CN101038706A

CN101038706A - Drive apparatus for pendulum

Info

Publication number: CN101038706A
Application number: CN 200710072007
Authority: CN
Inventors: 李前程; 赵彤; 陈奇; 李翼龙
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2007-04-09
Filing date: 2007-04-09
Publication date: 2007-09-19

Abstract

The invention discloses a driving device of a pendulum, which is maily used for driving a foucault pendulum. The driving device comprises a power source, an exciter driving circuit, a frame and a pendulum, wherein a hollow pendulum shaft is mounted on the frame, a magnet is fixed on a lower end of the pendulum shaft and is provided with a through hole which is larger at an upper end and smaller at a lower end in the centre, a pendulum rope is passed through the through hole and clamped in the through hole, a circular recess is provided at a lower end of an electric magnet, an armature is composed of a circular disc at an upper portion and a hollow column at a lower portion, the circular disc is mounted in the recess, the pendulum rope is passed through the armature and connected with a pendulum hammer at the lower end, a barrier and a spring is orderly mounted on the pendulum rope between the pendulum hammer and the armature, the spring is contact with a lower end of the armature, a laser indicator is fixed below the pendulum hammer, a dividing disk on which a photoelectric inductor is mounted at the centre is mounted below the pendulum hammer. The invention continuously excites the pendulum by the electric magnet, a driving direction is automatically and strictlys along a pendular direction of the pendulum, so as to reduce error, at the same time, the extraction of synchronization signals is more convenient by using the photoelectric inductor, thereby the invention is convenient to show and teach.

Description

A kind of drive unit of pendulum

Technical field

The present invention relates to a kind of drive unit, a kind of specifically device that adopts electromagnet to come pendulum is continued excitation.

Background technology

Foucault pendulum is a kind of single pendulum that is used for revolutions provably, and this pendulum can produce because of earth rotation slowly and move, but prerequisite is just can carry out undamped swing under the interference of no any external force except that gravity, thus the checking earth rotation.Carry out zero-decrement swing in order to make pendulum overcome air resistance, existing drive unit has has added the energy compensating device, and cost is very high, the realization in a vacuum that has, and cost is higher, and teaching demonstration is carried out in inconvenience in the laboratory.

Summary of the invention

The objective of the invention is to overcome the weak point that exists in the above-mentioned technology, a kind of compact conformation, drive unit reasonable in design are provided, make the swing that pendulum can be lasting and the direction of motion of indication pendulum clearly, be convenient to demonstrate and the drive unit of the pendulum of the usefulness of imparting knowledge to students.

In order to achieve the above object, the technical solution used in the present invention is: comprise power supply, the excitation driving circuit, frame and pendulum, it is characterized in that: installation shaft bearing on the frame, thrust magnetic bearing and guide bearing from top to bottom are housed respectively in it, hollow balance staff is loaded in the described two bearings, the electromagnet lead-in wire is through in the balance staff, the upper end links to each other with the excitation driving circuit with brush by collector ring, the lower end links to each other with the coil of the electromagnet inside that the balance staff lower end installs, the electromagnet center has up big and down small through hole, the pendulum rope passes described through hole and is stuck in the through hole, the electromagnet lower end has circular groove, armature is connected by the hollow cylinder of the disk on top and bottom and forms, disk is loaded in the groove, the pendulum that the pendulum rope passes armature and lower end links to each other, be installed with block and spring successively on the pendulum rope between pendulum and the armature, end in contact under spring and the armature, install laser designator under the pendulum, over against the pendulum below index plate is housed, photoelectric sensor is installed in center on it, and photoelectric sensor is linked to each other with the excitation driving circuit by lead.

Advantage of the present invention is:

Because the present invention has adopted the maglev type axial thrust bearing to come the gravity of balance wheel, rotary resistance is reduced greatly, and because ad hoc structure makes the strict automatically swaying direction along pendulum of the driving direction of electromagnet, reduced error, adopt photoelectric induction device simultaneously, greatly facilitated the extraction of synchronizing signal.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Embodiment

Below in conjunction with accompanying drawing embodiments of the invention are described in further detail.

As shown in Figure 1, power supply 1 of the present invention is connected to excitation driving circuit 2, and installation shaft bearing 20 on the frame 3 is equipped with thrust magnetic bearing 5 and guide bearing 19 from top to bottom respectively in it.The gravity of swing part thrust magnetic bearing 5 thus supports.Hollow balance staff 6 is loaded in the described two bearings, and with guide bearing 19 for being slidingly matched.Electromagnet lead-in wire 7 is through in the balance staff 6, the upper end links to each other with excitation driving circuit 2 with brush 22 by collector ring 23, the lower end links to each other with the coil 9 of electromagnet 8 inside that balance staff 6 lower ends install, another of coil line ground connection, thus realize excitation driving circuit 2 control electromagnet 8.Electromagnet 8 centers have up big and down small through hole, and pendulum rope 10 passes described through hole and is stuck in the through hole, and electromagnet 8 lower ends have circular groove, and armature 11 is connected by the hollow cylinder 13 of the disk 12 on top and bottom and forms, and disk 12 is loaded in the above-mentioned groove.Pendulum rope 10 pendulums 4 that pass armature 11 and lower end link to each other, and are installed with block 14 and spring 15 on the pendulum rope 10 between pendulum 4 and the armature 11 successively, 11 times end in contact of spring 15 and armature.Armature 11 keeps contacting with electromagnet 8 parts under the effect of spring 14.Install laser designator 21 under the pendulum 4.Over against pendulum 4 belows index plate 16 is housed, photoelectric sensor 17 is installed in center on it, and photoelectric sensor 17 is linked to each other with excitation driving circuit 2 by lead 18.

The initial excitation of pendulum 4 is by manually finishing.When the equilibrium position was left in pendulum 4 motions, armature 11 kept slight contact force Yi Bian the disk 12 of upper end has all the time with electromagnet 8 under the effect of spring 14, form a fulcrum, can form the gap between another side and the electromagnet 8.Photoelectric sensor 17 reaches excitation driving circuit 2 by laser designator 21 with signal, realize and swing synchronously, excitation electromagnet 8 when pivot angle reaches maximum, at this moment, disk 12 can rotate around above-mentioned fulcrum under magneticaction, realizes excitation.To the plumb position, stop excitation at pendulum.This magnetic force strictness attracts pendulum 4 to swing to the equilibrium position along swaying direction.Motivational techniques in like manner in the time of oppositely.After after a while, just can on index plate 16, see the motion excursion of pendulum, can verify the rotation of the earth.

Claims

1. the drive unit of a pendulum, comprise power supply (1), excitation driving circuit (2), frame (3) and pendulum (4), it is characterized in that: frame (3) goes up installation shaft bearing (20), thrust magnetic bearing (5) and guide bearing (19) from top to bottom are housed respectively in it, hollow balance staff (6) is loaded in the described two bearings, electromagnet lead-in wire (7) is through in the balance staff (6), the upper end links to each other with excitation driving circuit (2) with brush (22) by collector ring (23), the lower end links to each other with the inner coil (9) of electromagnet (8) that balance staff (6) lower end installs, electromagnet (8) center has up big and down small through hole, pendulum rope (10) passes described through hole and is stuck in the through hole, electromagnet (8) lower end has circular groove, armature (11) is connected by the hollow cylinder (13) of the disk (12) on top and bottom and forms, disk (12) is loaded in the groove, the pendulum (4) that pendulum rope (10) passes armature (11) and lower end links to each other, be installed with block (14) and spring (15) on the pendulum rope (10) between pendulum (4) and the armature (11) successively, spring (15) and armature (11) is end in contact down, install laser designator (21) under the pendulum (4), over against pendulum (4) below index plate (16) is housed, photoelectric sensor (17) is installed in center on it, and photoelectric sensor (17) is linked to each other with excitation driving circuit (2) by lead (18).