Reduction gear

Patent metadata

Field	Value
Publication number	US-11268594-B2
Application number	US-201816755735-A
Country	US
Kind code	B2
Filing date	Oct 4, 2018
Priority date	Oct 17, 2017
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

Provided is a reduction gear comprising a bearing state detection device capable of detecting the state of a rolling bearing that rotates integrally with an output shaft and an output gear during power transmission. The bearing state detection device comprises: a plurality of displacement sensors (1, 2, 11, 12), which are disposed in mutually differing positions at the sides of output gears (26, 27) having helical threads (35a, 37a) formed in the outer peripheral surfaces, and which detect the amount of axial displacement of the side surfaces of the output gears; and a processing unit (5), which determines the amount of tilt of the gears (26, 27) on the basis of the amount of displacement detected by the plurality of displacement sensors (1, 2, 11, 12) during rotation of the output gears (26, 27) when the output gears are linked to an output shaft (25) by a linking mechanism (32).

First claim

The invention claimed is:

1. A reduction gear comprising:
a casing;
an input shaft that is rotatably supported on the casing;
at least one input gear that is fixed to the input shaft, and that rotates together with the input shaft;
an output shaft that is rotatably supported on the casing such that the output shaft is disposed in parallel with the input shaft;
at least one rolling bearing including an inner ring that is fixed to the output shaft and an outer ring that is relatively rotatable to the inner ring;
at least one output gear that is fixed to the outer ring of the at least one rolling bearing and that engages with the at least one input gear;
a linking mechanism that bypasses the at least one rolling bearing and links the at least one output gear with the output shaft such that the at least one output gear and the output shaft integrally rotate; and
a detection device that detects a state of the at least one rolling bearing, wherein:
the at least one input gear includes an input-gear outer circumferential part on which helical threads are formed;
the at least one output gear includes
an output-gear outer circumferential part on which helical threads that engage with the helical threads of the input-gear outer circumferential part are formed, and
an output-gear side surface that is orthogonal to an axial direction of the output shaft; and

the detection device includes
a plurality of displacement sensors that are opposed to the output-gear side surface of the at least one output gear at a position at a predetermined distance from a rotation axis of the output shaft in a radial direction, and that detect a displacement of the output-gear side surface in the axial direction, and
a processing unit that acquires a tilt amount to the rotation axis of the output-gear side surface based on the displacements of the output-gear side surface detected by the plurality of displacement sensors in rotation of the output gear that is linked with the output shaft by the linking mechanism.

2. The reduction gear according to claim 1 ,
wherein: the plurality of displacement sensors include four displacement sensors that are disposed, being spaces to each other at an angle of 90° about the rotation axis of the output shaft; and
the processing unit operates the tilt amounts of the output-gear side surface in directions of two right angles based on the displacement of the output-gear side surface detected by two pairs of displacement sensor pairs that are opposed to each other, sandwiching the rotation axis among the four displacement sensors and combines the operated tilt amounts in the directions of two right angles.

3. The reduction gear according to claim 1 ,
wherein: the plurality of displacement sensors include three displacement sensors that are disposed about the rotation axis of the output shaft, being spaced to each other; and
the processing unit operates the tilt amount of the output-gear side surface based on the displacements of the output-gear side surface detected by the three displacement sensors.

4. The reduction gear according to claim 3 ,
wherein the three displacement sensors are disposed about the rotation axis of the output shaft, being spaced to each other at an angle of 120°.

5. The reduction gear according to claim 1 ,
wherein: the plurality of displacement sensors include two displacement sensors disposed about the rotation axis of the output shaft, being spaced to each other at an angle of 180°; and
a direction in which the two displacement sensors are connected and a direction in which the input gear is connected to the output gear viewed from a direction in parallel with the rotation axis of the output shaft are the same directions.

6. The reduction gear according to claim 1 ,
wherein: the rolling bearing further includes a rolling element that is disposed between the inner ring and the outer ring; and
the processing unit estimates a clearance amount between the inner ring or the outer ring of the rolling bearing and the rolling element based on the tilt amount of the output-gear side surface.

7. The reduction gear according to claim 1 ,
wherein: the rolling bearing further includes a rolling element that is disposed between the inner ring and the outer ring; and
the processing unit estimates a clearance amount between the inner ring or the outer ring of the rolling bearing and the rolling element based on the tilt amount of the output-gear side surface, on one hand, estimates the clearance amount based on a mean value of the displacements of the output-gear side surface detected by the plurality of displacement sensors, and selects a larger clearance amount from the two estimated clearance amounts as the clearance amount that is final.

8. The reduction gear according to claim 1 ,
wherein: the at least one input gear includes a low-speed side input gear and a high-speed side input gear;
the at least one output gear includes a low-speed side output gear that engages with the low-speed side input gear and a high-speed side output gear that engages with the high-speed side input gear;
the linking mechanism selectively links one of the low-speed side output gear and the high-speed side output gear with the output shaft; and
the plurality of displacement sensors are disposed opposite to the output-gear side surface of at least one output gear of the low-speed side output gear and the high-speed side output gear.

Assignees

• Kobe Steel Ltd

Inventors

• Okada Toru
• Yamaguchi Kazuo
• Kanai Keita

Classifications

• F16H3/083

  with radially acting and axially controlled clutching members, e.g. sliding keys · CPC title

• F16H57/01 Primary

  Monitoring wear or stress of gearing elements, e.g. for triggering maintenance · CPC title

• F16H59/042

  comprising a final actuating mechanism · CPC title

• F16H3/089 Primary

  all of the meshing gears being supported by a pair of parallel shafts, one being the input shaft and the other the output shaft, there being no countershaft involved · CPC title

• G01M13/04

  Bearings · CPC title