KR100783231B1 - Closed type compressor - Google Patents

Abstract

An object of the present invention is to provide a compressor which improves efficiency by reducing slip movement loss.

In a hermetic compressor in which a compression element and a transmission element are accommodated in a sealed container, and a crankshaft 7 and a piston 4 driven by the transmission element are connected in a ball joint structure by a connecting rod 2, the ball joint structure is a piston It is comprised by the durable surface 4a provided in (4), the concrete part 2a provided in the connecting rod 2, and the rotation control part 10d which is a member separate from the piston 4 and the connecting rod 2; The rotation restricting portion 10d can be provided on the piston 4 side instead of the connecting rod 2 side, and regulates the relative rotation of the piston 4 and the connecting rod 2. Moreover, the iron type sintered material sealed with the oxide film for the piston 4 and the connecting rod 2 was used.

Compressor, piston, inner surface, regulating part, crankshaft, concrete part

Description

Hermetic compressor {CLOSED TYPE COMPRESSOR}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to hermetic compressors for use in refrigerators and room air conditioners, and more particularly to hermetic compressors having reciprocating pistons.

In a hermetic compressor having a reciprocating piston, a structure is used in which a crankshaft and a piston are connected by a connecting rod, and the movement of the shaft that rotates is converted into a reciprocating motion. Among these, as a connection structure of a piston and a connecting rod, the structure connected by a radial bearing is known, as described in patent document 1. As shown in FIG.

Patent Document 1 uses a piston pin at a connection portion between a piston and a connecting rod, and has a structure in which both are connected as a bearing structure in which the piston pin is an axis.

Moreover, as another connection structure of a piston and a connecting rod, what is called a ball joint structure connected with spherical bearings like patent document 2 and patent document 3 is known. As what is connected as a ball joint structure, the structure which shape | molded the durable surface provided in the piston by plastic working like patent document 2 is known. In addition, in Patent Document 3, a portion of the inner surface of the piston and a portion of the outer surface of the connecting rod are deleted together, and the connecting rod and the piston are connected by rotating the piston after inserting the outer portion of the connecting rod into the inner portion of the piston.

In addition, in patent document 2, both or one of nitriding treatment and manganese phosphate treatment are given to the spherical support sheet of a ball joint structure, and high carbon chromium steel is used for the spherical surface. In patent document 4, the example which sintered the piston connected by the ball joint type | mold is shown.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2004-27969

[Patent Document 2] Japanese Patent Application Laid-Open No. 2003-214343

[Patent Document 3] Japanese Unexamined Patent Publication No. 2003-184751

[Patent Document 4] Japanese Patent Application Laid-Open No. 64-69862

In the above-mentioned prior art example, patent document 1 performs connection of a piston and a connecting rod with a piston pin, but this connection structure has a piston pin inserted in the piston side as a bearing part, and has a bearing part in a connecting rod side. Therefore, when the shaft of the piston side is inserted inclined to the bearing of the connecting rod side, there existed a problem regarding sliding. In other words, the sliding portion between the piston pin and the connecting rod becomes local, and at this time, the contact surface pressure of both becomes excessive, which may cause a decrease in reliability due to wear of the sliding portion. In Patent Literature 1, the supply of lubricating oil is stabilized to improve the reliability, but there is no solution to localization of the sliding part generated due to the bearing structure.

On the other hand, patent document 2 and patent document 3 employ | adopt the structure which connects a piston and a connecting rod by the ball joint system. According to the connection of the ball joint method, sliding and abrasion between the piston pin and the connecting rod do not become a problem as in Patent Document 1.

Since patent document 2 shape | molds the account provided in a piston by plastic working, it does not generate | occur | produce the problem mentioned above, but it was the structure which may produce a problem in the sliding movement between a piston and a connecting rod. That is, since it processes in the direction which closes a part part in order to ensure a connection state, the passage | path of the lubricating oil supplied to a connection part may become narrow, and lubricating oil may not flow enough. Therefore, the inflow and outflow of lubricating oil to a connection part cannot fully be secured, and there exists a possibility of causing the temperature rise and damage of a spherical bearing part.

On the other hand, patent document 3 has a structure which has the flat part which cut | disconnected a part of the concrete part of a connection rod, and connects both by rotating after inserting the concrete part of a connection rod to the piston side account. This configuration can secure a space for lubricating oil supply, but there is a problem that the connection is lost when the sphere rotates relative to the piston. In Patent Document 3, the release control member is provided to prevent the release of the connection. For example, in the rotation control member having the structure shown in Fig. 12 of Patent Document 2, the stopper, which is the rotation control member, slides with the piston to make noise. This is likely to occur. Further, in the structures of Figs. 13 and 15, because the stopper is held only by the frictional force, there is a possibility that the frictional force changes when the piston rotates during operation, and the stopper of the connecting rod may come off.

Moreover, when high carbon chromium steel was used for the spherical surface (ball) like patent document 2, since the hardness of the high carbon chromium steel was high, there existed a problem in workability. That is, a material not only having high wear resistance but also excellent workability has been demanded. In addition, when such a hard material is used, it is difficult in patent document 2 to integrally form a connecting rod from the problem of workability. In order to make the shape of the spherical surface which becomes a connection part with a piston close to a true circle, the process of forming a rod part and a concrete part separately, and connecting them after that will be needed. At this time, production efficiency may fall.

On the other hand, if the concrete portion and the rod portion are integrally formed, it is difficult to hold the precision of the concrete portion, so that the loss is likely to occur in the piston sliding surface, and there is a fear of causing a decrease in reliability due to the progress of wear. there was.

The present invention is to solve the problems that can occur in the conventional example as described above, in the ball joint type hermetic compressor connecting the piston and the rod by the spherical bearing, to ensure the reliability or reduce the sliding loss efficiency It is an object of the present invention to provide a compressor which is improved.

In order to achieve the above object, it is a hermetic compressor in which a compression mechanism and an electric motor are accommodated in a hermetic container, and a crank shaft and a piston driven by an electric motor are connected in a ball joint structure by a connecting rod,

The ball joint structure of the present invention is composed of an inner surface provided in the piston, a spherical portion provided in the connecting rod, and a rotation restricting portion that is a separate member from the piston and the connecting rod, and the rotation restricting portion is installed in the piston to be relatively relative to the piston and the connecting rod. The rotation was regulated.

Moreover, in order to achieve the said objective, this invention is a crankshaft which a compression mechanism and an electric motor are accommodated in a hermetically sealed container, and transmits the rotational force from an electric motor, the piston opened to this crankshaft side, and has a durable surface in this opening, And a connecting rod having a rod portion for connecting both ends thereof, and having a spherical portion connected to the inner surface as one end and a bearing portion for connecting the other end to a crankshaft, wherein the center angle of the circular arc in the horizontal direction of the inner surface is vertical. It is formed larger than the center angle of the arc of the arc, the spherical portion is a hermetic compressor having a small dimension which is smaller than the opening dimension in the horizontal direction of the inner surface, the inner surface and the spherical portion is connected in a ball joint structure,

A rotation restricting portion for restricting relative rotation between the connecting rod and the piston at a position opposite the small dimension portion,

This rotation restricting portion can be installed on the piston, and at the time of the relative rotation, it is allowed to contact the small dimension of the sphere.

Further, in the hermetic compressor, the small dimension is formed by planar portions parallel to each other, and the dimensions between the planar portions have the same dimensions as those having a dimension smaller than the diameter of the arc, and the rotation restricting portion It was set as the convex shape which has a planar shape facing the said planar part.

Moreover, an elastic part is provided between the said rotation control part and the inner peripheral surface in the opening of a piston, and the rotation control part is hold | maintained by the elastic force from this elastic part.

Moreover, this elastic part and the rotation restricting part are provided as a part of the fall prevention member which consists of one member, and this fall prevention member has the extending | stretching part extended toward the inner peripheral surface in the opening of a piston, and the edge part of this extending | stretching part is a piston inner peripheral surface. It was set as the structure hold | maintained by entering into the groove | channel provided in the.

Moreover, the outer peripheral surface which contacts the inner peripheral surface of a piston in the said elastic part was made into the curved surface shape, and it was set as the spring member of the shape along the inner peripheral surface of a piston.

The elastic portion and the rotation restricting portion are provided on both sides of the connecting rod above and below, and the dimension between the upper rotation restricting portion and the lower limiting rotation restricting portion is made larger than the small dimension portion, and the elastic portion is such a rotation restricting portion. It was assumed that a force was generated in the direction of sandwiching the sphere.

In addition, the spring member which comprises an elastic part shall be comprised by the spring arrange | positioned in the circumferential direction of the inner peripheral surface of a piston.

Moreover, between the elastic part and rotation control part located upward, and the elastic part and rotation control part located below, it is connected by the support part, and such an elastic part, the rotation control part, and the support part shall be comprised by one member. .

In addition, the extending | stretching part of a fall prevention member shall be provided in the support part.

In addition, in order to achieve the above object, the ball joint structure of the present invention is composed of an inner surface provided on the piston, and a spherical portion provided on the connecting rod, the iron-based element is sealed by the oxide film It was settled.

And the said durable surface and the said concrete part were made into the iron-based sintered material which carried out the nitride process, or the said concrete part was made into the iron-based sintered material which performed the sealing process and nitriding process by the oxide film.

In the hermetic compressor of any of the above, the hardness of the rotation restricting portion is made larger than the surface hardness of the spherical portion.

In addition, the connecting rod was Vickers hardness, the internal hardness was lower than the portion close to the surface.

In addition, a hydrocarbon refrigerant is used as the refrigerant compressed by the compression mechanism, and an ester synthetic oil is used as the lubricating oil.

According to the present invention, it is possible to reduce the sliding loss of the ball joint portion and to provide a compressor with improved efficiency.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described using drawing.

1 is a longitudinal sectional view of a hermetic compressor according to one embodiment of the present invention. The hermetic compressor of the present embodiment is a reciprocating compressor in which the piston 4 reciprocates in the cylinder 1 integrally formed with the bearing portion 1a and the frame 1b provided in the hermetic container to form a compression mechanism. The stator 5 and the rotor 6 which comprise an electric motor as an electric motor are provided in the lower part of the frame 1b, and the crank pin 7a is provided in the position eccentric from the rotation center of the crankshaft 7. .

The crankshaft 7 extends from the lower part of the frame 1b to the upper part through the bearing part 1a of the frame, and is installed so that the crank pin 7a may be located above the frame 1b. The lower part of the crankshaft 7 is directly connected with the rotor 6, and the crankshaft 7 rotates by the power of an electric motor. The crank pin 7a and the piston 4 are connected by the connecting rod 2, and the piston 4 reciprocates through the crank pin 7a and the connecting rod 2. As shown in FIG.

That is, in the hermetic compressor of the present embodiment, a compression mechanism such as the cylinder 1 and the piston 4 and an electric motor such as an electric motor are accommodated in the hermetic container, and the crank shaft 7 transmits the rotational force from the electric motor. On the premise that Although the connection structure of the connecting rod 2 and the piston 4 is mentioned later, the piston 4 opens to the crankshaft 7 side, and has the durable surface in this opening.

Next, the piston 4 will be described with reference to FIGS. FIG. 2 is a detailed view of the inner structure of the piston 4, and is a view of the piston 4 seen from the crankshaft 7 side. The piston 4 of this embodiment opens to the crankshaft 7 side, and has the durable surface 4a inside the opening. 3 is a cross-sectional view taken along the line A-A of FIG. 2, and FIG. 4 is a cross-sectional view taken along the line B-B of FIG.

FIG. 2 is a view of the piston 4 viewed from the crankshaft 7 side as described above. In the state where the piston 4 can be installed in the hermetic compressor, the up and down direction of FIG. 2 is hermetically sealed in FIG. It coincides with the up and down direction of the compressor. In addition, the left-right direction of FIG. 2 becomes the horizontal direction which connects front and inside in FIG. Therefore, Fig. 3 shows a state where the AA cross section, which is the cross section of the horizontal plane, is seen from the upper side or the bottom side of the piston 4, and Fig. 4 shows the BB cross section, which is the cross section of the vertical direction, viewed from the left or right side of the piston 4 To illustrate. In FIG. 3, the lower side in the drawing is the inside of the piston 4, and in FIG. 4, the right side in the drawing is the inside of the piston 4.

The inner surface 4a of the piston 4 constitutes the bearing structure which receives the outer surface of the concrete part provided in the front-end | tip part of the connecting rod 2, as mentioned later, In the AA cross section, the outer surface of the connecting rod 2 is formed. The shape is enclosed at an angle of 180 degrees or more. Therefore, the outer peripheral surface of the connecting rod 2 surrounds and supports the inner surface 4a of the piston 4 so that the connecting rod 2 and the piston 4 are connected. On the other hand, in the B-B cross section, the outer peripheral surface of the connecting rod 2 is formed at an angle of 180 degrees or less, and in the B-B cross section, the sliding area is smaller than that of the A-A cross section.

Thus, since the center angle of the circular arc in the horizontal direction (AA cross section) of the durable surface 4a was made larger than the center angle of the circular arc in the vertical direction (BB cross section), the sliding area is a vertical direction. It has a ball joint structure with a small cross section. Therefore, the lubricating oil easily passes, and also the path itself through which the lubricating oil passes, the lubricating oil flows in and out easily at the connecting portion, and wear and tear due to the sliding movement can be reduced. Moreover, since there is a recessed portion inside the durable surface 4a, the sliding surface can be made smaller.

2 to 4, a space exists above and / or below the inner surface 4a located inside the inner circumference of the piston 4, and the space preventing member 10 ) Is installed. The fall prevention member 10 and its installation state are mentioned later.

Next, the connecting rod 2 connected with the piston 4 is demonstrated using FIG. The connecting rod 2 of the present embodiment has a spherical portion 2a connected to the inner surface 4a of the piston 4 as one end, and the other end as a bearing portion connected to the crankshaft 7, and connects both ends thereof. It is a structure which has the rod part 2c, and FIG. 5 is a perspective view of the connecting rod 2 provided with this structure.

As shown in the drawing, the connecting rod 2 includes a spherical portion 2a inserted into the inner surface 4a of the piston 4, a radial bearing portion 2b inserted into the crank pin 7a, and a spherical portion ( The rod part 2c which connects 2a) and the radial bearing part 2b is comprised, and the outer peripheral surface of the concrete part 2a has the structure which a part of sphere was cut out.

The part where this part of the sphere was cut out becomes a dimension part smaller than the outer diameter dimension of a sphere, and the connecting rod 2 and the piston 4 are connected using this small dimension part. The connection of both is mentioned later. In the present embodiment, small dimension portions are formed by planar portions parallel to each other, and the dimension between the two planar portions is a dimension smaller than the outer diameter dimension of the sphere (that is, the diameter of the arc).

Thus, since the structure has a flat part on one side and the other side of the outer surface of the concrete part 2a, even if the piston 4 and the connecting rod 2 are connected, the path | route which a lubricating oil passes is short, and since lubricating oil flows easily, Therefore, it becomes a structure which can supply a lubricating oil to a sliding part.

In connecting the connecting rod 2 and the piston 4, the flat part provided in the outer peripheral surface of the specific part 2a of the connecting rod 2 is used. As shown in FIG. 3, the inner surface 4a of the piston 4 has the shape which encloses the outer surface of the concrete part 2a of the connecting rod 2 at an angle of 180 degrees or more, The opening dimension L of the inner surface 4a is smaller than the outer diameter of the outer surface of the concrete part 2a. On the other hand, the dimension between two planar parts of the outer peripheral surface of the concrete part 2a is set smaller than the opening dimension L of the durable surface 4a. The part of this opening dimension L is a clearance gap for inserting the concrete part of the connecting rod 2, and the small dimension part mentioned above has shown the part smaller than this opening dimension L. As shown in FIG.

In the present embodiment, two planar portions provided on the outer peripheral surface of the spherical portion 2a are provided in substantially parallel, and both planar portions can be inserted into the openings of the inner surface 4a. After the connecting rod 2 is inserted into the inner surface 4a of the piston 4, the connecting rod 2 and the piston 4 are relatively rotated and both are connected. In addition, in this embodiment, although the structure which provided two planar parts to the outer peripheral surface of the concrete part 2a was not necessarily limited to this, It is smaller than the opening dimension L of the internal surface 4a so that both may be connected. You may provide a dimension part in the outer peripheral surface of the concrete part 2a.

If the connecting rod 2 and the piston 4 connected in this way have no relative rotation between them, the opening dimension of the inner surface 4a is smaller than the outer diameter of the concrete portion 2a, and thus the sliding portion can be made smaller. have.

However, when both are relatively rotated by an action such as an impact, the connection between the connecting rod 2 and the piston 4 is released, so in this embodiment, the release preventing member 10 is removed to prevent the connection from being disconnected. Equipped.

The fall prevention member 10 is demonstrated using FIG. 6 and FIG. Fig. 6 is a perspective view of the release preventing member 10 of the present embodiment, and Fig. 7 is a perspective view showing a state of the piston 4 and the connecting rod 2 in which the release preventing member 10 is inserted and connected. In addition, the fall prevention member 10 of this embodiment is a shape which has the function as a rotation control member which prevents the relative rotation of the connecting rod 2 and the piston 4, and is not the connecting rod 2 side, but the piston 4 It is one of the features that is fixed to the side.

In installing the rotation restricting member, a method of fixing to the piston 4 side and a method of fixing to the connecting rod 2 side as in the present embodiment is conceivable, but in this embodiment, a method of fixing to the piston 4 side as described above. Was adopted. In the operating state of the hermetic compressor, the rotational motion of the crankshaft 7 is converted into the reciprocating motion of the piston 4 via the connecting rod 2 to compress the refrigerant in the cylinder 1. That is, in the reciprocating compressor, the piston 4 performs the reciprocating motion, while the connecting rod 2 performs the complex motion in the direction of the reciprocating motion of the piston 4 and the direction orthogonal thereto. Therefore, in the case where the rotation restricting member is provided on the piston 4 side, as compared with the case in which the rotation restricting member is provided on the connecting rod 2 side, the fixing is less likely to fall and the reliability can be improved.

In addition, during one cycle in which the piston 4 reciprocates, the relative positional relationship between the piston 4 and the connecting rod 2 is always changed. Here, when the rotation restricting member is provided toward the connecting rod 2 side, the rotation restricting member is always changed in position within the opening of the piston 4, and it is easy to cause an increase in the sliding surface. Since the increase of the sliding surface can be a cause of a joint sound, there existed a problem that it was easy to bring about the fall of quality with reliability. In this embodiment, the rotation restricting member is provided on the piston 4 side, and this problem is solved.

As shown in Fig. 6, the release preventing member (or rotation control member, hereinafter equivalent) 10 of the present embodiment includes a first elastic portion 10a, a second elastic portion 10b, and a support portion connecting both elastic portions. It is comprised by providing the rotation control part 10d which regulates the relative rotation of 10c and the connecting rod 2. As shown in FIG. In each of these structures, the 1st elastic part 10a and the 2nd elastic part 10b contact the inner peripheral part inside the opening of the piston 4, and the fall prevention member 10 is supported by elastic force. The state which the fall prevention member 10 was able to install in the piston 4 with the connecting rod 2 is mentioned later.

The rotation limiting portion 10d forms a wall for restricting the connecting rod 2 and the piston 4 when they are to be relatively rotated, and these walls are provided to face each other. In the state in which the connecting rod 2 was provided, the planar portion provided in the concrete portion 2a of the connecting rod 2 and the respective rotation restricting portions 10d are disposed to face each other. In this embodiment, since the dimension part smaller than the opening dimension L of the durable surface 4a provided in the concrete part 2a is formed by the flat part, the part which becomes substantially planar to the rotation restricting part 10d is provided. In addition, both rotation restricting portions 10d facing each other are provided so as to be substantially parallel to each other. The shape of the rotation restricting portion 10d will be described later.

Fig. 7 is a perspective view showing a state in which this release preventing member 10 can be provided. If the fall prevention member 10 can be provided, the 1st elastic part 10a will generate | occur | produce the force which presses the inner peripheral part 4b of the piston 4, and the fall prevention member 10 will be moved to the piston 4 by friction force. ) Inside the opening. Similarly, the second elastic portion is also brought into contact with the inner circumferential portion 4b so that the release preventing member 10 is firmly fixed inside the opening of the piston 4. Thus, both elastic parts 10a and 10b generate | occur | produce a force with respect to the rotation control part 10d in the direction which pinches the concrete part 2a.

With the fall preventing member 10 fixed in this way, even if the piston 4 rotates in the cylinder 1 and the connecting rod 2 and the piston 4 are to be relatively rotated, the connecting rod 2 is connected to the piston 4. It can be set as the structure which does not reach to the position which comes out from to. Because the distance between the rotation restricting portions 10d opposed to each other is smaller than the outer diameter of the spherical portion 2a, when the connecting rod 2 and the piston 4 are relatively rotated, the outside of the spherical portion 2a This is because the spherical surface always comes into contact with the rotation restricting portion 10d to restrict the rotation.

In addition, in this embodiment, since the rotation restricting portion 10d forming the wall is fixed by the first elastic portion 10a and the second elastic portion 10b, which are spring structures, the rotation restricting portion 10d and the connecting rod are fixed. Even when the concrete part 2a of (2) collides, excessive deformation of both can be prevented. In addition, even when the fall prevention member 10 is provided, the ball joint structure is realized without deforming the inner surface 4a of the piston 4 or the concrete portion 2a of the connecting rod 2.

In addition, since the rotation restricting portion 10d simply forms a wall, it does not slide with the connecting rod 2 in the general operating state of the compressor. Therefore, it is possible to suppress the loss and the occurrence of noise caused by the friction of both.

Or since the spring member which comprises the elastic part 10a, 10b is arrange | positioned in the circumferential direction of the inner peripheral surface of a piston, it is not only possible to stably hold | maintain the installation state of the rotation control part 10d, Easily providing the fall prevention member 10 is also improved. In addition, since the elastic portions 10a and 10b have a curved shape along the inner circumferential surface 4b of the piston 4, new stable holding of the rotation restricting portion 10d is possible.

Moreover, between the elastic part 10a and rotation control part 10d which are located upward, and the elastic part 10b and rotation control part 10d which are located below, are connected by the support part 10c, and this elasticity Since the part 10a, 10b, the rotation restricting part 10d, and the support part 10c are comprised by one member, the holding | maintenance of an installation state and the easy installation can be improved.

8 (a) and 8 (b) show a state in which the concrete portion 2a of the connecting rod 2 is in contact with the rotation restricting portion 10d, and FIG. 8 (a) shows a contact state. 8B is a perspective view at the time of contact. When the connecting rod 2 and the piston 4 rotate relatively, the spherical portion 2a is in contact with the rotation restricting portion 10d. At this time, the piston 4 is prevented from falling from the connecting rod 2 by restricting the excessive rotation of the rotation regulating portion 10d as a wall. In addition, since the rotation restricting portion 10d is elastically supported by the elastic portions 10a and 10b, the spherical portion 2a rotates even when the connecting rod 2 and the piston 4 rotate abruptly. When colliding with the restricting portion 10d, impact is reduced to prevent breakage.

As shown in Figs. 8A and 8B, the rotation restricting portion 10d of the present embodiment has a convex shape toward the concrete portion 2a side, and is located above the inner surface 4a of the piston 4. This convex-shaped part 10d 'enters into the opening part of a side. Moreover, the fall prevention member 10 is provided so that the opening of the lower side of the durable surface 4a may also enter a convex-shaped part like the upper side. The function of having such a rotation restricting portion 10d is as follows.

If there is no convex portion 10d 'as described above in the rotation restricting portion 10d, and the overall planar shape is formed, when the relative rotation between the piston 4 and the connecting rod 2 occurs, the rotation restricting portion 10d The first contact with) becomes the boundary portion 2a 'between the arc portion and the planar portion of the spherical portion 2a. Since this part corresponds to an arc and a planar ridge, sudden collision with the rotation restricting portion 10d may cause damage to the rotation restricting portion 10d or the boundary portion 2a '. In addition, when the rotation restricting portion 10d has a simple planar shape, there is a problem that deformation is likely to occur at the time of contact.

In this embodiment, the constitution has a convex portion 10d 'to solve such a problem. However, simply providing the convex portion 10d 'contributes to the strength improvement of the rotation restricting portion 10d. However, depending on the shape and the height, the boundary portion 2a' is first connected with the rotation restricting portion 10d. It crashes. Thereby, the convex portion 10d 'of the present embodiment is supposed to initially contact the planar portion of the concrete portion 2a at the time of relative rotation of the piston 4 and the connecting rod 2. As a specific structure, the width | variety of the planar part of the connecting rod concrete part 2a which opposes convex-shaped part 10d 'becomes larger than the width | variety of the upper end part of convex-shaped part 10d'.

In this way, by allowing the rotation restricting portion 10d to be in contact with the flat portion, which is the small dimension portion of the concrete portion 2a, a strong improvement as to the rotation restricting portion 10d and the entire fall prevention member 10 can be achieved. In addition, damage to the connecting rod 2 due to a collision or the like can be reduced.

In addition, as shown in FIG. 8, the convex portion 10d 'is not capable of blocking the space between the spherical portion 2a and the release preventing member 10, and provides a space therebetween to prevent inflow and outflow of lubricant oil. Clearing a gap for

In addition, in this structure, the 1st elastic part 10a and the 2nd elastic part 10b are connected by the support part 10c, and the distance between rotation control parts 10d and 10d is hold | maintained. Although the support part 10c connects the front of both rotation control parts mutually, there existed a case when a collision with the concrete part 2a on the side of the connecting rod 2 occurred. That is, when the rotational force in the axial direction of the piston 4 acts excessively, the concrete part 2a of the connecting rod 2 and the rotation restricting part 10d contact and collide, and the elastic parts 10a and 10b press-fit. As a result, a phenomenon may occur in which the insides of both rotation restricting portions 10d are opened.

At this time, since the relationship between the fall prevention member 10 and the connecting rod 2 as described above cannot all be held, the fall prevention member 10 is easily separated from the piston 4. Thereby, the fall prevention member 10 is fixed to the inside of the piston 4 in the form as shown below.

Fig. 9 is a cross sectional view of the connecting portion between the connecting rod 2 and the piston 4, and this cross section corresponds to the A-A cross section in Fig. 2 in a state where both are connected. 9, the shape of the fall prevention member 10 and the shape of the piston 4 are demonstrated. The fall prevention member 10 in this example is provided with the extending | stretching part 10e extended | stretched to the inner peripheral surface side of the piston 4 from the support part 10c. The edge part of the extending | stretching part 10e is formed to bend to the opening side of the piston 4, and the direction of this bending should just be opposite to the elastic part 10a, 10b. That is, with respect to the elastic parts 10a and 10b located in the inside of the piston 4 from the support part 10c, the edge part of the extending | stretching part 10e can be bent to the opening side of the piston 4. The bend shape is not particularly limited as long as the bending shape satisfies the above conditions and the end portion of the elongated portion 10e is inserted into the groove 4c provided on the inner circumferential surface of the piston 4.

In the state where the end of the extending portion 10e is inserted into the groove 4c, the tip of the extending portion 10e is in contact with the stepped portion of the groove 4c, so that the bent shape of the stretching portion 10e and The distal end of the elongated portion 10e is supported from the relationship in the direction in which the release preventing member 10 is pulled out, and the dropping from the piston 4 can be prevented. On the other hand, when providing the fall prevention member 10, when the edge part of the extending | stretching part 10e is press-fitted to the position of the groove | channel 4c, both can be combined easily and installation property can also be made favorable. Therefore, even when a force acts in the direction in which the fall prevention member 10 is disengaged from the piston 4, it can be restrained and it can prevent that the connection of the piston 4 and the connecting rod 2 falls.

10 is a perspective view of the release preventing member 10 in which the stretching portion 10e is provided in the supporting portion 10c. As shown in the figure, the stretching portion 10e is provided at exactly the intermediate position of both the rotation restricting portions 10d. The stretching portion 10e also has elastic force like the elastic portions 10a and 10b, and in the state of being press-fitted into the opening of the piston 4 in the installation of the release preventing member 10, on the inner circumferential surface of the piston 4 Impart elasticity to the When the stretching portion 10e is bent and press-fitted to the groove 4c position, the distal end portion of the stretching portion 10e is inserted into the groove 4c.

In the state where the distal end portion of the stretching portion 10e is inserted into the groove 4c and the release preventing member 10 can be installed in the piston 4, the stretching portion 10e is located within the groove 4c. It is not necessary to give elastic force to the inner circumferential surface. However, in this embodiment, even if the fall prevention member 10 can be provided, it is provided so that an elastic force may be provided to the inner peripheral surface of the piston 4. By providing the fall prevention member 10 in this way, the fall prevention member 10 can be prevented from falling off from the piston 4 effectively.

Although the above-mentioned example showed that the extending | stretching part 10e was provided in the support part 10c, and the edge part of the extending | stretching part 10e couple | engages with the groove | channel 4c, FIG. 10 shows the piston in the elastic part 10a, 10b. The example provided with the extending | stretching part 10e extended to the inner peripheral surface side of (4) is shown. FIG. 11 is a longitudinal cross-sectional view of the connecting portion of the connecting rod 2 and the piston 4 in the present example, and this cross section corresponds to the B-B cross section of FIG. 2 in a state in which both are connected.

In this example, since the end portion of the stretching portion 10e is inserted into the groove 4c, the stretching portion 10e and the groove (even when a force is applied in the direction in which the release preventing member 10 is removed from the piston 4). 4c) couple | bonds, and the edge part of the extending | stretching part 10e is supported, and it can suppress that the fall prevention member 10 falls out of the piston 4. As shown in FIG. Therefore, the connection state of the connecting rod 2 and the piston 4 is hold | maintained, and it can be set as the structure which contributes to ensuring reliability.

In addition, in the example of FIG. 11, since the extending | stretching part 10e is provided in elastic part 10a, 10b, the following effects are exhibited. In the present example, since the first elastic portion 10a and the second elastic portion 10b are disposed at positions facing the concrete portion 2a of the connecting rod 2 and the rotation restricting portion 10d, the piston 4 Sphere part 2a, rotation control part 10d, 1st elastic part 10a (or 2nd elastic part 10b), extending | stretching part 10e, a groove toward the outer side of the piston 4 from the inside center side. It is located in order of (4c). Therefore, even if the concrete part 2a collides with the rotation control part 10d, the force in the direction in which the coupling | bonding part 10e and the groove | channel 4c fall is hard to act, and the fall prevention member 10 is hard to fall off. It can be done.

Hereinafter, the result of having examined about the effect of this structure is mentioned, showing another example of such an Example. Here, the case where the radius of the concrete part 2a of the ball joint structure is 6.495 mm and the radius of the durable surface 4a is 6.505 mm is demonstrated as an example. In addition, in the ball joint structure, the diameter of the spherical portion 2a is smaller than the diameter of the inner surface 4a on the piston 4 side, and lubricating oil flows in and out of the gap portion caused by the difference in diameter. Lubrication is performed between both members. In addition, since the center positions of both are not always present at the same position, in particular, a recess is provided in the innermost part of the piston 4 (see FIGS. 9, 11 and the like). This recessed part also functions as an oil storage part of lubricating oil, for example, may be a structure which communicates with a recessed part by providing the supply hole of lubricating oil in the connecting rod 2, as shown in FIG.

In addition, as angle of the durable surface 4a in the cross section shown in FIG. 3, angle θ41 from the shaft center of the piston 4 was 97 °, and angle θ42 shown in FIG. 4 was 34 °. By defining θ41 and θ42 as described above, the path through which the lubricating oil in the BB cross section passes is shortened by about 1/3 compared with the AA cross section, and the ball is compared with the case where the durable surface 4a is 97 ° over the entire surface. The flow rate of the lubricating oil flowing through the joint structure was increased by about three times.

Moreover, the groove | channel 4c provided in the inner peripheral surface of the piston 4 was made into the rectangle of width 1mm and depth 1mm, and was uniformly provided in the ring-shaped inner periphery of the piston 4.

When the ball joint structure having such a specific structure was used in the hermetic compressor, the result was that the ball joint structure can be maintained without satisfactory sliding mobility. This result is the same as the fall prevention member as shown in Figs. 9 and 10 and the fall prevention member as shown in Fig. 11, and it is understood that having each of the above structures contributes to the improvement of the efficiency and reliability of the compressor. I could confirm it.

As described above, according to each embodiment of the present invention, the assembly can be performed easily without deforming the inner and outer surfaces of the ball joint structure. In addition, by cutting off a portion of the inner side and the outer side of the ball joint mechanism part, the sliding area is reduced and the movement of the lubricating oil is facilitated.

Therefore, the sliding loss at the time of operation of the hermetic compressor can be reduced, contributing to the improvement of the efficiency, and the noise caused by the occurrence of the noise can be suppressed.

In addition, since the disconnection of the ball joint structure can be suppressed, a hermetic compressor having high reliability can be provided.

Next, the material of the piston 4 and the connecting rod 2 which comprise the ball joint mechanism part is demonstrated. In this embodiment, the spherical portion 2a serving as the sliding portion of the ball joint and the inner surface 4a of the piston 4 are made of an iron-based sintered material sealed by an oxide film. Specifically, after sintering the raw material powder, the shape is appropriately processed, and the water vapor treatment is performed to seal the inside and the surface of the pores with an oxide film formed on the surface of the pores, and the lubricating oil film is easily discharged through the pores. I do not want to. As will be described later, the oxide of the sealing portion by the steam treatment also has the effect of improving the strength of the sintered material.

12 shows the results of the sliding test performed by the ring-on block friction tester on the material used for the piston 4 and the connecting rod 2. In this test, the sliding speed was 1.01 m / s and the test load was 123.5 N. The sintered material 1 and the sintered material 2 are used for a sliding test, and each of these sintered materials differs in carbon content (refer to * of FIG. 12). The combination of the rotating piece and the stationary piece included an oxide film treatment with water vapor and also one subjected to nitriding treatment. As a combination of the rotating piece and the stationary piece, tests were carried out for each knitting of Nos. 1 to 5 to measure the amount of wear.

From the test results shown in the drawings, it can be seen that in the numbers 1 and 2 using the sintered material in which only the fixed piece was subjected to the oxide film treatment, the wear amount of the rotating piece was large. On the other hand, the numbers 3, 4, and 5 using the sintered material in which both the rotating piece and the fixed piece were subjected to the oxide film treatment resulted in less wear. As a result, it can be said that the amount of wear can be reduced by using the sintered material sealed by the steam for the piston 4 and the connecting rod 2.

Fig. 13 shows the results of Rockwell B scale appearance hardness measurement of the sintered material. Contrary to the knitting of the material with less wear in Fig. 12, it is found that the hardness of the rotating piece is a knitting equal or about 10 higher on the Rockwell B scale than the hardness of the fixed piece. According to such knitting, the wear amount of the connecting rod 2 which is likely to cause a problem due to wear can be reduced.

As a result of these Figs. 12 and 13, it is assumed that the material of the piston 4 and the connecting rod 2 is subjected to an oxide film treatment to the sintered material.

As a concrete example, the Fe-Cu-C sintered material subjected to the oxide film treatment is used as the material of the piston 4, and the Fe-Cu-C sintered material subjected to the oxide film treatment is used as the material of the connecting rod 2. By using the piston 4 and the connecting rod 2, a hermetic compressor as shown in Fig. 1 was produced. When the operating speed of this hermetic compressor was operated at 4900 revolutions per minute for 30 days at a discharge pressure of 1.6 MPa, abnormal wear did not occur in the ball joint structure, and a result was obtained in which good sliding mobility could be maintained.

As a second example, the Fe-Cu-C sintered material subjected to the oxide film treatment and the nitriding treatment was used as the material of the connecting rod 2, and the Fe-Cu-C sintered material subjected to the oxide film treatment was used as the material of the piston 4. When the sealed compressor was manufactured and operated for 30 days at 4900 revolutions per minute and discharge pressure of 1.6 MPa for 30 days, no abnormal wear occurred in the ball joint structure, and the result was able to maintain good sliding mobility. .

As a third example, a Fe-Cu-C-based sintered material which has been subjected to an oxide film treatment and nitriding treatment as the material of the piston 4, and Fe-Cu-C which has been subjected to an oxide film treatment and nitriding treatment as the material of the connecting rod 2 is used. A sealed compressor using a sintered material was manufactured and operated for 30 days at an operating speed of 4900 revolutions per minute and a discharge pressure of 1.6 MPa for 30 days. Even in this case, abnormal wear does not occur in the ball joint structure, and retains good sliding mobility. The result was possible.

As regards these three examples, the following considerations are given. 14 is a measurement result showing the relationship between the depth and the hardness of the piston material and the connecting rod material. As shown in the figure, the depth from the surface of each material is taken as the horizontal axis, and the Vickers hardness (HV) is used as the vertical axis, and the relationship between the depth of the material and the hardness is shown. As an example of (A) of the sintering material 1, the thing which carried out the nitriding process about the thing sealed by the oxide film which forms the empty hole in the inside and the surface by the steam process after sintering on the surface of the empty hole is used. The example (B) shows that the nitriding treatment was performed without performing the oxide film treatment, and the example (C) shows an example where the oxide film treatment was performed and the nitriding treatment was not performed.

In addition, the example ((alpha)) of the sintered material 2 performed the oxide film process and the nitriding process, and the example ((beta)) shows the example which performs an oxide film process and does not perform nitriding process. This nitriding treatment was carried out by general gas soft nitriding at a nitriding treatment temperature of about 500 to 600 占 폚.

As can be seen from Fig. 14, when the oxide film is formed by the steam treatment, further nitriding treatment improves the hardness. Therefore, it is preferable to use the sintered material by which the connecting rod 2 was sealed by water vapor | steam and further nitriding was performed. At this time, the sintered material subjected to nitriding treatment may also be used for the piston 4 (third example above), but the surfaces of the piston 4 may be avoided from being of the same grade, and the piston 4 may not be subjected to nitriding treatment ( Second example above).

On the other hand, in the case where nitriding treatment is performed without performing the sealing treatment with water vapor, as shown in Fig. 14, the inside of the sintered material is hardened to the inside and embrittled as a whole material. Therefore, it is easy to cause the fall of reliability by breakage of the connecting rod 2, etc.

In this embodiment, the portion close to the surface retains sufficient hardness to ensure wear resistance, while the internal hardness is lower than the portion close to the surface with Vickers hardness, thereby obtaining a connecting rod 2 having excellent toughness. Therefore, nitriding treatment is performed after the sealing treatment is performed by steam treatment, whereby it becomes possible to provide a hermetic compressor having excellent reliability.

In addition, the same effect can be expected even if a carburizing process or a immersion nitriding process is performed instead of said nitriding process.

In order to perform the above-mentioned surface treatment, manufacture needs to consider the following dimensions. That is, in manufacture of the connecting rod 2, a shape is first processed suitably after sintering of a raw material powder. At this time, it is necessary to make the diameter of the part used as the concrete part 2a of the connecting rod 2 smaller than the diameter of the inner surface 4a of the piston 4 at the time of completion. On the contrary, the diameter of the part which becomes the durable surface 4a of the piston 4 needs to be made larger than the diameter of the concrete part 2a of the connecting rod 2 at the time of completion. Thereafter, steam treatment or the like is performed, and the diameter of the spherical portion 2a becomes larger and the diameter of the durable surface 4a becomes smaller.

Next, the fall prevention member 10 is demonstrated. The connecting rod 2 can further improve reliability by making surface hardness smaller than the fall prevention member 10. As shown in Fig. 8, the portion where the concrete portion 2a of the connecting rod 2 comes into contact with the release preventing member 10 is a flat portion provided in the concrete portion 2a. It is not a part which slides with the inner surface 4a of the piston 4. Therefore, even if the flat part is worn by a slight amount, for example, there is no big change in the sliding relationship with the piston 4.

On the other hand, when the fall prevention member 10 is worn by the contact with the concrete part 2a, and the thickness of the rotation control part 10d becomes thin, the fall prevention member 10 will be damaged, and the piston 4 and the connecting rod 2 will be damaged. ) May be disconnected. At this time, the function as a hermetic compressor is impaired, which causes a failure. In this embodiment, the fall prevention member 10 aims at the improvement of reliability by using SUS301-1 / 4H which has hardness higher than the surface hardness of the connecting rod 2. As shown in FIG.

As mentioned above, when the hermetic compressor of the present embodiment described above is actually operated, care must be taken so that the temperature of the sliding portion does not become too high. This is because an excessive increase in the temperature of the sliding part leads to the promotion of abrasion, and consequently a decrease in reliability. In particular, in the present embodiment using the surface-treated sintered material, the temperature of the sliding portion during operation is set to 150 ° C. or lower in order to prevent a decrease in reliability due to excessive rise in temperature. As a result of the same test as those of the first to third examples described above, when the temperature of the sliding portion is set to 150 ° C. or lower, abnormal wear does not occur in the ball joint structure, and it is possible to retain good sliding mobility. Achieveable results were obtained.

Moreover, the lubricating oil used at the time of actual operation is demonstrated. As in the above embodiment, in order to hold the oil film on the surface of the piston 4 and the connecting rod 2 using the sintered material subjected to the sealing treatment (oxidation film treatment) or the nitriding treatment with water vapor, the adsorption force is applied to the nitride film surface as lubricating oil. It is effective to use this good ester synthetic oil. The sealing treatment is essential for retaining the oil film of the lubricating oil supplied to the sliding part, and by using the ester synthetic oil having good compatibility with the nitride film, not only the sliding loss can be reduced but also abnormal wear can be suppressed.

As an example, when hydrocarbon based R600a (isobutane) is used as the refrigerant and ester synthetic oil is used as the lubricating oil, abnormal wear does not occur in the ball joint structure, resulting in good sliding mobility. Got it. Moreover, even if it used and mixed mineral oil and ester type synthetic oil as lubricating oil, favorable sliding mobility was maintained, and high reliability was acquired compared with the case where only mineral oil was used as lubricating oil.

According to the embodiment described above, since abnormal wear occurring on the inner and outer surfaces of the ball joint structure can be suppressed, long-term reliability of the hermetic compressor is ensured. In addition, the sliding loss during the operation of the hermetic compressor can be reduced, thereby contributing to the improvement of the efficiency of the hermetic compressor. Therefore, it becomes possible to provide the hermetic compressor which is highly reliable and suitable for electric power saving.

1 is a longitudinal sectional view of a hermetic compressor according to one embodiment of the present invention;

Figure 2 is a detailed view of the inner structure of the piston.

3 is a sectional view taken along the line A-A of FIG.

4 is a cross-sectional view taken along line B-B in FIG.

5 is a perspective view of the connecting rod.

6 is a perspective view of the release preventing member.

7 is a perspective view showing an assembled state of a piston and a connecting rod;

8 (a) and 8 (b) show a state in which the concrete portion of the connecting rod is in contact with the rotation restricting portion.

9 is a cross sectional view of a connecting portion of the connecting rod and the piston;

Fig. 10 is a perspective view of the release preventing member provided with the stretching portion in the support portion;

11 is a longitudinal sectional view of a connecting portion of a connecting rod and a piston;

12 is a wear test result of the piston material and connecting rod material.

Figure 13 shows the hardness measurement results of the piston material and connecting rod material.

14 is a measurement result showing the relationship between depth and hardness of piston material and connecting rod material.

<Explanation of symbols for the main parts of the drawings>

1: cylinder

2: connecting rod

2a: sphere

2a ': boundary

4: piston

4a: Durable surface of piston

4c: home

7: crankshaft

10: fall prevention member

10a: first elastic portion

10b: second elastic portion

10c: support

10d: rotation control unit

10d ': convex shape

10e: drawing part

Claims (5)

In a hermetic compressor in which a compression mechanism and an electric motor are housed in a hermetic container, and a crankshaft and a piston driven by the electric motor are connected in a ball joint structure by a connecting rod. The ball joint structure is composed of a durable portion provided on the piston, and a concrete portion provided on the connecting rod, The hermetic compressor and the spherical portion are hermetic compressors sealed with an oxide film. The hermetic compressor according to claim 1, wherein the concrete portion is an iron-based sintered material subjected to sealing treatment with an oxide film and nitriding treatment. 3. The hermetic compressor according to claim 2, wherein the durable surface is also a nitrided iron-based sintered material. The hermetic compressor according to any one of claims 1 to 3, wherein the connecting rod has a Vickers hardness, and an inner hardness thereof is lower than a portion close to the surface. The hermetic compressor according to any one of claims 1 to 3, wherein a hydrocarbon-based refrigerant is used as the refrigerant compressed by the compression mechanism and an ester synthetic oil is used as lubricating oil.

Images