Reduce the refrigeration compressor piston of clearance volume
Technical field
The utility model relates to refrigeration compressor, belongs to small-sized connecting rod piston formula refrigeration compressor piston structure especially, can reduce the clearance volume that forms between piston end surface and the valve seat.
Technical background
Piston is housed in the compressor cylinder, and cylinder head is equipped with the air valve device (see figure 1).The valve seat both sides are respectively suction valve chip and discharge valve apparatus, and suction valve chip is near cylinder head.When the suction and discharge valve block is not worked at compressor, be close to the closure gasket groove of the orifice edge of the suction pore on the valve seat respectively.When compressor operating, suction and discharge air-flow antikinesis carries out air-breathing and exhaust.Suction valve chip is generally leaf valve, and the suction valve chip appearance profile is less than the piston tip plane.
When piston turned to the outer dead point operation by inner dead point, the gas in the cylinder was compressed, and the gas pressure increase makes suction valve chip close in the cylinder.When inner cylinder pressure constantly increases, when making the pressure reduction of exhaust valve plate both sides greater than the spring force of valve block self, exhaust valve plate is opened, the beginning exhaust process.Exhaust process finishes when piston runs to outer dead point.Exhaust valve plate is in closed condition.
For fear of the exhaust surface of running into suction valve chip, piston tip surface at the end, this moment is usually essential between piston tip surface and suction valve chip to keep certain clearance T, and this moment the piston end surface plane with the close surface of piston one side of valve seat between the gap length that forms be that T adds suction valve chip thickness.So at the end still remain in this part gap at compressor air-discharging with regard to some gas, simultaneously also residual a part of gas in the exhaust port on the valve seat.There is the space of residual gas to be called clearance volume.The volume that gap and exhaust port form has occupied the overwhelming majority of clearance volume.
When piston turned to the motion of inner dead point direction by outer dead point, suction valve chip expanded rapidly near the residual gas of cylinder side, and the gas of expansion has occupied a part of volume in the cylinder, had reduced effective aspirated volume in the cylinder.
At present, the piston head end face of most of compressor manufacturer is an even curface, and the problem of this piston-shaped existence is to have reduced effective aspirated volume.Influenced the compressor overall efficiency.Therefore how to reduce clearance volume, improve the volume and the overall efficiency of compressor, become the problem of relevant scientific research personnel's development and exploitation.
Summary of the invention
The technical problems to be solved in the utility model provides the refrigeration compressor piston that reduces clearance volume, and it can reduce the clearance volume that exhaust port brings, the clearance volume that bring in the gap that can reduce to form between piston tip plane and suction valve chip and valve base surface.Improve the volume and the overall efficiency of compressor.
For solving the problems of the technologies described above, the refrigeration compressor piston that reduces clearance volume of the present utility model, comprise piston body, its structure outline is that the plane, top of piston body is provided with a cylindrical small boss and one and is the uvula connected in star, this cylindrical small boss embeds mutually with the valve seat exhaust port, the suction valve chip of respective shapes fit mutually on this uvula connected in star and the air valve device.When the position of described cylindrical small boss guaranteed that piston runs to outer dead point, small boss was just in the inserted valve seat exhaust port, its volume size, the clearance volume that reduces exactly.When described uvula connected in star guaranteed the piston arrives outer dead point, the suction valve chip unrestricted motion was partially submerged in the uvula connected in star, and the thickness that the clearance volume of minimizing is equivalent to suction valve chip multiply by piston end surface removes area beyond " uvula " connected in star.
The diameter of described cylindrical small boss and highly all be slightly less than exhaust port on the valve seat.
Described cylindrical small boss root is connected with piston end surface interplanar arc transition.
The described uvula connected in star degree of depth is consistent with the material thickness of suction valve chip.
The utility model is owing to improved the design of piston end surface shape, compared with prior art, its useful technique effect is: reduced the clearance volume that forms between piston end surface and the valve seat, improved the volumetric efficiency of compressor, thereby improved the overall efficiency of compressor.
Description of drawings
Below with reference to drawings and Examples the utility model is further described.
Fig. 1 is prior art piston end surface structure and fundamental diagram.
Fig. 2 is a structural representation of the present utility model.
Fig. 3 is the utility model pistons work schematic diagram.
Among the figure: the 1st, cylinder; The 2nd, piston body; The 3rd, suction valve chip; The 4th, valve seat; The 5th, the cylindrical body small boss; The 6th, the uvula connected in star; The 7th, exhaust port.
Embodiment
As shown in Figures 2 and 3, on these embodiment's piston body 2 top ends a cylindrical body small boss 5 is arranged, the diameter of small boss 5 and highly be slightly less than exhaust port 7 on the air valve valve seat 4, small boss 5 roots are connected with piston body 2 top end arc transition.Piston 2 top ends have the groove 6 that is the uvula capitiform, and the degree of depth of groove 6 is consistent with suction valve chip 3 material thicknesses.Piston body 2 radial direction have piston pin hole, leave the space that connecting rod small end partly connects in the middle of the piston body.
During work, piston 2 is reciprocating in the cylinder 1 of compressor, and when piston 2 ran to outer dead point, the exhaust process of compressor finished.At this moment piston body 2 top plan (except that groove) and valve seat 4 have formed certain clearance T by between cylinder 1 side surface, and the suction valve chip 3 on the valve seat 4 just in time embeds and is uvula connected in star 6, and the gap that keeps between suction valve chip 3 surfaces and groove 6 bottoms also is T; The clearance volume size integral body of being brought by the gap is: piston body 2 diameters multiply by gap T.And piston body 2 top end faces are not when being with groove 6, the gap that forms between piston 2 surfaces and the suction valve chip 3 still must remain T, and this moment, piston body 2 top plan and valve seat 4 were that T adds suction valve chip 3 material thicknesses by the gap length that forms between cylinder 1 side surface.As seen after being with groove 6, the clearance volume that reduces is that suction valve chip 3 material thicknesses are multiplied by piston body 2 areas of surface except that groove 6.
Meanwhile, the exhaust port 7 on small boss 5 inserted valve seats 4 at piston body 2 tops has reduced the clearance volume brought by exhaust port 7, and the volume size that small boss 5 embeds is exactly the clearance volume that is reduced.
When the compressor air suction stage began, the gas in the clearance volume expanded, and the gas of expansion has occupied a part of aspirated volume.And adopt the piston body 2 of being with small boss 5 and groove 6, and realized the minimizing clearance volume, improved the volume of inspiration gas, improve compressor volume efficient, thereby improved the purpose of compressor overall efficiency.