JP2017066896A - Compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor capable of increasing noise even if a ring is worn.SOLUTION: A compressor is equipped with: a drive shaft driven by a motor to be rotated; a first cylinder and a second cylinder oppositely provided; a connecting rod connected with the drive shaft to be rocked; and a piston connected to the connecting rod, and reciprocating in the first cylinder and the second cylinder. The piston is provided with a lip ring sealing a space between the piston, the first cylinder or the second cylinder. Inclined angles to an axial direction of the drive shaft and to a horizontal direction of a reciprocating direction of the piston are within the maximum rocking angle of the connecting rod. The piston sets a rotary direction of the drive shaft so as to be pressed in a gravity direction in the first cylinder or the second cylinder, in compression strokes respectively compressing a fluid in the first cylinder and a fluid in the second cylinder.SELECTED DRAWING: Figure 10A

Description

  The present invention relates to a compressor body structure of a compressor.

  Patent Document 1 describes an integrated piston for a compressor in which a compression portion on a low pressure side and a high pressure side are integrally molded and a small end portion is provided on a low pressure side.

US Patent Application Publication No. 2005/0238513

  In order to reduce the size of the product as a whole, the compression part is arranged so that the compression direction is horizontal, and in order to reduce the weight, as shown in Patent Document 1, two conventional connecting rods are combined into one. A compressor body that performs two-stage compression with a connecting rod was constructed. In this case, if the low pressure lip ring or rider ring attached to the piston is worn due to the operation of the compressor, during the high pressure compression process (low pressure suction process), there is a gap between the cylinder and the ring due to wear. We found a problem that the compression part on the low pressure side in a certain state hits the cylinder and generates noise.

  An object of the present invention is to solve this problem and to provide a compressor capable of preventing an increase in noise even when a ring is worn.

In order to solve the above problems, for example, the configuration of the claims is adopted.
The present application includes a plurality of means for solving the above-described problems. If an example of the compressor of the present invention is given, a drive shaft driven by a motor and rotationally moved, a first cylinder provided oppositely, and A second cylinder, a connecting rod connected to the drive shaft and oscillating, and a piston connected to the connecting rod and reciprocating in the first cylinder and the second cylinder; The piston is provided with a lip ring that seals between the piston and the first cylinder or the second cylinder, and the inclination angle with respect to the horizontal direction of the axial direction of the drive shaft and the reciprocating direction of the piston is The first cylinder is within a maximum swing angle of the connecting rod, and the piston is compressed during the compression step of compressing the fluid in the first cylinder and the second cylinder, respectively. Or it is characterized in that setting the direction of rotation of the drive shaft so as to be pressed against the direction of gravity within the second cylinder.

  As another example of the compressor of the present invention, a crankshaft driven by a motor and rotating, a low pressure side first cylinder and a high pressure side second cylinder provided in opposition to each other, A connecting rod which is connected to the crankshaft and swings, and a piston which is connected to the connecting rod and reciprocates in the first cylinder and the second cylinder. A lip ring that seals between the piston and the first cylinder or the second cylinder is provided, and an inclination angle of the piston in a reciprocating direction with respect to a bottom surface of the compressor is within a maximum swing angle of the connecting rod. The piston is placed in the first cylinder during the compression step of compressing the fluid in the second cylinder and in the suction step of sucking the fluid into the first cylinder. It is characterized in that setting the direction of rotation of the crankshaft so as to be pressed against the direction of gravity.

  According to the present invention, both the low-pressure side compression part and the high-pressure side compression part are always pressed in the direction of gravity during the compression process, so that the integral piston is weighted when switching between the low-pressure side compression process and the high-pressure side compression process. Will not move in the cylinder. Therefore, it is possible to prevent the noise from increasing even if the ring is worn.

  Moreover, since the temperature of the low pressure side compression part is low in the high pressure side compression part and the low pressure side compression part, the burden on the small end part bearing is reduced and the life is extended by providing the small end part in the low pressure side compression part. be able to.

Sectional drawing of the compressor main body of Example 1 which concerns on this invention. The top view of the compressor main body of Example 1 which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. The figure which shows operation | movement of a general piston type compressor. The figure which shows the change of the load F2 of a general piston type compressor. The figure which shows the low voltage | pressure side compression process in an integral piston. The figure which shows the high voltage | pressure side compression process in an integral side piston. The figure which shows the change of the load F2 in the integrated piston of FIG. The front view and sectional drawing of an integrated piston of Example 1 which concern on this invention. The figure which shows the high voltage | pressure side compression process in the integral side piston of Example 1 which concerns on this invention. The figure which shows the low voltage | pressure side compression process in the integral side piston of Example 1 which concerns on this invention. The figure which shows the high voltage | pressure side compression process in other arrangement | positioning of the integral side piston of Example 1 which concerns on this invention. The figure which shows the change of the load F2 in the integral side piston of Example 1 which concerns on this invention.

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

  Up to now, high pressure, miniaturization, and weight reduction have been promoted in order to improve workability and reduce the work load in a portable compressor used for an air tool or a painter. In increasing the pressure, it is difficult to achieve a pressure higher than the current pressure due to legal restrictions. Therefore, in the future, the need for improving workability by further reducing the size and weight may increase. Therefore, in order to meet the needs for further miniaturization and weight reduction, two connecting rods are provided with two compression parts in contrast to the conventional structure in which two connecting rods are arranged and two-stage compression is performed. The structure to perform compression was examined.

First, a compressor body structure according to a first embodiment of the present invention in which two connecting portions are provided on one connecting rod to perform two-stage compression will be described with reference to FIGS.
Reference numeral 1 denotes a compressor body that compresses air or the like. The compressor body 1 includes a crankcase 2 and cylinders 3 and 4 attached to the crankcase 2. A crankshaft 6 rotating through the operation of the motor 5 passes through the crankcase 2. A stator 7 and a main bearing 8 are directly fixed to one end side of the crankcase 2. In addition, a bearing box 9 fitted with a main bearing 8 is fitted on the side opposite to the stator 7 mounting side.

  A crankshaft 6 penetrating the crankcase 2 is formed of cast iron or the like, and a balance for reducing vibration generated by the operation of the compressor body 1 is integrated. A connecting rod 11 with a large end bearing 10 is inserted into the crankshaft 6, and the crankshaft 6 is supported from both ends by two main bearings 8 attached to the crankcase 2 and the bearing box 9. . The rotation shaft center of the large end bearing 10 mounting portion and the rotation shaft center of the main bearing 8 are designed to be different, and the connecting rod 11 performs an eccentric motion by the rotation of the crankshaft 6 by the operation of the motor 5. The amount of eccentricity is determined by the amount of offset between the rotation axis center of the large end bearing 10 and the rotation axis center of the main bearing 8. The eccentric motion of the connecting rod 11 may be a structure using the crankshaft 6 shown in the present embodiment or a structure using eccentric parts as separate members.

  A motor 5 drives the compressor body 1. The motor 5 has a stator 7 and a rotor 12, and the rotor 12 is mounted on the crankshaft 6 through a key. The rotor 12 is fixed in the axial direction by a fan shaft 14 and a washer 15 for fixing the cooling fan 13.

  Reference numeral 13 denotes a cooling fan for cooling components of the air compressor such as the stator 7, the cylinders 3 and 4, and the cylinder heads 16 and 17. The cooling fan 13 is rotated by driving the motor 5 to cool each part.

  3 is a high-pressure side cylinder attached to the crankcase 2, and 4 is a low-pressure side cylinder attached to the crankcase 2. In the present embodiment, the compressor body 1 is provided with two high-pressure and low-pressure cylinders 3 and 4, and the pair of cylinders 3 and 4 are attached to face each other with the crankcase 2 interposed therebetween. The crankcase 2 is provided with flanges 18 and 19, and cylinders 3 and 4, cylinder packings 20 and 21, air valves 22 and 23, head packings 24 and 25, and cylinder heads 16 and 17 are stacked on the flanges 18 and 19. The compression chambers 30 and 31 are formed by arranging and fixing with through bolts 28 and 29 (FIG. 2).

  A piston 32 includes lip rings 33 and 34 for compressing air and the like, and rider rings 41 and 42 for preventing the compression portion and the cylinders 3 and 4 from coming into contact with each other. The piston 32 is fixed to the connecting rod 11 via a small end bearing 35 and a piston pin 36. Retainers 37 and 38 are fixed to both ends of the piston 32 so as to sandwich the lip rings 33 and 34 with set screws 39 and 40, respectively. In this structure using the piston 32 in which the low pressure side compression part and the high pressure side compression part are integrated, the process (stroke) at the time of the compression process is the same for both low pressure and high pressure. By molding the outer diameters with different dimensions, a two-stage compression is performed by producing a process volume difference between a low pressure and a high pressure.

  Next, the operation of the compressor body 1 in this embodiment will be described. In the compressor body 1 in this embodiment, when the crankshaft 6 is rotated by driving the rotor 12, the piston 32 having the lip rings 33 and 34 and the rider rings 41 and 42 is formed by the eccentric motion of the connecting rod 11. Reciprocating motion in the 31.

  In the low pressure side suction process in which the lip ring 34 that performs the first stage compression goes from the top dead center to the bottom dead center, the air is sucked into the compression chamber 31 through the crankcase 2 and the cylinder 4, and the lip ring 34 is top dead. In the discharge process on the low pressure side toward the point, the sucked air is discharged through the air valve 23 and the cylinder head 17 while being compressed to about 0.7 MPa. The discharged compressed air is sent to the cylinder head 16 on the high pressure side through the pipe 43 (FIG. 3). In the second stage compression, as in the first stage compression, the compressed air sent to the cylinder head 16 is a pneumatic valve in the suction process on the high pressure side where the lip ring 33 goes from the top dead center to the bottom dead center. 22 is sucked into the compression chamber 30 and is compressed to 4.0 MPa or more in the high pressure side discharge process from the bottom dead center to the top dead center. Here, the compressed air compressed to 4.0 MPa or more is sent to the air tank 45 through the air valve 22, the cylinder head 16, and the pipe 44 and stored. The stored compressed air is depressurized to a required pressure by the pressure reducing valve 46 and taken out from the air outlet 47. The above is the details about the operation of the compressor.

  Next, when realizing weight reduction and downsizing, a piston 32 in which a low pressure side compression portion and a high pressure side compression portion are integrally formed is mounted, and the rotation axis of the crankshaft and the compression direction of the piston are in relation to the ground plane. Problems occurring in the compressor laid out horizontally will be described with reference to FIGS. 4 to 9 in comparison with the operation of a general piston type reciprocating compressor.

  FIG. 4 shows a compression portion of a general piston type compressor. The piston has a small end, and the shaft rotates through the eccentric part 48 so that the piston 49 reciprocates in the cylinder 50. As described in Patent Document 1, since the conventional structure has one piston with one compression section, two mechanisms as shown in FIG. 4 are mounted on the compressor body. Perform compression. For example, in a portable compressor used for nailing machines, painters, etc., the atmospheric pressure is compressed to about 0.6 to 0.8 MPa by the first stage compression, and the first stage is compressed by the second stage compression. Compress the air to 4.0 MPa or higher. F shown in FIG. 4 is a piston load, and F1 and F2 are their component forces. F1 is a load received by the connecting rod, and F2 is a load by which the piston 49 is pressed against the cylinder 50. If the motor rotation direction is counterclockwise as shown in FIG. 4, F2 works in the upper direction opposite to gravity.

  FIG. 5 shows a change in the load F2 for one cycle in which the crankshaft makes one rotation when the compression unit of FIG. 4 is provided in the first stage of the two-stage compression. In this figure, as shown in FIG. 4, the crank angle θ is 0 ° where the piston is located at the bottom dead center. During the compression process in which the piston 49 heads to the top dead center, the load F2 is maximized and works upward. On the other hand, in the suction process in which the piston 49 heads toward the bottom dead center, the piston load is not generated because the air is sucked, and F2 that is a component force thereof is not generated.

  6 and 7 are models showing the load when the integral piston is compressed, and the rotation direction is the same counterclockwise as in FIG. The crank angle θ is set to 0 ° at the point where the low pressure side compression portion is located at the bottom dead center. FIG. 6 shows the first-stage compression in the two-stage compression. The compression part on the low pressure side is the compression process, and the compression part on the high pressure side is the suction process. For example, in the portable compressor used in the nailing machine described above, the atmosphere is compressed to about 0.7 MPa by the first stage compression. Since the air compressed on the low pressure side passes through the piping and the like and is sent to the high pressure side, a pressure of 0.7 MPa is also applied to the high pressure side compression portion. FIG. 7 shows the second-stage compression in the two-stage compression, where the high-pressure side compression section is the compression process and the low-pressure side compression section is the suction process. Here, the high pressure side compression section compresses 0.7 MPa air compressed by the first stage compression to about 4.2 MPa, and the low pressure side compression section sucks air into the cylinder through a filter and an air valve. In this first and second stage compression, the direction of the piston load F and its component force F1 received by the connecting rod is switched, but the load F2 against which the piston is pressed against the cylinder is always upward in the direction opposite to gravity. Works.

  FIG. 8 shows a change in the load F2 for one cycle in which the crankshaft makes one rotation in the models of FIGS. During the crank angle of 0 to 180 °, the low pressure side is the compression process and the high pressure side is the suction process, and during the crank angle of 180 to 360 °, the high pressure side is the compression process and the low pressure side is the suction process. The load F2 that presses the piston against the cylinder always acts in the upward direction.

  FIG. 9 is a front view (left side) and a cross-sectional view (right side) of a compression unit including an integral piston. Reference numeral 67 denotes a piston in which a low pressure side compression portion and a high pressure side compression portion are integrally formed, and includes a low pressure side lip ring 70, a high pressure side lip ring 71, a low pressure side rider ring 68, and a high pressure side rider ring 69. Reference numerals 72 and 73 are retainers for fixing the lip rings 70 and 71. During the compression process, the compressed air enters between the lip rings 70 and 71 and the retainers 72 and 73, thereby increasing the outer diameter of the lip ring and forming a seal line with the cylinder to perform compression. On the other hand, the rider rings 68 and 69 receive a force by which the piston is pressed against the cylinder by the piston load, and prevent the compression portion from coming into contact with the cylinder when the lip rings 70 and 71 are worn.

  In the integrated piston model shown in FIGS. 6 and 7, the low pressure side is the suction step during the second stage (high pressure side) compression process, but the cylinder internal pressure is 0 MPa because the air is sucked in, and the low pressure side lip The ring is not stretched, that is, the compressed air does not enter the gap between the low-pressure lip ring and the retainer. If the lip ring or rider ring on the low pressure side wears during operation, the lip ring is not stretched in the suction process on the low pressure side, so the outer diameter of the ring is smaller than the inner diameter of the cylinder, and the compression part is in the cylinder. It will be. In this state, in the early stage of the low-pressure side compression process (crank angle 180 ° to 225 ° in FIG. 8), there is also an influence of gravity, and the low-pressure side compression portion is positioned below the cylinder. From the end to the end (crank angle 225 ° to 360 ° in FIG. 8), the component force F2 of the piston load generated during the high pressure side compression process acts in the direction opposite to gravity (cylinder upper direction). The problem was that the low pressure side compression part was struck from the lower side of the cylinder to the upper side while the ring outer diameter had a backlash, resulting in increased noise.

  On the other hand, in the case of the low pressure side compression process, the pressure generated in the cylinder due to the compression causes the low pressure side lip ring to be stretched, so there is no play between the cylinder inner diameter and the ring outer diameter. Even if the component force F2 of the piston load is generated, it is not suddenly struck in the cylinder upper direction, and it does not cause excessive noise.

  Also in the conventional piston type shown in FIGS. 4 and 5, if the ring is worn by operation, a backlash occurs between the inner diameter of the cylinder and the outer diameter of the ring. However, unlike the integral piston, the piston moves into the cylinder during the suction process. Since the pressing load F2 does not occur, even if there is a backlash between the cylinder inner diameter and the ring outer diameter, the piston moves toward the bottom dead center while being constantly pressed to the lower side of the cylinder by gravity. According to this, since there is no operation in which the piston is struck against the cylinder when there is a backlash between the inner diameter of the cylinder and the outer diameter of the ring, noise that becomes a problem with the integral piston does not occur.

  Next, the present embodiment will be described with reference to FIGS. 10A, 10B, 11 and 12. FIG. In the present embodiment, in a state where the inner diameter of the cylinder and the outer diameter of the ring are loose, the low-pressure side compression portion is struck from the lower side of the cylinder to the upper side, and noise is prevented from being generated. This embodiment is premised on a structure in which low-pressure and high-pressure pistons are integrated, a small-end bearing is provided in the low-pressure side piston portion, and two-stage compression is performed with a single connecting rod. And as shown to FIG. 10A, when arrange | positioning a low voltage | pressure side compression part and a small end part bearing on the right side, it arrange | positions so that the rotation direction of a motor may turn clockwise. As shown in FIG. 11, when the low-pressure side compression part and the small-end bearing are arranged on the left side, the rotation direction of the motor is arranged counterclockwise.

  FIG. 10A is a diagram showing a high pressure side compression process in which the integrated piston moves leftward when the low pressure side compression portion and the small end bearing are arranged on the right side and the high pressure side compression portion is arranged on the left side. The rotation direction of the motor is set clockwise. As shown in the figure, the load F2 with which the low-pressure side piston is pressed against the cylinder is directed in the cylinder lower side (gravity) direction. FIG. 10B is a view showing a low-pressure side compression process in which the integral piston moves rightward in the same arrangement, and the rotation direction of the motor is set clockwise. As shown in the figure, the load F2 with which the low-pressure side piston is pressed against the cylinder is also directed in the cylinder lower side (gravity) direction.

  FIG. 12 shows a change in the load F2 with which the low-pressure side piston is pressed against the cylinder with respect to the change in the crank angle θ in the compression model of the integrated piston in FIGS. 10A and 10B. As shown in FIGS. 10A and 10B, by defining the positions of the low-pressure side compression portion and the small end bearing and the rotation direction of the motor, the load F2 always acts in the lower (gravity) direction of the cylinder as shown in FIG. . As a result, in the second stage compression (compression on the high pressure side) of the integral piston, each ring is worn by operation, the outer diameter of the lip ring and rider ring becomes smaller than the inner diameter of the cylinder on the low pressure side, and the suction on the low pressure side Even if there is play between the cylinder inner diameter and the lip ring outer diameter because the lip ring is not stretched, the low pressure side compression part is always pressed in the cylinder lower side (gravity) direction. There is no movement of the piston hitting the upper side of the cylinder, and noise due to this cause does not occur. In addition, by providing the small end bearing on the low pressure side, the temperature of the low pressure side compression section is lower, so the load applied to the small end bearing can be reduced.

  In this embodiment, it is assumed that the rotation axis of the crankshaft and the compression direction of the piston are horizontal, but the axial direction of the rotation axis of the crankshaft and the compression direction of the piston (piston If the inclination angle of the reciprocating direction (within the reciprocating direction) with respect to the horizontal direction is within the maximum swing angle of the connecting rod, the low-pressure side compression part is always pressed in the cylinder lower side (gravity) direction. Can be obtained. Also, since the bottom surface of the compressor is installed on the horizontal installation surface, the configuration of the compressor is such that the inclination angle of the piston compression direction (piston reciprocating direction) with respect to the compressor bottom surface is the maximum of the connecting rod. It may be within the swing angle.

  According to the present embodiment, it is possible to prevent noise from being generated due to the low pressure side compression portion being struck from the lower side of the cylinder to the upper side when there is a backlash between the cylinder inner diameter and the ring outer diameter.

DESCRIPTION OF SYMBOLS 1 Compressor body 2 Crankcase 3, 4 Cylinder 5 Motor 6 Crankshaft 8 Main bearing 10 Large end bearing 11 Connecting rod 13 Cooling fan 16, 17 Cylinder head 30, 31 Compression chamber 32 Piston 33, 34 Lip ring 35 Small end Part bearing 36 piston pin 37, 38 retainer 41, 42 rider ring 44 piping 45 air tank 46 pressure reducing valve 48 eccentric part 49 piston 50 cylinder 67 piston 68, 69 rider ring 70, 71 lip ring 72, 73 retainer

Claims (10)

A drive shaft driven and rotated by a motor;
A first cylinder and a second cylinder provided opposite to each other;
A connecting rod connected to the drive shaft and swinging;
A piston connected to the connecting rod and reciprocating in the first cylinder and the second cylinder;
The piston is provided with a lip ring that seals between the piston and the first cylinder or the second cylinder,
An inclination angle with respect to the horizontal direction of the axial direction of the drive shaft and the reciprocating direction of the piston is within a maximum swing angle of the connecting rod,
The drive is performed so that the piston is pressed in the direction of gravity in the first cylinder or the second cylinder during a compression process of compressing the fluid in the first cylinder and the second cylinder, respectively. A compressor characterized in that the rotation direction of the shaft is set.   2. The compressor according to claim 1, wherein the fluid compressed in the first cylinder is further compressed in the second cylinder.   The lip ring seals the piston and the first cylinder or the second cylinder by opening radially outward when the pressure in the first cylinder or the second cylinder rises. The compressor according to claim 1.   2. The compressor according to claim 1, wherein the drive shaft is a crankshaft in which a portion connected to the connecting rod is eccentric. The piston has an eccentric part connected to the drive shaft,
The compressor according to claim 1, wherein a tip end of the drive shaft is connected to a position that is eccentric with respect to a rotation center of the eccentric part.   The compressor according to claim 2, wherein a small end bearing for connecting the piston and the connecting rod is provided on the first cylinder side.   The rotation direction of the drive shaft is set clockwise when the first cylinder is disposed on the right side and the second cylinder is disposed on the left side when viewed from the axial direction of the drive shaft. 6. The compressor according to 6.   The rotation direction of the drive shaft is set counterclockwise when the first cylinder is disposed on the left side and the second cylinder is disposed on the right side when viewed from the axial direction of the drive shaft. Item 7. The compressor according to Item 6.   The compressor according to claim 3, wherein the piston is provided with a rider ring in addition to the lip ring, and the lip ring is fixed by a retainer. A crankshaft driven by a motor and rotating,
A first cylinder on the low pressure side and a second cylinder on the high pressure side provided opposite to each other;
A connecting rod connected to the crankshaft and swinging;
A piston connected to the connecting rod and reciprocating in the first cylinder and the second cylinder;
The piston is provided with a lip ring that seals between the piston and the first cylinder or the second cylinder,
The inclination angle of the piston in the reciprocating direction with respect to the bottom surface of the compressor is within the maximum swing angle of the connecting rod,
In the compression step of compressing the fluid in the second cylinder and in the suction step of sucking the fluid into the first cylinder, the piston is pressed in the direction of gravity in the first cylinder. A compressor characterized in that the direction of rotation of the crankshaft is set.

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