Mechanically fixed stud bolt device

Abstract

To provide a stud bolt capable of being mechanically fixed with shear torque without requiring a fine thread or tightening tolerance as specified in the JIS standard.SOLUTION: A stud bolt has: a flange that is perpendicular to an axis at a middle position of the stud bolt and has a thickness with a polygonal outer peripheral surface; a cylindrical sleeve with an eccentric hole that is located eccentrically from a center of a circle and having a polygonal hole of the same shape as the flange of the stud bolt; and a female screw part having a circular counterbore at the same eccentricity from a female screw as the sleeve with the eccentric hole. The counterbore and the sleeve with the eccentric hole are engaged, the sleeve with the eccentric hole functions as a key function, and the counterbore functions as a key groove function, thereby securing the stud bolt.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a stud bolt.

Background Art

[0002] Conventionally, as disclosed in Patent Document 1 below, by inserting a plate 9 into the flange portion 3 of the stud bolt 7 from the axial direction, the rotation of the flange bolt 7 is synchronized with the plate 9, and a stopper 11 formed on the plate 9 is always brought into contact with a stopper 10 protruding from the member to be fixed 8 with a movement less than one rotation of the stud bolt, or a plate 9r is inserted into the stud bolt 7 screwed into the groove portion 20r, and a stopper 18r of the stud bolt 7 is always brought into contact with a stopper 19r with a movement less than one rotation of the stud bolt.

[0003] Also, as shown in Non-Patent Document 1 below, the thread on the implanting side of the stud bolt tap of JIS B1173-2015 has a tolerance of 6g defined in JISB20209-3, and has an interference tolerance with the female thread on the implanting side, and a screwing torque is applied to the stud bolt for screwing. This screwing torque was to prevent the stud bolt from loosening.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem to be solved by the present invention is that, in a form where the plate 9 is inserted axially into the flange portion 3 of the stud bolt 7 in Patent Document 1 above, the rotation of the flange bolt 7 is synchronized with the plate 9, and the stopper 11 formed on the plate 9 abuts against the stopper 10 protruding from the member to be fixed 8 and always abuts against the stopper with a movement less than one rotation of the stud bolt. In this form, since the stopper 10 has a special shape and it is also necessary to attach it to the member to be fixed 8, the cost is high. Furthermore, due to the rotation of the stud bolt 7 being less than one rotation, the tightening axial force of the stud bolt 7 decreases. The object is to provide a non-rotating stud bolt that can solve this problem.

[0007] Also, in Patent Document 1 above, by inserting the plate 9 axially into the flange portion 3 of the stud bolt 7, the rotation of the flange bolt 7 is synchronized with the plate 9. Even in a form where the plate 9r is inserted into the stud bolt 7 screwed into the groove portion 20r and the stopper 18r of the stud bolt 7 always abuts against the stopper 19r with a movement less than one rotation of the stud bolt, since the stopper 10 has a special shape, the manufacturing cost increases. Furthermore, due to the rotation of the stud bolt 7 being less than one rotation, the tightening axial force of the stud bolt 7 decreases. The object is to provide a non-rotating stud bolt that can solve this problem.

[0008] Also, the embedded bolt (stud bolt) in Non-Patent Document 1 above has a female thread on the embedded side with a dimensional tolerance. Therefore, there are problems such as rotating and loosening within the tolerance range, or conversely, twisting and breaking during removal work, making it difficult to remove the damaged embedded bolt. Also, in an engine made of aluminum alloy, there is concern about insufficient screw strength. The object is to provide a stud bolt that is easy to attach and remove and has sufficient strength. Means for Solving the Invention

[0009] The mechanical fixed stud bolt device of the present invention made to solve the above problems has a flange with an inscribed circle of a polygonal surface larger than the diameter of the screw, where the outer shape of the axial cross-section is formed by a plurality of straight lines or curves with a thickness of about 4 screw pitches in the axial direction between the screw on the implant side and the screw on the tightening side. It consists of a stud bolt, an eccentric hole sleeve with a hole core having the same shape as the polygonal surface of the flange at a position eccentric by several millimeters from the core of the cylinder, which is cylindrical and about 1 screw pitch thicker than the thickness of the flange, and having the same thickness as the depth of the counterbore, and a female screw part having a counterbore with the same depth as the thickness of the eccentric hole sleeve from the core of the female screw to the core of the polygonal surface of the eccentric hole sleeve. The counterbore is a key groove and the eccentric hole sleeve functions as a key to fix it mechanically.

[0010] The installation of the mechanical fixed stud bolt device of the present invention is as follows: First, screw in the screw on the implant side of the stud bolt until it touches the bottom surface of the counterbore where the implant screw side surface of the flange is eccentric. Roughly align the direction of the tangent where the polygonal surface of the flange intersects with the direction from the core of the female screw to the core of the eccentric counterbore. Next, insert 3 holes of the polygonal surface of the eccentric sleeve into the stud bolt. Align the circular positions of the outer peripheral surface of the eccentric hole sleeve and the inner peripheral surface of the counterbore part, and push the implant screw side surface of the hole sleeve until it adheres to the tightening screw side surface of the flange of the stud bolt. Then, while rotating the stud bolt in the loosening direction, finely adjust it left and right at the front and rear angles obtained by dividing 360 degrees by the number of sides of the polygonal surface of the flange, and rotate it to make the polygonal hole surface of the eccentric hole sleeve coincide with the polygonal flange surface of the stud bolt. After that, push the female screw side surface of the eccentric hole sleeve until it adheres to the bottom surface of the counterbore and engage it to fix it mechanically.

[0011] When the pitch of the screw of M2 is 1.75 mm and the number of faces of the polygon is 6, the axial movement amount when the stud bolt is rotated to align the counterbore of the female screw portion with the eccentric direction of the eccentric hole sleeve is approximately 0.3 mm obtained by dividing the pitch of 1.75 mm by 6. If the depth of the counterbore surface is approximately one screw pitch deeper than the thickness of the flange of the stud bolt, the flange does not protrude from the seating surface and the circular hole positions of the counterbore and the eccentric hole sleeve are aligned.

[0012] The stud bolt has a thickness of approximately four screw pitches in the axial direction between the screw on the implant side and the screw on the tightening side, and has a flange with a polygonal surface whose outer shape in the cross-section perpendicular to the axis is formed by a plurality of straight lines or curves and whose inscribed circle of the outer shape is larger than the diameter of the screw. By engaging the eccentric hole sleeve with the female screw portion, the removal torque of the screw can be made equal to or greater than the shear torque without using the fine thread or interference tolerance specified by the JIS standard for the screw on the implant side.

[0013] The eccentric hole sleeve has a circular outer shape and is approximately one screw pitch thicker than the thickness of the flange of the stud bolt. There is a hole core with the same shape as the flange at a position eccentric by several millimeters from the center of the circle. By engaging with the flange and being inserted into the counterbore to exert a key function, the stud bolt is mechanically fixed by the torque obtained by multiplying the eccentricity amount by the diameter of the eccentric hole sleeve, the flange thickness, and the allowable surface pressure of the stud bolt material. There may be a tapping screw for removal.

[0014] The female screw portion is composed of a counterbore having an inner peripheral surface that engages with the outer peripheral surface 3 of the eccentric hole sleeve at the same depth as the thickness of the eccentric hole sleeve at the same eccentric distance from the female screw to the core of the cylinder of the eccentric hole sleeve and the core of the hole of the polygonal surface. The counterbore exerts a key groove function, and the stud bolt is mechanically fixed by the torque obtained by multiplying the eccentricity amount by the diameter of the eccentric hole sleeve, the flange thickness, and the allowable surface pressure of the stud bolt material.

Advantages of the Invention

[0015] According to the mechanical fixed stud bolt device of the present invention, the return torque can be made greater than the shear torque of the screw by the key and keyway effect.

Brief Description of the Drawings

[0016]

Figure 1

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Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the completion of mounting of the mechanical fixed stud bolt according to an embodiment of the present invention, FIG. 2 is a cross-sectional view in the direction of the arrow of the female screw part composed of a female screw and a counterbore, FIG. 3 is a cross-sectional view in the direction of the arrow with the flange surface of the stud bolt screwed into the counterbore surface, FIG. 4 is a cross-sectional view in the direction of the arrow with the tip of the sleeve with an eccentric hole partially inserted into the counterbore, FIG. 5 is a view of the stud bolt with a multi-faceted flange, FIG. 6 is a view of the sleeve with a multi-faceted eccentric hole, FIG. 7 is a view in the direction of the arrow of the cross-section line “A - A”, FIG. 8 is a view in the direction of the arrow of the cross-section line “B - B”, FIG. 9 is a view in the direction of the arrow of the cross-section line “C - C”, and FIG. 10 is a view showing the form of the cross-section line “D - D” in the direction of the arrow.

[0018] In the mechanical fixing stud bolt device of the present invention, between the screw 22 on the implant side and the screw 23 on the tightening side, there is a polygonal surface 24 with an outer shape in a cross-section perpendicular to the axis having a thickness of about 4 screw pitches in the axial direction and formed by a plurality of straight lines or curves. The stud bolt 20 has a flange 21 in which the inscribed circle of the surface 24 is larger than the diameter of the screw. The sleeve 30 with an eccentric hole has a cylindrical shape, is about 1 screw pitch thicker than the thickness of the flange 21, and has a core 27 of a hole with the same shape as the polygonal surface 24 of the flange 21 at a position eccentric by several millimeters from the core 28 of the cylinder. It has the same thickness as the depth of the surface 12 of the counterbore 11 and the thickness of the surfaces 32 and 33. The female screw part 10 has a counterbore 11 with the same eccentricity distance from the core 27 of the female screw 14 to the core 28 of the cylinder of the sleeve 30 with an eccentric hole and the core 27 of the polygonal surface 34 and the same depth as the thickness of the sleeve 30 with an eccentric hole. The counterbore has a key groove and the sleeve with an eccentric hole exerts a key function to mechanically fix the stud bolt 20.

[0019] The installation of the mechanical fixing stud bolt device of the present invention is as follows: First, screw in the implant side screw 22 of the stud bolt 20 until it abuts against the bottom surface 12 of the counterbore 11 where the implant screw side surface 25 of the flange 21 is eccentric. Roughly align the direction of the tangent where the polygonal surface 24 of the flange 21 intersects with the direction from the core 27 of the female screw 14 to the core 28 of the eccentric counterbore 11. Next, insert the hole of the polygonal surface 34 of the eccentric sleeve 30 into the stud bolt 20, align the circular positions of the outer peripheral surface 31 of the sleeve 30 with an eccentric hole and the inner peripheral surface 13 of the counterbore part 10, and push the surface 32 on the implant screw 22 side of the sleeve 30 with a hole until it adheres to the surface 26 on the tightening screw 23 side of the flange 21 of the stud bolt 20. Subsequently, rotate the stud bolt 20 while finely adjusting it left and right at the front and rear angles obtained by dividing 360 degrees in the loosening direction by the number of sides of the polygonal surface 24 of the flange 21. After aligning the polygonal hole surface 34 of the sleeve 30 with an eccentric hole and the polygonal flange 21 surface 24 of the stud bolt 20, push the surface 32 on the female screw 14 side of the sleeve 30 with an eccentric hole until it adheres to the bottom surface 12 of the counterbore 11 and engages to mechanically fix the stud bolt 20.

[0020] When the pitch of the screw of M2 is 1.75 mm and the number of faces of the polygon is 6, the axial movement amount required to rotate the stud bolt 20 to align the counterbore 11 of the female screw portion 10 with the eccentric direction of the sleeve 30 with an eccentric hole is about 0.3 mm obtained by dividing the pitch 1.75 mm by 6. Therefore, if the depth of the surface 12 of the counterbore 11 is about one screw pitch deeper than the thickness of the flange 21 of the stud bolt 20, the flange 21 will not protrude and the circular hole positions of the counterbore 11 and the sleeve 30 with an eccentric hole will be aligned.

[0021] The stud bolt 20 has a thickness of about four screw pitches in the axial direction between the screw 22 on the implant side and the screw 23 on the tightening side, and has a flange 21 with a polygonal surface 24 whose outer shape in the cross-section perpendicular to the axis is formed by a plurality of straight lines or curves and the inscribed circle of the outer shape is larger than the diameter of the screw. By engaging the sleeve 30 with an eccentric hole and the female screw portion 10, the removal torque of the screw can be made equal to or greater than the shear torque without using the fine thread or interference tolerance defined by the JIS standard for the screw 22 on the implant side.

[0022] The sleeve 20 with an eccentric hole has a circular outer shape and is about one screw pitch thicker than the thickness of the flange 21 of the stud bolt 20. There is a hole center 27 with the same shape as the flange 21 at a position eccentric by several millimeters from the center of the circle. By engaging with the flange 21 and being inserted into the counterbore 11 to exert a key function, the stud bolt 20 is mechanically fixed with a torque obtained by multiplying the eccentricity amount by the diameter of the sleeve 20 with an eccentric hole, the thickness of the flange 21, and the allowable surface pressure of the material of the stud bolt 20. There may be a tapping screw 35 for removal.

[0023] The female screw part 10 is composed of a seat grooving 11 having a circumferential surface 13 that engages with the outer peripheral surface 31 of the eccentric-hole sleeve 30 at the same depth as the thickness of the surfaces 32 and 33 of the eccentric-hole sleeve 30, at the same eccentric distance from the female screw 14 to the core 28 of the cylinder of the eccentric-hole sleeve 30 with an eccentric hole and the core 27 of the polygonal surface 34. The seat grooving 11 exhibits a keyway function and mechanically fixes the stud bolt with a torque obtained by multiplying the diameter of the eccentric-hole sleeve 20, the thickness of the flange 21, and the allowable surface pressure of the stud bolt material by the eccentricity amount.

Explanation of Signs

[0024] 10 Female screw part 11 Seat grooving 12 Surface 13 Circumferential surface 14 Female screw 15 Center line 16 Center line 20 Stud bolt 21 Flange 22 Screw 23 Screw 24 Surface 25 Surface 26 Surface 27 Core 28 Core 30 Eccentric-hole sleeve 31 Surface 32 Surface 33 Surface 34 Surface 35 Tap drill

Claims

1. A stud bolt having a flange with an axial thickness of approximately four screw pitches between the implant side screw and the tightening side screw, and a polygonal surface formed by a plurality of straight lines or curves in the cross-section perpendicular to the axis, with the inscribed circle of the polygonal surface being larger than the diameter of the screw; an eccentric hole sleeve having a cylindrical shape, approximately one screw pitch thicker than the thickness of the flange, with a hole core having the same shape as the polygonal surface of the flange at a position eccentric by several millimeters from the core of the cylinder and having the same thickness as the depth of the counterbore surface; and a female screw portion having a counterbore with a depth equal to the thickness of the eccentric hole sleeve from the core of the female screw to the core of the polygonal surface of the eccentric hole sleeve, and the counterbore being a key groove and the eccentric hole sleeve functioning as a key to mechanically fix the stud bolt.

2. The installation of the mechanical fixing stud bolt device of the present invention is as follows: First, screw in the implant side screw of the stud bolt until it touches the bottom surface of the counterbore where the implant screw side surface of the flange is eccentric. Roughly align the direction of the tangent where the polygonal surface of the flange intersects with the direction from the core of the female screw to the core of the eccentric counterbore. Next, insert the stud bolt into the hole of the polygonal surface of the eccentric sleeve, align the circular positions of the outer peripheral surface of the eccentric hole sleeve and the inner peripheral surface of the counterbore portion, and push it in until the implant screw side surface of the hole sleeve adheres to the tightening screw side surface of the flange of the stud bolt. Subsequently, rotate the stud bolt while finely adjusting it left and right at the front and rear angles obtained by dividing 360 degrees in the loosening direction by the number of sides of the polygonal surface of the flange to align the polygonal hole surface of the eccentric hole sleeve with the polygonal flange surface of the stud bolt. Then, push the female screw side surface of the eccentric hole sleeve to the bottom surface of the counterbore and adhere and engage it to mechanically fix the stud bolt as claimed in claim 1.

3. By engaging the eccentric hole sleeve and the female screw portion with a flange having an axial thickness of approximately four screw pitches between the implant side screw and the tightening side screw, and a polygonal surface formed by a plurality of straight lines or curves in the cross-section perpendicular to the axis, with the inscribed circle of the outer shape being larger than the diameter of the screw, the removal torque of the screw can be made greater than or equal to the shear torque even for fine threads or interference tolerances defined by JIS standards for the implant side screw. The mechanical fixing stud bolt as claimed in claim 1.

4. The outer shape is circular, about one screw pitch thicker than the thickness of the flange of the stud bolt, and there is a hole core with the same shape as the flange at a position eccentric by several millimeters from the center of the circle. By engaging with the flange and being inserted into the counterbore to perform the key function, it has an eccentric-hole sleeve that exhibits the function of mechanically fixing the stud bolt with a torque obtained by multiplying the eccentricity by the diameter of the eccentric-hole sleeve, the flange thickness, and the allowable bearing pressure of the stud bolt material. The mechanical fixing stud bolt according to claim 1.

5. The female thread portion is composed of a counterbore having a circumferential surface that engages with the outer peripheral surface of the eccentric-hole sleeve at the same depth as the thickness of the eccentric-hole sleeve at the same eccentric distance from the female thread to the center of the cylinder of the eccentric-hole sleeve and the center of the hole of the polygonal surface. The counterbore exhibits the key groove function and mechanically fixes with a torque obtained by multiplying the eccentricity by the diameter of the eccentric-hole sleeve, the flange thickness, and the allowable bearing pressure of the stud bolt material. The mechanical fixing stud bolt according to claim 1.

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