JPH05209588A - Closed type compressor - Google Patents

Abstract

PURPOSE:To improve abrasion resistance and the reliability by preventing interference between a piston rod and a cylinder, the skirt part of a piston, a ball holding part, or the like in a reciprocating closed type compressor of such constitution as to decenter the axis of a crankshaft in relation to the centerline of the cylinder. CONSTITUTION:A compression element is formed of a cylinder 1 and a piston 2, and the axis O2 of a crankshaft 3 is decentered in relation to the center O1 of the cylinder to form a reciprocating closed type compressor with the intersecting angle of a piston rod 4 to the center O1 of the cylinder 1 being set small (alpha1) at the compression time and large (alpha2) at the suction time. Connection is then made in such disposition that the center C of the rod part 4a of the piston rod 4 in relation to the center B of the crankpin 5 of the crankshaft 3 is decentered in the opposite direction to the eccentric direction of the crankshaft 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating type hermetic compressor applied to a refrigerating cycle device or the like, and more particularly to a hermetic compressor having an improved piston rod or its connecting portion.

[0002]

2. Description of the Related Art Conventionally, as a reciprocating type hermetic compressor, for example, one having a structure shown in FIG. 9 is known. That is, the horizontal support frame 12 is provided in the closed case 11, the electric element 13 is supported on the lower portion of the support frame 12, and the compression element 14 is fixedly supported on the upper portion. The electric element 13 is configured to have a stator 13a and a rotor 13b, and an upper end side of the crankshaft 3 which is a vertical rotation shaft connected to the rotor 13b is supported by a bearing 15 provided on the support frame 12.

On the other hand, the compression element 14 is composed of a cylinder 1 and a piston 2. The piston 2 is connected to a crank pin 5 provided on the upper end of a crank shaft 3 via a piston rod 4. The cylinder 1 includes a valve mechanism 17, a discharge chamber 18, and a discharge muffler 1.
9 is provided.

The compression element 14 will now be described with reference to FIGS.
The mechanism and action of will be described in detail. As shown in FIG. 10, the axis O2 of the crankshaft 3 is eccentric with respect to the center O1 of the cylinder 1 by a predetermined distance e, and the crossing angle α1 of the piston rod 4 at the time of compression with respect to the cylinder center O1 is α1.
Is small and the crossing angle α2 at the time of suction is set large (hereinafter, e is referred to as an offset amount).

According to this structure, since the intersection angle α1 of the piston rod 4 at the time of compression with respect to the cylinder center O1 becomes small in the compression stroke where the load is large, the sliding surface between the cylinder 1 and the piston 2 is orthogonal. The component force in the direction is reduced, and wear resistance between the cylinder 1 and the piston 2 is improved, and thus reliability is improved.

In the conventional structure shown in the same figure, the piston rod 4 is formed in a straight rod shape, and the center C of the rod portion 4a and the center B of the crank pin 5 of the crankshaft 4 coincide with each other.

The piston rod 4 is connected to the piston 2 via a ball joint 6, and the ball 7 is rotatably held by a ball-shell-shaped ball holding portion 8 projecting from the piston 2. The projecting length of the ball holding portion 8 is substantially uniform over the entire circumferential direction.

[0008]

In the above-mentioned conventional structure, the preferable offset amount e is determined by the distance 1 between the skirt portion 1a of the cylinder 1 and the crankshaft axis O2, the eccentric radius r of the crankpin 5, and the like. ..

For example, when an optimum offset amount e is to be obtained while l is constant, the eccentric radius r of the crank pin 5 is r.
May need to be increased.

In this case, in the above-mentioned conventional structure, the rod portion 4a of the piston rod 4 has a straight rod shape, and the rod portion 4a
The center C of the crankshaft 4 and the center B of the crankpin 5 of the crankshaft 4 are connected so as to coincide with each other.
1, the skirt portion 1a of the cylinder 1 and the piston rod 4 interfere with each other, and as shown in FIG.
In some cases, the gap g1 between the piston rod 4 and the skirt portion 2a of the piston 2 becomes small and a predetermined offset amount cannot be set.

Further, in the above-described construction having the ball joint 6, the projecting length of the ball holding portion 7 of the piston 2 is uniform over the entire circumferential direction, and for example, as shown in FIG. Since the left and right opening angles β1 and β2 for rod swing are the same, if an attempt is made to increase the offset amount under such a configuration, the crossing angle α2 in the eccentric direction of the crankshaft 3 will be large. Therefore, the gap g2 between the piston rod 4 and the ball holding portion 7 becomes small in this direction, and the predetermined offset amount may not be set in some cases.

Therefore, in the conventional compressor, the piston rod approaches or interferes with the cylinder or the skirt portion of the piston, or with the ball holding portion in the ball joint type, respectively. The offset amount may not be set.
This is especially likely to be a problem when a large stroke and offset amount are required, that is, when the wear resistance of a large compressor is improved.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a reciprocating type hermetic compressor having a structure in which the axis of a crankshaft is eccentric with respect to the center of a cylinder. The purpose is to prevent interference with the skirt portion of the cylinder or piston, the ball holding portion, or the like to improve wear resistance and thus reliability.

[0014]

In order to achieve the above-mentioned object, the invention of claim 1 forms a compression element by a cylinder and a piston, and makes the axial center of the crankshaft eccentric with respect to the center of the cylinder. Thus, in the reciprocating type hermetic compressor in which the crossing angle of the piston rod with respect to the center of the cylinder is small at the time of compression and large at the time of suction, the rod portion center of the piston rod is set to the crankpin center of the crankshaft, The crankshaft is eccentric in a direction opposite to the eccentric direction.

According to a second aspect of the present invention, a compression element is constituted by a cylinder and a piston, the axis of the crankshaft is eccentric with respect to the center of the cylinder, and the crossing angle of the piston rod with respect to the center of the cylinder is reduced during compression. In the reciprocating type hermetic compressor that is largely set at the time of suction, the rod portion of the piston rod has a curved rod shape in which a side surface in the same direction as the eccentric direction of the crankshaft is recessed.

According to a third aspect of the present invention, a compression element is constituted by a cylinder and a piston, and the piston rod is connected to the piston through a ball joint.
In a reciprocating hermetic compressor in which the axis of the crankshaft is eccentric with respect to the center of the cylinder, the opening angle for swinging the piston rod formed in the ball holding portion of the piston is set to It is characterized in that it is set to be large in the same direction as the eccentric direction and small in the opposite direction.

[0017]

According to the first aspect of the invention, since the center of the rod portion of the piston rod is connected to the crankpin center in a direction eccentric to the eccentric direction of the crankshaft, these centers coincide. Compared with the conventional structure, the distance until the piston rod interferes with the cylinder, the skirt portion of the piston, etc. on the eccentric side of the crankshaft can be lengthened by the amount of eccentricity of the center of the rod portion of the piston rod.

Therefore, according to the present invention, by preventing the interference of the piston rod, it becomes easier to obtain the optimum offset amount as compared with the conventional one, and the wear resistance and hence the reliability can be further improved.

According to the second aspect of the present invention, the rod portion of the piston rod has a curved rod shape in which the side surface in the same direction as the eccentric direction of the crankshaft is recessed, so that the piston rod has a straight rod shape as compared with the conventional structure. The distance until the piston rod interferes with the cylinder, the skirt of the piston, or the like can be lengthened by the recessed distance.

Therefore, according to the present invention, similarly to the first aspect of the present invention, the interference of the piston rod on the eccentric side of the crankshaft is prevented so that the optimum offset amount can be easily obtained, and the wear resistance and the reliability are improved as compared with the conventional case. It is possible to further improve the sex.

According to the invention of claim 3, in the structure having the ball joint type piston rod, the opening angle for swinging the piston rod formed in the ball holding portion of the piston is set in the same direction as the eccentric direction of the crankshaft. Since it is set to a large value and set to a small value in the opposite direction, compared to the conventional structure in which the opening angle of the ball holding part is uniform over the entire circumference, until the piston rod interferes with the ball holding part on the eccentric side of the crankshaft. The swing angle of can be increased.

Therefore, according to the present invention as well,
As in the invention of 2, the prevention of the piston rod interference
The optimum offset amount can be easily obtained, and the wear resistance and hence the reliability can be further improved as compared with the conventional case.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. Note that common symbols are used throughout the drawings to simplify the description.

1 to 3 show a first embodiment of the present invention. FIG. 1 is a sectional view showing a main part of a compression element portion, FIG. 2 is a diagram showing one configuration example of a piston rod, and FIG. 3 is a diagram showing another configuration example of a piston rod.

In the compressor of this embodiment, as shown in FIG. 1, the compression element is constituted by the cylinder 1 and the piston 2, and the axial center O2 of the crankshaft 3 with respect to the center O1 of the cylinder 1 has a constant offset amount. It is eccentrically arranged with e. As a result, the crossing angle α1 of the piston rod 4 with respect to the cylinder center O1 at the time of compression is set to be small, and the crossing angle α2 at the time of suction is set to be large.

In the present embodiment, the rod portion 4a of the piston rod 4 is formed in a straight rod shape, the large end portion 4b is formed in a ring shape, and the small end portion is formed as a ball 7 constituting the ball joint 6. .. The center C of the rod portion 4a of the piston rod 4 is eccentric with respect to the center B of the crank pin 5 in the direction opposite to the eccentric direction of the crankshaft 3 (rightward in the figure) (leftward in the figure). Has been done.

For example, in the example of FIGS. 1 and 2, the structure is such that the rod portion 4a of the piston rod 4 is joined to the large end portion 4b along the tangent line of the large end portion 4b with the eccentricity a1. There is.

In the example of FIG. 3, the rod portion 4a of the piston rod 4 is joined to the large end portion 4b at an oblique position deviated from the center of the large end portion 4b with an eccentric amount a2. There is.

The ball 7, which is the small end portion of the piston rod 4, is rotatably held by a ball shell-shaped ball holding portion 8 provided on the piston 2.

According to the configuration of this embodiment, the center C of the rod portion 4a of the piston rod 4 is eccentric with respect to the center B of the crank pin 5 in the direction opposite to the eccentric direction of the crank shaft 3. Compared with the conventional structure in which the centers coincide, the piston rod 4 is provided on the eccentric side of the crankshaft 3.
Eccentricity a1 of the piston rod 4 is the distance until the piston 1 interferes with the skirt portions 1a, 2a of the cylinder 1 and the piston 2.
It can be lengthened by a2. Therefore, the optimum offset amount e can be easily obtained as compared with the conventional structure, and the wear resistance and thus the reliability can be further improved.

FIG. 4 is a sectional view of the essential portions showing the second embodiment of the present invention.

In this embodiment, the rod portion 4a of the piston rod 4 has a substantially V-shaped curved rod shape in which the side surface in the same direction as the eccentric direction of the crankshaft 3 (right direction in FIG. 4) is recessed. There is.

As a result, the center c2 of the small end side portion of the piston rod 4 is folded to the center c1 connecting the large end 4a and the small end 4b when the piston rod 4 operates at the swing angle γ1. The crankshaft 3 oscillates while being rotationally displaced in the direction opposite to the eccentric direction of the crankshaft 3 (leftward in the figure) by an angle γ 2 due to the bend.

Therefore, for example, in the conventional structure using a linear piston rod, the piston rod is c
Since it swings at the position 1, the gap g with respect to the skirt portion 2a is small, whereas according to the present embodiment, the gap g is enlarged by the deviation of the angle γ2 due to the bending rod. As a result, the distance until the piston rod 4 and the skirt portion 2a interfere with each other becomes long.

Therefore, according to this embodiment, as in the case of the first embodiment, the crankshaft 3 is compared with the conventional structure.
It becomes easy to obtain an optimum offset amount for the above, and wear resistance, and thus reliability can be further improved.

The rod portion 4a of the piston rod 4 is not limited to the substantially doglegged shape shown in the figure, but can be variously modified as long as the side surface in the same direction as the eccentric direction of the crankshaft 3 is recessed.

5 to 7 show a third embodiment of the present invention. FIG. 5 is a cross-sectional view of an essential part showing a ball joint portion, FIG. 6 is a diagram showing one configuration example of the ball holding portion, and FIG. 7 is a diagram showing another configuration example of the ball holding portion.

In the present embodiment, as shown in FIG. 5, the opening angle of the opening 9 for swinging the piston rod formed in the ball holding portion 8 of the piston 2 is such that the crankshaft 3 has an opening angle of O 3 with respect to the opening center O 3. Larger in the same direction as the eccentric direction (θ1
), Small in the opposite direction (θ2), respectively.

That is, as shown in FIG. 6, the projecting length of the ball holding portion 8 is small in the same direction as the eccentric direction of the crankshaft (d1) and large in the opposite direction (d2),
Each is set.

In the example of FIG. 6, the opening 9 has a spherical shell.
The ball holding portion 8 is formed in a state of being opened by one cutting surface, and the opening center O3 which is the center of the cutting surface is inclined with respect to the piston center O4.

In the example of FIG. 7, the center O3 of the opening coincides with the center O4 of the piston.
The auxiliary opening 9a is formed so that the opening angle .theta.1 increases in the same direction as the eccentric direction.

According to this embodiment, the opening angle for swinging the piston rod 4 formed in the ball holding portion 8 of the piston 2 is large in the same direction as the eccentric direction of the crankshaft 3 and small in the opposite direction. Since the setting is made, the swing angle until the piston rod 4 interferes with the ball holding portion 8 on the eccentric side of the crankshaft 3 as compared with the conventional structure in which the opening angle of the ball holding portion 8 is uniform over the entire circumference. Can be increased. Therefore, as in the first and second embodiments, the prevention of interference of the piston rod 4 makes it easier to obtain an optimum offset amount, and further improves wear resistance and thus reliability as compared with the conventional one. become.

FIG. 8 is a graph showing the effect that the offset amount can be enlarged and set in the optimum range by the above embodiment, and the vertical axis shows the PV value and the horizontal axis shows the offset amount.

As shown by curve A in the figure, the PV value is initially
It decreases as the offset amount increases, but increases when it exceeds a certain value. In order to secure reliability, a PV value equal to or less than a certain value p is required (the range of the hatched D is desirable).

On the other hand, in the conventional construction, the offset value e0 is limited due to the restriction of the piston rod interference as described above, and therefore the PV value may deviate from the desired range. For example, the offset amount can be set large so that the PV value falls within the range of the diagonal line D.

[0046]

As described above, according to the present invention, in the hermetic compressor of the reciprocating type in which the axial center of the crankshaft is eccentric with respect to the center of the cylinder, the piston rod and the skirt portion of the cylinder or piston are provided. Alternatively, there is an excellent effect that interference with the ball holding portion or the like is prevented, and wear resistance and thus reliability are improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration example of a piston rod according to the embodiment.

FIG. 3 is a diagram showing another configuration example of the piston rod according to the embodiment.

FIG. 4 is a cross-sectional view of a main part showing a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of essential parts showing a third embodiment of the present invention.

FIG. 6 is a diagram showing a configuration example of a ball holder according to the embodiment.

FIG. 7 is a diagram showing another configuration example of the ball holder according to the embodiment.

FIG. 8 is a graph showing the function and effect of the embodiment.

FIG. 9 is a sectional view showing the overall configuration of a hermetic compressor.

FIG. 10 is a diagram showing a main part of a conventional configuration.

FIG. 11 is an explanatory view of the operation of the conventional configuration.

FIG. 12 is an explanatory view of the operation of the conventional configuration.

FIG. 13 is an explanatory view of the operation of the conventional configuration.

[Explanation of symbols]

 1 Cylinder 2 Piston 3 Crankshaft 4 Piston rod 4a Rod part 5 Crankpin 6 Ball joint 7 Ball 8 Ball holding part O1 Center of cylinder O2 Crankshaft axis α1, α2 Crossing angle θ1, θ2 Opening angle

Front page continuation (72) Inventor Hideyuki Shinagawa 70 Yanagimachi, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Yanagimachi factory

Claims (3)

[Claims] 1. A compression element is constituted by a cylinder and a piston, and an axial center of a crankshaft is eccentric with respect to the center of the cylinder, whereby a crossing angle of a piston rod with respect to the center of the cylinder is small at the time of compression and at the time of suction. In a reciprocating type hermetic compressor that is set large, the rod center of the piston rod is
A hermetic compressor characterized by being eccentric to a center of a crankpin of the crankshaft in a direction opposite to an eccentric direction of the crankshaft. 2. A compression element is constituted by a cylinder and a piston, the axis of the crankshaft is eccentric with respect to the center of the cylinder, and the intersecting angle of the piston rod with respect to the center of the cylinder is set small during compression and set large during suction. In the reciprocating type hermetic compressor,
A hermetic compressor, wherein a rod portion of the piston rod has a curved rod shape having a concave side surface in the same direction as the eccentric direction of the crankshaft. 3. A reciprocal type hermetic seal in which a compression element is constituted by a cylinder and a piston, a piston rod is connected to the piston via a ball joint, and the axis of a crankshaft is eccentric with respect to the center of the cylinder. In the mold compressor, the opening angle for swinging the piston rod formed in the ball holding portion of the piston is set to be large in the same direction as the eccentric direction of the crankshaft and small in the opposite direction. Hermetic compressor.