JP2011247099A - Electric motor integrated booster compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve high power and energy saving of a booster compressor by suppressing a variation of rotational torque per rotation of an electric motor, in the electric motor integrated booster compressor.SOLUTION: A pair of compressor units 11a, 11b to which cylinder heads 28a, 28b, cylinders 12a, 12b and crank casings 14a, 14b are integrally connected are connected to both sides of an electric motor casing 16. Both ends of an output shaft 36 of the electric motor 20 accommodated in the electronic motor casing 16 are connected to crankshafts 17a, 17b of both compressor units, and the crank arms 18a, 18b of both compressor units are connected to the output shaft 36 at angles of 180°, respectively. Stroke positions of pistons 38a, 38b of both compressor units are directly opposite to each other.

Description

  The present invention relates to a motor-integrated booster compressor in which an electric motor casing is integrally provided. More specifically, the compressor unit is connected to both sides of the electric motor casing, thereby reducing fluctuations in rotational torque applied to the electric motor. It is related with the booster compressor made to do.

  Patent Document 1 discloses an example of a conventional electric motor-integrated booster compressor. Hereinafter, the configuration of the booster compressor will be described with reference to FIG. In FIG. 3, the booster compressor 100 accommodates a cylinder 102 that forms a compression space c, a crank casing 104 that forms a crank chamber r, and an electric motor 110 that drives a crankshaft 107 provided in the crank chamber. The motor casing 106 is integrally formed.

  The crankshaft 107 is connected between a pair of crank arms 108 and a pair of crank arms 108 via a connecting shaft 109 that is mounted at an eccentric position with respect to the crankshaft 107. A discharge port 114 is provided in the top wall 112 of the cylinder 102, and a check discharge valve 116 is provided in the discharge port 114. A cylinder head 118 is mounted on the top surface of the top wall 112, and the compressed gas g compressed in the compression space c is discharged into the cylinder head 118 through the discharge port 114 and further drilled in the cylinder head 118. It is discharged from the discharge hole 120.

  The lower end of the cylinder 102 is connected to the upper surface opening of the sealed crank casing 104, and the sealed motor casing 106 having the air introduction holes 122 is connected to the side wall surface of the crank casing 104. The crankshaft 107 is rotatably supported by bearings 124 and 124, and the output shaft 126 of the electric motor 110 is connected to the crankshaft 107 in the axial direction.

  A piston 128 that slides inside the cylinder 102 is connected to a connecting shaft 109 by a piston rod 130. The connecting shaft 109 and the piston rod 130 are connected via a bearing 132 so that they can rotate relative to each other. An air supply groove 136 is formed in the inner surface of the cylinder 102 in the axial direction.

  A pressurized compressed gas g, such as nitrogen gas, flows into the electric motor casing 106 from the air introduction holes 122 and flows across the electric motor 110. The compressed gas g further flows into the crank chamber r from a vent hole 134 formed in the side wall of the crank casing 104. When the output shaft 126 is driven to reciprocate the piston 128, the piston 128 descends and the upper end opening of the air supply groove 136 communicates with the compression space c.

Therefore, the compressed gas g in the crank chamber r flows into the compression space c through the air supply groove 134. As soon as the piston 128 enters the upward stroke, the air supply groove 136 is closed, and the compressed gas g in the compression space c is further pressurized, pushes the check discharge valve 116 open, and is discharged from the cylinder head 118.

JP 2007-51615 A

FIG. 2 is a diagram schematically showing torque fluctuations generated per rotation on the output shaft of the electric motor of the compressor. In FIG. 2, a curve A is a torque fluctuation of a general compressor, and a region B surrounded by the curves B ₁ and B ₂ and a curve B ₃ show a torque fluctuation of the booster compressor. In the compression process of a general compressor, the pressure of the compressed gas in the compression space acts on the piston in the direction opposite to the direction of rotation of the crankshaft, so that the torque increases and the crank arm moves 130 ° from the bottom dead center. It becomes the maximum in the place where the angle difference of the neighborhood becomes. Thereafter, the torque gradually decreases and reaches zero at the top dead center. In the suction process, the pressure of the compressed gas does not act on the piston, so the torque is maintained at zero.

In the booster compressor, since the pressurized gas is introduced into the compression space, the pressure applied to the piston from the gas to be compressed in the compression process is larger than that of a general compressor. Therefore, in the compression process, the torque is increased as compared with a general compressor. The intake stroke, pressure of the compressed gas of the compression space is because they act in the direction of assisting the rotation of the crankshaft, as shown as curve B _3, the generated torque becomes negative.

  There is also a booster compressor having a structure in which a cylinder head includes a suction port and a discharge port, and sucks compressed gas from the suction port into a compression space. In the booster compressor disclosed in Patent Literature 1, the pressure of the compressed gas under pressure introduced into the crank chamber in the compression process is applied to the piston from below the piston to assist the rotation of the crankshaft. Therefore, compared with the booster compressor having the above-described structure, the rotational torque generated on the output shaft of the motor in the compression process can be reduced.

  However, even in the booster compressor disclosed in Patent Document 1, the fluctuation per one rotation of the rotational torque applied to the output shaft of the electric motor has not been eliminated. For this reason, the current value of the electric motor fluctuates per one rotation, which causes a problem that the rotational speed of the electric motor is not stable. Therefore, it is necessary to attach a rotation fluctuation suppressing member such as a flywheel or a balance weight to the crankshaft, resulting in high costs and high output and energy saving of a booster compressor using an electric motor are difficult. .

  SUMMARY OF THE INVENTION In view of the problems of the prior art, the present invention provides a booster compressor integrated with an electric motor that suppresses fluctuations in rotational torque per rotation of the electric motor and enables higher output and energy saving of the booster compressor. Let it be an issue.

In order to solve such a problem, the electric motor integrated booster compressor of the present invention is
In a motor-integrated booster compressor in which a cylinder that forms a compression space, a crank casing that forms a crank chamber, and a motor casing that houses a motor that drives a crankshaft provided in the crank chamber are integrally connected. ,
A pair of compressor units formed by connecting the cylinder and the crank casing are arranged on both sides of the motor casing, and the crank casings of both compressor units are connected to the motor casing,
The crankshafts of both compressor units are connected to both ends of the output shaft of the electric motor, respectively, and the difference in time between the strokes of the pistons of both compressor units is made by giving an angular difference in the connecting angle of the crank arms of both compressor units to the output shaft. It is a thing with.

In the device according to the present invention, by applying a difference in the connecting angle between the crank arms of the compressor units connected to both ends of the output shaft of the electric motor, the pressure of the compressed gas applied to the output shaft from both compressor units is reduced. Hold on. As a result, the torque generated on the output shaft per rotation can be leveled to a low value. As a result, the rotation speed of the electric motor is stabilized, so that the output of the electric motor can be increased and energy can be saved.
Further, since the torque generated on the output shaft per rotation can be leveled, it is not necessary to attach a torque fluctuation suppressing member such as a flywheel to the crankshaft, and the booster compressor can be reduced in size and cost.

  In the device of the present invention, the angle difference between the connecting angles of the crank arms with respect to the output shafts of both compressor units is preferably in the range of 150 to 210 °. By making the angle difference between the coupling angles within this range, the effect of reducing the pressure of the compressed gas applied to the motor output shaft is greatly improved, so that the torque generated by the output shaft can be greatly reduced.

  In the device according to the present invention, when the angle difference between the connecting angles is 180 °, the killing effect is maximized. As a result, the torque fluctuation per rotation of the output shaft of the electric motor can be leveled to the lowest value, so that the electric motor can be driven most stably.

According to the motor-integrated booster compressor of the present invention, the cylinder that forms the compression space, the crank casing that forms the crank chamber, and the motor casing that houses the electric motor that drives the crankshaft provided in the crank chamber. In the motor-integrated booster compressor integrally connected, a pair of compressor units in which the cylinder and the crank casing are connected are arranged on both sides of the motor casing, and the crank casings of both the compressor units are connected to the compressor casing. It is connected to the motor casing, the crankshafts of both compressor units are connected to both ends of the output shafts of the motors, respectively, and the connecting angle of the crank arms of both compressor units with respect to the output shafts is given an angular difference. Since the piston stroke process has a time difference, the output of the motor Can level the torque per revolution generated in a low value, thereby, the rotation of the motor is stabilized, it is possible to high power and energy saving of the electric motor.
Further, since the torque generated per rotation can be leveled, it is not necessary to attach a torque fluctuation suppressing member such as a flywheel or a balance weight to the crankshaft, and the cost is reduced.

It is a front view sectional view concerning one embodiment of the booster compressor of the present invention. It is a diagram which shows typically the torque fluctuation which generate | occur | produces per rotation in the electric motor of a compressor. It is front view sectional drawing of the conventional electric motor integrated booster compressor.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

  One embodiment of a booster compressor integrated with an electric motor according to the present invention will be described with reference to FIG. In FIG. 1, the motor-integrated booster compressor 10 according to the present embodiment has a pair of compressor units 11 a and 11 b erected on both sides of an electric motor casing 16. The electric motor 20 is accommodated in the electric motor casing 16, and the output shaft 36 of the electric motor 20 protrudes from both sides of the main body case of the electric motor 20 toward the compressor units 11a and 11b. The electric motor casing 16 is provided with an air guide pipe 32 for sucking compressed gas g, such as nitrogen gas, that has already been pressurized into the electric motor casing 16 from a gas supply device (not shown).

  Hereinafter, the compressor unit 11a is composed of a cylinder head 28a, a cylinder 12a, and a crank casing 14a in order from above, and these are integrally connected to each other. The compressor unit 11a and the compressor unit 11b have the same configuration, and the configuration will be described taking the compressor unit 11a as an example.

  A discharge port 24a is formed in the top wall 22a of the cylinder 12a, and a check discharge valve 26a is provided in the discharge port 24a. A hollow cylinder head 28a is mounted on the top surface of the top wall 22a. The compressed gas g is compressed in the compression space c1 formed above the piston 40a in the cylinder 12a, and then the compressed gas g is discharged into the cylinder head 28a through the discharge port 24a. It discharges to the gas supply destination from the discharge hole 30a drilled in 28a.

  A lower end of the cylinder 12a is connected to an upper surface opening of the sealed crank casing 14a, and an electric motor casing 16 is integrally connected to a side surface of the crank casing 14a. A vent hole 44a is formed in the side surface of the crank casing 14a to which the motor casing 16 is connected. The crankshaft 17a is rotatably supported by bearings 34a, 34a, and the output shaft 36 of the electric motor 20 is connected coaxially with the crankshaft 17a. A crank chamber r1 is formed in the crank casing 14a.

  The crankshaft 17a is connected at a central portion via a pair of crank arms 18a arranged in parallel, and a connecting shaft 19a mounted between the crank arms at an eccentric position with respect to the crankshaft 17a. . The piston 38a that slides inside the cylinder 12a is connected to the connecting shaft 19a by a piston rod 40a. The piston rod 40a and the connecting shaft 19a are connected via a bearing 42a so that they can rotate relative to each other. An air supply groove 46a is formed in the inner surface of the cylinder 12a in the axial direction.

  In the present embodiment, the crank arm 19a of the compressor unit 11a and the crank arm 19b of the compressor unit 11b are connected to the output shaft 36 with an angular difference of 180 °. Therefore, for example, when the piston 38a is located at the top dead center, the piston 38b is located at the bottom dead center.

  In such a configuration, a pressurized gas g to be compressed, for example, nitrogen gas, flows from the air guide pipe 32 into the motor casing 16. The compressed gas g that has flowed in crosses the electric motor 20 and cools the electric motor 20. Thereafter, the compressed gas g flows into the crank chamber r1 or r2 through the vent holes 44a and 44b. The compressed gas g flowing into the crank casings 14a and 14b cools the bearings 34a, 34b, 42a and 42b, and the like. Thereafter, the compressed gas g flows into the air supply grooves 46a and 46b.

  When the electric motor 20 is operated and the output shaft 36 is rotated, the pistons 38a and 38b reciprocate. When the pistons 38a and 38b descend in the suction process, the upper ends of the air supply grooves 46a and 46b communicate with the compression space c. Therefore, the compressed gas g flows into the compression space c1 or c2 through the air supply groove 44a or 44b. When the pistons 38a and 38b enter the ascending stroke in the compression process, the air supply grooves 44a and 44b are immediately closed, and the compressed gas g in the compression spaces c1 and c2 is further pressurized, and the check discharge valves 26a and 26b are opened. It pushes open and is discharged into the cylinder heads 28a and 28b. Thereafter, the compressed gas g is discharged from the discharge holes 30a and 30b.

According to the present embodiment, since the movement of the piston 38a and the piston 38b is shifted by 180 °, assuming that only one of the compressor units 11a and 11b is connected to the output shaft 36, torque generated in the output shaft 36 of the motor 20, so each region B or the curve B _3.
On the other hand, when the compressor units 11a and 11b are connected to the output shaft 36 as in this embodiment, the pressures of the compressed gas g applied to the output shaft 36 from both compressor units are mutually reduced. Therefore, the generated torque of the output shaft 36 is as shown by the curve C.

  Thus, the torque generated in the output shaft 36 per rotation is reduced and leveled. Therefore, since the rotation speed of the electric motor 20 is stabilized, the output of the electric motor 20 can be increased and energy can be saved. Further, since the torque generated per rotation can be leveled, it is not necessary to attach a torque fluctuation suppressing member such as a flywheel or balance weight to the crankshaft 17a, and the booster compressor can be reduced in size and cost. .

Further, in the booster compressor 10 of the present embodiment, the pressurized compressed gas g is once introduced into the crank chambers r ₁ and r ₂ , so that the pistons 38a and 38b are compressed from the compressed gas g in the compression spaces c1 and c2. Is reduced by the compressed gas g in the crank chamber. Therefore, the torque generated in the output shaft 36 can be reduced.
Further, since the crank chamber is in a pressurized state, there is no possibility that air in the atmosphere will enter the crank chamber and reduce the concentration of the compressed gas g.

  Further, since the compressed gas g is passed through the motor casing 16 and the crank casings 14a and 14b, it is possible to effectively cool the motor 20 in the motor casing and the bearings in the crank casing. it can.

  According to the experiments by the present inventors, when the angle difference between the crank arms of both compressor units is 150 to 210 °, the reduction and leveling of the rotational torque generated on the motor output shaft per revolution is remarkable. I understood it. In particular, it was found that when the angle difference is 180 °, the reduction and leveling of the rotational torque is most remarkable.

  In addition, although the said embodiment is a case where it applies to the booster compressor of the system which introduces to-be-compressed gas once into a crankcase, and introduces it into compression space after that, this invention device is a booster compressor other than this system, For example, as described above, the present invention can also be applied to a booster compressor having a structure in which a cylinder head includes a suction port and a discharge port and sucks compressed gas from the suction port into a compression space.

  According to the present invention, in the motor-integrated booster compressor, the rotational torque generated in the motor is leveled to a low value, the rotation of the motor is stabilized, and high output and energy saving of the motor are enabled.

10,100 Motor-integrated booster compressor 12a, 12a, 102 Cylinder 14a, 14b, 104 Crank casing 16, 106 Motor casing 17a, 17b, 107 Crank shaft 18a, 18b, 108 Crank arm 19a, 19b, 109 Connecting shaft 20, 110 Electric motor 22a, 22b, 112 Top wall 24a, 24b, 114 Discharge port 26a, 26b, 116 Check discharge valve 28a, 28b, 118 Cylinder head 30a, 30b, 120 Discharge hole 32, 122 Air guide hole 34a, 34b, 42a, 42b, 124, 132 Bearing 36, 126 Output shaft 38a, 38b, 128 Piston 40a, 40b, 130 Piston rod 44a, 44b, 134 Air supply groove c, c1, c2 Compressed space g Compressed gas r, r1, r2 Rank room

Claims (3)

In a motor-integrated booster compressor in which a cylinder that forms a compression space, a crank casing that forms a crank chamber, and a motor casing that houses a motor that drives a crankshaft provided in the crank chamber are integrally connected. ,
A pair of compressor units formed by connecting the cylinder and the crank casing are arranged on both sides of the motor casing, and the crank casings of both compressor units are connected to the motor casing,
The crankshafts of both compressor units are connected to both ends of the output shaft of the electric motor, respectively, and the difference in time between the strokes of the pistons of both compressor units is made by giving an angular difference in the connecting angle of the crank arms of both compressor units to the output shaft. An electric motor-integrated booster compressor characterized by having   The motor-integrated booster compressor according to claim 1, wherein an angle difference between the connection angles is in a range of 150 to 210 °.   The motor-integrated booster compressor according to claim 2, wherein an angle difference between the coupling angles is 180 °.

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