JP7064562B2 - Sealed refrigerant compressor and freezing / refrigerating equipment using it - Google Patents

Description

The present invention relates to a closed-type refrigerant compressor used in a refrigerator, an air conditioner, etc., and a freezing / refrigerating apparatus using the same.

In recent years, from the viewpoint of protecting the global environment, the development of a highly efficient closed-type refrigerant compressor that reduces the use of fossil fuels has been promoted. For example, in order to improve efficiency, it has been proposed to form various coatings on the sliding surface of a sliding member included in a closed-type refrigerant compressor and to use a lubricating oil having a lower viscosity.

In the closed type refrigerant compressor, the lubricating oil is stored in the closed container, and the electric element and the compression element are housed. The compression element includes, for example, a crankshaft, a piston, a connecting rod of a connecting means, and the like as a sliding member, and the main shaft and main bearing of the crankshaft, the piston and the bore, the piston pin and the connecting rod, and the eccentric shaft and the connecting rod of the crankshaft. Etc. all form sliding portions with each other.

For example, in Patent Document 1, in a reciprocating compressor (sealed refrigerant compressor) using a low-viscosity lubricating oil, the piston and connecting rod of the sliding members are made of an iron-based sintered material, and then steam is used. It is disclosed that the surface of the piston is treated and the steam layer is removed by cutting, and the connecting rod is subjected to the nitriding treatment after the steam treatment. Examples of the lubricating oil used in the reciprocating compressor having this configuration include those having a viscosity in the range of 3 mm ² / S to 10 mm ² / S at a kinematic viscosity of 40 ° C.

If the lubricating oil has a low viscosity, it becomes difficult to form an oil film, but in the closed-type refrigerant compressor disclosed in Patent Document 1, a special treatment is applied to the surface of the sliding member constituting the sliding portion. There is. This prevents wear or seizure on the piston and connecting rod even if a low-viscosity lubricating oil is used.

Japanese Patent No. 2011-021530

By the way, the crankshaft included in the closed-type refrigerant compressor constitutes a shaft portion of a compression element driven by an electric element, and this shaft portion is rotatably supported by a bearing portion. Here, although it is possible to further improve efficiency by reducing the sliding area of the shaft portion and the bearing portion (shaft support portion), the reduction of the sliding area lowers the wear resistance.

The reciprocating compressor (sealed refrigerant compressor) disclosed in Patent Document 1 described above uses a low-viscosity lubricating oil in the range of 3 mm ² / S to 10 mm ² / S at a kinematic viscosity of 40 ° C. The targets for improving wear resistance are pistons and connecting rods, and the shaft support parts are slid to improve efficiency as in the case of crankshafts, instead of the structure in which bearings are used to support the shafts as in crankshafts. It does not reduce the area.

The present invention has been made to solve such a problem, and it is possible to improve the reliability of the shaft portion pivotally supported by the bearing portion even if a lubricating oil having a lower viscosity is used. It is an object of the present invention to provide a possible closed type refrigerant compressor.

In order to solve the above-mentioned problems, the closed type refrigerant compressor according to the present invention stores lubricating oil having a kinematic viscosity at 40 ° C. of 1 mm ² / S to 9 mm ² / S in a closed container and is electrically operated. It houses an element and a compression element driven by the electric element to compress the refrigerant, and the compression element has a spindle as a shaft, a crank shaft having a spindle and an eccentric shaft, and a bearing that supports the shaft. A main bearing that supports the shaft and an eccentric bearing that supports the eccentric shaft are provided, and the sliding surface of the main shaft with the main bearing is divided into a single surface or a plurality of surfaces, and the sliding surface is described. When the surface is a single surface, when the axial length of the sliding surface is a single sliding length L, or when the sliding surface is divided into a plurality of surfaces, When the axial length of the sliding surface having the minimum axial length is a single sliding length L, the ratio L / of the single sliding length L to the outer diameter D of the main shaft. D is 0.51 or less, and the lubricating oil further contains sulfur or a compound having sulfur as a slidability modifier.

According to the above configuration, the lubricating oil has a low viscosity, and the ratio L / of the single sliding length L to the outer diameter D regardless of whether the sliding surface of the main shaft is a single surface or a plurality of surfaces. D is 0.51 or less, and the lubricating oil contains a sulfur-based slidable modifier. As a result, even if the viscosity of the lubricating oil is reduced and the sliding area is reduced so that the ratio L / D is 0.51 or less, the sulfur-based slidability modifier is good in the sliding portion. Abrasion resistance can be realized. As a result, it is possible to obtain a closed-type refrigerant compressor capable of improving the reliability of the shaft portion pivotally supported by the bearing portion even if a lubricating oil having a lower viscosity is used.

Further, the refrigerating / refrigerating apparatus according to the present invention includes a closed-type refrigerant compressor, a radiator, a decompression device, and a heat absorber having the above-described configuration, and includes a refrigerant circuit in which these are connected in a ring shape by a pipe. be.

According to the above configuration, the closed-type refrigerant compressor uses a low-viscosity lubricating oil to reduce the sliding area, and has good shaft reliability. By providing the freezing / refrigerating apparatus with a closed-type refrigerant compressor having such high efficiency and good reliability, its power consumption can be reduced and its reliability can be made high.

The above objectives, other objectives, features, and advantages of the present invention will be evident from the detailed description of the preferred embodiments below, with reference to the accompanying drawings.

INDUSTRIAL APPLICABILITY With the above configuration, the present invention provides a closed-type refrigerant compressor capable of improving the reliability of the shaft portion pivotally supported by the bearing portion even if a lubricating oil having a lower viscosity is used. It has the effect of being able to do it.

It is a schematic sectional drawing which shows an example of the structure of the refrigerant compressor which concerns on embodiment of this disclosure. It is a schematic side view which shows an example of the structure of the crankshaft provided in the refrigerant compressor shown in FIG. 1. 3A is a schematic view showing an example of a configuration in which the sliding surface is a single surface in the crankshaft shown in FIG. 2, and FIGS. 3B and 3C are shown in FIGS. 3B and 3C in the crankshaft shown in FIG. It is a schematic diagram which shows an example of the structure when is divided into a plurality of surfaces. It is a schematic diagram which shows an example of the structure of the freezing / refrigerating apparatus provided with the refrigerant compressor shown in FIG. 1.

The closed type refrigerant compressor according to the present disclosure stores lubricating oil having a kinematic viscosity of 1 mm ² / S to 9 mm ² / S at 40 ° C. in a closed container, and is driven by an electric element and the electric element as a refrigerant. The compression element accommodates a compression element having a spindle and an eccentric shaft as a shaft portion, and the main bearing and the eccentric shaft supporting the spindle as a bearing portion supporting the shaft portion. The sliding surface of the spindle with the main bearing is divided into a single surface or a plurality of surfaces, and the sliding surface is a single surface. , When the axial length of the sliding surface is a single sliding length L, or when the sliding surface is divided into a plurality of surfaces, the axial length is the minimum. When the axial length of the moving surface is a single sliding length L, the ratio L / D between the single sliding length L and the outer diameter D of the main shaft is 0.51 or less. Further, the lubricating oil is configured to contain sulfur or a compound having sulfur as a slidability modifier.

According to the above configuration, the lubricating oil has a low viscosity, and the ratio L / of the single sliding length L to the outer diameter D regardless of whether the sliding surface of the main shaft is a single surface or a plurality of surfaces. D is 0.51 or less, and the lubricating oil contains a sulfur-based slidable modifier. As a result, even if the viscosity of the lubricating oil is reduced and the sliding area is reduced so that the ratio L / D is 0.51 or less, the sulfur-based slidability modifier is good in the sliding portion. Abrasion resistance can be realized. As a result, it is possible to obtain a closed-type refrigerant compressor capable of improving the reliability of the shaft portion pivotally supported by the bearing portion even if a lubricating oil having a lower viscosity is used.

In the closed-type refrigerant compressor having the above configuration, when the sliding surface is divided into a plurality of surfaces, the total axial length of the plurality of sliding surfaces is further added to the total sliding length Lt. , The ratio Lt / D of the total sliding length Lt and the outer diameter D may be 1.26 or less.

According to the above configuration, when the sliding surfaces are a plurality of surfaces, the ratio L / D is 0.51 or less, and the ratio Lt / of the total sliding length Lt and the outer diameter D is further increased. The sliding area is reduced so that D is 1.26 or less. As a result, the wear resistance of the sliding portion derived from the sulfur-based slidability modifier can be further improved in a state where the sliding area is reduced by using a low-viscosity lubricating oil. can.

Further, in the closed type refrigerant compressor having the above configuration, the ratio L / D may be 0.15 or more.

According to the above configuration, when the ratio L / D is 0.15 or more, the sliding area is not excessively reduced. Therefore, in a state where the sliding area is reduced by using a low-viscosity lubricating oil, the wear resistance of the sliding portion can be suitably realized by the sulfur-based slidability modifier.

Further, in the closed type refrigerant compressor having the above configuration, the ratio Lt / D may be 0.3 or more.

According to the above configuration, when the ratio Lt / D is 0.3 or more, the sliding area is not excessively reduced even when the sliding surface is divided into a plurality of surfaces. Therefore, in a state where the sliding area is reduced by using a low-viscosity lubricating oil, the wear resistance of the sliding portion can be suitably realized by the sulfur-based slidability modifier.

Further, in the closed-type refrigerant compressor having the above configuration, the content of the slidability modifier may be 100 ppm or more in terms of the weight of the sulfur element.

According to the above configuration, a sulfur-based slidability modifier is added to the lubricating oil so that the weight of the sulfur element is 100 ppm or more when converted to the weight of the element sulfur. As a result, the wear resistance of the sliding portion derived from the sulfur-based slidability modifier can be suitably realized in a state where the sliding area is reduced by using a low-viscosity lubricating oil.

Further, in the closed-type refrigerant compressor having the above configuration, the lubricating oil may further contain a phosphorus-based extreme pressure additive.

According to the above configuration, by adding a phosphorus-based extreme pressure additive to the lubricating oil in addition to the sulfur-based slidability modifier, good wear reduction and the like can be realized in the sliding portion. Can be done.

Further, in the closed-type refrigerant compressor having the above configuration, the electric element may be configured to be driven by an inverter at a plurality of operating frequencies.

According to the above configuration, wear resistance derived from the sulfur-based slidability modifier can be realized in the sliding portion even during low-speed operation or high-speed operation in the inverter drive. Therefore, the reliability of the closed type refrigerant compressor can be improved.

The refrigerating / refrigerating apparatus according to the present disclosure includes a closed-type refrigerant compressor, a radiator, a decompression device, and a heat absorber having the above-described configuration, and is provided with a refrigerant circuit in which these are connected in a ring shape by piping. good.

According to the above configuration, the closed-type refrigerant compressor uses a low-viscosity lubricating oil to reduce the sliding area, and has good shaft reliability. By providing the freezing / refrigerating apparatus with a closed-type refrigerant compressor having such high efficiency and good reliability, its power consumption can be reduced and its reliability can be made high.

Hereinafter, typical embodiments of the present invention will be described with reference to the drawings. In the following, the same or corresponding elements are designated by the same reference numerals throughout all the figures, and the overlapping description thereof will be omitted.

(Embodiment 1)
[Construction of refrigerant compressor]
First, a typical configuration example of the closed-type refrigerant compressor according to the first embodiment of the present disclosure will be specifically described with reference to FIGS. 1 and 2. FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a closed-type refrigerant compressor 100 (hereinafter, may be abbreviated as a refrigerant compressor 100) according to the first embodiment of the present disclosure. FIG. 2 is a schematic side view showing an example of the configuration of the crankshaft 108, which is the shaft portion of the refrigerant compressor 100.

As shown in FIG. 1, the refrigerant compressor 100 fills a closed container 101 with, for example, R600a as a refrigerant, and stores mineral oil as a lubricating oil 103 at the bottom thereof. In the present disclosure, the lubricating oil 103 has a kinematic viscosity at 40 ° C. in the range of 1 mm ² / S to 9 mm ² / S. In the first embodiment, the lubricating oil 103 is a low-viscosity mineral oil, but the lubricating oil 103 is not limited to this, as will be described later. Further, as will be described later, the lubricating oil 103 contains at least a sulfur-based slidability modifier (or wear inhibitor), but may further contain an extreme pressure additive.

Further, the electric element 106 and the compression element 107 are housed in the closed container 101. The electric element 106 is composed of a stator 104 and a rotor 105. The compression element 107 has a reciprocating configuration driven by an electric element 106, and includes a crankshaft 108, a cylinder block 112, a piston 120, and the like.

As shown in FIG. 2, the crankshaft 108 is composed of a main shaft 109 to which the rotor 105 is press-fitted and fixed, and an eccentric shaft 110 formed eccentrically with respect to the main shaft 109. In the first embodiment, the outer peripheral surface of the main shaft 109 of the crankshaft 108 includes the first sliding surface 111a, the second sliding surface 111b, and the non-sliding outer peripheral surface 111c. A refueling pump (not shown) is provided at the lower end of the crankshaft 108.

In the first embodiment, the cylinder block 112 is made of, for example, cast iron, forms a substantially cylindrical bore 113, and includes a main bearing 114 that pivotally supports the main shaft 109 of the crankshaft 108. The inner peripheral surface of the main bearing 114 is slidably in contact with the first sliding surface 111a and the second sliding surface 111b of the outer peripheral surface of the spindle 109, but is not in contact with the non-sliding outer peripheral surface 111c. ..

As shown in FIG. 1, the eccentric shaft 110 of the crankshaft 108 is located above the refrigerant compressor 100, and the main shaft 109 is located below the refrigerant compressor 100. Therefore, this vertical positional relationship (direction) is also used when explaining the position of the crankshaft 108. For example, the upper end of the eccentric shaft 110 faces the inner upper surface of the closed container 101, and the lower end of the eccentric shaft 110 is connected to the main shaft 109. The upper end of the main shaft 109 is connected to the eccentric shaft 110, the lower end of the main shaft 109 faces the inner lower surface of the closed container 101, and the lower end of the main shaft 109 is immersed in the lubricating oil 103.

In the present disclosure, the "sliding surface" means a surface of the outer peripheral surface of the shaft portion that is slidably in contact with the inner peripheral surface of the bearing portion. The non-sliding outer peripheral surface 111c constitutes a part of the outer peripheral surface of the main shaft 109, but unlike the first sliding surface 111a and the second sliding surface 111b, the non-sliding outer peripheral surface 111c does not come into contact with the inner peripheral surface of the bearing portion. It is a recessed (or recessed) surface from the sliding surface (first sliding surface 111a and second sliding surface 111b). In other words, the diameter or radius of the portion of the spindle 109 that becomes the sliding surface is larger than the diameter or radius of the portion that becomes the non-sliding outer peripheral surface 111c.

A piston 120 is reciprocally inserted into the bore 113, whereby a compression chamber 121 is formed. The piston pin 115 has, for example, a substantially cylindrical shape and is arranged in parallel with the eccentric axis 110. The piston pin 115 is rotatably locked to the piston pin hole formed in the piston 120.

The connecting means 117 is made of, for example, a cast aluminum product, includes an eccentric bearing 119 that pivotally supports the eccentric shaft 110, and connects the eccentric shaft 110 and the piston 120 via a piston pin 115. The end face of the bore 113 is sealed with a valve plate 122.

In the present disclosure, the main shaft 109 and the eccentric shaft 110 included in the crankshaft 108 are collectively referred to as a "shaft portion". Further, the main bearing 114 of the cylinder block 112 that pivotally supports the spindle 109 and the eccentric bearing 119 of the connecting means 117 that pivotally supports the eccentric shaft 110 are collectively referred to as a "bearing portion".

The cylinder head 123 forms a high pressure chamber (not shown) and is fixed to the opposite side of the bore 113 in the valve plate 122. The suction tube (not shown) is fixed to the closed container 101 and connected to the low pressure side (not shown) of the refrigeration cycle to guide the refrigerant gas into the closed container 101. The suction muffler 124 is sandwiched between the valve plate 122 and the cylinder head 123.

Here, the main shaft 109 and the main bearing 114 of the crankshaft 108, the piston 120 and the bore 113, the piston pin 115 and the connecting rod of the connecting means 117, the eccentric shaft 110 of the crankshaft 108 and the eccentric bearing 119 of the connecting means 117 are all included. Form sliding parts with each other.

In the refrigerant compressor 100 having such a configuration, first, since the electric power supplied from a commercial power source (not shown) is supplied to the electric element 106, the rotor 105 of the electric element 106 is rotated. The rotor 105 rotates the crankshaft 108, and the eccentric motion of the eccentric shaft 110 drives the piston 120 from the connecting means 117 via the piston pin 115. The piston 120 reciprocates in the bore 113, sucks the refrigerant gas guided into the closed container 101 through the suction tube from the suction muffler 124, and compresses it in the compression chamber 121.

The specific driving method of the refrigerant compressor 100 is not particularly limited. For example, the refrigerant compressor 100 may be driven by simple on / off control, but may be driven by an inverter at a plurality of operating frequencies. In the inverter drive, in order to optimize the operation control of the refrigerant compressor 100, a low-speed operation in which the amount of oil supplied to each sliding portion is small or a high-speed operation in which the rotation speed of the electric element 106 increases occurs. do. Here, in the refrigerant compressor 100, as will be described later, the wear resistance of the spindle 109 can be made better, so that the reliability of the refrigerant compressor 100 can be improved.

Of the plurality of sliding portions included in the refrigerant compressor 100, the main shaft 109 of the crankshaft 108 is rotatably fitted to the main bearing 114 to form the sliding portion. Therefore, for convenience of explanation, the sliding portion composed of the spindle 109 and the spindle 114 is referred to as a "spindle sliding portion". Similarly, the eccentric shaft 110 of the crankshaft 108 is rotatably fitted to the eccentric bearing 119 to form a sliding portion. Therefore, for convenience of explanation, the sliding portion composed of the eccentric shaft 110 and the eccentric bearing 119 is referred to as an "eccentric shaft sliding portion". Further, the "sliding portion of the spindle" and the "sliding portion of the eccentric shaft" are collectively referred to as the "sliding portion of the shaft portion".

As the crankshaft 108 rotates, the lubricating oil 103 is supplied to each sliding portion from the lubrication pump. As a result, each sliding portion is lubricated. The lubricating oil 103 controls the seal between the piston 120 and the bore 113.

[Structure of sliding part of shaft]
Next, an example of a specific configuration of the shaft portion sliding portion according to the present disclosure will be specifically described with reference to FIGS. 3A to 3C. 3A is a schematic view showing an example of a configuration in which the sliding surface is a single surface in the crankshaft 108 shown in FIG. 2, and FIGS. 3B and 3C are slides in the crankshaft 108 shown in FIG. It is a schematic diagram which shows an example of the structure when the moving surface is divided into a plurality of surfaces.

In the example shown in FIG. 2, since the main shaft 109 of the crankshaft 108, which is a shaft portion, has the first sliding surface 111a and the second sliding surface 111b, the sliding surfaces of the main shaft 109 are formed on a plurality of surfaces. It can be said that it is divided. The configuration of the spindle 109 shown in FIG. 2, that is, the configuration in which the sliding surface is divided into two surfaces, corresponds to the schematic diagram shown in FIG. 3B. The shaft portion according to the present disclosure is not limited to this, and may be a single surface. For example, as shown in FIG. 3A, the outer peripheral surface of the main shaft 109 may not be divided into a plurality of sliding surfaces, and may have only a single sliding surface 111.

The specific configuration for dividing the sliding surface into a plurality of parts is not particularly limited, but typically, a recessed (recessed) recess is formed between the plurality of sliding surfaces on the central axis side of the sliding surface. do it. As shown in FIGS. 2 and 3B, this recess constitutes a non-sliding outer peripheral surface 111c. The specific shape of the recess is not particularly limited, and the depth thereof may be any depth as long as the rigidity, strength, and the like of the spindle 109 are not affected. Similarly, the width of the recess (that is, the distance between the plurality of sliding surfaces) is not particularly limited, and is appropriately set according to the degree to which the width (sliding area) of the sliding surfaces is narrowed (decreased or reduced). can do.

When the sliding surface is divided into a plurality of parts, the specific number of sliding surfaces is not particularly limited. As shown in FIGS. 2 and 3B, the first sliding surface 111a and the second sliding surface 111b may be divided into a total of two surfaces, or as shown in FIG. 3C, the first sliding surface 111d, The second sliding surface 111e and the third sliding surface 111f may be divided into a total of three surfaces, or may be divided into four or more surfaces. In the configuration shown in FIG. 3C, the first non-sliding outer peripheral surface 111g, which is a recess similar to the non-sliding outer peripheral surface 111c, is located between the first sliding surface 111d and the second sliding surface 111e. The second non-sliding outer peripheral surface 111h is located between the second sliding surface 111e and the third sliding surface 111f.

Here, in the shaft portion according to the present disclosure, by setting the ratio of the axial length of the sliding surface to the outer diameter (diameter) of the portion to be the sliding surface to a predetermined value or less, the wear resistance is substantially improved. The sliding area can be reduced without any particular effect. Specifically, when the sliding surface is a single surface (see, for example, FIG. 3A), the axial length of the sliding surface is set to a single sliding length L, and the sliding surfaces are a plurality of surfaces. In the case of being divided into (for example, FIG. 3B or FIG. 3C), the axial length of the sliding surface having the minimum axial length is defined as a single sliding length L. Then, when the outer diameter (diameter) of the portion to be the sliding surface in the shaft portion is set to the outer diameter D, the ratio L / D of the single sliding length L and the outer diameter D of the shaft portion is 0. The shaft portion is designed so as to be 51 or less.

In FIG. 3A, for convenience of explaining the outer diameter D and the single sliding length L, the length L (single sliding length L) of the single sliding surface 111 is shown larger than the outer diameter D. If it is as shown in FIG. 3A, the ratio L / D exceeds 0.51. However, in reality, for example, by forming a recess (non-sliding outer peripheral surface) in the upper part (eccentric shaft 110 side) or the lower part (lubricating oil 103 side) of the main shaft 109 when viewed from the single sliding surface 111, The ratio L / D can be set to 0.51 or less (L / D ≦ 0.51).

In FIG. 3B, the sliding surface is divided into a first sliding surface 111a and a second sliding surface 111b. Of these, in the example shown in FIG. 3B, the axial length La of the upper first sliding surface 111a is smaller than the axial length Lb of the lower second sliding surface 111b (La <Lb). In this case, since the first sliding surface 111a is the "sliding surface having the smallest length", its length La corresponds to the single sliding length L (L = La). In this example, La / D may be 0.51 or less on the first sliding surface 111a.

Also in FIG. 3B, similarly to FIG. 3A, the length La of the outer diameter D and the first sliding surface 111a is shown larger than the outer diameter D for convenience of explanation. Also in this case, the ratio L / D can be increased by increasing the axial length of the non-sliding outer peripheral surface 111c or by providing a non-sliding outer peripheral surface (recess) on the upper side of the first sliding surface 111a. Can be set to 0.51 or less.

In FIG. 3C, the sliding surface is divided into a first sliding surface 111d, a second sliding surface 111e, and a third sliding surface 111f. Of these, in the example shown in FIG. 3C, the length Le of the second sliding surface 111e in the central portion is smaller than the axial length Ld of the upper first sliding surface 111d, and the length Ld is the lower side. It is smaller than the length Lf of the third sliding surface 111f (Le <Ld <Lf). In this case, since the second sliding surface 111e is the "sliding surface having the smallest length", its length Le corresponds to the single sliding length L (L = Le). In this example, the Le / D on the second sliding surface 111e may be 0.51 or less.

In the present disclosure, the lower limit of the ratio L / D is not particularly limited, but 0.15 or more can be mentioned as an example of a preferable lower limit. Therefore, the preferred range of the ratio L / D in the present disclosure may be in the range of 0.15 to 0.51. Further, 0.30 can be mentioned as a more preferable lower limit of the ratio L / D, and 0.42 can be mentioned as a more preferable lower limit.

When the ratio L / D exceeds 0.51, the lubricating oil 103 having a low viscosity (kinematic viscosity at 40 ° C. is in the range of 1 mm ² / S to 9 mm ² / S) will be described later. Even if a sulfur-based slidability modifier is added to the lubricating oil 103, sufficient wear resistance cannot be obtained. On the other hand, if the ratio L / D is less than 0.15, the sliding surface may become too narrow, depending on various conditions of the shaft portion. Generally, when the ratio L / D is 0.15 or more, the sliding area is not excessively reduced. Therefore, even if a low-viscosity lubricating oil 103 is used, the sulfur-based slidability Abrasion resistance of the sliding portion of the shaft portion can be suitably realized by the modifier.

In the present disclosure, when the sliding surface is divided into a plurality of surfaces, in addition to the condition that the ratio L / D is 0.51 or less, the total length of the plurality of sliding surfaces in the axial direction is totaled. When the sliding length Lt is set, it is preferable that the condition that the ratio Lt / D of the total sliding length Lt and the outer diameter D is 1.26 or less (Lt / D ≦ 1.26) is satisfied.

For example, in the example shown in FIG. 3B, the sum of the length La of the first sliding surface 111a and the length Lb of the second sliding surface 111b is the total sliding length Lt (Lt = La + Lb). Therefore, in this example, La + Lb ≦ 1.26 may be sufficient. Further, in the example shown in FIG. 3C, the sum of the length La of the first sliding surface 111d, the length Le of the second sliding surface 111e, and the length Lf of the third sliding surface 111f is the total sliding length. It becomes Lt (Lt = Ld + Le + Lf). Therefore, in this example, Ld + Le + Lf ≦ 1.26 may be sufficient.

As described above, when the sliding surfaces are a plurality of surfaces, if the ratio L / D is 0.51 or less and the ratio Lt / D is 1.26 or less, the lubricating oil 103 has a low viscosity. In the state where the sliding area is reduced by using, the wear resistance of the shaft portion sliding portion derived from the sulfur-based slidability modifier can be further improved.

In the present disclosure, the lower limit of the ratio Lt / D is not particularly limited, but as an example of a preferable lower limit, 0.3 or more can be mentioned. Therefore, the preferred range of the ratio Lt / D in the present disclosure may be in the range of 0.3 to 1.26. Further, a more preferable lower limit of the ratio Lt / D can be 0.60, and a further preferable lower limit can be 0.99. Generally, when the ratio Lt / D is 0.3 or more, the sliding area is not excessively reduced even when the sliding surface is divided into a plurality of surfaces. Therefore, even if a low-viscosity lubricant is used as the lubricating oil 103, the wear resistance of the sliding portion of the shaft portion can be suitably realized by the sulfur-based slidability modifier.

In the examples shown in FIGS. 3A to 3C, the ratio L / D or the ratio Lt / D is described for the main shaft 109 of the crankshaft 108 as the shaft portion, but the present disclosure is not limited to this. The same applies to the eccentric shaft 110. That is, when the sliding surface of the eccentric shaft 110 with the eccentric bearing 119 is a single surface, the axial length of the sliding surface is set to the single sliding length L, or the eccentric shaft 110. When the sliding surface is divided into a plurality of surfaces, the single sliding surface is defined as the single sliding length L of the sliding surface having the minimum axial length. The ratio L / D of the moving length L and the outer diameter D of the eccentric shaft 110 may be 0.51 or less. Further, when the total of the axial lengths of the plurality of sliding surfaces on the eccentric shaft 110 is the total sliding length Lt, the ratio Lt / of the total sliding length Lt to the outer diameter D of the eccentric shaft 110 It suffices if D is 1.26 or less.

Therefore, in the refrigerant compressor 100 according to the present disclosure, the ratio L / D may be 0.51 or less on at least one of the main shaft 109 and the eccentric shaft 110, which are shaft portions, and the ratio Lt / D is 1.26. It suffices that at least one of the main shaft 109 and the eccentric shaft 110 satisfies the following.

[Construction of lubricating oil]
Next, a more specific configuration of the lubricating oil 103 stored in the closed container 101 will be specifically described.

The lubricating oil 103 according to the present disclosure is not particularly limited as long as the kinematic viscosity at 40 ° C. is in the range of 1 mm ² / S to 9 mm ² / S. As the typical lubricating oil 103, for example, at least one oily substance selected from the group consisting of mineral oil, alkylbenzene oil, and ester oil can be preferably used. Only one kind of these oily substances may be used, or two or more kinds may be used in combination as appropriate. The combination of two or more kinds of oily substances referred to here is not only when, for example, two or more kinds of different oily substances corresponding to mineral oil are combined, but also, for example, one or more kinds of oily substances corresponding to mineral oil correspond to alkylbenzene oil. It also includes the case of combining one or more kinds of oily substances (or one or more kinds of oily substances corresponding to ester oil).

The lubricating oil 103 according to the present disclosure contains a sulfur-based slidability modifier in addition to the above-mentioned oily substance. The sulfur-based slidability modifier may be any material as long as it can react with the material used for the shaft portion (shaft portion material) and sulfur. Therefore, the slidability modifier may be sulfur itself or a sulfur compound containing sulfur and capable of reacting with the shaft material. For example, if the material of the shaft portion is an iron-based material, the sulfur compounds that can be used as the slidability modifier include olefin sulfide, sulfide-based compounds (for example, dibenzyl (di) sulfide (DBDS), etc.), and xanthate. , Thiadiazole, thiocarbonate, sulfurized oil and fat, sulfurized ester, dithiocarbamate, sulfurized terpene and the like.

The content of the sulfur-based slidability modifier in the lubricating oil 103 is not particularly limited, but preferably, the slidability modifier is used as the lubricating oil 103 so as to be 100 ppm or more when converted to the sulfur element weight. It may be added to. The lower limit of the addition amount (content) of the slidable modifier, which is 100 ppm in terms of the weight of the sulfur element, is larger than the upper limit of the general addition amount of the sulfur-based extreme pressure additive described later. Is.

If the content (addition amount) of the slidability modifier is less than 100 ppm when converted to the sulfur element weight, a low-viscosity lubricant 103 is used as the lubricating oil 103, although it depends on various conditions. In a state where the sliding area of the sliding portion is reduced, it may not be possible to realize suitable wear resistance of the sliding portion of the shaft portion. Further, as the lower limit of the preferable content of the sulfur-based slidability modifier, for example, 150 ppm or more when converted to the weight of the sulfur element can be mentioned. Further, as the upper limit of the preferable content of the sulfur-based slidability modifier, for example, 1000 ppm or less when converted to the weight of the sulfur element can be mentioned, and more preferably 500 ppm or less can be mentioned.

As the sulfur-based slidability modifier used in the present disclosure, it is possible to use the same compound as the known sulfur-based extreme pressure additive, but the shaft material is more than the known extreme pressure additive. It is possible to use a substance having a relatively high reactivity of the above, or to add a known extreme pressure additive to the lubricating oil 103 in an amount larger than a general addition amount (content).

Generally, an extreme pressure additive is a compound containing active elements such as sulfur, halogen element, and phosphorus, and chemically reacts with a material surface (sliding surface) constituting a sliding portion to form a film. This coating suppresses wear, seizure, fusion, etc. of the sliding member.

Here, it is also known that the sulfur-containing compound easily reacts with copper. For example, in Reference 1: Japanese Patent Application Laid-Open No. 2006-117720, although a sulfur-containing wear inhibitor is effective in preventing corrosive wear of a sliding material containing lead, a non-ferrous base metal-containing sliding material other than lead is effective. For example, it is disclosed that sulfide corrosion is likely to occur with respect to copper and the like (paragraphs [0006] to [0007]).

In the refrigerant compressor 100, a copper wire is used as a winding of the electric element 106. Further, in a freezing / refrigerating apparatus using a refrigerant compressor 100, a copper pipe is generally used as a refrigerant pipe. As mentioned above, copper easily corrodes by reacting with sulfur-containing compounds. Therefore, when using a sulfur-based extreme pressure additive, a copper member (or copper) provided in the refrigerant compressor 100 or a refrigerating / refrigerating apparatus is used. It is necessary to take measures to avoid or suppress the corrosion of the contained member) and not to reduce its reliability.

As disclosed in Reference 2: Patent 5671695, the applicant shall react with copper in the refrigerant circulation path when a sulfur-based additive is used as the extreme pressure additive for the refrigerating machine oil of the refrigerating / refrigerating apparatus. A sulfur-based extreme pressure additive having a sulfur cross-linking number of 3 or less is used so that there is no such problem, and a metal inactivating agent is preferably used in combination.

On the other hand, as a result of diligent studies by the present inventors including experimental verification, a low-viscosity lubricant was used as the lubricating oil 103, and the shaft was set so that the above-mentioned ratio L / D was 0.51 or less. When the sliding area of the sliding part is reduced, a sulfur-based compound with higher reactivity may be used as the slidability modifier, or the addition amount (content) may be increased. It has been clarified that not only good wear resistance can be realized, but also corrosion of the copper member (or copper-containing member) can be substantially avoided.

Further, in the refrigerant compressor 100 according to the present disclosure, a known extreme pressure additive may be added to the lubricating oil 103 in addition to the sulfur-based slidability modifier. As a specific extreme pressure additive, a known one can be preferably used, and the present invention is not particularly limited, but for example, a phosphorus compound such as a phosphoric acid ester, a chlorine-based hydrocarbon, or a halogenation of a fluorine-based hydrocarbon or the like. Compounds and the like can be mentioned. Only one kind of these extreme pressure additives may be added to the lubricating oil composition, or two or more kinds may be added in an appropriate combination.

Among these extreme pressure additives, phosphorus compounds can be preferably used. Typical phosphorus compounds include tricresyl phosphate (TCP), tributyl phosphine (TBP), and triphenyl phosphine (TPP), and among them, TCP can be used more preferably. By adding a phosphorus-based extreme pressure additive to the lubricating oil 103 in addition to the sulfur-based slidability modifier, good wear reduction and the like can be realized in the shaft portion sliding portion.

The amount of the extreme pressure additive added to the lubricating oil composition is not particularly limited, but for example, when the lubricating oil 103 (oily substance) is a low polar substance such as mineral oil or alkylbenzene oil, the addition amount is suitable. The range of 0.5 to 8.0% by weight can be mentioned, and 1 to 3% by weight can be mentioned as a more preferable range.

In addition, in the refrigerant compressor 100 according to the present disclosure, various known additives may be added to the lubricating oil 103 in addition to the slidable modifier and the extreme pressure additive. As such an additive, various substances known in the field of lubricating oil 103 can be preferably used, but typically, an oily agent, an antioxidant, an acid scavenger, a metal deactivator, and a defoamer can be used. Examples include foaming agents, corrosion inhibitors, dispersants and the like. In other words, the lubricating oil 103 used in the refrigerant compressor 100 according to the present disclosure is a lubricating oil composition composed of at least an oily substance and a slidable modifier, and the lubricating oil composition is an extreme pressure. It may contain an additive (particularly a phosphorus-based extreme pressure additive), or may contain other additives.

As described above, in the refrigerant compressor 100 according to the present disclosure, (1) the lubricating oil 103 is used under the condition that the kinematic viscosity at 40 ° C. is in the range of 1 mm ² / S to 9 mm ² / S. (2) The condition that the ratio L / D of the single sliding length L and the outer diameter D of the shaft portion is 0.51 or less, and (3) the condition that a sulfur-based slidability modifier is used. When the sliding surface is divided into a plurality of surfaces, it is preferable that (4) the ratio Lt / D of the total sliding length Lt and the outer diameter D is 1.26 or less. Meet. By satisfying these conditions, the shaft portion and the bearing portion can be satisfactorily lubricated, so that wear of the shaft portion sliding portion can be satisfactorily suppressed. As a result, the reliability of the refrigerant compressor 100 can be further improved.

As described above, the refrigerant compressor 100 according to the present disclosure may be driven by an inverter at a plurality of operating frequencies. In the inverter drive, there are cases where the electric element 106 is operated at a low rotation speed (low speed operation) and a case where the electric element 106 is operated at a high rotation speed (high speed operation). The supply amount of the lubricating oil 103 to the moving portion decreases. In the present disclosure, the sliding area of the sliding portion of the shaft portion is small, but good wear resistance can be realized even if the supply amount of the lubricating oil 103 is reduced.

Further, even when the rotation speed is changed from the low rotation speed to the high rotation speed (when the rotation speed of the electric element 106 increases), good wear resistance can be realized. Therefore, even during low-speed operation or high-speed operation in inverter drive, wear resistance derived from the sulfur-based slidability modifier can be realized in the shaft portion sliding portion. As a result, the reliability of the refrigerant compressor 100 can be improved, and the operating efficiency can be improved.

As described above, in the refrigerant compressor 100 according to the present disclosure, the lubricating oil 103 has a low viscosity and has a single sliding length regardless of whether the sliding surface of the shaft portion is a single surface or a plurality of surfaces. The ratio L / D of the L to the outer diameter D is 0.51 or less, and the lubricating oil 103 contains a sulfur-based slidability modifier. As a result, even if the viscosity of the lubricating oil 103 is reduced and the sliding area is reduced so that the ratio L / D is 0.51 or less, the sulfur-based slidability modifier is good in the sliding portion. Abrasion resistance can be realized. As a result, it is possible to obtain a closed-type refrigerant compressor capable of improving the reliability of the shaft portion pivotally supported by the bearing portion even if the lubricating oil 103 having a lower viscosity is used.

(Embodiment 2)
In the second embodiment, an example of the freezing / refrigerating apparatus provided with the refrigerant compressor 100 described in the first embodiment will be specifically described with reference to FIG. FIG. 4 schematically shows a schematic configuration of a freezing / refrigerating apparatus including the refrigerant compressor 100 according to the first embodiment. Therefore, in the second embodiment, only the outline of the basic configuration of the freezing / refrigerating apparatus will be described.

As shown in FIG. 4, the freezing / refrigerating apparatus according to the second embodiment includes a main body 275, a partition wall 278, a refrigerant circuit 270, and the like. The main body 275 is composed of a heat-insulating box body, a door body, and the like. The box body has a structure in which one side thereof is open, and the door body has a structure in which the opening of the box body is opened and closed. The inside of the main body 275 is divided into a storage space 276 for articles and a machine room 277 by a partition wall 278. A blower (not shown) is provided in the storage space 276. The inside of the main body 275 may be partitioned into a space other than the storage space 276 and the machine room 277.

The refrigerant circuit 270 is configured to cool the inside of the storage space 276, and includes, for example, the refrigerant compressor 100, the radiator 272, the decompression device 273, and the heat absorber 274 described in the first embodiment. Is connected by piping in a ring shape. The endothermic device 274 is arranged in the storage space 276. The cooling heat of the endothermic 274 is agitated to circulate in the storage space 276 by a blower (not shown), as shown by the dashed arrow in FIG. As a result, the inside of the storage space 276 is cooled.

As described in the first embodiment, the refrigerant compressor 100 included in the refrigerant circuit 270 has a kinematic viscosity of 1 mm ² / S to 9 mm ² / S at 40 ° C. as the lubricating oil 103. The condition that the material is used, (2) the ratio L / D of the single sliding length L and the outer diameter D of the shaft portion is 0.51 or less, and (3) the slidability of the sulfur system. When the condition of using a modifier is satisfied and the sliding surface is divided into a plurality of surfaces, (4) the ratio Lt / D of the total sliding length Lt and the outer diameter D is preferably (4). It meets the condition of 1.26 or less. As a result, the reliability of the refrigerant compressor 100 can be further improved.

As described above, the freezing / refrigerating apparatus according to the second embodiment is equipped with the refrigerant compressor 100 according to the first embodiment. In this refrigerant compressor 100, the sliding area of the shaft portion sliding portion is reduced by using a low-viscosity lubricating oil 103, and the shaft portion has good reliability. By providing the freezing / refrigerating apparatus with a closed-type refrigerant compressor having such high efficiency and good reliability, its power consumption can be reduced and its reliability can be made high.

The present invention is not limited to the description of the embodiment, and various modifications can be made within the scope of the claims, and the present invention is disclosed in different embodiments and a plurality of modifications. Embodiments obtained by appropriately combining the above technical means are also included in the technical scope of the present invention.

Also, from the above description, many improvements and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description should be construed as an example only and is provided for the purpose of teaching those skilled in the art the best aspects of carrying out the present invention. The details of its structure and / or function can be substantially changed without departing from the spirit of the present invention.

As described above, according to the present invention, it is possible to provide a refrigerant compressor having excellent reliability while using a low-viscosity lubricating oil, and a refrigerating / refrigerating apparatus using the refrigerant compressor. Therefore, the present invention can be widely applied to various devices using a refrigeration cycle.

100: Refrigerant compressor 101: Sealed container 103: Lubricating oil 106: Electric element 107: Compression element 108: Crankshaft 109: Main shaft (shaft portion)
110: Eccentric axis (shaft part)
111: Single sliding surface 111a: First sliding surface 111b: Second sliding surface 111c: Non-sliding outer peripheral surface 111d: First sliding surface 111e: Second sliding surface 111f: Third sliding surface 111g : First non-sliding outer peripheral surface 111h: Second non-sliding outer peripheral surface 112: Cylinder block 114: Main bearing (bearing portion)
119: Eccentric bearing (bearing part)
270: Refrigerant circuit 272: Heat sink 273: Decompression device 274: Heat absorber

Claims (9)

Lubricating oil having a kinematic viscosity of 1 mm ² / S to 9 mm ² / S at 40 ° C. is stored in a closed container, and an electric element and a compression element driven by the electric element to compress a refrigerant are housed and sealed. The container contains copper or copper-containing members,
The compression element pivotally supports a crank shaft having a spindle and an eccentric shaft as a shaft portion made of an iron-based material, and a main bearing that pivotally supports the spindle and the eccentric shaft as a bearing portion that supports the shaft portion. With eccentric bearings,
The sliding surface of the spindle with the main bearing is divided into a first sliding surface and a second sliding surface via a non-sliding outer peripheral surface recessed so as not to contact the inner peripheral surface of the bearing portion. Bearing,
When the axial length of the sliding surface having the smallest axial length among the first sliding surface and the second sliding surface is a single sliding length L, the single sliding The ratio L / D of the length L to the outer diameter D of the main shaft is 0.51 or less.
Further, the lubricating oil is characterized by containing sulfur or a compound having sulfur as a slidability modifier at 100 ppm or more in terms of the weight of the elemental sulfur.
Sealed refrigerant compressor. The slidable modifier is at least one of a sulfurized olefin, a sulfide compound, xanthate, thiadiazole, thiocarbonate, a sulfurized oil and fat, a sulfurized ester, a dithiocarbamate, and a terpene sulfide.
The sealed refrigerant compressor according to claim 1. The sliding surface is divided into a plurality of surfaces of the first sliding surface and the second sliding surface, and the total of the axial lengths of the plurality of sliding surfaces is defined as the total sliding length Lt. It is characterized in that the ratio Lt / D of the total sliding length Lt and the outer diameter D is 1.26 or less.
The sealed refrigerant compressor according to claim 1 or 2. The ratio L / D is 0.15 or more.
The closed-type refrigerant compressor according to any one of claims 1 to 3. The ratio Lt / D is 0.3 or more.
The sealed refrigerant compressor according to claim 3. The content of the slidable modifier is 1000 ppm or less when converted to the weight of elemental sulfur.
The sealed refrigerant compressor according to any one of claims 1 to 5. The lubricating oil is further characterized by containing a phosphorus-based extreme pressure additive.
The closed-type refrigerant compressor according to any one of claims 1 to 6. The electric element is driven by an inverter at a plurality of operating frequencies.
The closed-type refrigerant compressor according to any one of claims 1 to 7. The present invention includes the closed-type refrigerant compressor according to any one of claims 1 to 8, a radiator, a decompression device, and a heat absorber, and is characterized by comprising a refrigerant circuit in which these are connected in a ring shape by a pipe. do,
Freezing / refrigerating equipment.

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