JP2006116668A - Female screw repair tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a female screw repair tool, easily mending a thread of a female screw using a hand driver or the like without requiring skill. <P>SOLUTION: Since the outside diameter d, the effective diameter d<SB>2</SB>and the root diameter d<SB>1</SB>of a male screw 22 engaged with the female screw to mend the thread are equal to or less than the upper limit value E2max of an allowance of an assembling male screw engaged with the female screw and also equal to or more than [E2max-60 μmm], the mending male screw 22 is passed with play in a thread groove of the female screw, whereby the mending male screw 22 is restrained from biting in the female screw to facilitate mending work. Since the mending male screw 22 has a size approximating to the upper limit value E2max of the allowance of the assembling male screw , the mending male screw 22 is engaged with the female screw to mend the thread, whereby an assembling male screw approximating to the upper limit value E2max of the allowance as well as an assembling male screw approximating to the lower limit value E2min of the allowance can be preferably engaged with the female screw. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a female screw retouching tool for adjusting a thread of a female screw by being screwed to the female screw.

If the screw cannot be screwed because it is fixed by welding and spatter adheres to the screw, or if the screw thread bites into the female screw and the female screw thread is crushed In general, for example, a tapping process of a female screw is performed again by using a normal cutting tap described in Patent Document 1 or the like to correct the thread of the female screw.
Utility Model Registration No. 3005741

  By the way, such a female screw retouching operation is performed manually using an electric or air-driven hand driver, and the cutting tap is fed while the hand driver is being fed with the progress of screwing between the cutting tap and the female screw. It is necessary to screw into the female screw, but if the feed of the hand driver is misaligned, the cutting edge of the tap may bite into the female screw and the thread may be thinned or the tap may be broken. There was a problem that it took.

  The present invention has been made against the background of the above circumstances, and the purpose of the present invention is to repair a female screw that can be easily modified using a hand driver or the like without requiring skill. To provide a tool.

  In order to achieve such an object, the first invention is a female screw retouching tool for adjusting a thread of a female screw by being screwed to the female screw, and (a) a modification having the same pitch as that of the female screw. (B) the outer diameter, the effective diameter, and the root diameter of the modification male screw are larger than the lower limit value of the tolerance of the assembled male screw to be screwed into the female screw, respectively. It is characterized by being smaller than the standard angle of the assembled male screw.

  Here, the outer diameter, the effective diameter, and the valley diameter are all diameters, and the lower limit value of the tolerance is the outer diameter, the effective diameter, and the valley diameter defined by the standards such as JIS for the assembled male screw. This is the minimum allowable dimension, and the outer diameter, effective diameter, and trough diameter of the modification male screw are all larger than the minimum allowable dimension. In addition, the standard thread shape of the assembled male thread is also defined by standards such as JIS, etc., and is defined for the standard diameter of the outer diameter, the standard dimension of the effective diameter, and the standard dimension of the valley diameter, The external diameter, effective diameter, and trough diameter of the modifying male screw are all smaller than the reference dimension.

  The second invention is the female screw rework tool according to the first invention, wherein the external diameter, effective diameter, and trough diameter of the male screw for modification are each not more than the upper limit of the tolerance of the assembled male screw, and The outer diameter and the effective diameter are not less than [the upper limit value−60 μm].

  That is, the upper limit of the tolerance is the maximum allowable dimension of the outer diameter, effective diameter, and valley diameter determined by the standards of JIS etc. for the assembled male thread, and the outer diameter, effective diameter, In addition, the diameter of the valley and the valley are both equal to or smaller than the maximum allowable dimension, and the outer diameter and the effective diameter are equal to or larger than the diameter dimension obtained by subtracting 60 μm from the maximum allowable dimension. Note that, depending on the diameter size, accuracy, and standard of the assembled male screw, the reference angle may coincide with the upper limit value (maximum allowable dimension) of tolerance.

  According to a third aspect of the present invention, in the female screw rework tool according to the first or second aspect of the present invention, the modification male screw is divided in the circumferential direction to form a plurality of lands, and is screwed into the female screw of the land. The rake angle of the leading edge to be made negative is negative.

  4th invention is the internal thread screw repair tool of 3rd invention, The rake angle of the peak part in the said leading side edge is in the range of -20 degrees--60 degrees, The relief angle of the leading side edge is 0 degree. The diameter dimension of the land is constant.

  According to a fifth aspect of the invention, there is provided a female screw rework tool according to the third or fourth aspect of the present invention, wherein a plurality of corners have a regular polygonal column shape centered on an axis, and the arc corners thereof. Functions as the land, and the correction male screw is provided.

  In such a female screw repair tool, the external diameter, effective diameter, and trough diameter of the male thread for repair provided at the same pitch as the female thread are all from the standard thread shape (each standard dimension) of the assembled male thread. Because of its small size, the modification male screw has a smaller diameter than the female screw, and the modification male screw can pass through the thread groove of the female screw with play, and the modification male screw may bite into the female screw. As a result, the female screw can be easily repaired. In addition, the external diameter, effective diameter, and valley diameter of the male thread for modification are larger than the lower limit of tolerance (each minimum allowable dimension) of the assembled male thread screwed into the female thread. By screwing into the internal thread, at least the assembled male thread near the lower limit of the tolerance can be screwed in without interfering with the female thread, and the assembled male thread with a larger diameter (such as near the upper limit of the tolerance) In addition, although there is a possibility of causing some interference, it can be screwed in without causing poor screwing.

  In the second invention, the external diameter, effective diameter, and valley diameter of the male thread for modification are not more than the upper limit of tolerance of each assembled male thread (each maximum allowable dimension), and the external diameter and effective diameter are The upper limit value is -60 μm], that is, the size is close to the upper limit value of the tolerance of the built-in male screw. It can be screwed well with almost no interference.

  The third invention is a case where the male thread for modification is divided in the circumferential direction to form a plurality of lands, and since the rake angle of the leading edge of the land is negative, the thread of the female thread is While the modification is mainly performed by plastic deformation, the biting of the female screw is further prevented, and the modification work can be easily performed without requiring skill. Spatter and the like adhering to the female screw during welding may be removed not only by plastic deformation but also from the female screw by being rubbed by the modifying male screw. It is accommodated in the groove between and discharged.

  In the fourth invention, since the rake angle of the peak portion at the leading edge is within a range of −20 ° to −60 °, the biting against the female screw is further prevented, and the clearance of the leading edge is prevented. Since the angle is 0 ° and the diameter of the land is constant, a female thread retouching tool can be manufactured easily and inexpensively.

  The female thread retouch tool according to the fifth aspect of the present invention has a regular polygonal column shape having an arc corner, and the arc corner functions as a land and is provided with a correction male screw. Manufactured inexpensively.

  The female thread retouching tool of the present invention is used by being attached to a hand driver such as an electric type or an air driven type, for example, and while holding the hand driver by hand while rotating at a predetermined rotational speed such as 6000 r / min. The thread of the female thread can be modified by screwing the male thread for modification into the female thread. The female thread retouching tool is configured to have a shank or the like coaxially with the modifying external thread.

  In the second invention, the external diameter and effective diameter of the male thread for modification are not more than the upper limit of the tolerance of the assembled male screw and not less than [the upper limit value −60 μm], but in carrying out the first invention, Appropriately within a range that is larger than the lower limit value of the tolerance of the assembled male screw and smaller than the standard mountain shape, such as may be set within a range smaller than the standard male shape of the assembled male screw and [the upper limit of tolerance-60 μm]. Can be determined. The root diameter of the male thread for modification is also set within the upper limit of the tolerance of the assembled male screw and within the range of [the upper limit value −60 μm] or smaller than the reference thread shape of the assembled male screw and [ Various modes are possible, such as setting within a range of an upper limit of tolerance −60 μm] or more.

  For the outer diameter, effective diameter, and trough diameter of the assembled male screw, call the upper limit (maximum allowable dimension) and the lower limit (minimum allowable dimension) according to, for example, JIS B0209 (diameter dimension) and grade (accuracy). ) Are defined, and the outer diameter, effective diameter, and trough diameter of the modification external thread are set based on the standard of such assembly external threads.

  For example, the male screw for modification is configured to have a complete crest and a chamfered portion whose outer diameter is tapered to a small diameter, but it may be a complete crest or a tip of a complete crest. For example, only chamfering of about 45 ° may be applied.

  The modifying external thread is divided by, for example, providing a groove in the axial direction to form one or a plurality of lands, and the groove may be a straight groove or a twisted groove. The flat side surface of the regular polygonal column shape of the fifth invention corresponds to a straight groove, but a groove having a circular arc shape at the groove bottom can also be provided. When dividing into 3 to 5 lands, the land width (center angle) is preferably in the range of about 20 ° to 40 °, for example, and the groove bottom diameter (core thickness) is the outer diameter of the male screw for modification. A range of about 0.6d to 0.8d with respect to d is appropriate.

  When the rake angle of the leading edge is negative, the female screw is modified mainly by plastic deformation by screwing in the modifying male screw, but the degree of deformation of the female screw, the state of adhesion of spatter, etc., or rake Depending on the size of the corner, it can be modified with cutting, turning, spattering and other deposits.

  Since the male thread for modification of the present invention needs to be reversely rotated and pulled out from the female screw after screwing into the female screw and modifying the screw thread, the heel side opposite to the leading edge is also the leading side. As with the edge, it is desirable that the rake angle during reverse rotation be negative (for example, −20 ° to −60 °), and for example, it is configured symmetrically with the leading edge.

  Since the female thread retouching tool of the present invention is not intended for cutting, even when a chamfer is provided, the clearance angle can be set to 0 ° as in the fourth aspect, and the land diameter can be made constant. It is also possible to provide a predetermined relief at the biting portion or the complete mountain portion.

  As the regular polygonal column of the fifth invention, for example, a regular triangular prism, a regular quadrangular column, and a regular pentagonal column are suitably employed as tools, but it is also possible to use a regular polygonal column greater than a regular hexagonal column.

  As the tool material of the female screw rework tool of the present invention, various metal materials such as steel such as high speed tool steel and alloy tool steel, or cemented carbide can be adopted. If necessary, it is possible to coat a hard film such as TiAlN or perform a surface hardening treatment such as carburization.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIGS. 1A and 1B are views for explaining a female screw reworking tool 10 according to an embodiment of the present invention, in which FIG. 1A is a front view seen from a direction perpendicular to the axis, and FIG. Sectional view (c) is a view for explaining the thread shape and tolerance, and is a view corresponding to a section including the axis O. The female screw reworking tool 10 includes a shank 12 and a threaded portion 14 which are coaxially integrated, and the shank 12 is attached to a main shaft of an air-driven hand driver 30 shown in FIG. The screw thread of the female screw 18 is modified by being screwed into the female screw 18 of the nut 16 while being rotationally driven. The nut 16 is fixed to the panel 20 or the like by welding or the like. When the assembled male screw such as a bolt is screwed, the nut 16 cannot be screwed due to adhesion of spatter or the like. The internal thread 18 bites and the screw thread of the female screw 18 is crushed. The hand driver 30 is one in which an operator grips the grip 32 and manually moves the hand screw 30. The hand screw 30 is fed while the hand driver 30 is being fed with the progress of the screwing of the female screw correcting tool 10 and the female screw 18. While it is necessary to screw the tool 10 into the female screw 18, the female screw repairing tool 10 is screwed into the female screw 18 to correct the thread, and then the female screw repairing tool 10 is pulled while pulling the hand driver 30. Needs to be reversely rotated and extracted from the female screw 18.

The threaded portion 14 is provided with a modification male screw 22. The external thread 22 for modification is threaded at the same pitch as the internal thread 18, and its outer diameter d, effective diameter d ₂ , and trough diameter d ₁ should be screwed into the nut 16. It is set based on the same standard (JIS etc.) as the assembly male screw. Specifically, in FIG. 1 (c), the area E1 indicated by the oblique line is the tolerance area (allowable area) of the internal thread 18, and the reference angle 24 is defined as the lower limit (minimum allowable dimension). The outer diameter d and the effective diameter d _{2 of the} male screw 22 for modification are defined in the tolerance range (allowable range) of the assembled male screw to be screwed to the female screw 18 and smaller than the reference angle 24. As shown by the arrow A, the diameter d ₁ of the valley is smaller than the reference chevron 24 and larger than the lower limit E2min of the tolerance range E2 of the assembled male screw. In this embodiment, the upper limit of the tolerance range E2 It is determined within the range of not more than the value E2max and not less than [E2max−60 μm]. These tolerance areas E1 and E2 are determined according to the nominal (diameter dimension) and grade (accuracy) in, for example, JIS B0209, and the upper limit value E2max corresponds to the maximum allowable dimension, and the lower limit value E2min is Corresponds to the minimum allowable dimension. Further, the reference angle 24 corresponds to the reference angle of the assembled male screw, and in this embodiment coincides with the reference angle of the internal thread 18. Note that the female screw rework tool 10 of the present embodiment relates to a screw having a nominal size of M10 × 1.25, for example.

  Here, the tap for processing the internal thread 18 is determined within the tolerance range E1 of the internal thread 18, but there is no play when the internal thread 18 is repaired using the same tap. The tap may bite into the flank of the female screw 18 and the thread may be thinned or the tap may be broken. Further, if the nut 16 becomes unusable due to a bevel of the internal thread 18 or the like, it is necessary to replace the entire set including the panel 20, which increases the number of steps and causes a cost increase. For this reason, in this embodiment, a female screw retouching tool 10 is prepared which has a retouching male screw 22 within the tolerance range E2 of the assembling male screw, and the retouching male screw 22 has play. By being screwed onto the female screw 18, the female screw 18 can be easily modified.

The screw portion 14 is composed of a complete crest portion and a chamfered portion of about 5 crests whose outer diameter d is tapered to a small diameter, and as is apparent from FIG. Four straight grooves 26 are provided at equal angular intervals around O, and the modification male screw 22 is divided into four lands 28. The straight groove 26 has an arc-shaped groove bottom, the radius R of which is about 0.4d with respect to the outer diameter d, the land width (center angle) γ of the land 28 is about 30 °, and the groove bottom diameter d. _M is about 0.7 d, and the rake angle θ of the peak portion of the leading edge 28a is about −30 °. The clearance angle of the leading side edge 28a is 0 ° including the chamfered portion, the land 28 is provided with a constant diameter from the leading side edge 28a to the heel 28b in the circumferential direction, and the heel 28b is Around the axis O, it is configured symmetrically with the leading edge 28a. FIG. 1B is a cross-sectional view taken along the thread of the modification male screw 22.

According to the female screw repairing tool 10 as described above, the external diameter d, the effective diameter d ₂ , and the trough diameter d _{1 of} the modifying external thread 22 provided at the same pitch as the internal thread 18 are the assembled external threads. In this embodiment, since the tolerance is smaller than the upper limit value E2max of the assembled male screw, the modification male screw 22 has a smaller diameter than the female screw 18 and the thread groove of the female screw 18 is smaller. The modification male screw 22 is allowed to pass therethrough with play, and the modification male screw 22 is prevented from biting into the female screw 18 so that the female screw 18 can be easily modified. become.

Further, the outer diameter d, the effective diameter d ₂ , and the valley diameter d ₁ of the modification male screw 22 are larger than the lower limit value E2min of the tolerance of the assembled male screw screwed to the female screw 18, and in this embodiment, Since the diameter is obtained by subtracting 60 μm from the upper limit E2max [E2max −60 μm] or more, the modification male screw 22 is eventually set to a size near the upper limit E2max of the tolerance of the assembled male screw. When the thread of the female screw 18 is adjusted by being screwed onto the screw 18, not only the assembled male screw near the lower limit value E2min of the tolerance but also the assembled male screw near the upper limit value E2max of the female Thus, it can be screwed in well with almost no interference.

  In the present embodiment, since the rake angle θ of the leading edge 28a of the land 28 is about −30 °, the thread of the female screw 18 is modified mainly by plastic deformation, and the female screw 18 is modified. The biting of the male screw 22 can be prevented more satisfactorily, and the repair work can be easily performed without requiring skill. Spatter and the like adhering to the internal thread 18 during welding may be removed not only by plastic deformation but also falling off the internal thread 18 by being rubbed by the modifying external thread 22. It is accommodated in the straight groove 26 and discharged.

  In the present embodiment, the clearance angle of the leading edge 28a is 0 ° including the chamfered portion, and the land 28 is provided with a constant diameter, so that the internal thread retouching tool 10 can be manufactured easily and inexpensively.

  In the above embodiment, the chamfered portion is provided at the tip of the screw portion 14, but the chamfered portion is omitted as shown in FIG. 3, and only a chamfer 40 of about 45 ° is applied to the tip of the complete mountain portion. But it ’s okay.

4 (a) to 4 (c) are cross-sectional views corresponding to FIG. 1 (b) when the shape of the screw portion 14 is different. (a) Or it is determined appropriately as shown in FIG. 4A has a substantially regular quadrangular prism shape, and the four corners have an arc shape with the axis O as the center, and the arc corners serve as lands 44. The above-described modification male screw 22 is provided. The four side surfaces 46 in this case correspond to four straight grooves having a flat groove bottom, the land width (center angle) γ of the land 44 is about 20 °, and the groove bottom diameter d _M is about 0.8d. The rake angle θ of the peak portion of the side edge 44a is about −55 °. The clearance angle of the leading edge 44a is 0 °, and the land 44 is provided with a constant diameter from the leading edge 44a to the heel 44b in the circumferential direction. The heel 44b is leading around the axis O. It is configured symmetrically with the side edge 44a. In the present embodiment, in addition to the same effects as those of the previous embodiment, the screw portion 42 has a substantially regular polygonal column shape, and the arc corner portion functions as a land 44 for modification. Since the screw 22 is provided, the screw 22 is manufactured more easily and inexpensively.

The threaded portion 50 in FIG. 4B has a substantially regular triangular prism shape, and has three corners in an arc shape with the axis O as the center, and the arc corners serve as lands 52. The above-described modification male screw 22 is provided. In this case, the three side surfaces 54 correspond to three straight grooves having a flat groove bottom, the land width (center angle) γ of the land 52 is about 30 °, the groove bottom diameter d _M is about 0.7 d, and leading The rake angle θ of the peak portion of the side edge 52a is about −45 °. The clearance angle of the leading edge 52a is 0 °, and the land 52 is provided with a constant diameter from the leading edge 52a to the heel 52b in the circumferential direction. The heel 52b is leading around the axis O. It is configured symmetrically with the side edge 52a. Also in this case, the same effect as the embodiment of FIG. 4 (a) can be obtained.

4 (c) is a case where three lands 64 are provided by three straight grooves 62 having a groove bottom having an arc shape, and the modification male screw 22 is provided on the land 64. As shown in FIG. It has been. The land width (center angle) γ of the land 64 is about 30 °, the groove bottom diameter d _M is about 0.6d, and the rake angle θ of the peak portion of the leading edge 64a is about −20 °. Further, the clearance angle of the leading edge 64a is 0 °, and the land 64 is provided with a constant diameter from the leading edge 64a to the heel 64b in the circumferential direction, and the heel 64b is leading around the axis O. It is configured symmetrically with the side edge 64a. In this case, the same effect as the embodiment of FIG. 1 can be obtained.

  As mentioned above, although the Example of this invention was described in detail based on drawing, these are one embodiment to the last, and this invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the internal thread tool repair tool which is one Example of this invention, (a) is a front view, (b) is BB sectional drawing in (a), (c) is for the repair provided in a screw part. It is a figure explaining the dimension of a male screw. It is a figure explaining the usage method of the tool for female screw repair of FIG. This is a case where the chamfered portion is omitted in the internal thread repair tool of FIG. FIG. 5 is a diagram for explaining another embodiment of the present invention, and each is a cross-sectional view corresponding to FIG.

Explanation of symbols

  10: Female screw retouching tool 18: Female screw 22: Modification male screw 24: Reference thread (reference thread for assembly male thread) 28, 44, 52, 64: Land 28a, 44a, 52a, 64a: Leading edge θ: Rake angle E2: Tolerance range of assembly male screw E2max: Upper limit of tolerance E2min: Lower limit of tolerance

Claims (5)

A female screw retouching tool that adjusts the thread of the female screw by being screwed to the female screw,
While having a male screw for modification of the same pitch as the female screw,
The external diameter, effective diameter, and valley diameter of the male thread for modification are larger than the lower limit value of the tolerance of the assembled male thread screwed into the female thread and smaller than the standard thread shape of the assembled male thread. A female screw rework tool characterized by The external diameter, effective diameter, and trough diameter of the modification male screw are each not more than the upper limit of tolerance of the assembled male screw, and the outer diameter and effective diameter are not less than [the upper limit value −60 μm]. The female screw reworking tool according to claim 1, wherein: The rectifying male screw is divided in a circumferential direction to form a plurality of lands, and a rake angle of a leading edge to be screwed into the female screw of the land is negative. Item 3. The internal thread repair tool according to Item 1 or 2. The rake angle of the peak portion at the leading edge is within a range of -20 ° to -60 °, the clearance angle of the leading edge is 0 °, and the diameter of the land is constant. 3. The internal thread repair tool according to 3. A plurality of corners form a regular polygonal column shape having an arc shape centered on an axis, and the arcuate corners function as the lands and the repair male screw is provided. The female screw reworking tool according to claim 3 or 4.

Images