JP2016017548A - Coming-off prevention washer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coming-off prevention washer capable of dispensing with a deformable material, and not needing a large accommodation space with a simple constitution.SOLUTION: An inner peripheral face of a through hole 12 of a washer 10 is composed of a non-female screw portion on which a female screw is not formed. The non-female screw portion has a small-diameter portion 16 fitted between thread portions of a male screw portion of a screw member for preventing linear movement in a center line direction of the through hole 12 to the thread portion, and a large-diameter portion 14 permitting movement in a twisting direction over the thread portion of the male screw portion, of the screw member in being twisted around a center line O of the through hole 12, and having a diameter larger than the small-diameter portion 16.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a retaining washer.

Conventionally, as a retaining washer, the washer of Patent Literature 1, Patent Literature 2, and Patent Literature 3 has been proposed.
The retaining washer disclosed in Patent Document 1 is a thin metal plate having a first surface and a second surface opposite to the first surface, and a circular shaft penetrating from the first surface to the second surface. A hole (through hole) is formed. The shaft hole has a plurality of slits directed radially outward. A circular terminal hole is formed at the end located on the radially outer side of the slit.

  An inclined portion is formed in the vicinity of the shaft hole so as to be inclined from the first surface to the second surface. The diameter of the shaft hole is smaller than the head of the screw, and is smaller than the outer diameter formed by the thread portion of the shaft portion of the screw and the inner diameter formed by the screw valley portion. In the retaining washer, a flexible region having a substantially fan-like spring property is defined by a virtual line connecting the slit and the adjacent terminal hole.

  For this reason, when a retaining washer is inserted from the first surface toward the second surface with respect to the shaft portion of the screw, the flexible region is bent and deformed toward the second surface. The retaining washer inserted into the shaft portion is difficult to come off because a shaft hole is caught in the thread portion of the screw in the direction in which the screw is removed from the shaft portion.

In the retaining washer of Patent Document 2, the washer body includes a screw insertion hole that fits into the shaft portion of the screw and a protrusion that protrudes in the tip direction of the screw.
The washer of Patent Literature 3 includes a plurality of claw portions protruding toward the inside in the radial direction of the hole portion around the hole portion through which the male screw portion of the male screw member is inserted, and the tip portion of the claw portion is the aforementioned portion. It engages with the thread of the male thread.

JP 2013-19433 A JP 2001-50236 A Japanese Patent Laid-Open No. 5-180211

  In Patent Document 1, since the inclined portion has a shape that rises inclined from the second surface, the structure is complicated, and it is necessary to take up a storage space corresponding to the protruding portion as compared with a flat plate washer. is there.

The retaining washer disclosed in Patent Document 2 has a configuration in which the screw shaft portion is simply fitted into the screw insertion hole, so that the washer is likely to come off from the screw shaft portion.
The washer of Patent Document 3 is actually configured such that the connecting portion of the claw portion with the washer body is bent so that the tip portion protrudes on one surface of the washer body. And it is necessary to incline the said front-end | tip part with respect to a washer main body by the angle corresponding to the pitch angle of the thread of the said external thread part. Therefore, in Patent Document 3, in order to make the angle at the nail part, it is necessary to plastically deform the nail part, or it is necessary to form the nail part to have an angle in advance, which raises the manufacturing cost. In addition, there is a premise that a metal that can deform the claw portion of the washer body is used.

  An object of the present invention is to provide a retaining washer that does not require a deformable material and has a simple configuration and does not require a large storage space.

  The retaining washer according to the present invention is a retaining washer that is formed in a ring shape having a through hole, and is inserted and attached to a screw member having a male screw portion. The surface is a non-female screw part in which a female screw is not formed, and the non-female screw part is inserted between the screw thread parts of the male screw part, and the through-hole is inserted into the screw thread part. A small-diameter portion that prevents linear movement in the center line direction, and when twisted around the center line of the through hole, allows movement in the torsion direction beyond the thread portion of the male screw portion, and It has a large diameter part larger than the small diameter part.

Moreover, the said large diameter part is formed within less than 180 degrees among the whole internal peripheral surfaces of the said through-hole.
Further, when the diameter of the small diameter portion is A, the diameter of the small diameter portion is in a range of Amin ≦ A <Amax.

  In addition,

It is.

  According to the present invention, there is an effect that a deformable material is not required and a simple configuration is not required to take a large storage space.

The perspective view of the washer of a 1st embodiment. (A) is a fragmentary top view of the washer of 1st Embodiment, (b) is principal part sectional drawing for showing the positional relationship at the time of inserting a male screw in a washer. Schematic explanatory drawing which shows the usage example of the washer of 1st Embodiment. Explanatory drawing at the time of letting a male screw pass in the screw insertion hole of a washer in 1st Embodiment. Explanatory drawing of a calculation formula. Explanatory drawing of a calculation formula. Explanatory drawing of a calculation formula. The perspective view of the washer of 2nd Embodiment. (A) is a partially omitted plan view of the washer of the second embodiment, (b) is a cross-sectional view when screwing the washer into the male screw portion 22 of the screw member. The top view of the retaining washer of other embodiment.

(First embodiment)
Hereinafter, a retaining washer according to a first embodiment embodying the present invention will be described with reference to FIGS.

  As shown in FIG. 1, a retaining washer 10 (hereinafter simply referred to as a washer) is a plain washer having a through hole 12 and formed in a ring shape. The washer 10 of this embodiment is made of metal such as stainless steel, but may be made of synthetic resin. When the washer 10 is made of metal, it is formed by press punching or laser processing.

  The through hole 12 is penetrated from the front surface 10 a to the back surface 10 b of the washer 10. The thickness t of the washer 10 is shorter than the pitch p of the thread of the male screw that uses the washer 10.

  The inner peripheral surface of the through hole 12 is a non-female screw portion in which a female screw is not formed. The through hole 12 has a large diameter portion 14 having a radius R passing through the center line O of the through hole 12 and a small diameter portion 16 having a diameter A passing through the center line O. Further, in the washer 10, the peripheral edge portion of the through hole 12 having the small diameter portion 16 has rigidity and is not deformed when being attached to the screw member 20.

  As shown in FIG. 1, the inner peripheral surface of the large-diameter portion 14 is a pair of inner surfaces 14a and 14b having an arc shape. The centers of curvature of the inner surfaces 14a and 14b are aligned with the center line O. On the other hand, the inner peripheral surface of the small-diameter portion 16 is a pair of inner surfaces 16a and 16b that are parallel to each other and form a linear shape.

  The large-diameter portion 14 is preferably less than half of the entire inner peripheral surface of the through-hole 12 (when it is the center of the through-hole). If the large-diameter portion 14 is half or more of the entire inner peripheral surface of the through-hole 12, it is easy to drop off when inserted into the male screw portion 22 of the screw member 20 described later.

  When the washer 10 shown in FIG. 2A is attached to the screw member 20 and is twisted around the center line O of the through hole 12, the radius R of the large diameter portion 14 is the screw of the male screw portion 22 of the screw member 20. The length is allowed to move in the torsional direction beyond the peak portion 22a. Further, the radius R of the large diameter portion 14 has a length equal to or greater than the upper limit value Amax of the small diameter portion 16 described later.

Further, the diameter A of the small-diameter portion 16 is set to a size that can be engaged between the screw thread portions 22 a of the male screw portion 22.
The diameter A of the small diameter portion 16 is set to Amin ≦ A <Amax.

  The lower limit value Amin and the upper limit value Amax are calculated by the following equations.

In addition,

It is.

  The apex of the thread portion 22a of the actual screw member 20 has a trapezoidal cross section, and the diameter of the apex of the cross sectional shape is referred to as a screw diameter (diameter). On the other hand, the apex diameter D of the screw is a diameter when the apex is an intersection Q obtained by extending the slope of the screw thread portion 22a.

(About the lower limit Amin)
Formula (1) is a calculation formula for the lower limit value Amin of the diameter A of the small diameter portion 16. The lower limit value Amin is a case where the ridge line with the front surface 10a and the ridge line with the back surface 10b are respectively in contact with the thread slope between the thread portions 22a of the screw member 20 at the portions of the inner surfaces 16a and 16b of the washer 10. It is assumed.

  FIG. 5 is an explanatory diagram for deriving equation (1) when the washer 10 is in the state of FIG. In FIG. 2A, the washer 10 is inclined with respect to the axis O1 of the screw member 20. On the other hand, for convenience of explanation, in FIG. 5, unlike FIG. 2A, the washer 10 is not tilted, and the center line O of the through hole 12 is aligned with the axis O <b> 1 of the screw member 20. This is shown in the figure. Therefore, in FIG. 5, the inner surfaces 16a and 16b are not shown in a state of being inclined with respect to the axis O1, unlike FIG.

  In FIG. 5, point E is a point on the inner surface 16a, and is a point that is t / 2 separated from the surface 10a in the thickness direction. Point F is a point that is t / 2 separated from the surface 10a on the inner surface 16b that is separated from the point E by a diameter A (that is, Amin). Point G is a point forming a right triangle having a straight line EF as a hypotenuse. The point G is located at a position separated from the point F by 1/2 of the thread pitch p.

  Actually, the center line O of the washer 10 does not coincide with the axial center O1, and the respective ridgelines abut against the thread slope between the thread portions 22a as shown in FIG. Although it differs from what was done, since Formula (1) deals only with length, there is no problem.

  From the above, equation (4) is established.

Equation (1) is derived from Equation (4).

X is calculated as follows.
FIG. 6 is an enlarged view of the periphery of one inner surface 16b on the premise that the ridgelines of the inner surfaces 16a and 16b of the washer 10 are in contact with the slopes of the thread portions, respectively. As shown in the figure, the vertical line L extending from the valley portion opposite to the screw thread portion 22a passes through ½ of the thickness t of the washer 10 and ½ of the pitch p. For this reason, the following relational expression is established.

As shown in FIG. 6, α is the distance from the valley to the inner surface 16b (or the inner surface 16a), and β is the distance from the intersection of the valley to the straight line M connecting the pair of intersections Q. .

  From Expression (5), Expression (6) and Expression (7) are obtained.

here,

It is.

Expression (3) is derived from Expression (6), Expression (7), and Expression (8).
(About upper limit Amax)
Formula (2) is a formula for calculating the upper limit value Amax of the diameter A of the small diameter portion 16.

  As shown in FIG. 2B, one of the portions having the inner surfaces 16a and 16b of the small-diameter portion 16 is engaged with the slope of the screw thread portion 22a, and the other is trapezoidal. A limit size not exceeding the thread portion 22a is assumed.

  First, in FIG. 7, one of the portions having the inner surfaces 16a and 16b of the small diameter portion 16 of the washer 10 is engaged with the inclined surface of the screw thread portion 22a, and the other extends the inclined surface of the screw thread portion 22a. Assume a state in contact with the intersection point Q obtained in the above. The lower limit value A0max in this case is calculated by the following equation (9).

Expression (9) is derived from the following expression (10).

By the way, actually, as shown in FIG. 2 (b), either one of the portions having the inner surfaces 16a, 16b of the small diameter portion 16 is engaged with the inclined surface of the screw thread portion 22a, and the other is A limit size not exceeding the trapezoidal thread portion 22a is assumed. For this reason, in order to calculate the upper limit value Amax, as shown in FIG. 7, it is necessary to subtract ½ (D−d) from A0max. Therefore, the equation (2) is derived from the following equation (11). Is done.

(Operation of the embodiment)
Now, the operation of the washer 10 configured as described above will be described with reference to FIGS. As shown in FIG. 3, the washer 10 is twisted around the axis O <b> 1 from the tip of the male screw portion 22 of the screw member 20. And it arrange | positions to the neck part 26 between the external thread part 22 and the head 24 which are further shown with the dashed-two dotted line from the continuous line shown in FIG. The neck portion 26 is not provided with the screw thread portion 22a, and the small diameter portion 16 is formed to be movable along the direction of the axis O1.

  When the washer 10 is screwed into the male screw portion 22, the small diameter portion 16 shown in FIG. 1 enters between the screw thread portions 22a of the male screw portion 22, and the large diameter portion 14 exceeds the screw thread portion 22a. Go. For this reason, the washer 10 moves along the axis O1 of the screw member 20 to the neck portion 26 while rotating around the axis O1. By moving the washer 10 to the neck part 26, it can be set as a washer built-in screw. In this case, if a spring washer 45 is passed through the neck portion 26 in advance as shown in FIG.

  When the washer 10 is removed from the screw member 20 after the washer 10 has moved to the neck portion 26, it is necessary to reverse the washer 10 and move it on the male screw portion 22. 10 and the spring washer 45 between the washer 10 and the head 24 do not fall off the screw member 20.

  In this state, for example, the screw member 20 incorporating the washer 10 shown in FIG. 3 is inserted into the through holes 32 and 42 respectively provided in the pair of plate members 30 and 40, and then the nut 50 is screwed into the male screw portion 22. By joining, the plate materials 30 and 40 can be fastened. Later, when the screw member 20 is removed, the washer 10 stays at the position of the neck portion 26, so that the washer 10 and the spring washer 45 do not fall off the screw member 20.

(Example)
Table 1 shows the lower limit value Amin of the small-diameter portion 16 in the washer used for each screw member 20 of M5 × 0.8, M6 × 1, M8 × 1.25, and M10 × 1.5 which are metric screws. And the upper limit value Amax is calculated.

As shown in Table 1, in the screw member 20 of M5 × 0.8, when the thickness t of the washer 10 is 0.400 mm, the lower limit value Amin of the diameter A of the small diameter portion 16 is 4.498 mm, and the upper limit value Amax. May be 4.740 mm.

  Further, in the M6 × 1 screw member 20, when the thickness t of the washer 10 is 0.500 mm, the lower limit value Amin of the diameter A of the small diameter portion 16 is 5.374 mm, and the upper limit value Amax is 5.675 mm. Good.

  Further, in the M8 × 1.25 screw member 20, when the thickness t of the washer 10 is 0.6600 mm, the lower limit value Amin of the diameter A of the small diameter portion 16 is 7.172 mm, and the upper limit value Amax is 7.572 mm. do it.

  Further, in the M10 × 1.5 screw member 20, when the thickness t of the washer 10 is 0.800 mm, the lower limit value Amin of the diameter A of the small diameter portion 16 is 9.143 mm, and the upper limit value Amax is 9.556 mm. do it.

The present embodiment has the following features.
(1) In this embodiment, the inner peripheral surface of the through-hole 12 of the washer 10 is a non-female screw part in which a female screw is not formed. Further, the non-female screw portion has a small diameter that engages between the screw thread portions 22a of the male screw portion 22 of the screw member 20 and prevents linear movement in the center line direction of the through hole 12 with respect to the screw thread portion 22a. Part 16. Further, when twisted around the center line O of the through-hole 12, the screw member 20 is allowed to move in the twist direction beyond the threaded portion 22 a of the male threaded portion 22, and larger than the small diameter portion 16. A large-diameter portion 14 having a diameter is provided.

  As a result, according to the washer of the present embodiment, there is an effect that a deformable material is not required and a simple configuration is not required to take a large storage space. Further, a washer can be screwed into the male screw portion of the screw member and assembled without providing a female screw in the through hole. Further, once the washer is assembled, it does not easily fall off the screw member.

(2) The large diameter portion 14 of the washer 10 of the present embodiment is formed within less than 180 ° of the entire inner peripheral surface of the through hole 12.
As a result, according to the present embodiment, the effect (1) can be achieved more reliably.

  (3) In this embodiment, the diameter A of the small-diameter portion 16 of the washer 10 is Amin calculated by the equations (1) and (2) according to the specifications of the screw member to be assembled and the thickness of the washer. ≦ A <Amax is set. In addition, the said specifications are the designation | designated of the screw of the screw member 20, the vertex diameter of a screw, a screw angle, and the pitch of a screw thread. As a result, the diameter of the small diameter portion can be easily obtained by a simple formula, and the effects (1) and (2) can be easily realized.

That is, the washer of this embodiment can be incorporated corresponding to the screw member having the above-mentioned specifications, and the incorporated washer does not easily fall off from the screw member.
(Second Embodiment)
Next, the washer 10 of the second embodiment will be described with reference to FIGS. 8, 9A, and 9B. In addition, the structure which is the same as that of 1st Embodiment, or the structure equivalent is attached | subjected the same code | symbol, the detailed description is abbreviate | omitted, and a different structure is demonstrated.

  As shown in FIG. 8, in the through hole 12 of the washer 10 having a ring shape, the small diameter portion 16 is formed in a circular shape having a diameter A centering on the center line O, and the inner surface 16a is a curved surface. Further, as a part of the inner surface 16a of the small diameter portion 16 is recessed outward in the direction opposite to the center line O, as shown in FIG. 8, the center line O extends from the recessed inner surface 14a. The large-diameter portion 14 having a radius R up to the inner surface of the small-diameter portion 16 is formed. Also in this embodiment, the washer 10 is a flat washer, and the material thereof is the same as that of the first embodiment.

  And the diameter A of the small diameter part 16 is the same as that of 1st Embodiment, using the item of the screw member 20 shown in FIG.9 (b), and the thickness t of the washer 10, and said Formula (1) and Formula Calculated in (2), the range is Amin ≦ A <Amax.

  Also in the present embodiment, as shown in FIG. 9B, when the washer 10 is screwed into the male screw portion 22, the small diameter portion 16 enters between the screw thread portions 22 a of the male screw portion 22. The diameter portion 14 exceeds the screw thread portion 22a. For this reason, the washer 10 moves along the axis O1 of the screw member 20 to the neck portion 26 while rotating around the axis O1. Then, by moving the washer 10 to a neck portion (not shown), a washer built-in screw can be obtained.

  Further, when the washer 10 is removed from the screw member 20 after the washer 10 has moved to the neck portion 26, the washer 10 needs to be rotated in the reverse direction and moved on the male screw portion 22. 10 does not fall off the screw member 20.

In addition, embodiment is not limited to the said embodiment, You may comprise as follows.
In the above embodiment, the washer is assembled to the screw member 20, but the washer may be incorporated into a knurled knob as the screw member. The knurled knob is used, for example, when a cover is attached to the main body case. The knurled knob has a head (knob), a neck part adjacent to the knob, and a male screw part adjacent to the neck part. In this case, after the knurled knob is inserted into the mounting hole of the cover, the washer is screwed into the male screw part inserted through the mounting hole and moved to the neck part.

  As shown in FIG. 10, the washer 10 may be formed in a C shape. In this case, as shown in FIG. 10, the small-diameter portion 16 has a diameter A, and the large-diameter portion 14 is a portion where the through hole 12 communicates with the outside. The radius R of the large diameter portion 14 is infinite, which is larger than that of the small diameter portion 16. Even if it does in this way, there exists an effect similar to the said embodiment.

  In the above-described embodiment, the washer is incorporated in the screw member of the single thread screw, but the same washer may be formed in the screw member of the multiple thread screw having two or more threads.

10 ... Retaining washer, 10a ... Front surface, 10b ... Back surface,
12 ... through hole, 14 ... large diameter part, 14a, 14b ... inner surface,
16: Small diameter part, 16a, 16b ... Inner surface,
20 ... Screw member, 22 ... Male screw part, 22a ... Screw thread part,
24 ... head, 26 ... neck,
30, 40 ... Plate material, 32, 42 ... Through hole, 45 ... Spring washer, 50 ... Nut,
O ... centerline, O1 ... axis,
A ... diameter, E, F, G ... point, R ... diameter.

Claims (3)

In a retaining washer that has a through hole and is formed in a ring shape, and the through hole is inserted and attached to a screw member having a male screw part,
The inner peripheral surface of the through hole is a non-female screw part in which a female screw is not formed,
In the non-female screw part,
A small-diameter portion that engages between the threaded portions of the male threaded portion and prevents linear movement in the direction of the center line of the through-hole with respect to the threaded portion;
When twisted around the center line of the through-hole, the large-diameter portion (14) is allowed to move in the torsion direction beyond the threaded portion of the male screw portion and has a larger diameter than the small-diameter portion. And retaining washer.   2. The retaining washer according to claim 1, wherein the large-diameter portion is formed within less than 180 ° of the entire inner peripheral surface of the through hole. When the diameter of the small diameter portion is A,
3. The retaining washer according to claim 1, wherein a diameter of the small diameter portion is in a range of Amin ≦ A <Amax.
In addition,
It is.