JPS63235688A - Two-cylinder revolution type sealed type motor-driven compressor - Google Patents

Abstract

PURPOSE:To improve the performance and reliability of a compressor by setting the area and the sealing length of the contact surfaces of an intermediate plate and a bearing plate on the upper and lower edge surfaces of a piston equal each other, thus eliminating the generation of a thrust power acting onto the piston. CONSTITUTION:When an electric motor part is driven, a crankshaft 3 is revolved, and the upper and lower pistons 4a and 4b shift in the respective compression spaces, keeping each different phase. Therefore, coolant is compressed in a cylinder 6 and discharged into the spaces 11a and 11b in the mufflers. In this case, step differences 4c' and 4d' are formed, inside in comparison with the inner diameter part 9a of an intermediate plate 9, on the edge surfaces of the pistons 4a and 4b. Further, the same step differences 4e' and 4f' are formed also on the edge surfaces in contact with the bearing edge plates 5a and 5b of the pistons 4a and 4b. Therefore, a thrust power acting onto each edge surface can be set with an equal magnitude in the opposite direction.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a hermetic electric compressor having a rotary compression mechanism.

2. Description of the Related Art Conventionally, as shown in FIGS. 4 to 6, this type of compression mechanism uses two cylinders in order to obtain two compression spaces -1b, and an intermediate space between the cylinders c and d. The inner diameter part e' of the intermediate plate e is separated by the crankshaft f.
The piston 9 is set to be larger than the outer diameter of the crank pin portion f', and is rotatably disposed on the crank pin portion.

The crankshaft f is supported by an upper bearing end plate and a lower bearing end plate, and the piston end face 9' has a length approximately determined by the difference in piston inner and outer diameter dimensions. There is. Therefore, the piston end face 9 in contact with the bearing end plate
' has a seal length equal to the difference in inner and outer diameter dimensions of the piston, but the end surface of the piston in contact with the intermediate plate ' is
Since the inner diameter part of the intermediate plate is set larger than the outer diameter of the crank piston part f' of the crankshaft f, and the crank pin part f' is eccentric, the end face part q' of the piston 9 is partially It was in a shape that protruded to the inside diameter side from the inside diameter part l of the plate.

Problems to be Solved by the Invention However, with the above configuration, gas pressure acts on the piston end surface at the location formed by the bearing end plate and the piston end surface, and gas pressure acts on the piston end surface at the location formed by the intermediate plate and the piston end surface. A thrust force is generated on the piston end face C in the direction of the end face so as to come into contact with the bearing end plate.

As a result, in the conventional configuration, a frictional force is generated between the bearing end plate and the piston, which reduces compressor efficiency and causes wear of the piston bearing end plate.

The present invention provides a compressor structure that makes it possible to improve the performance, life and reliability of the compressor by having a configuration that does not generate the thrust force that acts on the piston as seen in conventional examples. It is.

Means for Solving the Problems In order to solve the drawbacks seen in the above-mentioned conventional examples, the present invention has been developed to improve the area and seal length of the abutting part formed between the piston and the bearing end plate, and the seal length between the piston and the intermediate plate. In order to have the same area and seal length of the abutting part, the shape and dimensions of the piston end surface are adjusted so that the area where the piston and the intermediate plate abut, where the piston is located further inside than the inner diameter of the intermediate plate. A step is provided in the piston end surface region over the entire circumference of the piston end surface, and the same shape as the step provided on the piston end surface of the contact portion formed by the piston and the intermediate plate is also provided at the place where the bearing end plate and the piston contact, A step is provided in the dimensions so that the areas and seal lengths of the surfaces in contact with the intermediate plate on the upper and lower end surfaces of the piston and the bearing end plate are the same.

Effect With the above configuration, the compressor of the present invention has a step having the same shape on the upper and lower end surfaces of the piston, respectively, so that the regions that contact the bearing end plate and the intermediate plate have the same shape and dimensions. As a result, it becomes possible to eliminate the thrust force due to the difference in gas pressure acting in the direction of the end surface of the piston.

Therefore, it is possible to improve the reliability of the thrust force acting on the piston.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 3.

In the figure, 1 is a closed container of a closed type electric compressor, and a crankshaft 3, which is a component of a compression mechanism section 2, is provided with an upper eccentric cam 3a and a lower eccentric cam 3b whose eccentric positions are different by 180 degrees. An upper piston 4g and a lower piston 4b are rotatably disposed in the eccentric cam portion. Further, the crankshaft 3 has an upper bearing end plate 5a and a lower bearing end plate 6b.
A smaller vane structure (not shown) is provided together with the pistons 4a and 4t, and an upper piston 4m, an upper partition vane, a lower piston 4b, and a partition 9 separating the lower partition vane, and a lower compression space 7. An intermediate grate 9 for forming a lower compression space 8 is provided.

Further, the diameter of the inner diameter portion 9a of the intermediate grate 9 is equal to that of the crankshaft 3.
In order to install the intermediate plate 9 between the upper eccentric cam 3a and the lower eccentric cam 3b, the diameter of the inner diameter portion 9a of the intermediate plate 9 is slightly larger than the outer diameter of the eccentric cams 3m and 3b.

Further, the upper bearing end plate 5a and the lower bearing end plate 5b are each provided with a discharge port (not shown), and a discharge valve (
(not shown) and a stopper (not shown) are provided on each bearing end plate as if covering the discharge mufflers 10a, 10.
b is provided.

Further, the upper bearing end plate 5a, the lower bearing end plate 6b, and the cylinder 6 are provided with a discharge passageway which connects the upper discharge muffler inner space 11m and the lower discharge muffler inner space 11b, and the upper bearing end plate 5 The upper and lower bearing end plates 6b, the cylinder 6, and the 7-part discharge muffler are provided with a discharge passage (not shown) that communicates the lower discharge muffler interior space 11b with the closed container interior space 1a.

Further, the cylinder 6 is provided with a suction port 6-.
The closed container 1 is provided with a discharge pipe 1b, and a stake 12m of the electric motor section 12 is provided.

Steps 4G' and 4d' are provided over the entire inner periphery of the piston end face in the inner diameter part 9a of the inner diameter part 9a. Steps 4 and 9 have exactly the same dimensions as the step portions 4c' and 4t' on the end surface of the piston that come into contact with 9.
14f is provided.

Further, the step is formed by C-cutting the inside of the piston end face for ease of manufacturing.

In the above configuration, when the electric motor section 12 is fully driven, the crankshaft 3 rotates, and the upper piston 4a and the lower piston 4b roll within the compression space 7.8 while being out of phase with each other by 180 degrees. The refrigerant in the refrigeration cycle having a well-known structure is sucked in from the suction port 6s, compressed in the cylinder 6 as the process progresses, and discharged from the discharge boats (
(not shown) and pushes up a discharge valve (not shown) to discharge into the discharge muffler inner spaces 11m and 11b, respectively, once with a 1808 phase difference during one rotation of the crankshaft 3. .

Further, the gas discharged into the upper discharge muffler inner space 11a passes through the discharge passage (not shown), reaches the discharge muffler inner space 11b, and reaches the discharge muffler inner space 11b.
Together with the gas discharged to
b and is discharged again into the refrigeration vehicle.

At this time, as shown in FIG. 3, between the intermediate plate 9 and the piston end faces 4c, 4d, 4c'4d, there is a suction side 7a or a compression side space 7b, and a crankshaft 3 and a piston 4m or 4c.
A thrust force acts due to the gas pressure in the inner space 13 of b. Also, bearing end plates 5m, 5b and pistons 4a, 4b
Similarly, a thrust force is generated in the direction opposite to the thrust force direction due to the gas pressure acting between the intermediate plate 9 and the piston end faces 4c, 4d, 46', 4d at the contact points 4e and 4f. The stepped portion 4c' is also located at the piston end face 46.4f that comes into contact with the bearing end plates 5g and 5b.
, 4d' are provided with stepped portions 4e' and 4f' having the same size and shape as the piston end surface portion 4e.

The thrust force acting on 4f, 4s/, 4f' is the same in magnitude as the thrust force acting on the piston end face portions 4c, 4d, 4c', 4d'. As is clear from the example, the two-cylinder rotary hermetic electric compressor of the present invention enables a configuration that suppresses the generation of thrust force acting on the piston, which has been a problem in the past. Eliminates the reduction in compressor efficiency due to the generation of frictional force due to thrust force and the occurrence of wear on the bearing end plate piston, etc.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of a rotary hermetic electric compressor according to an embodiment of the present invention, Fig. 2 is a sectional view of the compression mechanism of the compressor, and Fig. 3 is a sectional view of the compressor acting on the piston in the compressor. Figure 4 is a side cross-sectional view of a conventional two-cylinder rotary compressor, Figure 5 is a cross-sectional view of the compression mechanism of the compressor, and Figure 6 is a diagram showing the action on the compressor piston. It is a gas pressure relationship diagram. 1... Airtight container, 2... Compression mechanism section,
3a... Upper eccentric cam, 3b... Lower eccentric cam, 4m... Upper piston, 4b...
...lower piston, 4c, 4d. 4., 4f...Piston end surface, 4c', 4d
', 46'4 f'...I piston end face step,
5a... Upper bearing end plate, 5b... Lower bearing end plate, 6... Cylinder, 7... Upper compression space, 8...・Lower compression space, 9...
...Intermediate plate, 9 heat...Inner diameter part of intermediate plate, 1σr...Upper discharge muffler, 10b...
・Lower discharge muffler, 11, 11b...Discharge muffler inner space 12...Electric motor, 13...
・Inner space between the crankshaft and piston. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4 Figure 5

Claims (1)

[Claims] An electric motor and a rotary compression mechanism driven by the electric motor are disposed in a sealed container, and two eccentric cams are installed on the crankshaft, which is a component of the rotary compression mechanism, with a mounting angle shifted by 180 degrees. Also, two pistons rotatably disposed in the eccentric cam portion, two cylinders housing the two pistons, and a cylinder configured to support the crankshaft and close suction and compression spaces. The cylinder has a bearing end plate provided in the cylinder, two partition vanes are arranged to partition the closed space into a suction side space and a compression side space, and the cylinder has an inner diameter dimension larger than the diameter of the eccentric cam part of the crankshaft. In a compressor in which an intermediate plate is arranged to partition an upper compression space and a lower compression space in the cylinder, the seal length and area of the end face between the piston and the bearing end plate where the piston abuts the bearing end plate. and the seal length of the end face between the piston and the intermediate plate where the piston contacts the intermediate plate,
A two-cylinder rotary hermetic electric compressor with dimensions and shape of the upper and lower end surfaces of the piston so that the area is the same.