JPS6314099Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention is based on the idea that the male screw body has a cylindrical outer surface that can freely slide in contact with the top of the female screw, and a protrusion that protrudes toward the valley of the female screw for one turn of the female screw. A series of screws are provided within the range with a center angle of 120° apart, and in the center of each of the upper and lower end surfaces of the main body, there is a slight gap between the two surfaces, which is interposed between the upper or lower end surface of the male screw main body that is vertically adjacent to the main body. The present invention relates to a male screw unit that forms a recess that engages a provided ball-shaped joint.

In this application, the above male thread unit is defined for the following reasons.

As seen in Figure 1, when bolt B ₁ is screwed into screw hole Sc and B ₁ presses against bottom surface a ₁ of Sc, if the pressing force is P ₁ , the reaction force of P ₁ is the tensile force inside the screw hole. It is expressed as stress, and has a maximum value at the position of the A ₁ plane, and is smaller than the maximum value on surfaces further away from the A ₁ plane, and the resultant force is equal to P ₁ . And the tensile stress T ₁ located on the a ₁ plane is P ₁ > T ₁ . Next, if the pressing force when bolt B ₂ is screwed in and presses the end face a ₂ of B ₁ is P ₂ , then a ₂
Similarly to the above, T ₂ located on the plane is P ₂ > T ₂ , and if the pressing force of the bolt B _o that presses the end face a _o of the bolt B _o-1 is P _o , then T _o located on the a _o plane is P _o > T _o
Therefore, P ₁ +P ₂ +...P _o >T ₁ +T ₂ +...T _o , so lower the height of each of the bolts B ₁ , B ₂ ...B _o ,
When the screws are reduced to about 1 pitch, the distance between each end face narrows, and T ₁ ...T _o increases, resulting in P ₁ +P ₂ +P ₃ ...+P _o ≒T ₁ +T ₂ +T ₃ ...+T _o . That is, the bolt B ₁ and the bottom of the screw hole, B ₁ , B ₂ ...
The pressing forces P ₁ , P ₂ ...P _o between the mutually adjacent upper and lower sides are approximated by the sum of the tensile stresses T ₁ , T ₂ ...T _o in the wall of the screw hole, for example _, when the bolt B _o-1 If the screw does not come back loose, the bolt B _o will be tightened, so each bolt is firmly tightened together and will not loosen, and tensile stress corresponding to the pressing force is distributed within the wall of the female screw hole, increasing the tightening force. (pressing force) and maintains an equilibrium state, so there is no waste of material strength. At this time, when the screw of each bolt exceeds or does not exceed one turn, the tightening force or supporting force (pressing force) acting on the threaded surface of the screw is unevenly distributed in one turn of the screw. When the top and bottom ends of the threads overlap and when they are open without overlapping, the uniform tightening characteristics of a male thread will be impaired, so one male thread per turn is defined as a male thread unit. be.

The male screw unit of the present application will be explained below with reference to illustrated embodiments. 1 is a female screw, 2 is a thread at the top of the female screw,
3 is the thread root of the female screw, 4 is the thread surface of the female screw, and 2 and 3 are both represented by imaginary lines. 5 is a male screw body, 6 is an inner cylinder surface formed by the top of a female screw, or an outer surface of the inner cylinder of the male screw body that fits and is slidable thereon, and 7, 8, and 9 are male screw bodies 5, respectively. The valley space 1 of the thread surface 4 of the female thread from the inner cylinder outer surface 6 of
The protruding portion protrudes toward zero and has a width β in the circumferential direction, and the height h from the protruding base end to the protruding end is approximately equal to one pitch P of the screw in the case of this triangular screw.
The intervals between the protrusions are such that the center angle is 120° and the protrusions are arranged in three equal parts of the circumference in the circumferential direction.

Looking at this configuration from the developed view in Figure 3, the tightening force or supporting force (or contact pressing force) P acting on the female screw of the male screw is almost evenly distributed on each of the protrusions 7, 8, and 9. The supporting force of the protrusion is P /3.

As is clear from the above structure, the threading distance in the axial direction for one turn of the valley thread formed in the valley space 10 of the female screw is defined as one pitch p, so that both ends of this thread space If the length in the axial direction is H, then H=
It is 2p. Three protrusions 7, 8, 9 are distributed at a center angle of 120 degrees at intervals of one pitch of one turn of the valley thread, and protrude in the radial direction from the cylindrical outer surface of the male threaded body. The threaded surface of this protruding portion and the threaded surface of the female thread are accurately fitted and in slidable contact relationship.

The cylindrical outer surface 6 of the male screw main body 5 can freely slide on the cylindrical inner surface formed by the locus of the peak 2 of the female screw 1, and the frictional resistance therebetween is small. This cylindrical outer surface 6
If the diameter of is Di, the outer diameter D of the male screw is Di+2h,
Also, in the axial direction from both end surfaces of the male screw body 5.
If a guide cylinder with a length of H' is provided, the length of the main body 5 is K.
is 2H'+2p or 2H'+H. This male screw main body has a disk-shaped appearance with three protrusions projecting in the radial direction on the outer periphery, and the height of each protrusion is h as described above, and the width of the protruding end is β. Further, the inclination angle α of the spiral of the protruding end with respect to the horizontal plane is given by tanα=p/πD when the male screw has a single thread. Note that there are various types of protrusions depending on the cross-sectional shape of the thread. Further, a recess 11' into which the ball-shaped connector 12 engages is provided at the center of each of the upper and lower end surfaces of the male screw main body. This ball-shaped joint is sometimes connected integrally to the end faces, but when the male screw bodies are stacked one on top of the other, it is interposed between the adjacent end faces, and is used to create a minute gap between the end faces. Frictional resistance when tightening the male screw unit can be reduced. (FIGS. 2 and 4) A male screw unit having such a shape can be manufactured with precision using a press working in the axial direction. In particular, in the case of plastic materials such as synthetic resins, light alloys, and sintered materials, it is possible to produce them by extrusion molding, which is easier to process than conventional rolling and/or cutting with automated machine tools. Differently, productivity is also excellent.

In addition, even when this male thread unit has a large turning radius of the thread, a small inclination angle α of the thread surface, and high fitting accuracy, the contact friction surface between the protrusion and the thread surface of the female thread is small, and the sliding resistance is small. Therefore, there is no need for special tools (wrenches, spanners, etc.) to tighten the male screw unit.Place the guide tube with a height of H' at the end of the male screw unit against the opening of the female screw, and gently tighten it with a screwdriver, etc. Strong tightening can be achieved by screwing in.

FIG. 4A shows an embodiment in which this male screw unit is used as a push screw. In the figure, P represents a pressing force against the object, and a pressing force of P /3 is applied to each of the protrusions 7, 8, and 9 between the threaded surface of the female screw. Also, Figure B shows the case where the male screw units are stacked vertically and used, and the pressing force of the entire male screw unit against the object is the tightening force of each male screw unit P ₁ , P ₂
is the sum of In this example, as described above, the lower male screw unit prevents the upper male screw unit from returning, resulting in a strong set screw that does not easily screw back.

Furthermore, the above-mentioned protruding portion consists of several protruding units that protrude from the cylindrical outer surface of the male thread unit into the valley space of the female thread, and each protruding unit is in contact with the threaded surface of the female thread via an oil film, although it is not shown in the figure. , or any shape that has a cross-sectional shape that allows for direct frictional contact. In this embodiment, three protrusions are arranged at a center angle of 120° apart along the valley space of the female thread, and the width β of each protrusion is set at a center angle of approximately 120° along the valley space. It can be easily understood from the above definition of the male screw unit that the protrusions can extend, and each end of the protrusion touches, so that the three protrusions as a whole can form a series of male screw threads with one pitch. The contact area of each end of this protrusion becomes an oil reservoir when screwing in the male screw unit, reducing the sliding resistance, and increasing the protrusion width β, increasing the strength of the protrusion and increasing the tightening force. The screws will not return due to external forces such as vibration.

As mentioned above, the male screw unit of this invention improves productivity.
Since it exceeds conventional technology in terms of wear resistance, precision, mobility, and tightening ability, it can be widely used in highly developed technology and is expected to contribute to the development of the industrial economy.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention. Fig. 1 is a diagram explaining the definition of a male thread unit, and Fig. 2 is a diagram showing the male thread unit of this invention. A is a plan view thereof. B is a side view C.
is a side sectional view, Figure 3 is a developed view of the male thread unit in Figure 2, and Figure 4 A is a side view when the male thread unit is used as a set screw.B is a side view when the male thread unit is used as a set screw. FIG. In the figure, 5 is the male screw body, 7, 8, 9 are protrusions,
12 is a ball-shaped joint, and 11' is a recess.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) The male screw body has a cylindrical outer surface that can freely slide in contact with the top of the female screw. They are provided in series at a central angle of 120° within the range, and are interposed between the upper and lower end surfaces of the vertically adjacent male screw bodies in the center of each of the upper and lower end surfaces of the main body, with a slight gap between both surfaces. A male screw unit that forms a recess that engages a ball-shaped joint. (2) The ball-shaped connector described in item 1 above is a male screw unit that is integrally connected to the upper or lower end surface of a male screw body.