A bicycle crankarm the bicycle transmission side that has a main body length measured along a length from a crankset's crankarm rotation axis to a pedal axis. The crankarm has at least one stress/strain detector oriented along the length direction at a fixed distance, measured from the center of the stress/strain detector to the rotation axis of the crankarm, such that the ratio of the distance and the length is in the range between 0.45-0.65.

A torque sensor which can detect a torque with high accuracy is provided. First structure and second structure are connected by a plurality of third structures. First and second strain sensors are connected between the first structure and the second structure. Each of the first and second strain sensors includes a strain body connected between the first structure and the second structure and a plurality of sensor elements provided on the strain body. The sensor elements are disposed in a region of one side of each of the first structure and the second structure with respect to a longitudinal central portion of the strain body, and the region on the one side is a region where there is only a little difference in strain between along a torque direction of the strain body and a torque-excepted direction.

A torque sensor includes: a strain body; and an optical sensor configured to detect a deformation of the strain body. The strain body includes an outer peripheral portion having a ring shape, and an inner peripheral portion of which at least a part is disposed inside the outer peripheral portion in a radial direction. The optical sensor includes a scale fixed to one of the outer peripheral portion and the inner peripheral portion, and disposed between the outer peripheral portion and the inner peripheral portion, and a detector fixed to a remaining one of the outer peripheral portion and the inner peripheral portion, and disposed to face the scale between the outer peripheral portion and the inner peripheral portion.

The present invention relates to a load torque detection technology, and more particularly, to a device and method for load torque detection in a robot system. According to an embodiment of the present invention, it is possible to accurately detect the load torque without requiring a position sensor included in a load torque measurement actuator to have a multi-revolution function or additional power supply.

A torque measurement system includes a first rotatable carrier structure mechanically coupled to a rotational shaft; a second rotatable carrier structure mechanically coupled to the rotational shaft; a first mutually coupled structure including a first track mechanically coupled to the first rotatable carrier structure and a second track mechanically coupled to the second rotatable carrier structure, where the first track and the second track are coupled together by a first torque dependent coupling; a second mutually coupled structure including a third track mechanically coupled to the first rotatable carrier structure and a fourth track mechanically coupled to the second rotatable carrier structure, where the third track and the fourth track are coupled together by a second torque dependent coupling. In response to a rotation of the rotational shaft, the first torque dependent coupling is configured to increase and the second torque dependent coupling is configured to decrease.

The present invention provides a torque sensor that is small and highly rigid and for which high production efficiency is possible. An annular deformation body (50) is disposed between a left side support body (10) and a right side support body (20). Protruding parts (11, 12) of the left side support body (10) are joined to two upper and lower sites on the left side surface of the annular deformation body (50), and protruding parts (21, 22) of the right side support body (20) are joined to two left and right sites on the right side surface of the annular deformation body (50). The annular deformation body (50) has, at four sites, detection parts (D1 to D4) that cause elastic deformation, the right side surface of each of the detection parts (D1 to D4) moves close to or moves away from the opposing surface of the right side support body (20) when torque around the Z axis is exerted on the left side support body (10) in a state that a load is applied to the right side support body (20). A displacement electrode is formed on a right side surface of each of the detection parts (D1 to D4) and a fixed electrode is formed on an opposing surface of the right side support body (20) to constitute four sets of capacitive elements, thereby detecting torque exerted as fluctuation in capacitance value thereof.

The present invention provides a torque sensor that is small and highly rigid and for which high production efficiency is possible. An annular deformation body (50) is disposed between a left side support body (10) and a right side support body (20). Protruding parts (11, 12) of the left side support body (10) are joined to two upper and lower sites on the left side surface of the annular deformation body (50), and protruding parts (21, 22) of the right side support body (20) are joined to two left and right sites on the right side surface of the annular deformation body (50). The annular deformation body (50) has, at four sites, detection parts (D1 to D4) that cause elastic deformation, the right side surface of each of the detection parts (D1 to D4) moves close to or moves away from the opposing surface of the right side support body (20) when torque around the Z axis is exerted on the left side support body (10) in a state that a load is applied to the right side support body (20). A displacement electrode is formed on a right side surface of each of the detection parts (D1 to D4) and a fixed electrode is formed on an opposing surface of the right side support body (20) to constitute four sets of capacitive elements, thereby detecting torque exerted as fluctuation in capacitance value thereof.

A method of determining a torque applied to a rotatable shaft is provided. The method includes transmitting a first electro-magnetic transmit signal towards a first mutually coupled structure mechanically coupled to the rotatable shaft, converting, by the first mutually coupled multitrack structure, the first electro-magnetic transmit signal into a first electro-magnetic receive signal; receiving the first electro-magnetic receive signal; evaluating the received first electro-magnetic receive signal; and determining the torque applied to the rotatable shaft based on the evaluated first electro-magnetic receive signal.

A flexplate stress measurement system includes a flexplate being positioned between at least two components of a drive train of a vehicle. The flexplate is enclosed within the drive train and under operating conditions, is exposed to stress. At least one magnetic field sensing coil sensor is adapted and configured for measuring the stress acting on the flexplate under operating conditions within the drive train. The magnetic field sensing coil sensor being located on or in close proximity to the flexplate.

A series elastic actuator includes a gear configured to rotate, an output body configured to rotate by the gear, and an elastic body connecting the gear and the output body. The elastic body may include an outer ring fastened to the gear, an inner ring positioned inside the outer ring and fastened to the output body, and a deformation portion connecting the outer ring and the inner ring and deforming elastically. The elastic body may include a plurality of elastic bodies connected in parallel or in series.