{
  "$type": "site.standard.document",
  "description": "A speed-changing device includes a motor (1), a reduction gear train (2) that reduces a rotation speed of the motor (1) in accordance with a speed reduction ratio and transmits the rotation at the reduced speed, and a speed reduction ratio switching unit (20) that switches the speed reduction…",
  "path": "/patents/990480",
  "publishedAt": "2013-05-22T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "B25F5/001",
    "PANASONIC CORP [JP]"
  ],
  "textContent": "A speed-changing device includes a motor (1), a reduction gear train (2) that reduces a rotation speed of the motor (1) in accordance with a speed reduction ratio and transmits the rotation at the reduced speed, and a speed reduction ratio switching unit (20) that switches the speed reduction ratio. The speed reduction ratio switching unit (20) includes an actuator (6) that switches the speed reduction ratio, a controller (60) that controls the actuator (6), and a drive state detector (68) that detects an index value representing load torque applied to the motor (1). The controller (60) activates the actuator (6) when the index value exceeds a first threshold value (L1) and activates the actuator (6) when the index value fluctuates between the first threshold (L1) and a second threshold (L2) thereby forming an undulated pattern (L3) that satisfies a predetermined condition.",
  "title": "Speed-changing device"
}