JPH0633782B2 - Two cylinder rotary hermetic electric compressor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hermetic electric compressor having a rotary compression mechanism.

2. Description of the Related Art Conventionally, in order to obtain two compression spaces a and b, a compression mechanism portion of this type uses two cylinders, and a space between the cylinders c and d is used as shown in FIGS. In order to partition the intermediate plate e, the inner diameter e'of the intermediate plate e is set to be larger than the outer diameter of the crank pin part f'of the crank shaft f, and the piston g is rotatably disposed on the crank pin part. There is. The crankshaft f has a structure in which it is supported by an upper bearing end plate h and a lower bearing end plate i, and the piston end face g'has a length substantially determined by the difference in the inside diameter and the outside diameter of the piston. There is. Therefore, the piston end face g'contacting the bearing end plate has a seal length that is the difference in the inside and outside diameter dimensions of the piston, but the piston end face g "contacting the intermediate plate e is the inner diameter part e'of the intermediate plate and the crank. Since the outer diameter of the crank piston portion f'of the shaft f is set to be larger and the crank pin portion f'is eccentric, the end surface portion g "of the piston g has a portion closer to the inner diameter side than the inner diameter portion e'of the intermediate plate. It was in the form of protruding.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-mentioned configuration, the gas pressure acting on the piston end surface g ′ at the location formed by the bearing end plate and the piston end surface, and the location formed by the intermediate plate and the piston end surface. The gas pressure acting on the piston end face g ″ is as shown in FIG. 6, and the average value of the gas pressure acting on the piston end face direction differs depending on the end faces g ′, g ″, and the suction side space b and the crankshaft inner space j are Since the average value of the gas pressure acting on the piston end face g'is larger than the average value of the gas pressure acting on g'because of the pressure difference of, the piston g eventually contacts the bearing end plate in the direction of the piston end face. Thrust force is generated.

As a result, in the conventional structure, there is a problem that a frictional force is generated between the bearing end plate and the piston to reduce the efficiency of the compressor and induce wear of the piston bearing end plate.

The present invention provides a compressor structure capable of improving the performance of the compressor and improving the life and reliability thereof by adopting a configuration that does not generate the thrust force acting on the piston, which is seen in the conventional example. Is.

Means for Solving the Problems In order to solve the drawbacks seen in the above-mentioned conventional example, the present invention provides a contact area and a seal length formed between a piston and a bearing end plate, and a piston and an intermediate plate. The shape and dimensions of the piston end face are such that the piston is located inside the inner diameter portion of the intermediate plate at the point where the piston and the intermediate plate abut so that the area and seal length of the formed contact portion are the same. The end face region is provided with a step over the entire circumference of the piston end face, and the same shape and dimensions as the step provided on the piston end face of the abutting portion formed by the piston and the intermediate plate are also provided at the portion where the bearing end plate and the piston abut. Steps are provided on the piston, the intermediate plate on the lower end surface,
The area of each surface that comes into contact with the bearing end plate and the seal length are the same.

Operation With the above-mentioned configuration, the compressor of the present invention is configured such that the stepped portions having the same shape are provided on the piston and the lower end surface so that the shapes and sizes of the regions contacting the bearing end plate and the intermediate plate are the same. By doing so, the gas pressure acting on the upper end face of the piston and the gas pressure acting on the lower end face of the piston can be made equal, and as a result, the thrust force due to the difference in gas pressure acting in the piston end face direction is eliminated. It will be possible.

Therefore, it is possible to suppress the reduction of compressor efficiency and the occurrence of wear due to the frictional force due to the thrust force acting on the piston, and it is possible to improve the reliability such as the life which has been a problem in the past.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In the figure, reference numeral 1 is a closed container of a hermetic electric compressor, and a crankshaft 3 which is a component of the compression mechanism portion 2 is provided with an upper eccentric cam 3a and a lower eccentric cam 3b whose 180 ° eccentric positions are different, An upper piston 4a and a lower piston 4b are rotatably arranged on the eccentric cam portion. The crankshaft 3 has an upper bearing end plate 5a and a lower bearing end plate 5b.
And is rotatably housed in the cylinder 6 together with the pistons 4a and 4b. A vane for accommodating an upper partition vane (not shown) and a lower partition vane (not shown) for partitioning the compression spaces 7 and 8 into the suction side spaces 7a, 8a and the compression side spaces 7b, 8b in the cylinder 6. A groove (not shown) is provided, and an intermediate plate 9 for partitioning the upper piston 4a, the upper partition vane, the lower piston 4b and the lower partition vane, and forming an upper compression space 7 and a lower compression space 8 is provided. ing.

Further, the diameter of the inner diameter portion 9a of the intermediate plate 9 is equal to the crankshaft 3
In order to install it in the middle of 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 made slightly larger than the outer diameter of the eccentric cams 3a, 3b.

A discharge port (not shown) is provided on each of the upper bearing end plate 5a and the lower bearing end plate 5b, and a discharge valve (not shown) and a stopper (not shown) are provided. , The bearing end plates are covered so that the discharge mufflers 10a, 1
0b is provided.

Further, the upper bearing end plate 5a, the lower bearing end plate 5b, and the cylinder 6 are provided with a discharge passage (not shown) for communicating the upper discharge muffler inner space 11a with the lower discharge muffler inner space 11b, and the upper bearing. The end plate 5a, the lower bearing end plate 5b, the cylinder 6, and the upper discharge muffler are provided with a discharge passage (not shown) that connects the lower discharge muffler inner space 11b and the closed container inner space 1a.

Further, the cylinder 6 is provided with a suction port 6a,
The airtight container 1 is provided with a discharge pipe 1b, and a stator 12a of the electric motor unit 12 is provided therein.

Further, as shown in FIG. 2, the end surfaces of the pistons 4a and 4b have steps 4c 'and 4d over the entire inner circumference of the piston end surfaces at positions where the end surfaces 4c and 4d of the pistons 4a and 4b are located inside the inner diameter portion 9a of the intermediate plate 9. ′ Is provided, and the piston end surface portions 4e and 4f that come into contact with the bearing end plates 5a and 5b are also
Step portion 4 on the end surface of the piston that contacts the intermediate plate 9
The steps 4e 'and 4f' having exactly the same dimensions as those of c'and 4d 'are provided.

In addition, the step is formed by cutting the inside of the piston end surface by c so as to be easily manufactured.

In the above configuration, when the electric motor unit 12 is driven completely, the crankshaft 3 rotates, and the upper piston 4a and the lower piston 4b roll in the compression spaces 7 and 8 while being 180 degrees out of phase with each other. Further, the refrigerant in the refrigeration cycle having a well-known structure is sucked from the suction port 6a, compressed in the cylinder 6 as the process progresses, and discharged ports (not shown) provided in the bearing end plates 5a and 5b, respectively. The discharge valve (not shown) is pushed up to move into the discharge muffler inner spaces 11a and 11b, respectively, and 180 degrees out of phase during one rotation of the crankshaft 3.
It is discharged once.

The gas discharged into the upper discharge muffler inner space 11a passes through the discharge passage (not shown) and reaches the discharge muffler inner space 11b, and the discharge muffler inner space 11b.
Along with the gas discharged into the closed container inner space 1a through the discharge passage (not shown).
It is discharged again through b into the refrigeration cycle.

At this time, as shown in FIG. 3, the suction side 7a is provided between the intermediate plate 9 and the piston end faces 4c, 4d, 4c'4d '.
Alternatively, the thrust force acts by the gas pressure in the compression side space 7b, the crankshaft 3, and the inner space 13 of the piston 4a or 4b. Also, the bearing end plates 5a, 5b and the pistons 4a, 4
Similarly, a thrust force is generated at the contact points 4e, 4f of b 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, 4c ', 4d'. However, the stepped portion 4 is also formed on the piston end surfaces 4e and 4f that come into contact with the bearing end plates 5a and 5b.
Steps 4e 'and 4f' having the same size and shape as c'and 4d '
Is provided, the piston end surface portions 4e, 4f, 4
The thrust forces acting on e'and 4f 'have the same magnitude as the thrust forces acting on the piston end surface portions 4c, 4d, 4c', 4d ', but the directions are opposite to each other.
It can be maintained throughout the entire rotation of b, and consequently the thrust force acting on the piston can be eliminated.

EFFECTS OF THE INVENTION As is apparent from the above-described embodiments, the two-cylinder rotary hermetic electric compressor of the present invention has a configuration capable of suppressing the generation of thrust force acting on the piston, and has the conventional problems. It has various advantages such as reduction of compressor efficiency due to generation of frictional force due to thrust force, wear of bearing end plate piston, etc., and improvement of reliability such as compressor life. Is. Also, 4c ', 4
The same effect can be obtained without the C cut portion of d '.

[Brief description 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 a compression mechanism portion of the compressor, and FIG. 3 acts on a piston in the compressor. Gas pressure relationship diagram, FIG. 4 is a side sectional view of a two-cylinder rotary compressor showing a conventional example, FIG. 5 is a sectional view of a compression mechanism portion of the compressor, and FIG. 6 acts on the compressor piston. It is a gas pressure relationship diagram. 1 ... airtight container, 2 ... compression mechanism part, 3a ... upper eccentric cam, 3b ... lower eccentric cam, 4a ... upper piston,
4b ... lower piston, 4c, 4d, 4e, 4f ... piston end face portion, 4c ', 4d', 4e ', 4f' ... piston end face step portion, 5a ... upper bearing end plate, 5b ... lower bearing End plate, 6 ... Cylinder, 7 ... Upper compression space, 8
...... Lower compression space, 9 ...... Intermediate plate, 9a ...... Intermediate plate inner diameter portion, 10a ...... Upper discharge muffler, 10b
...... Lower discharge muffler, 11a, 11b ...... Internal space of the discharge muffler 12 ...... Electric motor, 13 ...... Inner space between crankshaft and piston.

Claims (1)

[Claims] 1. An electric motor and a rotary compression mechanism part driven by the electric motor are arranged in a closed container, and two eccentric cams are attached to a crankshaft which is a component of the rotary compression mechanism part by 180 °. The two pistons are provided at different angles and are rotatably disposed on the eccentric cam portion;
It has two cylinders for accommodating pistons and a bearing end plate that supports the crankshaft and is provided so as to close the suction and compression spaces, and the closed space is divided into a suction side space and a compression side space. Two partition vanes for partitioning are provided, and an intermediate plate having an inner diameter larger than the diameter of the eccentric cam portion of the crankshaft is provided in the cylinder so as to partition the upper compression space and the lower compression space in the cylinder. In the compressor, the seal length and area of the end face portion where the piston contacts the bearing end plate between the piston and the bearing end plate, and the seal length and area of the end face portion where the piston contacts the intermediate plate between the piston and the intermediate plate. A two-cylinder rotary hermetic electric compressor whose upper and lower end faces have the same size and shape.