Sandwich type cylinder stator and use the ultrasound electric machine of this stator
Technical field
The present invention relates to a kind of sandwich type cylinder stator and use the ultrasound electric machine of this stator, belong to the piezoelectric ultrasonic motor technical field.
Background technology
Piezoelectric ultrasonic motor is a kind of inverse piezoelectric effect of utilizing piezoelectric ceramic, in elastomer, motivate the vibration in the supersonic range, form particle movement at surface of elastomer specified point or specific region with particular track, and then the microscopic motion of particle is converted to the macroscopic motion of rotor by the friction between stator, rotor coupling, have low speed high torque, need not gear, no electromagnetic interference, advantage such as response speed is fast and cut off self-lock, have very as a kind of piezoelectric actuator and to use widely.For the simplicity of exiting principle and the simplicity of theoretical analysis method, piezoelectric ultrasonic motor adopts the mode of metallic elastic body stickup piezoelectric ceramic thin sheet to encourage mostly at present, owing to be subjected to the d of piezoelectric ceramic
31Pattern mechanical-electric coupling efficient and ceramic material tensile strength are low, and the restriction of the intensity of glue-line and fatigue life etc., and such energisation mode makes the mechanical fan-out capability of ultrasound electric machine be subjected to serious restriction.
Summary of the invention
, to the invention provides a kind of sandwich type cylinder stator and use the ultrasound electric machine of this stator because the problem that the mechanical fan-out capability that adopts the mode of metallic elastic body stickup piezoelectric ceramic thin sheet to encourage to cause is restricted in order solving that existing ultrasound electric machine exists.
The sandwich type round plate stator, it is formed by driving cylinder and even number driven unit; Described driving cylinder is made up of cylinder, thin-walled ring and flange; Described thin-walled ring is arranged between cylinder and the flange; The central shaft of the central shaft of described cylinder, thin-walled ring and the central shaft of flange are positioned on the same axis; Described driven unit is made up of two cantilever beams, four piezoelectric ceramic pieces, adjustment pad, copper plate electrode, pretension screw, pre-load nut and insulating cases; Fixedly connected with the outer surface of cylinder in the side end face of described two cantilever beams, four piezoelectric ceramic pieces are installed between described two cantilever beams, be equiped with the adjustment pad between two pairs of piezoelectric ceramic pieces, between every adjacent two piezoelectric ceramic pieces, between piezoelectric ceramic piece and the adjustment pad and be equiped with copper plate electrode respectively between cantilever beam and the piezoelectric ceramic piece; Between described piezoelectric ceramic piece, adjustment pad, copper plate electrode and pretension screw, be equiped with insulating case; Described four piezoelectric ceramic pieces are opposite along the polarised direction of thickness direction polarization and adjacent two piezoelectric ceramic pieces; Described cantilever beam, piezoelectric ceramic piece, adjustment pad and copper plate electrode are fastenedly connected by pretension screw and pre-load nut and are integral.
Use the ultrasound electric machine of sandwich type cylinder stator, it is made up of sandwich type cylinder stator, rotor assembly, outer cover, bearing pedestal, bearing pre-tightened lid, bearing, first set screws, second set screws and the 3rd set screws; Described rotor assembly is made up of tape spool rotor, a nothing axle rotor, linking bond, rubber blanket, disk spring, locking nut, packing and expansion loop; A described tape spool rotor and a nothing axle rotor are truncated cone-shaped, and the thin end of tape spool rotor links to each other with the top embedding and by linking bond from the below of sandwich type cylinder stator cylinder respectively with the thin end that does not have a rotor; Packing is installed in the tape spool rotor and does not have the outer surface of axle rotor; Expansion loop is installed in the outer surface of packing; Described bearing pedestal is fixed on the sandwich type cylinder stator flange by first set screws; Described tape spool rotor connects with the rotation of sandwich type cylinder stator by the bearing that is installed on the bearing pedestal, and bearing is realized pretension by the bearing pre-tightened lid and second set screws; Rotor assembly is realized pretension by being installed in the rubber blanket, disk spring and the locking nut that do not have axle rotor upper surface; Outer cover is installed on the sandwich type cylinder stator flange by the 3rd set screws.
Sandwich type cylinder stator provided by the invention, piezo ceramic element adopts sandwich structure, adopts the d of the high mechanical-electric coupling efficient of piezoelectric ceramic
33Pattern work, solve the problem of pasting low, the mechanical fan-out capability difference of piezoelectric ceramic chip piezoelectric ultrasonic motor mechanical-electric coupling efficient, and simplify the structure by the integrated configuration of cylinder and cantilever beam, improved the controllability of cylinder surface of elastomer particle vibration track.When cylinder was operated in n rank flexural vibration mode, the number of the contained driven unit of sandwich type cylinder stator mostly was 2 (n-1) most, wherein n ∈ 2,3,4 ... }, the angle theta between any two driven unit median planes
1Satisfy: θ
1=90 ° * m/n, wherein m ∈ 3 ..., 4n-3}, all driven units are divided into two groups and encourage, the angle theta between any on the same group two driven unit median planes
2Satisfy: θ
2=180 ° * m/n, wherein m ∈ 2 ..., 2n-2}; The number of exponent number and driven unit that output torque that can be according to actual needs and size restrictions are selected the cylinder stator bending vibration modes flexibly.Utilize the extensional vibration of piezoelectric ceramic piece, by the control input signal, realize that two groups of driven units are motivating the bending vibration modes response that two amplitudes are equal, all differ pi/2 on time and space on the stator cylinder, two bending vibration modes responses are superimposed upon and form the row ripple on the stator cylinder, and then stator driving gear surface particle produces elliptical trajectory, by and rotor assembly between the friction coupling realize the macroscopic motion output of rotor.The present invention realizes driven unit longitudinal vibration natural frequency and the curved degeneracy that shakes between the natural frequency of cylinder by the height of adjusting both sides, piezoelectric ceramic piece square-section ratio, barrel bore size, outside diameter of cylinder size and cylinder.The thin-walled ring can realize that resiliency supported and vibration isolate, and drops to the influence degree that connects the flexural vibration mode of cylinder of stator module and exterior part minimum.
The ultrasound electric machine of use sandwich type cylinder stator provided by the invention applies pretightning force by stacking spring and locking nut, because the effect of the conical surface between tape spool rotor, nothing axle rotor and the packing, pretightning force passes to expansion loop by the packing outward radial, and then cause the radial expansion of expansion loop, realized the pretension of rotor assembly and stator module, make simultaneously and interference fit between tape spool rotor, nothing axle rotor and the packing finally realized the rotation output of rotor assembly; Packing axially has groove, has guaranteed that pretightning force is converted into along circumferential uniform radial load, thereby effectively has been delivered on the expansion loop; Expansion loop is very thin becket, produces radial expansion under the effect of the circumferential uniform radial load in the edge that packing produces, thereby makes rotor assembly compress stator, has guaranteed good the contacting of expansion loop with stator driving gear surface; Adopt cylinder to drive between stator module and the rotor assembly, increased the contact area of stator module and rotor assembly, can effectively improve the output torque of motor; Realized the support of rotor assembly by being installed in bearing on the bearing pedestal, can reduce the influence of radial load the motor output characteristic.
But that stator provided by the invention and ultrasound electric machine have is simple in structure, flexible design, mechanical-electric coupling efficient height, can realize big moment output, stable performance, be easy to control the advantage of producing in serial form.
Description of drawings
Structural representation when the sandwich type cylinder stator that Fig. 1 proposes for the present invention comprises 4 driven unit 1-8; Fig. 2 is the sectional elevation of Fig. 1; Fig. 3 is the structural representation that drives cylinder 1-1 in the sandwich type cylinder stator; Fig. 4 is the polarised direction schematic diagram of the piezoelectric ceramic piece 1-8-2 of 4 driven unit 1-8 in the sandwich type cylinder stator; Fig. 5 is the longitudinal section of the ultrasound electric machine of sandwich type cylinder stator; Fig. 6 is to use the structural representation of packing 2-7 in the ultrasound electric machine of sandwich type cylinder stator; Fig. 7 is the driven unit 1-8 pumping signal input schematic diagram in the sandwich type cylinder stator shown in Figure 1, and wherein the ac voltage signal of importing among the figure satisfies: V
1=Acos (2 π t/T), V
2=Asin (2 π t/T), V
0=0, V
1Be the voltage excitation signals of first group of sandwich driven unit, V
2It is the voltage excitation signals of second group of sandwich driven unit, A is the driving voltage signal amplitude, T is the driving voltage signal period, and t is the time, and the voltage excitation signals amplitude of two groups of driven units equates, frequency is that driven unit self longitudinal vibration resonance frequency, phase difference are+90 °; Fig. 8 to Figure 11 is that the driven unit 1-8 in the sandwich type cylinder stator adopts when ac voltage signal encourages as shown in Figure 7, an interior vibration shape of complete vibration period changes schematic diagram, be stator circumferentially deploying figure, the vibration shape that is specially stator five rank bending vibration modes changes schematic diagram; Fig. 8 is t=nT (n=0,1,2...) Shi Ke a stator vibration shape schematic diagram; Fig. 9 is t=(n+1/4) T (n=0,1,2...) Shi Ke a stator vibration shape schematic diagram; Figure 10 is t=(n+1/2) T (n=0,1,2...) Shi Ke a stator vibration shape schematic diagram; Figure 11 is t=(n+3/4) T (n=0,1,2...) Shi Ke a stator vibration shape schematic diagram.
Embodiment
Embodiment one: in conjunction with Fig. 1~Fig. 4 present embodiment is described, present embodiment is formed by driving cylinder 1-1 and even number driven unit 1-8; Described driving cylinder 1-1 is made up of cylinder 1-1-1, thin-walled ring 1-1-2 and flange 1-1-3; Described thin-walled ring 1-1-2 is arranged between cylinder 1-1-1 and the flange 1-1-3; The central shaft of the central shaft of described cylinder 1-1-1, thin-walled ring 1-1-2 and the central shaft of flange 1-1-3 are positioned on the same axis; Described driven unit 1-8 is made up of two cantilever beam 1-8-1, four piezoelectric ceramic piece 1-8-2, adjustment pad 1-8-3, copper plate electrode 1-8-4, pretension screw 1-8-5, pre-load nut 1-8-6 and insulating case 1-8-7; Fixedly connected with the outer surface of cylinder 1-1-1 in the side end face of described two cantilever beam 1-8-1, four piezoelectric ceramic piece 1-8-2 are installed between described two cantilever beam 1-8-1, be equiped with between two couples of piezoelectric ceramic piece 1-8-2 and adjust pad 1-8-3, between the piezoelectric ceramic piece 1-8-2, between piezoelectric ceramic piece 1-8-2 and the adjustment pad 1-8-3 and be equiped with copper plate electrode 1-8-4 respectively between cantilever beam 1-8-1 and the piezoelectric ceramic piece 1-8-2; Between described piezoelectric ceramic piece 1-8-2, adjustment pad 1-8-3, copper plate electrode 1-8-4 and pretension screw 1-8-5, be equiped with insulating case 1-8-7; Described four piezoelectric ceramic piece 1-8-2 are opposite along the polarised direction of thickness direction polarization and adjacent two piezoelectric ceramic piece 1-8-2; Described cantilever beam 1-8-1, piezoelectric ceramic piece 1-8-2, adjustment pad 1-8-3 and copper plate electrode 1-8-4 are fastenedly connected by pretension screw 1-8-5 and pre-load nut 1-8-6 and are integral.When cylinder was operated in n rank flexural vibration mode, the number of the contained driven unit of described sandwich type cylinder stator (1-8) mostly was 2 (n-1) most, wherein n ∈ 2,3,4 ... }, the angle theta between any two driven units (1-8) median plane
1Satisfy: θ
1=90 ° * m/n, wherein m ∈ 3 ..., 4n-3}, all driven units (1-8) are divided into two groups and encourage, the angle theta between any on the same group two driven units (1-8) median plane
2Satisfy: θ
2=180 ° * m/n, wherein m ∈ 2 ..., 2n-2}.
The operation principle of the described sandwich type cylinder stator of present embodiment is: described driven unit (1-8) employing encourages with the alternating voltage of self longitudinal vibration resonance frequency same frequency, all driven units (1-8) are divided into two groups and encourage, as Fig. 7~shown in Figure 11, two groups of driven units adopt amplitude to equate, frequency is driven unit self a longitudinal vibration resonance frequency, phase difference is ac voltage signal when excitation of+90 °, utilize the extensional vibration of piezoelectric ceramic piece to be implemented in to motivate two amplitudes on the stator cylinder and equate, on time and space, all differ the bending vibration modes response of pi/2, two bending vibration modes responses are superimposed upon and form the row ripple on the stator cylinder, driving gear surface particle produces elliptical trajectory, and then realizes the macroscopic motion output of rotor by the coupling of the friction between driving gear and the rotor; If adjusting the phase difference of excitation signals is-90 °, can change capable wave line of propagation, finally realize the rotor counter motion; Realize driven unit longitudinal vibration natural frequency and the curved degeneracy that shakes between the natural frequency of cylinder by the height of adjusting both sides, piezoelectric ceramic piece square-section ratio, barrel bore size, outside diameter of cylinder size and cylinder; The thin-walled ring can realize that resiliency supported and vibration isolate, and drops to the influence degree that connects the flexural vibration mode of cylinder of stator module and exterior part minimum; Adjust pad by reconditioning, realize the electroceramics sheet, adjust pad and copper plate electrode thickness and the groove width between a pair of cantilever beam under the definite value pretightning force that pretension screw and pre-load nut apply and equate.
Embodiment two: present embodiment and embodiment one difference are that described cylinder 1-1-1, thin-walled ring 1-1-2, flange 1-1-3 and cantilever beam 1-8-1 adopt a block of metal materials processing to be integral part.Other composition is identical with embodiment one with connected mode.Adopt this structure can reach the purpose that reduces energy loss, help improving the controllability of driving gear surface particle vibration track.
Embodiment three: present embodiment and embodiment one difference are that the distance between two median planes of two cantilever beam 1-8-1 is the wavelength of half cylinder flexural vibrations.Other composition is identical with embodiment one with connected mode.
Embodiment four: in conjunction with Fig. 1~Fig. 4 present embodiment is described, present embodiment and embodiment one difference are that the inner surface of described cylinder 1-1-1 is processed with continuous pectination driving gear 1-1-4.Other composition is identical with embodiment one with connected mode.The purpose that increases continuous pectination driving gear 1-1-4 is to amplify sandwich type cylinder stator cylinder 1-1-1 surface particle vibration trajectory amplitudes, improves the mechanical output characteristic of stator.
Embodiment five: present embodiment and embodiment one difference are that the cross section of the contact area of described cantilever beam 1-8-1, piezoelectric ceramic piece 1-8-2, adjustment pad 1-8-3 and copper plate electrode 1-8-4 and piezoelectric ceramic piece 1-8-2 is a rectangle.Other composition is identical with embodiment one with connected mode.This shape is simplified processing process well.
Embodiment six: in conjunction with Fig. 5, Fig. 6 present embodiment is described, present embodiment is made up of embodiment one described sandwich type cylinder stator, rotor assembly 2, outer cover 3, bearing pedestal 4, bearing pre-tightened lid 5, bearing 6, first set screws 7, second set screws 8 and the 3rd set screws 9; Described rotor assembly 2 is made up of tape spool rotor 2-1, a nothing axle rotor 2-2, linking bond 2-3, rubber blanket 2-4, disk spring 2-5, locking nut 2-6, packing 2-7 and expansion loop 2-8; A described tape spool rotor 2-1 and a nothing axle rotor 2-2 are truncated cone-shaped, and the thin end of tape spool rotor 2-1 links to each other with the top embedding and by linking bond 2-3 from the below of sandwich type cylinder stator cylinder 1-1-1 respectively with the thin end that does not have a rotor 2-2; Packing 2-7 is installed in tape spool rotor 2-1 and does not have the outer surface of axle rotor 2-2; Expansion loop 2-8 is installed in the outer surface of packing 2-7; Described bearing pedestal 4 is fixed on the sandwich type cylinder stator flange 1-1-3 by first set screws 7; Described tape spool rotor 2-1 connects with the rotation of sandwich type cylinder stator by the bearing 6 that is installed on the bearing pedestal 4, and bearing 6 is realized pretensions by bearing pre-tightened lid 5 and second set screws 8; Rotor assembly 2 is realized pretension by being installed in rubber blanket 2-4, the disk spring 2-5 and the locking nut 2-6 that do not have axle rotor 2-2 upper surface; Outer cover 3 is installed on the sandwich type cylinder stator flange 1-1-3 by the 3rd set screws.Adopt cylinder to drive between the sandwich type cylinder stator of the ultrasound electric machine of the use sandwich type cylinder stator in the present embodiment and the rotor assembly 2, increased the contact area of sandwich type cylinder stator and rotor assembly 2, effectively improve the output torque of motor; Realized the support of rotor assembly by being installed in bearing 6 on the bearing pedestal 4, reduced the influence of radial load the motor output characteristic.Outer cover 3 has been realized the encapsulation of motor and protection.
Embodiment seven: present embodiment and embodiment six differences are to have on the packing 2-7 groove of the direction that parallels to the axis; Other composition is identical with embodiment six with connected mode.The purpose that has groove is that pretightning force is converted into along circumferential uniform radial load, guarantees that pretightning force is delivered on the expansion loop 2-8 effectively.
Embodiment eight: in conjunction with Fig. 6 present embodiment is described, present embodiment is that with embodiment six differences packing 2-7 inner surface has and a tape spool rotor 2-1 outer surface and the identical tapering of nothing axle rotor 2-2 outer surface.Other composition is identical with embodiment six with connected mode.This structure can guarantee that the pretightning force that applies by disk spring 2-5 and locking nut 2-6 passes to expansion loop 2-8 by packing 2-7 outward radial, and then cause the radial expansion of expansion loop, realized the pretension of rotor assembly 2 and sandwich type cylinder stator, guaranteed good the contacting of expansion loop 2-8 with sandwich type cylinder stator driving gear 1-1-5 surface, make simultaneously and interference fit between tape spool rotor 2-1, nothing axle rotor 2-2 and the packing 2-7 finally realized the rotation output of rotor assembly 2.