JP4351710B2 - Screws with bit engagement holes and a group of bit engagement hole screws and driver bits - Google Patents

Description

  The present invention includes, for example, a bit engaging hole screw including a blade engaging groove with which a radial wing of a driver bit such as a cross hole engages, and a group of bit engaging hole screws of different sizes and the same. It relates to a combination with a driver bit used in the above.

As this type of conventional screw with a bit engagement hole, for example, a cross hole screw as disclosed in Patent Document 1 is known.
As shown in FIG. 9, the cross-recessed screw has a shaft portion 101 provided with a screw portion and a head portion 102 provided at one end of the shaft portion, and a tightening tool is provided on the head top surface 102a. A bit engaging hole 103 for engaging the bit 200 is provided. The bit engagement hole 103 includes a center hole portion 104 formed along the center axis N and a plurality of wing portion engagement grooves 105 extending radially from the center hole portion 104.

In the case of a cross hole, the groove end wall located at the radial end of the wing engaging groove 105 is inclined toward the bottom 106 of the center hole 104 in the direction approaching the central axis N, and the center of the wing 205 of the bit 200 is centered. However, when the tightening torque is increased, camout is likely to occur, and the shape of the bit engagement hole 103 is crushed.
Therefore, the cross-recessed screw described in Patent Document 1 includes an inclined portion 111 that inclines the groove end wall in a direction approaching the central axis N toward the bottom portion 106 of the central hole portion 104, and the inclined portion 111 and the step portion 112. And a parallel portion 113 that extends toward the top surface 102a of the head, and includes a slope portion 111 and a dedicated driver bit 200 having a wing portion 205 shaped to match the parallel portion 113. The tightening torque is increased and cam-out is prevented.

However, in the cross-recessed screw described in Patent Document 1, since the stepped portion 112 is a horizontal stepped portion that is orthogonal to the central axis N, when the bit engaging hole 103 is formed, the punch stepped portion is formed. There is a problem that the pressing reaction force concentrates on the portion corresponding to the portion 112 and the punch life is shortened. Furthermore, since the shape changes suddenly from the inclined portion 111 to the parallel portion 113 via the stepped portion 112, a portion where the fiber flow is buckled easily occurs. In particular, there was a tendency to buckle in the middle of the parallel part 113, and there was a problem of strength reduction.

In addition, if the length of the parallel portion 113 is increased, the tightening torque can be increased. However, if the length of the parallel portion 113 is increased, the fiber flow is likely to buckle and approaches the lower neck portion 102a. Therefore, there is a limit to lengthening the parallel portion 113 in terms of strength.
In addition, when the bit 200 is engaged with the bit engagement hole 103, there is a possibility that the tip of the bit is caught by the horizontal step portion 112 and cannot be engaged smoothly.
Further, since the parallel portion 113 is vertical (parallel to the central axis), there is a problem that the biting property of the driver bit is poor.
Japanese Patent No. 3863924

The present invention has been made in order to solve the above-described problems of the prior art, and an object of the present invention is to enable a bit to be smoothly engaged with an engagement groove and to achieve a punch life during molding. It is an object of the present invention to provide a screw with a bit engaging hole having a step portion having a shape that can greatly lengthen the length of the fiber flow and does not buckle the fiber flow.
Another object of the present invention is to provide a group of bit engagement hole screws that can be driven by a single driver bit with respect to a plurality of bit engagement holes of the bit engagement hole screws. It is to provide a combination with driver bits used in the above.

In order to achieve the above object, the invention according to claim 1 includes a shaft portion provided with a screw portion and a head portion provided at one end of the shaft portion, and the top surface of the head portion is provided. A bit engagement hole for engaging a driver bit is provided. The bit engagement hole includes a center hole formed along the center axis of the shaft and a plurality of blade portions extending radially from the center hole. A groove,
The wing engaging groove is connected via an inclined portion in which a groove end wall located at a radial end portion is inclined in a direction approaching the central axis toward the bottom of the central hole portion, and the inclined portion and the stepped portion. In a screw with a bit engagement hole configured to include a parallel portion extending toward the top surface of the head,
The stepped portion is an inclined stepped portion that is inclined in a direction in which the inner end on the side of the central axis is deeper than the outer end on the side opposite to the central axis with respect to an orthogonal line orthogonal to the central axis .
The inclination angle γ between the orthogonal line perpendicular to the central axis of the inclined step is set to 15 ° to 25 °,
The parallel portion is inclined at a predetermined inclination angle δ in the outward opening direction away from the central axis toward the top surface side of the head, and the inclination angle δ is set to 3 ° to 7 °,
An end of the parallel portion on the head top surface side is configured to be positioned on an extension line of the inclined portion .
In the invention according to claim 2 , the bit engagement hole is a cross hole provided with four wing portion engagement grooves, and the inclined portion is a standard conforming to the H-shaped cross hole defined in Japanese Industrial Standard JISB1012-1985. It is a shape.
According to the third aspect of the present invention, the parallel portion side portions of the mutually facing groove side walls of the wing portion engaging groove become a biting inclined surface that is inclined in a direction in which the interval gradually increases toward the top surface of the head. It is characterized by.

The invention according to claim 4 is a combination of a group of bit engaging hole screws of different sizes having the configuration according to claim 1 and a driver bit used for the screw group,
For the blade engagement groove of the bit engagement hole of each screw size, the shape of the inclined portion is the same for each screw size, and the depth from the top of the head at the bottom side of the inclined portion is the screw size. The depth of the parallel part is increased by making the intersection of the extension line of the inclined part and the top surface of the head the end of the parallel part on the top surface side of the head by increasing the depth of the parallel part. Set to increase step by step as the size increases,
The driver bit includes a base portion that is engaged with a central hole portion of the bit engagement hole, and a radial wing portion that engages with a wing portion engagement groove of the bit engagement hole. A blade inclined portion that engages a common inclined portion in a bit engaging hole of each screw size, and a blade of each screw size provided along an inclined extension line of the blade inclined portion and projecting outward from the inclined extension line There are multiple stages of blade parallel parts that engage the parallel part of the part engaging groove, and each blade parallel part has a greater depth than the parallel part of the bit engagement hole of one smaller screw size. It is the structure which protrudes in step shape corresponding to the area | region which carried out.

According to the fifth aspect of the present invention, the bit engagement hole is a cross hole having four wing engagement grooves, and the shape of the inclined portion of the wing engagement groove is defined in Japanese Industrial Standard JISB1012-1985. It is a standard shape conforming to the shape of the H-shaped cross hole.

According to the present invention, since the stepped portion is an inclined stepped portion, when the driver bit is engaged, the wing portion is guided by the inclined stepped portion and engaged with the inclined portion positioned at the back thereof.
Further, when the bit engaging hole is forged, the pressure reaction force acting on the punch portion for forming the inclined step portion is released in an oblique direction, so that the punch life can be greatly prolonged.
The fiber flow is also continuously connected from the parallel part to the inclined part through the inclined step part, and there is no part where the fiber flow is buckled in the middle part of the parallel part as in the prior art, so that chipping, cracking and the like can be prevented.
Furthermore, if the depth of the parallel portion is the same, the wing portion can have a larger engagement allowance than the conventional horizontal step portion by the amount of inclination of the inclined step portion. The tightening torque can be further increased when using a dedicated driver bit that engages with.

With respect to the inclination angle γ of the inclined step portion, the forming reaction force during forging was reduced by about 30% at 20 °, and a large change in stress was not observed at an angle larger than that. If the angle is increased too much, the length of the inclined portion cannot be secured, so it is preferable that the angle is about 15 ° to 25 °.
The biting property can be improved by inclining the parallel portion with respect to the central axis.
Further, if the inclination angle of the parallel portion is too large, the biting property is deteriorated, and therefore a range up to 5 ° is suitable.
Specially shaped to engage both the driver bit with the wing slope that engages the slope, the bit with the parallel wing that engages the parallel part, and both the slope and parallel part Driver bits can be used.
In particular, if the end portion on the top surface side of the parallel portion is positioned on the extended line of the inclined portion, it is compatible with a screw having a bit engaging hole only in the inclined portion, and the driver only in the inclined portion. The bit can be used as it is, and the inclined part of the wing part is guided to the end part of the parallel part to prevent rattling.

As described in claim 2 , by forming the inclined portion of the bit engagement hole as a standard shape portion conforming to the H-shaped cross hole defined in JISB1012-1985, a JIS-shaped bit can be used. A highly versatile screw with a bit engagement hole can be realized.
According to the third aspect of the present invention, the portions on the parallel portion side of the mutually facing groove side walls of the wing portion engaging groove are inclined in a direction in which the gap gradually increases toward the top surface of the head. Therefore, the biting property is improved not only on the end wall side of the parallel portion but also on the groove side wall, and the biting property can be further improved.

According to the fourth aspect of the present invention, even if the sinking depth of the bit engagement hole is increased, the wing portion parallel portion projecting stepwise is sequentially engaged with the parallel portion. For a specially shaped wing engaging groove having both of these, one driver bit can correspond to a plurality of sizes of bit engaging holes.
The wing portion parallel portion is engaged with the parallel portion of the wing portion engaging groove, so that the cam-out can be prevented, and the breaking torque is also increased by increasing the engagement margin.
Further, by engaging the parallel portion of the wing portion with the parallel portion of the engagement groove, it is possible to realize a combination of a bit engagement hole and a bit that is easy to bite against the screw and is easy to use.

According to the fifth aspect of the present invention, since the inclined portion of the bit engaging hole is a standard shape portion conforming to the H-shaped cross hole defined in JISB1012-1985, the wing engaging groove is formed as an inclined portion. JIS driver bits can be used as they are, although they have a special shape with parallel parts.

The present invention will be described below based on the illustrated embodiments.
FIG. 1 shows a screw with a bit engagement hole according to an embodiment of the present invention.
That is, the bit engagement hole screw 1 has a shaft portion 2 on which a screw is formed and a head portion 3 provided at one end of the shaft portion 2, and a bit of a tightening tool is provided on the head top surface 31. A bit engaging hole 4 to be engaged is provided. The bit engagement hole 4 is a cross hole, and includes a center hole portion 5 formed along the center axis N of the shaft portion 2 and a plurality of wing portion engagement grooves 6 extending radially from the center hole portion 5. Yes. The head shape is a pan head shape with a collar, but it can be applied to various shapes such as a pan shape without a collar, a dish shape, a round flat shape, a truss shape, and a binding shape.

  The blade engaging groove 6 includes an inclined portion 71 in which a groove end wall located at the radial end portion is inclined in a direction approaching the central axis N toward the hole bottom 51 of the central hole portion 5, and the inclined portion 71 and the inclined step portion. A parallel portion 73 extending toward the head top surface 31 via 72 is formed.

In the present embodiment, the inclined portion 71 of the blade engaging groove 6 has a shape conforming to the H-shaped cross hole defined in Japanese Industrial Standard JISB1012-1985, and the angle of the inclined portion 71 with respect to the central axis N As for A, the standard dimension is set to 26 ° 30 ′ and the tolerance is set to 0 to 25 ′ as per the standard.
The wing engaging groove 6 is open on the center hole 5 side and the head top surface 31 side, and the groove side walls 8 located on the left and right sides of the wing engaging groove 6 are engaged with the wing side surface of the bit. This is where the torque is transmitted. The center side opening edge 8a of the groove side wall 6 extends linearly, and the radial engagement width of the groove side wall 8 with which the wing portion of the bit engages gradually increases according to the inclination of the inclined portion 71, From the inclined stepped portion 72 to the parallel portion 73, the engagement width is expanded with respect to the extension line M of the inclined portion 71.

Moreover, the cross-sectional shape orthogonal to the central axis N of the center hole portion 5 is a substantially quadrangular shape in which the wing portion engaging groove 6 is positioned at the corner portion, and the adjacent wing portion engaging grooves 6 An engagement wall 9 having a predetermined width is provided therebetween. The engagement wall 9 is a bent surface that is slightly bent so that the central portion is convex toward the central axis. The engaging wall 9 is also an inclined surface inclined in a direction approaching the central axis N toward the bottom 51, and a trough between the wings of the bit is fitted. The left and right corners of the engagement wall 9 serve as the center side opening edge 8 a of the groove side wall 8.
Further, the bottom 51 of the central hole 5 is a conical surface inclined at a predetermined angle, and is continuous with the lower end of the blade engaging groove 6 and the lower end of the engaging wall 9. The inclination angle B of the conical surface of the bottom 51 is also set to an angle in accordance with JISB1012-1985. The reference dimension is 28 ° with respect to the orthogonal line orthogonal to the central axis N, and the tolerance is 0 to 1 °. Set to

On the other hand, the inclined step portion 72 has a predetermined angle γ in the direction in which the inner end on the side of the central axis is deeper than the outer end on the side opposite to the central axis N with respect to the orthogonal line H orthogonal to the central axis N. It has an inclined surface. The angle γ of the inclined stepped portion 72 is preferably set to about 15 ° to 25 ° in consideration of the tool life during forging.
The parallel portion 73 is configured to be inclined with respect to the central axis N by a predetermined angle δ in the outward opening direction toward the head top surface 31. The inclination angle δ of the parallel portion 73 is preferably set to 5 ° or less, preferably about 5 °. Further, in the illustrated example, the end portion 73a of the parallel portion 73 on the head top surface 31 side is located on the extension line M of the inclined surface portion 71, and between the end portions 73a of the parallel portion 73 at diagonal positions. The span is the wing length m. The position of the end portion 73a does not need to coincide with the extension line M, and may be located slightly outside the extension line M with respect to the extension line M.
A portion of the wing engaging groove 6 on the side of the parallel portion 73 of the groove sidewall 8 facing each other, in the illustrated example, a region extending in parallel with the central axis with the width of the inclined stepped portion 72 gradually toward the top surface 31 of the head. The biting inclined surface 81 is inclined in the direction in which the interval is increased. FIG. 1C shows the blade center line V in the direction of the blade center line V, which is perpendicular to the center axis N and bisects the blade engagement groove 6 in the width direction, as indicated by the arrow in FIG. FIG. 6 is a diagram projected onto an orthogonal plane orthogonal to the wing part center line V. In this projection view, the parallel portion 73 has a groove width n2 on the head top surface side that is larger than the groove width n1 on the inclined step portion 72 side, and the left and right sides 73c and 73c are perpendicular lines perpendicular to the head top surface. It is inclined by a predetermined angle ρ with respect to N1 (parallel to the central axis N).
The groove width of the groove side wall 8 on the JIS-shaped inclined portion 71 side is also inclined in a direction in which the interval gradually increases from the bottom side toward the head top surface 31 side. , 71c, the inclination angle ρ of the parallel 73 is larger than the inclination angle η with the vertical line N1.
In this embodiment, the inclination angle η of the inclined portion side portion of the groove side wall on the inclined portion 71 side is about 4 °, while the preferred range of the inclination angle ρ of the biting inclined surface 81 on the parallel portion 73 side. Is set to 9 ° ± 2 °, more preferably 9 °. In this way, the bit wings of the corresponding shape are bitten from the two directions of the outer surface side and the left and right side surfaces in combination with the inclination angle δ on the end wall side of the parallel portion 73. A cross hole with excellent adhesion can be realized.

  When the bit engagement hole 4 is forged, a tool having a cross-shaped punch blade portion 301 corresponding to the blade portion engagement groove 6 of the bit engagement hole 4 is used as shown in FIG. Then, the punch blade portion 301 is pushed into the workpiece, and the blade portion engaging groove 6 is formed following the shape of the punch blade portion 301. The punch blade portion 301 includes a punch blade portion inclined portion 302 for forming the inclined portion 71 of the blade engagement groove 6, a punch blade portion inclined step portion 303 for forming the inclined step portion 72, and a parallel portion 73. The punching blade parallel portion 304 for forming the punching blade, and the pressurizing reaction force acting on the punching blade inclined portion 303 from the workpiece during pressurization is released in an oblique direction, so that the punch life is significantly increased. can do.

As a result of the FEM analysis, the machining reaction force P ′ acting on the horizontal step portion 303 ′ as shown in FIG. 2C is 5799 [Mpa], while the inclined step portion 303 of the present invention is As a result, it was found that 4235 [Mpa] was reduced by 30% at an angle of 20 °.
In addition, there is no significant change in the stress of 4337 [Mpa] at 30 ° and 4331 [Mpa] at 40 °, and it is necessary to reduce the angle in order to ensure the length of the JIS-shaped inclined portion 71. For this reason, it is preferable that the angle is about 20 °.
As for the fiber flow after molding, as shown in FIG. 2 (B), the parallel portion 73 is continuously connected to the inclined portion 71 via the inclined step portion 72, and the horizontal step portion 172 shown in FIG. 2 (D). In the middle part of the parallel part 173, there is no defect 173a such as chipping or cracking due to the buckling b of the fiber flow.

As shown in FIG. 3, the cross-recessed screw according to the present embodiment includes a general-purpose bit 410 conforming to the JIS standard including an inclined wing portion 412 that engages with the inclined portion 71 and a parallel portion that engages with the parallel portion 73. Three types of driver bits are used: a straight bit 420 with a wing portion 421, a special shape bit with a wing portion parallel portion 23 that engages with a wing portion inclined portion 22 that engages with the inclined portion 71, and a parallel portion 73. Is possible.

As shown in FIG. 3 (A), the general-purpose bit 410 having the inclined wing part 412 is a standard shape defined in JIS 4633-1998, and includes four inclined wing parts 412 extending radially from the central base part 411. The outer surface 412a of the inclined wing part 412 is inclined in a direction approaching the central axis toward the tip.
The inclined wing portion 412 engages only with the inclined portion 71 of the wing portion engaging groove 6, but the end portion 73 a on the head top surface 31 side of the parallel portion 73 is located on the extension line of the inclined portion 71. The outer surface 412a of the inclined wing part 412 is guided to the end part 73a of the parallel part 73, and the bit does not rattle. Further, the engagement allowance between the blade portion engaging groove 6 and the inclined blade portion 412 is the same as that in the case of a cross hole of a normal JIS standard even if the parallel portion 73 is provided.

In the straight bit 420, the outer surface 421 a of the parallel wing portion 421 is parallel to the central axis N as shown in FIG. In this case, the parallel wing portion 421 of the bit 420 engages with the parallel portion 73 of the wing portion engaging groove 6 and comes into contact with the inner surface of the parallel portion 73 to transmit drive torque.
In this embodiment, since the parallel portion 73 is inclined by about 5 ° with respect to the central axis, the outer surface of the parallel wing portion 421 bites into the base side of the parallel portion 73, and the biting property can be improved. Further, in this embodiment, since the biting inclined surface 81 is provided in the parallel wall 73 side portion of the inner wall 8 of the engagement blade portion engaging groove 6, the inclination angle δ on the end wall side of the parallel portion 73 and As a result, it bites in from the two directions on the left and right side surfaces, so the biting property is remarkably improved.

  As shown in FIG. 3C, the special shape bit 20 has a configuration including four wing portions 22 extending radially from the central base portion 21, and the wing portion 22 is an inclined portion of the wing portion engaging groove 6. The wing portion inclined portion 23 engaged with 71, the wing portion inclined step portion 24 engaged with the inclined step portion 72, and the wing portion parallel portion 25 engaged with the parallel portion 73 are configured. The inclination angle of the wing portion inclined portion 23 is the same as the inclination angle A of the inclined portion 71 of the wing portion engaging groove 6. Also, the inclination angle of the wing portion inclination step portion 24 is set to the same angle as the inclination angle γ of the inclination step portion 24.

Further, the valley portion 26 between the inclined wing portion 22 and the inclined wing portion 22 is a portion engaged with the engagement wall 9 of the cross hole, and the diameter of the lower end of the valley portion 25 is the diameter of the lower end of the engagement wall of the cross hole. It is slightly larger than b and is configured to bite.
Further, the wing portion parallel portion 25 also has an outer surface that bites into the base side of the parallel portion 73 and has a good biting property, and the right and left side surfaces of the wing portion parallel portion 25 have a biting inclination of the inner wall 8. Since the surface 81 bites, an engagement structure excellent in biting can be realized.
If the length of the parallel portion 73 is the same as the inclination step portion 72 of the cross hole 4 is inclined, the engagement margin of the wing portion 22 is larger than the horizontal step portion, and the tightening torque is increased. can do.

Next, FIG. 4 shows a configuration example of a combination of a group of bit engaging hole screws of different sizes and a common driver bit used in the screw group.
In this example, the group of screw with a bit engagement hole is divided into a screw group of three sizes M3, M4, and M5 and a screw group of two sizes M6 and M8. Each screw group is different in the size of the reference inclined portion 71, specifically, the g dimension, which is the diameter of a circle passing through the bottom side end portion 71a.
The screw group of the first group will be described. As shown in FIG. 4 (F), the shape and dimensions of the inclined portion 72 of each of the blade engaging grooves of the bit engaging holes of M3, M4, and M5 are as follows. The screw size is the same.

The sinking depth q from the head top surface 31 at the end of the inclined portion 72 on the bottom side increases stepwise as the screw size increases. The extension line M of the inclined portion 72 and the top of the head By setting the intersection point with the surface 31 as the end portion 73a of the parallel portion 73 on the head top surface 31 side, the depth of the parallel portion 73 is set to increase stepwise as the screw size increases.
Since the inner end portion on the inclined portion 71 side of the inclined step portion 72 is determined at the upper end position of the inclined portion 71, the intersection of the extended line M of the inclined portion 71 and the head top surface 31 a is set to the top of the parallel portion 73. By using the end portion 73a on the surface 31 side, the shape dimensions of the inclined step portion 72 and the parallel portion 73 are automatically determined.

  On the other hand, as shown in FIG. 4A, the driver bit 520 is engaged with the base portion 521 engaged with the center hole portion 5 of the bit engagement hole 4 and the wing portion engagement groove 6 of the bit engagement hole 4. And radial wings 522 to be combined. The outer surface of the wing portion 522 is provided along the wing portion inclined portion 523 that engages the inclined portion 72 common to the bit engagement holes 4 of each screw size, and the extension line M of the wing portion inclined portion 523. A plurality of blade parallel portions 524 (M3), 524 (projecting outward from M and engaging the parallel portions 73 (M3), 72 (M4), 72 (M5) of the blade engaging grooves of each screw size ( M4) and 524 (M5) are provided. Each wing parallel part 524 (M3), 524 (M4), 524 (M5) has a stepped shape corresponding to a region where the depth of the parallel part is increased from the parallel part of the bit engagement hole of one smaller screw size. It is configured to overhang. The blade parallel portions 524 (M3), 524 (M4), and 524 (M5) and the blade inclined portion 523 are connected via a blade inclined step 525.

When this driver bit 520 is used for an M3 size screw, as shown in FIG. 4C, the wing portion inclined portion 523 of the driver bit 520 is engaged with the inclined portion 71 of the bit engaging hole 4. The first stage wing part parallel part 524 (M3) is engaged with the parallel part 73 (M3), and the cam-out torque is increased.
When used for an M4 size screw, as shown in FIG. 4 (D), the wing portion inclined portion 523 of the driver bit 520 engages with the inclined portion 71 of the bit engaging hole 4 and the wing portion inclined step. The portion 524 is partially engaged with the inclined step portion 72, and the second wing portion parallel portion 524 (M4) is partially engaged with the parallel portion 73 (M4). Although it does not engage with the parallel portion 73 (M4) as a whole, the wing portion parallel portion 524 (M4) having a large diameter is fitted to the parallel portion 73, which contributes to an increase in the cam-out torque and is bitten. Also good. Further, since the first stage and the second wing part parallel part 524 (M3), 524 (M3) are engaged with the groove side surface of the wing part engaging groove, the contact area is larger than that of the driver bit having only the inclined part. Thus, the driving torque can be increased.

When used for an M5 size screw, as shown in FIG. 4 (E), the blade portion inclined portion 523 of the driver bit 520 is engaged with the inclined portion 71 of the bit engaging hole 4, and the first stage, The three wing part parallel parts 531 532, and 533 of the second stage and the third stage engage with the parallel part 73 (M5). In this case as well, although it does not engage with the parallel portion 73 (M5) as a whole, the third-stage wing portion parallel portion 533 having a large diameter is fitted to the parallel portion 73 (M5), so that the cam-out torque is increased. Contributes and has good bite.
The wing portion inclined step portion 524 is partially engaged with the inclined step portion 72, and the third wing portion parallel portion 524 (M5) is partially engaged with the parallel portion 73 (M5). Although it does not engage with the parallel part 73 (M5) as a whole, the wing part parallel part 524 (M5) having a large diameter is fitted to the parallel part 73 (M5), which contributes to an increase in the camout torque. Good bite. In addition, since the first to third stage blade portion parallel portions 524 (M3), 524 (M4), and 524 (M5) are engaged with the groove side surface of the blade portion engaging groove, it is compared with a driver bit having only an inclined portion. As a result, the contact area increases and the driving torque can be increased.
In this way, if this specially shaped driver bit 520 is used, it is possible to deal with three sizes of screws with a single driver bit 520, although it is a specially shaped bit that engages both the parallel part 73 and the inclined part 71. be able to.

Next, a screw group having a size of M6 or more will be described.
In the size of M6 or more, as shown in FIG. 4 (J), the size of the inclined portion 71 ′ serving as a reference for the bit engagement hole 4 is increased by one step. The basic configuration is the same as that of a screw group having a size of M3 to M5 just by making the inclined portion 71 'one size larger.
That is, the shape dimension of the inclined portion 71 ′ constituting the bit engagement hole 4 of the screw is the same for the screws of the respective sizes of M6 and M8, and is parallel according to the sinking depth q of the bit engagement hole of each size. The parts 73 (M6) and 73 (M8) are enlarged step by step.

  As shown in FIGS. 4G and 4H, the bit 620 is formed in the base portion 621 engaged with the center hole portion 5 of the bit engagement hole 4 and the wing portion engagement groove 6 of the bit engagement hole 4. And a radially inclined wing portion 622 to be engaged. On the outer surface of the inclined wing portion 622, a wing portion inclined portion 622 that engages with an inclined portion 71 'common to the bit engaging holes 4 of the M6 and M8 bit engaging hole screws, and this wing portion A two-stage wing portion parallel portion 624 that protrudes from the extension line M along the extension line M of the inclined portion 622 and engages with the parallel portions 73 (M6) and 73 (M8) of the bit engagement hole 4 of each size screw. (M6) and 624 (M8) are provided. The blade parallel parts 624 (M6) and 624 (M8) are configured to project in a stepped manner corresponding to the region where the depth of the parallel part of the bit engaging hole of the screw of one small size is increased. Then, the second wing portion parallel portion 624 (M8) corresponds to a region in which the depth of the parallel portion 73 (M8) is larger than the parallel portion 73 (M6) of the bit engaging hole of one smaller M6 size. It is configured to project in a staircase shape.

FIG. 4I shows a case where the screw is used for an M8 size screw.
When used for an M8 size screw, the blade portion inclined portion 622 of the driver bit 620 engages with the inclined portion 71 of the bit engaging hole 4, and the second-stage blade portion parallel portion 624 (M8) is parallel. Engage with the portion 73 (M8). In this case as well, the second stage parallel part 73 (M8) is not engaged entirely, but the large-diameter wing part parallel part 632 is fitted to the parallel part 73 (M8), which increases the cam-out torque. Contributes and has good bite. Further, since the first and second stage blade parallel portions 624 (M6) and 624 (M8) engage with the groove side surface of the blade engaging groove, the contact area is larger than that of the driver bit having only the inclined portion. Thus, the driving torque can be increased.

Next, a method for setting the shape and size of the bit engagement hole of each screw group will be described.
1) Depth setting of the parallel part 73-Cam-out torque change due to the difference in the length of the parallel part The depth dimension r of the parallel part 73 is the point at which the change of the cam-out torque disappears from the relationship between the depth of the parallel part 73 and the cam-out torque. The depth dimension of the parallel part 73 is determined based on the depth.
FIG. 5 shows changes in the camout torque To of the cross holes of the sizes M3, M4, and M5 due to the difference in the length of the parallel portion 73. FIG. For each size, the camout torques To (3), To (4), and To (5) no longer change from a certain depth. The parallel part depth r at the time when this change disappears is determined as parallel part depths r3, r4, r5 of each size.
In this example, r3 was 0.70 mm, r4 was 1.23 mm, and r5 was 1.84 mm.
Further, the camout torques To (3), To (4), and To (5) at this time are more than three times the tightening torques T1 (3), T1 (4), and T1 (5). No come-out will occur.

2) Comparison of camout torque in JIS-shaped inclined portion 71 When the sink depth q is 1.5 mm or more in the M3 size, the camout torque of the specially shaped cross hole having the inclined portion and the parallel portion of the present invention is The height is higher than the cross hole of only the inclined portion of the JIS standard, and by providing the parallel portion 73 rather than increasing the contact area with the driver bit, the effect of the floating countermeasure is obtained.

3) Sink depth q dimension In the M3 size, the sink depth q is required to be 1.5 mm or more from the camout torque, and the q depth is set so that it can also be used for the JIS head shape.
When the q depth is set, a cross-sectional ratio with the neck R as shown in FIG.
The cross-sectional ratio is S, where S is the distance between the bottom end 71a of the inclined portion 71 and the neck R, which is the base of the lower surface of the head 3 and the shaft 2, and D is the header blank diameter. The minimum cross-sectional ratio is required to be 20% or more. In order to apply to all of the head shapes defined in JIS, it is necessary to make the dimensions satisfying a “dish head” having a minimum head height of 1.75 mm.
Therefore, the q depth was set to 1.54 mm, the g dimension was changed from 2.286 [mm] defined in JIS to 2.09 [mm], and the distance S from the neck R was adjusted.
As a result, even in the case of a countersunk head, the minimum cross-sectional ratio is 0.513 / 2.60, which is 20%, and there is no risk of head skipping. In addition, when the q depth is 1.54 [mm], the blade dimension m is 3.59 [mm], and the m dimension of the pan, dish, round dish, and bind defined by JIS is 3.60. It is in a range of ˜3.80, and any head shape can be handled.

4) Setting the angle of the inclined step portion The angle of the inclined step portion 72 is set to 20 °. As shown in FIG. 6A, when the depth r of the parallel portion 73 is 1 mm, the q depth is 1 Since it becomes deeper than .54 mm, the depth of the parallel portion is set to 0.7 mm.
5) Other size settings ・ M4, M5
The q depth of each size is calculated from the following calculation formula.
q [mm] = 0.05x ² + 0.27x + 0.28
Here, x is a screw size.
In this calculation formula, the inclined portion 71 is made the same as the dimensional shape of the reference M3-sized inclined portion 71, and the end portion on the head top surface side of the parallel portion 73 having the depths r4 and r5 obtained in 1) above. The relational expression between the screw size and the q depth is obtained by using the screw size as a parameter so that the position 73a is located on the extension line M of the inclined portion 71.
FIG. 7A is a graph with the screw size x on the horizontal axis and the q depth on the vertical axis. The relational expression was obtained from this graph.
The line of q depth calculated from this relational expression is the top surface of the head, and as shown in FIG. 6B, intersections C3, C4, C5 of the extension line M of the inclined portion 71 are obtained, and the intersections C3, C4, A straight line of 5 ° from C5 is extended downward, and intersections D3, D4, and D5 with a straight line L extended from the upper end of the inclined portion 71 at an angle γ (20 ° in this example) with respect to the horizontal line Let it be a corner of the parallel part 73.
These M3, M4, and M5 size cross holes are JIS H-type cross hole Nos. Corresponds to 2.

・ M6, M8
These M6 and M8 size cross holes are JIS H-type cross hole Nos. 3 and the dimensional shape of the inclined portions 71 of M6 and M8 sizes is the same. Since the shape of the cross hole becomes large, the g dimension of the lower end of the inclined portion 71 is changed from 3.81 [mm] defined in JIS to 3.48 [mm] at the same ratio as No2.
Next, q depth [mm] of each size is calculated from the following calculation formula.
q [mm] = 0.75x-1.42

No. 3, the ratio of the inclined portion 71 to the parallel portion 73 is No. 3. The dimensions of the inclined portion 71 and the parallel portion 73 are calculated so as to have the same ratio as the minimum size M3 of 2. The ratio is 1.178. If the length dimension of the parallel part 73 is multiplied by 1.178, the intersection of the inclined part 71 and the inclined step part 72 is obtained.
The inclination angle γ of the inclined step portion 72 is set to 20 °.
No. 2, no. In each of the three driver bits, the inclined step portion 72 starts from the upper end of the inclined portion 71 and has a shape that can be tightened even in the JIS bit. Driver bit does not enter when inside.
In this way, since the size of the inclined portion 71 is constant, the ratio of the parallel portion depth to the q depth increases stepwise, but the proportion is as shown in FIG. 7B. , No. No. 2 for the first group of screw cross holes using two driver bits. In the cross hole of the second group of screws using 3 driver bits, it is 45-59%.

FIG. 8 shows a reference example of a combination of a group of bit engagement hole screws of different sizes and a bit for a tightening tool used in the screw group.
The configuration of the screw group is the same as that of the above combination configuration example, and only the configuration of the driver bit is different. In the following description, only the configuration of the driver bit will be described, and the configuration of the screw with the bit engagement hole will be denoted by the same reference numeral as in the above-described combination configuration example, and description thereof will be omitted.
The driver bit 720 includes a base 721 that engages with the central hole 5 of the bit engagement hole 4 and a radial wing 722 that engages with the wing engagement groove 6 of the bit engagement hole 4. The outer surface of the wing 722 is engaged with the inclined portion 71 common to the bit engagement holes 4 of each screw size and at the head of the parallel portion 73 of the bit engagement hole 71 of at least the maximum size M5 screw. An inclined portion 722a extending to the position of the end portion 73a on the top surface side and a straight portion 722b following the inclined portion 722a are provided.

On the outer surface of the wing portion 722, there are three steps facing the vicinity of the head top surface side end portion 73a of the parallel portion 73 of the wing portion engaging groove 6 of each of the M3, M4, and M5 screw sizes via a predetermined gap. Wing parallel portions 734 (M3), 734 (M4), and 734 (M5) are provided.
In the case of this embodiment, the blade parallel portions 734 (M3) and 734 (M4) corresponding to the M3 and M4 sizes are formed by partially cutting the inclined outer surface 722a, and correspond to the maximum M5 size. As for the wing portion parallel portion 734 (M5), the wing portion parallel portion 734 (M5) is configured by the end portion on the inclined portion side of the straight portion 722b of the wing portion.
When this driver bit 720 is used for an M3 size screw, as shown in FIG. 8C, the inclined portion 722a of the driver bit 720 is engaged with the inclined portion 71, and the first-stage wing portion parallel portion is engaged. 734 (M3) engages with the parallel part 73 (M3) with a small gap therebetween. Although there is a slight gap, the cam-out torque can be increased and the biting property is also improved.
Although a minute gap is formed between the parallel part 73 and the wing part parallel part 734, the biting property on the outer surface side of the parallel part 73 is slightly lowered, but it is parallel to the inner wall 8 of the wing part engagement groove 6. Since the biting inclined surface 81 is provided corresponding to the portion 73, the biting property is not impaired.
When used for an M4 size screw, as shown in FIG. 8D, the inclined portion 722a of the driver bit 720 engages with the inclined portion 71, and the second stage wing portion parallel portion 534 (M4). Engage with the parallel part 73 (M4) with a small gap. Even in this case, although there is a slight gap, the cam-out torque can be increased and the biting property is also improved.

When used for an M5 size screw, as shown in FIG. 8E, the inclined portion 722a of the driver bit 720 engages with the inclined portion 71, and the third stage wing portion parallel portion 734 (M5). Engages the parallel part 73 (M5) through a minute gap. Also in this case, although it does not engage with the parallel part 73 (M5) as a whole, it contributes to an increase in the cam-out torque and also improves the biting property.
In this example, M3 to M5 size No. Although the case where the present invention is applied to a driver bit having a size of 2 has been described, No. 2 applied to M6 and M8. The same applies to the third driver bit. Further, the specially shaped driver bit 720 can be used not only for the screw group but also for a general-purpose cross hole defined by the JIS standard, and is highly versatile.
Further, in this reference example , it is not necessary to position the end portion of the parallel portion 73 on the head top surface 31 side on the extension line M of the inclined portion 72, and the blade portion parallel portion 734 is slightly inward from the extension line M. You may make the clearance gap between and small. If it does in this way, biting property can be improved more.

In each of the above-described embodiments, the radial wing portion engaging groove with which the wing portion engages as the bit engaging hole is described as an example of four cross holes. However, the embodiment is not limited to the cross hole, and for example, a radial shape. The wing portion engaging groove may have three or five or more.
In addition, regarding the shape of the wing portion engaging groove of the cross hole, the portion below the inclined step portion is a standard shape portion conforming to the JIS standard. However, the shape may not be a shape conforming to the JIS standard. It is only necessary that the end wall portion of the groove has a shape having an inclined surface portion and a parallel portion, and the inclined surface portion and the parallel portion are connected by an inclined step portion.

FIG. 1 shows a screw with a bit engaging hole according to an embodiment of the present invention. FIG. 1 (A) is a longitudinal sectional view showing a hole-shaped portion, and FIG. 1 (B) is a plan view of the bit engaging hole. (C) is a view in the direction of arrow C in FIG. (B). 2A is a partial perspective view of a punch blade portion forming a cross hole in which the step portion of FIG. 1 is inclined, and FIG. 2B is a schematic view of a fiber flow state in the vicinity of the punch blade portion of FIG. FIG. 2 (C) is a partial perspective view of a punch blade portion forming a conventional cross hole with a horizontal step portion, and FIG. 2 (D) is a fiber flow state in the vicinity of the punch blade portion of FIG. 2 (C). FIG. FIG. 3 shows various bits used for tightening the screw with the bit engagement hole of FIG. 1, and FIG. 3 (A) is a schematic diagram in the case of using a general-purpose bit having an inclined wing portion, FIG. 3 (B). Is a schematic diagram in the case of using a bit provided with a parallel wing portion, and FIG. 8C is a schematic diagram in the case of using a dedicated bit provided with an inclined wing portion with a protruding portion. FIG. 4 shows an embodiment of a combination of a group of cross-recessed screws of different sizes and a bit for a tightening tool used in the screw group. FIG. 4A shows a first group of screws M3 to M5. The front view which shows the structure of the bit used for this, The figure (B) is a bottom view of a bit, The figure (C) thru | or (F) are the figures which show the engagement state of the screw and bit of M3 thru | or M5 size, The figure (F) is explanatory drawing which shows the dimensional relationship of the cross hole of the screw group of M3 thru | or M5, The same figure (G) is a front view which shows the structure of the bit used for the screw of the 2nd group of M6 and M8 size, FIG. (H) is a bottom view of FIG. (G), FIG. (I) is a view showing an engagement state of an M8 size screw and a bit, and FIG. (J) is a cross hole dimension of the M6 to M8 screw group. It is explanatory drawing which shows a relationship. FIG. 5A is a graph showing the relationship between the parallel portion depth of the cross hole provided in the first group of screws in FIG. 4 and the cam-out torque, and FIG. 5B is a graph showing the relationship between the q depth and the cam-out torque. . 6A is a diagram showing the relationship between the depth of the parallel portion and the inclination angle of the inclined step portion, and FIG. 6B is a diagram showing a drawing example of the parallel portion. 7A is a graph showing the relationship between the q depth and the recess depth according to the screw size of each screw group shown in FIGS. 4 and 5, and FIG. 7B is a graph showing the relationship between the q depth and the recess depth. It is a graph which shows the ratio of the parallel part depth with respect to q depth in the screw size of a screw group. FIG. 8 shows a reference example of a combination of a group of cross-recessed screws having different sizes and a bit for a tightening tool used in the screw group. FIG. 8A is a front view showing the configuration of the bit. (B) is a bottom view of the bit, and (C) to (E) are views showing engagement states of M3 to M5 size screws and the bit. FIG. 9 shows a conventional cross-recessed screw. FIG. 9A is a sectional view showing a combination of the hole shape and the bit, and FIG. 9B is a plan view of the screw head.

DESCRIPTION OF SYMBOLS 1 Screw with bit engagement hole 2 Shaft part 3 Head, 31 Top face 4 Bit engagement hole 5 Center hole part, 51 Bottom part 6 Wing part engagement groove 7 Groove end wall 71 Inclination part, 71 'Inclination part 72 Inclination Stepped portion 73 Parallel portion 72 (M3), 72 (M4), 72 (M5) Parallel portion 72 (M6), 72 (M8) Parallel portion 8 Groove side wall, 81 Biting inclined surface 9 Engagement wall A of inclined portion 71 Angle M with respect to the central axis N Extension line N of the inclined portion 71 Central axis γ Inclined angle δ of the inclined step portion 74 Inclined angle 20 of the parallel portion 73 Bit 21 Base portion 22 Wing portion 23 Wing portion inclined portion 24 Wing portion inclined step portion 25 Wings Part parallel part N1 Center line 300 Punch 301 Punch blade part 302 Punch blade part inclined part 303 Punch blade part inclined step part 304 Punch blade part parallel part 410 General-purpose bit 411 Base part 412 Blade part
412a Outer surface 420 of wing part Parallel bit 421 Parallel wing part, 421a Outer side surface 520 Bit 521 Base 522 Wing part 523 Wing part inclined part 524 (M3), 524 (M4), 524 (M5) Wing part parallel part 525 Wing part Inclined step portion 620 Bit 621 Base portion 622 Wing portion 623 Wing portion inclined portion 624 (M6), 624 (M8) Wing portion parallel portion 625 Wing portion inclined step portion 720 Bit 721 Base portion 722 Wing portion 722a Inclining portion 722b Straight portion 734 (M3) ), 734 (M4), 734 (M5) Wing parallel part

Claims (5)

The shaft has a threaded portion and a head portion provided at one end of the shaft portion, and a bit engaging hole for engaging a driver bit is provided on the top surface of the head portion. The hole includes a central hole portion formed along the central axis of the shaft portion, and a plurality of wing portion engaging grooves extending radially from the central hole portion, the wing portion engaging grooves having radial ends. A groove end wall that is located on the bottom portion of the center hole portion and inclines in a direction approaching the central axis toward the bottom of the central hole portion, and a parallel portion that is connected to the inclined portion via the step portion and extends toward the top surface of the head portion. In a screw with a bit engagement hole having a configuration comprising:
The stepped portion is an inclined stepped portion that is inclined in a direction in which the inner end on the side of the central axis is deeper than the outer end on the side opposite to the central axis with respect to an orthogonal line orthogonal to the central axis .
The inclination angle γ between the orthogonal line perpendicular to the central axis of the inclined step is set to 15 ° to 25 °,
The parallel portion is inclined at a predetermined inclination angle δ in the outward opening direction away from the central axis toward the top surface side of the head, and the inclination angle δ is set to 3 ° to 7 °,
A screw with a bit engagement hole, characterized in that an end of the parallel part on the top side of the head is positioned on an extension line of the inclined part . Bit engaging hole is a cross recess with four wings engaging groove, according to claim 1 inclined portion is a standard shape that conforms to the H-shaped cross recess defined in Japanese Industrial Standard JISB1012-1985 Screw with bit engagement hole. The bit engagement hole according to claim 1 or 2 , wherein a portion of the blade side wall of the wing portion engagement groove on the parallel portion side is a biting inclined surface inclined in a direction gradually expanding toward the top surface of the head. With screw. A combination of a group of bit engagement hole screws of different sizes having the configuration according to claim 1 and a driver bit used in the screw group,
For the blade engagement groove of the bit engagement hole of each screw size, the shape of the inclined portion is the same for each screw size, and the depth from the top of the head at the bottom side of the inclined portion is the screw size. The depth of the parallel part is increased by making the intersection of the extension line of the inclined part and the top surface of the head the end of the parallel part on the top surface side of the head by increasing the depth of the parallel part. Set to increase step by step as the size increases,
The driver bit includes a base portion that is engaged with a central hole portion of the bit engagement hole, and a radial wing portion that engages with a wing portion engagement groove of the bit engagement hole. A blade inclined portion that engages a common inclined portion in a bit engaging hole of each screw size, and a blade of each screw size provided along an inclined extension line of the blade inclined portion and projecting outward from the inclined extension line There are multiple stages of blade parallel parts that engage the parallel part of the part engaging groove, and each blade parallel part has a greater depth than the parallel part of the bit engagement hole of one smaller screw size. A combination of a screw with a group of bit engaging holes and a driver bit, wherein the screw is configured to project in a stepped manner corresponding to the region. The bit engagement hole is a cross hole provided with four wing part engagement grooves, and the shape of the inclined part of the wing part engagement groove conforms to the shape of the H-shaped cross hole defined in Japanese Industrial Standard JIS B1012-1985. The combination of a group of bit engaging hole screws and a driver bit according to claim 4 , which is a standard shape.

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