CN2069181U

CN2069181U - Contactless and stepless speed regulator for electric tool

Info

Publication number: CN2069181U
Application number: CN 90212190
Authority: CN
Inventors: 邵正贤
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-05-02
Filing date: 1990-05-02
Publication date: 1991-01-09

Abstract

The utility model relates to a non contact stepless speed regulating switch which is used for an electric tool and can interchange an installing dimension with an original switch. The non contact stepless speed regulating switch which is used for an electric tool and can interchange an installing dimension with an original switch is made by a displacement sensor and a controlled silicon triggering synchronous circuit by adopting magnetic-sensing displacement sensing technique. The non contact stepless speed regulating switch which is used for an electric tool and can interchange an installing dimension with an original switch is characterized in that a permanent magnet, a Hall element, and an operational amplifier form a magnetic-sensing displacement sensor, and the rotary speed of the motor of the electric tool is regulated in a non-electrical contact mode. The deathful defect existing in the electronic speed regulating switch of the electric tool which is made by adopting a potentiometer due to that the life of the potentiometer is limited and the contact of sliding contact points is unreliable is overcome. The utility model has simple structure and cheap manufacturing cost.

Description

Contactless and stepless speed regulator for electric tool

The utility model is a kind of contactless stepless speed regulation switch, can be used for each type electric tool, reaches non-purpose of regulating motor speed in electrical contact.

Through consulting relevant document and data, do not see the report that this respect is arranged both at home and abroad.The electronic stepless speed regulation switch that the contact is arranged that this contactless electronic stepless speed regulation switch performance obviously is better than being adopted on the external electric tool.

All kinds of homemade electric tool of existing market mostly is single speed, and is extremely not convenient in some use occasions.The electric tool of import has (as: 10VC of Hitachi, the D10V1 electric hand drill etc.) that adopt electronic stepless speed regulation.Its structure is as commercially available lamp dimmer, and the angle of flow that changes bidirectional triode thyristor with carbon film potentioneter comes speed governing.

And well-known, the life-span of carbon film potentioneter is limited, very easily makes speed governing malfunctioning because of sliding contact is unreliable.Electric tool often uses in various complexity, abominable workplace, and therefore adopting has the potentiometer of contact to come the electronic switch of speed governing to have weak spot unsurmountable on the structure, that cause.The import electric tool of commercially available employing potentiometer speed governing reflects generally that according to sale shop, user, electric tool maintenace point the potentiometer regular meeting of speed-regulating switch damages.At present domestic this electron-like speed-regulating switch that a few producer imitation Japan such as Qingdao the 4th instrument plant are arranged.

The purpose of this utility model is to solve the disadvantage that electric tool has the contact speed governing, electronic speed-regulating switch is reached under the normal use never damage.

Core structure of the present utility model is to adopt the magnetosensitive displacement transducer to realize the electricity conversion.Edge lastblock permanent magnet on switch handle end, when the Push switch handle, magnet just and then moves together.On fixing position a Hall element that can detect magnetic field is arranged, along with shifting near of magnet, the Hall element output potential increases.After amplifier amplifies, obtain a voltage signal that moves into ratio with handle position.So just constituted one contactless " electronic potentiometer ", cooperated by trigger synchronous circuits again, removed to control the silicon controlled angle of flow.Handle so press...with one's finger on the moving switch, the motor of electric tool just can be from stopping the stepless speed of turning up full blast.

On the electric tool, the volume that switch is installed is limited, requires the essential miniaturization of electronic speed-regulating switch.Present homemade electric tool is the unified design in the whole nation mostly, and this just requires electronic speed-regulating switch and present standardized mechanical switch can exchange on contour structures and installation dimension.Electronic speed-regulating switch of the present utility model has adopted unique electronic circuit, with minimum element, the compactest geometry, has accomplished that energy and general switch with mechanical contact exchange, and has had the ON state lock function equally.

Fig. 1 is an electronic circuit of the present utility model.

Contactless electron potentiometer and triggering, synchrolock are combined as a whole dexterously.As silicon controlled main rectifier SCR2 not during conducting, synchronizing voltage (being civil power) is added in full-bridge two ac input ends of being made up of D1～D4, the full-bridge positive and negative terminal obtains 180 ° of half-sinusoid voltages on the same direction, through R1, R2 step-down, provide synchronous direct voltage behind the D5 slicing to Hall element H and operational amplifier A.The operational amplifier A output voltage converts constant-current source to through triode T capacitor C is charged.In case the voltage on the capacitor C rises to the conducting voltage of bidirectional diode D6, small thyristor SCR1 conducting so the control utmost point of silicon controlled main rectifier SCR2 and anode form path, forces silicon controlled main rectifier SCR2 conducting.Magnet is near more from Hall element, and the constant-current source electric current is big more, and the capacitor C charging interval is short more, and the angle of flow of silicon controlled main rectifier SCR2 is big more, thereby motor speed is fast more.

Fig. 2, Fig. 3 are the utility model structure charts.

Permanent magnet 1 is placed in handle rear end among Fig. 2, Fig. 3, and Hall element 2 and electronic circuit board place the below of permanent magnet.When finger depress switch handle, magnet moves down with handle, near Hall element, Hall element detect magnet near the time magnetic flux density variation, the magnet displacement signal of Hall element output is through operational amplifier, the synchronous trigger circuit control silicon controlled angle of flow, so that can make things convenient for and contactlessly control rotating speed of motor.

Fig. 2 is used for the new-type shell electric tool of moulding, and Fig. 3 is used for old-fashioned imitative Soviet Union metal-back electric tool.

Figure, two kinds of structures shown in Figure 3, electronic section all is enclosed in the plastic casing, and is both safe and reliable, can adapt to various electric tools again.

Electronic circuit of the present utility model can provide very big trigger current, and the capacity of silicon controlled main rectifier SCR2 is not limited.In the same way, but select the chamber silicon of big electric current for use, just can be used for the occasion of more high-power pressure regulation and automatically in the Control and Feedback system.

I had installed this switch once before 5 years on personal 6mm electric hand drill, stood various tests, and when the perforating, careless drill bit is killed to object as electric drill sometimes, and at this moment current of electric increases to starting current rapidly, and switch is still safe and sound.Up to still very normal work at present.

Contactless stepless speed regulation switch of the present utility model stands from-20 ℃ to+70 ℃ the temperature test, but in this temperature range operate as normal all, the operating position drift value of switch handle is very little.

The cost of contactless stepless speed regulation switch of the present utility model is cheap, about 15 yuans of the fee of material of producing in batches, be that electric tool institute is receptible, if can partly replace traditional switch with mechanical contact, just can save the noble metal silver that the contact is made in a large amount of being used to for country.

Contactless stepless speed regulation switch of the present utility model is owing to be better than having the stepless speed regulation switch of contact abroad on the performance, adopted as the electric tool of China, this class electronic product of electric tool that also can be China increase advantage that squeezes into the international market.

Claims

1, a kind of contactless stepless speed regulation switch that is used for each type electric tool is made by displacement transducer, controllable silicon trigger synchronous circuits, it is characterized in that constituting the magnetosensitive displacement transducer with permanent magnet, Hall element and operational amplifier; The non-angle of flow of controlling controlled extension in electrical contact.

2, by claim 1 a described contactless stepless speed regulation switch, it is characterized in that permanent magnet is placed on switch knob the inner.