CN104930974A - No-fixed displacement meter capable of directly measuring dynamic displacement of measurement point - Google Patents

Abstract

The invention discloses a no-fixed displacement meter capable of directly measuring the dynamic displacement of a measurement point. The displacement meter comprises a mass, a spring, a damper, a displacement meter casing, a sleeve, a torsion spring, guide rods, a laser probe, a displacement meter base and a measured object. The displacement meter base is fixedly connected with the lower part of the displacement meter casing. Left and right guide rods are oppositely arranged and extend out the displacement meter casing. The mass is connected with the upper end of the displacement meter casing through the spring and the damper. The sleeve is arranged on the joint of the guide rods and the displacement meter casing. The sleeve is hinged with the displacement meter casing and is connected with the torsion spring. The laser probe is aligned to the mass and is fixed on the displacement meter base. According to the invention, the provided displacement meter does not require a fixed reference point, can be directly arranged on the measured object, and is prevented from external disturbances.

Description

A kind of displacement meter moving displacement without the need to fixing directly measurement measuring point

Technical field

The invention belongs to displacement meter field, be specifically related to a kind of displacement meter moving displacement without the need to fixing directly measurement measuring point.

Background technology

Vibration displacement test is the key content that the Engineering Vibration problems such as building, machinery, aviation boat need to solve.The design of sensor is that current displacement meter product is a lot, have laser displacement gauge, electromagnetic eddy displacement meter, Optical Fiber Grating Displacement Meter etc., but the displacement of all engineer applied all must have a fixed reference point when measuring displacement.In Practical Project, these point of fixity are provided to be very difficult.Many researchers is devoted to design a kind of sensor that can be placed on just energy output displacement on testee as accelerometer, and prior art has laser displacement gauge, current vortex displacement meter, Optical Fiber Grating Displacement Meter.But, in current all engineerings during displacement measurement amount testee vibration displacement, all needed one and testee completely independently point of fixity; Output data are subject to displacement meter mounting points and reference point locations disturbing factor is larger; Seismological bureau uses displacement meter bulky, can not apply.

Summary of the invention

An object of the present invention is for solving an above-mentioned difficult problem, provides one not need permanent datum, and what directly can be installed on testee directly measures without the need to fixing the displacement meter that measuring point moves displacement.

The invention provides a kind of displacement meter moving displacement without the need to fixing directly measurement measuring point, comprising: mass, spring, damper, displacement meter shell, sleeve, torsionspring, guide rod, laser probe and displacement meter base; Described displacement meter base is fixed on below described displacement meter shell; Relatively respectively be provided with one about described guide rod, and pass described displacement meter shell; Described mass is connected with described displacement meter shell upper end with damper by spring; Described guide rod and displacement meter shell junction are provided with sleeve, and described sleeve is connected by described torsionspring with displacement meter housing hinge simultaneously; Described laser probe to be just fixed on described displacement meter base described mass.

Beneficial effect of the present invention is, a kind of displacement meter moving displacement without the need to fixing directly measurement measuring point provided by the invention mainly utilizes constant variable system building method to design the plan spring mass system of the low natural frequency of a kind of low additional mass, design the displacement meter directly exporting measuring point displacement based on this, do not need permanent datum; Can directly be installed on testee; Little by external interference factor.

Accompanying drawing explanation

Figure 1 shows that the present invention is a kind of and directly measure without the need to fixing the structural drawing that measuring point moves the displacement meter of displacement.

Embodiment

Hereafter will describe the specific embodiment of the invention in detail in conjunction with concrete accompanying drawing.It should be noted that the combination of technical characteristic or the technical characteristic described in following embodiment should not be considered to isolated, they can mutually be combined thus be reached better technique effect.

As shown in Figure 1, the invention provides a kind of displacement meter moving displacement without the need to fixing directly measurement measuring point, comprising: mass 1, spring 2, damper 3, displacement meter shell 4, sleeve 5, torsionspring 6, guide rod 7, laser probe 8 and displacement meter base 9; Displacement meter base 9 is fixed on below displacement meter shell 4; Guide rod about 7 is relatively respectively provided with one, and passes displacement meter shell 4; Mass 1 is connected with displacement meter shell 4 upper end with damper 3 by spring 2; Guide rod 7 and displacement meter shell 4 junction are provided with sleeve 5, are connected the while that sleeve 5 being hinged with displacement meter shell 4 by torsionspring 6; Laser probe 8 to be just fixed on displacement meter base 9 mass 1.

During use, this displacement meter is placed on testee 10.

Inventive principle:

Mass 1 quality is set to m, and spring 2 spring rate is set to k, and damper 3 damping is set to c, and torsionspring 6 torsional rigidity is set to G, and the distance between sleeve 5 pin joint and mass 1 is set to L.

When displacement meter is static, guide rod 7 keeps horizontal horizontal level, and spring 2 remains on former long status, and the gravity of mass 1 provides balance by torsionspring 6, if now torsionspring 6 torsional deflection angle is α ₀, then

mgL/2＝Gα ₀(1)

When testee 10 vertical motion, suppose that the time dependent function of vibration displacement is Y (t)=A sin ω t, mass 1 is y (t) relative to the vertical displacement of testee 10, then obtain the equation of motion to mass 1 stress analysis

$m(\stackrel{\·\·}{y}+\stackrel{\·\·}{Y})+c\stackrel{\·}{y}+\mathrm{ky}+2G({\mathrm{\α}}_0+\mathrm{\α})/L-\mathrm{mg}=0---\left(2\right)$

Wherein tg α=y/L, obvious α maximum occurrences is no more than pi/2, when design torsionspring 6 makes G very little, α ₀>> pi/2, then combine (1) formula, (2) formula can be reduced to

$m\stackrel{\·\·}{y}+c\stackrel{\·}{y}+\mathrm{ky}=-m\stackrel{\·\·}{Y}=\mathrm{mA}{\mathrm{\ω}}^2\sin \mathrm{\ωt}---\left(3\right)$

Order $k/m={\mathrm{\ω}}_0^2,$ c＝2mξω ₀， $\mathrm{\γ}=\frac{\mathrm{\ω}}{{\mathrm{\ω}}_0}$

Above formula steady state solution

y(t)＝B sin(ωt-θ)

$B=\frac{\mathrm{mA}{\mathrm{\ω}}^2}{k\sqrt{{(1-{\mathrm{\γ}}^2)}^2+{\left(2\mathrm{\ξ\γ}\right)}^2}},\mathrm{\θ}=\mathrm{acr}\tan \frac{2\mathrm{\ξ\γ}}{1-{\mathrm{\γ}}^2}$

When b ≈ A, now has laser probe 8 to record the displacement of mass 1 equal with the displacement of testee 10.Theory shows ξ=0.6 ~ 0.7, and γ >2.5 can be effective.

Therefore, above-mentioned key point needs displacement natural frequency very low, and namely mass 1 quality is very large, or spring 2 rigidity k is very little.If but do not adopt torsionspring 6, guide rod 7, sleeve 5 mechanism elimination gravity according to the present invention, no matter would be adopt tune up quality or reduce rigidity, would all need larger Static Correction space.Key point of the present invention is just a cancellation the impact that deadweight produces Static Correction, makes k rigidity and m Quality Design flexibly, can need design according to range.

A kind of displacement meter moving displacement without the need to fixing directly measurement measuring point provided by the invention mainly utilizes constant variable system building method to design the plan spring mass system of the low natural frequency of a kind of low additional mass, design the displacement meter directly exporting measuring point displacement based on this, do not need permanent datum; Can directly be installed on testee; Little by external interference factor.

Although give some embodiments of the present invention, it will be understood by those of skill in the art that without departing from the spirit of the invention herein, can change embodiment herein.Above-described embodiment is exemplary, should using embodiment herein as the restriction of interest field of the present invention.

Claims (1)

1. directly measure without the need to fixing the displacement meter that measuring point moves displacement, it is characterized in that, comprising: mass, spring, damper, displacement meter shell, sleeve, torsionspring, guide rod, laser probe and displacement meter base; Described displacement meter base is fixed on below described displacement meter shell; Relatively respectively be provided with one about described guide rod, and pass described displacement meter shell; Described mass is connected with described displacement meter shell upper end with damper by spring; Described guide rod and displacement meter shell junction are provided with sleeve, and described sleeve is connected by described torsionspring with displacement meter housing hinge simultaneously; Described laser probe to be just fixed on described displacement meter base described mass.