CN108326802A - A kind of electric tool - Google Patents
A kind of electric tool Download PDFInfo
- Publication number
- CN108326802A CN108326802A CN201810303236.0A CN201810303236A CN108326802A CN 108326802 A CN108326802 A CN 108326802A CN 201810303236 A CN201810303236 A CN 201810303236A CN 108326802 A CN108326802 A CN 108326802A
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- Prior art keywords
- current value
- motor
- max
- electric tool
- control unit
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- 230000005540 biological transmission Effects 0.000 claims abstract description 3
- 238000001514 detection method Methods 0.000 claims description 19
- 230000005611 electricity Effects 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 3
- 230000000737 periodic effect Effects 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 20
- 230000007423 decrease Effects 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- 230000007850 degeneration Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000001595 flow curve Methods 0.000 description 1
- 238000012417 linear regression Methods 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D17/00—Details of, or accessories for, portable power-driven percussive tools
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D11/00—Portable percussive tools with electromotor or other motor drive
- B25D11/06—Means for driving the impulse member
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D16/00—Portable percussive machines with superimposed rotation, the rotational movement of the output shaft of a motor being modified to generate axial impacts on the tool bit
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
The invention discloses a kind of electric tools, motor, transmission device, output shaft, control unit including shell, in shell and switch, motor is rotated by actuator drives output shaft, control unit controls motor operation according on off state, control unit includes current detecting unit, storage unit and judging unit, current detecting unit is for detecting real time motor current value I, and storage unit is for storing maximum current value Imax；When motor rotates backward, when judging unit judgement current motor current value I is less than or equal to storage maximum current value ImaxK times when, control unit cuts off current of electric, and the value range of the K is 0.3 to 0.7.Technical solution provided by the invention can realize that tool inverts automatic stop function, prevent bolts and nuts from completely disengaging the risk fallen.
Description
[technical field]
The present invention relates to a kind of electric tool, more particularly to it is a kind of can autostop electric tool.
[background technology]
Currently, common electric tool, such as screwdriver, impact wrench are all to drive output shaft rotation by spiral shell by motor
The fasteners such as nail, bolt are tightened or removal.When removing fasteners, since electric tool rotating speed is very high, within a very short time, so that it may
By fastener removal, to be easy to cause the problem of fastener falls off after removal, to solve this problem, Chinese invention patent is public
Accuse No. CN104656549B, it is proposed that a kind of technical solution, by detect motor current value, by motor current value with it is preset
Threshold value comparison changes motor speed or shutdown if being less than or equal to predetermined threshold value.But in practical situations, with electronic
After tool usage time is elongated, different degrees of degeneration can occur for the permanent magnet of motor, so that being driven in identical electric current
Under, the output torque of motor declines, if using fixed predetermined current threshold as the standard judged is shut down, in electric tool
After long-time use, it may appear that the phenomenon that screw is excessively loosened.
[invention content]
In view of the deficiencies of the prior art, the purpose of the present invention is to provide one kind can solve to change in motor running parameter
In the case of can realize the electric tool of automatic stop.To achieve the above object, the technical solution adopted by the present invention is：A kind of electronic work
Tool, including：Shell, the motor in shell, transmission device, output shaft, control unit and switch, electric motor drives
Output shaft is driven to do positive and reverse rotation motion, and control unit controls motor operation, control unit packet according on off state
Detection unit, storage unit and judging unit are included, detection unit is used to detect the real-time current value I of motor, and single by storing
Member storage maximum current value Imax；When motor rotates backward, it is less than or equal in judging unit judgement current motor current value I
Store maximum current value ImaxK times when, control unit cuts off current of electric, and the value range of K is 0.3 to 0.7.
Further, current detecting unit obtains electricity by the current detection circuit being made of resistive element and filter circuit
Electromechanical flow valuve I.
Further, when judging unit judgement current motor current value I is less than or equal to storage maximum current value ImaxK times,
And after preset duration T, control unit cuts off current of electric, and the value range of preset duration T is 30ms to 300ms.
Further, detection unit obtains motor current value I by periodic samples, and the sampling period is less than preset duration
T。
Further, filter circuit is first-order lag filter circuit.
Further, maximum current value ImaxAcquisition methods be：After motor reversal starts, storage unit will detect
First current value storage that unit detects is used as maximum current value Imax。
Further, maximum current value ImaxAcquisition methods further include：Control unit is periodically by memory cell
The maximum current value I of storagemaxIt is compared with the current value I detected in real time, if the maximum current value of memory cell storage
ImaxMore than or equal to the current value I detected in real time, then maximum current value ImaxMotor current value that is constant, otherwise will newly detecting
I is set as maximum current value Imax。
Further, motor reversal starts the time as preset fixed value.
Further, electric tool is brushless impact wrench.
Compared with prior art, the present invention has the advantages that：Decline in cell voltage or because permanent magnet degeneration is made
When declining at motor working performance, it still may be implemented accurately to invert autostop, prevent fastener from falling off.
[description of the drawings]
Specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings:
Fig. 1 is electric tool schematic diagram of the present invention；
Fig. 2 is electric tool circuit logic diagram of the present invention；
Current curve schematic diagram when Fig. 3 is electric tool reversion removing fasteners of the present invention；
Fig. 4 be electric tool of the present invention in the unloaded state, current curve schematic diagram when reversion；
Fig. 5 is electric tool circuit diagram of the present invention；
Fig. 6-1 is that electric tool of the present invention band when K is 0.3 carries current curve diagram；
Fig. 6-2 is electric tool of the present invention zero load current curve diagram when K is 0.3；
Fig. 6-3 is that electric tool of the present invention band when K is 0.5 carries current curve diagram；
Fig. 6-4 is electric tool of the present invention zero load current curve diagram when K is 0.5；
Fig. 6-5 is that electric tool of the present invention band when K is 0.7 carries current curve diagram；
Fig. 6-6 is electric tool of the present invention zero load current curve diagram when K is 0.7；
[specific implementation mode]
Below in conjunction with attached drawing, specific description is done to embodiments of the present invention.
Electric tool and circuit logic diagram shown in refer to the attached drawing 1 and 2, the electric tool, such as impact wrench, it is main to wrap
Shell 1, the motor (not shown) in shell are included, is rotated by actuator drives output shaft 2 by motor, in this reality
The motor used in mode is applied as brushless motor, the battery pack 3 as power supply being connect with tool body, control electric motor starting/
The main switch SW1 and control unit MCU4 of stopping, control unit MCU4 include：Detection unit, judging unit and storage unit, control
Unit MCU4 processed receives the input signal of main switch SW1, reversing switch SW2 and current detection circuit 5, and control motor is held accordingly
The corresponding action of row.
Current curve schematic diagram shown in refer to the attached drawing 3, when impact wrench is switched to instead by user's operation reversing switch SW2
When rotary-die type, work head and the fastener at 2 end of output shaft contradict, and press main switch SW1, electric motor starting, motor starting time is
One predetermined fixed value, starting the time in present embodiment is set as 100ms.In startup stage, current of electric I quickly becomes larger,
Current of electric I has reached maximum value when startup stage completes.When completing startup stage, i.e. after main switch SW1 triggers 100ms,
Control unit MCU4 starts to acquire motor current value I by current detection circuit 5, and the storage unit of control unit MCU4 is by first
The motor current value I of secondary acquisition is as maximum current value ImaxStorage.The detection unit of control unit MCU4 is in real time from current detecting
The current value I and storage unit that the judging unit of the acquisition of circuit 5 motor current value I, control unit MCU4 will then detect in real time
Interior maximum current value ImaxIt is compared, if the current value I detected in real time is less than maximum current value ImaxK times when, that is, stop
Machine Rule of judgment is I<K*Imax, then control unit MCU4 send out the signal of cut-out motor power, motor drive current I becomes zero,
Realize the reversion autostop of impact wrench.Shut down judgment value cannot it is too small also cannot be excessive, if shut down Rule of judgment be
Less than maximum current value Imax0.1 times when, since the no-load current value of the current value and impact wrench is close, can not realize
Prevent the purpose of loosened fastener, but if shut down Rule of judgment it is excessive if cause fastener to can not be successfully separation purpose.
Attached drawing 6-1 is when K is 0.3, and current curve diagram when electric tool band carries, electric current starts to increase after motor reversal starts, right
The impact of fastener cycle causes current waveform to be in cyclically-varying, and after fastener unclamps, electric current declines, in real-time current
When value I reaches 0.3 times of maximum current value, current interruptions become zero, and shut down.Fig. 6-2 be K at 0.3, when unloaded, motor is anti-
Current curve diagram when turning is shut down equally when real-time current value I reaches 0.3 times of maximum current value.Fig. 6-3 is K 0.5
When, current curve diagram when electric tool band carries, current curve and K are essentially identical when being 0.3, reach in real-time current value I
At 0.5 times of maximum current value, current interruptions become zero, and shut down.Fig. 6-4 is K at 0.5, when unloaded, electricity when motor reversal
Flow curve figure is shut down equally when real-time current value I reaches 0.5 times of maximum current value.Fig. 6-5 be K at 0.7, electronic work
Current curve diagram when tool band carries, current curve and K are essentially identical when being 0.3, reach maximum current value in real-time current value I
0.7 times when, current interruptions become zero, shut down.Fig. 6-6 is K at 0.7, when unloaded, current curve diagram when motor reversal,
Equally when real-time current value I reaches 0.7 times of maximum current value, shut down.Think that shutting down Rule of judgment is set to through test of many times
Maximum current value Imax0.3 to 0.7 times be advisable.
In order to prevent because the reasons real-time current value I that cause detection unit to detect such as current of electric shake are too small, cause
Erroneous judgement is shut down, in other embodiment：It is that real-time current value I is constantly less than maximum current value I to shut down Rule of judgmentmax
0.4 times, and the duration be no less than 30ms, the duration can not ether is short also cannot be too long, the duration it is too short cannot
It prevents from judging by accident, duration long then easy delay downtime causes loosened fastener to fall, the duration takes 30ms extremely
300ms is advisable, and control unit MCU4 sends out the signal of cut-out motor power, tool down.
Further, since it is predetermined fixed value to start the time, but due to actual condition complexity, after startup stage,
Motor current value I may and not up to maximum value, or be likely to occur motor current value in assault phase and tied more than startup stage
The case where current value when beam, in other embodiment, detection unit at the end of the startup stage periodically, i.e., every
50ms acquires motor current value I, and the maximum that collected current value I and memory cell are stored up from current detection circuit 5
Current value ImaxCompare, if the maximum current value I of memory cell storagemaxIt, then will be original less than newest collected current value I
The current value being stored in storage unit replaces with newest collected current value I, as maximum current value Imax。
Motor output torque T=Kt* I, wherein KtRelated to motor characteristic for moment coefficient, I is motor current value, generally
Think KtFor constant, after motor model is fixed, it can be calculated by current value I and obtain its output torque.But because physical environment,
The permanent magnet magnetism of the influence of the factors such as machine natural wastage, brushless motor can die down, and cause motor characteristic to decline, moment coefficient
KtBecome smaller, therefore in moment coefficient KtAfter becoming smaller, identical load is faced, motor output current I will become larger.If using existing
There are the fixed current threshold decision mode in technology, actual downtime that will delay, to there is fastener excessively to unclamp
The risk fallen, using the technical solution in present embodiment, moment coefficient KtAfter becoming smaller, in the case where loading constant, storage
The maximum current value I of element memory storagemaxIt can become larger, actual shutdown Rule of judgment --- maximum current value ImaxK times, K's
Value range is 0.3 to 0.7, and also can be proportional become larger, is identical before actual shutdown moment and motor characteristic decline.
The technical solution in present embodiment is used, the situation of change of actual loading can be more accurately monitored, eliminates motor characteristic
Variation adverse effect caused by tool.
Current curve schematic diagram shown in refer to the attached drawing 4, in the unloaded state i.e. the work head of 2 end of output shaft not with
When fastener contacts, main switch SW1 startups are triggered under reversing mode.Motor starting time remains as 100ms, motor current value
I becomes larger rapidly in startup stage, and motor current value I reaches maximum value after startup stage, but because work head end is not present
Actual loading, therefore current of electric I starts to be gradually reduced, final current value I can stablize at a lower level value, i.e., electric
Machine no-load current, usual empty load of motor current value are 0.1 times to 0.3 times of motor maximum current value.In the unloaded state, it controls
The detection unit of unit MCU4 started to acquire motor current value I after startup stage, and storage unit will collect for the first time
Motor current value I as maximum current value ImaxStorage, when judging unit judgement motor drive current value I drops to maximum electricity
Flow valuve Imax0.4 times when, control unit MCU4 send out cut-out motor power signal, i.e. control unit MCU4 is in light condition
Under control logic it is identical as under the loose screw pattern of reversion, when zero load reversion, impact wrench also can autostop.
Circuit diagram shown in refer to the attached drawing 5, due in actual condition, motor drive current be there are many burrs and
Shake, in order to preferably acquire motor current value I, current detection circuit 5 is the first-order lag filter being made of resistance 6, capacitance 7
Wave circuit and resistance R1 are constituted, and can eliminate the burr of motor drive current by first-order lag filter circuit and part is shaken,
To keep the current signal that detection unit obtains smoother.In other embodiment, other circuits can also be used to electricity
Electromechanical flow valuve I carries out sampling filter, such as averaging circuit, sliding-window filtering circuit, linear regression circuit etc..
The invention is not limited in any way for embodiment of above, all to be obtained by the way of equivalent substitution or equivalent transformation
The technical solution obtained, all falls in protection scope of the present invention.
Claims (9)
1. a kind of electric tool, including shell, the motor in shell, transmission device, output shaft, control unit and switch,
Electric motor drives drive output shaft to do positive and reverse rotation motion, and control unit controls motor according on off state
Operation, it is characterised in that：
Described control unit includes detection unit, storage unit and judging unit, and the detection unit is used to detect the reality of motor
When current value I, and pass through storage unit and store maximum current value Imax；
When motor rotates backward, it is less than or equal to the maximum in storage unit in judging unit judgement current motor current value I
Current value ImaxK times when, control unit cuts off current of electric, and the value range of the K is 0.3 to 0.7.
2. electric tool according to claim 1, it is characterised in that：The current detecting unit by by resistive element and
The current detection circuit of filter circuit composition obtains motor current value I.
3. electric tool according to claim 2, it is characterised in that：When judging unit judgement current motor current value I is small
In or equal to storage maximum current value ImaxK times, and after preset duration T, control unit cuts off current of electric, described pre-
If the value range of duration T is 30ms to 300ms.
4. electric tool according to claim 3, it is characterised in that：The detection unit obtains electricity by periodic samples
Electromechanical flow valuve I, sampling period are less than the preset duration T.
5. electric tool according to claim 4, it is characterised in that：The filter circuit is first-order lag filter circuit.
6. electric tool according to claim 1, it is characterised in that：The maximum current value ImaxAcquisition methods be：Electricity
After machine reversion starts, first current value storage that storage unit detects detection unit is used as maximum current value Imax。
7. electric tool according to claim 6, it is characterised in that：The maximum current value ImaxAcquisition methods into one
Step includes：The maximum current value I that control unit periodically stores up memory cellmaxWith the current value I that detects in real time into
Row compares, if the maximum current value I of memory cell storagemaxMore than or equal to the current value I detected in real time, then maximum current
Value ImaxIt is constant, the motor current value I newly detected is otherwise set as maximum current value Imax。
8. electric tool according to claim 7, it is characterised in that：Motor reversal starts the time as preset fixed value.
9. electric tool according to claim 8, it is characterised in that：The electric tool is brushless impact wrench.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810303236.0A CN108326802A (en) | 2018-04-07 | 2018-04-07 | A kind of electric tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810303236.0A CN108326802A (en) | 2018-04-07 | 2018-04-07 | A kind of electric tool |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108326802A true CN108326802A (en) | 2018-07-27 |
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ID=62932802
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810303236.0A Pending CN108326802A (en) | 2018-04-07 | 2018-04-07 | A kind of electric tool |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108326802A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110208688A (en) * | 2019-05-09 | 2019-09-06 | 石家庄科林电气股份有限公司 | A kind of failure pre-judging method of breaker energy storage motor |
| CN114453620A (en) * | 2020-11-09 | 2022-05-10 | 南京泉峰科技有限公司 | Intelligent electric tool and control method thereof |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11138459A (en) * | 1997-11-05 | 1999-05-25 | Nissan Motor Co Ltd | Impact screw fastening method and its device |
| CN101811297A (en) * | 2009-02-25 | 2010-08-25 | 罗伯特·博世有限公司 | Electric tool |
| CN104520072A (en) * | 2012-03-13 | 2015-04-15 | 日立工机株式会社 | Impact tool |
| CN204651901U (en) * | 2015-04-08 | 2015-09-16 | 江苏东成机电工具有限公司 | A kind of electric tool |
| CN105522520A (en) * | 2014-10-20 | 2016-04-27 | 株式会社牧田 | Rotation impact tool |
| CN105856140A (en) * | 2014-09-02 | 2016-08-17 | 苏州宝时得电动工具有限公司 | Control method and system of electric tool and electric tool |
| CN107685315A (en) * | 2016-08-05 | 2018-02-13 | 株式会社牧田 | Electric tool |
| CN208697343U (en) * | 2018-04-07 | 2019-04-05 | 江苏东成机电工具有限公司 | A kind of electric tool |
-
2018
- 2018-04-07 CN CN201810303236.0A patent/CN108326802A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11138459A (en) * | 1997-11-05 | 1999-05-25 | Nissan Motor Co Ltd | Impact screw fastening method and its device |
| CN101811297A (en) * | 2009-02-25 | 2010-08-25 | 罗伯特·博世有限公司 | Electric tool |
| CN104520072A (en) * | 2012-03-13 | 2015-04-15 | 日立工机株式会社 | Impact tool |
| CN105856140A (en) * | 2014-09-02 | 2016-08-17 | 苏州宝时得电动工具有限公司 | Control method and system of electric tool and electric tool |
| CN105522520A (en) * | 2014-10-20 | 2016-04-27 | 株式会社牧田 | Rotation impact tool |
| CN204651901U (en) * | 2015-04-08 | 2015-09-16 | 江苏东成机电工具有限公司 | A kind of electric tool |
| CN107685315A (en) * | 2016-08-05 | 2018-02-13 | 株式会社牧田 | Electric tool |
| CN208697343U (en) * | 2018-04-07 | 2019-04-05 | 江苏东成机电工具有限公司 | A kind of electric tool |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110208688A (en) * | 2019-05-09 | 2019-09-06 | 石家庄科林电气股份有限公司 | A kind of failure pre-judging method of breaker energy storage motor |
| CN114453620A (en) * | 2020-11-09 | 2022-05-10 | 南京泉峰科技有限公司 | Intelligent electric tool and control method thereof |
| CN114453620B (en) * | 2020-11-09 | 2024-01-05 | 南京泉峰科技有限公司 | Intelligent electric tool and control method thereof |
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