Dust collecting system

1. A dust collecting system including a power tool configured to perform a processing operation on a workpiece by driving a tool accessory and a dust collector configured to collect dust generated by the processing operation, wherein:

the power tool comprises:

a first motor; and

a driving mechanism configured to drive the tool accessory by power of the first motor;

the dust collector comprises:

a second motor; and

a fan configured to be rotationally driven by the second motor to generate air flow for collecting the dust;

the dust collecting system comprises a first control device configured to change a rotation speed of the second motor according to a driving time of the first motor from a start of driving of the first motor; and

the first control device is configured to increase the rotation speed of the second motor as the driving time increases.

2. The dust collecting system as defined in claim 1 , further comprising a time-measuring device configured to measure the driving time.

3. The dust collecting system as defined in claim 1 , wherein the first control device is configured to drive the second motor at a first rotation speed until the driving time reaches a specified time from the start of driving of the first motor and to change the rotation speed of the second motor to a second rotation speed when the driving time reaches the specified time, the second rotation speed being lower than the first rotation speed.

4. The dust collecting system as defined in claim 1 , further comprising:

a time-measuring device configured to measure the driving time; and

a memory that stores a correspondence relationship between (i) a length of the driving time and (ii) the rotation speed of the second motor;

wherein the first control device is configured to set the rotation speed of the second motor according to (i) the length of the driving time and (ii) the correspondence relationship.

5. A dust collecting system including a power tool configured to perform a processing operation on a workpiece by driving a tool accessory and a dust collector configured to collect dust generated by the processing operation, wherein:

the power tool comprises:

a first motor; and

a driving mechanism configured to drive the tool accessory by power of the first motor;

the dust collector comprises:

a second motor; and

a fan configured to be rotationally driven by the second motor to generate air flow for collecting the dust;

the dust collecting system comprises a first control device configured to change a rotation speed of the second motor according to a driving time of the first motor from a start of driving of the first motor;

the first control device is configured to change the rotation speed of the second motor to zero when a standby time elapses after driving of the first motor is stopped, the standby time being set according to the driving time of the first motor; and

the first control device is configured to set the standby time to be longer as the driving time increases.

6. A dust collecting system including a power tool configured to perform a processing operation on a workpiece by driving a tool accessory and a dust collector configured to collect dust generated by the processing operation, wherein:

the power tool comprises:

a first motor;

a driving mechanism configured to drive the tool accessory by power of the first motor; and

a load-detecting device configured to detect load on the tool accessory;

the dust collector comprises:

a second motor; and

a fan configured to be rotationally driven by the second motor to generate air flow for collecting dust; and

the dust collecting system comprises a first control device configured to change a rotation speed of the second motor according to the load.

7. The dust collecting system as defined in claim 6 , wherein the first control device is configured to increase the rotation speed of the second motor as the load increases.

8. The dust collecting system as defined in claim 6 , wherein:

the load-detecting device is configured to detect at least vibration of the power tool as the load, and

the first control device is configured to change the rotation speed of the second motor according to the vibration.

9. The dust collecting system as defined in claim 8 , wherein the first control device is configured to increase the rotation speed of the second motor as the vibration increases.

10. The dust collecting system as defined in claim 8 , wherein the power tool includes a body housing that houses the first motor, the driving mechanism and

the load-detecting device.

11. The dust collecting system as defined in claim 6 , further comprising:

a second control device configured to control driving of the first motor, wherein:

the second control device is configured to control a rotation speed of the first motor not to exceed a specified upper-limit speed, in a case where the load is not more than a specified threshold,

the second control device is configured to allow the rotation speed of the first motor to exceed the upper-limit speed, in a case where the load exceeds the threshold, and

the first control device is configured to change the rotation speed of the second motor in conjunction with control of the first motor by the second control device.

12. The dust collecting system as defined in claim 11 , wherein:

the first control device is in the dust collector, and

the second control device is in the power tool.

13. The dust collecting system as defined in claim 6 , wherein the first control device is configured to change the rotation speed of the second motor according to a rotation speed of the first motor and a driving time of the first motor from a start of driving of the first motor.

14. The dust collecting system as defined in claim 13 , wherein the first control device is configured to change the rotation speed of the second motor to zero when a standby time elapses after driving of the first motor is stopped, the standby time being set according to the driving time.