Abstract: There is provided a seizure prevention bolt capable of preventing seizure caused by oblique insertion as well as seizure caused by invasion of a foreign matter such as a spatter. An incomplete screw portion having an outer diameter d that is larger than an inner diameter D1 of a female screw and smaller than (D+D1)/2 is formed at a front end of a normal screw portion formed in a bolt shaft over one or more pitches, and a vertical groove for cutting out a foreign matter such as a spatter is formed in the incomplete screw portion. D in the above expression is a nominal diameter of the bolt.

Abstract: Provided is a nut into which a bolt (10) including a male-threaded portion with a male-threaded external diameter d and a male-threaded core diameter d1 is screwed, wherein a bolt insertion side end of a female-threaded portion (21) formed in a nut body (20) is provided with an incompletely threaded female portion (22) that is formed by one to three pitches so that an internal diameter dimension D is larger than (d+d1)/2 and is smaller than the male-threaded external diameter d. Accordingly, even when the bolt is screwed into the nut in the inclination direction, the bolt may be rotated about a contact surface with respect to the incompletely threaded female portion (22), and hence seizing may be prevented.

Abstract: There is provided a seizure prevention bolt capable of preventing seizure caused by oblique insertion as well as seizure caused by invasion of a foreign matter such as a spatter. An incomplete screw portion 12 having an outer diameter d that is larger than an inner diameter D1 of a female screw 20 and smaller than (D+D1)/2 is formed at a front end of a normal screw portion 11 formed in a bolt shaft over one or more pitches, and a vertical groove 14 for cutting out a foreign matter such as a spatter is formed in the incomplete screw portion 12. D in the above expression is a nominal diameter of the bolt.

Abstract: Provided is a nut into which a bolt (10) including a male-threaded portion with a male-threaded external diameter d and a male-threaded core diameter d1 is screwed, wherein a bolt insertion side end of a female-threaded portion (21) formed in a nut body (20) is provided with an incompletely threaded female portion (22) that is formed by one to three pitches so that an internal diameter dimension D is larger than (d+d1)/2 and is smaller than the male-threaded external diameter d. Accordingly, even when the bolt is screwed into the nut in the inclination direction, the bolt may be rotated about a contact surface with respect to the incompletely threaded female portion (22), and hence seizing may be prevented.

Abstract: A navigation apparatus which accepts an operation of an operation button displayed on a display part, the navigation apparatus including: a vehicle operation detector detecting a vehicle operation when the vehicle travels; a driver characteristics learning mechanism learning driver characteristics of a driver based on the driver operation information; and a display manner changing mechanism changing a display manner of the operation button according to a learning result of the driver characteristics learning mechanism.

Abstract: A tapping screw fastened to a subject member in which a thread portion formed in a shaft portion of the tapping screw is used to form a female screw thread in a prepared hole of the subject member. An angle of a thread ridge is approximately 30 degrees, a plurality of notches are formed in a top portion of the thread portion over a predetermined range of an entire length of the shaft portion, and a joint portion for connecting the top portion and a bottom portion of the thread portion is formed to have a circular arc shape in an area having a smaller diameter than a diameter of the prepared hole of the subject matter, as viewed in a cross section including a shaft center of the tapping screw.

Abstract: The tapping screw has a screw thread having a non-circular shape. Accordingly, when the tapping screw is screwed into the prepared hole formed in the attached member such as a steel plate, etc., the contact area of the screw thread and the circumferential face of the prepared hole of the attached member can be reduced in comparison with the screw thread having a circular outer shape. Accordingly, the screwing torque can be reduced. Further, since the top portion of the screw thread of the square outer shape has a rising shape without being broken, the biting property of the screw thread with respect to the prepared hole formed in the attached member is improved so that a female screw can be precisely threaded on the inner circumferential face of the prepared hole by the screw thread.

Abstract: A tapping screw fastened to a subject member in which a thread portion formed in a shaft portion of the tapping screw is used to form a female screw thread in a prepared hole of the subject member. An angle of a thread ridge is approximately 30 degrees, a plurality of notches are formed in a top portion of the thread portion over a predetermined range of an entire length of the shaft portion, and a joint portion for connecting the top portion and a bottom portion of the thread portion is formed to have a circular arc shape in an area having a smaller diameter than a diameter of the prepared hole of the subject matter, as viewed in a cross section including a shaft center of the tapping screw.