Gear device and robot

{
  "publication_number": "US11781632B2",
  "country": "US",
  "kind": "B2",
  "title": "Gear device and robot",
  "abstract": "A gear device includes an internal gear, an external gear having flexibility, a wave generator, a cross roller bearing, and a first seal and a second seal. The external gear includes a cylindrical body section including a first end portion, with which the wave generator is in contact, and a second end portion on the opposite side of the first end portion, external teeth provided on the outer circumferential surface of the first end portion, an annular diaphragm section provided on the outer side of the second end portion, and a boss section provided on the outer side of the diaphragm section. The first seal is sandwiched between the boss section and an outer ring of the cross roller bearing. The second seal includes a proximal end fixed to the outer ring and a distal end in contact with the outer circumferential surface of an inner ring.",
  "claims": [
    "1. A gear device comprising: an internal gear; an external gear having flexibility and configured to partially mesh with the internal gear and rotate around a rotation axis relatively to the internal gear; a wave generator configured to come into contact with an inner circumferential surface of the external gear and move a meshing position of the internal gear and the external gear in a circumferential direction around the rotation axis; a cross roller bearing including an outer ring and an inner ring; and a first seal and a second seal fixed to the outer ring, wherein the external gear includes: a cylindrical body section including a first end portion, with which the wave generator is in contact, and a second end portion on an opposite side of the first end portion; external teeth provided on an outer circumferential surface of the first end portion; an annular diaphragm section provided on an outer side of the second end portion; and a boss section provided on an outer side of the diaphragm section, the first seal is sandwiched between the boss section and the outer ring, and the second seal includes a proximal end and a distal end, the proximal end is fixed to the outer ring, wherein a gap is formed between an inner circumferential surface of the outer ring and an outer circumferential surface of the inner ring, wherein the second seal is held to locate the distal end of the second seal so that the distal end penetrates into the gap and is in contact with the outer circumferential surface of the inner ring.",
    "2. The gear device according to claim 1, wherein the first seal and the second seal are integrated.",
    "3. The gear device according to claim 1, wherein the first seal and the second seal are separated.",
    "4. The gear device according to claim 1, wherein a contact direction of the distal end of the second seal with the outer circumferential surface is a direction forming an angle within the range of −45° to +45° with respect to a normal of the outer circumferential surface.",
    "5. The gear device according to claim 1, further comprising a third seal including a proximal end and a distal end, wherein the proximal end of the third seal is fixed to the outer ring, and the distal end of the third seal is in contact with a surface of the inner ring opposed to the diaphragm section.",
    "6. A robot comprising: a first member; a second member configured to turn with respect to the first member; the gear device according to claim 1 configured to transmit a driving force for turning the second member relatively to the first member; and a driving source configured to output the driving force toward the gear device."
  ],
  "description_excerpt": "The present application is based on, and claims priority from JP Application Serial Number 2020-136976, filed Aug. 14, 2020, the disclosure of which is hereby incorporated by reference herein in its entirety.\n\nThe present disclosure relates to a gear device and a robot.\n\nIn a robot including a robot arm, for example, a joint section of the robot arm is driven by a motor. In general, rotation of the motor is decelerated via a speed reducer and transmitted to an arm. As such a speed reducer, for example, a wave gear device described in JP-A-2007-16838 (Patent Literature 1) has been known.\n\nThe wave gear device described in Patent Literature 1 includes an annular internal gear on which internal teeth are formed, a flexible external gear on which external teeth meshing with the internal teeth are formed, and a wave generator disposed on the inner side of the external gear. A cross roller bearing attached with a one-side seal or both-side seals is disposed in an outer side position in the radial direction of the internal gear. By providing such a seal member, it is unnecessary to provide oil seals in other members.\n\nSealability of the cross roller bearing attached with the seal described in Patent Literature 1 is sometimes set low not to prevent rotation of the cross roller bearing. Accordingly, grease easily moves between a gap between the external gear and the cross roller bearing and the inside of the cross roller bearing. Then, the grease tends to move to only a part in a range to which the grease should be spread which makes the life of the wave gear device shorten.",
  "cpc": [
    "F16H 49/001",
    "B25J 19/0062",
    "B25J 9/042",
    "B25J 9/102",
    "B25J 9/1025",
    "B25J 9/126",
    "F16C 33/76",
    "F16H 2049/003"
  ],
  "ipc": [
    "B25J 9/10",
    "F16H 49/00"
  ],
  "assignees": [
    "Seiko Epson Corp"
  ],
  "inventors": [
    "Yuya KATAOKA"
  ],
  "filing_date": "2021-08-12",
  "publication_date": "2023-10-10",
  "grant_date": "2023-10-10",
  "priority_date": "2020-08-14",
  "application_number": "US-202117400120-A",
  "family_id": "80223995",
  "cited_by_count": 0,
  "citations": [
    "US3523488A",
    "JP2007016838A",
    "US20090233750A1",
    "US20150300475A1",
    "US20170370457A1",
    "US20200003288A1",
    "JP2020509311A",
    "WO2018189798A1",
    "US20200072338A1"
  ]
}