JP2019076823A - Connection structure - Google Patents

Abstract

To further enhance durability of a bolt part.SOLUTION: A connection structure 100, which connects an agitating shaft 40 to a driving shaft 52a of a driving part, comprises: a first coupling 111 that rotates together with the driving shaft; a second coupling 112, fastened to the first coupling, which has a shaft hole 112a through which the agitating shaft is inserted; and a detachment preventing member 114, in which a penetration hole 114a through which a bolt part 40g provided on an end surface 40d of a base end part 40b of the agitating shaft penetrates is formed and whose peripheral edge part 114c is locked to an outer edge part 112a1 of the shaft hole, which is configured so that the base end part is pressed against the shaft hole when a nut 116 is tightly fastened to the bolt part penetrating through the penetration hole so as to restrict the agitating shaft from moving in a detachment direction, where at least three bolt parts are provided on the end surface of the base end part so as to bypass a center Oof the end surface, and the bolt parts are arranged at the same distances away from the center and adjacent bolt parts are arranged at equal intervals respectively.SELECTED DRAWING: Figure 2

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a connecting structure for connecting a stirring shaft on which a stirring blade of a stirrer is mounted and a driving shaft of a drive unit.

  In general, a reaction vessel that carries out a chemical reaction such as dissolution of solid matter and formation of solid matter is provided with a stirrer for accelerating the reaction and preventing sedimentation of solid matter. The agitator transmits rotational power obtained from the motor serving as a drive source with a transmission mechanism such as a V-belt, and is decelerated to a desired number of revolutions by the reduction gear, and the rotational power decelerated by the reduction gear After being transmitted to the drive shaft, the stirring blade is rotated via the stirring shaft connected to the drive shaft to thereby stir the liquid in the reaction tank.

The drive shaft and the stirring shaft are usually separate parts for the use of commercially available products, the addition of bearings and sealing functions, and replacement at the time of wear, via a coupling structure composed of a coupling etc. It is connected. However, by continuously using the stirrer, which is a large-sized device having a predetermined size, for a long time, the bolt connecting the connection structure is loosened or broken and the stirring shaft falls into the tank. there were. For example, if it is a tank of about 30 m ³ used for chlorine leaching of nickel sulfide compounds, the dropping of the stirring shaft does not occur even with a conventional stirrer (diameter of about 160 mm of the stirring shaft). With a tank of approximately 60 m ³ , with the conventional stirrer (approximately 210 mm in diameter of the stirring shaft) enlarged to match the size of the tank, the stirring shaft may be dropped, which causes a major problem in operation It was

  Thus, as a prior art for preventing the stirring shaft of the enlarged stirrer from falling off from the driving shaft, Patent Document 1 discloses a second coupling to which the stirring shaft is attached, and a driving shaft of the driving unit. A coupling device is disclosed that rigidly fastens with a first coupling that rotates integrally therewith. The coupling device is configured to be able to firmly fasten both couplings with members such as a fall-off preventing member, a washer, a bolt, and a nut, so that the nut tightened to the bolt portion of the stirring shaft is loosened and the stirring shaft is It prevents the bolt from coming off.

JP, 2011-200775, A

  However, a load is applied to the bolt that joins the stirring shaft and the flange coupling due to the rotational runout of the stirring shaft due to the attachment of the stirring blade, and fatigue due to repeated use. The stirring shaft may fall off due to breakage or loosening. For example, when the contact between the base end of the stirring shaft that joins the stirring shaft and the flange coupling and the shaft hole worsens due to a construction failure or temperature change, a load is applied to the bolt portion formed in the base end. If the bolt is left as it is, the bolt may break. That is, it is desirable to enhance the durability with which breakage of the bolt portion is less likely to occur even with aged deterioration, construction failure, temperature change and the like.

  The present invention has been made in view of the above problems, and provides a new and improved connection structure capable of preventing the dropout of the stirring shaft by further enhancing the durability of the bolt portion. With the goal.

  One aspect of the present invention is a connecting structure for connecting a stirring shaft to which a stirring blade of a stirrer is attached and a driving shaft of a drive unit, the first coupling rotating integrally with the driving shaft A second coupling which is fastened to the first coupling and has an axial hole through which the stirring shaft is inserted, and a through hole through which a bolt portion provided on an end face of the proximal end of the stirring shaft passes When the nut is formed, the peripheral edge portion is engaged with the outer edge portion of the shaft hole on the top surface side of the second coupling, and a nut is tightened to the bolt portion penetrating the through hole; The base end portion is pressed to prevent movement of the stirring shaft in the falling direction, and the bolt portion is provided on the end surface of the base end portion of the stirring shaft. At least three bolts are provided to bypass the center of the end face, and each bolt The present invention is characterized in that adjacent bolt portions are provided at equal intervals at the same distance from the center, and three or more of the through holes are provided at positions facing the bolt portions in the fall-off preventing member. I assume.

  According to one aspect of the present invention, at least three or more bolt portions are provided at equal intervals so as to bypass, particularly at the end face of the proximal end portion of the stirring shaft, a central portion with a large load during operation of the stirrer. By dispersing the load on the bolt portion and reducing the risk of breakage of the bolt portion, it is possible to prevent the falling off of the stirring shaft.

  At this time, in one aspect of the present invention, the bolt portion is provided at a position closer to the outer edge of the end surface than the center of the end surface of the base end portion, and the through hole is closer to the center of the drop prevention member Also, it may be provided at a position close to the outer edge of the fall-off preventing member.

  According to this configuration, the end face of the proximal end portion of the stirring shaft is configured to bypass the particularly heavy load center during operation, and the durability of the bolt portion can be further enhanced.

  Further, in one aspect of the present invention, the nut to be tightened to the bolt portion may be provided such that the outer edge thereof is on the inner side than the peripheral edge portion of the fall-off preventing member.

  In this way, the nut for tightening the bolt portion is accommodated in the fall-off preventing member, so that the durability of the connection portion between the bolt portion and the nut can be surely improved in the limited space in the second coupling. Become.

  Further, in one aspect of the present invention, each bolt portion is configured such that a ratio of a sum of cross-sectional areas of the bolt portions to a cross-sectional area of the stirring shaft is 0.1 or more. Adjacent bolt portions may be provided at equal intervals at the same distance from the center.

  In this way, the durability of the bolt portion can be enhanced more reliably than in the conventional case where there is only one bolt portion, so that the stirring shaft can be reliably prevented from falling off.

  As described above, according to the present invention, three or more bolt portions are separated by the same distance from the center so as to detour around the center of a large load during operation particularly at the end face of the proximal end of the stirring shaft. By providing the fitting bolt portions at equal intervals, the load on the bolt portion is dispersed and reduced, so that it is possible to prevent the stirring shaft from falling off due to breakage of the bolt portion or the like.

It is a perspective view showing a schematic structure of a stirrer to which a connection structure concerning one embodiment of the present invention is applied. It is a fragmentary sectional view showing a schematic structure of a connection structure concerning one embodiment of the present invention. It is a perspective view which shows the structure of the principal part of the connection structure which concerns on one Embodiment of this invention. It is a perspective view which shows the structure of the principal part of the connection structure body which becomes a prior art example. (A) is operation | movement explanatory drawing which shows the test method of stress analysis of the bolt part of the connection structure used as a conventional example, (B) is a test result of stress analysis of the bolt part of the connection used as a conventional example. Is an explanatory view showing a safety factor. (A) is operation | movement explanatory drawing which shows the test method of the stress analysis of the bolt part of the connection structure which concerns on one Embodiment of this invention, (B) is a connection structure which concerns on one Embodiment of this invention It is explanatory drawing which shows the test result of the stress analysis of a bolt part by a safety factor.

  Hereinafter, preferred embodiments of the present invention will be described in detail. Note that the present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all of the configurations described in the present embodiment are essential as means for solving the present invention. Not necessarily.

  First, a schematic configuration of a stirrer to which a connecting structure according to an embodiment of the present invention is applied will be described using the drawings. FIG. 1 is a perspective view showing a schematic configuration of a stirrer to which a connecting structure according to an embodiment of the present invention is applied.

  The stirrer 10 is provided in a reaction tank or the like that performs a chemical reaction such as dissolution of a solid, formation of a solid, etc., and is used when stirring a solution, a slurry liquid, etc. contained inside the tank 30. . As shown in FIG. 1, the stirrer 10 has a stirring shaft 40 provided with a stirring blade 41 for stirring a liquid or the like contained in the tank 30, a drive unit 50 for rotationally driving the stirring shaft 40, and stirring. The connecting structure 100 connecting the shaft 40 and the drive unit 50 is provided.

  The tank 30 contains a liquid or the like inside, and as shown in FIG. 1, a tank main body 31 formed in a bottomed cylindrical shape with an open upper end, and a lid 32 that closes the opening of the tank main body 31. And.

  The tank body 31 accommodates a solution, a slurry liquid, and the like inside. The stirring shaft 40 is accommodated in the tank body 31 so that the base end 40 b of the stirring shaft 40 is pulled out from the through hole 33 formed on the top surface of the lid 32.

  The lid 32 is provided so as to be removable from the tank body 31. In the tank 30, replacement of the stirring shaft 40 is performed with the lid 32 removed from the tank body 31. Further, the lid portion 32 is formed with a through hole 33 for exposing the base end portion 40 b of the stirring shaft 40 connected to the connection structure 100 to the outside of the tank body portion 31. Furthermore, a protection member 34 is provided on the main surface 32 a of the lid 32 to protect the connection structure 100, the speed reduction mechanism 52 described later, and the proximal end 40 b of the stirring shaft 40 drawn from the through hole 33. The protective member 34 has, for example, a divided structure which is provided in a cylindrical shape, a conical shape, and is divided into a plurality of pieces.

  As shown in FIG. 1, when the stirring shaft 40 is inserted into the tank 30 with the distal end 40 a as an insertion end and accommodated in the tank 30, the proximal end 40 b is pulled out from the lid 32 to the outside. Such a stirring shaft 40 is provided with a stirring blade 41 for stirring the liquid stored in the tank 30 from the tip 40 a to the middle.

  As shown in FIG. 1, the stirring blade 41 is integrally provided by welding or the like at the tip portion 40 a and the middle portion of the stirring shaft 40. Specifically, when the stirring shaft 40 is accommodated in the inside of the tank 30, the stirring blade 41 is provided in the vicinity of the bottom of the tank 30 and in the middle in the height direction of the tank 30. The stirring blade 41 is rotationally driven integrally with the stirring shaft 40 as the stirring shaft 40 is rotationally driven, and stirs the liquid contained in the tank 30.

  In addition, although each stirring blade 41 illustrates the thing which has a blade | wing of 2 sheets in FIG. 1, it may have a blade | wing of other several sheets, such as three sheets and four sheets. Moreover, the stirring blade 41 is not limited to being provided in two places of the stirring shaft 40, What is necessary is just to be provided in at least one place. Furthermore, the stirring blade 41 is not limited to the long plate shape shown in FIG. 1 and may have a spiral blade.

  The driving unit 50, as shown in FIG. 1, includes a motor 51 for rotationally driving the stirring shaft 40, and a reduction mechanism 52 for adjusting the number of rotations of the stirring shaft 40 with respect to the number of rotations of the rotation shaft 51a of the motor 51. Have. The motor 51 is fixed to a fixing member (not shown) and installed above the tank 30. The reduction mechanism 52 is formed by combining a plurality of gears, and adjusts the number of rotations of the drive shaft 52 a connected to the stirring shaft 40 to the number of rotations of the rotation shaft 51 a of the motor 51.

  Such a drive unit 50 transmits the rotational driving force of the motor 51 to the stirring shaft 40 via the reduction mechanism 52 to rotationally drive the stirring shaft 40. The stirring shaft 40 to which the stirring blade 41 of the stirrer 10 is attached and the driving shaft 52 a of the driving unit 50 are connected via the connecting structure 100.

  Next, the configuration of the connection structure according to an embodiment of the present invention will be described using the drawings. FIG. 2 is a partial cross-sectional view showing a schematic configuration of a connection structure according to an embodiment of the present invention, and FIG. 3 is a perspective view showing the configuration of main parts of the connection structure according to an embodiment of the present invention. It is. 2 is a cross-sectional view in which only the first coupling and the second coupling of the connection structure are cut in the vertical direction, and FIG. 3 is a state in which the first coupling of the connection structure is removed. FIG.

  The connection structure 100 according to the embodiment of the present invention includes a first coupling 111, a second coupling 112, a key member 113, and an anti-falling member 114, as shown in FIG. .

  As shown in FIG. 2, the first coupling 111 has a cylindrical main body portion 111b having a shaft hole 111a through which the drive shaft 52a of the reduction gear mechanism 52 is inserted, and a flange portion 111c is formed on the main body portion 111b. Are integrally formed. The drive shaft 52a is inserted into the shaft hole 111a, and the main body portion 111b is integrated with the inserted drive shaft 52a by screwing with welding or a bolt or the like. Thus, the first coupling 111 is rotationally driven integrally with the drive shaft 52a. Further, a plurality of first insertion holes 111 d penetrating in the thickness direction are formed in the flange portion 111 c.

  The second coupling 112 is tightened with the first coupling 111, and as shown in FIG. 2, has a shaft hole 112a in which a taper corresponding to the tapered portion 40c of the stirring shaft 40 is formed on the inner peripheral surface side. It has a cylindrical main body 112b, and a flange 112d is integrally formed on the main body 112b.

  A second longitudinal groove (not shown) is formed on the inner surface of the shaft hole 112a of the main body 112b, into which the key member 113 for transmitting the rotational drive force from the drive unit 50 to the stirring shaft 40 substantially parallel to the axis P is inserted. It is done. The second vertical groove and the first vertical groove 40e constitute a key groove into which the key member 113 for transmitting the rotational driving force from the drive unit 50 to the stirring shaft 40 is inserted.

  Further, as shown in FIGS. 2 and 3, the flange portion 112 d is formed with a plurality of second insertion holes 112 f penetrating in the thickness direction. The second insertion holes 112 f are respectively formed corresponding to the first insertion holes 111 d of the first coupling 111. For this reason, the first coupling 111 and the second coupling 112 are provided by bringing the flanges 111c and 112d into abutment with the first insertion hole 111d and the second insertion hole 112f in alignment.

  Then, in the first coupling 111 and the second coupling 112, the bolt 117a is inserted from the second coupling 112 side into the second insertion hole 112f and the first insertion hole 111d, and the first coupling 111 It is fixed by being tightened by a nut 117 b on the side 111. Accordingly, when the drive shaft 52a rotates, the second coupling 112 is rotationally driven integrally with the first coupling 111 integrated with the drive shaft 52a.

  As shown in FIG. 2, a tapered portion 40c whose diameter gradually decreases toward the proximal end 40b is provided at the proximal end 40b of the stirring shaft 40 inserted into the axial hole 112a of the second coupling 112. ing. In the tapered portion 40c, a first longitudinal groove 40e is formed substantially in parallel with the axis P of the stirring shaft 40 from the base end surface 40d on the base end 40b side to the tip end 40a side to a predetermined position.

  The first longitudinal groove 40e is formed such that the groove bottom is substantially parallel to the axis P of the stirring shaft 40, and the key member 13 for transmitting the rotational driving force from the drive unit 50 to the stirring shaft 40 is attached It is done. Further, screw holes 40f are formed in the first vertical grooves 40e in the direction orthogonal to the axis P. A bolt 118 for fixing the key member 13 is screwed to the screw hole 40f.

  Further, on the end face 40d on the base end 40b side of the stirring shaft 40, there is provided a bolt 40g having a screw groove formed on the outer periphery so as to protrude in the direction from the tip 40a to the base end 40b. There is. As shown in FIG. 2, the bolt portion 40 g penetrates the detachment preventing member 114 in which the through hole 40 a is formed, and the nut 116 is tightened to a portion penetrating the detachment preventing member 114, whereby the stirring shaft 40 is formed. Is supported by the fall prevention member 114.

In this embodiment, as shown in FIGS. 2 and 3, three bolt portions 40 g are provided on the end surface 40 d of the proximal end 40 b of the stirring shaft 40 at the center O of the end surface 40 d of the proximal end 40 b of the stirring shaft 40. at a same distance from _a, characterized in that the center O _a bolt portion 40g adjacent to bypass the are provided at equal intervals, respectively. Further, the bolt portion 40g, as shown in FIGS. 2 and 3, the center _{O A} of the end face 40d of the base end portion 40b of the stirring shaft 40 provided on the outer edge near the position of the end face 40d, the through-hole 114a is It is provided at a position closer to the peripheral portion 114c of the stopper member 114 from the center _{O B} of the stopper member 114.

In the present embodiment, three bolt portions 40g are provided on the end face 40d of the base end portion 40b, but the number of bolt portions 40g is equal to the load on each bolt portion 40g while the stirring shaft 40 is rotationally driven. In order to take the effect, it is sufficient if at least three or more. That is, if the bolt portion 40g is provided so that the center O _A of the end face 40d of the center and the base end portion 40b of the regular polygon made from the center of each bolt portion 40g coincide, the number of bolt portion 40g Is not limited to three. For this reason, the number of bolt portions 40g is not limited to three, and may be four or more within the allowable range of the end face 40d of the base end portion 40b of the stirring shaft 40 on which the bolt portions 40 are installed. .

Thus, in the present embodiment, at a same distance from the larger center O _A of the load during the operation of the particular stirrer 10 at the end face 40d of the base end portion 40b of the stirring shaft 40, bypassing the portion of the center O _A As described above, the load on the bolt portion 40g is dispersed by providing three bolt portions 40g at equal intervals. Therefore, the durability of the bolt portion 40g is enhanced, and the drop of the stirring shaft 40 can be prevented by reducing the risk of breakage or the like of the bolt portion 40g.

In the present embodiment, in order to further enhance the durability of the bolt portion 40g particularly bypassing the large center O _A of the load during operation in the end surface 40d of the base end portion 40b of the stirring shaft 40, the bolt portion 40g is It is preferable to be provided at a position close to the outer edge of the end face 40d. However, in order to improve the durability of the connection between the bolt portion 40g and the nut 116 within the limited space in the second coupling 112, the outer edge of the nut 116 for tightening the bolt portion 40g is the fall prevention member 114. It is provided inside the outer edge.

  The key member 113 transmits the rotational driving force transmitted to the second coupling 112 to the stirring shaft 40. As shown in FIG. 2, the key member 113 has a rectangular plate shape, and when attached to the first longitudinal groove 40 e formed in the proximal end 40 b of the stirring shaft 40, the one end 113 a is the stirring shaft 40. And a length projecting from the end face 40d to the base end 40b.

  Further, in the key member 113, an insertion hole 113b penetrating in the thickness direction is provided at a position corresponding to the screw hole 40f formed in the first vertical groove 40e when attached to the first vertical groove 40e. It is formed. The insertion hole 113 b is formed continuously with an insertion portion through which the shaft portion of the bolt 118 is inserted and a concave portion in which the head of the bolt 118 is hidden. The key member 113 is fixed to the first longitudinal groove 40e by inserting the bolt 118 into the insertion hole 113b and screwing it to the screw hole 40f.

  Thus, in the present embodiment, the key member 113 is formed on the first longitudinal groove 40 e formed on the tapered surface 40 c of the proximal end 40 b of the stirring shaft 40 and on the inner surface of the axial hole 112 a of the second coupling 112. It intervenes between the formed 2nd vertical groove (not shown), and is provided. Therefore, the rotational drive from the drive shaft 52 a is transmitted from the first coupling 111 to the second coupling 112, and the rotational drive transmitted to the second coupling 112 is the stirring shaft via the key member 113. It is transmitted to 40 to be rotationally driven.

  As shown in FIGS. 2 and 3, the anti-falling member 114 is provided in a substantially disc shape, and the outer edge portion 112 a 1 of the shaft hole 112 a on the top surface side of the second coupling 112, that is, the first It has an outer diameter larger than the outer diameter of the outer edge portion 112a1 of the axial hole 112a on the side facing the coupling 111, and has a thickness with mechanical strength capable of supporting the stirring shaft 40. Therefore, the peripheral edge portion 114 c of the fall-off preventing member 114 is locked to the outer edge portion 112 a 1 of the axial hole 112 a on the top surface side of the second coupling 112.

In the present embodiment, as shown in FIG. 2, the position of the through holes 114 a passing through in the thickness direction is opposed to each of the bolt portions 40 g in order to allow the three bolt portions 40 g to be inserted. Three are formed. Specifically, the through holes 114a so as to respectively face the bolt portion 40 g, it is provided at a position closer to the peripheral portion 114c of the center _O stopper members 114 than _B of the stopper member 114.

  The through hole 114a has a diameter slightly larger than the bolt portion 40g of the stirring shaft 40, and the bolt portion 40g is inserted. The fall preventing member 114 is disposed on the end face 40 d of the proximal end 40 b of the stirring shaft 40 by inserting the bolt portion 40 g into the through hole 114 a. In this manner, the fall-off preventing member 114 is fixed to the end face 40 d on the proximal end 40 b side of the stirring shaft 40 by tightening the nut 116 to the bolt 40 g.

  Further, the dropout prevention member 114 is formed with a notch 114b which is cut out so as to penetrate in the thickness direction. The notch 114 b is engaged with the one end 113 a of the key member 113 protruding from the proximal end 40 b of the stirring shaft 40 when the drop prevention member 114 is disposed on the end face 40 d of the stirring shaft 40. For this reason, the falling-off preventing member 114 reliably rotates and drives integrally with the stirring shaft 40.

  That is, after the stirring shaft 40 is inserted into the axial hole 112a of the second coupling 112, the through-hole 114a is inserted into the bolt portion 40g of the stirring shaft 40, and the falling prevention member 114 is inserted into the notch 114b. 40 is disposed on the base end surface 40d of the stirring shaft 40 so as to be engaged with the one end portion 113a of the key member 113 projecting from the base end surface 40d of 40 and fixed on the base end surface 40d of the stirring shaft 40 by the nut 116 There is.

  Such a fall-off preventing member 114 abuts against the abutting surface 112 h around the shaft hole 112 a of the second coupling 112, and restricts the movement of the stirring shaft 40 in the dropping direction on the tip portion 40 a side, The stirring shaft 40 is prevented from falling off the second coupling 112. That is, when the nut 116 is tightened on the bolt portion 40g penetrating the through hole 114a, the proximal end portion 40b of the stirring shaft 40 is pressed toward the shaft hole 112a, and the falling out direction of the stirring shaft 40 It is possible to regulate the movement of

As described above, in this embodiment, as in particular to bypass the large center O _A of the load during operation of the agitator 10 at the end face 40d of the base end portion 40b of the stirring shaft 40, at least three or more bolts The parts 40g are provided such that adjacent bolt parts 40g are equally spaced. As a result, the load on the bolt portion 40g provided at the base end 40b of the stirring shaft 40 is increased particularly with the enlargement of the stirrer 10, and troubles such as breakage or loosening of the bolt portion 40g occur. Even if it becomes easier, the load on the bolt portion 40g is dispersed to improve the durability of the bolt portion 40g. For this reason, in the agitator 10 to which the connecting structure 100 according to an embodiment of the present invention is applied, the frequency and risk of falling of the agitation shaft 40 are reduced, and the response to unexpected troubles is reduced. It has a very large industrial value because it leads to the stable operation of

  Next, a connecting structure according to an embodiment of the present invention will be described in detail by way of examples. The present invention is not limited to these examples.

  FIG. 4 is a perspective view showing the configuration of the main part of a conventional connecting structure, and FIG. 5 (A) is an operation explanation showing a test method of stress analysis of a bolt portion of the conventional connecting structure. It is a figure and Drawing 5 (B) is an explanatory view showing a test result of stress analysis of a bolt part of a connection example which becomes a conventional example by a safety factor. FIG. 6A is an operation explanatory view showing a test method of stress analysis of a bolt portion of a connection structure according to an embodiment of the present invention, and FIG. 6B is an embodiment of the present invention It is explanatory drawing which shows the test result of the stress analysis of the bolt part of the connection structure which concerns on 2 by a safety factor. In addition, FIG. 4 is a perspective view which shows the state which removed the 1st coupling of a connection structure. In addition, software for SOLIDWORKS (Solid Works Japan Co., Ltd.) is used to simulate stress analysis of the bolt portion of the connected structure in the conventional example and the embodiment, and the connected structure used in the simulation is made of titanium. The material was used.

  In the connection structure according to the conventional example, as shown in FIG. 4, the bolt portion 4g having an outer diameter of 64 mm is 1 on the proximal end side of the stirring shaft 4 with respect to the end face of the proximal end portion having an outer diameter of 184 mm. The nut 16 is tightened to the bolt 4g. That is, the ratio of the cross-sectional area of the bolt 4 g to the cross-sectional area of the stirring shaft 4 is 0.121.

  Further, the second coupling 12 having an axial hole (not shown) which is fastened to the first coupling (not shown) and into which the stirring shaft 4 is inserted is a connecting structure 100 according to an embodiment of the present invention (FIG. 2 and FIG. 3), as shown in FIG. 4, the top surface side of the substantially cylindrical main body portion 12b is a flange portion 12d, and the flange portion 12d includes a first coupling and a bolt A second insertion hole 12f is provided for connecting at the same time. Furthermore, the dropout prevention member 14 supporting the stirring shaft 4 is provided with a notch 14b that engages with the key member 13.

  With respect to the stirring shaft 4 connected by the connecting structure according to the conventional example shown in FIG. 4, as shown in FIG. 5 (A), with respect to the outer peripheral surface of the portion near the proximal end 4b of the stirring shaft 4, As a result of applying a stress of 10000 N in the rotational direction, as shown in FIG. 5 (B), the minimum value of the safety factor at the root side of the bolt portion 4g was 1.89. Further, from the analysis result of the safety factor shown in FIG. 5 (B), the safety factor at the center side of the proximal end 4b of the stirring shaft 4 is particularly low, that is, the load load at the center side of the stirring shaft 4 is particularly large. I understand. The safety factor mentioned here indicates a value obtained by dividing the stress applied to the bolt portion 4g by the strength of the material of the stirring shaft 4.

On the other hand, in the example of the connecting structure 100 according to the embodiment of the present invention, as shown in FIG. 6A, the stirring shaft is used for the end face 40d of the proximal end 40b having an outer diameter of 184 mm. the proximal side of 40, the outer diameter of the bolt portion 40g of 36mm at a same distance from the center _{O a} of the end face 40d of the base end portion 40b, into three equal intervals so as to bypass the said center _{O a,} respectively Provided. That is, the ratio of the total of the cross-sectional area of the bolt portion 40g to the cross-sectional area of the stirring shaft 40 is 0.115. Then, with respect to the stirring shaft 40 connected by the connecting structure 100 according to the embodiment, as shown in FIG. 6A, rotation is performed with respect to the outer peripheral surface of the portion near the proximal end 40b of the stirring shaft 40. A stress of 10000 N was applied to the direction.

As a result, as shown in FIG. 6 (B), the minimum value of the safety factor at the root side of the bolt portion 40g is 3.03, which is about 1.5 times that of the conventional example. Further, from the analysis results of the safety factor shown in FIG. 6 (B), at a same distance bolt portion 40g so as to bypass the center O _A of the base end portion 40b of the stirring shaft 40 from the center O _A of the end surface 40d, It was found that since the plurality of parts were provided at equal intervals, the portion with low safety factor was dispersed, and then the minimum value of the safety factor was improved.

Therefore, at a same distance from the larger center O _A of the load during the operation of the base end portion 40b in particular stirrer 10 at the end face 40d of the stirring shaft 40 (see FIG. 1), bypassing the said center O _A, respectively Thus, it has been found that the load on the bolt portion 40g can be dispersed and the safety factor can be enhanced by providing the three bolt portions 40g so that the adjacent ones are equally spaced.

That is, even smaller than the conventional example the size of the bolt portion 40g, so as to bypass the center O _A of the end face 40d of the base end portion 40b of the stirring shaft 40 a plurality of bolt portion 40g of the above three, adjacent It was found that the strength against the load in the bending direction of the stirring shaft 40 can be strengthened by arranging the bolt portions 40 g to be equally spaced from each other. In particular, from the results of this embodiment, in order to strengthen the strength of the stirring shaft 40 in the bending direction, the ratio of the sum of the cross-sectional areas of the bolt portion 40g to the cross-sectional area of the stirring shaft 40 is 0.1 or more It has been found that even if the outer diameter of each bolt portion 40g is reduced, the strength against the load in the bending direction of the stirring shaft 40 is enhanced by increasing the number of the bolt portions 40g. For this reason, in the present embodiment, even if the outer diameter of the bolt portion 40g is reduced by increasing the number of the bolt portions 40g, the risk of breakage of the bolt portion 40g and the like is reduced and the dropping of the stirring shaft 40 is suppressed. It turned out that it can be done.

  Although one embodiment and examples of the present invention have been described in detail as described above, it is understood by those skilled in the art that many modifications can be made without departing substantially from the novel matters and effects of the present invention. It will be easy to understand. Accordingly, all such modifications are intended to be included within the scope of the present invention.

  For example, in the specification or the drawings, the terms described together with the broader or synonymous different terms at least once can be replaced with the different terms anywhere in the specification or the drawings. Further, the configuration and operation of the connection structure are not limited to those described in the embodiments of the present invention, and various modifications can be made.

DESCRIPTION OF SYMBOLS 10 stirrer, 30 tank, 31 tank main part, 32 lid part, 32a main surface, 33 through hole, 34 protection member, 40 stirring shaft, 40a tip, 40b base end, 40c taper part, 40d end face, 40e 1 vertical groove, 40f screw hole, 40g bolt part, 41 stirring blade, 50 drive part, 51 motor, 51a rotary shaft, 52 reduction mechanism, 52a drive shaft, 100 connection structure, 111 first coupling, 111a axis Hole 111b main body 111c flange 111d first insertion hole 112 second coupling 112a axial hole 112a1 outer edge 112b main body 112c one end 112d flange 112f second insertion hole , 112 g other end, 112 h abutment part, 113 key member, 113 a one end, 113 b insertion hole, 114 falling-off preventing member, 114 a penetration , 114b notch, 114c periphery 116 nut 117a bolts, 117b nuts, 118 volts, 119 volts, _{O A} (end face) center, (the stopper member) _{O B} center

Claims (4)

A connecting structure for connecting a stirring shaft to which a stirring blade of a stirrer is attached and a driving shaft of a drive unit,
A first coupling that rotates integrally with the drive shaft;
A second coupling having an axial hole fastened with the first coupling and through which the stirring shaft is inserted;
A through hole is formed in the end face of the proximal end of the stirring shaft, and a peripheral edge is engaged with the outer edge of the axial hole on the top surface side of the second coupling, A fall-off preventing member configured such that when the nut is tightened to the bolt portion penetrating the through hole, the base end portion is pressed toward the axial hole to restrict movement of the stirring shaft in the falling direction; Equipped
At least three or more of the bolt portions are provided on the end face of the proximal end portion of the stirring shaft so as to bypass the center of the end face, and the bolt portions are adjacent to each other at the same distance from the center The bolt parts are provided at equal intervals,
A connection structure body, wherein three or more of the through holes are provided at positions facing the bolt portions in the dropout preventing member.   The bolt portion is provided at a position closer to the outer edge of the end surface than the center of the end surface of the base end portion, and the through hole is closer to the outer edge of the falling-off member than the center of the drop prevention member The connection structure according to claim 1, wherein the connection structure is provided.   The connection structure according to claim 2, wherein the nut to be tightened to the bolt portion is provided such that an outer edge thereof is inside the peripheral edge portion of the fall-off preventing member.   In each bolt portion, adjacent bolt portions are equally spaced from each other by the same distance so that the ratio of the total of the cross sectional area of the bolt portion to the cross sectional area of the stirring shaft is 0.1 or more. The connection structure according to any one of claims 1 to 3, which is provided.

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