A gear that can be utilized in an electric actuator has teeth formed on its outer circumference and a central hole formed at its center. An intermediate region is positioned between a peripheral portion near the teeth and a boss near the central hole. The intermediate region has a thickness thinner than the peripheral portion and the boss. A plurality of weight-lightening apertures is circumferentially and equidistantly formed in the intermediate region. A vibration absorbing member of synthetic rubber is formed on both side surfaces of the intermediate region. The vibration absorbing member is integrally connected on each side through the weight-lightening apertures. The vibration absorbing member is attached to the radially outer side rather than an outer diameter of a bearing arranged adjacent to the vibration absorbing member.

A workpiece executes a rotation movement about a longitudinal axis and is machined by a tool in a multitude of reshaping engagements, in which an active region of the tool comes into contact with the machining region. The tool is held by a tool holder. The tool holder is mounted in an orbiting body so as to be rotatable about a rotation axis and is driven to carry out a rotating movement about the rotation axis, and is driven to carry out an orbiting movement by the orbiting body. Rotation movement of the workpiece is synchronised with the orbiting movement of the tool holder and the rotating movement of the first tool holder is synchronised with the orbiting movement of the tool holder.

A workpiece executes a rotation movement about a longitudinal axis and is machined by a tool in a multitude of reshaping engagements, in which an active region of the tool comes into contact with the machining region. The tool is held by a tool holder. The tool holder is mounted in an orbiting body so as to be rotatable about a rotation axis and is driven to carry out a rotating movement about the rotation axis, and is driven to carry out an orbiting movement by the orbiting body. Rotation movement of the workpiece is synchronised with the orbiting movement of the tool holder and the rotating movement of the first tool holder is synchronised with the orbiting movement of the tool holder.

Disclosed is a roll spinning forming device for a toothed part. The device is mounted on a machine tool body. A blank, a mandrel and a driving synchromesh gear are mounted on a machine tool spindle. A driven synchromesh gear and a roller are arranged in parallel on the spindle. The driven synchromesh gear and the roller are connected by a telescopic constant speed universal joint and rotate at a same angular speed. The driven synchromesh gear is driven by a spring mechanism in the radial direction, and the roller is driven by a servo motor assembly in the radial direction. Further disclosed is a roll spinning forming method for a toothed part, the rotating speed of the blank is maintained to be matched with the rotating speed of the roller according to a gear ratio during the movement of the roller toward the blank.

Disclosed is a roll spinning forming device for a toothed part. The device is mounted on a machine tool body. A blank, a mandrel and a driving synchromesh gear are mounted on a machine tool spindle. A driven synchromesh gear and a roller are arranged in parallel on the spindle. The driven synchromesh gear and the roller are connected by a telescopic constant speed universal joint and rotate at a same angular speed. The driven synchromesh gear is driven by a spring mechanism in the radial direction, and the roller is driven by a servo motor assembly in the radial direction. Further disclosed is a roll spinning forming method for a toothed part, the rotating speed of the blank is maintained to be matched with the rotating speed of the roller according to a gear ratio during the movement of the roller toward the blank.

A sprocket for a bicycle drive train comprising an outer ring having external teeth for engaging in a bicycle chain, and an inner ring coaxially disposed with the outer ring and is connected to the outer ring in a rotationally fixed manner. The inner ring has a central opening. A circumferential collar is configured to be integral with the inner ring and projects axially to one side of the inner ring and is configured as a continuous collar. An internal profile having a plurality of radially inward-projecting radial protrusions is provided on the radially inner side of the collar, and an external profile having a plurality of radial depressions, which in number and arrangement correspond to the radial protrusions of the internal profile, is provided on the radially outer side of the collar.

A sprocket for a bicycle drive train comprising an outer ring having external teeth for engaging in a bicycle chain, and an inner ring coaxially disposed with the outer ring and is connected to the outer ring in a rotationally fixed manner. The inner ring has a central opening. A circumferential collar is configured to be integral with the inner ring and projects axially to one side of the inner ring and is configured as a continuous collar. An internal profile having a plurality of radially inward-projecting radial protrusions is provided on the radially inner side of the collar, and an external profile having a plurality of radial depressions, which in number and arrangement correspond to the radial protrusions of the internal profile, is provided on the radially outer side of the collar.

Provided are a protrusion forming device, a protrusion forming method, and a formed article, with which a height equal to or greater than the plate thickness is possible, the edges are sharp, and cracking can be prevented. This protrusion forming device is characterized by being equipped with a die unit provided with a die hole, and a punch unit having a large punch part with a size such that this part cannot be inserted into the die hole, and a small punch part that protrudes from the large punch part toward the die unit and can be inserted into the die hole, and characterized in that the workpiece is deformed by pressing a portion of the workpiece arranged between the die unit and the punch unit toward the die unit by means of the punch unit, thereby forming a protrusion.

Provided are a protrusion forming device, a protrusion forming method, and a formed article, with which a height equal to or greater than the plate thickness is possible, the edges are sharp, and cracking can be prevented. This protrusion forming device is characterized by being equipped with a die unit provided with a die hole, and a punch unit having a large punch part with a size such that this part cannot be inserted into the die hole, and a small punch part that protrudes from the large punch part toward the die unit and can be inserted into the die hole, and characterized in that the workpiece is deformed by pressing a portion of the workpiece arranged between the die unit and the punch unit toward the die unit by means of the punch unit, thereby forming a protrusion.

A robot includes a flexible gear formed by a ferrous material containing at least one or more kinds of elements of Group 4 elements and Group 5 elements in a range from 0.01 percent by mass to 0.5 percent by mass. The ferrous material contains at least one of nickel-chromium-molybdenum steel, maraging steel, and precipitation-hardened stainless steel.