CN218564255U

CN218564255U - Vibration damper, torsional vibration damping coupler and screw compressor

Info

Publication number: CN218564255U
Application number: CN202222712197.4U
Authority: CN
Inventors: 鲁涵锋; 张龙爱; 周江峰; 王纪遇; 张国栋
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2023-03-03
Anticipated expiration: 2032-10-14

Abstract

The utility model discloses a vibration damper, torsional vibration damping shaft coupling and helical-lobe compressor. The vibration damping device comprises a positive stiffness elastic element and a negative stiffness elastic element which are arranged in parallel, and the installation heights of the positive stiffness elastic element and the negative stiffness elastic element are the same. The screw male rotor and the motor rotor of the screw compressor are coaxially connected through the torsional vibration damping coupler with the vibration damping device, so that static torque transmission and dynamic fluctuation torque isolation can be achieved between the motor rotor and the screw male rotor. Therefore, the mutual influence of excitation coupling and rotating speed pulsation between the motor rotor and the screw rotor can be reduced, the negative influence of motor tooth space torque fluctuation on screw rotor meshing is reduced, the screw meshing working condition is effectively improved, and vibration noise is reduced. The motor rotor and the screw male rotor are supported by the simply supported beams, so that the dynamic eccentricity of the motor rotor is reduced, and the vibration of a motor of the screw compressor is reduced.

Description

Vibration damper, torsional vibration damping coupler and screw compressor

Technical Field

The utility model relates to a reduce the technical field of the vibration that produces because the transmission moment of torsion especially relates to a can reduce the damping device of the torsional vibration who produces and have this damping device's torsional vibration damping coupling and use this torsional vibration damping coupling's helical-lobe compressor by the undulant torsional vibration of rotor speed.

Background

At present, the screw compressor is more and more widely applied in the commercial refrigeration field, but how to control the vibration noise of the compressor is more and more concerned by users. The screw compressor vibration noise characteristic of the traditional structure is analyzed, and the main prominent contribution frequency of the screw compressor in the vibration acceleration and noise sound pressure level frequency spectrum is found to be the meshing frequency of the screw rotors and the harmonic frequencies thereof, namely the generation of the vibration noise of the screw compressor is mainly related to the meshing of the screw rotors. Further review of the literature and research has found that the fluctuation of the rotation speed is one of the important factors affecting the magnitude of the engaging force of the engaging machine. Therefore, people can improve the running stability and reduce the meshing force of the screw by reducing the rotation speed fluctuation of the screw rotor system, thereby reducing the vibration noise of the screw compressor.

The male rotor and the motor shaft of the traditional screw compressor are both rigid shafts, the bearings are respectively arranged at the left end and the right end of the screw rotor, and the motor rotor is of a cantilever beam supporting structure. The rotor arrangement mode has a simple structure, but the motor tooth space torque pulsation and meshing excitation generated by screw airflow load torque are mutually superposed on the same rigid shaft formed by the motor rotor and the male rotor, namely, the mutual coupling deteriorates the meshing of the male rotor and the female rotor of the screw, further aggravates the rotating speed pulsation and generates larger vibration noise. Furthermore, the cantilever beam supporting structure of the motor rotor is easy to generate dynamic eccentricity when rotating at a high speed, so that the air gap of the motor stator and the motor rotor is not uniform, unbalanced magnetic pull force is generated, and motor vibration is aggravated.

Therefore, how to overcome the defects that the rotating speed pulsation of the male rotor and the female rotor of the screw compressor is severe and the vibration noise is serious; the cantilever beam support of the motor rotor aggravates the vibration of the motor, which is a problem to be solved in the field.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a solve present screw compressor's negative and positive rotor rotational speed pulsation acutely, the serious technical problem of vibration noise provides one kind and can realize the vibration damper that static torque transmission and dynamic fluctuation moment of torsion keep apart and have this vibration damper's torsional vibration damping coupling and adopt this torsional vibration damping coupling's screw compressor. Meanwhile, the support of the motor rotor and the screw male rotor is improved, so that the dynamic eccentricity of the motor rotor is reduced, and the vibration of a compressor motor is reduced.

The utility model provides a pair of vibration damper is including parallelly connected positive rigidity elastic element and the burden rigidity elastic element who sets up, positive rigidity elastic element with burden rigidity elastic element's mounting height is the same.

Preferably, the positive stiffness element is an annular elastic element, and the negative stiffness elastic element is a disc spring; the disc spring is arranged in the inner circle of the annular elastic element.

Preferably, the positive stiffness element is an annular elastic element, and the negative stiffness elastic element is a disc spring; the annular elastic element and the disc spring are arranged in parallel.

Preferably, the ratio of the height to the thickness of the belleville springs is greater than 1.5.

Preferably, the ratio of the height to the thickness of the disc spring is 2.75.

Preferably, the annular elastic element is a rubber ring or a metal rubber ring.

The utility model also provides a torsional vibration damping coupling with the damping device, which comprises a load end connecting semi-shaft and a drive end connecting semi-shaft, wherein at least one first stress plate radially extends out of the excircle of the load end connecting semi-shaft, at least one second stress plate radially extends out of the excircle of the drive end connecting semi-shaft, and the first stress plate and the second stress plate are connected with each other to form a pair of connecting structures; at least one set of the vibration reduction device is arranged between the first stress plate and the second stress plate, and the second stress plate with the driving end connected with the half shaft firstly transmits driving force to the first stress plate through the vibration reduction device and then drives the load end connected with the half shaft to rotate.

Preferably, the second stress plate on the driving end connecting half shaft is provided with an open slot, and the first stress plate on the load end connecting half shaft is inserted into the open slot of the second stress plate to form the connecting structure.

Preferably, an open groove may be formed in the first stressed plate on the load end connecting half shaft, and the second stressed plate on the drive end connecting half shaft is inserted into the open groove of the first stressed plate to form the connecting structure.

Preferably, the connecting structure can be two, three or four pairs.

Preferably, the connecting structure connects and fixes the first and second stress plates through bolts.

The utility model discloses in addition provide an adopt torsional vibration damping coupling's screw compressor, including screw rod male rotor and electric motor rotor, electric motor rotor and screw rod male rotor segmentation set up, electric motor rotor passes through torsional vibration damping coupling with the screw rod male rotor is connected.

Preferably, the motor rotor is a simply supported beam supporting structure.

The utility model discloses adopt the segment structure setting with screw compressor's screw rod male rotor and electric motor rotor to the torsional vibration damping shaft coupling that uses to have vibration damper is with screw rod male rotor and electric motor rotor coaxial coupling, thereby makes and can realize static torque transmission and dynamic fluctuation moment of torsion isolation between electric motor rotor and the screw rod male rotor. Therefore, the mutual influence of excitation coupling and rotation speed pulsation between the motor rotor and the screw rotor can be reduced, the negative influence of motor tooth space torque fluctuation on screw rotor meshing is reduced, the screw meshing working condition is effectively improved, and vibration noise is reduced. In addition, two ends of the motor rotor of the screw compressor and two sections of the male screw rotor are respectively provided with a bearing support, namely the two sections of rotors are respectively provided with a simply supported beam support structure. Therefore, the concentricity of the two rotors is better, the dynamic eccentricity of the motor rotor is reduced, the air gap of the motor stator and the motor rotor is more uniform, the unbalanced magnetic pull force is reduced, and the vibration of the compressor motor is smaller.

Drawings

Fig. 1a is a schematic perspective view of an embodiment of the damping device of the present invention;

fig. 1b is a schematic perspective view of another embodiment of the vibration damping device of the present invention;

FIG. 2 is a cross-sectional view of the disc spring of FIG. 1a or FIG. 1 b;

fig. 3 is a sectional view of an embodiment of the screw compressor of the present invention;

fig. 4 is an exploded view of the torsional vibration damping coupling with the damping device of the present invention;

FIG. 5 is an assembly view of FIG. 4;

fig. 6 is a total stiffness characteristic curve of the damping device of the present invention.

Wherein: 1 is a screw male rotor left bearing, 2 is a screw male rotor, 3 is a screw male rotor right bearing, 4 is a motor rotor left bearing, 5 is a torsional vibration damping coupler, 6 is a motor rotor, and 7 is a motor rotor right bearing;

51 is a load end connecting half shaft, 511 is a first stress plate, 52 is a lock nut, 53 is a drive end connecting half shaft,

531 is an upper second stress plate, 532 is a lower second stress plate, 54 is a bolt, 55 is a nut, 56 is an annular elastic element,

And 57 is a disc spring.

Detailed Description

The present invention will be further described with reference to the following examples and drawings, which are not intended to limit the present invention.

As shown in fig. 1a, fig. 1b and fig. 2, in order to provide an embodiment of the damping device of the present invention, the damping device includes a positive stiffness elastic element and a negative stiffness elastic element which are arranged in parallel, and the installation heights of the positive stiffness elastic element and the negative stiffness elastic element are the same. Namely, when the device is installed, the upper planes of the positive stiffness elastic element and the negative stiffness elastic element are in the same plane; the lower planes of the positive stiffness elastic element and the negative stiffness elastic element are also in the same plane. The positive stiffness element in this embodiment is an annular elastic element 56 and the negative stiffness elastic element is a disc spring 57, as required. Referring to fig. 1a, a disc spring 57 is disposed in the inner circle of the annular elastic element 56 to form a sleeved vibration damping device. As shown in fig. 1b, a disc spring 57 and an annular elastic element 56 may be arranged in parallel to form a set of vibration damping devices. That is, the vertical distance from the lower surfaces of the annular elastic member 56 and the disc spring 57 to the upper surfaces thereof is the mounting height of the two elastic members. No matter the structure is set in a sleeving way or in a parallel way, the installation heights of the positive and negative rigidity elastic elements are required to be the same. A plurality of sets of vibration damping devices can be used together according to the requirement, and the installation heights of the plurality of sets of vibration damping devices used together need to be the same in the same way. The annular elastic member 57 may be a rubber ring or a metal rubber ring. As shown in fig. 2, the ratio of the height h to the thickness t of the disc spring 57 needs to be greater than 1.5. In this embodiment, the ratio of the height to the thickness of the disc spring 57 is 2.75. And the stiffness characteristics of the annular spring member 56 can be designed based on the torque back-calculation of the motor and screw load.

As shown in fig. 3, the utility model provides a torsional vibration damping coupling 5 with damping device is applied to the torsional vibration damping between electric motor rotor and the screw rod male rotor among the screw compressor. The utility model provides a screw compressor, its screw rod male rotor 2 and electric motor rotor 6 adopt the structure that the segmentation set up, and electric motor rotor 6 passes through the utility model provides a torsional vibration damping shaft coupling 5 and screw rod male rotor 2 coaxial coupling become an organic whole.

Referring to fig. 4 and 5, the present invention provides a torsional vibration damping coupling 5 with a vibration damping device according to a first embodiment. The torsional vibration damping coupling 5 comprises a load end connecting half shaft 51 connected with a screw male rotor 2 in the screw compressor through a key, and a drive end connecting half shaft 53 connected with a motor rotor 6 in the screw compressor through a key. To connect the load end connecting half shaft 51 with the drive end connecting half shaft 53, a first force-bearing plate 511 radially extends from the outer circumference of the load end connecting half shaft 51, and a second force-bearing plate, such as the upper second force-bearing plate 531 shown in fig. 4, radially extends from the outer circumference of the drive end connecting half shaft 53. That is, the second force-bearing plate in this embodiment is a single-piece structure, rather than the two-piece structure with open slots as shown in fig. 4. The first force-receiving plate 511 and the second force-receiving plate are connected to each other to constitute a pair of connection structures. At least one set of said vibration damping means is arranged between the first force plate 511 and the second force plate, i.e. at least one set of vibration damping means may be arranged in a nested arrangement (see fig. 1 a) or in a juxtaposed arrangement (see fig. 1 b). The specific location of the vibration damping device needs to be correspondingly located according to the rotation direction input by the driving end connecting half shaft 53. It is necessary to make the second force-bearing plate whose driving end is connected with the half shaft 53 transmit the driving force to the first force-bearing plate 511 through the damping device and then drive the load end to be connected with the half shaft 51 to rotate. That is, it is necessary to subject the damper device to pressure during the transmission to transmit the driving force. The annular elastic member 56 and the belleville springs 57 are installed at the same height and are disposed between the first force receiving plate 511 and the second force receiving plate (the second force receiving plate 531 as above) such that the annular elastic member 56 and the belleville springs 57 are simultaneously compressed when the drive shaft (the motor rotor 6) transmits torque. The negative rate characteristic is exhibited only when the negative rate elastic member, the belleville spring 57, is subjected to a compressive transfer load. When the semi-axis 53 rotation direction was connected to the drive end changed, corresponding adjustment need be made in the installation that semi-axis 53, load end were connected to the drive end, semi-axis 51 and vibration damper, only make vibration damper bear compression transmission load, set up like this and just can guarantee to realize the utility model discloses a purpose of static torque transmission and dynamic fluctuation moment of torsion isolation. For example, referring to fig. 5, the axial projection of the shaft segment of the screw male rotor 2 to the shaft segment of the motor rotor 6 is performed, the driving end connecting half shaft 53 rotates clockwise along with the motor rotor 6, and the vibration damping device sleeved by the annular elastic element 56 and the disc spring 57 is provided between the upper second force bearing plate 531 and the first force bearing plate 511. If the driving end connecting half shaft 53 rotates counterclockwise along with the motor rotor 6, the upper second force-bearing plate 531 needs to be placed under the first force-bearing plate 511 during installation, and the vibration damping device is disposed between the first force-bearing plate 511 and the upper second force-bearing plate 531. The two installation manners are to ensure that when the driving end connecting half shaft 53 inputs torque, the second force-bearing plate 531 transmits driving force to the first force-bearing plate 511 through the vibration damper, and then drives the load end connecting half shaft 51 to rotate.

As shown in fig. 4 and 5, a torsional vibration damping coupling 5 having a damping device according to a second embodiment of the present invention is provided. The torsional vibration damping coupling 5 comprises a load end connecting half shaft 51 connected with the screw male rotor 2 and a drive end connecting half shaft 53 connected with the motor rotor 6. To connect the load end connecting half shaft 51 with the drive end connecting half shaft 53, the outer circle of the load end connecting half shaft 51 radially extends at least one first force-bearing plate 511, and the outer circle of the drive end connecting half shaft 53 radially extends at least one second force-bearing plate. The first force-receiving plate 511 and the second force-receiving plate are connected to each other to form a pair of connection structures. Except that the second force-receiving plate on the drive-end connecting half shaft 53 is provided with an open groove so that it has a two-piece structure of upper and lower second force-receiving

plates

531, 532 in parallel, while the first force-receiving plate 511 on the load-end connecting half shaft 51 is inserted into the open groove formed by the upper and lower second force-receiving

plates

531, 532 and forms a connecting structure. As in the first embodiment, when the drive-end connecting half shaft 53 rotates clockwise along with the motor rotor 6, a damper device, which is provided by a ring-shaped elastic member 56 and a disc spring 57, is interposed between the upper second force-receiving plate 531 and the first force-receiving plate 511. When the driving-end connecting half shaft 53 rotates counterclockwise along with the motor rotor 6, the vibration damping device is disposed between the lower second force-bearing plate 532 and the first force-bearing plate 511. The arrangement is that no matter how the rotation direction of the motor rotor 6 is changed, the second stress plate of the driving end connecting half shaft 53 can firstly transmit driving force to the first stress plate 511 through the vibration damping device, and then the second stress plate drives the load end connecting half shaft 51 to rotate. The first force-bearing plate 511 on the load-end connecting half shaft 51 may also be provided with a two-piece structure having an open slot, and the second force-bearing plate on the drive-end connecting half shaft is a one-piece structure and is inserted into the open slot of the first force-bearing plate 511 to form the connecting structure. The installation of the damping device is required to follow the principle that the damping device is subjected to pressure to transmit driving force during the transmission process.

As shown in fig. 4, in the second embodiment of the torsional vibration damping coupling 5 having a vibration damping device, four first force-receiving plates 511 are provided on the load-side connecting half shaft 51 and are arranged uniformly in the circumferential direction of the outer circle of the load-side connecting half shaft 51, and four upper and lower second force-receiving

plates

531, 532 of a two-plate structure are provided on the corresponding drive-end connecting half shaft 53. The first force receiving plate 511 and the upper and lower second

force receiving plates

531 and 532 may be connected to each other to form four pairs of connection structures. According to the condition of transmitting the driving torque, the connecting structure can also be symmetrically arranged or uniformly distributed with two pairs or three pairs of pairs. The first stress plate 511 and the upper and lower

second stress plates

531, 532 of the connecting structure are provided with screw holes, and the first and second stress plates can be connected and fixed through bolts 54 and nuts 55.

As shown in fig. 3 to have the utility model provides a torsional vibration damping coupling 5's helical-lobe compressor's preferred embodiment, its screw rod male rotor 2 and electric motor rotor 6 adopt the structure that the segmentation set up, and electric motor rotor 6 is through having the utility model provides a damping device's torsional vibration damping coupling 5 and screw rod male rotor 2 coaxial coupling become integrative. Importantly, the motor rotor 6 and the screw male rotor 2 are both simply supported beam supporting structures. Namely, a screw left bearing 1 and a screw right bearing 3 are respectively arranged at two ends of the screw male rotor 2, and a motor left bearing 4 and a motor right bearing 7 are respectively arranged at two ends of the motor rotor 6. Because the two ends of the screw compressor motor rotor 6 and the two sections of the screw male rotor 2 both adopt a simply supported beam supporting structure. The concentricity of the two rotors is better, the dynamic eccentricity of the motor rotor 6 is reduced, and meanwhile, the air gap of the motor stator and rotor 6 is more uniform, the unbalanced magnetic tension is reduced, so that the vibration of the screw compressor motor is smaller.

As shown in fig. 3, 4 and 5, the torque damping coupling 5 provided by the present invention is used in a semi-open type machine. That is, a plurality of sections of the engine bodies are connected through flanges in the axial direction, and the half shafts are connected through a coupling device. The utility model discloses a torsional vibration damping shaft coupling 5's installation order does: firstly, a load end connecting half shaft 51 is installed at the shaft end of the screw male rotor 2, and the load end connecting half shaft 51 is locked at the shaft head of the screw male rotor 2 through a lock nut 52 to prevent axial movement. The load end connecting half shaft 51 and the screw male rotor 2 are circumferentially defined by a key connection. Then, the first force receiving plate 511 is inserted between the upper and lower second

force receiving plates

531, 532 on the drive end connecting half shaft 53, while the annular elastic member 56 and the disc spring 57 are mounted between the upper second force receiving plate 531 and the first force receiving plate 511, the upper and lower second

force receiving plates

531, 532, the annular elastic member 56 and the disc spring 57 are connected and fixed by the bolts 54 and the nuts 55. That is, both the load-end connecting half shaft 51 and the drive-end connecting half shaft 53 in the circumferentially symmetrical direction are fixed by the above-described operation. And finally, aligning and approaching the shaft section of the load side screw male rotor 2 provided with the torque damping coupler 5 and the shaft section of the drive side motor rotor 6, inserting the shaft section of the motor rotor 6 into an inner hole of the drive end connecting half shaft 53, realizing circumferential limitation by key connection of the shaft section of the motor rotor 6 and the drive end connecting half shaft 53, and fixing an external machine body through a flange. Through the installation, the load end connecting half shaft 51 is axially locked and limited through the lock nut 52, the drive end connecting half shaft 53 is fixedly connected with the load end connecting half shaft 51 through the bolt 54 and the nut 55, and therefore the drive end connecting half shaft 53 is effectively restrained.

The utility model provides a torsional vibration damping shaft coupling 5 mainly used with damping device reduces the influence that motor torque fluctuation and reduction of rotational speed fluctuation caused to the screw rod meshing to the transmission of screw rod rotor system. Specifically, this is achieved by providing an annular elastic element 56 having a positive stiffness characteristic and a disc spring 57 having a negative stiffness characteristic between the drive end half shaft and the load end half shaft.

As shown in fig. 6, the present invention provides a damping device having a total stiffness characteristic curve. The positive stiffness characteristic of the annular resilient element 56 is shown in dashed lines in fig. 6. The linear rigidity is approximate in a quite wide deformation range, namely, the characteristic of positive rigidity is always obtained; and the stiffness characteristic curve of the disc spring 57 having a height to thickness ratio of more than 1.5, as shown by the two-dot chain line in fig. 6. When the torque is smaller and the deformation deflection of the disc spring 57 is smaller, the positive stiffness characteristic is also shown, as shown by the section 1-2 in the curve; the total stiffness characteristic of the parallel connection of the positive and negative stiffness elements is shown by the solid line in fig. 6, and the total stiffness characteristic corresponding to this moment is an approximate linear stiffness, as shown by the section "a-B" thereof. As the load increases, the annular resilient member 56 and the belleville springs 57 compress more, and the stiffness of the belleville springs 57 exhibit a negative stiffness characteristic as shown in the "2-3" segment of the curve. At this time, the total stiffness characteristic curve of the annular elastic member 56 and the disc spring 57 is superimposed, as indicated by the section "B-C" thereof. The equilibrium position of the damping device under load is usually designed to be in the vicinity of the corresponding midpoint "O" on the "B-C" curve. And point "O" is the midpoint of the negative stiffness resilient element 57 in the segment of its curve "2-3". The load corresponding to the section of the total stiffness characteristic curve B-C of the O point deflection is the balance load or is called the static load, and the static load is transmitted by the damping device. The arrangement of the annular resilient element 56 in parallel with the belleville springs 57 results in a total stiffness characteristic curve with relatively wide deflection range near the equilibrium position with small load variations.

As can be seen from FIG. 6, the positive and negative stiffness element parallel connection vibration damper provided by the utility model has the rigidity characteristic when a small amount of deformation is carried, and can transmit increased static torque at the moment if the section A-B of the total stiffness characteristic curve is shown; when the vibration damping device is positioned in a section B-C of a total stiffness characteristic curve along with the increase of the load, if dynamic fluctuating torque occurs, the dynamic fluctuating torque is absorbed by the flexibility characteristic of the vibration damping device with the positive stiffness element and the negative stiffness element connected in parallel, namely the vibration damping device deforms greatly at the moment, and the bearing cannot be increased correspondingly, so that the transmission of the dynamic fluctuating torque can be isolated. Namely, the rigidity is very small in a section of a nearly straight B-C curve of a total rigidity characteristic curve, the load capacity changes little along with the increase of the deflection, and the deflection equivalent to the fluctuation allows the elastic element with positive and negative rigidity connected in parallel to compensate through deformation. Because the load change is small, the transmitted torque is stable, and the vibration reduction effect is achieved, namely, the fluctuation torque from the driving shaft to the load shaft is isolated, so that the influence of the motor tooth space torque pulsation on the screw meshing is reduced, the meshing stability of the screw is improved, and the vibration noise is reduced; in the section "B-C" of the overall stiffness characteristic, the damping device can be used to transmit the static load.

The utility model discloses a torsional vibration damping coupling with vibration damper is with screw compressor's positive rotor of screw rod and electric motor rotor coaxial coupling to make and to realize the purpose that static moment of torsion transmission and dynamic fluctuation moment of torsion kept apart between electric motor rotor and the positive rotor of screw rod. The static rigidity of the rotor is high, which is beneficial to transmitting torque, but the rigidity is high, which is not beneficial to vibration isolation, and the rigidity is low, which is beneficial to vibration isolation. The utility model discloses a parallelly connected setting of positive negative stiffness component realizes reaching balanced back at drive shaft and load axle torsional displacement, and static moment of torsion is undertaken by positive stiffness component to utilize the effect of negative stiffness component, make at the balanced position holistic damping device has less rigidity, so that the undulant moment of torsion keeps apart effectually. Therefore, the mutual influence of excitation coupling and rotating speed pulsation between the motor rotor and the screw rotor can be reduced, the negative influence of motor tooth-groove torque fluctuation on screw rotor meshing is reduced, the screw meshing working condition is effectively improved, and vibration noise is reduced.

The above description is only an embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. The damping device is characterized by comprising a positive stiffness elastic element and a negative stiffness elastic element which are arranged in parallel, wherein the positive stiffness elastic element and the negative stiffness elastic element are the same in installation height; the positive stiffness element is an annular elastic element, and the negative stiffness elastic element is a disc spring; the disc spring is arranged in the inner circle of the annular elastic element;

alternatively, the annular elastic element and the disc spring are juxtaposed.

2. The vibration damping device of claim 1 wherein the ratio of the height to the thickness of the disc spring is greater than 1.5.

3. The vibration damping device of claim 2 wherein the ratio of the height to the thickness of the disc spring is 2.75.

4. The vibration damping device according to claim 1, wherein the annular elastic member is a rubber ring or a metal rubber ring.

5. A torsional vibration damping coupler is characterized by comprising a load end connecting half shaft and a drive end connecting half shaft, wherein at least one first stress plate radially extends out of the excircle of the load end connecting half shaft, at least one second stress plate radially extends out of the excircle of the drive end connecting half shaft, and the first stress plate and the second stress plate are connected with each other to form a pair of connecting structures; at least one set of vibration damper according to any one of claims 1 to 4 is arranged between the first and second force-bearing plates, and the second force-bearing plate with the driving end connected with the half shaft firstly transmits driving force to the first force-bearing plate through the vibration damper and then drives the load end connected with the half shaft to rotate.

6. The torsional vibration damping coupling of claim 5 in which the second force plate on the drive end coupling half shaft is provided with an open slot and the first force plate on the load end coupling half shaft is inserted into the open slot of the second force plate to form the coupling structure.

7. The torsional vibration damping coupling of claim 5 in which a first force plate on the load end coupling half shaft is provided with an open slot and a second force plate on the drive end coupling half shaft is inserted into the open slot of the first force plate to form the coupling structure.

8. The torsional vibration damping coupling of claim 5 in which said connecting structure is two, three or four pairs.

9. The torsional vibration damping coupling of claim 5 in which said connecting structure connects and secures said first and second force-bearing plates by bolts.

10. A screw compressor comprising a male screw rotor and a motor rotor, wherein the motor rotor and the male screw rotor are arranged in sections and the motor rotor is connected to the male screw rotor by a torsional vibration damping coupling according to any one of claims 5 to 9.

11. The screw compressor according to claim 10, wherein the motor rotor is a simple beam support structure.