A bearing device includes: at least one bearing that has a rolling element and a raceway surface to support a main shaft; a member disposed on a path through which pressing force generating a preload between the rolling element and the raceway surface is transmitted; and at least one load sensor element fixed to the member to measure the pressing force. At least one load sensor element is a chip component including a thin film pattern of which resistance changes according to the pressing force and a protective layer that insulates and protects thin film pattern.

A shaft assembly may include two or more Poka-Yoke bearing caps, each Poka-Yoke bearing cap having a pair of reference bores offset from a central axis of the bearing cap by differing offset distances, and each bearing cap defining a semi-circular recess that is positioned so as to align in use a central axis of the semi-cylindrical recess in the bearing cap with an axis of rotation of a shaft rotatably supported by the bearing cap. The differing offsets of the reference bores prevent the bearing cap from being assembled in a reversed orientation. To ensure that each bearing cap can only be fitted in one position, a centre spacing between the first and second reference bores of each bearing cap is different to the centre spacing used for other bearing caps used to support a single shaft.

The bearing seat device includes a bearing seat, a bearing set, a driven module, and an adjusting member. The bearing seat has a mounting hole, an adjusting slot, and an inserting hole. The adjusting slot divides a section of the bearing seat that is adjacent to the inserting hole and the mounting hole into a first side compartment and a second side compartment. The inserting hole extends from the first side compartment to the second side compartment. The bearing set is mounted in the mounting hole. The driven module extends into the mounting hole, is supported by the bearing set, and is rotatable relative to the bearing seat. The adjusting member engages the mounting hole and is operable to adjust a width of the adjusting slot between the first and the second side compartments and a diameter of the mounting hole.

The bearing seat device includes a bearing seat, a bearing set, a driven module, and an adjusting member. The bearing seat has a mounting hole, an adjusting slot, and an inserting hole. The adjusting slot divides a section of the bearing seat that is adjacent to the inserting hole and the mounting hole into a first side compartment and a second side compartment. The inserting hole extends from the first side compartment to the second side compartment. The bearing set is mounted in the mounting hole. The driven module extends into the mounting hole, is supported by the bearing set, and is rotatable relative to the bearing seat. The adjusting member engages the mounting hole and is operable to adjust a width of the adjusting slot between the first and the second side compartments and a diameter of the mounting hole.

A data collection apparatus includes an input portion to which a result of detection (heat flux) by a heat flux sensor provided in a beating is provided and a controller configured to collect the result of detection by the sensor provided to the input portion in prescribed sampling cycles for storage. When magnitude of the heat flux is smaller than a switching threshold value, the controller sets the sampling cycle to a first cycle, and when magnitude of the heat flux is larger than the switching threshold value, the controller switches the sampling cycle to a second cycle shorter than the first cycle and determines whether or not there is a sign of abnormality of the bearing based on a rate of change in heat flux collected in the second cycles.

A tool arrangement, including a tool spindle having a fixed first part and a second part rotatably mounted relative to the first part. The second part carries a tool. A drive motor having a stator and a rotor rotates the second part relative to the first part. The first part is formed by the stator and the second part is formed by the rotor. The stator includes a first bearing that supports the rotor at a first axial position and a second bearing that supports the rotor at a second axial position. The first bearing has an inner ring arranged on the outer circumference of the stator, and an outer ring arranged on an inner cylindrical surface of the rotor. The second bearing has an outer ring arranged on an inner cylindrical surface of the stator and an inner ring arranged on an outer cylindrical surface of a cover that is connected to the rotor.

A bearing device is provided which includes a first bearing, spacers, and a second bearing disposed on the outer periphery of a spindle so as to be axially located side by side. The first bearing and the second bearing each include an inner ring, an outer ring, and a plurality of rolling elements. The spacers are an inner ring spacer disposed between the inner rings of the first and second bearings, and an outer ring spacer disposed between the outer rings of the first and second bearings. One of the inner ring spacer and the outer ring spacer is a fixed spacer divided into a first member and a second member, and a circuit board is disposed in a space between the first member and the second member.