A linear transmission device includes: an elongated shaft member, a moving module, a rolling unit, a return assembly, a sensor and a data receiving unit. The linear transmission device has a simple structure. The sensor is disposed at the junction of the first return pipe and the second return pipe of the return assembly to timely detect the change in the distance between the rolling elements, which can determine whether there is an abnormality in the shape of the spacers. With the sensor outputting detecting signals, it can stop the terminal immediately to confirm the condition of the workpieces and the machine, avoiding the structural damage of the machine and the workpiece caused by the continuous operation. The sensor can also serve as a medium for transferring data, further facilitating maintenance.

A linear transmission device includes: an elongated shaft member, a moving module, a rolling unit, a return assembly, a sensor and a data receiving unit. The linear transmission device has a simple structure. The sensor is disposed at the junction of the first return pipe and the second return pipe of the return assembly to timely detect the change in the distance between the rolling elements, which can determine whether there is an abnormality in the shape of the spacers. With the sensor outputting detecting signals, it can stop the terminal immediately to confirm the condition of the workpieces and the machine, avoiding the structural damage of the machine and the workpiece caused by the continuous operation. The sensor can also serve as a medium for transferring data, further facilitating maintenance.

A screw device is provided which can facilitate management of a tolerance of a recess where a circulation component is housed. A circulation component is housed in a recess of a nut with clearance. At least part of the circulation component is blocked by a lid member fixed to the nut by fastening means. Upon a centrifugal force acting on a rolling element moving along a circulation path in the circulation component, the circulation component comes into contact at three points with the recess as viewed in an axial direction.

[Problem to be Solved]

To provide a ball screw which improves the workability of assembling an end deflector to a nut body and avoids a decrease in the yield while ensuring the accuracy of assembling the end deflector to the nut body.

[Solution]

An end deflector 16 includes a main portion 30 including a ball delivery path 36 that delivers balls 28 between a rolling path 20 and a ball return path 24, a tongue portion 38 that guides the balls 28 from the rolling path 20 to the ball delivery path 36, and a pair of protruding pieces 42 and 44 that extend in the circumferential direction of each nut body 14 from either side of the tongue portion 38 with respect to the axial direction and define a ball guide groove 40 that extends between the ball delivery path 36 and the rolling path 20 in cooperation with an inner circumferential surface of a deflector holding recess 26 formed in a nut body 14. The main portion 30 has an outer circumferential surface 30A which opposes an inner circumferential surface 54B of the deflector holding recess 26 in the radial direction, a front-side portion 30Aa of the outer circumferential surface 30A with respect to a direction of insertion into the deflector holding recess 26 is offset inward in the radial direction, and at least a rear-side portion 30Ab of the outer circumferential surface 30A with respect to the direction of insertion into the deflector holding recess 26 is fitted to the inner circumferential surface 54B of the deflector holding recess 26.

Provided is a ball screw device in which a deflector can securely be prevented from falling into a nut when the deflector is attached. A ball screw device includes a ball screw shaft, a nut, rolling elements, a ball recirculation path, and a deflector. An attachment hole has a pair of first faces. The deflector has a pair of second faces that respectively face the pair of first faces in a state in which the deflector is housed in the attachment hole. The first faces of the attachment hole and the second faces of the deflector have a locking structure in which the first faces and the second faces respectively lock each other in an improper state in which a part of the deflector is inserted into the attachment hole in a posture different from a posture of the deflector housed in the attachment hole.

An external circulation ball screw consisting of a screw shaft, a screw nut, a cover, two reflow members and multiple rolling members is disclosed. The screw nut defines a mounting groove on the outer perimeter and two return holes in the mounting groove. A first half-return channel on a first step in the mounting groove of the screw nut and a second half-return channel in a second step inside the cover constitute a return channel. Alternatively, a third step can be formed in the cover, or the screw nut can be configured to provide a mounting groove and a third step with return holes in the mounting groove. Thus, same size of reflow members can be used with different lengths of return channels.

To prevent the positional precision of the ball return passage and the tongue of the end deflector relative to the nut main body from being impaired by an axial force applied by a screw used for securing the end deflector to the nut main body, the end deflector includes a flange (32) provided at an axial end of a main part (30) of the end deflector and provided with an axial through hole (50) for receiving a screw which is threaded into the nut main body, and a rib (52) projecting from a radially inner edge of the flange to an inner side of the deflector receiving recess (26).

A ball screw structure with detection function includes a screw shaft having an external screw groove; a nut mounted to the screw shaft to be movable in an axial direction of the screw shaft and having an internal screw groove, which corresponds to the external screw groove of the screw shaft to define a loading channel between the internal screw groove of the nut and the external screw groove of the screw shaft; a ball assembly movable, through rolling, in the loading channel; and a recirculation member directly mounted to the nut and provided thereon with a microcontroller and a sensor to detect a rotation state of the screw shaft inside the nut and further formed with a recirculation passage in communication with the nut to allow the ball assembly to move and recirculate therethrough.

A rack assist electric power steering apparatus. Shock between a rotary support member and a housing is absorbed. Backlash and friction in the rotary support member are reduced. The length of a ball nut is minimized, and the rotary support member is supported by a portion in which the ball nut and a rack bar are coupled, so that noise is reduced.

An external circulation ball screw consisting of a screw shaft, a screw nut, a cover, two reflow members and multiple rolling members is disclosed. The screw nut defines a mounting groove on the outer perimeter and two return holes in the mounting groove. A first half-return channel on a first step in the mounting groove of the screw nut and a second half-return channel in a second step inside the cover constitute a return channel. Alternatively, a third step can be formed in the cover, or the screw nut can be configured to provide a mounting groove and a third step with return holes in the mounting groove. Thus, same size of reflow members can be used with different lengths of return channels.