JPH09158846A - Air compressing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold pressure of compressed air passing an air feed pipe to a constant level regardless of change of the using rate of compressed air in a demand by interposing a continuously variable transmission in a power transmitting passage between an oil cooling type air compressor and a motor for driving the air compressor. SOLUTION: In an air compressing unit, when a compressor 1 is driven by a motor 28, air is intaked into the compressor 1, air is compressed, compressed air is led into an oil separator 6, and compressed air is supplied to a demand after oil in compressed air is separated. In this case, a continuously variable transmission 30 is interposed in a power transmitting passage arranged between the compressor 1 and the motor 28. In the case where pressure of compressed air which is passed in an air feed pipe 31 is fluctuated by change of the using rate of compressed air in the demand, the detected signal of a pressure sensor 32 is applied, the continuously variable transmission 30 is controlled by the controller 33, a change ratio is changed, and thereby, rotational speed of the compressor 1 is regulated, and pressure of compressed air which is passed the air feed pipe 31 is held to a constant level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air compression unit having an oil-cooled air compressor driven by a motor.

[0002]

2. Description of the Related Art A system diagram of a conventional air compression unit of this type is shown in FIG. When the oil-cooled compressor 1 is driven by the motor 28, air flows through the air filter 2, the check valve 3,
It is sucked into the compressor 1 through the suction pipe 4 and compressed. The compressed air discharged from the compressor 1 is introduced into the oil separator 6 through the discharge pipe 5, and is turned inside to separate most of the oil contained in the compressed air.

Next, the compressed air separates the oil remaining in the cylindrical oil separator element 7 in the process of flowing from the outside to the inside, and then the check valve 8, the flexible hose 9 and the opening / closing. It is supplied to the customer through the operation valve 10.

The oil separated from the compressed air by the oil separator 6 drops and is temporarily stored in the lower part thereof. And
This oil O is extracted from the bottom of the oil separator 6 by the oil return pipe 11, enters the oil cooler 13 via the flexible hose 12, is cooled by the outside air blown by the fan 29, and then is flexible hose. 14, the temperature control valve 15, the oil filter 16, the electromagnetic on-off valve 17, and the orifice 18, and enters the suction pipe 4, and is sucked into the compressor 1 along with the air flowing therein.

The oil separated from the compressed air by the oil separator element 7 accumulates in the oil pan 7A that covers the lower end opening of the oil separator element 7, and the suction pipe
The gas enters the suction pipe 4 through the check valve 20, the check valve 20, and the capillary tube 21, and is sucked into the compressor 1 along with the air flowing therein.

When the temperature of the oil passing through the temperature control valve 15 falls below a predetermined value, the temperature control valve 15 is opened, which causes the oil return pipe.
The oil from 11 is guided to the oil filter 16 through the bypass pipe 22 and the temperature control valve 15. In addition, 23 is an air vent pipe, and this air vent pipe 23 has a safety valve 24, a pressure switch 25, a pressure gauge 26,
An electromagnetic opening / closing valve 27 is provided.

[0007]

The above-described conventional air compression unit has a problem that its pressure fluctuates as the amount of compressed air used in the demand destination changes. In order to deal with this, it has been proposed to install a reserve tank for temporarily storing compressed air, but this has a problem that the reserve tank becomes large and its cost and installation space increase.

[0008]

SUMMARY OF THE INVENTION The present invention has been invented to solve the above-mentioned problems, and its gist is to provide an oil-cooled air compressor driven by a motor and this air compressor. An oil separator is provided which separates oil in compressed air compressed by the compressor and takes out compressed air from the air supply pipe, and an oil return circuit which returns the oil separated by this oil separator to the suction side of the air compressor. In the air compression unit, there is provided a continuously variable transmission in a power transmission system path between the motor and the air compressor.

Another feature is that the pressure of the compressed air passing through the air supply pipe is made constant by adjusting the rotational speed of the air compressor of the continuously variable transmission and changing the discharge amount thereof. There is a controller to control.

However, the power of the motor is transmitted to the air compressor via the continuously variable transmission, and the discharge amount is changed by controlling the continuously variable transmission by the controller to adjust the rotation speed of the air compressor. Then, the pressure of the compressed air passing through the air supply pipe is maintained constant.

[0011]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the invention is shown in FIG. As shown in FIG. 1, a continuously variable transmission 30 is provided in a power transmission path between the air compressor 1 and the motor 28. A pressure sensor 32 is provided on the air supply pipe 31 of the oil separator 6, and the detected pressure is input to the controller 33.

The controller 33 outputs the continuously variable transmission 30 to control it. Other configurations are the same as those of the conventional one shown in FIG. 2, and corresponding members are denoted by the same reference numerals and the description thereof is omitted.

However, when the pressure of the compressed air passing through the air supply pipe 31 fluctuates due to a change in the amount of compressed air used at the demand destination, the controller 33 receives a signal from the pressure sensor 32 which detects this and the controller 33 causes the continuously variable transmission 30 to operate. To adjust the rotational speed of the air compressor 1 to change its discharge amount and maintain the pressure of the compressed air passing through the air supply pipe 31 constant.

The continuously variable transmission 30 is not limited to the belt type shown in the figure, and it goes without saying that a cup type or any other type and structure can be adopted.

[0015]

According to the present invention, the power of the motor is transmitted to the air compressor through the continuously variable transmission, and the continuously variable transmission is controlled by the controller to adjust the rotation speed of the air compressor. The discharge amount can be changed to maintain the pressure of the compressed air passing through the air supply pipe constant. Also,
Since a large-sized reserve tank is not required, it contributes to downsizing of the air compression unit and its cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a system diagram of a conventional air compression unit.

[Explanation of symbols]

 1 Air compressor 28 Motor 6 Oil separator 11 Oil return pipe 30 Continuously variable transmission 31 Air supply pipe 32 Pressure sensor 33 Controller

Claims (2)

[Claims] 1. An oil-cooled air compressor driven by a motor, an oil separator for separating oil in compressed air compressed by the air compressor and extracting compressed air from an air supply pipe, and an oil separator. In an air compression unit equipped with an oil return circuit for returning the oil separated in step 1 to the suction side of the air compressor, a continuously variable transmission is provided in the power transmission path between the motor and the air compressor. An air compression unit. 2. A controller is provided for controlling the continuously variable transmission so that the pressure of the compressed air passing through the air supply pipe becomes constant by adjusting the rotation speed of the air compressor and changing the discharge amount thereof. The air compression unit according to claim 1, wherein: