Back to results
US 11,320,028 B2Granted
Preload detectable screw device
AssigneeThk Co., Ltd.
InventorsYuji Kubota, Hirofumi Suzuki, Takamitsu Tomiyama
Life of this patent
Estimating the term…
Abstract
In a screw device where a shim is disposed between two nuts, a screw device that can detect preload is provided. The preload detectable screw device includes: two nuts; a shim sandwiched and compressed between the two nuts; a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other; and a force sensor for detecting preload. A contact surface of at least one of the two nuts with the shim is provided with a recess, spaced apart from the coupling portion, in such a manner as to reduce the contact area. The force sensor is attached near the recess on an outer surface of the shim.
Claims20
A preload detectable screw device, comprising:
- a screw shaft including a helical outer groove;
- two nuts assembled to the screw shaft, the two nuts including a helical inner groove facing the outer groove;
- a plurality of rolling elements disposed between the outer groove of the screw shaft and the inner groove of each of the two nuts;
- a shim sandwiched and compressed between the two nuts;
- a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other;
- and
- a force sensor for detecting preload,
- wherein:
- a contact surface of at least one of the two nuts with the shim, and/or a contact surface of the shim with at least one of the two nuts, is provided with a recess, spaced apart from the coupling portion, in such a manner as to reduce the contact area,
- the force sensor is attached near the recess on an outer surface of the shim and/or an outer surface of at least one of the two nuts, and
- when the force sensor is attached to the outer surface of at least one of the two nuts, the force sensor is attached on the shim side with respect to a helical path in which the rolling elements are arranged, between the outer groove of the screw shaft and the inner groove of the nut.
8 more elements
A preload detectable screw device, comprising:
- a screw shaft including a helical outer groove;
- two nuts assembled to the screw shaft, the two nuts including a helical inner groove facing the outer groove;
- a plurality of rolling elements disposed between the outer groove of the screw shaft and the inner groove of each of the two nuts;
- a shim sandwiched and compressed between the two nuts;
- a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other;
- and
- a force sensor for detecting preload,
- wherein:
- a contact surface of at least one of the two nuts with the shim, and/or a contact surface of the shim with at least one of the two nuts, is provided with a recess, spaced apart from the coupling portion, in such a manner as to reduce the contact area,
- the force sensor is attached near the recess on an outer surface of the shim and/or an outer surface of at least one of the two nuts, and
- as viewed in an axial direction of the nut, a first fan-shaped virtual area of the nut delimited by a sensitive portion of the force sensor is included in a second fan-shaped virtual area of the nut delimited by the recess.
8 more elements
A preload detectable screw device, comprising:
- a screw shaft including a helical outer groove;
- two nuts assembled to the screw shaft, the two nuts including a helical inner groove facing the outer groove;
- a plurality of rolling elements disposed between the outer groove of the screw shaft and the inner groove of each of the two nuts;
- a shim sandwiched and compressed between the two nuts;
- a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other;
- and
- a force sensor for detecting preload,
- wherein:
- a contact surface of at least one of the two nuts with the shim is provided with a recess, spaced apart from the coupling portion, in such a manner as to reduce the contact area,
- the force sensor is attached near the recess on an outer surface of the shim, and
- an outside diameter of the shim is less than an outside diameter of the two nuts.
8 more elements
A preload detectable screw device, comprising:
- a screw shaft including a helical outer groove;
- two nuts assembled to the screw shaft, the two nuts including a helical inner groove facing the outer groove;
- a plurality of rolling elements disposed between the outer groove of the screw shaft and the inner groove of each of the two nuts;
- a shim sandwiched and compressed between the two nuts;
- a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other;
- and
- a force sensor for detecting preload,
- wherein:
- a contact surface of at least one of the two nuts with the shim, and/or a contact surface of the shim with at least one of the two nuts, is provided with a recess, spaced apart from the coupling portion, in such a manner as to reduce the contact area,
- the force sensor is attached near the recess on an outer surface of the shim and/or an outer surface of at least one of the two nuts,
- the shim includes a pair of arc-shaped split shims, and
- a pair of keyways where a pair of keys as the coupling portions are fitted is formed in the pair of split shims.
9 more elements
A preload detectable screw device, comprising:
- a screw shaft including a helical outer groove;
- two nuts assembled to the screw shaft, the two nuts including a helical inner groove facing the outer groove;
- a plurality of rolling elements disposed between the outer groove of the screw shaft and the inner groove of each of the two nuts;
- a shim sandwiched and compressed between the two nuts;
- a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other;
- and
- a force sensor for detecting preload,
- wherein:
- a contact surface of at least one of the two nuts with the shim, and/or a contact surface of the shim with at least one of the two nuts, is provided with a recess, spaced apart from the coupling portion, in such a manner as to reduce the contact area,
- the force sensor is attached near the recess on an outer surface of the shim and/or an outer surface of at least one of the two nuts, and
- the force sensor includes:
- a first sensitive portion configured to detect an axial force on the shim and/or the nut, and
- a second sensitive portion configured to detect a circumferential force on the shim and/or the nut.
10 more elements
A preload detectable screw device, comprising:
- a screw shaft including a helical outer groove;
- two nuts assembled to the screw shaft, the two nuts including a helical inner groove facing the outer groove;
- a plurality of rolling elements disposed between the outer groove of the screw shaft and the inner groove of each of the two nuts;
- a shim sandwiched and compressed between the two nuts;
- a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other;
- and
- a force sensor for detecting preload,
- wherein:
- the shim is provided with at least one hole, spaced apart from the coupling portion,
- the force sensor is attached near the hole on an outer surface of the shim, and
- the force sensor is placed outside the hole.
8 more elements
A preload detectable screw device, comprising:
- a screw shaft including a helical outer groove;
- two nuts assembled to the screw shaft, the two nuts including a helical inner groove facing the outer groove;
- a plurality of rolling elements disposed between the outer groove of the screw shaft and the inner groove of each of the two nuts;
- a shim sandwiched and compressed between the two nuts;
- a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other;
- and
- a force sensor for detecting preload,
- wherein:
- the shim is provided with at least one hole, spaced apart from the coupling portion,
- the force sensor is attached near the hole on an outer surface of the shim,
- the hole comprises at least one axial hole extending in an axial direction of the shim, and
- as viewed in the axial direction of the shim, a breadth of a sensitive portion of the force sensor is less than a breadth of an area of the plurality of holes behind the force sensor.
9 more elements
A preload detectable screw device, comprising:
- a screw shaft including a helical outer groove;
- two nuts assembled to the screw shaft, the two nuts including a helical inner groove facing the outer groove;
- a plurality of rolling elements disposed between the outer groove of the screw shaft and the inner groove of each of the two nuts;
- a shim sandwiched and compressed between the two nuts;
- a coupling portion configured to couple the two nuts in such a manner as to be incapable of relative rotation to each other;
- and
- a force sensor for detecting preload,
- wherein:
- the shim is provided with at least one hole, spaced apart from the coupling portion,
- the force sensor is attached near the hole on an outer surface of the shim,
- the shim includes a pair of arc-shaped split shims, and
- each of the pair of split shims is provided with the hole.
9 more elements
Dependencies are inferred from the claim text.