JP4331588B2 - Reciprocating compressor - Google Patents

Description

  The present invention relates to a reciprocating compressor suitable for use in, for example, compression of air or refrigerant, a vacuum pump, or the like.

  In general, a reciprocating compressor compresses a gas such as air by rotating a crankshaft by a power source such as a motor and reciprocating a piston in a cylinder (for example, Patent Documents 1 and 2). reference).

Special table 2003-519740 gazette JP-A-49-57208

  A reciprocating compressor according to this type of prior art has a crankcase provided with a plurality of cylinders, and a crankshaft in which an intermediate portion in the axial direction is bent in a crank shape is provided in the crankcase. . Also, the crankcase is provided with two bearing members made of, for example, ball bearings spaced apart in the axial direction of the crankshaft, and these bearing members support the crankshaft so as to be rotatable on both sides in the axial direction. .

  In addition, a plurality of pistons are connected to an intermediate portion in the axial direction of the crankshaft via connecting rods, and these pistons are inserted into the respective cylinders so as to be able to reciprocate. During the operation of the compressor, the crankshaft is driven to rotate around a certain axis, and the rotation is converted into the reciprocating motion of the piston via a connecting rod or the like, so that the piston reciprocates within each cylinder. Gas is compressed.

  By the way, in the prior art mentioned above, it has the structure which supports the axial direction both sides of a crankshaft rotatably with a bearing member, and connects a some piston to the axial direction intermediate part of a crankshaft.

  However, since a large reaction force (load) when the piston compresses gas in each cylinder is applied to the intermediate part of the crankshaft, the intermediate part is bent or damaged by the load from each piston. High strength and rigidity are required.

  Especially when the number of cylinders is increased to improve the performance of the compressor, the connecting parts of each cylinder are mounted side by side in the axial direction, and the middle part of the crankshaft becomes long and the cylinders are arranged. In some cases, the load generated by the plurality of pistons becomes a large resultant force and is applied to the crankshaft.

  For this reason, in the prior art, the intermediate part of the crankshaft must be thickened to ensure strength and rigidity, and the outer diameter and weight of the entire crankshaft tend to be large, which increases the size of the compressor. In addition, there is a problem that a large bearing member is required and the cost is increased. On the other hand, if an attempt is made to avoid an increase in the size of the compressor, the dimensions, strength, etc. of the crankshaft are limited, and there are limits to the increase in the number of cylinders and the performance of the compressor.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to ensure a sufficient strength and rigidity while forming a rotating shaft compactly, and even a compressor having a plurality of cylinders. Another object of the present invention is to provide a reciprocating compressor capable of promoting reduction in size, weight and cost of the entire machine.

  In order to solve the above-described problems, the present invention provides a casing provided with a plurality of cylinders, a rotating shaft disposed in the casing and driven to rotate about a certain axis, and the rotating shaft provided in the casing. A bearing that is rotatably supported, a plurality of pistons that are reciprocally movable in the cylinders, and a plurality of connecting rods that respectively connect the pistons to an axial intermediate portion of the rotating shaft. It is applied to the reciprocating compressor provided.

The feature of the configuration adopted by the invention of claim 1 is that the bearings are provided on both sides in the axial direction of the rotary shaft and support the rotary shaft outside the connecting rod, and an axial intermediate portion of the rotary shaft. And an intermediate bearing that supports a rotating shaft between the connecting rods, and the rotating shaft is positioned at a linear shaft portion that extends linearly around the axis, and an axially intermediate portion of the rotating shaft. A crankshaft is provided on the end side of the linear shaft portion and is eccentric with respect to the axis, and an eccentric bush having an outer peripheral surface eccentric with respect to the axis is fitted on the outer periphery of the linear shaft. A part of the plurality of connecting rods is attached to the outer peripheral surface of the eccentric bush, and the remaining connecting rods are attached to the outer peripheral side of the crankshaft portion via the bush. The crankshaft portion of the rotating shaft and the eccentric bush Shoe and is to have a configuration in which the eccentric with different dimensions with respect to the axis of the rotary shaft.

Further, according to the invention of claim 2, the cylinder, and a low-pressure cylinder for discharging a compressed gas of the intermediate pressure is sucked to the low pressure gas, by a high pressure cylinder for discharging a high-pressure compressed gas sucks the gas in the intermediate pressure configured, the crank shaft portion of the rotating shaft connecting the piston reciprocating within the low-pressure cylinder, the straight shaft portion is configured for connecting the piston reciprocating within the high pressure cylinder.

Further, according to the invention of claim 3, the eccentric bushing is provided a plurality on an outer peripheral side of the rotary shaft, at least a portion of the eccentric bush of the respective eccentric bush is decentered in different directions from the center of rotation of the rotary shaft arrangement It is said.

Furthermore, according to the invention of claim 4, a plurality of intermediate bearings are arranged apart from each other in the axial direction of the rotary shaft.

According to the invention of claim 5 , the intermediate bearing is configured as a non-dividing type bearing that is not divided into a plurality of arcuate bodies.

  According to the first aspect of the present invention, both axial sides of the rotating shaft can be supported by the outer bearings, and the intermediate portion in the axial direction can be supported by the intermediate bearing. For this reason, for example, in the compression stroke of the piston, even if a large radial load is applied from the connecting rod to the rotary shaft, this load can be stably received at three locations in the axial direction, It is possible to reliably prevent the occurrence of bending or damage.

  Thereby, for example, in a multi-cylinder type compressor having four cylinders or more, it is not necessary to increase the diameter of the rotating shaft to give high strength and rigidity, and the shape and structure of the rotating shaft can be simplified and the outer diameter dimension thereof can be simplified. And the weight can be reduced. Therefore, for example, even if the compressor is multi-cylinder and the performance such as discharge pressure is improved, the entire machine can be made compact and lightweight, and small bearing parts can be used as outer bearings and intermediate bearings. Parts cost can be reduced.

Further, the rotation axis, constituted by a straight shaft portion and the crankshaft portion, since the outer peripheral side of the straight shaft portion is attached to the connecting rod part via the eccentric bushing, straight shank of the rotary shaft it is possible to convert the rotation into reciprocation of the piston by the eccentric bushing and the connecting rod. And the linear shaft part of a rotating shaft can be easily processed and formed as a linear rod, and productivity can be improved. Further, when assembling the compressor, components such as an eccentric bush, an outer bearing, and an intermediate bearing can be easily attached to the outer peripheral side of the linear shaft portion by an axial press-fitting operation, and the assembling work can be performed efficiently. .

As a result, it is not necessary to use a split type bearing or the like that is attached to the linear shaft portion of the rotary shaft from the outside in the radial direction in a state where it is divided into a plurality of parts. A grease-enclosed bearing or the like can be used, and an oil-free compressor can be easily realized.

Furthermore, by using the eccentric bush, the stroke of each piston, the phase difference of the reciprocating motion, etc., depending on the shape of the eccentric bush (degree of eccentricity), the mounting position on the linear shaft (position in the rotational direction), etc. It can be set appropriately. In this case, it is possible to prevent the degree of freedom in setting the stroke and phase difference due to the restriction of the shape of the crankshaft as in the prior art, and it is easy to optimize these settings. Or it can abbreviate | omit and can promote size reduction and weight reduction of a compressor. And even in this state, each piston can be reciprocated with good balance, and the vibration and noise of the compressor can be reduced.

Moreover , according to the first aspect of the present invention, a part of the connecting rods can be connected to the linear shaft portion of the rotating shaft via the eccentric bush, and the remaining connecting rods can be connected to the crankshaft portion. . In this case, the linear shaft portion can easily achieve high strength, and the crankshaft portion can be formed with a large eccentricity.

  For this reason, for example, when providing a plurality of types of cylinders having different cross-sectional areas of cylinders, piston strokes, etc., the parts connecting the individual pistons according to the magnitude of the load applied to the rotary shaft, the strokes of the pistons, etc. It can be used properly between the linear shaft portion and the crankshaft portion, and the degree of design freedom can be increased.

According to the invention of claim 1 , the eccentric amount of the eccentric bush with respect to the axis of the rotating shaft and the eccentric amount of the crankshaft portion can be made different. Thereby, the piston connected to the eccentric bush and the piston connected to the crankshaft can be reciprocated with different strokes, and the degree of freedom in design can be increased.

According to the second aspect of the present invention, for example, the low-pressure side piston whose reaction force during compression is small and the stroke is desired to be set can be connected to the crankshaft portion of the rotary shaft, and the high-pressure side reaction force during compression is large. Since the piston can be connected to the linear shaft portion, a two-stage compressor with high compression performance can be easily configured.

According to the invention of claim 3 , each eccentric bush can be rotated around the rotation axis with a phase difference. Therefore, when the pistons connected to the individual eccentric bushes reciprocate, an appropriate phase difference can be given to these reciprocations, and the inertial force and the like generated in each piston can be canceled in a balanced manner.

Further, according to the invention of claim 4 , intermediate shaft bearings can be arranged on the rotating shaft, for example, at the connecting portion of each connecting rod, and the load of each piston is distributed and received by these intermediate bearings and outer bearings. Therefore, the downsizing of the outer bearing and the intermediate bearing can be promoted. Moreover, for example, the pressure of each cylinder can be set high, and the performance of the compressor can be improved.

In addition, according to the invention of claim 5 , as the non-split type intermediate bearing, for example, a grease-enclosed bearing or the like can be used. Therefore, an oil-free compressor having a simple structure can be easily realized.

  Hereinafter, a reciprocating compressor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 to 7 show a first reference example as a premise of the present invention . In the first reference example , a horizontally opposed four-cylinder air compressor will be described as an example.

  Reference numeral 1 denotes a horizontally opposed four-cylinder type air compressor. The air compressor 1 includes a casing 2, a rotating shaft 3, eccentric bushes 4 and 5, compression parts 6, 18, 22, and 26, an outer bearing 30, and an intermediate, which will be described later. It is comprised by the bearing 31 grade | etc.,.

  Reference numeral 2 denotes a substantially box-shaped casing constituting the outer shell of the air compressor 1, and the casing 2 is, for example, a bottomed metal case having an upper side opened and a lower side closed as shown in FIGS. Is formed. Further, substantially cylindrical mounting portions 2A and 2A to which the outer bearings 30 are respectively attached are provided on the peripheral wall of the casing 2 so as to be spaced apart in the axial direction of the rotary shaft 3, and an intermediate bearing 31 is provided at the bottom of the casing 2. A mounting seat 2B to be mounted is projected. Further, the opening side of the casing 2 is closed by a cover plate 2C (see FIG. 2).

  Reference numeral 3 denotes a rotating shaft that is rotatably provided on the casing 2 via, for example, three bearings 30 and 31. The rotating shaft 3 is made of, for example, a cylindrical metal rod as shown in FIG. It extends linearly around -O. Further, the rotary shaft 3 is positioned on both sides in the axial direction and is positioned between the two outer shaft portions 3A to which the inner rings 30B of the outer bearing 30 are respectively fitted, and the casing 2 between the outer shaft portions 3A. The intermediate shaft portion 3 </ b> B disposed inside and the pulley mounting portion 3 </ b> C protruding from the one outer shaft portion 3 </ b> A to the outside of the casing 2.

  In this case, each outer shaft portion 3A and intermediate shaft portion 3B of the rotating shaft 3 are formed to have substantially the same outer diameter. The rotating shaft 3 is rotated about an axis OO when a driving pulley (not shown) is attached to the pulley mounting portion 3C, and the pulley is rotated by a power source such as a motor. Is.

  Reference numeral 4 denotes, for example, two eccentric bushes provided on the intermediate shaft portion 3B of the rotary shaft 3 at positions corresponding to the compression portions 6 and 18, which will be described later. The eccentric bushes 4 are as shown in FIGS. It is formed in a substantially cylindrical shape by a metal material or the like, and is fixed to the outer peripheral side of the intermediate shaft portion 3B in a non-rotating state and rotates integrally with the rotary shaft 3.

  Here, as shown in FIG. 6, the inner peripheral surface of the eccentric bush 4 becomes a circular shaft fitting hole 4 </ b> A that is fitted to the outer periphery of the intermediate shaft portion 3 </ b> B in a non-rotating state by means such as press fitting. The center of the shaft fitting hole 4A is eccentric in the radial direction by a certain dimension δ (eccentricity δ) with respect to the center of the cylindrical outer peripheral surface 4B. Then, a connecting rod 15 of the compression portion 6 described later is rotatably attached to the outer peripheral surface 4B of one eccentric bush 4 via a large end bearing 16, and the outer peripheral surface 4B of the other eccentric bush 4 is A connecting rod 21 of the compression unit 18 is rotatably attached via another large end bearing 16.

  Reference numeral 5 denotes, for example, two eccentric bushes provided on the intermediate shaft portion 3B of the rotary shaft 3 at positions corresponding to the compression portions 22 and 26 described later. Each eccentric bush 5 is a metal having the same shape as the eccentric bush 4, for example. It has a circular shaft fitting hole 5A and an outer peripheral surface 5B which are made of a cylinder or the like and are eccentric by an eccentric amount δ. And the shaft fitting hole 5A of each eccentric bush 5 is being fixed to the outer peripheral side of the intermediate shaft part 3B in the non-rotating state. Further, connecting rods 25 and 29 of the compression portions 22 and 26 are rotatably attached to the outer peripheral surface 5 </ b> B of each eccentric bush 5 via the large end bearing 16.

  Further, the eccentric bush 4 and the eccentric bush 5 are eccentric with respect to the rotation center (axis line OO) of the rotation shaft 3 in the opposite directions in the diametric direction, for example, and the directions of eccentricity with respect to the rotation center are different from each other. Thereby, when the rotating shaft 3 rotates, the eccentric bushes 4 and 5 rotate around the axis line OO with a phase difference of 180 °.

  For this reason, for example, by connecting a pair of pistons 14 and 24 (or pistons 20 and 28) spaced in the diameter direction across the rotating shaft 3 to different eccentric bushes 4 and 5, the pistons 14 and 24 and the pistons 20 and 20 are connected. While reciprocating 28 in the same phase for each group, the reciprocating motion can be performed in the opposite phase between the two groups.

  Reference numeral 6 denotes a first compression portion disposed, for example, on one side in the diametrical direction of the rotating shaft 3 (front side in FIG. 1). The compression portion 6 is constituted by a cylinder 7, a piston 14, a connecting rod 15 and the like which will be described later. It is configured. And the compression part 6 suck | inhales and compresses air from the below-mentioned suction inlet 10, and discharges compressed air from the discharge outlet 11, when the piston 14 reciprocates the inside of the cylinder 7. FIG.

  7 is a cylindrical cylinder erected on the outer surface side of the casing 2. As shown in FIG. 4, a cylinder head 9 is mounted on the cylinder 7 via a valve plate 8, and the cylinder head 9 has a suction port. 10 and a discharge port 11 are provided. The valve plate 8 is provided with a suction valve 12 for communicating and blocking between the inside of the cylinder 7 and the suction port 10 and a discharge valve 13 for communicating and blocking between the inside of the cylinder 7 and the discharge port 11. ing.

  A piston 14 is provided in the cylinder 7 so as to be able to reciprocate. The piston 14 is driven by the rotary shaft 3 via the eccentric bush 4, the connecting rod 15, and the like, and between the top dead center and the bottom dead center. Reciprocates. In this case, the stroke of the piston 14 is set according to the eccentric amount δ of the eccentric bush 4.

  15 is a connecting rod for connecting the piston 14 to the intermediate shaft portion 3B of the rotating shaft 3, and the connecting rod 15 cooperates with the eccentric bush 4 to convert the rotation of the rotating shaft 3 into the reciprocating motion of the piston 14. is there. In this case, as shown in FIG. 5, the connecting rod 15 is a large end portion 15A having a large-diameter cylindrical shape on one end side, and the large end portion 15A is eccentric via a large end bearing 16 such as a ball bearing. The bush 4 is rotatably attached to the outer peripheral surface 4B. Further, the other end side of the connecting rod 15 is a small end portion 15B having a small diameter cylindrical shape, and the small end portion 15B is swingably attached to the piston 14 via a pin 17.

  Next, 18 is a second compression unit disposed on the opposite side of the first compression unit 6 in the diametrical direction (the back side in FIG. 1) across the rotation shaft 3, and the compression unit 18 is a compression unit. Almost the same as the portion 6, the cylinder 19, the piston 20, the connecting rod 21 and the like are configured. In this case, the connecting rod 21 is rotatably attached to the outer peripheral surface 4B of the eccentric bush 4 via the large end bearing 16 and the small end 21B swings to the piston 20 via the pin 17. Installed as possible.

  Reference numeral 22 denotes a third compression portion arranged on the one side in the diameter direction of the rotary shaft 3 along with the first compression portion 6, and the compression portion 22 includes a cylinder 23, a piston 24, a connecting rod 25, and the like. Yes. The connecting rod 25 has a large end 25A rotatably attached to the outer peripheral surface 5B of the eccentric bush 5 via the large end bearing 16, and a small end 25B swingable to the piston 24 via the pin 17. Installed on.

  Furthermore, 26 is a fourth compression part arranged on the other side in the diameter direction of the rotary shaft 3 along with the second compression part 18, and the compression part 26 is constituted by a cylinder 27, a piston 28, a connecting rod 29 and the like. The connecting rod 29 has a large end 29A rotatably attached to the outer peripheral surface 5B of the eccentric bush 5 via the large end bearing 16, and a small end 29B swinging to the piston 28 via the pin 17. Installed as possible.

  And in these four compression parts 6, 18, 22, and 26, when the rotating shaft 3 rotates, the pistons 14 and 24 and the pistons 20 and 28 reciprocate in the same phase, respectively. 24 and the pistons 20 and 28 reciprocate in opposite phases.

  In this case, the pistons 14 and 24 are disposed at substantially target positions in the axial direction around an intermediate bearing 31 described later, and the pistons 20 and 28 are also disposed at substantially target positions with respect to each other. The pistons 14 and 24 and the pistons 20 and 28 are arranged so as to intersect with each other. Thereby, during operation of the compressor, the load applied to the rotary shaft 3 between the pistons 14 and 24 and between the pistons 20 and 28 can be canceled, and the inertial force generated in the compression parts 6, 18, 22, and 26. The (moment of inertia) can be canceled in a well-balanced manner, and the vibration and noise of the compressor 1 can be reduced.

  Reference numeral 30 denotes, for example, two outer bearings provided in each mounting portion 2A of the casing 2, and each outer bearing 30 includes a non-divided bearing that is not divided into a plurality of arcuate bodies. An encapsulated deep groove ball bearing or the like is used. 2 and 3, these outer bearings 30 are respectively disposed on both sides in the axial direction of the rotating shaft 3 and rotate the rotating shaft 3 outside the connecting rods 15, 21, 25, 29. It is possible to support.

  Here, the outer bearing 30 is fitted by an outer ring 30A fitted in the mounting portion 2A and an outer peripheral side of the outer shaft portion 3A of the rotating shaft 3 by means such as press fitting, which is located on the inner peripheral side of the outer ring 30A. The inner ring 30B is combined with the outer ring 30A and the inner ring 30B, and a plurality of steel balls 30C are rotatably connected. Further, a lubricant (not shown) such as grease is enclosed between the outer ring 30A and the inner ring 30B.

31 is an intermediate bearing provided on the mounting seat portion 2B of the casing 2, and the intermediate bearing 31 is a non-divided bearing that is not divided into a plurality of arcuate bodies (ie, ball bearings, roller bearings, etc.). In the first reference example , for example, a grease-enclosed deep groove ball bearing or the like is used, and the outer diameter shape is a cylindrical shape and cannot be divided into a plurality of semicircular arcs in the radial direction. It is comprised using. The intermediate bearing 31 is positioned between the connecting rods 15, 21 and the connecting rods 25, 29 and rotatably supports the intermediate shaft portion 3 </ b> B of the rotating shaft 3.

  In this case, the intermediate bearing 31 is positioned on the inner peripheral side of the outer ring 31B, the support part 31A attached to the attachment seat part 2B by means such as screwing, the outer ring 31B fitted to the support part 31A, and the like. The inner ring 31C fitted to the outer peripheral side of the intermediate shaft portion 3B of the rotary shaft 3 by means such as press fitting, and a plurality of steel balls 31D for rotatably connecting the outer ring 31B and the inner ring 31C, etc. .

  The intermediate bearing 31 has a radial direction applied to the intermediate shaft portion 3B of the rotary shaft 3 via the connecting rods 15, 21, 25, 29, etc., when the pistons 14, 20, 24, 28 perform a compression stroke. A reaction force (load) is received, and this load prevents the intermediate shaft portion 3B from being bent and damaged.

On the other hand, in FIG. 7, 32 is an air tank to which the discharge ports 11 of the compression units 6, 18, 22, and 26 are connected, and the air compressor 1 according to the first reference example is, for example, a 4-cylinder 1-stage compressor. It is configured as.

The air compressor 1 according to the first reference example as the premise of the present invention has the above-described configuration, and the operation thereof will be described next.

  First, at the time of assembling the compressor, as shown in FIG. 6, after forming the linear rotary shaft 3, components such as the eccentric bushes 4, 5, the outer bearings 30, the intermediate bearing 31, etc. Press-fit in the axial direction from the side and attach these parts in place.

  In this case, by using the eccentric bushes 4 and 5, the rotating shaft 3 can be easily processed and formed as a linear rod, and productivity can be increased. Further, parts such as the eccentric bushes 4 and 5 and the bearings 30 and 31 can be easily attached to the outer peripheral side of the rotating shaft 3 by the axial press-fitting operation, and the assembling work can be performed efficiently.

  As a result, it is not necessary to use a split bearing or the like that is attached to the rotary shaft 3 from the outside in the radial direction in a state where the intermediate bearing 31 is divided into a plurality of parts, and can be divided into a plurality of arcuate bodies. Non-split bearings can be used. Further, since non-split type bearings can also be used for the outer bearing 30, grease-sealed bearings or the like can be used as these bearings 30, 31, and the oil-free air compressor 1 can be easily realized. Can do.

  Next, when the compressor is operated, first, when the rotary shaft 3 is rotationally driven by a drive source such as a motor, the rotational movement of the eccentric bushes 4 and 5 rotating together with the rotary shaft 3 is caused to be connected to the connecting rods 15, 21, 25 and 25. 29 is converted into reciprocating motion of the pistons 14, 20, 24, 28, and the pistons reciprocate in the cylinders 7, 19, 23, 27, respectively.

  Thereby, in the suction stroke of each compression part 6,18,22,26, when the suction valve 12 opens and the discharge valve 13 closes, air is suck | inhaled from the suction inlet 10 in a cylinder. In the compression stroke, the suction valve 12 is closed, the air in the cylinder is compressed, and the discharge valve 13 is opened near the top dead center, so that the compressed air in the cylinder is discharged from the discharge port 11 to the air tank 32. It is discharged toward.

  In this case, the eccentric bushes 4 and 5 are attached to the rotary shaft 3 with a phase difference of 180 °. For this reason, in one set of compression parts 6 and 22 (or compression parts 18 and 26) located on both sides in the diameter direction of the rotating shaft 3, the suction stroke and the compression stroke are performed in the same phase for each set. Each stroke can be performed in antiphase between the two sets. Thereby, the load added to the rotating shaft 3 between the pistons 14 and 24 and between the pistons 20 and 28 can be canceled.

  In addition, the load applied to the intermediate shaft portion 3B of the rotary shaft 3 can be stably received at three locations in the axial direction by the respective outer bearings 30 and the intermediate bearings 31. As a result, the intermediate shaft portion 3B is bent, damaged or the like. It can be surely prevented from occurring.

  In addition, one pair of connecting rods 15 and 21 (or connecting rods 25 and 29) operate in opposite phases to each other so that one connecting rod is connected to the other connecting rod in each pair of connecting rods. It can act as a counterweight. Thereby, the inertia force which arises in each compression part 6,18,22,26 can be canceled with sufficient balance, and the vibration of the compressor 1, a noise, etc. can be reduced.

Thus, according to the first reference example which is a premise of the present invention, the outer bearings 30 are provided on both sides in the axial direction of the rotary shaft 3 and the intermediate bearing 31 is provided on the intermediate shaft portion 3B. The bearings 30 and 31 can stably support the rotary shaft 3 at three locations in the axial direction. For example, even if a large radial load is applied to the intermediate shaft portion 3B, the intermediate bearing 31 can reliably Can be accepted.

  As a result, even in a multi-cylinder compressor having four or more cylinders, for example, it is not necessary to increase the diameter of the rotating shaft 3 to give high strength and rigidity. For example, the rotating shaft 3 can be formed as a small-diameter linear rod. The shape and structure can be simplified to reduce the weight. Therefore, for example, even if the compressor 1 is made multi-cylinder and the performance such as discharge pressure is improved, the entire machine can be made compact and lightweight, and small bearing parts can be used as the outer bearing 30 and the intermediate bearing 31. This can reduce the cost of parts.

  Further, since the rotating shaft 3 is formed in a straight line and the eccentric bushes 4 and 5 having a phase difference of 180 ° are attached, for example, depending on the eccentric amount δ of the eccentric bushes 4 and 5, the mounting position in the rotation direction, etc. The stroke of each piston 14, 20, 24, 28, the phase difference of reciprocation, etc. can be set appropriately, and each piston can be reciprocated with good balance. In this case, it is possible to prevent the degree of freedom in setting the stroke and phase difference due to the restriction of the shape of the crankshaft as in the prior art, and it is easy to optimize these settings. Alternatively, the compressor 1 with low vibration and noise can be easily realized even in this state.

Next, FIGS. 8 to 10 show a first embodiment according to the present invention . The feature of the first embodiment is that a two-stage compressor having a rotary shaft formed of a linear shaft portion and a crankshaft portion and having two low-pressure and high-pressure cylinders is provided. In this embodiment, the same reference numerals to the same components as in the first reference example shown in FIGS. 1 to 7 were pre-mentioned, the description thereof is omitted.

Reference numeral 41 denotes a horizontally opposed four-cylinder type air compressor. The air compressor 41 is substantially similar to the first reference example described above, and includes a casing 2, an eccentric bush 5, each outer bearing 30, an intermediate bearing 31, and a later-described air compressor. The rotary shaft 42 and the compression units 44, 48, 51, and 55 are generally configured as a two-stage compressor.

Reference numeral 42 denotes a rotating shaft that is rotatably provided on the casing 2 via, for example, three bearings 30 and 31. The rotating shaft 42 is centered on the axis OO in substantially the same manner as in the first reference example described above. Are driven to rotate.

  Here, the rotating shaft 42 is located on both sides in the axial direction, and is provided with two outer shaft portions 42A to which the inner rings 30B of the outer bearing 30 are respectively fitted, and one outer shaft portion of the outer shaft portions 42A. A linear shaft portion 42B formed linearly extending from the outer shaft portion 42 to the casing 2, a crankshaft portion 42C bent into a crank shape from the other outer shaft portion 42A and extended into the casing 2, a linear shaft portion 42B and a crank The plate-shaped counterweight 42D is provided so as to be connected to the shaft portion 42C, and the pulley mounting portion 42E protrudes outside the casing 2 from the other outer shaft portion 42A.

  In this case, as shown in FIG. 8, in the rotating shaft 42, the outer shaft portions 42A are arranged coaxially with each other about the axis OO. Further, the linear shaft portion 42B is formed in a cylindrical shape with the axis OO as the center, and the eccentric bush 5 is attached to the outer peripheral side thereof in a non-rotating state.

  Further, the intermediate bearing 31 is arranged at a position near the counterweight 42D in the linear shaft portion 42B. The intermediate bearing 31 is disposed between the low pressure side compression portions 44 and 48 (connecting rods 47 and 50) and the high pressure side compression portions 51 and 55 (connecting rods 54 and 57), which will be described later. The linear shaft portion 42B is rotatably supported by the intermediate portion in the axial direction.

  On the other hand, the center of the crankshaft portion 42C is eccentric in the radial direction by an eccentric amount δ ′ with respect to the axis OO. The eccentric amount δ ′ is formed in a dimension different from the eccentric amount δ of the eccentric bush 5 and is set to a dimension larger than the eccentric amount δ (δ ′> δ), for example. Further, on the outer peripheral side of the crankshaft portion 42C, for example, a cylindrical bush 43 having no eccentric portion is fitted. Further, the counterweight 42D balances the inertial force generated by the compression units 44, 48, 51, and 55 described later.

Reference numeral 44 denotes a low-pressure side compression section constituting the two-stage air compressor 41. The compression section 44 is composed of a cylinder 45, a piston 46, a connecting rod 47, etc., as in the first reference example described above. Has been.

  Here, as shown in FIG. 10, the compression unit 44 sucks and compresses low-pressure air from the suction port 10 into the cylinder 45 and compresses intermediate-pressure compressed air from the discharge port 11 toward the compression unit 51 on the high-pressure side. The cylinder 45 constitutes a low-pressure cylinder of a two-stage compressor (hereinafter referred to as a low-pressure cylinder 45). Further, the large end portion 47 </ b> A of the connecting rod 47 is rotatably attached to the crankshaft portion 42 </ b> C of the rotary shaft 42 via the large end bearing 16 and the bush 43.

  Reference numeral 48 denotes a low-pressure side compression portion disposed on the opposite side of the diametrical direction with respect to the compression portion 44 with the rotation shaft 42 interposed therebetween. 1), the connecting rod 50 and the like, and the large end 50A of the connecting rod 50 is rotatably attached to the crankshaft portion 42C of the rotating shaft 42.

  These low pressure side compression portions 44 and 48 are driven by the crankshaft portion 42C of the rotating shaft 42, and the piston 46 and the like reciprocate with a stroke corresponding to the eccentric amount δ 'of the crankshaft portion 42C.

  On the other hand, 51 is a high-pressure side compression part arranged on the one side in the diameter direction of the rotating shaft 42 along with the low-pressure side compression part 44. The compression part 51 has an intermediate pressure compressed by the low-pressure side compression part 44. Compressed air is sucked from the suction port 10 and compressed, and high-pressure compressed air is discharged from the discharge port 11 toward the air tank 32. The compressed air is composed of a high-pressure cylinder 52, a piston 53, a connecting rod 54, and the like.

  Reference numeral 55 denotes a high-pressure side compression portion disposed on the opposite side of the diametrical direction from the compression portion 51 with the rotation shaft 42 interposed therebetween. The compression portion 55 is similarly connected to a high-pressure cylinder 56, a piston (not shown), and a connection. It is composed of a rod 57 and the like.

  The high pressure side compression portions 51 and 55 are attached to the outer peripheral surface 5B of the eccentric bush 5 via the large end bearings 16 so that the large end portions 54A and 57A of the connecting rods 54 and 57 are rotatable. Thereby, the compression parts 51 and 55 are driven by the linear shaft part 42B of the rotating shaft 42 via the eccentric bush 5 or the like, and the piston 53 or the like reciprocates with a stroke corresponding to the eccentric amount δ of the eccentric bush 5. .

Thus, in this way, the first embodiment constructed, can be a first reference example before mentioned obtain substantially the same operational effects. In particular, in the first embodiment, since the linear shaft portion 42B and the crankshaft portion 42C are formed on the rotating shaft 42, for example, the linear shaft portion 42B can easily realize high strength, and the crankshaft portion 42C The eccentric amount δ ′ larger than the eccentric amount δ of the eccentric bush 5 can be provided.

  Thereby, for example, the low pressure side compression parts 44 and 48 for which the reaction force in the compression stroke is small and the stroke is set to be large can be connected to the crankshaft portion 42C, and the high pressure side compression part 51, which has a large reaction force in the compression stroke. 55 can be connected to the linear shaft portion 42B.

  Therefore, for example, the cylinder diameter, the stroke of the piston, etc. can be made different between the low pressure side compression parts 44, 48 and the high pressure side compression parts 51, 55, increasing the degree of freedom in design and having a high compression performance. The compressor can be easily configured.

Next, FIGS. 11 and 12 show a second embodiment according to the present invention, features of the second embodiment, that low-pressure side pressure side constituted the two-stage compressor of one cylinder with three cylinders is there. In this embodiment, the same reference numerals to the same components as in the first reference example before mentioned, and description thereof is omitted.

61 is a two-stage compression type air compressor, and the air compressor 61 is similar to the first embodiment in that the casing 2, the rotary shaft 62, each outer bearing 30, the intermediate bearing 31, The compression unit 64, 65, 66, 70 is generally configured.

  The rotating shaft 62 includes outer shaft portions 62A, linear shaft portions 62B, a crankshaft portion 62C, a counterweight 62D, a pulley mounting portion 62E, and the like. The crankshaft portion 62C is eccentric from the axis OO of the rotating shaft 62 by an eccentric amount δ ′, and a cylindrical bush 63 is provided on the outer peripheral side thereof.

  Reference numerals 64, 65, and 66 denote, for example, three-cylinder low-pressure side compression sections. The compression sections 64, 65, and 66 suck low-pressure air from the suction port 10 and compress it in the same manner as in the second embodiment. Then, compressed air with an intermediate pressure is discharged from the discharge port 11 toward the compression unit 70 on the high pressure side.

  The compression portion 64 includes a low-pressure cylinder 67, a piston 68, a connecting rod 69, and the like. The large end portion 69A of the connecting rod 69 is connected to the crank shaft portion 62C of the rotating shaft 62, the bush 63, the large end bearing 16 and the like. It is attached to be rotatable. Similarly, the compression parts 65 and 66 are constituted by a low-pressure cylinder 67, a piston 68, a connecting rod 69, and the like, respectively.

  On the other hand, reference numeral 70 denotes a high pressure side compression section composed of, for example, one cylinder. As shown in FIG. 12, the compression section 70 has the suction ports 10 connected to the discharge ports 11 of the compression portions 64 to 66 in parallel. The compressed air of intermediate pressure compressed by the compression units 64 to 66 is sucked from the suction port 10 and compressed, and high-pressure compressed air is discharged from the discharge port 11 toward the air tank 33. The compression unit 70 is configured by a high-pressure cylinder 71, a piston 72, a connecting rod 73, and the like in substantially the same manner as in the second embodiment, and the large end 73A of the connecting rod 73 is interposed via the large end bearing 16. The eccentric bush 5 is rotatably attached to the outer peripheral surface 5B.

Thus, even in thus configured present embodiment, it is possible to the first embodiment described before mentioned obtain substantially the same operational effects. In particular, in the second embodiment, the low pressure side is constituted by the compression portions 64, 65, 66 of three cylinders, and the high pressure side is constituted by the compression portion 70 of one cylinder, so that variations of the two-stage compressor are increased. Design freedom.

Next, FIG. 13 shows the second reference example, features of the second reference example is to have a configuration in which a plurality of intermediate bearing in the middle portion of the rotary shaft. In this embodiment, the same reference numerals to the same components as in the first reference example before mentioned, and description thereof is omitted.

81 is a horizontally opposed four-cylinder air compressor, air compressor 81 is substantially similar to the first reference example before mentioned, the casing 82, the rotary shaft 83, the compression unit 6,18,22,26, Each outer bearing 30 and each intermediate bearing 31 are roughly configured.

  Further, substantially cylindrical mounting portions 82 </ b> A and 82 </ b> A to which the respective outer bearings 30 are mounted are provided on the peripheral wall of the casing 82 so as to be separated in the axial direction of the rotary shaft 83. Further, for example, three mounting seats 82B are provided at intervals in the axial direction at the bottom of the casing 82, and the intermediate bearings 31 are respectively attached to these mounting seats 82B.

Further, the rotation shaft 83 is formed as a linear rod extending along the axis OO in substantially the same manner as the first reference example described above, and is formed by the outer shaft portion 83A, the intermediate shaft portion 83B and the pulley mounting portion 83C. It is configured.

  The rotating shaft 83 has outer shaft portions 83A on both sides in the axial direction supported rotatably by the respective outer bearings 30, and the intermediate shaft portion 83B supported rotatably by the three intermediate bearings 31. In this case, the intermediate bearing 31 is disposed between the connecting rods 15, 21, 25, 29 of the compression parts 6, 18, 22, 26, respectively.

Next, FIGS. 14 to 16 show the third reference example, features of the third reference example is that it is applied to an air compressor of V-type 4-cylinder.

Reference numeral 91 denotes a V-type four-cylinder air compressor. The air compressor 91 extends in a straight line along a substantially box-shaped casing 92 and an axis OO in substantially the same manner as the first reference example described above. The rotating shaft 93, eccentric bushes 94 and 95, compression parts 96, 97, 104, and 105, which will be described later, an outer bearing 107, an intermediate bearing 108, and the like are included.

  The casing 92 is provided with a plurality of mounting seats 92A (only one is shown) to which the outer bearing 107 and the intermediate bearing 108 are mounted. Further, as shown in FIG. 15, the rotating shaft 93 is constituted by each outer shaft portion 93A, an intermediate shaft portion 93B, and a pulley mounting portion 93C.

Further, two eccentric bushes 94 and 95 are provided on the intermediate shaft portion 93B of the rotating shaft 93 in the same manner as in the first reference example described above, and the shaft on which the intermediate shaft portion 93B is fitted in a non-rotating state. It has fitting holes 94A and 95A and outer peripheral surfaces 94B and 95B that are eccentric with respect to the shaft fitting holes 94A and 95A by an eccentric amount δ (see FIG. 16). In this case, the eccentric bushes 94 and 95 are eccentric with respect to the rotation center (axis OO) of the rotation shaft 93 in the diametrically opposite directions, and are disposed with a phase difference of 180 °.

  Reference numerals 96 and 97 denote compression parts constituting two cylinders of the four cylinders of the air compressor 91. As shown in FIGS. 14 and 15, these compression parts 96 and 97 are substantially V-shaped as a whole. The cylinders 98, pistons 99, connecting rods 100, etc. are arranged at an angle.

A cylinder head 102 is mounted on the cylinder 98 via a valve plate 101 in substantially the same manner as in the first reference example described above . Further, the connecting rod 100 has a large end portion 100 </ b> A rotatably attached to the outer peripheral surface 94 </ b> B of the eccentric bush 94 via the large end portion bearing 103, and a small end portion 100 </ b> B attached to the piston 99.

  Next, reference numerals 104 and 105 denote compression parts constituting the other two cylinders of the air compressor 91. These compression parts 104 and 105 are substantially the same as the compression parts 96 and 97 as shown in FIG. They are arranged so as to be inclined in a V shape, and are each composed of a cylinder, a piston (both not shown), a connecting rod 106 and the like.

  The connecting rod 106 has a large end portion 106A rotatably attached to the outer peripheral surface 95B of the eccentric bush 95 via the large end portion bearing 103, and a small end portion 106B attached to the piston.

Reference numeral 107 denotes two outer bearings provided on the mounting seat portion 92A of the casing 92. Each of the outer bearings 107 has, for example, substantially the same configuration as that of the intermediate bearing 31 of the first reference example described above, as shown in FIG. And is mounted on the outer peripheral side of the outer shaft portion 93A on the both sides in the axial direction of the rotating shaft 93, and rotatably supports the rotating shaft 93 outside the connecting rods 100 and 106. Is.

Reference numeral 108 denotes an intermediate bearing provided on the mounting seat 92A of the casing 92 by means such as screwing, for example. The intermediate bearing 108 is substantially the same as the first reference example described above, as shown in FIGS. For example, it consists of a ball bearing etc., and it is located between the connecting rods 100 and 106, and supports the intermediate shaft part 93B of the rotating shaft 93 rotatably.

Incidentally, the first, in the second embodiment, the outer bearing 3 0 were set to intermediate bearing 3 1 a structure using a ball bearing. However, the present invention is not limited to this. For example, a roller bearing or a sleeve bearing may be used as these bearings.

In the first and second embodiments, the eccentric amounts δ of the eccentric bushes 4 and 5 are set to be equal. However, the present invention is not limited to this, for example , the eccentric amount of the eccentric bush 4 and the eccentric amount of the eccentric bush 5 are set to different sizes, or the eccentric amount of the eccentric bush for each individual compression unit as necessary. It is good also as a structure which makes different.

In the first and second embodiments, the eccentric amount δ ′ of the crankshaft portions 42C, 62C of the rotating shafts 42, 62 is set larger than the eccentric amount δ of the eccentric bush 5. However, the invention is rather limited thereto, may set both magnitude relation is reversed.

Further, in the first and second embodiments, the connecting rod 47, the cylindrical bushes 43, 63 and the large end bearing 16 are provided on the outer peripheral side of the crankshaft portions 42 C, 62 C of the rotary shafts 42, 62. 50, 69 were attached. However, in the present invention, the bushes 43 and 63 may be omitted, and the connecting rod may be attached to the outer peripheral side of the crankshaft portions 42C and 62C only through the large end bearing.

  On the other hand, in the embodiment, the piston 14 and the connecting rod 15 are connected by the pin 17 or the like. However, the present invention may be applied to a compressor having a swinging piston (locking piston) in which a piston and a connecting rod are integrally formed or fixedly connected to each other.

In the embodiment, the air compressor 4 1,6 1 horizontally opposed four-cylinder or V-type 4-cylinder as a reciprocating compressor is described as an example. However, the present invention is not limited to this. For example, a reciprocating compressor having two cylinders, three cylinders, or five cylinders or more, and a series reciprocating compressor in which each cylinder is arranged in series on one side in the radial direction of the rotating shaft. You may apply to. Furthermore, the present invention can be applied to various compressors that compress a gas other than air including a refrigerant.

1 is a perspective view showing a horizontally opposed four-cylinder air compressor according to a first reference example as a premise of the present invention. FIG. It is the longitudinal cross-sectional view which looked at the air compressor from the arrow II-II direction in FIG. It is the cross-sectional view which looked at the air compressor from the arrow III-III direction in FIG. It is a perspective view which shows the casing of an air compressor alone. FIG. 2 is an enlarged perspective view showing a state in which a rotating shaft, an eccentric bush, a piston, a connecting rod, an outer bearing, an intermediate bearing and the like in FIG. 1 are removed from a casing. It is a cross-sectional view which shows the state before attaching an eccentric bush and each bearing to a rotating shaft. It is a block diagram which shows the connection state of each compression part which performs 4-cylinder 1 stage compression, and an air tank. 1 is a cross-sectional view showing a horizontally opposed four-cylinder air compressor according to a first embodiment of the present invention. It is a cross-sectional view which shows the state before attaching an eccentric bush and each bearing to a rotating shaft. It is a block diagram which shows the connection state of each compression part which performs 4-cylinder two-stage compression, and an air tank. It is a cross-sectional view showing a horizontally opposed four-cylinder type air compressor according to a second embodiment of the present invention. It is a block diagram which shows the connection state of each compression part which performs 4-cylinder two-stage compression, and an air tank. It is a cross-sectional view showing a horizontally opposed 4-cylinder type air compressor according to a second reference example . It is sectional drawing which shows the V type 4 cylinder air compressor by the 3rd reference example . FIG. 15 is an enlarged perspective view showing a state in which a rotating shaft, an eccentric bush, a connecting rod, an outer bearing, an intermediate bearing, and the like in FIG. 14 are removed from the casing. It is an expansion perspective view which shows the phase difference of eccentric bushing.

Explanation of symbols

1,41,61,81,91 Air compressor (reciprocating compressor)
2,82,92 Casing 3,42,62,83,93 Rotating shaft 3B, 83B, 93B Intermediate shaft 4, 5, 94, 95 Eccentric bush 4A, 5A, 94A, 95A Shaft fitting hole 4B, 5B, 94B , 95B Outer peripheral surface 6, 18, 22, 26, 44, 48, 51, 55, 64, 65, 66, 70, 96, 97, 104, 105 Compression section 7, 19, 23, 27, 98 Cylinder 14, 20 24, 28, 46, 53, 68, 72, 99 Piston 15, 21, 25, 29, 47, 50, 54, 57, 69, 73, 100, 106 Connecting rod 30, 107 Outer bearing 31, 108 Intermediate bearing 42B, 62B Linear shaft portion 42C, 62C Crank shaft portion 45, 49, 67 Low pressure cylinder 52, 56, 71 High pressure cylinder

Claims (5)

A casing provided with a plurality of cylinders, a rotating shaft disposed in the casing and driven to rotate about a fixed axis, a bearing provided in the casing and rotatably supporting the rotating shaft, A reciprocating compressor comprising: a plurality of pistons provided so as to be reciprocally movable; and a plurality of connecting rods respectively connecting the pistons to an axially intermediate portion of the rotating shaft.
The bearings are respectively provided on both axial sides of the rotary shaft and support the rotary shaft outside the connecting rod, and between the connecting rods provided at the axial intermediate portion of the rotary shaft and the rotating rod. Comprising an intermediate bearing that supports the shaft,
The rotating shaft includes a linear shaft portion that extends linearly around the axis, and a crankshaft that is provided on an end side of the linear shaft portion that is located in an axially intermediate portion of the rotating shaft and is eccentric with respect to the axis. And consists of
On the outer peripheral side of the linear shaft portion, an eccentric bush having an outer peripheral surface eccentric with respect to the axis is fitted and provided,
A part of the plurality of connecting rods is attached to the outer peripheral surface of the eccentric bush,
The outer peripheral side of the crankshaft portion is configured to attach the remaining connecting rod via a bush ,
The reciprocating compressor characterized in that the crankshaft portion of the rotating shaft and the eccentric bushing are eccentric with different dimensions relative to the axis of the rotating shaft . The cylinder includes a low pressure cylinder that sucks low pressure gas and discharges compressed gas of intermediate pressure, and a high pressure cylinder that sucks gas of intermediate pressure and discharges high pressure compressed gas, and the crankshaft of the rotating shaft The reciprocating compressor according to claim 1, wherein a piston that reciprocates in the low pressure cylinder is connected to the portion, and a piston that reciprocates in the high pressure cylinder is connected to the linear shaft portion. The eccentric bushing is provided a plurality on an outer peripheral side of the rotary shaft, to claim 1 or 2, at least part of the eccentric bushing is a structure to be eccentric in different directions from the center of rotation of the rotary shaft of the respective eccentric bushing The reciprocating compressor described. The reciprocating compressor according to claim 1, 2 or 3 , wherein a plurality of the intermediate bearings are spaced apart in the axial direction of the rotary shaft. 5. The reciprocating compressor according to claim 1, 2, 3, or 4 , wherein the intermediate bearing is configured as a non-dividing bearing that is not divided into a plurality of arcuate bodies.

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