Tightening torque inspection jig

Abstract

To provide a tightening torque inspection jig capable of achieving high efficiency and low cost in a tightening torque inspection process.SOLUTION: An inspection jig 1 according to an embodiment is an inspection jig for inspecting the tightening torque of a clamp section 50. The clamp section 50 has a clamp section 51a, a clamp section 51b facing the clamp section 51a, an elastic section 52 sandwiched between the clamp section 51a and the clamp section 51b, a bolt 53 inserted through the elastic section 52 and the clamp section 51b, and a nut 54 screwed into the bolt 53. The inspection jig 1 includes an extension section 2, an extension section 3 forming a predetermined torque lower limit inspection interval L1 together with the extension section 2, and a connection section 4 connecting the extension section 2 and the extension section 3. The torque lower limit inspection interval L1 is larger than the width W of the clamp section 51b of the clamp section 50 and smaller than the width of the elastic section 52 when the tightening torque of the bolt 53 is the lower limit of the allowable range.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an inspection tool for tightening torque, and more particularly to an inspection tool for inspecting the tightening torque of a clamp portion fixed to the engine of a vehicle such as a truck. [Background technology]

[0002] Around the engines of vehicles such as trucks and buses, pipes through which fluids such as cooling water and oil flow are supported by clamps. More specifically, the pipes are inserted into an elastic material with a through hole, which is sandwiched between two clamp plates (sandwich plates) and fixed by the fastening force of bolts and nuts. If the tightening torque is too small, the pipes may fall off when the engine is running. On the other hand, if the tightening torque is too large, cracks may occur in the pipes, causing the fluid inside to leak out.

[0003] Therefore, after the assembly process of a new engine or a rebuilt engine, the tightening torque of the clamping part is measured by a torque inspection machine to check that it is within the allowable range (proper range). There is a demand for high efficiency and low cost for this tightening torque inspection process.

[0004] Furthermore, when the clamp part to be inspected is placed in a recess in the engine or in a narrow space surrounded by other parts such as pipes, it is difficult to measure the tightening torque using a torque inspection machine, and a solution to this problem is required. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-131925 A Summary of the Invention [Problem to be solved by the invention]

[0006] One of the problems to be solved by the present invention is to provide a tightening torque inspection jig that can improve the efficiency and reduce the cost of the tightening torque inspection process. [Means for solving the problem]

[0007] An inspection tool according to one aspect of the present invention includes: An inspection tool for inspecting the tightening torque of a clamp portion, The clamp portion is A first clamping portion; a second clamping portion opposed to the first clamping portion; an elastic portion sandwiched between the first clamping portion and the second clamping portion; a bolt inserted through the elastic portion and the second clamping portion; A nut that is screwed onto the bolt, The inspection jig is A first extension portion; a second extension portion that, together with the first extension portion, forms a predetermined torque lower limit inspection interval; The lower torque limit inspection interval is greater than the width of the second clamping portion of the clamping portion and smaller than the width of the elastic portion when the tightening torque of the bolt is at the lower limit of the allowable range.

[0008] In addition, in the inspection jig, The first extension portion and the second extension portion may have a distance between inner edges thereof at their tip portions equal to the lower torque limit inspection interval.

[0009] In addition, in the inspection jig, The first extension portion and the second extension portion may be rod members parallel to each other.

[0010] In addition, in the inspection jig, A third extension portion; and and a fourth extension portion forming a predetermined upper torque inspection interval together with the third extension portion, The upper torque limit inspection interval may be greater than the lower torque limit inspection interval and smaller than the width of the elastic portion when the tightening torque of the bolt is at an upper limit of an allowable range.

[0011] In addition, in the inspection jig, The third extension portion may be connected to a tip end of the first extension portion, and the fourth extension portion may be connected to a tip end of the second extension portion.

[0012] In addition, in the inspection jig, The third extension portion and the fourth extension portion may be parallel rod members having a distance between inner edges thereof equal to the upper torque inspection interval.

[0013] In addition, in the inspection jig, Further comprising a connection portion that connects the first extension portion and the second extension portion, The third extension portion may be provided on the opposite side of the first extension portion across the connection portion, and the fourth extension portion may be provided on the opposite side of the second extension portion across the connection portion.

[0014] In addition, in the inspection jig, The third extension portion and the fourth extension portion may have a distance between inner edges at their tip portions that is equal to the upper torque inspection interval.

[0015] In addition, in the inspection jig, The third extension portion and the fourth extension portion may be rod members parallel to each other.

[0016] In addition, in the inspection jig, The gripping portion may include an arc-shaped portion that forms a gripping hole together with the connecting portion.

[0017] An inspection tool according to one aspect of the present invention includes: An inspection tool for inspecting the tightening torque of a clamp portion, The clamp portion is A first clamping portion; a second clamping portion opposed to the first clamping portion; an elastic portion sandwiched between the first clamping portion and the second clamping portion; a bolt inserted through the elastic portion and the second clamping portion; A nut that is screwed onto the bolt, The inspection jig is A first extension portion; a second extension portion that, together with the first extension portion, defines a predetermined upper torque inspection interval; The upper torque inspection interval is smaller than the width of the elastic portion when the tightening torque of the bolt is at the upper limit of the allowable range.

[0018] In addition, in the inspection jig, The first extension portion and the second extension portion may have a distance between inner edges at their tip portions that is equal to the upper torque inspection interval.

[0019] In addition, in the inspection jig, The first extension portion and the second extension portion may be rod members parallel to each other. Effect of the Invention

[0020] According to the present invention, it is possible to provide a tightening torque inspection jig that can improve the efficiency and reduce the cost of the tightening torque inspection process. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a diagram illustrating an inspection tool according to the first embodiment. [Diagram 2] 1A is a diagram showing the clamping part to be inspected, in which (a) is a plan view, (b) is a cross-sectional view taken along line AA in (a), and (c) is a side view. [Diagram 3] 4 is a flowchart for explaining an inspection method using the inspection jig according to the first embodiment. [Figure 4A]FIG. 2 is a diagram for explaining an inspection method according to the first embodiment. [Figure 4B] FIG. 2 is a diagram for explaining an inspection method according to the first embodiment. [Diagram 5] FIG. 11 is a diagram illustrating an inspection tool according to a second embodiment. [Figure 6] 10 is a flowchart for explaining an inspection method using an inspection tool according to a second embodiment. [Figure 7A] FIG. 11 is a diagram for explaining an inspection method according to a second embodiment. [Figure 7B] FIG. 11 is a diagram for explaining an inspection method according to a second embodiment. [Figure 7C] FIG. 11 is a diagram for explaining an inspection method according to a second embodiment. [Figure 7D] FIG. 11 is a diagram for explaining an inspection method according to a second embodiment. [Figure 8] FIG. 13 is a diagram illustrating an inspection tool according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0023] In addition, terms such as "parallel" and "equal" as well as dimensions used in this specification are not limited to their strict meanings, but are interpreted to include a range within which similar functions can be expected.

[0024] (First embodiment) The configuration of an inspection tool 1 according to the first embodiment will be described with reference to FIG.

[0025] The inspection jig 1 is for inspecting the tightening torque of a bolt, and in this embodiment, it is configured as an inspection jig for inspecting the tightening torque of a clamp portion 50 fixed to the engine of a vehicle such as a truck via a mounting bracket 100.

[0026] The inspection jig 1 includes an extension portion 2 (first extension portion), an extension portion 3 (second extension portion) that forms a predetermined torque lower limit inspection interval L1 together with the extension portion 2, a connection portion 4 that connects the extension portion 2 and the extension portion 3, and an arc-shaped portion 5 that forms a gripping hole H together with the connection portion 4. The provision of the gripping hole H makes it easier to handle the inspection jig 1 and facilitates the inspection of the clamp portion in the engine recess. The shape of the arc-shaped portion 5 is not limited to a circular arc. Also, either the connection portion 4 or the arc-shaped portion 5 may be omitted.

[0027] The material of the inspection jig 1 is preferably one that does not wear out with use and has sufficient rigidity, such as a metal such as stainless steel. The inspection jig 1 is manufactured, for example, by subjecting a stainless steel plate to laser processing (laser cutting), press processing, or the like.

[0028] In this embodiment, the extension portion 2 and the extension portion 3 are parallel square bars, as shown in Fig. 1, and the distance between their inner surfaces is equal to the lower torque limit inspection interval L1. Details of the lower torque limit inspection interval L1 will be described after the clamp portion 50 is described.

[0029] The length of extensions 2 and 3 is, for example, 3 to 5 cm, but may be determined according to the placement position of clamp part 50 to be inspected (if placed in a recess, the depth of the recess, etc.).

[0030] The extensions 2 and 3 are not limited to square bars, but may be bar members such as round bars. In this case, the extensions 2 and 3 are configured so that the distance between the inner edges of the extensions 2 and 3 is equal to the lower torque limit inspection interval L1.

[0031] Furthermore, the extensions 2 and 3 may be configured so that the distance between their inner edges at their tip portions (the lower end portions in FIG. 1) is the lower torque limit inspection interval L1. For example, the extensions 2 and 3 may be configured in an inverted eight shape or a curved shape when viewed from the front, and the distance between their tips may be the lower torque limit inspection interval L1.

[0032] Alternatively, the extension portion 2 and the extension portion 3 may be configured such that the distance between their inner edges at the closest portion is the lower torque limit inspection interval L1.

[0033] Here, the configuration of the clamp unit 50 will be described with reference to FIG.

[0034] The clamp portion 50 is fixed to the engine of a vehicle such as a truck via a mounting bracket 100.

[0035] The clamp section 50 includes a clamping section 51a (first clamping section), a clamping section 51b (second clamping section) opposed to the clamping section 51a, an elastic section 52 sandwiched between the clamping sections 51a and 51b, a bolt 53 inserted through the clamping section 51a, the elastic section 52 and the clamping section 51b, and a nut 54 screwed onto the bolt 53. The width of the clamping sections 51a and 51b is, for example, 20 mm.

[0036] In this embodiment, the clipping portions 51a and 51b have curved ends in a side view as shown in Fig. 2(c) . Because of this shape, the elastic portion 52 does not protrude vertically in the fastened state, but protrudes horizontally as shown in Fig. 2(a) .

[0037] The shape of the clamping portions 51a and 51b is not limited to the illustrated shape as long as they are capable of clamping the elastic portion 52. For example, the clamping portions 51a and 51b may be substantially U-shaped in side view or may be simply plate-shaped.

[0038] Also, clamping portion 51a may be integrated with mounting fixture 100. Also, bolt 53 may be provided protruding from the upper surface of clamping portion 51a. In this case, bolt 53 is inserted through elastic portion 52 and clamping portion 51b.

[0039] The elastic part 52 is made of an elastic material such as silicone rubber. In this embodiment, the elastic part 52 is provided with a through hole through which a pipe 110 through which coolant, oil such as lubricant, etc., passes is inserted. As shown in Fig. 2, two pipes 110 are inserted into the elastic part 52. Note that the number of pipes inserted is not limited to two and can be any number.

[0040] Elastic portion 52 is clamped in an elastically deformed state between clamping portion 51a and clamping portion 51b by the fastening force of bolt 53 and nut 54. As the fastening force becomes stronger, elastic portion 52 protrudes more from clamping portion 51b.

[0041] The elastic portion 52 is not limited to being made of one elastic material, but may be made of a combination of multiple elastic materials. For example, the elastic portion 52 may be made by preparing two elastic materials each having a groove formed on its surface, and combining the elastic materials so that the grooves overlap each other.

[0042] The lower torque limit inspection interval L1 of the inspection jig 1 described above is larger than the width W of the pinching portion 51b of the clamp unit 50, and is smaller than the width of the elastic portion 52 when the tightening torque of the bolt 53 is at the lower limit of the allowable range (proper torque range). The allowable range of the tightening torque is, for example, 5 to 10 N·m. The lower torque limit inspection interval L1 is, for example, 21 mm.

[0043] As shown in FIG. 2, the "width" of the clamping portion 51b and the elastic portion 52 is the length of the clamping portion 51b and the elastic portion 52 in the horizontal direction (extension direction of the pipe 110). In this embodiment, the elastic portion 52 is elastically deformed by the tightening torque and protrudes only in the horizontal direction of the clamping portion 51b, so that the torque lower limit inspection interval L1 is determined by the horizontal length of the clamping portion 51b and the elastic portion 52. However, the "width" is not limited to the horizontal length, and may also indicate the vertical length. For example, in the case where the clamping portion 51b is a simple plate-like member and the elastic portion 52 protrudes not only in the horizontal direction but also in the vertical direction of the clamping portion 51b, the torque lower limit inspection interval L1 may be determined by the vertical length of the clamping portion 51b and the elastic portion 52.

[0044] <Inspection method according to the first embodiment> A method for inspecting the tightening torque using the inspection jig 1 will be described with reference to the flow chart of Fig. 3. Each step may be performed by an inspector (person) or an inspection robot.

[0045] Step S11: Bring the inspection jig 1 closer to the clamp portion 50. More specifically, bring the inspection jig 1 closer to the clamp portion 50 so that the clamp portion 50 is sandwiched between the extension portion 2 and the extension portion 3 in the width direction (the direction in which the elastic portion 52 protrudes). For example, an inspector places his / her fingers in the gripping holes H and brings the inspection jig 1 closer to the clamp portion 50 while pointing the tips of the extension portions 2 and 3 toward the clamp portion 50.

[0046] Step S12: Determine whether or not the inspection jig 1 can clamp the elastic portion 52. In more detail, as shown in Fig. 4A, if the extension portion 2 and the extension portion 3 cannot clamp the elastic portion 52 protruding from the clamping portion 51b (S12: Yes), proceed to step S13. On the other hand, as shown in Fig. 4B, if the extension portion 2 and the extension portion 3 can clamp the elastic portion 52 (S12: No), proceed to step S14.

[0047] Step S13: It is determined that the tightening torque of the clamp unit 50 is equal to or greater than the lower limit of the allowable range.

[0048] Step S14: It is determined that the tightening torque of the clamp unit 50 is less than the lower limit of the allowable range.

[0049] As can be seen from the above method, by using the inspection jig 1 according to the first embodiment, it is possible to easily and quickly inspect whether the tightening torque of the clamp portion 50 is equal to or greater than the lower limit of the allowable range.

[0050] Furthermore, since the inspection jig 1 can be manufactured by subjecting a stainless steel plate to laser processing or the like, it can be manufactured more cheaply than a torque inspection machine.

[0051] Therefore, according to the inspection jig of this embodiment, it is possible to improve the efficiency and reduce the cost of the tightening torque inspection process.

[0052] Furthermore, with the inspection jig 1 of this embodiment, it is possible to easily inspect the tightening torque of clamp parts that are located in places that are difficult to inspect with a torque inspection machine, such as recesses or narrow spaces in an engine.

[0053] Second Embodiment An inspection tool 1A according to the second embodiment will be described with reference to Fig. 5. In Fig. 5, components having the same functions as those described in the first embodiment are denoted by the same reference numerals.

[0054] In the first embodiment, only the inspection can be performed as to whether the tightening torque is equal to or greater than the lower limit of the allowable range, but in the second embodiment, the inspection can also be performed as to whether the tightening torque is equal to or less than the upper limit of the allowable range. The second embodiment will be described below, focusing on the differences from the first embodiment.

[0055] In addition to extension portion 2, extension portion 3, connection portion 4 and arc-shaped portion 5, inspection jig 1A also has extension portion 6 (third extension portion) connected to the tip of extension portion 2, and extension portion 7 (fourth extension portion) connected to the tip of extension portion 3.

[0056] The extensions 6 and 7 form a predetermined upper torque inspection interval L2. The upper torque inspection interval L2 is larger than the lower torque inspection interval L1 and is smaller than the width of the elastic portion 52 when the tightening torque of the bolt 53 is at the upper limit of the allowable range. For example, the lower torque inspection interval L1 is 21 mm, and the upper torque inspection interval L2 is 23.5 to 24 mm.

[0057] As described in the first embodiment, the "width" of the elastic portion 52 means the horizontal length of the elastic portion 52 (the extension direction of the pipe 110) in this embodiment, but it may mean the vertical length of the elastic portion 52 depending on the shape of the clamping portion 51b, etc.

[0058] In this embodiment, the extensions 6 and 7 are configured such that the distance between their inner edges at their tips (the lower ends in Fig. 5) is the upper torque inspection interval L2. As shown in Fig. 5, the extensions 6 and 7 are parallel square bars, and the distance between their inner faces is equal to the upper torque inspection interval L2.

[0059] The extensions 6 and 7 are not limited to square bars, but may be bar members such as round bars. In this case, the extensions 6 and 7 are configured so that the distance between the inner edges of the extensions 6 and 7 is equal to the upper torque inspection interval L2.

[0060] <Inspection method according to the second embodiment> A method for inspecting the tightening torque using the inspection jig 1A will be described with reference to the flow chart of Fig. 6. Each step may be performed by an inspector (person) or an inspection robot.

[0061] Step S21: Bring the inspection jig 1A closer to the clamp unit 50. More specifically, bring the inspection jig 1A closer to the clamp unit 50 so that the clamp unit 50 is sandwiched widthwise between the extension units 6 and 7. For example, an inspector places his / her fingers in the gripping holes H and brings the inspection jig 1A closer to the clamp unit 50 while pointing the tips of the extension units 6 and 7 toward the clamp unit 50.

[0062] Step S22: Determine whether the inspection jig 1A can clamp the elastic portion 52. In more detail, as shown in Fig. 7A, if the extension portion 6 and the extension portion 7 can clamp the elastic portion 52 protruding from the clamping portion 51b (S22: Yes), proceed to step S23. On the other hand, as shown in Fig. 7B, if the extension portion 6 and the extension portion 7 cannot clamp the elastic portion 52 (S22: No), proceed to step S24.

[0063] Step S23: It is determined that the tightening torque of the clamp unit 50 is equal to or less than the upper limit of the allowable range.

[0064] Step S24: It is determined that the tightening torque of the clamp unit 50 exceeds the upper limit of the allowable range.

[0065] Step S25: The inspection jig 1A is brought even closer to the clamp unit 50. More specifically, the inspection jig 1A is brought closer to the clamp unit 50 so that the extension portion 2 and the extension portion 3 sandwich the clamp unit 50 in the width direction.

[0066] Step S26: Determine whether or not the inspection jig 1A is unable to clamp the elastic portion 52. In particular, as shown in Fig. 7C, if the extension portion 2 and the extension portion 3 are unable to clamp the elastic portion 52 protruding from the clamping portion 51b (S26: Yes), proceed to step S27. Conversely, as shown in Fig. 7D, if the extension portion 2 and the extension portion 3 are able to clamp the elastic portion 52 (S26: No), proceed to step S28.

[0067] Step S27: It is determined that the tightening torque of the clamp unit 50 is equal to or greater than the lower limit of the allowable range (that is, the tightening torque is within the allowable range).

[0068] Step S28: It is determined that the tightening torque of the clamp unit 50 is less than the lower limit of the allowable range.

[0069] As can be seen from the above method, by using the inspection jig 1A of the second embodiment, it is possible to easily inspect not only whether the tightening torque of the clamp portion 50 is equal to or greater than the lower limit of the allowable range, but also whether the tightening torque is equal to or less than the upper limit of the allowable range.

[0070] (Third embodiment) The configuration of an inspection jig 1B according to the third embodiment will be described with reference to Fig. 8. The third embodiment differs from the second embodiment in that the extension portion 6 and the extension portion 7 are provided on the opposite side of the connection portion 4 from the extension portion 2 and the extension portion 3. The third embodiment will be described below, focusing on the differences.

[0071] Similar to the second embodiment, the inspection jig 1B includes an extension portion 2, an extension portion 3, a connection portion 4, an extension portion 6, and an extension portion 7. A difference is that in this embodiment, the extension portion 6 is not connected to the tip of the extension portion 2, but is provided on the opposite side of the extension portion 2 with the connection portion 4 in between. Similarly, the extension portion 7 is not connected to the tip of the extension portion 3, but is provided on the opposite side of the extension portion 3 with the connection portion 4 in between.

[0072] As in the second embodiment, the extensions 2 and 3 form a lower torque limit inspection interval L1, and the extensions 6 and 7 form an upper torque inspection interval L2.

[0073] The inspection method using the inspection jig 1B is almost the same as the inspection method described in the second embodiment. However, whereas in the second embodiment, the inspection jig 1A is brought even closer to the clamp unit 50 in step S25, in this embodiment, the inspection jig 1B is once moved away from the clamp unit 50, the inspection jig 1B is inverted so that the tips of the extension portion 2 and the extension portion 3 face the clamp unit 50, and then the inspection jig 1B is brought closer to the clamp unit 50.

[0074] In this embodiment, it is also possible to first bring extension portion 2 and extension portion 3 closer to clamp portion 50 and perform the judgments of steps S26 to S28, and then bring extension portion 6 and extension portion 7 closer to clamp portion 50 and perform the judgments of steps S22 to S24.

[0075] According to the inspection jig 1B of the third embodiment, the height of the mounting bracket 100 is low, and therefore it is possible to avoid a situation in which, with the inspection jig 1A, the extensions 6 and 7 come into contact with the engine surface, making it impossible to perform inspection using the extensions 2 and 3.

[0076] Based on the above description, a person skilled in the art may be able to conceive additional effects and various modifications of the present invention, but the aspects of the present invention are not limited to the above-mentioned embodiments. Various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and intent of the present invention derived from the contents defined in the claims and their equivalents.

[0077] For example, in the case of an application for inspecting only whether or not the tightening torque exceeds the upper limit of the allowable range, the extensions 2 and 3 may be omitted from the inspection jig according to the third embodiment.

[0078] In the above embodiment of the inspection jig, the extensions 2 and 3 are formed of rod-shaped members, but this is not limited as long as the lower torque limit inspection interval can be formed. For example, a recess having an opening width equal to the lower torque limit inspection interval L1 may be formed on the surface of a rectangular metal block. In this case, the inner wall of the recess constitutes the extensions 2 and 3. Furthermore, another recess having an opening width equal to the upper torque inspection interval L2 may be formed on the bottom surface of the recess. In this case, the inner wall of the other recess constitutes the extensions 6 and 7.

[0079] In the above embodiment, the clamp portion fixed to the engine of the vehicle is the subject of inspection, but the clamp portion to be inspected is not limited to this. [Explanation of symbols]

[0080] 1,1A Inspection fixture 2,3,6,7 extension 4 Connection 5 Arc part 50 Clamp section 51a, 51b Clamping part 52 Elastic part 53 Volts 54 Nut 100 Mounting bracket 110 Pipe H gripping hole

Claims

1. An inspection tool for inspecting the tightening torque of a clamp portion, The clamp portion is A first clamping portion; a second clamping portion opposed to the first clamping portion; an elastic portion sandwiched between the first clamping portion and the second clamping portion; a bolt inserted through the elastic portion and the second clamping portion; A nut that is screwed onto the bolt, The inspection jig is A first extension portion; a second extension portion that, together with the first extension portion, defines a predetermined torque lower limit inspection interval; An inspection jig, wherein the lower torque limit inspection interval is greater than the width of the second clamping portion of the clamping portion and smaller than the width of the elastic portion when the tightening torque of the bolt is at the lower limit of the allowable range.

2. The inspection jig according to claim 1 , wherein the distance between inner edges of the first extension portion and the second extension portion at their tips is equal to the lower torque limit inspection interval.

3. The inspection jig according to claim 2 , wherein the first extension portion and the second extension portion are rod members parallel to each other.

4. A third extension portion; and and a fourth extension portion forming a predetermined upper torque inspection interval together with the third extension portion, 2. The inspection tool according to claim 1, wherein the upper torque inspection interval is greater than the lower torque inspection interval and is smaller than a width of the elastic portion when the tightening torque of the bolt is at an upper limit of an allowable range.

5. The inspection tool according to claim 4 , wherein the third extension portion is connected to a tip end of the first extension portion, and the fourth extension portion is connected to a tip end of the second extension portion.

6. 6. The inspection jig according to claim 5, wherein the third extension portion and the fourth extension portion are parallel rod members having a distance between inner edges thereof equal to the upper torque inspection interval.

7. A connection portion that connects the first extension portion and the second extension portion is further provided, 5. The inspection jig according to claim 4, wherein the third extension portion is provided on the opposite side of the first extension portion across the connection portion, and the fourth extension portion is provided on the opposite side of the second extension portion across the connection portion.

8. The inspection tool according to claim 7 , wherein the third extension portion and the fourth extension portion have a distance between inner edges at their tips that is equal to the upper torque inspection interval.

9. The inspection jig according to claim 8 , wherein the third extension portion and the fourth extension portion are rod members parallel to each other.

10. a connection portion that connects the first extension portion and the second extension portion; The inspection tool according to any one of claims 1 to 9, further comprising an arc-shaped portion which, together with the connection portion, forms a gripping hole.

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