JP6889918B2 - Male screw and male screw mounted product - Google Patents

Description

The present invention relates to a male screw such as a screw and a bolt, and a male screw-mounted product to which the same male screw is mounted.

Conventionally, as a male screw to be screw-fitted to a female screw, various male screws have been proposed for preventing a fitting failure in which smooth and accurate screwing to the female screw is hindered. For example, in Patent Document 1 below, a screw guide protrusion that partially protrudes on the extension line on the front side of the male screw portion is formed to uniquely define the axial position of the male screw, thereby preventing a fitting failure. A male screw member to prevent is disclosed.

Japanese Unexamined Patent Publication No. 2000-12640

However, in the male threaded member shown in Patent Document 1, a so-called incomplete threaded portion formed of a threaded thread that is less than the height of the thread of the regular male thread is formed at the tip of the male thread. There is a problem that fitting failure occurs when screwing in. That is, in the conventional male-threaded member, the male-threaded member tends to incline at the initial stage of screwing the male-threaded member into the female-threaded portion, and when the male-threaded member inclines, each screw including each incomplete male-threaded and female-threaded portion. There is a problem that they come into contact with each other at two different positions on the mountain at the same time, and when they are further tightened, they are strongly pressed against each other and become immobile, which hinders smooth and accurate screwing.

The present invention has been made to address the above problems, and an object of the present invention is to provide a male screw and a male screw mounting product capable of ensuring smooth and accurate screwing into a female screw.

In order to achieve the above object, a feature of the present invention is to use a male screw having a male screw portion formed on the outer surface of the shaft body to be screw-fitted to the female screw portion formed on the inner peripheral surface of the cylinder. A leading protrusion that is formed to partially protrude at a position adjacent to the tip of the same male thread on the extension line of the part and fits into the female thread, and the frontmost side opposite to the tip of the male thread. With a low-high threaded portion formed with a thread height of less than the regular thread height of the male threaded portion, the leading protrusion is more than half the regular threaded height of the male threaded portion. Moreover, it is formed at a height equal to or lower than the regular height, and the tip portion of the male screw portion is formed at the regular height of the screw thread.

According to the feature of the present invention configured in this way, the male screw is screw-fitted (hereinafter, also referred to as “screw”) in advance of the female screw by the leading protrusion, until one rotation is performed. Since the male screw part does not fit into the female screw part and the height of the thread at the tip of the male screw part is formed to the regular height from the beginning, the male screw is in a tilted state. It is prevented that the threaded portion starts to be screwed into the female threaded portion. Further, in the male screw according to the present invention, the first (front row) thread on the opposite side of the preceding protrusion in the male screw portion is formed to be lower than the normal height, so that the male screw portion is formed in the female screw portion. During one rotation after screwing, it is prevented from coming into contact with the threads of the female thread at two different points. As a result, in the male screw according to the present invention, smooth and accurate screwing into the female screw can be ensured.

Further, another feature of the present invention is that in the male screw, the shaft body has a guide portion extending forward from the leading protrusion.

According to another feature of the present invention configured as described above, since the male screw has a guide portion on the front side of the leading protrusion and is inserted in the female screw portion in advance, the leading protrusion and the male screw are inserted. It is possible to prevent the male screw from tilting when each of the screw portions is fitted into the female screw portion, and to smoothly fit the leading protrusion and the male screw portion into the female screw portion.

Further, another feature of the present invention is that in the male screw, the guide portion has a diameter-expanded guide portion having an outer diameter larger than the outer diameter of the shaft body.

According to another feature of the present invention configured as described above, the male screw is formed in a case where the male screw portion is formed to have a smaller diameter than the female screw portion and the male screw portion is formed so as to easily enter the female screw portion. In addition, since the diameter expansion guide part is guided by contacting the female screw part, it can be smoothly fitted to the female screw part without tilting the male screw, and the female screw is used in the use of products using the male screw. Even when the fitting tolerance of the screw between the screw and the screw is loose, that is, the fitting tolerance is large, the male screw can be smoothly fitted to the female screw portion without being tilted.

Another feature of the present invention is that in the male screw, the leading protrusion is on the outer peripheral surface of the shaft body along the male screw portion in a length range of 1/4 or less of the peripheral length of the outer peripheral surface. It is in being formed. In this case, the leading protrusion can be formed by extending the top portion linearly or planarly along the male thread portion adjacent to the top portion, and forming the top portion by sharpening the leading protrusion. The whole can be formed in a triangular pyramid shape or a quadrangular pyramid shape.

According to another feature of the present invention configured as described above, in the male screw, the leading protrusion is formed on the outer peripheral surface of the shaft body in a length range of 1/4 or less of the peripheral length of the outer peripheral surface. Therefore, by allowing a slight inclination of the male screw while restricting the axial position of the male screw, the leading protrusion can be easily and quickly advanced in the female screw portion.

Further, another feature of the present invention is that in the male screw, each tip of the male screw portion and the leading protrusion is chamfered. In this case, the chamfer is an inclined surface formed in a flat or curved shape so that each tip of the male screw portion and the leading protrusion gradually rises along the screwing direction, and is formed on the outer peripheral surface of the shaft body. It is preferable to form the outer peripheral surface in a length range of 1/8 or less of the peripheral length.

According to another feature of the present invention configured in this way, the male screw is inserted into the groove of the female screw portion because the end faces of the male screw portion and each tip portion of the preceding protrusion are chamfered. It can be easily crowded.

Another feature of the present invention is that, in the male screw, the low-high screw portion and the low-high screw portion are the front and rear male screws in the screwing direction of the male screw portion in the low-high screw portion. It has a gradual change part whose height gradually decreases with respect to the part.

According to another feature of the present invention configured in this way, the height of the male screw gradually decreases and gradually changes with respect to the front and rear male screw portions of the low and high screw portions. Since the portion is provided, the male screw portion can be easily and quickly advanced in the female screw portion while preventing the male screw portion from coming into contact with the female screw portion.

Further, the present invention can be implemented not only as an invention of a male screw, but also as an invention of a product equipped with a male screw equipped with the male screw.

Specifically, the male screw-mounted product may have the male screw according to any one of claims 1 to 5 attached to the surface layer of the component. In this case, the male screw-mounted product is attached by screwing the male screw to the female screw formed on the product itself or the nut attached to the product, and specifically, for example, an engine, a transmission, and the like. These include automobile parts such as seats or car bodies, various electrical appliances, and furniture such as desks, chairs or shelves. According to this, the male screw-mounted product can be expected to have the same effect as the male screw.

It is a perspective view which shows schematic appearance structure of the male screw which concerns on one Embodiment of this invention. It is a partially enlarged view which shows the structure of the main part of the male screw shown in FIG. 1 together with the cross section of a female screw. Partial plan view and partial front view in which only one circumference on the tip side of the male screw portion and the leading protrusion are extracted in order to explain the shape and relationship of the low-high screw portion and the leading protrusion in the male screw shown in FIG. Is. It is a partially enlarged view which shows the state which the guide part in the male screw shown in FIG. 2 is inserted into the female screw part. It is a partially enlarged view which shows the state which the tip part of the male screw part of the male screw shown in FIG. 2 is inserted into the female screw part. FIG. 5 is a partially enlarged view showing a state in which the male screw shown in FIG. 5 is rotated half a turn and the male screw portion is further inserted into the female screw portion. FIG. 6 is a partially enlarged view showing a state in which the male screw shown in FIG. 6 is inclined toward the leading protrusion. FIG. 6 is a partially enlarged view showing a state in which the male screw shown in FIG. 6 is inclined to the side opposite to the leading protrusion side. FIG. 5 is a partially enlarged view showing a state in which the male screw shown in FIG. 5 is rotated twice and the male screw portion is further inserted into the female screw portion. It is a perspective view which shows schematic appearance structure of the male screw which concerns on other embodiment of this invention. It is a perspective view which shows schematic appearance structure of the male screw which concerns on still another Embodiment of this invention. It is a perspective view which shows schematic appearance structure of the male screw which concerns on still another Embodiment of this invention. It is a perspective view which shows schematic appearance structure of the male screw which concerns on still another Embodiment of this invention. It is a perspective view which shows schematic appearance structure of the male screw which concerns on still another Embodiment of this invention.

Hereinafter, an embodiment of a male screw and a male screw-mounted product according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view schematically showing an external configuration of a male screw 100 according to the present invention. Further, FIG. 2 is a partially enlarged view showing the configuration of the main portion of the male screw 100 shown in FIG. 1 together with the cross section of the female screw 90. It should be noted that each figure referred to in the present specification may be schematically represented by exaggerating some of the components in order to facilitate the understanding of the present invention. Therefore, the dimensions between the components are shown. And ratios may differ.

The male screw 100 is a mechanical element for attaching to a resin part (not shown) such as an intake manifold constituting an intake system in an engine of a self-propelled vehicle to another part such as a throttle body. In this case, the surface layer of another article such as the intake manifold is provided with a female screw 90 directly formed or a tubular nut on which the female screw 90 is formed embedded. Then, a resin part such as an intake manifold to which other articles such as a throttle body are attached by a male screw 100, and an engine to which a resin part such as this intake manifold is attached is a product equipped with a male screw (not shown). ) Corresponds to.

Further, the female screw 90 is configured by forming a female screw portion 91 composed of a spiral protrusion and a groove into which the male screw 100 is screw-fitted on the inner peripheral surface of the bottomed or penetrating tubular portion. Yes, it has been commonly used in the past. In this case, the female threaded portion 91 is formed with an incomplete threaded portion 92 having a thread thread that is less than the thread height of the regular female threaded portion in the opening portion on the side where the male screw 100 is screwed. There is.

Here, the incompletely threaded portion in the male and female threads is generally a shaft body (or cylinder) in which a male threaded portion (or female threaded portion) is formed from the tip of the male threaded portion (or female threaded portion). ) Is an incomplete thread having an insufficient height of a thread formed in a range of 1/4 or more of the circumferential length and 2 pitches or less of the male threaded portion (or female threaded portion). In addition, the regular thread height of the male and female threads is required for the male thread (or female thread) to screw into the female thread (or male thread) to the extent that it functions as a screw. This is the height, and includes the height of each thread of metric screw, unified screw, and wit screw specified by JIS standard, as well as the height of non-standard screw thread specified exclusively for each application.

(Structure of male screw 100)
The male screw 100 includes a shaft body 101. The shaft body 101 is a portion where a male screw portion 102, a leading protrusion 104, and a guide portion 105 are formed, respectively, and is formed by forming a metal material (for example, carbon steel) into a round bar shape. More specifically, the shaft body 101 has a male screw portion 102 formed in the central portion in the axial direction, and the leading protrusion 104 and the guide portion 105 are respectively located on the front side in the screwing direction of the male screw portion 102. It is formed. Further, the shaft body 101 is provided with a head 107 via a lower neck 106 on the rear side opposite to the front side. That is, the shaft body 101 is formed with a guide portion 105, a leading protrusion 104, a male screw portion 102, a lower neck portion 106, and a head portion 107 in this order from the lower end portion in the drawing.

The male screw portion 102 is a portion that is screw-fitted to the female screw portion 91, and is composed of a spirally extending protrusion and a groove on the outer surface of the shaft body 101. The male screw portion 102 has a chamfered tip portion 102a that first fits in the female screw portion 91, and the tip surface is behind the screwing direction (also referred to as “traveling direction”) of the male screw portion 102. It is composed of inclined surfaces that incline toward it. That is, the male screw portion 102 has the same shape as the conventional male screw except that the tip portion 102a is not formed with a so-called incomplete screw portion that is less than the height of the thread of the regular male screw.

A low-high screw portion 103 is formed on the male screw portion 102. The low-high threaded portion 103 is for preventing contact between the thread of the male threaded portion 102 and the thread of the female threaded portion 91 at the initial stage of screw fitting the male threaded portion 102 into the female threaded portion 91. It is a part. Specifically, as shown in FIG. 3, the low-high screw portion 103 is first contained in the female screw 90 among the male screw portions 102 formed on the shaft body 101 on the side opposite to the leading protrusion 104. The height of the entering screw thread (in other words, the frontmost screw thread) is formed to be lower than the height RT of the regular screw thread (indicated by the two-point chain line in FIG. 3) of the male screw portion 102. ing.

In this case, the low-high screw portion 103 is the lowest point UP having the lowest height h on the shaft body 101 at a position (in other words, a position of 180 °) opposite to the tip of the leading protrusion 104. The heights of the male threaded portion 102 toward the front and the rear (in other words, both sides of the male threaded portion 102 in the forming direction with respect to the lowest point UP) with respect to the lowest point UP, respectively. The gradual change portions 103a and 103b that become higher are formed and configured.

The height h of the low-high screw portion 103 may be a height less than the regular height RT of the thread of the male screw portion 102, but is 1/2 or more of the regular height RT and the same regular height RT. Height It is preferable that the height is less than RT. Further, the formation position of the low-high screw portion 103 is at least 90 ° or more and 270 ° or less from this position (0 °) when the position of the leading protrusion 104 on the shaft body 101 is 0 °. The point UP may be formed so as to be located, but more preferably the lowest point UP may be formed so as to be located at a position of 180 °.

Further, the formation range of the low-high screw portion 103 includes a range of at least 135 ° or more and 225 ° or less from this position (0 °) when the position of the leading protrusion 104 on the shaft body 101 is 0 °. It is preferable that the shaft body 101 is formed to have a length of 1/3 or more of the peripheral length of the shaft body 101. In the present embodiment, the low-high threaded portion 103 is formed at the lowest point UP at a height of 2/3 of the regular height RT of the thread of the male threaded portion 102, and is centered on this lowest point UP. The gradual change portions 103a and 103b, which gradually increase in height in the range of 0 ° to 360 °, are formed, respectively. That is, in the present embodiment, the height of the thread of the low-high screw portion 103 is continuously lowered by the gradual change portion 103a immediately after the tip portion 102a of the male screw portion 102, and is the lowest at the 180 ° position. After the point UP is formed, the height of the screw thread is formed so as to be continuously increased by the gradual change portion 103b from the tip portion 102a toward the position around the circumference.

The leading protrusion 104 is a portion that is screw-fitted to the female screw portion 91 prior to the male screw portion 102, and is formed so as to project convexly from the outer surface of the shaft body 101. Specifically, the leading protrusion 104 is located on the outer surface of the shaft body 101 on an extension line to the front side in the screwing direction of the male screw portion 102 and at a position adjacent to the tip portion 102a of the male screw portion 102. It is formed so as to partially protrude.

In this case, the position adjacent to the tip portion 102a of the male screw portion 102 is a position shifted to the tip side of the shaft body 101 by one pitch portion of the male screw portion 102 with respect to the tip portion 102a of the male screw portion 102. It is a peripheral position, and more specifically, a position directly beside the tip portion 102a of the male screw portion 102, and a front side and a rear side position in the screwing direction with respect to the position just beside the same. Further, the tip portion 102a does not mean only the most advanced portion of the male screw portion 102, but is a region including a portion after the most advanced portion, more specifically, at least the shaft body 101 starting from the most advanced portion. It is a part of the length range of 1/8 of the circumference.

The height of the leading protrusion 104 is formed to be ½ or more of the regular height RT of the thread of the male screw portion 102 and less than or equal to the regular height RT. Further, the length of the leading protrusion 104 is preferably formed to be 1/3 or less of the peripheral length of the outer surface of the shaft body 101, but more preferably 1/4 or less. It is good.

In the present embodiment, the leading protrusion 104 is on the outer surface of the shaft body 101 on the extension line to the front side in the screwing direction of the male screw portion 102 from a position adjacent to the tip portion 102a of the male screw portion 102. It is formed in a trapezoidal shape in a side view extending along the male screw portion 102. In this case, the leading protrusion 104 is formed at the same height as the regular height RT of the thread of the male screw portion 102, and is formed at a length of 1/5 of the peripheral length of the shaft body 101. .. Further, in the leading protrusion 104, the front end portion 104a on the front side and the rear end portion 104b on the rear side of the male screw portion 102 in the screwing direction are chamfered, and the respective front end surfaces and rear end surfaces of the male screw portion 102 are chamfered. Each of the tip portions 102a is composed of an inclined surface having the same inclination angle as the tip surface.

The guide portion 105 is a portion of the shaft body 101 that is first inserted into the female screw portion 91 to regulate the inclination of the male screw 100 with respect to the female screw portion 91, and has a round bar shape in front of the leading protrusion 104. It is formed so as to protrude from the surface. In this case, the guide portion 105 is formed to have a diameter slightly smaller than the inner diameter of the female screw portion 91, and the tip portion is formed to have a rounded shape. The length of the guide portion 105 in the axial direction is not particularly limited, but it is preferable that the guide portion 105 is formed to have a length of 1 pitch or more and 5 pitches or less of the male screw portion 102. The tip of the guide portion 105 has an outer edge portion that is rounded in an arc shape, but instead, the outer edge portion may be formed at a right angle, and the outer diameter of the guide portion 105 may be increased. It may be formed in a pointed shape that shrinks toward the tip.

The lower neck 106 is a round bar-shaped portion of the shaft body 101 on which the male screw portion 102 is not formed, and is formed between the male screw portion 102 and the head 107. The head 107 is a portion to which a tool for applying a rotational force to the shaft body 101 is detachably fitted. In the present embodiment, the head 107 is formed by extending in a flange shape to the rear end portion of the shaft body 101 and then extending in a hexagonal columnar shape in the axial direction of the shaft body 101.

That is, in the present embodiment, the male screw 100 is composed of a so-called flanged hexagon bolt. The male screw 100 is formed and manufactured by performing machining (for example, forging, rolling, or cutting) on a rod-shaped or linear metal material.

(Operation of male screw 100)
Next, the operation of the male screw 100 configured in this way will be described. First, the operator prepares an article (not shown) including a male screw 100 and a female screw 90 to which the male screw 100 is tightened. In this operation description, an article (for example, the intake manifold) that is arranged between the male screw 100 and the female screw 90 and is attached by tightening the male screw 100 to the female screw 90 will be omitted. To do.

Next, the operator tightens the male screw 100 to the female screw 90. Specifically, as shown in FIG. 4, the operator inserts the guide portion 105 of the male screw 100 into the female screw 90 and rotates the shaft body 101 in the circumferential direction (for example, clockwise). As a result, in the male screw 100, the leading protrusion 104 starts to fit into the incompletely threaded portion 92 in the female screw portion 91. In this case, since the male screw 100 is prevented from being greatly inclined with respect to the female screw 90 by the guide portion 105, the leading protrusion 104 is smoothly fitted into the female screw portion 91.

The male screw 100 cannot be completely prevented from tilting because the guide portion 105 has a diameter smaller than the inner diameter of the female screw 90 and the female screw portion 91 has an incomplete screw portion 92 formed therein. It may be tilted when it is inserted into the female screw 90. However, in the male screw 100, since the leading protrusion 104 is formed at the same height as the regular height RT of the male screw portion 102, the leading protrusion 104 is formed on the female screw portion 91 (when the inclination angle is large). It is possible to prevent fitting failure by idling without fitting to the incomplete screw portion 92). Further, the work of rotating the male screw 100 may be directly rotated by the operator's hand or may be rotated by using a tool such as a hexagon wrench.

Next, when the leading protrusion 104 is fitted to the incompletely threaded portion 92 of the female screw 90, the operator further rotates the male screw 100. As a result, as shown in FIG. 5, the male screw 100 makes one rotation after the leading protrusion 104 is fitted to the incomplete thread portion 92 of the female screw 90, and at the same time, the tip portion 102a of the male screw portion 102 is incomplete. Fitting to the threaded portion 92 is started. Even in this case, the male screw 100 is prevented from being greatly inclined with respect to the female screw 90 by the guide portion 105, and the leading protrusion 104 is fitted to the completely threaded portion of the female screw portion 91. Since the allowable amount of inclination is further reduced by starting, the male threaded portion 102 is smoothly fitted in the female threaded portion 91. In this case, in this case, the male screw portion 102 is restricted from being displaced in the axial direction of the shaft body 101 by starting to fit the leading protrusion 104 into the completely threaded portion of the male screw portion 102. is there.

Then, when the male screw 100 is half-turned after the male screw 102 is fitted to the incomplete thread 92 of the female screw 90, the low-high screw portion 103 is an incomplete screw as shown in FIG. It comes to be located in the part 92. In this case, the male screw portion 102 is formed so that the thread height h of the low-high screw portion 103 is lower than the regular thread height RT. Therefore, as shown in FIGS. 7 and 8, the male screw 100 has the peripheral surface of the thread of the low-high screw portion 103 and the screw of the female screw portion 91 even when the male screw 100 is inclined with respect to the female screw 90, respectively. By simultaneously contacting and further tightening the peripheral surfaces of the mountain at two different positions, it is possible to prevent the two from being strongly pressed against each other and becoming stuck.

Further, as shown in FIG. 9, in the male screw 100, as the male screw portion 102 is screwed into the female screw portion 91, the leading protrusion 104 and the male screw portion 102 are respectively screwed into the female screw portion 91. Since it fits into the completely threaded portion, it stands in a posture parallel to the female threaded portion 91. As a result, the male screw 100 is tightened to the female screw 90 without causing a fitting failure.

As can be understood from the above operation description, according to the above embodiment, the male screw 100 is a male screw until the leading protrusion 104 is screw-fitted in advance of the female screw 90 and makes one rotation. Since the portion 102 does not fit into the female screw portion 91 and the height of the thread of the tip portion 102a of the male screw portion 102 is formed at the regular height RT from the beginning, the male screw 100 is inclined. In this state, the male screw portion 102 is prevented from starting to be screwed into the female screw portion 91. Further, in the male screw 100 according to the present invention, the first (front row) screw thread on the opposite side of the leading protrusion 104 in the male screw portion 102 is formed to be lower than the regular height RT, so that the male screw portion is formed. During one rotation after the 102 is screwed into the female threaded portion 91, it is prevented from coming into contact with the thread of the female threaded portion 91 at two different points. As a result, in the male screw 100 according to the present invention, smooth and accurate screwing into the female screw 90 can be ensured.

Furthermore, the practice of the present invention is not limited to the above-described embodiment, and various changes can be made as long as the object of the present invention is not deviated.

For example, in the above embodiment, the male screw 100 is configured to have the guide portion 105 in a state of projecting in front of the leading protrusion 104 on the shaft body 101. However, the male screw 100 can be configured by omitting the guide portion 105.

Further, in the above embodiment, the guide portion 105 is formed to have the same outer diameter as the outer diameter of the shaft body 101, that is, the same outer diameter as the valley diameter of the male screw portion 102. However, the guide portion 105 can be formed to have an outer diameter larger than the outer diameter of the shaft body 101 (the valley diameter of the male screw portion 102). For example, as shown in FIG. 10, the male screw 100 is configured by providing a diameter-expanded guide portion 105a at the tip of the guide portion 105, which is thicker than the outer diameter of the shaft body 101 and smaller than the inner diameter of the female screw portion 91. be able to.

According to this, the male screw 100 has a diameter-expanded guide portion even when the male screw portion 102 is formed smaller than the female screw portion 91 so that the male screw portion 102 can easily enter the female screw portion 91. Since the 105a comes into contact with the female screw portion 91 and is guided, the male screw 100 can be smoothly fitted to the female screw portion 91 without being tilted. Further, the male screw 100 tilts the male screw 100 in the same manner even when the fitting tolerance of the screw between the male screw 100 and the female screw 90 is loose due to the use of the product using the male screw 100, that is, the fitting tolerance is large. It can be smoothly fitted to the female screw portion 91 without causing it.

The length of the diameter-expanding guide portion 105a in the axial direction is not particularly limited, but it is preferable that the male screw portion 102 is formed to have a length of 1 pitch or more and 5 pitches or less. Further, the tip portion of the diameter-expanded guide portion 105a is formed so that the outer edge portion is rounded in an arc shape, but instead, the outer edge portion may be formed at a right angle, or the diameter-expanded guide portion 105a may be formed. It may be formed in a sharp shape in which the outer diameter of the is reduced toward the tip portion.

Further, in the above embodiment, the leading protrusion 104 is formed at a position directly beside the tip portion 102a of the male screw portion 102. However, the leading protrusion 104 is formed on the outer surface of the shaft body 101 at a position on the extension line of the male screw portion 102 to the front side in the screwing direction and adjacent to the tip portion 102a of the male screw portion 102. Just do it. Therefore, the leading protrusion 104 can be provided on the front side or the rear side in the screwing direction with respect to the position directly beside the tip portion 102a of the male screw portion 102. In these cases, the leading protrusion 104 is located on the front side or the rear side in the screwing direction by a length of 1/8 or less of the peripheral length of the shaft body 101 with respect to the position directly beside the tip portion 102a of the male screw portion 102. Can be provided. Here, FIG. 11 shows a male screw 100 provided with the leading protrusion 104 shifted to the front side in the screwing direction with respect to a position directly beside the tip portion 102a of the male screw portion 102.

Further, in the above embodiment, the leading protrusion 104 has a substantially trapezoidal shape in a side view in which the top portion extends in a curved shape, and more specifically, the cross-sectional shape is the same as the completely threaded portion of the male screw portion 102. It was formed in the shape of a screw thread. However, the leading protrusion 104 can be formed by extending the top portion in a plane or a linear shape along the male screw portion 102 adjacent to the top portion, and the leading protrusion 104 is formed by sharpening the top portion. The body 104 as a whole can also be formed in a triangular pyramid shape. Here, FIG. 12 shows a male screw 100 in which the top portion of the leading protrusion 104 is linearly formed. Further, FIG. 13 shows a male screw 100 formed by forming a point-like pointed top portion of the leading protrusion 104. Further, FIG. 14 shows a male screw 100 formed so that the apex portion of the leading protrusion 104 is formed as a point-like point and then the apex portion is linearly inclined toward the rear.

Further, in the above embodiment, the male screw portion 102 and the leading protrusion 104 are formed by chamfering the tip portions 102a and 104a to form a flat inclined surface. As a result, the male screw 100 can be easily fitted to the female screw portion 91. In this case, the male screw portion 102 and the leading protrusion 104 can be formed of an inclined surface in which the tip portions 102a and 104a are chamfered in a curved surface. However, the male screw portion 102 and the leading protrusion 104 can be formed at a right angle by omitting the chamfering of each corner portion of each of the tip portions 102a and 104a. Further, the leading protrusion 104 may be similarly formed in a curved surface shape at the rear end portion 104b, or may be omitted and formed at a right angle.

Further, in the above embodiment, the low-high screw portion 103 is configured by forming slowly changing portions 103a and 103b having the same inclined surface on both sides of the lowest point UP, respectively. However, the low-high screw portion 103 can also be configured by forming slowly changing portions 103a and 103b formed of inclined surfaces having different inclination angles or lengths on both sides of the lowest point UP. Further, the low-high screw portion 103 can be configured by omitting the gradual change portions 103a and 103b. In this case, the low-high screw portion 103 can be configured by forming the height of the portions forming the gradually changing portions 103a and 103b to the same constant height as the lowest point UP.

Further, in the above embodiment, the male screw 100 is made of a metal material. However, the male screw 100 can also be made of a material other than metal, for example, a resin material or wood. Therefore, the male screw 100 can be used by being embedded in parts other than engine parts in a self-propelled vehicle, for example, furniture such as desks and chairs, concrete blocks, and the like. Further, the female screw 90 may be composed of a female screw portion 91 in which the incomplete screw portion 92 is omitted.

RT ... regular screw thread, UP ... lowest point, h ... height at the lowest point of low and high screw part,
90 ... Female screw, 91 ... Female thread, 92 ... Incomplete thread,
100 ... male screw, 101 ... shaft body, 102 ... male screw part, 102a ... tip part, 103 ... low and high screw part, 103a, 103b ... gradual change part, 104 ... leading protrusion, 104a ... tip part, 104b ... rear End, 105 ... guide, 106 ... lower neck, 107 ... head.

Claims (7)

In the male screw where the male screw part that is screw-fitted to the female screw part formed on the inner peripheral surface of the cylinder is formed on the outer surface of the shaft body,
A leading protrusion that is formed so as to partially project at a position adjacent to the tip of the male threaded portion on the extension line of the male threaded portion and fits into the female threaded portion.
The male screw portion includes a low-high screw portion formed so that the height of the frontmost screw thread on the side opposite to the tip portion of the male screw portion is less than the regular thread height of the male screw portion.
The leading protrusion is
It is formed at a height that is more than half of the regular height of the thread in the male screw portion and less than or equal to the regular height.
The tip of the male screw portion is
A male screw characterized in that it is formed at the regular height of the screw thread. In the male screw according to claim 1,
The shaft body is
A male screw having a guide portion extending forward from the preceding protrusion. In the male screw according to claim 2,
The guide unit
A male screw characterized by having an enlarged diameter guide portion having an outer diameter larger than the outer diameter of the shaft body. In the male screw according to any one of claims 1 to 3.
The leading protrusion is
A male screw formed on the outer peripheral surface of the shaft body along the male screw portion in a length range of 1/4 or less of the peripheral length of the outer peripheral surface. In the male screw according to any one of claims 1 to 4.
The male screw portion and the leading protrusion
A male screw characterized in that each tip is chamfered. In the male screw according to any one of claims 1 to 5.
The low-high screw portion is
A male characterized by having a gradual change portion whose height is gradually lowered with respect to each of the male screw portions on the front side and the rear side in the screwing direction of the male screw portion in the low and high screw portion. screw. A male screw-mounted product characterized in that the male screw according to any one of claims 1 to 6 is attached to the surface layer of a part.

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