner wall surface W1a of the pipe W1 (step ST1). The polishing tool 10 may be inserted into the pipe W1 while extending in the axial direction of the pipe W1 (here, the X-axis direction) and keeping the polishing body 3 away from the inner wall surface W1a of the pipe W1. Specifically, the polishing tool 10 is inserted into the pipe W1 while keeping one of the strings 4 and 5 placed outside the pipe W1. By flowing a fluid, the other of the strings 4 and 5 is passed through the downstream opening of the pipe W1 and is taken out to the outside of the pipe W1. For example, water can be used as the fluid.

[0023] Next, the first clamping part 1 and the second clamping part 2 are brought close to each other, and the polishing body 3 is deformed, so that the polishing body 3 comes into contact with the inner wall surface W1a of the pipe W1 (step ST2). Specifically, the other end 4b of the string 4 is pulled so as to move it away from the polishing body 3, and the other end 5b of the string 5 is pulled so as to move it away from the polishing body 3. As a result, the first clamping part 1 and the second clamping part 2 are brought close to each other. The first clamping part 1 and the second clamping part 2 apply a compressive stress to the polishing body 3, and the polishing body 3 is deformed so as to protrude in a direction perpendicular to the compressive stress. That is, the diameter D3 of the polishing body 3 increases. When the diameter D3 of the polishing body 3 increases to the same size as the inner diameter D1 of the pipe W1, the polishing body 3 comes into contact with the inner wall surface W1a of the pipe W1. The other end 4b of the string 4 and the other end 5b of the string 5 may be further pulled to press the polishing body 3 against the inner wall surface W1a of the pipe W1. Furthermore, the polishing tool 10 may be moved in the pipe W1 to polish the inner wall surface W1a of the pipe W1.

[0024] As described above, the polishing body 3 arranged near the inner wall surface W1a of the pipe W1 is deformed to bring the polishing body 3 into contact with the inner wall surface W1a of the pipe W1. Therefore, when the polishing tool 10 is inserted into the pipe W1 in step ST1, the polishing body 3 does not need to come into contact with the inner wall surface W1a of the pipe W1, so that the polishing body 3 can be prevented from getting caught on the inner wall surface W1a of the pipe W1. In other words, the polishing body 3 can be moved to most of the area of ​​the inner wall surface W1a of the pipe W1. Furthermore, by moving the polishing body 3 while keeping it in contact with the inner wall surface W1a of the pipe W1 after the movement, most of the area of ​​the inner wall surface W1a of the pipe W1 can be polished.

[0025] In addition, in step ST1, the polishing tool 10 may be inserted into the pipe W1 while the polishing body 3 and the inner wall surface W1a of the pipe W1 are spaced apart. In such a case, even if the polishing tool 10 is inserted into the pipe W1, the polishing body 3 does not come into contact with the inner wall surface W1a of the pipe W1 at all. This further prevents the polishing body 3 from getting caught on the inner wall surface W1a of the pipe W1.

[0026] (Examples) 1 and 2 show an example of the pipe W1 extending in a straight line, but the pipe W1 may extend on a virtual curve in a three-dimensional space. The virtual curve may have multiple bends. The pipe W1 is, for example, a cooling circuit or an oil passage. A structure having the pipe W1 extending on a virtual curve in a three-dimensional space can be manufactured using metal additive manufacturing (AM).

[0027] When the polishing method shown in Figures 1 and 2 is applied, since the polishing body 3 does not need to contact the inner wall surface W1a of the pipe W1, even if the pipe W1 extends on a virtual curve in three-dimensional space, the polishing body 3 can be prevented from getting caught on the inner wall surface W1a of the pipe W1. The polishing body 3 can be moved to most of the area of ​​the inner wall surface W1a of the pipe W1. Furthermore, after the movement, the polishing body 3 can be moved while being in contact with the inner wall surface W1a of the pipe W1, thereby polishing most of the area of ​​the inner wall surface W1a of the pipe W1. Therefore, the polishing method shown in Figures 1 and 2 is particularly suitable for the pipe W1 that extends on a virtual curve in three-dimensional space.

[0028] On the other hand, when a structure having a pipe W1 extending on a virtual curve in a three-dimensional space is manufactured using metal additive manufacturing, meltdown may occur, causing surface roughness on the upper part of the pipe W1. The pipe W2 shown in FIG. 3 is an example of the pipe W1. FIG. 3 is a cross-sectional view showing an example of a pipe to be polished by the polishing method according to the first embodiment. The inner wall surface W2a of the pipe W2 has surface roughness W2b. The surface roughness W2b causes stress concentration and is the cause of failure. When the inner wall surface W2a of the pipe W2 is polished using the polishing method shown in FIGS. 1 and 2, the inner wall surface W2a can be smoothed and the surface roughness W2b can be eliminated.

[0029] (experiment) Next, an experiment in which the inner wall surface of a pipe was polished using an example of the polishing method according to the above-mentioned embodiment 1 will be described with reference to Fig. 4. Fig. 4 is a graph showing the change in arithmetic mean height Sa with respect to the polishing time.

[0030] The inner wall surface of the pipe was polished using an example of the polishing method according to the first embodiment described above. The polishing time T was 0 to 10 min. The arithmetic mean height Sa of the inner wall surface of the pipe according to each example was measured. FIG. 4 also shows pipe W3, which is an example of pipe W1, and polishing body 13, polishing body 13a, polishing body 13b, and polishing body 13c, which are examples of polishing body 3.

[0031] As shown in Fig. 4, as the polishing time T increases, the arithmetic mean height Sa tends to decrease. When polishing is performed, the arithmetic mean height Sa decreases, for example, by 8.9%. Since the arithmetic mean height Sa decreases, it is presumed that the inner wall surface of the pipe W3 has been smoothed and surface roughness has also decreased. Of the polishing body 13, the polishing body 13a, the polishing body 13b, and the polishing body 13c, the polishing body 13c is the most deformed. Since the polishing time T of the polishing body 13c is the longest, it is presumed that the polishing body 13c is the most deformed.

[0032] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. In addition, the present invention can be implemented by appropriately combining the above-described embodiment and examples thereof. [Explanation of symbols]

[0033] 10 Polishing tools 1 First clamping portion 1a Hole 2 Second clamping portion 2a Hole 3, 13, 13a, 13b, 13c Polishing body 3a hole 4, 5 String 4a, 5a one end 4b, 5b other end ST1, ST2 process W1, W2, W3 pipes W1a, W2a inner wall surface W2b rough surface

Claims

[Claim 1] A polishing method for polishing an inner wall surface of a pipe using a polishing tool, comprising the steps of: The polishing tool is A first clamping unit; A second clamping portion; a polishing body disposed between the first clamping portion and the second clamping portion and clamped between the first clamping portion and the second clamping portion; and an approaching means for bringing the first and second clamping portions closer to each other, The polishing body is a spherical body, inserting the abrasive tool into the tube and positioning the abrasive body adjacent to an inner wall surface of the tube; and bringing the first and second clamping parts close to each other to deform the polishing body so that the polishing body comes into contact with the inner wall surface of the tube. Polishing method.

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