977 results about "Longitudinal vibration" patented technology

An orthopedic surgical device with compound ultrasound vibration that comprises a handpiece, a surgical cutter fixed on the anterior top of the handpiece, and an ultrasound signal generator. Inside the outer casing of said handpiece, there are provided: an ultrasound transducer for transforming the ultrasound signals from said ultrasound signal generator into ultrasound mechanical waves; a horn (or amplitude transformer) for amplifying vibration amplitude of ultrasound mechanical waves generated from said transducer and then transmitting the amplified ultrasound mechanical waves to said surgical cutter to lead to longitudinal vibration of the surgical cutter; a driving motor fixed in the back end of said handpiece for driving said ultrasound transducer and horn to accomplish the movement of swing and rotation; an adapter provided between said driving motor and said transducer for supplying ultrasonic electrical signals generated by said ultrasound signal generator to said ultrasound transducer.

An ultrasonic calculus treatment apparatus includes a longitudinal-vibration piezoelectric oscillator for vibrating in the axial direction of an ultrasonic transmitting member and a torsional-vibration piezoelectric oscillator for vibrating about the axial direction, and further includes driving circuits for driving the piezoelectric oscillators at respective resonance frequencies and a mode selection switch for permitting the oscillators to vibrate independently or in combination, so that lithotripsy can be performed effectively in accordance with the size of a calculus or a function of an operating tool.

Problems to be SolvedSurgical operation or others excellent in operability, safety, operation efficiency and precision are realized by outputting a vertical-torsional composite vibration through conversion processing of the longitudinal vibration from an ultrasonic oscillation mechanism and reducing the displacement speed of the non-working plane in a female portion less than the speed of the working plane.Means to Solve the ProblemA configuration, comprising an ultrasonic oscillation mechanism composed of a longitudinal vibration element, a backing plate and a front plate for generating an ultrasonic vibration, a horn coupled with the ultrasonic oscillation mechanism for amplifying the vibration transmitted from said ultrasonic oscillation mechanism, a vibration conversion mechanism for converting the vibration transmitted from said ultrasonic oscillation mechanism into a composite vibration composed of a longitudinal vibration in the horn central axial direction and a torsional vibration having the horn central axis as fulcrum, and a female portion provided with a working plane and disposed at said horn tip, wherein said ultrasonic oscillation mechanism is composed of one or more groove portions formed on the circumferential surface of the horn or said backing plate, and a speed variation mechanism of torsional vibration in said composite vibration is formed in the female portion, in order to reduce the reciprocating rotation speed of the non-working plane less than the speed of the working plane.

The invention discloses a longitudinal torsion composite supersonic vibration machining device. The longitudinal torsion composite supersonic vibration machining device comprises a longitudinal supersonic vibration energy converter and an ultrasonic amplitude transformer arranged at the front end of the longitudinal supersonic vibration energy converter and integrally connected with the longitudinal supersonic vibration energy converter. The longitudinal supersonic vibration energy converter comprises a back cover plate, a piezoelectric ceramic piece, an electrode plate, a front cover plate, an insulating sleeve and a pre-tightening bolt for connecting the back cover plate, the piezoelectric ceramic piece, the electrode plate, the front cover plate and the insulating sleeve. The ultrasonic amplitude transformer comprises an amplitude transformer index section and an amplitude transformer cylindrical section, the amplitude transformer index section and the front cover plate are designed into a whole, the amplitude transformer cylindrical section is used for being connected with a machining tool, the surface of the amplitude transformer index section is provided with four same spiral grooves, part of longitudinal vibration generated by the longitudinal supersonic vibration energy converter can be converted into torsion vibration through the spiral grooves, and therefore the longitudinal torsion composite supersonic vibration can be generated one the end face of the amplitude transformer cylindrical section. The longitudinal torsion composite supersonic vibration machining device has the advantages of being simple in structure, large in torsion component, high in converting efficiency and the like.

The linear ultrasound electrical motor (LUEM) includes drive oscillator, mover, chassis, and relevant locking gear for fastening them. The drive oscillator includes piezoelectric element and metal elastic body (MEB). The piezoelectric element includes piezoelectric ceramic piece (PCP) of bending vibration, and PCP of longitudinal vibration in use for generating rectilinear vibration. At least one dogtooth contacted to mover is setup on MEB. Slider of guiding bulge is setup on side of mover. The guiding bulge is corresponding to straight-line guidance groove setup on the chassis. The disclosed LUEM is longitudinal and bending composite driving LUEM with prism type oscillator. The drive oscillator is prism type longitudinal bending composite oscillator composed of connection terminals, longitudinal vibration rectangular PCP and front cover board fastened by double end bolts and nuts. The oscillator is as stator of LUEM to generate longitudinal and bending vibration.

The invention relates to an elliptical ultrasonic vibration auxiliary cutting device with an adjustable track, which consists of a transducer, an amplitude transformer and a cutter, wherein the transducer adopts a basic structure of a longitudinal vibration sandwiched piezoelectric chip, has revolution asymmetric characteristic structures of an overlapping structure of semicircular ring-shaped piezoelectric ceramic chips and electrode chips separately, an off-axis type catenary variable-amplitude structure and the like, and initiates and strengthens flexural vibration when longitudinal vibration is output; the amplitude transformer is a cylindrical bar with uniform cross sections, and a relative angle between the amplitude transformer and a front cover plate is adjustable; and the cutter is installed in an offset way in the radial direction at the tail end of the amplitude transformer, and the offset degree can be adjusted. The working frequency of the invention is higher than 20kHz and can better achieve the ultrasonic machining effect; the elliptical cutting track is long, the minor axis proportion is reasonable, so that the advantages of elliptical cutting can be fully used; the elliptical track can be adjusted to better adapt to machining of different machining materials and different cutting consumption; and single-point diamond ultraprecise cutting can be hopefully expanded to machining of iron-based materials and optical crisp and hard materials.

A vibrator apparatus for inducing longitudinal vibrations in a well tubing or casing member for various operations, or for removing stuck tubing or casing. The apparatus includes a vibrator section with spaced apart rotatable shafts carrying eccentric weights and interconnected by timing gears. The shafts are driven by respective pressure fluid motors. The vibrator section is mounted on an isolator section including spaced apart pressure fluid cylinder assemblies for isolating vibrations generated by the apparatus from wellhead structure supporting the apparatus. A fluid flow circuit includes a pump, a manifold, flow control devices for generating fluid flow through the cylinder assemblies and accumulators for damping fluid pressure and flow fluctuations in the circuit.

The invention discloses a friction liner-hoisting steel wire rope dynamic friction drive test device and a friction liner-hoisting steel wire rope dynamic friction drive test method. The device comprises a base frame, a driving mechanism, a friction drive mechanism, a surrounding angle adjusting mechanism, a shock excitation mechanism, a steel wire rope and a condition monitoring mechanism, wherein the base frame comprises a stand column, a lower support platform and an upper support platform; the driving mechanism comprises a motor and a torque sensor; the friction drive mechanism comprises a friction wheel and a brake device; the surrounding angle adjusting mechanism comprises a C bracket and an adjusting wheel; the shock excitation mechanism comprises a transverse shock excitation mechanism and a longitudinal shock excitation mechanism; the condition monitoring mechanism comprises a steel wire rope tension monitoring device, a dynamic contact monitoring device, a steel wire rope vibration monitoring device and a micro-slippage monitoring device. After the device and the method are adopted, the dynamic friction drive characteristic between a friction liner and a hoisting steel wire rope can be simulated in a friction hoisting system when the hoisting steel wire rope is in a dynamic coupling vibration state, so that various changes in the friction drive process under the actions of transverse vibration, longitudinal vibration and transverse and longitudinal coupled vibration can be researched.

A film bulk acoustic-wave resonator encompasses (a) a substrate having a cavity, (b) a bottom electrode partially fixed to the substrate, part of the bottom electrode is mechanically suspended above the cavity, (c) a piezoelectric layer disposed on the bottom electrode, a planar shape of the piezoelectric layer is defined by a contour, which covers an entire surface of the bottom electrode in a plan view, (d) a top electrode on the piezoelectric layer, (e) an intermediate electrode located between the substrate and the piezoelectric layer, and at the contour of the piezoelectric layer, the intermediate electrode is connected to the bottom electrode in the inside of the contour, and (f) a bottom electrode wiring connected to the intermediate electrode extending from the contour to an outside of the contour in the plan view, wherein a longitudinal vibration mode along a thickness direction of the piezoelectric layer is utilized.

An ultrasonic flowmeter includes a flow passage and an ultrasonic transducer for measuring the flow rate in the flow passage wherein the ultrasonic transducer is equipped with a piezoelectric material having electrodes on the opposed surfaces thereof, one of which is used as an ultrasonic wave transmitting / receiving surface and faces the flow passage. The lengths of the sides of the transmitting / receiving surface is so determined that the vibration in the electrode direction is the main mode, preferably that the ratio of the lengths of the sides of the transmission / reception surface to the thickness is not greater than 0.8. Consequently, because the flow meter uses the thickness longitudinal vibration of the piezoelectric material as the main mode, the ultrasonic transducer has a high sensitivity, a high speed response and a small size and the ultrasonic flow meter has a high accuracy and is compact.

The invention discloses a general frequency matching longitudinal-torsional compound ultrasonic vibration milling and drilling device. The device comprises a machine tool main shaft, a main shaft shell, an ultrasonic power supply, an ultrasonic wireless electric energy transmission system, a mounting cylinder, a sleeve, a longitudinal ultrasonic vibration transducer, a hollow spiral groove amplitude change rod, an elastic chuck, a pressing nut and a cutter. The device adjusts the positions of a rubber plug and a sealing ring to change the volume of a fluid in a cylindrical groove or to replace the type of the fluid so as to change the mass of a longitudinal-torsional compound ultrasonic vibrator to compensate the frequency loss or increment in clamping of different cutter rods; and when the different cutter rods are clamped, the consistency of the resonant frequency, the vibration mode and the vibration shape of an ultrasonic device is realized, and the generality of the device is greatly improved. The longitudinal vibration and torsional vibration effects are both enhanced to a certain extent; the working efficiency is greatly improved; and the advantages of longitudinal-torsional compound vibration are preferably exerted.

An electromagnetic active control device for longitudinal vibration of a marine shafting, belonging to the technical field of oceanographic engineering, comprises: an acceleration transducer, a tachometer, a signal analysis and control module, a power amplifier and an electromagnetic actuator, wherein the acceleration transducer and the tachometer are respectively located on a thrust bearing base and a middle shaft and output a measured vibration acceleration electric signal of the base and a photoelectric signal of the shafting to the signal analysis and control module; the signal analysis and control module receives the vibration acceleration electric signal and the photoelectric signal, performs spectrum analysis and characteristic signal extraction on the received signals to generate corresponding action control signals, and outputs the action control signals to the power amplifier for amplification; and the electromagnetic actuator is arranged on the middle shaft and receives the amplified control signals to generate a corresponding longitudinal actuation force applied on the middle shaft, thereby implementing the control for the longitudinal vibration of the shafting. The electromagnetic active control device for longitudinal vibration of the marine shafting effectively reduces the longitudinal vibration of the shafting, so that vibration response of a marine structure is reduced finally, and the control device not only is effective to low frequency line spectra, but also has excellent control effect on broadband random excitation.

The invention discloses a test bed for simulating longitudinal vibration of a marine propulsion shafting. The test bed comprises a movable loading module (1), a base (12), a fixed loading module (3), a transmission shaft (4), a split coupling (6), a thrust bearing (7), an elastic coupling (8), a gearbox (10) and a frequency conversion motor (11). The fixed loading module (3), the transmission shaft (4), the split coupling (6), the thrust bearing (7), the elastic coupling (8), the gearbox (10) and the frequency conversion motor (11) are arranged on the base (12) in turn. The movable loading module (1) is connected with the fixed loading module (3) through an ejector rod (2) and used for supplying longitudinal alternating exciting force for simulating a propeller. The fixed loading module (3) is connected with one end of the transmission shaft (4). The other end of the transmission shaft (4) is connected with a thrust shaft of the thrust bearing (7) through the split coupling (6). The other end of the thrust shaft is connected with the output shaft of the gearbox (10) through the elastic coupling (8). The gearbox (10) is connected to the frequency conversion motor (11). The test beddisclosed by the invention has the advantages of compact structure, convenient operation, safety and reliability and can satisfy practical application requirements for teaching and researching.

The disclosed variation pole is quadrangular body with rectangular section thinned gradually from two ends to central section. Drive feet are located at middle position of the pole. Piezoelectric ceramic piece in longitudinal vibration and piezoelectric ceramic piece in bending vibration are respectively installed on inner and outer sides of bolts on two flange bolts. Two end plates are installed on outer sides of bolts on two flange bolts. Through two flange bolts, two end plates, two groups of piezoelectric ceramic piece, and thin copper sheet are fastened and integrated to two larger ends of the pole. Advantages are: simple structure, smooth operation, large output thrust, and motion in high speed.

The invention discloses a separated super-magnetostrictive telescopic rotary ultrasonic vibration head which comprises a cutter handle, a variable amplitude rod, a cutter, a permanent magnet body, a super-magnetostrictive telescopic rod, a first magnetic conduction piece and a second magnetic conduction piece, a coil and a coil support; the super-magnetostrictive telescopic rod is sleeved on the permanent magnetic body and coaxial with the permanent magnetic body; a filling gap is formed between the super-magnetostrictive telescopic rod and the permanent magnetic body; the coil is sleeved on the super-magnetostrictive telescopic rod; ultrasonic alternating current is fed into the coil to generate an alternating magnetic field so as to drive the super-magnetostrictive telescopic rod to generate ultrasonic longitudinal vibration; and the coil support is arranged on the periphery of the coil for installing the coil. According to the ultrasonic vibration head provided by the embodiment of the invention, the coil and the cutter handle are separated, so that the energy transmission efficiency is improved while the non-contact transmission of ultrasonic energy is realized, and the output power and the output amplitude are increased under the same conditions.

The invention relates to a hollow shafting particle damper, which is used for comprehensively controlling shafting vibrations. The hollow shafting particle damper comprises two identical semi-cylindrical damping units and a positioning device, wherein the positioning device is positioned between the two semi-cylindrical damping units and is used for fixing the two semi-cylindrical damping units in a hollow shaft. The damper can effectively control the torsional vibration, transverse vibration and longitudinal vibration of a shafting, and is a comprehensive control device for the vibration of the shafting in three directions. The damper is arranged in the shafting so as to effectively make use of the inner space of the shafting and save cost and space.

The invention discloses a longitudinal-torsional resonance ultrasonic vibration device, and relates to the field of ultrasonic processing and precise cutting. The problems that when an existing torsional vibration device applied to milling machining carries out torsional vibration, internal friction of a material loses most energy, and consequently, the torsional amplitude is small, and the energy utilization efficiency is low are solved. The device comprises a ladder type hollow cylinder cone composite body, a longitudinal-torsional conversion hollow cylinder, a pre-tightening bolt, the even number of piezoelectric ceramic pieces and a plurality of electrode pieces; the ladder type hollow cylinder cone composite body is mainly composed of an axial locating shaft, a cylindrical longitudinal-torsional conversion body, a conical torsional vibration amplifying body and a cylindrical longitudinal vibration amplifying body which are coaxially and sequentially arranged and are manufactured into a whole; and the ladder type hollow cone composite body, the longitudinal-torsional conversion hollow cylinder body, the even number of piezoelectric ceramic pieces and the electrode pieces are connected together through the pretightening bolt. The longitudinal-torsional resonance ultrasonic vibration device is used for ultrasonic vibration machining.

The invention relates to an experimental device for researching a drill column dynamic characteristic. The experimental device comprises a main machine frame, a well-wall-simulating assembly, a rotary assembly, a disc assembly, an excitation assembly, a weighing assembly and a detecting device. The well-wall-simulating assembly comprises an organic glass tube, a fixing clamping and a clamp mounting plate. The rotary assembly is provided with a motor, a driver, a coupler, a thin steel column and a top mounting plate, the rotary assembly penetrates through the whole main machine frame, the disc assembly comprises a disc and a cylinder, the disc is arranged on a floating platform, and the disc conducts rotary movement in the cylinder. An exciter in the excitation assembly excites the bottom of the disc according to the input signal type to simulate interaction of a drill head and rocks at the bottom of a borehole. The detecting device comprises a whirling motion track and a transverse vibration and longitudinal vibration detecting device. The experimental device for researching the drill column dynamic characteristic can simulate the vibration and deformation situations of a drill column and determine the parameters of the rotating speed, the bit pressure similarity ratio and the like according to the dynamic similarity ratio and the geometric similarity ratio.

The invention discloses an underground drill stem vibration damping and pressurizing device, which is a complete tool for use in oil and natural gas drilling operation and comprises an upper adapter, a spring, a central shaft, a piston shaft, a locking nut, a water inlet valve, a sealing assembly, a pressurizing cylinder, a pressurizing cylinder centralizing barrel, a pressurizing cylinder outer barrel, a water outlet valve, a high-pressure runner and a lower adapter. During drilling, when generating longitudinal vibration, a drill stem drives the adapters, a spring upper plug connector, the central shaft and the piston shaft to move up and down together relative to the pressurizing cylinder; and drilling fluid is sucked and compressed in the pressurizing cylinder. While transmitting power and circulating the drilling fluid, the device absorbs the energy generated in the vibration of the drill stem and converts the vibrational energy of the drill stem into the pressure of the drillingfluid to pressurize the drilling liquid at the bottom of the well. The device damps the vibration of the drill stem, protects the drill stem, increases the jet pressure of a drill bit nozzle and improves rock breaking efficiency.

A linear ultrasonic motor of sandwich transducer type with FM variable - amplitude rod is prepared as firm-connecting longitudinal-flexural vibration piezoelectric ceramic wafer and thin copper plate with big end of end cover through double-screw bolt and small end of end cover to big end of FM variable - amplitude rod through driving foot, arranging said driving foot and flexural vibration piezoelectric wafer separately at vibration wave loop of flexural vibration for setting polarization directions of flexural and longitudinal vibration piezoelectric ceramic wafer and setting length of variable-amplitude rod to be 1 / 2 of longitudinal vibration wavelength.

The invention relates to an ultrasonic vibration unit (10) for an ultrasonic welding device for sealing and welding material webs, comprising a sonotrode (12) connected to a converter (14) and having at least one sealing horn (16) radially protruding from an axis of rotation (a) and rotatable about the axis of rotation (a) and having a free end forming a sealing surface (18). The sonotrode (12) comprises a sonotrode shaft (20) having the axis of rotation (a). One or both end faces (22) of the sonotrode shaft (20) are connected to a converter (14) and the sealing horns (16) are attached to the sonotrode shaft (20) directly or by means of boosters (24, 26) when vibrational nodes (KL) of a longitudinal vibration (SWI) of the sonotrode shaft (20) are present.

The invention pertains to a mechanically processing tool, relating to an ultrasonic burr removal tool and method for complex casing deep small holes. The invented device and method transform alternating current of 50Hz to supersonic mechanical vibration, the vibration amplitude of mechanical vibration is enlarged by an amplitude transformer bar and is transmitted to a vibration transmission bar to drive the superhard abrasive material thereon to vibrate longitudinally, impact the machined surface with a big velocity and generate maximal compressive force on a unit area to make the material to deform, crack and be peeled off as uncountable microparticles, so that to achieve the burr removal objective. The burr removal ultrasonic can reach position where manual tools are difficult to reach; man-made and environmental affecting factors are small, burrs are removed evenly and thoroughly, the processing accuracy and processing quality are easy to be ensured and controlled, the burrs are removed with identical degrees, and positions where burrs are removed have a same shape; the invented tool and method are suitable for processing holes with middle and small diameters and large length-diameter ratio in complex casing parts, especially holes smaller that phi 3; the processing time is short, and the processing efficiency is enhanced by over 50%.

The invention relates to an ultrasonic bending fatigue experimental device, wherein a transducer is positioned in a force transmitter and connected with a connector. The transducer is positioned in the middle of the ultrasonic bending fatigue experimental device; a backing plate and an upper connecting plate as well as a lower connecting plate of the force transmitter are fixedly connected through force transmitting rods. One end of the connector penetrates through the lower connecting plate at the lower end of the force transmitter and is connected with a displacement amplifier, and the other end penetrates through the upper connecting plate and is connected with the transducer. A supporting device is positioned below the displacement amplifier; and a static load force applying device penetrates through the central hole of the backing plate and is fixedly connected with the backing plate. The transducer, the connector, the displacement amplifier and a pressure head form a longitudinal resonance system, and a longitudinal vibration load is transferred to a bending fatigue sample through the pressure head, so that bending vibration is generated by the bending fatigue sample. The position of the supporting point of the bending fatigue sample can be automatically regulated through a positioning guide screw to realize an ultrasonic bending fatigue experiment, the ultrasonic bending fatigue experiments of the samples with different loading loads and different geometrical sizes can be realized, and the ultrasonic bending fatigue experimental device is suitable for carrying out the bending fatigue experiment by utilizing an axial loading ultrasonic fatigue experiment machine.

A piezoelectric resonator component includes an energy-trapped piezoelectric resonator utilizing a third order harmonic wave of thickness longitudinal vibration and including a piezoelectric substrate having first and second major surfaces and polarized in a direction of thickness between the first and second major surfaces, and first and second vibrating electrodes opposed to each other with the piezoelectric substrate interposed therebetween, and first and second casing substrates respectively laminated on the first and second major surfaces of the piezoelectric resonator so that cavities are arranged so as not to interfere with vibration of a vibration section where the first and second vibrating electrodes face each other through the piezoelectric substrate. The first and second vibrating electrodes are dimensioned so that the difference between the peak values of the phases of S0 and S1 modes of the fundamental wave of the thickness longitudinal vibration falls within a range of about ±5 degrees.

The invention discloses a single-electrical signal-stimulated rotation ultrasonic motor which comprises a mandrel, a group of piezoelectric ceramic sheets, a window-shaped staggered mode converter, a friction disk, a bearing, a spring and a nut, wherein the piezoelectric ceramic sheets, the window-shaped staggered mode converter, the friction disk, the bearing, the spring and the nut are sequentially sleeved on the mandrel, the piezoelectric ceramic sheets are connected with electrode sheets, the mandrel, the piezoelectric ceramic sheets, the electrode sheets and the window-shaped staggered mode converter form the stator part of the ultrasonic motor, the friction disk and the bearing form the rotor part of the ultrasonic motor, and the spring and the nut form a positive-pressure pretightening force adjusting mechanism of the rotor and the stator parts of the ultrasonic motor. In the invention, a single-electrical signal-stimulated working mode is adopted, the elliptical orbit motion of stator end surface particles is realized by utilizing the longitudinal vibration mode of the group of piezoelectric ceramic sheets, a rotor is driven to rotate, and the ultrasonic motor has simple control-driven system, easy manufacture, easy miniaturization and integration, low cost, small control difficulty and broad application prospect.

The present invention relates to a mixed control system of main beam longitudinal vibration reaction of floated type cable-stayed bridge. It is characterized by that in the bridge tower and bridge main beam connected place of said highway and railway dual-purpose or railway special-purpose floated cable-stayed bridge the MR damper and fluid damper are longitudinally set and combined together. Said invention also provides the control method of said mixed control system, and said control method includes the following steps: utilizing fluid damper to provide fluid damping force of unadjustable parameter, utilizing MR damper to provide coulomb damping force of adjustable parameter, then utilizing longitudinal relative displacement reaction of main beam and bridge tower and longitudinal speed reaction of bridge tower to actively regulate amplitude of coulomb damping force so as to inhibit the main beam longitudinal vibration reation of said cable-stayed bridge which is resulted from train brake and train running.

The invention discloses an ultrasonic laser composite dressing device for a superabrasive grinding wheel. The ultrasonic laser composite dressing device is mainly formed by an ultrasonic vibration dressing system, a laser transmitting system and a lathe bed. A laser transmitter transmits energy to a laser focusing head with a focusing head fixing and adjusting device through optical fibers, laser beams are focused during work to heat the rotating grinding wheel in front of a dressing point at proper energy density for proper heating time, an ultrasonic generator transmits an ultrasonic frequency signal to an ultrasonic transducer, the ultrasonic frequency signal is converted into mechanical vibration through the transducer to be transmitted to an amplitude-change pole, waves, generating longitudinal vibration, of the amplitude-change pole will be decomposed at the position, where a diamond slot is formed, of the small end, the vibration type involves longitudinal vibration and bending vibration, composite elliptical ultrasonic vibration is formed at the point of a diamond dressing stylus for dressing, and after the dressing stylus completely disengages from the grinding wheel, the dressing stylus will be moved to the position where dressing is started for the next time and starts dressing for the next round. In the dressing process, under the recombination action of ultrasonic vibration and laser auxiliary heating, removal of partial materials of the grinding wheel is changed from brittle removal into plastic removal, cutting force is reduced, abrasion to the dressing stylus is reduced, and the dressing efficiency and dressing result are improved.