JP4512193B2 - Reciprocating hermetic compressor and refrigeration / freezer using the same - Google Patents

Description

The present invention relates to a reciprocating hermetic compressor and a refrigeration / freezing apparatus using the same . The refrigerator / freezer of the present invention includes a refrigerator, a freezer, a refrigerator and a showcase.

  In recent years, compressors typified by refrigerators have been required to have higher performance for improving cooling performance, smaller size for improving volumetric efficiency, lower noise, lower cost, and higher reliability. Yes. As a conventional refrigerator compressor, a reciprocating hermetic compressor is widely used.

  As a conventional reciprocating hermetic compressor, for example, there is a hermetic compressor disclosed in Japanese Patent Application Laid-Open No. 2003-184551 (Patent Document 1).

  As shown in FIG. 10, this hermetic compressor is configured by accommodating an electric motor 22 and a compression mechanism 23 in a hermetic container 21. The compression mechanism portion 23 includes an eccentric portion 26 of the crankshaft 25, a connecting rod 29, a piston 28, a cylinder 27, and the like. The eccentric part 26 is provided at the upper end of the crankshaft 25 that is pivotally supported by the frame 24 so as to be eccentrically rotated. A piston 28 that reciprocates in the cylinder 27 is connected to the eccentric portion 26 via a connecting rod 29. The connecting rod 29 and the piston 28 are connected by a ball joint 30 as shown in FIG.

  The connecting rod 29 includes a spherical body portion 31, a ring portion 32 that is connected to the eccentric portion 26, and a connecting rod (rod portion) 33 that is fixed to both ends of the connecting rod 29. The piston 28 is provided with a ball seat 34 that fits the ball portion 31 of the connecting rod 29, and the connecting rod 33 fixedly connected to the ball portion 31 is connected to the ball seat 34 so as to be swingable. ing. On the back side of the ball seat 34, there is a recess 35 provided for the convenience of processing.

  Then, in order to cause the connecting rod 29 to oscillate as the piston 28 reciprocates, the ball joint 30 connecting the piston 28 and the connecting rod 29 has a slight gap e as shown in FIG. It has a configuration. That is, when the inner diameter of the ball seat 34 and the outer diameter of the ball portion 31 are exactly the same size, the ball seat 34 and the ball portion 31 cannot be slid. The relationship between the outer surface diameter d and the gap e is expressed by the following equation (1).

D = d + 2 · e (1)
Lubricating oil is scattered from an oil supply hole opened on the upper surface of the eccentric part 26, and the lubricating oil is supplied to the inlet side between the spherical body part 31 and the ball seat 34, thereby forming a lubricating film in the gap e. ing.

Japanese Patent Laid-Open No. 2003-184751

  In a conventional hermetic compressor, the sphere 31 is moved to the inlet side of the gap e during the intake process of the compression operation (see FIG. 13), and the sphere 31 is moved to the back of the gap e during the compression process of the compression operation. (See FIG. 14). In order to compress the inside of the cylinder 27 to a high pressure during the compression process, the spherical portion 31 is strongly pressed against the back side of the ball seat 34, and thereby the corners and the spherical portion of the recess 35 formed on the deep side of the ball seat 34. The outer spherical surface portion 31 comes into contact with the contact portion, and an extremely large contact stress is applied to the contact portion. As a result, it has been found that the ball seat 34 and the sphere 31 in the contact sliding portion are abnormally worn, and the reliability of the compressor is significantly reduced.

An object of the present invention is to provide a reciprocating hermetic compressor that can reduce contact stress between a ball seat of a piston and a spherical portion of a connecting rod and is excellent in reliability, and a refrigeration / refrigeration apparatus using the same. There is.

A first aspect of the present invention for achieving the above-mentioned object is a crankshaft for transmitting the rotational force of an electric motor, and a sphere having an inner spherical surface portion arranged on the crankshaft side while being arranged to reciprocate in the cylinder. A piston having a seat and an outer spherical portion having a diameter smaller than that of the inner spherical portion of the ball seat and having a spherical portion connected to the ball seat at one end and fitted to the crankshaft A reciprocating hermetic compressor having a connecting rod having a ring portion at the other end, and a recess for allowing the inner spherical surface processing tool to escape is formed in a central portion on the back side of the ball seat, and the entire outer periphery of the recess And an enlarged surface portion that is larger than the inner spherical surface portion is formed on the back side portion of the ball seat.

A more preferable specific configuration example in the first aspect of the present invention is as follows.
(1) to have a tapered surface which expands in the tangential direction from the circular arc surface of the inner spherical surface portion before Symbol enlarged surface.

The second aspect of the present invention is a refrigerated device with a reciprocating hermetic compressor of the first state-like.

ADVANTAGE OF THE INVENTION According to this invention, the contact stress of the ball | bowl seat of a piston and the spherical part of a connecting rod can be reduced, and a reciprocating type hermetic compressor excellent in reliability and a refrigeration / refrigeration apparatus using the same are provided. be able to.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. The same reference numerals in the drawings of the respective embodiments indicate the same or equivalent.
(First embodiment)
First, a first embodiment of the present invention will be described with reference to FIGS.

  The overall configuration of the reciprocating hermetic compressor of this embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a longitudinal sectional view of a reciprocating hermetic compressor according to a first embodiment of the present invention, and FIG. 2 is a sectional plan view showing a part of the compression mechanism portion of FIG. The reciprocating hermetic compressor of the present embodiment is used in a refrigerator-freezer, but can be applied to a refrigerator / freezer as described above.

  An electric motor 16 including a rotor 9 and a stator 11 and a compression mechanism portion 17 are provided inside the sealed container 12. The frame 4 supports the electric motor 16 and the compression mechanism 17 within the sealed container 12. The crankshaft 8 fixes the rotor 9 of the electric motor 16 and is supported by the frame 4. An eccentric portion 3 is provided at the upper end of the crankshaft 8. The ball joint portion 14 connecting the eccentric portion 3 and the piston 5 is provided to reciprocate the piston 1 with respect to the cylinder 5 and is composed of a ball seat 1a of the piston 1 and a sphere portion 2a of the connecting rod 2. Is done. The ball seat 1a is formed by a spherical surface opening to the crankshaft side. The connecting rod 2 includes a connecting rod 2b, a spherical portion 2a that is in solid contact with one end of the connecting rod 2b, and a ring portion 2c that is in solid contact with the other end of the connecting rod 2b. The ring part 2c is slidably fitted to the eccentric part 3. Further, the connecting rod 2 is formed with an oil supply hole 2d. The oil supply hole 2d is formed through the spherical body portion 2a, the connecting rod 2b, and the ring portion 2c, and communicates with an oil supply hole 15 formed in the eccentric portion 3.

  As described above, in the hermetic compressor used in the refrigeration cycle, the electric motor 16 and the compression mechanism 17 are housed in the hermetic container 12. The compression mechanism portion 17 is disposed on the upper end side of the crankshaft 5 that is pivotally supported by the frame 4, and is connected to the eccentric portion 3 that rotates eccentrically, the piston 1 that reciprocates and slides in the cylinder 5, and the eccentric portion 3. The connecting rod 2 includes a ring 2c and a spherical body portion 2a connected to the piston 8 integrally fixed by a connecting rod 2b. The connecting rod 2 and the piston 1 are connected to each other by a ball joint portion 14 that is a combination of the spherical portion 2a and the ball seat 1a of the piston 1.

  The piston 1 is installed in a reciprocating manner in a cylinder 5 installed on a frame 4. A connecting rod 2 is swingably attached to a ball seat 1a of the piston 1 via a spherical body portion 2a. The ring portion 2b of the connecting rod 2 is rotatably attached to the eccentric portion 3 of the crankshaft 8 via a bearing. The rotational force of the electric motor 16 comprising the stator 11 and the rotor 9 mounted in the sealed container 12 via the spring 10 is transmitted to the crankshaft 8, and the eccentric portion 8 causes the piston 1 to move to the cylinder 5 via the connecting rod 2. Reciprocate within. A cylinder head 7 is attached to the cylinder 5 via a valve plate 6, and a valve (not shown) opens and closes in synchronization with the reciprocating motion of the piston 1, thereby compressing fluid introduced from the outside of the sealed container 12. .

  Sliding between the piston 1 and the cylinder 5, between the connecting rod 2 and the eccentric part 3, between the crankshaft 8 and the bearing part of the frame 4, or between the ball seat 1a and the spherical part 2a The part is lubricated by lubricating oil (not shown) stored in the sealed container 12 when the compressor is in operation. Lubricating oil is pumped from the lower part of the hermetic container 12 through an oil supply hole 15 formed so as to communicate with the inside of the crankshaft 8 over the entire length of the shaft, and is supplied to the sliding portion. Yes. For pumping up the lubricating oil, there are a method of forcibly adding a trochoid pump and a method of supplying oil by operating the rotational force of the crankshaft 8 as a centrifugal pump. In this embodiment, a centrifugal pump is used.

  Next, specific structures of the piston 1 and the connecting rod 2 constituting the ball joint portion 14 of this embodiment will be described with reference to FIGS. FIG. 3 is a central sectional view of the piston 1 used in FIG. 2, and FIG. 4 is a plan view of the connecting rod 2 used in FIG.

  As shown in FIG. 3, a recess 1 b necessary for processing the ball seat 1 a is provided in the central portion on the back side of the ball seat 1 a of the piston 1. This recessed part 1b comprises the escape part of the tool which processes the ball seat 1a. An opening 1c is provided on the entrance side of the ball seat 1a. Further, an insertion groove 1d serving as an insertion port for inserting the spherical body portion 2a is provided on the inlet side of the ball seat 1a. The bottom of the insertion groove 1 d extends to the position of the maximum outer diameter of the ball seat 1 a and is provided symmetrically with respect to the center line of the piston 1. As shown in FIG. 4, the sphere part 2a of the connecting rod 2 has a plane cut part 2a1 from which a certain range in the vertical direction is removed from the spherical shape. The flat cut portion 2a1 is formed in parallel with the upper and lower ends of the ring portion 2c, that is, in parallel with the upper and lower surfaces.

  After aligning the positions of the insertion groove 1d of the piston 1 and the flat cut portion 2a1 of the sphere part 2a and inserting the sphere part 2a through the insertion groove 1d, the piston 1 and the connecting rod 2 are rotated by a substantially right angle. Thereby, the spherical part 2a does not come off due to the connection with the opening 1c having a smaller diameter, and the ball joint part 13 is completed.

  Next, a structure and manufacturing method that can reduce the contact stress of the sliding portion of the ball joint portion 14 of the present embodiment will be described with reference to FIGS. 5 is a cross-sectional plan view of the ball joint portion 14 used in FIG. 2, FIG. 6 is an enlarged view of portion A in FIG. 5, and FIG. 7 is a view showing a method for manufacturing the enlarged surface portion 1a2 in FIG.

As shown in FIG. 5, the ball seat 1a is disposed between a recess 1b on the back side and an opening 1c on the entrance side, and is composed of an inner spherical surface portion 1a1 and an enlarged surface portion 1a2. The inner spherical surface portion 1a1 is a portion that forms a main pressure receiving surface of the ball seat 1a, and is constituted by a spherical surface having a diameter D as shown in FIG. The enlarged surface portion 1a2 is formed on the back side portion of the ball seat 1a so as to be slightly larger than the inner spherical surface portion 1a1. The enlarged surface portion 1a2 has a tapered surface extending from the arc surface of the inner spherical surface portion 1a1 in the tangential direction toward the concave portion 1b (to the central portion side). In this embodiment, the tapered surface forms the entire enlarged surface portion 1a2. Accordingly, an enlarged surface is formed over the entire circumference outside the recess 1b. On the other hand, the outer spherical surface portion 2a2 of the spherical body portion 2a is a spherical surface having a diameter d. Outer spherical surface portion 2 a2 of spherical portion 2 a, as well as in the related art gap e between the inner spherical surface portion 1a1 of the ball seat 1a is formed, the gap applied between the enlarged surface portion 1a2 of the ball seat 1a e A gap that gradually increases is formed.

  After processing the inner spherical surface portion 1a1 between the recess portion 1b on the back side and the opening portion 1c on the inlet side, the rotational axis of the processing tool 18 is inclined with respect to the axis of the piston 1 as shown in FIG. With the piston 1 and the processing tool 18 rotated at different speeds together, the processing tool 18 is pressed against the back side of the inner spherical surface portion 1a1, and the enlarged surface portion 1a2 that expands from the inner spherical surface portion 1a1 to the back side portion of the ball seat 1a. Form. The outer surface of the processing tool 18 has the same shape as the final shape of the ball seat 1a. In this way, the ball seat 1a of the piston 1 can be easily manufactured. In addition, the dotted line in FIG. 7 shows the virtual circular arc part of the inner spherical surface part 1a1.

In the present embodiment, since there is a gap e between the inner spherical surface portion 1a1 of the ball seat 1a and the outer spherical surface portion 2a2 of the spherical body portion 2a, lubricating oil is supplied to the gap e to supply the spherical seat 1a and the spherical body. The part 2a can be smoothly slid. Further, even when the sphere part 2a is moved to the back side of the gap e and strongly pressed against the back side of the ball seat 1a during the compression process of the compression operation, an enlargement that expands from the inner spherical surface part 1a1 to the back side part of the ball seat 1a. Since the surface part 1a2 is formed, it can prevent contacting the corner | angular part of the recessed part 1b, and can reduce the contact stress of the ball seat 1a and the spherical body part 2a. As a result, the wear resistance of the sliding surface can be improved, and a reciprocating hermetic compressor with excellent reliability can be obtained. Furthermore, since the enlarged surface portion 1a2 is provided with a tapered surface that expands in a tangential direction from the arc surface of the inner spherical surface portion 1a1, the concentration of contact stress on the enlarged surface portion 1a2 is more reliably ensured even if the spherical portion 2a swings. Can be prevented, and further improvement in reliability can be achieved.
(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a cross-sectional view of the ball joint portion 14 of the reciprocating hermetic compressor according to the second embodiment of the present invention, and FIG. 9 is a cross-sectional view of the spherical portion 2a of the connecting rod 2 of FIG. The second embodiment is different from the first embodiment in the following points, and is basically the same as the first embodiment in other points.

  In the second embodiment, the spherical portion 2a of the connecting rod 2 is formed with a reduced surface portion 2a3 that is smaller than the outer spherical portion 2a2 at the tip side portion, and the spherical seat 1a of the piston 1 is an inner spherical portion that does not have an enlarged surface portion. 1a1. Also in the second embodiment, even when the sphere portion 2a is moved to the back side of the gap e and strongly pressed against the back side of the ball seat 1a during the compression process of the compression operation, it makes line contact with the corner portion of the recess 1b. Can be prevented, and the contact stress between the ball seat 1a and the spherical body portion 2a can be reduced.

Further, the reduction surface portion 2a3 of the second embodiment is entirely formed with a radius of curvature larger than that of the outer spherical surface portion 2a2, and a continuous portion to the outer spherical surface portion 2a2 is formed with a smaller radius of curvature than that of the outer spherical surface portion 2a2. Yes. This continuous portion is formed to be tangent to the circular arc surface of the outer spherical surface portion 2a2. With such a configuration, the concentration of contact stress in the enlarged surface portion 1a2 can be more reliably prevented even when the spherical body portion 2a swings, and the reliability can be further improved.

1 is a longitudinal sectional view of a reciprocating hermetic compressor according to a first embodiment of the present invention. It is a cross-sectional top view which shows a part of compression mechanism part of FIG. It is sectional drawing of the piston used for the compression mechanism part of FIG. It is a top view of the connecting rod used for the compression mechanism part of FIG. It is sectional drawing of the ball joint part of FIG. It is the A section enlarged view of FIG. It is sectional drawing which shows the processing method of the ball joint part of FIG. It is a longitudinal cross-sectional view of the ball joint part of the reciprocating hermetic compressor of the second embodiment of the present invention. It is sectional drawing of the spherical body part of the connecting rod used for FIG . It is a longitudinal cross-sectional view of the conventional reciprocating type hermetic compressor. Figure 1 is a sectional plan view showing a part of a compression mechanism of the 0. It is sectional drawing which expands and shows a part of ball joint part of FIG. It is a cross-sectional schematic diagram at the time of the suction | inhalation process of the ball joint part of FIG. It is a cross-sectional schematic diagram at the time of the compression process of the ball joint part of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Piston, 1a ... Ball seat, 1a1 ... Inner spherical surface part, 1a2 ... Enlarged surface part, 1b ... Recessed part, 1c ... Opening part, 1d ... Insertion groove, 2 ... Connecting rod, 2a ... Spherical body part, 2a1 ... Plane cut part, 2a2 ... outer spherical surface portion, 2b ... connecting rod, 2c ... ring portion, 2d ... relief of connecting rod, 3 ... eccentric portion, 4 ... frame, 5 ... cylinder, 6 ... valve plate, 7 ... cylinder head, 8 ... crankshaft , 9 ... rotor, 10 ... spring, 11 ... stator, 12 ... sealed container, 13 ... processing tool, 14 ... ball joint part, 15 ... oil supply hole, 16 ... electric motor, 17 ... compression mechanism part, 18 ... processing tool.

Claims (3)

A crankshaft that transmits the rotational force of the electric motor,
A piston that is arranged to reciprocate within the cylinder and that has a spherical seat having an inner spherical surface on the crankshaft side;
A spherical portion connected to the spherical seat having an outer spherical portion having a diameter smaller than that of the inner spherical portion of the spherical seat is provided at one end, and a ring portion fitted to the crankshaft is provided at the other end. A reciprocating hermetic compressor having a connecting rod;
A concave portion for allowing the inner spherical surface processing tool to escape is formed in the central portion on the back side of the ball seat, including a region extending over the entire outer periphery of the concave portion, and is expanded from the inner spherical surface portion to the back side portion of the ball seat. A reciprocating hermetic compressor having an enlarged surface portion.   2. The reciprocating hermetic compressor according to claim 1, wherein the enlarged surface portion has a tapered surface that expands in a tangential direction from an arc surface of the inner spherical surface portion.   A refrigerating / freezing apparatus using the reciprocating hermetic compressor according to claim 1.

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