Shaft assembly and disassembly structure of industrial machinery

Abstract

A shaft assembly / disassembly structure for industrial machinery includes a mechanical component and a shaft. The mechanical component has a machined surface. The machined surface has a fitting hole for fitting the shaft orthogonal to the machined surface, a plurality of threaded holes spaced apart in the circumferential direction around the fitting hole, and recesses disposed between any of the threaded holes adjacent in the circumferential direction. The shaft has a flange that is in close contact with the machined surface when the shaft is fitted into the fitting hole. The flange has a plurality of through holes through which bolts locking with each threaded hole can pass, and screw holes that can be disposed at positions corresponding to the recesses when the shaft is fitted into the fitting hole. The recesses are formed in areas that do not overlap with the areas around the threaded holes disposed on both sides of the recess in the circumferential direction, and are equal to the outer diameter of the bolt head.

Description

Technical Field

[0001] This application relates to an industrial machine. Prior Technology

[0002] A conventional screw-tapping mechanism for a flange of a shaft member is used in a structure that fits the shaft member into the hole. When the shaft member is pulled out of the hole for maintenance, etc. (see, for example, Patent Document 1), burrs are generated on the machined surface of the pull-out bolt that is pressed into the screw-tapping hole. These burrs affect the reassembly of the shaft member, and the removal of the burrs is also more cumbersome. By providing a release recess on the machined surface of the abutting portion at the front end of the pull-out bolt, the burrs can be prevented from interfering with the tight seal of the machined surface of the flange of the shaft member. [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Invention Patent No. 59-83105 Publication Specification Summary of the Invention

[0004] [The problem the invention aims to solve]

[0005] When a release recess is provided on the machined surface of a flanged shaft component, the contact area between the flange and the machined surface will be reduced, resulting in insufficient friction between them. Therefore, it is desirable to prevent a decrease in assemblability caused by burrs while ensuring sufficient friction between the flange and the machined surface. [Solutions]

[0006] In summary, according to one embodiment, an industrial machine is provided, including a mechanical component and a shaft. The mechanical component has a machined surface. The machined surface has a fitting hole for fitting a shaft orthogonal to the machined surface, a plurality of threaded holes spaced apart in the circumferential direction around the fitting hole, and a recess disposed between any threaded holes adjacent in the circumferential direction. The shaft has a flange that is in close contact with the machined surface when the shaft is fitted into the fitting hole. The flange has a plurality of through holes through which bolts locking with each threaded hole can pass, and a screw-tapping hole that can be disposed at a position corresponding to the recess when the shaft is fitted into the fitting hole. The recess is formed in a region that does not overlap with the region around the threaded holes disposed on both sides of the recess in the circumferential direction, which is equal to the outer diameter of the bolt head. Simple Explanation of the Diagram

[0007] [Figure 1] is a partial cross-sectional schematic diagram of an industrial machine according to an embodiment of this application. [Figure 2] is a three-dimensional schematic diagram of a part of the industrial machine in Figure 1. [Figure 3] is a three-dimensional schematic diagram of the machined surface on the shell of the industrial machinery in Figure 2. [Figure 4] is a partial front view illustrating the recess formed on the machined surface in Figure 2. [Figure 5] is a partial front view of the recess formed on the machined surface in Figure 2 and the fixing bolts that secure the flange. [Figure 6] is a perspective view of the bolt hole formed by the pull-out bolt locking onto the flange in Figure 2. [Figure 7] is a cross-sectional view of the pull-out bolt and the recess in Figure 6. [Figure 8] is a schematic diagram of a deformation example of the concave part in Figure 3. Implementation

[0008] Regarding an embodiment of the industrial machinery 1 of this application, please refer to the drawings and the following description. The industrial machinery 1 of this embodiment is, for example, a robot. As shown in FIG1, the industrial machinery 1 includes a housing (mechanical component) 2 and its rod component 15 rotatably connected to the shaft 3 of the housing 2 about a horizontal axis.

[0009] The housing 2 includes a first plate-shaped portion 4 and a second plate-shaped portion 5 formed as parallel flat plates. With the industrial machinery 1 installed on a horizontal floor or other surface, the first plate-shaped portion 4 and the second plate-shaped portion 5 are arranged along the vertical direction.

[0010] On the outer side of the first plate-shaped portion 4, there is a machined surface A that is a plane along the vertical direction. On the first plate-shaped portion 4, there is a first fitting hole (fitting hole) 6 extending from the machined surface A toward a direction orthogonal to the machined surface A. On the second plate-shaped portion 5, there is a second fitting hole 7 that is coaxially arranged with the first fitting hole 6 and has a smaller inner diameter than the first fitting hole 6.

[0011] The shaft 3 is horizontally inserted into the first fitting hole 6 from the machined surface A side of the first plate-shaped portion 4. The shaft 3 includes a large-diameter portion 8 fitted into the first fitting hole 6, a small-diameter portion 9 fitted into the second fitting hole 7, an intermediate portion 10 disposed between the large-diameter portion 8 and the small-diameter portion 9, and a flange 11 adjacent to the large-diameter portion 8. The intermediate portion 10 is fitted into the inner ring 13 of the bearing 12, while the outer ring 14 of the bearing 12 is fitted into a hole 16 provided at one end of the rod member 15. Thus, the shaft 3 is supported by two support beams between the first plate-shaped portion 4 and the second plate-shaped portion 5, and the rod member 15 is rotatably supported about a horizontal axis serving as the central axis O in the shaft 3.

[0012] As shown in Figure 2, the flange 11 is formed as a disc shape on the flange at one end of the large-diameter portion 8. The flange 11 includes a plurality of through holes 17 evenly spaced in the circumferential direction around the central axis O of the shaft body 3. In addition, the flange 11 has two screw holes 18 spaced 180° apart around the central axis O of the shaft body 3. The screw holes 18 are arranged in the same radial position between the two adjacent through holes 17 in the circumferential direction, with the central axis O of the shaft body 3 as the center.

[0013] On the other hand, as shown in Figure 3, the machined surface A has a plurality of screw holes 19 arranged radially out of the first fitting hole 6 and spaced apart in the circumferential direction. Furthermore, the machined surface A has two recesses 20 positioned vertically above and below the first fitting hole 6, for example, at positions 180° apart around the central axis of the first fitting hole 6 and separated by a horizontal line. Each recess 20 has a bottom surface 21a positioned lower than the machined surface A.

[0014] The radius of the circle connecting the centers of the screw holes 19 on the machined surface A is the same as the radius of the circle connecting the centers of the through holes 17 on the flange 11. Furthermore, the distance from the central axis of the first fitting hole 6 to the recess 20 on the machined surface A is the same as the distance from the central axis O of the shaft 3 to the screw tap hole 18.

[0015] In this embodiment, as shown in FIG4, each recess 20 is circular, and its diameter D is greater than the sum of the outer diameter d of the front end of the pull-out bolt 22 of the screw tap 18 locked to the flange 11 and the radial clearance δ between the through hole 17 and the fixing bolt (bolt) 23. Specifically, it satisfies the following formula. D≧d+2δ Next, as shown in Figure 5, each recess 20 is formed in the area around the screw hole 19 on both sides of the circumference, and does not overlap with the circular area with the outer diameter of the head 24 of the fixing bolt 23 locked in each screw hole 19.

[0016] Please refer to the following description for the effects of the industrial machinery 1 according to an embodiment of this application. According to the industrial machinery 1 of this embodiment, in order to assemble the shaft 3 to the housing 2, with the bearing 12 fitted into the middle portion 10 of the shaft 3, the shaft 3 is inserted horizontally into the first fitting hole 6 from the machined surface A side of the first plate-shaped portion 4. Thus, the small-diameter portion 9, the middle portion 10, and the bearing 12 assembled in the middle portion 10 pass through the first fitting hole 6. Next, the small-diameter portion 9 fits into the second fitting hole 7 of the second plate-shaped portion 5, the outer ring 14 of the bearing 12 fits into the hole 16 of the rod member 15, and the large-diameter portion 8 fits into the first fitting hole 6 of the first plate-shaped portion 4.

[0017] Next, when fitting the large-diameter portion 8 of the shaft 3 into the first fitting hole 6, fitting the small-diameter portion 9 of the shaft 3 into the second fitting hole 7, and sealing the flange 11 to the machined surface A, adjust the assembly position of the shaft 3 around the central axis O. In this way, each through hole 17 of the flange 11 can be positioned opposite to each screw hole 19 of the machined surface A, and the screw tap hole 18 can be positioned opposite to the recess 20.

[0018] Furthermore, with the flange 11 tightly connected to the machined surface A, the fixing bolt 23 passing through the through hole 17 is locked to the screw hole 19 of the machined surface A. In this way, the shaft 3 can be fixed by the two plate-shaped parts 4 and 5 of the housing 2 in a state of being supported by two support beams, and the rod member 15 is rotatably supported about the central axis O of the shaft 3 relative to the housing 2.

[0019] In this situation, since the area of ​​the machined surface A that is closely contacted by the flange 11 is reduced due to the recess 20, no friction will occur between part of the flange 11 and the machined surface A. The area where the flange 11 and the machined surface A are in contact under higher pressure through the fixing bolt 23 locked in the bolt hole 19 of the machined surface A is the area around the bolt hole 19 and the outer diameter 24 of the head of the fixing bolt 23.

[0020] In this embodiment, by forming a recess 20 that does not overlap the area where the flange 11 and the machined surface A are in close contact under high pressure, a significant decrease in the friction between the flange 11 and the machined surface A can be prevented. This prevents the problem of relative movement around the central axis O of the shaft 3 due to insufficient friction between the shaft 3 and the housing 2.

[0021] On the other hand, as shown in Figure 6, when disassembling the shaft 3 from the housing 2, all the fixing bolts 23 are removed, and the pull bolt 22 is tightened into the screw hole 18 of the flange 11. As shown in Figure 7, the bottom surface 21a of the recess 20 is pressed through the front end of the pull bolt 22. In this way, the flange 11 generates a force acting away from the machined surface A, and the shaft 3 can be easily pulled out from the first fitting hole 6 and the second fitting hole 7.

[0022] In this situation, as described above, the pull bolt 22 contacts the bottom surface 21a of the recess 20 and presses it down while rotating, causing the bottom surface 21a of the recess 20 to become rough, resulting in burrs. Since the bottom surface 21a of the recess 20 is positioned lower than the machined surface A, the burrs do not protrude further outward from the machined surface A. Therefore, during the next assembly, it will not obstruct the tight fit between the flange 11 and the machined surface A. Furthermore, it is not necessary to remove the generated burrs, making reassembly easier.

[0023] Furthermore, even if the fixing bolt 23 is aligned correctly with the screw hole 19 on the machined surface A, the flange 11 is offset circumferentially relative to the machined surface A due to the gap between the through hole 17 through which the fixing bolt 23 passes and the fixing bolt 23. Since the recess 20 is circular and its diameter is larger than the sum of the outer diameter of the front end of the pull bolt 22 locked in the screw hole 18 and the radial gap between the through hole 17 and the fixing bolt 23, the front end face of the pull bolt 22 can be positioned within the recess 20 even if the flange 11 is offset circumferentially.

[0024] Thus, even if the flange 11 is configured to be offset in the circumferential direction relative to the housing 2 at the aforementioned gap, the problem of the machined surface A becoming rough can be prevented by locking the front end of the pull bolt 22 to the screw tap 18.

[0025] Furthermore, during the disassembly of the shaft 3, as the pull bolt 22 is gradually tightened into a screw hole 18, an eccentric load will be applied to the flange 11, and the large-diameter portion 8 of the shaft 3 will tilt relative to the first mating hole 6. When this tilt angle increases, wear will occur between the large-diameter portion 8 and the first mating hole 6, making it difficult to pull the shaft 3 out of the first mating hole 6.

[0026] In this embodiment, since the screw tapping hole 18 is arranged on the opposite side of the central shaft O of the shaft body 3, the shaft body 3 can be pulled out from the first fitting hole 6 without wear by alternately locking the two pull bolts 22.

[0027] Specifically, in this embodiment, when the shaft 3 is positioned horizontally, its own weight generates a torque acting around the horizontal axis when it is to be pulled out. In this situation, since the recess 20 is positioned above and below the first fitting hole 6 in the vertical direction, the pull bolt 22 can exert a torque on the shaft 3 in the opposite direction to that around the horizontal axis. Therefore, even if wear occurs due to its own weight, this correction allows the shaft 3 to be easily pulled out.

[0028] In this embodiment, when the shaft 3 is pulled out halfway and the engagement between the small diameter portion 9 and the second fitting hole 7 is released, the rod member 15 or the member in contact with the rod member 15 exerts a load on the top or bottom of the middle portion 10 due to its own weight. Under these circumstances, although a torque about the horizontal axis is generated on the shaft 3, the shaft 3 can be easily pulled out while correcting wear by providing torque in the opposite direction above and below the large diameter portion 8 by the pull bolt 22.

[0029] Furthermore, in this embodiment, although the recess 20 is circular and its diameter is larger than the sum of the outer diameter of the front end of the pull bolt 22 and the radial gap between the through hole 17 and the fixing bolt 23, it is not limited to this. That is, as shown in FIG8, since the front end of the pull bolt 22 can be disposed within the recess 20 even if the flange 11 is configured offset from the radial gap between the through hole 17 and the fixing bolt 23, the recess 20 can also be formed into an ellipse along the circumferential direction. In this case, the radial width relative to the center of the first fitting hole 6 can be larger than the front end diameter of the pull bolt 22. In this way, the reduction in the contact area between the flange 11 and the machined surface A caused by the recess 20 can be reduced, and a larger frictional force can be generated between the flange 11 and the machined surface A.

[0030] Furthermore, although the recess 20 is provided at both the vertically above and vertically below the first fitting hole 6 in this embodiment, it is not limited to this. It can be positioned above and below a horizontal line that is disposed on the machining surface A that passes through the central axis of the first fitting hole 6, or it can be offset vertically above or vertically below.

[0031] Furthermore, within the housing 2, with the flange 11 tightly fitted to the machined surface A, an identification mark can be provided to identify the location of the recess 20. For example, as an identification mark provided on the machined surface A, a mark can be provided on the bottom surface 21a of the recess 20, or, the bottom surface 21a of the recess 20 can be colored only.

[0032] Thus, even with the flange 11 tightly connected to the machined surface A, the identification mark can be checked through the screw tap 18, preventing the pull bolt 22 from being pressed onto the machined surface A outside the recess 20. In addition, the identification mark can also be placed on the radially outer side of the flange 11 that is tightly connected to the machined surface A, and can be a mark such as an arrow indicating the position of the recess 20.

[0033] Furthermore, in this embodiment, although the example shows the rod member 15 rotatably assembled to the housing 2 and shaft 3 as mechanical components, it is not limited to this and can also be applied to any other mechanical component of the industrial machinery 1. Moreover, although the industrial machinery 1 is exemplified as a robot, it can also be any other industrial machinery.

[0034] 1: Industrial Machinery 2: Shell 3: Shaft 4: First plate-shaped part 5: Second plate-shaped part 6: First mating hole 7: Second mating hole 8: Large diameter section 9: Small diameter part 10: Middle section 11: Flange 12: Bearings 13: Inner Circle 14: Outer ring 15: Rod Components 16: Kong 17: Through hole 18: Screw tapping 19: Screw hole 20: concave part 21a: Bottom surface 22: Pull-out bolt 23: Fixing bolts 24: Head A: Machined surface d: outer diameter D: Diameter O: Central axis δ: gap

Claims

1. A shaft assembly / disassembly structure for industrial machinery, comprising: A mechanical component has a machined surface and a shaft. The machined surface includes a fitting hole for the shaft orthogonal to the machined surface, a plurality of threaded holes spaced apart in a circumferential direction around the fitting hole, and a recess disposed between any of the threaded holes adjacent in the circumferential direction. The shaft has a flange that is in close contact with the machined surface when the shaft is fitted into the fitting hole. The flange has a plurality of through holes through which a bolt, which is fastened to each of the threaded holes, passes, and a screw-tapping hole disposed at a position corresponding to the recess when the shaft is fitted into the fitting hole. The recess is formed in a region that does not overlap with the area around the threaded holes on both sides of the recess in the circumferential direction, where the outer diameter of the bolt head is equal to that of the threaded holes. The recess is circular, and its diameter is greater than the sum of the diameter of the front end of the pull bolt fastened to the screw-tapping hole and the radial clearance between the through holes and the bolt.

2. A shaft assembly / disassembly structure for industrial machinery, comprising: A mechanical component has a machined surface and a shaft. The machined surface includes a fitting hole for the shaft orthogonal to the machined surface, a plurality of threaded holes spaced apart in a circumferential direction around the fitting hole, and a recess disposed between any of the threaded holes adjacent in the circumferential direction. The shaft has a flange that is in close contact with the machined surface when the shaft is fitted into the fitting hole. The flange has a plurality of through holes through which a bolt, locked to each of the threaded holes, passes, and a screw-tapping hole disposed at a position corresponding to the recess when the shaft is fitted into the fitting hole. The recess is formed in a region that does not overlap with the area around the threaded holes on both sides of the recess, where the outer diameter of the bolt head is equal to that of the threaded holes. The recess is elliptical, with a length greater than the combined size of the diameter of the front end of the pull bolt locked to the screw-tapping hole and the radial clearance between the through hole and the bolt, and a width slightly greater than the diameter of the front end.

3. The shaft assembly / disassembly structure of industrial machinery as described in claim 1 or 2, wherein, The recesses are respectively located on opposite sides of the central axis separated by the fitting hole.

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