CN203717346U - Single-cylinder rotary compressor and dual-cylinder rotary compressor - Google Patents

Abstract

The utility model discloses a single-cylinder rotary compressor and a dual-cylinder rotary compressor. The single-cylinder rotary compressor comprises an air cylinder, an upper bearing, a lower bearing and a plurality of first screws, wherein a plurality of first threaded holes are formed in the air cylinder; the upper bearing is arranged on the air cylinder; the lower bearing is arranged under the air cylinder; the first screws are respectively in one-to-one correspondence with the first threaded holes, and part of the first screws penetrate through the upper bearing and are matched with part of the first threaded holes to fix the upper bearing on the air cylinder; the rest first screws penetrate through the lower bearing and are matched with the rest threaded holes to fix the lower bearing on the air cylinder. According to the single-cylinder rotary compressor, the resistance of the air cylinder to a lateral force acting on the air cylinder is increased, the connection reliabilities between the upper bearing and the air cylinder as well as the air cylinder and the lower bearing can be improved, and the compression actions of the screws to the air cylinder can be resisted, so that the distortion of a slip sheet groove of the air cylinder is reduced.

Description

Single cylinder rotary compressor and duplex-cylinder rotary compressor

Technical field

The utility model relates to refrigerating field, especially relates to a kind of single cylinder rotary compressor and duplex-cylinder rotary compressor.

Background technique

Cylinder flattening design is to improve one of of paramount importance means of rotary compressor efficiency, and the cylinder of the design of flattening is simultaneously little for the discharge capacity of the Novel cooling mediums such as carbon dioxide.Wherein cylinder flattening design has higher requirement to the reliability of the compression member portion of rotary compressor, traditional Placement is that first group of screw links together upper bearing (metal) and cylinder, second group of screw links together lower bearing and cylinder, first group of screw and second group of screw upwards have identical position, hole distribution week, and the screw at place, same holes position shares a tapped hole on cylinder, when cylinder cylinder high hour, in above-mentioned Placement, cylinder tapped hole and screw engagement button number are not enough, worm tooth stress is concentrated aggravation, easily produce worm tooth fracture failure.

Settling mode in correlation technique is to change cylinder tapped hole into through hole, one group of screw is connected to the tapped hole on upper bearing (metal) by lower bearing, cylinder, this just causes the ability degradation of cylinder lateral force resisting, as the pressing-in force that cylinder is pressed into conical pipe in cylinder suction port in chamber gas force and compressor assembly process is by compression done the used time, cylinder and upper bearing (metal) or lower bearing easily misplace, now this solution also can cause vane slot distortion to worsen, compressor operation reliability decrease.

Model utility content

The utility model is intended to solve at least to a certain extent one of technical problem in correlation technique.

For this reason, an object of the present utility model is to propose a kind of single cylinder rotary compressor, can improve the connection reliability between upper bearing (metal) and cylinder, cylinder and lower bearing.

Another object of the present utility model is to propose a kind of duplex-cylinder rotary compressor, reduces the torsional deformation of the vane slot of the first cylinder.

According to single cylinder rotary compressor of the present utility model, comprising: cylinder, described cylinder is provided with a plurality of the first tapped holes; Upper bearing (metal), described upper bearing (metal) be located at described cylinder above; Lower bearing, described lower bearing be located at described cylinder below; A plurality of the first screws, described a plurality of the first screw respectively with described a plurality of the first tapped holes corresponding matching one by one, the part in described a plurality of the first screws coordinates that with a part for described a plurality of the first tapped holes described upper bearing (metal) is fixed on described cylinder through described upper bearing (metal); Remaining part in described a plurality of the first screw coordinates that with the remaining part in described a plurality of the first tapped holes described lower bearing is fixed on described cylinder through described lower bearing.

According to single cylinder rotary compressor of the present utility model, by making the part in a plurality of the first screws coordinate that with a part for a plurality of the first tapped holes upper bearing (metal) is fixed on cylinder through upper bearing (metal).Remaining part in a plurality of the first screws coordinates that with the remaining part in a plurality of the first tapped holes lower bearing is fixed on cylinder through lower bearing, thereby improved cylinder to acting on the resistivity of the lateral force on cylinder, can improve the connection reliability between upper bearing (metal) and cylinder, cylinder and lower bearing, and can resist its pressuring action to cylinder of the first screw, the torsional deformation of the vane slot of cylinder is reduced.

In addition, according to the single cylinder rotary compressor of the utility model above-described embodiment, can also there is following additional technical characteristics:

In embodiments more of the present utility model, on described cylinder, be also provided with the first screwing through hole, described single cylinder rotary compressor also comprises the second screw, and described the second screw tightens together described upper bearing (metal), described cylinder and described lower bearing through the first screwing through hole on described cylinder.

According to embodiments more of the present utility model, the length of action L described in each between the first screw and corresponding described the first tapped hole meets following formula:

$L\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of described the first screw, and d is the screw thread nominal diameter of described the first screw, σ _sfor the yield strength of described the first screw, K is the first screw and corresponding moment coefficient corresponding to described the first tapped hole described in each, and K is limited by following formula:

Wherein, d ₂for the effective diameter of thread of described the first screw, for the lead angle of described the first screw, ρ _vfor the screw thread equivalent friction angle of described the first screw, μ is the friction factor between head and the supporting surface contacting with it of described the first screw, D _wand d ₀be respectively the head of described the first screw and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of described the first screw.Thereby can guarantee to there is enough joggle numbers between the first tapped hole and corresponding the first screw, with the reliability of guaranteeing to be threaded.

At preferred embodiment of the present utility model, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the first tapped holes of described cylinder.Thereby it is excessive to avoid influencing each other between each first tapped hole, guarantees the reliability being threaded.

In examples more of the present utility model, a described part for described a plurality of the first screws and the described remaining part of described a plurality of the first screws are interspersed.

According to duplex-cylinder rotary compressor of the present utility model, comprising: the first cylinder and the second cylinder, described the first cylinder is positioned at the top of described the second cylinder, and described the first cylinder is provided with a plurality of the second tapped holes; Central diaphragm, described central diaphragm is located between described the first cylinder and described the second cylinder; Upper bearing (metal), described upper bearing (metal) be located at described the first cylinder above; Lower bearing, described lower bearing be located at described the second cylinder below; A plurality of the 3rd screws, described a plurality of the 3rd screw respectively with described a plurality of the second tapped holes corresponding matching one by one, a part in described a plurality of the 3rd screw coordinates with the part in described a plurality of the second tapped holes through described upper bearing (metal), and the remaining part in described a plurality of the 3rd screws coordinates with the remaining part in described a plurality of the second tapped holes through described lower bearing, the second cylinder and central diaphragm.

According to duplex-cylinder rotary compressor of the present utility model, by the part in a plurality of the 3rd screws is coordinated with the part in a plurality of the second tapped holes through upper bearing (metal), remaining part in a plurality of the 3rd screws is through lower bearing, the second cylinder and central diaphragm coordinate with the remaining part in a plurality of the second tapped holes, thereby can improve the first cylinder to acting on the resistivity of the lateral force on the first cylinder, guarantee the connection reliability between the first cylinder and upper bearing (metal), and guaranteed the first cylinder, central diaphragm, connection reliability between the second cylinder and lower bearing, be conducive to reduce the torsional deformation of the vane slot of the first cylinder simultaneously.

In addition, according to the duplex-cylinder rotary compressor of the utility model above-described embodiment, can also there is following additional technical characteristics:

In embodiments more of the present utility model, the length of action L1 described in each between the 3rd screw and corresponding described the second tapped hole meets following formula:

$L1\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of described the 3rd screw, and d is the screw thread nominal diameter of described the 3rd screw, σ _sfor the yield strength of described the 3rd screw, K is the 3rd screw and corresponding moment coefficient corresponding to described the second tapped hole described in each, and K is limited by following formula:

Wherein, d ₂for the effective diameter of thread of described the 3rd screw, for the lead angle of described the 3rd screw, ρ _vfor the screw thread equivalent friction angle of described the 3rd screw, μ is the friction factor between head and the supporting surface contacting with it of described the 3rd screw, D _wand d ₀be respectively the head of described the 3rd screw and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of described the 3rd screw.Thereby guarantee to there is enough joggle numbers between the second tapped hole on the first cylinder and corresponding the 3rd screw, and then guarantee the reliability that is threaded.

In preferred embodiment of the present utility model, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the second tapped holes of described the first cylinder.Thereby by guaranteeing the wall thickness between every two the second tapped holes on the first cylinder, avoid influencing each other between each second tapped hole excessive, improve the reliability being threaded.

In examples more of the present utility model, the described remaining part of a described part for described a plurality of the 3rd screws and described a plurality of the 3rd screws is interspersed.

According to embodiments more of the present utility model, described the second cylinder is provided with a plurality of the 3rd tapped holes, described duplex-cylinder rotary compressor also comprises a plurality of the 4th screws, described a plurality of the 4th screw respectively with described a plurality of the 3rd tapped holes corresponding matching one by one, a part in described a plurality of the 4th screw coordinates with the part in described a plurality of the 3rd tapped holes through described lower bearing, and the remaining part in described a plurality of the 4th screws coordinates with the remaining part in described a plurality of the 3rd tapped holes through described upper bearing (metal), described the first cylinder and described central diaphragm.

According to the utility model embodiment's duplex-cylinder rotary compressor, by the part in a plurality of the 4th screws is coordinated with the part in a plurality of the 3rd tapped holes through lower bearing, remaining part in a plurality of the 4th screws is through upper bearing (metal), the first cylinder and central diaphragm coordinate with the remaining part in a plurality of the 3rd tapped holes, thereby can improve the second cylinder to acting on the resistivity of the lateral force on the second cylinder, guarantee the connection reliability between the second cylinder and lower bearing, and guaranteed upper bearing (metal), the first cylinder, connection reliability between central diaphragm and the second cylinder, be conducive to reduce the torsional deformation of the vane slot of the second cylinder simultaneously.

According to embodiments more of the present utility model, on described the first cylinder, be also provided with the second screwing through hole, described duplex-cylinder rotary compressor also comprises the 5th screw, and described the 5th screw tightens together described upper bearing (metal), described the first cylinder and described central diaphragm through the second screwing through hole on described the first cylinder.

In embodiments more of the present utility model, the length of action L2 described in each between the 4th screw and corresponding described the 3rd tapped hole meets following formula:

$L2\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of described the 4th screw, and d is the screw thread nominal diameter of described the 4th screw, σ _sfor the yield strength of described the 4th screw, K is the 4th screw and corresponding moment coefficient corresponding to described the 3rd tapped hole described in each, and K is limited by following formula:

Wherein, d ₂for the effective diameter of thread of described the 4th screw, for the lead angle of described the 4th screw, ρ _vfor the screw thread equivalent friction angle of described the 4th screw, μ is the friction factor between head and the supporting surface contacting with it of described the 4th screw, D _wand d ₀be respectively the head of described the 4th screw and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of described the 4th screw.Thereby guarantee to there is enough joggle numbers between the 3rd tapped hole on the second cylinder and corresponding the 4th screw, and then guarantee the reliability that is threaded.

In preferred embodiment of the present utility model, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the 3rd tapped holes of described the second cylinder.Thereby by guaranteeing the wall thickness between every two the 3rd tapped holes on the second cylinder, avoid influencing each other between each the 3rd tapped hole excessive, improve the reliability being threaded.

According to embodiments more of the present utility model, on described the second cylinder, be also provided with the 3rd screwing through hole, described duplex-cylinder rotary compressor also comprises the 6th screw, and described the 6th screw tightens together described lower bearing, described the second cylinder and described central diaphragm through the 3rd screwing through hole on described the second cylinder.

According to duplex-cylinder rotary compressor of the present utility model, comprising: the first cylinder and the second cylinder, described the first cylinder is positioned at the top of described the second cylinder, and described the second cylinder is provided with a plurality of the 3rd tapped holes; Central diaphragm, described central diaphragm is located between described the first cylinder and described the second cylinder; Upper bearing (metal), described upper bearing (metal) be located at described the first cylinder above; Lower bearing, described lower bearing be located at described the second cylinder below; A plurality of the 4th screws, a plurality of described the 4th screws respectively with described a plurality of the 3rd tapped holes corresponding matching one by one, a part in described a plurality of the 4th screw coordinates with the part in described a plurality of the 3rd tapped holes through described lower bearing, and the remaining part in described a plurality of the 4th screws coordinates with the remaining part in described a plurality of the 3rd tapped holes through described upper bearing (metal), described the first cylinder and described central diaphragm.

According to duplex-cylinder rotary compressor of the present utility model, by the part in a plurality of the 4th screws is coordinated with the part in a plurality of the 3rd tapped holes through lower bearing, remaining part in a plurality of the 4th screws is through upper bearing (metal), the first cylinder and central diaphragm coordinate with the remaining part in a plurality of the 3rd tapped holes, thereby can improve the second cylinder to acting on the resistivity of the lateral force on the second cylinder, guarantee the connection reliability between the second cylinder and lower bearing, and guaranteed upper bearing (metal), the first cylinder, connection reliability between central diaphragm and the second cylinder, be conducive to reduce the torsional deformation of the vane slot of the second cylinder simultaneously.

In addition, according to the duplex-cylinder rotary compressor of the utility model above-described embodiment, can also there is following additional technical characteristics:

In embodiments more of the present utility model, the length of action L2 described in each between the 4th screw and corresponding described the 3rd tapped hole meets following formula:

$L2\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of described the 4th screw, and d is the screw thread nominal diameter of described the 4th screw, σ _sfor the yield strength of described the 4th screw, K is the 4th screw and corresponding moment coefficient corresponding to described the 3rd tapped hole described in each, and K is limited by following formula:

Wherein, d ₂for the effective diameter of thread of described the 4th screw, for the lead angle of described the 4th screw, ρ _vfor the screw thread equivalent friction angle of described the 4th screw, μ is the friction factor between head and the supporting surface contacting with it of described the 4th screw, D _wand d ₀be respectively the head of described the 4th screw and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of described the 4th screw.Thereby guarantee to there is enough joggle numbers between the 3rd tapped hole on the second cylinder and corresponding the 4th screw, and then guarantee the reliability that is threaded.

In preferred embodiment of the present utility model, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the 3rd tapped holes of described the second cylinder.Thereby by guaranteeing the wall thickness between every two the 3rd tapped holes on the second cylinder, avoid influencing each other between each the 3rd tapped hole excessive, improve the reliability being threaded.

In embodiments more of the present utility model, on described the second cylinder, be also provided with the 3rd screwing through hole, described duplex-cylinder rotary compressor also comprises the 6th screw, and described the 6th screw tightens together described lower bearing, described the second cylinder and described central diaphragm through the 3rd screwing through hole on described the second cylinder.

Accompanying drawing explanation

Fig. 1 is according to the schematic diagram of the utility model embodiment's single cylinder rotary compressor;

Fig. 2 is the plan view that the compression member portion attachment screw in the single cylinder rotary compressor shown in Fig. 1 distributes;

Fig. 3 is the free-body diagram of the cylinder in the single cylinder rotary compressor shown in Fig. 1 while being subject to lateral forces;

Fig. 4 is cylinder vane slot local pressure and the vane slot torsional deformation schematic diagram in the single cylinder rotary compressor shown in Fig. 1;

Fig. 5 is screw connecting structure and sizing specification figure;

Fig. 6 is cylinder tapped hole force simplified plotted curve vertically;

Fig. 7 is minimum wall thickness (MINI W.) h plotted curve between tapped hole radial deformation-tapped hole;

Fig. 8 is according to the schematic diagram of an embodiment's of the utility model duplex-cylinder rotary compressor;

Fig. 9 is the plan view distributing for the compression member portion attachment screw in the duplex-cylinder rotary compressor shown in Fig. 8;

Figure 10 is according to the schematic diagram of the compression member portion major component in another embodiment's of the utility model duplex-cylinder rotary compressor;

Figure 11 is the plan view that the compression member portion attachment screw shown in Figure 10 distributes.

Reference character:

Single cylinder rotary compressor 100, duplex-cylinder rotary compressor 200, cylinder 1, upper bearing (metal) 2, lower bearing 3, the sub-screw 4a of the first screw 4, first, the second sub-screw 4b, duplex-cylinder rotary compressor 200, the first cylinder 5, the second cylinder 6, central diaphragm 7, the 3rd screw the 10, the 3rd sub-screw 10a, the 4th sub-screw 10b, the 4th screw the 11, the 5th sub-screw 11a, the 6th sub-screw 11b, conical pipe 12, suction port 13, vane slot 14

Embodiment

Describe embodiment of the present utility model below in detail, described embodiment's example is shown in the drawings, and wherein same or similar label represents same or similar element or has the element of identical or similar functions from start to finish.Below by the embodiment who is described with reference to the drawings, be exemplary, be intended to for explaining the utility model, and can not be interpreted as restriction of the present utility model.

Below with reference to Fig. 1-Fig. 7, describe according to the utility model embodiment's single cylinder rotary compressor 100, it should be noted that, the working principle of single cylinder rotary compressor 100 etc. is those skilled in the art to be known, and is not just described in detail here.

Single cylinder rotary compressor 100 according to the utility model embodiment, comprising: cylinder 1, upper bearing (metal) 2, lower bearing 3 and a plurality of the first screw 4, wherein, cylinder 1, upper bearing (metal) 2 and lower bearing 3 form the compression member portion of single cylinder rotary compressor 100.Cylinder 1 is provided with a plurality of the first tapped holes (scheming not shown), is also provided with for assembling the vane slot 14 of slide plate (scheming not shown) and for assembling the suction port 13 of conical pipe 12 on cylinder 1.Upper bearing (metal) 2 be located at cylinder 1 above.Lower bearing 3 be located at cylinder 1 below, upper bearing (metal) 2, cylinder 1 and lower bearing 3 limit the active chamber of cylinder 1.

A plurality of the first screws 4 respectively with a plurality of the first tapped holes corresponding matching one by one, the part in a plurality of the first screws 4 coordinates that with a part for a plurality of the first tapped holes upper bearing (metal) 2 is fixed on cylinder 1 through upper bearing (metal) 2.Remaining part in a plurality of the first screws 4 coordinates that with the remaining part in a plurality of the first tapped holes lower bearing 3 is fixed on cylinder 1 through lower bearing 3.That is to say, first tapped hole coordinates with first screw 4, the first screw 4 that connects upper bearing (metal) 2 and cylinder 1 is connected to the first tapped hole on cylinder 1, and this first tapped hole does not coordinate with other any first screws 4, the first screw 4 that connects lower bearing 3 and cylinder 1 is connected to the first tapped hole on cylinder 1, and this first tapped hole does not coordinate with other any first screws 4.

Particularly, a plurality of the first screws 4 comprise at least one first sub-screw 4a and at least one second sub-screw 4b, wherein at least one first sub-screw 4a coordinates that with part the first tapped hole in a plurality of the first tapped holes upper bearing (metal) 2 is fixed on cylinder 1 respectively, and at least one second sub-screw 4b coordinates that with remaining part the first tapped hole in a plurality of the first tapped holes lower bearing 3 is fixed on cylinder 1 respectively.Wherein, the first tapped hole that each the first sub-screw 4a is corresponding does not coordinate with other any screws 4, and the first tapped hole that each the second sub-screw 4b is corresponding does not coordinate with other any screws 4.As shown in Figure 2, what in figure, solid line represented is the first sub-screw 4a from the first urgent screw 4(of upper bearing (metal) 2), what in figure, dotted line represented is to be the second sub-screw 4b from the first urgent screw 4(of lower bearing 3), from the urgent screw 4 of upper bearing (metal) 2 with from the first urgent screw 4 of lower bearing 3, be all connected to difference the first tapped hole cylinder 1, thereby can meet the highly little requirement of cylinder 1 of single cylinder rotary compressor 100.

In the example of Fig. 2, the remaining part of a part for a plurality of the first screws 4 and a plurality of the first screws 4 is interspersed.That is to say, at least one first sub-screw 4a and at least one second sub-screw 4b are interspersed.

After the long-time shutdown of air-conditioning system, the refrigerant in system and the lubricant oil in compressor will be deposited on compressor bottom, even progress in the active chamber of cylinder 1, and now system starts and may form " hydraulic compression ".In compressor operating, during in bad working environments such as " hydraulic compressions ", the reliability that the compression member portion of compressor connects seems particularly important, otherwise may cause the dislocation of cylinder 1 and upper bearing (metal) 2 and lower bearing 3, causes compressor card cylinder and scraps.The Placement of relatively traditional cylinder through hole, the ability that the present embodiment cylinder 1 bears lateral force strengthens and can reach more than 50%.Free-body diagram when being illustrated in figure 3 the present embodiment cylinder 1 and being subject to lateral forces.In cylinder 1 operation process, be subject to gas force or be pressed into the lateral force F such as power when conical pipe 12 is pressed into the suction port 13 of cylinder 1 in assembly process _{side direction}do the used time, remove upper bearing (metal) 2 and lower bearing 3 and provide respectively frictional force f at cylinder 1 end face _{upper bearing (metal)}and f _{lower bearing}outward, relatively traditional cylinder 1 through hole mode, the screw 4 that is respectively connected to the tapped hole of cylinder 1 in the present embodiment also will provide directed force F _screwthereby, greatly strengthened the reliability that compression member portion connects.

On the other hand, vane slot 14 parts of cylinder 1 are subject to the impacting force of upper bearing (metal) 2 and 3 pairs of cylinders 1 of lower bearing, make vane slot 14 both sides produce torsional deformation, especially vane slot 14 suction side due to the weakening of 13 pairs of local stiffness of suction port, torsional deformation is even more serious.The torsional deformation of vane slot 14 both sides of cylinder 1 has reduced the reliability of vane motion, and makes the frictional force of slide plate both sides or leak to increase.Fig. 4 is vane slot 14 local pressures and the vane slot 14 torsional deformation schematic diagram of the present embodiment cylinder 1.The relatively design of industry cylinder through hole, according to the utility model embodiment's single cylinder rotary compressor 100 by the tapped hole that connects the first screw 4 is arranged on cylinder 1, the directed force F of the tapped hole of 4 pairs of cylinders 1 of the first screw _{upper bearing (metal) screw}, F _{lower bearing screw}respectively with the impacting force F of upper bearing (metal) 2 and 3 pairs of cylinders 1 of lower bearing _{upper bearing (metal)}and F _{lower bearing}opposite direction, can resist its pressuring action to cylinder 1, and the torsional deformation of the vane slot 14 of cylinder 1 is reduced.

According to the utility model embodiment's single cylinder rotary compressor 100, by making the part in a plurality of the first screws 4 coordinate that with a part for a plurality of the first tapped holes upper bearing (metal) 2 is fixed on cylinder 1 through upper bearing (metal) 2.Remaining part in a plurality of the first screws 4 coordinates that with the remaining part in a plurality of the first tapped holes lower bearing 3 is fixed on cylinder 1 through lower bearing 3, thereby improved 1 pair of resistivity that acts on the lateral force on cylinder 1 of cylinder, can improve the connection reliability between upper bearing (metal) 2 and cylinder 1, cylinder 1 and lower bearing 3, and can resist first screw 4 its pressuring actions to cylinder 1, the torsional deformation of the vane slot 14 of cylinder 1 is reduced.

Fig. 5 is the first screw 4 linkage structures and sizing specification figure, and the supporting surface wherein contacting with the first screw 4 heads is likely baffler or bearing surface, depending on actual conditions.In compressor industry, generally by torque spanner method, control the first screw 4 pretightening forces, urgent wrench torque T is used for overcoming screw pair resisting moment T ₁and the first end-face friction moment T between screw 4 heads and supporting surface ₂:

Wherein, F is screw pretightening force, and d is the screw thread nominal diameter of the first screw 4, d ₂be the effective diameter of thread of the first screw 4, be the lead angle of the first screw 4, ρ _vbe the screw thread equivalent friction angle of the first screw 4, μ be the first screw 4 heads with the supporting surface contacting with it between friction factor, D _wand d ₀the external diameter and the internal diameter that are respectively the first screw 4 heads and the circular contact area of the supporting surface formation contacting with it, as Fig. 5, if when contact area outward edge is non-circular, can be converted to actual outward edge shape the circle of homalographic, obtains equivalent D _wcalculus of approximation.K is the first tapped hole of cylinder 1 and the moment coefficient of the first screw 4 correspondences, by formula (1), can be obtained:

For single line, count screw thread, lead angle with pitch P and effective diameter of thread d ₂pass be:

Screw thread equivalent friction angle ρ _vwith screw thread equivalent friction factor μ _vpass be:

ρ _v=arctanμ _v (4)

For convenience of description, as shown in Figure 5, a circle screw thread of initial point O place engagement is defined as to the 1st button thread engagement, along X-axis direction thread engagement sequence number, increases progressively successively, L is the first screw 4 and cylinder 1 first tapped hole length of action.After the first screw 4 is urgent, the 1st buckles the stressed maximum of screw thread, and along with the increase of thread engagement sequence number, each detains stressed non-linear the reducing of screw thread.Simplify in analysis, can think and respectively detain the stressed linear change of screw thread, in worm tooth carrying inefficacy decision analysis, have higher precision, each worm tooth shearing stress of linear simplifiation stress model and the contrast of actual shearing stress are as shown in Figure 6.The first screw 4 be positioned at X=L free surface place worm tooth root shearing stress be 0, the first screw 4 to be positioned at the axial internal force in initial point O place be the first screw 4 pretightening force F, according to linear simplifiation stress model, can obtain:

$F={\∫}_0^L\mathrm{\πd\τ}\left(x\right)\mathrm{dx}=\frac{1}{2}\mathrm{\πdL\τ}\left(0\right)---\left(5\right)$

Wherein, τ (0) is that in linear simplifiation stress model, screw thread is positioned at initial point O place shearing stress.Worm tooth root is in three-dimensional stress state, but the first tapped bore is to much smaller compared with axial stress with circumferential stress, according to the 3rd theory of strength,

Worm tooth root maximum shear stress must not surpass the maximum shear stress [τ] that material allows:

${\mathrm{\τ}}_{\max }=\mathrm{n\τ}\left(0\right)\≤\left[\mathrm{\τ}\right]=\frac{{\mathrm{\σ}}_s}{2}---\left(6\right)$

Wherein, σ _sbe the yield strength of the first screw 4, the safety coefficient of n for considering that worm tooth root stress is concentrated and aforesaid stresses state reduction is introduced, gets 2.The first tapped hole that combined type (1), (5), (6) can obtain on cylinder 1 should meet with the length of action L of the first screw 4 being connected with this first tapped hole:

$L\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}---\left(7\right)$

Particularly, in the present embodiment, adopt M6 single line to count coarse thread design, the first screw semi-finals degree grade is 12.9, and urgent moment T is 15Nm, and length of thread engagement (LE) is calculated as table 1.The present embodiment guarantees to be threaded to have enough joggle numbers by above-mentioned check calculating, effectively avoids worm tooth fracture failure.

Table 1

In other words, in the embodiment of model utility, the length of action L between each first screw 4 and corresponding the first tapped hole meets following formula:

$L\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of the first screw 4, and d is the screw thread nominal diameter of the first screw 4, σ _sbe the yield strength of the first screw 4, K is each first screw 4 and moment coefficient corresponding to corresponding the first tapped hole, and K is limited by following formula:

Wherein, d ₂be the effective diameter of thread of the first screw 4, be the lead angle of the first screw 4, ρ _vbe the screw thread equivalent friction angle of the first screw 4, μ is the friction factor between head and the supporting surface contacting with it of the first screw 4, D _wand d ₀be respectively the head of the first screw 4 and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of the first screw 4.Thereby can guarantee to there is enough joggle numbers between the first tapped hole and corresponding the first screw 4, with the reliability of guaranteeing to be threaded.

In embodiment of the present utility model, from upper bearing (metal) side with from the first urgent screw 4 of lower bearing side, be all connected to difference the first tapped hole cylinder 1, be that at least one first sub-screw 4a and at least one second sub-screw 4b are connected to respectively difference the first tapped hole on cylinder 1, thereby can cause the first tapped hole quantity on cylinder 1 to increase, the reliability that now safe distance between the first tapped hole connects for the first screw 4 seems most important.Fig. 7 is minimum wall thickness (MINI W.) h plotted curve between the first tapped hole radial deformation-the first tapped hole.Visible along with the reducing of wall thickness h between two the first tapped holes, the impact between them increases gradually, and sharply increases after wall thickness h is less than 3mm, and the screw of different nominal diameters has all shown this rule.When screw pretightening force is identical with minimum wall thickness (MINI W.) h between two the first tapped holes, along with the increase of nominal diameter, between two the first tapped holes, impact slightly increases.The reliability excessive for fear of influencing each other between each first tapped hole, assurance is threaded, in preferred embodiment of the present utility model, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the first tapped holes of cylinder 1.That is to say each first tapped hole on cylinder 1 and the minimum wall thickness (MINI W.) h >=3mm between other first tapped holes on this cylinder 1.

In embodiments more of the present utility model, on cylinder 1, be also provided with the first screwing through hole (scheming not shown), single cylinder rotary compressor 100 also comprises the second screw (scheming not shown), and the second screw tightens together upper bearing (metal) 2, cylinder 1 and lower bearing 3 through the first screwing through hole on cylinder 1.That is to say, between cylinder 1, upper bearing (metal) 2 and lower bearing 3, except adopting the Placement that the first screw coordinates one by one with the first tapped hole, can also adopt the Placement coordinating of second screw and the first screwing through hole simultaneously.Wherein, the first screw can be that the tapped hole being fixedly attached on upper bearing (metal) 2 can be also the tapped hole being fixedly attached on lower bearing 3.

It should be noted that, the utility model is not limited to this, according to the utility model embodiment's single cylinder rotary compressor, as long as guaranteeing on following basis: have at least the first screw that connects upper bearing (metal) and cylinder to be connected to the first tapped hole on cylinder, and this first tapped hole is not connected with other any first screws, simultaneously, have at least the screw of a connection lower bearing and cylinder to be connected to the first tapped hole on cylinder, and this first tapped hole is not connected with other any first screws, the upper bearing (metal) of the utility model embodiment's single cylinder rotary compressor, between cylinder and lower bearing, can also adopt any Placement.

Below with reference to Fig. 8-Figure 11, describe according to three embodiments' of the utility model duplex-cylinder rotary compressor 200, wherein, the working principle of duplex-cylinder rotary compressor 200 etc. is those skilled in the art to be known, and is not just described in detail here.

Embodiment 1:

As shown in Figure 8 and Figure 9, in embodiment of the present utility model, duplex-cylinder rotary compressor 200 comprises: the first cylinder 5, the second cylinder 6, central diaphragm 7, upper bearing (metal) 2, lower bearing 3, a plurality of the 3rd screw 10 and a plurality of the 4th screw 11.Wherein, the first cylinder 5, the second cylinder 6, central diaphragm 7, upper bearing (metal) 2, lower bearing 3, a plurality of the 3rd screw 10 and a plurality of the 4th screw 11 construct the compression member portion of duplex-cylinder rotary compressor 200.

The first cylinder 5 is positioned at the top of the second cylinder 6, the first cylinder 5 is provided with a plurality of the second tapped holes (scheming not shown), the second cylinder 6 is provided with a plurality of the 3rd tapped holes (scheming not shown), and on the first cylinder 5 and the second cylinder 6, is respectively equipped with for assembling the vane slot 14 of slide plate and for assembling the suction port 13 of conical pipe 12.

Central diaphragm 7 is located between the first cylinder 5 and the second cylinder 6.Upper bearing (metal) 2 be located at the first cylinder 5 above, between upper bearing (metal) 2, the first cylinder 5 and central diaphragm 7, limit the active chamber of the first cylinder 5.Lower bearing 3 be located at the second cylinder 6 below, between central diaphragm 7, the second cylinder 6 and lower bearing 3, limit the active chamber of the second cylinder 6.

A plurality of the 3rd screws 10 respectively with a plurality of the second tapped holes corresponding matching one by one, a part in a plurality of the 3rd screws 10 coordinates with the part in a plurality of the second tapped holes through upper bearing (metal) 2, and the remaining part in a plurality of the 3rd screws 10 coordinates with the remaining part in a plurality of the second tapped holes through lower bearing 3, the second cylinder 6 and central diaphragm 7.That is to say, corresponding the 3rd screw 10 of each second tapped hole, the 3rd screw 10 that connects upper bearing (metal) 2 and the first cylinder 5 is connected to the second tapped hole on the first cylinder 5, and this second tapped hole is not connected with other any the 3rd screws 10.The 3rd screw 10 that connects lower bearing 3, the second cylinder 6, central diaphragm 7 and the first cylinder 5 is connected to the second tapped hole on the first cylinder 5, and this second tapped hole is not connected with other any the 3rd screws 10.

Particularly, a plurality of the 3rd screws 10 comprise at least one the 3rd sub-screw 10a and at least one the 4th sub-screw 10b, the 3rd sub-screw 10a is connected to part the second tapped hole on the first cylinder 5 upper bearing (metal) 2 is fixed on the first cylinder 5 through upper bearing (metal) 2, the 4th sub-screw 10b is through lower bearing 3, the second cylinder 6 and central diaphragm 7 are connected to remaining part the second tapped hole on the first cylinder 5 with by lower bearing 3, the second cylinder 6, central diaphragm 7 and the first cylinder 5 are fixed together, wherein, the second tapped hole that each the 3rd sub-screw 10a is corresponding does not coordinate with other any the 3rd screws 10, the second tapped hole that each the 4th sub-screw 10b is corresponding does not coordinate with other any the 3rd screws 10.

A plurality of the 4th screws 11 respectively with a plurality of the 3rd tapped holes corresponding matching one by one, a part in a plurality of the 4th screws 11 coordinates with the part in a plurality of the 3rd tapped holes through lower bearing 3, and the remaining part in a plurality of the 4th screws 11 coordinates with the remaining part in a plurality of the 3rd tapped holes through upper bearing (metal) 2, the first cylinder 5 and central diaphragm 7.That is to say, each the 3rd tapped hole coordinates with the 4th screw 11, the 4th screw 11 that connects lower bearing 3 and the second cylinder 6 is connected to part the 3rd tapped hole on the second cylinder 6, and the 3rd tapped hole is not connected with other any the 4th screws 11, simultaneously, the 4th screw 11 that connects upper bearing (metal) 2, the second cylinder 6, central diaphragm 7 and the first cylinder 5 is connected to remaining part the 3rd tapped hole on the second cylinder 6, and the 3rd tapped hole is not connected with other any the 4th screws 11.

Particularly, a plurality of the 4th screws 11 comprise at least one the 5th sub-screw 11a and at least one the 6th sub-screw 11b, at least one the 5th sub-screw 11a is connected with part the 3rd tapped hole on the second cylinder 6 through lower bearing 3, at least one the 6th sub-screw 11b is successively through upper bearing (metal) 2, the first cylinder 5 is connected with remaining part the 3rd tapped hole on the second cylinder 6 with central diaphragm 7, wherein, the 3rd tapped hole that each the 5th sub-screw 11a is corresponding does not coordinate with other any the 4th screws 11, the 3rd tapped hole that each the 6th sub-screw 11b is corresponding does not coordinate with other any the 4th screws 11.

Fig. 9 means the plan view that Fig. 8 compression member portion attachment screw distributes, what in figure, solid line represented is from the 3rd urgent screw 10 of upper bearing (metal) side, what dotted line represented is from the 3rd urgent screw 10 of lower bearing side, can meet the little requirement of cylinder height of duplex-cylinder rotary compressor 200.In the present embodiment, have the 3rd screw 10 of two connection upper bearing (metal)s 2 and the first cylinder 5 to be connected to the second tapped hole (having two the 3rd sub-screw 10a to be connected to the second tapped hole) on the first cylinder 5, and the second tapped hole is not connected with other any screws.Have the 3rd screw 10 of three connection lower bearings 3, the second cylinder 6, central diaphragm 7 and the first cylinder 5 to be connected to the second tapped hole (having three the 4th sub-screw 10b to be connected to the second tapped hole) on the first cylinder 5, and this second tapped hole is not connected with other any screws.Have the 4th screw 11 of two connection lower bearings 3 and the second cylinder 6 to be connected to the 3rd tapped hole (having two the 5th sub-screw 11a to be connected to the 3rd tapped hole) on the second cylinder 6, and the 3rd tapped hole is not connected with other any screws.Have the 4th screw 11 of three connection upper bearing (metal)s 2, the first cylinder 5, central diaphragm 7 and the second cylinder 6 to be connected to the 3rd tapped hole (having three the 6th sub-screw 11b to be connected to the 3rd tapped hole) on the second cylinder 6, and the 3rd tapped hole is not connected with other any screws.

Wherein, it should be noted that, according to the stressing conditions of the first cylinder 5 of the utility model embodiment's duplex-cylinder rotary compressor 200 and the second cylinder 6, with identical according to the stressing conditions principle of the cylinder 1 in the single cylinder rotary compressor 100 of the utility model above-described embodiment, be just not described in detail here.

According to the utility model embodiment's duplex-cylinder rotary compressor 200, can improve the resistivity that the first cylinder 5 and 6 pairs, the second cylinder are applied to the lateral force on the first cylinder 5 and the second cylinder 6 simultaneously, guarantee the reliability that compression member portion connects, be conducive to reduce the torsional deformation of the vane slot 14 on the first cylinder 5 and the second cylinder 6 simultaneously.

Wherein, it should be noted that, minimum wall thickness (MINI W.) design principle between minimum wall thickness (MINI W.) design principle between the design principle of the length of action between the design principle of the length of action between the 3rd screw 10 and the second tapped hole, the 4th screw 11 and the 3rd tapped hole, each second tapped hole of the first cylinder 5, each the 3rd tapped hole of the second cylinder 6 is similar with according in the single cylinder rotary compressor 100 of the utility model above-described embodiment all, just repeats no more here.

Therefore,, in embodiments more of the present utility model, the length of action L1 between each the 3rd screw 10 and corresponding the second tapped hole meets following formula:

$L1\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of the 3rd screw 10, and d is the screw thread nominal diameter of the 3rd screw 10, σ _sbe the yield strength of the 3rd screw 10, K is each the 3rd screw 10 and moment coefficient corresponding to corresponding the second tapped hole, and K is limited by following formula:

Wherein, d ₂be the effective diameter of thread of the 3rd screw 10, be the lead angle of the 3rd screw 10, ρ _vbe the screw thread equivalent friction angle of the 3rd screw 10, μ is the friction factor between head and the supporting surface contacting with it of the 3rd screw 10, D _wand d ₀be respectively the head of the 3rd screw 10 and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of the 3rd screw 10.Thereby guarantee to there is enough joggle numbers between the second tapped hole on the first cylinder 5 and corresponding the 3rd screw 10, and then guarantee the reliability that is threaded.

In preferred embodiment of the present utility model, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the second tapped holes of the first cylinder 5.That is to say each second tapped hole on the first cylinder 5 and the minimum wall thickness (MINI W.) h >=3mm between other second tapped holes on the first cylinder 5.Thereby by guaranteeing the wall thickness between every two the second tapped holes on the first cylinder 5, avoid influencing each other between each second tapped hole excessive, improve the reliability being threaded.

According to embodiments more of the present utility model, the length of action L2 between each the 4th screw 11 and corresponding the 3rd tapped hole meets following formula:

$L2\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of the 4th screw 11, and d is the screw thread nominal diameter of the 4th screw 11, σ _sbe the yield strength of the 4th screw 11, K is each the 4th screw 11 and moment coefficient corresponding to corresponding the 3rd tapped hole, and K is limited by following formula:

Wherein, d ₂be the effective diameter of thread of the 4th screw 11, be the lead angle of the 4th screw 11, ρ _vbe the screw thread equivalent friction angle of the 4th screw 11, μ is the friction factor between head and the supporting surface contacting with it of the 4th screw 11, D _wand d ₀be respectively the head of the 4th screw 11 and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of the 4th screw 11.Thereby guarantee to there is enough joggle numbers between the 3rd tapped hole on the second cylinder 6 and corresponding the 4th screw 11, and then guarantee the reliability that is threaded.

In preferred embodiment of the present utility model, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the 3rd tapped holes of the second cylinder 6.That is to say each the 3rd tapped hole on the second cylinder 6 and the minimum wall thickness (MINI W.) h >=3mm between other the 3rd tapped holes on the second cylinder 6.Thereby by guaranteeing the wall thickness between every two the 3rd tapped holes on the second cylinder 6, avoid influencing each other between each the 3rd tapped hole excessive, improve the reliability being threaded.

In embodiments more of the present utility model, on the first cylinder 5, be also provided with the second screwing through hole (scheming not shown), duplex-cylinder rotary compressor 200 also comprises the 5th screw (scheming not shown), and the 5th screw tightens together upper bearing (metal) 2, the first cylinder 5 and central diaphragm 7 through the second screwing through hole on the first cylinder 5.

On the second cylinder 6, be also provided with the 3rd screwing through hole (scheming not shown), duplex-cylinder rotary compressor 200 also comprises the 6th screw (scheming not shown), and the 6th screw tightens together lower bearing 3, the second cylinder 6 and central diaphragm 7 through the 3rd screwing through hole on the second cylinder 6.

That is to say, between upper bearing (metal) 2, the first cylinder 5, central diaphragm 7, the second cylinder 6 and lower bearing 3 except adopting the Placement that the second tapped hole coordinates one by one with the 3rd screw 10 and the 3rd tapped hole coordinates one by one with the 4th screw 11, can also adopt the Placement of the second screwing through hole and the 5th screw fit simultaneously, certainly can also adopt the Placement of the 3rd screwing through hole and the 6th screw fit simultaneously.

It should be noted that, the utility model is not limited to this, according to the utility model embodiment's duplex-cylinder rotary compressor, as long as guaranteeing on following basis: have at least the 3rd screw 10 that connects upper bearing (metal) 2 and the first cylinder 5 to be connected to the second tapped hole on the first cylinder 5, and this second tapped hole is not connected with other any the 3rd screws 10; Have at least the 3rd screw 10 of a connection lower bearing 3, the second cylinder 6, central diaphragm 7 and the first cylinder 5 to be connected to the second tapped hole on the first cylinder 5, and this second tapped hole is not connected with other any the 3rd screws 10; Have at least the 4th screw 11 of a connection lower bearing 3 and the second cylinder 6 to be connected to the 3rd tapped hole on the second cylinder 6, and the 3rd tapped hole is not connected with other any the 4th screws 11; Have at least the 4th screw 11 of a connection upper bearing (metal) 2, the first cylinder 5, central diaphragm 7 and the second cylinder 6 to be connected to the 3rd tapped hole on the second cylinder 6, and the 3rd tapped hole is not connected with other any the 4th screws 11.Between the upper bearing (metal) 2 of the utility model embodiment's duplex-cylinder rotary compressor, the first cylinder 5, central diaphragm 7, the second cylinder 6 and lower bearing 3, can also adopt any Placement.

In some cases, in duplex-cylinder rotary compressor 200, a cylinder connection reliability requires higher than another cylinder, such as the design that has a cylinder height apparently higher than another cylinder in variable volume compressor, this by cause cylinder that cylinder height is higher under identical working condition, be subject to gas side to power far above another cylinder, this just requires to lay particular stress on to some extent in design, and the embodiment 2 and the embodiment 3 that at the utility model, the following describes are applicable to above-mentioned application.

Embodiment 2:

In this embodiment, suppose that the first cylinder 5 connection reliability have relatively high expectations, requirement is lower for the second cylinder 6, as shown in figure 10, duplex-cylinder rotary compressor 200 according to the utility model embodiment, comprising: the first cylinder 5, the second cylinder 6, central diaphragm 7, upper bearing (metal) 2, lower bearing 3 and a plurality of the 3rd screw 10.Wherein, the first cylinder 5, the second cylinder 6, central diaphragm 7, upper bearing (metal) 2, lower bearing 3 and a plurality of the 3rd screw 10 construct the compression member portion of duplex-cylinder rotary compressor 200.

The first cylinder 5 is positioned at the top of the second cylinder 6, and the first cylinder 5 is provided with a plurality of the second tapped holes, and on the first cylinder 5 and the second cylinder 6, is respectively equipped with for assembling the vane slot 14 of slide plate and for assembling the suction port 13 of conical pipe 12.

Central diaphragm 7 is located between the first cylinder 5 and the second cylinder 6.Upper bearing (metal) 2 be located at the first cylinder 5 above, between upper bearing (metal) 2, the first cylinder 5 and central diaphragm 7, limit the active chamber of the first cylinder 5.Lower bearing 3 be located at the second cylinder 6 below, between central diaphragm 7, the second cylinder 6 and lower bearing 3, limit the active chamber of the second cylinder 6.

A plurality of the 3rd screws 10 respectively with a plurality of the second tapped holes corresponding matching one by one, a part in a plurality of the 3rd screws 10 coordinates with the part in a plurality of the second tapped holes through upper bearing (metal) 2, and the remaining part in a plurality of the 3rd screws 10 coordinates with the remaining part in a plurality of the second tapped holes through lower bearing 3, the second cylinder 6 and central diaphragm 7.That is to say, corresponding the 3rd screw 10 of each second tapped hole, the 3rd screw 10 that connects upper bearing (metal) 2 and the first cylinder 5 is connected to the second tapped hole on the first cylinder 5, and this second tapped hole is not connected with other any the 3rd screws 10.The 3rd screw 10 that connects lower bearing 3, the second cylinder 6, central diaphragm 7 and the first cylinder 5 is connected to the second tapped hole on the first cylinder 5, and this second tapped hole is not connected with other any the 3rd screws 10.

Particularly, a plurality of the 3rd screws 10 comprise at least one the 3rd sub-screw 10a and at least one the 4th sub-screw 10b, the 3rd sub-screw 10a is connected to part the second tapped hole on the first cylinder 5 upper bearing (metal) 2 is fixed on the first cylinder 5 through upper bearing (metal) 2, the 4th sub-screw 10b is through lower bearing 3, the second cylinder 6 and central diaphragm 7 are connected to remaining part the second tapped hole on the first cylinder 5 with by lower bearing 3, the second cylinder 6, central diaphragm 7 and the first cylinder 5 are fixed together, wherein, the second tapped hole that each the 3rd sub-screw 10a is corresponding does not coordinate with other any the 3rd screws 10, the second tapped hole that each the 4th sub-screw 10b is corresponding does not coordinate with other any the 3rd screws 10.As shown in figure 11, in figure, solid line represents from the urgent screw of upper bearing (metal) 2 (i.e. the 3rd sub-screw 10a), what in figure, dotted line represented is from the urgent screw of lower bearing 3 (i.e. the 4th sub-screw 10b), from the urgent screw of upper bearing (metal) 2 with from the urgent screw of lower bearing 3, be all connected to difference the second tapped hole the first cylinder 5, thereby can meet the little requirement of cylinder height of duplex-cylinder rotary compressor 200.

In the example depicted in fig. 11, the remaining part of a part for a plurality of the 3rd screws 10 and a plurality of the 3rd screws 10 is interspersed, and that is to say, at least one the 3rd sub-screw 10a and at least one the 4th sub-screw 10b are interspersed.

Wherein, it should be noted that, according to the stressing conditions of the first cylinder 5 of the utility model embodiment's duplex-cylinder rotary compressor 200, with identical according to the stressing conditions principle of the cylinder 1 of the single cylinder rotary compressor 100 of the utility model above-described embodiment, be just not described in detail here.

According to the utility model embodiment's duplex-cylinder rotary compressor 200, by the part in a plurality of the 3rd screws 10 is coordinated with the part in a plurality of the second tapped holes through upper bearing (metal) 2, remaining part in a plurality of the 3rd screws 10 is through lower bearing 3, the second cylinder 6 and central diaphragm 7 coordinate with the remaining part in a plurality of the second tapped holes, thereby can improve the resistivity that 5 pairs, the first cylinder acts on the lateral force on the first cylinder 5, guarantee the connection reliability between the first cylinder 5 and upper bearing (metal) 2, and guaranteed the first cylinder 5, central diaphragm 7, connection reliability between the second cylinder 6 and lower bearing 3, be conducive to reduce the torsional deformation of the vane slot 14 of the first cylinder 5 simultaneously.

In this embodiment, the second cylinder 6 can adopt cylinder via design completely, for the consideration that reduces assembly technology difficulty, two Screws be can design in addition and lower bearing 3 and the second cylinder 6 connected, during assembling, first distinguish fastening lower bearing 3 and the second cylinder 6, upper bearing (metal) 2 and the first cylinder 5, then tighten together with miscellaneous parts such as central diaphragms 7.

Wherein, it should be noted that, minimum wall thickness (MINI W.) design principle between each second tapped hole of the design principle of the length of action between the 3rd screw 10 and the second tapped hole, the first cylinder 5 is similar with according in the single cylinder rotary compressor 100 of the utility model above-described embodiment all, just repeats no more here.

Therefore,, according to embodiments more of the present utility model, the length of action L1 between each the 3rd screw 10 and corresponding the second tapped hole meets following formula:

$L1\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of the 3rd screw 10, and d is the screw thread nominal diameter of the 3rd screw 10, σ _sbe the yield strength of the 3rd screw 10, K is each the 3rd screw 10 and moment coefficient corresponding to corresponding the second tapped hole, and K is limited by following formula:

Wherein, d ₂be the effective diameter of thread of the 3rd screw 10, be the lead angle of the 3rd screw 10, ρ _vbe the screw thread equivalent friction angle of the 3rd screw 10, μ is the friction factor between head and the supporting surface contacting with it of the 3rd screw 10, D _wand d ₀be respectively the head of the 3rd screw 10 and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of the 3rd screw 10.Thereby guarantee to there is enough joggle numbers between the second tapped hole on the first cylinder 5 and corresponding the 3rd screw 10, and then guarantee the reliability that is threaded.

In preferred embodiment of the present utility model, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the second tapped holes of the first cylinder 5.That is to say each second tapped hole on the first cylinder 5 and the minimum wall thickness (MINI W.) h >=3mm between other second tapped holes on the first cylinder 5.Thereby by guaranteeing the wall thickness between every two the second tapped holes on the first cylinder 5, avoid influencing each other between each second tapped hole excessive, improve the reliability being threaded.

In embodiments more of the present utility model, on the first cylinder 5, be also provided with the second screwing through hole (scheming not shown), duplex-cylinder rotary compressor 200 also comprises the 5th screw (scheming not shown), and the 5th screw tightens together upper bearing (metal) 2, the first cylinder 5 and central diaphragm 7 through the second screwing through hole on the first cylinder 5.

That is to say, between upper bearing (metal) 2, the first cylinder 5, central diaphragm 7, the second cylinder 6 and lower bearing 3, except adopting the Placement that the second tapped hole coordinates one by one with the 3rd screw 10, can also adopt the Placement of the second screwing through hole and the 5th screw fit simultaneously.

It should be noted that, the utility model is not limited to this, according to the utility model embodiment's duplex-cylinder rotary compressor, as long as guaranteeing on following basis: have at least the 3rd screw 10 that connects upper bearing (metal) 2 and the first cylinder 5 to be connected to the second tapped hole on the first cylinder 5, and this second tapped hole is not connected with other any the 3rd screws 10; Have at least the 3rd screw 10 of a connection lower bearing 3, the second cylinder 6, central diaphragm 7 and the first cylinder 5 to be connected to the second tapped hole on the first cylinder 5, and this second tapped hole is not connected with other any the 3rd screws 10.Between the upper bearing (metal) 2 of the utility model embodiment's duplex-cylinder rotary compressor, the first cylinder 5, central diaphragm 7, the second cylinder 6 and lower bearing 3, can also adopt any Placement.

Embodiment 3:

In this embodiment, the second cylinder 6 connection reliability are had relatively high expectations, and require lower to the connection reliability of the first cylinder 5.Duplex-cylinder rotary compressor 200 according to the utility model embodiment, comprising: the first cylinder 5, the second cylinder 6, central diaphragm 7, upper bearing (metal) 2, lower bearing 3 and a plurality of the 4th screw 11.Wherein, the first cylinder 5, the second cylinder 6, central diaphragm 7, upper bearing (metal) 2, lower bearing 3 and a plurality of the 4th screw 11 construct the compression member portion of duplex-cylinder rotary compressor 200.

The first cylinder 5 is positioned at the top of the second cylinder 6, and the second cylinder 6 is provided with a plurality of the 3rd tapped holes, and on the first cylinder 5 and the second cylinder 6, is respectively equipped with for assembling the vane slot 14 of slide plate and for assembling the suction port 13 of conical pipe 12.

Central diaphragm 7 is located between the first cylinder 5 and the second cylinder 6.Upper bearing (metal) 2 be located at the first cylinder 5 above, between upper bearing (metal) 2, the first cylinder 5 and central diaphragm 7, limit the active chamber of the first cylinder 5.Lower bearing 3 be located at the second cylinder 6 below, between central diaphragm 7, the second cylinder 6 and lower bearing 3, limit the active chamber of the second cylinder 6.

A plurality of the 4th screws 11 respectively with a plurality of the 3rd tapped holes corresponding matching one by one, a part in a plurality of the 4th screws 11 coordinates with the part in a plurality of the 3rd tapped holes through lower bearing 3, and the remaining part in a plurality of the 4th screws 11 coordinates with the remaining part in a plurality of the 3rd tapped holes through upper bearing (metal) 2, the first cylinder 5 and central diaphragm 7.That is to say, each the 3rd tapped hole coordinates with the 4th screw 11, the 4th screw 11 that connects lower bearing 3 and the second cylinder 6 is connected to part the 3rd tapped hole on the second cylinder 6, and the 3rd tapped hole is not connected with other any the 4th screws 11, simultaneously, the 4th screw 11 that connects upper bearing (metal) 2, the second cylinder 6, central diaphragm 7 and the first cylinder 5 is connected to remaining part the 3rd tapped hole on the second cylinder 6, and the 3rd tapped hole is not connected with other any the 4th screws 11.

Particularly, a plurality of the 4th screws 11 comprise at least one the 5th sub-screw 11a and at least one the 6th sub-screw 11b, at least one the 5th sub-screw 11a is connected with part the 3rd tapped hole on the second cylinder 6 through lower bearing 3, at least one the 6th sub-screw 11b is successively through upper bearing (metal) 2, the first cylinder 5 is connected with remaining part the 3rd tapped hole on the second cylinder 6 with central diaphragm 7, wherein, the 3rd tapped hole that each the 5th sub-screw 11a is corresponding does not coordinate with other any the 4th screws 11, the 3rd tapped hole that each the 6th sub-screw 11b is corresponding does not coordinate with other any the 4th screws 11.As shown in Figure 9, in figure, solid line represents from the urgent screw of upper bearing (metal) 2 (i.e. the 5th sub-screw 11a), what in figure, dotted line represented is from the urgent screw of lower bearing 3 (i.e. the 6th sub-screw 11b), from the urgent screw of upper bearing (metal) 2 with from the urgent screw of lower bearing 3, be all connected to difference the 3rd tapped hole the second cylinder 6, thereby can meet the little requirement of cylinder height of duplex-cylinder rotary compressor 200.

The remaining part of a part for a plurality of the 4th screws 11 and a plurality of the 4th screws 11 is interspersed.That is to say, at least one the 5th sub-screw 11a and at least one the 6th sub-screw 11b are interspersed.

Thereby, according to the utility model embodiment's duplex-cylinder rotary compressor 200, by the part in a plurality of the 4th screws 11 is coordinated with the part in a plurality of the 3rd tapped holes through lower bearing 3, remaining part in a plurality of the 4th screws 11 is through upper bearing (metal) 2, the first cylinder 5 and central diaphragm 7 coordinate with the remaining part in a plurality of the 3rd tapped holes, thereby can improve the resistivity that 6 pairs, the second cylinder acts on the lateral force on the second cylinder 6, guarantee the connection reliability between the second cylinder 6 and lower bearing 3, and guaranteed upper bearing (metal) 2, the first cylinder 5, connection reliability between central diaphragm 7 and the second cylinder 6, be conducive to reduce the torsional deformation of the vane slot 14 of the second cylinder 6 simultaneously.

Wherein, it should be noted that, minimum wall thickness (MINI W.) design principle between each the 3rd tapped hole of the design principle of the length of action between the 4th screw 11 and the 3rd tapped hole, the second cylinder 6 is similar with according in the single cylinder rotary compressor 100 of the utility model above-described embodiment all, just repeats no more here.

Therefore,, according to embodiments more of the present utility model, the length of action L2 between each the 4th screw 11 and corresponding the 3rd tapped hole meets following formula:

$L2\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of the 4th screw 11, and d is the screw thread nominal diameter of the 4th screw 11, σ _sbe the yield strength of the 4th screw 11, K is each the 4th screw 11 and moment coefficient corresponding to corresponding the 3rd tapped hole, and K is limited by following formula:

Wherein, d ₂be the effective diameter of thread of the 4th screw 11, be the lead angle of the 4th screw 11, ρ _vbe the screw thread equivalent friction angle of the 4th screw 11, μ is the friction factor between head and the supporting surface contacting with it of the 4th screw 11, D _wand d ₀be respectively the head of the 4th screw 11 and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of the 4th screw 11.Thereby guarantee to there is enough joggle numbers between the 3rd tapped hole on the second cylinder 6 and corresponding the 4th screw 11, and then guarantee the reliability that is threaded.

In preferred embodiment of the present utility model, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the 3rd tapped holes of the second cylinder 6.That is to say each the 3rd tapped hole on the second cylinder 6 and the minimum wall thickness (MINI W.) h >=3mm between other the 3rd tapped holes on the second cylinder 6.Thereby by guaranteeing the wall thickness between every two the 3rd tapped holes on the second cylinder 6, avoid influencing each other between each the 3rd tapped hole excessive, improve the reliability being threaded.

In embodiments more of the present utility model, on the second cylinder 6, be also provided with the 3rd screwing through hole (scheming not shown), duplex-cylinder rotary compressor 200 also comprises the 6th screw (scheming not shown), and the 6th screw tightens together lower bearing 3, the second cylinder 6 and central diaphragm 7 through the 3rd screwing through hole on the second cylinder 6.

That is to say, between upper bearing (metal) 2, the first cylinder 5, central diaphragm 7, the second cylinder 6 and lower bearing 3, except adopting the Placement that the 3rd tapped hole coordinates one by one with the 4th screw 11, can also adopt the Placement of the 3rd screwing through hole and the 6th screw fit simultaneously.

It should be noted that, the utility model is not limited to this, according to the utility model embodiment's duplex-cylinder rotary compressor, as long as guaranteeing on following basis: have at least the 4th screw 11 of a connection lower bearing 3 and the second cylinder 6 to be connected to the 3rd tapped hole on the second cylinder 6, and the 3rd tapped hole is not connected with other any the 4th screws 11; Have at least the 4th screw 11 of a connection upper bearing (metal) 2, the first cylinder 5, central diaphragm 7 and the second cylinder 6 to be connected to the 3rd tapped hole on the second cylinder 6, and the 3rd tapped hole is not connected with other any the 4th screws 11.Between the upper bearing (metal) 2 of the utility model embodiment's duplex-cylinder rotary compressor, the first cylinder 5, central diaphragm 7, the second cylinder 6 and lower bearing 3, can also adopt any Placement.

Wherein, it should be noted that, according to other configuration examples of the utility model embodiment's single cylinder rotary compressor 100 and duplex-cylinder rotary compressor 200 as structures such as piston, slide plate, liquid containers, be all prior art, and known by those skilled in the art, be that these parts can design according to existing mode completely, just describe in detail no longer one by one here.

In description of the present utility model, it will be appreciated that, term " " center ", " longitudinally ", " laterally ", " length ", " width ", " thickness ", " on ", D score, " front ", " afterwards ", " left side ", " right side ", " vertically ", " level ", " top ", " end " " interior ", " outward ", " clockwise ", " counterclockwise ", " axially ", " radially ", orientation or the position relationship of indications such as " circumferentially " are based on orientation shown in the drawings or position relationship, only the utility model and simplified characterization for convenience of description, rather than device or the element of indication or hint indication must have specific orientation, with specific orientation structure and operation, therefore can not be interpreted as restriction of the present utility model.

In addition, term " first ", " second " be only for describing object, and can not be interpreted as indication or hint relative importance or the implicit quantity that indicates indicated technical characteristics.Thus, one or more these features can be expressed or impliedly be comprised to the feature that is limited with " first ", " second ".In description of the present utility model, the implication of " a plurality of " is two or more, unless otherwise expressly limited specifically.

In the utility model, unless otherwise clearly defined and limited, the terms such as term " installation ", " being connected ", " connection ", " fixing " should be interpreted broadly, and for example, can be to be fixedly connected with, and can be also to removably connect, or be integral; Can be mechanical connection, can be to be also electrically connected to; Can be to be directly connected, also can indirectly be connected by intermediary, can be the connection of two element internals or the interaction relationship of two elements.For the ordinary skill in the art, can understand as the case may be the concrete meaning of above-mentioned term in the utility model.

In the utility model, unless otherwise clearly defined and limited, First Characteristic Second Characteristic " on " or D score can be that the first and second features directly contact, or the first and second features are by intermediary mediate contact.And, First Characteristic Second Characteristic " on ", " top " and " above " but First Characteristic directly over Second Characteristic or oblique upper, or only represent that First Characteristic level height is higher than Second Characteristic.First Characteristic Second Characteristic " under ", " below " and " below " can be First Characteristic under Second Characteristic or tiltedly, or only represent that First Characteristic level height is less than Second Characteristic.

In the description of this specification, the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means to be contained at least one embodiment of the present utility model or example in conjunction with specific features, structure, material or the feature of this embodiment or example description.In this manual, to the schematic statement of above-mentioned term not must for be identical embodiment or example.And, the specific features of description, structure, material or feature can one or more embodiments in office or example in suitable mode combination.In addition,, not conflicting in the situation that, those skilled in the art can carry out combination and combination by the feature of the different embodiments that describe in this specification or example and different embodiment or example.

Although illustrated and described embodiment of the present utility model above, be understandable that, above-described embodiment is exemplary, can not be interpreted as restriction of the present utility model, those of ordinary skill in the art can change above-described embodiment in scope of the present utility model, modification, replacement and modification.

Claims (18)

1. a single cylinder rotary compressor, is characterized in that, comprising:

Cylinder, described cylinder is provided with a plurality of the first tapped holes;

Upper bearing (metal), described upper bearing (metal) be located at described cylinder above;

Lower bearing, described lower bearing be located at described cylinder below;

A plurality of the first screws, described a plurality of the first screw respectively with described a plurality of the first tapped holes corresponding matching one by one, the part in described a plurality of the first screws coordinates that with a part for described a plurality of the first tapped holes described upper bearing (metal) is fixed on described cylinder through described upper bearing (metal); Remaining part in described a plurality of the first screw coordinates that with the remaining part in described a plurality of the first tapped holes described lower bearing is fixed on described cylinder through described lower bearing.

2. single cylinder rotary compressor according to claim 1, it is characterized in that, on described cylinder, be also provided with the first screwing through hole, described single cylinder rotary compressor also comprises the second screw, and described the second screw tightens together described upper bearing (metal), described cylinder and described lower bearing through the first screwing through hole on described cylinder.

3. single cylinder rotary compressor according to claim 1, is characterized in that, the length of action L described in each between the first screw and corresponding described the first tapped hole meets following formula:

$L\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of described the first screw, and d is the screw thread nominal diameter of described the first screw, σ _sfor the yield strength of described the first screw, K is the first screw and corresponding moment coefficient corresponding to described the first tapped hole described in each, and K is limited by following formula:

Wherein, d ₂for the effective diameter of thread of described the first screw, for the lead angle of described the first screw, ρ _vfor the screw thread equivalent friction angle of described the first screw, μ is the friction factor between head and the supporting surface contacting with it of described the first screw, D _wand d ₀be respectively the head of described the first screw and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of described the first screw.

4. single cylinder rotary compressor according to claim 1, is characterized in that, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the first tapped holes of described cylinder.

5. single cylinder rotary compressor according to claim 1, is characterized in that, a described part for described a plurality of the first screws and the described remaining part of described a plurality of the first screws are interspersed.

6. a duplex-cylinder rotary compressor, is characterized in that, comprising:

The first cylinder and the second cylinder, described the first cylinder is positioned at the top of described the second cylinder, and described the first cylinder is provided with a plurality of the second tapped holes;

Central diaphragm, described central diaphragm is located between described the first cylinder and described the second cylinder;

Upper bearing (metal), described upper bearing (metal) be located at described the first cylinder above;

Lower bearing, described lower bearing be located at described the second cylinder below;

A plurality of the 3rd screws, described a plurality of the 3rd screw respectively with described a plurality of the second tapped holes corresponding matching one by one, a part in described a plurality of the 3rd screw coordinates with the part in described a plurality of the second tapped holes through described upper bearing (metal), and the remaining part in described a plurality of the 3rd screws coordinates with the remaining part in described a plurality of the second tapped holes through described lower bearing, the second cylinder and central diaphragm.

7. duplex-cylinder rotary compressor according to claim 6, is characterized in that, the length of action L1 described in each between the 3rd screw and corresponding described the second tapped hole meets following formula:

$L1\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of described the 3rd screw, and d is the screw thread nominal diameter of described the 3rd screw, σ _sfor the yield strength of described the 3rd screw, K is the 3rd screw and corresponding moment coefficient corresponding to described the second tapped hole described in each, and K is limited by following formula:

Wherein, d ₂for the effective diameter of thread of described the 3rd screw, for the lead angle of described the 3rd screw, ρ _vfor the screw thread equivalent friction angle of described the 3rd screw, μ is the friction factor between head and the supporting surface contacting with it of described the 3rd screw, D _wand d ₀be respectively the head of described the 3rd screw and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of described the 3rd screw.

8. duplex-cylinder rotary compressor according to claim 6, is characterized in that, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the second tapped holes of described the first cylinder.

9. duplex-cylinder rotary compressor according to claim 6, is characterized in that, the described remaining part of a described part for described a plurality of the 3rd screws and described a plurality of the 3rd screws is interspersed.

10. duplex-cylinder rotary compressor according to claim 6, it is characterized in that, described the second cylinder is provided with a plurality of the 3rd tapped holes, described duplex-cylinder rotary compressor also comprises a plurality of the 4th screws, described a plurality of the 4th screw respectively with described a plurality of the 3rd tapped holes corresponding matching one by one, a part in described a plurality of the 4th screw coordinates with the part in described a plurality of the 3rd tapped holes through described lower bearing, remaining part in described a plurality of the 4th screw is through described upper bearing (metal), described the first cylinder and described central diaphragm coordinate with the remaining part in described a plurality of the 3rd tapped holes.

11. according to the duplex-cylinder rotary compressor described in claim 6 or 10, it is characterized in that, on described the first cylinder, be also provided with the second screwing through hole, described duplex-cylinder rotary compressor also comprises the 5th screw, and described the 5th screw tightens together described upper bearing (metal), described the first cylinder and described central diaphragm through the second screwing through hole on described the first cylinder.

12. duplex-cylinder rotary compressors according to claim 10, is characterized in that, the length of action L2 described in each between the 4th screw and corresponding described the 3rd tapped hole meets following formula:

$L2\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of described the 4th screw, and d is the screw thread nominal diameter of described the 4th screw, σ _sfor the yield strength of described the 4th screw, K is the 4th screw and corresponding moment coefficient corresponding to described the 3rd tapped hole described in each, and K is limited by following formula:

Wherein, d ₂for the effective diameter of thread of described the 4th screw, for the lead angle of described the 4th screw, ρ _vfor the screw thread equivalent friction angle of described the 4th screw, μ is the friction factor between head and the supporting surface contacting with it of described the 4th screw, D _wand d ₀be respectively the head of described the 4th screw and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of described the 4th screw.

13. duplex-cylinder rotary compressors according to claim 10, is characterized in that, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the 3rd tapped holes of described the second cylinder.

14. duplex-cylinder rotary compressors according to claim 10, it is characterized in that, on described the second cylinder, be also provided with the 3rd screwing through hole, described duplex-cylinder rotary compressor also comprises the 6th screw, and described the 6th screw tightens together described lower bearing, described the second cylinder and described central diaphragm through the 3rd screwing through hole on described the second cylinder.

15. 1 kinds of duplex-cylinder rotary compressors, is characterized in that, comprising:

The first cylinder and the second cylinder, described the first cylinder is positioned at the top of described the second cylinder, and described the second cylinder is provided with a plurality of the 3rd tapped holes;

Central diaphragm, described central diaphragm is located between described the first cylinder and described the second cylinder;

Upper bearing (metal), described upper bearing (metal) be located at described the first cylinder above;

Lower bearing, described lower bearing be located at described the second cylinder below;

A plurality of the 4th screws, a plurality of described the 4th screws respectively with described a plurality of the 3rd tapped holes corresponding matching one by one, a part in described a plurality of the 4th screw coordinates with the part in described a plurality of the 3rd tapped holes through described lower bearing, and the remaining part in described a plurality of the 4th screws coordinates with the remaining part in described a plurality of the 3rd tapped holes through described upper bearing (metal), described the first cylinder and described central diaphragm.

16. duplex-cylinder rotary compressors according to claim 15, is characterized in that, the length of action L2 described in each between the 4th screw and corresponding described the 3rd tapped hole meets following formula:

$L2\≥\frac{8T}{{\mathrm{\πd}}^2{\mathrm{K\σ}}_s}$

Wherein, T is the urgent moment of described the 4th screw, and d is the screw thread nominal diameter of described the 4th screw, σ _sfor the yield strength of described the 4th screw, K is the 4th screw and corresponding moment coefficient corresponding to described the 3rd tapped hole described in each, and K is limited by following formula:

Wherein, d ₂for the effective diameter of thread of described the 4th screw, for the lead angle of described the 4th screw, ρ _vfor the screw thread equivalent friction angle of described the 4th screw, μ is the friction factor between head and the supporting surface contacting with it of described the 4th screw, D _wand d ₀be respectively the head of described the 4th screw and external diameter and the internal diameter of the circular contact area of the supporting surface formation contacting with it, d is the screw thread nominal diameter of described the 4th screw.

17. duplex-cylinder rotary compressors according to claim 15, is characterized in that, the minimum wall thickness (MINI W.) h >=3mm of the part between every adjacent two the 3rd tapped holes of described the second cylinder.

18. duplex-cylinder rotary compressors according to claim 15, it is characterized in that, on described the second cylinder, be also provided with the 3rd screwing through hole, described duplex-cylinder rotary compressor also comprises the 6th screw, and described the 6th screw tightens together described lower bearing, described the second cylinder and described central diaphragm through the 3rd screwing through hole on described the second cylinder.