Torque measurement device-equipped rotation transmission apparatus

Patent metadata

Field	Value
Publication number	US-9625332-B2
Application number	US-201414916668-A
Country	US
Kind code	B2
Filing date	Sep 3, 2014
Priority date	Sep 4, 2013
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

In order to implement a structure capable of improving the resolution of torque measurement while preventing the plastic deformation of a torsion bar ( 15 ), an input-side stopper ( 61 ) having an uneven shape (gear shape) in the circumferential direction is provided in a portion of an input-side rotating body ( 55 ) that includes an input shaft ( 13 ) and an input gear ( 7 ), and an output-side stopper ( 63 ) having an uneven shape (gear shape) in the circumferential direction is provided in a portion of an output-side rotating body ( 56 ) that includes an output shaft ( 14 ) and an output gear ( 8 ). The input-side stopper ( 61 ) and the output-side stopper ( 63 ) are combined so as to be engaged to be able to transmit torque only when the torsional angle within the elastic range of the torsion bar ( 15 ) reaches a predetermined amount.

First claim

What is claimed is:

1. A torque measurement device-equipped rotation transmission apparatus, comprising:
a rotating-shaft unit,
a connecting shaft,
a first characteristic-changing member,
a second characteristic-changing member,
one sensor unit,
a first stopper section, and
a second stopper section,
the rotating-shaft unit comprising:
a first rotating body having: a hollow first rotating shaft rotatably supported by a portion that does not rotate even during use; and a first gear provided around the outer-circumferential surface of the first rotating shaft;
a second rotating body having: a hollow second rotating shaft arranged so as to be concentric with the first rotating shaft; and rotatably supported by the portion that does not rotate even during use, and a second gear provided around the outer-circumferential surface of the second rotating shaft; and
a hollow torsion bar arranged on the inner-diameter side of the first rotating shaft and second rotating shaft so as to be concentric with the first rotating shaft and second rotating shaft, and having: one end section connected to the first rotating shaft so that relative rotation is not possible; another end section connected to the second rotating shaft so that relative rotation is not possible; and a middle section in the axial direction undergoing elastic torsional deformation when torque is being transmitted, the dimension in the axial direction being greater than the space in the axial direction between the first gear and the second gear;

the connecting shaft arranged on the inner-diameter side of the torsion bar so as to be concentric with the torsion bar, and having: one end section connected to the first rotating shaft so that relative rotation is not possible; and another end section protruding in the axial direction from the other end section of the second rotating shaft and the torsion bar;
the first characteristic-changing member fastened to the other end section of the connecting shaft so as to be concentric with the connecting shaft, and having a circular ring shaped first detected section;
the second characteristic-changing member fastened to a distal end section of the second rotating shaft with respect to the first rotating shaft so as to be concentric with the second rotating shaft, and having a circular ring shaped second detected section arranged so as to closely face the first detected section in the axial direction or in the radial direction;
the first characteristic-changing member and the second characteristic-changing member constructed to move relative to each other in the direction of rotation due to the elastic torsional deformation of the middle section in the axial direction of the torsion bar occurring when the rotating shaft unit transmits torque;
the sensor unit supported by the portion that does not rotate even during use, and constructed to generate an output signal changing according to the rotation of the first detected section and the second detected section;
the first stopper section provided on part of the first rotating body;
the second stopper section provided on part of the second rotating body, and constructed to engage with the first stopper section so that torque can be transmitted only when the torsional angle of the torsion bar reaches a specified amount within the elastic range of the torsion bar; and
the torque measurement device-equipped rotation transmission apparatus capable of measuring the torque that the rotating-shaft unit transmits according to the change in the output signal from the sensor unit due to relative displacement in the direction of rotation of the first characteristic-changing member and the second characteristic changing member.

2. The torque measurement device-equipped rotation transmission apparatus according to claim 1 , wherein the outer-circumferential surface of the middle section in the axial direction of the connecting shaft is guided and supported by the inner-circumferential surface of the torsion bar.

3. The torque measurement device-equipped rotation transmission apparatus according to claim 1 , wherein a sliding bearing is provided between the inner-circumferential surface of the other end section of the second rotating shaft and the outer-circumferential surface of the connecting shaft or fitting section of the first characteristic-changing member that fits with the connecting shaft.

4. The torque measurement device-equipped rotation transmission apparatus according to claim 1 , wherein a rim section is provided around the outer-circumferential surface of the one end section of the connecting shaft, and by press-fitting the rim section with the inner-circumferential surface of a distal end section of the first rotating shaft with respect to the second rotating shaft, the connecting shaft is supported so that relative rotation with respect to the first rotating shaft is not possible.

5. The torque measurement device-equipped rotation transmission apparatus according to claim 1 , wherein
the second rotating shaft is rotatably supported with respect to the portion that does not rotate even during use by a rolling bearing that is located between a portion of the outer-circumferential surface of the second rotating shaft that is near the distal end with respect to the first rotating shaft and the portion that does not rotate even during use;
the sensor unit has a sensor cover that is fastened to and supported by the end section of the outer ring of the rolling bearing that is on the distal end side of the second rotating shaft; and
the first characteristic-changing member and the second characteristic-changing member are arranged in a space inside the sensor cover.

6. The torque measurement device-equipped rotation transmission apparatus according to claim 5 , wherein a seal device is located between a space where plural rolling bodies of the rolling bearing are located and the space inside the sensor cover, and is a partition between these spaces.

7. The torque measurement device-equipped rotation transmission apparatus according to claim 1 , wherein the second rotating shaft is rotatably supported with respect to the portion that does not rotate even during use by a rolling bearing that is located between a portion of the outer-circumferential surface of the second rotating shaft that is near the distal end with respect to the first rotating shaft and the portion that does not rotate during use; and the second characteristic-changing member is fitted and fastened around the outside of an end section near the distal end of the second rotating shaft of the inner ring of the rolling bearing that is fastened around the outside of a portion near the distal end of the second rotating shaft.

8. The torque measurement device-equipped rotation transmission apparatus according to claim 7 , wherein the second detected section of the second characteristic-changing member and at least one end section in the axial direction of the first detected section of the first characteristic-changing member are arranged on the outer-diameter side of the distal end of the second rotating shaft or another component that is fastened around the outside of that distal end in a position that overlaps in the radial direction the distal end of the second rotating shaft or the other component.

Assignees

• Nsk Ltd

Inventors

• Saito Tomoharu
• Matsuda Yasuyuki
• Gunji Daisuke
• Hikida Masafumi
• Tanaka Kazutaka
• Ueda Tohru
• Kaneko Yuka
• Takehara Tetsu
• Yoshioka Hiroyasu

Classifications

• G01L3/101

  involving magnetic or electromagnetic means · CPC title

• G01L3/104 Primary

  involving permanent magnets · CPC title

• G01L25/003

  for measuring torque · CPC title

• G01L3/109

  involving measuring phase difference of two signals or pulse trains · CPC title