JP4822123B2 - Oilless compressor - Google Patents

Description

  The present invention relates to an oilless compressor having a novel piston rod structure and not using a lubricating oil.

  In recent years, compressors have been promoted to be oil-less in consideration of the environment. By not using lubricating oil, the generation of clean air that does not contain oil in the air, replacement due to deterioration and contamination of the lubricating oil, and oil drainage generated in the air tank or on the piping Surrounding oil leakage and spillage This is because various problems relating to oil such as environmental deterioration can be avoided (see, for example, Patent Document 1 and Patent Document 2).

  However, compared to the oil supply type, the oilless type is mainly designed in the low pressure region of the generated compressed air pressure, and the design in the intermediate pressure region established in the oil supply type has not been established. The oil supply type has a structure in which lubricating oil is held inside the compressor body and the parts are lubricated while splashing oil simultaneously with the operation, whereas the oilless type is a structure in which the operation is performed by self-lubricating without using the lubricating oil.

  Normally, a needle bearing is used at the small end of the oilless piston rod, and the lubrication depends on the grease held by the needle bearing itself. The strength of the needle bearing is proportional to the size to some extent.

  When selecting a needle bearing in an oilless compressor, it is necessary to fully consider the strength against pressure load from the piston due to compression, but there is a limitation in dimensions because it is built in so as to be hidden inside the piston.

  In the oilless type medium pressure region design, a large size is selected in terms of strength, but there is a conflict because a small size is desired due to dimensional restrictions.

  As disclosed in Patent Document 3, there are several types of needle bearings. Among them, there is a total roller type needle bearing that can be relatively strong and is small in size. This is a simple structure combining an outer ring and a roller, and the strength is improved by placing the roller almost all around the outer ring. It is effective for those that require strength and downsizing, such as an oilless compressor. is there.

  4 is an assembly view of a piston having a total colony dollar bearing 3, FIG. 5 is a sectional view of the total colony dollar bearing 3, and FIG. 6 is a piston rod 2 to which the total colony dollar bearing 3 is mounted. The total colony dollar bearing 3 here is composed of a roller 8 and an outer ring 9, and there is no cage for holding between the rollers. Further, in the state where the piston pin 5 is inserted, the roller is prevented from being displaced in the axial direction by the flange 10 provided on the outer ring 9. The clearance between the piston pin 5 and the outer ring 9 in the circumferential direction is filled with grease except that a roller is disposed. When the compressor starts operation, the total colony dollar bearing 3 of the piston rod small end portion 11 is swung by the action of the crankshaft having an eccentric shape.

  The total colony dollar bearing 3 that is swung by receiving a force in the circumferential direction is liable to leak grease in the axial direction. This is because the structure of the total colony dollar bearing 3 is a simple structure in which the outer ring 9 and the roller 8 are combined, and there is no retainer or the like that prevents grease leakage to some extent.

  As countermeasures, oil seals 4 are provided at both ends for the purpose of securing the leakage grease and returning it to the total colony dollar bearing 3. The oil seal 4 uses synthetic rubber for the seal portion and plays its role while contacting the outer periphery of the piston pin 5.

  For this reason, the sealing surface of the oil seal 4 needs to be lubricated, and leakage grease from the total colony dollar bearing 3 is used for that purpose.

For this reason, leakage from the sealing surface occurs slightly depending on the operation time. As for grease, when a significant temperature rise occurs due to the ambient environment and operating conditions of the compressor, the grease in the total colony dollar bearing 3 and the grease secured in the oil seal 4 are thermally expanded and leak from the seal portion of the oil seal 4 There is a risk that. Therefore, it is necessary to fill the total colony dollar bearing 3 with as much grease as possible.
Japanese Patent Publication No. 5-75916 Japanese Patent No. 2950438 JP-A-9-287570

  Since the piston rod small end portion 11 of the oilless compressor is required to have strength and downsizing, the total colony dollar bearing 3 is effective. However, compared with a normal grease-filled needle bearing, the total colony dollar bearing 3 has a very small amount of grease that can be held due to its structure, and the grease may thermally expand and leak from the seal portion 4 of the oil seal. Considering this, it is not possible to expect much in terms of life, so it is difficult to adopt it in an oilless type that generates air in the medium pressure range.

  The present invention has been made in view of the above circumstances, and its purpose is to increase the amount of grease at the piston rod small end portion 11 of the oilless compressor, and the total colony dollar bearing used is insufficiently lubricated due to grease leakage. It is an object of the present invention to provide an oilless compressor that is less likely to cause the occurrence of the problem and can extend its life.

  In order to solve the above-mentioned object, the invention of claim 1 includes a cylindrical hole provided at a small end portion of a piston rod, and a total colony dollar bearing inserted into the cylindrical hole and provided with oil seals at both end faces thereof. An oilless compressor having a piston rod structure comprising a through hole provided in a side surface of the piston and a piston pin inserted into a total colony dollar bearing to connect the piston and the piston rod, wherein the piston rod structure includes the total colony The same grease as the grease applied to the total colony dollar bearing is provided in the circumferential direction of the piston pin located between the oil seal provided on both axial end surfaces of the dollar bearing and the total colony dollar bearing. It has a filled grease groove.

  According to this configuration, the grease groove provided in the piston pin portion is filled with grease in advance, and the amount of grease is ensured more than the amount that the bearing itself can hold, thereby making it difficult to cause lubrication of the total colony dollar bearing due to grease leakage. , Life can be extended and reliability can be improved.

  In addition, since it has almost no effect on the external dimensions, it is possible to select a total roller type needle bearing that is strong against compression loads and can be reduced in size. Is possible.

  According to a second aspect of the present invention, there is provided a cylindrical hole provided in a small end portion of a piston rod, a total colony dollar bearing inserted in the cylindrical hole and provided with oil seals on both end surfaces thereof, and provided on a side surface of the piston. In the oilless compressor having a piston rod structure that is inserted into the through-hole and the total colony dollar bearing and that connects the piston and the piston rod, the piston rod structure has both end surfaces in the axial direction of the total colony dollar bearing. An oil seal is arranged so as to obtain a slight gap between the piston rod and the piston rod located in the circumferential direction inside the cylindrical hole, and the same grease as that applied to the total colony dollar bearing. And a grease groove filled with grease.

  According to this configuration, the grease groove provided inside the cylindrical hole of the piston rod is filled with grease in advance, and the amount of grease is ensured more than the amount that the bearing itself can hold, thereby reducing the lubrication of the total colony dollar bearing due to grease leakage. It is less likely to occur, the life can be extended, and the reliability can be improved.

  In addition, since it has almost no effect on the external dimensions, it is possible to select a total roller type needle bearing that has strength against compression load and can be reduced in size. Design becomes possible.

  According to a third aspect of the present invention, there is provided a cylindrical hole provided at a small end portion of a piston rod, a total colony dollar bearing inserted into the cylindrical hole and provided with oil seals at both end surfaces thereof, and provided on a side surface of the piston. In the oilless compressor having a piston rod structure, which is inserted into the through-hole and the total colony dollar bearing and connected to the piston and the piston rod, the piston rod structure includes both end surfaces in the axial direction of the total colony dollar bearing. An oil seal is arranged so as to obtain a slight gap between them, and is provided in the circumferential direction of the piston pin located in this gap and in the circumferential direction inside the cylindrical hole of the piston rod, and applied to the total colony dollar bearing. Characterized by having a grease groove filled with the same grease as the existing grease To.

  According to this configuration, the grease groove provided in the piston pin part and piston rod part is filled with grease in advance, and the amount of grease exceeds that which can be held by the bearing itself. Can be prevented, the life can be extended, and the reliability can be improved.

  In addition, since it has almost no effect on the external dimensions, it is possible to select a total roller type needle bearing that is strong against compression loads and can be reduced in size. Is possible.

  According to the first to third aspects of the present invention, the total colony dollar bearing is inserted into the cylindrical hole processed into the small end portion of the piston rod so as to be located in the central portion in the axial direction, An oil seal is arranged so as to obtain a slight gap therebetween, and a grease groove is provided in the cylindrical hole of the piston pin part or piston rod located in this gap, and further, both parts are applied to the total colony bearing. Filling with the same grease as the grease and ensuring that the amount of grease exceeds the amount that the bearing itself can hold, makes it difficult to cause insufficient lubrication of the total colony dollar bearing due to grease leakage, extending the service life and improving reliability. Can be improved.

  In addition, since it has almost no effect on the external dimensions, it is possible to select a total roller type needle bearing that has strength against compression load and can be reduced in size. Design becomes possible.

[Embodiment 1]
To achieve the above object, a first embodiment corresponding to the invention of claim 1 will be described first.
As shown in FIGS. 1 and 5, the total colony dollar bearing 3 is inserted into the processed cylindrical hole of the small end portion 11 of the piston rod 2 so as to be located at the center in the axial direction. A grease groove 12 is provided in the circumferential direction in the piston pin portion 5 positioned between the oil seals 4 provided at both end surfaces in the direction, and the same grease as that applied to the total colony dollar bearing 3 is filled.

  The grease groove 12 of the piston pin 5 determines the depth and width of the grease groove 12 as a volume capable of securing the same amount of grease applied to the total colony dollar bearing 3. The piston pin 5 has a hollow shape. When the grease groove 12 is provided, since the strength is inferior, consideration is given to obtain a sufficient strength by reducing the hollow inner diameter. The groove width of the grease groove 12 is between the axial roller end surface of the total colony dollar bearing 3 and the end surface of the oil seal. In order to prevent scratches on the roller end surface and to prevent the oil seal from falling off, The groove width has an appropriate margin from the end face.

  If the above-mentioned restrictions are satisfied, the shape of the grease groove 12 of the piston pin 5 may have a cross-sectional shape that is easy in processing such as a semicircular shape or a V shape. By providing the grease groove 12, the amount of grease is doubled with the amount held by the total colony dollar bearing 3, and it is possible to cope with grease consumption due to oil seal lubrication and grease leakage due to thermal expansion. Time can also be doubled.

  In the first embodiment, the grease groove 12 is provided on the outer peripheral surface of the piston pin 5, but since it can be realized by reducing the inner diameter of the hollow piston pin 5, the addition of new parts and the shapes and dimensions of other parts are possible. Since it can be adopted without changing the design, the design is easy. In addition, the assembly can be easily performed by using a conventional assembling technique.

[Embodiment 2]
Next, Embodiment 2 corresponding to the invention of claim 2 will be described with reference to FIG.
In the second embodiment, the total colony dollar bearing 3 is inserted into the processed cylindrical hole of the small end portion 11 of the piston rod so as to be positioned at the axial center, and slightly between the axial end faces of the total colony dollar bearing 3. The oil seal 4 is arranged so as to obtain a clear gap, and a grease groove 12 is provided in the circumferential direction inside the cylindrical hole of the piston rod 2 located in the gap so that the same grease as that applied to the total colony dollar bearing 3 is applied. Fill.

  The grease groove 12 of the piston rod 2 determines the depth and width of the grease groove 12 as a volume capable of securing the same amount as the amount of grease applied to the total colony dollar bearing 3.

  When the grease groove 12 is provided, consideration is given to obtaining sufficient strength such as increasing the thickness of the cylindrical hole machining portion of the piston rod 2 because its strength is inferior. About the width | variety of the grease groove | channel 12, it is between the outer ring axial direction end surface of the total colony dollar bearing 3, and the outer ring inner side end surface of the oil seal 4, and the crack to the outer ring surface of the total colony dollar bearing 3 and the oil seal 4 can be prevented. Thus, the groove width is set to have an appropriate margin from each end face.

  If the above-mentioned restrictions are satisfied, the shape of the grease groove 12 inside the cylindrical hole of the piston rod 2 may have a cross-sectional shape that is easy to process such as a semicircular shape or a V shape. By providing the grease groove 12, the amount of grease is doubled with the amount held by the total colony dollar bearing 3, so that grease consumption due to lubrication of the oil seal 4 and grease leakage due to thermal expansion may occur. The response time can be doubled.

  In the second embodiment, the grease grooves 12 are provided in the circumferential direction inside the cylindrical hole of the piston rod 2, but a slight gap can be obtained between the oil seals 4 provided on both end surfaces in the axial direction of the total colony dollar bearing 3. The piston rod small end portion 11 can be realized by slightly extending the dimension in the axial direction and increasing the thickness of the cylindrical hole machining portion of the piston rod 2, so that new parts can be added or other parts Since it can be adopted without changing the shape and dimensions, the design is easy. In addition, the assembly can be easily carried out by using a conventional assembling technique.

[Embodiment 3]
A third embodiment corresponding to the invention of claim 3 will be described with reference to FIG.
In the third embodiment, the total colony dollar bearing 3 is inserted into the processed cylindrical hole of the small end portion 11 of the piston rod 2 so as to be located in the central portion in the axial direction, and the grease groove is formed in the circumferential direction inside the cylindrical hole of the piston rod 2. 12a is provided, and the same grease as that applied to the total colony dollar bearing 3 is filled. Further, a grease groove 12b is also provided in the circumferential direction on the piston pin portion 5 located between the oil seals 4 provided on both end surfaces in the axial direction of the total colony dollar bearing 3, and applied to the total colony dollar bearing 3. Fill with the same grease as the existing grease.

  The grease groove 12a of the piston rod 2 and the grease groove 12b of the piston pin each determine the depth and width of the grease grooves 12a and 12b as volumes that can secure the same amount of grease applied to the total colony dollar bearing 3. .

  Since the strength of the grease grooves 12a and 12b is inferior, sufficient strength can be obtained, for example, by increasing the thickness of the cylindrical hole machining portion of the piston rod 2 or by reducing the hollow inner diameter of the piston pin 5. consider.

  The width of the grease groove 12a of the piston rod 2 is between the end surface in the outer ring axial direction of the total colony dollar bearing 3 and the inner ring end surface of the oil seal 4, and to the outer ring surfaces of the total colony dollar bearing 3 and the oil seal 4. In order to prevent scratches, the groove width should have an appropriate margin from each end face.

The width of the grease groove 12 b of the piston pin 5 is between the axial roller end surface of the total colony bearing 3 and the oil seal sheet end surface, preventing scratches on the end surface of the roller 8, and dropping off the seal surface of the oil seal 4. In order to prevent this, the groove width has an appropriate margin from each end face.
If the above restrictions are satisfied, the shape of the grease grooves 12a and 12b of the piston rod 2 and the piston pin 5 may have a cross-sectional shape that is easy to process such as a semicircular shape or a V shape.

  By providing the grease grooves 12a and 12b, the amount of grease is tripled with the amount retained by the total colony dollar bearing 3, and grease consumption due to lubrication of the oil seal 4 and grease leakage due to thermal expansion occur. However, the response time can be tripled.

According to the grease groove 12 a provided in the circumferential direction inside the cylindrical hole of the piston rod 2, the piston rod 2 can be provided with a slight clearance with respect to the oil seals 4 provided at both axial end surfaces of the total colony dollar bearing 3. According to the grease groove 12b provided on the outer peripheral surface of the piston pin 5, the small end 11 is slightly extended in the axial direction, the thickness of the cylindrical hole machining portion of the piston rod 2 is increased, and the hollow piston Since it can be realized by making the inner diameter of the pin 5 small, it can be adopted without adding a new part or changing the shape and dimensions of other parts, so that the design is easy.
When assembling, it can be easily carried out by using a conventional assembling technique.

  Further, in the first to third embodiments, the grease grooves 12, 12a, and 12b of the piston rod 2 and the piston pin 5 are enlarged by extending the small end portion 11 of the piston rod 2 in the axial direction as much as possible. In addition to the amount of grease held by the total colony dollar bearing 3, it is possible to provide an arbitrary margin.

  Further, in addition to the newly provided grease grooves 12, 12a, 12b, grease may be filled in a gap between the oil seals 4 provided on both end surfaces in the axial direction of the total colony dollar bearing 3 to increase the amount of grease.

The grease grooves 12, 12a, and 12b are assumed to be provided on both end surfaces in the axial direction of the total colony dollar bearing 3, but may be optionally provided on one side surface.
In addition to the total colony dollar bearing, the needle bearing may be a needle bearing with a cage or other bearings.

FIG. 3 is a cross-sectional view of the piston rod structure according to the first embodiment. Sectional drawing of the piston rod structure which concerns on Embodiment 2. FIG. Sectional drawing of the piston rod structure which concerns on Embodiment 3. FIG. Assembly exploded view of piston and piston rod structure. Total colony dollar bearing. Conventional piston rod structure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Piston, 2 ... Piston rod, 3 ... Total colony dollar bearing, 4 ... Oil seal, 5 ... Piston pin, 6 ... Piston pin fixing screw, 7 ... Ball, 8 ... Roller, 9 ... Outer ring, 10 ... Brim, 11 ... small end, 12, 12a, 12b ... grease groove.

Claims (3)

  A cylindrical hole provided at the small end of the piston rod, a total colony dollar bearing inserted into the cylindrical hole and provided with an oil seal on both end faces, and a through hole and a total colony dollar provided on the side surface of the piston In an oilless compressor having a piston rod structure that is inserted into a bearing and that connects a piston and a piston rod, the piston rod structure includes the oil seal provided on both end surfaces in the axial direction of the total colony dollar bearing. Oilless, characterized in that it has a grease groove provided in the circumferential direction of a piston pin located between the total colony dollar bearings and filled with the same grease as the grease applied to the total colony dollar bearings compressor.   A cylindrical hole provided at the small end of the piston rod, a total colony dollar bearing inserted into the cylindrical hole and provided with an oil seal on both end faces, and a through hole and a total colony dollar provided on the side surface of the piston In an oilless compressor having a piston rod structure that is inserted into a bearing and includes a piston pin that connects the piston and the piston rod, the piston rod structure has a slight gap between both axial end surfaces of the total colony dollar bearing. A grease groove provided in the circumferential direction inside the cylindrical hole of the piston rod located in the clearance and filled with the same grease as that applied to the total colony dollar bearing An oilless compressor characterized by comprising:   A cylindrical hole provided at the small end of the piston rod, a total colony dollar bearing inserted into the cylindrical hole and provided with an oil seal on both end faces, and a through hole and a total colony dollar provided on the side surface of the piston In an oilless compressor having a piston rod structure that is inserted into a bearing and includes a piston pin that connects the piston and the piston rod, the piston rod structure has a slight gap between both end surfaces in the axial direction of the total colony dollar bearing. The same grease as the grease applied to the total colony dollar bearing is provided in the circumferential direction of the piston pin located in the clearance and in the circumferential direction inside the cylindrical hole of the piston rod. Oilless, characterized by having a grease groove filled with Compressors.

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